Senin, 28 Juli 2014

ScienceDaily: Top Science News

ScienceDaily: Top Science News

Climate change and air pollution will combine to curb food supplies

Posted: 27 Jul 2014 01:57 PM PDT

Many studies have shown the potential for global climate change to cut food supplies. But these studies have, for the most part, ignored the interactions between increasing temperature and air pollution -- specifically ozone pollution, which is known to damage crops. A new study shows that these interactions can be quite significant, suggesting that policymakers need to take both warming and air pollution into account in addressing food security.

Trees save lives, reduce respiratory problems

Posted: 25 Jul 2014 01:35 PM PDT

In the first broad-scale estimate of air pollution removal by trees nationwide, scientists have calculated that trees are saving more than 850 human lives a year and preventing 670,000 incidences of acute respiratory symptoms. The study considered four pollutants for which the U.S. EPA has established air quality standards: nitrogen dioxide, ozone, sulfur dioxide, and particulate matter less than 2.5 microns (PM2.5) in aerodynamic diameter.

Climate Change Increases Risk of Crop Slowdown in Next 20 Years

Posted: 25 Jul 2014 11:44 AM PDT

The world faces a small but substantially increased risk over the next two decades of a major slowdown in the growth of global corn and wheat yields because of climate change, according to new research. Such a slowdown would occur as global demand for crops rapidly increases.

Invertebrate numbers nearly halve as human population doubles

Posted: 24 Jul 2014 11:16 AM PDT

Invertebrate numbers have decreased by 45 percent on average over a 35 year period in which the human population doubled, reports a study on the impact of humans on declining animal numbers. This decline matters because of the enormous benefits invertebrates such as insects, spiders, crustaceans, slugs and worms bring to our day-to-day lives, including pollination and pest control for crops, decomposition for nutrient cycling, water filtration and human health.

Geography of global electronic waste ('e-waste') burden

Posted: 23 Jul 2014 08:11 AM PDT

As local and national governments struggle to deal with ever-growing piles of electronic waste, scientists are now refining the picture of just how much there is and where it really ends up. Their study found that nearly a quarter of e-waste that developed countries discard floods into just seven developing countries -- with major potential health risks for the people who live there.

Intestinal parasites are 'old friends,' researchers argue

Posted: 23 Jul 2014 08:11 AM PDT

Intestinal parasites such as tapeworms, hookworms and a protist called Blastocystis can be beneficial to human health, according to a new paper that argues we should rethink our views of organisms that live off the human body. To prove the point, a co-author even ingested three developmental stages of a large species of tapeworm called Diphyllobothrium latum. After more than a year with the tapeworms, which might have grown to be as long as four metres each by now, he says he feels fine.
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Sabtu, 26 Juli 2014

ScienceDaily: Top Science News

ScienceDaily: Top Science News

Intensity of hurricanes: New study helps improve predictions of storm intensity

Posted: 25 Jul 2014 08:08 AM PDT

While predicting the path of hurricanes has gotten better, little has been done to improve predicting a storm's intensity. That is, until now. "The air-water interface -- whether it had significant waves or significant spray -- is a big factor in storm intensity," said one expert involved in a new study. "Hurricanes gain heat energy through the interface and they lose mechanical energy at the interface."

Bacteria manipulate salt to build shelters to hibernate

Posted: 25 Jul 2014 05:03 AM PDT

For the first time, researchers have detected an unknown interaction between microorganisms and salt. When Escherichia coli cells are introduced into a droplet of salt water that is left to dry, bacteria manipulate the sodium chloride crystallization to create biomineralogical biosaline 3-D morphologically complex formations, where they hibernate. Afterwards, simply by rehydrating the material, bacteria are revived. The discovery was made by chance with a home microscope.

Steam energy from the sun: New spongelike structure converts solar energy into steam

Posted: 24 Jul 2014 06:39 PM PDT

A new material structure generates steam by soaking up the sun. The structure -- a layer of graphite flakes and an underlying carbon foam -- is a porous, insulating material structure that floats on water. When sunlight hits the structure's surface, it creates a hotspot in the graphite, drawing water up through the material's pores, where it evaporates as steam. The brighter the light, the more steam is generated.

Saharan dust is key to formation of Bahamas' Great Bank, study finds

Posted: 24 Jul 2014 03:29 PM PDT

Saharan dust played a major role in the formation of the Bahamas islands, a new study suggests. Researchers showed that iron-rich Saharan dust provides the nutrients necessary for specialized bacteria to produce the island chain's carbonate-based foundation. Persistent winds across Africa's 3.5-million square mile Sahara Desert lifts mineral-rich sand into the atmosphere where it travels the nearly 5,000-mile northwest journey towards the U.S. and Caribbean.

Brain's dynamic duel underlies win-win choices

Posted: 24 Jul 2014 02:20 PM PDT

People choosing between two or more equally positive outcomes experience paradoxical feelings of pleasure and anxiety, feelings associated with activity in different regions of the brain, according to research. In the study, participants made choices between paired products with different or similar values. Choosing between two items of high value evoked the most positive feelings and the greatest anxiety.

'Naïve' pluripotent human embryonic stem cells created

Posted: 24 Jul 2014 09:36 AM PDT

Embryonic stem cell (ESC) research has been hampered by the inability to transfer research and tools from mouse ESC studies to their human counterparts, in part because human ESCs are "primed" and slightly less plastic than the mouse cells. Now researchers have discovered how to manipulate and maintain human ESCs into a "naïve" or base pluripotent state similar to that of mouse ESCs without the use of any reprogramming factors.

Maltreatment affects the way children's genes are activated

Posted: 24 Jul 2014 06:42 AM PDT

In a new study, researchers found that maltreatment affects the way children's genes are activated, which has implications for their long-term development and health. The researchers examined DNA methylation, a biomechanical mechanism that helps cells control which genes are turned on or off, in the blood of 56 children ages 11 to 14. Disruptions in this system affect emotional behavior, stress levels, and the immune system. These findings echo those of earlier studies of rodents.

Bacteria swim with whole body, not just propellers

Posted: 21 Jul 2014 12:19 PM PDT

Many bacteria swim using flagella, corkscrew-like appendages that push or pull bacterial cells like tiny propellers. It's long been assumed that the flagella do all the work during swimming, while the rest of the cell body is just along for the ride. But new research shows that a helical movement of the cell body generates thrust and helps the organism to swim.

Rearchers eliminate HIV virus from cultured human cells for first time

Posted: 21 Jul 2014 12:19 PM PDT

The HIV-1 virus has proved to be tenacious, inserting its genome permanently into its victims' DNA, forcing patients to take a lifelong drug regimen to control the virus and prevent a fresh attack. Now, a team of researchers has designed a way to snip out the integrated HIV-1 genes for good.
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