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Sample records for early universe carbon

  1. Water Emission from Early Universe

    NASA Astrophysics Data System (ADS)

    Jarugula, Sreevani; Vieira, Joaquin

    2017-06-01

    The study of dusty star forming galaxies (DSFGs) is important to understand galaxy assembly in early universe. A bulk of star formation at z ˜ 2-3 takes place in DSFGs but are obscured by dust in optical/UV. However, they are extremely bright in far infrared (FIR) and submillimeter with infrared luminosities of 10^{11} - 10^{13} L_{⊙}. ALMA, with its high spatial and spectral resolution, has opened up a new window to study molecular lines, which are vital to our understanding of the excitation and physical processes in the galaxy. Carbon monoxide (CO) being the second most abundant and bright molecule after hydrogen (H_{2}), is an important tracer of star forming potential. Besides CO, water (H_{2}O) is also abundant and it's line strength is comparable to high-J CO lines in high redshift Ultra Luminous Infrared Galaxies (ULIRGs). Studies have shown H_{2}O to directly trace the FIR field and hence the star forming regions. Moreover, L_{H_{2}O}/L_{IR} ratio is nearly constant for five of the most important water lines and does not depend on the presence of AGN implying that H_{2}O is one of the best tracers of star forming regions (SFRs). This incredible correlation holds for nearly five orders of magnitude in luminosity and observed in both local and high redshift luminous infrared galaxies. In this talk, I will discuss the importance of H_{2}O in tracing FIR field and show the preliminary results of resolved water emission from three high-redshift gravitationally lensed South Pole Telescope (SPT) sources obtained from ALMA cycle 3 and cycle 4. These sources are among the first H_{2}O observations with resolved spatial scales ˜ 1 kpc and will prove to be important for ALMA and galaxy evolution studies.

  2. Carbon in the Universe

    NASA Technical Reports Server (NTRS)

    Allamandola, Louis J.

    2013-01-01

    Over the past few decades, NASA missions have revealed that we live in a Universe that is not a hydrogen-dominated, physicist's paradise, but in a molecular Universe with complex molecules directly interwoven into its fabric. These missions have shown that molecules are an abundant and important component of astronomical objects at all stages of their evolution and that they play a key role in many processes that dominate the structure and evolution of galaxies. Closer to home in our galaxy, the Milky Way, they have revealed a unique and complex organic inventory of regions of star and planet formation that may well represent some of the prebiotic roots to life. Astrobiology emerges from the great interest in understanding astrochemical evolution from simple to complex molecules, especially those with biogenic potential and the roles they may play as primordial seeds in the origin of life on habitable worlds. The first part of this talk will highlight how infrared spectroscopic studies of interstellar space, combined with dedicated laboratory simulations, have revealed the widespread presence of complex organics across deep space. The remainder of the presentation will focus on the evolution of these materials and astrobiology.

  3. Shocks in the Early Universe.

    PubMed

    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.

  4. Inflation in the early universe.

    NASA Astrophysics Data System (ADS)

    Carmeli, M.

    1998-04-01

    In this talk it will be assumed that gravitation is negligible. Under this assumption, the receding velocities of galaxies and the distances between them in the Hubble expansion are united into a four-dimensional pseudo-Euclidean manifold, similarly to space and time in ordinary special relativity. The Hubble law is assumed and is written in an invariant way that enables one to derive a four-dimensional transformation which is similar to the Lorentz transformation. The parameter in the new transformation is the ratio between the cosmic time to the Hubble time. Accordingly, the new transformation relates physical quantities at different cosmic times in the limit of weak or negligible gravitation. The transformation is then applied to the problem of the expansion of the Universe at the very early stage when gravity was negligible and thus the transformation is applicable. The author calculates the ratio of the volumes of the Universe at two different times T1 and T2 after the big bang. The result conforms with the standard inflationary universe theory, but now it is obtained without assuming that the Universe is propelled by antigravity.

  5. Cosmology and the early universe

    NASA Astrophysics Data System (ADS)

    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.

  6. Inflation in the Early Universe

    NASA Astrophysics Data System (ADS)

    Carmeli, Moshe

    In this talk it will be assumed that gravitation is negligible. Under this assumption, the receding velocities of galaxies and the distances between them in the Hubble expansion are united into a four-dimensional pseudo-Euclidean manifold, similarly to space and time in ordinary special relativity. The Hubble law is assumed and is written in an invariant way that enables one to derive a four-dimensional transformation which is similar to the Lorentz transformation. The parameter in the new transformation is the ratio between the cosmic time to the Hubble time (in which the cosmic time is measured backward with respect to the present time). Accordingly, the new transformation relates physical quantities at different cosmic times in the limit of weak or negligible gravitation. The transformation is then applied to the problem of the expansion of the Universe at the very early stage when gravity was negligible and thus the transformation is applicable. We calculate the ratio of the volumes of the Universe at two different times T1 and T2 after the Big Bang. Under the assumptions that T2 - T1 ≈ 10-32 sec and T2 ≪ 1 sec, we find that V_{2}/V_{1} = 10^{-16}/√{T_{1}}. For T1 ≈ 10-132 sec we obtain V2/V1 ≈ 1050. This result conforms with the standard inflationary universe theory, but now it is obtained without assuming that the Universe is propelled by antigravity.

  7. Artist's Concept of Early Universe

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is an artist's impression of how the very early universe (less than one billion years old) might have looked when it went through a voracious onset of star formation, converting primordial hydrogen into myriad stars at an unprecedented rate. The deepest views of the cosmos from the Hubble Space Telescope (HST) yield clues that the very first stars may have burst into the universe as brilliantly and spectacularly as a firework finale. Except in this case, the finale came first, long before Earth, the Sun ,and the Milky Way Galaxy formed. Studies of HST's deepest views of the heavens lead to the preliminary conclusion that the universe made a significant portion of its stars in a torrential firestorm of star birth, which abruptly lit up the pitch-dark heavens just a few hundred million years after the 'big bang,' the tremendous explosion that created the cosmos. Within the starburst galaxies, bright knots of hot blue stars come and go like bursting fireworks shells. Regions of new starbirth glow intensely red under torrent of ultraviolet radiation. The most massive stars self-detonate as supernovas, which explode across the sky like a string of firecrackers. A foreground starburst galaxy at lower right is sculpted with hot bubbles from supernova explosions and torrential stellar winds. Unlike today there is very little dust in these galaxies, because the heavier elements have not yet been cooked up through nucleosynthesis in stars. Recent analysis of HST deep sky images supports the theory that the first stars in the universe appeared in an abrupt eruption of star formation, rather than at a gradual pace. Science Credit: NASA and K. Lanzetta (SUNY). Artwork Credit: Adolf Schaller for STScI.

  8. The Early Retirees of Canadian Universities.

    ERIC Educational Resources Information Center

    Jefferson, Anne L.

    Because an option for early retirement in Canadian Universities has created a need to know more about the vacancies early retirement creates and the potential to fill these vacancies, a survey of 15 representative universities was conducted. The sample included institutions of faculty numbering less than 100 to institutions of faculty numbering…

  9. WMAP - A Glimpse of the Early Universe

    NASA Technical Reports Server (NTRS)

    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.

  10. Disorder in the early universe

    SciTech Connect

    Green, Daniel, E-mail: drgreen@cita.utoronto.ca

    2015-03-01

    Little is known about the microscopic physics that gave rise to inflation in our universe. There are many reasons to wonder if the underlying description requires a careful arrangement of ingredients or if inflation was the result of an essentially random process. At a technical level, randomness in the microphysics of inflation is closely related to disorder in solids. We develop the formalism of disorder for inflation and investigate the observational consequences of quenched disorder. We find that a common prediction is the presence of additional noise in the power spectrum or bispectrum. At a phenomenological level, these results canmore » be recast in terms of a modulating field, allowing us to write the quadratic maximum likelihood estimator for this noise. Preliminary constraints on disorder can be derived from existing analyses but significant improvements should be possible with a dedicated treatment.« less

  11. Particle physics in the very early universe

    NASA Technical Reports Server (NTRS)

    Schramm, D. N.

    1981-01-01

    Events in the very early big bang universe in which elementary particle physics effects may have been dominant are discussed, with attention to the generation of a net baryon number by way of grand unification theory, and emphasis on the possible role of massive neutrinos in increasing current understanding of various cosmological properties and of the constraints placed on neutrino properties by cosmology. It is noted that when grand unification theories are used to describe very early universe interactions, an initially baryon-symmetrical universe can evolve a net baryon excess of 10 to the -9th to 10 to the -11th per photon, given reasonable parameters. If neutrinos have mass, the bulk of the mass of the universe may be in the form of leptons, implying that the form of matter most familiar to physical science may not be the dominant form of matter in the universe.

  12. The Toy model: Understanding the early universe

    NASA Astrophysics Data System (ADS)

    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.

  13. Carbon dioxide warming of the early Earth

    NASA Technical Reports Server (NTRS)

    Arrhenius, G.

    1997-01-01

    Svante Arrhenius' research in atmospheric physics extended beyond the recent past and the near future states of the Earth, which today are at the center of sociopolitical attention. His plan encompassed all of the physical phenomena known at the time to relate to the formation and evolution of stars and planets. His two-volume textbook on cosmic physics is a comprehensive synopsis of the field. The inquiry into the possible cause of the ice ages and the theory of selective wavelength filter control led Arrhenius to consider the surface states of the other terrestrial planets, and of the ancient Earth before it had been modified by the emergence of life. The rapid escape of hydrogen and the equilibration with igneous rocks required that carbon in the early atmosphere prevailed mainly in oxidized form as carbon dioxide, together with other photoactive gases exerting a greenhouse effect orders of magnitude larger than in our present atmosphere. This effect, together with the ensuing chemical processes, would have set the conditions for life to evolve on our planet, seeded from spores spreading through an infinite Universe, and propelled, as Arrhenius thought, by stellar radiation pressure.

  14. Carbon dioxide warming of the early Earth.

    PubMed

    Arrhenius, G

    1997-02-01

    Svante Arrhenius' research in atmospheric physics extended beyond the recent past and the near future states of the Earth, which today are at the center of sociopolitical attention. His plan encompassed all of the physical phenomena known at the time to relate to the formation and evolution of stars and planets. His two-volume textbook on cosmic physics is a comprehensive synopsis of the field. The inquiry into the possible cause of the ice ages and the theory of selective wavelength filter control led Arrhenius to consider the surface states of the other terrestrial planets, and of the ancient Earth before it had been modified by the emergence of life. The rapid escape of hydrogen and the equilibration with igneous rocks required that carbon in the early atmosphere prevailed mainly in oxidized form as carbon dioxide, together with other photoactive gases exerting a greenhouse effect orders of magnitude larger than in our present atmosphere. This effect, together with the ensuing chemical processes, would have set the conditions for life to evolve on our planet, seeded from spores spreading through an infinite Universe, and propelled, as Arrhenius thought, by stellar radiation pressure.

  15. WMAP - A Portrait of the Early Universe

    NASA Technical Reports Server (NTRS)

    Wollack, Edward J.

    2008-01-01

    A host of astrophysical observations suggest that 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, constraints on the age, mass density, and geometry of the early Universe can be derived. A brief history of the evolution of the microwave radiometer systems and map making approaches used in advancing these aspects our understanding of cosmological will be reviewed. In addition, an overview of the results from NASA's Wilkinson Microwave Anisotropy (WMAP) will be presented.

  16. DMR 'Map of the Early Universe.'

    NASA Technical Reports Server (NTRS)

    2002-01-01

    DMR 'Map of the Early Universe.' This false-color image shows tiny variations in the intensity of the cosmic microwave background measured in four years of observations by the Differential Microwave Radiometers on NASA's Cosmic Background Explorer (COBE). The cosmic microwave background is widely believed to be a remnant of the Big Bang; the blue and red spots correspond to regions of greater or lesser density in the early Universe. These 'fossilized' relics record the distribution of matter and energy in the early Universe before the matter became organized into stars and galaxies. While the initial discovery of variations in the intensity of the CMB (made by COBE in 1992) was based on a mathematical examination of the data, this picture of the sky from the full four-year mission gives an accurate visual impression of the data. The features traced in this map stretch across the visible Universe: the largest features seen by optical telescopes, such as the 'Great Wall' of galaxies, would fit neatly within the smallest feature in this map. (See Bennett et al. 1996, ApJ, 464, L1 and references therein for details.)

  17. QCD development in the early universe

    SciTech Connect

    Gromov, N. A., E-mail: gromov@dm.komisc.ru

    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.

  18. Protostar formation in the early universe.

    PubMed

    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.

  19. A universal model for nanoporous carbon supercapacitors

    SciTech Connect

    Huang, Jingsong; Sumpter, Bobby G; Meunier, Vincent

    2009-01-01

    Supercapacitors based on nanoporous carbon materials, commonly called electric double-layer capacitors (EDLCs), are emerging as a novel type of energy-storage device with the potential to substitute batteries in applications that require high power densities. Nanoporous carbon supercapacitors are generally viewed as a parallel-plate capacitor since supercapacitors store energy by charge separation in an electric double layer formed at the electrode/electrolyte interface. The EDLC model has been used to characterize the energy storage of supercapacitors for decades. We comment in this chapter on the shortcomings of the EDLC model when applied to nanoporous carbon supercapacitors. In response to the latest experimentalmore » breakthrough in nanoporous carbon supercapacitors, we have proposed a heuristic model that takes pore curvature into account as a replacement for the EDLC model. When the pore size is in the mesopore regime (2 50 nm), electrolyte counterions enter mesoporous carbons and approach the pore wall to form an electric double-cylinder capacitor (EDCC); in the micropore regime (< 2 nm), solvated/desolvated counterions line up along the pore axis to form an electric wire-in-cylinder capacitor (EWCC). In the macropore regime (> 50 nm), where pores are large enough so that pore curvature is no longer significant, the EDCC model can be reduced to the EDLC model. With the backing of experimental data and quantum density functional theory calculations, we have shown that the EDCC/EWCC model is universal for carbon supercapacitors with diverse carbon materials and electrolytes. The strengths and limitations of this new model are discussed. The new model allows the supercapacitor properties to be correlated with pore size, specific surface area, Debye length, electrolyte concentration, dielectric constant, and solute ion size, and may lend support to the systematic optimization of the properties of carbon supercapacitors through experiments.« less

  20. Forming Disk Galaxies Early in the Universe

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-08-01

    What were galaxies like in the first 500 million years of the universe? According to simulations by Yu Feng (UC Berkeley) and collaborators, the earliest massive galaxies to form were mostly disk-shaped, rather than the compact clumps previously predicted. Early-Galaxy Models. Current models for galaxy formation predict that small perturbations in the distribution of matter in the early universe collapsed to form very compact, irregular, clumpy first galaxies. Observations support this: the furthest out that we've spotted disk-shaped galaxies is at z=3, whereas the galaxies we've observed from earlier times -- up to redshifts of z=8-10 -- are very compact. But could this be a selection effect, arising from the rarity of large galaxies in the early universe? Current surveys at high redshift have thus far only covered relatively small volumes of space, so it's not necessarily surprising that we haven't yet spotted any large disk galaxies. Similarly, numerical simulations of galaxy formation are limited in the size of the volume they can evolve, so resulting models of early galaxy formation also tend to favor compact clumpy galaxies over large disks. An Enormous Simulation. Pushing at these limitations, Feng and his collaborators used the Blue Waters supercomputer to carry out an enormous cosmological hydrodynamic simulation called BlueTides. In this simulation, they track 700 billion particles as they evolve in a volume of 400 comoving Mpc/h -- 40 times the volume of the largest previous simulation and 300 times the volume of the largest observational survey at these redshifts. What they find is that by z=8, a whopping 70% of the most massive galaxies (over 7 billion solar masses each) were disk-shaped, though they are more compact, gas-rich, and turbulent than present-day disk galaxies like the Milky Way. The way the most massive galaxies formed in the simulation also wasn't expected: rather than resulting from major mergers, they were built from smooth accretion

  1. Exploring the Early Universe on Mobile Devices

    NASA Astrophysics Data System (ADS)

    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.

  2. ALICE in the early Universe wonderland

    NASA Astrophysics Data System (ADS)

    Di Nezza, Pasquale

    2012-03-01

    In these years the Large Hadron Collider (LHC) at CERN is probing, for the first time, physics at energy scales more than an order of magnitude beyond that of the Standard Model. These experiments explore an energy regime of particle physics where phenomena, such as supersymmetry and Grand Unified Theories, may become relevant. Certainly, the LHC should shed light on the mechanism of electroweak symmetry breaking and may discover the first fundamental scalar particle seen in nature. The collisions of heavy ions (Pb - Pb) will create the same "soup" the early Universe had at the epoch of 10-5 seconds. In general, there is a strong and growing interplay between particle physics and cosmology, in particular in the possible production of mini black holes and dark matter candidates like the lightest neutralino in the MSSM.

  3. Cosmological Simulations with Molecular Astrochemistry: Water in the Early Universe

    NASA Astrophysics Data System (ADS)

    Wiggins, Brandon K.; Smidt, Joseph

    2018-01-01

    Water is required for the rise of life as we know it throughout the universe, but its origin and the circumstances of its first appearance remain a mystery. The abundance of deuterated water in solar system bodies cannot be explained if all the water in the solar system were created in the protoplanetary disk (Cleeves et al. 2014), suggesting that as much of half of Earth’s water predates the Sun. Water has been observed as early as one sixth the current universe’s age in MG J0414+0534 (Imprellizzeri et al. 2008). It was recently shown that water could, in principle, appear in hot halos barely enriched with heavy elements such as oxygen and carbon (Bialy et al. 2015). So far, no self-consistent calculation of cosmology physics carried out in line with a large chemical reaction network has been carried out to study the first sites of water formation in the universe. We present initial results the first such series of cosmological calculations with a 26 species low metallicity molecular chemical reaction network with Enzo (Bryan et al. 2014) to understand the role of hydrodynamics and radiative feedback on molecule formation in the early universe and to shed light on the cosmological history of this life-giving substance.

  4. Nuclear matter in the early universe

    SciTech Connect

    Barros, Celso de Camargo, E-mail: barros.celso@ufsc.br; Cunha, Ivan Eugênio da, E-mail: lordlihige@hotmail.com

    Recently, extreme conditions have been obtained in ultra-relativistic heavy ion collisions at RHIC and at the Large Hadron collider. It is believed that these conditions are similar to the ones of the early Universe, in the time between 10{sup −6}s and 1s, approximately. In this work, the hadrons produced in this range of time will be studied, considering some aspects of the systems produced in the heavy-ion collisions. We will study a phase posterior to the phase transition (in fact it is believed to be a crossover) from the quark-gluon plasma, that is the hadronic phase of the Universe. Wemore » will show the model proposed in [1], considering the hadronic matter described by a relativistic model (similar to the Walecka model), considering particles described by quantum equations in a curved spacetime. This curvature is due to the mass and to the strong interactions that appears in the energy-momentum tensor. The set of the equations is proposed in the Robertson-Walker metric, and some approximate solutions are obtained.« less

  5. Galactic Pairs in the Early Universe

    NASA Astrophysics Data System (ADS)

    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

  6. The Early Astronomy Toolkit was Universal

    NASA Astrophysics Data System (ADS)

    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

  7. Elementary particles in the early Universe

    SciTech Connect

    Gromov, N.A., E-mail: gromov@dm.komisc.ru

    The high-temperature limit of the Standard Model generated by the contractions of gauge groups is discussed. Contraction parameters of gauge group SU(2) of the Electroweak Model and gauge group SU(3) of Quantum Chromodynamics are taken identical and tending to zero when the temperature increases. Properties of the elementary particles change drastically at the infinite temperature limit: all particles lose masses, all quarks are monochromatic. Electroweak interactions become long-range and are mediated by neutral currents. Particles of different kind do not interact. It looks like some stratification with only one sort of particles in each stratum. The Standard Model passes inmore » this limit through several stages, which are distinguished by the powers of the contraction parameter. For any stage intermediate models are constructed and the exact expressions for the respective Lagrangians are presented. The developed approach describes the evolution of the Standard Model in the early Universe from the Big Bang up to the end of several nanoseconds.« less

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

    NASA Astrophysics Data System (ADS)

    Rafelski, Johann

    2013-10-01

    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.

  9. The emergence and early evolution of biological carbon-fixation.

    PubMed

    Braakman, Rogier; Smith, Eric

    2012-01-01

    The fixation of CO₂ into living matter sustains all life on Earth, and embeds the biosphere within geochemistry. The six known chemical pathways used by extant organisms for this function are recognized to have overlaps, but their evolution is incompletely understood. Here we reconstruct the complete early evolutionary history of biological carbon-fixation, relating all modern pathways to a single ancestral form. We find that innovations in carbon-fixation were the foundation for most major early divergences in the tree of life. These findings are based on a novel method that fully integrates metabolic and phylogenetic constraints. Comparing gene-profiles across the metabolic cores of deep-branching organisms and requiring that they are capable of synthesizing all their biomass components leads to the surprising conclusion that the most common form for deep-branching autotrophic carbon-fixation combines two disconnected sub-networks, each supplying carbon to distinct biomass components. One of these is a linear folate-based pathway of CO₂ reduction previously only recognized as a fixation route in the complete Wood-Ljungdahl pathway, but which more generally may exclude the final step of synthesizing acetyl-CoA. Using metabolic constraints we then reconstruct a "phylometabolic" tree with a high degree of parsimony that traces the evolution of complete carbon-fixation pathways, and has a clear structure down to the root. This tree requires few instances of lateral gene transfer or convergence, and instead suggests a simple evolutionary dynamic in which all divergences have primary environmental causes. Energy optimization and oxygen toxicity are the two strongest forces of selection. The root of this tree combines the reductive citric acid cycle and the Wood-Ljungdahl pathway into a single connected network. This linked network lacks the selective optimization of modern fixation pathways but its redundancy leads to a more robust topology, making it more

  10. A Universal Early Childhood Education System

    ERIC Educational Resources Information Center

    Brown, Christopher P.

    2006-01-01

    In this article, the author demonstrates how the current emphasis on viewing early childhood education (ECE) as an investment keeps ECE at the margins of U.S. political debates as well as in other discussions around the world. Historically, the field of ECE in the United States has struggled, and continues to struggle, for political positioning.…

  11. Assessing Carbon Dioxide Emissions from Energy Use at a University

    ERIC Educational Resources Information Center

    Riddell, William; Bhatia, Krishan Kumar; Parisi, Matthew; Foote, Jessica; Imperatore, John, III

    2009-01-01

    Purpose: The purpose of this paper is to assess the carbon dioxide emissions associated with electric, HVAC, and hot water use from a US university. Design/methodology/approach: First, the total on-campus electrical, natural gas and oil consumption for an entire year was assessed. For each category of energy use, the carbon associated with…

  12. Numerical relativity and the early Universe

    NASA Astrophysics Data System (ADS)

    Mironov, Sergey

    2016-10-01

    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.

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

    ERIC Educational Resources Information Center

    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…

  14. Using Supercomputers to Probe the Early Universe

    SciTech Connect

    Giorgi, Elena Edi

    For decades physicists have been trying to decipher the first moments after the Big Bang. Using very large telescopes, for example, scientists scan the skies and look at how fast galaxies move. Satellites study the relic radiation left from the Big Bang, called the cosmic microwave background radiation. And finally, particle colliders, like the Large Hadron Collider at CERN, allow researchers to smash protons together and analyze the debris left behind by such collisions. Physicists at Los Alamos National Laboratory, however, are taking a different approach: they are using computers. In collaboration with colleagues at University of California San Diego,more » the Los Alamos researchers developed a computer code, called BURST, that can simulate conditions during the first few minutes of cosmological evolution.« less

  15. Black hole formation in the early Universe

    NASA Astrophysics Data System (ADS)

    Latif, M. A.; Schleicher, D. R. G.; Schmidt, W.; Niemeyer, J.

    2013-08-01

    Supermassive black holes with up to a 109 M⊙ dwell in the centres of present-day galaxies, and their presence has been confirmed at z ≥ 6. Their formation at such early epochs is still an enigma. Different pathways have been suggested to assemble supermassive black holes in the first billion years after the big bang. Direct collapse has emerged as a highly plausible scenario to form black holes as it provides seed masses of 105-106 M⊙. Gravitational collapse in atomic cooling haloes with virial temperatures Tvir ≥ 104 K may lead to the formation of massive seed black holes in the presence of an intense background ultraviolet flux. Turbulence plays a central role in regulating accretion and transporting angular momentum. We present here the highest resolution cosmological large eddy simulations to date which track the evolution of high-density regions on scales of 0.25 au beyond the formation of the first peak, and study the impact of subgrid-scale turbulence. The peak density reached in these simulations is 1.2 × 10-8 g cm-3. Our findings show that while fragmentation occasionally occurs, it does not prevent the growth of a central massive object resulting from turbulent accretion and occasional mergers. The central object reaches ˜1000 M⊙ within four free-fall times, and we expect further growth up to 106 M⊙ through accretion in about 1 Myr. The direct collapse model thus provides a viable pathway of forming high-mass black holes at early cosmic times.

  16. Black holes in the early Universe.

    PubMed

    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.

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

    ERIC Educational Resources Information Center

    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. 3D climate-carbon modelling of the early Earth

    NASA Astrophysics Data System (ADS)

    Charnay, B.; Le Hir, G.; Fluteau, F.; Forget, F.; Catling, D.

    2017-09-01

    We revisit the climate and carbon cycle of the early Earth at 3.8 Ga using a 3D climate-carbon model. Our resultsfavor cold or temperate climates with global mean temperatures between around 8°C (281 K) and 30°C (303 K) and with 0.1-0.36 bar of CO2 for the late Hadean and early Archean.

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

    ERIC Educational Resources Information Center

    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…

  20. COBE - New sky maps of the early universe

    NASA Technical Reports Server (NTRS)

    Smoot, G. F.

    1991-01-01

    This paper presents early results obtained from the first six months of measurements of the cosmic microwave background (CMB) by instruments aboard NASA's Cosmic Background Explorer (COBE) satellite and discusses the implications for cosmology. The three instruments: FIRAS, DMR, and DIRBE have operated well and produced significant new results. The FIRAS measurement of the CMB spectrum supports the standard big bang nucleosynthesis model. The maps made from the DMR instrument measurements show a surprisingly smooth early universe. The measurements are sufficiently precise that we must pay careful attention to potential systematic errors. The maps of galactic and local emission produced by the DIRBE instrument will be needed to identify foregrounds from extragalactic emission and thus to interpret the terms of events in the early universe.

  1. Carbon storage and sequestration by trees in VIT University campus

    NASA Astrophysics Data System (ADS)

    Saral, A. Mary; SteffySelcia, S.; Devi, Keerthana

    2017-11-01

    The present study addresses carbon storage and sequestration by trees grown in VIT University campus, Vellore. Approximately twenty trees were selected from Woodstockarea. The above ground biomass and below ground biomass were calculated. The above ground biomass includes non-destructive anddestructive sampling. The Non-destructive method includes the measurement of height of thetree and diameter of the tree. The height of the tree is calculated using Total Station instrument and diameter is calculated using measuring tape. In the destructive method the weight of samples (leaves) and sub-samples (fruits, flowers) of the tree were considered. To calculate the belowground biomass soil samples are taken and analyzed. The results obtained were used to predict the carbon storage. It was found that out of twenty tree samples Millingtonia hortensis which is commonly known as Cork tree possess maximum carbon storage (14.342kg/tree) and carbon sequestration (52.583kg/tree) respectively.

  2. Probing the Early Universe with the SZ Effect

    NASA Technical Reports Server (NTRS)

    Joy, M. K.; Carlstrom, J. E.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    The Cosmic Microwave Background Radiation (CMBR) which we observe today is relic radiation which last interacted with matter more than 10 billion years ago, when the expanding universe cooled to the point that free electrons and ionized nuclei recombined to form atoms. Prior to recombination, scattering between photons and free electrons was a very frequent occurrence, and the distance light could penetrate was small; afterwards, with free electrons out of circulation, the universe became largely transparent to light. Thus, the CMBR photons we observe today give us a clear view of the state of the early universe. Measured deviations in the intensity of the CMBR trace the small perturbations in the primordial matter density, which have been amplified by gravitational forces to form the magnificent, complex structures which comprise the present-day universe.

  3. Camera for Quasars in the Early Universe (CQUEAN)

    NASA Astrophysics Data System (ADS)

    Kim, Eunbin; Park, W.; Lim, J.; Jeong, H.; Kim, J.; Oh, H.; Pak, S.; Im, M.; Kuehne, J.

    2010-05-01

    The early universe of z ɳ is where the first stars, galaxies, and quasars formed, starting the re-ionization of the universe. The discovery and the study of quasars in the early universe allow us to witness the beginning of history of astronomical objects. In order to perform a medium-deep, medium-wide, imaging survey of quasars, we are developing an optical CCD camera, CQUEAN (Camera for QUasars in EArly uNiverse) which uses a 1024*1024 pixel deep-depletion CCD. It has an enhanced QE than conventional CCD at wavelength band around 1μm, thus it will be an efficient tool for observation of quasars at z > 7. It will be attached to the 2.1m telescope at McDonald Observatory, USA. A focal reducer is designed to secure a larger field of view at the cassegrain focus of 2.1m telescope. For long stable exposures, auto-guiding system will be implemented by using another CCD camera viewing an off-axis field. All these instruments will be controlled by the software written in python on linux platform. CQUEAN is expected to see the first light during summer in 2010.

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

    NASA Technical Reports Server (NTRS)

    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.

  5. Early Universe synthesis of asymmetric dark matter nuggets

    SciTech Connect

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

    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.

  6. Early Universe synthesis of asymmetric dark matter nuggets

    NASA Astrophysics Data System (ADS)

    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.

  7. Early Universe synthesis of asymmetric dark matter nuggets

    DOE PAGES

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

    2018-02-12

    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.

  8. Enhanced X-ray Emission from Early Universe Analog Galaxies

    NASA Astrophysics Data System (ADS)

    Brorby, Matthew; Kaaret, Philip; Prestwich, Andrea H.; Mirabel, I. Felix; Feng, Hua

    2016-04-01

    X-rays from binaries containing compact objects may have played an important role in heating the early Universe. Here we discuss our findings from X-ray studies of blue compact dwarf galaxies (BCDs), Lyman break analogs (LBAs), and Green Pea galaxies (GP), all of which are considered local analogs to high redshift galaxies. We find enhanced X-ray emission per unit star-formation rate which strongly correlates with decreasing metallicity. We find evidence for the existence of a L_X-SFR-Metallicity plane for star-forming galaxies. The exact properties of X-ray emission in the early Universe affects the timing and morphology of reionization, both being observable properties of current and future radio observations of the redshifted 21cm signal from neutral hydrogen.

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

    NASA Astrophysics Data System (ADS)

    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.

  10. The Transient High Energy Sky and Early Universe Surveyor

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    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.

  12. Probing Models of Dark Matter and the Early Universe

    NASA Astrophysics Data System (ADS)

    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

  13. X-ray Emission from Early Universe Analog Galaxies

    NASA Astrophysics Data System (ADS)

    Brorby, Matthew; Kaaret, Philip; Prestwich, Andrea H.; Mirabel, I. Felix; Feng, Hua

    2016-01-01

    Around 300,000 years after the Big Bang, the Universe had cooled enough to combine and form neutral atoms. This signified the beginning of a time known as the Dark Ages. Neutral matter began to fall into the dark matter gravitational wells that were seeded after the initial moments of the Big Bang. As the first stars and galaxies formed within these gravitational wells, the surrounding baryonic matter was heated and started to ionize. The source of energetic photons that heated and reionized the early Universe remains uncertain. Early galaxies had low metallicity and recent population synthesis calculations suggest that the number and luminosity of high-mass X-ray binaries are enhanced in star-forming galaxies with low metallicity, offering a potentially important and previously overlooked source of heating and reionization. Here we examine two types of local galaxies that have been shown to be good analogs to the early galaxies in the Universe: Blue compact dwarf galaxies (BCDs) and Lyman Break Analogs (LBAs).A BCD is defined by its blue optical colors, low metallicities, and physically small size. This makes BCDs the best available local analogs for early star formation. We analyzed data from a sample of 25 metal-poor BCDs and compared our results with those of near-solar metallicity galaxies. Using a Bayesian approach, we showed that the X-ray luminosity function for the low-metallicity BCDs is significantly elevated relative to the XLF for near-solar metallicity galaxies.Larger, gas-rich galaxies may have formed shortly after these first galaxies. These larger galaxies would be similar in their properties to the high-redshift Lyman break galaxies (LBGs). LBAs provide the best local comparison to the LBGs. We studied a sample of 10 LBAs in order to measure the relation between star formation rate and X-ray luminosity for these galaxies. We found that for LBAs with intermediate sub-solar metallicities, there is enhanced X-ray emission relative to the expected

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

    PubMed

    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. Phonological universals in early childhood: Evidence from sonority restrictions

    PubMed Central

    Berent, Iris; Harder, Katherine; Lennertz, Tracy

    2012-01-01

    Across languages, onsets with large sonority distances are preferred to those with smaller distances (e.g., bw>bd>lb; Greenberg, 1978). Optimality theory (Prince & Smolensky, 2004) attributes such facts to grammatical restrictions that are universally active in all grammars. To test this hypothesis, here, we examine whether children extend putatively universal sonority restrictions to onsets unattested in their language. Participants (M=4;04 years) were presented with pairs of auditory words—either identical (e.g., lbif→lbif) or epenthetically related (e.g., lbif→lebif)—and asked to judge their identity. Results showed that, like adults, children’s ability to detect epenthetic distortions was monotonically related to sonority distance (bw>bd>lb), and their performance was inexplicable by several statistical and phonetic factors. These findings suggest that sonority restrictions are active in early childhood and their scope is broad. PMID:22328807

  16. Hypermagnetic helicity evolution in early universe: leptogenesis and hypermagnetic diffusion

    SciTech Connect

    Semikoz, V.B.; Smirnov, A.Yu.; Sokoloff, D.D., E-mail: semikoz@yandex.ru, E-mail: smirnoff.alexandr@gmail.com, E-mail: sokoloff.dd@gmail.com

    2013-10-01

    We study hypermagnetic helicity and lepton asymmetry evolution in plasma of the early Universe before the electroweak phase transition (EWPT) accounting for chirality flip processes via inverse Higgs decays and sphaleron transitions which violate the left lepton number and wash out the baryon asymmetry of the Universe (BAU). In the scenario where the right electron asymmetry supports the BAU alone through the conservation law B/3−L{sub eR} = const at temperatures T > T{sub RL} ≅ 10 TeV the following universe cooling leads to the production of a non-zero left lepton (electrons and neutrinos) asymmetry. This is due to the Higgsmore » decays becoming more faster when entering the equilibrium at T = T{sub RL} with the universe expansion, Γ{sub RL} ∼ T > H ∼ T{sup 2}, resulting in the parallel evolution of both the right and the left electron asymmetries at T < T{sub RL} through the corresponding Abelian anomalies in SM in the presence of a seed hypermagnetic field. The hypermagnetic helicity evolution proceeds in a self-consistent way with the lepton asymmetry growth. The role of sphaleron transitions decreasing the left lepton number turns out to be negligible in given scenario. The hypermagnetic helicity can be a supply for the magnetic one in Higgs phase assuming a strong seed hypermagnetic field in symmetric phase.« less

  17. Viscous cosmology for early- and late-time universe

    NASA Astrophysics Data System (ADS)

    Brevik, Iver; Grøn, Øyvind; de Haro, Jaume; Odintsov, Sergei D.; Saridakis, Emmanuel N.

    From a hydrodynamicist’s point of view the inclusion of viscosity concepts in the macroscopic theory of the cosmic fluid would appear most natural, as an ideal fluid is after all an abstraction (exluding special cases such as superconductivity). Making use of modern observational results for the Hubble parameter plus standard Friedmann formalism, we may extrapolate the description of the universe back in time up to the inflationary era, or we may go to the opposite extreme and analyze the probable ultimate fate of the universe. In this review, we discuss a variety of topics in cosmology when it is enlarged in order to contain a bulk viscosity. Various forms of this viscosity, when expressed in terms of the fluid density or the Hubble parameter, are discussed. Furthermore, we consider homogeneous as well as inhomogeneous equations of state. We investigate viscous cosmology in the early universe, examining the viscosity effects on the various inflationary observables. Additionally, we study viscous cosmology in the late universe, containing current acceleration and the possible future singularities, and we investigate how one may even unify inflationary and late-time acceleration. Finally, we analyze the viscosity-induced crossing through the quintessence-phantom divide, we examine the realization of viscosity-driven cosmological bounces, and we briefly discuss how the Cardy-Verlinde formula is affected by viscosity.

  18. The Origin of Dust in the Early Universe

    NASA Technical Reports Server (NTRS)

    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.

  19. The Origin of Dust in the Early Universe

    NASA Technical Reports Server (NTRS)

    Dwek, Eliahu

    2010-01-01

    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.

  20. Fluctuation-driven electroweak phase transition. [in early universe

    NASA Technical Reports Server (NTRS)

    Gleiser, Marcelo; Kolb, Edward W.

    1992-01-01

    We examine the dynamics of the electroweak phase transition in the early Universe. For Higgs masses in the range 46 less than or = M sub H less than or = 150 GeV and top quark masses less than 200 GeV, regions of symmetric and asymmetric vacuum coexist to below the critical temperature, with thermal equilibrium between the two phases maintained by fluctuations of both phases. We propose that the transition to the asymmetric vacuum is completed by percolation of these subcritical fluctuations. Our results are relevant to scenarios of baryogenesis that invoke a weakly first-order phase transition at the electroweak scale.

  1. Resonant Production of Sterile Neutrinos in the Early Universe

    NASA Astrophysics Data System (ADS)

    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.

  2. Carbon Abundances in Starburst Galaxies of the Local Universe

    SciTech Connect

    Peña-Guerrero, María A.; Leitherer, Claus; Mink, Selma de

    The cosmological origin of carbon, the fourth most abundant element in the universe, is not well known and a matter of heavy debate. We investigate the behavior of C/O to O/H in order to constrain the production mechanism of carbon. We measured emission-line intensities in the spectral range from 1600 to 10000 Å on Space Telescope Imaging Spectrograph (STIS) long-slit spectra of 18 starburst galaxies in the local universe. We determined chemical abundances through traditional nebular analysis, and we used a Markov Chain Monte Carlo method to determine where our carbon and oxygen abundances lie in the parameter space. Wemore » conclude that our C and O abundance measurements are sensible. We analyzed the behavior of our sample in the [C/O] versus [O/H] diagram with respect to other objects such as DLAs, neutral ISM measurements, and disk and halo stars, finding that each type of object seems to be located in a specific region of the diagram. Our sample shows a steeper C/O versus O/H slope with respect to other samples, suggesting that massive stars contribute more to the production of C than N at higher metallicities, only for objects where massive stars are numerous; otherwise, intermediate-mass stars dominate the C and N production.« less

  3. Carbon Abundances in Starburst Galaxies of the Local Universe

    NASA Astrophysics Data System (ADS)

    Peña-Guerrero, María A.; Leitherer, Claus; de Mink, Selma; Wofford, Aida; Kewley, Lisa

    2017-10-01

    The cosmological origin of carbon, the fourth most abundant element in the universe, is not well known and a matter of heavy debate. We investigate the behavior of C/O to O/H in order to constrain the production mechanism of carbon. We measured emission-line intensities in the spectral range from 1600 to 10000 Å on Space Telescope Imaging Spectrograph (STIS) long-slit spectra of 18 starburst galaxies in the local universe. We determined chemical abundances through traditional nebular analysis, and we used a Markov Chain Monte Carlo method to determine where our carbon and oxygen abundances lie in the parameter space. We conclude that our C and O abundance measurements are sensible. We analyzed the behavior of our sample in the [C/O] versus [O/H] diagram with respect to other objects such as DLAs, neutral ISM measurements, and disk and halo stars, finding that each type of object seems to be located in a specific region of the diagram. Our sample shows a steeper C/O versus O/H slope with respect to other samples, suggesting that massive stars contribute more to the production of C than N at higher metallicities, only for objects where massive stars are numerous; otherwise, intermediate-mass stars dominate the C and N production.

  4. Stable carbon isotopes: possible clues to early life on Mars.

    PubMed

    Schidlowski, M

    1992-01-01

    Organic and inorganic carbon in terrestrial near-surface environments are characterized by a marked difference in their 13C/12C ratios which can be traced back in the Earth's sedimentary record over almost 4 billion years. There is no doubt that the bias in favour of 12C displayed by biogenic matter derives, for the most part, from the isotope-selecting properties of the carbon-fixing enzyme (ribulose-1,5-bisphosphate carboxylase) that is operative in the principal photosynthetic pathway and promotes most of the carbon transfer from the non-living to the living realm. Postulating a universality of biological principles in analogy to the proven universality of the laws of physics and chemistry, we may expect enzymatic reactions in exobiological systems to be beset with B similar kinetic fractionation effects. Hence, the retrieval from the oldest Martian sediments of isotopic fractionations between reduced and oxidized (carbonate) carbon may substantially constrain current conjectures on the possible existence of former life on Mars.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    DOE PAGES

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

    2018-04-06

    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 betweenmore » $$z\\simeq 6$$ 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 $$\\tau$$.« less

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

    SciTech Connect

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

    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 betweenmore » $$z\\simeq 6$$ 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 $$\\tau$$.« less

  8. The early cretaceous evolution of carbonate platforms from northern Oman

    SciTech Connect

    Masse, J.P.; Borgomano, J.; Maskiry, S.Al.

    1993-09-01

    In northern Oman (Jebel Akhdar and foothills) Hauterivian to early Aptian shallow carbonate platforms are widely extending and pass laterally to slope and basin environments in the Nakhl zone. Progradational geometries are identified in that zone where significant correlation between thickness and sediment types supports a prominent tectonic control. The platform records four main sedimentary breaks (drowning events). Early Barremian (lower Lekhwair Formation), Late Barremian (basal Kharaib Formation), lowermost early Aptian (upper Kharaib Formation) and middle Aptian (Shuaiba-Al Hassanat formations boundary). The late Aptian-early Albian hiatus (pre-Nahr Umr unconformity) is regarded as an early Albian tectonically driven erosion. In themore » Nakhl zone, coral-rudist limestones of late Aptian-early Albian (lower Al Hassanat Formation) document an east-west ribbon platform, the southward extension of which was obscured by the middle Albian erosions and rudist limestones of middle to late Albian (upper Al Hassanat Formation), a lateral equivalent of the Nahr Umr circa littoral shaly sediments, document an east-west-trending linear platform. The foregoing points out a northward progradation coeval with a southward transgressive major trend for the Hauterivian-early Aptian interval, a faulted margin corresponding with the Nakhl zone active during the Aptian-Albian, a late Aptian ribbon platform coeval with the Bab basin initiation southward, a regional uplifting and truncation during the early-Albian (Austrian phase), whereas shallow-water carbonates are still forming at the edge of the former platform, and an active linear platform at the northern edge of the Nahr Umr basin, the corresponding drowning contemporaneous with the onset of the Cenomanian platform eastward.« less

  9. Universal biology and the statistical mechanics of early life.

    PubMed

    Goldenfeld, Nigel; Biancalani, Tommaso; Jafarpour, Farshid

    2017-12-28

    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'. © 2017 The Author(s).

  10. Universal biology and the statistical mechanics of early life

    NASA Astrophysics Data System (ADS)

    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'.

  11. Follow the Carbon: Isotopic Labeling Studies of Early Earth Aerosol.

    PubMed

    Hicks, Raea K; Day, Douglas A; Jimenez, Jose L; Tolbert, Margaret A

    2016-11-01

    Despite the faint young Sun, early Earth might have been kept warm by an atmosphere containing the greenhouse gases CH 4 and CO 2 in mixing ratios higher than those found on Earth today. Laboratory and modeling studies suggest that an atmosphere containing these trace gases could lead to the formation of organic aerosol haze due to UV photochemistry. Chemical mechanisms proposed to explain haze formation rely on CH 4 as the source of carbon and treat CO 2 as a source of oxygen only, but this has not previously been verified experimentally. In the present work, we use isotopically labeled precursor gases and unit-mass resolution (UMR) and high-resolution (HR) aerosol mass spectrometry to examine the sources of carbon and oxygen to photochemical aerosol formed in a CH 4 /CO 2 /N 2 atmosphere. UMR results suggest that CH 4 contributes 70-100% of carbon in the aerosol, while HR results constrain the value from 94% to 100%. We also confirm that CO 2 contributes approximately 10% of the total mass to the aerosol as oxygen. These results have implications for the geochemical interpretations of inclusions found in Archean rocks on Earth and for the astrobiological potential of other planetary atmospheres. Key Words: Atmosphere-Early Earth-Planetary atmospheres-Carbon dioxide-Methane. Astrobiology 16, 822-830.

  12. Blast from the Past Gives Clues About Early Universe

    NASA Astrophysics Data System (ADS)

    2009-10-01

    Astronomers using the National Science Foundation's Very Large Array (VLA) radio telescope have gained tantalizing insights into the nature of the most distant object ever observed in the Universe -- a gigantic stellar explosion known as a Gamma Ray Burst (GRB). The explosion was detected on April 23 by NASA's Swift satellite, and scientists soon realized that it was more than 13 billion light-years from Earth. It represents an event that occurred 630 million years after the Big Bang, when the Universe was only four percent of its current age of 13.7 billion years. This explosion provides an unprecedented look at an era when the Universe was very young and also was undergoing drastic changes. The primal cosmic darkness was being pierced by the light of the first stars and the first galaxies were beginning to form. The star that exploded in this event was a member of one of these earliest generations of stars," said Dale Frail of the National Radio Astronomy Observatory. Astronomers turned telescopes from around the world to study the blast, dubbed GRB 090423. The VLA first looked for the object the day after the discovery, detected the first radio waves from the blast a week later, then recorded changes in the object until it faded from view more than two months later. "It's important to study these explosions with many kinds of telescopes. Our research team combined data from the VLA with data from X-ray and infrared telescopes to piece together some of the physical conditions of the blast," said Derek Fox of Pennsylvania State University. "The result is a unique look into the very early Universe that we couldn't have gotten any other way," he added. The scientists concluded that the explosion was more energetic than most GRBs, was a nearly-spherical blast, and that it expanded into a tenuous and relatively uniform gaseous medium surrounding the star. Astronomers suspect that the very first stars in the Universe were very different -- brighter, hotter, and more

  13. The early universe as a probe of new physics

    NASA Astrophysics Data System (ADS)

    Bird, Christopher Shane

    The Standard Model of Particle Physics has been verified to unprecedented precision in the last few decades. However there are still phenomena in nature which cannot be explained, and as such new theories will be required. Since terrestrial experiments are limited in both the energy and precision that can be probed, new methods are required to search for signs of physics beyond the Standard Model. In this dissertation, I demonstrate how these theories can be probed by searching for remnants of their effects in the early Universe. In particular I focus on three possible extensions of the Standard Model: the addition of massive neutral particles as dark matter, the addition of charged massive particles, and the existence of higher dimensions. For each new model, I review the existing experimental bounds and the potential for discovering new physics in the next generation of experiments. For dark matter, I introduce six simple models which I have developed, and which involve a minimum amount of new physics, as well as reviewing one existing model of dark matter. For each model I calculate the latest constraints from astrophysics experiments, nuclear recoil experiments, and collider experiments. I also provide motivations for studying sub-GeV mass dark matter, and propose the possibility of searching for light WIMPs in the decay of B-mesons and other heavy particles. For charged massive relics, I introduce and review the recently proposed model of catalyzed Big Bang nucleosynthesis. In particular I review the production of 6Li by this mechanism, and calculate the abundance of 7Li after destruction of 7Be by charged relics. The result is that for certain natural relics CBBN is capable of removing tensions between the predicted and observed 6Li and 7Li abundances which are present in the standard model of BBN. For extra dimensions, I review the constraints on the ADD model from both astrophysics and collider experiments. I then calculate the constraints on this model

  14. BOOK REVIEW: The Physics of the Early Universe

    NASA Astrophysics Data System (ADS)

    Scott, Douglas

    2007-11-01

    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

  15. Early atmospheric detection of carbon dioxide from carbon capture and storage sites.

    PubMed

    Pak, Nasrin Mostafavi; Rempillo, Ofelia; Norman, Ann-Lise; Layzell, David B

    2016-08-01

    The early atmospheric detection of carbon dioxide (CO2) leaks from carbon capture and storage (CCS) sites is important both to inform remediation efforts and to build and maintain public support for CCS in mitigating greenhouse gas emissions. A gas analysis system was developed to assess the origin of plumes of air enriched in CO2, as to whether CO2 is from a CCS site or from the oxidation of carbon compounds. The system measured CO2 and O2 concentrations for different plume samples relative to background air and calculated the gas differential concentration ratio (GDCR = -ΔO2/ΔCO2). The experimental results were in good agreement with theoretical calculations that placed GDCR values for a CO2 leak at 0.21, compared with GDCR values of 1-1.8 for the combustion of carbon compounds. Although some combustion plume samples deviated in GDCR from theoretical, the very low GDCR values associated with plumes from CO2 leaks provided confidence that this technology holds promise in providing a tool for the early detection of CO2 leaks from CCS sites. This work contributes to the development of a cost-effective technology for the early detection of leaks from sites where CO2 has been injected into the subsurface to enhance oil recovery or to permanently store the gas as a strategy for mitigating climate change. Such technology will be important in building public confidence regarding the safety and security of carbon capture and storage sites.

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

    PubMed

    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.

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

    PubMed

    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.

  18. Star Formation-Driven Winds in the Early Universe

    NASA Astrophysics Data System (ADS)

    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. Magnetic fields and chiral asymmetry in the early hot universe

    NASA Astrophysics Data System (ADS)

    Sydorenko, Maksym; Tomalak, Oleksandr; Shtanov, Yuri

    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.

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

    SciTech Connect

    Sydorenko, Maksym; Shtanov, Yuri; Tomalak, Oleksandr, E-mail: maxsydorenko@gmail.com, E-mail: tomalak@uni-mainz.de, E-mail: shtanov@bitp.kiev.ua

    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 andmore » 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.« less

  1. STELLAR 'FIREWORKS FINALE' CAME FIRST IN EARLY UNIVERSE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is an artist's impression of how the very early universe (less than 1 billion years old) might have looked when it went through a voracious onset of star formation, converting primordial hydrogen into myriad stars at an unprecedented rate. Back then the sky would have looked markedly different from the sea of quiescent galaxies around us today. The sky is ablaze with primeval starburst galaxies; giant elliptical and spiral galaxies have yet to form. Within the starburst galaxies, bright knots of hot blue stars come and go like bursting fireworks shells. Regions of new starbirth glow intensely red under a torrent of ultraviolet radiation. The most massive stars self-detonate as supernovas, which explode across the sky like a string of firecrackers. A foreground starburst galaxy at lower right is sculpted with hot bubbles from supernova explosions and torrential stellar winds. Unlike today there is very little dust in these galaxies, because the heavier elements have not yet been cooked up through nucleosynthesis in stars. Recent analysis of Hubble Space Telescope deep sky images supports the theory that the first stars in the universe appeared in an abrupt eruption of star formation, rather than at a gradual pace. Painting Credit: Adolf Schaller for STScI

  2. Carbon isotope fractionation of sapropelic organic matter during early diagenesis

    USGS Publications Warehouse

    Spiker, E. C.; Hatcher, P.G.

    1984-01-01

    Study of an algal, sapropelic sediment from Mangrove Lake, Bermuda shows that the mass balance of carbon and stable carbon isotopes in the major organic constituents is accounted for by a relatively straightforward model of selective preservation during diagenesis. The loss of 13C-enriched carbohydrates is the principal factor controlling the intermolecular mass balance of 13C in the sapropel. Results indicate that labile components are decomposed leaving as a residual concentrate in the sediment an insoluble humic substance that may be an original biochemical component of algae and associated bacteria. An overall decrease of up to about 4??? in the ?? 13C values of the organic matter is observed as a result of early diagenesis. ?? 1984.

  3. Constraints on Early Triassic carbon cycle dynamics from paired organic and inorganic carbon isotope records

    NASA Astrophysics Data System (ADS)

    Meyer, K. M.; Yu, M.; Lehrmann, D.; van de Schootbrugge, B.; Payne, J. L.

    2013-01-01

    Large δ13C excursions, anomalous carbonate precipitates, low diversity assemblages of small fossils, and evidence for marine euxinia in uppermost Permian and Lower Triassic strata bear more similarity to Neoproterozoic carbonates than to the remainders of the Permian and Triassic systems. Middle Triassic diversification of marine ecosystems coincided with the waning of anoxia and stabilization of the global carbon cycle, suggesting that environment-ecosystem linkages were important to biological recovery. However, the Earth system behavior responsible for these large δ13C excursions remains poorly constrained. Here we present a continuous Early Triassic δ13Corg record from south China and use it to test the extent to which Early Triassic excursions in δ13Ccarb record changes in the δ13C of marine dissolved inorganic carbon (DIC). Regression analysis demonstrates a significant positive correlation between δ13Corg and δ13Ccarb across multiple sections that span a paleoenvironmental gradient. Such a correlation is incompatible with diagenetic alteration because no likely mechanism will alter both δ13Corg and δ13Ccarb records in parallel and therefore strongly indicates a primary depositional origin. A simple explanation for this correlation is that a substantial portion of the preserved Corg was derived from the contemporaneous DIC pool, implying that the observed excursions reflect variation in the δ13C of the exogenic carbon reservoir (ocean, atmosphere, biomass). These findings support existing evidence that large δ13C excursions are primary and therefore strengthen the case that large-scale changes to the carbon cycle were mechanistically linked to the low diversity and small size of Early Triassic fossils. Associated sedimentary and biogeochemical phenomena further suggest that similar associations in Neoproterozoic and Cambrian strata may reflect the same underlying controls.

  4. A Glimpse of the Very Early Universal Web

    NASA Astrophysics Data System (ADS)

    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

  5. Nearby star cluster yields insights into early universe

    NASA Astrophysics Data System (ADS)

    1998-07-01

    The nebula offers a unique opportunity for a close-up glimpse of the "firestorm" accompanying the birth of extremely massive stars, each blazing with the brilliance of 300,000 of our suns. Such galactic fireworks were much more common billions of years ago in the early universe, when most star formation took place. "This is giving us new insights into the physical mechanisms governing star formation in far away galaxies that existed long ago," says Mohammad Heydari-Malayeri (Paris Observatory, France), who headed the international team of astronomers who made the discovery using Hubble's Wide Field and Planetary Camera 2. Because these stars are deficient in heavier elements, they also evolve much like the universe's earliest stars, which were made almost exclusively of the primordial elements hydrogen and helium that were created in the big bang. The Small Magellanic Cloud is a unique laboratory for studying star formation in the early universe since it is the closest and best seen galaxy containing so-called "metal-poor" first- and second -generation type stars. These observations show that massive stars may form in groups. "As a result, it is more likely some of these stars are members of double and multiple star systems," says Heydari-Malayeri. "The multiple systems will affect stellar evolution considerably by ejecting a great deal of matter into space." This furious rate of mass loss from these stars is evident in the Hubble picture, which reveals dramatic shapes sculpted in the nebula's wall of glowing gases by violent stellar winds and shock waves. "This implies a very turbulent environment typical of young star formation regions," Heydari-Malayeri adds. He believes one of the members of the cluster may be an extremely rare and short-lived class of super-hot star (50,000 degrees Kelvin) called a Wolf-Rayet. This star represents a violent, transitional phase in the final years of a massive star's existence - before it ultimately explodes as a supernova. "If

  6. A universal model for nanoporous carbon supercapacitors applicable to diverse pore regimes, carbon materials, and electrolytes.

    PubMed

    Huang, Jingsong; Sumpter, Bobby G; Meunier, Vincent

    2008-01-01

    Supercapacitors, commonly called electric double-layer capacitors (EDLCs), are emerging as a novel type of energy-storage device with the potential to substitute batteries in applications that require high power densities. In response to the latest experimental breakthrough in nanoporous carbon supercapacitors, we propose a heuristic theoretical model that takes pore curvature into account as a replacement for the EDLC model, which is based on a traditional parallel-plate capacitor. When the pore size is in the mesopore regime (2-50 nm), counterions enter mesoporous carbon materials and approach the pore wall to form an electric double-cylinder capacitor (EDCC); in the micropore regime (<2 nm), solvated/desolvated counterions line up along the pore axis to form an electric wire-in-cylinder capacitor (EWCC). In the macropore regime (>50 nm) at which pores are large enough so that pore curvature is no longer significant, the EDCC model can be reduced naturally to the EDLC model. We present density functional theory calculations and detailed analyses of available experimental data in various pore regimes, which show the significant effects of pore curvature on the supercapacitor properties of nanoporous carbon materials. It is shown that the EDCC/EWCC model is universal for carbon supercapacitors with diverse carbon materials, including activated carbon materials, template carbon materials, and novel carbide-derived carbon materials, and with diverse electrolytes, including organic electrolytes, such as tetraethylammonium tetrafluoroborate (TEABF(4)) and tetraethylammonium methylsulfonate (TEAMS) in acetonitrile, aqueous H(2)SO(4) and KOH electrolytes, and even an ionic liquid electrolyte, such as 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMI-TFSI). The EDCC/EWCC model allows the supercapacitor properties to be correlated with pore size, specific surface area, Debye length, electrolyte concentration and dielectric constant, and solute ion size It

  7. Environmental change during the Late Berriasian - Early Valanginian: a prelude to the late Early Valanginian carbon-isotope event?

    NASA Astrophysics Data System (ADS)

    Morales, Chloé; Schnyder, Johann; Spangenberg, Jorge; Adatte, Thierry; Westermann, Stephane; Föllmi, Karl

    2010-05-01

    -746. F^llmi, K.B., Bodin, S., Godet, A., Linder, P. and Van de Schootbrugge, B. (2007). "Unlocking paleo-environmental information from Early Cretaceous shelf sediments in the Helvetic Alps: stratigraphy is the key!" Swiss j. geosci. 100: 349-369. Gr^cke, D.R., Price, G.D., Robinson, S.A., Baraboshkin, E.Y., Mutterlose, J. and Ruffell, A.H. (2005). "The Upper Valanginian (Early Cretaceous) positive carbon-isotope event recorded in terrestrial plants." Earth and Planetary Science Letters 240(2): 495-509. Hallam, A., Grose, J.A. and Ruffell, A.H. (1991). "Palaeoclimatic significance of changes in clay mineralogy across the Jurassic-Cretaceous boundary in England and France." Palaeogeography, Palaeoclimatology, Palaeoecology 81(3-4): 173-187. Hennig, S. (2003). Geochemical and sedimentological evidence for environmental changes in the Valanginian (Early Cretaceous) of the Tethys region, ETH Zurich: 189. Ogg, J.G., Ogg, G., Gradstein, F.M., 2008. The concise geological time scale. Cambridge University Press. 177 pp. Reboulet, S., Mattioli, E., Pittet, B., Baudin, F., Olivero, D. and Proux, O. (2003). "Ammonoid and nannoplankton abundance in Valanginian (early Cretaceous) limestone-marl successions from the southeast France Basin: carbonate dilution or productivity?" Palaeogeography, Palaeoclimatology, Palaeoecology 201(1-2): 113-139. Schnyder, J., Baudin, F. and Deconinck, J.-F. (2009). "Occurrence of organic-matter-rich beds in Early Cretaceous coastal evaporitic setting (Dorset, UK): a link to long-term palaeoclimate changes?" Cretaceous Research 30: 356-366. Van de Schootbrugge, B., Kuhn, O., Adatte, T., Steinmann, P. and F^llmi, K. (2003). "Decoupling of P- and Corg-burial following Early Cretaceous (Valanginian-Hauterivian) platform drowning along the NW Tethyan margin." Palaeogeography, Palaeoclimatology, Palaeoecology 199(3-4): 315-331. Westermann, S., F^llmi, K.B., Adatte, T., Matera, V., Schnyder, J., Fleitmann, D., Fiet, N., Ploch, I. and Duchamp-Alphonse, S. "The

  8. PhD Thesis: String theory in the early universe

    NASA Astrophysics Data System (ADS)

    Gwyn, Rhiannon

    2009-11-01

    The intersection of string theory with cosmology is unavoidable in the early universe, and its exploration may shine light on both fields. In this thesis, three papers at this intersection are presented and reviewed, with the aim of providing a thorough and pedagogical guide to their results. First, we address the longstanding problem of finding a string theory realisation of the axion. Using warped compactifications in heterotic string theory, we show that the axion decay constant can be lowered to acceptable values by the warp factor. Next, we move to the subject of cosmic strings, whose network evolution could have important consequences for astrophysics and cosmology. In particular, there are quantitative differences between cosmic superstring networks and GUT cosmic string networks. We investigate the properties of cosmic superstring networks in warped backgrounds, giving the tension and properties of three-string junctions in these backgrounds. Finally, we examine the possibility that cosmic strings in heterotic string theory could be responsible for generating the galactic magnetic fields that seeded those observed today.

  9. Early universe cosmology, effective supergravity, and invariants of algebraic forms

    NASA Astrophysics Data System (ADS)

    Sinha, Kuver

    2015-09-01

    The presence of light scalars can have profound effects on early universe cosmology, influencing its thermal history as well as paradigms like inflation and baryogenesis. Effective supergravity provides a framework to make quantifiable, model-independent studies of these effects. The Riemannian curvature of the Kähler manifold spanned by scalars belonging to chiral superfields, evaluated along supersymmetry breaking directions, provides an order parameter (in the sense that it must necessarily take certain values) for phenomena as diverse as slow roll modular inflation, nonthermal cosmological histories, and the viability of Affleck-Dine baryogenesis. Within certain classes of UV completions, the order parameter for theories with n scalar moduli is conjectured to be related to invariants of n -ary cubic forms (for example, for models with three moduli, the order parameter is given by a function on the ring of invariants spanned by the Aronhold invariants). Within these completions, and under the caveats spelled out, this may provide an avenue to obtain necessary conditions for the above phenomena that are in principle calculable given nothing but the intersection numbers of a Calabi-Yau compactification geometry. As an additional result, abstract relations between holomorphic sectional and bisectional curvatures are utilized to constrain Affleck-Dine baryogenesis on a wide class of Kähler geometries.

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

    PubMed

    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.

  11. Isotropy of the early universe from CMB anisotropies

    SciTech Connect

    Donoghue, Evan P.; University of Notre Dame, Notre Dame, Indiana 46556; Donoghue, John F.

    The acoustic peak in the cosmic microwave background power spectrum is sensitive to causal processes and cosmological parameters in the early universe up to the time of last scattering. We provide limits on correlated spatial variations of the peak height and peak position and interpret these as constraints on the spatial variation of the cosmological parameters (baryon density, cold dark matter density, and cosmological constant as well as the amplitude and tilt of the original fluctuations). We utilize recent work of Hansen, Banday, and Gorski who have studied the spatial isotropy of the power spectrum as measured by WMAP bymore » performing the power spectrum analysis on smaller patches of the sky. We find that there is no statistically significant correlated asymmetry of the peak. Hansen, Banday, and Gorski have also provided preliminary indications of a preferred direction in the lower angular momentum range (l{approx}2-40) and we show how possible explanations of this asymmetry are severely constrained by the data on the acoustic peak. Finally we show a possible non-Gaussian feature in the data, associated with a difference in the northern and southern galactic hemispheres.« less

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Early atmospheric detection of carbon dioxide from carbon capture and storage sites

    PubMed Central

    Pak, Nasrin Mostafavi; Rempillo, Ofelia; Norman, Ann-Lise; Layzell, David B.

    2016-01-01

    ABSTRACT The early atmospheric detection of carbon dioxide (CO2) leaks from carbon capture and storage (CCS) sites is important both to inform remediation efforts and to build and maintain public support for CCS in mitigating greenhouse gas emissions. A gas analysis system was developed to assess the origin of plumes of air enriched in CO2, as to whether CO2 is from a CCS site or from the oxidation of carbon compounds. The system measured CO2 and O2 concentrations for different plume samples relative to background air and calculated the gas differential concentration ratio (GDCR = −ΔO2/ΔCO2). The experimental results were in good agreement with theoretical calculations that placed GDCR values for a CO2 leak at 0.21, compared with GDCR values of 1–1.8 for the combustion of carbon compounds. Although some combustion plume samples deviated in GDCR from theoretical, the very low GDCR values associated with plumes from CO2 leaks provided confidence that this technology holds promise in providing a tool for the early detection of CO2 leaks from CCS sites.  Implications: This work contributes to the development of a cost-effective technology for the early detection of leaks from sites where CO2 has been injected into the subsurface to enhance oil recovery or to permanently store the gas as a strategy for mitigating climate change. Such technology will be important in building public confidence regarding the safety and security of carbon capture and storage sites. PMID:27111469

  14. Topological Defects and Structures in the Early Universe

    NASA Astrophysics Data System (ADS)

    Zhu, Yong

    1997-08-01

    This thesis discusses the topological defects generated in the early universe and their contributions to cosmic structure formation. First, we investigate non-Gaussian isocurvature perturbations generated by the evolution of Goldstone modes during inflation. If a global symmetry is broken before inflation, the resulting Goldstone modes are disordered during inflation in a precise and predictable way. After inflation these Goldstone modes order themselves in a self-similar way, much as Goldstone modes in field ordering scenarios based on the Kibble mechanism. For (Hi2/Mpl2)~10- 6, through their gravitational interaction these Goldstone modes generate density perturbations of approximately the right magnitude to explain the cosmic microwave background (CMB) anisotropy and seed the structure seen in the universe today. In such a model non-Gaussian perturbations result because to lowest order density perturbations are sourced by products of Gaussian fields. We explore the issue of phase dispersion and conclude that this non-Gaussian model predicts Doppler peaks in the CMB anisotropy. Topological defects generated from quantum fluctuations during inflation are studied in chapter four. We present a calculation of the power spectrum generated in a classically symmetry-breaking O(N) scalar field through inflationary quantum fluctuations, using the large-N limit. The effective potential of the theory in de Sitter space is obtained from a gap equation which is exact at large N. Quantum fluctuations restore the O(N) symmetry in de Sitter space, but for the finite values of N of interest, there is symmetry breaking and phase ordering after inflation, described by the classical nonlinear sigma model. The scalar field power spectrum is obtained as a function of the scalar field self-coupling. In the second part of the thesis, we investigate non-Abelian topological worm-holes, obtained when winding number one texture field is coupled to Einstein gravity with a conserved global

  15. NEARBY MASSIVE STAR CLUSTER YIELDS INSIGHTS INTO EARLY UNIVERSE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A NASA Hubble Space Telescope 'family portrait' of young, ultra-bright stars nested in their embryonic cloud of glowing gases. The celestial maternity ward, called N81, is located 200,000 light-years away in the Small Magellanic Cloud (SMC), a small irregular satellite galaxy of our Milky Way. Hubble's exquisite resolution allows astronomers to pinpoint 50 separate stars tightly packed in the nebula's core within a 10 light-year diameter - slightly more than twice the distance between earth and the nearest star to our sun. The closest pair of stars is only 1/3 of a light-year apart (0.3 arcseconds in the sky). This furious rate of mass loss from these super-hot stars is evident in the Hubble picture that reveals dramatic shapes sculpted in the nebula's wall of glowing gases by violent stellar winds and shock waves. A pair of bright stars in the center of the nebula is pouring out most of the ultraviolet radiation to make the nebula glow. Just above them, a small dark knot is all that's left of the cold cloud of molecular hydrogen and dust the stars were born from. Dark absorption lanes of residual dust trisect the nebula. The nebula offers a unique opportunity for a close-up glimpse at the 'firestorm' accompanying the birth of extremely massive stars, each blazing with the brilliance of 300,000 of our suns. Such galactic fireworks were much more common billions of years ago in the early universe, when most star formation took place. The 'natural-color' view was assembled from separate images taken with the Wide Field and Planetary Camera 2, in ultraviolet light and two narrow emission lines of ionized Hydrogen (H-alpha, H-beta). The picture was taken on September 4, 1997. Credit: Mohammad Heydari-Malayeri (Paris Observatory, France), NASA/ESA

  16. Teaching Early Childhood Assessment Online: A State-Wide Multi-University Collaboration

    ERIC Educational Resources Information Center

    Murray, Ann D.; McDonald, Angie; York, Marti A.

    2006-01-01

    This paper describes an online early childhood assessment course that was developed through a multi-university collaboration with support from a state improvement grant. Collaborators from three universities developed the course to address a new early childhood unified license (birth to age 8, regular and special education) in the state of Kansas.…

  17. Carbon isotopic evidence for photosynthesis in Early Cambrian oceans

    NASA Astrophysics Data System (ADS)

    Surge, Donna M.; Savarese, Michael; Dodd, J. Robert; Lohmann, Kyger C.

    1997-06-01

    Were the first metazoan reefs ecologically similar to modern tropical reefs, enabling them to persist under oligotrophic conditions? We tested the hypothesis of ecological similarity by employing a geochemical approach. Petrography, cathodoluminescence, trace elements, and stable isotope analyses of primary precipitates of the Lower Cambrian Ajax Limestone, South Australia, indicate preservation of original C isotopic composition. All primary carbonate components exhibit C isotopic values similar to the composition of inorganically precipitated fibrous marine cements, suggesting that archaeocyaths and the calcimicrobe Epiphyton precipitated skeletal carbonate in equilibrium with ambient seawater in the absence of vital effects. Such data do not support the contention that archaeocyaths possessed photosymbionts. However, a +0.55‰ shift in δ13C occurs in reefs developed under shallower-water conditions relative to deeper reefs. This shift suggests the stratification of primary production in Early Cambrian oceans. The pattern is similar to that seen in the modern ocean, whereby significant photosynthesis modulates the C isotopic composition of the photic zone.

  18. Influence of carbon dioxide clouds on early martian climate.

    PubMed

    Mischna, M A; Kasting, J F; Pavlov, A; Freedman, R

    2000-06-01

    Recent studies have shown that clouds made of carbon dioxide ice may have warmed the surface of early Mars by reflecting not only incoming solar radiation but upwelling IR radiation as well. However, these studies have not treated scattering self-consistently in the thermal IR. Our own calculations, which treat IR scattering properly, confirm these earlier calculations but show that CO2 clouds can also cool the surface, especially if they are low and optically thick. Estimating the actual effect of CO2 clouds on early martian climate will require three-dimensional models in which cloud location, height, and optical depth, as well as surface temperature and pressure, are determined self-consistently. Our calculations further confirm that CO2 clouds should extend the outer boundary of the habitable zone around a star but that there is still a finite limit beyond which above-freezing surface temperatures cannot be maintained by a CO2-H2O atmosphere. For our own Solar System, the absolute outer edge of the habitable zone is at approximately 2.4 AU.

  19. Universal Prekindergarten and Early Childhood Education Act of 2009

    THOMAS, 111th Congress

    Rep. Norton, Eleanor Holmes [D-DC-At Large

    2009-10-08

    House - 11/16/2009 Referred to the Subcommittee on Early Childhood, Elementary, and Secondary Education. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  20. Universal Prekindergarten and Early Childhood Education Act of 2013

    THOMAS, 113th Congress

    Rep. Norton, Eleanor Holmes [D-DC-At Large

    2013-02-27

    House - 04/23/2013 Referred to the Subcommittee on Early Childhood, Elementary, and Secondary Education. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  1. Universal Prekindergarten and Early Childhood Education Act of 2011

    THOMAS, 112th Congress

    Rep. Norton, Eleanor Holmes [D-DC-At Large

    2011-11-17

    House - 03/29/2012 Referred to the Subcommittee on Early Childhood, Elementary, and Secondary Education. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  2. Insights into the Processing of Carbon by Early Microbial Ecosystems

    NASA Technical Reports Server (NTRS)

    DesMarais, D.; Bebout, B.; Carpenter, S.; Discipulo, S.; Londry, K.; Habicht, K.; Turk, K.

    2003-01-01

    Interactions between Earth and the biosphere that were crucial for early biological evolution also influenced substantially the processes that circulate C between its reservoirs in the atmosphere, ocean, crust and mantle. The C-13 C-12 values of crustal carbonates and organics have recorded changes both in biological discrimination and in the relative rates of burial of organics and carbonates. A full interpretation of these patterns needs further isotopic studies of microbial ecosystems and individual anaerobes. Thus we measured carbon isotope discrimination during autotrophic and heterotrophic growth of pure cultures of sulfate-reducing bacteria and archaea (SRB and SRA). Discrimination during CO2 assimilation is significantly larger than during heterotrophic growth on lactate or acetate. SRB grown lithoautotrophically consumed less than 3% of available CO2 and exhibited substantial discrimination, as follows: Desulfobacterium autotrophicum (alpha 1.0100 to 1.0123), Desulfobacter hydrogenophilus (alpha = 0.0138), and Desulfotomuculum acetoxidans (alpha = 1.0310). Mixotrophic growth of Desulfovibrio desulfuricans on acetate and CO2 resulted in biomass with delta C-13 composition intermediate to that of the substrates. We have recently extended these experiments to include the thermophilic SRA Archeoglobus spp. Ecological forces also influence isotopic discrimination. Accordingly, we quantified the flow of C and other constituents in modern marine cyanobacterial mats, whose ancestry extends back billions of years. Such ecosystem processes shaped the biosignatures that entered sediments and atmospheres. At Guerrero Negro, BCS, Mexico, we examined mats dominated by Microcoleus (subtidal) and Lyngbya (intertidal to supratidal) cyanobacteria. During 24 hour cycles, we observed the exchange of O2 and dissolved inorganic C (DIC) between mats and the overlying water. Microcoleus mats assimilated near-equal amounts of DIC during the day as they released at night, but

  3. Investigating the Early Carbon Cycle Using Carbonaceous Inclusions and Dissolved Carbon in Detrital Zircon

    NASA Astrophysics Data System (ADS)

    Bell, E. A.; Boehnke, P.; Harrison, M.; Mao, W. L.

    2015-12-01

    Because the terrestrial rock record extends only to ~4 Ga and older materials thus far identified are limited to detrital zircons, information about volatile abundances and cycles on early Earth is limited. Carbon, for instance, plays an important role not only in the modern biosphere but also in deep recycling of materials between the crust and mantle. We are investigating the record of carbon abundance and origin in Hadean zircons from Jack Hills (W. Australia) using two main approaches. First, carbon may partition into the zircon structure at trace levels during crystallization from a magma, and better understanding of this partitioning behavior will allow for zircon's use as a monitor of magmatic carbon contents. We have measured carbon abundances in zircon from a variety of igneous rocks (gabbro; I-, A-, and S-type granitoids) via SIMS and found that although abundances are typically low (average raw 12C/30Si ~ 1x10-6), S-type granite zircons can reach a factor of 1000 over this background. Around 10% of Hadean zircons investigated show similar enrichments, consistent with other evidence for the derivation of many Jack Hills zircons from S-type granitoids and with the establishment of modern-level carbon abundances in the crust by ca. 4.2 Ga. Diamond and graphite inclusions reported in the Jack Hills zircons by previous studies proved to be contamination by polishing debris, leaving the true abundance of these materials in the population uncertain. On a second front, we have identified and investigated primary carbonaceous inclusions in these zircons. From a population of over 10,000 Jack Hills zircons, we identified one concordant 4.10±0.01 Ga zircon that contains primary graphite inclusions (so interpreted due to their enclosure in a crack-free zircon host as shown by transmission X-ray microscopy and their crystal habit). Their δ13CPDB of -24±5‰ is consistent with a biogenic origin and, in the absence of a likely inorganic mechanism to produce such a

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

    ERIC Educational Resources Information Center

    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. Early Literacy Teacher Preparation: One University's Perspective

    ERIC Educational Resources Information Center

    Berenato, Carolyn; Severino, Lori

    2017-01-01

    Colleges and universities can have an impact on the entire field of education when preparing teachers for one of the most challenging part of the job: teaching literacy. When teachers are properly trained and have a toolbox of strategies and teaching techniques to use, they can have a tremendous impact on student learning. In teacher preparation…

  6. The Early Universe and High-Energy Physics.

    ERIC Educational Resources Information Center

    Schramm, David N.

    1983-01-01

    Many properties of new particle field theories can only be tested by comparing their predictions about the physical conditions immediately after the big bang with what can be reconstructed about this event from astronomical data. Facts/questions about big bang, unified field theories, and universe epochs/mass are among the topics discussed. (JN)

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

    PubMed Central

    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.

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

    NASA Astrophysics Data System (ADS)

    Amati, L.

    2016-10-01

    THESEUS is a mission concept by a large international collaboration aimed at exploiting GRBs for investigating the early universe and at vastly increasing the discovery space of the high energy transient phenomena over the entire cosmic history.

  9. Nuclear and particle physics in the early universe

    NASA Technical Reports Server (NTRS)

    Schramm, D. N.

    1981-01-01

    Basic principles and implications of Big Bang cosmology are reviewed, noting the physical evidence of a previous universe temperature of 10,000 K and theoretical arguments such as grand unification decoupling indicating a primal temperature of 10 to the 15th eV. The Planck time of 10 to the -43rd sec after the Big Bang is set as the limit before which gravity was quantized and nothing is known. Gauge theories of elementary particle physics are reviewed for successful predictions of similarity in weak and electromagnetic interactions and quantum chromodynamic predictions for strong interactions. The large number of photons in the universe relative to the baryons is considered and the grand unified theories are cited as showing the existence of baryon nonconservation as an explanation. Further attention is given to quark-hadron phase transition, the decoupling for the weak interaction and relic neutrinos, and Big Bang nucleosynthesis.

  10. Accretion and differentiation of carbon in the early Earth.

    PubMed

    Tingle, T N

    1998-05-15

    The abundance of C in carbonaceous and ordinary chondrites decreases exponentially with increasing shock pressure as inferred from the petrologic shock classification of Scott et al. [Scott, E.R.D., Keil, K., Stoffler, D., 1992. Shock metamorphism of carbonaceous chondrites. Geochim. Cosmochim. Acta 56, 4281-4293] and Stoffler et al. [Stoffler, D., Keil, K., Scott, E.R.D., 1991. Shock metamorphism of ordinary chondrites. Geochim. Cosmochim. Acta 55, 3845-3867]. This confirms the experimental results of Tyburczy et al. [Tyburczy, J.A., Frisch, B., Ahrens, T.J., 1986. Shock-induced volatile loss from a carbonaceous chondrite: implications for planetary accretion. Earth Planet. Sci. Lett. 80, 201-207] on shock-induced devolatization of the Murchison meteorite showing that carbonaceous chondrites appear to be completely devolatilized at impact velocities greater than 2 km s-1. Both of these results suggest that C incorporation would have been most efficient in the early stages of accretion, and that the primordial C content of the Earth was between 10(24) and 10(25) g C (1-10% efficiency of incorporation). This estimate agrees well with the value of 3-7 x 10(24) g C based on the atmospheric abundance of 36Ar and the chondritic C/36Ar (Marty and Jambon, 1987). Several observations suggest that C likely was incorporated into the Earth's core during accretion. (1) Graphite and carbides are commonly present in iron meteorites, and those iron meteorites with Widmanstatten patterns reflecting the slowest cooling rates (mostly Group I and IIIb) contain the highest C abundances. The C abundance-cooling rate correlation is consistent with dissolution of C into Fe-Ni liquids that segregated to form the cores of the iron meteorite parent bodies. (2) The carbon isotopic composition of graphite in iron meteorites exhibits a uniform value of -5% [Deines, P., Wickman, F.E. 1973. The isotopic composition of 'graphitic' carbon from iron meteorites and some remarks on the troilitic

  11. Developing Peer Mentoring Support for TAFE Students Entering 1st-Year University Early Childhood Studies

    ERIC Educational Resources Information Center

    Heirdsfield, Ann; Walker, Sue; Walsh, Kerryann

    2005-01-01

    At Queensland University of Technology (QUT, Australia), in the Bachelor of Education (BEd) (Early Childhood) (EC), Technical and Further Education (TAFE) students with a diploma enroll with advanced standing (1 year's credit). These students share many challenges faced by 1st-year university students--workload, technology, academic orientation,…

  12. Addressing the University's Tripartite Mission through an Early Childhood Movement Program.

    ERIC Educational Resources Information Center

    Marston, Rip

    2002-01-01

    Describes the University of Northern Iowa's early childhood motor laboratory, which brings together college students, preschoolers, and parents while contributing to each strand of the university's three-strand mission of teaching, scholarly endeavors, and service. The article describes program sessions, highlights the tripartite mission, and…

  13. University Students' Early Maladaptive Schemas' Prediction of Their Mindfulness Levels

    ERIC Educational Resources Information Center

    Yalcin, S.Barbaros; Kavakli, Mehmet; Kesici, Sahin; Ak, Mehmet

    2017-01-01

    Purpose: The aim of this study is to determine whether university students' early maladaptive schemas predict their mindfulness levels or not. Methods: The study was carried out in the relational screening model. The study group consisted of 293 university students; 237 (80,9%) females and 56 (19,1%) males. "Mindful Attention Awareness Scale…

  14. A Pathway to Enhancing Professionalism: Building a Bridge between TAFE and University Early Childhood Qualifications

    ERIC Educational Resources Information Center

    Whitington, Victoria; Ebbeck, Marjory; Diamond, Alexandra; Yim, Hoi Yin Bonnie

    2009-01-01

    It has been argued that a key strategy to improve developmental and educational outcomes for young children is to increase the number of childcare staff with early childhood university degrees (Saracho & Spodek, 2007). In order to upgrade the qualifications of staff, a number of Australian universities provide pathways that enable graduates of…

  15. Strategic Programming for Early University Entrants: Creating Support for Socio-Emotional Needs

    ERIC Educational Resources Information Center

    Lancour, Julie A.

    2011-01-01

    This article introduces "Resiliency Training," a program designed to support early university entrants as they take on the challenges and adventures of their sophomore and junior year at the University of Washington (UW). As the Academic Counselor and Counseling Services Coordinator for the Robinson Center, watching the students engage…

  16. A Balancing Act: Facilitating a University Education Induction Programme for (Early Career) Academics

    ERIC Educational Resources Information Center

    Reddy, Sarasvathie; Searle, Ruth L.; Shawa, Lester B.; Teferra, Damtew

    2016-01-01

    This article examines the University Education Induction Programme (UEIP), an academic development programme, delivered at the University of KwaZulu-Natal, South Africa. The authors, who developed and now facilitate the UEIP, deliver the programme to early career academics and senior academics as per a senate-mandated requirement. Drawing on…

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  19. A Case Study of the Development of an Early Retirement Program for University Faculty.

    ERIC Educational Resources Information Center

    Chronister, Jay L.; Trainer, Aileen

    1985-01-01

    To offset declining enrollments, financial constraints, younger faculties, and high tenure ratios, some institutions are considering early retirement programs to facilitate faculty turnover. A University of Virginia faculty committee reviewed several early retirement options and selected a cost-effective bridging program with ample incentives and…

  20. Dusty starburst galaxies in the early Universe as revealed by gravitational lensing.

    PubMed

    Vieira, J D; Marrone, D P; Chapman, S C; De Breuck, C; Hezaveh, Y D; Weiβ, A; Aguirre, J E; Aird, K A; Aravena, M; Ashby, M L N; Bayliss, M; Benson, B A; Biggs, A D; Bleem, L E; Bock, J J; Bothwell, M; Bradford, C M; Brodwin, M; Carlstrom, J E; Chang, C L; Crawford, T M; Crites, A T; de Haan, T; Dobbs, M A; Fomalont, E B; Fassnacht, C D; George, E M; Gladders, M D; Gonzalez, A H; Greve, T R; Gullberg, B; Halverson, N W; High, F W; Holder, G P; Holzapfel, W L; Hoover, S; Hrubes, J D; Hunter, T R; Keisler, R; Lee, A T; Leitch, E M; Lueker, M; Luong-Van, D; Malkan, M; McIntyre, V; McMahon, J J; Mehl, J; Menten, K M; Meyer, S S; Mocanu, L M; Murphy, E J; Natoli, T; Padin, S; Plagge, T; Reichardt, C L; Rest, A; Ruel, J; Ruhl, J E; Sharon, K; Schaffer, K K; Shaw, L; Shirokoff, E; Spilker, J S; Stalder, B; Staniszewski, Z; Stark, A A; Story, K; Vanderlinde, K; Welikala, N; Williamson, R

    2013-03-21

    In the past decade, our understanding of galaxy evolution has been revolutionized by the discovery that luminous, dusty starburst galaxies were 1,000 times more abundant in the early Universe than at present. It has, however, been difficult to measure the complete redshift distribution of these objects, especially at the highest redshifts (z > 4). Here we report a redshift survey at a wavelength of three millimetres, targeting carbon monoxide line emission from the star-forming molecular gas in the direction of extraordinarily bright millimetre-wave-selected sources. High-resolution imaging demonstrates that these sources are strongly gravitationally lensed by foreground galaxies. We detect spectral lines in 23 out of 26 sources and multiple lines in 12 of those 23 sources, from which we obtain robust, unambiguous redshifts. At least 10 of the sources are found to lie at z > 4, indicating that the fraction of dusty starburst galaxies at high redshifts is greater than previously thought. Models of lens geometries in the sample indicate that the background objects are ultra-luminous infrared galaxies, powered by extreme bursts of star formation.

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

    NASA Technical Reports Server (NTRS)

    Hinshaw, Gary F.

    2009-01-01

    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 approximately 1100. Data from the first five 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.

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

    NASA Technical Reports Server (NTRS)

    Hinshaw, Gary F.

    2008-01-01

    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 approximately 1100. Data from the first five 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 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.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed

    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.

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

    SciTech Connect

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

    2009-02-15

    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 ofmore » 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.« less

  6. The carbon cycle on early Earth--and on Mars?

    PubMed

    Grady, Monica M; Wright, Ian

    2006-10-29

    One of the goals of the present Martian exploration is to search for evidence of extinct (or even extant) life. This could be redefined as a search for carbon. The carbon cycle (or, more properly, cycles) on Earth is a complex interaction among three reservoirs: the atmosphere; the hydrosphere; and the lithosphere. Superimposed on this is the biosphere, and its presence influences the fixing and release of carbon in these reservoirs over different time-scales. The overall carbon balance is kept at equilibrium on the surface by a combination of tectonic processes (which bury carbon), volcanism (which releases it) and biology (which mediates it). In contrast to Earth, Mars presently has no active tectonic system; neither does it possess a significant biosphere. However, these observations might not necessarily have held in the past. By looking at how Earth's carbon cycles have changed with time, as both the Earth's tectonic structure and a more sophisticated biology have evolved, and also by constructing a carbon cycle for Mars based on the carbon chemistry of Martian meteorites, we investigate whether or not there is evidence for a Martian biosphere.

  7. The carbon cycle on early Earth—and on Mars?

    PubMed Central

    Grady, Monica M; Wright, Ian

    2006-01-01

    One of the goals of the present Martian exploration is to search for evidence of extinct (or even extant) life. This could be redefined as a search for carbon. The carbon cycle (or, more properly, cycles) on Earth is a complex interaction among three reservoirs: the atmosphere; the hydrosphere; and the lithosphere. Superimposed on this is the biosphere, and its presence influences the fixing and release of carbon in these reservoirs over different time-scales. The overall carbon balance is kept at equilibrium on the surface by a combination of tectonic processes (which bury carbon), volcanism (which releases it) and biology (which mediates it). In contrast to Earth, Mars presently has no active tectonic system; neither does it possess a significant biosphere. However, these observations might not necessarily have held in the past. By looking at how Earth's carbon cycles have changed with time, as both the Earth's tectonic structure and a more sophisticated biology have evolved, and also by constructing a carbon cycle for Mars based on the carbon chemistry of Martian meteorites, we investigate whether or not there is evidence for a Martian biosphere. PMID:17008211

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

    PubMed

    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.

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

    PubMed

    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.

  10. The "Carbon-Neutral University"--A Study from Germany

    ERIC Educational Resources Information Center

    Udas, Erica; Wölk, Monique; Wilmking, Martin

    2018-01-01

    Purpose: Nowadays, several higher education institutions around the world are integrating sustainability topics into their daily operations, functionality and education systems. This paper presents a case study from a pilot project implemented by the Ernst-Moritz-Arndt-Universität Greifswald (hereafter, Greifswald University), Germany on its way…

  11. An early-branching microbialite cyanobacterium forms intracellular carbonates.

    PubMed

    Couradeau, Estelle; Benzerara, Karim; Gérard, Emmanuelle; Moreira, David; Bernard, Sylvain; Brown, Gordon E; López-García, Purificación

    2012-04-27

    Cyanobacteria have affected major geochemical cycles (carbon, nitrogen, and oxygen) on Earth for billions of years. In particular, they have played a major role in the formation of calcium carbonates (i.e., calcification), which has been considered to be an extracellular process. We identified a cyanobacterium in modern microbialites in Lake Alchichica (Mexico) that forms intracellular amorphous calcium-magnesium-strontium-barium carbonate inclusions about 270 nanometers in average diameter, revealing an unexplored pathway for calcification. Phylogenetic analyses place this cyanobacterium within the deeply divergent order Gloeobacterales. The chemical composition and structure of the intracellular precipitates suggest some level of cellular control on the biomineralization process. This discovery expands the diversity of organisms capable of forming amorphous calcium carbonates.

  12. Sugars as the Optimal Biosynthetic Carbon Substrate of Aqueous Life throughout the Universe

    NASA Technical Reports Server (NTRS)

    Weber, Arthur L.

    1999-01-01

    Our previous analysis of the energetics of metabolism showed that both the biosynthesis of amino acids and lipids from sugars, and the fermentation of organic substrates, were energetically driven by electron transfer reactions resulting in carbon redox disproportionation (Weber 1997). Redox disproportionation -- the spontaneous (energetically favorable) direction of carbon group transformation in biosynthesis -- is brought about and driven by the energetically downhill transfer of electron pairs from more oxidized carbon groups (with lower half-cell reduction potentials) to more reduced carbon groups (with higher half-cell reduction potentials). In this report, we compare the redox and kinetic properties of carbon groups in order to evaluate the relative biosynthetic capability of organic substrates, and to identify the optimal biosubstrate. This analysis revealed that sugars (monocarbonyl alditols) are the optimal biosynthetic substrate because they contain the maximum number of biosynthetically useful .high energy electrons/carbon atom , while still containing a single carbonyl group needed to kinetically facilitate their conversion to useful biosynthetic intermediates. This conclusion applies to aqueous life throughout the Universe because it is based on invariant aqueous carbon chemistry -- primarily, the universal reduction potentials of carbon groups.

  13. Sugars as the optimal biosynthetic carbon substrate of aqueous life throughout the universe

    NASA Technical Reports Server (NTRS)

    Weber, A. L.

    2000-01-01

    Our previous analysis of the energetics of metabolism showed that both the biosynthesis of amino acids and lipids from sugars, and the fermentation of organic substrates, were energetically driven by electron transfer reactions resulting in carbon redox disproportionation (Weber, 1997). Redox disproportionation--the spontaneous (energetically favorable) direction of carbon group transformation in biosynthesis--is brought about and driven by the energetically downhill transfer of electron pairs from more oxidized carbon groups (with lower half-cell reduction potentials) to more reduced carbon groups (with higher half-cell reduction potentials). In this report, we compare the redox and kinetic properties of carbon groups in order to evaluate the relative biosynthetic capability of organic substrates, and to identify the optimal biosubstrate. This analysis revealed that sugars (monocarbonyl alditols) are the optimal biosynthetic substrate because they contain the maximum number of biosynthetically useful high energy electrons/carbon atom while still containing a single carbonyl group needed to kinetically facilitate their conversion to useful biosynthetic intermediates. This conclusion applies to aqueous life throughout the Universe because it is based on invariant aqueous carbon chemistry--primarily, the universal reduction potentials of carbon groups.

  14. Early Triassic fluctuations of the global carbon cycle: New evidence from paired carbon isotopes in the western USA basin

    NASA Astrophysics Data System (ADS)

    Caravaca, Gwénaël; Thomazo, Christophe; Vennin, Emmanuelle; Olivier, Nicolas; Cocquerez, Théophile; Escarguel, Gilles; Fara, Emmanuel; Jenks, James F.; Bylund, Kevin G.; Stephen, Daniel A.; Brayard, Arnaud

    2017-07-01

    In the aftermath of the catastrophic end-Permian mass extinction, the Early Triassic records recurrent perturbations in the carbon isotope signal, most notably during the Smithian and through the Smithian/Spathian Boundary (SSB; 1.5 myr after the Permian/Triassic boundary), which show some of the largest excursions of the Phanerozoic. The late Smithian also corresponds to major biotic turnovers and environmental changes, such as temperature fluctuations, that deeply impacted the recovery after the end-Permian mass extinction. Here we document the paired carbon isotope signal along with an analysis of the trace and major elements at the long-known Hot Springs section (southeastern Idaho, USA). This section records Early Triassic sediments from the Griesbachian-Dienerian up to the lower Spathian. We show that the organic and carbonate δ13C variations mirror the signals identified at a global scale. Particularly, the middle Smithian-SSB event represented by a negative-positive isotopic couplet is well identified and is not of diagenetic origin. We also document a positive excursion potentially corresponding to the Dienerian/Smithian Boundary. Observed Smithian-Spathian excursions are recorded similarly in both the organic and carbonate reservoirs, but the organic matter signal systematically shows unexpectedly dampened variations compared to its carbonate counterpart. Additionally, we show that variations in the net isotopic effect (i.e., Δ13C) probably resulted from a complex set of forcing parameters including either a mixing between terrestrial and marine organic matter depending on the evolution of the depositional setting, or variations in the biological fractionation. We establish that the Δ13C signal cannot be directly related to CO2-driven temperature variations at Hot Springs. Even though the carbon isotope signal mirrors the Early Triassic variations known at the global scale, the Hot Springs signal probably also reflects local influences on the carbon

  15. Divergent response of the neritic carbonate factory to environmental changes during the Early Bajocian Event

    NASA Astrophysics Data System (ADS)

    Bodin, Stephane; Hönig, Martin; Krencker, Francois-Nicolas; Danisch, Jan; Kabiri, Lahcen

    2017-04-01

    The Early Bajocian witnessed a global environmental perturbation, characterized by faunal and floral turnovers and a positive carbon isotope excursion. In Italy, this environmental perturbation coincided with an eutrophication event and a carbonate crisis, but this has so far not been adequately reported from other settings, leaving doubt about the extent and nature of these phenomena. Here, we are reporting on an extensive neritic carbonate factory demise that occurs in the upper Lower Bajocian of the Central High Atlas of Morocco, more precisely in the upper Propinquans - lower Humphriesianum Zones. This demise coincided with the acme of the global carbon isotope perturbation, recorded by a 3‰ positive carbon isotope excursion in the bulk organic matter of Morocco. Recovery of the neritic carbonate system occurs during the Early to Late Bajocian transition. The duration of the neritic carbonate factory demise was therefore in the order of 1 Myr. Furthermore, we observe that the Lower Bajocian of Morocco is relatively enriched in arenitic siliciclastic deposits, suggesting increased weathering and nutrient levels along the northwestern margin of Africa during the Early Bajocian. However, comparison with neighboring European basins highlights the non-uniqueness and different timing of the response of shallow-water carbonates to the Early Bajocian environmental perturbations, as some regions present no sign of carbonate factory crisis. Hence, we postulate that local factors were important in mediating the response of neritic carbonate factories to this global environmental perturbation. We notably highlight the role of large Early Bajocian sea-level fluctuation as a trigger for carbonate factory change and demise in Morocco. Indeed, in the Central High Atlas Basin, transgressive intervals are seeing the development of a mud-dominated carbonate factory whereas regressive intervals are associated with grain-dominated carbonate factory. We speculate that the

  16. Towards a universal model for carbon dioxide uptake by plants

    DOE PAGES

    Wang, Han; Prentice, I. Colin; Keenan, Trevor F.; ...

    2017-09-04

    Gross primary production (GPP) - the uptake of carbon dioxide (CO 2) by leaves, and its conversion to sugars by photosynthesis - is the basis for life on land. Earth System Models (ESMs) incorporating the interactions of land ecosystems and climate are used to predict the future of the terrestrial sink for anthropogenic CO 2. ESMs require accurate representation of GPP. However, current ESMs disagree on how GPP responds to environmental variations, suggesting a need for a more robust theoretical framework for modelling. Here in this work, we focus on a key quantity for GPP, the ratio of leaf internalmore » to external CO 2 (χ). χ is tightly regulated and depends on environmental conditions, but is represented empirically and incompletely in today's models. We show that a simple evolutionary optimality hypothesis predicts specific quantitative dependencies of χ on temperature, vapour pressure deficit and elevation; and that these same dependencies emerge from an independent analysis of empirical χ values, derived from a worldwide dataset of >3,500 leaf stable carbon isotope measurements. A single global equation embodying these relationships then unifies the empirical light-use efficiency model with the standard model of C 3 photosynthesis, and successfully predicts GPP measured at eddy-covariance flux sites. This success is notable given the equation's simplicity and broad applicability across biomes and plant functional types. Finally, it provides a theoretical underpinning for the analysis of plant functional coordination across species and emergent properties of ecosystems, and a potential basis for the reformulation of the controls of GPP in next-generation ESMs.« less

  17. Towards a universal model for carbon dioxide uptake by plants

    SciTech Connect

    Wang, Han; Prentice, I. Colin; Keenan, Trevor F.

    Gross primary production (GPP) - the uptake of carbon dioxide (CO 2) by leaves, and its conversion to sugars by photosynthesis - is the basis for life on land. Earth System Models (ESMs) incorporating the interactions of land ecosystems and climate are used to predict the future of the terrestrial sink for anthropogenic CO 2. ESMs require accurate representation of GPP. However, current ESMs disagree on how GPP responds to environmental variations, suggesting a need for a more robust theoretical framework for modelling. Here in this work, we focus on a key quantity for GPP, the ratio of leaf internalmore » to external CO 2 (χ). χ is tightly regulated and depends on environmental conditions, but is represented empirically and incompletely in today's models. We show that a simple evolutionary optimality hypothesis predicts specific quantitative dependencies of χ on temperature, vapour pressure deficit and elevation; and that these same dependencies emerge from an independent analysis of empirical χ values, derived from a worldwide dataset of >3,500 leaf stable carbon isotope measurements. A single global equation embodying these relationships then unifies the empirical light-use efficiency model with the standard model of C 3 photosynthesis, and successfully predicts GPP measured at eddy-covariance flux sites. This success is notable given the equation's simplicity and broad applicability across biomes and plant functional types. Finally, it provides a theoretical underpinning for the analysis of plant functional coordination across species and emergent properties of ecosystems, and a potential basis for the reformulation of the controls of GPP in next-generation ESMs.« less

  18. News & Views Evaluation of Projects for Basic Research of Scientific Instruments in 2008 Completed NSFC Former President Tang Ao-qing Passed Away Professor Tang Aoqing and NSFC Carbon Nanotube Film-Based Speaker Developed in Tsinghua University Dinosaur Footprint Fossils Discovered in Xinjiang New Method for Early Cancer Diagnosis New Progress Achieved by NSFC Project in Basic Research of Black Hole Physics New progress in Organic FET 67 NSFC-RFBR Cooperative Projects Approved for 2008 Spin Configuration and Super-exchange Mechanism in Molecular Magnets Observed NSFC Strengthens its Funding in Wenchuan Concerns Go to Disaster's Impact on Economy and Emergency Response Thirty-seven NSFC-KOSEF Cooperative Projects Approved

    NASA Astrophysics Data System (ADS)

    2008-01-01

    Evaluation of Projects for Basic Research of Scientific Instruments in 2008 Completed NSFC Former President Tang Ao-qing Passed Away Professor Tang Aoqing and NSFC Carbon Nanotube Film-Based Speaker Developed in Tsinghua University Dinosaur Footprint Fossils Discovered in Xinjiang New Method for Early Cancer Diagnosis New Progress Achieved by NSFC Project in Basic Research of Black Hole Physics New progress in Organic FET 67 NSFC-RFBR Cooperative Projects Approved for 2008 Spin Configuration and Super-exchange Mechanism in Molecular Magnets Observed NSFC Strengthens its Funding in Wenchuan Concerns Go to Disaster's Impact on Economy and Emergency Response Thirty-seven NSFC-KOSEF Cooperative Projects Approved

  19. Outcomes for Students on a Fast Track to College: Early College Entrance Programs at the University of Washington

    ERIC Educational Resources Information Center

    Hertzog, Nancy B.; Chung, Rachel U.

    2015-01-01

    Radical acceleration from middle school to university is an unusual option in the United States. The Early Entrance Program and the University of Washington (UW) Academy for Young Scholars housed in the Halbert and Nancy Robinson Center for Young Scholars are two of only 21 early university entrance programs offered in the United States. Due to…

  20. Universal HPLC Detector for Hydrophilic Organic Compounds by Means of Total Organic Carbon Detection.

    PubMed

    Ohira, Shin-Ichi; Kaneda, Kyosuke; Matsuzaki, Toru; Mori, Shuta; Mori, Masanobu; Toda, Kei

    2018-06-05

    Most quantifications are achieved by comparison of the signals obtained with the sample to those from a standard. Thus, the purity and stability of the standard are key in chemical analysis. Furthermore, if an analyte standard cannot be obtained, quantification cannot be achieved, even if the chemical structures are identified by a qualification method (e.g., high-resolution mass spectrometry). Herein, we describe a universal and analyte standard-free detector for aqueous-eluent-based high-performance liquid chromatography. This universal carbon detector (UCD) was developed based on total organic carbon detection. Separated analytes were oxidized in-line and converted to carbon dioxide (CO 2 ). Generated CO 2 was transferred into the gas phase and collected into ultrapure water, which was followed by conductivity detection. The system can be applied as a HPLC detector that does not use an organic solvent as an eluent. The system can be calibrated with a primary standard of sodium bicarbonate for organic compounds. The universality and quantification were evaluated with organic compounds, including organic acids, sugars, and amino acids. Furthermore, the system was successfully applied to evaluation of the purity of formaldehyde in formalin solution, and determination of sugars in juices. The results show the universal carbon detector has good universality and can quantify many kinds of organic compounds with a single standard such as sodium bicarbonate.

  1. Gravitational Wave Astronomy Using Pulsars: Massive Black Hole Mergers and the Early Universe

    DTIC Science & Technology

    2010-01-01

    Gravitational Wave Astronomy Using Pulsars : Massive Black Hole Mergers & the Early Universe A White Paper for the Astronomy & Astrophysics Decadal...COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Gravitational Wave Astronomy Using Pulsars : Massive Black Hole Mergers & the Early...theory of general relativity. Using a collection of millisecond pulsars as high-precision clocks, the nHz band of this radiation is likely to be detected

  2. The carbon or silicon colonization of the universe?

    PubMed

    Parkinson, Bob

    2005-01-01

    At the time of the Apollo Programme, a first human mission to Mars was proposed as early as 1984 with the argument that the higher costs of human exploration would be more than justified by the increased effectiveness of human explorers. This was based on the Apollo experience, where "ground truth" measurements and sampling provided the basis for subsequent unmanned exploration of the Solar System. A human Mars mission is now not seen until 2030, at the end of a series of increasingly sophisticated unmanned probes. Each robot mission not only teaches us something about Mars, but also through experience increases our capabilities for the unmanned exploration of that planet. As a consequence, what a human mission would have to do becomes progressively more demanding. Any extended plan for the human exploration of Space will tend to be overtaken by advances in technology, and if this is not factored into the scenario the proposals will become progressively unrealistic.

  3. Universal interaction-driven gap in metallic carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Senger, Mitchell J.; McCulley, Daniel R.; Lotfizadeh, Neda; Deshpande, Vikram V.; Minot, Ethan D.

    2018-02-01

    Suspended metallic carbon nanotubes (m-CNTs) exhibit a remarkably large transport gap that can exceed 100 meV. Both experiment and theory suggest that strong electron-electron interactions play a crucial role in generating this electronic structure. To further understand this strongly interacting system, we have performed electronic measurements of suspended m-CNTs with known diameter and chiral angle. Spectrally resolved photocurrent microscopy was used to determine m-CNT structure. The room-temperature electrical characteristics of 18 individually contacted m-CNTs were compared to their respective diameter and chiral angle. At the charge neutrality point, we observe a peak in m-CNT resistance that scales exponentially with inverse diameter. Using a thermally activated transport model, we estimate that the transport gap is (450 meV nm)/D , where D is CNT diameter. We find no correlation between the gap and the CNT chiral angle. Our results add important constraints to theories attempting to describe the electronic structure of m-CNTs.

  4. Amyloid-carbon hybrid membranes for universal water purification

    NASA Astrophysics Data System (ADS)

    Bolisetty, Sreenath; Mezzenga, Raffaele

    2016-04-01

    Industrial development, energy production and mining have led to dramatically increased levels of environmental pollutants such as heavy metal ions, metal cyanides and nuclear waste. Current technologies for purifying contaminated waters are typically expensive and ion specific, and there is therefore a significant need for new approaches. Here, we report inexpensive hybrid membranes made from protein amyloid fibrils and activated porous carbon that can be used to remove heavy metal ions and radioactive waste from water. During filtration, the concentration of heavy metal ions drops by three to five orders of magnitude per passage and the process can be repeated numerous times. Notably, their efficiency remains unaltered when filtering several ions simultaneously. The performance of the membrane is enabled by the ability of the amyloids to selectively absorb heavy metal pollutants from solutions. We also show that our membranes can be used to recycle valuable heavy metal contaminants by thermally reducing ions trapped in saturated membranes, leading to the creation of elemental metal nanoparticles and films.

  5. Persistence of carbon release events through the peak of early Eocene global warmth

    NASA Astrophysics Data System (ADS)

    Kirtland Turner, Sandra; Sexton, Philip F.; Charles, Christopher D.; Norris, Richard D.

    2014-10-01

    The Early Eocene Climatic Optimum (53-50 million years ago) was preceded by approximately six million years of progressive global warming. This warming was punctuated by a series of rapid hyperthermal warming events triggered by the release of greenhouse gases. Over these six million years, the carbon isotope record suggests that the events became more frequent but smaller in magnitude. This pattern has been suggested to reflect a thermodynamic threshold for carbon release that was more easily crossed as global temperature rose, combined with a decrease in the size of carbon reservoirs during extremely warm conditions. Here we present a continuous, 4.25-million-year-long record of the stable isotope composition of carbonate sediments from the equatorial Atlantic, spanning the peak of early Eocene global warmth. A composite of this and pre-existing records shows that the carbon isotope excursions that identify the hyperthermals exhibit continuity in magnitude and frequency throughout the approximately 10-million-year period covering the onset, peak and termination of the Early Eocene Climate Optimum. We suggest that the carbon cycle processes behind these events, excluding the largest event, the Palaeocene-Eocene Thermal Maximum (about 56 million years ago), were not exceptional. Instead, we argue that the hyperthermals may reflect orbital forcing of the carbon cycle analogous to the mechanisms proposed to operate in the cooler Oligocene and Miocene.

  6. Early Age Carbonation Heat and Products of Tricalcium Silicate Paste Subject to Carbon Dioxide Curing.

    PubMed

    Li, Zhen; He, Zhen; Shao, Yixin

    2018-05-04

    This paper presents a study on the carbonation reaction heat and products of tricalcium silicate (C₃S) paste exposed to carbon dioxide (CO₂) for rapid curing. Reaction heat was measured using a retrofitted micro-calorimeter. The highest heat flow of a C₃S paste subject to carbonation curing was 200 times higher than that by hydration, and the cumulative heat released by carbonation was three times higher. The compressive strength of a C₃S paste carbonated for 2 h and 24 h was 27.5 MPa and 62.9 MPa, respectively. The 24-h carbonation strength had exceeded the hydration strength at 28 days. The CO₂ uptake of a C₃S paste carbonated for 2 h and 24 h was 17% and 26%, respectively. The X-ray diffraction (XRD), transmission electron microscope coupled with energy dispersive spectrometer (TEM-EDS), and 29 Si magic angle spinning⁻nuclear magnetic resonance ( 29 Si MAS-NMR) results showed that the products of a carbonated C₃S paste were amorphous silica (SiO₂) and calcite crystal. There was no trace of calcium silicate hydrate (C⁻S⁻H) or other polymorphs of calcium carbonate (CaCO₃) detected.

  7. Early Age Carbonation Heat and Products of Tricalcium Silicate Paste Subject to Carbon Dioxide Curing

    PubMed Central

    Li, Zhen; He, Zhen; Shao, Yixin

    2018-01-01

    This paper presents a study on the carbonation reaction heat and products of tricalcium silicate (C3S) paste exposed to carbon dioxide (CO2) for rapid curing. Reaction heat was measured using a retrofitted micro-calorimeter. The highest heat flow of a C3S paste subject to carbonation curing was 200 times higher than that by hydration, and the cumulative heat released by carbonation was three times higher. The compressive strength of a C3S paste carbonated for 2 h and 24 h was 27.5 MPa and 62.9 MPa, respectively. The 24-h carbonation strength had exceeded the hydration strength at 28 days. The CO2 uptake of a C3S paste carbonated for 2 h and 24 h was 17% and 26%, respectively. The X-ray diffraction (XRD), transmission electron microscope coupled with energy dispersive spectrometer (TEM-EDS), and 29Si magic angle spinning–nuclear magnetic resonance (29Si MAS-NMR) results showed that the products of a carbonated C3S paste were amorphous silica (SiO2) and calcite crystal. There was no trace of calcium silicate hydrate (C–S–H) or other polymorphs of calcium carbonate (CaCO3) detected. PMID:29734681

  8. The Reluctant Academic: Early-Career Academics in a Teaching-Orientated University

    ERIC Educational Resources Information Center

    Gale, Helen

    2011-01-01

    This paper is based on research into academic identities amongst early-career academics in a UK post-1992, teaching-orientated university. Literature around academic identity suggests five major academic roles: teaching, research, management, writing and networking. However, this appears to be a picture of an established mid-career academic in a…

  9. On the proposed existence of an anti-gravity regime in the early universe

    NASA Astrophysics Data System (ADS)

    Pollock, M. D.

    1982-02-01

    In an interesting letter, Linde has recently suggested that, as a result of the behaviour of dense matter in the early Universe, the realization of an anti-gravity phase is possible, in principle, without the intervention of quantum gravity. Using the Friedman cosmological model, we amplify the discussion given by Linde and find a difficulty with his interpretation.

  10. Test Anxiety in Mathematics among Early Undergraduate Students in a British University in Malaysia

    ERIC Educational Resources Information Center

    Karjanto, Natanael; Yong, Su Ting

    2013-01-01

    The level of test anxiety in mathematics subjects among early undergraduate students at the University of Nottingham Malaysia Campus is studied in this article. The sample consists of 206 students taking several mathematics modules who completed the questionnaires on test anxiety just before they entered the venue for midterm examinations. The…

  11. Postsecondary Preparation and Remediation: Examining the Effect of the Early Assessment Program at California State University

    ERIC Educational Resources Information Center

    Howell, Jessica S.; Kurlaender, Michal; Grodsky, Eric

    2010-01-01

    In this paper we investigate how participation in the Early Assessment Program, which provides California high school juniors with information about their academic readiness for college-level work at California State University campuses, affects their college-going behavior and need for remediation in college. Using administrative records from…

  12. Preparedness to Teach: Experiences of the University of Ibadan Early Career Academics

    ERIC Educational Resources Information Center

    Udegbe, I. Bola

    2016-01-01

    This research examined the experiences of early career academics (ECAs) in terms of their preparedness to teach. Using a survey design involving 104 ECAs in a large Nigeria university, quantitative and qualitative data were obtained to address the research questions raised. Findings showed that (1) prior experience and training impacted on…

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

    NASA Technical Reports Server (NTRS)

    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.

  14. A Constructivist/Reflective Paradigm: A Model for the Early Childhood Program at Tuskegee University.

    ERIC Educational Resources Information Center

    Noori, Kathryn K.

    The Early Childhood Program in the Department of Curriculum, Instruction and Administration at Tuskegee University (Alabama) is described as a convergence of Jean Piaget's constructivism and John Dewey's progressivism. It is designed to provide preservice teachers with experiences that promote reflective practice and that view the learner as an…

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

    ERIC Educational Resources Information Center

    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…

  16. Nitrogen alters carbon dynamics during early succession in boreal forest

    Treesearch

    Steven D. Allison; Tracy B. Gartner; Michelle C. Mack; Krista McGuire; Kathleen Treseder

    2010-01-01

    Boreal forests are an important source of wood products, and fertilizers could be used to improve forest yields, especially in nutrient poor regions of the boreal zone. With climate change, fire frequencies may increase, resulting in a larger fraction of the boreal landscape present in early successional stages. Since most fertilization studies have focused on mature...

  17. A carbon dioxide/methane greenhouse atmosphere on early Mars

    NASA Technical Reports Server (NTRS)

    Brown, L. L.; Kasting, J. F.

    1993-01-01

    One explanation for the formation of fluvial surface features on early Mars is that the global average surface temperature was maintained at or above the freezing point of water by the greenhouse warming of a dense CO2 atmosphere; however, Kasting has shown that CO2 alone is insufficient because the formation of CO2 clouds reduces the magnitude of the greenhouse effect. It is possible that other gases, such as NH3 and CH4, were present in the early atmosphere of Mars and contributed to the greenhouse effect. Kasting et al. investigated the effect of NH3 in a CO2 atmosphere and calculated that an NH3 mixing ratio of approximately 5 x 10 (exp -4) by volume, combined with a CO2 partial pressure of 4-5 bar, could generate a global average surface temperature of 273 K near 3.8 b.y. ago when the fluvial features are believed to have formed. Atmospheric NH3 is photochemically converted to N2 by ultraviolet radiation at wavelengths shortward of 230 nm; maintenance of sufficient NH3 concentrations would therefore require a source of NH3 to balance the photolytic destruction. We have used a one-dimensional photochemical model to estimate the magnitude of the NH3 source required to maintain a given NH3 concentration in a dense CO2 atmosphere. We calculate that an NH3 mixing ratio of 10(exp -4) requires a flux of NH3 on the order of 10(exp 12) molecules /cm-s. This figure is several orders of magnitude greater than estimates of the NH3 flux on early Mars; thus it appears that NH3 with CO2 is not enough to keep early Mars warm.

  18. Early snowmelt significantly enhances boreal springtime carbon uptake

    PubMed Central

    Pulliainen, Jouni; Aurela, Mika; Laurila, Tuomas; Aalto, Tuula; Takala, Matias; Salminen, Miia; Kulmala, Markku; Barr, Alan; Heimann, Martin; Lindroth, Anders; Laaksonen, Ari; Derksen, Chris; Mäkelä, Annikki; Markkanen, Tiina; Lemmetyinen, Juha; Susiluoto, Jouni; Dengel, Sigrid; Mammarella, Ivan; Tuovinen, Juha-Pekka; Vesala, Timo

    2017-01-01

    We determine the annual timing of spring recovery from space-borne microwave radiometer observations across northern hemisphere boreal evergreen forests for 1979–2014. We find a trend of advanced spring recovery of carbon uptake for this period, with a total average shift of 8.1 d (2.3 d/decade). We use this trend to estimate the corresponding changes in gross primary production (GPP) by applying in situ carbon flux observations. Micrometeorological CO2 measurements at four sites in northern Europe and North America indicate that such an advance in spring recovery would have increased the January–June GPP sum by 29 g⋅C⋅m−2 [8.4 g⋅C⋅m−2 (3.7%)/decade]. We find this sensitivity of the measured springtime GPP to the spring recovery to be in accordance with the corresponding sensitivity derived from simulations with a land ecosystem model coupled to a global circulation model. The model-predicted increase in springtime cumulative GPP was 0.035 Pg/decade [15.5 g⋅C⋅m−2 (6.8%)/decade] for Eurasian forests and 0.017 Pg/decade for forests in North America [9.8 g⋅C⋅m−2 (4.4%)/decade]. This change in the springtime sum of GPP related to the timing of spring snowmelt is quantified here for boreal evergreen forests. PMID:28973918

  19. Carbon Cycle Dynamics through the Early Eocene Climatic Optimum: Orbital Couplings to Lacustrine Cycling

    NASA Astrophysics Data System (ADS)

    Rosengard, S. Z.; Grogan, D. S.; Whiteside, J. H.; van Keuren, M.; Musher, D.

    2010-12-01

    The early Eocene represents the most recent hothouse climate state of Earth history, a period during which Earth’s surface temperatures warmed and reached a steady peak at the Early Eocene Climatic Optimum (EECO), 53.5-50 Ma. Interspersed through the primary warming interval were several hyperthermals, or rapid peaks in surface temperature and pulses of carbon dioxide into the atmosphere, followed by rapid declines, lasting 10^4 to 10^5 years. Various hypotheses have been offered to explain the climatic triggers during the hothouse interval, including changes in ocean circulation, methane release from hydrates, volcanism, and turnover of terrestrial organic matter, implicating various couplings and feedbacks in the global carbon cycle. The present study investigates the prevailing changes in carbon cycle dynamics that occurred during a specific subinterval of the Early Eocene Climatic Optimum. We sampled a carbon-rich 300-ft ( 1100 kyr) section of lacustrine Green River Formation sediments from the TOSCO core in the Uinta Basin at a one-foot resolution for organic carbon content and δ^{13}C. The compiled data comprise a high-resolution profile of total organic carbon and isotopic organic carbon composition through the section, showing cyclic patterns that we hypothesize reflect orbital signals. Bulk isotopic carbon and shale oil measurements from an earlier Fischer Assay across TOSCO’s entire 1030-ft core were then filtered using the expected frequency of a 23-kyr precession cycle. The overlaid cycles reveal δ^{13}C and oil content to be anti-phase through the 300-ft section, except for an interval of 50 feet (180 kyr) from the Mahogany Zone to the B-groove of the core, where the two measurements are in-phase. Given that shale oil, a proxy for lake primary productivity and carbon burial, and δ^{13}C typically correlate inversely, this short, 180-kyr interval of in-phase variation suggests a significant alteration in the local carbon cycle. These preliminary

  20. Evolution of domain walls in the early universe. Ph.D. Thesis - Chicago Univ.

    NASA Technical Reports Server (NTRS)

    Kawano, Lawrence

    1989-01-01

    The evolution of domain walls in the early universe is studied via 2-D computer simulation. The walls are initially configured on a triangular lattice and then released from the lattice, their evolution driven by wall curvature and by the universal expansion. The walls attain an average velocity of about 0.3c and their surface area per volume (as measured in comoving coordinates) goes down with a slope of -1 with respect to conformal time, regardless of whether the universe is matter or radiation dominated. The additional influence of vacuum pressure causes the energy density to fall away from this slope and steepen, thus allowing a situation in which domain walls can constitute a significant portion of the energy density of the universe without provoking an unacceptably large perturbation upon the microwave background.

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

    NASA Technical Reports Server (NTRS)

    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.

  2. What do we really know about early diagenesis of non-marine carbonates?

    NASA Astrophysics Data System (ADS)

    De Boever, Eva; Brasier, Alexander T.; Foubert, Anneleen; Kele, Sándor

    2017-11-01

    Non-marine carbonate rocks including cave, spring, stream, calcrete and lacustrine-palustrine sediments, are susceptible to early diagenetic processes. These can profoundly alter the carbonate fabric and affect paleoclimatic proxies. This review integrates recent insights into diagenesis of non-marine carbonates and in particular the variety of early diagenetic processes, and presents a conceptual framework to address them. With ability to study at smaller and smaller scales, down to nanometers, one can now observe diagenesis taking place the moment initial precipitates have formed, and continuing thereafter. Diagenesis may affect whole rocks, but it typically starts in nano- and micro-environments. The potential for diagenetic alteration depends on the reactivity of the initial precipitate, commonly being metastable phases like vaterite, Ca-oxalates, hydrous Mg-carbonates and aragonite with regard to the ambient fluid. Furthermore, organic compounds commonly play a crucial role in hosting these early transformations. Processes like neomorphism (inversion and recrystallization), cementation and replacement generally result in an overall coarsening of the fabric and homogenization of the wide range of complex, primary microtextures. If early diagenetic modifications are completed in a short time span compared to the (annual to millennial) time scale of interest, then recorded paleoenvironmental signals and trends could still acceptably reflect original, depositional conditions. However, even compact, non-marine carbonate deposits may behave locally and temporarily as open systems to crystal-fluid exchange and overprinting of one or more geochemical proxies is not unexpected. Looking to the future, relatively few studies have examined the behaviour of promising geochemical records, such as clumped isotope thermometry and (non-conventional) stable isotopes, in well-constrained diagenetic settings. Ongoing and future in-vitro and in-situ experimental approaches will

  3. Spatial distribution of carbon dust in the early solar nebula and the carbon content of planetesimals

    NASA Astrophysics Data System (ADS)

    Gail, Hans-Peter; Trieloff, Mario

    2017-09-01

    Context. A high fraction of carbon bound in solid carbonaceous material is observed to exist in bodies formed in the cold outskirts of the solar nebula, while bodies in the region of terrestrial planets contain only very small mass fractions of carbon. Most of the solid carbon component is lost and converted into CO during the spiral-in of matter as the Sun accretes matter from the solar nebula. Aims: We study the fate of the carbonaceous material that entered the proto-solar disc by comparing the initial carbon abundance in primitive solar system material and the abundance of residual carbon in planetesimals and planets in the asteroid belt and the terrestrial planet region. Methods: We constructed a model for the composition of the pristine carbonaceous material from observational data on the composition of the dust component in comets and of interplanetary dust particles and from published data on pyrolysis experiments. This material entered the inner parts of the solar nebula during the course of the build-up of the proto-sun by accreting matter from the proto-stellar disc. Based on a one-zone evolution model of the solar nebula, we studied the pyrolysis of the refractory and volatile organic component and the concomitant release of hydrocarbons of high molecular weight under quiescent conditions of disc evolution, while matter migrates into the central parts of the solar nebula. We also studied the decomposition and oxidation of the carbonaceous material during violent flash heating events, which are thought to be responsible for the formation of chondrules. To do this, we calculated pyrolysis and oxidation of the carbonaceous material in temperature spikes that were modeled according to cosmochemical models for the temperature history of chondrules. Results: We find that the complex hydrocarbon components of the carbonaceous material are removed from the disc matter in the temperature range between 250 and 400 K, but the amorphous carbon component survives to

  4. Mineralogy, early marine diagenesis, and the chemistry of shallow-water carbonate sediments

    NASA Astrophysics Data System (ADS)

    Higgins, J. A.; Blättler, C. L.; Lundstrom, E. A.; Santiago-Ramos, D. P.; Akhtar, A. A.; Crüger Ahm, A.-S.; Bialik, O.; Holmden, C.; Bradbury, H.; Murray, S. T.; Swart, P. K.

    2018-01-01

    Shallow-water carbonate sediments constitute the bulk of sedimentary carbonates in the geologic record and are widely used archives of Earth's chemical and climatic history. One of the main limitations in interpreting the geochemistry of ancient carbonate sediments is the potential for post-depositional diagenetic alteration. In this study, we use paired measurements of calcium (44Ca/40Ca or δ44Ca) and magnesium (26Mg/24Mg or δ26Mg) isotope ratios in sedimentary carbonates and associated pore-fluids as a tool to understand the mineralogical and diagenetic history of Neogene shallow-water carbonate sediments from the Bahamas and southwest Australia. We find that the Ca and Mg isotopic composition of bulk carbonate sediments at these sites exhibits systematic stratigraphic variability that is related to both mineralogy and early marine diagenesis. The observed variability in bulk sediment Ca isotopes is best explained by changes in the extent and style of early marine diagenesis from one where the composition of the diagenetic carbonate mineral is determined by the chemistry of the fluid (fluid-buffered) to one where the composition of the diagenetic carbonate mineral is determined by the chemistry of the precursor sediment (sediment-buffered). Our results indicate that this process, together with variations in carbonate mineralogy (aragonite, calcite, and dolomite), plays a fundamental and underappreciated role in determining the regional and global stratigraphic expressions of geochemical tracers (δ13C, δ18O, major, minor, and trace elements) in shallow-water carbonate sediments in the geologic record. Our results also provide evidence that a large shallow-water carbonate sink that is enriched in 44Ca can explain the mismatch between the δ44/40Ca value of rivers and deep-sea carbonate sediments and call into question the hypothesis that the δ44/40Ca value of seawater depends on the mineralogy of primary carbonate precipitations (e.g. 'aragonite seas' and

  5. Entropy production during an isothermal phase transition in the early universe

    NASA Astrophysics Data System (ADS)

    Kaempfer, B.

    The analytical model of Lodenquai and Dixit (1983) and of Bonometto and Matarrese (1983) of an isothermal era in the early universe is extended here to arbitrary temperatures. It is found that a sufficiently large supercooling gives rise to a large entropy production which may significantly dilute the primordial monopole or baryon to entropy ratio. Whether such large supercooling can be achieved depends on the characteristics of the nucleation process.

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

    NASA Astrophysics Data System (ADS)

    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 <δρ>/ρ depends on the coupling of Φ with δφ and the spectral index of its spectrum is 0.9483

  7. A nano universal joint made from curved double-walled carbon nanotubes

    SciTech Connect

    Cai, Kun; Cai, Haifang; Shi, Jiao

    2015-06-15

    A nano universal joint is constructed from curved double-wall carbon nanotubes with a short outer tube as stator and a long inner tube as a rotor. When one end of the rotor is driven (by a rotary motor) to rotate, the same rotational speed but with different rotational direction will be induced at the other end of the rotor. This mechanism makes the joint useful for designing a flexible nanodevice with an adjustable output rotational signal. The motion transmission effect of the universal joint is analyzed using a molecular dynamics simulation approach. In particular, the effects of three factors aremore » investigated. The first factor is the curvature of the stator, which produces a different rotational direction of the rotor at the output end. The second is the bonding conditions of carbon atoms on the adjacent tube ends of the motor and the rotor, sp{sup 1} or sp{sup 2} atoms, which create different attraction between the motor and the rotor. The third is the rotational speed of the motor, which can be considered as the input signal of the universal joint. It is noted that the rotor's rotational speed is usually the same as that of the motor when the carbon atoms on the adjacent ends of the motor and the rotor are sp{sup 1} carbon atoms. When they become the new sp{sup 2} atoms, the rotor experiences a jump in rotational speed from a lower value to that of the motor. The mechanism of drops in potential of the motor is revealed. If the carbon atoms on the adjacent ends are sp{sup 2} atoms, the rotor rotates more slowly than the motor, whereas the rotational speed is stable when driven by a higher speed motor.« less

  8. A nano universal joint made from curved double-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Cai, Kun; Cai, Haifang; Shi, Jiao; Qin, Qing H.

    2015-06-01

    A nano universal joint is constructed from curved double-wall carbon nanotubes with a short outer tube as stator and a long inner tube as a rotor. When one end of the rotor is driven (by a rotary motor) to rotate, the same rotational speed but with different rotational direction will be induced at the other end of the rotor. This mechanism makes the joint useful for designing a flexible nanodevice with an adjustable output rotational signal. The motion transmission effect of the universal joint is analyzed using a molecular dynamics simulation approach. In particular, the effects of three factors are investigated. The first factor is the curvature of the stator, which produces a different rotational direction of the rotor at the output end. The second is the bonding conditions of carbon atoms on the adjacent tube ends of the motor and the rotor, sp1 or sp2 atoms, which create different attraction between the motor and the rotor. The third is the rotational speed of the motor, which can be considered as the input signal of the universal joint. It is noted that the rotor's rotational speed is usually the same as that of the motor when the carbon atoms on the adjacent ends of the motor and the rotor are sp1 carbon atoms. When they become the new sp2 atoms, the rotor experiences a jump in rotational speed from a lower value to that of the motor. The mechanism of drops in potential of the motor is revealed. If the carbon atoms on the adjacent ends are sp2 atoms, the rotor rotates more slowly than the motor, whereas the rotational speed is stable when driven by a higher speed motor.

  9. Early carbon mobilization and radicle protrusion in maize germination.

    PubMed

    Sánchez-Linares, Luis; Gavilanes-Ruíz, Marina; Díaz-Pontones, David; Guzmán-Chávez, Fernando; Calzada-Alejo, Viridiana; Zurita-Villegas, Viridiana; Luna-Loaiza, Viridiana; Moreno-Sánchez, Rafael; Bernal-Lugo, Irma; Sánchez-Nieto, Sobeida

    2012-07-01

    Considerable amounts of information is available on the complex carbohydrates that are mobilized and utilized by the seed to support early seedling development. These events occur after radicle has protruded from the seed. However, scarce information is available on the role of the endogenous soluble carbohydrates from the embryo in the first hours of germination. The present work analysed how the soluble carbohydrate reserves in isolated maize embryos are mobilized during 6-24 h of water imbibition, an interval that exclusively embraces the first two phases of the germination process. It was found that sucrose constitutes a very significant reserve in the scutellum and that it is efficiently consumed during the time in which the adjacent embryo axis is engaged in an active metabolism. Sucrose transporter was immunolocalized in the scutellum and in vascular elements. In parallel, a cell-wall invertase activity, which hydrolyses sucrose, developed in the embryo axis, which favoured higher glucose uptake. Sucrose and hexose transporters were active in the embryo tissues, together with the plasma membrane H(+)-ATPase, which was localized in all embryo regions involved in both nutrient transport and active cell elongation to support radicle extension. It is proposed that, during the initial maize germination phases, a net flow of sucrose takes place from the scutellum towards the embryo axis and regions that undergo elongation. During radicle extension, sucrose and hexose transporters, as well as H(+)-ATPase, become the fundamental proteins that orchestrate the transport of nutrients required for successful germination.

  10. From Early Aspirations to Actual Attainment: The Effects of Economic Status and Educational Expectations on University Pursuit

    ERIC Educational Resources Information Center

    Wu, Ching-Ling; Bai, Haiyan

    2015-01-01

    This study investigated the effects of economic status and the educational expectations of significant others on early university aspirations and actual university attainment. The study analyzed two-wave longitudinal data collected from 1,595 Taiwanese students in their 9th grade in middle school and in their freshman year at universities. The…

  11. Re-Envisioning the Role of Universities in Early Childhood Teacher Education: Community Partnerships for 21st-Century Learning

    ERIC Educational Resources Information Center

    Kennedy, Adam S.; Heineke, Amy

    2014-01-01

    Despite contrasting views on the overlap of early childhood education and teacher education, opportunities abound for expanding the role of early childhood educators in broader teacher education discourse. University-based early childhood education and kindergarten-through-grade-12 teacher education share purposes, philosophies, and resources that…

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

    PubMed

    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.

  13. Earth's Early Biosphere and the Biogeochemical Carbon Cycle

    NASA Technical Reports Server (NTRS)

    DesMarais, David

    2004-01-01

    Our biosphere has altered the global environment principally by influencing the chemistry of those elements most important for life, e g., C, N, S, O, P and transition metals (e.g., Fe and Mn). The coupling of oxygenic photosynthesis with the burial in sediments of photosynthetic organic matter, and with the escape of H2 to space, has increased the state of oxidation of the Oceans and atmosphere. It has also created highly reduced conditions within sedimentary rocks that have also extensively affected the geochemistry of several elements. The decline of volcanism during Earth's history reduced the flow of reduced chemical species that reacted with photosynthetically produced O2. The long-term net accumulation of photosynthetic O2 via biogeochemical processes has profoundly influenced our atmosphere and biosphere, as evidenced by the O2 levels required for algae, multicellular life and certain modem aerobic bacteria to exist. When our biosphere developed photosynthesis, it tapped into an energy resource that was much larger than the energy available from oxidation-reduction reactions associated with weathering and hydrothermal activity. Today, hydrothermal sources deliver globally (0.13-1.1)x10(exp l2) mol yr(sup -1) of reduced S, Fe(2+), Mn(2+), H2 and CH4; this is estimated to sustain at most about (0.2-2)xl0(exp 12)mol C yr(sup -1) of organic carbon production by chemautotrophic microorganisms. In contrast, global photosynthetic productivity is estimated to be 9000x10(exp 12) mol C yr(sup -1). Thus, even though global thermal fluxes were greater in the distant geologic past than today, the onset of oxygenic photosynthesis probably increased global organic productivity by some two or more orders of magnitude. This enormous productivity materialized principally because oxygenic photosynthesizers unleashed a virtually unlimited supply of reduced H that forever freed life from its sole dependence upon abiotic sources of reducing power such as hydrothermal emanations

  14. An early deployment strategy for carbon capture, utilisation, and storage

    SciTech Connect

    Carter, L.D.

    2012-11-01

    This report describes the current use of CO2 for EOR, and discusses potential expansion of EOR using CO2 from power plants. Analysis of potential EOR development in the USA, where most current CO2-based EOR production takes place, indicates that relatively low cost, traditional sources of CO2 for EOR (CO2 domes and CO2 from natural gas processing plants) are insufficient to exploit the full potential of EOR. To achieve that full potential will require use of CO2 from combustion and gasification systems, such as fossil fuel power plants, where capture of CO2 is more costly. The cost of current CCUS systems,more » even with the revenue stream for sale of the CO2 for EOR, is too high to result in broad deployment of the technology in the near term. In the longer term, research and development may be sufficient to reduce CO2 capture costs to a point where CCUS would be broadly deployed. This report describes a case study of conditions in the USA to explore a financial incentive to promote early deployment of CCUS, providing a range of immediate benefits to society, greater likelihood of reducing the long-term cost of CCUS, and greater likelihood of broad deployment of CCUS and CCS in the long term. Additionally, it may be possible to craft such an incentive in a manner that its cost is more than offset by taxes flowing from increased domestic oil production. An example of such an incentive is included in this report.« less

  15. Origins and Missions of Two Early Land-Grant Colleges: Georgetown University and George Washington University. ASHE Annual Meeting 1980 Paper.

    ERIC Educational Resources Information Center

    Quigley, Martin S.

    The founding and missions of Georgetown University and George Washington University, two early land-grant colleges, are considered. The account is based partially on standard histories of the colleges, and other information comes from Congressional Records. Some understanding of why Congress took an interest in the founding and survival of…

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

    NASA Astrophysics Data System (ADS)

    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

  17. Early Stage Anodic Instability of Glassy Carbon Electrodes in Propylene Carbonate Solvent Containing Lithium Hexafluorophosphate.

    PubMed

    Carino, Emily V; Newman, Daniel J; Connell, Justin G; Kim, Chaerin; Brushett, Fikile R

    2017-10-31

    Irreversible changes to the morphology of glassy carbon (GC) electrodes at potentials between 3.5 and 4.5 V vs Li/Li + in propylene carbonate (PC) solvent containing lithium hexafluorophosphate (LiPF 6 ) are reported. Analysis of cyclic voltammetry (CV) experiments in the range of 3.0 to 6.0 V shows that the capacitance of the electrochemical double-layer increased irreversibly beginning at potentials as low as 3.5 V. These changes resulted from nonfaradaic interactions, and were not due to oxidative electrochemical decomposition of the electrode and electrolyte, anion intercalation, nor caused by the presence of water, a common impurity in organic electrolyte solutions. Atomic force microscopy (AFM) images revealed that increasing the potential of a bare GC surface from 3.0 to 4.5 V resulted in a 6× increase in roughness, in good agreement with the changes in double-layer capacitance. Treating the GC surface via exposure to trichloromethylsilane vapors resulted in a stable double-layer capacitance between 3.0 and 4.5 V, and this treatment also correlated with less roughening. These results inform future efforts aimed at controlling surface composition and morphology of carbon electrodes.

  18. Early Stage Anodic Instability of Glassy Carbon Electrodes in Propylene Carbonate Solvent Containing Lithium Hexafluorophosphate

    DOE PAGES

    Carino, Emily V.; Newman, Daniel J.; Connell, Justin G.; ...

    2017-09-19

    In this paper, irreversible changes to the morphology of glassy carbon (GC) electrodes at potentials between 3.5 and 4.5 V vs Li/Li + in propylene carbonate (PC) solvent containing lithium hexafluorophosphate (LiPF 6) are reported. Analysis of cyclic voltammetry (CV) experiments in the range of 3.0 to 6.0 V shows that the capacitance of the electrochemical double -layer increased irreversibly beginning at potentials as low as 3.5 V. These changes resulted from nonfaradaic interactions, and were not due to oxidative electrochemical decomposition of the electrode and electrolyte, anion intercalation, nor caused by the presence of water, a common impurity inmore » organic electrolyte solutions. Atomic force microscopy (AFM) images revealed that increasing the potential of a bare GC surface from 3.0 to 4.5 V resulted in a 6X increase in roughness, in good agreement with the changes in double -layer capacitance. Treating the GC surface via exposure to trichloromethylsilane vapors resulted in a stable double -layer capacitance between 3.0 and 4.5 V, and this treatment also correlated with less roughening. Lastly, these results inform future efforts aimed at controlling surface composition and morphology of carbon electrodes.« less

  19. Astronomical Constraints on the Duration of Early Jurassic Stages and Global Carbon Cycle and Climatic Perturbations

    NASA Astrophysics Data System (ADS)

    Ruhl, M.; Hesselbo, S. P.; Hinnov, L.; Jenkyns, H. C.; Storm, M.; Xu, W.; Riding, J. B.; Ullmann, C. V.

    2015-12-01

    The Early Jurassic (201.3 to 174.1 Ma) is bracketed by the end-Triassic mass extinction and global warming event, and the Toarcian-Aalenian shift to (global) icehouse conditions (McElwain et al., 1999; Hesselbo et al., 2002; Ruhl et al., 2011; Korte et al., in review). It is further marked by the early Toarcian Oceanic Anoxic Event (T-OAE), with possibly the largest exogenic carbon cycle perturbation of the Mesozoic and related perturbations in global geochemical cycles, climate and the environment, which are linked to large igneous province emplacement in the Karoo-Ferrar region (Jenkyns, 2010; Burgess et al., 2015). Furthermore, Early Jurassic continental rifting and the break-up of Pangaea and subsequent Early Jurassic opening of the Hispanic Corridor and Viking Strait respectively linked the equatorial Tethys Ocean to Eastern Panthalassa and the high-latitude Arctic Boreal realm. This initiated changes in (global) ocean currents and Earth's heat distribution and ultimately was followed by the opening of the proto-North Atlantic (Porter et al., 2013; Korte et al., in review). Here, we present high-resolution (sub-precession scale) elemental concentration data from the Mochras borehole (UK), which represents ~1300m of possibly the most complete and expanded lower Jurassic hemi-pelagic marine sedimentary archive known. We construct a floating ~9 Myr astronomical time-scale for the complete Early Jurassic Pliensbachian stage and biozones. Combined with radiometric and astrochronological constraints on early Jurassic stage boundaries, we construct a new Early Jurassic Time-Scale. With this we assess the duration and rate of change of early Jurassic global carbon cycle and climatic perturbations and we asses fundamental changes in the nature and expression of Early Jurassic long (100 - 1000 kyr) eccentricity cycles.

  20. Unstable Hadrons in Hot Hadron Gas in Laboratory and in the Early Universe

    NASA Astrophysics Data System (ADS)

    Kuznetsova, Inga; Rafelski, Johann

    2011-04-01

    We study kinetic master equations for reactions involving the formation and the natural decay of unstable particles in a thermal expanding hadronic gas in the laboratory and in the early Universe. We consider here for the first time the role of the decay channel of one (hadron resonance) into two daughter particles, and also by token of detailed balance the inverse process, fusion of two (thermal) particles into one. We obtain the thermal invariant reaction rate using as an input the free space (vacuum) decay time and show the medium quantum effects on π+π<->ρ reaction relaxation time. As another laboratory example we describe the K+K<->φ process in thermal expanding hadronic gas in heavy ions collisions. A particularly interesting application of our formalism is the 0̂<->γ+γ process in the early Universe. We also explore the fate of charged pions and the muon freeze-out in the Universe. Another interesting field of application of our formalism is the study of short lived hadronic resonances, which are in general not able to reach yield equilibrium. We study the evolution of hadron resonances in small drops of QGP and use the insight gained to generalize the dynamics to QED effects as well.

  1. Quantum Kinetics and the Zeno Ansatz: Sterile Neutrino Dark Matter in the Early Universe

    NASA Astrophysics Data System (ADS)

    Dvornikov, Olexiy V.

    We solved the quantum kinetic equations for the evolution of neutrino states in the early universe. Starting at high temperatures, we evolve neutrino states to observe the resonant conversion of active-to-sterile neutrinos in a lepton asymmetric (more neutrinos than anti-neutrinos) universe. We find that at high temperatures, the high neutrino scattering and oscillation rates enforce a local equilibrium that balances the growth of coherence at the oscillation rate and the damping of coherence through scattering. This equilibrium, which we call a "quantum kinetic equilibrium," appears to approximately hold throughout the neutrino evolution, from the initial conditions through resonances that may be non adiabatic. Using this quantum kinetic equilibrium informs a proper choice of the initial conditions of the neutrino state and the relaxation process that occurs to this equilibrium when the initial conditions (as are typically chosen in the literature) are not coincident with the equilibrium values. We also discuss how to use this equilibrium to reduce the computational expense of solving the full quantum kinetic equations for neutrino states evolving in the early universe.

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

    NASA Technical Reports Server (NTRS)

    Hinshaw, Gary F.

    2009-01-01

    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 approx. 1100. Data from the first five 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.

  3. Green Peas emit X-rays: Extreme Star Formation in Early Universe Analog Galaxies

    NASA Astrophysics Data System (ADS)

    Brorby, Matthew; Kaaret, Philip

    2017-01-01

    Luminous compact galaxies (LCGs), Lyman Alpha Emitters (LAEs), and Lyman Break Analog galaxies (LBAs) are all used as proxies for star-forming galaxies in the early Universe (z ≥ 6). The X-ray emission from such galaxies has been found to be elevated compared to other star-forming galaxies in our local Universe. It has been suggested that this may be due to the lower metallicity seen in these proxies to high-redshift galaxies and the elevated X-ray emission may affect the heating and Reionization evolution of the early Universe. Our previous studies have suggested the existence of an LX-SFR-metallicity plane for all star-forming galaxies. We present these results in the context of our newest Joint Chandra/HST study containing the first X-ray detection of the Green Pea galaxies, a population of compact starburst galaxies discovered by volunteers in the Galaxy Zoo Project (Cardamone+2009). The galaxies were given the name Green Peas due to their compact size and green appearance in the gri composite images from SDSS. The green color is caused by a strong [OIII]λ5007Å emission line, an indicator of recent star formation. We observed a few of the most promising candidates with joint Chandra/HST observation and discuss our findings here.

  4. Sentinel Lymph Node Detection Using Carbon Nanoparticles in Patients with Early Breast Cancer

    PubMed Central

    Lu, Jianping; Zeng, Yi; Chen, Xia; Yan, Jun

    2015-01-01

    Purpose Carbon nanoparticles have a strong affinity for the lymphatic system. The purpose of this study was to evaluate the feasibility of sentinel lymph node biopsy using carbon nanoparticles in early breast cancer and to optimize the application procedure. Methods Firstly, we performed a pilot study to demonstrate the optimized condition using carbon nanoparticles for sentinel lymph nodes (SLNs) detection by investigating 36 clinically node negative breast cancer patients. In subsequent prospective study, 83 patients with clinically node negative breast cancer were included to evaluate SLNs using carbon nanoparticles. Another 83 SLNs were detected by using blue dye. SLNs detection parameters were compared between the methods. All patients irrespective of the SLNs status underwent axillary lymph node dissection for verification of axillary node status after the SLN biopsy. Results In pilot study, a 1 ml carbon nanoparticles suspension used 10–15min before surgery was associated with the best detection rate. In subsequent prospective study, with carbon nanoparticles, the identification rate, accuracy, false negative rate was 100%, 96.4%, 11.1%, respectively. The identification rate and accuracy were 88% and 95.5% with 15.8% of false negative rate using blue dye technique. The use of carbon nanoparticles suspension showed significantly superior results in identification rate (p = 0.001) and reduced false-negative results compared with blue dye technique. Conclusion Our study demonstrated feasibility and accuracy of using carbon nanoparticles for SLNs mapping in breast cancer patients. Carbon nanoparticles are useful in SLNs detection in institutions without access to radioisotope. PMID:26296136

  5. What the Most Metal-poor Stars Tell Us About the Early Universe

    NASA Astrophysics Data System (ADS)

    Frebel, Anna

    2008-05-01

    The chemical evolution of the Galaxy and the early Universe is a key topic in modern astrophysics. The most metal-poor Galactic halo stars are now frequently used in an attempt to reconstruct the onset of the chemical and dynamical formation processes of the Galaxy. These stars are an easily-accessible local equivalent of the high-redshift Universe, and can thus be used to carry out field-field cosmology. The discovery of two astrophysically very important metal-poor objects has recently lead to a significant advance in the field. One object is the most iron-poor star yet found (with [Fe/H]=-5.4). The other stars displays the strongest known overabundances of heavy neutron-capture elements, such as uranium, and nucleo-chronometry yields a stellar age of 13 Gyr. Both stars already serve as benchmark objects for various theoretical studies with regard to nucleosynthesis processes in the early Galaxy. I will discuss how the abundance patterns of these and other metal-poor stars solidify and advance our understanding of the early Universe, and provide constraints on the nature of the first stars, as well as their explosion mechanisms and corresponding supernova nucleosynthesis yields. Large samples of these old objects are also employed to test theoretical predictions about the formation of the very first low-mass stars. In the near future, the combined power of near-field cosmology results with those of the next-generation facilities (e.g., MWA, JWST, GMT) may yield exceptional details about the formation processes of the first generations of stars and galaxies.

  6. A Multi-Faceted Study of Three Forms of Galactic Formation in the Early Universe

    NASA Astrophysics Data System (ADS)

    Jones, Gareth Christopher

    While observations of the early universe have focused on bright, highly starbursting galaxies, star formation activity in the early universe was dominated by main sequence galaxies. Observations of the former group have been accumulating for decades, but the latter are only recently observable using modern instruments. In this work, we apply the Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA) to observe specific examples of each galactic class, in order to explore three modes of galaxy formation: smooth accretion, satellite accretion, and massive mergers. Using the molecular gas tracer CO and a broad set of continuum measurements, we characterize the gas mass and distribution, star formation, and dust temperature of the two archetypal massively merging Hyper-Luminous IR Galaxies (HyLIRGs) BRI1202-0725 & BRI1335-0417. We then examine the [C II] emission of the Lyman-Break Galaxy (LBG) WMH5, which shows two infalling gas clouds, implying ongoing formation via filamentary accretion. Finally, we apply a classical suite of dynamical characterization tools to [C II] observations of three MS galaxies and three starbursts, resulting in rotation curves and dynamical masses for each. By examining each of these sources in detail, we find that galaxies in the early (i.e., z > 4) universe formed via a broad range of interactions, ranging from cold-mode accretion to major mergers. As these instruments continue observing, and with the future advent of JWST and perhaps the ngVLA, stronger constraints may be placed on the behavior of the galaxies in the epoch of initial galaxy formation.

  7. Influence of the turbulent motion on the chiral magnetic effect in the early universe

    NASA Astrophysics Data System (ADS)

    Dvornikov, Maxim; Semikoz, Victor B.

    2017-02-01

    We study the magnetohydrodynamics of relativistic plasmas accounting for the chiral magnetic effect (CME). To take into account the evolution of the plasma velocity, obeying the Navier-Stokes equation, we approximate it by the Lorentz force accompanied by the phenomenological drag time parameter. On the basis of this ansatz, we obtain the contributions of both the turbulence effects, resulting from the dynamo term, and the magnetic field instability, caused by the CME, to the evolution of the magnetic field governed by the modified Faraday equation. In this way, we explore the evolution of the magnetic field energy and the magnetic helicity density spectra in the early Universe plasma. We find that the right-left electron asymmetry is enhanced by the turbulent plasma motion in a strong seed magnetic field compared to the pure CME case studied earlier for the hot Universe plasma in the same broken phase.

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

    PubMed

    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.

  9. Warming early Mars with carbon dioxide clouds that scatter infrared radiation.

    PubMed

    Forget, F; Pierrehumbert, R T

    1997-11-14

    Geomorphic evidence that Mars was warm enough to support flowing water about 3.8 billion years ago presents a continuing enigma that cannot be explained by conventional greenhouse warming mechanisms. Model calculations show that the surface of early Mars could have been warmed through a scattering variant of the greenhouse effect, resulting from the ability of the carbon dioxide ice clouds to reflect the outgoing thermal radiation back to the surface. This process could also explain how Earth avoided an early irreversible glaciation and could extend the size of the habitable zone on extrasolar planets around stars.

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

    NASA Astrophysics Data System (ADS)

    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).

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-09-01

    Supermassive black holes existed less than a billion years after the Big Bang. Because black holes can grow at a maximum rate that depends on their current mass, it has been difficult to understand how such massive black holes could have formed so quickly. Hirano et al. developed simulations to show that streaming motions—velocity offsets between the gas and dark matter components—could have produced black holes with tens of thousands of solar masses in the early universe. That's big enough to grow into the supermassive black holes that we observe today.

  13. The early universe history from contraction-deformation of the Standard Model

    NASA Astrophysics Data System (ADS)

    Gromov, N. A.

    2017-03-01

    The elementary particles evolution in the early Universe from Plank time up to several milliseconds is presented. The developed theory is based on the high-temperature (high-energy) limit of the Standard Model which is generated by the contractions of its gauge groups. At the infinite temperature all particles lose masses. Only massless neutral -bosons, massless Z-quarks, neutrinos and photons are survived in this limit. The weak interactions become long-range and are mediated by neutral currents, quarks have only one color degree of freedom.

  14. Matter-antimatter asymmetry in the universe via string-inspired CPT violation at early eras

    NASA Astrophysics Data System (ADS)

    Mavromatos, Nick E.

    2018-01-01

    In four-space-time dimensional string/brane theory, obtained either through compactification of the extra spatial dimensions, or by appropriate restriction to brane worlds with three large spatial dimensions, the rich physics potential associated with the presence of non-trivial Kalb-Ramond (KR) axion-like fields has not been fully exploited so far. In this talk, I discuss a scenario whereby such fields produce spontaneous Lorentz- and CPT-violating cosmological backgrounds over which strings propagate, which in the early Universe can lead to Baryogenesis through Leptogenesis in models with heavy right-handed neutrinos.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Coherent active-sterile neutrino flavor transformation in the early universe.

    PubMed

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

    2006-10-06

    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) approximately 1 eV. This could result in better light element probes of (constraints on) these particles.

  17. Carbon Ion Radiotherapy At Gunma University: Currently Indicated Cancer And Estimation Of Need

    NASA Astrophysics Data System (ADS)

    Ohno, Tatsuya; Nakano, Takashi; Kanai, Tatsuaki; Yamada, Satoru

    2011-06-01

    Carbon ion radiotherapy for the first patient at Gunma University Heavy Ion Medical Center (GHMC) was initiated in March of 2010. The major specifications of the facility were determined based on the experience of clinical treatments at National Institute of Radiological Sciences (NIRS). The currently indicated sites of cancer treatment at GHMC are lung, prostate, head and neck, liver, rectum, bone and soft tissue. In order to evaluate the potential need for treatment in the region including Gunma prefecture and the adjacent 4 prefectures, an estimation model was constructed based on the Japanese cancer registration system, regular structure surveys by the Cancer Societies, and published articles on each cancer type. Carbon ion RT was potentially indicated for 8,085 patients and realistically for 1,527 patients, corresponding to 10% and 2% of the newly diagnosed cancer patients in the region. Prostate cancer (541 patients) followed by lung cancer (436 patients), and liver cancer (313 patients) were the most commonly diagnosed cancers.

  18. [Consumption of carbonated beverages with nonnutritive sweeteners in Latin American university students].

    PubMed

    Durán Agüero, Samuel; Record Cornwall, Jiniva; Encina Vega, Claudia; Salazar de Ariza, Julieta; Cordón Arrivillaga, Karla; Cereceda Bujaico, María del Pilar; Antezana Alzamora, Sonia; Espinoza Bernardo, Sissy

    2014-09-12

    Consumption of carbonated beverages with nonnutritive sweeteners (NNS) is increasingly common in order to maintain a healthy weight, but the effect of NNS on body weight is controversial. University students (n=1,229) of both sexes aged 18 to 26, of which 472 were from Chile, 300 of Panama, 253 from Guatemala and 204 of Peru. Each student was applied a frequency survey of weekly food consumption supported by photographs of beverages with NNS from each country to determine the intake of them. Also they underwent anthropometric measurements. 80% of these students consumed carbonated beverages with NNS, none of them exceeded the acceptable daily intake for sucralose, potassium acesulfame and aspartame. Increased consumption in both men and women was observed in chilean students (p. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  19. Stable carbon isotope fractionation in the search for life on early Mars

    NASA Technical Reports Server (NTRS)

    Rothschild, L. J.; Desmarais, D.

    1989-01-01

    The utility of measurements of C-13/C-12 ratios in organic vs inorganic deposits for searching for signs of life on early Mars is considered. It is suggested that three assumptions are necessary. First, if there was life on Mars, it caused the fractionation of carbon isotopes in analogy with past biological activity on earth. Second, the fractionation would be detectable. Third, if a fractionation would be observed, there exist no abiotic explanations for the observed fractionation pattern.

  20. Effects of early sea-floor processes on the taphonomy of temperate shelf skeletal carbonate deposits

    NASA Astrophysics Data System (ADS)

    Smith, Abigail M.; Nelson, Campbell S.

    2003-10-01

    Cool-water shelf carbonates differ from tropical carbonates in their sources, modes, and rates of deposition, geochemistry, and diagenesis. Inorganic precipitation, marine cementation, and sediment accumulation rates are absent or slow in cool waters, so that temperate carbonates remain longer at or near the sea bed. Early sea-floor processes, occurring between biogenic calcification and ultimate deposition, thus take on an important role, and there is the potential for considerable taphonomic loss of skeletal information into the fossilised record of cool-water carbonate deposits. The physical breakdown processes of dissociation, breakage, and abrasion are mediated mainly by hydraulic regime, and are always destructive. Impact damage reduces the size of grains, removes structure and therefore information, and ultimately may transform skeletal material into anonymous particles. Abrasion is highly selective amongst and within taxa, their skeletal form and structure strongly influencing resistance to mechanical breakdown. Dissolution and precipitation are the end-members of a two-way chemical equilibrium operating in sea water. In cool waters, inorganic precipitation is rare. There is conflicting opinion about the importance of diagenetic dissolution of carbonate skeletons on the temperate sea floor, but test maceration and early loss of aragonite in particular are reported. Dissolution may relate to undersaturated acidic pore waters generated locally by a combination of microbial metabolisation of organic matter, strong bioturbation, and oxidation of solid phase sulphides immediately beneath the sea floor in otherwise very slowly accumulating skeletal deposits. Laboratory experiments demonstrate that surface-to-volume ratio and skeletal mineralogy are both important in determining skeletal resistance to dissolution. Biological processes on the sea floor include encrustation and bioerosion. Encrustation, a constructive process, may be periodic or seasonal, and can be

  1. Early Results from the NASA Orbiting Carbon Observatory-2 (OCO-2)

    NASA Astrophysics Data System (ADS)

    Crisp, David; Eldering, Annmarie

    2015-04-01

    The Orbiting Carbon Observatory-2 (OCO-2) is NASA's first satellite designed to collect the measurements needed to estimate the column-averaged carbon dioxide (CO2) dry air mole fraction, XCO2, with the sensitivity, accuracy, and resolution needed to characterize the CO2 sources and sinks on regional scales over the globe. OCO-2 was successfully launched from Vandenberg Air Force Base in California on July 2, 2014 and joined the 705-km Afternoon Constellation (A-Train) on August 3, 2014. The three-channel imaging grating spectrometer was then cooled to its operating temperatures and a comprehensive series of characterization and calibration activities were initiated. Since early October 2014, the observatory has been routinely collecting almost 1 million soundings over the sunlit hemisphere each day. Early cloud screening results indicate that 15-30% of these measurements may be sufficiently cloud free to yield precise estimates of XCO2. Initial deliveries of calibrated, geo-located OCO-2 spectra to the NASA Goddard Earth Science Data and Information Services Center (GES DISC) began on December 30, 2014. Preliminary estimates of XCO2 retrieved from these data are currently being validated against observations from the Total Carbon Column Observing Network (TCCON) and other standards. Routine deliveries XCO2 and other products, including surface pressure and chlorophyll fluorescence, to the GES DISC are expected to begin before the end of March, 2015. This presentation will summarize the status of the OCO-2 mission and the coverage, resolution, and accuracy of its early results.

  2. Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra.

    PubMed

    Commane, Róisín; Lindaas, Jakob; Benmergui, Joshua; Luus, Kristina A; Chang, Rachel Y-W; Daube, Bruce C; Euskirchen, Eugénie S; Henderson, John M; Karion, Anna; Miller, John B; Miller, Scot M; Parazoo, Nicholas C; Randerson, James T; Sweeney, Colm; Tans, Pieter; Thoning, Kirk; Veraverbeke, Sander; Miller, Charles E; Wofsy, Steven C

    2017-05-23

    High-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO 2 ) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system. Here, we combine aircraft and tower observations of atmospheric CO 2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO 2 fluxes across Alaska during 2012-2014. We find that tundra ecosystems were a net source of CO 2 to the atmosphere annually, with especially high rates of respiration during early winter (October through December). Long-term records at Barrow, AK, suggest that CO 2 emission rates from North Slope tundra have increased during the October through December period by 73% ± 11% since 1975, and are correlated with rising summer temperatures. Together, these results imply increasing early winter respiration and net annual emission of CO 2 in Alaska, in response to climate warming. Our results provide evidence that the decadal-scale increase in the amplitude of the CO 2 seasonal cycle may be linked with increasing biogenic emissions in the Arctic, following the growing season. Early winter respiration was not well simulated by the Earth System Models used to forecast future carbon fluxes in recent climate assessments. Therefore, these assessments may underestimate the carbon release from Arctic soils in response to a warming climate.

  3. Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra

    NASA Astrophysics Data System (ADS)

    Commane, Róisín; Lindaas, Jakob; Benmergui, Joshua; Luus, Kristina A.; Chang, Rachel Y.-W.; Daube, Bruce C.; Euskirchen, Eugénie S.; Henderson, John M.; Karion, Anna; Miller, John B.; Miller, Scot M.; Parazoo, Nicholas C.; Randerson, James T.; Sweeney, Colm; Tans, Pieter; Thoning, Kirk; Veraverbeke, Sander; Miller, Charles E.; Wofsy, Steven C.

    2017-05-01

    High-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO2) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system. Here, we combine aircraft and tower observations of atmospheric CO2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO2 fluxes across Alaska during 2012-2014. We find that tundra ecosystems were a net source of CO2 to the atmosphere annually, with especially high rates of respiration during early winter (October through December). Long-term records at Barrow, AK, suggest that CO2 emission rates from North Slope tundra have increased during the October through December period by 73% ± 11% since 1975, and are correlated with rising summer temperatures. Together, these results imply increasing early winter respiration and net annual emission of CO2 in Alaska, in response to climate warming. Our results provide evidence that the decadal-scale increase in the amplitude of the CO2 seasonal cycle may be linked with increasing biogenic emissions in the Arctic, following the growing season. Early winter respiration was not well simulated by the Earth System Models used to forecast future carbon fluxes in recent climate assessments. Therefore, these assessments may underestimate the carbon release from Arctic soils in response to a warming climate.

  4. Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra

    PubMed Central

    Lindaas, Jakob; Benmergui, Joshua; Luus, Kristina A.; Chang, Rachel Y.-W.; Daube, Bruce C.; Euskirchen, Eugénie S.; Karion, Anna; Miller, John B.; Miller, Scot M.; Parazoo, Nicholas C.; Randerson, James T.; Sweeney, Colm; Thoning, Kirk; Veraverbeke, Sander; Miller, Charles E.; Wofsy, Steven C.

    2017-01-01

    High-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO2) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system. Here, we combine aircraft and tower observations of atmospheric CO2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO2 fluxes across Alaska during 2012–2014. We find that tundra ecosystems were a net source of CO2 to the atmosphere annually, with especially high rates of respiration during early winter (October through December). Long-term records at Barrow, AK, suggest that CO2 emission rates from North Slope tundra have increased during the October through December period by 73% ± 11% since 1975, and are correlated with rising summer temperatures. Together, these results imply increasing early winter respiration and net annual emission of CO2 in Alaska, in response to climate warming. Our results provide evidence that the decadal-scale increase in the amplitude of the CO2 seasonal cycle may be linked with increasing biogenic emissions in the Arctic, following the growing season. Early winter respiration was not well simulated by the Earth System Models used to forecast future carbon fluxes in recent climate assessments. Therefore, these assessments may underestimate the carbon release from Arctic soils in response to a warming climate. PMID:28484001

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    Markkanen, Tommi

    2018-01-01

    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'.

  7. Lyman-α Emission from an Infant Black Hole in the Early Universe

    SciTech Connect

    Wiggins, Brandon Kerry; Smidt, Joseph Michael; Johnson, Jarrett L.

    The COSMOS survey recently discovered an exotic young galaxy, COSMOS Redshift 7 (CR7), in the early universe (1 billion years after the Big Bang), which is devoid of evidence of elements heavier than hydrogen and helium. Whereas some believe this might be the first galaxy discovered with stars made only from these elements, others think CR7 may be powered by a newborn supermassive black hole. In this paper, we summarize for a general academic audience our efforts to model the creation of this galaxy through cosmological simulations. These state-of-the-art calculations include primordial chemistry and cooling and the interaction of x-raysmore » from the black hole with surrounding gas. We simulate the process of light escaping this object with Monte Carlo Lyman-α transfer and compare our calculations with observations of CR7. Our work demonstrates the viability of the black hole interpretation for this intriguing object in the early universe.« less

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

    PubMed

    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).

  9. Lyman-α Emission from an Infant Black Hole in the Early Universe

    DOE PAGES

    Wiggins, Brandon Kerry; Smidt, Joseph Michael; Johnson, Jarrett L.

    2016-01-01

    The COSMOS survey recently discovered an exotic young galaxy, COSMOS Redshift 7 (CR7), in the early universe (1 billion years after the Big Bang), which is devoid of evidence of elements heavier than hydrogen and helium. Whereas some believe this might be the first galaxy discovered with stars made only from these elements, others think CR7 may be powered by a newborn supermassive black hole. In this paper, we summarize for a general academic audience our efforts to model the creation of this galaxy through cosmological simulations. These state-of-the-art calculations include primordial chemistry and cooling and the interaction of x-raysmore » from the black hole with surrounding gas. We simulate the process of light escaping this object with Monte Carlo Lyman-α transfer and compare our calculations with observations of CR7. Our work demonstrates the viability of the black hole interpretation for this intriguing object in the early universe.« less

  10. A universal airborne LiDAR approach for tropical forest carbon mapping.

    PubMed

    Asner, Gregory P; Mascaro, Joseph; Muller-Landau, Helene C; Vieilledent, Ghislain; Vaudry, Romuald; Rasamoelina, Maminiaina; Hall, Jefferson S; van Breugel, Michiel

    2012-04-01

    Airborne light detection and ranging (LiDAR) is fast turning the corner from demonstration technology to a key tool for assessing carbon stocks in tropical forests. With its ability to penetrate tropical forest canopies and detect three-dimensional forest structure, LiDAR may prove to be a major component of international strategies to measure and account for carbon emissions from and uptake by tropical forests. To date, however, basic ecological information such as height-diameter allometry and stand-level wood density have not been mechanistically incorporated into methods for mapping forest carbon at regional and global scales. A better incorporation of these structural patterns in forests may reduce the considerable time needed to calibrate airborne data with ground-based forest inventory plots, which presently necessitate exhaustive measurements of tree diameters and heights, as well as tree identifications for wood density estimation. Here, we develop a new approach that can facilitate rapid LiDAR calibration with minimal field data. Throughout four tropical regions (Panama, Peru, Madagascar, and Hawaii), we were able to predict aboveground carbon density estimated in field inventory plots using a single universal LiDAR model (r ( 2 ) = 0.80, RMSE = 27.6 Mg C ha(-1)). This model is comparable in predictive power to locally calibrated models, but relies on limited inputs of basal area and wood density information for a given region, rather than on traditional plot inventories. With this approach, we propose to radically decrease the time required to calibrate airborne LiDAR data and thus increase the output of high-resolution carbon maps, supporting tropical forest conservation and climate mitigation policy.

  11. Footwall progradation in syn-rift carbonate platform-slope systems (Early Jurassic, Northern Apennines, Italy)

    NASA Astrophysics Data System (ADS)

    Fabbi, Simone; Santantonio, Massimo

    2012-12-01

    The so-called Umbria-Marche Domain of Northern Apennines represents a vast depositional system, also stretching across the Adriatic Sea subsurface, that was characterized by dominantly pelagic sedimentation through most of its Jurassic to Oligocene/Early Miocene history. The pelagic succession is underlain by Hettangian shallow-water carbonates (Calcare Massiccio Fm.), constituting a regional carbonate platform that was subjected to tectonic extension due to rifting of the Adria/African Plate in the earliest Jurassic. While tectonic subsidence of the hangingwalls drove the drowning of the platform around the Hettangian/Sinemurian boundary, the production of benthic carbonate on footwall blocks continued parallel to faulting, through a sequence of facies that was abruptly terminated by drowning and development of condensed pelagites in the early Pliensbachian. By then rifting had ceased, so that the Pliensbachian to Early Cretaceous hangingwall deposits represent a post-rift basin-fill succession onlapping the tectonically-generated escarpment margins of the highs. During the early phases of syndepositional faulting, the carbonate factories of footwall blocks were still temporarily able to fill part of the accommodation space produced by the normal faults by prograding into the incipient basins. In this paper we describe for the first time a relatively low-angle (< 10°) clinoform bed package documenting such an ephemeral phase of lateral growth of a carbonate factory. The clinoforms are sigmoidal, and form low-relief (maximum 5-7 m) bodies representing a shallow-water slope that was productive due to development of a Lithocodium-dominated factory. Continued faulting and hangingwall subsidence then decoupled the slope from the platform top, halting the growth of clinoforms and causing the platform margin to switch from accretionary to bypass mode as the pre-rift substrate became exposed along a submarine fault escarpment. The downfaulted clinoform slope was then

  12. Diet and mobility in Early Medieval Bavaria: a study of carbon and nitrogen stable isotopes.

    PubMed

    Hakenbeck, Susanne; McManus, Ellen; Geisler, Hans; Grupe, Gisela; O'Connell, Tamsin

    2010-10-01

    This study investigates patterns of mobility in Early Medieval Bavaria through a combined study of diet and associated burial practice. Carbon and nitrogen isotope ratios were analyzed in human bone samples from the Late Roman cemetery of Klettham and from the Early Medieval cemeteries of Altenerding and Straubing-Bajuwarenstrasse. For dietary comparison, samples of faunal bone from one Late Roman and three Early Medieval settlement sites were also analyzed. The results indicate that the average diet was in keeping with a landlocked environment and fairly limited availability of freshwater or marine resources. The diet appears not to have changed significantly from the Late Roman to the Early Medieval period. However, in the population of Altenerding, there were significant differences in the diet of men and women, supporting a hypothesis of greater mobility among women. Furthermore, the isotopic evidence from dietary outliers is supported by "foreign" grave goods and practices, such as artificial skull modification. These results reveal the potential of carbon and nitrogen isotope analysis for questions regarding migration and mobility. © 2010 Wiley-Liss, Inc.

  13. From Universalism to Selectivity? The Background, Discourses and Ideas of Recent Early Childhood Education and Care Reforms in Finland

    ERIC Educational Resources Information Center

    Lundkvist, Marina; Nyby, Josefine; Autto, Janne; Nygård, Mikael

    2017-01-01

    Universal public childcare for children under seven has been central in Finland since the mid-1990s, capacitating both gender equality and children's human capital and wellbeing. In 2015, as a further step in the development of this system, early learning and childhood pedagogy was strengthened through the early childhood education and care (ECEC)…

  14. Early Childhood Pre-Service Teachers' Concerns and Solutions to Overcome Them (the Case of Pamukkale University)

    ERIC Educational Resources Information Center

    Cevher-Kalburan, Nilgün

    2014-01-01

    The purpose of this qualitative study is to determine early childhood pre-service teachers' concerns and solutions. One hundred early childhood pre-service teachers who were enrolled at Pamukkale University, Turkey, answered two open-ended questions by e-mail. In addition, six of these participants were interviewed for developing a deeper…

  15. From simple to complex prebiotic chemistry in a carbon-rich universe

    NASA Astrophysics Data System (ADS)

    Lage, C.; Janot-Pacheco, E.; Domiciano de Souza, A.; Suárez, O.; Bendjoya, P.; Gadotti, D. A.

    2012-09-01

    It is well known that the main components of important biomolecules are quite common not only in the Solar System, but also in other planetary systems and in the Galactic ISM. The ubiquitous presence of C in the Universe and the unique carbon chemical properties and carbon bonding thermodynamics supports the spontaneous self-replication of monomers into larger polymers, yielding the formation of large molecules. The detection of an ever increasing number of organic molecules in the interstellar medium (ISM) by radio-telescopes and chemical analysis of meteorites boosted astrochemical theories on radiation-induced chemistry, supported by laboratory experiments. In this scenario of exogenous origin of carbon compounds, polyaromatic hydrocarbons (PAHs) may represent a resilient way of accumulating carbon as a robust cosmic reservoir. Consisting of a family of compounds with fused aromatic rings, the abundances of its larger members (50-100 carbon atoms) were estimated to be on top scores just after H2 and CO. PAHs have been detected in the ISM, in star-forming regions, ~14% of low-mass premainsequence stars, and, remarkably, in some 54% of intermediate mass stars. They have also been detected by SPITZER in distant galaxies up to z = 3. PAHs were promptly photolysed into a family of radicals if exposed to UV and oxygen-bearing molecules in laboratory. The presence of oxygenbearing molecules was shown in the laboratory to bring aromatic rings into an unstable chemistry leading to the production of e.g. alcohols, ketones and ether radicals. It has already been observed that carbon-and oxygen-rich stellar envelopes give rise to richer carbon chemistry. It appears very tempting to think that key prebiotic fragments should appear along planetary formation as C-O reaction byproducts such as methanol (CH3OH), formaldehyde (H2CO) and also simpler hydrocarbons as methyl acetylene (CH3CCH). Under an Astrobiology perspective it is plausible to map PAHs and oxygen compounds

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

    PubMed Central

    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

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

    PubMed

    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.

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

    PubMed

    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.

  19. Building the Next Generation of Earth Scientists: the Deep Carbon Observatory Early Career Scientist Workshops

    NASA Astrophysics Data System (ADS)

    Pratt, K.; Fellowes, J.; Giovannelli, D.; Stagno, V.

    2016-12-01

    Building a network of collaborators and colleagues is a key professional development activity for early career scientists (ECS) dealing with a challenging job market. At large conferences, young scientists often focus on interacting with senior researchers, competing for a small number of positions in leading laboratories. However, building a strong, international network amongst their peers in related disciplines is often as valuable in the long run. The Deep Carbon Observatory (DCO) began funding a series of workshops in 2014 designed to connect early career researchers within its extensive network of multidisciplinary scientists. The workshops, by design, are by and for early career scientists, thus removing any element of competition and focusing on peer-to-peer networking, collaboration, and creativity. The successful workshops, organized by committees of early career deep carbon scientists, have nucleated a lively community of like-minded individuals from around the world. Indeed, the organizers themselves often benefit greatly from the leadership experience of pulling together an international workshop on budget and on deadline. We have found that a combination of presentations from all participants in classroom sessions, professional development training such as communication and data management, and field-based relationship building and networking is a recipe for success. Small groups within the DCO ECS network have formed; publishing papers together, forging new research directions, and planning novel and ambitious field campaigns. Many DCO ECS also have come together to convene sessions at major international conferences, including the AGU Fall Meeting. Most of all, there is a broad sense of camaraderie and accessibility within the DCO ECS Community, providing the foundation for a career in the new, international, and interdisciplinary field of deep carbon science.

  20. A 2009 Mobile Source Carbon Dioxide Emissions Inventory for the University of Central Florida.

    PubMed

    Clifford, Johanna M; Cooper, C David

    2012-09-01

    A mobile source carbon dioxide (CO2) emissions inventory for the University of Central Florida (UCF) has been completed. Fora large urban university, more than 50% of the CO2 emissions can come from mobile sources, and the vast majority of mobile source emissions come from on-road sources: personal vehicles and campus shuttles carrying students, faculty, staff and administrators to and from the university as well as on university business trips. In addition to emissions from on-road vehicles, emissions from airplane-based business travel are significant, along with emissions from nonroad equipment such as lawnmowers, leaf blowers, and small maintenance vehicles utilized on campus. UCF has recently become one of the largest universities in the nation (with over 58,000 students enrolled in the fall 2011 semester) and emits a substantial amount of CO2 in the Central Florida area. For this inventory, students, faculty, staff and administrators were first surveyed to determine their commuting distances and frequencies. Information was also gathered on vehicle type and age distribution of the personal vehicles of students, faculty, administrators, and staff as well as their bus, car-pool, and alternate transportation usage. The latest US. Environmental Protection Agency (EPA)-approved mobile source emissions model, Motor Vehicle Emissions Simulator (MOVES2010a), was used to calculate the emissions from on-road vehicles, and UCF fleet gasoline consumption records were used to calculate the emissions from nonroad equipment and from on-campus UCF fleet vehicles. The results of this UCF mobile source emissions inventory were compared with those for another large U.S. university. With the growing awareness of global climate change, a number of colleges/universities and other organizations are completing greenhouse gas emission inventories. Assumptions often are made in order to calculate mobile source emissions, but without field data or valid reasoning, the accuracy of those

  1. Effectiveness of potassium carbonate sesquihydrate to increase dietary cation-anion difference in early lactation cows.

    PubMed

    Harrison, J; White, R; Kincaid, R; Block, E; Jenkins, T; St-Pierre, N

    2012-07-01

    The effect of additional dietary potassium in early lactation dairy cows was evaluated with the addition of potassium carbonate sesquihydrate, which increased dietary K from 1.3 to 2.1% of dry matter (DM) from wk 3 to 12 of lactation. Cows fed potassium carbonate sesquihydrate in the form of DCAD Plus (Church & Dwight Co. Inc., Princeton, NJ) had increased DM intake, milk fat percentage and yield, energy-corrected milk, and efficiency of milk production per unit of DM intake. Milk fat of cows fed higher dietary K had a lower concentration of trans fatty acids, suggesting a role for potassium carbonate sesquihydrate in the rumen in the biohydrogenation processes converting linoleic to stearic acid. Cows fed the diet with 2.1% K had greater apparent balance of K, and no effects were noted on the concentration of blood Mg or amount of fecal Mg. The data support the feeding of greater amounts of K in the early lactation cow. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  2. New insights into the early stages of silica-controlled barium carbonate crystallisation

    NASA Astrophysics Data System (ADS)

    Eiblmeier, Josef; Schürmann, Ulrich; Kienle, Lorenz; Gebauer, Denis; Kunz, Werner; Kellermeier, Matthias

    2014-11-01

    Recent work has demonstrated that the dynamic interplay between silica and carbonate during co-precipitation can result in the self-assembly of unusual, highly complex crystal architectures with morphologies and textures resembling those typically displayed by biogenic minerals. These so-called biomorphs were shown to be composed of uniform elongated carbonate nanoparticles that are arranged according to a specific order over mesoscopic scales. In the present study, we have investigated the circumstances leading to the continuous formation and stabilisation of such well-defined nanometric building units in these inorganic systems. For this purpose, in situ potentiometric titration measurements were carried out in order to monitor and quantify the influence of silica on both the nucleation and early growth stages of barium carbonate crystallisation in alkaline media at constant pH. Complementarily, the nature and composition of particles occurring at different times in samples under various conditions were characterised ex situ by means of high-resolution electron microscopy and elemental analysis. The collected data clearly evidence that added silica affects carbonate crystallisation from the very beginning (i.e. already prior to, during, and shortly after nucleation), eventually arresting growth on the nanoscale by cementation of BaCO3 particles within a siliceous matrix. Our findings thus shed light on the fundamental processes driving bottom-up self-organisation in silica-carbonate materials and, for the first time, provide direct experimental proof that silicate species are responsible for the miniaturisation of carbonate crystals during growth of biomorphs, hence confirming previously discussed theoretical models for their formation mechanism.Recent work has demonstrated that the dynamic interplay between silica and carbonate during co-precipitation can result in the self-assembly of unusual, highly complex crystal architectures with morphologies and textures

  3. Differences in carbon source usage by dental plaque in children with and without early childhood caries

    PubMed Central

    Zhao, Yan; Zhong, Wen-Jie; Xun, Zhe; Zhang, Qian; Song, Ye-Qing; Liu, Yun-Song; Chen, Feng

    2017-01-01

    Early childhood caries (ECC) is a considerable pediatric and public health problem worldwide. Preceding studies have focused primarily on bacterial diversity at the taxonomic level. Although these studies have provided significant information regarding the connection between dental caries and oral microbiomes, further comprehension of this microbial community’s ecological relevance is limited. This study identified the carbon source metabolic differences in dental plaque between children with and without ECC. We compared the microbial community functional diversity in 18 caries-free subjects with 18 severe ECC patients based on sole carbon source usage using a Biolog assay. The anaerobic microbial community in the ECC patients displayed greater metabolic activity than that of the control group. Specific carbon source metabolism differed significantly between the two groups. Subjects from the two groups were well distinguished by cluster and principal component analyses based on discriminative carbon sources. Our results implied that the microbial functional diversity between the ECC patients and healthy subjects differed significantly. In addition, the Biolog assay furthered our understanding of oral microbiomes as a composite of functional abilities, thus enabling us to identify the ecologically relevant functional differences among oral microbial communities.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Geochemical characteristics and early diagenesis of recent carbonate mound sediments in the Gulf of Cadiz

    NASA Astrophysics Data System (ADS)

    Hamaekers, Helen; Foubert, Anneleen; Wienberg, Claudia; Hebbeln, Dierk; Swennen, Rudy

    2010-05-01

    Cold-water coral carbonate mounds occur in patches along the continental margin of the North Atlantic Ocean, from northern Norway down to Mauretania. Recent research has been focused on carbonate mounds in the Gulf of Cadiz, especially along the Moroccan margin. The Pen Duick, the Renard and the Vernadsky carbonate mound provinces in the Gulf of Cádiz are only some of the mound provinces which have been the subject of several recent research projects (Foubert et al., 2008; Wienberg et al., 2009). No living scleractinians could be found on top of those carbonate mounds. During cruise 64PE284 of RV Pelagia, gravity cores have been taken through carbonate mounds in the Carbonate Mound Provinces (CMP) SE of Yuma mud volcano and N of Meknes mud volcano. These cores have been analysed by several methods such as Magnetic Susceptibility (MS), X-Ray Fluorescence (XRF), Inductive Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and X-Ray Diffraction (XRD) to determine the geochemical characteristics of carbonate mounds, which can be used to quantify the effects of early diagenetic processes which may have altered the palaeo-environmental characteristics of the carbonate mounds. Dating has been done with 14C and U/Th methods pointing to mound growth phases being restricted to glacial periods. XRF and ICP-OES measurements give both qualitative and quantitative data of the chemical composition of the core. The main elements that have been analysed are Ca, Si, Fe, Sr, Al, K, Mg, Ti. According to the trend they follow, they can be devided in two groups, representative for the two encountered fraction types. These two fraction types (biogenic carbonate-rich fraction and terrigenous silicate-rich fraction) can be coupled to interglacial/glacial palaeo-environmental conditions. XRD measurements give an overview of the mineralogical composition of the cores. Thin sections, analysed by cathodeluminescence and classical optical petrography, and micro-CT scans are used to

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Bar Evolution and Bar Properties from Disc Galaxies in the Early Universe

    NASA Astrophysics Data System (ADS)

    Hutchinson-Smith, Tenley; Simmons, Brooke

    2017-01-01

    Bars in disc galaxies indicate a large collection of stars in a specific configuration of orbits that give the galaxy center a rectangular looking feature. Astronomers have discovered that these bars affect the distribution of matter in galaxies, and are also related to galaxy stellar mass and star formation history. Little is known about the specifics of how bars evolve and drive the evolution of their host galaxies because only a handful of bars have been studied in detail so far. I have examined a sample of 8,221 barred galaxies from the early universe to identify and examine correlations with galaxy properties. The data comes from Galaxy Zoo, an online citizen science project that allows anyone to classify and measure detailed properties of galaxies. I present results including the fraction of galaxies in the sample that have bars, and the variation of galaxy properties with bar length, including galaxy color and stellar mass. I also compare these results to barred galaxies in the local universe. I will discuss the implications of these results in the context of galaxy evolution overall, including the effect of dark matter on bars and galaxy evolution.

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

    NASA Astrophysics Data System (ADS)

    Horvat, Raul; Trampetic, Josip; You, Jiangyang

    2017-09-01

    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.

  14. The effects of early diagenesis on the chemical and stable carbon isotopic composition of wood

    USGS Publications Warehouse

    Spiker, E. C.; Hatcher, P.G.

    1987-01-01

    Studies of modern and ancient buried wood show that there is a linear correlation between carbohydrate content and the stable carbon isotope composition as carbohydrates are preferentially degraded during early diagenesis. As the carbohydrate content decreases, the ??13C value of the degraded wood decreases 1 to 2 per mil, approaching the value of the residual lignin. These results indicate that carbohydrate degradation products are lost and not incorporated into the aromatic structure as lignin is selectively preserved during early diagenesis of wood. These results also indicate that attempts to quantify terrestrial inputs to modern sedimentary organic matter based on ??13C values should consider the possibility of a 1 to 2 per mil decrease in the ??13C value of degraded wood. ?? 1987.

  15. Early Implementation of Large Scale Carbon Dioxide Removal Projects through the Cement Industry

    NASA Astrophysics Data System (ADS)

    Zeman, F. S.

    2014-12-01

    The development of large-scale carbon dioxide reduction projects requires high purity CO2and a reactive cation source. A project seeking to provide both of these requirements will likely face cost barriers with current carbon prices. The cement industry is a suitable early implementation site for such projects by virtue of the properties of its exhaust gases and those of waste concrete. Cement plants are the second largest source of industrial CO2 emissions, globally. It is also the second largest commodity after water, has no ready substitute and is literally the foundation of society. Finally, half of the CO2 emissions originate from process reactions rather than fossil fuel combustion resulting in higher flue gas CO2concentrations. These properties, with the co-benefits of oxygen combustion, create a favorable environment for spatially suitable projects. Oxygen combustion involves substituting produced oxygen for air in a combustion reaction. The absence of gaseous N2 necessitates the recirculation of exhaust gases to maintain kiln temperatures, which increase the CO2 concentrations from 28% to 80% or more. Gas exit temperatures are also elevated (>300oC) and can reach higher temperatures if the multi stage pre-heater towers, that recover heat, are re-designed in light of FGR. A ready source of cations can be found in waste concrete, a by-product of construction and demolition activities. These wastes can be processed to remove cations and then reacted with atmospheric CO2 to produce carbonate minerals. While not carbon negative, they represent a demonstration opportunity for binding atmospheric CO2while producing a saleable product (precipitated calcium carbonate). This paper will present experimental results on PCC production from waste concrete along with modeling results for oxygen combustion at cement facilities. The results will be presented with a view to mineral sequestration process design and implementation.

  16. Multidisciplinary Optimization of Oral Chemotherapy Delivery at the University of Wisconsin Carbone Cancer Center.

    PubMed

    Mulkerin, Daniel L; Bergsbaken, Jason J; Fischer, Jessica A; Mulkerin, Mary J; Bohler, Aaron M; Mably, Mary S

    2016-10-01

    Use of oral chemotherapy is expanding and offers advantages while posing unique safety challenges. ASCO and the Oncology Nursing Society jointly published safety standards for administering chemotherapy that offer a framework for improving oral chemotherapy practice at the University of Wisconsin Carbone Cancer Center. With the goal of improving safety, quality, and uniformity within our oral chemotherapy practice, we conducted a gap analysis comparing our practice against ASCO/Oncology Nursing Society guidelines. Areas for improvement were addressed by multidisciplinary workgroups that focused on education, workflows, and information technology. Recommendations and process changes included defining chemotherapy, standardizing patient and caregiver education, mandating the use of comprehensive electronic order sets, and standardizing documentation for dose modification. Revised processes allow pharmacists to review all orders for oral chemotherapy, and they support monitoring adherence and toxicity by using a library of scripted materials. Between August 2015 and January 2016, revised processes were implemented across the University of Wisconsin Carbone Cancer Center clinics. The following are key performance indicators: 92.5% of oral chemotherapy orders (n = 1,216) were initiated within comprehensive electronic order sets (N = 1,315), 89.2% compliance with informed consent was achieved, 14.7% of orders (n = 193) required an average of 4.4 minutes review time by the pharmacist, and 100% compliance with first-cycle monitoring of adherence and toxicity was achieved. We closed significant gaps between institutional practice and published standards for our oral chemotherapy practice and experienced steady improvement and sustainable performance in key metrics. We created an electronic definition of oral chemotherapies that allowed us to leverage our electronic health records. We believe our tools are broadly applicable.

  17. Multidisciplinary Optimization of Oral Chemotherapy Delivery at the University of Wisconsin Carbone Cancer Center

    PubMed Central

    Bergsbaken, Jason J.; Fischer, Jessica A.; Mulkerin, Mary J.; Bohler, Aaron M.; Mably, Mary S.

    2016-01-01

    Purpose: Use of oral chemotherapy is expanding and offers advantages while posing unique safety challenges. ASCO and the Oncology Nursing Society jointly published safety standards for administering chemotherapy that offer a framework for improving oral chemotherapy practice at the University of Wisconsin Carbone Cancer Center. Methods: With the goal of improving safety, quality, and uniformity within our oral chemotherapy practice, we conducted a gap analysis comparing our practice against ASCO/Oncology Nursing Society guidelines. Areas for improvement were addressed by multidisciplinary workgroups that focused on education, workflows, and information technology. Recommendations and process changes included defining chemotherapy, standardizing patient and caregiver education, mandating the use of comprehensive electronic order sets, and standardizing documentation for dose modification. Revised processes allow pharmacists to review all orders for oral chemotherapy, and they support monitoring adherence and toxicity by using a library of scripted materials. Results: Between August 2015 and January 2016, revised processes were implemented across the University of Wisconsin Carbone Cancer Center clinics. The following are key performance indicators: 92.5% of oral chemotherapy orders (n = 1,216) were initiated within comprehensive electronic order sets (N = 1,315), 89.2% compliance with informed consent was achieved, 14.7% of orders (n = 193) required an average of 4.4 minutes review time by the pharmacist, and 100% compliance with first-cycle monitoring of adherence and toxicity was achieved. Conclusion: We closed significant gaps between institutional practice and published standards for our oral chemotherapy practice and experienced steady improvement and sustainable performance in key metrics. We created an electronic definition of oral chemotherapies that allowed us to leverage our electronic health records. We believe our tools are broadly applicable. PMID

  18. 0 - π Quantum transition in a carbon nanotube Josephson junction: Universal phase dependence and orbital degeneracy

    NASA Astrophysics Data System (ADS)

    Delagrange, R.; Weil, R.; Kasumov, A.; Ferrier, M.; Bouchiat, H.; Deblock, R.

    2018-05-01

    In a quantum dot hybrid superconducting junction, the behavior of the supercurrent is dominated by Coulomb blockade physics, which determines the magnetic state of the dot. In particular, in a single level quantum dot singly occupied, the sign of the supercurrent can be reversed, giving rise to a π-junction. This 0 - π transition, corresponding to a singlet-doublet transition, is then driven by the gate voltage or by the superconducting phase in the case of strong competition between the superconducting proximity effect and Kondo correlations. In a two-level quantum dot, such as a clean carbon nanotube, 0- π transitions exist as well but, because more cotunneling processes are allowed, are not necessarily associated to a magnetic state transition of the dot. In this proceeding, after a review of 0- π transitions in Josephson junctions, we present measurements of current-phase relation in a clean carbon nanotube quantum dot, in the single and two-level regimes. In the single level regime, close to orbital degeneracy and in a regime of strong competition between local electronic correlations and superconducting proximity effect, we find that the phase diagram of the phase-dependent transition is a universal characteristic of a discontinuous level-crossing quantum transition at zero temperature. In the case where the two levels are involved, the nanotube Josephson current exhibits a continuous 0 - π transition, independent of the superconducting phase, revealing a different physical mechanism of the transition.

  19. Carbon Ion Radiotherapy at the Gunma University Heavy Ion Medical Center: New Facility Set-up

    PubMed Central

    Ohno, Tatsuya; Kanai, Tatsuaki; Yamada, Satoru; Yusa, Ken; Tashiro, Mutsumi; Shimada, Hirofumi; Torikai, Kota; Yoshida, Yukari; Kitada, Yoko; Katoh, Hiroyuki; Ishii, Takayoshi; Nakano, Takashi

    2011-01-01

    Carbon ion radiotherapy (C-ion RT) offers superior dose conformity in the treatment of deep-seated tumors compared with conventional X-ray therapy. In addition, carbon ion beams have a higher relative biological effectiveness compared with protons or X-ray beams. C-ion RT for the first patient at Gunma University Heavy Ion Medical Center (GHMC) was initiated in March of 2010. The major specifications of the facility were determined based on the experience of clinical treatments at the National Institute of Radiological Sciences (NIRS), with the size and cost being reduced to one-third of those at NIRS. The currently indicated sites of cancer treatment at GHMC are lung, prostate, head and neck, liver, rectum, bone and soft tissue. Between March 2010 and July 2011, a total of 177 patients were treated at GHMC although a total of 100 patients was the design specification during the period in considering the optimal machine performance. In the present article, we introduce the facility set-up of GHMC, including the facility design, treatment planning systems, and clinical preparations. PMID:24213124

  20. Carbon Ion Radiotherapy at the Gunma University Heavy Ion Medical Center: New Facility Set-up.

    PubMed

    Ohno, Tatsuya; Kanai, Tatsuaki; Yamada, Satoru; Yusa, Ken; Tashiro, Mutsumi; Shimada, Hirofumi; Torikai, Kota; Yoshida, Yukari; Kitada, Yoko; Katoh, Hiroyuki; Ishii, Takayoshi; Nakano, Takashi

    2011-10-26

    Carbon ion radiotherapy (C-ion RT) offers superior dose conformity in the treatment of deep-seated tumors compared with conventional X-ray therapy. In addition, carbon ion beams have a higher relative biological effectiveness compared with protons or X-ray beams. C-ion RT for the first patient at Gunma University Heavy Ion Medical Center (GHMC) was initiated in March of 2010. The major specifications of the facility were determined based on the experience of clinical treatments at the National Institute of Radiological Sciences (NIRS), with the size and cost being reduced to one-third of those at NIRS. The currently indicated sites of cancer treatment at GHMC are lung, prostate, head and neck, liver, rectum, bone and soft tissue. Between March 2010 and July 2011, a total of 177 patients were treated at GHMC although a total of 100 patients was the design specification during the period in considering the optimal machine performance. In the present article, we introduce the facility set-up of GHMC, including the facility design, treatment planning systems, and clinical preparations.

  1. Modeling carbon-nutrient interactions during the early recovery of tundra after fire.

    PubMed

    Jiang, Yueyang; Rastetter, Edward B; Rocha, Adrian V; Pearce, Andrea R; Kwiatkowski, Bonnie L; Shaver, Gaius R

    2015-09-01

    Fire frequency has dramatically increased in the tundra of northern Alaska, USA, which has major implications for the carbon budget of the region and the functioning of these ecosystems, which support important wildlife species. We investigated the postfire succession of plant and soil carbon (C), nitrogen (N), and phosphorus (P) fluxes and stocks along a burn severity gradient in the 2007 Anaktuvuk River fire scar in northern Alaska. Modeling results indicated that the early regrowth of postfire tundra vegetation was limited primarily by its canopy photosynthetic potential, rather than nutrient availability, because of the initially low leaf area and relatively high inorganic N and P concentrations in soil. Our simulations indicated that the postfire recovery of tundra vegetation was sustained predominantly by the uptake of residual inorganic N (i.e., in the remaining ash), and the redistribution of N and P from soil organic matter to vegetation. Although residual nutrients in ash were higher in the severe burn than the moderate burn, the moderate burn recovered faster because of the higher remaining biomass and consequent photosynthetic potential. Residual nutrients in ash allowed both burn sites to recover and exceed the unburned site in both aboveground biomass and production five years after the fire. The investigation of interactions among postfire C, N, and P cycles has contributed to a mechanistic understanding of the response of tundra ecosystems to fire disturbance. Our study provided insight on how the trajectory of recovery of tundra from wildfire is regulated during early succession.

  2. In search of early life: Carbonate veins in Archean metamorphic rocks as potential hosts of biomarkers

    NASA Astrophysics Data System (ADS)

    Peters, Carl A.; Piazolo, Sandra; Webb, Gregory E.; Dutkiewicz, Adriana; George, Simon C.

    2016-11-01

    The detection of early life signatures using hydrocarbon biomarkers in Precambrian rocks struggles with contamination issues, unspecific biomarkers and the lack of suitable sedimentary rocks due to extensive thermal overprints. Importantly, host rocks must not have been exposed to temperatures above 250 °C as at these temperatures biomarkers are destroyed. Here we show that Archean sedimentary rocks from the Jeerinah Formation (2.63 billion yrs) and Carawine Dolomite (2.55 billion yrs) of the Pilbara Craton (Western Australia) drilled by the Agouron Institute in 2012, which previously were suggested to be suitable for biomarker studies, were metamorphosed to the greenschist facies. This is higher than previously reported. Both the mineral assemblages (carbonate, quartz, Fe-chlorite, muscovite, microcline, rutile, and pyrite with absence of illite) and chlorite geothermometry suggest that the rocks were exposed to temperatures higher than 300 °C and probably ∼400 °C, consistent with greenschist-facies metamorphism. This facies leads to the destruction of any biomarkers and explains why the extraction of hydrocarbon biomarkers from pristine drill cores has not been successful. However, we show that the rocks are cut by younger formation-specific carbonate veins containing primary oil-bearing fluid inclusions and solid bitumens. Type 1 veins in the Carawine Dolomite consist of dolomite, quartz and solid bitumen, whereas type 2 veins in the Jeerinah Formation consist of calcite. Within the veins fluid inclusion homogenisation temperatures and calcite twinning geothermometry indicate maximum temperatures of ∼200 °C for type 1 veins and ∼180 °C for type 2 veins. Type 1 veins have typical isotopic values for reprecipitated Archean sea-water carbonates, with δ13CVPDB ranging from - 3 ‰ to 0‰ and δ18OVPDB ranging from - 13 ‰ to - 7 ‰, while type 2 veins have isotopic values that are similar to hydrothermal carbonates, with δ13CVPDB ranging from - 18

  3. Facies interfingering and synsedimentary tectonics on late Ladinian-early Carnian carbonate platforms (Dolomites, Italy)

    NASA Astrophysics Data System (ADS)

    Keim, Lorenz; Brandner, Rainer

    2001-11-01

    A stratigraphic model for carbonate platform evolution in the Dolomites during the late Ladinian-early Carnian is presented. New light on pre-Raibl growth of individual carbonate platforms of the western Dolomites was shed by biostratigraphic data combined with a revised lithostratigraphy. At the Schlern, Langkofel and Sella, the carbonate factory (Upper Schlern Dolomite) remained productive into the lowermost Carnian (Cordevolian = Aon Zone), and caused a levelling-out of the former steep platform-to-basin relief. In the eastern Dolomites, platforms were producing till basal Julian 2 (Austriacum Zone). At the Sella and Langkofel, the sedimentation pattern after deposition of the Upper Schlern Dolomite was strongly influenced by synsedimentary tectonics. A first phase of extensional tectonics led to local fissures, block-tilting, graben structures and breccia deposits. Composition and fabric of the reworked clasts argue for local-source sediments and short transport distances. The extensional structures are sealed by sediments of Lower Carnian age. Two facies belts (Schlernplateau beds and Dürrenstein Dolomite), which interfinger at the western side of the Sella, reflect the shallow marine environment with terrigenous-volcanoclastic input in the western Dolomites. A second generation of breccias at the Sella documents local fracturing of the Dürrenstein and Upper Schlern Dolomite. Depositional environments across the western and eastern Dolomites were largely dependent on differential subsidence. The sediments of early Carnian age on top of the Schlern platform are a few metres thick only, whereas, in the eastern Dolomite, up to 400-m-thick carbonate sediments ('Richthofen reef' and Settsass platform) were deposited. The most incomplete stratigraphic record is present at the Mendel platform in the west, where Ladinian volcanics are unconformably overlain by late Carnian 'Raibl beds'. The increase in sediment thickness towards the eastern Dolomites becomes partly

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

    NASA Astrophysics Data System (ADS)

    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

  5. Pink salmon ( Oncorhynchus gorbuscha) marine survival rates reflect early marine carbon source dependency

    NASA Astrophysics Data System (ADS)

    Kline, Thomas C., Jr.; Boldt, Jennifer L.; Farley, Edward V., Jr.; Haldorson, Lewis J.; Helle, John H.

    2008-05-01

    Marine survival rate (the number of adult salmon returning divided by the number of salmon fry released) of pink salmon runs propagated by Prince William Sound, Alaska (PWS) salmon hatcheries is highly variable resulting in large year-to-year run size variation, which ranged from ∼20 to ∼50 million during 1998-2004. Marine survival rate was hypothesized to be determined during their early marine life stage, a time period corresponding to the first growing season after entering the marine environment while they are still in coastal waters. Based on the predictable relationships of 13C/ 12C ratios in food webs and the existence of regional 13C/ 12C gradients in organic carbon, 13C/ 12C ratios of early marine pink salmon were measured to test whether marine survival rate was related to food web processes. Year-to-year variation in marine survival rate was inversely correlated to 13C/ 12C ratios of early marine pink salmon, but with differences among hatcheries. The weakest relationship was for pink salmon from the hatchery without historic co-variation of marine survival rate with other PWS hatcheries or wild stocks. Year-to-year variation in 13C/ 12C ratio of early marine stage pink salmon in combination with regional spatial gradients of 13C/ 12C ratio measured in zooplankton suggested that marine survival was driven by carbon subsidies of oceanic origin (i.e., oceanic zooplankton). The 2001 pink salmon cohort had 13C/ 12C ratios that were very similar to those found for PWS carbon, i.e., when oceanic subsidies were inferred to be nil, and had the lowest marine survival rate (2.6%). Conversely, the 2002 cohort had the highest marine survival (9.7%) and the lowest mean 13C/ 12C ratio. These isotope patterns are consistent with hypotheses that oceanic zooplankton subsidies benefit salmon as food subsidies, or as alternate prey for salmon predators. Oceanic subsidies are manifestations of significant exchange of material between PWS and the Gulf of Alaska. Given

  6. Dolomitization in Late Jurassic-Early Cretaceous Platform Carbonates (Berdiga Formation), Ayralaksa Yayla (Trabzon), NE Turkey

    NASA Astrophysics Data System (ADS)

    Yıldız, Merve; Ziya Kırmacı, Mehmet; Kandemir, Raif

    2017-04-01

    ABSTRACT Pontides constitute an E-W trending orogenic mountain belt that extends about 1100 km along the northern side of Turkey from the immediate east of Istanbul to the Georgian border at the east. Tectono-stratigraphically, the Pontides are divided into three different parts: Eastern, Central, and Western Pontides. The Eastern Pontides, including the studied area, comprise an area of 500 km in length and 100 km in width, extending along the southeast coast of the Black Sea from the Kizilirmak and Yesilirmak Rivers in the vicinity of Samsun to the Little Caucasus. This area is bordered by the Eastern Black Sea basin to the north and the Ankara-Erzincan Neotethyan suture zone to the south. The Late Jurassic-Early Cretaceous platform carbonates are widely exposed in E-W direction in the Eastern Pontides (NE Turkey). The Platform carbonates shows varying lithofacies changing from supratidal to platform margin reef laterally and vertically, and was buried until the end of Late Cretaceous. The studied Ayralaksa Yayla (Trabzon, NE Turkey) area comprises one of the best typical exposures of formation in northern zone of Eastern Pontides. In this area, the lower parts of the formation are pervasively dolomitized by fabric-destructive and fabric-preserving replacement dolomite which are Ca-rich and nonstoichiometric (Ca56-66Mg34-44). Replacement dolomites (Rd) are represented by D18O values of -19.0 to -4.2 (VPDB), D13C values of 4.4 to 2.1 \\permil (VPDB) and 87Sr/86Sr ratios of 0.70889 to 0.70636. Petrographic and geochemical data indicate that Rd dolomites are formed prior to compaction at shallow-moderate burial depths from Late Jurassic-Early Cretaceous seawater and/or partly modified seawater as a result of water/rock interaction and they were recrystallized at elevated temperatures during subsequent burial. In the subsequent diagenetic process during the Late Cretaceous when the region became a magmatic arc, as a result of interaction with Early Jurassic volcanic

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

    NASA Astrophysics Data System (ADS)

    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

  8. Abundance profiling of extremely metal-poor stars and supernova properties in the early universe

    SciTech Connect

    Tominaga, Nozomu; Iwamoto, Nobuyuki; Nomoto, Ken'ichi, E-mail: tominaga@konan-u.ac.jp, E-mail: iwamoto.nobuyuki@jaea.go.jp, E-mail: nomoto@astron.s.u-tokyo.ac.jp

    2014-04-20

    After the big bang nucleosynthesis, the first heavy element enrichment in the universe was made by a supernova (SN) explosion of a population (Pop) III star (Pop III SN). The abundance ratios of elements produced from Pop III SNe are recorded in abundance patterns of extremely metal-poor (EMP) stars. The observations of the increasing number of EMP stars have made it possible to statistically constrain the explosion properties of Pop III SNe. We present Pop III SN models whose nucleosynthesis yields well reproduce, individually, the abundance patterns of 48 such metal-poor stars as [Fe/H] ≲ – 3.5. We then derivemore » relations between the abundance ratios of EMP stars and certain explosion properties of Pop III SNe: the higher [(C + N)/Fe] and [(C + N)/Mg] ratios correspond to the smaller ejected Fe mass and the larger compact remnant mass, respectively. Using these relations, the distributions of the abundance ratios of EMP stars are converted to those of the explosion properties of Pop III SNe. Such distributions are compared with those of the explosion properties of present day SNe: the distribution of the ejected Fe mass of Pop III SNe has the same peak as that of the present day SNe but shows an extended tail down to ∼10{sup –2}-10{sup –5} M {sub ☉}, and the distribution of the mass of the compact remnant of Pop III SNe is as wide as that of the present-day, stellar-mass black holes. Our results demonstrate the importance of large samples of EMP stars obtained by ongoing and future EMP star surveys and subsequent high-dispersion spectroscopic observations in clarifying the nature of Pop III SNe in the early universe.« less

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

    NASA Technical Reports Server (NTRS)

    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.

  10. Models and (some) Searches for CPT Violation: From Early Universe to the Present Era

    NASA Astrophysics Data System (ADS)

    Mavromatos, Nick E.

    2017-07-01

    In the talk, I review theoretical models, inspired by quantum gravity, that may violate CPT symmetry. The amount of violation today (which is constrained severely by a plethora of experiments that I will not describe due to lack of space) need not be the same with the one that occurred in the Early Universe,. In certain models, one can obtain a precise temperature dependence of CPT violating effects, which is such that these effects are significant during the radiation era of the Universe, but are damped quickly so that they do not to affect nucleosynthesis and are negligible in the present epoch (that is, beyond experimental detection with the current experimental sensitivity). The CPT Violation (CPTV) in these models may arise from special properties of the background over which the fields of the model are propagating upon and be responsible for the generation of a matter-antimatter asymmetry, where any CP violation effects could only assist in the creation of the asymmetry, the dominant effect being CPTV. However, there are cases, where the CPTV arises as a consequence of an ill-defined CPT operator due to decoherence as a result of quantum gravity environmental degrees of freedom, inaccessible to a low-energy observer. I also discuss briefly the current-era phenomenology of some of the above models; in particular, for the ones involving decoherence-induced CPT violation, I argue that entangled states of neutral mesons (Kaons or B-systems) can provide smoking-gun sensitive tests or even falsify some of these models. If CPT is ill-defined one may also encounter violations of the spin-statistics theorem, with possible consequences for the Pauli Exclusion Principle.

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

    PubMed Central

    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

  12. Quasars at Cosmic Dawn: Discoveries and Probes of the Early Universe

    NASA Astrophysics Data System (ADS)

    Wang, Feige; Wu, Xue-Bing; Fan, Xiaohui; Yang, Jinyi; Bian, Fuyan; McGreer, Ian D.; Green, Richard F.; Yang, Qian; Jiang, Linhua; Wang, Ran; DECaLS Team; UHS Team

    2017-01-01

    High redshift quasars, as the most luminous non-transient objects in the early universe, are the most promising tracers to address the history of cosmic reionization and how the origins of super-massive black hole (SMBH) are linked to galaxy formation and evolution. Over the last fifteen years, more than 100 quasars within the first billion years after the Big Bang have been discovered with the highest redshift at 7.1. We have developed a new method to select z>~6 quasars with both high efficiency and high completeness by combing optical and mid-IR Wide-field Infrared Survey Explorer (WISE) photometric data. We have applied this method to SDSS footprint and resulted in the discovery of the most luminous z>6 quasar ever discovered, which hosts a twelve billion solar mass black hole. I will present detailed follow-up observations of the host galaxies and environment of the most luminous quasars using HST, LBT and ALMA, in order to constrain early black hole growth and black hole/galaxy co-evolution at the highest redshift. I will also present initial results from a new quasar survey, which utilizes optical data from DECaLS, which is imaging 6700 deg^2 of sky down to z_AB˜23.0, and neaar-IR data from UHS and UKIDSS, which maps the whole northern sky at Decl.<+60deg. The combination of these datasets allows us to discover quasars at redshift z>~7 and to conduct a complete census of the faint quasar population at z~6.

  13. Early-career work location of Memorial University medical graduates: Why the decline in rural practice?

    PubMed

    Mathews, Maria; Ryan, Dana; Samarasena, Asoka

    2017-01-01

    In a previous study, we found a decline in the proportion of Memorial University of Newfoundland (MUN) medical alumni practising in rural areas, particularly in Newfoundland and Labrador. The current study focused on the work location of recent graduates and examined the predictors of working in rural Canada and in rural Newfoundland and Labrador within the first 15 years following graduation. We linked data from graduating class lists and the alumni and postgraduate databases with Scott's Medical Database to create a record of all graduates from 1973 to 2008, including their work location. We identified differences and significant predictors for each outcome and then described and compared the characteristics of 4 cohorts of graduating classes. In their early career, 127/1113 (11.4%) MUN medical graduates were working in rural Canada, and 57 (5.1%) were working in rural Newfoundland and Labrador. Having a rural background and being a family physician were predictors of working in rural Canada, and having a rural background, doing at least part of the residency at MUN, being from Newfoundland and Labrador and being a family physician were predictors of working in rural Newfoundland and Labrador. Seventy-four (13.6%) and 33 (6.1%) of 1989-1998 graduates worked in rural Canada and rural Newfoundland and Labrador, respectively, compared to 53 (9.3%) and 24 (4.2%), respectively, of 1999-2008 graduates. The proportion of MUN medical graduates who worked in rural communities early in their career decreased among recent cohorts. The results show the impact of changes in the characteristics of MUN medical graduates, who increasingly opt for specialist practice and residency training outside the province, and the important role of local postgraduate training.

  14. The Effect of Early Diagenesis on the 238U/235U Ratio of Platform Carbonates.

    NASA Astrophysics Data System (ADS)

    Tissot, F.; Chen, C.; Go, B. M.; Naziemiec, M.; Healy, G.; Swart, P. K.; Dauphas, N.

    2017-12-01

    In the past 15 years, the so-called non-traditional stable isotopes systems (e.g., Mg, Fe, Mo, U) have emerged as powerful tracers of both high-T and low-T geochemical processes (e.g., [1]). Of particular interest for paleoredox studies is the ratio of "stable" isotopes of U (238U/235U), which has the potential to track the global extent of oceanic anoxia (e.g., [2, 3]). Indeed, in the modern ocean, U exists in two main oxidation states, soluble U6+ and insoluble U4+, and has a mean residence time of 400 kyr ([4]), much longer than the global ocean mixing time (1-2 kyr). As such the salinity-normalized ocean is homogeneous with regards to both U concentrations and isotopes (δ238USW = -0.392±0.005 ‰, [2]). The value of δ238USW at any given time is therefore the balance between U input to the ocean, mainly from rivers, and U removal, mostly into biogenic carbonates, anoxic/euxinic sediments and suboxic/hypoxic sediments (e.g., [2, 5]). Because the 238U/235U ratio of the past ocean cannot be measured directly, it has to be estimated from the measurement of the 238U/235U ratio of a sedimentary rock and assuming a constant fractionation factor. Carbonates appear as a promising record since they span most of Earth's history, and the δ238U values of modern primary carbonate precipitates and well-preserved fossil aragonitic coral up to 600 ka are indistinguishable from that of seawater (e.g., [2, 6, 7]). Yet, the effect of secondary processes on the δ238U values of non-coral carbonates, which represent the bulk of the rock record, has only been studied in a handful of shallow samples (down to 40cm, [6]) and remains poorly understood. To investigate the effect of early diagenesis on the 238U/235U ratio of carbonates on the 30kyr to 1Myr timescale, we measured δ13C, δ18O, and δ238U in samples from a 220m long drill core from the Bahamas carbonate platform. In order to separate lattice bound U from secondary U we developed a leaching protocol applicable to carbonate

  15. The early diagenetic and PETROphysical behaviour of recent cold-water CARbonate mounds in Deep Environments (PETROCARDE)

    NASA Astrophysics Data System (ADS)

    Foubert, Anneleen; Pirlet, Hans; Thierens, Mieke; de Mol, Ben; Henriet, Jean-Pierre; Swennen, Rudy

    2010-05-01

    Sub-recent cold-water carbonate mounds localized in deeper slope settings on the Atlantic continental margins cannot be any longer neglected in the study of carbonate systems. They clearly play a major role in the dynamics of mixed siliciclastic-carbonate and/or carbonate-dominated continental slopes. Carbonate accumulation rates of cold-water carbonate mounds are about 4 to 12 % of the carbonate accumulation rates of tropical shallow-water reefs but exceed the carbonate accumulation rates of their slope settings by a factor of 4 to 12 (Titschack et al., 2009). These findings emphasize the importance of these carbonate factories as carbonate niches on the continental margins. The primary environmental architecture of such carbonate bodies is well-characterized. However, despite proven evidences of early diagenesis overprinting the primary environmental record (e.g. aragonite dissolution) (Foubert & Henriet, 2009), the extent of early diagenetic and biogeochemical processes shaping the petrophysical nature of mounds is until now not yet fully understood. Understanding (1) the functioning of a carbonate mound as biogeochemical reactor triggering early diagenetic processes and (2) the impact of early diagenesis on the petrophysical behaviour of a carbonate mound in space and through time are necessary (vital) for the reliable prediction of potential late diagenetic processes. Approaching the fossil carbonate mound record, through a profound study of recent carbonate bodies is innovative and will help to better understand processes observed in the fossil mound world (such as cementation, brecciation, fracturing, etc…). In this study, the 155-m high Challenger mound (Porcupine Seabight, SW of Ireland), drilled during IODP Expedition 307 aboard the R/V Joides Resolution (Foubert & Henriet, 2009), and mounds from the Gulf of Cadiz (Moroccan margin) will be discussed in terms of early diagenetic processes and petrophysical behaviour. Early differential diagenesis

  16. Climate Cycling on Early Mars Caused by the Carbonate-Silicate Cycle

    NASA Astrophysics Data System (ADS)

    Kasting, J. F.; Batalha, N. E.; Haqq-Misra, J. D.; Kopparapu, R.

    2016-12-01

    For decades, scientists have tried to explain the evidence for fluvial activity on early Mars, but a consensus has yet to emerge regarding the mechanism for producing it. One hypothesis suggests early Mars was warmed by a thick greenhouse atmosphere [1]. Another suggests early Mars was generally cold but was warmed occasionally by impacts or by episodes of enhanced volcanism [2,3], with warming possibly extended by cirrus clouds [4]. These latter hypotheses struggle to produce the amounts of rainfall needed to form the martian valleys, but are consistent with inferred low rates of weathering compared to Earth. We suggest that both schools of thought are partly correct. Mars experienced dramatic climate cycles with extended periods of glaciation punctuated by warm periods lasting up to 10 Myr [5]. Cycles of repeated glaciation and deglaciation occurred because stellar insolation was low, and because CO2 outgassing could not keep pace with CO2 consumption by silicate weathering followed by deposition of carbonates. In order to deglaciate early Mars, substantial outgassing of molecular hydrogen from Mars' reduced crust and mantle was also required, as our own climate model is unable to do this without adding some greenhouse warming from H2 [6,7]. Our hypothesis can be tested by future Mars exploration that better establishes the time scale for valley formation. References: [1] Pollack JB, Kasting JF, Richardson SM, Poliakoff K. 1987. Icarus 71: 203-24 [2] Halevy I, Head JW. 2014. Nature Geoscience 7: 865-8 [3] Segura TL, Toon OB, Colaprete A, Zahnle K. 2002. Science 298: 1977-80 [4] Urata RA, Toon OB. 2013. Icarus 226: 229-50 [5] Batalha NE, Kopparapu RK, Haqq-Misra JD, Kasting JF. submitted. Climate cycling on early Mars caused by the carbonate-silicate cycle. EPSL [6] Ramirez RM, Kopparapu R, Zugger ME, Robinson TD, Freedman R, Kasting JF. 2014. Nature Geosci 7: 59-63 [7] Batalha N, Domagal-Goldman SD, Ramirez R, Kasting JF. 2015. Icarus 258: 337-49

  17. Residual fluctuations in the matter and radiation distribution after the decoupling epoch. [of early universe

    NASA Technical Reports Server (NTRS)

    Silk, J.; Wilson, M. L.

    1980-01-01

    The residual spectra of matter and radiation fluctuations in the early universe are investigated, and the evolution of primordial adiabatic and isothermal fluctuations through the decoupling epoch is studied. Amplification of adiabatic density fluctuations during decoupling, or velocity 'overshoot', is largely suppressed by Compton drag. Consequently, the amplitude of density fluctuations entering the horizon prior to decoupling is larger than hitherto assumed in the adiabatic theory. Damping of primordial adiabatic density fluctuations by an order of magnitude occurs on mass-scales of 3 x 10 to the 13th solar masses (Omega = 1) or 10 to the 14th solar masses (Omega = 0.2). Comparison of the residual radiation fluctuations with observational limits indicates that the adiabatic theory is only acceptable if re-ionization of the intergalactic medium results in additional scattering of the radiation after decoupling. Primordial isothermal fluctuations are found to yield radiation fluctuations which are insensitive to the assumed spectrum and lie a factor of about 5 below current limits

  18. Dust-obscured star-forming galaxies in the early universe

    NASA Astrophysics Data System (ADS)

    Wilkins, Stephen M.; Feng, Yu; Di Matteo, Tiziana; Croft, Rupert; Lovell, Christopher C.; Thomas, Peter

    2018-02-01

    Motivated by recent observational constraints on dust reprocessed emission in star-forming galaxies at z ∼ 6 and above, we use the very large cosmological hydrodynamical simulation BLUETIDES to explore predictions for the amount of dust-obscured star formation in the early Universe (z > 8). BLUETIDES matches current observational constraints on both the UV luminosity function and galaxy stellar mass function and predicts that approximately 90 per cent of the star formation in high-mass (M* > 1010 M⊙) galaxies at z = 8 is already obscured by dust. The relationship between dust attenuation and stellar mass predicted by BLUETIDES is consistent with that observed at lower redshift. However, observations of several individual objects at z > 6 are discrepant with the predictions, though it is possible that their uncertainties may have been underestimated. We find that the predicted surface density of z ≥ 8 submm sources is below that accessible to current Herschel, SCUBA-2 and Atacama Large Millimetre Array (ALMA) submm surveys. However, as ALMA continues to accrue an additional surface area the population of z > 8 dust-obscured galaxies may become accessible in the near future.

  19. Lensing as a probe of early universe: from CMB to galaxies

    SciTech Connect

    Hassani, Farbod; Baghram, Shant; Firouzjahi, Hassan, E-mail: farbod@physics.sharif.edu, E-mail: baghram@sharif.edu, E-mail: firouz@ipm.ir

    The Cosmic Microwave Background (CMB) radiation lensing is a promising tool to study the physics of early universe. In this work we probe the imprints of deviations from isotropy and scale invariance of primordial curvature perturbation power spectrum on CMB lensing potential and convergence. Specifically, we consider a scale-dependent hemispherical asymmetry in primordial power spectrum. We show that the CMB lensing potential and convergence and also the cross-correlation of the CMB lensing and late time galaxy convergence can probe the amplitude and the scale dependence of the dipole modulation. As another example, we consider a primordial power spectrum with localmore » feature. We show that the CMB lensing and the cross-correlation of the CMB lensing and galaxy lensing can probe the amplitude and the shape of the local feature. We show that the cross correlation of CMB lensing convergence and galaxy lensing is capable to probe the effects of local features in power spectrum on smaller scales than the CMB lensing. Finally we showed that the current data can constrain the amplitude and moment dependence of dipole asymmetry.« less

  20. The nucleosynthetic origins and chemical evolution of phosphorus in the early universe

    NASA Astrophysics Data System (ADS)

    Frebel, Anna

    2013-10-01

    Relatively little is known about the chemical evolution of the element phosphorus, despite its relatively large abundance in the Sun and its importance for biological life. The goal of this archive proposal is to establish the chemical evolution trend of phosphorus, extending our knowledge from solar metallicity to stars with less than 1/1000th the solar metallicity.Previous studies have used weak near-infrared P I lines to establish phosphorus abundance trends from -1.0 < [Fe/H] < 0. We have identified a strong P I doublet in the UV at 2136 Angstroms, which is present in the spectra of 22 stars available in the HST archives. Our study will {1} improve on the limited observations of the abundance trend at high metallicity and extend it to metallicities lower by 2 dex and {2} determine whether [P/Fe] flattens out towards lower metallicities {like the alpha-elements Mg, Si, Ca, and Ti} or whether it continues to increase {like Co and Zn}. Our results will provide the first tight constraints on the nucleosynthesis of phosphorus and its production sites in the early Universe.We request one semester of funding to support a graduate student to lead the spectral analysis work, one month of summer salary, and miscellaneous travel and publication costs.

  1. Test anxiety in mathematics among early undergraduate students in a British university in Malaysia

    NASA Astrophysics Data System (ADS)

    Karjanto, Natanael; Yong, Su Ting

    2013-03-01

    The level of test anxiety in mathematics subjects among early undergraduate students at the University of Nottingham Malaysia Campus is studied in this article. The sample consists of 206 students taking several mathematics modules who completed the questionnaires on test anxiety just before they entered the venue for midterm examinations. The sample data include the differences in the context of academic levels, gender groups and nationality backgrounds. The level of test anxiety in mathematics is measured using seven Likert questionnaire statements adapted from the Test Anxiety Inventory describing one's emotional feeling before the start of an examination. In general, the result shows that the students who had a lower score expectation were more anxious than those who had a higher score expectation, but that they obtained a better score than the expected score. In the context of academic levels, gender groups and nationality backgrounds, there were no significant correlations between the level of test anxiety and the students' academic performance. The effect size of the correlation values ranged from extremely small to moderate.

  2. Squeezed states and graviton-entropy production in the early universe

    NASA Technical Reports Server (NTRS)

    Giovannini, Massimo

    1994-01-01

    Squeezed states are a very useful framework for the quantum treatment of tensor perturbations (i.e. gravitons production) in the early universe. In particular, the non equilibrium entropy growth in a cosmological process of pair production is completely determined by the associated squeezing parameter and is insensitive to the number of particles in the initial state. The total produced entropy may represent a significant fraction of the entropy stored today in the cosmic blackbody radiation, provided pair production originates from a change in the background metric at a curvature scale of the Planck order. Within the formalism of squeezed thermal states it is also possible to discuss the stimulated emission of gravitons from an initial thermal bath, under the action of the cosmic gravitational background field. We find that at low energy the graviton production is enhanced, if compared with spontaneous creation from the vacuum; as a consequence, the inflation scale must be lowered, in order not to exceed the observed CMB quadrupole anisotropy. This effect is important, in particular, for models based on a symmetry-breaking transition which require, as initial condition, a state of thermal equilibrium at temperatures higher than the inflation scale and in which inflation has a minimal duration.

  3. Composition and origin of Early Cambrian Tiantaishan phosphorite-Mn carbonate ores, Shaanxi Province, China

    USGS Publications Warehouse

    Hein, J.R.; Fan, D.; Ye, J.; Liu, T.; Yeh, H.-W.

    1999-01-01

    The Tiantaishan phosphorite-Mn carbonate ores occur in the Early Cambrian Tananpo Formation in complexly folded and faulted rocks located in southern Shaanxi Province. About 65 x 106 tonnes of 17% P2O5 ore reserves exist and Mn-ore reserves are about 8.3 x 106 tonnes of +18% Mn. The stratigraphic sequence in ascending order consists of black phyllite, black to gray phosphorite ore, black phyllite, rhodochrostone ore, Mn mixed-carbonates, and dolostone. Data are presented from microprobe mineral chemistry, whole-rock chemistry, stable isotopes of carbonates, X-ray mineralogy, petrographic and SEM observations, and statistical analysis of chemical data. The dominant ore-forming minerals are hydroxy- and carbonate fluorapatite and Ca rhodochrosite, with Mg kutnahorite and dolomite comprising the Mn mixed-carbonate section. Pyrite occurs in all rock types and alabandite (MnS) occurs throughout the rhodochrostone section. The mean P2O5 content of phosphorite is 31% and argillaceous phosphorite is 16%, while the mean MnO content of rhodochrostone ore is 37%. Phosphorite ores are massive, spheroidal, laminated, and banded, while rhodochrostone ores have oolitic, spheroidal, and granular fabrics. The most distinguishing characteristics of the ores are high total organic carbon (TOC) contents (mean 8.4%) in the phosphorite and high P2O5 contents (mean 2.7%) in the rhodochrostone ore. The atypically high TOC contents in the Tiantaishan phosphorite probably result from very strong productivity leading to high sedimentation rates accompanied by weak reworking of sediments; poor utilization of the organic matter by bacteria; and/or partial replacement of bacterial or algal mats by the apatite. The depositional setting of the ores was the margin of an epicontinental seaway created as a direct consequence of global processes that included break-up of a supercontinent, formation of narrow seaways, creation of extensive continental shelves, overturn of stagnant, metal-rich deep

  4. Evolution of Cupido and Coahuila carbonate platforms, early Cretaceous, northeastern Mexico

    USGS Publications Warehouse

    Lehmann, Christoph; Osleger, David A.; Montañez, Isabel P.; Sliter, William V.; Arnaud Vanneau, Annie; Banner, Jay L.

    1999-01-01

    The Cupido and Coahuila platforms of northeastern Mexico are part of the extensive carbonate platform system that rimmed the ancestral Gulf of Mexico during Barremian to Albian time. Exposures of Cupido and Coahuila lithofacies in several mountain ranges spanning an ∼80000 km2 area reveal information about platform morphology and composition, paleoenvironmental relations, and the chronology of platform evolution. New biostratigraphic data, integrated with carbon and strontium isotope stratigraphy, significantly improve chronostratigraphic relations across the region. These data substantially change previous age assignments of several formations and force a revision of the longstanding stratigraphy in the region. The revised stratigraphy and enhanced time control, combined with regional facies associations, allow the construction of cross sections, isopach maps, and time-slice paleogeographic maps that collectively document platform morphology and evolution.The orientation of the Cupido (Barremian-Aptian) shelf margin was controlled by the emergent Coahuila basement block to the northwest. The south-facing margin is a high-energy grainstone shoal, whereas the margin facing the ancestral Gulf of Mexico to the east is a discontinuous rudist-coral reef. A broad shelf lagoon developed in the lee of the Cupido margin, where as much as 660 m of cyclic peritidal deposits accumulated. During middle to late Aptian time, a major phase of flooding forced a retrograde backstep of the Cupido platform, shifting the locus of shallow-marine sedimentation northwestward toward the Coahuila block. This diachronous flooding event records both the demise of the Cupido shelf and the consequent initiation of the Coahuila ramp.The backstepped Coahuila ramp (Aptian-Albian) consisted of a shallow shoal margin separating an interior evaporitic lagoon from a low-energy, muddy deep ramp. More than 500 m of cyclic carbonates and evaporites accumulated in the evaporitic lagoon during early to

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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;…

  7. The origin of decoupled carbonate and organic carbon isotope signatures in the early Cambrian (ca. 542-520 Ma) Yangtze platform

    NASA Astrophysics Data System (ADS)

    Jiang, Ganqing; Wang, Xinqiang; Shi, Xiaoying; Xiao, Shuhai; Zhang, Shihong; Dong, Jin

    2012-02-01

    The early Cambrian (ca. 542-520 Ma) strata in South China record two prominent negative carbonate carbon isotope (δ13Ccarb) excursions of early Nemakit-Daldynian (N-D) and early Tommotian ages. Across each of these excursions, carbonate and organic carbon isotopes (δ13Ccarb and δ13Corg) are strongly decoupled. Regional correlation across a shelf-to-basin transect shows lateral heterogeneity of δ13Corg during the early-middle N-D but more homogenized δ13Corg values across the basin during the late N-D and Tommotian. The temporal and lateral variations in δ13Corg suggest that decoupled δ13Ccarb and δ13Corg across the N-D δ13Ccarb excursion were possibly caused by diagenetic alteration of organic matter and/or amplification of detrital organic carbon isotope signature in low-TOC carbonates. In contrast, decoupled δ13Ccarb and δ13Corg of the upper N-D and Tommotian were likely resulted from chemoautotrophic-methanotrophic biomass contribution to TOC in organic-rich black shale and carbonates. The decoupled δ13Ccarb-δ13Corg pattern from the lower N-D strata (ca. 542 Ma) shows striking similarities with those from the basal (ca. 635 Ma) and upper (ca. 551 Ma) Doushantuo Formation. In all three cases, decoupled δ13Ccarb-δ13Corg are seen in organic-poor carbonates (TOC ≤ 0.1‰) and coupled δ13Ccarb-δ13Corg occur in organic-rich black shale and carbonates at the end of the negative δ13Ccarb excursion. These similarities suggest that the shift from decoupled to coupled δ13Ccarb-δ13Corg has no causal link with the terminal oxidation of a large oceanic DOC reservoir. Given the pervasive anoxia/euxinia in Ediacaran-early Cambrian oceans, local DOC-rich environments may have been common, but a large oceanic DOC reservoir capable of buffering the δ13C of marine organic matter requires independent evidence.

  8. Rethinking Controls on the Long-Term Cenozoic Carbonate Compensation Depth: Case Studies across Late Paleocene - Early Eocene Warming and Late Eocene - Early Oligocene Cooling

    NASA Astrophysics Data System (ADS)

    Greene, S. E.; Ridgwell, A. J.; Schmidt, D. N.; Kirtland Turner, S.; Paelike, H.; Thomas, E.

    2014-12-01

    The carbonate compensation depth (CCD) is the depth below which negligible calcium carbonate is preserved in marine sediments. The long-term position of the CCD is often considered to be a powerful constraint on palaeoclimate and atmospheric CO2 concentration due to the requirement that carbonate burial balance riverine weathering over long timescales. The requirement that weathering and burial be in balance is clear, but it is less certain that burial compensates for changes in weathering via shoaling or deepening of the CCD. Because most carbonate burial occurs well above the CCD , changes in weathering fluxes may be primarily accommodated by increasing or decreasing carbonate burial at shallower depths, i.e., at or near the lysocline, the depth range over which carbonate dissolution markedly increases. Indeed, recent earth system modelling studies have suggested that the position of the CCD is relatively insensitive to changes in atmospheric pCO2. Additionally, studies have questioned the nature and strength of the relationship between the CCD, carbonate saturation state in the water column, and lysocline. To test the relationship between palaeoclimate and the location of the CCD, we reconstructed the global, long-term CCD behaviour across major Cenozoic climate transitions: the late Paleocene - early Eocene long-term warming trend (study interval ~58 to 49 Ma) and the late Eocene - early Oligocene cooling and glaciation (study interval ~38 to 27 Ma). We use Earth system modelling (GENIE) to explore the links between atmospheric pCO2 and the CCD, isolating and teasing apart the roles of total dissolved inorganic carbon, temperature, circulation, and productivity in determining the CCD.

  9. A Corrosion Sensor for Monitoring the Early-Stage Environmental Corrosion of A36 Carbon Steel

    PubMed Central

    Chen, Dong; Yen, Max; Lin, Paul; Groff, Steve; Lampo, Richard; McInerney, Michael; Ryan, Jeffrey

    2014-01-01

    An innovative prototype sensor containing A36 carbon steel as a capacitor was explored to monitor early-stage corrosion. The sensor detected the changes of the surface- rather than the bulk- property and morphology of A36 during corrosion. Thus it was more sensitive than the conventional electrical resistance corrosion sensors. After being soaked in an aerated 0.2 M NaCl solution, the sensor’s normalized electrical resistance (R/R0) decreased continuously from 1.0 to 0.74 with the extent of corrosion. Meanwhile, the sensor’s normalized capacitance (C/C0) increased continuously from 1.0 to 1.46. X-ray diffraction result indicates that the iron rust on A36 had crystals of lepidocrocite and magnetite. PMID:28788158

  10. Geochemistry of Precambrian carbonates. IV - Early Paleoproterozoic (2.25 +/- 0.25 Ga) seawater

    NASA Technical Reports Server (NTRS)

    Veizer, Jan; Clayton, R. N.; Hinton, R. W.

    1992-01-01

    The mineralogy, chemistry, and isotopic composition of the Malmani Dolomite, Duck Creek Dolomite, and Bruce 'Limestone' Member of the Espanola Formation are studied in an effort to restrict the first- and second-order variations in isotopic composition of Early Paleoproterozoic seawater. The diagenetic rank is found to increase in the order Duck Creek less than Bruce less than Malmani. The interpolation of alteration trends to 'best' value yields an estimate of 0.70550 for Sr-87/Sr-86. For delta C-13, the measured range of 0 +/- 1.5 percent PDB is similar to that observed for Phanerozoic marine carbonates, while the 'best' delta O-18 value for dolostones is -5 percent PDB, depleted in O-18 relative to Phanerozoic counterparts but comparable to estimates obtained for Archean facies. The isotope geochemistry and mineralogy of Bruce 'Limestone' Member is consistent with the proposition that the sequence was deposited in a lacustrine environment.

  11. Exploring the geochemical distribution of organic carbon in early land plants: a novel approach.

    PubMed

    Abbott, Geoffrey D; Fletcher, Ian W; Tardio, Sabrina; Hack, Ethan

    2018-02-05

    Terrestrialization depended on the evolution of biosynthetic pathways for biopolymers including lignin, cutin and suberin, which were concentrated in specific tissues, layers or organs such as the xylem, cuticle and roots on the submillimetre scale. However, it is often difficult, or even impossible especially for individual cells, to resolve the biomolecular composition of the different components of fossil plants on such a scale using the well-established coupled techniques of gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry. Here, we report the application of techniques for surface analysis to investigate the composition of Rhynia gwynne-vaughanii X-ray photoelectron spectroscopy of two different spots (both 300 µm × 600 µm) confirmed the presence of carbon. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) revealed 'chemical maps' (imaging mode with 300 nm resolution) of aliphatic and aromatic carbon in the intact fossil that correlate with the vascular structures observed in high-resolution optical images. This study shows that imaging ToF-SIMS has value for determining the location of the molecular components of fossil embryophytes while retaining structural information that will help elucidate how terrestrialization shaped the early evolution of land plant cell wall biochemistry.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'. © 2017 The Author(s).

  12. Earth's early atmosphere as seen from carbon and nitrogen isotopic analysis of Archean sediments

    NASA Technical Reports Server (NTRS)

    Gibson, E. K., Jr.; Carr, L. P.; Gilmour, I.; Pillinger, C. T.

    1986-01-01

    The origin and evolution of the Earth's early atmosphere has long been a topic of great interest but determination of actual compositions over geologic time is a difficult problem. However, recent systematic studies of stromatolite deposits (Precambrian Paleobiology Research Group) has extended our knowledge of Archean ecosystems. It has been shown that many stromatolite deposits have undergone negligible alteration since their time of formation. The discovery of primary fluid inclusions within unaltered 3.5 b.y. old Archiean sediments and the observation that the 3.3 b.y. old Barberton cherts have remained closed to argon loss and have not been subjected to thermal metamorphism suggests that an opportunity exists for the direct measurement of the volatile constituents present at their time of formation. Of primary interest to this study was the possibility that the stromatolites and other Archean sediments might retain a vestige of the atmosphere and thus afford an indication of the variations in carbon dioxide and nitrogen isotopic compositions with time. A suite of essentially unaltered Archean stromatolites and the cherts of different ages and geologic sites have been analyzed for their trapped carbon dioxide and nitrogen compositions by the stepped combustion extraction tech nique utilizing static mass spectrometers for the isotope measurements.

  13. Sedimentary evidence for enhanced hydrological cycling in response to rapid carbon release during the early Toarcian oceanic anoxic event

    NASA Astrophysics Data System (ADS)

    Izumi, Kentaro; Kemp, David B.; Itamiya, Shoma; Inui, Mutsuko

    2018-01-01

    A pronounced excursion in the carbon-isotope composition of biospheric carbon and coeval seawater warming during the early Toarcian (∼183 Ma) has been linked to the large-scale transfer of 12C-enriched carbon to the oceans and atmosphere. A European bias in the distribution of available data means that the precise pattern, tempo and global expression of this carbon cycle perturbation, and the associated environmental responses, remain uncertain. Here, we present a new cm-scale terrestrial-dominated carbon-isotope record through an expanded lower Toarcian section from Japan that displays a negative excursion pattern similar to marine and terrestrial carbon-isotope records documented from Europe. These new data suggest that 12C-enriched carbon was added to the biosphere in at least one rapid, millennial-scale pulse. Sedimentological analysis indicates a close association between the carbon-isotope excursion and high-energy sediment transport and enhanced fluvial discharge. Together, these data support the hypothesis that a sudden strengthening of the global hydrological cycle occurred in direct and immediate response to rapid carbon release and atmospheric warming.

  14. A simple model of universe describing the early inflation and the late accelerated expansion in a symmetric manner

    SciTech Connect

    Chavanis, Pierre-Henri

    We construct a simple model of universe which 'unifies' vacuum energy and radiation on the one hand, and matter and dark energy on the other hand in the spirit of a generalized Chaplygin gas model. Specifically, the phases of early inflation and late accelerated expansion are described by a generalized equation of state p/c{sup 2} = αρ+kρ{sup 1+1/n} having a linear component p = αρc{sup 2} and a polytropic component p = kρ{sup 1+1/n}c{sup 2}. For α= 1/3, n= 1 and k=−4/(3ρ{sub P}), where ρ{sub P}= 5.1610{sup 99} g/m{sup 3} is the Planck density, this equation of state describes themore » transition between the vacuum energy era and the radiation era. For t≥ 0, the universe undergoes an inflationary expansion that brings it from the Planck size l{sub P}= 1.6210{sup −35} m to a size a{sub 1}= 2.6110{sup −6} m on a timescale of about 23.3 Planck times t{sub P}= 5.3910{sup −44} s (early inflation). When t > t{sub 1}= 23.3t{sub P}, the universe decelerates and enters in the radiation era. We interpret the transition from the vacuum energy era to the radiation era as a second order phase transition where the Planck constant ℏ plays the role of finite size effects (the standard Big Bang theory is recovered for ℏ= 0). For α= 0, n=−1 and k=−ρ{sub Λ}, where ρ{sub Λ}= 7.0210{sup −24} g/m{sup 3} is the cosmological density, the equation of state p/c{sup 2} = αρ+kρ{sup 1+1/n} describes the transition from a decelerating universe dominated by pressureless matter (baryonic and dark matter) to an accelerating universe dominated by dark energy (late inflation). This transition takes place at a size a{sub 2}= 0.204l{sub Λ}. corresponding to a time t{sub 2}= 0.203t{sub Λ} where l{sub Λ}= 4.38 10{sup 26} m is the cosmological length and t{sub Λ}= 1.46 10{sup 18} s the cosmological time. The present universe turns out to be just at the transition between these two periods (t{sub 0}∼t{sub 2}). Our model gives the same results as the standard

  15. CHAIRMAN'S PREFACE: Nobel Symposium 79: The Birth and Early Evolution of Our Universe

    NASA Astrophysics Data System (ADS)

    Gustafsson, Bengt; Nilsson, Jan S.; Skagerstam, Bo-Sture

    1991-01-01

    It was in 1986 that we submitted a proposal to organize a Nobel Symposium on the topic "The Birth and Early Evolution of Our Universe", a subject not previously discussed at such a meeting. Our feeling at the time was that it would be appropriate to gather together international expertise on the deep and exciting connections between elementary physics and astrophysics/cosmology. In both these scientific disciplines there are wellknown "standard models"—the Glashow-Weinberg-Salam model of electroweak interactions and the Big-Bang cosmological model. The former model has now been tested to a very high accuracy. Progress in observational cosmology and astrophysics has on the other hand given strong support to the standard Big-Bang model as a realistic framework of cosmological evolution. The interesting fact, of course, is that the two standard models are not independent, and their predictions become interlinked when one considers the early, hot universe. It is now a wonderfully accepted piece of history that the constraint on the number of light neutrinos as obtained from the Big-Bang primordial nucleosynthesis agree very well with recent high-energy laboratory experiments. When our proposal was approved in 1989 we were very happy and honoured to invite a large number of internationally outstanding contributors to take part in the Symposium, almost all of whom were able to participate. It was, however, with deep regret and shock that their sudden deaths prevented us from inviting A Sakharov and Y Zeldovich. Their presence and wisdom was sadly missed. By choosing the beautiful village of Gräftåvallen, outside the town of Östesund, as the location of the Symposium, we hoped to provide a relaxing and stimulating atmosphere and also, possibly, almost twenty hours of sunlight a day for a week. The hosts of Gräftåvallen, Annika and Tommy Hagström, have to be thanked for making our stay both extremely successful and to a memorable experience. Our thanks also go to

  16. Early Retirement from Colleges and Universities: Considerations under the Employee Retirement Income Security Act.

    ERIC Educational Resources Information Center

    Shapiro, Larry E.

    1980-01-01

    Important considerations for institutions wanting to establish supplementary early retirement benefits to encourage the practice are outlined. Regulations concerning pension plans, tax-sheltered annuities, and deferred compensation are reviewed. Individually negotiated early retirement supplements are not recommended. (MSE)

  17. Etiology of early onset septicemia among neonates at the University College Hospital, Ibadan, Nigeria.

    PubMed

    Akindolire, Abimbola Ellen; Tongo, Olukemi; Dada-Adegbola, Hannah; Akinyinka, Olusegun

    2016-12-30

    Neonatal septicemia remains a major cause of newborn deaths in developing countries. Its burden is further compounded by the emergence of multidrug-resistant pathogens, which is related to a lack of antibiotic protocols resulting in unrestricted use of antibiotics. The absence of reliable antibiotic sensitivity testing makes the formulation of antibiotic guidelines and judicious use of antibiotics difficult. This study sought to identify the current bacterial agents associated with early onset septicemia (EOS; age <72 hours) and their antibiotic susceptibility patterns among neonates at the University College Hospital, Ibadan, Nigeria. A total of 202 inborn and outborn neonates with risk factors for or clinical features of septicemia in the first 72 hours of life had samples for blood cultures and antibiotic sensitivity patterns taken prior to treatment. Of the subjects, 95 (47.0%) were inborn and 107 (53.0%) outborn, with a M:F ratio of 1.3:1; 12.5% were culture positive, and the prevalence of EOS was 8.8/1,000 live births. The isolates were Staphylococcus aureus (52%), 30.7% of which were methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae (12%), Enterobacter aerogenes (8%), Enterococcus spp. (8%), Eschericia coli (4%), and other Gram-negatives (12%). All the isolates except Staphylococcus aureus were susceptible to ampicillin, ampicillin/sulbactam, amikacin, gentamicin, and third-generation cephalosporins. All MRSA were sensitive to amikacin, ciprofloxacin, and chloramphenicol, while all methicillin-sensitive Staphylococcus aureus were sensitive to ampicillin/sulbactam. Staphylococcus aureus was the commonest cause of EOS in our setting, with 30.7% of the Staphylococcus aureus isolates being MRSA. Only MRSA demonstrated multidrug resistance.

  18. Generation of the relic neutrino asymmetry in a hot plasma of the early universe

    NASA Astrophysics Data System (ADS)

    Semikoz, Victor B.; Dvornikov, Maxim

    The neutrino asymmetry in the early universe plasma, nν ‑ nν¯, is calculated both before and after the electroweak phase transition (EWPT). In the Standard Model, before EWPT, the leptogenesis is well known to be driven by the abelian anomaly in a massless hypercharge field. The generation of the neutrino asymmetry in the Higgs phase after EWPT, in its turn, has not been considered previously because of the absence of any quantum anomaly in an external electromagnetic field for such electroneutral particles as neutrino, unlike the Adler-Bell-Jackiw anomaly for charged left and right polarized massless electrons in the same electromagnetic field. Using the neutrino Boltzmann equation, modified by the Berry curvature term in the momentum space, we establish the violation of the macroscopic neutrino current in plasma after EWPT and exactly reproduce the nonconservation of the lepton current in the symmetric phase before EWPT arising in quantum field theory due to the nonzero lepton hypercharge and corresponding triangle anomaly in an external hypercharge field. In the last case, the nonconservation of the lepton current is derived through the kinetic approach without a computation of corresponding Feynman diagrams. Then, the new kinetic equation is applied for the calculation of the neutrino asymmetry accounting for the Berry curvature and the electroweak interaction with background fermions in the Higgs phase. Such an interaction generates a neutrino asymmetry through the electroweak coupling of neutrino currents with electromagnetic fields in plasma, which is ˜ GF2. It turns out that this effect is especially efficient for maximally helical magnetic fields.

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

    SciTech Connect

    Falceta-Gonçalves, D.; Kowal, G.

    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 growthmore » 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.« less

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Diagenetic history of late Oligocene-early Miocene carbonates in East Sabah, Malaysia

    NASA Astrophysics Data System (ADS)

    Zainal Abidin, N. S.; Raymond, R. R.; Bashah, N. S. I.

    2017-10-01

    Limestones are particularly susceptible to drastic early diagenesis modifications, mainly cementation and dissolution. During the early Miocene, a major tectonic deformation has caused a widespread of uplift in Sabah. This has resulted change in depositional environment from deep to shallow marine, which favours the deposition of Gomantong Limestone. This study aims to investigate the diagenetic history of Gomantong Limestone in East Sabah. Thorough understanding of the diagenetic processes may provide data to unravel the tectonic activities which affected the reservoir quality of the carbonates. Combining the data from comprehensive petrographic analysis, and Scanning Electron Microscopy (SEM) of 30 samples, two main cements type were identified. These are microcrystalline cement and Mg-calcite cement of granular and blocky mosaics which are dominantly seen in all samples. The sequence of diagenesis events are determined as (1) micritization; (2) grain scale compaction; (3) cementation (pore-filling); (4) mechanical compaction and cementation infilling fractures and (5) chemical compaction. These diagenetic events are interpreted as reflection of changes in diagenetic environment from shallow marine to deep burial. The massive cementation in the Gomantong Limestone has resulted into a poor reservoir quality.

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

    NASA Technical Reports Server (NTRS)

    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

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

    SciTech Connect

    Khodadi, M., E-mail: M.Khodadi@sbu.ac.ir; Sepangi, H.R., E-mail: hr-sepangi@sbu.ac.ir

    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 investigatemore » 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.« less

  4. Effect of Harvest Residue Management on Tree Productivity and Carbon Pools during Early Stand Development in a Loblolly Pine Plantation

    Treesearch

    Chris A. Maier; Kurt H. Johnsen; Phillip Dougherty; Daniel McInnis; Pete Anderson; Steve Patterson

    2012-01-01

    Soil incorporation of postharvest forest floor or logging residues during site preparation increased mineral soil carbon (C) and nitrogen (N) concentration and had a differential effect on early stand growth in a clonal loblolly pine (Pinus taeda L.) plantation. Incorporating 25 Mg ha

  5. 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

    NASA Astrophysics Data System (ADS)

    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.

  6. First Look at a Major Transition Period in the Early Universe

    NASA Astrophysics Data System (ADS)

    1997-08-01

    New Observations of Intergalactic Helium Absorption Observations of the bright southern quasar HE 2347-4342 with telescopes at the ESO La Silla Observatory and with the NASA/ESA Hubble Space Telescope (HST) have provided a group of European astronomers [1] with an exceptional glimpse into an early, still unexplored transition period of the Universe. At that time, many billions of years ago, some of the enormous gaseous clouds of hydrogen and helium left over from the Big Bang had not yet been fully ionized by the increasingly strong radiation from emerging galaxies and stars. In recent years astronomers have successfully `looked back' towards this period, but the new observations of HE 2347-4342 have now homed in on an important transitionary epoch during the evolution of the young Universe. Searching for clear views towards bright quasars As has been the case for many other important scientific achievements, this observational breakthrough was preceded by a long and tedious period of careful preparatory work. It began in 1989, when Dieter Reimers and his collaborators from the University of Hamburg (Germany) initiated a spectral survey of the entire southern sky with the 1-metre ESO Schmidt Telescope at La Silla. The aim was to find bright quasars , a rare class of remote galaxies with unusually bright and energetic centres. They would then be studied in greater detail with other, larger telescopes. For this programme, a large objective prism is placed in front of the telescope, allowing the simultaneous recording on a large photographic plate of spectra of about 40,000 celestial objects in a 5 o x 5 o sky field. The plates are sent to Hamburg where they are scanned (digitized) in a microphotometer and automatically searched for spectra of quasars. Until now, more than 400 plates have been obtained. One of the main goals of this vast programme is to find bright and distant quasars, in particular those whose light reaches us along relatively unobstructed paths. Or

  7. Early land use and centennial scale changes in lake-water organic carbon prior to contemporary monitoring.

    PubMed

    Meyer-Jacob, Carsten; Tolu, Julie; Bigler, Christian; Yang, Handong; Bindler, Richard

    2015-05-26

    Organic carbon concentrations have increased in surface waters across parts of Europe and North America during the past decades, but the main drivers causing this phenomenon are still debated. A lack of observations beyond the last few decades inhibits a better mechanistic understanding of this process and thus a reliable prediction of future changes. Here we present past lake-water organic carbon trends inferred from sediment records across central Sweden that allow us to assess the observed increase on a centennial to millennial time scale. Our data show the recent increase in lake-water carbon but also that this increase was preceded by a landscape-wide, long-term decrease beginning already A.D. 1450-1600. Geochemical and biological proxies reveal that these dynamics coincided with an intensification of human catchment disturbance that decreased over the past century. Catchment disturbance was driven by the expansion and later cessation of widespread summer forest grazing and farming across central Scandinavia. Our findings demonstrate that early land use strongly affected past organic carbon dynamics and suggest that the influence of historical landscape utilization on contemporary changes in lake-water carbon levels has thus far been underestimated. We propose that past changes in land use are also a strong contributing factor in ongoing organic carbon trends in other regions that underwent similar comprehensive changes due to early cultivation and grazing over centuries to millennia.

  8. The Chemistry of Population III Supernova Ejecta. II. The Nucleation of Molecular Clusters as a Diagnostic for Dust in the Early Universe

    NASA Astrophysics Data System (ADS)

    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.

  9. Carbonate petrography, kerogen distribution, and carbon and oxygen isotope variations in an early Proterozoic transition from limestone to iron-formation deposition, Transvaal Supergroup, South Africa

    NASA Technical Reports Server (NTRS)

    Beukes, N. J.; Klein, C.; Kaufman, A. J.; Hayes, J. M.

    1990-01-01

    The transition zone comprises Campbellrand microbialaminated (replacing "cryptalgalaminate") limestone and shale, with minor dolomite, conformably overlain by the Kuruman Iron Formation of which the basal part is characterized by siderite-rich microbanded iron-formation with minor magnetite and some hematite-containing units. The iron-formation contains subordinate intraclastic and microbialaminated siderite mesobands and was deposited in deeper water than the limestones. The sequence is virtually unaltered with diagenetic mineral assemblages reflecting a temperature interval of about 110 degrees to 170 degrees C and pressures of 2 kbars. Carbonate minerals in the different rock types are represented by primary micritic precipitates (now recrystallized to microsparite), early precompactional sparry cements and concretions, deep burial limpid euhedral sparites, and spar cements precipitated from metamorphic fluids in close contact with diabase sills. Paragenetic pathways of the carbonate minerals are broadly similar in all lithofacies with kerogen intimately associated with them. Kerogen occurs as pigmentation in carbonate crystals, as reworked organic detritus in clastic-textured carbonate units, and as segregations of kerogen pigment around late diagenetic carbonate crystals. Locally kerogen may also be replaced by carbonate spar. Carbon isotope compositions of the carbonate minerals and kerogen are dependent on their mode of occurrence and on the composition of the dominant carbonate species in a specific lithofacies. Integration of sedimentary, petrographic, geochemical, and isotopic results makes it possible to distinguish between depositional, early diagenetic, deep burial, and metamorphic effects on the isotopic compositions of the carbonate minerals and the kerogen in the sequence. Major conclusions are that deep burial thermal decarboxylation led to 13C depletion in euhedral ferroan sparites and 13C enrichment in kerogen (organic carbon). Metamorphic

  10. First look at a major transition period in the early Universe

    NASA Astrophysics Data System (ADS)

    1997-08-01

    in ESO PR Photo 22b/97 which shows its overall spectrum. Note in particular the intensity increase towards the ultraviolet part (to the left in the diagram) due to the unusually `clear view' in this direction. New observations of HE 2347-4342 have now provided important information, not only about the quasar itself, but especially about the conditions in the surrounding intergalactic medium at this early time. Early evolution of the Universe There is general agreement among most scientists that the Universe emanated from a hot and extremely dense initial state in the so-called Big Bang. Just three minutes later, the production of enormous quantities of hydrogen and helium nuclei of protons and neutrons came to an end. Lots of free electrons were moving around and the numerous photons were scattered from these and the `naked' atomic nuclei. After some 100,000 years, the Universe had cooled down to a few thousand degrees and the nuclei and electrons combined to form atoms. The photons were then no longer scattered and the Universe became transparent. Cosmologists refer to this moment as the recombination epoch. The microwave background radiation we now observe from all directions gives a picture of the state of great homogeneity in the Universe at that epoch. In the next phase the primeval atoms, more than 99% of which were of hydrogen and helium, moved together and began to form huge clouds from which galaxies and stars later emerged. When the first generation of stars and, somewhat later, of quasars, had formed, their intensive ultraviolet radiation began to knock off electrons from the hydrogen and helium atoms. Now the intergalactic gas again became ionized [4] in steadily growing spheres around the ionizing sources. This is the so-called re-ionization epoch. Is it possible to observe the re-ionization epoch directly? It is believed that a sufficient number of energetic photons to cause re-ionization of most of the primeval hydrogen atoms in intergalactic space had

  11. Architecture and evolution of an Early Permian carbonate complex on a tectonically active island in east-central California

    USGS Publications Warehouse

    Stevens, Calvin H.; Magginetti, Robert T.; Stone, Paul

    2015-01-01

    The newly named Upland Valley Limestone represents a carbonate complex that developed on and adjacent to a tectonically active island in east-central California during a brief interval of Early Permian (late Artinskian) time. This lithologically unique, relatively thin limestone unit lies within a thick sequence of predominantly siliciclastic rocks and is characterized by its high concentration of crinoidal debris, pronounced lateral changes in thickness and lithofacies, and a largely endemic fusulinid fauna. Most outcrops represent a carbonate platform and debris derived from it and shed downslope, but another group of outcrops represents one or possibly more isolated carbonate buildups that developed offshore from the platform. Tectonic activity in the area occurred before, probably during, and after deposition of this short-lived carbonate complex.

  12. Edinburgh University, Schools and the Civil Service in the Early Twentieth Century

    ERIC Educational Resources Information Center

    Anderson, Robert David

    2013-01-01

    This article is a case study of the relation between urban schooling and university education, using two main sources. Data on the schools attended by history students at Edinburgh University between 1899 and 1933 illustrate the diversity and social ranking of schools in the city. New higher grade schools had a key role in increasing access to…

  13. A Universal Good: Expanding Voluntary, Early Learning Opportunities for Illinois' Young Children.

    ERIC Educational Resources Information Center

    Noble, Sean

    This report was written to stimulate discussion about the potential and need for expanding access to voluntary, high-quality early childhood care and education programs in Illinois. The report compiles 13 short articles pertaining to early learning as follows: (1) "Ready to Succeed: Preparing Children for School, and for Life"; (2)…

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

    PubMed

    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.

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

    PubMed

    Anninos, Peter

    1998-01-01

    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 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 those calculations designed to test different models of cosmology against the observed Universe.

  16. Altered carbon cycling and coupled changes in Early Cretaceous weathering patterns: Evidence from integrated carbon isotope and sandstone records of the western Tethys

    NASA Astrophysics Data System (ADS)

    Wortmann, Ulrich Georg; Herrle, Jens Olaf; Weissert, Helmut

    2004-03-01

    In this study we investigate if a major perturbation of the Early Cretaceous carbon cycle was accompanied by altered weathering and erosion rates. The large Aptian carbon isotope anomaly records the response of the biosphere to widespread volcanic activity and probably resulting changes in atmospheric pCO2 levels. Elevated pCO2 levels should also result in an accelerated hydrological cycle and increased silicate weathering, creating a negative feedback loop removing CO2 from the atmosphere. We propose to interpret the widespread occurrence of quartz sandstones in the Tethys-Atlantic seaway as a result of altered weathering and erosion rates in the wake of the Aptian carbon cycle excursion. We challenge the traditional notion that these are 'flysch' deposits associated with Early Cretaceous orogenic movements in the western Tethys. We propose that these sandstones were most likely part of a large conveyor belt system, acting along the Iberian and European margin of the Tethys seaway. Using chemostratigraphic correlations, we show that the activity of this system was only short-lived and coeval with changes in coastal ecology and the Aptian carbon cycle perturbations. We tentatively relate the existence of this system to a transient climate regime, characterized by fluctuating pCO2 levels.

  17. A terrestrial Eocene stack: tying terrestrial lake ecology to marine carbon cycling through the Early Eocene Climatic Optimum

    NASA Astrophysics Data System (ADS)

    Grogan, D. S.; Whiteside, J. H.; Musher, D.; Rosengard, S. Z.; Vankeuren, M. A.; Pancost, R. D.

    2010-12-01

    The lacustrine Green River Formation is known to span ≥15 million years through the early-middle Eocene, and recent work on radioisotopic dating has provided a framework on which to build ties to the orbitally-tuned marine Eocene record. Here we present a spliced stack of Fischer assay data from drilled cores of the Green River Formation that span both an East-West and a North-South transect of the Uinta Basin of Utah. Detailed work on two cores demonstrate that Fischer assay measurements covary with total organic carbon and bulk carbon isotopes, allowing us to use Fisher assay results as a representative carbon cycling proxy throughout the stack. We provide an age model for this core record by combining radioisotopic dates of tuff layers with frequency analysis of Fischer assay measurements. Identification of orbital frequencies tied directly to magnetochrons through radioisotopic dates allows for a direct comparison of the terrestrial to the marine Eocene record. Our analysis indicates that the marker beds used to correlate the stack cores represent periods of enhanced lake productivity and extreme carbon burial; however, unlike the hyperthermal events that are clearly marked in the marine Eocene record, the hydrocarbon-rich "Mahogany Bed" period of burial does not correspond to a clear carbon isotope excursion. This suggests that the terrestrial realm may have experienced extreme ecological responses to relatively small perturbations in the carbon cycle during the Early Eocene Climatic Optimum. To investigate the ecological responses to carbon cycle perturbations through the hydrocarbon rich beds, we analyzed a suite of microbial biomarkers, finding evidence for cyanobacteria, dinoflagellates, and potentially green sulfur bacteria. These taxa indicate fluctuating oxic/anoxic conditions in the lake during abrupt intervals of carbon burial, suggesting a lake biogeochemical regime with no modern analogues.

  18. Carbon nanotube-embedded advanced aerospace composites for early-stage damage sensing

    NASA Astrophysics Data System (ADS)

    Nataraj, Latha; Coatney, Michael; Cain, Jason; Hall, Asha

    2018-03-01

    Fiber reinforced polymer (FRP) composites featuring outstanding fatigue performance, high specific stiffness and strength, and low density have evolved as critical structural materials in aerospace applications. Microscale damage such as fiber breakage, matrix cracking, and delamination could occur in layered composites compromising structural integrity, emphasizing the critical need to monitor structural health. Early damage detection would lead to enhanced reliability, lifetime, and performance while minimizing maintenance time, leading to enormous scientific and technical interest in realizing physically stable, quick responding, and cost effective strain sensing materials, devices, and techniques with high sensitivity over a broad range of the practical strain spectrum. Today's most commonly used strain sensing techniques are metal foil strain gauges and optical fiber sensors. Metal foil gauges offer high stability and cost-effectiveness but can only be surface-mounted and have a low gauge factor. Optical fibers require expensive instrumentation, are mostly insensitive to cracks parallel to the fiber orientation and may lead to crack initiation as the diameter is larger than that of the reinforcement fibers. Carbon nanotubes (CNTs) have attracted much attention due to high aspect ratio and superior electrical, thermal, and mechanical properties. CNTs embedded in layered composites have improved performance. A variety of CNT architectures and configurations have shown improved piezoresistive behavior and stability for sensing applications. However, scaling up and commercialization remain serious challenges. The current study investigates a simple, cost effective and repeatable technique for highly sensitive, stable, linear and repeatable strain sensing for damage detection by integrating CNT laminates into composites.

  19. Plasma-Enabled Carbon Nanostructures for Early Diagnosis of Neurodegenerative Diseases

    PubMed Central

    Pineda, Shafique; Han, Zhao Jun; Ostrikov, Kostya (Ken)

    2014-01-01

    Carbon nanostructures (CNs) are amongst the most promising biorecognition nanomaterials due to their unprecedented optical, electrical and structural properties. As such, CNs may be harnessed to tackle the detrimental public health and socio-economic adversities associated with neurodegenerative diseases (NDs). In particular, CNs may be tailored for a specific determination of biomarkers indicative of NDs. However, the realization of such a biosensor represents a significant technological challenge in the uniform fabrication of CNs with outstanding qualities in order to facilitate a highly-sensitive detection of biomarkers suspended in complex biological environments. Notably, the versatility of plasma-based techniques for the synthesis and surface modification of CNs may be embraced to optimize the biorecognition performance and capabilities. This review surveys the recent advances in CN-based biosensors, and highlights the benefits of plasma-processing techniques to enable, enhance, and tailor the performance and optimize the fabrication of CNs, towards the construction of biosensors with unparalleled performance for the early diagnosis of NDs, via a plethora of energy-efficient, environmentally-benign, and inexpensive approaches. PMID:28788112

  20. A warm or a cold early Earth? New insights from a 3-D climate-carbon model

    NASA Astrophysics Data System (ADS)

    Charnay, Benjamin; Le Hir, Guillaume; Fluteau, Frédéric; Forget, François; Catling, David C.

    2017-09-01

    Oxygen isotopes in marine cherts have been used to infer hot oceans during the Archean with temperatures between 60 °C (333 K) and 80 °C (353 K). Such climates are challenging for the early Earth warmed by the faint young Sun. The interpretation of the data has therefore been controversial. 1D climate modeling inferred that such hot climates would require very high levels of CO2 (2-6 bars). Previous carbon cycle modeling concluded that such stable hot climates were impossible and that the carbon cycle should lead to cold climates during the Hadean and the Archean. Here, we revisit the climate and carbon cycle of the early Earth at 3.8 Ga using a 3D climate-carbon model. We find that CO2 partial pressures of around 1 bar could have produced hot climates given a low land fraction and cloud feedback effects. However, such high CO2 partial pressures should not have been stable because of the weathering of terrestrial and oceanic basalts, producing an efficient stabilizing feedback. Moreover, the weathering of impact ejecta during the Late Heavy Bombardment (LHB) would have strongly reduced the CO2 partial pressure leading to cold climates and potentially snowball Earth events after large impacts. Our results therefore favor cold or temperate climates with global mean temperatures between around 8 °C (281 K) and 30 °C (303 K) and with 0.1-0.36 bar of CO2 for the late Hadean and early Archean. Finally, our model suggests that the carbon cycle was efficient for preserving clement conditions on the early Earth without necessarily requiring any other greenhouse gas or warming process.

  1. Dioctahedral Phyllosilicates Versus Zeolites and Carbonates Versus Zeolites Competitions as Constraints to Understanding Early Mars Alteration Conditions

    NASA Astrophysics Data System (ADS)

    Viennet, Jean-Christophe; Bultel, Benjamin; Riu, Lucie; Werner, Stephanie C.

    2017-11-01

    Widespread occurrence of Fe,Mg-phyllosilicates has been observed on Noachian Martian terrains. Therefore, the study of Fe,Mg-phyllosilicate formation, in order to characterize early Martian environmental conditions, is of particular interest to the Martian community. Previous studies have shown that the investigation of Fe,Mg-smectite formation alone helps to describe early Mars environmental conditions, but there are still large uncertainties in terms of pH range, oxic/anoxic conditions, etc. Interestingly, carbonates and/or zeolites have also been observed on Noachian surfaces in association with the Fe,Mg-phyllosilicates. Consequently, the present study focuses on the dioctahedral/trioctahedral phyllosilicate/carbonate/zeolite formation as a function of various CO2 contents (100% N2, 10% CO2/90% N2, and 100% CO2), from a combined approach including closed system laboratory experiments for 3 weeks at 120°C and geochemical simulations. The experimental results show that as the CO2 content decreases, the amount of dioctahedral clay minerals decreases in favor of trioctahedral minerals. Carbonates and dioctahedral clay minerals are formed during the experiments with CO2. When Ca-zeolites are formed, no carbonates and dioctahedral minerals are observed. Geochemical simulation aided in establishing pH as a key parameter in determining mineral formation patterns. Indeed, under acidic conditions dioctahedral clay minerals and carbonate minerals are formed, while trioctahedral clay minerals are formed in basic conditions with a neutral pH value of 5.98 at 120°C. Zeolites are favored from pH ≳ 7.2. The results obtained shed new light on the importance of dioctahedral clay minerals versus zeolites and carbonates versus zeolites competitions to better define the aqueous alteration processes throughout early Mars history.

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

    NASA Astrophysics Data System (ADS)

    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. Correlating carbon and oxygen isotope events in early to middle Miocene shallow marine carbonates in the Mediterranean region using orbitally tuned chemostratigraphy and lithostratigraphy

    PubMed Central

    Piller, Werner E.; Reuter, Markus; Harzhauser, Mathias

    2015-01-01

    Abstract During the Miocene prominent oxygen isotope events (Mi‐events) reflect major changes in glaciation, while carbonate isotope maxima (CM‐events) reflect changes in organic carbon burial, particularly during the Monterey carbon isotope excursion. However, despite their importance to the global climate history they have never been recorded in shallow marine carbonate successions. The Decontra section on the Maiella Platform (central Apennines, Italy), however, allows to resolve them for the first time in such a setting during the early to middle Miocene. The present study improves the stratigraphic resolution of parts of the Decontra section via orbital tuning of high‐resolution gamma ray (GR) and magnetic susceptibility data to the 405 kyr eccentricity metronome. The tuning allows, within the established biostratigraphic, sequence stratigraphic, and isotope stratigraphic frameworks, a precise correlation of the Decontra section with pelagic records of the Mediterranean region, as well as the global paleoclimatic record and the global sea level curve. Spectral series analyses of GR data further indicate that the 405 kyr orbital cycle is particularly well preserved during the Monterey Event. Since GR is a direct proxy for authigenic uranium precipitation during increased burial of organic carbon in the Decontra section, it follows the same long‐term orbital pacing as observed in the carbon isotope records. The 405 kyr GR beat is thus correlated with the carbon isotope maxima observed during the Monterey Event. Finally, the Mi‐events can now be recognized in the δ18O record and coincide with plankton‐rich, siliceous, or phosphatic horizons in the lithology of the section. PMID:27546980

  4. Correlating carbon and oxygen isotope events in early to middle Miocene shallow marine carbonates in the Mediterranean region using orbitally tuned chemostratigraphy and lithostratigraphy

    NASA Astrophysics Data System (ADS)

    Auer, Gerald; Piller, Werner E.; Reuter, Markus; Harzhauser, Mathias

    2015-04-01

    During the Miocene prominent oxygen isotope events (Mi-events) reflect major changes in glaciation, while carbonate isotope maxima (CM-events) reflect changes in organic carbon burial, particularly during the Monterey carbon isotope excursion. However, despite their importance to the global climate history they have never been recorded in shallow marine carbonate successions. The Decontra section on the Maiella Platform (central Apennines, Italy), however, allows to resolve them for the first time in such a setting during the early to middle Miocene. The present study improves the stratigraphic resolution of parts of the Decontra section via orbital tuning of high-resolution gamma ray (GR) and magnetic susceptibility data to the 405 kyr eccentricity metronome. The tuning allows, within the established biostratigraphic, sequence stratigraphic, and isotope stratigraphic frameworks, a precise correlation of the Decontra section with pelagic records of the Mediterranean region, as well as the global paleoclimatic record and the global sea level curve. Spectral series analyses of GR data further indicate that the 405 kyr orbital cycle is particularly well preserved during the Monterey Event. Since GR is a direct proxy for authigenic uranium precipitation during increased burial of organic carbon in the Decontra section, it follows the same long-term orbital pacing as observed in the carbon isotope records. The 405 kyr GR beat is thus correlated with the carbon isotope maxima observed during the Monterey Event. Finally, the Mi-events can now be recognized in the δ18O record and coincide with plankton-rich, siliceous, or phosphatic horizons in the lithology of the section.

  5. Carbon-isotope stratigraphy of Early Cretaceous (Urgonian) shoal-water deposits: Diachronous changes in carbonate-platform production in the north-western Tethys

    NASA Astrophysics Data System (ADS)

    Huck, S.; Heimhofer, U.; Immenhauser, A.; Weissert, H.

    2013-05-01

    Carbonate platforms are highly sensitive ecological systems that typically show rapid and characteristic response modes to environmental and climatic changes acting both on a regional scale and global scale. A widely accepted hypothesis proposes that the Late Barremian stepwise establishment of the Urgonian carbonate platform on the Northern Tethyan shelf was related to a gradual change from predominantly humid towards more arid greenhouse conditions. This climate change resulted in the reorganisation of the carbonate platform ecosystem from heterozoan towards photozoan-dominated assemblages and a decrease of organic-matter burial in Tethyan and Boreal basins. In order to decipher the palaeoenvironmental and climatic boundary conditions of these major changes in neritic and pelagic settings, a precise chronostratigraphy of Urgonian carbonate platform evolution is needed. Here, we provide an integrated stratigraphic framework of Lower Barremian to Lower Aptian Urgonian carbonate platform sections (Cluses, Forclaz) located at the northern rim of the Tethys (Subalpine Chains, ESE France), with special focus on sedimentological analyses and high-resolution carbon-isotope stratigraphy. A characteristic Barremian-Aptian carbon-isotope pattern permits precise platform-to-basin correlation with cyclostratigraphic and ammonite-dated pelagic and hemipelagic Tethyan sections in the Vocontian Trough (Angles/Combe-Lambert/Glaise) and Umbria Marche Basin (Gorgo a Cerbara). Similar to Helvetic shoal-water settings, the carbonate platform in the Subalpine Chains experienced a gradual transition from heterozoan- to photozoan-dominated ecosystems. This biogenic pattern points to a gradual change of the carbonate platform after the so-called "Early Barremian crisis" towards an oligotrophic rimmed platform system (Urgonian Limestone Formation). According to the chronostratigraphy of Urgonian carbonate platform evolution in the Subalpine Chains established here, the installation of a

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

    SciTech Connect

    Pashitskii, E. A., E-mail: pashitsk@iop.kiev.ua; Pentegov, V. I., E-mail: pentegov@iop.kiev.ua

    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,more » 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}.« less

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

    PubMed

    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.

  8. Heavy element synthesis in the oldest stars and the early Universe.

    PubMed

    Cowan, John J; Sneden, Christopher

    2006-04-27

    The first stars in the Universe were probably quite different from those born today. Composed almost entirely of hydrogen and helium (plus a tiny trace of lithium), they lacked the heavier elements that determine the formation and evolution of younger stars. Although we cannot observe the very first stars--they died long ago in supernovae explosions--they created heavy elements that were incorporated into the next generation. Here we describe how observations of heavy elements in the oldest surviving stars in our Galaxy's halo help us understand the nature of the first stars--those responsible for the chemical enrichment of our Galaxy and Universe.

  9. Detection of early stage prostate cancer by using a simple carbon nanotube@paper biosensor.

    PubMed

    Ji, Sungkyung; Lee, Myeongsoon; Kim, Don

    2018-04-15

    This study is an investigation for an inexpensive, simple and sensitive biosensor to detect prostate cancer using bioactivated-multi wall carbon nanotubes (MWCNTs, diameter of 20nm, length of 5µm) and a micro-pore filter paper (pore size of 0.45µm). For the immunoassay of prostate specific antigen (PSA), which is a biomarker of prostate cancer, MWCNTs were activated with PSA antibody (monoclonal antibody of the prostate specific antigen) by using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide sodium salt (NHSS). The activated MWCNTs were deposited on the micro-pore filter paper to use as a biosensor. The prepared biosensor can assay from 0 to 500ng/mL of PSA level within 2h with the detection limit of 1.18ng/mL by the measurement of resistance change. The resistance change was caused by site selective interaction between PSA and PSA-antigen with an inexpensive bench top digital multimeter (5 1/2 digits). The detection range and sensitivity of the prepared sensor are good enough to diagnose the early stage of prostate cancer (> 4ng/mL of PSA). This paper-based biosensor is about 20 times cheaper (fabricated biosensor price: 2.4 $) and over 10 times faster than enzyme-linked immunosorbent assay (ELISA), which is a general method for the detection of a specific protein in the modernized hospitals. Furthermore, the maximum detection limit is about 50 times higher than ELISA. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Early Comparative Outcomes of Carbon Fiber Reinforced Polymer Plate in the Fixation of Distal Femur Fractures.

    PubMed

    Mitchell, Phillip M; Lee, Adam K; Collinge, Cory A; Ziran, Bruce H; Hartley, Kate G; Jahangir, A Alex

    2018-05-16

    To evaluate the early clinical results of distal femur fractures treated with carbon fiber reinforced - polyetheretherketone (CFR-PEEK) plates compared to stainless steel (SS) lateral locking plates. Retrospective comparative cohort study SETTING:: ACS Level I trauma center. Twenty-two patients (11 SS, 11 CFR-PEEK) with closed distal femur fractures treated by a single surgeon over a 6-year period. Nonunion, hardware failure, reoperation, time to full weight bearing, and time ` union were assessed. The CFR-PEEK cohort was on average older (71 vs. 57 years, p=0.03) and more likely to have diabetes (p=0.02). Nonunion was diagnosed in 4/11 (36%) patients in the SS group and 1/11 (9%) patients in the CFR-PEEK group (p=0.12). Hardware failure occurred in two SS patients (18%) compared to none in the CFR-PEEK group (p=0.14). Time to full weight bearing was similar between groups occurring at 9.9 weeks and 12.4 weeks in the CFR-PEEK and SS groups, respectively (p=0.23). Time to radiographic union averaged 12.4 weeks in the SS group and 18.7 weeks in the CFR-PEEK group (p=0.26). There were 4 reoperations in the SS group and one in the CFR-PEEK group (p=0.12). CFR-PEEK plates show encouraging short-term results in the treatment of distal femur fractures with a comparable nonunion, reoperation, and hardware failure rates to those treated with SS plates. This data suggests CFR-PEEK plates may be a viable alternative to SS plates in fixation of these fractures. Level III.

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

    NASA Technical Reports Server (NTRS)

    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.

  12. "Character of a University": The Journey of a College President in the Early Republic

    ERIC Educational Resources Information Center

    Cousins, James P.

    2014-01-01

    Reverend Horace Holley, a New England-born, Yale-educated, Unitarian minister from Boston, was offered the presidency of Transylvania University in the town of Lexington, Kentucky, in 1817. He investigated the opportunity by way of a "tour of inquiry," a circuitous route west through notable "literary establishments" of the…

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

    ERIC Educational Resources Information Center

    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…

  14. Early Participation in the American College and University Presidents Climate Commitment

    ERIC Educational Resources Information Center

    White, Stacey Swearingen

    2009-01-01

    Purpose: The purpose of this paper is to describe and analyze those US campuses that became signatories of the American College and University Presidents Climate Commitment (ACUPCC) during the charter membership period of December 2006 through September 15, 2007. Design/methodology/approach: The paper draws on literature in organizational change,…

  15. Universal Session-Level Change Processes in an Early Session of Psychotherapy: Path Models

    ERIC Educational Resources Information Center

    Kolden, Gregory G.; Chisholm-Stockard, Sarah M.; Strauman, Timothy J.; Tierney, Sandy C.; Mullen, Elizabeth A.; Schneider, Kristin L.

    2006-01-01

    The authors used structural equation modeling to investigate universal change processes identified in the generic model of psychotherapy (GMP). Three path models of increasing complexity were examined in Study 1 in dynamic therapy. The best fitting model from Study one was replicated in Study two for participants receiving either cognitive or…

  16. Developmentally Universal Practice: Visioning Innovative Early Childhood Pedagogy for Meeting the Needs of Diverse Learners

    ERIC Educational Resources Information Center

    Harris, Kathleen I.

    2015-01-01

    Although developmentally appropriate practice (DAP) has strong merits, there are considerations pertaining to its development and implementation which must be raised. In order for educators to include diverse voices of young children, the time has come for a new conversation to unfold introducing developmentally universal practice (DUP). With this…

  17. From Early to Current Developments in Online Learning at Nova Southeastern University: Reflections on Historical Milestones.

    ERIC Educational Resources Information Center

    Dringus, Laurie P.; Scigliano, John A.

    2000-01-01

    Traces the major historical milestones achieved by Nova Southeastern University in its pioneering of graduate level online learning programs. Highlights include delivery systems; Web-based electronic classrooms; overview of the technology, including telecommunications through UNIX; evaluation and research; and technology used in the School of…

  18. Transformational Learning and Community Development: Early Reflections on Professional and Community Engagement at Macquarie University

    ERIC Educational Resources Information Center

    Rawlings-Sanaei, Felicity; Sachs, Judyth

    2014-01-01

    Professional and Community Engagement (PACE) at Macquarie University offers undergraduate students experiential learning opportunities with local, regional, and international partners. In PACE projects, students work toward meeting the partner's organizational goals while they develop their capabilities, learn through the process of engagement,…

  19. Planning for Universal Design for Learning in the Early Childhood Inclusion Classroom: A Case Study

    ERIC Educational Resources Information Center

    Stone, Jennifer

    2013-01-01

    The majority of children with exceptionalities aged 3-5 are being served in general education settings. Teachers working in these inclusion classrooms must have the ability and knowledge to work with all students under their care. The purpose of this study was to determine how teachers in early childhood inclusion classrooms plan to incorporate…

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

    ERIC Educational Resources Information Center

    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…

  1. The creation and early implementation of a high speed fiber optic network for a university health sciences center.

    PubMed Central

    Schueler, J. D.; Mitchell, J. A.; Forbes, S. M.; Neely, R. C.; Goodman, R. J.; Branson, D. K.

    1991-01-01

    In late 1989 the University of Missouri Health Sciences Center began the process of creating an extensive fiber optic network throughout its facilities, with the intent to provide networked computer access to anyone in the Center desiring such access, regardless of geographic location or organizational affiliation. A committee representing all disciplines within the Center produced and, in conjunction with independent consultants, approved a comprehensive design for the network. Installation of network backbone components commenced in the second half of 1990 and was completed in early 1991. As the network entered its initial phases of operation, the first realities of this important new resource began to manifest themselves as enhanced functional capacity in the Health Sciences Center. This paper describes the development of the network, with emphasis on its design criteria, installation, early operation, and management. Also included are discussions on its organizational impact and its evolving significance as a medical community resource. PMID:1807660

  2. Physics of the very early Universe: what can we learn from cosmological observations?

    NASA Astrophysics Data System (ADS)

    Gondolo, Paolo

    Cosmological observations are starting to probe the evolution of the Universe before nucleosyn- thesis. The observed fluctuations in the cosmic microwave background and in the distribution of matter can be traced back to their origin during inflation, and the inflaton potential has begun to be unraveled. A future probe of the first microseconds would be the detection of weakly-interacting massive particles as dark matter. Discovery of supersymmetric particles at odds with the standard cosmological lore may open an experimental window on the physics at the highest energies, per- haps as far as superstring theory. This presentation will overview two topics on the physics of the Universe before nucleosynthesis: (1) slow-roll, natural and chain inflation in the landscape, and

  3. Proton-hydrogen collisions for Rydberg n,l-changing transitions in the early Universe

    NASA Astrophysics Data System (ADS)

    Vrinceanu, Daniel

    2013-05-01

    Cosmic Microwave Background (CMB) is a vestige radiation generated during the Recombination era, some 390,000 years after the Big Bang, when the Universe had become transparent for the first time. Initial observations of CMB made by the Wilkinson Microwave Anisotropy Probe (WMAP) led to determining the age of the Universe. The mechanisms that drove the recombination have been discovered by using modeling of the primordial plasma and seeking agreement with the observations. The new Plank Surveyor Instrument launched in 2009 is expected to produce data about the recombination era of an unprecedented accuracy, that require including better information regarding the basic atomic physics processes into the present models. In this talk, I will review the results for various Rydberg atom - charge particle collisions and establish their relative importance during the stages of recombination era, with respect to each other and to radiative processes. Energy changing and angular momentum changing collisions with electrons and ions are considered. This work has been supported by NSF through grants to the Institute for Theoretical Atomic and Molecular Physics at Harvard Smithsonian Center for Astrophysics and to the Center for Research on Complex Networks at Texas Southern University.

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

    NASA Astrophysics Data System (ADS)

    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

  5. Investigating Interactions between the Silica and Carbon Cycles during Precipitation and Early Diagenesis of Authigenic Clay/Carbonate-Mineral Associations in the Carbonate Rock Record

    NASA Astrophysics Data System (ADS)

    McKenzie, J. A.; Francisca Martinez Ruiz, F.; Sanchez-Roman, M.; Anjos, S.; Bontognali, T. R. R.; Nascimento, G. S.; Vasconcelos, C.

    2017-12-01

    The study of authigenic clay/carbonate-mineral associations within carbonate sequences has important implications for the interpretation of scientific problems related with rock reservoir properties, such as alteration of potential porosity and permeability. More specifically, when clay minerals are randomly distributed within the carbonate matrix, it becomes difficult to predict reservoir characteristics. In order to understand this mineral association in the geological record, we have undertaken a comparative study of specially designed laboratory experiments with modern environments, where clay minerals have been shown to precipitate together with a range of carbonate minerals, including calcite, Mg-calcite and dolomite. Two modern dolomite-forming environments, the Coorong lakes, South Australia and Brejo do Espinho Rio de Janeiro, Brazil, were selected for this investigation. For comparative evaluation, enrichment microbial culture experiments, using natural pore water from Brejo do Espinho as the growth medium to promote mineral precipitation, were performed under both aerobic and anaerobic conditions. To establish the environmental parameters and biological processes facilitating the dual mineral association, the experimental samples have been compared with the natural minerals using HRTEM measurements. The results demonstrate that the clay and carbonate minerals apparently do not co-precipitate, but the precipitation of the different minerals in the same sample has probably occurred under different environmental conditions with variable chemistries, e.g., hypersalinity versus normal salinity resulting from the changing ratio of evaporation versus precipitation. Thus, the investigated mineral association is not a product of diagenetic processes but of sequential in situ precipitation processes related to changes in the silica and carbon availability. Implications for ancient carbonate formations will be presented and discussed in the context of a specific

  6. Importance of early season conditions and grazing on carbon dioxide fluxes in Colorado shortgrass steppe

    USDA-ARS?s Scientific Manuscript database

    Understanding the influence of environmental and management drivers on fluxes of carbon dioxide (CO2) is essential for optimizing carbon (C) uptake and storage in livestock production systems. Herein, using 15 treatment-years (two three-year experiments, one with three grazing treatments, the other ...

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

    PubMed

    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.

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

    SciTech Connect

    McCaffery, Anthony J., E-mail: A.J.McCaffery@sussex.ac.uk

    Little is known of the mechanism by which H and H{sub 2}, 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 H{sub 2}, 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 H{sub 2} in amore » 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 H{sub 2} + 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.« less

  9. Geometry in transition in four dimensions: A model of emergent geometry in the early universe

    NASA Astrophysics Data System (ADS)

    Ydri, Badis; Khaled, Ramda; Ahlam, Rouag

    2016-10-01

    We study a six matrix model with global S O (3 )×S O (3 ) symmetry containing at most quartic powers of the matrices. This theory exhibits a phase transition from a geometrical phase at low temperature to a Yang-Mills matrix phase with no background geometrical structure at high temperature. This is an exotic phase transition in the same universality class as the three matrix model but with important differences. The geometrical phase is determined dynamically, as the system cools, and is given by a fuzzy sphere background SN2×SN2, with an Abelian gauge field which is very weakly coupled to two normal scalar fields.

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

    SciTech Connect

    Dorsch, G.C.; Konstandin, T.; Huber, S.J.

    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.

  11. Power law expansion of the early universe for a V (a) = kan potential

    NASA Astrophysics Data System (ADS)

    Freitas, Augusto S.

    2018-01-01

    In a recent paper, He, Gao and Cai [Phys. Rev. D 89, 083510 (2014)], found a rigorous proof, based on analytical solutions of the Wheeler-DeWitt (WDWE) equation, of the spontaneous creation of the universe from nothing. The solutions were obtained from a classical potential V = ka2, where a is the scale factor. In this paper, we present a complementary (to that of He, Gao and Cai) solution to the WDWE equation with V = kan. I have found an exponential expansion of the true vacuum bubble for all scenarios. In all scenarios, we found a power law behavior of the scale factor result which is in agreement with another studies.

  12. Baryogenesis via dark matter-induced symmetry breaking in the early Universe

    NASA Astrophysics Data System (ADS)

    Sakstein, Jeremy; Trodden, Mark

    2017-11-01

    We put forward a new proposal for generating the baryon asymmetry of the universe by making use of the dynamics of a U (1) scalar field coupled to dark matter. High dark matter densities cause the U (1) symmetry to break spontaneously so that the field acquires a large vacuum expectation value. The symmetry is restored when the density redshifts below a critical value, resulting in the coherent oscillation of the scalar field. A net B - L number can be generated either via baryon number-conserving couplings to the standard model or through small symmetry-violating operators and the subsequent decay of the scalar condensate.

  13. Evaluation of Standardized Instruments for Use in Universal Screening of Very Early School-Age Children: Suitability, Technical Adequacy, and Usability

    ERIC Educational Resources Information Center

    Miles, Sandra; Fulbrook, Paul; Mainwaring-Mägi, Debra

    2018-01-01

    Universal screening of very early school-age children (age 4-7 years) is important for early identification of learning problems that may require enhanced learning opportunity. In this context, use of standardized instruments is critical to obtain valid, reliable, and comparable assessment outcomes. A wide variety of standardized instruments is…

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

    PubMed

    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.

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

    PubMed

    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.

  16. Early Carboniferous (Tournasian-early Visean) global paleogeography, Paleostorm tracts, and the distribution of Waulsortian and Waulsortian-like carbonate mud mounds

    SciTech Connect

    King, D.T. Jr.

    1990-05-01

    Tournasian-early Visean mud mounds (i.e., Waulsortian and Waulsortian-like mounds) are unlike other carbonate buildups in the stratigraphic record because they lack an identifiable frame-building organism. Waulsortian mounds are comprised mainly of carbonate mud; Waulsortian-like mounds are mud-rich and contain a significant percent of skeletal grains, especially crinoids and bryozoa. This study has revealed that all of the reported Waulsortian and Waulsortian-like mounds developed in low paleolatitudes either on the southern shelf margin of the Laurussian paleocontinent or in the Laurussian interior seaway. Waulsortian and Waulsortian-like mounds are specifically not present in low-latitude regions of other paleocontinents. As Tournasian-early Visean carbonatemore » deposition was widespread in the range of 30{degree}N to 10{degree}S, the very restricted paleogeographic distribution of Waulsortian and Waulsortian-like mound locations suggests a mechanism or set of conditions that effectively limited the distribution of mud mounds. Considering the Tournasian-early Visean distribution of paleocontinents and the principles that govern the movement of modern hurricanes, tropical storms, and winter storms, the tracts of hurricanes, tropical storms, and winter storms probably crossed all main submerged paleocontinental areas except the southern Laurussian shelf margin and the Laurussian interior seaway, the two areas where mud mounds developed. The lack of storm energy in these two large areas of Laurussia provided long-term stability and thus enhanced the growth prospects of the frame-deficient Waulsortian and Waulsortian-like mud mounds. Lack of extensive periodic wave reworking and other storm-induced devastation helps to account for enigmatic features such as general mound symmetry, great size, high depositional relief (as much as 220 m), and side steepness (as steep as 50{degree}).« less

  17. Gone with the heat: a fundamental constraint on the imaging of dust and molecular gas in the early Universe.

    PubMed

    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.

  18. Gone with the heat: a fundamental constraint on the imaging of dust and molecular gas in the early Universe

    PubMed Central

    Zhang, Zhi-Yu; Smith, M. W. L.; Xilouris, Emmanuel M.

    2016-01-01

    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. PMID:27429763

  19. Cool episode and platform demise in the Early Aptian: New insights on the links between climate and carbonate production

    NASA Astrophysics Data System (ADS)

    Bonin, Aurélie; Pucéat, Emmanuelle; Vennin, Emmanuelle; Mattioli, Emanuela; Aurell, Marcos; Joachimski, Michael; Barbarin, Nicolas; Laffont, Rémi

    2016-01-01

    The Early Aptian encountered several crises in neritic and pelagic carbonate production, major perturbations in the carbon cycle, and an oceanic anoxic event (OAE1a). Yet the causal links between these perturbations and climate changes remain poorly understood, partly because temperature records spanning the Early Aptian interval are still scant. We present new δ18O data from well-preserved bivalves from a carbonate platform of the Galve subbasin (Spain) that document a major cooling event postdating most of OAE1a. Our data show that cooling postdates the global platform demise and cannot have triggered this event that occurred during the warmest interval. The warmest temperatures coincide with the time equivalent of OAE1a and with platform biotic assemblages dominated by microbialites at Aliaga as well as on other Tethyan platforms. Coral-dominated assemblages then replace microbialites during the subsequent cooling. Nannoconids are absent during most of the time equivalent of the OAE1a, probably related to the well-known crisis affecting this group. Yet they present a transient recovery in the upper part of this interval with an increase in both size and abundance during the cool interval portion that postdates OAE1a. An evolution toward cooler and drier climatic conditions may have induced the regional change from microbial to coral assemblages as well as nannoconids size and abundance increase by limiting continent-derived input of nutrients.

  20. Basanite-nephelinite suite from early Kilauea: Carbonated melts of phlogopite-garnet peridotite at Hawaii's leading magmatic edge

    USGS Publications Warehouse

    Sisson, T.W.; Kimura, Jun-Ichi; Coombs, M.L.

    2009-01-01

    A basanite-nephelinite glass suite from early submarine Kilauea defines a continuous compositional array marked by increasing concentrations of incompatible components with decreasing SiO2, MgO, and Al2O3. Like peripheral and post-shield strongly alkalic Hawaiian localities (Clague et al. in J Volcanol Geotherm Res 151:279-307, 2006; Dixon et al. in J Pet 38:911-939, 1997), the early Kilauea basanite-nephelinite glasses are interpreted as olivine fractionation products from primary magnesian alkalic liquids. For early Kilauea, these were saturated with a garnet-phlogopite-sulfide peridotite assemblage, with elevated dissolved CO2 contents responsible for the liquids' distinctly low-SiO2 concentrations. Reconstructed primitive liquids for early Kilauea and other Hawaiian strongly alkalic localities are similar to experimental 3 GPa low-degree melts of moderately carbonated garnet lherzolite, and estimated parent magma temperatures of 1,350-1,400??C (olivine-liquid geothermometry) match the ambient upper mantle geotherm shortly beneath the base of the lithosphere. The ???3 GPa source regions were too hot for stable crystalline carbonate and may have consisted of ambient upper mantle peridotite containing interstitial carbonate-silicate or carbonatitic liquid, possibly (Dixon et al. in Geochem Geophys Geosyst 9(9):Q09005, 2008), although not necessarily, from the Hawaiian mantle plume. Carbonate-enriched domains were particularly susceptible to further melting upon modest decompression during upward lithospheric flexure beneath the advancing Hawaiian Arch, or by conductive heating or upward drag by the Hawaiian mantle plume. The early Kilauea basanite-nephelinite suite has a HIMU-influenced isotopic character unlike other Hawaiian magmas (Shimizu et al. in EOS Tran Amer Geophys Union 82(47): abstr V12B-0962, 2001; Shimizu et al. in Geochim Cosmochim Acta 66(15A):710, 2002) but consistent with oceanic carbonatite involvement (Hoernle et al. in Contrib Mineral Petrol

  1. Basanite-nephelinite suite from early Kilauea: carbonated melts of phlogopite-garnet peridotite at Hawaii's leading magmatic edge

    NASA Astrophysics Data System (ADS)

    Sisson, T. W.; Kimura, J.-I.; Coombs, M. L.

    2009-12-01

    A basanite-nephelinite glass suite from early submarine Kilauea defines a continuous compositional array marked by increasing concentrations of incompatible components with decreasing SiO2, MgO, and Al2O3. Like peripheral and post-shield strongly alkalic Hawaiian localities (Clague et al. in J Volcanol Geotherm Res 151:279-307, 2006; Dixon et al. in J Pet 38:911-939, 1997), the early Kilauea basanite-nephelinite glasses are interpreted as olivine fractionation products from primary magnesian alkalic liquids. For early Kilauea, these were saturated with a garnet-phlogopite-sulfide peridotite assemblage, with elevated dissolved CO2 contents responsible for the liquids’ distinctly low-SiO2 concentrations. Reconstructed primitive liquids for early Kilauea and other Hawaiian strongly alkalic localities are similar to experimental 3 GPa low-degree melts of moderately carbonated garnet lherzolite, and estimated parent magma temperatures of 1,350-1,400°C (olivine-liquid geothermometry) match the ambient upper mantle geotherm shortly beneath the base of the lithosphere. The ~3 GPa source regions were too hot for stable crystalline carbonate and may have consisted of ambient upper mantle peridotite containing interstitial carbonate-silicate or carbonatitic liquid, possibly (Dixon et al. in Geochem Geophys Geosyst 9(9):Q09005, 2008), although not necessarily, from the Hawaiian mantle plume. Carbonate-enriched domains were particularly susceptible to further melting upon modest decompression during upward lithospheric flexure beneath the advancing Hawaiian Arch, or by conductive heating or upward drag by the Hawaiian mantle plume. The early Kilauea basanite-nephelinite suite has a HIMU-influenced isotopic character unlike other Hawaiian magmas (Shimizu et al. in EOS Tran Amer Geophys Union 82(47): abstr V12B-0962, 2001; Shimizu et al. in Geochim Cosmochim Acta 66(15A):710, 2002) but consistent with oceanic carbonatite involvement (Hoernle et al. in Contrib Mineral Petrol

  2. Towards a universal microbial inoculum for dissolved organic carbon degradation experiments

    NASA Astrophysics Data System (ADS)

    Pastor, Ada; Catalán, Núria; Gutiérrez, Carmen; Nagar, Nupur; Casas-Ruiz, Joan P.; Obrador, Biel; von Schiller, Daniel; Sabater, Sergi; Petrovic, Mira; Borrego, Carles M.; Marcé, Rafael

    2017-04-01

    Dissolved organic carbon (DOC) is the largest biologically available pool of organic carbon in aquatic ecosystems and its degradation along the land-to-ocean continuum has implications for carbon cycling from local to global scales. DOC biodegradability is usually assessed by incubating filtered water inoculated with native microbial assemblages in the laboratory. However, the use of a native inoculum from several freshwaters, without having a microbial-tailored design, hampers our ability to tease apart the relative contribution of the factors driving DOC degradation from the effects of local microbial communities. The use of a standard microbial inoculum would allow researchers to disentangle the drivers of DOC degradation from the metabolic capabilities of microbial communities operating in situ. With this purpose, we designed a bacterial inoculum to be used in experiments of DOC degradation in freshwater habitats. The inoculum is composed of six bacterial strains that easily grow under laboratory conditions, possess a versatile metabolism and are able to grow under both aerobic and anaerobic conditions. The mixed inoculum showed higher DOC degradation rates than those from their isolated bacterial components and the consumption of organic substrates was consistently replicated. Moreover, DOC degradation rates obtained using the designed inoculum were responsive across a wide range of natural water types differing in DOC concentration and composition. Overall, our results show the potential of the designed inoculum as a tool to discriminate between the effects of environmental drivers and intrinsic properties of DOC on degradation dynamics.

  3. Analysis and Characterization of Organic Carbon in Early Holocene Wetland Paleosols using Ramped Pyrolysis 14C and Biomarkers

    NASA Astrophysics Data System (ADS)

    Vetter, L.; Schreiner, K. M.; Fernandez, A.; Rosenheim, B. E.; Tornqvist, T. E.

    2014-12-01

    Radiocarbon analyses are a key tool for quantifying the dynamics of carbon cycling and storage in both modern soils and Quaternary paleosols. Frequently, bulk 14C dates of paleosol organic carbon provide ages older than the time of soil burial, and 14C dates of geochemical fractions such as alkali and acid extracts (operationally defined as humic acids) can provide anomalously old ages when compared to coeval plant macrofossil dates. Ramped pyrolysis radiocarbon analysis of sedimentary organic material has been employed as a tool for investigating 14C age spectra in sediments with multiple organic carbon sources. Here we combine ramped pyrolysis 14C analysis and biomarker analysis (lignin-phenols and other cupric oxide products) to provide information on the source and diagenetic state of the paleosol organic carbon. We apply these techniques to immature early Holocene brackish wetland entisols from three sediment cores in southeastern Louisiana, along with overlying basal peats. Surprisingly, we find narrow 14C age spectra across all thermal aliquots from both paleosols and peats. The weighted bulk 14C ages from paleosols and overlying peats are within analytical error, and are comparable to independently analyzed 14C AMS dates from charcoal fragments and other plant macrofossils from each peat bed. Our results suggest high turnover rates of carbon in soils relative to input of exogenous carbon sources. These data raise broader questions about processes within the active soil and during pedogenesis and burial of paleosols that can effectively homogenize radiocarbon content in soils across the thermochemical spectrum. The concurrence of paleosol and peat 14C ages also suggests that, in the absence of peats with identifiable plant macrofossils, ramped pyrolysis 14C analyses of paleosols may be used to provide ages for sea-level indicators.

  4. The impact of deep-tier burrow systems in sediment mixing and ecosystem engineering in early Cambrian carbonate settings

    PubMed Central

    Zhang, Li-Jun; Qi, Yong-An; Buatois, Luis A.; Mángano, M. Gabriela; Meng, Yao; Li, Da

    2017-01-01

    Bioturbation plays a substantial role in sediment oxygen concentration, chemical cycling, regeneration of nutrients, microbial activity, and the rate of organic matter decomposition in modern oceans. In addition, bioturbators are ecosystem engineers which promote the presence of some organisms, while precluding others. However, the impact of bioturbation in deep time remains controversial and limited sediment mixing has been indicated for early Paleozoic seas. Our understanding of the actual impact of bioturbation early in the Phanerozoic has been hampered by the lack of detailed analysis of the functional significance of specific burrow architectures. Integration of ichnologic and sedimentologic evidence from North China shows that deep-tier Thalassinoides mazes occur in lower Cambrian nearshore carbonate sediments, leading to intense disruption of the primary fabric. Comparison with modern studies suggest that some of the effects of this style of Cambrian bioturbation may have included promotion of nitrogen and ammonium fluxes across the sediment-water interface, average deepening of the redox discontinuity surface, expansion of aerobic bacteria, and increase in the rate of organic matter decomposition and the regeneration of nutrients. Our study suggests that early Cambrian sediment mixing in carbonate settings may have been more significant than assumed in previous models. PMID:28374857

  5. Variables associated with the risk of early death after liver transplantation at a liver transplant unit in a university hospital.

    PubMed

    Azevedo, L D; Stucchi, R S; de Ataíde, E C; Boin, I F S F

    2015-05-01

    Graft dysfunction after liver transplantation is a serious complication that can lead to graft loss and patient death. This was a study to identify risk factors for early death (up to 30 days after transplantation). It was an observational and retrospective analysis at the Liver Transplantation Unit, Hospital de Clinicas, State University of Campinas, Brazil. From July 1994 to December 2012, 302 patients were included (>18 years old, piggyback technique). Of these cases, 26% died within 30 days. For analysis, Student t tests and chi-square were used to analyze receptor-related (age, body mass index, serum sodium, graft dysfunction, Model for End-Stage Liver Disease score, renal function, and early graft dysfunction [EGD type 1, 2, or 3]), surgery (hot and cold ischemia, surgical time, and units of packed erythrocytes [pRBC]), and donor (age, hypotension, and brain death cause) factors. Risk factors were identified by means of logistic regression model adjusted by the Hosmer-Lemeshow test with significance set at P < .05. We found that hyponatremic recipients had a 6.26-fold higher risk for early death. There was a 9% reduced chance of death when the recipient serum sodium increased 1 unit. The chance of EGD3 to have early death was 18-fold higher than for EGD1 and there was a 13% increased risk for death for each unit of pRBC transfused. Donor total bilirubin, hyponatremia, massive transfusion, and EGD3 in the allocation graft should be observed for better results in the postoperative period. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. A Possible Late Paleocene-Early Eocene Ocean Acidification Event Recoded in the Adriatic Carbonate Platform

    NASA Astrophysics Data System (ADS)

    Weiss, A.; Martindale, R. C.; Kosir, A.; Oefinger, J.

    2017-12-01

    The Paleocene-Eocene Thermal Maximum (PETM) event ( 56.3 Ma) was a period of massive carbon release into the Earth system, resulting in significant shifts in ocean chemistry. It has been proposed that ocean acidification - a decrease in the pH and carbonate saturation state of the water as a result of dissolved carbon dioxide in sea water - occurred in both the shallow and deep marine realms. Ocean acidification would have had a devastating impact on the benthic ecosystem, and has been proposed as the cause of decreased carbonate deposition in marine sections and coral reef collapse during the late Paleocene. To date, however, the only physical evidence of Paleocene-Eocene ocean acidification has been shown for offshore sites (i.e., a shallow carbonate compensation depth), but isotope analysis (i.e. B, I/Ca) suggests that acidification occurred in the shallow shelves as well. Several sites in the Kras region of Slovenia, has been found to contain apparent erosion surfaces coeval with the Paleocene-Eocene Boundary. We have investigated these potentially acidified horizons using petrography, stable carbon isotopes, cathodoluminescence, and elemental mapping. These datasets will inform whether the horizons formed by seafloor dissolution in an acidified ocean, or are due to subaerial exposure, or burial diagenesis (i.e. stylotization). Physical erosion and diagenesis can easily be ruled out based on field relationships and petrography, but the other potential causes must be analyzed more critically.

  7. Relevance of early head CT scans following neurosurgical procedures: an analysis of 892 intracranial procedures at Rush University Medical Center.

    PubMed

    Fontes, Ricardo B V; Smith, Adam P; Muñoz, Lorenzo F; Byrne, Richard W; Traynelis, Vincent C

    2014-08-01

    Early postoperative head CT scanning is routinely performed following intracranial procedures for detection of complications, but its real value remains uncertain: so-called abnormal results are frequently found, but active, emergency intervention based on these findings may be rare. The authors' objective was to analyze whether early postoperative CT scans led to emergency surgical interventions and if the results of neurological examination predicted this occurrence. The authors retrospectively analyzed 892 intracranial procedures followed by an early postoperative CT scan performed over a 1-year period at Rush University Medical Center and classified these cases according to postoperative neurological status: baseline, predicted neurological change, unexpected neurological change, and sedated or comatose. The interpretation of CT results was reviewed and unexpected CT findings were classified based on immediate action taken: Type I, additional observation and CT; Type II, active nonsurgical intervention; and Type III, surgical intervention. Results were compared between neurological examination groups with the Fisher exact test. Patients with unexpected neurological changes or in the sedated or comatose group had significantly more unexpected findings on the postoperative CT (p < 0.001; OR 19.2 and 2.3, respectively) and Type II/III interventions (p < 0.001) than patients at baseline. Patients at baseline or with expected neurological changes still had a rate of Type II/III changes in the 2.2%-2.4% range; however, no patient required an immediate return to the operating room. Over a 1-year period in an academic neurosurgery service, no patient who was neurologically intact or who had a predicted neurological change required an immediate return to the operating room based on early postoperative CT findings. Obtaining early CT scans should not be a priority in these patients and may even be cancelled in favor of MRI studies, if the latter have already been planned

  8. Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model

    NASA Astrophysics Data System (ADS)

    Krissansen-Totton, Joshua; Arney, Giada N.; Catling, David C.

    2018-04-01

    The early Earth’s environment is controversial. Climatic estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early climate and ocean chemistry would improve our knowledge of the origin of life and its coevolution with the environment. Here, we use a geological carbon cycle model with ocean chemistry to calculate self-consistent histories of climate and ocean pH. Our carbon cycle model includes an empirically justified temperature and pH dependence of seafloor weathering, allowing the relative importance of continental and seafloor weathering to be evaluated. We find that the Archean climate was likely temperate (0–50 °C) due to the combined negative feedbacks of continental and seafloor weathering. Ocean pH evolves monotonically from 6.6‑0.4+0.6 (2σ) at 4.0 Ga to 7.0‑0.5+0.7 (2σ) at the Archean–Proterozoic boundary, and to 7.9‑0.2+0.1 (2σ) at the Proterozoic–Phanerozoic boundary. This evolution is driven by the secular decline of pCO2, which in turn is a consequence of increasing solar luminosity, but is moderated by carbonate alkalinity delivered from continental and seafloor weathering. Archean seafloor weathering may have been a comparable carbon sink to continental weathering, but is less dominant than previously assumed, and would not have induced global glaciation. We show how these conclusions are robust to a wide range of scenarios for continental growth, internal heat flow evolution and outgassing history, greenhouse gas abundances, and changes in the biotic enhancement of weathering.

  9. Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model.

    PubMed

    Krissansen-Totton, Joshua; Arney, Giada N; Catling, David C

    2018-04-17

    The early Earth's environment is controversial. Climatic estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early climate and ocean chemistry would improve our knowledge of the origin of life and its coevolution with the environment. Here, we use a geological carbon cycle model with ocean chemistry to calculate self-consistent histories of climate and ocean pH. Our carbon cycle model includes an empirically justified temperature and pH dependence of seafloor weathering, allowing the relative importance of continental and seafloor weathering to be evaluated. We find that the Archean climate was likely temperate (0-50 °C) due to the combined negative feedbacks of continental and seafloor weathering. Ocean pH evolves monotonically from [Formula: see text] (2σ) at 4.0 Ga to [Formula: see text] (2σ) at the Archean-Proterozoic boundary, and to [Formula: see text] (2σ) at the Proterozoic-Phanerozoic boundary. This evolution is driven by the secular decline of pCO 2 , which in turn is a consequence of increasing solar luminosity, but is moderated by carbonate alkalinity delivered from continental and seafloor weathering. Archean seafloor weathering may have been a comparable carbon sink to continental weathering, but is less dominant than previously assumed, and would not have induced global glaciation. We show how these conclusions are robust to a wide range of scenarios for continental growth, internal heat flow evolution and outgassing history, greenhouse gas abundances, and changes in the biotic enhancement of weathering. Copyright © 2018 the Author(s). Published by PNAS.

  10. Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model

    PubMed Central

    Krissansen-Totton, Joshua; Arney, Giada N.

    2018-01-01

    The early Earth’s environment is controversial. Climatic estimates range from hot to glacial, and inferred marine pH spans strongly alkaline to acidic. Better understanding of early climate and ocean chemistry would improve our knowledge of the origin of life and its coevolution with the environment. Here, we use a geological carbon cycle model with ocean chemistry to calculate self-consistent histories of climate and ocean pH. Our carbon cycle model includes an empirically justified temperature and pH dependence of seafloor weathering, allowing the relative importance of continental and seafloor weathering to be evaluated. We find that the Archean climate was likely temperate (0–50 °C) due to the combined negative feedbacks of continental and seafloor weathering. Ocean pH evolves monotonically from 6.6−0.4+0.6 (2σ) at 4.0 Ga to 7.0−0.5+0.7 (2σ) at the Archean–Proterozoic boundary, and to 7.9−0.2+0.1 (2σ) at the Proterozoic–Phanerozoic boundary. This evolution is driven by the secular decline of pCO2, which in turn is a consequence of increasing solar luminosity, but is moderated by carbonate alkalinity delivered from continental and seafloor weathering. Archean seafloor weathering may have been a comparable carbon sink to continental weathering, but is less dominant than previously assumed, and would not have induced global glaciation. We show how these conclusions are robust to a wide range of scenarios for continental growth, internal heat flow evolution and outgassing history, greenhouse gas abundances, and changes in the biotic enhancement of weathering. PMID:29610313

  11. Application of carbon nanoparticles in laparoscopic sentinel lymph node detection in patients with early-stage cervical cancer.

    PubMed

    Lu, Yan; Wei, Jin-Ying; Yao, De-Sheng; Pan, Zhong-Mian; Yao, Yao

    2017-01-01

    To investigate the value of carbon nanoparticles in identifying sentinel lymph nodes in early-stage cervical cancer. From January 2014 to January 2016, 40 patients with cervical cancer stage IA2-IIA, based on the International Federation of Gynecology and Obstetrics (FIGO) 2009 criteria, were included in this study. The normal cervix around the tumor was injected with a total of 1 mL of carbon nanoparticles (CNP)at 3 and 9 o'clock. All patients then underwent laparoscopic pelvic lymph node dissection and radical hysterectomy. The black-dyed sentinel lymph nodes were removed for routine pathological examination and immunohistochemical staining. Among the 40 patients, 38 patients had at least one sentinel lymph node (SLN). The detection rate was 95% (38/40). One hundred seventy-three SLNs were detected with an average of 3.9 SLNs per side. 25 positive lymph nodes, which included 21 positive SLNs, were detected in 8 (20%) patients. Sentinel lymph nodes were localized in the obturator (47.97%), internal lilac (13.87%), external lilac (26.59%), parametrial (1.16%), and common iliac (8.67%) regions. The sensitivity of the SLN detection was 100% (5/5), the accuracy was 97.37% (37/38), and the negative predictive value was 100. 0% and the false negative rate was 0%. Sentinel lymph nodes can be used to accurately predict the pathological state of pelvic lymph nodes in early cervical cancer. The detection rates and accuracy of sentinel lymph node were high. Carbon nanoparticles can be used to trace the sentinel lymph node in early cervical cancer.

  12. Earth-mass dark-matter haloes as the first structures in the early Universe.

    PubMed

    Diemand, J; Moore, B; Stadel, J

    2005-01-27

    The Universe was nearly smooth and homogeneous before a redshift of z = 100, about 20 million years after the Big Bang. After this epoch, the tiny fluctuations imprinted upon the matter distribution during the initial expansion began to collapse because of gravity. The properties of these fluctuations depend on the unknown nature of dark matter, the determination of which is one of the biggest challenges in present-day science. Here we report supercomputer simulations of the concordance cosmological model, which assumes neutralino dark matter (at present the preferred candidate), and find that the first objects to form are numerous Earth-mass dark-matter haloes about as large as the Solar System. They are stable against gravitational disruption, even within the central regions of the Milky Way. We expect over 10(15) to survive within the Galactic halo, with one passing through the Solar System every few thousand years. The nearest structures should be among the brightest sources of gamma-rays (from particle-particle annihilation).

  13. A new insight into the phase transition in the early Universe with two Higgs doublets

    NASA Astrophysics Data System (ADS)

    Bernon, Jérémy; Bian, Ligong; Jiang, Yun

    2018-05-01

    We study the electroweak phase transition in the alignment limit of the CP-conserving two-Higgs-doublet model (2HDM) of Type I and Type II. The effective potential is evaluated at one-loop, where the thermal potential includes Daisy corrections and is reliably approximated by means of a sum of Bessel functions. Both 1-stage and 2-stage electroweak phase transitions are shown to be possible, depending on the pattern of the vacuum development as the Universe cools down. For the 1-stage case focused on in this paper, we analyze the properties of phase transition and discover that the field value of the electroweak symmetry breaking vacuum at the critical temperature at which the first order phase transition occurs is largely correlated with the vacuum depth of the 1-loop potential at zero temperature. We demonstrate that a strong first order electroweak phase transition (SFOEWPT) in the 2HDM is achievable and establish benchmark scenarios leading to different testable signatures at colliders. In addition, we verify that an enhanced triple Higgs coupling (including loop corrections) is a typical feature of the SFOPT driven by the additional doublet. As a result, SFOEWPT might be able to be probed at the LHC and future lepton colliders through Higgs pair production.

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

    PubMed

    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.

  15. The characteristic black hole mass resulting from direct collapse in the early Universe

    NASA Astrophysics Data System (ADS)

    Latif, M. A.; Schleicher, D. R. G.; Schmidt, W.; Niemeyer, J. C.

    2013-12-01

    Black holes of a billion solar masses are observed in the infant Universe a few hundred million years after the big bang. The direct collapse of protogalactic gas clouds in primordial haloes with Tvir ≥ 104 K provides the most promising way to assemble massive black holes. In this study, we aim to determine the characteristic mass scale of seed black holes and the time evolution of the accretion rates resulting from the direct collapse model. We explore the formation of supermassive black holes via cosmological large eddy simulations (LES) by employing sink particles and following their evolution for 20 000 yr after the formation of the first sink. As the resulting protostars were shown to have cool atmospheres in the presence of strong accretion, we assume here that UV feedback is negligible during this calculation. We confirm this result in a comparison run without sinks. Our findings show that black hole seeds with characteristic mass of 105 M⊙ are formed in the presence of strong Lyman-Werner flux which leads to an isothermal collapse. The characteristic mass is about two times higher in LES compared to the implicit large eddy simulations. The accretion rates increase with time and reach a maximum value of 10 M⊙ yr-1 after 104 yr. Our results show that the direct collapse model is clearly feasible as it provides the expected mass of the seed black holes.

  16. Probing Cosmic Dust of the Early Universe through High-Redshift Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Liang, S. L.; Li, Aigen

    2009-01-01

    We explore the extinction properties of the dust in the distant universe through the afterglows of high-redshifted gamma-ray bursts (GRBs) based on the "Drude" model which, unlike previous studies, does not require a prior assumption of template extinction laws. We select GRB 070802 at z ≈ 2.45 (which shows clear evidence for the 2175 Å extinction bump) and GRB 050904 at z ≈ 6.29, the second most distant GRB observed to date. We fit their afterglow spectra to determine the extinction of their host galaxies. We find that (1) their extinction curves differ substantially from that of the Milky Way and the Small and Large Magellanic Clouds (which were widely adopted as template extinction laws in the literature); (2) the 2175 Å extinction feature appears to be also present in GRB 050904 at z ≈ 6.29; and (3) there does not appear to be strong evidence for the dependence of dust extinction on redshifts. The inferred extinction curves are closely reproduced in terms of a mixture of amorphous silicate and graphite, both of which are expected supernova condensates and have been identified in primitive meteorites as presolar grains originating from supernovae (which are considered as the main source of dust at high-z).

  17. Early gas stripping as the origin of the darkest galaxies in the Universe.

    PubMed

    Mayer, L; Kazantzidis, S; Mastropietro, C; Wadsley, J

    2007-02-15

    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.

  18. [CII] At 1 < z < 2: Observing Star Formation in the Early Universe with Zeus (1 and 2)

    NASA Technical Reports Server (NTRS)

    Ferkinhoff, Carl; Hailey-Dunsheath, S.; Nikola, T.; Oberst, T.; Parshley, S.; Stacey, G.; Benford, D.; staguhn, J.

    2010-01-01

    We report the detection of the [CII] 158 micron fine structure line from six submillimeter galaxies with redshifts between 1.12 and 1.73. This more than doubles the total number of [CII] 158 micron detections reported from high redshift sources. These observations were made with the Redshift(z) and Early Universe Spectrometer(ZEUS) at the Caltech Submillimeter Observatory on Mauna Kea, Hawaii between December 2006 and March 2009. ZEUS is a background limited submm echelle grating spectrometer (Hailey-Dunsheath 2009). Currently we are constructing ZEUS-2. This new instrument will utilize the same grating but will feature a two dimensional transition-edge sensed bolometer array with SQUID multiplexing readout system enabling simultaneous background limited observations in the 200, 340,450 and 650 micron telluric windows. ZEUS-2 will allow for long slit imaging spectroscopy in nearby galaxies and a [CII] survey from z 0.25 to 2.5.

  19. Two superluminous supernovae from the early universe discovered by the supernova legacy survey

    SciTech Connect

    Howell, D. A.; Kasen, D.; Lidman, C.

    2013-12-20

    We present spectra and light curves of SNLS 06D4eu and SNLS 07D2bv, two hydrogen-free superluminous supernovae (SNe) discovered by the Supernova Legacy Survey. At z = 1.588, SNLS 06D4eu is the highest redshift superluminous SN with a spectrum, at M{sub U} = –22.7 it is one of the most luminous SNe ever observed, and it gives a rare glimpse into the rest-frame ultraviolet where these SNe put out their peak energy. SNLS 07D2bv does not have a host galaxy redshift, but on the basis of the SN spectrum, we estimate it to be at z ∼ 1.5. Both SNe havemore » similar observer-frame griz light curves, which map to rest-frame light curves in the U band and UV, rising in ∼20 rest-frame days or longer and declining over a similar timescale. The light curves peak in the shortest wavelengths first, consistent with an expanding blackbody starting near 15,000 K and steadily declining in temperature. We compare the spectra with theoretical models, and we identify lines of C II, C III, Fe III, and Mg II in the spectra of SNLS 06D4eu and SCP 06F6 and find that they are consistent with an expanding explosion of only a few solar masses of carbon, oxygen, and other trace metals. Thus, the progenitors appear to be related to those suspected for SNe Ic. A high kinetic energy, 10{sup 52} erg, is also favored. Normal mechanisms of powering core-collapse or thermonuclear SNe do not seem to work for these SNe. We consider models powered by {sup 56}Ni decay and interaction with circumstellar material, but we find that the creation and spin-down of a magnetar with a period of 2 ms, a magnetic field of 2 × 10{sup 14} G, and a 3 M {sub ☉} progenitor provides the best fit to the data.« less

  20. Introducing CoDa (Cosmic Dawn): Radiation-Hydrodynamics of Galaxy Formation in the Early Universe

    NASA Astrophysics Data System (ADS)

    Ocvirk, Pierre; Gillet, Nicolas; Shapiro, Paul; Aubert, Dominique; Iliev, Ilian; Romain, Teyssier; Yepes, Gustavo; Choi, Jun-hwan; Sullivan, David; Knebe, Alexander; Gottloeber, Stefan; D'Aloisio, Anson; Park, Hyunbae; Hoffman, Yehuda

    2015-08-01

    CoDa (Cosmic Dawn) is the largest fully coupled radiation hydrodynamics simulation of the reionization of the local Universe to date. It was performed using RAMSES-CUDATON running on 8192 nodes (i.e. 8192 GPUs) on the titan supercomputer at Oak Ridge National Laboratory to simulate a 64 h-1Mpc side box down to z=4.23. In this simulation, reionization proceeds self-consistently, driven by stellar radiation. We compare the simulation's reionization history, ionizing flux density, the cosmic star formation history and the CMB Thompson scattering optical depth with their observational values. Luminosity functions are also in rather good agreement with high redshift observations, although very bright objects (MAB1600 < -21) are overabundant in CoDa. We investigate the evolution of the intergalactic medium, and find that gas filaments present a sheathed structure, with a hot envelope surrounding a cooler core. They are however not able to self-shield, while regions denser than 10^-4.5 H atoms per comoving h^-3cm^3 are. Haloes below M ˜ 3.10^9 M⊙ are severely affected by the expanding, rising UV background: their ISM is quickly photo-heated to temperatures above our star formation threshold and therefore stop forming stars after local reionization has occured. Overall, the haloes between 10^(10-11) M⊙ dominate the star formation budget of the box for most of the Epoch of Reionization. Several additional studies will follow, looking for instance at environmental effects on galaxy properties, and the regimes of accretion.

  1. PKS 0537-286, carrying the information of the environment of SMBHs in the early Universe

    NASA Astrophysics Data System (ADS)

    Bottacini, E.; Ajello, M.; Greiner, J.; Pian, E.; Rau, A.; Palazzi, E.; Covino, S.; Ghisellini, G.; Krühler, T.; Küpcü Yoldaş, A.; Cappelluti, N.; Afonso, P.

    2010-01-01

    Context. The high-redshift (z = 3.1) blazar PKS 0537-286, belonging to the flat spectrum radio quasar blazar subclass, is one of the most luminous active galactic nuclei (AGN) in the Universe. Blazars are very suitable candidates for multiwavelength observations. Indeed, the relativistic beaming effect at work within the jet enhances their luminosity. This in turn allows the properties of the extragalactic jets, the powering central engine, and the surrounding environment to be derived. Aims: Our aim is to present the results of a multifrequency campaign from the near-IR to hard X-ray energies on PKS 0537-286 and give insight into the physical environment where the radiation processes take place. Methods: We observed the source at different epochs from 2006 to 2008 with INTEGRAL and Swift, and nearly simultaneously with ground-based optical telescopes. We also analyzed two archival spectra taken with XMM-Newton in 1999 and 2005. A comparative analysis of the results is performed. Results: The X-ray continuum of the blazar, as sampled by XMM, is described by a power law of index Γ = 1.2, modified by variable absorption at the soft X-rays, as found in other high-redshift QSOs. Modest X-ray continuum variability is found in the Swift observations. The combined Swift/BAT and Swift/XRT spectrum is very hard (Γ = 1.3). This, together with the non simultaneous EGRET detection and the more recent non detection by Fermi-LAT, constrains the peak of the high-energy component robustly. The optical/UV data, heavily affected by intervening Ly α absorption, indicate the presence of a bright thermal accretion disk that decreased in luminosity between 2006 and 2008. We infer from this a reduction of the BLR radius. When taking this into account, the 2006 and 2008 SEDs are compatible with a model based on synchrotron radiation and external inverse Compton scattering where the accretion-disk luminosity decreases between the 2 epochs by a factor 2, while the bulk Lorentz factor

  2. Low-Energy Mutual Neutralization Studies for Early Universe Hydrogen Chemistry

    NASA Astrophysics Data System (ADS)

    Urbain, Xavier

    2010-03-01

    Low-energy interactions between light ions, as they occur in low density plasmas, are ideally studied under merged-beam conditions. This was the motivation for building the dual-source setup in operation at UCL, Louvain-la-Neuve, since the early eighties. Although initially developed for the study of charge exchange [1], mutual neutralization and transfer ionization, this machine has produced a host of total cross section measurements for a wide variety of associative ionization and other reactive processes involving charged reactants, from H^+ to CO^+, in collision with H^-, D^-, C^- and O^- [2]. A recent paper by Glover et al. [3] has revived the interest for mutual neutralization studies, by stressing the need of the astrophysical community for a precise determination of the low-energy cross section of the H^+/H^- reaction. The mutual neutralization acts as a sink for negative ions which otherwise dominate the primordial formation of H2 by associative detachment with ground state H. Absolute measurements in the range 5 meV to 5 eV are needed to rule out earlier experimental work [4] contradicting the most recent theoretical predictions [5]. Our setup is currently modified to incorporate coincident imaging techniques, giving access to differential cross sections besides the branching among accessible neutral channels. Mutual neutralization reactions of H^- with H2^+ and H3^+ will also be investigated, for the role they play in laboratory plasmas [6].[4pt] [1] S. Sz"ucs, M. Karemera, M. Terao, and F. Brouillard, J. Phys. B 17, 1613 (1983).[0pt] [2] E. A. Naji et al., J. Phys. B 31, 4887 (1998), A. Le Padellec et al., J. Chem. Phys., 124, 154304 (2006) and references therein.[0pt] [3] S. C. Glover, D. W. Savin, and A.-K. Jappsen , Astrophys. J. 640, 553 (2006). [0pt] [4] J. Moseley, W. Aberth, and J. R. Peterson, Phys. Rev. Lett. 24, 435 (1970).[0pt] [5] M. Stenrup, å. Larson, and N. Elander, Phys. Rev. A 79, 012713 (2009).[0pt] [6] M. J. J. Eerden et al., Phys

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

    PubMed

    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.

  4. The ZEUS 1 & 2 INvestigated Galaxy Reference Sample (ZINGRS): A window into galaxies in the early Universe.

    NASA Astrophysics Data System (ADS)

    Ferkinhoff, Carl; Hershey, Deborah; Scrabeck, Alex; Higdon, Sarah; Higdon, James L.; Tidwell, Hannah; Lamarche, Cody; Vishwas, Amit; Nikola, Thomas; Stacey, Gordon J.; Brisbin, Drew

    2018-06-01

    Galaxies have evolved significantly from the early Universe until today. Star formation rates, stellar and molecular gas masses, sizes and metal enrichment of galaxies have all changed significantly from early epochs until the present. Probing the physical conditions of galaxy at high redshift is vital to understanding this evolution. ZINGRS, the ZEUS 1 and 2 INvestigated Galaxy Reference Sample, provides a unique and powerful window for this work. The sample consists of more than ~30 galaxies from z ~ 1 - 4.5 for which the far-IR fine-structure lines (e.g. [CII] 158 micron, [NII] 122micron, [OIII] 88 micron) have been observed with the ZEUS-1 and 2 instruments. These lines are ideal for studying high-z systems since they require low energies for excitation, are typically optically thin, and are not susceptible to extinction from dust. ZINGRS is the largest collection of far-IR fine-structure line detections at high-z. Here we describe the sample, including extensive multifrequency supporting observations like CO & radio continuum, and summarize what we have learned so far.

  5. Tempo and scale of late Paleocene and early Eocene carbon isotope cycles: Implications for the origin of hyperthermals

    NASA Astrophysics Data System (ADS)

    Zachos, James C.; McCarren, Heather; Murphy, Brandon; Röhl, Ursula; Westerhold, Thomas

    2010-10-01

    The upper Paleocene and lower Eocene are marked by several prominent (> 1‰) carbon isotope (δ 13C) excursions (CIE) that coincide with transient global warmings, or thermal maxima, including the Paleocene-Eocene Thermal Maximum (PETM). The CIE, which are recorded mainly in marine sedimentary sequences, have also been identified in continental sequences, occurred episodically, and yet appear to be paced or triggered by orbital forcing. To constrain the timing and scale of the CIE relative to long-term baseline variability, we have constructed a 4.52 million year (myr) long, high-resolution (~ 3 kyr) bulk sediment carbon isotope record spanning the lower Eocene to upper Paleocene (C25r-C24n) from a pelagic sediment section recovered at ODP Site 1262 in the southeast Atlantic. This section, which was orbitally-tuned utilizing high-resolution core log physical property and geochemical records, is the most stratigraphically complete upper Paleocene to lower Eocene sequence recovered to date. Time-series analysis of the carbon isotope record along with a high-resolution Fe intensity record obtained by XRF core scanner reveal cyclicity with variance concentrated primarily in the precession (21 kyr) and eccentricity bands (100 and 400-kyr) throughout the upper Paleocene-lower Eocene. In general, minima in δ 13C correspond with peaks in Fe (i.e., carbonate dissolution), both of which appear to be in phase with maxima in eccentricity. This covariance is consistent with excess oceanic uptake of isotopically depleted carbon resulting in lower carbonate saturation during periods of high eccentricity. This relationship includes all late Paleocene and early Eocene CIE confirming pacing by orbital forcing. The lone exception is the PETM, which appears to be out of phase with the 400-kyr cycle, though possibly in phase with the 100-kyr cycle, reinforcing the notion that a mechanism other than orbital forcing and/or an additional source of carbon is required to account for the

  6. Assessing Carbon-Based Anodes for Lithium-Ion Batteries: A Universal Description of Charge-Transfer Binding

    DOE PAGES

    Liu, Yuanyue; Wang, Y. Morris; Yakobson, Boris I.; ...

    2014-07-11

    Many key performance characteristics of carbon-based lithium-ion battery anodes are largely determined by the strength of binding between lithium (Li) and sp 2 carbon (C), which can vary significantly with subtle changes in substrate structure, chemistry, and morphology. We use density functional theory calculations to investigate the interactions of Li with a wide variety of sp 2 C substrates, including pristine, defective, and strained graphene, planar C clusters, nanotubes, C edges, and multilayer stacks. In almost all cases, we find a universal linear relation between the Li-C binding energy and the work required to fill previously unoccupied electronic states withinmore » the substrate. This suggests that Li capacity is predominantly determined by two key factors—namely, intrinsic quantum capacitance limitations and the absolute placement of the Fermi level. This simple descriptor allows for straightforward prediction of the Li-C binding energy and related battery characteristics in candidate C materials based solely on the substrate electronic structure. It further suggests specific guidelines for designing more effective C-based anodes. Furthermore, this method should be broadly applicable to charge-transfer adsorption on planar substrates, and provides a phenomenological connection to established principles in supercapacitor and catalyst design.« less

  7. Early Precambrian Carbonate and Evapolite Sediments: Constraints on Environmental and Biological Evolution

    NASA Technical Reports Server (NTRS)

    Grotzinger, John P.

    2002-01-01

    The work accomplished under NASA Grant NAG5-6722 was very successful. Our lab was able to document the occurrence and distribution of evaporite-to-carbonate transitions in several basins during Precambrian time, to help constrain the long-term chemical evolution of seawater.

  8. Litho- and biofacies of Early Cretaceous rudist-bearing carbonate sediments in northeastern Japan

    NASA Astrophysics Data System (ADS)

    Sano, Shin-ichi

    1995-11-01

    Carbonate blocks of late Aptian (Lower Cretaceous) age occur in the Lower Yezo Group of central Hokkaido in northeast Japan. The shallow-water carbonates were emplaced by gravity sliding and rock fall into a deep-water flysch basin. Various lithofacies can be distinguished within the blocks including massive wackestone, bedded packstone and micro-oncoid grainstone, containing corals, rudists, an oyster, gastropods, calcareous algae and an orbitolinid foraminifer. Facies and palaeoecological analyses suggest deposition of low-energy biostromes and sand banks in open lagoonal and restricted environments with local higher-energy shoals and beaches. The presence of calcareous sandstones and abundant insoluble residues in limestones suggest deposition in an attached carbonate platform close to a supply of terrigenous material, rather than deposition upon seamounts within an oceanic setting. A narrow rimmed shelf in tropical-subtropical conditions would have been the depositional environment for these carbonates, which were subsequently deformed into blocks and transported into deep water as a result of the tectonic collapse of the platform.

  9. Impacts of intensive forestry on early rotation trends in site carbon pools in the southeastern US

    Treesearch

    Raija Laiho; Felipe Sanchez; Allan Tiarks; Phillip M. Dougherty; Carl C. Trettin

    2003-01-01

    The effects of different silvicultural practices on site, especially soil, carbon (C) pools are still poorly known. We studied changes in site C pools during the first 5 years following harvesting and conversion of two extensively managed pine-hardwood stands to intensively managed loblolly pine plantations. One study site was located on the lower Atlantic Coastal...

  10. Planetary biology and microbial ecology. Biochemistry of carbon and early life

    NASA Technical Reports Server (NTRS)

    Margulis, L. (Editor); Nealson, K. H. (Editor); Taylor, I. (Editor)

    1983-01-01

    Experiments made with cyanobacteria, phototrophic bacteria, and methanogenic bacteria are detailed. Significant carbon isotope fractionation data is included. Taken from well documented extant microbial communities, this data provides a basis of comparison for isotope fractionation values measured in Archean and Proterozoic (preCambrian) rocks. Media, methods, and techniques used to acquire data are also described.

  11. Early stages of carbonate mineralization revealed from molecular simulations: Implications for biomineral formation

    NASA Astrophysics Data System (ADS)

    Wallace, A. F.; DeYoreo, J.; Banfield, J. F.

    2011-12-01

    The carbonate mineral constituents of many biomineralized products, formed both in and ex vivo, grow by a multi-stage crystallization process that involves the nucleation and structural reorganization of transient amorphous phases. The existence of transient phases and cluster species has significant implications for carbonate nucleation and growth in natural and engineered environments, both modern and ancient. The structure of these intermediate phases remains elusive, as does the nature of the disorder to order transition, however, these process details may strongly influence the interpretation of elemental and isotopic climate proxy data obtained from authigenic and biogenic carbonates. While molecular simulations have been applied to certain aspects of crystal growth, studies of metal carbonate nucleation are strongly inhibited by the presence of kinetic traps that prevent adequate sampling of the potential landscape upon which the growing clusters reside within timescales accessible by simulation. This research addresses this challenge by marrying the recent Kawska-Zahn (KZ) approach to simulation of crystal nucleation and growth from solution with replica-exchange molecular dynamics (REMD) techniques. REMD has been used previously to enhance sampling of protein conformations that occupy energy wells that are separated by sizable thermodynamic and kinetic barriers, and is used here to probe the initial formation and onset of order within hydrated calcium and iron carbonate cluster species during nucleation. Results to date suggest that growing clusters initiate as short linear ion chains that evolve into two- and three-dimensional structures with continued growth. The planar structures exhibit an obvious 2d lattice, while establishment of a 3d lattice is hindered by incomplete ion desolvation. The formation of a dehydrated core consisting of a single carbonate ion is observed when the clusters are ~0.75 nm. At the same size a distorted, but discernible

  12. Depositional environments and cyclicity of the Early Ordovician carbonate ramp in the western Tarim Basin (NW China)

    NASA Astrophysics Data System (ADS)

    Guo, Chuan; Chen, Daizhao; Song, Yafang; Zhou, Xiqiang; Ding, Yi; Zhang, Gongjing

    2018-06-01

    During the Early Ordovician, the Tarim Basin (NW China) was mainly occupied by an extensive shallow-water carbonate platform, on which a carbonate ramp system was developed in the Bachu-Keping area of the western part of the basin. Three well-exposed typical outcrop sections of the Lower Ordovician Penglaiba Formation were investigated in order to identify the depositional facies and to clarify origins of meter-scale cycles and depositional sequences, thereby the platform evolution. Thirteen lithofacies are identified and further grouped into three depositional facies (associations): peritidal, restricted and open-marine subtidal facies. These lithofacies are vertically stacked into meter-scale, shallowing-upward peritidal and subtidal cycles. The peritidal cycles are mainly distributed in the lower and uppermost parts of the Penglaiba Formation deposited in the inner-middle ramp, and commonly start with shallow subtidal to intertidal facies followed by inter- to supratidal facies. In contrast, the subtidal cycles occur throughout the formation mostly in the middle-outer ramp and are dominated by shallow to relatively deep (i.e., intermediate) subtidal facies. The dominance of asymmetrical and incomplete cycles suggests a dominant control of Earth's orbital forcing on the cyclic deposition on the platform. On the basis of vertical facies and cycle stacking patterns, and accommodation changes illustrated by the Fischer plots from all studied sections, five third-order depositional sequences are recognized in the Penglaiba Formation. Individual sequences comprise a lower transgressive part and an upper regressive one. In shallow-water depositional environments, the transgressive packages are dominated by thicker-than-average subtidal cycles, indicating an increase in accommodation space, whereas regressive parts are mainly represented by thinner-than-average peritidal and subtidal cycles, denoting a decrease in accommodation space. In contrast, in intermediate to

  13. Response of carbon isotopic compositions of Early-Middle Permian coals in North China to palaeo-climate change

    NASA Astrophysics Data System (ADS)

    Ding, Dianshi; Liu, Guijian; Sun, Xiaohui; Sun, Ruoyu

    2018-01-01

    To investigate the magnitude to which the carbon isotopic ratio (δ13C) varies in coals in response to their contemporary terrestrial environment, the Early-Middle Permian Huainan coals (including coals from the Shanxi Formation, Lower Shihezi Formation and Upper Shihezi Formation) in North China were systematically sampled. A 2.5‰ variation range of δ13C values (-25.15‰ to -22.65‰) was observed in Huainan coals, with an average value of -24.06‰. As coal diagenesis exerts little influence on carbon isotope fractionation, δ13C values in coals were mainly imparted by those of coal-forming flora assemblages which were linked to the contemporary climate. The δ13C values in coals from the Shanxi and Lower Shihezi Formations are variable, reflecting unstable climatic oscillations. Heavy carbon isotope is enriched in coals of the Capitanian Upper Shihezi Formation, implying a shift to high positive δ13C values of coeval atmospheric CO2. Notably, our study provides evidence of the Kamura event in the terrestrial environment for the first time.

  14. Quantifying early 17th century changes in Chesapeake Bay estuarine carbon dynamics from James River, VA oyster geochemistry

    NASA Astrophysics Data System (ADS)

    Grimm, B. L.; Spero, H. J.; Harding, J. M.

    2012-12-01

    The first successful European colonization of North America occurred in 1607 following the arrival of English settlers at Jamestown, Virginia. Within a few decades, land use changes and clear-cutting farming practices dramatically altered the terrestrial landscape and removed the overlying canopy and stabilizing root network of the previously-dominant hardwood forests. The Eastern oyster, Crassostrea virginica, has inhabited the Chesapeake Bay since the end of the last deglaciation. During the start of the Jamestown Colony, an extensive drought (1606-1612) shifted James River salinity zones upriver, expanding the available oyster habitat to the vicinity of Jamestown. This allowed the colonists to collect and eat oysters from areas near the colony down to the river's entry into the bay, and later discard the shells in wells and trash pits that have recently been excavated. The oysters' calcium carbonate shells discovered in these deposits act as multi-year stationary recorders preserving the local environmental chemistry throughout their life until collection. Here we present δ13C, δ18O, and radiocarbon data from historical oyster shell hinge transects that encompass the time period between ~1609 and the early 1700s. Samples include shells from the 1609 Jamestown freshwater well and five additional sites, as well as modern shells collected in 2006. Because shell δ13C and radiocarbon (14C) reflect James River δ13CDIC, it is possible to document carbon source changes during this period of land use change. Our preliminary data suggest a decrease in ambient δ13CDIC of approximately 2‰ between just prior to 1609 conditions and the modern estuary. This is most likely due to an increase in isotopically light organic carbon loading into the river as water moves more rapidly through the terrestrial system. Radiocarbon reservoir ages will also be presented to better constrain carbon flow through the system during this period of disturbance. δ18O measurements from the

  15. Literacy in Action: A Carbon-Neutral Field Program at Cornell University

    NASA Astrophysics Data System (ADS)

    Moore, A.; Derry, L.

    2010-12-01

    The Cornell Earth and Environmental Systems (EES) Field Program is a semester-length undergraduate field program located on the island of Hawai`i. The Hawaiian Islands are the world’s most dynamic natural laboratory and the premier location for Earth systems research and education. While there are compelling reasons for students and faculty to travel from the US mainland to Hawai`i, the air and ground travel that comprises the program carries a large carbon footprint. This liability is also an extraordinary educational opportunity. For the past two years EES students have been challenged to make the program carbon-neutral. They are asked to devise a set of criteria for a credible and defensible zero-CO2 footprint and then to put their plan into action. The C-neutral project consists of three elements: (1) quantifying CO2 emissions, (2) reducing emissions wherever possible, and (3) offsetting emissions that cannot be eliminated. In quantifying emissions six areas are identified: air travel, ground travel, domestic electricity, natural gas, food, and waste. Emissions reductions include all of the standard “carpool--turn it down--turn it off “ conservation behaviors, with special emphasis on food and waste; eating local and organic, shopping at re-use centers, and compost and recycling of garbage. Our program facility utilizes solar hot water and is equipped with neither heat nor air conditioning, thus domestic energy use is low. Students tabulate all of our energy use and calculate the resulting CO2 emissions for all program participants for a period of four months. The CO2 offsetting strategy is conducted in collaboration with a native ecosystem restoration project. Students participate in all aspects of forest restoration, including seed collection, germination and outplanting of native plant species and removal of invasive pest species. The initial goal of this locally-supported project was to restore degraded pasture to native forest. The EES students have

  16. Major early Eocene carbon cycle perturbations and changes in planktic foraminiferal assemblages from the southeast Atlantic Ocean (ODP Site 1263)

    NASA Astrophysics Data System (ADS)

    Luciani, Valeria; D'Onofrio, Roberta; Dickens, Gerald Roy; Wade, Bridget

    2017-04-01

    On a paleoclimatic perspective the early Paleogene represents one of the most interesting and dynamic intervals of the Earth's history. Present record indicates that the Earth climate system reached its Cenozoic maximum peak of global warming and probably of pCO2 during the early Eocene climatic optimum (EECO, 49-53 Ma). Superimposed to the general trend, our planet experienced short-term ( 40-200 kyr) repeated peaks in global temperatures and major changes in the carbon cycle, known as hyperthermals. Great scientific interest has been focused on the early Paleogene hyperthermal events, given the assumed similarity with the current climatic scenario. Less attention has been dedicated to the EECO long lasting perturbation of extraordinary warming thus many characters of this interval still remain largely unconstrained, especially as for the biotic response. We present here results on early Eocene planktic foraminiferal analysis from the southeast Atlantic Ocean Drilling Program (ODP) Site 1263 (Walvis Ridge, Leg 208) to explore possible relationship between changes in assemblages and carbon cycle perturbation. The time interval is of particular interest for an abrupt switch occurred at low-latitude of the northern hemisphere between two important calcifiers of the tropical-subtropical early Paleogene oceans, the genera Morozovella and Acarinina at the carbon isotopic excursion known as J event, at the EECO onset. Precisely, the relative abundance of Morozovella permanently decreased by at least half, along with a progressive decrease in the number of species. Concomitantly, Acarinina almost doubled its abundance and diversified. Site 1263 was located during the early Eocene at a latitude of 40° south therefore representing a temperate setting of southern hemisphere not yet explored for planktic foraminiferal changes. We document a permanent decrease in Morozovella abundance at the beginning of the EECO, although this decline is delayed by 165 kyr with respect to

  17. Planktic foraminiferal response to early Eocene carbon cycle perturbations in the southeast Atlantic Ocean (ODP Site 1263)

    NASA Astrophysics Data System (ADS)

    Luciani, Valeria; D'Onofrio, Roberta; Dickens, Gerald R.; Wade, Bridget S.

    2017-11-01

    At low latitude locations in the northern hemisphere, striking changes in the relative abundances and diversity of the two dominant planktic foraminifera genera, Morozovella and Acarinina, are known to have occurred close to the Early Eocene Climatic Optimum (EECO; 49-53 Ma). Lower Eocene carbonate-rich sediments at Ocean Drilling Program (ODP) Site 1263 were deposited on a bathymetric high (Walvis Ridge) at 40° S, and afford an opportunity to examine such planktic foraminiferal assemblage changes in a temperate southern hemisphere setting. We present here quantified counts of early Eocene planktic foraminiferal assemblages from Hole 1263B, along with bulk sediment stable isotope analyses and proxy measurements for carbonate dissolution. The bulk sediment δ13C record at Site 1263 resembles similar records generated elsewhere, such that known and inferred hyperthermal events can be readily identified. Although some carbonate dissolution has occurred, the well-preserved planktic foraminiferal assemblages mostly represent primary changes in environmental conditions. Our results document the permanent decrease in Morozovella abundance and increase in Acarinina abundance at the beginning of the EECO, although this switch occurred 165 kyr after that at low-latitude northern hemisphere locations. This suggests that unfavourable environmental conditions for morozovellids at the start of the EECO, such as sustained passage of a temperature threshold or other changes in surface waters, occurred at lower latitudes first. The remarkable turnover from Morozovella to Acarinina was widely geographically widespread, although the causal mechanism remains elusive. In addition, at Site 1263, we document the virtual disappearance within the EECO of the biserial chiloguembelinids, commonly considered as inhabiting intermediate water depths, and a reduction in abundance of the thermocline-dwelling subbotinids. We interpret these changes as signals of subsurface water properties

  18. Early Cretaceous Shallow-Water Platform Carbonates of the Bolkar Mountains, Central Taurides - South Turkey: Facies Analysis and Depositional Environments

    NASA Astrophysics Data System (ADS)

    Solak, Cemile; Taslı, Kemal; Koç, Hayati

    2016-10-01

    The study area comprises southern non-metamorphic part of the Bolkar Mountains which are situated in southern Turkey, eastern part of the Central Taurides. The studied five outcrops form geologically parts of the tectonostratigraphic units called as allochthonous Aladag Unit and autochthonous Geyikdagi Unit. The aim of this study is to describe microfacies and depositional environments of the Bolkar Mountains Early Cretaceous shallow- water platform carbonates. The Lower Cretaceous is represented by continuous thick- bedded to massive dolomite sequence ranging from 100 to 150 meters thick, which only contains locally laminated limestone intercalations in the Yüğlük section and thick to very thick-bedded uniform limestones ranging from approximately 50 to 120 meters, consist of mainly laminated- fenestral mudstone, peloidal-intraclastic grainstone-packstone, bioclastic packstone- wackestone, benthic foraminiferal-intraclastic grainstone-packstone, ostracod-fenestral wackestone-mudstone, dasycladacean algal packstone-wackestone and ooidal grainstone microfacies. Based on a combination sedimantological data, facies/microfacies and micropaleontological (predominantly dasycladacean algae and diverse benthic foraminifera) analysis, it is concluded that Early Cretaceous platform carbonates of the Bolkar Mountains reflect a tidally affected tidal-flat and restricted lagoon settings. During the Berriasian- Valanginian unfavourable facies for benthic foraminifera and dolomitization were predominate. In the Hauterivian-early Aptian, the effect of dolomitization largely disappeared and inner platform conditions still prevailed showing alternations of peritidal and lagoon facies, going from peritidal plains (representing various sub-environments including supratidal, intertidal area, tidal-intertidal ponds and ooid bars) dominated by ostracod and miliolids, to dasycladacean algae-rich restricted lagoons-subtidal. These environments show a transition in the vertical and

  19. The distribution of middle tropospheric carbon monoxide during early October 1984

    NASA Technical Reports Server (NTRS)

    Reichle, Henry G., Jr.; Connors, Vickie S.; Wallio, H. Andrew; Holland, J. Alvin; Sherrill, Robert T.; Casas, Joseph C.; Gormsen, Barbara B.

    1989-01-01

    The distribution of middle tropospheric carbon monoxide measure by the Measurement of Air Pollution from Satellites (MAPS) instrument carried aboard the space shuttle is reported. The data represent average mixing ratios in the middle troposphere and are presented in the form of maps that show the carbon monoxide mixing ratios averaged for 6 days of the mission. Comparisons with concurrent, direct measurements taken aboard aircraft show that the inferred concentrations are systematically low by from 20 to 40 percent depending upon which direct measurement calibration standard is used. The data show that there are very large CO sources resulting from biomass burning over South America and southern Africa. Measured mixing ratios were high over northeast Asia and were highly variable over Europe.

  20. Carbon cycling and net ecosystem production at an early stage of secondary succession in an abandoned coppice forest.

    PubMed

    Ohtsuka, Toshiyuki; Shizu, Yoko; Nishiwaki, Ai; Yashiro, Yuichiro; Koizumi, Hiroshi

    2010-07-01

    Secondary mixed forests are one of the dominant forest cover types in human-dominated temperate regions. However, our understanding of how secondary succession affects carbon cycling and carbon sequestration in these ecosystems is limited. We studied carbon cycling and net ecosystem production (NEP) over 4 years (2004-2008) in a cool-temperate deciduous forest at an early stage of secondary succession (18 years after clear-cutting). Net primary production of the 18-year-old forest in this study was 5.2 tC ha(-1 )year(-1), including below-ground coarse roots; this was partitioned into 2.5 tC ha(-1 )year(-1) biomass increment, 1.6 tC ha(-1 )year(-1) foliage litter, and 1.0 tC ha(-1 )year(-1) other woody detritus. The total amount of annual soil surface CO(2) efflux was 6.8 tC ha(-1 )year(-1), which included root respiration (1.9 tC ha(-1 )year(-1)) and heterotrophic respiration (RH) from soils (4.9 tC ha(-1 )year(-1)). The 18-year forest at this study site exhibited a great increase in biomass pool as a result of considerable total tree growth and low mortality of tree stems. In contrast, the soil organic matter (SOM) pool decreased markedly (-1.6 tC ha(-1 )year(-1)), although further study of below-ground detritus production and RH of SOM decomposition is needed. This young 18-year forest was a weak carbon sink (0.9 tC ha(-1 )year(-1)) at this stage of secondary succession. The NEP of this 18-year forest is likely to increase gradually because biomass increases with tree growth and with the improvement of the SOM pool through increasing litter and dead wood production with stand development.

  1. Stable carbon and sulfur isotopes as records of the early biosphere

    NASA Technical Reports Server (NTRS)

    Desmarais, David J.

    1989-01-01

    The abundance ratios of the stable isotopes of light elements such as carbon and sulfur can differ between various naturally-occurring chemical compounds. If coexisting compounds have achieved mutual chemical and isotopic equilibrium, then the relative isotopic composition can record the conditions at which equilibrium was last maintained. If coexisting chemical compounds indeed formed simultaneously but had not achieved mutual equilibrium, then their relative isotopic compositions often reflect the conditions and mechanisms associated with the kinetically controlled reactions responsible for their production. In the context of Mars, the stable isotopic compositions of various minerals might record not only the earlier environmental conditions of the planet, but also whether or not the chemistry of life ever occurred there. Two major geochemical reservoirs occur in Earth's crust, both for carbon and sulfur. In rocks formed in low temperature sedimentary environments, the oxidized forms of these elements tend to be enriched in the isotope having the larger mass, relative to the reduced forms. In sediments where the organics and sulfides were formed by biological processes, these isotopic contrasts were caused by the processes of biological CO2 fixation and dissimilatory sulfate reduction. Such isotopic contrasts between oxidized and reduced forms of carbon and sulfur are permitted by thermodynamics at ambient temperatures. However, nonbiological chemical reactions associated with the production of organic matter and the reduction of organics and sulfides are extremely slow at ambient temperatures. Thus the synthesis of organics and sulfides under ambient conditions illustrates life's profound role as a chemical catalyst that has altered the chemistry of Earth's crust. Because the stable isotopes of carbon and sulfur can reflect their chemistry, they are useful probes of the Martian surface.

  2. Carbon Dioxide Clouds at High Altitude in the Tropics and in an Early Dense Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Colaprete, Anthony; Toon, Owen B.

    2001-01-01

    We use a time dependent, microphysical cloud model to study the formation of carbon dioxide clouds in the Martian atmosphere. Laboratory studies by Glandor et al. show that high critical supersaturations are required for cloud particle nucleation and that surface kinetic growth is not limited. These conditions, which are similar to those for cirrus clouds on Earth, lead to the formation of carbon dioxide ice particles with radii greater than 500 micrometers and concentrations of less than 0.1 cm(exp -3) for typical atmospheric conditions. Within the current Martian atmosphere, CO2 cloud formation is possible at the poles during winter and at high altitudes in the tropics during periods of increased atmospheric dust loading. In both cases, temperature perturbations of several degrees below the CO2 saturation temperature are required to nucleate new cloud particles suggesting that dynamical processes are the most common initiators of carbon dioxide clouds rather than diabatic cooling. The microphysical cloud model, coupled to a two-stream radiative transfer model, is used to reexamine the impact of CO2 clouds on the surface temperature within a dense CO2 atmosphere. The formation of carbon dioxide clouds leads to a warmer surface than what would be expected for clear sky conditions. The amount of warming is sensitive to the presence of dust and water vapor in the atmosphere, both of which act to dampen cloud effects. The radiative warming associated with cloud formation, as well as latent heating, work to dissipate the clouds when present. Thus, clouds never last for periods much longer than several days, limiting their overall effectiveness for warming the surface. The time average cloud optical depth is approximately unity leading to a 5-10 K warming, depending on the surface pressure. However, the surface temperature does not rise about the freezing point of liquid water even for pressures as high as 5 bars, at a solar luminosity of 75% the current value.

  3. Early Combination of Material Characteristics and Toxicology Is Useful in the Design of Low Toxicity Carbon Nanofiber

    PubMed Central

    Jensen, Ellen K.; Larsen, Sten Y.; Nygaard, Unni C.; Marioara, Calin D.; Syversen, Tore

    2012-01-01

    This paper describes an approach for the early combination of material characterization and toxicology testing in order to design carbon nanofiber (CNF) with low toxicity. The aim was to investigate how the adjustment of production parameters and purification procedures can result in a CNF product with low toxicity. Different CNF batches from a pilot plant were characterized with respect to physical properties (chemical composition, specific surface area, morphology, surface chemistry) as well as toxicity by in vitro and in vivo tests. A description of a test battery for both material characterization and toxicity is given. The results illustrate how the adjustment of production parameters and purification, thermal treatment in particular, influence the material characterization as well as the outcome of the toxic tests. The combination of the tests early during product development is a useful and efficient approach when aiming at designing CNF with low toxicity. Early quality and safety characterization, preferably in an iterative process, is expected to be efficient and promising for this purpose. The toxicity tests applied are preliminary tests of low cost and rapid execution. For further studies, effects such as lung inflammation, fibrosis and respiratory cancer are recommended for the more in-depth studies of the mature CNF product.

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

    PubMed

    Dawson, Angela; Bateson, Deborah; Estoesta, Jane; Sullivan, Elizabeth

    2016-10-22

    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. 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. 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. Key insights for service delivery in Australia include the: establishment of standards, provision of choice of procedure, improved provider education and training and the expansion of telemedicine for medical

  5. The Early Universe

    NASA Astrophysics Data System (ADS)

    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.

  6. Massive impact-induced release of carbon and sulfur gases in the early Earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Marchi, S.; Black, B. A.; Elkins-Tanton, L. T.; Bottke, W. F.

    2016-09-01

    Recent revisions to our understanding of the collisional history of the Hadean and early-Archean Earth indicate that large collisions may have been an important geophysical process. In this work we show that the early bombardment flux of large impactors (>100 km) facilitated the atmospheric release of greenhouse gases (particularly CO2) from Earth's mantle. Depending on the timescale for the drawdown of atmospheric CO2, the Earth's surface could have been subject to prolonged clement surface conditions or multiple freeze-thaw cycles. The bombardment also delivered and redistributed to the surface large quantities of sulfur, one of the most important elements for life. The stochastic occurrence of large collisions could provide insights on why the Earth and Venus, considered Earth's twin planet, exhibit radically different atmospheres.

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

    NASA Technical Reports Server (NTRS)

    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.

  8. r-Process Nucleosynthesis in the Early Universe Through Fast Mergers of Compact Binaries in Triple Systems

    NASA Astrophysics Data System (ADS)

    Bonetti, Matteo; Perego, Albino; Capelo, Pedro R.; Dotti, Massimo; Miller, M. Coleman

    2018-05-01

    Surface abundance observations of halo stars hint at the occurrence of r-process nucleosynthesis at low metallicity ([Fe/H] < -3), possibly within the first 108 yr after the formation of the first stars. Possible loci of early-Universe r-process nucleosynthesis are the ejecta of either black hole-neutron star or neutron star-neutron star binary mergers. Here, we study the effect of the inclination-eccentricity oscillations raised by a tertiary (e.g. a star) on the coalescence time-scale of the inner compact object binaries. Our results are highly sensitive to the assumed initial distribution of the inner binary semi-major axes. Distributions with mostly wide compact object binaries are most affected by the third object, resulting in a strong increase (by more than a factor of 2) in the fraction of fast coalescences. If instead the distribution preferentially populates very close compact binaries, general relativistic precession prevents the third body from increasing the inner binary eccentricity to very high values. In this last case, the fraction of coalescing binaries is increased much less by tertiaries, but the fraction of binaries that would coalesce within 108 yr even without a third object is already high. Our results provide additional support to the compact-binary merger scenario for r-process nucleosynthesis.

  9. First identification of direct collapse black hole candidates in the early Universe in CANDELS/GOODS-S

    NASA Astrophysics Data System (ADS)

    Pacucci, Fabio; Ferrara, Andrea; Grazian, Andrea; Fiore, Fabrizio; Giallongo, Emanuele; Puccetti, Simonetta

    2016-06-01

    The first black hole seeds, formed when the Universe was younger than ˜500 Myr, are recognized to play an important role for the growth of early (z ˜ 7) supermassive black holes. While progresses have been made in understanding their formation and growth, their observational signatures remain largely unexplored. As a result, no detection of such sources has been confirmed so far. Supported by numerical simulations, we present a novel photometric method to identify black hole seed candidates in deep multiwavelength surveys. We predict that these highly obscured sources are characterized by a steep spectrum in the infrared (1.6-4.5 μm), I.e. by very red colours. The method selects the only two objects with a robust X-ray detection found in the CANDELS/GOODS-S survey with a photometric redshift z ≳ 6. Fitting their infrared spectra only with a stellar component would require unrealistic star formation rates (≳2000 M⊙ yr-1). To date, the selected objects represent the most promising black hole seed candidates, possibly formed via the direct collapse black hole scenario, with predicted mass >105 M⊙. While this result is based on the best photometric observations of high-z sources available to date, additional progress is expected from spectroscopic and deeper X-ray data. Upcoming observatories, like the JWST, will greatly expand the scope of this work.

  10. Early diagenesis driven by widespread meteoric infiltration of a Central European carbonate ramp: A reinterpretation of the Upper Muschelkalk

    NASA Astrophysics Data System (ADS)

    Adams, Arthur; Diamond, Larryn W.

    2017-12-01

    Meteoric diagenesis of carbonate ramps is often difficult to interpret and can commonly be confused with other coinciding diagenetic processes. The Middle Triassic Upper Muschelkalk of Switzerland provides an insightful case in which the effects of several overprinting diagenetic environments, including matrix dolomitization, can be clearly unravelled. Previous studies suggested that diagenesis took place in connate marine waters, with later meteoric waters being invoked to explain recrystallization of dolomite. In this study, diagenetic analyses (C-O stable isotope ratios, thin-section point counting, cathodoluminescence and UV-fluorescence microscopy) of calcitic bioclastic samples have revealed that early diagenesis (pre-stylolitization) and the accompanying porosity evolution did not occur exclusively in the presence of marine fluids. Five sequential stages of diagenesis have been identified: marine, shallow burial, mixing-zone, meteoric and dolomitization. Marine diagenesis induced precipitation of bladed and inclusion-rich syntaxial cements that fluoresce strongly under UV-light. Both cements account for a mean 7.5 vol% reduction in the porosity of bioclastic beds. Shallow burial diagenesis likely induced mouldic porosity and associated fluorescent dog-tooth cementation. Based on light oxygen isotope and elevated strontium isotope ratios, matrix aragonite-calcite neomorphism is interpreted to have occurred in a mixture of marine and meteoric fluids. The combination of shallow burial and mixing-zone processes reduced porosity on average by 4.8 vol%. Evidence for subsequent meteoric diagenesis is found in abundant dog-tooth and blocky calcite cements that have mean δ18OVPDB of - 9.36‰ and no signs of recrystallization. These meteoric cements reduced porosity by a further 13.4 vol%. Percolation of meteoric water through the ramp was driven by hydraulic gradients on an adjacent basement high, which was exposed by a cycle of early Ladinian regressions

  11. New Insights into Early Cenozoic Carbon Cycling: Continental Ecosystem Response to Orbital Forcing in the Lacustrine Green River Formation (Western US) at the Conclusion of the Early Eocene Climatic Optimum

    NASA Astrophysics Data System (ADS)

    Musher, D.; Grogan, D. S.; Whiteside, J. H.

    2010-12-01

    A series of extreme warming events, known as hyperthermals, interrupted the equable climate conditions predominant during the early Cenozoic hothouse. In marine sediments, these hyperthermals are marked by prominent negative carbon isotope excursions, indicative of dramatic and abrupt changes in the global exogenic carbon pool, as well as carbonate dissolution horizons and benthic foraminiferal extinctions. Hyperthermals are well documented in the marine record, but it is less clear how patterns of global carbon cycling manifested in early Cenozoic terrestrial environments, although some studies have documented amplified excursions relative to that of the marine record. The lacustrine Eocene Green River Formation of Utah is an excellent system for studying the continental environmental context of global carbon cycle dynamics during this time. These sediments span a ~15 Myr time interval, including the entire Early Eocene Climatic Optimum (EECO) and the transition to the long-term Cenozoic cooling trend. To investigate the relationship between the continental carbon record and global carbon cycling, climate, and orbital forcing, we studied a detailed section from the P-4 core drilled in the Uinta Basin bracketing the famous “Mahogany Bed”, a petroliferous layer of oil shale recording a period of enhanced productivity and carbon burial near the end of the EECO. Our carbon isotope measurements of high molecular weight n-alkanes across this boundary suggest a stable global carbon cycle and climate regime persisting ~400 kyr at the terminal EECO. Frequency spectra of published oil yield and gamma ray data from this section reveal concentrated power at Milankovitch frequencies, permitting the assembly of a robust age model. In concert with radioisotopic age control, our orbital chronology allows for comparison of our carbon cycle record to early Eocene astronomical solutions. We show that the Mahogany Bed corresponds to strong minima in short and long eccentricity

  12. Changing Trends within the Population of Children Who Are Deaf or Hard of Hearing in Flanders (Belgium): Effects of 12 Years of Universal Newborn Hearing Screening, Early Intervention, and Early Cochlear Implantation

    ERIC Educational Resources Information Center

    De Raeve, Leo; Lichtert, Guido

    2012-01-01

    The purpose of this study is to show the changing trends within the population of children who are deaf and hard of hearing in Belgium over the last 12 years. The combination of Universal Newborn Hearing Screening programs, early intervention, and cochlear implants have tremendously influenced the education and support of children who are deaf or…

  13. The conservative behavior of dissolved organic carbon in surface waters of the southern Chukchi Sea, Arctic Ocean, during early summer

    PubMed Central

    Tanaka, Kazuki; Takesue, Nobuyuki; Nishioka, Jun; Kondo, Yoshiko; Ooki, Atsushi; Kuma, Kenshi; Hirawake, Toru; Yamashita, Youhei

    2016-01-01

    The spatial distribution of dissolved organic carbon (DOC) concentrations and the optical properties of dissolved organic matter (DOM) determined by ultraviolet-visible absorbance and fluorescence spectroscopy were measured in surface waters of the southern Chukchi Sea, western Arctic Ocean, during the early summer of 2013. Neither the DOC concentration nor the optical parameters of the DOM correlated with salinity. Principal component analysis using the DOM optical parameters clearly separated the DOM sources. A significant linear relationship was evident between the DOC and the principal component score for specific water masses, indicating that a high DOC level was related to a terrigenous source, whereas a low DOC level was related to a marine source. Relationships between the DOC and the principal component scores of the surface waters of the southern Chukchi Sea implied that the major factor controlling the distribution of DOC concentrations was the mixing of plural water masses rather than local production and degradation. PMID:27658444

  14. Excitation of luminescence of the nanoporous bioactive nanocrystalline carbonate-substituted hydroxyapatite for early tooth disease detection

    NASA Astrophysics Data System (ADS)

    Goloshchapov, D. L.; Minakov, D. A.; Domashevskaya, E. P.; Seredin, P. V.

    This paper deals with the luminescence characteristics of an analogue of the mineral component of dental enamel of the nanocrystalline B-type carbonate-substituted hydroxyapatite (CHAP) with 3D defects (i.e. nanopores of ∼2-5 nm) on the nanocrystalline surface. The laser-induced luminescence (LIL) of the synthesized CHAP samples was in the range of ∼515 nm (∼2.4 eV) and is due to CO3 groups replacing the PO4 group. It was found that the intensity of the luminescence of the CHAP is caused by structurally incorporated CO3 groups in the HAP structure. Furthermore, the intensity of the luminescence also decreases as the number of the above intracentre defects (CO3) in the apatite structure declines. These results are potentially promising for developing the foundations for precise methods for the early detection of caries in human solid dental tissue.

  15. The Learning Experiences of Early-Career Indonesian Government Employees: A Case Study in Cross-Cultural Workforce Development Based in a University Environment

    ERIC Educational Resources Information Center

    Elsey, Barry; Omarova, Amina; Grill, Ronald

    2016-01-01

    The research provides a selective report on the learning experiences covering a whole year of study for a double-degree Master's programme by a cohort of early-career Indonesians. They were undertaking the second half of the programme at The University of Adelaide in South Australia, and for all 18 students it was their first taste of learning in…

  16. Continuity, Support, Togetherness and Trust: Findings from an Evaluation of a University-Administered Early Professional Development Programme for Teachers in England

    ERIC Educational Resources Information Center

    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…

  17. Aspects of Reading Acquisition; Proceedings of the Annual Hyman Blumberg Symposium on Research in Early Childhood Education (5th, Johns Hopkins University, Nov. 13-14, 1974).

    ERIC Educational Resources Information Center

    Guthrie, John T., Ed.

    Papers collected in this volume were presented at the Fifth Annual Blumberg Symposium on Research in Early Childhood Education, held at Johns Hopkins University in 1974. Selections include "Alexia" (D. Frank Benson), "Young Children's Expectations for Reading" (Doris R. Entwisle), "Relations between Acquisition of…

  18. An Analysis of the California State University and Colleges Early Retirement Incentive Program: A Report Pursuant to Chapter 656 of the Statutes of 1979.

    ERIC Educational Resources Information Center

    Reinhard, Raymond M.

    The California State University and Colleges' (CSUC) Early Retirement Incentive (ERI) Program is described, and information is presented of those who retire during a three-month period with an incentive bonus of two additional years of (unearned) retirement service credit. During the eligibility period 1,047 CSUC employees retired, and it appears…

  19. Test Review for Preschool-Wide Evaluation Tool (PreSET) Manual: Assessing Universal Program-Wide Positive Behavior Support in Early Childhood

    ERIC Educational Resources Information Center

    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,…

  20. Role Model Effects of Female STEM Teachers and Doctors on Early 20th Century University Enrollment in California. Research & Occasional Paper Series: CSHE.10.16

    ERIC Educational Resources Information Center

    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…

  1. Early and late seasonal carbon sequestration and allocation in larch trees growing on permafrost in Central Siberia

    NASA Astrophysics Data System (ADS)

    Masyagina, Oxana; Prokushkin, Anatoly; Kirdyanov, Alexander; Artyukhov, Aleksey; Udalova, Tatiana; Senchenkov, Sergey; Rublev, Aleksey

    2014-05-01

    Despite large geographic extent of deciduous conifer species Larix gmelinii, its seasonal photosynthetic activity and translocation of photoassimilated carbon within a tree remain poorly studied. To get better insight into productivity of larch trees growing on permafrost soils in Siberian larch biome we aimed to analyze dynamics of foliage parameters (i.e. leaf area, biomass, %N, %P etc.), seasonal dynamics of photosynthetic activity and apply whole tree labeling by 13CO2, which is powerful and effective tool for tracing newly developed assimilates translocation to tissues and organs of a tree (Kagawa et al., 2006; Keel et al., 2012). Experimental plot has been established in mature 105 year-old larch stand located within the continuous permafrost area near Tura settlement (Central Siberia, 64o17'13" N, 100o11'55" E, 148 m a.s.l.). Trees selected for experiments represented mean tree of the stand. Measurements of seasonal photosynthetic activity and foliar biomass sampling were arranged from early growing season (June 8, 2013) until yellowing and senescence of needles on September 17, 2013. Labeling by 13C in whole tree chamber was conducted by three pulses ([CO2]max ≤ 2,500 ppmv, 13CO2 (30% v/v)) at the early (June) and late (August) phase of growing season for different trees in 3 replicates each time. Both early season and late season labeling experiments demonstrated high rate of 13CO2 assimilation and respective enrichment of needle tissues by 13C: δ13C increased from -28.7 up to +670‰ just after labeling. However, there was distinct post-labeling dynamics of needle δ13C among two seasonal experiments. At the early season 13C depletion in labeled needles was slower, and δ13C approached after 40 days ca. +110 ‰ and remained constant till senescence. In the late season (August) needles were losing labeled C with much faster rate and approached only +1.5 ‰ upon senescence (28 days exposition). These findings suggest that in early season ca. 20% of

  2. How fresh is maple syrup? Sugar maple trees mobilize carbon stored several years previously during early springtime sap-ascent.

    PubMed

    Muhr, Jan; Messier, Christian; Delagrange, Sylvain; Trumbore, Susan; Xu, Xiaomei; Hartmann, Henrik

    2016-03-01

    While trees store substantial amounts of nonstructural carbon (NSC) for later use, storage regulation and mobilization of stored NSC in long-lived organisms like trees are still not well understood. At two different sites with sugar maple (Acer saccharum), we investigated ascending sap (sugar concentration, δ(13) C, Δ(14) C) as the mobilized component of stored stem NSC during early springtime. Using the bomb-spike radiocarbon approach we were able to estimate the average time elapsed since the mobilized carbon (C) was originally fixed from the atmosphere and to infer the turnover time of stem storage. Sites differed in concentration dynamics and overall δ(13) C, indicating different growing conditions. The absence of temporal trends for δ(13) C and Δ(14) C indicated sugar mobilization from a well-mixed pool with average Δ(14) C consistent with a mean turnover time (TT) of three to five years for this pool, with only minor differences between the sites. Sugar maple trees hence appear well buffered against single or even several years of negative plant C balance from environmental stress such as drought or repeated defoliation by insects. Manipulative investigations (e.g. starvation via girdling) combined with Δ(14) C measurements of this mobilized storage pool will provide further new insights into tree storage regulation and functioning. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  3. Biogeochemical Cycles of Carbon and Sulfur on Early Earth (and on Mars?)

    NASA Technical Reports Server (NTRS)

    DesMarais, D. J.

    2004-01-01

    The physical and chemical interactions between the atmosphere, hydrosphere, geosphere and biosphere can be examined for elements such as carbon (C) and sulfur (S) that have played central roles for both life and the environment. The compounds of C are highly important, not only as organic matter, but also as atmospheric greenhouse gases, pH buffers in seawater, oxidation-reduction buffers virtually everywhere, and key magmatic constituents affecting plutonism and volcanism. S assumes important roles as an oxidation-reduction partner with C and Fe in biological systems, as a key constituent in magmas and volcanic gases, and as a major influence upon pH in certain environments. These multiple roles of C and S interact across a network of elemental reservoirs interconnected by physical, chemical and biological processes. These networks are termed biogeochemical C and S cycles.

  4. Bolide impacts and the oxidation state of carbon in the Earth's early atmosphere

    NASA Technical Reports Server (NTRS)

    Kasting, J. F.

    1992-01-01

    A one-dimensional photochemical model was used to examine the effect of bolide impacts on the oxidation state of Earth's primitive atmosphere. The impact rate should have been high prior to 3.8 Ga before present, based on evidence derived from the Moon. Impacts of comets or carbonaceous asteroids should have enhanced the atmospheric CO/CO2 ratio by bringing in CO ice and/or organic carbon that can be oxidized to CO in the impact plume. Ordinary chondritic impactors would contain elemental iron that could have reacted with ambient CO2 to give CO. Nitric oxide (NO) should also have been produced by reaction between ambient CO2 and N2 in the hot impact plumes. High NO concentrations increase the atmospheric CO/CO2 ratio by increasing the rainout rate of oxidized gases. According to the model, atmospheric CO/CO2 ratios of unity or greater are possible during the first several hundred million years of Earth's history, provided that dissolved CO was not rapidly oxidized to bicarbonate in the ocean. Specifically, high atmospheric CO/CO2 ratios are possible if either: (1) the climate was cool (like today's climate), so that hydration of dissolved CO to formate was slow, or (2) the formate formed from CO was efficiently converted into volatile, reduced carbon compounds, such as methane. A high atmospheric CO/CO2 ratio may have helped to facilitate prebiotic synthesis by enhancing the production rates of hydrogen cyanide and formaldehyde. Formaldehyde may have been produced even more efficiently by photochemical reduction of bicarbonate and formate in Fe(++)-rich surface waters.

  5. Wear Characterization of Carbon Nanotubes Reinforced Acetal Spur, Helical, Bevel and Worm Gears Using a TS Universal Test Rig

    NASA Astrophysics Data System (ADS)

    Yousef, Samy; Osman, T. A.; Abdalla, Abdelrahman H.; Zohdy, Gamal A.

    2015-12-01

    Although the applications of nanotechnologies are increasing, there remains a significant barrier between nanotechnology and machine element applications. This work aims to remove this barrier by blending carbon nanotubes (CNT) with common types of acetal polymer gears (spur, helical, bevel and worm). This was done by using adhesive oil (paraffin) during injection molding to synthesize a flange and short bars containing 0.02% CNT by weight. The flanges and short bars were machined using hobbing and milling machines to produce nanocomposite polymer gears. Some defects that surfaced in previous work, such as the appearance of bubbles and unmelted pellets during the injection process, were avoided to produce an excellent dispersion of CNT in the acetal. The wear resistances of the gears were measured by using a TS universal test rig using constant parameters for all of the gears that were fabricated. The tests were run at a speed of 1420 rpm and a torque of 4 Nm. The results showed that the wear resistances of the CNT/acetal gears were increased due to the addition of CNT, especially the helical, bevel and worm gears.

  6. Universal model of bias-stress-induced instability in inkjet-printed carbon nanotube networks field-effect transistors

    NASA Astrophysics Data System (ADS)

    Jung, Haesun; Choi, Sungju; Jang, Jun Tae; Yoon, Jinsu; Lee, Juhee; Lee, Yongwoo; Rhee, Jihyun; Ahn, Geumho; Yu, Hye Ri; Kim, Dong Myong; Choi, Sung-Jin; Kim, Dae Hwan

    2018-02-01

    We propose a universal model for bias-stress (BS)-induced instability in the inkjet-printed carbon nanotube (CNT) networks used in field-effect transistors (FETs). By combining two experimental methods, i.e., a comparison between air and vacuum BS tests and interface trap extraction, BS instability is explained regardless of either the BS polarity or ambient condition, using a single platform constituted by four key factors: OH- adsorption/desorption followed by a change in carrier concentration, electron concentration in CNT channel corroborated with H2O/O2 molecules in ambient, charge trapping/detrapping, and interface trap generation. Under negative BS (NBS), the negative threshold voltage shift (ΔVT) is dominated by OH- desorption, which is followed by hole trapping in the interface and/or gate insulator. Under positive BS (PBS), the positive ΔVT is dominated by OH- adsorption, which is followed by electron trapping in the interface and/or gate insulator. This instability is compensated by interface trap extraction; PBS instability is slightly more complicated than NBS instability. Furthermore, our model is verified using device simulation, which gives insights on how much each mechanism contributes to BS instability. Our result is potentially useful for the design of highly stable CNT-based flexible circuits in the Internet of Things wearable healthcare era.

  7. Early spring, severe frost events, and drought induce rapid carbon loss in high elevation meadows.

    PubMed

    Arnold, Chelsea; Ghezzehei, Teamrat A; Berhe, Asmeret Asefaw

    2014-01-01

    By the end of the 20th century, the onset of spring in the Sierra Nevada mountain range of California has been occurring on average three weeks earlier than historic records. Superimposed on this trend is an increase in the presence of highly anomalous "extreme" years, where spring arrives either significantly late or early. The timing of the onset of continuous snowpack coupled to the date at which the snowmelt season is initiated play an important role in the development and sustainability of mountain ecosystems. In this study, we assess the impact of extreme winter precipitation variation on aboveground net primary productivity and soil respiration over three years (2011 to 2013). We found that the duration of snow cover, particularly the timing of the onset of a continuous snowpack and presence of early spring frost events contributed to a dramatic change in ecosystem processes. We found an average 100% increase in soil respiration in 2012 and 2103, compared to 2011, and an average 39% decline in aboveground net primary productivity observed over the same time period. The overall growing season length increased by 57 days in 2012 and 61 days in 2013. These results demonstrate the dependency of these keystone ecosystems on a stable climate and indicate that even small changes in climate can potentially alter their resiliency.

  8. Self-healing of early age cracks in cement-based materials by mineralization of carbonic anhydrase microorganism

    PubMed Central

    Qian, Chunxiang; Chen, Huaicheng; Ren, Lifu; Luo, Mian

    2015-01-01

    This research investigated the self-healing potential of early age cracks in cement-based materials incorporating the bacteria which can produce carbonic anhydrase. Cement-based materials specimens were pre-cracked at the age of 7, 14, 28, 60 days to study the repair ability influenced by cracking time, the width of cracks were between 0.1 and 1.0 mm to study the healing rate influenced by width of cracks. The experimental results indicated that the bacteria showed excellent repairing ability to small cracks formed at early age of 7 days, cracks below 0.4 mm was almost completely closed. The repair effect reduced with the increasing of cracking age. Cracks width influenced self-healing effectiveness significantly. The transportation of CO2and Ca2+ controlled the self-healing process. The computer simulation analyses revealed the self-healing process and mechanism of microbiologically precipitation induced by bacteria and the depth of precipitated CaCO3 could be predicted base on valid Ca2+. PMID:26583014

  9. Carbon nanotubes as VEGF carriers to improve the early vascularization of porcine small intestinal submucosa in abdominal wall defect repair

    PubMed Central

    Liu, Zhengni; Feng, Xueyi; Wang, Huichun; Ma, Jun; Liu, Wei; Cui, Daxiang; Gu, Yan; Tang, Rui

    2014-01-01

    Insufficient early vascularization in biological meshes, resulting in limited host tissue incorporation, is thought to be the primary cause for the failure of abdominal wall defect repair after implantation. The sustained release of exogenous angiogenic factors from a biocompatible nanomaterial might be a way to overcome this limitation. In the study reported here, multiwalled carbon nanotubes (MWNT) were functionalized by plasma polymerization to deliver vascular endothelial growth factor165 (VEGF165). The novel VEGF165-controlled released system was incorporated into porcine small intestinal submucosa (PSIS) to construct a composite scaffold. Scaffolds incorporating varying amounts of VEGF165-loaded functionalized MWNT were characterized in vitro. At 5 weight percent MWNT, the scaffolds exhibited optimal properties and were implanted in rats to repair abdominal wall defects. PSIS scaffolds incorporating VEGF165-loaded MWNT (VEGF–MWNT–PSIS) contributed to early vascularization from 2–12 weeks postimplantation and obtained more effective collagen deposition and exhibited improved tensile strength at 24 weeks postimplantation compared to PSIS or PSIS scaffolds, incorporating MWNT without VEGF165 loading (MWNT–PSIS). PMID:24648727

  10. Mission Study for Generation-X: A Large Area and High Angular Observatory to Study the Early Universe

    NASA Technical Reports Server (NTRS)

    Brissenden, Roger

    2005-01-01

    In this report we provide a summary of the technical progress achieved during the last year Generation-X Vision Mission Study. In addition, we provide a brief programmatic status. The Generation-X (Gen-X) Vision Mission Study investigates the science requirements, mission concepts and technology drivers for an X-ray telescope designed to study the new frontier of astrophysics: the birth and evolution of the first stars, galaxies and black holes in the early Universe. X-ray astronomy offers an opportunity to detect these via the activity of the black holes, and the supernova explosions and gamma-ray burst afterglows of the massive stars. However, such objects are beyond the grasp of current missions which are operating or even under development. Our team has conceived a Gen-X Vision Mission based on an X-ray observatory with 100 m2 collecting area at 1 keV (1000 times larger than Chandra) and 0.1 arcsecond angular resolution (several times better than Chandra and 50 times better than the Constellation-X resolution goal). Such a high energy observatory will be capable of detecting the earliest black holes and galaxies in the Universe, and will also study extremes of density, gravity, magnetic fields, and kinetic energy which cannot be created in laboratories. In our study we develop the mission concept and define candidate technologies and performance requirements for Gen-X. The baseline Gen-X mission involves four 8 m diameter X-ray telescopes operating at Sun-Earth L2. We trade against an alternate concept of a single 26 m diameter telescope with focal plane instruments on a separate spacecraft. A telescope of this size will require either robotic or human-assisted in-flight assembly. The required effective area implies that extremely lightweight grazing incidence X-ray optics must be developed. To achieve the required areal density of at least 100 times lower than for Chandra, we study 0.2 mm thick mirrors which have active on-orbit figure control. We also study

  11. Synchronization of the astronomical time scales in the Early Toarcian: A link between anoxia, carbon-cycle perturbation, mass extinction and volcanism

    NASA Astrophysics Data System (ADS)

    Ait-Itto, Fatima-Zahra; Martinez, Mathieu; Price, Gregory D.; Ait Addi, Abdellah

    2018-07-01

    The Late Pliensbachian-Early Toarcian is a pivotal time in the Mesozoic era, marked by pronounced carbon-isotope excursions, biotic crises and major climatic and oceanographic changes. Here we present new high-resolution carbon-isotope and magnetic-susceptibility measurements from an expanded hemipelagic Late Pliensbachian-Early Toarcian section from the Middle Atlas Basin (Morocco). Our new astronomical calibration allows the construction of an orbital time scale based on the 100-kyr eccentricity cycle. The Early Toarcian Polymorphum Zone contains 10 to 10.5 repetitions of the 100-kyr eccentricity both in the carbon-isotope and the magnetic-susceptibility data, leading to an average duration of 1.00 ± 0.08 myr. We also show that the Late Pliensbachian-Early Toarcian global carbon-cycle perturbation has an average duration of 0.24 ± 0.02 myr. These durations are comparable to previous astrochronological time scales provided for this time interval in the most complete sections of the Tethyan area, and longer than what has been provided in condensed sections. Anchoring this framework on published radiometric ages and astrochronological time scales, we estimate that the carbon-cycle perturbation of the Late Pliensbachian-Early Toarcian corresponds with the early phase of the Karoo and Chonke Aike large igneous provinces. Likewise, our new age constraints confirm that the Toarcian oceanic anoxic event is synchronous to the main phase of the Ferrar volcanic activity. Thus, these successive and short phases of the volcanic activity may have been at the origin of the successive phases of the mass extinctions observed in marine biotas in the Pliensbachian and Toarcian times.

  12. Universal liquid-phase laser fabrication of various nano-metals encapsulated by ultrathin carbon shells for deep-UV plasmonics.

    PubMed

    Yu, Miao; Yang, Chao; Li, Xiao-Ming; Lei, Tian-Yu; Sun, Hao-Xuan; Dai, Li-Ping; Gu, Yu; Ning, Xue; Zhou, Ting; Wang, Chao; Zeng, Hai-Bo; Xiong, Jie

    2017-06-29

    The exploration of localized surface plasmon resonance (LSPR) beyond the usual visible waveband, for example within the ultraviolet (UV) or deep-ultraviolet (D-UV) regions, is of great significance due to its unique applications in secret communications and optics. However, it is still challenging to universally synthesize the corresponding metal nanostructures due to their high activity. Herein, we report a universal, eco-friendly, facile and rapid synthesis of various nano-metals encapsulated by ultrathin carbon shells, significantly with a remarkable deep-UV LSPR characteristic, via a liquid-phase laser fabrication method. Firstly, a new generation of the laser ablation in liquid (LAL) method has been developed with an emphasis on the elaborate selection of solvents to generate ultrathin carbon shells, and hence to stabilize the formed metal nanocrystals. As a result, a series of metal@carbon nanoparticles (NPs), including Cr@C, Ti@C, Fe@C, V@C, Al@C, Sn@C, Mn@C and Pd@C, can be fabricated by this modified LAL method. Interestingly, these NPs exhibit LSPR peaks in the range of 200-330 nm, which are very rare for localized surface plasmon resonance. Consequently, the UV plasmonic effects of these metal@carbon NPs were demonstrated both by the observed enhancement in UV photoluminescence (PL) from the carbon nanoshells and by the improvement of the photo-responsivity of UV GaN photodetectors. This work could provide a universal method for carbon shelled metal NPs and expand plasmonics into the D-UV waveband.

  13. SPATIALLY EXTENDED 21 cm SIGNAL FROM STRONGLY CLUSTERED UV AND X-RAY SOURCES IN THE EARLY UNIVERSE

    SciTech Connect

    Ahn, Kyungjin; Xu, Hao; Norman, Michael L.

    2015-03-20

    We present our prediction for the local 21 cm differential brightness temperature (δT{sub b}) from a set of strongly clustered sources of Population III (Pop III) and II (Pop II) objects in the early universe, by a numerical simulation of their formation and radiative feedback. These objects are located inside a highly biased environment, which is a rare, high-density peak (“Rarepeak”) extending to ∼7 comoving Mpc. We study the impact of ultraviolet and X-ray photons on the intergalactic medium (IGM) and the resulting δT{sub b}, when Pop III stars are assumed to emit X-ray photons by forming X-ray binaries verymore » efficiently. We parameterize the rest-frame spectral energy distribution of X-ray photons, which regulates X-ray photon-trapping, IGM-heating, secondary Lyα pumping and the resulting morphology of δT{sub b}. A combination of emission (δT{sub b} > 0) and absorption (δT{sub b} < 0) regions appears in varying amplitudes and angular scales. The boost of the signal by the high-density environment (δ ∼ 0.64) and on a relatively large scale combines to make Rarepeak a discernible, spatially extended (θ ∼ 10′) object for 21 cm observation at 13 ≲ z ≲ 17, which is found to be detectable as a single object by SKA with integration time of ∼1000 hr. Power spectrum analysis by some of the SKA precursors (Low Frequency Array, Murchison Widefield Array, Precision Array for Probing the Epoch of Reionization) of such rare peaks is found to be difficult due to the rarity of these peaks, and the contribution only by these rare peaks to the total power spectrum remains subdominant compared to that by all astrophysical sources.« less

  14. Modellierung dreidimensionaler Strahlungsfelder im frühen Universum %t Modelling three dimensional radiation fields in the early universe

    NASA Astrophysics Data System (ADS)

    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.

  15. The Early Development of the Open University: Report of the Vice-Chancellor January 1969-December 1970.

    ERIC Educational Resources Information Center

    Open Univ., Walton, Bletchley, Bucks (England).

    This report concerns the extablishment and development of the British Open University. Contents include the descriptions of: the development of the institution; staffing the open university; development of the Milton Keynes Campus; undergraduate course development; regional organization; demand for open university courses; development, production,…

  16. University Extension: The Early Years in the United States 1885-1915. NUEA-ACT Series on Continuing Education.

    ERIC Educational Resources Information Center

    Woytanowitz, George M.

    University extension arose in England during the late 1860s as an adult education movement providing university-style education for all people. In the United States in the 1880s, university extension was only the latest in a series of ventures in schooling for adults. Adult education had existed in the colonial period, but the first widespread…

  17. Bolide impacts and the oxidation state of carbon in the earth's early atmosphere

    NASA Technical Reports Server (NTRS)

    Kasting, James F.

    1990-01-01

    A one-dimensional photochemical model was used to examine the effect of bolide impacts on the oxidation state of earth's primitive atmosphere. The impact rate should have been high prior to 3.8 Ga before present, based on evidence derived from the moon. Impacts of comets or carbonaceous asteroids should have enhanced the atmospheric CO/CO2 ratio by bringing in CO ice and/or organic carbon that can be oxidized to CO in the impact plume. Ordinary chondritic impactors would contain elemental iron that could have reacted with ambient CO2 to give CO. Nitric oxide (NO) should also have been produced by reaction between ambient CO2 and N2 in the hot impact plumes. High NO concentrations increase the atmospheric CO/CO2 ratio by increasing the rainout rate of oxidized gases. According to the model, atmospheric CO/CO2 ratios of unity or greater are possible during the first several hundred million years of earth's history, provided that dissolved CO was not rapidly oxidized to bicarbonate in the ocean.

  18. Understanding the Early Transition Needs of Diverse Commencing University Students in a Health Faculty: Informing Effective Intervention Practices

    ERIC Educational Resources Information Center

    Wilson, Keithia L.; Murphy, Karen A.; Pearson, Andrew G.; Wallace, Barbara M.; Reher, Vanessa G. S.; Buys, Nicholas

    2016-01-01

    The engagement and retention of commencing students is a longstanding issue in higher education, particularly with the implementation of the widening student participation agenda. The early weeks of the first semester are especially critical to student engagement and early attrition. This study investigated the perceived early transition needs of…

  19. Carbon isotopic variation in ureilites: Evidence for an early, volatile-rich Inner Solar System

    NASA Astrophysics Data System (ADS)

    Barrat, Jean-Alix; Sansjofre, Pierre; Yamaguchi, Akira; Greenwood, Richard C.; Gillet, Philippe

    2017-11-01

    We analyzed the C isotopic compositions of 32 unbrecciated ureilites, which represent mantle debris from a now disrupted, C-rich, differentiated body. The δ13C values of their C fractions range from -8.48 to +0.11‰. The correlations obtained between δ13C, δ18O and Δ17O values and the compositions of the olivine cores, indicate that the ureilite parent body (UPB) accreted from two reservoirs displaying distinct O and C isotopic compositions. The range of Fe/Mg ratios shown by its mantle was not the result of melting processes involving reduction with C ("smelting"), but was chiefly inherited from the mixing of these two components. Because smelting reactions are pressure-dependent, this result has strong implications for the size of the UPB, and points to a large parent body, at least 690 km in diameter. It demonstrates that C-rich primitive matter distinct from that represented by carbonaceous chondrites was present in some areas of the early inner Solar System, and could have contributed to the growth of the terrestrial planets. We speculate that differentiated, C-rich bodies, or debris produced by their disruption, were an additional source of volatiles during the later accretion stages of the rocky planets, including Earth.

  20. Thallium isotope evidence for a permanent increase in marine organic carbon export in the early Eocene

    USGS Publications Warehouse

    Nielsen, S.G.; Mar-Gerrison, S.; Gannoun, A.; LaRowe, D.; Klemm, V.; Halliday, A.N.; Burton, K.W.; Hein, J.R.

    2009-01-01

    The first high resolution thallium (Tl) isotope records in two ferromanganese crusts (Fe-Mn crusts), CD29 and D11 from the Pacific Ocean are presented. The crusts record pronounced but systematic changes in 205Tl/203Tl that are unlikely to reflect diagenetic overprinting or changes in isotope fractionation between seawater and Fe-Mn crusts. It appears more likely that the Fe-Mn crusts track the Tl isotope composition of seawater over time. The present-day oceanic residence time of Tl is estimated to be about 20,000??yr, such that the isotopic composition should reflect ocean-wide events. New and published Os isotope data are used to construct age models for these crusts that are consistent with each other and significantly different from previous age models. Application of these age models reveals that the Tl isotope composition of seawater changed systematically between ~ 55??Ma and ~ 45??Ma. Using a simple box model it is shown that the present day Tl isotope composition of seawater depends almost exclusively on the ratio between the two principal output fluxes of marine Tl. These fluxes are the rate of removal of Tl from seawater via scavenging by authigenic Fe-Mn oxyhydroxide precipitation and the uptake rate of Tl during low temperature alteration of oceanic crust. It is highly unlikely that the latter has changed greatly. Therefore, assuming that the marine Tl budget has also not changed significantly during the Cenozoic, the low 205Tl/203Tl during the Paleocene is best explained by a more than four-fold higher sequestration of Tl by Fe-Mn oxyhydroxides compared with at the present day. The calculated Cenozoic Tl isotopic seawater curve displays a striking similarity to that of S, providing evidence that both systems may have responded to the same change in the marine environment. A plausible explanation is a marked and permanent increase in organic carbon export from ~ 55??Ma to ~ 45??Ma, which led to higher pyrite burial rates and a significantly reduced

  1. Carbon nanotube and nanofiber exposure and sputum and blood biomarkers of early effect among U.S. workers.

    PubMed

    Beard, John D; Erdely, Aaron; Dahm, Matthew M; de Perio, Marie A; Birch, M Eileen; Evans, Douglas E; Fernback, Joseph E; Eye, Tracy; Kodali, Vamsi; Mercer, Robert R; Bertke, Stephen J; Schubauer-Berigan, Mary K

    2018-07-01

    Carbon nanotubes and nanofibers (CNT/F) are increasingly used for diverse applications. Although animal studies suggest CNT/F exposure may cause deleterious health effects, human epidemiological studies have typically been small, confined to single workplaces, and limited in exposure assessment. We conducted an industrywide cross-sectional epidemiological study of 108 workers from 12 U.S. sites to evaluate associations between occupational CNT/F exposure and sputum and blood biomarkers of early effect. We assessed CNT/F exposure via personal breathing zone, filter-based air sampling to measure background-corrected elemental carbon (EC) (a CNT/F marker) mass and microscopy-based CNT/F structure count concentrations. We measured 36 sputum and 37 blood biomarkers. We used factor analyses with varimax rotation to derive factors among sputum and blood biomarkers separately. We used linear, Tobit, and unconditional logistic regression models to adjust for potential confounders and evaluate associations between CNT/F exposure and individual biomarkers and derived factors. We derived three sputum and nine blood biomarker factors that explained 78% and 67%, respectively, of the variation. After adjusting for potential confounders, inhalable EC and total inhalable CNT/F structures were associated with the most sputum and blood biomarkers, respectively. Biomarkers associated with at least three CNT/F metrics were 72 kDa type IV collagenase/matrix metalloproteinase-2 (MMP-2), interleukin-18, glutathione peroxidase (GPx), myeloperoxidase, and superoxide dismutase (SOD) in sputum and MMP-2, matrix metalloproteinase-9, metalloproteinase inhibitor 1/tissue inhibitor of metalloproteinases 1, 8-hydroxy-2'-deoxyguanosine, GPx, SOD, endothelin-1, fibrinogen, intercellular adhesion molecule 1, vascular cell adhesion protein 1, and von Willebrand factor in blood, although directions of associations were not always as expected. Inhalable rather than respirable CNT/F was more

  2. The contribution of leaching to the rapid release of nutrients and carbon in the early decay of wetland vegetation

    USGS Publications Warehouse

    Davis, S. E.; Childers, D.L.; Noe, G.B.

    2006-01-01

    Our goal was to quantify the coupled process of litter turnover and leaching as a source of nutrients and fixed carbon in oligotrophic, nutrient-limited wetlands. We conducted poisoned and non-poisoned incubations of leaf material from four different perennial wetland plants (Eleocharis spp., Cladium jamaicense, Rhizophora mangle and Spartina alterniflora) collected from different oligotrophic freshwater and estuarine wetland settings. Total phosphorus (TP) release from the P-limited Everglades plant species (Eleocharis spp., C. jamaicense and R. mangle) was much lower than TP release by the salt marsh plant S. alterniflora from N-limited North Inlet (SC). For most species and sampling times, total organic carbon (TOC) and TP leaching losses were much greater in poisoned than non-poisoned treatments, likely as a result of epiphytic microbial activity. Therefore, a substantial portion of the C and P leached from these wetland plant species was bio-available to microbial communities. Even the microbes associated with S. alterniflora from N-limited North Inlet showed indications of P-limitation early in the leaching process, as P was removed from the water column. Leaves of R. mangle released much more TOC per gram of litter than the other species, likely contributing to the greater waterborne [DOC] observed by others in the mangrove ecotone of Everglades National Park. Between the two freshwater Everglades plants, C. jamaicense leached nearly twice as much P than Eleocharis spp. In scaling this to the landscape level, our observed leaching losses combined with higher litter production of C. jamaicense compared to Eleocharis spp. resulted in a substantially greater P leaching from plant litter to the water column and epiphytic microbes. In conclusion, leaching of fresh plant litter can be an important autochthonous source of nutrients in freshwater and estuarine wetland ecosystems. ?? Springer 2006.

  3. [Value of early-stage cerebral oxygen utilization coefficient in predicting delayed encephalopathy after acute carbon monoxide poisoning].

    PubMed

    Liu, Q; Li, W; Li, N; Xiao, Q M; He, J Q; Wang, W Z; Qi, H N; Wang, P

    2017-05-20

    Objective: To investigate the dynamic change in cerebral oxygen utilization coefficient (O(2)UCc) in the early stage of acute severe carbon monoxide poisoning (ASCMP) and its value in predicting delayed encephalopathy after acute carbon monoxide poisoning (DEACMP) . Methods: A prospective observational study was conducted for patients with ASCMP who were admitted to our hospital from November 2013 to March 2016, and their baseline features and physiological parameters were recorded. Observation ended at two months after acute poisoning; according to the presence or absence of DEACMP, the patients were divided into DEACMP group with 21 patients and non-DEACMP group with 64 patients. The change in O(2)UCc was monitored on admission and at 6, 24, 48, and 72 hours. Spearman correlation was used to investigate the correlation between O(2)UCc and Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and the receiver operating characteristic (ROC) curve was used to evaluate the accuracy of O(2)UCc in predicting DEACMP. Results: Both groups had a significant increase in O(2)UCc on admission, and the DEACMP group had a significantly greater increase than the non-DEACMP group (52.57%±9.30% vs 41.46±%6.37%, P <0.05) . Then both groups tended to have a reduction in O(2)UCc, and the DEACMP group had a significantly higher O(2)UCc than the non-DEACMP group at 6, 24, and 48 hours (47.40%±7.92%, 39.38%±8.01%, and 32.29%±6.31% vs 34.51%±7.89%, 28.79%±5.4%, and 27.72%±5.46%, P <0.05) . On admission and at 6, 24, and 48 hours, O2UCc was positively correlated with APACHE II score ( r =0.304, 0.398, 0.426, and 0.300, P =0.005, 0.000, 0.000, and 0.005) . The ROC curve showed that O(2)UCc had a value in predicting DEACMP on admission and at 6, 24, and 48 hours, and 6-hour O2UCc had the highest predictive value with an area under the ROC curve of 0.870 (95% confidence interval 0.794-0.947, P <0.05) . Conclusion: The dynamic change in O(2)UCc has a reference value in

  4. Using Triple Oxygen Isotope Analyses of Biogenic Carbonate to Reconstruct Early Triassic Ocean Oxygen Isotopic Values and Temperatures

    NASA Astrophysics Data System (ADS)

    Gibbons, J. A.; Sharp, Z. D.; Atudorei, V.

    2017-12-01

    The calcite-water triple oxygen isotope fractionation is used to determine isotopic equilibrium and ancient ocean oxygen isotopic values and temperatures. Unlike conventional δ18O analysis where the formation water's isotopic value is assumed, paired δ17O-δ18O measurements allow for the water's isotopic composition to be calculated because there is only one unique solution for equilibrium fractionation using Δ17O-δ18O values (where Δ17O=δ17O-0.528δ18O). To a first approximation, the calcite-water equilibrium fractionation factor, θ (where θ=ln17α/ln18α), varies with temperature by 0.00001/°. The calcite-water equilibrium fractionation line was determined at two temperatures, 30° and 0°, by using modern carbonate samples that formed in ocean water with a δ18O value of 0‰. The θ values for the 30° and 0° samples are 0.52515 and 0.52486, respectively. Oxygen values were measured using complete fluorination in nickel tubes with BrF5 as the reaction reagent. We calibrated all oxygen values to the SMOW-SLAP scale by measuring SMOW, SLAP, San Carlos olivine, NBS-18, NBS-19, and PDB. The triple oxygen isotope calcite-water equilibrium fractionation line was applied to well preserved Early Triassic ammonite shells from the Western United States. Based on paired δ17O-δ18O measurements, the samples did not form in equilibrium with an ice-free ocean with an oxygen isotopic value of -1‰ or the modern ocean value of 0‰. Assuming the calcite is still primary and formed in equilibrium with the ocean water, our data indicate that the δ18O value of the ocean in the early Triassic was 3-5‰ lower than modern. Samples from the Smithian thermal maximum formed in water 10° warmer than samples from after the thermal maximum. Paired δ17O-δ18O measurements of pristine ancient carbonates may provide a better understanding of past ocean conditions during climate change events.

  5. Serum neuron-specific enolase as an early predictor of delayed neuropsychiatric sequelae in patients with acute carbon monoxide poisoning.

    PubMed

    Cha, Y S; Kim, H; Do, H H; Kim, H I; Kim, O H; Cha, K-C; Lee, K H; Hwang, S O

    2018-03-01

    Delayed onset of neuropsychiatric symptoms after apparent recovery from acute carbon monoxide (CO) poisoning has been described as delayed neuropsychiatric sequelae (DNS). To date, there have been no studies on the utility of serum neuron-specific enolase (NSE), a marker of neuronal cell damage, as a predictive marker of DNS in acute CO poisoning. This retrospective observational study was performed on adult patients with acute CO poisoning consecutively treated over a 9-month period. Serum NSE was measured after emergency department arrival, and patients were divided into two groups. The DNS group comprised patients with delayed sequelae, while the non-DNS group included patients with none of these sequelae. A total of 98 patients with acute CO poisoning were enrolled in this study. DNS developed in eight patients. The median NSE value was significantly higher in the DNS group than in the non-DNS group. There was a statistical difference between the non-DNS group and the DNS group in terms of CO exposure time, Glasgow Coma Scale (GCS), loss of consciousness, creatinine kinase, and troponin I. GCS and NSE were the early predictors of development of DNS. The area under the curve according to the receiver operating characteristic curves of GCS, serum NSE, and GCS combined with serum NSE were 0.922, 0.836, and 0.969, respectively. In conclusion, initial GCS and NSE served as early predictors of development of DNS. Also, NSE might be a useful additional parameter that could improve the prediction accuracy of initial GCS.

  6. Nannofossil carbonate fluxes during the Early Cretaceous: Phytoplankton response to nutrification episodes, atmospheric CO2, and anoxia

    NASA Astrophysics Data System (ADS)

    Erba, Elisabetta; Tremolada, Fabrizio

    2004-03-01

    Greenhouse episodes during the Valanginian and Aptian correlate with major perturbations in the C cycle and in marine ecosystems, carbonate crises, and widespread deposition of Corg-rich black shales. Quantitative analyses of nannofossil micrite were conducted on continuous pelagic sections from the Southern Alps (northern Italy), where high-resolution integrated stratigraphy allows precise dating of Early Cretaceous geological events. Rock-forming calcareous nannofloras were quantified in smear slides and thin sections to obtain relative and absolute abundances and paleofluxes that are interpreted as the response of calcareous phytoplankton to global changes in the ocean-atmosphere system. Increased rates of volcanism during the formation of Ontong Java and Manihiki Plateaus and the Paranà-Etendeka large igneous province (LIP) are proposed to have caused the geological responses associated with early Aptian oceanic anoxic event (OAE) 1a and the Valanginian event, respectively. Calcareous nannofloras reacted to the new conditions of higher pCO2 and fertility by drastically reducing calcification. The Valanginian event is marked by a 65% reduction in nannofossil paleofluxes that would correspond to a 2-3 times increase in pCO2 during formation of the Paranà-Endenteka LIP. A 90% reduction in nannofossil paleofluxes, which occurred in a 1.5 myr-long interval leading into OAE1a, is interpreted as the result of a 3-6 times increase in pCO2 produced by emplacement of the giant Ontong Java and Manihiki Plateaus. High pCO2 was balanced back by an accelerated biological pump during the Valanginian episode, but not during OAE1a, suggesting persisting high levels of pCO2 in the late Aptian and/or the inability of calcareous phytoplankton to absorb excess pCO2 above threshold values.

  7. Exploring Processes and Outcomes of Wireless Internet in Higher Education: A Case Study of a University's Early Experience

    ERIC Educational Resources Information Center

    Lee, Lisa

    2007-01-01

    Many universities in the UK have recently started offering their staff and students free wireless Internet access through Wireless Local Area Network (WLAN) technologies, such as Wi-Fi. Based on a small empirical study of WLAN deployment in a university setting, the article explores adoption processes of the new technology by both the organisation…

  8. Developing and Supporting Early Childhood Teacher Leaders: A Leadership Project Connecting University, Community and Public School Resources

    ERIC Educational Resources Information Center

    Maxfield, C. Robert; Ricks-Doneen, Julie; Klocko, Barbara A.; Sturges, Lisa

    2011-01-01

    The empowerment of early childhood educators as teacher leaders can translate into effective instructional practices that promote children's development. This paper aims to broaden the discussion about the relationship between early childhood educators and their traditional K-12 counterparts. We seek to present a wider exploration of what it takes…

  9. Building as We Go: Secondary Schools, Community Colleges, and Universities in Partnership--The Early College High School Initiative

    ERIC Educational Resources Information Center

    Bush, V. Barbara

    2017-01-01

    The purpose of this study was to examine the perceptions of key informants about the processes of institutional change and collaboration involved in the development of three early college high schools (ECHS)s over a 4-year period. The 15 study participants were members of early college high school councils and included high school principals,…

  10. A Giant Arctic Freshwater Pond at the end of the Early Eocene; Implications for Ocean Heat Transport and Carbon Cycling

    NASA Astrophysics Data System (ADS)

    Brinkhuis, H.; Schouten, S.; Collinson, M. E.; Sluijs, A.; Sinninghe-Damste, J. S.; Dickens, G. R.; Huber, M.; Cronin, T. M.; Bujak, J. P.; Stein, R.; Eldrett, J. S.; Harding, I. C.; Sangiorgi, F.

    2005-12-01

    In the last decades remains of the free-floating, fresh water fern Azolla have been found in unusually high abundances in basal middle Eocene (~48.5 Ma) marine sediments deposited in all Nordic seas. While generally taken to signal some `freshwater input', their source and significance were not determined. Through palynological and organic geochemical analyses of unique cores obtained from unprecedented Arctic Ocean drilling (IODP 302 - ACEX) we show that the brackish surface conditions that prevailed in the Arctic Ocean through the late Paleocene and early Eocene culminated in the deposition of laminated organic rich deposits yielding huge amounts of remains of Azolla. This, plus e.g., low diversity dinoflagellate assemblages, and concomitant low BIT values, indicates in-situ Azolla growth, and that the surface of the Arctic Ocean episodically resembled a giant fresh water pond over an interval altogether lasting ~800,000 years. The Arctic Basin thus constituted the main source of the freshwater pulses found elsewhere, reaching as far south as the southern North Sea.TEX86-derived surface temperatures were 13-14°C before and after the Azolla interval and only 10°C during the event, which may be related to obstruction of pole ward ocean heat transport and/or increased carbon burial.

  11. Salinity of the Early and Middle Eocene Arctic Ocean From Oxygen Isotope Analysis of Fish Bone Carbonate

    NASA Astrophysics Data System (ADS)

    Waddell, L. M.; Moore, T. C.

    2006-12-01

    Plate tectonic reconstructions indicate that the Arctic was largely isolated from the world ocean during the early and middle Eocene, with exchange limited to shallow, and possibly intermittent, connections to the North Atlantic and Tethys (via the Turgay Strait). Relative isolation, combined with an intensification of the hydrologic cycle under an Eocene greenhouse climate, is suspected to have led to the development of a low- salinity surface water layer in the Arctic that could have affected deep and intermediate convection in the North Atlantic. Sediment cores recently recovered from the Lomonosov Ridge by the IODP 302 Arctic Coring Expedition (ACEX) allow for the first assessment of the salinity of the Arctic Ocean during the early and middle Eocene. Stable isotope analysis performed on the structural carbonate of fish bone apatite from ~30 samples between the ages of ~55 and ~44 myr yielded δ18O values between -6.84‰ and -2.96‰ VPDB, with a mean value of -4.89‰. From the δ18O values we calculate that the Arctic Ocean was probably brackish during most of the early and middle Eocene, with an average salinity of 19 to 24‰. Negative excursions in the δ18O record (<-6‰) indicate three events during which the salinity of the Arctic surface waters was severely lowered: the Paleocene Eocene Thermal Maximum (PETM), the Azolla event at ~49 Ma, and a third previously unidentified event at ~46 Ma. During the PETM, low salinities developed under conditions of increased regional precipitation and runoff associated with extreme high latitude warmth and possible tectonic uplift in the North Atlantic. During the other two low-salinity events, sea level was lowered by ~20-30 m, implying a possible severing of Arctic connections to the world ocean. The most positive δ18O value (-2.96‰) occurs at ~45 Ma, the age of the youngest dropstone discovered in the ACEX sediments, and may therefore correspond to a climatic cooling rather than a high salinity event.

  12. Comparison of Efficacy of Carbon Dioxide (CO2) Laser with Cutting Diathermy in Surgical Excision of Early Carcinoma Tongue.

    PubMed

    Rashid, Muhammad; Hashmi, Muhammad Ali; Maqbool, Shahzad; Dastigir, Majid

    2015-10-01

    To compare the efficacy of carbon dioxide (CO(2)) laser with cutting diathermy as a cutting device in surgical excision of early carcinoma tongue. Experimental study. Combined Military Hospital (CMH), Rawalpindi and CMH, Lahore, from July 2008 to July 2011. Twenty two biopsy proven cases of T(1) and early T(2) squamous cell carcinoma of tongue were divided in two equal groups of 11 each labeled as A and B. Tumor was excised by CO(2) laser in group A while cutting diathermy was done in group B. For both groups tumor excision time, per-operative blood loss, postoperative oral swelling and pain was recorded. Excision time of tumor was assessed in minutes and amount of blood loss in milliliters till complete hemostasis after removal of primary tumor. Postoperatively patients were assessed on 12 hourly basis for 48 hours for pain. Pain was analyzed on visual analogue score 1 - 10. Oral swelling was assessed once after 24 hours and labeled as mild, moderate and severe. Independent sample t-test was applied for analysis of excision time, postoperative pain and per-operative blood loss for both groups. Postoperative swelling was analyzed using Fisher's exact test. P-value of < 0.05 was considered significant. The mean age at diagnosis in group A was 49.36 ± 5.27 years, while in group B patients had mean age of 50.73 ± 8.13 years. In group A, 4/11 (36.3%) patients were having tumor stage T(1) while 7/11 (63.6%) had T(2) stage tumor. In group B, 5/11 (45.4%) were having T1 and 6/11 (54.5%) were having stage T(2) tumor. Excision time was significantly shorter for group B (p=0.003), but group A had less postoperative pain (p=0.001), less per-operative blood loss (p=0.001) and less postoperative oral swelling (p=0.021). Early carcinoma tongue is better removed by laser than electrocautery in terms of postoperative morbidity, per-operative blood loss, postoperative pain and oral swelling.

  13. Representing massive gravitons, as a way to quantify early universe magnetic field contributions to space-time, created by non linear electrodynamics

    SciTech Connect

    Beckwith, Andrew Walcott, E-mail: Rwill9955b@gmail.com

    We review a relationship between cosmological vacuum energy and massive gravitons as given by Garattini and also the nonlinear electrodynamics of Camara et.al (2004) for a non singular universe and NLED. . In evaluating the Garattini result, we find that having the scale factor close to zero due to a given magnetic field value in, an early universe magnetic field affects how we would interpret Garattini’s linkage of the ‘cosmological constant’ value and non zero graviton mass.. We close as to how these initial conditions affect the issue of an early universe initial pressure and its experimental similarities and differencesmore » with results by Corda and Questa as to negative pressure at the surface of a star. Note, that in theDupays et.al. article , the star in question is rapidly spinning, which is not. assumed in the Camara et.al article , for an early universe. Also, Corda and Questa do not assume a spinning star. We conclude with a comparison between the Lagrangian Dupays and other authors bring up for non linear electrodynamics which is for rapidly spinning neutron stars , and a linkage between the Goldstone theorem and NLED. Our conclusion is for generalizing results seen in the Dupays neutron star Lagrangian with conditions which may confirm C. A. Escobar and L. F. Urrutia’s work on the Goldstone theorem and non linear electrodynamics, for some future projects we have in mind. If the universe does not spin, then we will stick with the density analogy given by adapting density as proportional to one over the fourth power of the minimum value of the scale factor as computed by adaptation of the Camara et.al.(2004) theory for non spinning universes. What may happen is that the Camara (2004) density and Quintessential density are both simultaneously satisfied, which would put additional restrictions on the magnetic field, which is one of our considerations, regardless if a universe spins, akin to spinning neutron stars. The spinning universe though

  14. Community replacement instead of drowning: Evolution of proto-North Atlantic carbonate-platform production in the run-up to of the Early Aptian OAE1a

    NASA Astrophysics Data System (ADS)

    Huck, Stefan; Stein, Melody; Adatte, Thierry; Föllmi, Karl B.; Immenhauser, Adrian; Heimhofer, Ulrich

    2014-05-01

    In the proto-North Atlantic realm (Lusitanian Basin, Portugal), carbonate platform production witnessed a major biotic turnover during the Early Aptian. Here, Urgonian-type rudist-nerinid dominated limestones were replaced by an orbitolinid-rich, oyster and serpulid-bearing marly facies. Integrated biostratigraphic-chemostratigraphic studies (Burla et al., 2008; Huck et al., 2012) provided evidence that this change coincides with the Early Aptian carbonate platform drowning episode in the run-up of oceanic anoxic event (OAE) 1a (transition D. forbesi to D. deshayesi ammonite zones), which has been recorded, from many localities in the Tethyan Ocean (Godet, 2013). Unlike Helvetic and Arabian carbonate platforms, which are characterised by a punctuated mass occurrence of orbitolinids marking the onset of the Aptian (Rawil and Hawar members, respectively), orbitolinids are an abundant constituent of the proto-North Atlantic carbonate platform community from the Late Barremian onwards. Orbitolinid-rich packstones and marls showing mass-occurrences of orbitolinids indicate repeated short-term installation of specific environmental conditions (eutrophication and/or deepening). In order to critically assess the influence of regional palaeoenvironmental against global palaeoclimatic and palaeoceanographic changes on the Proto-North Atlantic carbonate platform evolution, several outcrop successions in the Lusitanian Basin covering the critical interval have been investigated in detail with regard to facies and petrographic characteristics and geochemical (C-/O-isotopes, P content, bulk-rock and clay mineralogy,) inventory. The aims of the present study are three-fold: (1) to characterise proto-North Atlantic Lower Aptian shallow-water carbonates with respect to diagenetic history, microfacies, and distribution of fossils useful for the analysis of palaeoenvironments (corals, rudists and orbitolinids); (2) to evaluate the influence of sea-level and humidity changes

  15. Temperature and composition of carbonate cements record early structural control on cementation in a nascent deformation band fault zone: Moab Fault, Utah, USA

    NASA Astrophysics Data System (ADS)

    Hodson, Keith R.; Crider, Juliet G.; Huntington, Katharine W.

    2016-10-01

    Fluid-driven cementation and diagenesis within fault zones can influence host rock permeability and rheology, affecting subsequent fluid migration and rock strength. However, there are few constraints on the feedbacks between diagenetic conditions and structural deformation. We investigate the cementation history of a fault-intersection zone on the Moab Fault, a well-studied fault system within the exhumed reservoir rocks of the Paradox Basin, Utah, USA. The fault zone hosts brittle structures recording different stages of deformation, including joints and two types of deformation bands. Using stable isotopes of carbon and oxygen, clumped isotope thermometry, and cathodoluminescence, we identify distinct source fluid compositions for the carbonate cements within the fault damage zone. Each source fluid is associated with different carbonate precipitation temperatures, luminescence characteristics, and styles of structural deformation. Luminescent carbonates appear to be derived from meteoric waters mixing with an organic-rich or magmatic carbon source. These cements have warm precipitation temperatures and are closely associated with jointing, capitalizing on increases in permeability associated with fracturing during faulting and subsequent exhumation. Earlier-formed non-luminescent carbonates have source fluid compositions similar to marine waters, low precipitation temperatures, and are closely associated with deformation bands. The deformation bands formed at shallow depths very early in the burial history, preconditioning the rock for fracturing and associated increases in permeability. Carbonate clumped isotope temperatures allow us to associate structural and diagenetic features with burial history, revealing that structural controls on fluid distribution are established early in the evolution of the host rock and fault zone, before the onset of major displacement.

  16. Zooming in on star formation in the brightest galaxies of the early Universe discovered with the Planck and Herschel satellites

    NASA Astrophysics Data System (ADS)

    Canameras, Raoul

    2016-09-01

    Strongly gravitationally lensed galaxies offer an outstanding opportunity to characterize the most intensely star-forming galaxies in the high-redshift universe. In the most extreme cases, one can probe the mechanisms that underlie the intense star formation on the scales of individual star-forming regions. This requires very fortuitous gravitational lensing configurations offering magnification factors >>10, which are particularly rare toward the high-redshift dusty star-forming galaxies. The Planck's Dusty GEMS (Gravitationally Enhanced subMillimeter Sources) sample contains eleven of the brightest high-redshift galaxies discovered with the Planck submillimeter all-sky survey, with flux densities between 300 and 1000 mJy at 350 microns, factors of a few brighter than the majority of lensed sources previously discovered with other surveys. Six of them are above the 90% completeness limit of the Planck Catalog of Compact Sources (PCCS), suggesting that they are among the brightest high-redshift sources on the sky selected by their active star formation. This thesis comes within the framework of the extensive multi-wavelength follow-up programme designed to determine the overall properties of the high-redshift sources and to probe the lensing configurations. Firstly, to characterize the intervening lensing structures and calculate lensing models, I use optical and near/mid-infrared imaging and spectroscopy. I deduce that our eleven GEMS are aligned with intervening matter overdensities at intermediate redshift, either massive isolated galaxies or galaxy groups and clusters. The foreground sources exhibit evolved stellar populations of a few giga years, characteristic of early-type galaxies. Moreover, the first detailed models of the light deflection toward the GEMS suggest magnification factors systematically >10, and >20 for some lines-of-sight. Secondly, we observe the GEMS in the far-infrared and sub-millimeter domains in order to characterize the background

  17. Early diagenetic dolomitization and dedolomitization of Late Jurassic and earliest Cretaceous platform carbonates: A case study from the Jura Mountains (NW Switzerland, E France)

    NASA Astrophysics Data System (ADS)

    Rameil, Niels

    2008-12-01

    Early diagenetic dolomitization is a common feature in cyclic shallow-water carbonates throughout the geologic record. After their generation, dolomites may be subject to dedolomitization (re-calcification of dolomites), e.g. by contact with meteoric water during emersion. These patterns of dolomitization and subsequent dedolomitization frequently play a key role in unravelling the development and history of a carbonate platform. On the basis of excellent outcrops, detailed logging and sampling and integrating sedimentological work, high-resolution sequence stratigraphic interpretations, and isotope analyses (O, C), conceptual models on early diagenetic dolomitization and dedolomitization and their underlying mechanisms were developed for the Upper Jurassic / Lower Cretaceous Jura platform in north-western Switzerland and eastern France. Three different types of early diagenetic dolomites and two types of dedolomites were observed. Each is defined by a distinct petrographic/isotopic signature and a distinct spatial distribution pattern. Different types of dolomites are interpreted to have been formed by different mechanisms, such as shallow seepage reflux, evaporation on tidal flats, and microbially mediated selective dolomitization of burrows. Depending on the type of dolomite, sea water with normal marine to slightly enhanced salinities is proposed as dolomitizing fluid. Based on the data obtained, the main volume of dolomite was precipitated by a reflux mechanism that was switched on and off by high-frequency sea-level changes. It appears, however, that more than one dolomitization mechanism was active (pene)contemporaneously or several processes alternated in time. During early diagenesis, percolating meteoric waters obviously played an important role in the dedolomitization of carbonate rocks that underlie exposure surfaces. Cyclostratigraphic interpretation of the sedimentary succession allows for estimates on the timing of early diagenetic (de

  18. Prognostic Value of Venous to Arterial Carbon Dioxide Difference during Early Resuscitation in Critically Ill Patients with Septic Shock.

    PubMed

    Helmy, Tamer Abdallah; El-Reweny, Ehab Mahmoud; Ghazy, Farahat Gomaa

    2017-09-01

    The partial pressure of venous to arterial carbon dioxide gradient (PCO 2 gap) is considered as an alternative marker of tissue hypoperfusion and has been used to guide treatment for shock. The aim of this study was to investigate the prognostic value of venous-to-arterial carbon dioxide difference during early resuscitation of patients with septic shock and compared it with that of lactate clearance and Acute Physiology and Chronic Health Evaluation II (APACHE-II) score. Forty patients admitted to one Intensive Care Unit were enrolled. APACHE-II score was calculated on admission. An arterial blood gas, central venous, and lactate samples were obtained on admission and after 6 h, and lactate clearance was calculated. Patients were classified retrospectively into Group I (survivors) and Group II (nonsurvivors). Pv-aCO 2 difference in the two groups was evaluated. Data were fed to the computer and analyzed using IBM SPSS software package version 20.0. At T0, Group II showed high PCO 2 gap (8.37 ± 1.36 mmHg) than Group I (7.55 ± 0.95 mmHg) with statistically significant difference ( P = 0.030). While at T6, Group II showed higher PCO 2 gap (9.48 ± 1.47 mmHg) with statistically significant difference ( P < 0.001) and higher mean lactate values (62.71 ± 23.66 mg/dl) with statistically significant difference ( P < 0.001) than Group I where PCO 2 gap and mean lactate values became much lower, 5.91 ± 1.12 mmHg and 33.61 ± 5.80 mg mg/dl, respectively. Group I showed higher lactate clearance (25.42 ± 6.79%) with statistically significant difference ( P < 0.001) than Group II (-69.40-15.46%). High PCO 2 gap >7.8 mmHg after 6 h from resuscitation of septic shock patients is associated with high mortality.

  19. An Early-Middle Guadalupian (Permian) isotopic record from a mid-oceanic carbonate buildup: Akiyoshi Limestone, Japan

    NASA Astrophysics Data System (ADS)

    Musashi, Masaaki; Isozaki, Yukio; Kawahata, Hodaka

    2010-08-01

    In order to understand the oceanographic changes before the Guadalupian-Lopingian (Permian) boundary mass extinction event, we investigated the isotopic compositions of the inorganic carbon and the oxygen ( δ13C carb and δ18O carb) of the Guadalupian (Middle Permian) shallow marine carbonates deposited on a seamount-top in the superocean Panthalassa. The drilled samples were obtained at Kaerimizu in the Akiyoshi area, SW Japan. We focused on the Roadian-Wordian (Middle Guadalupian) interval that spans over 7 fusuline zones; i.e. the Parafusulina kaerimizuensis Zone ( Pk Z.), Afghanella ozawai Zone ( Ao Z.), Neoschwagerina craticulifera robusta Zone ( Ncr Z.), Verbeekina verbeeki-Afghanella schenki Zone ( Vv-As Z.), Neoschwageina fusiformis Zone ( Nf Z.), Verbeekina verbeeki Zone ( Vv Z.), and Colania douvillei Zone ( Cd Z.), in ascending order. Analytical results showed that the δ13C carb values stayed almost constant around + 3.0‰ PDB in the Pk Z., Ao Z. and the lower half of the Ncr Z., and those in the upper-section gradually decreased down to -2.0‰, of which the lowest was found in the Cd Z. We statistically extracted the samples with presumably better preserved δ13C carb values in the Kaerimizu section ranged between + 0.5 and + 4.0‰ with average values of δ13C carb of + 2.7 ± 1.0‰, on the basis of δ13C carb- δ18O carb characterization. This interval shows a monotonous decrease in δ13C carb values from ca + 4.0‰ to + 2.0‰. This indicates that the primary productivity might be generally high in the Wordian mid-oceanic domain but slightly declined in the Late Wordian. The studied Early-Middle Guadalupian interval is chemostratigraphically correlated with the other mid-Pansalassan paleo-atoll limestone e.g. Iwato Formation in Japan, suggesting that the relatively high δ13C carb (over + 3.0‰) of seawater predominated in shallow mid-superocean during the middle Middle Permian.

  20. Reproducing early Martian atmospheric carbon dioxide partial pressure by modeling the formation of Mg-Fe-Ca carbonate identified in the Comanche rock outcrops on Mars

    NASA Astrophysics Data System (ADS)

    Berk, Wolfgang; Fu, Yunjiao; Ilger, Jan-Michael

    2012-10-01

    The well defined composition of the Comanche rock's carbonate (Magnesite0.62Siderite0.25Calcite0.11Rhodochrosite0.02) and its host rock's composition, dominated by Mg-rich olivine, enable us to reproduce the atmospheric CO2partial pressure that may have triggered the formation of these carbonates. Hydrogeochemical one-dimensional transport modeling reveals that similar aqueous rock alteration conditions (including CO2partial pressure) may have led to the formation of Mg-Fe-Ca carbonate identified in the Comanche rock outcrops (Gusev Crater) and also in the ultramafic rocks exposed in the Nili Fossae region. Hydrogeochemical conditions enabling the formation of Mg-rich solid solution carbonate result from equilibrium species distributions involving (1) ultramafic rocks (ca. 32 wt% olivine; Fo0.72Fa0.28), (2) pure water, and (3) CO2partial pressures of ca. 0.5 to 2.0 bar at water-to-rock ratios of ca. 500 molH2O mol-1rock and ca. 5°C (278 K). Our modeled carbonate composition (Magnesite0.64Siderite0.28Calcite0.08) matches the measured composition of carbonates preserved in the Comanche rocks. Considerably different carbonate compositions are achieved at (1) higher temperature (85°C), (2) water-to-rock ratios considerably higher and lower than 500 mol mol-1 and (3) CO2partial pressures differing from 1.0 bar in the model set up. The Comanche rocks, hosting the carbonate, may have been subjected to long-lasting (>104 to 105 years) aqueous alteration processes triggered by atmospheric CO2partial pressures of ca. 1.0 bar at low temperature. Their outcrop may represent a fragment of the upper layers of an altered olivine-rich rock column, which is characterized by newly formed Mg-Fe-Ca solid solution carbonate, and phyllosilicate-rich alteration assemblages within deeper (unexposed) units.

  1. High-resolution carbonate isotopic study of the Mural Formation (Cerro Pimas section), Sonora, México: Implications for early Albian oceanic anoxic events

    NASA Astrophysics Data System (ADS)

    Madhavaraju, J.; Lee, Yong Il; Scott, R. W.; González-León, C. M.; Jenkyns, H. C.; Saucedo-Samaniego, J. C.; Ramasamy, S.

    2018-03-01

    The 420-m thick stratigraphic section of the Mural Formation that is exposed in the Cerro Pimas area of northern Sonora, Mexico, is composed of limestone lithofacies ranging from bioclastic wackestone to boundstone, whose biota is characterized by low diversity. Prominent age-diagnostic fossils are benthic foraminifera and long-ranging calcareous algae that indicate the Aptian/Albian boundary is close to the base of the Los Coyotes Member. The carbonates of this formation have negative to positive δ13C values (-4.63 to +2.6‰) and highly depleted δ18O values that range from -12.74 to -8.34‰. The absence of correlation between δ13C and δ18O values supports a primary marine origin for the δ13C values of these limestones. The carbon-isotopic curve of the Cerro Pimas stratigraphic section has well-defined δ13C segments (C8 - C15) that compare with published curves of similar age. In the lower part of the early Albian Los Coyotes Member, the presence of OAE 1b is indicated by an increase followed by a decrease in δ13C values, suggesting correlation with the Kilian Event. The middle part of the Los Coyotes Member has a significant negative carbon-isotope excursion correlated with the globally recognizable early Albian Paquier event. Moreover, another significant negative carbon-isotope shift is observed in the upper part of the Los Coyotes Member, which can be correlated with the Leenhardt Event. The occurrence of the Kilian, Paquier and Leenhardt Events (OAE 1b cluster) in the Cerro Pimas stratigraphy confirms the global nature of these early Albian disturbances of the carbon cycle.

  2. Examining early-diagenetic processes as a chief sink for carbonate in the aftermath of the Triassic-Jurassic crisis: Hettangian concretions of Muller Canyon, NV, USA

    NASA Astrophysics Data System (ADS)

    Ritterbush, K. A.; Loyd, S. J.; Corsetti, F. A.; Bottjer, D. J.; Berelson, W.

    2015-12-01

    Tectonic, climate, and biotic changes across the Triassic-Jurassic transition appear to have resulted in a "carbonate gap" in the rock record of many shallow marine environments. Ecological state changes documented in near-shore settings in both Tethys and Panthassa show an earliest Jurassic switch to sponge-dominated biosiliceous sedimentation regimes. The Sunrise Formation exposed in the Gabbs Valley Range of Nevada (USA) records a peculiar juxtaposition of Hettangian carbonate-rich strata that contain demosponge spicules as the primary bioclast. It is unclear 1) why biocalcifiers were not recorded in higher abundance in this near-shore back-arc basin setting; 2) why carbonates formed following a biosiliceous regime; and 3) what the lithology indicates about post-extinction marine geochemical dynamics. Detailed sedimentological, paleontological, and geochemical analyses were applied to a 20-m thick sequence of limestone and chert in the Muller Canyon area, which is the Auxiliary Stratotype for the Triassic/Jurassic boundary. Concretion anatomy, bioclast microfacies, and oxygen and carbon isotopic signatures all indicate the Hettangian limestones are chiefly diagenetic concretions that all formed very shallowly, some essentially at the sediment-water interface. We infer that local bottom waters and/or pore waters were supersaturated with respect to calcium carbonate and that this contributed to widespread concretion sedimentation independent of biomineralization. Ecological incumbency of the demosponge meadows may have been supported by concurrent augmentation of marine silica concentration and this apparently proved inhospitable to re-colonization of benthic biocalcifying macrofauna. Together the biotic and lithologic consequences of the extinction represent million-year scale ecological restructuring and highlight early diagenetic precipitation as a major sink in long-term regional carbonate cycling. Perhaps the widespread 'carbonate gap' is actually a gap in

  3. Isotopically zoned carbonate cements in Early Paleozoic sandstones of the Illinois Basin: δ18O and δ13C records of burial and fluid flow

    NASA Astrophysics Data System (ADS)

    Denny, Adam C.; Kozdon, Reinhard; Kitajima, Kouki; Valley, John W.

    2017-11-01

    SEM/SIMS imaging and analysis of δ18O and δ13C in sandstones from a transect through the Illinois Basin (USA) show systematic μm-scale isotopic zonation of up to 10‰ in both carbonate and quartz cements of the middle-Ordovician St. Peter and Cambrian Mt. Simon formations. Quartz δ18O values are broadly consistent with the model of Hyodo et al. (2014), wherein burial and heating in the Illinois Basin is recorded in systematically zoned quartz overgrowths. Observations of zoned dolomite/ankerite cements indicate that they preserve a more extended record of temperature and fluid compositions than quartz, including early diagenesis before or during shallow burial, and late carbonates formed after quartz overgrowths. Many carbonate cements show innermost dolomite with δ18O values (21-25‰ VSMOW) that are too low to have formed by deposition at low temperatures from ancient seawater (δ18O > - 3‰) and most likely reflect mixing with meteoric water. A sharp increase in Fe content is commonly observed in zoned carbonate cements to be associated with a drop in δ18O and an abrupt shift in δ13C to higher or lower values. These changes are interpreted to record the passage of hot metal-rich brines through sandstone aquifers, that was associated with Mississippi-Valley Type (MVT) Pb-Zn deposits (ca. 270 Ma) of the Upper Mississippi Valley. Local variability and individual trends in δ13C are likely controlled by the sources of carbon and the degree to which carbon is sourced from adjacent carbonate units or thermal maturation of organic matter. Quartz overgrowths in sandstones provide an excellent record of conditions during burial, heating, and pressure-solution, whereas carbonate cements in sandstones preserve a more-extended record including initial pre-burial conditions and punctuated fluid flow events.

  4. Seep carbonates and chemosynthetic coral communities in the Early Paleocene alpine accretionary wedge: evidences from the Bocco Shale (Internal Liguride ophiolitic sequence, Northern Apennine, Italy)

    NASA Astrophysics Data System (ADS)

    Pandolfi, Luca; Boschi, Chiara; Luvisi, Edoardo; Alessandro, Ellero; Marroni, Michele; Meneghini, Francesca

    2014-05-01

    In Northern Apennines, the Internal Liguride units are characterized by an ophiolite sequence that represents the stratigraphic base of a Late Jurassic-Early Paleocene sedimentary cover. The Bocco Shale represents the youngest deposit recognized in the sedimentary cover of the ophiolite sequence, sedimented just before the inception of subduction-related deformation history. The Bocco Shale has been interpreted as a fossil example of deposits related to the frontal tectonic erosion of the alpine accretionary wedge slope. The frontal tectonic erosion resulted in a large removal of material from the accretionary wedge front reworked as debris flows and slide deposits sedimented on the lower plate above the trench deposits. These trench-slope deposits may have been successively deformed and metamorphosed during the following accretion processes. The frontal tectonic erosion can be envisaged as a common process during the convergence-related evolution of the Ligure-Piemontese oceanic basin in the Late Cretaceous-Early Tertiary time span. In the uppermost Internal Liguride tectonic unit (Portello Unit of Pandolfi and Marroni. 1997), that crops-out in Trebbia Valley, several isolated blocks of authigenic carbonates, unidentificated corals and intrabasinal carbonatic arenites have been recognized inside the fine-grained sediments that dominate the Early Paleocene Lavagnola Fm. (cfr. Bocco Shale Auctt.). The preliminary data on stable isotopes from blocks of authigenic carbonates (up to 1 m thick and 3 m across) and associated corals archive a methane signatures in their depleted carbon isotope pattern (up to δ13C -30‰ PDB) and suggest the presence of chemosynthetic paleocommunities. The seep-carbonates recognized at the top of Internal Liguride succession (cfr. Bocco Shale Auctt.) occur predominantly as blocks in very thick mudstone-dominated deposits and probably developed in an environment dominated by the expulsion of large volume of cold methane-bearing fluids

  5. The oceanic carbon cycle implicated in the d13Ccarb and the d13Corg variations from the terminal Ediacaran to the Early Cambrian

    NASA Astrophysics Data System (ADS)

    Ishikawa, T.; Ueno, Y.; Komiya, T.; Shu, D.; Li, Y.; Yoshida, N.; Maruyama, S.

    2009-04-01

    The terminal Neoproterozoic and its transition into the Cambrian witnessed major evolutionary and geochemical changes (e.g. Knoll, 1994). Evolutionary features include extinction and subsequent radiation events (e.g. Brasier, 1994; Knoll, 1994; Knoll and Carroll, 1999; Shu 2008). Geochemical changes comprise secular variations of the global carbon cycle expressed as variations of the d13C isotope records. A representative d13C curve for inorganic carbon (d13Ccarb) across the Precambrian/Cambrian boundary (Pc/C boundary) shows the existence of large fluctuations (e.g. Kirschvink et al., 1991; Narbonne et al., 1994; Kaufman et al., 1995; Amthor et al., 2003; Maloof et al., 2005, Ishikawa et al., 2008). This indicates a significant change of the oceanic carbon cycle at that time. On the other hand, the d13C values for total organic carbon (d13Corg) have rarely been reported together with the d13Ccarb across the boundary. Therefore, the precise relation between the d13Ccarb and the d13Corg and the global carbon cycle at the Pc/C boundary are still ambiguous. This work presents a first high-resolution d13Corg chemostratigraphy of drill core samples across the Pc/C boundary in the Three Gorges area, South China. Based on the results, this work additionally proposes variations of the sizes of the oceanic carbon reservoirs by a calculation of the carbon cycle model at the Pc/C boundary. The Three Gorges section extends from the uppermost Ediacaran dolostone (Dengying Formation), through the lowermost Early Cambrian muddy limestone (Yanjiahe Formation) to the middle Early Cambrian calcareous black shale (Shuijingtuo Formation). The ^13Corg values exhibit relatively invariant values averaging at -31 permil. By comparison between the d13Ccarb and d13Corg, we recognize two different terms in this period. The first term from the Pc/C boundary to the early Nemakit-Daldynian (ND) is characterized by the decoupling of d13Corg and d13Ccarb, stable d13Corg and the significant

  6. Hydrochemical variations in selected geothermal groundwater and carbonated springs in Korea: a baseline study for early detection of CO2 leakage.

    PubMed

    Choi, Hanna; Piao, Jize; Woo, Nam C; Cho, Heuynam

    2017-02-01

    A baseline hydrochemistry of the above zone aquifer was examined for the potential of CO 2 early detection monitoring. Among the major ionic components and stable isotope ratios of oxygen, hydrogen, and carbon, components with a relative standard deviation (RSD) of <10 % for the seasonal variation were selected as relatively stable. These components were tested for sensitivity to the introduction of 0.1 mol/L CO 2 (g) using the PHREEQC simulation results. If the relatively stable components were sensitive to the introduction of CO 2 , then they could be used as indicators of CO 2 leakage into the above zone. As an analog to the zone above CO 2 storage formation, we sampled deep groundwater, including geothermal groundwater from well depths of 400-700 m below the ground surface (bgs) and carbonated springs with a high CO 2 content in Korea. Under the natural conditions of inland geothermal groundwater, pH, electrical conductivity (EC), bicarbonate (HCO 3 ), δ 18 O, δ 2 H, and δ 13 C were relatively stable as well as sensitive to the introduction of CO 2 (g), thus showing good potential as monitoring parameters for early detection of CO 2 leakage. In carbonated springs, the parameters identified were pH, δ 18 O, and δ 2 H. Baseline hydrochemistry monitoring could provide information on parameters useful for detecting anomalies caused by CO 2 leakage as measures for early warning.

  7. Trace elements and REE geochemistry of Middle Devonian carbonate mounds (Maïder Basin, Eastern Anti-Atlas, Morocco): Implications for early diagenetic processes

    NASA Astrophysics Data System (ADS)

    Franchi, Fulvio; Turetta, Clara; Cavalazzi, Barbara; Corami, Fabiana; Barbieri, Roberto

    2016-08-01

    Trace and rare earth elements (REEs) have proven their utility as tools for assessing the genesis and early diagenesis of widespread geological bodies such as carbonate mounds, whose genetic processes are not yet fully understood. Carbonates from the Middle Devonian conical mud mounds of the Maïder Basin (eastern Anti-Atlas, Morocco) have been analysed for their REE and trace element distribution. Collectively, the carbonates from the Maïder Basin mud mounds appear to display coherent REE patterns. Three different geochemical patterns, possibly related with three different diagenetic events, include: i) dyke fills with a normal marine REE pattern probably precipitated in equilibrium with seawater, ii) mound micrite with a particular enrichment of overall REE contents and variable Ce anomaly probably related to variation of pH, increase of alkalinity or dissolution/remineralization of organic matter during early diagenesis, and iii) haematite-rich vein fills precipitated from venting fluids of probable hydrothermal origin. Our results reinforce the hypothesis that these mounds were probably affected by an early diagenesis induced by microbial activity and triggered by abundance of dispersed organic matter, whilst venting may have affected the mounds during a later diagenetic phase.

  8. A Personalised Needs-Led Group Approach to Induction: Perceptions of Early Academics in a University School of Education

    ERIC Educational Resources Information Center

    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…

  9. Stakeholder perspectives on implementing a universal Lynch syndrome screening program: a qualitative study of early barriers and facilitators.

    PubMed

    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.

  10. Modeling Retention at a Large Public University: Can At-Risk Students Be Identified Early Enough to Treat?

    ERIC Educational Resources Information Center

    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…

  11. Degrees Awarded by Canadian Universities by Level and Discipline, During the Sixties and Early Seventies. Part I.

    ERIC Educational Resources Information Center

    von Zur-Muehlen, Max

    Data are provided on degrees awarded by Canadian universities by level (bachelor's and first professional, master's, and doctoral) and discipline (education, fine and applied arts, humanities and related, social science and related, agricultural and biological sciences, engineering and applied sciences, health professions and occupations, and…

  12. Big Five Personality Traits as Predictors of the Academic Success of University and College Students in Early Childhood Education

    ERIC Educational Resources Information Center

    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.…

  13. Fields of Plenty, Fields of Lean: The Early Labour Market Outcomes of Canadian University Graduates by Discipline.

    ERIC Educational Resources Information Center

    Finnie, Ross

    2001-01-01

    Analyzed early career outcomes of recent Canadian college graduates by discipline. Found that many outcomes conform to expectations: the professions and other applied disciplines generally experienced lower unemployment rates, closer skill and qualification matches, and higher earnings; however, fine arts and humanities graduates are more…

  14. Funding Early Years Education and Care: Can a Mixed Economy of Providers Deliver Universal High Quality Provision?

    ERIC Educational Resources Information Center

    West, Anne; Roberts, Jonathan; Noden, Philip

    2010-01-01

    There has been a focus on policies relating to early years education and care across the developed world and particularly in Europe. In the UK, there has been a raft of policy changes alongside increased investment. However, this paper argues that these changes may not be sufficient to meet EU objectives in terms of quality or the government's…

  15. The history of early low frequency radio astronomy in Australia. 9: the University of Tasmania's Llanherne (Hobart Airport) Field Station during the 1960s-1980s

    NASA Astrophysics Data System (ADS)

    George, Martin; Orchiston, Wayne; Wielebinski, Richard

    2018-04-01

    Beginning in the early 1960s, the University of Tasmania became very involved in low frequency radio astronomical studies, which was to continue into the 1980s. Although important low frequency arrays were set up at Penna and Richmond, the main location for this activity by the University was in the vicinity of Hobart Airport, known as Llanherne. This paper describes the work performed there at frequencies of 30 MHz and below, mainly for studying radio emission from Jupiter and the Galaxy. The largest of the installations was the Llanherne Low Frequency Array, a 640 × 640 m antenna array adjacent to Holyman Avenue; it was well known to the public because of its high visibility to airport patrons. Other installations were set up closer to the airport runway. Various researchers, including Graeme Ellis, Hilary Cane and others, made observations at Llanherne.

  16. Ability of admissions criteria to predict early academic performance among students of health science colleges at King Saud University, Saudi Arabia.

    PubMed

    Alhadlaq, Adel M; Alshammari, Osama F; Alsager, Saleh M; Neel, Khalid A Fouda; Mohamed, Ashry G

    2015-06-01

    The aim of this study was to evaluate the ability of admissions criteria at King Saud University (KSU), Riyadh, Saudi Arabia, to predict students' early academic performance at three health science colleges (medicine, dentistry, and pharmacy). A retrospective cohort study was conducted with data from the records of students enrolled in the three colleges from the 2008-09 to 2010-11 academic years. The admissions criteria-high school grade average (HSGA), aptitude test (APT) score, and achievement test (ACT) score-were the independent variables. The dependent variable was the average of students' first- and second-year grade point average (GPA). The results showed that the ACT was a better predictor of the students' early academic performance than the HSGA (β=0.368, β=0.254, respectively). No significant relationship was found between the APT and students' early academic performance (β=-0.019, p>0.01). The ACT was most predictive for pharmacy students (β=0.405), followed by dental students (β =0.392) and medical students (β=0.195). Overall, the current admissions criteria explained only 25.5% of the variance in the students' early academic performance. While the ACT and HSGA were found to be predictive of students' early academic performance in health colleges at KSU, the APT was not a strong predictor. Since the combined current admissions criteria for the health science colleges at KSU were weak predictors of the variance in early academic performance, it may be necessary to consider noncognitive evaluation methods during the admission process.

  17. [Central venous-arterial carbon dioxide tension to arterial-central venous oxygen content ratio combined with lactate clearance rate as early resuscitation goals of septic shock].

    PubMed

    Gao, X H; Li, P J; Cao, W

    2018-02-13

    Objective: To investigate the prognostic significance of central venous-arterial carbon dioxide tension to arterial-venous oxygen content ratio (Pcv-aCO(2)/Ca-cvO(2)) combined with lactate clearance rate (LCR) as early resuscitation goals of septic shock. Methods: One hundred and forty-five septic shock patients admitted to Second Department of Critical Care Medicine of Lanzhou University Second Hospital from March 2013 to May 2017 were enrolled in this study.All septic shock patients received an initial resuscitation therapy according to early goal-directed therapy.The arterial and central venous blood gases were measured simultaneously at baseline (T0) and 6 hours after resuscitation (T6). Pcv-aCO(2)/Ca-cvO(2) and LCR were calculated.Patients were classified into four groups according to Pcv-aCO(2)/Ca-cvO(2) and LCR at T6: group A, Pcv-aCO(2)/Ca-cvO(2)>1.8 and LCR<30%; group B, Pcv-aCO(2)/Ca-cvO(2)>1.8 and LCR≥30%; group C, Pcv-aCO(2)/Ca-cvO(2)≤1.8 and LCR<30%; group D, Pcv-aCO(2)/Ca-cvO(2)≤1.8 and LCR≥30%.General demographics, hemodynamic parameters, oxygen metabolism parameters, acute physiology and chronic health evaluation (APACHE Ⅱ) scores, sequential organ failure assessment (SOFA) scores, length of intensive care unit (ICU) stay, and 28-day mortality rate were compared among the 4 groups.A Kaplan-Meier curve showed the survival probabilities at day 28 using a log-rank test for multiple comparisons.Parameters were introduced into a Cox's proportional hazards regression model to analyze the prediction of 28-day mortality.Receiver operating characteristics (ROC) curves were constructed to evaluate the ability of Pcv-aCO(2)/Ca-cvO(2), LCR, Pcv-aCO(2)/Ca-cvO(2) combined with LCR at T6 to predict 28-day mortality. Results: Compared with patients in group A, patients from group D had the lower APACHE Ⅱ and SOFA score at day 3 ( t =-2.909, -3.630, both P <0.05), shorter ICU stay ( t =-2.575, P =0.011), and lower mortality rate at day 28 (χ(2)=3.124, P

  18. Development of the 2nd generation z(Redshift) and early universe spectrometer & the study of far-IR fine structure emission in high-z galaxies

    NASA Astrophysics Data System (ADS)

    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

  19. Near Infrared Observations of a Redshift 5.34 Galaxy: Further Evidence for Significant Dust Absorption in the Early Universe

    NASA Technical Reports Server (NTRS)

    Armus, L.; Matthews, K.; Neugebauer, G.; Soifer, B. T.

    1998-01-01

    In the last several years, the combination of new wavelength dropout discovery techniques coupled with the incredible power of deep imaging of the Hubble Space Telescope and the spectroscopic capabilities of a new generation of large ground-based telescopes, has lead to an astonishing blossoming of the study of galaxies at redshifts of z=2-4, when the Universe was less than 10-20% of its current age.

  20. Sedimentologic and paleoclimatic reconstructions of carbonate factory evolution in the Alborz Basin (northern Iran) indicate a global response to Early Carboniferous (Tournaisian) glaciations

    NASA Astrophysics Data System (ADS)

    Sardar Abadi, Mehrdad; Kulagina, Elena I.; Voeten, Dennis F. A. E.; Boulvain, Frédéric; Da Silva, Anne-Christine

    2017-03-01

    The Lower Carboniferous Mobarak Formation records the development of a storm-sensitive pervasive carbonate factory on the southern Paleo-Tethyan passive margin following the opening of the Paleo-Tethys Ocean into the Alborz Basin along the northern margin of Gondwana. Its depositional facies encompass inner ramp peritidal environments, peloidal to crinoidal shoals, storm to fair-weather influenced mid-ramps, proximal to distal shell beds and low energy outer ramps. Sedimentological analyses and foraminiferal biostratigraphy reveal four events affecting carbonate platform evolution in the Alborz Basin during the Lower Carboniferous: (1) A transgression following global temperature rise in the Early Tournaisian (middle Hastarian) caused the formation of thick-bedded argillaceous limestones. This interval correlates with Early Tournaisian nodular to argillaceous limestones in the Moravia Basin (Lisen Formation, Czech Republic), the Dinant Basin (Pont d'Arcole Formation, Belgium), and at the Rhenish Slate Mountains (Lower Alum shale, Germany). (2) Late Hastarian-early Ivorian glaciations previously identified in Southern Gondwana but had not yet recognized in Northern Gondwana were recorded through a sequence boundary. (3) During the Late Tournaisian-Early Visean?, a differential block faulting regime along the basin's margin caused uplift of the westernmost parts of the Alborz Basin and resulted in subsidence in the eastern part of the central basin. This tectonically controlled shift in depositional regime caused vast sub-aerial exposure and brecciation preserved in the top of the Mobarak Formation in the western portion of the Central Alborz Basin. (4) Tectonic activity coinciding with a progressive, multiphase sea level drop caused indirectly by the Viséan and Serpukhovian glaciations phases ultimately led to the stagnation of the carbonate factory. Paleothermometry proxies, the presence of foraminiferal taxa with a northern Paleo-Tethyan affinity and evidence for

  1. Carbon-carbon piston development

    NASA Technical Reports Server (NTRS)

    Gorton, Mark P.

    1994-01-01

    A new piston concept, made of carbon-carbon refractory-composite material, has been developed that overcomes a number of the shortcomings of aluminum pistons. Carbon-carbon material, developed in the early 1960's, is lighter in weight than aluminum, has higher strength and stiffness than aluminum and maintains these properties at temperatures over 2500 F. In addition, carbon-carbon material has a low coefficient of thermal expansion and excellent resistance to thermal shock. An effort, called the Advanced Carbon-Carbon Piston Program was started in 1986 to develop and test carbon-carbon pistons for use in spark ignition engines. The carbon-carbon pistons were designed to be replacements for existing aluminum pistons, using standard piston pin assemblies and using standard rings. Carbon-carbon pistons can potentially enable engines to be more reliable, more efficient and have greater power output. By utilizing the unique characteristics of carbon-carbon material a piston can: (1) have greater resistance to structural damage caused by overheating, lean air-fuel mixture conditions and detonation; (2) be designed to be lighter than an aluminum piston thus, reducing the reciprocating mass of an engine, and (3) be operated in a higher combustion temperature environment without failure.

  2. Early post-mortem formation of carbonate concretions around tusk-shells over week-month timescales

    NASA Astrophysics Data System (ADS)

    Yoshida, Hidekazu; Ujihara, Atsushi; Minami, Masayo; Asahara, Yoshihiro; Katsuta, Nagayoshi; Yamamoto, Koshi; Sirono, Sin-Iti; Maruyama, Ippei; Nishimoto, Shoji; Metcalfe, Richard

    2015-09-01

    Carbonate concretions occur in sedimentary rocks of widely varying geological ages throughout the world. Many of these concretions are isolated spheres, centered on fossils. The formation of such concretions has been variously explained by diffusion of inorganic carbon and organic matter in buried marine sediments. However, details of the syn-depositional chemical processes by which the isolated spherical shape developed and the associated carbon sources are little known. Here we present evidence that spherical carbonate concretions (diameters φ : 14 ~ 37 mm) around tusk-shells (Fissidentalium spp.) were formed within weeks or months following death of the organism by the seepage of fatty acid from decaying soft body tissues. Characteristic concentrations of carbonate around the mouth of a tusk-shell reveal very rapid formation during the decay of organic matter from the tusk-shell. Available observations and geochemical evidence have enabled us to construct a ‘Diffusion-growth rate cross-plot’ that can be used to estimate the growth rate of all kinds of isolated spherical carbonate concretions identified in marine formations. Results shown here suggest that isolated spherical concretions that are not associated with fossils might also be formed from carbon sourced in the decaying soft body tissues of non-skeletal organisms with otherwise low preservation potential.

  3. "Big Bang" as a result result of the curvature-driven first-order phase transition in the early cold Universe

    NASA Astrophysics Data System (ADS)

    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".

  4. Toward a universal carbonate clumped isotope calibration: Diverse synthesis and preparatory methods suggest a single temperature relationship

    NASA Astrophysics Data System (ADS)

    Kelson, Julia R.; Huntington, Katharine W.; Schauer, Andrew J.; Saenger, Casey; Lechler, Alex R.

    2017-01-01

    Carbonate clumped isotope (Δ47) thermometry has been applied to a wide range of problems in earth, ocean and biological sciences over the last decade, but is still plagued by discrepancies among empirical calibrations that show a range of Δ47-temperature sensitivities. The most commonly suggested causes of these discrepancies are the method of mineral precipitation and analytical differences, including the temperature of phosphoric acid used to digest carbonates. However, these mechanisms have yet to be tested in a consistent analytical setting, which makes it difficult to isolate the cause(s) of discrepancies and to evaluate which synthetic calibration is most appropriate for natural samples. Here, we systematically explore the impact of synthetic carbonate precipitation by replicating precipitation experiments of previous workers under a constant analytical setting. We (1) precipitate 56 synthetic carbonates at temperatures of 4-85 °C using different procedures to degas CO2, with and without the use of the enzyme carbonic anhydrase (CA) to promote rapid dissolved inorganic carbon (DIC) equilibration; (2) digest samples in phosphoric acid at both 90 °C and 25 °C; and (3) hold constant all analytical methods including acid preparation, CO2 purification, and mass spectrometry; and (4) reduce our data with 17O corrections that are appropriate for our samples. We find that the CO2 degassing method does not influence Δ47 values of these synthetic carbonates, and therefore probably only influences natural samples with very rapid degassing rates, like speleothems that precipitate out of drip solution with high pCO2. CA in solution does not influence Δ47 values in this work, suggesting that disequilibrium in the DIC pool is negligible. We also find the Δ47 values of samples reacted in 25 and 90 °C acid are within error of each other (once corrected with a constant acid fractionation factor). Taken together, our results show that the Δ47-temperature relationship

  5. Evolution of the carbon cycle and seawater temperature from the Triassic-Jurassic boundary to the Early Toarcian based on brachiopod geochemistry

    NASA Astrophysics Data System (ADS)

    Müller, Tamás; Tomašových, Adam

    2017-04-01

    The ecological crisis and extinction at the end of the Triassic coincides with several environmental perturbations such as global temperature rise, ocean acidification and carbon isotope anomalies, with a large observed negative carbon isotope excursion (CIE) in the Late Rhaetian as well. Followed by the ETE, the Early Jurassic was characterized by marked fluctuations of the global seawater temperature and carbon cycle. Carbon isotope records are showing positive and remarkable negative excursions. A particular example of these phenomena is connected to the Toarcian Oceanic Anoxic Event (TOAE). The δ13C record of the TOAE is showing a negative excursion of a high magnitude, suggesting the injection of large amount of light carbon into the ocean-atmosphere system, coinciding with rapid global warming and widespread anoxia. Beside the TOAE there are many other, smaller scale carbon isotope anomalies and environmental perturbations at the Sinemurian-Pliensbachian transition or at the Pliensbachian-Toarcian boundary. In our study, we provide new brachiopod δ13C, δ18O, and Mg/Ca data from the time interval starting in the Rhaetian till the end of the Early Toarcian. Considering the strong resistance of brachiopod shells against diagenesis, our aim is to reconstruct seawater temperature, seawater Mg/Ca, and carbon cycle evolution based on a reliable geochemical proxy database of the studied time interval. The samples have been collected from various localities across Europe achieving a good, at least ammonite subzone scale resolution for the Rhaetian stage and for the Lower Jurassic. The geochemical preservation of the shell material have been tested by several approaches. Thin-sections were made from the shells and analyzed by electron microprobe and ICP-OES to evaluate their preservation by assessing concentrations of Fe, Mn, Sr, and their ratios (Mn/Ca, Sr/Ca). Considering the various elemental composition data of fossil and recent brachiopods published by several

  6. High resolution stable isotope and carbonate variability during the early Oligocene climate transition: Walvis Ridge (ODP Site 1263)

    USGS Publications Warehouse

    2007-01-01

    resolution reconstruction of the Eocene/Oligocene from the Atlantic basin to date, and provide us with a unique opportunity to investigate the fine-scale interplay of glaciation and the global carbon cycle.

  7. An Inexpensive, Single Use Carbon-Based Sensor for the Rapid and Early Detection of Hydrocarbon Leaks.

    PubMed

    Sebastian, H Bri; Mayall, Robert M; Pilonieta, Roberto J; Bryant, Steven L

    2017-06-23

    A novel fabrication process for a single use, low-cost organic solvent sensor has been developed. The process is simple, and the materials are readily available. Carbon nanomaterials are self-assembled at a water/hexane interface, where the hexane phase contains dissolved paraffin wax. Upon the controlled evaporation of hexane, the paraffin wax precipitates, trapping the carbon nanoparticles at the surface in a paraffin wax backbone, realizing a carbon-nanoparticle-decorated film. The film is hydrophobic and highly electrically conductive. When exposed to hydrocarbons or a mixture of hydrocarbons, the conductive carbon network deteriorates and an increase in film resistivity is monitored. The rate of change in resistivity is proportional to the concentration and composition of organic molecules in contact with the film.

  8. Carbonate Microfabrics Symposium and Workshop Held Texas A&M University, College Station, Texas on 30 September-3 October 1990

    DTIC Science & Technology

    1990-10-03

    Center, Mississippi; and ARCO Oil and Gas Company, Piano, Texas. We are grateful to the following people for ideas and support during the planning...dissolution. In 1983, disturbed by the obviously severe effects of pressure-dissolution on the structures of oil fields , the oil companies active in...extreme depletion of the C-13 isotope (to values of 53.9 %co PDB) which associates them with carbon from oil and gas (both biogenic and thermogenic

  9. The FLARE mission: deep and wide-field 1-5um imaging and spectroscopy for the early universe: a proposal for M5 cosmic vision call

    NASA Astrophysics Data System (ADS)

    Burgarella, D.; Levacher, P.; Vives, S.; Dohlen, K.; Pascal, S.

    2016-07-01

    FLARE (First Light And Reionization Explorer) is a space mission that will be submitted to ESA (M5 call). Its primary goal (~80% of lifetime) is to identify and study the universe before the end of the reionization at z > 6. A secondary objective (~20% of lifetime) is to survey star formation in the Milky Way. FLARE's strategy optimizes the science return: imaging and spectroscopic integral-field observations will be carried out simultaneously on two parallel focal planes and over very wide instantaneous fields of view. FLARE will help addressing two of ESA's Cosmic Vision themes: a) << How did the universe originate and what is it made of? » and b) « What are the conditions for planet formation and the emergence of life? >> and more specifically, << From gas and dust to stars and planets >>. FLARE will provide to the ESA community a leading position to statistically study the early universe after JWST's deep but pin-hole surveys. Moreover, the instrumental development of wide-field imaging and wide-field integral-field spectroscopy in space will be a major breakthrough after making them available on ground-based telescopes.

  10. Modeling the Relationship between Transportation-Related Carbon Dioxide Emissions and Hybrid-Online Courses at a Large Urban University

    ERIC Educational Resources Information Center

    Little, Matthew; Cordero, Eugene

    2014-01-01

    Purpose: This paper aims to investigate the relationship between hybrid classes (where a per cent of the class meetings are online) and transportation-related CO[subscript 2] emissions at a commuter campus similar to San José State University (SJSU). Design/methodology/approach: A computer model was developed to calculate the number of trips to…

  11. Early-Stage Investigators and Institutional Interface: Importance of Organization in the Mentoring Culture of Today’s Universities

    PubMed Central

    Manson, Spero M.

    2016-01-01

    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. PMID:27044483

  12. Early-Stage Investigators and Institutional Interface: Importance of Organization in the Mentoring Culture of Today's Universities.

    PubMed

    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.

  13. Assessment of an intervention aimed at early discontinuation of intravenous antimicrobial therapy in a Brazilian University hospital.

    PubMed

    Bonella, Gislaine Ferraresi; Fontes, Astrídia Marília de Souza; Jorge, Miguel Tanús; Silveira, Alexandre Barcelos Morais da

    2016-01-01

    Many interventions demonstrate success in adapting the duration of intravenous antibiotic therapy, but few studies have been conducted in developing countries. The aim of this study was to evaluate the effectiveness of an intervention in the induction of early discontinuation of intravenous antimicrobial therapy and/or its switch to oral therapy. The study employed a before-after intervention design that consisted of displaying a message in the computerized prescription on the third day and suspension of the prescription on the fifth day of intravenous antimicrobial therapy. A total of 465 patients were followed during the control period (CP) and 440 in the intervention period (IP). The intravenous therapy was switched to oral therapy for 11 (2.4%) patients during the CP and 25 (5.7%) in the IP (p=0.011), and was discontinued for 82 (17.6%) patients during the CP and 106 (24.1%) in the IP (p=0.017). During the IP there was a significant increase of patients who had their antimicrobial treatment discontinued before the seventh day of intravenous treatment, 37.40% (49/131) in the IP and 16.13% (15/93) in the CP (p=0.0005). The duration of intravenous antimicrobial therapy decreased by one day, but it was not significant (p=0.136). It is concluded that the proposed intervention is effective in promoting the early discontinuation of antimicrobial treatment and/or switch to oral therapy. As long as a computerized system for prescription already exists, it is easy and inexpensive to be implemented, especially in hospitals in developing countries. Copyright © 2016 Sociedade Brasileira de Infectologia. Published by Elsevier Editora Ltda. All rights reserved.

  14. Collaborative, Early-undergraduate-focused REU Programs at Savannah State University have been Vital to Growing a Demographically Diverse Ocean Science Community

    NASA Astrophysics Data System (ADS)

    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

  15. Behavior of carbonate and magnesium ions in the initial crystallites at the early developmental stages of the rat calvaria.

    PubMed

    Kakei, M; Nakahara, H; Tamura, N; Itoh, H; Kumegawa, M

    1997-08-01

    Analysis of the contents of calcium (Ca), magnesium (Mg), phosphate, and carbonate ions in the mineral phase of rat calvaria specimens obtained at different developmental stages indicated that the mineral at the newborn stage contained a negligible amount of carbonate, but a high content of Mg. There was no significant difference in Ca and phosphate (as PO4) contents between the newborn material and that from later stages. A relatively large amount of carbonate was detected in the calvaria from 6-day-old rats, in which only immature crystals were observed, thus indicating the beginning of apatite formation. Furthermore, using laser Raman microprobe analysis we confirmed that the Raman peak at 1120 cm-1 band, indicative of a Mg-CO3 compound, appeared at the 6-day stage. We also observed that the Raman peak at 988 cm-1 found in the samples from the newborn seemed to have shifted to 963-962 cm-1 in the case of those obtained from 6-day-old rats, a shift which suggests the conversion from the non-apatitic to the apatitic form. These results indicate that carbonate ions might facilitate the initiation of crystal development by converting the inhibitory Mg ion into its inactive form (Mg-carbonate compound).

  16. Cobalt encapsulated N-doped defect-rich carbon nanotube as pH universal hydrogen evolution electrocatalyst

    NASA Astrophysics Data System (ADS)

    Zhang, Suyun; Xiao, Xinxin; Lv, Taotao; Lv, Xiaomeng; Liu, Botao; Wei, Wei; Liu, Jun

    2018-07-01

    Exploring efficient and economical Pt-free electrocatalysts is of great significance for the electrocatalytic hydrogen evolution reaction (HER). However, the rational design on an industrial scale is a formidable challenge. Herein, we reported a facile calcination at controlled temperatures to fabricate rationally assembled cobalt nanoparticles embedded in defect-rich N-doped carbon nanotubes (Co-NCNTs), which was derived from low-cost dicyanadiamide thermally polymerized with cobalt precursor forming metal-organic frameworks, then further calculation leading to final products. The as-obtained samples were endowed with high content of N as electrocatalytic active site, defect-rich structure and excellent synergistic effect between cobalt nanoparticles and carbon nanotubes toward electrocatalytic HER. As expected, Co-NCNTs were highly active and long-term stable with onset potentials of c.a. 15 mV in acidic electrolytes (0.5 M H2SO4), 70 mV in alkaline (1 M KOH) and 300 mV in neutral media (pH 7). Specially, to achieve the current density of 10 mA cm-2, the overpotential of 103 mV in acid, 204 mV in alkaline and 337 mV in neutral media was obtained. The enhanced HER performance was discussed in detail by adjusting the molar ratio of precursor and metal species. Moreover, the present synthetic route is easy to scale up and expand to other non-noble metal and alloy.

  17. Early thawing after snow removal and no straw mulching accelerates organic carbon cycling in a paddy soil in Northeast China.

    PubMed

    Zhang, Hao; Tang, Jie; Liang, Shuang; Li, Zhaoyang; Wang, Jingjing; Wang, Sining

    2018-03-01

    Variations in soil organic carbon (SOC) have implications for atmospheric CO 2 concentrations and the greenhouse effect. However, the effects of snow cover and straw mulching on the variations in SOC fractions across winter remain largely unknown. In this study, soil samples were collected during different stages of winter from an in situ experiment comprising three treatments: 1) snow removal with no straw mulching (Sn-SM-); 2) snow cover with no straw mulching (SC), and; 3) snow cover with straw mulching (SC + SM+). Results showed that labile organic carbon, semi-labile organic carbon, recalcitrant organic carbon (ROC), the light fraction of organic carbon (LFOC), and easily oxidized organic carbon (EOC) contents did not vary significantly (P > .05) during the unfrozen to hard frost stages. Compared to the unfrozen stage, microbial biomass carbon (MBC) contents decreased by 519.03 mg kg -1 , 325.21 mg kg -1 , and 244.09 mg kg -1 and dissolved organic carbon (DOC) contents increased by 473.36 mg kg -1 , 348.10 mg kg -1 , and 258.89 mg kg -1  at the hard frost stage in Sn-SM-, SC, and SC + SM + treatments, respectively. Throughout all thawing stages, > 61% and 59% of SOC and ROC accumulation, respectively in the three treatments were observed in thawing stage II, indicating that higher temperatures and microbial activities in thawing stage II accelerated the inputs of SOC and ROC. ROC accumulation accounted for >65% of the SOC accumulation and the proportions of ROC in SOC increased in the three treatments during the thawing stages. SC + SM + treatment maintained lower EOC contents during thawing stages than other treatments. The observation of lowest SOC and LFOC accumulation and contents in the SC + SM + treatment during thawing stages showed that SC + SM + experienced the least inputs of SOC in the soil. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Deglacial climate, carbon cycle and ocean chemistry changes in response to a terrestrial carbon release

    NASA Astrophysics Data System (ADS)

    Simmons, C. T.; Matthews, H. D.; Mysak, L. A.

    2016-02-01

    Researchers have proposed that a significant portion of the post-glacial rise in atmospheric CO2 could be due to the respiration of permafrost carbon stocks that formed over the course of glaciation. In this paper, we used the University of Victoria Earth System Climate Model v. 2.9 to simulate the deglacial and interglacial carbon cycle from the last glacial maximum to the present. The model's sensitivity to mid and high latitude terrestrial carbon storage is evaluated by including a 600 Pg C carbon pool parameterized to respire in concert with decreases in ice sheet surface area. The respiration of this stored carbon during the early stages of deglaciation had a large effect on the carbon cycle in these simulations, allowing atmospheric CO2 to increase by 40 ppmv in the model, with an additional 20 ppmv increase occurring in the case of a more realistic, prescribed CO2 radiative warming. These increases occurred prior to large-scale carbon uptake due to the reestablishment of boreal forests and peatlands in the proxy record (beginning in the early Holocene). Surprisingly, the large external carbon input to the atmosphere and oceans did not increase sediment dissolution and mean ocean alkalinity relative to a control simulation without the high latitude carbon reservoir. In addition, our simulations suggest that an early deglacial terrestrial carbon release may come closer to explaining some observed deglacial changes in deep-ocean carbonate concentrations than simulations without such a release. We conclude that the respiration of glacial soil carbon stores may have been an important contributor to the deglacial CO2 rise, particularly in the early stages of deglaciation.

  19. Type Ia Supernova Rate Measurements to Redshift 2.5 from CANDELS: Searching for Prompt Explosions in the Early Universe

    NASA Astrophysics Data System (ADS)

    Rodney, Steven A.; Riess, Adam G.; Strolger, Louis-Gregory; Dahlen, Tomas; Graur, Or; Casertano, Stefano; Dickinson, Mark E.; Ferguson, Henry C.; Garnavich, Peter; Hayden, Brian; Jha, Saurabh W.; Jones, David O.; Kirshner, Robert P.; Koekemoer, Anton M.; McCully, Curtis; Mobasher, Bahram; Patel, Brandon; Weiner, Benjamin J.; Cenko, S. Bradley; Clubb, Kelsey I.; Cooper, Michael; Filippenko, Alexei V.; Frederiksen, Teddy F.; Hjorth, Jens; Leibundgut, Bruno; Matheson, Thomas; Nayyeri, Hooshang; Penner, Kyle; Trump, Jonathan; Silverman, Jeffrey M.; U, Vivian; Azalee Bostroem, K.; Challis, Peter; Rajan, Abhijith; Wolff, Schuyler; Faber, S. M.; Grogin, Norman A.; Kocevski, Dale

    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 deg2 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_{P}\\,{=}\\,0.53^{\\ \\,\\, +/- 0.09}_{stat0.10} {}^{\\ \\, +/- 0.10}_{sys 0.26}, consistent with a delay time distribution that follows a simple t -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.

  20. Fructose 1-6 bisphosphate versus University of Wisconsin solution for rat liver preservation: does FBP prevent early mitochondrial injury?

    PubMed

    de Fraga, R S; Heinen, P E T; Kruel, C R P; Molin, S D; Mota, S M; Cerski, C T S; Gasperin, G; Souto, A A; de Oliveira, J R; Alvares-da-Silva, M R

    2011-06-01

    Fructose 1,6-biphosphate (FBP) has been shown to exert therapeutic effects in models of ischemia-reperfusion in organs other than the liver. This study compared FBP and University of Wisconsin (UW) solution during cold storage and reperfusion, among mitochondria of adult male Wistar rat livers. Adult male Wistar rats were assigned to two groups according to the preservation solution used; UW or FBP Aspartate transaminase (AST), alanine transferase (ALT); and lactic dehydrogenase (LDH) were measured in samples of the storage solution obtained at 2, 4 and 6 hours of preservation. After 6 hours of cold storage, we reperfused the liver, taking blood samples to measure AST, ALT, LDH, and throbarbituric acid reactive substances (TBARS). Hepatic fragments were processed for histologic analysis; for determinations of TBARS, catalase, and nitric oxide as well as for mitochondrial evaluation by infrared spectroscopy. During cold preservation, levels of AST and LDH in the storage solution were lower among the FBP group, but after reperfusion, serum levels of AST, ALT, and LDH were higher in this group, as was catalase activity. TBARS and nitric oxide were comparable between the groups. In the UW group there was a higher amide I/amide II ratio than in the FBP group, suggesting an abnormal protein structure of the mitochondrial membrane. No signs of preservation injury were observed in any liver biopsy, but sinusoidal congestion was present in livers preserved with FBP. FBP showed a protective effect for preservation during cold storage seeming to protect the mitochondrial membrane although it did not prevent reperfusion injury. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. A small amount of mini-charged dark matter could cool the baryons in the early Universe.

    PubMed

    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.

  2. Type Ia Supernova Rate Measurements to Redshift 2.5 from Candles: Searching for Prompt Explosions in the Early Universe

    NASA Technical Reports Server (NTRS)

    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.

  3. Eccentricity and obliquity paced carbon cycling in the Early Triassic and implications for post-extinction ecosystem recovery

    PubMed Central

    Fu, Wanlu; Jiang, Da-yong; Montañez, Isabel P.; Meyers, Stephen R.; Motani, Ryosuke; Tintori, Andrea

    2016-01-01

    The timing of marine ecosystem recovery following the End Permian Mass Extinction (EPME) remains poorly constrained given the lack of radiometric ages. Here we develop a high-resolution carbonate carbon isotope (δ13Ccarb) record for 3.20 million years of the Olenekian in South China that defines the astronomical time-scale for the critical interval of major evolutionary and oceanic events in the Spathian. δ13Ccarb documents eccentricity modulation of carbon cycling through the period and a strong obliquity signal. A shift in phasing between short and long eccentricity modulation, and amplification of obliquity, is nearly coincident with a 2% decrease in seawater δ13CDIC, the last of a longer-term stepped decrease through t