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Sample records for studying nova nucleosynthesis

  1. Nucleosynthesis and the nova outburst

    International Nuclear Information System (INIS)

    Starrfield, S.

    1995-01-01

    A nova outburst is the consequence of the accretion of hydrogen rich material onto a white dwarf and it can be considered as the largest hydrogen bomb in the Universe. The fuel is supplied by a secondary star in a close binary system while the strong degeneracy of the massive white dwarf acts to contain the gas during the early stages of the explosion. The containment allows the temperature in the nuclear burning region to exceed 10 8 K under all circumstances. As a result a major fraction of CNO nuclei in the envelope are transformed into β + -unstable nuclei. We discuss the effects of these nuclei on the evolution. Recent observational studies have shown that there are two compositional classes of novae; one which occurs on carbon-oxygen white dwarfs, and a second class that occurs on oxygen-neon-magnesium white dwarfs. In this review we will concentrate on the latter explosions since they produce the most interesting nucleosynthesis. We report both on the results of new observational determinations of nova abundances and, in addition, new hydrodynamic calculations that examine the consequences of the accretion process on 1.0M circle-dot , 1.25M circle-dot , and 1.35M circle-dot white dwarfs. Our results show that novae can produce 22 Na, 26 Al, and other intermediate mass nuclei in interesting amounts. We will present the results of new calculations, done with updated nuclear reaction rates and opacities, which exhibit quantitative differences with respect to published work

  2. Nucleosynthesis in nova outbursts

    International Nuclear Information System (INIS)

    Iliadis, C.; Azuma, R.E.; Buchmann, L.

    1994-02-01

    Astronomical observations have shown that He, CNO material and/or heavy elements are considerably enriched in certain nova ejecta relative to solar matter. The heavy element enrichments can be explained by the dredge-up of matter from an underlying ONeMg white dwarf and subsequent redistribution of the material by the rp-process. The proton capture reactions on 32 S and 36 A r important for hydrogen burning during nova outbursts have been measured experimentally. The derived stellar reaction rates have been incorporated into large-scale network calculations and the astrophysical consequences are discussed. (author)

  3. Nucleosynthesis in nova outbursts

    Energy Technology Data Exchange (ETDEWEB)

    Iliadis, C [TRIUMF, Vancouver, BC (Canada); [Univ. of Toronto, McLennan Physical Labs., Toronto, ON (Canada); Azuma, R E [Univ. of Toronto, McLennan Physical Lab., Toronto, ON (Canada); Buchmann, L [TRIUMF, Vancouver, BC (Canada); and others

    1994-02-01

    Astronomical observations have shown that He, CNO material and/or heavy elements are considerably enriched in certain nova ejecta relative to solar matter. The heavy element enrichments can be explained by the dredge-up of matter from an underlying ONeMg white dwarf and subsequent redistribution of the material by the rp-process. The proton capture reactions on 32{sup S} and 36{sup A}r important for hydrogen burning during nova outbursts have been measured experimentally. The derived stellar reaction rates have been incorporated into large-scale network calculations and the astrophysical consequences are discussed. (author) 17 refs., 2 figs.

  4. Measurement of Reactions on 30P for Nova Nucleosynthesis

    Science.gov (United States)

    Ma, Z.; Guidry, M. W.; Hix, W. R.; Smith, M. S.

    2003-05-01

    Replace these paragraphs with your abstract. We encourage you to include a sentence acknowledging your funding agency. In a recent study the 30P(p,gamma)31S rate played a crucial role in the synthesis of heavier nuclear species, from Si to Ca, in nova outbursts on ONe White Dwarfs [1]. The adopted rate of this reaction, based on a Hauser-Feshbach calculation [2], has a large uncertainty and could be as much as a factor of 100 too high or too low [3]. In their study, Jose et al.[1] varied the 30P(p,gamma)31S reaction rate within this uncertainty and found that, when rate is reduced by a factor of 100, the synthesis of elements above Si is lowered by a factor 10 with respect to the values found with the nominal rate. This has important consequences for nova nucleosynthesis, as overproduction of isotopes in the Si to Ca mass region has been observed in the ejecta from some nova explosions (e.g.,[4,5]). While generally valid at higher temperatures, Hauser-Feshbach calculations of the rates at nova temperatures can have large uncertainties. At these temperatures, the rate is more likely dominated by a few individual nuclear resonances. At present there are about 10 31S resonances known above the 30P + p threshold that may contribute to the 30P(p,gamma)31S reaction rate at nova temperatures. The excitation energies of these levels are known but spins and parities (for all but two) are not. We plan to measure the 30P(p,p)30P and 30P(p,gamma)31S reactions at HRIBF to better determine this reaction rate. A detailed description of the experiments will be given. We are also conducting a new nova nucleosynthesis simulation over multiple spatial zones of the exploding envelope to investigate the influence of the 30P(p,gamma)31S reaction rate on nova nucleosynthesis. The results of these calculations will be discussed. 1. Jose , J., Coc, A., Hernanz, M., Astrophys. J., 560, 897(2001). 2. Thielemann, F.-K et al., 1987, Advances in Nuclear Astrophysics, ed. E. Vangioni-Flam ( Gif

  5. Nova Ophiuchus 2017 as a Probe of 13C Nucleosynthesis and Carbon Monoxide Formation and Destruction in Classical Novae

    Science.gov (United States)

    Joshi, Vishal; Banerjee, D. P. K.; Srivastava, Mudit

    2017-12-01

    We present a series of near-infrared spectra of Nova Ophiuchus 2017 in the K band that record the evolution of the first overtone CO emission in unprecedented detail. Starting from 11.7 days after maximum, when CO is first detected at great strength, the spectra track the CO emission to +25.6 days by which time it is found to have rapidly declined in strength by almost a factor of ∼35. The cause for the rapid destruction of CO is examined in the framework of different mechanisms for CO destruction, namely, an increase in photoionizating flux, chemical pathways of destruction, or destruction by energetic nonthermal particles created in shocks. From LTE modeling of the CO emission, the 12C/13C ratio is determined to be 1.6 ± 0.3. This is consistent with the expected value of this parameter from nucleosynthesis theory for a nova eruption occuring on a low mass (∼ 0.6 {M}ȯ ) carbon–oxygen core white dwarf. The present 12C/13C estimate constitutes one of the most secure estimates of this ratio in a classical nova.

  6. Bottlenecks and Waiting Points in Nucleosynthesis in X-ray bursts and Novae

    Science.gov (United States)

    Smith, Michael S.; Sunayama, Tomomi; Hix, W. Raphael; Lingerfelt, Eric J.; Nesaraja, Caroline D.

    2010-08-01

    To better understand the energy generation and element synthesis occurring in novae and X-ray bursts, we give quantitative definitions to the concepts of ``bottlenecks'' and ``waiting points'' in the thermonuclear reaction flow. We use these criteria to search for bottlenecks and waiting points in post-processing element synthesis explosion simulations. We have incorporated these into the Computational Infrastructure for Nuclear Astrophysics, a suite of nuclear astrophysics codes available online at nucastrodata.org, so that anyone may perform custom searches for bottlenecks and waiting points.

  7. Nova target chamber decontamination study

    International Nuclear Information System (INIS)

    1979-05-01

    An engineering study was performed to determine the most effective method for decontamination of the Nova target chamber. Manual and remote decontamination methods currently being used were surveyed. In addition, a concept that may not require in-situ decontamination was investigated. Based on the presently available information concerning material and system compatibility and particle penetration, it is recommended that a system of removable aluminum shields be considered. It is also recommended that a series of tests be performed to more precisely determine the vacuum compatibility and penetrability of other materials discussed in this report

  8. Explosive nucleosynthesis in zones rich in hydrogen and helium

    International Nuclear Information System (INIS)

    Toussaint, Jacques.

    1975-01-01

    Explosive nucleosynthesis was studied for element with masses lower than that of 35 Cl at temperatures between 10 8 to 10 9 K. It is shown that in some astrophysical objects (Novae, Supernovae or super-massive-stars) an explosive nucleosynthesis of isotopes such as 3 He, 7 Li, 25 Mg or 29 Si is possible. The existence of those elements in the interstellar medium would make possible, ultimately, the formation of heavier elements (iron peak and above) [fr

  9. Explosive Nucleosynthesis Study Using Laser Driven γ-ray Pulses

    Directory of Open Access Journals (Sweden)

    Takehito Hayakawa

    2017-03-01

    Full Text Available We propose nuclear experiments using γ-ray pulses provided from high field plasma generated by high peak power laser. These γ-ray pulses have the excellent features of extremely short pulse, high intensity, and continuous energy distribution. These features are suitable for the study of explosive nucleosyntheses in novae and supernovae, such as the γ process and ν process. We discuss how to generate suitable γ-ray pulses and the nuclear astrophysics involved.

  10. NOVA.

    Science.gov (United States)

    WGBH-TV, Boston, MA.

    News clippings, reviews, and feature articles about the Public Broadcasting System science-adventure series "Nova" are collected here. Included are comments from the New York Times, Washington Post, Christian Science Monitor, and TV Guide. Commentaries are primarily favorable and include synopses of various episodes. (DGC)

  11. Nova Scotia wind integration study : final report

    International Nuclear Information System (INIS)

    2008-01-01

    An independent study was commissioned by the Nova Scotia Department of Energy to identify and assess the impacts of integrating large scale wind power generation into Nova Scotia's electric power system. The purpose of the study was to help Nova Scotia's efforts towards building its renewable energy supply, in order to secure a local energy resource and to protect the environment. This report provided an overview of Nova Scotia's electric power sector, including organizations involved; existing generation system; existing transmission system; renewable energy standards; Nova Scotia Power integrated resource plan; and 2007 renewable energy request for proposals. The major assumptions for the study that were discussed included system parameters; system capacity reserve requirements; expansion plans to 2020; and allocation of new wind generation by zone. Wind resource data and system dispatch modeling were also presented and transmission system modeling was outlined. This included a discussion of steady state reliability requirements; inputs to the load flow model; load flow study and contingency analysis; intra-province transmission congestion; and potential impacts on system security. The report also presented an approach to impact analysis and mitigation such as the impact on greenhouse gas and other air emissions and the impact of wind energy prices on system costs. It was concluded that one of the most important factors in evaluation of the economic impact of wind power integration is the forecasted fuel prices for the thermal units. If the fuel prices had varied significantly from the forecasted values, the study economic impact results could have been quite different. 55 tabs., 64 figs., 1 appendix

  12. Primordial nucleosynthesis

    International Nuclear Information System (INIS)

    Gustavino, C.; Anders, M.; Bemmerer, D.; Elekes, Z.; Trezzi, D.

    2016-01-01

    Big Bang nucleosynthesis (BBN) describes the production of light nuclei in the early phases of the Universe. For this, precise knowledge of the cosmological parameters, such as the baryon density, as well as the cross section of the fusion reactions involved are needed. In general, the energies of interest for BBN are so low (E < 1 MeV) that nuclear cross section measurements are practically unfeasible at the Earth's surface. As of today, LUNA (Laboratory for Underground Nuclear Astrophysics) has been the only facility in the world available to perform direct measurements of small cross section in a very low background radiation. Owing to the background suppression provided by about 1400 meters of rock at the Laboratori Nazionali del Gran Sasso (LNGS), Italy, and to the high current offered by the LUNA accelerator, it has been possible to investigate cross sections at energies of interest for Big Bang nucleosynthesis using protons, 3 He and alpha particles as projectiles. The main reaction studied in the past at LUNA is the 2 H( 4 He, γ) 6 Li. Its cross section was measured directly, for the first time, in the BBN energy range. Other processes like 2 H(p, γ) 3 He, 3 He( 2 H, p) 4 He and 3 He( 4 He, γ) 7 Be were also studied at LUNA, thus enabling to reduce the uncertainty on the overall reaction rate and consequently on the determination of primordial abundances. The improvements on BBN due to the LUNA experimental data will be discussed and a perspective of future measurements will be outlined. (orig.)

  13. Sun's dynamics and nucleosynthesis

    International Nuclear Information System (INIS)

    Gavanescu, Adela; Rusu, Mircea V.

    2005-01-01

    Nucleosynthesis processes in the sun are one of the main results related to the evolution of the Sun. Dynamics and energetics of the Sun could be studied indirectly by their elements products in produced by nucleosynthesis. Also solar atmosphere and its characteristics reveled in its full development is observed during the solar eclipses. We try to correlate these facts in order to obtained data to be used in solar models. (authors)

  14. Study of the supernova nucleosynthesis 40Ca(α,γ)44Ti reaction: progress report

    International Nuclear Information System (INIS)

    Nassar, H.; Paul, M.; Ghelberg, S.; Ofan, A.; Trubnikov, N.; Ben-Dov, Y.; Hass, M.; Nara Singh, B.S.

    2005-01-01

    We report on a study of the α-capture reaction on 40 Ca in the energy range relevant to supernova nucleosynthesis (T 9 ∼ 0.8-3). The experiment measures the overall yield of 44 Ti nuclei produced in an activation of a thick 4 He target by a 40 Ca beam. Preliminary results show a significantly stronger yield than observed in previous measurements in the range T 9 ∼ 1.5-3

  15. Primordial Nucleosynthesis

    International Nuclear Information System (INIS)

    Coc, Alain

    2013-01-01

    Primordial nucleosynthesis, or Big Bang Nucleosynthesis (BBN), is one of the three evidences for the Big-Bang model, together with the expansion of the Universe and the Cosmic Microwave Background. There is a good global agreement over a range of nine orders of magnitude between abundances of 4 He, D, 3 He and 7 Li deduced from observations, and calculated in primordial nucleosynthesis. This comparison was used to determine the baryonic density of the Universe. For this purpose, it is now superseded by the analysis of the Cosmic Microwave Background (CMB) radiation anisotropies. However, there remain, a yet unexplained, discrepancy of a factor 3-5, between the calculated and observed lithium primordial abundances, that has not been reduced, neither by recent nuclear physics experiments, nor by new observations. We review here the nuclear physics aspects of BBN for the production of 4 He, D, 3 He and 7 Li, but also 6 Li, 9 Be, 11 B and up to CNO isotopes. These are, for instance, important for the initial composition of the matter at the origin of the first stars. Big-Bang nucleosynthesis, that has been used, to first constrain the baryonic density, and the number of neutrino families, remains, a valuable tool to probe the physics of the early Universe, like variation of ''constants'' or alternative theories of gravity.

  16. Experimental approach to explosive nucleosynthesis

    International Nuclear Information System (INIS)

    Kubono, S.

    1991-07-01

    Recent development of experimental studies on explosive nucleosynthesis, especially the rapid proton process and the primordial nucleosynthesis were discussed with a stress on unstable nuclei. New development in the experimental methods for the nuclear astrophysics is also discussed which use unstable nuclear beams. (author)

  17. Explosive processes in nucleosynthesis

    International Nuclear Information System (INIS)

    Boyd, R.N.

    2002-01-01

    There are many explosive processes in nucleosynthesis: big bang nucleosynthesis, the rp-process, the γ-process, the ν-process, and the r-process. However, I will discuss just the rp-process and the r-process in detail, primarily because both seem to have been very active research areas of late, and because they have great potential for studies with radioactive nuclear beams. I will also discuss briefly the γ-process because of its inevitability in conjunction with the rp-process. (orig.)

  18. Primordial Nucleosynthesis

    Science.gov (United States)

    Coc, Alain

    Primordial or big bang nucleosynthesis (BBN) is now a parameter free theory whose predictions are in good overall agreement with observations. However, the 7Li calculated abundance is significantly higher than the one deduced from spectroscopic observations. Most solutions to this lithium problem involve a source of extra neutrons that inevitably leads to an increase of the deuterium abundance. This seems now to be excluded by recent deuterium observations that have drastically reduced the uncertainty on D/H and also calls for improved precision on thermonuclear reaction rates.

  19. A multiwavelength study of superoutbursts in dwarf novae

    International Nuclear Information System (INIS)

    Woerd, H.J. van der.

    1987-01-01

    Dwarf novae are stellar systems consisting of two stars which orbit around each other within a few hours. In dwarf novae one of the stars, which is a bit smaller and less massive than our sun, loses matter to a very compact and degenerated star: a white dwarf. This white dwarf has nearly the same mass as our sun but its radius is about a hundred times smaller. The process of mass transport was studied on the basis of observations with the Exosat-satelite (European X-ray Observatory satelite). 397 refs.; 50 figs.; 21 tabs

  20. New studies of nuclear decay γ-rays from novae

    International Nuclear Information System (INIS)

    Starrfield, S.; Truran, J.W.; Wiescher, M.C.; Sparks, W.M.

    1997-01-01

    The cause of the nova outburst is a thermonuclear runaway (TNR) in hydrogen rich material transferred by a companion onto a white dwarf. Studies of this phenomenon have shown that the TNR produces large concentrations of the short lived positron unstable isotopes of the CNO nuclei which are transported to the surface by convection so that early in the outburst we expect significant numbers of radioactive decays to occur at the surface. The resulting γ-ray emission may be detectable from nearby novae early in their outbursts. The TNR is also expected to produce substantial amounts of 7 Be and 22 Na. Their decays also yield potentially detectable levels of γ-ray emission for relatively nearby novae. We are also interested in the role played by novae in the production of the ∼2M circle-dot of 26 Al found in the galaxy. In order to improve our predictions of this phenomenon, we have performed a new set of calculations of TNR close-quote s on ONeMg and CO white dwarfs with an updated nuclear reaction network and opacities. copyright 1997 American Institute of Physics

  1. Experimental study of the {sup 22}Ne(p,{gamma}){sup 23}Na reaction and its implications for novae scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, Marie-Luise

    2013-08-01

    The {sup 22}Ne(p,{gamma}){sup 23}Na reaction belongs to the catalytic neon-sodium cycle and has an important role in the explosive hydrogen burning. The neon-sodium cycle takes place at temperatures of T = 0.1 - 0.5 GK and is assumed to occur in different astrophysical systems: e.g. in novae, in super novae of type Ia and during the shell-burning of red giant branch stars. The implications of {sup 22}Ne(p,{gamma}){sup 23}Na and the neon-sodium cycle in a nova scenario have been studied by using the nuclear network code libnucnet at GSI in Darmstadt. A nova is an outburst of matter in a binary system consisting of a white dwarf and a red giant star. It is therefore a representative phenomenon for explosive hydrogen burning. For the calculation of the nucleosynthesis during the nova outburst, the code libnucnet requires the initial mass composition of the novae partners, the temperature and density profiles of the nova explosion and the thermonuclear reaction rates of the participating reactions. In the following, the code determined the flow and the final atomic abundance in the neon-sodium cycle during the entire nova process. Additionally, the influence of the temperature profile of the novae outburst as well as the thermonuclear reaction rate of the {sup 22}Ne(p,{gamma}){sup 23}Na reaction on the final atomic abundance in the outburst has been studied. A characteristic measure for the reactions in astrophysical environments is the thermonuclear reaction rate. The reaction rate of {sup 22}Ne(p,{gamma}){sup 23}Na has still strong uncertainties in the temperature range of T = 0.03 - 0.3 GK. These uncertainties are based on insufficient upper limits of the resonance strengths as well as the possible existence of tentative states that are populated in the energy range of E{sup lab}{sub p} = 30 - 300 keV. The research presented in this thesis is dedicated to the experimental study of the {sup 22}Ne(p,{gamma}){sup 23}Na reaction for an improved determination of the

  2. Experimental study of the 22Ne(p,γ)23Na reaction and its implications for novae scenarios

    International Nuclear Information System (INIS)

    Menzel, Marie-Luise

    2013-01-01

    The 22 Ne(p,γ) 23 Na reaction belongs to the catalytic neon-sodium cycle and has an important role in the explosive hydrogen burning. The neon-sodium cycle takes place at temperatures of T = 0.1 - 0.5 GK and is assumed to occur in different astrophysical systems: e.g. in novae, in super novae of type Ia and during the shell-burning of red giant branch stars. The implications of 22 Ne(p,γ) 23 Na and the neon-sodium cycle in a nova scenario have been studied by using the nuclear network code libnucnet at GSI in Darmstadt. A nova is an outburst of matter in a binary system consisting of a white dwarf and a red giant star. It is therefore a representative phenomenon for explosive hydrogen burning. For the calculation of the nucleosynthesis during the nova outburst, the code libnucnet requires the initial mass composition of the novae partners, the temperature and density profiles of the nova explosion and the thermonuclear reaction rates of the participating reactions. In the following, the code determined the flow and the final atomic abundance in the neon-sodium cycle during the entire nova process. Additionally, the influence of the temperature profile of the novae outburst as well as the thermonuclear reaction rate of the 22 Ne(p,γ) 23 Na reaction on the final atomic abundance in the outburst has been studied. A characteristic measure for the reactions in astrophysical environments is the thermonuclear reaction rate. The reaction rate of 22 Ne(p,γ) 23 Na has still strong uncertainties in the temperature range of T = 0.03 - 0.3 GK. These uncertainties are based on insufficient upper limits of the resonance strengths as well as the possible existence of tentative states that are populated in the energy range of E lab p = 30 - 300 keV. The research presented in this thesis is dedicated to the experimental study of the 22 Ne(p,γ) 23 Na reaction for an improved determination of the thermonuclear reaction rate. Furthermore, the implications of 22 Ne(p,γ) 23 Na and

  3. Primordial nucleosynthesis.

    Science.gov (United States)

    Schramm, D N

    1998-01-06

    With the advent of the new extragalactic deuterium observations, Big Bang nucleosynthesis (BBN) is on the verge of undergoing a transformation. In the past, the emphasis has been on demonstrating the concordance of the BBN model with the abundances of the light isotopes extrapolated back to their primordial values by using stellar and galactic evolution theories. As a direct measure of primordial deuterium is converged upon, the nature of the field will shift to using the much more precise primordial D/H to constrain the more flexible stellar and galactic evolution models (although the question of potential systematic error in 4He abundance determinations remains open). The remarkable success of the theory to date in establishing the concordance has led to the very robust conclusion of BBN regarding the baryon density. This robustness remains even through major model variations such as an assumed first-order quark-hadron phase transition. The BBN constraints on the cosmological baryon density are reviewed and demonstrate that the bulk of the baryons are dark and also that the bulk of the matter in the universe is nonbaryonic. Comparison of baryonic density arguments from Lyman-alpha clouds, x-ray gas in clusters, and the microwave anisotropy are made.

  4. Study on the dominant reaction path in nucleosynthesis during stellar evolution by means of the Monte Carlo method

    International Nuclear Information System (INIS)

    Yamamoto, K.; Hashizume, K.; Wada, T.; Ohta, M.; Suda, T.; Nishimura, T.; Fujimoto, M. Y.; Kato, K.; Aikawa, M.

    2006-01-01

    We propose a Monte Carlo method to study the reaction paths in nucleosynthesis during stellar evolution. Determination of reaction paths is important to obtain the physical picture of stellar evolution. The combination of network calculation and our method gives us a better understanding of physical picture. We apply our method to the case of the helium shell flash model in the extremely metal poor star

  5. The primordial nucleosynthesis

    International Nuclear Information System (INIS)

    Audouze, J.

    1984-01-01

    This review of the primordial nucleosynthesis is divided in three chapters. In the first the author attempts to determine the primordial abundances of the lightest elements which can be formed by the Big Bang nucleosynthesis. The second is a summary of the Standard Big Bang nucleosynthesis. This simple and attractive model might be found in difficulty in the case of a primordial abundance of He <= 0.24 and/or in the case of models of galactic evolution allowing infall of external matter having a primordial composition. Finally, in the third, two alternative proposals to the Standard Big Bang nucleosynthesis are summarized. (Auth.)

  6. Introduction to nucleosynthesis

    International Nuclear Information System (INIS)

    Guasp, J.

    1975-01-01

    After a short introduction on stellar evolution, the physical foundations of nucleosynthesis are exposed: H, He, C and O fusion, Si burning and the equilibrium process. The effect of neutrinos in the last stages of stellar evolution and Supernova explosions are treated too. Afterwards the neutron capture process, fast and slow, are considerated concluding with cosmic nucleogenesis and nucleosynthesis in overmasive objects. (author)

  7. Primordial nucleosynthesis: Beyond the standard model

    International Nuclear Information System (INIS)

    Malaney, R.A.

    1991-01-01

    Non-standard primordial nucleosynthesis merits continued study for several reasons. First and foremost are the important implications determined from primordial nucleosynthesis regarding the composition of the matter in the universe. Second, the production and the subsequent observation of the primordial isotopes is the most direct experimental link with the early (t approx-lt 1 sec) universe. Third, studies of primordial nucleosynthesis allow for important, and otherwise unattainable, constraints on many aspects of particle physics. Finally, there is tentative evidence which suggests that the Standard Big Bang (SBB) model is incorrect in that it cannot reproduce the inferred primordial abundances for a single value of the baryon-to-photon ratio. Reviewed here are some aspects of non-standard primordial nucleosynthesis which mostly overlap with the authors own personal interest. He begins with a short discussion of the SBB nucleosynthesis theory, high-lighting some recent related developments. Next he discusses how recent observations of helium and lithium abundances may indicate looming problems for the SBB model. He then discusses how the QCD phase transition, neutrinos, and cosmic strings can influence primordial nucleosynthesis. He concludes with a short discussion of the multitude of other non-standard nucleosynthesis models found in the literature, and make some comments on possible progress in the future. 58 refs., 7 figs., 2 tabs

  8. A deep optical imaging study of the nebular remnants of classical novae

    Science.gov (United States)

    Slavin, A. J.; O'Brien, T. J.; Dunlop, J. S.

    1995-09-01

    An optical imaging study of old nova remnants has revealed previously unobserved features in the shells of 13 classical novae - DQ Her, FH Ser, HR Del, GK Per, V1500 Cyg, T Aur, V533 Her, NQ Vul, V476 Cyg, DK Lac, LV Vul, RW UMi and V450 Cyg. These data indicate a possible correlation between nova speed class and the ellipticity of the resulting remnants - those of faster novae tend to comprise randomly distributed clumps of ejecta superposed on spherically symmetric diffuse material, whilst slower novae produce more structured ellipsoidal remnants with at least one and sometimes several rings of enhanced emission. By measuring the extent of the resolved shells and combining this information with previously published ejection speeds, we use expansion parallax to estimate distances for the 13 novae. Whilst we are able to deduce new information about every nova, it is notable that these observations include the first detections of shells around the old novae V450 Cyg and NQ Vul, and that velocity-resolved images of FH Ser and DQ Her have enabled us to estimate their orbital inclinations. Our observations of DQ Her also show that the main ellipsoidal shell is constricted by three rings and surrounded by a faint halo; this halo contains long tails extending outwards from bright knots, perhaps indicating that during or after outburst a fast inner wind has broken through the fractured principal shell.

  9. Nucleosynthesis outreach slides

    Energy Technology Data Exchange (ETDEWEB)

    Lippuner, Jonas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-03

    The purpose of this report is to explain s- and r-process nucleosynthesis to the general public at outreach events, specifically in a Planetarium show at the Pajarito Environmental Education Center in Los Alamos.

  10. A Trojan Horse Approach to the Production of {sup 18}F in Novae

    Energy Technology Data Exchange (ETDEWEB)

    Cognata, M. La; Pizzone, R. G.; Cherubini, S.; Gulino, M.; Rapisarda, G. G.; Spitaleri, C. [INFN—Laboratori Nazionali del Sud, Catania (Italy); José, J. [Departament de Física, EEBE, Universitat Politècnica de Catalunya, E-08019 Barcelona (Spain); Hernanz, M., E-mail: lacognata@lns.infn.it [Institut d’Estudis Espacials de Catalunya, E-08034 Barcelona (Spain)

    2017-09-01

    Crucial information on nova nucleosynthesis can be potentially inferred from γ -ray signals powered by {sup 18}F decay. Therefore, the reaction network producing and destroying this radioactive isotope has been extensively studied in the last years. Among those reactions, the {sup 18}F(p, α ){sup 15}O cross-section has been measured by means of several dedicated experiments, both using direct and indirect methods. The presence of interfering resonances in the energy region of astrophysical interest has been reported by many authors including the recent applications of the Trojan Horse Method. In this work, we evaluate what changes are introduced by the Trojan Horse data in the {sup 18}F(p, α ){sup 15}O astrophysical factor recommended in a recent R-matrix analysis, accounting for existing direct and indirect measurements. Then the updated reaction rate is calculated and parameterized and implications of the new results on nova nucleosynthesis are thoroughly discussed.

  11. A theoretical study of problems in classical nova evolution

    International Nuclear Information System (INIS)

    Shankar, A.

    1990-01-01

    Three distinct issues in classical nova evolution are addressed with the aid of one- and two-dimensional numerical hydrodynamics. The effects of convection on nova outbursts are examined within the confines of the mixing length theory. It is found that increasing the efficiency of convection enhances the violence of the thermonuclear runaway (TNR). This also relates to the question of the feasibility of obtaining nova outbursts on magnetic white dwarfs among the AM Her systems. The effects of a strong magnetic field on the TNR are explored. The field interferes with the development of convection during the TNR, which results in lower ejection velocities. However, for field strengths typical of cataclysmic variables, the violence of strong outbursts is affected only moderately. The conditions necessary for the production of strong TNR's in the hibernation model of cataclysmic binary evolution are also examined. The feasibility of obtaining strong nova outbursts is investigated when the accretion rate during hibernation is decreased. It is found that a reduction (by a factor of 100) for periods of longer than a couple thousand years, is sufficient to ensure violent outbursts, even in the presence of large pre-outburst accretion rates. The effects of a common envelope phase (CEP) on the outburst are discussed. The motion of the secondary through an expanding common envelope is resisted by frictional drag. This dissipates both energy and angular momentum from the orbit inducing hydrodynamic motion. Significant departures are found to occur in the manner in which mass is lost when the effects of drag are taken into account. Specifically, a CEP is found to accelerate and enhance mass loss. Ejection is found to be concentrated in the orbital plane, with velocities of a few thousand km/sec

  12. Big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Boyd, Richard N.

    2001-01-01

    The precision of measurements in modern cosmology has made huge strides in recent years, with measurements of the cosmic microwave background and the determination of the Hubble constant now rivaling the level of precision of the predictions of big bang nucleosynthesis. However, these results are not necessarily consistent with the predictions of the Standard Model of big bang nucleosynthesis. Reconciling these discrepancies may require extensions of the basic tenets of the model, and possibly of the reaction rates that determine the big bang abundances

  13. Tourism Development Plan for Nova Lima, MG/BR: A Case Study

    Directory of Open Access Journals (Sweden)

    Porto Aluisio Finazzi

    2014-01-01

    Full Text Available The project called “Tourism Development Plan of Nova Lima, MG” was a labor required by the city of Nova Lima, through the Secretary of Municipal Tourism. The municipality of Nova Lima has numerous tourist attractions or potential for them attractive, and is developing a work of public policies aimed at structuring this activity. The objective of this project was to offer to its population, as well as the government and the private sector, the assurance of quality activity according to the international, national and state the assumptions referred to in the Municipal Tourism Plan. All work was developed by Scientific and Technical Research Data Collection, which took into consideration the participation of local stakeholders in the development of tourism through public hearings with the Section for Local Tourism, making use of Information from the Current Municipal Development Plan for Nova Lima and its Secretary of Tourism. We also note that the study was conducted in accordance with the guidelines and considerations of the Municipal Tourism Council (COMTUR of Nova Lima.

  14. a Synoptic Study of AN X-Ray Nova in Outburst

    Science.gov (United States)

    McClintock, Jeffrey

    Optical studies of X-ray novae in quiescence have yielded compelling evidence for black holes in binary systems. However, X-ray studies in quiescence are severely constrained by the near absence of high energy emission. Thus, further observational advances in black hole astrophysics require a substantial commitment to observe X-ray novae in outburst in just that spectral range accessible to XTE. We propose an agressive campaign of X-ray observations of the next non-pulsing X-ray nova that rises above 3 Crab at 2-10 keV. We further propose a coordinated and intensive campaign of optical and radio observations covering both hemispheres. The observations will provide a full temporal and spectral view of the outburst cycle.

  15. Study of the Quasi-Elastic Scattering in the NOvA Detector Prototype

    Energy Technology Data Exchange (ETDEWEB)

    Betancourt, Minerba [Univ. of Minnesota, Minneapolis, MN (United States)

    2013-06-01

    NOvA is a 810 km long base-line neutrino oscillation experiment with two detectors (far 14 KTon and near detector 300 Ton) currently being installed in the NUMI o -axis neutrino beam produced at Fermilab. A 222 Ton prototype NOvA detector (NDOS) was built and operated in the neutrino beam for over a year to understand the response of the detector and its construction. The goal of this thesis is to study the muon neutrino interaction data collected in this test, specifically the identification of quasi-elastic charged-current interactions and measure the behavior of the quasi-elastic muon neutrino cross section.

  16. Nucleosynthesis in stellar explosions

    Energy Technology Data Exchange (ETDEWEB)

    Woosley, S.E.; Axelrod, T.S.; Weaver, T.A.

    1983-01-01

    The final evolution and explosion of stars from 10 M/sub solar/ to 10/sup 6/ M/sub solar/ are reviewed with emphasis on factors affecting the expected nucleosynthesis. We order our paper in a sequence of decreasing mass. If, as many suspect, the stellar birth function was peaked towards larger masses at earlier times (see e.g., Silk 1977; but also see Palla, Salpeter, and Stahler 1983), this sequence of masses might also be regarded as a temporal sequence. At each stage of Galactic chemical evolution stars form from the ashes of preceding generations which typically had greater mass. A wide variety of Type I supernova models, most based upon accreting white dwarf stars, are also explored using the expected light curves, spectra, and nucleosynthesis as diagnostics. No clearly favored Type I model emerges that is capable of simultaneously satisfying all three constraints.

  17. Nucleosynthesis in stellar explosions

    International Nuclear Information System (INIS)

    Woosley, S.E.; Axelrod, T.S.; Weaver, T.A.

    1983-01-01

    The final evolution and explosion of stars from 10 M/sub solar/ to 10 6 M/sub solar/ are reviewed with emphasis on factors affecting the expected nucleosynthesis. We order our paper in a sequence of decreasing mass. If, as many suspect, the stellar birth function was peaked towards larger masses at earlier times (see e.g., Silk 1977; but also see Palla, Salpeter, and Stahler 1983), this sequence of masses might also be regarded as a temporal sequence. At each stage of Galactic chemical evolution stars form from the ashes of preceding generations which typically had greater mass. A wide variety of Type I supernova models, most based upon accreting white dwarf stars, are also explored using the expected light curves, spectra, and nucleosynthesis as diagnostics. No clearly favored Type I model emerges that is capable of simultaneously satisfying all three constraints

  18. Corrections to primordial nucleosynthesis

    International Nuclear Information System (INIS)

    Dicus, D.A.; Kolb, E.W.; Gleeson, A.M.; Sudarshan, E.C.G.; Teplitz, V.L.; Turner, M.S.

    1982-01-01

    The changes in primordial nucleosynthesis resulting from small corrections to rates for weak processes that connect neutrons and protons are discussed. The weak rates are corrected by improved treatment of Coulomb and radiative corrections, and by inclusion of plasma effects. The calculations lead to a systematic decrease in the predicted 4 He abundance of about ΔY = 0.0025. The relative changes in other primoridal abundances are also 1 to 2%

  19. Nucleosynthesis in Supernovae

    Science.gov (United States)

    Thielemann, Friedrich-Karl; Isern, Jordi; Perego, Albino; von Ballmoos, Peter

    2018-04-01

    We present the status and open problems of nucleosynthesis in supernova explosions of both types, responsible for the production of the intermediate mass, Fe-group and heavier elements (with the exception of the main s-process). Constraints from observations can be provided through individual supernovae (SNe) or their remnants (e.g. via spectra and gamma-rays of decaying unstable isotopes) and through surface abundances of stars which witness the composition of the interstellar gas at their formation. With a changing fraction of elements heavier than He in these stars (known as metallicity) the evolution of the nucleosynthesis in galaxies over time can be determined. A complementary way, related to gamma-rays from radioactive decays, is the observation of positrons released in β+-decays, as e.g. from ^{26}Al, ^{44}Ti, ^{56,57}Ni and possibly further isotopes of their decay chains (in competition with the production of e+e- pairs in acceleration shocks from SN remnants, pulsars, magnetars or even of particle physics origin). We discuss (a) the role of the core-collapse supernova explosion mechanism for the composition of intermediate mass, Fe-group (and heavier?) ejecta, (b) the transition from neutron stars to black holes as the final result of the collapse of massive stars, and the relation of the latter to supernovae, faint supernovae, and gamma-ray bursts/hypernovae, (c) Type Ia supernovae and their nucleosynthesis (e.g. addressing the ^{55}Mn puzzle), plus (d) further constraints from galactic evolution, γ-ray and positron observations. This is complemented by the role of rare magneto-rotational supernovae (related to magnetars) in comparison with the nucleosynthesis of compact binary mergers, especially with respect to forming the heaviest r-process elements in galactic evolution.

  20. Shell and explosive hydrogen burning. Nuclear reaction rates for hydrogen burning in RGB, AGB and Novae

    Energy Technology Data Exchange (ETDEWEB)

    Boeltzig, A. [Gran Sasso Science Institute, L' Aquila (Italy); Bruno, C.G.; Davinson, T. [University of Edinburgh, SUPA, School of Physics and Astronomy, Edinburgh (United Kingdom); Cavanna, F.; Ferraro, F. [Dipartimento di Fisica, Universita di Genova (Italy); INFN, Genova (Italy); Cristallo, S. [Osservatorio Astronomico di Collurania, INAF, Teramo (Italy); INFN, Napoli (Italy); Depalo, R. [Dipartimento di Fisica e Astronomia, Universita di Padova, Padova (Italy); INFN, Padova (Italy); DeBoer, R.J.; Wiescher, M. [University of Notre Dame, Institute for Structure and Nuclear Astrophysics, Joint Institute for Nuclear Astrophysics, Notre Dame, Indiana (United States); Di Leva, A.; Imbriani, G. [Dipartimento di Fisica, Universita di Napoli Federico II, Napoli (Italy); INFN, Napoli (Italy); Marigo, P. [Dipartimento di Fisica e Astronomia, Universita di Padova, Padova (Italy); Terrasi, F. [Dipartimento di Matematica e Fisica Seconda Universita di Napoli, Caserta (Italy); INFN, Napoli (Italy)

    2016-04-15

    The nucleosynthesis of light elements, from helium up to silicon, mainly occurs in Red Giant and Asymptotic Giant Branch stars and Novae. The relative abundances of the synthesized nuclides critically depend on the rates of the nuclear processes involved, often through non-trivial reaction chains, combined with complex mixing mechanisms. In this paper, we summarize the contributions made by LUNA experiments in furthering our understanding of nuclear reaction rates necessary for modeling nucleosynthesis in AGB stars and Novae explosions. (orig.)

  1. Study of the 18F(p,α)15O reaction by transfer reaction for application to γ-ray emission from Novae

    International Nuclear Information System (INIS)

    Sereville, N. de

    2003-12-01

    The gamma emission from novae at/or below 511 keV is due to the annihilation of the positrons produced in the beta + decay of F 18 . The interpretation of this emission through observations made by the Integral satellite for instance, requires a good knowledge of F 18 nucleosynthesis. The reaction rate of the F 18 (p,α)O 15 is the least known because of 2 resonances corresponding to the levels 6.419 and 6.449 MeV of Ne 19 whose proton widths are completely unknown. We have determined these proton widths via the study of one-nucleon transfer reaction D(F 18 ,pα)N 15 populating equivalent levels in F 19 . We have used a 14 MeV F 18 radioactive beam on a CD 2 target for inverse kinematics studies and the multi-track silicon detector LEDA. A DWBA (Distorted Wave Bound Approximation) has enabled us to determine the proton width of both resonances and has showed that they have an impact in the calculation of the reaction rate. A thorough study of the remaining uncertainties of the reaction rate has been undertaken, particularly for those concerning interferences between these resonances and a higher resonance of Ne 19 . The reaction rate that we have obtained is very similar to the previous rate used but now it rests on a more solid basis

  2. Near-infrared and optical studies of the highly obscured nova V1831 Aquilae (Nova Aquilae 2015)

    Science.gov (United States)

    Banerjee, D. P. K.; Srivastava, Mudit K.; Ashok, N. M.; Munari, U.; Hambsch, F.-J.; Righetti, G. L.; Maitan, A.

    2018-01-01

    Near-infrared (NIR) and optical photometry and spectroscopy are presented for the nova V1831 Aquilae, covering the early decline and dust-forming phases during the first ∼90 d after its discovery. The nova is highly reddened due to interstellar extinction. Based solely on the nature of the NIR spectrum, we are able to classify the nova to be of the Fe II class. The distance and extinction to the nova are estimated to be 6.1 ± 0.5 kpc and Av ∼ 9.02, respectively. Lower limits of the electron density, emission measure and ionized ejecta mass are made from a Case B analysis of the NIR Brackett lines, while the neutral gas mass is estimated from the optical [O I] lines. We discuss the cause of the rapid strengthening of the He I 1.0830-μm line during the early stages. V1831 Aql formed a modest amount of dust fairly early (∼19.2 d after discovery); the dust shell is not seen to be optically thick. Estimates of the dust temperature, dust mass and grain size are made. Dust formation commences around day 19.2 at a condensation temperature of 1461 ± 15 K, suggestive of a carbon composition, following which the temperature is seen to decrease gradually to 950 K. The dust mass shows a rapid initial increase, which we interpret as being due to an increase in the number of grains, followed by a period of constancy, suggesting the absence of grain destruction processes during this latter time. A discussion of the evolution of these parameters is made, including certain peculiarities seen in the grain radius evolution.

  3. Isotopic studies of rare gases in terrestrial samples and in natural nucleosynthesis

    International Nuclear Information System (INIS)

    Reynolds, J.H.

    1988-08-01

    This project is concerned with research in rare gas mass spectrometry. The broad objective is to read the natural record that isotopes of the rare gases comprise as trace constituents of natural gases, rocks, and meteorites. In past years, these interests have led to the study of such diverse problems as the dating of rocks, the early chronology and isotopic structure of the solar system as revealed by extinct radioactivities, and the elemental and isotopic composition of trapped primordial rare gases in meteorites. In recent years, the project has focused progressively more on terrestrial problems

  4. Isotopic studies of rare gases in terrestrial samples and in natural nucleosynthesis

    International Nuclear Information System (INIS)

    1987-07-01

    This project is concerned with research in rare gas mass spectrometry. The broad objective is to read the natural record that isotopes of the rare gases comprise as trace constituents of natural gases, rocks, and meteorites. In past years, these interests have led to the study of such diverse problems as the dating of rocks, the early chronology and isotopic structure of the solar system as revealed by extinct radioactivities, and the elemental and isotopic composition of trapped primordial rare gases in meteorites. In recent years, the project has focused progressively more on terrestrial problems

  5. Underground Study of Big Bang Nucleosynthesis in the Precision Era of Cosmology

    Directory of Open Access Journals (Sweden)

    Gustavino Carlo

    2017-01-01

    Full Text Available Big Bang Nucleosinthesis (BBN theory provides definite predictions for the abundance of light elements produced in the early universe, as far as the knowledge of the relevant nuclear processes of the BBN chain is accurate. At BBN energies (30 ≲ Ecm ≲ 300 MeV the cross section of many BBN processes is very low because of the Coulomb repulsion between the interacting nuclei. For this reason it is convenient to perform the measurements deep underground. Presently the world’s only facility operating underground is LUNA (Laboratory for Undergound Nuclear astrophysics at LNGS (“Laboratorio Nazionale del Gran Sasso”, Italy. In this presentation the BBN measurements of LUNA are briefly reviewed and discussed. It will be shown that the ongoing study of the D(p, γ3He reaction is of primary importance to derive the baryon density of universe Ωb with high accuracy. Moreover, this study allows to constrain the existence of the so called “dark radiation”, composed by undiscovered relativistic species permeating the universe, such as sterile neutrinos.

  6. Underground Study of Big Bang Nucleosynthesis in the Precision Era of Cosmology

    Science.gov (United States)

    Gustavino, Carlo

    2017-03-01

    Big Bang Nucleosinthesis (BBN) theory provides definite predictions for the abundance of light elements produced in the early universe, as far as the knowledge of the relevant nuclear processes of the BBN chain is accurate. At BBN energies (30 ≲ Ecm ≲ 300 MeV) the cross section of many BBN processes is very low because of the Coulomb repulsion between the interacting nuclei. For this reason it is convenient to perform the measurements deep underground. Presently the world's only facility operating underground is LUNA (Laboratory for Undergound Nuclear astrophysics) at LNGS ("Laboratorio Nazionale del Gran Sasso", Italy). In this presentation the BBN measurements of LUNA are briefly reviewed and discussed. It will be shown that the ongoing study of the D(p, γ)3He reaction is of primary importance to derive the baryon density of universe Ωb with high accuracy. Moreover, this study allows to constrain the existence of the so called "dark radiation", composed by undiscovered relativistic species permeating the universe, such as sterile neutrinos.

  7. Isotopic studies of rare gases in terrestrial samples and natural nucleosynthesis

    International Nuclear Information System (INIS)

    1990-07-01

    This project is concerned with research in rare gas mass spectrometry. We read the natural record that isotopes of the rare gases provide. We study fluids using a system (RARGA) that is sometimes deployed in the field. In 1990 there was a strong effort to reduce the backlog of RARGA samples on hand, so that it was a year of intensive data gathering. Samples from five different areas in the western United States and samples from Guatemala and Australia were analyzed. In a collaborative study we also began analyzing noble gases from rocks associated with the fluids. An important objective, continuing in 1991, is to understand better the reasons for somewhat elevated 3 He/ 4 He ratios in regions where there is no contemporary volcanism which could produce the effect by addition of mantle helium. Our helium data have given us and our collaborators some insights, which are to be followed up, into gold mineralization in geothermal regions. Our DOE work in calibrating a sensitive laser microprobe mass spectrometer for noble gases in fluid inclusions continues. Having completed a series of papers on noble gases in diamonds, we next will attempt to make precise isotopic measurements on xenon from mantle sources, in search of evidence for terrestrially elusive 244 Pu decay

  8. Isotopic studies of rare gases in terrestrial samples and natural nucleosynthesis

    International Nuclear Information System (INIS)

    Reynolds, J.H.

    1991-01-01

    This project is concerned with research in rare gas mass spectrometry. We read the natural record that isotopes of the rate gases provide. We study fluids using a system (RARGA) that is sometimes deployed in the field. In 1990 there was a strong effort to reduce the backlog of RARGA samples on hand, so that it was a year of intensive data gathering. Samples from five different areas in the Western United States and samples from Guatemala and Australia were analyzed. In a collaborative study we also began analyzing noble gases from rocks associated with the fluids. An important objective, continuing in 1991, is to understand better the reasons for somewhat elevated 3 He/ 4 He ratios in regions where there is no contemporary volcanism which could produce the effect by addition of mantle helium. Our helium data have given us and our collaborators some insights, which are to be followed up, into gold mineralization in geothermal regions. Our DOE work in calibrating a sensitive laser microprobe mass spectrometer for noble gases in fluid inclusions continues. Having completed a series of papers on noble gases in diamonds, we next will attempt to make precise isotopic measurements on xenon from mantle sources in search of evidence for terrestrially elusive 244 Pu decay. 41 refs., 3 figs

  9. Isotopic studies of rare gases in terrestrial samples and natural nucleosynthesis

    International Nuclear Information System (INIS)

    1991-05-01

    This project is concerned with research in rare gas mass spectrometry. Using a two-pronged attack, we study fluids using a system (RARGA) designed for fluid analysis in bulk which is sometimes deployed in the field and a laser microprobe mass spectrometer for fluid inclusion studies. In 1991 the RARGA project continued monitoring helium isotope variations associated with renewed seismic activity in Long Valley Caldera and expanded our geothermal data base to include Lassen National Park. An important objective, continuing in 1992, is to understand better the reasons for somewhat elevated 3 He/ 4 He ratios in regions where there is no contemporary volcanism which could produce the effect by addition of mantle helium. To this end, 1991 saw continued efforts to understand variations in composition between fluids and associated reservoir rocks and extended the data base to include fluids from the Gulf of Mexico. Our DOE work in calibrating a sensitive laser microprobe mass spectrometer for noble gases in fluid inclusions continues with successful returns particularly in calibrating neutron irradiated samples for tracing halogen ratios. In connection with observations of neutron-produced noble gas nuclides in granites, we have begun comparing measurements with calculations for both thermal and epithermal neutrons. We submitted a third paper on noble gases in diamonds, concentrating on observed effects of 4 He, 3 He, and fission xenon implantation from nuclear processes in adjacent material in the matrix rock. 16 refs., 1 tab

  10. Big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Fields, Brian D.; Olive, Keith A.

    2006-01-01

    We present an overview of the standard model of big bang nucleosynthesis (BBN), which describes the production of the light elements in the early universe. The theoretical prediction for the abundances of D, 3 He, 4 He, and 7 Li is discussed. We emphasize the role of key nuclear reactions and the methods by which experimental cross section uncertainties are propagated into uncertainties in the predicted abundances. The observational determination of the light nuclides is also discussed. Particular attention is given to the comparison between the predicted and observed abundances, which yields a measurement of the cosmic baryon content. The spectrum of anisotropies in the cosmic microwave background (CMB) now independently measures the baryon density to high precision; we show how the CMB data test BBN, and find that the CMB and the D and 4 He observations paint a consistent picture. This concordance stands as a major success of the hot big bang. On the other hand, 7 Li remains discrepant with the CMB-preferred baryon density; possible explanations are reviewed. Finally, moving beyond the standard model, primordial nucleosynthesis constraints on early universe and particle physics are also briefly discussed

  11. Nucleosynthesis of 26Al

    International Nuclear Information System (INIS)

    Casse, M.

    1986-07-01

    A burst of interest has followed the discovery in the galactic plane of the 1.8 MeV gamma line attached to the decay of 26 Al. We discuss the relative merits of supernovae, novae, massive and supermassive mass-losing stars as potential sources of this expressive isotope

  12. Nucleosynthesis in Core-Collapse Supernovae

    Science.gov (United States)

    Stevenson, Taylor Shannon; Viktoria Ohstrom, Eva; Harris, James Austin; Hix, William R.

    2018-01-01

    The nucleosynthesis which occurs in core-collapse supernovae (CCSN) is one of the most important sources of elements in the universe. Elements from Oxygen through Iron come predominantly from supernovae, and contributions of heavier elements are also possible through processes like the weak r-process, the gamma process and the light element primary process. The composition of the ejecta depends on the mechanism of the explosion, thus simulations of high physical fidelity are needed to explore what elements and isotopes CCSN can contribute to Galactic Chemical Evolution. We will analyze the nucleosynthesis results from self-consistent CCSN simulations performed with CHIMERA, a multi-dimensional neutrino radiation-hydrodynamics code. Much of our understanding of CCSN nucleosynthesis comes from parameterized models, but unlike CHIMERA these fail to address essential physics, including turbulent flow/instability and neutrino-matter interaction. We will present nucleosynthesis predictions for the explosion of a 9.6 solar mass first generation star, relying both on results of the 160 species nuclear reaction network used in CHIMERA within this model and on post-processing with a more extensive network. The lowest mass iron core-collapse supernovae, like this model, are distinct from their more massive brethren, with their explosion mechanism and nucleosynthesis being more like electron capture supernovae resulting from Oxygen-Neon white dwarves. We will highlight the differences between the nucleosynthesis in this model and more massive supernovae. The inline 160 species network is a feature unique to CHIMERA, making this the most sophisticated model to date for a star of this type. We will discuss the need and mechanism to extrapolate the post-processing to times post-simulation and analyze the uncertainties this introduces for supernova nucleosynthesis. We will also compare the results from the inline 160 species network to the post-processing results to study further

  13. Photinos and primordial nucleosynthesis

    International Nuclear Information System (INIS)

    Salati, P.

    1986-07-01

    Photinos are among the most interesting particles predicted by supersymmetric theories. If they exist they should influence in many ways the results of the primordial nucleosynthesis i.e. the predicted primordial abundances of D, 3 He, 4 He (and 7 Li). If photinos are stable, cosmological constraints restrict their possible mass to be either very light (M∼ γ γ > a few GeV), depending on the slepton and squark masses. In the case where photinos are unstable, they could create high energy photons able to photodisintegrate the light elements. The comparison between the predicted and the observed abundances allows to restrict significantly the photino mass-lifetime range: roughly speaking photinos of relatively high mass (M∼ γ > 150 MeV) and low time scale ( 3 sec) are compatible with these abundances

  14. A flickering study of nova-like systems KR Aur and UU Aqr

    Science.gov (United States)

    Dobrotka, A.; Mineshige, S.; Casares, J.

    2012-03-01

    We present a study of the flickering activity in two nova-like systems, KR Aur and UU Aqr. We applied a statistical model of flickering simulations in accretion discs based on turbulent angular momentum transport between two adjacent rings with an exponential distribution of the turbulence dimension scale. The model is based on a steady-state disc model, which is satisfied in the case of hot ionized discs of nova-like cataclysmic variables. Our model successfully fits the observed power-density spectrum of KR Aur with the disc parameter α= 0.10-0.40 and an inner-disc truncation radius in the range Rin= 0.88-1.67 × 109 cm. The exact values depend on the mass-transfer rate in the sense that α decreases and Rin increases with mass-transfer rate. In any case, the inner-disc radius found for KR Aur is considerably smaller than those for quiescent dwarf novae, as predicted by the disc instability model. On the other hand, our simulations fail to reproduce the power-density spectrum of UU Aqr. A tantalizing explanation involves the possible presence of spiral waves, which are expected in UU Aqr because of its low mass ratio but not in KR Aur. In general our model predicts the observed concentration of flickering in the central disc. We explain this by the radial dependence of the angular-momentum gradient.

  15. Study of the 2H(p,γ)3He reaction in the Big Bang Nucleosynthesis energy range at LUNA

    Science.gov (United States)

    Mossa, Viviana

    2018-01-01

    Deuterium is the first nucleus produced in the Universe, whose accumulation marks the beginning of the so called Big Bang Nucleosynthesis (BBN). Its primordial abundance is very sensitive to some cosmological parameters like the baryon density and the number of the neutrino families. Presently the main obstacle to an accurate theoretical deuterium abundance evaluation is due to the poor knowledge of the 2H(p,γ)3He cross section at BBN energies. The aim of the present work is to describe the experimental approach proposed by the LUNA collaboration, whose goal is to measure, with unprecedented precision, the total and the differential cross section of the reaction in the 30 < Ec.m. [keV] < 300 energy range.

  16. Symbiotic Novae

    OpenAIRE

    Mikolajewska, Joanna

    2010-01-01

    The symbiotic novae are thermonuclear novae in symbiotic binary systems -- interacting binaries with evolved red giant donors, and the longest orbital periods. This paper aims at presenting physical characteristics of these objects and discussing their place among the whole family of symbiotic stars.

  17. Neutrinos and nucleosynthesis in supernova

    Energy Technology Data Exchange (ETDEWEB)

    Solis, U [Instituto de Ciencias Nucleares, Departamento de Fisica de Altas EnergIas, Universidad Nacional Autonoma de Mexico (ICN-UNAM). Apartado Postal 70-543, 04510 Mexico, D.F. (Mexico); D' Olivo, J C [Instituto de Ciencias Nucleares, Departamento de Fisica de Altas EnergIas, Universidad Nacional Autonoma de Mexico (ICN-UNAM). Apartado Postal 70-543, 04510 Mexico, D.F. (Mexico); Cabral-Rosetti, L G [Departamento de Posgrado, Centro Interdisciplinario de Investigacion y Docencia en Educacion Tecnica (CIIDET), Av. Universidad 282 Pte., Col. Centro, A. Postal 752, C.P. 76000, Santiago de Queretaro, Qro. (Mexico)

    2006-05-15

    The type II supernova is considered as a candidate site for the production of heavy elements. The nucleosynthesis occurs in an intense neutrino flux, we calculate the electron fraction in this environment.

  18. Neutrinos and nucleosynthesis in supernova

    International Nuclear Information System (INIS)

    Solis, U; D'Olivo, J C; Cabral-Rosetti, L G

    2006-01-01

    The type II supernova is considered as a candidate site for the production of heavy elements. The nucleosynthesis occurs in an intense neutrino flux, we calculate the electron fraction in this environment

  19. Big-Bang Nucleosynthesis

    CERN Document Server

    Fields, Brian D.; Sarkar, Subir

    2014-01-01

    A critical review is given of the current status of cosmological nucleosynthesis. In the framework of the Standard Model with 3 types of relativistic neutrinos, the baryon-to-photon ratio, η, corresponding to the inferred primordial abundances of deuterium and helium-4 is consistent with the independent determination of η from observations of anisotropies in the cosmic microwave background. However the primordial abundance of lithium-7 inferred from observations is significantly below its expected value. Taking systematic uncertainties in the abundance estimates into account, there is overall concordance in the range η=(5.7−6.7)×10−10 at 95% CL (corresponding to a cosmological baryon density ΩBh2=0.021−0.025). The D and He-4 abundances, when combined with the CMB determination of η, provide the bound Nν=3.28±0.28 on the effective number of neutrino species. Other constraints on new physics are discussed briefly.

  20. Development of a β-delayed charged particle detector for studying novae and x-ray bursts

    Science.gov (United States)

    Friedman, Moshe; Budner, Tamas; Cortesi, Marco; Harris, Madison; Janasik, Molly; Perez-Loureiro, David; Pollaco, Emmanuel; Roosa, Michael; Tiwari, Pranjal; Wrede, Chris; Yurkon, John

    2017-09-01

    Classical novae and type I x-ray bursts are energetic and common thermonuclear astrophysical explosions. However, our ability to understand these events is limited by the lack of comprehensive nuclear data on proton-rich nuclei. Specifically, constraining the 30P(p , γ) 31S and 15O(α , γ) 19N e reaction rates has been found to be crucial to the understanding of nucleosynthesis and energy generation in these events. As direct measurements of these reactions are not technically feasible at the present time, a gas-filled detector of β-delayed charged particles has been designed and built to measure the 31Cl(βp) 30P and 20Mg(βpα) 15O decay sequences at NSCL, providing an indirect probe of resonances in the radiative capture reactions above. The detector is coupled with the Segmented Germanium Array (SeGA) to enable coincidence γ detection, as an additional probe of interaction details and for normalization purposes. The first phase of the detector functions as a proton calorimeter and it is currently being tested and optimized. We will describe the technical status of Phase I, including the concept, simulations, design, assembly, and first offline measurements using radioactive sources. This work is supported by NSF Grant No. PHY-1102511 and DOE Award No. DE-SC0016052.

  1. Isotopic 32S/33S ratio as a diagnostic of presolar grains from novae

    Directory of Open Access Journals (Sweden)

    A. Parikh

    2014-10-01

    Full Text Available Measurements of sulphur isotopes in presolar grains can help to identify the astrophysical sites in which these grains were formed. A more precise thermonuclear rate of the 33S(p,γ34Cl reaction is required, however, to assess the diagnostic ability of sulphur isotopic ratios. We have studied the 33S(3He,d34Cl proton-transfer reaction at 25 MeV using a high-resolution quadrupole–dipole–dipole–dipole magnetic spectrograph. Deuteron spectra were measured at ten scattering angles between 10° and 55°. Twenty-four levels in 34Cl over Ex=4.6–5.9 MeV were observed, including three levels for the first time. Proton spectroscopic factors were extracted for the first time for levels above the 33S + p threshold, spanning the energy range required for calculations of the thermonuclear 33S(p,γ34Cl rate in classical nova explosions. We have determined a new 33S(p,γ34Cl rate using a Monte Carlo method and have performed new hydrodynamic nova simulations to determine the impact on nova nucleosynthesis of remaining nuclear physics uncertainties in the reaction rate. We find that these uncertainties lead to a factor of ≤5 variation in the 33S(p,γ34Cl rate over typical nova peak temperatures, and variation in the ejected nova yields of SCa isotopes by ≤20%. In particular, the predicted 32S/33S ratio is 110–130 for the nova model considered, compared to 110–440 with previous rate uncertainties. As recent type II supernova models predict ratios of 130–200, the 32S/33S ratio may be used to distinguish between grains of nova and supernova origin.

  2. Bioindicator and fish health studies around the Terra Nova oil development site on the Grand Banks

    Energy Technology Data Exchange (ETDEWEB)

    Mathieu, A.; Hanlon, J.; Melvin, W.; French, B. [Oceans Ltd., St. John' s, NL (Canada); DeBlois, E. [Elisabeth DeBlois Inc., St. John' s, NL (Canada); Williams, U.; Wight, F.; Janes, G. [Petro-Canada, St. John' s, NL (Canada)

    2009-07-01

    Bioindicators or health effect indicators can be a valuable reconnaissance tool for addressing concerns on the part of the fishing industry and public interests regarding any potential impacts of pollutants on fish stocks. American plaice (Hippoglossoides platessoides) was initially chosen by the oil industry as an indicator species for Environmental Effects Monitoring (EEM) programs in the Grand Banks of Newfoundland because it is an important commercial flatfish. This presentation reported on fish health studies carried out at the Terra Nova development site before and after release of produced waters, which began in 2003. These studies represented 1 component of the overall Terra Nova EEM program. Fish were collected near the development area and in a reference area 20 km away. A broad range of health effect indicators were studied, including fish condition, visible skin and organ lesions, levels of mixed-function oxygenase (MFO) enzymes, haematology and an array of 19 histopathological indices in liver and gills. These indicators have been widely used in laboratory and field investigations with various fish species. A slight elevation of MFO enzyme activity was observed in fish from the development area in 2002, before release of produced water. In 2006, other indices were similar between the development and reference area. It was concluded that the overall results do not indicate any project effects.

  3. Supernova neutrinos and explosive nucleosynthesis

    Science.gov (United States)

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Mathews, G. J.; Nakamura, K.; Shibagaki, S.; Suzuki, T.

    2014-05-01

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes 7Li, 11B, 92Nb, 138La and 180Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and θ13, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements 11B and 7Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ13, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  4. Supernova neutrinos and explosive nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J.; Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Nakamura, K. [Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Suzuki, T. [Department of Physics, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-05-09

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and θ{sub 13}, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements {sup 11}B and {sup 7}Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ{sub 13}, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  5. Novae news

    CERN Document Server

    2012-01-01

    As announced in the previous Bulletin, Novae has opened a new snack bar on the Flagstaff car park, just a few metres from CERN's reception area (Building 33).   Just a few metres from the CERN Reception, the new Novae snack point welcomes visitors and CERNois. Opening hours Currently: Monday to Friday, 8 a.m. to 4 p.m. From September: Monday to Friday, 7:45 a.m. to 5 p.m.; Saturdays from 8 a.m. to 2 p.m. The snack bar selection includes breakfast, starting at 2.70 CHF, cold dishes from 5 CHF, and hot dishes from 6 CHF.   Novae has also installed a 24-hour-a-day food vending machine in the CERN hostel (Building 39) and in Building 13. You can buy pasta and cooked dishes for 6.50 CHF to 8 CHF. In addition, a groceries vending machine has been installed in the main building, just across from the news kiosk. Nearly 60 different items are available around the clock. Finally, Novae has introduced a new payment system in several buildings on the Meyrin site. It accepts credit ca...

  6. Studies of neutrino asymmetries generated by ordinary-sterile neutrino oscillations in the early Universe and implications for big bang nucleosynthesis bounds

    Energy Technology Data Exchange (ETDEWEB)

    Foot, R.; Volkas, R.R. [Research Centre for High Energy Physics, School of Physics, University of Melbourne, Parkville, 3052 (Australia)

    1997-04-01

    Ordinary-sterile neutrino oscillations can generate a significant lepton number asymmetry in the early Universe. We study this phenomenon in detail. We show that the dynamics of ordinary-sterile neutrino oscillations in the early Universe can be approximately described by a single integrodifferential equation which we derive from both the density matrix and Hamiltonian formalisms. This equation reduces to a relatively simple ordinary first-order differential equation if the system is sufficiently smooth (static limit). We study the conditions for which the static limit is an acceptable approximation. We also study the effect of the thermal distribution of neutrino momenta on the generation of lepton number. We apply these results to show that it is possible to evade (by many orders of magnitude) the big bang nucleosynthesis (BBN) bounds on the mixing parameters {delta}m{sup 2} and sin{sup 2}2{theta}{sub 0} describing ordinary-sterile neutrino oscillations. We show that the large angle or maximal vacuum oscillation solution to the solar neutrino problem does not significantly modify BBN for most of the parameter space of interest, provided that the {tau} and/or {mu} neutrinos have masses greater than about 1 eV. We also show that the large angle or maximal ordinary-sterile neutrino oscillation solution to the atmospheric neutrino anomaly does not significantly modify BBN for a range of parameters. {copyright} {ital 1997} {ital The American Physical Society}

  7. Nuclear reaction rates and the nova outburst

    International Nuclear Information System (INIS)

    Starrfield, S.G.; Iliadis, C.

    2000-01-01

    In this paper we examined the consequences of improving the nuclear reaction library on our simulations of TNRs on 1.25M, WD and 1.35M, WDS. We have found that the changes in the rates have affected the nucleosynthesis predictions of our calculations but not, to any great extent, the gross features. In addition, we have used a lower mass accretion rate than in our previous studies in order to accrete (and eject) more material. This has, as expected, caused the peak values of some important parameters to increase over our previous studies at the same WD mass. However, because some important reaction rates have declined in the new compilation this has not increased the abundances for nuclei above aluminum and, in fact, they have declined while the abundances of both 26 Al and 27 Al have increased at both WD masses. In contrast, the abundance of 22 Na has declined at both WD masses over the values predicted in our earlier work. This has important implications with respect to predictions of the observability of novae with INTEGRAL

  8. Crédito Carbono: um estudo de caso na empresa NovaGerarCarbon Credit: a Case Study at the NovaGerar CompanyCrédito Carbono: un estudio de caso en la empresa NovaGerar

    Directory of Open Access Journals (Sweden)

    BITO, Nelson Satio

    2006-05-01

    Full Text Available RESUMOO Protocolo de Quioto, firmado em dezembro de 1997, é um instrumento importante na diminuição das emissões de gases de efeito estufa e na busca de desenvolvimento sustentável. Os países desenvolvidos que aderiram ao Protocolo assumiram o compromisso de reduzir suas emissões de gases em 5,2% (base 1.990 no período de 2.008 a 2.012. Das três modalidades para a diminuição do custo dos investimentos na redução dos gases, este artigo tem por objeto o estudo do Crédito Carbono previsto no Mecanismo de Desenvolvimento Limpo - MDL, voltado para países em desenvolvimento no trato das questões ambientais através do qual são implementados projetos que trazem resultados positivos. O objetivo deste artigo é estudar o Projeto NovaGerar desenvolvido em Nova Iguaçu – RJ, procurando investigar se o incentivo do Crédito Carbono, previsto no MDL, contribuiu para sua viabilidade econômica e, conseqüentemente, reduziu impactos ambientais por meio de reduções de gases do efeito estufa. A análise dos dados demonstrou que o projeto não se mostrou viável, quando enfocou somente a geração de energia elétrica. Agregando-se o Crédito de Carbono, mostrou-se atrativo com a expressiva taxa interna de retorno de 36,19% ao ano.ABSTRACT The Kyoto Protocol, signed on December 1977, is an important instrument for reducing greenhouse gas emissions and for pursuing sustainable development. The developed countries that adhered to the Protocol committed themselves to reduce their gas emissions by 5.2% (data-base 1990 during the 2008-2012 period. Of the three modalities for diminishing gas reduction investment costs, this article aims at studying the Carbon Credit instrument foreseen in the Clean Development Mechanism – CDM, which has been designed for handling environmental issues by developing countries, whereby projects that bring positive results are implemented. The purpose of this article is to study the NovaGerar Project developed in

  9. Experimental study of the 'NOVA' Z-pinch equipment working as vacuum-gap

    International Nuclear Information System (INIS)

    Acuna, H.; Bernal, L.; Cortazar, D.; Iglesias, G.; Pouzo, J.

    1990-01-01

    The Z-pinch device 'NOVA' (2 kjoule, 10 kV, 250 kA) is operated as a vacuum gap. The plasma is generated in high vacuum (10 -5 mb) by the material let loose from the copper electrodes. Many strong compressions (micro pinches) are produced in the pinch column over the first quarter of the current period. This is detected by the observable pulses in the dI/dt signal. Hard X-rays generated in coincidence with the micro pinches are detected using a scintillator-photomultiplier system. This work studies the plasma evolution, by taking pictures of the pinch with obturation times of about 15 ns, temporally correlated with the dI/dt signal. Instabilities of types m=0 and m=1 are observed. (Author). 3 refs., 6 figs

  10. Spectral and photometric study of the symbiotic nova RS ophiuchus in quiet phase

    Science.gov (United States)

    Kondratyeva, L.; Rspaev, F.; Krugov, M.; Serebryanskiy, A.

    2017-07-01

    The results of spectral and photometric study of the recurrent Nova RS Ophiuchus are presented and discussed. Observations were carried out in 2009-2016. During these eight years the fluxes of HI and FeII emission lines have slightly decreased by a factor of 3 - 4. Hα and Hβ exhibit double-peaked profiles with a central absorption. The ratio of the blue and red peaks intensities(V/R) varies from 0.3 to 1.0 for Hβ and from 0.4 to 0.7 for Hα. Possible correlations between changes of the ratio and other spectral parameters were investigated. Dependence of V/R on the radial velocity of absorbtion component is found out.

  11. Experimental studies of interaction mechanisms and phase transport processes in two-phase flow (NOVA program); Experimentelle Untersuchung von Wechselwirkungsmechanismen und Phasentransportprozessen in Zweiphasenstroemungen (NOVA-Vorhaben)

    Energy Technology Data Exchange (ETDEWEB)

    Sauter, H.; Meyder, R.; Philipp, P.; Samstag, M.

    1995-08-01

    The NOVA program was continued with turbulent, vertical, upward two-phase flow experiments. The development of a local gas distribution along the test section was visualized by X-ray tomography. (orig.)

  12. Bossa Nova

    DEFF Research Database (Denmark)

    Petersen, Nicoline Jacoby; Bræstrup, Lise

    "Bossa Nova" giver dig de bedste bud på, hvordan du takler den menneskelige dimension i ledelse. Når du bevæger dig ud på gulvet, opstår der konflikter, kærlighed, jalousi og vrede. Pludselig opdager du, at medarbejdere tænker meget anderledes end dig selv, har forskellige behov og af og til......, kriser og meget andet. Her er værdifulde iagttagelser og tips, som enhver leder ? uanset branche ? kan bruge i sin dagligdag. "Bossa Nova" er uundværlig for den, der vil lære mere om, hvordan man får mennesker til at præstere det sublime, så ledelse bliver en dans, hvor alle kan følge takten....

  13. Experimental studies of interaction mechanisms and phase transport processes in two-phase flow (NOVA program)

    International Nuclear Information System (INIS)

    Sauter, H.; Meyder, R.; Philipp, P.; Samstag, M.

    1995-01-01

    The NOVA program was continued with turbulent, vertical, upward two-phase flow experiments. The development of a local gas distribution along the test section was visualized by X-ray tomography. (orig.)

  14. Optical and Near-infrared Study of Nova V2676 Oph 2012

    Energy Technology Data Exchange (ETDEWEB)

    Raj, A. [Korea Astronomy and Space Science Institute, Daejeon, 34055 (Korea, Republic of); Das, R. K. [Department of Astrophysics and Cosmology, S N Bose National Centre for Basic Sciences, Salt Lake, Kolkata 700106 (India); Walter, F. M., E-mail: ashish.raj@iiap.res.in [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

    2017-02-01

    We present optical spectrophotometric and near-infrared (NIR) photometric observations of the nova V2676 Oph covering the period from 2012 March 29 through 2015 May 8. The optical spectra and photometry of the nova have been taken from SMARTS and Asiago; the NIR photometry was obtained from SMARTS and Mt. Abu. The spectra were dominated by strong H i lines from the Balmer series, Fe ii, N i, and [O i] lines in the initial days, typical of an Fe ii type nova. The measured FWHM for the H β and H α lines was 800–1200 km s{sup −1}. There was pronounced dust formation starting 90 days after the outburst. The J − K color was the largest among recent dust-forming novae.

  15. Nucleosynthesis confronts an unstable inert 17 keV state

    International Nuclear Information System (INIS)

    Enqvist, K.; Kainulainen, K.; Thomson, M.

    1991-01-01

    We study the cosmological consequences of an inert 17 keV state mixing with the electron neutrino. We find that the nucleosynthesis upper bound on the primordial helium abundance prohibits the existence of such a state, unless its lifetime falls into the range 6x10 -4 s vac -2 s. In this range the decay occurs after the chemical decoupling of the electron neutrinos and before the beginning of the nucleosynthesis, with the result that the predicted helium abundance can be lower than what it would be in the standard scenario. (orig.)

  16. Magnetic novae

    Science.gov (United States)

    Zemko, Polina; Orio, Marina

    2016-07-01

    We present the results of optical and X-ray observations of two quiescent novae, V2491 Cyg and V4743 Sgr. Our observations suggest the intriguing possibility of localization of hydrogen burning in magnetic novae, in which accretion is streamed to the polar caps. V2491 Cyg was observed with Suzaku more than 2 years after the outburst and V4743 Sgr was observed with XMM Newton 2 and 3.5 years after maximum. In the framework of a monitoring program of novae previously observed as super soft X-ray sources we also obtained optical spectra of V4743 Sgr with the SALT telescope 11.5 years after the eruption and of V2491 Cyg with the 6m Big Azimutal Telescope 4 and 7 years post-outburst. In order to confirm the possible white dwarf spin period of V2491 Cyg measured in the Suzaku observations we obtained photometric data using the 90cm WIYN telescope at Kitt Peak and the 1.2 m telescope in Crimea. We found that V4743 Sgr is an intermediate polar (IP) and V2491 Cyg is a strong IP candidate. Both novae show modulation of their X-ray light curves and have X-ray spectra typical of IPs. The Suzaku and XMM Newton exposures revealed that the spectra of both novae have a very soft blackbody-like component with a temperature close to that of the hydrogen burning white dwarfs in their SSS phases, but with flux by at least two orders of magnitude lower, implying a possible shrinking of emitting regions in the thin atmosphere that is heated by nuclear burning underneath it. In quiescent IPs, independently of the burning, an ultrasoft X-ray flux component originates at times in the polar regions irradiated by the accretion column, but the soft component of V4743 Sgr disappeared in 2006, indicating that the origin may be different from accretion. We suggest it may have been due to an atmospheric temperature gradient on the white dwarf surface, or to continuing localized thermonuclear burning at the bottom of the envelope, before complete turn-off. The optical spectra of V2491 Cyg and V

  17. Study of the {sup 18}F(p,{alpha}){sup 15}O reaction by transfer reaction for application to {gamma}-ray emission from Novae; Etude de la reaction {sup 18}F(p,{alpha}){sup 15}O par reaction de transfert pour application a l'emission {gamma} des Novae

    Energy Technology Data Exchange (ETDEWEB)

    Sereville, N. de

    2003-12-15

    The gamma emission from novae at/or below 511 keV is due to the annihilation of the positrons produced in the beta + decay of F{sup 18}. The interpretation of this emission through observations made by the Integral satellite for instance, requires a good knowledge of F{sup 18} nucleosynthesis. The reaction rate of the F{sup 18}(p,{alpha})O{sup 15} is the least known because of 2 resonances corresponding to the levels 6.419 and 6.449 MeV of Ne{sup 19} whose proton widths are completely unknown. We have determined these proton widths via the study of one-nucleon transfer reaction D(F{sup 18},p{alpha})N{sup 15} populating equivalent levels in F{sup 19}. We have used a 14 MeV F{sup 18} radioactive beam on a CD{sub 2} target for inverse kinematics studies and the multi-track silicon detector LEDA. A DWBA (Distorted Wave Bound Approximation) has enabled us to determine the proton width of both resonances and has showed that they have an impact in the calculation of the reaction rate. A thorough study of the remaining uncertainties of the reaction rate has been undertaken, particularly for those concerning interferences between these resonances and a higher resonance of Ne{sup 19}. The reaction rate that we have obtained is very similar to the previous rate used but now it rests on a more solid basis.

  18. Primordial nucleosynthesis revisited via Trojan Horse Results

    Directory of Open Access Journals (Sweden)

    Pizzone R.G.

    2016-01-01

    Full Text Available Big Bang Nucleosynthesis (BBN requires several nuclear physics inputs and nuclear reaction rates. An up-to-date compilation of direct cross sections of d(d,pt, d(d,n3He and 3He(d,p4He reactions is given, being these ones among the most uncertain bare-nucleus cross sections. An intense experimental effort has been carried on in the last decade to apply the Trojan Horse Method (THM to study reactions of relevance for the BBN and measure their astrophysical S(E-factor. The reaction rates and the relative error for the four reactions of interest are then numerically calculated in the temperature ranges of relevance for BBN (0.01nucleosynthesis calculations in order to evaluate their impact on the calculated primordial abundances of D, 3,4He and 7Li. These were compared with the observational primordial abundance estimates in different astrophysical sites. A comparison was also performed with calculations using other reaction rates compilations available in literature.

  19. Educational Technology Program for Nova Scotia: Initial Phase. A Report on the Federal-Provincial Study of Educational Technology in Nova Scotia.

    Science.gov (United States)

    deVille, Barry, Ed.

    This is a preliminary examination of the present status and future prospects of educational technology in Nova Scotian schools. It is aimed at developing a plan to enhance the quality of educational technology by concentrating on systems which will be conducive to realizing educational goals at a reasonable cost. An overview of the institutional…

  20. Inhomogeneous Big Bang Nucleosynthesis Revisited

    OpenAIRE

    Lara, J. F.; Kajino, T.; Mathews, G. J.

    2006-01-01

    We reanalyze the allowed parameters for inhomogeneous big bang nucleosynthesis in light of the WMAP constraints on the baryon-to-photon ratio and a recent measurement which has set the neutron lifetime to be 878.5 +/- 0.7 +/- 0.3 seconds. For a set baryon-to-photon ratio the new lifetime reduces the mass fraction of He4 by 0.0015 but does not significantly change the abundances of other isotopes. This enlarges the region of concordance between He4 and deuterium in the parameter space of the b...

  1. Regional Patterns of Ethnicity in Nova Scotia: A Geographical Study. Ethnic Heritage Series, Volume VI.

    Science.gov (United States)

    Millward, Hugh A.

    In this sixth volume of the Ethnic Heritage Series, the pattern of ethnicity in Nova Scotia (Canada) is examined by deriving indices of diversity for counties and larger towns. The historical development of ethnic patterns from 1767 to 1971 and recent changes in the ethnic pattern are discussed. Ethnic origin data is mapped for 1871 and 1971 and…

  2. Heavy-element nucleosynthesis

    International Nuclear Information System (INIS)

    Mathews, G.J.

    1990-01-01

    New measurements and theoretical studies of nuclear properties, together with new astronomical data on the growth of heavy-element abundances during the early history of the Galaxy, now provide a clearer picture of where in nature the elements heavier than iron are produced by rapid (r-process) and show (s-process) neutron capture reactions. The nuclear data suggest that the r-process involves a high-neutron-density beta-flow equilibrium environment and that the s-process may have occurred at a temperature and neutron density consistent with a 13 C(α,n) 16 0 neutron source. The astronomical data, when compared with simple galactic chemical evolution modes, suggests that the r-process is associated with type II supernovae and that the neutron source must be manufactured by the star. Low-mass type II supernovae are proposed as the most important contributors to the r-process. A 13 C neutron source in intermediate-mass stars is proposed for the s-process. 64 refs., 7 figs

  3. NEAR-IR STUDIES OF RECURRENT NOVA V745 SCORPII DURING ITS 2014 OUTBURST

    International Nuclear Information System (INIS)

    Banerjee, D. P. K.; Joshi, Vishal; Venkataraman, V.; Ashok, N. M.; Raj, A.; Marion, G. H.; Hsiao, E. Y.

    2014-01-01

    The recurrent nova V745 Scorpii underwent its third known outburst on 2014 February 6. Infrared monitoring of the eruption on an almost daily basis, starting from 1.3 days after discovery, shows the emergence of a powerful blast wave generated by the high velocity nova ejecta exceeding 4000 km s –1 plowing into its surrounding environment. The temperature of the shocked gas is raised to a high value exceeding 10 8 K immediately after outburst commencement. The energetics of the outburst clearly surpass those of similar symbiotic systems like RS Oph and V407 Cyg which have giant secondaries. The shock does not show a free-expansion stage but rather shows a decelerative Sedov-Taylor phase from the beginning. Such strong shock fronts are known to be sites for γ-ray generation. V745 Sco is the latest nova, apart from five other known novae, to show γ-ray emission. It may be an important testbed to resolve the crucial question of whether or not all novae are generically γ-ray emitters by virtue of having a circumbinary reservoir of material that is shocked by the ejecta rather than γ-ray generation being restricted to only symbiotic systems with a shocked red giant (RG) wind. The lack of a free-expansion stage favors V745 Sco to have a density enhancement around the white dwarf (WD), above that contributed by a RG wind. Our analysis also suggests that the WD in V745 Sco is very massive and a potential progenitor for a future SN Ia explosion

  4. Creating Cohesive Community Through Shared Reading: A Case Study of One Book Nova Scotia

    Directory of Open Access Journals (Sweden)

    Alyssa Harder

    2015-06-01

    Full Text Available One Book Nova Scotia is described on the program’s website as “a province-wide community reading event for adults.” Formally programmed events have included the book announcement and launch, a series of author readings, and book discussions, both face to face and through Twitter. This paper analyzes the success of the One Book Nova Scotia program in achieving its goals of developing a reading culture and community in the province of Nova Scotia based on the findings of a participant survey, distributed in both 2012 and 2013, and an analysis of the 2013 Twitter discussion. This analysis reveals that participants tended to be well-educated females, aged 50-59, and often employed in libraries, bookselling or publishing, or news media. The goal of developing or participating in a reading community was a compelling motivator for many respondents. Although many respondents indicated their desire to be part of a reading community, Twitter was not proven to be an effective forum for fostering conversation or debate related to One Book Nova Scotia. Building on the analysis, the paper concludes with some recommendations to improve the effectiveness of future programs. These recommendations include the selection of a book with strong regional connections, an expansion of publicity methods, an increase in lead time between the announcement of the book title and the start of programming, and a more strategic use of Twitter as a discussion forum. Although these recommendations arise from the specific analysis of the One Book Nova Scotia reading program, they are general enough to apply to other One Book, One Community programs.

  5. Study of the 17Ne Coulomb dissociation process and its role for the rp process of nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Marganiec, Justyna [TU Darmstadt (Germany); EMMI, GSI Darmstadt (Germany); Wamers, Felix [EMMI, GSI Darmstadt (Germany); TU Darmstadt (Germany); GSI Darmstadt (Germany); FIAS, Frankfurt am Main (Germany); Aumann, Thomas [TU Darmstadt (Germany); GSI Darmstadt (Germany); Egorova, Irina [BLTP JINR Dubna (Russian Federation); Grigorenko, Leonid [FLNR JINR Dubna (Russian Federation); RRC KI, Moscow (Russian Federation); Heil, Michael [GSI Darmstadt (Germany); Perfenova, Yuliya [FLNR JINR Dubna (Russian Federation); INP, Moscow (Russian Federation); Plag, Ralf [GSI Darmstadt (Germany); Goethe-Universitaet, Frankfurt am Main (Germany); Collaboration: R3B-Collaboration

    2014-07-01

    The study of {sup 17}Ne Coulomb dissociation process gives us a possibility to study the time-reversed reaction {sup 15}O(2p,γ){sup 17}Ne, with the detailed balance theorem. This reaction could serve as a bypass of {sup 15}O waiting point during the rp process, and move the initial CNO material towards heavier nuclei. The two-proton capture can proceed sequentially or directly from the three-body continuum. And the reaction rate can be enhanced by a few orders of magnitude by taking the three-body continuum into account. The Coulomb dissociation method is the one way to experimentally determine the three-body radiative capture cross section, which is needed to verify theoretical calculations, and which was not experimentally determined yet. The experiment has been performed at the LAND/R3B setup at GSI.

  6. Electron Capture Cross Sections for Stellar Nucleosynthesis

    Directory of Open Access Journals (Sweden)

    P. G. Giannaka

    2015-01-01

    Full Text Available In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasiparticle random-phase approximation (pn-QRPA and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the abovementioned e--capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the 66Zn isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

  7. Isotope ratio in stellar atmospheres and nucleosynthesis

    International Nuclear Information System (INIS)

    Barbuy, B.L.S.

    1987-01-01

    The determination of isotopic ratios in stellar atmospheres is studied. The isotopic shift of atomic and molecular lines of different species of a certain element is examined. CH and MgH lines are observed in order to obtain the 12 C: 13 C and 24 Mg: 25 Mg: 26 Mg isotpic ratios. The formation of lines in stellar atmospheres is computed and the resulting synthetic spectra are employed to determine the isotopic abundances. The results obtained for the isotopic ratios are compared to predictions of nucleosynthesis theories. Finally, the concept of primary and secondary element is discussed, and these definitions are applied to the observed variations in the abundance of elements as a function of metallicity. (author) [pt

  8. From (p)reheating to nucleosynthesis

    International Nuclear Information System (INIS)

    Jedamzik, Karsten

    2002-01-01

    This paper gives a brief qualitative description of the possible evolution of the early universe between the end of an inflationary epoch and the end of big-bang nucleosynthesis. After a general introduction, establishing the minimum requirements cosmologists impose on this cosmic evolutionary phase, namely, successful baryogenesis, the production of cosmic dark matter and successful light-element nucleosynthesis, a more detailed discussion on some recent developments follows. This latter includes the physics of preheating, the putative production of (alternative) dark matter and the current status of big bang nucleosynthesis

  9. Late baryogenesis faces primordial nucleosynthesis

    International Nuclear Information System (INIS)

    Delbourgo-Salvador, P.; Audouze, J.; Salati, P.

    1991-11-01

    Since the sphalleron mechanism present in the standard theory of electro-weak interactions violates B+L, models have been suggested where baryogenesis takes place at late epochs and is concomitant with primordial nucleosynthesis. The possibility for the baryon asymmetry to be generated was numerically investigated at the same time as the light elements are cooked. The primordial yields of D, 3 He, 4 He and 7 Li were shown to exceed the upper limits inferred from observation, unless baryogenesis is anterior to the freeze-out of the weak interactions. This implies strong constraints on scenarios where the baryon asymmetry originates from the late decay of massive gravitinos. (author) 18 refs., 6 figs

  10. Nucleosynthesis in Jets from Collapsars

    International Nuclear Information System (INIS)

    Fujimoto, Shin-ichiro; Nishimura, Nobuya; Hashimoto, Masa-aki

    2008-01-01

    We investigate nucleosynthesis inside magnetically driven jets ejected from collapsars, or rotating magnetized stars collapsing to a black hole, based on two-dimensional magnetohydrodynamic simulation of the collapsars during the core collapse. We follow the evolution of the abundances of about 4000 nuclides from the collapse phase to the ejection phase using a large nuclear reaction network. We find that the r-process successfully operates only in the energetic jets (>10 51 erg), so that U and Th are synthesized abundantly, even when the collapsars have a relatively small magnetic field (10 10 G) and a moderately rotating core before the collapse. The abundance patterns inside the jets are similar to that of the r-elements in the solar system. The higher energy jets have larger amounts of 56 Ni. Less energetic jets, which have small amounts of 56 Ni, could induce GRB without supernova, such as GRB060505 and GRB060614

  11. Big Bang nucleosynthesis in crisis?

    International Nuclear Information System (INIS)

    Hata, N.; Scherrer, R.J.; Steigman, G.; Thomas, D.; Walker, T.P.; Bludman, S.; Langacker, P.

    1995-01-01

    A new evaluation of the constraint on the number of light neutrino species (N ν ) from big bang nucleosynthesis suggests a discrepancy between the predicted light element abundances and those inferred from observations, unless the inferred primordial 4 He abundance has been underestimated by 0.014±0.004 (1σ) or less than 10% (95% C.L.) of 3 He survives stellar processing. With the quoted systematic errors in the observed abundances and a conservative chemical evolution parametrization, the best fit to the combined data is N ν =2.1±0.3 (1σ) and the upper limit is N ν ν =3) at the 98.6% C.L. copyright 1995 The American Physical Society

  12. Toward public volume database management: a case study of NOVA, the National Online Volumetric Archive

    Science.gov (United States)

    Fletcher, Alex; Yoo, Terry S.

    2004-04-01

    Public databases today can be constructed with a wide variety of authoring and management structures. The widespread appeal of Internet search engines suggests that public information be made open and available to common search strategies, making accessible information that would otherwise be hidden by the infrastructure and software interfaces of a traditional database management system. We present the construction and organizational details for managing NOVA, the National Online Volumetric Archive. As an archival effort of the Visible Human Project for supporting medical visualization research, archiving 3D multimodal radiological teaching files, and enhancing medical education with volumetric data, our overall database structure is simplified; archives grow by accruing information, but seldom have to modify, delete, or overwrite stored records. NOVA is being constructed and populated so that it is transparent to the Internet; that is, much of its internal structure is mirrored in HTML allowing internet search engines to investigate, catalog, and link directly to the deep relational structure of the collection index. The key organizational concept for NOVA is the Image Content Group (ICG), an indexing strategy for cataloging incoming data as a set structure rather than by keyword management. These groups are managed through a series of XML files and authoring scripts. We cover the motivation for Image Content Groups, their overall construction, authorship, and management in XML, and the pilot results for creating public data repositories using this strategy.

  13. Linkage of the Canadian Study of Health and Aging to provincial administrative health care databases in Nova Scotia.

    Science.gov (United States)

    Yip, A M; Kephart, G; Rockwood, K

    2001-01-01

    The Canadian Study of Health and Aging (CSHA) was a cohort study that included 528 Nova Scotian community-dwelling participants. Linkage of CSHA and provincial Medical Services Insurance (MSI) data enabled examination of health care utilization in this subsample. This article discusses methodological and ethical issues of database linkage and explores variation in the use of health services by demographic variables and health status. Utilization over 24 months following baseline was extracted from MSI's physician claims, hospital discharge abstracts, and Pharmacare claims databases. Twenty-nine subjects refused consent for access to their MSI file; health card numbers for three others could not be retrieved. A significant difference in healthcare use by age and self-rated health was revealed. Linkage of population-based data with provincial administrative health care databases has the potential to guide health care planning and resource allocation. This process must include steps to ensure protection of confidentiality. Standard practices for linkage consent and routine follow-up should be adopted. The Canadian Study of Health and Aging (CSHA) began in 1991-92 to explore dementia, frailty, and adverse health outcomes (Canadian Study of Health and Aging Working Group, 1994). The original CSHA proposal included linkage to provincial administrative health care databases by the individual CSHA study centers to enhance information on health care utilization and outcomes of study participants. In Nova Scotia, the Medical Services Insurance (MSI) administration, which drew the sampling frame for the original CSHA, did not retain the list of corresponding health card numbers. Furthermore, consent for this access was not asked of participants at the time of the first interview. The objectives of this study reported here were to examine the feasibility and ethical considerations of linking data from the CSHA to MSI utilization data, and to explore variation in health

  14. Explosive hydrogen burning in novae

    International Nuclear Information System (INIS)

    Wiescher, M.; Goerres, J.; Thielemann, F.K.; Ritter, H.

    1986-01-01

    Recent observations (nova CrA 81 and Aql 82) reported large enhancements of element abundances beyond CNO nuclei in nova ejecta, which still wait for a clear theoretical explanation. Attempts to interprete these findings include scenarios like nova events on a O-Ne-Mg white dwarf or nuclear processing which enables the transfer of CNO material to heavier nuclei. In the present study we included all available nuclear information on proton-rich unstable nuclei, to update thermo-nuclear reaction rates in explosive hydrogen burning. They are applied in a systematic analysis of explosive hydrogen burning for a variety of temperature conditions, appropriate to nova explosions. We find that (a) for temperatures T>2 10 8 K, pre-existing material in Ne, Al, or Mg can be transferred to heavier nuclei following the flow pattern of a r(apid) p(roton-capture) process (b) for T> or approx.3.5 10 8 K CNO matter can be processed to heavier nuclei (in accordance with previous findings). On the basis of these results it seems unlikely that nova Aql 82 (which shows strong carbon and oxygen enrichment together with heavier elements) can be explained by a nova event on a bare O-Ne-Mg white dwarf but is rather a result of burning with T> or approx.3.5 10 8 K. An application to existing nova models shows a reduced 26 Al production, when compared to earlier predictions. Both conclusions, however, have to be verified by complete nova calculations which include the improved nuclear physics input, presented here. (orig.)

  15. Electron screening and its effects on big-bang nucleosynthesis

    International Nuclear Information System (INIS)

    Wang Biao; Bertulani, C. A.; Balantekin, A. B.

    2011-01-01

    We study the effects of electron screening on nuclear reaction rates occurring during the big-bang nucleosynthesis epoch. The sensitivity of the predicted elemental abundances on electron screening is studied in detail. It is shown that electron screening does not produce noticeable results in the abundances unless the traditional Debye-Hueckel model for the treatment of electron screening in stellar environments is enhanced by several orders of magnitude. This work rules out electron screening as a relevant ingredient to big-bang nucleosynthesis, confirming a previous study [see Itoh et al., Astrophys. J. 488, 507 (1997)] and ruling out exotic possibilities for the treatment of screening beyond the mean-field theoretical approach.

  16. Typical examples of classical novae

    Science.gov (United States)

    Hack, Margherita; Selvelli, Pierluigi; Bianchini, Antonio; Duerbeck, Hilmar W.

    1993-09-01

    Because of the very complicated individualistic behavior of each nova, we think it necessary to review the observations of a few well-observed individuals. We have selected a few objects of different speed classes, which have been extensively observed. They are: V1500 Cygni 1975, a very fast nova; V603 Aql 1918, fast nova; CP Pup 1942, fast nova; GK Per 1901, fast nova; V 1668 Cyg 1979, moderately fast nova; FH Ser 1970, slow nova; DQ Her 1934, slow nova; T Aur 1891, slow nova; RR Pic 1925, slow nova; and HR Del 1967, very slow nova.

  17. A study of CR-39 track response to charged particles from NOVA implosions

    International Nuclear Information System (INIS)

    Phillips, T.W.; Cable, M.D.; Hicks, D.G.; Li, C.K.; Petrasso, R.D.; Seguin, F.H.

    1996-01-01

    We have exposed CR-39 track recording material to a number of NOVA implosions. Radiation from the implosion passed through an array of ranging filters, which aided identification of the incident particles and their energies. The etching procedure was calibrated by including a piece of track exposed to DD protons from a small accelerator. For the same shots, we quantitatively compare the DD neutron yield with the DD proton yield determined from the track. In DT implosions, tracks produced by neutron interactions prevent observation of charged-particle tracks that are produced by the processes of knock-on, secondary or tertiary fusion

  18. Hydrodynamic Studies of the Evolution of Recurrent, Symbiotic and Dwarf Novae: the White Dwarf Components are Growing in Mass

    Directory of Open Access Journals (Sweden)

    Starrfield S.

    2012-06-01

    Full Text Available Symbiotic binaries are systems containing white dwarfs (WDs and red giants. Symbiotic novae are those systems in which thermonuclear eruptions occur on the WD components. These are to be distinguished from events driven by accretion disk instabilities analogous to dwarf novae eruptions in cataclysmic variable outbursts. Another class of symbiotic systems are those in which the WD is extremely luminous and it seems likely that quiescent nuclear burning is ongoing on the accreting WD. A fundamental question is the secular evolution of the WD. Do the repeated outbursts or quiescent burning in these accreting systems cause the WD to gain or lose mass? If it is gaining mass, can it eventually reach the Chandrasekhar Limit and become a supernova (a SN Ia if it can hide the hydrogen and helium in the system? In order to better understand these systems, we have begun a new study of the evolution of Thermonuclear Runaways (TNRs in the accreted envelopes of WDs using a variety of initial WD masses, luminosities and mass accretion rates. We use our 1-D hydro code, NOVA, which includes the new convective algorithm of Arnett, Meakin and Young, the Hix and Thielemann nuclear reaction solver, the Iliadis reaction rate library, the Timmes equation of state, and the OPAL opacities. We assume a solar composition (Lodders abundance distribution and do not allow any mixing of accreted material with core material. This assumption strongly influences our results. We report here (1 that the WD grows in mass for all simulations so that ‘steady burning’ does not occur, and (2 that only a small fraction of the accreted matter is ejected in some (but not all simulations. We also find that the accreting systems, before thermonuclear runaway, are too cool to be seen in X-ray searches for SN Ia progenitors.

  19. Towards the kinetic theory of inequilibrium cosmological nucleosynthesis

    International Nuclear Information System (INIS)

    Fillipov, S.S.; Sedelnikov, E.V.; Khlopov, M.Yu.

    1993-07-01

    The aim of the paper is to elaborate the framework for the possible effects of nucleosynthesis by inequilirbium particles on the radiation dominance stage. Based on such an analysis the sensitivity of the astrophysical data to the presence of the sources of inequilibrium particles in the early Universe can be studied, thus providing an effective tool to probe cosmological effects of syperhight energy physics. 6 refs

  20. Radiation of dwarf novae

    International Nuclear Information System (INIS)

    Bruch, A.

    1987-01-01

    The nature of dwarf novae with their components white dwarf star, cool star, accretion disk, boundary layer and hot spot is investigated. It is shown that very different physical states and processes occur in the components of dwarf novae. Spectroscopical and photometrical observations are carried out. For better understanding the radiation portions of the single dwarf novae components are separated from the total electromagnetic spectrum recieved from the dwarf novae. The model assumptions are compared with the observations and verified

  1. Big-bang nucleosynthesis revisited

    Science.gov (United States)

    Olive, Keith A.; Schramm, David N.; Steigman, Gary; Walker, Terry P.

    1989-01-01

    The homogeneous big-bang nucleosynthesis yields of D, He-3, He-4, and Li-7 are computed taking into account recent measurements of the neutron mean-life as well as updates of several nuclear reaction rates which primarily affect the production of Li-7. The extraction of primordial abundances from observation and the likelihood that the primordial mass fraction of He-4, Y(sub p) is less than or equal to 0.24 are discussed. Using the primordial abundances of D + He-3 and Li-7 we limit the baryon-to-photon ratio (eta in units of 10 exp -10) 2.6 less than or equal to eta(sub 10) less than or equal to 4.3; which we use to argue that baryons contribute between 0.02 and 0.11 to the critical energy density of the universe. An upper limit to Y(sub p) of 0.24 constrains the number of light neutrinos to N(sub nu) less than or equal to 3.4, in excellent agreement with the LEP and SLC collider results. We turn this argument around to show that the collider limit of 3 neutrino species can be used to bound the primordial abundance of He-4: 0.235 less than or equal to Y(sub p) less than or equal to 0.245.

  2. Neutrinos and Big Bang Nucleosynthesis

    Directory of Open Access Journals (Sweden)

    Gary Steigman

    2012-01-01

    Full Text Available According to the standard models of particle physics and cosmology, there should be a background of cosmic neutrinos in the present Universe, similar to the cosmic microwave photon background. The weakness of the weak interactions renders this neutrino background undetectable with current technology. The cosmic neutrino background can, however, be probed indirectly through its cosmological effects on big bang nucleosynthesis (BBN and the cosmic microwave background (CMB radiation. In this BBN review, focused on neutrinos and more generally on dark radiation, the BBN constraints on the number of “equivalent neutrinos” (dark radiation, on the baryon asymmetry (baryon density, and on a possible lepton asymmetry (neutrino degeneracy are reviewed and updated. The BBN constraints on dark radiation and on the baryon density following from considerations of the primordial abundances of deuterium and helium-4 are in excellent agreement with the complementary results from the CMB, providing a suggestive, but currently inconclusive, hint of the presence of dark radiation, and they constrain any lepton asymmetry. For all the cases considered here there is a “lithium problem”: the BBN-predicted lithium abundance exceeds the observationally inferred primordial value by a factor of ~3.

  3. Deuterium and big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Burles, S.

    2000-01-01

    Measurements of deuterium absorption in high redshift quasar absorption systems provide a direct inference of the deuterium abundance produced by big bang nucleosynthesis (BBN). With measurements and limits from five independent absorption systems, we place strong constraints on the primordial ratio of deuterium to hydrogen, (D/H) p = 3.4 ± 0.3 x 10 -5 [1,2]. We employ a direct numerical treatment to improve the estimates of critical reaction rates and reduce the uncertainties in BBN predictions of D/H and 7 Li/H by a factor of three[3] over previous efforts[4]. Using our measurements of (D/H) p and new BBN predictions, we find at 95% confidence the baryon density ρ b = (3.6 ± 0.4) x 10 -31 g cm -3 (Ω b h 2 65 = 0.045 ± 0.006 in units of the critical density), and cosmological baryon-photon ratio η = (5.1 ± 0.6) x 10 -10

  4. Cosmological lepton asymmetry, primordial nucleosynthesis and sterile neutrinos

    Science.gov (United States)

    Abazajian, Kevork; Bell, Nicole F.; Fuller, George M.; Wong, Yvonne Y. Y.

    2005-09-01

    We study post weak decoupling coherent active-sterile and active-active matter-enhanced neutrino flavor transformation in the early Universe. We show that flavor conversion efficiency at Mikheyev-Smirnov-Wolfenstein resonances is likely to be high (adiabatic evolution) for relevant neutrino parameters and energies. However, we point out that these resonances cannot sweep smoothly and continuously with the expansion of the Universe. We show how neutrino flavor conversion in this way can leave both the active and sterile neutrinos with nonthermal energy spectra, and how, in turn, these distorted energy spectra can affect the neutron-to-proton ratio, primordial nucleosynthesis, and cosmological mass/closure constraints on sterile neutrinos. We demonstrate that the existence of a light sterile neutrino which mixes with active neutrinos can change fundamentally the relationship between the cosmological lepton numbers and the primordial nucleosynthesis He4 yield.

  5. A spectroscopic study of the deeply eclipsing dwarf nova IP Peg

    International Nuclear Information System (INIS)

    Marsh, T.R.

    1988-01-01

    Spectrophotometry of the dwarf novae IP Peg during quiescence is presented. The spectra have broad, double peaked emission lines on a blue continuum, characteristic of high-inclination dwarf novae. The emission lines are 96 per cent eclipsed and the orbital hump, which is strong in the continuum, is much weaker in the lines. We introduce a method for the analysis of radial velocities of emission lines which corrects for bias caused by disc asymmetries, and we determine the geometrical and physical parameters of IP Peg. The masses of the white dwarf and red star are Msub(W) = 1.09 ± 0.10 solar masses and Msub(R) = 0.64 ± 0.09 solar masses, and the orbital inclination is i = 79.3 ± 0.9 0 . The secondary star which has a radius Rsub(R) 0.49 ± 0.03 solar radii, lies near the main sequence mass-radius relation. (author)

  6. Neon novae, recurrent novae, and type I supernovae

    International Nuclear Information System (INIS)

    Starrfield, S.; Sparks, W.M.; Truran, J.W.; Shaviv, G.; Illinois Univ., Urbana, IL; Technion-Israel Inst. of Tech., Haifa

    1989-01-01

    Over the past few years, we have been investigating the effects of accretion onto massive white dwarfs and its implications for their growth in mass toward the Chandrasekhar limit, in attempts to identify a possible relationship between SN I and novae. In our studies we have considered accretion at various mass accretion rates onto a variety of different white dwarf masses. We have found that there is a critical white dwarf mass above which a significant fraction of the accreted mass can remain on the white dwarf after the outburst. Below this value of the white dwarf mass, all of the accreted mass, plus core material dredged up into the envelope, is ejected as a result of the explosion. Our latest results include accretion and boundary layer heating produced by the infalling material. From these studies, we have identified some members of the class of recurrent novae, those involving a thermonuclear runaway, as the novae that are occurring on very massive white dwarfs and evolving toward an SN I explosion. One of the outgrowths of our uv studies of novae in outburst has been the identification of a class of novae which eject material that is very rich in the elements from oxygen to aluminum. We have shown that these outbursts occur on ONeMg white dwarfs, which are necessarily very massive white dwarfs. 11 refs

  7. An integrated approach to dam safety evaluation. A case study: Upper Lake Falls Dam, Nova Scotia, Canada

    International Nuclear Information System (INIS)

    Pelletier, P.M.; Rattue, D.A.; Brown, E.R.

    1990-01-01

    Upper Lake Falls Dam is located in southwestern Nova Scotia. It is the uppermost hydroelectric development in a series of six developments on the Mersey River. The total capacity of the Mersey River system is 42 MW. The reservoir of Upper Lake Falls, Lake Rossignol, is the largest in Nova Scotia with a total area of 66 square miles and a gross storage of 800,000 acre-feet. An overview is presented of the hydrologic and hydraulic investigations carried out for the dam, which is classified as having high hazard potential because of permanent village and urban developments located downstream. The general methodology adopted in the study consisted of the following: gathering and verifying all meteorologic and hydrologic data; evaluating the Probable Maximum Precipitation (PMP) assumed to occur over the basin, and of the antecedent conditions prior to the PMP; calibrating a watershed model on flood events generated by rainfall, and by a combination of snowmelt and rainfall, and verifying the model using additional hydrologic events; deriving the Probable Maximum Flood (PMF) using the PMP results simulated on the calibrated watershed model; hydrodynamic routing of the flood hydrograph through all the developments; dambreak analysis, following sequential or independent failures; and flood inundation mapping. Details are given of safety analysis of the earthfill and concrete dam structures, reservoir management and cost-benefit analyses. 7 refs., 8 figs., 1 tab

  8. The classical nova outburst

    International Nuclear Information System (INIS)

    Starrfield, S.G.

    1988-01-01

    The classical nova outburst occurs on the white dwarf component in a close binary system. Nova systems are members of the general class of cataclysmic variables and other members of the class are the Dwarf Novae, AM Her variables, Intermediate Polars, Recurrent Novae, and some of the Symbiotic variables. Although multiwavelength observations have already provided important information about all of these systems, in this review I will concentrate on the outbursts of the classical and recurrent novae and refer to other members of the class only when necessary. 140 refs., 1 tab

  9. A visible and infrared study of the eclipsing dwarf nova Oy Carinae

    International Nuclear Information System (INIS)

    Berriman, G.

    1984-01-01

    This paper presents three simultaneous visible (V) and infrared (J,H,K) light curves of the eclipsing dwarf nova binary system OY Carinae in quiescence. The infrared light curves show a secondary minimum, not seen in the visible, which is the ellipsoidal variations of the red dwarf and its eclipse by the accretion disc surrounding the white dwarf companion. The red star, an M dwarf, supplies between 30 and 60 per cent of the total light at J,H and K. This requires that the system is between 100 and 300 pc away. The infrared continuum of the accretion disc around the white dwarf companion comes largely from the optically thin gas giving rise to the emission lines seen in the visible and ultraviolet. (author)

  10. Nova diagnostics summary

    International Nuclear Information System (INIS)

    Slivinsky, V.W.; Drake, R.P.

    1985-01-01

    The authors intend that Nova be the best diagnosed ICF research facility in operation today. The authors experience in providing advanced diagnostics for previous laser systems will be extended at Nova, and will be challenged by the development of new instrumentation to diagnose the more advanced targets made possible by this powerful laser. Previous experience has shown that to understand target performance, the authors must have as complete a set of diagnostics as possible. The Nova diagnostics are divided into two sets: the basic set required for the initial Nova experiments and the more advanced set for later, generally more complex, experiments. The basic set will be operational for the first Nova shots; it was a Nova line item funded with Nova construction money. This basic set is presented in a table

  11. Primordial nucleosynthesis: A cosmological point of view

    International Nuclear Information System (INIS)

    Mathews, G. J.; Kajino, T.; Yamazaki, D.; Kusakabe, M.; Cheoun, M.-K.

    2014-01-01

    Primordial nucleosynthesis remains as one of the pillars of modern cosmology. It is the test-ing ground upon which all cosmological models must ultimately rest. It is our only probe of the universe during the first few minutes of cosmic expansion and in particular during the important radiation-dominated epoch. These lectures review the basic equations of space-time, cosmology, and big bang nucleosynthesis. We will then review the current state of observational constraints on primordial abundances along with the key nuclear reactions and their uncertainties. We summarize which nuclear measure-ments are most crucial during the big bang. We also review various cosmological models and their constraints. In particular, we summarize the constraints that big bang nucleosynthesis places upon the possible time variation of fundamental constants, along with constraints on the nature and origin of dark matter and dark energy, long-lived supersymmetric particles, gravity waves, and the primordial magnetic field

  12. Nucleosynthesis in cold white dwarf explosions

    International Nuclear Information System (INIS)

    Canal, R.; Hernanz, M.

    1986-01-01

    Type I supernovae (SNI) are generally thought to be the main contributors to the galactic nucleosynthesis of iron-peak elements and their yields of intermediate-mass elements may also be important. We concentrate here upon a different class of models, based on the explosion of cold, massive, partially solid white dwarfs. We show that such white dwarfs must be relatively frequent among SNI progenitors and how their hydrodynamics upon ignition is very different from that of hotter, fluid white dwarfs. The implications for nucleosynthesis are briefly discussed and some preliminary results are presented

  13. Explosive Nucleosynthesis in Different Ye Conditions

    International Nuclear Information System (INIS)

    Iwamoto, Nobuyuki; Umeda, Hideyuki; Nomoto, Ken'ichi; Tominaga, Nozomu; Thielemann, Friedrich-Karl; Hix, W. Raphael

    2006-01-01

    The influence of a large variation of Ye on explosive yield is investigated. We calculate nucleosynthesis with the initial electron fraction Ye ranging from 0.48 to 0.58 in explosive Si burning region in Population III, 25 M· supernovae. We obtain the significant overproduction of odd elements, K and Sc. In the Ye < 0.5 cases light p-process nuclei are enhanced. We find that the abundance pattern taken from arbitrary mixture of each nucleosynthesis yield in various values of Ye can reasonably explain that in observed extremely metal-poor stars

  14. Neutral currents, supernovae neutrinos, and nucleosynthesis

    International Nuclear Information System (INIS)

    Haxton, W.C.

    1988-01-01

    The inelastic interactions of neutrinos during stellar collapse and neutron star cooling are discussed. The primary mechanism for dissipative neutrino reactions is nuclear excitation by neutral current scattering, a process not included in standard descriptions of supernovae. Charge-current and neutral current ''preheating'' of iron lying outside the shock front appears to be significant in the few milliseconds near shock breakout. This could help produce a more energetic shock. During the cooling phase, the neutral current interactions of muon and taon neutrinos appear to be responsible for some interesting nucleosynthesis. I discuss two examples the production of fluorine and neutrino-induced r-process nucleosynthesis. 26 refs., 1 fig., 3 tabs

  15. Big bang nucleosynthesis - Predictions and uncertainties

    International Nuclear Information System (INIS)

    Krauss, L.M.; Romanelli, P.

    1990-01-01

    A detailed reexamination is made of primordial big-bang nucleosynthesis (BBN), concentrating on the data for the main nuclear reactions leading to the production of Li-7, He-3 and D, and on the neutron half-life, relevant for He-4 production. The new values for reaction rates and uncertainties are then used as input in a Monte Carlo analysis of big bang nucleosynthesis of light elements. This allows confidence levels for the predictions of the standard BBN model to be high. 70 refs

  16. Big bang nucleosynthesis constraints on bulk neutrinos

    International Nuclear Information System (INIS)

    Goh, H.S.; Mohapatra, R.N.

    2002-01-01

    We examine the constraints imposed by the requirement of successful nucleosynthesis on models with one large extra hidden space dimension and a single bulk neutrino residing in this dimension. We solve the Boltzmann kinetic equation for the thermal distribution of the Kaluza-Klein modes and evaluate their contribution to the energy density at the big bang nucleosynthesis epoch to constrain the size of the extra dimension R -1 ≡μ and the parameter sin 2 2θ which characterizes the mixing between the active and bulk neutrinos

  17. Moving Forward with School Nutrition Policies: A Case Study of Policy Adherence in Nova Scotia.

    Science.gov (United States)

    McIsaac, Jessie-Lee D; Shearer, Cindy L; Veugelers, Paul J; Kirk, Sara F L

    2015-12-01

    Many Canadian school jurisdictions have developed nutrition policies to promote health and improve the nutritional status of children, but research is needed to clarify adherence, guide practice-related decisions, and move policy action forward. The purpose of this research was to evaluate policy adherence with a review of online lunch menus of elementary schools in Nova Scotia (NS) while also providing transferable evidence for other jurisdictions. School menus in NS were scanned and a list of commonly offered items were categorized, according to minimum, moderate, or maximum nutrition categories in the NS policy. The results of the menu review showed variability in policy adherence that depended on food preparation practices by schools. Although further research is needed to clarify preparation practices, the previously reported challenges of healthy food preparations (e.g., cost, social norms) suggest that many schools in NS are likely not able to use these healthy preparations, signifying potential noncompliance to the policy. Leadership and partnerships are needed among researchers, policy makers, and nutrition practitioners to address the complexity of issues related to food marketing and social norms that influence school food environments to inspire a culture where healthy and nutritious food is available and accessible to children.

  18. Fred Hoyle, primary nucleosynthesis and radioactivity

    Science.gov (United States)

    Clayton, Donald D.

    2008-10-01

    Primary nucleosynthesis is defined as that which occurs efficiently in stars born of only H and He. It is responsible not only for increasing the metallicity of the galaxy but also for the most abundant gamma-ray-line emitters. Astrophysicists have inappropriately cited early work in this regard. The heavily cited B2FH paper (Burbidge et al., 1957) did not effectively address primary nucleosynthesis whereas Hoyle (Hoyle, 1954) had done so quite thoroughly in his infrequently cited 1954 paper. Even B2FH with Hoyle as coauthor seems strangely to not have appreciated what Hoyle (Hoyle, 1954) had achieved. I speculate that Hoyle must not have thoroughly proofread the draft written in 1956 by E.M. and G.R. Burbidge. The clear roadmap of primary nucleosynthesis advanced in 1954 by Hoyle describes the synthesis yielding the most abundant of the radioactive isotopes for astronomy, although that aspect was unrealized at the time. Secondary nucleosynthesis has also produced many observable radioactive nuclei, including the first gamma-ray-line emitter to be discovered in the galaxy and several others within stardust grains. Primary gamma-ray emitters would have been even more detectable in the early galaxy, when the birth rate of massive stars was greater; but secondary emitters, such as 26Al, would have been produced with smaller yield then owing to smaller abundance of seed nuclei from which to create them.

  19. Nuclear weak interactions, supernova nucleosynthesis and neutrino oscillation

    Science.gov (United States)

    Kajino, Toshitaka

    2013-07-01

    We study the nuclear weak response in light-to-heavy mass nuclei and calculate neutrino-nucleus cross sections. We apply these cross sections to the explosive nucleosynthesis in core-collapse supernovae and find that several isotopes of rare elements 7Li, 11B, 138La, 180Ta and several others are predominantly produced by the neutrino-process nucleosynthesis. We discuss how to determine the suitable neutrino spectra of three different flavors and their anti-particles in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. Light-mass nuclei like 7Li and 11B, which are produced in outer He-layer, are strongly affected by the neutrino flavor oscillation due to the MSW (Mikheyev-Smirnov-Wolfenstein) effect, while heavy-mass nuclei like 138La, 180Ta and r-process elements, which are produced in the inner O-Ne-Mg layer or the atmosphere of proto-neutron star, are likely to be free from the MSW effect. Using such a different nature of the neutrino-process nucleosynthesis, we study the neutrino oscillation effects on their abundances, and propose a new novel method to determine the unknown neutrino oscillation parameters, θ13 and mass hierarchy, simultaneously. There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced neutrino-process 11B and 7Li encapsulated in the grains. Combining the recent experimental constraints on θ13, we show that although the uncertainties are still large, our method hints at a marginal preference for an inverted neutrino mass hierarchy for the first time.

  20. Quark mass variation constraints from Big Bang nucleosynthesis

    International Nuclear Information System (INIS)

    Bedaque, Paulo F.; Luu, Thomas; Platter, Lucas

    2011-01-01

    We study the impact on the primordial abundances of light elements created by a variation of the quark masses at the time of Big Bang nucleosynthesis (BBN). In order to navigate through the particle and nuclear physics required to connect quark masses to binding energies and reaction rates in a model-independent way, we use lattice QCD data and a hierarchy of effective field theories. We find that the measured 4 He abundances put a bound of -1% q /m q q /m q .

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

    International Nuclear Information System (INIS)

    Kajino, T.

    1995-01-01

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

  2. Current rate of nucleosynthesis and its implications

    Energy Technology Data Exchange (ETDEWEB)

    Mallik, D C.V.

    1981-06-01

    Comparisons among stellar birthrate figures for stars of 05-9 and B0, 0.5 and 1 spectral type show that the current rate of nucleosynthesis is compatible with the idea of massive stars producing most of the metals only in the event that the stellar birthrate decreased with time. The current stellar evolution data, as well as observations, do not support the premise that intermediate mass stars are the source of the bulk of the nucleosynthesis in the galaxy. It is concluded that the limits of the Simple Model must be surpassed with the supposition of prompt initial enrichment, in order foo the stellar birthrate to be constant while the metals originate in the massive stars.

  3. Type Ia Supernovae: Energetics, Neutronization and Nucleosynthesis

    International Nuclear Information System (INIS)

    Truran, James W.; Calder, Alan C.; Townsley, Dean M.; Seitenzahl, Ivo R.; Peng, Fang; Vladimirova, Natalia; Lamb, Donald Q.; Brown, Edward F.

    2007-01-01

    The utility of Type Ia supernovae, not simply as probes of the distance scale but also as a means of constraining the properties of dark energy, demands a significant improvement in theoretical predictions of their properties in outburst. To this end, we have given substantial effort to quantifying the energetics and nucleosynthesis properties of deflagration fronts in the interiors of the putative carbon-oxygen white dwarf progenitors of Type Ia thermonuclear supernovae. We briefly review some essential features of our flame model and its properties in this paper and discuss its implications both for our multidimensional numerical simulations of SNe Ia and for nucleosynthesis (specifically 56Ni production) in SNe Ia and Galactic chemical evolution

  4. Neutrino mixing and big bang nucleosynthesis

    Science.gov (United States)

    Bell, Nicole

    2003-04-01

    We analyse active-active neutrino mixing in the early universe and show that transformation of neutrino-antineutrino asymmetries between flavours is unavoidable when neutrino mixing angles are large. This process is a standard Mikheyev-Smirnov-Wolfenstein flavour transformation, modified by the synchronisation of momentum states which results from neutrino-neutrino forward scattering. The new constraints placed on neutrino asymmetries eliminate the possibility of degenerate big bang nucleosynthesis.Implications of active-sterile neutrino mixing will also be reviewed.

  5. Photodisintegration of deuterium and big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Hara, K.Y.; Utsunomiya, H.; Goko, S.; Akimune, H.; Yamagata, T.; Ohta, M.; Toyokawa, H.; Kudo, K.; Uritani, A.; Shibata, Y.; Lui, Y.-W.; Ohgaki, H.

    2003-01-01

    Photodisintegration cross sections were measured for deuterium with Laser-Compton scattering γ beams at seven energies near threshold. Combined with the preceding data, R(E)=N a σv for the p(n,γ)D reaction is for the first time evaluated based on experimental data with 6% uncertainty in the energy region relevant to the big bang nucleosynthesis (BBN). The result confirms the theoretical evaluation on which the BBN in the precision era relies

  6. Bulk yields of nucleosynthesis from massive stars

    International Nuclear Information System (INIS)

    Arnett, W.D.

    1978-01-01

    Preliminary estimates are made of the absolute yields of abundant nuclei synthesized in observed stars. The compositions of nine helium stars of mass 3 or =10M/sub sun/ is estimated. A variety of choices for the initial mass function (IMF) are used to calculate the yield per stellar generation. For standard choices of the (IMF) the absolute and relative yields of 12 C, 16 O, 20 Ne, 24 Mg, the Si to Ca group, and the iron group agree with solar system values, to the accuracy of the calculations. The relative yields are surprisingly insensitive to the slope of the IMF. In a second approach, using standard estimates (Ostriker, Richstone, and Thuan) for the current rate of stellar death, I find the present rate of nucleosynthesis in the solar neighborhood to be about 10%of the average rate over galactic history. This result is consistent with many standard models of galactic evolution (for example, the Schmidt model in which star formation goes as gas density squared). It appears that if the star formation rate is high enough to produce the stars we see around us, then the nucleosynthesis rate is large enough to produce the processed nuclei (except 4 He) seen in those stars. The typical nucleosynthesis source is massive (Mapprox. =30 M/sub sun/); the death rate of such stars is a small fraction (3-10%) of recent estimates of the total rate of supernovae

  7. ToO Galactic Nova -- Michelle ``Quick Response''

    Science.gov (United States)

    Helton, L. Andrew; Woodward, Chick; Evans, Nye; Geballe, Tom; Spitzer Nova Team

    2006-08-01

    Stars are the engines of energy production and chemical evolution in our Universe, depositing radiative and mechanical energy into their environments and enriching the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CN) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. We propose to obtain mid-IR spectra of a new galactic CN in outburst to investigate aspects of the CN phenomenon including the in situ formation and mineralogy of nova dust and the elemental abundances resulting from thermonuclear runaway. Synoptic, high S/N Michelle spectra permit: 1) determination of the grain size distribution and mineral composition of nova dust; 2) estimation of chemical abundances of nova ejecta from coronal and other emission line spectroscopy; and 3) measurement of the density and masses of the ejecta. This Gemini `Target of Opportunity' initiative (trigger K=5- 8 mag, assuming adequate PWFS guide stars exist) complements our extensive Spitzer, Chandra, Swift, XMM-Newton CN DDT/ToO programs.

  8. Synoptic Mid-IR Spectra ToO Novae

    Science.gov (United States)

    Helton, L. Andrew; Woodward, Chick; Evans, Nye; Geballe, Tom; Spitzer Nova Team

    2007-02-01

    Stars are the engines of energy production and chemical evolution in our Universe, depositing radiative and mechanical energy into their environments and enriching the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CN) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. We propose to obtain mid-IR spectra of a new galactic CN in outburst to investigate aspects of the CN phenomenon including the in situ formation and mineralogy of nova dust and the elemental abundances resulting from thermonuclear runaway. Synoptic, high S/N Michelle spectra permit: 1) determination of the grain size distribution and mineral composition of nova dust; 2) estimation of chemical abundances of nova ejecta from coronal and other emission line spectroscopy; and 3) measurement of the density and masses of the ejecta. This Gemini `Target of Opportunity' initiative (trigger K=5- 8 mag, assuming adequate PWFS guide stars exist) complements our extensive Spitzer, Chandra, Swift, XMM-Newton CN DDT/ToO programs.

  9. Laboratory approaches of nuclear reactions involved in primordial and stellar nucleosynthesis

    International Nuclear Information System (INIS)

    Rolfs, C.; California Inst. of Tech., Pasadena

    1986-01-01

    Laboratory-based studies of primordial and stellar nucleosynthesis are reviewed, with emphasis on the nuclear reactions induced by charged particles. The analytical approach used to investigate nuclear reactions associated with stellar reactions is described, as well as the experimental details and procedures used to investigate nuclear reactions induced by charged particles. The present knowledge of some of the key reactions involved in primordial nucleosynthesis is discussed, along with the progress and problems of nuclear reactions involved in the hydrogen and helium burning phases of a star. Finally, a description is given of new experimental techniques which might be useful for future experiments in the field of nuclear astrophysics. (U.K.)

  10. Model Novaes for analysis of the productivity and efficiency of logistics operators in Brazil: a study of its applicability for the years 2005 and 2006

    Directory of Open Access Journals (Sweden)

    Emanuel Rodrigues Junqueira

    2008-07-01

    Full Text Available The study presents a proposal to upgrade the production function to evaluate the productivity and efficiency of Brazilians logistics operators, which was developed by Novaes in his study in 2000. The goal was identify if and how the variables used continued to explain the behavior of productivity of these companies. To achieve that goal, tests were performed with data of years for 2005 and 2006, provided by the Revista Tecnologística, and used the same statistical techniques developed in the previous study, the multiple regression. The previous study intended to help the competitive advantage of logistics operators attentive to the problem, through the methodology of analysis of competitors and to customers of this service along the supply chain management, interested in identifying companies with greater efficiency. The results indicate that the model developed by Novaes is not valid for the current reality of these companies. Key-words: productivity function; logistic operators; analysis of competitors and suppliers.

  11. Pilot study investigating ambient air toxics emissions near a Canadian kraft pulp and paper facility in Pictou County, Nova Scotia.

    Science.gov (United States)

    Hoffman, Emma; Guernsey, Judith R; Walker, Tony R; Kim, Jong Sung; Sherren, Kate; Andreou, Pantelis

    2017-09-01

    Air toxics are airborne pollutants known or suspected to cause cancer or other serious health effects, including certain volatile organic compounds (VOCs), prioritized by the US Environmental Protection Agency (EPA). While several EPA-designated air toxics are monitored at a subset of Canadian National Air Pollution Surveillance (NAPS) sites, Canada has no specific "air toxics" control priorities. Although pulp and paper (P&P) mills are major industrial emitters of air pollutants, few studies quantified the spectrum of air quality exposures. Moreover, most NAPS monitoring sites are in urban centers; in contrast, rural NAPS sites are sparse with few exposure risk records. The objective of this pilot study was to investigate prioritized air toxic ambient VOC concentrations using NAPS hourly emissions data from a rural Pictou, Nova Scotia Kraft P&P town to document concentration levels, and to determine whether these concentrations correlated with wind direction at the NAPS site (located southwest of the mill). Publicly accessible Environment and Climate Change Canada data (VOC concentrations [Granton NAPS ID: 31201] and local meteorological conditions [Caribou Point]) were examined using temporal (2006-2013) and spatial analytic methods. Results revealed several VOCs (1,3-butadiene, benzene, and carbon tetrachloride) routinely exceeded EPA air toxics-associated cancer risk thresholds. 1,3-Butadiene and tetrachloroethylene were significantly higher (p towns and contribute to poor health in nearby communities.

  12. The NOvA Technical Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Ayres, D.S.; Drake, G.R.; Goodman, M.C.; Grudzinski, J.J.; Guarino, V.J.; Talaga, R.L.; Zhao, A.; /Argonne; Stamoulis, P.; Stiliaris, E.; Tzanakos, G.; Zois, M.; /Athens U. /Caltech /UCLA /Fermilab /College de France /Harvard U. /Indiana U. /Lebedev Inst. /Michigan State U. /Minnesota U., Duluth /Minnesota U.

    2007-10-08

    Technical Design Report (TDR) describes the preliminary design of the NOvA accelerator upgrades, NOvA detectors, detector halls and detector sites. Compared to the March 2006 and November 2006 NOvA Conceptual Design Reports (CDR), critical value engineering studies have been completed and the alternatives still active in the CDR have been narrowed to achieve a preliminary technical design ready for a Critical Decision 2 review. Many aspects of NOvA described this TDR are complete to a level far beyond a preliminary design. In particular, the access road to the NOvA Far Detector site in Minnesota has an advanced technical design at a level appropriate for a Critical Decision 3a review. Several components of the accelerator upgrade and new neutrino detectors also have advanced technical designs appropriate for a Critical Decision 3a review. Chapter 1 is an Executive Summary with a short description of the NOvA project. Chapter 2 describes how the Fermilab NuMI beam will provide a narrow band beam of neutrinos for NOvA. Chapter 3 gives an updated overview of the scientific basis for the NOvA experiment, focusing on the primary goal to extend the search for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations and measure the sin{sup 2}(2{theta}{sub 13}) parameter. This parameter has not been measured in any previous experiment and NOvA would extend the search by about an order of magnitude beyond the current limit. A secondary goal is to measure the dominant mode oscillation parameters, sin{sup 2}(2{theta}{sub 23}) and {Delta}m{sub 32}{sup 2} to a more precise level than previous experiments. Additional physics goals for NOvA are also discussed. Chapter 4 describes the Scientific Design Criteria which the Fermilab accelerator complex, NOvA detectors and NOvA detector sites must satisfy to meet the physics goals discussed in Chapter 3. Chapter 5 is an overview of the NOvA project. The changes in the design relative to the NOvA CDR are discussed. Chapter 6 summarizes the NOvA

  13. The NOvA Technical Design Report

    International Nuclear Information System (INIS)

    Ayres, D.S.; Drake, G.R.; Goodman, M.C.; Grudzinski, J.J.; Guarino, V.J.; Talaga, R.L.; Zhao, A.; Stamoulis, P.; Stiliaris, E.; Tzanakos, G.; Zois, M.

    2007-01-01

    Technical Design Report (TDR) describes the preliminary design of the NOvA accelerator upgrades, NOvA detectors, detector halls and detector sites. Compared to the March 2006 and November 2006 NOvA Conceptual Design Reports (CDR), critical value engineering studies have been completed and the alternatives still active in the CDR have been narrowed to achieve a preliminary technical design ready for a Critical Decision 2 review. Many aspects of NOvA described this TDR are complete to a level far beyond a preliminary design. In particular, the access road to the NOvA Far Detector site in Minnesota has an advanced technical design at a level appropriate for a Critical Decision 3a review. Several components of the accelerator upgrade and new neutrino detectors also have advanced technical designs appropriate for a Critical Decision 3a review. Chapter 1 is an Executive Summary with a short description of the NOvA project. Chapter 2 describes how the Fermilab NuMI beam will provide a narrow band beam of neutrinos for NOvA. Chapter 3 gives an updated overview of the scientific basis for the NOvA experiment, focusing on the primary goal to extend the search for ν μ → ν e oscillations and measure the sin 2 (2θ 13 ) parameter. This parameter has not been measured in any previous experiment and NOvA would extend the search by about an order of magnitude beyond the current limit. A secondary goal is to measure the dominant mode oscillation parameters, sin 2 (2θ 23 ) and Δm 32 2 to a more precise level than previous experiments. Additional physics goals for NOvA are also discussed. Chapter 4 describes the Scientific Design Criteria which the Fermilab accelerator complex, NOvA detectors and NOvA detector sites must satisfy to meet the physics goals discussed in Chapter 3. Chapter 5 is an overview of the NOvA project. The changes in the design relative to the NOvA CDR are discussed. Chapter 6 summarizes the NOvA design performance relative to the Design Criteria set out

  14. Nova target experiments

    International Nuclear Information System (INIS)

    Drake, R.P.

    1985-11-01

    The Nova laser, at the Lawrence Livermore National Laboratory, provides unique opportunities for target experiments. It has unprecedented energy on target and significant flexibility. The paper presented by John Hunt described the capabilities and the status of Nova. This paper discusses plans for future experiments using Nova, and the present status of target experiments. We plan to perform high-quality physics experiments that exploit the unique capabilities of Nova. Because this is our goal, we are fielding an extensive array of well-characterized target diagnostics to measure the emissions from the target. The first section of this paper discusses the basic target diagnostics. We are also taking care to quantify the performance of the laser

  15. The role of nuclear inputs in r-process nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Giuliani, Samuel Andrea; Arzhanov, Alexander; Friess, Stephen; Martinez-Pinedo, Gabriel; Moeller, Heiko; Sieverding, Andre; Wu, Meng-Ru [TU Darmstadt (Germany)

    2016-07-01

    We have studied the sensitivity of the r-process abundances produced in dynamical ejecta from neutron star mergers to different nuclear mass models. For each mass model, the resulting abundances are almost independent of the astrophysical conditions and reproduce the general features of the observed r-process abundance. We find that the second peak around A ∝ 130 is produced by the fission yields of the material that piles up in nuclei with A >or similar 250. We also find distinct differences in the predictions at and just above the third peak (A ∝ 195) for different mass models, due to different neutron separation energies at N = 130. Due to the crucial role that fission plays in r-process nucleosynthesis, we have computed the fission properties of superheavy nuclei using the BCPM energy density functional. We found that certain combinations of neutron and proton number lead to an enhanced stability against the spontaneous fission process, related with the existence of magic numbers in the superheavy region. However, the systematic of the fission properties is strongly affected by the choice of the collective degree of freedom when the fission path is obtained by minimizing the action integral. Finally, a comparison with other theoretical models and the consequences for r-process nucleosynthesis are discussed.

  16. Challenges in nucleosynthesis of trans-iron elements

    International Nuclear Information System (INIS)

    Rauscher, T.

    2014-01-01

    Nucleosynthesis beyond Fe poses additional challenges not encountered when studying astrophysical processes involving light nuclei. Astrophysical sites and conditions are not well known for some of the processes involved. On the nuclear physics side, different approaches are required, both in theory and experiment. The main differences and most important considerations are presented for a selection of nucleosynthesis processes and reactions, specifically the s-, r-, γ-, and νp-processes. Among the discussed issues are uncertainties in sites and production conditions, the difference between laboratory and stellar rates, reaction mechanisms, important transitions, thermal population of excited states, and uncertainty estimates for stellar rates. The utility and limitations of indirect experimental approaches are also addressed. The presentation should not be viewed as confining the discussed problems to the specific processes. The intention is to generally introduce the concepts and possible pitfalls along with some examples. Similar problems may apply to further astrophysical processes involving nuclei from the Fe region upward and/or at high plasma temperatures. The framework and strategies presented here are intended to aid the conception of future experimental and theoretical approaches

  17. Neutron-capture nucleosynthesis in the first stars

    International Nuclear Information System (INIS)

    Roederer, Ian U.; Preston, George W.; Thompson, Ian B.; Shectman, Stephen A.; Sneden, Christopher

    2014-01-01

    Recent studies suggest that metal-poor stars enhanced in carbon but containing low levels of neutron-capture elements may have been among the first to incorporate the nucleosynthesis products of the first generation of stars. We have observed 16 stars with enhanced carbon or nitrogen using the MIKE Spectrograph on the Magellan Telescopes at Las Campanas Observatory and the Tull Spectrograph on the Smith Telescope at McDonald Observatory. We present radial velocities, stellar parameters, and detailed abundance patterns for these stars. Strontium, yttrium, zirconium, barium, europium, ytterbium, and other heavy elements are detected. In four stars, these heavy elements appear to have originated in some form of r-process nucleosynthesis. In one star, a partial s-process origin is possible. The origin of the heavy elements in the rest of the sample cannot be determined unambiguously. The presence of elements heavier than the iron group offers further evidence that zero-metallicity rapidly rotating massive stars and pair instability supernovae did not contribute substantial amounts of neutron-capture elements to the regions where the stars in our sample formed. If the carbon- or nitrogen-enhanced metal-poor stars with low levels of neutron-capture elements were enriched by products of zero-metallicity supernovae only, then the presence of these heavy elements indicates that at least one form of neutron-capture reaction operated in some of the first stars.

  18. Testing a Dilaton Gravity Model Using Nucleosynthesis

    International Nuclear Information System (INIS)

    Boran, S.; Kahya, E. O.

    2014-01-01

    Big bang nucleosynthesis (BBN) offers one of the most strict evidences for the Λ-CDM cosmology at present, as well as the cosmic microwave background (CMB) radiation. In this work, our main aim is to present the outcomes of our calculations related to primordial abundances of light elements, in the context of higher dimensional steady-state universe model in the dilaton gravity. Our results show that abundances of light elements (primordial D, 3 He, 4 He, T, and 7 Li) are significantly different for some cases, and a comparison is given between a particular dilaton gravity model and Λ-CDM in the light of the astrophysical observations

  19. Supernova neutrinos, giant resonances, and nucleosynthesis

    International Nuclear Information System (INIS)

    Haxton, W.

    1990-01-01

    Almost all of the 3·10 53 ergs liberated in a core collapse supernova is radiated as neutrinos by the cooling neutron star. The neutrinos can excite nuclei in the mantle of the star by their neutral and charged current reactions. I argue that the resulting spallation reactions are an important nucleosynthesis mechanism that may be responsible for the galactic abundances of 7 Li, 11 B, 19 F, 138 La, 180 Ta, and approximately a dozen other light nuclei. 18 refs., 1 fig., 1 tab

  20. Treatment of isomers in nucleosynthesis codes

    Science.gov (United States)

    Reifarth, René; Fiebiger, Stefan; Göbel, Kathrin; Heftrich, Tanja; Kausch, Tanja; Köppchen, Christoph; Kurtulgil, Deniz; Langer, Christoph; Thomas, Benedikt; Weigand, Mario

    2018-03-01

    The decay properties of long-lived excited states (isomers) can have a significant impact on the destruction channels of isotopes under stellar conditions. In sufficiently hot environments, the population of isomers can be altered via thermal excitation or de-excitation. If the corresponding lifetimes are of the same order of magnitude as the typical time scales of the environment, the isomers have to be treated explicitly. We present a general approach to the treatment of isomers in stellar nucleosynthesis codes and discuss a few illustrative examples. The corresponding code is available online at http://exp-astro.de/isomers/.

  1. Big Bang nucleosynthesis: The standard model

    International Nuclear Information System (INIS)

    Steigman, G.

    1989-01-01

    Current observational data on the abundances of deuterium, helium-3, helium-4 and lithium-7 are reviewed and these data are used to infer (or to bound) the primordial abundances of these elements. The physics of primordial nucleosynthesis in the context of the ''standard'' (isotropic, homogeneous,...) hot big bang model is outlined and the primordial abundances predicted within the context of this model are presented. The theoretical predictions are then confronted with the observational data. This confrontation reveals the remarkable consistency of the standard model, constrains the nucleon abundance to lie within a narrow range and, permits the existence of no more than one additional flavor of light neutrinos

  2. Applications for fission product data to problems in stellar nucleosynthesis

    International Nuclear Information System (INIS)

    Mathews, G.J.

    1983-10-01

    A general overview of the nucleosynthesis mechanisms for heavy (A greater than or equal to 70) nuclei is presented with particular emphasis on critical data needs. The current state of the art in nucleosynthesis models is described and areas in which fission product data may provide useful insight are proposed. 33 references, 10 figures

  3. Pulsed power supply for Nova Upgrade

    International Nuclear Information System (INIS)

    Bacon, J.L.; Kajs, J.P.; Walls, A.; Weldon, W.F.; Zowarka, R.C.

    1992-01-01

    This report describes work carried out at the Center for Electromechanics at The University of Texas at Austin (CEM-UT). A baseline design of the Nova Upgrade has been completed by Lawrence Livermore National Laboratory. The Nova Upgrade is an 18 beamline Nd: glass laser design utilizing fully relayed 4x4 30 cm aperture segmented optical components. The laser thus consists of 288 independent beamlets nominally producing 1.5 to 2.0 MJ of 0.35 μm light in a 3 to 5 ns pulse. The laser design is extremely flexible and will allow a wide range of pulses to irradiate ICF targets. This facility will demonstrate ignition/gain and the scientific feasibility of ICF for energy and defense applications. The pulsed power requirements for the Nova Upgrade are given. CEM-UT was contracted to study and develop a design for a homopolar generator/inductor (HPG/inductor) opening switch system which would satisfy the pulsed power supply requirements of the Nova Upgrade. The Nd:glass laser amplifiers used in the Nova Upgrade will be powered by light from xenon flashlamps. The pulsed power supply for the Nova Upgrade powers the xenon flashlamps. This design and study was for a power supply to drive flashlamps

  4. A nova outburst powered by shocks

    Science.gov (United States)

    Li, Kwan-Lok; Metzger, Brian D.; Chomiuk, Laura; Vurm, Indrek; Strader, Jay; Finzell, Thomas; Beloborodov, Andrei M.; Nelson, Thomas; Shappee, Benjamin J.; Kochanek, Christopher S.; Prieto, José L.; Kafka, Stella; Holoien, Thomas W.-S.; Thompson, Todd A.; Luckas, Paul J.; Itoh, Hiroshi

    2017-10-01

    Classical novae are runaway thermonuclear burning events on the surfaces of accreting white dwarfs in close binary star systems, sometimes appearing as new naked-eye sources in the night sky1. The standard model of novae predicts that their optical luminosity derives from energy released near the hot white dwarf, which is reprocessed through the ejected material2-5. Recent studies using the Fermi Large Area Telescope have shown that many classical novae are accompanied by gigaelectronvolt γ-ray emission6,7. This emission likely originates from strong shocks, providing new insights into the properties of nova outflows and allowing them to be used as laboratories for the study of the unknown efficiency of particle acceleration in shocks. Here, we report γ-ray and optical observations of the Milky Way nova ASASSN-16ma, which is among the brightest novae ever detected in γ-rays. The γ-ray and optical light curves show a remarkable correlation, implying that the majority of the optical light comes from reprocessed emission from shocks rather than the white dwarf8. The ratio of γ-ray to optical flux in ASASSN-16ma directly constrains the acceleration efficiency of non-thermal particles to be around 0.005, favouring hadronic models for the γ-ray emission9. The need to accelerate particles up to energies exceeding 100 gigaelectronvolts provides compelling evidence for magnetic field amplification in the shocks.

  5. Deep seismic studies of conjugate profiles from the Nova Scotia - Moroccan and the Liguro-Provencal margin pairs

    Science.gov (United States)

    Klingelhoefer, F.; Biari, Y.; Sahabi, M.; Aslanian, D.; Philippe, S.; Schnabel, M.; Moulin, M.; Louden, K. E.; Funck, T.; Reichert, C. J.

    2014-12-01

    The structure of conjugate passive margins provides information about rifting styles, opening of an ocean and formation of it's associated sedimentary basins. In order to distinguish between tectonic inheritance and structures directly related to rifting of passive margins conjugate profiles have to be acquired on margins on diverse locations and different ages. In this study we use new and existing reflection and wide-angle seismic data from two margin pairs, the 200 Ma year old Nova-Scotia - Morocco margin pair and the only 20 Ma Gulf of Lions - Sardinia margin pair. On both margin pairs wide-angle seismic data combined with reflection seismic data were acquired on conjugate profiles on sea and extended on land. Forward modelling of the deep crustal structure along the four transects indicates that a high velocity zone (HVZ) (> 7.2 km/s) is present at the base of the lower crust on all four margins along the ocean-continental transition zone (OCT). This may represent either exhumed upper mantle material or injection of upper mantle material into proto-oceanic crust at the onset of sea-floor spreading. However the width of the HVZ might strongly differ between conjugates, which may be the result of tectonic inheritance, for example the presence of ancient subduction zones or orogens. Both margin pairs show a similar unthinned continental crustal thickness. Crustal thinning and upper-to-lower crustal thickness vary between margin pairs, but remain nearly symmetric on conjugate profiles and might therefore depend on the structure and mechanical properties of the original continental crust. For the Mediterranean margin pair, the oceanic crust is similar on both sides, with a thickness of only 4-5 km. For the Atlantic margin pair, oceanic crustal thickness is higher on the Moroccan Margin, a fact that can be explained by either asymmetric spreading or by the volcanic underplating, possibly originating from the Canary Hot Spot.

  6. Nova Aql 1918: A nude old nova

    International Nuclear Information System (INIS)

    Selvelli, P.L.; Cassatella, A.

    1981-01-01

    IUE observations at high and low resolution of Nova Aql 1918 show neither evidence of outflow nor the presence of nebular lines. This indicates that the shell ejected at the time of the outburst and surrounding the system for many years (Mustel and Boyarchuck, 1970) has by now disappeared. The high excitation spectrum presents rapid variations in the far UV and eclipse effects in the near UV that seem well correlated with the orbital phase. The observations can be interpreted in terms of phenomena occurring in or near the accretion disk surrounding the white dwarf. However, the small inclination of the orbital axis raises serious problems in trying to model the system. (Auth.)

  7. Neutrino nucleosynthesis in core-collapse Supernova explosions

    Directory of Open Access Journals (Sweden)

    Sieverding A.

    2016-01-01

    Full Text Available The neutrino-induced nucleosynthesis (ν process in supernova explosions of massive stars of solar metallicity with initial main sequence masses between 15 and 40 M⊙ has been studied. A new extensive set of neutrino-nucleus cross-sections for all the nuclei included in the reaction network is used and the average neutrino energies are reduced to agree with modern supernova simulations. Despite these changes the ν process is found to contribute still significantly to the production of the nuclei 7Li, 11B, 19F, 138La and 180Ta, even though the total yields for those nuclei are reduced. Furthermore we study in detail contributions of the ν process to the production of radioactive isotopes 26Al, 22Na and confirm the production of 92Nb and 98Tc.

  8. Neutrino nucleosynthesis in core-collapse Supernova explosions

    Science.gov (United States)

    Sieverding, A.; Huther, L.; Martínez-Pinedo, G.; Langanke, K.; Heger, A.

    2018-01-01

    The neutrino-induced nucleosynthesis (v process) in supernova explosions of massive stars of solar metallicity with initial main sequence masses between 15 and 40 M⨀ has been studied. A new extensive set of neutrino-nucleus cross-sections for all the nuclei included in the reaction network is used and the average neutrino energies are reduced to agree with modern supernova simulations. Despite these changes the v process is found to contribute still significantly to the production of the nuclei 7Li, 11B, 19F, 138La and 180Ta, even though the total yields for those nuclei are reduced. Furthermore we study in detail contributions of the v process to the production of radioactive isotopes 26Al, 22Na and confirm the production of 92Nb and 98Tc.

  9. School Psychology in Nova Scotia

    Science.gov (United States)

    King, Sara; McGonnell, Melissa; Noyes, Amira

    2016-01-01

    Registration as a psychologist in Nova Scotia can be at the master's or doctoral level; however, the Nova Scotia Board of Examiners in Psychology has announced a move to the doctoral degree as the entry-level to practice. Many school psychologists in Nova Scotia practice at the master's level; therefore, this change could affect school psychology…

  10. Dark/visible parallel universes and Big Bang nucleosynthesis

    International Nuclear Information System (INIS)

    Bertulani, C. A.; Frederico, T.; Fuqua, J.; Hussein, M. S.; Oliveira, O.; Paula, W. de

    2012-01-01

    We develop a model for visible matter-dark matter interaction based on the exchange of a massive gray boson called herein the Mulato. Our model hinges on the assumption that all known particles in the visible matter have their counterparts in the dark matter. We postulate six families of particles five of which are dark. This leads to the unavoidable postulation of six parallel worlds, the visible one and five invisible worlds. A close study of big bang nucleosynthesis (BBN), baryon asymmetries, cosmic microwave background (CMB) bounds, galaxy dynamics, together with the Standard Model assumptions, help us to set a limit on the mass and width of the new gauge boson. Modification of the statistics underlying the kinetic energy distribution of particles during the BBN is also discussed. The changes in reaction rates during the BBN due to a departure from the Debye-Hueckel electron screening model is also investigated.

  11. Massive stars with mass loss: Evolution, nucleosynthesis, and astrophysical implications

    International Nuclear Information System (INIS)

    Prantzos, N.

    1986-06-01

    Evolution and nucleosynthesis of mass loss WR stars is studied, particularly evolution of stars with initial mass between 50 and 100 solar masses, during combustion of H and He. A semi-empirical mass loss formalism, the Roxburgh criterion for convection, and nuclear data are used. Composition of the stellar surface and ejecta (and ejecta contribution to cosmic ray composition) are derived. The contribution of these stars to s elements in our solar system is shown. Their production of 26 Al is compared to the quantity in the galaxy. Gamma ray emission at 1.8 MeV from the decay of this radionuclide is estimated in galactic longitude. The stars evolve as 0 and 0f stars during H combustion and spend 20% of their He combustion period as WN stars and 80% as WC-W0. Evolution always occurs in the blue part of the HR diagram, and satisfies observational constraints on its upper part [fr

  12. Gravitino, dark matter candidate and implications for big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Bailly, S.

    2008-11-01

    The Standard Model of particle physics was developed in the seventies. Despite many experimental successes, it presents many problems that can only be solved with models beyond the Standard Model. Supersymmetry is an interesting candidate, postulating a new symmetry between fermions and bosons. This model can also have interesting applications in cosmology. It offers potentially good candidates for dark matter, what represents 25% of the energy density of the Universe, and its nature is unknown. Another cosmological problem is the lithium problems in Big Bang Nucleosynthesis describing the production of light elements in the first seconds of the Universe. The lithium abundance predicted by the theory is inconsistent with observations. I study a scenario in which a supersymmetric particle, the gravitino, is the candidate for dark matter and the production of this particle through the decay of other supersymmetric particles may solve the lithium problems. (author)

  13. Quark mass variation constraints from Big Bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Bedaque, P; Luu, T; Platter, L

    2010-12-13

    We study the impact on the primordial abundances of light elements created of a variation of the quark masses at the time of Big Bang nucleosynthesis (BBN). In order to navigate through the particle and nuclear physics required to connect quark masses to binding energies and reaction rates in a model-independent way we use lattice QCD data and an hierarchy of effective field theories. We find that the measured {sup 4}He abundances put a bound of {delta}-1% {approx}< m{sub q}/m{sub 1} {approx}< 0.7%. The effect of quark mass variations on the deuterium abundances can be largely compensated by changes of the baryon-to-photon ratio {eta}. Including the bounds on the variation of {eta} coming from WMAP results and some additional assumptions narrows the range of allowed values of {delta}m{sub q}/m{sub q} somewhat.

  14. New Novae snack point

    CERN Document Server

    2012-01-01

    Located next to the car park by the flag poles, a few metres from the Main CERN Reception (building 33), a new snack point catered by Novae will open to the public on Wednesday 8 August. More information will be available in the next issue of the Bulletin!

  15. Aprendizagens e novas tecnologias

    Directory of Open Access Journals (Sweden)

    Pedro Demo

    2011-06-01

    Full Text Available Pretendo aqui, muito preliminarmente, reunir alguns argumentos favoráveis à multiplicidade de oportunidades de aprender que o aluno pode encontrar hoje em ambientes de aprendizagem mediados por novas tecnologias. Centro-me principalmente na desconstrução de algumas resistências pedagógicas (EVANS, 2001 ainda persistentes entre nós como “transmissão de conteúdos”; agarramento a uma única teoria; fixação na aula instrucionista; extirpação/endeusamento de processos avaliativos, etc. Procuro ver, em um vasto âmbito de ofertas teóricas, componentes atualmente ressaltados na discussão tecnológica em vigor, com o objetivo de indicar oportunidades de reconstrução muito aproveitável de autores e clássicos, uma vez que aprender bem não foi algo inventado pelas novas tecnologias; sempre existiu e os grandes pedagogos tiveram consciência disso, insinuando infinitas maneiras de aprender bem (DEMO, 2008. As novas tecnologias proporcionam oportunidades ainda mais ampliadas, em meio também a enormes riscos e desacertos. O que menos interessa aqui é incidir em panaceias tecnológicas, bem a gosto do consumismo neoliberal. Interessa, porém, explorar novas oportunidades de aprendizagem, bem mais centradas na atividade dos alunos, flexíveis, motivadoras e capazes de sustentar processos de autoria e autonomia.

  16. Neutrino nucleosynthesis in supernovae: Shell model predictions

    International Nuclear Information System (INIS)

    Haxton, W.C.

    1989-01-01

    Almost all of the 3 · 10 53 ergs liberated in a core collapse supernova is radiated as neutrinos by the cooling neutron star. I will argue that these neutrinos interact with nuclei in the ejected shells of the supernovae to produce new elements. It appears that this nucleosynthesis mechanism is responsible for the galactic abundances of 7 Li, 11 B, 19 F, 138 La, and 180 Ta, and contributes significantly to the abundances of about 15 other light nuclei. I discuss shell model predictions for the charged and neutral current allowed and first-forbidden responses of the parent nuclei, as well as the spallation processes that produce the new elements. 18 refs., 1 fig., 1 tab

  17. Big-Bang nucleosynthesis and lithium abundance

    International Nuclear Information System (INIS)

    Singh, Vinay; Lahiri, Joydev; Bhowmick, Debasis; Basu, D.N.

    2017-01-01

    The predictions of the standard big-bang nucleosynthesis (BBN) theory depend on the astrophysical nuclear reaction rates and on additional three parameters, the number of flavours of light neutrinos, the neutron lifetime and the baryon-to-photon ratio in the uni- verse. The effect of the modification of thirty-five reaction rates on light element abundance yields in BBN was investigated earlier by us. In the present work we have replaced the neutron lifetime, baryon-to-photon ratio by the most recent values and further modified 3 He( 4 He,γ) 7 Be reaction rate which is used directly for estimating the formation of 7 Li as a result of β + decay by the most recent equation. We find that these modifications reduce the calculated abundance of 7 Li by ∼ 12%

  18. Primordial nucleosynthesis in the new cosmology

    International Nuclear Information System (INIS)

    Cyburt, R.H.

    2003-01-01

    Big bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies independently predict the universal baryon density. Comparing their predictions will provide a fundamental test on cosmology. Using BBN and the CMB together, we will be able to constrain particle physics, and predict the primordial, light element abundances. These future analyses hinge on new experimental and observational data. New experimental data on nuclear cross sections will help reduce theoretical uncertainties in BBN's predictions. New observations of light element abundances will further sharpen BBN's probe of the baryon density. Observations from the MAP and PLANCK satellites will measure the fluctuations in the CMB to unprecedented accuracy, allowing the precise determination of the baryon density. When combined, this data will present us with the opportunity to perform precision cosmology

  19. Neutron-capture Nucleosynthesis in the First Stars

    Science.gov (United States)

    Roederer, Ian U.; Preston, George W.; Thompson, Ian B.; Shectman, Stephen A.; Sneden, Christopher

    2014-04-01

    Recent studies suggest that metal-poor stars enhanced in carbon but containing low levels of neutron-capture elements may have been among the first to incorporate the nucleosynthesis products of the first generation of stars. We have observed 16 stars with enhanced carbon or nitrogen using the MIKE Spectrograph on the Magellan Telescopes at Las Campanas Observatory and the Tull Spectrograph on the Smith Telescope at McDonald Observatory. We present radial velocities, stellar parameters, and detailed abundance patterns for these stars. Strontium, yttrium, zirconium, barium, europium, ytterbium, and other heavy elements are detected. In four stars, these heavy elements appear to have originated in some form of r-process nucleosynthesis. In one star, a partial s-process origin is possible. The origin of the heavy elements in the rest of the sample cannot be determined unambiguously. The presence of elements heavier than the iron group offers further evidence that zero-metallicity rapidly rotating massive stars and pair instability supernovae did not contribute substantial amounts of neutron-capture elements to the regions where the stars in our sample formed. If the carbon- or nitrogen-enhanced metal-poor stars with low levels of neutron-capture elements were enriched by products of zero-metallicity supernovae only, then the presence of these heavy elements indicates that at least one form of neutron-capture reaction operated in some of the first stars. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile, and The McDonald Observatory of The University of Texas at Austin.

  20. Measurement of resonances of interest in "1"9Ne for novae study via a new method of inelastic scattering

    International Nuclear Information System (INIS)

    Boulay, Florent

    2015-01-01

    A nova is a thermonuclear runaway occurring in binary system of stars. The observation of the gamma rays emitted after a nova is a way to better understand this phenomenon. According to the models, the line at 511 keV, produced in the annihilation between positrons and electrons, would be the most intense line several hours after the explosion. One of the main positron emitters would be the "1"8F radioactive isotope. In order to improve the predictive power of the models, it is crucial to better determine the amount of "1"8F produced in the nova. Yet, the "1"8F destruction rate "1"8F(p,α)"1"5O is given with large uncertainties. Measuring the spectroscopic properties (energy, width, spin) of states in the compound nucleus "1"9Ne should allow us to constrain the reaction rate. In this context, an experiment based on a new inelastic scattering method ("1"9Ne(p,p')"1"9Ne"*) was performed at GANIL with the VAMOS spectrometer. The detection system has been adapted to detect for the first time high energy protons (p'). A good energy resolution in inverse kinematic has been reached (σ=33 keV). The angular distribution measurement of decaying particles should provide the spin assignment of the states in a model independent way. Unfortunately, an unforeseen contamination has prevented us to complete this measurement. New spectroscopic information have been extracted and contributed to reduce the uncertainty of the "1"8F(p,α)"1"5O reaction rate in a significant way. The data are compatible with a new broad state below the proton threshold (6.41 MeV). This state seems to be sufficiently broad to contribute to the destruction reaction rate of "1"8F and reduces the chances for satellite detection. (author) [fr

  1. Study of 17O(p,α)14N reaction via the Trojan Horse Method for application to 17O nucleosynthesis

    International Nuclear Information System (INIS)

    Sergi, M. L.; Spitaleri, C.; Pizzone, R. G.; Gulino, M.; Cherubini, S.; Crucilla, V.; La Cognata, M.; Lamia, L.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Tudisco, S.; Tumino, A.; Coc, A.; Burjan, V.; Hons, Z.; Kroha, V.; Hammache, F.; Sereville, N. de; Kiss, G.

    2008-01-01

    Because of the still present uncertainties on its rate, the 17 O(p,α) 14 N is one of the most important reaction to be studied in order to get more information about the fate of 17 O in different astrophysical scenarios. The preliminary study of the three-body reaction 2 H( 17 O,α 14 N)n is presented here as a first stage of the indirect study of this important 17 O(p,α) 14 N reaction through the Trojan Horse Method (THM)

  2. Precision mass measurements for studies of nucleosynthesis via the rapid neutron-capture process. Penning-trap mass measurements of neutron-rich cadmium and caesium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Atanasov, Dinko

    2016-07-06

    Although the theory for the rapid neutron-capture process (r-process) was developed more than 55 years ago, the astrophysical site is still under a debate. Theoretical studies predict that the r-process path proceeds through very neutron-rich nuclei with very asymmetric proton-to-neutron ratios. Knowledge about the properties of neutron-rich isotopes found in similar regions of the nuclear chart and furthermore suitable for r-process studies is still little or even not existing. The basic nuclear properties such as binding energies, half-lives, neutron-induced or neutron-capture reaction cross-sections, play an important role in theoretical simulations and can vary or even drastically alternate results of these studies. Therefore, a considerable effort was put forward to access neutron-rich isotopes at radioactive ion-beam facilities like ISOLDE at CERN. The goal of this PhD thesis is to describe the experimental work done for the precision mass measurements of neutron-rich cadmium ({sup 129-131}Cd) and caesium ({sup 132,146-148}Cs) isotopes. Measurements were done at the on-line radioactive ion-beam facility ISOLDE by using the four-trap mass spectrometer ISOLTRAP. The cadmium isotopes are key nuclides for the synthesis of stable isotopes around the mass peak A = 130 in the Solar System abundance.

  3. Precision mass measurements for studies of nucleosynthesis via the rapid neutron-capture process Penning-trap mass measurements of neutron-rich cadmium and caesium isotopes

    CERN Document Server

    AUTHOR|(CDS)2085660; Litvinov, Yuri A.; Kreim, Susanne

    Although the theory for the rapid neutron-capture process (r-process) was developed more than 55 years ago, the astrophysical site is still under a debate. Theoretical studies predict that the r-process path proceeds through very neutron-rich nuclei with very asymmetric proton- to-neutron ratios. Knowledge about the properties of neutron-rich isotopes found in similar regions of the nuclear chart and furthermore suitable for r-process studies is still little or even not existing. The basic nuclear properties such as binding energies, half-lives, neutron-induced or neutron-capture reaction cross-sections, play an important role in theoretical simulations and can vary or even drastically alternate results of these studies. Therefore, a considerable effort was put forward to access neutron-rich isotopes at radioactive ion-beam facilities like ISOLDE at CERN. The goal of this PhD thesis is to describe the experimental work done for the precision mass measurements of neutron-rich cadmium (129−131 Cd) and caesium...

  4. Imaging the Ejecta in Classical Novae

    Science.gov (United States)

    Linford, Justin

    2016-10-01

    A nova outburst results when sufficient mass accretes from a companion star onto the surface of a white dwarf, triggering a thermonuclear explosion. In classical novae the bulk of the emission comes from the warm, expanding ejecta. The prevailing theories assume that the explosion occurs as a single, spherically symmetric ejection event and predict a simple relationship between the white dwarf mass, the accretion rate, and the mass loss and energetics of the explosion. However, observations with modern instruments indicate that nova eruptions are far from simple. There is now evidence for multiple ejection events, common envelopes, non-spherical geometry, and even jet-like structures in the ejecta. Our ENova collaboration combines radio, mm, optical, and X-ray observations and detailed theoretical modelling to study the most common major explosions in the universe. Among our results so far are the direct demonstration of the importance of shocks in novae, including the detection of gamma-ray producing shocks in several sources, and the realization that multiple, long-lived outflows are much more common than previously assumed. Here we propose to continue these highly successful observations with coordinated detailed VLA radio interferometry and HST optical imaging and spectroscropy of several recent novae with substantial VLA monitoring already in progress.

  5. X-ray Modeling of Classical Novae

    Science.gov (United States)

    Nemeth, Peter

    2010-01-01

    It has been observed and theoretically supported in the last decade that the peak of the spectral energy distribution of classical novae gradually shifts to higher energies at constant bolometric luminosity after a nova event. For this reason, comprehensive evolutionary studies require spectral analysis in multiple spectral bands. After a nova explosion, the white dwarf can maintain stable surface hydrogen burning, the duration of which strongly correlates with the white dwarf mass. During this stage the peak of the luminosity is in the soft X-ray band (15 - 60 Angstroms). By extending the modeling range of TLUSTY/SYNSPEC, I analyse the luminosity and abundance evolution of classical novae. Model atoms required for this work were built using atomic data from NIST/ASD and TOPBASE. The accurate but incomplete set of energy levels and radiative transitions in NIST were completed with calculated data from TOPBASE. Synthetic spectra were then compared to observed data to derive stellar parameters. I show the capabilities and validity of this project on the example of V4743 Sgr. This nova was observed with both Chandra and XMM-Newton observatories and has already been modeled by several scientific groups (PHOENIX, TMAP).

  6. Dynamic testing of NOVA laser switchyard tower

    International Nuclear Information System (INIS)

    Weaver, H.J.; Pastrnak, J.W.; Fields, D.E.

    1984-01-01

    NOVA is the latest in a series of powerful laser systems designed to study the feasibility of initiating a controlled fusion reaction by concentrating several laser beams on a small fuel target. The laser components, turning mirrors and target chamber are all mounted on large steel frame structures. These structures were first analyzed via finite element models to access their seismic integrity as well as their overall vibrational stability. When construction was completed, a modal analysis was performed on the structures to verify and improve the finite element models. This report discusses the linking of the analytical and experimental studies for the NOVA switchyard tower structure

  7. A Knowledge Transfer Study of the Utility of the Nova Scotia Seniors’ Mental Health Network in Implementing Seniors’ Mental Health National Guidelines

    Science.gov (United States)

    Bosma, Mark; Cassidy, Keri-Leigh; Le Clair, J Kenneth; Helsdingen, Sherri; Devichand, Pratima

    2011-01-01

    Background The Canadian Coalition for Seniors’ Mental Health (CCSMH) developed national best-practice guidelines in seniors’ mental health. Promoting adoption of new guidelines is challenging, as paper dissemination alone has limited impact on practice change. Purpose We hypothesized that the existing knowledge transfer (KT) mechanisms of the Nova Scotia Seniors’ Mental Health Network would prove useful in transferring the CCSMH best-practice guidelines. Methods In this observational KT study, CCSMH best-practice guidelines were delivered through two interactive, case-based teaching modules on Depression & Suicide, and Delirium via a provincial tele-education program and local face-to-face sessions. Usefulness of KT was measured using self-report evaluations of material quality and learning. Evaluation results from the two session topics and from tele-education versus face-to-face sessions were compared. Results Sessions were well attended (N = 347), with a high evaluation return rate (287, 83%). Most participants reported enhanced knowledge in seniors’ mental health and intended to apply knowledge to practice. Ratings did not differ significantly between KT session topics or modes of delivery. Conclusions The KT mechanisms of a provincial seniors’ mental health network facilitated knowledge acquisition and the intention of using national guidelines on seniors’ mental health among Nova Scotian clinicians. Key elements of accelerating KT used in this initiative are discussed. PMID:23251305

  8. The distances of the Galactic Novae

    Science.gov (United States)

    Ozdonmez, Aykut; Guver, Tolga; Cabrera-Lavers, Antonio; Ak, Tansel

    2016-07-01

    Using location of the RC stars on the CMDs obtained from the UKIDSS, VISTA and 2MASS photometry, we have derived the reddening-distance relations towards each Galactic nova for which at least one independent reddening measurement exists. We were able to determine the distances of 72 Galactic novae and set lower limits on the distances of 45 systems. The reddening curves of the systems are presented. These curves can be also used to estimate reddening or the distance of any source, whose location is close to the position of the nova in our sample. The distance measurement method in our study can be easily applicable to any source, especially for ones that concentrated along the Galactic plane.

  9. Long-term cycles in old Novae

    International Nuclear Information System (INIS)

    Shara, M.M.; Potter, M.; Shara, D.J.

    1989-01-01

    Three of the oldest recovered novae were monitored with a CCD camera almost nightly for six weeks. The cyclic variability reported by Della Valle and Rosino (1987) for Nova Oph 1848 is confirmed. A similar variability is also suggested for Nova Cyg 1876, though this system exhibits more random flickering than Nova Oph. No secular variability is seen in Nova Sge 1783. 12 refs

  10. Power relations perceptions in a Brazilian favela: a case study of Vila Nova Esperança inhabitants association directors

    OpenAIRE

    Colombas, Simón Marti

    2014-01-01

    Vila Nova Esperança é uma das 400 favelas do estado de São Paulo. Nos últimos anos, esta comunidade sobreviveu a um duro processo judiciário em contra de poderosos órgãos governamentais e ganhou a atenção de organizações não governamentais que vêm esta comunidade como um lugar de sucesso para implementar os seus projetos. O objetivo desta dissertação é analisar quem som os atores de dentro e de fora que mais influencia têm na comunidade, como foi que eles conseguiram esse poder e as implicaçõ...

  11. Nova Upgrade program: ignition and beyond

    International Nuclear Information System (INIS)

    Storm, E.; Campbell, E.M.; Hogan, W.J.; Lindl, J.D.

    1993-01-01

    The Lawrence Livermore National Laboratory (LLNL) Inertial Confinement Fusion (ICF) Program is addressing the critical physics and technology issues directed toward demonstrating and exploiting ignition and propagating burn to high gain with ICF targets for both defense and civilian applications. Nova is the primary U.S. facility employed in the study of the X-ray-driven (indirect drive) approach to ICF. Nova's principal objective is to demonstrate that laser-driven hohlraums can achieve the conditions of driver-target coupling efficiency, driver irradiation symmetry, driver pulseshaping, target preheat, and hydrodynamic stability required by hot-spot ignition and fuel compression to realize a fusion gain. (author)

  12. Discrepancies between knowledge and practice of childhood motor vehicle occupant safety in Nova Scotia--a population-based study.

    Science.gov (United States)

    Yanchar, Natalie L; Kirkland, Susan A; LeBlanc, John C; Langille, Donald B

    2012-03-01

    To determine discrepancies between knowledge and practice of childhood motor vehicle restraints (CMVRs) and vehicle seating position amongst parents within the province of Nova Scotia. Random telephone survey. The Canadian province of Nova Scotia. Four hundred and twenty-six households with at least one child under the age of 12 years, totaling 723 children. The proportion of parents whose children who should be in a specific stage of CMVR and sitting in the rear seat of the vehicle, and who demonstrate correct knowledge of that restraint system and seating position, yet do not use that restraint system/seating position for their child (demonstrate practice discrepant from their knowledge). Awareness of what restraint system to use is good (>80%). However, knowledge of when it is safe to graduate to the next stage is low (30-55%), most marked for when to use a seatbelt alone. Awareness of the importance of sitting in the rear seat of a vehicle was universal. Discrepancies between knowledge and practice were most marked with booster seats and rear-seating of older children. Factors influencing incorrect practice (prematurely graduated to a higher-level restraint system than what is appropriate for age and weight) included lower household income, caregiver education level, and knowledge of when to graduate from forward-facing car seats and booster seats. Incorrect practice was also more commonly observed amongst children of weight and/or age approaching (but not yet reaching) recommended graduation parameters of the appropriate CMVR. Discrepancies between knowledge and practice are evident through all stages of CMVRs, but most marked with booster seats. The roles of lower socioeconomic status and gaps in CMVR legislation, in influencing discrepant practice, must be acknowledged and suggest the need for targeted education concurrent with development of comprehensive all-stages CMVR policies. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Big Bang Nucleosynthesis: Impact of Nuclear Physics Uncertainties on Baryonic Matter Density

    International Nuclear Information System (INIS)

    Smith, Michael Scott; Roberts, Luke F.; Hix, William Raphael; Bruner, Blake D.; Kozub, R.L.; Tytler, David; Fuller, George M.; Lingerfelt, Eric J.; Nesaraja, Caroline D

    2008-01-01

    We performed new Big Bang Nucleosynthesis simulations with the bigbangonline.org suite of codes to determine, from the nuclear physics perspective, the highest achievable precision of the constraint on the baryon-to-photo ratio η given current observational uncertainties. We also performed sensitivity studies to determine the impact that particular nuclear physics measurements would have on the uncertainties of predicted abundances and on the η constraint.

  14. Big Bang Nucleosynthesis: Impact of Nuclear Physics Uncertainties on Baryonic Matter Density Constraints

    International Nuclear Information System (INIS)

    Smith, Michael S.; Roberts, Luke F.; Hix, W. Raphael; Bruner, Blake D.; Kozub, Raymond L.; Tytler, David; Fuller, George M.; Lingerfelt, Eric; Nesaraja, Caroline D.

    2008-01-01

    We performed new Big Bang Nucleosynthesis simulations with the bigbangonline.org suite of codes to determine, from the nuclear physics perspective, the highest achievable precision of the constraint on the baryon-to-photo ratio η given current observational uncertainties. We also performed sensitivity studies to determine the impact that particular nuclear physics measurements would have on the uncertainties of predicted abundances and on the η constraint

  15. Big Bang Nucleosynthesis: Impact of Nuclear Physics Uncertainties on Baryonic Matter Density Constraints

    International Nuclear Information System (INIS)

    Smith, Michael Scott; Bruner, Blake D; KOZUB, RAYMOND L.; Roberts, Luke F.; Tytler, David; Fuller, George M.; Lingerfelt, Eric; Hix, William Raphael; Nesaraja, Caroline D

    2008-01-01

    We ran new Big Bang Nucleosynthesis simulations with the bigbangonline.org suite of codes to determine, from the nuclear physics perspective, the highest achievable precision of the constraint on the baryon-to-photo ratio eta given current observational uncertainties. We also ran sensitivity studies to determine the impact that particular nuclear physics measurements would have on the uncertainties of predicted abundances and on the eta constraint

  16. Big-bang nucleosynthesis - observational aspects

    International Nuclear Information System (INIS)

    Pagel, B.E.J.

    1990-01-01

    Extrapolation of observational data on the abundances of D, 3 He, 4 He and 7 Li in various astrophysical objects to derive their primordial values leads to results in good accordance with calculations from Standard Big Bang nucleosynthesis theory over 9 orders of magnitude in abundance and has led to the following predictions: There are not more than 3 light neutrino species or other particles contributing relativistic degrees of freedom at temperatures of a few MeV; the neutron half-life is less than 10.4 minutes; and baryonic dark matter exists, but not in sufficient quantities to close the universe. (The first two of these predictions have been confirmed by laboratory experiments). Searches for a primordial component in the abundance of any other element heavier than hydrogen - such as might have resulted from inhomogeneities due to phase transitions in the early universe, notably the quark-hadron transition - have so far proved completely negative. The primordial helium abundance is found from observations of extragalactic ionized hydrogen clouds to be close to 0.230 by mass, a little lower than predicted, but the difference does not exceed likely errors. (orig.)

  17. Spallation nucleosynthesis by accelerated charged-particles

    International Nuclear Information System (INIS)

    Goriely, S.

    2008-01-01

    Recent observations have suggested the presence of radioactive elements, such as Pm and 84≤Z≤99 elements) at the surface of the magnetic star HD101065, also known as Przybylski's star. This star is know to be a chemically peculiar star and its anomalous 38 30 heavy elements can be achieved. In this nucleosynthesis process, the secondary-neutron captures play a crucial role. The most attractive feature of the spallation process is the systematic production of Pm and Tc and the possible synthesis of actinides and sub-actinides.Based on such a parametric model, it is also shown that intense fluences of accelerated charged-particles interacting with surrounding material can efficiently produce elements heavier than iron. Different regimes are investigated and shown to be at the origin of p- and s-nuclei in the case of high-fluence low-flux events and r-nuclei for high-fluence high-flux irradiations. The possible existence of such irradiation events need to be confirmed by hydrodynamics simulations, but most of all by spectroscopic observations through the detection of short-lived radio-elements

  18. Summary of Recent Developments in Primordial Nucleosynthesis.

    Science.gov (United States)

    Schramm, D N

    1993-06-01

    This paper summarizes the recent observational and theoretical results on Big Bang Nucleosynthesis. In particular, it is shown that the new Pop II (6)Li results strongly support the argument that the Spite Plateau lithium is a good estimate of the primordial value. The (6)Li is consistent with the Be and Be found in Pop II stars, assuming those elements are cosmic ray produced. The HST (2)D value tightens the (2)D arguments and the observation of the (3)He in planetary nebula strengthens the (3)He +(2)D argument as a lower bound on Ωb. The new low metalicity (4)He determinations slightly raise the best primordial (4)He number and thus make a better fit and avoid a potential problem. The quark-hadron inspired inhomogeneous calculations now unanimously agree that only relatively small variations in Ωb are possible vis-à-vis the homogeneous model; hence, the robustness of Ωb∼ 0.05 is now apparent. A comparison with the ROSAT cluster data is also shown to be consistent with the standard BBN model. Ωb∼ 1 seems to be definitely excluded, so, if Ω= 1, as some recent observations may hint, then non-baryonic dark matter is required.

  19. Inhomogeneous neutrino degeneracy and big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Whitmire, Scott E.; Scherrer, Robert J.

    2000-01-01

    We examine big bang nucleosynthesis (BBN) in the case of inhomogeneous neutrino degeneracy, in the limit where the fluctuations are sufficiently small on large length scales that the present-day element abundances are homogeneous. We consider two representative cases: degeneracy of the electron neutrino alone and equal chemical potentials for all three neutrinos. We use a linear programming method to constrain an arbitrary distribution of the chemical potentials. For the current set of (highly restrictive) limits on the primordial element abundances, homogeneous neutrino degeneracy barely changes the allowed range of the baryon-to-photon ratio η. Inhomogeneous degeneracy allows for little change in the lower bound on η, but the upper bound in this case can be as large as η=1.1x10 -8 (only ν e degeneracy) or η=1.0x10 -9 (equal degeneracies for all three neutrinos). For the case of inhomogeneous neutrino degeneracy, we show that there is no BBN upper bound on the neutrino energy density, which is bounded in this case only by limits from structure formation and the cosmic microwave background. (c) 2000 The American Physical Society

  20. The Main Path to C, N, O Elements in Big Bang Nucleosynthesis

    International Nuclear Information System (INIS)

    Su-Qing, Hou; Kai-Su, Wu; Yong-Shou, Chen; Neng-Chuan, Shu; Zhi-Hong, Li

    2010-01-01

    The production of C, N, O elements in a standard big bang nucleosynthesis scenario is investigated. Using the up-to-date data of nuclear reactions in BBN, in particular the 8 Li (n,γ) 9 Li which has been measured in China Institute of Atomic Energy, a full nucleosynthesis network calculation of BBN is carried out. Our calculation results show that the abundance of 12 C is increased for an order of magnitude after addition of the reaction chain 8 Li(n,γ) 9 Li(α,n) 12 B(β) 12 C, which was neglected in previous studies. We find that this sequence provides the main channel to convert the light elements into C, N, O in standard BBN. (nuclear physics)

  1. Direct nuclear reaction experiments for stellar nucleosynthesis

    International Nuclear Information System (INIS)

    Cherubini, S.

    2016-01-01

    During the last two decades indirect methods where proposed and used in many experiments in order to measure nuclear cross sections between charged particles at stellar energies. These are among the lowest to be measured in nuclear physics. One of these methods, the Trojan Horse method, is based on the Quasi- Free reaction mechanism and has proved to be particularly flexible and reliable. It allowed for the measurement of the cross sections of various reactions of astrophysical interest using stable beams. The use and reliability of indirect methods become even more important when reactions induced by Radioactive Ion Beams are considered, given the much lower intensity generally available for these beams. The first Trojan Horse measurement of a process involving the use of a Radioactive Ion Beam dealt with the "1"8F(p,α)"1"5O process in Nova conditions. To obtain pieces of information on this process, in particular about its cross section at Nova energies, the Trojan Horse method was applied to the "1"8F(d,α "1"5O)n three body reaction. In order to establish the reliability of the Trojan Horse method approach, the Treiman-Yang criterion is an important test and it will be addressed briefly in this paper.

  2. Effects of neutrino oscillations on nucleosynthesis and neutrino signals for an 18 M⊙ supernova model

    Science.gov (United States)

    Wu, Meng-Ru; Qian, Yong-Zhong; Martínez-Pinedo, Gabriel; Fischer, Tobias; Huther, Lutz

    2015-03-01

    In this paper, we explore the effects of neutrino flavor oscillations on supernova nucleosynthesis and on the neutrino signals. Our study is based on detailed information about the neutrino spectra and their time evolution from a spherically symmetric supernova model for an 18 M⊙ progenitor. We find that collective neutrino oscillations are not only sensitive to the detailed neutrino energy and angular distributions at emission, but also to the time evolution of both the neutrino spectra and the electron density profile. We apply the results of neutrino oscillations to study the impact on supernova nucleosynthesis and on the neutrino signals from a Galactic supernova. We show that in our supernova model, collective neutrino oscillations enhance the production of rare isotopes 138La and 180Ta but have little impact on the ν p -process nucleosynthesis. In addition, the adiabatic Mikheyev-Smirnov-Wolfenstein flavor transformation, which occurs in the C /O and He shells of the supernova, may affect the production of light nuclei such as 7Li and 11B. For the neutrino signals, we calculate the rate of neutrino events in the Super-Kamiokande detector and in a hypothetical liquid argon detector. Our results suggest the possibility of using the time profiles of the events in both detectors, along with the spectral information of the detected neutrinos, to infer the neutrino mass hierarchy.

  3. NOVAS TECNOLOGIAS NO ENVELHECIMENTO

    Directory of Open Access Journals (Sweden)

    Rosa Maria Farah

    2010-02-01

    Full Text Available O Programa de Estudos Pós-Graduados em Gerontologia/PUC-SP desenvolve pesquisas em diversificadas linhas algumas das quais têm em comum o acolhimento à questão das novas tecnologias no envelhecimento. São investigações de caráter interdisciplinar que envolvem docentes-pesquisadores, orientandos de mestrado e de iniciação científica. Na área da educação a distância, a PUC-SP inaugura um trabalho em que o idoso interessado em avançar em seus conhecimentos é recebido em um ambiente virtual de aprendizagem, em que pode participar de cursos avançados de aquisição de novas linguagens e de navegação na Internet, cujas consequências são o investimento em uma via mais digna para o envelhecer no sentido de esse idoso sentir-se um ser ligado aos novos tempos em que a interatividade digital traz-lhe possibilidades ilimitadas de contatos com o outro, com o mundo enfim. A pesquisa sobre a inclusão cibersocial do idoso mostra o que significa colocar o idoso em contato com a Internet, quando este recebe, por meio das redes sociais, ofertas de várias ordens, e equipamentos que contornam limitações de ordem física ou motora. Além disso, o registro digital da memória do idoso, de sua história e referências também podem constituir conteudos preciosos para pesquisas. A relação do idoso com a informática pode situá-lo como um ator, produtor e reprodutor no ciberespaço. Isso significa que as vantagens do uso do computador fazem o idoso ganhar novo sentido na vida, na medida em que pode assim preencher o vazio causado pelas perdas que lhe vão ocorrendo, possibilitando que ele redimensione seu olhar para o presente e futuro. Palavras-chave: o sujeito-idoso nas novas tecnologias; novas tecnologias e envelhecimento; o idoso na educação a distância; internet na velhice.

  4. Toward a self-consistent and unitary reaction network for big bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Paris, Mark W.; Brown, Lowell S.; Hale, Gerald M.; Hayes-Sterbenz, Anna C.; Jungman, Gerard; Kawano, Toshihiko, E-mail: mparis@lanl.gov [Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Fuller, George M.; Grohs, Evan B. [Department of Physics, University of California, San Diego, La Jolla, CA (United States); Kunieda, Satoshi [Nuclear Data Center, Japan Atomic Energy Agency, Tokai-mura Naka-gun, Ibaraki (Japan)

    2014-07-01

    Unitarity, the mathematical expression of the conservation of probability in multichannel reactions, is an essential ingredient in the development of accurate nuclear reaction networks appropriate for nucleosynthesis in a variety of environments. We describe our ongoing program to develop a 'unitary reaction network' for the big-bang nucleosynthesis environment and look at an example of the need and power of unitary parametrizations of nuclear scattering and reaction data. Recent attention has been focused on the possible role of the {sup 9}B compound nuclear system in the resonant destruction of {sup 7}Li during primordial nucleosynthesis. We have studied reactions in the {sup 9}B compound system with a multichannel, two-body unitary R-matrix code (EDA) using the known elastic and reaction data, in a four-channel treatment. The data include elastic {sup 6}Li({sup 3}He,{sup 3}He){sup 6}Li differential cross sections from 0.7 to 2.0 MeV, integrated reaction cross sections for energies from 0.7 to 5.0 MeV for {sup 6}Li({sup 3}He,p){sup 8}Be* and from 0.4 to 5.0 MeV for the {sup 6}Li({sup 3}He,γ){sup 7}Be reaction. Capture data have been added to the previous analysis with integrated cross section measurements from 0.7 to 0.825 MeV for {sup 6}Li({sup 3}He,γ){sup 9}B. The resulting resonance parameters are compared with tabulated values from TUNL Nuclear Data Group analyses. Previously unidentified resonances are noted and the relevance of this analysis and a unitary reaction network for big-bang nucleosynthesis are emphasized. (author)

  5. Toward a self-consistent and unitary reaction network for big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Paris, Mark W.; Brown, Lowell S.; Hale, Gerald M.; Hayes-Sterbenz, Anna C.; Jungman, Gerard; Kawano, Toshihiko; Fuller, George M.; Grohs, Evan B.; Kunieda, Satoshi

    2014-01-01

    Unitarity, the mathematical expression of the conservation of probability in multichannel reactions, is an essential ingredient in the development of accurate nuclear reaction networks appropriate for nucleosynthesis in a variety of environments. We describe our ongoing program to develop a 'unitary reaction network' for the big-bang nucleosynthesis environment and look at an example of the need and power of unitary parametrizations of nuclear scattering and reaction data. Recent attention has been focused on the possible role of the 9 B compound nuclear system in the resonant destruction of 7 Li during primordial nucleosynthesis. We have studied reactions in the 9 B compound system with a multichannel, two-body unitary R-matrix code (EDA) using the known elastic and reaction data, in a four-channel treatment. The data include elastic 6 Li( 3 He, 3 He) 6 Li differential cross sections from 0.7 to 2.0 MeV, integrated reaction cross sections for energies from 0.7 to 5.0 MeV for 6 Li( 3 He,p) 8 Be* and from 0.4 to 5.0 MeV for the 6 Li( 3 He,γ) 7 Be reaction. Capture data have been added to the previous analysis with integrated cross section measurements from 0.7 to 0.825 MeV for 6 Li( 3 He,γ) 9 B. The resulting resonance parameters are compared with tabulated values from TUNL Nuclear Data Group analyses. Previously unidentified resonances are noted and the relevance of this analysis and a unitary reaction network for big-bang nucleosynthesis are emphasized. (author)

  6. Coalfields west half Cumberland County, Nova Scotia

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, M J

    1958-01-01

    A geologic survey of the coal fields of the western half of Cumberland County, Nova Scotia was performed including studies of the structural geology, stratigraphy, and paleontology of the area. One part of this survey included a spectrographic analysis of 55 coals for 23 elements. These analyses are presented in tabular form.

  7. Trojan Horse cross section measurements and their impact on primordial nucleosynthesis

    Science.gov (United States)

    Pizzone, R. G.; Spartá, R.; Bertulani, C.; Spitaleri, C.; La Cognata, M.; Lamia, L.; Mukhamedzhanov, A.; Tumino, A.

    2018-01-01

    Big Bang Nucleosynthesis (BBN) nucleosynthesis requires several nuclear physics inputs and, among them, an important role is played by nuclear reaction rates. They are among the most important input for a quantitative description of the early Universe. An up-to-date compilation of direct cross sections of d(d,p)t, d(d,n)3He and 3He(d,p)4He reactions is given, being these ones among the most uncertain bare-nucleus cross sections. An intense experimental effort has been carried on in the last decade to apply the Trojan Horse Method (THM) to study reactions of relevance for the BBN and measure their astrophysical S(E)-factor. The result of these recent measurements is reviewed and compared with the available direct data. The reaction rates and the relative error for the four reactions of interest are then numerically calculated in the temperature ranges of relevance for BBN (0.01nucleosynthesis calculations in order to evaluate their impact on the calculated primordial abundances of D, 3,4He and 7Li. These ones were then compared with the observational primordial abundance estimates in different astrophysical sites. A comparison was also performed with calculations using other reaction rates compilations available in literature.

  8. Fission and r-process nucleosynthesis in neutron star mergers

    International Nuclear Information System (INIS)

    Giuliani, Samuel Andrea

    2018-01-01

    Fission plays a crucial role for the r-process nucleosynthesis in neutron star mergers. Due to the high neutron densities achieved in this astrophysical scenario the sequence of neutron captures and beta decays that constitutes the r process produces superheavy neutron rich nuclei that become unstable against fission. Fission determines thus the heaviest nuclei that can be produced by the r process and the fission yields shape the abundances of lighter nuclei. But despite the key role of fission the sensitivity of the r-process nucleosynthesis to uncertainties in fission predictions has not been explored. Nowadays there are only few set of fission rates suited for r-process calculations and most of them rely on a simplified treatment of the fission process. In this thesis we go beyond these approximations and compute the fission properties of r-process nuclei using the energy density functional approach. Fission is described as a tunneling process where the nucleus ''moves'' in a collective space characterized by coordinates describing the nuclear shape. Thus fission depends on the evolution of the energy with the deformation but also on the inertia due to the motion in the collective space. This is analogous to the quantum mechanical tunneling of a particle inside a potential well. In our study the relevant quantities for the description of the fission process are consistently computed for 3642 nuclei following the Hartree-Fock-Bogolyubov theory with constraining operators. We perform an extensive benchmark against the available experimental data and explore the variations of the fission properties along the superheavy landscape. We find that while collective inertias have a strong impact in the fission probabilities of light nuclei their role becomes less relevant in r -process nuclei. Within the statistical model we compute the neutron induced stellar reaction rates relevant for the r-process nucleosynthesis. These sets of stellar reaction

  9. Franchising in Nova Scotia

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, G. [Nova Scotia Petroleum Directorate, Halifax, NS (Canada)

    1998-09-01

    Opportunities for the local distribution of natural gas in Nova Scotia were reviewed, with special emphasis on franchising. Franchising in Nova Scotia began in 1980, made possible by the passage of the Gas Utilities Act and the Pipeline Act which promised western Canadian natural gas to eastern Canada. However, proposals for franchisees to distribute natural gas in the province were abandoned as the hope for natural gas transmission service to the province faded. The plummeting of world oil prices by the mid-1980s was also a contributory factor. Discovery and development of natural gas facilities around Sable Island led to the September 1997 proclamation of the Gas Distribution Act, which also led to the revival of interest in franchising. The Act provides for the competitive marketing of natural gas as a commodity and the regulation of the gas delivery system under a franchise agreement. Competitive applications are expected early in 1998, with awards of franchises in late 1998. Construction and gas delivery services should begin operations late in 1999.

  10. Franchising in Nova Scotia

    International Nuclear Information System (INIS)

    Hoffman, G.

    1998-01-01

    Opportunities for the local distribution of natural gas in Nova Scotia were reviewed, with special emphasis on franchising. Franchising in Nova Scotia began in 1980, made possible by the passage of the Gas Utilities Act and the Pipeline Act which promised western Canadian natural gas to eastern Canada. However, proposals for franchisees to distribute natural gas in the province were abandoned as the hope for natural gas transmission service to the province faded. The plummeting of world oil prices by the mid-1980s was also a contributory factor. Discovery and development of natural gas facilities around Sable Island led to the September 1997 proclamation of the Gas Distribution Act, which also led to the revival of interest in franchising. The Act provides for the competitive marketing of natural gas as a commodity and the regulation of the gas delivery system under a franchise agreement. Competitive applications are expected early in 1998, with awards of franchises in late 1998. Construction and gas delivery services should begin operations late in 1999

  11. Outbursts of symbiotic novae

    International Nuclear Information System (INIS)

    Kenyon, S.J.; Truran, J.W.

    1983-01-01

    We discuss possible conditions under which thermonuclear burning episodes in the hydrogen-rich envelopes of accreting white dwarfs give rise to outbursts similar in nature to those observed in the symbiotic stars AG Peg, RT Ser, RR Tel, AS 239, V1016 Cyg, V1329 Cyg, and HM Sge. In principle, thermonuclear runaways involving low-luminosity white dwarfs accreting matter at low rates produce configurations that evolve into A--F supergiants at maximum visual light and which resemble the outbursts of RR Tel, RT Ser, and AG peg. Very weak, nondegenerage hydrogen shell flashes on white dwarfs accreting matter at high rates (M> or approx. =10 -8 M/sub sun/ yr -1 ) do not produce cool supergiants at maximum, and may explain the outbursts in V1016 Cyg, V1329 Cyg, and HM Sge. The low accretion rates demanded for systems developing strong hydrogen shell flashes on low-luminsoity white dwarfs are not compatible with observations of ''normal'' quiescent symbiotic stars. The extremely slow outbursts of symbiotic novae appear to be typical of accreting white dwarfs in wide binaries, which suggests that the outbursts of classical novae may be accelerated by the interaction of the expanding white dwarf envelope with its close binary companion

  12. What's Next for Big Bang Nucleosynthesis?

    International Nuclear Information System (INIS)

    Cyburt, R.H.

    2005-01-01

    Big bang nucleosynthesis (BBN) plays an important role in the standard hot big bang cosmology. BBN theory is used to predict the primordial abundances of the lightest elements, hydrogen, helium and lithium. Comparison between the predicted and observationally determined light element abundances provides a general test of concordance and can be used to fix the baryon content in the universe. Measurements of the cosmic microwave background (CMB) anisotropies now supplant BBN as the premier baryometer, especially with the latest results from the WMAP satellite. With the WMAP baryon density, the test of concordance can be made even more precise. Any disagreement between theory predictions and observations requires careful discussion. Several possibilities exist to explain discrepancies; (1) observational systematics (either physical or technical) may not be properly treated in determining primordial light element abundances (2) nuclear inputs that determine the BBN predictions may have unknown systematics or may be incomplete, and (3) physics beyond that included in the standard BBN scenario may need to be included in the theory calculation. Before we can be absolutely sure new physics is warranted, points (1) and (2) must be addressed and ruled out. All of these scenarios rely on experimental or observational data to make definitive statements of their applicability and range of validity, which currently is not at the level necessary to discern between these possibilities with high confidence. Thus, new light element abundance observations and nuclear experiments are needed to probe these further. Assuming concordance is established, one can use the light element observations to explore the evolution from their primordial values. This can provide useful information on stellar evolution, cosmic rays and other nuclear astrophysics. When combined with detailed models, BBN, the CMB anisotropy and nuclear astrophysics can provide us with information about the populations

  13. AGB nucleosynthesis in the Large Magellanic Cloud. Detailed abundance analysis of the RV Tauri star MACHO 47.2496.8

    NARCIS (Netherlands)

    Reyniers, M.; Abia, C.; van Winckel, H.; Lloyd Evans, T.; Decin, L.K.E.; Eriksson, K.; Pollard, K.R.

    2007-01-01

    Context: .Abundance analysis of post-AGB objects as probes of AGB nucleosynthesis. Aims: .A detailed photospheric abundance study is performed on the carbon-rich post-AGB candidate MACHO 47.2496.8 in the LMC. Methods: .High-resolution, high signal-to-noise ESO VLT-UVES spectra of MACHO 47.2496.8 are

  14. Estudos da linguagem e mente corporificada: uma nova proposta gramatical Studies of language and embodied mind: a new grammar approach

    Directory of Open Access Journals (Sweden)

    Ricardo Yamashita Santos

    2011-01-01

    Full Text Available Podemos dizer que Descartes fundamentou a filosofia moderna com uma proposta universal do entendimento mundano. Dissociando as experiências corpóreas de nossa matéria pensante - mente, conseguiríamos captar a verdadeira essência de tudo por meio de um pensamento racional e objetivo. A ideia de mente corporificada, traduzida aqui pelos moldes de Lakoff e Johnson (1980, quebra com a dicotomia do filósofo e com diversas outras tradições enraizadas em nossa cultura ocidental. Nosso objetivo neste artigo é o de amparar a nova proposta teórica de mente corporificada e pensar um novo modelo gramatical que evidencie a corporalidade da mente.We can say that Descartes founded the modern philosophy with an universal proposal of the mundane understanding. Dissociating the bodily experience from our thinking matter - mind, we could capture the true essence of everything through rational and objective thought. The idea of the embodied mind, translated here by Lakoff and Johnson's theories (1980, breaks Descartes' dichotomy and various other traditions rooted in our Western culture. Our goals in this paper is to bolster the new theoretical proposition of embodied mind and think about a new grammatical model that highlights the embodiment of mind.

  15. Supernova nucleosynthesis and the physics of neutrino oscillation

    Energy Technology Data Exchange (ETDEWEB)

    Kajino, Toshitaka [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan) and Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2012-11-20

    We studied the explosive nucleosynthesis in core-collapse supernovae and found that several isotopes of rare elements like {sup 7}Li, {sup 11}B, {sup 138}La, {sup 180}Ta and others are predominantly produced by the neutrino interactions with several abundant nuclei. These isotopes are strongly affected by the neutrino flavor oscillation due to the MSW (Mikheyev-Smirnov-Wolfenstein) effect. We here first study how to know the suitable average neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the neutrino oscillation effects on their abundances, and propose a new novel method to determine the neutrino oscillation parameters, {theta}{sub 13} and mass hierarchy, simultaneously. There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced neutrino-process {sup 11}B and {sup 7}Li encapsulated in the grains. Combining the recent experimental constraints on {theta}{sub 13}, we show that although the uncertainties are still large, our method hints at a marginal preference for an inverted neutrino mass hierarchy for the first time.

  16. Supernova nucleosynthesis and the physics of neutrino oscillation

    Science.gov (United States)

    Kajino, Toshitaka

    2012-11-01

    We studied the explosive nucleosynthesis in core-collapse supernovae and found that several isotopes of rare elements like 7Li, 11B, 138La, 180Ta and others are predominantly produced by the neutrino interactions with several abundant nuclei. These isotopes are strongly affected by the neutrino flavor oscillation due to the MSW (Mikheyev-Smirnov-Wolfenstein) effect. We here first study how to know the suitable average neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the neutrino oscillation effects on their abundances, and propose a new novel method to determine the neutrino oscillation parameters, θ13 and mass hierarchy, simultaneously. There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced neutrino-process 11B and 7Li encapsulated in the grains. Combining the recent experimental constraints on θ13, we show that although the uncertainties are still large, our method hints at a marginal preference for an inverted neutrino mass hierarchy for the first time.

  17. Nucleosynthesis in the early Galaxy: Progress and challenges.

    Science.gov (United States)

    Montes, Fernando

    2015-10-01

    Chemical imprints left by the first stars in the oldest stars of the Milky Way gives clues of the stellar nucleosynthesis responsible for the creation of elements heavier than iron. Recent progress in astronomical observations and in the modeling of the chemical evolution of the Galaxy have shown that multiple nucleosynthesis processes may operate at those early times. In this talk I will review some of that evidence along with the important role that nuclear reactions play in those processes. I will focus in progress in our understanding of the rapid neutron capture process (r-process) and in new results on nucleosynthesis in core-collapse supernovae and neutrino-driven winds that produce elements up to silver. I will show some examples of recent nuclear physics measurements addressing the need for better nuclear data and give an outlook of the remaining challenges and future plans to continue those measurements.

  18. Big bang nucleosynthesis revisited via Trojan Horse method measurements

    Energy Technology Data Exchange (ETDEWEB)

    Pizzone, R. G.; Spartá, R.; Spitaleri, C.; La Cognata, M.; Tumino, A. [INFN—Laboratori Nazionali del Sud, Via Santa Sofia 62, I-95123 Catania (Italy); Bertulani, C. A.; Lalmansingh, J. [Department of Physics and Astronomy, Texas A and M University, Commerce, TX 75025 (United States); Lamia, L. [Dipartimento di Fisica e Astronomia, Università degli Studi di Catania, Via Santa Sofia 64, I-95123 Catania (Italy); Mukhamedzhanov, A., E-mail: rgpizzone@lns.infn.it [Cyclotron Institute, Texas A and M University, College Station, TX 77843 (United States)

    2014-05-10

    Nuclear reaction rates are among the most important input for understanding primordial nucleosynthesis and, therefore, for a quantitative description of the early universe. An up-to-date compilation of direct cross-sections of {sup 2}H(d, p){sup 3}H, {sup 2}H(d, n){sup 3}He, {sup 7}Li(p, α){sup 4}He, and {sup 3}He(d, p){sup 4}He reactions is given. These are among the most uncertain cross-sections used and input for big bang nucleosynthesis calculations. Their measurements through the Trojan Horse method are also reviewed and compared with direct data. The reaction rates and the corresponding recommended errors in this work were used as input for primordial nucleosynthesis calculations to evaluate their impact on the {sup 2}H, {sup 3,4}He, and {sup 7}Li primordial abundances, which are then compared with observations.

  19. Big-Bang nucleosynthesis with updated nuclear data

    Energy Technology Data Exchange (ETDEWEB)

    Coc, Alain [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), CNRS/IN2P3, Universite Paris Sud 11, UMR 8609, Batiment 104, F-91405 Orsay Campus (France); Vangioni, Elisabeth, E-mail: Alain.Coc@csnsm.in2p3.f, E-mail: vangioni@iap.f [Institut d' Astrophysique de Paris, UMR-7095 du CNRS, Universite Pierre et Marie Curie, 98 bis bd Arago, 75014 Paris (France)

    2010-01-01

    Primordial nucleosynthesis is one of the three evidences for the Big-Bang model together with the expansion of the Universe and the Cosmic Microwave Background. There is a good global agreement over a range of nine orders of magnitude between abundances of {sup 4}He, D, {sup 3}He and {sup 7}Li deduced from observations and calculated primordial nucleosynthesis. This comparison was used to determine the baryonic density of the Universe. For this purpose, it is now superseded by the analysis of the Cosmic Microwave Background (CMB) radiation anisotropies. Big-Bang nucleosynthesis remains, nevertheless, a valuable tool to probe the physics of the early Universe. However, the yet unexplained, discrepancy between the calculated and observed lithium primordial abundances, has not been reduced, neither by recent nuclear physics experiments, nor by new observations.

  20. Introduction to big bang nucleosynthesis and modern cosmology

    Science.gov (United States)

    Mathews, Grant J.; Kusakabe, Motohiko; Kajino, Toshitaka

    Primordial nucleosynthesis remains as one of the pillars of modern cosmology. It is the testing ground upon which many cosmological models must ultimately rest. It is our only probe of the universe during the important radiation-dominated epoch in the first few minutes of cosmic expansion. This paper reviews the basic equations of space-time, cosmology, and big bang nucleosynthesis. We also summarize the current state of observational constraints on primordial abundances along with the key nuclear reactions and their uncertainties. We summarize which nuclear measurements are most crucial during the big bang. We also review various cosmological models and their constraints. In particular, we analyze the constraints that big bang nucleosynthesis places upon the possible time variation of fundamental constants, along with constraints on the nature and origin of dark matter and dark energy, long-lived supersymmetric particles, gravity waves, and the primordial magnetic field.

  1. Nova Scotia Power : in-stream tidal

    International Nuclear Information System (INIS)

    Meade, K.

    2007-01-01

    The Government of Nova Scotia, the Government of New Brunswick, Nova Scotia Power and others have funded a feasibility study of North American sites for commercial instream tidal power. In July 2007, Nova Scotia Power received partial funding for a demonstration project. This presentation provided information on a demonstration plant for tidal power run by Nova Scotia Power. It discussed the benefits of the Open Hydro technology for this plant. In this simple design, the generator is on the circumference of the turbine. The design does not involve any power transmission systems or any pitching of blades. In addition, the technology is environmentally sound as it is completely shrouded, has low rotational speed, and a large open centre allows fish to pass through, and it does not require lubricants. The last benefit that was presented was the scale up of 250 kW machine deployed in a European test facility. The presentation also discussed the advantages of developing tidal power at this time. It was concluded that tidal energy has significant potential. Although it is intermittent, it is predictable and bulk power system can be scheduled to accommodate it. figs

  2. Nonuniversal scalar-tensor theories and big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Coc, Alain; Olive, Keith A.; Uzan, Jean-Philippe; Vangioni, Elisabeth

    2009-01-01

    We investigate the constraints that can be set from big bang nucleosynthesis on two classes of models: extended quintessence and scalar-tensor theories of gravity in which the equivalence principle between standard matter and dark matter is violated. In the latter case, and for a massless dilaton with quadratic couplings, the phase space of theories is investigated. We delineate those theories where attraction toward general relativity occurs. It is shown that big bang nucleosynthesis sets more stringent constraints than those obtained from Solar System tests.

  3. The quark-hadron phase transition and primordial nucleosynthesis

    Science.gov (United States)

    Hogan, Craig J.

    1987-01-01

    After presenting the current view of the processes taking place during the cosmological transition from 'quark soup' to normal hadron matter, attention is given to what happens to cosmological nucleosynthesis in the presence of small-scale baryon inhomogeneities. The QCD phase transition is among the plausible sources of this inhomogeneity. It is concluded that the formation of primordial 'quark nuggets' and other cold exotica requires very low entropy regions at the outset, and that even the more modest nonlinearities perturbing nucleosynthesis probably require some ingredient in addition to a quiescent, mildly supercooled transition.

  4. Nonuniversal scalar-tensor theories and big bang nucleosynthesis

    Science.gov (United States)

    Coc, Alain; Olive, Keith A.; Uzan, Jean-Philippe; Vangioni, Elisabeth

    2009-05-01

    We investigate the constraints that can be set from big bang nucleosynthesis on two classes of models: extended quintessence and scalar-tensor theories of gravity in which the equivalence principle between standard matter and dark matter is violated. In the latter case, and for a massless dilaton with quadratic couplings, the phase space of theories is investigated. We delineate those theories where attraction toward general relativity occurs. It is shown that big bang nucleosynthesis sets more stringent constraints than those obtained from Solar System tests.

  5. Nova Gas's pipeline to Asia

    International Nuclear Information System (INIS)

    Lea, N.

    1996-01-01

    The involvement of the Calgary-based company NOVA Gas International (NGI) in Malaysia's peninsular gas utilization (PGU) project, was described. Phase I and II of the project involved linking onshore gas processing plants with a natural gas transmission system. Phase III of the PGU project was a gas transmission pipeline that began midway up the west coast of peninsular Malaysia to the Malaysia-Thailand border. The complex 549 km pipeline included route selection, survey and soil investigation, archaeological study, environmental impact assessment, land acquisition, meter-station construction, telecommunication systems and office buildings. NGI was the prime contractor on the project through a joint venture with OGP Technical Services, jointly owned by NGI and Petronas, the Thai state oil company. Much of NGI's success was attributed to excellent interpersonal skills, particularly NGI's ability to build confidence and credibility with its Thai partners

  6. Big Bang Nucleosynthesis and Cosmological Constraints on Neutrino Oscillation Parameters

    CERN Document Server

    Kirilova, Daniela P; Kirilova, Daniela; Chizhov, Mihail

    2001-01-01

    We present a review of cosmological nucleosynthesis (CN) with neutrino oscillations, discussing the different effects of oscillations on CN, namely: increase of the effective degrees of freedom during CN, spectrum distortion of the oscillating neutrinos, neutrino number density depletion, and growth of neutrino-antineutrino asymmetry due to active-sterile oscillations. We discuss the importance of these effects for the primordial yield of helium-4. Primordially produced He-4 value is obtained in a selfconsistent study of the nucleons and the oscillating neutrinos. The effects of spectrum distortion, depletion and neutrino-antineutrino asymmetry growth on helium-4 production are explicitly calculated. An update of the cosmological constraints on active-sterile neutrino oscillations parameters is presented, giving the values: delta m^2 sin^8 (2 theta) 0, and |delta m^2| < 8.2 x 10^{-10} eV^2 at large mixing angles for delta m^2 < 0. According to these constraints, besides the active-sterile LMA solution,...

  7. Nova Event Logging System

    International Nuclear Information System (INIS)

    Calliger, R.J.; Suski, G.J.

    1981-01-01

    Nova is a 200 terawatt, 10-beam High Energy Glass Laser currently under construction at LLNL. This facility, designed to demonstrate the feasibility of laser driven inertial confinement fusion, contains over 5000 elements requiring coordinated control, data acquisition, and analysis functions. The large amounts of data that will be generated must be maintained over the life of the facility. Often the most useful but inaccessible data is that related to time dependent events associated with, for example, operator actions or experiment activity. We have developed an Event Logging System to synchronously record, maintain, and analyze, in part, this data. We see the system as being particularly useful to the physics and engineering staffs of medium and large facilities in that it is entirely separate from experimental apparatus and control devices. The design criteria, implementation, use, and benefits of such a system will be discussed

  8. RECURRENT NOVAE IN M31

    Energy Technology Data Exchange (ETDEWEB)

    Shafter, A. W. [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States); Henze, M. [European Space Astronomy Centre, P.O. Box 78, E-28692 Villanueva de la Cañada, Madrid (Spain); Rector, T. A. [Department of Physics and Astronomy, University of Alaska Anchorage, 3211 Providence Dr., Anchorage, AK 99508 (United States); Schweizer, F. [Carnegie Observatories, 813 Santa Barbara St., Pasadena, CA 91101 (United States); Hornoch, K. [Astronomical Institute, Academy of Sciences, CZ-251 65 Ondřejov (Czech Republic); Orio, M. [Astronomical Observatory of Padova (INAF), I-35122 Padova (Italy); Pietsch, W. [Max Planck Institute for Extraterrestrial Physics, P.O. Box 1312, Giessenbachstr., D-85741, Garching (Germany); Darnley, M. J.; Williams, S. C.; Bode, M. F. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool L3 5RF (United Kingdom); Bryan, J., E-mail: aws@nova.sdsu.edu [McDonald Observatory, Austin, TX 78712 (United States)

    2015-02-01

    The reported positions of 964 suspected nova eruptions in M31 recorded through the end of calendar year 2013 have been compared in order to identify recurrent nova (RN) candidates. To pass the initial screen and qualify as a RN candidate, two or more eruptions were required to be coincident within 0.′1, although this criterion was relaxed to 0.′15 for novae discovered on early photographic patrols. A total of 118 eruptions from 51 potential RN systems satisfied the screening criterion. To determine what fraction of these novae are indeed recurrent, the original plates and published images of the relevant eruptions have been carefully compared. This procedure has resulted in the elimination of 27 of the 51 progenitor candidates (61 eruptions) from further consideration as RNe, with another 8 systems (17 eruptions) deemed unlikely to be recurrent. Of the remaining 16 systems, 12 candidates (32 eruptions) were judged to be RNe, with an additional 4 systems (8 eruptions) being possibly recurrent. It is estimated that ∼4% of the nova eruptions seen in M31 over the past century are associated with RNe. A Monte Carlo analysis shows that the discovery efficiency for RNe may be as low as 10% that for novae in general, suggesting that as many as one in three nova eruptions observed in M31 arise from progenitor systems having recurrence times ≲100 yr. For plausible system parameters, it appears unlikely that RNe can provide a significant channel for the production of Type Ia supernovae.

  9. The NOvA software testing framework

    International Nuclear Information System (INIS)

    Tamsett, M; Group, C

    2015-01-01

    The NOvA experiment at Fermilab is a long-baseline neutrino experiment designed to study vε appearance in a vμ beam. NOvA has already produced more than one million Monte Carlo and detector generated files amounting to more than 1 PB in size. This data is divided between a number of parallel streams such as far and near detector beam spills, cosmic ray backgrounds, a number of data-driven triggers and over 20 different Monte Carlo configurations. Each of these data streams must be processed through the appropriate steps of the rapidly evolving, multi-tiered, interdependent NOvA software framework. In total there are greater than 12 individual software tiers, each of which performs a different function and can be configured differently depending on the input stream. In order to regularly test and validate that all of these software stages are working correctly NOvA has designed a powerful, modular testing framework that enables detailed validation and benchmarking to be performed in a fast, efficient and accessible way with minimal expert knowledge. The core of this system is a novel series of python modules which wrap, monitor and handle the underlying C++ software framework and then report the results to a slick front-end web-based interface. This interface utilises modern, cross-platform, visualisation libraries to render the test results in a meaningful way. They are fast and flexible, allowing for the easy addition of new tests and datasets. In total upwards of 14 individual streams are regularly tested amounting to over 70 individual software processes, producing over 25 GB of output files. The rigour enforced through this flexible testing framework enables NOvA to rapidly verify configurations, results and software and thus ensure that data is available for physics analysis in a timely and robust manner. (paper)

  10. Synoptic GNIRS XD Spectra ToO Novae

    Science.gov (United States)

    Woodward, Chick; Helton, Andrew; Spitzer/Chandra Team

    2007-02-01

    Novae are important contributors to galactic chemical enrichment on local scales. NIR spectroscopy of novae provides information about the elemental abundances of the gas and dust in the ejecta dispersing into the ISM as well as kinematic information related to the outburst. We propose to obtain synoptic GNIRS spectra of select Target of Opportunity (ToO) novae in the Magellanic Clouds (MC) and the galaxy to study the dynamics of the ejecta, to determine the temporal evolution of coronal lines and recombination lines (measuring their strength and velocity profiles), and to determine abundances. Being all equidistant, MC nova permit a more robust analysis of distant-dependent physical parameters of outburst than is generally possible for Galactic novae. The GNIRS data will provide critical spectral coverage and synoptic data to complement extant Spitzer and Chandra nova programs. Triggering of the GNIRS program will occur when a nova becomes brighter than V=12 mag, (assuming that adequate PWFS guide stars exist) as reported in the IAUC or CBET.

  11. OGLE ATLAS OF CLASSICAL NOVAE. II. MAGELLANIC CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Mróz, P.; Udalski, A.; Poleski, R.; Soszyński, I.; Szymański, M. K.; Pietrzyński, G.; Wyrzykowski, Ł.; Ulaczyk, K.; Kozłowski, S.; Pietrukowicz, P.; Skowron, J., E-mail: pmroz@astrouw.edu.pl [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland)

    2016-01-15

    The population of classical novae in the Magellanic Clouds was poorly known because of a lack of systematic studies. There were some suggestions that nova rates per unit mass in the Magellanic Clouds were higher than in any other galaxy. Here, we present an analysis of data collected over 16 years by the OGLE survey with the aim of characterizing the nova population in the Clouds. We found 20 eruptions of novae, half of which are new discoveries. We robustly measure nova rates of 2.4 ± 0.8 yr{sup −1} (LMC) and 0.9 ± 0.4 yr{sup −1} (SMC) and confirm that the K-band luminosity-specific nova rates in both Clouds are 2–3 times higher than in other galaxies. This can be explained by the star formation history in the Magellanic Clouds, specifically the re-ignition of the star formation rate a few Gyr ago. We also present the discovery of the intriguing system OGLE-MBR133.25.1160, which mimics recurrent nova eruptions.

  12. PHOTOMETRIC AND SPECTROSCOPIC PROPERTIES OF NOVAE IN THE LARGE MAGELLANIC CLOUD

    International Nuclear Information System (INIS)

    Shafter, A. W.

    2013-01-01

    The photometric and spectroscopic properties of the 43 known LMC nova candidates are summarized and reviewed. Of these, photometric data sufficient to establish decline rates are available for 29 novae, while spectroscopic data sufficient to establish the spectroscopic classes are available for 18 systems. Half of the 18 novae belong to the Fe II class, with the remaining nine belonging to either the He/N or the Fe IIb classes. As seen in previous nova studies of M31 and M33, the He/N and Fe IIb novae have on average faster photometric developments than do their Fe II counterparts. Overall, the available photometry confirms earlier studies, and shows conclusively that LMC novae have faster rates of decline than do novae in the Galaxy and M31. It appears that the increased fraction of faster, He/N and Fe IIb novae observed in the LMC compared with M31 is almost certainly the result of differences in the underlying stellar population between the two galaxies. We propose that the younger population seen in the LMC compared with M31's bulge (where most of the novae are found), produces progenitor binaries with higher average white dwarf masses. The higher mean white dwarf mass not only produces a larger fraction of fast, He/N novae compared with M31, but also results in a relatively large recurrent nova population.

  13. Early nucleosynthesis, particle physics and the quark-lithium connection

    International Nuclear Information System (INIS)

    Reeves, H.; Audouze, J.; Delbourgo-Salvador, P.; Salati, P.; California Univ., Berkeley

    1987-01-01

    Three questions relevant to the primordial nucleosynthesis of the very light elements are discussed in this contribution: 1. It is argued that the ''standard'' Big Bang nucleosynthesis models are strenghtened if D is destroyed thoroughly during the galactic history. This can be achieved by specific models of chemical evolution of galaxies like those assuming a rate of star formation varying with time. 2. The existence of non baryonic particles such as massive neutrinos or supersymetric particles (gravitinos, photinos ...) might affect this early nucleosynthesis. If they are massive (≥ 500 MeV) and long lived enough (≥ 10 5 sec) the energetic photons released by their possible decay might affect the relative abundances of the light elements. In the case of the photinos, which are the supersymetric particles and which might be experimentally detectable in a near future, this possible effect can be used as to constrain the predictions on their physical properties (mass, lifetime...). 3. The early nucleosynthesis can be affected by the inhomogeneities triggered by the quark-hadron phase transition. It is argued that the primordial abundance of 7 Li limits very severely this possibility. As in the case of photinos the relation between the early synthesis of 7 Li and the characteristics of this quark-hadron phase transition may provide interesting constraints on some important physical parameters such as the constant B of the quark-bag model

  14. Big bang nucleosynthesis and the cosmic neutrino background

    International Nuclear Information System (INIS)

    Cao Yun; Xing Zhizhong

    2013-01-01

    We present a brief overview of the neutrino decoupling and big bang nucleosynthesis in the early universe. The big bang relic neutrinos formed one of the backgrounds of the universe. A few possible ways to directly detect the cosmic neutrino background are briefly introduced, and particular attention is paid to the relic neutrino capture on b-decaying nuclei. (authors)

  15. Collaborative Research: Neutrinos and Nucleosynthesis in Hot Dense Matter

    Energy Technology Data Exchange (ETDEWEB)

    McLaughlin, Gail [North Carolina State Univ., Raleigh, NC (United States); Schaefer, Thomas [North Carolina State Univ., Raleigh, NC (United States)

    2015-05-31

    The major accomplishments of the research activity at NC State during the five years were: to determine the effects and signatures of turbulence in supernova, to calculate r-process and supernova nucleosynthesis, and to determine the neutrino scattering and flavor transformation that occurs in black hole accretion disks. This report goes into more detail on them.

  16. Recurrent Novae — A Review

    Directory of Open Access Journals (Sweden)

    K. Mukai

    2015-02-01

    Full Text Available In recent years, recurrent nova eruptions are often observed very intensely in wide range of wavelengths from radio to optical to X-rays. Here I present selected highlights from recent multi-wavelength observations. The enigma of T Pyx is at the heart of this paper. While our current understanding of CV and symbiotic star evolution can explain why certain subset of recurrent novae have high accretion rate, that of T Pyx must be greatly elevated compared to the evolutionary mean. At the same time, we have extensive data to be able to estimate how the nova envelope was ejected in T Pyx, and it turns to be a rather complex tale. One suspects that envelope ejection in recurrent and classical novae in general is more complicated than the textbook descriptions. At the end of the review, I will speculate that these two may be connected.

  17. Primordial nucleosynthesis as a probe of particle physics and cosmology

    International Nuclear Information System (INIS)

    Walker, T.P.

    1987-01-01

    In this dissertation, the author uses the success of the standard model of big-bang nucleosynthesis to examine the effects of interacting particle species and the effect of varying coupling constants, predicted by theories set in extra dimensions, on primordial nucleosynthesis. A review is given of the standard model and of the abundances of the light elements expected to be produced in the early Universe. The weakest piece of the concordance between the standard model of big-bang nucleosynthesis and observation is the production and primordial abundance of 7 Li. Therefore he discusses the production of 7 Li in astrophysical environments other than the early Universe and shows that the predictions of big-bang nucleosynthesis, when supplemented by those due to astrophysical sources, are in good agreement with observation. He then shows that the effect on big-bang nucleosynthesis of an additional particle species which remains coupled to either photons or light neutrinos can be quite different from that predicted by the equivalent number of neutrino species parameterization, which does work for decoupled additional species. In particular he considers the case of an additional axion-like particle and shows that its effect is to decrease the amount of 4 He produced in the big-bang. In addition, he considers the effects of varying coupling constants on 4 He production in the big-bang and shows that constraining Y p = 0.24 ± 0.01 leads to a constraint on the time variation of the fine-structure constant of |dln α/dt| ≤ x 10 -14

  18. Statistical analysis of dwarf nova outbursts

    International Nuclear Information System (INIS)

    Gicger, A.

    1987-01-01

    Correlation between maximum brightness, outburst width, lengths of preceding and following intervals has been studied for 14 dwarf novae (mostly from southern sky). Significant correlations (ρ ≥ 0.4) occur only in 16 per cent of cases, what confirms earlier results of Szkody and Mattei (1984). Global correlations have also been studied between mean photometric parameters and binary system parameters using a sample including over 30 objects. The most interesting result is the strong correlation (ρ = +0.94) between the orbital period and the outburst duration. It implies that the quantity α(z 0 /r) 2 is approximately constant for all dwarf novae. Using typical estimates for z 0 /r we get α = 0.2. 30 refs., 1 figs., 2 tabs. (author)

  19. Review of the classical nova outburst

    International Nuclear Information System (INIS)

    Starrfield, S.; Sparks, W.M.

    1986-06-01

    Observational studies have not only identified a new class of novae but theoretical simulations of this class have been found to be in excellent agreement with the observations. This new class consists of outbursts occurring on ONeMg white dwarfs in close binar systems in contrast to the other outbursts which are occurring on CO white dwarfs. We also review the effects of the β + -unstable nuclei and show how their presence has a major effect on the evolution. 77 refs

  20. Mechanical construction of the 22 Nova laser

    International Nuclear Information System (INIS)

    Hurley, C.A.; Frick, F.A.; Patton, H.G.; Bradley, G.; Martos, A.

    1983-01-01

    The Nova laser system for Inertial Confinement Fusion studies at Lawrence Livermore National Laboratory is under construction and will be completed October 1984 with first operations scheduled for 1985. This system is the largest precision opto-mechanical engineering system ever built. Major engineering and subsystems are mechanical, optical, and electrical power. A series of system technologies include alignment, diagnostics, target, frequency conversion, and controls. This paper will only discuss the mechanical system

  1. On Presolar Stardust Grains from CO Classical Novae

    Science.gov (United States)

    Iliadis, Christian; Downen, Lori N.; José, Jordi; Nittler, Larry R.; Starrfield, Sumner

    2018-03-01

    About 30%–40% of classical novae produce dust 20–100 days after the outburst, but no presolar stardust grains from classical novae have been unambiguously identified yet. Although several studies claimed a nova paternity for certain grains, the measured and simulated isotopic ratios could only be reconciled, assuming that the grains condensed after the nova ejecta mixed with a much larger amount of close-to-solar matter. However, the source and mechanism of this potential post-explosion dilution of the ejecta remains a mystery. A major problem with previous studies is the small number of simulations performed and the implied poor exploration of the large nova parameter space. We report the results of a different strategy, based on a Monte Carlo technique, that involves the random sampling over the most important nova model parameters: the white dwarf composition; the mixing of the outer white dwarf layers with the accreted material before the explosion; the peak temperature and density; the explosion timescales; and the possible dilution of the ejecta after the outburst. We discuss and take into account the systematic uncertainties for both the presolar grain measurements and the simulation results. Only those simulations that are consistent with all measured isotopic ratios of a given grain are accepted for further analysis. We also present the numerical results of the model parameters. We identify 18 presolar grains with measured isotopic signatures consistent with a CO nova origin, without assuming any dilution of the ejecta. Among these, the grains G270_2, M11-334-2, G278, M11-347-4, M11-151-4, and Ag26 have the highest probability of a CO nova paternity.

  2. A nova ordem repressiva

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Ceccarelli

    Full Text Available Segundo o autor, a humanidade sempre foi marcada por alguma forma de controle de acordo com o discurso do momento sociohistórico que atravessa: esse texto discute alguns instrumentos de controle e repressão da contemporaneidade. Se, por séculos, foi a religião que ditou as normas sociais, na modernidade, as verdades religiosas foram substituídas por enunciados científicos que sugeriam uma linearidade histórica e propunham uma compreensão determinista do mundo, baseada na capacidade da ciência em dar respostas. As certezas da modernidade foram radicalmente questionadas na pósmodernidade, fazendo surgir outros mecanismos de controle. Para o autor, a necessidade do ser humano de criar representações e dispositivos para suportar e nomear a angústia inerente ao desamparo que lhe é próprio o leva a submeter-se aos mais variados discursos repressivos. O discurso científico atual vem sendo transformado em instrumento ideológico que, com as inúmeras expressões do politicamente correto, traduzem uma busca de normatização e de padronização de comportamentos, gerando uma nova ordem repressiva. No que diz respeito à saúde psíquica, os manuais de diagnóstico, financiados pela indústria farmacêutica, transformam comportamentos, individualidades e diversidades em patologias: as singularidades tornam-se anormalidades. Qual é o compromisso social dos psicólogos nesse debate?

  3. Nova Scotia electricity update

    International Nuclear Information System (INIS)

    Crandlemire, A.L.

    2004-01-01

    This paper provides an update of electricity issues concerning Nova Scotia such as supply, capacity, emission commitments, as well as co-generation and the Electricity Marketplace Governance Committee (EMGC). The goals of the strategy were reliability combined with competitive prices and greater environmental responsibility. The scope of these objectives included new capacity, transmission, renewables and co-generation. Other objectives included encouraging wholesale market competition; meeting reciprocity requirements; and a 50 MW renewable energy target. Recommendations of the EMGC included wholesale market competition; a broader market scope with a cost benefit analysis; Open Access Transmission Tariff (OATT); a scheduling and information system; network integration and a point to point service; and a separation of transmission and generation business units. Other recommendations included an open competitive process for new generation; a consideration of emissions and overall efficiency; a Renewable Energy Portfolio Standard (RPS) to start in 2006; the separation of RPS tags from electricity; and net metering of renewables. These recommendations were accepted in 2003, followed by the new Electricity Act in 2004, which made OATT mandatory, established RPS and opened to the wholesale market. Capacity at present was considered to be tight, with preparations for the new regulations under way. Reductions in air pollution were reported at 25 per cent, with renewable energy projects such as 2 windmills currently under way, as well as various other projects. Opportunities for provincial Atlantic cooperation were identified as being management of reserve requirements; trading of lowest cost electricity; new generation on a regional scale; stronger transmission ties; a system operator; a regional approach to RPS; regional management of air emissions; and regional opportunities for Carbon dioxide reductions. tabs., figs

  4. Pollination, seed set and fruit quality in apple: studies with Osmia lignaria (Hymenoptera: Megachilidae in the Annapolis Valley, Nova Scotia, Canada

    Directory of Open Access Journals (Sweden)

    Cory Silas Sheffield

    2014-02-01

    Full Text Available The orchard crop pollinator Osmia lignaria (Hymenoptera: Megachilidae was evaluated for apple pollination in the Annapolis Valley, Nova Scotia, Canada during 2000-2001. Resulting pollination levels (measured as pollen grains on floral stigmas, percent fruit set, mature fruit weight and seed yield were evaluated against an attempted gradient of Osmia bee density. In addition, fruit quality was assessed using two symmetry indices, one based on fruit diameter, the second on fruit height. Pollination levels, percent fruit set and mature fruit quality were much higher than minimums required for adequate crop production, and all but pollination levels showed weak but significant decreases at increased distance from the established nests, suggesting that even at low numbers these bees may have been making significant contributions to apple production. Fruit were typically of better quality in areas of the orchard adjacent to Osmia nests, having fewer empty carpels and greater symmetry; fruit quality (i.e., symmetry is typically most reduced when two or more adjacent carpels are empty. Empty carpels reduce growth in fruit height rather than diameter, suggesting that symmetry indices using fruit diameter are not sensitive enough to evaluate fruit quality. Evidencing this, fruit without mature seeds observed in this study showed high symmetry based on diameter, but were greatly asymmetric with respect to fruit height. Further discussion on Osmia bees as apple pollinators and on methods of evaluating apple fruit quality with respect to seed distribution within the apple fruit are provided.

  5. An imputation/copula-based stochastic individual tree growth model for mixed species Acadian forests: a case study using the Nova Scotia permanent sample plot network

    Directory of Open Access Journals (Sweden)

    John A. KershawJr

    2017-09-01

    Full Text Available Background A novel approach to modelling individual tree growth dynamics is proposed. The approach combines multiple imputation and copula sampling to produce a stochastic individual tree growth and yield projection system. Methods The Nova Scotia, Canada permanent sample plot network is used as a case study to develop and test the modelling approach. Predictions from this model are compared to predictions from the Acadian variant of the Forest Vegetation Simulator, a widely used statistical individual tree growth and yield model. Results Diameter and height growth rates were predicted with error rates consistent with those produced using statistical models. Mortality and ingrowth error rates were higher than those observed for diameter and height, but also were within the bounds produced by traditional approaches for predicting these rates. Ingrowth species composition was very poorly predicted. The model was capable of reproducing a wide range of stand dynamic trajectories and in some cases reproduced trajectories that the statistical model was incapable of reproducing. Conclusions The model has potential to be used as a benchmarking tool for evaluating statistical and process models and may provide a mechanism to separate signal from noise and improve our ability to analyze and learn from large regional datasets that often have underlying flaws in sample design.

  6. Social vulnerability assessment of flood risk using GIS-based multicriteria decision analysis. A case study of Vila Nova de Gaia (Portugal

    Directory of Open Access Journals (Sweden)

    Paulo Fernandez

    2016-07-01

    Full Text Available Over the last decade, flood disasters have affected millions of people and caused massive economic losses. Social vulnerability assessment uses a combination of several factors to represent a population's differential access to resources and its ability to cope with and respond to hazards. In this paper, social vulnerability assessment to flood risk was applied to the third most populous Portuguese municipality. The study was developed at the neighbourhood level, allowing for social vulnerability analysis at inter civil parish, intra civil parish, and municipality scales. A geographic information system-based multicriteria decision analysis (GIS-MCDA was applied to social vulnerability and allows for an increased understanding and improved monitoring of social vulnerability over space, identifying ‘hot spots’ that require adaptation policies. Mafamude, Oliveira do Douro, Vila Nova de Gaia, and Avintes civil parishes display the greatest vulnerability to flooding. According to the most pessimistic scenario 57%–68% of the area of these civil parishes is classed at a high or very high level of social vulnerability. The GIS-MCDA helps to assess what and who is at risk, and where targeted impact-reduction strategies should be implemented. The results demonstrate the importance of an urban-scale approach instead of a river basin scale to urban flood risk management plans.

  7. (n,{gamma}) and (p,{gamma}) rates for s- and p-process nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kaeppeler, F [Forschungszentrum Karlsruhe, Karlsruhe (Germany)

    1998-06-01

    The late stages of stellar evolution are characterized by a series of nucleosynthesis events. With respect to the heavy elements, these are the s process associated with the helium burning layers in Red Giant stars as well as the r and p processes which occur in supernova explosions. In contrast to the explosive scenarios, the nuclear physics data for s-process studies can be determined in laboratory experiments as illustrated at few recent examples. The application of these techniques to measurements of relevance for the p process are also discussed. (orig.)

  8. (n,γ) and (p,γ) rates for s- and p-process nucleosynthesis

    International Nuclear Information System (INIS)

    Kaeppeler, F.

    1998-01-01

    The late stages of stellar evolution are characterized by a series of nucleosynthesis events. With respect to the heavy elements, these are the s process associated with the helium burning layers in Red Giant stars as well as the r and p processes which occur in supernova explosions. In contrast to the explosive scenarios, the nuclear physics data for s-process studies can be determined in laboratory experiments as illustrated at few recent examples. The application of these techniques to measurements of relevance for the p process are also discussed. (orig.)

  9. Revisiting big-bang nucleosynthesis constraints on dark-matter annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Kawasaki, Masahiro [Institute for Cosmic Ray Research, The University of Tokyo, Kashiwa 277-8582 (Japan); Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa 277-8583 (Japan); Kohri, Kazunori [Theory Center, IPNS, KEK, Tsukuba 305-0801 (Japan); Sokendai, Tsukuba 305-0801 (Japan); Moroi, Takeo [Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa 277-8583 (Japan); Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Takaesu, Yoshitaro, E-mail: takaesu@hep-th.phys.s.u-tokyo.ac.jp [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)

    2015-12-17

    We study the effects of dark-matter annihilation during the epoch of big-bang nucleosynthesis on the primordial abundances of light elements. We improve the calculation of the light-element abundances by taking into account the effects of anti-nucleons emitted by the annihilation of dark matter and the interconversion reactions of neutron and proton at inelastic scatterings of energetic nucleons. Comparing the theoretical prediction of the primordial light-element abundances with the latest observational constraints, we derive upper bounds on the dark-matter pair-annihilation cross section. Implication to some of particle-physics models are also discussed.

  10. Revisiting big-bang nucleosynthesis constraints on dark-matter annihilation

    Directory of Open Access Journals (Sweden)

    Masahiro Kawasaki

    2015-12-01

    Full Text Available We study the effects of dark-matter annihilation during the epoch of big-bang nucleosynthesis on the primordial abundances of light elements. We improve the calculation of the light-element abundances by taking into account the effects of anti-nucleons emitted by the annihilation of dark matter and the interconversion reactions of neutron and proton at inelastic scatterings of energetic nucleons. Comparing the theoretical prediction of the primordial light-element abundances with the latest observational constraints, we derive upper bounds on the dark-matter pair-annihilation cross section. Implication to some of particle-physics models are also discussed.

  11. Hadronic decay of late-decaying particles and big-bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kawasaki, Masahiro [Research Center for the Early Universe, Graduate School of Science, University of Tokyo, Tokyo 113-0033 (Japan)]. E-mail: masahiro_kawasaki@mac.com; Kohri, Kazunori [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Moroi, Takeo [Department of Physics, Tohoku University, Sendai 980-8578 (Japan)

    2005-10-06

    We study the big-bang nucleosynthesis (BBN) scenario with late-decaying exotic particles with lifetime longer than {approx}1 s. With a late-decaying particle in the early universe, predictions of the standard BBN scenario can be significantly altered. Therefore, we derive constraints on its primordial abundance. We pay particular attention to hadronic decay modes of such particles. We see that the non-thermal production process of D, {sup 3}He and {sup 6}Li provides a stringent upper bound on the primordial abundance of late-decaying particles with hadronic branching ratio.

  12. Nucleosynthesis in neutrino-driven winds: Influence of the nuclear physics input

    International Nuclear Information System (INIS)

    Arcones, Almudena; Martinez-Pinedo, Gabriel

    2010-01-01

    We have performed hydrodynamical simulations of the long-time evolution of proto-neutron stars to study the nucleosynthesis using the resulting wind trajectories. Although the conditions found in the present wind models are not favourable for the production of heavy elements, a small enhancement of the entropy results in the production of r-process elements with A ∼ 195. This allows us to explore the sensitivity of their production to the hydrodynamical evolution (wind termination shock) and nuclear physics input used.

  13. Efficacy and patient satisfaction after NovaSure and Minerva endometrial ablation for treating abnormal uterine bleeding: a retrospective comparative study.

    Science.gov (United States)

    Scordalakes, Constantine; delRosario, Robert; Shimer, Andrew; Stankiewicz, Russell

    2018-01-01

    Compare amenorrhea rate, menstrual symptoms, patient satisfaction, and adverse events in women who underwent endometrial ablation with the NovaSure versus the Minerva radiofrequency ablation systems. We surveyed 189 premenopausal women (mean 40.8±6.2 years old) who underwent endometrial ablation for abnormal uterine bleeding using the NovaSure (n=97) or Minerva (n=92) systems, at four private US gynecology clinics, and whose procedure date was after July 2015 with follow-up ≥3 months. Women were surveyed an average of 11.3±3.9 months (range 137-532 days) after ablation. The subject-reported amenorrhea rate was 52% higher in NovaSure subjects than Minerva subjects (64% and 42%, respectively; p =0.004). Age and bleeding cyclicity did not affect amenorrhea rate in either group. Normal-to-no bleeding was reported by >90% of subjects after either treatment. NovaSure was significantly more effective than Minerva at reducing pad/tampon use in women with any residual bleeding (2.4±5.2 items/day versus 4.7±5.5 items/day, p =0.049). NovaSure was significantly more effective than Minerva at reducing premenstrual syndrome (PMS) symptoms ( p =0.019) and menstrual pain ( p =0.003), and more NovaSure subjects (94%) than Minerva subjects (78%) were satisfied with clinical outcomes ( p =0.003). Adverse events did not differ by treatment; three women in each group progressed to hysterectomy. While overall bleeding reduction in premenopausal women with abnormal uterine bleeding was excellent with either endometrial ablation system, NovaSure treatment resulted in a higher patient-reported 1-year amenorrhea rate, and women with residual bleeding used fewer pads and tampons than Minerva-treated women. Additionally, NovaSure subjects reported better menstrual-related life quality and PMS symptom alleviation, and greater satisfaction with outcomes than Minerva-treated women.

  14. The assurance management program for the Nova laser fusion project

    International Nuclear Information System (INIS)

    Levy, A.J.

    1983-01-01

    In a well managed project, Quality Assurance is an integral part of the management activities performed on a daily basis. Management assures successful performance within budget and on schedule by using all the good business, scientific, engineering, quality assurance, and safety practices available. Quality assurance and safety practices employed on Nova are put in perspective by integrating them into the overall function of good project management. The Inertial Confinement Fusion (ICF) approach is explained in general terms. The laser ICF and magnetic fusion facilities are significantly different in that the laser system is used solely as a highly reliable energy source for performing plasma physics experiments related to fusion target development; by contrast, magnetic fusion facilities are themselves the experiments. The Nova project consists of a 10-beam, 74 cm aperture neodymium-glass laser experimental facility which is being constructed by the Lawrence Livermore National Laboratory (LLNL) for the U.S. Department of Energy. Nova has a total estimated cost of $176M and will become operational in the Fall of 1984. The Nova laser will be used as the high energy driver for studying the regime of ignition for ICF. The Nova assurance management program was developed using the quality assurance (QA) approach first implemented at LLNL in early 1978. The LLNL QA program is described as an introduction to the Nova assurance management program. The Nova system is described pictorially through the Nova configuration, subsystems and major components, interjecting the QA techniques which are being pragmatically used to assure the successful completion of the project

  15. SWIFT X-RAY OBSERVATIONS OF CLASSICAL NOVAE. II. THE SUPER SOFT SOURCE SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Greg J. [American Astronomical Society, 2000 Florida Avenue, NW, Suite 400, Washington, DC 20009-1231 (United States); Ness, Jan-Uwe [XMM-Newton Science Operations Centre, ESAC, Apartado 78, 28691 Villanueva de la Canada, Madrid (Spain); Osborne, J. P.; Page, K. L.; Evans, P. A.; Beardmore, A. P. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Walter, Frederick M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Andrew Helton, L. [SOFIA Science Center, USRA, NASA Ames Research Center, M.S. N211-3, Moffett Field, CA 94035 (United States); Woodward, Charles E. [Minnesota Institute of Astrophysics, 116 Church Street S.E., University of Minnesota, Minneapolis, MN 55455 (United States); Bode, Mike [Astrophysics Research Institute, Liverpool John Moores University, Birkenhead CH41 1LD (United Kingdom); Starrfield, Sumner [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287-1404 (United States); Drake, Jeremy J., E-mail: Greg.Schwarz@aas.org [Smithsonian Astrophysical Observatory, 60 Garden Street, MS 3, Cambridge, MA 02138 (United States)

    2011-12-01

    The Swift gamma-ray burst satellite is an excellent facility for studying novae. Its rapid response time and sensitive X-ray detector provides an unparalleled opportunity to investigate the previously poorly sampled evolution of novae in the X-ray regime. This paper presents Swift observations of 52 Galactic/Magellanic Cloud novae. We included the X-Ray Telescope (0.3-10 keV) instrument count rates and the UltraViolet and Optical Telescope (1700-8000 A) filter photometry. Also included in the analysis are the publicly available pointed observations of 10 additional novae the X-ray archives. This is the largest X-ray sample of Galactic/Magellanic Cloud novae yet assembled and consists of 26 novae with Super Soft X-ray emission, 19 from Swift observations. The data set shows that the faster novae have an early hard X-ray phase that is usually missing in slower novae. The Super Soft X-ray phase occurs earlier and does not last as long in fast novae compared to slower novae. All the Swift novae with sufficient observations show that novae are highly variable with rapid variability and different periodicities. In the majority of cases, nuclear burning ceases less than three years after the outburst begins. Previous relationships, such as the nuclear burning duration versus t{sub 2} or the expansion velocity of the eject and nuclear burning duration versus the orbital period, are shown to be poorly correlated with the full sample indicating that additional factors beyond the white dwarf mass and binary separation play important roles in the evolution of a nova outburst. Finally, we confirm two optical phenomena that are correlated with strong, soft X-ray emission which can be used to further increase the efficiency of X-ray campaigns.

  16. SWIFT X-RAY OBSERVATIONS OF CLASSICAL NOVAE. II. THE SUPER SOFT SOURCE SAMPLE

    International Nuclear Information System (INIS)

    Schwarz, Greg J.; Ness, Jan-Uwe; Osborne, J. P.; Page, K. L.; Evans, P. A.; Beardmore, A. P.; Walter, Frederick M.; Andrew Helton, L.; Woodward, Charles E.; Bode, Mike; Starrfield, Sumner; Drake, Jeremy J.

    2011-01-01

    The Swift gamma-ray burst satellite is an excellent facility for studying novae. Its rapid response time and sensitive X-ray detector provides an unparalleled opportunity to investigate the previously poorly sampled evolution of novae in the X-ray regime. This paper presents Swift observations of 52 Galactic/Magellanic Cloud novae. We included the X-Ray Telescope (0.3-10 keV) instrument count rates and the UltraViolet and Optical Telescope (1700-8000 Å) filter photometry. Also included in the analysis are the publicly available pointed observations of 10 additional novae the X-ray archives. This is the largest X-ray sample of Galactic/Magellanic Cloud novae yet assembled and consists of 26 novae with Super Soft X-ray emission, 19 from Swift observations. The data set shows that the faster novae have an early hard X-ray phase that is usually missing in slower novae. The Super Soft X-ray phase occurs earlier and does not last as long in fast novae compared to slower novae. All the Swift novae with sufficient observations show that novae are highly variable with rapid variability and different periodicities. In the majority of cases, nuclear burning ceases less than three years after the outburst begins. Previous relationships, such as the nuclear burning duration versus t 2 or the expansion velocity of the eject and nuclear burning duration versus the orbital period, are shown to be poorly correlated with the full sample indicating that additional factors beyond the white dwarf mass and binary separation play important roles in the evolution of a nova outburst. Finally, we confirm two optical phenomena that are correlated with strong, soft X-ray emission which can be used to further increase the efficiency of X-ray campaigns.

  17. Primordial and Stellar Nucleosynthesis Chemical Evolution of Galaxies

    International Nuclear Information System (INIS)

    Chiosi, Cesare

    2010-01-01

    Following a brief introduction to early Universe cosmology, we present in some detail the results of primordial nucleosynthesis. Then we summarize the basic theory of nuclear reactions in stars and sketch the general rules of stellar evolution. We shortly review the subject of supernova explosions both by core collapse in massive stars (Type II) and carbon-deflagration in binary systems when one of the components is a White Dwarf accreting mass from the companion (Type Ia). We conclude the part dedicated to nucleosynthesis with elementary notions on the s- and r-process. Finally, we shortly address the topic of galactic chemical evolution and highlight some simple solutions aimed at understanding the main observational data on abundances and abundance ratios.

  18. The standard and degenerate primordial nucleosynthesis versus recent experimental data

    International Nuclear Information System (INIS)

    Esposito, S.; Mangano, G.; Miele, G.; Pisanti, O.

    2000-01-01

    We report the results on Big Bang Nucleosynthesis (BBN) based on an updated code, with accuracy of the order of 0.1% on He4 abundance, compared with the predictions of other recent similar analysis. We discuss the compatibility of the theoretical results, for vanishing neutrino chemical potentials, with the observational data. Bounds on the number of relativistic neutrinos and baryon abundance are obtained by a likelihood analysis. We also analyze the effect of large neutrino chemical potentials on primordial nucleosynthesis, motivated by the recent results on the Cosmic Microwave Background Radiation spectrum. The BBN exclusion plots for electron neutrino chemical potential and the effective number of relativistic neutrinos are reported. We find that the standard BBN seems to be only marginally in agreement with the recent BOOMERANG and MAXIMA-1 results, while the agreement is much better for degenerate BBN scenarios for large effective number of neutrinos, N ν ∼ 10. (author)

  19. Particle Physics Catalysis of Thermal Big Bang Nucleosynthesis

    International Nuclear Information System (INIS)

    Pospelov, Maxim

    2007-01-01

    We point out that the existence of metastable, τ>10 3 s, negatively charged electroweak-scale particles (X - ) alters the predictions for lithium and other primordial elemental abundances for A>4 via the formation of bound states with nuclei during big bang nucleosynthesis. In particular, we show that the bound states of X - with helium, formed at temperatures of about T=10 8 K, lead to the catalytic enhancement of 6 Li production, which is 8 orders of magnitude more efficient than the standard channel. In particle physics models where subsequent decay of X - does not lead to large nonthermal big bang nucleosynthesis effects, this directly translates to the level of sensitivity to the number density of long-lived X - particles (τ>10 5 s) relative to entropy of n X - /s -17 , which is one of the most stringent probes of electroweak scale remnants known to date

  20. Particle physics catalysis of thermal big bang nucleosynthesis.

    Science.gov (United States)

    Pospelov, Maxim

    2007-06-08

    We point out that the existence of metastable, tau>10(3) s, negatively charged electroweak-scale particles (X-) alters the predictions for lithium and other primordial elemental abundances for A>4 via the formation of bound states with nuclei during big bang nucleosynthesis. In particular, we show that the bound states of X- with helium, formed at temperatures of about T=10(8) K, lead to the catalytic enhancement of 6Li production, which is 8 orders of magnitude more efficient than the standard channel. In particle physics models where subsequent decay of X- does not lead to large nonthermal big bang nucleosynthesis effects, this directly translates to the level of sensitivity to the number density of long-lived X- particles (tau>10(5) s) relative to entropy of nX-/s less, approximately <3x10(-17), which is one of the most stringent probes of electroweak scale remnants known to date.

  1. Dirac fields in loop quantum gravity and big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Bojowald, Martin; Das, Rupam; Scherrer, Robert J.

    2008-01-01

    Big bang nucleosynthesis requires a fine balance between equations of state for photons and relativistic fermions. Several corrections to equation of state parameters arise from classical and quantum physics, which are derived here from a canonical perspective. In particular, loop quantum gravity allows one to compute quantum gravity corrections for Maxwell and Dirac fields. Although the classical actions are very different, quantum corrections to the equation of state are remarkably similar. To lowest order, these corrections take the form of an overall expansion-dependent multiplicative factor in the total density. We use these results, along with the predictions of big bang nucleosynthesis, to place bounds on these corrections and especially the patch size of discrete quantum gravity states.

  2. Lepton asymmetry, neutrino spectral distortions, and big bang nucleosynthesis

    Science.gov (United States)

    Grohs, E.; Fuller, George M.; Kishimoto, C. T.; Paris, Mark W.

    2017-03-01

    We calculate Boltzmann neutrino energy transport with self-consistently coupled nuclear reactions through the weak-decoupling-nucleosynthesis epoch in an early universe with significant lepton numbers. We find that the presence of lepton asymmetry enhances processes which give rise to nonthermal neutrino spectral distortions. Our results reveal how asymmetries in energy and entropy density uniquely evolve for different transport processes and neutrino flavors. The enhanced distortions in the neutrino spectra alter the expected big bang nucleosynthesis light element abundance yields relative to those in the standard Fermi-Dirac neutrino distribution cases. These yields, sensitive to the shapes of the neutrino energy spectra, are also sensitive to the phasing of the growth of distortions and entropy flow with time/scale factor. We analyze these issues and speculate on new sensitivity limits of deuterium and helium to lepton number.

  3. Was the Universe actually radiation dominated prior to nucleosynthesis?

    Science.gov (United States)

    Giblin, John T.; Kane, Gordon; Nesbit, Eva; Watson, Scott; Zhao, Yue

    2017-08-01

    Maybe not. String theory approaches to both beyond the Standard Model and inflationary model building generically predict the existence of scalars (moduli) that are light compared to the scale of quantum gravity. These moduli become displaced from their low energy minima in the early Universe and lead to a prolonged matter-dominated epoch prior to big bang nucleosynthesis (BBN). In this paper, we examine whether nonperturbative effects such as parametric resonance or tachyonic instabilities can shorten, or even eliminate, the moduli condensate and matter-dominated epoch. Such effects depend crucially on the strength of the couplings, and we find that unless the moduli become strongly coupled, the matter-dominated epoch is unavoidable. In particular, we find that in string and M-theory compactifications where the lightest moduli are near the TeV scale, a matter-dominated epoch will persist until the time of big bang nucleosynthesis.

  4. Challenges to the standard model of Big Bang nucleosynthesis

    International Nuclear Information System (INIS)

    Steigman, G.

    1993-01-01

    Big Bang nucleosynthesis provides a unique probe of the early evolution of the Universe and a crucial test of the consistency of the standard hot Big Bang cosmological model. Although the primordial abundances of 2 H, 3 He, 4 He, and 7 Li inferred from current observational data are in agreement with those predicted by Big Bang nucleosynthesis, recent analysis has severely restricted the consistent range for the nucleon-to-photon ratio: 3.7 ≤ η 10 ≤ 4.0. Increased accuracy in the estimate of primordial 4 he and observations of Be and B in Pop II stars are offering new challenges to the standard model and suggest that no new light particles may be allowed (N ν BBN ≤ 3.0, where N ν is the number of equivalent light neutrinos). 23 refs

  5. Monte Carlo calculations for r-process nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Mumpower, Matthew Ryan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-12

    A Monte Carlo framework is developed for exploring the impact of nuclear model uncertainties on the formation of the heavy elements. Mass measurements tightly constrain the macroscopic sector of FRDM2012. For r-process nucleosynthesis, it is necessary to understand the microscopic physics of the nuclear model employed. A combined approach of measurements and a deeper understanding of the microphysics is thus warranted to elucidate the site of the r-process.

  6. Nucleosynthesis of heavy elements by the photonuclear reaction

    International Nuclear Information System (INIS)

    Hayakawa, Takehito

    2002-01-01

    Nucleosynthesis of heavy elements is important for understanding of the site mechanism in the stellar and cosmochronology. The nuclei heavier than iron have been synthesized mainly by the s-process and the β-decay after the r-process. The light isotope p-nuclei produced by the photonuclear reaction in Type II supernovae explosions. In order to understand the role of each process, the ratios of the processes are calculated. I propose the experimental plan using the photon sources. (author)

  7. Neutrinos and Nucleosynthesis in Hot and Dense Matter

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, George [Univ. of California, San Diego, CA (United States)

    2016-01-14

    The Topical Collaboration for Neutrinos and Nucleosynthesis in Hot and Dense matter brought together researchers from a variety of nuclear science specialties and a number of institutions to address nuclear physics and neutrino physics problems associated with dense matter and the origin of the elements. See attached final technical reports for (1) the UCSD award and (2) a copy of the report for the whole TC

  8. Possible evidence for dark radiation from Big Bang Nucleosynthesis data

    Energy Technology Data Exchange (ETDEWEB)

    Flambaum, V.V. [New South Wales Univ., School of Physics, Sydney NSW (Australia); Argonne National Laboratory, Physics Div., Argonne, IL (United States); Shuryak, E.V. [State University of New York Stony Brook, Dept. of Physics and Astronomy, NY (United States)

    2006-06-15

    We address the emerging discrepancy between the Big Bang Nucleosynthesis data and standard cosmology, which asks for a bit longer evolution time. If this effect is real, one possible implication (in a framework of brane cosmology model) is that there is a 'dark radiation' component which is negative and makes few percents of ordinary matter density. If so, all scales of this model can be fixed, provided brane-to-bulk leakage problem is solved. (authors)

  9. Possible evidence for dark radiation from Big Bang Nucleosynthesis data

    International Nuclear Information System (INIS)

    Flambaum, V.V.; Shuryak, E.V.

    2006-01-01

    We address the emerging discrepancy between the Big Bang Nucleosynthesis data and standard cosmology, which asks for a bit longer evolution time. If this effect is real, one possible implication (in a framework of brane cosmology model) is that there is a 'dark radiation' component which is negative and makes few percents of ordinary matter density. If so, all scales of this model can be fixed, provided brane-to-bulk leakage problem is solved. (authors)

  10. The gravitino-stau scenario after catalyzed big bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kersten, Joern [The Abdus Salam ICTP, Strada Costiera 11, 34014 Trieste (Italy); Schmidt-Hoberg, Kai, E-mail: jkersten@ictp.it, E-mail: kai.schmidt-hoberg@ph.tum.de, E-mail: kai.schmidt.hoberg@desy.de [Physik-Department T30, Technische Universitaet Muenchen, James-Franck-Strasse, 85748 Garching (Germany)

    2008-01-15

    We consider the impact of catalyzed big bang nucleosynthesis on theories with a gravitino lightest superparticle and a charged slepton next-to-lightest superparticle. In models where the gravitino to gaugino mass ratio is bounded from below, such as gaugino-mediated supersymmetry breaking, we derive a lower bound on the gaugino mass parameter m{sub 1/2}. As a concrete example, we determine the parameter space of gaugino mediation that is compatible with all cosmological constraints.

  11. The gravitino-stau scenario after catalyzed big bang nucleosynthesis

    Science.gov (United States)

    Kersten, Jörn; Schmidt-Hoberg, Kai

    2008-01-01

    We consider the impact of catalyzed big bang nucleosynthesis on theories with a gravitino lightest superparticle and a charged slepton next-to-lightest superparticle. In models where the gravitino to gaugino mass ratio is bounded from below, such as gaugino-mediated supersymmetry breaking, we derive a lower bound on the gaugino mass parameter m1/2. As a concrete example, we determine the parameter space of gaugino mediation that is compatible with all cosmological constraints.

  12. The gravitino–stau scenario after catalyzed big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Kersten, Jörn; Schmidt-Hoberg, Kai

    2008-01-01

    We consider the impact of catalyzed big bang nucleosynthesis on theories with a gravitino lightest superparticle and a charged slepton next-to-lightest superparticle. In models where the gravitino to gaugino mass ratio is bounded from below, such as gaugino-mediated supersymmetry breaking, we derive a lower bound on the gaugino mass parameter m 1/2 . As a concrete example, we determine the parameter space of gaugino mediation that is compatible with all cosmological constraints

  13. Nucleosynthesis and remnants in massive stars of solar metallicity

    International Nuclear Information System (INIS)

    Woosley, S.E.; Heger, A.

    2007-01-01

    Hans Bethe contributed in many ways to our understanding of the supernovae that happen in massive stars, but, to this day, a first principles model of how the explosion is energized is lacking. Nevertheless, a quantitative theory of nucleosynthesis is possible. We present a survey of the nucleosynthesis that occurs in 32 stars of solar metallicity in the mass range 12-120M sun . The most recent set of solar abundances, opacities, mass loss rates, and current estimates of nuclear reaction rates are employed. Restrictions on the mass cut and explosion energy of the supernovae based upon nucleosynthesis, measured neutron star masses, and light curves are discussed and applied. The nucleosynthetic results, when integrated over a Salpeter initial mass function (IMF), agree quite well with what is seen in the sun. We discuss in some detail the production of the long lived radioactivities, 26 Al and 60 Fe, and why recent model-based estimates of the ratio 60 Fe/ 26 Al are overly large compared with what satellites have observed. A major source of the discrepancy is the uncertain nuclear cross sections for the creation and destruction of these unstable isotopes

  14. Patient satisfaction and amenorrhea rate after endometrial ablation by ThermaChoice III or NovaSure: a retrospective cohort study

    NARCIS (Netherlands)

    Muller, I.; van der Palen, Jacobus Adrianus Maria; Massop-Helmink, D.; Vos-de Bruin, R.; Sikkema, J.M.

    2015-01-01

    Heavy menstrual bleeding poses an important health problem, which can be managed, besides other treatments, with endometrial ablation. Nowadays, the bipolar radio frequency device (NovaSure) is the most commonly used device for endometrial ablation, followed by the thermal balloon device

  15. Depressive symptoms are not associated with leukocyte telomere length: findings from the Nova Scotia Health Survey (NSHS95, a population-based study.

    Directory of Open Access Journals (Sweden)

    Jonathan A Shaffer

    Full Text Available Premature shortening of leukocyte telomere length has been proposed as a novel mechanism by which depression may confer increased risk of adverse cardiovascular events. Prior studies demonstrating associations of depression and depressive symptoms with shorter leukocyte telomere length were small, included selected psychiatric outpatients, were based on convenience samples, and/or adjusted for a limited number of possible confounding factors.We examined the associations of depressive symptoms, probable depressive disorder, and specific depressive symptom clusters, as assessed by the Center for Epidemiological Studies--Depression (CES-D scale, with leukocyte telomere length, measured by using a real-time PCR method, in 2,225 apparently healthy participants from the 1995 Nova Scotia Health Survey population-based study. The mean age was 48.2 ± 18.9 years; 49.9% of participants were female; and the mean CES-D score was 7.4 ± 7.9. The mean telomere length was 5,301 ± 587 base pairs. In an unadjusted model, depressive symptoms were significantly associated with longer leukocyte telomere length (B = 27.6 base pairs per standard deviation increase in CES-D, 95% confidence interval [CI] = 3.1-52.1, p = 0.027. This association was no longer significant after adjustment for age and sex (B = 9.5, 95% CI = -14.6-33.6, p = 0.44 or after further adjustment for body mass index, Framingham risk score and previous history of ischemic heart disease (all p's ≥ 0.37. Neither probable depressive disorder nor specific depressive symptom clusters were independently associated with leukocyte telomere length.Concurrent depressive symptoms were not associated with leukocyte telomere length in a large, representative, population-based study.

  16. The mass (charge) spectrum of superheavy nuclei fission fragments: the new perspectives for the theory of nucleosynthesis

    International Nuclear Information System (INIS)

    Maslyuk, V.T.

    2012-01-01

    A new approach to the problem of nucleosynthesis based on assumption of a nuclear matter or superheavy nuclei series fragmentation up to atomic nuclei is proposed. It is shown that studies of the mass (charge) fragments yields (MCFY) after nuclear matter disintegration is possible within proposed statistical theory. The data of MCFY calculation for exotic superheavy nuclei multifragmentation with A=300, 900 and 1200 and arbitrary Z values are demonstrated

  17. Photometry and polarimetry of Nova Andromedae 1986

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Sen; Mikami, Yoshitaka; Kondo, Masayuki

    1988-01-01

    We have carried out photometry of Nova Andromedae 1986 and find that it should be classified as a fast nova. We have also made polarimetry simultaneously at six wavelengths between 0.36-0.70 ..mu..m. The polarization increased between 2 and 22 days after the light maximum showing that dust formation was associated with the nova explosion.

  18. Observations of classical novae in outburst

    Science.gov (United States)

    Starrfield, S.; Stryker, L. L.; Sonneborn, G.; Sparks, Warren M.; Ferland, Gary; Wagner, R. M.; Williams, R. E.; Gehrz, Robert D.; Ney, Edward P.; Kenyon, Scott

    1988-01-01

    The IUE obtained ultraviolet data on novae in outburst. The characteristics of every one of the outbursts are different. Optical and infrared data on many of the same novae were also obtained. Three members of the carbon-oxygen class of novae are presented.

  19. 44Ti Nucleosynthesis Lines and Hard X-ray Continuum in Young SNRs: from INTEGRAL to Simbol-X

    Science.gov (United States)

    Renaud, M.; Terrier, R.; Trap, G.; Lebrun, F.; Decourchelle, A.; Vink, J.

    2009-05-01

    Supemovae and their remnants are the main Galactic nucleosynthesis sites and the privileged sources of Galactic cosmic rays. The youngest of such remnants can be studied through two distinct observational features: 44Ti γ-ray lines and the hard X-ray nonthermal continuum emission. The former gives unique information on the nucleosynthesis conditions occuring during the first stages of the explosion, while the latter provides clues on acceleration processes at supernova remnant shocks. In this contribution, we present new INTEGRAL results on Tycho, the remnant of a historical supernova, and on G1.9+0.3, which has been recently unveiled as the youngest Galactic supernova remnant. Expectations with Simbol-X are also addressed.

  20. 44Ti Nucleosynthesis Lines and Hard X-ray Continuum in Young SNRs: from INTEGRAL to Simbol-X

    International Nuclear Information System (INIS)

    Renaud, M.; Terrier, R.; Lebrun, F.; Trap, G.; Decourchelle, A.; Vink, J.

    2009-01-01

    Supemovae and their remnants are the main Galactic nucleosynthesis sites and the privileged sources of Galactic cosmic rays. The youngest of such remnants can be studied through two distinct observational features: 44 Tiγ-ray lines and the hard X-ray nonthermal continuum emission. The former gives unique information on the nucleosynthesis conditions occuring during the first stages of the explosion, while the latter provides clues on acceleration processes at supernova remnant shocks. In this contribution, we present new INTEGRAL results on Tycho, the remnant of a historical supernova, and on G1.9+0.3, which has been recently unveiled as the youngest Galactic supernova remnant. Expectations with Simbol-X are also addressed.

  1. Spectrophotometry of nova Cygni 1975

    International Nuclear Information System (INIS)

    Panek, R.J.

    1977-01-01

    Low-resolution spectrophotometry of nova Cygni 1975 is presented for eight nights in September 1975. Representative spectrum scans from 3600 A to 4500 A (10 A bandpass) and from 6350 A to 6750 A (20 A bandpass) also are shown

  2. Status for CASA NOVA konsortiet

    DEFF Research Database (Denmark)

    Bonke, Sten

    1997-01-01

    The report reviews the development projects and the results hitherto achieved by the design and build organisation CASA NOVA which is one of four consortia within the R&D programme "Process and Product Development in Building", financed by the Ministry of Industry and the Ministry of Housing....

  3. Theoretical and observational review of results on nova explosions occurring on ONeMg white dwarfs

    International Nuclear Information System (INIS)

    Starrfield, S.

    1986-01-01

    The nova outburst is the second most violent explosion that occurs in a galaxy. This review presents the recent observational and theoretical studies that have demonstrated that there exist two classes of nova outburst. One type of nova occurs on a CO white dwarf and the other type of nova occurs on an ONeMg white dwarf. The second class of outbursts are much more violent and occur much more frequently then the first class of outbursts. Hydrodynamic simulations of both kinds of outbursts are in excellent agreement with the observations. 51 refs

  4. Neutrino-Induced Nucleosynthesis in Helium Shells of Early Core-Collapse Supernovae

    Directory of Open Access Journals (Sweden)

    Banerjee Projjwal

    2016-01-01

    Full Text Available We summarize our studies on neutrino-driven nucleosynthesis in He shells of early core-collapse supernovae with metallicities of Z ≲ 10−3 Z⊙. We find that for progenitors of ∼ 11–15 M⊙, the neutrons released by 4He(ν¯ee, e+n3H in He shells can be captured to produce nuclei with mass numbers up to A ∼ 200. This mechanism is sensitive to neutrino emission spectra and flavor oscillations. In addition, we find two new primary mechanisms for neutrino-induced production of 9Be in He shells. The first mechanism produces 9Be via 7Li(n,γ8Li(n,γ9Li(e− ν¯ee9Be and relies on a low explosion energy for its survival. The second mechanism operates in progenitors of ∼ 8 M⊙, where 9Be can be produced directly via 7Li(3H, n09Be during the rapid expansion of the shocked Heshell material. The light nuclei 7Li and 3H involved in these mechanisms are produced by neutrino interactions with 4He. We discuss the implications of neutrino-induced nucleosynthesis in He shells for interpreting the elemental abundances in metal-poor stars.

  5. First measurement of the 34S(p ,γ )35Cl reaction rate through indirect methods for presolar nova grains

    Science.gov (United States)

    Gillespie, S. A.; Parikh, A.; Barton, C. J.; Faestermann, T.; José, J.; Hertenberger, R.; Wirth, H.-F.; de Séréville, N.; Riley, J. E.; Williams, M.

    2017-08-01

    Sulphur isotopic ratio measurements may help to establish the astrophysical sites in which certain presolar grains were formed. Nova model predictions of the 34S/32S ratio are, however, unreliable due to the lack of an experimental 34S(p ,γ )35Cl reaction rate. To this end, we have measured the 34S(3He,d )35Cl reaction at 20 MeV using a high resolution quadrupole-dipole-dipole-dipole magnetic spectrograph. Twenty-two levels over 6.2 MeV rate has been determined using a Monte Carlo method. Hydrodynamic nova model calculations have been performed using this new reaction rate. These models show that remaining uncertainties in the 34S(p ,γ ) rate affect nucleosynthesis predictions by less than a factor of 1.4, and predict a 34S/32S isotopic ratio of 0.014-0.017. Since recent type II supernova models predict 34S/32S=0.026 -0.053 , the 34S/32S isotopic ratio may be used, in conjunction with other isotopic signatures, to distinguish presolar grains from oxygen-neon nova and type II supernova origin. Our results address a key nuclear physics uncertainty on which recent considerations discounting the nova origin of several grains depend.

  6. Nova frequency conversion and focusing system

    International Nuclear Information System (INIS)

    Summers, M.A.; Seppala, L.G.; Williams, J.D.

    1985-01-01

    New developments in crystal array technology provided significant improvements in the mechanical design and optical performance of the Nova 2 omega/3 omega array hardware. The final Nova array configuration was tested on the Novette laser and on the first arm of Nova. Ten Nova 2 omega/3 omega crystal arrays were assembled and tested for crystal alignment and wave front distortion before installation on the Nova target chamber. Ten Nova focus lens positioners were assembled and tested last year. The positioning accuracy and repeatability of each assembly were evaluated before installation on the target chamber. A cylindrical focusing system was also developed for installation in the Nova lens positioner assembly. Finally, 10 completed frequency conversion and focusing systems were activated

  7. Study of a new glass matrix by the thermoluminescence technique; Estudo de uma nova matriz vitrea pela tecnica de termoluminescencia

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Pamela Z.; Vedovato, Uly P.; Cunha, Diego M. da; Dantas, Noelio O.; Silva, Anielle C.A.; Neves, Lucio P.; Perini, Ana P., E-mail: anapaula.perini@ufu.br [Universidade Federal de Uberlandia (INFIS/UFU), MG (Brazil). Instituto de Fisica; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Carrera, Betzabel N.S.; Watanabe, Shigueo [Universidade de Sao Paulo (IF/USP), Sao Paulo, SP (Brazil). Instituto de Fisica

    2015-07-01

    The thermoluminescence technique is widely used for both personal and for high-dose dosimetry. In this work, the thermoluminescence technique was utilized to study a new glass matrix, with nominal composition of 20Li{sub 2}CO{sub 3}.10Al{sub 2}O{sub 3}.20BaO.50B{sub 2}O{sub 3} (mol%), irradiated with different doses in a {sup 60}Co source. The glow curves and the dose-response curve were obtained for radiation doses between 50 Gy and 900 Gy. The results showed that this new glass matrix presents potential use in high-dose dosimetry. (author)

  8. Identifying and quantifying recurrent novae masquerading as classical novae

    International Nuclear Information System (INIS)

    Pagnotta, Ashley; Schaefer, Bradley E.

    2014-01-01

    Recurrent novae (RNe) are cataclysmic variables with two or more nova eruptions within a century. Classical novae (CNe) are similar systems with only one such eruption. Many of the so-called CNe are actually RNe for which only one eruption has been discovered. Since RNe are candidate Type Ia supernova progenitors, it is important to know whether there are enough in our Galaxy to provide the supernova rate, and therefore to know how many RNe are masquerading as CNe. To quantify this, we collected all available information on the light curves and spectra of a Galactic, time-limited sample of 237 CNe and the 10 known RNe, as well as exhaustive discovery efficiency records. We recognize RNe as having (1) outburst amplitude smaller than 14.5 – 4.5 × log (t 3 ), (2) orbital period >0.6 days, (3) infrared colors of J – H > 0.7 mag and H – K > 0.1 mag, (4) FWHM of Hα > 2000 km s –1 , (5) high excitation lines, such as Fe X or He II near peak, (6) eruption light curves with a plateau, and (7) white dwarf mass greater than 1.2 M ☉ . Using these criteria, we identify V1721 Aql, DE Cir, CP Cru, KT Eri, V838 Her, V2672 Oph, V4160 Sgr, V4643 Sgr, V4739 Sgr, and V477 Sct as strong RN candidates. We evaluate the RN fraction among the known CNe using three methods to get 24% ± 4%, 12% ± 3%, and 35% ± 3%. With roughly a quarter of the 394 known Galactic novae actually being RNe, there should be approximately a hundred such systems masquerading as CNe.

  9. AT Cnc: A SECOND DWARF NOVA WITH A CLASSICAL NOVA SHELL

    International Nuclear Information System (INIS)

    Shara, Michael M.; Mizusawa, Trisha; Zurek, David; Wehinger, Peter; Martin, Christopher D.; Neill, James D.; Forster, Karl; Seibert, Mark

    2012-01-01

    We are systematically surveying all known and suspected Z Cam-type dwarf novae for classical nova shells. This survey is motivated by the discovery of the largest known classical nova shell, which surrounds the archetypal dwarf nova Z Camelopardalis. The Z Cam shell demonstrates that at least some dwarf novae must have undergone classical nova eruptions in the past, and that at least some classical novae become dwarf novae long after their nova thermonuclear outbursts, in accord with the hibernation scenario of cataclysmic binaries. Here we report the detection of a fragmented 'shell', 3 arcmin in diameter, surrounding the dwarf nova AT Cancri. This second discovery demonstrates that nova shells surrounding Z Cam-type dwarf novae cannot be very rare. The shell geometry is suggestive of bipolar, conical ejection seen nearly pole-on. A spectrum of the brightest AT Cnc shell knot is similar to that of the ejecta of the classical nova GK Per, and of Z Cam, dominated by [N II] emission. Galaxy Evolution Explorer FUV imagery reveals a similar-sized, FUV-emitting shell. We determine a distance of 460 pc to AT Cnc, and an upper limit to its ejecta mass of ∼5 × 10 –5 M ☉ , typical of classical novae.

  10. AT Cnc: A SECOND DWARF NOVA WITH A CLASSICAL NOVA SHELL

    Energy Technology Data Exchange (ETDEWEB)

    Shara, Michael M.; Mizusawa, Trisha; Zurek, David [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192 (United States); Wehinger, Peter [Steward Observatory, the University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Martin, Christopher D.; Neill, James D.; Forster, Karl [Department of Physics, Math and Astronomy, California Institute of Technology, 1200 East California Boulevard, Mail Code 405-47, Pasadena, CA 91125 (United States); Seibert, Mark [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

    2012-10-20

    We are systematically surveying all known and suspected Z Cam-type dwarf novae for classical nova shells. This survey is motivated by the discovery of the largest known classical nova shell, which surrounds the archetypal dwarf nova Z Camelopardalis. The Z Cam shell demonstrates that at least some dwarf novae must have undergone classical nova eruptions in the past, and that at least some classical novae become dwarf novae long after their nova thermonuclear outbursts, in accord with the hibernation scenario of cataclysmic binaries. Here we report the detection of a fragmented 'shell', 3 arcmin in diameter, surrounding the dwarf nova AT Cancri. This second discovery demonstrates that nova shells surrounding Z Cam-type dwarf novae cannot be very rare. The shell geometry is suggestive of bipolar, conical ejection seen nearly pole-on. A spectrum of the brightest AT Cnc shell knot is similar to that of the ejecta of the classical nova GK Per, and of Z Cam, dominated by [N II] emission. Galaxy Evolution Explorer FUV imagery reveals a similar-sized, FUV-emitting shell. We determine a distance of 460 pc to AT Cnc, and an upper limit to its ejecta mass of {approx}5 Multiplication-Sign 10{sup -5} M {sub Sun }, typical of classical novae.

  11. Effect of Undiagnosed Deep Adenomyosis After Failed NovaSure Endometrial Ablation

    NARCIS (Netherlands)

    Mengerink, B.B.; Wurff, A.A. van der; Haar, J.F. ter; Rooij, I.A.L.M. van; Pijnenborg, J.M.

    2015-01-01

    STUDY OBJECTIVE: To determine the prevalence of adenomyosis and deep adenomyosis after NovaSure (Hologic Inc., Newark, DE) endometrial ablation in hysterectomy specimens after NovaSure endometrial ablation failure. DESIGN: Prospective observational study (Canadian Task Force classification II-2).

  12. Dirac cosmology and the onset of galactic nucleosynthesis

    International Nuclear Information System (INIS)

    Adams, P.J.; Canuto, V.

    1976-01-01

    Recently Browne and Berman determined the onset of nucleosynthesis of heavy elements in the galaxy to be about 18 billion years ago based on the weak decay of rhenium 187 to osmium 187. This age is appreciably larger than the 13 billion years determined from the uranium decay chains. It is also larger than the 16 billion year age of the Universe determined from the standard model by the latest values of the Hubble constant and deceleration parameter. This letter points out that this discrepancy is predicted by Dirac's cosmology and derives from a time-varying weak coupling constant. (Auth.)

  13. Coupled variations of fundamental couplings and primordial nucleosynthesis

    International Nuclear Information System (INIS)

    Coc, Alain; Nunes, Nelson J.; Olive, Keith A.; Uzan, Jean-Philippe; Vangioni, Elisabeth

    2006-10-01

    The effect of variations of the fundamental nuclear parameters on big-bang nucleosynthesis are modeled and discussed in detail taking into account the interrelations between the fundamental parameters arising in unified theories. Considering only 4 He, strong constraints on the variation of the neutron lifetime, neutron-proton mass difference are set. These constraints are then translated into constraints on the time variation of the Yukawa couplings and the fine structure constant. Furthermore, we show that a variation of the deuterium binding energy is able to reconcile the 7 Li abundance deduced from the WMAP analysis with its spectroscopically determined value while maintaining concordance with D and 4 He. (authors)

  14. Big bang photosynthesis and pregalactic nucleosynthesis of light elements

    International Nuclear Information System (INIS)

    Audouze, J.; Lindley, D.; Silk, J.; and Laboratoire Rene Bernas, Orsay, France)

    1985-01-01

    Two nonstandard scenarios for pregalactic synthesis of the light elements ( 2 H, 3 He, 4 He, and 7 Li) are developed. Big bang photosynthesis occurs if energetic photons, produced by the decay of massive neutrinos or gravitinos, partially photodisintegrate 4 He (formed in the standard hot big bang) to produce 2 H and 3 He. In this case, primordial nucleosynthesis no longer constrains the baryon density of the universe, or the number of neutrino species. Alternatively, one may dispense partially or completely with the hot big bang and produce the light elements by bombardment of primordial gas, provided that 4 He is synthesized by a later generation of massive stars

  15. Big bang photosynthesis and pregalactic nucleosynthesis of light elements

    Science.gov (United States)

    Audouze, J.; Lindley, D.; Silk, J.

    1985-01-01

    Two nonstandard scenarios for pregalactic synthesis of the light elements (H-2, He-3, He-4, and Li-7) are developed. Big bang photosynthesis occurs if energetic photons, produced by the decay of massive neutrinos or gravitinos, partially photodisintegrate He-4 (formed in the standard hot big bang) to produce H-2 and He-3. In this case, primordial nucleosynthesis no longer constrains the baryon density of the universe, or the number of neutrino species. Alternatively, one may dispense partially or completely with the hot big bang and produce the light elements by bombardment of primordial gas, provided that He-4 is synthesized by a later generation of massive stars.

  16. Capture reactions on C-14 in nonstandard big bang nucleosynthesis

    Science.gov (United States)

    Wiescher, Michael; Gorres, Joachim; Thielemann, Friedrich-Karl

    1990-01-01

    Nonstandard big bang nucleosynthesis leads to the production of C-14. The further reaction path depends on the depletion of C-14 by either photon, alpha, or neutron capture reactions. The nucleus C-14 is of particular importance in these scenarios because it forms a bottleneck for the production of heavier nuclei A greater than 14. The reaction rates of all three capture reactions at big bang conditions are discussed, and it is shown that the resulting reaction path, leading to the production of heavier elements, is dominated by the (p, gamma) and (n, gamma) rates, contrary to earlier suggestions.

  17. Collective neutrino oscillations and r-process nucleosynthesis in supernovae

    Science.gov (United States)

    Duan, Huaiyu

    2012-10-01

    Neutrinos can oscillate collectively in a core-collapse supernova. This phenomenon can occur much deeper inside the supernova envelope than what is predicted from the conventional matter-induced Mikheyev-Smirnov-Wolfenstein effect, and hence may have an impact on nucleosynthesis. The oscillation patterns and the r-process yields are sensitive to the details of the emitted neutrino fluxes, the sign of the neutrino mass hierarchy, the modeling of neutrino oscillations and the astrophysical conditions. The effects of collective neutrino oscillations on the r-process will be illustrated using representative late-time neutrino spectra and outflow models.

  18. Chiral-symmetry order parameter, the lattice, and nucleosynthesis

    International Nuclear Information System (INIS)

    McLerran, L.

    1987-01-01

    I discuss an order parameter for the chiral-symmetry restoration phase transition which may be useful in computations of big-bang nucleosynthesis, a phenomenon which requires a finite baryon-number density. This parameter is strictly speaking an order parameter in the large-N limit, and distinguishes between a parity-doubled and a massless-fermion realization of chiral-symmetry restoration. This order parameter may be evaluated at a zero net baryon-number density at finite temperature, and is useful as long as the baryon chemical potential μ is much less than the temperature T

  19. Constraining axion dark matter with Big Bang Nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Blum, Kfir; D' Agnolo, Raffaele Tito [Institute for Advanced Study, Princeton, NJ 08540 (United States); Lisanti, Mariangela; Safdi, Benjamin R. [Department of Physics, Princeton University, Princeton, NJ 08544 (United States)

    2014-10-07

    We show that Big Bang Nucleosynthesis (BBN) significantly constrains axion-like dark matter. The axion acts like an oscillating QCD θ angle that redshifts in the early Universe, increasing the neutron–proton mass difference at neutron freeze-out. An axion-like particle that couples too strongly to QCD results in the underproduction of {sup 4}He during BBN and is thus excluded. The BBN bound overlaps with much of the parameter space that would be covered by proposed searches for a time-varying neutron EDM. The QCD axion does not couple strongly enough to affect BBN.

  20. Constraining axion dark matter with Big Bang Nucleosynthesis

    Directory of Open Access Journals (Sweden)

    Kfir Blum

    2014-10-01

    Full Text Available We show that Big Bang Nucleosynthesis (BBN significantly constrains axion-like dark matter. The axion acts like an oscillating QCD θ angle that redshifts in the early Universe, increasing the neutron–proton mass difference at neutron freeze-out. An axion-like particle that couples too strongly to QCD results in the underproduction of He4 during BBN and is thus excluded. The BBN bound overlaps with much of the parameter space that would be covered by proposed searches for a time-varying neutron EDM. The QCD axion does not couple strongly enough to affect BBN.

  1. Constraining axion dark matter with Big Bang Nucleosynthesis

    International Nuclear Information System (INIS)

    Blum, Kfir; D'Agnolo, Raffaele Tito; Lisanti, Mariangela; Safdi, Benjamin R.

    2014-01-01

    We show that Big Bang Nucleosynthesis (BBN) significantly constrains axion-like dark matter. The axion acts like an oscillating QCD θ angle that redshifts in the early Universe, increasing the neutron–proton mass difference at neutron freeze-out. An axion-like particle that couples too strongly to QCD results in the underproduction of 4 He during BBN and is thus excluded. The BBN bound overlaps with much of the parameter space that would be covered by proposed searches for a time-varying neutron EDM. The QCD axion does not couple strongly enough to affect BBN

  2. Constraining axion dark matter with Big Bang Nucleosynthesis

    Science.gov (United States)

    Blum, Kfir; D'Agnolo, Raffaele Tito; Lisanti, Mariangela; Safdi, Benjamin R.

    2014-10-01

    We show that Big Bang Nucleosynthesis (BBN) significantly constrains axion-like dark matter. The axion acts like an oscillating QCD θ angle that redshifts in the early Universe, increasing the neutron-proton mass difference at neutron freeze-out. An axion-like particle that couples too strongly to QCD results in the underproduction of 4He during BBN and is thus excluded. The BBN bound overlaps with much of the parameter space that would be covered by proposed searches for a time-varying neutron EDM. The QCD axion does not couple strongly enough to affect BBN.

  3. BIG BANG NUCLEOSYNTHESIS WITH A NON-MAXWELLIAN DISTRIBUTION

    International Nuclear Information System (INIS)

    Bertulani, C. A.; Fuqua, J.; Hussein, M. S.

    2013-01-01

    The abundances of light elements based on the big bang nucleosynthesis model are calculated using the Tsallis non-extensive statistics. The impact of the variation of the non-extensive parameter q from the unity value is compared to observations and to the abundance yields from the standard big bang model. We find large differences between the reaction rates and the abundance of light elements calculated with the extensive and the non-extensive statistics. We found that the observations are consistent with a non-extensive parameter q = 1 - 0.12 +0.05 , indicating that a large deviation from the Boltzmann-Gibbs statistics (q = 1) is highly unlikely.

  4. Nova target diagnostics control system

    International Nuclear Information System (INIS)

    Severyn, J.R.

    1985-01-01

    During the past year the Nova target diagnostics control system was finished and put in service. The diagnostics loft constructed to the north of the target room provides the environmental conditions required to collect reliable target diagnostic data. These improvements include equipment cooling and isolation of the power source with strict control of instrumentation grounds to eliminate data corruption due to electromagnetic pulses from the laser power-conditioning system or from target implosion effects

  5. Constraining Calcium Production in Novae

    Science.gov (United States)

    Tiwari, Pranjal; C. Fry, C. Wrede Team; A. Chen, J. Liang Collaboration; S. Bishop, T. Faestermann, D. Seiler Collaboration; R. Hertenberger, H. Wirth Collaboration

    2017-09-01

    Calcium is an element that can be produced by thermonuclear reactions in the hottest classical novae. There are discrepancies between the abundance of Calcium observed in novae and expectations based on astrophysical models. Unbound states 1 MeV above the proton threshold affect the production of Calcium in nova models because they act as resonances in the 38 K(p , γ) 39 Ca reaction present. This work describes an experiment to measure the energies of the excited states of 39 Ca . We will bombard a thin target of 40 Ca with a beam of 22 MeV deuterons, resulting in tritons and 39Ca. We will use a Q3D magnetic spectrograph from the MLL in Garching, Germany to momenta analyze the tritons to observe the excitation energies of the resulting 39 Ca states. Simulations have been run to determine the optimal spectrograph settings. We decided to use a chemically stable target composed of CaF2 , doing so resulted in an extra contaminant, Fluorine, which is dealt with by measuring the background from a LiF target. These simulations have led to settings and targets that will result in the observation of the 39 Ca states of interest with minimal interference from contaminants. Preliminary results from this experiment will be presented. National Sciences and Engineering Research Council of Canada and U.S. National Science Foundation.

  6. Nova chain design and performance

    International Nuclear Information System (INIS)

    Simmons, W.W.; Glaze, J.A.; Trenholme, J.B.; Hagen, W.F.

    1980-01-01

    During the past year design of the Nova laser has undergone significant change as a result of developments in our laser glass and optical coating evaluation programs. Two notable aspects of the glass development program deserve emphasis. First, vendor qualification for production of fluorophosphate laser glass is progressing satisfactorily. There is a reasonable expectation that vendors can meet fluorophosphate glass specifications within Nova schedule constraints. Secondly, recent gain saturation measurements have shown that the saturation fluence of the fluorophosphate glass is larger than previously supposed (approx. 5.5 J/cm 2 ) and in fact is somewhat larger than Shiva silicate glasses. Hence, performance of Nova for pulses in the 3 ns and longer range should be satisfactory. For pulses in the 1 ns regime, of course, the fluorophosphate chain will have superior performance to that of silicate because of its low nonlinear index of refraction (approx. 30% that of silicate). These and other considerations have led us to choose a chain design based upon the use of fluorophosphate glass in our amplifiers

  7. Energy distributions of symbiotic novae

    International Nuclear Information System (INIS)

    Bryan, G.L.; Kwok, S.

    1991-01-01

    The IRAS low-resolution spectra of three recent symbiotic novae are fitted with a dust continuum radiative transfer model. It is found that the dust shells are detached from the photosphere and that the sizes of the inner radii are correlated with times since outburst. An analysis of the IUE spectra of HM Sge at different epochs suggests that the strength of the 2200 A feature is decreasing with times and the grains responsible for the feature are probably formed in the white dwarf ejecta. A complete accounting of the entire energy budget from radio to X-ray shows that most of the energy is emitted by the cool component in the infrared, and a significant fraction of the flux of the hot component is escaping in the far-ultraviolet. The density-bounded nature of the circumstellar gas nebulae could be the result of a bipolar geometry of the nebulae. Unlike classical novae, the optical outburst of symbiotic novae is due to the ionization of the preexisting envelope of the cool component and is not the result of a sudden ejection by the hot component. 55 refs

  8. Chemical evolution, stellar nucleosynthesis and a variable star formation rate

    International Nuclear Information System (INIS)

    Olive, K.A.; Thielemann, F.K.; Truran, J.W.

    1986-04-01

    The effects of a decreasing star formation rate (SFR) on the galactic abundances of elements produced in massive stars (M ≥ 10 Msub solar). On the basis of a straightforward model of galactic evolution, a relation between the upper mass limit of type II supernovae (M/sub SN/) contributing to chemical evolution and the decline of the SFR (tau) is derived, when the oxygen abundance is determined only by massive stars. The additional requirement that all intermediate mass elements (Ne-Ti), which are also predominantly due to nucleosynthesis in massive stars, are produced in solar proportions leads to a unique value of M/sub SN/ and tau. The application of this method with abundance yields from Arnett (1978) and Woosley and Weaver (1986) resuults, however, in contradicting solutions: M/sub SN/ ≅ 45 Msub solar, tau = ∞, and M/sub SN/ ≅ 15 Msub solar, tau = 3 x 10 9 y. Thus, in order that this approach provide an effective probe of the SFR over the history of our galaxy it is essential that converging and more accurate predictions of the consequences of stellar and supernova nucleosynthesis will be forthcoming. 54 refs., 2 figs., 2 tabs

  9. Big-bang nucleosynthesis in the new cosmology

    International Nuclear Information System (INIS)

    Fields, B.D.

    2005-01-01

    Big bang nucleosynthesis (BBN) describes the production of the lightest elements in the first minutes of cosmic time. I will review the physics of cosmological element production, and the observations of the primordial element abundances. The comparison between theory and observation has heretofore provided our earliest probe of the universe, and given the best measure of the cosmic baryon content. However, BBN has now taken a new role in cosmology, in light of new precision measurements of the cosmic microwave background (CMB). Recent CMB anisotropy data yield a wealth of cosmological parameters; in particular, the baryon-to-photon ratio η = n B /n γ is measured to high precision. The confrontation between the BBN and CMB 'baryometers' poses a new and stringent test of the standard cosmology; the status of this test will be discussed. Moreover, it is now possible to recast the role of BBN by using the CMB to fix the baryon density and even some light element abundances. This strategy sharpens BBN into a more powerful probe of early universe physics, and of galactic nucleosynthesis processes. The impact of the CMB results on particle physics beyond the Standard Model, and on non-standard cosmology, will be illustrated. Prospects for improvement of these bounds via additional astronomical observations and nuclear experiments will be discussed, as will the lingering 'lithium problem.' (author)

  10. First Neutrino Oscillation Results from the NOvA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sachdev, Kanika [Fermilab

    2016-11-29

    NOvA is a long-baseline neutrino oscillation experiment on the NuMI muon neutrino beam at Fermilab. It consists of two functionally identical, nearly fully-active liquid-scintillator tracking calorimeters. The Near Detector (ND) at Fermilab is used to study the neutrino beam spectrum and composition before oscillations occur. The Far Detector in northern Minnesota, 810 km away, observes the oscillated beam and is used to extract the oscillation parameters. NOvA is designed to observe oscillations in two channels: disappearance channel ( ν μ → ν μ ) and ν e appearance channel ( ν μ → ν e ). This paper reports the measurements of both these channels based on the first NOvA data taken from February 16, 2014 till May 15, 2015

  11. The geographic accessibility of pharmacies in Nova Scotia.

    Science.gov (United States)

    Law, Michael R; Heard, Deborah; Fisher, Judith; Douillard, Jay; Muzika, Greg; Sketris, Ingrid S

    2013-01-01

    Geographic proximity is an important component of access to primary care and the pharmaceutical services of community pharmacies. Variations in access to primary care have been found between rural and urban areas in Canadian and international jurisdictions. We studied access to community pharmacies in the province of Nova Scotia. We used information on the locations of 297 community pharmacies operating in Nova Scotia in June 2011. Population estimates at the census block level and network analysis were used to study the number of Nova Scotia residents living within 800 m (walking) and 2 km and 5 km (driving) distances of a pharmacy. We then simulated the impact of pharmacy closures on geographic access in urban and rural areas. We found that 40.3% of Nova Scotia residents lived within walking distance of a pharmacy; 62.6% and 78.8% lived within 2 km and 5 km, respectively. Differences between urban and rural areas were pronounced: 99.2% of urban residents lived within 5 km of a pharmacy compared with 53.3% of rural residents. Simulated pharmacy closures had a greater impact on geographic access to community pharmacies in rural areas than urban areas. The majority of Nova Scotia residents lived within walking or short driving distance of at least 1 community pharmacy. While overall geographic access appears to be lower than in the province of Ontario, the difference appears to be largely driven by the higher proportion of rural dwellers in Nova Scotia. Further studies should examine how geographic proximity to pharmacies influences patients' access to traditional and specialized pharmacy services, as well as health outcomes and adherence to therapy. Can Pharm J 2013;146:39-46.

  12. Analysis of the Nova Stat Strip® Glucose Meter for Real-Time Blood Glucose Determinations During Glucose Clamp Studies: “Don't Swap Horses in Midstream”

    Science.gov (United States)

    Heinemann, Lutz

    2010-01-01

    Proper performance of glucose clamps is critically dependent on reliable blood glucose (BG) measurements. A number of requirements have to be fulfilled by a system that aims to replace the laboratory devices that are currently in use. Many more aspects need to be taken into account besides the accuracy of BG measurement. It might very well be that the BG meter studied by Rabiee and colleagues in this issue of Journal of Diabetes Science and Technology fulfills most or all of such requirements; however, these aspects have to be tested more thoroughly before one switches from an established measurement method to the Nova Stat Strip® glucometer. PMID:20920441

  13. NITROGEN ISOTOPES IN ASYMPTOTIC GIANT BRANCH CARBON STARS AND PRESOLAR SiC GRAINS: A CHALLENGE FOR STELLAR NUCLEOSYNTHESIS

    International Nuclear Information System (INIS)

    Hedrosa, R. P.; Abia, C.; Domínguez, I.; Palmerini, S.; Busso, M.; Cristallo, S.; Straniero, O.; Plez, B.

    2013-01-01

    Isotopic ratios of C, N, Si, and trace heavy elements in presolar SiC grains from meteorites provide crucial constraints to nucleosynthesis. A long-debated issue is the origin of the so-called A+B grains, as of yet no stellar progenitor thus far has been clearly identified on observational grounds. We report the first spectroscopic measurements of 14 N/ 15 N ratios in Galactic carbon stars of different spectral types and show that J- and some SC-type stars might produce A+B grains, even for 15 N enrichments previously attributed to novae. We also show that most mainstream grains are compatible with the composition of N-type stars, but in some cases might also descend from SC stars. From a theoretical point of view, no astrophysical scenario can explain the C and N isotopic ratios of SC-, J-, and N-type carbon stars together, as well as those of many grains produced by them. This poses urgent questions to stellar physics.

  14. A new long-term care facilities model in nova scotia, Canada: protocol for a mixed methods study of care by design.

    Science.gov (United States)

    Marshall, Emily Gard; Boudreau, Michelle Anne; Jensen, Jan L; Edgecombe, Nancy; Clarke, Barry; Burge, Frederick; Archibald, Greg; Taylor, Anthony; Andrew, Melissa K

    2013-11-29

    Prior to the implementation of a new model of care in long-term care facilities in the Capital District Health Authority, Halifax, Nova Scotia, residents entering long-term care were responsible for finding their own family physician. As a result, care was provided by many family physicians responsible for a few residents leading to care coordination and continuity challenges. In 2009, Capital District Health Authority (CDHA) implemented a new model of long-term care called "Care by Design" which includes: a dedicated family physician per floor, 24/7 on-call physician coverage, implementation of a standardized geriatric assessment tool, and an interdisciplinary team approach to care. In addition, a new Emergency Health Services program was implemented shortly after, in which specially trained paramedics dedicated to long-term care responses are able to address urgent care needs. These changes were implemented to improve primary and emergency care for vulnerable residents. Here we describe a comprehensive mixed methods research study designed to assess the impact of these programs on care delivery and resident outcomes. The results of this research will be important to guide primary care policy for long-term care. We aim to evaluate the impact of introducing a new model of a dedicated primary care physician and team approach to long-term care facilities in the CDHA using a mixed methods approach. As a mixed methods study, the quantitative and qualitative data findings will inform each other. Quantitatively we will measure a number of indicators of care in CDHA long-term care facilities pre and post-implementation of the new model. In the qualitative phase of the study we will explore the experience under the new model from the perspectives of stakeholders including family doctors, nurses, administration and staff as well as residents and family members. The proposed mixed method study seeks to evaluate and make policy recommendations related to primary care in long

  15. Absolute spectrophotometry of Nova Cygni 1975

    International Nuclear Information System (INIS)

    Kontizas, E.; Kontizas, M.; Smyth, M.J.

    1976-01-01

    Radiometric photoelectric spectrophotometry of Nova Cygni 1975 was carried out on 1975 August 31, September 2, 3. α Lyr was used as reference star and its absolute spectral energy distribution was used to reduce the spectrophotometry of the nova to absolute units. Emission strengths of Hα, Hβ, Hγ (in W cm -2 ) were derived. The Balmer decrement Hα:Hβ:Hγ was compared with theory, and found to deviate less than had been reported for an earlier nova. (author)

  16. Searching for nova shells around cataclysmic variables

    Science.gov (United States)

    Sahman, D. I.; Dhillon, V. S.; Knigge, C.; Marsh, T. R.

    2015-08-01

    We present the results of a search for nova shells around 101 cataclysmic variables (CVs), using H α images taken with the 4.2-m William Herschel Telescope (WHT) and the 2.5-m Isaac Newton Telescope Photometric H α Survey of the Northern Galactic Plane (IPHAS). Both telescopes are located on La Palma. We concentrated our WHT search on nova-like variables, whilst our IPHAS search covered all CVs in the IPHAS footprint. We found one shell out of the 24 nova-like variables we examined. The newly discovered shell is around V1315 Aql and has a radius of ˜2.5 arcmin, indicative of a nova eruption approximately 120 yr ago. This result is consistent with the idea that the high mass-transfer rate exhibited by nova-like variables is due to enhanced irradiation of the secondary by the hot white dwarf following a recent nova eruption. The implications of our observations for the lifetime of the nova-like variable phase are discussed. We also examined four asynchronous polars, but found no new shells around any of them, so we are unable to confirm that a recent nova eruption is the cause of the asynchronicity in the white dwarf spin. We find tentative evidence of a faint shell around the dwarf nova V1363 Cyg. In addition, we find evidence for a light echo around the nova V2275 Cyg, which erupted in 2001, indicative of an earlier nova eruption ˜300 yr ago, making V2275 Cyg a possible recurrent nova.

  17. A statistical analysis of IUE spectra of dwarf novae and nova-like stars

    Science.gov (United States)

    Ladous, Constanze

    1990-01-01

    First results of a statistical analysis of the IUE International Ultraviolet Explorer archive on dwarf novae and nova like stars are presented. The archive contains approximately 2000 low resolution spectra of somewhat over 100 dwarf novae and nova like stars. Many of these were looked at individually, but so far the collective information content of this set of data has not been explored. The first results of work are reported.

  18. Uma nova forma de Coffea

    Directory of Open Access Journals (Sweden)

    C. A. Krug

    1950-01-01

    Full Text Available Nos extensos trabalhos de melhoramento do cafeeiro, há 18 anos em realização na Subdivisão de Genética do Instituto Agronômico, tem-se dedicado especial atenção à espécie C. arabica L., pelo fato de todos os nossos cafèzais pertencerem a esta espécie que, sem dúvida, fornece o produto de melhor qualidade. Nas regiões de terras extremamente cansadas, um dos principais fatôres levados em consideração no melhoramento é a rusticidade, caráter êsse, entretanto, encontrado de preferência em outras espécies, tais como o C. canephora e C. Dewevrei, cujos cafés são de má qualidade. A hibridação interespecífica, que poderia reunir em uma só planta caraterísticos de rusticidade e boa qualidade de bebida, tem o inconveniente de dar origem a plantas triplóides, que são estéreis. Daí se deduz que a obtenção artificial de formas que combinassem êsses caraterísticos constitui problema, cuja solução é extremamente demorada. No presente trabalho, apresentam-se os caracteres de uma nova forma de Coffea, encontrada em cafèzal da Fazenda Itaporã, em Terra Roxa, município de Viradouro, que, com algumas ressalvas, oferece a desejada combinação de caracteres. Trata-se, provàvelmente, de um híbrido espontâneo entre C. arabica e C. Dewevrei, com 2n = 44 cromosômios, extremamente rústico e produtivo, cujas sementes fornecem uma bebida que pode ser classificada como boa. Apenas apresenta, como principal defeito, uma auto-esterilidade quase completa. Os seus caraterísticos botânicos são descritos em detalhe. Devido ao seu porte elevado, ramos abundantes e folhas grandes e coriáceas, esse cafeeiro se assemelha ao C. Dewevrei. Os frutos são oval-elípticos, de um vermelho bem escuro quando maduros, e as sementes oblongas, constatan-do-se elevada percentagem do tipo "moca" e "chocha". Quanto à constituição citológica, as pesquisas conduziram à hipótese de este cafeeiro possuir 22 cromosômios de C. arabica e 22 (n

  19. Effects of sterile neutrino and extra-dimension on big bang nucleosynthesis

    Science.gov (United States)

    Jang, Dukjae; Kusakabe, Motohiko; Cheoun, Myung-Ki

    2018-04-01

    We study effects of the sterile neutrino in the five-dimensional universe on the big bang nucleosynthesis (BBN). Since the five-dimensional universe model leads to an additional term in the Friedmann equation and the energy density of the sterile neutrino increases the total energy density, this model can affect the primordial abundance via changing the cosmic expansion rate. The energy density of the sterile neutrino can be determined by a rate equation for production of the sterile neutrino. We show that not only the mixing angle and the mass of the sterile neutrino, but also a resonant effect in the oscillation between sterile and active neutrinos is important to determine a relic abundance of the sterile neutrino. In this study, we also investigate how the sterile neutrino in extra-dimensional model can affect the BBN, and constrain the parameters related to the above properties of the sterile neutrino by using the observational primordial abundances of light elements.

  20. Revisiting big-bang nucleosynthesis constraints on long-lived decaying particles

    Science.gov (United States)

    Kawasaki, Masahiro; Kohri, Kazunori; Moroi, Takeo; Takaesu, Yoshitaro

    2018-01-01

    We study the effects of long-lived massive particles, which decayed during the big-bang nucleosynthesis (BBN) epoch, on the primordial abundance of light elements. Compared to previous studies, (i) the reaction rates of standard BBN reactions are updated, (ii) the most recent observational data on the light element abundance and cosmological parameters are used, (iii) the effects of the interconversion of energetic nucleons at the time of inelastic scattering with background nuclei are considered, and (iv) the effects of the hadronic shower induced by energetic high-energy antinucleons are included. We compare the theoretical predictions on the primordial abundance of light elements with the latest observational constraints, and we derive upper bounds on the relic abundance of the decaying particle as a function of its lifetime. We also apply our analysis to an unstable gravitino, the superpartner of a graviton in supersymmetric theories, and obtain constraints on the reheating temperature after inflation.

  1. Baryonic density of the universe: Big Bang nucleosynthesis versus CMB observations

    International Nuclear Information System (INIS)

    Vangioni-Flam, E.; Coc, A.; Casse, M.

    2003-01-01

    Thanks to recent nuclear reaction rate compilations (NACRE[2]) and new experimental and theoretical works in nuclear physics, we have updated Standard Big Bang Nucleosynthesis (SBBN) calculations. The results are compared to the most representative light element abundances, measured in pristine astrophysical media to derive the baryonic density of the Universe. We confront Ω b h 2 obtained in this study with other values deduced from recent independent approaches as the observations of the anisotropies of the Cosmic Microwave Background (BOOMERANG, CBI, DASI, MAXIMA and VSA experiments) or the Lyman-α forest at high redshifts. Comparison between these results is a test of their consistency and could provide a better determination of this important cosmological parameter

  2. Constraining f(T) teleparallel gravity by big bang nucleosynthesis. f(T) cosmology and BBN

    Energy Technology Data Exchange (ETDEWEB)

    Capozziello, S. [Universita di Napoli ' ' Federico II' ' , Complesso Universitario di Monte Sant' Angelo, Dipartimento di Fisica ' ' E. Pancini' ' , Napoli (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Napoli (Italy); Gran Sasso Science Institute, L' Aquila (Italy); Lambiase, G. [University of Salerno, Dipartimento di Fisica E.R. Cainaiello, Fisciano (Italy); INFN, Gruppo Collegato di Salerno, Sezione di Napoli, Fisciano (Italy); Saridakis, E.N. [National Technical University of Athens, Department of Physics, Athens (Greece); Baylor University, CASPER, Physics Department, Waco, TX (United States)

    2017-09-15

    We use Big Bang Nucleosynthesis (BBN) observational data on the primordial abundance of light elements to constrain f(T) gravity. The three most studied viable f(T) models, namely the power law, the exponential and the square-root exponential are considered, and the BBN bounds are adopted in order to extract constraints on their free parameters. For the power-law model, we find that the constraints are in agreement with those obtained using late-time cosmological data. For the exponential and the square-root exponential models, we show that for reliable regions of parameters space they always satisfy the BBN bounds. We conclude that viable f(T) models can successfully satisfy the BBN constraints. (orig.)

  3. Constraining f(T) teleparallel gravity by big bang nucleosynthesis: f(T) cosmology and BBN.

    Science.gov (United States)

    Capozziello, S; Lambiase, G; Saridakis, E N

    2017-01-01

    We use Big Bang Nucleosynthesis (BBN) observational data on the primordial abundance of light elements to constrain f ( T ) gravity. The three most studied viable f ( T ) models, namely the power law, the exponential and the square-root exponential are considered, and the BBN bounds are adopted in order to extract constraints on their free parameters. For the power-law model, we find that the constraints are in agreement with those obtained using late-time cosmological data. For the exponential and the square-root exponential models, we show that for reliable regions of parameters space they always satisfy the BBN bounds. We conclude that viable f ( T ) models can successfully satisfy the BBN constraints.

  4. 178th International School of Physics "Enrico Fermi" : From the Big Bang to the Nucleosynthesis

    CERN Document Server

    Nappi, E

    2011-01-01

    Physicists have devoted much effort to reproducing the conditions of the primordial universe in laboratory conditions in their quest to work out a comprehensive theory of the appearance and evolution of nuclear matter. Whether it be trying to recreate the predicted primordial state of high-energy density matter in which quarks and gluons are effectively deconfined - the so-called Quark Gluon Plasma (QGP) - or exploring the structure and reaction properties of very unstable nuclei in experiments using radioactive beams, they have striven to understand the events which characterized the Big Bang and the various nucleosynthesis mechanisms which occur in the stars. This book contains the proceedings of the 2010 Enrico Fermi summer school held in Varenna, Italy, in July 2010, and devoted to the present understanding of the primordial universe and the origin of the elements, as achieved by studying nuclei and their constituents in extreme regimes of energy and composition. Subjects covered include: QGP formation; e...

  5. Testing the Friedmann equation: The expansion of the universe during big-bang nucleosynthesis

    International Nuclear Information System (INIS)

    Carroll, Sean M.; Kaplinghat, Manoj

    2002-01-01

    In conventional general relativity, the expansion rate H of a Robertson-Walker universe is related to the energy density by the Friedmann equation. Aside from the present day, the only epoch at which we can constrain the expansion history in a model-independent way is during big-bang nucleosynthesis (BBN). We consider a simple two-parameter characterization of the behavior of H during BBN and derive constraints on this parameter space, finding that the allowed region of parameter space is essentially one dimensional. We also study the effects of a large neutrino asymmetry within this framework. Our results provide a simple way to compare an alternative cosmology to the observational requirement of matching the primordial abundances of the light elements

  6. Constraining f(T) teleparallel gravity by big bang nucleosynthesis. f(T) cosmology and BBN

    International Nuclear Information System (INIS)

    Capozziello, S.; Lambiase, G.; Saridakis, E.N.

    2017-01-01

    We use Big Bang Nucleosynthesis (BBN) observational data on the primordial abundance of light elements to constrain f(T) gravity. The three most studied viable f(T) models, namely the power law, the exponential and the square-root exponential are considered, and the BBN bounds are adopted in order to extract constraints on their free parameters. For the power-law model, we find that the constraints are in agreement with those obtained using late-time cosmological data. For the exponential and the square-root exponential models, we show that for reliable regions of parameters space they always satisfy the BBN bounds. We conclude that viable f(T) models can successfully satisfy the BBN constraints. (orig.)

  7. Constraining f( T) teleparallel gravity by big bang nucleosynthesis. f(T) cosmology and BBN

    Science.gov (United States)

    Capozziello, S.; Lambiase, G.; Saridakis, E. N.

    2017-09-01

    We use Big Bang Nucleosynthesis (BBN) observational data on the primordial abundance of light elements to constrain f( T) gravity. The three most studied viable f( T) models, namely the power law, the exponential and the square-root exponential are considered, and the BBN bounds are adopted in order to extract constraints on their free parameters. For the power-law model, we find that the constraints are in agreement with those obtained using late-time cosmological data. For the exponential and the square-root exponential models, we show that for reliable regions of parameters space they always satisfy the BBN bounds. We conclude that viable f( T) models can successfully satisfy the BBN constraints.

  8. Nuclear astrophysics: Recent results on CNO-cycle reactions and AGB nucleosynthesis

    International Nuclear Information System (INIS)

    La Cognata, M.

    2011-01-01

    Nuclear astrophysics aims to measure nuclear-reaction cross sections of astrophysical interest to be included into models to study stellar evolution and nucleosynthesis. Low energies, < 100 keV, are requested for this is the window where these processes are more effective. Two effects have prevented to achieve a satisfactory knowledge of the relevant nuclear processes, namely the Coulomb barrier exponentially suppressing the cross section and the presence of atomic electrons. These difficulties have triggered theoretical and experimental investigations to extend our knowledge down to astrophysical energies. For instance, indirect techniques such as the Trojan Horse Method and new experimental facilities such as deep underground laboratories have been devised yielding new cutting-edge results.

  9. Aspherical nucleosynthesis in a core-collapse supernova with 25 M {sub ☉} standard progenitor

    Energy Technology Data Exchange (ETDEWEB)

    Popov, M. V. [École Normale Supérieure de Lyon, CRAL (UMR CNRS 5574), Université de Lyon 1, 46 allée d' Italie, F-69007 Lyon (France); Filina, A. A.; Baranov, A. A.; Chardonnet, P. [LAPTh, Université de Savoie, 9, Chemin de Bellevue BP 110, F-74941 Annecy-le-Vieux Cedex (France); Chechetkin, V. M. [Keldysh Institute of Applied Mathematics RAS, Miusskaya sq. 4, 125047 Moscow (Russian Federation)

    2014-03-01

    The problem of nucleosynthesis was studied within an aspherical supernova model. The explosive burning was computed in a star of 25 M {sub ☉} initial mass on its final stage of evolution. The chemical composition of a presupernova was taken from realistic evolutionary computations. A piecewise parabolic method on a local stencil was applied to simulate the hydrodynamics of the explosion. The gravity was recomputed by a Poisson solver on a fine grid as the explosion developed. A detailed yield of chemical elements was performed as a post-processing step using the tracer particles method. The produced nuclei formed a layer-like structure enclosing large fragments of nickel and iron-group isotopes that were pushed away from the central region by an explosion along the polar direction. The light nuclei were preferentially moving along the equatorial plane forming a torus-like structure.

  10. Gas distribution regulations (Nova Scotia)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-11-03

    A consolidation of Nova Scotia`s gas distribution regulations made under subsection 42(1) of the Gas Distribution Act S.N.S. 1997, c4 - O.I.C. 1998-576 (November 10, 1998), N.S. Reg. 86/98 are presented. The consolidation is issued for reference purposes only, and while it has no official sanction, it is considered useful in providing an interpretation of the regulation, explaining franchise evaluation, the granting of franchises, and exemptions from application requirements. 1 tab.

  11. Chaotic amplification of neutrino chemical potentials by neutrino oscillations in big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Shi, X.

    1996-01-01

    We investigate in detail the parameter space of active-sterile neutrino oscillations that amplifies neutrino chemical potentials at the epoch of big bang nucleosynthesis. We calculate the magnitude of the amplification and show evidence of chaos in the amplification process. We also discuss the implications of the neutrino chemical potential amplification in big bang nucleosynthesis. It is shown that with a ∼1 eV ν e , the amplification of its chemical potential by active-sterile neutrino oscillations can lower the effective number of neutrino species at big bang nucleosynthesis to significantly below three. copyright 1996 The American Physical Society

  12. Chaotic amplification of neutrino chemical potentials by neutrino oscillations in big bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Shi, X. [Department of Physics, Queen`s University, Kingston, Ontario, K7L 3N6 (CANADA)

    1996-08-01

    We investigate in detail the parameter space of active-sterile neutrino oscillations that amplifies neutrino chemical potentials at the epoch of big bang nucleosynthesis. We calculate the magnitude of the amplification and show evidence of chaos in the amplification process. We also discuss the implications of the neutrino chemical potential amplification in big bang nucleosynthesis. It is shown that with a {approximately}1 eV {nu}{sub {ital e}}, the amplification of its chemical potential by active-sterile neutrino oscillations can lower the effective number of neutrino species at big bang nucleosynthesis to significantly below three. {copyright} {ital 1996 The American Physical Society.}

  13. Big bang nucleosynthesis with Gaussian inhomogeneous neutrino degeneracy

    International Nuclear Information System (INIS)

    Stirling, Spencer D.; Scherrer, Robert J.

    2002-01-01

    We consider the effect of inhomogeneous neutrino degeneracy on big bang nucleosynthesis for the case where the distribution of neutrino chemical potentials is given by a Gaussian. The chemical potential fluctuations are taken to be isocurvature, so that only inhomogeneities in the electron chemical potential are relevant. Then the final element abundances are a function only of the baryon-photon ratio η, the effective number of additional neutrinos ΔN ν , the mean electron neutrino degeneracy parameter ξ-bar, and the rms fluctuation of the degeneracy parameter, σ ξ . We find that for fixed η, ΔN ν , and ξ-bar, the abundances of 4 He, D, and 7 Li are, in general, increasing functions of σ ξ . Hence, the effect of adding a Gaussian distribution for the electron neutrino degeneracy parameter is to decrease the allowed range for η. We show that this result can be generalized to a wide variety of distributions for ξ

  14. Light element nucleosynthesis and estimates of the universal baryon density

    International Nuclear Information System (INIS)

    Mathews, G.J.; Viola, V.E.

    1978-01-01

    The present mean universal baryon density rho/sub b/, is of interest because it and the Hubble constant determine the curvature of the Universe. The available indicators of rho/sub b/ come from the present deuterium abundance, if it is assumed that ''big-bang'' nucleosynthesis must produce enough D to at least match the abundance of this nuclide in the interstellar medium. An alternative method utilizing the 7 Li/D ratio is used to evaluate rho/sub b/. With this method the difficulty associated with the astration process can be essentially canceled from the problem. The results obtained indicate an open Universe with a best guess for rho/sub b/ of 7.1 x 10 -31 g/cm 3 . 1 figure, 1 table

  15. Big Bang nucleosynthesis and the quark-hadron transition

    International Nuclear Information System (INIS)

    Kurki-suonio, H.; Matzner, R.A.; Olive, K.A.; Schramm, D.N.

    1989-12-01

    An examination and brief review is made of the effects of quark-hadron transistion induced fluctuations on Big Bang nucleosynthesis. It is shown that cosmologically critical densities in baryons are difficult to reconcile with observation, but the traditional baryon density constraints from homogeneous calculations might be loosened by as much as 50 percent, to 0.3 of critical density, and the limit on the number of neutrino flavors remains about N(sub nu) is less than or approximately 4. To achieve baryon densities of greater than or approximately 0.3 of critical density would require initial density contrasts R much greater than 10(exp 3), whereas the simplest models for the transition seem to restrict R to less than approximately 10(exp 2)

  16. Big Bang nucleosynthesis and abundances of light elements

    International Nuclear Information System (INIS)

    Pagel, B.E.J.

    1991-01-01

    Big Bang nucleosynthesis (BBNS) theory is sketched, indicating the dependence of primordial abundances of D, 3 He, 4 He and 7 Li on the mean baryonic density of the universe and the dependence of 4 He on the number of neutrino families and the neutron half-life. Observational data and inferred primordial abundances of these elements are reviewed and shown to be consistent (within errors) either with standard BBNS in a homogeneous universe about 100 seconds after the Big Bang or with moderately inhomogeneous BBNS models resulting from earlier phase transitions like the quark-hadron transition if this is first order. However, models with closure density supplied by baryons are apparently ruled out. Finally, implications for the existence of baryonic and non-baryonic dark matter are briefly discussed. (orig.)

  17. Big bang nucleosynthesis and the quark-hadron transition

    Science.gov (United States)

    Kurki-Suonio, Hannu; Matzner, Richard A.; Olive, Keith A.; Schramm, David N.

    1990-01-01

    An examination and brief review is made of the effects of quark-hadron transition induced fluctuations on Big Bang nucleosynthesis. It is shown that cosmologically critical densities in baryons are difficult to reconcile with observation, but the traditional baryon density constraints from homogeneous calculations might be loosened by as much as 50 percent, to 0.3 of critical density, and the limit on the number of neutrino flavors remains about N(sub nu) is less than or approximately 4. To achieve baryon densities of greater than or approximately 0.3 of critical density would require initial density contrasts R is much greater the 10(exp e), whereas the simplest models for the transition seem to restrict R to less than of approximately 10(exp 2).

  18. np→dγ for big-bang nucleosynthesis

    International Nuclear Information System (INIS)

    Chen, Jiunn-Wei; Savage, Martin J.

    1999-01-01

    The cross section for np→dγ is calculated at energies relevant to big-bang nucleosynthesis using the recently developed effective field theory that describes the two-nucleon sector. The E1 amplitude is computed up to N 3 LO and depends only upon nucleon-nucleon phase shift data. In contrast, the M1 contribution is computed up to next-to-leading order, and the four-nucleon-one-magnetic-photon counterterm that enters is determined by the cross section for cold neutron capture. The uncertainty in the calculation for nucleon energies up to E∼1 MeV is estimated to be (less-or-similar sign)4%. (c) 1999 The American Physical Society

  19. Implication of the Proton-Deuteron Radiative Capture for Big Bang Nucleosynthesis.

    Science.gov (United States)

    Marcucci, L E; Mangano, G; Kievsky, A; Viviani, M

    2016-03-11

    The astrophysical S factor for the radiative capture d(p,γ)^{3}He in the energy range of interest for big bang nucleosynthesis (BBN) is calculated using an ab initio approach. The nuclear Hamiltonian retains both two- and three-nucleon interactions-the Argonne v_{18} and the Urbana IX, respectively. Both one- and many-body contributions to the nuclear current operator are included. The former retain for the first time, besides the 1/m leading order contribution (m is the nucleon mass), also the next-to-leading order term, proportional to 1/m^{3}. The many-body currents are constructed in order to satisfy the current conservation relation with the adopted Hamiltonian model. The hyperspherical harmonics technique is applied to solve the A=3 bound and scattering states. Particular attention is paid in this second case in order to obtain, in the energy range of BBN, an uncertainty on the astrophysical S factor of the order or below ∼1%. Then, in this energy range, the S factor is found to be ∼10% larger than the currently adopted values. Part of this increase (1%-3%) is due to the 1/m^{3} one-body operator, while the remaining is due to the new more accurate scattering wave functions. We have studied the implication of this new determination for the d(p,γ)^{3}He S factor on the deuterium primordial abundance. We find that the predicted theoretical value for ^{2}H/H is in excellent agreement with its experimental determination, using the most recent determination of the baryon density of the Planck experiment, and with a standard number of relativistic degrees of freedom N_{eff}=3.046 during primordial nucleosynthesis. This calls for a more accurate measurement of the astrophysical S factor in order to confirm the present predictions.

  20. Single Degenerate Models for Type Ia Supernovae: Progenitor's Evolution and Nucleosynthesis Yields

    Science.gov (United States)

    Nomoto, Ken'ichi; Leung, Shing-Chi

    2018-06-01

    We review how the single degenerate models for Type Ia supernovae (SNe Ia) works. In the binary star system of a white dwarf (WD) and its non-degenerate companion star, the WD accretes either hydrogen-rich matter or helium and undergoes hydrogen and helium shell-burning. We summarize how the stability and non-linear behavior of such shell-burning depend on the accretion rate and the WD mass and how the WD blows strong wind. We identify the following evolutionary routes for the accreting WD to trigger a thermonuclear explosion. Typically, the accretion rate is quite high in the early stage and gradually decreases as a result of mass transfer. With decreasing rate, the WD evolves as follows: (1) At a rapid accretion phase, the WD increase its mass by stable H burning and blows a strong wind to keep its moderate radius. The wind is strong enough to strip a part of the companion star's envelope to control the accretion rate and forms circumstellar matter (CSM). If the WD explodes within CSM, it is observed as an "SN Ia-CSM". (X-rays emitted by the WD are absorbed by CSM.) (2) If the WD continues to accrete at a lower rate, the wind stops and an SN Ia is triggered under steady-stable H shell-burning, which is observed as a super-soft X-ray source: "SN Ia-SSXS". (3) If the accretion continues at a still lower rate, H shell-burning becomes unstable and many flashes recur. The WD undergoes recurrent nova (RN) whose mass ejection is smaller than the accreted matter. Then the WD evolves to an "SN Ia-RN". (4) If the companion is a He star (or a He WD), the accretion of He can trigger He and C double detonations at the sub-Chandrasekhar mass or the WD grows to the Chandrasekhar mass while producing a He-wind: "SN Ia-He CSM". (5) If the accreting WD rotates quite rapidly, the WD mass can exceed the Chandrasekhar mass of the spherical WD, which delays the trigger of an SN Ia. After angular momentum is lost from the WD, the (super-Chandra) WD contracts to become a delayed SN Ia

  1. Nova-driven winds in globular clusters

    International Nuclear Information System (INIS)

    Scott, E.H.; Durisen, R.H.

    1978-01-01

    Recent sensitive searches for Hα emission from ionized intracluster gas in globular clusters have set upper limits that conflict with theoretical predictions. We suggest that nova outbursts heat the gas, producing winds that resolve this discrepancy. The incidence of novae in globular clusters, the conversion of kinetic energy of the nova shell to thermal energy of the intracluster gas, and the characteristics of the resultant winds are discussed. Calculated emission from the nova-driven models does not conflict with any observations to date. Some suggestions are made concerning the most promising approaches for future detection of intracluster gas on the basis of these models. The possible relationship of nova-driven winds of globular cluster X-ray sources is also considered

  2. Nova laser assurance-management system

    International Nuclear Information System (INIS)

    Levy, A.J.

    1983-01-01

    In a well managed project, Quality Assurance is an integral part of the management activities performed on a daily basis. Management assures successful performance within budget and on schedule by using all the good business, scientific, engineering, quality assurance, and safety practices available. Quality assurance and safety practices employed on Nova are put in perspective by integrating them into the overall function of good project management. The Nova assurance management system was developed using the quality assurance (QA) approach first implemented at LLNL in early 1978. The LLNL QA program is described as an introduction to the Nova assurance management system. The Nova system is described pictorially through the Nova configuration, subsystems and major components, interjecting the QA techniques which are being pragmatically used to assure the successful completion of the project

  3. Computational Astrophysics Consortium 3 - Supernovae, Gamma-Ray Bursts and Nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Woosley, Stan [Univ. of California, Santa Cruz, CA (United States)

    2014-08-29

    Final project report for UCSC's participation in the Computational Astrophysics Consortium - Supernovae, Gamma-Ray Bursts and Nucleosynthesis. As an appendix, the report of the entire Consortium is also appended.

  4. Some effects of high temperature and density on neutron-capture nucleosynthesis

    International Nuclear Information System (INIS)

    Norman, E.B.; Kellogg, S.E.

    1984-01-01

    Examples of nuclear reactions between nuclei in excited states, beta decays of nuclear excited states, and bound-state beta decays are shown. The effects of these processes on selected problems in heavy-element nucleosynthesis are discussed. 40 references

  5. Nova Scotia's new gas distribution regime

    Energy Technology Data Exchange (ETDEWEB)

    MacIsaac, J.B. [Cox Hanson O' Reilly Matheson, Halifax, NS (Canada)

    2002-07-01

    The most recent amendments to Nova Scotia's gas distribution regime were described in detail. The amended legislation includes: (1) elimination of mandatory service targets, (2) franchise terms of 25 years, (3) a 10 year prohibition on industrial by-pass, (4) gas sales licenses are now required to market gas in Nova Scotia, (5) distributors can offer bundled services, (6) the elimination of province wide uniform tolls for low volume customers, (7) public utilities are permitted to apply for a distribution franchise and to market natural gas, (8) ex-party filing of interim rates, (9) the Pipeline Act applies to the construction of gas distribution systems, (10) socio-economic studies are required for parties seeking a single-end user franchise outside a franchise area, and (11) regulations for underground gas storage have been removed from the legislation. It was noted that these significant changes to the statutory framework of Nova Scotia's delivery of natural gas are sending encouraging signals to parties considering investing in the distribution network in the province. It was also noted, that as in any industry, success of natural gas distribution in Nova Scotia will depend on economics and not on structural changes. 66 refs.

  6. Big-bang nucleosynthesis through bound-state effects with a long-lived slepton in the NMSSM

    Science.gov (United States)

    Kohri, Kazunori; Koike, Masafumi; Konishi, Yasufumi; Ohta, Shingo; Sato, Joe; Shimomura, Takashi; Sugai, Kenichi; Yamanaka, Masato

    2014-08-01

    We show that the Li problems can be solved in the next-to-minimal supersymmetric standard model where the slepton as the next-to-lightest supersymmetric (SUSY) particle is very long lived. Such a long-lived slepton induces exotic nuclear reactions in big-bang nucleosynthesis, and destroys and produces the Li7 and Li6 nuclei via bound state formation. We study cases where the lightest SUSY particle is singlino-like neutralino and bino-like neutralino to present allowed regions in the parameter space, which is consistent with the observations on the dark matter and the Higgs mass.

  7. Primordial nucleosynthesis in inhomogeneous cosmologies: Ω = 1 with baryonic dark matter

    International Nuclear Information System (INIS)

    Mathews, G.J.; Sale, K.E.

    1986-09-01

    We consider the constraints on Ω from primordial nucleosynthesis in inhomogeneous cosmologies. We find that allowance for isothermal fluctuations significantly weakens the upper bound on the average value of Ω derived from the standard big bang. Under the plausible additional assumption that regions of high baryon density are preferentially absorbed into cold dark matter, the constraints from primordial nucleosynthesis can be satisfied for large values of Ω, including Ω = 1. 22 refs., 2 figs

  8. Nuclear structure near the particle drip-lines and explosive nucleosynthesis processes

    International Nuclear Information System (INIS)

    Kratz, K.L.; Pfeiffer, B.; Moeller, P.; Thielemann, F.K.; Wiescher, M.

    1999-01-01

    In this paper, we discuss the nuclear physics input for a selected set of explosive nucleosynthesis scenarios leading to rapid proton-- and neutron--capture processes. Observables (like e.g. luminosity curves or elemental abundance distributions) witness the interplay between nuclear structure aspects near the particle drip-lines and the appropriate astrophysical environments, and can give guidance to and constraints on stellar conditions and the associated nucleosynthesis. (authors)

  9. TIDAL NOVAE IN COMPACT BINARY WHITE DWARFS

    International Nuclear Information System (INIS)

    Fuller, Jim; Lai Dong

    2012-01-01

    Compact binary white dwarfs (WDs) undergoing orbital decay due to gravitational radiation can experience significant tidal heating prior to merger. In these WDs, the dominant tidal effect involves the excitation of outgoing gravity waves in the inner stellar envelope and the dissipation of these waves in the outer envelope. As the binary orbit decays, the WDs are synchronized from outside in (with the envelope synchronized first, followed by the core). We examine the deposition of tidal heat in the envelope of a carbon-oxygen WD and study how such tidal heating affects the structure and evolution of the WD. We show that significant tidal heating can occur in the star's degenerate hydrogen layer. This layer heats up faster than it cools, triggering runaway nuclear fusion. Such 'tidal novae' may occur in all WD binaries containing a CO WD, at orbital periods between 5 minutes and 20 minutes, and precede the final merger by 10 5 -10 6 years.

  10. Nova Gas`s pipeline to Asia

    Energy Technology Data Exchange (ETDEWEB)

    Lea, N.

    1996-01-01

    The involvement of the Calgary-based company NOVA Gas International (NGI) in Malaysia`s peninsular gas utilization (PGU) project, was described. Phase I and II of the project involved linking onshore gas processing plants with a natural gas transmission system. Phase III of the PGU project was a gas transmission pipeline that began midway up the west coast of peninsular Malaysia to the Malaysia-Thailand border. The complex 549 km pipeline included route selection, survey and soil investigation, archaeological study, environmental impact assessment, land acquisition, meter-station construction, telecommunication systems and office buildings. NGI was the prime contractor on the project through a joint venture with OGP Technical Services, jointly owned by NGI and Petronas, the Thai state oil company. Much of NGI`s success was attributed to excellent interpersonal skills, particularly NGI`s ability to build confidence and credibility with its Thai partners.

  11. Nova laser alignment control system

    International Nuclear Information System (INIS)

    Van Arsdall, P.J.; Holloway, F.W.; McGuigan, D.L.; Shelton, R.T.

    1984-01-01

    Alignment of the Nova laser requires control of hundreds of optical components in the ten beam paths. Extensive application of computer technology makes daily alignment practical. The control system is designed in a manner which provides both centralized and local manual operator controls integrated with automatic closed loop alignment. Menudriven operator consoles using high resolution color graphics displays overlaid with transport touch panels allow laser personnel to interact efficiently with the computer system. Automatic alignment is accomplished by using image analysis techniques to determine beam references points from video images acquired along the laser chain. A major goal of the design is to contribute substantially to rapid experimental turnaround and consistent alignment results. This paper describes the computer-based control structure and the software methods developed for aligning this large laser system

  12. Orbital periods of recurrent novae

    International Nuclear Information System (INIS)

    Schaefer, B.E.

    1990-01-01

    The class of recurrent novae (RN) with thermonuclear runaways contains only three systems (T Pyx, U Sco, and V394 CrA), for which no orbital periods are known. This paper presents a series of photometric observations where the orbital periods for all three systems are discovered. T Pyx is found to have sinusoidal modulation with an amplitude of 0.08 mag and a period of 2.3783 h (with a possible alias of 2.6403 h). U Sco is found to be an eclipsing system with an eclipse amplitude of roughly 1.5 mag and an orbital period of 1.2344 days. V394 CrA is found to have sinusoidal modulation with an amplitude of 0.5 mag and a period of 0.7577 days. Thus two out of three RN with thermonuclear runaways (or five out of six for all RN) have evolved companions. 16 refs

  13. Ten-year literature review of global endometrial ablation with the NovaSure® device

    Directory of Open Access Journals (Sweden)

    Gimpelson RJ

    2014-03-01

    Full Text Available Richard J Gimpelson Mercy Clinic, Minimally Invasive Gynecology, Department of Obstetrics and Gynecology, Mercy Hospital St Louis, St Louis, MO, USA Abstract: This review examines the peer-reviewed literature describing prospective studies that report amenorrhea rates, patient satisfaction, and surgical reintervention rates following the NovaSure® endometrial ablation procedure. A search of the English-language literature published from 2000 to 2011 was conducted using PubMed. Ten prospective studies, six single-arm NovaSure trials, and four randomized controlled trials comparing the NovaSure procedure with other global endometrial ablation modalities met the inclusion criteria and were reviewed. The follow-up periods ranged from 6 to 60 months. Amenorrhea rates for the NovaSure procedure ranged from 30.0% to 75.0%. Patients who reported being satisfied with the NovaSure procedure ranged from 85.0% to 94.0%. In randomized controlled trials with other global endometrial ablation modalities, amenorrhea rates at 12 months with the NovaSure procedure ranged from 43.0% to 56.0%, while other modalities ranged from 8% to 24%. In addition, this manuscript reviews the following: the NovaSure technology; use of the NovaSure procedure in the office setting; intraoperative and postoperative pain; effects on premenstrual syndrome (PMS; dysmenorrhea; special circumstances, including presence of uterine disease, history of cesarean delivery, coagulopathy, or use of anticoagulant medication; post-procedure uterine cavity assessment and cancer risk; contraception and pregnancy; and safety. Keywords: abnormal uterine bleeding, menorrhagia, endometrial ablation, NovaSure®

  14. Time-Dependent Dust Formation in Novae

    Directory of Open Access Journals (Sweden)

    Kyung-Won Suh

    1991-06-01

    Full Text Available The dust formation processes in novae are investigated with close attention to recent infrared observations. Using mainly the classical nucleation theory, we have calculated the time scales of dust formation and growth in the environments of novae. Those time scales roughly resemble the typical observations. We have classified the dust-forming novae into three classes according to their explosion properties and the thermodynamic properties of dust grains. Oxygen grains from much later than carbon grains because of their thermodynamic properties. The effect of grain formation to the efficiency of stellar winds to drive the material outward is tested with newly obtained Planck mean values of dust grains.

  15. The Revival of Galactic Cosmic-Ray Nucleosynthesis?

    International Nuclear Information System (INIS)

    Fields, B.D.; Olive, K.A.

    1999-01-01

    Because of the roughly linear correlation between Be/H and Fe/H in low-metallicity halo stars, it has been argued that a open-quotes primaryclose quotes component in the nucleosynthesis of Be must be present in addition to the open-quotes secondaryclose quotes component from standard Galactic cosmic-ray nucleosynthesis. In this paper we critically reevaluate the evidence for the primary versus secondary character of Li, Be, and B (LiBeB) evolution, analyzing both the observations and Galactic chemical evolution models. Although it appears that [Be/H] versus [Fe/H] has a logarithmic slope near 1, it is rather the Be-O trend that directly arises from the physics of spallation production. Using new abundances for oxygen in halo stars based on UV OH lines, we find that in Population II stars for which O has been measured, the Be-O slope has a large uncertainty due to systematic effects. Namely, the Be-O logarithmic slope lies in the range 1.3 endash 1.8, rendering it difficult to distinguish from the data between the secondary slope of 2 and the primary slope of 1. The possible difference between the Be-Fe and Be-O slopes is a consequence of the variation in O/Fe versus Fe: recent data suggest that the best-fit O/Fe-Fe slope for Population II is in the range -0.5 to -0.2, rather than zero (i.e., Fe∝O) as is often assumed. In addition to this phenomenological analysis of Be and B evolution, we have also examined the predicted LiBeB, O, and Fe trends in Galactic chemical evolution models that include outflow. Based on our results, it is possible that a good fit to the LiBeB evolution requires only the traditional Galactic cosmic-ray spallation and the (primary) neutrino-process contribution to 11 B. We thus suggest that these two processes might be sufficient to explain 6 Li, Be, and B evolution in the Galaxy, without the need for an additional primary source of Be and B. However, the uncertainties in the data at this time prevent one from reaching a definitive

  16. Nova outburst modeling and its application to the recurrent nova phenomenon

    International Nuclear Information System (INIS)

    Sparks, W.M.; Starrfield, S.; Truran, J.

    1985-12-01

    The thermonuclear runaway (TNR) theory for the cause of the common novae is reviewed. Numerical simulations of this theory were performed using an implicit hydrodynamic Lagrangian computer code. Relevant physical phenomena are explained with the simpler envelope-in-place calculations. Next the models that include accretion are discussed. The calculations agree very well with observations of common novae. The observational differences between common novae and recurrent novae are examined. We propose input parameters to the TNR model which can give the outburst characteristics of RS Ophiuchi and discuss the implications. This review is concluded with a brief discussion of two current topics in novae research: shear mixing on the white dwarf and Neon novae. 36 refs., 4 figs

  17. A Qualitative Study of Doctors of Chiropractic in a Nova Scotian Practice-based Research Network: Barriers and Facilitators to the Screening and Management of Psychosocial Factors for Patients With Low Back Pain.

    Science.gov (United States)

    Stilwell, Peter; Hayden, Jill A; Des Rosiers, Piaf; Harman, Katherine; French, Simon D; Curran, Janet A; Hefford, Warren

    2018-01-01

    This study aimed to assess chiropractors' awareness of clinical practice guidelines for low back pain and to identify barriers and facilitators to the screening and management of psychosocial factors in patients with low back pain. This qualitative study used semi-structured interviews informed by the Theoretical Domains Framework with 10 Nova Scotian chiropractors who were members of a practice-based research network. The participants correctly identified what the guidelines generally recommend and described the value of psychosocial factors; however, none of the participants could name specific clinical practice guidelines for low back pain. We identified 6 themes related to barriers and facilitators for chiropractors screening and managing psychosocial factors. The themes revolved around the participants' desire to fulfill patients' anatomy-focused treatment expectations and a perceived lack of training for managing psychosocial factors. Participants had concerns about going beyond the chiropractic scope of practice, and they perceived a lack of practical psychosocial screening and management resources. Social factors, such as the influence of other health care practitioners, were reported as both barriers and facilitators to screening and managing psychosocial factors. The participants in this study reported that they mostly treated with an anatomical and biomechanical focus and that they did not always address psychosocial factors identified in their patients with low back pain. Although these findings are limited to Nova Scotian chiropractors, the barriers identified appeared to be potentially modifiable and could be considered in other groups. Low-cost interventions, such as continuing education using evidence-informed behavior change techniques, could be considered to address these barriers. Copyright © 2017. Published by Elsevier Inc.

  18. Mass spectrometry of stardust : experimental tests of nucleosynthesis

    International Nuclear Information System (INIS)

    Clayton, R.N.

    1997-01-01

    Primitive meteorites contain grains of diamond, graphite and silicon carbide which condensed from the outflows of red-giant stars, which existed before the formation of our Sun and Solar System. Nuclear processes within the parent star have modified the isotopic compositions of all elements in the grains. By means of a very sensitive and selective microanalytical technique, Resonant Ionization Mass Spectrometry, we can measure isotopic abundances of trace metals in individual 3-micrometer-sized crystals. The technique uses multi-photon photoionization with tuned lasers to ionize a single element selectively and efficiently. This allows isotopic measurements of trace constituents in complex systems. Results from zirconium and molybdenum in presolar silicon carbide grains show large enhancements in the s-process isotopes, and depletion by factors >2 in the r-process and p-process isotopes. The observations are in good agreement with recent calculations of s-process nucleosynthesis in Asymptotic Giant Branch stars. These results confirm the classical subdivision of nucleo-synthetic processes into p-, r-, and s-processes and show that the principal site of the s-process is in carbon-rich red giant stars. (author)

  19. Constraining pre big-bang-nucleosynthesis expansion using cosmic antiprotons

    International Nuclear Information System (INIS)

    Schelke, M.; Catena, R.; Fornengo, N.; Masiero, A.; Pietroni, M.

    2006-06-01

    A host of dark energy models and non-standard cosmologies predict an enhanced Hubble rate in the early Universe: perfectly viable models, which satisfy Big Bang Nucleosynthesis (BBN), cosmic microwave background and general relativity tests, may nevertheless lead to enhancements of the Hubble rate up to many orders of magnitude. In this paper we show that strong bounds on the pre-BBN evolution of the Universe may be derived, under the assumption that dark matter is a thermal relic, by combining the dark matter relic density bound with constraints coming from the production of cosmic-ray antiprotons by dark matter annihilation in the Galaxy. The limits we derive can be sizable and apply to the Hubble rate around the temperature of dark matter decoupling. For dark matter masses lighter than 100 GeV, the bound on the Hubble-rate enhancement ranges from a factor of a few to a factor of 30, depending on the actual cosmological model, while for a mass of 500 GeV the bound falls in the range 50-500. Uncertainties in the derivation of the bounds and situations where the bounds become looser are discussed. We finally discuss how these limits apply to some specific realizations of non-standard cosmologies: a scalar-tensor gravity model, kination models and a Randall-Sundrum D-brane model. (Orig.)

  20. Chaos and turbulent nucleosynthesis prior to a supernova explosion

    Directory of Open Access Journals (Sweden)

    W. D. Arnett

    2014-03-01

    Full Text Available Three-dimensional (3D, time dependent numerical simulations of flow of matter in stars, now have sufficient resolution to be fully turbulent. The late stages of the evolution of massive stars, leading up to core collapse to a neutron star (or black hole, and often to supernova explosion and nucleosynthesis, are strongly convective because of vigorous neutrino cooling and nuclear heating. Unlike models based on current stellar evolutionary practice, these simulations show a chaotic dynamics characteristic of highly turbulent flow. Theoretical analysis of this flow, both in the Reynolds-averaged Navier-Stokes (RANS framework and by simple dynamic models, show an encouraging consistency with the numerical results. It may now be possible to develop physically realistic and robust procedures for convection and mixing which (unlike 3D numerical simulation may be applied throughout the long life times of stars. In addition, a new picture of the presupernova stages is emerging which is more dynamic and interesting (i.e., predictive of new and newly observed phenomena than our previous one.

  1. Constraining pre big-bang-nucleosynthesis expansion using cosmic antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Schelke, M. [Istituto Nazionale di Fisica Nucleare, Torino (Italy); Catena, R. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Fornengo, N. [Torino Univ. (Italy). Dipt. di Fisica Teorica]|[Istituto Nazionale di Fisica Nucleare, Torino (Italy); Masiero, A. [Pavoa Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Padova (Italy); Pietroni, M. [Istituto Nazionale di Fisica Nucleare, Padova (Italy)

    2006-06-15

    A host of dark energy models and non-standard cosmologies predict an enhanced Hubble rate in the early Universe: perfectly viable models, which satisfy Big Bang Nucleosynthesis (BBN), cosmic microwave background and general relativity tests, may nevertheless lead to enhancements of the Hubble rate up to many orders of magnitude. In this paper we show that strong bounds on the pre-BBN evolution of the Universe may be derived, under the assumption that dark matter is a thermal relic, by combining the dark matter relic density bound with constraints coming from the production of cosmic-ray antiprotons by dark matter annihilation in the Galaxy. The limits we derive can be sizable and apply to the Hubble rate around the temperature of dark matter decoupling. For dark matter masses lighter than 100 GeV, the bound on the Hubble-rate enhancement ranges from a factor of a few to a factor of 30, depending on the actual cosmological model, while for a mass of 500 GeV the bound falls in the range 50-500. Uncertainties in the derivation of the bounds and situations where the bounds become looser are discussed. We finally discuss how these limits apply to some specific realizations of non-standard cosmologies: a scalar-tensor gravity model, kination models and a Randall-Sundrum D-brane model. (Orig.)

  2. r-process nucleosynthesis in dynamic helium-burning environments

    Science.gov (United States)

    Cowan, J. J.; Cameron, A. G. W.; Truran, J. W.

    1985-01-01

    The results of an extended examination of r-process nucleosynthesis in helium-burning enviroments are presented. Using newly calculated nuclear rates, dynamical r-process calculations have been made of thermal runaways in helium cores typical of low-mass stars and in the helium zones of stars undergoing supernova explosions. These calculations show that, for a sufficient flux of neutrons produced by the C-13 neutron source, r-process nuclei in solar proportions can be produced. The conditions required for r-process production are found to be 10 to the 20th-10 to the 21st neutrons per cubic centimeter for times of 0.01-0.1 s and neutron number densities in excess of 10 to the 19th per cubic centimeter for times of about 1 s. The amount of C-13 required is found to be exceedingly high - larger than is found to occur in any current stellar evolutionary model. It is thus unlikely that these helium-burning environments are responsible for producing the bulk of the r-process elements seen in the solar system.

  3. Primordial Black Holes and r-Process Nucleosynthesis.

    Science.gov (United States)

    Fuller, George M; Kusenko, Alexander; Takhistov, Volodymyr

    2017-08-11

    We show that some or all of the inventory of r-process nucleosynthesis can be produced in interactions of primordial black holes (PBHs) with neutron stars (NSs) if PBHs with masses 10^{-14}  M_{⊙}

  4. The r-process nucleosynthesis: Nuclear physics challenges

    Energy Technology Data Exchange (ETDEWEB)

    Goriely, S. [Institut d' Astronomie et d' Astrophysique, Universite Libre de Bruxelles Campus de la Plaine, CP 226, 1050 Brussels (Belgium)

    2012-10-20

    About half of the nuclei heavier than iron observed in nature are produced by the socalled rapid neutron capture process, or r-process, of nucleosynthesis. The identification of the astrophysics site and the specific conditions in which the r-process takes place remains, however, one of the still-unsolved mysteries of modern astrophysics. Another underlying difficulty associated with our understanding of the r-process concerns the uncertainties in the predictions of nuclear properties for the few thousands exotic neutron-rich nuclei involved and for which essentially no experimental data exist. The present contribution emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the nuclear structure properties of exotic neutron-rich nuclei as well as their radiative neutron capture rates and their fission probabilities. These quantities are particularly relevant to determine the composition of the matter resulting from the r-process. Their impact on the r-abundance distribution resulting from the decompression of neutron star matter is discussed.

  5. Observational constraints on secret neutrino interactions from big bang nucleosynthesis

    Science.gov (United States)

    Huang, Guo-yuan; Ohlsson, Tommy; Zhou, Shun

    2018-04-01

    We investigate possible interactions between neutrinos and massive scalar bosons via gϕν ¯ν ϕ (or massive vector bosons via gVν ¯γμν Vμ) and explore the allowed parameter space of the coupling constant gϕ (or gV) and the scalar (or vector) boson mass mϕ (or mV) by requiring that these secret neutrino interactions (SNIs) should not spoil the success of big bang nucleosynthesis (BBN). Incorporating the SNIs into the evolution of the early Universe in the BBN era, we numerically solve the Boltzmann equations and compare the predictions for the abundances of light elements with observations. It turns out that the constraint on gϕ and mϕ in the scalar-boson case is rather weak, due to a small number of degrees of freedom (d.o.f.). However, in the vector-boson case, the most stringent bound on the coupling gV≲6 ×10-10 at 95% confidence level is obtained for mV≃1 MeV , while the bound becomes much weaker gV≲8 ×10-6 for smaller masses mV≲10-4 MeV . Moreover, we discuss in some detail how the SNIs affect the cosmological evolution and the abundances of the lightest elements.

  6. Big bang nucleosynthesis: The standard model and alternatives

    Science.gov (United States)

    Schramm, David N.

    1991-01-01

    Big bang nucleosynthesis provides (with the microwave background radiation) one of the two quantitative experimental tests of the big bang cosmological model. This paper reviews the standard homogeneous-isotropic calculation and shows how it fits the light element abundances ranging from He-4 at 24% by mass through H-2 and He-3 at parts in 10(exp 5) down to Li-7 at parts in 10(exp 10). Furthermore, the recent large electron positron (LEP) (and the stanford linear collider (SLC)) results on the number of neutrinos are discussed as a positive laboratory test of the standard scenario. Discussion is presented on the improved observational data as well as the improved neutron lifetime data. Alternate scenarios of decaying matter or of quark-hadron induced inhomogeneities are discussed. It is shown that when these scenarios are made to fit the observed abundances accurately, the resulting conlusions on the baryonic density relative to the critical density, omega(sub b) remain approximately the same as in the standard homogeneous case, thus, adding to the robustness of the conclusion that omega(sub b) approximately equals 0.06. This latter point is the driving force behind the need for non-baryonic dark matter (assuming omega(sub total) = 1) and the need for dark baryonic matter, since omega(sub visible) is less than omega(sub b).

  7. Big bang nucleosynthesis: The standard model and alternatives

    International Nuclear Information System (INIS)

    Schramm, D.N.

    1991-01-01

    Big bang nucleosynthesis provides (with the microwave background radiation) one of the two quantitative experimental tests of the big bang cosmological model. This paper reviews the standard homogeneous-isotropic calculation and shows how it fits the light element abundances ranging from 4 He at 24% by mass through 2 H and 3 He at parts in 10 5 down to 7 Li at parts in 10 10 . Furthermore, the recent LEP (and SLC) results on the number of neutrinos are discussed as a positive laboratory test of the standard scenario. Discussion is presented on the improved observational data as well as the improved neutron lifetime data. Alternate scenarios of decaying matter or of quark-hadron induced inhomogeneities are discussed. It is shown that when these scenarios are made to fit the observed abundances accurately, the resulting conclusions on the baryonic density relative to the critical density, Ω b , remain approximately the same as in the standard homogeneous case, thus, adding to the robustness of the conclusion that Ω b ≅0.06. This latter point is the driving force behind the need for non-baryonic dark matter (assuming Ω total =1) and the need for dark baryonic matter, since Ω visible b . (orig.)

  8. The exact parity symmetric model and big bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Foot, R.; Volkas, R.R.

    1996-12-01

    The assumption of exact, unbroken parity symmetry leads directly to a simple predictive resolution of the atmospheric and solar neutrino puzzles. This is because the existence of this symmetry implies the existence of a set of mirror neutrinos which must mix maximally with the known neutrinos if neutrinos have mass. the maximal mixing of the electron neutrino with the mirror electron neutrino with 3 x 10{sup -10} eV{sup 2} {<=} |{delta}m{sup 2}| {<=} 10{sup -3} eV{sup 2} leads to a predicted reduction of the solar neutrino flux by-a factor of 2, which is in quite good agreement with the experiments. The maximal mixing of the muon neutrino with the mirror muon neutrino with |{delta}m{sup 2}| {approx} 10{sup -2} eV{sup 2} also solves the atmospheric neutrino puzzle. We show that there is a significant range of parameters where these solutions are not in conflict with standard Big Bang Nucleosynthesis when the creation of lepton asymmetry due to neutrino oscillations is taken into account. (authors).

  9. r-process nucleosynthesis in dynamic helium-burning environments

    International Nuclear Information System (INIS)

    Cowan, J.J.; Cameron, A.G.W.; Truran, J.W.

    1985-01-01

    The results of an extended examination of r-process nucleosynthesis in helium-burning environments are presented. Using newly calculated nuclear rates, dynamical r-process calculations have been made of thermal runaways in helium cores typical of low-mass stars and in the helium zones of stars undergoing supernova explosions. These calculations show that, for a sufficient flux of neutrons produced by the 13 C neutron source, r-process nuclei in solar proportions can be produced. The conditions required for r-process production are found to be: 10 20 --10 21 neutrons cm -3 for times of 0.01--0.1 s and neutron number densities in excess of 10 19 cm -3 for times of approx.1 s. The amount of 13 C required is found to be exceedingly high: larger than is found to occur in any current stellar evolutionary model. It is thus unlikely that these helium-burning environments are responsible for producing the bulk of the r-process elements seen in the solar system

  10. Explosive nucleosynthesis in a neutrino-driven core collapse supernova

    International Nuclear Information System (INIS)

    Fujimoto, Shin-ichiro; Kotake, Kei; Hashimoto, Masa-aki; Ono, Masaomi; Ohnishi, Naofumi

    2010-01-01

    We investigate explosive nucleosynthesis in a delayed neutrino-driven, supernova explosion aided by standing accretion shock instability (SASI), based on two-dimensional hydrodynamic simulations of the explosion of a 15 M · star. We take into accounts neutrino heating and cooling as well as change in electron fraction due to weak interactions appropriately, in the two-dimensional simulations. We assume the isotropic emission of neutrinos from the neutrino spheres with given luminosities. and the Fermi-Dirac distribution of given temperatures. We find that the stalled shock revives due to the neutrino heating aided by SASI for cases with L νe ≥3.9x10 52 ergss -1 and the as-pherical shock passes through the outer layers of the star (≥10,000 km), with the explosion energies of ∼10 51 ergs.Next we examine abundances and masses of the supernova ejecta. We find that masses of the ejecta and 56 Ni correlate with the neutrino luminosity, and 56 Ni mass is comparable to that observed in SN 1987A. We also find that abundance pattern of the supernova ejecta is similar to that of the solar system, for cases with high explosion energies of >10 51 ergs. We emphasize that 64 Zn, which is underproduced in the spherical case, is abundantly produced in slightly neutron-rich ejecta.

  11. Copernicus observations of Nova Cygni 1975

    Science.gov (United States)

    Jenkins, E. B.; Snow, T. P.; Upson, W. L.; Anderson, R.; Starrfield, S. G.; Gallagher, J. S.; Friedjung, M.; Linsky, J. L.; Henry, R. C.; Moos, H. W.

    1977-01-01

    Near-ultraviolet radiation from Nova Cygni 1975 was detected by the Copernicus satellite on five occasions from 1975 September 1 to 1975 September 9. The nova was not seen in the UV after this date. The principal result was the observation of a broad emission feature from the Mg II doublet at 2800 A. The absence of strong UV radiation at shorter wavelengths suggests that these lines are produced by collisional excitation in the outer layers of an expanding shell with electron temperature of approximately 4000 K. The absence of observed emission lines from highly ionized species indicates that the amount of material with log T between 4.4 and 5.7 is less than 0.001 times that which produces the Mg II emission. The continuum flux in the near-UV decreased as the nova evolved, showing that the total luminosity decreased as the nova faded in the visible.

  12. Proceedings of the 2003 Annual Meeting of the Canadian Mathematics Education Study Group = Actes de la Rencontre Annuelle 2003 du Groupe Canadien d'Etude en Didactique des Mathematiques (27th, Wolfville, Nova Scotia, Canada, May 30-June 3, 2003)

    Science.gov (United States)

    Simmt, Elaine, Ed.; Davis, Brent, Ed.

    2004-01-01

    This submission contains the Proceedings of the 2003 Annual Meeting of the Canadian Mathematics Education Study Group (CMESG), held at Acadia University in Wolfville, Nova Scotia. The CMESG is a group of mathematicians and mathematics educators who meet annually to discuss mathematics education issues at all levels of learning. The aims of the…

  13. Continuum emission from classical nova winds

    International Nuclear Information System (INIS)

    Harkness, R.P.

    1983-01-01

    The emergent continuum of a slow classical nova during outburst is considered in the quasi-steady optically thick, transonic wind model. Models are presented for various steady mass loss rates and are related to the evolution of slow novae during decline and early post-maximum. The continuum emission is found to depart radically from a blackbody spectrum and to exhibit features common to highly extended stellar atmospheres. (author)

  14. Rate of nova production in the Galaxy

    International Nuclear Information System (INIS)

    Liller, W.; Mayer, B.; PROBLICOM Sky Survey, Los Angeles, CA)

    1987-01-01

    The ongoing PROBLICOM program in the Southern Hemisphere now makes it possible to derive a reliable value for the overall production rate of Galactic novae. The results, 73 + or - 24/y, indicates that the Galaxy outproduces M 31 by a factor of two or three. It is estimated that the rate of supernova ejecta is one and a half orders of magnitude greater than that of novae in the Galaxy. 15 references

  15. NOVA Corporation of Alberta annual report, 1992

    International Nuclear Information System (INIS)

    1993-01-01

    Nova Corporation and its related businesses are involved in natural gas production, gas pipelines, consulting services, and upgrading of natural gas into chemicals and plastics. Nova owns Alberta Gas Transmission Division, the primary gas transportation system in Alberta, with 11,400 miles of pipeline and total deliveries in 1992 of 3.4 trillion ft 3 . Nova also owns 50% of Foothills Pipe Lines Ltd., one of Canada's largest carriers of exported gas, and 50% of TQM Pipeline Partnership, which transports natural gas in Quebec. Nova conducts its chemicals business through Novacor Chemicals Ltd., which has plants in Alberta, Ontario, Quebec, and the USA. Novacor's major petrochemicals are methanol, ethylene, propylene, and styrene and its major plastics are polystyrene, polypropylene, and polyethylene. Nova's gas-producing branch Novalta Resources produced 26 billion ft 3 of natural gas in 1992 and has proven reserves of 334 billion ft 3 . Nova's net income in 1992 was $164 million, compared to only $46 million in 1991. The company's operations, along with management discussion and analysis, are presented for 1992 and financial statements are included. 20 figs., 43 tabs

  16. Optimization of a high-yield, low-areal-density fusion product source at the National Ignition Facility with applications in nucleosynthesis experiments

    Science.gov (United States)

    Gatu Johnson, M.; Casey, D. T.; Hohenberger, M.; Zylstra, A. B.; Bacher, A.; Brune, C. R.; Bionta, R. M.; Craxton, R. S.; Ellison, C. L.; Farrell, M.; Frenje, J. A.; Garbett, W.; Garcia, E. M.; Grim, G. P.; Hartouni, E.; Hatarik, R.; Herrmann, H. W.; Hohensee, M.; Holunga, D. M.; Hoppe, M.; Jackson, M.; Kabadi, N.; Khan, S. F.; Kilkenny, J. D.; Kohut, T. R.; Lahmann, B.; Le, H. P.; Li, C. K.; Masse, L.; McKenty, P. W.; McNabb, D. P.; Nikroo, A.; Parham, T. G.; Parker, C. E.; Petrasso, R. D.; Pino, J.; Remington, B.; Rice, N. G.; Rinderknecht, H. G.; Rosenberg, M. J.; Sanchez, J.; Sayre, D. B.; Schoff, M. E.; Shuldberg, C. M.; Séguin, F. H.; Sio, H.; Walters, Z. B.; Whitley, H. D.

    2018-05-01

    Polar-direct-drive exploding pushers are used as a high-yield, low-areal-density fusion product source at the National Ignition Facility with applications including diagnostic calibration, nuclear security, backlighting, electron-ion equilibration, and nucleosynthesis-relevant experiments. In this paper, two different paths to improving the performance of this platform are explored: (i) optimizing the laser drive, and (ii) optimizing the target. While the present study is specifically geared towards nucleosynthesis experiments, the results are generally applicable. Example data from T2/3He-gas-filled implosions with trace deuterium are used to show that yield and ion temperature (Tion) from 1.6 mm-outer-diameter thin-glass-shell capsule implosions are improved at a set laser energy by switching from a ramped to a square laser pulse shape, and that increased laser energy further improves yield and Tion, although by factors lower than predicted by 1 D simulations. Using data from D2/3He-gas-filled implosions, yield at a set Tion is experimentally verified to increase with capsule size. Uniform D3He-proton spectra from 3 mm-outer-diameter CH shell implosions demonstrate the utility of this platform for studying charged-particle-producing reactions relevant to stellar nucleosynthesis.

  17. Exposição múltipla a agrotóxicos e efeitos à saúde: estudo transversal em amostra de 102 trabalhadores rurais, Nova Friburgo, RJ Multiple exposure to pesticides and impacts on health: a cross-section study of 102 rural workers, Nova Friburgo, Rio de Janeiro State, Brazil

    Directory of Open Access Journals (Sweden)

    Alberto José de Araújo

    2007-03-01

    Full Text Available Um estudo transversal foi realizado em uma comunidade agrícola localizada em Nova Friburgo, RJ, para conhecer os aspectos epidemiológicos, clínicos e laboratoriais da exposição múltipla a agrotóxicos em uma amostra representativa de 102 pequenos agricultores, de ambos os sexos. Os trabalhadores foram submetidos a um extenso protocolo que incluía aplicação de questionário ocupacional, coleta de amostras biológicas para exame toxicológico e avaliação clínica - geral e neurológica. Os resultados dos exames toxicológicos revelaram episódios leves a moderados de intoxicação aguda aos organofosforados descritos pelos agricultores ou observados durante o exame clínico. Foram também diagnosticados 13 (12,8 % quadros de neuropatia tardia e 29 (28,5% quadros de síndrome neurocomportamental e distúrbios neuropsiquiátricos associados ao uso crônico de agrotóxicos. Os resultados apontam para a ocorrência de episódios recorrentes de sobre-exposição múltipla, a elevadas concentrações de diversos produtos químicos, com grave prejuízo para as funções vitais desses trabalhadores, especialmente por se encontrarem em uma faixa etária jovem (média = 35 ± 11anos e período produtivo da vida. Estes dados demonstram a importância do monitoramento da múltipla exposição a agrotóxicos, uma cadeia de eventos de grande repercussão na saúde pública e para o meio ambiente.A cross section study was carried out in a farming community from Nova Friburgo, Rio de Janeiro state, Brazil, to examine epidemiological, clinical and laboratory aspects of multiple exposure to pesticides in a representative sample of 102 small farmers. Both males and females were submitted to an extensive protocol which included an occupation questionnaire, biological sample collection for toxicology analysis and clinical - general and neurological - evaluation. The toxicology test results showed light to moderate episodes of acute intoxication by

  18. Atmospheric deposition 2000. NOVA 2003; Atmosfaerisk deposition 2000. NOVA 2003

    Energy Technology Data Exchange (ETDEWEB)

    Ellermann, T.; Hertel, O.; Hovmand, M.F.; Kemp, K.; Skjoeth, C.A.

    2001-11-01

    This report presents measurements and calculations from the atmospheric part of NOVA 2003 and covers results for 2000. It summarises the main results concerning concentrations and depositions of nitrogen, phosphorus and sulphur compounds related to eutrophication and acidification. Depositions of atmospheric compounds to Danish marine waters as well as land surface are presented. Measurements: In 2000 the monitoring program consisted of eight stations where wet deposition of ammonium, nitrate, phosphate (semi quantitatively) and sulphate were measured using bulk precipitation samplers. Six of the stations had in addition measurements of atmospheric content of A, nitrogen, phosphorus, and sulphur compounds in gas and particulate phase carried out by use of filter pack samplers. Filters were analysed at the National Environmental Research Institute. Furthermore nitrogen dioxide were measured using nitrogen dioxide filter samplers and monitors. Model calculations: The measurements in the monitoring program were supplemented with model calculations of concentrations and depositions of nitrogen and sulphur compounds to Danish land surface, marine waters, fjords and bays using the ACDEP model (Atmospheric Chemistry and Deposition). The model is a so-called trajectory model and simulates the physical and chemical processes in the atmosphere using meteorological and emission data as input. The advantage of combining measurements with model calculations is that the strengths of both methods is obtained. Conclusions concerning: 1) actual concentration levels at the monitoring stations, 2) deposition at the monitoring stations, 3) seasonal variations and 4) long term trends in concentrations and depositions are mainly based on the direct measurements. These are furthermore used to validate the results of the model calculations. Calculations and conclusions concerning: 1) depositions to land surface and to the individual marine water, 2) contributions from different emission

  19. Novas tecnologias, novas competências New Tecnologies, new skills

    Directory of Open Access Journals (Sweden)

    Geneviève Jacquinot Delaunay

    2008-01-01

    Full Text Available O texto aborda a relação dos jovens e adolescentes com tecnologias, nem "novas" nem "velhas", e sim instrumentos para informar e comunicar, divertir, auxiliar nos trabalhos escolares. Apesar de reconhecer a familiaridade dessa geração com o que há de mais avançado em termos de tecnologia, aponta a necessidade de se compreender a complexidade desse novo cenário de aprendizagem, que envolve o aprofundamento de conceitos como interatividade e interação, linguagem numérica, multimídia, internet e hipertexto. Na seqüência, faz uma análise do contato dos jovens com essa diversidade de meios, suas implicações no processo cognitivo e suas conseqüências comunicacionais. Finalmente, reconhece que a aprendizagem é hipercomplexa e que - apesar de todo avanço científico - a máquina, mesmo interativa, não pode proporcionar ao indivíduo o aprendizado que lhe proporciona a interação com outras pessoas.The paper discusses how young people relate to technology, not seen as new or old, but as an instrument to communicate and keep informed, amuse and to help in school projects. Although it is clear that the new generations are much more familiarized with new technology, the focus is on the need to understand the complexity of the new scenario, which requires a deeper understanding of the concepts of interactivity, multimedia, internet and hypertext. It is discussed how young people enter in contact with this diversity of instruments. It is stressed, however, that no matter how complex the computer can be, nothing can replace the role of interacting with other people in the learning process.

  20. A proposal to study the esophageal transit by biomagnetic and scintigraphic study; Uma nova proposta para o estudo do transito esofagiano atraves das tecnicas biomagneticas e cintilograficas

    Energy Technology Data Exchange (ETDEWEB)

    Daghastanli, N.A.; Braga, F.J.H.N.; Baffa, O. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica; Oliveira, R.B. [Faculdade de Medicina de Ribeirao Preto, SP (Brazil)

    1996-12-31

    The initial results for a new apparatus to study the esophageal transit time is studied in asymptomatic persons for a yogurt bolus (10 ml). The bolus is uniformly labeled with 5 g of ferrite powder (biomagnetic study, B) or 350 MBq of {sup 99m} Tc (scintigraphic study, C). For the B study the detection is made by means two pair of coils in opposite phase excited by a 10 k Hz sinusoidal voltage. The signal response is obtained when the bolus traverses the coils placed on the regions-of-interest (ROIs) of the esophagus (furcula, F and xiphoid process, X) and produces a signal voltage that is measured by a lock-in amplifier Stanford SR530. For C studies an Orbiter Siemens scintillation camera is used linked to a computer. The data analysis shows a (4.1{+-}0.7)s in B studies and (3.7{+-}0.9)s in C studies (R=0.6, P<0.07) 8 refs., 3 figs.

  1. Report on terrestrial biology research and logistics at Baia Terra Nova Station

    Directory of Open Access Journals (Sweden)

    Satoshi Imura

    1999-11-01

    Full Text Available From December 4,1998 to January 15,1999,the author stayed at Baia Terra Nova Station (Italy in Antarctica, as an exchange scientist. To compare the biodiversity between Syowa Station and the Baia Terra Nova Station area, many samples of mosses, lichens, algae and micro animals in the soil were collected, and the structure of moss vegetation was studied in various fields around the station. Some characteristic features of logistics at the station were also researched.

  2. Climate change in Nova Scotia : a background paper to guide Nova Scotia's climate change action plan

    International Nuclear Information System (INIS)

    2007-10-01

    Climate change causes changes in the temperature of the earth, the level of the sea, and the frequency of extreme weather conditions. The province of Nova Scotia recently released an act related to environmental goals and sustainable prosperity. Addressing climate change is a key element in achieving Nova Scotia's sustainable prosperity goals outlined in the act. The Nova Scotia Department of Energy is working towards developing both policy and action, to help meet its target of a 10 per cent reduction in greenhouse gases from 1990 levels by the year 2020. Two major plans are underway, notably a climate change action plan and a renewed energy strategy. This report provided background information on Nova Scotia's climate change action plan. It discussed climate change issues affecting Nova Scotia, air pollutants, energy sources in Nova Scotia, energy consumers in the province, and Nova Scotia's approach to climate change. The report also discussed actions underway and funding sources. It was concluded that in order for the climate change action plan to be successful, Nova Scotians must use energy more efficiently; use renewable energy; use cleaner energy; and plan for change. 13 refs., 2 tabs., 6 figs., 4 appendices

  3. The r-process nucleosynthesis and related challenges

    Directory of Open Access Journals (Sweden)

    Goriely Stephane

    2017-01-01

    Full Text Available The rapid neutron-capture process, or r-process, is known to be of fundamental importance for explaining the origin of approximately half of the A > 60 stable nuclei observed in nature. Recently, special attention has been paid to neutron star (NS mergers following the confirmation by hydrodynamic simulations that a non-negligible amount of matter can be ejected and by nucleosynthesis calculations combined with the predicted astrophysical event rate that such a site can account for the majority of r-material in our Galaxy. We show here that the combined contribution of both the dynamical (prompt ejecta expelled during binary NS or NS-black hole (BH mergers and the neutrino and viscously driven outflows generated during the post-merger remnant evolution of relic BH-torus systems can lead to the production of r-process elements from mass number A ≳ 90 up to actinides. The corresponding abundance distribution is found to reproduce the solar distribution extremely well. It can also account for the elemental distributions observed in low-metallicity stars. However, major uncertainties still affect our understanding of the composition of the ejected matter. These concern (i the β-interactions of electron (antineutrinos with free neutrons and protons, as well as their inverse reactions, which may affect the neutron-richness of the matter at the early phase of the ejection, and (ii the nuclear physics of exotic neutron-rich nuclei, including nuclear structure as well as nuclear interaction properties, which impact the calculated abundance distribution. Both aspects are discussed in the light of recent hydrodynamical simulations of NS mergers and microscopic calculations of nuclear decay and reaction probabilities.

  4. Constraints on vacuum energy from structure formation and Nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Fred C.; Grohs, Evan [Physics Department, University of Michigan, 450 Church Street, Ann Arbor, MI, 48109 (United States); Alexander, Stephon [Physics Department, Brown University, 6127 Wilder Laboratory, Providence, RI, 02912 (United States); Mersini-Houghton, Laura, E-mail: fca@umich.edu, E-mail: stephon_alexander@brown.edu, E-mail: egrohs@umich.edu, E-mail: mersini@physics.unc.edu [Physics Department, University of North Carolina, 120 E. Cameron Avenue, Chapel Hill, NC, 27599 (United States)

    2017-03-01

    This paper derives an upper limit on the density ρ{sub Λ} of dark energy based on the requirement that cosmological structure forms before being frozen out by the eventual acceleration of the universe. By allowing for variations in both the cosmological parameters and the strength of gravity, the resulting constraint is a generalization of previous limits. The specific parameters under consideration include the amplitude Q of the primordial density fluctuations, the Planck mass M {sub pl}, the baryon-to-photon ratio η, and the density ratio Ω {sub M} /Ω {sub b} . In addition to structure formation, we use considerations from stellar structure and Big Bang Nucleosynthesis (BBN) to constrain these quantities. The resulting upper limit on the dimensionless density of dark energy becomes ρ{sub Λ}/ M {sub pl}{sup 4} < 10{sup −90}, which is ∼30 orders of magnitude larger than the value in our universe ρ{sub Λ}/ M {sub pl}4 ∼ 10{sup −120}. This new limit is much less restrictive than previous constraints because additional parameters are allowed to vary. With these generalizations, a much wider range of universes can develop cosmic structure and support observers. To constrain the constituent parameters, new BBN calculations are carried out in the regime where η and G = M {sub pl}{sup −2} are much larger than in our universe. If the BBN epoch were to process all of the protons into heavier elements, no hydrogen would be left behind to make water, and the universe would not be viable. However, our results show that some hydrogen is always left over, even under conditions of extremely large η and G , so that a wide range of alternate universes are potentially habitable.

  5. NuSTAR Observations of Fermi-detected Novae, V339 Delphini and V5668 Sagitarii

    Science.gov (United States)

    Mukai, K.; Nelson, T.; Sokoloski, J.; Chomiuk, L.; Finzell, T.; Linford, J.; Weston, J.; Rupen, M.; Mioduszewski, A.

    2017-10-01

    Ten Galactic novae have been detected as transient GeV gamma-ray sources with Fermi/LAT to date, presumably due to shock acceleration that produces relativistic particles. This unexpected discovery highlights the complexity of the mass ejection process in novae. It has also added a new class of objects in which particle acceleration can be studied. We can in principle study the same shock in X-rays through their thermal emission and the lower energy extension of the non-thermal emission. Here we present our NuSTAR observations of two Fermi-detected novae, V339 Del and V5668 Sgr, that were carried out while they were being detected with the LAT. We did not detect thermal or non-thermal emissions from these novae. Our results place a tight limit on the properties of the putative shocks in V339 Del and V5668 Sgr. We also compare our results with previous reports of possible detection of non-thermal hard X-rays from novae, and discuss the implications in the context of our current understanding of the complicated process of mass ejection in novae.

  6. THE RADIO LIGHT CURVE OF THE GAMMA-RAY NOVA IN V407 CYG: THERMAL EMISSION FROM THE IONIZED SYMBIOTIC ENVELOPE, DEVOURED FROM WITHIN BY THE NOVA BLAST

    Energy Technology Data Exchange (ETDEWEB)

    Chomiuk, Laura; Krauss, Miriam I.; Rupen, Michael P.; Roy, Nirupam; Mioduszewski, Amy [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Nelson, Thomas [School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); Sokoloski, Jennifer L.; Weston, Jennifer [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Mukai, Koji [CRESST and X-ray Astrophysics Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States); Munari, Ulisse [INAF Astronomical Observatory of Padova, I-36012 Asiago (VI) (Italy); O' Brien, Tim J. [Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL (United Kingdom); Eyres, Stewart P. S. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Bode, Michael F., E-mail: chomiuk@pa.msu.edu [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom)

    2012-12-20

    We present multi-frequency radio observations of the 2010 nova event in the symbiotic binary V407 Cygni, obtained with the Karl G. Jansky Very Large Array (VLA) and spanning 1-45 GHz and 17-770 days following discovery. This nova-the first ever detected in gamma rays-shows a radio light curve dominated by the wind of the Mira giant companion, rather than the nova ejecta themselves. The radio luminosity grew as the wind became increasingly ionized by the nova outburst, and faded as the wind was violently heated from within by the nova shock. This study marks the first time that this physical mechanism has been shown to dominate the radio light curve of an astrophysical transient. We do not observe a thermal signature from the nova ejecta or synchrotron emission from the shock, due to the fact that these components were hidden behind the absorbing screen of the Mira wind. We estimate a mass-loss rate for the Mira wind of M-dot{sub w} approx. 10{sup -6} M{sub Sun} yr{sup -1}. We also present the only radio detection of V407 Cyg before the 2010 nova, gleaned from unpublished 1993 archival VLA data, which shows that the radio luminosity of the Mira wind varies by a factor of {approx}>20 even in quiescence. Although V407 Cyg likely hosts a massive accreting white dwarf, making it a candidate progenitor system for a Type Ia supernova, the dense and radially continuous circumbinary material surrounding V407 Cyg is inconsistent with observational constraints on the environments of most Type Ia supernovae.

  7. The Radio Light Curve of the Gamma-Ray Nova in V407 CYG: Thermal Emission from the Ionized Symbiotic Envelope, Devoured from Within by the Nova Blast

    Science.gov (United States)

    Chomiuk, Laura; Krauss, Miriam I.; Rupen, Michael P.; Nelson, Thomas; Roy, Nirupam; Sokoloski, Jennifer L.; Mukai, Koji; Munari, Ulisse; Mioduszewski, Amy; Weston, Jeninfer; hide

    2012-01-01

    We present multi-frequency radio observations of the 2010 nova event in the symbiotic binary V407 Cygni, obtained with the Karl G. Jansky Very Large Array (VLA) and spanning 1.45 GHz and 17.770 days following discovery. This nova.the first ever detected in gamma rays.shows a radio light curve dominated by the wind of the Mira giant companion, rather than the nova ejecta themselves. The radio luminosity grewas the wind became increasingly ionized by the nova outburst, and faded as the wind was violently heated from within by the nova shock. This study marks the first time that this physical mechanism has been shown to dominate the radio light curve of an astrophysical transient. We do not observe a thermal signature from the nova ejecta or synchrotron emission from the shock, due to the fact that these components were hidden behind the absorbing screen of the Mira wind. We estimate a mass-loss rate for the Mira wind of .Mw approximately equals 10(exp -6) Solar mass yr(exp -1). We also present the only radio detection of V407 Cyg before the 2010 nova, gleaned from unpublished 1993 archival VLA data, which shows that the radio luminosity of the Mira wind varies by a factor of 20 even in quiescence. Although V407 Cyg likely hosts a massive accreting white dwarf, making it a candidate progenitor system for a Type Ia supernova, the dense and radially continuous circumbinary material surrounding V407 Cyg is inconsistent with observational constraints on the environments of most Type Ia supernovae.

  8. Impact of neutrino flavor oscillations on the neutrino-driven wind nucleosynthesis of an electron-capture supernova

    NARCIS (Netherlands)

    Pllumbi, E.; Tamborra, I.; Wanajo, S.; Janka, H.-T.; Hüdepohl, L.

    2015-01-01

    Neutrino oscillations, especially to light sterile states, can affect nucleosynthesis yields because of their possible feedback effect on the electron fraction (Ye). For the first time, we perform nucleosynthesis calculations for neutrino-driven wind trajectories from the neutrino-cooling phase of

  9. Multi-wavelength observations of novae in outburst

    International Nuclear Information System (INIS)

    Starrfield, S.; Arizona State Univ., Tempe, AZ

    1989-01-01

    This review serves as the introduction to the observational studies of novae and I will mention a number of results that will be emphasized by other reviewers. Therefore, I will try to provide the physical framework for multi-wavelength observations as applied to studies of novae. I divide the outburst into phases based on the physical effects that are occurring at that time. The first phase is the rise to bolometric maximum and occurs on a convective time scale. The second phase is the rise to visual maximum and occurs on the time scale for the envelope to expand to ∼10 12 cm. The third phase is the time when the nova is emitting at constant bolometric luminosity, but declining optical magnitude, and it lasts until most of the accreted material has been either exhausted or eroded from the surface of the white dwarf. The fourth and final phase is the return is the return to quiescence (turn-off phase) and it occurs at the time that nuclear burning is ending. I will discuss each of these phases in turn and end with a discussion. 36 refs

  10. Dust formation and ionization in novae

    International Nuclear Information System (INIS)

    Yamamoto, Tetsuo; Sato, Shuji; Nariai, Kyoji.

    1979-01-01

    In order to explain the fact that some novae show the increase of infrared radiation indicating the formation of circumstellar dust grains while some others do not, the theory that the formation of dust in the circumstellar envelope of a nova depends on the intensity of ultraviolet radiation from a central star has been presented. It is known that the central star of a nova emits radiation at nearly constant rate, and its effective temperature rises. It was concluded that the novae with higher emission than a certain value are the poor candidates for dust formation because the whole envelope is ionized before dust is formed. But this conclusion is misleading. The evolution of the ultraviolet radiation emanating from a central star is summarized. The condensation of grains is possible when the partial pressure of the vapor, from which the grains are formed, becomes higher than the saturation vapor pressure. The temperature of grains can be estimated by equating the radiations absorbed and emitted. The grains evaporate if the grain temperature is higher than the condensation temperature. The formation of a Stroemgren sphere in the exploding envelope of a nova is discussed. For the formation of grains, it is necessary that temperature drops below the condensation temperature before the whole envelope is ionized. Hence dust grains do not grow if the grain temperature at a phase is higher than the condensation temperature. (Kako, I.)

  11. General neutralino NLSP with gravitino dark matter vs. big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Hasenkamp, Jasper

    2009-08-01

    We study the scenario of gravitino dark matter with a general neutralino being the next-to-lightest supersymmetric particle (NLSP). Therefore, we compute analytically all 2- and 3-body decays of the neutralino NLSP to determine the lifetime and the electromagnetic and hadronic branching ratio of the neutralino decaying into the gravitino and Standard Model particles. We constrain the gravitino and neutralino NLSP mass via big bang nucleosynthesis and see how those bounds are relaxed for a Higgsino or a wino NLSP in comparison to the bino neutralino case. At neutralino masses >or similar 1 TeV, a wino NLSP is favoured, since it decays rapidly via a newly found 4-vertex. The Higgsino component becomes important, when resonant annihilation via heavy Higgses can occur. We provide the full analytic results for the decay widths and the complete set of Feynman rules necessary for these computations. This thesis closes any gap in the study of gravitino dark matter scenarios with neutralino NLSP coming from approximations in the calculation of the neutralino decay rates and its hadronic branching ratio. (orig.)

  12. General neutralino NLSP with gravitino dark matter vs. big bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Hasenkamp, Jasper

    2009-08-15

    We study the scenario of gravitino dark matter with a general neutralino being the next-to-lightest supersymmetric particle (NLSP). Therefore, we compute analytically all 2- and 3-body decays of the neutralino NLSP to determine the lifetime and the electromagnetic and hadronic branching ratio of the neutralino decaying into the gravitino and Standard Model particles. We constrain the gravitino and neutralino NLSP mass via big bang nucleosynthesis and see how those bounds are relaxed for a Higgsino or a wino NLSP in comparison to the bino neutralino case. At neutralino masses >or similar 1 TeV, a wino NLSP is favoured, since it decays rapidly via a newly found 4-vertex. The Higgsino component becomes important, when resonant annihilation via heavy Higgses can occur. We provide the full analytic results for the decay widths and the complete set of Feynman rules necessary for these computations. This thesis closes any gap in the study of gravitino dark matter scenarios with neutralino NLSP coming from approximations in the calculation of the neutralino decay rates and its hadronic branching ratio. (orig.)

  13. Bounds on long-lived charged massive particles from Big Bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Jedamzik, Karsten, E-mail: jedamzik@lpta.univ-montp2.fr [Laboratoire de Physique Mathémathique et Théorique, CNRS, Université de Montpellier II, F-34095 Montpellier Cedex 5 (France)

    2008-03-01

    The Big Bang nucleosynthesis (BBN) process in the presence of charged massive particles (CHAMPs) is studied in detail. All currently known effects due to the existence of bound states between CHAMPs and nuclei, including possible late-time destruction of {sup 6}Li and {sup 7}Li, are included. The study sets conservative bounds on CHAMP abundances in the decay time range 3×10{sup 2} s∼<τ{sub x}∼<10{sup 12} s. It is stressed that the production of {sup 6}Li at early times T∼10 keV is overestimated by a factor ∼10 when the approximation of the Saha equation for the {sup 4}He bound state fraction is utilized. To obtain conservative limits on the abundance of CHAMPs, a Monte Carlo analysis with ∼3 × 10{sup 6} independent BBN runs, varying the reaction rates of 19 different reactions, is performed. The analysis yields the surprising result that, except for small areas in the particle parameter space, conservative constraints on the abundance of decaying charged particles are currently very close to those of neutral particles. It is shown that, in the case that the rates of a number of heretofore unconsidered reactions may be determined reliably in the future, it is conceivable that the limit on CHAMPs in the early Universe could be tightened by orders of magnitude.

  14. Bounds on long-lived charged massive particles from Big Bang nucleosynthesis

    Science.gov (United States)

    Jedamzik, Karsten

    2008-03-01

    The Big Bang nucleosynthesis (BBN) process in the presence of charged massive particles (CHAMPs) is studied in detail. All currently known effects due to the existence of bound states between CHAMPs and nuclei, including possible late-time destruction of 6Li and 7Li, are included. The study sets conservative bounds on CHAMP abundances in the decay time range 3\\times 10^2~\\mathrm {s}\\lesssim \\tau_x\\lesssim 10^{12}~\\mathrm {s} . It is stressed that the production of 6Li at early times T~10 keV is overestimated by a factor ~10 when the approximation of the Saha equation for the 4He bound state fraction is utilized. To obtain conservative limits on the abundance of CHAMPs, a Monte Carlo analysis with ~3 × 106 independent BBN runs, varying the reaction rates of 19 different reactions, is performed. The analysis yields the surprising result that, except for small areas in the particle parameter space, conservative constraints on the abundance of decaying charged particles are currently very close to those of neutral particles. It is shown that, in the case that the rates of a number of heretofore unconsidered reactions may be determined reliably in the future, it is conceivable that the limit on CHAMPs in the early Universe could be tightened by orders of magnitude.

  15. Big bang nucleosynthesis with a varying fine structure constant and nonstandard expansion rate

    International Nuclear Information System (INIS)

    Ichikawa, Kazuhide; Kawasaki, Masahiro

    2004-01-01

    We calculate the primordial abundances of light elements produced during big bang nucleosynthesis when the fine structure constant and/or the cosmic expansion rate take nonstandard values. We compare them with the recent values of observed D, 4 He, and 7 Li abundances, which show a slight inconsistency among themselves in the standard big bang nucleosynthesis scenario. This inconsistency is not solved by considering either a varying fine structure constant or a nonstandard expansion rate separately but solutions are found by their simultaneous existence

  16. Constraining neutrino physics with big bang nucleosynthesis and cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Hansen, S.H.; Melchiorri, A.; Mangano, G.; Miele, G.; Pisanti, O.

    2002-01-01

    We perform a likelihood analysis of the recent results on the anisotropy of cosmic microwave background radiation from the BOOMERanG and DASI experiments to show that they single out an effective number of neutrinos in good agreement with standard big bang nucleosynthesis. We also consider degenerate big bang nucleosynthesis to provide new bounds on effective relativistic degrees of freedom N ν and, in particular, on the neutrino chemical potential ξ α . When including supernova type Ia data we find, at 2σ, N ν ≤7 and -0.01≤ξ e ≤0.22, vertical bar ξ μ,τ vertical bar ≤2.6

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

    Science.gov (United States)

    Kurki-Suonio, H; Sihvola, E

    2000-04-24

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

  18. Recent Astrophysical Studies with Exotic Beams at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Bardayan, Daniel W [ORNL

    2006-02-01

    The availability of exotic beams has produced great opportunities for advances in our understanding of the nucleosynthesis occurring in stellar burning and stellar explosions such as novae, X-ray bursts, and supernovae. In these extreme environments, synthesized radioactive nuclei can undergo subsequent nuclear processing before they decay, and thus to understand these events, we must understand reaction rates involving radioactive nuclei. At the ORNL Holi led Radioactive Ion Beam Facility (HRIBF), we have made several recent measurements using proton-rich beams such as 18F and 7Be and neutron-rich beams such as 82Ge and 84Se that help clarify the structure of astrophysically-important nuclei. We are also poised to begin studies with doubly-magic 132Sn. The experimental methods and results are discussed.

  19. Recent Astrophysical Studies with Exotic Beams at ORNL

    International Nuclear Information System (INIS)

    Bardayan, Daniel W.

    2006-01-01

    The availability of exotic beams has produced great opportunities for advances in our understanding of the nucleosynthesis occurring in stellar burning and stellar explosions such as novae, X-ray bursts, and supernovae. In these extreme environments, synthesized radioactive nuclei can undergo subsequent nuclear processing before they decay, and thus to understand these events, we must understand reaction rates involving radioactive nuclei. At the ORNL Holi led Radioactive Ion Beam Facility (HRIBF), we have made several recent measurements using proton-rich beams such as 18F and 7Be and neutron-rich beams such as 82Ge and 84Se that help clarify the structure of astrophysically-important nuclei. We are also poised to begin studies with doubly-magic 132Sn. The experimental methods and results are discussed.

  20. p-process nucleosynthesis via proton-capture reactions in thermonuclear supernovae explosions

    Directory of Open Access Journals (Sweden)

    Endres Anne

    2015-01-01

    Full Text Available Model calculations within the framework of the so-called γ process show an underproduction of the p nucleus with the highest isotopic abundace 92Mo. This discrepancy can be narrowed by taking into account the alternative production site of a type Ia supernova explosion. Here, the nucleus 92Mo can be produced by a sequence of proton-capture reactions. The amount of 92Mo nuclei produced via this reaction chain is most sensitive to the reactions 90Zr(p,γ and 91Nb(p,γ. Both rates have to be investigated experimentally to study the impact of this nucleosynthesis aspect on the long-standing 92Mo-problem. We have already measured the proton-capture reaction on 90Zr using high-resolution in-beam γ-ray spectroscopy. In this contribution, we will present our preliminary results of the total cross sections as well as the partial cross sections. Furthermore, we plan to measure the 91Nb(p,γ reaction soon. Due to the radioactive target material, the 91Nb nuclei have to be produced prior to the experiment. The current status of this production will be presented in this contribution.

  1. Radiative neutron capture on a proton at big-bang nucleosynthesis energies

    International Nuclear Information System (INIS)

    Ando, S.; Cyburt, R. H.; Hong, S. W.; Hyun, C. H.

    2006-01-01

    The total cross section for radiative neutron capture on a proton, np→dγ, is evaluated at big-bang nucleosynthesis (BBN) energies. The electromagnetic transition amplitudes are calculated up to next-to-leading-order within the framework of pionless effective field theory with dibaryon fields. We also calculate the dγ→np cross section and the photon analyzing power for the dγ(vector sign)→np process from the amplitudes. The values of low-energy constants that appear in the amplitudes are estimated by a Markov Chain Monte Carlo analysis using the relevant low-energy experimental data. Our result agrees well with those of other theoretical calculations except for the np→dγ cross section at some energies estimated by an R-matrix analysis. We also study the uncertainties in our estimation of the np→dγ cross section at relevant BBN energies and find that the estimated cross section is reliable to within ∼1% error

  2. Enquête de satisfaction Novae

    CERN Multimedia

    2014-01-01

    Novae lance une enquête de satisfaction auprès de ses clients. Vous pouvez accéder au questionnaire au sujet des trois restaurants d’entreprise du CERN en utilisant le lien et les codes ci-dessous. Le délai de réponse est fixé au jeudi 29 mai.   https://survey.mis-trend.ch/NOVAE Voici les codes à introduire (en respectant la casse) pour entrer dans le questionnaire, selon le site : CERN Restaurant n°1 : CERN114 CERN Restaurant n°2 : CERN214 CERN Restaurant n°3 : CERN314   Nous attirons votre attention sur le fait que tout questionnaire rempli sera validé. Nous vous prions donc de ne pas utiliser ce lien pour tester le questionnaire. Merci d’avance pour votre collaboration. L'équipe Novae

  3. Novae, supernovae, and the island universe hypothesis

    International Nuclear Information System (INIS)

    Van Den Bergh, S.

    1988-01-01

    Arguments in Curtis's (1917) paper related to the island universe hypothesis and the existence of novae in spiral nebulae are considered. It is noted that the maximum magnitude versus rate-of-decline relation for novae may be the best tool presently available for the calibration of the extragalactic distance scale. Light curve observations of six novae are used to determine a distance of 18.6 + or - 3.5 MPc to the Virgo cluster. Results suggest that Type Ia supernovae cannot easily be used as standard candles, and that Type II supernovae are unsuitable as distance indicators. Factors other than precursor mass are probably responsible for determining the ultimate fate of evolving stars. 83 references

  4. Nova: the laser fusion breakeven experiment

    International Nuclear Information System (INIS)

    Godwin, R.O.; Glaze, J.A.; Hagen, W.F.; Holzrichter, J.F.; Simmons, W.W.; Trenholme, J.B.

    1979-01-01

    A new laboratory building is being constructed adjacent to the Shiva laser to house the Phase I $137M ten-beam Nova laser and a target chamber designed for twenty beams. The first ten beams will be operational in early 1980. Following Phase I, it is planned that the Shiva laser will be shut down and upgraded into ten Nova laser beams. These beams will then be combined with Nova Phase I beams to provide the full twenty beams having a minimum output energy of 300 kJ in a 3 nc pulse, or a power capability of 300 terawatts (10 12 watts) in a 100 ps pulse. This paper will describe the Phase I engineering project

  5. Nova variedade de Menta arvensis

    Directory of Open Access Journals (Sweden)

    Abelardo Rodrigues Lima

    1952-09-01

    Full Text Available No quarto ano dos trabalhos de seleção com a menta japonêsa, foi encontrado um "seedling", o M. A. 701, que se destacou pela resistência à ferrugem e pela sua rusticidade. Os caracteres botânicos dessa variedade comercial, principalmente hábito vegetativo, coloração das fôlhas e das hastes, a tornam completa' mente distinta da variedade original. Esta distinção se confirma e acentua quando se compara a natureza dos componentes do óleo essencial da menta "Campinas" M. A. 701, descrita no presente trabalho, com a menta japonêsa comum. A maior produtividade da nova variedade comparada com a da menta japonesa comum foi desde logo também constatada pelos primeiros lavradores, a quem foram enviadas pequenas quantidades de rizomas, para plantio experimental. Foram cultivados em 1949-50 cêrca de 12 hectares; cm 1950-51, cêrca de 900 ha, e o prognóstico é que essa variedade tende a substituir totalmente a menta japonêsa anteriormente cultivada em São Paulo, devido ao seu maior valor econômico.A seedling, designated M.A.701, remarkable for its vigor and resistance to rust, was discovered during the fourth year of selection of Japanese mint (Mentha arvensis L. subsp. haplocalix Briquet var. piperascens Holmes or forma piperascens Malinvaud. The botanical characters of the variety derived from this seedling, especially the vegetative habit and colouring of leaves and stems, make it quite different from the original variety. This difference is enhanced, when we compare the nature of the essential oil components of "Campinas" M.A.701, as described in the present paper, with that of the common Japanese mint. The higher yield of the new variety, compared with that of the common Japanese mint, was soon confirmed by the first cultivators, to whom small quantities of rhizomes were sent for experimental planting. About 12 hectars were cultivated em 1949/50 and about 900 hectars in 1950/51. It is expected that the new variety will, on account

  6. Spectral evolution of Nova V400 Per (1974) and Nova V373 Sct (1975)

    International Nuclear Information System (INIS)

    Rosino, L.

    1978-01-01

    Photographic and spectroscopic observations of the two galactic novae, V400 Per and V373 Sct, which appeared in 1974 and 1975, have been carried out at Asiago. The light curves of the two novae were characterized by the presence of brightness oscillations during the early decline. The spectral evolution was quite normal: the spectra showed at first, over a relatively strong continuum, wide emission bands of moderate excitation, accompanied by blueshifted absorptions, with radial velocities of - 1760 kms -1 (Nova Per) and - 1260 kms -1 (Nova Sct). Later, after the novae entered the nebular stage, the continuum weakened, the absorption disappeared and the novae displayed the usual emission spectrum, with permitted and forbidden lines of high excitation ([O III], N III, He I, He II). Forbidden lines of Fe VI and Fe VII - and in Nova Sct, also Fe X and A X - were present for a time, but they soon disappeared, so that at the end the spectrum was dominated by the [O III] nebular lines, even stronger than Hα. (Auth.)

  7. NUCLEAR MIXING METERS FOR CLASSICAL NOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Keegan J.; Iliadis, Christian; Downen, Lori; Champagne, Art [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255 (United States); José, Jordi [Departament de Física i Enginyeria Nuclear, EUETIB, Universitat Politècnica de Catalunya, E-08036 Barcelona (Spain)

    2013-11-10

    Classical novae are caused by mass transfer episodes from a main-sequence star onto a white dwarf via Roche lobe overflow. This material possesses angular momentum and forms an accretion disk around the white dwarf. Ultimately, a fraction of this material spirals in and piles up on the white dwarf surface under electron-degenerate conditions. The subsequently occurring thermonuclear runaway reaches hundreds of megakelvin and explosively ejects matter into the interstellar medium. The exact peak temperature strongly depends on the underlying white dwarf mass, the accreted mass and metallicity, and the initial white dwarf luminosity. Observations of elemental abundance enrichments in these classical nova events imply that the ejected matter consists not only of processed solar material from the main-sequence partner but also of material from the outer layers of the underlying white dwarf. This indicates that white dwarf and accreted matter mix prior to the thermonuclear runaway. The processes by which this mixing occurs require further investigation to be understood. In this work, we analyze elemental abundances ejected from hydrodynamic nova models in search of elemental abundance ratios that are useful indicators of the total amount of mixing. We identify the abundance ratios ΣCNO/H, Ne/H, Mg/H, Al/H, and Si/H as useful mixing meters in ONe novae. The impact of thermonuclear reaction rate uncertainties on the mixing meters is investigated using Monte Carlo post-processing network calculations with temperature-density evolutions of all mass zones computed by the hydrodynamic models. We find that the current uncertainties in the {sup 30}P(p, γ){sup 31}S rate influence the Si/H abundance ratio, but overall the mixing meters found here are robust against nuclear physics uncertainties. A comparison of our results with observations of ONe novae provides strong constraints for classical nova models.

  8. NSWEP: The Nova Scotia Wind Energy Project

    International Nuclear Information System (INIS)

    Hughes, L.; Little, T. A.

    2000-01-01

    A two-phase project, intended to educate Nova Scotians about the potential of wind power to help reduce the province's greenhouse gas emissions, thereby fulfilling a vital role in Canada's effort to mitigate climate change effects, is described. First phase of the project involves gathering of wind data; the second the installation of a number of wind turbines throughout the province. The data gathering phase encompasses site selection, the actual data gathering for a period of about ten months, data analysis, and creation of a four or five module educational program, to be linked with intermediate high school science, mathematics, geography and social studies curriculum objectives to provide an interdisciplinary examination of these topics, and convey a sense of the complexity of the issues involved. The second phase of the project is intended to promote the possible use of wind energy in the province by installing a number of 25 kW wind turbines at selected sites throughout the province, followed by the gathering analysis of data relating to the amount of power produced by the turbines, calculating the efficiency of turbines and comparing data with the data gathered in previous years. The project is expected to last at least five years, exposing about 4000 high school students to hands-on involvement with issues of climate change and sustainable energy. Parents and the community will be exposed to these same issues indirectly, aided by the relative proximity of the weather stations to schools and the strategic location of the wind turbines. 4 refs

  9. Uranium in Nova Scotia: a background summary for the uranium inquiry, Nova Scotia

    International Nuclear Information System (INIS)

    1982-01-01

    Since the mid 1970's Nova Scotia has experienced increased exploration for a number of commodities including uranium. The exploration activity for uranium has resulted in discovery of significant occurrences of the element. It became obvious to the Government of Nova Scotia that a segment of the population of the Province is concerned about the potential hazards associated with the exploration, mining and milling stages of the uranium industry. Public concern has resulted in the appointment of a Commissioner under the Public Inquiries Act of Nova Scotia to inquire and make recommendations to the Governor-in-Council on all aspects of exploration, development, mining, processing, storage, waste management and transportation of uranium in any form. The regulation of mineral exploration and mining activities is carried out by the Nova Scotia Department of Mines and Energy through the Mineral Resources Act of the Province of Nova Scotia. The regulation of the special radioactive aspects involved in the mining and processing of uranium ore is the responsibility of the federal Atomic Energy Control Board. The purposes of this report is to: outline the history of uranium exploration in Nova Scotia; summarize the results of geological surveys by provincial and federal government agencies, universities and exploration companies which document the natural levels of radioactivity in the Province; briefly outline the physical and chemical characteristics of uranium and thorium which make these elements unique and a potential environmental and health concern; outline chronologically the steps taken by the Nova Scotia Department of Mines and Energy to monitor and regulate uranium exploration activities; classify the types of uranium deposits known to occur in Nova Scotia and describe their main geological features; outline the role of the Nova Scotia Department of Mines and Energy in the regulation of mining activities in the Province. The report is written for the interested

  10. X-ray novae - what are they

    International Nuclear Information System (INIS)

    Wennfors, B.

    1976-01-01

    Ten of the two hundred cosmic X-ray sources exhibit characteristics in their emissions analogous to novae, i.e. after a rapid increase in luminosity, lasting about three days, follows a period of about a month with a slow decrease, and thereafter a rapid decrease to invisibility. The spectra of such sources are discussed in general terms and brief descriptions are given of the five which have been identified with optical objects. Three models for the history of X-ray novae, all based on X-ray emission from a compact object in an orbit very near a larger star, are discussed. (JIW)

  11. Eruptions and superhumps in dwarf novae

    International Nuclear Information System (INIS)

    Patterson, J.

    1979-01-01

    The existence of two distinct eruption types in dwarf novae is considered. A small subclass of dwarf novae, the SU Ursae Majoris stars, show occasional very bright and long eruptions (''supermaxima''), and during supermaxima, large-amplitude photometric variations (''superhumps'') at a period related to the orbital period are seen. Two new stars showing these effects, AY Lyrae and YZ Cancri, are reported. A third star, WZ Sagittae, is probably also a member of the class. Models for the superhumps are reviewed and found to be unsatisfactory. Observational constraints on a successful model are discussed

  12. Radio Observations of Gamma-ray Novae

    Science.gov (United States)

    Linford, Justin D.; Chomiuk, L.; Ribeiro, V.; project, E.-Nova

    2014-01-01

    Recent detection of gamma-ray emission from classical novae by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope surprised many in the astronomical community. We present results from radio observations, obtained using the Karl G. Jansky Very Large Array (VLA), of three gamma-ray novae: Mon2012, Sco2012, and Del2013. Radio observations allow for the calculation of ejecta masses, place limits on the distances, and provide information about the gamma-ray emission mechanism for these sources.

  13. Spectral evolution of dwarf nova outbursts

    International Nuclear Information System (INIS)

    Cannizzo, J.K.; Kenyon, S.J.

    1987-01-01

    The disk instability model for dwarf nova eruptions is investigated by computing the spectral development of the accretion disk through a complete limit cycle. Observed stellar spectra are used to model the radiation emitted by optically thick annuli within the disc. The general findings agree with those of Smak (1984) and Pringle et al. (1986). It is suggested that the dwarf nova oscillations might be a source of information concerning the evolution of the inner disk and that detailed observations of this phenomenon can be used to test various outburst mechanisms. 74 references

  14. Terra Nova breaks new ground for alliances

    International Nuclear Information System (INIS)

    Ghiselin, D.

    1996-01-01

    This paper reviews the development of alliances to help develop the Terra Nova oil and gas field in the offshore Atlantic areas of Canada. Largely attributed to BP, the strategic alliance concept got its start in the North Sea and on the North Slope of Alaska. BP saw it as the best way to take advantage of economy-of-scale, mitigate risk, and achieve outsourcing goals while retaining their core competencies. This paper reviews the methods of developing the alliances, the developing of a development plan for the Terra Nova field, and how the alliance plans to maximize the profittability of the operation for all involved

  15. Relationship of classical novae to other eruptive variables

    International Nuclear Information System (INIS)

    Vogt, N.

    1989-01-01

    Classical novae are characterized by their well known large-amplitude outbursts, accompanied by the ejection of a shell. The same stars, however, apparently pass through much longer quiescent phases whose duration exceeds that of the outburst phase by a factor ∼ 10 5 and that of historical nova records by a factor 10 2 -10 3 . Therefore a large number of variable stars should exist which actually are classical nova systems but whose last outbursts occurred in prehistoric times. We assume that some of these stars are hidden among the so-called 'nova-lies' in the literature. However some eruptive variables and symbiotic stars, i.e. stars which certainly are not nova remnants, are mentioned. Variables related to classical novae can be divided into three main classes: (i) Potential novae which are possibly classical novae in their quiescent state. Potential novae must share the basic configuration and parameters (orbital period, masses) with classical novae; they must be semi-detached cataclysmic binaries with a white dwarf as primary and a Roche-lobe-filling red dwarf on, or near, the mainsequence as secondary. (ii) Stars which share some outburst characteristics with classical novae without having the same binary configuration. For example recurrent novae with giant secondaries, very slow novae (and symbiotic binary stars). (iii) Stars which are evolutionarily related to classical novae, i.e. which possibly are progenitors or successors of novae in their secular evolution, such as binary nuclei of planetary nebulae and close, but detached, white dwarf-red dwarf pairs (e.g. V 471 Tau), both resulting from common-envelope evolution. These three main groups of nova-related stars are discussed. (author)

  16. Assurance management program for the 30 Nova laser fusion project

    International Nuclear Information System (INIS)

    Levy, A.J.

    1983-01-01

    The Nova assurance management program was developed using the quality assurance (QA) approach first implemented at LLNL in early 1978. The LLNL QA program is described as an introduction to the Nova assurance management program. The Nova system is described pictorially through the Nova configuration, subsystems and major components, interjecting the QA techniques which are being pragmatically used to assure the successful completion of the project

  17. An Emerging Wine Region in Nova Scotia, Canada: Terroir Trials and Tribulations

    Science.gov (United States)

    Cameron, B. I.; Ketter, B. S.; Karakis, S.

    2012-12-01

    loams. In the Gaspereaux Valley, a sub-valley of the Annapolis Valley, relatively fertile silty and clay loams dominate on the south-facing slope, but well-drained, gravel-rich glacial soils on the north-facing slope impart a complex and mineral flavor profile to the wines. Detailed soil profiles from select vineyards along with studies of soil texture and chemistry highlight differences in terroirs in the four wine regions. This terroir study assists the expanding, but young wine industry in Nova Scotia to ideally match grape variety to vineyard block.

  18. SN 2010U: A LUMINOUS NOVA IN NGC 4214

    International Nuclear Information System (INIS)

    Humphreys, Roberta M.; Helton, L. Andrew; Prieto, Jose L.; Rosenfield, Philip; Williams, Benjamin; Murphy, Jeremiah; Dalcanton, Julianne; Gilbert, Karoline; Kochanek, Christopher S.; Stanek, K. Z.; Khan, Rubab; Szczygiel, Dorota; Mogren, Karen; Fesen, Robert A.; Milisavljevic, Dan

    2010-01-01

    The luminosity, light curve, post-maximum spectrum, and lack of a progenitor on deep pre-outburst images suggest that SN 2010U was a luminous, fast nova. Its outburst magnitude is consistent with that for a fast nova using the maximum magnitude-rate of decline relationship for classical novae.

  19. Neutron capture measurements on 62Ni, 63Ni and 197Au and their relevance for stellar nucleosynthesis

    CERN Document Server

    Lederer, Claudia

    Neutron capture reactions in stars are responsible for forming about 99% of the elemental abundances heavier than Fe. Two processes contribute about equally to the overall abundance pattern: the slow neutron capture process (s process) where neutron densities are small and therefore radioactive decay is generally faster than subsequent neutron capture on radionuclides, and the rapid neutron capture process (r process) which takes place in environments of high neutron densities, driving the reaction path towards the neutron rich side. The key nuclear physics input for s process studies are stellar neutron capture cross sections, called MACS (Maxwellian-averaged cross section). In the course of this work, dierent reactions relevant to s process nucleosynthesis have been studied. To improve and check existing information, neutron capture cross sections of most stable Fe and Ni isotopes were measured via the time-of-flight technique at the n TOF facility at CERN. This campaign was triggered by a work of Sneden et...

  20. NOVA making stuff: Season 2

    Energy Technology Data Exchange (ETDEWEB)

    Leombruni, Lisa [WGBH Educational Foundation, Boston, MA (United States); Paulsen, Christine Andrews [Concord Evaluation Group, Concord, MA (United States)

    2014-12-12

    Over the course of four weeks in fall 2013, 11.7 million Americans tuned in to PBS to follow host David Pogue as he led them in search of engineering and scientific breakthroughs poised to change our world. Levitating trains, quantum computers, robotic bees, and bomb-detecting plants—these were just a few of the cutting-edge innovations brought into the living rooms of families across the country in NOVA’s four-part series, Making Stuff: Faster, Wilder, Colder, and Safer. Each of the four one-hour programs gave viewers a behind-the-scenes look at novel technologies poised to change our world—showing them how basic research and scientific discovery can hold the keys to transforming how we live. Making Stuff Season 2 (MS2) combined true entertainment with educational value, creating a popular and engaging series that brought accessible science into the homes of millions. NOVA’s goal to engage the public with such technological innovation and basic research extended beyond the broadcast series, including a variety of online, educational, and promotional activities: original online science reporting, web-only short-form videos, a new online quiz-game, social media engagement and promotion, an educational outreach “toolkit” for science educators to create their own “makerspaces,” an online community of practice, a series of nationwide Innovation Cafés, educator professional development, a suite of teacher resources, an “Idealab,” participation in national conferences, and specialized station relation and marketing. A summative evaluation of the MS2 project indicates that overall, these activities helped make a significant impact on the viewers, users, and participants that NOVA reached. The final evaluation conducted by Concord Evaluation Group (CEG) confidently concluded that the broadcast, website, and outreach activities were successful at achieving the project’s intended impacts. CEG reported that the MS2 series and website content were

  1. Nucleosynthesis in Wolf-Rayet stars and galactic cosmic-ray isotopic composition

    International Nuclear Information System (INIS)

    Prantzos, N.

    1984-01-01

    An explanation of the isotopic composition of galactic cosmic rays could provide some clues to the mystery of their origin. It seems now that the strong stellar winds of Wolf-Rayet stars could account for most of the isotopic anomalies that have been observed in cosmic rays. Some results are presented, obtained by detailed nucleosynthesis computations. 25 references

  2. Abundances of La and Ta Through ν-Nucleosynthesis in 20M ...

    Indian Academy of Sciences (India)

    Solar mass fractions of the seeds La139, Ta181, Ba138 and Hf180 are taken for calculation. They are assumed to be produced in ... of these elements by extending the earlier works on neutrino nucleosynthesis in massive stars. .... ing the shock heating of the layers surrounding the collapsing core of supernova progenitor.

  3. CIRCUMSTELLAR SHELL FORMATION IN SYMBIOTIC RECURRENT NOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Kevin; Bildsten, Lars [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106 (United States)

    2012-12-20

    We present models of spherically symmetric recurrent nova shells interacting with circumstellar material (CSM) in a symbiotic system composed of a red giant (RG) expelling a wind and a white dwarf accreting from this material. Recurrent nova eruptions periodically eject material at high velocities ({approx}> 10{sup 3} km s{sup -1}) into the RG wind profile, creating a decelerating shock wave as CSM is swept up. High CSM densities cause the shocked wind and ejecta to have very short cooling times of days to weeks. Thus, the late-time evolution of the shell is determined by momentum conservation instead of energy conservation. We compute and show evolutionary tracks of shell deceleration, as well as post-shock structure. After sweeping up all the RG wind, the shell coasts at a velocity {approx}100 km s{sup -1}, depending on system parameters. These velocities are similar to those measured in blueshifted CSM from the symbiotic nova RS Oph, as well as a few Type Ia supernovae that show evidence of CSM, such as 2006X, 2007le, and PTF 11kx. Supernovae occurring in such systems may not show CSM interaction until the inner nova shell gets hit by the supernova ejecta, days to months after the explosion.

  4. High density implosion experiments at Nova

    International Nuclear Information System (INIS)

    Cable, M.D.; Hatchett, S.P.; Nelson, M.B.; Lerche, R.A.; Murphy, T.J.; Ress, D.B.

    1994-01-01

    Deuterium filled glass microballoons are used as indirectly driven targets for implosion experiments at the Nova Laser Fusion Facility. High levels of laser precision were required to achieve fuel densities and convergences to an ignition scale hot spot. (AIP) copyright 1994 American Institute of Physics

  5. Nova performance at ultra high fluence levels

    International Nuclear Information System (INIS)

    Hunt, J.T.

    1986-01-01

    Nova is a ten beam high power Nd:glass laser used for interial confinement fusion research. It was operated in the high power high energy regime following the completion of construction in December 1984. During this period several interesting nonlinear optical phenomena were observed. These phenomena are discussed in the text. 11 refs., 5 figs

  6. NOVA[R] Spring 2002 Teacher's Guide.

    Science.gov (United States)

    Armstrong, Peter; Ransick, Kristi; Rosene, Dale; Sammons, James

    The guide presents lesson plans from "NOVA" which targets middle school and junior high school students and meet the National Science Education Standards. Lessons include: (1) "Neanderthals on Trial"; (2) "Fireworks"; (3) "Secrets, Lies and Atomic Spies"; (4) "Bioterror"; (5) "The Missing…

  7. ULF fluctuations at Terra Nova Bay (Antarctica

    Directory of Open Access Journals (Sweden)

    A. Meloni

    2000-06-01

    Full Text Available ULF geomagnetic field measurements in Antarctica are a very important tool for better understanding the dynamics of the Earth’s magnetosphere and its response to the variable solar wind conditions. We review the results obtained in the last few years at the Italian observatory at Terra Nova Bay

  8. Nova pulse power system description and status

    International Nuclear Information System (INIS)

    Holloway, R.W.; Whitham, K.; Merritt, B.T.; Gritton, D.G.; Oicles, J.A.

    1981-01-01

    The Nova laser system is designed to produce critical data in the nation's inertial confinement fusion effort. It is the world's largest peak power laser and presents various unique pulse power problems. In this paper, pulse power systems for this laser are described, the evolutionary points from prior systems are pointed out, and the current status of the hardware is given

  9. Precision Mass Measurements of 129-131Cd and Their Impact on Stellar Nucleosynthesis via the Rapid Neutron Capture Process

    CERN Document Server

    Atanasov, D.; Blaum, K.; Cakirli, R.B.; Cocolios, T.E.; George, S.; Herfurth, F.; Kisler, D.; Janka, H.T.; Just, O.; Kowalska, M.; Kreim, S.; Kisler, D.; Litvinov, Yu. A.; Lunney, D.; Manea, V.; Neidherr, D.; Rosenbusch, M.; Schweikhard, L.; Welker, A.; Wienholtz, F.; Wolf, R. N.; Zuber, K.

    2015-01-01

    Masses adjacent to the classical waiting-point nuclide 130Cd have been measured by using the Penning- trap spectrometer ISOLTRAP at ISOLDE/CERN. We find a significant deviation of over 400 keV from earlier values evaluated by using nuclear beta-decay data. The new measurements show the reduction of the N = 82 shell gap below the doubly magic 132Sn. The nucleosynthesis associated with the ejected wind from type-II supernovae as well as from compact object binary mergers is studied, by using state-of-the-art hydrodynamic simulations. We find a consistent and direct impact of the newly measured masses on the calculated abundances in the A = 128 - 132 region and a reduction of the uncertainties from the precision mass input data.

  10. Theory of Nova Outbursts and Type Ia Supernovae

    Directory of Open Access Journals (Sweden)

    M. Kato

    2015-02-01

    Full Text Available We briefly review the current theoretical understanding of the light curves of novae. These curves exhibit a homologous nature, dubbed the universal decline law, and when time-normalized, they almost follow a single curve independently of the white dwarf (WD mass or chemical composition of the envelope. The optical and near-infrared light curves of novae are reproduced mainly by free-free emission from their optically thick winds. We can estimate the WD mass from multiwavelength observations because the optical, UV, and soft X-ray light curves evolve differently and we can easily resolve the degeneracy of the optical light curves. Recurrent novae and classical novae are a testbed of type Ia supernova scenarios. In the orbital period versus secondary mass diagram, recurrent novae are located in different regions from classical novae and the positions of recurrent novae are consistent with the single degenerate scenario.

  11. Indirect Measurement of 15N(p,α)12C and 18O(p,α)15N. Applications to the AGB Star Nucleosynthesis

    International Nuclear Information System (INIS)

    La Cognata, M.; Spitaleri, C.; Cherubini, S.; Crucilla, V.; Gulino, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tumino, A.; Tribble, R.; Al-Abdullah, T.; Banu, A.; Fu, C.; Goldberg, V.; Mukhamedzhanov, A.; Tabacaru, G.; Trache, L.

    2008-01-01

    The Trojan Horse Method has been recently applied to the study of reactions involved in fluorine nucleosynthesis inside AGB stars. Fluorine abundance is important since it allows to constrain mixing models from the comparison of the observed fluorine abundances with the ones predicted by models. Anyway direct measurements of the cross section do not extend down to the Gamow peak, which is the astrophysically relevant energy region. In particular the study focuses on the 15 N(p,α) 12 C and the 18 O(p,α) 15 N reactions which can influence fluorine yield as they are part of 19 F production/destruction network

  12. Cosmological nucleosynthesis and active-sterile neutrino oscillations with small mass differences: the nonresonant case

    International Nuclear Information System (INIS)

    Kirilova, D.P.; Chizhov, M.V.

    1998-05-01

    We study the nonresonant oscillations between left-handed electron neutrinos ν s and nonthermalized sterile neutrinos ν s in the early Universe plasma. The case when ν s do not thermalize till 2 MeV and the oscillations become effective after ν e decoupling is discussed. As far as for this model the rates of expansion of the Universe, neutrino oscillations and neutrino interactions with the medium may be comparable, we have analyzed the kinetic equations for neutrino density matrix, accounting simultaneously for these processes. The evolution of neutrino ensembles was described numerically by integrating the kinetic equations for the neutrino density matrix in momentum space for small mass differences δm 2 ≤10 -7 eV 2 . This approach allowed us to study precisely the evolution of the neutrino number densities, energy spectrum distortion and the asymmetry between neutrinos and antineutrinos due to oscillations for each momentum mode. We have performed a complete numerical analysis for the full range of the oscillations parameters of the model of the influence of the nonequilibrium ν e ↔ν s oscillations on the primordial production of 4 He. The exact kinetic approach enabled us to calculate the effects of neutrino population depletion, the distortion of the neutrino spectrum and the generation of neutrino-antineutrino asymmetry on the kinetics of neutron-to-proton transitions during the primordial nucleosynthesis epoch and correspondingly on the cosmological 4 He production. It was shown that the neutrino population depletion and spectrum distortion play an important role. The asymmetry effect, in case the lepton asymmetry is accepted initially equal to the baryon one, is proved to be negligible for the discussed range of δm 2 . Constant helium contours in δm 2 -θ plane were calculated. Thanks to the exact kinetic approach more precise cosmological constraints on the mixing parameters were obtained. (author)

  13. Pygmy and core polarization dipole modes in 206Pb: Connecting nuclear structure to stellar nucleosynthesis

    Science.gov (United States)

    Tonchev, A. P.; Tsoneva, N.; Bhatia, C.; Arnold, C. W.; Goriely, S.; Hammond, S. L.; Kelley, J. H.; Kwan, E.; Lenske, H.; Piekarewicz, J.; Raut, R.; Rusev, G.; Shizuma, T.; Tornow, W.

    2017-10-01

    A high-resolution study of the electromagnetic response of 206Pb below the neutron separation energy is performed using a (γ → ,γ‧) experiment at the HI γ → S facility. Nuclear resonance fluorescence with 100% linearly polarized photon beams is used to measure spins, parities, branching ratios, and decay widths of excited states in 206Pb from 4.9 to 8.1 MeV. The extracted ΣB (E 1) ↑ and ΣB (M 1) ↑ values for the total electric and magnetic dipole strength below the neutron separation energy are 0.9 ± 0.2 e2fm2 and 8.3 ± 2.0 μN2, respectively. These measurements are found to be in very good agreement with the predictions from an energy-density functional (EDF) plus quasiparticle phonon model (QPM). Such a detailed theoretical analysis allows to separate the pygmy dipole resonance from both the tail of the giant dipole resonance and multi-phonon excitations. Combined with earlier photonuclear experiments above the neutron separation energy, one extracts a value for the electric dipole polarizability of 206Pb of αD = 122 ± 10 mb /MeV. When compared to predictions from both the EDF+QPM and accurately calibrated relativistic EDFs, one deduces a range for the neutron-skin thickness of Rskin206 = 0.12- 0.19 fm and a corresponding range for the slope of the symmetry energy of L = 48- 60 MeV. This newly obtained information is also used to estimate the Maxwellian-averaged radiative cross section 205Pb (n , γ)206Pb at 30 keV to be σ = 130 ± 25 mb. The astrophysical impact of this measurement-on both the s-process in stellar nucleosynthesis and on the equation of state of neutron-rich matter-is discussed.

  14. Evolution and nucleosynthesis of asymptotic giant branch stellar models of low metallicity

    Energy Technology Data Exchange (ETDEWEB)

    Fishlock, Cherie K.; Karakas, Amanda I.; Yong, David [Research School of Astronomy and Astrophysics, Australian National University, Canberra ACT 2611 (Australia); Lugaro, Maria, E-mail: cherie.fishlock@anu.edu.au, E-mail: amanda.karakas@anu.edu.au, E-mail: david.yong@anu.edu.au, E-mail: maria.lugaro@monash.edu [Monash Centre for Astrophysics, Monash University, Clayton VIC 3800 (Australia)

    2014-12-10

    We present stellar evolutionary tracks and nucleosynthetic predictions for a grid of stellar models of low- and intermediate-mass asymptotic giant branch (AGB) stars at Z = 0.001 ([Fe/H] =–1.2). The models cover an initial mass range from 1 M {sub ☉} to 7 M {sub ☉}. Final surface abundances and stellar yields are calculated for all elements from hydrogen to bismuth as well as isotopes up to the iron group. We present the first study of neutron-capture nucleosynthesis in intermediate-mass AGB models, including a super-AGB model, of [Fe/H] = –1.2. We examine in detail a low-mass AGB model of 2 M {sub ☉} where the {sup 13}C(α,n){sup 16}O reaction is the main source of neutrons. We also examine an intermediate-mass AGB model of 5 M {sub ☉} where intershell temperatures are high enough to activate the {sup 22}Ne neutron source, which produces high neutron densities up to ∼10{sup 14} n cm{sup –3}. Hot bottom burning is activated in models with M ≥ 3 M {sub ☉}. With the 3 M {sub ☉} model, we investigate the effect of varying the extent in mass of the region where protons are mixed from the envelope into the intershell at the deepest extent of each third dredge-up. We compare the results of the low-mass models to three post-AGB stars with a metallicity of [Fe/H] ≅ – 1.2. The composition is a good match to the predicted neutron-capture abundances except for Pb and we confirm that the observed Pb abundances are lower than what is calculated by AGB models.

  15. Cosmic-Ray Nucleosynthesis of p-nuclei: Yields and Routes

    Science.gov (United States)

    Kusakabe, Motohiko; Mathews, Grant J.

    2018-02-01

    We investigate the cosmic-ray nucleosynthesis (CRN) of proton-rich stable nuclides (p-nuclides). We calculate the cosmic-ray (CR) energy spectra of heavy nuclides with mass number A=[74,209], taking into account the detailed nuclear spallation, decay, energy loss, and escape from the Galaxy during the CR propagation. We adopt the latest semiempirical formula SPACS for the spallation cross sections and the latest data on nuclear decay. Effective electron-capture decay rates are calculated using the proper cross sections for recombination and ionization in the whole CR energy region. Calculated CR spectral shapes vary for different nuclides. Abundances of proton-rich unstable nuclides increase in CRs with increasing energy relative to those of other nuclides. Yields of the primary and secondary spallation processes and differential yields from respective seed nuclides are calculated. We find that the CR energy region of ≤slant { \\mathcal O }(100) MeV/nucleon predominantly contributes to the total yields. The atomic cross sections in the low-energy range adopted in this study are then necessary. Effects of CRN on the Galactic chemical evolution of p-nuclides are calculated. Important seed nuclides are identified for respective p-nuclides. The contribution of CRN is significant for 180m Ta, accounting for about 20% of the solar abundance. About 87% of the 180m Ta CRN yield can be attributed to the primary process. The most important production routes are reactions of 181Ta, 180Hf, and 182W. CRN yields of other p-nuclides are typically about { \\mathcal O }(10‑4–10‑2) of solar abundances.

  16. Spectroscopic observations of Nova Cygni 1975: The coronal line region revisited

    International Nuclear Information System (INIS)

    Ferland, G.J.; Lambert, D.L.; Woodman, J.H.

    1986-01-01

    A synopsis of the McDonald Observatory spectrophotometric observations of Nova Cyg 1975 (V1500 Cyg) is presented. We present these data in a form in which they can be readily accessed in the future, and also study the continous spectrum during the early nebular phase. We show that (1) the remnant probably maintained a luminosity at or above the Eddington limit for at least a year after outburst, (2) free-free emission from the coronal line region made a significant contribution to the optical continuum, and (3) the coronal line region was probably a significant source of ionizing radiation. The energetics of this nova appear to be dominated by the lift-off energy from the white dwarf and radiation from the coronal line region. Thus the light curve of Nova Cyg may tell more about the cooling of the coronal line region than about the decline of the central object. In appendices we discuss the argon abundance of Nova Cyg (less than 8 times solar) and describe how to obtain copies of the McDonald nova data

  17. V2487 Oph 1998: a post nova in an intermediate polar

    Directory of Open Access Journals (Sweden)

    Hernanz Margarita

    2014-01-01

    Full Text Available V2487 Oph (Nova Oph 1998 is a classical nova that exploded in 1998. XMM-Newton observations performed between 2 and 9 years after the explosion showed emission related to restablished accretion, and indicative of a magnetic white dwarf. The spectrum looks like that of a cataclysmic variable of the intermediate polar type. Anyway, we don’t have yet a definitive confirmation of the intermediate polar character, through determination of spin and orbital periods. Although it is not the first nova exploding in a magnetic white dwarf, it is always challenging to reach explosive conditions when a standard accretion disk can’t be formed, because of the magnetic field. In addition, V2487 Oph has been the first nova where a detection of X-rays - in the host binary system – has been reported prior to its eruption, in 1990 with the ROSAT satellite. V2487 Oph has been also detected in hard X-rays with INTEGRAL/IBIS and RXTE/PCA. Last but not least, V2487 Oph has been identified as a recurrent nova in 2008, since a prior eruption in 1900 has been reported through analysis of Harvard photographic plates. Therefore, it is expected to host a massive white dwarf and be a candidate for a type Ia supernova explosion. In a recent study of the progenitors of galactic novae, it has been emphasized that V2487 Oph is an important and interesting object, "intermediate" between the "standard" classical novae and other historical and well-known recurrent novae with shorter recurrence periods. It could be that in the end there’s a continuous distribution of recurrence periods, instead of the common understanding up to now that "classical" and "recurrent" novae were quite apart (with recurrence periods of more than 104 years and less than 100years - approximately - respectively. We present the results of our campaign of several observations with XMM-Newton. The consequences for the understanding of such a puzzling object are discussed.

  18. Neutrino Oscillation Results from NOvA

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    NOvA is an accelerator long-baseline neutrino oscillation experiment optimised to measure electron neutrino appearance in a high-purity beam of muon neutrinos from Fermilab. The exciting discovery of the theta13 neutrino mixing angle in 2012 has opened a door to making multiple new measurements of neutrinos. These include leptonic CP violation, the neutrino mass ordering and the octant of theta23. NOvA with its 810km baseline and higher energy beam has about triple the matter effect of T2K which opens a new window on the neutrino mass ordering. With about 20% of our design beam exposure and significant analysis improvements we have recently released updated results. I will present both our disappearance and appearance measurements.

  19. Tracking the NOvA Detectors' Performance

    Science.gov (United States)

    Psihas, Fernanda; NOvA Collaboration

    2016-03-01

    The NOvA experiment measures long baseline νμ -->νe oscillations in Fermilab's NuMI beam. We employ two detectors equipped with over 10 thousand sets of data-taking electronics; avalanche photo diodes and front end boards which collect and process the scintillation signal from particle interactions within the detectors. These sets of electronics -as well as the systems which power and cool them- must be monitored and maintained at precise working conditions to ensure maximal data-taking uptime, good data quality and a lasting life for our detectors. This poster describes the automated systems used on NOvA to simultaneously monitor our data quality, diagnose hardware issues, track our performance and coordinate maintenance for the detectors.

  20. Perspective : component tracking on the Nova system

    International Nuclear Information System (INIS)

    MacDonald, S.

    1999-01-01

    The issue of introducing Component Tracking as a service to natural gas producers, shippers and straddle plant operators was discussed. Approximately 39 companies in the industry were contacted by consultants at Nova Gas Transmission in an effort to assess if introducing this service would add value to individual producers. The numerous implications that may have to be dealt with if Component Tracking is introduced were also described. Component Tracking would provide an equitable approach to the allocation of molecules in the gas stream, and could provide producers with the ability to avoid capital outlay in field plants by alternatively contracting for recovery of the liquids at the straddle plants. Component Tracking is to be voluntary and each shipper would be able to decide whether to utilize the service at each of their receipt points onto the Nova system

  1. A wave model for dwarf novae

    International Nuclear Information System (INIS)

    Sparks, W.M.; Kutter, G.S.

    1980-01-01

    The rapid coherent oscillation during a dwarf nova outburst is attributed to an accretion-driven wave going around the white dwarf component of the binary system. The increase and decrease in the period of this oscillation is due to the change in the velocity of the wave as it is first being driven and then damped. Qualitatively, a large number of observations can be explained with such a model. The beginnings of a mathematical representation of this model are developed. (orig.)

  2. Swift observations of Nova Scuti 2017

    Science.gov (United States)

    Kuin, N. P. M.; Page, K. L.; Williams, S. C.; Darnley, M. J.; Nelson, T. J.; Osborne, J.

    2017-08-01

    Nova Sct 2017 (ASASSN-17hx/ASASSN-17ib) went into eruption on 2017-06-19.41 (hereafter taken as Day 0), as reported on the ASAS SN transient page (see also ATEL #10523,#10524) Spectroscopic confirmation (ATEL #10527,#10542) observed emission in H and He I, and in N II as well as Fe II. The ASASSN light curve data show a peak of V = 8.75 on 2017, July 30, day 40.867.

  3. A NOVA EVANGELIZAÇÃO NA EUROPA

    Directory of Open Access Journals (Sweden)

    Martin Maier

    2013-01-01

    Full Text Available Neste estudo, o olhar dirige-se em primeiro lugar para a situação religiosa da Europa. Em seguida, resumiremos o conceito da nova evangelização de acordo com os últimos papas. O passo seguinte será perguntar o que as igrejas podem oferecer à Europa. A nova evangelização deve acontecer no horizonte do ecumenismo e da globalização. Importante ponto de conexão para a transmissão da fé é a constante sede de espiritualidade e de experiência espiritual, bem como de conhecimento da religião e da fé. Por fim, desenvolveremos algumas chances que podem relacionar-se com a nova evangelização na Europa.  ABSTRACT: In this study, the focus is directed first of ali to the religious situation in Europe. Then we will sum up the concept of the new evangelization according to the recent Popes. The next step will be to ask what the churches can offer to Europe. The new evangelization must happen on the horizon of ecumenism and globalization. An important point of connection to the transmission of the faith is the constant thirst for spirituality and spiritual experience as well as the knowledge of religion and faith. Finally, we will develop some opportunities that can relate to the new evangelization in Europe

  4. Nova Scotia Resources Limited annual report, 1992

    International Nuclear Information System (INIS)

    1992-01-01

    Nova Scotia Resources was established in 1981 by the provincial government to invest in and manage Nova Scotia's participation in petroleum, energy, and mineral development. The company and its subsidiaries hold interests in oil and gas discovery areas and producing fields in the Nova Scotia offshore, and owns producing oil and gas interests in western Canada. In June 1992, oil production began from the Cohasset project, representing Canada's first commercial offshore oil production. Nearly 4 million bbl of crude will be sold in the first production season. Work is continuing on additional producing wells; the production life of the Cohasset project is currently estimated at 6 y. Offshore exploration activity is also continuing under four exploration licenses. For the 12 months ending March 31, 1992, net earnings from western oil and gas production were $369,000. Total gross revenues from oil and gas producing properties for the year were ca $4.8 million. Other 1992 activities include active exploration for salt and potash sites with potential for underground storage of natural gas. Financial statements are included. 14 figs., 2 tabs

  5. IMPACT OF NEW GAMOW–TELLER STRENGTHS ON EXPLOSIVE TYPE IA SUPERNOVA NUCLEOSYNTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Kanji; Famiano, Michael A.; Kajino, Toshitaka; Suzuki, Toshio [National Astronomical Observatory of Japan 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Hidaka, Jun [Mechanical Engineering Department, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo 191-8506 (Japan); Honma, Michio [Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, Fukushima 965-8580 (Japan); Iwamoto, Koichi [Department of Physics, College of Science and Technology, Nihon University, Tokyo 101-8308 (Japan); Nomoto, Ken’ichi [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Otsuka, Takaharu, E-mail: kanji.mori@nao.ac.jp, E-mail: kajino@nao.ac.jp, E-mail: michael.famiano@wmich.edu, E-mail: suzuki@phys.chs.nihon-u.ac.jp, E-mail: jun.hidaka@meisei-u.ac.jp, E-mail: m-honma@u-aizu.ac.jp, E-mail: iwamoto@phys.cst.nihon-u.ac.jp, E-mail: nomoto@astron.s.u-tokyo.ac.jp, E-mail: otsuka@phys.s.u-tokyo.ac.jp [Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2016-12-20

    Recent experimental results have confirmed a possible reduction in the Gamow–Teller (GT{sub +}) strengths of pf-shell nuclei. These proton-rich nuclei are of relevance in the deflagration and explosive burning phases of SNe Ia. While prior GT strengths result in nucleosynthesis predictions with a lower-than-expected electron fraction, a reduction in the GT{sub +} strength can result in a slightly increased electron fraction compared to previous shell model predictions, though the enhancement is not as large as previous enhancements in going from rates computed by Fuller, Fowler, and Newman based on an independent particle model. A shell model parametrization has been developed that more closely matches experimental GT strengths. The resultant electron-capture rates are used in nucleosynthesis calculations for carbon deflagration and explosion phases of SNe Ia, and the final mass fractions are compared to those obtained using more commonly used rates.

  6. Big bang nucleosynthesis: The strong nuclear force meets the weak anthropic principle

    International Nuclear Information System (INIS)

    MacDonald, J.; Mullan, D. J.

    2009-01-01

    Contrary to a common argument that a small increase in the strength of the strong force would lead to destruction of all hydrogen in the big bang due to binding of the diproton and the dineutron with a catastrophic impact on life as we know it, we show that provided the increase in strong force coupling constant is less than about 50% substantial amounts of hydrogen remain. The reason is that an increase in strong force strength leads to tighter binding of the deuteron, permitting nucleosynthesis to occur earlier in the big bang at higher temperature than in the standard big bang. Photodestruction of the less tightly bound diproton and dineutron delays their production to after the bulk of nucleosynthesis is complete. The decay of the diproton can, however, lead to relatively large abundances of deuterium.

  7. Astrophysical Li-7 as a product of big bang nucleosynthesis and galactic cosmic-ray spallation

    Science.gov (United States)

    Olive, Keith A.; Schramm, David N.

    1992-01-01

    The astrophysical Li-7 abundance is considered to be largely primordial, while the Be and B abundances are thought to be due to galactic cosmic ray (GCR) spallation reactions on top of a much smaller big bang component. But GCR spallation should also produce Li-7. As a consistency check on the combination of big bang nucleosynthesis and GCR spallation, the Be and B data from a sample of hot population II stars is used to subtract from the measured Li-7 abundance an estimate of the amount generated by GCR spallation for each star in the sample, and then to add to this baseline an estimate of the metallicity-dependent augmentation of Li-7 due to spallation. The singly reduced primordial Li-7 abundance is still consistent with big bang nucleosynthesis, and a single GCR spallation model can fit the Be, B, and corrected Li-7 abundances for all the stars in the sample.

  8. Neutrino masses and mixings: Big Bang and Supernova nucleosynthesis and neutrino dark matter

    International Nuclear Information System (INIS)

    Fuller, George M.

    1999-01-01

    The existence of small mixings between light active and sterile neutrino species could have implications for Big Bang and Supernova Heavy Element Nucleosynthesis. As well, such mixing would force us to abandon cherished constraints on light neutrino Dark Matter. Two proposed 4-neutrino mass and mixing schemes, for example, can both accomodate existing experimental results and lead to elegant solutions to the neutron-deficit problem for r-Process nucleosynthesis from neutrino-heated supernova ejecta. Each of these solutions is based on matter-enhanced (MSW) active-sterile neutrino transformation. In plausible extensions of these schemes to the early universe, Shi and Fuller have shown that relatively light mass (∼200 eV to ∼10 keV) sterile neutrinos produced via active-sterile MSW conversion can have a ''cold'' energy spectrum. Neutrinos produced in this way circumvent the principal problem of light neutrino dark matter and would be, essentially, Cold Dark Matter

  9. Low-energy photodisintegration of the deuteron and Big-Bang nucleosynthesis

    International Nuclear Information System (INIS)

    Tornow, W.; Czakon, N.G.; Howell, C.R.; Hutcheson, A.; Kelley, J.H.; Litvinenko, V.N.; Mikhailov, S.F.; Pinayev, I.V.; Weisel, G.J.; Witala, H.

    2003-01-01

    The photon analyzing power for the photodisintegration of the deuteron was measured for seven gamma-ray energies between 2.39 and 4.05 MeV using the linearly polarized gamma-ray beam of the high-intensity gamma-ray source at the Duke Free-Electron Laser Laboratory. The data provide a stringent test of theoretical calculations for the inverse reaction, the neutron-proton radiative capture reaction at energies important for Big-Bang nucleosynthesis. Our data are in excellent agreement with potential model and effective field theory calculations. Therefore, the uncertainty in the baryon density Ω B h 2 obtained from Big-Bang Nucleosynthesis can be reduced at least by 20%

  10. Low-energy photodisintegration of the deuteron and Big-Bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Tornow, W.; Czakon, N.G.; Howell, C.R.; Hutcheson, A.; Kelley, J.H.; Litvinenko, V.N.; Mikhailov, S.F.; Pinayev, I.V.; Weisel, G.J.; Witala, H

    2003-11-06

    The photon analyzing power for the photodisintegration of the deuteron was measured for seven gamma-ray energies between 2.39 and 4.05 MeV using the linearly polarized gamma-ray beam of the high-intensity gamma-ray source at the Duke Free-Electron Laser Laboratory. The data provide a stringent test of theoretical calculations for the inverse reaction, the neutron-proton radiative capture reaction at energies important for Big-Bang nucleosynthesis. Our data are in excellent agreement with potential model and effective field theory calculations. Therefore, the uncertainty in the baryon density {omega}{sub B}h{sup 2} obtained from Big-Bang Nucleosynthesis can be reduced at least by 20%.

  11. Restablished Accretion in Post-outburst Classical Novae Revealed by X-rays

    Science.gov (United States)

    Hernanz, Margarita; Ferri, Carlo; Sala, Glòria

    2009-05-01

    Classical novae are explosions on accreting white dwarfs (hereinafter WDs) in cataclysmic variables (hereinafter CVs) a hydrogen thermonuclear runaway on top of the WD is responsible for the outburst. X-rays provide a unique way to study the turn-off of H-burning, because super soft X-rays reveal the hot WD photosphere, but also to understand how accretion is established again in the binary system. Observations with XMM-Newton of some post-outburst novae have revealed such a process, but a coverage up to larger energies -as Simbol-X will provide- is fundamental to well understand the characteristics of the binary system and of the nova ejecta. We present a brief summary of our results up to now and prospects for the Simbol-X mission.

  12. The Convolutional Visual Network for Identification and Reconstruction of NOvA Events

    Energy Technology Data Exchange (ETDEWEB)

    Psihas, Fernanda [Indiana U.

    2017-11-22

    In 2016 the NOvA experiment released results for the observation of oscillations in the vμ and ve channels as well as ve cross section measurements using neutrinos from Fermilab’s NuMI beam. These and other measurements in progress rely on the accurate identification and reconstruction of the neutrino flavor and energy recorded by our detectors. This presentation describes the first application of convolutional neural network technology for event identification and reconstruction in particle detectors like NOvA. The Convolutional Visual Network (CVN) Algorithm was developed for identification, categorization, and reconstruction of NOvA events. It increased the selection efficiency of the ve appearance signal by 40% and studies show potential impact to the vμ disappearance analysis.

  13. Large-basis shell-model technology in nucleosynthesis and cosmology

    International Nuclear Information System (INIS)

    Mathews, G.J.; Bloom, S.D.; Takahashi, K.; Fuller, G.M.; Hausman, R.F. Jr.

    1985-05-01

    We discuss various applications of the Lanczos method to describe properties of many-body microscopic systems in nucleosynthesis and cosmology. These calculations include: solar neutrino detectors; beta-decay of excited nuclear states; electron-capture rates during a core-bounce supernova; exotic quarked nuclei as a catalyst for hydrogen burning; and the quark-hadron phase transition during the early universe. 27 refs., 3 figs

  14. Distortions in the cosmic background radiation and big-bang 4He nucleosynthesis

    International Nuclear Information System (INIS)

    Mathews, G.J.; Alhassid, Y.; Fuller, G.M.

    1981-01-01

    The observed distortion of the cosmic background radiation is analyzed in the framework of information theory to derive a simple form of the photon occupation probability. Taking this distribution function as indicative of the Lagrange parameters which might characterize the era of nucleosynthesis during the big bang, and assuming equilibrium among the constituents present, we find that the primordial 4 He abundance may be reduced by as much as 15% from the standard big-bang prediction

  15. Lithium isotopic abundances in metal-poor stars: a problem for standard big bang nucleosynthesis?

    International Nuclear Information System (INIS)

    Nissen, P.E.; Asplund, M.; Lambert, D.L.; Primas, F.; Smith, V.V.

    2005-01-01

    Spectral obtained with VLT/UVES suggest the existence of the 6 Li isotope in several metal-poor stars at a level that challenges ideas about its synthesis. The 7 Li abundance is, on the other hand, a factor of three lower than predicted by standard Big Bang nucleosynthesis theory. Both problems may be explained if decaying suppersymmetric particles affect the synthesis of light elements in the Big Bang. (orig.)

  16. Progress of the Charged Pion Semi-Inclusive Neutrino Charged Current Cross Section in NOvA

    Energy Technology Data Exchange (ETDEWEB)

    Tsaris, Aristeidis [Fermilab

    2017-10-09

    The NOvA experiment is a long-baseline neutrino oscillation experiment designed to measure the rates of electron neutrino appearance and muon neutrino disappearance. The NOvA near detector is located at Fermilab, 800 m from the primary target and provides an excellent platform to measure and study neutrino-nucleus interactions. We present the status of the measurement of the double differential cross section with respect to muon kinematics for interactions involving charged pions in the final state, $\

  17. Primordial nucleosynthesis in the Rh = ct cosmology: pouring cold water on the simmering Universe

    Science.gov (United States)

    Lewis, Geraint F.; Barnes, Luke A.; Kaushik, Rajesh

    2016-07-01

    Primordial nucleosynthesis is rightly hailed as one of the great successes of the standard cosmological model. Here we consider the initial forging of elements in the recently proposed Rh = ct universe, a cosmology that demands linear evolution of the scale factor. Such a universe cools extremely slowly compared to standard cosmologies, considerably depleting the available neutrons during nucleosynthesis; this has significant implications for the resultant primordial abundances of elements, predicting a minuscule quantity of helium which is profoundly at odds with observations. The production of helium can be enhanced in such a `simmering universe' by boosting the baryon to photon ratio, although more than an order of magnitude increase is required to bring the helium mass fraction into accordance with observations. However, in this scenario, the prolonged period of nucleosynthesis results of the efficient cooking of lighter into heavier elements, impacting the resultant abundances of all elements so that, other than hydrogen and helium, there are virtually no light elements present in the universe. Without the addition of substantial new physics in the early universe, it is difficult to see how the Rh = ct universe can be considered a viable cosmological model.

  18. Nova Aquilae 1982: the nature of its dust

    International Nuclear Information System (INIS)

    Longmore, A.J.; Williams, P.M.

    1984-01-01

    Infrared photometric measurements of Nova Aquilae 1982, covering a period from 37 to 261 days after its discovery, have been obtained. Thermal emission was present even from the first observation. The observations show that the conventional picture of dust forming in the nova ejecta does not apply in this case, and suggest that a re-examination of the infrared modelling of earlier novae would be worthwhile. (U.K.)

  19. The UBV Color Evolution of Classical and Symbiotic Novae

    Directory of Open Access Journals (Sweden)

    I. Hachisu

    2015-02-01

    Full Text Available We identified a general course of classical nova outbursts in the B − V vs. U − B diagram. It has been reported that novae show spectra similar to A–F supergiants near optical light maximum. However, they do not follow the supergiant sequence in the color-color diagram, neither the blackbody nor the main-sequence sequence. Instead, we found that novae evolve along a new sequence in the pre-maximum and near-maximum phases, which we call the nova-giant sequence. This sequence is parallel to but Δ(U − B ≈ −0.2 mag bluer than the supergiant sequence. After optical maximum, its color quickly evolves back blueward along the same nova-giant sequence and reaches the point of free-free emission (B − V = −0.03, U − B = −0.97 and stays there for a while, which is coincident with the intersection of the blackbody sequence and the nova-giant sequence. Then the color evolves leftward (blueward in B − V but almost constant in U − B due mainly to development of strong emission lines. This is the general course of nova outbursts in the color-color diagram, which is deduced from eight well-observed novae including various speed classes. For a nova with unknown extinction, we can determine a reliable value of the color excess by matching the observed track of the target nova with this general course. This is a new and convenient method for obtaining color excesses of classical novae. Using this method, we redetermined the color excesses of nineteen well-observed novae.

  20. Assessing site formation and assemblage integrity through stone tool refitting at Gruta da Oliveira (Almonda karst system, Torres Novas, Portugal: A Middle Paleolithic case study.

    Directory of Open Access Journals (Sweden)

    Marianne Deschamps

    Full Text Available We use stone tool refitting to assess palimpsest formation and stratigraphic integrity in the basal units of the Gruta da Oliveira archeo-stratigraphic sequence, layers 15-27, which TL and U-series dating places in late Marine Isotope Stage (MIS 5 or early MIS 4. As in most karst contexts, the formation of this succession involved multiple and complex phenomena, including subsidence, bioturbation, carnivore activity and runoff as agents of potential post-depositional disturbance. During phases of stabilization, such as represented by layers 15, 21 and 22, the excavated area was inhabited and refits corroborate that post-depositional displacement is negligible. Layers 23-25 and 16-19 correspond to subdivisions that slice thick geological units primarily formed of material derived from the cave's entrance via slope dynamics. Refit links are consistent with rapid fill-up of the interstitial spaces found in the Karren-like bedrock (for layers 23-25, or left between large boulders after major roof-collapse events (for layers 16-19. Layers 26 (the "Mousterian Cone" and 27 are a "bottom-of-hourglass" deposit underlying the main sedimentary body; the refits show that this deposit consists of material derived from layers 15-25 that gravitated through fissures open in the sedimentary column above. Layer 20, at the interface between two major stratigraphic ensembles, requires additional analysis. Throughout, we found significant vertical dispersion along the contact between sedimentary fill and cave wall. Given these findings, a preliminary analysis of technological change across the studied sequence organized the lithic assemblages into five ensembles: layer 15; layers 16-19; layer 20; layers 21-22; layers 23-25. The lower ensembles show higher percentages of flint and of the Levallois method. Uniquely at the site, the two upper ensembles feature bifaces and cleavers.

  1. The combined impact of diet, physical activity, sleep and screen time on academic achievement: a prospective study of elementary school students in Nova Scotia, Canada.

    Science.gov (United States)

    Faught, Erin L; Ekwaru, John P; Gleddie, Douglas; Storey, Kate E; Asbridge, Mark; Veugelers, Paul J

    2017-03-09

    Few studies have investigated the independent associations of lifestyle behaviors (diet, physical activity, sleep, and screen time) and body weight status with academic achievement. Even fewer have investigated the combined effect of these behaviors on academic achievement. We hypothesize that the combined effect of these behaviors will have a higher impact on academic achievement than any behavior alone, or that of body weight status. In 2011, 4253 grade 5 (10-11 years old) students and their parents were surveyed about the child's diet, physical activity, screen time and sleep. Students' heights and weights were measured by research assistants. Academic achievement was measured using provincial standardized exams in mathematics, reading and writing, and was expressed as 'meeting' or 'not meeting' expectations as per standardized criterion. Exams were written 1 year following the measurement of lifestyle behaviors. Lifestyle behaviors were measured with self- and parental proxy reports and expressed as meeting recommendations (yes/no) for each behavior. Mixed effects logistic regression models adjusting for demographic confounders and caloric intake were used to determine the independent and combined associations. Meeting dietary recommendations was associated with increased likelihood of meeting academic expectations for each of math, reading and writing. Meeting recommendations for screen time and sleep was associated with meeting expectations for writing. For all three subjects, meeting additional lifestyle behavior recommendations was associated with higher likelihood of meeting expectations. Children who met 7-9 lifestyle behavior recommendations had greater than three-times the odds of meeting expectations for reading compared to those who met 0-3 recommendations (OR: 3.07, 95% CI: 2.09, 4.51), and 1.47 and 2.77 times the odds of meeting expectations in mathematics and writing, respectively. Body weight status was not associated with academic achievement

  2. Accretion onto hot white dwarfs in relation to symbiotic novae

    International Nuclear Information System (INIS)

    Livio, M.; Prialnik, D.; Regev, O.

    1989-01-01

    Numerical calculations are used to study the hydrodynamic evolution of a hot white dwarf with 1 solar mass accreting hydrogen-rich matter at rates between 10 to the -8th and 10 to the -6th solar masses/yr. It is found that for accretion at a rate of about 10 to the -8th solar masses/yr, nova-type outbursts of long duration occur at intervals of about 1500 yr. About half of the accreted envelope is ejected during these outbursts. At a rate of about 10 to the -7th solar masses/yr, the star alternates between comparable periods at a high plateau luminosity and giant dimensions and periods at a low luminosity and white dwarf dimension. At 10 to the -6th solar masses/yr, equilibrium is achieved with a typical red giant luminosity supported by steady hydrogen burning. It is concluded that symbiotic novae are more likely to occur in detached systems involving wind accretors. Thus, the contribution of symbiotic stars to the frequency of type I supernovae is severely constrained. 39 refs

  3. ECONOMIA SOCIAL INCORPORATIVA (e as novas linguagens

    Directory of Open Access Journals (Sweden)

    Welinton dos Santos

    2017-05-01

    Full Text Available A inovação tecnológica aliada à interação de comunicação sem limites, chamada de “Economia Social Incorporativa”, sendo uma rede integrada e sociável as populações do mundo. Baseada em uma pesquisa bibliográfica de caráter qualitativo e documental mostrando que a comunicação, informações e tecnologias evoluem surgindo novos materiais em destaque o grafeno, composto por átomos de carbono com alta condutividade térmica e elétrica, flexível e resistente, material que pode substituir o silício e permitir a segunda revolução tecnológica e levando consigo a economia. Com esses feitos tecnológicos a humanidade tende a estar mais do que nunca com uma ligação inseparável das novas tecnologias que vem aparecendo de forma exponencial no mercado estimulando assim mais do que nunca a economia social. O futuro visa uma nova economia que está em transformação, provocando mudanças significativas na política econômica mundial, e por isso, todos os esforços nesta nova dinâmica de conscientização do comportamento social integrativo auxilia numa política estratégica global mais justa e igualitária.

  4. Nova Scotia Energy Strategy : progress report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-02-01

    Nova Scotia's energy strategy addresses all aspects of energy production and use, from offshore oil and gas to electricity and coal, to climate change and renewable resources. It also encompasses energy conservation and efficiency. This progress report highlights the efforts that the province has made to promote exploration, improve efficiency of regulations and approval processes and promote the oil and natural gas sector. Efforts have also been made to support local businesses, address climate change issues and protect the environment. The strategy demonstrates how new energy resources can be used to build a more prosperous and self-reliant province. The progress report focuses on the following 3 themes: powering the economy; improving the environment; and, securing Nova Scotia's future. The report emphasizes that the growing oil and gas industry brings many opportunities for new jobs and a stronger economy. In the next 12 to 18 months, about 8 to 10 offshore exploration wells will be drilled, which is more than in the last decade. Funding will be provided to extend pipeline systems beyond franchise areas approved by the Nova Scotia Utility and Review Board. In May 2002, the Electricity Marketplace Governance Committee was formed to make recommendations on how competition can be introduced into the province's electricity market. The Department of Energy has been working to implement initiatives to increase the use of renewable energy sources such as solar and wind power. In October 2002, new wind turbines began producing electricity in 3 communities on Cape Breton Island. A key priority is to respond to climate change and reduce greenhouse gas emissions as well as emissions of mercury, sulphur, nitrogen, and ozone. The energy strategy also identifies the need to provide competitive taxation regimes.

  5. Discovery of a Probable Nova in M81 and Photometry of Three M81 Novae

    Science.gov (United States)

    Hornoch, K.; Errmann, R.; Carlisle, Ch.; Vaduvescu, O.

    2015-02-01

    We report the discovery of a probable nova in M81 on a co-added 1600-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~1.6" seeing on 2015 Jan.

  6. Multicolour photometry and spectroscopy of the slow nova V475 Sct (Nova Scuti 2003)

    Czech Academy of Sciences Publication Activity Database

    Chochol, D.; Katysheva, N.A.; Pribulla, T.; Schmidtobreick, L.; Shugarov, S.Yu.; Škoda, Petr; Šlechta, Miroslav; Vittone, A.A.; Volkov, I. M.

    2006-01-01

    Roč. 6, č. 1 (2006), s. 137-142 ISSN 1009-9271 Institutional research plan: CEZ:AV0Z10030501 Keywords : cataclysmic variables * circumstellar matter * stars: novae Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.746, year: 2006

  7. Photometric and spectroscopic variability of the slow nova V475 Sct (Nova Scuti 2003)

    Czech Academy of Sciences Publication Activity Database

    Chochol, D.; Katysheva, N.A.; Pribulla, T.; Schmidtobreick, L.; Shugarov, S.Yu.; Škoda, Petr; Šlechta, Miroslav; Vittone, A.A.; Volkov, I. M.

    2005-01-01

    Roč. 35, č. 2 (2005), s. 107-129 ISSN 1335-1842 R&D Projects: GA AV ČR KSK2043105 Institutional research plan: CEZ:AV0Z1003909 Keywords : novae * photometry * spectroscopy Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  8. Discovery of a New Classical Nova Shell Around a Nova-like Cataclysmic Variable

    Science.gov (United States)

    Guerrero, Martín A.; Sabin, Laurence; Tovmassian, Gagik; Santamaría, Edgar; Michel, Raul; Ramos-Larios, Gerardo; Alarie, Alexandre; Morisset, Christophe; Bermúdez Bustamante, Luis C.; González, Chantal P.; Wright, Nick J.

    2018-04-01

    The morphology and optical spectrum of IPHASX J210204.7+471015, a nebula classified as a possible planetary nebula are, however, strikingly similar to those of AT Cnc, a classical nova shell around a dwarf nova. To investigate its true nature, we have obtained high-resolution narrowband [O III] and [N II] images and deep optical spectra. The nebula shows an arc of [N II]-bright knots notably enriched in nitrogen, while an [O III]-bright bow shock is progressing throughout the ISM. Diagnostic line ratios indicate that shocks are associated with the arc and bow shock. The central star of this nebula has been identified by its photometric variability. Time-resolved photometric and spectroscopic data of this source reveal a period of 4.26 hr, which is attributed to a binary system. The optical spectrum is notably similar to that of RW Sex, a cataclysmic variable star (CV) of the UX UMa nova-like (NL) type. Based on these results, we propose that IPHASX J210204.7 + 471015 is a classical nova shell observed around a CV-NL system in quiescence.

  9. DAQ Software Contributions, Absolute Scale Energy Calibration and Background Evaluation for the NOvA Experiment at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Flumerfelt, Eric Lewis [Univ. of Tennessee, Knoxville, TN (United States)

    2015-08-01

    The NOvA (NuMI Off-axis ve [nu_e] Appearance) Experiment is a long-baseline accelerator neutrino experiment currently in its second year of operations. NOvA uses the Neutrinos from the Main Injector (NuMI) beam at Fermilab, and there are two main off-axis detectors: a Near Detector at Fermilab and a Far Detector 810 km away at Ash River, MN. The work reported herein is in support of the NOvA Experiment, through contributions to the development of data acquisition software, providing an accurate, absolute-scale energy calibration for electromagnetic showers in NOvA detector elements, crucial to the primary electron neutrino search, and through an initial evaluation of the cosmic background rate in the NOvA Far Detector, which is situated on the surface without significant overburden. Additional support work for the NOvA Experiment is also detailed, including DAQ Server Administration duties and a study of NOvA’s sensitivity to neutrino oscillations into a “sterile” state.

  10. 10% discount at Novae restaurants for students

    CERN Document Server

    2016-01-01

    A 10% discount will be granted for students dining in restaurants 1 and 2 (on the Meyrin site) during the summer from 15 June 2016 to 15 September 2016.   A special badge will be issued by the respective secretariats if the student fulfils the following criteria:  Is under 25 years old; Is in possession of a student card issued by a University or college; Has a CERN contract > 1 month (Users, Summer Students, Trainees, etc). This badge and the CERN access card will have to be shown at the Novae restaurants in order to benefit from this discount.

  11. Dwarf novae in outburst: modelling the observations

    International Nuclear Information System (INIS)

    Pringle, J.E.; Verbunt, F.

    1986-01-01

    Time-dependent accretion-disc models are constructed and used to calculate theoretical spectra in order to try to fit the ultraviolet and optical observations of outbursts of the two dwarf novae VW Hydri and CN Orionis. It is found that the behaviour on the rise to outburst is the strongest discriminator between theoretical models. The mass-transfer burst model is able to fit the spectral behaviour for both objects. The disc-instability model is unable to fit the rise to outburst in VW Hydri, and gives a poor fit to the observations of CN Orionis. (author)

  12. NOVA integrated alignment/diagnostic sensors

    International Nuclear Information System (INIS)

    1978-01-01

    Under Contract 3772003 to the Lawrence Livermore Laboratory, Aerojet ElectroSystems Company has investigated a number of alignment system design topics for the NOVA and SHIVA upgrade lasers. Prior reports dealt with the Main Beam Alignment System, and with Multipass Amplifier Alignment Concepts. This report, which completes the contract, examines ways in which the Return Beam Diagnostic (RBD) package and Incident Beam Diagnostic (IBD) packages may be reconfigured to a more integrated package. In particular, the report shows that the RBD optics may be directly integrated in the Pointing Focus and Centering (PFC) sensor, and that the IBD optics may use the same basic common configuration as the PFC/RBD package

  13. Nova isolates noise to quieten stations

    International Nuclear Information System (INIS)

    Milner, G.J.; Frank, L.D.

    1993-01-01

    This paper reviews a technique developed by Nova Corp., to help isolate and measure the acoustic power of individual components in a pipeline compressor and pumping station. The procedure calculates the sound pressure levels of each piece of equipment independently. Based on these measurements, a prediction can be made of the effect of various types of noise treatment techniques on the overall sound levels currently generated or proposed in a future project. This paper describes the equipment to measure the sound levels, techniques for actually measuring the compressor station or equipment area, and techniques used to generate a remediation plan

  14. The first results from the NOVA experiment

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    The NOvA experiment measures neutrino oscillation phenomena over a baseline of 810 km using a narrow-band muon neutrino beam that has a peak energy near 2 GeV. With this configuration the experiment has sensitivity to the oscillation parameters that are the least known. Installation of the detector began almost 2 years ago and the collaboration has been recording data since then. The collaboration released its first measurements of neutrino oscillation phenomena this summer. The results of those measurements and the future prospects of the experiment will be discussed.

  15. Chemical abundances associated with gamma-ray bursts: nucleosynthesis in afterglows

    Science.gov (United States)

    Hu, Tao; Wang, Min

    2014-03-01

    Gamma-ray burst (GRB) ejecta carries huge amounts of energy expanding into the surrounding medium and heats up these materials, making it possible that nucleosynthesis can take place in such hot sites in afterglow stage. Here, we study possible changes in chemical abundances in the GRB afterglow processes of Wolf-Rayet (WR) star wind environments (Case A) and constant density surroundings (Case B). We find that the light element of lithium-beryllium-boron could occur in the afterglows via He+He process and spallation reactions. Some isotopes of F, Ne, Mg, Al, Si, P, S and Fe-group elements are also new species formed in the afterglows via proton-, neutron- and α-capture. The results show that the nucleosynthetic yields might be a diagnostic of the GRB's ambient environment. Our calculations indicate that Mg, Al, Si, P, Cr, Mn, Fe and Co have trended to appear in Case A, while Ne, Ti and Ni trend to occur in Case B. Furthermore, although some species have occurred both in Cases A and B, their mass fractions are quite different in these two cases. Here, we show that the mass fractions of 7Li, 7Be, 24Mg and 30Si are higher in Case A than that in Case B, but 18F gives an opposite conclusion. Nucleosynthetic outputs might also be an indice to estimate the luminosity-temperature relation factor β. In this study, when β reduces, the mass abundances of 11B and 20Ne are higher in Case B than that in Case A; in contrast, as the β becomes larger, this trend would be reversed; therefore, perhaps we could select the above elements as the indicators to estimate the properties of the surroundings around the GRBs. We also suggest that the spectroscopic observations of a GRB afterglow could only reveal the nucleosynthetic outputs from the interaction site between the GRB jet and its ambient matter, but could not represent the original composition of the pre-GRB surrounding medium.

  16. First inventory of the echinoderms from Juan de Nova (Iles Eparses ...

    African Journals Online (AJOL)

    Juan de Nova is one of the Iles Eparses, French islands scattered in the Mozambique Channel (Western India Ocean). They have been kept isolated of the anthropogenic influences which makes them rare areas to study biodiversity and provides elements of comparison with areas that are strongly impacted by urbanization ...

  17. Astrophysical S-factor of the 32He(α,γ) 733 7Be reaction in the Big-Bang nucleosynthesis

    Science.gov (United States)

    Ghamary, Motahareh; Sadeghi, Hossein; Mohammadi, Saeed

    2018-05-01

    In the present work, we have studied the properties of the 23He(α , γ) 47Be reaction. The direct radiative capture nuclear reactions in the Big-Bang nucleosynthesis mainly, are done in the external areas of inter-nuclear interaction range and play an essential role in nuclear astrophysics. Among of these reactions, the 23He(α , γ) 47Be reaction with Q = 1.586 MeV is the main part of the Big-Bang nucleosynthesis chain reactions. This reaction can be used to understand the physical and chemical properties of the sun as well as can be justified the lake of the observed solar neutrino in the detector of the Earth. Since product neutrino fluxes are predicated in the center of the sun by the decay of 7Be and 8B, and almost are proportional to the astrophysical S-factor for the 23He(α , γ) 47Be reaction, S34. The 23He(α , γ) 47Be reaction is considered the key to solve the solar neutrino puzzle. Finally, we have astrophysical S-factor obtained for the ground S1,3/2-, first excited S1,1/2-and total S34 states by modern nucleon-nucleon two-body local potential models. We have also compared the obtained S-factor with experimental data and other theoretical works.

  18. Experimental challenge to the big-bang nucleosynthesis - Cosmological 7Li problem in BBN

    Science.gov (United States)

    Kubono, S.; Kawabata, T.; Hou, S. Q.; He, J. J.

    2018-04-01

    The primordial nucleosynthesis(BBN) right after the big bang (BB) is one of the key elements that basically support the BB model. The BBN is well known that it produced primarily light elements, and explains reasonably most of the elemental abundances. However, there remains an interesting and serious question. That is so called the cosmological 7Li problem in BBN. The BBN simulations using nuclear data together with the recent detailed micro-wave background measurements explain most of the light elements including D, 4He, etc, but the 7Li abundance is over predicted roughly by a factor of three. Although this problem should be investigated in all the fields relevant including physics and astronomical observations, I will concentrate my discussion on the nuclear physics side, especially the recent progress for studying the last possible major destruction process of 7Be, the 7Be(n,α)4He reaction, which would reduce the overproduction if the cross section is large. There are several efforts recently made for the 7Be(n,α)4He reaction in the world. A new theoretical estimate was made compiling all available data of the mirror reaction 7Li(p,α)4He, suggesting about one order smaller reaction rate than the ones currently being used (Wagoner rate). The n-TOF group measured some part of the s-wave components of the reaction, suggesting that the s-wave contributions are much smaller than the Wagoner rate. The p-wave component was measured clearly at RCNP, Osaka using the time-reverse reaction 4He(α,n)7Be, indicating that the p-wave contribution dominates at the effective temperature region for the BBN. However, the sum of the s-wave and p-wave contributions is about one order of magnitude smaller than the Wagoner rate. It should be of great interest to confirm by the indirect method, Trojan-Horse method to deduce cross sections at the effective temperature region, and also see the cross sections for a wider energy range systematically, which is under way by the BELICOS

  19. ON THE SPECTROSCOPIC CLASSES OF NOVAE IN M33

    International Nuclear Information System (INIS)

    Shafter, A. W.; Darnley, M. J.; Bode, M. F.; Ciardullo, R.

    2012-01-01

    We report the initial results from an ongoing multi-year spectroscopic survey of novae in M33. The survey resulted in the spectroscopic classification of six novae (M33N 2006-09a, 2007-09a, 2009-01a, 2010-10a, 2010-11a, and 2011-12a) and a determination of rates of decline (t 2 times) for four of them (2006-09a, 2007-09a, 2009-01a, and 2010-10a). When these data are combined with existing spectroscopic data for two additional M33 novae (2003-09a and 2008-02a), we find that five of the eight novae with available spectroscopic class appear to be members of either the He/N or Fe IIb (hybrid) classes, with only two clear members of the Fe II spectroscopic class. This initial finding is very different from what would be expected based on the results for M31 and the Galaxy where Fe II novae dominate, and the He/N and Fe IIb classes together make up only ∼20% of the total. It is plausible that the increased fraction of He/N and Fe IIb novae observed in M33 thus far may be the result of the younger stellar population that dominates this galaxy, which is expected to produce novae that harbor generally more massive white dwarfs than those typically associated with novae in M31 or the Milky Way.

  20. Results of Statewide TerraNova Testing, Fall 1998.

    Science.gov (United States)

    La Marca, Paul M.

    This summary provides key findings about state, district, and school level performance on the TerraNova examinations (CTB/McGraw Hill) in Nevada in 1998-1999. The TerraNova tests are used to assess students in grades 4, 8, and 10 as stipulated by Nevada law. Within this summary, a description of performance as measured by national percentile…

  1. The progenitor of Nova Cygni 2006 (=V2362 Cyg)

    NARCIS (Netherlands)

    Steeghs, D.; Greimel, R.; Drew, J.; Irwin, M.; Gaensicke, B.; Groot, P.J.; Knigge, C.

    2006-01-01

    We report on the detection of the likely progenitor to Nova Cygni 2006 = V2362 Cyg (IAUC #8697, #8698, ATel #792) using images from the INT Photometric H-Alpha Survey (IPHAS; http://www.iphas.org). The field containing the classical nova was observed as part of our galactic plane survey on Aug. 3rd

  2. NOVA: a software to analyze complexome profiling data

    NARCIS (Netherlands)

    Giese, H.; Ackermann, J.; Heide, H.; Bleier, L.; Drose, S.; Wittig, I.; Brandt, U.; Koch, I.

    2015-01-01

    SUMMARY: We introduce nova, a software for the analysis of complexome profiling data. nova supports the investigation of the composition of complexes, cluster analysis of the experimental data, visual inspection and comparison of experiments and many other features. AVAILABILITY AND IMPLEMENTATION:

  3. Characterisation and application of NovaFiber lignin

    NARCIS (Netherlands)

    Gosselink, R.J.A.; Snijder, M.H.B.; Kranenbarg, A.; Keijsers, E.R.P.; Jong, de E.; Stigsson, L.L.

    2004-01-01

    Sulphur-free lignin coming from a novel alkaline-pulping process called NovaFiber, which has been developed by KIRAM AB, has been characterised and evaluated for potential applications. A Kraft lignin has been used for comparison. Considering the characterisation results of a NovaFiber softwood and

  4. A Recurrent Nova Super-Remnant in the Andromeda Galaxy

    DEFF Research Database (Denmark)

    Darnley, M. J.; Hounsell, R.; O'Brien, T. J.

    2017-01-01

    Here we report that the most rapidly recurring nova, M31N 2008-12a, which erupts annually, is surrounded by a "nova super-remnant" which demonstrates that M31N 2008-12a has erupted with high frequency for millions of years....

  5. Optical components for the Nova laser

    International Nuclear Information System (INIS)

    Wallerstein, E.P.; Baker, P.C.; Brown, N.J.

    1982-01-01

    In addition to its other characteristics, the Nova Laser Fusion facility may well be the largest precision optical project ever undertaken. Moreover, during the course of construction, concurrent research and development has been successfully conducted, and has resulted in significant advances in various technical areas, including manufacturing efficiency. Although assembly of the first two beams of Nova is just commencing, the optical production, including construction of the special facilities required for many of the components, has been underway for over three years, and many phases of the optical manufacturing program for the first 10 beams will be completed within the next two years. On the other hand, new requirements for second and third harmonic generation have created the need to initiate new research and development. This work has been accomplished through the enormous cooperation DOE/LLNL has received from commercial industry on this project. In many cases, industry, where much of the optical component research and development and virtually all of the manufacturing is being done, has made substantial investment of its own funds in facilities, equipment, and research and development, in addition to those supplied by DOE/LLNL

  6. Hydrodynamic instability experiments on the Nova laser

    International Nuclear Information System (INIS)

    Remington, B.A.; Glendinning, S.G.; Kalantar, D.H.

    1996-08-01

    Hydrodynamic instabilities in compressible plasmas play a critical role in the fields of inertial confinement fusion (ICF), astrophysics, and high energy-density physics. We are, investigating hydrodynamic instabilities such as the Rayleigh-Taylor (RT) instability, at high compression at the Nova laser in a series of experiments, both in planar and in spherical geometry. In the indirect drive approach, a thermal x-ray drive is generated by focusing the Nova laser beams into a Au cylindrical radiation cavity (hohlraum). Issues in the instability evolution that we are examining are shock propagation and foil compression, RT growth of 2D versus 3D single-mode perturbations, drive pulse shape, perturbation location at the ablation front versus at an embedded interface, and multimode perturbation growth and nonlinear saturation. The effects of convergence on RT growth are being investigated both with hemispherical implosions of packages mounted on the hohlraum wall and with spherical implosions of capsules at the center of the hohlraum. Single-mode perturbations are pre-imposed at the ablation front of these capsules as a seed for the RT growth. In our direct drive experiments, we are investigating the effect of laser imprinting and subsequent RT growth on planar foils, both at λ Laser = 1/3 μm and 1/2 μm. An overview is given describing recent progress in each of these areas

  7. The SSS classical nova V5116 Sgr

    Science.gov (United States)

    Sala, G.; Ness, J.; Greiner, J.; Hernanz, M.

    2017-10-01

    XMM-Newton observed the nova V5116 Sgr during its supersoft phase (SSS). V5116 Sgr showed a decrease of the flux by a factor around 8 during 2/3 of the orbital period. The broad band EPIC spectra remain unchanged during the different flux phases, suggesting an occultation of the central source in a high inclination system. While the global SED does not change significantly, the RGS spectrum is changing between the high and the low flux phases. The non-occultation phase shows a typical white dwarf atmosphere spectrum, dominated by absorption lines. During the low flux periods an extra component of emission lines is superimposed to the soft X-ray continuum. This supports the picture of V5116 Sgr as the clearest example of a system switching between the SSa class of SSS novae, with spectra dominated by absorption lines, and the SSe class, showing an emission lines component. In addition, the simultaneous OM images allow us to find a phase solution for the X-ray light-curve. A thick rim of the accretion disk as the one developed for the SSSs CAL 87, RX J0019.8, and RX J0513.9 could provide a plausible model both for the optical and the X-ray light curve of V5116 Sgr.

  8. Legislating Interprofessional Regulatory Collaboration in Nova Scotia

    Directory of Open Access Journals (Sweden)

    William Lahey

    2013-10-01

    Full Text Available To shift health professions regulation from traditional to ‘collaborative’ self-regulation, Nova Scotia has adopted legislation which will: make all self-regulating health professions members of the Regulated Health Professions Network; mandate the Network to facilitate voluntary collaboration among its members; and enable regulators to work together on investigations of patient complaints, to adjust scopes of practice on an ongoing basis and to adjudicate appeals of unsuccessful applicants for registration. The goals are to give health professions regulation the capacity to enable and support the functioning of interprofessional teams. The legislation was adopted primarily for two reasons: collaborative development and unanimous support by all of the province’s self-regulating professions; and alignment with the government’s health care reform agenda and its emphasis on collaborative team-based care. Contrary to the approach of several other provinces, the legislation will enable but not require regulators to collaborate on the premise that consensual collaboration is more likely to happen, to be meaningful and to yield tangible benefits. Support for this approach can be taken from the impressive collaborative work on which the legislation is based. Evaluation will be critical, and the five-year review required by the legislation will give Nova Scotia the opportunity to test not only the legislation but the ideas on which it is based. The extent of the legislation’s reliance on voluntary process will prove to be either its greatest strength or its greatest weakness.

  9. Evaluation of petroleum products pricing regulation in Nova Scotia : a 2 year review

    International Nuclear Information System (INIS)

    2008-11-01

    Gasoline price regulation was introduced in Nova Scotia on July 1st, 2006. This report presented the findings and recommendations of a review of the first two years of the gasoline price regulation in Nova Scotia. The regulations had three main objectives. This review examined whether, and to what extent, they were achieved. The objectives were to stabilize price, maintain industry infrastructure, and minimize cost to consumers. The report described the rationale for the regulation, study objectives, and approach taken to gasoline regulation in Nova Scotia, including the objectives and technical aspects of how regulation works. The gasoline market in Nova Scotia was examined, including the market structure and competitive behaviour in an unregulated market. The report also provided some theoretical perspectives on how regulation was likely to affect industry structure and competitive behaviour. The extent to which the regulation was meeting its objectives was then assessed and perspectives on the regulation from consumers, retailers and wholesalers were offered. Last, the report provided a review of the findings in terms of the key elements of regulatory design and set out recommendations for improving the system. It was recommended that in order to improve certainty, particularly given the regulated price differences amongst grades, the regulations should be amended to include grade specifications referencing octane ratings. tabs., figs

  10. The Shape of Long Outbursts in U Gem Type Dwarf Novae from AAVSO Data

    Science.gov (United States)

    Cannizzo, John K.

    2012-01-01

    We search the American Association of Variable Star Observers (AAVSO) archives of the two best studied dwarf novae in an attempt to find light curves for long out bursts that are extremely well-characterized. The systems are U Gem and S8 Cyg. Our goal is to search for embedded precursors such as those that have been found recently in the high fidelity Kepler data for superoutbursts of some members of the 8U UMa subclass of dwarf novae. For the vast majority of AAV80 data, the combination of low data cadence and large errors associated with individual measurements precludes one from making any strong statement about the shape of the long outbursts. However, for a small number of outbursts, extensive long term monitoring with digital photometry yields high fidelity light curves. We report the finding of embedded precursors in two of three candidate long outbursts. This reinforces van Paradijs' finding that long outbursts in dwarf novae above the period gap and superoutbursts in systems below the period gap constitute a unified class. The thermal-tidal instability to account for superoutbursts in the SU UMa stars predicts embedded precursors only for short orbital period dwarf novae, therefore the presence of embedded precursors in long orbital period systems - U Gem and SS Cyg - argues for a more general mechanism to explain long outbursts.

  11. The Role of Fe and Ni for S-process Nucleosynthesis and Innovative Nuclear Technologies

    CERN Document Server

    Giubrone, G; Perkowski, J; Andriamonje, S; Carrapico, C; Wallner, A; Vannini, G; Quesada, J M; Lederer, C; Tarrio, D; Berthier, B; Lozano, M; Krticka, M; Domingo-Pardo, C; Chiaveri, E; Jericha, E; Ferrari, A; Massimi, C; Avrigeanu, V; Martinez, T; Guerrero, C; Andrzejewski, J; Karadimos, D; Mendoza, E; Ganesan, S; Vlachoudis, V; Milazzo, P M; Cortes, G; Becares, V; Tain, J L; Variale, V; Quinones, J; Calvino, F; Kappeler, F; Gunsing, F; Gramegna, F; Colonna, N; Marrone, S; Lebbos, E; Paradela, C; Mastinu, P F; Vaz, P; Tassan-Got, L; Kadi, Y; Dillman, I; Cano-Ott, D; Brugger, M; Audouin, L; Fernandez-Ordonez, M; Sarmento, R; Becvar, F; Goncalves, I F; Martin-Fuertes, F; Cerutti, F; Pina, G; Mosconi, M; Tagliente, G; Duran, I; Berthoumieux, E; Praena, J; Ioannides, K; Weiss, C; Mirea, M; Gomez-Hornillos, M B; Vlastou, R; Calviani, M; Nolte, R; Mengoni, A; Gonzalez-Romero, E; Marganiec, J; Leeb, H; Heil, M; Meaze, M H; Pavlik, A; Belloni, F; Harrispopulos S

    2011-01-01

    The accurate measurement of neutron capture cross sections of all Fe and Ni isotopes is important for disentangling the contribution of the s-process and the r-process to the stellar nucleosynthesis of elements in the mass range 60 < A < 120. At the same time, Fe and Ni are important components of structural materials and improved neutron cross section data is relevant in the design of new nuclear systems. With the aim of obtaining improved capture data on all stable iron and nickel isotopes, a program of measurements has been launched at the CERN Neutron Time of Flight Facility n_TOF.

  12. Astrophysical S-factor for destructive reactions of lithium-7 in big bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Komatsubara, Tetsuro; Kwon, YoungKwan; Moon, JunYoung; Kim, Yong-Kyun [Rare Isotope Science Project, Institute for Basic Science, Daejeon (Korea, Republic of); Moon, Chang-Bum [Hoseo University, Asan, Chungnam (Korea, Republic of); Ozawa, Akira; Sasa, Kimikazu; Onishi, Takahiro; Yuasa, Toshiaki; Okada, Shunsuke; Saito, Yuta [Division of Physics, University of Tsukuba, Tsukuba, Ibaraki (Japan); Hayakawa, Takehito; Shizuma, Toshiyuki [Japan Atomic Energy Agency, Shirakata Shirane, Tokai, Ibaraki (Japan); Kubono, Shigeru [RIKEN, Hirosawa, Wako, Saitama (Japan); Kusakabe, Motohiko [School of Liberal Arts and Science, Korea Aerospace University (Korea, Republic of); Kajino, Toshitaka [National Astronomical Observatory, Osawa, Mitaka, Tokyo (Japan)

    2014-05-02

    One of the most prominent success with the Big Bang models is the precise reproduction of mass abundance ratio for {sup 4}He. In spite of the success, abundances of lithium isotopes are still inconsistent between observations and their calculated results, which is known as lithium abundance problem. Since the calculations were based on the experimental reaction data together with theoretical estimations, more precise experimental measurements may improve the knowledge of the Big Bang nucleosynthesis. As one of the destruction process of lithium-7, we have performed measurements for the reaction cross sections of the {sup 7}L({sup 3}He,p){sup 9}Be reaction.

  13. Electron-capture Rates for pf-shell Nuclei in Stellar Environments and Nucleosynthesis

    Science.gov (United States)

    Suzuki, Toshio; Honma, Michio; Mori, Kanji; Famiano, Michael A.; Kajino, Toshitaka; Hidakai, Jun; Otsuka, Takaharu

    Gamow-Teller strengths in pf-shell nuclei obtained by a new shell-model Hamltonian, GXPF1J, are used to evaluate electron-capture rates in pf-shell nuclei at stellar environments. The nuclear weak rates with GXPF1J, which are generally smaller than previous evaluations for proton-rich nuclei, are applied to nucleosynthesis in type Ia supernova explosions. The updated rates are found to lead to less production of neutron-rich nuclei such as 58Ni and 54Cr, thus toward a solution of the problem of over-production of neutron-rich isotopes of iron-group nuclei compared to the solar abundance.

  14. Nucleosynthesis in neutrino-driven, aspherical supernova explosion of a massive star

    International Nuclear Information System (INIS)

    Fujimoto, S.; Hashimoto, M.; Ono, M.; Kotake, K.; Ohnishi, N.

    2011-01-01

    We examine explosive nucleosynthesis of p-nuclei during a delayed neutrino-driven, aspherical supernova explosion aided by standing accretion shock instability, based on two-dimensional hydrodynamic simulations of the explosion of a 15M · star. We find that p-nuclei are mainly produced through γ-processes, and that the nuclei lighter than 92 Mo are abundantly synthesized in slightly neutron-rich bubbles with electron fractions of Y e ≤0.48. 94 Mo, 96 Ru, and 98 Ru, are underproduced compared with the solar system, as in the spherical model.

  15. Multiwavelength monitoring of the dwarf nova VW Hydri

    International Nuclear Information System (INIS)

    Woerd, H. van der; Heise, J.

    1987-01-01

    This paper presents the X-ray observations made as part of the multiwavelength study of the dwarf nova VW Hyi. The X-ray monitoring covered 2 months in 1984. Three normal outbursts, a superoutburst and the quiescent intervals between those outbursts were observed. During quiescence the X-ray flux decreases by a factor of 1.2 to 1.6, which implies that the accretion rate on to the white dwarf decreases by approximately the same factor. The observations during quiescence are consistent with emission from an optically thin, hot (T approx.= 10 8 K) corona. During outburst the X-ray flux increases by two orders of magnitude. The spectrum is characterized as extremely soft, with dominant emission at wavelength above 170 A. (author)

  16. Multiwavelength monitoring of the dwarf nova VW Hydri

    International Nuclear Information System (INIS)

    Amerongen, S. van; Damen, E.; Groot, M.; Kraakman, H.; Parakijs, J. van

    1987-01-01

    Results are presented of five-colour photometric observations (Walraven system) of VW Hyi, made between 1984 July and November, as part of a long-term multiwavelength study of this dwarf nova. The average orbital light and colour curves during quiescence are accurately defined. Apart from a slow decay following outburst during the first quarter of a quiescent interval, neither the average brightness nor the maximum and minimum brightness show a significant secular trend between outbursts. The 3σ upper limits to a secular change in average brightness during the last three-quarters of a quiescent interval range between 0.16 and 0.20 mag in the five passbands. (author)

  17. Event Reconstruction Techniques in NOvA

    Science.gov (United States)

    Baird, M.; Bian, J.; Messier, M.; Niner, E.; Rocco, D.; Sachdev, K.

    2015-12-01

    The NOvA experiment is a long-baseline neutrino oscillation experiment utilizing the NuMI beam generated at Fermilab. The experiment will measure the oscillations within a muon neutrino beam in a 300 ton Near Detector located underground at Fermilab and a functionally-identical 14 kiloton Far Detector placed 810 km away. The detectors are liquid scintillator tracking calorimeters with a fine-grained cellular structure that provides a wealth of information for separating the different particle track and shower topologies. Each detector has its own challenges with the Near Detector seeing multiple overlapping neutrino interactions in each event and the Far Detector having a large background of cosmic rays due to being located on the surface. A series of pattern recognition techniques have been developed to go from event records, to spatially and temporally separating individual interactions, to vertexing and tracking, and particle identification. This combination of methods to achieve the full event reconstruction will be discussed.

  18. New neutrino oscillation results from NOVA

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    Neutrinos oscillate among flavors as they travel because a neutrino of a particular flavor is also a superposition of multiple neutrinos with slightly different masses.  The interferometric nature of oscillations allows these tiny mass differences to be measured, along with the parameters of the PMNS matrix which governs the mixing. However, since neutrinos only interact weakly, a powerful neutrino source and massive detectors are required to measure them. In this talk I will show recently updated results from NOvA, a long-baseline neutrino oscillation experiment at Fermilab with two functionally identical scintillator detectors. I will present measurements of muon neutrino disappearance and electron neutrino appearance, and what constraints those measurements put on the remaining open questions in neutrino oscillations: Is the neutrino mass hierarchy "normal" or "inverted?" Do neutrino oscillations violate CP symmetry? Is the mixing in the atmospheric sector maximal? The recent update includes 50%...

  19. Urban Design - Architectural Workshop Nova Gorica

    Directory of Open Access Journals (Sweden)

    Anja Planišček

    2012-01-01

    Full Text Available The workshop ran through the 2008-09 academic year. The main themes were a thorough design of Magistrala, the main city street, and research of the spatial and programmatic development alongside it. The research was based on the original urban plan of Nova Gorica designed by architect Edvard Ravnikar in 1949.The workshop was divided into two phases. In the first phase, students researched the possibilities of an overall design for Magistrala (traffic arrangement, relations between built and vacant space, green spaces, public and private domain etc.. In the second phase, they proposed urban architectural interventions in the open spaces along Magistrala (university campus in the northern part of the city, student housing, residential areas, main square, law court, hotel etc..

  20. Nova abordagem no tratamento da esquizofrenia

    Directory of Open Access Journals (Sweden)

    Walter Speltri

    1966-12-01

    Full Text Available Foram tratados 11 casos de esquizofrenia com a guanetidina, substância considerada, do ponto de vista farmacodinâmico, como simpaticoplégica. Na opinião do autor, os surpreendentes e significativos resultados obtidos autorizam uma nova abordagem nas pesquisas à procura da etiopatogenia da esquizofrenia e, a partir dos elementos colhidos, considera plausível uma "teoria psicossomática da esquizofrenia". Recusa-se, entretanto, a cair no atraente, mas inútil, terreno especulativo. Prefere aguardar que os farmacologistas e fisiologistas forneçam dados pais precisos sobre o mecanismo de ação da guanetidina e que novos estudos confirmem seus resultados para, depois, dar publicidade à sua teoria.

  1. Heavy element abundances of Nova Cygni 1975

    International Nuclear Information System (INIS)

    Ferland, G.J.; Shields, G.A.

    1978-01-01

    McDonald observations of the nebular phase of the outburst of Nova Cygni 1975 are analyzed to measure the abundances of several heavy elements. A new analytical procedure is used to derive the electron density and temperature from the emission line intensities of [O III], [Ne III], and He I observed between days 40 and 120. These physical conditions are used to derive the abundances. We find that Fe has approximately a solar abundance, whereas C, N, O, and Ne are enhanced by factors approx.20 to 100. The enhanced abundance of neon was theoretically unexpected.The derived physical conditions and line intensities are compared with predictions of an equilibrium photoionization model. The model successfully predicts the intensities of He I, [O III], and [Ne III]; but it underestimates the strength of [Ne V] and [Fe VII], which may originate in a mechanically heated ''subcoronal'' line region

  2. ORIGINS OF ABSORPTION SYSTEMS OF CLASSICAL NOVA V2659 CYG (NOVA CYG 2014)

    Energy Technology Data Exchange (ETDEWEB)

    Arai, A.; Kawakita, H. [Koyama Astronomical Observatory, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan); Shinnaka, Y. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Tajitsu, A., E-mail: arai6a@cc.kyoto-su.ac.jp [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A’ohoku Place, Hilo, Hawaii 96720 (United States)

    2016-10-10

    We report on high-dispersion spectroscopy results of a classical nova V2659 Cyg (Nova Cyg 2014) that are taken 33.05 days after the V -band maximum. The spectrum shows two distinct blueshifted absorption systems originating from H i, Fe ii, Ca ii, etc. The radial velocities of the absorption systems are −620 km s{sup −1}, and −1100 to −1500 km s{sup −1}. The higher velocity component corresponds to the P-Cygni absorption features frequently observed in low-resolution spectra. Much larger numbers of absorption lines are identified at the lower velocity. These mainly originate from neutral or singly ionized Fe-peak elements (Fe i, Ti ii, Cr ii, etc.). Based on the results of our spectroscopic observations, we discuss the structure of the ejecta of V2659 Cyg. We conclude that the low- and high-velocity components are likely to be produced by the outflow wind and the ballistic nova ejecta, respectively.

  3. Lorentz invariance violation in the neutrino sector: a joint analysis from big bang nucleosynthesis and the cosmic microwave background

    Science.gov (United States)

    Dai, Wei-Ming; Guo, Zong-Kuan; Cai, Rong-Gen; Zhang, Yuan-Zhong

    2017-06-01

    We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The effect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which influences the power spectrum of the cosmic microwave background at the recombination epoch. In combination with the latest measurement of the primordial helium-4 abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density.

  4. Lorentz invariance violation in the neutrino sector: a joint analysis from big bang nucleosynthesis and the cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Wei-Ming; Cai, Rong-Gen [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Guo, Zong-Kuan [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China); University of Chinese Academy of Sciences, School of Astronomy and Space Science, Beijing (China); Zhang, Yuan-Zhong [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China)

    2017-06-15

    We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The effect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which influences the power spectrum of the cosmic microwave background at the recombination epoch. In combination with the latest measurement of the primordial helium-4 abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density. (orig.)

  5. Lorentz invariance violation in the neutrino sector: a joint analysis from big bang nucleosynthesis and the cosmic microwave background

    International Nuclear Information System (INIS)

    Dai, Wei-Ming; Cai, Rong-Gen; Guo, Zong-Kuan; Zhang, Yuan-Zhong

    2017-01-01

    We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The effect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which influences the power spectrum of the cosmic microwave background at the recombination epoch. In combination with the latest measurement of the primordial helium-4 abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density. (orig.)

  6. THE UNUSUALLY LUMINOUS EXTRAGALACTIC NOVA SN 2010U

    International Nuclear Information System (INIS)

    Czekala, Ian; Berger, E.; Chornock, R.; Marion, G. H.; Margutti, R.; Challis, P.; Pastorello, A.; Botticella, M. T.; Ergon, M.; Sollerman, J.; Smartt, S.; Vinkó, J.; Wheeler, J. C.

    2013-01-01

    We present observations of the unusual optical transient SN 2010U, including spectra taken 1.03 days to 15.3 days after maximum light that identify it as a fast and luminous Fe II type nova. Our multi-band light curve traces the fast decline (t 2 = 3.5 ± 0.3 days) from maximum light (M V = –10.2 ± 0.1 mag), placing SN 2010U in the top 0.5% of the most luminous novae ever observed. We find typical ejecta velocities of ≈1100 km s –1 and that SN 2010U shares many spectral and photometric characteristics with two other fast and luminous Fe II type novae, including Nova LMC 1991 and M31N-2007-11d. For the extreme luminosity of this nova, the maximum magnitude versus rate of decline relationship indicates a massive white dwarf (WD) progenitor with a low pre-outburst accretion rate. However, this prediction is in conflict with emerging theories of nova populations, which predict that luminous novae from massive WDs should preferentially exhibit an alternate spectral type (He/N) near maximum light.

  7. Classical and Recurrent Novae as Quintessential Panchromatic Transients

    Science.gov (United States)

    Mukai, K.; Nelson, T.; Chomiuk, L.; Finzell, T.; Linford, J.; Mioduszewski, A.; Rupen, M.; Sokoloski, J.; Weston, J.

    2014-07-01

    In classical and recurrent novae, thermonuclear runaway (TNR) of accreted material on the white dwarf surface results in ejection of 10^{-6} to 10^{-4} solar masses at velocities of order 1000 km s^{-1}. They are routinely detected as transients from X-rays to radio, and 6 novae (so far) have also been detected in GeV gamma-rays with Fermi/LAT. It appears that all the nearby novae are detected with Fermi, suggesting gamma-ray emission to be a universal property of novae, while a few exceptional novae further away are also detected, indicating that the gamma-ray luminosity of novae varies from system to system. Here we present selected results from our multi-wavelength observations of recent classical and recurrent novae and discuss evidence for multiple, discrete mass ejection episodes driven by a single TNR. The collision among these shells create shocks that can be observed through synchrotron radio emission and optically thin, thermal, hard X-ray emission. We do not find obvious correlation between the X-ray flux and the GeV flux, even though the latter must also result from shocks. It is clear that shocks can either be efficient particle accelerator or efficient thermal X-ray emitter, but not necessarily both at the same time.

  8. Safety and Effectiveness of NovaSure® Endometrial Ablation After Placement of Essure® Micro-Inserts.

    Science.gov (United States)

    Basinski, Cindy M; Price, Pamela; Burkhart, Jamie; Johnson, Jamie

    2012-04-01

    Objective: In-office NovaSure ® after Essure ® is a clinical paradigm for which physicians are seeking information. A PubMed search (July 2011) revealed no peer-reviewed articles describing this treatment sequence. To address the paucity of data on this topic, patients who had undergone Essure followed by NovaSure in a private practice office between July 1, 2008 and December 31, 2009 were evaluated. The objective was to evaluate safety and feasibility of in-office NovaSure after Essure, and to determine if the effectiveness of either procedure was altered by this treatment sequence. Design: This was a retrospective cohort study of 117 women (ages 24-52). Methods: Patients underwent Essure followed by NovaSure in two in-office sessions, separated by a median of 14 days. All patients had menorrhagia and desired permanent sterilization. A postprocedure patient questionnaire was administered to assess satisfaction and perceived effectiveness. Results: Among patients who underwent Essure followed by NovaSure, 83/117 (71%) returned for a 3-month hysterosalpingogram (HSG). Satisfactory placement and tubal occlusion were noted in 79/83 (95%) of these patients. Amenorrhea or spotting was observed in 72/97 (74%) of patients, 22/97 (23%) reported a satisfactory decrease in menstrual flow, and 3/97 (3%) reported ablation failure. Essure followed by NovaSure did not decrease the effectiveness of either procedure, and no adverse events were attributed to the combination of the two procedures. Patients reported high levels of satisfaction with both procedures. Conclusions: In women seeking permanent birth control and menorrhagia reduction, in-office Essure followed by NovaSure appeared to be safe, effective, and associated with high patient satisfaction. (J GYNECOL SURG 28:1).

  9. Nucleosynthesis and Energy Production in Stars: Bethe's Crowning ...

    Indian Academy of Sciences (India)

    Today we understand that the study of the structure and ... periodically if it is unable to maintain this balance. Cre- ... mon source of energy in our day to day life, could not account for the .... The concept of hydrogen burning and the work on bar-.

  10. Neutron-capture rates for explosive nucleosynthesis: the case of 68Ni(n, γ)69Ni

    Science.gov (United States)

    Spyrou, A.; Larsen, A. C.; Liddick, S. N.; Naqvi, F.; Crider, B. P.; Dombos, A. C.; Guttormsen, M.; Bleuel, D. L.; Couture, A.; Crespo Campo, L.; Lewis, R.; Mosby, S.; Mumpower, M. R.; Perdikakis, G.; Prokop, C. J.; Quinn, S. J.; Renstrøm, T.; Siem, S.; Surman, R.

    2017-04-01

    Neutron-capture reactions play an important role in heavy element nucleosynthesis, since they are the driving force for the two processes that create the vast majority of the heavy elements. When a neutron capture occurs on a short-lived nucleus, it is extremely challenging to study the reaction directly and therefore the use of indirect techniques is essential. The present work reports on such an indirect measurement that provides strong constraints on the 68Ni(n, γ)69Ni reaction rate. This is done by populating the compound nucleus 69Ni via the β decay of 69Co and measuring the γ-ray deexcitation of excited states in 69Ni. The β-Oslo method was used to extract the γ-ray strength function and the nuclear level density. In addition the half-life of 69Co was extracted and found to be in agreement with previous literature values. Before the present results, the 68Ni(n, γ)69Ni reaction was unconstrained and the purely theoretical reaction rate was highly uncertain. The new uncertainty on the reaction rate based on the present experiment (variation between upper and lower limit) is approximately a factor of 3. The commonly used reaction libraries JINA-REACLIB and BRUSLIB are in relatively good agreement with the experimental rate. The impact of the new rate on weak r-process calculations is discussed.

  11. Data Driven Trigger Design and Analysis for the NOvA Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kurbanov, Serdar [Univ. of Virginia, Charlottesville, VA (United States)

    2016-01-01

    This thesis primarily describes analysis related to studying the Moon shadow with cosmic rays, an analysis using upward-going muons trigger data, and other work done as part of MSc thesis work conducted at Fermi National Laboratory. While at Fermilab I made hardware and software contributions to two experiments - NOvA and Mu2e. NOvA is a neutrino experiment with the primary goal of measuring parameters related to neutrino oscillation. This is a running experiment, so it's possible to provide analysis of real beam and cosmic data. Most of this work was related to the Data-Driven Trigger (DDT) system of NOvA. The results of the Upward-Going muon analysis was presented at ICHEP in August 2016. The analysis demonstrates the proof of principle for a low-mass dark matter search. Mu2e is an experiment currently being built at Fermilab. Its primary goal is to detect the hypothetical neutrinoless conversion from a muon into an electron. I contributed to the production and tests of Cathode Strip Chambers (CSCs) which are required for testing the Cosmic Ray Veto (CRV) system for the experiment. This contribution is described in the last chapter along with a short description of the technical work provided for the DDT system of the NOvA experiment. All of the work described in this thesis will be extended by the next generation of UVA graduate students and postdocs as new data is collected by the experiment. I hope my eorts of have helped lay the foundation for many years of beautiful results from Mu2e and NOvA.

  12. Muon Neutrino Disappearance in NOvA with a Deep Convolutional Neural Network Classifier

    Energy Technology Data Exchange (ETDEWEB)

    Rocco, Dominick Rosario [Minnesota U.

    2016-03-01

    The NuMI Off-axis Neutrino Appearance Experiment (NOvA) is designed to study neutrino oscillation in the NuMI (Neutrinos at the Main Injector) beam. NOvA observes neutrino oscillation using two detectors separated by a baseline of 810 km; a 14 kt Far Detector in Ash River, MN and a functionally identical 0.3 kt Near Detector at Fermilab. The experiment aims to provide new measurements of Δm2 and θ23 and has potential to determine the neutrino mass hierarchy as well as observe CP violation in the neutrino sector. Essential to these analyses is the classification of neutrino interaction events in NOvA detectors. Raw detector output from NOvA is interpretable as a pair of images which provide orthogonal views of particle interactions. A recent advance in the field of computer vision is the advent of convolutional neural networks, which have delivered top results in the latest image recognition contests. This work presents an approach novel to particle physics analysis in which a convolutional neural network is used for classification of particle interactions. The approach has been demonstrated to improve the signal efficiency and purity of the event selection, and thus physics sensitivity. Early NOvA data has been analyzed (2.74×1020 POT, 14 kt equivalent) to provide new best- fit measurements of sin2(θ23) = 0.43 (with a statistically-degenerate compliment near 0.60) and |Δm2 | = 2.48 × 10-3 eV2.

  13. Deep Mixing of 3He: Reconciling Big Bang and Stellar Nucleosynthesis

    International Nuclear Information System (INIS)

    Eggleton, P P; Dearborn, D P; Lattanzio, J

    2006-01-01

    Low-mass stars, ∼ 1-2 solar masses, near the Main Sequence are efficient at producing 3 He, which they mix into the convective envelope on the giant branch and should distribute into the Galaxy by way of envelope loss. This process is so efficient that it is difficult to reconcile the low observed cosmic abundance of 3 He with the predictions of both stellar and Big Bang nucleosynthesis. In this paper we find, by modeling a red giant with a fully three-dimensional hydrodynamic code and a full nucleosynthetic network, that mixing arises in the supposedly stable and radiative zone between the hydrogen-burning shell and the base of the convective envelope. This mixing is due to Rayleigh-Taylor instability within a zone just above the hydrogen-burning shell, where a nuclear reaction lowers the mean molecular weight slightly. Thus we are able to remove the threat that 3 He production in low-mass stars poses to the Big Bang nucleosynthesis of 3 He

  14. Convergence of scalar-tensor theories towards general relativity and primordial nucleosynthesis

    International Nuclear Information System (INIS)

    Serna, A; Alimi, J-M; Navarro, A

    2002-01-01

    In this paper, we analyse the conditions for convergence towards general relativity of scalar-tensor gravity theories defined by an arbitrary coupling function α (in the Einstein frame). We show that, in general, the evolution of the scalar field (φ) is governed by two opposite mechanisms: an attraction mechanism which tends to drive scalar-tensor models towards Einstein's theory, and a repulsion mechanism which has the contrary effect. The attraction mechanism dominates the recent epochs of the universe evolution if, and only if, the scalar field and its derivative satisfy certain boundary conditions. Since these conditions for convergence towards general relativity depend on the particular scalar-tensor theory used to describe the universe evolution, the nucleosynthesis bounds on the present value of the coupling function, α 0 , strongly differ from some theories to others. For example, in theories defined by α ∝ |φ| analytical estimates lead to very stringent nucleosynthesis bounds on α 0 (∼ -19 ). By contrast, in scalar-tensor theories defined by α ∝ φ much larger limits on α 0 (∼ -7 ) are found

  15. Recent results in explosive and s-process nucleosynthesis from measurements on radioactive and stable targets

    International Nuclear Information System (INIS)

    Koehler, P.E.; Kaeppeler, F.; Schatz, H.

    1993-01-01

    Measurements of (n,p) and (n,α) cross sections are crucial for a better understanding of many scenarios of nucleosynthesis. Current problems in which such reactions play a roll include the possible synthesis of heavy element during the big bang. The production of several rare isotopes in explosive nucleosynthesis, and a better understanding of the role of the s process in the synthesis of light and intermediate mass nuclei. We have recently completed measurements of several (n,p) and (n,α) cross sections of importance to nuclear astrophysics. The cross sections were measured in the range from thermal energy to approximately 1 MeV by using the white neutron source at the Manuel Lujan, Jr. Neutron Scattering Center (LANSCE) in Los Alamos. We have also made complementary measurements at the Karlsruhe Van de Graaff and at thee Oak Ridge Electron Linear Accelerator (ORELA). We discuss the impact of the results on nuclear astrophysics as well as recent improvements and future plans

  16. Deep mixing of 3He: reconciling Big Bang and stellar nucleosynthesis.

    Science.gov (United States)

    Eggleton, Peter P; Dearborn, David S P; Lattanzio, John C

    2006-12-08

    Low-mass stars, approximately 1 to 2 solar masses, near the Main Sequence are efficient at producing the helium isotope 3He, which they mix into the convective envelope on the giant branch and should distribute into the Galaxy by way of envelope loss. This process is so efficient that it is difficult to reconcile the low observed cosmic abundance of 3He with the predictions of both stellar and Big Bang nucleosynthesis. Here we find, by modeling a red giant with a fully three-dimensional hydrodynamic code and a full nucleosynthetic network, that mixing arises in the supposedly stable and radiative zone between the hydrogen-burning shell and the base of the convective envelope. This mixing is due to Rayleigh-Taylor instability within a zone just above the hydrogen-burning shell, where a nuclear reaction lowers the mean molecular weight slightly. Thus, we are able to remove the threat that 3He production in low-mass stars poses to the Big Bang nucleosynthesis of 3He.

  17. Constraints on lifetime and mass of heavy lepton neutrinos imposed by big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Miyama, Shoken; Sato, Katsuhiko

    1978-01-01

    If there exist massive neutral leptons (heavy neutrinos), they would have been produced in thermal equilibrium in the early stages of the universe. The effects of their presence and decay on the big bang nucleosynthesis are investigated in detail and abundances of the products 4 He, 2 H and 7 Li are compared with the observed cosmic abundances. We have determined a region in the lifetime-mass diagram of the heavy neutrino which should be ruled out in order for the big bang nucleosynthesis not to conflict with observed abundances of the elements. In addition, if a lower limit of the lifetime obtained from the Weinberg-Salam type theory, tau>=6 x 10 7 (1 MeV/m sub(νh)) 5 sec, is assumed, where m sub(νh) is the mass of the heavy neutrino, the mass range of 70 eV< m sub(νh)<10 MeV is ruled out. The other constraints on the mass and the lifetime obtained from astrophysical considerations are also discussed and summarized. (author)

  18. Big Bang nucleosynthesis: Accelerator tests and can Ω/sub B/ really be large

    International Nuclear Information System (INIS)

    Schramm, D.N.

    1987-10-01

    The first collider tests of cosmological theory are now underway. The number of neutrino families in nature, N/sub nu/, plays a key role in elementary particle physics as well as in the synthesis of the light elements during the early evolution of the Universe. Standard Big Bang Nucleosynthesis argues for N/sub nu/ = 3 +- 1. Current limits on N/sub nu/ from the CERN anti pp collider and e + e - colliders are presented and compared to the cosmological bound. Supernova SN 1987A is also shown to give a limit on N/sub nu/ comparable to current accelerator bounds. All numbers are found to be small thus verifying the Big Bang model at an earlier epoch than is possible by traditional astronomical observations. Future measurements at SLC and LEP will further tighten this argument. Another key prediction of the standard Big Bang Nucleosynthesis is that the baryon density must be small (Ω/sub B/ ≤ 0.1). Recent attempts to try to subvert this argument using homogeneities of various types are shown to run afoul of the 7 Li abundance which has now become a rather firm constraint. 18 refs., 2 figs

  19. Convergence of scalar-tensor theories towards general relativity and primordial nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Serna, A [Dept. Fisica y Computacion, Universidad Miguel Hernandez, E03202-Elche (Spain); Alimi, J-M [LAEC, CNRS-UMR 8631, Observatoire de Paris-Meudon, F92195-Meudon (France); Navarro, A [Dept. Fisica, Universidad de Murcia, E30071-Murcia (Spain)

    2002-03-07

    In this paper, we analyse the conditions for convergence towards general relativity of scalar-tensor gravity theories defined by an arbitrary coupling function {alpha} (in the Einstein frame). We show that, in general, the evolution of the scalar field ({phi}) is governed by two opposite mechanisms: an attraction mechanism which tends to drive scalar-tensor models towards Einstein's theory, and a repulsion mechanism which has the contrary effect. The attraction mechanism dominates the recent epochs of the universe evolution if, and only if, the scalar field and its derivative satisfy certain boundary conditions. Since these conditions for convergence towards general relativity depend on the particular scalar-tensor theory used to describe the universe evolution, the nucleosynthesis bounds on the present value of the coupling function, {alpha}{sub 0}, strongly differ from some theories to others. For example, in theories defined by {alpha} {proportional_to} |{phi}| analytical estimates lead to very stringent nucleosynthesis bounds on {alpha}{sub 0}({approx}<10{sup -19}). By contrast, in scalar-tensor theories defined by {alpha} {proportional_to} {phi} much larger limits on {alpha}{sub 0}({approx}<10{sup -7}) are found.

  20. Spectroscopy of poorly known northern dwarf novae. Part. I

    International Nuclear Information System (INIS)

    Bruch, A.

    1989-01-01

    Spectroscopic observations of 12 dwarf novae are presented most of which hitherto unknown spectroscopically. The classifications as dwarf novae could be confirmed in most cases. Two objects remain doubtful: CI UMa and MR Per. The latter has the spectrum of a very late type main sequence star with hydrogen emissions and might be a flare star showing extremely slow flares, while the CI UMa spectrum does not contain any emission line above the noise level. In two dwarf novae - DX And and NS Per - absorption lines of the secondary star are newly detected