Most of the concerns about climate change have focused on the amount of greenhouse gases that have been released into the atmosphere.

But in a new study published in Science, a group of Rutgers researchers have found that circulation of the ocean plays an equally important role in regulating the earth’s climate.

In their study, the researchers say the major cooling of Earth and continental ice build-up in the Northern Hemisphere 2.7 million years ago coincided with a shift in the circulation of the ocean – which pulls in heat and carbon dioxide in the Atlantic and moves them through the deep ocean from north to south until it’s released in the Pacific.

The ocean conveyor system, Rutgers scientists believe, changed at the same time as a major expansion in the volume of the glaciers in the northern hemisphere as well as a substantial fall in sea levels. It was the Antarctic ice, they argue, that cut off heat exchange at the ocean’s surface and forced it into deep water. They believe this caused global climate change at that time, not carbon dioxide in the atmosphere.

“We argue that it was the establishment of the modern deep ocean circulation – the ocean conveyor – about 2.7 million years ago, and not a major change in carbon dioxide concentration in the atmosphere that triggered an expansion of the ice sheets in the northern hemisphere,” says Stella Woodard, lead author and a post-doctoral researcher in the Department of Marine and Coastal Sciences. Their findings, based on ocean sediment core samples between 2.5 million to 3.3 million years old, provide scientists with a deeper understanding of the mechanisms of climate change today.

The study shows that changes in heat distribution between the ocean basins is important for understanding future climate change. However, scientists can’t predict precisely what effect the carbon dioxide currently being pulled into the ocean from the atmosphere will have on climate. Still, they argue that since more carbon dioxide has been released in the past 200 years than any recent period in geological history, interactions between carbon dioxide, temperature changes and precipitation, and ocean circulation will result in profound changes.

Scientists believe that the different pattern of deep ocean circulation was responsible for the elevated temperatures 3 million years ago when the carbon dioxide level in the atmosphere was arguably what it is now and the temperature was 4 degree Fahrenheit higher. They say the formation of the ocean conveyor cooled the earth and created the climate we live in now.

“Our study suggests that changes in the storage of heat in the deep ocean could be as important to climate change as other hypotheses – tectonic activity or a drop in the carbon dioxide level – and likely led to one of the major climate transitions of the past 30 million years,” says Yair Rosenthal, co-author and professor of marine and coastal sciences at Rutgers

The paper’s co-authors are Woodard, Rosenthal, Kenneth Miller and James Wright, both professors of earth and planetary sciences in the School of Arts and Sciences at Rutgers; Beverly Chiu, a Rutgers undergraduate majoring in earth and planetary sciences; and Kira Lawrence, associate professor of geology at Lafayette College in Easton, Pennsylvania.

An international team of researchers has discovered a new signaling molecule capable of activating brown fat cells.

The number of overweight persons is greatly increasing worldwide – and as a result is the risk of suffering a heart attack, stroke, diabetes or Alzheimer’s disease. For this reason, many people dream of an efficient method for losing weight. An international team of researchers led by Professor Alexander Pfeifer from the University Hospital Bonn, have now come one step closer to this goal. The scientists discovered a new way to stimulate brown fat and thus burn energy from food: The body’s own adenosine activates brown fat and “browns” white fat. The results are now being published in the journal Nature.

“Not all fat is equal,” says Professor Alexander Pfeifer from the Institute of Pharmacology and Toxicology of the University Hospital Bonn. Humans have two different types of fat: undesirable white fat cells which form bothersome “love handles”, for example, as well as brown fat cells, which act like a desirable heater to convert excess energy into heat. “If we are able to activate brown fat cells or to convert white fat cells into brown ones, it might be possible to simply melt excess fat away” reports the pharmacologist.

The group of Prof. Pfeifer together with an international team from Sweden, Denmark, Finland, as well as from the Helmholtz-Center Dresden-Rossendorf and the University of Düsseldorf now discovered a new signaling molecule capable of activating brown fat cells: adenosine. Adenosine is typically released during stress. Crucial for transmitting the adenosine signal is the adenosine receptor A2A.

Adenosine activates brown adipose tissue

“If adenosine binds to this receptor in brown fat cells, fat burning is significantly stimulated,” reports Dr. Thorsten Gnad from Prof. Pfeifer’s team. It was previously thought not possible for adenosine to activate brown fat. Several studies with rats and hamsters demonstrated that adenosine blocks brown fat.

However, the researchers from the University of Bonn were not mislead by these previous findings. In contrast, using brown fat cells removed from humans during surgery, the scientists investigated the signaling pathway for fat activation using adenosine. The results showed that rats and hamsters react differently than humans in this regard. “The brown fat in mice on the other hand behaves just as in humans,” summarizes Prof. Pfeifer.

“Browning” of white fat by adenosine

In addition, the research team investigated the possibility that adenosine transforms white fat cells into brown fat cells – a process termed “browning”. White fat cells normally cannot be induced to burn excess fat by adenosine, as they simply lack the A2A receptor. For this reason, the team of scientists transferred the A2A receptor gene from brown fat cells to white fat cells in mice. Consequently, the white fat cells also have A2A receptors and start browning and burning energy.

Clinical application is still far off

Based on a rigorous comparative analysis of kangaroo anatomy, biologists at Brown University reveal that the ancient family of sthenurine kangaroos likely preferred walking to hopping.

Imagine that a time machine has transported you to the Australian outback 100,000 years ago. As you emerge, you see a huge kangaroo with a round rabbit-like face foraging in a tall bush nearby. The animal’s surprising size makes you gasp aloud but when it hears you, becoming equally unnerved, it doesn’t hop or lumber away on all fours and tail like every kangaroo you’ve seen in the present. It walks on its feet. One at a time. Like you.

In a new paper in the journal PLoS ONE, a team of researchers led by Christine Janis, professor of ecology and evolutionary biology at Brown University, posits that the Pleistocene members of the now extinct family of sthenurine kangaroos were likely bipedal walkers. The scientists make their case based on a rigorous statistical and biomechanical analysis of the bones of sthenurines and other kangaroos past and present. In all, they made nearly 100 measurements on each of more than 140 individual kangaroo and wallaby skeletons from many genera and species.

The investigation started in 2005 with a moment of intuition. Janis, an expert on the anatomy of other bygone Australian beasts such as the thylacine, was visiting a museum with a colleague. She beheld a sthenurine skeleton that displayed, among other traits, a sturdy rather than flexible-looking, spine. She began to wonder if it moved the same way modern, familiar kangaroos do.

Janis and co-authors Karalyn Kuchenbecker, a former Brown undergraduate, and Borja Figuerido, of the University of Malaga, Spain, then spent years working to determine how sthenurines, known as “short-faced, giant kangaroos,” likely got around.

In the ensuing measurements and statistical analyses described in the paper, the researchers found many reasons to hypothesize that for locomotion, stheneurines were fundamentally unlike the large modern red and grey kangaroos – the modern-day favorites of zoo-goers. On statistical plots charting trait after trait of hind limb bones, sthenurines consistently stood apart from their hopping cousins. Other researchers had already noted other differences — sthenurines had teeth for browsing for food, for example, rather than grazing, like the large kangaroos of today.

From a biomechanical standpoint, the anatomy of all sizes of sthenurines would have made them poor hoppers, the researchers found. For the especially giant species, one of which may have weighed as much as 550 pounds, hopping might have been very hard to do.

“I don’t think they could have gotten that large unless they were walking,” Janis said.

Today’s kangaroos hop at fast speeds and move about on all fours for slow speed travel (or, as a recent paper noted, “pentapedally,” which means on all fours plus the tail). This requires a flexible backbone, sturdy tail, and hands that can support their body weight. Sthenurines don’t appear to have had any of those attributes.

Whether any of the sthenurines still hopped to attain fast speeds, Janis said, bipedal walking was much more likely to be at least their mode of slow speed locomotion. Indeed, the researchers found multiple lines of evidence suggesting that sthenurines were much better suited than extant kangaroos to put their weight on one foot at a time, a requirement for walking. The only possible example of walking in living kangaroos, Janis said, are anecdotal reports of it in tree kangaroos.

Anatomy for ambling

The paper offers many examples of how sthenurines were anatomically ill-suited for hopping but well suited for bearing weight on one leg at a time.

Take, for one example, the evidence from the ankles of sthenurines. In walking and running animals such as horses and dogs, the lower end of the tibia has a flange that wraps over the back of the joint, providing extra stability to support more weight on each ankle. Living kangaroos, who almost always distribute their weight over both feet equally, don’t have that flange, but sthenurines did.

Sthenurines had proportionally bigger hip and knee joints. The shape of the pelvis differs importantly as well. The sthenurines had a broad and flared pelvis that would have allowed for proportionally much larger gluteal muscles than other kangaroos. Those muscles would have allowed them to balance weight over just one leg at a time, as do the large gluteals of humans during walking.

In much of their skeletons, the analysis showed, sthenurines were proportionally more “robust” (big-boned) than the rather slender-boned large living kangaroos.

In looking at overall kangaroo anatomy through history, Janis said, the analysis revealed that, if anything, the large kangaroos that are the “weird” ones are actually the living red and gray kangaroos, because they are proportionally very lightly built for their size (like cheetahs among cats).

Previous researchers had already observed that sthenurines’ hands were ill-suited for supporting the kangaroo for all-fours but were instead specialized for foraging. That also helps to rule out the idea that sthenurines would have gotten far on all fours or pentapedally.

And then there was Janis’ observation of the relatively inflexible spine, which has also noted by others. These and many other observations suggest that hopping or pentapedal locomotion would have been difficult, Janis said, but walking would not have been.

“If it is not possible in terms of biomechanics to hop at very slow speeds, particularly if you are a big animal, and you cannot easily do pentapedal locomotion, then what do you have left?” Janis reasoned. “You’ve got to move somehow.”

Whether the reliance on walking, which isn’t as fast as efficient or as suited for long distances as hopping, explains why sthenurines became extinct about 30,000 years ago is unknown, Janis said. They might have struggled to elude human hunters, she said, or they might have been unable to migrate far enough to find food as climate became more arid.

The hypothesis that sthenurines were walkers would still benefit from other lines of evidence, Janis acknowledged, such the discovery of preserved tracks.

White House officials say technicians recently noticed suspicious activity on the computer systems at the U.S. presidential mansion.

They say the situation was dealt with immediately and work continues, although the response has led to temporary outages and loss of Internet connectivity for some White House employees.

Officials gave no details about who might who have been responsible or when the activity occurred.

An unmanned commercial rocket that was supposed to send a cargo ship to the International Space Station exploded Tuesday, six seconds after liftoff from a NASA launch pad in Virginia.

The privately owned rocket barely got off the ground before it blew up just after sunset on Wallops Island, off the Atlantic coast.

There was no one on board and no one on the ground was hurt.  All the damage was limited to the so-called hazard area.  Officials say the investigation has already begun.

A number of still photographs taken on October 23, in the lead up to the Antares rocket launch, show a number of final checks being undertaken on the Cygnus spacecraft.

The pictures, supplied by NASA, show Orbital Sciences Corp. completing the final cargo load ahead of Tuesday's launch and the Orb-3 Mission's payload fairing, or casing, around the Cygnus spacecraft, being installed.

The accident is the first since NASA turned to private operators to deliver cargo to the International Space Station.

The six crew members in orbit aboard the space station - two NASA astronauts, one from the European Space Agency and three Russian cosmonauts - watched the launch via a NASA TV feed, said Mike Suffredini, the space station program manager.

With a Russian cargo ship due to reach the space station on Wednesday, just 14 hours after the explosion in Virginia, the loss of the Cygnus vessel posed no immediate problem for the orbiting team.

Orbital Sciences stock fell 15.5 percent to a two-month low of $25.65 in after-hours trading.

The cause of the mishap was under investigation, said Frank Culbertson, Orbital Sciences executive vice president.

NASA official William Gerstenmaier says launching rockets is a really tough and demanding business, but that NASA has confidence in the company.