|
Mobile version
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Physicists make iron invisible to X-rays Ars Technica Share    
A research team at Deutsches Elektronen-Synchrotron in Germany has induced transparency in an Fe-57 sample by using an X-ray laser to balance the absorption of photons by the nuclei with corresponding emission, which makes it appear as though the material is nearly absent. The experimental technique, called electromagnetically induced transparency, was recently reported in Nature. The experiment's success depends on nuclear transitions being available at X-ray wavelengths and the correct placement of atomic layers in a resonant cavity. Also in the experiment the he X-ray photons are slowed to a small fraction of their usual speed, and the result opens up the possibility of extending quantum optics in the nuclear regime and the X-ray region of the EM spectrum. More
Unusual 'collapsing' iron superconductor sets record for its class NIST Center for Neutron Research Share
A team from the National Institute of Standards and Technology and the University of Maryland has reported in Physical Review B an iron-based superconductor that operates at the highest known temperature for a material in its class. Iron-based superconductors, which were discovered only about four years ago, are a hot research topic, in part because they are more amenable to commercial applications than copper-based superconductors, which are more difficult to make and are frequently brittle. This new material, which contains iron, calcium, arsenic, and praseodymium (Z=59) atoms, has a Tc of 47 K. More
Why salt clusters form on basement walls American Physical Society Share
Salt deposits on walls and other structures can lead to serious damage, but researchers don't fully understand how they form. Now a French team reporting in Physical Review Letters has performed experiments and computer simulations of salt crystallization on porous structures and explains why the crystals form in discrete bunches, rather than uniformly coating the surface. The new understanding may help in the conservation of old buildings and art pieces. More Possible model of uterus contractions during child birth American Physical Society Share
In the heart there are specialized pacemaker cells that organize electromechanical activity. In the uterus there may be no such pacemaker cells. Rather, uterine smooth muscle contractions can arise without centralized coordination, and the musculature seems to be a disordered system of electrically coupled excitable and passive cells. Physiological and histological evidence suggests that the electrical coupling between cells increases during the gestation period, culminating in strongly coupled, electrically active cells during labor. A model reported in Physical Review Letters shows how the uterus goes from localized activity initially to system-wide coherent excitations just before delivery. More
New neutrino detection points to rare stellar fusion Physics World Share
The Borexino Collaboration, working in the underground neutrino detector at Italy's National Institute of Nuclear Physics at Gran Sasso, has captured neutrinos with a distinct energy of 1.44 MeV. These neutrinos are indicative of proton-electron-proton (pep) fusion reactions that are rare in stellar interiors. The proton-proton pathway is the dominant fusion reaction in our sun. Reported in Physical Review Letters, this is the first direct evidence of pep reactions taking place in the sun, and the observed flux matches well with the predictions of astrophysicists' "standard solar model." More
'Quantum microphone' captures extremely weak sound: A step towards quantum acoustics Nanowerk Share
Physicists at Chalmers University in Sweden have fabricated a single electron transistor, i.e., a transistor where the current passes one electron at a time, and they have used it to detect surface acoustic waves. Their experiments, reported in Nature Physics, were done with classical waves. But since the wave displacements were so small (half the diameter of a proton), the researchers propose that they can detect single phonons. The researchers call their device a "quantum microphone." Actually detecting a single phonon still has some technical challenges. Recent results coupling photons and phonons or using a superconducting "qubit" may solve some of these challenges. So single phonon acoustics may join its photonic brother very soon. More Accretion of asteroids by black hole may explain X-ray flares at the center of Milky Way msnbc.com Share
The once-per-day X-ray flares from Sagittarius A* may be caused by asteroids approaching the event horizon of the black hole at the center of our galaxy. Astrophysicists suspect there is a massive swarm of asteroids circling the black hole. As they pass to within about 100 million miles of the black hole, still outside of the event horizon, they would succumb to its attractive gravitational force and eventually be broken up. As the broken bits flow through hot gases pouring into the black hole, they would vaporize, producing bursts of X-ray radiation. This theory is written up in a paper appearing in the Monthly Notices of the Royal Astronomical Society. More
Astronomy team discovers nearby dwarf galaxy UCLA Newsroom Share
A team led by University of California, Los Angeles, research astronomer Michael Rich has used a specialized wide-field telescope to discover a previously unknown companion to the nearby galaxy NGC 4449, which is some 12.5 million light years from Earth. The discovery is reported in Nature. The newly found dwarf galaxy, dubbed NGC 4449B, had remained undetected because it is more than 10 times fainter than the natural brightness of the night sky and some 1,000 times fainter than our own Milky Way galaxy. The discovery team included UCLA finance professor Francis Longstaff, an amateur astronomer, who led the development of the specialty telescope, which places the CCD camera at what is known as the "prime" focus, in front of the light-collecting mirror. More
Quantum dot used for targeted activation of neurons Optical Society of America Share
Researchers at the University of Wisconsin, Madison, have used nanometer sized quantum dots to stimulate individual neural cells. Reported in Biomedical Optics Express, the researchers grew cell populations on films of quantum dots, which covered on average just one cell. The electrical behavior of individual cells was then measured as they were exposed to flashes of light of various wavelengths. The light photo-excited electrons in the quantum dots, creating electric fields that triggered spiking in the cells. These quantum dots enable finer examination of neural activity since they probe a single cell at a time, and the photo-stimulation of nerve cells can be monitored in response to distinct wavelengths of light. More
President Obama announces education initiatives at White House science fair NY Times Share
President Obama for a second time converted the White House public rooms into a science fair on Tuesday, and announced new federal and private-sector initiatives to encourage "a nation of tinkerers and dreamers" in so-called STEM education in science, technology, engineering and math. According to a White House summary, in his annual federal budget request next week, Mr. Obama will seek to dedicate $80 million for the Education Department to a $100 million competition — more than $20 million will come from corporations and foundations led by Carnegie Corporation — to support programs to prepare teachers in science, technology, engineering and math, including programs allowing students to simultaneously earn a degree in their subject and a teaching certificate. The administration had previously set a goal of 100,000 additional math and science teachers and one million more graduates over the next decade. More Federal agencies announce FY-13 budget briefings AAAS Share
The various federal S&T agencies will hold budget briefings throughout the day, starting with the OSTP briefing from 1:30 - 2:30pm. The NSF briefing will start at 3:30pm, and NASA's at 2:00pm. The DOE briefing will be from 1:30-4:00pm. While live seating is available, each briefing will be webcast. Please see the AAAS R & D Budget and Policy Program's website for the webcasts' links and for detailed budget analyses. More  Obama's budget would cut Mars program, solar system exploration The Washington Post Share
The budget coming on Feb. 13 from the Obama administration will send the NASA division that launches rovers to Mars and probes to Jupiter crashing back to Earth. Scientists briefed on the proposed budget said that the president's plan drops funding for planetary science at NASA from $1.5 billion this year to $1.2 billion next year, with further cuts continuing through 2017. It would eat at NASA's Mars exploration program, which, after two high-profile failures in 1999, has successfully sent three probes into Martian orbit and landed three more on the planet's surface. Former NASS Associate Administrator for Science, Ed Weiler, says he quit NASA over cuts to Mars program. More If you want to win the game, you must join in Nature Share
Rees Kassen an associate professor at the University of Ottawa, and chair of the Partnership Group for Science and Engineering and a young scientist of the World Economic Forum, offers his suggestions to scientists to engage in policy and the political process. First, improve the lines of communication. Opportunities for scientists to carry out fellowships in a political environment, such as the Congressional Fellows Program run by the American Association for the Advancement of Science, are a start in this direction. Second, we need scientists to stand for election to public office. Third, scientists need to seek opportunities to engage with politicians directly. More Francois Arago: The most interesting physicist in the world Skulls in the Stars Share
If you asked to describe what a "typical" physicist looks and acts like most people would paint wouldn't be terribly flattering, and would conform to rather negative stereotypes. One physicist, however, blows away the stereotypes perhaps more than any other. The French physicist François Arago (1786-1853) lived a lifetime's worth of danger, adventure and intrigue in just his first 23 years of life — and he would go on to make crucial discoveries in optical science as well as become an important politician of his time. More  Increase your options for graduate or REU program admissions NSBP Share
The NSBP GradApps and REUApps services are open to all students and allows them to upload all the elements of an admissions application, including academic and work history, transcripts, letters of recommendation and a personal statement. Graduate and REU programs can subscribe to these databases to increase the programs' applicant pool, while at the same time allowing students can put their credentials in front of more programs than to which they would otherwise apply. More
National Society of Black Physicists jobs board postings NSBP Share
Research in Sustainable Energy for sub-Saharan Africa Yale University Center for Research on Interface Structure and Phenomena Postdoctoral Fellow Iowa State University REU Science Undergraduate Laboratory Internship Notre Dame Physics REU Program Iowa State University REU Nonequilibrium Materials Research Experience for Undergraduates Iowa State University REU National Science Foundation Engineering Research Center for Biorenewable Chemicals Iowa State University REU Biogeosciences Research Experiences for Undergraduates Iowa State University REU Wind Energy Science, Engineering and Policy Iowa State University REU Microscale Sensing Actuation and Imaging Jack E. Crow Postdoctoral Fellowship at National High Magnetic Field Laboratory Iowa State University REU Interdisciplinary Research and Education Emerging Interface Technologies Wiess Instructorship in Physics and Astronomy University of Northern Iowa REU in Hyperspectral Imaging REU Opportunities in Astronomy at the University of Wyoming REU Program at Nevis Labs, Columbia University REU Program in Computational Sensing and Medical Robotics (CS&MR) William & Mary (NASA Langley, Jefferson Lab) Physics Department REU University of Florida Materials Physics Research Experience for Undgraduates Undergraduate Research in Computational Astrophysics (URCA) Rutgers, the State University of New Jersey RiSE (Research in Science and Engineering) Summer Program Advice for graduate students Inside Higher Education Steven Stearns offers some insight and advice for graduate students. Know thyself and know thy advisor. More More advice for graduate students Inside Higher Education So much comes down to good writing skills. Steven Stearns offers some tips on how to write well and write strategically. More Overcoming the imposter syndrome About.com At one time or another nearly every graduate student and new faculty member wonders about his or her competence. This is a common fear often referred to as the impostor syndrome. The impostor syndrome runs rampant in academia — and women are especially prone to it. How do you get over the impostor syndrome? Easier said than done. More Ready. Set. Go. Transitioning from college to graduate school GradSchools.com Compared to your undergraduate education, graduate school is faster paced. Professors expect a lot of work to be done, and there's a lot less hand-holding. More
Latest research from Semiconductor Science and Technology IOP Journal Share
Tin oxide and indium oxide nanowire transport characteristics: influence of oxygen concentration during synthesis
Low interface trapped charge density in MBE in situ grown Si3N4 cubic GaN MIS structures A TCAD-based modeling of GaN/InGaN/Si solar cells Synthesis and characterization of Cd1−xCoxS thin films prepared using the spray pyrolysis technique Barrier height and interface characteristics of Au/Mn5Ge3/Ge (1 1 1) Schottky contacts for spin injection Solve semiconductor anagrams at Twitter http://www.twitter.com/@SSTscience. Look for the hashtag #SSTanagram. More Latest research from Physics and Chemistry of the Earth Physics and Chemistry of the Earth Share
Arsenic and heavy metals in native plants at tailings impoundments in Queretaro, Mexico
A generic framework for tsunami evacuation planning Urban geophysics A review of volcanic ash aggregation Molecular hydrogen: An abundant energy source for bacterial activity in nuclear waste repositories Modeling the viscoplastic and damage behavior in deep argillaceous rocks Metallic corrosion processes reactivation sustained by iron-reducing bacteria: Implication on long-term stability of protective layers Numerical simulation of the time-dependent deformation behavior of claystone rock mass at the Tournemire site with 2-D and 3-D models Investigating the electrical conductivity of volcanic ash and its effect on HV power systems More |
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||
