Updates from June, 2016 Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 10:09 am on June 10, 2016 Permalink | Reply
    Tags: , , How honeybees do without males,   

    From phys.org: “How honeybees do without males” 

    physdotorg
    phys.org

    June 9, 2016

    1
    An isolated population of honeybees, the Cape bees, living in South Africa has evolved a strategy to reproduce without males. A research team from Uppsala University has sequenced the entire genomes of a sample of Cape bees and compared them with other populations of honeybees to find out the genetic mechanisms behind their asexual reproduction. Credit: Mike Allsopp

    Most animals reproduce sexually, which means that both males and females are required for the species to survive. Normally, the honeybee is no exception to this rule: the female queen bee produces new offspring by laying eggs that have been fertilised by sperm from male drones. However, one isolated population of honeybees living in the southern Cape of Africa has evolved a strategy to do without males.

    In the Cape bee, female worker bees are able to reproduce asexually: they lay eggs that are essentially fertilised by their own DNA, which develop into new worker bees. Such bees are also able to invade the nests of other bees and continue to reproduce in this fashion, eventually taking over the foreign nests, a behaviour called social parasitism.

    The explanation for this unique behaviour is unknown, however a research team from UU has come closer to uncovering the genetic mechanisms behind it. The team sequenced the entire genomes of a sample of Cape bees and compared them with other populations of honeybees that reproduce normally. They found striking differences at several genes, which can explain both the abnormal type of egg production that leads to reproduction without males, and the unique social parasitism behaviour.

    “The question of why this population of honeybees in South Africa has evolved to reproduce asexually is still a mystery. But understanding the genes involved brings us closer to understanding it. This study will help us to understand how genes control biological processes like cell division and behaviour. Furthermore understanding why populations sometimes reproduce asexually may help us to understand the evolutionary advantage of sex, which is a major conundrum for evolutionary biologists, says Matthew Webster”, researcher at the Department of Medical Biochemistry and Microbiology at Uppsala University.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 9:12 am on June 10, 2016 Permalink | Reply
    Tags: , , , Researchers demonstrate a 100x increase in the amount of information that can be 'packed into light',   

    From phys.org: “Researchers demonstrate a 100x increase in the amount of information that can be ‘packed into light’ “ 

    physdotorg
    phys.org

    1
    Data of the Rubik’s cube sent and received. Credit: Wits University

    The rise of big data and advances in information technology has serious implications for our ability to deliver sufficient bandwidth to meet the growing demand.

    Researchers at the University of the Witwatersrand in Johannesburg, South Africa, and the Council for Scientific and Industrial Research (CSIR) are looking at alternative sources that will be able to take over where traditional optical communications systems are likely to fail in future.

    In their latest research, published online today (10 June 2016) in the scientific journal, Scientific Reports, the team from South Africa and Tunisia demonstrate over 100 patterns of light used in an optical communication link, potentially increasing the bandwidth of communication systems by 100 times.

    The idea was conceived by Professor Andrew Forbes from Wits University, who led the collaboration. The key experiment was performed by Dr Carmelo Rosales-Guzman, a Research Fellow in the Structured Light group in the Wits School of Physics, and Dr Angela Dudley of the CSIR, an honorary academic at Wits.

    The first experiments on the topic were carried out by Abderrahmen Trichili of Sup’Com (Tunisia) as a visiting student to South Africa as part of an African Laser Centre funded research project. The other team members included Bienvenu Ndagano (Wits), Dr Amine Ben Salem (Sup’Com) and Professor Mourad Zghal (Sup’Com), all of who contributed significantly to the work.

    Bracing for the bandwidth ceiling

    Traditional optical communication systems modulate the amplitude, phase, polarisation, colour and frequency of the light that is transmitted. Yet despite these technologies, we are predicted to reach a bandwidth ceiling in the near future.

    2
    Dr. Carmelo Rosales-Guzman from Wits University. Credit: Wits University

    But light also has a “pattern” – the intensity distribution of the light, that is, how it looks on a camera or a screen.

    Since these patterns are unique, they can be used to encode information:

    pattern 1 = channel 1 or the letter A,
    pattern 2 = channel 2 or the letter B, and so on.

    What does this mean?

    That future bandwidth can be increased by precisely the number of patterns of light we are able to use.

    Ten patterns mean a 10x increase in existing bandwidth, as 10 new channels would emerge for data transfer.

    At the moment modern optical communication systems only use one pattern. This is due to technical hurdles in how to pack information into these patterns of light, and how to get the information back out again.

    How the research was done

    In this latest work [not available until paper is published], the team showed data transmission with over 100 patterns of light, exploiting three degrees of freedom in the process.

    They used digital holograms written to a small liquid crystal display (LCD) and showed that it is possible to have a hologram encoded with over 100 patterns in multiple colours.

    “This is the highest number of patterns created and detected on such a device to date, far exceeding the previous state-of-the-art,” says Forbes.

    One of the novel steps was to make the device ‘colour blind’, so the same holograms can be used to encode many wavelengths.

    According to Rosales-Guzman to make this work “100 holograms were combined into a single, complex hologram. Moreover, each sub-hologram was individually tailored to correct for any optical aberrations due to the colour difference, angular offset and so on”.

    What’s next?

    The next stage is to move out of the laboratory and demonstrate the technology in a real-world system.

    “We are presently working with a commercial entity to test in just such an environment,” says Forbes. The approach of the team could be used in both free-space and optical fibre networks.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 2:57 pm on June 8, 2016 Permalink | Reply
    Tags: , , patent new class of lasers, , Researchers invent   

    From phys.org: “Researchers invent, patent new class of lasers” 

    physdotorg
    phys.org

    June 8, 2016
    No writer credit found

    1
    Kristan Corwin, left, and Brian Washburn, both associate professors of physics at Kansas State University, have invented a new patented class of lasers. Credit: Kansas State University

    A new class of lasers developed by a team that included physics researchers at Kansas State University could help scientists measure distances to faraway targets, identify the presence of certain gases in the atmosphere and send images of the earth from space.

    These energy-efficient lasers also are portable, produce light at difficult-to-reach wavelengths and have the potential to scale to high-powered versions.

    The new lasers were invented by Brian Washburn and Kristan Corwin, both associate professors of physics at Kansas State University’s College of Arts & Sciences, along with Andrew Jones, a May 2012 doctoral graduate in physics, and Rajesh Kadel, a May 2014 doctoral graduate in physics. Other contributors include three University of New Mexico physics and astronomy researchers: Wolfgang Rudolf, a Regents professor and department chair, Vasudevan Nampoothiri, a research assistant professor, and Amarin Ratanavis, a doctoral student; and John Zavada, a Virginia-based optic and photonic physicist who brought them all together.

    The new lasers are fiber-based and use various molecular gases to produce light. They differ from traditional glass-tube lasers, which are large and bulky, and have mirrors to reflect the light. But the novel lasers use a hollow fiber with a honeycomb structure to hold gas and to guide light. This optical fiber is filled with a molecular gas, such as hydrogen cyanide or acetylene. Another laser excites the gas and causes a molecule of the excited gas to spontaneously emit light. Other molecules in the gas quickly follow suit, which results in laser light.

    “By putting the gas in a hollow core, we can have really high intensities of light without having to put such high amounts of power into the laser,” Corwin said. “If you had a glass tube of that size and put light in it, the light would escape through the sides. It’s actually the structure that makes it work.”

    The structure also allows for portability. In contrast to traditional lasers, which are fragile and cumbersome to move, the researchers’ more durable fiber laser is about the thickness of a single strand of hair and can wrap around itself for compact storage and transportation.

    “The smallness is nice,” Washburn said. “You can wrap up the coil like a string.”

    The invention process began when Zavada brought Washburn and Corwin, who already had expertise putting gas into hollow fibers, together with Rudolph and Nampoothiri, who were skilled in making optically pumped gas lasers.

    “We thought hard about how this would all work together, and after about a year and a half, we came up with this,” Corwin said.

    The inventors’ lasers use gas, which was the popular method before manufacturers moved to solid-state materials. For example, up until the mid-1990s, grocery store scanners were gas lasers, while present-day grocery scanners use solid-state lasers.

    “What we’ve done is use an old-school technology medium in a new-school package,” Washburn said.

    The researchers are continuing to study and improve the lasers using fibers from Fetah Benabid at Xlim in Limoges, France, with funding from the U.S. Air Force Office of Scientific Research and the U.S. Air Force Research Laboratory.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 12:09 pm on June 8, 2016 Permalink | Reply
    Tags: , , , Second layer of information in DNA confirmed   

    From phys.org: “Second layer of information in DNA confirmed” 

    physdotorg
    phys.org

    June 8, 2016
    Erik Arends

    1
    The rigid base-pair model is forced, using 28 constraints (indicated by red spheres), into a lefthanded superhelical path that mimics the DNA conformation in the nucleosome. Credit: Leiden Institute of Physics

    Leiden theoretical physicists have proven that DNA mechanics, in addition to genetic information in DNA, determines who we are. Helmut Schiessel and his group simulated many DNA sequences and found a correlation between mechanical cues and the way DNA is folded. They have published their results in PLoS One.

    When James Watson and Francis Crick identified the structure of DNA molecules in 1953, they revealed that DNA information determines who we are. The sequence of the letters G, A, T and C in the famous double helix determines what proteins are made ny our cells. If you have brown eyes, for example, this is because a series of letters in your DNA encodes for proteins that build brown eyes. Each cell contains the exact same letter sequence, and yet every organ behaves differently. How is this possible?

    Mechanical cues

    Since the mid 1980s, it has been hypothesized that there is a second layer of information on top of the genetic code consisting of DNA mechanical properties. Each of our cells contains two meters of DNA molecules, and these molecules need to be wrapped up tightly to fit inside a single cell. The way in which DNA is folded determines how the letters are read out, and therefore which proteins are actually made. In each organ, only relevant parts of the genetic information are read. The theory suggests that mechanical cues within the DNA structures determine how preferentially DNA folds.

    Simulation

    For the first time, Leiden physicist Helmut Schiessel and his research group provide strong evidence that this second layer of information indeed exists. With their computer code, they have simulated the folding of DNA strands with randomly assigned mechanical cues. It turns out that these cues indeed determine how the DNA molecule is folded into so-called nucleosomes. Schiessel found correlations between the mechanics and the actual folding structure in the genome of two organisms—baker’s yeast and fission yeast. This finding reveals evolutionary changes in DNA—mutations—that have two very different effects: The letter sequence encoding for a specific protein can change, or the mechanics of the DNA structure can change, resulting in different packaging and levels of DNA accessibility, and therefore differing frequency of production of that protein.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 7:51 am on June 7, 2016 Permalink | Reply
    Tags: , , , Scientists unlock X-Files DNA mystery   

    From phys.org- “The truth is out there: Scientists unlock X-Files DNA mystery” 

    physdotorg
    phys.org

    June 6, 2016

    1
    Branched DNA. Credit: Jon Sayers, University of Sheffield

    Scientists have unlocked a crucial part of the mystery as to how our DNA can replicate and repair itself – something which is essential for all life forms.

    The new research, conducted by leading scientists at the University of Sheffield, has revealed how branched DNA molecules are removed from the iconic double-helical structure -a process which scientists have been looking to unlock for over 20 years.

    Jon Sayers, Professor of Functional Genomics at the University of Sheffield and lead author of the study, said: “Branched DNA features in several episodes of the X-Files as Agent Scully suspects aliens inserted it in her blood.

    “In reality, far from being of alien origin, branched DNA is formed every day in our bodies. It happens every time our cells divide. These branches are essential intermediates formed during the process of copying our DNA.”

    The interdisciplinary team from the University’s Departments of Infection, Immunity and Cardiovascular Disease, and Molecular Biology and Biotechnology, captured never-before-seen snapshots of the molecular events in incredible detail. They show how Flap EndoNuclease enzymes (FENs) trim branched DNA molecules after cells have divided.

    The scientists found the FEN threads the free end of the branch through a hole in the enzyme before sliding along to the trunk where it acts like a pair of molecular secateurs, trimming the branch and restoring the iconic double-helix.

    The team made the discovery using the Diamond Light Source – the UK’s synchrotron which works like a giant microscope harnessing the power of electrons to produce bright X-ray light which scientists can use to study anything from fossils and jet engines to viruses and vaccines.

    Diamond Light Source U.K.
    Diamond Light Source U.K.

    Professor Sayers said: “The FENs analysed in the study are very similar to those used in diagnostic tests for genetic diseases, bacteria and viruses. Understanding how they work will help to engineer better and more reliable tests and tools for laboratory research and hospital diagnostics labs.

    “Because DNA replication is essential for all life forms, understanding how it works at a molecular level provides insight into one of the most basic cellular processes common to all life.

    “The enzymes that carry out this process are sometimes involved in cancer. They have been linked to tumour progression and mutation, so this discovery could pave the way for better diagnostics or new drugs.”

    He added: “Knowing how these enzymes work could aid development of new antimicrobial drugs that may one day be used to fight antibiotic resistant bacteria.”

    Results of the pioneering study are published [link below] today (June 6, 2016) in Nature Structural & Molecular Biology.

    Dr John Rafferty, from the University of Sheffield’s Department of Molecular Biology and Biotechnology and author on the study, said: “We can now see the details of how cells have evolved to tidy up after themselves as they copy their DNA, which reduces their risk of harmful mutations.

    “This sort of information is fundamental in helping us understand and maybe treat those cells where occasionally things do go wrong.”

    Explore further: DNA repair enzyme mapped in atomic detail

    More information: Direct observation of DNA threading in flap endonuclease complexes, Nature Structural & Molecular Biology, DOI: 10.1038/nsmb.3241

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 12:16 pm on May 25, 2016 Permalink | Reply
    Tags: , , , Slowly evolving superluminous supernova   

    From phys.org: “Astronomers discover an unusual, slowly evolving superluminous supernova” 

    physdotorg
    phys.org

    May 25, 2016
    Tomasz Nowakowski

    1
    Stacked iP1 PS1/MDS pre-explosion image of the field around PS1-14bj (left), compared to an i-band image from GMOS taken near peak (right). A faint host galaxy is clearly seen at the supernova position. In the GMOS image, which has significantly better seeing (0.4′′ FWHM, compared to 1.3′′ in the template), it appears that the host galaxy may have some structure or multiple components. Credit: Lunnan et al., 2016.

    A team of astronomers has found a hydrogen-poor superluminous supernova with exceptional properties. According to a research paper published online on May 17, on the arXiv pre-print server, the cosmic explosion, designated PS1-14bj, shows an exceptionally slow rise to maximum light and a very leisurely fade-out. It the longest rise time measured in a superluminous supernova to date.

    PS1-14bj was first detected in November 2013 by an international team of researchers led by Ragnhild Lunnan of the California Institute of Technology. The astronomers used the Pann-STARR, S1 telescope (PS1) on Mount Haleakala in Hawaii to find this supernova and employed a set of other telescopes [MMT, Gemini, Large Binocular, MDM 2.4 m
    Hiltner, Baade] worldwide to conduct follow-up observations of the object.

    Pann-STARRS1 interior
    Pann-STARRS1 interior

    MMT Telescope at the summit of Mount Hopkins near Tucson, Arizona, USA
    MMT Telescope at the summit of Mount Hopkins near Tucson, Arizona, USA

    Gemini/North telescope
    Gemini

    Large Binocular Telescope
    Large Binocular Telescope, Mount Graham, Arizona, USA

    PS1 is excellent at finding supernovae and other objects that change or move in the sky. PS1-14bj was found as part of a project carried out by PS1, called the Medium Deep Survey, that imaged the same fields of the sky every night to search for transient objects like supernovae.

    What drew the attention of the astronomers was that the newly discovered supernova was rising in brightness to maximum light much more slowly than usual.

    “PS1-14bj stood out in the PS1 data by rising in brightness much slower than a common supernova does, which is what initially prompted us to follow it up further,” Lunnan told Phys.org.

    Follow-up observations allowed the team to obtain spectra and additional optical images of PS1-14bj. It turned out that this supernova evolves very slowly as its rise time to maximum takes more than 120 days, and it also fades away very slowly (about 250 days). To put that in perspective, ordinary supernovae usually take a few weeks to rise to maximum light, while a typical superluminous supernova rise time might be 30 to 50 days.

    According to Lunnan, this slow evolution is similar to what is expected for a special kind of explosion mechanism called a pair-instability supernova, and PS1-14bj fits some of the theoretical expectations of what such an explosion would look like.

    However, it also has some properties that are very hard to explain in a pair-instability model. What puzzles the scientists is its unusual color evolution, with the color temperature rising prior to peak, and staying constant within uncertainties around 8,000-10,000 K through the peak and decline. The team speculates about how the color stays blue, indicating high temperatures, as the supernova fades away, rather than cooling.

    “This means that there is some energy source heating the supernova ejecta at very late times, and it’s unclear what that energy source is. One possibility is that there is material around the star, a shell of gas that got ejected from the star before it exploded, and as the supernova explosion runs into this the gas is heated by the collision,” Lunnan said.

    Other possible explanation offered by the scientists is that the supernova could be powered by a magnetar. It is a rapidly spinning neutron star with a strong magnetic field that was formed from the core of the star as the star went supernova, which could then also be heating the supernova ejecta to very late times.

    “Every time we discover something we haven’t seen before, it adds to our understanding. For example, PS1-14bj shows us that there exist superluminous supernovae that have the kind of broad, slow light curves that are predicted by pair-instability supernova models. Of course, discovering new things also tends to add to the list of things we don’t yet understand, but that is part of the fun of doing science,” Lunnan concluded.

    Since PS1-14bj has faded away, the team will now focus on the study of the host galaxy to determine what kind of star exploded. They hope to find out whether the star came from a very low metallicity galaxy or not.

    Science paper: PS1-14bj: A Hydrogen-Poor Superluminous Supernova With a Long Rise and Slow Decay, arxiv.org/abs/1605.05235

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 10:51 am on May 21, 2016 Permalink | Reply
    Tags: , , Electricity from seawater,   

    From phys.org: “Electricity from seawater: New method efficiently produces hydrogen peroxide for fuel cells” 

    physdotorg
    phys.org

    May 20, 2016
    Lisa Zyga

    1
    Credit: Mr. William Folsom, NOAA, NMFS

    Scientists have used sunlight to turn seawater (H2O) into hydrogen peroxide (H2O2), which can then be used in fuel cells to generate electricity. It is the first photocatalytic method of H2O2 production that achieves a high enough efficiency so that the H2O2 can be used in a fuel cell.

    The researchers, led by Shunichi Fukuzumi at Osaka University, have published a paper* on the new method of the photocatalytic production of hydrogen peroxide in a recent issue of Nature Communications.

    “The most earth-abundant resource, seawater, is utilized to produce a solar fuel that is H2O2,” Fukuzumi told Phys.org.

    The biggest advantage of using liquid H2O2 instead of gaseous hydrogen (H2), as most fuel cells today use, is that the liquid form is much easier to store at high densities. Typically, H2 gas must be either highly compressed, or in certain cases, cooled to its liquid state at cryogenic temperatures. In contrast, liquid H2O2 can be stored and transported at high densities much more easily and safely.

    The problem is that that, until now, there has been no efficient photocatalytic method of producing liquid H2O2. (There are ways to produce H2O2 that don’t use sunlight, but they require so much energy that they are not practical for use in a method whose goal is to produce energy.)

    In the new study, the researchers developed a new photoelectrochemical cell, which is basically a solar cell that produces H2O2. When sunlight illuminates the photocatalyst, the photocatalyst absorbs photons and uses the energy to initiate chemical reactions (seawater oxidation and the reduction of O2) in a way that ultimately produces H2O2.

    After illuminating the cell for 24 hours, the concentration of H2O2 in the seawater reached about 48 mM, which greatly exceeds previous reported values of about 2 mM in pure water. Investigating the reason for this big difference, the researchers found that the negatively charged chlorine in seawater is mainly responsible for enhancing the photocatalytic activity and yielding the higher concentration.

    Overall, the system has a total solar-to-electricity efficiency of 0.28%. (The photocatalytic production of H2O2 from seawater has an efficiency of 0.55%, and the fuel cell has an efficiency of 50%.)

    Although the total efficiency compares favorably to that of some other solar-to-electricity sources, such as switchgrass (0.2%), it is still much lower than the efficiency of conventional solar cells. The researchers expect that the efficiency can be improved in the future by using better materials in the photoelectrochemical cell, and they also plan to find methods to reduce the cost of production.

    “In the future, we plan to work on developing a method for the low-cost, large-scale production of H2O2 from seawater,” Fukuzumi said. “This may replace the current high-cost production of H2O2 from H2 (from mainly natural gas) and O2.”

    Science paper:
    Seawater usable for production and consumption of hydrogen peroxide as a solar fuel

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 1:15 pm on May 17, 2016 Permalink | Reply
    Tags: , , Moon and Mars veggies' grow in Dutch greenhouse,   

    From phys.org: “Out of this world: ‘Moon and Mars veggies’ grow in Dutch greenhouse” 

    physdotorg
    phys.org

    May 17, 2016
    Sophie Mignon

    1
    Researcher Wieger Wamelink inspects the plants grown in Mars and moon soil simulant in a research facility at the University of Wageningen

    Establishing a human colony on the Moon and travelling to Mars has been the stuff of dreams since the dawn of the space age.

    But these visions face many hurdles. How can humans survive for months or years in the ultra-hostile environment of space? What, for instance, will they eat?

    Agricultural researchers at a Dutch university say they are taking the first steps towards providing an answer.

    They are growing vegetables in soils similar to those found on the Moon and Mars, looking for ways of helping space pioneers grow their own crops.

    “When people go to the Moon and Mars they also have to eat, and it’s easiest for them to grow their own food,” said Wieger Wamelink, surrounded by several dozen plants in a special greenhouse at Wageningen, an agricultural university in central Netherlands.

    “We wanted to use real Martian and lunar soil,” to see if plants would actually grow in it, Wamelink told AFP.

    Of course, getting real lunar and Martian potting soil is an impossible ask. But an Internet search revealed an unlikely supplier: NASA.

    The US space agency makes ground similar to that on the Moon from sand found in an Arizona desert, while Mars’ crimson “soil” is scooped from a volcano in Hawaii, Wamelink told AFP.

    The first experiments started in 2013 after Wageningen received an order of 100 kilograms (220 pounds) of NASA’s imitation “space soil”—at a hefty price of 2,000 euros ($2,285).

    Wamelink stuck tomatoes, peas, cress and other plants in pots containing the simulated soil… and crossed his fingers.

    To work in this soil “was very special. Nobody, not even NASA, could tell us what would happen,” even just by simply adding water, he said.

    The imitation ground at first was a little “reluctant” to absorb water, but soon turned out to be good potting soil.

    Like the actor Matt Damon in the science fiction movie “The Martian”, Wamelink watched with amazement as his “space veggies” grew bigger day-by-day.

    “Especially in the Martian soil, plants were growing very fast and very good. They even started to flower, something that we never anticipated,” Wamelink said. The 50-day experiment was written up* in the science journal PLOS One in August 2014.

    2
    NASA plans a human trip to Mars within the next 10 to 15 years.

    Safe for humans?

    An essential question however remains whether these unusual vegetables are safe to eat.

    Martian and lunar soil, including NASA’s own imitation, may contain heavy metals that are harmless to plants but could prove deadly to humans.

    Wamelink has come up with a possible solution.

    If analyses show that the vegetables contain arsenic, mercury or iron making them unfit for human consumption, the soil can be purified by growing other plant species such as violets which absorb the poisons.

    Wamelink concedes that the experiment has a drawback—it is being conducted in non-sterile conditions on Earth where only the nutrient quality of the soil is being assessed.

    “There’s much more to test,” Wamelink admitted.

    Extremely cold temperatures—dropping to minus 62 degrees Celsius (minus 79 Fahrenheit) on Mars—as well as a lack of oxygen means that lunar or Martian vegetables and fruit could only be grown in a closed and controlled environment.

    The facility would have to be pressurised to normal atmospheric conditions on Earth, heated and lit, and protected from cosmic radiation, which damages plant DNA.

    That points to a “space greenhouse”—a type of container, buried underground and kitted out with solar panels and LED lighting. Water should be no problem as it is found as ice on both the Moon and Mars, said Wamelink.

    Other questions that need answers include the presence of friendly bacteria to help plant growth and what happens to plants that grow in low gravity.

    ‘Long way to go’

    NASA plans a human trip to Mars within the next 10 to 15 years or so but similar plans are also being pursued by billionaire Elon Musk and the Dutch company Mars One, tentatively aiming to set up human colonies on the Red Planet.

    Technology and the know-how to keep astronauts alive on Mars still has a long way to go said Christophe Lasseur, a European Space Agency (ESA) “Life Support” expert, who deals with metabolic aspects of space travel.

    Lasseur believed Wamelink’s research of growing plants in space soils “is not a priority”.

    He said other requirements for space survival like the proper infrastructure to grow similar vegetables in laboratories was far more essential to provide “maximum reliability” for future teams.

    “We must regard a plant as a piece of technology and understand exactly what happens to it first. All chemical, microbiological and physiological aspects (of plants in extraterrestrial conditions) needs to be understood and mapped… We cannot take risks.”

    *Science paper:
    Can Plants Grow on Mars and the Moon: A Growth Experiment on Mars and Moon Soil Simulants

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 3:42 pm on May 16, 2016 Permalink | Reply
    Tags: , , Novel 'liquid wire' material inspired by spiders' capture silk,   

    From phys.org: “Scientists create novel ‘liquid wire’ material inspired by spiders’ capture silk” 

    physdotorg
    phys.org

    May 16, 2016

    1
    Hybrid material inspired from spiders. Credit: University of Oxford

    Why doesn’t a spider’s web sag in the wind or catapult flies back out like a trampoline? The answer, according to new research by an international team of scientists, lies in the physics behind a ‘hybrid’ material produced by spiders for their webs.

    Pulling on a sticky thread in a garden spider’s orb web and letting it snap back reveals that the thread never sags but always stays taut—even when stretched to many times its original length. This is because any loose thread is immediately spooled inside the tiny droplets of watery glue that coat and surround the core gossamer fibres of the web’s capture spiral.

    This phenomenon is described* in the journal PNAS by scientists from the University of Oxford, UK and the Université Pierre et Marie Curie, Paris, France.

    The researchers studied the details of this ‘liquid wire’ technique in spiders’ webs and used it to create composite fibres in the laboratory which, just like the spider’s capture silk, extend like a solid and compress like a liquid. These novel insights may lead to new bio-inspired technology.

    Professor Fritz Vollrath of the Oxford Silk Group in the Department of Zoology at Oxford University said: ‘The thousands of tiny droplets of glue that cover the capture spiral of the spider’s orb web do much more than make the silk sticky and catch the fly. Surprisingly, each drop packs enough punch in its watery skins to reel in loose bits of thread. And this winching behaviour is used to excellent effect to keep the threads tight at all times, as we can all observe and test in the webs in our gardens.’


    Access mp4 video here .

    The novel properties observed and analysed by the scientists rely on a subtle balance between fibre elasticity and droplet surface tension. Importantly, the team was also able to recreate this technique in the laboratory using oil droplets on a plastic filament. And this artificial system behaved just like the spider’s natural winch silk, with spools of filament reeling and unreeling inside the oil droplets as the thread extended and contracted.

    Dr Hervé Elettro, the first author and a doctoral researcher at Institut Jean Le Rond D’Alembert, Université Pierre et Marie Curie, Paris, said: ‘Spider silk has been known to be an extraordinary material for around 40 years, but it continues to amaze us. While the web is simply a high-tech trap from the spider’s point of view, its properties have a huge amount to offer the worlds of materials, engineering and medicine.

    ‘Our bio-inspired hybrid threads could be manufactured from virtually any components. These new insights could lead to a wide range of applications, such as microfabrication of complex structures, reversible micro-motors, or self-tensioned stretchable systems.’

    *Science paper: In-drop capillary spooling of spider capture thread inspires hybrid fibers with mixed solid–liquid mechanical properties, PNAS

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 9:15 am on May 5, 2016 Permalink | Reply
    Tags: , , , Scientists detect unexpected drop in the magnetic field of an X-ray pulsar   

    From phys.org: “Scientists detect unexpected drop in the magnetic field of an X-ray pulsar” 

    physdotorg
    phys.org

    May 5, 2016
    Tomasz Nowakowski

    1
    The pulsar pictured here, which resides in the Messier 82 galaxy 12 million light-years away, sends out X-ray beams that pass Earth every 1.37 seconds. Scientists studying this object with NuSTAR originally thought it was a massive black hole, but its X-ray pulse revealed its true pulsar identity. Credit: NASA/JPL-Caltech

    Messier 82 Cigar starburst galaxy
    Messier 82 Cigar starburst galaxy

    NASA/NuSTAR
    NASA/NuSTAR

    A team of scientists has recently presented evidence of an unexpected drop in the observed magnetic field of an accreting pulsar designated V0332+53. This downturn, observed after the pulsar underwent a bright, three-month-long X-ray outburst, could yield important information on how the accreted mass settling on the surface of a neutron star affects its magnetic field. The findings are detailed in a paper* published online on Apr. 26 in the arXiv journal.

    V0332+53 is an accreting pulsar emitting X-ray radiation, with a spin period of 4.4 seconds. It orbits an early type companion star in an eccentric orbit of about 34 days. Significantly, this pulsar shows sporadic giant X-ray outbursts lasting several weeks, followed by years-long intervals of dormancy.

    These X-ray outburst were observed in 1989, between November 2004 and February 2005, and between June and September 2015. The latest outburst drew the attention of a team of researchers, led by Giancarlo Cusumano of the Institute of Space Astrophysics and Cosmic Physics in Palermo, Italy. Using the Burst Alert Telescope (BAT) and the X-Ray Telescope (XRT), both mounted on NASA’s Swift spacecraft, the astronomers were able to observe the pulsar in soft X-ray and high-energy bands.

    NASA/SWIFT Telescope
    NASA/SWIFT Telescope

    By studying the results, the team detected a noteworthy drop in the observed magnetic field between the onset and the end of the outburst.

    “The comparison of the XRT profiles in the soft X-rays provides a hint against the hypothesis of a geometrical beam variation. If, on the other hand, the line-forming region is the same at equal luminosities, the observed difference in the cyclotron energy corresponds to a difference in the magnetic field of about 1.7 ×1011 G,” the researchers wrote in the paper.

    The findings could be crucial for our understanding of matter accretion processes in neutron stars and could provide new insights on pulsars’ X-ray outburst events. According to the research, the magnetic field of neutron star drives the accreting matter along its field lines towards the magnetic polar caps, forming an accretion column, where matter is followed up by radiative processes that produce X-rays.

    Notably, the drop in the magnetic field, as described in the latest paper, wasn’t observed after previous outbursts. The researchers found out that although the total mass accreted at the end of the 2004-2005 and the 2015 outburst is similar, during the 2004-2005 event, a higher luminosity was reached earlier. They also concluded that decay of the magnetic field is not directly proportional to the total accreted mass.

    Moreover, the scientists hypothesize that the cause of the significant decay of the magnetic field through accretion observed at V0332+53could be due to “diamagnetic screening.”

    “In this hypothesis, the accreting plasma builds up to form a magnetically confined mound, where the gas pressure balances the magnetic stresses. This would produce, as an overall effect, a distortion of the field lines observed as a decrease of the field component along the accretion column,” the paper reads.

    However, as the team noted, the lack of coverage in the first ten days of the outburst doesn’t allow them to confirm this theory.

    More information: Topic Model Based Multi-Label Classification from the Crowd, arXiv:1604.00783 [cs.LG] arxiv.org/abs/1604.0783

    *Science paper:
    Topic Model Based Multi-Label Classification from the Crowd

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: