Culture

The adult brain is more malleable than previously thought, according to researchers from the Interdisciplinary Center Herzliya. They trained a 50-year-old man, blind from birth, to "see" by ear, and found that neural circuits in his brain formed so-called topographic maps - a type of brain organization previously thought to emerge only in infancy. This finding reported recently in Neuroimage, sheds new light on the brain's ability for change and holds promise for helping people restore lost function, for example, after a stroke.

"The human brain is indeed more plastic during infancy, but it maintains an enormous potential for reprogramming throughout a person's life," says Prof. Amir Amedi, head of the Baruch Ivcher Institute for Brain, Cognition & Technology at IDC Herzliya, whose team conducted the study.

This research is Amedi's latest challenge to the classic theory of brain organization, according to which the brain has specialized regions, each geared to processing a particular type of sensory information - visual, auditory and so on. The theory holds that for these regions to become organized properly, we must be exposed to the relevant stimuli early in life. This view stems from seminal studies by David H. Hubel and Torsten N. Wiesel - awarded the 1981 Nobel Prize in Physiology or Medicine for this research - showing that without exposure to such stimuli during a critical period in early life, the corresponding sensory system fails to develop. After the critical period, the brain is considered to experience a progressive loss of plasticity, that is, the ability to modify itself based on novel experiences.

But over the past decade, evidence has been accumulating that the brain's sensory regions can handle stimuli outside their "specialization." In a recent review in Neuroscience and Biobehavioral Reviews, Prof. Amedi and Dr. Benedetta Heimler bring together compelling findings in healthy as well as visually- and hearing-impaired individuals, showing that sensory regions deprived of their natural input can be activated by atypical senses - for example, the visual cortex can be activated by sound or touch.

Moreover, the researchers cite studies, including those in Amedi'a lab, in which such atypical activation was achieved in adults. They call for revising the classical concept of critical periods of development: instead of a fixed time window in early life, they suggest focusing on the brain's ability to acquire specialization throughout a person's lifetime, in other words, reversing the loss of plasticity.

In the new study in Neuroimage, Amedi's team trained a man, blind from birth - identified as MaMe, by the first syllables of his first and last name - to recognize objects using a sensory substitution algorithm the lab had developed. The method, EyeMusic, converts visual stimuli into "soundscapes," sound units that convey information about geometric shapes. They convey positions on the y axis by musical pitch, and those on the x axis by time. Thus, tones of a higher pitch denote higher locations, whereas their ordering in time corresponds to their respective positioning from left to right. The researchers scanned MaMe's brain using functional magnetic resonance imaging, before the training and after he had successfully learned to recognize soundscapes.

Hofstatter describe the intriguing results: "After MaMe had learned to interpret soundscapes, his neural circuits were shown to be activated not only in the auditory cortices, but also in the occipital cortex, which receives visual stimuli in sighted people and is not expected to be activated in a congenitally blind individual". Amedi adds: "Not only that, the activation followed a pattern of topographical maps - the highly ordered manner in which external stimuli are mapped in all the sensory systems of the human brain. For example, in the visual cortex of sighted people, neighboring locations are "mapped" onto adjacent neurons, whereas places at a great distance from one another are represented by neurons that are further apart.

MaMe's scans revealed topographic maps tuned to pitch and time - or even to both concurrently - that had not existed in his brain before he'd started the training. For instance, tones of a similar pitch were represented by adjacent neurons, whereas those of radically different pitches - by neurons that were distant from one another. This is the first time topographic maps have been shown to emerge in an adult human brain.

These findings suggest that the brain's sensory regions are primed for specific computations but not specific senses, and that they can be adapted to processing novel sensory experiences.

In fact, past studies by other researchers had shown in newborn laboratory animals that it's possible to "move" the vision function to the brain's hearing region by surgically guiding nerve fibers from the visual cortex to the auditory one. The new study by Hofstetter and colleagues supplies a proof of concept that a similar transition can be done in a noninvasive manner, and in an adult, rather than infant, brain.

"Critical periods are not permanent cut-off points for developing new sensory abilities - rather, in a way, we can give the brain a second chance at any point in life," Amedi says.

He points out that EyeMusic can teach people to develop an ability that is similar to that of bats and dolphins: extracting information about geometric shapes from complex sounds. A major difference, of course, is that the animals had developed this natural ability in the course of hundreds of thousands of years of evolution, whereas in the lab, it can be acquired after a relatively short training.

"With the right technology, one can induce a speeded-up evolution of sorts in the sensory brain," Amedi says.

UNIVERSITY PARK, Pa. -- In the late 1800s, scientists were stumped by the "yellow cells" they were observing within the tissues of certain temperate marine animals, including sea anemones, corals and jellyfish. Were these cells part of the animal or separate organisms? If separate, were they parasites or did they confer a benefit to the host?

In a paper published in the journal Nature in 1882, biologist Sir Patrick Geddes of Edinburgh University proffered that not only were these cells distinct entities, but they were also beneficial to the animals in which they lived. He assigned them to a new genus, Philozoon -- from the Greek phileo, meaning 'to love as a friend,' and zoon, meaning 'animal' -- and then promptly changed his career direction to pioneer professions in urban planning and design. Over time, Geddes's scientific contributions were largely forgotten, and the Philozoon genus name was never used.

Now, more than a century after Geddes's paper was published, an international team of researchers has revisited these "yellow cells," which, after Geddes, had been determined to be photosynthetic algae in the family Symbiodiniaceae.

In a study published in the June 28 issue of the
European Journal of Phycology, the team resurrected the genus Philozoon by using modern technologies to thoroughly characterize two of the species of algae that Geddes had investigated, along with six new related ones.

"Patrick Geddes was ahead of his time in recognizing the ecological significance of the 'yellow cells' found in some animals were actually distinct entities -- micro-algal symbionts -- existing inside the animal's tissues and creating a photosynthetic animal. That was a major revelation! In fact, we now know that microorganisms live in partnership with all multicellular organisms; for example, the bacteria that comprise our human gut microbiomes are essential for our overall health," said Todd LaJeunesse, professor of biology, Penn State, and lead author of the paper. "By emending and reviving the Philozoon genus, we are honoring the work of this natural historian.

LaJeunesse and his colleagues used genetic information; outward physical, or morphological, characteristics; ecological traits; and geographic distributions to define the diversity found within the newly recognized Philozoon genus. They obtained animal samples -- including from soft and stony corals, jellyfish, and sea anemones -- from locations all over the world. They also obtained samples from Italy where Geddes first conducted his original research.

"Because our team comprises scientists from seven countries, we were able to collect all of these samples, and some during the global pandemic," said LaJeunesse. "This study highlights how the spirit of scientific discovery brings people together, even in times of hardship."

"The fact that these algae exist in animals from the Mediterranean Sea to New Zealand to Chile reminds us how widespread these symbioses are on Earth," said LaJeunesse. "Also, since most of the algae in the family Symbiodiniaceae have been thought to be mostly tropical where they are critical to the formation of coral reefs, finding and describing these new species in cold waters highlights the capacity of these symbioses to evolve and live under a broad range of environmental conditions. Life finds a way to persist and proliferate."

The team documented that at their northernmost and southernmost latitudinal extremes, Philozoon experience water temperatures that may reach winter lows of nearly 40 degrees F and summer highs of close to 90 F.

"The abilities of these Philozoons to withstand a wide range of temperatures is likely due to their diversification during the cooler periods of the late Pliocene and most recent Pleistocene epochs," said LaJeunesse. "This adaptation to a range of temperatures could protect them and the animals with which they associate from some of the effects of climate change, at least in the near term. Similarly, adaptation to high latitude environments may condition Philozoon species to tolerating future increases in atmospheric carbon dioxide, which could also help make them resilient to some of the effects of ocean acidification."

He added that careful identification and categorization of these symbiotic algae is essential to understanding the biology and evolution of marine animals that rely on these organisms for their survival.

"The advanced molecular-genetic techniques available to us today have substantially improved our ability to study and understand these microbes," said Pilar Casado-Amezúa, researcher, HyT Association, Spain. "Our new study lays the groundwork for extensive research on the ecological role of animal-algal mutualisms in temperate marine ecosystems."

LaJeunesse noted that although there were a handful of other scientists during the late 1800s that were investigating these 'yellow cells' it was Geddes who unequivocally recognized the full significance of the evidence before him.

He explained, "In describing the associations between the cells and the host animals, Geddes called them 'animal lichens' and eloquently wrote, 'Such an association is far more complex than that of the fungus and alga in the lichen, and indeed stands unique in the physiology as the highest development, not of parasitism, but of the reciprocity between the animal and vegetable kingdoms.' Geddes vigorously contended that these algae were symbiotic in nature. Now, more than a century after their discovery, the true identities of these algae are finally being properly characterized."

Giving women in India's Madhya Pradesh state greater digital control over their wages encouraged them to enter the labor force and liberalized their beliefs about working women, concluded a new study co-authored by Yale economists Rohini Pande and Charity Troyer Moore.

The study, published in the American Economic Review, found that a relatively simple intervention directed to poor women -- providing them access to their own bank accounts and direct deposit for their earnings from a federal workfare program, along with basic training on how to use local bank kiosks -- increased the amount they worked, both in the government program and for other employers.

The women who had access to the banking resources were more likely to report in surveys that a working woman made "a better wife" and that husbands with working wives were better spouses and providers. They also were less likely to say women who work outside the home bear social costs for it.

The study points to the role of gender norms in India's low and declining rate of women in the workforce and it also demonstrates that boosting women's control of their finances can expand their autonomy, said Pande, the Henry J. Heinz II Professor of Economics in Yale's Faculty of Arts and Sciences.

"Economics research often assumes that a country's men and women embrace the same cultural norms, but our study highlights the fact that norms can be differently experienced and held within the same country or culture," said Pande, who is also director of Yale's Economic Growth Center. "Improving a woman's access to her earnings should cause her to work less because she can make the same amount of money with less effort. That we found women work more suggests that some women would prefer to work but are potentially being constrained by social stigma perceived by their husbands' -- specifically, that working wives diminish their husband's social status."

India experienced a period of strong economic growth between 2005 and 2018 with declining fertility rates and gains in education for women, but the rate of female labor force participation fell from 32% to 21% during that period. However, one-third of Indian housewives say in surveys that they are interested in working outside the home. Bringing these latent workers into the workforce would contribute substantially to the country's economic growth, Pande said.

Working in northern Madhya Pradesh, a region marked by particularly restrictive gender norms, the research team collaborated with government and banking partners to enable direct deposit of women's wages from the federal workfare program into their own bank accounts rather than into a male-controlled household account. They conducted a randomized controlled trial covering 197 village clusters and surveyed a total of 4,300 women. The villages were divided among a control group and four treatment groups, only one of which received bank accounts, direct deposit, and training. The researchers refer to this group as being "digitally empowered."

The study found an overall increase in labor supply among digitally empowered women compared to women who only received a bank account. They were 28% more likely to have participated in the workfare program during the past year than were the women who only received a bank account and 13% more likely to report any paid work in the previous month, according to the findings. The digitally empowered group also earned 24% more (950 rupees) annually from the private sector, which is notable given that the direct deposit was only linked to workfare wages and private-sector work often is paid in cash.

"The fact that digitally empowered women were earning more in the private sector suggests that having more control of their earnings spread into other aspects of their lives, giving them the ability to negotiate with other household members to work more outside their homes," said Troyer Moore, director of South Asia economics research at Yale's MacMillan Center for International and Area Studies. "It tells us that a simple policy intervention has altered a cultural norm, which is very exciting."

The researchers separated the sample into two groups: women who had worked in the government program before, and those who had not. In surveys, women in the latter group reported having less decision-making power, and that their husbands were more likely to associate a working wife with social stigma. The data showed that while the increases in work outside the home trailed off among those who had previously worked in the program by the study's third year, it persisted for the socially constrained group, demonstrating that the intervention had the most durable impact on women facing the greatest barriers to work.

Study participants were surveyed to measure their thoughts about working and non-working women. The results showed that, compared to women who received only bank accounts, digitally empowered women liberalized their personal beliefs about women's work.

While researchers were conducting the study, the Indian government began scaling up direct deposit of workfare wages into female-owned accounts nationwide, but the effort involved neither targeted outreach to eligible women nor any systematic account training, key elements of the most successful intervention that the study identified, the researchers said.

"We look forward to working with government partners to scale up the policy intervention in a manner that maximizes the benefits to women," Troyer Moore said.

Based on fossil finds, we know that the vast majority of species that once inhabited the earth have become extinct. For example, there are about 5,500 mammal species living on the planet today, but we know of at least 160,000 fossil species, so for every mammal species living today, there are at least 30 extinct ones. We therefore know with great certainty that the lineages of living things come and go along immense time scales. But what factors cause these lineages to come into being and disappear is still an unsolved question.

To investigate this problem more closely, the research team focused on a charismatic group: the proboscideans, which include today's elephants, but also the extinct mammoths, mastodons and dinotheria. The history of the proboscideans is one of glory and decline. Although today there are only three species of elephants left in Asia and Africa, we know fossil more than 180 species of these animals, which also inhabited Europe, South America and North America. "In the past, more than 30 species of these giants lived on the planet at the same time, and many ecosystems were so productive and ecologically complex that it was not uncommon for three or more species of proboscideans to live together in the same ecosystem," explains Juan López Cantalapiedra, a researcher at the University of Alcalá in Spain and lead author of the new study.

However, as the researchers were able to show, proboscideans were not always so diverse. In the first 30 million years of their history, the group was limited to Africa and Arabia, which together formed an isolated continent that was not connected to Asia as it is today. Until then, the evolution of these animals was quite slow and the few existing species were ecologically quite similar. But about 22 million years ago, Afro-Arabia connected with Eurasia and the proboscideans spread all over the world. The new challenges faced by the lineages scattered outside Afro-Arabia caused the ecology of the group to multiply. Species emerged with different, highly diverse tooth shapes, including strange, shovel-shaped tusks. "This ecological diversity reduced competition between species and allowed several of them to live together in the same ecosystem at the same time," points out Fernando Blanco, a researcher at the Museum für Naturkunde Berlin. This marked the beginning of the golden age of proboscideans. "If the link between Afro-Arabia and Eurasia had not happened, or had happened at a different time, the evolutionary history of proboscideans would have been radically different," Blanco adds.

The new study also revealed the factors that determined the group's ultimate decline. Seven million years ago, modern savannah ecosystems spread across all continents, and because of this change, many proboscideans adapted to life in forested areas disappeared. At the same time, however, new forms appeared that were able to feed on less nutritious plant material such as wood and especially grass, which is typical of savannas. Today's elephants are among these evolutionary newcomers.

About 3 million years ago, the rules of the game changed again with the onset of the ice ages. In Eurasia and Africa, the extinction rate quintupled. But as the researchers were able to show, the extinction rate rose even further in Eurasia and America 160,000 and 75,000 years ago, respectively. Were humans responsible for this debacle? "At that time, Homo sapiens had not yet made it to these continents," Cantalapiedra explains. The analyses showed that the different phases of extinction were linked to the decline and rapid fluctuations in global temperatures as a result of the ice ages. "The impact of our ancestors probably contributed to the extinction of the few surviving species, such as the woolly mammoth, a little later."

Boulder, Colo., USA: The Geological Society of America regularly publishes
articles online ahead of print. GSA Bulletin topics include
multiple articles about the dynamics of China and Tibet; the end-Permian
terrestrial extinction paradigm in South Africa; prehistoric lava flows
from the urban district of Catania (Etna volcano, Italy); the debated
origins of granite, and “a tale of two Tweefonteins.” You can find these
articles at

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

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Authigenic berthierine and incipient chloritization in shallowly buried
sandstone reservoirs: Key role of the source-to-sink context

Maxime Virolle; Benjamin Brigaud; Daniel Beaufort; Patricia Patrier; Eid
Abdelrahman ...

Abstract:
Chlorite is recognized worldwide as a key mineral that inhibits the
development of quartz cement in deeply buried sandstone reservoirs.
Iron-rich chlorite is mainly formed by the transformation of a precursor
clay mineral; however, few studies have focused on the early stages before
the crystallization of chlorite. This study analyzed shallowly buried
(400−1000 m) coastal sandstones from within the Wealden Group of the Paris
Basin. Berthierine, a 7 Å trioctahedral clay mineral belonging to the
serpentine group, approximatively with same chemistry as chlorite but a
different crystal structure, has been identified in a 900-m-deep well but
not in a 400−600-m-deep well. Berthierine has mainly been observed as clay
coatings around detrital grains with a typical honeycomb texture.
Nanopetrographic observations suggest that the honeycomb textural
organization of the clay particles found in deeper buried sandstone
reservoirs (>1500 m) is acquired from a berthierine precursor at shallow
depths. However, small amounts of quartz overgrowths are observed on the
surface of detrital grains at shallow depths and low temperature (below 40
°C), and it is believed that precursor berthierine coatings are primarily
responsible for the inhibition of quartz overgrowths before Fe-rich
chlorite is formed. This suggests that the key mineral primarily
controlling the reservoir quality of deeply buried sandstone reservoirs is
berthierine rather than iron-rich chlorite, which challenges the commonly
accepted assertion that chlorite coating is the main process that inhibits
quartz overgrowths. The source-to-sink context of the Paris Basin during
the Early Cretaceous was decisive with respect to the supply of sands and
berthierine clay precursors (in particular kaolinite and iron-rich,
hydroxy-interlayered clay minerals) to the center of the basin.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35865.1/605739/Authigenic-berthierine-and-incipient

Subduction initiation-induced rapid emplacement of garnet-bearing
peridotites at a nascent forearc: Petrological and Os-Li isotopic
evidence from the Purang ophiolite, Tibet

Xiao-Han Gong; Ji-Feng Xu; Ren-Deng Shi; Ben-Xun Su; Qi-Shuai Huang ...

Abstract:
Garnet-bearing peridotites commonly occur in the deeper parts of mature or
thickened oceanic lithosphere, and are rarely exhumed and emplaced onto the
seafloor. The Purang ophiolitic peridotites in south Tibet contain rare
symplectite pseudomorphs after garnet, offering a unique window into the
still poorly understood evolution of the deep oceanic lithosphere. Here,
integrated petrologic and Os-Li isotopic data are used to constrain the
evolution and dynamics of emplacement for these garnet peridotite
protoliths. The Purang peridotites show wide variations of chemical
compositions (spinel Cr#: 0.2−0.8) and Os model ages (up to 2.0 Ga), thus
representing a piece of heterogeneous oceanic mantle lithosphere. Dunite
channels show two distinctive groups of Cr# of spinels and Os-isotope
compositions, with the low- to medium-Cr# (0.2−0.6) and high-Cr# (0.7−0.8)
dunites reflecting the reaction of host lherzolites/harzburgites with
percolating mid-ocean ridge basalt−like and boninitic melts, respectively.
This confirms recent subduction initiation-related melt percolation in the
Purang peridotites. Coexisting olivines and pyroxenes in the peridotites
show systematic Li elemental and isotopic disequilibrium, suggesting fast
cooling of the peridotites to Li closure temperature shortly after the melt
percolations, likely during exhumation of the peridotites onto the
seafloor. This supports a close link between subduction initiation and
tectonic emplacement of the Purang peridotites. Combined with other
geological evidence, we suggest the Purang peridotites may originate from
the deep part of old, thick oceanic lithosphere of the Neo-Tethys. This
thick oceanic lithosphere was progressively weakened and thinned likely
during widespread plume-lithosphere interaction, triggering the
transformation of garnet peridotite protoliths to spinel peridotites.
Subsequently, initiation of a new subduction zone along the lithospheric
weakness caused rapid ascent and emplacement of the Purang peridotites at a
nascent forearc.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35960.1/604591/Subduction-initiation-induced-rapid-emplacement-of

A tale of two Tweefonteins: What physical correlation, geochronology,
magnetic polarity stratigraphy, and palynology reveal about the
end-Permian terrestrial extinction paradigm in South Africa

Robert A. Gastaldo; Johann Neveling; John W. Geissman; Sandra L. Kamo;
Cindy V. Looy

Abstract:
The contact between the Daptocephalus to Lystrosaurus declivis (previously Lystrosaurus)
Assemblage Zones (AZs) described from continental deposits of the Karoo
Basin was commonly interpreted to represent an extinction crisis associated
with the end-Permian mass-extinction event at ca. 251.901 ± 0.024 Ma. This
terrestrial extinction model is based on several sections in the Eastern
Cape and Free State Provinces of South Africa. Here, new stratigraphic and
paleontologic data are presented for the Eastern Cape Province, in
geochronologic and magnetostratigraphic context, wherein lithologic and
biologic changes are assessed over a physically correlated stratigraphy
exceeding 4.5 km in distance. Spatial variation in lithofacies demonstrates
the gradational nature of lithostratigraphic boundaries and depositional
trends. This pattern is mimicked by the distribution of vertebrates
assigned to the Daptocephalus and L. declivis AZs where
diagnostic taxa of each co-occur as lateral equivalents in landscapes
dominated by a Glossopteris flora. High-precision U-Pb zircon
(chemical abrasion-isotope dilution-thermal ionization mass spectrometry)
age results indicate maximum Changhsingian depositional dates that can be
used as approximate tie points in our stratigraphic framework, which is
supported by a magnetic polarity stratigraphy. The coeval nature of
diagnostic pre- and post-extinction vertebrate taxa demonstrates that the L. declivis AZ did not replace the Daptocephalus AZ
stratigraphically, that a biotic crisis and turnover likely is absent, and
a reevaluation is required for the utilization of these biozones here and
globally. Based on our data set, we propose a multidisciplinary approach to
correlate the classic Upper Permian localities of the Eastern Cape Province
with the Free State Province localities, which demonstrates their
time-transgressive nature.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35830.1/604557/A-tale-of-two-Tweefonteins-What-physical

Paleomagnetic dating of prehistoric lava flows from the urban district
of Catania (Etna volcano, Italy)

Andrea Magli; Stefano Branca; Fabio Speranza; Gilda Risica; Gaia Siravo ...

Abstract:
Determining the ages of past eruptions of active volcanoes whose slopes
were historically inhabited is vitally important for investigating the
relationships between eruptive phenomena and human settlements. During its
almost three-millennia-long history, Catania—the biggest city lying at the
toe of Etna volcano—was directly impacted only once by the huge lava flow
emplaced during the A.D. 1669 Etna flank eruption. However, other lava
flows reached the present-day Catania urban district in prehistoric ages
before the founding of the city in Greek times (729/728 B.C., i.e.,
2679/2678 yr B.P.). In this work, the Holocene lava flows of Barriera del
Bosco, Larmisi, and San Giovanni Galermo, which are exposed in the Catania
urban district, were paleomagnetically investigated at 12 sites (120
oriented cores). Paleomagnetic dating was obtained by comparing flow-mean
paleomagnetic directions to updated geomagnetic reference models for the
Holocene. The Barriera del Bosco flow turns out to represent the oldest
eruptive event and is paleomagnetically dated to the 11,234−10,941 yr B.P.
and 8395−8236 yr B.P. age intervals. The mean paleomagnetic directions from
the San Giovanni Galermo and Larmisi flows overlap when statistical
uncertainties are considered. This datum, along with geologic, geochemical,
and petrologic evidence, implies that the two lava flows can be considered
as parts of a single lava field that erupted in a narrow time window
between 5494 yr B.P. and 5387 yr B.P. The emplacement of such a huge lava
flow field may have buried several Neolithic settlements, which would thus
explain the scarce occurrence of archaeological sites of that age found
below the town of Catania.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B36026.1/602750/Paleomagnetic-dating-of-prehistoric-lava-flows

Migmatite and leucogranite in a continental-scale exhumed strike-slip
shear zone: Implications for tectonic evolution and initiation of
shearing

Junyu Li; Shuyun Cao; Xuemei Cheng; Franz Neubauer; Haobo Wang ...

Abstract:
Plutons within continental strike-slip shear zones bear important
geological processes on late-stage plate transpression and
continent-continent collision and associated lateral block extrusion.
Where, when, and how intrusions and shearing along transpressional
strike-slip shear zones respond to plate interactions, however, are often
debated. In this study, we investigated migmatite associated leucogranite
and pegmatite from the exhumed >1000-km-long Ailao Shan–Red River
left-lateral strike-slip shear zone in Southeast Asia that was active
during India-Eurasia plate convergence. Most zircons from the migmatites
and leucogranitic intrusions present inherited core-rim structure. The
depletion of rare earth element patterns and positive Eu anomalies suggest
that leucosomes and leucogranites are the result of crustal anatexis.
Zircon rims from the foliated migmatites and leucogranites record U-Pb ages
of 41−28 Ma, revealing the timing of the Cenozoic crustal anatexis event
along this strike-slip shear zone. Ages of the magmatic zircons from the
unfoliated pegmatites provide the timing of the termination of a
high-temperature tectono-thermal event and ductile left-lateral shearing at
26−23 Ma. The Cenozoic crustal anatexis along the Ailao Shan–Red River
strike-slip shear zone indicates that thickened crust underneath the shear
zone involved previously subducted crust. We propose that the Cenozoic
thermal state has an important effect on the crustal anatexis and thus on
the rheological behavior of the lithosphere by thermal weakening, which
plays an essential role in localizing the initiation of the deep-seated
lower-crustal shear zone.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35988.1/602751/Migmatite-and-leucogranite-in-a-continental-scale

The impact of a tear in the subducted Indian plate on the Miocene
geology of the Himalayan-Tibetan orogen

Rui Wang; Roberto F. Weinberg; Di-Cheng Zhu; Zeng-Qian Hou; Zhi-Ming Yang

Abstract:
The Yadong-Gulu Rift, cutting across the Gangdese belt and Himalayan
terranes, is currently associated with a thermal anomaly in the mantle and
crustal melting at 15−20 km depth. The rift follows the trace of a tear in
the underthrusted Indian continental lithospheric slab recognized by high
resolution geophysical methods. The Miocene evolution of a 400-km-wide band
following the trace of the tear and the rift, records differences
interpreted as indicative of a higher heat flow than its surroundings. In
the Gangdese belt, this band is characterized by high-Sr/Y granitic
magmatism that lasted 5 m.y. longer than elsewhere and by the highest
values of εHf(i) and association with the largest porphyry Cu-Mo
deposits in the Gangdese belt. Anomalously young magmatic rocks continue
south along the rift in the Tethyan and Higher Himalayas. Here, a
300-km-wide belt includes some of the youngest Miocene Himalayan
leucogranites; the only occurrence of mantle-derived mafic enclaves in a
leucogranite; young mantle-derived lamprophyre dikes; and the youngest and
hottest migmatites in the Higher Himalayas. These migmatites record a
history of rapid exhumation contemporaneous with the exhumation of Miocene
mafic eclogite blocks, which are unique to this region and which were both
heated to >800 °C at ca. 15−13 Ma, followed by isothermal decompression.
We suggest that the prominent tear in the Indian lithosphere, sub-parallel
to the rift, is the most likely source for these tectono-thermal anomalies
since the Miocene.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B36023.1/602752/The-impact-of-a-tear-in-the-subducted-Indian-plate

The timeline of prolonged accretionary processes in eastern Central
Asian Orogenic Belt: Insights from episodic Paleozoic intrusions in
central Inner Mongolia, North China

Lingling Yuan; Xiaohui Zhang; Zhili Yang

Abstract:
Updating magmatic profile in crucial constituent terranes across the
Central Asian Orogenic Belt presents a key to chronicling the timeline of
prolonged accretionary processes and termination of the Paleo-Asian Ocean
in the northern China−southern Mongolia tract. Here we performed a
systematic geochronological and geochemical study on a spectrum of
Paleozoic intrusions from the Erenhot region in central Inner Mongolia,
North China, within the hinterland of the tract, with four distinct
magmatic episodes unraveled. Combining these episodes with the previously
documented events from contiguous regions defines two major
tectono-magmatic cycles. The early Paleozoic cycle (500−450 Ma) evolved
from initial fluid-fluxed tholeiitic and calc-alkaline granitoids to
melt-fertilized mafic-intermediate magmatism. It appears to experience the
initiation and maturation of a Western Pacific-type intra-oceanic arc
system that culminated in ridge subduction. The late Paleozoic cycle
expanded in magmatic expression from sporadic Late Devonian (373−365 Ma)
calc-alkaline intermediate-felsic pulses through Early-Middle Carboniferous
(356−320 Ma) medium to high-K calc-alkaline flare-up to a Late
Carboniferous−Early Permian (310−277 Ma) province of diverse lithologies.
These magmatic episodes seem to encompass a complete active continental
arc−back-arc system that spanned from resuming oceanic plate subduction
through slab rollback and backarc rifting to ridge-trench collision and
backarc basin closure. Featuring a Rodinia-aged terrane affinity and a
representative Paleozoic magmatic profile, the Erenhot region provides an
optimal site for correlating the evolution of mosaic terranes in southern
Mongolia and northern China, and for evaluating the coupled evolution of
shifting tectonic regimes and plural crustal generation mechanisms within a
retreating accretionary orogen.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35907.1/602753/The-timeline-of-prolonged-accretionary-processes

Pure sediment-derived granites in a subduction zone

Jian Xu; Xiao-Ping Xia; Qiang Wang; Christopher J. Spencer; Chun-Kit Lai
...

Abstract:
The Earth is unique in the Solar System due to significant volumes of
granite in the lithosphere. However, the origins of granites are still
highly debated, especially sediment-derived granites, which are often
treated as a geochemical end-member of the continental crust. In the Yunnan
region of South China, we identify the occurrence of pure sediment-derived
granite in a subduction system. The suite of strongly peraluminous granite
reported herein is interpreted to represent pure metasedimentary melts
based on their whole-rock elemental and Sr-Nd-B and zircon Hf-O isotopic
compositions. These Late Permian−Early Triassic (ca. 254−248 Ma) granites
are characterized by radiogenically enriched Sr, Nd, and Hf isotopic
signatures. They show δ11B and δ18O signatures akin
to those of continental shales. Geochemical modeling indicates no
contributions from the mantle that can be detected. Considering the
regional tectonic evolution, these granites are suggested to be formed in a
subduction zone by decompression melting of rapidly exhumed back-arc
sediments. We posit that decompression melting was triggered by widespread
extension and thinning of the crust prompted by rollback of the subducting
oceanic crust. These granites thus provide evidence that granite formation
in subduction zones does not necessarily contribute to crustal growth.
These subduction-related pure sediment-derived granites have different
elemental ratios and contents (e.g., Al2O3/TiO 2 and Yb) from the Himalayan leucogranites. Considering their
source compositions (e.g., pelitic rocks), which are similar to those of
the Himalayan leucogranites, these differences are likely due to their
higher formation temperature and lower pressure despite a great similarity
in isotopic compositions. Identification of pure sediment-derived, strongly
peraluminous granites (SPGs) in subduction systems provides an important
geodynamic mechanism for crustal anatexis, which can both geochemically and
tectonically complement their collisional counterparts identified in the
Himalayas.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B36016.1/602698/Pure-sediment-derived-granites-in-a-subduction

Mafic-ultramafic intrusion formed by multi-stage evolution of hydrous
basaltic melts

Qi-Wei Li; Jun-Hong Zhao; Mei-Fu Zhou; Jian-Feng Gao

Abstract:
The magmatic processes beneath the active continental margins are very
complicated and affect structures and compositions of the arc roots.
Neoproterozoic igneous rocks are widely distributed around the margins of
the Tarim Block in NW China. The Xingdier mafic-ultramafic intrusion is a
composite body, located at the northern margin of the Tarim Block, and
consists of gabbro, pyroxenite, and peridotite units. The gabbro unit has a
secondary ion mass spectrometry zircon U-Pb age of 727 ± 5 Ma. Rocks from
the Xingdier intrusion have a large range of MgO (12.9−32.8 wt%) and SiO 2 (43.0−57.9 wt%), and low K2O+Na2O
(0.11−2.25 wt%) contents. They have right inclined chondrite-normalized
rare earth element patterns with (La/Yb)N ratios of 2.2−8.6.
Their primitive mantle normalized trace element patterns show arc-affinity
geochemical features characterized by enrichment in Rb, Ba, Th, U, and Pb
and depletion in Nb, Ta, and Ti. They have variable initial 87
Sr/86Sr ratios (0.7063−0.7093), εNd(t) values (−2.9 to −7.8),206Pb/204Pb (17.08−17.80), 207Pb/ 204Pb (15.42−15.49), and 208Pb/204Pb
ratios (37.48−38.05), forming an evolution trend from the peridotite unit
to the gabbro and pyroxenite units. Clinopyroxene in the three units is
chemically similar to those formed in hydrous magmas. The spinel inclusions
in olivine from the peridotite unit show unmixing texture and have high Al
contents and oxygen fugacity of ∼FMQ+1. Therefore, the parental magma was
probably derived from a lithospheric mantle enriched by slab-derived
fluids. Rocks from the gabbro and peridotite units are proposed to have
been derived from olivine-normative melts, whereas rocks from the
pyroxenite unit are cumulates from the quartz-normative melts. Such
contrasting parental magmas resulted from variable degrees of crustal
contamination and fractional crystallization in the arc root.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35920.1/601081/Mafic-ultramafic-intrusion-formed-by-multi-stage

Origin of syn-collisional granitoids in the Gangdese orogen: Reworking
of the juvenile arc crust and the ancient continental crust

Yu-Wei Tang; Long Chen; Zi-Fu Zhao; Yong-Fei Zheng

Abstract:
Granitoids at convergent plate boundaries can be produced either by partial
melting of crustal rocks (either continental or oceanic) or by fractional
crystallization of mantle-derived mafic magmas. Whereas granitoid formation
through partial melting of the continental crust results in reworking of
the pre-existing continental crust, granitoid formation through either
partial melting of the oceanic crust or fractional crystallization of the
mafic magmas leads to growth of the continental crust. This category is
primarily based on the radiogenic Nd isotope compositions of crustal rocks;
positive εNd(t) values indicate juvenile crust whereas negative
εNd(t) values indicate ancient crust. Positive εNd(t)
values are common for syn-collisional granitoids in southern Tibet, which
leads to the hypothesis that continental collision zones are important
sites for the net growth of continental crust. This hypothesis is examined
through an integrated study of in situ zircon U-Pb ages and Hf isotopes,
whole-rock major trace elements, and Sr-Nd-Hf isotopes as well as mineral O
isotopes for felsic igneous rocks of Eocene ages from the Gangdese orogen
in southern Tibet. The results show that these rocks can be divided into
two groups according to their emplacement ages and geochemical features.
The first group is less granitic with lower SiO2 contents of
59.82−64.41 wt%, and it was emplaced at 50−48 Ma in the early Eocene. The
second group is more granitic with higher SiO2 contents of
63.93−68.81 wt%, and it was emplaced at 42 Ma in the late Eocene. The early
Eocene granitoids exhibit relatively depleted whole-rock Sr-Nd-Hf isotope
compositions with low (87Sr/86Sr)i ratios
of 0.7044−0.7048, positive εNd(t) values of 0.6−3.9, ε Hf(t) values of 6.5−10.5, zircon εHf(t) values of
1.6−12.1, and zircon δ18O values of 5.28−6.26‰. These isotopic
characteristics are quite similar to those of Late Cretaceous mafic arc
igneous rocks in the Gangdese orogen, which indicates their derivation from
partial melting of the juvenile mafic arc crust. In comparison, the late
Eocene granitoids have relatively lower MgO, Fe2O3,
Al2O3, and heavy rare earth element (HREE) contents
but higher K2O, Rb, Sr, Th, U, Pb contents, Sr/Y, and (La/Yb) N ratios. They also exhibit more enriched whole-rock Sr-Nd-Hf
isotope compositions with high (87Sr/86Sr) i ratios of 0.7070−0.7085, negative εNd(t) values of
−5.2 to −3.9 and neutral εHf(t) values of 0.9−2.3, and
relatively lower zircon εHf(t) values of −2.8−8.0 and slightly
higher zircon δ18O values of 6.25−6.68‰. An integrated
interpretation of these geochemical features is that both the juvenile arc
crust and the ancient continental crust partially melted to produce the
late Eocene granitoids. In this regard, the compositional evolution of
syn-collisional granitoids from the early to late Eocene indicates a
temporal change of their magma sources from the complete juvenile arc crust
to a mixture of the juvenile and ancient crust. In either case, the
syn-collisional granitoids in the Gangdese orogen are the reworking
products of the pre-existing continental crust. Therefore, they do not
contribute to crustal growth in the continental collision zone.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35928.1/601082/Origin-of-syn-collisional-granitoids-in-the

Mantle source of tephritic porphyry in the Tarim Large Igneous Province
constrained from Mg, Zn, Sr, and Nd isotope systematics: Implications
for deep carbon cycling

Weiliang Kong; Zhaochong Zhang; Zhiguo Cheng; Bingxiang Liu; M. Santosh ...

Abstract:
The nature and source of magmatism associated with large igneous provinces
(LIPs) remain disputed. Here we investigate the role of recycled materials
that contributed to mantle heterogeneity in the Tarim Large Igneous
Province (TLIP) in China through integrated Zn−Mg−Sr−Nd isotopes of a rare
tephritic rock suite. The Sr−Nd isotopes [(87Sr/86Sr)i = 0.70368−0.70629; εNd(t) = −0.25−4.64] and δ 26Mg values (−0.23‰ to −0.34‰) of the tephritic porphyries are
consistent with a normal mantle origin. In contrast, the whole rock and
pyroxene phenocrysts yield δ66Zn values of +0.28‰ to +0.46‰ and
+0.30‰ to +0.39‰, which are slightly heavier than those of the terrestrial
mantle (+0.16 ± 0.06‰) and mid-oceanic-ridge basalts (MORBs) (+0.27 ±
0.05‰). We exclude the possibility that the heavy Zn isotopes of the
Wajilitag tephritic porphyries are caused by magmatic processes such as
fractional crystallization and partial melting and correlate the isotopic
features to the role of altered oceanic crust along with magnesite in the
mantle source. The Wajilitag tephritic porphyry displays trace-element
patterns similar to those of the melts from natural hornblendite,
especially those of hornblendite + peridotite. Additionally, the
geochemical characteristics such as enrichment in Nb and Ta, depletion in
K, high TiO2, and constant Na2O/K2O ratios
also suggest that the tephritic porphyries were derived from an
amphibole-bearing source contributed by altered oceanic crust along with
sedimentary carbonates. Our study provides insight into the contribution of
subducted materials to the mantle heterogeneity beneath the TLIP and
highlights the role of subduction in the deep carbon cycle and subducted
slab-lithosphere-plume interaction in the generation of LIPs.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35902.1/600886/Mantle-source-of-tephritic-porphyry-in-the-Tarim

Sedimentology, geochronology, and provenance of the late Cenozoic
“Yangtze Gravel”: Implications for Lower Yangtze River reorganization
and tectonic evolution in southeast China

Ping Wang; Hongbo Zheng; Yongdong Wang; Xiaochun Wei; Lingyu Tang ...

Abstract:
The evolution of the Yangtze River, the longest river in Asia, provides a
spectacular example for understanding the Cenozoic interaction between
tectonics, climate, and surficial processes. The oldest Lower Yangtze
deposits, characterized by ∼100-m-thick sequences of unconsolidated
conglomerate, sandstone, and siltstone, referred to as “Yangtze Gravel,”
have been recently dated >23 Ma, indicating a pre-Miocene establishment
of a through-going river. However, the link between river integration and
tectonic evolution has never been established due to the limited study of
these sediments. Here, we report sedimentology, geochronology, and
provenance of the Yangtze Gravel based on 17 stratigraphic sections exposed
along the Lower Yangtze River. Our new chronostratigraphic results,
including 40Ar/39Ar ages from the overlying basalt and fossil-based
stratigraphic correlation, suggest an early-middle Miocene age for these
sediments. Detailed analysis of lithofacies reveals several sequences of
coarse-grained channel-belt deposits (channel fills and bars), indicating
braided alluvial deposition across the Jianghan Basin, North Jiangsu-South
Yellow Sea Basin, and East China Sea Shelf Basin. This ancient Lower
Yangtze River is further characterized by petrography and detrital zircon
U-Pb geochronology results which show similar provenance and erosion
pattern as the present-day Yangtze River. However, the ancient river in
early-middle Miocene is an alluvial, bedload-dominated braided river with
higher stream power and a more prolonged course flowing into the East China
Sea Shelf Basin. These differences between ancient and modern Lower Yangtze
River reflect varied climate and paleogeography in southeast China during
the late Cenozoic. Compared with the Paleogene red-colored, halite-bearing,
Ephedripite pollen-dominated, lacustrine deposits in Jianghan Basin and
North Jiangsu-South Yellow Sea Basin, the deposition of yellow to
green-colored, coarse-grained, arboreal pollen, and wood-dominated Yangtze
Gravel indicates a drainage reorganization from hydrologically closed lakes
to a through-going river system during late Oligocene to early Miocene.
During Paleogene, rift basins were filled by alluvial and
fluvial-lacustrine deposition with restricted flow distance and local
sources. From late Oligocene to early-middle Miocene, the post-rift
subsidence opens a path for the ancient Lower Yangtze River connecting the
Jianghan Basin, North Jiangsu-South Yellow Sea Basin, and East China Sea
Shelf Basin. We attribute the drainage reorganization of the Lower Yangtze
River to be a surficial response to Cenozoic tectonics, particularly the
western Pacific subduction, in southeast China. The deposition of the
widespread, coarse-grained Yangtze Gravel is probably due to the combined
effects of catchment expansion and strong monsoonal climate in East Asia.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35851.1/600887/Sedimentology-geochronology-and-provenance-of-the

Thermotectonic events recorded by U-Pb geochronology and Zr-in-rutile
thermometry of Ti oxides in basement rocks along the P2 fault, eastern
Athabasca Basin, Saskatchewan, Canada

E. Adlakha; K. Hattori

Abstract:
Basement rocks below the Athabasca Basin, Saskatchewan, have been intensely
altered through paleoweathering and multiple hydrothermal events, including
the formation of world-class unconformity-type uranium deposits. Here, we
demonstrate the utility of Ti-oxide thermochronology for identifying
thermotectonic events in these altered rocks leading to uranium
mineralization along basement structures. Rutile grains along the P2 fault,
a major fault in the eastern Athabasca Basin, exhibit 207Pb/ 206Pb ages of ca. 1850−1700 Ma, with a weighted mean of 1757 ± 6
Ma (mean square of weighted deviation [MSWD] = 1.4, n = 116). The
older ages (~1770 Ma) record regional metamorphism reaching a
temperature of 875 °C during the Trans-Hudson orogeny. Pb diffusion
modeling indicates that metamorphic rutile should exhibit cooling ages of
1760−1750 Ma. Rutile grains showing young ages, ~1750 Ma, reflect
isotopic resetting during regional asthenospheric upwelling between 1770
and 1730 Ma related to the emplacement of the Kivalliq igneous suite to the
north. This thermotectonic event (temperature ~550 °C) promoted
hydrothermal activity to produce silicified rocks, i.e., “quartzite,” along
the P2 fault, which later focused mineralizing fluids for unconformity-type
uranium deposits. The young rutile ages also indicate that the basement
rocks remained hot until 1700 Ma, providing the maximum age for the
deposition of the Athabasca sediments. Anatase yields a concordia age of
1569 ± 31 Ma (MSWD = 0.30, n = 5), which is within uncertainty of
the oldest ages for uraninite of the McArthur River deposit. This age
corresponds to the incursion of basinal fluids in the basement along the P2
fault during uranium mineralization.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35820.1/600747/Thermotectonic-events-recorded-by-U-Pb

Superposition of Cretaceous and Cenozoic deformation in northern Tibet:
A far-field response to the tectonic evolution of the Tethyan orogenic
system

Ye Wang; Xuanhua Chen; Yaoyao Zhang; Zheng Yin; Andrew V. Zuza ...

Abstract:
Although the Cenozoic Indo-Asian collision is largely responsible for the
formation of the Tibetan plateau, the role of pre-Cenozoic structures in
controlling the timing and development of Cenozoic deformation remains
poorly understood. In this study we address this problem by conducting an
integrated investigation in the northern foreland of the Tibetan plateau,
north of the Qilian Shan-Nan Shan thrust belt, NW China. The work involves
field mapping, U-Pb detrital-zircon dating of Cretaceous strata in the
northern foreland of the Tibetan plateau, examination of growth-strata
relationships, and construction and restoration of balanced cross sections.
Our field mapping reveals multiple phases of deformation in the area since
the Early Cretaceous, which was expressed by northwest-trending folding and
northwest-striking thrusting that occurred in the early stages of the Early
Cretaceous. The compressional event was followed immediately by extension
and kinematically linked right-slip faulting in the later stage of the
Early Cretaceous. The area underwent gentle northwest-trending folding
since the late Miocene. We estimate the magnitude of the Early Cretaceous
crustal shortening to be ∼35%, which we interpret to have resulted from a
far-field response to the collision between the Lhasa and the Qiangtang
terranes in the south. We suggest that the subsequent extension in the
Early Cretaceous was induced by orogenic collapse. U-Pb dating of detrital
zircons, sourced from Lower Cretaceous sedimentary clasts from the north
and the south, implies that the current foreland region of the Tibetan
plateau was a topographic depression between two highland regions in the
Early Cretaceous. Our work also shows that the Miocene strata in the
foreland region of the northern Tibetan plateau was dominantly sourced from
the north, which implies that the rise of the Qilian Shan did not impact
the sediment dispersal in the current foreland region of the Tibetan
plateau where this study was conducted.

View article:

https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35944.1/600737/Superposition-of-Cretaceous-and-Cenozoic

WILMINGTON, Del. (June 29, 2021) - A new report finds that 509,025 (9.17%) public high school students in 24 states experienced homelessness in spring 2019 -- three times the number recognized by the states' education agencies. This under-recognition creates gaps in funding and services needed by this vulnerable population.

Researchers from Nemours Children's Health and the University of Pennsylvania analyzed data from the Centers for Disease Control and Prevention (CDC) for public schools across 24 states and 12 school districts. During spring 2019, more than 9% of public high school students experienced homelessness during a 30-day period in the 24 states. The rate was even higher in the 12 school districts, analyzed separately, where nearly 14% of students reported homelessness.

The report's authors believe the discrepancy between the CDC's data, collected through the Youth Risk Behavior Surveillance System (YRBSS), and the state and local school agency homelessness estimates is likely due to the more comprehensive nature and complex sampling design of the YRBSS. The YRBSS is an anonymous set of surveys conducted in public high schools every two years. The report analyzed data from all states and school districts that opted to ask about student housing and homelessness for the 2019 YRBSS.

Homelessness was more likely among students who were male, LGBT (lesbian, gay, bisexual, transgender), Black/African American, Hispanic/Latinx, or Native American/Hawaiian. Students who experienced homelessness reported higher rates of sexual victimization, physical victimization, and having been bullied. Even when controlling for other risk factors, students who experienced homelessness reported higher rates of severe suicidality, hard drug use, alcohol abuse, risky sexual behavior, and poor grades.

"Even before the COVID-19 pandemic, we saw high rates of homelessness in public high school students and strong links between homelessness and other harmful experiences," said the report's lead author, Danielle Hatchimonji, PhD, of Nemours' Center for Healthcare Delivery Science. "The pandemic's impact on financial and housing stability will have even broader, ripple effects on mental health and academic functioning -- effects that will continue to disproportionately harm students of color."

Dan Treglia, PhD, of the University of Pennsylvania, a co-author on the report and a homelessness expert, explained, "The CDC housing data let us fully recognize the magnitude and depth of youth homelessness in the United States. By acknowledging its extent, we can begin to address the underlying problems and continue to improve systems to identify and serve these students across local school districts and states."

The report makes several recommendations, including prioritizing funding for the federal McKinney-Vento education programs designed to identify and address student homelessness and better sharing of information across service sectors, including housing, education, substance abuse, and mental health. The report also emphasizes the need to reduce poverty and systemic racism and heterosexism, which place students from marginalized groups at higher risk of homelessness.

Hatchimonji added, "That any student experiences homelessness is unacceptable. That homelessness is so much more common among students of color and LGBT students underscores our shared obligation to promote equity and safety, especially for basic needs and human rights."

"We know from other studies that many students who experience homelessness show resilience," said senior author J. J. Cutuli, PhD, of Nemours' Center for Healthcare Delivery Science. "We also know that resilience happens because of relationships and other supports in their lives. Promoting resilience means supporting families, educators, and others in the lives of teens who make sure homelessness does not get in the way."

A study by Stanford University School of Medicine investigators hints that people with COVID-19 may experience milder symptoms if certain cells of their immune systems "remember" previous encounters with seasonal coronaviruses -- the ones that cause about a quarter of the common colds kids get.

These immune cells are better equipped to mobilize quickly against SARS-CoV-2, the coronavirus responsible for COVID-19, if they've already met its gentler cousins, the scientists concluded.

The findings may help explain why some people, particularly children, seem much more resilient than others to infection by SARS-CoV-2, the coronavirus that causes COVID-19. They also might make it possible to predict which people are likely to develop the most severe symptoms of COVID-19.

The immune cells in question, called killer T cells, roam through the blood and lymph, park in tissues and carry out stop-and-frisk operations on resident cells. The study, published online July 1 in Science Immunology, showed that killer T cells taken from the sickest COVID-19 patients exhibit fewer signs of having had previous run-ins with common-cold-causing coronaviruses.

Discussions about immunity to COVID-19 often center on antibodies -- proteins that can latch onto a virus before it's able to infect a vulnerable cell. But antibodies are easily fooled, said Mark Davis, PhD, a professor of microbiology and immunology; director of Stanford's Institute for Immunity, Transplantation and Infection; and a Howard Hughes Medical Institute investigator. Davis is the study's senior author.

"Pathogens evolve quickly and 'learn' to hide their critical features from our antibodies," said Davis, who is also the Burt and Marion Avery Family Professor. But T cells recognize pathogens in a different way, and they're tough to fool.

Our cells all issue real-time reports on their inner state of affairs by routinely sawing up some samples of each protein they've made lately into tiny pieces called peptides and displaying those peptides on their surfaces for inspection by T cells.

When a killer T-cell's receptor notices a peptide on a cell's surface that doesn't belong there -- for example, it's from a protein produced by an invading microorganism -- the T cell declares war. It multiplies furiously, and its numerous offspring -- whose receptors all target the same peptide sequence -- fire up to destroy any cell carrying these telltale-peptide indications of that cell's invasion by a pathogenic microbe.

Some of the original killer T cell's myriad daughter cells enter a more placid state, remaining above the fray. These "memory T cells" exhibit heightened sensitivity and exceptional longevity. They persist in the blood and lymph often for decades, ready to spring into action should they ever cross paths with the peptide that generated the wave of T-cell expansion that begat them. That readiness can save valuable time in stifling a previously encountered virus or a close cousin.

As the pandemic progressed, Davis mused: "A lot of people get very sick or die from COVID-19, while others are walking around not knowing they have it. Why?"

To find out, the study's first author, postdoctoral fellow Vamsee Mallajosyula, PhD, first confirmed that some portions of SARS-CoV-2's sequence are effectively identical to analogous portions of one or more of the four widespread common-cold-causing coronavirus strains. Then he assembled a panel of 24 different peptide sequences that were either unique to proteins made by SARS-CoV-2 or also found on similar proteins made by one or more (or even all) of the seasonal strains.

The researchers analyzed blood samples taken from healthy donors before the COVID-19 pandemic began, meaning they'd never encountered SARS-CoV-2 -- although many presumably had been exposed to common-cold-causing coronavirus strains. The scientists determined the numbers of T cells targeting each peptide represented in the panel.

They found that unexposed individuals' killer T cells targeting SARS-CoV-2 peptides that were shared with other coronaviruses were more likely to have proliferated than killer T cells targeting peptides found only on SARS-CoV-2. The T cells targeting those shared peptide sequences had probably previously encountered one or another gentler coronavirus strain -- and had proliferated in response, Davis said.

Many of these killer T cells were in "memory" mode, he added.

"Memory cells are by far the most active in infectious-disease defense," Davis said. "They're what you want to have in order to fight off a recurring pathogen. They're what vaccines are meant to generate."

Killer T cells whose receptors target peptide sequences unique to SARS-CoV-2 must proliferate over several days to get up to speed after exposure to the virus, Davis said. "That lost time can spell the difference between never even noticing you have a disease and dying from it," he said.

To test this hypothesis, Davis and his colleagues turned to blood samples from COVID-19 patients. They found that, sure enough, COVID-19 patients with milder symptoms tended to have lots of killer-T memory cells directed at peptides SARS-CoV-2 shared with other coronavirus strains. Sicker patients' expanded killer T-cell counts were mainly among those T cells typically targeting peptides unique to SARS-CoV-2 and, thus, probably had started from scratch in their response to the virus.

"It may be that patients with severe COVID-19 hadn't been infected, at least not recently, by gentler coronavirus strains, so they didn't retain effective memory killer T cells," Davis said.

Davis noted that cold-causing seasonal coronavirus strains are rampant among children, who rarely develop severe COVID-19 even though they're just as likely to get infected as adults are.

"Sniffles and sneezes typify the daycare setting," he said, "and coronavirus-caused common colds are a big part of the reason. As many as 80% of kids in the United States get exposed within the first couple of years of life."

Davis and Mallajosyula have filed, through Stanford's Office of Technology Licensing, for patents on the technology used in this study.

Davis is a member of Stanford Bio-X, the Stanford Cardiovascular Institute, the Stanford Maternal and Child Health Research Institute, the Stanford Cancer Institute and the Stanford Wu Tsai Neurosciences Institute.

In a new Editorial, Peter Heeger, Christian Larsen, and Dorry Segev discuss recent evidence - including a recent Science Immunology study by Hector Rincon-Arevalo and colleagues - that points to a diminished immune response to COVID-19 vaccines among organ transplant recipients and others on immunosuppressive drug regimens. The authors note that this presents challenges at both the individual and population levels, since current vaccine protocols may not provide adequate protection to immunosuppressed patients - who could, in turn, become reservoirs for new and dangerous variants of the virus. As such, Heeger, Larsen, and Segev argue that developing vaccination strategies for transplant recipients should be a high priority in the next wave of research focused on fighting COVID-19. "The global scientific response to the SARS-CoV-2 pandemic has been a marvel," the researchers write. "But vulnerable populations remain, and there is no time to rest in the last mile. The full force of scientific effort is still needed to provide immune protection for those who remain at risk from this deadly virus and to control the reservoir to prevent fertile fields for mutations that put the entire population at risk."

ROCHESTER, Minn. -- Research by investigators at Mayo Clinic Cancer Center suggests that physicians should screen patients with lung cancer for MET amplification/overexpression before determining a treatment strategy. Their findings are published Cancer Discovery, a journal of the American Association for Cancer Research.

"In our research we found several lung cancer cases that were not responsive to standard chemotherapy," says Zhenkun Lou, Ph.D., a cancer researcher at Mayo Clinic. "Because these lung cancers were positive for PD-L1, a protein that allows some cells to escape attack by the immune system, we then tried treating these patients with anti-PD1 immunotherapy to relieve PD-L1 mediated immune suppression, however this treatment also failed."

Dr. Lou and his colleagues then used cell line animal models and patient tissue samples to study why these lung cancers were not responding to treatment.

"We discovered that in these particular cases, the cancer exhibited a MET oncogene amplification, which creates a hostile environment for immunotherapy," says Dr. Lou. Abnormal MET activation has been implicated as an oncogenic driver in non-small-cell lung cancer.

After analyzing several independent medical databases, Dr. Lou and his colleagues confirmed that MET oncogene amplification should be a factor to be considered when designing lung cancer therapy. In addition, they showed that in animal models, a combination of a MET inhibitor with anti-PD1 immunotherapy was effective in treating cancers with MET amplification.

"Our study suggests that patients with a MET oncogene amplification will not respond to immunotherapy alone and will require treatment with a combination of a MET inhibitor together with immunotherapy," says Dr. Lou. He cautions that this strategy will require confirmation in a prospective clinical trial before becoming a standard of care. In the meantime, Dr. Lou suggests that patients with lung cancer be screened for MET amplification/overexpression before determining an immunotherapy strategy.

A key factor in America's prodigious agricultural output turns out to be something farmers can do little to control: clean air. A new Stanford-led study estimates pollution reductions between 1999 and 2019 contributed to about 20 percent of the increase in corn and soybean yield gains during that period - an amount worth about $5 billion per year.

The analysis, published this week in Environmental Research Letters, reveals that four key air pollutants are particularly damaging to crops, and accounted for an average loss of about 5 percent of corn and soybean production over the study period. The findings could help inform technology and policy changes to benefit American agriculture, and underscore the value of reducing air pollution in other parts of the world.

"Air pollution impacts have been hard to measure in the past, because two farmers even just 10 miles apart can be facing very different air quality. By using satellites, we were able to measure very fine scale patterns and unpack the role of different pollutants," said study lead author David Lobell, the Gloria and Richard Kushel Director of the Center on Food Security and the Environment.

The research highlights the considerable power of satellites to illuminate pollution impacts at a scale not possible otherwise. That power could be of even greater value in countries with less access to air monitors and yield data.

Reading the air

Scientists have long known that air pollution is toxic to plant life in high doses, but not how much farmers' yields are actually hurt at current levels. The impact of pollution on agriculture overall, as well as the effects of individual pollutants, has also remained unknown.

Focusing on a nine-state region (Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio, South Dakota and Wisconsin) that produces roughly two-thirds of national maize and soybean output, Lobell and study co-author Jennifer Burney, an associate professor of environmental science at the University of California, San Diego, set out to measure the impact on crop yields of ozone, particulate matter, nitrogen dioxide and sulfur dioxide.

Ozone is the result of heat and sunlight-driven chemical reactions between nitrogen and hydrocarbons, such as those found in car exhaust. Particulate matter refers to large particles of dust, dirt, soot or smoke. Nitrogen dioxide and sulfur dioxide are gases released into the atmosphere primarily through the burning of fossil fuels at power plants and other industrial facilities.

"This has been a tricky problem to untangle because historically our measurements of different types of air pollutants and our measurements of agricultural yields haven't really overlapped spatially at the necessary resolution," explained Burney. "With the new high spatial resolution data, we could look at crop yields near both pollution monitors and known pollutant emissions sources. That revealed evidence of different magnitudes of negative impacts caused by different pollutants."

Lobell and Burney extended their analysis back to 1990, when Congress passed Clean Air Act amendments that resulted in significant air quality improvements across the country. The researchers looked through air pollution data from hundreds of monitoring stations around the region, federal data on power plant emissions, satellite-based observations of nitrogen dioxide around those power plants, crop yield data from federal surveys and satellite imagery, as well as weather data to account for growing season conditions known to explain crop yield variations.

Surprising findings

What Lobell and Burney discovered surprised them. Among their findings: negative effects of each of the four pollutants on corn and soybean yields, and a clear yield increase the farther away from power plants - particularly coal-burning facilities - crops were grown. The unique spatial patterns of each pollutant allowed them to disentangle the effect of each pollutant in a way that past studies could not.

The researchers estimated that total yield losses from the four pollutants averaged 5.8 percent for maize and 3.8 percent for soybean over the past two decades. Those losses declined over time as the air grew cleaner. In fact, the reduction in air pollution contributed to an estimated 4 percent growth in corn yields and 3 percent growth in soybean yields - increases that equal 19 percent of corn's overall yield gains during the timeframe and 23 percent of soybeans' overall yield gains.

"We already know that the Clean Air Act resulted in trillions of dollars of benefits in terms of human health, so I think of these billions in agricultural benefits as icing on the cake," Lobell said. "But even if it's a small part of the benefits of clear air, it has been a pretty big part of our ability to continue pushing agricultural productivity higher."

The number of people who live past the age of 100 has been on the rise for decades, up to nearly half a million people worldwide.

There are, however, far fewer “supercentenarians,” people who live to age 110 or even longer. The oldest living person, Jeanne Calment of France, was 122 when she died in 1997; currently, the world’s oldest person is 118-year-old Kane Tanaka of Japan.

Such extreme longevity, according to new research by the University of Washington, likely will continue to rise slowly by the end of this century, and estimates show that a lifespan of 125 years, or even 130 years, is possible.

“People are fascinated by the extremes of humanity, whether it’s going to the moon, how fast someone can run in the Olympics, or even how long someone can live,” said lead author Michael Pearce, a UW doctoral student in statistics. “With this work, we quantify how likely we believe it is that some individual will reach various extreme ages this century.”

Longevity has ramifications for government and economic policies, as well as individuals’ own health care and lifestyle decisions, rendering what’s probable, or even possible, relevant at all levels of society.

The new study, published June 30 in Demographic Research, uses statistical modeling to examine the extremes of human life. With ongoing research into aging, the prospects of future medical and scientific discoveries and the relatively small number of people to have verifiably reached age 110 or older, experts have debated the possible limits to what is referred to as the maximum reported age at death. While some scientists argue that disease and basic cell deterioration lead to a natural limit on human lifespan, others maintain there is no cap, as evidenced by record-breaking supercentenarians.

Pearce and Adrian Raftery, a professor of sociology and of statistics at the UW, took a different approach. They asked what the longest individual human lifespan could be anywhere in the world by the year 2100. Using Bayesian statistics, a common tool in modern statistics, the researchers estimated that the world record of 122 years almost certainly will be broken, with a strong likelihood of at least one person living to anywhere between 125 and 132 years.

To calculate the probability of living past 110 — and to what age — Raftery and Pearce turned to the most recent iteration of the International Database on Longevity, created by the Max Planck Institute for Demographic Research. That database tracks supercentenarians from 10 European countries, plus Canada, Japan and the United States.

Using a Bayesian approach to estimate probability, the UW team created projections for the maximum reported age at death in all 13 countries from 2020 through 2100.

Among their findings:

Researchers estimated near 100% probability that the current record of maximum reported age at death — Calment’s 122 years, 164 days — will be broken;
The probability remains strong of a person living longer, to 124 years old (99% probability) and even to 127 years old (68% probability);
An even longer lifespan is possible but much less likely, with a 13% probability of someone living to age 130;
It is “extremely unlikely” that someone would live to 135 in this century.

As it is, supercentenarians are outliers, and the likelihood of breaking the current age record increases only if the number of supercentenarians grows significantly. With a continually expanding global population, that’s not impossible, researchers say.

People who achieve extreme longevity are still rare enough that they represent a select population, Raftery said. Even with population growth and advances in health care, there is a flattening of the mortality rate after a certain age. In other words, someone who lives to be 110 has about the same probability of living another year as, say, someone who lives to 114, which is about one-half.

“It doesn’t matter how old they are, once they reach 110, they still die at the same rate,” Raftery said. “They’ve gotten past all the various things life throws at you, such as disease. They die for reasons that are somewhat independent of what affects younger people.

“This is a very select group of very robust people.”

In Canada, low-income hospital patients under palliative care are less likely to receive medical assistance in dying compared to those who are high income, according to a study published in British Medical Journal Open (BMJ Open).

Medical assistance in dying (MAID) is legal and free under Medicare, Canada's universal health care system. Patients with low socioeconomic status (SES), however, generally tend to experience less access to medical care compared to their high SES counterparts.

Eldar Shafir, professor of psychology and public affairs at the Princeton School of Public and International Affairs, along with a team of researchers from Sunnybrook Hospital in Ontario, investigated whether this trend of decreased care for low-income patients includes medical assistance in dying.

"I have long been interested in SES influences on decision-making," said Shafir. "I often discuss with my friend and collaborator, Dr. Redelmeier, ways to illustrate some of our findings in the medical realm, especially, when possible, among experts. ... In this case MAID was a really interesting domain, since it's a 'big' decision, and finances are not an issue."

Medical assistance in dying was ruled legal in Canada in February 2015 and officially implemented and covered under Medicare by June 2016. To be considered, a patient must have a grievous and irremediable medical condition, such as metastatic cancer, that causes unbearable suffering where death is foreseeable, according to the Government of Canada.

However, one's socioeconomic status can influence how medical care is administered and received by a patient in several ways. "People can be easily susceptible to pitfalls and biases in reasoning," Shafir said.

Low-income patients, for example, may feel less equipped to advocate for their care and to convey dissatisfaction. Clinicians can also succumb to the "thick-skin fallacy," or the harmful perception that low-income people are used to hardship and therefore less impacted by it.

The team explored the association between socioeconomic status and medical assistance in dying by identifying hospital patients aged 65 and older in Ontario, Canada between June 2016 and 2019. At the time of their death, all patients, all of whom had serious medical conditions, were under palliative care, receiving pain-relieving treatment for symptoms. They were then divided into groups based on socioeconomic status, which was calculated using an official algorithm created by Statistics Canada based on home neighborhood location, and whether they received medical assistance in dying.

During the three years, 50,096 patients were given palliative care in their last month of life. Among them, 920 received medical assistance in dying. Only 1.5% of low-income patients identified were given MAID, compared to 2.4% of high-income patients -- a 39% decreased likelihood for those with low socioeconomic status. This disparity in care was found consistently across a variety of patient subgroups that varied in age, sex, home location, type of cancer, health care utilization, and general frailty. It was even replicated with patients treated by the same responsible physician.

The study's results support past findings by other countries about the relationship between medical assistance in dying and patients' socioeconomic status. In countries like the United States, the Netherlands, Switzerland, and Belgium, people who received MAID or MAID equivalents tended to be highly educated, financially secure, or live in wealthy neighborhoods.

The researchers, however, suspect that this difference in patient care may be influenced by factors that exist outside of financial capabilities. "I suspect most of what happens here is a function of the doctor-patient interaction," explained Shafir. "I think, all else equal, that doctors might see low-SES patients as less in urgent need of MAID."

Certain study limitations, such as biased and imperfect socioeconomic status measures, warrant further research exploring the link between social class and medically assisted death. "Both perspectives, the doctors' and the patients', need to be better understood by the medical community in order to provide low-SES patients with same care afforded those of higher SES," said Shafir.

The observations made by Shafir and his team address an earlier misconception in Canada that medical assistance in dying may harmfully target low-income individuals. The researchers are optimistic that their findings may help promote greater patient-clinician communication and engagement.

LA JOLLA, CA--Researchers at La Jolla Institute for Immunology (LJI) have found that T cells from people who have recovered from COVID-19 or received the Moderna or Pfizer-BioNTech vaccines are still able to recognize several concerning SARS-CoV-2 variants.

Their new study, published online on July 1, 2021 in Cell Reports Medicine, shows that both CD4+ "helper" T cells and CD8+ "killer" T cells can still recognize mutated forms of the virus. This reactivity is key to the body's complex immune response to the virus, which allows the body to kill infected cells and stop severe infections.

"This study suggests that the impact of mutations found in the variants of concern is limited," says LJI Professor Alessandro Sette, Dr.Bio.Sci., study senior author and member of the LJI Center for Infectious Disease and Vaccine Research. "We can presume that T cells would still be available as a line of defense against viral infection."

The researchers emphasize that the study only addresses how the body's T cells respond to Variants of Concern (VOCs). The researchers emphasize that several of these variants, are linked to lower levels of virus-fighting antibodies.

The current study includes data on four of the most prevalent VOCs. Ongoing studies have been expanded to a larger panel of variants, including the Delta (B.1.617.2) variant, which became prevalent after this study had been initiated. The team has also established relationships with more than 20 different laboratories around the world to help monitor T cell reactivity to VOCs.

"These variants are still a concern, but our study shows that even if there is a decrease in antibodies, as other studies have shown, the T cells remain largely unaffected," says LJI Instructor Alba Grifoni, Ph.D. "The vaccines still work."

The Johnson & Johnson/Janssen COVID-19 vaccine was not part of this study because it was not available at the time the study was launched.

LJI findings guide COVID-19 vaccine efforts

This study was previously published online as a pre-print in March 2021. The findings were then highlighted by National Institutes of Allergy and Infectious Diseases Director Anthony Fauci, M.D., in a March 31 White House press briefing.

"We're learning more and more that these CD4+ and CD8+ T cells are very important in that they cross-react against certain viral variants," Fauci said.

In the time since the paper was first published, the researchers nearly tripled their patient cohort and performed an additional method of stringent statistical analysis. "We've also added an unexposed donor cohort," says study first author Alison Tarke, a Ph.D. student of the University of Genoa, guested in the Sette Lab at LJI.

For the new study, the researchers analyzed T cells from three different groups: people who had recovered from COVID-19, people who had received either the Moderna or Pfizer-BioNTech vaccines, and people never exposed to SARS-CoV-2 (from samples taken before the pandemic).

Both the recovered subjects and the vaccinated subjects were likely to have T cells that recognized the "ancestral lineage" of SARS-CoV-2. This was the original strain that emerged at the beginning of the pandemic; however, the virus has mutated since December 2019, and several variants have been identified as VOCs.

The question was whether people with T cells trained to recognize the ancestral strain would also recognize the new variants. The researchers tested T cell responses from the donor groups against four prominent VOCs: Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1) and Epsilon (B.1.427/B.1.429).

The researchers found that both vaccinated individuals and the recovered patients had cross-reactive T cells that could target these variants. That is good news for anyone who has received one of the two mRNA vaccines and for anyone who has recovered from any variant of the virus.

"With this study, the underlying message is optimistic," adds Tarke. "At least, as far as the T cell response goes, your immune system is still able to recognize these new variants and your T cells will be able to respond."

Similar results reporting largely unaffected T cell reactivity has now been presented through independent studies published in Nature and Science Immunology.

Study co-author and LJI Professor Shane Crotty, Ph.D., says this research highlights the importance of enlisting T cells in fighting SARS-CoV-2.

"COVID vaccines do a fantastic job of making antibodies that stop SARS-CoV-2 infections, but some of the vaccines do less well at stopping infections from variants," Crotty says. "You can think of T cells as a backup system: if the virus gets past the antibodies--if you have vaccine T cells the T cells can probably still stop the variant coronavirus infection before you get pneumonia."

Researchers are now looking for ways to take advantage of how flexible the T cells response appears to be. With T cells already working hard to recognize SARS-CoV-2 variants, Grifoni says future "booster" shots could increase immunity by prompting the body to produce more antibodies against the variants and/or by adding additional parts of the virus recognized by T cells.

"T cell epitopes are well conserved among SARS-CoV-2 variants, so incorporating T cell targets into future COVID vaccines could be a clever way to make sure future variants can't escape the vaccines," adds Crotty.

There is also the possibility that current SARS-CoV-2 research may one day lead to a universal, "pan-coronavirus" vaccine. This kind of vaccine would train the body to recognize the structural details, such as elements of the spike protein, that all coronaviruses have in common.

"This research shows that a pan-coronavirus vaccine is feasible," says Grifoni.

The group is now studying a much larger group of 12 different Variants of Concern (VOCs) and Variants of Interest (VOIs), including the Delta variant (B.1.617.2), Eta (B.1.525), Iota (B.1.526), Kappa (B.1.617.1), Lambda (C37) and the variants B.1.526.1, B.1.617.3, R1 and B.1.1.519.

Sette says he'd also like to study T cells from people who have been infected with the variants and see how those T cells react to the ancestral strain of the virus.

Minority-ethnic medical students must have more role-models in senior leadership positions if they are to engage with academia. This is one of the conclusions drawn by a group of medical students writing in the Journal of the Royal Society of Medicine about the drivers and barriers to engaging with academia.

Barriers currently hampering the chances of minority-ethnic medical students accessing formal pathways into academia, they write, include differential attainment and unconscious bias, difficulties forming meaningful mentor-mentee relationships, as well as the lack of role models from minority-ethnic backgrounds.

Drawing on their own experiences, the medical students write that while progress has been made to increase the number of academics from minority ethnic backgrounds, the same progress has not been made celebrating them as people or their contributions to science, especially given the inspirational impact individuals such as Mary Seacole or Charles Richard Drew have had on future generations of students.

Co-author Carlos Curtis-Lopez, of the University of Manchester medical school, said: "Nationally, major research funders and policymakers could start by making a real statement of intent addressing this problem. They should also ensure a proportion of those in senior leadership positions reflect the entire population that they serve and that there is diverse representation across committees, selection and award panels."

He added: "By having medical students from minority-ethnic backgrounds see something of themselves among those in senior leadership roles, it could be enough of a nudge to push them into having a conversation with academics in their institutions about pursuing a career in academia."

Senior author Dr Rakesh Patel, Clinical Associate Professor in Medical Education at the University of Nottingham, said: "Given diversity of thinking and representation are associated with greater scientific impact and growth, not having minority-ethnic students consider academia is a lost opportunity for all."

In an article appearing in Nature Biomedical Engineering, a team of scientists from the UCLA David Geffen School of Medicine and UCLA School of Engineering report real-world results on SwabSeq, a high-throughput testing platform that uses sequencing to test thousands of samples at a time to detect COVID-19. They were able to perform more than 80,000 tests in less than two months, with the test showing extremely high sensitivity and specificity.

SwabSeq uses sample-specific molecular barcodes to simultaneously analyze thousands of samples for the presence or absence of SARS-CoV-2, the virus that causes COVID-19. SwabSeq was granted FDA Emergency Use Authorization in October and is currently deployed at UCLA in a high-complexity CLIA laboratory, which has performed over 150,000 tests since December 2020. SwabSeq is a flexible protocol and can rapidly scale up testing for novel pathogens, including COVID-19 and future emerging viruses.

"We have optimized SwabSeq to prioritize scale and low cost, key factors that are missing from current COVID-19 diagnostics," the authors write.

"These results demonstrate the potential of SwabSeq to be used for SARS-CoV-2 testing on an unprecedented scale," said Dr. Valerie Arboleda, Assistant Professor and lead scientist on the project. "SwabSeq offers a potential solution to the need for population-wide testing to stem the pandemic." In the months since, the team has continued to use the test, and as of this date has performed more than 150,000 tests.

The groundbreaking technology was developed in a collaboration between scientists at the Department of Computational Medicine affiliated with both the David Geffen School of Medicine and the Samueli School of Engineering at UCLA, the Department of Human Genetics, the Department of Pathology and Laboratory Medicine, and Octant, a start-up company founded and incubated at UCLA. SwabSeq is a modification of Octant's technology that is being applied toward drug discovery and has been made available broadly to fight the pandemic. UCLA scientists have been leading a broader coalition of academic and industrial labs around the country and the world to develop the technology to scale up COVID-19 testing.