Friday, March 5, 2010

SMALL DOGS ORIGINATED IN THE MIDDLE EAST

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A genetic study has found that small domestic dogs probably originated in the Middle East more than 12,000 years ago. Researchers writing in the open access journal BMC Biology traced the evolutionary history of the IGF1 gene, finding that the version of the gene that is a major determinant of small size probably originated as a result of the domestication of the Middle Eastern gray wolf.

Melissa Gray and Robert Wayne, from the University of California, Los Angeles, led a team of researchers who surveyed a large sample of gray wolf populations. She said, "The mutation for small body size post-dates the domestication of dogs. However, because all small dogs possess this variant of IGF1, it probably arose early in their history. Our results show that the version of the IGF1 gene found in small dogs is closely related to that found in Middle Eastern wolves and is consistent with an ancient origin in this region of small domestic dogs".

Previous archeological work in the Middle East has unearthed the remains of small domestic dogs dating to 12,000 years ago. Sites in Belgium, Germany and Western Russia contain older remains (13,000-31,000 years ago), but these are of larger dogs. These findings support the hypothesis put forward by Gray and colleagues that small body size evolved in the Middle East.

Reduction in body size is a common feature of domestication and has been seen in other domesticated animals including cattle, pigs and goats. According to Gray, "Small size could have been more desirable in more densely packed agricultural societies, in which dogs may have lived partly indoors or in confined outdoor spaces".

BioMed Central

CAN MATH AND SCIENCE HELP SOLVE CRIMES?

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UCLA's Jeffrey Brantingham works with the Los Angeles Police Department to analyze crime patterns. He also studies hunter-gatherers in Northern Tibet. If you tell him his research interests sound completely unrelated, he will quickly correct you.

"Criminal offenders are essentially hunter-gatherers; they forage for opportunities to commit crimes," said Brantingham, a UCLA associate professor of anthropology. "The behaviors that a hunter-gatherer uses to choose a wildebeest versus a gazelle are the same calculations a criminal uses to choose a Honda versus a Lexus."

Brantingham has been working for years with Andrea Bertozzi, a professor of mathematics and director of applied mathematics at UCLA, to apply sophisticated math to urban crime patterns. With their colleagues, they have built a mathematical model that allows them to analyze different types of criminal "hotspots" — areas where many crimes occur, at least for a time.

They believe their findings apply not only to Los Angeles but to cities worldwide. Their latest research appeared as the cover feature in the March 2 issue of Proceedings of the National Academy of Sciences (PNAS).

The PNAS paper offers an explanation for when law enforcement officials can expect crime to be suppressed by intensified police actions and when crime might merely be displaced to other neighborhoods.

Crime hotspots come in at least two different types, Brantingham and Bertozzi report in PNAS, along with lead author Martin Short, a UCLA assistant adjunct professor of mathematics, and George Tita, an associate professor of criminology, law and society at UC Irvine. There are hotspots generated by small spikes in crime that grow ("super-critical hotspots") and hotspots where a large spike in crime pulls offenders into a central location ("subcritical hotspots"). The two types look the same from the surface, but they are not.

Policing actions directed at one type of hotspot will have a very different effect from actions directed at the other type.

"This finding is important because if you want the police to suppress the hotspot, you want to be able to later take them out and have the suppression remain," Bertozzi said. "And you can do that with only one of the two, in the subcritical case."

"Unless you are really looking for them, and our model says you should, you would not suspect these two types of hotspots," Brantingham said. "Just by mapping crime and looking at hotspots, you will not be able to know whether that is generated by a small variation in crime or by a big spike in crime.

"If you were to send police into a hotspot without knowing which kind it is, you would not be able to predict whether you will just cause displacement of crime — moving it somewhere else, which is what our model predicts if it's a hotspot generated by small fluctuations in crime — or whether you will actually reduce crime," he said. "Many people have argued that adding police to hotspots will just push crime somewhere else, but that seems not to be true, at least in certain cases. You get displacement in some cases, but not nearly as much as many people thought."

Drug hotspots and violent crime hotspots have been suppressed, and analysts up until now have not been able to explain why.

In their mathematical model, the scientists are able to predict how each type of hotspot will respond to increased policing, as well as when each type might occur, by a careful mathematical analysis involving what is known as bifurcation theory.

"Although this is an idealized model for which all parameters must be known precisely in advance in order to make predictions, we believe this is an important step in understanding why some crime hotspots are merely displaced while others are actually removed by hotspot policing," Bertozzi said.

Predicting crime and devising better crime-prevention strategies requires "a mechanistic explanation for how and why crime occurs where it does and when it does," Brantingham said. "We think we have made a big step in the direction of providing at least one core aspect of that explanation. We will refine it over time. You need to take these initial steps before you can develop new crime-fighting strategies."

Their model, Bertozzi said, "is nonlinear and develops complex patterns in space and time." These features, she noted, are well known in related models in other areas of science.

Bertozzi, Brantingham, Short and Tita have been studying crime patterns in Los Angeles using the last 10 years of data from the LAPD and have been able to identify violent crime hotspots, burglary hotspots and auto-theft hotspots, among others. They believe their analysis likely applies to a wide variety of crimes.

The research is federally funded by the National Science Foundation (www.nsf.gov) and the U.S. Department of Defense.

"We have a key to understanding real-world phenomena," Bertozzi said. "The key is the mathematics. With powerful mathematical tools, we can borrow methods that have been studied in great detail for other areas of science and engineering and figure out how to apply them to very different problems, such as crime patterns."

Will their research actually help police departments reduce crime?

"We're cautiously optimistic," Brantingham said. "Good science is done in small, incremental steps that can lead to big benefits in the long term. We are trying to understand the dynamics of crime and to make small but significant steps in helping our police partners come up with policing strategies that will help to reduce crime.

"We have to do what biologists and engineers have been doing for years, which is to try to understand the fundamental mechanics and dynamics of how a system works," he said. "Before you can make predictions about how the system will behave, you have to understand the fundamental dynamics. That's true with weather forecasting, where you run a climate simulation, and true with crime patterns."

The LAPD is at the world's forefront of knowing where crime is occurring and responding very quickly, Brantingham said.

"Can we actually push policing to look into the future and make a reasonable prediction about the near term when deciding how to allocate resources?" Brantingham asked. "This is the type of research that is necessary to make that a reality."

Why do criminals return to the scene of a crime, or at least the same general area?

"If my house is burglarized today, then it is more likely to be burglarized tomorrow as well," said Short, who has studied problems involving mathematical modeling and pattern formation. "There are good reasons for repeat victimization, from a criminal's point of view. They have already broken into your house once, so they know how to get in, and they already know what you have in your house. The data back this up.

"The 'near repeat effect' says not only is my house more likely to be burglarized again, but so are my neighbors' homes," Short added. "The burglar may be comfortable with that area. It may be near where he lives."

The scientists are also studying crime patterns with the mathematics used to forecast earthquakes and their aftershocks. "They are actually very similar," Bertozzi said.

In addition, they have started studying whether patterns of gang violence in Los Angeles are similar to insurgent killings in Iraq.

"An insurgent who wants to place an improvised explosive device in a particular location will make the same kind of calculations that a car thief will use in choosing which car to steal," Brantingham said. "They want to go into areas where they feel comfortable, where they know the nooks and crannies. They want to be in an area where their activities will not appear suspicious. They also want to have a large impact.

"The same thing goes for a burglar trying to break into a house or a car thief or a guy looking for a bar fight," he said. "They want to go where they know they can go in and out without seeming too suspicious and where they can get the biggest bang for their buck. The mathematics underlying the insurgent activity and the criminal activity is very much the same. We're studying that now."

The researchers have funding from the U.S. Army Research Office's mathematics division to compare Iraq data and gang data.

They have also started a research project with the U.S. Office of Naval Research to provide mathematical algorithms that can help them extract information from diverse data sets.

Why is an anthropologist collaborating on a mathematical model to analyze human behavior?

"Many social scientists say human behavior and criminal behavior are too complex to be explained with a mathematical model," said Brantingham, who was trained as an archaeologist. "But it's not too complex. We're not trying to explain everything, but there are many aspects of human behavior that are easily understood in a formal mathematical structure. There are regularities to human behavior that we can understand mathematically."

"We're not asking whether a particular individual is going to commit a crime," Bertozzi said. "We ask whether a particular neighborhood will see an increase in crime."

It's a matter of group behavior, like studying traffic flow patterns, she said.

"Mathematical models and differential equations have been used in that field for decades," said Bertozzi, who had not worked with social scientists before working with Brantingham.

She is interested in applying mathematics to address practical problems that affect peoples' lives.

"This is an exciting area of research," she said. "UCLA has one of the top applied mathematics programs in the country, and we are able to attract stellar graduate students, postdoctoral researchers and young faculty, such as Martin Short, who have made a huge impact in this research."

Bertozzi and Brantingham began working together after meeting through UCLA's Institute for Pure and Applied Mathematics.

"I knew if we were going to study crime problems, we needed excellent sources of data," Bertozzi said. "The fact that Jeff had the connection with LAPD and many interesting classes of problems to study intrigued me."

Bertozzi and Brantingham, along with George Tita and Lincoln Chayes, a UCLA professor of mathematics, wrote a proposal to the National Science Foundation to support the research, which was funded.

"A lot of what motivated me to look at crime initially was trying to take the approaches to understanding the physical world I learned in archaeology and applying it to contemporary problems such as crime," Brantingham said. "With George Tita and others, we reached out to the LAPD, and they have been very supportive of our work."

(Photo: UCLA)

UCLA

NANOTECHNOLOGY SPARKS ENERGY STORAGE ON PAPER AND CLOTH

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By dipping ordinary paper or fabric in a special ink infused with nanoparticles, Stanford engineer Yi Cui has found a way to cheaply and efficiently manufacture lightweight paper batteries and supercapacitors (which, like batteries, store energy, but by electrostatic rather than chemical means), as well as stretchable, conductive textiles known as "eTextiles" – capable of storing energy while retaining the mechanical properties of ordinary paper or fabric.

While the technology is still new, Cui's team has envisioned numerous functional uses for their inventions. Homes of the future could one day be lined with energy-storing wallpaper. Gadget lovers would be able to charge their portable appliances on the go, simply plugging them into an outlet woven into their T-shirts. Energy textiles might also be used to create moving-display apparel, reactive high-performance sportswear and wearable power for a soldier's battle gear.

The key ingredients in developing these high-tech products are not visible to the human eye. Nanostructures, which can be assembled in patterns that allow them to transport electricity, may provide the solutions to a number of problems encountered with electrical storage devices currently available on the market.

The type of nanoparticle used in the Cui group's experimental devices varies according to the intended function of the product – lithium cobalt oxide is a common compound used for batteries, while single-walled carbon nanotubes, or SWNTs, are used for supercapacitors.

Cui, an assistant professor of materials science and engineering at Stanford, leads a research group that investigates new applications of nanoscale materials. The objective, said Cui, is not only to supply answers to theoretical inquiries but also to pursue projects with practical value. Recently, his team has focused on ways to integrate nanotechnology into the realm of energy development.

"Energy storage is a pretty old research field," said Cui. "Supercapacitors, batteries – those things are old. How do you really make a revolutionary impact in this field? It requires quite a dramatic difference of thinking."

While electrical energy storage devices have come a long way since Alessandro Volta debuted the world's first electrical cell in 1800, the technology is facing yet another revolution. Current methods of manufacturing energy storage devices can be capital intensive and environmentally hazardous, and the end products have noticeable performance constraints – conventional lithium ion batteries have a limited storage capacity and are costly to manufacture, while traditional capacitors provide high power but at the expense of energy storage capacity.

With a little help from new science, the batteries of the future may not look anything like the bulky metal units we've grown accustomed to. Nanotechnology is favored as a remedy both for its economic appeal and its capability to improve energy performance in devices that integrate it. Replacing the carbon (graphite) anodes found in lithium ion batteries with anodes of silicon nanowires, for example, has the potential to increase their storage capacity by 10 times, according to experiments conducted by Cui's team.

Silicon had previously been recognized as a favorable anode material because it can hold a larger amount of lithium than carbon. But applications of silicon were limited by its inability to sustain physical stress – namely, the fourfold volume increase that silicon undergoes when lithium ions attach themselves to a silicon anode in the process of charging a battery, as well as the shrinkage that occurs when lithium ions are drawn out as it discharges. The result was that silicon structures would disintegrate, causing anodes of this material to lose much if not all of their storage capacity.

Cui and collaborators demonstrated in previous publications in Nature, Nanotechnology and Nano Letters that the use of silicon nanowire battery electrodes, mechanically capable of withstanding the absorption and discharge of lithium ions, was one way to sidestep the problem.

The findings hold promise for the development of rechargeable lithium batteries offering a longer life cycle and higher energy capacity than their contemporaries. Silicon nanowire technology may one day find a home in electric cars, portable electronic devices and implantable medical appliances.

Cui now hopes to direct his research toward studying both the "hard science" behind the electrical properties of nanomaterials and designing real-world applications.

"This is the right time to really see what we learn from nanoscience and do practical applications that are extremely promising," said Cui. "The beauty of this is, it combines the lowest cost technology that you can find to the highest tech nanotechnology to produce something great. I think this is a very exciting idea … a huge impact for society."

(Photo: L.A. Cicero)

Stanford University

OPTICAL SYSTEM PROMISES TO REVOLUTIONIZE UNDERSEA COMMUNICATIONS

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In a technological advance that its developers are likening to the cell phone and wireless Internet access, Woods Hole Oceanographic Institution (WHOI) scientists and engineers have devised an undersea optical communications system that—complemented by acoustics—enables a virtual revolution in high-speed undersea data collection and transmission.

Along with the “transfer [of] real-time video from un-tethered [submerged] vehicles” up to support vessels on the surface, “this combination of capabilities will make it possible to operate self-powered ROVs [remotely operate vehicles] from surface vessels without requiring a physical connection to the ROV,” says WHOI Senior Engineer Norman E. Farr, who led the research team. This will not only represent a significant technological step forward, but also promises to reduce costs and simplify operations, they say.

Compared to communication in the air, communicating underwater is severely limited because water is essentially opaque to electromagnetic radiation except in the visible band. Even then, light penetrates only a few hundred meters in the clearest waters; less in sediment-laden or highly populated waters.

Consequently, acoustic techniques were developed, and are now the predominant mode of underwater communications between ships and smaller, autonomous and robotic vehicles. However, acoustic systems—though capable of long-range communication—transmit data at limited speeds and delayed delivery rates due to the relatively slow speed of sound in water.

Now, Farr and his WHOI team have developed an optical communication system that complements and integrates with existing acoustic systems to enable data rates of up to 10-to-20 megabits per second over a range of 100 meters using relatively low battery power with small, inexpensive transmitters and receivers.

The advance will allow near-instant data transfer and real-time video from un-tethered ROVs and autonomous underwater vehicles (AUVs) outfitted with sensors, cameras and other data-collecting devices to surface ships or laboratories, which would require only a standard UNOLS cable dangling below the surface for the relaying of data.

This would represent a significant advance, Farr says, in undersea investigations of anything from the acidity of water to indentifying marine life to observing erupting vents and seafloor slides to measuring numerous ocean properties. In addition, the optical system would enable direct maneuvering of the vehicle by a human.

He likens optical/acoustic system possibilities to the world opened up by “your household wi-fi.”

Co-investigator Maurice Tivey of WHOI adds that “underwater optical communications is akin to the cell phone revolution…wireless communications. The ability to transfer information and data underwater without wires or plugging cables in is a tremendous capability allowing vehicles or ships to communicate with sensors on the seafloor.

“While acoustic communications has been the method of choice in the past it is limited by bandwidth and the bulkiness of transducers,” Tivey says. “Today, sensors sample at higher rates and can store lots of data and so we need to be able to download that data more efficiently. Optical communications allows us to transfer large data sets, like seismic data or tides or hydrothermal vent variations, in a time-efficient manner.”

When the vehicle goes out of optical range, it will still be within acoustic range, the researchers said.

Because it enables communications without the heavy tether-handling equipment required for an ROV, the optical/acoustic system promises to require smaller, less-expensive ships and fewer personnel to perform undersea missions, Farr said.

This July, WHOI plans the first large-scale deployment of the system at the Juan de Fuca Ridge off shore of the Northwestern United States. The WHOI team will employ the human occupied vehicle (HOV) Alvin to deploy the optical system on a sub sea data concentrator to collect and transmit geophysical data from wellheads situated at the undersea ridge.

Ultimately, Farr says, the system will “allow us to have vehicles [at specific undersea locations] waiting to respond to an event. It’s a game-changer.”

(Photo: E. Paul Oberlander, Woods Hole Oceanographic Institution)

Woods Hole Oceanographic Institution

THICKER BRAINS FEND OFF PAIN

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People can reduce their sensitivity to pain by thickening their brain, according to a new study published in a special issue of the American Psychological Association journal, Emotion. Researchers from the Université de Montréal made their discovery by comparing the grey matter thickness of Zen meditators and non-meditators. They found evidence that practicing the centuries-old discipline of Zen can reinforce a central brain region (anterior cingulate) that regulates pain.

"Through training, Zen meditators appear to thicken certain areas of their cortex and this appears to be underlie their lower sensitivity to pain," says lead author Joshua A. Grant, a doctoral student in the Université de Montréal Department of Physiology and Institut universitaire de gériatrie de Montréal. "We found a relationship between cortical thickness and pain sensitivity, which supports our previous study on how Zen meditation regulates pain."

As part of this study, scientists recruited 17 meditators and 18 non-meditators who in addition had never practiced yoga, experienced chronic pain, neurological or psychological illness. Grant and his team, under the direction of Pierre Rainville of the Université de Montréal and the Institut universitaire de gériatrie de Montréal, measured thermal pain sensitivity by applying a heated plate to the calf of participants and followed by scanning the brains of subjects with structural magnetic resonance imaging. According to MRI results, central brain regions that regulate emotion and pain were significantly thicker in meditators compared to non-meditators.

"The often painful posture associated with Zen meditation may lead to thicker cortex and lower pain sensitivity," says Grant, noting that meditative practices could be helpful in general for pain management, for preventing normal age-related grey matter reductions or potentially for any condition where the grey matter is compromised such as stroke.

(Photo: IStock)

Université de Montréal

AN EMOTION DETECTOR FOR BABY

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Baby monitors of the future could translate infant cries, so that parents will know for certain whether their child is sleepy, hungry, needing a change, or in pain. Japanese scientists report details of a statistical computer program that can analyze a baby's crying in the International Journal of Biometrics.

As any new parent knows, babies have a very loud method of revealing their emotional state - crying. Unfortunately, the parenting handbook does not offer guidance on how to determine what the crying means. Parents sometimes learn with experience that their child's cries may be slightly different depending on their cause, whether hunger or discomfort.

Now, engineers in Japan have turned to an approach to product design, known as kansei engineering, invented in the 1970s by Professor Mitsuo Nagamachi, Dean of Hiroshima International University, which aims to "measure" feelings and emotions.

Tomomasa Nagashima of the Department of Computer Science and Systems Engineering, at Muroran Institute of Technology, in Hokkaido and colleagues explain that the fundamental problem in building an emotion detector for baby's crying is that the baby cannot confirm verbally what its cries mean. Various researchers have tried to classify infant emotions based on an analysis of the crying pattern but with little success so far.

The team has employed sound pattern recognition approach that uses a statistical analysis of the frequency of cries and the power function of the audio spectrum to classify different types of crying. They were then able to correlate the different recorded audio spectra with a baby's emotional state as confirmed by the child's parents. In their tests recordings of crying babies with a painful genetic disorder, were used to make differentiating between the babies' pained cries and other types of crying more obvious. They achieved 100% success rate in a validation to classify pained cries and "normal" cries.

The research has developed a sound theoretical method for classification of infant emotions, although limited to a specific emotion, based on analysis of the audio spectra of the baby's cries. The technique might one day be incorporated into a portable electronic device, or app, to help parents or carers decide on a course of action when their child is crying.

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