Earth

Cantona: Long series of droughts doomed Mexican city 1,000 years ago

rchaeologists continue to debate the reasons for the collapse of many Central American cities and states, from Teotihuacan in Mexico to the Yucatan Maya, and climate change is considered one of the major causes.

A University of California, Berkeley, study sheds new light on this question, providing evidence that a prolonged period of below-average rainfall was partly responsible for the abandonment of one such city, Cantona, between A.D. 900 and A.D. 1050.

Corn co-products from wet milling fine for pig diets

Many co-products from the corn processing industry may be used in diets fed to pigs. Much attention over the last 10 years has been on co-products produced from the biofuels industry, including distillers dried grains and high-protein distillers grains. However, the wet milling industry also produces many different co-products that may be used in pig diets.

Holes in valence bands of nanodiamonds discovered

But how are the electronic properties of nanodiamonds deposited on a solid-state substrate different from those displayed by nanodiamonds in aqueous solutions?

Dr. Tristan Petit working in the HZB team headed by Prof. Emad F. Aziz has now investigated this with the help of absorption and emission spectroscopy at BESSY II. Their results, just published in Nanoscale, demonstrate that nanodiamonds display valence holes in aqueous solutions, which are not observed when characterized as a thin film.

Beer compound could help fend off Alzheimer's and Parkinson's diseases

The health-promoting perks of wine have attracted the spotlight recently, leaving beer in the shadows. But scientists are discovering new ways in which the latter could be a more healthful beverage than once thought. They're now reporting in ACS' Journal of Agricultural and Food Chemistry that a compound from hops could protect brain cells from damage -- and potentially slow the development of disorders such as Alzheimer's and Parkinson's diseases.

Blind water beetles 'challenge the traditional Darwinian view of evolution'

University of Adelaide researchers have made a surprising discovery in the aquifers beneath the Western Australian desert, which they say challenges the traditional Darwinian view of evolution.

A team, lead by Dr Simon Tierney, discovered that a species of blind predatory water beetles - living underground for millions of years - express vision genes (opsin) which are usually only found in species with eyes. The research was published in the reputable journal, Royal Society Open Science.

Into the dark: Two new Palythoa encrusting anemones found in coral reef caves

Researchers have found two new species of encrusting anemones, or colonial zoantharians, in unexpected locations.

The two species belong to the genus Palythoa, which is commonly found on shallow coral reefs in subtropical and tropical waters worldwide. Surprisingly, the two new species were found living in cracks and caves in the reefs, and do not have zooxanthellae, unlike almost other known Palythoa species. Zooxanthellae are symbiotic, photosynthetic, single-celled algae that can provide host species with energy from the sun.

Researchers use sound to slow down, speed up, and block light

How do you make an optical fiber transmit light only one way?

Natural plant compounds that work against insects identified

Each year millions of deaths result from diseases transmitted by insects. Insects are also responsible for major economic losses, worth billions of dollars annually, by damaging crops and stored agricultural products.

Many currently available insecticides present environmental and health risks. Further, insects develop resistance to existing insecticides, complicating pest-control strategies. The need to develop novel effective insecticides is therefore urgent.

Infant failure to thrive linked to lysosome dysfunction

Neonatal intestinal disorders that prevent infants from getting the nutrients they need may be caused by defects in the lysosomal system that occur before weaning, according to a new study. Lysosomes are cellular recycling centers responsible for breaking down all kinds of biological material.

The study in PLOS Genetics links lysosomal dysfunction with intestinal disorders for the first time, pointing to a previously unknown target for research and future therapies to help infants unable to absorb milk nutrients and gain weight, a diagnosis called failure to thrive.

Easter Island population collapse still a mystery

Long before the Europeans arrived on Easter Island in 1722, the native Polynesian culture known as Rapa Nui showed signs of demographic decline. However, the catalyst has long been debated in the scientific community. Was environmental degradation the cause, or could a political revolution or an epidemic of disease be to blame?

Man trumps dog: EFSA and the US FDA validated on BPA decisions

Coating the mouth with BPA-containing food, like soup, does not lead to higher than expected levels of BPA in blood, a new study in Toxicology and Applied Pharmacology shows. The study authors conclude that oral exposure does not create a risk for high exposures.

BPA, also known as bisphenol A, is used to make some plastics and to seal canned food containers against bacterial contamination. Food, which picks up trace amounts of BPA from packaging, is the major source of human exposure.

Early Mexicans affected by climate change in 500 AD

Scientists have reconstructed the past climate for the region around Cantona, a large fortified city in highland Mexico, and found the population drastically declined in the past, at least in part because of climate change.

Lawrence Livermore researcher Susan Zimmerman and colleagues analyzed pollen, stable isotopes and elemental concentrations, which serve as proxies of past climatic and environmental conditions from lake sediments in the region and found evidence of a regional drought between 500 and 1150 A.D., about the same time Cantona was abandoned.

Things smell good for a nutritional reason

Antioxidants are natural food ingredients that protect cells from harmful influences. Their main task is to neutralize so-called "free radicals" which are produced in the process of oxidation and which are responsible for cell degeneration.

Staircase fractures in microbialites and travertines

In the new GSA BULLETIN, Matteo Maggi and colleagues from Italy and Brazil present a new model of the development of fractures showing a stairway trajectory, commonly occurring in finely laminated rock, such microbialites and travertines.

These fractures strongly enhance permeability by connecting several highly porous zones enveloped in tight impermeable levels. Understanding and predicting this fracture pattern geometry, distribution, and interconnection is valuable not only for locating water supplies, but also for oil, gas, and geothermal exploration.

Climate models disagree on why temperature 'wiggles' occur

A new Duke University-led study finds that most climate models likely underestimate the degree of decade-to-decade variability occurring in mean surface temperatures as Earth's atmosphere warms. The models also provide inconsistent explanations of why this variability occurs in the first place.

These discrepancies may undermine the models' reliability for projecting the short-term pace as well as the extent of future warming, the study's authors warn. As such, we shouldn't over-interpret recent temperature trends.