Replica Watches

2013-05-17

Weather on the outer planets only goes so deep

May 16, 2013 — What is the long-range weather forecast for the giant planets Uranus and Neptune? These planets are home to extreme winds blowing at speeds of over 1000 km/hour, hurricane-like storms as large around as Earth, immense weather systems that last for years and fast-flowing jet streams. Both planets feature similar climates, despite the fact that Uranus is tipped on its side with the pole facing the sun during winter. The winds on these planets have been observed on their outer surfaces; but to get a grasp of their weather systems, we need to have an idea of what is going on underneath. For instance, do the atmospheric patterns arise from deep down in the planet, or are they confined to shallower processes nearer the surface?

New research at the Weizmann Institute of Science, the University of Arizona and Tel Aviv University, which was published online today in Nature, shows that the wind patterns seen on the surface can extend only so far down on these two worlds.

Understanding the atmospheric circulation is not simple for a planet without a solid surface, where Earth-style boundaries between solid, liquid and gas layers do not exist. Since the discovery of these strong atmospheric winds in the 1980s by the Voyager II spacecraft, the vertical extent of these winds has been a major puzzle -- one that influences our understanding of the physics governing the atmospheric dynamics and internal structure of these planets. But a team led by Dr. Yohai Kaspi of the Weizmann Institute's Environmental Sciences and Energy Research Department realized they had a way, based on a novel method for analyzing the gravitational field of the planets, to determine an upper limit for the thickness of the atmospheric layer.

Deviations in the distribution of mass in planets cause measurable fluctuations in the gravitational field. On Earth, for example, an airplane flying near a large mountain feels the slight extra gravitational pull of that mountain. Like Earth, the giant planets of the solar system are rapidly rotating bodies. In fact all of them rotate faster than Earth; the rotation periods of Uranus and Neptune are about 17 and 16 hours, respectively. Because of this rapid rotation, the winds swirl around regions of high and low pressure. (In a non-rotating body, flow would be from high to low pressure.) This enables researchers to deduce the relations between the distribution of pressure and density, and the planets' wind field. These physical principles enabled Kaspi and his co-authors to calculate, for the first time, the gravity signature of the wind patterns and thus create a wind-induced gravity map of these planets.

By computing the gravitational fields of a large range of ideal planet models -- ones with no wind, a task conducted by team member Dr. Ravit Helled of Tel Aviv University -- and comparing them with the observed gravitational fields, upper limits to the meteorological contribution to the gravitational fields were obtained. This enabled Kaspi's team, which included Profs. Adam Showman and Bill Hubbard of the University of Arizona, and Prof. Oded Aharonson of the Weizmann Institute, to show that the streams of gas observed in the atmosphere are limited to a "weather-layer" of no more than about 1000 km in depth, which makes up only a fraction of a percent of the mass of these planets.

Although no spacecraft missions to Uranus and Neptune are planned for the near future, Kaspi anticipates that the team's findings will be useful in the analysis of another set of atmospheric circulation patterns that will be closely observed soon: those of Jupiter. Kaspi, Helled and Hubbard are part of the science team of NASA's Juno spacecraft to Jupiter. Juno was launched in 2011; upon reaching Jupiter in 2016 it will provide very accurate measurements of the gravity field of this giant gaseous planet. Using the same methods as the present study, Kaspi anticipates that they will be able to obtain the same type of information they acquired for Uranus and Neptune: namely, placing constraints on the depth of the atmospheric dynamics of this planet.

Uranus and Neptune are the farthest planets in the solar system, and there are still many open questions regarding their formation and composition. This study has implications for revealing the mysteries of their deep, dark interiors, and may even provide information about how these planets were formed. Moreover, many of the extrasolar planets detected around other stars have been found to have similar masses to those of Uranus and Neptune, so this research will be important for understanding like-sized extrasolar planets, as well.

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Engineers monitor heart health using paper-thin flexible 'skin'

May 16, 2013 — Most of us don't ponder our pulses outside of the gym. But doctors use the human pulse as a diagnostic tool to monitor heart health.

Zhenan Bao, a professor of chemical engineering at Stanford, has developed a heart monitor thinner than a dollar bill and no wider than a postage stamp. The flexible skin-like monitor, worn under an adhesive bandage on the wrist, is sensitive enough to help doctors detect stiff arteries and cardiovascular problems.

The devices could one day be used to continuously track heart health and provide doctors a safer method of measuring a key vital sign for newborn and other high-risk surgery patients.

"The pulse is related to the condition of the artery and the condition of the heart," said Bao, whose lab develops artificial skin-like materials. "The better the sensor, the better doctors can catch problems before they develop."

Your pulse

To find your pulse, press your index and middle finger into the underside of your opposite wrist. You should feel the steady rhythm of your heart as it pumps blood through your veins.

Each beat you feel is actually made up of two distinct peaks, even though you can't tell them apart with just your fingers. The first, larger peak is from your heart pumping out blood. Shortly after a heartbeat, your lower body sends a reflecting wave back to your artery system, creating a smaller second peak.

The relative sizes of these two peaks can be used by medical experts to measure your heart's health.

"You can use the ratio of the two peaks to determine the stiffness of the artery, for example," said Gregor Schwartz, a post-doctoral fellow and a physicist for the project. "If there is a change in the heart's condition, the wave pattern will change. Fortunately, when I tested this on myself, my heart looked fine."

To make the heart monitor both sensitive and small, Bao's team uses a thin middle layer of rubber covered with tiny pyramid bumps. Each mold-made pyramid is only a few microns across -- smaller than a human red blood cell.

When pressure is put on the device, the pyramids deform slightly, changing the size of the gap between the two halves of the device. This change in separation causes a measurable change in the electromagnetic field and the current flow in the device.

The more pressure placed on the monitor, the more the pyramids deform and the larger the change in the electromagnetic field. Using many of these sensors on a prosthetic limb could act like an electronic skin, creating an artificial sense of touch.

When the sensor is placed on someone's wrist using an adhesive bandage, the sensor can measure that person's pulse wave as it reverberates through the body.

The device is so sensitive that it can detect more than just the two peaks of a pulse wave. When engineers looked at the wave drawn by their device, they noticed small bumps in the tail of the pulse wave invisible to conventional sensors. Bao said she believes these fluctuations could potentially be used for more detailed diagnostics in the future.

Blood pressure and babies

Doctors already use similar, albeit much bulkier, sensors to keep track of a patient's heart health during surgery or when taking a new medication. But in the future Bao's device could help keep track of another vital sign.

"In theory, this kind of sensor can be used to measure blood pressure," said Schwartz. "Once you have it calibrated, you can use the signal of your pulse to calculate your blood pressure."

This non-invasive method of monitoring heart health could replace devices inserted directly into an artery, called intravascular catheters. These catheters create a high risk of infection, making them impractical for newborns and high-risk patients. Thus, an external monitor like Bao's could provide doctors a safer way to gather information about the heart, especially during infant surgeries.

Bao's team is working with other Stanford researchers to make the device completely wireless. Using wireless communication, doctors could receive a patient's minute-by-minute heart status via cell phone, all thanks to a device as thick as a human hair.

"For some patients with a potential heart disease, wearing a bandage would allow them to constantly measure their heart's condition," Bao said. "This could be done without interfering with their daily life at all, since it really just requires wearing a small bandage."

The team published its work in the May 12 edition of Nature Communications. The team's research is supported by funding from the National Science Foundation and the Air Force Office of Scientific Research.

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Stem-cell-based strategy boosts immune system in mice

The scientists who developed the thymus cells -- which caused the proliferation and maturation of functioning immune cells when transplanted -- said the achievement marks a significant step toward potential new treatments based on stem-cell and organ transplantation, as well as new therapies for type-1 diabetes and other autoimmune diseases, and for immunodeficiency diseases.

Starting with human embryonic stem cells, UCSF researchers led by Mark Anderson, MD, PhD, an immunologist, and Matthias Hebrok, PhD, a stem-cell researcher and the director of the UCSF Diabetes Center, used a unique combination of growth factors to shape the developmental trajectory of the cells, and eventually hit upon a formula that yielded functional thymus tissue.

The result, reported in the May 16, 2013 online edition of the journal Cell Stem Cell, is functioning tissue that nurtures the growth and development of the white blood cells known as T cells. T cells are a central immune cell population that responds to specific disease pathogens and also prevents the immune system from attacking the body's own tissues.

The thymus might be a bit obscure to the layperson -- it's a small gland at the top of the chest beneath the breastbone -- but it is in no way expendable, as individuals with defective thymus function succumb to infection early in life.

Given the invasive nature of cell therapy, which remains completely experimental, the first treatments using laboratory-derived thymus tissue would likely be studied in patients with fatal diseases for which there are no effective treatments, Anderson said. For example, one early treatment might be for the genetic disease DeGeorge syndrome, in which some newborns are born without a thymus gland and die in infancy.

However, a potentially greater impact may be in the area of tissue transplantation, a goal of the emerging field of stem-cell based therapies. Stem-cell-based therapies now are limited by the potential for the immune system to reject transplanted stem cells, Anderson said. For transplantation, stem cells might be coaxed down two developmental pathways simultaneously, to form both thymus tissue and a replacement organ. Transplantation of both might overcome the rejection barrier without the need for harmful immunosuppression, according to Anderson.

"The thymus is an environment in which T cells mature, and where they also are instructed on the difference between self and non-self," Anderson said. Some T cells are prepared by the thymus to attack foreign invaders -- including transplants, while T cells that would attack our own tissues normally are eliminated in the thymus.

In the same vein, thymus tissue might one day be used to retrain the immune system in autoimmune diseases in which the immune system abnormally attacks "self," thereby enhancing recognition and protecting from immune destruction.

Researchers have discovered many of the proteins and growth factors that are switched on during the course of embryonic development and that are crucial to organ formation. Hebrok has spent years trying to develop insulin-secreting beta cells, a part of the pancreas that is destroyed during the course of diabetes.

The sequential appearance of specific marker proteins within cells as they develop into the distinct organs of the gastrointestinal tract serves as a series of milestones, which has helped orient Hebrok and others as they seek to guide the formation of distinct tissues.

Hebrok likens the quest for organ specific cells, including thymus cells and the elusive pancreatic beta cell, to an adventurous road trip. The pancreas and the thymus branch off the gastrointestinal tract in different places, but they share certain developmental markers.

To get to thymus cells, the researchers tried dozens of protocols, timing the switching on of the key factors differently each time. "If we used one factor for a day longer or shorter it would not work," Hebrok said. With the milestones misplaced, "It would be like driving down the highway and missing your exit."

The researchers caution that they have not perfectly replicated the thymus, and that only about 15 percent of cells are successfully directed to become thymus tissue with the protocol used in the study.

Even so, Anderson said, "We now have developed a tool that allows us to modulate the immune system in a manner that we never had before."

Additional study authors include UCSF Diabetes Center postdoctoral fellows Audrey Parent, PhD, Holger Russ, PhD; and graduate students Imran Khan, Taylor LaFlam, and Todd Metzger.

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Ten percent of notebooks using touch screens

SAN JOSE, Calif. – Notebooks are tapping 10-inch and larger capacitive touch screen displays at a rapid and expanding pace, despite the market difficulties of Microsoft’s Windows 8, said one market watcher.

In the first quarter of 2013, 4.57 million notebooks shipped with capacitive touch screens, up 51.8 percent from the previous quarter. That’s about ten percent of the total 46 million notebooks sold in the period, said Displaybank, a division of IHS

“Touch-screen notebooks should hold at least 10 percent of the total laptop shipments,” the company said in a new report on the sector. “In particular, brands from the greater China region, including Lenovo, Acer and Asus, have set higher targets of achieving more than 20 percent [adoption],” the report said.

Click on image to enlarge.Displaybanks says 11.6-inchers command the sweet spot.

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Fast and painless way to better mental arithmetic? Yes, there might actually be a way

May 16, 2013 — In the future, if you want to improve your ability to manipulate numbers in your head, you might just plug yourself in. So say researchers who report in the Cell Press journal Current Biology on May 16 on studies of a harmless form of brain stimulation applied to an area known to be important for math ability.

"With just five days of cognitive training and noninvasive, painless brain stimulation, we were able to bring about long-lasting improvements in cognitive and brain functions," says Roi Cohen Kadosh of the University of Oxford.

Incredibly, the improvements held for a period of six months after training. No one knows exactly how this relatively new method of stimulation, called transcranial random noise stimulation (TRNS), works. But the researchers say the evidence suggests that it allows the brain to work more efficiently by making neurons fire more synchronously.

Cohen Kadosh and his colleagues had shown previously that another form of brain stimulation could make people better at learning and processing new numbers. But, he says, TRNS is even less perceptible to those receiving it. TRNS also has the potential to help even more people. That's because it has been shown to improve mental arithmetic -- the ability to add, subtract, or multiply a string of numbers in your head, for example -- not just new number learning. Mental arithmetic is a more complex and challenging task, which more than 20 percent of people struggle with.

Ultimately, Cohen Kadosh says, with better integration of neuroscience and education, this line of study could really help humans reach our cognitive potential in math and beyond. It might also be of particular help to those suffering with neurodegenerative illness, stroke, or learning difficulties.

"Maths is a highly complex cognitive faculty that is based on a myriad of different abilities," Cohen Kadosh says. "If we can enhance mathematics, therefore, there is a good chance that we will be able to enhance simpler cognitive functions."

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Invasive crazy ants are displacing fire ants in areas throughout southeastern US

The "ecologically dominant" crazy ants are reducing diversity and abundance across a range of ant and arthropod species -- but their spread can be limited if people are careful not to transport them inadvertently, according to Ed LeBrun, a research associate with the Texas invasive species research program at the Brackenridge Field Laboratory in the College of Natural Sciences

The study by LeBrun and his colleagues was published in Biological Invasions.

"When you talk to folks who live in the invaded areas, they tell you they want their fire ants back," said LeBrun. "Fire ants are in many ways very polite. They live in your yard. They form mounds and stay there, and they only interact with you if you step on their mound."

LeBrun said that crazy ants, by contrast, "go everywhere." They invade people's homes, nest in crawl spaces and walls, become incredibly abundant and damage electrical equipment.

The crazy ants were first discovered in the U.S. in 2002 by a pest control operator in a suburb of Houston, and have since established populations in 21 counties in Texas, 20 counties in Florida, and a few sites in southern Mississippi and southern Louisiana.

In 2012 the species was formally identified as Nylanderia fulva, which is native to northern Argentina and southern Brazil. Frequently referred to as Rasberry crazy ants, these ants recently have been given the official common name "Tawny crazy ants."

The Tawny crazy ant invasion is the most recent in a series of ant invasions from South America brought on by human movement. The Argentine ant invaded through the port of New Orleans in about 1891. In 1918 the black imported fire ant showed up in Mobile, Ala. Then in the 1930s, the red imported fire ant arrived in the U.S. and began displacing the black fire ant and the Argentine ants.

The UT researchers studied two crazy ant invasion sites on the Texas Gulf Coast and found that in those areas where the Tawny crazy ant population is densest, fire ants were eliminated. Even in regions where the crazy ant population is less dense, fire ant populations were drastically reduced. Other ant species, particularly native species, were also eliminated or diminished.

LeBrun said crazy ants are much harder to control than fire ants. They don't consume most of the poison baits that kill fire ant mounds, and they don't have the same kinds of colony boundaries that fire ants do. That means that even if they're killed in a certain area, the supercolony survives and can swarm back over the area.

"They don't sting like fire ants do, but aside from that they are much bigger pests," he said. "There are videos on YouTube of people sweeping out dustpans full of these ants from their bathroom. You have to call pest control operators every three or four months just to keep the infestation under control. It's very expensive."

LeBrun said that in northern Argentina and southern Brazil, where the ants are native, populations are likely held in check by other ant species and a variety of natural enemies. In the U.S. there is no such natural control.

Here the crazy ants can attain densities up to 100 times as great as all other ants in the area combined. In the process, they monopolize food sources and starve out other species. LeBrun said the crazy ants, which are omnivorous, may also directly attack and kill other ant and arthropod species.

The overall result is a significant reduction in abundance and biodiversity at the base of the food chain, which is likely to have implications for the ecosystem as a whole.

"Perhaps the biggest deal is the displacement of the fire ant, which is the 300 pound gorilla in Texas ecosystems these days," said LeBrun. "The whole system has changed around fire ants. Things that can't tolerate fire ants are gone. Many that can have flourished. New things have come in. Now we are going to go through and whack the fire ants and put something in its place that has a very different biology. There are going to be a lot of changes that come from that."

LeBrun said a great deal about the Tawny crazy ants remains unknown, including their potential range. So far, most of the colonies are in fairly wet environments with mild winters, near the coast, so it may be the case that they can't thrive in drier or colder climates, and that fire ants will remain dominant in those areas.

The spread of the Tawny crazy ants may also be limited, even within the more hospitable climates, by caution from humans. The reproductive members of the species don't fly. So when left to their own devices, crazy ant colonies can only advance about 200 meters a year. That means they're dependent on humans to colonize new areas.

"They are opportunistic nesters," said LeBrun. "They can take up residence in everything from a house plant, to an empty container left outside, to an RV. So they're easily transported by us. But the flip side of that is that if people living in or visiting invaded areas are careful and check for the crazy ants when moving or going on longer trips, they could have a huge impact on the spread." Nursery products also appear to be a key way these ants spread, so both buyers and sellers should be watchful for these ants.

LeBrun said that cutting down on the number of transplantation events could slow the spread by years or decades. And that extra time could give the ecosystem time to adapt and researchers time to develop better control methods.

"We can really make a difference," he said, "but we need to be careful, and we need to know more."

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Taiwan funds smartphone innovations

TAIPEI--Taiwan's innovators have taken to heart what Steve Jobs said during the introduction of the iPad 2 in 2011: "It is technology married with liberal arts, married with the humanities, that yields us the result that makes our heart sing and nowhere is that more true than in these post-PC devices."

National Taiwan University (NTU) has implemented that mantra in recent innovations for tablets and smartphones designed to win the hearts of mass-market users. Earlier this month, NTU won the best paper award at the ACM's Conference on Human Factors in Computing Systems (CHI) in Paris. The first-prize award—among hundreds of entries—was for NTU's NailDisplay, an LCD in the shape of the thumbnail.

Once attached—like an artificial fingernail—the display shows a photo of a real thumbnail so it becomes almost invisible to the naked eye. However, as soon as your smartphone rings in your pocket, it displays who is calling so you do not have to dig your phone out of your pocket unless you want to answer.

"Since a thumbnail is relatively wide and flat, it can easily accommodate a touchscreen that allows the user to control their mobile phone," said computer science and information engineering (CSIE) student Rong-Hao Liang, who presented the paper at CHI 2013 for NTU's communications and multimedia lab.

NTU's magnetic field detector add-on, the GaussSense magnetic sensor grid, can be built into an iPad case, solving the finger-occlusion problem by allowing near-field sensing of magnetic styluses and GaussBit tokens without interference from users hands.

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DNA-guided assembly yields novel ribbon-like nanostructures

The research, described in a paper published online in ACS Nano, a journal of the American Chemical Society, could result in the fabrication of new nanostructured materials with desired properties.

"This is a completely new mechanism of self-assembly that does not have direct analogs in the realm of molecular or microscale systems," said Brookhaven physicist Oleg Gang, lead author on the paper, who conducted the bulk of the research at the Lab's Center for Functional Nanomaterials.

Broad classes of rod-like objects, ranging from molecules to viruses, often exhibit typical liquid-crystal-like behavior, where the rods align with a directional dependence, sometimes with the aligned crystals forming two-dimensional planes over a given area. Rod shaped objects with strong directionality and attractive forces between their ends-resulting, for example, from polarized charge distribution-may also sometimes line up end-to-end forming linear one-dimensional chains.

Neither typical arrangement is found in the DNA-tethered nanorods.

"Our discovery shows that a qualitatively new regime emerges for nanoscale objects decorated with flexible molecular tethers of comparable sizes-a one-dimensional ladder-like linear arrangement that appears in the absence of end-to-end affinity among the rods," Gang said.

Alexei Tkachenko, the CFN scientist who developed the theory to explain the exceptional arrangement, elaborated: "Remarkably, the system has all three dimensions to live in, yet it chooses to form the linear, almost one-dimensional ribbons. It can be compared to how extra dimensions that are hypothesized by high-energy physicists become 'hidden,' so that we find ourselves in a 3-D world."

Tkachenko explains how the ladder-like alignment results from a fundamental symmetry breaking:

"Once a nanorod connects to another one side-by-side, it loses the cylindrical symmetry it had when it had free tethers all around. Then, the next nanorod will preferentially bind to another side of the first, where there are still DNA linkers available."

DNA as glue

Using synthetic DNA as a form of molecular glue to guide nanoparticle assembly has been a central approach of Gang's research at the CFN. His previous work has shown that strands of this molecule-better known for carrying the genetic code of living things-can pull nanoparticles together when strands bearing complementary sequences of nucleotide bases (known by the letters A, T, G, and C) are used as tethers, or inhibit binding when unmatched strands are used. Carefully controlling those attractive and inhibitory forces can lead to fine-tuned nanoscale engineering.

In the current study, the scientists used gold nanorods and single strands of DNA to explore arrangements made with complementary tethers attached to adjacent rods. They also examined the effects of using linker strands of varying lengths to serve as the tethering glue.

After mixing the various combinations, they studied the resulting arrangements using ultraviolet-visible spectroscopy at the CFN, and also with small-angle x-ray scattering at Brookhaven's National Synchrotron Light Source (NSLS, http://www.bnl.gov/ps/nsls/about-NSLS.asp). They also used techniques to "freeze" the action at various points during assembly and observed those static phases using scanning electron microscopy to get a better understanding of how the process progressed over time.

The various analysis methods confirmed the side-by-side arrangement of the nanorods arrayed like rungs on a ladder-like ribbon during the early stages of assembly, followed later by stacking of the ribbons and finally larger-scale three-dimensional aggregation due to the formation of DNA bridges between the ribbons.

This staged assembly process, called hierarchical, is reminiscent of self-assembly in many biological systems (for example, the linking of amino acids into chains followed by the subsequent folding of these chains to form functional proteins).

The stepwise nature of the assembly suggested to the team that the process could be stopped at the intermediate stages. Using "blocker" strands of DNA to bind up the remaining free tethers on the linear ribbon-like structures, they demonstrated their ability to prevent the later-stage interactions that form aggregate structures.

"Stopping the assembly process at the ladder-like ribbon stage could potentially be applied for the fabrication of linear structures with engineered properties," Gang said. "For example by controlling plasmonic or fluorescent properties-the materials' responses to light-we might be able to make nanoscale light concentrators or light guides, and be able to switch them on demand."

Additional authors on this study include: Stephanie Vial of CFN and the International Iberian Nanotechnology Laboratory in Braga, Portugal, and Dmytro Nykypanchuk, and Kevin Yager, all of CFN.

This research was funded by the DOE Office of Science (BES), which also provides operations support for the CFN and NSLS at Brookhaven Lab.

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New insights into how materials transfer heat could lead to improved electronics

May 16, 2013 — U of T Engineering researchers, working with colleagues from Carnegie Mellon University, have published new insights into how materials transfer heat, which could lead eventually to smaller, more powerful electronic devices.

Integrated circuits and other electronic parts have been shrinking in size and growing in complexity and power for decades. But as circuits get smaller, it becomes more difficult to dissipate waste heat. For further advances to be made in electronics, researchers and industry need to find ways of tracking heat transfer in products ranging from smart phones to computers to solar cells.

Dan Sellan and Professor Cristina Amon, of U of T's Mechanical and Industrial Engineering department, investigated a new tool to measure the thermal and vibrational properties of solids. Working with colleagues from Carnegie Mellon University, they studied materials in which heat is transferred by atomic vibrations in packets called phonons. Their results were recently published in Nature Communications.

"In an analogy to light, phonons come in a spectrum of colors, and we have developed a new tool to measure how different color phonons contribute to the thermal conductivity of solids," said Jonathan Malen, an assistant professor of Mechanical Engineering at CMU.

According to the researchers, the new tool will give both industry and academia a clearer picture of how an electronic device's ability to dissipate heat shrinks with its size, and how materials can be structured at the nanoscale to change their thermal conductivity.

For example, in the initial demonstration, the team showed that as silicon microprocessors continue to shrink, their operating temperatures will be further challenged by reduced thermal conductivity.

"Our modeling work provides an in-depth look at how individual phonons impact thermal conductivity," said Sellan, who undertook his research as a PhD Candidate in Professor Amon's lab. Currently an NSERC Postdoctoral Fellow at The University of Texas at Austin, Sellan is developing experimental techniques for thermal measurements.

Professor Amon, who is also Dean of the Faculty of Applied Science & Engineering at U of T, said Sellan's insights will allow researchers to design nanostructured thermoelectric materials with increased efficiency in converting waste heat to electrical energy. This work has exciting implications for the future of nano-scale thermal conductivity research."

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2013-05-16

徽派玉雕拟申报非物质文化遗产

　　徽派三雕“木雕、石雕、砖雕”全国闻名,而昨日记者从徽派玉雕文化协会成立大会上了解到,徽派玉雕也拟申请省非物质文化遗产.

　　徽派玉雕起源于安徽凌家滩文化,凌家滩文化遗址大墓内随葬品以高规格玉器为主.据了解,徽派玉雕雏形形成于宋代,风格玲珑精细,善用光影,以线塑形.协会负责人表示,在全国各主要玉雕创作基地,60%的玉雕匠人和大师皆为安徽籍,所以在省文化厅和民政厅支持下,徽派玉雕文化协会昨日得以成立.目前协会正在筹备为徽派玉雕申请非物质文化遗产,做强徽派玉雕.(蒋楠楠)

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No idle chatter: Malaria parasites 'talk' to each other

The finding could provide a niche for developing antimalarial drugs and vaccines that prevent or treat the disease by cutting these communication networks.

Professor Alan Cowman, Dr Neta Regev-Rudzki, Dr Danny Wilson and colleagues from the Walter and Eliza Hall Institute's Infection and Immunity division, in collaboration with Professor Andrew Hill from the University of Melbourne's Bio21 Institute and Department of Biochemistry and Molecular Biology showed that malaria parasites are able to send out messages to communicate with other malaria parasites in the body. The study was published today in the journal Cell.

Professor Cowman said the researchers were shocked to discover that malaria parasites work in unison to enhance 'activation' into sexually mature forms that can be picked up by mosquitoes, which are the carriers of this deadly disease.

"When Neta showed me the data, I was absolutely amazed, I couldn't believe it," Professor Cowman said. "We repeated the experiments many times in many different ways before I really started to believe that these parasites were signalling to each other and communicating. But we came to appreciate why the malaria parasite really needs this mechanism -- it needs to know how many other parasites are in the human to sense when is the right time to activate into sexual forms that give it the best chance of being transmitted back to the mosquito."

Malaria kills about 700,000 people a year, mostly children aged under five and pregnant women. Every year, hundreds of millions of people are infected with the malaria parasite, Plasmodium, which is transmitted through mosquito bites. It is estimated that half the world's population is at risk of contracting malaria, with the disease being concentrated in tropical and subtropical regions including many of Australia's near neighbours.

Dr Regev-Rudzki said the malaria parasites inside red blood cells communicate by sending packages of DNA to each other during the blood stage of infection. "We showed that the parasites inside infected red blood cells can send little packets of information from one parasite to another, particularly in response to stress," she said.

The communication network is a social behaviour that has evolved to signal when the parasites should complete their lifecycle and be transmitted back to a mosquito, Dr Regev-Rudzki said. "Once they receive this information, they change their fate -- the signals tell the parasites to become sexual forms, which are the forms of the malaria parasite that can live and replicate in the mosquito, ensuring the parasites survives and is transmitted to another human."

Professor Cowman said he hopes to see the discovery pave the way to new antimalarial drugs or vaccines for preventing malaria. "This discovery has fundamentally changed our view of the malaria parasite and is a big step in understanding how the malaria parasite survives and is transmitted," he said. "The next step is to identify the molecules involved in this signalling process, and ways that we could block these communication networks to block the transmission of malaria from the human to the mosquito. That would be the ultimate goal."

This project was supported by the National Health and Medical Research Council of Australia, Howard Hughes Medical Institute and the Victorian Government.

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