Culture

ROCHESTER, Minn. -- The Mayo Clinic data scientists who developed highly accurate computer modeling to predict trends for COVID-19 cases nationwide have new research that shows how important a high rate of vaccination is to reducing case numbers and controlling the pandemic.

Vaccination is making a striking difference in Minnesota and keeping the current level of positive cases from becoming an emergency that overwhelms ICUs and leads to more illness and death, according to a study published in Mayo Clinic Proceedings. The study, entitled "Quantifying the Importance of COVID-19 Vaccination to Our Future Outlook," outlines how Mayo's COVID-19 predictive modeling can assess future trends based on the pace of vaccination, and how vaccination trends are crucial to the future course of the pandemic.

The Mayo researchers estimate that a peak of more than 800 patients would be in hospital ICUs in Minnesota this spring if no vaccines had been developed. The projections take into account new variants of the SARS-CoV-2 virus as well as current public health measures and masking standards.

The predicted ICU census levels would be more than double the number of Minnesota COVID-19 patients who were hospitalized in ICUs on Dec. 1, at the height of the most recent surge last year.

"It is difficult to untangle how much of this elevated rate of spread right now is due to new variants as opposed to changes in social behavior," the authors say, but "regardless of the reason, the absence of vaccinations in the current environment would have been likely to result in by far the largest surge to date."

If Minnesota had achieved vaccination of 75% of the population by early April, the study estimates that the 7-day average of cases per 100,000 residents, the number of COVID-19 patients hospitalized and the number in ICUs would plummet by early July. "According to the model, this level of vaccination would completely suppress the growth (even in the face of the recent elevated spread rate) and immediately drive cases and hospitalizations down to very low levels," the authors say.

The Mayo Clinic study was led by Curtis Storlie, Ph.D., and Sean Dowdy, M.D., whose team developed the computer model for forecasting COVID-19's impact on hospital usage that has helped guide Mayo's response to the pandemic. Mayo Clinic's predictive modeling also has been shared with Minnesota public health leadership to help inform critical decisions over the past year.

Mayo Clinic's forecasting of COVID-19 trends nationally is available online at the Mayo Clinic COVID-19 Resource Center. The Coronavirus Map tracking tool has county-by-county information on COVID-19 cases and trends nationwide.

When the pandemic emerged last year, Mayo Clinic data scientists developed predictive modeling to assess when and where COVID-19 hot spots would occur. The model accurately predicted the timing and magnitude of COVID-19 case and hospitalization surges, which enabled Mayo Clinic to prepare and assure it could provide the best care while keeping patients and staff safe.

The United Kingdom government plans to implement mass scale population testing for SARS-CoV-2 infection using Lateral Flow Devices (LFDs), yet the devices' sensitivity is unknown. A study published in the open access journal PLOS Biology by Alan McNally at University of Birmingham, UK, and colleagues suggests while LFDs are highly effective in identifying SARS-CoV-2 in individuals with high quantities of viral RNA present on the test swab, they are inaccurate at diagnosing infections in individuals with lower viral loads.

LFDs are increasingly used to increase testing capacity and screen asymptomatic populations for SARS-CoV-2 infection in mass surveillance programs, yet there are few data indicating the performance of these devices. To determine the sensitivity of LFDs, researchers tested the nasopharyngeal swabs of 8,000 university students using the devices. Next, they validated all positive samples and randomly selected 720 negative samples out of 7,187 negatives for validation.

Using reverse transcription PCR tests, the authors estimated the true COVID-19 prevalence rate and compared it to LFD test results. The researchers were able to determine the LFDs' accuracy rate for different levels of virus, finding that while the test was able to detect infections in samples with higher levels of viral RNA at a 100% accuracy rate, the test's performance dropped significantly in samples with lower viral loads.

The results suggest that for individuals in the very early or very late stages of infection, LFDs are likely to produce a false negative result, pointing to the need for frequent testing. A limitation of the study was that emergent variants and their potential effects on LFDs' sensitivity with asymptomatic cases were not considered within the scope of the study. Independent research suggests that both the UK and South African variants can be reliably detected, but further studies are needed to determine whether the LFDs can detect infections at the same viral loads as with the SARS-CoV-2 strain examined in the current research.

According to the authors, "When used regularly, LFDs can be a highly effective tool in reducing overall community burden. We would strongly recommend that Lateral Flow Device testing is used to screen people at a very regular frequency, and that a negative result should not be used to determine that someone is free from SARS-CoV-2 infection. As such LFDs should not be used as a test-to-do"

Forget diamonds--plastic is forever. It takes decades, or even centuries, for plastic to break down, and nearly every piece of plastic ever made still exists in some form today. We've known for a while that big pieces of plastic can harm wildlife--think of seabirds stuck in plastic six-pack rings--but in more recent years, scientists have discovered microscopic bits of plastic in the water, soil, and even the atmosphere. To learn how these microplastics have built up over the past century, researchers examined the guts of freshwater fish preserved in museum collections; they found that fish have been swallowing microplastics since the 1950s and that the concentration of microplastics in their guts has increased over time.

"For the last 10 or 15 years it's kind of been in the public consciousness that there's a problem with plastic in the water. But really, organisms have probably been exposed to plastic litter since plastic was invented, and we don't know what that historical context looks like," says Tim Hoellein, an associate professor of biology at Loyola University Chicago and the corresponding author of a new study in Ecological Applications. "Looking at museum specimens is essentially a way we can go back in time."

Caleb McMahan, an ichthyologist at the Field Museum, cares for some two million fish specimens, most of which are preserved in alcohol and stored in jars in the museum's underground Collections Resource Center. These specimens are more than just dead fish, though--they're a snapshot of life on Earth. "We can never go back to that time period, in that place," says McMahan, a co-author of the paper.

Hoellein and his graduate student Loren Hou were interested in examining the buildup of microplastics in freshwater fish from the Chicagoland region. They reached out to McMahan, who helped identify four common fish species that the museum had chronological records of dating back to 1900: largemouth bass, channel catfish, sand shiners, and round gobies. Specimens from the Illinois Natural History Survey and University of Tennessee also filled in sampling gaps.

"We would take these jars full of fish and find specimens that were sort of average, not the biggest or the smallest, and then we used scalpels and tweezers to dissect out the digestive tracts," says Hou, the paper's lead author. "We tried to get at least five specimens per decade."

To actually find the plastic in the fishes' guts, Hou treated the digestive tracts with hydrogen peroxide. "It bubbles and fizzes and breaks up all the organic matter, but plastic is resistant to the process," she explains.

The plastic left behind is too tiny to see with the naked eye, though: "It just looks like a yellow stain, you don't see it until you put it under the microscope," says Hou. Under the magnification, though, it's easier to identify. "We look at the shape of these little pieces. If the edges are frayed, it's often organic material, but if it's really smooth, then it's most likely microplastic." To confirm the identity of these microplastics and determine where they came from, Hou and Hoellein worked with collaborators at the University of Toronto to examine the samples using Raman spectroscopy, a technique that uses light to analyze the chemical signature of a sample.

The researchers found that the amount of microplastics present in the fishes' guts rose dramatically over time as more plastic was manufactured and built up in the ecosystem. There were no plastic particles before mid-century, but when plastic manufacturing was industrialized in the 1950s, the concentrations skyrocketed.

"We found that the load of microplastics in the guts of these fishes have basically gone up with the levels of plastic production," says McMahan. "It's the same pattern of what they're finding in marine sediments, it follows the general trend that plastic is everywhere."

The analysis of the microplastics revealed an insidious form of pollution: fabrics. "Microplastics can come from larger objects being fragmented, but they're often from clothing," says Hou--whenever you wash a pair of leggings or a polyester shirt, tiny little threads break off and get flushed into the water supply.

"It's plastic on your back, and that's just not the way that we've been thinking about it," says Hoellein. "So even just thinking about it is a step forward in addressing our purchases and our responsibility."

It's not clear how ingesting these microplastics affected the fish in this study, but it's probably not great. "When you look at the effects of microplastic ingestion, especially long term effects, for organisms such as fish, it causes digestive tract changes, and it also causes increased stress in these organisms," says Hou.

While the findings are stark--McMahan described one of the paper's graphs showing the sharp rise in microplastics as "alarming"--the researchers hope it will serve as a wake-up call. "The entire purpose of our work is to contribute to solutions," says Hoellein. "We have some evidence that public education and policies can change our relationship to plastic. It's not just bad news, there's an application that I think should give everyone a collective reason for hope."

The researchers say the study also highlights the importance of natural history collections in museums. "Loren and I both love the Field Museum but don't always think about it in terms of its day-to-day scientific operations," says Hoellein. "It's an incredible resource of the natural world, not just as it exists now but as it existed in the past. It's fun for me to think of the museum collection sort of like the voice of those long dead organisms that are still telling us something about the state of the world today."

"You can't do this kind of work without these collections," says McMahan. "We need older specimens, we need the recent ones, and we're going to need what we collect in the next 100 years."

Boulder, Colo., USA: Thirty-one new articles were published online ahead of
print for Geology in April. Topics include shocked zircon from the
Chicxulub impact crater; the Holocene Sonoran Desert; the architecture of
the Congo Basin; the southern Death Valley fault; missing water from the
Qiangtang Basin; sulfide inclusions in diamonds; how Himalayan collision
stems from subduction; ghost dune hollows; and the history of the Larsen C Ice Shelf. These Geology articles are online at

https://geology.geoscienceworld.org/content/early/recent

.

Nonlinear fault damage zone scaling revealed through analog modeling

Sylvain Mayolle; Roger Soliva; Stéphane Dominguez; Christopher Wibberley;
Yannick Caniven

Abstract:
Fault damage zones strongly influence fluid flow and seismogenic behavior
of faults and are thought to scale linearly with fault displacement until
reaching a threshold thickness. Using analog modeling with different
frictional layer thicknesses, we investigate damage zone dynamic evolution
during normal fault growth. We show that experimental damage zone growth
with displacement is not linear but progressively tends toward a threshold
thickness, being larger in the thicker models. This threshold thickness
increases significantly at fault segment relay zones. As the thickness
threshold is approached, the failure mode progressively transitions from
dilational shear to isochoric shear. This process affects the whole layer
thickness and develops as a consequence of fault segment linkage as
inferred in nature when the fault matures. These findings suggest that
fault damage zone widths are limited both by different scales of mechanical
unit thickness and the evolution of failure modes, ultimately controlled in
nature by lithology and deformation conditions.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48760.1/596503/Nonlinear-fault-damage-zone-scaling-revealed

History of the Larsen C Ice Shelf

reconstructed from sub–ice shelf and offshore sediments

J.A. Smith; C.-D. Hillenbrand; C. Subt; B.E. Rosenheim; T. Frederichs ...

Abstract:
Because ice shelves respond to climatic forcing over a range of time
scales, from years to millennia, an understanding of their long-term
history is critically needed for predicting their future evolution. We
present the first detailed reconstruction of the Larsen C Ice Shelf (LCIS),
eastern Antarctic Peninsula (AP), based on data from sediment cores
recovered from below and in front of the ice shelf. Sedimentologic and
chronologic information reveals that the grounding line (GL) of an expanded
AP ice sheet had started its retreat from the midshelf prior to 17.7 ± 0.53
calibrated (cal.) kyr B.P., with the calving line following ~6 k.y. later.
The GL had reached the inner shelf as early as 9.83 ± 0.85 cal. kyr B.P.
Since ca. 7.3 ka, the ice shelf has undergone two phases of retreat but
without collapse, indicating that the climatic limit of LCIS stability was
not breached during the Holocene. Future collapse of the LCIS would
therefore confirm that the magnitudes of both ice loss along the eastern AP
and underlying climatic forcing are unprecedented during the past 11.5 k.y.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48503.1/596504/History-of-the-Larsen-C-Ice-Shelf-reconstructed

Confirmation of slow Ti diffusion in quartz by diffusion couple
experiments and evidence from natural samples

Andreas Audétat; Nobuyoshi Miyajima; Dorothea Wiesner; Jean-Nicolas Audinot

Abstract:
Titanium diffusion profiles in natural quartz crystals have become an
increasingly popular tool to reconstruct the time scales of various
magmatic, metamorphic, and hydrothermal processes. However, the original
calibration of Ti diffusion rates in quartz has recently been challenged,
and diffusivities were found to be about three orders of magnitude lower.
We performed annealing experiments on crystal-crystal diffusion couples
consisting of Ti-free synthetic quartz seeds over which Ti-rich quartz
(100–3000 μg/g Ti) was grown hydrothermally. The annealing experiments were
performed at 1000–1600 °C and 0.1 MPa to 2.0 GPa, and they lasted for 3–84
days. The resulting diffusion profiles were mapped by cathodoluminescence
(CL), transmission electron microscope–energy-dispersive X-ray spectroscopy
(TEM-EDXS), and, for the first time, by helium ion microscope–secondary ion
mass spectrometry (HIM-SIMS). Obtained diffusion coefficients range from
values similar to the lower range in previous research to values up to two
orders of magnitude lower. In addition, inversely zoned quartz and sanidine
phenocrysts in a natural rhyolite were studied. Comparison of the diffusion
profiles suggests that at ~735 °C, the Ti diffusivity in quartz is ~1.5 and
3.0 orders of magnitude lower than that of Ba and Sr, respectively, in
sanidine. The combined evidence confirms that Ti diffusion in quartz is
very slow, potentially even slower than proposed earlier. Consequently,
previous time scales derived from Ti diffusion profiles in quartz are
likely orders of magnitude too short, and further experiments are necessary
to fully clarify the issue.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48785.1/596505/Confirmation-of-slow-Ti-diffusion-in-quartz-by

Did accretion of the Caribbean oceanic plateau drive rapid crustal
thickening in the northern Andes?

Sarah W.M. George; Brian K. Horton; Cristian Vallejo; Lily J. Jackson; E.
Gabriela Gutierrez

Abstract:
The onset of orogenic shortening in the northern Andes Mountains coincided
with latest Cretaceous accretion of the Caribbean oceanic plateau. We
present isotopic data (εHf in zircon and εNd) coupled with arc position to
test whether accretion led to abrupt crustal thickening in the northern
Andes of Ecuador and Colombia. A rapid isotopic excursion toward more
evolved crustal compositions was synchronous with ca. 75–70 Ma collision in
Ecuador and preceded a similar deviation in Colombia at ca. 70–55 Ma. The
rapid but diachronous shift to more evolved isotopic signatures is
attributed to progressive northward accretion of the oceanic plateau and
associated thickening of continental crust. We emphasize the effects of
accretion on the magmatic evolution of Cordilleran-type margins, initially
provoking shortening and crustal thickening, and ultimately providing a
substrate for subsequent arcs.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48509.1/596506/Did-accretion-of-the-Caribbean-oceanic-plateau

How Himalayan collision stems from subduction

M. Soret; K.P. Larson; J. Cottle; A. Ali

Abstract:
The mechanisms and processes active during the transition from continental
subduction to continental collision at the plate interface are largely
unknown. Rock records of this transition are scarce, either not exposed or
obliterated during subsequent events. We examine the tectono-metamorphic
history of Barrovian metamorphic rocks from the western Himalayan orogenic
wedge. We demonstrate that these rocks were buried to amphibolite-facies
conditions from ≤47 Ma to 39 ± 1 Ma, synchronously with the formation (46
Ma) and partial exhumation (45–40 Ma) of the ultrahigh-pressure eclogites.
This association indicates that convergence during continental subduction
was accommodated via development of a deep orogenic wedge built through
successive underplating of continental material, including the partially
exhumed eclogites, likely in response to an increase in interplate
coupling. This process resulted in the heating of the subduction interface
(from ~7 to ~20 °C/km) through advective and/or conductive heat transfer.
Rapid cooling of the wedge from 38 Ma, coeval with the formation of a
foreland basin, are interpreted to result from indentation of a promontory
of thick Indian crust.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48803.1/596507/How-Himalayan-collision-stems-from-subduction

Mud in sandy riverbed deposits as a proxy for ancient fine-sediment
supply

N. Wysocki; E. Hajek

Abstract:
The amount of silt and clay available to rivers reflects source-terrain
composition and weathering and can be a primary control on the form and
dynamics of channel networks. Fine sediment also affects the permeability
of buried fluvial reservoirs. Despite this significance, there is currently
a lack of methods for reconstructing how much fine sediment was transported
by ancient rivers. Mud accumulations in sandy river deposits are often
interpreted as indicators of variable flow conditions; however, these
deposits may present an opportunity to constrain how much fine sediment was
transported through ancient rivers. We report results from a series of
experiments designed to evaluate how much clay and silt are preserved in
sandy riverbed deposits under constant and variable discharge conditions.
Our results demonstrate that (1) mud deposits, including drapes and lenses,
form readily under constant, high-discharge conditions, (2) the amount of
fine sediment recovered from bed-material deposits increases as
fine-sediment supply increases, and (3) fine-sediment retention is higher
during bed aggradation than during bypass conditions. These results
indicate that the net retention of clay and silt in sandy riverbed deposits
may be a simple but powerful proxy for comparing the overall amount of fine
sediment supplied to ancient rivers.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48251.1/596508/Mud-in-sandy-riverbed-deposits-as-a-proxy-for

Subduction of the Izanagi-Pacific Ridge–transform intersection at the
northeastern end of the Eurasian plate

Toru Yamasaki; Gen Shimoda; Kenichiro Tani; Jinichiro Maeda; Futoshi
Nanayama

Abstract:
Recent reconstructions of global plate motions suggest that the
Izanagi-Pacific Ridge was subducted along the eastern margin of Eurasia at
ca. 50 Ma. In the Hidaka magmatic zone (HMZ), which was located at the
northeastern end of the Eurasian plate, three magmatic pulses occurred
(46–45, 40–36, and 19–18 Ma). We report whole-rock geochemical and Sr-Nd-Pb
isotopic data for 36 Ma high-Sr/Y (adakitic) rocks from the HMZ and show
that these rocks formed by partial melting of oceanic crust and were
emplaced as near-trench intrusions during ridge subduction. We reevaluate
the nature of plutonic rocks in the HMZ and show that both the 46–45 and
40–36 Ma granitoids have essentially identical geochemical features. The
distribution of plutons and magmatic cessation between 45 and 40 Ma are
best explained by subduction of a ridge-transform intersection with a large
offset of the ridge axis. The boundary between the Eocene granitoids
corresponds to the position of a paleo–transform fault, and adakitic
magmatism was caused by partial melting triggered by slab tearing at an
overlapping spreading center. The paleoridge-transform configuration
coincides with the locations of later large faults and a peridotite body.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48611.1/596509/Subduction-of-the-Izanagi-Pacific-Ridge-transform

Climatically driven instability of marine methane hydrate along a
canyon-incised continental margin

Richard J. Davies; Miguel Ángel Morales Maqueda; Ang Li; Mark Ireland

Abstract:
Establishing how past climate change affected the stability of marine
methane hydrate is important for our understanding of the impact of a
future warmer world. As oceans shallow toward continental margins, the base
of the hydrate stability zone also shallows, and this delineates the
feather edge of marine methane hydrate. It is in these rarely documented
settings that the base of the hydrate stability zone intersects the seabed
and hydrate can crop out where it is close to being unstable and most
susceptible to dissociation due to ocean warming. We show evidence for a
seismically defined outcrop zone intersecting canyons on a canyon-incised
margin offshore of Mauritania. We propose that climatic, and hence ocean,
warming since the Last Glacial Maximum as well as lateral canyon migration,
cutting, and filling caused multiple shifts of the hydrate stability field,
and therefore hydrate instability and likely methane release into the
ocean. This is particularly significant because the outcrop zone is longer
on canyon-incised margins than on less bathymetrically complex submarine
slopes. We propose considerably more hydrate will dissociate in these
settings during future ocean warming, releasing methane into the world’s
oceans.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48638.1/596510/Climatically-driven-instability-of-marine-methane

Enhanced Quaternary exhumation in the Namche Barwa syntaxis, eastern
Himalaya

Rong Yang; Frédéric Herman; Ting Liu; Rabiul Haque Biswas; Maria Giuditta
Fellin ...

Abstract:
The Namche Barwa syntaxis in the eastern Himalaya is rapidly evolving in
terms of its tectonics and topography. Here we constrain the exhumation
history of the Yigong River to the immediate north of the syntaxis across
different time scales using a multidisciplinary approach. Our new
thermochronometric data reveal an acceleration of exhumation rates since 2
Ma in the downstream of the Yigong. Cosmogenic nuclides and
thermoluminescence thermochronometry analyses confirm persistent rapid
exhumation in the lower Yigong over the Quaternary with further increased
exhumation in the last 100 ka. Together with the analysis of the morphology
of the Yigong River profile, we interpret that northward expansion of the
syntaxis together with capture of the Yigong by the Yarlung Tsangpo River
during this expansion is responsible for the exhumation history of the
Yigong River in the Quaternary.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48595.1/596325/Enhanced-Quaternary-exhumation-in-the-Namche-Barwa

Protogenetic sulfide inclusions in diamonds date the diamond formation
event using Re-Os isotopes

M.G. Pamato; D. Novella; D.E. Jacob; B. Oliveira; D.G. Pearson ...

Abstract:
Sulfides are the most abundant inclusions in diamonds and a key tool for
dating diamond formation via Re-Os isotopic analyses. The manner in which
fluids invade the continental lithospheric mantle and the time scale at
which they equilibrate with preexisting (protogenetic) sulfides are poorly
understood yet essential factors to understanding diamond formation and the
validity of isotopic ages. We investigated a suite of sulfide-bearing
diamonds from two Canadian cratons to test the robustness of Re-Os in
sulfide for dating diamond formation. Single-crystal X-ray diffraction
(XRD) allowed determination of the original monosulfide solid-solution
(Mss) composition stable in the mantle, indicating subsolidus conditions of
encapsulation, and providing crystallographic evidence supporting a
protogenetic origin of the inclusions. The results, coupled with a
diffusion model, indicate Re-Os isotope equilibration is sufficiently fast
in sulfide inclusions with typical grain size, at mantle temperatures, for
the system to be reset by the diamond-forming event. This confirms that
even if protogenetic, the Re-Os isochrons defined by these minerals likely
reflect the ages of diamond formation, and this result highlights the power
of this system to date the timing of fluid migration in mantle lithosphere.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48651.1/596326/Protogenetic-sulfide-inclusions-in-diamonds-date

New statistical quantification of the impact of active deformation on
the distribution of submarine channels

Marco Pizzi; Alexander C. Whittaker; Lidia Lonergan; Mike Mayall; W. Hamish
Mitchell

Abstract:
Submarine channel systems play a crucial role in governing the delivery of
sediments and pollutants such as plastics from the shelf edge to deep
water. Understanding their distribution in space and time is important for
constraining the locus, magnitude, and characteristics of deep-water
sedimentation and for predicting stratigraphic architectures and
depositional facies. Using three-dimensional seismic reflection data
covering the outer fold-and-thrust belt of the Niger Delta, we determined
the pathways of Miocene to Pliocene channels that crossed, at 173
locations, 11 fold-thrust structures for which the temporal and spatial
evolution of strain rates has been constrained over a period of 11 m.y. We
use a statistical approach to quantify strain and shortening rate
distributions recorded where channels have crossed structures compared to
the fault array as a whole. Our results prove unambiguously that these
distributions are different. The median strain rate where channels cross
faults is <0.6%/m.y. (~40 m/m.y.), 2.5× lower than the median strain
rate of active fault segments (1.5%/m.y.) with a marked reduction in the
number of channel-fault crossings where fault strain rates are >1%/m.y.
Our results quantify the sensitivity of submarine channels to active
deformation at a population level for the first time and enable us to
predict the temporal and spatial routing of submarine channels affected by
structurally driven topography.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48698.1/596327/New-statistical-quantification-of-the-impact-of

Paleozoic evolution of crustal thickness and elevation in the northern
Appalachian orogen, USA

Ian W. Hillenbrand; Michael L. Williams

Abstract:
The Acadian and Neoacadian orogenies are widely recognized, yet poorly
understood, tectono-thermal events in the New England Appalachian Mountains
(USA). We quantified two phases of Paleozoic crustal thickening using
geochemical proxies. Acadian (425–400 Ma) crustal thickening to 40 km
progressed from southeast to northwest. Neoacadian (400–380 Ma) crustal
thickening was widely distributed and varied by 30 km (40–70 km) from north
to south. Doubly thickened crust and paleoelevations of 5 km or more
support the presence of an orogenic plateau at ca. 380–330 Ma in southern
New England. Neoacadian crustal thicknesses show a strong correlation with
metamorphic isograds, where higher metamorphic grade corresponds to greater
paleo-crustal thickness. We suggest that the present metamorphic field
gradient was exposed through erosion and orogenic collapse influenced by
thermal, isostatic, and gravitational properties related to Neoacadian
crustal thickness. Geobarometry in southern New England underestimates
crustal thickness and exhumation, suggesting the crust was thinned by
tectonic as well as erosional processes.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48705.1/596328/Paleozoic-evolution-of-crustal-thickness-and

Diapiric relamination of the Orocopia Schist (southwestern U.S.) during
low-angle subduction

James B. Chapman

Abstract:
The Orocopia Schist and related schists are sediments subducted during the
Laramide orogeny and are thought to have been underplated as a laterally
extensive layer at the base of the crust in the southwestern United States
Cordillera. This concept is hard to reconcile with the existence of
continental mantle lithosphere in southeastern California and western
Arizona. Analytical solutions and numerical modeling suggest that the
Orocopia Schist may have ascended through the mantle lithosphere as
sediment diapirs or subsolidus crustal plumes to become emplaced in the
middle to lower crust. Modeled time-temperature cooling paths are
consistent with the exhumation history of the Orocopia Schist and explain
an initial period of rapid cooling shortly after peak metamorphism. The
Orocopia Schist represents a potential example of relaminated sediment
observable at the surface.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48647.1/596330/Diapiric-relamination-of-the-Orocopia-Schist

Annually resolved sediments in the classic Clarkia lacustrine deposits
(Idaho, USA) during the middle Miocene Climate Optimum

Daianne Höfig; Yi Ge Zhang; Liviu Giosan; Qin Leng; Jiaqi Liang ...

Abstract:
The world-renowned Miocene Clarkia paleolake in northern Idaho (USA) is
closely associated with Columbia River Basalt Group volcanism. The flood
basalt dammed a local drainage system to form the paleolake, which
preserved a plant fossil Lagerstätte in its deposits. However, the
precise age and temporal duration of the lake remain unsettled. We present
the first unequivocal U-Pb zircon ages from interbedded volcanic ashes at
the P-33 type location, constraining the deposition to 15.78 ± 0.039 Ma.
Using micro–X-ray fluorescence and petrographic and spectral analyses, we
establish the annual characteristics of laminations throughout the
stratigraphic profile using the distribution of elemental ratios, mineral
assemblages, and grain-size structures, as well as organic and fossil
contents. Consequently, the ~7.5-m-thick varved deposit at the type
location P-33 represents ~840 yr of deposition, coincident with the end of
the main phase of Columbia River Basalt Group eruptions during the Miocene
Climate Optimum. The timing and temporal resolution of the deposit offer a
unique opportunity to study climate change in unprecedented detail during
global warming associated with carbon-cycle perturbations.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48901.1/596161/Annually-resolved-sediments-in-the-classic-Clarkia

The carbonate compensation depth in the South Atlantic Ocean since the
Late Cretaceous

Adriana Dutkiewicz; R. Dietmar Müller

Abstract:
Deep-sea carbonate deposition is a complex process that is encapsulated in
the carbonate compensation depth (CCD)—a facies boundary separating
calcareous sediments from non-carbonates. Knowing how the CCD has varied
over time is important for understanding and predicting the distribution of
seafloor sediments and assessing their role in the global carbon cycle. We
focus on the South Atlantic Ocean where the most recent CCD curve is based
on Deep Sea Drilling Project (DSDP) Leg 73 sites drilled in 1980 in the
South Atlantic Ocean. We compute the South and central South Atlantic CCD
from the Late Cretaceous to the present day using updated age models from
45 DSDP and Ocean Drilling Program sites and backtracking with
lithology-specific decompaction, eustasy, and dynamic topography. Our
models extend further back in time and show more fluctuations than previous
reconstructions, with the CCD varying by hundreds of meters during a span
of 2–3 m.y. The addition of eustasy and dynamic topography deepens the CCD
by as much as 500 m between 74 Ma and 45 Ma, and by ~200 m during the
Cenozoic. The central South Atlantic CCD diverges from the average South
Atlantic CCD during the Eocene and Miocene, when it was ~1 km shallower.
These regional deviations may be due to changes in primary productivity
and/or carbonate dissolution leading to reduced carbonate accumulation
rates. Our CCD curves highlight the importance of regional processes in
carbonate deposition across the South Atlantic and provide improved
constraints for the modeling of geochemical cycles.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48404.1/596162/The-carbonate-compensation-depth-in-the-South

Transient Permian-Triassic euxinia in the southern Panthalassa deep
ocean

S.E. Grasby; D.P.G. Bond; P.B. Wignall; R. Yin; L.J. Strachan ...

Abstract:
Both the duration and severity of deep-water anoxic conditions across the
Permian-Triassic mass extinction (PTME) are controversial. Panthalassa
Ocean circulation models yield varying results, ranging from a
well-ventilated deep ocean to rapidly developing northern-latitude, but not
southern-latitude, anoxia in response to Siberian Traps–driven global
warming. To address this uncertainty, we examined a southern-paleolatitude
pelagic record. Trace metal and pyrite framboid data suggest bottom-water
euxinic conditions developed in the southern Panthalassa Ocean at the PTME,
coincident with enhanced volcanic activity indicated by Hg geochemistry.
While a global ocean euxinic event at the PTME placed extraordinary stress
on marine life, southern surface waters appear to have recovered more
quickly as radiolarian populations returned several million years before
they did in northern Panthalassa.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48928.1/596163/Transient-Permian-Triassic-euxinia-in-the-southern

Water transfer to the deep mantle through hydrous, Al-rich silicates in
subduction zones

Jörg Hermann; Shayne Lakey

Abstract:
Constraining deep-water recycling along subduction zones is a first-order
problem to understand how Earth has maintained a hydrosphere over billions
of years that created conditions for a habitable planet. The
pressure-temperature stability of hydrous phases in conjunction with slab
geotherms determines how much H2O leaves the slab or is
transported to the deep mantle. Chlorite-rich, metasomatic rocks that form
at the slab-mantle interface at 50–100 km depth represent an unaccounted, H 2O-rich reservoir in subduction processes. Through a series of
high-pressure experiments, we investigated the fate of such chlorite-rich
rocks at the most critical conditions for subduction water recycling (5–6.2
GPa, 620–800 °C) using two different natural ultramafic compositions. Up to
5.7 GPa, 740 °C, chlorite breaks down to an anhydrous peridotite
assemblage, and H2O is released. However, at higher pressures
and lower temperatures, a hydrous Al-rich silicate (11.5 Å phase) is an
important carrier to enable water transfer to the deep mantle for cold
subduction zones. Based on the new phase diagrams, it is suggested that the
deep-water cycle might not be in secular equilibrium.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G48658.1/596165/Water-transfer-to-the-deep-mantle-through-hydrous

Eruption risks from covert silicic magma bodies

Shane M. Rooyakkers; John Stix; Kim Berlo; Maurizio Petrelli; Freysteinn
Sigmundsson

Abstract:
Unintentional encounters with silicic magma at ~2–2.5 km depth have
recently occurred during drilling at three volcanoes: Kilauea (Hawaii),
Menengai (Kenya), and Krafla (Iceland). Geophysical surveys had failed to
warn about shallow magma before each encounter, and subsequent surveys at
Krafla have been unable to resolve the size or architecture of its silicic
magma body. This presents a conundrum for volcano monitoring: Do such
shallow “covert” magma bodies pose an eruption risk? Here, we show that
Krafla’s most recent explosive eruption, a mixed hydrothermal-magmatic
event in 1724 C.E. that formed the Víti maar, involved rhyolite essentially
indistinguishable in composition from magma encountered during drilling in
2009. Streaks of quenched basalt in some Víti pumices provide direct
evidence for interaction between co-erupted rhyolitic and basaltic magmas,
but crystals in these pumices show no evidence for late-stage heating or
re-equilibration with more mafic melt, implying mixing time scales of at
most several hours. Covert silicic magma thus presents an eruption risk at
Krafla and may be mobilized with little warning. Difficulties in resolving
magma bodies smaller than ~1 km3 with geophysical surveys mean
that covert silicic magma may exist at many other volcanoes and should be
considered in hazard and risk assessments.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48697.1/596166/Eruption-risks-from-covert-silicic-magma-bodies

Ghost-dune hollows of the eastern Snake River Plain, Idaho: Their
genesis, evolution, and relevance to Martian ghost-dune pits

David R. Gaylord; Tammy M. Rittenour; Paul K. Link; Brent D. Turrin; Mel A.
Kuntz

Abstract:
Ghost-dune hollows on the eastern Snake River Plain (ESRP), Idaho, USA, are
topographically inverted, crescent-shaped depressions that record the
partial encasement of sand dunes by ca. 61 ka basalt lava flows. Deflation
of these “ghost” sand dunes produced approximately two dozen, 5–10-m-deep
ghost-dune hollows now incompletely filled with pedogenically altered
eolian and colluvial sediment. Optically stimulated luminescence (OSL) and 40Ar/39Ar ages constrain a ghost-dune hollow model
that illuminates the late Pleistocene to Holocene environmental and climate
history of the ESRP. Detrital zircon analyses indicate sand-dune supply
routes changed following the burial of Pleistocene Henrys Fork (tributary
of the Snake River) alluvium by ca. 70 ka basalt flows. Removal of Henrys
Fork alluvium from the eolian supply system made Lake Terreton sediment the
primary source for later ESRP sand dunes. Such sediment supply changes
highlight the potential impacts of effusive volcanism on sand-dune
histories and landscapes. Our results support stratigraphic and sedimentary
modeling of comparable ghost-dune “pit” deposits older than ca. 2 Ga on
Mars that may have served as refugia for early life on that planet.
Analogous ancient ghost-dune hollow deposits on Earth may also have served
as early life refugia.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48645.1/596167/Ghost-dune-hollows-of-the-eastern-Snake-River

Controls on the origin and evolution of deep-ocean trench-axial
channels

Adam D. McArthur; Daniel E. Tek

Abstract:
The type and volume of sediment entering subduction zones affects the style
of plate-boundary deformation and thus sedimentary and tectonic cycles.
Because submarine channels significantly increase the transport efficiency
of turbidity currents, their presence or absence in subduction trenches is
a primary control on trench fill. To date, comprehensive architectural
characterization of trench-axial channels has not been possible,
undermining efforts to identify the factors controlling their initiation
and evolution. Here, we describe the evolution of the Hikurangi Channel,
which traverses the Hikurangi Trench, offshore New Zealand. Analysis of
two- and three-dimensional seismic data reveals that the channel was
present only during the last ~3.5 m.y. of the ~27 m.y. of the trench’s
existence; its inception and propagation resulted from increased sediment
supply to the trench following amplified hinterland exhumation. To test if
the controls on the evolution of the Hikurangi Channel are universal,
multivariate statistical analysis of the geomorphology of subduction
trenches globally is used to investigate the formative conditions of axial
channels in modern trenches. Terrigenous sediment supply and thickness of
sediment cover in a trench are the dominant controls; subsidiary factors
such as trench length and rugosity also contribute to the conditions
necessary for trench-axial channel development. Axial channels regulate
sediment distribution in trenches, and this varies temporally and spatially
as a channel propagates along a trench. The presence of a trench-axial
channel affects plate-boundary mechanics and has implications for the style
of subduction-margin deformation.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48612.1/596024/Controls-on-the-origin-and-evolution-of-deep-ocean

Joint inversion of surface wave and gravity data reveals subbasin
architecture of the Congo Basin

A. Raveloson; A. Nyblade; R. Durrheim

Abstract:
We investigated the architecture of the greater Congo Basin, one of the
largest and least-well-studied sedimentary basins on any continent.
Seismograms from a large number of M > 4.5 earthquakes within and
surrounding the African plate were used to make event-to-station Rayleigh
wave group velocity measurements between periods of 5 and 100 s. Group
velocities for discrete periods across the basin, obtained by inverting the
event-station measurements, were jointly modeled with gravity data to
obtain a three-dimensional S-wave and density model of the basin. The model
corroborates the existence of two previously suggested subbasins, one to
the north and one to the south, each ~8 km deep and separated by an
east-west structural high. Our results favor a salt tectonics origin for
the structural high but cannot rule out uplifted basement rock. The
northern subbasin is offset to the west from the southern subbasin,
consistent with previous studies suggesting sinistral motion along basement
faults during periods of transpressional tectonics in late
Neoproterozoic–early Paleozoic times.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48408.1/596025/Joint-inversion-of-surface-wave-and-gravity-data

Hydrothermal recycling of sedimentary ammonium into oceanic crust and
the Archean ocean at 3.24 Ga

E.E. Stüeken; T.J. Boocock; A. Robinson; S. Mikhail; B.W. Johnson

Abstract:
The Archean ocean supported a diverse microbial ecosystem, yet studies
suggest that seawater was largely depleted in many essential nutrients,
including fixed nitrogen. This depletion was in part a consequence of
inefficient nutrient recycling under anoxic conditions. Here, we show how
hydrothermal fluids acted as a recycling mechanism for ammonium (NH 4+) in the Archean ocean. We present elemental and
stable isotope data for carbon, nitrogen, and sulfur from shales and
hydrothermally altered volcanic rocks from the 3.24 Ga Panorama district in
Western Australia. This suite documents the transfer of NH4 + from organic-rich sedimentary rocks into underlying
sericitized dacite, similar to what is seen in hydrothermal systems today.
On modern Earth, hydrothermal fluids that circulate through sediment
packages are enriched in NH4+ to millimolar
concentrations because they efficiently recycle organic-bound N. Our data
show that a similar hydrothermal recycling process dates back to at least
3.24 Ga, and it may have resulted in localized centers of enhanced
biological productivity around hydrothermal vents. Last, our data provide
evidence that altered oceanic crust at 3.24 Ga was enriched in nitrogen,
and, when subducted, it satisfies the elemental and isotopic source
requirements for a low-N, but 15N-enriched, deep mantle nitrogen
reservoir as sampled by mantle plumes.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48844.1/596026/Hydrothermal-recycling-of-sedimentary-ammonium

Missing water from the Qiangtang Basin on the Tibetan Plateau

Bin Yong; Chi-Yuen Wang; Jiansheng Chen; Jiaqi Chen; D.A. Barry ...

Abstract:
The Qiangtang Basin is a large endorheic basin in the inner part of the
Tibetan Plateau, and has been thought to be a dry region in contrast with
the surrounding wet outer region that feeds all the major Asian rivers.
Combining surface hydrological data with modeling and satellite data from
2002 to 2016 CE, our study reveals that an enormous amount of water, ~54 ±
4 km3, is unaccounted for annually in the Qiangtang Basin. The
amount of missing water is comparable to the total annual discharge of the
Yellow River. Data from the Gravity Recovery and Climate Experiment (GRACE)
satellite mission show little increase of local terrestrial water storage.
Thus, the missing water must have flowed out of the basin through
underground passages. Interpreting this result in the context of recent
seismic and geological studies of Tibet, we suggest that a significant
amount of meteoric water in the Qiangtang Basin leaks out by way of
groundwater flow through deep normal faults and tensional fractures along
the nearly north-south rift valleys that are oriented subnormal to and
cross the surficial hydrological divide on the southern margin of the
basin. Cross-basin groundwater outflow of such a magnitude defies the
traditional view of a basin-scale water cycle and leads to a very different
picture from the previous hydrological view of the Qiangtang Basin. This
finding calls for major rethinking of the regional water balance.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48561.1/596027/Missing-water-from-the-Qiangtang-Basin-on-the

Alternating wet and dry depositional environments recorded in the
stratigraphy of Mount Sharp at Gale crater, Mars

W. Rapin; G. Dromart; D. Rubin; L. Le Deit; N. Mangold ...

Abstract:
The Curiosity rover is exploring Hesperian-aged stratigraphy in Gale
crater, Mars, where a transition from clay-bearing units to a layered
sulfate-bearing unit has been interpreted to represent a major
environmental transition of unknown character. We present the first
description of key facies in the sulfate-bearing unit, recently observed in
the distance by the rover, and propose a model for changes in depositional
environments. Our results indicate a transition from lacustrine mudstones
into thick aeolian deposits, topped by a major deflation surface, above
which strata show architectures likely diagnostic of a subaqueous
environment. This model offers a reference example of a depositional
sequence for layered sulfate-bearing strata, which have been identified
from orbit in other locations globally. It differs from the idea of a
monotonic Hesperian climate change into long-term aridity on Mars and
instead implies a period characterized by multiple transitions between
sustained drier and wetter climates.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48519.1/596028/Alternating-wet-and-dry-depositional-environments

Evidence for 40–41 km of dextral slip on the southern Death Valley
fault: Implications for the Eastern California shear zone and
extensional tectonics

Terry L. Pavlis; Ghislain Trullenque

Abstract:
Recognition of a pair of pre-Neogene markers together with analysis of
published data indicate ~40 km of dextral slip across the southern Death
Valley fault zone, California, USA. Stratigraphic overlaps on fault rocks
indicate much of the dextral slip predates the late Miocene, placing a
significant fraction of the dextral slip in the same time window as
regional extension and challenging interpretations that the modern
strike-slip system became active post–6–3 Ma. However, these results are
consistent with regional evidence that dextral transtension began by ca. 12
Ma.

View article:
https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48528.1/596029/Evidence-for-40-41-km-of-dextral-slip-on-the

A metasedimentary source of gold in Archean orogenic gold deposits

Iain K. Pitcairn; Nikolaos Leventis; Georges Beaudoin; Stephane Faure; Carl
Guilmette ...

Abstract:
The sources of metals enriched in Archean orogenic gold deposits have long
been debated. Metasedimentary rocks, which are generally accepted as the
main metal source in Phanerozoic deposits, are less abundant in Archean
greenstone belts and commonly discounted as a viable metal source for
Archean deposits. We report ultralow-detection-limit gold and trace-element
concentrations from a suite of metamorphosed sedimentary rocks from the
Abitibi belt and Pontiac subprovince, Superior Province, Canada. Systematic
decreases in the Au content with increasing metamorphic grade indicate that
Au was mobilized during prograde metamorphism. Mass balance calculations
show that over 10 t of Au, 30,000 t of As, and 600 t of Sb were mobilized
from 1 km3 of Pontiac subprovince sedimentary rock metamorphosed
to the sillimanite metamorphic zone. The total gold resource in orogenic
gold deposits in the southern Abitibi belt (7500 t Au) is only 3% of the Au
mobilized from the estimated total volume of high-metamorphic-grade Pontiac
sedimentary rock in the region (25,000 km3), indicating that
sedimentary rocks are a major contributor of metals to the orogenic gold
deposits in the southern Abitibi belt.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48587.1/596030/A-metasedimentary-source-of-gold-in-Archean

Similar curvature-to-width ratios for channels and channel belts:
Implications for paleo-hydraulics of fluvial ridges on Mars

Alistair T. Hayden; Michael P. Lamb; Alexander J. Carney

Abstract:
The surface of Mars contains abundant sinuous ridges that appear similar to
river channels in planform, but they stand as topographic highs. Ridges
have similar curvature-to-width ratios as terrestrial meandering rivers,
which has been used to support the hypothesis that ridges are inverted
channels that directly reflect channel geometry. Anomalously wide ridges,
in turn, have been interpreted as evidence for larger rivers on Mars
compared to Earth. However, an alternate hypothesis is that ridges are
exhumed channel-belt deposits—a larger zone of relatively coarse-grained
deposits formed from channel lateral migration and aggradation. Here, we
measured landform wavelength, radius of curvature, and width to compare
terrestrial channels, terrestrial channel belts, and martian ridges. We
found that all three landforms follow similar scaling relations, in which
ratios of radius of curvature to width range from 1.7 to 7.3, and
wavelength-to-width ratios range from 5.8 to 13. We interpret this
similarity to be a geometric consequence of a sinuous curved line of finite
width. Combined with observations of ridge-stacking patterns, our results
suggest that wide ridges on Mars could indicate fluvial channel belts that
formed over significant time rather than anomalously large rivers.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48370.1/595962/Similar-curvature-to-width-ratios-for-channels-and

Outer forearc uplift and exhumation during high-flux magmatism:
Evidence from detrital zircon geochemistry of the Nacimiento forearc
basin, California, USA

Scott M. Johnston; Andrew R.C. Kylander-Clark

Abstract:
We present new coupled detrital zircon trace-element and U–Pb age data from
Valanginian–Santonian strata of the Nacimiento forearc basin (California,
USA) to enhance provenance discrimination and investigate the evolution of
the late Mesozoic California margin. Our data document at least five
different Jurassic–earliest Cretaceous zircon populations with variable
U/Yb ratios, and zircon that displays systematically increasing U/Yb from
130 to 80 Ma. Based on the presence of a distinctive population of
geochemically primitive, 168–157 Ma low-U/Yb zircon that is found in
Albian–Lower Cenomanian strata but not in older Valanginian strata, we
infer a period of uplift and Albian–early Cenomanian erosion of forearc
basement (the Coast Range ophiolite) that was coincident with increasing
Cordilleran arc magmatic flux.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48627.1/595963/Outer-forearc-uplift-and-exhumation-during-high

Shutting down dust emission during the middle Holocene drought in the
Sonoran Desert, Arizona, USA

Guy Tau; Onn Crouvi; Yehouda Enzel; Nadya Teutsch; Paul Ginoux ...

Abstract:
Long-term relationships between climate and dust emission remain unclear,
with two prevailing but opposite hypotheses for effects of climate shifts:
(1) increased dust emission due to increasing aridity imposing a vegetation
change, or (2) decreased dust emission due to increasing aridity which
imposes less stormy climate and reduced sediment supply. Here we test these
hypotheses by analyzing an ~11-m-long core archiving Holocene dust trapped
in Montezuma Well, a natural sinkhole in Arizona (southwestern United
States), alongside current dust sources and transport pathways. Major
elements indicate that Montezuma Well sediments originate from two end
members: local carbonate bedrock and external siliceous dust. Core
sediments are similar to the adjacent siliceous soils accumulated atop the
bedrock, pointing to their eolian origin. Particle-size distributions
reveal fine dust transported during winter from the northwestern Sonoran
Desert and the Mojave Desert and coarse dust transported during summer from
the southwestern Sonoran Desert, similar to current climate systems and
dust pathways. A survey of potential dust sources indicates that current
summer and winter dust sources in the Sonoran Desert are under a
supply-limited state. Dust fluxes were higher during wetter phases of the
Holocene when winter sources dominated. During the middle Holocene drought,
dust fluxes were minimal and dominated by summer sources until dust input
ceased as drought conditions did not produce enough floods to refill
sources with sediments. We propose that in the Sonoran Desert, dust
emission is strongly connected with climate, increasing during humid
intervals and enhanced by fluvial sediment replenishment at dust sources.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48550.1/595964/Shutting-down-dust-emission-during-the-middle

Extensive decentralized hydrogen export from the Atlantis Massif

Susan Q. Lang; Marvin D. Lilley; Tamara Baumberger; Gretchen L. Früh-Green;
Sharon L. Walker ...

Abstract:
Hydrogen is an important energy source for subsurface microbial
communities, but its availability beyond the flow focused through
hydrothermal chimneys is largely unknown. We report the widespread export
of H2 across the Atlantis Massif oceanic core complex (30°N,
Mid-Atlantic Ridge; up to 44 nM), which is distinct from the
circulation system feeding the Lost City Hydrothermal Field (LCHF) on the
massif’s southern wall. Methane (CH4) abundances are generally
low to undetectable (<3 nM) in fluids that are not derived from
the LCHF. Reducing fluids exit the seafloor over a wide geographical area
and depth range, including the summit of the massif and along steep areas
of mass wasting east of the field. The depth of the fluids in the water
column and their H2/CH4 ratios indicate that some are
sourced separately from the LCHF. We argue that extensive H2
export is the natural consequence of fluid flow pathways strongly
influenced by tectonic features and the volume and density changes that
occur when ultramafic rocks react to form serpentinites, producing H 2 as a by-product. Furthermore, the circulation of H2
-rich fluids through uplifted mantle rocks at moderate temperatures
provides geographically expansive and stable environmental conditions for
the early evolution of biochemical pathways. These results provide insight
into the spatial extent of H2- and CH4-bearing fluids
associated with serpentinization, independent of the focused flow emanating
from the LCHF.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48322.1/595965/Extensive-decentralized-hydrogen-export-from-the

Shock-deformed zircon from the Chicxulub impact crater and implications
for cratering process

Jiawei Zhao; Long Xiao; Zhiyong Xiao; Joanna V. Morgan; Gordon R. Osinski
...

Abstract:
Large impact structures with peak rings are common landforms across the
solar system, and their formation has implications for both the interior
structure and thermal evolution of planetary bodies. Numerical modeling and
structural studies have been used to simulate and ground truth peak-ring
formative mechanisms, but the shock metamorphic record of minerals within
these structures remains to be ascertained. We investigated impact-related
microstructures and high-pressure phases in zircon from melt-bearing
breccias, impact melt rock, and granitoid basement from the Chicxulub peak
ring (Yucatán Peninsula, Mexico), sampled by the International Ocean
Discovery Program (IODP)/International Continental Drilling Project
(IODP-ICDP) Expedition 364 Hole M0077A. Zircon grains exhibit shock
features such as reidite, zircon twins, and granular zircon including
“former reidite in granular neoblastic” (FRIGN) zircon. These features
record an initial high-pressure shock wave (>30 GPa), subsequent
relaxation during the passage of the rarefaction wave, and a final heating
and annealing stage. Our observed grain-scale deformation history agrees
well with the stress fields predicted by the dynamic collapse model, as the
central uplift collapsed downward-then-outward to form the peak ring. The
occurrence of reidite in a large impact basin on Earth represents the first
such discovery, preserved due to its separation from impact melt and rapid
cooling by the resurging ocean. The coexistence of reidite and FRIGN zircon
within the impact melt–bearing breccias indicates that cooling by seawater
was heterogeneous. Our results provide valuable information on when
different shock microstructures form and how they are modified according to
their position in the impact structure, and this study further improves on
the use of shock barometry as a diagnostic tool in understanding the
cratering process.

View article:

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48278.1/595966/Shock-deformed-zircon-from-the-Chicxulub-impact

The genome of single-celled plankton, known as dinoflagellates, is organized in an incredibly strange and unusual way, according to new research. The findings lay the groundwork for further investigation into these important marine organisms and dramatically expand our picture of what a eukaryotic genome can look like.

Researchers from KAUST, the U.S. and Germany have investigated the genomic organization of the coral-symbiont dinoflagellate Symbiodinium microadriaticum. The S. microadriaticum genome had already been sequenced and assembled into segments known as scaffolds but lacked a chromosome-level assembly.

The team used a technique known as Hi-C to detect interactions in the dinoflagellate's chromatin, the combination of DNA and protein that makes up a chromosome. By analyzing these interactions, they could figure out how the scaffolds were connected together into chromosomes, giving them a view into the spatial and structural organization of the genome.

A striking finding was that the genes in the genome tended to be organized in alternating unidirectional blocks. "That's really, really different to what you see in other organisms," says Octavio Salazar, a Ph.D. student in Manuel Aranda's group at KAUST and one of the lead authors of the study. The orientation of genes on a chromosome is usually random. In this case, however, genes were consistently oriented one way and then the other, with the boundaries between blocks showing up clearly in the chromatin interaction data.

"Nature can work in a completely different way than we thought."

This organization is also reflected in the three-dimensional structure of the genome, which the team inferred comprises rod-shaped chromosomes that fold into structural domains at the boundaries where gene blocks converge. Even more intriguingly, this structure appears to be dependent on transcriptional activity. When the researchers treated cells with a chemical that blocks gene transcription, the structural domains disappeared.

This unusual link is consistent with another strange fact about dinoflagellates -- they have very few transcription factors in their genome and do not seem to respond to environmental changes by altering gene expression. They may use gene dosage to control expression and adapt to the environment by losing or gaining chromosomes or perhaps via epigenetic structural modifications. The researchers plan to explore all of these questions.

Another open question is the origin of this exceptional genome structure. Dinoflagellates produce very few histones, the proteins used by other eukaryotes to structure their DNA, instead using viral proteins incorporated into their genome long ago. The extraordinary genome structure and genetic regulation may be a consequence of how these viral proteins work, but that remains to be confirmed.

The dinoflagellate genome defies the expectation and dogmas built from studying other eukaryotes. "It shows that nature can work in a completely different way than we thought," says Salazar. "There are so many possibilities for what could have happened as life evolved."

DURHAM, N.C. - Mantis shrimp don't need baby food. They start their life as ferocious predators who know how to throw a lethal punch.

A new study appearing April 29 in the Journal of Experimental Biology shows that larvae of the Philippine mantis shrimp (Gonodactylaceus falcatus) already display the ultra-fast movements for which these animals are known, even when they are smaller than a short grain of rice.

Their ultra-fast punching appendages measure less than 1 mm, and develop right when the larva exhausts its yolk reserves, moves away from its nest and out into the big wide sea. It immediately begins preying on organisms smaller than a grain of sand.

Although they accelerate their arms almost 100 times faster than a Formula One car, Philippine mantis shrimp larvae are slower than larger adults, which goes against the theoretical expectation that smaller is always faster.

"They're producing amazing speeds and impressive accelerations relative to their body size, but they're not as fast as adults," said Jacob Harrison, a PhD candidate in biology at Duke University and lead author of the study.

Mantis shrimps achieve their ultra-fast movements through a tiny spring-actuated mechanism hidden in their punching appendage. A muscle contracts, deforming a tiny segment of their exoskeleton -the rigid cuticle that covers their body. This contraction allows elastic energy to be stored in the locked joint. Once the latch releases, the exoskeleton springs back into its natural position, violently propelling the appendage forward with ultra-fast speeds.

Engineering and physics models predict that smaller organisms, who have a smaller mass to displace, will be faster than larger, heavier, organisms. Mantis shrimp larvae show that biology doesn't always follow the theory.

"Theoretically, they should be producing the highest acceleration," said Harrison, "but we don't find that."

Harrison explains that this discrepancy may be due to multiple factors. The larvae muscles may be too small to effectively load a very stiff spring, or the water resistance at their small size may be too high for their punches to reach the speed that larger individuals reach, among other possibilities.

"There are limitations to these spring and latch structures that we don't fully understand," said Harrison. "But whenever biology moves away from theoretical models it highlights some pretty interesting areas for us to learn."

Mantis shrimp larvae are an interesting system not only due to their small size, but also due to their color, or lack thereof.

Adult mantis shrimps have opaque exoskeletons, rendering the inner working of their spring-latch mechanisms impossible to observe in action. The exoskeleton of larvae, however, is much thinner and fully transparent, allowing researchers to see precisely how these animals manage to store so much elastic energy in their tiny appendages simply by watching them through a microscope.

"One of the trickiest parts of researching spring-actuated mechanisms is that a lot of those elements are working inside the animal. We can look outside of the animal and see the behavior, measure the kinematics, dissect the animal, and say the mechanism looks like it works like this, but there are always levels of assumption," said Harrison.

"(Transparency) sets up larval mantis shrimps as systems where we can look at how each of these elements work in concert together," said Harrison. "It removes assumptions and allows us to understand it on a finer scale."

Larval mantis shrimps are therefore doubly interesting. They highlight discrepancies between physics and biology, and also offer a true window into a better understanding of the mechanism behind ultra-fast movements.

"When something doesn't match your predictions, the first gut reaction is always to be incredibly frustrated, but this is actually what highlights new areas of research," said Harrison.

In a novel effort to combat COVID-19 misinformation, a group of women researchers, including nurse scientists from the University of Pennsylvania School of Nursing (Penn Nursing), launched the Dear Pandemic social media campaign in March 2020. It delivers curated, comprehensive, and timely information about the COVID-19 pandemic in a question-and-answer format. Complex topics such as COVID-19 aerosol transmission, risk reduction strategies to avoid infection, and excess mortality are explained in common language and shared widely.

Now with more than 100,000 followers and accounts on Facebook, Twitter, and Instagram, the campaign has an international and multilingual impact offering important public health insight via social media. An article in the journal Public Health Nursing describes how the campaign is combating misinformation about COVID-19.

"Dear Pandemic has demonstrated that consistently publishing high-quality content outside a peer-reviewed venue can result in incredible impact--personal behavior change, informed nodes of trust to further disseminate factual information, and resources for community providers navigating constantly evolving knowledge," says Penn Nursing's Ashley Z. Ritter, PhD, CRNP, the article's lead author.

Dear Pandemic is an example of necessary low-barrier information exchange with the public and a tool for community providers like nurses to stay informed of breaking news. Increased engagement of nurses in endeavors like Dear Pandemic amplifies the impact of collective interdisciplinary efforts to educate the public, contain misinformation, and motivate individual and systemic action, the article explains.

"Now is the time for nurses to flex their communication and trust muscles in both traditional and innovative ways to advance the health of the public through trusted, actionable messaging in addition to exceptional patient care," says co-author Shoshana Aronowitz, PhD, CRNP, a Fellow of the National Clinician Scholars Program.

New York, NY--Research-practice partnerships (RPPs), long-term collaborations between researchers, policy makers and practitioners, represent an especially promising strategy for making sure that all children benefit from early childhood education, according to a journal released today by Princeton University and the Brookings Institution.

The journal, Future of Children, edited by Daphna Bassok of the University of Virginia and Pamela Morris of New York University's Steinhardt School, argues that RPPs are crucial for solving today's most pressing question in early childhood education--how to deliver high-quality prekindergarten programs at scale.

"Too often there is a disconnect between the questions researchers tackle and the ones that are more urgent and salient for policy makers or practitioners," said Bassok. "The findings from rigorous, well-designed research studies may not be particularly useful for addressing the real-life complexity that educators and policymakers face."

"The idea of research practice partnerships is that through close collaborations, researchers can do work that really helps policy makers address the big problems they are tackling and do the work fast enough to actually inform change," continued Morris. "Our hope is that this journal makes that clear."

RPPs are Designed to Improve Educational Outcomes

RPPs are defined by longevity, mutual decision-making and compromise, and the commitment of both parties to large-scale, systems-level problem solving, rather than a single project or research question.

In study after study, early childhood education programs developed by researchers have shown large benefits, holding out the promise of substantially narrowing the achievement gap between disadvantaged children and their better-off peers. But when cities and states establish large-scale prekindergarten programs, Bassok and Morris noted, the results are often far more modest. The important questions today aren't about whether early childhood education "works," but about how to invest limited resources to improve the quality of large-scale prekindergarten programs, support the early childhood workforce, and reach the children who need the most help.

"Delivering effective early childhood education at scale remains elusive," said Bassok. "Findings from promising research studies rarely make their way into early childhood practice; at the same time, policy and practice decisions are often made without research evidence to guide them."

That's partly because policy makers and practitioners have different priorities and work on different timelines than researchers do. Through collaboration, compromise, and long-term commitment, RPPs can help bridge the gap and produce research that's relevant and useful to policy makers and practitioners, while at the same time offering scholars opportunities for broad and innovative research wouldn't be possible in one-off studies of a single program or topic.

The Journal is a User Manual for Partnerships

Each article in the journal describes how a successful early childhood RPP confronted a major challenge or exploited an unexpected opportunity in the process of working together to create a research or funding agenda, develop measurement tools, take innovation to scale, navigate conflicting timelines, find a balance between academic rigor and feasibility, or build research capacity. In this sense, the journal offers both a user manual and a road map for future partnerships to follow.

"The COVID-19 pandemic has underlined the benefits of RPPs," Morris said. "Where RPPs were in place, researchers used their familiarity with the local context to help ease the sudden transition to remote learning."

For example, as COVID-19 spread in New York City, researchers in an established RPP there quickly assembled materials about remote learning, including a tool kit for teachers citywide, and offered resources to answer policy makers' most urgent questions.

"The pandemic has created large gaps in the services provided to our youngest learners, and opened the door for new collaborations as policy systems race to meet children's needs," continued Morris. "In this context, RPPs can support efforts to rebuild and reimagine early childhood education systems that can help all of our nation's children acquire strong foundations for kindergarten and beyond."

People living with a child who attends school in-person have an increased risk of reporting evidence of COVID-19, but teacher masking, symptom screening, and other mitigation measures in schools may be able to minimize that excess risk, suggests a study led by researchers at the Johns Hopkins Bloomberg School of Public Health.

For their study, the researchers analyzed nearly 600,000 responses from an ongoing Facebook-based COVID-19 symptom survey in the United States over two periods between November 2020 and February 2021 before vaccines were widely available in the U.S. The researchers found that those living with a child engaged in full-time, in-person pre-K-to-12 schooling were about 38 percent more likely to report COVID-19-like symptoms such as fever, cough, or difficulty breathing, compared to those living with a child schooled exclusively in a home setting.

A key finding was that school-based mitigation measures--the survey asked about 14 mitigation measures--were associated with less risk per mitigation measure. For example, 9 percent less risk of COVID-related illness per measure, and 7 percent less risk of a positive SARS-CoV-2 test per measure. Each additional mitigation measure reduced risk. Teacher masking and daily symptom screening appeared to be the strongest risk reducers.

The study was published online April 29 in Science.

The analysis included three outcomes as reported by survey respondents: COVID-19-like illness, i.e., fever and respiratory symptoms within the last 24 hours; loss of taste or small within the last 24 hours; and a positive COVID-19 test in the last 14 days.

The survey responses indicated that most pre-K-to-12 schools had some mitigation measures in place, such as mask mandates for teachers, daily screening of students and teachers for symptoms, and curtailment of extracurricular activities. The researchers found that when schools used seven or more mitigation measures, the excess risk associated with in-person schooling mostly disappeared--and completely disappeared when 10 or more mitigation measures were reported.

"These findings support the idea that mitigation measures at schools can greatly reduce the excess COVID-19 risk to adults living with children who attend school in-person," says study first author Justin Lessler, an associate professor in the Department of Epidemiology at the Bloomberg School.

The issue of in-person schooling has been much debated in the United States from the start of the COVID-19 pandemic, leading to different school policies across the country. This policy diversity effectively set in motion a "natural experiment" with schooling and COVID-19 risk in the U.S. population. A chief concern has been that children going to school every day, even if they are not very susceptible to COVID-19 themselves, may bring home the virus to parents and other adult family members who are at higher risk of disease.

To examine these issues, Lessler and colleagues used the COVID-19 Symptom Survey, an ongoing Facebook-based survey managed by Carnegie Mellon University's Delphi Group in collaboration with Facebook that garners about 250,000 responses per week. The researchers looked at responses during two recent periods--roughly from Thanksgiving to Christmas last year and mid-January to mid-February this year--from respondents in households where at least one child was enrolled in a school, from pre-kindergarten through high school. Of the 576,051 people in this group, about 49 percent, or 284,789, reported being in a household with a child attending pre-K-to-12 school in-person rather than online or homeschooled.

In their analysis, Lessler and colleagues examined how the in-person school group differed from the online or homeschooled group in terms of reported COVID-19-related symptoms and outcomes. They adjusted the results to account for obvious confounding factors such as differences in local COVID-19 rates.

In addition to the 38 percent increase in the odds of getting a COVID-19-related illness among respondents in households with an in-person-schooled child, the researchers found a 21 percent increase in the odds for the loss of taste or smell--one of the core symptoms of COVID-19--and a 30 percent increase in the odds for testing positive for SARS-CoV-2 infection in the previous two weeks.

The strength of these associations appeared to increase with grade level. At the K and pre-K level, the association with COVID-19 outcomes was not significant for all outcomes, but the strength of those associations rose steadily, peaking at the grade 9-12 level--where the excess risk of a recent positive SARS-CoV-2 test for household members was over 50 percent. These findings are consistent with past studies suggesting less susceptibility to SARS-CoV-2 infection and COVID-19 illness among younger children compared to older ones.

The survey data included responses about COVID-19 mitigation measures in schools attended by children in the respondent's household. These mitigation measures included mask mandates for teachers and students, extra space between desks, suspension of school clubs, sports, and other extracurricular activities, and daily symptom screening among teachers and students. Respondents with a child in their household attending school in person reported a mean of 6.7 mitigation measures at school--with significant variations in that figure across the country, from a mean of 4.6 measures in South Dakota schools to 8.9 in Vermont schools.

The analysis also suggested that most of the increased COVID-19-related risk was concentrated in schools with fewer than seven mitigation measures, and that in-person schooling was not associated with increased risk for any COVID-19-related outcomes among respondents living with children in schools with ten or more measures.

"Because the study is based on a self-reported symptom survey and a setting where we can't randomize students to different schooling modes and mitigation measures, it has limitations," Lessler says. "But having hundreds of thousands of respondents and the ability to control for geographic and individual-level characteristics helps make up for those limitations."

He and his colleagues plan to follow up with studies of how in-person schooling and school-based mitigation measures affect community-wide spread of COVID-19.

"Household COVID-19 risk and in-person schooling" was co-authored by Justin Lessler, M. Kate Grabowski, Kyra Grantz, Elena Badillo-Goicoechea, C. Jessica Metcalf, Carly Lupton-Smith, Andrew Azman, and Elizabeth Stuart.

A new study led by University of Minnesota astrophysicists shows that high-energy light from small galaxies may have played a key role in the early evolution of the Universe. The research gives insight into how the Universe became reionized, a problem that astronomers have been trying to solve for years.

The research is published in The Astrophysical Journal, a peer-reviewed scientific journal of astrophysics and astronomy.

After the Big Bang, when the Universe was formed billions of years ago, it was in an ionized state. This means that the electrons and protons floated freely throughout space. As the Universe expanded and started cooling down, it changed to a neutral state when the protons and electrons combined into atoms, akin to water vapor condensing into a cloud.

Now however, scientists have observed that the Universe is back in an ionized state. A major endeavor in astronomy is figuring out how this happened. Astronomers have theorized that the energy for reionization must have come from galaxies themselves. But, it's incredibly hard for enough high energy light to escape a galaxy due to hydrogen clouds within it that absorb the light, much like clouds in the Earth's atmosphere absorb sunlight on an overcast day.

Astrophysicists from the Minnesota Institute for Astrophysics in the University of Minnesota's College of Science and Engineering may have found the answer to that problem. Using data from the Gemini telescope, the researchers have observed the first ever galaxy in a "blow-away" state, meaning that the hydrogen clouds have been removed, allowing the high energy light to escape. The scientists suspect that the blow-away was caused by many supernovas, or dying stars, exploding in a short period of time.

"The star-formation can be thought of as blowing up the balloon," explained Nathan Eggen, the paper's lead author who recently received his master's degree in astrophysics from the University of Minnesota. "If, however, the star-formation was more intense, then there would be a rupture or hole made in the surface of the balloon to let out some of that energy. In the case of this galaxy, the star-formation was so powerful that the balloon was torn to pieces, completely blown-away."

The galaxy, named Pox 186, is so small that it could fit inside the Milky Way. The researchers suspect that its compact size, coupled with its large population of stars--which amount to a hundred thousand times the mass of the sun--made the blow-away possible.

The findings confirm that a blow-away is possible, furthering the idea that small galaxies were primarily responsible for the reionization of the Universe and giving more insight into how the Universe became what it is today.

"There are a lot of scenarios in science where you theorize that something should be the case, and you don't actually find it," Eggen said. "So, getting the observational confirmation that this sort of thing can happen is really important. If this one scenario is possible, then that means that there are other galaxies that also existed in blow-away states in the past. Understanding the consequences of this blow-away gives direct insight into the impacts similar blow-aways would have had during the process of reionization."

DALLAS, April 29, 2021 – Last Friday, the Centers for Disease Control and Prevention (CDC) and the U.S. Food & Drug Administration (FDA) lifted the pause in administration of the Johnson & Johnson (Janssen) COVID-19 vaccine in the U.S. The temporary pause was due to reports of a serious condition called cerebral venous sinus thrombosis (CVST), which refers to blood clots in the brain’s veins - not in the arteries, as is the case for most strokes - in combination with thrombocytopenia (low blood platelet count). CVST and thrombocytopenia together is called thrombosis-thrombocytopenia syndrome (TTS). When TTS is linked to receiving a COVID-19 vaccine, it is called vaccine-induced immune thrombotic thrombocytopenia (VITT). CVST has also been associated with cases of TTS in adults who received the AstraZeneca COVID-19 vaccine available in Europe, according to the European Medicines Agency, the agency responsible for the scientific evaluation, supervision and safety of medicines in the European Union.

The American Heart Association/American Stroke Association Stroke Council Leadership convened quickly to provide important guidance about CVST, TTS and VITT – the signs and symptoms and the best treatment options. The special report, “Diagnosis and Management of Cerebral Venous Sinus Thrombosis with Vaccine-Induced Thrombotic Thrombocytopenia,” published today in Stroke, a journal of the American Stroke Association, a division of the American Heart Association.

“COVID-19 infection is a significant risk factor for CVST. A preliminary analysis of U.S. data during the COVID-19 pandemic, available online, preprint on April 15, 2021, found that the risk of CVST due to infection with COVID-19 is 8-10 times higher than the risk of CVST after receiving a COVID-19 vaccine,” said Karen L. Furie, M.D., M.P.H., lead author of the special report, chair of the department of neurology at The Warren Alpert Medical School of Brown University, and chief of neurology at Rhode Island Hospital, The Miriam Hospital and Bradley Hospital in Providence, Rhode Island. “The public can be reassured by the CDC’s and FDA’s investigation and these statistics – the likelihood of developing CVST after a COVID-19 vaccine is extremely low. We urge all adults to receive any of the approved COVID-19 vaccines.”

The analysis included data from 59 health care organizations, totaling 81 million patients, more than 98% of whom were in the U.S. Among the nearly 514,000 patients in the database who were diagnosed with COVID-19 infection from January 20, 2020 through March 25, 2021, 20 patients were diagnosed with CVST. This data was compared to the incidence of CVST in adults who received either the Pfizer or Moderna COVID-19 vaccine before March 25, 2021, excluding those who had previously been diagnosed with COVID-19. No cases of thrombocytopenia (low platelets) were diagnosed among almost 490,000 vaccinated adults.

“CVST blood clots are very rare adverse events. We recommend immediate screening of all patients who arrive in the ER with a suspected clot – did they receive a COVID-19 vaccine during the recent weeks prior to this event?” said Furie. “Patients who present with the symptoms of CVST or blood clots and who recently received the COVID-19 vaccine should be treated using non-heparin anticoagulants. No heparin products in any dose should be given for suspected CVST, TTS or VITT. With the right treatment, most patients can have a full recovery after CVST, TTS or VITT.”

CVST is an extremely rare but serious type of stroke caused by a blood clot in a part of the brain known as the venous sinus, involving veins that carry blood away from the brain. CVST clot symptoms are very similar to several other neurological conditions, and the symptoms can include severe headache; blurry vision; fainting or loss of consciousness; weakness; sensory changes; confusion or trouble speaking; seizures; abdominal pain; leg pain; difficulty breathing or shortness of breath. CVST occurs in the veins of the brain; blood clots may also occur in other blood vessels, like those in the legs, lungs or abdomen. Among the cases reported in the U.S., the most common symptoms were severe headaches; vomiting; back pain; fatigue; weakness or the inability to move one side of the body (hemiparesis); inability to speak or understand speech (aphasia); loss of consciousness; and abdominal pain.

If associated with the COVID-19 vaccine, cases of TTS/VITT occurred several days up to 2-1/2 weeks after being vaccinated with the Johnson & Johnson (Janssen) COVID-19 vaccine in the U.S., or up to 3-1/2 weeks after receiving the AstraZeneca COVID-19 vaccine in Europe.

The CDC and FDA’s report on April 23, 2021, confirms the agencies investigated 15 reported cases of TTS in the U.S., in women ages 18-59 years, from the nearly 7 million adults who received the Johnson & Johnson COVID-19 vaccine before the temporary pause on April 13, 2021. The European Medicines Agency’s investigation, reported on April 7, 2021, lists 62 cases of CVST, among adults ages 22-60 years, mostly women, from the more than 25 million people who received the AstraZeneca COVID-19 vaccine throughout the European Union .

The special report from the Stroke Council leaders details treatment for suspected CVST, TTS or VITT:

All patients with suspected CVST due to a COVID-19 vaccine should be treated with non-heparin anticoagulants such as argatroban, bivalirudin, danaparoid, fondaparinux or a direct oral anti-coagulant (DOAC). No heparin products in any dose should be given.

Magnetic Resonance Imaging with a venogram (MRI/MRV) or computed tomography with venogram (CT/CTV) is recommended to accurately detect and diagnose CVST.
Blood tests should include a CBC (Complete Blood Count) plus:
platelet count - to determine the number of platelets per liter of blood;
a peripheral smear - examination under a microscope to count the number of various types of blood cells and if they appear normal;
a prothrombin time – to measure how long it takes the blood to clot;
a partial thromboplastin time – a measurement of how long it takes the blood to clot, specifically measuring for these clotting factors: factor VIII, factor IX, factor 1V and factor XII;
a fibrinogen test – to measure for the presence of fibrin, a protein found in the blood that indicates that blood clotting has been activated;
a D-dimer test – to measure for the presence of D-dimer, a small protein that’s made when blood clots are dissolving in the body; and
a PF4 antibody ELISA test – to test for PF4 antibodies, which the body sometimes creates in the blood to fight against the anticoagulant heparin.
Anticoagulation treatment doses may need to be tailored if platelet counts are extremely low (<20,000/mm3) or if there is low fibrinogen.
Anticoagulants should be used to treat CVST even if there is a secondary hemorrhage in the brain in order to prevent progressive thrombosis and to control bleeding.
Platelet transfusion should be avoided.
Once platelet counts return to normal (150,000 to 450,000/mm3), most patients can be transitioned to an oral anticoagulant if there are no contraindications.
The authors note that based on their evaluation of the American Society of Hematology’s recommendations and two recently published studies, individual patient factors should be considered regarding the use of a direct oral anticoagulant (DOAC) or a vitamin K agonist (VKA) after there is full platelet count recovery.
The authors recommend all cases of thrombosis after a COVID-19 vaccine be reported to the U.S. Department of Health and Human Services Vaccine Adverse Event Reporting System: https://vaers.hhs.gov/reportevent.html. This data will be important to understanding the incidence of CVST, TTS and VITT.
There is still much to be investigated:
Are there any preexisting conditions that may predispose someone to CVST or VITT?
What is the true prevalence and risk of PF4 antibodies, low platelet count and CVST after the COVID-19 vaccine?
Since there is currently no data about people who did not develop CVST, TTS or VITT after a COVID-19 vaccine for comparison, it is not possible to definitively state that the vaccine is the cause of the PF4 antibodies, low platelet count (thrombocytopenia) or blood clots (thrombosis).

“We are learning the various intricacies of COVID-19 live, in real-time with the patients we see in our hospitals every day. CVST is extremely rare, however, further research and investigation are necessary as the pandemic continues. We will need data and robust research on the people who did not develop blood clots after the vaccine, too, so that we can fully understand the molecular and cellular mechanisms underlying CVST related to COVID-19 infection or after vaccination,” concluded Furie.

The following statement reflects the views of the American Heart Association/American Stroke Association and its science leaders:

President Mitchell S.V. Elkind, M.D., M.S., FAHA, FAAN,
Immediate Past President Robert A. Harrington, M.D., FAHA,
President-Elect Donald M. Lloyd-Jones, M.D., Sc.M., FAHA,
Chief Science and Medical Officer Mariell Jessup, M.D., FAHA, and
Chief Medical Officer for Prevention Eduardo Sanchez, M.D, M.P.H., FAAFP.

“The American Heart Association continues to urge everyone to receive a COVID-19 vaccine as soon as they can. We concur with the CDC’s and FDA’s recommendations for people who receive the Johnson & Johnson (Janssen) vaccine – if they develop severe headache, abdominal pain, leg pain or shortness of breath within 3 weeks of receiving the vaccine, they should quickly contact their health care professional.

COVID-19 has disproportionately negative effects on older adults; people with underlying medical conditions; and Black, LatinX and American Indian/Alaska Native people. The American Heart Association strongly encourages everyone to get vaccinated with an approved COVID-19 vaccine. In particular, people with cardiovascular risk factors such as high blood pressure, obesity and type 2 diabetes, those with heart disease, and heart attack and stroke survivors should get vaccinated as soon as possible because they are at much greater risk of a negative outcome from the virus than they are from the vaccine.

We are confident the benefits of vaccination far exceed the very small, rare risks. The risks of vaccination are also far smaller than the risks of COVID-19 and its potentially fatal consequences.

We recommend people who have medical conditions, especially those with the propensity for blood clotting, consult with a health care professional before seeking vaccination to discuss the very rare potential increased risks.

In addition, the Association reiterates the importance of handwashing, social distancing and wearing masks as vaccinations continue, particularly for people at high risk of infection and/or severe COVID-19. These simple precautions remain crucial to protecting people from the virus that causes COVID-19. They also are crucial to getting us all back to normal activities.

Individuals should refer to their local and state health departments for specific information about when and where they can get vaccinated. We urge everyone to get vaccinated.”

DALLAS, April 29, 2021 -- Health care professionals should consider prescribing medication for patients with slightly elevated blood pressure if levels do not decrease after six months of healthy lifestyle changes, according to a new scientific statement from the American Heart Association. The statement, published today in the Association's journal Hypertension, fills a gap in guideline recommendations by addressing how to manage untreated, stage 1 high blood pressure - levels of 130-139/80-89 mm Hg - that was not fully addressed in the 2017 treatment guidelines.

The 2017 American College of Cardiology/American Heart Association Blood Pressure Management Guidelines' recommendation for patients with stage 1 hypertension and a low (10%) 10-year risk for heart attack or stroke, the guidelines recommend anti-hypertensive medication in addition to healthy lifestyle.

Today's scientific statement suggests clinicians should consider medication for patients with a low ten-year risk if the blood pressure goals (

"There are no treatment recommendations in current guidelines for patients who are at relatively low short-term risk of heart disease when blood pressure does not drop below 130 mm Hg after six months of recommended lifestyle changes," said Daniel W. Jones, M.D., FAHA, chair of the statement writing group, professor and dean emeritus at the University of Mississippi School of Medicine in Jackson, Mississippi, and a past president of the American Heart Association. "This statement fills that gap."

Many patients who have stage 1 high blood pressure are adults under the age of 40. Randomized controlled trials following these patients for cardiovascular disease risk are lacking, therefore, the statement writing committee relied on other forms of evidence including observational studies focused on the relationship between blood pressure and cardiovascular disease.

"We know that people with blood pressure lower than 130/80 mm Hg have fewer markers of cardiovascular risk like elevated coronary calcium, enlargement of the heart, or buildup of fatty deposits called atherosclerosis in arteries of the neck. There is strong evidence that treating high blood pressure saves lives by reducing the risks for heart attack and stroke," Jones said.

Healthy lifestyle changes to lower blood pressure include achieving ideal body weight, exercising (30 minutes on most days of moderate to vigorous physical activity, if possible), limiting dietary sodium, enhancing potassium intake and following the Dietary Approaches to Stop Hypertension (DASH) diet (combination diet of fruits and vegetables with low-fat dairy products and reduced saturated fat and total fat). In addition, patients should be recommended to limit alcohol and not smoke. These remain the cornerstone of cardiovascular disease prevention.

"If after six months with lifestyle changes, blood measure does not improve, clinicians should consider adding medications to control blood pressure," said Jones. "That's an important message for patients to hear as well because they should check their blood pressure regularly to monitor progress. If they don't achieve average daily systolic blood pressure less than 130 mm Hg, it's probably time to initiate a conversation with their doctor about practical next steps, which may include adding medication, to manage their blood pressure."

For people who took blood pressure-lowering medication as adolescents, there is evidence that, without intervention, these individuals are likely to develop markers of cardiovascular disease in young adulthood. The statement suggests the original indication for beginning treatment, usually to ward off organ damage from long-term high blood pressure, should be considered in assessing the need to continue medication.

The statement writers acknowledge that the goals of lifestyle change are difficult to achieve and maintain over time. "It is very hard in America and most industrialized countries to limit sodium sufficiently to lower blood pressure," said Jones, "and it is difficult for all of us to maintain a healthy weight in what I refer to as a toxic food environment. We want clinicians to advise patients to take healthy lifestyle changes seriously and do their best. We certainly prefer to achieve blood pressure goals without adding medication; however, successfully treating high blood pressure does extend both years and quality of life."

CHAMPAIGN, Ill. -- Researchers have created a new, open-access tool that allows doctors and scientists to evaluate infant brain health by assessing the concentration of various chemical markers, called metabolites, in the brain. The tool compiled data from 140 infants to determine normal ranges for these metabolites.

Published in the journal NMR in Biomedicine, the study describes an easier and more reliable way to evaluate metabolite concentrations in the infant brain than was previously available, said study lead Ryan Larsen, a researcher at the Beckman Institute for Advanced Science and Technology at the University of Illinois Urbana-Champaign.

Metabolites play an important role in normal brain growth, development and function, said study co-author Dr. Ellen Grant, the director of the Fetal Neo-Natal Neuroimaging and Developmental Science Center at Boston Children's Hospital and a professor of radiology and of pediatrics at Harvard Medical School. High or low metabolite levels in the brain may be the first sign of problems with brain function or development.

"For example, we look at choline, which plays a role in building myelin, the sheath that allows electrical impulses to travel along neurons," Grant said. "Another metabolite, called NAA, is important to the healthy growth and proliferation of dendrites, the branches on neurons that receive signals from other neurons."

By measuring the concentration of key metabolites like these, researchers can spot some problems early - allowing interventions in time to prevent damage to the growing brain, she said.

Assessing metabolites in the brain normally involves proton magnetic resonance spectroscopy, a technology that uses an MRI not for visual imaging but to detect and identify specific molecules in the tissues of interest. The most common approach requires extensive imaging and detailed calculations of the amount of water inside and outside brain tissues to standardize these measures, a costly and time-consuming approach.

To address this difficulty, Grant and study co-author Borjan Gagoski, a radiology instructor at Boston Children's Hospital, used proton MRS to scan the brains of 140 infants at approximately one month and three months of age. In addition to using water as a reference, the team also compiled data from several key metabolites in their calculations. This allowed them to create a tool that makes use of standard values for several metabolites when assessing the concentration of any one metabolite in an infant's brain.

"What most everybody does is they look at a simple ratio between metabolite 1 and metabolite 2," Larsen said. "But if that ratio is low, does that mean that metabolite 1 is low or that metabolite 2 is high? It becomes a problem of interpretation."

Instead, the team painstakingly assessed relationships between seven key metabolites to build a database of normal values for each one at different time points, and to show how metabolite concentrations change in relation to one another as the infant's brain develops.

The tool the team developed offers a checklist of reference brain metabolites that users can select in different combinations to more clearly understand an individual infant's profile.

"Spectroscopy is really tough to do but when it's done in the right way, it can help us find out more about the brain," Gagoski said. "This approach has great potential because we can detect abnormalities and diseases before we can actually see anything on the structural scans. And it's really important to monitor brain health at this stage of life."

Eye contact plays a fundamental role in human communication and relationships. When we look into each other's eyes, we show that we are paying attention to each other. However, we do not only look at each other but also at our four-legged companions. According to new research by Hungarian ethologists, at least four independent traits affect dogs' ability to establish eye contact with humans. Short-headed, cooperative, young, and playful dogs are the most likely to look into the human eye.

Dogs adapted uniquely well to live with humans, and communication plays a vital role in this. They are sensitive to the direction of the human's gaze, which helps them decide whether the message is directed to them. Forming eye contact with the owner raises oxytocin levels in both parties, which plays a role in developing social bonding. However, individual dogs are not equally prone to make eye contact; the anatomy of the eye, the original function of the breed, i.e., the task they were bred for, age and personality might also affect the tendency to form eye contact.

"One hundred and thirty family dogs were examined at the Department of Ethology, Eötvös Loránd University. We measured the length and width of their heads because this is related to their vision." - said Zsófia Bognár, Ph.D. student, first author of the study, published in Scientific Reports. "The boxer, bulldog, pug, and snub-nosed dogs, in general, have a more pronounced area centralis in the retina, so they can better respond to stimuli in the central field, which may make it easier for them to form eye contact with humans."

In contrast, long-nosed dogs, such as greyhounds, see a wide panoramic image because the nerve cells that process the visual information distribute more evenly in their retina. Therefore, if they have to focus on the center of their visual field, they may be distracted by visual stimuli from the periphery more easily.

In the behavior test, the experimenter first initiated play with the dog. In another test, she measured how quickly and how many times the dog formed eye contact with her within five minutes. "The experimenter did not speak and remained motionless until the dog looked at her. Every time the dog looked at her, she rewarded this with a treat. Meanwhile, the owner sat on a chair, silent. We measured how much time elapsed after eating the treat until the next eye contact." - presented the test Dr. Dóra Szabó, ethologist. See the video summary of the research here.

It turned out that the shorter the dog's nose, the faster it made eye contact with the experimenter. "It is likely, that they see the human face more sharply because of their special retina, but it is also possible that their owners gaze at them more often as their facial features resemble a small child, a powerful cue for humans. Because of this, dogs with shorter noses may be more experienced in making eye contact." - explained Zsófia Bognár.

The researchers also examined whether the original role of the breeds still influenced eye contact forming. Shepherd dogs, for example, are visually cooperative who follow the direction of the owner's hand (stick) during their work with the stock. In contrast, visually non-cooperative sled dogs running in front of the musher can only rely on vocal cues, while dachshunds also cannot see their owner in the underground life-and-death struggle. Long- and short-headed dogs evenly distributed across the different breed groups.

As expected, dogs bred for visually guided work made eye contact faster than those driven by voice or selected for independent work. Surprisingly, the mixed breeds performed similarly well, even though 70% were adopted from a shelter. Perhaps their willingness to make eye contact even helped them to get adopted in the first place.

The research was part of the European Research Council funded Senior Family Dog Project, aimed at aging research. The oldest dog participant was 15 years old.

"We assumed that aging dogs would find it more difficult to control their attention and would be slower to switch from eating to looking at the face of the experimenter. That's what happened. Since we pre-screened our participants for potential visual and auditory impairments, the slower establishment of eye contact seems to be a natural consequence of aging." - says Dr. Eniko Kubinyi, the leader of the project.

This research emphasizes the fact that many factors affect the way dogs and humans communicate. It also sheds new light on our knowledge of short-nosed dogs. Many researchers, including Konrad Lorenz, suggested that these dogs were selected for their baby-like facial appearance. However, it is also plausible that people preferred individuals that were more attentive to them and looked at them for a longer duration, facilitating communication.

The Korea Institute of Civil Engineering and Building Technology (KICT) has announced the development of an effective structural monitoring technique to monitor massive infrastructures, such as long-span bridge. The method provides accurate and precise responses over whole structural system densely by fusing advantages of multi-fidelity data.

Rapid advances in sensing and information technologies have led to condition-based monitoring in civil and mechanical structural systems. The structural monitoring system plays a key role in condition-based monitoring to evaluate structural safety from responses measured by sensors. In other words, following method allows to examine the health of an existing structures, such as a long-span bridge. The structural monitoring system can enable early detection for an unsafe condition and enable proactive maintenance. As a result, it greatly reduces the inspection burden as well as maintenance costs. The prerequisite for the successful condition-based monitoring is to obtain accurate responses through the whole structural system. Especially in civil-infrastructures, high cost, and technical difficulty are some challenging issues.

In order to solve this problem, a research team in KICT, led by Dr. Seung-Seop Jin, has developed an effective as well as efficient data-fusion method for condition-based monitoring. With the following method, the complementary data-fusion for the point and distributed strain sensor is performed to combine their advantages in order to obtain the accurate strain distribution over whole infrastructures; thereby, responses can be estimated with high accuracy densely over whole infrastructures.

For structural response, the multi-fidelity data consists of point and distributed sensors, which have different fidelities. The point sensor provides high accurate and reproducible responses at discrete measurement positions (High-fidelity data, HF-data), while a distributed sensor utilizes the scattering-based or scanning sensing technique to obtain very dense responses using the quasi-continuous sensing (Low-fidelity data, LF-data). The LF data is relatively easy to acquire, so it is possible to produce large amounts of relatively inaccurate data for response trend over whole infrastructure. On the contrary, the HF data provides high accuracy; however, it is limited to acquire in terms of both time and technical limitations. Therefore, the limited amount of data is available and this can significantly impair the ability to diagnose structural conditions over whole infrastructures. Although they can be complemented each other, their complementary data-fusion has not been studied yet for the structural monitoring system. KICT firstly recognizes their potentials and developed the complementary data-fusion framework by exploiting a multi-fidelity modeling in Computational statistics and Geo-statistics. The basic concept of the developed method is to transfer knowledge of the abundant but potentially inaccurate LF-data (response trend) to enhance their accuracies by fusing the information from the HF-data (accuracy at some points).

The newly developed method was verified by a number of the numerical tests with other existing multi-fidelity data-fusion methods. In order to consider possible situations in real applications, the developed method was extensively evaluated through Monte Carlo simulations by varying the number and locations of multi-fidelity data with the noise. The results show that the prediction performance of the developed method is consistently superior to other existing methods. In both experiments, the relative percentages of accuracy (maximum absolute error) are improved up to 171.3% and 192 % to the existing methods.

The method is very versatile for structural monitoring, especially for massive infrastructures. The developed method is currently improved to make it more robust and efficient. For better generalized capability, the developed method requires flexible learning capability for extracting the information from both the HF-data and LF-data and fusing them. Such improvements include the following.

Dr. Jin said, "The rationale behind this improvement is similar to our decision-making in real life. We seek different options and combine them to make the best decision. Similar to our decision-making, we do not have high confidence on the unknown damages. In the current method, we have to utilize specific models and some parameters in these models. It should be noted that a best model and its parameters are case-dependent. Therefore, we pursue several options for flexible modeling. To deal with various conditions in infrastructures, we can adopt a flexible and self-learning framework such as optimal kernel learning for better data-fusion. This idea takes a step towards autonomous and efficient monitoring system for massive infrastructures."