Παρασκευή, 23 Μαΐου 2014

ScienceDaily: Top Environment News

ScienceDaily: Top Environment News

Male, female sex cell determination requires lifelong maintenance, protection

Posted: 22 May 2014 02:57 PM PDT

The way in which the sex of an organism is determined may require lifelong maintenance, finds new research. Sex-specific transcription factors perform lifelong work to maintain sexual determination and protect against reprogramming of cells from one sex to the other. Using a mouse model, researchers found the sex of gonadal cells -- those found in the ovaries or testes -- require maintenance throughout life. This research also showed loss of a single transcription factor can result in the transformation of male cells into female cells.

Promising discovery in fight against antibiotic-resistant bacteria

Posted: 22 May 2014 02:57 PM PDT

A small molecule that prevents bacteria from forming into biofilms, a frequent cause of infections, has been discovered by researchers. The anti-biofilm peptide works on a range of bacteria including many that cannot be treated by antibiotics. "Currently there is a severe problem with antibiotic-resistant organisms," says the lead author of the study. "Our entire arsenal of antibiotics is gradually losing effectiveness."

Biofilm defense: Mechanisms and actions of a new class of broad-spectrum antimicrobials

Posted: 22 May 2014 02:57 PM PDT

Last month WHO issued a report that warned of an increase of antimicrobial-resistance and the renewed threat of bacterial infections world-wide and called for a concerted effort to develop new and better antimicrobial drugs. A new study reveals how a new type of antimicrobial substance interferes with biofilms formed by several dangerous bacteria.

Delegating dirty work is key to evolution: Working cells allow organisms to evolve

Posted: 22 May 2014 11:14 AM PDT

We have hundreds of types of cells in our bodies -- everything from red blood cells to hair follicles to neurons. But why can't most of them create offspring for us? New research suggests that separating germ cells -- sperm and eggs -- from somatic cells -- all other cells -- preserves the genetic building blocks while allowing organisms to flourish in a somewhat hazardous environment.

Deep Earth recycling of the oceanic floor: New insight into the temperature of deep Earth

Posted: 22 May 2014 11:14 AM PDT

Scientists have recreated the extreme conditions 600 to 2900 km below the Earth's surface to investigate the melting of basalt in the oceanic tectonic plates. They exposed microscopic pieces of rock to these extreme pressures and temperatures while simultaneously studying their structure. The results show basalt produced on the ocean floor has a melting temperature lower than the peridotite which forms the Earth's mantle.

Earth's lower mantle may be significantly different than previously thought

Posted: 22 May 2014 11:14 AM PDT

Breaking research news reveals that the composition of the Earth's lower mantle may be significantly different than previously thought. The lower mantle comprises 55 percent of the planet by volume and extends from 670 and 2900 kilometers in depth, as defined by the so-called transition zone (top) and the core-mantle boundary (below). Pressures in the lower mantle start at 237,000 times atmospheric pressure (24 gigapascals) and reach 1.3 million times atmospheric pressure (136 gigapascals) at the core-mantle boundary.

Fruit flies show mark of intelligence in thinking before they act, study suggests

Posted: 22 May 2014 11:14 AM PDT

Fruit flies 'think' before they act, a study suggests. Neuroscientists showed that fruit flies take longer to make more difficult decisions. In experiments asking fruit flies to distinguish between ever closer concentrations of an odor, the researchers found that the flies don't act instinctively or impulsively. Instead they appear to accumulate information before committing to a choice.

A glimpse into nature's looking glass -- to find the genetic code is reassigned: Stop codon varies widely

Posted: 22 May 2014 11:14 AM PDT

It has long been assumed that there is only one 'canonical' genetic code, so each word means the same thing to every organism. Now, this paradigm has been challenged by the discovery of large numbers of exceptions from the canonical genetic code.

Ancient DNA ends Australia's claim to kiwi origins

Posted: 22 May 2014 11:13 AM PDT

Australia can no longer lay claim to the origins of the iconic New Zealand kiwi following new research showing the kiwi's closest relative is not the emu as was previously thought. Instead, the diminutive kiwi is most closely related to the extinct Madagascan elephant bird -- a 2-3 meter tall, 275 kg giant. And surprisingly, the study concluded, both of these flightless birds once flew.

Collecting biological specimens essential to science and conservation, experts argue

Posted: 22 May 2014 11:13 AM PDT

Collecting plant and animal specimens is essential for scientific studies and conservation and does not, as some critics of the practice have suggested, play a significant role in species extinctions. Those are the conclusions of more than 100 biologists and biodiversity researchers.

New details on microtubules and how the anti-cancer drug Taxol works

Posted: 22 May 2014 10:34 AM PDT

Images of microtubule assembly and disassembly have been produced by researchers at the unprecedented resolution of 5 angstroms, providing new insight into the success of the anti-cancer drug Taxol and pointing the way to possible improvements. "This is the first experimental demonstration of the link between nucleotide state and tubulin conformation within the microtubules and, by extension, the relationship between tubulin conformation and the transition from assembled to disassembled microtubule structure," says a biophysicist on the study.

Near-normal or below-normal 2014 Atlantic hurricane season predicted

Posted: 22 May 2014 10:28 AM PDT

In its 2014 Atlantic hurricane season outlook issued today NOAA's Climate Prediction Center is forecasting a near-normal or below-normal season. The main driver of this year's outlook is the anticipated development of El Niño this summer. El Niño causes stronger wind shear, which reduces the number and intensity of tropical storms and hurricanes. El Niño can also strengthen the trade winds and increase the atmospheric stability across the tropical Atlantic, making it more difficult for cloud systems coming off of Africa to intensify into tropical storms.

Near-normal or above-normal Eastern Pacific hurricane season predicted

Posted: 22 May 2014 10:25 AM PDT

NOAA's Climate Prediction Center has announced that a near-normal or above-normal hurricane season is likely for the Eastern Pacific this year. The outlook calls for a 50 percent chance of an above-normal season, a 40 percent chance of a near-normal season, and a 10 percent chance of a below normal season.

Near-normal or above-normal Central Pacific hurricane season predicted

Posted: 22 May 2014 10:21 AM PDT

NOAA's Central Pacific Hurricane Center announced that climate conditions point to a near-normal or above-normal season in the Central Pacific Basin this year. For 2014, the outlook calls for a 40 percent chance of a near-normal season, a 40 percent chance of an above-normal season, and a 20 percent chance of a below-normal season.

Blocking pain receptors extends lifespan, boosts metabolism in mice

Posted: 22 May 2014 09:35 AM PDT

Chronic pain is known to shorten lifespan, and pain tends to increase with age. But is there a relationship between pain and longevity? Researchers have found that mice lacking the capsaicin pain receptor live around 14 percent longer than other mice, and they retain a more youthful metabolism as well. Receptor blockers could not only relieve pain, but increase lifespan, improve metabolic health and help diabetics and the obese.

Computer models helping unravel the science of life? How cells of the fruit fly react to changes in the environment

Posted: 22 May 2014 09:35 AM PDT

Scientists have developed a sophisticated computer modelling simulation to explore how cells of the fruit fly react to changes in the environment. The model shows how cells of the fruit fly communicate with each other during its development.

Safe alternatives to BPA: New technology may help identify

Posted: 22 May 2014 09:34 AM PDT

Numerous studies have linked exposure to bisphenol A (BPA) in plastic, receipt paper, toys, and other products with various health problems from poor growth to cancer, and the FDA has been supporting efforts to find and use alternatives. But are these alternatives safer? Researchers have developed new tests that can classify such compounds' activity with great detail and speed. The advance could offer a fast and cost-effective way to identify safe replacements for BPA.

Wondering about state of the environment? Just eavesdrop on bees

Posted: 22 May 2014 09:34 AM PDT

Want a simple way to monitor wide swaths of the landscape without breaking a sweat? Listen in on the 'conversations' honeybees have with each other, researchers suggest. The scientists' analyses of honeybee waggle dances suggest that costly measures to set aside agricultural lands and let the wildflowers grow can be very beneficial to bees.

HIV-positive children more likely to develop drug resistance

Posted: 22 May 2014 09:33 AM PDT

74 percent of HIV-positive children in a study developed resistance to at least one form of drug treatment. The researchers followed almost 450 children enrolled in the Pediatric HIV/AIDS Cohort Study, one of the largest studies of HIV-positive children in the United States. "The problem with drug resistance is that once you develop it, it never goes away," said the principal investigator. "Some patients with very resistant virus have no effective treatment options. Resistant virus is the major reason for death among youth with perinatal HIV."

Pathology of Sanfilippo A syndrome: Research provides more insight

Posted: 22 May 2014 07:51 AM PDT

Sanfilippo A syndrome is a rare genetic lysosomal storage disease inherited from the parents of the patient. Lysosomes are the body's vehicle for breaking down many of its by-products such as proteins, nucleic acids, carbohydrates, lipids and cellular debris. New research advances the knowledge of the structural features of sulfamidase in the context of this illness, and will greatly facilitate the discovery of suitable compounds and drugs to assist in managing the disease and its debilitating effects.

Fossil avatars are transforming palaeontology

Posted: 22 May 2014 07:51 AM PDT

New techniques for visualizing fossils are transforming our understanding of evolutionary history. Palaeontology has traditionally proceeded slowly, with individual scientists labouring for years or even decades over the interpretation of single fossils. The introduction of X-ray tomography has revolutionized the way that fossils are studied, allowing them to be virtually extracted from the rock in a fraction of the time necessary to prepare specimens by hand and without the risk of damaging the fossil.

European farmers: Importance of adapting to climate change

Posted: 22 May 2014 07:49 AM PDT

Farmers in Europe will see crop yields affected as global temperatures rise, but that adaptation can help slow the decline for some crops. Research reveals that farmers in Europe will see crop yields affected as global temperatures rise, but that adaptation can help slow the decline for some crops. For corn, the anticipated loss is roughly 10 percent, the research shows. Farmers of these crops have already seen yield growth slow down since 1980 as temperatures have risen, though other policy and economic factors have also played a role.

There is still hope for the climate: Regional cures for planetary fever

Posted: 22 May 2014 07:48 AM PDT

There is still hope for the climate, even if a world-wide climate accord proves to be unattainable. A new report shows that regional measures can hold the global rise in temperature within the two-degree limit.

Devastating human impact on the Amazon rainforest revealed

Posted: 22 May 2014 07:48 AM PDT

The human impact on the Amazon rainforest has been grossly underestimated according to an international team of researchers. They found that selective logging and surface wildfires can result in an annual loss of 54 billion tons of carbon from the Brazilian Amazon, increasing greenhouse gas emissions. This is equivalent to 40% of the yearly carbon loss from deforestation -- when entire forests are chopped down.

Marriage of convenience with a fungus: Equal for all plants, or just some?

Posted: 22 May 2014 07:48 AM PDT

Thanks to a fungus, the medicinal plant ribwort plantain gains a higher concentration of the defensive compound catalpol. The increase in catalpol gives the plant better protection against pests. In the study, the research team worked with arbuscular mycorrhizal fungi. These are known to colonize the roots of land plants. The plants benefit from this because the fungus provides them with nutrients and minerals. However, are the impacts of this marriage of convenience with the fungus on plant chemistry equal for all plants? That is what the researchers wanted to find out.

Inexpensive food a key factor in rising obesity

Posted: 22 May 2014 04:47 AM PDT

An important factor fueling the obesity epidemic has been identified by a new review: Americans now have the cheapest food available in history. Today, two in three Americans are overweight or obese, with rates climbing steadily over the past several decades. Many factors have been suggested as causes: snack food, automobiles, television, fast food, computer use, vending machines, suburban housing developments, and portion size. But after examining available evidence, the authors say widespread availability of inexpensive food appears to have the strongest link to obesity.

Could cannabis active substance curb seizures? Experts weed through evidence

Posted: 22 May 2014 04:47 AM PDT

The therapeutic potential of medical marijuana and pure cannabidiol (CBD), an active substance in the cannabis plant, for neurologic conditions is highly debated. A series of articles examine the potential use of medical marijuana and CBD in treating severe forms of epilepsy such as Dravet syndrome.

Top ten new species for 2014

Posted: 22 May 2014 04:33 AM PDT

An international committee selected the top 10 from among the approximately 18,000 new species named during the previous year. The list includes a quartet of tiny newcomers to science: a miniscule skeleton shrimp from Santa Catalina Island in California, a single-celled protist that does a credible imitation of a sponge, a clean room microbe that could be a hazard during space travel and a teensy fringed fairyfly named Tinkerbell.

More male bugs in a warmer world? Temperature influences gender of offspring in bugs

Posted: 22 May 2014 04:33 AM PDT

Whether an insect will have a male or female offspring depends on the weather, according to a new study. As in bees, wasps, and ants, the gender determination of Trichogramma parasitoids is called "haplodiploid," that is, fertilized eggs produce female offspring, while unfertilized eggs produce male offspring. The study found that when it was hot, females deliberately produced more males than at medium temperature -- at 34°C, the number of males produced increased by 80%.

Dryland ecosystems emerge as driver in global carbon cycle

Posted: 21 May 2014 03:00 PM PDT

Dryland ecosystems, which include deserts to dry-shrublands, play a more important role in the global carbon cycle than previously thought. In fact, they have emerged as one of its drivers. Surprised by the discovery, researchers urged global ecologists to include the emerging role of dryland ecosystems in their research.

Ape ancestors' teeth provide glimpse into their diets and environments: Helped apes move to Eurasia, may have led to extinction

Posted: 21 May 2014 03:00 PM PDT

Newly analyzed tooth samples from the great apes of the Miocene indicate that the same dietary specialization that allowed the apes to move from Africa to Eurasia may have led to their extinction. Apes expanded into Eurasia from Africa during the Miocene (14 to 7 million years ago) and evolved to survive in new habitat. Their diet closely relates to the environment in which they live and each type of diet wears the teeth differently.

Evaluating 'acquired immunity' may improve estimates of infectious disease risk

Posted: 21 May 2014 10:31 AM PDT

A new health study that accounts for "acquired immunity" when evaluating the risk of microbial illness from food or environmental exposures suggests that some current approaches may significantly overestimate their role in causing such illnesses. Immune status is a major factor in susceptibility to foodborne and environmental infectious diseases. By considering both the impact of acquired immunity to a pathogen and the amount of a pathogen to which people are exposed, researchers have developed a novel approach for more accurately assessing the potential health risks of infectious diseases.

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