Wednesday, September 8, 2010



Download Manga Fairy Tail chapter 199 English with title "LISANNA", scanlation original by Mangastream / Binktopia

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Saturday, September 4, 2010

Danger in the Internet Cafe? New Computer Security Threat for Wireless Networks: Typhoid Adware

John Aycock (left) and student Daniel Medeiros Nunes de Castro have predicted a new computer security threat: Typhoid adware.

There's a potential threat lurking in your internet café, say University of Calgary computer science researchers. It's called Typhoid adware and works in similar fashion to Typhoid Mary, the first identified healthy carrier of typhoid fever who spread the disease to dozens of people in the New York area in the early 1900s.

Computers & Math

* Internet
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Science & Society

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* Malware
* Spyware
* User interface design
* Local area network

"Our research describes a potential computer security threat and offers some solutions," says associate professor John Aycock, who co-authored a paper with assistant professor Mea Wang and students Daniel Medeiros Nunes de Castro and Eric Lin. "We're looking at a different variant of adware -- Typhoid adware -which we haven't seen out there yet, but we believe could be a threat soon."

Adware is software that sneaks onto computers often when users download things, for example fancy tool bars or free screen savers, and it typically pops up lots and lots of ads. Typhoid adware needs a wireless internet café or other area where users share a non-encrypted wireless connection.

"Typhoid adware is designed for public places where people bring their laptops," says Aycock. "It's far more covert, displaying advertisements on computers that don't have the adware installed, not the ones that do."

The paper demonstrates how Typhoid adware works as well as presents solutions on how to defend against such attacks. De Castro recently presented it at the EICAR conference in Paris, a conference devoted to IT security.

Typically, adware authors install their software on as many machines as possible. But Typhoid adware comes from another person's computer and convinces other laptops to communicate with it and not the legitimate access point. Then the Typhoid adware automatically inserts advertisements in videos and web pages on the other computers. Meanwhile, the carrier sips her latté in peace -- she sees no advertisements and doesn't know she is infected ¬- just like symptomless Typhoid Mary.

U of C researchers have come up with a number of defenses against Typhoid adware. One is protecting the content of videos to ensure that what users see comes from the original source. Another is a way to "tell" laptops they are at an Internet café to make them more suspicious of contact from other computers.

"When you go to an Internet café, you tell your computer you are there and it can put up these defenses. Anti-virus companies can do the same thing through software that stops your computer from being misled and re-directed to someone else," says Aycock.

Why worry about ads? Aycock explains it this way: "Not only are ads annoying but they can also advertise rogue antivirus software that's harmful to your computer, so ads are in some sense the tip of the iceberg."

The paper Typhoid Adware can be found:
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'Biosensors' on Four Feet Detect Animals Infected With Bird Flu

mouse earns a water reward for choosing the odor of samples of feces infected with avian flu over a feces sample from ducks that were not infected.

Blood hounds, cadaver dogs, and other canines who serve humanity may soon have a new partner ― disease detector dogs ― thanks to an unusual experiment in which scientists trained mice to identify feces of ducks infected with bird influenza. Migrating ducks, geese, and other birds can carry and spread flu viruses over wide geographic areas, where the viruses may possibly spread to other species.
Reported in Boston at the 240th National Meeting of the American Chemical Society (ACS), the proof-of-concept study may pave the way for development of biosensors-on-four-feet that warn of infection with influenza and other diseases.

"Based on our results, we believe dogs, as well as mice, could be trained to identify a variety of diseases and health conditions," said U.S. Department of Agriculture scientist Bruce A. Kimball, Ph.D., who presented the study results. The study was among nearly 8,000 scientific reports scheduled for presentation at the ACS meeting, one of the largest scientific gatherings of 2010.

"In fact, we envision two broad, real-world applications of our findings," Kimball added. "First, we anticipate use of trained disease-detector dogs to screen feces, soil, or other environmental samples to provide us with an early warning about the emergence and spread of flu viruses. Second, we can identify the specific odor molecules that mice are sensing and develop laboratory instruments and in-the-field detectors to detect them."

Kimball cited the likelihood that a suite of chemicals, rather than a single compound, are responsible for producing the difference in fecal odor between healthy and infected ducks. His team is investigating the use of instruments in detecting these so-called volatile, or gaseous, metabolites in animal feces. Once accomplished, they can use statistical techniques to sift through the data to determine the pattern of volatiles that indicate the presence of infection.

Kimball and colleagues from the Monell Chemical Senses Center trained inbred mice to navigate a maze and zero in on infected duck feces. The mice got a reward of water every time they correctly identified the infected sample and no reward when they zeroed in on feces from healthy ducks. Eventually, the mice became experts at identifying feces from infected ducks.
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Magnetism's Subatomic Roots: Study of High-Tech Materials Helps Explain Everyday Phenomenon

A new theoretical physics model helps define the subatomic origins of ferromagnetism -- the everyday "magnetism" of compass needles and refrigerator magnets.

The modern world -- with its ubiquitous electronic devices and electrical power -- can trace its lineage directly to the discovery, less than two centuries ago, of the link between electricity and magnetism. But while engineers have harnessed electromagnetic forces on a global scale, physicists still struggle to describe the dance between electrons that creates magnetic fields.
Two theoretical physicists from Rice University are reporting initial success in that area in a new paper in the Proceedings of the National Academy of Sciences. Their new conceptual model, which was created to learn more about the quantum quirks of high-temperature superconductors and other high-tech materials, has also proven useful in describing the origins of ferromagnetism -- the everyday "magnetism" of compass needles and refrigerator magnets.

"As a theorist, you strive to have exact solutions, and even though our new model is purely theoretical, it does produce results that match what's observed in the real world," said Rice physicist Qimiao Si, the lead author of the paper. "In that sense, it is reassuring to have designed a model system in which ferromagnetism is allowed."

Ferromagnets are what most people think of as magnets. They're the permanently magnetic materials that keep notes stuck to refrigerators the world over. Scientists have long understood the large-scale workings of ferromagnets, which can be described theoretically from a coarse-grained perspective. But at a deeper, fine-grained level -- down at the scale of atoms and electrons -- the origins of ferromagnetism remain fuzzy.

"When we started on this project, we were aware of the surprising lack of theoretical progress that had been made on metallic ferromagnetism," Si said. "Even a seemingly simple question, like why an everyday refrigerator magnet forms out of electrons that interact with each other, has no rigorous answer."

Si and graduate student Seiji Yamamoto's interest in the foundations of ferromagnetism stemmed from the study of materials that were far from ordinary.

Si's specialty is an area of condensed matter physics that grew out of the discovery more than 20 years ago of high-temperature superconductivity. In 2001, Si offered a new theory to explain the behavior of the class of materials that includes high-temperature superconductors. This class of materials -- known as "quantum correlated matter" -- also includes more than 10 known types of ferromagnetic composites.

Si's 2001 theory and his subsequent work have aimed to explain the experimentally observed behavior of quantum-correlated materials based upon the strangely correlated interplay between electrons that goes on inside them. In particular, he focuses on the correlated electron effect that occur as the materials approach a "quantum critical point," a tipping point that's the quantum equivalent of the abrupt solid-to-liquid change that occurs when ice melts.

The quantum critical point that plays a key role in high-temperature superconductivity is the tipping point that marks a shift to antiferromagnetism, a magnetic state that has markedly different subatomic characteristics from ferromagnetism. Because of the key role in high-temperature superconductivity, most studies in the field have focused on antiferromagnetism. In contrast, ferromagnetism -- the more familiar, everyday form of magnetism -- has received much less attention theoretically in quantum-correlated materials.

"So our initial theoretical question was, 'What would happen, in terms of correlated electron effects, when a ferromagnetic material moves through one of these quantum tipping points?" said Yamamoto, who is now a postdoctoral researcher at the National High Magnetic Field Laboratory in Tallahassee, Fla..

To carry out this thought experiment, Si and Yamamoto created a model system that idealizes what exists in nature. Their jumping off point was a well-studied phenomenon known as the Kondo effect -- which also has its roots in quantum magnetic effects. Based on what they knew of this effect, they created a model of a "Kondo lattice," a fine-grained mesh of electrons that behaved like those that had been observed in Kondo studies of real-world materials.

Si and Yamamoto were able to use the model to provide a rigorous answer about the fine-grained origins of metallic ferromagnetism. Furthermore, the ferromagnetic state that was predicted by the model turned out to have quantum properties that closely resemble those observed experimentally in heavy fermion ferromagnets.

"The model is useful because it allows us to predict how real-world materials might behave under a specific set of circumstances," Yamamoto said. "And, in fact, we have been able to use it to explain experimental observations on heavy fermion metals, including both the antiferromagnets as well as the less well understood ferromagnetic materials."
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Hovering Bats Stay Aloft Using Swirling Vortices

Simplified representation of the strong vortices associated with the unsteady aerodynamics of bat flight at slow speeds. The vortices can be thought of as causing the surrounding air to rotate rapidly around them, and this motion around the LEV on top of the wing increases the lift force on it. Just like familiar, fixed-wing planes, the bat also leaves tip vortices in its wake, but the overall flow is further modified by the start vortices created at the beginning of the downstroke. (Credit: Image courtesy of University of Southern California)

Honey bees and hummingbirds can hover like helicopters for minutes at a time, sucking the juice from their favorite blossoms while staying aloft in a swirl of vortices.
But the unsteady air flows they create for mid-air suspension – which hold the secrets to tiny robotic flying machines -- have also been observed for the first time in the flight of larger and heavier animals, according to Prof. Geoffrey Spedding of the Department of Aerospace and Mechanical Engineering at the University of Southern California and his colleagues at Lund University, Sweden.

In a follow-up study of bat aerodynamics, appearing in the February 29, 2008 issue of Science, Spedding and co-authors F. T. Muijres, L.C. Johansson, R. Barfield, M. Wolf and A. Hedenstrom were able to measure the velocity field immediately above the flapping wings of a small, nectar-eating bat as it fed freely from a feeder in a low-turbulence wind tunnel.

Researchers used a wind tunnel at Lund University specially crafted for research on bird flight on bats. Birds fly “at the spot” against a headwind, allowing detailed investigation of wing movements using high speed video cameras. It’s also possible to visualize the vortices around the wings and in the wake using fog as tracer particles.

“Thanks to a very reliable behavior pattern where bats learned to feed at a thin, sugar-filled tube in the wind tunnel, using the same flight path to get there every time, and the construction of side flaps on the feeder tube, we could make observations with bright laser flashes right at mid-wing without harming the bats,” Spedding reported in a commentary about the study. “Before this, we had no direct evidence of how the air moved over the wing itself in these small vertebrates.”

The researchers’ findings challenge quasi-steady state aerodynamic theory, which suggests that slow-flying vertebrates should not be able to generate enough lift to stay above ground, said Spedding, a professor of aerospace and mechanical engineering in the USC Viterbi School of Engineering.

Using digital particle image velocimetry, the researchers discovered that Pallas’ long-tongued bat, Glossophaga soricina, increased its lift by as much as 40 percent using a giant and apparently stable, re-circulating zone, known as a leading-edge vortex (LEV), which completely changed the effective airfoil shape.

How can the bats generate such high lift? One of the team members and lead author of the new study, Florian Muijres, explains: "The high lift arises because the bats can actively change the shape (curvature) by their elongated fingers and by muscle fibers in their membranous wing. A bumblebee cannot do this; its wings are stiff. This is compensated for by the wing-beat frequency. Bats beat their wings up to 17 times per second while the bumblebee can approach 200 wing-beats per second."

“The air flow passing over the LEV of a flapping wing left an amazingly smooth and ordered laminar disturbance at the trailing edge of the wing, and the LEV itself accounted for at least a 40 percent increment in lift,” Spedding noted in his commentary, “Leading Edge Vortex Improves Lift in Slow-Flying Bats.” The LEV makes a strong lift force, but it may be equally important that the smooth flow behind it may be associated with low, or at least not increased, drag.

“The sharp leading edge of the bat wing generates the LEV,” Spedding said, “while the bat’s ability to actively change its wing shape and wing curvatures may contribute to control and stability in the leading-edge vortex.”

Spedding and his colleagues believe observations of LEVs in active, unrestricted bat flight have important implications for overall aerodynamic theory and for the design of miniature robotic flight vehicles, which have been undergoing dramatic modifications in recent years.

“There’s much to be learned from bat flight about unsteady flows and forces on small bodies,” Spedding said. “We have suspected for a while that insects weren’t the only creatures affected by highly unsteady viscous air flows, but now we know that larger animals adapted for slow and hovering flight, such as these nectar-feeding bats, can – and perhaps must – use LEVs to enhance flight performance. So, if we wish to build a highly maneuverable, slow-flying surveillance plane, maybe it should flap its wings like a bat?”

The paper in Science is: Leading-Edge Vortex Improves Lift in Slow-Flying Bats, authors are F T Muijres, L C Johansson, R Barfield, M Wolf, G R Spedding and A Hedenström.
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Miniature Auto Differential Helps Tiny Aerial Robots Stay Aloft

Microrobots could be used for search and rescue, agriculture, environmental monitoringEngineers at Harvard University have created a millionth-scale automobile differential to govern the flight of minuscule aerial robots that could someday be used to probe environmental hazards, forest fires, and other places too perilous for people.
Their new approach is the first to passively balance the aerodynamic forces encountered by these miniature flying devices, letting their wings flap asymmetrically in response to gusts of wind, wing damage, and other real-world impediments.
"The drivetrain for an aerial microrobot shares many characteristics with a two-wheel-drive automobile," says lead author Pratheev S. Sreetharan, a graduate student in Harvard's School of Engineering and Applied Sciences. "Both deliver power from a single source to a pair of wheels or wings. But our PARITy differential generates torques up to 10 million times smaller than in a car, is 5 millimeters long, and weighs about one-hundredth of a gram -- a millionth the mass of an automobile differential."
High-performance aerial microrobots, such as those the Harvard scientists describe in the Journal of Mechanical Design, could ultimately be used to investigate areas deemed too dangerous for people. Scientists at institutions including the University of California, Berkeley, University of Delaware, University of Tokyo, and Delft University of Technology in the Netherlands are exploring aerial microrobots as cheap, disposable tools that might someday be deployed in search and rescue operations, agriculture, environmental monitoring, and exploration of hazardous environments.
To fly successfully through unpredictable environments, aerial microrobots -- like insects, nature's nimblest fliers -- have to negotiate conditions that change second-by-second. Insects usually accomplish this by flapping their wings in unison, a process whose kinematic and aerodynamic basis remains poorly understood.
Sreetharan and his co-author, Harvard engineering professor Robert J. Wood, recognized that an aerial microrobot based on an insect need not contain complex electronic feedback loops to precisely control wing position.
"We're not interested so much in the position of the wings as the torque they generate," says Wood, an associate professor of electrical engineering at Harvard. "Our design uses 'mechanical intelligence' to determine the correct wing speed and amplitude to balance the other forces affecting the robot. It can slow down or speed up automatically to correct imbalances."
Sreetharan and Wood found that even when a significant part of an aerial microrobot's wing was removed, the self-correction engendered by their PARITy (Passive Aeromechanical Regulation of Imbalanced Torques) drivetrain allowed the device to remain balanced in flight. Smaller wings simply flapped harder to keep up with the torque generated by an intact wing, reaching speeds of up to 6,600 beats per minute.
The Harvard engineers say their passive approach to regulating the forces generated in flight is preferable to a more active approach involving electronic sensors and computation, which would add weight and complexity to devices intended to remain as small as lightweight as possible. Current-generation aerial microrobots are about the size and weight of many insects, and even make a similar buzzing sound when flying.
"We suspect that similar passive mechanisms exist in nature, in actual insects," Sreetharan says. "We take our inspiration from biology, and from the elegant simplicity that has evolved in so many natural systems."
Sreetharan and Wood's work was funded by the National Science Foundation.

Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Harvard University, via EurekAlert!, a service of AAAS.
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Ants Take on Goliath Role in Protecting Trees in the Savanna from Elephants

Ants are not out of their weight class when defending trees from the appetite of nature's heavyweight, the African elephant, a new University of Florida study finds.
Columns of angered ants will crawl up into elephant trunks to repel the ravenous beasts from devouring tree cover throughout drought-plagued East African savannas, playing a potentially important role in regulating carbon sequestration in these ecosystems, said Todd Palmer, a UF biology professor and co-author of a paper being published in the journal Current Biology.

"It really is a David and Goliath story, where these little ants are up against these huge herbivores, protecting trees and having a major impact on the ecosystems in which they live," Palmer said. "Swarming groups of ants that weigh about 5 milligrams each can and do protect trees from animals that are about a billion times more massive."

The mixture of trees and grasses that make up savanna ecosystems are traditionally thought to be regulated by rainfall, soil nutrients, plant-eating herbivores and fire, he said.

"Our results suggest that plant defense should be added to the list," he said. "These ants play a central role in preventing animals that want to eat trees from doing extensive damage to those trees."

While conducting research in the central highlands of Kenya, where hungry elephants have destroyed much of the tree cover, Palmer said he and his colleague and former UF post-doctoral student, Jacob Goheen, now a University of Wyoming zoology, physiology and botany professor, noticed that elephants rarely ate a widespread tree species known as Acacia drepanolobium where guardian ants aggressively swarm anything that touches the trees. But they would feed on other trees that did not harbor these ants.

The researchers decided to test whether these tiny ants were repelling the world's largest land mammal by serving as bodyguards for the tree in exchange for shelter and the food it supplied in the form of a sugary nectar solution. So they offered elephants at a wildlife orphanage a choice between these "ant plant" trees, with and without ants on the branches, and their favorite species of tree, the Acacia mellifera, to which the researchers added ants to some of its otherwise antless branches.

"We found the elephants like to eat the "ant plant" trees just as much as they like to eat their favorite tree species, and that when either tree species had ants on them, the elephants avoided those trees like a kid avoids broccoli," he Palmer said.

Also, the researchers removed ants from "ant trees" out in the field to see if elephants would attack them undefended, and a year later found much more damage than on trees with ants. Satellite images between 2003 and 2008 confirmed the ants were having a widespread, long-term effect throughout the savanna, he said.

The ants did not seem to annoy tree-feeding giraffes, who used their long tongues to swipe away them away from their short snouts, in marked contrast to the long nose or trunk on an elephant, Palmer said. The inside of an elephant's trunk is tender and highly sensitive to thousands of biting ants swarming up into it, he said.

"An elephant's trunk is a truly remarkable organ, but also appears to be their Achille's heel when it comes to squaring off with an angry ant colony," he said.

Because it appears that smell alerts elephants to avoid trees that are occupied by ants, it raises the question of whether ant odors might be applied to crops to deter elephants from feeding on them, just as DEET helps repel mosquitoes from people, he said.

"A big issue in east Africa is elephants damaging crops, which is one reason elephants have been harassed and sometimes killed," he said. "There's been a lot of interest in the conservation world about how to minimize the conflict elephants have with humans and particularly how to keep elephants from raiding agricultural fields."

One predicted outcome of global warming is more frequent and intense droughts, which will force desperate elephants to eat everything they can to survive, Palmer said "With more droughts, the extent to which elephants destroy and remove trees may increase and potentially shift the ecosystems back to grasslands," he said.

Ants' role in saving trees is critical with the interest in slowing the accumulation of greenhouse gasses since trees absorb carbon dioxide from the atmosphere, Palmer said.

"These 'ant plants' don't cover just a few hundred acres but are distributed throughout east Africa from southern Sudan all the way over to eastern Zaire and down through the horn of Africa and Tanzania," he said. "So they potentially play a big role in terms of regulating carbon dynamics in these ecosystems."
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