In mammals, an individual's sex is determined by the chromosomes it inherits from its parents. Two X chromosomes lead to a female, whereas one X and one Y lead to a male. Y chromosomes are only passed from fathers to sons, so each Y chromosome represents the male genealogy of the animal in question. In contrast, mitochondria are passed on by mothers to all their offspring. This means that an analysis of the genetic material or DNA of mitochondria can give information on the female ancestry. For the modern horse, it is well known that mitochondrial DNA is extremely ...

PHILADELPHIA, April 4, 2013 – – A new report on teen driver safety released today by The Children's Hospital of Philadelphia (CHOP) and State Farm® shows encouraging trends among teen passengers. In 2011 more than half of teen passengers (54 percent) reported "always" buckling up. From 2008 to 2011, risky behaviors of teen passengers (ages 15 to 19 years) declined: the number of teen passengers killed in crashes not wearing seat belts decreased 23 percent; the number of teen passengers driven by a peer who had been drinking declined 14 percent; and 30 percent fewer teen ...

Global population data spanning the years from 1900 to 2010 have enabled a research team from the Autonomous University of Madrid to predict that the number of people on Earth will stabilise around the middle of the century. The results, obtained with a model used by physicists, coincide with the UN's downward forecasts. According to United Nations' estimates, the world population in 2100 will be within a range between 15.8 billion people according to the highest estimates –high fertility variant– and 6.2 billion according to the lowest –low fertility variant–, a figure ...

Springtime spells tick-time. Lyme borreliosis is the most common tick-borne disease in Switzerland: around 10,000 people a year become infected with the pathogen. The actual hosts for Borrelia, however, are wild mice. Like in humans, the pathogen is also transmitted by ticks in mice. Interestingly, not all mice are equally susceptible to the bacterium and individual animals are immune to the pathogen. Scientists from the universities of Zurich and Lund headed by evolutionary biologist Barbara Tschirren reveal that the difference in vulnerability among the animals is genetic ...

Researchers at the University of Leeds may have solved a key puzzle about how objects from space could have kindled life on Earth. While it is generally accepted that some important ingredients for life came from meteorites bombarding the early Earth, scientists have not been able to explain how that inanimate rock transformed into the building blocks of life. This new study shows how a chemical, similar to one now found in all living cells and vital for generating the energy that makes something alive, could have been created when meteorites containing phosphorus minerals ...

Professor of neurology, physician, and author Oliver Sacks M.D. has outlined case studies of hallucinations of musical notation, and commented on the neural basis of such hallucinations, in a new paper for the neurology journal Brain. In this paper, Dr Sacks is building on work done by Dominic ffytche et al in 2000 [i], which delineates more than a dozen types of hallucinations, particularly in relation to people with Charles Bonnet syndrome (a condition that causes patients with visual loss to have complex visual hallucinations). While ffytche believes that hallucinations ...

Los Angeles, CA (April 04, 2013). Graduates are taking up jobs that don't fully use their skills and as a result are causing high turnover for employers, claims new research published today in the journal Human Relations, published by SAGE. The findings raise questions about today's high throughput in university education. Policy makers in many developed and developing countries envisioned high-value economies supported in part by a highly-skilled and well-paid workforce. As a result, many nations have increased higher education (HE) access, assuming that employers will ...

ANN ARBOR, Mich. — The costs of caring for people with dementia in the U.S. are comparable to – if not greater than – those for heart disease and cancer, according to new estimates by researchers at the University of Michigan Health System and nonprofit RAND Corporation. Annual healthcare costs tied to dementia, including both formal and unpaid care, reach $159-$215 billion – rivaling the most costly major diseases – according to the findings that appear in The New England Journal of Medicine. "Our findings show why dementia is sometimes described as a 'slow-motion ...

A standard camera takes flat, 2-D pictures. To get 3-D information, such as the distance to a far-away object, scientists can bounce a laser beam off the object and measure how long it takes the light to travel back to a detector. The technique, called time-of-flight (ToF), is already used in machine vision, navigation systems for autonomous vehicles, and other applications, but many current ToF systems have a relatively short range and struggle to image objects that do not reflect laser light well. A team of Scotland-based physicists has recently tackled these limitations ...

The number of online education offerings has exploded in recent years, but such "virtual" classes have also been plagued by one critical question – can classes offered online cut through the maze of distractions – email, the Internet, TV and more – that face students as they sit in front of a computer? The answer, Harvard researchers say, is to test students early and often. By interspersing online lectures with short tests, student mind wandering decreased by 50 percent, note-taking tripled and overall retention of the material improved, said Daniel Schacter, the ...

In a geological moment about 66 million years ago, something killed off almost all the dinosaurs and some 70 percent of all other species living on Earth. Only those dinosaurs related to birds appear to have survived. Most scientists agree that the culprit in this extinction was extraterrestrial, and the prevailing opinion has been that the party crasher was an asteroid. Not so, say two Dartmouth researchers. Professors Jason Moore and Mukul Sharma of the Department of Earth Sciences favor another explanation, asserting that a high-velocity comet led to the demise of ...

SOUTH BEND, IND. – Scientists from the University of Notre Dame, The Nature Conservancy, and Central Michigan University presented their findings of Asian carp DNA throughout the Great Lakes in a study published in the Canadian Journal of Fisheries and Aquatic Sciences. "The good news is that we have found no evidence that Asian carp are widespread in the Great Lakes basin, despite extensive surveys in Southern Lake Michigan and parts of lakes Erie and St Clair," said Dr. Christopher Jerde, the paper's lead author and a scientist at the University of Notre Dame, "Looking ...

The genus Megachile is a cosmopolitan group of solitary bees, often called leafcutter bees. This is one of the largest genera of bees, with well over 1,500 species in over 50 subgenera. A new species, Megachile chomskyi, has been found only in Texas, US. What is specific and interesting about this bee is the fact that it is among those insects which exhibit a narrow, specialized preference for pollen sources. Presumably, the irreplaceable host of M. chomskyi are the beautiful flowers of the widespread Onagraceae, or the so-called Evening-Primrose Family. The study has been ...

Owing to the huge array of applications, catalysis has long been dubbed as one of the most significant areas of process and synthetic chemistry. In fact, the vast majority of all chemical industrial products – be it in the field of pharmaceutical, agricultural or polymer chemistry – involve catalysts at some stage of the manufacturing process. Catalytic processes are generally conducted in homogeneous phase using anhydrous organic solvents (e.g. halogenated solvents, toluene, etc.) which are very toxic and hard to eliminate. The development of environmentally friendly ...

The supernova, designated SN UDS10Wil [1], belongs to a special class of exploding stars known as Type Ia supernovae. These bright beacons are prized by astronomers because they can be used as a yardstick for measuring cosmic distances, thereby yielding clues to the nature of dark energy, the mysterious force accelerating the rate of expansion of the Universe. "This new distance record holder opens a window into the early Universe, offering important new insights into how these supernovae form," said astronomer David O. Jones of The Johns Hopkins University in Baltimore, ...

New Rochelle, NY, April 4, 2013—Pet therapy can help patients cope with the pain, stress, and emotional effects of a serious illness, but access to a companion animal is not always possible. Robotic animals may offer the same benefits, as explored in a fascinating study presented in Cyberpsychology, Behavior, and Social Networking, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free online on the Cyberpsychology, Behavior, and Social Networking website. Sandra Okita, PhD, Columbia University (New York, NY) evaluated the effectiveness ...

CHAPEL HILL, N.C – Viruses have historically been classified into one of two types – those with an outer lipid-containing envelope and those without an envelope. For the first time, researchers at the University of North Carolina have discovered that hepatitis A virus, a common cause of enterically-transmitted hepatitis, takes on characteristics of both virus types depending on whether it is in a host or in the environment. "The whole universe of virology is divided into two types of viruses – viruses that are enveloped and viruses that are not enveloped. If you look ...

The observation that males appear to be superior to females in some fields of academic study has prompted a wealth of research hoping to shed light on whether this is attributable to nature or nurture. Although there is no difference in general intelligence between the sexes, studies over the past 35 years have consistently found that overall men do much better in tests of spatial ability than women. This difference may have something to do with why there are still fewer women in tertiary education studying science, technology, engineering and math – all subjects where ...

A new study which was performed jointly at Umeå University and the University of Washington in Seattle, USA, discovered that bacteria can degrade the cell membrane of bacterial competitors with enzymes that do not harm their own membrane. This exciting finding opens the way for the development of new antibacterial drugs to fight bacteria using their own weapons. (NATURE, 2013). During the infection of a host organism, pathogenic bacteria can excrete toxins that cause damage to host cells and tissue. Interestingly, bacteria also use similar mechanisms in competition with ...

Results from an anonymous survey of U.S. transplant providers report that incarceration, marijuana use, and psychiatric diagnoses, particularly suicide attempts, may lower patients' eligibility for liver transplantation. The study published in the April issue of Liver Transplantation, a journal of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society, also found that most providers would not offer transplants to patients with advanced age, those severely obese, or with lifetime imprisonment. "For patients with end-stage ...

Analysis of a bronze battering ram from a 2000 year-old warship sheds light on how such an object would have been made in ancient times. Known as the Belgammel Ram, the 20kg artefact was discovered by a group of British divers off the coast of Libya near Tobruk in 1964. The ram is from a small Greek or Roman warship – a "tesseraria". These ships were equipped with massive bronze rams on the bow at the waterline and were used for ramming the side timbers of enemy ships. At 65cm long, the Belgammel Ram is smaller in size and would have been sited on the upper level on the ...

Scientists from the University of Notre Dame, The Nature Conservancy, and Central Michigan University have presented their findings of Asian carp DNA throughout the Great Lakes in a study published in the Canadian Journal of Fisheries and Aquatic Sciences. "The good news is that we have found no evidence that Asian carp are widespread in the Great Lakes basin, despite extensive surveys in Southern Lake Michigan and parts of lakes Erie and St Clair," Christopher Jerde, the paper's lead author and a scientist at the University of Notre Dame, said. "Looking at the overall ...

Amsterdam, NL, April 4, 2013 – In a study designed to differentiate why some stroke patients recover from aphasia and others do not, investigators have found that a compensatory reorganization of language function to right hemispheric brain regions bodes poorly for language recovery. Patients who recovered from aphasia showed a return to normal left-hemispheric language activation patterns. These results, which may open up new rehabilitation strategies, are available in the current issue of Restorative Neurology and Neuroscience. "Overall, approximately 30% of patients ...

Children's sense of having and owning a body differs from that of adults, indicating that our sense of physical self develops over time, according to a new study published in Psychological Science, a journal of the Association for Psychological Science. Many of our senses — vision, touch, and body orientation — come together to inform our perception of having and owning a body. Psychological scientist Dorothy Cowie of Goldsmiths, University of London and colleagues hypothesized that there might be age differences in how these processes come together. To test this hypothesis, ...

NASA's Hubble Space Telescope has found the farthest supernova so far of the type used to measure cosmic distances. Supernova UDS10Wil, nicknamed SN Wilson after American President Woodrow Wilson, exploded more than 10 billion years ago. SN Wilson belongs to a special class called Type Ia supernovae. These bright beacons are prized by astronomers because they provide a consistent level of brightness that can be used to measure the expansion of space. They also yield clues to the nature of dark energy, the mysterious force accelerating the rate of expansion. "This new ...