Month: August 2019

Current theories cant explain observed spin segregation

first_img(PhysOrg.com) — Experiments with quantum systems sometimes yield surprising results. This is exactly what happened when John Thomas, a researcher at Duke University in Durham, North Carolina found out when he and his post doc, Du, and his students Luo and Clancy, attempted to study a trapped cloud of Fermi atoms all initially in the same quantum superposition of spin-up and spin-down states. They expected all of the atoms to move uniformly back and forth in the trap. Instead, the atoms moved in a way that not predicted using existing theory. Research reveals exotic quantum states in double-layer graphene Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.center_img The results of their experiment can be found in Physical Review Letters: “Observation of Anomalous Spin Segregation in a Trapped Fermi Gas.”“It was nuts,” Thomas tells PhysOrg.com. “The atoms in this prepared gas didn’t behave at all as one would expect. We thought we’d be doing something simple, and now we’re attempting to understand something we didn’t expect.”Thomas explains that particles known as fermions (which make up the Fermi gas) act in a way that is very similar to electrons: When they are put in the same quantum spin state, or q-bit, they tend to avoid each other. This is useful in a variety of applications related to quantum computing because this prevents particles from colliding with each other, destroying information. As a result, fermions are being considered in the development of quantum memory, since they would (theoretically) avoid each other and remain coherent.Thomas and his team wanted create a collection of fermions in identical quantum spin states by applying a radio frequency field. “We set up an experiment in which we used a very cold gas of lithium-6, all initially in the spin-up state,” he says. “We trapped these fermions in a laser beam, a sort of bowl made of light. We put about 100,000 atoms in this optical bowl and attempted to use a radiofrequency (rf) field to prepare them all in the same state of super position, which is 50 percent spin-up and 50 percent spin-down.”At first, it looked as though all was as it should be. Thomas and his colleagues took images of the atoms just after applying the rf field, and found that immediately following the change, the fermions behaved as expected. “But, after tenths of a second,” Thomas continues, “we saw that things were different. The spin-downs were moving to the edges of the bowl, and the spin-ups were moving to the center, remaining in this pattern for several seconds.” Thomas and his students began considering explanations for the phenomenon. “We know that this segregation does not arise from ordinary forces between the atoms, which are far too small to explain the observed effects. We believe that the segregation arises from the formation of a spin-wave, but the size of the effect that we observe is much larger and the timescale over which it occurs is much longer than predicted by existing spin-wave theory.”On a practical level, it seems as though the idea of using a collection of fermions for quantum memory will have to be revisited. At the fundamental physics level, a lot more study is needed. “Ultimately we’ll do more on this,” Thomas says, “because it’s something that we want to understand. But we are waiting for help from theorists. We’d like to have theoretical feedback so that there are other facets to test.”Copyright 2007 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Citation: Current theories can’t explain observed spin segregation (2008, October 16) retrieved 18 August 2019 from https://phys.org/news/2008-10-current-theories-segregation.htmllast_img read more

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Physicists search for new physics in primordial quantum fluctuations

first_img Theoretical physicists Mark G. Jackson of the University of Paris-7 Diderot in Paris, France, and Koenraad Schalm of the University of Leiden in Leiden, The Netherlands, have published their study on these possible signatures of new physics in the inflationary power spectrum in a recent issue of Physical Review Letters.Primordial fluctuationsThe physicists’ work focuses on the Planck scale, the ultra-high-energy conditions at the time of the Big Bang. Although the universe at this point was almost completely homogeneous, the violent dynamics of inflation produced tiny inhomogeneities from the quantum vacuum. Virtual pairs of particles from the quantum vacuum began popping in and out of existence, some of which could absorb energy and become real. Physicists think that all matter today, from galaxies to living things, originated from these primordial quantum fluctuations. But physicists are even more interested in this era for what it may reveal about quantum gravity.“The Planck scale is the energy at which the two major theories in physics – gravity and quantum field theory – necessarily combine,” Jackson and Schalm told PhysOrg.com. “The resultant theory of quantum gravity is one of the major open problems in physics, though by now there is a lot of evidence that string theory is the answer. In an ideal world one would wish to test this experimentally. Unfortunately, this Planck energy scale is laughably beyond the reach of standard experiments such as particle accelerators: it would be like reaching out your hand to touch the Moon. Fortunately, Nature did once perform an ultra-high-energy experiment possibly capable of probing the Planck scale: the Big Bang. Now while we can’t re-do the Big Bang, we can witness its consequences.” This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. One of the most instrumental methods of detecting the Big Bang’s consequences is measuring the CMB radiation – the faint, mostly microwave-frequency background glow that permeates the entire universe. Leftover from the recombination epoch during the early universe when atoms were just beginning to form, the CMB is almost completely uniform, except for some small temperature fluctuations in the radiation that scientists first detected in the early ’90s. These temperature fluctuations stem from the primordial quantum fluctuations that occurred during inflation.The CMB data has enabled scientists to calculate the spectrum of the wavelengths of the primordial quantum fluctuations, providing some of the earliest experimental data of anything. Although the spectrum calculated from observations closely matches the spectrum calculated from current theories, the continuing advance of high-precision experiments could provide an opportunity to observe something new. “The details of quantum gravity could be encoded in the fluctuations of the quantum field responsible for the rapid inflation of the Universe near the Big Bang,” the physicists wrote. “The primary diagnostic – the power spectrum of these quantum field fluctuations – could contain a wealth of information about high-energy physics taking place during this inflationary period.”A closer lookBy computing universal generic corrections to the inflationary power spectrum, Jackson and Schalm hope to provide a starting point for analyzing a wide variety of new physics theories. The universal corrections are independent of the precise details of any quantum gravity theory or other unknown Planck-scale physics, but future experiments could help narrow down these possibilities. In particular, the upcoming experiments Planck and CMBPol/Inflation Probe, which aim to measure CMB temperature fluctuations with unprecedented sensitivity, might have a shot at detecting the small corrections. If future experiments did observe these corrections, the findings could potentially reveal new physics on the Planck scale.“We computed exactly what to look for in terms of specific features of the power spectrum,” Jackson and Schalm wrote. “Our hook was that the dominant feature should only depend on the ratio of the scale of inflation to the Planck scale. The significance of our study is that one can now analyze the observational effects of physics theories at energy scales which would have been impossible to study previously. These include quantum gravity theories, such as superstring theory. Complementing the theoretical tools that we have developed is the vast amount of precision cosmological data soon available from the Planck satellite, for example. Researchers will be able to calculate experimental predictions for some model of high-energy physics. If the data turns out to look nothing like the prediction, the model can be ruled out. If it’s similar, one can refine the model.”The physicists describe the corrections as a map, similar to a map a passenger might use to navigate the Paris metro, but in this case the map is to show physicists how to analyze any new physics model they develop. In a sense, it’s similar to how the passenger can use a map to get to any destination on the metro line, even if the passenger doesn’t yet know where they’re going.“People had studied a few individual models of high-energy modifications during inflation, but the analysis tools were completely specific to that particular model,” Jackson and Schalm wrote. “If one tweaked the model even a little bit, they’d no longer have any idea how to study it. What we’ve done is to give a map of how to analyze any model. Just take the model, follow some few simple rules and you can calculate anything you please. We give a few simple examples of how to do this, but the tools are not specific to those models. This is why we claim that we have developed the model-independent set of tools to analyze high-energy physics.”The physicists hope that the new map will prove useful in the future, even if they don’t know exactly where they’re headed, or what type of high-energy physics may have existed during inflation.“If experiments indeed find some features in the power spectrum,” they said, “we may not yet understand precisely what physics causes these features, but it will demonstrate that there is some new very high-energy modification to inflation, and this may be a result of quantum gravity.” Citation: Physicists search for new physics in primordial quantum fluctuations (2012, March 26) retrieved 18 August 2019 from https://phys.org/news/2012-03-physicists-physics-primordial-quantum-fluctuations.html Copyright 2012 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. (PhysOrg.com) — Inflation, the brief period that occurred less than a second after the Big Bang, is nearly as difficult to fathom as the Big Bang itself. Physicists calculate that inflation lasted for just a tiny fraction of a second, yet during this time the Universe grew in size by a factor of 1078. Also during this time, a very important thing occurred: fluctuations in the quantum vacuum appeared, which later resulted in the temperature fluctuations in the cosmic microwave background (CMB) that in turn produced large-scale structures such as galaxies. But in a new study, physicists now think that their understanding of the features of primordial quantum fluctuations – also called the inflationary power spectrum – may require a few small corrections due to currently unknown physics. These new corrections could allow scientists to search for experimental evidence to test a variety of quantum gravity theories, including string theory.center_img Physicists propose test for loop quantum gravity More information: Mark G. Jackson and Koenraad Schalm. “Model Independent Signatures of New Physics in the Inflationary Power Spectrum.” PRL 108, 111301 (2012). DOI: 10.1103/PhysRevLett.108.111301 The evolution of the universe from the Big Bang to the present. Quantum fluctuations that arise during inflation develop into the inhomogeneities that lead to the formation of stars and galaxies. Image credit: NASA Explore furtherlast_img read more

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IDair has a fingerprint scanner from standoff distance

first_imgResearchers are exploring better designs in biometrics to meet business and government demands for reliable identification and verification tools. Out of the many biometric technologies that continue to be works in progress, fingerprinting continues to be an accepted technique. Fingerprint-matching has been a mainstay in law enforcement but businesses now look toward fingerprinting systems for security management and access control. Other solutions such as flashing photo ID cards or licenses to confirm true identities of people passing in and out the doors have not been entirely reliable. Fingerprints replace keys Explore further More information: idairco.com/products This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.center_img © 2012 Phys.Org A new startup, IDair, wants to make the difference. Its new fingerprint scanner system can read fingerprints from up to six meters away. The person waves hand to sensor for identification verification–no stops at checkpoints asking for a ID card; no fumbling around for lost keycards. The machine is described as a touchless scanner. The fingerprint can be photographically captured with enough detail to match against a database. A selling point is that fingerprints are collected at a standoff distance so there is no need for people to touch a scanner pad, avoiding problems in accuracy compromised from dirt, grime, or oil on the finger.The scenario is simple, in that the company places the scanner device on the door; the person sends prints to the system, which takes a snapshot when triggered and uses pattern recognition, edge detection and sharpening to scan the fingerprint, which is then compared to the database. The system is described as close to the way satellites process ground images.Joel Burcham, CEO of IDair, Clemson-trained with a PhD in physics, talked about his product plans recently at the HudsonAlpha Institute for Biotechnology. in Huntsville, Alabama, where he has a company office. Actually, IDair is a spin-off of Advanced Optical Systems (AOS), which focuses on government customers. While AOS takes on its government customers IDair is grooming commercial outlets for interest in biometric technologies. The company hopes to make a difference with its expertise in touchless sensors for easier identification and verification. Currently, a 24-hour fitness center chain is beta-testing the IDair system. The chain wants to tackle access-key sharing by friends or roommates. Burcham also has a longer range vision for making his technology suitable in retail applications.Meanwhile, the IDair basic product priced under $2,000 processes only one finger’s print. In biometrics, it is agreed that just one finger’s print is good for certain applications but more may be required for increased levels of accuracy. IDair hopes to add sensors to the mix such as for face recognition and iris scanning, in a more comprehensive biometric system.The company will also need to step over nothing-is-safe security qualms, actually privacy issues, among those who warn of the risk of any digital fingerprint database being leaked. Citation: IDair has a fingerprint scanner from standoff distance (2012, June 24) retrieved 18 August 2019 from https://phys.org/news/2012-06-idair-fingerprint-scanner-standoff-distance.htmllast_img read more

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Study finds women prefer perfumes that mimic their immune system cells

first_img(Phys.org)—A research team in Germany has found that when given the choice, women prefer the smell of perfume that has chemicals in it that mimic the smell of their own immune proteins. In their study published in the Proceedings of the Royal Society B, the researchers found that female volunteers applying perfumes preferred those with a synthetic ingredient similar to major histocompatibility complexes (MHCs) found in their own cells. Journal information: Proceedings of the Royal Society B Credit: Wikipedia (public domain) Why bad immunity genes survive: Study implicates arms race between genes and germs Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.center_img © 2013 Phys.org Citation: Study finds women prefer perfumes that mimic their immune system cells (2013, January 24) retrieved 18 August 2019 from https://phys.org/news/2013-01-women-perfumes-mimic-immune-cells.html Virtually every cell in the human body has MHC, it’s a protein the body uses to help keep track of which cells belong in the body, and which are invasive. Cells that have the protein are not attacked by the immune system. But MHCs, according to this new research, also have an odor that may play a part in mate selection.Prior research has shown that women prefer the scent of a man that has MHCs that are similar to their own, but not too similar. In this new effort, the researchers looked into the possibility that women use perfume as a means of enhancing their own MHCs, thereby, assisting in choosing a mate that will help provide offspring with a strong immune system.To test this idea, the researchers enlisted the aid of 22 female volunteers who were asked to shower, wear a non odor producing t-shirt and to apply different perfumes to their underarms – each was created to smell identical to the others, the difference was in the synthetic MHCs that were added. The study went on for two nights and afterwards, each of the volunteers were asked to report which perfumes they preferred. The synthetic MHCs added to the perfumes were created to mimic those found in an average sample of people, except for one – that one was intended to recreate the volunteer’s actual MHCs.In analyzing the preferences given by the volunteers, the researchers found that they consistently (smokers and those with colds were excluded) chose the perfume that had the synthetic MHC in it that mimicked the one produced naturally in their own bodies. This, the researchers claim, shows that while women prefer others to smell of MHCs that are different from theirs, they prefer the smell of their own MHCs on themselves. To bolster this assertion, they asked another group of women to sniff different perfumes with different MHCs in them while undergoing an fMRI exam. In so doing, they noted that only the perfume with the MHC that mimicked the person’s own proteins, caused the middle frontal cortex to become active.Taken together, the researchers propose that the evidence indicates that the real purpose of perfume is likely to enhance the MHC odor of their own bodies to aid in attracting a mate that is most suitable from an immunological perspective. More information: Major histocompatibility complex peptide ligands as olfactory cues in human body odour assessment, Published online January 23, 2013 doi: 10.1098/rspb.2012.2889AbstractIn many animal species, social communication and mate choice are influenced by cues encoded by the major histocompatibility complex (MHC). The mechanism by which the MHC influences sexual selection is a matter of intense debate. In mice, peptide ligands of MHC molecules activate subsets of vomeronasal and olfactory sensory neurons and influence social memory formation; in sticklebacks, such peptides predictably modify the outcome of mate choice. Here, we examine whether this evolutionarily conserved mechanism of interindividual communication extends to humans. In psychometric tests, volunteers recognized the supplementation of their body odour by MHC peptides and preferred ‘self’ to ‘non-self’ ligands when asked to decide whether the modified odour smelled ‘like themselves’ or ‘like their favourite perfume’. Functional magnetic resonance imaging indicated that ‘self’-peptides specifically activated a region in the right middle frontal cortex. Our results suggest that despite the absence of a vomeronasal organ, humans have the ability to detect and evaluate MHC peptides in body odour. This may provide a basis for the sensory evaluation of potential partners during human mate choice.last_img read more

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New species of crocodile newt identified in Vietnam

first_imgTylototriton ziegleri. Credit: Tao Thien Nguyen New findings on immune system in amphibians © 2013 Phys.org (Phys.org) —A new species of crocodile newt has been identified by a team of Japanese researchers—based on study of a specimen held at Japan’s National Museum of Nature and Science in Tokyo and field study in Vietnam. The original specimen, the team writes in their article describing the find in the journal Current Herpetology, was found in the mountainous northern provinces of Vietnam’s Ha Giang and Cao Bang. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. More information: A New Species of Tylototriton from Northern Vietnam (Amphibia: Urodela: Salamandridae), Current Herpetology 32(1):34-49. 2013 www.bioone.org/doi/abs/10.5358/hsj.32.34AbstractA new species of the salamandrid genus Tylototriton is described from Ha Giang and Cao Bang provinces, northern Vietnam, based on molecular and morphological data. The new species differs morphologically from all known congeners in the combination of blackish body coloration; medium-sized body; distinctly rough skin; tubercular vertebral ridge; knob-like rib nodules; large eye; and low, narrow tail. The distribution pattern of species of Tylototriton in Vietnam is briefly discussed.via Mongabay Citation: New species of crocodile newt identified in Vietnam (2013, March 21) retrieved 18 August 2019 from https://phys.org/news/2013-03-species-crocodile-newt-vietnam.html Explore further A newt is a member of the salamander family (Salamandridae)—genus Tylototriton—though, not all salamanders are considered newts—one of their main differentiating characteristics is rougher skin. They are aquatic and have been found to live in North America, Asia and Europe. Crocodile newts are so named due to their similar appearance to crocodiles—they’re much smaller of course, generally only stretching to a few inches long.The new specimen was found at the museum in Japan, and its curator contacted Kanto Nishikawa, one of the researchers involved in the study. Initial observations indicated nothing out of the ordinary, but after closer inspection, the team realized that its morphology didn’t conform to any known species. They subsequently performed genetic analysis which confirmed the newt as a new species: Tylototriton ziegleri— Ziegler’s crocodile newt—after the prominent German researcher Thomas Ziegler, who has contributed greatly to the study and conservation of amphibians and reptiles in Vietnam.The newt is deep black all over save for its orange tipped feet—average male length is estimated to be two to two and a half inches long—the females are slightly longer. Its body sports horny crocodile-looking scales along its length and its head resembles that of a horned toad. All told, the newt offers a very striking appearance.Crocodile newts are prized by collectors and as a result, 3 of the 10 known species are considered endangered or near extinction, including this new discovery. Their range is limited and as humans move in, changing the terrain, their chances of survival are reduced. For this reason, the researchers suggest that the Ziegler’s crocodile newt be added to the list of protected species as soon as possible to help it survive.last_img read more

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Researchers improve accuracy of synthetic clock

first_img Scientists have noted the high precision that some living cells demonstrate in keeping track of time, such as those that are part of the circadian clock, and have tried to duplicate the process. Sixteen years ago, Michael Elowitz and Stanislas Leibler developed what is now known as the repressilator—a synthetic oscillating genetic circuit. Their results demonstrated that it was possible for genetic circuits to be designed and built in the lab. The resulting circuit functioned, but was noisy, and therefore much less accurate than natural cell clocks. In this new effort, the researchers improved several of the design steps of the repressilator, each greatly reducing the amount of noise, and in so doing, increased the precision.The repressilator was made using repressor proteins that would bind to DNA sequences that were adjacent to a gene to be targeted for inhibition. Three repressors were created such that each one represented the expression of the next cycle—when the protein in one repressor increased, it caused a decrease in the expression of the second, which in turn caused an increase in expression of the third, and so on, resulting in oscillations—the actions were monitored by reporters. Unfortunately, each was bothered by random fluctuations known as noise. To reduce the noise, the researchers integrated the reporters into the repressilator, engineered the repressor proteins to degrade in order to reduce the number of copies made, and increased the binding threshold between one of the repressors and the DNA sequence.In testing their improvements, the researchers found they had reduced the standard deviation of the period length from 35 percent to just 14 percent, which Gao and Elowitz describe as extraordinary precision—good enough to allow large numbers of cells to remain in sync. More information: Laurent Potvin-Trottier et al. Synchronous long-term oscillations in a synthetic gene circuit, Nature (2016). DOI: 10.1038/nature19841AbstractSynthetically engineered genetic circuits can perform a wide variety of tasks but are generally less accurate than natural systems. Here we revisit the first synthetic genetic oscillator, the repressilator, and modify it using principles from stochastic chemistry in single cells. Specifically, we sought to reduce error propagation and information losses, not by adding control loops, but by simply removing existing features. We show that this modification created highly regular and robust oscillations. Furthermore, some streamlined circuits kept 14 generation periods over a range of growth conditions and kept phase for hundreds of generations in single cells, allowing cells in flasks and colonies to oscillate synchronously without any coupling between them. Our results suggest that even the simplest synthetic genetic networks can achieve a precision that rivals natural systems, and emphasize the importance of noise analyses for circuit design in synthetic biology. Journal information: Nature This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Researchers improve accuracy of synthetic clock (2016, October 13) retrieved 18 August 2019 from https://phys.org/news/2016-10-accuracy-synthetic-clock.html (Phys.org)—A team of researchers with Harvard University and the University of Cambridge has successfully improved the accuracy of a synthetic clock known as a repressilator. In their paper published in the journal Nature, the team describes the steps they took to reduce the amount of noise in the biological system and how well it worked. Xiaojing Gao and Michael Elowitz with the California Institute of Technology offer a News & Views piece on the work done by the team and explain how their results could improve understanding of natural gene circuits.center_img Explore further © 2016 Phys.org A 5-mm diameter colony of cells with the triple reporter repressilator (LPT117) reveals tree-like ring patterns in fluorescent protein levels. The average YFP intensity is reported for the slice in the white rectangle. The decrease in RFP levels towards the edge of the colony is probably due to different response to stationary phase of its promoter. Credit: (c) Nature (2016). DOI: 10.1038/nature19841 Scientists find cells rhythmically regulate their geneslast_img read more

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New dwarf satellite galaxy of Messier 83 found

first_img Hubble peers at a distinctly disorganized dwarf galaxy (Phys.org)—Astronomers have found a new dwarf satellite of Messier 83 (M83, also known as the Southern Pinwheel Galaxy) located some 85,000 light years from its host. This satellite galaxy was designated dw1335-29 and could be an irregular or a transition dwarf. The findings were presented in a paper published Nov. 30 on arXiv.org. Citation: New dwarf satellite galaxy of Messier 83 found (2016, December 5) retrieved 18 August 2019 from https://phys.org/news/2016-12-dwarf-satellite-galaxy-messier.html © 2016 Phys.org Messier 83 is one of the closest and brightest barred spiral galaxies. It is located about 15 million light years away in the constellation Hydra. Finding new satellites of galaxies beyond the Local Group such as Messier 83 could provide essential insights on galaxy formation in a cosmological context.In 2015, the detection of 16 dwarf galaxy candidates near Messier 83 was announced. However, it remained unclear which of them were satellites of this galaxy. To confirm this, follow-up observations were needed to estimate reliable distances.Now, a team of astronomers led by Andreia Carrillo of the University of Michigan used images from the Galaxy Halos, Outer disks, Substructure, Thick disks and Star clusters (GHOSTS) survey provided by the Hubble Space Telescope (HST) and data from the Very Large Telescope’s (VLT) Visible MultiObject Spectrograph (VIMOS) to confirm that one of the 16 candidates is indeed a satellite of Messier 83.”Using a combination of VIMOS ground-based data and HST resolved stellar imaging, we have confirmed that the dwarf candidate dw1335-29 is indeed a satellite of M83,” the researchers wrote in the paper.The team explained that they detected an overdensity of primarily red giant branch-colored stars with a modest overdensity of blue stars at the position of dw1335-29, confirming it to be a nearby dwarf galaxy. Moreover, it permitted them to estimate its distance from Messier 83 and allowed surface brightness profile measurements.According to the research, dw1335-29 has a half light radius of approximately 2,140 light years and an ellipticity of 0.4. The scientists found that this dwarf is dominated by an old metal-poor stellar population and its metallicity [Fe/H] is -1.3. The team also noted that it is the faintest confirmed member of the Messier 83 group.Finally, dw1335-29 has been classified as a dwarf irregular or transition dwarf due to its irregular shape and the likely presence of a star-forming region. “Owing to dw1335-29’s somewhat irregular shape and possible young stars, we classify this galaxy as a dwarf irregular or transition dwarf. This is curious, as with a projected distance of 26 kpc from M83, dw1335-29 is expected to lack recent star formation,” the paper reads.The researchers assume that perhaps dw1335-29 has a larger M83-centric distance and is coincidentally projected close to its host, or perhaps the galaxy lacks a sufficiently dense hot gas envelope to quench star formation in its satellites. They hope that a comprehensive census of Messier 83 satellites and their star formation properties would help to resolve this issue.”Further study of M83’s dwarf population will reveal if star formation in its satellites is commonplace (suggesting a lack of a hot gas envelope for M83 that would quench star formation) or rare (suggesting that dw1335-29 has a larger M83-centric distance, and is fortuitously projected to small radii),” the team concluded. A deep photographic image of M83 taken using the UK Schmidt Telescope by Malin & Hadley (1997, figure reproduced with permission) where the white scale bar corresponds to 30 arcmin. The northern stream appears not to be associated with dw1335-29, circled in red. Credit: Carrillo et al., 2016. Explore further More information: Characterizing dw1335-29, a recently discovered dwarf satellite of M83, arXiv:1611.10361 [astro-ph.GA] arxiv.org/abs/1611.10361AbstractThe number, distribution, and properties of dwarf satellites are crucial probes of the physics of galaxy formation at low masses and the response of satellite galaxies to the tidal and gas dynamical effects of their more massive parent.To make progress, it is necessary to augment and solidify the census of dwarf satellites of galaxies outside the Local Group. M”uller et al. (2015) presented 16 dwarf galaxy candidates near M83, but lacking reliable distances, it is unclear which candidates are M83 satellites. Using red giant branch stars from the HST/GHOSTS survey in conjunction with ground-based images from VLT/VIMOS, we confirm that one of the candidates, dw1335-29— with a projected distance of 26 kpc from M83 and a distance modulus of (m−M)0=28.5+0.3−0.1—is a satellite of M83. We estimate an absolute magnitude MV=−10.1±0.4, an ellipticity of 0.40+0.14−0.22, a half light radius of 656+121−170 pc, and [Fe/H] = −1.3+0.3−0.4. Owing to dw1335-29’s somewhat irregular shape and possible young stars, we classify this galaxy as a dwarf irregular or transition dwarf. This is curious, as with a projected distance of 26 kpc from M83, dw1335-29 is expected to lack recent star formation. Further study of M83’s dwarf population will reveal if star formation in its satellites is commonplace (suggesting a lack of a hot gas envelope for M83 that would quench star formation) or rare (suggesting that dw1335-29 has a larger M83-centric distance, and is fortuitously projected to small radii). This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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Tuning in to the melody

first_imgThe 10th annual edition of the classical music festival SaMaPa (Sopori Academy of Music And Performing Arts)  Sangeet Sammelan is being organised in the Capital. The three-day long festival is a calendar event of Delhi and attracts connoisseurs of music from various parts of the country and abroad. The festival also features a painting and photography exhibition by the artistes of J and K and Delhi. SaMaPa Sangeet Sammelan is a gateway for the young musicians with exceptional talent getting their first stage in a prestigious festival along with senior legendary maestros of the country. The festival kicked off on 21 November. Also Read – ‘Playing Jojo was emotionally exhausting’The opening day of the festival  saw performances by – Swar-laya Samwad (Panch Tatva) – Sameer Bhalerao, Anjani Mishra, Nitin Sharma (Vocal) and Manoj Mishra, Deepak Sahai, Sachin Sharma (Tabla) with Pt. Vijay Shanker Mishra, Abhay Rustum Sopori (Santoor) and Rekha Nadgauda, Aditi Nadgauda Panse with Kirti Kala Mandir dance troupe (Kathak dance ).The second day featured Ajay Prasanna and Sugato Bhaduri on flute and mandolin, Dhananjay Hegde (vocal) and Pt. Debu Chaudhuri and Prateek Chaudhuri on sitar.  Also Read – Leslie doing new comedy special with NetflixThe festival will end today at the musical note of sitar and cello recitals by Shubhendra Rao and Saskia Rao De Haas. It will also feature Kaivalya Kumar (Vocal) and recitals of Pt. Bhajan Sopori  on santoor.The festival will also be featuring other maestros like – Ustad Akram Khan, Athar Hussain, Durjay Bhaumik, Mithilesh Jha, Ustad Rafiuddin Sabri, Shailendra Mishra, Subash Kanti Das (Tabla), Rishi Shankar Upadhyay (Pakhawaj), Ghanshyam Sisodia (Sarangi), Damodar Lal Ghose, Paromita Mukherjee, Vinay Mishra (Harmonium) and others. SaMaPa is a cultural movement translating from a deep rooted vision of its Chairman, Pandit Bhajan Sopori and the tireless efforts of the members of Board in creating a unique, unbiased and empowering national level platform for presentation, propagation, and teaching of traditional music and performing arts for the artistes and the young talents. It is acclaimed as a cultural bridge of the State of Jammu and Kashmir with rest of the country and to have created a new generation of music connoisseurs. SaMaPa widens its horizon into the general masses by creating the right platform for better appreciation and understanding of the traditional music and its technicalities, and enabling them to utilize the power of music in leading a more balanced life, as well as exploring opportunities with music as means to their employment. It recognises the contribution of several artistes, leaders, officials and individual personalities for their tireless efforts in propagating and keeping the traditional system of music alive.When: On till 23 NovemberWhere: Kamani Auditorium, Copernicus MargTiming: 6 pm onwardlast_img read more

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Zico lambasts referee for denying FC Goa penalty

Zico said he failed to understand why the same person, who had given a controversial penalty against his team in the group stage against the same opponents, was asked to officiate the important match. Goa lost the match 2-4 on penalties to bow out of the competition at the Jawaharlal Nehru stadium on Wednesday.“We had many chances during the game, like the penalty that was not called by the referee. I didn’t understand why this referee was called, since he was the referee who gave a penalty to Atletico against us in Kolkata. Such mistakes cannot be made in games like these. In the last match, Bruno Pinheiro was given a red card and on Wednesday we were denied a penalty,” Zico said. Also Read – Khel Ratna for Deepa and Bajrang, Arjuna for JadejaAtletico defender Arnab Mondal brought down Goa’s Brazilian recruit Andre Santos inside the penalty box in the 56th minute, evoking a strong shout from the Goa bench but it was swiftly turned down. Iramatov was also criticised earlier for awarding Atletico a penalty in a group match between the two teams in Kolkata Dec 10 that helped the home team draw 1-1 and qualify for the play-off. Zico also pointed out that Atletico won because of their superior marking skills which did not give the Goans much place to play open football.“Atletico marked very well and they tried to neutralise us. We get very few chances, which we failed to capitalise. Kolkata lost a lot of their power without striker Fikru. So they changed their strategy and took the game to the penalty and won,” he said. Zico added despite the disappointment, he has spoken to the management and would return to coach Goa for the next two years. read more

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Bengal becomes SGST surplus

first_imgKolkata: The Centre has congratulated Bengal government for its success in registering a revenue surplus and rapidly bringing down the revenue gap in the State Goods and Services Tax (GST).In a tweet in this connection on Saturday, Chief Minister Mamata Banerjee stated: “You will be happy to know that Government of India has congratulated West Bengal for not only bringing down rapidly the revenue gap in State GST, but also registering a revenue surplus in March, 2018.” Also Read – Heavy rain hits traffic, flightsComparing the state’s performance with that of the country as a whole, she maintained: “The revenue gap in Bengal, which was 33.4% in August, 2017 has registered a surplus of 3% by March, 2018. The performance of the state has been far better than that of the country as a whole. Where Bengal achieved a surplus of 3% in March, 2018, the country as a whole registered a revenue deficit of 17.9% in March, 2018. My best wishes to all. I thought of sharing this with all of you.” Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedIn a letter to state Chief Secretary Malay De, the Union Finance Secretary Hasmukh Adhia stated that “…The overall revenue gap in SGST collection for the whole country in July was 28.3 percent which has come down to 17.9 percent in March. However, there have been spikes in between in the revenue gap in the month of November, December and February… As far as West Bengal is concerned, the revenue gap has come down… The revenue shortfall in West Bengal has been coming down steadily but there seems to have been a spike of a major gain in March where suddenly your revenue deficit has now become revenue surplus. I would like to congratulate West Bengal for such a performance…” Mamata Banerjee had voiced her concerns regarding the hurried implementation of the GST by the Modi government.last_img read more

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