#Yeast reveals secret of hitchhiker mutations It takes a group effort of genetic mutations to give organisms the best shot at evolutionary survival a new study suggests.
Evolution occurs when an individual experiences a spontaneous beneficial mutation in its genome that improves its ability to adapt to its environment.
The common view was that a single mutation could boost the survival of an individual
which would then reproduce and pass on the mutation to its offspring. Instead researchers studying 1000 generations of adaptation in 40 yeast populations have found that rather than just one mutation causing enhanced survival about five to seven mutations are required.
These extra mutations are termed hitchhikers because they don t appear to contribute to the enhanced fitness of the organism Our study indicates that evolution is more of a group effort says Gregory Lang an associate research scholar in the laboratory of David Botstein at Princeton university s Lewis-Sigler Institute
for Integrative Genomics. Lang is first author on the paper which appears in the journal Nature.
Drivers and hitchhikers The finding goes against the traditional view of evolution being determined by individual mutations that provide a large fitness advantage by themselves says Michael Desai a former Princeton fellow who is currently at Harvard university.
We found that small groups which we call cohorts of mutations were associated with increased survival.
No single mutation is driving adaptation. The whole group which includes hitchhikers drives adaptation together.
The relatively small subset of gene mutations that were found to enhance survival Botstein says suggests that there are only a limited number of ways in
which organisms can substantially increase their fitness. Understanding the basic process in yeast translates to other organisms he says.
The knowledge of how mutations drive evolution can inform our understanding of how tumors resist chemotherapeutics
and how bacteria evolve resistance to antibiotics. Although the researchers refer to the groups of mutations as containing drivers
and hitchhikers Desai says that additional research is being done to explore which mutations are necessary for adaptation and
which ones are along for the ride. He noted that the mutations are located not near each other nor do they appear to have similar functions.
The study helps expand our understanding of how evolution arises from a combination of genetic mutations
which are thought of as occurring spontaneously and environmental pressures says Botstein. We ve shown that this first component the genetics involves not just one gene mutation
but several that need to coexist before evolution can happen. By following genomic changes across cell populations over time this study allows a rare glimpse of evolution in progress says Stefan Maas of the National institute of health s National Institute of General Medical sciences which partially funded the research.
This systems biology approach yields insights that could help us understand how mutations spread through other evolving systems such as cancer cells
or disease-causing microbes. Previous evidence suggests that yeast may experience beneficial mutations that inactivate genes they no longer need.
For example Lang and Botstein in collaboration with Andrew Murray at Harvard university reported in 2009 that if grown in conditions where the yeast can only reproduce asexually mutations that inactivate genes for proteins involved in sexual reproduction boost survival
because the organisms do not waste metabolic energy producing unneeded proteins. The team which includes researchers from Washington University School of medicine plans to explore
whether the mutations identified in the new study confer specific survival advantages. The National Science Foundation Graduate Research Fellowship the National Institute of General Medical sciences Centers of Excellence the National institutes of health the James S. Mcdonnell Foundation the Alfred P. Sloan
Foundation and the Harvard Milton Fund helped support the study. Source: Princeton Universityyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license e
##Shifty#neutrinos hint at antimatter mystery Boston University Duke university Stony Brook University University of Pittsburgh University of Rochester University of Washington Posted by Leonor Sierra-Rochester
on July 24 2013u. ROCHESTER/STONY BROOK (US)# Scientists have announced the first definitive observation of the transformation of muon neutrinos to electron neutrinos#a type of neutrino oscillation that had never been observed.#
#In 1998 the discovery of neutrino oscillation in the atmospheric neutrinos by the Super-Kamiokande experiment led us to a new journey into the fascinating and mysterious world of neutrinos
which is full of surprises#says Chang Kee Jung professor of physics at Stony Brook University and international co-spokesperson for the T2k Collaboration.#
#This discovery of electron neutrino appearance from muon neutrinos by the T2k experiment opens another critical door in our journey to unveil the secrets of our universe.#
The experiment shows that researchers can now accurately observe the type of neutrino oscillation that will need to be studied in detail in future experiments aiming to measure CP violation explains Steven Manly professor of physics at the University of Rochester and part of the collaboration.
and continue to collect sufficient data to explore this possible CP violation.##One in a trillionthe T2k experiment based in Tokai Japan expects to collect 10 times more data in the near future including data with an antineutrino beam.
Manly explains that neutrinos are notoriously difficult to study and the oscillation that the researchers seek can be mimicked by other processes.
For that reason the University of Rochester group has focused on understanding these other processes to ensure that what is measured is really the neutrino oscillation they have sought.
The researchers have gathered now 3. 5 times more data and this transformation is established firmly. The probability that random statistical fluctuations alone would produce the observed excess of electron neutrinos is less than one in a trillion.
The neutrino beam is monitored by a detector complex in Tokai and aimed at the gigantic Super-Kamiokande underground detector in Kamioka near the west coast of Japan 295 kilometers (185 miles) away from Tokai.
An analysis of the data from the Super-Kamiokande detector associated with the neutrino beam time from J-PARC reveals that there are more electron neutrinos (a total of 28 events) than would be expected (4. 6 events) without this new process.
The current T2k collaboration consists of over 400 physicists from 59 institutions in 11 countries.
Funded by the US Department of energy Office of Science the US T2k collaborating team includes Boston University;
University of California Irvine; University of Colorado; Colorado State university; Duke university; Louisiana State university; Stony Brook University;
University of Pittsburgh; University of Rochester; and University of Washington (Seattle. Sources: University of Rochester Stony Brook Universityyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license v
#iphone artists help solve#fat finger#problem CARNEGIE MELLON (US) Using the data amassed with an iphone drawing game,
researchers have built a tool that improves touchscreen art. The fingers of thousands of people who created sketches of Brad pitt
and Angelina jolie on their iphones can collectively guide and correct the drawing strokes of subsequent touchscreen users in an application created by researchers at Carnegie mellon University and Microsoft Research.
The app compensates for the at fingerproblem associated with touchscreens, automatically correcting a person drawing strokes
while preserving the user artistic style. ur goal was to make it invisible to the user, so people wouldn even be aware the correction is taking place,
says Alex Limpaecher, a Ph d. student in Carnegie mellon University computer science department. Adrien Treuille, associate professor of computer science and robotics, says the drawing assistance app is just one example of how Big data can be used to enhance drawing
and writing on touchscreens and even provide deep insights into art and perception. The trick has been to create drawing databases large enough to leveragen obstacle that he
and his research team surmounted with an iphone drawing game. The game they created, Drawafriend
motivated thousands of people to sketch Brad pitt, Angelina jolie, and other celebrities. In its first week, the game generated 1, 500 images a day.
The game is still operational and the resulting database now includes more than 17,000 images, each with stroke-by-stroke information about how it was created. e are in the middle of a Big data revolution,
Treuille says. ee found that Big data can be used to do amazing things. But success is not inevitable;
you have to have the dataset first. With Drawafriend, wee found a way to use crowdsourcing to create this critical resource for a data-impoverished phenomenon.
Real-time correction In Drawafriend, players take turns drawing faces of celebrities or of mutual friends from Facebook.
One player draws the face, tracing over a photo. As the portrait comes together, stroke by stroke,
the other player guesses which letters are in the name of the subject of the portrait,
much like in the game Hangman. Limpaecher said the game accomplishes a number of objectives.
Not only does it create a large database of drawing strokes the game motivates players to try to draw as best they can
and also evaluates the quality of the drawing by tracking the success of the other playersguesses.
The team used the database of celebrity photos to create a simple stroke-correction method.
By determining the consensus of the strokes from the database drawings, they found that they could cancel out the oisecaused by large fingers trying to draw on small screens.
This correction occurs in real-time so the person is not aware that the drawing is being cleaned up even as it is being created.
Freehand too? Related Articles On Futurity robot eyes 525 Carnegie mellon University How to turn robots into social butterflies blurry man in art museum Michigan State university Men focus more on'brand
'when judging art health-care-cartoons 525 University of Rochester Cartoons depict 100 years of health care debate Other applications abound.
For instance, Limpaecher says algorithms have previously been created for identifying whether a person is drawing a face,
or a human figure, or other subject, but large databases have not been available to enable their use.
Likewise, the correction function now used for sketches based on photos could be modified for freehand drawing.
To broaden the database the game could be modified to include drawings other than portrait sketches. Treuille says databases of drawings also could be used to address more basic questions.
Drawings often differ substantially in appearance from their real-life subjects, he notes, which suggests that databases of drawings could be mined for insights into human perception.
Such findings, in turn, might help in developing better object recognition or scene analysis for computer vision systems.
The databases also might be used to create teaching tools to improve the artistic techniques of students,
he adds. Limpaecher presented the findings at SIGGRAPH 2013 the International Conference on Computer graphics and Interactive Techniques, in Anaheim, California.
In addition to Treuille, the other team members were Nicholas Feltman, a Ph d. student in computer science, and Michael Cohen, principal researcher in Microsoft Research Interactive Visual Media Group.
The National Science Foundation, Google, Qualcomm, Adobe, Intel, and the Okawa Foundation supported the research a
##Solar steam kills germs while off the grid RICE (US) A new sterilization system uses nanomaterials to convert 80 percent of the energy in sunlight into heat,
and could be a boon for more than 2. 5 billion people who lack adequate sanitation.
The technology, described online in the early edition of Proceedings of the National Academy of Sciences,
offers two ways that solar steam can be used for sterilizationne setup to clean medical instruments and another to sanitize human waste. anitation
and sterilization are enormous obstacles without reliable electricity, says Naomi Halas, director of the Laboratory for Nanophotonics (LANP) at Rice university. olar steam efficiency at converting sunlight directly into steam opens up new possibilities for off-grid sterilization that simply aren available today In a previous study last year,
Halas and colleagues showed that olar steamwas so effective at direct conversion of solar energy into heat that it could even produce steam from ice water. t makes steam directly from sunlight,
Solar steam efficiency comes from light-harvesting nanoparticles that were created at LANP by Rice graduate student Oara Neumann,
Neumann created a version of nanoshells that converts a broad spectrum of sunlightncluding both visible and invisible bandwidthsirectly into heat.
The technology has an overall energy efficiency of 24 percent. Photovoltaic solar panels, by comparison, typically have an overall energy efficiency of around 15 percent.
When used in the autoclaves in the tests, the heat and pressure created by the steam were sufficient to kill not just living microbes but also spores and viruses. In the study,
Neumann says. e needed to create a system that could handle the waste of a family of four with just two treatments per week,
The researchers hope to conduct the first field tests of the solar steam waste sterilizer at three sites in Kenya. anitation technology isn glamorous,
but it a matter of life and death for 2. 5 billion people, Halas says. or this to really work,
you need a technology that can be completely off-grid, that not that large, that functions relatively quickly, is easy to handle
The study was supported by the Bill & Melinda Gates Foundation and by the Welch Foundation B
but no one yet has found the smoking gun, says Mike Lamb, an assistant professor of geology at California Institute of technology (Caltech).
Although the new findings are far from proof of the existence of an ancient ocean,
says postdoctoral scholar Roman Dibiase. Most of the northern hemisphere of Mars is flat and at a lower elevation than the southern hemisphere,
After the river dries up, the finer materialuch as smaller grains of clay, silt, and sandround the river erodes away, leaving behind the coarser stuff.
and the topographic data can distinguish changes in elevation at a resolution of 1 meter.
Using this data the researchers analyzed the stratigraphic layers of the inverted channels, piecing together the history of how sediments were deposited along these ancient rivers and streams.
if they yield more evidence for an ocean. n our work and that of othersncluding the Curiosity rovercientists are finding a rich sedimentary record on Mars that is revealing its past environments,
which include rain, flowing water, rivers, deltas, and potentially oceans, Lamb says. oth the ancient environments on Mars
and the planet sedimentary archive of these environments are turning out to be surprisingly Earthlike. This research was supported by the National Science Foundation
NASA, and Caltech
#Graphene#s jagged edge can easily slice cells Brown University right Original Study Posted by Kevin Stacey-Brown on July 10 2013brown (US) the jagged edges of tiny graphene sheets
can spell trouble for human cells. New research shows the sharp edges can puncture cell membranes.
The new insight may be helpful in finding ways to minimize the potential toxicity of graphene says Agnes Kane chair of the pathology and laboratory medicine department at Brown and one of the study s authors.
If there some feature that is responsible for its toxicity then maybe the engineers can engineer it out.
Is nanotech toxic? Discovered about a decade ago graphene is a sheet of carbon just one atom thick.
Commercial applications in small electronic devices solar cells batteries and even medical devices are just around the corner.
or implanted as components of new biomedical technologies says Robert Hurt an engineering professor and one of the study s authors.
So we want to understand how they interact with cells once inside the body These latest findings come from an ongoing collaboration between biologist engineers
and material scientists at Brown aimed at understanding the toxic potential of a wide variety of nanomaterials.
Oddly shaped flakes Preliminary research by Kane s biology group had shown that graphene sheets can indeed enter cells
Huajian Gao professor of engineering tried to explain those results using powerful computer simulations but he ran into a problem.
The energy barrier required for a sheet to cut the membrane was simply too high even
or peeled away from thicker chunks of graphite the sheets come off in oddly shaped flakes with jagged protrusions called asperities.
Under the microscope Annette von dem Bussche assistant professor of pathology and laboratory medicine was able to verify the model experimentally.
Electron microscope images confirmed that graphene entered the cells starting at rough edges and corners. The experiments showed that even fairly large graphene sheets of up to 10 micrometers could be internalized completely by a cell.
That allows us to better interpret the biological impacts of these materials. It s really a wonderful collaboration.
But Kane says this initial study provides an important start in understanding the potential for graphene toxicity.
This is about the safe design of nanomaterials she says. Theye man-made materials so we should be able to be clever
Other contributors to the study were Brown graduate students Yinfeng Li (now a professor at Shanghai Jiao Tong University) Hongyan Yuan and Megan Creighton.
Brown University. You are free to share this article under the Creative Commons Attribution-No Derivs 3. 0 Unported license l
which recorded acoustic data and high-resolution movements as the animals were exposed to the controlled sounds.
That area of the ocean is also the site of military training and testing exercises that involve loud mid-frequency sonar signals.
and an adjunct researcher at both Duke and the University of California Santa cruz. These findings help us understand risks to these animals from human sound
A related paper published July 3 by the same research team in Biology Letters has shown clear and even stronger responses of Cuvier s beaked whales to simulated mid-frequency sonar exposures.
##Streamloading puts video buffering on hold New york University Posted by James Devitt-NYU on June 26 2013nyu (US)# A new type of streaming technology that fuses streaming
and dodges screen freezes in mobile devices. It s the bane of streaming media#the endlessly spinning cursor on a dark screen or the final minutes of a favorite show freezing to a halt
when the wireless signal weakens. The new technology called streamloading could make spotty streaming and data-hogging downloads a thing of the past.
In the simplest terms streamloading makes use of a video format that splits the video into two layers#a base layer
Traditional streaming involves downloading 30 to 60 seconds of video ahead of time with the video quality and speed varying depending on wireless signal strength.
Streamloading allows users to pre-download the enhancement layer onto their devices in a location where wireless signal is strong#at home for example#and stream only the base layer at the time of viewing.
Shivendra S. Panwar professor of electrical and computer engineering the Polytechnic institute of New york University and the lead developer of streamloading estimates that the technique could remove as much as 75 percent of the streaming content from increasingly overloaded cellular wireless networks
while at the same time reducing high data usage charges for consumers Panwar explains that#in the best-case scenario we ll at the same time relieve some of the bandwidth crunch for wireless carriers
#Panwar along with a team of students who have been working on the prototype technology designed streamloading to be compatible with current digital rights management (DRM) protocols.
Although users will technically be downloading and saving content on their devices#something that s prohibited by streaming content services like Netflix#Panwar explains that
The National Science Foundation and the Center for Advanced Technology in Telecommunications (CATT) at NYU-Poly support the work.
#Graphene ribbons improve lithium ion batteries Anodes for lithium ion batteries built with ribbons of graphene perform better, tests show.
After 50 charge-discharge cycles, the proof-of-concept units retained a capacity that was still more than double that of the graphite currently used for LI battery anodes.
Rice university chemist James Tour and colleagues, who developed a method for unzipping nanotubes into graphene nanoribbons (GNRS),
One area ripe for improvement is the humble battery. In an increasingly mobile world battery capacity is becoming a bottleneck that generally limits devices to less than a day worth of use.
In the new experiments, the Rice lab mixed graphene nanoribbons and tin oxide particles about 10 nanometers wide in a slurry with a cellulose gum binder and a bit of water, spread it on a current collector
and encased it in a button-style battery. GNRS are a single atom thick and thousands of times longer than they are wide.
The GNRS not only separate and support the tin oxide but also help deliver lithium ions to the nanoparticles.
Major hurdle Lab tests showed initial charge capacities of more than 1 520 milliamp hours per gram (mah/g). Over repeated charge-discharge cycles, the material settled into a solid 825 mah/g. t took about two months to go through 50 cycles,
GNRS could also help overcome a prime difficulty with LI battery development. Lithium ions tend to expand the material they inhabit,
GNRS take a different approach by giving batteries a degree of flexibility, Tour says. raphene nanoribbons make a terrific framework that keeps the tin oxide nanoparticles dispersed
and keeps them from fragmenting during cycling, he adds. ince the tin oxide particles are only a few nanometers in size
and permitted to remain that way by being dispersed on GNR surfaces, the volume changes in the nanoparticles are not dramatic.
NRS also provide a lightweight, conductive framework, with their high aspect ratios and extreme thinness. The researchers point out the work is a tarting point for exploring the composites made from GNRS and other transition metal oxides for lithium storage applications.
Lin says the lab plans to build batteries with other metallic nanoparticles to test their cycling and storage capacities.
Boeing, the Air force Office of Scientific research, Sandia National Laboratory, and the Office of Naval Research supported the research u
#How pollen tubes know when to self-destruct Brown University rightoriginal Studyposted by David Orenstein-Brown on June 20 2013brown (US)# New research identifies genes that may control the death of pollen tubes during plant reproduction.##
##Pollination essential to much of life On earth requires the explosive death of the male pollen tube in the female ovule.
High school biology leaves off with this: In normal pollination sperm-carrying pollen grains land on the pistil s tip
In his lab at Brown University Mark Johnson associate professor of biology studies the true complexity of intercellular communications that conduct this process with exquisite precision.
The new paper in Current Biology describes the genetically prescribed life cycle of the pollen tube and how their expression destines the tube for self-sacrifice allowing flowering plants to reproduce.
Among the fundamental biology questions at play in the sex lives of flowers for example are how cells recognize each other know what to do
#Making the male listenin the new paper Johnson s group led by third-year graduate student Alexander Leydon sought to discover what convinces the male pollen tubes to stop growing
What they knew from a prior study is that the gene expression in pollen tubes that had grown through a pistil was much different than that of pollen tubes grown in the lab. Leydon s first step
therefore was to see which regulators of gene expression or transcription factors were at work in pistil-grown pollen tubes but not in the lab-grown ones.
when they aren t. He grew some normal arabadopsis plants some in which a mutation disabled only one of the transcription factors and other ones in
Future work Johnson says will include tracking down the relevant genes more fully and determining whether thionin is indeed the pollen tube buster that the genes
The work may also have implications beyond basic science Johnson says. Agronomists sometimes try to crossbreed species such as barley
and wheat in hopes of creating new crops. That can be done if the different species are related closely
and share the same number of chromosomes but fertilization often fails at the pollen tube burst
-and-release step. Among crop plants pollination means food.##Understanding this molecular back-and-forth at all the different levels and stages will be useful to either engineer the process
or introduce genetic diversity that will allow the reproductive process to be efficient even in difficult environmental conditions#Johnson says.
#Computer picks emotion based on brain scan CARNEGIE MELLON (US) For the first time, scientists have identified which emotion a person is experiencing based on brain activity.
combines functional magnetic resonance imaging (fmri) and machine learning to measure brain signals to accurately read emotions in individuals.
Identifying emotions based on neural activity builds on previous discoveries by Carnegie mellon University researchers Marcel Just and Tom M. Mitchell, who used similar techniques to create a computational model that identifies individualsthoughts
assistant professor of social and decision sciences and lead author of the study. t could be used to assess an individual emotional response to almost any kind of stimulus, for example, a flag, a brand name,
because the impact of film clips diminishes with repeated display. The researchers solved the problem by recruiting actors from the School of Drama. ur big breakthrough was my colleague Karim Kassam idea of testing actors,
says George Loewenstein, professor of economics and psychology. For the study, 10 actors were scanned at the Scientific Imaging & Brain Research center while viewing the words of nine emotions:
The computer model, constructed from using statistical information to analyze the fmri activation patterns gathered for 18 emotional words
The computer model achieved a rank accuracy of 0. 84. Rank accuracy refers to the percentile rank of the correct emotion in an ordered list of the computer model guesses;
random guessing would result in a rank accuracy of 0. 50. Next, the team took the machine learning analysis of the self-induced emotions to guess which emotion the subjects were experiencing
when they were exposed to the disgusting photographs. The computer model achieved a rank accuracy of 0. 91.
With nine emotions to choose from, the model listed disgust as the most likely emotion 60 percent of the time and as one of its top two guesses 80 percent of the time.
Finally, they applied machine learning analysis of neural activation patterns from all but one of the participants to predict the emotions experienced by the hold out participant.
different people tend to neurally encode emotions in remarkably similar ways, notes Amanda Markey, a graduate student in the department of social and decision sciences.
when the computer model made use of activation patterns in only one of a number of different subsections of the human brain. his suggests that emotion signatures aren limited to specific brain regions,
but produce characteristic patterns throughout a number of brain regions, says Vladimir Cherkassky, senior research programmer in the psychology department.
professor of psychology, director of the university Center for Cognitive Brain imaging, and neuroscientist, explains, e found that three main organizing factors underpinned the emotion neural signatures, namely the positive or negative valence of the emotion, its intensityild or strong,
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