星空健康频道

2013年7月6日星期六

Researcher sheds light on M.O. of unusual RNA molecules

Now a team of researchers led by newly arrived biologist Mitchell Guttman of the California Institute of Technology (Caltech) and Kathrin Plath of UCLA, has figured out how some RNA molecules take advantage of their position within the three-dimensional mishmash of genomic material to home in on targets. The research appears in the current issue of Science Express.

The findings suggests a unique role for a class of RNAs, called lncRNAs, which Guttman and his colleagues at the Broad Institute of MIT and Harvard first characterized in 2009. Until then, these lncRNAs -- short for long, noncoding RNAs and pronounced "link RNAs" -- had been largely overlooked because they lie in between the genes that code for proteins. Guttman and others have since shown that lncRNAs scaffold, or bring together and organize, key proteins involved in the packaging of genetic information to regulate gene expression -- controlling cell fate in some stem cells, for example.

In the new work, the researchers found that lncRNAs can easily locate and bind to nearby genes. Then, with the help of proteins that reorganize genetic material, the molecules can pull in additional related genes and move to new sites, building up a "compartment" where many genes can be regulated all at once.

"You can now think about these lncRNAs as a way to bring together genes that are needed for common function into a single physical region and then regulate them as a set, rather than individually," Guttman says. "They are not just scaffolds of proteins but actual organizers of genes."

The new work focused on Xist, a lncRNA molecule that has long been known to be involved in turning off one of the two X chromosomes in female mammals (something that must happen in order for the genome to function properly). Quite a bit has been uncovered about how Xist achieves this silencing act. We know, for example, that it binds to the X chromosome; that it recruits a chromatin regulator to help it organize and modify the structure of the chromatin; and that certain distinct regions of the RNA are necessary to do all of this work. Despite this knowledge, it had been unknown at the molecular level how Xist actually finds its targets and spreads across the X chromosome.

To gain insight into that process, Guttman and his colleagues at the Broad Institute developed a method called RNA Antisense Purification (RAP) that, by sequencing DNA at high resolution, gave them a way to map out exactly where different lncRNAs go. Then, working with Plath's group at UCLA, they used their method to watch in high resolution as Xist was activated in undifferentiated mouse stem cells, and the process of X-chromosome silencing proceeded.

"That's where this got really surprising," Guttman says. "It wasn't that somehow this RNA just went everywhere, searching for its target. There was some method to its madness. It was clear that this RNA actually used its positional information to find things that were very far away from it in genome space, but all of those genes that it went to were really close to it in three-dimensional space."

Before Xist is activated, X-chromosome genes are all spread out. But, the researchers found, once Xist is turned on, it quickly pulls in genes, forming a cloud. "And it's not just that the expression levels of Xist get higher and higher," Guttman says. "It's that Xist brings in all of these related genes into a physical nuclear structure. All of these genes then occupy a single territory."

The researchers found that a specific region of Xist, known as the A-repeat domain, that is known to be vital for the lncRNA's ability to silence X-chromosome genes is also needed to pull in all the genes that it needs to silence. When the researchers deleted the domain, the X chromosome did not become inactivated, because the silencing compartment did not form.

One of the most exciting aspects of the new research, Guttman says, is that it has implications beyond just explaining how Xist works. "In our paper, we talk a lot about Xist, but these results are likely to be general to other lncRNAs," he says. He adds that the work provides one of the first direct pieces of evidence to explain what makes lncRNAs special. "LncRNAs, unlike proteins, really can use their genomic information -- their context, their location -- to act, to bring together targets," he says. "That makes them quite unique."

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

We have built up long term business relationship with about many companies which are stockers and authorized agents. we have a steady and reliable supply to meet customer's demands to the greatest extent .Confidently, we are able to lower your cost and support your business with our years of professional service.

SUV System Ltd is Electronic Components Distributor Supplies,Find Quality Electronic Components Supplies Products IC(Integrated Circuits),Connectors,Capacitor,Resistors,Diodes,Transistors,LED at Suvsystem.com. Sourcing Other Energy, Environment, Excess Inventory Products from Manufacturers and Suppliers at Suvsystem.com

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

SUV System Ltd insists on the managing faith ofsincereness,speciality,foresight, win-win,so we build up stable-relationship customers located all over the world, including the States, Europe, Argentina, UAE, Malaysia, Australia,and India etc

we are focus on the following fields,and hope we can help you.

AVX High Precision Chip Fuses Current Sensors VISHAY Renesas parts PANASONIC Schottky Freescale Semiconductor DIODES IR transistor MOTOROLA chip Filter saws PANASONIC TOSHIBA Diodes Inc Vishay resistors NXP Metal Can Packages Ligitek LED Voltage Regulators INFLNEON About US IR Fairchild Semiconductor NEC News Thin Film Other Parts Fast Recovery ON Zener MAXIM Transistors Freescale Resistor Arrays Microchip IC Thick Film TI IC HARRIS TDK
http://www.suvsystem.com/a/3522.aspx

Search for Extraterrestrial Intelligence research network launched

The network's Patron is the Astronomer Royal, Professor Martin Rees. UKSRN will present current activity and consider future strategy in a session and panel discussion at the National Astronomy Meeting in St Andrews on Friday 5 July.

UKSRN covers a broad spectrum of research topics, including potential methods for detecting signals, the linguistic challenge of deciphering messages, the probability of an extraterrestrial civilization interacting with Earth and the longevity of civilizations.

Dr Alan Penny, the coordinator of UKSRN said, "We hope that the existence of the network will excite interest from people in the UK astronomical community that have been thinking about SETI and encourage them to contribute their work. In this session at NAM, we are presenting the whole range of UK SETI activities to the community and hope that it will promote a wider understanding of, and activity in, this subject."

Dr Tim O'Brien from The University of Manchester's Jodrell Bank Observatory will describe the capability of the UK's recently commissioned e-MERLIN array of seven radio telescopes for SETI projects and report on progress in initial test observations.

"The first proposal to search for radio signals from extraterrestrial civilisations was actually inspired by the construction of the Lovell Telescope at Jodrell Bank," said O'Brien. "We went on to take part in the SETI Institute's Project Phoenix from 1998 to 2003, searching for signals from about a thousand nearby stars. At that time the equipment required to sift through the data was expensive and unusual, but our modern telescopes are potentially capable of conducting these type of observations as a matter of course."

The e-MERLIN array, which includes the Lovell Telescope, is connected by optical fibres and spread over 217 km from Jodrell Bank to Cambridge. This multi-telescope approach offers potential for distinguishing true extraterrestrial signals from interference generated here on Earth, a key problem for all radio SETI projects.

O'Brien is excited about future prospects, "It's early days for this new SETI work at Jodrell but we think that using e-MERLIN, and future facilities such as the Square Kilometre Array, we could make an important contribution to the search for intelligent life elsewhere in the Universe."

Dr John Elliott of Leeds Metropolitan University is a researcher on the nature of communication: how language structure can be identified, and methods for subsequent decipherment and dissemination. He has analysed over 60 human languages, which cover all the different types of systems, as well as non-human communication, such as robots and dolphins. Elliott believes that by understanding our analytical capabilities for communication, we can develop strategies for extra-terrestrial message discovery and understanding.

"Suppose SETI succeeds and we detect a technological beacon. Any message is unlikely to be written in Martian English, so standard decipherment/decryption techniques used by the military and security agencies are not going to help much. To put the challenge into context, we still have scripts from antiquity that have remained undeciphered over hundreds of years, despite many serious attempts," said Elliott.

Elliott's research focuses on whether there is something unique to communication phenomena, irrespective of the source, that makes them distinguishable from other signals in the universe. "By looking beneath the surface veneer of the arbitrary sounds and symbols used, we can 'see' the language machine itself: its mechanisms, constraints, and evolutionary forces of efficiency and compromise that shape it. By understanding these structures, it should be possible to glean information on the intelligence of the message author," said Elliott.

Back in 1950 during a conversation on SETI, the physicist, Enrico Fermi, posed the question 'Where is everybody?' The paradox between the high estimates for the probability of the existence of extraterrestrial civilizations and the lack of contact or evidence remains a key area of SETI research. Dr Anders Sandberg, of the Future of Humanity Institute at Oxford University, is investigating the question of how far away in space and time a civilization could start and still have a chance of interacting with Earth today.

"If this were a very limited range, the Fermi question, "Where are they?" would be easy to answer: they couldn't have got here yet. However, we show in our paper that, beyond a certain technological level, civilizations can spread not just across their own galaxy but across enormous intergalactic distances. This is mostly limited by how fast their devices are and the expansion of the universe. There are millions or billions of galaxies from which a civilization could have reached us, if it were established early," said Sandberg.

Sandberg and his colleagues have concluded that the answer to the Fermi question is more extreme than normally thought. "If life or intelligence is rare, it must be millions or billions of times rarer; if advanced societies wipe themselves out, or decide to not go exploring, they need to converge to this outcome with extremely high probability, since it only takes one that escapes this fate to fill the universe," said Sandberg.

The work of Dr Austin Gerig, senior research fellow in Complex Networks at the University of Oxford, estimates the fraction of civilizations in the universe that are long-lived and analyses the human race's prospects for survival.

Dr Gerig said, "We know that (1) we exist and that (2) our birth number within our civilization is approximately 70 billion (i.e., approximately 70 billion people were born before us). From such little information, we can reasonably, and perhaps surprisingly, conclude that (1) many other civilizations exist and that (2) most of these civilizations are small, i.e., most will die out before producing trillions of people."

Gerig and his colleagues have focused on a specific consequence of this reasoning, called the "universal doomsday argument": long-lived civilizations must be rare because if they were not, we would find ourselves living in one.

"If most civilizations are small, then our own civilization is likely to be small, i.e., it is likely to die out within the next few centuries. Our research indicates this is the case, but that our estimates of survival are greater than previously thought using a more traditional form of the doomsday argument," said Gerig.

Duncan Forgan, from the Royal Observatory Edinburgh, is looking at the possibility of detecting large structures built by civilizations orbiting other stars. The transit method of detecting extrasolar planets involves measuring the dip in starlight as a planet passes in front of its star. The Kepler Space Telescope has detected a whole host of new exoplanets using the transit technique, and there are many future telescopes and missions lined up to succeed it. Forgan has investigated whether the obstruction of the stellar disc by a large orbiting structure would make a detectable difference in the shape of the lightcurve of an exoplanet transit.

"I looked at one type of megastructure, which is essentially a very large mirror. The mirror reflects the star's own radiation and produces thrust, much like a sail produces thrust from wind. This thrust could be used to move a civilization's host star from its "natural" orbit if it posed some harm to the civilization, for example a dangerous close approach to another star or dust cloud," said Forgan.

Forgan's study showed that a giant mirror of this type would leave a characteristic trace in exoplanet transit data, which could be detectable with the next generation of telescopes.

"While the odds of seeing megastructures are probably very low, we will soon have a huge archive of exoplanet data to search for these objects -- at no extra cost to SETI scientists. We may detect the presence, or remains, of an alien civilization that felt the need to move their star!" said Forgan.

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

we are focus on the following fields,and hope we can help you.

ON About US Current Sensors Xilinx NEC LINEAR AD TI IC PANASONIC MURATA Multi-units News TOSHIBA components Voltage Regulators Bipolar Military IC INFLNEON Other Parts chip Filter saws Switches BB HARRIS Zener ON Renesas parts Freescale Semiconductor Civil IC Vishay resistors Switching Diodes Inc YAGEO Texas Instruments(TI) NS IC ROHM Capacitor IR transistor PANASONIC NEC Fast Recovery
http://www.suvsystem.com/a/3505.aspx

2013年7月5日星期五

Ancient jigsaw puzzle of past supercontinent revealed

Researchers from Royal Holloway University, The Australian National University and Geoscience Australia, have helped clear up previous uncertainties on how the plates evolved and where they should be positioned when drawing up a picture of the past.

Dr Lloyd White from the Department of Earth Sciences at Royal Holloway University said: "The Earth's tectonic plates move around through time. As these movements occur over many millions of years, it has previously been difficult to produce accurate maps of where the continents were in the past.

"We used a computer program to move geological maps of Australia, India and Antarctica back through time and built a 'jigsaw puzzle' of the supercontinent Gondwana. During the process, we found that many existing studies had positioned the plates in the wrong place because the geological units did not align on each plate."

The researchers adopted an old technique used by people who discovered the theories of continental drift and plate tectonics, but which had largely been ignored by many modern scientists.

"It was a simple technique, matching the geological boundaries on each plate. The geological units formed before the continents broke apart, so we used their position to put this ancient jigsaw puzzle back together again," Dr White added.

"It is important that we know where the plates existed many millions of years ago, and how they broke apart, as the regions where plates break are often where we find major oil and gas deposits, such as those that are found along Australia's southern margin."

A video demonstrating the ancient jigsaw puzzle can be viewed here: http://vimeo.com/68311221

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

we are focus on the following fields,and hope we can help you.

Resistors Texas Instruments(TI) Switches MURATA Rectifier IDT IC LINEAR Metal Can Packages Chip Fuses Xilinx HARRIS Diodes Inc Thin Film NXP Zener Atmel IC chip Filter saws Thick Film Cypress IC Voltage Regulators ALTERA Digital Other Parts Fleld Effect Military IC AVX Kingbrigt LED IC(Integrated Circuits) ON IR transistor PANASONIC AD Capacitor Current Sensors ROHM VISHAY Resistor Arrays Dialight LED Fast Recovery NEC
http://www.suvsystem.com/a/3494.aspx

New insights concerning the early bombardment history on Mercury

Recent images from NASA's MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft provided new insights showing that at least the younger plains resulted from vigorous volcanic activity. Yet scientists were unable to establish limits on how far into the past this volcanic activity may have occurred, or how much of the planet's surface may have been resurfaced by very old volcanic plains.

Now, a team of scientists has concluded that the oldest visible terrains on Mercury have an age of 4 billion to 4.1 billion years, and that the first 400 to 500 million years of the planet's evolution are not recorded on its surface. To reach its conclusion, the team measured the sizes and numbers of craters on the most heavily cratered terrains using images obtained by the MESSENGER spacecraft during its first year in orbit around Mercury. Team members then extrapolated to Mercury a model that was originally developed for comparing the Moon's crater distribution to a chronology based on the ages of rock samples gathered during the Apollo missions.

"By comparing the measured craters to the number and spatial distribution of large impact basins on Mercury, we found that they started to accumulate at about the same time, suggesting that the resetting of Mercury's surface was global and likely due to volcanism," said lead author Dr. Simone Marchi, who has a joint appointment between two of NASA's Lunar Science Institutes, one at the SwRI in Boulder and another at the Lunar and Planetary Institute in Houston.

Those results set the age boundary for the oldest terrains on Mercury to be contemporary with the so-called Late Heavy Bombardment (LHB), a period of intense asteroid and comet impacts recorded in lunar and asteroidal rocks and by the numerous craters on the Moon, Earth, and Mars, as well as Mercury.

"Meanwhile, the age of the youngest and broadest volcanic provinces visible on Mercury was determined to be about 3.6 billion to 3.8 billion years ago, just after the end of the Late Heavy Bombardment," Marchi said.

Altogether, the results indicate that the time agreement between the onset of the LHB and the global resurfacing of Mercury implies not only that the resurfacing was due to volcanism, but also, according to Chapman, that "the impact of large projectiles hitting Mercury's thin solid crust during the LHB may have enhanced the observed global resurfacing."

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

we are focus on the following fields,and hope we can help you.

Chip Ferrite Beads INTERSIL IR transistor PANASONIC ST Transistors Freescale ELPIDA MAXIM Switching Ligitek LED MURATA Rectifier Fleld Effect Thin Film Multi-units Thick Film AD NXP ROHM Cypress IC Chip Fuses NEC LED Infineon Technologies Metal Can Packages IR Voltage Regulators BB NEC Current Sensors TDK LINEAR LED part Digital SANYO About US components ON Military IC Capacitor
http://www.suvsystem.com/a/3489.aspx

White dwarf star throws light on possible variability of a constant of Nature

July 4, 2013 — An international team led by the University of New South Wales has studied a distant star where gravity is more than 30,000 times greater than on Earth to test its controversial theory that one of the constants of Nature is not a constant.

Share This:

Dr Julian Berengut and his colleagues used the Hubble Space Telescope to measure the strength of the electromagnetic force -- known as alpha -- on a white dwarf star.

Their results, which do not contradict the variable constant theory, are to be published in the journal Physical Review Letters. Dr Berengut, of the UNSW School of Physics, said the team's previous research on light from distant quasars suggests that alpha -- known as the fine-structure constant -- may vary across the universe.

"This idea that the laws of physics are different in different places in the cosmos is a huge claim, and needs to be backed up with solid evidence," he says.

"A white dwarf star was chosen for our study because it has been predicted that exotic, scalar energy fields could significant alter alpha in places where gravity is very strong."

"Scalar fields are forms of energy that often appear in theories of physics that seek to combine the Standard Model of particle physics with Einstein's general theory of relativity."

"By measuring the value of alpha near the white dwarf and comparing it with its value here and now in the laboratory we can indirectly probe whether these alpha-changing scalar fields actually exist."

White dwarfs are very dense stars near the ends of their lives. The researchers studied the light absorbed by nickel and iron ions in the atmosphere of a white dwarf called G191-B2B. The ions are kept above the surface by the star's strong radiation, despite the pull of its extremely strong gravitational field.

"This absorption spectrum allows us to determine the value of alpha with high accuracy. We found that any difference between the value of alpha in the strong gravitational field of the white dwarf and its value on Earth must be smaller than one part in ten thousand," Dr Berengut says.

"This means any scalar fields present in the star's atmosphere must only weakly affect the electromagnetic force." Dr Berengut said that more precise measurements of the iron and nickel ions on earth are needed to complement the high-precision astronomical data.

"Then we should be able to measure any change in alpha down to one part per million. That would help determine whether alpha is a true constant of Nature, or not."

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

we are focus on the following fields,and hope we can help you.

Fast Recovery NS IC Zener Chip Fuses BB Low Ohmic Microchip IC components LED part Other Parts Renesas parts SMD ZENER Semiconductor Civil IC Chip Ceramic Resistors FAIRCHILD diodes TOSHIBA LITTELFUSE Discrete MOSFET ROHM Diodes Inc Current Sensors YAGEO NEC IDT IC Resistor Arrays Military IC Texas Instruments DC ZENER Semiconductor TI IC INFLNEON Digital Atmel IC Resistor Networks Texas Instruments Freescale Semiconductor Infineon Technologies IR INTERSIL Dis Semiconductor
http://www.suvsystem.com/a/3483.aspx

Study of mitochondrial DNA ties ancient remains to living descendants

The findings are reported in the journal PLOS ONE.

The researchers compared the complete mitochondrial genomes of four ancient and three living individuals from the north coast of British Columbia, Canada. This region is home to the indigenous Tsimshian, Haida and Nisga'a people, all of whom have oral traditions and some written histories indicating that they have lived in the region for uncounted generations. Archaeological sites, some with human remains, date back several millennia. But until the current study, nothing definitively tied the current inhabitants of the area to the ancient human remains found there, some of which are 5,000 to 6,000 years old.

"Having a DNA link showing direct maternal ancestry dating back at least 5,000 years is huge as far as helping the Metlakatla prove that this territory was theirs over the millennia," said Barbara Petzelt, an author and participant in the study and liaison to the Tsimshian-speaking Metlakatla community, one of the First Nations groups that participated in the study.

Only one previous study of ancient remains found in the Americas -- the hair of an Eskimo man who lived in Greenland 3,400 to 4,500 years ago -- analyzed all of the ancient mitochondrial DNA sequences (the mitochondrial genome, or mitogenome). Most such studies look at only a small subset (less than 2 percent) of mitogenomic sequences.

The new analysis was made possible by technological advances that cut the cost and complexity of sequencing ancient DNA.

"This is the beginning of the golden era for ancient DNA research because we can do so much now that we couldn't do a few years ago because of advances in sequencing technologies," said University of Illinois anthropology and Institute for Genomic Biology professor Ripan Malhi, who led the analysis. "We're just starting to get an idea of the mitogenomic diversity in the Americas, in the living individuals as well as the ancient individuals."

Focusing on the mitogenome is a good way to study the evolutionary history of these groups, Malhi said. DNA is often degraded in ancient remains, and unlike nuclear DNA, which is present in only two copies per cell, mitochondria are abundant in cells, giving researchers many DNA duplicates to sequence and compare.

Mitochondrial DNA does not recombine with paternal DNA and is passed down from mother to offspring more or less intact. This makes it easier to track unique sequences through the generations. And since the participants in the study belong to matrilineal cultures, their oral histories can be compared to evidence from the maternal lineages reflected in the mitogenome.

Another complication associated with analyzing nuclear DNA in Native Americans involves the European influence, Malhi said.

"There's a pattern of European males mixing with Native American females after European contact and so lots of the Y chromosomes in the community trace back to Europe," he said. The mitogenome offers a clearer picture of Native American lineages before European contact, he said.

Scientists, including David Archer, an anthropology professor at Northwest Community College in Prince Rupert, and biological anthropologist and co-author Jerome Cybulski, of the Canadian Museum of Civilization in Gatineau, Quebec, have worked since the 1960s to recover and analyze human remains and ancient structures in the region around Prince Rupert.

One particularly fruitful site, the Lucy Islands, yielded human remains and evidence of a house structure that is 5,300 to 6,400 years old. Careful study revealed that one of the ancient individuals found there, a young adult female, lived roughly 5,500 years ago. Her mitogenome matched that of another female found on Dodge Island, near the city of Prince Rupert. Her remains were about 2,500 years old. A living participant in the study also carried the same mitogenomic signature, the researchers found, and so is a direct maternal descendant of those two women or their mothers.

Three other living participants host a different mitogenomic sequence that matches another individual found on Dodge Island who lived about 5,000 years ago.

The archaeological sites also point to a long period of continuous occupation and stability in terms of the types of structures people used and the ways they used them, Archer said.

"Archaeology is one important source of information about the past, and oral traditions give us a lot of verifiable information about the past cultural events and patterns," he said. "But the genetic information is something that is immediately recognizable. If somebody is told that their DNA links to somebody who was present 2,500 years ago and also to someone who was present 5,500 years ago, you can summarize that in a sentence and it's very easily understood and it's exciting."

The new findings were the result of an unusual effort by the researchers to enlist the help of the indigenous people they study.

"I believe this is really a unique collaboration," said Joycelynn Mitchell, a Metakatla co-author and participant in the study. "It's very exciting to be able to have scientific proof that corroborates what our ancestors have been telling us for generations. It's very amazing how fast technology is moving to be able to prove this kind of link with our past."

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

we are focus on the following fields,and hope we can help you.

KEMET Renesas parts Cyclone FPGA Digital About US DIODES ROHM Transistors AVX Civil IC MAXIM IC(Integrated Circuits) chip Filter saws ON ELPIDA Low-power Semiconductor Configuration Devices Texas Instruments IR transistor Discrete Semi Other Parts regulator Semiconductor Switches MURATA Atmel IC INTERSIL Diodes Vishay resistors Ligitek LED Dialight LED Zener Military IC components Tantalum LINEAR TI IC Multi-units TDK Cyclone II FPGA NS IC
http://www.suvsystem.com/a/3481.aspx

Archaeologists unearth carved head of Roman god in ancient rubbish dump

July 4, 2013 — An 1,800-year-old carved stone head of what is believed to be a Roman god has been unearthed in an ancient rubbish dump.

Share This:

Archaeologists made the discovery at Binchester Roman Fort, near Bishop Auckland, in County Durham.

First year Durham University archaeology student Alex Kirton found the artefact, which measures about 20cm by 10cm, in buried late Roman rubbish within what was probably a bath house.

The sandstone head, which dates from the 2nd or 3rd century AD, has been likened to the Celtic deity Antenociticus, thought to have been worshipped as a source of inspiration and intercession in military affairs.

A similar sandstone head, complete with an inscription identifying it as Antenociticus, was found at Benwell, in Newcastle upon Tyne, in 1862.

Dr David Petts, Lecturer in Archaeology at Durham University, said: "We found the Binchester head close to where a small Roman altar was found two years ago. We think it may have been associated with a small shrine in the bath house and dumped after the building fell out of use, probably in the 4th century AD.

"It is probably the head of a Roman god -- we can't be sure of his name, but it does have similarities to the head of Antenociticus found at Benwell in the 19th century.

"We may never know the true identity of this new head, but we are continuing to explore the building from which it came to help us improve our understanding of late Roman life at Binchester and the Roman Empire's northern frontier in Northern England.

"Antenociticus is one of a number of gods known only from the northern frontier, a region which seems to have had a number of its own deities.

"It's also an excellent insight into the life and beliefs of the civilians living close to the Roman fort. The style is a combination of classical Roman art and more regional Romano-British traditions. It shows the population of the settlement taking classical artistic traditions and making them their own."

Alex, 19, from Bishop's Stortford, in Hertfordshire, said: "As an archaeology student this is one of the best things and most exciting things that could have happened."

He added: "It was an incredible thing to find in a lump of soil in the middle of nowhere -- I've never found anything remotely exciting as this."

Dr David Mason, Principal Archaeologist with the site's owner, Durham County Council, said: "The head is a welcome addition to the collection of sculpture and inscriptions from Binchester. Previous religious dedications from the site feature deities from the classical pantheon of gods and goddesses such as the supreme god Jupiter and those associated with healing and good health such as Aesculapius, Salus and Hygeia.

"This one however appears to represent a local Romano-Celtic god of the type frequently found in the frontier regions of the Empire and probably representing the conflation of a classical deity with its local equivalent. The similarity with the head of Antenociticus is notable, but this could be a deity local to Binchester."

The Binchester head is African in appearance, but Dr Petts, who is also Associate Director of Durham University's Institute of Medieval and Early Modern Studies, said experts were unsure whether these features were deliberate or coincidental.

He explained: "This is something we need to consider deeply. If it is an image of an African, it could be extremely important, although this identification is not certain."

Dr Mason added: "The African style comparison may be misleading as the form is typical of that produced by local craftsmen in the frontier region."

The find was made as part of a five year project at Binchester Roman Fort which is shedding new light on the twilight years of the Roman Empire.

The Binchester dig is a joint project between Durham University's Department of Archaeology, site owner Durham County Council, Stanford University's Archaeology Centre and the Architectural and Archaeological Society of Durham and Northumberland.

Each summer, undergraduate archaeology students from Durham and the United States are joined by volunteer members of the public to painstakingly reveal more fascinating details from Binchester's past.

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

we are focus on the following fields,and hope we can help you.

Bacteria communicate to help each other resist antibiotics

Dr. Miguel Valvano and first author Omar El-Halfawy, PhD candidate, show that the more antibiotic resistant cells within a bacterial population produce and share small molecules with less resistant cells, making them more resistant to antibiotic killing. These small molecules, which are derived from modified amino acids (the building blocks used to make proteins), protect not only the more sensitive cells of B. cenocepacia but also other bacteria including a highly prevalent CF pathogen, Pseudomonas aeruginosa, and E. coli. The research is published in PLOS ONE.

"These findings reveal a new mechanism of antimicrobial resistance based on chemical communication among bacterial cells by small molecules that protect against the effect of antibiotics," says Dr. Valvano, adjunct professor in the Department of Microbiology and Immunology at Western's Schulich School of Medicine & Dentistry, currently a Professor and Chair at Queen's University Belfast. "This paves the way to design novel drugs to block the effects of these chemicals, thus effectively reducing the burden of antimicrobial resistance."

"These small molecules can be utilized and produced by almost all bacteria with limited exceptions, so we can regard these small molecules as a universal language that can be understood by most bacteria," says El-Halfawy, who called the findings exciting. "The other way that Burkholderia communicates its high level of resistance is by releasing small proteins to mop up, and bind to lethal antibiotics, thus reducing their effectiveness." The next step is to find ways to inhibit this phenomenon.

The research, conducted at Western, was funded by a grant from Cystic Fibrosis Canada and also through a Marie Curie Career Integration grant.

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

we are focus on the following fields,and hope we can help you.

Multi-units Chip Inductors Industrial IC PANASONIC NXP Vishay resistors Cypress IC TI IC ST Rectifier AVX Capacitors CYCLONE III NEC ON LED Chip Fuses Kingbrigt LED Digital Texas Instruments KEMET Texas Instruments(TI) Resistor Networks Resistors DIODES ST IC(Integrated Circuits) MURATA Configuration Devices chip Filter saws IR transistor TOSHIBA Switching FAIRCHILD diodes Switches Connectors Chip Ceramic regulator Semiconductor AVX Ligitek LED LINEAR
http://www.suvsystem.com/a/3475.aspx

Cockatoos 'pick' puzzle box locks: Cockatoos show technical intelligence on a five-lock problem

July 4, 2013 — A species of Indonesian parrot can solve complex mechanical problems that involve undoing a series of locks one after another, revealing new depths to physical intelligence in birds.

Share This:

A team of scientists from Oxford University, the University of Vienna, and the Max Planck Institute, report in PLOS ONE a study in which ten untrained Goffin's cockatoos [Cacatua goffini] faced a puzzle box showing food (a nut) behind a transparent door secured by a series of five different interlocking devices, each one jamming the next along in the series.

To retrieve the nut the birds had to first remove a pin, then a screw, then a bolt, then turn a wheel 90 degrees, and then shift a latch sideways. One bird, called 'Pipin', cracked the problem unassisted in less than two hours, and several others did it after being helped either by being presented with the series of locks incrementally or being allowed to watch a skilled partner doing it.

Watch a video of cockatoos solving the puzzle box: http://www.zoo.ox.ac.uk/group/kacelnik/lb_movie_s1.mov

The scientists were interested in the birds' progress towards the solution, and on what they knew once they had solved the full task.

The team found that the birds worked determinedly to sort one obstacle after another even though they were only rewarded with the nut once they had solved all five devices. The scientists suggest that the birds seemed to progress as if they employed a 'cognitive ratchet' process: once they discovered how to solve one lock they rarely had any difficulties with the same device again. This, the scientists argue, is consistent with the birds having a representation of the goal they were after.

After the cockatoos mastered the entire sequence the scientists investigated whether the birds had learnt how to repeat a sequence of actions or instead responded to the effect of each lock.

Dr Alice Auersperg, who led the study at the Goffin Laboratory at Vienna University, said: 'After they had solved the initial problem, we confronted six subjects with so-called 'Transfer tasks' in which some locks were re-ordered, removed, or made non-functional. Statistical analysis showed that they reacted to the changes with immediate sensitivity to the novel situation.'

Professor Alex Kacelnik of Oxford University's Department of Zoology, a co-author of the study, said: 'We cannot prove that the birds understand the physical structure of the problem as an adult human would, but we can infer from their behaviour that they are sensitive to how objects act on each other, and that they can learn to progress towards a distant goal without being rewarded step-by-step.'

Dr Auguste von Bayern, another co-author from Oxford University said: 'The birds' sudden and often errorless improvement and response to changes indicates pronounced behavioural plasticity and practical memory. We believe that they are aided by species characteristics such as intense curiosity, tactile exploration techniques and persistence: cockatoos explore surrounding objects with their bill, tongue and feet. A purely visual explorer may have never detected that they could move the locks.'

Professor Kacelnik said: 'It would be too easy to say that the cockatoos understand the problem, but this claim will only be justified when we can reproduce the details of the animals' response to a large battery of novel physical problems.'

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

we are focus on the following fields,and hope we can help you.

Bipolar About US NS IC TOSHIBA IR transistor ON TI IC DIODES HARRIS Xilinx Resistor Arrays AD Civil IC Tantalum MAXIM Chip Inductors Dis Semiconductor Voltage Regulators NXP Connectors Texas Instruments chip Filter saws Low-power Semiconductor Zener Transistors Freescale TDK High Precision Texas Instruments DC AVX Capacitors Military IC Fleld Effect Thin Film BB Resistors VISHAY SMD ZENER Semiconductor Digital INFLNEON Rectifier IC(Integrated Circuits)
http://www.suvsystem.com/a/3472.aspx

Hawkmoths use ultrasound to combat bats

July 4, 2013 — For years, pilots flying into combat have jammed enemy radar to get the drop on their opponents. It turns out that moths can do it, too.

Share This:

A new study co-authored by a University of Florida researcher shows hawkmoths use sonic pulses from their genitals to respond to bats producing the high-frequency sounds, possibly as a self-defense mechanism to jam the echolocation ability of their predators.

Echolocation research may be used to better understand or improve ultrasound as a vital tool in medicine, used for observing prenatal development, measuring blood flow and diagnosing tumors, among other things. The study appears online today in the journal Biology Letters.

Study co-author Akito Kawahara, assistant curator of Lepidoptera at the Florida Museum of Natural History on the UF campus, said ultrasound has only been demonstrated in one other moth group.

"This is just the first step toward understanding a really interesting system," Kawahara said. "Echolocation research has been focused on porpoises, whales and dolphins. We know some insects produce the sounds, but this discovery in an unrelated animal making ultrasound, potentially to jam the echolocation of bats, is exciting."

Hawkmoths are major pollinators and some are agricultural pests. Researchers use the insects as model organisms for genetic research due to their large size.

Previous research shows tiger moths use ultrasound as a defense mechanism. While they produce the sound using tymbals, a vibrating membrane located on the thorax, hawkmoths use a system located in the genitals. Scientists found at least three hawkmoth species produce ultrasonic sound, including females. Researchers believe hawkmoths may produce the sound as a physical defense, to warn others or to jam the bats' echolocation, which confuses the predators so they may not identify an object or interpret where it is located, Kawahara said.

The study was conducted in Malaysia, which has the highest diversity of hawkmoths worldwide, and funded by a National Science Foundation grant of about $500,000. Kawahara also conducted research in the jungles of Borneo and the lower Amazon.

"So much work has been focused on animals that are active during the day, but there are a lot of really interesting things happening at night, and we just don't know a lot about what is actually going on -- because we can't hear or see it," Kawahara said. "The fascinating part is that there are a lot of new discoveries to be made. It's a totally unknown, unexplored system."

Kawahara's team from the Florida Museum's McGuire Center for Lepidoptera and Biodiversity used high-energy lamps to capture the hawkmoths in the jungle. Study co-author Jesse Barber's team from Boise State University played pre-recorded bat sounds to the insects, and all researchers studied their behavior. With the insects tethered inside an enclosed sound rig containing an ultrasonic microphone and speaker connected to two laptop computers, researchers recorded the sounds the hawkmoths made in response to being touched and hearing the echolocation sounds. The responsive species include Cechenena lineosa, Theretra boisduvalii and Theretra nessus.

"As a museum, we are creating a library of life," Kawahara said. "Museum specimens are usually preserved immediately, but we are trying to understand the behavior of these organisms so that we have a record of their behavior along with the specimen and DNA. This is why there are so many interesting things we're starting to discover."

Hawkmoths are among the fastest and most proficient flying insects, and more than 1,400 species occur worldwide. Their long proboscis, or mouthpart, makes them important pollinators, since many plants may only be pollinated by hawkmoths.

Study collaborators plan to continue researching the use of ultrasound in hawkmoths, focusing on the evolution of the insects to see if other hawkmoth species use this system, Kawahara said.

"We think hawkmoths are a primary food source for bats because none appear to be chemically defended, which is why they have evolved anti-bat ultrasound strategies," Kawahara said. "Hawkmoths have evolved different ways of avoiding bats -- I can't even explain how amazing the system is, it is just fascinating."

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

we are focus on the following fields,and hope we can help you.

订阅：博文 (Atom)