Cats killing billions of animals in the US

Cats are one of the top threats to US wildlife, killing billions of animals each year, a study suggests.

The authors estimate they are responsible for the deaths of between 1.4 and 3.7 billion birds and 6.9-20.7 billion mammals annually.

Writing in Nature Communications, the scientists said stray and feral cats were the worst offenders.

However, they added that pet cats also played a role and that owners should do more to reduce their impact.

The authors concluded that more animals are dying at the claws of cats in the United States than in road accidents, collisions with buildings or poisonings.

The domestic cat's killer instinct of has been well documented on many islands around the world.

Felines accompanying their human companions have gone on to decimate local wildlife, and they have been blamed for the global extinction of 33 species.

But their impact on mainland areas has been harder to chart.

To find out more, researchers from the Smithsonian Conservation Biology Institute (SCBI) and the US Fish and Wildlife Service carried out a review of studies that had previously looked at the predatory prowess of cats.

Their analysis revealed that the cat killings were much higher than previous studies had suggested: they found that they had killed more than four times as many birds as has been previously estimated.

Birds native to the US, such as the American Robin, were most at risk, and mice, shrews, voles, squirrels and rabbits were the mammals most likely to be killed.

Dr Pete Marra from the SCBI said: "Our study suggests that they are the top threat to US wildlife."

The team said that "un-owned" cats, which they classified as strays, feral cats and farm cats, were killing about three times as many animals as pet cats, but that their owners could do more to limit the impact.

Dr Marra said: "We hope that the large amount of wildlife mortality indicated by our research convinces some cat owners to keep their cats indoors and that it alerts policymakers, wildlife managers and scientists to the large magnitude of wildlife mortality caused by cat predation."

A spokeswoman for the UK's animal welfare charity the RSPCA said that a properly fitted collar and bell could reduce a cat's success when hunting by at least a third.

R.S

Brazil to survey Amazon rainforest

The Brazilian government has announced that it plans to undertake the huge task of recording an inventory of the trees in the Amazon rainforest.

The Forestry Ministry said the census would take four years to complete, and would provide detailed data on tree species, soils and biodiversity in the world's largest rainforest.

 The last exhaustive survey was carried out more than 30 years ago.

In that time the rainforest has become increasingly threatened by logging.

The Brazilian government made a commitment in 2009 to reduce deforestation in the Amazon by 80% by the year 2020,according to BBC.

According to the government, in 2012 the destruction of the Amazon rainforest reached its lowest level since monitoring began more than two decades ago.

But ministers said they would be able to act more effectively if they had more accurate data.

"We are going to come to know the rainforest from within," Forestry Minister Antonio Carlos Hummel said announcing the inventory.

Environment Minister Izabella Teixeira said it would help the government to formulate environmental policies.

"In international debates about climate change, for example, we will know how much forest we have and what state it is in (...), we'll discover species, and gain knowledge about species becoming extinct, as well as information about the distribution of the forest and its potential economic use", Ms Teixeira said.

Brazil's national development bank said it would contribute $33m to the project.

The last detailed survey of the Brazilian Amazon was carried out in the 1970s, and its results published in 1983.

Forestry Minister Hummel said partial results would be published yearly, as it progressed.

M.Wassouf

 

New clock revolves around an atom's mass

It’s part clock, part scale: A newly developed atomic clock measures time based on the mass of a single atom. The research, published online January 10 in Science, is controversial but could provide scientists with more precise methods of measuring both time and mass.

“This is the first clock based on a single particle,” says Holger Müller, a physicist at the University of California, Berkeley. “Its ticking rate is determined only by the particle’s mass.”

The idea for the clock stemmed from the quantum principle that particles also behave as waves, and vice versa. In particular, Müller and his colleagues wanted to determine how frequently the wave form of a single atom oscillates, a quantity that in quantum mechanics is inherently linked to the atom’s mass. Then the researchers could use those oscillations like swings of a pendulum to create a clock,according to Science News Magazine.

The snag in Müller’s plan was that it’s impossible to directly measure the oscillation frequency of waves of matter. The frequency of these waves is about 1025 hertz, 10 orders of magnitude higher than that of visible light waves. So Müller and his colleagues came up with an apparatus that creates two sets of waves — one based on a cesium atom at rest and another on the atom in motion. The researchers measured the frequency difference between the waves and then used that number, a manageable 100,000 hertz or so, to calculate the much larger oscillation frequency of cesium at rest.

With this approach, Müller was able to use the wave frequency of the cesium atom to create a clock that would gain or lose a second after eight years. That’s better than a wristwatch but about a hundred millionth as precise as today’s best atomic clocks, which count the frequency of light emissions from an atom as its electrons release small bursts of energy.

Physicists not involved with Müller’s research are impressed with his clever technique but are skeptical about its potential for precise timekeeping. “I think the paper is slightly oversold,” says Vladan Vuletić, a quantum physicist at MIT.

Other researchers have a more conceptual objection: Because there is nothing at this frequency actually oscillating within the atom, they say it is not a clock at all. “It may be a clock numerically, but it’s not a physical clock,” says Christian Bordé, a physicist at the Paris Observatory. Müller counters that the clock’s simplicity is its greatest trait: He is measuring an intrinsic quantum property of an atom, one that depends only on the atom’s mass.

In fact, this relationship between frequency and mass means Müller’s technique may prove most useful as a scale for measuring mass. Scientists define the kilogram, the base unit of mass, with a lump of metal stored in a French vault — a lump that is likely gaining heft from contamination (SN: 11/20/10, p. 12). The international General Conference on Weights and Measures, led by Bordé, wants to replace this artifact with a kilogram standard based on fundamental physical constants.

Müller says he can do just that by measuring the frequency of matter waves to accurately determine an atom’s mass. Once he finds the mass of one atom, he says, it is straightforward to relate it to the masses of other atoms. He will have a lot of convincing to do, but Müller plans to let the scientific process play out to test his ideas. “This is a concept that physicists never thought about,” he says. “This frequency wasn’t measurable until now."

M.W

Gamma-Ray Burst Blasted Earth in 8th Century: Study

A mystery wave of cosmic radiation that smashed into Earth in the eighth century may have come from two black holes that collided, a study published on Monday says, according to AFP.

 Clues for the strange event were unearthed last year by Japanese astrophysicist Fusa Miyake, who discovered a surge in carbon-14 -- an isotope that derives from high-energy radiation -- in the rings of ancient cedar trees.

 Dating of the trees showed that the burst struck the Earth in either 774 or 775 AD.

 But what was the nature of the radiation, and what caused it?

 Space scientists lined up the usual suspects only to let them go. There was no evidence that an exploding star, also called a supernova, occurred at that time, they found.

 The Anglo-Saxon Chronicle, a record in Old English, makes a dramatic reference to the appearance of a "red crucifix" seen in the skies after sunset. But that happened in 776 AD, which was too late to tally with the event marked by the tree rings.

 Also ruled out was a tantrum by the Sun, which can throw out sizzling cosmic rays or gouts of energy called solar flares.

 Writing in Monthly Notices, a journal of Britain's Royal Astronomical Society, German-based scientists Valeri Hambaryan and Ralph Neuhaeuser have come up with a new explanation.

 The pair suggest that two black holes collided and then merged, releasing an intense but extremely brief burst of gamma rays.

 A collision of neutron stars or "white dwarf" stars (tiny, compact stars near the end of their lives) may also have been the cause, say Hambaryan and Neuhaeuser of the University of Jena's Astrophysics Institute.

 Mergers of this kind are often spotted in galaxies other than our own Milky Way, and do not generate visible light.

R.S

Good Bacteria in the Intestine Prevent Diabetes, Study Suggests

All humans have enormous numbers of bacteria and other micro-organisms in the lower intestine. In fact our bodies contain about ten times more bacteria than the number of our own cells and these tiny passengers are extremely important for our health. They help us digest our food and provide us with energy and vitamins. These 'friendly’ commensal bacteria in the intestine help to stop the 'bad guys’ such as Salmonella that cause infections, taking hold. Even the biochemical reactions that build up and maintain our bodies come from our intestinal bacteria as well as our own cells.

Pretty important that we get along with these little bacterial friends... definitely. But as in all beautiful relationships, things can sometimes turn sour. If the bacteria in the intestine become unbalanced, inflammation and damage can occur at many different locations in the body. The best known of these is the intestine itself: the wrong intestinal bacteria can trigger Crohn’s disease and ulcerative colitis. The liver also becomes damaged when intestinal bacteria are unbalanced.

Research groups led by Professor Jayne Danska at the Sick Children’s Hospital of the University of Toronto and Professor Andrew Macpherson in the Clinic for Visceral Surgery and Medicine at the Inselspital and the University of Bern have now shown that the influence of the intestinal bacteria extends even deeper inside the body to influence the likelihood of getting diabetes. In children and young people, diabetes is caused by the immune cells of the body damaging the special cells in the pancreas that produce the hormone insulin. By chance, 30 years ago, before the development of genetic engineering techniques, Japanese investigators noticed that a strain of NOD laboratory mice tended to get diabetes. These mice (also by chance) have many of the same genes that make some humans susceptible to the disease. With the help of the special facilities of the University of Bern and in Canada, these teams have been able to show that the intestinal bacteria, especially in male mice, can produce biochemicals and hormones that stop diabetes developing.

Diabetes in young people is becoming more and more frequent, and doctors even talk about a diabetes epidemic. This increase in diabetic disease has happened over the last 40 years as our homes and environment have become cleaner and more hygienic. At the moment, once a child has diabetes, he or she requires life-long treatment.

"We hope that our new understanding of how intestinal bacteria may protect susceptible children from developing diabetes, will allow us to start to develop new treatments to stop children getting the disease," says Andrew Macpherson of the University Bern.

Source:Science Daily

M.W