Earth | Page 730 | Science Codex

Maize roots have evolved to be more nitrogen efficient

Selective breeding of maize over the last century to create hybrids with desirable shoot characteristics and increased yield may have contributed indirectly to the evolution of root systems that are more efficient in acquiring nutrients, such as nitrogen, from the soil, according to researchers.

Their results suggest that future breeding efforts that directly select for positive root traits could lead to yield gains needed to help feed a growing world population, while reducing pollution from excess nitrogen and reducing farmers' fertilizer costs.

Wildfire greenhouse gases are under-counted in California climate targets

Wildfires are contributing more than expected to California's greenhouse gas emissions, according to a new study in Forest Ecology and Management. The results could have implications for California's efforts to meet goals mandated by its own Global Warming Solutions Act, or AB 32, to reduce greenhouse gas emissions to 1990 levels by the year 2020. The bill, which passed in 2006, assumed no net emissions for wildland ecosystems by 2020.

Heavy snoring, sleep apnea may signal earlier memory and thinking decline

Heavy snoring and sleep apnea may be linked to memory and thinking decline at an earlier age, according to a new study published in Neurology. The research also suggests that treating the disorders with a breathing machine may delay the decline.

"Abnormal breathing patterns during sleep such as heavy snoring and sleep apnea are common in the elderly, affecting about 52 percent of men and 26 percent of women," said study author Ricardo Osorio, MD, with the NYU Langone Medical Center in New York.

BPA linked to disrupted sexual function in turtles

Bisphenol A (BPA) is a chemical that is used in a variety of consumer products, such as food storage products and resins that line plastic food and beverage containers. Often, aquatic environments such as rivers and streams become reservoirs for BPA, and fish and turtle habitats are affected. Now, a collaboration of researchers from the University of Missouri, Westminster College, the U.S. Geological Survey and the Saint Louis Zoo have determined that BPA--which mimics estrogen--can alter a turtle's reproductive system and disrupts sexual differentiation.

Bird populations still reduced in Fukushima

Since a few months after the March 11, 2011, earthquake, tsunami and subsequent nuclear release at Japan's Fukushima-Daiichi nuclear power plant, Mousseau and several co-workers have undertaken a series of bird censuses in contaminated areas.

Many populations were found to have diminished in number as a result of the accident, with several species suffering dramatic declines. One hard-hit species was the barn swallow, Hirundo rustica, which suffered large population losses in a dose-dependent manner according to individually measured levels of radiation exposure.

Wind bursts may be why El Niño was El Ninot

In today's media-driven climate environment, where storms are SuperStorms and Snowpocalypses, the hype cycle had issued high expectations for the El Niño - and then little happened. On March 5, 2015, the National Weather Service finally declared a "weak" event arriving several months later than expected, formally dashing predictions that we would see a major event on par with the monster El Niño of 1997/98 that would bring much-needed rain to California and other western states.

Frogs use different strategies to avoid air and ground predators

Frogs may flee from a ground predator and move towards an aerial predator, undercutting the flight path, according to a study using model predators by Matthew Bulbert from Macquarie University, Australia and colleagues.

Are populations aging more slowly than we think?

Faster increases in life expectancy do not necessarily produce faster population aging, according to new research. This counterintuitive finding was the result of applying new measures of aging developed at International Institute for Applied Systems Analysis (IIASA) to future population projections for Europe up to the year 2050.

Iceberg armadas not the cause of North Atlantic cooling

Previous studies have suggested that pulses of icebergs may have caused cycles of abrupt climate change during the last glacial period by introducing fresh water to the surface of the ocean and changing ocean currents, which are known to play a dominant role in the climate of many of Earth's regions.

However, new findings by scientists at Cardiff University present a contradictory narrative and suggest that icebergs generally arrived too late to trigger marked cooling across the North Atlantic.

Discovery of new plant switch could boost crops, biofuel production

A switch that regulates plant photosynthesis - the process that lets plants store solar energy - can be optimized to boost foodd and biofuel crop production.

Photosynthesis stores energy in two forms that are used to power plants' metabolism. The amount of energy flowing into each of these must be perfectly balanced to match the needs of plants' metabolism or the plant will self-destruct.

E-cigarette use is not risk-free

E-cigarettes are not without health risks for people who vape or for bystanders. This is one of the conclusions from a new risk assessment report from the Norwegian Institute of Public Health (NIPH).

The report has only considered e-cigarettes with nicotine since there has been very little research about e-cigarettes without nicotine.

In summary

The evolutionary history of citrus

Citrus fruits -- delectable oranges, lemons, limes, kumquats and grapefruits -- are among the most important commercially cultivated fruit trees in the world, yet little is known of the origin of the citrus species and the history of its domestication.

Now, Joaquin Dopazo et al, in a new publication in the journal Molecular Biology and Evolution, have performed the largest and most detailed genomic analysis on 30 species of Citrus, representing 34 citrus genotypes, and used chloroplast genomic data to reconstruct its evolutionary history.

Typhoon Haiyan's storm surge may contaminate Philippines aquifer for years

In 2013, Typhoon Haiyan devastated the Philippines, killing more than 6,000 people and destroying nearly $3 billion worth of property. While the country is still recovering from the storm, researchers with The University of Texas at Austin have found that an aquifer on the island of Samar inundated with salt water by the storm surge could remain undrinkable for up to 10 years. But a second aquifer on the island that was also inundated has recovered much more quickly.

Nature helps agriculture too

A team of international scientists has shown that assigning a dollar value to the benefits nature provides agriculture improves the bottom line for farmers while protecting the environment. The study confirms that organic farming systems do a better job of capitalizing on nature's services.

Infectious ants become antisocial

Looking after yourself, and trying not to infect others, is a good strategy to prevent disease from spreading - not only if you are a considerate co-worker, but also if you are an ant, meerkat or other social animal, as revealed by an epidemiological model developed by the groups of Professor Fabian Theis from the Helmholtz Center Munich and Professor Sylvia Cremer from the Institute of Science and Technology (IST) Austria.