WorldWideScience

Sample records for early universe gamma

  1. The early universe

    International Nuclear Information System (INIS)

    Steigman, G.

    1989-01-01

    The author discusses the physics of the early universe: the production and survival of relics from the big bang. The author comments on relic WIMPs as the dark matter in the universe. The remainder of this discussion is devoted to a review of the status of the only predictions from the early evolution of the universe that are accessible to astronomical observation: primordial nucleosynthesis

  2. Bulk viscous cosmology in early Universe

    Indian Academy of Sciences (India)

    The effect of bulk viscosity on the early evolution of Universe for a spatially homogeneous and isotropic Robertson-Walker model is considered. Einstein's field equations are solved by using `gamma-law' equation of state = ( - 1)ρ, where the adiabatic parameter gamma () depends on the scale factor of the model.

  3. Mapping the early Universe

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    From its unique vantage point 900 kilometres above the earth's surface, NASA's Cosmic Background Explorer (COBE) satellite has a privileged view of cosmic background radiation - the remnants of the early (radiation-dominated) Universe which followed the Big Bang some ten Gigayears ago, and possibly some subsequent history. In this way astroparticle physicists get a first peek at the quantum cosmology which moulded the infant Universe

  4. Mapping the early Universe

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1991-06-15

    From its unique vantage point 900 kilometres above the earth's surface, NASA's Cosmic Background Explorer (COBE) satellite has a privileged view of cosmic background radiation - the remnants of the early (radiation-dominated) Universe which followed the Big Bang some ten Gigayears ago, and possibly some subsequent history. In this way astroparticle physicists get a first peek at the quantum cosmology which moulded the infant Universe.

  5. The Gamma-ray Universe through Fermi

    Science.gov (United States)

    Thompson, David J.

    2012-01-01

    Gamma rays, the most powerful form of light, reveal extreme conditions in the Universe. The Fermi Gamma-ray Space Telescope and its smaller cousin AGILE have been exploring the gamma-ray sky for several years, enabling a search for powerful transients like gamma-ray bursts, novae, solar flares, and flaring active galactic nuclei, as well as long-term studies including pulsars, binary systems, supernova remnants, and searches for predicted sources of gamma rays such as dark matter annihilation. Some results include a stringent limit on Lorentz invariance derived from a gamma-ray burst, unexpected gamma-ray variability from the Crab Nebula, a huge ga.nuna-ray structure associated with the center of our galaxy, surprising behavior from some gamma-ray binary systems, and a possible constraint on some WIMP models for dark matter.

  6. Gamma ray bursts of black hole universe

    Science.gov (United States)

    Zhang, T. X.

    2015-07-01

    Slightly modifying the standard big bang theory, Zhang recently developed a new cosmological model called black hole universe, which has only a single postulate but is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain existing observations of the universe. In the previous studies, we have explained the origin, structure, evolution, expansion, cosmic microwave background radiation, quasar, and acceleration of black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This study investigates gamma ray bursts of black hole universe and provides an alternative explanation for the energy and spectrum measurements of gamma ray bursts according to the black hole universe model. The results indicate that gamma ray bursts can be understood as emissions of dynamic star-like black holes. A black hole, when it accretes its star or merges with another black hole, becomes dynamic. A dynamic black hole has a broken event horizon and thus cannot hold the inside hot (or high-frequency) blackbody radiation, which flows or leaks out and produces a GRB. A star when it collapses into its core black hole produces a long GRB and releases the gravitational potential energy of the star as gamma rays. A black hole that merges with another black hole produces a short GRB and releases a part of their blackbody radiation as gamma rays. The amount of energy obtained from the emissions of dynamic star-like black holes are consistent with the measurements of energy from GRBs. The GRB energy spectra derived from this new emission mechanism are also consistent with the measurements.

  7. Cosmology and the early universe

    CERN Document Server

    Di Bari, Pasquale

    2018-01-01

    This book discusses cosmology from both an observational and a strong theoretical perspective. The first part focuses on gravitation, notably the expansion of the universe and determination of cosmological parameters, before moving onto the main emphasis of the book, the physics of the early universe, and the connections between cosmological models and particle physics. Readers will gain a comprehensive account of cosmology and the latest observational results, without requiring prior knowledge of relativistic theories, making the text ideal for students.

  8. Galaxies in the Early Universe

    DEFF Research Database (Denmark)

    Krogager, Jens-Kristian

    Understanding how galaxies evolved from the early Universe through cosmic time is a fundamental part of modern astrophysics. In order to study this evolution it is important to sample the galaxies at various times in a consistent way through time. In regular luminosity selected samples, our...

  9. Physics of the early universe

    International Nuclear Information System (INIS)

    Klinkhamer, F.R.

    1983-01-01

    In this thesis, the author has assembled his papers on elementary particle physics which are of importance for studying cosmology viz. the physics of the early universe. A rather detailed introduction reviewing basic principles and current trends in the relation particle physics/cosmology precedes the papers. (Auth.)

  10. Shocks in the Early Universe.

    Science.gov (United States)

    Pen, Ue-Li; Turok, Neil

    2016-09-23

    We point out a surprising consequence of the usually assumed initial conditions for cosmological perturbations. Namely, a spectrum of Gaussian, linear, adiabatic, scalar, growing mode perturbations not only creates acoustic oscillations of the kind observed on very large scales today, it also leads to the production of shocks in the radiation fluid of the very early Universe. Shocks cause departures from local thermal equilibrium as well as create vorticity and gravitational waves. For a scale-invariant spectrum and standard model physics, shocks form for temperatures 1  GeVUniverse as early as 10^{-30}  sec after the big bang.

  11. Physics of the early universe

    International Nuclear Information System (INIS)

    Brandenberger, R.H.

    1987-01-01

    When studying the evolution of the very early universe it is necessary to use a description of matter which is appropriate at very high energies, namely in terms of quantum fields. In such models there may be a period during which the ratio of pressure and energy density is - 1, an equation of state which leads to an exponential expansion of the universe (inflation). There may also arise stable topological defects similar to vortex lines in condensed matter physics. These defects (cosmic strings) form seeds about which gas can accrete to form galaxies and clusters of galaxies. The author reviews inflation and cosmic strings, emphasizing their role in generating the energy density perturbations which are required in order to explain the existence of structures in the universe

  12. Cosmology and the early universe

    Science.gov (United States)

    Joshi, Abhigna

    2017-01-01

    In the beginning the universe was in a hot dense state nearly 13.8 billion years ago. The thermal history of the universe was traced back to an era when the temperature was about 1012K. At this early time, the universe was filled with particles-mostly photons and leptons- whose interactions are hopefully weak enough to allow this medium to be treated as a more or less ideal gas. However, if we look back a little further, into the first 0.0001 second of cosmic history when the temperature was above 1012K. At such temperatures, there will be present in thermal equilibrium copious numbers of strongly interacting particles-mostly masons and baryons-with a mean interparticle distance less than a Compton wavelength. These particles will be in a state of continual mutual interaction, and cannot reasonably be expected to obey any simple equation of state. The inflationary epoch lasted from 10-36seconds after the Big Bang to sometime between 10-33and 10-32seconds. Matter and energy created in this time. Right after that space expanded exponentially with enormous rate of 74.3 +/-2.1Km per second per Mpc. Undergraduate student and researcher of the string theory, quantum gravity, cosmology and quantum biology.

  13. On a chaotic early universe

    International Nuclear Information System (INIS)

    Tomita, Kenji.

    1974-11-01

    The theories regarding the origin of galaxies and elements are reviewed in this paper, and the assumptions made for these theories are discussed. It has been assumed that the universe has always been isotropic and homogeneous from the beginning of cosmic expansion. At the stage of very high density that any local irregularities such as galaxies cannot exist, the admissible deviation in this case from the mean value is only the statistical or quantum fluctuation of matter density, spatial curvature or their growth. It should be considered that the chemical composition of matters at the earliest stage consisted of most fundamental particles. However, if the fluctuation of matter density is statistical, the present values are too small. As for the origin of elements, it depends strongly on the period when cosmic radiation appeared. The final mass ratios of elements are given from the present baryon mass density, and are in agreement with observed values. The assumption of hot universe seems good. However, the time-independent ratio of photon number to baryon number is hardly understood. It is reasonable to assume for the early universe an inhomogeneous model whose space-time curvature is of turbulent character, according to weak cosmological principle. The inhomogeneous models to be considered are weakly non-linear perturbation theory, anti-Newtonian approximation and post anti-Newtonian approximation. Smoothing-out process, the origin of cosmic microwave radiation, the origin of galaxies and the origin of chemical elements are discussed. (Kato, T.)

  14. Gamma ray lines from a universal extra dimension

    Energy Technology Data Exchange (ETDEWEB)

    Bertone, Gianfranco; Jackson, C. B.; Shaughnessy, Gabe; Tait, Tim M.P.; Vallinotto, Alberto

    2012-03-01

    Indirect Dark Matter searches are based on the observation of secondary particles produced by the annihilation or decay of Dark Matter. Among them, gamma-rays are perhaps the most promising messengers, as they do not suffer deflection or absorption on Galactic scales, so their observation would directly reveal the position and the energy spectrum of the emitting source. Here, we study the detailed gamma-ray energy spectrum of Kaluza--Klein Dark Matter in a theory with 5 Universal Extra Dimensions. We focus in particular on the two body annihilation of Dark Matter particles into a photon and another particle, which produces monochromatic photons, resulting in a line in the energy spectrum of gamma rays. Previous calculations in the context of the five dimensional UED model have computed the line signal from annihilations into \\gamma \\gamma, but we extend these results to include \\gamma Z and \\gamma H final states. We find that these spectral lines are subdominant compared to the predicted \\gamma \\gamma signal, but they would be important as follow-up signals in the event of the observation of the \\gamma \\gamma line, in order to distinguish the 5d UED model from other theoretical scenarios.

  15. Gamma ray astronomy and search for antimatter in the universe

    International Nuclear Information System (INIS)

    Schoenfelder, V.

    1989-01-01

    Gamma ray astronomy provides a powerful tool for searching antimatter in the universe; it probably provides the only means to determine, if the universe has baryon symmetry. Presently existing gamma-ray observations can be interpreted without postulating the existence of antimatter. However, the measurements are not precise enough to definitely exclude the possibility of its existence. The search for antimatter belongs to one of the main scientific objectives of the Gamma Ray Observatory GRO of NASA, which will be launched in 1990 by the Space Shuttle. (orig.)

  16. Observing the very early universe

    CERN Document Server

    Steinhardt, Paul Joseph

    1995-01-01

    Cosmology is entering an historic epoch in which a dazzling array of new observations will decisively test our theories of the origin and evolution of the Universe. Many of the theoretical proposals have profound implications for our understanding of high-energy physics. This lecture series will review some of the leading ideas, especially the inflationary model of the universe, and explain the astrophysical and cosmological observations anticipated for the next decade that will be critical in determining their validity.

  17. Peculiarities of the early Universe (Universes) birth and positron annihilation

    International Nuclear Information System (INIS)

    Svetlov-Prokop'ev, E.P.

    2003-01-01

    Works on the problem of quantum birth of the Universe are reviewed. Possible peculiarities of electron-positron annihilation at the early stages of the Universe (s) birth in connection with black holes are considered. Possible concept of Eternity is discussed. (author)

  18. WMAP - A Glimpse of the Early Universe

    Science.gov (United States)

    Wollack, Edward

    2009-01-01

    The early Universe was incredibly hot, dense, and homogeneous. A powerful probe of this time is provided by the relic radiation which we refer to today as the Cosmic Microwave Background (CMB). Images produced from this light contain the earliest glimpse of the Universe after the "Big Bang" and the signature of the evolution of its contents. By exploiting these clues, precise constraints on the age, mass density, and geometry of the early Universe can be derived. The history of this intriguing cosmological detective story will be reviewed. Recent results from NASA's Wilkinson Microwave Anisotropy Probe (WMAP) will be presented.

  19. Gamma-Ray Bursts The Brightest Explosions in the Universe

    CERN Document Server

    Vedrenne, Gilbert

    2009-01-01

    Since their discovery was first announced in 1973, gamma-ray bursts (GRBs) have been among the most fascination objects in the universe. While the initial mystery has gone, the fascination continues, sustained by the close connection linking GRBs with some of the most fundamental topics in modern astrophysics and cosmology. Both authors have been active in GRB observations for over two decades and have produced an outstanding account on both the history and the perspectives of GRB research.

  20. The Toy model: Understanding the early universe

    Science.gov (United States)

    Fisher, Peter H.; Price, Richard H.

    2018-04-01

    In many branches of science, progress is being made by taking advantage of insights from other branches of science. Cosmology, the structure and evolution of the universe, is certainly an area that is currently beset by problems in understanding. We show here that the scientific insights from the studies of early childhood development, in particular, those of Piaget, give a new way of looking at the early universe. This new approach can not only be invaluable in undergraduate teaching, but can even be the basis of semi-quantitative predictions.

  1. Sterile neutrinos in the early universe

    Energy Technology Data Exchange (ETDEWEB)

    Malaney, R.A. (Lawrence Livermore National Lab., CA (USA)); Fuller, G.M. (California Univ., San Diego, La Jolla, CA (USA). Dept. of Physics)

    1990-11-14

    We discuss the role played by right-handed sterile neutrinos in the early universe. We show how well known {sup 4}He constraint on the number of relativistic degrees of freedom at early times limits the equilibration of the right handed neutrino sea with the background plasma. We discuss how this allows interesting constraints to be placed on neutrino properties. In particular, a new limit on the Dirac mass of the neutrino is presented. 12 refs.

  2. The Transient High Energy Sky and Early Universe Surveyor

    Science.gov (United States)

    O'Brien, P. T.

    2016-04-01

    The Transient High Energy Sky and Early Universe Surveyor is a mission which will be proposed for the ESA M5 call. THESEUS will address multiple components in the Early Universe ESA Cosmic Vision theme:4.1 Early Universe,4.2 The Universe taking shape, and4.3 The evolving violent Universe.THESEUS aims at vastly increasing the discovery space of the high energy transient phenomena over the entire cosmic history. This is achieved via a unique payload providing an unprecedented combination of: (i) wide and deep sky monitoring in a broad energy band(0.3 keV-20 MeV; (ii) focusing capabilities in the soft X-ray band granting large grasp and high angular resolution; and (iii) on board near-IR capabilities for immediate transient identification and first redshift estimate.The THESEUS payload consists of: (i) the Soft X--ray Imager (SXI), a set of Lobster Eye (0.3--6 keV) telescopes with CCD detectors covering a total FOV of 1 sr; (ii) the X--Gamma-rays spectrometer (XGS), a non-imaging spectrometer (XGS) based on SDD+CsI, covering the same FOV than the Lobster telescope extending the THESEUS energy band up to 20 MeV; and (iii) a 70cm class InfraRed Telescope (IRT) observing up to 2 microns with imaging and moderate spectral capabilities.The main scientific goals of THESEUS are to:(a) Explore the Early Universe (cosmic dawn and reionization era) by unveiling the Gamma--Ray Burst (GRBs) population in the first billion years}, determining when did the first stars form, and investigating the re-ionization epoch, the interstellar medium (ISM) and the intergalactic medium (IGM) at high redshifts.(b) Perform an unprecedented deep survey of the soft X-ray transient Universe in order to fill the present gap in the discovery space of new classes of transient; provide a fundamental step forward in the comprehension of the physics of various classes of Galactic and extra--Galactic transients, and provide real time trigger and accurate locations of transients for follow-up with next

  3. Quantum cosmology and the early universe

    International Nuclear Information System (INIS)

    Hartle, J.B.

    1983-01-01

    Despite the absence of a complete and manageable quantum theory of gravity, it is shown that considerable progress has been made in constructing cosmological models displaying the possible implications such a theory might have for the structure and dynamics of the very early universe. (U.K.)

  4. Neutrino oscillations in the early universe

    International Nuclear Information System (INIS)

    Enqvist, K.

    1990-01-01

    The oscillations of electron neutrinos into inert neutrinos may have resonant behaviour in the heat bath of the early Universe. It is shown that any initial neutrino asymmetry will be washed away by the oscillations. Neutrino oscillations would affect also primordial helium production, which implies stringent limits on the neutrino mixing parameters. (orig.)

  5. Bursts from the very early universe

    International Nuclear Information System (INIS)

    Silk, J.; Stodolsky, L.

    2006-01-01

    Bursts of weakly interacting particles such as neutrinos or even more weakly interacting particles such as wimps and gravitons from the very early universe would offer a much deeper 'look back time' to early epochs than is possible with photons. We consider some of the issues related to the existence of such bursts and their detectability. Characterizing the burst rate by a probability P per Hubble four-volume we find, for events in the radiation-dominated era, that the natural unit of description is the present intensity of the CMB times P. The existence of such bursts would make the observation of phenomena associated with very early times in cosmology at least conceptually possible. One might even hope to probe the transplanckian epoch if complexes more weakly interacting than the graviton can exist. Other conceivable applications include the potential detectability of the formation of 'pocket universes' in a multiverse

  6. Bursts from the very early universe

    Energy Technology Data Exchange (ETDEWEB)

    Silk, J. [Department of Physics, University of Oxford, Oxford OX1 3RH (United Kingdom); Stodolsky, L. [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Munich (Germany)]. E-mail: les@mppmu.mpg.de

    2006-07-27

    Bursts of weakly interacting particles such as neutrinos or even more weakly interacting particles such as wimps and gravitons from the very early universe would offer a much deeper 'look back time' to early epochs than is possible with photons. We consider some of the issues related to the existence of such bursts and their detectability. Characterizing the burst rate by a probability P per Hubble four-volume we find, for events in the radiation-dominated era, that the natural unit of description is the present intensity of the CMB times P. The existence of such bursts would make the observation of pheno associated with very early times in cosmology at least conceptually possible. One might even hope to probe the transplanckian epoch if complexes more weakly interacting than the graviton can exist. Other conceivable applications include the potential detectability of the formation of 'pocket universes' in a multiverse.

  7. Observe gamma rays to find out how the universe works

    International Nuclear Information System (INIS)

    Tapia, R.

    2015-01-01

    Each hemisphere of the Earth will host one of the two venues of the future network of telescopes Cherenkov (cta, Cherenkov telescope array) designed with the aim of covering all outer space and in stereo, a technique that allows us to reconstruct efficiently the properties of spatial events. Thanks to telescopes with which will be equipped with - greater sensitivity than the current - will be possible to study in detail one of the most powerful radiation of the Universe, gamma rays. Spain has been chosen to host the North Observatory on roque of the boys, on the island of Palma, facilities that will be form das by 20 telescopes. (Author)

  8. Discovery Mondays: The very early Universe

    CERN Multimedia

    2003-01-01

    Copyright NASARetracing the very early Universe to understand why there is "something rather than nothing" is one of the challenges facing astrophysics today. It is also the theme of the third Discovery Monday, to be held in the Microcosm on 7 July, where you will be welcomed by a number of scientists. A professional astronomer will allow you to look through his telescope and explain how it works. A cosmologist will talk to you about the very early Universe and a CERN physicist will show you how it's possible to trap antimatter. The mirror of matter, antimatter should have existed in the same quantities as matter in the very early stages of the Universe but today it seems to have virtually disappeared. Perhaps the research being done at CERN will one day explain how an infinitesimal predominance of matter over antimatter resulted in such a richly structured Universe. Come along to the Microcosm on Monday, 7 July between 7.30 p.m. and 9.00 p.m. Entrance is free http://www.cern.ch/microcosm N.B.: The Discove...

  9. Gamma-Ray Bursts Shower the Universe with Metals

    International Nuclear Information System (INIS)

    Hazi, A

    2006-01-01

    According to the results from a Livermore computer model, some of the small change jingling in your pocket contains zinc and copper created in massive gamma-ray bursts (GRBs) that rank as the most impressive light shows in the universe. Livermore astrophysicist Jason Pruet and his colleagues Rebecca Surman and Gail McLaughlin from North Carolina State University (NCSU) reported on their calculations in the February 20, 2004, issue of ''Astrophysical Journal Letters''. They found that GRBs from black holes surrounded by a disk of dense, hot plasma may have contributed heavily to the galactic inventory of elements such as calcium, scandium, titanium, zinc, and copper. ''A typical GRB of this kind briefly outshines all the stars in millions of galaxies combined'', says Pruet. ''Plus it makes about 100 times as much of some common elements as an ordinary supernova''

  10. 'RIG'- surgical gamma probe for early breast cancer detection

    International Nuclear Information System (INIS)

    Walinjkar, P.B.; Singh, Gursharan; Kumar, Umesh; Pendharkar, A.S.; Choudhary, P.S.

    2004-01-01

    Breast cancer is one of the most common cancers in women, which if detected in early stage can be effectively treated and cured. Early detection is carried out by collecting a sentinel lymph node (SLN) and testing it for cancer. The surgical gamma probe is a hand-held device used in the localization of SLN. It enables the localization of the active node. Isotope Applications Division, BARC has developed indigenously a RIG Surgical Gamma Probe in consultation with the doctors from Rajiv Gandhi Cancer Institute and Research Centre, New Delhi. The system consists of microcomputer-based gamma counting system that displays the number of pulses detected by the probe in counts per second and has an audible signal in direct correlation with the count density. The detector probe is based on the scintillation detector housed in a stainless steel housing with lead collimator. The physical parameters are a high sensitivity of 5000 cps/MBq at probe tip with good spatial resolution. The performance of this probe was clinically evaluated on the basis of spatial resolution and accuracy to detect the active node. (author)

  11. Energy input and response from prompt and early optical afterglow emission in gamma-ray bursts.

    Science.gov (United States)

    Vestrand, W T; Wren, J A; Wozniak, P R; Aptekar, R; Golentskii, S; Pal'shin, V; Sakamoto, T; White, R R; Evans, S; Casperson, D; Fenimore, E

    2006-07-13

    The taxonomy of optical emission detected during the critical first few minutes after the onset of a gamma-ray burst (GRB) defines two broad classes: prompt optical emission correlated with prompt gamma-ray emission, and early optical afterglow emission uncorrelated with the gamma-ray emission. The standard theoretical interpretation attributes prompt emission to internal shocks in the ultra-relativistic outflow generated by the internal engine; early afterglow emission is attributed to shocks generated by interaction with the surrounding medium. Here we report on observations of a bright GRB that, for the first time, clearly show the temporal relationship and relative strength of the two optical components. The observations indicate that early afterglow emission can be understood as reverberation of the energy input measured by prompt emission. Measurements of the early afterglow reverberations therefore probe the structure of the environment around the burst, whereas the subsequent response to late-time impulsive energy releases reveals how earlier flaring episodes have altered the jet and environment parameters. Many GRBs are generated by the death of massive stars that were born and died before the Universe was ten per cent of its current age, so GRB afterglow reverberations provide clues about the environments around some of the first stars.

  12. Supersymmetry in the very early universe

    International Nuclear Information System (INIS)

    Thomas, S.

    1995-06-01

    Supersymmetric flat directions can have a number of important consequences in the very early universe. Depending on the form of the SUSY breaking potential arising from the finite energy density at early times, coherent production of scalar condensates can result along such directions. This leads a cosmological disaster for Polonyi type flat directions with only Planck suppressed couplings, but can give rise to the baryon asymmetry for standard model flat directions. Flat directions are also natural candidates to act as inflatons. Achieving density fluctuations of the correct magnitude generally requires an additional hidden SUSY breaking sector

  13. QCD development in the early universe

    Energy Technology Data Exchange (ETDEWEB)

    Gromov, N. A., E-mail: gromov@dm.komisc.ru [Komi Science Center of the Ural Division of the Russian Academy of Sciences, Department of Mathematics (Russian Federation)

    2017-03-15

    The high-energy limit of Quantum Chromodynamics is generated by the contraction of its gauge groups. Contraction parameters are taken identical with those of the Electroweak Model and tend to zero when energy increases. At the infinite energy limit all quarks lose masses and have only one color degree of freedom. The limit model represents the development of Quantum Chromodynamics in the early Universe from the Big Bang up to the end of several milliseconds.

  14. Protostar formation in the early universe.

    Science.gov (United States)

    Yoshida, Naoki; Omukai, Kazuyuki; Hernquist, Lars

    2008-08-01

    The nature of the first generation of stars in the universe remains largely unknown. Observations imply the existence of massive primordial stars early in the history of the universe, and the standard theory for the growth of cosmic structure predicts that structures grow hierarchically through gravitational instability. We have developed an ab initio computer simulation of the formation of primordial stars that follows the relevant atomic and molecular processes in a primordial gas in an expanding universe. The results show that primeval density fluctuations left over from the Big Bang can drive the formation of a tiny protostar with a mass 1% that of the Sun. The protostar is a seed for the subsequent formation of a massive primordial star.

  15. High-z Universe with Gamma Ray Bursts

    Science.gov (United States)

    Kouveliotou, C.

    2011-01-01

    Gamma-Ray Bursts (GRBs) are the most luminous explosions in space and trace the cosmic star formation history back to the first generations of stars. Their bright afterglows allow us to trace the abundances of heavy elements to large distances, thereby measuring cosmic chemical evolution. To date GRBs have been detected up to distances of z=8.23 and possibly even beyond z9. This makes GRBs a unique and powerful tool to probe the high-z Universe up to the re-ionization era. We discuss the current status of the field, place it in context with other probes, and also discuss new mission concepts that have been planned to utilize GRBs as probes.

  16. Integral's first look at the gamma-ray Universe

    Science.gov (United States)

    2002-12-01

    The high-energy Universe is a violent place of exploding stars and their collapsed remnants such as the ultra-compressed neutron stars and, at the most extreme, all-consuming black holes. These celestial objects create X-rays and gamma rays that are many times more powerful than the optical radiation we can see with our eyes and optical telescopes. Integral’s Principal Investigators - the scientists responsible for the instruments on board - explain the crucial role that high-energy missions like Integral play in astronomy. “X-ray and gamma-ray astronomy is a pathfinder to unusual objects. At optical wavelengths, the number of stars is staggering. At X-ray and gamma-ray wavelengths, there are fewer objects, but the ones that remain are the really peculiar ones.” As a first test, Integral observed the Cygnus region of the sky, looking particularly at that enigmatic object, Cygnus X-1. Since the 1960s, we have known this object to be a constant generator of high-energy radiation. Most scientists believe that Cygnus X-1 is the site of a black hole, containing around five times the mass of our Sun and devouring a nearby star. Observing Cygnus X-1, which is relatively close by in our own Galaxy - ‘only’ 10 000 light years from us - is a very important step towards understanding black holes. This will also help understand the monstrous black hole - three million times the mass of our Sun - at the centre of our Galaxy. During the initial investigations, scientists had a pleasant surprise when Integral captured its first gamma-ray burst. These extraordinary celestial explosions are unpredictable, occurring from random directions about twice a day. Their precise origin is contentious: they could be the result of massive stars collapsing in the distant Universe or alternatively the result of a collision between two neutron stars. Integral promises to provide vital clues to solving this particular celestial mystery. To study these peculiarities, Integral carries two

  17. Exploring the Early Universe on Mobile Devices

    Science.gov (United States)

    Kocevski, Dale; McGrath, E. J.; CANDELS Collaboration

    2014-01-01

    The widespread adoption of smart phones and tablet computers has the potential to revolutionize the way in which educational material is shared with the general public. As part of the outreach effort for the CANDELS survey, we have developed a free interactive astronomy education application named Hubble Universe for iPad and iPhone devices. The application focuses on extragalactic science topics related to the CANDELS legacy survey, which is documenting galaxy evolution in the early universe. I will provide an overview of the application, which contains a wide range of interactive content, including 3D models of astrophysical phenomenon, informative diagrams and computer simulations. I will discuss how the application can be used to enhance classroom learning both by providing a database of interactive media and by encouraging students to explore astronomical topics away from traditional settings like the classroom or the desktop computer.

  18. A tepid model for the early universe

    International Nuclear Information System (INIS)

    Carr, B.J.; Rees, M.J.

    1977-01-01

    If the Universe started off with a photon-to-baryon ratio much less than presently observed, massive black holes would have formed at early times even if the initial density fluctuations were very small. These holes could have generated the rest of the background radiation through accretion; in this way, such a Universe might automatically evolve to have the photon-to-baryon ratio observed today. This scenario could explain why the times of decoupling and matterradiation equilibrium are comparable and might provide a critical density of primordial black holes; it could also produce galaxies with black hole 'halos'. If the initial photon-to-baryon ratio was large enough, black hole formation would not occur: one would then have to invoke an alternative scenario in which the rest of the background radiation was generated by primordial stars at a comparatively recent epoch. (orig.) [de

  19. Extended thermodynamics in the early Universe

    International Nuclear Information System (INIS)

    Lukacs, B.

    1985-01-01

    It is a general belief that in some early stages of the evolution of the Universe, unequilibrium situations played important role. In order to incorporate some deviations from thermal equilibrium into the description of the evolution, an extension of the thermodynamic formalism is given, where, using the notion of ekaentropy, new terms are introduced into the Gibbs-Duhem relation for representing the deviation. Two situations are investigated in simplified models: the primordial thermalization in the symmetric phase of GUT, and the development of a nonthermal distribution for massive neutrinos. (author)

  20. The Transient High Energy Sky and Early Universe Surveyor (THESEUS)

    Science.gov (United States)

    Amati, Lorenzo; O'Brien, Paul T.; Götz, Diego

    2016-07-01

    The Transient High Energy Sky and Early Universe Surveyor (THESEUS) is a mission concept under development by a large international collaboration aimed at exploiting gamma-ray bursts for investigating the early Universe. The main scientific objectives of THESEUS include: investigating the star formation rate and metallicity evolution of the ISM and IGM up to redshift 9-10, detecting the first generation (pop III) of stars, studying the sources and physics of re-ionization, detecting the faint end of galaxies luminosity function. These goals will be achieved through a unique combination of instruments allowing GRB detection and arcmin localization over a broad FOV (more than 1sr) and an energy band extending from several MeVs down to 0.3 keV with unprecedented sensitivity, as well as on-board prompt (few minutes) follow-up with a 0.6m class IR telescope with both imaging and spectroscopic capabilities. Such instrumentation will also allow THESEUS to unveil and study the population of soft and sub-energetic GRBs, and, more in general, to perform monitoring and survey of the X-ray sky with unprecedented sensitivity.

  1. Magnetic Fields in the Early Universe

    CERN Document Server

    Grasso, D; Grasso, D

    2001-01-01

    This review concerns the origin and the possible effects of magnetic fields in the early Universe. We start by providing to the reader with a short overview of the current state of art of observations of cosmic magnetic fields. We then illustrate the arguments in favour of a primordial origin of magnetic fields in the galaxies and in the clusters of galaxies. We argue that the most promising way to test this hypothesis is to look for possible imprints of magnetic fields on the temperature and polarization anisotropies of the cosmic microwave background radiation (CMBR). With this purpose in mind, we provide a review of the most relevant effects of magnetic fields on the CMBR. A long chapter of this review is dedicated to particle physics inspired models which predict the generation of magnetic fields during the early Universe evolution. Although it is still unclear if any of these models can really explain the origin of galactic and intergalactic magnetic fields, we show that interesting effects may arise any...

  2. Stochastic evolution of cosmological parameters in the early universe

    Indian Academy of Sciences (India)

    We develop a stochastic formulation of cosmology in the early universe, after considering the scatter in the redshift-apparent magnitude diagram in the early epochs as an observational evidence for the non-deterministic evolution of early universe. We consider the stochastic evolution of density parameter in the early ...

  3. Experimental study of the conditions for universal calibration curve for the gamma-gamma probes in 2Π-geometry

    International Nuclear Information System (INIS)

    Gyurcsak, J.; Chau, N.D.

    1989-01-01

    We present the results of the measurements performed in order of establishing the possibility of constructing the universal calibration curves for gamma-gamma density probes. It has been proved that the unit λ p , in which the source-detector distance should be expressed, has the character of a mean free path of the photons forming the high-energetic part of the spectrum. 8 refs., 12 figs., 7 tabs. (author)

  4. The Physics of the Early Universe

    International Nuclear Information System (INIS)

    Scott, Douglas

    2007-01-01

    The physics of the very small and the very large were successfully brought together in the 1980s through the idea of 'the universe as a particle accelerator'. The manifesto of this new campaign was laid out in the book 'The Early Universe' by Kolb and Turner in 1990. For at least the next decade that book was to be found on the shelves of every theorist (and many experimentalists) who professed an interest in this topic. But science marches on, and the last 10-15 years has seen an explosion in our understanding of the physics of the very earliest times and the very largest scales. Experimentally our world-view has changed utterly, through exquisitely precise measurements of the cosmic microwave background, galaxy clustering and supernova distances, with a refinement of the basic inflationary big bang paradigm into the new 'standard cosmological model'. And in tandem with these changes has been the development of new theoretical ideas, particularly involving dark energy and connections between string/brane theory and cosmology. So what is the new book for the shelves of today's cohort of young Rockys and Mikes? Despite a recent number of promising-sounding cosmology books, there is nothing at the advanced level which is broad enough to be a general introduction to the 'early universe' topic. Perhaps the best of the bunch is 'The Physics of the Early Universe', edited by E Papantonopoulos as part of Springer's series 'Lecture notes in physics'. This is a set of 9 review articles given as part of a 2003 summer school on Syros Island, Greece. Although far from perfect, the core of this book provides a solid introduction to current research in early universe physics, which should be useful for PhD students or postdoctoral researchers who want the real thing. The book starts with a competent introduction by Kyriakos Tamvakis, serving essentially as a summary of where we were in Kolb and Turner's text. We have learned since then, however, that inflation is really all

  5. Vanderbilt University Gamma Irradiation of Nano-modified Concrete (2017 Milestone Report)

    Energy Technology Data Exchange (ETDEWEB)

    Deichert, Geoffrey G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linton, Kory D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Selby, Aaron P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Reches, Yonathan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    This document outlines the irradiation of concrete specimens in the Gamma Irradiation Facility in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Two gamma irradiation runs were performed in July of 2017 on 18 reference mortar bar specimens, 26 reference cement paste bar specimens, and 28 reference cement paste tab specimens to determine the dose and temperature response of the specimens in the gamma irradiation environment. Specimens from the first two gamma irradiations were surveyed and released to Vanderbilt University. The temperature and dose information obtained informs the test parameters of the final two gamma irradiations of nano-modified concrete planned for FY 2018.

  6. Compton Composites Late in the Early Universe

    Directory of Open Access Journals (Sweden)

    Frederick Mayer

    2014-07-01

    Full Text Available Beginning roughly two hundred years after the big-bang, a tresino phase transition generated Compton-scale composite particles and converted most of the ordinary plasma baryons into new forms of dark matter. Our model consists of ordinary electrons and protons that have been bound into mostly undetectable forms. This picture provides an explanation of the composition and history of ordinary to dark matter conversion starting with, and maintaining, a critical density Universe. The tresino phase transition started the conversion of ordinary matter plasma into tresino-proton pairs prior to the the recombination era. We derive the appropriate Saha–Boltzmann equilibrium to determine the plasma composition throughout the phase transition and later. The baryon population is shown to be quickly modified from ordinary matter plasma prior to the transition to a small amount of ordinary matter and a much larger amount of dark matter after the transition. We describe the tresino phase transition and the origin, quantity and evolution of the dark matter as it takes place from late in the early Universe until the present.

  7. Brane gases in the early Universe

    International Nuclear Information System (INIS)

    Alexander, S.; Brandenberger, R.; Easson, D.

    2000-01-01

    Over the past decade it has become clear that fundamental strings are not the only fundamental degrees of freedom in string theory. D-branes are also part of the spectrum of fundamental states. In this paper we explore some possible effects of D-branes on early Universe string cosmology, starting with two key assumptions: firstly that the initial state of the Universe corresponded to a dense, hot gas in which all degrees of freedom were in thermal equilibrium, and secondly that the topology of the background space admits one-cycles. We argue by t duality that in this context the cosmological singularities are not present. We derive the equation of state of the brane gases and apply the results to suggest that, in an expanding background, the winding modes of fundamental strings will play the most important role at late times. In particular, we argue that the string winding modes will only allow four space-time dimensions to become large. The presence of brane winding modes with p>1 may lead to a hierarchy in the sizes of the extra dimensions

  8. Gamma-ray-induced bold seeded early maturing groundnut selections

    Energy Technology Data Exchange (ETDEWEB)

    Manoharan, V; Thangavelu, S [Regional Research Station, Vriddhachalam, Tamil Nadu (India)

    1990-07-01

    Full text: ''Chico'' is an early maturing (85-90 days) erect groundnut (Arachis hypogaea L.) genotype utilised in groundnut improvement to incorporate earliness in high yielding varieties. Though it has high shelling out-turn, its yield potential is low since it has small seeds. Mutation breeding was started with the objective of improving the seed size. In a preliminary experiment, dry seeds were treated with 20, 30, 40 or 50 kR of gamma rays. The M{sub 1} generation was grown during the post rainy season of 1988-1989. The M{sub 2} generation was planted as individual plant progeny rows during the rainy season of 1989. 105 progeny rows were studied, the total number of M{sub 2} plants being 1,730. All the M{sub 2} plants were harvested 90 days after sowing. Seven mutants with bold seed size were obtained. The mutants had 100 kernel weight ranging from 22.2 to 40.4 g compared to 21.1 g of control. The study is in progress. (author)

  9. Gamma-ray-induced bold seeded early maturing groundnut selections

    International Nuclear Information System (INIS)

    Manoharan, V.; Thangavelu, S.

    1990-01-01

    Full text: ''Chico'' is an early maturing (85-90 days) erect groundnut (Arachis hypogaea L.) genotype utilised in groundnut improvement to incorporate earliness in high yielding varieties. Though it has high shelling out-turn, its yield potential is low since it has small seeds. Mutation breeding was started with the objective of improving the seed size. In a preliminary experiment, dry seeds were treated with 20, 30, 40 or 50 kR of gamma rays. The M 1 generation was grown during the post rainy season of 1988-1989. The M 2 generation was planted as individual plant progeny rows during the rainy season of 1989. 105 progeny rows were studied, the total number of M 2 plants being 1,730. All the M 2 plants were harvested 90 days after sowing. Seven mutants with bold seed size were obtained. The mutants had 100 kernel weight ranging from 22.2 to 40.4 g compared to 21.1 g of control. The study is in progress. (author)

  10. Galactic Pairs in the Early Universe

    Science.gov (United States)

    Kohler, Susanna

    2018-02-01

    In the spirit of Valentines Day, today well be exploring apparent pairs of galaxies in the distant, early universe. How can we tell whether these duos are actually paired galaxies, as opposed to disguised singles?Real Pair, or Trick of the Light?In the schematic timeline of the universe, the epoch of reionization is when the first galaxies and quasars began to form and evolve. [NASA]The statistics of merging galaxies throughout the universe reveal not only direct information about how galaxies interact, but also cosmological information about the structure of the universe. While weve observed many merging galaxy pairs at low redshift, however, its much more challenging to identify these duos in the early universe.A merging pair of galaxies at high redshift appears to us as a pair of unresolved blobs that lie close to each other in the sky. But spotting such a set of objects doesnt necessarily mean were looking at a merger! There are three possible scenarios to explain an observed apparent duo:Its a pair of galaxies in a stage of merger.Its a projection coincidence; the two galaxies arent truly near each other.Its a single galaxy being gravitationally lensed by a foreground object. This strong lensing produces the appearance of multiple galaxies.Hubble photometry of one of the three galaxy groups identified at z 8, with the galaxies in the image labeled with their corresponding approximate photometric redshifts. [Adapted from Chaikin et al. 2018]Hunting for Distant DuosIn a recent study led by Evgenii Chaikin (Peter the Great St. Petersburg Polytechnic University, Russia), a team of scientists has explored the Hubble Ultra Deep Field in search ofhigh-redshift galaxies merging during the epoch of reionization, when the first galaxies formed and evolved.Using an approach called the dropout technique, which leverages the visibility of the galaxies in different wavelength filters, Chaikin and collaborators obtain approximate redshifts for an initial sample of 7

  11. The first gamma-ray bursts in the universe

    International Nuclear Information System (INIS)

    Mesler, R. A.; Pihlström, Y. M.; Whalen, Daniel J.; Smidt, Joseph; Fryer, Chris L.; Lloyd-Ronning, N. M.

    2014-01-01

    Gamma-ray bursts (GRBs) are the ultimate cosmic lighthouses, capable of illuminating the universe at its earliest epochs. Could such events probe the properties of the first stars at z ∼ 20, the end of the cosmic Dark Ages? Previous studies of Population III (Pop III) GRBs only considered explosions in the diffuse relic H II regions of their progenitors or bursts that are far more energetic than those observed to date. However, the processes that produce GRBs at the highest redshifts likely reset their local environments, creating much more complicated structures than those in which relativistic jets have been modeled so far. These structures can greatly affect the luminosity of the afterglow and hence the redshift at which it can be detected. We have now simulated Pop III GRB afterglows in H II regions, winds, and dense shells ejected by the star during the processes that produce the burst. We find that GRBs with E iso,γ = 10 51 -10 53 erg will be visible at z ≳ 20 to the next generation of near infrared and radio observatories. In many cases, the environment of the burst, and hence progenitor type, can be inferred from the afterglow light curve. Although some Pop III GRBs are visible to Swift and the Very Large Array now, the optimal strategy for their detection will be future missions like the proposed EXIST and JANUS missions with large survey areas and onboard X-ray and infrared telescopes that can track their near-infrared flux from the moment of the burst, thereby identifying their redshifts.

  12. The Early Astronomy Toolkit was Universal

    Science.gov (United States)

    Schaefer, Bradley E.

    2018-01-01

    From historical, anthropological, and archaeological records, we can reconstruct the general properties of the earliest astronomy for many cultures worldwide, and they all share many similar characteristics. The 'Early Astronomy Toolkit' (EAT) has the Earth being flat, and the heavens as a dome overhead populated by gods/heroes that rule Nature. The skies provided omens in a wide variety of manners, with eclipses, comets, and meteors always being evil and bad. Constellations were ubiquitous pictures of gods, heroes, animals, and everyday items; all for story telling. The calendars were all luni-solar, with no year counts and months only named by seasonal cues (including solstice observations and heliacal risings) with vague intercalation. Time of day came only from the sun's altitude/azimuth, while time at night came from star risings. Graves are oriented astronomically, and each culture has deep traditions of quartering the horizon. The most complicated astronomical tools were just a few sticks and stones. This is a higher level description and summary of the astronomy of all ancient cultures.This basic EAT was universal up until the Greeks, Mesopotamians, and Chinese broke out around 500 BC and afterwards. Outside the Eurasian milieu, with few exceptions (for example, planetary position measures in Mexico), this EAT represents astronomy for the rest of the world up until around 1600 AD. The EAT is present in these many cultures with virtually no variations or extensions. This universality must arise either from multiple independent inventions or by migration/diffusion. The probability of any culture independently inventing all 19 items in the EAT is low, but any such calculation has all the usual problems. Still, we realize that it is virtually impossible for many cultures to independently develop all 19 items in the EAT, so there must be a substantial fraction of migration of the early astronomical concepts. Further, the utter lack, as far as I know, of any

  13. Nature of gamma rays background radiation in new and old buildings of Qatar University

    International Nuclear Information System (INIS)

    Al-Houty, L.; Abou-Leila, H.; El-Kameesy, S.

    1987-01-01

    Measurements and analysis of gamma-background radiation spectrum in four different places of Qatar University campus were performed at the energy range 10 keV-3 MeV using hyper pure Ge-detector. The dependence of the detector absolute photopeak efficiency on gamma-ray energies was determined and correction of the data for that was also done. The absorbed dose for each gamma line was calculated and an estimation of the total absorbed dose for the detected gamma lines in the four different places was obtained. Comparison with other results was also performed

  14. Connecting QGP-Heavy Ion Physics to the Early Universe

    Energy Technology Data Exchange (ETDEWEB)

    Rafelski, Johann

    2013-10-15

    We discuss properties and evolution of quark-gluon plasma in the early Universe and compare to laboratory heavy ion experiments. We describe how matter and antimatter emerged from a primordial soup of quarks and gluons. We focus our discussion on similarities and differences between the early Universe and the laboratory experiments.

  15. Early Gender Gaps among University Graduates

    OpenAIRE

    Francesconi, Marco; Parey, Matthias

    2018-01-01

    We use data from six cohorts of university graduates in Germany to assess the extent of gender gaps in college and labor market performance twelve to eighteen months after graduation. Men and women enter college in roughly equal numbers, but more women than men complete their degrees. Women enter college with slightly better high school grades, but women leave university with slightly lower marks. Immediately following university completion, male and female full-timers work very similar numbe...

  16. Quantum aspects of early universe thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Drewes, Marco

    2010-03-15

    Various features of the observable universe can be understood as the result of nonequilibrium processes during the early stages of its history, when it was filled with a hot primordial plasma. In many cases, including cosmological freezeout processes, only a few degrees of freedom were out of equilibrium and the background plasma can be viewed as a large heat bath to which these couple. We study scalar and fermionic quantum fields out of thermal equilibrium that are weakly coupled to a large thermal bath with the goal to formulate a full quantum mechanical description of such processes. The bath composition need not be specified. Our analysis is based on Kadanoff-Baym equations, which are the exact equations of motion for the correlation functions in a nonequilibrium quantum system. We solve the equations of motion for the most general Gaussian initial density matrix, without a specific ansatz or a-priori parameterisation and for arbitrarily large deviations from equilibrium. The solutions depend on integral kernels that contain memory effects. These can in good approximation be solved analytically when the field excitations have a small decay width. The full solutions are compared to results obtained by other methods. We prove that the description in terms of a stochastic Langevin equation is equivalent to the Kadanoff-Baym equations. We show the emergence of standard Boltzmann equations as a limit of the Kadanoff-Baym equations in a dilute gas when coherences play no role and discuss quantum Boltzmann equations as an intermediate step. We analyse the properties of the solutions in terms of the equation of state and investigate the validity and implications of quasiparticle approximations. We find that the equation of state can deviate significantly from that of a gas of quasiparticles even if the resonances in the plasma show quasiparticle behaviour in decays and scatterings. A detailed discussion is devoted to the influence of modified dispersion relations and

  17. Possible role of gamma ray bursts on life extinction in the universe.

    Science.gov (United States)

    Piran, Tsvi; Jimenez, Raul

    2014-12-05

    As a copious source of gamma rays, a nearby galactic gamma ray burst (GRB) can be a threat to life. Using recent determinations of the rate of GRBs, their luminosity function, and properties of their host galaxies, we estimate the probability that a life-threatening (lethal) GRB would take place. Amongst the different kinds of GRBs, long ones are most dangerous. There is a very good chance (but no certainty) that at least one lethal GRB took place during the past 5 gigayears close enough to Earth as to significantly damage life. There is a 50% chance that such a lethal GRB took place during the last 500×10^{6}  years, causing one of the major mass extinction events. Assuming that a similar level of radiation would be lethal to life on other exoplanets hosting life, we explore the potential effects of GRBs to life elsewhere in the Galaxy and the Universe. We find that the probability of a lethal GRB is much larger in the inner Milky Way (95% within a radius of 4 kpc from the galactic center), making it inhospitable to life. Only at the outskirts of the Milky Way, at more than 10 kpc from the galactic center, does this probability drop below 50%. When considering the Universe as a whole, the safest environments for life (similar to the one on Earth) are the lowest density regions in the outskirts of large galaxies, and life can exist in only ≈10% of galaxies. Remarkably, a cosmological constant is essential for such systems to exist. Furthermore, because of both the higher GRB rate and galaxies being smaller, life as it exists on Earth could not take place at z>0.5. Early life forms must have been much more resilient to radiation.

  18. The early X-ray afterglows of optically bright and dark Gamma-Ray Bursts

    OpenAIRE

    Lin, Yi-Qing

    2006-01-01

    A systematical study on the early X-ray afterglows of both optically bright and dark gamma-ray bursts (B-GRBs and D-GRBs) observed by Swift has been presented. Our sample includes 25 GRBs. Among them 13 are B-GRBs and 12 are D-GRBs. Our results show that the distributions of the X-ray afterglow fluxes ($F_{X}$), the gamma-ray fluxes ($S_{\\gamma}$), and the ratio ($R_{\\gamma, X}$) for both the D-GRBs and B-GRBs are similar. The differences of these distributions for the two kinds of GRBs shoul...

  19. Very-high-energy gamma rays from a distant quasar: how transparent is the universe?

    Science.gov (United States)

    Albert, J; Aliu, E; Anderhub, H; Antonelli, L A; Antoranz, P; Backes, M; Baixeras, C; Barrio, J A; Bartko, H; Bastieri, D; Becker, J K; Bednarek, W; Berger, K; Bernardini, E; Bigongiari, C; Biland, A; Bock, R K; Bonnoli, G; Bordas, P; Bosch-Ramon, V; Bretz, T; Britvitch, I; Camara, M; Carmona, E; Chilingarian, A; Commichau, S; Contreras, J L; Cortina, J; Costado, M T; Covino, S; Curtef, V; Dazzi, F; De Angelis, A; De Cea Del Pozo, E; de Los Reyes, R; De Lotto, B; De Maria, M; De Sabata, F; Mendez, C Delgado; Dominguez, A; Dorner, D; Doro, M; Errando, M; Fagiolini, M; Ferenc, D; Fernández, E; Firpo, R; Fonseca, M V; Font, L; Galante, N; López, R J García; Garczarczyk, M; Gaug, M; Goebel, F; Hayashida, M; Herrero, A; Höhne, D; Hose, J; Hsu, C C; Huber, S; Jogler, T; Kneiske, T M; Kranich, D; La Barbera, A; Laille, A; Leonardo, E; Lindfors, E; Lombardi, S; Longo, F; López, M; Lorenz, E; Majumdar, P; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Mariotti, M; Martínez, M; Mazin, D; Meucci, M; Meyer, M; Miranda, J M; Mirzoyan, R; Mizobuchi, S; Moles, M; Moralejo, A; Nieto, D; Nilsson, K; Ninkovic, J; Otte, N; Oya, I; Panniello, M; Paoletti, R; Paredes, J M; Pasanen, M; Pascoli, D; Pauss, F; Pegna, R G; Perez-Torres, M A; Persic, M; Peruzzo, L; Piccioli, A; Prada, F; Prandini, E; Puchades, N; Raymers, A; Rhode, W; Ribó, M; Rico, J; Rissi, M; Robert, A; Rügamer, S; Saggion, A; Saito, T Y; Salvati, M; Sanchez-Conde, M; Sartori, P; Satalecka, K; Scalzotto, V; Scapin, V; Schmitt, R; Schweizer, T; Shayduk, M; Shinozaki, K; Shore, S N; Sidro, N; Sierpowska-Bartosik, A; Sillanpää, A; Sobczynska, D; Spanier, F; Stamerra, A; Stark, L S; Takalo, L; Tavecchio, F; Temnikov, P; Tescaro, D; Teshima, M; Tluczykont, M; Torres, D F; Turini, N; Vankov, H; Venturini, A; Vitale, V; Wagner, R M; Wittek, W; Zabalza, V; Zandanel, F; Zanin, R; Zapatero, J

    2008-06-27

    The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar Radio Source (in short: radio quasar) 3C 279, at a distance of more than 5 billion light-years (a redshift of 0.536). No quasar has been observed previously in very-high-energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high-energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts.

  20. Hot hadronic matter in the early universe

    International Nuclear Information System (INIS)

    Bowers, R.L.; Dykema, P.G.; Gleeson, A.M.

    1977-04-01

    A fully relativistic equation of state for hot baryonic matter was used to investigate the strong interaction contribution to the equation of motion of the Friedmann universe. A pronounced softening of the equation of state is observed near nuclear density. The significance of the results is analyzed in terms of analytic solutions for the Friedmann cosmology

  1. Sterile neutrinos in the early universe

    NARCIS (Netherlands)

    Ivashko, Artem

    2015-01-01

    Although the Standard Model of elementary particles successfully describes the Universe up to the smallest known scales, we know that there exists a number of observational phenomena, which do not find explanation in the framework of this theory. Among these problems are Neutrino Oscillations, Dark

  2. Early optical polarization of a gamma-ray burst afterglow.

    Science.gov (United States)

    Mundell, Carole G; Steele, Iain A; Smith, Robert J; Kobayashi, Shiho; Melandri, Andrea; Guidorzi, Cristiano; Gomboc, Andreja; Mottram, Chris J; Clarke, David; Monfardini, Alessandro; Carter, David; Bersier, David

    2007-03-30

    We report the optical polarization of a gamma-ray burst (GRB) afterglow, obtained 203 seconds after the initial burst of gamma-rays from GRB 060418, using a ring polarimeter on the robotic Liverpool Telescope. Our robust (2sigma) upper limit on the percentage of polarization, less than 8%, coincides with the fireball deceleration time at the onset of the afterglow. The combination of the rate of decay of the optical brightness and the low polarization at this critical time constrains standard models of GRB ejecta, ruling out the presence of a large-scale ordered magnetic field in the emitting region.

  3. Ultra-Fast Flash Observatory for observation of early photons from gamma ray bursts

    DEFF Research Database (Denmark)

    Park, I. H.; Ahmad, S.; Barrillon, P.

    2012-01-01

    We describe the space project of Ultra-Fast Flash Observatory (UFFO) which will observe early optical photons from gamma-ray bursts (GRBs) with a sub-second optical response, for the first time. The UFFO will probe the early optical rise of GRBs, opening a completely new frontier in GRB and trans...

  4. Altered Evoked Gamma-Band Responses Reveal Impaired Early Visual Processing in ADHD Children

    Science.gov (United States)

    Lenz, Daniel; Krauel, Kerstin; Flechtner, Hans-Henning; Schadow, Jeanette; Hinrichs, Hermann; Herrmann, Christoph S.

    2010-01-01

    Neurophysiological studies yield contrary results whether attentional problems of patients with attention-deficit/hyperactivity disorder (ADHD) are related to early visual processing deficits or not. Evoked gamma-band responses (GBRs), being among the first cortical responses occurring as early as 90 ms after visual stimulation in human EEG, have…

  5. Numerical relativity and the early Universe

    Directory of Open Access Journals (Sweden)

    Mironov Sergey

    2016-01-01

    Full Text Available We consider numerical simulations in general relativity in ADM formalism with cosmological ansatz for the metric. This ansatz is convenient for investigations of the Universe creation in laboratory with Galileons. Here we consider toy model for the software: spherically symmetric scalar field minimally coupled to the gravity with asymmetric double well potential. We studied the dependence of radius of critical bubble on the parameters of the theory. It demonstrates the wide applicability of thin-wall approximation. We did not find any kind of stable bubble solution.

  6. The Early Universe. Facts and fiction. 4. ed.

    International Nuclear Information System (INIS)

    Boerner, G.

    2003-01-01

    The following topics are covered in this completely new written textbook: The standard big bang model, thermodynamics of the Early universe, gauge theories and standard model, grand unification models, baryon synthesis, inflationary universe, dark matter and galaxy formation, evolution of small perturbations, non-linear structure formation (WL)

  7. The early period of the universal Fermi interaction

    International Nuclear Information System (INIS)

    Tiomno, J.

    1984-01-01

    A critical analysis of the contributions which lead, in the early period, to the discovery of the universality of Fermi-type weak interactions is made. In particular the current references to this universality as 'Puppi's triangle' are shown to be incorrect. (Author) [pt

  8. Australian Early Childhood Educators: From Government Policy to University Practice

    Science.gov (United States)

    Davies, Sharon; Trinidad, Sue

    2013-01-01

    This article provides an overview of the Australian Federal Government initiatives in the area of early childhood with regard to the provision of early childhood education and care. These changes have influenced a Western Australian university to develop an innovative birth to 8 years preservice educator education curriculum. Using an ecological…

  9. Formation of structures in the very early universe

    International Nuclear Information System (INIS)

    Bertolami Neto, O.; Marques, G.C.; Ventura, I.

    1984-01-01

    An alternative picture of cosmological phase transition is sketched and its implications to the formation of structures in the very early Universe is studied. It is shown that the condensation of walls at high temperatures leads to fluctuations which are in accordance to all necessary conditions to the formation of structures in the Universe. Furthermore the number of aglutination centers is roughly equal to the numbers of great structures observed in the Universe today. (Author) [pt

  10. A cerebral arteriovenous malformation grading system for gamma knife radiosurgery with the aim of early obliteration

    International Nuclear Information System (INIS)

    Negishi, Masatoshi; Inoue, Hiroshi K.; Hirato, Masafumi; Yokoe, Takao; Iino, Yuichi; Ohye, Chihiro; Shibazaki, Tohru

    1998-01-01

    Bleeding in the latency period before obliteration considerably worsens the prognosis of cerebral arteriovenous malformations (AVMs). Bleeding risk should be considered and total obliteration should performed as early as possible. In this study we investigated factors related to early obliteration following Gamma Knife radiosurgery and proposed a grading system for AVMs. Forty-six patients with cerebral AVMs followed angiographically within twelve months after Gamma Knife radiosurgery were analyzed. Four factors, volume, type (categorized by our own method), location, and marginal dose were found to be correlated with early obliteration rate. We scored these factors, and categorized the scores into a grade O to 6 Gamma Knife Score (GKS), and evaluated the obliteration rate of each grade. The total obliteration rate in twelve months according to grade was: grades 0 and 1, 61.9%; grades 2 and 3, 36.0%, grades 4 and 5, 16.7%. AVMs with a low GKS (grades 0 and 1) had a high early obliteration rate and seemed suitable for Gamma Knife radiosurgery. Since early obliteration is difficult to obtain in the high grade group, endovascular surgery should be considered to reduce the GKS before Gamma Knife radiosurgery. (author)

  11. Observe gamma rays to find out how the universe works; Observar rayos gamma para saber como funciona El universo

    Energy Technology Data Exchange (ETDEWEB)

    Tapia, R.

    2015-07-01

    Each hemisphere of the Earth will host one of the two venues of the future network of telescopes Cherenkov (cta, Cherenkov telescope array) designed with the aim of covering all outer space and in stereo, a technique that allows us to reconstruct efficiently the properties of spatial events. Thanks to telescopes with which will be equipped with - greater sensitivity than the current - will be possible to study in detail one of the most powerful radiation of the Universe, gamma rays. Spain has been chosen to host the North Observatory on roque of the boys, on the island of Palma, facilities that will be form das by 20 telescopes. (Author)

  12. GRB 090727 AND GAMMA-RAY BURSTS WITH EARLY-TIME OPTICAL EMISSION

    International Nuclear Information System (INIS)

    Kopač, D.; Gomboc, A.; Japelj, J.; Kobayashi, S.; Mundell, C. G.; Bersier, D.; Cano, Z.; Smith, R. J.; Steele, I. A.; Virgili, F. J.; Guidorzi, C.; Melandri, A.

    2013-01-01

    We present a multi-wavelength analysis of Swift gamma-ray burst GRB 090727, for which optical emission was detected during the prompt gamma-ray emission by the 2 m autonomous robotic Liverpool Telescope and subsequently monitored for a further two days with the Liverpool and Faulkes Telescopes. Within the context of the standard fireball model, we rule out a reverse shock origin for the early-time optical emission in GRB 090727 and instead conclude that the early-time optical flash likely corresponds to emission from an internal dissipation process. Putting GRB 090727 into a broader observational and theoretical context, we build a sample of 36 gamma-ray bursts (GRBs) with contemporaneous early-time optical and gamma-ray detections. From these GRBs, we extract a sub-sample of 18 GRBs, which show optical peaks during prompt gamma-ray emission, and perform detailed temporal and spectral analysis in gamma-ray, X-ray, and optical bands. We find that in most cases early-time optical emission shows sharp and steep behavior, and notice a rich diversity of spectral properties. Using a simple internal shock dissipation model, we show that the emission during prompt GRB phase can occur at very different frequencies via synchrotron radiation. Based on the results obtained from observations and simulation, we conclude that the standard external shock interpretation for early-time optical emission is disfavored in most cases due to sharp peaks (Δt/t < 1) and steep rise/decay indices, and that internal dissipation can explain the properties of GRBs with optical peaks during gamma-ray emission

  13. Reconstructing the Gamma-Ray Photon Optical Depth of the Universe To Z Approx. 4 from Multiwavelength Galaxy Survey Data

    Science.gov (United States)

    Helgason, Kari; Kashlinsky, Alexander

    2012-01-01

    Reconstructing the Gamma-Ray Photon Optical Depth of the Universe To Z Approx. 4fFrom Multiwavelength Galaxy Survey Data We reconstruct the gamma-ray opacity of the universe out to z approx. photons already at z approx. < 0.2 and reaching tau approx 10 at z = 1. Comparing with the currently available Fermi/LAT gamma-ray burst and blazar data shows that there is room for significant emissions originating in the first stars era.

  14. Black holes in the early Universe.

    Science.gov (United States)

    Volonteri, Marta; Bellovary, Jillian

    2012-12-01

    The existence of massive black holes (MBHs) was postulated in the 1960s, when the first quasars were discovered. In the late 1990s their reality was proven beyond doubt in the Milky way and a handful nearby galaxies. Since then, enormous theoretical and observational efforts have been made to understand the astrophysics of MBHs. We have discovered that some of the most massive black holes known, weighing billions of solar masses, powered luminous quasars within the first billion years of the Universe. The first MBHs must therefore have formed around the time the first stars and galaxies formed. Dynamical evidence also indicates that black holes with masses of millions to billions of solar masses ordinarily dwell in the centers of today's galaxies. MBHs populate galaxy centers today, and shone as quasars in the past; the quiescent black holes that we detect now in nearby bulges are the dormant remnants of this fiery past. In this review we report on basic, but critical, questions regarding the cosmological significance of MBHs. What physical mechanisms led to the formation of the first MBHs? How massive were the initial MBH seeds? When and where did they form? How is the growth of black holes linked to that of their host galaxy? The answers to most of these questions are works in progress, in the spirit of these reports on progress in physics.

  15. Black holes in the early Universe

    International Nuclear Information System (INIS)

    Volonteri, Marta; Bellovary, Jillian

    2012-01-01

    The existence of massive black holes (MBHs) was postulated in the 1960s, when the first quasars were discovered. In the late 1990s their reality was proven beyond doubt in the Milky way and a handful nearby galaxies. Since then, enormous theoretical and observational efforts have been made to understand the astrophysics of MBHs. We have discovered that some of the most massive black holes known, weighing billions of solar masses, powered luminous quasars within the first billion years of the Universe. The first MBHs must therefore have formed around the time the first stars and galaxies formed. Dynamical evidence also indicates that black holes with masses of millions to billions of solar masses ordinarily dwell in the centers of today's galaxies. MBHs populate galaxy centers today, and shone as quasars in the past; the quiescent black holes that we detect now in nearby bulges are the dormant remnants of this fiery past. In this review we report on basic, but critical, questions regarding the cosmological significance of MBHs. What physical mechanisms led to the formation of the first MBHs? How massive were the initial MBH seeds? When and where did they form? How is the growth of black holes linked to that of their host galaxy? The answers to most of these questions are works in progress, in the spirit of these reports on progress in physics. (review article)

  16. Dynamics of stringy congruence in the early universe

    International Nuclear Information System (INIS)

    Cho, Yong Seung; Hong, Soon-Tae

    2011-01-01

    We study twist and shear aspects of the stingy geodesic surface congruence. Under some natural conditions we derive the equations of the twist and shear in terms of the expansion of the Universe. We observe in this higher dimensional cosmology that, as the early universe evolves with expansion rate, the twist of the stringy congruence decreases exponentially and the initial twist value should be large enough to sustain the rotations of the ensuing universe, while the effects of the shear are negligible to produce the isotropic and homogeneous universe. We also investigate the twist and shear of the geodesic surface congruence of the null strings.

  17. Early Predictors of First-Year Academic Success at University: Pre-University Effort, Pre-University Self-Efficacy, and Pre-University Reasons for Attending University

    Science.gov (United States)

    van Herpen, Sanne G. A.; Meeuwisse, Marieke; Hofman, W. H. Adriaan; Severiens, Sabine E.; Arends, Lidia R.

    2017-01-01

    Given the large number of dropouts in the 1st year at university, it is important to identify early predictors of 1st-year academic success. The present study (n = 453 first-year students) contributes to literature on the transition from secondary to higher education by investigating how the non-cognitive factors "pre-university" effort…

  18. The Extragalactic Background Light and the Gamma-ray Opacity of the Universe

    Science.gov (United States)

    Dwek, Eli; Krennrich, Frank

    2012-01-01

    The extragalactic background light (EBL) is one of the fundamental observational quantities in cosmology. All energy releases from resolved and unresolved extragalactic sources, and the light from any truly diffuse background, excluding the cosmic microwave background (CMB), contribute to its intensity and spectral energy distribution. It therefore plays a crucial role in cosmological tests for the formation and evolution of stellar objects and galaxies, and for setting limits on exotic energy releases in the universe. The EBL also plays an important role in the propagation of very high energy gamma-rays which are attenuated en route to Earth by pair producing gamma-gamma interactions with the EBL and CMB. The EBL affects the spectrum of the sources, predominantly blazars, in the approx 10 GeV to 10 TeV energy regime. Knowledge of the EBL intensity and spectrum will allow the determination of the intrinsic blazar spectrum in a crucial energy regime that can be used to test particle acceleration mechanisms and VHE gamma-ray production models. Conversely, knowledge of the intrinsic gamma-ray spectrum and the detection of blazars at increasingly higher redshifts will set strong limits on the EBL and its evolution. This paper reviews the latest developments in the determination of the EBL and its impact on the current understanding of the origin and production mechanisms of gamma-rays in blazars, and on energy releases in the universe. The review concludes with a summary and future directions in Cherenkov Telescope Array techniques and in infrared ground-based and space observatories that will greatly improve our knowledge of the EBL and the origin and production of very high energy gamma-rays.

  19. Observation of early photons from gamma-ray bursts with the Lomonosov / UFFO-pathfinder

    DEFF Research Database (Denmark)

    Jeong, S.; Brandt, Søren; Budtz-Jørgensen, Carl

    2014-01-01

    UFFO-pathfinder is a pioneering space mission to observe the early evolution of Gamma-ray Bursts using a fast slewing strategy. It consists of the Slewing Mirror Telescope, for rapid pointing at UV/optical wavelengths and the UFFO Burst Alert and Trigger Telescope. It has a total weight of ~ 20 k...

  20. Fate of Yang-Mills black hole in early Universe

    Energy Technology Data Exchange (ETDEWEB)

    Nakonieczny, Lukasz; Rogatko, Marek [Institute of Physics Maria Curie-Sklodowska University 20-031 Lublin, pl. Marii Curie-Sklodowskiej 1 (Poland)

    2013-02-21

    According to the Big Bang Theory as we go back in time the Universe becomes progressively hotter and denser. This leads us to believe that the early Universe was filled with hot plasma of elementary particles. Among many questions concerning this phase of history of the Universe there are questions of existence and fate of magnetic monopoles and primordial black holes. Static solution of Einstein-Yang-Mills system may be used as a toy model for such a black hole. Using methods of field theory we will show that its existence and regularity depend crucially on the presence of fermions around it.

  1. Early Tracking or Finally Leaving? Determinants of Early Study Success in First-Year University Students

    Science.gov (United States)

    Brouwer, Jasperina; Jansen, Ellen; Hofman, Adriaan; Flache, Andreas

    2016-01-01

    Two theoretical approaches underlie this investigation of the determinants of early study success among first-year university students. Specifically, to extend Walberg's educational productivity model, this study draws on the expectancy-value theory of achievement motivation in a contemporary university context. The survey data came from 407…

  2. Early Childhood Development and E-Learning in Africa: The Early Childhood Development Virtual University Programme

    Science.gov (United States)

    Pence, Alan

    2007-01-01

    This article explores the development and evaluation of the graduate-level Early Childhood Development Virtual University (ECDVU) programme in Sub-Saharan Africa from 2001 through to 2004. It outlines the history of the ECDVU and the establishing of a Sub-Saharan programme for future leaders in the early childhood field guided by the key principle…

  3. Is the Universe More Transparent to Gamma Rays than Previously Thought?

    Science.gov (United States)

    Stecker, Floyd W.; Scully, Sean T.

    2009-01-01

    The MAGIC collaboration has recently reported the detection of the strong gamma-ray blazar 3C279 during a 1-2 day flare. They have used their spectral observations to draw conclusions regarding upper limits on the opacity of the Universe to high energy gamma-rays and, by implication, upper limits on the extragalactic mid-infrared background radiation. In this paper we examine the effect of gamma-ray absorption by the extragalactic infrared radiation on intrinsic spectra for this blazar and compare our results with the observational data on 3C279. We find agreement with our previous results, contrary to the recent assertion of the MAGIC group that the Universe is more transparent to gamma-rays than our calculations indicate. Our analysis indicates that in the energy range between approx. 80 and approx. 500 GeV, 3C279 has a best-fit intrinsic spectrum with a spectral index approx. 1.78 using our fast evolution model and approx. 2.19 using our baseline model. However, we also find that spectral indices in the range of 1.0 to 3.0 are almost as equally acceptable as the best fit spectral indices. Assuming the same intrinsic spectral index for this flare as for the 1991 flare from 3C279 observed by EGRET, viz., 2.02, which lies between our best fit indeces, we estimate that the MAGIC flare was approx.3 times brighter than the EGRET flare observed 15 years earlier.

  4. Quantum theories of the early universe - a critical appraisal

    International Nuclear Information System (INIS)

    Hu, B.L.

    1988-01-01

    A critical appraisal of certain general problems in the study of quantum processes in curved space as applied to the construction of theories of the early universe is presented. Outstanding issues in different cosmological models and the degree of success of different quantum processes in addressing these issues are summarized. (author)

  5. GUTs and supersymmetric GUTs in the very early universe

    International Nuclear Information System (INIS)

    Ellis, J.

    1983-01-01

    This talk is intended as background material for many of the other talks treating the possible applications of GUTs to the very early universe. It starts with a review of the present theoretical and phenomenological status of GUTs and then goes on to raise some new issues for their prospective cosmological applications which arise in supersymmetric (susy) GUTs. (author)

  6. Thermodynamic fluctuations and the monopole density of the early Universe

    International Nuclear Information System (INIS)

    Diosi, L.; Lukacs, B.

    1984-10-01

    The probability of thermodynamic fluctuations is calculated by explicitly using the Riemannian structure of the thermodynamic state space. By means of this probability distribution, a correlation volume can be defined. Identifying this volume with one domain in the GUT continuum at the symmetry breaking phase transition in the early Universe, a prediction can be obtained for the primordial monopole density. (author)

  7. Gravitino Condensates in the Early Universe and Inflation

    CERN Document Server

    Mavromatos, Nick E

    2015-01-01

    We review work on the formation of gravitino condensates via the super-Higgs effect in the early Universe. This is a scenario for both inflating the early universe and breaking local supersymmetry (supergravity), entirely independent of any coupling to external matter. The goldstino mode associated with the breaking of (global) supersymmetry is "eaten" by the gravitino field, which becomes massive (via its own vacuum condensation) and breaks the local supersymmetry (supergravity) dynamically. The most natural association of gravitino condensates with inflation proceeds in an indirect way, via a Starobinsky-inflation-type phase. The higher-order curvature corrections of the (quantum) effective action of gravitino condensates induced by integrating out massive gravitino degrees of freedom in a curved space-time background, in the broken-supergravity phase, are responsible for inducing a scalar mode which inflates the Universe. The scenario is in agreement with Planck data phenomenology in a natural and phenomen...

  8. Endogenously generated gamma-band oscillations in early visual cortex: A neurofeedback study.

    Science.gov (United States)

    Merkel, Nina; Wibral, Michael; Bland, Gareth; Singer, Wolf

    2018-04-26

    Human subjects were trained with neurofeedback (NFB) to enhance the power of narrow-band gamma oscillations in circumscribed regions of early visual cortex. To select the region and the oscillation frequency for NFB training, gamma oscillations were induced with locally presented drifting gratings. The source and frequency of these induced oscillations were determined using beamforming methods. During NFB training the power of narrow band gamma oscillations was continuously extracted from this source with online beamforming and converted into the pitch of a tone signal. We found that seven out of ten subjects were able to selectively increase the amplitude of gamma oscillations in the absence of visual stimulation. One subject however failed completely and two subjects succeeded to manipulate the feedback signal by contraction of muscles. In all subjects the attempts to enhance visual gamma oscillations were associated with an increase of beta oscillations over precentral/frontal regions. Only successful subjects exhibited an additional marked increase of theta oscillations over precentral/prefrontal and temporal regions whereas unsuccessful subjects showed an increase of alpha band oscillations over occipital regions. We argue that spatially confined networks in early visual cortex can be entrained to engage in narrow band gamma oscillations not only by visual stimuli but also by top down signals. We interpret the concomitant increase in beta oscillations as indication for an engagement of the fronto-parietal attention network and the increase of theta oscillations as a correlate of imagery. Our finding support the application of NFB in disease conditions associated with impaired gamma synchronization. © 2018 Wiley Periodicals, Inc.

  9. Gamma-Ray Bursts: Lighting Up the High-Redshift Universe

    Science.gov (United States)

    Toy, Vicki Louise

    Gamma-ray bursts (GRBs) are the most luminous events in the Universe with Egamma,iso ˜ 1048-54 erg. Leading models hypothesize that GRBs are created from inter- nal collisions within collimated and ultrarelativistic jets. The jets then shock-heat the surrounding material (e.g. interstellar medium) to create GRB afterglows. These afterglows are extremely useful probes of the Universe because long GRBs are (1) bright events that can be used as backlights for absorption studies, (2) able to probe at all redshifts massive stars exist, and (3) transient events that allow us to follow- up on the host galaxies at late times. In this thesis we study the environments of GRBs. We first explore the relationship between GRB and supernova (SN) using a nearby GRB-SN (GRB 130702A/SN 2013dx) at z = 0.145. There are only nine other GRB-SNe that were close enough to have extensive spectroscopic and photometric follow-up of the SN at late times. We create a quasi-bolometic light curve of SN 2013dx and fit an analytical equation to the quasi-bolometric light curve combined with measurements of the photospheric velocity to determine SN parameters: mass of 56Ni, kinetic energy, and ejecta mass. We examine the relationship between SN parameters and E gamma,iso for the 10 well-studied GRB-SNe, but find no correlations despite numerical simulation predictions that the mass of 56Ni should correlate with the degree of asymmetry. We then move to larger distance scales and use GRB afterglows as bright back- lights to study distant galaxies. We examine the galactic environments of Damped Lyman-alpha systems (DLAs; NHI ≥ 1020.3 cm-2 ) identified with GRB afterglows at z ˜ 2 - 6. We use late-time photometry after the GRB afterglow has faded to determine star formation rates (SFRs) from rest-frame ultraviolet measurements or spectral energy distribution (SED) models from multiband photometry. We com- pare our sample's SFRs to a sample of quasars (QSOs) DLA host galaxies. Despite the

  10. Gamma-scintigraphy and early hepatocellular dysfunction during posttraumatic sepsis.

    Science.gov (United States)

    McGinty, M P; Stewart, R M; Fabian, M J; Fabian, T C; Proctor, K G

    1994-09-01

    To determine whether the hepatic conjugation-detoxification function was altered during sepsis, the metabolism of bilirubin was measured with gamma-scintigraphy. Time-activity curves were generated after a radiolabeled bilirubin analog (technetium 99m-mebrofenin, hepatoiminodiacetic acid [HIDA]) was administered to anesthetized (fentanyl) mongrel pigs in the following conditions: control (n = 16); 30 minutes after 5 micrograms/kg intravenous Escherichia coli endotoxin (LPS; n = 6); 30 minutes after trauma (40% arterial hemorrhage plus soft tissue injury, n = 9); 72 hours after sham trauma (n = 6); 72 hours after fluid resuscitated trauma either before (n = 9) or 30 minutes after (n = 10) LPS administration. All were ventilated with 65% O2 and instrumented with pulmonary artery oximetric catheters. After trauma plus LPS, the rate of HIDA uptake was depressed 20% to 30% (p trauma alone or LPS alone, uptake was not altered and elimination was prolonged less than twofold (p trauma alone (62 +/- 10), LPS alone (79 +/- 6), or trauma plus LPS (71 +/- 6) compared with control (102 +/- 5), sham (112 +/- 11), or pre-LPS (120 +/- 10) (p trauma or LPS alone or in combination. Changes in HIDA uptake-excretion within 30 minutes of LPS after resuscitated trauma coincided with neutropenia and pulmonary hypertension and preceded a hyperdynamic inflammatory state characterized by increased CI (194 +/- 19 ml/min/kg, p hepatic reserve and this occult dysfunction in the conjugation-detoxification system or bilirubin metabolism is unmasked by LPS; (2) hepatic dysfunction could have a role in the pathogenesis of the hyperdynamic circulatory response evoked by LPS because HIDA clearance was reduced before CI increased or systemic vascular resistance decreased; (3) HIDA clearance is a rapid, reliable, and inexpensive estimate of bilirubin metabolism that may have a practical application in patients with septic trauma or others with occult liver dysfunction.

  11. Interpreting the gamma statistic in phylogenetic diversification rate studies: a rate decrease does not necessarily indicate an early burst.

    Directory of Open Access Journals (Sweden)

    James A Fordyce

    Full Text Available BACKGROUND: Phylogenetic hypotheses are increasingly being used to elucidate historical patterns of diversification rate-variation. Hypothesis testing is often conducted by comparing the observed vector of branching times to a null, pure-birth expectation. A popular method for inferring a decrease in speciation rate, which might suggest an early burst of diversification followed by a decrease in diversification rate is the gamma statistic. METHODOLOGY: Using simulations under varying conditions, I examine the sensitivity of gamma to the distribution of the most recent branching times. Using an exploratory data analysis tool for lineages through time plots, tree deviation, I identified trees with a significant gamma statistic that do not appear to have the characteristic early accumulation of lineages consistent with an early, rapid rate of cladogenesis. I further investigated the sensitivity of the gamma statistic to recent diversification by examining the consequences of failing to simulate the full time interval following the most recent cladogenic event. The power of gamma to detect rate decrease at varying times was assessed for simulated trees with an initial high rate of diversification followed by a relatively low rate. CONCLUSIONS: The gamma statistic is extraordinarily sensitive to recent diversification rates, and does not necessarily detect early bursts of diversification. This was true for trees of various sizes and completeness of taxon sampling. The gamma statistic had greater power to detect recent diversification rate decreases compared to early bursts of diversification. Caution should be exercised when interpreting the gamma statistic as an indication of early, rapid diversification.

  12. Interpreting the gamma statistic in phylogenetic diversification rate studies: a rate decrease does not necessarily indicate an early burst.

    Science.gov (United States)

    Fordyce, James A

    2010-07-23

    Phylogenetic hypotheses are increasingly being used to elucidate historical patterns of diversification rate-variation. Hypothesis testing is often conducted by comparing the observed vector of branching times to a null, pure-birth expectation. A popular method for inferring a decrease in speciation rate, which might suggest an early burst of diversification followed by a decrease in diversification rate is the gamma statistic. Using simulations under varying conditions, I examine the sensitivity of gamma to the distribution of the most recent branching times. Using an exploratory data analysis tool for lineages through time plots, tree deviation, I identified trees with a significant gamma statistic that do not appear to have the characteristic early accumulation of lineages consistent with an early, rapid rate of cladogenesis. I further investigated the sensitivity of the gamma statistic to recent diversification by examining the consequences of failing to simulate the full time interval following the most recent cladogenic event. The power of gamma to detect rate decrease at varying times was assessed for simulated trees with an initial high rate of diversification followed by a relatively low rate. The gamma statistic is extraordinarily sensitive to recent diversification rates, and does not necessarily detect early bursts of diversification. This was true for trees of various sizes and completeness of taxon sampling. The gamma statistic had greater power to detect recent diversification rate decreases compared to early bursts of diversification. Caution should be exercised when interpreting the gamma statistic as an indication of early, rapid diversification.

  13. The Early Universe: Searching for Evidence of Cosmic Inflation

    Science.gov (United States)

    Chuss, David T.

    2012-01-01

    In the past two decades, our understanding of the evolution and fate of the universe has increased dramatically. This "Age of Precision Cosmology" has been ushered in by measurements that have both elucidated the details of the Big Bang cosmology and set the direction for future lines of inquiry. Our universe appears to consist of 5% baryonic matter; 23% of the universe's energy content is dark matter which is responsible for the observed structure in the universe; and 72% of the energy density is so-called "dark energy" that is currently accelerating the expansion of the universe. In addition, our universe has been measured to be geometrically flat to 1 %. These observations and related details of the Big Bang paradigm have hinted that the universe underwent an epoch of accelerated expansion known as "inflation" early in its history. In this talk, I will review the highlights of modern cosmology, focusing on the contributions made by measurements of the cosmic microwave background, the faint afterglow of the Big Bang. I will also describe new instruments designed to measure the polarization of the cosmic microwave background in order to search for evidence of cosmic inflation.

  14. Early predictors of first-year academic success at university : Pre-university effort, pre-university self-efficacy, and pre-university reasons for attending university

    NARCIS (Netherlands)

    van Herpen, Sanne G.A.; Meeuwisse, Marieke; Hofman, W. H.Adriaan; Severiens, Sabine E.; Arends, Lidia R.

    Given the large number of dropouts in the 1st year at university, it is important to identify early predictors of 1st-year academic success. The present study (n = 453 first-year students) contributes to literature on the transition from secondary to higher education by investigating how the

  15. Early Universe synthesis of asymmetric dark matter nuggets

    Science.gov (United States)

    Gresham, Moira I.; Lou, Hou Keong; Zurek, Kathryn M.

    2018-02-01

    We compute the mass function of bound states of asymmetric dark matter—nuggets—synthesized in the early Universe. We apply our results for the nugget density and binding energy computed from a nuclear model to obtain analytic estimates of the typical nugget size exiting synthesis. We numerically solve the Boltzmann equation for synthesis including two-to-two fusion reactions, estimating the impact of bottlenecks on the mass function exiting synthesis. These results provide the basis for studying the late Universe cosmology of nuggets in a future companion paper.

  16. Early Presbyterian influences at the University of Pretoria

    Directory of Open Access Journals (Sweden)

    Graham Duncan

    2008-01-01

    Full Text Available Presbyterianism, through two significant personalities, provided an important impetus to the formation and development of the early University of Pretoria. Their contribution has to be understood in terms of the contexts of their Scottish Presbyterian heritage, South Africa in the early years of the twentieth century and the state of higher education prevalent at that time. Together these contexts may be described as political, religious and educational. Prof AC Paterson made significant contributions both in teaching and administration at the institutional level. Prof E Macmillan made his contribution in the field of teaching, but never divorced from the very context where ministry has to be exercised.

  17. GammaScorpion: mobile gamma-ray tomography system for early detection of basal stem rot in oil palm plantations

    Science.gov (United States)

    Abdullah, Jaafar; Hassan, Hearie; Shari, Mohamad Rabaie; Mohd, Salzali; Mustapha, Mahadi; Mahmood, Airwan Affendi; Jamaludin, Shahrizan; Ngah, Mohd Rosdi; Hamid, Noor Hisham

    2013-03-01

    Detection of the oil palm stem rot disease Ganoderma is a major issue in estate management and production in Malaysia. Conventional diagnostic techniques are difficult and time consuming when using visual inspection, and destructive and expensive when based on the chemical analysis of root or stem tissue. As an alternative, a transportable gamma-ray computed tomography system for the early detection of basal stem rot (BSR) of oil palms due to Ganoderma was developed locally at the Malaysian Nuclear Agency, Kajang, Malaysia. This system produces high quality tomographic images that clearly differentiate between healthy and Ganoderma infected oil palm stems. It has been successfully tested and used to detect the extent of BSR damage in oil palm plantations in Malaysia without the need to cut down the trees. This method offers promise for in situ inspection of oil palm stem diseases compared to the more conventional methods.

  18. Dual QCD and phase transition in early universe

    International Nuclear Information System (INIS)

    Ranjan, Akhilesh; Raina, P.K.; Nandan, Hemwati

    2009-01-01

    The quantum chromodynamics (QCD) vacuum with condensed monopoles/ dyons (i.e., a dual Ginzburg- Landau (DGL) type model of QCD or dual QCD) has been quite successful to describe the large-distance behavior of QCD vacuum. Further, such DGL theory of QCD at finite temperature is also found to be useful in studying the phase transition process as believed to occur in early universe. In the present article, we have used the DGL theory of QCD with dyons to study the hadronisation in early universe. The effective potential at finite temperature is calculated. The notions of the phase transition in the background of the dyonically condensed QCD vacuum has been investigated by calculating the critical temperature in view of the temperature dependent couplings

  19. Was there an early reionization component in our universe?

    Science.gov (United States)

    Villanueva-Domingo, Pablo; Gariazzo, Stefano; Gnedin, Nickolay Y.; Mena, Olga

    2018-04-01

    A deep understanding of the epoch of reionization is still missing in our knowledge of the universe. While future probes will allow us to test the precise evolution of the free electron fraction from redshifts between zsimeq 6 and 0zsimeq 2, at present one could ask what kind of reionization processes are allowed by present cosmic microwave background temperature and polarization measurements. An early contribution to reionization could imply a departure from the standard picture where star formation determines the reionization onset. By considering a broad class of possible reionization parameterizations, we find that current data do not require an early reionization component in our universe and that only one marginal class of models, based on a particular realization of reionization, may point to that. In addition, the frequentist Akaike information criterion (AIC) provides strong evidence against alternative reionization histories, favoring the most simple reionization scenario, which describes reionization by means of only one (constant) reionization optical depth τ.

  20. Was there an early reionization component in our universe?

    Energy Technology Data Exchange (ETDEWEB)

    Villanueva-Domingo, Pablo; Gariazzo, Stefano; Gnedin, Nickolay Y.; Mena, Olga

    2018-04-01

    A deep understanding of the Epoch of Reionization is still missing in our knowledge of the universe. While future probes will allow us to test the precise evolution of the free electron fraction from redshifts between $z\\simeq 6$ and $z\\simeq 20$, at present one could ask what kind of reionization processes are allowed by present Cosmic Microwave Background temperature and polarization measurements. An early contribution to reionization could imply a departure from the standard picture where star formation determines the reionization onset. BBy considering a broad class of possible reionization parameterizations, we find that current data do not require an early reionization component in our universe and that only one marginal class of models, based on a particular realization of reionization, may point to that. In addition, the frequentist Akaike Information Criterion (AIC) provides strong evidence against alternative reionization histories, favoring the most simple reionization scenario, which describes reionization by means of only one (constant) reionization optical depth $\\tau$.

  1. Parastatistics and the equation of state for the early universe

    International Nuclear Information System (INIS)

    Aldrovandi, R.; Monte Lima, I. do.

    1982-01-01

    The equation of state for an ideal mixture of relativistic quantum gases obeying any (para-) statistics is given. Recursion formulas are obtained for the distribution functions and correlations are analysed. The equation of state can be applied to the early Universe, allowing the quarks to be treated either as coloured fermions of (unequivalently) as parafermions of order 3. In the latter case, a tendency to aggregate into triads by a mere statistical effect is exhibited. (Author) [pt

  2. Generic features of vacuum phase transitions in the early universe

    International Nuclear Information System (INIS)

    Kephart, T.W.; Weiler, T.J.; Yuan, T.C.

    1990-01-01

    A simple Higgs model is utilized to show the occurrence of a four-phase pattern of vacuum symmetry. As temperature changes, an interplay of spontaneous symmetry breaking and spontaneous symmetry restoration ensues, and resonant field interchange occurs. The generality of models which may contain a sequence of vacuum phase transitions is emphasized. The laboratory for these multi-phase transitions is the early Universe. (orig.)

  3. Green's function for the scalar field in the early Universe

    International Nuclear Information System (INIS)

    Chowdhury, A.; Mallik, S.

    1987-01-01

    We derive the thermal Green's function for the scalar field in a de Sitter space-time and apply it to the problem of the early Universe. Field fluctuations relevant for inflation arise predominantly from wavelengths of the order of the inverse Hubble constant. Sufficient inflation is obtained in a Coleman-Weinberg model, provided the coupling constant is small enough. The results are insensitive to the choice of the vacuum of the field theory

  4. A Physical – Geometrical Model of an Early Universe

    Directory of Open Access Journals (Sweden)

    Corneliu BERBENTE

    2014-12-01

    Full Text Available A physical-geometrical model for a possible early universe is proposed. One considers an initial singularity containing the energy of the whole universe. The singularity expands as a spherical wave at the speed of light generating space and time. The relations of the special theory of relativity, quantum mechanics and gas kinetics are considered applicable. A structuring of the primary wave is adopted on reasons of geometrical simplicity as well as on satisfying the conservation laws. The evolution is able to lead to particles very close to neutrons as mass and radius. The actually admitted values for the radius and mass of the universe as well as the temperature of the ground radiation (3-5 K can be obtained by using the proposed model.

  5. The cosmological slingshot scenario: a stringy early times universe

    Energy Technology Data Exchange (ETDEWEB)

    Germani, Cristiano [D.A.M.T.P., Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Grandi, Nicolas [SISSA, via Beirut 4, 34014 Trieste (Italy); Kehagias, Alex [Physics Division, National Technical University of Athens, 15780 Zografou Campus, Athens (Greece)], E-mail: Germani@sissa.it, E-mail: grandi@fisica.unlp.edu.ar, E-mail: kehagias@central.ntua.gr

    2008-07-07

    A cosmological model for the early time universe is proposed. In this model, the universe is a wandering brane moving in a warped throat of a Calabi-Yau space. A nonzero angular momentum induces a turning point in the brane trajectory, and leads to a bouncing cosmology as experienced by an observer living on the brane. The universe undergoes a decelerated contraction followed by an accelerating expansion and no big-bang singularity. Although the number of e-folds of accelerated motion is low (less than 2), standard cosmological problems are not present in our model; thanks to the absence of an initial singularity and the violation of energy conditions of mirage matter at high energies. Density perturbations are also calculated in our model and we find a slightly red spectral index with negligible tensorial perturbations in compatibility with WMAP data.

  6. Feedback in low-mass galaxies in the early Universe.

    Science.gov (United States)

    Erb, Dawn K

    2015-07-09

    The formation, evolution and death of massive stars release large quantities of energy and momentum into the gas surrounding the sites of star formation. This process, generically termed 'feedback', inhibits further star formation either by removing gas from the galaxy, or by heating it to temperatures that are too high to form new stars. Observations reveal feedback in the form of galactic-scale outflows of gas in galaxies with high rates of star formation, especially in the early Universe. Feedback in faint, low-mass galaxies probably facilitated the escape of ionizing radiation from galaxies when the Universe was about 500 million years old, so that the hydrogen between galaxies changed from neutral to ionized-the last major phase transition in the Universe.

  7. Probing Models of Dark Matter and the Early Universe

    Science.gov (United States)

    Orlofsky, Nicholas David

    This thesis discusses models for dark matter (DM) and their behavior in the early universe. An important question is how phenomenological probes can directly search for signals of DM today. Another topic of investigation is how the DM and other processes in the early universe must evolve. Then, astrophysical bounds on early universe dynamics can constrain DM. We will consider these questions in the context of three classes of DM models--weakly interacting massive particles (WIMPs), axions, and primordial black holes (PBHs). Starting with WIMPs, we consider models where the DM is charged under the electroweak gauge group of the Standard Model. Such WIMPs, if generated by a thermal cosmological history, are constrained by direct detection experiments. To avoid present or near-future bounds, the WIMP model or cosmological history must be altered in some way. This may be accomplished by the inclusion of new states that coannihilate with the WIMP or a period of non-thermal evolution in the early universe. Future experiments are likely to probe some of these altered scenarios, and a non-observation would require a high degree of tuning in some of the model parameters in these scenarios. Next, axions, as light pseudo-Nambu-Goldstone bosons, are susceptible to quantum fluctuations in the early universe that lead to isocurvature perturbations, which are constrained by observations of the cosmic microwave background (CMB). We ask what it would take to allow axion models in the face of these strong CMB bounds. We revisit models where inflationary dynamics modify the axion potential and discuss how isocurvature bounds can be relaxed, elucidating the difficulties in these constructions. Avoiding disruption of inflationary dynamics provides important limits on the parameter space. Finally, PBHs have received interest in part due to observations by LIGO of merging black hole binaries. We ask how these PBHs could arise through inflationary models and investigate the opportunity

  8. EARLY OPTICAL OBSERVATIONS OF GAMMA-RAY BURSTS BY THE TAROT TELESCOPES: PERIOD 2001-2008

    International Nuclear Information System (INIS)

    Klotz, A.; Boer, M.; Atteia, J. L.; Gendre, B.

    2009-01-01

    The Telescopes a Action Rapide pour les Objets Transitoires telescopes are two robotic observatories designed to observe the prompt optical emission counterpart and the early afterglow of gamma-ray bursts (GRBs). We present data acquired between 2001 and 2008 and discuss the properties of the optical emission of GRBs, noting various interesting results. The optical emission observed during the prompt GRB phase is rarely very bright: we estimate that 5%-20% of GRBs exhibit a bright optical flash (R < 14) during the prompt gamma-ray emission, and that more than 50% of the GRBs have an optical emission fainter than R = 15.5 when the gamma-ray emission is active. We study the apparent optical brightness distribution of GRBs at 1000 s showing that our observations confirm the distribution derived by other groups. The combination of these results with those obtained by other rapid slewing telescopes allows us to better characterize the early optical emission of GRBs and to emphasize the importance of very early multiwavelength GRB studies for the understanding of the physics of the ejecta.

  9. Storage behavior of an early garlic (Allium sativum L.) subject to gamma-ray radioinhibition

    International Nuclear Information System (INIS)

    Croci, C.A.; Curzio, O.A.; Arguello, J.A.

    1990-01-01

    Garlic bulbs of an early cultivar (Rosado Paraguayo) were irradiated with a dose of 50 Gy of Co-60 gamma rays at 30 days after harvest. Experimental lots were stored up to 300 days in a commercial warehouse (6-32 degrees C; R.H. 40-50%). The treatment reduced the weight loss of the bulbs and increased the percentage of both marketable bulbs and cloves without affecting organoleptic properties. The results show that both the raw/fresh market for this early cultivar and the garlic processing industry would profit from the radioinhibition process

  10. Study Protocol: Early Stereotactic Gamma Knife Radiosurgery to Residual Tumor After Surgery of Newly Diagnosed Glioblastoma (Gamma-GBM).

    Science.gov (United States)

    Brehmer, Stefanie; Grimm, Mario Alexander; Förster, Alex; Seiz-Rosenhagen, Marcel; Welzel, Grit; Stieler, Florian; Wenz, Frederik; Groden, Christoph; Mai, Sabine; Hänggi, Daniel; Giordano, Frank Anton

    2018-04-24

    Glioblastoma (GBM) is the most common malignant brain tumor in adult patients. Tumor recurrence commonly occurs around the resection cavity, especially after subtotal resection (STR). Consequently, the extent of resection correlates with overall survival (OS), suggesting that depletion of postoperative tumor remnants will improve outcome. To assess safety and efficacy of adding stereotactic radiosurgery (SRS) to the standard treatment of GBM in patients with postoperative residual tumor. Gamma-GBM is a single center, open-label, prospective, single arm, phase II study that includes patients with newly diagnosed GBM (intraoperative via frozen sections) who underwent STR (residual tumor will be identified by native and contrast enhanced T1-weighted magnetic resonance imaging scans). All patients will receive SRS with 15 Gy (prescribed to the 50% isodose enclosing all areas of residual tumor) early (within 24-72 h) after surgery. Thereafter, all patients undergo standard-of-care therapy for GBM (radiochemotherapy with 60 Gy external beam radiotherapy [EBRT] plus concomitant temozolomide and 6 cycles of adjuvant temozolomide chemotherapy). The primary outcome is median progression-free survival, secondary outcomes are median OS, occurrence of radiation induced acute (3 mo post-SRS) neurotoxicity and incidence of symptomatic radionecrosis. We expect to detect efficacy and safety signals by the immediate application of SRS to standard-of-care therapy in newly diagnosed GBM. Early postoperative SRS to areas of residual tumor could bridge the therapeutic gap between surgery and adjuvant therapies.

  11. Gamma rays role in the improvement of yield and early maturity in soybean

    International Nuclear Information System (INIS)

    Moualla, M.Y.; Ali, N.M.

    1995-01-01

    Seeds from soybean variety glycine max (L) Merr., were irradiated with three doses of gamma rays: 100, 150 and 200 Gray in order to obtain high yielding and early maturity mutants to grown after wheat in a two crop rotation. All the three doses induced morphological and physiological variation and malformation that increased with increasing the dose. Coefficient of variation values were higher in M2 than in their respective values of M3. The results showed no selection efficiency under the non optimal environmental growing conditions with this lack of efficiency being more evident for yield than for early maturity. Using FTAB statistical programme 20 M2 and M3 plant were selected for each character and when evaluated in the following generation, it was clear that selection efficiency was higher for early maturity than for yield; the latter being high yielding and 4 early maturing m 4 mutants were obtained. 3 tabs

  12. Gamma rays role in the improvement of yield and early maturity in soybean

    Energy Technology Data Exchange (ETDEWEB)

    Moualla, M Y; Ali, N M [Atomic Energy Commission, P.O.Box 6091, Damascus (Syrian Arab Republic)

    1995-10-01

    Seeds from soybean variety glycine max (L) Merr., were irradiated with three doses of gamma rays: 100, 150 and 200 Gray in order to obtain high yielding and early maturity mutants to grown after wheat in a two crop rotation. All the three doses induced morphological and physiological variation and malformation that increased with increasing the dose. Coefficient of variation values were higher in M2 than in their respective values of M3. The results showed no selection efficiency under the non optimal environmental growing conditions with this lack of efficiency being more evident for yield than for early maturity. Using FTAB statistical programme 20 M2 and M3 plant were selected for each character and when evaluated in the following generation, it was clear that selection efficiency was higher for early maturity than for yield; the latter being high yielding and 4 early maturing m 4 mutants were obtained. 3 tabs.

  13. Exploring the Extreme Universe with the Fermi Gamma-Ray Space Telescope

    Science.gov (United States)

    Thompson, David J.; Digel, Seth W.; Racusin, Judith L.

    2012-01-01

    In ways similar to experiments in nuclear and particle physics, high-energy astrophysics usesgamma rays and energetic charged particles toprobe processes that involve large energy transfers.Since its launch in 2008, the international Fermi Gamma-Ray Space Telescope has been exploringnatural particle accelerators and the interactionsof high-energy particles in the universe. Withsources ranging from thunderstorms on Earth to galaxies and exploding stars in distant parts of the cosmos, the telescopes subjects of study are almostas diverse as were those of the scientist whose name it bears.

  14. Social anxiety and negative early life events in university students.

    Science.gov (United States)

    Binelli, Cynthia; Ortiz, Ana; Muñiz, Armando; Gelabert, Estel; Ferraz, Liliana; S Filho, Alaor; Crippa, José Alexandre S; Nardi, Antonio E; Subirà, Susana; Martín-Santos, Rocío

    2012-06-01

    There is substantial evidence regarding the impact of negative life events during childhood on the aetiology of psychiatric disorders. We examined the association between negative early life events and social anxiety in a sample of 571 Spanish University students. In a cross-sectional survey conducted in 2007, we collected data through a semistructured questionnaire of sociodemographic variables, personal and family psychiatric history, and substance abuse. We assessed the five early negative life events: (i) the loss of someone close, (ii) emotional abuse, (iii) physical abuse, (iv) family violence, and (v) sexual abuse. All participants completed the Liebowitz Social Anxiety Scale. Mean (SD) age was 21 (4.5), 75% female, LSAS score was 40 (DP = 22), 14.2% had a psychiatric family history and 50.6% had negative life events during childhood. Linear regression analyses, after controlling for age, gender, and family psychiatric history, showed a positive association between family violence and social score (p = 0.03). None of the remaining stressors produced a significant increase in LSAS score (p > 0.05). University students with high levels of social anxiety presented higher prevalence of negative early life events. Thus, childhood family violence could be a risk factor for social anxiety in such a population.

  15. The opacity of the universe for high and very high energy {gamma}-rays

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Manuel

    2013-08-15

    The flux of high energy (HE, energy 100 MeVor similar 100 GeV) {gamma}-rays originating from cosmological sources is attenuated due to pair production in interactions with photons at ultraviolet to infrared wavelengths of the extragalactic background light (EBL). The main components contributing to the EBL photon density are the starlight integrated over cosmic time and the starlight reprocessed by dust in galaxies. Consequently, the EBL is an integral measure of the cosmic star formation history. Depending on the source distance, the Universe should be opaque to {gamma}-rays above a certain energy. Nevertheless, the number of detected {gamma}-ray sources has increased continuously in recent years. VHE emitting objects beyond redshifts of z>0.5 have been detected with imaging air Cherenkov telescopes (IACTs), while HE {gamma}-rays from active galactic nuclei (AGN) above redshifts z>or similar 3 have been observed with the Large Area Telescope (LAT) on board the Fermi satellite. In this work, a large sample of VHE {gamma}-ray spectra will be combined with data of the Fermi-LAT to derive upper limits on the EBL photon density at z = 0. Generic EBL realizations are used to correct AGN spectra for absorption, which are subsequently tested against model assumptions. The evolution of the EBL with redshift is accounted for, and a possible formation of electromagnetic cascades is considered. As a result, the EBL density is constrained over almost three orders of magnitude in wavelength, between 0.4 {mu}m and 100 {mu}m. At optical wavelengths, an EBL intensity above 24 nW m{sup -2}sr{sup -1} is ruled out, and between 8 {mu}m and 31 {mu}m it is limited to be below 5 nW m{sup -2}sr{sup -1}. In the infrared, the constraints are within a factor {proportional_to} 2 of lower limits derived from galaxy number counts. Additionally,the behavior of VHE spectra in the transition from the optical depth regimes {tau

  16. Abnormal early gamma responses to emotional faces differentiate unipolar from bipolar disorder patients.

    Science.gov (United States)

    Liu, T Y; Chen, Y S; Su, T P; Hsieh, J C; Chen, L F

    2014-01-01

    This study investigates the cortical abnormalities of early emotion perception in patients with major depressive disorder (MDD) and bipolar disorder (BD) using gamma oscillations. Twenty-three MDD patients, twenty-five BD patients, and twenty-four normal controls were enrolled and their event-related magnetoencephalographic responses were recorded during implicit emotional tasks. Our results demonstrated abnormal gamma activity within 100 ms in the emotion-related regions (amygdala, orbitofrontal (OFC) cortex, anterior insula (AI), and superior temporal pole) in the MDD patients, suggesting that these patients may have dysfunctions or negativity biases in perceptual binding of emotional features at very early stage. Decreased left superior medial frontal cortex (smFC) responses to happy faces in the MDD patients were correlated with their serious level of depression symptoms, indicating that decreased smFC activity perhaps underlies irregular positive emotion processing in depressed patients. In the BD patients, we showed abnormal activation in visual regions (inferior/middle occipital and middle temporal cortices) which responded to emotional faces within 100 ms, supporting that the BD patients may hyperactively respond to emotional features in perceptual binding. The discriminant function of gamma activation in the left smFC, right medial OFC, right AI/inferior OFC, and the right precentral cortex accurately classified 89.6% of patients as unipolar/bipolar disorders.

  17. Annihilation and gravitational clumping of monopoles in the early universe

    International Nuclear Information System (INIS)

    Izawa, Mizuo; Sato, Katsuhiko.

    1983-01-01

    In order to avoid the overproduction of magnetic monopoles in the early Universe, we investigate how monopoles evolve in the Big Bang Universe for arbitrary mass of monopoles and the arbitrary initial abundance. First, we calculate pair annihilation of monopoles by taking into account the entropy production due to the annihilations. Second, we investigate the formation of monopole stars and black holes due to gravitational clumping of monopoles. In particular, we take into account the entropy and baryon number generation by black hole evaporation. It is shown, however, that the burning of monopole stars or the evaporation of black holes cannot dilute the monopole abundance sufficiently without conflicts with present baryon/entropy ratio and primordial nucleosynthesis regardless of monopole mass. (author)

  18. CP-Violating solitons in the early universe

    International Nuclear Information System (INIS)

    Tornkvist, O.; Riotto, A.

    1997-07-01

    Solitons in extensions of the Standard Model can serve as localized sources of CP violation. Depending on their stability properties, they may serve either to create or to deplete the baryon asymmetry. The conditions for existence of a particular soliton candidate, the membrane solution of the two-Higgs model, are presented. In the generic case, investigated by Bachas and Tomaras, membranes exist and are metastable for a wide range of parameters. For the more viable supersymmetric case, it is shown that the present-day existence of CP-violating membranes is experimentally excluded, but preliminary studies suggest that they may have existed in the early universe soon after the electroweak phase transition, with important consequences for the baryon asymmetry of the universe

  19. Anisotropic to Isotropic Phase Transitions in the Early Universe

    Directory of Open Access Journals (Sweden)

    Ajaib M. A.

    2012-04-01

    Full Text Available We attempt to develop a minimal formalism to describe an anisotropic to isotropic tran- sition in the early Universe. Assuming an underlying theory that violates Lorentz in- variance, we start with a Dirac like equation, involving four massless fields, and which does not exhibit Lorentz invariance. We then perform transformations that restore it to its covariant form along with a mass term for the fermion field. It is proposed that these transformations can be visualized as waves traveling in an anisotropic media. The trans- formation it = ℏ ! is then utilized to transit to a statistical thermodynamics system and the partition function then gives a better insight into the character of this transition. The statistical system hence realized is a two level system with each state doubly degenerate. We propose that modeling the transition this way can help explain the matter antimatter asymmetry of the Universe.

  20. Resonant Production of Sterile Neutrinos in the Early Universe

    Science.gov (United States)

    Gilbert, Lauren; Grohs, Evan; Fuller, George M.

    2016-06-01

    This study examines the cosmological impacts of a light resonantly produced sterile neutrino in the early universe. Such a neutrino could be produced through lepton number-driven Mikheyev-Smirnov-Wolfenstein (MSW) conversion of active neutrinos around big bang nucleosynthesis (BBN), resulting in a non-thermal spectrum of both sterile and electron neutrinos. During BBN, the neutron-proton ratio depends sensitively on the electron neutrino flux. If electron neutrinos are being converted to sterile neutrinos, this makes the n/p ratio a probe of possible new physics. We use observations of primordial Yp and D/H to place limits on this process.

  1. Early universe cosmology and tests of fundamental physics

    International Nuclear Information System (INIS)

    Albrecht, Andreas; Frieman, Joshua A.; Trodden, Mark

    2002-01-01

    This is the report of the Working Group on Early Universe Cosmology and tests of Fundamental Physics, group P4.8 of the of the Snowmass 2001 conference. Here we summarize the impressive array of advances that have taken place in this field, and identify opportunities for even greater progress in the future. Topics include Dark Energy, Cosmic Acceleration, Inflation, Phase Transitions, Baryogenesis, and String/M-theory Cosmology. The introductory section gives an executive summary with six key open questions on which we can expect to make significant progress

  2. The Origin of Dust in the Early Universe

    Science.gov (United States)

    Dwek, Eli

    2011-01-01

    In this talk I will describe the origin of dust in the early universe. I will be presenting observations of the spectral energy distribution of the galaxy J1148+5251, and present estimates of the dust mass in this high redshift (z=6.4) object. I will then discuss the origin of this dust, and the role of SN and AGB stars as dust sources, and the effect of SNRs on the destruction of dust in the interstellar medium of this galaxy.

  3. Sentinel node localisation using pre-operative lymphoscintigraphy and intraoperative gamma probe in early oral cavity cancer

    International Nuclear Information System (INIS)

    Ikram, M.; Akhtar, S.; Junaid, M.; Dhari, T.; Zaman, M.U.; Hussain, R.

    2013-01-01

    Objectives: To assess the diagnostic value of sentinel lymph node localisation using pre-operative lymphoscintigraphy and intra-operative gamma probe radio localisation in Pakistani patients suffering from early stage squamous cell carcinoma of the oral cavity. Methods: The prospective case series was conducted between September 2007 and April 2010 at the Aga Khan University Hospital, Karachi. It comprised patients with T1 and T2 oral cavity cancer with clinically and radiologically negative neck. Pre-operative lymphoscintigraphy was performed one day before surgery and intra-operative gamma probe was used to detect sentinel node. Final histo-pathological evaluation was taken as the gold standard. Results: The study comprised 42 patients: 32(76%) males and 10(24%) females. The primary tumour site was buccal mucosa in 25 (60%) patients, and tongue in 17 (40%). Sentinel lymph node was detected in 38 (90%) patients. On final histopathological identification, 7 (17%) patients had cancer in the neck nodes. In all patients with metastasis, sentinel lymph node technique correctly identified the involved neck level. None of the patients revealed metastasis in non-sentinel lymph nodes. Conclusion:Evidence suggested the use of sentinel node biopsy in patients with head and neck squamous cell carcinoma. (author)

  4. The Transient High-Energy Sky and Early Universe Surveyor (THESEUS)

    Science.gov (United States)

    Amati, L.; O'Brien, P.; Goetz, D.; Tenzer, C.; Bozzo, E.

    2017-10-01

    The Transient High Energy Sky and Early Universe Surveyor (THESEUS) is a mission concept developed by a large international collaboration aimed at exploiting Gamma-Ray Bursts for investigating the early Universe. The main scientic objectives of THESEUS, currently under evaluation by ESA within the selection process for next M5 mission, include: investigating the star formation rate and metallicity evolution of the ISM and IGM up to redshift 10, detecting the first generation (pop III) of stars, studying the sources and physics of re-ionization, detecting the faint end of galaxies luminosity function. These goals will be achieved through a unique combination of instruments allowing GRB detection and arcmin localization over a broad FOV (more than 1sr) and an energy band extending from several MeVs down to 0.3 keV with unprecedented sensitivity, as well as on-board prompt (few minutes) follow-up with a 0.7m class IR telescope with both imaging and spectroscopic capabilities. Such instrumentation will also allow THESEUS to perform a monitoring of the X-ray sky with unprecedented sensitivity, which will provide a perfect service and sinergy to next generation multi-wavalength (e.g., E-ELT, SKA, CTA, ATHENA) and multi-messenger (aLIGO, aVIRGO, eLISA, ET, neutrino detectors, ...) facilities.

  5. Effects of gamma ray irradiation on early growth of soybean (Glycine mac (L). Merrill)

    International Nuclear Information System (INIS)

    Lilik Harsanti; Yulidar

    2015-01-01

    Increase my in domestic soybean production is one of the government's program to reduce dependence on imported soybeans and soybean efforts to achieve self-sufficiency in 2015. An experiment has been conducted to study the effects of gamma ray irradiation of of 60 Cobalt on early growth of soybean seed. Variety Denna 2 varieties have been irradiated by gamma rays with 0 Gy, 200 Gy, 300 Gy, 400 Gy doses, and then planted in green house on Ps Jumat PAIR-BATAN. Plant growth from each doses is proved to be varied. From germination viability on the third day, the highest percentage of seedling with leaves is on 100 Gy dose (73.75%), and 7, 14 and 21 day the lowest is on dose 400 Gy. (author)

  6. Universal biology and the statistical mechanics of early life

    Science.gov (United States)

    Goldenfeld, Nigel; Biancalani, Tommaso; Jafarpour, Farshid

    2017-11-01

    All known life on the Earth exhibits at least two non-trivial common features: the canonical genetic code and biological homochirality, both of which emerged prior to the Last Universal Common Ancestor state. This article describes recent efforts to provide a narrative of this epoch using tools from statistical mechanics. During the emergence of self-replicating life far from equilibrium in a period of chemical evolution, minimal models of autocatalysis show that homochirality would have necessarily co-evolved along with the efficiency of early-life self-replicators. Dynamical system models of the evolution of the genetic code must explain its universality and its highly refined error-minimization properties. These have both been accounted for in a scenario where life arose from a collective, networked phase where there was no notion of species and perhaps even individuality itself. We show how this phase ultimately terminated during an event sometimes known as the Darwinian transition, leading to the present epoch of tree-like vertical descent of organismal lineages. These examples illustrate concrete examples of universal biology: the quest for a fundamental understanding of the basic properties of living systems, independent of precise instantiation in chemistry or other media. This article is part of the themed issue 'Reconceptualizing the origins of life'.

  7. Structure in the early afterglow light curve of the gamma-ray burst of 29 March 2003.

    Science.gov (United States)

    Uemura, Makoto; Kato, Taichi; Ishioka, Ryoko; Yamaoka, Hitoshi; Monard, Berto; Nogami, Daisaku; Maehara, Hiroyuki; Sugie, Atsushi; Takahashi, Susumu

    2003-06-19

    Gamma-ray bursts (GRBs) are energetic explosions that for 0.01-100 s are the brightest gamma-ray sources in the sky. Observations of the early evolution of afterglows are expected to provide clues about the nature of the bursts, but their rapid fading has hampered such studies; some recent rapid localizations of bursts have improved the situation. Here we report an early detection of the very bright afterglow of the burst of 29 March 2003 (GRB030329). Our data show that, even early in the afterglow phase, the light curve shows unexpectedly complicated structures superimposed on the fading background.

  8. FERMI LARGE AREA TELESCOPE CONSTRAINTS ON THE GAMMA-RAY OPACITY OF THE UNIVERSE

    International Nuclear Information System (INIS)

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Allafort, A.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Atwood, W. B.; Baldini, L.; Bellazzini, R.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Baughman, B. M.; Bhat, P. N.; Bonamente, E.

    2010-01-01

    The extragalactic background light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ∼10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the γ-ray flux of extragalactic sources such as blazars and gamma-ray bursts (GRBs). The Large Area Telescope on board Fermi detects a sample of γ-ray blazars with redshift up to z ∼ 3, and GRBs with redshift up to z ∼ 4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of γ-ray flux attenuation by the EBL. We place upper limits on the γ-ray opacity of the universe at various energies and redshifts and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the 'baseline' model of Stecker et al. can be ruled out with high confidence.

  9. One-loop quantum gravity repulsion in the early Universe.

    Science.gov (United States)

    Broda, Bogusław

    2011-03-11

    Perturbative quantum gravity formalism is applied to compute the lowest order corrections to the classical spatially flat cosmological Friedmann-Lemaître-Robertson-Walker solution (for the radiation). The presented approach is analogous to the approach applied to compute quantum corrections to the Coulomb potential in electrodynamics, or rather to the approach applied to compute quantum corrections to the Schwarzschild solution in gravity. In the framework of the standard perturbative quantum gravity, it is shown that the corrections to the classical deceleration, coming from the one-loop graviton vacuum polarization (self-energy), have (UV cutoff free) opposite to the classical repulsive properties which are not negligible in the very early Universe. The repulsive "quantum forces" resemble those known from loop quantum cosmology.

  10. The early universe: facts and fiction (astronomy and astrophysics library)

    CERN Document Server

    Börner, Gerhard

    2013-01-01

    This fourth edition of Börner's "The Early Universe" is practically a new book, not just updated version. In particular, it is now organized so as to make it more useful as a textbook. And problem sections are also added. In the centre are the connections between particle physics and cosmology: The standard model, some basic implications of quantum field theory and the questions of structure formation. Special emphasis is given to the observed anisotropies of the cosmic microwave background and the consequences drawn for cosmology and for the structure formation models. Nuclear and particle physicists and astrophysicists, researchers and teachers as well as graduate students will welcome this new edition of a classic text and reference.

  11. On Effective Degrees of Freedom in the Early Universe

    Directory of Open Access Journals (Sweden)

    Lars Husdal

    2016-12-01

    Full Text Available We explore the effective degrees of freedom in the early Universe, from before the electroweak scale at a few femtoseconds after the Big Bang until the last positrons disappeared a few minutes later. We look at the established concepts of effective degrees of freedom for energy density, pressure, and entropy density, and introduce effective degrees of freedom for number density as well. We discuss what happens with particle species as their temperature cools down from relativistic to semi- and non-relativistic temperatures, and then annihilates completely. This will affect the pressure and the entropy per particle. We also look at the transition from a quark-gluon plasma to a hadron gas. Using a list a known hadrons, we use a “cross-over” temperature of 214 MeV, where the effective degrees of freedom for a quark-gluon plasma equals that of a hadron gas.

  12. Mutated hilltop inflation: a natural choice for early universe

    International Nuclear Information System (INIS)

    Pal, Barun Kumar; Pal, Supratik; Basu, B.

    2010-01-01

    We propose a model of inflation with a suitable potential for a single scalar field which falls in the wide class of hilltop inflation. We derive the analytical expressions for most of the physical quantities related to inflation and show that all of them represent the true behavior as required from a model of inflation. We further subject the results to observational verification by formulating the theory of perturbations based on our model followed by an estimation for the values of those observable parameters. Our model is found to be in excellent agreement with observational data. Thus, the features related to the model leads us to infer that this type of hilltop inflation may be a natural choice for explaining the early universe

  13. Primordial Black Holes from Supersymmetry in the Early Universe.

    Science.gov (United States)

    Cotner, Eric; Kusenko, Alexander

    2017-07-21

    Supersymmetric extensions of the standard model generically predict that in the early Universe a scalar condensate can form and fragment into Q balls before decaying. If the Q balls dominate the energy density for some period of time, the relatively large fluctuations in their number density can lead to formation of primordial black holes (PBH). Other scalar fields, unrelated to supersymmetry, can play a similar role. For a general charged scalar field, this robust mechanism can generate black holes over the entire mass range allowed by observational constraints, with a sufficient abundance to account for all dark matter in some parameter ranges. In the case of supersymmetry the mass range is limited from above by 10^{23}  g. We also comment on the role that topological defects can play for PBH formation in a similar fashion.

  14. Parametric Resonance in the Early Universe - A Fitting Analysis

    CERN Document Server

    Figueroa, Daniel G.

    2017-02-01

    Particle production via parametric resonance in the early Universe, is a non-perturbative, non-linear and out-of-equilibrium phenomenon. Although it is a well studied topic, whenever a new scenario exhibits parametric resonance, a full re-analysis is normally required. To avoid this tedious task, many works present often only a simplified linear treatment of the problem. In order to surpass this circumstance in the future, we provide a fitting analysis of parametric resonance through all its relevant stages: initial linear growth, non-linear evolution, and relaxation towards equilibrium. Using lattice simulations in an expanding grid in $3+1$ dimensions, we parametrise the dynamics' outcome scanning over the relevant ingredients: role of the oscillatory field, particle coupling strength, initial conditions, and background expansion rate. We emphasise the inaccuracy of the linear calculation of the decay time of the oscillatory field, and propose a more appropriate definition of this scale based on the subsequ...

  15. The determination of the thermal neutron and gamma fluxes at the Maryland University Training Reactor using thermoluminescent dosimetry

    International Nuclear Information System (INIS)

    Karceski, Jeffrey David; Ebert, David D.; Munno, Frank J.

    1988-01-01

    Determination of the dose received by a material in a mixed gamma and neutron field is of paramount concern to any research reactor owner. This dose can be separated into three distinguishable parts using standard thermoluminescent dosimetry (TLD) responses: 1) thermal neutron dose, 2) fission gamma dose, and 3) fission product gamma dose. For the Maryland University Training Reactor (MUTR), these respective fluences were determined for each of the associated experimental facilities. Quantifying the magnitude of the gamma and thermal neutron exposures at various reactor power levels was accomplished using Li-6F and Li-7F TLDs, respectively. These two types of dosimetry were chosen given the following considerations: 1) there is no existing standard established for fluence determination in a mixed field, 2) the LiF TLDs have a wide range of sensitivity to radiation, from 0.01 mR to 10,000 R, and 3) LiF TLDs are easy to read given the proper equipment. Standardization of the gamma/neutron doses was accomplished using the 500,000 Rad/hr Co-60 gamma source also located at the University of Maryland. (author)

  16. Magnetic fields and chiral asymmetry in the early hot universe

    International Nuclear Information System (INIS)

    Sydorenko, Maksym; Shtanov, Yuri; Tomalak, Oleksandr

    2016-01-01

    In this paper, we study analytically the process of external generation and subsequent free evolution of the lepton chiral asymmetry and helical magnetic fields in the early hot universe. This process is known to be affected by the Abelian anomaly of the electroweak gauge interactions. As a consequence, chiral asymmetry in the fermion distribution generates magnetic fields of non-zero helicity, and vice versa. We take into account the presence of thermal bath, which serves as a seed for the development of instability in magnetic field in the presence of externally generated lepton chiral asymmetry. The developed helical magnetic field and lepton chiral asymmetry support each other, considerably prolonging their mutual existence, in the process of 'inverse cascade' transferring magnetic-field power from small to large spatial scales. For cosmologically interesting initial conditions, the chiral asymmetry and the energy density of helical magnetic field are shown to evolve by scaling laws, effectively depending on a single combined variable. In this case, the late-time asymptotics of the conformal chiral chemical potential reproduces the universal scaling law previously found in the literature for the system under consideration. This regime is terminated at lower temperatures because of scattering of electrons with chirality change, which exponentially washes out chiral asymmetry. We derive an expression for the termination temperature as a function of the chiral asymmetry and energy density of helical magnetic field.

  17. Magnetic fields and chiral asymmetry in the early hot universe

    Energy Technology Data Exchange (ETDEWEB)

    Sydorenko, Maksym; Shtanov, Yuri [Bogolyubov Institute for Theoretical Physics, 03680 Kiev (Ukraine); Tomalak, Oleksandr, E-mail: maxsydorenko@gmail.com, E-mail: tomalak@uni-mainz.de, E-mail: shtanov@bitp.kiev.ua [Institut für Kernphysik, Johannes Gutenberg Universität, 55128 Mainz (Germany)

    2016-10-01

    In this paper, we study analytically the process of external generation and subsequent free evolution of the lepton chiral asymmetry and helical magnetic fields in the early hot universe. This process is known to be affected by the Abelian anomaly of the electroweak gauge interactions. As a consequence, chiral asymmetry in the fermion distribution generates magnetic fields of non-zero helicity, and vice versa. We take into account the presence of thermal bath, which serves as a seed for the development of instability in magnetic field in the presence of externally generated lepton chiral asymmetry. The developed helical magnetic field and lepton chiral asymmetry support each other, considerably prolonging their mutual existence, in the process of 'inverse cascade' transferring magnetic-field power from small to large spatial scales. For cosmologically interesting initial conditions, the chiral asymmetry and the energy density of helical magnetic field are shown to evolve by scaling laws, effectively depending on a single combined variable. In this case, the late-time asymptotics of the conformal chiral chemical potential reproduces the universal scaling law previously found in the literature for the system under consideration. This regime is terminated at lower temperatures because of scattering of electrons with chirality change, which exponentially washes out chiral asymmetry. We derive an expression for the termination temperature as a function of the chiral asymmetry and energy density of helical magnetic field.

  18. Star Formation-Driven Winds in the Early Universe

    Science.gov (United States)

    Peek, Matthew; Lundgren, Britt; Brammer, Gabriel

    2018-01-01

    Measuring the extent of star formation-driven winds from galaxies in the early universe is crucial for understanding of how galaxies evolve over cosmic time. Using WFC3/IR grism data from the Hubble Space Telescope (HST), we have measured the star formation rates and star formation rate surface densities of several hundred galaxies at redshift (z) = 1, when the universe was roughly half its present age. The galaxies we examine are also probed by background quasars, whose spectra provide information about the extent of metal-enriched gas in their halos. We use a computational pipeline to measure the density of the star formation in each galaxy and correlate these measurements with detections of Mg II absorption in nearby quasar spectra from the Sloan Digital Sky Survey. Our preliminary results support a model in which galaxies with high SFR surface densities drive metal-enriched gas out of the disk and into these galaxies’ extended halos, where that gas is detected in the spectra of more distant quasars.

  19. A Glimpse of the Very Early Universal Web

    Science.gov (United States)

    2001-05-01

    The VLT Maps Extremely Distant Galaxies Summary New, trailblazing observations with the ESO Very Large Telescope (VLT) at Paranal lend strong support to current computer models of the early universe: It is "spongy", with galaxies forming along filaments, like droplets along the strands of a spiders web. A group of astronomers at ESO and in Denmark [1] determined the distances to some very faint galaxies in the neighbourhood of a distant quasar. Plotting their positions in a three-dimensional map, they found that these objects are located within a narrow "filament", exactly as predicted by the present theories for the development of the first structures in the young universe . The objects are most likely "building blocks" from which galaxies and clusters of galaxies assemble. This observation shows a very useful way forward for the study of the early evolution of the universe and the emergence of structures soon after the Big Bang. At the same time, it provides yet another proof of the great power of the new class of giant optical telescopes for cosmological studies. PR Photo 19a/01 : Web-like structures in the young Universe (computer model). PR Photo 19b/01 : A group of objects at redshift 3.04 . PR Photo 19c/01 : Animated view of sky field and distant filament . PR Photo 19d/01 : The shape of the filament . PR Photo 19e/01 : Artist's impression of the very distant filament. PR Video Clip 04/01 : Video animation of the very distant filament. The computers are ahead of the telescopes For the past two decades cosmologists have been in the somewhat odd situation that their computers were "ahead" of their telescopes. The rapid evolution of powerful computer hardware and sophisticated software has provided theorists with the ability to build almost any sort of virtual universe they can imagine. Starting with different initial conditions just after the Big Bang, they can watch such fictional worlds evolve over billions of years in their supercomputers - and do so in a

  20. Effects of twenty-minute 3G mobile phone irradiation on event related potential components and early gamma synchronization in auditory oddball paradigm.

    Science.gov (United States)

    Stefanics, G; Thuróczy, G; Kellényi, L; Hernádi, I

    2008-11-19

    We investigated the potential effects of 20 min irradiation from a new generation Universal Mobile Telecommunication System (UMTS) 3G mobile phone on human event related potentials (ERPs) in an auditory oddball paradigm. In a double-blind task design, subjects were exposed to either genuine or sham irradiation in two separate sessions. Before and after irradiation subjects were presented with a random series of 50 ms tone burst (frequent standards: 1 kHz, P=0.8, rare deviants: 1.5 kHz, P=0.2) at a mean repetition rate of 1500 ms while electroencephalogram (EEG) was recorded. The subjects' task was to silently count the appearance of targets. The amplitude and latency of the N100, N200, P200 and P300 components for targets and standards were analyzed in 29 subjects. We found no significant effects of electromagnetic field (EMF) irradiation on the amplitude and latency of the above ERP components. In order to study possible effects of EMF on attentional processes, we applied a wavelet-based time-frequency method to analyze the early gamma component of brain responses to auditory stimuli. We found that the early evoked gamma activity was insensitive to UMTS RF exposition. Our results support the notion, that a single 20 min irradiation from new generation 3G mobile phones does not induce measurable changes in latency or amplitude of ERP components or in oscillatory gamma-band activity in an auditory oddball paradigm.

  1. Microphysics and the evolution of the early universe

    International Nuclear Information System (INIS)

    Rothman, A.R.

    1981-01-01

    Four nonstandard cosmological models of the early Universe are investigated. The first considers the effects of anisotropy and dissipative effects on the baryon-to-photon ratio in the context of Grand Unified Theories. A detailed model of an anisotropic universe is developed and the Kolb-Wolfram equations governing baryosynthesis are evolved in this model. Contrary to recent claims of Bond, Kolb, and Silk, no limits are found on anisotropy during this epoch. The second investigation examines the effects caused by evaporating 10 10 gm primordial black holes on cosmic nucleosynthesis of the light elements. By requiring that the final deuterium produced by nucleosynthesis not be greater than 5 x 10 -5 parts by mass, it is found that rho/sub H//rho/sub b/ less than or equal to 10 -7 , where rho/sub H/ is the mass density of 10 10 gm black holes and rho/sub b/ is the mass density of baryons during nucleosynthesis. In the third chapter limits are placed on G/G by examining the effect a larger value of G in the past would have had on primordial nucleosynthesis. This is done by taking into account the new conservation laws and Einstein equations a variable-G theory would have. Assuming a power law for G, it is found that /G/G/ less than or equal to 1.7 x 10 -13 yr -1 . This result is approximately a factor of two stronger than limits found in naive models where the new conservation laws are not taken into account. The fourth investigation concerns the effects of anisotropy and dissipation on primordial nucleosynthesis. A detailed numerical model is developed. Contrary to models in which dissipation is not considered it is found that anisotropy in many cases actually lowers the final helium abundance

  2. Testing the Isotropic Universe Using the Gamma-Ray Burst Data of Fermi/GBM

    Science.gov (United States)

    Řípa, Jakub; Shafieloo, Arman

    2017-12-01

    The sky distribution of gamma-ray bursts (GRBs) has been intensively studied by various groups for more than two decades. Most of these studies test the isotropy of GRBs based on their sky number density distribution. In this work, we propose an approach to test the isotropy of the universe through inspecting the isotropy of the properties of GRBs such as their duration, fluences, and peak fluxes at various energy bands and different timescales. We apply this method on the Fermi/Gamma-ray Burst Monitor (GBM) data sample containing 1591 GRBs. The most noticeable feature we found is near the Galactic coordinates l≈ 30^\\circ , b≈ 15^\\circ , and radius r≈ 20^\\circ {--}40^\\circ . The inferred probability for the occurrence of such an anisotropic signal (in a random isotropic sample) is derived to be less than a percent in some of the tests while the other tests give results consistent with isotropy. These are based on the comparison of the results from the real data with the randomly shuffled data samples. Considering the large number of statistics we used in this work (some of which are correlated with each other), we can anticipate that the detected feature could be a result of statistical fluctuations. Moreover, we noticed a considerably low number of GRBs in this particular patch, which might be due to some instrumentation or observational effects that can consequently affect our statistics through some systematics. Further investigation is highly desirable in order to clarify this result, e.g., utilizing a larger future Fermi/GBM data sample as well as data samples of other GRB missions and also looking for possible systematics.

  3. Arteriovenous malformations of the brain treated with gamma knife; Early effects in 25 children

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Takayuki; Kobayashi, Tatsuya; Kida, Yoshihisa (Komaki City Hospital, Hokkaido (Japan))

    1994-02-01

    The early effects of treatment with gamma knife radiosurgery for intracranial arteriovenous malformations (AVM) were investigated in 25 children, 15 boys and 10 girls, aged 2 to 15 years (mean 11). Neurological signs were hemiparesis in 10, mental retardation in 2, etc. Initial events were hemorrhage in 23 (92%) and epilepsy in 2 patients. The locations of AVM were parietal lobe in 6, thalamus in 4 patients, etc. The mean diameter of the nidus was 1.97 cm, and the volume was under 10 cm[sup 3] in 21 cases. Of the 25 patients were classified as Grade II or higher by the Spetzler and Martin grading system. The mean maximum dose was 36.2 Gy, and marginal dose of 20.2 Gy with a mean isocenter of 3.2 were used. Follow-up angiography was performed more than one year after treatment in 7 patients. Five of the 7 (71.4%) showed complete obliteration of the AVM. No patients has had rebleeding after treatment so far, but one patient has had hemiparesis due to radiation-induced edema. Stereotactic radiosurgery by gamma knife is a preventive treatment of intracranial AVM in childhood. (author).

  4. Early universe with modified scalar-tensor theory of gravity

    Science.gov (United States)

    Mandal, Ranajit; Sarkar, Chandramouli; Sanyal, Abhik Kumar

    2018-05-01

    Scalar-tensor theory of gravity with non-minimal coupling is a fairly good candidate for dark energy, required to explain late-time cosmic evolution. Here we study the very early stage of evolution of the universe with a modified version of the theory, which includes scalar curvature squared term. One of the key aspects of the present study is that, the quantum dynamics of the action under consideration ends up generically with de-Sitter expansion under semiclassical approximation, rather than power-law. This justifies the analysis of inflationary regime with de-Sitter expansion. The other key aspect is that, while studying gravitational perturbation, the perturbed generalized scalar field equation obtained from the perturbed action, when matched with the perturbed form of the background scalar field equation, relates the coupling parameter and the potential exactly in the same manner as the solution of classical field equations does, assuming de-Sitter expansion. The study also reveals that the quantum theory is well behaved, inflationary parameters fall well within the observational limit and quantum perturbation analysis shows that the power-spectrum does not deviate considerably from the standard one obtained from minimally coupled theory.

  5. Probing the early universe with inflationary gravitational waves

    International Nuclear Information System (INIS)

    Boyle, Latham A.; Steinhardt, Paul J.

    2008-01-01

    Near comoving wave number k, the gravitational-wave background (GWB) from inflation carries information about the physical conditions near two moments in cosmic history: the moment when k 'left the horizon' during inflation, and the moment when it 're-entered the horizon' after inflation. We investigate the extent to which this information can be extracted if the GWB is measured by a combination of cosmic-microwave-background polarization experiments on large scales and space-based laser-interferometer experiments on small scales. To disentangle this information, we derive a new gravitational-wave transfer function that incorporates a number of physical effects that were treated less accurately, less generally, or were missing altogether in previous treatments. In particular, it incorporates: (i) dark energy with time-varying equation of state w(z); (ii) tensor anisotropic stress due to free-streaming relativistic particles in the early universe; and (iii) a variety of physical effects that cause deviations from the standard equation of state w=1/3 during the radiation era. Based on this transfer function, we consider the degree to which the GWB can be used to test inflation and to probe the 'primordial dark age' between the end of inflation and the electroweak phase transition.

  6. Turbulence of Weak Gravitational Waves in the Early Universe.

    Science.gov (United States)

    Galtier, Sébastien; Nazarenko, Sergey V

    2017-12-01

    We study the statistical properties of an ensemble of weak gravitational waves interacting nonlinearly in a flat space-time. We show that the resonant three-wave interactions are absent and develop a theory for four-wave interactions in the reduced case of a 2.5+1 diagonal metric tensor. In this limit, where only plus-polarized gravitational waves are present, we derive the interaction Hamiltonian and consider the asymptotic regime of weak gravitational wave turbulence. Both direct and inverse cascades are found for the energy and the wave action, respectively, and the corresponding wave spectra are derived. The inverse cascade is characterized by a finite-time propagation of the metric excitations-a process similar to an explosive nonequilibrium Bose-Einstein condensation, which provides an efficient mechanism to ironing out small-scale inhomogeneities. The direct cascade leads to an accumulation of the radiation energy in the system. These processes might be important for understanding the early Universe where a background of weak nonlinear gravitational waves is expected.

  7. GUTs and supersymmetric GUTs in the very early universe

    International Nuclear Information System (INIS)

    Ellis, J.

    1982-10-01

    This talk is intended as background material for many of the other talks treating the possible applications of GUTs to the very early universe. I start with a review of the present theoretical and phenomenological status of GUTs before going on to raise some new issues for their prospective cosmological applications which arise in supersymmetric (susy) GUTs. The first section is an update on conventional GUTs, which is followed by a reminder of some of the motivations for going supersymmetric. There then follows a simple primer on susy and a discussion of the structure and phenomenology of simple sysy GUTs. Finally we come to the cosmological issues, including problems arising from the degeneracy of susy minima, baryosynthesis and supersymmetric inflation, the possibility that gravity is an essential complication in constructing susy GUTs and discussing their cosmology, and the related question of what mass range is allowed for the gravitino. Several parts of this write-up contain new material which has emerged either during the Workshop or subsequently. They are included here for completeness and the convenience of the prospective reader. Wherever possible, these anachronisms will be flagged so as to keep straight the historical record

  8. Early detection of radioactive fall-out by gamma-spectrometry

    DEFF Research Database (Denmark)

    Aage, Helle Karina; Korsbech, Uffe C C; Bargholz, K.

    2003-01-01

    Radioactive fallout should be detected as early as possible. A new and efficient method for detection of low-level irradiation from manmade radioactivity is developed. Radiation abnormalities are detectable down to air kerma rate, of 0.5 to 1.0 nGy h(-1) for Cs-137 and even lower for I-131...... For multi-gamma energy radioactivity the detection level is 2.6-3.5 nGy h(-1). A standard NaI detector and a 512-channel analyser are used together with noise adjusted singular value decomposition (NASVD). Statistical noise is removed and the measured spectra are reproduced using spectral components...... radioactive sources need to be detected....

  9. Separating the early universe from the late universe: Cosmological parameter estimation beyond the black box

    International Nuclear Information System (INIS)

    Tegmark, Max; Zaldarriaga, Matias

    2002-01-01

    We present a method for measuring the cosmic matter budget without assumptions about speculative early Universe physics, and for measuring the primordial power spectrum P * (k) nonparametrically, either by combining CMB and LSS information or by using CMB polarization. Our method complements currently fashionable 'black box' cosmological parameter analysis, constraining cosmological models in a more physically intuitive fashion by mapping measurements of CMB, weak lensing and cluster abundance into k space, where they can be directly compared with each other and with galaxy and Lyα forest clustering. Including the new CBI results, we find that CMB measurements of P(k) overlap with those from 2dF galaxy clustering by over an order of magnitude in scale, and even overlap with weak lensing measurements. We describe how our approach can be used to raise the ambition level beyond cosmological parameter fitting as data improves, testing rather than assuming the underlying physics

  10. Ultra-Fast Flash Observatory: Fast Response Space Missions for Early Time Phase of Gamma Ray Bursts

    DEFF Research Database (Denmark)

    Park, I.H.; Ahmad, S.; Barrillon, P.

    2013-01-01

    One of the unexplored domains in the study of gamma-ray bursts (GRBs) is the early time phase of the optical light curve. We have proposed Ultra-Fast Flash Observatory (UFFO) to address this question through extraordinary opportunities presented by a series of small space missions. The UFFO...

  11. Pulsar-Driven Jets in Supernovae, Gamma-Ray Bursts, and the Universe

    Directory of Open Access Journals (Sweden)

    John Middleditch

    2012-01-01

    Full Text Available The bipolarity of Supernova 1987A can be understood through its very early light curve from the CTIO 0.4 m telescope and IUE FES and following speckle observations of the “Mystery Spot”. These indicate a beam/jet of light/particles, with initial collimation factors >104 and velocities >0.95 c, involving up to 10−5 M⊙ interacting with circumstellar material. These can be produced by a model of pulsar emission from polarization currents induced/(modulated faster than c beyond the pulsar light cylinder by the periodic electromagnetic field (supraluminally induced polarization currents (SLIP. SLIP accounts for the disruption of supernova progenitors and their anomalous dimming at cosmological distances, jets from Sco X-1 and SS 433, the lack/presence of pulsations from the high-/low-luminosity low-mass X-ray binaries, and long/short gamma-ray bursts, and it predicts that their afterglows are the pulsed optical-/near-infrared emission associated with these pulsars. SLIP may also account for the TeV e+/e− results from PAMELA and ATIC, the WMAP “Haze”/Fermi “Bubbles,” and the r-process. SLIP jets from SNe of the first stars may allow galaxies to form without dark matter and explain the peculiar nongravitational motions between pairs of distant galaxies observed by GALEX.

  12. Asymmetric Engagement of Amygdala and Its Gamma Connectivity in Early Emotional Face Processing

    Science.gov (United States)

    Liu, Tai-Ying; Chen, Yong-Sheng; Hsieh, Jen-Chuen; Chen, Li-Fen

    2015-01-01

    The amygdala has been regarded as a key substrate for emotion processing. However, the engagement of the left and right amygdala during the early perceptual processing of different emotional faces remains unclear. We investigated the temporal profiles of oscillatory gamma activity in the amygdala and effective connectivity of the amygdala with the thalamus and cortical areas during implicit emotion-perceptual tasks using event-related magnetoencephalography (MEG). We found that within 100 ms after stimulus onset the right amygdala habituated to emotional faces rapidly (with duration around 20–30 ms), whereas activity in the left amygdala (with duration around 50–60 ms) sustained longer than that in the right. Our data suggest that the right amygdala could be linked to autonomic arousal generated by facial emotions and the left amygdala might be involved in decoding or evaluating expressive faces in the early perceptual emotion processing. The results of effective connectivity provide evidence that only negative emotional processing engages both cortical and subcortical pathways connected to the right amygdala, representing its evolutional significance (survival). These findings demonstrate the asymmetric engagement of bilateral amygdala in emotional face processing as well as the capability of MEG for assessing thalamo-cortico-limbic circuitry. PMID:25629899

  13. CONSTRAINING GAMMA-RAY BURST EMISSION PHYSICS WITH EXTENSIVE EARLY-TIME, MULTIBAND FOLLOW-UP

    International Nuclear Information System (INIS)

    Cucchiara, A.; Cenko, S. B.; Bloom, J. S.; Morgan, A.; Perley, D. A.; Li, W.; Butler, N. R.; Filippenko, A. V.; Melandri, A.; Kobayashi, S.; Smith, R. J.; Mundell, C. G.; Steele, I. A.; Hora, J. L.; Da Silva, R. L.; Prochaska, J. X.; Worseck, G.; Fumagalli, M.; Milne, P. A.; Cobb, B.

    2011-01-01

    Understanding the origin and diversity of emission processes responsible for gamma-ray bursts (GRBs) remains a pressing challenge. While prompt and contemporaneous panchromatic observations have the potential to test predictions of the internal-external shock model, extensive multiband imaging has been conducted for only a few GRBs. We present rich, early-time, multiband data sets for two Swift events, GRB 110205A and GRB 110213A. The former shows optical emission since the early stages of the prompt phase, followed by the steep rising in flux up to ∼1000 s after the burst (t –α with α = –6.13 ± 0.75). We discuss this feature in the context of the reverse-shock scenario and interpret the following single power-law decay as being forward-shock dominated. Polarization measurements, obtained with the RINGO2 instrument mounted on the Liverpool Telescope, also provide hints on the nature of the emitting ejecta. The latter event, instead, displays a very peculiar optical to near-infrared light curve, with two achromatic peaks. In this case, while the first peak is probably due to the onset of the afterglow, we interpret the second peak to be produced by newly injected material, signifying a late-time activity of the central engine.

  14. CONSTRAINING GAMMA-RAY BURST EMISSION PHYSICS WITH EXTENSIVE EARLY-TIME, MULTIBAND FOLLOW-UP

    Energy Technology Data Exchange (ETDEWEB)

    Cucchiara, A.; Cenko, S. B.; Bloom, J. S.; Morgan, A.; Perley, D. A.; Li, W.; Butler, N. R.; Filippenko, A. V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Melandri, A. [INAF, Osservatorio Astronomicodi Brera, via E. Bianchi 46, I-23807 Merate (Saint Lucia) (Italy); Kobayashi, S.; Smith, R. J.; Mundell, C. G.; Steele, I. A. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead, CH41 1LD (United Kingdom); Hora, J. L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Da Silva, R. L.; Prochaska, J. X.; Worseck, G.; Fumagalli, M. [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Milne, P. A. [Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85719 (United States); Cobb, B., E-mail: acucchia@ucolick.org [Department of Physics, George Washington University, Corcoran 105, 725 21st St, NW, Washington, DC 20052 (United States); and others

    2011-12-20

    Understanding the origin and diversity of emission processes responsible for gamma-ray bursts (GRBs) remains a pressing challenge. While prompt and contemporaneous panchromatic observations have the potential to test predictions of the internal-external shock model, extensive multiband imaging has been conducted for only a few GRBs. We present rich, early-time, multiband data sets for two Swift events, GRB 110205A and GRB 110213A. The former shows optical emission since the early stages of the prompt phase, followed by the steep rising in flux up to {approx}1000 s after the burst (t{sup -{alpha}} with {alpha} = -6.13 {+-} 0.75). We discuss this feature in the context of the reverse-shock scenario and interpret the following single power-law decay as being forward-shock dominated. Polarization measurements, obtained with the RINGO2 instrument mounted on the Liverpool Telescope, also provide hints on the nature of the emitting ejecta. The latter event, instead, displays a very peculiar optical to near-infrared light curve, with two achromatic peaks. In this case, while the first peak is probably due to the onset of the afterglow, we interpret the second peak to be produced by newly injected material, signifying a late-time activity of the central engine.

  15. Gauge theories, time-dependence of the gravitational constant and antigravity in the early universe

    International Nuclear Information System (INIS)

    Linde, A.D.

    1980-01-01

    It is shown that the interaction of the gravitational field with matter leads to a strong modification of the effective gravitational constant in the early universe. In certain cases this leads even to the change of sign of the gravitational constant, i.e. to antigravity in the early universe. (orig.)

  16. GAMMA-RAY BURST REVERSE SHOCK EMISSION IN EARLY RADIO AFTERGLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Resmi, Lekshmi [Indian Institute of Space Science and Technology, Trivandrum (India); Zhang, Bing, E-mail: l.resmi@iist.ac.in [Department of Physics and Astronomy, University of Nevada, Las Vegas (United States)

    2016-07-01

    Reverse shock (RS) emission from gamma-ray bursts is an important tool in investigating the nature of the ejecta from the central engine. If the magnetization of the ejecta is not high enough to suppress the RS, a strong RS emission component, usually peaking in the optical/IR band early on, would provide an important contribution to early afterglow light curve. In the radio band, synchrotron self-absorption may suppress early RS emission and also delay the RS peak time. In this paper, we calculate the self-absorbed RS emission in the radio band under different dynamical conditions. In particular, we stress that the RS radio emission is subject to self-absorption in both RSs and forward shocks (FSs). We calculate the ratio between the RS to FS flux at the RS peak time for different frequencies, which is a measure of the detectability of the RS emission component. We then constrain the range of physical parameters for a detectable RS, in particular the role of magnetization. We notice that unlike optical RS emission which is enhanced by moderate magnetization, moderately magnetized ejecta do not necessarily produce a brighter radio RS due to the self-absorption effect. For typical parameters, the RS emission component would not be detectable below 1 GHz unless the medium density is very low (e.g., n < 10{sup −3} cm{sup −3} for the interstellar medium and A {sub *} < 5 × 10{sup −4} for wind). These predictions can be tested using the afterglow observations from current and upcoming radio facilities such as the Karl G. Jansky Very Large Array, the Low-Frequency Array, the Five Hundred Meter Aperture Spherical Telescope, and the Square Kilometer Array.

  17. Physical and Radiological Characterisation of Measuring Sites Within The Croatian Gamma Dose Rate Early Warning Network

    International Nuclear Information System (INIS)

    Cindro, M.; Stepisnik, M.; Pinezic, D.; Sinka, D.; Skanata, D.

    2016-01-01

    The work described in this paper was done within the EU funded project 'Upgrading the systems for the on- and off-line monitoring of radioactivity in the environment in Croatia in regular and emergency situations'. The existing system of early warning in case of nuclear accident in Croatia (SPUNN), managed by the State Office for Radiological and Nuclear Safety, includes 33 stations for measuring ambient gamma dose rate (GDR). The aim of the project was to determine appropriate correction factors that will allow the results from this network to be used not only for timely warning in case of nuclear accident but also in routine environmental monitoring to determine the background radiation. Additionally, in the case of fresh deposition due to radioactive contamination, the corrected values are better suited to be used as an input for support systems for decision making in the case of emergency (such as RODOS), as well as for international data exchange (EURDEP) or automatic interpolation and mapping of radiological data (INTAMAP). The response of the individual probes to natural or accidental radiation mostly depends on the geometry or topography, surrounding buildings, vegetation (trees) and the type of soil beneath the detector. In the case of measuring the dose rate, objects such as buildings act as a shield against gamma radiation and limit the field of vision of the detector. If we want to have representative values that can be compared with other measuring sites, it is clear that we need to define standard conditions that each location has to meet. This is true not only for the probes within the same network, but can also be applied more broadly, at the international level, since data exchange mechanisms for GDR data already exist across Europe. The response of each probe is not determined only by the physical features, it is also important to understand the radiological characteristics of the site. Radiological characterization was performed through

  18. Diffuse material, background radiation and the early universe

    International Nuclear Information System (INIS)

    Rees, M.J.

    1980-01-01

    Observations that relate to a qualitative picture of how galaxies formed, and what the Universe was really like at still earlier times, are presented. Some lines of evidence on the universe at redshifts out to z approximately equal to 5 are discussed, concentrating on the evidence which suggests that intergalactic medium has evolved in a 'multi phase' fashion. Some aspects of the less recent history of the Universe (i.e z approximately greater than 100) are considered, particularly the microwave background and the spectrum of inhomogeneities. (Auth.)

  19. The baryon asymmetry and CPT invariance in the early universe

    International Nuclear Information System (INIS)

    Barshay, S.

    1981-01-01

    We discuss, and give a definite, simple phenomenological example, of the possibility that the baryon asymmetry is related to a failure of CPT invariance for a brief time interval at the origin of the universe. (orig.)

  20. Detection of early gamma-postirradiation effects in murine spleen by proton NMR relaxation times.

    Science.gov (United States)

    Zebrowska, G; Lewa, C J; Ramee, M P; Husson, F; De Certaines, J D

    2001-01-01

    It was our aim to evaluate the potential of proton relaxation times for the early detection of radiation-induced spleen changes. Female Swiss mice were irradiated with doses ranging from 0.05 Gy to 4 Gy. The body weight, the spleen weight and the spleen water content of single animals were determined. Measurements of longitudinal (T1) and transversal (T2) proton relaxation times of the spleen samples were performed in a 0.47 T spectrometer. Histological examinations of the control and irradiated organs were performed. NMR measurements during the first five days after irradiation showed that total body gamma-irradiation with doses from 1.5 Gy to 4 Gy results in decreasing T1 of the murine spleen. Significant shortening in T2 was observed for the spleen of animals irradiated with a dose of 4 Gy. Histological examinations demonstrated subnormal architecture in slices derived from animals irradiated with 2 Gy and 4 Gy. The fluctuations of the spleen T1 and T2 of irradiated mice are correlated with relative spleen weight and can be used to estimate radiation induced changes in this organ.

  1. Neutron flux and gamma dose measurement in the BNCT irradiation facility at the TRIGA reactor of the University of Pavia

    Science.gov (United States)

    Bortolussi, S.; Protti, N.; Ferrari, M.; Postuma, I.; Fatemi, S.; Prata, M.; Ballarini, F.; Carante, M. P.; Farias, R.; González, S. J.; Marrale, M.; Gallo, S.; Bartolotta, A.; Iacoviello, G.; Nigg, D.; Altieri, S.

    2018-01-01

    University of Pavia is equipped with a TRIGA Mark II research nuclear reactor, operating at a maximum steady state power of 250 kW. It has been used for many years to support Boron Neutron Capture Therapy (BNCT) research. An irradiation facility was constructed inside the thermal column of the reactor to produce a sufficient thermal neutron flux with low epithermal and fast neutron components, and low gamma dose. In this irradiation position, the liver of two patients affected by hepatic metastases from colon carcinoma were irradiated after borated drug administration. The facility is currently used for cell cultures and small animal irradiation. Measurements campaigns have been carried out, aimed at characterizing the neutron spectrum and the gamma dose component. The neutron spectrum has been measured by means of multifoil neutron activation spectrometry and a least squares unfolding algorithm; gamma dose was measured using alanine dosimeters. Results show that in a reference position the thermal neutron flux is (1.20 ± 0.03) ×1010 cm-2 s-1 when the reactor is working at the maximum power of 250 kW, with the epithermal and fast components, respectively, 2 and 3 orders of magnitude lower than the thermal component. The ratio of the gamma dose with respect to the thermal neutron fluence is 1.2 ×10-13 Gy/(n/cm2).

  2. Early effects of external gamma irradiation on iodide metabolism in rat thyroid

    International Nuclear Information System (INIS)

    Niatsetskaya, Z.; Nadolnik, L.

    2006-01-01

    Full text of publication follows: The exposure of the thyroid gland to therapeutic doses of external gamma irradiation is frequently associated with thyroid dysfunction. Although late irradiation effects are well documented, little is still known about the early functional alterations in the thyroid subjected to radiation therapy. The aim of this study was to examine the early effect of single external gamma irradiation on iodide metabolism in the thyroid. The Wistar female rats were irradiated using a 60 Co installation with a constant capacity of 0.64 Gy/min. The doses used were 0.25, 0.5, 1, 2, 5 Gy. The animals were sacrificed after 24 hours following the irradiation. T he thyroid organ culture was cultivated during 24 h and than was irradiated with a single dose of 5 Gy. The thyroid tissue was assayed for thyro-peroxidase activity and concentrations of total, free and protein -binding iodide. It was shown that the 0.25 Gy irradiation depressed thyroid iodide uptake, which was manifested in decreasing total iodide by 25%. The same tendency was observed after the 0.5 Gy irradiation. In the 1, 2, 5 Gy groups, the concentrations of total and free iodide increased by 26 -34% and 50-68%, accordingly. The level of protein-binding iodide in these groups was within the control values. However, protein-binding/total iodide and protein binding/ free iodide ratios decreased by 17 -41%, suggesting inhibition of thyroglobulin iodination. Thyro-peroxidase (T.P.O.) plays a key role in thyroid hormone synthesis by catalyzing both the iodination of thyroglobulin and the coupling some of the iodo-tyrosyl residues. After 24 hours on irradiation, a 31.5-54% dose-dependent inhibition of T.P.O. activity was shown in the 1, 2 and 5 Gy groups. The irradiation of the rat thyroid organ culture with a single dose of 5 Gy also led to significant inhibition of T.P.O. by 56.91% after 2 hours. We compared the enzyme kinetics of thyro-peroxidase from thyroid microsomal fraction control and

  3. Early period of particle accelerator development and nuclear physics experiments at Taihoku Imperial University and Kyoto University (1/2)

    International Nuclear Information System (INIS)

    Takekoshi, Hidekuni

    2007-01-01

    In 1926 Dr. Arakatsu was appointed Professor to Taipei Imperial University in Taiwan which was under the government by Japan in that time, and stared the construction of an electrostatic accelerator in 1930 for nuclear transmutations. He measured the detailed branching ratio of deuteron-lithium reaction following the investigation by Lawrence and Rutherford. In 1936 he was transferred to the physics laboratory of Kyoto University, and constructed a 600kV accelerator of Cockcroft-Walton type. His team studied photo-nuclear reactions using gamma rays produced by the proton-lithium reaction. In 1942 he started on the construction of a cyclotron, which was taken away by US army after the war. He participated in the investigation of the atomic bomb to Hiroshima. (K.Y.)

  4. Predictors of Early Termination in a University Counseling Training Clinic

    Science.gov (United States)

    Lampropoulos, Georgios K.; Schneider, Mercedes K.; Spengler, Paul M.

    2009-01-01

    Despite the existence of counseling dropout research, there are limited predictive data for counseling in training clinics. Potential predictor variables were investigated in this archival study of 380 client files in a university counseling training clinic. Multinomial logistic regression, predictive discriminant analysis, and classification and…

  5. The Early Years of the University of the Witwatersrand Medical ...

    African Journals Online (AJOL)

    1973-01-20

    Jan 20, 1973 ... Witwatersrand Medical School and its Students*. G. R. BEATON, M.B. B.CH. UNIV. .... sion to South African universities, and to travel to. Europe became the .... provement of the residence food at the Queen Victoria. Hospital.

  6. Implications of dark matter free streaming in the early Universe

    NARCIS (Netherlands)

    Diamanti, R.

    2017-01-01

    In this thesis, we link astrophysics and particle physics aspects in order to study the implications of the nature and properties of different types of dark matter candidates on the observable Universe. The main property which connects the different works on which this manuscript is based is

  7. Unilateral irradiation of pigs in a mixed neutrons+gamma field. Early results

    International Nuclear Information System (INIS)

    Lemaitre, Guy; Maas, Jean.

    1982-08-01

    Pigs (16-20kg) were irradiated with 60 Co gamma or in a mixed field (neutron + gamma from the pulsed reactor SILENE). Pigs were unilaterally exposed by the left side. Each experimental group was composed of twelve animals and one control. Within the dose range explored (reference dose is mid-line tissue dose): 4-9.8 Gy of gamma rays only; 4.6 - 5.7 Gy of neutrons and gamma rays, pigs presented the haematopioetic form of the acute radiation sickness. At 5 Gy mixed field was more harmful than gamma rays only. Therefore the numerical value of neutron RBE (lethality 50 p cent within 30 days) is more than one. Experiments will be carried out in order to determine RBE values more accurately. Bone marrow dose will also be determined [fr

  8. James Gregory, the University observatory and the early acquisition of scientific instruments at the University of St Andrews

    Science.gov (United States)

    Rawson, Helen C.

    2015-01-01

    James Gregory, inventor of the reflecting telescope and Fellow of the Royal Society, was the first Regius Professor of Mathematics of the University of St Andrews, 1668–74. He attempted to establish in St Andrews what would, if completed, have been the first purpose-built observatory in the British Isles. He travelled to London in 1673 to purchase instruments for equipping the observatory and improving the teaching and study of natural philosophy and mathematics in the university, seeking the advice of John Flamsteed, later the first Astronomer Royal. This paper considers the observatory initiative and the early acquisition of instruments at the University of St Andrews, with reference to Gregory's correspondence, inventories made ca. 1699–ca. 1718 and extant instruments themselves, some of which predate Gregory's time. It examines the structure and fate of the university observatory, the legacy of Gregory's teaching and endeavours, and the meridian line laid down in 1748 in the University Library.

  9. Statistical mechanics and the description of the early universe I

    DEFF Research Database (Denmark)

    Pessah, Martin Elias; F. Torres, Diego; Vucetich, H.

    2001-01-01

    We analyze how the thermal history of the universe is influenced by the statistical description, assuming a deviation from the usual Bose-Einstein, Fermi-Dirac and Boltzmann-Gibbs distribution functions. These deviations represent the possible appearance of non-extensive effects related with the ......We analyze how the thermal history of the universe is influenced by the statistical description, assuming a deviation from the usual Bose-Einstein, Fermi-Dirac and Boltzmann-Gibbs distribution functions. These deviations represent the possible appearance of non-extensive effects related...... and to place limits to the range of its validity. The corrections obtained will change with temperature, and consequently, the bounds on the possible amount of non-extensivity will also change with time. We generalize results which can be used in other contexts as well, as the Boltzmann equation and the Saha...

  10. Holography for a non-inflationary early universe

    Energy Technology Data Exchange (ETDEWEB)

    Hinterbichler, Kurt [Perimeter Institute for Theoretical Physics,31 Caroline St. N, Waterloo, Ontario, N2L 2Y5 (Canada); Stokes, James; Trodden, Mark [Center for Particle Cosmology, Department of Physics and Astronomy,University of Pennsylvania,209 South 33rd Street, Philadelphia, PA 19104 (United States)

    2015-01-19

    We construct a gravitational dual of the pseudo-conformal universe, a proposed alternative to inflation in which a conformal field theory in nearly flat space develops a time dependent vacuum expectation value. Constructing this dual amounts to finding five-dimensional domain-wall spacetimes with anti-de Sitter asymptotics, for which the wall has the symmetries of four-dimensional de Sitter space. This holographically realizes the characteristic symmetry breaking pattern so(2,4)→so(1,4) of the pseudo-conformal universe. We present an explicit example with a massless scalar field, using holographic renormalization to obtain general expressions for the renormalized scalar and stress-tensor one-point functions. We discuss the relationship between these solutions and those of four-dimensional holographic defect conformal field theories which break so(2,4)→so(2,3).

  11. Holography for a non-inflationary early universe

    International Nuclear Information System (INIS)

    Hinterbichler, Kurt; Stokes, James; Trodden, Mark

    2015-01-01

    We construct a gravitational dual of the pseudo-conformal universe, a proposed alternative to inflation in which a conformal field theory in nearly flat space develops a time dependent vacuum expectation value. Constructing this dual amounts to finding five-dimensional domain-wall spacetimes with anti-de Sitter asymptotics, for which the wall has the symmetries of four-dimensional de Sitter space. This holographically realizes the characteristic symmetry breaking pattern so(2,4)→so(1,4) of the pseudo-conformal universe. We present an explicit example with a massless scalar field, using holographic renormalization to obtain general expressions for the renormalized scalar and stress-tensor one-point functions. We discuss the relationship between these solutions and those of four-dimensional holographic defect conformal field theories which break so(2,4)→so(2,3).

  12. Calibration of A Prompt Gamma Neutron Activation Analysis (PGNAA) Facility: Experience at the Oregon State University TRIGA Reactor

    International Nuclear Information System (INIS)

    Norlida Yussup

    2011-01-01

    A prompt gamma neutron activation analysis (PGNAA) facility at Oregon State University (OSU) TRIGA reactor has been built in year 2008 and been operated since then. PGNAA is a technique used to determine the presence and quantity of trace elements such as boron, hydrogen and carbon which are more difficult to detect with other neutron analysis method. A calibration is essential to ensure the system works as required and the output is valid and reliable. The calibration was carried out by using Standard Reference Material (SRM). Besides, background data was also acquired for comparisons and analysis. The results are analyzed and discussed in this paper. (author)

  13. Evolution of the early universe and big-bang nucleosynthesis

    International Nuclear Information System (INIS)

    Kajino, T.

    1995-01-01

    Cosmological phase transition can create strongly inhomogeneous baryon density distribution. Inhomogeneous big-bang model for primordial nucleosynthesis allows higher universal mass density parameter of baryons than the standard model does, which is marginally consistent with recent astronomical suggestion that some kind of dark matter is made of baryons. Enhanced heavy-element abundances in halo dwarfs is shown to be an observational signature for the inhomogeneous big-bang model. The studies of radioactive nuclear reactions help predict the theoretical abundances of these elements more precisely. (author). 53 refs., 8 figs

  14. Social Strategies during University Studies Predict Early Career Work Burnout and Engagement: 18-Year Longitudinal Study

    Science.gov (United States)

    Salmela-Aro, Katariina; Tolvanen, Asko; Nurmi, Jari-Erik

    2011-01-01

    This longitudinal study spanning 18 years examined the role of social strategies in early career adaptation. The aim was to find out whether individuals' social strategies measured during their university studies had an impact on work burnout and work engagement measured 10-18 years later. A sample of 292 university students completed the SAQ…

  15. Universal Design for Learning: Cognitive Theory into Practice for Facilitating Comprehension in Early Literacy

    Science.gov (United States)

    Brand, Susan Trostle; Dalton, Elizabeth M.

    2012-01-01

    Addressing the unique needs of children of all ages and abilities, Universal Design for Learning (UDL) is gaining momentum in schools and preschools around the nation and the globe. This article explores Universal Design for Learning and its promising applications to a variety of reading and language arts experiences in the Early Childhood…

  16. Gamma-ray bursts from stellar remnants - Probing the universe at high redshift

    NARCIS (Netherlands)

    Wijers, R.A.M.J.; Bloom, J.S.; Bagla, J.S.; Natarajan, P.

    1998-01-01

    A gamma-ray burst (GRB) releases an amount of energy similar to that of a supernova explosion, which combined with its rapid variability suggests an origin related to neutron stars or black holes. Since these compact stellar remnants form from the most massive stars not long after their birth, GRBs

  17. STAR FORMATION IN THE EARLY UNIVERSE: BEYOND THE TIP OF THE ICEBERG

    Energy Technology Data Exchange (ETDEWEB)

    Tanvir, N. R.; Wiersema, K.; O' Brien, P. T.; Starling, R. L. C. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Levan, A. J.; Stanway, E. R. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Fruchter, A. S.; Misra, K.; Graham, J. F. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Fynbo, J. P. U.; Hjorth, J.; Watson, D. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Bremer, M. N. [HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Rhoads, J. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Jakobsson, P. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik (Iceland); Bersier, D. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool (United Kingdom); Natarajan, P. [Department of Astronomy, Yale University, New Haven, CT 06511-208101 (United States); Greiner, J. [Max-Planck-Institut fuer extraterrestrische Physik, Garching bei Muenchen (Germany); Castro-Tirado, A. J. [Instituto de Astrofsica de Andalucia (IAA-CSIC), Glorieta de la Astronomia s/n, 18.008 Granada (Spain); Wijers, R. A. M. J., E-mail: nrt3@star.le.ac.uk [Astronomical Institute ' Anton Pannekoek' , P.O. Box 94248, 1090 SJ Amsterdam (Netherlands); and others

    2012-07-20

    We present late-time Hubble Space Telescope (HST) imaging of the fields of six Swift gamma-ray bursts (GRBs) lying at 5.0 {approx}< z {approx}< 9.5. Our data include very deep observations of the field of the most distant spectroscopically confirmed burst, GRB 090423, at z = 8.2. Using the precise positions afforded by their afterglows, we can place stringent limits on the luminosities of their host galaxies. In one case, that of GRB 060522 at z 5.11, there is a marginal excess of flux close to the GRB position which may be a detection of a host at a magnitude J{sub AB} Almost-Equal-To 28.5. None of the others are significantly detected, meaning that all the hosts lie below L* at their respective redshifts, with star formation rates (SFRs) {approx}< 4 M{sub Sun} yr{sup -1} in all cases. Indeed, stacking the five fields with WFC3-IR data, we conclude a mean SFR <0.17 M{sub Sun} yr{sup -1} per galaxy. These results support the proposition that the bulk of star formation, and hence integrated UV luminosity, at high redshifts arises in galaxies below the detection limits of deep-field observations. Making the reasonable assumption that GRB rate is proportional to UV luminosity at early times allows us to compare our limits with expectations based on galaxy luminosity functions (LFs) derived from the Hubble Ultra-Deep Field and other deep fields. We infer that an LF, which is evolving rapidly toward steeper faint-end slope ({alpha}) and decreasing characteristic luminosity (L*), as suggested by some other studies, is consistent with our observations, whereas a non-evolving LF shape is ruled out at {approx}> 90% confidence. Although it is not yet possible to make stronger statements, in the future, with larger samples and a fuller understanding of the conditions required for GRB production, studies like this hold great potential for probing the nature of star formation, the shape of the galaxy LF, and the supply of ionizing photons in the early universe.

  18. Encouraging entrepreneurship in university labs: Research activities, research outputs, and early doctorate careers

    OpenAIRE

    Roach, Michael

    2017-01-01

    This paper investigates how the encouragement of entrepreneurship within university research labs relates with research activities, research outputs, and early doctorate careers. Utilizing a panel survey of 6,840 science & engineering doctoral students at 39 R1 research universities, this study shows that entrepreneurship is widely encouraged across university research labs, ranging from 54% in biomedical engineering to 18% in particle physics, while only a small share of labs openly discoura...

  19. The induced expression of heat shock proteins as a part of the early cellular response to gamma radiation

    International Nuclear Information System (INIS)

    Stankova, K.; Ivanova, K.; Georgieva, R.; Rupova, I.; Boteva, R.

    2008-01-01

    A variety of stressful stimuli including gamma radiation can induce increase in the synthesis of heat shock proteins (Hsp). This family of molecular chaperones includes members with molecular masses ranging from 10 to 150 kDa and has been identified in all organisms from bacteria to humans. Hsp70 chaperones are very important. The present study aimed to characterize the radiation-induced changes in Hsp70 synthesis in human lymphocytes as a part of the early cellular response to gamma irradiation. The expression of Hsp70 was determined with Western blot and the radiation-induced apoptotic changes were registered by staining with fluorescent dyes. Part of the experiments were performed in the presence of the organic solvent DMSO. At low concentrations this reagent shows antioxidant activity and can reduce the level of the radiation-induced oxidant stress which determines the predominant biological effects of the ionizing radiation. Irradiation with 0.5 to 8 Gy caused statistically significant increase in the synthesis of Hsp70 which was strongest after irradiation with 4 Gy. In the range 0.5-2 Gy the enhancement of the radiation-induced synthesis of Hsp70 reached 60%. Our experimental results characterize changes in the Hsp70 synthesis after gamma irradiation as a part of the early cellular stress response in lymphocytes. (authors)

  20. The Cosmic Microwave Background Radiation-A Unique Window on the Early Universe

    Science.gov (United States)

    Hinshaw, Gary

    2010-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics of the early universe. Within the framework of inflationary dark matter models, observations of the anisotropy on sub-degree angular scales reveals the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of 11 00. Data from the first seven years of operation of the Wilkinson Microwave Anisotropy Probe (WMAP) satellite provide detailed full-sky maps of the cosmic microwave background temperature and polarization anisotropy. Together, the data provide a wealth of cosmological information, including the age of the universe, the epoch when the first stars formed, and the overall composition of baryonic matter, dark matter, and dark energy. The results also provide constraints on the period of inflationary expansion in the very first moments of time. WMAP, part of NASA's Explorers program, was launched on June 30, 2001. The WMAP satellite was produced in a partnership between the Goddard Space Flight Center and Princeton University. The WMAP team also includes researchers at the Johns Hopkins University; the Canadian Institute of Theoretical Astrophysics; University of Texas; Oxford University; University of Chicago; Brown University; University of British Columbia; and University of California, Los Angeles.

  1. Constraining resonant photon-axion conversions in the Early Universe

    International Nuclear Information System (INIS)

    Mirizzi, Alessandro; Redondo, Javier; Sigl, Guenter

    2009-05-01

    The presence of a primordial magnetic field would have induced resonant conversions between photons and axion-like particles (ALPs) during the thermal history of the Universe. These conversions would have distorted the blackbody spectrum of the cosmic microwave background (CMB). In this context, we derive bounds on the photon-ALP resonant conversions using the high precision CMB spectral data collected by the FIRAS instrument on board of the Cosmic Background Explorer. We obtain upper limits on the product of the photon-ALP coupling constant g times the magnetic field strength B down to gB -13 GeV -1 nG for ALP masses below the eV scale. (orig.)

  2. High-Redshift galaxies light from the early universe

    CERN Document Server

    Appenzeller, Immo

    2008-01-01

    This book provides a comprehensive account of the scientific results on high-redshift galaxies accumulated during the past ten years. Apart from summarizing and critically discussing the wealth of observational data, the observational methods which made it possible to study these very distant and extremely faint objects are described in detail. Moreover, the technical feasibilities and physical limitations for existing and for future ground-based and space-based telescopes are discussed. Thus, apart from summarizing the knowledge accumulated so far, the book is designed as a tool for planning future observational and instrumental programs and projects. In view of the potential importance of the observational results of the high-redshift universe for basic physics the book is written for astronomers as well as for physicists without prior astronomical knowledge. For this purpose it contains introductory chapters describing the basic concepts and notations used in modern astronomy and a brief overview of the pr...

  3. The art and science of prognostication in early university medicine.

    Science.gov (United States)

    Demaitre, Luke

    2003-01-01

    Prognosis occupied a more prominent place in the medieval curriculum than it does at the modern university. Scholastic discussions were rooted in the Hippocratic Aphorisms and shaped by Galen's treatises On Crisis and On Critical Days. Medical prediction, as an art dependent on personal skills such as memory and conjecture, was taught with the aid of the liberal arts of rhetoric and logic. Scientific predictability was sought in branches of mathematics, moving from periodicity and numerology to astronomy. The search for certitude contributed to the cultivation of astrology; even at its peak, however, astrological medicine did not dominate the teaching on prognostication. The ultimate concern, which awaits further discussion, was not even with forecasting as such, but with the physician and, indeed, the patient.

  4. Constraining resonant photon-axion conversions in the Early Universe

    Energy Technology Data Exchange (ETDEWEB)

    Mirizzi, Alessandro [Max-Planck-Inst. fuer Physik (Werner-Heisenberg-Inst.), Muenchen (Germany); Redondo, Javier [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Sigl, Guenter [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik

    2009-05-15

    The presence of a primordial magnetic field would have induced resonant conversions between photons and axion-like particles (ALPs) during the thermal history of the Universe. These conversions would have distorted the blackbody spectrum of the cosmic microwave background (CMB). In this context, we derive bounds on the photon-ALP resonant conversions using the high precision CMB spectral data collected by the FIRAS instrument on board of the Cosmic Background Explorer. We obtain upper limits on the product of the photon-ALP coupling constant g times the magnetic field strength B down to gB

  5. Anisotropic, nonsingular early universe model leading to a realistic cosmology

    International Nuclear Information System (INIS)

    Dechant, Pierre-Philippe; Lasenby, Anthony N.; Hobson, Michael P.

    2009-01-01

    We present a novel cosmological model in which scalar field matter in a biaxial Bianchi IX geometry leads to a nonsingular 'pancaking' solution: the hypersurface volume goes to zero instantaneously at the 'big bang', but all physical quantities, such as curvature invariants and the matter energy density remain finite, and continue smoothly through the big bang. We demonstrate that there exist geodesics extending through the big bang, but that there are also incomplete geodesics that spiral infinitely around a topologically closed spatial dimension at the big bang, rendering it, at worst, a quasiregular singularity. The model is thus reminiscent of the Taub-NUT vacuum solution in that it has biaxial Bianchi IX geometry and its evolution exhibits a dimensionality reduction at a quasiregular singularity; the two models are, however, rather different, as we will show in a future work. Here we concentrate on the cosmological implications of our model and show how the scalar field drives both isotropization and inflation, thus raising the question of whether structure on the largest scales was laid down at a time when the universe was still oblate (as also suggested by [T. S. Pereira, C. Pitrou, and J.-P. Uzan, J. Cosmol. Astropart. Phys. 9 (2007) 6.][C. Pitrou, T. S. Pereira, and J.-P. Uzan, J. Cosmol. Astropart. Phys. 4 (2008) 4.][A. Guemruekcueoglu, C. Contaldi, and M. Peloso, J. Cosmol. Astropart. Phys. 11 (2007) 005.]). We also discuss the stability of our model to small perturbations around biaxiality and draw an analogy with cosmological perturbations. We conclude by presenting a separate, bouncing solution, which generalizes the known bouncing solution in closed FRW universes.

  6. The quark gluon plasma equation of state and the expansion of the early Universe

    International Nuclear Information System (INIS)

    Sanches, S.M.; Navarra, F.S.; Fogaça, D.A.

    2015-01-01

    Our knowledge of the equation of state of the quark gluon plasma has been continuously growing due to the experimental results from heavy ion collisions, due to recent astrophysical measurements and also due to the advances in lattice QCD calculations. The new findings about this state may have consequences on the time evolution of the early Universe, which can be estimated by solving the Friedmann equations. The solutions of these equations give the time evolution of the energy density and also of the temperature in the beginning of the Universe. In this work we compute the time evolution of the QGP in the early Universe, comparing several equations of state, some of them based on the MIT bag model (and on its variants) and some of them based on lattice QCD calculations. Among other things, we investigate the effects of a finite baryon chemical potential in the evolution of the early Universe

  7. Jagiellonian University Selected Results on the CKM Angle $\\gamma $ Measurement at the LHCb

    CERN Document Server

    Krupa, Wojciech

    2017-01-01

    The LHCb is a single arm forward spectrometer designed to study heavy-flavour physics at the LHC. Its very precise tracking and excellent particle identification play currently a major role in providing the world-best measurements of the Unitary Triangle parameters. In this paper, selected results of the Cabibbo–Kobayashi–Maskawa (CKM) angle $\\gamma$ measurements, with special attention for $B \\rightarrow DK$ decays family, obtained at the LHCb, are presented.

  8. Relativistic inverse Compton scattering of photons from the early universe.

    Science.gov (United States)

    Malu, Siddharth; Datta, Abhirup; Colafrancesco, Sergio; Marchegiani, Paolo; Subrahmanyan, Ravi; Narasimha, D; Wieringa, Mark H

    2017-12-05

    Electrons at relativistic speeds, diffusing in magnetic fields, cause copious emission at radio frequencies in both clusters of galaxies and radio galaxies through non-thermal radiation emission called synchrotron. However, the total power radiated through this mechanism is ill constrained, as the lower limit of the electron energy distribution, or low-energy cutoffs, for radio emission in galaxy clusters and radio galaxies, have not yet been determined. This lower limit, parametrized by the lower limit of the electron momentum - p min - is critical for estimating the total energetics of non-thermal electrons produced by cluster mergers or injected by radio galaxy jets, which impacts the formation of large-scale structure in the universe, as well as the evolution of local structures inside galaxy clusters. The total pressure due to the relativistic, non-thermal population of electrons can be measured using the Sunyaev-Zel'dovich Effect, and is critically dependent on p min , making the measurement of this non-thermal pressure a promising technique to estimate the electron low-energy cutoff. We present here the first unambiguous detection of this Sunyaev-Zel'dovich Effect for a non-thermal population of electrons in a radio galaxy jet/lobe, located at a significant distance away from the center of the Bullet cluster of galaxies.

  9. A massive, dead disk galaxy in the early Universe.

    Science.gov (United States)

    Toft, Sune; Zabl, Johannes; Richard, Johan; Gallazzi, Anna; Zibetti, Stefano; Prescott, Moire; Grillo, Claudio; Man, Allison W S; Lee, Nicholas Y; Gómez-Guijarro, Carlos; Stockmann, Mikkel; Magdis, Georgios; Steinhardt, Charles L

    2017-06-21

    At redshift z = 2, when the Universe was just three billion years old, half of the most massive galaxies were extremely compact and had already exhausted their fuel for star formation. It is believed that they were formed in intense nuclear starbursts and that they ultimately grew into the most massive local elliptical galaxies seen today, through mergers with minor companions, but validating this picture requires higher-resolution observations of their centres than is currently possible. Magnification from gravitational lensing offers an opportunity to resolve the inner regions of galaxies. Here we report an analysis of the stellar populations and kinematics of a lensed z = 2.1478 compact galaxy, which-surprisingly-turns out to be a fast-spinning, rotationally supported disk galaxy. Its stars must have formed in a disk, rather than in a merger-driven nuclear starburst. The galaxy was probably fed by streams of cold gas, which were able to penetrate the hot halo gas until they were cut off by shock heating from the dark matter halo. This result confirms previous indirect indications that the first galaxies to cease star formation must have gone through major changes not just in their structure, but also in their kinematics, to evolve into present-day elliptical galaxies.

  10. Stability of extra dimensions in the inflating early universe

    International Nuclear Information System (INIS)

    Wieck, Clemens

    2015-08-01

    Cosmic inflation is an attractive paradigm to explain the initial conditions of the universe. It can be conveniently described by the dynamics of a single scalar field within N=1 supergravity. Due to the high energy scale during the inflationary epoch, which is favored by recent observations of the cosmic microwave background radiation, and the flatness of the inflaton potential it is necessary to consider inflation in the context of a UV-complete theory like string theory. To this end, we study the effects of moduli stabilization on inflation models in supergravity, focussing on Kahler moduli in type IIB string theory which govern the size of extra dimensions. For generic models of F-term inflation we calculate back-reaction terms by integrating out the moduli at a high energy scale. When the moduli are stabilized supersymmetrically, all effects decouple in the limit of very heavy moduli. The corrections, however, may be sizeable for realistic moduli masses above the Hubble scale and affect the predicted observables of many models like chaotic inflation and hybrid inflation. If, on the other hand, moduli stabilization entails spontaneous supersymmetry breaking, there are non-decoupling effects like soft mass terms for the inflaton. By the example of chaotic inflation we show that a careful choice of parameters and initial conditions is necessary to reconcile large-field inflation with popular moduli stabilization schemes like KKLT stabilization or the Large Volume Scenario. Furthermore, we study the interplay of moduli stabilization and D-term inflation. If inflation is driven by a constant Fayet-Iliopoulos term, the back-reaction decouples but the gravitino mass in the vacuum is surprisingly constrained. For a field-dependent Fayet-Iliopoulos term associated with an anomalous U(1) symmetry we discuss a number of obstructions to realizing inflation. Moreover, we propose a way to evade them using a new mechanism for supersymmetric moduli stabilization with world

  11. Early optical emission from the gamma-ray burst of 4 October 2002.

    Science.gov (United States)

    Fox, D W; Yost, S; Kulkarni, S R; Torii, K; Kato, T; Yamaoka, H; Sako, M; Harrison, F A; Sari, R; Price, P A; Berger, E; Soderberg, A M; Djorgovski, S G; Barth, A J; Pravdo, S H; Frail, D A; Gal-Yam, A; Lipkin, Y; Mauch, T; Harrison, C; Buttery, H

    2003-03-20

    Observations of the long-lived emission--or 'afterglow'--of long-duration gamma-ray bursts place them at cosmological distances, but the origin of these energetic explosions remains a mystery. Observations of optical emission contemporaneous with the burst of gamma-rays should provide insight into the details of the explosion, as well as into the structure of the surrounding environment. One bright optical flash was detected during a burst, but other efforts have produced negative results. Here we report the discovery of the optical counterpart of GRB021004 only 193 seconds after the event. The initial decline is unexpectedly slow and requires varying energy content in the gamma-ray burst blastwave over the course of the first hour. Further analysis of the X-ray and optical afterglow suggests additional energy variations over the first few days.

  12. Decrease in early right alpha band phase synchronization and late gamma band oscillations in processing syntax in music.

    Science.gov (United States)

    Ruiz, María Herrojo; Koelsch, Stefan; Bhattacharya, Joydeep

    2009-04-01

    The present study investigated the neural correlates associated with the processing of music-syntactical irregularities as compared with regular syntactic structures in music. Previous studies reported an early ( approximately 200 ms) right anterior negative component (ERAN) by traditional event-related-potential analysis during music-syntactical irregularities, yet little is known about the underlying oscillatory and synchronization properties of brain responses which are supposed to play a crucial role in general cognition including music perception. First we showed that the ERAN was primarily represented by low frequency (music-syntactical irregularities as compared with music-syntactical regularities, were associated with (i) an early decrease in the alpha band (9-10 Hz) phase synchronization between right fronto-central and left temporal brain regions, and (ii) a late ( approximately 500 ms) decrease in gamma band (38-50 Hz) oscillations over fronto-central brain regions. These results indicate a weaker degree of long-range integration when the musical expectancy is violated. In summary, our results reveal neural mechanisms of music-syntactic processing that operate at different levels of cortical integration, ranging from early decrease in long-range alpha phase synchronization to late local gamma oscillations. 2008 Wiley-Liss, Inc.

  13. External gamma irradiation-induced effects in early-life stages of zebrafish, Danio rerio

    International Nuclear Information System (INIS)

    Gagnaire, B.; Cavalié, I.; Pereira, S.; Floriani, M.; Dubourg, N.; Camilleri, V.; Adam-Guillermin, C.

    2015-01-01

    Highlights: • The present study aimed to evaluate the effects of gamma rays on zebrafish larvae. • Different techniques were used: gene expression, biochemistry, microscopy and macroscopical observations. • The results showed that gamma irradiation can alter embryo-larval development at several levels of organization. - Abstract: In the general context of validation of tools useful for the characterization of ecological risk linked to ionizing radiation, the effects of an external gamma irradiation were studied in zebrafish larvae irradiated for 96 h with two dose rates: 0.8 mGy/d, which is close to the level recommended to protect ecosystems from adverse effects of ionizing radiation (0.24 mGy/d) and a higher dose rate of 570 mGy/d. Several endpoints were investigated, such as mortality, hatching, and some parameters of embryo-larval development, immunotoxicity, apoptosis, genotoxicity, neurotoxicity and histological alterations. Results showed that an exposure to gamma rays induced an acceleration of hatching for both doses and a decrease of yolk bag diameter for the highest dose, which could indicate an increase of global metabolism. AChE activity decreased with the low dose rate of gamma irradiation and alterations were also shown in muscles of irradiated larvae. These results suggest that gamma irradiation can induce damages on larval neurotransmission, which could have repercussions on locomotion. DNA damages, basal ROS production and apoptosis were also induced by irradiation, while ROS stimulation index and EROD biotransformation activity were decreased and gene expression of acetylcholinesterase, choline acetyltransferase, cytochrome p450 and myeloperoxidase increased. These results showed that ionizing radiation induced an oxidative stress conducting to DNA damages. This study characterized further the modes of action of ionizing radiation in fish.

  14. External gamma irradiation-induced effects in early-life stages of zebrafish, Danio rerio

    Energy Technology Data Exchange (ETDEWEB)

    Gagnaire, B., E-mail: beatrice.gagnaire@irsn.fr [Institut de Radioprotection et de Sureté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Saint-Paul-lez-Durance 13115 (France); Cavalié, I. [Institut de Radioprotection et de Sureté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Saint-Paul-lez-Durance 13115 (France); Pereira, S. [Neolys Diagnostics, Lyon 69373 (France); Floriani, M.; Dubourg, N.; Camilleri, V.; Adam-Guillermin, C. [Institut de Radioprotection et de Sureté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Saint-Paul-lez-Durance 13115 (France)

    2015-12-15

    Highlights: • The present study aimed to evaluate the effects of gamma rays on zebrafish larvae. • Different techniques were used: gene expression, biochemistry, microscopy and macroscopical observations. • The results showed that gamma irradiation can alter embryo-larval development at several levels of organization. - Abstract: In the general context of validation of tools useful for the characterization of ecological risk linked to ionizing radiation, the effects of an external gamma irradiation were studied in zebrafish larvae irradiated for 96 h with two dose rates: 0.8 mGy/d, which is close to the level recommended to protect ecosystems from adverse effects of ionizing radiation (0.24 mGy/d) and a higher dose rate of 570 mGy/d. Several endpoints were investigated, such as mortality, hatching, and some parameters of embryo-larval development, immunotoxicity, apoptosis, genotoxicity, neurotoxicity and histological alterations. Results showed that an exposure to gamma rays induced an acceleration of hatching for both doses and a decrease of yolk bag diameter for the highest dose, which could indicate an increase of global metabolism. AChE activity decreased with the low dose rate of gamma irradiation and alterations were also shown in muscles of irradiated larvae. These results suggest that gamma irradiation can induce damages on larval neurotransmission, which could have repercussions on locomotion. DNA damages, basal ROS production and apoptosis were also induced by irradiation, while ROS stimulation index and EROD biotransformation activity were decreased and gene expression of acetylcholinesterase, choline acetyltransferase, cytochrome p450 and myeloperoxidase increased. These results showed that ionizing radiation induced an oxidative stress conducting to DNA damages. This study characterized further the modes of action of ionizing radiation in fish.

  15. Early universe cosmology. In supersymmetric extensions of the standard model

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, Jochen Peter

    2012-03-19

    In this thesis we investigate possible connections between cosmological inflation and leptogenesis on the one side and particle physics on the other side. We work in supersymmetric extensions of the Standard Model. A key role is played by the right-handed sneutrino, the superpartner of the right-handed neutrino involved in the type I seesaw mechanism. We study a combined model of inflation and non-thermal leptogenesis that is a simple extension of the Minimal Supersymmetric Standard Model (MSSM) with conserved R-parity, where we add three right-handed neutrino super fields. The inflaton direction is given by the imaginary components of the corresponding scalar component fields, which are protected from the supergravity (SUGRA) {eta}-problem by a shift symmetry in the Kaehler potential. We discuss the model first in a globally supersymmetric (SUSY) and then in a supergravity context and compute the inflationary predictions of the model. We also study reheating and non-thermal leptogenesis in this model. A numerical simulation shows that shortly after the waterfall phase transition that ends inflation, the universe is dominated by right-handed sneutrinos and their out-of-equilibrium decay can produce the desired matter-antimatter asymmetry. Using a simplified time-averaged description, we derive analytical expressions for the model predictions. Combining the results from inflation and leptogenesis allows us to constrain the allowed parameter space from two different directions, with implications for low energy neutrino physics. As a second thread of investigation, we discuss a generalisation of the inflationary model discussed above to include gauge non-singlet fields as inflatons. This is motivated by the fact that in left-right symmetric, supersymmetric Grand Unified Theories (SUSY GUTs), like SUSY Pati-Salam unification or SUSY SO(10) GUTs, the righthanded (s)neutrino is an indispensable ingredient and does not have to be put in by hand as in the MSSM. We discuss

  16. Early universe cosmology. In supersymmetric extensions of the standard model

    International Nuclear Information System (INIS)

    Baumann, Jochen Peter

    2012-01-01

    In this thesis we investigate possible connections between cosmological inflation and leptogenesis on the one side and particle physics on the other side. We work in supersymmetric extensions of the Standard Model. A key role is played by the right-handed sneutrino, the superpartner of the right-handed neutrino involved in the type I seesaw mechanism. We study a combined model of inflation and non-thermal leptogenesis that is a simple extension of the Minimal Supersymmetric Standard Model (MSSM) with conserved R-parity, where we add three right-handed neutrino super fields. The inflaton direction is given by the imaginary components of the corresponding scalar component fields, which are protected from the supergravity (SUGRA) η-problem by a shift symmetry in the Kaehler potential. We discuss the model first in a globally supersymmetric (SUSY) and then in a supergravity context and compute the inflationary predictions of the model. We also study reheating and non-thermal leptogenesis in this model. A numerical simulation shows that shortly after the waterfall phase transition that ends inflation, the universe is dominated by right-handed sneutrinos and their out-of-equilibrium decay can produce the desired matter-antimatter asymmetry. Using a simplified time-averaged description, we derive analytical expressions for the model predictions. Combining the results from inflation and leptogenesis allows us to constrain the allowed parameter space from two different directions, with implications for low energy neutrino physics. As a second thread of investigation, we discuss a generalisation of the inflationary model discussed above to include gauge non-singlet fields as inflatons. This is motivated by the fact that in left-right symmetric, supersymmetric Grand Unified Theories (SUSY GUTs), like SUSY Pati-Salam unification or SUSY SO(10) GUTs, the righthanded (s)neutrino is an indispensable ingredient and does not have to be put in by hand as in the MSSM. We discuss the

  17. Early warning for VHE gamma-ray flares with the ARGO-YBJ detector

    Energy Technology Data Exchange (ETDEWEB)

    Bartoli, B. [Dipartimento di Fisica dell' Universita di Napoli ' Federico II' , Complesso Universitario di Monte Sant' Angelo, via Cinthia, 80126 Napoli (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Complesso Universitario di Monte Sant' Angelo, via Cinthia, 80126 Napoli (Italy); Bernardini, P. [Dipartimento di Fisica dell' Universita del Salento, via per Arnesano, 73100 Lecce (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Lecce, via per Arnesano, 73100 Lecce (Italy); Bi, X.J. [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918, 100049 Beijing (China); Bleve, C. [Dipartimento di Fisica dell' Universita del Salento, via per Arnesano, 73100 Lecce (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Lecce, via per Arnesano, 73100 Lecce (Italy); Bolognino, I. [Dipartimento di Fisica Nucleare e Teorica dell' Universita di Pavia, via Bassi 6, 27100 Pavia (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, via Bassi 6, 27100 Pavia (Italy); Branchini, P.; Budano, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, via della Vasca Navale 84, 00146 Roma (Italy); Calabrese Melcarne, A.K. [Istituto Nazionale di Fisica Nucleare - CNAF, Viale Berti-Pichat 6/2, 40127 Bologna (Italy); Camarri, P. [Dipartimento di Fisica dell' Universita di Roma ' Tor Vergata' , via della Ricerca Scientifica 1, 00133 Roma (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy); Cao, Z. [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918, 100049 Beijing (China); and others

    2011-12-11

    Detecting and monitoring emissions from flaring gamma-ray sources in the very-high-energy (VHE, > 100 GeV) band is a very important topic in gamma-ray astronomy. The ARGO-YBJ detector is characterized by a high duty cycle and a wide field of view. Therefore, it is particularly capable of detecting flares from extragalactic objects. Based on fast reconstruction and analysis, real-time monitoring of 33 selected VHE extragalactic sources is implemented. Flares exceeding a specific threshold are reported timely, hence enabling the follow-up observation of these objects using more sensitive detectors, such as Cherenkov telescopes.

  18. Ultra-fast flash observatory for detecting the early photons from gamma-ray bursts

    DEFF Research Database (Denmark)

    Lim, H.; Jeong, S.; Ahn, K.-B.

    ) for the fast measurement of the UV-optical photons from GRBs, and a gamma-ray monitor for energy measurement. The triggering is done by the UFFO burst Alert & Trigger telescope (UBAT) using the hard X-ray from GRBs and the UV/optical Trigger Assistant Telescope (UTAT) using the UV/optical photons from GRBs...

  19. Ultra-Fast Flash Observatory for the observation of early photons from gamma-ray bursts

    DEFF Research Database (Denmark)

    Park, I H; Brandt, Søren; Budtz-Jørgensen, Carl

    2013-01-01

    One of the least documented and understood aspects of gamma-ray bursts (GRBs) is the rise phase of the optical light curve. The Ultra-Fast Flash Observatory (UFFO) is an effort to address this question through extraordinary opportunities presented by a series of space missions including a small s...

  20. Ultra-Fast Flash Observatory (uffo) for Observation of Early Photons from Gamma Ray Bursts

    DEFF Research Database (Denmark)

    Park, I. H.; Ahmad, S.; Barrillon, P.

    2013-01-01

    One of the least documented and understood aspects of gamma-ray bursts (GRB) is the rise phase of the optical light curve. The Ultra-Fast Flash Observatory (UFFO) is an effort to address this question through extraordinary opportunities presented by a series of space missions including a small sp...

  1. Two Early Gamma-ray Bursts Optical Afterglow Detections with TAOS Telescopes--GRB 071010B and GRB 071112C

    International Nuclear Information System (INIS)

    Huang, K. Y.; Wang, S. Y.; Urata, Y.

    2009-01-01

    We present on two early detections of GRB afterglows with the Taiwanese-American Occltation Sruvey (TAOS) telescopes. The robotic TAOS system has been devised so that the routine Kuiper Belt Object (KBO) survey is interrupted when a GRB alert is triggered. Our first detection, GRB 071010B was detected by TAOS 62 s after the burst and showed a weak early brightening during the observations. No significant correction with the prompt gamma-ray emission indicated that our optical emission detected is afterglow emission. The second detection of TAOS, GRB 071112C was detected 96 s after the burst, also showed a possible initial raising then followed a steep decay in the R-band light curve.

  2. EARLY AFTERGLOWS OF GAMMA-RAY BURSTS IN A STRATIFIED MEDIUM WITH A POWER-LAW DENSITY DISTRIBUTION

    International Nuclear Information System (INIS)

    Yi, Shuang-Xi; Dai, Zi-Gao; Wu, Xue-Feng

    2013-01-01

    A long-duration gamma-ray burst (GRB) has been widely thought to arise from the collapse of a massive star, and it has been suggested that its ambient medium is a homogenous interstellar medium (ISM) or a stellar wind. There are two shocks when an ultra-relativistic fireball that has been ejected during the prompt gamma-ray emission phase sweeps up the circumburst medium: a reverse shock that propagates into the fireball, and a forward shock that propagates into the ambient medium. In this paper, we investigate the temporal evolution of the dynamics and emission of these two shocks in an environment with a general density distribution of n∝R –k (where R is the radius) by considering thick-shell and thin-shell cases. A GRB afterglow with one smooth onset peak at early times is understood to result from such external shocks. Thus, we can determine the medium density distribution by fitting the onset peak appearing in the light curve of an early optical afterglow. We apply our model to 19 GRBs and find that their k values are in the range of 0.4-1.4, with a typical value of k ∼ 1, implying that this environment is neither a homogenous ISM with k = 0 nor a typical stellar wind with k = 2. This shows that the progenitors of these GRBs might have undergone a new mass-loss evolution

  3. Early Fermi Gamma-ray Space Telescope Observations of the Quasar 3C454.3

    Energy Technology Data Exchange (ETDEWEB)

    Abdo, A

    2009-05-07

    This is the first report of Fermi Gamma-ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope (LAT), covering 2008 July 7-October 6, indicate strong, highly variable {gamma}-ray emission with an average flux of {approx} 3 x 10{sup -6} photons cm{sup -2} s{sup -1}, for energies > 100 MeV. The {gamma}-ray flux is variable, with strong, distinct, symmetrically-shaped flares for which the flux increases by a factor of several on a time scale of about three days. This variability indicates a compact emission region, and the requirement that the source is optically thin to pair-production implies relativistic beaming with Doppler factor {delta} > 8, consistent with the values inferred from VLBI observations of superluminal expansion ({delta} {approx} 25). The observed {gamma}-ray spectrum is not consistent with a simple power-law, but instead steepens strongly above {approx} 2 GeV, and is well described by a broken power-law with photon indices of {approx} 2.3 and {approx} 3.5 below and above the break, respectively. This is the first direct observation of a break in the spectrum of a high luminosity blazar above 100 MeV, and it is likely direct evidence for an intrinsic break in the energy distribution of the radiating particles. Alternatively, the spectral softening above 2GeV could be due to -ray absorption via photonphoton pair production on the soft X-ray photon field of the host AGN, but such an interpretation would require the dissipation region to be located very close ({approx}< 100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.

  4. Learning and Developing as a University Teacher: Narratives of Early Career Academics in Estonia

    Science.gov (United States)

    Remmik, Marvi; Karm, Mari; Lepp, Liina

    2013-01-01

    In recent years the higher education context in Estonia, as in most European countries, has changed a lot. All changes have an impact on university teachers' practice and their work organisation, and are presenting new challenges. The current research aims at developing an understanding of Estonian early career academics' professional identity by…

  5. Matter-antimatter separation in the early universe by rotating black holes

    Science.gov (United States)

    Leahy, D. A.

    1981-01-01

    Consideration of the effect of rotating black holes evaporating early in the universe shows that they would have produced oppositely directed neutrino and antineutrino currents, which push matter and antimatter apart. This separation mechanism is, however, too feeble to account for a present baryon-to-photon ratio of 10 to the -9th, and has no significant observational consequences.

  6. Experimental and MCNP5 based evaluation of neutron and gamma flux in the irradiation ports of the University of Utah research reactor

    Directory of Open Access Journals (Sweden)

    Noble Brooklyn

    2012-01-01

    Full Text Available Neutron and gamma flux environment of various irradiation ports in the University of Utah training, research, isotope production, general atomics reactor were experimentally assessed and fully modeled using the MCNP5 code. The experimental measurements were based on the cadmium ratio in the irradiation ports of the reactor, flux profiling using nickel wire, and gamma dose measurements using thermo luminescence dosimeter. Full 3-D MCNP5 reactor model was developed to obtain the neutron flux distributions of the entire reactor core and to compare it with the measured flux focusing at the irradiation ports. Integration of all these analysis provided the updated comprehensive neutron-gamma flux maps of the existing irradiation facilities of the University of Utah TRIGA reactor.

  7. Cosmological Imprints of a Generalized Chaplygin Gas Model for the Early Universe

    Energy Technology Data Exchange (ETDEWEB)

    Bouhmadi-Lopez, Mariam; /Lisbon, CENTRA; Chen, Pisin; /Taiwan, Natl. Taiwan U. /KIPAC, Menlo Park /SLAC; Liu, Yen-Wei; /Taiwan, Natl. Taiwan U.

    2012-06-06

    We propose a phenomenological model for the early universe where there is a smooth transition between an early quintessence phase and a radiation-dominated era. The matter content is modeled by an appropriately modified Chaplygin gas for the early universe. We constrain the model observationally by mapping the primordial power spectrum of the scalar perturbations to the latest data of WMAP7. We compute as well the spectrum of the primordial gravitational waves as would be measured today. We show that the high frequencies region of the spectrum depends on the free parameter of the model and most importantly this region of the spectrum can be within the reach of future gravitational waves detectors.

  8. Early versus late Gamma Knife radiosurgery following transsphenoidal surgery for nonfunctioning pituitary macroadenomas: a multicenter matched-cohort study.

    Science.gov (United States)

    Pomeraniec, I Jonathan; Kano, Hideyuki; Xu, Zhiyuan; Nguyen, Brandon; Siddiqui, Zaid A; Silva, Danilo; Sharma, Mayur; Radwan, Hesham; Cohen, Jonathan A; Dallapiazza, Robert F; Iorio-Morin, Christian; Wolf, Amparo; Jane, John A; Grills, Inga S; Mathieu, David; Kondziolka, Douglas; Lee, Cheng-Chia; Wu, Chih-Chun; Cifarelli, Christopher P; Chytka, Tomas; Barnett, Gene H; Lunsford, L Dade; Sheehan, Jason P

    2017-10-27

    OBJECTIVE Gamma Knife radiosurgery (GKRS) is frequently used to treat residual or recurrent nonfunctioning pituitary macroadenomas. There is no consensus as to whether GKRS should be used early after surgery or if radiosurgery should be withheld until there is evidence of imaging-defined progression of tumor. Given the high incidence of adenoma progression after subtotal resection over time, the present study intended to evaluate the effect of timing of radiosurgery on outcome. METHODS This is a multicenter retrospective review of patients with nonfunctioning pituitary macroadenomas who underwent transsphenoidal surgery followed by GKRS from 1987 to 2015 at 9 institutions affiliated with the International Gamma Knife Research Foundation. Patients were matched by adenoma and radiosurgical parameters and stratified based on the interval between last resection and radiosurgery. Operative results, imaging data, and clinical outcomes were compared across groups following early (≤ 6 months after resection) or late (> 6 months after resection) radiosurgery. RESULTS After matching, 222 patients met the authors' study criteria (from an initial collection of 496 patients) and were grouped based on early (n = 111) or late (n = 111) GKRS following transsphenoidal surgery. There was a greater risk of tumor progression after GKRS (p = 0.013) and residual tumor (p = 0.038) in the late radiosurgical group over a median imaging follow-up period of 68.5 months. No significant difference in the occurrence of post-GKRS endocrinopathy was observed (p = 0.68). Thirty percent of patients without endocrinopathy in the early cohort developed new endocrinopathies during the follow-up period versus 27% in the late cohort (p = 0.84). Fourteen percent of the patients in the early group and 25% of the patients in the late group experienced the resolution of endocrine dysfunction after original presentation (p = 0.32). CONCLUSIONS In this study, early GKRS was associated with a lower risk of

  9. Radiosensitivity of the induction of early enzymes by. gamma. -irradiated T7-phages

    Energy Technology Data Exchange (ETDEWEB)

    Bopp, E

    1975-01-01

    The radiosensitivity of the ability of the bacteriophage T7 to produce polymerase and lysozyme during its reproduction cycle is investigated. B-cells of Escherichia coli were infected with /sup 60/Co-..gamma..-irradiated T7 phages. From the extracts of the cells opened by ultrasonic waves, the amount of enzymes produced is determined with the aid of special enzyme tests. The fraction of inactivated phages able to produce RNA polymerase is higher than the fraction with intact DNA double strands and higher than the fraction able to inject DNA. The lowest fraction is that of inactivated phages producing lysozyme.

  10. Low Doses of Gamma-Irradiation Induce an Early Bystander Effect in Zebrafish Cells Which Is Sufficient to Radioprotect Cells

    Science.gov (United States)

    Pereira, Sandrine; Malard, Véronique; Ravanat, Jean-Luc; Davin, Anne-Hélène; Armengaud, Jean; Foray, Nicolas; Adam-Guillermin, Christelle

    2014-01-01

    The term “bystander effect” is used to describe an effect in which cells that have not been exposed to radiation are affected by irradiated cells though various intracellular signaling mechanisms. In this study we analyzed the kinetics and mechanisms of bystander effect and radioadaptation in embryonic zebrafish cells (ZF4) exposed to chronic low dose of gamma rays. ZF4 cells were irradiated for 4 hours with total doses of gamma irradiation ranging from 0.01–0.1 Gy. In two experimental conditions, the transfer of irradiated cells or culture medium from irradiated cells results in the occurrence of DNA double strand breaks in non-irradiated cells (assessed by the number of γ-H2AX foci) that are repaired at 24 hours post-irradiation whatever the dose. At low total irradiation doses the bystander effect observed does not affect DNA repair mechanisms in targeted and bystander cells. An increase in global methylation of ZF4 cells was observed in irradiated cells and bystander cells compared to control cells. We observed that pre-irradiated cells which are then irradiated for a second time with the same doses contained significantly less γ-H2AX foci than in 24 h gamma-irradiated control cells. We also showed that bystander cells that have been in contact with the pre-irradiated cells and then irradiated alone present less γ-H2AX foci compared to the control cells. This radioadaptation effect is significantly more pronounced at the highest doses. To determine the factors involved in the early events of the bystander effect, we performed an extensive comparative proteomic study of the ZF4 secretomes upon irradiation. In the experimental conditions assayed here, we showed that the early events of bystander effect are probably not due to the secretion of specific proteins neither the oxidation of these secreted proteins. These results suggest that early bystander effect may be due probably to a combination of multiple factors. PMID:24667817

  11. Gamma knife radiosurgery for acoustic Schwannoma. Early effects and preservation of hearing

    Energy Technology Data Exchange (ETDEWEB)

    Hirato, Masafumi; Inoue, Hiroshi; Nakamura, Masaru; Ohye, Chihiro; Hirato, Junko [Gunma Univ., Maebashi (Japan). School of Medicine; Shibazaki, Tohru; Andou, Yoshitaka

    1995-10-01

    The effects of relatively low dose gamma knife irradiation on acoustic Schwannoma were evaluated. The signal intensity change and tumor shrinkage on magnetic resonance (MR) images, change in hearing, and complications in 28 patients (mean age 47.0{+-}13.6 yrs) were studied. Three patients had bilateral tumors. Six were already deaf when treated. The maximum tumor diameter was 35 mm. The mean dose delivered to the tumor was 12.1{+-}1.6 Gy at the periphery, and 25.2{+-}4.3 Gy at the center. The mean follow-up time was 16 months and the longest 24 months. Lowering of the MR signal intensity in the tumor center appeared after 3 months at earliest but generally after 6 months. Signs of tumor shrinkage appeared within 12 months on average. Cyst in the tumor enlarged rapidly after treatment in two patients. The percentage of hearing preservation was 85% (17/20) at 3 months, 80% (16/20) at 6 months, 72% (13/18) at 9 months, 75% (12/16) at 12 months, 67% (8/12) at 15 months, 60% (6/10) at 18 months, and 50% (2/4) at 24 months. Subtle changes in hearing were detected by speech tone audiometry. Temporary facial numbness and weakness was seen in one patient each. No patient had lower cranial nerve paresis. Relatively low dose gamma knife radiosurgery is effective in suppressing growth of acoustic Schwannoma with preservation of hearing. (author).

  12. Gamma knife radiosurgery for acoustic Schwannoma. Early effects and preservation of hearing

    International Nuclear Information System (INIS)

    Hirato, Masafumi; Inoue, Hiroshi; Nakamura, Masaru; Ohye, Chihiro; Hirato, Junko; Shibazaki, Tohru; Andou, Yoshitaka.

    1995-01-01

    The effects of relatively low dose gamma knife irradiation on acoustic Schwannoma were evaluated. The signal intensity change and tumor shrinkage on magnetic resonance (MR) images, change in hearing, and complications in 28 patients (mean age 47.0±13.6 yrs) were studied. Three patients had bilateral tumors. Six were already deaf when treated. The maximum tumor diameter was 35 mm. The mean dose delivered to the tumor was 12.1±1.6 Gy at the periphery, and 25.2±4.3 Gy at the center. The mean follow-up time was 16 months and the longest 24 months. Lowering of the MR signal intensity in the tumor center appeared after 3 months at earliest but generally after 6 months. Signs of tumor shrinkage appeared within 12 months on average. Cyst in the tumor enlarged rapidly after treatment in two patients. The percentage of hearing preservation was 85% (17/20) at 3 months, 80% (16/20) at 6 months, 72% (13/18) at 9 months, 75% (12/16) at 12 months, 67% (8/12) at 15 months, 60% (6/10) at 18 months, and 50% (2/4) at 24 months. Subtle changes in hearing were detected by speech tone audiometry. Temporary facial numbness and weakness was seen in one patient each. No patient had lower cranial nerve paresis. Relatively low dose gamma knife radiosurgery is effective in suppressing growth of acoustic Schwannoma with preservation of hearing. (author)

  13. Observing the Cosmic Microwave Background Radiation: A Unique Window on the Early Universe

    Science.gov (United States)

    Hinshaw, Gary; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics,of the early universe. Within the framework of inflationary dark matter models observations of the anisotropy on sub-degree angular scales will reveal the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of approx. 1100. The validity of inflationary models will be tested and, if agreement is found, accurate values for most of the key cosmological parameters will result. If disagreement is found, we will need to rethink our basic ideas about the physics of the early universe. I will present an overview of the physical processes at work in forming the anisotropy and discuss what we have already learned from current observations. I will conclude with a brief overview of the recently launched Microwave Anisotropy Probe (MAP) mission which will observe the anisotropy over the full sky with 0.21 degree angular resolution. At the time of this meeting, MAP will have just arrived at the L2 Lagrange point, marking the start of its observing campaign. The MAP hardware is being produced by Goddard in partnership with Princeton University.

  14. On the creation of scalar particles in an early stage of the Friedmann closed-universe

    International Nuclear Information System (INIS)

    Ishihara, Hideki; Nariai, Hidekazu.

    1982-03-01

    Under impetus of the two experimental studies on neutrinos by Reines-group and Lyubimov's, it has been shown by Zel'dovich et al. that the cosmological universe is closed, provided that the neutrino masses m sub(#betta#sub(i)) (i = e, μ, tau) satisfy the inequality μ/i m sub(#betta#sub(i))c 2 >= 20 ev. In a previous paper, the senior author dealt with the creation of scalar particles in an expanding universe with non-flat 3-space, but the case of a closed universe was practically ignored owing to the situation that the positive frequency part (in the sense of the author) of a quantized scalar field is not well-defined in that universe. In view of these circumstances, the creation of scalar particles in an early stage of the Friedmann closed-universe is searched for, on the supposition that the Fulling condition is preferable to define the positive frequency part in question near the early stage (as well as the later one). (author)

  15. Baryogenesis, dark matter and the maximal temperature of the early universe

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, Wilfried

    2012-12-15

    Mechanisms for the generation of the matter-antimatter asymmetry and dark matter strongly depend on the reheating temperature T{sub R}, the maximal temperature reached in the early universe. Forthcoming results from the LHC, low energy experiments, astrophysical observations and the Planck satellite will significantly constrain baryogenesis and the nature of dark matter, and thereby provide valuable information about the very early hot universe. At present, a wide range of reheating temperatures is still consistent with observations. We illustrate possible origins of matter and dark matter with four examples: moduli decay, electroweak baryogenesis, leptogenesis in the {nu}MSM and thermal leptogenesis. Finally, we discuss the connection between baryogenesis, dark matter and inflation in the context of supersymmetric spontaneous B-L breaking.

  16. Baryogenesis, dark matter and the maximal temperature of the early universe

    International Nuclear Information System (INIS)

    Buchmueller, Wilfried

    2012-12-01

    Mechanisms for the generation of the matter-antimatter asymmetry and dark matter strongly depend on the reheating temperature T R , the maximal temperature reached in the early universe. Forthcoming results from the LHC, low energy experiments, astrophysical observations and the Planck satellite will significantly constrain baryogenesis and the nature of dark matter, and thereby provide valuable information about the very early hot universe. At present, a wide range of reheating temperatures is still consistent with observations. We illustrate possible origins of matter and dark matter with four examples: moduli decay, electroweak baryogenesis, leptogenesis in the νMSM and thermal leptogenesis. Finally, we discuss the connection between baryogenesis, dark matter and inflation in the context of supersymmetric spontaneous B-L breaking.

  17. Background Information: Magnetars, Soft Gamma-Ray Repeaters and the Most Powerful Magnetic Fields in the Universe

    Science.gov (United States)

    1998-08-01

    bags" containing the accumulated history of this bursting activity. The study of these plerionic supernova remnants (detailed below) gives us a new and different perspective on the magnetar phenomena. SGR 0526-66: The Famous March 5 1979 Burst SGR 0526-66 lays claim to having produced the brightest gamma-ray burst ever observed: the famous March 5 1979 burst. Owing to the large number of satellites which saw this burst (10 in total) an accurate position could be determined. This put SGR 0526-66 on the edge of the supernova remnant N49 in the Large Magellanic Cloud 180,000 light years from our Sun. This should have been sufficient to convince everyone that the burst and the supernova remnant were associated. However, in 1979 astronomers were working under the misconception that all gamma-ray bursts came from a local (500 light years) population of neutron stars. This new piece of the puzzle didn't fit. Real progress in this area had to wait until the mid-1980's when soft gamma-ray repeaters were recognized as a distinct class of high energy transient and then in the early 1990's when SGR 1806-20 was tied to its supernova remnant (see below). The significance of two other important clues also went unnoticed in the early 1980's. The first was the large offset in the location of SGR 0526-66 from the center of the supernova remnant (i.e. its birthplace) and the second was a compact X-ray source at this same location. These observations, combined with the known age of the supernova remnant (5000 years), require that the magnetar be moving at a high speed and depositing energy into its surroundings as it goes. SGR 1806-20: A Magnetar Powers a Nebula While SGR 1806-20 was the most prolific burster in the 1980's, its true location wasn't known until it was detected by the Japanese X-ray ASCA satellite in 1993, verifying an earlier claim that it was associated with the supernova remnant G10.0-0.3. SGR 1806-20 lies at the center of this egg-shaped supernova remnant whose radio

  18. Inflaton and metric fluctuations in the early universe from a 5D vacuum state

    Energy Technology Data Exchange (ETDEWEB)

    Membiela, Agustin [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350 (7600) Mar del Plata (Argentina)]. E-mail: membiela@argentina.com; Bellini, Mauricio [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350 (7600) Mar del Plata (Argentina) and Consejo Nacional de Ciencia y Tecnologia (CONICET) (Argentina)]. E-mail: mbellini@mdp.edu.ar

    2006-04-20

    In this Letter we complete a previously introduced formalism to study the gauge-invariant metric fluctuations from a noncompact Kaluza-Klein theory of gravity, to study the evolution of the early universe. The evolution of both, metric and inflaton field fluctuations are reciprocally related. We obtain that <{delta}{rho}>/{rho}{sub b} depends on the coupling of {phi} with {delta}{phi} and the spectral index of its spectrum is 0.9483

  19. Inflaton and metric fluctuations in the early universe from a 5D vacuum state

    Science.gov (United States)

    Membiela, Agustin; Bellini, Mauricio

    2006-04-01

    In this Letter we complete a previously introduced formalism to study the gauge-invariant metric fluctuations from a noncompact Kaluza Klein theory of gravity, to study the evolution of the early universe. The evolution of both, metric and inflaton field fluctuations are reciprocally related. We obtain that /ρ depends on the coupling of Φ with δφ and the spectral index of its spectrum is 0.9483

  20. Inflaton and metric fluctuations in the early universe from a 5D vacuum state

    International Nuclear Information System (INIS)

    Membiela, Agustin; Bellini, Mauricio

    2006-01-01

    In this Letter we complete a previously introduced formalism to study the gauge-invariant metric fluctuations from a noncompact Kaluza-Klein theory of gravity, to study the evolution of the early universe. The evolution of both, metric and inflaton field fluctuations are reciprocally related. We obtain that /ρ b depends on the coupling of Φ with δφ and the spectral index of its spectrum is 0.9483 1 <1

  1. On the chaoticity of active-sterile neutrino oscillations in the early universe

    DEFF Research Database (Denmark)

    Braad, Poul-Erik; Hannestad, Steen

    2000-01-01

    We have investigated the evolution of the neutrino asymmetry in active-sterile neutrino oscillations in the early universe. We find that there are large regions of parameter space where the asymmetry is extremely sensitive to variations in the initial asymmetry as well as the external parameters ...... asymmetry is stochastic. We discuss the implications of our findings for Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB)....

  2. Were all white holes in the early Universe converted into black holes?

    International Nuclear Information System (INIS)

    Dey, T.K.; Banerji, S.

    1991-01-01

    It has been claimed that in the early Universe any white hole must have been converted to a black hole. But taking the simple case of an expanding homogeneous dust sphere colliding with a homogeneous spherical shell of dust which are mutually noninteracting, we find that the mean motion of the combined system will be expanding or contracting to a distant observer according as the combined radius at the instant of collision is less than or greater than the Schwarzschild radius

  3. Identification of early Llandovery (Silurian) anoxic palaeo-depressions at the western margin of the Murzuq Basin (southwest Libya), based on gamma-ray spectrometry in surface exposures

    Czech Academy of Sciences Publication Activity Database

    Fello, N.; Lüning, S.; Štorch, Petr; Redfern, J.

    2006-01-01

    Roč. 11, č. 3 (2006), s. 101-118 ISSN 1025-6059 R&D Projects: GA ČR GA205/99/1322 Institutional research plan: CEZ:AV0Z30130516 Keywords : postglacial anoxy * early Llandovery * Murzuq Basin * palaeo-depressions * gamma-spectrometry Subject RIV: DB - Geology ; Mineralogy

  4. Is the Universe expanding? Fritz Zwicky and the early tired-light hypothesis

    Science.gov (United States)

    Kragh, Helge

    2017-04-01

    The recognition that the Universe is in a state of expansion is a milestone in modern astronomy and cosmology. The discovery dates from the early 1930s but was not unanimously accepted by either astronomers or physicists. The relativistic theory of the expanding Universe rested empirically on the redshift-distance law established by Edwin Hubble in 1929. However, although the theory offered a natural explanation of the observed galactic redshifts, these could be explained also on the assumption of a Static Universe. This was what Fritz Zwicky did when he introduced the idea of "tired light" in the fall of 1929. Hypotheses of a similar kind were proposed by several other scientists but their impact on mainstream astronomy and cosmology was limited. The paper offers a survey of tired-light hypotheses in the 1930s and briefly alludes to the later development.

  5. Supersonic gas streams enhance the formation of massive black holes in the early universe.

    Science.gov (United States)

    Hirano, Shingo; Hosokawa, Takashi; Yoshida, Naoki; Kuiper, Rolf

    2017-09-29

    The origin of super-massive black holes in the early universe remains poorly understood. Gravitational collapse of a massive primordial gas cloud is a promising initial process, but theoretical studies have difficulty growing the black hole fast enough. We report numerical simulations of early black hole formation starting from realistic cosmological conditions. Supersonic gas motions left over from the Big Bang prevent early gas cloud formation until rapid gas condensation is triggered in a protogalactic halo. A protostar is formed in the dense, turbulent gas cloud, and it grows by sporadic mass accretion until it acquires 34,000 solar masses. The massive star ends its life with a catastrophic collapse to leave a black hole-a promising seed for the formation of a monstrous black hole. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  6. UBAT of UFFO/ Lomonosov: The X-Ray Space Telescope to Observe Early Photons from Gamma-Ray Bursts

    Science.gov (United States)

    Jeong, S.; Panasyuk, M. I.; Reglero, V.; Connell, P.; Kim, M. B.; Lee, J.; Rodrigo, J. M.; Ripa, J.; Eyles, C.; Lim, H.; Gaikov, G.; Jeong, H.; Leonov, V.; Chen, P.; Castro-Tirado, A. J.; Nam, J. W.; Svertilov, S.; Yashin, I.; Garipov, G.; Huang, M.-H. A.; Huang, J.-J.; Kim, J. E.; Liu, T.-C.; Petrov, V.; Bogomolov, V.; Budtz-Jørgensen, C.; Brandt, S.; Park, I. H.

    2018-02-01

    The Ultra-Fast Flash Observatory (UFFO) Burst Alert and Trigger Telescope (UBAT) has been designed and built for the localization of transient X-ray sources such as Gamma Ray Bursts (GRBs). As one of main instruments in the UFFO payload onboard the Lomonosov satellite (hereafter UFFO/ Lomonosov), the UBAT's roles are to monitor the X-ray sky, to rapidly locate and track transient sources, and to trigger the slewing of a UV/optical telescope, namely Slewing Mirror Telescope (SMT). The SMT, a pioneering application of rapid slewing mirror technology has a line of sight parallel to the UBAT, allowing us to measure the early UV/optical GRB counterpart and study the extremely early moments of GRB evolution. To detect X-rays, the UBAT utilizes a 191.1 cm2 scintillation detector composed of Yttrium Oxyorthosilicate (YSO) crystals, Multi-Anode Photomultiplier Tubes (MAPMTs), and associated electronics. To estimate a direction vector of a GRB source in its field of view, it employs the well-known coded aperture mask technique. All functions are written for implementation on a field programmable gate array to enable fast triggering and to run the device's imaging algorithms. The UFFO/ Lomonosov satellite was launched on April 28, 2016, and is now collecting GRB observation data. In this study, we describe the UBAT's design, fabrication, integration, and performance as a GRB X-ray trigger and localization telescope, both on the ground and in space.

  7. Ground based THz Spectroscopy of Obscured Starbursts in the Early Universe enabled by the 2nd generation Redshift (z) & Early Universe Spectrometer (ZEUS-2)

    Science.gov (United States)

    Vishwas, Amit; Stacey, Gordon; Nikola, Thomas; Ferkinhoff, Carl; Parshley, Stephen; Schoenwald, Justin; Lamarche, Cody James; Higdon, James; Higdon, Sarah; Brisbin, Drew; Güesten, Rolf; Weiss, Axel; Menten, Karl; Irwin, Kent; Cho, Hsiao-Mei; Niemack, Michael; Hilton, Gene; Hubmayr, Johannes; Amiri, Mandana; Halpern, Mark; Wiebe, Donald; Hasselfield, Matthew; Ade, Peter; Tucker, Carole

    2018-01-01

    Galaxies were surprisingly dusty in the early Universe, with more than half of the light emitted from stars being absorbed by dust within the system and re-radiated into far infrared (FIR, ~50-150μm) wavelengths. Dusty star forming galaxies (DSFGs) dominate the co-moving star formation rate density of the Universe that peaks around redshift, z~2, making it compelling to study them in rest frame FIR bands. From galaxies at z > 1, the FIR line emission from abundant ions like [O III], [C II] and [N II], are redshifted into the short sub-mm telluric windows. My thesis work is based on building and deploying the 2nd Generation Redshift (z) and Early Universe Spectrometer (ZEUS-2), a long-slit, echelle grating spectrometer optimized to study broad (Δv = 300km/s) spectral lines from galaxies in the 200-650µm telluric windows using TES bolometers. These far-IR lines being extinction free and major coolants of the gas heated by (young) massive stars, are powerful probes of the physical conditions of the gas and the stellar radiation field. I present results from our survey of the [O III] 88µm line in galaxies at redshift, z ~ 2.8 to 4.6, with ZEUS-2 at the Atacama Pathfinder Experiment (APEX) Telescope. To interpret our observations along with ancillary data from optical to radio facilities, we apply photoionization models for HII regions and Photo Dissociation Region (PDR) models and confirm that the galaxies host substantial ongoing obscured star formation. The presence of doubly ionized oxygen suggests hard radiation fields and hence, elevated ionization parameters that can only be accounted for by a large population of massive stars formed during the ongoing starburst, that contribute a large fraction of the infrared luminosity. This study highlights the use of FIR line emission to trace the assembly of current day massive galaxies, conditions of star formation and details of their stellar populations. The construction and operation of ZEUS-2 were funded by NSF ATI

  8. Effects of low dose gamma radiation on the early growth of red pepper and the resistance to subsquent high dose of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. S.; Baek, M. H.; Kim, D. H.; Lee, Y. K. [KAERI, Taejon (Korea, Republic of); Lee, Y. B. [Chungnam National Univ., Taejon (Korea, Republic of)

    2001-05-01

    Red pepper (capsicum annuum L. cv. Jokwang and cv. Johong) seeds were irradiated with the dose of 0{approx}50 Gy to investigated the effect of the low dose gamma radiation on the early growth and resistance to subsequent high dose of radiation. The effect of the low dose gamma radiation on the early growth and resistance to subsequenct high dose of radiation were enhanced in Johong cultivar but not in Jokwang cultivar. Germination rate and early growth of Johong cultivar were noticeably increased at 4 Gy-, 8 Gy- and 20 Gy irradiation group. Resistance to subsequent high dose of radiation of Johong cultivar were increased at almost all of the low dose irradiation group. Especially it was highest at 4 Gy irradiation group. The carotenoid contents and enzyme activity on the resistance to subsequent high dose of radiation of Johong cultivar were increased at the 4 Gy and 8 Gy irradiation group.

  9. UFFO/Lomonosov: The Payload for the Observation of Early Photons from Gamma Ray Bursts

    DEFF Research Database (Denmark)

    Park, I. H.; Panasyuk, M. I.; Reglero, V.

    2018-01-01

    . Fast response measurements of the optical emission of GRB will be made by a Slewing Mirror Telescope (SMT), a key instrument of the payload, which will open a new frontier in transient studies by probing the early optical rise of GRBs with a response time in seconds for the first time. The SMT employs...... a rapidly slewing mirror to redirect the optical axis of the telescope to a GRB position prior determined by the UFFO Burst Alert Telescope (UBAT), the other onboard instrument, for the observation and imaging of X-rays. UFFO/Lomonosov was launched successfully from Vostochny, Russia on April 28, 2016...

  10. UFFO/ Lomonosov: The Payload for the Observation of Early Photons from Gamma Ray Bursts

    Science.gov (United States)

    Park, I. H.; Panasyuk, M. I.; Reglero, V.; Chen, P.; Castro-Tirado, A. J.; Jeong, S.; Bogomolov, V.; Brandt, S.; Budtz-Jørgensen, C.; Chang, S.-H.; Chang, Y. Y.; Chen, C.-R.; Chen, C.-W.; Choi, H. S.; Connell, P.; Eyles, C.; Gaikov, G.; Garipov, G.; Huang, J.-J.; Huang, M.-H. A.; Jeong, H. M.; Kim, J. E.; Kim, M. B.; Kim, S.-W.; Lee, H. K.; Lee, J.; Lim, H.; Lin, C.-Y.; Liu, T.-C.; Nam, J. W.; Petrov, V.; Ripa, J.; Rodrigo, J. M.; Svertilov, S.; Wang, M.-Z.; Yashin, I.

    2018-02-01

    The payload of the UFFO (Ultra-Fast Flash Observatory)-pathfinder now onboard the Lomonosov spacecraft (hereafter UFFO/ Lomonosov) is a dedicated instrument for the observation of GRBs. Its primary aim is to capture the rise phase of the optical light curve, one of the least known aspects of GRBs. Fast response measurements of the optical emission of GRB will be made by a Slewing Mirror Telescope (SMT), a key instrument of the payload, which will open a new frontier in transient studies by probing the early optical rise of GRBs with a response time in seconds for the first time. The SMT employs a rapidly slewing mirror to redirect the optical axis of the telescope to a GRB position prior determined by the UFFO Burst Alert Telescope (UBAT), the other onboard instrument, for the observation and imaging of X-rays. UFFO/Lomonosov was launched successfully from Vostochny, Russia on April 28, 2016, and will begin GRB observations after completion of functional checks of the Lomonosov spacecraft. The concept of early GRB photon measurements with UFFO was reported in 2012. In this article, we will report in detail the first mission, UFFO/Lomonosov, for the rapid response to GRB observations.

  11. Awareness of Skin Cancer, Prevention, and Early Detection among Turkish University Students

    Directory of Open Access Journals (Sweden)

    Ziyafet Ugurlu

    2016-01-01

    Full Text Available Objective: The aim of this study was to determine the awareness about skin cancer, prevention, and early detection among university students. Methods: This descriptive cross-sectional study was carried out with 404 students in a university located in Ankara, the capital city of Turkey. A 35-item questionnaire was used for data collection. Results: Less than half of the students (37.9% had knowledge about skin cancer mostly through the internet (24.5% and media (24.1%. Half of them aware of the risk factors; mostly as avoiding direct exposure to the Sun between 10 am and 4 pm (45.3%; smoking and alcohol (38.4%; having fair skin color (34.9%; and ultraviolet light exposure (25.7%. Only one-third of them (32.9% are knowledgeable about skin cancer signs and symptoms, such as a change in color and appearance of the nevus/moles (24%. The majority of the responders (77.3% did not know about screening tests for skin cancer and only 18 (4.5% students were practicing skin self-examination. Conclusions: This study showed a lack of knowledge about skin cancer, prevention, and early detection among university students and reported the need for educational interventions to raise awareness in this target group.

  12. THE ROLE OF DUST IN THE EARLY UNIVERSE. I. PROTOGALAXY EVOLUTION

    International Nuclear Information System (INIS)

    Yamasawa, Daisuke; Habe, Asao; Kozasa, Takashi; Nozawa, Takaya; Nomoto, Ken'ichi; Hirashita, Hiroyuki; Umeda, Hideyuki

    2011-01-01

    We develop one-zone galaxy formation models in the early universe, taking into account dust formation and evolution by supernova (SN) explosions. We focus on the time evolution of dust size distribution, because H 2 formation on the dust surface plays a critical role in the star formation process in the early universe. In the model, we assume that star formation rate (SFR) is proportional to the total amount of H 2 . We consistently treat (1) the formation and size evolution of dust, (2) the chemical reaction networks including H 2 formation both on the surface of dust and in gas phase, and (3) the SFR in the model. First, we find that, because of dust destruction due to both reverse and forward shocks driven by SNe, H 2 formation is more suppressed than in situations without such dust destruction. At the galaxy age of ∼0.8 Gyr, for galaxy models with virial mass M vir = 10 9 M sun and formation redshift z vir = 10, the molecular fraction is 2.5 orders of magnitude less in the model with dust destruction by both shocks than that in the model without dust destruction. Second, we show that the H 2 formation rate strongly depends on the interstellar medium (ISM) density around SN progenitors. The SFR in higher ISM density is lower, since dust destruction by reverse shocks is more effective in higher ISM density. We conclude that not only the amount but also the size distribution of dust related to star formation activity strongly affects the evolution of galaxies in the early universe.

  13. Rapid growth of seed black holes in the early universe by supra-exponential accretion.

    Science.gov (United States)

    Alexander, Tal; Natarajan, Priyamvada

    2014-09-12

    Mass accretion by black holes (BHs) is typically capped at the Eddington rate, when radiation's push balances gravity's pull. However, even exponential growth at the Eddington-limited e-folding time t(E) ~ few × 0.01 billion years is too slow to grow stellar-mass BH seeds into the supermassive luminous quasars that are observed when the universe is 1 billion years old. We propose a dynamical mechanism that can trigger supra-exponential accretion in the early universe, when a BH seed is bound in a star cluster fed by the ubiquitous dense cold gas flows. The high gas opacity traps the accretion radiation, while the low-mass BH's random motions suppress the formation of a slowly draining accretion disk. Supra-exponential growth can thus explain the puzzling emergence of supermassive BHs that power luminous quasars so soon after the Big Bang. Copyright © 2014, American Association for the Advancement of Science.

  14. Introduction to the theory of the early universe hot Big Bang theory

    CERN Document Server

    Rubakov, Valery A

    2018-01-01

    This book is written from the viewpoint that a deep connection exists between cosmology and particle physics. It presents the results and ideas on both the homogeneous and isotropic Universe at the hot stage of its evolution and in later stages. The main chapters describe in a systematic and pedagogical way established facts and concepts on the early and the present Universe. The comprehensive treatment, hence, serves as a modern introduction to this rapidly developing field of science. To help in reading the chapters without having to constantly consult other texts, essential materials from General Relativity and the theory of elementary particles are collected in the appendices. Various hypotheses dealing with unsolved problems of cosmology, and often alternative to each other, are discussed at a more advanced level. These concern dark matter, dark energy, matter–antimatter asymmetry, etc. Particle physics and cosmology underwent rapid development between the first and the second editions of this book. I...

  15. Neutrinos in the Early Universe, Kalb-Ramond Torsion and Matter-Antimatter Asymmetry

    Directory of Open Access Journals (Sweden)

    Mavromatos Nick E.

    2014-04-01

    Full Text Available The generation of a matter-antimatter asymmetry in the universe may be induced by the propagation of fermions in non-trivial, spherically asymmetric (and hence Lorentz violating gravitational backgrounds. Such backgrounds may characterise the epoch of the early universe. The key point in these models is that the background induces di_erent dispersion relations, hence populations, between fermions and antifermions, and thus CPT Violation (CPTV appears in thermal equilibrium. Species populations may freeze out leading to leptogenesis and baryogenesis. We consider here a string-inspired scenario, in which the CPTV is associated with a cosmological background with torsion provided by the Kalb-Ramond (KR antisymemtric tensor field of the string gravitational multiplet. In a four-dimensional space time this field is dual to a pseudoscalar “axionlike” field. The mixing of the KR field with an ordinary axion field can lead to the generation of a Majorana neutrino mass.

  16. AGN feedback through UFO and galaxy-wide winds in the early Universe

    Science.gov (United States)

    Feruglio, C.; Piconcelli, E.; Bischetti, M.; Zappacosta, L.; Fiore, F.

    2017-10-01

    AGN feedback through massive molecular winds is today routinely observed in local AGN host galaxies, but not as such in the early universe. I will present the first evidence for a massive, AGN-driven molecular wind in the z 4 QSO APM08279, which also hosts the most well studied and persistent nuclear semi-raltivistic wind (UFO). This observation directly probes the expansion mechanism of a nuclear wind into the ISM on galaxy wide scales, that so far was constrained by a couple of other objects only (Feruglio et al. 2015, Tombesi et al. 2015). This result also opens the path toward the exploration of molecular AGN-driven winds at early epochs, close after the end of the Epoch of Reionisation (EoR).

  17. Coherent Active-Sterile Neutrino Flavor Transformation in the Early Universe

    Science.gov (United States)

    Kishimoto, Chad T.; Fuller, George M.; Smith, Christel J.

    2006-10-01

    We solve the problem of coherent Mikheyev-Smirnov-Wolfenstein resonant active-to-sterile neutrino flavor conversion driven by an initial lepton number in the early Universe. We find incomplete destruction of the lepton number in this process and a sterile neutrino energy distribution with a distinctive cusp and high energy tail. These features imply alteration of the nonzero lepton number primordial nucleosynthesis paradigm when there exist sterile neutrinos with rest masses ms˜1eV. This could result in better light element probes of (constraints on) these particles.

  18. Coherent Active-Sterile Neutrino Flavor Transformation in the Early Universe

    International Nuclear Information System (INIS)

    Kishimoto, Chad T.; Fuller, George M.; Smith, Christel J.

    2006-01-01

    We solve the problem of coherent Mikheyev-Smirnov-Wolfenstein resonant active-to-sterile neutrino flavor conversion driven by an initial lepton number in the early Universe. We find incomplete destruction of the lepton number in this process and a sterile neutrino energy distribution with a distinctive cusp and high energy tail. These features imply alteration of the nonzero lepton number primordial nucleosynthesis paradigm when there exist sterile neutrinos with rest masses m s ∼1 eV. This could result in better light element probes of (constraints on) these particles

  19. Constraining antimatter domains in the early universe with big bang nucleosynthesis.

    Science.gov (United States)

    Kurki-Suonio, H; Sihvola, E

    2000-04-24

    We consider the effect of a small-scale matter-antimatter domain structure on big bang nucleosynthesis and place upper limits on the amount of antimatter in the early universe. For small domains, which annihilate before nucleosynthesis, this limit comes from underproduction of 4He. For larger domains, the limit comes from 3He overproduction. Since most of the 3He from &pmacr; 4He annihilation are themselves annihilated, the main source of primordial 3He is the photodisintegration of 4He by the electromagnetic cascades initiated by the annihilation.

  20. The early response of pineal N-acetyltransferase activity, melatonin and catecholamine levels in rats irradiated with gamma rays

    International Nuclear Information System (INIS)

    Kassayova, M.; Ahlersova, E.; Ahlers, I.; Pastorova, B.

    1995-01-01

    Male Wistar rats adapted to an artificial light-dark regimen were whole-body gamma-irradiated with a dose of 14.35 Gy. Irradiation, sham-irradiation and decapitation 30, 60 and 120 min after the exposure were performed between 2000 h and 0100 h in the darkness. The serotonin N-acetyltransferase activity (NAT), the concentration of melatonin and corticosterone were also determined. Ionizing radiation did not change the activity of NAT, the key enzyme of melatonin synthesis; however, it decreased the concentration of pineal melatonin. The concentration of pineal dopamine and norepinephrine decreased 30 and 120 min after exposure, while the concentration of epinephrine was elevated 30 min after irradiation, though later it was markedly decreased. The serum melatonin level was not changed but an increase in corticosterone level was observed. In the early period after exposure a decrease in pineal melatonin occurred, accompanied by a decrease in pineal catecholamines. On the contrary, in the phase of developed radiation injury the signs of increased melatonin synthesis were observed on days 3 and 4 after the exposure. (author) 6 figs., 25 refs

  1. Early results utilizing high-energy fission product gamma rays to detect fissionable material in cargo

    International Nuclear Information System (INIS)

    Slaughter, D.R.; Accatino, M.R.; Alford, O.J.; Bernstein, A.; Descalle, M.; Gosnell, T.B.; Hall, J.M.; Loshak, A.; Manatt, D.R.; McDowell, M.R.; Moore, T.L.; Petersen, D.C.; Pohl, B.A.; Pruet, J.A.; Prussin, S.G.

    2004-01-01

    Full text: A concept for detecting the presence of special nuclear material ( 235 U or 239 Pu) concealed in inter modal cargo containers is described. It is based on interrogation with a pulsed beam of 6-8 MeV neutrons and fission events are identified between beam pulses by their β-delayed neutron emission or β -delayed high-energy γ-radiation. The high-energy γ-ray signature is being employed for the first time. Fission product γ-rays above 3 MeV are distinct from natural radioactivity and from nearly all of the induced activity in a normal cargo. High-energy γ-radiation is nearly 10X more abundant than the delayed neutrons and penetrates even thick cargo's readily. The concept employs two large (8x20 ft) arrays of liquid scintillation detectors that have high efficiency for the detection of both delayed neutrons and delayed γ-radiation. Detector backgrounds and potential interferences with the fission signature radiation have been identified and quantified. This information, together with predicted signature strength, has been applied to the estimation of detection probability for the nuclear material and estimation of false alarm rates. This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48

  2. Early morphologic and quantitative changes in mouse peripheral blood lymphocytes after low dose gamma-irradiation

    International Nuclear Information System (INIS)

    Gitsov, L.; Byrneva, V.; Goranov, I.

    1979-01-01

    The study was undertaken in an effort to establish differences in the radiosensitivity of peripheral blood lymphocytes, as a possible test for evaluation of early and discrete radiation injury. Sexually mature mice of BAIB/c line were X-irradiated with doses of 50 and 250 rad. The animals were sacrificed by blood letting 24 hours after irradiation, but 30 minutes before this each mouse was heparinized. Smears were prepared from the enriched pooled leucocyte suspensions, obtained by dextran sedimentation of the red cells. The preparations were stained with toluidin blue by the methods of Smetana and Pappenheim. Cell size, clasmatosis, nucleolar structure and degree of cytoplasmic metachromasia were determined. It was found that the lymphocytogram of animals irradiated with 50 rad was characterized by high percentage of small lymphocytes, most of them with dispersed nuclear ribonucleoproteins and minimal clasmatose activity. Irradiation with 100 rad induced a characteristical rise in lymphocyte clasmatose activity and decrease in the number of small lymphocytes. The nucleoli were bright and well delineated. The lymphocytogram of animals irradiated with higher doses (150 and 250 rad) was characterized by predomination of large lymphocytes and hyperbasophilic forms with well preserved bright nucleoli. The percentage of lymphocates with clasmatosis was below the control value. (A.B.)

  3. Effects of low dose {gamma} radiation on early growth and physiological activities of radish (raphanus sativus L.) and the reduction of ultraviolet-B stress

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. S.; Lee, Y. K.; Lee, H. Y.; Baek, M. H.; Yoo, J. C. [KAERI, Taejon (Korea, Republic of)

    2002-10-01

    The effect of low dose {gamma} radiation on early growth and photosynthesis in radish plant was studied. The seedling height of radish was stimulated in plants grown from seeds irradiated with the low dose of 10 Gy. The O{sub 2} evolution in the 10 Gy irradiation group was 1.2 times greater than in the control. The catalase and peroxidase activity of radish leaves grown from seeds irradiated with {gamma} radiation were increased at 10 Gy irradiation group as the superoxide dismutase activity of leaves was. To investigate the effect of low dose {gamma} radiation on response to UV-B stress, UV-B was given at the intensity of 1 W{center_dot} m{sup -2} to the detached leaves. Pmax was decreased with increasing illumination time by 76% in the control, while decreased by 75% in the 10 Gy irradiation group. The photochemical yield of PSII, estimated as Fv/Fm, was decreased with increasing illumination time by 75% after 4 hours while Fv/Fm in the 10 Gy irradiation group was decreased by 69% of inhibition, indicating that the low dose {gamma} radiation retarded the deteriorative effect of UV-B on PSII. The initial fluorescence (Fo) was slightly increased with increasing illumination time, while the maximal fluorescence (Fm) was decreased. These results showed the positive effect of low dose {gamma} radiation on the seedling growth and the reduction of the deteriorative effect of UV-B stress on photosynthesis in radish plant.

  4. Vacuum stability in the early universe and the backreaction of classical gravity.

    Science.gov (United States)

    Markkanen, Tommi

    2018-03-06

    In the case of a metastable electroweak vacuum, the quantum corrected effective potential plays a crucial role in the potential instability of the standard model. In the early universe, in particular during inflation and reheating, this instability can be triggered leading to catastrophic vacuum decay. We discuss how the large space-time curvature of the early universe can be incorporated in the calculation and in many cases significantly modify the flat space prediction. The two key new elements are the unavoidable generation of the non-minimal coupling between the Higgs field and the scalar curvature of gravity and a curvature induced contribution to the running of the constants. For the minimal set up of the standard model and a decoupled inflation sector we show how a metastable vacuum can lead to very tight bounds for the non-minimal coupling. We also discuss a novel and very much related dark matter generation mechanism.This article is part of the Theo Murphy meeting issue 'Higgs cosmology'. © 2018 The Author(s).

  5. Can superconducting cosmic strings piercing seed black holes generate supermassive black holes in the early universe?

    Energy Technology Data Exchange (ETDEWEB)

    Lake, Matthew J. [The Institute for Fundamental Study, ' ' The Tah Poe Academia Institute' ' , Naresuan University, Phitsanulok (Thailand); Thailand Center of Excellence in Physics, Ministry of Education, Bangkok (Thailand); Harko, Tiberiu [Department of Physics, Babes-Bolyai University, Cluj-Napoca (Romania); Department of Mathematics, University College London (United Kingdom)

    2017-10-15

    The discovery of a large number of supermassive black holes (SMBH) at redshifts z > 6, when the Universe was only 900 million years old, raises the question of how such massive compact objects could form in a cosmologically short time interval. Each of the standard scenarios proposed, involving rapid accretion of seed black holes or black hole mergers, faces severe theoretical difficulties in explaining the short-time formation of supermassive objects. In this work we propose an alternative scenario for the formation of SMBH in the early Universe, in which energy transfer from superconducting cosmic strings piercing small seed black holes is the main physical process leading to rapid mass increase. As a toy model, the accretion rate of a seed black hole pierced by two antipodal strings carrying constant current is considered. Using an effective action approach, which phenomenologically incorporates a large class of superconducting string models, we estimate the minimum current required to form SMBH with masses of order M = 2 x 10{sup 9} M {sub CircleDot} by z = 7.085. This corresponds to the mass of the central black hole powering the quasar ULAS J112001.48+064124.3 and is taken as a test case scenario for early-epoch SMBH formation. For GUT scale strings, the required fractional increase in the string energy density, due to the presence of the current, is of order 10{sup -7}, so that their existence remains consistent with current observational bounds on the string tension. In addition, we consider an ''exotic'' scenario, in which an SMBH is generated when a small seed black hole is pierced by a higher-dimensional F-string, predicted by string theory. We find that both topological defect strings and fundamental strings are able to carry currents large enough to generate early-epoch SMBH via our proposed mechanism. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Encouraging entrepreneurship in university labs: Research activities, research outputs, and early doctorate careers

    Science.gov (United States)

    2017-01-01

    This paper investigates how the encouragement of entrepreneurship within university research labs relates with research activities, research outputs, and early doctorate careers. Utilizing a panel survey of 6,840 science & engineering doctoral students at 39 R1 research universities, this study shows that entrepreneurship is widely encouraged across university research labs, ranging from 54% in biomedical engineering to 18% in particle physics, while only a small share of labs openly discourage entrepreneurship, from approximately 3% in engineering to approximately 12% in the life sciences. Within fields, there is no difference between labs that encourage entrepreneurship and those that do not with respect to basic research activity and the number of publications. At the same time, labs that encourage entrepreneurship are significantly more likely to report invention disclosures, particularly in engineering where such labs are 41% more likely to disclose inventions. With respect to career pathways, PhDs students in labs that encourage entrepreneurship do not differ from other PhDs in their interest in academic careers, but they are 87% more likely to be interested in careers in entrepreneurship and 44% more likely to work in a startup after graduation. These results persist even when accounting for individuals’ pre-PhD interest in entrepreneurship and the encouragement of other non-academic industry careers. PMID:28178270

  7. Encouraging entrepreneurship in university labs: Research activities, research outputs, and early doctorate careers.

    Science.gov (United States)

    Roach, Michael

    2017-01-01

    This paper investigates how the encouragement of entrepreneurship within university research labs relates with research activities, research outputs, and early doctorate careers. Utilizing a panel survey of 6,840 science & engineering doctoral students at 39 R1 research universities, this study shows that entrepreneurship is widely encouraged across university research labs, ranging from 54% in biomedical engineering to 18% in particle physics, while only a small share of labs openly discourage entrepreneurship, from approximately 3% in engineering to approximately 12% in the life sciences. Within fields, there is no difference between labs that encourage entrepreneurship and those that do not with respect to basic research activity and the number of publications. At the same time, labs that encourage entrepreneurship are significantly more likely to report invention disclosures, particularly in engineering where such labs are 41% more likely to disclose inventions. With respect to career pathways, PhDs students in labs that encourage entrepreneurship do not differ from other PhDs in their interest in academic careers, but they are 87% more likely to be interested in careers in entrepreneurship and 44% more likely to work in a startup after graduation. These results persist even when accounting for individuals' pre-PhD interest in entrepreneurship and the encouragement of other non-academic industry careers.

  8. Role of the cosmological constant in the holographic description of the early universe

    International Nuclear Information System (INIS)

    Myung, Yun Soo

    2004-01-01

    We investigate the role of the cosmological constant in the holographic description of a radiation-dominated universe C 2 /R 4 with a positive cosmological constant Λ. In order to understand the nature of cosmological term, we first study the Newtonian cosmology. Here we find two aspects of the cosmological term: entropy (Λ→S Λ ) and energy (Λ→E Λ ). Also we solve the Friedmann equation parametrically to obtain another role. In the presence of the cosmological constant, the solutions are described by the Weierstrass elliptic functions on torus and have modular properties. In this case one may expect to have a two-dimensional Cardy entropy formula but the cosmological constant plays a role of the modular parameter τ(C 2 ,Λ) of torus. Consequently, the entropy concept of the cosmological constant is very suitable for establishing the holographic entropy bounds in the early universe. This contrasts to the role of the cosmological constant as a dark energy in the present universe

  9. Encouraging entrepreneurship in university labs: Research activities, research outputs, and early doctorate careers.

    Directory of Open Access Journals (Sweden)

    Michael Roach

    Full Text Available This paper investigates how the encouragement of entrepreneurship within university research labs relates with research activities, research outputs, and early doctorate careers. Utilizing a panel survey of 6,840 science & engineering doctoral students at 39 R1 research universities, this study shows that entrepreneurship is widely encouraged across university research labs, ranging from 54% in biomedical engineering to 18% in particle physics, while only a small share of labs openly discourage entrepreneurship, from approximately 3% in engineering to approximately 12% in the life sciences. Within fields, there is no difference between labs that encourage entrepreneurship and those that do not with respect to basic research activity and the number of publications. At the same time, labs that encourage entrepreneurship are significantly more likely to report invention disclosures, particularly in engineering where such labs are 41% more likely to disclose inventions. With respect to career pathways, PhDs students in labs that encourage entrepreneurship do not differ from other PhDs in their interest in academic careers, but they are 87% more likely to be interested in careers in entrepreneurship and 44% more likely to work in a startup after graduation. These results persist even when accounting for individuals' pre-PhD interest in entrepreneurship and the encouragement of other non-academic industry careers.

  10. Why the early Universe preferred the non-supersymmetric vacuum: part II

    International Nuclear Information System (INIS)

    Abel, Steven A.; Jaeckel, Joerg; Khoze, Valentin V.

    2007-01-01

    It was recently shown that in the context of the ISS models with a metastable supersymmetry breaking vacuum, thermal effects generically drive the Universe to the metastable vacuum even if it began after inflation in the supersymmetry-preserving one. We continue this programme and specifically take into account two new effects. First is the effect of the mass-gap of the gauge degrees of freedom in the confining supersymmetry preserving vacua, and second, is the effect of the back reaction of the MSSM sector on the SUSY breaking ISS sector. It is shown that, even though the mass-gap is parametrically smaller than the (φ), (φ-tilde) vevs, it drastically reduces the temperature required for the Universe to be driven to the metastable vacuum: essentially any temperature larger than the supersymmetry breaking scale μ is sufficient. On the other hand we also find that any reasonable transmission of SUSY breaking to the MSSM sector has no effect on the vacuum transitions to, and the stability of the SUSY breaking vacuum. We conclude that for these models the early Universe does end up in the SUSY breaking vacuum

  11. Integrated Specialized Early-Course Psychosis Treatment Services - University Psychiatric Hospital Vrapce Model.

    Science.gov (United States)

    Ostojić, DraŽenka; Čulo, Ilaria; Silić, Ante; Kos, Suzana; Savić, Aleksandar

    2018-06-01

    First episode of psychosis presents a critical period in terms of numerous associated risks, but also possibilities for effective therapeutic interventions. There is a continued focus on early interventions in prodromal states and early course of frank psychosis, aimed at ensuring faster remission, reducing relapses, achieving better long-term functioning, and preventing adverse outcomes linked to untreated psychosis and chronic psychotic disorders. A number of different specialized treatment models and services exist trying to close knowledge gaps and provide clinical interventions to first-episode psychosis (FEP) patients, but there is still no generally accepted standard of care informing our every-day practice. FEP and early-course psychosis specialized treatment model developed in 2004 in University Psychiatric Hospital Vrapce rests on integration of care across different organization units and clinical presentation acuity levels and patient needs (intensive care, FEP inpatient unit, FEP outpatient services including day hospital). Such integration of FEP services allows for flexible entry point on multiple levels, earlier structuring of therapeutic alliance for those requiring inpatient care, reduction of risks associated with FEP, quicker formation of long-term treatment plans, reduction of delay in accessing specialized services, and a more coordinated diagnostic process and recruitment of FEP patient population. Detailed evaluations of outcomes and comparisons with different treatment models are necessary in order to assess strengths and weaknesses of each specific model and inform modifications to current practice models.

  12. A Determination of the Intergalactic Redshift Dependent UV-Optical-NIR Photon Density Using Deep Galaxy Survey Data and the Gamma-ray Opacity of the Universe

    Science.gov (United States)

    Stecker, Floyd W.; Malkan, Matthew A.; Scully, Sean T.

    2012-01-01

    We calculate the intensity and photon spectrum of the intergalactic background light (IBL) as a function of redshift using an approach based on observational data obtained in many different wavelength bands from local to deep galaxy surveys. This allows us to obtain an empirical determination of the IBL and to quantify its observationally based uncertainties. Using our results on the IBL, we then place 68% confidence upper and lower limits on the opacity of the universe to gamma-rays, free of the theoretical assumptions that were needed for past calculations. We compare our results with measurements of the extragalactic background light and upper limits obtained from observations made by the Fermi Gamma-ray Space Telescope.

  13. Inhaled /sup 147/Pm and/or total-body gamma radiation: Early mortality and morbidity in rats

    Energy Technology Data Exchange (ETDEWEB)

    Filipy, R.E.; Lauhala, K.E.; McGee, D.R.; Cannon, W.C.; Buschbom, R.L.; Decker, J.R.; Kuffel, E.G.; Park, J.F.; Ragan, H.A.; Yaniv, S.S.; Scott, B.R.

    1989-05-01

    Rats were given doses of /sup 60/Co gamma radiation and/or lung burdens of /sup 147/Pm (in fused aluminosilicate particles) within lethal ranges in an experiment to determine and compare morbidity and mortality responses for the radiation insults within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Acute mortality and morbidity from inhaled promethium were caused primarily by radiation pneumonitis and pulmonary fibrosis that occurred more than 53 days after exposure. Acute mortality and morbidity from total-body gamma irradiation occurred within 30 days of exposure and resulted from the bone-marrow radiation syndrome. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell levels and by reduced body weight gain in animals that survived the acute gamma radiation syndrome. Inhaled promethium caused a loss of body weight and diminished pulmonary function, but its only effect on blood cell levels was lymphocytopenia. Combined gamma irradiation and promethium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Promethium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the later effect of promethium lung burdens. 70 refs., 68 figs., 21 tabs.

  14. Superweakly interacting massive particle dark matter signals from the early Universe

    International Nuclear Information System (INIS)

    Feng, Jonathan L.; Rajaraman, Arvind; Takayama, Fumihiro

    2003-01-01

    Cold dark matter may be made of superweakly interacting massive particles, super-WIMP's, that naturally inherit the desired relic density from late decays of metastable WIMP's. Well-motivated examples are weak-scale gravitinos in supergravity and Kaluza-Klein gravitons from extra dimensions. These particles are impossible to detect in all dark matter experiments. We find, however, that super-WIMP dark matter may be discovered through cosmological signatures from the early Universe. In particular, super-WIMP dark matter has observable consequences for big bang nucleosynthesis and the cosmic microwave background (CMB), and may explain the observed underabundance of 7 Li without upsetting the concordance between deuterium and CMB baryometers. We discuss the implications for future probes of CMB blackbody distortions and collider searches for new particles. In the course of this study, we also present a model-independent analysis of entropy production from late-decaying particles in light of Wilkinson microwave anisotropy probe data

  15. On the origin of Hawking mini black-holes and the cold early universe

    Science.gov (United States)

    Canuto, V.

    1978-01-01

    A simple argument is outlined leading to the result that the mass of mini black holes exploding today is 10 to the 15th power g. A mathematical model is discussed which indicates that the equation of state is greatly softened in the high-density regime and a phase transition may exist, such that any length (particularly very small sizes) will grow with time irrespective of its relation to the size of the particle horizon. It is shown that the effect of spin-2 mesons with respect to the equation of state is to soften the pressure and make it negative. An analytical expression is given for the probability that any particular region in a hot early universe will evolve into a black hole.

  16. Primordial black holes from scalar field evolution in the early universe

    Science.gov (United States)

    Cotner, Eric; Kusenko, Alexander

    2017-11-01

    Scalar condensates with large expectation values can form in the early universe, for example, in theories with supersymmetry. The condensate can undergo fragmentation into Q-balls before decaying. If the Q-balls dominate the energy density for some period of time, statistical fluctuations in their number density can lead to formation of primordial black holes (PBH). In the case of supersymmetry the mass range is limited from above by 1 023 g . For a general charged scalar field, this robust mechanism can generate black holes over a much broader mass range, including the black holes with masses of 1-100 solar masses, which is relevant for LIGO observations of gravitational waves. Topological defects can lead to formation of PBH in a similar fashion.

  17. Violation of CPT invariance in the early universe and leptogenesis/baryogenesis

    CERN Document Server

    Mavromatos, Nick E

    2013-01-01

    In this talk, I review some plausible scenarios entailing violation of CPT symmetry in the early Universe, due to space-time backgrounds which do not respect some of the assumptions for the validity of the CPT theorem (here considered will be Lorentz invariance and/or Unitarity). The key point in all these models is that the background induces different populations of fermions as compared to antifermions, and hence CPT Violation (CPTV), already in thermal equilibrium. Such populations may freeze out at various conditions depending on the details of the underlying microscopic model, thereby leading to leptogenesis and baryogenesis. Among the considered scenarios is a stringy one, in which the CPTV is associated with a cosmological background with torsion provided by the Kalb-Ramond antisymmetric tensor field (axion) of the string gravitational multiplet. We also discuss briefly (Lorentz Violating) CPTV models that go beyond the local effective lagrangian framework, such as a stochastic Finsler metric and D-par...

  18. Massive boson-fermion degeneracy and the early structure of the universe

    International Nuclear Information System (INIS)

    Kounnas, C.

    2008-01-01

    The existence of a new kind of massive boson-fermion symmetry is shown explicitly in the framework of the heterotic, type II and type II orientifold superstring theories. The target space-time is two-dimensional. Higher dimensional models are defined via large marginal deformations of J anti J-type. The spectrum of the initial undeformed two dimensional vacuum consists of massless boson degrees of freedom, while all massive boson and fermion degrees of freedom exhibit a new Massive Spectrum Degeneracy Symmetry (MSDS). This precise property, distinguishes the MSDS theories from the well known supersymmetric SUSY-theories. Some proposals are stated in the framework of these theories concerning the structure of: (i) The Early Non-singular Phase of the Universe, (ii) The two dimensional boundary theory of AdS 3 Black-Holes, (iii) Plausible applications of the MSDS theories in particle physics, alternative to SUSY. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  19. Exploring the dusty star-formation in the early Universe using intensity mapping

    Science.gov (United States)

    Lagache, Guilaine

    2018-05-01

    In the last decade, it has become clear that the dust-enshrouded star formation contributes significantly to early galaxy evolution. Detection of dust is therefore essential in determining the properties of galaxies in the high-redshift universe. This requires observations at the (sub-)millimeter wavelengths. Unfortunately, sensitivity and background confusion of single dish observations on the one hand, and mapping efficiency of interferometers on the other hand, pose unique challenges to observers. One promising route to overcome these difficulties is intensity mapping of fluctuations which exploits the confusion-limited regime and measures the collective light emission from all sources, including unresolved faint galaxies. We discuss in this contribution how 2D and 3D intensity mapping can measure the dusty star formation at high redshift, through the Cosmic Infrared Background (2D) and [CII] fine structure transition (3D) anisotropies.

  20. Chemical Evolution and the Formation of Dwarf Galaxies in the Early Universe

    Science.gov (United States)

    Cote, Benoit; JINA-CEE, NuGrid, ChETEC

    2018-06-01

    Stellar abundances in local dwarf galaxies offer a unique window into the nature and nucleosynthesis of the first stars. They also contain clues regarding how galaxies formed and assembled in the early stages of the universe. In this talk, I will present our effort to connect nuclear astrophysics with the field of galaxy formation in order to define what can be learned about galaxy evolution using stellar abundances. In particular, I will describe the current state of our numerical chemical evolution pipeline which accounts for the mass assembly history of galaxies, present how we use high-redshift cosmological hydrodynamic simulations to calibrate our models and to learn about the formation of dwarf galaxies, and address the challenge of identifying the dominant r-process site(s) using stellar abundances.

  1. About the role of Higgs boson in the evolution of the early universe

    International Nuclear Information System (INIS)

    Jegerlehner, Fred

    2014-06-01

    After the discovery of the Higgs particle the most relevant structures of the SM have been verified and for the first time we know all parameters of the SM within remarkable accuracy. Together with recent calculations of the SM renormalization group coefficients up to three loops we can safely extrapolate running couplings high up in energy. Assuming that the SM is a low energy effective theory of a cutoff theory residing at the Planck scale, we are able to calculate the effective bare parameters of the underlying cutoff system. It turns out that the effective bare mass term changes sign not far below the Planck scale, which means that in the early universe the SM was in the symmetric phase. The sign-flip, which is a result of a conspiracy between the SM couplings and their screening/antiscreening behavior, triggers the Higgs mechanism. Above the Higgs phase transition the bare mass term in the Higgs potential must have had a large positive value, enhanced by the quadratic divergence of the bare Higgs mass. Likewise the quartically enhanced positive vacuum energy density is present in the symmetric phase. The Higgs system thus provides the large dark energy density in the early universe, which triggers slow-roll inflation, i.e. the SM Higgs is the inflaton scalar field. Reheating is dominated by the decay of the heavy Higgses into (in the symmetric phase) massless top/anti-top quark pairs. The new scenario possibly could explain the baryon-asymmetry essentially in terms of SM physics.

  2. A tale of two timescales: Mixing, mass generation, and phase transitions in the early universe

    Science.gov (United States)

    Dienes, Keith R.; Kost, Jeff; Thomas, Brooks

    2016-02-01

    Light scalar fields such as axions and string moduli can play an important role in early-universe cosmology. However, many factors can significantly impact their late-time cosmological abundances. For example, in cases where the potentials for these fields are generated dynamically—such as during cosmological mass-generating phase transitions—the duration of the time interval required for these potentials to fully develop can have significant repercussions. Likewise, in scenarios with multiple scalars, mixing amongst the fields can also give rise to an effective timescale that modifies the resulting late-time abundances. Previous studies have focused on the effects of either the first or the second timescale in isolation. In this paper, by contrast, we examine the new features that arise from the interplay between these two timescales when both mixing and time-dependent phase transitions are introduced together. First, we find that the effects of these timescales can conspire to alter not only the total late-time abundance of the system—often by many orders of magnitude—but also its distribution across the different fields. Second, we find that these effects can produce large parametric resonances which render the energy densities of the fields highly sensitive to the degree of mixing as well as the duration of the time interval over which the phase transition unfolds. Finally, we find that these effects can even give rise to a "reoverdamping" phenomenon which causes the total energy density of the system to behave in novel ways that differ from those exhibited by pure dark matter or vacuum energy. All of these features therefore give rise to new possibilities for early-universe phenomenology and cosmological evolution. They also highlight the importance of taking into account the time dependence associated with phase transitions in cosmological settings.

  3. A clinical trial on the treatment of burns in children at the University Teaching Hospital using amniotic membrane sterilized by gamma radiation (July to December 1994)

    International Nuclear Information System (INIS)

    Katebe, K.R.C.

    1995-01-01

    About six hundred patients are admitted to the University Teaching Hospital every year. Most of the burns are from water and fire with a high mortality rate in children. This study was centred on the feasibility of using amniotic membrane for wound dressing. The method of Gamma radiation was employed to sterilize this biological tissue before utilising it on patients. The results of the study show more superior healing rate compared with other methods. There was lack of hypersensitivity reactions and reduced wound infection and good quality wound healing. The method is easy to use and has been accepted by the patients and nursing staff. (n.m.). 20 refs., tabs., 6 graphs

  4. Black hole growth in the early Universe is self-regulated and largely hidden from view.

    Science.gov (United States)

    Treister, Ezequiel; Schawinski, Kevin; Volonteri, Marta; Natarajan, Priyamvada; Gawiser, Eric

    2011-06-15

    The formation of the first massive objects in the infant Universe remains impossible to observe directly and yet it sets the stage for the subsequent evolution of galaxies. Although some black holes with masses more than 10(9) times that of the Sun have been detected in luminous quasars less than one billion years after the Big Bang, these individual extreme objects have limited utility in constraining the channels of formation of the earliest black holes; this is because the initial conditions of black hole seed properties are quickly erased during the growth process. Here we report a measurement of the amount of black hole growth in galaxies at redshift z = 6-8 (0.95-0.7 billion years after the Big Bang), based on optimally stacked, archival X-ray observations. Our results imply that black holes grow in tandem with their host galaxies throughout cosmic history, starting from the earliest times. We find that most copiously accreting black holes at these epochs are buried in significant amounts of gas and dust that absorb most radiation except for the highest-energy X-rays. This suggests that black holes grew significantly more during these early bursts than was previously thought, but because of the obscuration of their ultraviolet emission they did not contribute to the re-ionization of the Universe.

  5. CP violation in bilinear R-parity violation and its consequences for the early universe

    Energy Technology Data Exchange (ETDEWEB)

    Cheriguene, Asma; Porod, Werner [Wuerzburg Univ. (Germany). Inst. fuer Theoretische Physik und Astrophysik; Liebler, Stefan [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2014-06-15

    Supersymmetric models with bilinear R-parity violation (BRpV) provide a framework for neutrino masses and mixing angles to explain neutrino oscillation data. We consider CP violation within the new physical phases in BRpV and discuss their effect on the generation of neutrino masses and the decays of the lightest supersymmetric particle (LSP), being a light neutralino with mass ∝100 GeV, at next-to-leading order. The decays affect the lepton and via sphaleron transitions the baryon asymmetry in the early universe. For a rather light LSP, asymmetries generated before the electroweak phase transition via e.g. the Affleck-Dine mechanism are reduced up to two orders of magnitude, but are still present. On the other hand, the decays of a light LSP themselves can account for the generation of a lepton and baryon asymmetry, the latter in accordance to the observation in our universe, since the smallness of the BRpV parameters allows for an out-of-equilibrium decay and sufficiently large CP violation is possible consistent with experimental bounds from the non-observation of electric dipole-moments.

  6. The politics of universalism. Strategic uses of human rights discourses in early modernity

    Directory of Open Access Journals (Sweden)

    Karen-Margrethe Simonsen

    2013-11-01

    Full Text Available This article investigates the political function of human rights in 16th-century Spain just after the conquest of America. It claims that the study of this period of early globalization is relevant for an understanding of the function of human rights discourses today, at the “end” of globalization. Historically speaking, human rights are closely connected with globalization, but at the same time, they raise the question about the foundation of globalization: is there a universal community or only economic and political power-relations? This article argues that the political use of human rights discourses is split down the middle: it serves both as a critique of power and as an extension of power, and the disclosure of this split helps us understand the inner politics of human rights. The article discusses the trial in Valladolid in 1550 when the rights of the barbarian Indians of America were put on trial. It focuses mainly on the arguments made by Bartolomé de las Casas and on the reasons why the King allowed las Casas’ fierce critique of the conquest to be published in a period of otherwise severe censorship. This article is inspired by Etienne Balibar's idea of “politics of universalism,” “political autonomy,” and “equaliberty.”.

  7. Entropy Growth in the Early Universe and Confirmation of Initial Big Bang Conditions

    Science.gov (United States)

    Beckwith, Andrew

    2009-09-01

    This paper shows how increased entropy values from an initially low big bang level can be measured experimentally by counting relic gravitons. Furthermore the physical mechanism of this entropy increase is explained via analogies with early-universe phase transitions. The role of Jack Ng's (2007, 2008a, 2008b) revised infinite quantum statistics in the physics of gravitational wave detection is acknowledged. Ng's infinite quantum statistics can be used to show that ΔS~ΔNgravitons is a startmg point to the increasing net universe cosmological entropy. Finally, in a nod to similarities AS ZPE analysis, it is important to note that the resulting ΔS~ΔNgravitons ≠ 1088, that in fact it is much lower, allowing for evaluating initial graviton production as an emergent field phenomena, which may be similar to how ZPE states can be used to extract energy from a vacuum if entropy is not maximized. The rapid increase in entropy so alluded to without near sudden increases to 1088 may be enough to allow successful modeling of relic graviton production for entropy in a manner similar to ZPE energy extraction from a vacuum state.

  8. Home and Community Language Proficiency in Spanish-English Early Bilingual University Students.

    Science.gov (United States)

    Schmidtke, Jens

    2017-10-17

    This study assessed home and community language proficiency in Spanish-English bilingual university students to investigate whether the vocabulary gap reported in studies of bilingual children persists into adulthood. Sixty-five early bilinguals (mean age = 21 years) were assessed in English and Spanish vocabulary and verbal reasoning ability using subtests of the Woodcock-Muñoz Language Survey-Revised (Schrank & Woodcock, 2009). Their English scores were compared to 74 monolinguals matched in age and level of education. Participants also completed a background questionnaire. Bilinguals scored below the monolingual control group on both subtests, and the difference was larger for vocabulary compared to verbal reasoning. However, bilinguals were close to the population mean for verbal reasoning. Spanish scores were on average lower than English scores, but participants differed widely in their degree of balance. Participants with an earlier age of acquisition of English and more current exposure to English tended to be more dominant in English. Vocabulary tests in the home or community language may underestimate bilingual university students' true verbal ability and should be interpreted with caution in high-stakes situations. Verbal reasoning ability may be more indicative of a bilingual's verbal ability.

  9. Gravity, black holes and the very early Universe an introduction to general relativity and cosmology

    CERN Document Server

    Chow, Tai L

    2008-01-01

    In the early 1900s, Albert Einstein formulated two theories that would forever change the landscape of physics: the Special Theory of Relativity and the General Theory of Relativity. By 1925, quantum mechanics had been born out of the dissection of these two theories, and shortly after that, relativistic quantum field theory. We now had in place some important ties between the laws of physics and the types of particle interactions the new physics was uncovering. Gravity is one of the four types of forces that are found throughout the universe. In fact, although it is a relatively weak force, it operates at huge distances, and so must be accounted for in any cosmological system. Unfortunately, gravity continues to defy our neat categorization of how all the forces in nature work together. Professor Tai Chow, from the California State University at Stanislaus in Turlock, lays out for us the basic ideas of Einstein, including his law of gravitation, explains the physics behind black holes, and weaves into this a...

  10. Spacetime deformation effect on the early universe and the PTOLEMY experiment

    Directory of Open Access Journals (Sweden)

    Raul Horvat

    2017-09-01

    Full Text Available Using a fully-fledged formulation of gauge field theory deformed by the spacetime noncommutativity, we study its impact on relic neutrino direct detection, as proposed recently by the PTOLEMY experiment. The noncommutative background tends to influence the propagating neutrinos by providing them with a tree-level vector-like coupling to photons, enabling thus otherwise sterile right-handed (RH neutrinos to be thermally produced in the early universe. Such a new component in the universe's background radiation has been switched today to the almost fully active sea of non-relativistic neutrinos, exerting consequently some impact on the capture on tritium at PTOLEMY. The peculiarities of our nonperturbative approach tend to reflect in the cosmology as well, upon the appearances of the coupling temperature, above which RH neutrinos stay permanently decoupled from thermal environment. This entails the maximal scale of noncommutativity as well, being of order of 10−4MPl, above which there is no impact whatsoever on the capture rates at PTOLEMY. The latter represents an exceptional upper bound on the scale of noncommutativity coming from phenomenology.

  11. Correlation Of Terrestrial gamma flashes, Electric fields, and Lightning strikes (COTEL) in thunderstorms using networked balloon payloads developed by university and community college students

    Science.gov (United States)

    Landry, B. J.; Blair, D.; Causey, J.; Collins, J.; Davis, A.; Fernandez-Kim, V.; Kennedy, J.; Pate, N.; Kearney, C.; Schayer, C.; Turk, E.; Cherry, M. L.; Fava, C.; Granger, D.; Stewart, M.; Guzik, T. G.

    2017-12-01

    High energy gamma ray flashes from terrestrial sources have been observed by satellites for decades, but the actual mechanism, assumed to be thunderstorm lightning, has yet to be fully characterized. The goal of COTEL, funded by NASA through the University Student Instrument Project (USIP) program, is to correlate in time TGF events, lightning strikes, and electric fields inside of thunderstorms. This will be accomplished using a small network of balloon-borne payloads suspended in and around thunderstorm environments. The payloads will detect and timestamp gamma radiation bursts, lightning strikes, and the intensity of localized electric fields. While in flight, data collected by the payloads will be transmitted to a ground station in real-time and will be analyzed post-flight to investigate potential correlations between lightning, TGFs, and electric fields. The COTEL student team is in its second year of effort having spent the first year developing the basic balloon payloads and ground tracking system. Currently the team is focusing on prototype electric field and gamma radiation detectors. Testing and development of these systems will continue into 2018, and flight operations will take place during the spring 2018 Louisiana thunderstorm season. The presentation, led by undergraduate Physics student Brad Landry, will cover the student team effort in developing the COTEL system, an overview of the system architecture, balloon flight tests conducted to date, preliminary results from prototype detectors, lessons learned for student-led science projects, and future plans.

  12. Exploring the Structure and Evolution of the Universe: Multi-Band Profiles of the Known Gamma-Ray Pulsars

    Science.gov (United States)

    1998-01-01

    As summarized in this pamphlet, some of the far-reaching underlying issues to be addressed include: What is the origin of the universe and its destiny; Why is the universe lumpy; How did the known structures of the universe evolve; How do galaxies evolve; How do massive black holes grow; How did the elemental composition of the universe evolve; What is the structure and behavior of matter in the extreme; and Is Einstein's general relativity theory right.

  13. Production of light elements by cascades from energetic antiprotons in the early Universe and problem of nuclear cosmoarcheology

    International Nuclear Information System (INIS)

    Levitan, Yu.L.; Sobol', I.M.; Khlopov, M.Yu.; Chechetkin, V.M.

    1988-01-01

    The mathematical model of the process of light-element (D and 3 He) production due to disintegration of 4 He nuclei, induced by nonequilibrium processes of production of energetic antiprotons in the early Universe is suggested. Numerical calculations show that formation of the nucleon cascade induced by antiproton slowing down increases the D and 3 He yield due to the growth of probability of disintegration of several 4 He nuclei by a single antiproton and due to disintegration of such nuclei by cascade protons. Restraints on the concentration of possible sources of energetic antiprotons in the early Universe are strengthened respectively

  14. Phase Transitions in the Early Universe: The Cosmology of Non-Minimal Scalar Sectors

    Science.gov (United States)

    Kost, Jeffrey D.

    Light scalar fields such as axions and string moduli can play an important role in early-universe cosmology. However, many factors can significantly impact their late-time cosmological abundances. For example, in cases where the potentials for these fields are generated dynamically--such as during cosmological mass-generating phase transitions--the duration of the time interval required for these potentials to fully develop can have significant repercussions. Likewise, in scenarios with multiple scalars, mixing amongst the fields can also give rise to an effective timescale that modifies the resulting late-time abundances. Previous studies have focused on the effects of either the first or the second timescale in isolation. In this thesis, by contrast, we examine the new features that arise from the interplay between these two timescales when both mixing and time-dependent phase transitions are introduced together. First, we find that the effects of these timescales can conspire to alter not only the total late-time abundance of the system--often by many orders of magnitude--but also its distribution across the different fields. Second, we find that these effects can produce large parametric resonances which render the energy densities of the fields highly sensitive to the degree of mixing as well as the duration of the time interval over which the phase transition unfolds. Finally, we find that these effects can even give rise to a "re-overdamping" phenomenon which causes the total energy density of the system to behave in novel ways that differ from those exhibited by pure dark matter or vacuum energy. All of these features therefore give rise to new possibilities for early-universe phenomenology and cosmological evolution. They also highlight the importance of taking into account the time dependence associated with phase transitions in cosmological settings. In the second part of this thesis, we proceed to study the early-universe cosmology of a Kaluza-Klein (KK

  15. Spider: Probing the Early Universe with a Large-Scale CMB Polarization Survey

    Science.gov (United States)

    Jones, William

    The standard dark-matter and dark-energy dominated cosmological model (LCDM) has proven to be remarkably successful in describing the current state and past evolution of the Universe. However, there remain significant uncertainties regarding the physical mechanisms that established the initial conditions upon which the LCDM predictions rely. Theories of cosmic genesis - the extremely high energy mechanisms that established these conditions - should be expected to provide a natural description of the nearly flat geometry of the Universe, the existence of super-horizon density correlations, and the adiabatic, Gaussian and nearly scale-invariant nature of the observed primordial density perturbations. The primary objective of Spider is to subject models of the early Universe to observational test, probing fundamental physics at energy scales far beyond the reach of terrestrial particle accelerators. The main scientific result will be to characterize, or place stringent upper limits on the level of the odd-parity polarization of the CMB. In the context of the inflationary paradigm, Spider will confirm or exclude the predictions of the simplest single-field inflationary models near the Lyth bound, characterized by tensor to scalar ratios r 0.03. While viable alternatives to the inflationary paradigm are an active and important area of investigation, including string cosmologies and cyclic models, early Universe models described by inflationary periods are now widely accepted as the underlying cause behind much of what we observe in cosmology today. Nevertheless, we know very little about the mechanism that would drive inflation or the energy scale at which it occurred, and the paradigm faces significant questions about the viability of the framework as a scientific theory. Fortunately, inflationary paradigms and alternative theories offer distinct predictions regarding the statistical properties of the Cosmic Microwave Background radiation. Spider will use measurements

  16. THERMAL EMISSION IN THE EARLY X-RAY AFTERGLOWS OF GAMMA-RAY BURSTS: FOLLOWING THE PROMPT PHASE TO LATE TIMES

    Energy Technology Data Exchange (ETDEWEB)

    Friis, Mette [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik (Iceland); Watson, Darach, E-mail: mef4@hi.is, E-mail: darach@dark-cosmology.dk [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark)

    2013-07-01

    Thermal radiation, peaking in soft X-rays, has now been detected in a handful of gamma-ray burst (GRB) afterglows and has to date been interpreted as shock break-out of the GRB's progenitor star. We present a search for thermal emission in the early X-ray afterglows of a sample of Swift bursts selected by their brightness in X-rays at early times. We identify a clear thermal component in eight GRBs and track the evolution. We show that at least some of the emission must come from highly relativistic material since two show an apparent super-luminal expansion of the thermal component. Furthermore, we determine very large luminosities and high temperatures for many of the components-too high to originate in a supernova shock break-out. Instead, we suggest that the component may be modeled as late photospheric emission from the jet, linking it to the apparently thermal component observed in the prompt emission of some GRBs at gamma-ray and hard X-ray energies. By comparing the parameters from the prompt emission and the early afterglow emission, we find that the results are compatible with the interpretation that we are observing the prompt quasi-thermal emission component in soft X-rays at a later point in its evolution.

  17. Replication RCT of Early Universal Prevention Effects on Young Adult Substance Misuse

    Science.gov (United States)

    Spoth, Richard; Trudeau, Linda; Redmond, Cleve; Shin, Chungyeol

    2014-01-01

    Objective For many substances, more frequent and problematic use occurs in young adulthood; these types of use are predicted by the timing of initiation during adolescence. We replicated and extended an earlier study examining whether delayed substance initiation during adolescence, resulting from universal preventive interventions implemented in middle school, reduces problematic use in young adulthood. Method Participants were middle school students from 36 Iowa schools randomly assigned to the Strengthening Families Program plus Life Skills Training (SFP 10–14 + LST), LST-only, or a control condition. Self-report questionnaires were collected at 11 time points, including four during young adulthood. The intercept (average level) and rate of change (slope) in young adult frequency measures (drunkenness, alcohol-related problems, cigarettes, and illicit drugs) across ages 19–22 were modeled as outcomes influenced by growth factors describing substance initiation during adolescence. Analyses entailed testing a two-step hierarchical latent growth curve model; models included the effects of baseline risk, intervention condition assignment, and their interaction. Results Analyses showed significant indirect intervention effects on the average levels of all young adult outcomes, through effects on adolescent substance initiation growth factors, along with intervention by risk interaction effects favoring the higher-risk subsample. Additional direct effects on young adult use were observed in some cases. Relative reduction rates were larger for the higher-risk subsample at age 22, ranging from 5.8% to 36.4% on outcomes showing significant intervention effects. Conclusions Universal preventive interventions implemented during early adolescence have the potential to decrease the rates of substance use and associated problems, into young adulthood. PMID:24821095

  18. Energy Feedback from X-ray Binaries in the Early Universe

    Science.gov (United States)

    Fragos, T.; Lehmer, B..; Naoz, S.; Zezas, A.; Basu-Zych, A.

    2013-01-01

    X-ray photons, because of their long mean-free paths, can easily escape the galactic environments where they are produced, and interact at long distances with the intergalactic medium, potentially having a significant contribution to the heating and reionization of the early universe. The two most important sources of X-ray photons in the universe are active galactic nuclei (AGNs) and X-ray binaries (XRBs). In this Letter we use results from detailed, large scale population synthesis simulations to study the energy feedback of XRBs, from the first galaxies (z (redshift) approximately equal to 20) until today.We estimate that X-ray emission from XRBs dominates over AGN at z (redshift) greater than or approximately equal to 6-8. The shape of the spectral energy distribution of the emission from XRBs shows little change with redshift, in contrast to its normalization which evolves by approximately 4 orders of magnitude, primarily due to the evolution of the cosmic star-formation rate. However, the metallicity and the mean stellar age of a given XRB population affect significantly its X-ray output. Specifically, the X-ray luminosity from high-mass XRBs per unit of star-formation rate varies an order of magnitude going from solar metallicity to less than 10% solar, and the X-ray luminosity from low-mass XRBs per unit of stellar mass peaks at an age of approximately 300 Myr (million years) and then decreases gradually at later times, showing little variation for mean stellar ages 3 Gyr (Giga years, or billion years). Finally, we provide analytical and tabulated prescriptions for the energy output of XRBs, that can be directly incorporated in cosmological simulations.

  19. Domain Walls and Matter-Antimatter Domains in the Early Universe

    Directory of Open Access Journals (Sweden)

    Dolgov A.D.

    2017-01-01

    Full Text Available We suggest a scenario of spontaneous (or dynamical C and CP violation according to which it is possible to generate domains of matter and antimatter separated by cosmologically large distances. Such C(CP violation existed only in the early universe and later it disappeared with the only trace of generated matter and antimatter domains. So this scenario does not suffer from the problem of domain walls. According to this scenario the width of the domain wall should grow exponentially to prevent annihilation at the domain boundaries. Though there is a classical result obtained by Basu and Vilenkin that the width of the wall tends to the one of the stationary solution (constant physical width. That is why we considered thick domain walls in a de Sitter universe following paper by Basu and Vilenkin. However, we were interested not only in stationary solutions found therein, but also investigated the general case of domain wall evolution with time. When the wall thickness parameter, δ0 , is smaller than H−1/2 where H is the Hubble parameter in de Sitter space-time, then the stationary solutions exist, and initial field configurations tend with time to the stationary ones. However, there are no stationary solutions for δ0>H−1/2 We have calculated numerically the rate of the wall expansion in this case and have found that the width of the wall grows exponentially fast for δ0≫H−1 An explanation for the critical value δ0c=H−1/2 is also proposed.

  20. Spontaneous B-L breaking as the origin of the hot early universe

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, W.; Domcke, V.; Schmitz, K.

    2012-03-15

    The decay of a false vacuum of unbroken B-L symmetry is an intriguing and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase yields hybrid inflation, ending in tachyonic preheating. The dynamics of the B - L breaking Higgs field and thermal processes produce an abundance of heavy neutrinos whose decays generate entropy, baryon asymmetry and gravitino dark matter. We study the phase transition for the full supersymmetric Abelian Higgs model. For the subsequent reheating process we give a detailed time-resolved description of all particle abundances. The competition of cosmic expansion and entropy production leads to an intermediate period of constant 'reheating' temperature, during which baryon asymmetry and dark matter are produced. Consistency of hybrid inflation, leptogenesis and gravitino dark matter implies relations between neutrino parameters and superparticle masses, in particular a lower bound on the gravitino mass of 10 GeV.

  1. Using Electronic Portfolio to Promote Professional Learning Community for Pre-Service Early Childhood Teachers at Alquds University

    Science.gov (United States)

    Khales, Buad

    2016-01-01

    The present study aims to explore whether the electronic portfolio can influence pre-service teachers' education and to examine how professional learning communities develop through electronic portfolios. To achieve this, twenty-four student-teachers taking a course in early childhood education at Al-Quds University participated in a study to…

  2. "Swim or Sink": State of Induction in the Deployment of Early Career Academics into Teaching at Makerere University

    Science.gov (United States)

    Ssempebwa, Jude; Teferra, Damtew; Bakkabulindi, Fred Edward K.

    2016-01-01

    Conducted as part of a multi-country study of the teaching-related experiences and expectations of early career academics (ECAs) in Africa, this study investigated the major influences on the teaching practice of ECAs at Makerere University; the mechanisms by which these academics learn to teach; the teaching-related challenges they experience;…

  3. EDGE: explorer of diffuse emission and gamma-ray burst explosions

    NARCIS (Netherlands)

    den Herder, J.W.; Piro, L.; Ohashi, T.; Amati, L.; Atteia, J.; Barthelmy, S.D.; Barbera, M.; Barret, D.; Basso, S.; de Boer, M.; Borgani, S.; Boyarskiy, O.; Branchini, E.; Branduardi-Raymont, G.; Briggs, M.; Brunetti, G.; Budtz-Jorgensenf, C.; Burrows, D.N.; Campana, S.; Caroli, E.; Chincarini, G.; Christensen, F.; Cocchi, M.; Comastri, A.; Corsi, A.; Cotroneo, V.; Conconi, P.; Colasanti, L.; Cusamano, G.; Rosa, A.; Del Santo, M.; Ettori, S.; Ezoe, Y.; Ferrari, L.; Feroci, M.; Finger, M.; Fishman, G.; Fujimoto, R.; Galeazzi, M.; Galli, A.; Gatti, F.; Gehrels, N.; Gendre, B.; Ghirlanda, G.; Ghisellini, G.; Giommi, P.; Girardi, M.; Guzzo, L.; Haardt, F.; Hepburn, I.; Hermsen, W.; Hoevers, H.; Holland, A.; in 't Zand, J.J.M.; Ishisaki, Y.; Kawahara, H.; Kawai, N.; Kaastra, J.; Kippen, M.; de Korte, P.A.J.; Kouveliotou, C.; Kusenko, A.; Labanti, C.; Lieu, R.; Macculi, C.; Makishima, K.; Matt, G.; Mazotta, P.; McCammon, D.; Méndez, M.; Mineo, T.; Mitchell, S.; Mitsuda, K.; Molendi, S.; Moscardini, L.; Mushotzky, R.; Natalucci, L.; Nicastro, F.; O'Brien, P.; Osborne, J.; Paerels, F.; Page, M.; Paltani, S.; Pareschi, G.; Perinati, E.; Perola, C.; Ponman, T.; Rasmussen, A.; Roncarelli, M.; Rosati, P.; Ruchayskiy, O.; Quadrini, E.; Sakurai, I.; Salvaterra, R.; Sasaki, S.; Wijers, R.; et al., [Unknown

    2007-01-01

    How structures of various scales formed and evolved from the early Universe up to present time is a fundamental question of astrophysics. EDGE will trace the cosmic history of the baryons from the early generations of massive stars by Gamma-Ray Burst (GRB) explosions, through the period of galaxy

  4. Treatment of trochanteric fractures with the gamma3 nail - methodology and early results of a prospective consecutive monitored clinical case series.

    Science.gov (United States)

    A C, Unger; E, Wilde; B, Kienast; C, Jürgens; A P, Schulz

    2014-01-01

    There is only sparse data on clinical results and complications of the third-generation Gamma nailing system (Gamma3, Stryker). Therefore, we started a large multi-centre case series in 2008. The aim of this paper is to present the study design and early results of a single arm of a prospective, consecutive, monitored, post-market follow-up evaluation of Gamma3 nails. From September 2009 to January 2012, 154 consecutive patients with an average age of 80 ± 1.43 years (50-99 years) and a trochanteric femoral fracture were included in the local arm of the trial. All patients that fulfilled the inclusion criteria were treated with a Gamma3 nail. Preoperative variables included age, gender, fracture classification, walking ability (Merle d'Aubigné score), daily activity level (retrospective Zuckerman score), ASA rating of operative risk, waiting time for operation, use of walker or crutches and body mass index (BMI). Skin-to-skin time, fluoroscopy time, blood loss, intraoperative complications and device information were recorded for each patient. Follow-up postoperative assessment was undertaken at 4, 12 and 24 months. Hip range of motion, pain around the hip and the tight, walking ability (Merle d'Aubigné score, Sahlgrenska mobility score) and management of daily life (Zuckerman score) were used to evaluate the outcome. The descriptive data of age, gender, BMI, ASA classification, fracture type and skin-to-skin time is similar to other studies. Median fluoroscopy time was 62 seconds (range: 4-225 seconds) and significantly shorter in closed reductions. No intraoperative implant-related complication was recorded. A cut-out of the leg-screw during assessment period occurred in 2.6% patients (n = 4). At the 12-month assessment two (1.8%) non-unions were identified and two patients (1.8%) had broken the femoral shaft below the 180 mm nail after a fall. Analysis of the scores showed significantly declined mobility and activity in daily life four months after operation

  5. Stress and hazardous alcohol use: associations with early dropout from university.

    Science.gov (United States)

    Andersson, Claes; Johnsson, Kent O; Berglund, Mats; Ojehagen, Agneta

    2009-09-01

    The transition to studying at university is associated with increased levels of both stress and hazardous alcohol use. The aim of this study is to investigate the influence of these factors on first-year dropout from university studies. Two complete cohorts of university freshmen at two homogeneous universities, one in the north and one in the south of Sweden, were asked to participate in an intervention study. Participants responded to a baseline questionnaire including measures of stress and alcohol use. Official university records showing dropout over 12 months were collected. A multivariate analysis established that high stress and admission to the northern university were associated with dropout from university studies, while symptoms of depression and anxiety as well as hazardous drinking were not. There is a need to address the issue of stress associated with the start of university studies. It seems important to offer stress-reducing interventions, specifically aimed at reducing transitional stress, as soon as students start university.

  6. THE CHEMISTRY OF POPULATION III SUPERNOVA EJECTA. I. FORMATION OF MOLECULES IN THE EARLY UNIVERSE

    International Nuclear Information System (INIS)

    Cherchneff, Isabelle; Dwek, Eli

    2009-01-01

    outer mass zone of the ejecta. Finally, we discuss the cosmological implication of molecule formation by Pop III SNe in the early universe.

  7. An Extreme Protocluster of Luminous Dusty Starbursts in the Early Universe

    Science.gov (United States)

    Oteo, I.; Ivison, R. J.; Dunne, L.; Manilla-Robles, A.; Maddox, S.; Lewis, A. J. R.; de Zotti, G.; Bremer, M.; Clements, D. L.; Cooray, A.; Dannerbauer, H.; Eales, S.; Greenslade, J.; Omont, A.; Perez–Fournón, I.; Riechers, D.; Scott, D.; van der Werf, P.; Weiss, A.; Zhang, Z.-Y.

    2018-03-01

    We report the identification of an extreme protocluster of galaxies in the early universe whose core (nicknamed Distant Red Core, DRC, because of its very red color in Herschel SPIRE bands) is formed by at least 10 dusty star-forming galaxies (DSFGs), spectroscopically confirmed to lie at {z}spec}=4.002 via detection of [C I](1–0), 12CO(6–5), 12CO(4–3), 12CO(2–1), and {{{H}}}2{{O}}({2}11{--}{2}02) emission lines with ALMA and ATCA. These DSFGs are distributed over a 260 {kpc}× 310 {kpc} region and have a collective obscured star formation rate (SFR) of ∼ 6500 {M}ȯ {yr}}-1, considerably higher than those seen before in any protocluster at z≳ 4. Most of the star formation is taking place in luminous DSFGs since no Lyα emitters are detected in the protocluster core, apart from a Lyα blob located next to one of the DRC components, extending over 60 {kpc}. The total obscured SFR of the protocluster could rise to {SFR}∼ {{14,400}} {M}ȯ {yr}}-1 if all the members of an overdensity of bright DSFGs discovered around DRC in a wide-field Large APEX BOlometer CAmera 870 μm image are part of the same structure. [C I](1–0) emission reveals that DRC has a total molecular gas mass of at least {M}{{{H}}2}∼ 6.6× {10}11 {M}ȯ , and its total halo mass could be as high as ∼ 4.4× {10}13 {M}ȯ , indicating that it is the likely progenitor of a cluster at least as massive as Coma at z = 0.

  8. FAST MAGNETIC FIELD AMPLIFICATION IN THE EARLY UNIVERSE: GROWTH OF COLLISIONLESS PLASMA INSTABILITIES IN TURBULENT MEDIA

    Energy Technology Data Exchange (ETDEWEB)

    Falceta-Gonçalves, D. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Kowal, G. [Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, Rua Arlindo Bettio, 1000, São Paulo, SP 03828-000 (Brazil)

    2015-07-20

    In this work we report on a numerical study of the cosmic magnetic field amplification due to collisionless plasma instabilities. The collisionless magnetohydrodynamic equations derived account for the pressure anisotropy that leads, in specific conditions, to the firehose and mirror instabilities. We study the time evolution of seed fields in turbulence under the influence of such instabilities. An approximate analytical time evolution of the magnetic field is provided. The numerical simulations and the analytical predictions are compared. We found that (i) amplification of the magnetic field was efficient in firehose-unstable turbulent regimes, but not in the mirror-unstable models; (ii) the growth rate of the magnetic energy density is much faster than the turbulent dynamo; and (iii) the efficient amplification occurs at small scales. The analytical prediction for the correlation between the growth timescales and pressure anisotropy is confirmed by the numerical simulations. These results reinforce the idea that pressure anisotropies—driven naturally in a turbulent collisionless medium, e.g., the intergalactic medium, could efficiently amplify the magnetic field in the early universe (post-recombination era), previous to the collapse of the first large-scale gravitational structures. This mechanism, though fast for the small-scale fields (∼kpc scales), is unable to provide relatively strong magnetic fields at large scales. Other mechanisms that were not accounted for here (e.g., collisional turbulence once instabilities are quenched, velocity shear, or gravitationally induced inflows of gas into galaxies and clusters) could operate afterward to build up large-scale coherent field structures in the long time evolution.

  9. HUBBLE'S ULTRAVIOLET VIEWS OF NEARBY GALAXIES YIELD CLUES TO EARLY UNIVERSE

    Science.gov (United States)

    2002-01-01

    , NGC 3310, shows young and old stars evenly distributed. If this were the case with most galaxies, astronomers would be able to recognize faraway galaxies fairly easily. In most galaxies, however, the stars are segregated by age, making classifying the distant ones more difficult. NGC 3310 is 46 million light-years from Earth in the constellation Ursa Major. The image was taken Sept. 12-13, 2000. The middle image is an example of a tiny, youthful spiral galaxy. ESO 418-008 is representative of the myriad of dwarf galaxies astronomers have seen in deep surveys. These galaxies are much smaller than typical ones like our Milky Way. In this galaxy, the population of stars is more strongly segregated by age. The older stars [red] reside in the center; the younger [blue], in the developing spiral arms. These small, young galaxies may be the building blocks of galaxy formation. ESO 418-008 is 56 million light-years from Earth in the southern constellation Fornax. The image was taken Oct. 10, 2000. The picture at right shows a cosmic collision between two galaxies, UGC 06471 and UGC 06472. These collisions occurred frequently in the early universe, producing galaxies of unusual shapes. The Hubble telescope has spied many such galaxies in the deep field surveys. The ultraviolet images of this galaxy merger suggest the presence of large amounts of dust, which were produced by massive stars that formed before or during this dramatic collision. This dust reddens the starlight in many places, just like a dusty atmosphere reddens the sunset. Studying the effects of this nearby collision could help astronomers explain the peculiar shapes seen in some of the distant galaxies. UGC 06471 and UGC 06472 are 145 million light-years from Earth in the constellation Ursa Major. The image was taken July 11, 2000. Photo credits: NASA, Rogier Windhorst (Arizona State University, Tempe, AZ), and the Hubble mid-UV team

  10. Gamma Ray Bursts-Afterglows and Counterparts

    Science.gov (United States)

    Fishman, Gerald J

    1998-01-01

    Several breakthrough discoveries were made last year of x-ray, optical and radio afterglows and counterparts to gamma-ray bursts, and a redshift has been associated with at least one of these. These discoveries were made possible by the fast, accurate gamma-ray burst locations of the BeppoSAX satellite. It is now generally believed that the burst sources are at cosmological distances and that they represent the most powerful explosions in the Universe. These observations also open new possibilities for the study of early star formation, the physics of extreme conditions and perhaps even cosmology. This session will concentrate on recent x-ray, optical and radio afterglow observations of gamma-ray bursts, associated redshift measurements, and counterpart observations. Several review and theory talks will also be presented, along with a summary of the astrophysical implications of the observations. There will be additional poster contributions on observations of gamma-ray burst source locations at wavelengths other than gamma rays. Posters are also solicited that describe new observational capabilities for rapid follow-up observations of gamma-ray bursts.

  11. Cosmological QCD phase transition in steady non-equilibrium dissipative Hořava–Lifshitz early universe

    International Nuclear Information System (INIS)

    Khodadi, M.; Sepangi, H.R.

    2014-01-01

    We study the phase transition from quark–gluon plasma to hadrons in the early universe in the context of non-equilibrium thermodynamics. According to the standard model of cosmology, a phase transition associated with chiral symmetry breaking after the electro-weak transition has occurred when the universe was about 1–10 μs old. We focus attention on such a phase transition in the presence of a viscous relativistic cosmological background fluid in the framework of non-detailed balance Hořava–Lifshitz cosmology within an effective model of QCD. We consider a flat Friedmann–Robertson–Walker universe filled with a non-causal and a causal bulk viscous cosmological fluid respectively and investigate the effects of the running coupling constants of Hořava–Lifshitz gravity, λ, on the evolution of the physical quantities relevant to a description of the early universe, namely, the temperature T, scale factor a, deceleration parameter q and dimensionless ratio of the bulk viscosity coefficient to entropy density (ξ)/s . We assume that the bulk viscosity cosmological background fluid obeys the evolution equation of the steady truncated (Eckart) and full version of the Israel–Stewart fluid, respectively. -- Highlights: •In this paper we have studied quark–hadron phase transition in the early universe in the context of the Hořava–Lifshitz model. •We use a flat FRW universe with the bulk viscosity cosmological background fluid obeying the evolution equation of the steady truncated (Eckart) and full version of the Israel–Stewart fluid, respectively

  12. E.M. Freeman: early research on cereal diseases and the rise of plant pathology at the University of Minnesota.

    Science.gov (United States)

    Peterson, P D

    2001-01-01

    E.M. Freeman's role in early cereal disease research and the beginning of plant pathology at the University of Minnesota has been overshadowed largely by the enormous prestige of his student, E.C. Stakman. During the first decade of the twentieth century, Freeman was responsible for the transferral from Europe to the United States and the subsequent nurturing of important conceptual and technical developments in the area of cereal disease pathology. Under Freeman's leadership, these ideas would come to shape the direction of plant pathology research at the University of Minnesota for decades to follow.

  13. Early Opportunities Research Partnership Between Howard University, University of Maryland Baltimore County and NASA Goddard for Engaging Underrepresented STEM Students in Earth and Space Sciences

    Science.gov (United States)

    Misra, P.; Venable, D. D.; Hoban, S.; Demoz, B.; Bleacher, L.; Meeson, B. W.; Farrell, W. M.

    2017-12-01

    Howard University, University of Maryland Baltimore County and NASA Goddard Space Flight Center (GSFC) are collaborating to engage underrepresented STEM students and expose them to an early career pathway in NASA-related Earth & Space Science research. The major goal is to instill interest in Earth and Space Science to STEM majors early in their academic careers, so that they become engaged in ongoing NASA-related research, motivated to pursue STEM careers, and perhaps become part of the future NASA workforce. The collaboration builds on a program established by NASA's Dynamic Response of the Environments of Asteroids, the Moon and the moons of Mars (DREAM2) team to engage underrepresented students from Howard in summer internships. Howard leveraged this program to expand via NASA's Minority University Research and Education Project (MUREP) funding. The project pairs Howard students with GSFC mentors and engages them in cutting-edge Earth and Space Science research throughout their undergraduate tenure. The project takes a multi-faceted approach, with each year of the program specifically tailored to each student's strengths and addressing their weaknesses, so that they experience a wide array of enriching research and professional development activities that help them grow both academically and professionally. During the academic year, the students are at Howard taking a full load of courses towards satisfying their degree requirements and engaging in research with their GSFC mentors via regular telecons, e-mail exchanges, video chats & on an average one visit per semester to GSFC for an in-person meeting with their research mentor. The students extend their research with full-time summer internships at GSFC, culminating in a Capstone Project and Senior Thesis. As a result, these Early Opportunities Program students, who have undergone rigorous training in the Earth and Space Sciences, are expected to be well-prepared for graduate school and the NASA workforce.

  14. Early changes in volume and non-enhanced volume of acoustic neurinoma after stereotactic gamma-radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Hirofumi; Kobayashi, Tatsuya; Kida, Yoshihisa; Tanaka, Takayuki; Mori, Yoshimasa; Iwakoshi, Takayasu; Niwa, Masahiro; Kai, Osamu; Hirose, Mitsuhiko [Komaki City Hospital, Aichi (Japan)

    1994-09-01

    The effectiveness of stereotactic gamma-radiosurgery for treating acoustic neurinoma was evaluated by measuring the volumes of the tumor, non-enhanced tumor, and cerebellar edema in 13 patients with acoustic neurinoma who were followed up for 9 to 15 months (median 12.7 mos) after treatment. The tumor volume and non-enhanced volume tended to reach a maximum after 6 months, and cerebellar edema volume after 9 months, then decreased gradually thereafter. Hearing loss tended to increase gradually, but involvement of the facial nerve was transient. (author).

  15. Gas, Dust, and Quenching of Dusty Galaxies in the Early Universe

    Science.gov (United States)

    Spilker, Justin Scott

    In this dissertation, I study various aspects related to the gas and star formation in dusty star-forming galaxies in the distant universe. My dissertation is heavily based on observations made by the Atacama Large Millimeter/submillimeter Array (ALMA), observing a sample of gravitationally lensed high-redshift dusty galaxies originally discovered by the South Pole Telescope (SPT). In addition to the introductions to the individual chapters, Chapter 1 provides a broader background to the study of these objects and places them in the overall context of galaxy evolution. In Chapter 2 I describe a technique designed to search for faint molecular lines in the spectrum of high-redshift dusty galaxies. The brightest molecular lines in the spectra of these objects are due to carbon monoxide, but a host of other species are present in the interstellar media. These other molecules trace gas of a wide range of temperatures and densities, but are generally ten times fainter than the brighter CO lines. I detected several other molecular lines, and used them to characterize the conditions of the interstellar gas. This work was published in Spilker et al. (2014). In Chapter 3, I describe a technique for modeling the effects of gravitational lensing which is optimized for data from interferometers such as ALMA. Using these models and data for a large sample of objects from ALMA, I studied the intrinsic properties of the sample such as the source sizes and luminosities. I used these intrinsic properties to revisit topics from the literature which benefit from the additional size information I determined. This work was published in Spilker et al. (2016). In Chapter 4, I use the modeling technique I developed to investigate the relationship between the star formation and the cold molecular gas from which stars form in two objects selected from the SPT sample. Using the models of the source, I was able to determine the mass of molecular gas in these objects using several independent

  16. Pseudoscalar Fields in Torsionful Geometries of the Early Universe, the Baryon Asymmetry and Majorana Neutrino Mass Generation

    CERN Document Server

    Mavromatos, Nick E.

    2015-11-03

    We discuss here a specific field-theory model, inspired from string theory, in which the generation of a matter-antimatter asymmetry in the Cosmos is due to the propagation of fermions in a non-trivial, spherically asymmetric (and hence Lorentz violating) gravitational background that may characterise the epochs of the early universe. The background induces different dispersion relations, hence populations, between fermions and antifermions, and thus CPT Violation (CPTV) already in thermal equilibrium. Species populations may freeze out leading to leptogenesis and baryogenesis. More specifically, after reviewing some generic models of background-induced CPTV in early epochs of the Universe, we consider a string-inspired scenario, in which the CPTV is associated with a cosmological background with torsion provided by the Kalb-Ramond (KR) antisymemtric tensor field of the string gravitational multiplet. In a four-dimensional space time this field is dual to a pseudoscalar ``axion-like'' field. The thermalising ...

  17. Early growth rates and their relationships to mortalities of five breeds of chickens following exposure to acute gamma radiation stress

    International Nuclear Information System (INIS)

    Latimer, B.E.; Brisbin, I.L. Jr.

    1987-01-01

    Growth and mortality responses were recorded for 541 chicks, representing five different breeds of chickens, following acute exposures to gamma radiation stress at two days of age. Although there were no statistically significant differences in the LD50/30 of the five breeds studied, Cobb broilers showed the highest (1580R) and White Leghorn bantams the lowest (980R) levels, respectively. Other breeds studied included the standard White Leghorn, Athens Randombreds and a strain of feral bantam. Growth rates of body weights were proportionately more depressed by radiation stress than were body sizes, as measured by the lengths of the culmen, tarsus, middle toe and longest primary wing feather of all 32 day-old survivors. Among these structures, the length of the culmen seemed to be the least affected by radiation stress in all of the breeds studied. Feral bantams were able to tolerate the greatest depression in weight gain before exhibiting mortality at exposures below their LD50/30' while Cobb broilers tolerated the greatest depression of weight gain at higher exposure levels. There was a suggestion that those characteristics which were strongly selected for in the course of a particular breed's development were those which experienced the greatest proportional depressions following exposure to gamma radiation stress

  18. The Role of Early Maladaptive Schemas in Prediction of Dysfunctional Attitudes toward Drug Abuse among Students of university

    Directory of Open Access Journals (Sweden)

    NedaNaeemi

    2016-07-01

    Full Text Available Drug addiction as the most serious social issue of the world has different sociological, psychological, legal, and political aspects. In this regard, the purpose of this study is to determine the role of early maladaptive schemas in prediction of dysfunctional attitudes toward drug abuse among students of Islamic Azad Universities in Tehran Province, Iran. Statistical population of this study includes all students of Islamic Azad Universities in Tehran Province during 2013 and sample size is equal to 300 members that are randomly chosen. First, the name of university branches in Tehran Province were determined then three branches were randomly chosen out of them and then 300 members were chosen from those branches using random sampling method. All sample members filled out Young Schema Questionnaire Short Form and Dysfunctional Attitude Scale (DAS toward drug. Data were analyzed through regression correlation method and SPSS22 software. The obtained findings indicated a significant relation (P<0/05 between early maladaptive schemas and dysfunctional attitude toward drug abuse among students. Early maladaptive schemas can predict dysfunctional attitudes toward drug among students.

  19. Computational Cosmology: from the Early Universe to the Large Scale Structure

    Directory of Open Access Journals (Sweden)

    Peter Anninos

    1998-09-01

    Full Text Available In order to account for the observable Universe, any comprehensive theory or model of cosmology must draw from many disciplines of physics, including gauge theories of strong and weak interactions, the hydrodynamics and microphysics of baryonic matter, electromagnetic fields, and spacetime curvature, for example. Although it is difficult to incorporate all these physical elements into a single complete model of our Universe, advances in computing methods and technologies have contributed significantly towards our understanding of cosmological models, the Universe, and astrophysical processes within them. A sample of numerical calculations addressing specific issues in cosmology are reviewed in this article: from the Big Bang singularity dynamics to the fundamental interactions of gravitational waves; from the quark--hadron phase transition to the large scale structure of the Universe. The emphasis, although not exclusively, is on thosecalculations designed to test different models of cosmology against the observed Universe.

  20. Computational Cosmology: from the Early Universe to the Large Scale Structure

    Directory of Open Access Journals (Sweden)

    Anninos Peter

    2001-01-01

    Full Text Available In order to account for the observable Universe, any comprehensive theory or model of cosmology must draw from many disciplines of physics, including gauge theories of strong and weak interactions, the hydrodynamics and microphysics of baryonic matter, electromagnetic fields, and spacetime curvature, for example. Although it is difficult to incorporate all these physical elements into a single complete model of our Universe, advances in computing methods and technologies have contributed significantly towards our understanding of cosmological models, the Universe, and astrophysical processes within them. A sample of numerical calculations (and numerical methods applied to specific issues in cosmology are reviewed in this article: from the Big Bang singularity dynamics to the fundamental interactions of gravitational waves; from the quark-hadron phase transition to the large scale structure of the Universe. The emphasis, although not exclusively, is on those calculations designed to test different models of cosmology against the observed Universe.

  1. Computational Cosmology: From the Early Universe to the Large Scale Structure.

    Science.gov (United States)

    Anninos, Peter

    2001-01-01

    In order to account for the observable Universe, any comprehensive theory or model of cosmology must draw from many disciplines of physics, including gauge theories of strong and weak interactions, the hydrodynamics and microphysics of baryonic matter, electromagnetic fields, and spacetime curvature, for example. Although it is difficult to incorporate all these physical elements into a single complete model of our Universe, advances in computing methods and technologies have contributed significantly towards our understanding of cosmological models, the Universe, and astrophysical processes within them. A sample of numerical calculations (and numerical methods applied to specific issues in cosmology are reviewed in this article: from the Big Bang singularity dynamics to the fundamental interactions of gravitational waves; from the quark-hadron phase transition to the large scale structure of the Universe. The emphasis, although not exclusively, is on those calculations designed to test different models of cosmology against the observed Universe.

  2. Astronomy in the early years of elementary education: a partnership between university and school

    Science.gov (United States)

    Barai, A.; Carvalho Neto, J. T.; Garrido, D.; Ityanagui, G.; Navi, M.

    2016-12-01

    This paper describes the interaction and partnership experience between a school and one of the Federal University of São Carlos (UFSCar)campi, both located in Araras, SP, aiming to teach and promote astronomy and astronautics knowledge among students of the first five years of Elementary Education. This initiative made use of Brazilian Olympiad of Astronomy and Astronautics as a motivating event for the theme exploration. The actions were divided into two fronts: an improvement course for the school teachers conducted by university professors and lectures for students by UFSCar students under the guidance of university teachers and the school coordinators. By the observed results, we noticed the importance of narrowing the distance school-university, promoting learning for both institutions and helping to raise the level of education from elementary school to college.

  3. Campus-Wide Computing: Early Results Using Legion at the University of Virginia

    National Research Council Canada - National Science Library

    Grimshaw, Andrew S; Nguyen-Tuong, Anh; Wulf, William A

    2006-01-01

    The Legion project at the University of Virginia is an attempt to provide system services that provide the illusion of a single virtual machine to users, a virtual machine that provides both improved...

  4. Popular education in the mirror of the Popular University in France in the early XXth century

    Directory of Open Access Journals (Sweden)

    Lucien MERCIER

    2013-11-01

    Full Text Available The Popular Universities at the end of the XIXth century are a major reference in the history of popular education. The movement of the Popular Universities attracted militant workers and intellectual —writers, scientists, teachers and artists—, to educational dynamics which owe a lot to the Dreyfus Affair. This encounter of the morning coat with the workman's overalls didn't last long. The Popular Universities died because they were unable to imagine this mutual education which was everybody's dream. This failure marked people's minds for a long time, and the period between the two wars, full of experiences of working-class and proletarian education, constantly refers to the Popular Universities of the 1900^ to find a model to follow or to reject.

  5. The Construction and Empirical Analysis of Financial Risk Early Warning System in Colleges and Universities

    Directory of Open Access Journals (Sweden)

    Dai Jiaxu

    2017-03-01

    Full Text Available In recent years, China's higher education into the period of rapid development, high growth will inevitably bring high demand for financial support, but the government investment can not keep up with the pace of development of colleges and universities, so many colleges and universities choose bank loans, blind expansion will be out of control Resulting in college financial crisis. This paper proposes a method to construct the financial risk evaluation model of colleges and universities. The model is based on the specific risk index system, and uses the analytic hierarchy process and Delphi expert scoring method as the theoretical basis. The model can calculate the type and level of financial risk in colleges and universities, and provide support for the system decision-making.

  6. Universe

    CERN Document Server

    2009-01-01

    The Universe, is one book in the Britannica Illustrated Science Library Series that is correlated to the science curriculum in grades 5-8. The Britannica Illustrated Science Library is a visually compelling set that covers earth science, life science, and physical science in 16 volumes.  Created for ages 10 and up, each volume provides an overview on a subject and thoroughly explains it through detailed and powerful graphics-more than 1,000 per volume-that turn complex subjects into information that students can grasp.  Each volume contains a glossary with full definitions for vocabulary help and an index.

  7. Inflation of the early cold Universe filled with a nonlinear scalar field and a nonideal relativistic Fermi gas

    Energy Technology Data Exchange (ETDEWEB)

    Pashitskii, E. A., E-mail: pashitsk@iop.kiev.ua; Pentegov, V. I., E-mail: pentegov@iop.kiev.ua [National Academy of Sciences of Ukraine, Institute of Physics (Ukraine)

    2017-03-15

    We consider a possible scenario for the evolution of the early cold Universe born from a fairly large quantum fluctuation in a vacuum with a size a{sub 0} ≫ l{sub P} (where l{sub P} is the Planck length) and filled with both a nonlinear scalar field φ, whose potential energy density U(φ) determines the vacuum energy density λ, and a nonideal Fermi gas with short-range repulsion between particles, whose equation of state is characterized by the ratio of pressure P(n{sub F}) to energy density ε(n{sub F}) dependent on the number density of fermions n{sub F}. As the early Universe expands, the dimensionless quantity ν(n{sub F}) = P(n{sub F})/ε(n{sub F}) decreases with decreasing n{sub F} from its maximum value ν{sub max} = 1 for n{sub F} → ∞ to zero for n{sub F} → 0. The interaction of the scalar and gravitational fields, which is characterized by a dimensionless constant ξ, is proportional to the scalar curvature of four-dimensional space R = κ[3P(n{sub F})–ε(n{sub F})–4λ] (where κ is Einstein’s gravitational constant), and contains terms both quadratic and linear in φ. As a result, the expanding early Universe reaches the point of first-order phase transition in a finite time interval at critical values of the scalar curvature R = R{sub c} =–μ{sup 2}/ξ and radius a{sub c} ≫ a{sub 0}. Thereafter, the early closed Universe “rolls down” from the flat inflection point of the potential U(φ) to the zero potential minimum in a finite time. The release of the total potential energy of the scalar field in the entire volume of the expanding Universe as it “rolls down” must be accompanied by the production of a large number of massive particles and antiparticles of various kinds, whose annihilation plays the role of the Big Bang. We also discuss the fundamental nature of Newton’ gravitational constant G{sub N}.

  8. Inflation of the early cold Universe filled with a nonlinear scalar field and a nonideal relativistic Fermi gas

    International Nuclear Information System (INIS)

    Pashitskii, E. A.; Pentegov, V. I.

    2017-01-01

    We consider a possible scenario for the evolution of the early cold Universe born from a fairly large quantum fluctuation in a vacuum with a size a_0 ≫ l_P (where l_P is the Planck length) and filled with both a nonlinear scalar field φ, whose potential energy density U(φ) determines the vacuum energy density λ, and a nonideal Fermi gas with short-range repulsion between particles, whose equation of state is characterized by the ratio of pressure P(n_F) to energy density ε(n_F) dependent on the number density of fermions n_F. As the early Universe expands, the dimensionless quantity ν(n_F) = P(n_F)/ε(n_F) decreases with decreasing n_F from its maximum value ν_m_a_x = 1 for n_F → ∞ to zero for n_F → 0. The interaction of the scalar and gravitational fields, which is characterized by a dimensionless constant ξ, is proportional to the scalar curvature of four-dimensional space R = κ[3P(n_F)–ε(n_F)–4λ] (where κ is Einstein’s gravitational constant), and contains terms both quadratic and linear in φ. As a result, the expanding early Universe reaches the point of first-order phase transition in a finite time interval at critical values of the scalar curvature R = R_c =–μ"2/ξ and radius a_c ≫ a_0. Thereafter, the early closed Universe “rolls down” from the flat inflection point of the potential U(φ) to the zero potential minimum in a finite time. The release of the total potential energy of the scalar field in the entire volume of the expanding Universe as it “rolls down” must be accompanied by the production of a large number of massive particles and antiparticles of various kinds, whose annihilation plays the role of the Big Bang. We also discuss the fundamental nature of Newton’ gravitational constant G_N.

  9. Universal immunogenicity validation and assessment during early biotherapeutic development to support a green laboratory.

    Science.gov (United States)

    Bautista, Ami C; Zhou, Lei; Jawa, Vibha

    2013-10-01

    Immunogenicity support during nonclinical biotherapeutic development can be resource intensive if supported by conventional methodologies. A universal indirect species-specific immunoassay can eliminate the need for biotherapeutic-specific anti-drug antibody immunoassays without compromising quality. By implementing the R's of sustainability (reduce, reuse, rethink), conservation of resources and greener laboratory practices were achieved in this study. Statistical analysis across four biotherapeutics supported identification of consistent product performance standards (cut points, sensitivity and reference limits) and a streamlined universal anti-drug antibody immunoassay method implementation strategy. We propose an efficient, fit-for-purpose, scientifically and statistically supported nonclinical immunogenicity assessment strategy. Utilization of a universal method and streamlined validation, while retaining comparability to conventional immunoassays and meeting the industry recommended standards, provides environmental credits in the scientific laboratory. Collectively, individual reductions in critical material consumption, energy usage, waste and non-environment friendly consumables, such as plastic and paper, support a greener laboratory environment.

  10. Shelf-life extension of minimally processed and gamma irradiated red beet (Beta vulgaris ssp. vulgaris L.), Cv. early wonder

    International Nuclear Information System (INIS)

    Hernandes, Nilber Kenup; Vital, Helio de Carvalho; Coneglian, Regina Celi Cavestre

    2007-01-01

    This work investigated the effects of gamma irradiation on the shelf-life extension and safety of minimally processed red beet (Beta vulgaris ssp. vulgaris L.) by performing microbiological, chemical and sensory analyses. Red beets were harvested 73 days after transplanting and their tuberous parts were minimally processed and separated in two groups: control (non-irradiated) and irradiated (0.5, 1.0 and 1.5 kGy). Tests for Salmonella sp., total and fecal coliforms, total count of aerobic mesophilic and lactic-acid bacteria were performed during the 21-day storage at 8 deg C. They indicated that the samples irradiated with 1.0 and 1.5 kGy remained in good conditions throughout storage while the unirradiated samples did not last 7 days. Chemical analyses indicated that the concentrations of vitamins B1 and B2 were not affected by irradiation. In contrast the amounts of fructose and glucose increased during storage while the one for sucrose decreased. In addition four series of sensory evaluations including appearance and aroma indicated that the samples irradiated with 1.0 and 1.5 kGy remained good for consumption for 20 days. Therefore it was concluded that the use of the doses of 1.0 and 1.5 kGy produced the best effects on the conservation of the samples without harming the sensory characteristics and nutritional constituents tested. (author)

  11. Predicting Early Center Care Utilization in a Context of Universal Access

    Science.gov (United States)

    Zachrisson, Henrik Daae; Janson, Harald; Naerde, Ane

    2013-01-01

    This paper reports predictors for center care utilization prior to 18 months of age in Norway, a country with a welfare system providing up to one-year paid parental leave and universal access to subsidized and publicly regulated center care. A community sample of 1103 families was interviewed about demographics, family, and child characteristics…

  12. The first three minutes - 1990 version. [of early universe after Big Bang

    Science.gov (United States)

    Schramm, David N.

    1991-01-01

    The present state of understanding of what occurred in the universe's first three minutes is reviewed. Emphasis is on the events that lead to potentially observable consequences and that are model-independent or at least generic to broad classes of models. Inflation, phase transitions, dark matter, and nucleosynthesis are summarized.

  13. The emergence and early development of prosocial behavior: universalities and cultural specifications

    NARCIS (Netherlands)

    Song, Y.; Dubas, J.J.S.; Broekhuizen, M.L.

    2015-01-01

    Despite a long standing interest in the early development of prosocial behaviors, there is still considerable controversy about their origins and development. While some researchers propose that humans are born with a fundamental motivation to help, share and comfort others (nature), some

  14. Placement Supervision of Pedagogue Students in Denmark: The Role of University Colleges and Early Childhood Centres

    Science.gov (United States)

    Jensen, Jytte Juul

    2015-01-01

    The article examines Danish pedagogue students' supervision during their placement periods in early childhood settings. Throughout the long history of Danish pedagogue education, discourses relating to the placement element have been located either within a "work" paradigm or a "scholastic" paradigm. These two understandings of…

  15. Galactic chemical evolution in hierarchical formation models - I. Early-type galaxies in the local Universe

    NARCIS (Netherlands)

    Arrigoni, Matías; Trager, Scott C.; Somerville, Rachel S.; Gibson, Brad K.

    We study the metallicities and abundance ratios of early-type galaxies in cosmological semi-analytic models (SAMs) within the hierarchical galaxy formation paradigm. To achieve this we implemented a detailed galactic chemical evolution model and can now predict abundances of individual elements for

  16. Galactic chemical evolution in hierarchical formation models : I. Early-type galaxies in the local Universe

    NARCIS (Netherlands)

    Arrigoni, Matias; Trager, Scott C.; Somerville, Rachel S.; Gibson, Brad K.

    2010-01-01

    We study the metallicities and abundance ratios of early-type galaxies in cosmological semi-analytic models (SAMs) within the hierarchical galaxy formation paradigm. To achieve this we implemented a detailed galactic chemical evolution model and can now predict abundances of individual elements for

  17. Varying Gravitational Constant as Well as Cosmology from the Early Inflation to Late Acceleration and Future Universe

    OpenAIRE

    Srivastava, S. K.

    2008-01-01

    Here, cosmology is obtained from the variable gravitational constant $ G \\propto \\phi^{-2}$ with $ \\phi(x) $ being a scalar and its fluctuations around the ground state. The gravitational action contains Einstein-Hilbert like term with variable $ G $, kinetic energy and self-interaction potential for $ \\phi(x) $. Two phase transitions take place in this model. The first one takes place at the GUT (grand unified theory) scale $ \\sim 2.45 \\times 10^{14}{\\rm GeV} $, when the early universe exits...

  18. LiHe{sup +} IN THE EARLY UNIVERSE: A FULL ASSESSMENT OF ITS REACTION NETWORK AND FINAL ABUNDANCES

    Energy Technology Data Exchange (ETDEWEB)

    Bovino, Stefano; Tacconi, Mario; Gianturco, Francesco A. [Department of Chemistry, Universita degli Studi di Roma ' La Sapienza' , Piazzale A. Moro 5, 00185 Roma (Italy); Curik, Roman [J. Heyrovsky Institute of Physical Chemistry, Dolejskova 3, Prague (Czech Republic); Galli, Daniele, E-mail: fa.gianturco@caspur.it [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze (Italy)

    2012-06-10

    We present the results of quantum calculations based on entirely ab initio methods for a variety of molecular processes and chemical reactions involving the LiHe{sup +} ionic polar molecule. With the aid of these calculations, we derive accurate reaction rates and fitting expressions valid over a range of gas temperatures representative of the typical conditions of the pregalactic gas. With the help of a full chemical network, we then compute the evolution of the abundance of LiHe{sup +} as function of redshift in the early universe. Finally, we compare the relative abundance of LiHe{sup +} with that of other polar cations formed in the same redshift interval.

  19. Dynamical peculiarities of nucleo-genesis of light nuclei on the early stage of the Universe development

    International Nuclear Information System (INIS)

    Takibaev, N.Zh.; Spanova, G.A.

    2003-01-01

    The item of the L group chemical elements nuclei generation on the early stage of the Universe development has been studied. At this stage the thermodynamical equilibrium inside of nucleus, the electromagnetic and the neutrino component are passing at adiabatic matter expand condition. Description of hot hadron substance and light nuclei nucleo-genesis process are considered in the conditions of matter thermodynamical equilibrium. The approach of thermodynamical potential and state equation were used for analysis. The reactions balance in subsystems, including isotope group and neutron medium (for example, reactions in the hydrogen group) is studied. The assessments for disintegration channel influence are given

  20. In situ gamma spectrometry aspects of an European intercomparison of national networks used to provide early warning of a nuclear accident

    International Nuclear Information System (INIS)

    Gurriaran, R.; Lemercier, M.; Bouisset, P.; Cagnat, X.; Saez-Vergara, J. C.; Tyler, A. N.

    2006-01-01

    In 2002, the EURADOS Working Group on Environmental Monitoring organised the second European intercomparison exercise of national network systems used to provide early warning in case of a nuclear accident. The aim of the exercise is to ensure consistent and comparable results reported by different countries during a nuclear accident, hence avoiding that the dose rate measurements reported present steps at national borders due to different calibrations or different measurement quantities being used. The exercise studied the response of the detectors to different situations: Free field site, a flat area covered with grass. The detectors where in presence of environmental radiation and point sources. Radioactive plume simulator. An incident was simulated by gradually increasing the ambient dose rate by values up to 50% of the normal value. Cosmic radiation site. A platform installed in the middle of a lake permitted to study the response of detectors to cosmic rays in the absence of other components. Ultra low background laboratory (UDO). Situated at 925 m in a salt mine this unique facility has a very low ambient dose (<1 nSv/h) and permitted the study of the response of detectors to collimated beams, in the absence of other components. The exercise was focused on the systems that continuously monitor the ambient dose rate but a novelty in the 2002 intercomparison was the participation of in situ gamma spectrometry teams. This presentation will focus on the in situ gamma spectrometry aspects: The interest of having the energy spectra information in order to discriminate the different contributors to the ambient dose, and the work that has been done in order to ensure an agreement between the dosimetry aspects and the spectrometry results

  1. Was The Electromagnetic Spectrum A Blackbody Spectrum In The Early Universe?

    OpenAIRE

    Opher, Merav; Opher, Reuven

    1997-01-01

    It is assumed, in general, that the electromagnetic spectrum in the Primordial Universe was a blackbody spectrum in vacuum. We derive the electromagnetic spectrum, based on the Fluctuation-Dissipation Theorem that describes the electromagnetic fluctuations in a plasma. Our description includes thermal and collisional effects in a plasma. The electromagnetic spectrum obtained differs from the blackbody spectrum in vacuum at low frequencies. In particular, concentrating on the primordial nucleo...

  2. Early peroxisome proliferator-activated receptor gamma regulated genes involved in expansion of pancreatic beta cell mass

    Directory of Open Access Journals (Sweden)

    Vivas Yurena

    2011-12-01

    Full Text Available Abstract Background The progression towards type 2 diabetes depends on the allostatic response of pancreatic beta cells to synthesise and secrete enough insulin to compensate for insulin resistance. The endocrine pancreas is a plastic tissue able to expand or regress in response to the requirements imposed by physiological and pathophysiological states associated to insulin resistance such as pregnancy, obesity or ageing, but the mechanisms mediating beta cell mass expansion in these scenarios are not well defined. We have recently shown that ob/ob mice with genetic ablation of PPARγ2, a mouse model known as the POKO mouse failed to expand its beta cell mass. This phenotype contrasted with the appropriate expansion of the beta cell mass observed in their obese littermate ob/ob mice. Thus, comparison of these models islets particularly at early ages could provide some new insights on early PPARγ dependent transcriptional responses involved in the process of beta cell mass expansion Results Here we have investigated PPARγ dependent transcriptional responses occurring during the early stages of beta cell adaptation to insulin resistance in wild type, ob/ob, PPARγ2 KO and POKO mice. We have identified genes known to regulate both the rate of proliferation and the survival signals of beta cells. Moreover we have also identified new pathways induced in ob/ob islets that remained unchanged in POKO islets, suggesting an important role for PPARγ in maintenance/activation of mechanisms essential for the continued function of the beta cell. Conclusions Our data suggest that the expansion of beta cell mass observed in ob/ob islets is associated with the activation of an immune response that fails to occur in POKO islets. We have also indentified other PPARγ dependent differentially regulated pathways including cholesterol biosynthesis, apoptosis through TGF-β signaling and decreased oxidative phosphorylation.

  3. Helium-3 in Milky Way Reveals Abundance of Matter in Early Universe

    Science.gov (United States)

    2002-01-01

    Astronomers using the National Science Foundation's 140 Foot Radio Telescope in Green Bank, West Virginia, were able to infer the amount of matter created by the Big Bang, and confirmed that it accounts for only a small portion of the effects of gravity observed in the Universe. The scientists were able to make these conclusions by determining the abundance of the rare element helium-3 (helium with only one neutron and two protons in its nucleus) in the Milky Way Galaxy. The NRAO 140 Foot Radio Telescope The NRAO 140-Foot Radio Telescope "Moments after the Big Bang, protons and neutrons began to combine to form helium-3 and other basic elements," said Robert Rood of the University of Virginia. "By accurately measuring the abundance of this primordial element in our Galaxy today, we were able infer just how much matter was created when the Universe was only a few minutes old." Rood and his colleagues, Thomas Bania from Boston University and Dana Balser from the National Radio Astronomy Observatory (NRAO), report their findings in the January 3 edition of the scientific journal Nature. Rood began searching for helium-3 in the Milky Way Galaxy in 1978. At that time, scientists believed that stars like our Sun synthesized helium-3 in their nuclear furnaces. Surprisingly, Rood's observations indicated that there was far less of this element in the Galaxy than the current models predicted. "If stars were indeed producing helium-3, as scientists believed, then we should have detected this element in much greater concentrations," he said. This unexpected discovery prompted Rood and his colleagues to broaden their search, and to look throughout the Milky Way for signs of stellar production of helium-3. Over the course of two decades, the researchers discovered that regardless of where they looked -- whether in the areas of sparse star formation like the outer edges of the Galaxy, or in areas of intense star formation near center of the Galaxy -- the relative abundance of

  4. QCD phase transition in the laboratory and in the early universe

    International Nuclear Information System (INIS)

    Sinha, Bikash

    1998-01-01

    It is expected that two nuclei colliding at ultra-relativistic energies (∼ 200 GeV/nucleon or more) may lead to hadronic matter go through a phase transition to its fundamental constituents, quarks and gluons, usually referred to as quark gluon plasma (QGP). Somewhat analogously, the universe, as per conventional wisdom should have consisted of quarks, gluons, leptons and photons, a microsecond after the Big Bang. The experience and wisdom, expected from nucleus-nucleus collisions in the laboratory and anticipated to facilitate our understanding of the quark-hadron phase transition. Indeed what possible footprints of that primordial epoch can be traced in today's cosmos is one of the interesting and intriguing questions. In this paper, the following areas will be focused: the issue of successive thermal and chemical equilibrium scenarios; a detailed study of hot hadronic matter and its implication on the thermal model; and finally, the surviving quark nuggets beyond a critical baryon content, and, nuggets being possible candidates for baryonic dark matter in the universe, a much more straightforward candidate than illusive actions or SUSY particles. It is our considered view that quark hadron phase transition in the microsecond universe is a thriving area of research and lot more can be understood and known from this primordial event. (author)

  5. Clinical Analysis of stereotactic body radiation therapy using extracranial gamma knife for patients with mainly bulky inoperable early stage non-small cell lung carcinoma

    Directory of Open Access Journals (Sweden)

    Tang Hanjun

    2011-07-01

    Full Text Available Abstract Purpose To evaluate the clinical efficacy and toxicity of stereotactic body radiation therapy (SBRT using extracranial gamma knife in patients with mainly bulky inoperable early stage non-small cell lung carcinoma (NSCLC. Materials and methods A total of 43 medically inoperable patients with mainly bulky Stage I/II NSCLC received SBRT using gamma knife were reviewed. The fraction dose and the total dose were determined by the radiation oncologist according to patients' general status, tumor location, tumor size and the relationship between tumor and nearby organ at risk (OAR. The total dose of 34~47.5 Gy was prescribed in 4~12 fractions, 3.5~10 Gy per fraction, one fraction per day or every other day. The therapeutic efficacy and toxicity were evaluated. Results The median follow-up was 22 months (range, 3-102 months. The local tumor response rate was 95.35%, with CR 18.60% (8/43 and PR 76.74% (33/43, respectively. The local control rates at 1, 2, 3, 5 years were 77.54%, 53.02%, 39.77%, and 15.46%, respectively, while the 1- and 2-year local control rates were 75% and 60% for tumor ≤3 cm; 84% and 71% for tumor sized 3~5 cm; 55% and 14.6% for tumor sized 5~7 cm; and 45%, 21% in those with tumor size of >7 cm. The overall survival rate at 1, 2, 3, 5 years were 92.04%, 78.04%, 62.76%, 42.61%, respectively. The toxicity of stereotactic radiation therapy was grade 1-2. Clinical stages were significantly important factor in local control of lung tumors (P = 0.000. Both clinical stages (P = 0.015 and chemotherapy (P = 0.042 were significantly important factors in overall survival of lung tumors. Conclusion SBRT is an effective and safe therapy for medically inoperable patients with early stage NSCLC. Clinical stage was the significant prognostic factors for both local tumor control and overall survival. The toxicity is mild. The overall local control for bulky tumors is poor. Tumor size is a poor prognostic factor, and the patients for

  6. Post-recombination early Universe cooling by translation-internal inter-conversion: The role of minor constituents.

    Science.gov (United States)

    McCaffery, Anthony J

    2015-09-14

    Little is known of the mechanism by which H and H2, the principal constituents of the post-re-combination early Universe, cooled sufficiently to permit cluster formation, nucleosynthesis, and, eventually, the formation of structured objects. Radiative decay primarily cools the internal modes of H2, as Δj = - 2 jumps accompany quadrupolar emission. This, however, would be a self-limiting mechanism. In this work, a translational energy cooling mechanism based on collision-induced, translation-to-internal mode conversion, is extended, following an earlier study [A. J. McCaffery and R. J. Marsh, J. Chem. Phys. 139, 234310 (2013)] of ensembles comprising H2 in a H atom bath gas. Here, the possible influence of minor species, such as HD, on this cooling mechanism is investigated. Results suggest that the influence of HD is small but not insignificant. Conversion is very rapid and an overall translation-to-internal energy conversion efficiency of some 5% could be expected. This finding may be of use in the further development of models of this complex phase of early Universe evolution. An unexpected finding in this study was that H2 + HD ensembles are capable of very rapid translation-to-internal conversion with efficiencies of >40% and relaxation rates that appear to be relatively slow. This may have potential as an energy storage mechanism.

  7. Wave function of the Universe in the early stage of its evolution

    International Nuclear Information System (INIS)

    Maydanyuk, Sergei P.

    2008-01-01

    In quantum cosmological models, constructed in the framework of Friedmann-Robertson-Walker metrics, a nucleation of the Universe with its further expansion is described as a tunneling transition through an effective barrier between regions with small and large values of the scale factor a at non-zero (or zero) energy. The approach for describing this tunneling consists of constructing a wave function satisfying an appropriate boundary condition. There are various ways for defining the boundary condition that lead to different estimates of the barrier penetrability and the tunneling time. In order to describe the escape from the tunneling region as accurately as possible and to construct the total wave function on the basis of its two partial solutions unambiguously, we use the tunneling boundary condition that the total wave function must represent only the outgoing wave at the point of escape from the barrier, where the following definition for the wave is introduced: the wave is represented by the wave function whose modulus changes minimally under a variation of the scale factor a. We construct a new method for a direct non-semiclassical calculation of the total stationary wave function of the Universe, analyze the behavior of this wave function in the tunneling region, near the escape point and in the asymptotic region, and estimate the barrier penetrability. We observe oscillations of the modulus of the wave function in the external region starting from the turning point which decrease with increasing of a and which are not shown in semiclassical calculations. The period of such an oscillation decreases uniformly with increasing a and can be used as a fully quantum dynamical characteristic of the expansion of the Universe. (orig.)

  8. A second Higgs doublet in the early universe. Baryogenesis and gravitational waves

    International Nuclear Information System (INIS)

    Dorsch, G.C.; Konstandin, T.; Huber, S.J.; No, J.M.; King's College, London

    2016-11-01

    We show that simple Two Higgs Doublet models still provide a viable explanation for the matter-antimatter asymmetry of the Universe via electroweak baryogenesis, even after taking into account the recent order-of-magnitude improvement on the electron-EDM experimental bound by the ACME Collaboration. Moreover we show that, in the region of parameter space where baryogenesis is possible, the gravitational wave spectrum generated at the end of the electroweak phase transition is within the sensitivity reach of the future space-based interferometer LISA.

  9. Was The Electromagnetic Spectrum A Blackbody Spectrum In The Early Universe?

    International Nuclear Information System (INIS)

    Opher, M.; Opher, R.

    1997-01-01

    It is generally assumed that the electromagnetic spectrum in the primordial universe was a blackbody spectrum in vacuum. We derive the electromagnetic spectrum based on the fluctuation-dissipation theorem that describes the electromagnetic fluctuations in a plasma. Our description includes thermal and collisional effects in a plasma. The electromagnetic spectrum obtained differs from a blackbody spectrum in vacuum at low frequencies. In particular, concentrating on the primordial nucleosynthesis era, it has more energy than the blackbody spectrum for frequencies less than 3ω pe to 6ω pe , where ω pe is the electron plasma frequency. copyright 1997 The American Physical Society

  10. A second Higgs doublet in the early universe. Baryogenesis and gravitational waves

    Energy Technology Data Exchange (ETDEWEB)

    Dorsch, G.C.; Konstandin, T. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Huber, S.J. [Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy; No, J.M. [Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy; King' s College, London (United Kingdom). Dept. of Physics

    2016-11-15

    We show that simple Two Higgs Doublet models still provide a viable explanation for the matter-antimatter asymmetry of the Universe via electroweak baryogenesis, even after taking into account the recent order-of-magnitude improvement on the electron-EDM experimental bound by the ACME Collaboration. Moreover we show that, in the region of parameter space where baryogenesis is possible, the gravitational wave spectrum generated at the end of the electroweak phase transition is within the sensitivity reach of the future space-based interferometer LISA.

  11. A second Higgs doublet in the early universe: baryogenesis and gravitational waves

    Energy Technology Data Exchange (ETDEWEB)

    Dorsch, G.C.; Konstandin, T. [DESY, Notkestraße 85, D-22607 Hamburg (Germany); Huber, S.J.; No, J.M., E-mail: glauber.dorsch@desy.de, E-mail: s.huber@sussex.ac.uk, E-mail: thomas.konstandin@desy.de, E-mail: jose_miguel.no@kcl.ac.uk [Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom)

    2017-05-01

    We show that simple Two Higgs Doublet models might still provide a viable explanation for the matter-antimatter asymmetry of the Universe via electroweak baryogenesis, even after taking into account the recent order-of-magnitude improvement on the electron-EDM experimental bound by the ACME Collaboration. Moreover we show that, in the region of parameter space where baryogenesis may be possible, the gravitational wave spectrum generated at the end of the electroweak phase transition is within the sensitivity reach of the future space-based interferometer LISA.

  12. Implementation of quality management in early stages of research and development projects at a university.

    Science.gov (United States)

    Fiehe, Sandra; Wagner, Georg; Schlanstein, Peter; Rosefort, Christiane; Kopp, Rüdger; Bensberg, Ralf; Knipp, Peter; Schmitz-Rode, Thomas; Steinseifer, Ulrich; Arens, Jutta

    2014-04-01

    The ultimate objective of university research and development projects is usually to create knowledge, but also to successfully transfer results to industry for subsequent marketing. We hypothesized that the university technology transfer requires efficient measures to improve this important step. Besides good scientific practice, foresighted and industry-specific adapted documentation of research processes in terms of a quality management system might improve the technology transfer. In order to bridge the gap between research institute and cooperating industry, a model project has been accompanied by a project specific amount of quality management. However, such a system had to remain manageable and must not constrain the researchers' creativity. Moreover, topics and research team are strongly interdisciplinary, which entails difficulties regarding communication because of different perspectives and terminology. In parallel to the technical work of the model project, an adaptable quality management system with a quality manual, defined procedures, and forms and documents accompanying the research, development and validation was implemented. After process acquisition and analysis the appropriate amount of management for the model project was identified by a self-developed rating system considering project characteristics like size, innovation, stakeholders, interdisciplinarity, etc. Employees were trained according to their needs. The management was supported and the technical documentation was optimized. Finally, the quality management system has been transferred successfully to further projects.

  13. [The early years of anatomy and obstetrics at the Göttingen University, 1734-1760].

    Science.gov (United States)

    Rab, Irén

    2014-03-16

    In the Age of Enlightenment medical education was based on new fundamentals. According to experts at that time, a medical faculty had to have five branches: anatomy, botany, chemistry, practical and theoretical medicine. Perhaps Göttingen was the most successful university foundation at that time, because a generous financial support was provided, outstanding professors were invited and an education without censorship was warranted. The spirit of Enlightenment affected both the structure and the standards of education of the facultas medicinae. The word-wide reputation of this faculty was earned by Albrecht von Haller. Haller conceived both the still highly regarded botanical garden and the anatomical theatre, which was the first of its kind in the German speaking area. Furthermore, he founded one of the first clinical obstetrics departments in the world. Students gained theoretical knowledge, were trained practically and had the opportunity to make scientific observations and medical experiments. This paper describes the founding era of the medical faculty of University of Göttingen from a historical-cultural view of point, based on contemporary documents from Germany and Hungary.

  14. The Cumulative Disadvantages of Socially Toxic Family Environments: A Comparison of Early Life Experiences of Incarcerated Men and University Students

    Directory of Open Access Journals (Sweden)

    Joseph Michalski

    2017-12-01

    Full Text Available The paper examines the antecedents of criminal behavior through the process of retrospective family and life course histories in which incarcerated male inmates and male university students are compared. The main focus is on early childhood experiences and parental behaviors. The study data derive from intensive, face-to-face interviews with 38 men incarcerated for violent offences and a matched group of 66 men attending university at the same time. The interviews focus on the relative importance of adverse childhood experiences and linkages with adolescence. The interviews demonstrated that nearly four-fifths of the inmates experienced toxic family environments by the time they reached adolescence, as compared with only two of the university students. Qualitative analyses flesh out the major themes, experiences, and “risk factors” that helped shape the trajectories of both groups of men. The socially toxic family environments and sub-optimal parenting practices that most inmates endured produced long-term, adverse effects in reducing their capacities for resilience, forging healthy relationships with their peers, and remaining in school.

  15. Entropy in the Present and Early Universe: New Small Parameters and Dark Energy Problem

    Directory of Open Access Journals (Sweden)

    Alexander Shalyt-Margolin

    2010-04-01

    Full Text Available It is demonstrated that entropy and its density play a significant role in solving the problem of the vacuum energy density (cosmological constant of the Universe and hence the dark energy problem. Taking this in mind, two most popular models for dark energy—Holographic Dark Energy Model and Agegraphic Dark Energy Model—are analysed. It is shown that the fundamental quantities in the first of these models may be expressed in terms of a new small dimensionless parameter that is naturally occurring in High Energy Gravitational Thermodynamics and Gravitational Holography (UV-limit. On this basis, the possibility of a new approach to the problem of Quantum Gravity is discussed. Besides, the results obtained on the uncertainty relation of the pair “cosmological constant–volume of space-time”, where the cosmological constant is a dynamic quantity, are reconsidered and generalized up to the Generalized Uncertainty Relation.

  16. Relation Between Early Maladaptive Schemes and Anxiety and Depression Features in University Students

    Directory of Open Access Journals (Sweden)

    Diana Lucía Sánchez-Ortíz***

    2009-12-01

    Full Text Available Anxiety and depression are important health problems, because of the high prevalence rates in normal population and in clinical population. This non-experimental study intends to identify the cognitive profile, through the early maladaptive schemes in students from the Universidad Pontificia Bolivariana Bucaramanga, related with depression and anxiety scores. Thegoal is to contribute to the identification of cognitive characteristics that could help in the prevention of these disorders. 259 psychology students of the first seven semesters were evaluated by means from the following questionnaires: BDI, ST/DEP, STAI and YSQ-L2. The results don’t show the presence of specific schemes as a function of the presence of State/ Trait depression or State/Trait anxiety, which might suggest, through the dimensional paradigm, the presence of a cognitive pattern for an anxiety and depression mix disorder. It is suggested that further research should be carried out with other samples, including clinical population.

  17. Geneva University

    CERN Multimedia

    2009-01-01

    École de physique - Département de physique nucléaire et corpusculaire 24, quai Ernest-Ansermet 1211 GENÈVE 4 Tél: (022) 379 62 73 - Fax: (022) 379 69 92 Wednesday 13 May 2009 PARTICLE PHYSICS SEMINAR at 17:00 – Stückelberg Auditorium Observing the extreme universe with the Fermi Gamma-ray Space Telescope Prof. Olaf Reimer / Stanford University The Fermi Gamma-ray Space Telescope (FGST, formerly GLAST) is an international observatory-type satellite mission with a physics program spanning from gamma-ray astronomy to particle astrophysics and cosmology. FGST was launched on June 11, 2008 and is successfully conducting science observations of the high-energy gamma-ray sky since August 2008. A varienty of discoveries has been made already, including monitoring rapid blazar variability, the existence of GeV gamma-ray bursts, and numerous new gamma-ray sources of different types, including those belonging to previously unknown gamma-ray source classes like msPSRs, globula...

  18. Early nursing career experience for 1994-2000 graduates from the University of Nottingham.

    Science.gov (United States)

    Park, Jennifer R; Chapple, Mary; Wharrad, Heather; Bradley, Sue

    2007-05-01

    This paper reports the views of nurses graduating from the University of Nottingham School of Nursing, UK, 1994-2000, Bachelor of Nursing (Hons) course, concerning career aspirations, progress and reflections on their qualification. Alongside academic knowledge and practical skills, this four-year Bachelor of Nursing course aimed to develop students' critical thinking and research skills. The degree's effect on nurses' career trajectories is unknown. Self-completion questionnaires employing open and closed questions were sent to graduates 9 months after graduation and at intervals over the next 6 years. Most respondents were confident and motivated in their nursing careers. Promotion, increased responsibility, further study, specialization and qualifications were career priorities. Recent qualifiers also focused on changing jobs, travel and working overseas. The graduates' experience has salience for nurse managers, especially when matching graduates against post outlines within the knowledge and skills framework, considering staff skill mix, and advising graduates about their development and assisting them to find satisfaction in their nursing careers.

  19. Early Gas Stripping as the Origin of the Darkest Galaxies in the Universe

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Lucio; /Zurich, ETH /Zurich U.; Kazantzidis, Stelios; /KIPAC, Menlo Park /KICP, Chicago; Mastropietro, Chiara; /Munich U. Observ.; Wadsley, James; /McMaster U.

    2007-02-28

    The known galaxies most dominated by dark matter (Draco, Ursa Minor and Andromeda IX) are satellites of the Milky Way and the Andromeda galaxies. They are members of a class of faint galaxies, devoid of gas, known as dwarf spheroidals, and have by far the highest ratio of dark to luminous matter. None of the models proposed to unravel their origin can simultaneously explain their exceptional dark matter content and their proximity to a much larger galaxy. Here we report simulations showing that the progenitors of these galaxies were probably gas-dominated dwarf galaxies that became satellites of a larger galaxy earlier than the other dwarf spheroidals. We find that a combination of tidal shocks and ram pressure swept away the entire gas content of such progenitors about ten billion years ago because heating by the cosmic ultraviolet background kept the gas loosely bound: a tiny stellar component embedded in a relatively massive dark halo survived until today. All luminous galaxies should be surrounded by a few extremely dark-matter-dominated dwarf spheroidal satellites, and these should have the shortest orbital periods among dwarf spheroidals because they were accreted early.

  20. Extracting gravitational waves induced by plasma turbulence in the early Universe through an averaging process

    International Nuclear Information System (INIS)

    Garrison, David; Ramirez, Christopher

    2017-01-01

    This work is a follow-up to the paper, ‘Numerical relativity as a tool for studying the early Universe’. In this article, we determine if cosmological gravitational waves can be accurately extracted from a dynamical spacetime using an averaging process as opposed to conventional methods of gravitational wave extraction using a complex Weyl scalar. We calculate the normalized energy density, strain and degree of polarization of gravitational waves produced by a simulated turbulent plasma similar to what was believed to have existed shortly after the electroweak scale. This calculation is completed using two numerical codes, one which utilizes full general relativity calculations based on modified BSSN equations while the other utilizes a linearized approximation of general relativity. Our results show that the spectrum of gravitational waves calculated from the nonlinear code using an averaging process is nearly indistinguishable from those calculated from the linear code. This result validates the use of the averaging process for gravitational wave extraction of cosmological systems. (paper)

  1. Gamma Knife

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Gamma Knife Gamma Knife® is a radiation therapy that uses computerized ... If you're scheduled for radiation therapy using Gamma Knife®, a treatment team consisting of a radiation ...

  2. Does a phase transition in the early universe produce the conditions needed for inflation

    International Nuclear Information System (INIS)

    Mazenko, G.F.; Unruh, W.G.; Wald, R.M.

    1985-01-01

    In the standard ''new inflationary scenario,'' it is assumed that when the Higgs field phi is cooled below its phase-transition temperature T/sub c/ it is found in a metastable state which has negligible kinetic and spatial-derivative energy but has large, positive potential energy V 0 . Hence, in this picture, the stress-energy tensor of phi is of the form T/sub a/b = -V 0 g/sub ab/ and remains of this form until the state becomes unstable and ''rolls down the hill'' to its true minimum at phi = phi/sub c/. With this stress-energy tensor Einstein's equation for a Robertson-Walker model predicts expansion of the universe on an exponential time scale, i.e., inflation. We argue here that, at least in many possible models this standard picture of the behavior of phi as it is cooled to T/sub c/ and below is wrong. Rather than be ''supercooled'' to a state with phiroughly-equal0 locally, the field should rapidly form domains with phi near +- phi/sub c/. The dynamics of the phase transition is governed by the growth and coalescence of these domains, not by a ''roll down the hill'' of the spatially averaged value of phi. Furthermore, the stress-energy tensor of phi does not take the form needed to produce inflation. Our arguments are based mainly on physical reasoning, but they are supported by the known behavior of certain condensed-matter systems

  3. Nursing habits and early childhood caries in children attending Hospital University Science Malaysia (HUSM

    Directory of Open Access Journals (Sweden)

    Widowati Witjaksono

    2006-06-01

    Full Text Available The habit of nocturnal bottle or breast-feeding has been reported to be a potential cause for early childhood caries (ECC in very young children. The aim of this study was to determine the prevalence of ECC in children 2-5 years of age attending out patient clinic HUSM, in relation to the nursing habits. In this cross-sectional study, 90 children were randomly selected to examine their caries status using torch and disposable mirror. Data on mothers’ educational level, nursing habits and oral hygiene practices, were gather by using structured questionnaire. It has been found that 16.7% of subjects were caries free while 83.3% of them had caries with mean dmf score 6 (SD 5.3. With regard to nursing habits, 29% of subjects had breast-feeding alone, 16% had bottle-feeding alone and 55% had both breast and bottle-feeding. Ninety-three percent of children had been nursed beyond 14 months and 47% had been fed with liquids other than breast milk, infant formula or water. Twenty-seven percent of children were allowed to sleep with nursing bottle in mouth and 52% were allowed to sleep with breast nipple in the mouth which shows significantly associated with ECC (p = 0.03. Tooth brushing habit was reported for 91% of children using toothpaste. Mean age of the children (in months when the mothers started brushing the teeth was 19.1 (SD 10.8 and has significant association with ECC (p < 0.05. This study demonstrates that the habit of allowing infants to sleep with breast nipple in their mouth and the late start of tooth brushing are associated with prevalence of ECC. Educational programs for pregnant women and mothers of young children should be emphasized to enhance the knowledge and awareness of mothers in preventing ECC.

  4. Swift: A gamma ray burst MIDEX

    International Nuclear Information System (INIS)

    Barthelmy, Scott

    2001-01-01

    Swift is a first of its kind multiwavelength transient observatory for gamma-ray burst astronomy. It has the optimum capabilities for the next breakthroughs in determining the origin of gamma-ray bursts and their afterglows as well as using bursts to probe the early Universe. Swift will also perform the first sensitive hard X-ray survey of the sky. The mission is being developed by an international collaboration and consists of three instruments, the Burst Alert Telescope (BAT), the X-ray Telescope (XRT), and the Ultraviolet and Optical Telescope (UVOT). The BAT, a wide-field gamma-ray detector, will detect ∼1 gamma-ray burst per day with a sensitivity 5 times that of BATSE. The sensitive narrow-field XRT and UVOT will be autonomously slewed to the burst location in 20 to 70 seconds to determine 0.3-5.0 arcsec positions and perform optical, UV, and X-ray spectrophotometry. On-board measurements of redshift will also be done for hundreds of bursts. Swift will incorporate superb, low-cost instruments using existing flight-spare hardware and designs. Strong education/public outreach and follow-up programs will help to engage the public and astronomical community. Swift has been selected by NASA for development and launch in late 2003

  5. Dynamical 3-Space Predicts Hotter Early Universe: Resolves CMB-BBN 7-Li and 4-He Abundance Anomalies

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2010-01-01

    Full Text Available The observed abundances of 7-Li and 4-He are significantly inconsistent with the predictions from Big Bang Nucleosynthesis (BBN when using the $Lambda$CDM cosmological model together with the value for $Omega_B h^2 = 0.0224pm0.0009$ from WMAP CMB fluctuations, with the value from BBN required to fit observed abundances being $0.009 < Omega_B h^2 < 0.013$. The dynamical 3-space theory is shown to predict a 20% hotter universe in the radiation-dominated epoch, which then results in a remarkable parameter-free agreement between the BBN and the WMAP value for $Omega_B h^2$. The dynamical 3-space also gives a parameter-free fit to the supernova redshift data, and predicts that the flawed $Lambda$CDM model would require $Omega_Lambda = 0.73$ and $Omega_M = 0.27$ to fit the 3-space dynamics Hubble expansion, and independently of the supernova data. These results amount to the discovery of new physics for the early universe that is matched by numerous other successful observational and experimental tests.

  6. Dynamical 3-Space Predicts Hotter Early Universe: Resolves CMB-BBN 7-Li and 4-He Abundance Anomalies

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2010-01-01

    Full Text Available The observed abundances of 7 Li and 4 He are significantly inconsistent with the pre- dictions from Big Bang Nucleosynthesis (BBN when using the CDM cosmolog- ical model together with the value for B h 2 = 0 : 0224 0 : 0009 from WMAP CMB fluctuations, with the value from BBN required to fit observed abundances being 0 : 009 < B h 2 < 0 : 013. The dynamical 3-space theory is shown to predict a 20% hot- ter universe in the radiation-dominated epoch, which then results in a remarkable parameter-free agreement between the BBN and the WMAP value for B h 2 . The dy- namical 3-space also gives a parameter-free fit to the supernova redshift data, and pre- dicts that the flawed CDM model would require = 0 : 73 and M = 0 : 27 to fit the 3-space dynamics Hubble expansion, and independently of the supernova data. These results amount to the discovery of new physics for the early universe that is matched by numerous other successful observational and experimental tests.

  7. Description and Early Outcomes of a Comprehensive Curriculum Redesign at the Northwestern University Feinberg School of Medicine.

    Science.gov (United States)

    Heiman, Heather L; O'Brien, Celia L; Curry, Raymond H; Green, Marianne M; Baker, James F; Kushner, Robert F; Thomas, John X; Corbridge, Thomas C; Corcoran, Julia F; Hauser, Joshua M; Garcia, Patricia M

    2017-09-26

    In 2012, the Northwestern University Feinberg School of Medicine launched a redesigned curriculum addressing the four primary recommendations in the 2010 Carnegie Foundation for the Advancement of Teaching report on reforming medical education. This new curriculum provides a more standardized evaluation of students' competency achievement through a robust portfolio review process coupled with standard evaluations of medical knowledge and clinical skills. It individualizes learning processes through curriculum flexibility, enabling students to take electives earlier and complete clerkships in their preferred order. The new curriculum is integrated both horizontally and vertically, combining disciplines within organ-based modules and deliberately linking elements (science in medicine, clinical medicine, health and society, professional development) and threads (medical decision making, quality and safety, teamwork and leadership, lifestyle medicine, advocacy and equity) across the three phases that replaced the traditional four-year timeline. It encourages students to conduct research in an area of interest and commit to lifelong learning and self-improvement. The curriculum formalizes the process of professional identity formation and requires students to reflect on their experiences with the informal and hidden curricula, which strongly shape their identities.The authors describe the new curriculum structure, explain their approach to each Carnegie report recommendation, describe early outcomes and challenges, and propose areas for further work. Early data from the first cohort to progress through the curriculum show unchanged United States Medical Licensing Examination Step 1 and 2 scores, enhanced student research engagement and career exploration, and improved student confidence in the patient care and professional development domains.

  8. Airborne and total gamma absorbed dose rates at Patiala - India

    International Nuclear Information System (INIS)

    Tesfaye, Tilahun; Sahota, H.S.; Singh, K.

    1999-01-01

    The external gamma absorbed dose rate due to gamma rays originating from gamma emitting aerosols in air, is compared with the total external gamma absorbed dose rate at the Physics Department of Punjabi University, Patiala. It has been found out that the contribution, to the total external gamma absorbed dose rate, of radionuclides on particulate matter suspended in air is about 20% of the overall gamma absorbed dose rate. (author)

  9. Lunar based gamma ray astronomy

    International Nuclear Information System (INIS)

    Haymes, R.C.

    1985-01-01

    Gamma ray astronomy represents the study of the universe on the basis of the electromagnetic radiation with the highest energy. Gamma ray astronomy provides a crucial tool for the understanding of astronomical phenomena, taking into account nucleosynthesis in supernovae, black holes, active galaxies, quasars, the sources of cosmic rays, neutron stars, and matter-antimatter annihilation. Difficulties concerning the conduction of studies by gamma ray astronomy are related to the necessity to perform such studies far from earth because the atmosphere is a source of gamma rays. Studies involving the use of gamma ray instruments in earth orbit have been conducted, and more gamma ray astronomy observations are planned for the future. Imperfections of studies conducted in low earth orbit could be overcome by estalishing an observatory on the moon which represents a satellite orbiting at 60 earth radii. Details concerning such an observatory are discussed. 5 references

  10. Early experience with the da Vinci® surgical system robot in gynecological surgery at King Abdulaziz University Hospital

    Directory of Open Access Journals (Sweden)

    Sait KH

    2011-07-01

    Full Text Available Khalid H SaitObstetrics and Gynecology Department, Faculty of Medicine, Gynecology Oncology Unit, King Abdulaziz University Hospital, Jeddah, Saudi ArabiaBackground: The purpose of this study was to review our experience and the challenges of using the da Vinci® surgical system robot during gynecological surgery at King Abdulaziz University Hospital.Methods: A retrospective study was conducted to review all cases of robot-assisted gynecologic surgery performed at our institution between January 2008 and December 2010. The patients were reviewed for indications, complications, length of hospital stay, and conversion rate, as well as console and docking times.Results: Over the three-year period, we operated on 35 patients with benign or malignant conditions using the robot for a total of 62 surgical procedures. The docking times averaged seven minutes. The mean console times for simple hysterectomy, bilateral salpingo-oophorectomy, and bilateral pelvic lymphadenectomy were 125, 47, and 62 minutes, respectively. In four patients, laparoscopic procedures were converted to open procedures, giving a conversion rate of 6.5%. All of the conversions were among the first 15 procedures performed. The average hospital stay was 3 days. Complications occurred in five patients (14%, and none were directly related to the robotic system.Conclusion: Our early experience with the robot show that with proper training of the robotic team, technical difficulty with the robotic system is limited. There is definitely a learning curve that requires performance of gynecological surgical procedures using the robot.Keywords: da Vinci robot, gynecological surgery, laparoscopy

  11. The Gamma-ray Sky with Fermi

    Science.gov (United States)

    Thompson, David

    2012-01-01

    Gamma rays reveal extreme, nonthermal conditions in the Universe. The Fermi Gamma-ray Space Telescope has been exploring the gamma-ray sky for more than four years, enabling a search for powerful transients like gamma-ray bursts, novae, solar flares, and flaring active galactic nuclei, as well as long-term studies including pulsars, binary systems, supernova remnants, and searches for predicted sources of gamma rays such as dark matter annihilation. Some results include a stringent limit on Lorentz invariance derived from a gamma-ray burst, unexpected gamma-ray variability from the Crab Nebula, a huge gamma-ray structure associated with the center of our galaxy, surprising behavior from some gamma-ray binary systems, and a possible constraint on some WIMP models for dark matter.

  12. Inhaled /sup 239/PuO/sub 2/ and/or total-body gamma radiation: Early mortality and morbidity in rats and dogs

    Energy Technology Data Exchange (ETDEWEB)

    Filipy, R.E.; Decker, J.R.; Lai, Y.L.; Lauhala, K.E.; Buschbom, R.L.; Hiastala, M.P.; McGee, D.R.; Park, J.F.; Kuffel, E.G.; Ragan, H.A.; Cannon, W.C.; Yaniv, S.S.; Scott, B.R.

    1988-08-01

    Rats and beagle dogs were given doses of /sup 60/Co gamma radiation and/or body burdens of /sup 239/PuO/sub 2/ within lethal ranges in an experiment to determine and compare morbidity and mortality responses of both species within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell concentrations and by long-term loss of body weight and diminished pulmonary function in animals of both species that survived the acute gamma radiation syndrome. Inhaled plutonium caused a loss of body weight and diminished pulmonary function in both species, but its only effect on blood cell concentrations was lymphocytopenia in dogs. Combined gamma irradiation and plutonium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Plutonium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the long-term effect of plutonium lung burdens in both species. Rats were less sensitive to both kinds of radiation, whether administered alone or in combination. 71 refs., 105 figs., 48 tabs.

  13. Inhaled 239PuO2 and/or total-body gamma radiation: Early mortality and morbidity in rats and dogs

    International Nuclear Information System (INIS)

    Filipy, R.E.; Decker, J.R.; Lai, Y.L.

    1988-08-01

    Rats and beagle dogs were given doses of 60 Co gamma radiation and/or body burdens of 239 PuO 2 within lethal ranges in an experiment to determine and compare morbidity and mortality responses of both species within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell concentrations and by long-term loss of body weight and diminished pulmonary function in animals of both species that survived the acute gamma radiation syndrome. Inhaled plutonium caused a loss of body weight and diminished pulmonary function in both species, but its only effect on blood cell concentrations was lymphocytopenia in dogs. Combined gamma irradiation and plutonium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Plutonium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the long-term effect of plutonium lung burdens in both species. Rats were less sensitive to both kinds of radiation, whether administered alone or in combination. 71 refs., 105 figs., 48 tabs

  14. Application of low-dose gamma irradiation to extend the shelf life of minimally processed Red Beet (Beta vulgaris sp. vulgaris L.), cv. Early Wonder

    International Nuclear Information System (INIS)

    Hernandez, Nilber Kenup

    2006-01-01

    This study was aimed at investigating the effects of low-dose gamma irradiation on shelf-life extension and phyto sanitary safety of minimally processed red beet with basis on physicochemical; microbiological; chemical and sensory analyses. The samples (Beta vulgaris ssp. vulgaris L.), Early Wonder cultivar, were cultivated in the experimental area of the Horticulture Sector of the Departamento de Fitotecnia of the Instituto de Agronomia, Universidade Federal Rural do Rio de Janeiro, Seropedica, RJ, as part of two experiments performed during the second semester of 2005. In each experiment, 1200 plants (40 per linear meter of terrain) were sowed. Physicochemical analyses (fresh mass; length; average diameter and total soluble solids) of the edible part of the red beets (their tuberous roots) were periodically carried out in order to assess the most appropriate time for harvest by monitoring the development of the plants. Those times were found to be 104 and 73 days after transplanting, respectively. The harvested edible part of the roots were minimally processed and separated in two groups: (1) gamma irradiated (with doses of 0.5; 1.0 and 1.5 kGy) and (2) non-irradiated (control). All samples were stored at 8 degree C. Microbiological analyses were performed during the storage period (22 and 21 days, for experiments 1 and 2, respectively) in order to evaluate the phyto sanitary quality of the samples (Salmonella sp.; coliforms and total count of mesophilic aerobic and lactic acid bacteria). The samples irradiated with 1.0 and 1.5 kGy were found to remain appropriate for consumption for 21 days, as compared to only 7 days for the control. Monitoring of chemical composition was also performed and included the determination of saccharose; glucose; fructose and vitamins B1 and B2. No difference was found between the concentrations of those vitamins in irradiated and control samples at the end of the storage period, whereas significant changes in sugar contents were

  15. Towards comprehensive early abortion service delivery in high income countries: insights for improving universal access to abortion in Australia

    Directory of Open Access Journals (Sweden)

    Angela Dawson

    2016-10-01

    Full Text Available Abstract Background Improving access to safe abortion is an essential strategy in the provision of universal access to reproductive health care. Australians are largely supportive of the provision of abortion and its decriminalization. However, the lack of data and the complex legal and service delivery situation impacts upon access for women seeking an early termination of pregnancy. There are no systematic reviews from a health services perspective to help direct health planners and policy makers to improve access comprehensive medical and early surgical abortion in high income countries. This review therefore aims to identify quality studies of abortion services to provide insight into how access to services can be improved in Australia. Methods We undertook a structured search of six bibliographic databases and hand-searching to ascertain peer reviewed primary research in English between 2005 and 2015. Qualitative and quantitative study designs were deemed suitable for inclusion. A deductive content analysis methodology was employed to analyse selected manuscripts based upon a framework we developed to examine access to early abortion services. Results This review identified the dimensions of access to surgical and medical abortion at clinic or hospital-outpatient based abortion services, as well as new service delivery approaches utilising a remote telemedicine approach. A range of factors, mostly from studies in the United Kingdom and United States of America were found to facilitate improved access to abortion, in particular, flexible service delivery approaches that provide women with cost effective options and technology based services. Standards, recommendations and targets were also identified that provided services and providers with guidance regarding the quality of abortion care. Conclusions Key insights for service delivery in Australia include the: establishment of standards, provision of choice of procedure, improved provider

  16. Gamma Ray Bursts

    Science.gov (United States)

    Gehrels, Neil; Meszaros, Peter

    2012-01-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma-rays coming from the cosmos. They occur roughly once per day ,last typically lOs of seconds and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this review we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglows.

  17. Needling the early universe

    International Nuclear Information System (INIS)

    Hawkins, I.; Wright, E.L.

    1988-01-01

    The possibility that the whole microwave background can be produced by a bright population of pregalactic stars at a redshift of a few hundred is explored. The radiation is thermalized by a combination of amorphous silicate, amorphous carbon, graphite, and needle-shaped conducting grains which give rise to the opacity needed at wavelengths greater than 3 cm. The occurrence of distortion in a primordial microwave background spectrum due to its interaction with Population III stars and dust is investigated. The possibility of producing deviations small enough to be consistent with the best available observations, but still detectable by COBE, is considered. 65 references

  18. Early stages of universe

    International Nuclear Information System (INIS)

    Aldrovandi, R.

    1975-04-01

    In a very simplified, descriptive way, the main trends of phenomenological cosmology are reviewed. A sketchy view of the fashionable Standard Model(1,2) is considered preliminarly its most pretentious variant, the Symmetric Model, is then introduced [pt

  19. The Early Universe

    Science.gov (United States)

    Fowler, William

    It is a great honor to have been invited to deliver the Fourth B.M. Birla Memorial Lecture following in the footsteps of Fred Hoyle, Philip Morrison and Abdus Salam. I must express my gratitude to Dr. B.G. Sidharth, Director of the Birla Science Centre, for all he has done to make the arrangements for the travel here and the stay here of my wife and myself so pleasant and so comfortable. Finally we are most grateful to Mr. and Mrs. G.P. Birla for their gracious hospitality at their home and its beautiful gardens here in Hyderabad.

  20. The role of Fe and Ni for s-process nucleosynthesis in the early Universe and for innovative nuclear technologies

    CERN Multimedia

    Manousos, A; Heil, M; Plag, R

    The early universe was enriched in heavy elements by massive stars via their s- and r-process contributions. Ultra metal-poor stars were found to show abundance patterns that scale exactly with the solar r component. While this holds exactly for elements heavier than barium, there is still confusion about significant discrepancies in the mass region below A ${\\leq}$ 120. It is known that massive stars contribute significantly to the abundances between Fe and Zr. This so-called weak s-process component was found to exhibit large uncertainties due to the poorly known cross sections, especially in the Fe- i region. In view of this problem it is proposed to perform accurate state-of-the art measurements on highly enriched samples of the stable Fe and Ni isotopes at the n_TOF facility. Transformation of these results into significantly improved stellar cross section rates will allow to disentangle the s and r contributions observed in the oldest stars for a reliable comparison with galactic chemical evolution mode...

  1. Etiological pattern and early outcome of patients presenting with obstructive jaundice at isra university hospital, hyderabad, pakistan

    International Nuclear Information System (INIS)

    Bhanbhro, R.J.; Maheshwari, T.; Jarwar, M.

    2017-01-01

    Objective: To determine the etiological pattern and early outcome of patients presenting with obstructive jaundice. Methodology: This prospective case series was conducted on 82 patients through convenient sampling for one year from July 2010 to June 2011 at Isra University Hospital, Hyderabad, Pakistan. All patients with obstructive jaundice were included in this study. After making final diagnosis, depending upon the etiology and stage of disease, the patient was offered the appropriate treatment. SPSS version 16.0 was used to for data analysis. Results: Mean age of the participants was 54.16+-11.50. Males were predominant as compare to females, 57.3% and 42.7%. Gallstones were the most common cause; seen in 74 (90.2%) patients. Seventy (96.3%) were managed conservatively as compare to those patients in which surgery performed (1 case, 1.2%). 97.6% improved and were discharged where as 2(1.64%) did not improve. Conclusion: Gallstones were the predominant cause of obstructive jaundice in our setup. Most of the patients did not require surgical treatment, and outcome was very good with conservative treatment. (author)

  2. Lessons learned from early direct measurements at Fukushima Medical University after the Fukushima Nuclear Power Station accident

    Energy Technology Data Exchange (ETDEWEB)

    Miyazaki, Makoto; Ohba, Takashi; Ohtsuru, Akira [Fukushima Medical Univ., Dept. of Radiation Health Management, Fukushima, Fukushima (Japan)

    2012-11-15

    The Fukushima Daiichi Nuclear Power Station (FDNPS) accident resulted in a month-long discharge of radioactive materials into the environment. These radioactive materials were detected at Fukushima Medical University (FMU), which is 57 km northwest of the FDNPS. Significant levels of six nuclides (i.e., {sup 131}I, {sup 132}Te, {sup 132}I, {sup 133}Xe, {sup 134}Cs, and {sup 137}Cs) were detected by a whole body counter (WBC) on March 15, 2011 when the ambient dose rate was suddenly elevated for the first time. This WBC has a dual detector system consisting of two NaI(Tl) detectors and two Ge detectors. We conducted periodical measurements of 32 humans and the background using the WBC. Because the three nuclides {sup 131}I, {sup 134}Cs and {sup 137}Cs were still detected in the background by the WBC a few months after the accident, accurate WBC measurements were difficult. Here we describe the limitations of our measurements conducted in the early stage of the FDNPS accident. (author)

  3. The Origin of Dust in the Early Universe: Probing the Star Formation History of Galaxies by Their Dust Content

    Science.gov (United States)

    Dwek, Eli; Cherchneff, Isabelle

    2010-01-01

    Two distinct scenarios for the origin of the approximately 4 x 10(exp 8) Solar Mass of dust observed in the high-redshift (z = 6.4) quasar J1148+5251 have been proposed. The first assumes that this galaxy is much younger than the age of the universe at that epoch so that only supernovae, could have produced this dust. The second scenario assumes a significantly older galactic age, so that the dust could have formed in lower-mass AGB stars. Presenting new integral solutions for the chemical evolution of metals and dust in galaxies, we offer a critical evaluation of these two scenarios. ^N;"(,, show that the AGB scenario is sensitive to the details of the galaxy's star formation history (SFH), which must consist of an early intense starburst followed by a period of low stellar activity. The presence or absence of massive amounts of dust in high-redshift galaxies can therefore be used to infer their SFH. However, a problem with the AGB scenario is that it produces a stellar mass that is significantly larger than the inferred dynamical mass of J1148+5251, an yet unresolved discrepancy. If this problem persists, then additional sites for the growth or formation of dust, such as molecular clouds or dense clouds around active galactic nuclei, must be considered.

  4. Test Review for Preschool-Wide Evaluation Tool (PreSET) Manual: Assessing Universal Program-Wide Positive Behavior Support in Early Childhood

    Science.gov (United States)

    Rodriguez, Billie Jo

    2013-01-01

    The Preschool-Wide Evaluation Tool (PreSET; Steed & Pomerleau, 2012) is published by Paul H. Brookes Publishing Company in Baltimore, MD. The PreSET purports to measure universal and program-wide features of early childhood programs' implementation fidelity of program-wide positive behavior intervention and support (PW-PBIS) and is,…

  5. Role Model Effects of Female STEM Teachers and Doctors on Early 20th Century University Enrollment in California. Research & Occasional Paper Series: CSHE.10.16

    Science.gov (United States)

    Bleemer, Zach

    2016-01-01

    What was the role of imperfect local information in the growth, gender gap, and STEM (Science, Technology, Engineering and Math) major selection of early 20th century American universities? In order to examine pre-1950 American higher education, this study constructs four rich panel datasets covering most students, high school teachers, and…

  6. Continuity, Support, Togetherness and Trust: Findings from an Evaluation of a University-Administered Early Professional Development Programme for Teachers in England

    Science.gov (United States)

    McIntyre, Joanna; Hobson, Andrew J.; Mitchell, Nick

    2009-01-01

    This article discusses the evaluation of a unique university-based early professional development (EPD) programme in England that enabled newly and recently qualified teachers to have continued contact with their initial teacher preparation provider. The programme was designed to enhance the induction, EPD and retention of beginning teachers of…

  7. Gamma-Ray Bursts: A Radio Perspective

    Directory of Open Access Journals (Sweden)

    Poonam Chandra

    2016-01-01

    Full Text Available Gamma-ray bursts (GRBs are extremely energetic events at cosmological distances. They provide unique laboratory to investigate fundamental physical processes under extreme conditions. Due to extreme luminosities, GRBs are detectable at very high redshifts and potential tracers of cosmic star formation rate at early epoch. While the launch of Swift and Fermi has increased our understanding of GRBs tremendously, many new questions have opened up. Radio observations of GRBs uniquely probe the energetics and environments of the explosion. However, currently only 30% of the bursts are detected in radio bands. Radio observations with upcoming sensitive telescopes will potentially increase the sample size significantly and allow one to follow the individual bursts for a much longer duration and be able to answer some of the important issues related to true calorimetry, reverse shock emission, and environments around the massive stars exploding as GRBs in the early Universe.

  8. Early and late effects of fission-neutron or gamma irradiation on the clearance of bacteria from the lungs of B6CF1 mice

    International Nuclear Information System (INIS)

    Brennan, P.C.; Ainsworth, E.J.

    1977-01-01

    Enhanced susceptibility to experimental respiratory infection following chronic exposure to low-level gamma radiation has been reported, but no comparable information exists for neutron-irradiated animals. Such information is needed in view of the apparently greater additivity of repeated low fission-neutron doses. Consequently altered susceptibility to respiratory infection is being examined in the JANUS Neutron and Gamma-Ray Toxicity Program. Some B6CF 1 mice of various ages were challenged with Pasteurella pneumotropica either by intranasal instillation or by aerosol inhalation following single or fractionated doses of neutrons or 60 Co gamma radiation. Clearance of the bacteria from the lungs was assessed 4 days after challenge by a culture technique and by histological and immunofluorescence staining. From 5 to 21 days after a single dose of 288 neutron rads or 740 gamma rads, a ratio equal to the relative biological effectiveness (RBE) for cell killing, there was little repair of the radiation-damaged clearance mechanism evident in neutron-irradiated mice; 85% were unable to clear the organism as long as 21 days after irradiation. Over the same period only 25% of gamma-irradiated mice failed to eliminate P. pneumotropica. Immunofluorescent-stained lung sections at all time intervals between 5 and 21 days were strikingly similar among neutron- and gamma-irradiated mice and unirradiated mice. Alveolar macrophages were swollen with fluorescent P. pneumotropica cells, and macrophages surrounding the bronchi and in the bronchial exudate were also intensely fluorescent. These data, coupled with the culture data, indicate that pulmonary macrophages in the irradiated host are capable of engulfing P. pneumotropica cells but that the ability to kill them is impaired

  9. Modellierung dreidimensionaler Strahlungsfelder im frühen Universum %t Modelling three dimensional radiation fields in the early universe

    Science.gov (United States)

    Meinköhn, Erik

    2002-11-01

    The present work aims at the modelling of three-dimensional radiation fields in gas clouds from the early universe, in particular as to the influence of varying distributions of density and velocity. In observations of high-redshift gas clouds, the Lyα transition from the first excited energy level to the ground state of the hydrogen atom is usually found to be the only prominent emission lines in the entire spectrum. It is a well-known assumption that high-redshifted hydrogen clouds are the precursors of present-day galaxies. Thus, the investigation of the Lyα line is of paramount importance of the theory of galaxy formation and evolution. The observed Lyα line - or rather, to be precise, its profile - reveals both the complexity of the spatial distribution and of the kinematics of the interstellar gas, and also the nature of the photon source. In this thesis we have developed a code which is capable of solving the three-dimensional frequency-dependent radiative transfer equation for arbitrarily nonrelativistically moving media. The numerical treatment of the associated partial integro-differential equation is an extremely challenging task, since radiation intensity depends on 6 variables, namely 3 space variables, 2 variables describing the direction of photon propagation, and the frequency. With the goal of a quantitative comparison with observational data in mind, the implementation of very efficient methods for a sufficiently accurate solution of the complex radiative transfer problems turned out to be a necessity. The size of the resulting linear system of equations makes the use of parallelization techniques and grid refinement strategies indispensable.

  10. A Development of a Knowledge Management Model of Supervision of Practicum Students in Early Childhood Education, Faculty of Education, Mahasarakham University

    Directory of Open Access Journals (Sweden)

    Srikunyarphat Rangsriborwornkul

    2017-06-01

    Full Text Available The purpose of this study was to develop a model of knowledge management of supervision of practicum students in early childhood education. The target groups were 1 four supervisors in Early Childhood Education program, faculty of Education, Mahasarakham University and 2 thirty-three fifth-year practicum students in early childhood education practicing in professional experience at schools which located in Mahasarakham, Khonkaen, and Roi-Et provinces. The research tool was a survey form of supervision of practicum students. Content analysis was used. The research findings showed that 1 a development of the knowledge management model of supervision of practicum students in early childhood education contained 3 phases: phase I – studying need assessment, phase II – developing a model and phase III – conclusion and 2 data from the survey form of knowledge management of supervision categorized into two aspects, namely, appropriate practices and inappropriate practices.

  11. EDGE: Explorer of diffuse emission and gamma-ray burst explosions

    DEFF Research Database (Denmark)

    Den Herder, J.W.; Hermsen, W.; Hoevers, H.

    2007-01-01

    cluster formation, down to the very low redshift Universe, when between a third and one half of the baryons are expected to reside in cosmic filaments undergoing gravitational collapse by dark matter (the so-called warm hot intragalactic medium). In addition EDGE, with its unprecedented capabilities......How structures of various scales formed and evolved from the early Universe up to present time is a fundamental question of astrophysics. EDGE1 will trace the cosmic history of the baryons from the early generations of massive stars by Gamma-Ray Burst (GRB) explosions, through the period of galaxy...

  12. EDGE: Explorer of diffuse emission and gamma-ray burst explosions

    DEFF Research Database (Denmark)

    Piro, L; den Herder, J W; Ohashi, T

    2009-01-01

    , through the period of galaxy cluster formation, down to the very low redshift Universe, when between a third and one half of the baryons are expected to reside in cosmic filaments undergoing gravitational collapse by dark matter (the so-called warm hot intragalactic medium). In addition EDGE, with its......How structures of various scales formed and evolved from the early Universe up to present time is a fundamental question of astrophysical cosmology. EDGE (Piro et al., 2007) will trace the cosmic history of the baryons from the early generations of massive stars by Gamma-Ray Burst (GRB) explosions...

  13. Cell Death of Gamma Interferon-Stimulated Human Fibroblasts upon Toxoplasma gondii Infection Induces Early Parasite Egress and Limits Parasite Replication

    NARCIS (Netherlands)

    Niedelman, Wendy; Sprokholt, Joris K.; Clough, Barbara; Frickel, Eva-Maria; Saeij, Jeroen P. J.

    2013-01-01

    The intracellular protozoan parasite Toxoplasma gondii is a major food-borne illness and opportunistic infection for the immunosuppressed. Resistance to Toxoplasma is dependent on gamma interferon (IFN-γ) activation of both hematopoietic and nonhematopoietic cells. Although IFN-γ-induced innate

  14. Cell death of gamma interferon-stimulated human fibroblasts upon toxoplasma gondii infection induces early parasite egress and limits parasite replication

    NARCIS (Netherlands)

    Niedelman, W.; Sprokholt, J.K.; Clough, B.; Frickel, E.; Saeij, J.P.J.

    2013-01-01

    The intracellular protozoan parasite Toxoplasma gondii is a major food-borne illness and opportunistic infection for the immunosuppressed. Resistance to Toxoplasma is dependent on gamma interferon (IFN-¿) activation of both hematopoietic and nonhematopoietic cells. Although IFN-¿-induced innate

  15. Gamma astronomy

    International Nuclear Information System (INIS)

    Cesarsky, C.; Cesarsky, J.P.

    1986-01-01

    This article overviews the gamma astronomy research. Sources already observed, and what causes to give to them; the galactic radiation and its interpretation; techniques already used and current projects [fr

  16. Gamma Spectroscopy

    NARCIS (Netherlands)

    Niemantsverdriet, J.W.; Butz, Tilman; Ertl, G.; Knözinger, H.; Schüth, F.

    2008-01-01

    No abstract. The sections in this article are 1 Introduction 2 Mössbauer Spectroscopy 3 Time-Differential Perturbed Angular Correlations (TDPAC) 4 Conclusions and Outlook Keywords: Mössbauer spectroscopy; gamma spectroscopy; perturbed angular correlation; TDPAC

  17. A gamma scintillation spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Symbalisty, S

    1952-07-01

    A scintillation type gamma ray spectrometer employing coincidence counting, designed and built at the Physics Department of the University of Western Ontario is described. The spectrometer is composed of two anthracene and photomultiplier radiation detectors, two pulse analyzing channels, a coincidence stage, three scalers and a high voltage stabilized supply. A preliminary experiment to test the operation of the spectrometer was performed and the results of this test are presented. (author)

  18. Gamma-Ray Lenses for Astrophysics-and the Gamma-Ray Imager Mission GRI

    DEFF Research Database (Denmark)

    Wunderer, C. B.; Ballmoos, P. V.; Barriere, N.

    2009-01-01

    Observations of the gamma-ray sky reveal the most powerful sources and the most violent events in the Universe. While at lower wavebands the observed emission is generally dominated by thermal processes, the gamma-ray sky provides us with a view on the non-thermal Universe. Here particles are acc...

  19. Baryogenesis model predicting antimatter in the Universe

    International Nuclear Information System (INIS)

    Kirilova, D.

    2003-01-01

    Cosmic ray and gamma-ray data do not rule out antimatter domains in the Universe, separated at distances bigger than 10 Mpc from us. Hence, it is interesting to analyze the possible generation of vast antimatter structures during the early Universe evolution. We discuss a SUSY-condensate baryogenesis model, predicting large separated regions of matter and antimatter. The model provides generation of the small locally observed baryon asymmetry for a natural initial conditions, it predicts vast antimatter domains, separated from the matter ones by baryonically empty voids. The characteristic scale of antimatter regions and their distance from the matter ones is in accordance with observational constraints from cosmic ray, gamma-ray and cosmic microwave background anisotropy data

  20. The Role of the Emperor’s University of Kazan in the History of Formation of Tatar Musical Ethnography (XIX – Early ХХ Century

    Directory of Open Access Journals (Sweden)

    Elmira I. Safiullina

    2014-03-01

    Full Text Available The article reveals the role of the Emperor’s University of Kazan of the XIX-early ХХ century in the history of formation of Tatar musical ethnography. Special attention is paid to activities of scientific organizations at the Emperor’s University of Kazan. Based on the study of manuscripts stored at the Department of Manuscripts and Rare Books at the N.I. Lobachevsky Scientific Library, the article gives information concerning the Asian Musical Magazine by I. Dobrovolsky, as well as the Society for Archeology, History and Ethnography. The author concludes that the Emperor’s University of Kazan has an important role in formation of Tatar musical ethnography.

  1. An Empirical Determination of the Intergalactic Background Light Using Near-Infrared Deep Galaxy Survey Data Out to 5 Micrometers and the Gamma-Ray Opacity of the Universe

    Science.gov (United States)

    Scully, Sean T.; Malkan, Matthew A.; Stecker, Floyd W.

    2014-01-01

    We extend our previous model-independent determination of the intergalactic background light, based purely on galaxy survey data, out to a wavelength of 5 micrometers. Our approach enables us to constrain the range of photon densities, based on the uncertainties from observationally determined luminosity densities and colors. We further determine a 68% confidence upper and lower limit on the opacity of the universe to gamma-rays up to energies of 1.6/(1 + z) terraelectron volts. A comparison of our lower limit redshift-dependent opacity curves to the opacity limits derived from the results of both ground-based air Cerenkov telescope and Fermi-LAT observations of PKS 1424+240 allows us to place a new upper limit on the redshift of this source, independent of IBL modeling.

  2. Compton Gamma-Ray Observatory

    Science.gov (United States)

    1991-01-01

    This photograph shows the Compton Gamma-Ray Observatory (GRO) being deployed by the Remote Manipulator System (RMS) arm aboard the Space Shuttle Atlantis during the STS-37 mission in April 1991. The GRO reentered Earth atmosphere and ended its successful mission in June 2000. For nearly 9 years, the GRO Burst and Transient Source Experiment (BATSE), designed and built by the Marshall Space Flight Center (MSFC), kept an unblinking watch on the universe to alert scientists to the invisible, mysterious gamma-ray bursts that had puzzled them for decades. By studying gamma-rays from objects like black holes, pulsars, quasars, neutron stars, and other exotic objects, scientists could discover clues to the birth, evolution, and death of stars, galaxies, and the universe. The gamma-ray instrument was one of four major science instruments aboard the Compton. It consisted of eight detectors, or modules, located at each corner of the rectangular satellite to simultaneously scan the entire universe for bursts of gamma-rays ranging in duration from fractions of a second to minutes. In January 1999, the instrument, via the Internet, cued a computer-controlled telescope at Las Alamos National Laboratory in Los Alamos, New Mexico, within 20 seconds of registering a burst. With this capability, the gamma-ray experiment came to serve as a gamma-ray burst alert for the Hubble Space Telescope, the Chandra X-Ray Observatory, and major gound-based observatories around the world. Thirty-seven universities, observatories, and NASA centers in 19 states, and 11 more institutions in Europe and Russia, participated in the BATSE science program.

  3. Gamma camera

    International Nuclear Information System (INIS)

    Berninger, W.H.

    1975-01-01

    The light pulse output of a scintillator, on which incident collimated gamma rays impinge, is detected by an array of photoelectric tubes each having a convexly curved photocathode disposed in close proximity to the scintillator. Electronic circuitry connected to outputs of the phototubes develops the scintillation event position coordinate electrical signals with good linearity and with substantial independence of the spacing between the scintillator and photocathodes so that the phototubes can be positioned as close to the scintillator as is possible to obtain less distortion in the field of view and improved spatial resolution as compared to conventional planar photocathode gamma cameras

  4. Gamma-Ray Astronomy Technology Needs

    Science.gov (United States)

    Gehrels, N.; Cannizzo, J. K.

    2012-01-01

    In recent decades gamma-ray observations have become a valuable tool for studying the universe. Progress made in diverse 8re1lS such as gamma-ray bursts (GRBs), nucleosynthesis, and active galactic nuclei (AGNs) has complimented and enriched our astrophysical understanding in many ways. We present an overview of current and future planned space y-ray missions and discussion technology needs for- the next generation of space gamma-ray instruments.

  5. Cross-Section of Hadron Production in $\\gamma\\gamma$ Collisions at LEP

    CERN Document Server

    Acciarri, M; Aguilar-Benítez, M; Ahlen, S P; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alverson, G; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Baksay, L; Banerjee, S; Banerjee, Sw; Banicz, K; Barczyk, A; Barillère, R; Barone, L; Bartalini, P; Baschirotto, A; Basile, M; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Bilei, G M; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böck, R K; Böhm, A; Boldizsar, L; Borgia, B; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brigljevic, V; Brock, I C; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Busenitz, J K; Button, A M; Cai, X D; Campanelli, M; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chang, Y H; Chaturvedi, U K; Chekanov, S V; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chéreau, X J; Chiefari, G; Chien, C Y; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Cohn, H O; Coignet, G; Colijn, A P; Colino, N; Commichau, V; Costantini, S; Cotorobai, F; de la Cruz, B; Csilling, Akos; Dai, T S; D'Alessandro, R; De Asmundis, R; Degré, A; Deiters, K; Della Volpe, D; Denes, P; De Notaristefani, F; DiBitonto, Daryl; Diemoz, M; Van Dierendonck, D N; Di Lodovico, F; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dova, M T; Duchesneau, D; Duinker, P; Durán, I; Dutta, S; Easo, S; Efremenko, Yu V; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ernenwein, J P; Extermann, Pierre; Fabre, M; Faccini, R; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Fenyi, B; Ferguson, T; Ferroni, F; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisk, I; Forconi, G; Fredj, L; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gau, S S; Gentile, S; Gheordanescu, N; Giagu, S; Goldfarb, S; Goldstein, J; Gong, Z F; Gougas, Andreas; Gratta, Giorgio; Grünewald, M W; Gupta, V K; Gurtu, A; Gutay, L J; Hartmann, B; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Van Hoek, W C; Hofer, H; Hong, S J; Hoorani, H; Hou, S R; Hu, G; Innocente, Vincenzo; Jenkes, K; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kasser, A; Khan, R A; Kamrad, D; Kamyshkov, Yu A; Kapustinsky, J S; Karyotakis, Yu; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, D H; Kim, J K; Kim, S C; Kim, Y G; Kinnison, W W; Kirkby, A; Kirkby, D; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Kopp, A; Korolko, I; Koutsenko, V F; Krämer, R W; Krenz, W; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lapoint, C; Lassila-Perini, K M; Laurikainen, P; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Le Goff, J M; Leiste, R; Leonardi, E; Levchenko, P M; Li Chuan; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lu, W; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Majumder, G; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Mangla, S; Marchesini, P A; Marin, A; Martin, J P; Marzano, F; Massaro, G G G; McNally, D; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mi, Y; Mihul, A; Van Mil, A J W; Mirabelli, G; Mnich, J; Molnár, P; Monteleoni, B; Moore, R; Morganti, S; Moulik, T; Mount, R; Müller, S; Muheim, F; Muijs, A J M; Nahn, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Niessen, T; Nippe, A; Nisati, A; Nowak, H; Oh, Yu D; Opitz, H; Organtini, G; Ostonen, R; Palomares, C; Pandoulas, D; Paoletti, S; Paolucci, P; Park, H K; Park, I H; Pascale, G; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Peach, D; Pei, Y J; Pensotti, S; Perret-Gallix, D; Petersen, B; Petrak, S; Pevsner, A; Piccolo, D; Pieri, M; Pinto, J C; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Produit, N; Prokofev, D; Prokofiev, D O; Rahal-Callot, G; Raja, N; Rancoita, P G; Rattaggi, M; Raven, G; Razis, P A; Read, K; Ren, D; Rescigno, M; Reucroft, S; Van Rhee, T; Riemann, S; Riles, K; Robohm, A; Rodin, J; Roe, B P; Romero, L; Rosier-Lees, S; Rosselet, P; Van Rossum, W; Roth, S; Rubio, Juan Antonio; Ruschmeier, D; Rykaczewski, H; Salicio, J; Sánchez, E; Sanders, M P; Sarakinos, M E; Sarkar, S; Sassowsky, M; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schmitz, P; Scholz, N; Schopper, Herwig Franz; Schotanus, D J; Schwenke, J; Schwering, G; Sciacca, C; Sciarrino, D; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shukla, J; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Sopczak, André; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, A; Stone, H; Stoyanov, B; Strässner, A; Strauch, K; Sudhakar, K; Sultanov, G G; Sun, L Z; Susinno, G F; Suter, H; Swain, J D; Tang, X W; Tauscher, Ludwig; Taylor, L; Ting, Samuel C C; Ting, S M; Tonutti, M; Tonwar, S C; Tóth, J; Tully, C; Tuchscherer, H; Tung, K L; Uchida, Y; Ulbricht, J; Uwer, U; Valente, E; Van de Walle, R T; Vesztergombi, G; Vetlitskii, I; Viertel, Gert M; Vivargent, M; Völkert, R; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M; Wallraff, W; Wang, J C; Wang, X L; Wang, Z M; Weber, A; Wittgenstein, F; Wu, S X; Wynhoff, S; Xu, J; Xu, Z Z; Yang, B Z; Yang, C G; Yao, X Y; Ye, J B; Yeh, S C; You, J M; Zalite, A; Zalite, Yu; Zemp, P; Zeng, Y; Zhang, Z; Zhang, Z P; Zhou, B; Zhu, G Y; Zhu, R Y; Zichichi, Antonino; Ziegler, F

    1997-01-01

    The reaction $\\mathrm{e}^{+} \\mathrm{e}^{-} \\rightarrow \\mathrm{e}^{+} \\mathrm{e}^{-} \\gamma ^{*} \\gamma ^{*} \\rightarrow \\mathrm{e}^{+} \\mathrm{e}^{-} $ {\\sl hadrons} is analysed using data collected by the L3 detector during the LEP runs at $\\sqrt {s}$ = 130-140 GeV and $\\sqrt {s}$ = 161 GeV. The cross sections $\\sigma(\\mathrm{e}^{+} \\mathrm{e}^{-} \\rightarrow \\mathrm{e}^{+} \\mathrm{e}^{-} $ {\\sl hadrons}) and $\\sigma (\\gamma\\gamma \\rightarrow $ {\\sl hadrons}) are measured in the interval 5 $\\leq W_{\\gamma\\gamma} \\leq$ 75 GeV. The energy dependence of the $\\sigma (\\gamma\\gamma \\rightarrow $ {\\sl hadrons}) cross section is consistent with the universal Regge behaviour of total hadronic cross sections. %\\end{abstract}

  6. An examination of Indiana Early College High School students who attended Purdue University between 2006 and 2015

    OpenAIRE

    Kirkham, Lisa P

    2016-01-01

    Early College High Schools (ECHS) are an educational intervention designed to promote rigor in high school education along with increased post-secondary access and success for disadvantaged students. Based on evidence, the Early College High School program is effective at helping students who traditionally are not in college-bound tracks find their way into that path. ECHSs provide a comprehensive, rigorous high school experience allowing students to earn an associate’s degree along with the ...

  7. The e-ASTROGAM mission: Exploring the extreme Universe with gamma rays in the MeV – GeV range

    DEFF Research Database (Denmark)

    De Angelis, A.; Tatischeff, V.; Tavani, M.

    2017-01-01

    e-ASTROGAM (‘enhanced ASTROGAM’) is a breakthrough Observatory space mission, with a detector composed by a Silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV – the lower energy limit c...

  8. Gamma camera

    International Nuclear Information System (INIS)

    Tschunt, E.; Platz, W.; Baer, Ul; Heinz, L.

    1978-01-01

    A gamma camera has a plurality of exchangeable collimators, one of which is replaceably mounted in the ray inlet opening of the camera, while the others are placed on separate supports. Supports are swingably mounted upon a column one above the other

  9. Gamma camera

    International Nuclear Information System (INIS)

    Schlosser, P.A.; Steidley, J.W.

    1980-01-01

    The design of a collimation system for a gamma camera for use in nuclear medicine is described. When used with a 2-dimensional position sensitive radiation detector, the novel system can produce superior images than conventional cameras. The optimal thickness and positions of the collimators are derived mathematically. (U.K.)

  10. Wealth of the world's richest publicly traded companies per industry and per employee: Gamma, Log-normal and Pareto power-law as universal distributions?

    Science.gov (United States)

    Soriano-Hernández, P.; del Castillo-Mussot, M.; Campirán-Chávez, I.; Montemayor-Aldrete, J. A.

    2017-04-01

    Forbes Magazine published its list of leading or strongest publicly-traded two thousand companies in the world (G-2000) based on four independent metrics: sales or revenues, profits, assets and market value. Every one of these wealth metrics yields particular information on the corporate size or wealth size of each firm. The G-2000 cumulative probability wealth distribution per employee (per capita) for all four metrics exhibits a two-class structure: quasi-exponential in the lower part, and a Pareto power-law in the higher part. These two-class structure per capita distributions are qualitatively similar to income and wealth distributions in many countries of the world, but the fraction of firms per employee within the high-class Pareto is about 49% in sales per employee, and 33% after averaging on the four metrics, whereas in countries the fraction of rich agents in the Pareto zone is less than 10%. The quasi-exponential zone can be adjusted by Gamma or Log-normal distributions. On the other hand, Forbes classifies the G-2000 firms in 82 different industries or economic activities. Within each industry, the wealth distribution per employee also follows a two-class structure, but when the aggregate wealth of firms in each industry for the four metrics is divided by the total number of employees in that industry, then the 82 points of the aggregate wealth distribution by industry per employee can be well adjusted by quasi-exponential curves for the four metrics.

  11. Early initiation of sexual activity: a risk factor for sexually transmitted diseases, HIV infection, and unwanted pregnancy among university students in China

    Directory of Open Access Journals (Sweden)

    Ravari Shahrzad

    2009-04-01

    Full Text Available Abstract Background To explore any association between the timing of the initiation of sexual activity and sexual behaviors and risks among university students in China. Methods Data were derived from a cross-sectional study on sexual behavior among university students conducted in Ningbo municipality, China, at the end of 2003. Students completed a self-administered, structured questionnaire. Of 1981 sexually active male students, 1908 (96.3% completed the item for timing of the initiation of sexual activity and were included in bivariate trend analyses and multiple logistic regression analyses to compare the association between this timing and sexual behavior and risks. Results Male early sexual initiators had a significantly higher risk profile, including a significantly higher proportion reporting non-regular partners (i.e., casual or commercial partners, multiple partners, diagnosis with a sexually transmitted disease (STD, partner history of pregnancy, partner history of induced abortion, and less condom and oral contraceptive use, compared with late initiators. Multivariate analyses confirmed the increased likelihood of these risks in early initiators versus late initiators, other than partner type during the last year. Conclusion Our results showed that, compared to late initiators, people who initiated sexual activity early engaged in more risky behaviors that could lead to elevated risks of unwanted pregnancies and STDs or human immunodeficiency virus infection. Sex-education strategies should be focused on an earlier age, should include advice on delaying the age of first sexual activity, and should target young people who continue to take sexual risks.

  12. Mid-dose rate intracavitary therapy for uterine cervix cancer with a Selectron; An early experience of Osaka University

    Energy Technology Data Exchange (ETDEWEB)

    Teshima, Teruki; Inoue, Takehiro; Sasaki, Shigeru; Ohtani, Masatoshi; Kozuka, Takahiro; Inoue, Toshihiko; Ikeda, Hiroshi; Yamazaki, Hideya (Osaka Univ. (Japan). Faculty of Medicine); Murayama, Shigeyuki

    1993-05-01

    From May 1991 through September 1992, a total of 17 previously untreated patients with invasive uterine cervix cancer and with intact uterus were treated with mid-dose rate intracavitary therapy administered with a Selectron. Early primary tumor responses for all patients were complete. No acute or subacute radiation injury was observed except one patient with aplastic anemia who developed rectal ulcer. Two patients of Stage IIIb died from tumor because of local, paraaortic lymph node and distant metastases. Our early experience concluded that Selectron MDR can be used for cervix cancer patients as safely and effectively as our previously used high-dose rate machine. (author).

  13. Therapeutic efficacy of stereotactic radiotherapy with gamma knife on early-stage non-small-cell lung cancer and life quality of patients

    International Nuclear Information System (INIS)

    Ren Zhengting; Cui Di; Ren Ye; Dai Zhuojie; Su Xiaoming; Fan Jingjing; Shen Yulong; Ma Huizhen; Wang Zongye

    2012-01-01

    Objective: To evaluate the therapeutic efficacy of stereotactic body radiotherapy (SBRT) with gamma knife on stage Ⅰ-Ⅱ non-small-cell lung cancer (NSCLC)and the quality of life of the patients undergoing this therapy. Methods: Twenty NSCLC patients with the median age of 76, 10 at stage Ⅰ and 10 at stage Ⅱ who were unable or unwilling to undergo surgery were given SBRT with gamma knife at the doses of 3-6 Gy in 8-15 fractions,finished within 2 to 3 weeks. The prescription isodose line was 50%,the marginal dose was 39-56 Gy, the central dose was 78-112 Gy, and the total biologically effective dose was 51-83 Gy. The patients were observed after admission and followed up by chest CT 1, 3, 6, and 12 months after treatment until progressive disease or death. EORTC QLQ-LC43 questionnaire was used to investigate the changes in quality of life. Results: The 20 patients were followed up for 24 (12-46) months. At six months after the treatment,the overall response rate was 80%, and the complete response rate was 35%. The 1, 2 and 3-year local control rates were 100%, 95% and 95%, respectively. The 1, 2 and 3-year overall survival rates were 95%, 80% and 50% respectively; The 1, 2, and 3-year progression free survival rates were 85%, 64% and 33%, respectively. The failure rate was 20% and the rate of progress within the planning target volume was 5%. No acute toxicity at grade 3 and over occurred in any patient during the treatment. 15% of the patients developed grade 1-2 radiation pneumonia. Age, gender, pathologic index or not were weakly correlated with the overall survival. The emotional function was improved significantly after treatment (P<0.05), dyspnea and cough were improved at different degrees, however, not significantly. There were no significant changes in the physical function and symptoms, such as fatigue,lack of appetite, insomnia, etc. Conclusions: Significantly improving the motional function and maintaining the quality of life, SBRT with gamma knife

  14. Modeling Retention at a Large Public University: Can At-Risk Students Be Identified Early Enough to Treat?

    Science.gov (United States)

    Singell, Larry D.; Waddell, Glen R.

    2010-01-01

    We examine the extent to which readily available data at a large public university can be used to a priori identify at-risk students who may benefit from targeted retention efforts. Although it is possible to identify such students, there remains an inevitable tradeoff in any resource allocation between not treating the students who are likely to…

  15. Stakeholder perspectives on implementing a universal Lynch syndrome screening program: a qualitative study of early barriers and facilitators.

    Science.gov (United States)

    Schneider, Jennifer L; Davis, James; Kauffman, Tia L; Reiss, Jacob A; McGinley, Cheryl; Arnold, Kathleen; Zepp, Jamilyn; Gilmore, Marian; Muessig, Kristin R; Syngal, Sapna; Acheson, Louise; Wiesner, Georgia L; Peterson, Susan K; Goddard, Katrina A B

    2016-02-01

    Evidence-based guidelines recommend that all newly diagnosed colon cancer be screened for Lynch syndrome (LS), but best practices for implementing universal tumor screening have not been extensively studied. We interviewed a range of stakeholders in an integrated health-care system to identify initial factors that might promote or hinder the successful implementation of a universal LS screening program. We conducted interviews with health-plan leaders, managers, and staff. Interviews were audio-recorded and transcribed. Thematic analysis began with a grounded approach and was also guided by the Practical Robust Implementation and Sustainability Model (PRISM). We completed 14 interviews with leaders/managers and staff representing involved clinical and health-plan departments. Although stakeholders supported the concept of universal screening, they identified several internal (organizational) and external (environment) factors that promote or hinder implementation. Facilitating factors included perceived benefits of screening for patients and organization, collaboration between departments, and availability of organizational resources. Barriers were also identified, including: lack of awareness of guidelines, lack of guideline clarity, staffing and program "ownership" concerns, and cost uncertainties. Analysis also revealed nine important infrastructure-type considerations for successful implementation. We found that clinical, laboratory, and administrative departments supported universal tumor screening for LS. Requirements for successful implementation may include interdepartmental collaboration and communication, patient and provider/staff education, and significant infrastructure and resource support related to laboratory processing and systems for electronic ordering and tracking.

  16. A Personalised Needs-Led Group Approach to Induction: Perceptions of Early Academics in a University School of Education

    Science.gov (United States)

    Jarvis, Joy; Dickerson, Claire; Chivers, Leo; Collins, Chris; Lee, Libby; Levy, Roger; Solly, Dianne

    2012-01-01

    Members of staff joining a school of education often have extensive experience in practice but not in academia and the university setting may present a complex diversity of roles, ways of working, values and goals. Colleagues may face issues of understanding the organisational structure and culture, changing identities, and concerns about their…

  17. EARLY PRINTED CYRILLIC BOOKS OF THE MAKSYMOVYCH SCIENTIFIC LIBRARY OF THE TARAS SHEVCHENKO NATIONAL UNIVERSITY OF KYIV: THE NEW RESEARCH

    Directory of Open Access Journals (Sweden)

    Д. В. Лукін

    2017-10-01

    Full Text Available The article describes the latest research activities on early printed cyrillic books of the Maksymovych Scientific Library, being conducted in 2016-2017. The main attention is paid to the identification of early print editions and the publication of “provenientia”, marginalia, hand-written notes which reveal the origins and history of use of the certain printed documents. The several early Kievan prints are mentioned as well as personalities and locations which are connected with during their long history of use. The latest investigation of two copies of Didactic Gospel, printed in1606 inKrylos, is described. One of them, which was indentified recently, has its origin in TranscarpathianUkraine, while the second copy was donated to the church in Podillya region in 1624, and reappeared much later in private collection of Nikolai Maklakov (1805–1881. A brief description of the scientific project “The interaction of Ukrainian and Belarusian printed book traditions from the 16th till the beginning of the 19th century” is included. The article has its practical purpose in filling the gap in knowledge of certain parts of ukrainian early printed book heritage, which may be valuable to bibliogists and codicologists, dealing with cyrillic prints and manuscripts respectively.

  18. Big Five Personality Traits as Predictors of the Academic Success of University and College Students in Early Childhood Education

    Science.gov (United States)

    Smidt, Wilfried

    2015-01-01

    Academic success in early childhood teacher education is important because it provides a foundation for occupational development in terms of professional competence, the quality of educational practices, as well as career success. Consequently, identifying factors that can explain differences in academic success is an important research task.…

  19. Gamma Ray Burst Discoveries by the Swift Mission

    Science.gov (United States)

    Gehrels, Neil

    2006-01-01

    Gamma-ray bursts are among the most fascinating occurrences in the cosmos. They are thought to be the birth cries of black holes throughout the universe. The NASA swift mission is an innovative new multiwavelength observatory designed to determine the origin of bursts and use them to probe the early Universe. Swift is now in orbit since November 20, 2004 and all hardware is performing well. A new-technology wide-field gamma-ray camera is detecting a hundred bursts per year. sensitive narrow-field X-ray and uv/optical telescopes, built in collaboration with UK and Italian partners, are pointed at the burst location in 50-100 sec by an autonomously controlled "swift" spacecraft. For each burst, arcsec positions are determined and optical/UV/X-ray/gamma-ray spectrophotometry performed. Information is also rapidly sent to the ground to a team of more than 50 observers at telescopes around the world. The first year of findings from the mission will be presented. There has been a break-through in the longstanding mystery of short GRBs; they appear to be caused by merging neutron stars. High redshift bursts have been detected leading to a better understanding of star formation rates and distant galaxy environments. GRBs have been found with giant X-ray flares occurring in their afterglow.

  20. Gamma Ray Burst Discoveries by the Swift Mission

    Science.gov (United States)

    Gehrels, Neil

    2006-04-01

    Gamma-ray bursts are among the most fascinating occurrences in the cosmos. They are thought to be the birth cries of black holes throughout the universe. The NASA Swift mission is an innovative new multiwavelength observatory designed to determine the origin of bursts and use them to probe the early Universe. Swift is now in orbit since November 20, 2004 and all hardware is performing well. A new-technology wide-field gamma-ray camera is detecting a hundred bursts per year. Sensitive narrow-field X-ray and UV/optical telescopes, built in collaboration with UK and Italian partners, are pointed at the burst location in 50-100 sec by an autonomously controlled ``swift'' spacecraft. For each burst, arcsec positions are determined and optical/UV/X-ray/gamma-ray spectrophotometry performed. Information is also rapidly sent to the ground to a team of more than 50 observers at telescopes around the world. The first year of findings from the mission will be presented. There has been a break-through in the long-standing mystery of short GRBs; they appear to be caused by merging neutron stars. High redshift bursts have been detected leading to a better understanding of star formation rates and distant galaxy environments. GRBs have been found with giant X-ray flares occurring in their afterglow.

  1. ON THE RELATIVE ABUNDANCE OF LiH AND LiH+ MOLECULES IN THE EARLY UNIVERSE: NEW RESULTS FROM QUANTUM REACTIONS

    International Nuclear Information System (INIS)

    Bovino, Stefano; Tacconi, Mario; Gianturco, Franco A.; Galli, Daniele; Palla, Francesco

    2011-01-01

    The relative efficiencies of the chemical pathways that can lead to the destruction of LiH and LiH + molecules, conjectured to be present in the primordial gas and to control molecular cooling processes in the gravitational collapse of the post-recombination era, are revisited by using accurate quantum calculations for the several reactions involved. The new rates are employed to survey the behavior of the relative abundance of these molecules at redshifts of interest for early universe conditions. We find significant differences with respect to previous calculations, the present ones yielding LiH abundances higher than LiH + at all redshifts.

  2. Development of the 2nd generation z(Redshift) and early universe spectrometer & the study of far-IR fine structure emission in high-z galaxies

    Science.gov (United States)

    Ferkinhoff, Carl

    The 2nd generation z (Redshift) and Early Universe Spectrometer (ZEUS-2), is a long-slit echelle-grating spectrometer (R~1000) for observations at submillimeter wavelengths from 200 to 850 microm. Its design is optimized for the detection of redshifted far-infrared spectral lines from galaxies in the early universe. Combining exquisite sensitivity, broad wavelength coverage, and large (˜2.5%) instantaneous bandwidth, ZEUS-2 is uniquely suited for studying galaxies between z˜0.2 and 5---spanning the peaks in both the star formation rate and number of AGN in the universe. ZEUS-2 saw first light at the Caltech Submillimeter Observatory (CSO) in the Spring of 2012 and was commissioned on the Atacama Pathfinder Experiment (APEX) in November 2012. Here we detail the design and performance of ZEUS-2, first however we discuss important science results that are examples of the science enabled by ZEUS-2. Using the first generation z (Redshift) and Early Universe Spectrometer (ZEUS-1) we made the first high-z detections of the [NII] 122 microm and [OIII] 88 microm lines. We detect these lines from starburst galaxies between z ˜2.5 and 4 demonstrating the utility of these lines for characterizing the properties of early galaxies. Specifically we are able to determine the most massive star still on the main sequence, the number of those stars and a lower limit on the mass of ionized gas in the source. Next we present ZEUS-2's first science result. Using ZEUS-2 on APEX we have detected the [CII] 158 microm line from the z = 1.78 galaxy H-ATLAS J091043.1-000322 with a line flux of (6.44 +/- 0.42) ˜ 10-18 W m-2. Combined with its far-infrared luminosity and a new Herschel-PACS detection of the [OI] 63 microm line we are able to conclude that H-ATLAS J091043.1-000322 is a high redshift analogue of a local ultra-luminous infrared galaxy, i.e. it is likely the site of a compact starburst due to a major merger. This detection, combined with the ZEUS-1 observations of the [NII

  3. Evaluation of the effect of early clinical exposure on professional attitude of dental students of Shahid Sadoughi University of Medical Sciences in 2011-2012

    Directory of Open Access Journals (Sweden)

    H. Aghili

    2013-06-01

    Full Text Available Introduction : Learning dentistry could have many tension and anxieties like encountering to a strange clinical environment. Early clinical exposure (ECE is supposed to control these stresses. ECE program is an increasingly widespread component of educational curriculum. This study aims to determine the effect of early clinical exposure on the attitude of dental students’ towards dental education and profession. Methods: An analytic study was performed on all 72 dental students studying basic science at Faculty of Dentistry of Shahid Sadoughi University of Medical Sciences consisted of a short term course of introduction to clinical environment in academic year of 2011-2012. Every 12 students attended in an one day ECE course from 8 AM to 1 PM. Students ' attitude towards dental profession and education were assessed by a questionnaire included 25 items before and after the course .For data analysis descriptive paired-t-test was used. Results: All students completed the questionnaires. Students' attitude towards dental education and profession was evaluated. Mean score of students' attitude before and after exposure to clinical environment were 94.6 and 100.5 respectively .Significant differences were found in the students' attitude before and after the course (P=0.001 Conclusion: Based on the results of this study, we found a positive effect of early clinical exposure on attitudes of first and second year dental students. Demographic variations had an effect on the students' attitude .Therefore we suggest that early clinical exposure should be added to educational curriculum of dental students.

  4. Gamma camera

    International Nuclear Information System (INIS)

    Reiss, K.H.; Kotschak, O.; Conrad, B.

    1976-01-01

    A gamma camera with a simplified setup as compared with the state of engineering is described permitting, apart from good localization, also energy discrimination. Behind the usual vacuum image amplifier a multiwire proportional chamber filled with trifluorine bromium methane is connected in series. Localizing of the signals is achieved by a delay line, energy determination by means of a pulse height discriminator. With the aid of drawings and circuit diagrams, the setup and mode of operation are explained. (ORU) [de

  5. Gamma irradiator

    International Nuclear Information System (INIS)

    Simonet, G.

    1986-09-01

    Fiability of devices set around reactors depends on material resistance under irradiation noticeably joints, insulators, which belongs to composition of technical, safety or physical incasurement devices. The irradiated fuel elements, during their desactivation in a pool, are an interesting gamma irradiation device to simulate damages created in a nuclear environment. The existing facility at Osiris allows to generate an homogeneous rate dose in an important volume. The control of the element distances to irradiation box allows to control this dose rate [fr

  6. Gamma teletopography

    International Nuclear Information System (INIS)

    Simonet, G.

    1987-06-01

    The mapping of gamma sources radiation emission in a nuclear plant is an important safety point. A remote gamma ray mapping process was developed in SPS/CEA/SACLAY. It uses the ''pinhole camera'' principle, precursor of photography. It mainly consists of a radiation proof box, with a small orifice, containing sensitive emulsions at the opposite. A first conventional photographic type emulsion photographs the area. A second photographic emulsion shows up the gamma radiations. The superim position of the two shots gives immediate informations of the precise location of each source of radiation in the observed area. To make easier the presentation and to improve the accuracy of the results for radiation levels mapping, the obtained films are digitally processed. The processing assigns a colours scale to the various levels of observed radiations. Taking account physical data and standard parameters, it gets possible to estimate the dose rate. The device is portable. Its compactness and fully independent nature make it suitable for use anywhere. It can be adapted to a remote automatic handling system, robot... so as to avoid all operator exposure when the local dose rate is too high [fr

  7. On the creation of scalar particles in an early stage of the Friedmann closed-universe II

    International Nuclear Information System (INIS)

    Ishihara, Hideki; Nariai, Hidekazu.

    1982-09-01

    As a sequel to the previous work, the creation of scalar particles in an expanding closed-universe is studied in terms of our Feynman propagator and of fixing a pair of particle states. It is shown that the obtained spectral law for the creation of particles is identical with the previous one derived in terms of the vacuum expectation value at an initial time eta = eta sub(i) of the number operator at late time eta = eta sub(f). (author)

  8. Activation of PPAR{gamma} by Human Cytomegalovirus for de novo Replication Impairs Migration and Invasiveness of Cytotrophoblast from Early Placenta

    DEFF Research Database (Denmark)

    Rauwel, Benjamin; Mariamé, Bernard; Martin, Hélène

    2010-01-01

    , as assessed by using well-established in vitro models of invasive trophoblast i.e. primary cultures of EVCT isolated from first trimester placentas and the EVCT-derived cell line HIPEC. Our data provide new clues to explain how early infection during pregnancy could impair implantation, placentation...... and chromatin immunoprecipitation assays. Due to the key role of PPARgamma in placentation and its specific trophoblast expression within the human placenta, we then provided evidence that by activating PPARgamma human cytomegalovirus dramatically impaired early human trophoblast migration and invasiveness...

  9. Gravitino in the early Universe. A model of extra-dimension and a model of dark matter

    International Nuclear Information System (INIS)

    Gherson, D.

    2007-10-01

    This work can be related to the Horava-Witten M-theory in which the Universe could appear 5 dimensional at a stage of its evolution but also to theories of Baryogenesis through Lepto-genesis which imply high reheating temperatures after Inflation. The studied cosmological model is within the framework of a 5 dimensional supergravity with the extra-dimension compactified on an orbifold circle, where the matter and gauge field are located on one of the two branes localised at the orbifold fixed points and where the supergravity fields can propagate in the whole spatial dimensions. In the model, the Dark matter is made of neutralino which is supposed to be the lightest supersymmetric particle. We have shown that there are curves of constraints between the size of the extra-dimension and the reheating temperature of the Universe after Inflation. The constraints come from the measurements of the amount of Dark matter in the Universe and from the model of the Big Bang Nucleosynthesis of light elements. (author)

  10. Gamma surgery for hemangiopericytomas

    International Nuclear Information System (INIS)

    Payne, B.R.; Prasad, D.; Steiner, M.; Steiner, L.

    2000-01-01

    A retrospective analysis of a consecutive series of 12 patients with 15 intracranial hemangiopericytomas treated at the University of Virginia using gamma surgery is presented. Clinical and radiographic follow up of 3 to 56 months is available for 10 patients with 12 tumors. There was one tumor present at the time of initial gamma surgery in each patient. Two new tumors occurred in patients previously treated. Nine of the tumors decreased in volume and three remained stable. Four of the nine tumors that shrank later progressed at an average of 22 months after treatment. Of the tumors that decreased in volume and have not progressed, the response has been for an average of 11 months. The follow-up for two tumors that remained unchanged was 10 and 34 months (average 22 months). A third tumor was unchanged at 42 months but the patient died of new disease adjacent to the treated area in the anterior skull base. There were no complications and the quality of life following the procedure was maintained or improved in every case. Gamma surgery is effective in palliating the patients by decreasing tumor volume and delaying recurrence. (author)

  11. Dose calculation in biological samples in a mixed neutron-gamma field at the TRIGA reactor of the University of Mainz

    DEFF Research Database (Denmark)

    Schmitz, T.; Blaickner, M.; Schütz, C.

    2010-01-01

    and pin-diodes. Material and methods. When L-α-alanine is irradiated with ionizing radiation, it forms a stable radical which can be detected by electron spin resonance (ESR) spectroscopy. The value of the ESR signal correlates to the amount of absorbed dose. The dose for each pellet is calculated using......To establish Boron Neutron Capture Therapy (BNCT) for non-resectable liver metastases and for in vitro experiments at the TRIGA Mark II reactor at the University of Mainz, Germany, it is necessary to have a reliable dose monitoring system. The in vitro experiments are used to determine the relative......-calculations for mixed radiation fields and the Hansen & Olsen alanine detector response model. With the acquired data about the background dose and charged particle spectrum, and with the acquired information of the neutron flux, we are capable of calculating the dose to the tissue. Conclusion. Monte Carlo simulation...

  12. Integral -tracking extreme radiation across the Universe

    Science.gov (United States)

    2002-10-01

    costs, the design for the service module was reused from ESA’s XMM-Newton satellite. Note to editors: historical perspective on gamma-ray astronomy Scientists have placed small gamma-ray detectors on satellites since the early 1960s. However, the most extraordinary discovery came in the late 1960s from a series of military satellites designed to monitor the ban on nuclear bombs being tested on Earth. These satellites detected the appropriately named gamma-ray bursts, which explode without warning about once a day, from random directions in the sky. In 1972, the NASA probe SAS-2 confirmed that the Universe is bathed in a perpetual shower of gamma rays. In 1975, ESA launched the gamma-ray satellite COS-B, that worked until being switched off in 1982. COS-B produced the first map of the gamma-ray sky and identified a number of bright gamma ray sources. It was followed by the Russian-French mission GRANAT, in 1989-1998, and NASA’s Compton Gamma-ray Observatory (CGRO), in 1991-2000. The CGRO satellite greatly increased our understanding of gamma-ray astronomy. Soon we can expect Integral to dazzle the world with the next leap in technology.

  13. "Big Bang" as a result result of the curvature-driven first-order phase transition in the early cold Universe

    Science.gov (United States)

    Pashitskii, E. A.; Pentegov, V. I.

    We suggest that the "Big Bang" may be a result of the first-order phase transition driven by changing scalar curvature of the 4D space-time in the expanding cold Universe, filled with nonlinear scalar field φ and neutral matter with equation of state p = vɛ (where p and ɛ are pressure and energy density of matter). We consider a Lagrangian for scalar field in curved space-time with nonlinearity φ, which along with the quadratic term -ΣR|φ|2 (where Σ is interaction constant and R is scalar curvature) contains a term ΣR(φ +φ+) linear in φ. Due to this term the condition for the extrema of the potential energy of the scalar field is given by a cubic equation. Provided v > 1/3 the scalar curvature R = [κ(3v-1)ɛ - 4Γ (where κ and Γ are Einstein's gravitational and cosmological constants) decreases along with decreasing " in the process of the Universe's expansion, and at some critical value Rc < 0 a first-order phase transition occurs, driven by an "external field" parameter proportional to R. Given certain conditions the critical radius of the early Universe at the point of the first-order phase transition may reach arbitrary large values, so this scenario of unrestricted "inflation" of the Universe may be called "hyperinflation". Beyond the point of phase transition the system is rolling down into the potential minimum releasing the potential energy of scalar field with subsequent powerful heating of the Universe playing the role of "Big Bang".

  14. Studies of neutrino asymmetries generated by ordinary-sterile neutrino oscillations in the early Universe and implications for big bang nucleosynthesis bounds

    Energy Technology Data Exchange (ETDEWEB)

    Foot, R.; Volkas, R.R. [Research Centre for High Energy Physics, School of Physics, University of Melbourne, Parkville, 3052 (Australia)

    1997-04-01

    Ordinary-sterile neutrino oscillations can generate a significant lepton number asymmetry in the early Universe. We study this phenomenon in detail. We show that the dynamics of ordinary-sterile neutrino oscillations in the early Universe can be approximately described by a single integrodifferential equation which we derive from both the density matrix and Hamiltonian formalisms. This equation reduces to a relatively simple ordinary first-order differential equation if the system is sufficiently smooth (static limit). We study the conditions for which the static limit is an acceptable approximation. We also study the effect of the thermal distribution of neutrino momenta on the generation of lepton number. We apply these results to show that it is possible to evade (by many orders of magnitude) the big bang nucleosynthesis (BBN) bounds on the mixing parameters {delta}m{sup 2} and sin{sup 2}2{theta}{sub 0} describing ordinary-sterile neutrino oscillations. We show that the large angle or maximal vacuum oscillation solution to the solar neutrino problem does not significantly modify BBN for most of the parameter space of interest, provided that the {tau} and/or {mu} neutrinos have masses greater than about 1 eV. We also show that the large angle or maximal ordinary-sterile neutrino oscillation solution to the atmospheric neutrino anomaly does not significantly modify BBN for a range of parameters. {copyright} {ital 1997} {ital The American Physical Society}

  15. Statistical mechanics and the description of the early universe II. Principle of detailed balance and primordial 4He formation

    DEFF Research Database (Denmark)

    Pessah, Martin Elias; F. Torres, Diego

    2001-01-01

    If the universe is slightly non-extensive, and the distribution functions are not exactly given by those of Boltzmann-Gibbs, the primordial production of light elements will be non-trivially modified. In particular, the principle of detailed balance (PDB), of fundamental importance in the standard...... the formation of Helium and Deuterium, and study the kind of deviation one could expect from the standard regime. The correction to the capture time, the moment in which Deuterium can no longer be substantially photo-disintegrated, is also presented. This allows us to take into account the process of the free...

  16. Gamma teletopography

    International Nuclear Information System (INIS)

    Simonet, G.

    1986-09-01

    To set the gamma activity cartography is an important element of safety in numerous cases: intervention in hot cell, search of a radioactive source, examination of radioactive waste circuit followed by a reprocessing definition of decontamination and decommissioning processes and for all other accidents. The device presented here is like a ''black box'' with an aperture and an emulsion photosensitive to the opposite; a classical film takes photography of the place; a X-ray type emulsion gives a spot more or less contrasted and extensive corresponding to each source. Images can be processed with a microprocessor [fr

  17. Early IFN-gamma production after YF 17D vaccine virus immunization in mice and its association with adaptive immune responses.

    Directory of Open Access Journals (Sweden)

    Patrícia C C Neves

    Full Text Available Yellow Fever vaccine is one of the most efficacious human vaccines ever made. The vaccine (YF 17D virus induces polyvalent immune responses, with a mixed TH1/TH2 CD4(+ cell profile, which results in robust T CD8(+ responses and high titers of neutralizing antibody. In recent years, it has been suggested that early events after yellow fever vaccination are crucial to the development of adequate acquired immunity. We have previously shown that primary immunization of humans and monkeys with YF 17D virus vaccine resulted in the early synthesis of IFN-γ. Herein we have demonstrated, for the first time that early IFN-γ production after yellow fever vaccination is a feature also of murine infection and is much more pronounced in the C57BL/6 strain compared to the BALB/c strain. Likewise, in C57BL/6 strain, we have observed the highest CD8(+ T cells responses as well as higher titers of neutralizing antibodies and total anti-YF IgG. Regardless of this intense IFN-γ response in mice, it was not possible to see higher titers of IgG2a in relation to IgG1 in both mice lineages. However, IgG2a titers were positively correlated to neutralizing antibodies levels, pointing to an important role of IFN-γ in eliciting high quality responses against YF 17D, therefore influencing the immunogenicity of this vaccine.

  18. Early-stage bilateral breast cancer treated with breast-conserving surgery and definitive irradiation: the university of Pennsylvania experience

    International Nuclear Information System (INIS)

    Fung, Man C.; Schultz, Delray J.; Solin, Lawrence J.

    1997-01-01

    Purpose: To determine whether patients with early-stage bilateral breast cancer can be treated with definitive irradiation following breast-conserving surgery with acceptable survival, local control, complications, and cosmesis. Methods and Materials: During the period 1977-1992, 55 women with Stage 0, I, or II concurrent (n = 12) or sequential (n = 43) bilateral breast cancer were treated with definitive irradiation following breast-conserving surgery. The records of these 55 patients with 110 treated breasts were reviewed for tumor size, histology, pathologic axillary lymph node status, first and overall site(s) of failure, and adjuvant chemotherapy or hormonal therapy. Curves for survival, local control, and regional control were determined. Cosmetic outcome, complication rates, and matching technique were analyzed. The median total radiation dose delivered was 64 Gy (range 42-72) using tangential whole-breast irradiation followed by an electron or iridium implant boost. The tangential fields were matched with no overlap in 40 patients (73%); there was overlap on skin of up to 4 cm in 14 patients (25%); and the matching technique was unknown in 1 patient (2%). The median follow-up for the 12 women with concurrent bilateral breast cancer was 4.0 years. The median follow-up for the other 43 women with sequential cancer was 9.3 and 4.9 years, respectively, after the first and second cancers. Results: For the overall group of 55 patients, the 5- and 10-year overall survival rates were 96% and 94%, respectively, after treatment of the first cancer, and 96% and 92%, respectively, after treatment of the second cancer. The 5- and 10-year actuarial relapse-free survival rates were 90% and 75%, respectively, after treatment of the first cancer, and 83% and 72%, respectively, after treatment of the second cancer. For the 110 treated breast cancers, the 5- and 10-year actuarial local failure rates were 5% and 15%, respectively. Complication rates were: 28% breast edema, 8

  19. Gamma knife

    International Nuclear Information System (INIS)

    Kawamoto, Shunsuke; Takakura, Kintomo

    1991-01-01

    As to the gamma knife which is the radiation surgery device developed in Sweden a quarter century ago, its principle, structure, treatment techniques, already established clinical effect and the problems being left for hereafter are described. This treatment means supplements the operation under microscopes, and at present it takes the important position in neurosurgery, but hereafter, by the interdisciplinary cooperation of neurosurgery and clinical radiobiology, the more development can be expected. The method of irradiating the radiation of high dose selectively to a target region and breaking its tissue is called radiosurgery, and the device developed for this purpose is the gamma knife. First, it was applied to functional diseases, but good results were obtained by its application to auditory nerve and brain blood vessels, and it establishes the position as the safe treatment method of the morbid state in the deep part of brains, which is difficult to reach by operation. Accompanying the recent progress of the operation of skull base part, attention is paid to its application to various tumors in skull base. On the other hand, the radiosurgery combining a cyclotron or a linear accelerator with stereotaxic brain surgery is actively tried mainly to the deformation of brain blood vessels. (K.I.)

  20. Our Universe

    Science.gov (United States)

    Stern, Alan

    2001-03-01

    The Universe in which we live is unimaginably vast and ancient, with countless star systems, galaxies, and extraordinary phenomena such as black holes, dark matter, and gamma ray bursts. What phenomena remain mysteries, even to seasoned scientists? Our Universe is a fascinating collection of essays by some of the world's foremost astrophysicists. Some are theorists, some computational modelers, some observers, but all offer their insights into the most cutting-edge, difficult, and curious aspects of astrophysics. Compiled, the essays describe more than the latest techniques and findings. Each of the ten contributors offers a more personal perspective on their work, revealing what motivates them and how their careers and lives have been shaped by their desire to understand our universe. S. Alan Stern is Director of the Department of Space Studies at Southwest Research Institute in Boulder, Colorado. He is a planetary scientist and astrophysicist with both observational and theoretical interests. Stern is an avid pilot and a principal investigator in NASA's planetary research program, and he was selected to be a NASA space shuttle mission specialist finalist. He is the author of more than 100 papers and popular articles. His most recent book is Pluto & Charon (Wiley, 1997). Contributors: Dr. John Huchra, Harvard University Dr. Esther Hu, University of Hawaii, Honolulu Dr. John Mather, NASA Goddard Space Flight Center Dr. Nick Gnedin, University of Colorado, Boulder Dr. Doug Richstone, University of Michigan, Ann Arbor Dr. Bohdan Paczynski, Princeton University, NJ Dr. Megan Donahue, Space Telescope Science Institute, Baltimore, MD Dr. Jerry Ostriker, Princeton University, New Jersey G. Bothun, University of Oregon, Eugene

  1. Early-Stage Investigators and Institutional Interface: Importance of Organization in the Mentoring Culture of Today's Universities.

    Science.gov (United States)

    Manson, Spero M

    2016-09-01

    Mentors have an active role in teaching mentees to scan their academic environments for the resources to advance their research careers, to assess the gaps between what's available and needed to succeed, and to develop strategies to fill these gaps. Yet achieving instrumentality is a necessary, but insufficient condition by which to accomplish the desired endpoints. Mentors and mentees must recognize that the organizations to which they belong are cultural in nature: characterized by vision, values, norms, systems, symbols, language, assumptions, beliefs, and habits. Understanding the collective behaviors and assumptions of peers and leaders in terms of the shared perceptions, thoughts, and feelings of organizational membership is essential to success. Institutions, in turn, must examine the extent to which they offer action possibilities: opportunities that promote the developmental trajectories of early stage investigators-in-training. Lack of awareness of the possible dissonance of this reality adversely affects many young faculty members.

  2. Exposure of mother rats to chronic unpredictable stress before pregnancy alters the metabolism of gamma-aminobutyric acid and glutamate in the right hippocampus of offspring in early adolescence in a sexually dimorphic manner.

    Science.gov (United States)

    Huang, Yuejun; Shen, Zhiwei; Hu, Liu; Xia, Fang; Li, Yuewa; Zhuang, Jingwen; Chen, Peishan; Huang, Qingjun

    2016-12-30

    There is increasing evidence that mothers' exposure to stress before or during pregnancy is linked to an incidence of psychiatric disorders in offspring. However, a few studies have estimated the role of sex in the detrimental effects of pre-gestational stress on the offspring rats at early adolescence. Sex differences regarding the metabolism of gamma-aminobutyric acid and glutamate in the right hippocampus were investigated by MRS when the offspring rats reached 30 days. Additionally, the impact of pre-gestational stress exposed on an additional short-term acute stressor, such as forced swim, was examined in the male and female offspring rats. Our findings showed female offspring rats were more vulnerable to stressful conditions for either pre-gestational stress or acute stress in early adolescence, and had decreased GABA/Cr+PCr and Glu/Cr+PCr in the right hippocampus. Interestingly, in response to forced swim, male offspring rats whose mothers were exposed to pre-gestational stress were more affected by the short-term acute stressor and this was manifested by change of Glu/GABA and Glu/Gln in the right hippocampus. These data indicated that although female offspring rats were more vulnerable to pre-gestational stress from their mothers than males, in response to an additional acute stressor they showed better response. Therefore, both sexually dimorphic manner and combination of stressful procedures should be carefully considered in the study of stress-related psychiatric disorders in early adolescence. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Investigations on early reactions of lymphocyte proteins on gamma irradiation of human blood and their dose dependence. Preconditions for the development of an individual radiobiological dosimeter

    International Nuclear Information System (INIS)

    Turtoi, Andrei

    2007-01-01

    The present thesis is concerned with the issues involved in obtaining reliable experimental data permitting a retrospective assessment of radiation-induced doses at the time of application or contamination. In order to provide prompt medical treatment of those injured in accidents with ionizing radiation, biological procedures that can be implemented swiftly and at an early stage are required both to determine the radiation dose originally received as well as to assess the course of the dosedependent biological reactions on the basis of individual sensitivity to radiation. To this end, in the present thesis the lymphocyte proteins (phosphoproteins and total proteins) in blood taken from test subjects who had been exposed to γ-radiation (applied dose: 0-4 Gy) were analysed just 15 minutes after completing irradiation by means of 2D gel electrophoresis. Only those early-response proteins (ERPROs) that displayed a significant radiation-induced change were identified by nano-HPLC-MS/MS. For validation purposes, the dose-dependent gene expression of some of these proteins was determined by RT-qPCR. The following ERPROs displayed pronounced early reactions in the form of changes of concentration in comparison to unirradiated control samples: talin-1, talin-2, β-actin, mutant β-actin, peroxin-1 and also the phosphoproteins annexin-A6, MHCbinding protein-2, zyxin-2, interleukin-17E and phosphoglycerate kinase-1. The majority of the lymphocyte ERPROs represent proteins responsible for changes to the cytoskeleton, proliferation and cell cycle, modulation of immunoreactions as well as protein degradation and energy production. Other cellular processes may not have been determined due to the sensitivity restrictions of the 2DPAGE and MS methods, but cannot be excluded. Gene expression studies revealed that a combination of methods, comprising RT-qPCR and 2D-PAGE as well as DNA microarray and Western blot, may in future be able to overcome these restrictions. The slopes of

  4. Collaborative, Early-undergraduate-focused REU Programs at Savannah State University have been Vital to Growing a Demographically Diverse Ocean Science Community

    Science.gov (United States)

    Gilligan, M. R.; Cox, T. M.; Hintz, C. J.

    2011-12-01

    Formal support for undergraduates to participate in marine/ocean science research at Savannah State University (SSU), a historically-Black unit of the University System of Georgia, began in 1989 with funding from the National Science Foundation for an unsolicited proposal (OCE-8919102, 34,935). Today SSU, which has offered B.S degrees since 1979 and M.S. degrees since 2001 in Marine Sciences, is making major contributions nationally to demographic diversity in ocean sciences. 33% of Master's degrees in marine/ocean sciences earned by African Americans in the U.S. from 2004-2007 were earned at SSU. 10% of African American Master's and Doctoral students in marine/ ocean sciences in 2007 were either enrolled in the Master's program at SSU or were former SSU students enrolled in Doctoral programs elsewhere. Collaborative REU programs that focus on early (freshman and sophomore) undergraduate students have been a consistent and vital part of that success. In the most recent iteration of our summer REU program we used six of the best practices outlined in the literature to increase success and retention of underrepresented minority students in STEM fields: early intervention, strong mentoring, research experience, career counseling, financial support, workshops and seminars. The early intervention with strong mentoring has proven successful in several metrics: retention in STEM majors (96%), progression to graduate school (50%), and continuation to later research experiences (75%). Research mentors include faculty at staff at SSU, the Skidaway Institute of Oceanography, Gray's Reef National Marine Sanctuary and Georgia Tech-Savannah. Formal collaborative and cooperative agreements, externally-funded grants, and contracts in support of student research training have proven to be critical in providing resources for growth and improvement marine science curricular options at the University. Since 1981 the program has had four formal partnerships and 36 funded grant awards

  5. Gone with the heat: a fundamental constraint on the imaging of dust and molecular gas in the early Universe.

    Science.gov (United States)

    Zhang, Zhi-Yu; Papadopoulos, Padelis P; Ivison, R J; Galametz, Maud; Smith, M W L; Xilouris, Emmanuel M

    2016-06-01

    Images of dust continuum and carbon monoxide (CO) line emission are powerful tools for deducing structural characteristics of galaxies, such as disc sizes, H2 gas velocity fields and enclosed H2 and dynamical masses. We report on a fundamental constraint set by the cosmic microwave background (CMB) on the observed structural and dynamical characteristics of galaxies, as deduced from dust continuum and CO-line imaging at high redshifts. As the CMB temperature rises in the distant Universe, the ensuing thermal equilibrium between the CMB and the cold dust and H2 gas progressively erases all spatial and spectral contrasts between their brightness distributions and the CMB. For high-redshift galaxies, this strongly biases the recoverable H2 gas and dust mass distributions, scale lengths, gas velocity fields and dynamical mass estimates. This limitation is unique to millimetre/submillimetre wavelengths and unlike its known effect on the global dust continuum and molecular line emission of galaxies, it cannot be addressed simply. We nevertheless identify a unique signature of CMB-affected continuum brightness distributions, namely an increasing rather than diminishing contrast between such brightness distributions and the CMB when the cold dust in distant galaxies is imaged at frequencies beyond the Raleigh-Jeans limit. For the molecular gas tracers, the same effect makes the atomic carbon lines maintain a larger contrast than the CO lines against the CMB.

  6. COMPACT STELLAR BINARY ASSEMBLY IN THE FIRST NUCLEAR STAR CLUSTERS AND r-PROCESS SYNTHESIS IN THE EARLY UNIVERSE

    International Nuclear Information System (INIS)

    Ramirez-Ruiz, Enrico; MacLeod, Morgan; Trenti, Michele; Roberts, Luke F.; Lee, William H.; Saladino-Rosas, Martha I.

    2015-01-01

    Investigations of elemental abundances in the ancient and most metal deficient stars are extremely important because they serve as tests of variable nucleosynthesis pathways and can provide critical inferences of the type of stars that lived and died before them. The presence of r-process elements in a handful of carbon-enhanced metal-poor (CEMP-r) stars, which are assumed to be closely connected to the chemical yield from the first stars, is hard to reconcile with standard neutron star mergers. Here we show that the production rate of dynamically assembled compact binaries in high-z nuclear star clusters can attain a sufficient high value to be a potential viable source of heavy r-process material in CEMP-r stars. The predicted frequency of such events in the early Galaxy, much lower than the frequency of Type II supernovae but with significantly higher mass ejected per event, can naturally lead to a high level of scatter of Eu as observed in CEMP-r stars

  7. COMPACT STELLAR BINARY ASSEMBLY IN THE FIRST NUCLEAR STAR CLUSTERS AND r-PROCESS SYNTHESIS IN THE EARLY UNIVERSE

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez-Ruiz, Enrico; MacLeod, Morgan [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Trenti, Michele [Kavli Institute for Cosmology and Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Roberts, Luke F. [TAPIR, California Institute of Technology, Pasadena, California 91125 (United States); Lee, William H.; Saladino-Rosas, Martha I. [Instituto de Astronomía, Universidad Nacional Autónoma de México, México DF 04510, México (Mexico)

    2015-04-01

    Investigations of elemental abundances in the ancient and most metal deficient stars are extremely important because they serve as tests of variable nucleosynthesis pathways and can provide critical inferences of the type of stars that lived and died before them. The presence of r-process elements in a handful of carbon-enhanced metal-poor (CEMP-r) stars, which are assumed to be closely connected to the chemical yield from the first stars, is hard to reconcile with standard neutron star mergers. Here we show that the production rate of dynamically assembled compact binaries in high-z nuclear star clusters can attain a sufficient high value to be a potential viable source of heavy r-process material in CEMP-r stars. The predicted frequency of such events in the early Galaxy, much lower than the frequency of Type II supernovae but with significantly higher mass ejected per event, can naturally lead to a high level of scatter of Eu as observed in CEMP-r stars.

  8. Gamma camera

    International Nuclear Information System (INIS)

    Tschunt, E.; Platz, W.; Baer, U.; Heinz, L.

    1978-01-01

    A gamma camera has a plurality of exchangeable collimators, one of which is mounted in the ray inlet opening of the camera, while the others are placed on separate supports. The supports are swingably mounted upon a column one above the other through about 90 0 to a collimator exchange position. Each of the separate supports is swingable to a vertically aligned position, with limiting of the swinging movement and positioning of the support at the desired exchange position. The collimators are carried on the supports by means of a series of vertically disposed coil springs. Projections on the camera are movable from above into grooves of the collimator at the exchange position, whereupon the collimator is turned so that it is securely prevented from falling out of the camera head

  9. The Process of Preparing for The Job of an Early Education Teacher as Perceived by Students of the University of Warmia and Mazury In Olsztyn

    Directory of Open Access Journals (Sweden)

    Małgorzata Suświłło

    2015-12-01

    Full Text Available This paper addresses the issue of preparing students for the job of early education teacher. The first part focuses both on the teacher training as carried out in various European countries according to the Eurydice report prepared for the European Commission in 2013, and on the notion, presented by Sylvia Yee Fan Tang, of the dynamics of students’ turning to teachers. The second part demonstrates the author’s own research. The participants were students of the Social Science Faculty at the University of Warmia and Mazury in Olsztyn. The interpretation of the results is informed by Robert Kwaśnica’s two rationalities theory. The results demonstrate both the students’ attitude of entitlement and their adaptive thinking (rationality as far as the preparing for the job is concerned. On the other hand, the results also show the participants’ emancipation rationality, which manifests itself in their constructive, though not thoroughly supported, suggestions pertaining to changes in education.

  10. Type Ia Supernova Rate Measurements to Redshift 2.5 from Candles: Searching for Prompt Explosions in the Early Universe

    Science.gov (United States)

    Rodney, Steven A.; Riess, Adam G.; Strogler, Louis-Gregory; Dahlen, Tomas; Graur, Or; Casertano, Stefano; Dickinson, Mark E.; Ferguson, Henry C.; Garnavich, Peter; Cenko, Stephen Bradley

    2014-01-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope(HST) that surveyed a total area of approx. 0.25 deg(sup 2) with approx.900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z approx. 2.5. We classify approx. 24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z = 2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only approx. 3 Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (500 Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction isfP0.530.09stat0.100.10sys0.26, consistent with a delay time distribution that follows a simplet1power law for all timest40 Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z > 1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20 of all SN Ia explosions though further analysis and larger samples will be needed to examine that suggestion.

  11. A small amount of mini-charged dark matter could cool the baryons in the early Universe.

    Science.gov (United States)

    Muñoz, Julian B; Loeb, Abraham

    2018-05-01

    The dynamics of our Universe is strongly influenced by pervasive-albeit elusive-dark matter, with a total mass about five times the mass of all the baryons 1,2 . Despite this, its origin and composition remain a mystery. All evidence for dark matter relies on its gravitational pull on baryons, and thus such evidence does not require any non-gravitational coupling between baryons and dark matter. Nonetheless, some small coupling would explain the comparable cosmic abundances of dark matter and baryons 3 , as well as solving structure-formation puzzles in the pure cold-dark-matter models 4 . A vast array of observations has been unable to find conclusive evidence for any non-gravitational interactions of baryons with dark matter 5-9 . Recent observations by the EDGES collaboration, however, suggest that during the cosmic dawn, roughly 200 million years after the Big Bang, the baryonic temperature was half of its expected value 10 . This observation is difficult to reconcile with the standard cosmological model but could be explained if baryons are cooled down by interactions with dark matter, as expected if their interaction rate grows steeply at low velocities 11 . Here we report that if a small fraction-less than one per cent-of the dark matter has a mini-charge, a million times smaller than the charge on the electron, and a mass in the range of 1-100 times the electron mass, then the data 10 from the EDGES experiment can be explained while remaining consistent with all other observations. We also show that the entirety of the dark matter cannot have a mini-charge.

  12. Academic and non-academic career options for marine scientists. - Support measures for early career scientists offered at MARUM - Center for Marine Environmental Sciences, University of Bremen, Germany

    Science.gov (United States)

    Hebbeln, Dierk; Klose, Christina

    2015-04-01

    Early career scientists at MARUM cover a wide range of research topics and disciplines including geosciences, biology, chemistry, social sciences and law. Just as colourful as the disciplinary background of the people, are their ideas for their personal careers. With our services and programmes, we aim to address some important career planning needs of PhD students and early career Postdocs, both, for careers in science and for careers outside academia. For PhD students aiming to stay in science, MARUM provides funding opportunities for a research stay abroad for a duration of up to 6 months. A range of courses is offered to prepare for the first Postdoc position. These include trainings in applying for research funding, proposal writing and interview skills. Following MARUM lectures which are held once a month, early career scientists are offered the opportunity to talk to senior scientists from all over the world in an informal Meet&Greet. Mentoring and coaching programmes for women in science are offered in cooperation with the office for equal opportunities at the University of Bremen. These programmes offer an additional opportunity to train interpersonal skills and to develop personal career strategies including a focus on special challenges that especially women might (have to) face in the scientific community. Early career scientists aiming for a non-academic career find support on different levels. MARUM provides funding opportunities for placements in industry, administration, consulting or similar. We offer trainings in e.g. job hunting strategies or interview skills. For a deeper insight into jobs outside the academic world, we regularly invite professionals for informal fireside chats and career days. These events are organised in cooperation with other graduate programmes in the region to broaden the focus of both, the lecturers and the participants. A fundamental component of our career programmes is the active involvement of alumni of MARUM and our

  13. Conservative surgery and radiotherapy for early-stage breast cancer using a lung density correction: the University of Michigan experience

    International Nuclear Information System (INIS)

    Pierce, Lori J.; Strawderman, Myla H.; Douglas, Kathye R.; Lichter, Allen S.

    1997-01-01

    Purpose: Although an abundance of reports detail the successful use of definitive radiotherapy of the breast in the treatment in Stage I or II breast cancer, little data have been published concerning the use of lung density correction and its effect upon long-term outcome. As it has been the practice at the University of Michigan to routinely use lung density correction in the dose calculations to the breast, we retrospectively analyzed our results for local control, relapse-free, and overall survival. Methods and Materials: Clinical records were reviewed of 429 women with Stage I or II breast cancer treated with lumpectomy, axillary dissection, and breast irradiation with or without systemic chemo/hormonal therapy. Tangential radiotherapy fields delivering 45 to 50 Gy were used to treat the entire breast. A boost was delivered in 95% of cases for a total tumor bed dose of 60 to 66 Gy. All treatment plans were calculated using a lung density correction. Results: With a median follow up of 4.4 years, the 5-year actuarial rate of local control with local failure as the only site of first failure was 96% (95% CI 94-98%). Univariate analysis for local failure as only first failure found the following factors to statistically predict for increased risk of breast recurrence: young age (≤35 years old), premenopausal status, tumor size >2 cm, positive family history, and positive microscopic margins. Multivariate analysis revealed young age and margin status to be the only factors remaining significant for local failure. The 5-year actuarial relapse-free survival was 85% (95% CI 81-89%); overall survival at 5 years was 90% (95% CI 87-94%). Conclusions: Lung density correction results in rates of local control, disease-free, and overall survival at 5 years that compare favorably with series using noncorrected unit density calculations. While we will continue to update our results with increasing follow-up, our 5-year data indicate that the use of lung-density correction

  14. Type Ia supernova rate measurements to redshift 2.5 from CANDELS: Searching for prompt explosions in the early universe

    Energy Technology Data Exchange (ETDEWEB)

    Rodney, Steven A.; Riess, Adam G.; Graur, Or; Jones, David O. [Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218 (United States); Strolger, Louis-Gregory; Dahlen, Tomas; Casertano, Stefano; Ferguson, Henry C.; Koekemoer, Anton M. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Dickinson, Mark E. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Garnavich, Peter [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Hayden, Brian [E.O. Lawrence Berkeley National Lab, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Jha, Saurabh W.; McCully, Curtis; Patel, Brandon [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Kirshner, Robert P. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Mobasher, Bahram [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Weiner, Benjamin J. [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Cenko, S. Bradley [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Clubb, Kelsey I. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); and others

    2014-07-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope (HST) that surveyed a total area of ∼0.25 deg{sup 2} with ∼900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z ∼ 2.5. We classify ∼24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z = 2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only ∼3 Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (<500 Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction is f{sub P} = 0.53{sub stat0.10}{sup ±0.09}{sub sys0.26}{sup ±0.10}, consistent with a delay time distribution that follows a simple t {sup –1} power law for all times t > 40 Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z > 1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20% of all SN Ia explosions—though further analysis and larger samples will be needed to examine that suggestion.

  15. Early Onset of Type 1 Diabetes and Educational Field at Upper Secondary and University Level: Is Own Experience an Asset for a Health Care Career?

    Science.gov (United States)

    Steen Carlsson, Katarina

    2017-01-01

    Ill health in early life has a significant negative impact on school grades, grade repetition, educational level, and labor market outcomes. However, less is known about qualitative socio-economic consequences of a health shock in childhood or adolescence. We investigate the relationship between onset of type 1 diabetes up to age 15 and the probability of choosing and completing a health-oriented path at upper secondary and university level of education. We analyze the Swedish Childhood Diabetes Register, the National Educational Register, and other population registers in Sweden for 2756 people with type 1 diabetes and 10,020 matched population controls. Educational decisions are modeled as unsorted series of binary choices to assess the choice of educational field as a potential mechanism linking early life health to adult outcomes. The analyses reject the hypothesis of no systematic differences in choice of educational field between people with and without type 1 diabetes at both levels. The results are robust to selection on ability proxies and across sensitivity analysis. We conclude that the observed pro health-oriented educational choices among people with type 1 diabetes in our data are consistent with disease onset in childhood and adolescence having qualitative impact on life-course choices. PMID:28665347

  16. Early Onset of Type 1 Diabetes and Educational Field at Upper Secondary and University Level: Is Own Experience an Asset for a Health Care Career?

    Science.gov (United States)

    Lovén, Ida; Steen Carlsson, Katarina

    2017-06-30

    Ill health in early life has a significant negative impact on school grades, grade repetition, educational level, and labor market outcomes. However, less is known about qualitative socio-economic consequences of a health shock in childhood or adolescence. We investigate the relationship between onset of type 1 diabetes up to age 15 and the probability of choosing and completing a health-oriented path at upper secondary and university level of education. We analyze the Swedish Childhood Diabetes Register, the National Educational Register, and other population registers in Sweden for 2756 people with type 1 diabetes and 10,020 matched population controls. Educational decisions are modeled as unsorted series of binary choices to assess the choice of educational field as a potential mechanism linking early life health to adult outcomes. The analyses reject the hypothesis of no systematic differences in choice of educational field between people with and without type 1 diabetes at both levels. The results are robust to selection on ability proxies and across sensitivity analysis. We conclude that the observed pro health-oriented educational choices among people with type 1 diabetes in our data are consistent with disease onset in childhood and adolescence having qualitative impact on life-course choices.

  17. Plasma universe

    International Nuclear Information System (INIS)

    Alfven, H.

    1986-04-01

    Traditionally the views in our cosmic environment have been based on observations in the visual octave of the electromagnetic spectrum, during the last half-century supplemented by infrared and radio observations. Space research has opened the full spectrum. Of special importance are the X-ray-gamma-ray regions, in which a number of unexpected phenomena have been discovered. Radiations in these regions are likely to originate mainly from magnetised cosmic plasma. Such a medium may also emit synchrotron radiation which is observable in the radio region. If we try to base a model of the universe on the plasma phenomena mentioned we find that the plasma universe is drastically different from the traditional visual universe. Information about the plasma universe can also be obtained by extrapolation of laboratory experiments and magnetospheric in situ measurements of plasma. This approach is possible because it is likely that the basic properties of plasma are the same everywhere. In order to test the usefulness of the plasma universe model we apply it to cosmogony. Such an approach seems to be rather successful. For example, the complicated structure of the Saturnian C ring can be accounted for. It is possible to reconstruct certain phenomena 4-5 bilions years ago with an accuracy of better than 1 percent

  18. Gamma camera

    International Nuclear Information System (INIS)

    Conrad, B.; Heinzelmann, K.G.

    1975-01-01

    A gamma camera is described which obviates the distortion of locating signals generally caused by the varied light conductive capacities of the light conductors in that the flow of light through each light conductor may be varied by means of a shutter. A balancing of the flow of light through each of the individual light conductors, in effect, collective light conductors may be balanced on the basis of their light conductive capacities or properties, so as to preclude a distortion of the locating signals caused by the varied light conductive properties of the light conductors. Each light conductor has associated therewith two, relative to each other, independently adjustable shutters, of which one forms a closure member and the other an adjusting shutter. In this embodiment of the invention it is thus possible to block all of the light conductors leading to a photoelectric transducer, with the exception of those light conductors which are to be balanced. The balancing of the individual light conductors may then be obtained on the basis of the output signals of the photoelectric transducer. (auth)

  19. Gamma ray generator

    Science.gov (United States)

    Firestone, Richard B; Reijonen, Jani

    2014-05-27

    An embodiment of a gamma ray generator includes a neutron generator and a moderator. The moderator is coupled to the neutron generator. The moderator includes a neutron capture material. In operation, the neutron generator produces neutrons and the neutron capture material captures at least some of the neutrons to produces gamma rays. An application of the gamma ray generator is as a source of gamma rays for calibration of gamma ray detectors.

  20. High activity gamma irradiators developed in Hungary

    International Nuclear Information System (INIS)

    Stenger, V.

    1997-01-01

    The development of high activity Gamma irradiators began in Hungary already in the early years of 60s. The very first designs were serving research in irradiation chemistry, radiation physics, food and agricultural research, radiation sterilization, plastic radiation chemistry, radiobiology, cancer therapy, personal and high dose dosimetry, following the international trends. Domestic and new international demands forced us to design and construct High Activity Gamma Irradiators: Multipurpose Pilot, Portable and Large scale bulk, Multipurpose Industrial scale types

  1. Final results on the Jurassic-Cretaceous boundary in the Gresten Klippenbelt (Austria): Macro-, micro-, nannofossils, isotopes, geochemistry, susceptibility, gamma-log and palaeomagnetic data as environmental proxies of the early Penninic Ocean history

    Science.gov (United States)

    Lukeneder, A.; Halásová, E.; Kroh, A.; Mayrhofer, S.; Pruner, P.; Reháková, D.; Schnabl, P.; Sprovieri, M.

    2009-04-01

    radioactivity of the rock and represents a direct function of its clay-mineral content. Higher radioactivity reflects a higher clay content. The gamma-log curve supports the biostratigraphic data very well. The gamma response becomes gradually weaker in the upper, undisturbed part of the section (Nu10-Nu0, Berriasian). The lower part (Nu18-Nu10, Tithonian) of the section shows the highest gamma responses. The gamma curve pattern at Nutzhof therefore shows decreasing values what corresponds well with decreasing values of susceptibility as well with the contrastingly, increasing values in carbonate content (from 50 per cent up to 95 per cent CaCo3) and increasing grey scale values (up to 250). The above reported results strongly suggest that the section mirrors a change of the depositional position of the Nutzhof section from a shallower into a deeper region, and a more stable environment on the European Helvetic shelf to slope during the Late Jurassic to Early Cretaceous time. References Hardenbol, J., Thierry, J., Farley, M. B., Jacquin, T., de Graciansky, P. C. & Vail, P. R. (1998): Mesozoic and Cenozoic sequence stratigraphy of European basins. - SEMP, Special Publications, 60, 1998. Tulsa. Henning, S., Weissert, H., Bulot, L. 1999. C-isotope stratigraphy, a calibration tool between ammonite- and magnethostratigraphy: the Valanginian-Hauterivian transition. Geologica Carpathica, 50 (1), 91-96. Kroh, A., Lukeneder, A. 2009. Crinoids from the Late Jurassic of the Nutzhof section (Lower Austria, Gresten Klippenbelt). - Annalen des Naturhistorischen Museums in Wien, Serie A, 110: 383-399. Lukeneder A. 2009. New biostratigraphic ammonite data from the Jurassic/Cretaceous boundary at Nutzhof (Gresten Klippenbelt, Lower Austria) Annalen des Naturhistorischen Museums in Wien, Serie A, 110: 313-329. Pruner, P. Schnabl, P., Lukeneder A. 2009. Preliminary results of magnetostratigraphic investigations across the Jurassic/Cretaceous boundary strata at Nutzhof, Austria. Annalen des

  2. Future prospects for. gamma. -ray astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Fichtel, C [National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center

    1981-06-30

    As ..gamma..-ray astronomy moves from the discovery to the exploratory phase, the promise of ..gamma..-ray astrophysics noted by theorists in the late 1940s and 1950s is beginning to be realized. In the future, satellites should carry instruments that will have over an order of magnitude greater sensitivity than those flown thus far, and, for at least some portions of the ..gamma..-ray energy range, these detectors will also have substantially improved energy and angular resolution. The information to be obtained from these experiments should greatly enhance our knowledge of several astrophysical phenomena including the very energetic and nuclear processes associated with compact objects, astrophysical nucleosynthesis, solar particle acceleration, the chemical composition of the planets and other bodies of the Solar System, the structure of our Galaxy, the origin and dynamic pressure effects of the cosmic rays, high energy particles and energetic processes in other galaxies especially active ones, and the degree of matter-antimatter symmetry of the Universe. The ..gamma..-ray results of the forthcoming programs such as Gamma-I, the Gamma Ray Observatory, the ..gamma..-ray burst network, Solar Polar, and very high energy ..gamma..-ray telescopes on the ground will almost certainly provide justification for more sophisticated telescopes. These advanced instruments might be placed on the Space Platform currently under study by N.A.S.A.

  3. Investigation of early DNA damage after radioiodine therapy in patients with thyroid cancer using the gamma-H2AX focus assay

    International Nuclear Information System (INIS)

    Eberlein, U.; Lassmann, M.; Bluemel, C.; Buck, A.K.; Nowak, C.; Meineke, V.; Scherthan, H.

    2015-01-01

    of RIF reached a maximum in most patients (median: 0.51 RIF at t=4 h, range 0.36-0.74 RIF). This corresponded to a mean absorbed dose of (0.07±0.02) Gy. Later time points were characterized by a considerable decrease of RIF, agreeing with a diminished dose rate. An elevated number of excess RIF were still detectable 144 h after therapy. Conclusions: A combinatorial measurement of RIF and the absorbed dose to the blood at early time points after systemic administration of I-131 may be used to obtain data on the individual dose-response relationships after nuclide incorporation in-vivo. (authors)

  4. Galaxies in the Universe - 2nd Edition

    Science.gov (United States)

    Sparke, Linda S.; Gallagher, John S., III

    2006-04-01

    This extensively illustrated book presents the astrophysics of galaxies since their beginnings in the early Universe. It has been thoroughly revised to take into account the most recent observational data, and recent discoveries such as dark energy. There are new sections on galaxy clusters, gamma ray bursts and supermassive black holes. The authors explore the basic properties of stars and the Milky Way before working out towards nearby galaxies and the distant Universe. They discuss the structures of galaxies and how galaxies have developed, and relate this to the evolution of the Universe. The book also examines ways of observing galaxies across the whole electromagnetic spectrum, and explores dark matter and its gravitational pull on matter and light. This book is self-contained and includes several homework problems with hints. It is ideal for advanced undergraduate students in astronomy and astrophysics. • Completely updated to take into account the latest observational data and theoretical concepts • Throughly revised with new sections on dark energy, gamma ray bursts, and central black holes in galaxies • Contains problems with hints to the solutions

  5. Light Dawns on Dark Gamma-ray Bursts

    Science.gov (United States)

    2010-12-01

    Gamma-ray bursts are among the most energetic events in the Universe, but some appear curiously faint in visible light. The biggest study to date of these so-called dark gamma-ray bursts, using the GROND instrument on the 2.2-metre MPG/ESO telescope at La Silla in Chile, has found that these gigantic explosions don't require exotic explanations. Their faintness is now fully explained by a combination of causes, the most important of which is the presence of dust between the Earth and the explosion. Gamma-ray bursts (GRBs), fleeting events that last from less than a second to several minutes, are detected by orbiting observatories that can pick up their high energy radiation. Thirteen years ago, however, astronomers discovered a longer-lasting stream of less energetic radiation coming from these violent outbursts, which can last for weeks or even years after the initial explosion. Astronomers call this the burst's afterglow. While all gamma-ray bursts [1] have afterglows that give off X-rays, only about half of them were found to give off visible light, with the rest remaining mysteriously dark. Some astronomers suspected that these dark afterglows could be examples of a whole new class of gamma-ray bursts, while others thought that they might all be at very great distances. Previous studies had suggested that obscuring dust between the burst and us might also explain why they were so dim. "Studying afterglows is vital to further our understanding of the objects that become gamma-ray bursts and what they tell us about star formation in the early Universe," says the study's lead author Jochen Greiner from the Max-Planck Institute for Extraterrestrial Physics in Garching bei München, Germany. NASA launched the Swift satellite at the end of 2004. From its orbit above the Earth's atmosphere it can detect gamma-ray bursts and immediately relay their positions to other observatories so that the afterglows could be studied. In the new study, astronomers combined Swift

  6. Messengers of the universe: Session IV Summary

    International Nuclear Information System (INIS)

    Bernardini, Elisa; Serpico, Pasquale Dario

    2013-01-01

    Being stable, light and neutral weakly interacting particles, neutrinos are ideal messengers of the deep universe and a channel of choice in particular to explore the very high energy Galactic and Extragalactic sky, playing a synergic role most notably with gamma-ray observations. Neutrino astronomy—long after the SN1987A detection in the MeV range—is mature enough for decisive tests of astrophysical paradigms. Its current status constitutes one of the two big pillars of the “Messengers of the universe” session of the Neutrino Oscillation Workshop 2012. Neutrinos may also play a role in some cosmological contexts, such as the early universe and the dark matter problem. We review both aspects in this session summary report

  7. HERA: Illuminating Our Early Universe

    Science.gov (United States)

    DeBoer, David

    2014-06-01

    The Hydrogen Epoch of Reionization Arrays (HERA) roadmap is a staged plan for using the unique properties of the 21cm line from neutral hydrogen to probe our cosmic dawn, from the birth of the first stars and black holes, through the full reionization of the primordial intergalactic medium (IGM). HERA is a collaboration between the Precision Array Probing the Epoch of Reionization (PAPER), US-Murchison Widefield Array (MWA), and MIT Epoch of Reionization (MITEOR) teams.The first phase of the HERA roadmap entailed the operation of the PAPER and MWA telescopes to explore techniques and designs required to detect the primordial HI signal in the presence of radio continuum foreground emission some four orders of magnitude brighter. Studies with PAPER and the MWA have led to a new understanding of the interplay of foreground and instrumental systematics in the context of a three-dimensional cosmological intensity-mapping experiment. We are now able to remove foregrounds to the limits of our sensitivity with these instruments, culminating in the first physically meaningful upper limits on the power spectrum of 2 cm emission from reionization.Building on this understanding, the next stage of HERA entails a new 14m diameter antenna element that is optimized both for sensitivity and for minimizing foreground systematics. Arranging these elements in a compact hexagonal grid yields an array that facilitates calibration, leverages proven foreground removal techniques, and is scalable to large collecting areas. The HERA phase II will be located in the radio quiet environment of the SKA site in Karoo, South Africa, and have a sensitivity close to two orders of magnitude better than PAPER and the MWA, with broader frequency coverage, HERA can paint an uninterrupted picture through reionization, back to the end of the Dark Ages.This paper will present a summary of the current understanding of the signal characteristics and measurements and describe this planned HERA telescope to be built to detect and characterize the EoR power spectrum.

  8. First Time Rapid and Accurate Detection of Massive Number of Metal Absorption Lines in the Early Universe Using Deep Neural Network

    Science.gov (United States)

    Zhao, Yinan; Ge, Jian; Yuan, Xiaoyong; Li, Xiaolin; Zhao, Tiffany; Wang, Cindy

    2018-01-01

    Metal absorption line systems in the distant quasar spectra have been used as one of the most powerful tools to probe gas content in the early Universe. The MgII λλ 2796, 2803 doublet is one of the most popular metal absorption lines and has been used to trace gas and global star formation at redshifts between ~0.5 to 2.5. In the past, machine learning algorithms have been used to detect absorption lines systems in the large sky survey, such as Principle Component Analysis, Gaussian Process and decision tree, but the overall detection process is not only complicated, but also time consuming. It usually takes a few months to go through the entire quasar spectral dataset from each of the Sloan Digital Sky Survey (SDSS) data release. In this work, we applied the deep neural network, or “ deep learning” algorithms, in the most recently SDSS DR14 quasar spectra and were able to randomly search 20000 quasar spectra and detect 2887 strong Mg II absorption features in just 9 seconds. Our detection algorithms were verified with previously released DR12 and DR7 data and published Mg II catalog and the detection accuracy is 90%. This is the first time that deep neural network has demonstrated its promising power in both speed and accuracy in replacing tedious, repetitive human work in searching for narrow absorption patterns in a big dataset. We will present our detection algorithms and also statistical results of the newly detected Mg II absorption lines.

  9. Social anxiety and negative early life events in university students Eventos negativos na infância e ansiedade social em estudantes universitários

    Directory of Open Access Journals (Sweden)

    Cynthia Binelli

    2012-06-01

    Full Text Available INTRODUCTION: There is substantial evidence regarding the impact of negative life events during childhood on the aetiology of psychiatric disorders. We examined the association between negative early life events and social anxiety in a sample of 571 Spanish University students. METHODS: In a cross-sectional survey conducted in 2007, we collected data through a semistructured questionnaire of sociodemographic variables, personal and family psychiatric history, and substance abuse. We assessed the five early negative life events: (i the loss of someone close, (ii emotional abuse, (iii physical abuse, (iv family violence, and (v sexual abuse. All participants completed the Liebowitz Social Anxiety Scale. RESULTS: Mean (SD age was 21 (4.5, 75% female, LSAS score was 40 (DP = 22, 14.2% had a psychiatric family history and 50.6% had negative life events during childhood. Linear regression analyses, after controlling for age, gender, and family psychiatric history, showed a positive association between family violence and social score (p = 0.03. None of the remaining stressors produced a significant increase in LSAS score (p > 0.05. CONCLUSION: University students with high levels of social anxiety presented higher prevalence of negative early life events. Thus, childhood family violence could be a risk factor for social anxiety in such a population.INTRODUÇÃO: Existem evidências substanciais sobre o impacto de eventos negativos da vida durante a infância na etiologia dos transtornos psiquiátricos. Examinamos a associação entre os eventos negativos ocorridos na infância e a ansiedade social em uma amostra de 571 estudantes universitários espanhóis. MÉTODOS: Em um estudo transversal realizado em 2007, foram coletados os dados de variáveis sociodemográficas, história psiquiátrica pessoal e familiar e abuso de substâncias por meio de um questionário semiestruturado e avaliamos cinco eventos negativos ocorridos na infância: (i a perda de

  10. Cosmic gamma bursts

    International Nuclear Information System (INIS)

    Ehstulin, I.V.

    1980-01-01

    A brief consideration is being given to the history of cosmic gamma burst discovery and modern knowledge of their properties. The time dependence of gamma bursts is described and their possible sources are discussed

  11. Annihilation vs. Decay: Constraining dark matter properties from a gamma-ray detection

    CERN Document Server

    Palomares-Ruiz, Sergio

    2010-01-01

    Most proposed dark matter candidates are stable and are produced thermally in the early Universe. However, there is also the possibility of unstable (but long-lived) dark matter, produced thermally or otherwise. We propose a strategy to distinguish between dark matter annihilation and/or decay in the case that a clear signal is detected in gamma-ray observations of Milky Way dwarf spheroidal galaxies with current or future gamma-ray experiments. The sole measurement of the energy spectrum of an indirect signal would render the discrimination between these cases impossible. We show that by examining the dependence of the intensity and energy spectrum on the angular distribution of the emission, the origin could be identified as decay, annihilation, or both. In addition, once the type of signal is established, we show how these measurements could help to extract information about the dark matter properties, including mass, annihilation cross section, lifetime, dominant annihilation and decay channels, and the p...

  12. Fermi-LAT View of Bright Flaring Gamma-Ray Blazars

    Science.gov (United States)

    Bastieri, D.; Ciprini, S.; Gasparrini, D.

    2011-06-01

    The Fermi LAT provides a continuous and uniform monitoring of the Universe in the gamma-ray band. During the first year many gamma-ray blazar flares, some unidentified transients and emission by the Sun while in a quiet state were promptly detected. This is mainly due to the design of the mission, featuring a detector, the LAT with a wide field of view, and to the operation of the spacecraft itself, that can cover every region of the sky every 3 hours. Nevertheless, the scientific exploitation of this monitoring is more fruitful when early information about transients reaches a broader community. In this respect, the indefatigable activity of flare advocates, who worked on weekly shifts to validate the results and quickly broadcast information about flares and new detections, was the key to most scientific results.

  13. Language Outcomes in Deaf or Hard of Hearing Teenagers Who Are Spoken Language Users: Effects of Universal Newborn Hearing Screening and Early Confirmation.

    Science.gov (United States)

    Pimperton, Hannah; Kreppner, Jana; Mahon, Merle; Stevenson, Jim; Terlektsi, Emmanouela; Worsfold, Sarah; Yuen, Ho Ming; Kennedy, Colin R

    This study aimed to examine whether (a) exposure to universal newborn hearing screening (UNHS) and b) early confirmation of hearing loss were associated with benefits to expressive and receptive language outcomes in the teenage years for a cohort of spoken language users. It also aimed to determine whether either of these two variables was associated with benefits to relative language gain from middle childhood to adolescence within this cohort. The participants were drawn from a prospective cohort study of a population sample of children with bilateral permanent childhood hearing loss, who varied in their exposure to UNHS and who had previously had their language skills assessed at 6-10 years. Sixty deaf or hard of hearing teenagers who were spoken language users and a comparison group of 38 teenagers with normal hearing completed standardized measures of their receptive and expressive language ability at 13-19 years. Teenagers exposed to UNHS did not show significantly better expressive (adjusted mean difference, 0.40; 95% confidence interval [CI], -0.26 to 1.05; d = 0.32) or receptive (adjusted mean difference, 0.68; 95% CI, -0.56 to 1.93; d = 0.28) language skills than those who were not. Those who had their hearing loss confirmed by 9 months of age did not show significantly better expressive (adjusted mean difference, 0.43; 95% CI, -0.20 to 1.05; d = 0.35) or receptive (adjusted mean difference, 0.95; 95% CI, -0.22 to 2.11; d = 0.42) language skills than those who had it confirmed later. In all cases, effect sizes were of small size and in favor of those exposed to UNHS or confirmed by 9 months. Subgroup analysis indicated larger beneficial effects of early confirmation for those deaf or hard of hearing teenagers without cochlear implants (N = 48; 80% of the sample), and these benefits were significant in the case of receptive language outcomes (adjusted mean difference, 1.55; 95% CI, 0.38 to 2.71; d = 0.78). Exposure to UNHS did not account for significant

  14. Gamma ray astronomy

    International Nuclear Information System (INIS)

    Broomhead, Laurent.

    1980-01-01

    The nuclear gamma astronomy is presented, in particular the Gamma Ray Observatory, an enormous eight tonnes machine fitted with gamma telescopes, scheduled for launching around 1985. It is thereby hoped to study the natural nuclear reactions which occur when stars explode [fr

  15. The many phases of gamma-ray burst afterglows

    NARCIS (Netherlands)

    Leventis, K.

    2013-01-01

    Gamma-ray bursts are the brightest sources in the universe. Their afterglows have been observed for about 15 years now, and their study has greatly advanced our understanding of these, mysterious until recently, events. In a way, gamma-ray bursts can be seen as huge cosmic bombs which convert

  16. Supernova sheds light on gamma-ray bursts

    CERN Multimedia

    2003-01-01

    On 29 March the HETE-II satellite detected the most violent explosion in the universe to date - an enormous burst of gamma rays. Observers across the world recorded and studied the event. It appears to prove that gamma ray bursts originate in supernovae (1 page)

  17. Analyzer for gamma cameras diagnostic

    International Nuclear Information System (INIS)

    Oramas Polo, I.; Osorio Deliz, J. F.; Diaz Garcia, A.

    2013-01-01

    This research work was carried out to develop an analyzer for gamma cameras diagnostic. It is composed of an electronic system that includes hardware and software capabilities, and operates from the acquisition of the 4 head position signals of a gamma camera detector. The result is the spectrum of the energy delivered by nuclear radiation coming from the camera detector head. This system includes analog processing of position signals from the camera, digitization and the subsequent processing of the energy signal in a multichannel analyzer, sending data to a computer via a standard USB port and processing of data in a personal computer to obtain the final histogram. The circuits are composed of an analog processing board and a universal kit with micro controller and programmable gate array. (Author)

  18. Gamma Ray Bursts as Cosmological Probes with EXIST

    Science.gov (United States)

    Hartmann, Dieter; EXIST Team

    2006-12-01

    The EXIST mission, studied as a Black Hole Finder Probe within NASA's Beyond Einstein Program, would, in its current design, trigger on 1000 Gamma Ray Bursts (GRBs) per year (Grindlay et al, this meeting). The redshift distribution of these GRBs, using results from Swift as a guide, would probe the z > 7 epoch at an event rate of > 50 per year. These bursts trace early cosmic star formation history, point to a first generation of stellar objects that reionize the universe, and provide bright beacons for absorption line studies with groundand space-based observatories. We discuss how EXIST, in conjunction with other space missions and future large survey programs such as LSST, can be utilized to advance our understanding of cosmic chemical evolution, the structure and evolution of the baryonic cosmic web, and the formation of stars in low metallicity environments.

  19. New program and boundary plasma research in GAMMA 10 modification (GAMMA-PDX)

    International Nuclear Information System (INIS)

    Imai, Tsuyoshi

    2011-01-01

    GAMMA 10 is the world's largest tandem mirror machine. Since the incorporation of national universities in 2004, many R and D activities taking advantage of its features have been performed in GAMMA 10 to contribute to the development of thermonuclear fusion researches. In the second mid-term plan since 2010, modification of the machine has been proposed to start boundary plasma research projects. Cooperative studies with other groups in Japan on divertor plasmas and particle transports are conducted by taking advantage of the potential control ability and the availability of the hot ion flux of GAMMA 10. (J.P.N.)

  20. Reactor gamma spectrometry: status

    International Nuclear Information System (INIS)

    Gold, R.; Kaiser, B.J.

    1979-01-01

    Current work is described for Compton Recoil Gamma-Ray Spectrometry including developments in experimental technique as well as recent reactor spectrometry measurements. The current status of the method is described concerning gamma spectromoetry probe design and response characteristics. Emphasis is given to gamma spectrometry work in US LWR and BR programs. Gamma spectrometry in BR environments are outlined by focussing on start-up plans for the Fast Test Reactor (FTR). Gamma spectrometry results are presented for a LWR pressure vessel mockup in the Poolside Critical Assembly (PCA) at Oak Ridge National Laboratory

  1. The second-generation z (redshift) and early universe spectrometer. I. First-light observation of a highly lensed local-ulirg analog at high-z

    Energy Technology Data Exchange (ETDEWEB)

    Ferkinhoff, Carl; Brisbin, Drew; Parshley, Stephen; Nikola, Thomas; Stacey, Gordon J.; Schoenwald, Justin; Riechers, Dominik [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Higdon, James L.; Higdon, Sarah J. U. [Department of Physics, Georgia Southern University, Statesboro, GA 30460 (United States); Verma, Aprajita [Department of Physics, University of Oxford, Oxford, OX1 3RH (United Kingdom); Hailey-Dunsheath, Steven [California Institute of Technology, Pasadena, CA 91125 (United States); Menten, Karl M.; Güsten, Rolf; Weiß, Axel [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Irwin, Kent; Cho, Hsiao M. [NIST Boulder, Boulder, CO 80305 (United States); Niemack, Michael [Department of Physics, Cornell University, Ithaca, NY 14853 (United States); Halpern, Mark; Amiri, Mandana [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Hasselfield, Matthew, E-mail: carl.ferkinhoff@cornell.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); and others

    2014-01-10

    We recently commissioned our new spectrometer, the second-generation z(Redshift) and Early Universe Spectrometer (ZEUS-2) on the Atacama Pathfinder Experiment telescope. ZEUS-2 is a submillimeter grating spectrometer optimized for detecting the faint and broad lines from distant galaxies that are redshifted into the telluric windows from 200 to 850 μm. It uses a focal plane array of transition-edge sensed bolometers, the first use of these arrays for astrophysical spectroscopy. ZEUS-2 promises to be an important tool for studying galaxies in the years to come because of its synergy with Atacama Large Millimeter Array and its capabilities in the short submillimeter windows that are unique in the post-Herschel era. Here, we report on our first detection of the [C II] 158 μm line with ZEUS-2. We detect the line at z ∼ 1.8 from H-ATLAS J091043.1–000322 with a line flux of (6.44 ± 0.42) × 10{sup –18} W m{sup –2}. Combined with its far-IR luminosity and a new Herschel-PACS detection of the [O I] 63 μm line, we model the line emission as coming from a photo-dissociation region with far-ultraviolet radiation field, G ∼ 2 × 10{sup 4} G {sub 0}, gas density, n ∼ 1 × 10{sup 3} cm{sup –3} and size between ∼0.4 and 1 kpc. On the basis of this model, we conclude that H-ATLAS J091043.1–000322 is a high-redshift analog of a local ultra-luminous IR galaxy; i.e., it is likely the site of a compact starburst caused by a major merger. Further identification of these merging systems is important for constraining galaxy formation and evolution models.

  2. The Second-generation z (Redshift) and Early Universe Spectrometer. I. First-light Observation of a Highly Lensed Local-ulirg Analog at High-z

    Science.gov (United States)

    Ferkinhoff, Carl; Brisbin, Drew; Parshley, Stephen; Nikola, Thomas; Stacey, Gordon J.; Schoenwald, Justin; Higdon, James L.; Higdon, Sarah J. U.; Verma, Aprajita; Riechers, Dominik; Hailey-Dunsheath, Steven; Menten, Karl M.; Güsten, Rolf; Weiß, Axel; Irwin, Kent; Cho, Hsiao M.; Niemack, Michael; Halpern, Mark; Amiri, Mandana; Hasselfield, Matthew; Wiebe, D. V.; Ade, Peter A. R.; Tucker, Carol E.

    2014-01-01

    We recently commissioned our new spectrometer, the second-generation z(Redshift) and Early Universe Spectrometer (ZEUS-2) on the Atacama Pathfinder Experiment telescope. ZEUS-2 is a submillimeter grating spectrometer optimized for detecting the faint and broad lines from distant galaxies that are redshifted into the telluric windows from 200 to 850 μm. It uses a focal plane array of transition-edge sensed bolometers, the first use of these arrays for astrophysical spectroscopy. ZEUS-2 promises to be an important tool for studying galaxies in the years to come because of its synergy with Atacama Large Millimeter Array and its capabilities in the short submillimeter windows that are unique in the post-Herschel era. Here, we report on our first detection of the [C II] 158 μm line with ZEUS-2. We detect the line at z ~ 1.8 from H-ATLAS J091043.1-000322 with a line flux of (6.44 ± 0.42) × 10-18 W m-2. Combined with its far-IR luminosity and a new Herschel-PACS detection of the [O I] 63 μm line, we model the line emission as coming from a photo-dissociation region with far-ultraviolet radiation field, G ~ 2 × 104 G 0, gas density, n ~ 1 × 103 cm-3 and size between ~0.4 and 1 kpc. On the basis of this model, we conclude that H-ATLAS J091043.1-000322 is a high-redshift analog of a local ultra-luminous IR galaxy; i.e., it is likely the site of a compact starburst caused by a major merger. Further identification of these merging systems is important for constraining galaxy formation and evolution models.

  3. The second-generation z (redshift) and early universe spectrometer. I. First-light observation of a highly lensed local-ulirg analog at high-z

    International Nuclear Information System (INIS)

    Ferkinhoff, Carl; Brisbin, Drew; Parshley, Stephen; Nikola, Thomas; Stacey, Gordon J.; Schoenwald, Justin; Riechers, Dominik; Higdon, James L.; Higdon, Sarah J. U.; Verma, Aprajita; Hailey-Dunsheath, Steven; Menten, Karl M.; Güsten, Rolf; Weiß, Axel; Irwin, Kent; Cho, Hsiao M.; Niemack, Michael; Halpern, Mark; Amiri, Mandana; Hasselfield, Matthew

    2014-01-01

    We recently commissioned our new spectrometer, the second-generation z(Redshift) and Early Universe Spectrometer (ZEUS-2) on the Atacama Pathfinder Experiment telescope. ZEUS-2 is a submillimeter grating spectrometer optimized for detecting the faint and broad lines from distant galaxies that are redshifted into the telluric windows from 200 to 850 μm. It uses a focal plane array of transition-edge sensed bolometers, the first use of these arrays for astrophysical spectroscopy. ZEUS-2 promises to be an important tool for studying galaxies in the years to come because of its synergy with Atacama Large Millimeter Array and its capabilities in the short submillimeter windows that are unique in the post-Herschel era. Here, we report on our first detection of the [C II] 158 μm line with ZEUS-2. We detect the line at z ∼ 1.8 from H-ATLAS J091043.1–000322 with a line flux of (6.44 ± 0.42) × 10 –18 W m –2 . Combined with its far-IR luminosity and a new Herschel-PACS detection of the [O I] 63 μm line, we model the line emission as coming from a photo-dissociation region with far-ultraviolet radiation field, G ∼ 2 × 10 4 G 0 , gas density, n ∼ 1 × 10 3 cm –3 and size between ∼0.4 and 1 kpc. On the basis of this model, we conclude that H-ATLAS J091043.1–000322 is a high-redshift analog of a local ultra-luminous IR galaxy; i.e., it is likely the site of a compact starburst caused by a major merger. Further identification of these merging systems is important for constraining galaxy formation and evolution models.

  4. First Detections of the [N II] 122 micron Line at High Redshift: Demonstrating the Utility of the Line for Studying Galaxies in the Early Universe

    Science.gov (United States)

    Ferkinhoff, Carl; Brisbin, Drew; Nikola, Thomas; Parshley, Stephen C.; Stacey, Gordon J.; Phillips, Thomas G.; Falgarone, Edith; Benford, Dominic J.; Staguhn, Johannes G.; Tucker, Carol E.

    2011-01-01

    We report the first detections of the [N II] 122 micron line from a high-redshift galaxy. The line was strongly (>6(sigma)) detected from SMMJ02399-0136, and H1413 + 117 (the Cloverleaf QSO) using the Redshift (zeta) and Early Universe Spectrometer on the Caltech Submillimeter Observatory. The lines from both sources are quite bright with line to far-infrared (FIR) continuum luminosity ratios that are approx.7.0 x 10(exp -4) (Cloverleaf) and 2.1 x 10(exo -3) (SMMJ02399). With ratios 2-10 times larger than the average value for nearby galaxies, neither source exhibits the line to continuum deficits seen in nearby sources. The line strengths also indicate large ionized gas fractions, approx.8%-17% of the molecUlar gas mass. The [O III]/[N II] line ratio is very sensitive to the effective temperature of ionizing stars and the ionization parameter for emission arising in the narrow-line region (NLR) of an active galactic nucleus (AGN). Using Our previous detection of the [O III] 88 micron line, the [O III]/[N II]line ratio for SMMJ02399-0136 indicates that the dominant source of the line emission is either stellar H II regions ionized by O9.5 stars, or the NLR of the AGN with ionization parameter log(U) = -3.3 to -4.0. A composite system, where 30%-50% of the FIR lines arise in the NLR also matches the data. The Cloverleaf is best modeled by a superposition of approx.200 M82-like starbursts accounting for all of the FIR emission and 43% of the [N II]line. The remainder may come from the NLR. This war!< demonstrates the utility of the [N II] and [O III] lines in constraining properties of the ionized medium.

  5. First Detections of the [NII] 122 Micrometer Line at High Redshift: Demonstrating the Utility of the Line for Studying Galaxies in the Early Universe

    Science.gov (United States)

    Ferkinhoff, Carl; Brisbin, Drew; Nikola, Thomas; Parshley, Stephen C.; Stacey, Gordon J.; Phillips, Thomas G.; Falgarone, Edith; Benford, Dominic J.; Staguhn, Johannes G.; Tucker, Carol E.

    2011-01-01

    We report the first detections of the [NIl] 122 {\\mu} m line from a high redshift galaxy. The line was strongly (> 6{\\sigma}) detected from SMMJ02399-0136, and HI413+ 117 (the Cloverleaf QSO) using the Redshift(z) and Early Universe Spectrometer (ZEUS) on the CSO. The lines from both sources are quite bright with line-to-FIR continuum luminosity ratios that are approx.7.0x10(exp -4) (Cloverleaf) and 2.1x10(exp -3) (SMMJ02399). With ratios 2-10 times larger than the average value for nearby galaxies, neither source exhibits the line-to-continuum deficits seen in nearby sources. The line strengths also indicate large ionized gas fractions, approx.8 to 17% of the molecular gas mass. The [OIII]/[NII] line ratio is very sensitive to the effective temperature of ionizing stars and the ionization parameter for emission arising in the narrow-line region (NLR) of an AGN. Using our previous detection of the [01II] 88 {\\mu}m line, the [OIII]/ [NIl] line ratio for SMMJ02399-0136 indicates the dominant source of the line emission is either stellar HII regions ionized by 09.5 stars, or the NLR of the AGN with ionization parameter 10g(U) = -3.3 to -4.0. A composite system, where 30 to 50% of the FIR lines arise in the NLR also matches the data. The Cloverleaf is best modeled by a superposition of approx.200 M82like starbursts accounting for all of the FIR emission and 43% of the [NIl] line. The remainder may come from the NLR. This work demonstrates the utility of the [NIl] and [OIII] lines in constraining properties of the ionized medium.

  6. The Gamma-Ray Imager GRI

    Science.gov (United States)

    Wunderer, Cornelia B.; GRI Collaboration

    2008-03-01

    Observations of the gamma-ray sky reveal the most powerful sources and the most violent events in the Universe. While at lower wavebands the observed emission is generally dominated by thermal processes, the gamma-ray sky provides us with a view on the non-thermal Universe. Here particles are accelerated to extreme relativistic energies by mechanisms which are still poorly understood, and nuclear reactions are synthesizing the basic constituents of our world. Cosmic accelerators and cosmic explosions are major science themes that are addressed in the gamma-ray regime. ESA's INTEGRAL observatory currently provides the astronomical community with a unique tool to investigate the sky up to MeV energies and hundreds of sources, new classes of objects, extraordinary views of antimatter annihilation in our Galaxy, and fingerprints of recent nucleosynthesis processes have been discovered. NASA's GLAST mission will similarly take the next step in surveying the high-energy ( GeV) sky, and NuSTAR will pioneer focusing observations at hard X-ray energies (to 80 keV). There will be clearly a growing need to perform deeper, more focused investigations of gamma-ray sources in the 100-keV to MeV regime. Recent technological advances in the domain of gamma-ray focusing using Laue diffraction and multilayer-coated mirror techniques have paved the way towards a gamma-ray mission, providing major improvements compared to past missions regarding sensitivity and angular resolution. Such a future Gamma-Ray Imager will allow the study of particle acceleration processes and explosion physics in unprecedented detail, providing essential clues on the innermost nature of the most violent and most energetic processes in the Universe.

  7. Properties of the Intergalactic Magnetic Field Constrained by Gamma-Ray Observations of Gamma-Ray Bursts

    Energy Technology Data Exchange (ETDEWEB)

    Veres, P.; Dermer, C. D.; Dhuga, K. S. [Department of Physics, George Washington University, Washington, DC 20052 (United States)

    2017-09-20

    The magnetic field in intergalactic space gives important information about magnetogenesis in the early universe. The properties of this field can be probed by searching for radiation of secondary e {sup +} e {sup −} pairs created by TeV photons that produce GeV range radiation by Compton-scattering cosmic microwave background photons. The arrival times of the GeV “echo” photons depend strongly on the magnetic field strength and coherence length. A Monte Carlo code that accurately treats pair creation is developed to simulate the spectrum and time-dependence of the echo radiation. The extrapolation of the spectrum of powerful gamma-ray bursts (GRBs) like GRB 130427A to TeV energies is used to demonstrate how the intergalactic magnetic field can be constrained if it falls in the 10{sup −21}–10{sup −17} G range for a 1 Mpc coherence length.

  8. GammaWorkshops Proceedings

    International Nuclear Information System (INIS)

    Ramebaeck, H.; Straelberg, E.; Klemola, S.; Nielsen, Sven P.; Palsson, S.E.

    2012-01-01

    Due to a sparse interaction during the last years between practioners in gamma ray spectrometry in the Nordic countries, a NKS activity was started in 2009. This GammaSem was focused on seminars relevant to gamma spectrometry. A follow up seminar was held in 2010. As an outcome of these activities it was suggested that the 2011 meeting should be focused on practical issues, e.g. different corrections needed in gamma spectrometric measurements. This three day's meeting, GammaWorkshops, was held in September at Risoe-DTU. Experts on different topics relevant for gamma spectrometric measurements were invited to the GammaWorkshops. The topics included efficiency transfer, true coincidence summing corrections, self-attenuation corrections, measurement of natural radionuclides (natural decay series), combined measurement uncertainty calculations, and detection limits. These topics covered both lectures and practical sessions. The practical sessions included demonstrations of tools for e.g. corrections and calculations of the above meantioned topics. (Author)

  9. Dose fractionated gamma knife radiosurgery for large arteriovenous malformations on daily or alternate day schedule outside the linear quadratic model: Proof of concept and early results. A substitute to volume fractionation.

    Science.gov (United States)

    Mukherjee, Kanchan Kumar; Kumar, Narendra; Tripathi, Manjul; Oinam, Arun S; Ahuja, Chirag K; Dhandapani, Sivashanmugam; Kapoor, Rakesh; Ghoshal, Sushmita; Kaur, Rupinder; Bhatt, Sandeep

    2017-01-01

    To evaluate the feasibility, safety and efficacy of dose fractionated gamma knife radiosurgery (DFGKRS) on a daily schedule beyond the linear quadratic (LQ) model, for large volume arteriovenous malformations (AVMs). Between 2012-16, 14 patients of large AVMs (median volume 26.5 cc) unsuitable for surgery or embolization were treated in 2-3 of DFGKRS sessions. The Leksell G frame was kept in situ during the whole procedure. 86% (n = 12) patients had radiologic evidence of bleed, and 43% (n = 6) had presented with a history of seizures. 57% (n = 8) patients received a daily treatment for 3 days and 43% (n = 6) were on an alternate day (2 fractions) regimen. The marginal dose was split into 2 or 3 fractions of the ideal prescription dose of a single fraction of 23-25 Gy. The median follow up period was 35.6 months (8-57 months). In the three-fraction scheme, the marginal dose ranged from 8.9-11.5 Gy, while in the two-fraction scheme, the marginal dose ranged from 11.3-15 Gy at 50% per fraction. Headache (43%, n = 6) was the most common early postoperative complication, which was controlled with short course steroids. Follow up evaluation of at least three years was achieved in seven patients, who have shown complete nidus obliteration in 43% patients while the obliteration has been in the range of 50-99% in rest of the patients. Overall, there was a 67.8% reduction in the AVM volume at 3 years. Nidus obliteration at 3 years showed a significant rank order correlation with the cumulative prescription dose (p 0.95, P value 0.01), with attainment of near-total (more than 95%) obliteration rates beyond 29 Gy of the cumulative prescription dose. No patient receiving a cumulative prescription dose of less than 31 Gy had any severe adverse reaction. In co-variate adjusted ordinal regression, only the cumulative prescription dose had a significant correlation with common terminology criteria for adverse events (CTCAE) severity (P value 0.04), independent of age, AVM volume

  10. Gamma-ray bursts at high redshift

    NARCIS (Netherlands)

    Wijers, R.A.M.J.

    1999-01-01

    Gamma-ray bursts are much brighter than supernovae, and could therefore possibly probe the Universe to high redshift. The presently established GRB redshifts range from 0.83 to 5, and quite possibly even beyond that. Since most proposed mechanisms for GRB link them closely to deaths of massive

  11. Fermi Large Area Telescope Bright Gamma-ray Source List

    Energy Technology Data Exchange (ETDEWEB)

    Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /KIPAC, Menlo Park /SLAC; Ajello, M.; /KIPAC, Menlo Park /SLAC; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U., OKC /Stockholm U.; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Band, D.L.; /NASA, Goddard /NASA, Goddard; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bastieri, Denis; /INFN, Padua /Padua U.; Bechtol, K.; /KIPAC, Menlo Park /SLAC; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /KIPAC, Menlo Park /SLAC; Bignami, G.F.; /Pavia U.; Bloom, Elliott D.; /KIPAC, Menlo Park /SLAC; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /KIPAC, Menlo Park /SLAC; Bregeon, J.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Burnett, Thompson H.; /Washington U., Seattle /Bari U. /INFN, Bari /KIPAC, Menlo Park /SLAC /IASF, Milan /IASF, Milan /DAPNIA, Saclay /ASDC, Frascati /INFN, Perugia /Perugia U. /KIPAC, Menlo Park /SLAC /George Mason U. /Naval Research Lab, Wash., D.C. /NASA, Goddard /KIPAC, Menlo Park /SLAC /INFN, Perugia /Perugia U. /KIPAC, Menlo Park /SLAC /Montpellier U. /Sonoma State U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm /Stockholm U. /KIPAC, Menlo Park /SLAC /ASDC, Frascati /NASA, Goddard /Maryland U. /Naval Research Lab, Wash., D.C. /INFN, Trieste /Pavia U. /Bari U. /INFN, Bari /KIPAC, Menlo Park /SLAC /UC, Santa Cruz /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /SLAC /KIPAC, Menlo Park /SLAC /Montpellier U. /Bari U. /INFN, Bari /Ecole Polytechnique /NASA, Goddard; /more authors..

    2009-05-15

    Following its launch in 2008 June, the Fermi Gamma-ray Space Telescope (Fermi) began a sky survey in August. The Large Area Telescope (LAT) on Fermi in three months produced a deeper and better resolved map of the {gamma}-ray sky than any previous space mission. We present here initial results for energies above 100 MeV for the 205 most significant (statistical significance greater than {approx}10{sigma}) {gamma}-ray sources in these data. These are the best characterized and best localized point-like (i.e., spatially unresolved) {gamma}-ray sources in the early mission data.

  12. Comparison of full width at half maximum and penumbra of different Gamma Knife models.

    Science.gov (United States)

    Asgari, Sepideh; Banaee, Nooshin; Nedaie, Hassan Ali

    2018-01-01

    As a radiosurgical tool, Gamma Knife has the best and widespread name recognition. Gamma Knife is a noninvasive intracranial technique invented and developed by Swedish neurosurgeon Lars Leksell. The first commercial Leksell Gamma Knife entered the therapeutic armamentarium at the University of Pittsburgh in the United States on August 1987. Since that time, different generation of Gamma Knife developed. In this study, the technical points and dosimetric parameters including full width at half maximum and penumbra on different generation of Gamma Knife will be reviewed and compared. The results of this review study show that the rotating gamma system provides a better dose conformity.

  13. THE CHEMISTRY OF POPULATION III SUPERNOVA EJECTA. II. THE NUCLEATION OF MOLECULAR CLUSTERS AS A DIAGNOSTIC FOR DUST IN THE EARLY UNIVERSE

    International Nuclear Information System (INIS)

    Cherchneff, Isabelle; Dwek, Eli

    2010-01-01

    . III SNe chiefly form silica and/or silicates, and pure silicon grains whereas their lower mass counterparts form a dust mixture dominated by silica and/or silicates, pure silicon, and iron sulfides. Amorphous carbon can only condense via the nucleation of carbon chains and rings characteristic of the synthesis of fullerenes when the ejecta carbon-rich zone is deprived of He + . The first dust enrichment to the primordial gas in the early universe from Pop. III massive SN comprises primarily pure silicon, silica, and silicates. If carbon dust is present at redshift z > 6, alternative dust sources must be considered.

  14. The Chemistry of Population III Supernova Ejecta. II. The Nucleation of Molecular Clusters as a Diagnostic for Dust in the Early Universe

    Science.gov (United States)

    Cherchneff, Isabelle; Dwek, Eli

    2010-04-01

    chiefly form silica and/or silicates, and pure silicon grains whereas their lower mass counterparts form a dust mixture dominated by silica and/or silicates, pure silicon, and iron sulfides. Amorphous carbon can only condense via the nucleation of carbon chains and rings characteristic of the synthesis of fullerenes when the ejecta carbon-rich zone is deprived of He+. The first dust enrichment to the primordial gas in the early universe from Pop. III massive SN comprises primarily pure silicon, silica, and silicates. If carbon dust is present at redshift z > 6, alternative dust sources must be considered.

  15. OBSERVATION OF CORRELATED OPTICAL AND GAMMA EMISSIONS FROM GRB 081126

    International Nuclear Information System (INIS)

    Klotz, A.; Boer, M.; Gendre, B.; Atteia, J. L.; Coward, D. M.; Imerito, A. C.

    2009-01-01

    We present an analysis of time-resolved optical emissions observed from the gamma-ray burst GRB 081126 during the prompt phase. The analysis employed time-resolved photometry using optical data obtained by the TAROT telescope, using BAT data from the Swift spacecraft, and time-resolved spectroscopy at high energies from the GBM instrument onboard the Fermi spacecraft. The optical emission of GRB 081126 is found to be compatible with the second gamma emission pulse shifted by a positive time lag of 8.4 ± 3.9 s. This is the first well-resolved observation of a time lag between optical and gamma emissions during a gamma-ray burst. Our observations could potentially provide new constraints on the fireball model for gamma-ray burst early emissions. Furthermore, observations of time lags between optical and gamma ray photons provides an exciting opportunity to constrain quantum gravity theories.

  16. A Correlated Optical and Gamma Emission from GRB 081126A

    International Nuclear Information System (INIS)

    Gendre, B.; Klotz, A.; Atteia, J. L.; Boeer, M.; Coward, D. M.; Imerito, A. C.

    2010-01-01

    We present an analysis of time-resolved optical emissions observed from the gamma-ray burst GRB 081126 during the prompt phase. The analysis employed time-resolved photometry using optical data obtained by the TAROT telescope, BAT data from the Swift spacecraft and time-resolved spectroscopy at high energies from the GBM instrument onboard the Fermi spacecraft. The optical emission of GRB 081126 is found to be compatible with the second gamma emission pulse shifted by a positive time-lag of 8.4±3.9 sec. This is the first well resolved observation of a time lag between optical and gamma emissions during a gamma-ray burst. Our observations could potentially provide new constraints on the fireball model for gamma ray burst early emissions. Furthermore, observations of time-lags between optical and gamma ray photons provides an exciting opportunity to constrain quantum gravity theories.

  17. Gamma Splines and Wavelets

    Directory of Open Access Journals (Sweden)

    Hannu Olkkonen

    2013-01-01

    Full Text Available In this work we introduce a new family of splines termed as gamma splines for continuous signal approximation and multiresolution analysis. The gamma splines are born by -times convolution of the exponential by itself. We study the properties of the discrete gamma splines in signal interpolation and approximation. We prove that the gamma splines obey the two-scale equation based on the polyphase decomposition. to introduce the shift invariant gamma spline wavelet transform for tree structured subscale analysis of asymmetric signal waveforms and for systems with asymmetric impulse response. Especially we consider the applications in biomedical signal analysis (EEG, ECG, and EMG. Finally, we discuss the suitability of the gamma spline signal processing in embedded VLSI environment.

  18. GammaSem Proceedings. A Nordic seminar for users of gamma spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Straalberg, E. (ed.) (Institute for Energy Technolgy (Norway)); Berg, K. (National Institute of Radiation Protection (Denmark)); Dowdall, M. (Norwegian Radiation Protection Authority (Norway)) (and others)

    2010-11-15

    The project GammaSem was proposed to the NKS in 2008. The aim of the project was to arrange two seminars for users of gamma spectrometry, in 2009 and 2010. The seminars were meant to provide a forum for discussions and sharing of information on practical issues concerning gamma spectrometry and initiate a network of gamma spectrometry users in the Nordic countries. Such a Nordic network should strengthen the collaboration between laboratories and improve all participants' competence in practical gamma spectrometry. Both seminars' focus was practical challenges met by the users themselves, rather than theoretical matters. Scientists and users of gamma spectrometry from all five Nordic countries were invited to the seminar, as well as scientist from the Baltic countries. A total of 65 people signed up for GammaSem 2010; representing 30 different universities, commercial companies, research institutes and authorities. The working group concept as presented at last year's GammaSem, has not worked out as intended. The reason for this is probably because most of the laboratories that signed up to join the working groups, signed up because they wanted to learn more about the different subjects. In combination with the fact that no funding was made available for the working groups, it was difficult to establish goals on what to achieve. None of the working groups applied for funding from the NKS (or elsewhere) to establish separate projects. There is a big need for more cooperation and for training within the field of gamma spectrometry. This fact has been proved through these two seminars, both by the many different topics that have been discussed, but also by the huge interest for participating in the suggested series of workshop. The GammaSem seminars have thus provided a much welcomed starting point for a broader Nordic collaboration. (Author)

  19. GammaSem Proceedings. A Nordic seminar for users of gamma spectrometry

    International Nuclear Information System (INIS)

    Straelberg, E.; Berg, K.; Dowdall, M.

    2010-11-01

    The project GammaSem was proposed to the NKS in 2008. The aim of the project was to arrange two seminars for users of gamma spectrometry, in 2009 and 2010. The seminars were meant to provide a forum for discussions and sharing of information on practical issues concerning gamma spectrometry and initiate a network of gamma spectrometry users in the Nordic countries. Such a Nordic network should strengthen the collaboration between laboratories and improve all participants' competence in practical gamma spectrometry. Both seminars' focus was practical challenges met by the users themselves, rather than theoretical matters. Scientists and users of gamma spectrometry from all five Nordic countries were invited to the seminar, as well as scientist from the Baltic countries. A total of 65 people signed up for GammaSem 2010; representing 30 different universities, commercial companies, research institutes and authorities. The working group concept as presented at last year's GammaSem, has not worked out as intended. The reason for this is probably because most of the laboratories that signed up to join the working groups, signed up because they wanted to learn more about the different subjects. In combination with the fact that no funding was made available for the working groups, it was difficult to establish goals on what to achieve. None of the working groups applied for funding from the NKS (or elsewhere) to establish separate projects. There is a big need for more cooperation and for training within the field of gamma spectrometry. This fact has been proved through these two seminars, both by the many different topics that have been discussed, but also by the huge interest for participating in the suggested series of workshop. The GammaSem seminars have thus provided a much welcomed starting point for a broader Nordic collaboration. (Author)

  20. Gamma ray astronomy

    International Nuclear Information System (INIS)

    Fichtel, C.E.

    1975-01-01

    The first certain detection of celestial high energy gamma rays came from a satellite experiment flown on the third Orbiting Solar Observatory (OSO-111). A Gamma ray spark chamber telescope with substantively greater sensitivity and angular resolution (a few degrees) flown on the second Small Astronomy Satellite (SAS-II) has now provided a better picture of the gamma ray sky, and particularly the galactic plane and pulsars. This paper will summarize the present picture of gamma ray astronomy as it has developed at this conference from measurements made with experiments carried out on balloons, those remaining on the ground, and ones flown on satellites. (orig.) [de

  1. Getting Started for Preparing Pre-Service Early Childhood Teachers in Terms of Sustainable Food Consumption: The Current Situation at a Public University in Turkey

    Science.gov (United States)

    Alacam, Nur; Sahin, Elvan

    2017-01-01

    This study investigated the food consumption and nutrition perceptions of pre-service early childhood teachers using a mixed method research design. Data was gathered from 37 pre-service early childhood teachers through survey consisting of items in rating scale and open-ended questions. Descriptive analyses were conducted to report pre-service…

  2. A new search for primordial black hole evaporations using the Whipple gamma-ray telescope

    Science.gov (United States)

    Linton, E. T.; Atkins, R. W.; Badran, H. M.; Blaylock, G.; Boyle, P. J.; Buckley, J. H.; Byrum, K. L.; Carter-Lewis, D. A.; Celik, O.; Chow, Y. C. K.; Cogan, P.; Daniel, M. K.; Dowdall, C.; Falcone, A. D.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortin, P.; Guiterrez, K. J.; Hall, J.; Hanna, D.; Holder, J.; Horan, D.; Hughes, S. B.; Humensky, T. B.; Jung, I.; Kenny, G. E.; Kertzman, M.; Kieda, D. B.; Kildea, J.; Knapp, J.; Krawczynski, H.; Lang, M. J.; LeBohec, S.; Maier, G.; Moriarty, P.; Ong, R. A.; Perkins, J. S.; Pizlo, F.; Pohl, M.; Quinn, J.; Ragan, K.; Rebillot, P. F.; Reynolds, P. T.; Sembroski, G. H.; Steele, D.; Swordy, S. P.; Valcarcel, L.; Wakely, S. P.; Weekes, T. C.; White, R. J.

    2006-01-01

    Stephen Hawking's prediction that black holes should radiate like black bodies has several important consequences, including the possibility of the detection of small (~1015 g) black holes created in the very early universe. The detection of such primordial black holes (PBHs) would be an important discovery, not only confirming Hawking's theory, but also providing valuable insights into the history of the early universe. A search through 5.5 years of archival data from the Whipple Atmospheric Cerenkov Telescope is made for TeV gamma-ray bursts on 1, 3, and 5 s timescales. On the basis of a null result from this direct search for PBH evaporations, an upper limit of 1.08 × 106 pc-3 yr-1 (99% CL) is set on the PBH evaporation rate in the local region of the galaxy, assuming the Standard Model of particle physics. This is more than a factor of two better than the previous limit at this energy range and includes longer timescales than have previously been explored. Comparison of this result with previous limits on the fraction of the critical density comprised by PBHs, Ωpbh, depends strongly on assumptions made about PBH clustering; in models predicting strong PBH clustering, the limit in this work could be as many as ten orders of magnitude more stringently than those set by diffuse MeV gamma-ray observations.

  3. GRI: focusing on the evolving violent universe

    DEFF Research Database (Denmark)

    Knodlseder, J.; von Ballmoos, P.; Frontera, F.

    2009-01-01

    The gamma-ray imager (GRI) is a novel mission concept that will provide an unprecedented sensitivity leap in the soft gamma-ray domain by using for the first time a focusing lens built of Laue diffracting crystals. The lens will cover an energy band from 200-1,300 keV with an effective area reach...... processes in the universe....

  4. Gamma tomography apparatus

    International Nuclear Information System (INIS)

    Span, F.J.

    1988-01-01

    The patent concerns a gamma tomography apparatus for medical diagnosis. The apparatus comprises a gamma scintillation camera head and a suspension system for supporting and positioning the camera head with respect for the patient. Both total body scanning and single photon emission tomography can be carried out with the apparatus. (U.K.)

  5. Gamma-sterilization

    International Nuclear Information System (INIS)

    Lindgren, E.

    1974-01-01

    The author makes a survey of his experience in sterilization and sterility control of medical products. At present three different methods are used, steamsterilization, gassterilizing and gammasterilizing. The investments and costs for gamma radiation is presented and a comparison of the costs for gamma- and gassterilization including sterility control is made. (M.S.)

  6. Gamma-ray sources

    International Nuclear Information System (INIS)

    Hermsen, W.

    1980-01-01

    Results are presented from an analysis of the celestial gamma-ray fine-scale structure based on over half of the data which may ultimately be available from the COS-B satellite. A catalogue consisting of 25 gamma-ray sources measured at energies above 100 MeV is presented. (Auth.)

  7. Gamma ray astronomy

    International Nuclear Information System (INIS)

    Hillier, R.

    1984-01-01

    The book reviews the development of gamma ray astronomy over the past twenty five years. A large section of the book is devoted to the problems of background radiation and the design of detectors. Gamma rays from the sun, the galactic disc, the galaxy, and extra galactic sources; are also discussed. (U.K.)

  8. Promising mutant varieties of groundnut evolved through gamma irradiation

    International Nuclear Information System (INIS)

    Sinha, P.K.; Rahman, H.

    1980-01-01

    The Chotanagpur plateau region of Bihar is the main potential area for groundnut cultivation in the State. Var. AK 12-24 - an early, bunch type - has been the predominant variety under cultivation. Because of special nature of soil and rainfall pattern of this area, it is desirable to evolve a variety with early to mid-early maturity and bunch habit, but with improved yield potential over the ruling var. AK 12-24. Two bold podded mutants BP 1 and BP 2 were obtained throuo.h gamma irradiation of var 41-C which is a late maturing variety (135-140 days), spreading in habit and with medium kernel and pod size, whereas the mutant varieties have early (110-115 days for BP 1) to mid-early (115-120 days for BP 2) maturity, bunch habit and bold kernel and pods (HKW 55-60 gm for BP 1 and 60-66 gms for BP 2). Both have 20-25% higher yield potential over AK 12-24. The results of 3 years' yield evaluation trials at Kanke and one year minikit trials at different locations in Bihar show that BP 1 and BP 2 have significantly outyielded the check AK 12-24 and were at par with each other. Both varieties -because of their bold seededness - come under HPS type and have good export market. These varieties have now been released by the Rajendra Agricultural University as Sonya Bold 1 and Sonya Bold 2 for cultivation in Bihar. (author)

  9. Technology Needs for Gamma Ray Astronomy

    Science.gov (United States)

    Gehrels, Neil

    2011-01-01

    Gamma ray astronomy is currently in an exciting period of multiple missions and a wealth of data. Results from INTEGRAL, Fermi, AGILE, Suzaku and Swift are making large contributions to our knowledge of high energy processes in the universe. The advances are due to new detector and imaging technologies. The steps to date have been from scintillators to solid state detectors for sensors and from light buckets to coded aperture masks and pair telescopes for imagers. A key direction for the future is toward focusing telescopes pushing into the hard X-ray regime and Compton telescopes and pair telescopes with fine spatial resolution for medium and high energy gamma rays. These technologies will provide finer imaging of gamma-ray sources. Importantly, they will also enable large steps forward in sensitivity by reducing background.

  10. Improvement of rice starch by gamma irradiation

    International Nuclear Information System (INIS)

    Duan Zhiying; Wu Dianxing; Shen Shengquan; Han Juanying; Xia Yingwu

    2003-01-01

    Three types of rice cultivars, Indica, Japonica and hybrid rice, with similar intermediate apparent amylose content (AAC) as well as early Indica rice cultivars with different amounts of AAC were selected for studying the effects of gamma irradiation on starch viscosity, physico-chemical properties and starch granule structure. Four major parameters of RVA profile, peak viscosity (PKV), hot paste viscosity (HPV), cool paste viscosity (CPV), setback viscosity (SBV) and consistence viscosity (CSV) were considerably decreased with increasing dose levels. Gamma irradiation reduced the amylose contents in the cultivars with low AAC, intermediate AAC, and glutinous rice, but had no effects on the high AAC cultivar. No visible changes in alkali spreading value (ASV) were detected after irradiation, but the peak time (PKT) were reduced with the dose level. Gel consistency (GC) were significantly increased in the tested cultivars, especially in the high AAC Indica rice, suggesting that it is promising to use gamma irradiation to improve eating and cooking quality of rice

  11. Characterizing gamma fields using isomeric activation ratios

    Science.gov (United States)

    Venkataraman, Ramkumar; Fleming, Ronald F.

    1994-12-01

    Isomeric activities were induced in indium by gamma irradiation in three different gamma fields, through the reactions 115In(γ, γ') 115mIn and 113In(γ, γ') 113mIn. The irradiation fields were (i) the 15 kCi 60Co source available in the University, (ii) the spent fuel gamma irradiator in the pool of the University's Ford Nuclear Reactor (FNR) and (iii) south face of the core of the FNR during routine shut downs. Isomeric activation ratios can serve to characterize gamma fields, provided the response functions of the two (γ, γ') reactions sample different energy regimes of the gamma spectrum present in the irradiation fields. The response of an isomeric activation detector, in turn, depends on the number of activation energy levels of the nuclide and the probabilities with which the activation levels de-populate to the isomeric level. The reaction rate ratio RIn115m/ RIn113m was measured in the three gamma fields. The measured ratios were (i) 1.210 ± 0.011 in the 60Co source, (ii) 1.314 ± 0.060 in the spent fuel gamma irradiator and (iii) 1.298 ± 0.039 in a location alongside the FNR core during routine shut downs. The measured reaction rate ratios are not only close to each other, but close to unity as well. This indicates that the excitation functions for the reactions 115In(γ, γ') 115mIn and 113In(γ, γ') 113mIn have similar shapes and that for the nuclides 115In and 113In, the number of activation energy levels and the probabilities with which they populate the isomeric levels are very similar to each other. Thus, the ratio RIn115m/ RIn113m will not yield any information regarding the shape of gamma spectrum in the field of measurement. However by choosing (γ, γ') reactions with different shapes for the excitation functions one can measure a set of isomeric activation ratios that characterize a given gamma field.

  12. the Early Effects of Gamma radiation on the diurnal changes of Some Biochemical Parameters and the Role of α-lipoic acid as an Antioxidant in Male Albino rats

    International Nuclear Information System (INIS)

    Abdel-Fattah, K.I.; Yacoub, S.F.; Abdel-Aziz, N.

    2013-01-01

    In mammals most of the physiological and behavioral systems such as sleep-wake cycle, cardiovascular activity, endocrine system, blood pressure, body temperature and hepatic metabolism are regulated by the circadian clock. The aim of the present work was to investigate the disturbances induced after gamma irradiation on the metabolic diurnal rhythm and the role of α-alpha lipoic acid (ALA) in preventing/or decreasing these disorders in rat. Male Swiss albino rats were divided into 4 groups, one of which served as a normal control group, the second group was exposed to a single whole body gamma radiation dose of 6Gy, the third group was treated by gavage with ALA 100 mg/kg/day for 20 days and the fourth one was orally administered with ALA 100 mg/kg/day for 20 days before whole body gamma radiation at a dose of 6Gy. Rats were irradiated at 10 am and sacrificed at 11 am, 12 pm, 1 pm and 2 pm and then the biochemical analyses were performed. The results showed a significant increase in the level of lipid peroxidation products (MDA) at all time intervals. A significant increase was recorded also in the amount of free radicals at 11 am and 2 pm, and pyruvic acid level at 12 pm and 2 pm. A significant reduction of glutathione level (GSH) was recorded at 12 pm, 1 pm and 2 pm in the liver of the irradiated rats. Furthermore, a significant increase was registered in blood glucose level and blood aminotransferase activities (AST, ALT) in irradiated rats. Administration of ALA has significantly attenuated the radiation induced oxidative damage. It could be concluded that the biochemical changes induced by whole body gamma irradiation of rats are dependent on the circadian cycle. Further investigations are necessary to understand these complicated relations.

  13. GammaWorkshops Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ramebaeck, H. (ed.) (Swedish Defence Research Agency (Sweden)); Straalberg, E. (Institute for Energy Technology, Kjeller (Norway)); Klemola, S. (Radiation and Nuclear Safety Authority, STUK (Finland)); Nielsen, Sven P. (Technical Univ. of Denmark. Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Palsson, S.E. (Icelandic Radiation Safety Authority (Iceland))

    2012-01-15

    Due to a sparse interaction during the last years between practioners in gamma ray spectrometry in the Nordic countries, a NKS activity was started in 2009. This GammaSem was focused on seminars relevant to gamma spectrometry. A follow up seminar was held in 2010. As an outcome of these activities it was suggested that the 2011 meeting should be focused on practical issues, e.g. different corrections needed in gamma spectrometric measurements. This three day's meeting, GammaWorkshops, was held in September at Risoe-DTU. Experts on different topics relevant for gamma spectrometric measurements were invited to the GammaWorkshops. The topics included efficiency transfer, true coincidence summing corrections, self-attenuation corrections, measurement of natural radionuclides (natural decay series), combined measurement uncertainty calculations, and detection limits. These topics covered both lectures and practical sessions. The practical sessions included demonstrations of tools for e.g. corrections and calculations of the above meantioned topics. (Author)

  14. Application of low-dose gamma irradiation to extend the shelf life of minimally processed Red Beet (Beta vulgaris sp. vulgaris L.), cv. Early Wonder; Aplicacao de baixas doses de radiacao gama para extensao da vida util de beterraba vermelha (Beta vulgaris ssp. vulgaris L.), cv. Early Wonder, minimamente processada

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, Nilber Kenup

    2006-07-01

    This study was aimed at investigating the effects of low-dose gamma irradiation on shelf-life extension and phyto sanitary safety of minimally processed red beet with basis on physicochemical; microbiological; chemical and sensory analyses. The samples (Beta vulgaris ssp. vulgaris L.), Early Wonder cultivar, were cultivated in the experimental area of the Horticulture Sector of the Departamento de Fitotecnia of the Instituto de Agronomia, Universidade Federal Rural do Rio de Janeiro, Seropedica, RJ, as part of two experiments performed during the second semester of 2005. In each experiment, 1200 plants (40 per linear meter of terrain) were sowed. Physicochemical analyses (fresh mass; length; average diameter and total soluble solids) of the edible part of the red beets (their tuberous roots) were periodically carried out in order to assess the most appropriate time for harvest by monitoring the development of the plants. Those times were found to be 104 and 73 days after transplanting, respectively. The harvested edible part of the roots were minimally processed and separated in two groups: (1) gamma irradiated (with doses of 0.5; 1.0 and 1.5 kGy) and (2) non-irradiated (control). All samples were stored at 8 degree C. Microbiological analyses were performed during the storage period (22 and 21 days, for experiments 1 and 2, respectively) in order to evaluate the phyto sanitary quality of the samples (Salmonella sp.; coliforms and total count of mesophilic aerobic and lactic acid bacteria). The samples irradiated with 1.0 and 1.5 kGy were found to remain appropriate for consumption for 21 days, as compared to only 7 days for the control. Monitoring of chemical composition was also performed and included the determination of saccharose; glucose; fructose and vitamins B1 and B2. No difference was found between the concentrations of those vitamins in irradiated and control samples at the end of the storage period, whereas significant changes in sugar contents were

  15. The gamma function

    CERN Document Server

    Artin, Emil

    2015-01-01

    This brief monograph on the gamma function was designed by the author to fill what he perceived as a gap in the literature of mathematics, which often treated the gamma function in a manner he described as both sketchy and overly complicated. Author Emil Artin, one of the twentieth century's leading mathematicians, wrote in his Preface to this book, ""I feel that this monograph will help to show that the gamma function can be thought of as one of the elementary functions, and that all of its basic properties can be established using elementary methods of the calculus."" Generations of teachers

  16. Investigation of Electricity Generation by Using Gamma Radiation from Spent Fuels

    International Nuclear Information System (INIS)

    Lee, Haneol; Yim, Man-Sung Yim

    2015-01-01

    The purpose of this study is to investigate the electric power generation with scale spent fuel. OrigenArp has analyzed gamma radiation environment of spent fuel assembly, MCNPX has analyzed the scintillator behavior, and experimental work has analyzed the electric output of photovoltaic cell. Gamma radiation environment analysis result indicates gamma source rapidly decreases for the early storage period. Scintillator analysis result calculates the photon flux distribution which enters photovoltaic cell. Photovoltaic cell experiment calculates electric current, voltage current generation per each system unit. Generated electric power can be used to cope with existing safety system (i.e. storage monitoring system) under severe accident or to operate security system under external invasion situation (i.e. passive physical barrier system). Several researchers have shown that converting radiation energy into electric energy is possible. Karl Scharf studied the direct electric conversion of radiation energy by using photovoltaic cells. Researchers in University of Massachusetts Lowell have studied radiation-electric energy conversion by using gadolinium oxide scintillator and dye sensitized solar cell (DSSCs) and N. Horuichi et al. studied radiation-electric energy conversion by using inorganic scintillators and amorphous and crystal photovoltaic cells

  17. The inflationary universe

    International Nuclear Information System (INIS)

    Linde, A.D.

    1984-01-01

    According to the inflationary universe scenario the universe in the very early stages of its evolution was exponentially expanding in the unstable vacuum-like state. At the end of the exponential expansion the energy of the unstable vacuum transforms into the energy of hot dense matter. Recently it was realised that the exponential expansion of the universe naturally occurs in a wide class of realistic theories of elementary particles. The inflationary universe scenario makes it possible to obtain a simple solution to many longstanding cosmological problems and leads to a crucial modification of the standard point of view of the large-scale structure of the universe. (author)

  18. The universe a biography

    CERN Document Server

    Gribbin, John

    2008-01-01

    The Universe: A Biography makes cosmology accessible to everyone. John Gribbin navigates the latest frontiers of scientific discovery to tell us what we really know about the history of the universe. Along the way, he describes how the universe began; what the early universe looked like; how its structure developed; and what emerged to hold it all together. He describes where the elements came from; how stars and galaxies formed; and the story of how life emerged. He even looks to the future: is the history of the universe going to end with a Big Crunch or a Big Rip.

  19. GammaSem Proceedings - A Nordic seminar for users of gamma spectrometry

    International Nuclear Information System (INIS)

    Nunez, P.; Klemola, S.; Nielsen, Sven P.; Palsson, S.E.; Israelson, C.

    2010-03-01

    The project GammaSem was proposed to provide a forum for discussions and sharing of information on practical issues concerning gamma spectrometry and to establish a network of users of gamma spectrometry in the Nordic countries, thereby strengthening the collaboration and improving all participants' competence in practical gamma spectrometry. The seminars' focus was practical challenges met by the users themselves, rather than theoretical matters. Scientists and users of gamma spectrometry from all five Nordic countries were invited to the seminar, as well as scientist from the Baltic countries. A total of 75 people participated; representing 34 different universities, commercial companies, research institutes and also all Nordic authorities. During the seminar several key issues for follow-up were identified and working groups for addressing the identified problems were established. The working groups were: 1) Uncertainties and detections of limits 2) True summing coincidence 3) Monte Carlo simulations and efficiency transfer 4) Absorption (density corrections and geometries) 5) Mobile gamma spectrometry systems 6) Nuclear forensics (on special samples and special parts of the spectra). The identified topics will form the basis for the agenda of the next seminar in 2010. There, the different working groups will be invited to present their ideas/solutions to the relevant problems. (author)

  20. GammaSem Proceedings - A Nordic seminar for users of gamma spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, P. (ed.) (Institute for Energy Technology (IFE) (Norway)); Klemola, S. (Radiation and Nuclear Safety Authority (STUK) (Finland)); Nielsen, Sven P. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy. Roskilde (Denmark)); Palsson, S.E. (Icelandic Radiation Safety Authority (IS)); Israelson, C. (National Institute of Radiation Protection (Denmark))

    2010-03-15

    The project GammaSem was proposed to provide a forum for discussions and sharing of information on practical issues concerning gamma spectrometry and to establish a network of users of gamma spectrometry in the Nordic countries, thereby strengthening the collaboration and improving all participants' competence in practical gamma spectrometry. The seminars' focus was practical challenges met by the users themselves, rather than theoretical matters. Scientists and users of gamma spectrometry from all five Nordic countries were invited to the seminar, as well as scientist from the Baltic countries. A total of 75 people participated; representing 34 different universities, commercial companies, research institutes and also all Nordic authorities. During the seminar several key issues for follow-up were identified and working groups for addressing the identified problems were established. The working groups were: 1) Uncertainties and detections of limits 2) True summing coincidence 3) Monte Carlo simulations and efficiency transfer 4) Absorption (density corrections and geometries) 5) Mobile gamma spectrometry systems 6) Nuclear forensics (on special samples and special parts of the spectra). The identified topics will form the basis for the agenda of the next seminar in 2010. There, the different working groups will be invited to present their ideas/solutions to the relevant problems. (author)