Τρίτη, 1 Ιουλίου 2014

ScienceDaily: Top News

ScienceDaily: Top News

It's a girl! Gene silencing technology alters sex of prawns

Posted: 30 Jun 2014 04:34 PM PDT

Scientists have developed a novel method for generating single-sex populations of prawns. This could be used to boost the productivity of aquaculture farms and even as a biocontrol measure against invasive species and pests.

DNA analysis reveals that queen bumblebees disperse far from their birthplace before setting up home

Posted: 30 Jun 2014 04:33 PM PDT

Researchers are closer to understanding patterns of family relatedness and genetic diversity in bumblebees. The findings could help farmers, land managers and policy makers develop more effective conservation schemes for these essential pollinators.

Using geometry, researchers coax human embryonic stem cells to organize themselves

Posted: 30 Jun 2014 01:45 PM PDT

By confining colonies of human embryonic stem cells to tiny circular patterns on glass plates, researchers have for the first time coaxed them into organizing themselves just as they would under natural conditions.

Ancient Arctic sharks tolerated brackish water 50 million years ago

Posted: 30 Jun 2014 01:43 PM PDT

Sharks were a tolerant bunch some 50 million years ago, cruising an Arctic Ocean that contained about the same percentage of freshwater as Louisiana's Lake Ponchatrain does today, says a new study. The study indicates the Eocene Arctic sand tiger shark, a member of the lamniform group of sharks that includes today's great white, thresher and mako sharks, was thriving in the brackish water of the western Arctic Ocean back then. In contrast, modern sand tiger sharks living today in the Atlantic Ocean are very intolerant of low salinity, requiring three times the saltiness of the Eocene sharks in order to survive.

All the world's oceans have plastic debris on their surface

Posted: 30 Jun 2014 01:42 PM PDT

The Malaspina Expedition, led by the Spanish National Research Council, has demonstrated that there are five large accumulations of plastic debris in the open ocean that match with the five major twists of oceanic surface water circulation. In addition to the known accumulation of plastic waste in the North Pacific, there are similar accumulations in the central North Atlantic, the South Pacific, the South Atlantic and the Indian Ocean.

Ancient baby boom holds a lesson in over-population

Posted: 30 Jun 2014 01:41 PM PDT

Researchers have sketched out one of the greatest baby booms in North American history, a centuries-long 'growth blip' among southwestern Native Americans between 500 to 1300 A.D. It was a time when the early features of civilization -- including farming and food storage -- had matured to where birth rates likely 'exceeded the highest in the world today,' the researchers write. A crash followed, offering a warning sign to the modern world about the dangers of overpopulation.

Body odor reveals malarial infection

Posted: 30 Jun 2014 01:40 PM PDT

An infection with malaria pathogens changes the scent of infected mice, making those infected more attractive to mosquitoes, according to a new study. Researchers show that whether mosquitoes find the right victim to bite is not left to chance by the pathogen. Instead, the plasmodium parasite appears to manipulate its host by changing the characteristics of the infected individual's body odour, which makes the carrier more attractive to hungry mosquitoes.

New method to grow zebrafish embryonic stem cells

Posted: 30 Jun 2014 01:40 PM PDT

Zebrafish, a model organism that plays an important role in biological research and the discovery and development of new drugs and cell-based therapies, can form embryonic stem cells (ESCs). For the first time, researchers report the ability to maintain zebrafish-derived ESCs for more than two years without the need to grow them on a feeder cell layer.

Study of animal urination could lead to better-engineered products

Posted: 30 Jun 2014 01:40 PM PDT

A new study investigated how quickly 32 animals urinate. It turns out that it's all about the same. Even though an elephant's bladder is 3,600 times larger than a cat's (18 liters vs. 5 milliliters), both animals relieve themselves in about 20 seconds.

Evolution of life’s operating system revealed in detail

Posted: 30 Jun 2014 01:40 PM PDT

The evolution of the ribosome, a large molecular structure found in the cells of all species, has been revealed in unprecedented detail in a new study.

Surgical treatment for metastatic melanoma of the liver increases overall survival

Posted: 30 Jun 2014 11:14 AM PDT

Surgical resection markedly improves survival among metastatic melanoma patients whose disease is isolated to a few areas in the liver, according to a new study. The bottom line, according the researchers, is that surgeons should discuss surgical resection for the treatment of melanoma liver metastases with their patients if their disease is limited to a few areas in the liver, their overall health status is good, and the disease is indolent or the patients are responding to systemic therapy.

In human evolution, changes in skin's barrier set northern Europeans apart

Posted: 30 Jun 2014 11:08 AM PDT

The popular idea that northern Europeans developed light skin to absorb more UV light so they could make more vitamin D -- vital for healthy bones and immune function -- is questioned by researchers in a new study. Ramping up the skin's capacity to capture UV light to make vitamin D is indeed important, however, researchers concluded in their study that changes in the skin's function as a barrier to the elements made a greater contribution than alterations in skin pigment in the ability of northern Europeans to make vitamin D.

Reigning in chaos in particle colliders yields big results

Posted: 30 Jun 2014 11:08 AM PDT

Physicists have published details on an important method of detecting and correcting unwanted chaotic behavior in particle colliders. The method is helping accelerator physicists design high-performing, cost-efficient accelerators in an era of constrained science budgets.

Potentially habitable Earth-like planet discovered; May have similar temperatures to our planet

Posted: 30 Jun 2014 10:34 AM PDT

A potentially habitable Earth-like planet that is only 16 light years away has been discovered. The "super-Earth" planet, GJ 832 c, takes 16 days to orbit its red-dwarf star, GJ 832, and has a mass at least five times that of Earth. It receives about the same average stellar energy as Earth does and may have similar temperatures to our planet. These characteristics put it among the top three most Earth-like planets.

19th century math tactic gets a makeover -- and yields answers up to 200 times faster

Posted: 30 Jun 2014 09:49 AM PDT

A relic from long before the age of supercomputers, the 169-year-old math strategy called the Jacobi iterative method is widely dismissed today as too slow to be useful. But thanks to a curious, numbers-savvy engineering student and his professor, it may soon get a new lease on life.

Are you seen as a jerk at work? Many people are oblivious to how they come across to counterparts and colleagues

Posted: 30 Jun 2014 09:48 AM PDT

New research shows that many people seen by others as under-assertive or over-assertive think they're appropriately assertive. The study also reveals that people seen as getting assertiveness right often mistakenly think they've gotten it wrong.

Combatting drug resistance for melanoma patients

Posted: 30 Jun 2014 09:44 AM PDT

A new way to identify possible therapeutic targets for patients with drug resistant melanoma has been developed by researchers. It involves using liquid chromatography-multiple reaction monitoring mass spectrometry to measure biomarkers or molecules in blood and tissue that indicates cancer is present. These measurements can help researchers determine if a patient is responding to treatment.

New study from population and development review finds flaws in mortality projections

Posted: 30 Jun 2014 09:44 AM PDT

Demographers have found that mortality projections from most low-mortality countries are more pessimistic than they should be. Existing projections fail to recognize that fewer people smoke today than used to. As a result, there will be a future decline in smoking-related mortality. This suggests that with more people living longer, pension and health care costs in coming decades will likely be higher than previously estimated.

Potential drug target for PTSD prevention

Posted: 30 Jun 2014 09:44 AM PDT

A drug that appears to make memories of fearsome events less durable in mice has been discovered by researchers. The finding may accelerate the development of treatments for preventing PTSD. The drug, called osanetant, targets a distinct group of brain cells in a region of the brain that controls the formation and consolidation of fear memories.

Key component of cell division comes to light

Posted: 30 Jun 2014 09:44 AM PDT

The in vivo visualization and monitoring of the starting points of microtubules -- filaments responsible for organizing the mitotic spindle -- provides novel insight into the dynamic architecture of this structure. The findings will also contribute to understanding how the mitotic spindle is perturbed by drugs that target microtubules and that are used in chemotherapy.

Forelimb bone data predicts predator style

Posted: 30 Jun 2014 09:44 AM PDT

In their quest to understand what kind of hunter the extinct marsupial Thylacine was, two paleobiologists built a dataset of forelimb bone measurements that predict the predation style of a wide variety of carnivorous mammals.

Bacterial colonies evolve amazing diversity

Posted: 30 Jun 2014 09:44 AM PDT

Like human societies -- think New York City -- bacterial colonies have immense diversity among their inhabitants, often generated in the absence of specific selection pressures, according to a new article.

Energy storage technology: More pores for more power

Posted: 30 Jun 2014 09:43 AM PDT

When can we expect to drive the length of Germany in an electric car without having to top up the battery? Chemists have now synthesized a new material that could show the way forward to state-of-the-art lithium-sulfur batteries.

Smashing new look at nanoribbons: Researchers unzip nanotubes by shooting them at 15,000 mph

Posted: 30 Jun 2014 08:41 AM PDT

Scientists have discovered they can unzip nanotubes into graphene nanoribbons without chemicals by firing them at a target at 15,000 miles per hour. Materials scientists discovered that nanotubes that hit a target end first turn into mostly ragged clumps of atoms. But nanotubes that happen to broadside the target unzip into handy ribbons that can be used in composite materials for strength and applications that take advantage of their desirable electrical properties.

Interlayer distance in graphite oxide gradually changes when water is added

Posted: 30 Jun 2014 08:41 AM PDT

Physicists have solved a mystery that has puzzled scientists for half a century. They show with the help of powerful microscopes that the distance between graphite oxide layers gradually increases when water molecules are added. That is because the surface of graphite oxide is not flat, but varies in thickness with 'hills' and 'valleys' of nanosize.

Cocaine addiction: Phase-specific biology, treatment?

Posted: 30 Jun 2014 07:31 AM PDT

Current pharmacotherapies for addiction follow the dictum 'one size fits all'. Medications are prescribed in the same way for all patients, regardless of whether they have just started experimenting with a drug or have an established drug habit. Even more troubling, there are no FDA-approved pharmacotherapies for some addictions, such as compulsive cocaine use.

A first: Scientists show bacteria can evolve biological timer to survive antibiotics

Posted: 30 Jun 2014 07:31 AM PDT

When exposed to repeated cycles of antibiotics, within days bacteria can evolve a new adaptation, by remaining dormant for the treatment period to survive antibiotic stress. The results show for the first time that bacteria can develop a biological timer to survive antibiotic exposure. With this new understanding, scientists could develop new approaches for slowing the evolution of antibiotic resistance.

Mysterious features on Saturn's Titan reveal the moon's seasonal changes

Posted: 30 Jun 2014 06:48 AM PDT

At first glance, Titan has little in common with Earth. The largest moon of Saturn, temperatures on Titan's surface dip nearly 300 F below zero, its seas slosh with liquid methane, and its sky is a murky shade of creamsicle. And yet, fresh analysis of mysterious features spotted on the moon indicates that it experiences one of the same global processes that is important here on Earth. Bright spots in a large lake on Titan suggest that Saturn's largest moon supports processes similar to Earth's water cycle.

Missing protein explains link between obesity, diabetes

Posted: 30 Jun 2014 06:48 AM PDT

Obese individuals lack a protein that is essential for regulating blood glucose levels, causing them to face higher risks of developing diabetes, researchers have discovered. The protein is one of the first molecular links found between obesity to diabetes and is potentially a target for treatment or prevention of diabetes in obese individuals.

Father's ethnic background influences birthweight, study finds

Posted: 30 Jun 2014 06:48 AM PDT

A father's ethnic background can influence a child's birthweight, a new study has found. Current birthweight curves -- graphs used to plot how one baby's weight compares to others of the same age -- assume that the parents are of Western European descent. That means many babies of an East Asian or South Asian mother may be classified as underweight, when in fact they are "normal" for their ethnic groups. The new study shows the same is true when the father is of Asian descent.

No link between fertility drugs and breast, ovarian, uterine cancers, study finds

Posted: 30 Jun 2014 06:47 AM PDT

There is 'little evidence' that the use of conventional fertility hormones used for ovarian stimulation in the treatment of infertility increases the long-term risk of breast and gynecological cancers, according to the results of a substantial 30-year follow-up study. The study was a retrospective investigation involving 12,193 women treated for infertility between 1965 and 1988 at five US sites. A total of 9,892 women were successfully followed for cancer outcomes.

Children born to women after fertility treatment at greater risk of psychiatric disorders

Posted: 30 Jun 2014 06:47 AM PDT

Children born to women with fertility problems have a higher risk of psychiatric disorders than naturally conceived children, Danish research suggests. The increase in risk was described as 'modest' by researchers, but was found to persist throughout childhood and into young adulthood. Research suggests that 1.9% of all diagnosed psychiatric disorders in Denmark are associated with the mother's infertility.

Whaling logbooks could hold key to retreating Arctic ice fronts

Posted: 30 Jun 2014 06:46 AM PDT

Ice fronts from the early 19th century were far more advanced around the Arctic than they are today, researchers analysing whalers' log books from this time have discovered.

Quantum dots created with single-atom precision

Posted: 30 Jun 2014 06:45 AM PDT

Physicists have used a scanning tunneling microscope to create quantum dots with identical, deterministic sizes. The perfect reproducibility of these dots opens the door to quantum dot architectures completely free of uncontrolled variations, an important goal for technologies from nanophotonics to quantum information processing as well as for fundamental studies.

Early traumas and young people's reactions to terror

Posted: 30 Jun 2014 06:45 AM PDT

Adolescents can have post-traumatic stress reactions even when not directly affected by terrorist attacks. They are at increased risk if they have experienced violence or sexual abuse in early life. Those who have experienced sexual abuse numerous times have a doubled risk of post-traumatic stress reactions to a terrorist incident, new research finds.

Almonds reduce the risk of heart disease, research shows

Posted: 30 Jun 2014 06:45 AM PDT

Eating almonds can reduce the risk of heart disease by keeping blood vessels healthy, research has shown. Research found that they significantly increase the amount of antioxidants in the blood stream, reduce blood pressure and improve blood flow. These findings add weight to the theory that Mediterranean diets with lots of nuts have big health benefits.

More carbohydrates make trees more resistant to drought

Posted: 30 Jun 2014 06:36 AM PDT

How well tropical trees weather periods of drought depends on the carbohydrates stored, as revealed by a novel experiment conducted by an international team of researchers. The findings are extremely important for assessing the resistance of tropical forests to climate change and reforestation.

Climate change in the North Sea: Long-term studies reveal drastic changes in the marine fauna

Posted: 30 Jun 2014 06:36 AM PDT

Long-term studies have revealed obvious changes in the North Sea's biota. Studies during the past twenty years indicate that southern species increasingly expand northward. The Atlantic cod is drawn to cooler regions, while crustaceans from southern areas spread ever farther into the North Sea. The effects of the climate change can be clearly felt on the German sea coasts, as well.

Algae as chemical raw materials

Posted: 30 Jun 2014 06:36 AM PDT

Chemists and biologists have succeeded in transforming algae oil into high-quality chemical raw materials via so-called isomerizing alkoxycarbonylation. This provides the foundation for the use of algae as a basic chemical component for a broad spectrum of materials and products, beyond the use of algae as a substitute for crude oil.

Learn Dutch in your sleep: Listening to lessons while sleeping reinforces memory

Posted: 30 Jun 2014 06:36 AM PDT

When you have learned words in another language, it may be worth listening to them again in your sleep. A study has now shown that this method reinforces memory. "Our method is easy to use in daily life and can be adopted by anyone," says the study director.

Insights from nature for more efficient water splitting

Posted: 30 Jun 2014 06:36 AM PDT

Water splitting is one of the critical reactions that sustain life on Earth, and could be a key to the creation of future fuels. It is a key in the process of photosynthesis, through which plants produce glucose and oxygen from water and carbon dioxide, using sunlight as energy. However, there are still significant mysteries about the process.

One third of knee replacements classified as inappropriate

Posted: 30 Jun 2014 06:36 AM PDT

More than one third of total knee replacements in the U.S. were classified as "inappropriate" using a patient classification system developed and validated in Spain, a new article reports. The study highlights the need for consensus on patient selection criteria among U.S. medical professionals treating those with the potential need of knee replacement surgery.

Silver in the washing machine: Nano-coatings release almost no nano-particles, experts say

Posted: 30 Jun 2014 06:33 AM PDT

The antibacterial properties of silver-coated textiles are popular in the fields of sport and medicine. Scientists have now investigated how different silver coatings behave in the washing machine, and they have discovered something important: textiles with nano-coatings release fewer nano-particles into the washing water than those with normal coatings.

It may take guts to cure diabetes

Posted: 30 Jun 2014 06:33 AM PDT

By switching off a single gene, scientists have converted human gastrointestinal cells into insulin-producing cells, demonstrating in principle that a drug could retrain cells inside a person's GI tract to produce insulin. The finding raises the possibility that cells lost in type 1 diabetes may be more easily replaced through the reeducation of existing cells than through the transplantation of new cells created from embryonic or adult stem cells.

Fat damages the lungs of heavy drinkers

Posted: 30 Jun 2014 06:33 AM PDT

The so called fatty liver disease that long time drinkers develop may extend to the lung in a newly discovered side effect of drinking in rats that researchers are calling fatty lung disease. Heavy drinking damages the body in many ways. In addition to liver failure, alcoholics are at a much greater risk of developing pneumonia and life threatening acute respiratory distress syndrome (ARDS), for which there is no treatment.

Common herbal supplement can cause dangerous interactions with prescription drugs

Posted: 30 Jun 2014 06:33 AM PDT

St. John's wort, the leading complementary and alternative treatment for depression in the United States, can be dangerous when taken with many commonly prescribed drugs, according to a study. The researchers reported that the herbal supplement can reduce the concentration of numerous drugs in the body, including oral contraceptive, blood thinners, cancer chemotherapy and blood pressure medications, resulting in impaired effectiveness and treatment failure.

Gene variants found that increase pain sensation after common childhood surgery

Posted: 30 Jun 2014 06:33 AM PDT

The first genome-wide analysis of postsurgical pain in children has identified gene variants that affect a child's need for pain-control drugs. The findings may advance the process of calibrating pain-medication doses to a child's genetic makeup. "Although this research is only a first step for our team, it provides tremendous new insight into the biological mechanisms and brings us a little closer to personalizing medicine for pain control," said a co-author.

Successful test of saucer-shaped vehicle for future Mars missions

Posted: 30 Jun 2014 05:12 AM PDT

NASA has successfully conducted the first of three planned tests for the Low-Density Supersonic Decelerator (LDSD) project, developed to evaluate new landing technologies for future Mars missions. While this initial test was designed to determine the flying ability of the vehicle, it also deployed two new landing technologies as a bonus. Those landing technologies will be officially tested in the next two flights, involving clones of the saucer-shaped vehicle.

Counterintuitive phenomenon: Coexistence of superconductivity with dissipation

Posted: 29 Jun 2014 11:21 AM PDT

A novel way to fabricate superconducting nanocircuitry has been developed. However, the newly designed extremely small zinc nanowires did some unexpected -- and sort of funky -- things.

Improved method for isotope enrichment could secure a vital global commodity

Posted: 29 Jun 2014 11:20 AM PDT

Researchers have devised a new method for enriching a group of the world's most expensive chemical commodities, stable isotopes, which are vital to medical imaging and nuclear power. For many isotopes, the new method is cheaper than existing methods. For others, it is more environmentally friendly.

Single-pixel 'multiplex' captures elusive terahertz images

Posted: 29 Jun 2014 11:20 AM PDT

In an effort that advances attempts to generate images using terahertz light waves, researchers report that they've developing a single-pixel 'multiplex' device that uses boutique metamaterials to capture images in the terahertz realm, which scientists say could play a crucial role in future medical and security imaging initiatives.

High carbon dioxide levels cause warming in tropics

Posted: 29 Jun 2014 11:20 AM PDT

Higher concentrations of carbon dioxide in the atmosphere cause warming not only at high latitudes but also across tropical regions, according to new research. "These results confirm what climate models have long predicted -- that although greenhouse gases cause greater warming at the poles they also cause warming in the tropics. Such findings indicate that few places on Earth will be immune to global warming and that the tropics will likely experience associated climate impacts, such as increased tropical storm intensity," the project leader said.

Watching individual neurons respond to magnetic therapy

Posted: 29 Jun 2014 11:20 AM PDT

A method to record an individual neuron's response to transcranial magnetic stimulation therapy has been developed by researchers. The advance will help researchers understand the underlying physiological effects of TMS -- a procedure used to treat psychiatric disorders -- and optimize its use as a therapeutic treatment.

Single gene separates aggressive, non-aggressive lymphatic system cancer

Posted: 29 Jun 2014 11:20 AM PDT

For a rare form of cancer called thymoma, researchers have discovered a single gene defining the difference between a fast-growing tumor requiring aggressive treatment and a slow-growing tumor that doesn't require extensive therapy. Most of the diagnosed patients have surgery, but, depending on the presumed aggressiveness of the cancer, some patients will have radiation and/or chemotherapy in addition or instead of surgery.

Reconstructing the life history of a single cell: Cell's unique mutations used to trace history back to its origins in the embryo

Posted: 29 Jun 2014 11:17 AM PDT

Researchers have developed new methods to trace the life history of individual cells back to their origins in the fertilised egg. By looking at the copy of the human genome present in healthy cells, they were able to build a picture of each cell's development from the early embryo on its journey to become part of an adult organ. 

Marine bacteria are natural source of chemical fire retardants

Posted: 29 Jun 2014 11:17 AM PDT

Researchers have discovered a widely distributed group of marine bacteria that produce compounds nearly identical to toxic human-made fire retardants.

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