Science.gov

Sample records for r process

  1. Physical conditions for the r-process

    SciTech Connect

    Wanajo, S.; Tachibana, T.; Goriely, S.

    2012-11-12

    Recent works show that the r-process can proceed by competition between neutron capture and {beta}-decay in low temperature environments (< 5 Multiplication-Sign 10{sup 8} K; cold r-process) where photo-disintegration plays no role. This is in contrast to the traditional picture of the r-process in high temperature environments ({approx} 1 Multiplication-Sign 10{sup 9} K; hot r-process) where the (n, {gamma})-({gamma}, n) equilibrium holds. In this study, we explore nucleosynthesis calculations based on a site-independent model to elucidate the physical conditions leading to cold and hot r-processes.

  2. Cold r-Process in Supernovae

    NASA Astrophysics Data System (ADS)

    Wanajo, Shinya

    2008-05-01

    The r-process in a low temperature environment is explored, in which the neutron emission by photodisintegration does not play a role. A semi-analytic neutrino-driven wind model is utilized for this purpose. The temperature in a supersonically expanding outflow can quickly drop to a few 108 K, where the (n,?)-(?,n) equilibrium is never achieved during the heavy r-nuclei synthesis. In addition, the neutron capture competes with the ?-decay owing to the low matter density. Despite such non-standard physical conditions, a solar-like r-process abundance curve can be reproduced. The cold r-process predicts, however, the low lead production compared to that expected in the traditional r-process conditions, which can be a possible explanation for the low lead abundances found in a couple of r-process-rich Galactic halo stars.

  3. Neutrino Capture and r-Process Nucleosynthesis

    E-print Network

    Bradley S. Meyer; Gail C. McLaughlin; George M. Fuller

    1998-09-18

    We explore neutrino capture during r-process nucleosynthesis in neutrino-driven ejecta from nascent neutron stars. We focus on the interplay between charged-current weak interactions and element synthesis, and we delineate the important role of equilibrium nuclear dynamics. During the period of coexistence of free nucleons and light and/or heavy nuclei, electron neutrino capture inhibits the r-process. At all stages, capture on free neutrons has a larger impact than capture on nuclei. However, neutrino capture on heavey nuclei by itself, if it is very strong, is also detrimental to the r-process until large nuclear equilibrium clusters break down and the classical neutron-capture phase of the r-process begins. The sensitivity of the r-process to neutrino irradiation means that neutrino-capture effects can strongly constrain the r-process site, neutrino physics, or both. These results apply also to r-process scenarios other than neutrino-heated winds.

  4. R-process Nucleosynthesis in Supernova Explosion

    SciTech Connect

    Saruwatari, M.; Hashimoto, M.; Kotake, K.; Yamada, S.

    2011-10-28

    We investigate the possibility of the r-process during the magnetohydrodynamical (MHD) explosion of supernova in a massive star of 13 M{sub {center_dot}} with the effects of neutrinos included. Contrary to the case of the spherical explosion, jet-like explosion due to the combined effects of rotation and magnetic field lowers the electron fraction significantly inside the layers. We find that the ejected material of low electron fraction responsible for the r-process comes out from the inner deep region of the core that is made up of iron-group nuclei. This leads to the production of the second to third peak in the solar r-process elements. We suggest that there are some variations in the r-process nucleosynthesis according to the initial conditions of rotational and magnetic fields.

  5. Network calculations for r-process nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Petermann, I.; Martínez-Pinedo, G.; Arcones, A.; Hix, W. R.; Keli?, A.; Langanke, K.; Panov, I.; Rauscher, T.; Schmidt, K.-H.; Thielemann, F.-K.; Zinner, N.

    2010-01-01

    The r-process is known to be responsible for the synthesis of about half of the elements heavier than iron, nevertheless its astrophysical site has not yet been clearly ascertained, but observations indicate that at least two possible sites should contribute to the solar system abundance of r-process elements. The r-process being responsible for the production of elements heavier than Z = 56 operates rather robustly always resulting in a similar relative abundance pattern. From the nuclear-physics point of view the r-process requires the knowledge of a large number of reaction rates involving exotic nuclei that are not accessible by experiment and data have to be provided by theoretical predictions. We have developed for the first time a complete database of reaction rates that in addition to neutron-capture rates and ?-decay half-lives includes the dominant reactions that can induce fission (neutron-capture, ?-decay and spontaneous fission) and the corresponding fission yields. In addition, we have implemented these reaction rates in a fully implicit reaction network. The influence of the nuclear physics input constituted in the reaction rates based on the two mass models FRDM and ETFSI and on the astrophysical conditions simulating a cold or hot environment are examined.

  6. Rapid Business Process Discovery (R-BPD)

    NASA Astrophysics Data System (ADS)

    Ghose, Aditya; Koliadis, George; Chueng, Arthur

    Modeling is an important and time consuming part of the Business Process Management life-cycle. An analyst reviews existing documentation and queries relevant domain experts to construct both mental and concrete models of the domain. To aid this exercise, we propose the Rapid Business Process Discovery (R-BPD) framework and prototype tool that can query heterogeneous information resources (e.g. corporate documentation, web-content, code e.t.c.) and rapidly construct proto-models to be incrementally adjusted to correctness by an analyst. This constitutes a departure from building and constructing models toward just editing them. We believe this rapid mixed-initiative modeling will increase analyst productivity by significant orders of magnitude over traditional approaches. Furthermore, the possibility of using the approach in distributed and real-time settings seems appealing and may help in significantly improving the quality of the models being developed w.r.t. being consistent, complete, and concise.

  7. The r-process in Magnetorotational Supernovae

    NASA Astrophysics Data System (ADS)

    Tsujimoto, Takuji; Nishimura, Nobuya

    2015-09-01

    One of the hottest open issues involving the chemical evolution of r-process elements is fast enrichment in the early universe. Clear evidence for the chemical enrichement of r-process elements is seen in the stellar abundances of extremely metal poor stars in the Galactic halo. However, small-mass galaxies are the ideal testbed for studying the evolutionary features of r-process enrichment given the potential rarity of production events yielding heavy r-process elements. Their occurrences become countable and thus an enrichment path due to each event can be found in the stellar abundances. We examine the chemical feature of Eu abundance at an early stage of [Fe/H] ? -2 in the Draco and Sculptor dwarf spheroidal (dSph) galaxies. Accordingly, we constrain the properties of Eu production in the early dSphs. We find that the Draco dSph experienced a few Eu production events, whereas Eu enrichment took place more continuously in the Sculptor dSph due to its larger stellar mass. The event rate of Eu production is estimated to be about one per 100-200 core-collapse supernovae, and a Eu mass of ˜ (1-2) × 10-5M? per single event is deduced by associating this frequency with the observed plateau value of [Eu/H] ˜ -1.3 for [Fe/H] ? -2. The observed plateau implies that early Eu enrichment ceases at [Fe/H] ? -2. Such a selective operation only in low-metallicity stars supports magnetorotational supernovae, which require very fast rotation, as the site of early Eu production. We show that the Eu yields deduced from chemical evolution agree well with the nucleosynthesis results from corresponding supernovae models.

  8. Applied Climate Data Processing Using R

    NASA Astrophysics Data System (ADS)

    Fall, S.; Coulibaly, K. M.

    2011-12-01

    This paper presents a series of climate data processing procedures written in R. The workflows presented show that R can be used as a powerful and flexible tool for climate data analysis. Hourly reanalysis temperature from NASA's Modern Era Retrospective-analysis for Research and Applications (MERRA) were used. MERRA data are individual daily data file in network common data form (NETCDF) with hourly temperature time series. Daily maximum and minimum temperatures are extracted from the individual NETCDF files, and then daily temperature ranges (DTR) are computed. The outputs are concatenated to obtain one single DTR file at daily time scale and written as a new NETCDF. The results can be interpolated and compared to actual observations at specific locations. Also Standard climatology parameters like cosine weighted time series anomalies, linear trends, spatial and temporal patterns (with user-defined thresholds) and computations of mean temperatures over time for each grid location can be carried out. The outputs are written in NetCDF or GIS-ready text file with coordinates for further analysis or advanced GIS (Geographical Information System) mapping. The results and interpretation of these procedures applied to the MERRA data, along with the R scripts used to implement them are also presented.

  9. Astrophysical Models of r-Process Nucleosynthesis: An Update

    E-print Network

    Yong-Zhong Qian

    2012-01-24

    An update on astrophysical models for nucleosynthesis via rapid neutron capture, the r process, is given. A neutrino-induced r process in supernova helium shells may have operated up to metallicities of ~10^-3 times the solar value. Another r-process source, possibly neutron star mergers, is required for higher metallicities.

  10. Astrophysical models of r-process nucleosynthesis: An update

    SciTech Connect

    Qian Yongzhong

    2012-11-12

    An update on astrophysical models for nucleosynthesis via rapid neutron capture, the r process, is given. A neutrino-induced r process in supernova helium shells may have operated up to metallicities of {approx} 10{sup -3} times the solar value. Another r-process source, possibly neutron star mergers, is required for higher metallicities.

  11. Cold r-Process in Neutrino-Driven Winds

    E-print Network

    Shinya Wanajo

    2007-07-21

    The r-process in a low temperature environment is explored, in which the neutron emission by photodisintegration does not play a role (cold r-process). A semi-analytic neutrino-driven wind model is utilized for this purpose. The temperature in a supersonically expanding outflow can quickly drop to a few 10^8 K, where the (n, gamma)-(gamma, n) equilibrium is never achieved during the heavy r-nuclei synthesis. In addition, the neutron capture competes with the beta-decay owing to the low matter density. Despite such non-standard physical conditions for the cold r-process, a solar-like r-process abundance curve can be reproduced. The cold r-process predicts, however, the low lead production compared to that expected in the traditional r-process conditions, which can be a possible explanation for the low lead abundances found in a couple of r-process-rich Galactic halo stars.

  12. Fission Properties for R-Process Nuclei

    SciTech Connect

    Erler, J.

    2012-01-01

    We present a systematics of fission barriers and fission lifetimes for the whole landscape of superheavy elements (SHE), i.e., nuclei with Z 100. The fission lifetimes are also compared with the -decay half-lives. The survey is based on a self-consistent description in terms of the Skyrme-Hartree-Fock (SHF) approach. Results for various different SHF parametrizations are compared to explore the robustness of the predictions. The fission path is computed by quadrupole constrained SHF. The computation of fission lifetimes takes care of the crucial ingredients of the large-amplitude collective dynamics along the fission path, as self-consistent collective mass and proper quantum corrections. We discuss the different topologies of fission landscapes which occur in the realm of SHE (symmetric versus asymmetric fission, regions of triaxial fission, bimodal fission, and the impact of asymmetric ground states). The explored region is extended deep into the regime of very neutron-rich isotopes as they are expected to be produced in the astrophysical r process.

  13. Fission properties for r-process nuclei

    E-print Network

    J. Erler; K. Langanke; H. P. Loens; G. Martínez-Pinedo; P. -G. Reinhard

    2011-12-05

    We present a systematics of fission barriers and fission lifetimes for the whole landscape of super-heavy elements (SHE), i.e. nuclei with Z>100. The fission lifetimes are also compared with the alpha-decay half-lives. The survey is based on a self-consistent description in terms of the Skyrme-Hartree-Fock (SHF) approach. Results for various different SHF parameterizations are compared to explore the robustness of the predictions. The fission path is computed by quadrupole constrained SHF. The computation of fission lifetimes takes care of the crucial ingredients of the large-amplitude collective dynamics along the fission path, as self-consistent collective mass and proper quantum corrections. We discuss the different topologies of fission landscapes which occur in the realm of SHE (symmetric versus asymmetric fission, regions of triaxial fission, bi-modal fission, and the impact of asymmetric ground states). The explored region is extended deep into the regime of very neutron-rich isotopes as they are expected to be produced in the astrophysical r process.

  14. Sensitivity studies for the weak r process: neutron capture rates

    SciTech Connect

    Surman, R.; Mumpower, M.; Sinclair, R.; Jones, K. L.; Hix, W. R.; Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 ; McLaughlin, G. C.

    2014-04-15

    Rapid neutron capture nucleosynthesis involves thousands of nuclear species far from stability, whose nuclear properties need to be understood in order to accurately predict nucleosynthetic outcomes. Recently sensitivity studies have provided a deeper understanding of how the r process proceeds and have identified pieces of nuclear data of interest for further experimental or theoretical study. A key result of these studies has been to point out the importance of individual neutron capture rates in setting the final r-process abundance pattern for a ‘main’ (A ? 130 peak and above) r process. Here we examine neutron capture in the context of a ‘weak’ r process that forms primarily the A ? 80 r-process abundance peak. We identify the astrophysical conditions required to produce this peak region through weak r-processing and point out the neutron capture rates that most strongly influence the final abundance pattern.

  15. THE RARE EARTH PEAK: AN OVERLOOKED r-PROCESS DIAGNOSTIC

    SciTech Connect

    Mumpower, Matthew R.; McLaughlin, G. C.; Surman, Rebecca E-mail: gail_mclaughlin@ncsu.edu

    2012-06-20

    The astrophysical site or sites responsible for the r-process of nucleosynthesis still remains an enigma. Since the rare earth region is formed in the latter stages of the r-process, it provides a unique probe of the astrophysical conditions during which the r-process takes place. We use features of a successful rare earth region in the context of a high-entropy r-process (S {approx}> 100k{sub B} ) and discuss the types of astrophysical conditions that produce abundance patterns that best match meteoritic and observational data. Despite uncertainties in nuclear physics input, this method effectively constrains astrophysical conditions.

  16. Nuclear Correlations and the r Process A. Arcones*

    E-print Network

    Bertsch George F.

    of a weakened pairing field in the Hartree-Fock-Bogoliubov (HFB) treatment of nuclei near the dripline on the synthesis of heavy elements by the r process. As calculated by Delaroche et al. [Phys. Rev. C 81, 014303 the calculated abundances before the third r-process peak (at mass number A % 195), where the abundances are low

  17. Sensitivity studies for the main r process: ?-decay rates

    SciTech Connect

    Mumpower, M.; Cass, J.; Passucci, G.; Aprahamian, A.; Surman, R.

    2014-04-15

    The pattern of isotopic abundances produced in rapid neutron capture, or r-process, nucleosynthesis is sensitive to the nuclear physics properties of thousands of unstable neutron-rich nuclear species that participate in the process. It has long been recognized that the some of the most influential pieces of nuclear data for r-process simulations are ?-decay lifetimes. In light of experimental advances that have pushed measurement capabilities closer to the classic r-process path, we revisit the role of individual ?-decay rates in the r process. We perform ?-decay rate sensitivity studies for a main (A > 120) r process in a range of potential astrophysical scenarios. We study the influence of individual rates during (n, ?)-(?, n) equilibrium and during the post-equilibrium phase where material moves back toward stability. We confirm the widely accepted view that the most important lifetimes are those of nuclei along the r-process path for each astrophysical scenario considered. However, we find in addition that individual ?-decay rates continue to shape the final abundance pattern through the post-equilibrium phase, for as long as neutron capture competes with ? decay. Many of the lifetimes important for this phase of the r process are within current or near future experimental reach.

  18. Neutrinos, Fission Cycling, and the r-process

    E-print Network

    J. Beun; G. C. McLaughlin; R. Surman; W. R. Hix

    2006-07-26

    It has long been suggested that fission cycling may play an important role in the r-process. Fission cycling can only occur in a very neutron rich environment. In traditional calculations of the neutrino driven wind of the core-collapse supernova, the environment is not sufficiently neutron rich to produce the r-process elements. However, we show that with a reduction of the electron neutrino flux coming from the supernova, fission cycling does occur and furthermore it produces an abundance pattern which is consistent with observed r-process abundance pattern in halo stars. Such a reduction can be caused by active-sterile neutrino oscillations or other new physics.

  19. Neutron capture rates and r-process nucleosynthesis

    E-print Network

    R. Surman; M. Mumpower; G. C. McLaughlin; R. Sinclair; W. R. Hix; K. L. Jones

    2013-08-31

    Simulations of r-process nucleosynthesis require nuclear physics information for thousands of neutron-rich nuclear species from the line of stability to the neutron drip line. While arguably the most important pieces of nuclear data for the r-process are the masses and beta decay rates, individual neutron capture rates can also be of key importance in setting the final r-process abundance pattern. Here we consider the influence of neutron capture rates in forming the A~80 and rare earth peaks.

  20. Constraints on r-process nucleosynthesis in accretion disks

    NASA Technical Reports Server (NTRS)

    Jin, Liping

    1991-01-01

    Systems in which accretion drives an outflow from a region near a compact object may enrich the interstellar medium in r-process elements. A detailed assessment of the efficacy of this mechanism for the r-process is presented here, taking into account the constraints imposed by typical accretion-disk conditions. It is concluded that r-process elements are unlikely to have been made in this way, largely because the total production is too low, by a factor of about 100,000, to explain the observed abundances.

  1. Impact of nuclear fission on r-process nucleosynthesis and origin of solar r-process elements

    NASA Astrophysics Data System (ADS)

    Shibagaki, Shota; Kajino, Toshitaka; Mathews, Grant J.; Chiba, Satoshi

    2015-02-01

    Binary neutron star mergers (NSMs) are expected to be main production sites of r-process elements. Their ejecta are extremely neutron-rich (Ye<0.1), and the r-process path proceeds along the neutron drip line and enters the region of fissile nuclei. In this situation, although superheavy nuclei may be synthesized and the r-process path may reach the island of stability, those are sensitive to theoretical models of nuclear masses and nuclear fission. In this study, we carry out r-process nucleosynthesis simulations in the NSMs. Our new nuclear reaction network code include new theoretical models of nuclear masses and nuclear fission. Our r-process simulation of a binary NSM shows that the final r-process elemental abundances exhibit flat pattern for A˜110-160, and several fission cycling operate in extremely neutron-rich conditions of the NSM. We find that the combination of the NSMs and the magnetorotational supernovae can reproduce the solar r-process elements. We discuss the validity of this interpretation.

  2. Impact of nuclear fission on r-process nucleosynthesis and origin of solar r-process elements

    SciTech Connect

    Shibagaki, Shota; Kajino, Toshitaka; Mathews, Grant J.; Chiba, Satoshi

    2015-02-24

    Binary neutron star mergers (NSMs) are expected to be main production sites of r-process elements. Their ejecta are extremely neutron-rich (Y{sub e}<0.1), and the r-process path proceeds along the neutron drip line and enters the region of fissile nuclei. In this situation, although superheavy nuclei may be synthesized and the r-process path may reach the island of stability, those are sensitive to theoretical models of nuclear masses and nuclear fission. In this study, we carry out r-process nucleosynthesis simulations in the NSMs. Our new nuclear reaction network code include new theoretical models of nuclear masses and nuclear fission. Our r-process simulation of a binary NSM shows that the final r-process elemental abundances exhibit flat pattern for A?110-160, and several fission cycling operate in extremely neutron-rich conditions of the NSM. We find that the combination of the NSMs and the magnetorotational supernovae can reproduce the solar r-process elements. We discuss the validity of this interpretation.

  3. Impact of nuclear mass uncertainties on the $r$-process

    E-print Network

    Martin, Dirk; Nazarewicz, Witold; Olsen, Erik

    2015-01-01

    Nuclear masses play a fundamental role in understanding how the heaviest elements in the Universe are created in the $r$-process. We predict $r$-process nucleosynthesis yields using neutron capture and photodissociation rates that are based on nuclear density functional theory. Using six Skyrme energy density functionals based on different optimization protocols, we determine for the first time systematic uncertainty bands -- related to mass modeling -- for $r$-process abundances in realistic astrophysical scenarios. We find that features of the underlying microphysics make an imprint on abundances especially in the vicinity of neutron shell closures: abundance peaks and troughs are reflected in trends of neutron separation energy. Further advances in nuclear theory and experiments, when linked to observations, will help in the understanding of astrophysical conditions in extreme $r$-process sites.

  4. Barium from a mini r-process in supernovae

    NASA Technical Reports Server (NTRS)

    Heymann, D.

    1983-01-01

    McCulloch and Wasserburg (1978) have reported nonlinear isotopic anomalies in barium for two Ca-Al-rich inclusions of the Allende carbonaceous chondrite, known as EK-1-4-1 and C-1. In an attempt to account for these anomalies, it has been proposed that Ba from an r-process of nucleosynthesis, containing Ba-135 and Ba-137, was injected into the primeval color system but was not totally homogenized. Questions arise in connection with the relations of Xe isotopes in carbonaceous chondrites. This has prompted Heymann and Dziczkaniec (1979, 1980, 1981) to study the formation of r-Xe, r-Kr, and r-Te by the mini r-process which is thought to occur in the O, Ne-rich shells of Type II supernovae. Lee et al. (1979) have studied the formation of r-Ba, r-Nd, and r-Sm by the same process. Certain differences regarding the approaches used by Lee et al. and by Heymann and Dziczkaniec make it necessary to restudy the work of Lee et al. Attention is given to the survival probabilities of nuclear species of interest, taking into accounts the elements Cs, Ba, I, and Xe.

  5. EPA 402-R-96-014 STABILIZATION/SOLIDIFICATION PROCESSES

    E-print Network

    EPA 402-R-96-014 June 1996 STABILIZATION/SOLIDIFICATION PROCESSES FOR MIXED WASTE Center as conveying, official EPA approval, endorsement, or recommendation. #12;iii PREFACE This report contains cannot render a true comparison from one process to another due to the independent tests

  6. Fission Cycling in a Supernova r-process

    E-print Network

    J. Beun; G. C. McLaughlin; R. Surman; W. R. Hix

    2007-07-30

    Recent halo star abundance observations exhibit an important feature of consequence to the r-process: the presence of a main r-process between the second and third peaks which is consistent among halo stars. We explore fission cycling and steady-beta flow as the driving mechanisms behind this feature. The presence of fission cycling during the r-process can account for nucleosynthesis yields between the second and third peaks, whereas the presence of steady-beta flow can account for consistent r-process patterns, robust under small variations in astrophysical conditions. We employ the neutrino-driven wind of the core-collapse supernova to examine fission cycling and steady-beta flow in the r-process. As the traditional neutrino-driven wind model does not produce the required very neutron-rich conditions for these mechanisms, we examine changes to the neutrino physics necessary for fission cycling to occur in the neutrino-driven wind environment, and we explore under what conditions steady-beta flow is obtained.

  7. R-process in Supernovae and Gamma-Ray Bursts

    SciTech Connect

    Kajino, T.; Harikae, S.; Yoshida, T.; Nakamura, K.; Aoki, W.

    2010-05-12

    We study r-process nucleosynthesis in neutrino-driven winds of Type II supernovae (SNe), binary neutron-star mergers, and magneto-hydrodynamic jets in view of recent astronomical observations of r-process elements in metal-deficient stars and new nuclear reaction data. Universality in observed abundance pattern and total ejected yields of the r-elements from single episode of each candidate site are used to identify the astrophysical site of the r-process. Neutrinos play the critical roles in light element synthesis as well as r-process. Elemental abundances are affected strongly by neutrino oscillations (MSW effect) through the SN nu-process nucleosynthesis. We find that unknown neutrino oscillation parameters, i.e. mass hierarchy and mixing angle theta{sub 13}, are simultaneously constrained by the Li/B ratio from SN nucleosynthesis. Gamma ray burst (GRB) nucleosynthesis in contrast is expected to be relatively free from thermal neutrino effects because of black hole (BH) formation instead of neutron star. We find that the abundance pattern is totally different from ordinary SN nucleosynthesis.

  8. The r-process nucleosynthesis: Nuclear physics challenges

    SciTech Connect

    Goriely, S.

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  10. Unraveling the Dust Formation Process in R Dor

    NASA Astrophysics Data System (ADS)

    Van de Sande, M.; Decin, L.; Lombaert, R.; Walsh, C.; Khouri, T.; Li, X.; Millar, T. J.

    2015-12-01

    Using both dynamical and chemical modelling, we derive an accurate abundance profile for the molecule SiO in the stellar wind of R Dor, an O-rich AGB star. SiO plays a key role in the dust formation process in O-rich AGB stars. This method will be applied to additional molecules, with the aim to achieve a detailed overview of the molecular abundance pattern in the wind of R Dor.

  11. Impact of individual nuclear masses on r-process abundances

    DOE PAGESBeta

    Mumpower, M. R.; Surman, R.; Fang, D. -L.; Beard, M.; Möller, P.; Kawano, T.; Aprahamian, A.

    2015-09-15

    We have performed for the first time a comprehensive study of the sensitivity of r-process nucleosynthesis to individual nuclear masses across the chart of nuclides. Using the latest version (2012) of the Finite-Range Droplet Model, we consider mass variations of ±0.5 MeV and propagate each mass change to all affected quantities, including Q values, reaction rates, and branching ratios. We find such mass variations can result in up to an order of magnitude local change in the final abundance pattern produced in an r-process simulation. As a result, we identify key nuclei whose masses have a substantial impact on abundancemore »predictions for hot, cold, and neutron star merger r-process scenarios and could be measured at future radioactive beam facilities.« less

  12. Impact of individual nuclear masses on r -process abundances

    NASA Astrophysics Data System (ADS)

    Mumpower, M. R.; Surman, R.; Fang, D.-L.; Beard, M.; Möller, P.; Kawano, T.; Aprahamian, A.

    2015-09-01

    We have performed for the first time a comprehensive study of the sensitivity of r -process nucleosynthesis to individual nuclear masses across the chart of nuclides. Using the latest version (2012) of the Finite-Range Droplet Model, we consider mass variations of ±0.5 MeV and propagate each mass change to all affected quantities, including Q values, reaction rates, and branching ratios. We find such mass variations can result in up to an order of magnitude local change in the final abundance pattern produced in an r -process simulation. We identify key nuclei whose masses have a substantial impact on abundance predictions for hot, cold, and neutron star merger r -process scenarios and could be measured at future radioactive beam facilities.

  13. The Rare Earth Peak: An Overlooked r-Process Diagnostic

    NASA Astrophysics Data System (ADS)

    Mumpower, Matthew Ryan

    2012-06-01

    Where do the heavy elements in the universe come from? While the basic principles of nucleosynthesis have been established, a definite answer to this and many related questions still eludes us. The 'rapid' neutron capture process or r-process is believed to be responsible for generating roughly half the nuclei with atomic mass A ? 100. However, the astrophysical site of this process still remains uncertain. Still further, nucleosynthesis calculations of this process must rely on theoretical extrapolations as the bulk of nuclides participating in this process are short-lived.We examine the formation and final structure of the rare earth peak (A ˜ 160) of the r-process nucleosynthesis. Since rare earth peak formation does not occur during (n, gamma) ? (gamma, n) equilibrium it is sensitive to the strong interplay between late time thermodynamic evolution and nuclear physics input. We show that under high entropy conditions (S > 100 kB), the rare earth peak forms at late times in the r-process after neutron exhaustion (neutron-to-seed ratio unity or R = 1) as matter decays back to stability. Depending on the conditions the peak forms either because of the pattern of the neutron capture rates or because of the pattern of the separation energies. We use features of a successful rare earth region to discuss the types of astrophysical conditions that produce abundance patterns that best match meteoritic and observational data. Despite uncertainties in nuclear physics input, this method effectively constrains astrophysical conditions. We study the sensitivity of the r-process abundance pattern to neutron capture rates and beta-decay rates in the region. We identify the range of nuclei which are in uential in rare earth peak formation.

  14. The r-, s-, and p-Processes in Nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Meyer, Bradley S.

    1994-01-01

    Burbidge et al (1957) and Cameron (1957) laid out the framework for our understanding of the formation of the heavy nuclei (those nuclei with mass number A approx. greater than 70). From systematics in the solar system abundance distribution, Burbidge et al determined that the heavy nuclei were formed in three distinct nucleosynthetic processes, which they termed the r-, s-, and p-processes. That we still use these terms today is a credit to the soundness of this work done 37 years ago. We may understand how Burbidge et al and Cameron arrived at their conclusions from Figure 1. One population of nuclei, the s-nuclei, shows an abundance distribution with peaks near mass numbers 87, 138, and 208. These nuclei are made in a slow neutron-capture process, the s-process. A rapid neutron-capture process, the r-process, is responsible for the r-nuclei, whose abundance distribution shows peaks at mass numbers 80, 130, and 195. The p-process is responsible for production of the rarer, more proton-rich heavy isotopes (the p-nuclei) that cannot be made by neutron capture. The first quantitative evaluations of the ideas of Burbidge et al and Cameron came to light in the early 1960s with work on the s-process (Clayton et al 1961, Seeger et al 1965) and the r-process (Seeger et al 1965). These calculations further elucidated the mechanisms for heavy-element formation and showed the plausibility of the framework developed in the 1950s. Subsequent work has focused on determining the astrophysical sites where the r-, s-, and p-processes occurred with the help of improved nuclear details, stellar models, and abundances. A goal of this paper is to review the recent progress astrophysicists, astronomers, and physicists have made in these directions and to point out the problems that remain in our understanding of the formation of the heavy nuclei. Another, perhaps deeper, goal is to to seek some understanding of why there are three major processes available to nature for synthesis of heavy elements. It is impossible for a single paper to cover all relevant aspects of the r-, s-, and p-processes; therefore, where possible, references to other reviews are given. Readers should turn to these reviews for more details. Nevertheless, it is hoped that the present paper gives some flavor for the rich field of heavy-element synthesis.

  15. Rosen’s (M,R) system in process algebra

    PubMed Central

    2013-01-01

    Background Robert Rosen’s Metabolism-Replacement, or (M,R), system can be represented as a compact network structure with a single source and three products derived from that source in three consecutive reactions. (M,R) has been claimed to be non-reducible to its components and algorithmically non-computable, in the sense of not being evaluable as a function by a Turing machine. If (M,R)-like structures are present in real biological networks, this suggests that many biological networks will be non-computable, with implications for those branches of systems biology that rely on in silico modelling for predictive purposes. Results We instantiate (M,R) using the process algebra Bio-PEPA, and discuss the extent to which our model represents a true realization of (M,R). We observe that under some starting conditions and parameter values, stable states can be achieved. Although formal demonstration of algorithmic computability remains elusive for (M,R), we discuss the extent to which our Bio-PEPA representation of (M,R) allows us to sidestep Rosen’s fundamental objections to computational systems biology. Conclusions We argue that the behaviour of (M,R) in Bio-PEPA shows life-like properties. PMID:24237684

  16. The r-Process in Black Hole Winds

    E-print Network

    Shinya Wanajo; Hans-Thomas Janka

    2010-06-11

    All the current r-process scenarios relevant to core-collapse supernovae are facing severe difficulties. In particular, recent core-collapse simulations with neutrino transport show no sign of a neutron-rich wind from the proto-neutron star. In this paper, we discuss nucleosynthesis of the r-process in an alternative astrophysical site, "black hole winds", which are the neutrino-driven outflow from the accretion torus around a black hole. This condition is assumed to be realized in double neutron star mergers, neutron star - black hole mergers, or hypernovae.

  17. Ribonucleoproteins in Archaeal Pre-rRNA Processing and Modification

    PubMed Central

    Yip, W. S. Vincent; Vincent, Nicholas G.; Baserga, Susan J.

    2013-01-01

    Given that ribosomes are one of the most important cellular macromolecular machines, it is not surprising that there is intensive research in ribosome biogenesis. Ribosome biogenesis is a complex process. The maturation of ribosomal RNAs (rRNAs) requires not only the precise cleaving and folding of the pre-rRNA but also extensive nucleotide modifications. At the heart of the processing and modifications of pre-rRNAs in Archaea and Eukarya are ribonucleoprotein (RNP) machines. They are called small RNPs (sRNPs), in Archaea, and small nucleolar RNPs (snoRNPs), in Eukarya. Studies on ribosome biogenesis originally focused on eukaryotic systems. However, recent studies on archaeal sRNPs have provided important insights into the functions of these RNPs. This paper will introduce archaeal rRNA gene organization and pre-rRNA processing, with a particular focus on the discovery of the archaeal sRNP components, their functions in nucleotide modification, and their structures. PMID:23554567

  18. The r-, s-, and p-Processes in Nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Meyer, Bradley S.

    1994-01-01

    A goal of this paper is to review the recent progress astrophysicists, astronomers, and physicists have made in the r-, s-, and p-processes in nucleosynthesis and to point out the problems that remain in our understanding of the formation of the heavy nuclei. Another, perhaps deeper, goal is to to seek some understanding of why there are three major processes available to nature for synthesis of heavy elements.

  19. Explosive Nucleosynthesis and the Astrophysical rProcess

    E-print Network

    Rauscher, Thomas

    Explosive Nucleosynthesis and the Astrophysical r­Process F.­K. Thielemann 1 , C. Freiburghaus 1 in explosive burning and the role which neutron and/or proton separation energies play. We focus neutron stars after a supernova explosion, followed the expansion of matter with initial entropies

  20. Extinct Radioactivities and the R-Process Jet

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.

    2001-01-01

    All extinct radioactive species in the solar nebula were injected from a core-collapse supernova. I discuss primarily the products expected from an r-process jet in this supernova, and various supporting astrophysical observations. Additional information is contained in the original extended abstract.

  1. Nuclear Physics Data Relevant to r-Process Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Kratz, K.-L.; Ostrowski, A. N.; Pfeiffer, B.

    2005-05-01

    The production of about half of the heavy elements in nature occurs via the r-process, i.e., a combination of rapid neutron captures, inverse photodisintegrations, and slower ?-decays, ?-delayed processes as well as fission and possibly interactions with neutrino fluxes. A correct understanding and modelling of this nucleosynthesis process requires the knowledge of nuclear properties far from stability and a detailed description of the astrophysical environments. Experiments at radioactive ion beam facilities have played a pioneering role in exploring the characteristics of nuclear structure in terms of masses and ?-decay properties. Initial examinations paid attention to short-lived ``waiting-point'' nuclei with magic neutron numbers related to the location and height of the solar-system r-process abundance peaks, while more recent activities, mainly in the 132Sn region, focus on the evolution of shell effects as a function of isospin. In this context, shape transitions and the erosion of the classical shell gaps with possible occurrence of new magic numbers play an important role. Consequences of improved theoretical and experimental nuclear data on calculations of the r-process matter flow will be presented, and the applicability of the long-lived actinides 232Th and 238U as cosmo-chronometers will be discussed.

  2. Some Nucleosynthesis Effects Associated with r-Process Jets

    NASA Astrophysics Data System (ADS)

    Cameron, A. G. W.

    2003-04-01

    In a recent work, I have discussed some of the consequences of including rotation and magnetic fields in a model of a core-collapse supernova. Rotation produces equatorial flattening in the resultant neutron star and also produces a surrounding accretion disk. Magnetic fields wrap into a toroid that extrudes material in the equatorial plane. The combination of these effects is an accretion-extrusion disk that feeds material into bipolar jets rooted in the disk where the inward and outward flows meet. The extrusion flow is the site of an r-process in which the seed nuclei embedded in the neutron Fermi sea in the outer neutron star envelope capture the neutrons in which they are embedded. At high latitudes on the neutron star a large neutrino-antineutrino flux drives a neutron wind of the type previously discussed for spherical models, and this is a separate site for a less efficient r-process. In the high-temperature accretion disk, nuclear statistical equilibrium exists, with an abundance peak near mass number 90. The jets are expected to have a velocity of about 0.5c (140 MeV nucleon-1) and to blast holes in the expanding envelope of the supernova, causing large secondary explosions and extensive spallation of both the envelope and jet nuclei. The general purpose of this paper is to discuss nuclear processes and effects associated with this rather complicated scenario and to identify features in the nuclidic abundances in solar system materials that are probably associated with these effects. One discussion tentatively identifies the fission point for r-process fission recycling with the nuclide 297Bh and argues for fission peaks around mass numbers 132 and 165, identifying the latter with an r-process abundance hump in the rare earth region. The equilibrium abundance peak at mass number 90 should be involved in creating the abundance peak in the p-process in that region, previously not understood. Spallation of r-process nuclei near the mass number 132 peak can be identified with an unusual Xe component in interstellar nanodiamonds called Xe-HL. A discussion is given of other isotopic anomalies in meteoritic components that imply mixing and turbulence in the expanding supernova envelope, and it identifies the macroscopic calcium-aluminum inclusions in meteorites as originating in the envelope of a supernova responsible for triggering formation of the primitive solar nebula. Spallation can also be expected to produce DLiBeB fragments in the CO and He layers of the envelope as a primary process, in contrast to cosmic-ray production of such fragments in secondary processes.

  3. Process rc es r e o re o r s or o ro c o e oor o o s r e s e s

    E-print Network

    Process rc es r e o re o r s or o ro c o e oor o o s r e s e s Abstract str b t r s rts c ab rat r c ss s c s act t s c t s c r at a c r at t act t s a t a a art t t sta rs t r c ss s a ss t a c aract r st c r s bas t c c t a r c ss scr b t r c ss t b a ac t s c ct t r t r c ss act t r s rt a t r

  4. ?-decay spectroscopy for the r-process nucleosynthesis

    SciTech Connect

    Nishimura, Shunji; Collaboration: RIBF Decay Collaborations

    2014-05-09

    Series of decay spectroscopy experiments, utilizing of high-purity Ge detectors and double-sided silicon-strip detectors, have been conducted to harvest the decay properties of very exotic nuclei relevant to the r-process nucleosynthesis at the RIBF. The decay properties such as ?-decay half-lives, low-lying states, ?-delayed neutron emissions, isomeric states, and possibly Q{sub ?} of the very neutron-rich nuclei are to be measured to give significant constraints in the uncertainties of nuclear properties for the r-process nucleosynthesis. Recent results of ?? spectroscopy study using in-flight fission of {sup 238}U-beam will be presented together with our future perspectives.

  5. Probabilities of delayed processes for nuclei involved in the r-process

    SciTech Connect

    Panov, I. V.; Korneev, I. Yu.; Lutostansky, Yu. S.; Thielemann, F.-K.

    2013-01-15

    Delayed fission, along with induced and spontaneous fission, is responsible for the suppression of the production of superheavy elements both during the r-process and after its completion. Beta-decay strength functions are required for calculating delayed fission. In the present study, respective strength functions are calculated by relying on the theory of finite Fermi systems and by predominantly employing nuclear masses and fission barriers predicted by a generalized Thomas-Fermi model. The probabilities for delayed fission and for the emission of delayed neutrons are calculated for a number of isotopes. On the basis of calculations performed in order to determine the probabilities for delayed processes, it is shown that some of the delayed-fission probabilities calculated thus far were substantially overestimated. The application of these new results to calculating the r-process may change substantially both the r-process path and the yields of superheavy nuclei.

  6. Assessment of advanced coal-gasification processes. [AVCO high throughput gasification in process; Bell High Mass Flux process; CS-R process; and Exxon Gasification process

    SciTech Connect

    McCarthy, J.; Ferrall, J.; Charng, T.; Houseman, J.

    1981-06-01

    This report represents a technical assessment of the following advanced coal gasification processes: AVCO High Throughput Gasification (HTG) Process, Bell Single - Stage High Mass Flux (HMF) Process, Cities Service/Rockwell (CS/R) Hydrogasification Process, and the Exxon Catalytic Coal Gasification (CCG) Process. Each process is evaluated for its potential to produce SNG from a bituminous coal. In addition to identifying the new technology these processes represent, key similarities/differences, strengths/weaknesses, and potential improvements to each process are identified. The AVCO HTG and the Bell HMF gasifiers share similarities with respect to: short residence time (SRT), high throughput rate, slagging and syngas as the initial raw product gas. The CS/R Hydrogasifier is also SRT but is non-slagging and produces a raw gas high in methane content. The Exxon CCG gasifier is a long residence time, catalytic fluidbed reactor producing all of the raw product methane in the gasifier.

  7. Some Properties of r-Process Accretion Disks and Jets

    NASA Astrophysics Data System (ADS)

    Cameron, A. G. W.

    2001-11-01

    In a core-collapse supernova event a rapidly rotating neutron star is formed (in the more massive stars this may subsequently collapse to a black hole). Recent studies have indicated that an intrinsic feature of the subsequent explosion is the flood of neutrinos and antineutrinos (of the three flavors) that will heat and transfer momentum to the overlying envelope and expel it. They are also expected to expel a neutron-dominated plasma in a wind from the surface of a simple neutron star lacking rotation and magnetic fields. However, because of the rapid rotation, the magnetic field that connects the neutron star to the overlying envelope should be wrapped into a toroid and the ejected plasma should be incorporated into the accretion disk formed around the star. Simulations of collapsing stellar cores have also shown that rotational flattening will produce a small accretion disk. Such accretion disks in astrophysical objects always appear to form a pair of axial jets. Here the disk plasma should be accelerated out of the disk in the jets with a velocity of the order of 0.5c. The operation of the r-process in this kind of accretion disk and the ejection of the products in the jets has been studied. The critical density in the accretion disk lies in the range 1011-1013 gm cm-3, where nuclear statistical equilibrium (with balance between beta decay and capture) maintains the nuclei well beyond the conventional neutron drip line, with free neutron/nucleus ratios in the tens to the thousands. The r-process takes place while this material moves toward the base of the jets and beta imbalance allows the proton charge number to increase at a rate of several per second. The plasma coming from the higher densities undergoes fission recycling and produces nuclei mainly at and above A=132, while the plasma from lower densities produces the lower part of the r-process yields. The jets should also expel material from the still lower density part of the disk in which no r-process has occurred. The interaction of the jets with the surrounding expanding supernova envelope is discussed. Phenomena here involve the spallation formation of the LiBeB elements and the formation of deuterium by similar spallation on helium or by neutron diffusion out of the jets if there is an outer hydrogen region in the expanding envelope. This is probably the origin of the 10Be found as an extinct radioactivity in primitive solar system material, arising from the core-collapse supernova that appears to have triggered the collapse of a molecular cloud core to form the primitive solar nebula, and of the deuterium enhancement at the galactic central region of star formation. The jets constitute a natural way to produce the large variations in abundances detected in the youngest generation of stars. The r-process jets are identified with the gamma-ray bursters as a result of diffusion of gamma rays from the jets, arising from beta decay of the r-process products, and their afterglows are identified with the interactions of the jets in penetrating through the supernova envelopes.

  8. MODISTools – downloading and processing MODIS remotely sensed data in R

    PubMed Central

    Tuck, Sean L; Phillips, Helen RP; Hintzen, Rogier E; Scharlemann, Jörn PW; Purvis, Andy; Hudson, Lawrence N

    2014-01-01

    Remotely sensed data – available at medium to high resolution across global spatial and temporal scales – are a valuable resource for ecologists. In particular, products from NASA's MODerate-resolution Imaging Spectroradiometer (MODIS), providing twice-daily global coverage, have been widely used for ecological applications. We present MODISTools, an R package designed to improve the accessing, downloading, and processing of remotely sensed MODIS data. MODISTools automates the process of data downloading and processing from any number of locations, time periods, and MODIS products. This automation reduces the risk of human error, and the researcher effort required compared to manual per-location downloads. The package will be particularly useful for ecological studies that include multiple sites, such as meta-analyses, observation networks, and globally distributed experiments. We give examples of the simple, reproducible workflow that MODISTools provides and of the checks that are carried out in the process. The end product is in a format that is amenable to statistical modeling. We analyzed the relationship between species richness across multiple higher taxa observed at 526 sites in temperate forests and vegetation indices, measures of aboveground net primary productivity. We downloaded MODIS derived vegetation index time series for each location where the species richness had been sampled, and summarized the data into three measures: maximum time-series value, temporal mean, and temporal variability. On average, species richness covaried positively with our vegetation index measures. Different higher taxa show different positive relationships with vegetation indices. Models had high R2 values, suggesting higher taxon identity and a gradient of vegetation index together explain most of the variation in species richness in our data. MODISTools can be used on Windows, Mac, and Linux platforms, and is available from CRAN and GitHub (https://github.com/seantuck12/MODISTools). PMID:25558360

  9. MODISTools - downloading and processing MODIS remotely sensed data in R.

    PubMed

    Tuck, Sean L; Phillips, Helen Rp; Hintzen, Rogier E; Scharlemann, Jörn Pw; Purvis, Andy; Hudson, Lawrence N

    2014-12-01

    Remotely sensed data - available at medium to high resolution across global spatial and temporal scales - are a valuable resource for ecologists. In particular, products from NASA's MODerate-resolution Imaging Spectroradiometer (MODIS), providing twice-daily global coverage, have been widely used for ecological applications. We present MODISTools, an R package designed to improve the accessing, downloading, and processing of remotely sensed MODIS data. MODISTools automates the process of data downloading and processing from any number of locations, time periods, and MODIS products. This automation reduces the risk of human error, and the researcher effort required compared to manual per-location downloads. The package will be particularly useful for ecological studies that include multiple sites, such as meta-analyses, observation networks, and globally distributed experiments. We give examples of the simple, reproducible workflow that MODISTools provides and of the checks that are carried out in the process. The end product is in a format that is amenable to statistical modeling. We analyzed the relationship between species richness across multiple higher taxa observed at 526 sites in temperate forests and vegetation indices, measures of aboveground net primary productivity. We downloaded MODIS derived vegetation index time series for each location where the species richness had been sampled, and summarized the data into three measures: maximum time-series value, temporal mean, and temporal variability. On average, species richness covaried positively with our vegetation index measures. Different higher taxa show different positive relationships with vegetation indices. Models had high R (2) values, suggesting higher taxon identity and a gradient of vegetation index together explain most of the variation in species richness in our data. MODISTools can be used on Windows, Mac, and Linux platforms, and is available from CRAN and GitHub (https://github.com/seantuck12/MODISTools). PMID:25558360

  10. r-Process Lanthanide Production and Heating Rates in Kilonovae

    E-print Network

    Lippuner, Jonas

    2015-01-01

    r-Process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the material after nuclear burning ceases, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. (2013, ApJ, 774, 25) and Tanaka & Hotokezaka (2013, ApJ, 775, 113) pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions $Y_e$, initial specific entropies $s$, and expansion timescales $\\tau$. We find that the ejecta is lanthanide-free for $Y_e \\gtrsim 0.22 - 0.30$, depending on $s$ and $\\tau$. The heating rate is insensitive to $s$ and $\\tau$, but certain, larger values of $Y_e$ lead to reduced heating rates, due to individual nuclides dominating the heating. With a...

  11. r-process Lanthanide Production and Heating Rates in Kilonovae

    NASA Astrophysics Data System (ADS)

    Lippuner, Jonas; Roberts, Luke F.

    2015-12-01

    r-process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. and Tanaka & Hotokezaka pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions Ye, initial specific entropies s, and expansion timescales ?. We find that the ejecta is lanthanide-free for Ye ? 0.22-0.30, depending on s and ?. The heating rate is insensitive to s and ?, but certain, larger values of Ye lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing Ye, but the light-curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and 100 days, and we provide a simple fit in Ye, s, and ? to estimate whether or not the ejecta is lanthanide-rich.

  12. Nucleon-Alpha Particle Disequilibrium and Short-Lived r-Process Radioactivities

    NASA Technical Reports Server (NTRS)

    Meyer, B. S.; Clayton, D. D.; Chellapilla, S.; The, L.-S.

    2002-01-01

    r-Process yields can be extremely sensitive to expansion parameters when a persistent disequilibrium between free nucleons and alpha particles is present. This may provide a natural scenario for understanding the variation of heavy and light r-process isotopes in different r-process events. Additional information is contained in the original extended abstract.

  13. All-optical packet switching with all-optical header processing and 2R regeneration

    E-print Network

    Wai, Ping-kong Alexander

    CTuF1 All-optical packet switching with all-optical header processing and 2R regeneration L. F. K demonstrate a 1×4 10 Gb/s all-optical packet switch with all-optical header processing and 2R regeneration switching with all-optical header processing and all-optical 2R regeneration (reshaping and re

  14. Mass measurements along the r-process path at CARIBU

    NASA Astrophysics Data System (ADS)

    Savard, Guy; Clark, Jason; van Schelt, Jon; Lascar, Dan; Levand, Anthony; Zabransky, Bruce; Sharma, Kumar

    2012-10-01

    The CARIBU facility is now operational and a large body of new mass measurements around the N=82 waiting point has been accumulated. The masses of over 70 neutron-rich isotopes from the heavy Californium fission peak have been measured with the CPT Penning trap mass spectrometer yielding a typical accuracy of 10 keV/c2. The most neutron-rich masses show significant deviations from either masses measured by other means when available or from extrapolated values from the last Atomic Mass Evaluation when no measurements where available. The system used for these measurements will be briefly described and an analysis of the modification to the delay for the r-process in this region when taking into accounts the new masses will be presented.

  15. The r-process and neutrino-heated supernova ejecta

    NASA Technical Reports Server (NTRS)

    Woosley, S. E.; Wilson, J. R.; Mathews, G. J.; Hoffman, R. D.; Meyer, B. S.

    1994-01-01

    As a neutron star is formed by the collapse of the iron core of a massive star, its Kelvin-Helmholtz evolution is characterized by the release of gravitational binding energy as neutrinos. The interaction of these neutrinos with heated material above the neutron star generates a hot bubble in an atmosphere that is nearly in hydrostatic equilibrium and heated, after approximately 10 s, to an entropy of S/N(sub AS)k greater than or approximately = 400. The neutron-to-proton ratio for material moving outward through this bubble is set by the balance between neutrino and antineutrino capture on nucleons. Because the electron antineutrino spectrum at this time is hotter than the electron neutrino spectrum, the bubble is neutron-rich (0.38 less than or approximately = Y(sub e) less than or approximately = 0.47). Previous work using a schematic model has shown that these conditions are well suited to the production of heavy elements by the r-process. In this paper we have advanced the numerical modeling of a 20 solar mass 'delayed' supernova explosion to the point that we can follow the detailed evolution of material moving through the bubble at the late times appropiate to r-process nucleosynthesis. The supernova model predicts a final kinetic energy for the ejecta of 1.5 x 10(exp 51) ergs and leaves behind a remnant with a baryon mass of 1.50 solar mass (and a gravitational mass of 1.445 solar mass). We follow the thermodynamic and compositional evolution of 40 trajectories in rho(t), T(t), Y(sub e)(t) for a logarithmic grid of mass elements for the last approximately = 0.03 solar mass to be ejected by the proto-neutron star down to the last less than 10(exp -6) solar mass of material expelled at up to approximately = 18 s after core collapse. We find that an excellent fit to the solar r-process abundance distribution is obtained with no adjustable parameters in the nucleosynthesis calculations. Moreover, the abundances are produced in the quantities required to account for the present Galactic abundances. However, at earlier times, this one-dimensional model ejects too much material with entropies S/N(sub A)k approximately 50 and Y(sub e) approximately 0.46. This leads to an acceptable over production of N = 50 nuclei, particularly Sr-88, Y-89, and Zr-90, relative to their solar abundances. We speculate on various means to avoid the early overproduction and/or ejection of N = 50 isotonic nuclei while still producing and ejecting the correct amount of r-process material.

  16. The r-Process in Metal Poor Stars and Black Hole Formation

    E-print Network

    Richard Boyd; Michael Famiano; Bradley Meyer; Yuko Motizuki; Toshitaka Kajino; Ian Roederer

    2011-11-16

    Nucleosynthesis of heavy nuclei in metal-poor stars is generally thought to occur via the r-process because the r-process is a primary process that would have operated early in the Galaxy's history. This idea is strongly supported by the fact that the abundance pattern in many metal-poor stars matches well the inferred Solar r-process abundance pattern in the mass range between the second and third r-process abundance peaks. Nevertheless, a significant number of metal-poor stars do not share this standard r-process template. In this Letter we suggest that the nuclides observed in many of these stars are produced by the r-process, but that it is prevented from running to completion in more massive stars by collapse to black holes before the r-process is completed, creating a "truncated r-process," or "tr-process." We find that the observed fraction of tr-process stars is qualitatively what one would expect from the initial mass function, and that an apparent sharp truncation observed at around mass 160 could result from a combination of collapses to black holes and the difficulty of observing the higher mass rare earths. We test the tr-process hypothesis with r-process calculations that are terminated before all r-process trajectories have been ejected. We find qualitative agreement between observation and theory when black hole collapse and observational realities are taken into account.

  17. THE r-PROCESS IN METAL-POOR STARS AND BLACK HOLE FORMATION

    SciTech Connect

    Boyd, R. N.; Famiano, M. A.; Meyer, B. S.; Motizuki, Y.; Kajino, T.; Roederer, I. U.

    2012-01-15

    Nucleosynthesis of heavy nuclei in metal-poor stars is generally thought to occur via the r-process because the r-process is a primary process that would have operated early in the Galaxy's history. This idea is strongly supported by the fact that the abundance pattern in many metal-poor stars matches well the inferred solar r-process abundance pattern in the mass range between the second and third r-process abundance peaks. Nevertheless, a significant number of metal-poor stars do not share this standard r-process template. In this Letter, we suggest that the nuclides observed in many of these stars are produced by the r-process, but that it is prevented from running to completion in more massive stars by collapse to black holes before the r-process is completed, creating a 'truncated r-process', or 'tr-process'. We find that the observed fraction of tr-process stars is qualitatively what one would expect from the initial mass function and that an apparent sharp truncation observed at around mass 160 could result from a combination of collapses to black holes and the difficulty of observing the higher mass rare-earth elements. We test the tr-process hypothesis with r-process calculations that are terminated before all r-process trajectories have been ejected. We find qualitative agreement between observation and theory when black hole collapse and observational realities are taken into account.

  18. Windings of Planar Stable Processes R. A. Doney & D. A. Korshunov

    E-print Network

    Sidorov, Nikita

    Windings of Planar Stable Processes R. A. Doney & D. A. Korshunov First version: 2 April 2012 of Manchester #12;Windings of planar stable processes R.A. Doney and S. Vakeroudis March 16, 2012 )>IJH) for the (well-dened) winding process associated to our planar stable process. AMS 2010 subject classication

  19. C. R. Mecanique 331 (2003) 515523 Mixing is an aggregation process

    E-print Network

    Duplat, Jérôme

    2003-01-01

    auto-convolution. Pour citer cet article : E. Villermaux, J. Duplat, C. R. Mecanique 331 (2003). 2003C. R. Mecanique 331 (2003) 515­523 Mixing is an aggregation process Emmanuel Villermaux a , Jérôme of concentration distributions stable by self-convolution. To cite this article: E. Villermaux, J. Duplat, C. R

  20. Estimating R-Process Yields from Abundances of the Metal-Poor Stars

    E-print Network

    Li, Hongjie; Cui, Wenyuan; Zhang, Bo

    2014-01-01

    The chemical abundances of metal-poor stars provide important clues to explore stellar formation history and set significant constraints on models of the r-process. In this work, we find that the abundance patterns of the light and iron group elements of the main r-process stars are very close to those of the weak r-process stars. Based on a detailed abundance comparison, we find that the weak r-process occurs in supernovae with a progenitor mass range of $\\sim11-26M_{\\odot}$. Using the SN yields given by Heger & Woosley and the abundances of the weak r-process stars, the weak r-process yields are derived. The SNe with a progenitor mass range of $15M_{\\odot}r-process and their contributions are larger than 80%. Using the abundance ratios of the weak r-process and the main r-process in the solar system, the average yields of the main r-process are estimated. The observed correlations of the [neutron-capture/Eu] versus [Eu/Fe] can be explained by mixing o...

  1. The impact of global nuclear mass model uncertainties on $r$-process abundance predictions

    E-print Network

    M. Mumpower; R. Surman; A. Aprahamian

    2014-11-14

    Rapid neutron capture or `$r$-process' nucleosynthesis may be responsible for half the production of heavy elements above iron on the periodic table. Masses are one of the most important nuclear physics ingredients that go into calculations of $r$-process nucleosynthesis as they enter into the calculations of reaction rates, decay rates, branching ratios and Q-values. We explore the impact of uncertainties in three nuclear mass models on $r$-process abundances by performing global monte carlo simulations. We show that root-mean-square (rms) errors of current mass models are large so that current $r$-process predictions are insufficient in predicting features found in solar residuals and in $r$-process enhanced metal poor stars. We conclude that the reduction of global rms errors below $100$ keV will allow for more robust $r$-process predictions.

  2. The impact of global nuclear mass model uncertainties on r-process abundance predictions

    NASA Astrophysics Data System (ADS)

    Mumpower, M.; Surman, R.; Aprahamian, A.

    2015-05-01

    Rapid neutron capture or `r-process' nucleosynthesis may be responsible for half the production of heavy elements above iron on the periodic table. Masses are one of the most important nuclear physics ingredients that go into calculations of r-process nucleosynthesis as they enter into the calculations of reaction rates, decay rates, branching ratios and Q-values. We explore the impact of uncertainties in three nuclear mass models on r-process abundances by performing global monte carlo simulations. We show that root-mean-square (rms) errors of current mass models are large so that current r-process predictions are insufficient in predicting features found in solar residuals and in r-process enhanced metal poor stars. We conclude that the reduction of global rms errors below 100 keV will allow for more robust r-process predictions.

  3. R-process nucleosynthesis from an inner explosion of a low mass iron core

    NASA Astrophysics Data System (ADS)

    Nishimura, S.; Hashimoto, M.; Fujimoto, S.

    2005-07-01

    We investigate the r-process that occurs due to the explosion from an inner region of the Fe-core. It is shown that the solar r-process abundances are rather well reproduced for a model of 13 M?. We also examine whether the fission affects final r-process abundances by using the full nuclear reaction network with both spontaneous and the ?-delayed fission included. Moreover, we pay attention how the mass formula affects the r-process peaks by using two networks.

  4. Realistic fission model and the r-process in neutron star mergers

    SciTech Connect

    Shibagaki, S.; Kajino, T.; Chiba, S.; Mathews, G. J.

    2014-05-09

    About half of heavy elements are considered to be produced by the rapid neutron-capture process, r-process. The neutron star merger is one of the viable candidates for the astrophysical site of r-process nucleosynthesis. Nuclear fission reactions play an important role in the r-process of neutron star mergers. However theoretical predictions about fission properties of neutron-rich nuclei have some uncertainties. Especially, their fission fragment distributions are totally unknown and the phenomenologically extrapolated distribution was often applied to nucleosynthesis calculations. In this study, we have carried out r-process nucleosynthesis calculations based upon new theoretical estimates of fission fragment distributions. We discuss the effects on the r-process in neutron star mergers from the nuclear fission of heavy neutron-rich actinide elements. We also discuss how variations in the fission fragment distributions affect the abundance pattern.

  5. Solid-State Lighting: Cantilever Epitaxy Process Wins R&D 100 Award

    SciTech Connect

    2012-04-19

    Sandia National Laboratories received an R&D 100 Award from R&D Magazine for development of a new process for growing gallium nitride on an etched sapphire substrate. The process, called cantilever epitaxy, promises to make brighter and more efficient green, blue, and white LEDs.

  6. Detection of the Second r-process Peak Element Tellurium in Metal-Poor Stars

    E-print Network

    Roederer, Ian U; Cowan, John J; Beers, Timothy C; Frebel, Anna; Ivans, Inese I; Schatz, Hendrik; Sobeck, Jennifer S; Sneden, Christopher

    2012-01-01

    Using near-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope, we detect neutral tellurium in three metal-poor stars enriched by products of r-process nucleosynthesis, BD+17 3248, HD 108317, and HD 128279. Tellurium (Te, Z=52) is found at the second r-process peak (A=130) associated with the N=82 neutron shell closure, and it has not been detected previously in Galactic halo stars. The derived tellurium abundances match the scaled solar system r-process distribution within the uncertainties, confirming the predicted second peak r-process residuals. These results suggest that tellurium is predominantly produced in the main component of the r-process, along with the rare earth elements.

  7. DETECTION OF THE SECOND r-PROCESS PEAK ELEMENT TELLURIUM IN METAL-POOR STARS ,

    SciTech Connect

    Roederer, Ian U.; Lawler, James E.; Cowan, John J.; Beers, Timothy C.; Frebel, Anna; Ivans, Inese I.; Schatz, Hendrik; Sobeck, Jennifer S.; Sneden, Christopher

    2012-03-15

    Using near-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, we detect neutral tellurium in three metal-poor stars enriched by products of r-process nucleosynthesis, BD +17 3248, HD 108317, and HD 128279. Tellurium (Te, Z = 52) is found at the second r-process peak (A Almost-Equal-To 130) associated with the N = 82 neutron shell closure, and it has not been detected previously in Galactic halo stars. The derived tellurium abundances match the scaled solar system r-process distribution within the uncertainties, confirming the predicted second peak r-process residuals. These results suggest that tellurium is predominantly produced in the main component of the r-process, along with the rare earth elements.

  8. Sensitivity studies for r-process nucleosynthesis in three astrophysical scenarios

    E-print Network

    R. Surman; M. Mumpower; J. Cass; I. Bentley; A. Aprahamian; G. C. McLaughlin

    2013-08-31

    In rapid neutron capture, or r-process, nucleosynthesis, heavy elements are built up via a sequence of neutron captures and beta decays that involves thousands of nuclei far from stability. Though we understand the basics of how the r-process proceeds, its astrophysical site is still not conclusively known. The nuclear network simulations we use to test potential astrophysical scenarios require nuclear physics data (masses, beta decay lifetimes, neutron capture rates, fission probabilities) for all of the nuclei on the neutron-rich side of the nuclear chart, from the valley of stability to the neutron drip line. Here we discuss recent sensitivity studies that aim to determine which individual pieces of nuclear data are the most crucial for r-process calculations. We consider three types of astrophysical scenarios: a traditional hot r-process, a cold r-process in which the temperature and density drop rapidly, and a neutron star merger trajectory.

  9. New developments in understanding the r-process from observations of metal-poor stars

    NASA Astrophysics Data System (ADS)

    Frebel, Anna

    2015-04-01

    In their atmospheres, old metal-poor Galactic stars retain detailed information about the chemical composition of the interstellar medium at the time of their birth. Extracting such stellar abundances enables us to reconstruct the beginning of the chemical evolution shortly after the Big Bang. About 5% of metal-poor stars with [Fe/H] < - 2 . 5 display in their spectrum a strong enhancement of neutron-capture elements associated with the rapid (r-) nucleosynthesis process that is responsible for the production of the heaviest elements in the Universe. This fortuity provides a unique opportunity of bringing together astrophysics and nuclear physics because these objects act as ``cosmic lab'' for both fields of study. The so-called r-process stars are thought to have formed from material enriched in heavy neutron-capture elements that were created during an r-process event in a previous generation supernova. It appears that the few stars known with this rare chemical signature all follow the scaled solar r-process pattern (for the heaviest elements with 56 <= Z <= 90 that is). This suggests that the r-process is universal - a surprising empirical finding and a solid result that can not be obtained from any laboratory on earth. While much research has been devoted to establishing this pattern, little attention has been given to the overall level of enhancement. New results will be presented on the full extent of r-process element enrichment as observed in metal-poor stars. The challenge lies in determining how the r-process material in the earliest gas clouds was mixed and diluted. Assuming individual r-process events to have contributed the observed r-process elements. We provide empirical estimates on the amount of r-process material produced. This should become a crucial constraint for theoretical nuclear physics models of heavy element nucleosynthesis.

  10. The r-process of stellar nucleosynthesis: Astrophysics and nuclear physics achievements and mysteries

    NASA Astrophysics Data System (ADS)

    Arnould, M.; Goriely, S.; Takahashi, K.

    2007-09-01

    The r-process, or the rapid neutron-capture process, of stellar nucleosynthesis is called for to explain the production of the stable (and some long-lived radioactive) neutron-rich nuclides heavier than iron that are observed in stars of various metallicities, as well as in the solar system. A very large amount of nuclear information is necessary in order to model the r-process. This concerns the static characteristics of a large variety of light to heavy nuclei between the valley of stability and the vicinity of the neutron-drip line, as well as their beta-decay branches or their reactivity. Fission probabilities of very neutron-rich actinides have also to be known in order to determine the most massive nuclei that have a chance to be involved in the r-process. Even the properties of asymmetric nuclear matter may enter the problem. The enormously challenging experimental and theoretical task imposed by all these requirements is reviewed, and the state-of-the-art development in the field is presented. Nuclear-physics-based and astrophysics-free r-process models of different levels of sophistication have been constructed over the years. We review their merits and their shortcomings. The ultimate goal of r-process studies is clearly to identify realistic sites for the development of the r-process. Here too, the challenge is enormous, and the solution still eludes us. For long, the core collapse supernova of massive stars has been envisioned as the privileged r-process location. We present a brief summary of the one- or multidimensional spherical or non-spherical explosion simulations available to-date. Their predictions are confronted with the requirements imposed to obtain an r-process. The possibility of r-nuclide synthesis during the decompression of the matter of neutron stars following their merging is also discussed. Given the uncertainties remaining on the astrophysical r-process site and on the involved nuclear physics, any confrontation between predicted r-process yields and observed abundances is clearly risky. A comparison dealing with observed r-nuclide abundances in very metal-poor stars and in the solar system is attempted on grounds of r-process models based on parametrised astrophysics conditions. The virtues of the r-process product actinides for dating old stars or the solar system are also critically reviewed.

  11. The Hamburg/ESO R-process Enhanced Star survey (HERES). V. Detailed abundance analysis of the r-process enhanced star HE 2327-5642

    E-print Network

    Mashonkina, L; Barklem, P S; Hill, V; Beers, T C; Velichko, A

    2010-01-01

    We report on a detailed abundance analysis of the strongly r-process enhanced giant star, HE 2327-5642 ([Fe/H] = -2.78, [r/Fe] = +0.99). Determination of stellar parameters and element abundances was based on analysis of high-quality VLT/UVES spectra. The surface gravity was calculated from the NLTE ionization balance between Fe I and Fe II, and Ca I and Ca II. Accurate abundances for a total of 40 elements and for 23 neutron-capture elements beyond Sr and up to Th were determined. The heavy element abundance pattern of HE 2327-5642 is in excellent agreement with those previously derived for other strongly r-process enhanced stars. Elements in the range from Ba to Hf match the scaled Solar r-process pattern very well. No firm conclusion can be drawn with respect to a relationship between the fisrt neutron-capture peak elements, Sr to Pd, in HE 2327-5642 and the Solar r-process, due to the uncertainty of the latter. A clear distinction in Sr/Eu abundance ratios was found between the halo stars with different e...

  12. The r-Process in Metal Poor Stars and Black Hole Formation

    SciTech Connect

    Boyd, R N; Famiano, M A; Meyer, B S; Motizuki, Y; Kajino, T; Roederer, I U

    2011-11-30

    Nucleosynthesis of heavy nuclei in metal-poor stars is generally ascribed to the r-process, as the abundance pattern in many such stars agrees with the inferred Solar r-process abundances. Nonetheless, a significant number of these stars do not share this r-process template. they suggest that many such stars have begun an r-process, but it was prevented from running to completion in more massive stars by collapse to black holes, creating a 'truncated r-process,' or 'tr-process'. The observed fraction of tr-process stars is found to be consistent with expectations from the initial mass function (IMF), and they suggest that an apparent sharp truncation observed at around mass 160 could result from a combination of collapses to black holes and the difficulty of observing the higher mass rare earths. They test the tr-process hypothesis with calculations that are terminated before all r-process trajectories have been ejected. These produce qualitative agreement with observation when both black hole collapse and observational realities are taken into account.

  13. The fundamental role of fission during r-process nucleosynthesis in neutron star mergers

    NASA Astrophysics Data System (ADS)

    Goriely, S.

    2015-02-01

    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. Despite important efforts, the astrophysical site of the r-process remains unidentified. Here we study r-process nucleosynthesis in a material that is dynamically ejected by tidal and pressure forces during the merging of binary neutron stars. r-process nucleosynthesis during the decompression is known to be largely insensitive to the detailed astrophysical conditions because of efficient fission recycling, producing a composition that closely follows the solar r-abundance distribution for nuclei with mass numbers A > 140. Due to the important role played by fission in such a scenario, the impact of fission is carefully analyzed. We consider different state-of-the-art global models for the determination of the fission paths, nuclear level densities at the fission saddle points and fission fragment distributions. Based on such models, the sensitivity of the calculated r-process abundance distribution is studied. The fission path is found to strongly affect the region of heavy nuclei responsible for the fission recycling, while the fission fragment distribution of nuclei along the A ? 278 isobars defines the abundance pattern of nuclei produced in the 110 ? A ? 170 region. The late capture of prompt fission neutrons is also shown to affect the abundance distribution, and in particular the shape of the third r-process peak around A ? 195.

  14. R-Process in Neutron Star Merger with a New Fission Model

    NASA Astrophysics Data System (ADS)

    Shibagaki, Shota; Kajino, Toshitaka; Mathews, Grant J.; Chiba, Satoshi

    Neutron star mergers (NSMs) are one of the candidates for the r-process production site. Because the ejected matter from the NSMs is extremely neutron-rich, the nuclear fission play a essential role in the r-process. In this study we carry out r-process nucleosynthesis simulations of a neutron star merger. We here constructed a nuclear reaction network code by setting the new nuclear mass model and the new fission fragment distribution model. Our nucleosynthesis simulation then shows that the final r-process elemental abundances exhibit very flat pattern for A = 90-180, and several fission cycling operates in extremely neutron-rich conditions of the NSMs. We also derive an analytic formula to evaluate the number of fission cycle and compare it with our numerical results. Combining these results with magneto- hydrodynamic jet models for core-collapse supernovae (CCSNe) that predict successful r-process abundance peaks at A ˜ 130 and 195,we find that the NSMs can resolve the underproduction problems of such CCSN model prediction for the elements just below and above the abundance peaks. We discuss relative contributions to the solar-system r-process yields from CCSNe and NSMs, which should constrain the frequency of these astrophysical episodes that can produce r-process elements in very different manner and abundance pattern.

  15. Roles of fission, Neutron Star Mergers and Supernovae in R-Process Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Shibagaki, Shota; Kajino, Toshitaka; Chiba, Satoshi; Mathews, Grant

    2014-09-01

    The astrophysical site for the r-process has not yet been uniquely identified. Neutron star mergers (NSMs) have recently received special attention as production sites for the r-process. The ejected matter from the NSMs is extremely neutron-rich (Ye < 0.1) and the r-process path proceeds along the neutron drip line and enters the region of fissile nuclei. In this situation, theoretical models of nuclear masses and fission are important. In this study, we carry out r-process nucleosynthesis simulations in the NSMs. We constructed a nuclear reaction network code by setting new models of nuclear masses and fission. Our result shows that the final r-process elemental abundances exhibit flat pattern for A = 90--180 due to several fission cycling in extremely neutron-rich conditions of the NSMs. Combining these results with magnetorotaionally driven core-collapse supernovae (CCSNe) that predict successful r-process abundance peaks at A ~ 130 and 195, we find that the NSMs can resolve the underproduction problems of such CCSN model prediction for the elements just below and above the abundance peaks. We discuss relative contribution to the solar-system r-process yields from CCSNe and NSMs.

  16. Energy Conservation R. D. & D. Programs in High Temperature Processes 

    E-print Network

    Sheneman, R. L.

    1979-01-01

    . The blast furnace supported by the coke oven for its operation represents r very large investment, fuel or coke is a large share of the total cost of the operation and this daily throughput is quite large ranging from 2000 tons to 7000 tons of hot metal... in advancing the state of the art. Huge furnaqes : 45 feet in diameter have become the new standard and charging and agglomeratio~ ! have been carefully reoptimized resulting in significant reduction of coke to ~ron j ratio. Large research budgets...

  17. Relative contributions of the weak, main and fission-recycling r-process

    E-print Network

    S. Shibagaki; T. Kajino; G. J. Mathews; S. Chiba; S. Nishimura; G. Lorusso

    2015-12-26

    There has been a persistent conundrum in attempts to model the nucleosynthesis of heavy elements by rapid neutron capture (the $r$-process). Although the location of the abundance peaks near nuclear mass numbers 130 and 195 identify an environment of rapid neutron capture near closed nuclear shells, the abundances of elements just above and below those peaks are often underproduced by more than an order of magnitude in model calculations. At the same time there is a debate in the literature as to what degree the $r$-process elements are produced in supernovae or the mergers of binary neutron stars. In this paper we propose a novel solution to both problems. We demonstrate that the underproduction of elements above and below the $r$-process peaks characteristic in the main or weak $r$-process events (like magnetohydrodynamic jets or neutrino-driven winds in core-collapse supernovae) can be supplemented via fission fragment distributions from the recycling of material in a neutron-rich environment such as that encountered in neutron star mergers. In this paradigm, the abundance peaks themselves are well reproduced by a moderately neutron rich, main $r$-process environment such as that encountered in the magnetohydrodynamical jets in supernovae supplemented with a high-entropy, weakly neutron rich environment such as that encountered in the neutrino-driven-wind model to produce the lighter $r$-process isotopes. Moreover, we show that the relative contributions to the $r$-process abundances in both the solar-system and metal-poor stars from the weak, main, and fission-recycling environments required by this proposal are consistent with estimates of the relative Galactic event rates of core-collapse supernovae for the weak and main $r$-process and neutron star mergers for the fission-recycling $r$-process.

  18. Relative contributions of the weak, main and fission-recycling r-process

    E-print Network

    S. Shibagaki; T. Kajino; G. J. Mathews; S. Chiba; S. Nishimura; G. Lorusso

    2015-05-09

    There has been a persistent conundrum in attempts to model the nucleosynthesis of heavy elements by rapid neutron capture (the $r$-process). Although the location of the abundance peaks near nuclear mass numbers 130 and 195 identify an environment of rapid neutron capture near closed nuclear shells, the abundances of elements just above and below those peaks are often underproduced by more than an order of magnitude in model calculations. At the same time there is a debate in the literature as to what degree the $r$-process elements are produced in supernovae or the mergers of binary neutron stars. In this paper we propose a novel solution to both problems. We demonstrate that the underproduction of elements above and below the $r$-process peaks characteristic in the main or weak $r$-process events (like magnetohydrodynamic jets or neutrino-driven winds in core-collapse supernovae) can be supplemented via fission fragment distributions from the recycling of material in a neutron-rich environment such as that encountered in neutron star mergers. In this paradigm, the abundance peaks themselves are well reproduced by a moderately neutron rich, main $r$-process environment such as that encountered in the magnetohydrodynamical jets in supernovae supplemented with a high-entropy, weakly neutron rich environment such as that encountered in the neutrino-driven-wind model to produce the lighter $r$-process isotopes. Moreover, we show that the relative contributions to the $r$-process abundances in both the solar-system and metal-poor stars from the weak, main, and fission-recycling environments required by this proposal are consistent with estimates of the relative Galactic event rates of core-collapse supernovae for the weak and main $r$-process and neutron star mergers for the fission-recycling $r$-process.

  19. r-Process Nucleosynthesis in Shocked Surface Layers of O-Ne-Mg Cores

    E-print Network

    H. Ning; Y. -Z. Qian; B. S. Meyer

    2007-08-13

    We demonstrate that rapid expansion of the shocked surface layers of an O-Ne-Mg core following its collapse can result in r-process nucleosynthesis. As the supernova shock accelerates through these layers, it makes them expand so rapidly that free nucleons remain in disequilibrium with alpha-particles throughout most of the expansion. This allows heavy r-process isotopes including the actinides to form in spite of the very low initial neutron excess of the matter. We estimate that yields of heavy r-process nuclei from this site may be sufficient to explain the Galactic inventory of these isotopes.

  20. Study of the Element Abundances in HD 140283: The Abundance Robustness of the Weak r- and Main r-Process Stars

    NASA Astrophysics Data System (ADS)

    Niu, Ping; Cui, Wenyuan; Zhang, Bo

    2015-11-01

    Many works have attempted to investigate the astrophysical origin of the neutron-capture elements in the metal-poor star HD 140283. However, no definite conclusions have been drawn. In this work, using the abundance-decomposed approach, we find that the metal-poor star HD 140283 is a weak r-process star. Although this star is a weak r-process star, its Ba abundance mainly originates from the main r-process. This is the reason that the ratio [Ba/Eu]=\\-0.58+/- 0.15 for HD 140283 is close to the ratio of the main r-process. Based on the comparison of the abundances in the six-weak r-process stars, we find that their element abundances possess a robust nature. On the other hand, we find that the robust nature of the abundance of the extreme main r-process stars ([r/Fe] ?slant 1.5) can be extended to the lighter neutron-capture elements. Furthermore, the abundance characteristics of the weak r-process and main r-process are investigated. The abundance robustness of the two category r-process stars could be used as the constraint of the r-process theory and could be used to investigate the astrophysical origins of the elements in the metal-poor stars and population I stars.

  1. Theoretical analysis of channel drop tunneling processes Shanhui Fan, Pierre R. Villeneuve, and J. D. Joannopoulos

    E-print Network

    Fan, Shanhui

    Theoretical analysis of channel drop tunneling processes Shanhui Fan, Pierre R. Villeneuve, and J, Massachusetts 02139 Received 30 November 1998 We investigate general channel drop tunneling processes using both and electronic devices. Channel drop tunneling processes, in particular, have captured recent interest, due

  2. The Astrophysical r-Process 50 Years after B{sup 2}FH

    SciTech Connect

    Kratz, K.-L.; Pfeiffer, B.; Farouqi, K.; Mashonkina, L. I.

    2008-01-24

    Since the historical papers by Burbidge et al. and Cameron 50 years ago, it is generally accepted that half of the chemical elements above Fe are formed in explosive stellar scenarios by a rapid neutron-capture process (the classical ''r-process''). Already from their essential ideas, it became clear that a correct modelling of this nucleosynthesis process requires both, the knowledge of various nuclear properties very far from stability and a detailed description of the astrophysical environments. However, it took about three decades, until in 1986 the first experimental nuclear-physics data on the neutron-magic r-isotopes {sup 80}Zn and {sup 130}Cd could be obtained, which act as key ''waiting points'' in the respective A{approx_equal}80 and 130 peaks of the Solar-System (SS) r-abundances (N{sub r,{center_dot}}). Since then, using steadily improved nuclear data, we have optimized our r-process calculations to reproduce the present observables of the isotopic N{sub r,{center_dot}} ''residuals'', as well as the more recent elemental abundances in ultra-metal-poor, r-process-enriched halo stars. Concerning the latter observations, we support the basic idea about two different types of r-processes. Based on our many years' experience with the site-independent ''waiting-point approach'', we recently have extended our studies to fully dynamical network calculations for the most likely astrophysical r-process scenario, i.e. the high-entropy wind (HEW) of core-collapse type II supernovae (SN II). Again, an excellent reproduction of all observables for the ''main'' r-process has been achieved. However, a major difference is the nucleosynthesis origin of the lighter heavy elements in the 29{<=}Z{<=}45 mass region. Here, the HEW model predicts-instead of a ''weak'' neutron-capture r-process component-a primary rapid charged-particle process. This may explain the recent observations of a non-correlation of these elements with the heavier ''main'' r-process elements.

  3. PRE-PROCESSING MASS SPECTROMETRY Kevin R. Coombes

    E-print Network

    Morris, Jeffrey S.

    . Morris Department of Biostatistics and Applied Mathematics University of Texas M.D. Anderson Cancer, urine, or nipple aspirate fluid [Paweletz et al., 2001; Wellmann et al., 2002; Pet- ricoin et al., 2002 it to the proteins causing them to desorb and ionize, and pro- duce a plume of ions in the gas phase. This process

  4. The Hamburg/ESO R-process enhanced star survey (HERES). V. Detailed abundance analysis of the r-process enhanced star HE 2327-5642

    NASA Astrophysics Data System (ADS)

    Mashonkina, L.; Christlieb, N.; Barklem, P. S.; Hill, V.; Beers, T. C.; Velichko, A.

    2010-06-01

    Aims: We present a detailed abundance analysis of a strongly r-process enhanced giant star discovered in the HERES project, HE 2327-5642, for which [Fe/H] = -2.78, [r/Fe] = +0.99. Methods: We determined the stellar parameters and element abundances by analyzing the high-quality VLT/UVES spectra. The surface gravity was calculated from the non-local thermodynamic equilibrium (NLTE) ionization balance between ion{Fe}{i} and ion{Fe}{ii}, and ion{Ca}{i} and ion{Ca}{ii}. Results: Accurate abundances for a total of 40 elements and for 23 neutron-capture elements beyond Sr and up to Th were determined in HE 2327-5642. For every chemical species, the dispersion in the single line measurements around the mean does not exceed 0.11 dex. The heavy element abundance pattern of HE 2327-5642 is in excellent agreement with those previously derived for other strongly r-process enhanced stars, such as CS 22892-052, CS 31082-001, and HE 1219-0312. Elements in the range from Ba to Hf match the scaled Solar r-process pattern very well. No firm conclusion can be drawn about the relationship between the fisrt neutron-capture peak elements, Sr to Pd, in HE 2327-5642 and the Solar r-process, due to the uncertainty in the Solar r-process. A clear distinction in Sr/Eu abundance ratios was found between the halo stars of different europium enhancement. The strongly r-process enhanced stars contain a low Sr/Eu abundance ratio at [Sr/Eu] = -0.92 ± 0.13, while the stars with 0 < [Eu/Fe] < 1 and [Eu/Fe] < 0 have 0.36 dex and 0.93 dex higher Sr/Eu values, respectively. Radioactive dating for HE 2327-5642 with the observed thorium and rare-earth element abundance pairs results in an average age of 13.3 Gyr, when based on the high-entropy wind calculations, and 5.9 Gyr, when using the Solar r-residuals. We propose that HE 2327-5642 is a radial-velocity variable based on our high-resolution spectra covering 4.3 years. Based on observations collected at the European Southern Observatory, Paranal, Chile (Proposal numbers 170.D-0010, and 280.D-5011).Table 8 is only available in electronic form at http://www.aanda.org

  5. Process Systems Engineering R&D for Advanced Fossil Energy Systems

    SciTech Connect

    Zitney, S.E.

    2007-09-11

    This presentation will examine process systems engineering R&D needs for application to advanced fossil energy (FE) systems and highlight ongoing research activities at the National Energy Technology Laboratory (NETL) under the auspices of a recently launched Collaboratory for Process & Dynamic Systems Research. The three current technology focus areas include: 1) High-fidelity systems with NETL's award-winning Advanced Process Engineering Co-Simulator (APECS) technology for integrating process simulation with computational fluid dynamics (CFD) and virtual engineering concepts, 2) Dynamic systems with R&D on plant-wide IGCC dynamic simulation, control, and real-time training applications, and 3) Systems optimization including large-scale process optimization, stochastic simulation for risk/uncertainty analysis, and cost estimation. Continued R&D aimed at these and other key process systems engineering models, methods, and tools will accelerate the development of advanced gasification-based FE systems and produce increasingly valuable outcomes for DOE and the Nation.

  6. Physical processes and hypoxia in the central basin of Lake Erie Yerubandi R. Rao1

    E-print Network

    of the Great Lakes basin resides within the Lake Erie watershed, so of all of the Great Lakes, Lake EriePhysical processes and hypoxia in the central basin of Lake Erie Yerubandi R. Rao1 Environment, Burlington, Ontario L7R 4A6, Canada Nathan Hawley NOAA­Great Lakes Environmental Research Laboratory, 2205

  7. The Hamburg/ESO R-process Enhanced Star survey (HERES). X. HE 2252-4225, one more r-process enhanced and actinide-boost halo star

    NASA Astrophysics Data System (ADS)

    Mashonkina, L.; Christlieb, N.; Eriksson, K.

    2014-09-01

    Context. Studies of the r-process enhanced stars are important for understanding the nature and origin of the r-process better. Aims: We present a detailed abundance analysis of a very metal-poor giant star discovered in the HERES project, HE 2252-4225, which exhibits overabundances of the r-process elements with [r/Fe] = +0.80. Methods: We determined the stellar atmosphere parameters, Teff = 4710 K, log g = 1.65, and [ Fe/H ] = -2.63, and chemical abundances by analysing the high-quality VLT/UVES spectra. The surface gravity was calculated from the non-local thermodynamic equilibrium (NLTE) ionisation balance between Fe i and Fe ii. Results: Accurate abundances for a total of 38 elements, including 22 neutron-capture elements beyond Sr and up to Th, were determined in HE 2252-4225. For every chemical species, the dispersion in the single line measurements around the mean does not exceed 0.12 dex. This object is deficient in carbon, as expected for a giant star with Teff < 4800 K. The stellar Na-Zn abundances are well fitted by the yields of a single supernova of 14.4 M?. For the neutron-capture elements in the Sr-Ru, Ba-Yb, and Os-Ir regions, the abundance pattern of HE 2252-4225 is in excellent agreement with the average abundance pattern of the strongly r-process enhanced stars CS 22892-052, CS 31082-001, HE 1219-0312, and HE 1523-091. This suggests a common origin of the first, second, and third r-process peak elements in HE 2252-4225 in the classical r-process. We tested the solar r-process pattern based on the most recent s-process calculations of Bisterzo, Travaglio, Gallino, Wiescher, and Käppeler and found that elements in the range from Ba to Ir match it very well. No firm conclusion can be drawn about the relationship between the first neutron-capture peak elements, Sr to Ru, in HE 2252-4225 and the solar r-process, owing to the uncertainty in the solar r-process. The investigated star has an anomalously high Th/Eu abundance ratio, so that radioactive dating results in a stellar age of ? = 1.5 ± 1.5 Gyr that is not expected for a very metal-poor halo star. Based on observations collected at the European Southern Observatory, Paranal, Chile (Proposal numbers 170.D-0010, and 280.D-5011).Table 3 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/569/A43

  8. r-process in Type II supernovae and the role of direct capture

    SciTech Connect

    Otsuki, K.; Burrows, A.; Martinez-Pinedo, G.; Typel, S.; Langanke, K.; Matos, M.

    2010-06-01

    We have calculated r-process nucleosynthesis based on acoustic wave driven supernova simulation. The environment includes extremely high entropy cases which has not been studied in previous studies. Plenty of actinide and third peak elements are formed in an averaged abundance, while elements around the first and second peaks are overproduced. We also studied the effect of direct capture in r-process. The direct capture furthers r-process and make freeze out earlier. It will change the final abundance drastically. We recalculated r-process nucleosynthesis of the simulation considering the direct capture reaction. While we could not see a significant difference in averaged abundances, significant differences appeared in several individual yields.

  9. The Sensitivity of r-PROCESS Nucleosynthesis to the Properties of Neutron-Rich Nuclei

    NASA Astrophysics Data System (ADS)

    Surman, R.; Mumpower, M. R.; Cass, J.; Aprahamian, A.

    2014-09-01

    About half of the heavy elements in the Solar System were created by rapid neutron capture, or r-process, nucleosynthesis. In the r-process, heavy elements are built up via a sequence of neutron captures and beta decays in which an intense neutron flux pushes material out towards the neutron drip line. The nuclear network simulations used to test potential astrophysical scenarios for the r-process therefore require nuclear physics data (masses, beta decay lifetimes, neutron capture rates, fission probabilities) for thousands of nuclei far from stability. Only a small fraction of this data has been experimentally measured. Here we discuss recent sensitivity studies that aim to determine the nuclei whose properties are most crucial for r-process calculations.

  10. Detection of the Second R-Process Peak Element Tellurium in Metal-Poor Stars

    E-print Network

    Roederer, Ian U.

    Using near-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, we detect neutral tellurium in three metal-poor stars enriched by products of r-process nucleosynthesis, ...

  11. r-process nucleosynthesis in the high-entropy supernova bubble

    NASA Technical Reports Server (NTRS)

    Meyer, B. S.; Mathews, G. J.; Howard, W. M.; Woosley, S. E.; Hoffman, R. D.

    1992-01-01

    We show that the high-temperature, high-entropy evacuated region outside the recent neutron star in a core-collapse supernova may be an ideal r-process site. In this high-entropy environment it is possible that most nucleons are in the form of free neutrons or bound into alpha particles. Thus, there can be many neutrons per seed nucleus even though the material is not particularly neutron rich. The predicted amount of r-process material ejected per event from this environment agrees well with that required by simple galactic evolution arguments. When averaged over regions of different neutron excess in the supernova ejecta, the calculated r-process abundance curve can give a good representation of the solar-system r-process abundances as long as the entropy per baryon is sufficiently high. Neutrino irradiation may aid in smoothing the final abundance distribution.

  12. Web Text Corpus for Natural Language Processing Vinci Liu and James R. Curran

    E-print Network

    Curran, James R.

    Web Text Corpus for Natural Language Processing Vinci Liu and James R. Curran School of Information Technologies University of Sydney NSW 2006, Australia {vinci,james}@it.usyd.edu.au Abstract Web text has been

  13. Light-Element Reaction Flow and the Conditions for r-Process Nucleosynthesis

    E-print Network

    T. Sasaqui; K. Otsuki; T. Kajino; G. J. Mathews

    2006-03-18

    We deduce new constraints on the entropy per baryon ($s/k$), dynamical timescale ($\\tau_{dyn}$), and electron fraction ($Y_{e}$) consistent with heavy element nucleosynthesis in the r-process. We show that the previously neglected reaction flow throu gh the reaction sequence \\atg (n,$\\gamma$)\\Li~ significantly enhances the production of seed nuclei. We analyze the r-process nucleosynthesis in the context of a schematic exponential wi nd model. We show that fewer neutrons per seed nucleus implies that the entropy per baryon required for successful r-process nucleosynthesis must be more than a factor of two higher than previous estimates. This places new constraints on dynamical mo dels for the r-process.

  14. The search for the site of the r-process. [rapid neutron capture in stellar nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Cowan, John J.; Cameron, A. G. W.; Truran, J. W.; Sneden, Christopher

    1986-01-01

    A number of sites have been suggested for the r-process, including neutronized cores of exploding supernovae, jets of neutronized matter ejected from the collapse of rotating magnetized stellar cores, the helium and carbon zones of stars undergoing supernova explosions, and helium core flashes in low-mass stars. Despite much work and many advances in nuclear physics, the site or sites of the r-process is still unknown. Observations of metal-poor stars in the halo of the Galaxy indicate r-process production early in the history of the Galaxy and provide important constraints on galactic nucleosynthesis. Further observations of metal-poor stars, along with advances in understanding the nuclear properties of neutron-rich nuclei and improved astrophysical models of stars in the late stages of evolution, should help to identify the site of the r-process.

  15. The sensitivity of r-process nucleosynthesis to the properties of neutron-rich nuclei

    E-print Network

    R. Surman; M. Mumpower; J. Cass; A. Aprahamian

    2013-08-31

    About half of the heavy elements in the Solar System were created by rapid neutron capture, or r-process, nucleosynthesis. In the r-process, heavy elements are built up via a sequence of neutron captures and beta decays in which an intense neutron flux pushes material out towards the neutron drip line. The nuclear network simulations used to test potential astrophysical scenarios for the r-process therefore require nuclear physics data (masses, beta decay lifetimes, neutron capture rates, fission probabilities) for thousands of nuclei far from stability. Only a small fraction of this data has been experimentally measured. Here we discuss recent sensitivity studies that aim to determine the nuclei whose properties are most crucial for r-process calculations.

  16. NEW ABUNDANCE DETERMINATIONS OF CADMIUM, LUTETIUM, AND OSMIUM IN THE r-PROCESS ENRICHED STAR BD +17 3248

    E-print Network

    Cowan, John

    NEW ABUNDANCE DETERMINATIONS OF CADMIUM, LUTETIUM, AND OSMIUM IN THE r-PROCESS ENRICHED STAR BD +17 ABUNDANCE DETERMINATIONS OF CADMIUM, LUTETIUM, AND OSMIUM IN THE r-PROCESS ENRICHED STAR BD +17 3248, Ian U

  17. Processing of R-Ba-Cu-O superconductors

    SciTech Connect

    Wu, H.

    1998-02-23

    Precipitation processes were developed to introduce second phases as flux pinning centers in Gd-Ba-Cu-O and Nd-Ba-Cu-O superconductors. In Gd-Ba-Cu-O, precipitation is caused by the decrease of the upper solubility limit of Gd{sub 1+x}Ba{sub 2{minus}x}Cu{sub 3}O{sub 7} solid solution (Gd123ss) in low oxygen partial pressure. Processing of supersaturated Gd{sub 1.2}Ba{sub 1.8}Cu{sub 3}O{sub 7} in low oxygen partial pressure can produce dispersed second phases. Gd211 is formed as a separate phase while extensive Gd124 type stacking fault is formed instead of a separate CuO phase. As a result of the precipitation reaction, the transition temperature and critical current density are increased. In Nd-Ba-Cu-O, precipitation is caused by the decrease of the lower solubility limit of Nd{sub 1+x}Ba{sub 2{minus}x}Cu{sub 3}O{sub 7} solid solution (Nd123ss) in oxygen. DTA results reveal the relative stability of Nd123ss in different oxygen partial pressures. In 1 bar oxygen partial pressure, Nd123ss with x = 0.1 is the most stable phase. In lower oxygen partial pressures, the most stable composition shifts towards the stoichiometric composition. The relative stability changes faster with decreasing oxygen partial pressure. Therefore, processing in oxygen and air tends to produce broad superconducting transitions but sharp transitions can be achieved in 0.01 bar and 0.001 bar oxygen partial pressures. While the lower solubility limits in 0.01 bar and 0.001 bar oxygen partial pressures remain at x = 0.00, the solubility limits in oxygen and air show a narrowing with decreasing temperature. Because of the narrowing of the solubility range in oxygen, oxygen annealing of Nd123 initially processed in low oxygen partial pressures will result in precipitation of second phases. The equilibrium second phase is BaCuO{sub 2} for temperature above 608 C, and at lower temperatures the equilibrium second phases are Ba{sub 2}CuO{sub 3.3} and Ba{sub 2}Cu{sub 3}O{sub 5+y}. However, annealing at low temperature may produce a fine metastable transition phase. A coherent intermediate perovskite structure with a composition of BaCuO{sub 2} is observed along with a high density of dislocations during the precipitation process at 500 C in oxygen. It is believed that oxygen annealing at 900 C produces the equilibrium BaCuO{sub 2} phase. These precipitates are responsible for the strong flux pinning in Nd123 melt-textured in low oxygen partial pressure.

  18. Study of the element abundances in HD 140283: the abundance robustness of the weak r- and main r-process stars

    E-print Network

    Niu, Ping; Zhang, Bo

    2015-01-01

    Many works have attempted to investigate the astrophysical origin of the neutron-capture elements in the metalpoor star HD 140283. However, no definite conclusions have been drawn. In this work, using the abundancedecomposed approach, we find that the metal-poor star HD 140283 is a weak r-process star. Although this star is a weak r-process star, its Ba abundance mainly originates from the main r-process. This is the reason that the ratio [Ba/Eu]= -0.58+- 0.15 for HD 140283 is close to the ratio of the main r-process. Based on the comparison of the abundances in the six-weak r-process stars, we find that their element abundances possess a robust nature. On the other hand, we find that the robust nature of the abundance of the extreme main r-process stars ([r/Fe]>= 1.5) can be extended to the lighter neutron-capture elements. Furthermore, the abundance characteristics of the weak r-process and main r-process are investigated. The abundance robustness of the two category r-process stars could be used as the con...

  19. The r-Process in Supernovae: Impact of New Microscopic Mass Formulas

    E-print Network

    Shinya Wanajo; Stephane Goriely; Mathieu Samyn; Naoki Itoh

    2004-01-21

    The astrophysical origin of $r$-process nuclei remains a long-standing mystery. Although some astrophysical scenarios show some promise, many uncertainties involved in both the astrophysical conditions and in the nuclear properties far from the $\\beta$-stability have inhibited us from understanding the nature of the $r$-process. The purpose of the present paper is to examine the effects of the newly-derived microscopic Hartree-Fock-Bogoliubov (HFB) mass formulas on the $r$-process nucleosynthesis and analyse to what extent a solar-like $r$-abundance distribution can be obtained. The $r$-process calculations with the HFB-2 mass formula are performed, adopting the parametrized model of the prompt explosion from a collapsing O-Ne-Mg core for the physical conditions and compared with the results obtained with the HFB-7 and droplet-type mass formulas. Due to its weak shell effect at the neutron magic numbers in the neutron-rich region, the microscopic mass formulas (HFB-2 and HFB-7) give rise to a spread of the abundance distribution in the vicinity of the $r$-process peaks ($A = 130$ and 195). While this effect resolves the large underproduction at $A \\approx 115$ and 140 obtained with droplet-type mass formulas, large deviations compared to the solar pattern are found near the third $r$-process peak. It is shown that a solar-like $r$-process pattern can be obtained if the dynamical timescales of the outgoing mass trajectories are increased by a factor of about 2-3, or if the $\\beta$-decay rates are systematically increased by the same factor.

  20. Enrichment of r-process elements in dwarf spheroidal galaxies in chemo-dynamical evolution model

    E-print Network

    Hirai, Yutaka; Saitoh, Takayuki R; Fujii, Michiko S; Hidaka, Jun; Kajino, Toshitaka

    2015-01-01

    The rapid neutron-capture process (r-process) is a major process to synthesize elements heavier than iron, but the astrophysical site(s) of r-process is not identified yet. Neutron star mergers (NSMs) are suggested to be a major r-process site from nucleosynthesis studies. Previous chemical evolution studies however require unlikely short merger time of NSMs to reproduce the observed large star-to-star scatters in the abundance ratios of r-process elements relative to iron, [Eu/Fe], of extremely metal-poor stars in the Milky Way (MW) halo. This problem can be solved by considering chemical evolution in dwarf spheroidal galaxies (dSphs) which would be building blocks of the MW and have lower star formation efficiencies than the MW halo. We demonstrate that enrichment of r-process elements in dSphs by NSMs using an N-body/smoothed particle hydrodynamics code. Our high-resolution model reproduces the observed [Eu/Fe] by NSMs with a merger time of 100 Myr when the effect of metal mixing is taken into account. Thi...

  1. PRODUCTION OF ALL THE r-PROCESS NUCLIDES IN THE DYNAMICAL EJECTA OF NEUTRON STAR MERGERS

    SciTech Connect

    Wanajo, Shinya; Sekiguchi, Yuichiro; Kiuchi, Kenta; Shibata, Masaru; Nishimura, Nobuya; Kyutoku, Koutarou

    2014-07-10

    Recent studies suggest that binary neutron star (NS-NS) mergers robustly produce heavy r-process nuclei above the atomic mass number A ? 130 because their ejecta consist of almost pure neutrons (electron fraction of Y {sub e} < 0.1). However, the production of a small amount of the lighter r-process nuclei (A ? 90-120) conflicts with the spectroscopic results of r-process-enhanced Galactic halo stars. We present, for the first time, the result of nucleosynthesis calculations based on the fully general relativistic simulation of a NS-NS merger with approximate neutrino transport. It is found that the bulk of the dynamical ejecta are appreciably shock-heated and neutrino processed, resulting in a wide range of Y {sub e} (?0.09-0.45). The mass-averaged abundance distribution of calculated nucleosynthesis yields is in reasonable agreement with the full-mass range (A ? 90-240) of the solar r-process curve. This implies, if our model is representative of such events, that the dynamical ejecta of NS-NS mergers could be the origin of the Galactic r-process nuclei. Our result also shows that radioactive heating after ?1 day from the merging, which gives rise to r-process-powered transient emission, is dominated by the ?-decays of several species close to stability with precisely measured half-lives. This implies that the total radioactive heating rate for such an event can be well constrained within about a factor of two if the ejected material has a solar-like r-process pattern.

  2. Microbiological processes in banded iron formation deposition NICOLE R. POSTH*1

    E-print Network

    Konhauser, Kurt

    Microbiological processes in banded iron formation deposition NICOLE R. POSTH*1 , KURT O. KONHAUSER reconstructions. Herein, the current theories of microbial processes in banded iron formation mineral deposition be used as proxies for the emergence of oxygen, from its initial production in the oceans by at least 2Á7

  3. The r-process nucleosynthesis during the decompression of neutron star crust material

    SciTech Connect

    Goriely, S.; Bauswein, A.; Janka, H.-T.; Sida, J.-L.; Lemaître, J.-F.; Panebianco, S.

    2014-05-02

    About half of the nuclei heavier than iron observed in nature are produced by the so-called 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, for which essentially no experimental data exist. The present paper 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. Both the astrophysics and the nuclear physics difficulties are critically reviewed with special attention paid to the r-process taking place during the decompression of neutron star matter following the merging of two neutron stars.

  4. Isotopic compositions of bismuth, lead, thallium, and mercury from mini r-processing

    NASA Technical Reports Server (NTRS)

    Heymann, D.; Liffman, K.

    1986-01-01

    The yields of stable isotopes of Bi, Pb, Tl and Hg as well as yields of Pb-205 are calculated with a parametrized model for 'mini r-processing' in the Ne, O, C-rich zones of explosive burning in massive stars. The Pb isotopic compositions stand out by their comparatively low Pb-207 yields and by the fact that this r-process variant yields Pb-204 quite abundantly. The average Pb-205/Pb-204 yield ratio of 6.1 is the same order of magnitude as yield ratios deduced for s-processing. The Hg from this mini r-process looks like normal solar-system mercury, but with Hg-196 missing and the light s-isotopes A = 198, 199, 200 and 201 depleted (especially the odd-A species).

  5. The impact of individual nuclear properties on $r$-process nucleosynthesis

    E-print Network

    Mumpower, M R; McLaughlin, G C; Aprahamian, A

    2015-01-01

    The astrophysical rapid neutron capture process or `$r$ process' of nucleosynthesis is believed to be responsible for the production of approximately half the heavy element abundances found in nature. This multifaceted problem remains one of the greatest open challenges in all of physics. Knowledge of nuclear physics properties such as masses, $\\beta$-decay and neutron capture rates, as well as $\\beta$-delayed neutron emission probabilities are critical inputs that go into calculations of $r$-process nucleosynthesis. While properties of nuclei near stability have been established, much still remains unknown regarding neutron-rich nuclei far from stability that may participate in the $r$ process. Sensitivity studies gauge the astrophysical response of a change in nuclear physics input(s) which allows for the isolation of the most important nuclear properties that shape the final abundances observed in nature. This review summarizes the extent of recent sensitivity studies and highlights how these studies play ...

  6. Enrichment of r-process Elements in Dwarf Spheroidal Galaxies in Chemo-dynamical Evolution Model

    NASA Astrophysics Data System (ADS)

    Hirai, Yutaka; Ishimaru, Yuhri; Saitoh, Takayuki R.; Fujii, Michiko S.; Hidaka, Jun; Kajino, Toshitaka

    2015-11-01

    The rapid neutron-capture process (r-process) is a major process for the synthesis of elements heavier than iron-peak elements, but the astrophysical site(s) of the r-process has not yet been identified. Neutron star mergers (NSMs) are suggested to be a major r-process site according to nucleosynthesis studies. Previous chemical evolution studies, however, required unlikely short merger times of NSMs to reproduce the observed large star-to-star scatters in the abundance ratios of r-process elements to iron: the [Eu/Fe] of extremely metal-poor stars in the Milky Way (MW) halo. This problem can be solved by considering chemical evolution in dwarf spheroidal galaxies (dSphs), which would be building blocks of the MW and have lower star formation efficiencies than the MW halo. We demonstrate the enrichment of r-process elements in dSphs by NSMs using an N-body/smoothed particle hydrodynamics code. Our high-resolution model reproduces the observed [Eu/Fe] due to NSMs with a merger time of 100 Myr when the effect of metal mixing is taken into account. This is because metallicity is not correlated with time ?300 Myr from the start of the simulation due to the low star formation efficiency in dSphs. We also confirm that this model is consistent with observed properties of dSphs such as radial profiles and metallicity distribution. The merger time and the Galactic rate of NSMs are suggested to be ?300 Myr and ?10?4 year?1, respectively, which are consistent with the values suggested by population synthesis and nucleosynthesis studies. This study supports the argument that NSMs are the major astrophysical site of the r-process.

  7. Strength of nuclear shell effects at N=126 in the r-process region

    SciTech Connect

    Farhan, A.R.; Sharma, M.M.

    2006-04-15

    We have investigated nuclear-shell effects across the magic number N=126 in the region of the r-process path. Microscopic calculations have been performed using the relativistic Hartree-Bogoliubov approach within the framework of the relativistic mean-field (RMF) theory for isotopic chains of rare-earth nuclei in the r-process region. The Lagrangian model NL-SV1 with the inclusion of the vector self-coupling of {omega} meson has been employed. The RMF results show that the shell effects at N=126 remain strong and exhibit only a slight reduction in the strength in going from the r-process path to the neutron drip line. This is in striking contrast to a systematic weakening of the shell effects at N=82 in the r-process region predicted earlier in the similar approach. In comparison the shell effects with microscopic-macroscopic mass formulas show a near constancy of shell gaps leading to strong shell effects in the region of r-process path to the drip line. A recent analysis of solar-system r-process abundances in a prompt supernova explosion model using various mass formulas, including the recently introduced mass tables based on Hartree-Fock-Bogoliubov method shows that although mass formulas with weak shell effects at N=126 give rise to a spread and an overproduction of nuclides near the third abundance peak at A{approx}190, mass tables with droplet models showing stronger shell effects are able to reproduce the abundance features near the third peak appropriately. In comparison, several analyses of the second r-process peak at A{approx}130 have required weakened (quenched) shell effects at N=82. Our predictions in the RMF theory with NL-SV1, which exhibit weaker shell effects at N=82 and correspondingly stronger shell effects at N=126 in the r-process region, support the conjecture that a different nature of the shell effects at the magic numbers may be at play in r-process nucleosynthesis of heavy nuclei.

  8. Nuclear robustness of the r process in neutron-star mergers

    NASA Astrophysics Data System (ADS)

    Mendoza-Temis, Joel de Jesús; Wu, Meng-Ru; Langanke, Karlheinz; Martínez-Pinedo, Gabriel; Bauswein, Andreas; Janka, Hans-Thomas

    2015-11-01

    We have performed r -process calculations for matter ejected dynamically in neutron star mergers based on a complete set of trajectories from a three-dimensional relativistic smoothed particle hydrodynamic simulation with a total ejected mass of ˜1.7 ×10-3M? . Our calculations consider an extended nuclear network, including spontaneous, ? - and neutron-induced fission and adopting fission yield distributions from the abla code. In particular we have studied the sensitivity of the r -process abundances to nuclear masses by using different models. Most of the trajectories, corresponding to 90% of the ejected mass, follow a relatively slow expansion allowing for all neutrons to be captured. The resulting abundances are very similar to each other and reproduce the general features of the observed r -process abundance (the second and third peaks, the rare-earth peak, and the lead peak) for all mass models as they are mainly determined by the fission yields. We find distinct differences in the predictions of the mass models at and just above the third peak, which can be traced back to different predictions of neutron separation energies for r -process nuclei around neutron number N =130 . In all simulations, 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 ?250 due to the substantially longer ? -decay half-lives found in this region. The third peak around A ˜195 is generated in a competition between neutron captures and ? decays during r -process freeze-out. The remaining trajectories, which contribute 10% by mass to the total integrated abundances, follow such a fast expansion that the r process does not use all the neutrons. This also leads to a larger variation of abundances among trajectories, as fission does not dominate the r -process dynamics. The resulting abundances are in between those associated to the r and s processes. The total integrated abundances are dominated by contributions from the slow abundances and hence reproduce the general features of the observed r -process abundances. We find that, at timescales of weeks relevant for kilonova light curve calculations, the abundance of actinides is larger than the one of lanthanides. This means that actinides can be even more important than lanthanides to determine the photon opacities under kilonova conditions. Moreover, we confirm that the amount of unused neutrons may be large enough to give rise to another observational signature powered by their decay.

  9. r-process Nucleosynthesis in Dynamically Ejected Matter of Neutron Star Mergers

    NASA Astrophysics Data System (ADS)

    Goriely, Stephane; Bauswein, Andreas; Janka, Hans-Thomas

    2011-09-01

    Although the rapid neutron-capture process, or r-process, is fundamentally important for explaining the origin of approximately half of the stable nuclei with A > 60, the astrophysical site of this process has not been identified yet. Here we study r-process nucleosynthesis in material that is dynamically ejected by tidal and pressure forces during the merging of binary neutron stars (NSs) and within milliseconds afterward. For the first time we make use of relativistic hydrodynamical simulations of such events, defining consistently the conditions that determine the nucleosynthesis, i.e., neutron enrichment, entropy, early density evolution and thus expansion timescale, and ejecta mass. We find that 10-3-10-2 M sun are ejected, which is enough for mergers to be the main source of heavy (A >~ 140) galactic r-nuclei for merger rates of some 10-5 yr-1. While asymmetric mergers eject 2-3 times more mass than symmetric ones, the exact amount depends weakly on whether the NSs have radii of ~15 km for a "stiff" nuclear equation of state (EOS) or ~12 km for a "soft" EOS. r-process nucleosynthesis during the decompression becomes largely insensitive to the detailed conditions because of efficient fission recycling, producing a composition that closely follows the solar r-abundance distribution for nuclei with mass numbers A > 140. Estimating the light curve powered by the radioactive decay heating of r-process nuclei with an approximative model, we expect high emission in the B-V-R bands for 1-2 days with potentially observable longer duration in the case of asymmetric mergers because of the larger ejecta mass.

  10. The r-process in the Neutrino-driven Wind from a Black-hole Torus

    NASA Astrophysics Data System (ADS)

    Wanajo, Shinya; Janka, Hans-Thomas

    2012-02-01

    We examine r-process nucleosynthesis in the neutrino-driven wind from the thick accretion disk (or "torus") around a black hole. Such systems are expected as remnants of binary neutron star or neutron star-black hole mergers. We consider a simplified, analytic, time-dependent evolution model of a 3 M ? central black hole surrounded by a neutrino emitting accretion torus with 90 km radius, which serves as basis for computing spherically symmetric neutrino-driven wind solutions. We find that ejecta with modest entropies (~30 per nucleon in units of the Boltzmann constant) and moderate expansion timescales (~100 ms) dominate in the mass outflow. The mass-integrated nucleosynthetic abundances are in good agreement with the solar system r-process abundance distribution if a minimal value of the electron fraction at the charged-particle freezeout, Y e, min ~ 0.2, is achieved. In the case of Y e, min ~ 0.3, the production of r-elements beyond A ~ 130 does not reach to the third peak but could still be important for an explanation of the abundance signatures in r-process deficient stars in the early Galaxy. The total mass of the ejected r-process nuclei is estimated to be ~1 × 10-3 M ?. If our model was representative, this demands a Galactic event rate of ~2 × 10-4 yr-1 for black-hole-torus winds from merger remnants to be the dominant source of the r-process elements. Our result thus suggests that black-hole-torus winds from compact binary mergers have the potential to be a major, but probably not the dominant, production site of r-process elements.

  11. r-PROCESS NUCLEOSYNTHESIS IN DYNAMICALLY EJECTED MATTER OF NEUTRON STAR MERGERS

    SciTech Connect

    Goriely, Stephane; Bauswein, Andreas; Janka, Hans-Thomas

    2011-09-10

    Although the rapid neutron-capture process, or r-process, is fundamentally important for explaining the origin of approximately half of the stable nuclei with A > 60, the astrophysical site of this process has not been identified yet. Here we study r-process nucleosynthesis in material that is dynamically ejected by tidal and pressure forces during the merging of binary neutron stars (NSs) and within milliseconds afterward. For the first time we make use of relativistic hydrodynamical simulations of such events, defining consistently the conditions that determine the nucleosynthesis, i.e., neutron enrichment, entropy, early density evolution and thus expansion timescale, and ejecta mass. We find that 10{sup -3}-10{sup -2} M{sub sun} are ejected, which is enough for mergers to be the main source of heavy (A {approx}> 140) galactic r-nuclei for merger rates of some 10{sup -5} yr{sup -1}. While asymmetric mergers eject 2-3 times more mass than symmetric ones, the exact amount depends weakly on whether the NSs have radii of {approx}15 km for a 'stiff' nuclear equation of state (EOS) or {approx}12 km for a 'soft' EOS. r-process nucleosynthesis during the decompression becomes largely insensitive to the detailed conditions because of efficient fission recycling, producing a composition that closely follows the solar r-abundance distribution for nuclei with mass numbers A > 140. Estimating the light curve powered by the radioactive decay heating of r-process nuclei with an approximative model, we expect high emission in the B-V-R bands for 1-2 days with potentially observable longer duration in the case of asymmetric mergers because of the larger ejecta mass.

  12. R-Process Nucleosynthesis in Dynamically Ejected Matter of Neutron Star Mergers

    E-print Network

    Stephane Goriely; Andreas Bauswein; H. -Thomas Janka

    2011-08-09

    Although the rapid neutron-capture process, or r-process, is fundamentally important for explaining the origin of approximately half of the stable nuclei with A > 60, the astrophysical site of this process has not been identified yet. Here we study r-process nucleosynthesis in material that is dynamically ejected by tidal and pressure forces during the merging of binary neutron stars (NSs) and within milliseconds afterwards. For the first time we make use of relativistic hydrodynamical simulations of such events, defining consistently the conditions that determine the nucleosynthesis, i.e., neutron enrichment, entropy, early density evolution and thus expansion timescale, and ejecta mass. We find that 10^{-3}-10^{-2} solar masses are ejected, which is enough for mergers to be the main source of heavy (A > 140) galactic r-nuclei for merger rates of some 10^{-5} per year. While asymmetric mergers eject 2-3 times more mass than symmetric ones, the exact amount depends weakly on whether the NSs have radii of ~15 km for a "stiff" nuclear equation of state (EOS) or ~12 km for a "soft" EOS. R-process nucleosynthesis during the decompression becomes largely insensitive to the detailed conditions because of efficient fission recycling, producing a composition that closely follows the solar r-abundance distribution for nuclei with mass numbers A > 140. Estimating the light curve powered by the radioactive decay heating of r-process nuclei with an approximative model, we expect high emission in the B-V-R bands for 1-2 days with potentially observable longer duration in the case of asymmetric mergers because of the larger ejecta mass.

  13. The Hamburg/ESO R-process Enhanced Star survey (HERES). IX. Constraining pure r-process Ba/Eu abundance ratio from observations of r-II stars

    NASA Astrophysics Data System (ADS)

    Mashonkina, L.; Christlieb, N.

    2014-05-01

    Context. The oldest stars born before the onset of the main s-process are expected to have a pure r-process Ba/Eu abundance ratio. Aims: We revised barium and europium abundances of selected very metal-poor (VMP) and strongly r-process enhanced (r-II) stars to evaluate an empirical r-process Ba/Eu ratio. Methods: Our calculations were based on non-local thermodynamic equilibrium (NLTE) line formation for Ba ii and Eu ii in the classical 1D MARCS model atmospheres. Homogeneous stellar abundances were determined from the Ba ii subordinate and resonance lines by applying a common Ba isotope mixture. We used high-quality VLT/UVES spectra and observational material from the literature. Results: For most investigated stars, NLTE leads to a lower Ba, but a higher Eu abundance. The resulting elemental ratio of the NLTE abundances amounts to, on average, log(Ba/Eu) = 0.78±0.06. This is a new constraint to pure r-process production of Ba and Eu. The obtained Ba/Eu abundance ratio of the r-II stars supports the corresponding solar system r-process ratio as predicted by recent Galactic chemical evolution calculations of Bisterzo, Travaglio, Gallino, Wiescher, and Käppeler. We present the NLTE abundance corrections for the Ba ii and Eu ii lines in the grid of VMP model atmospheres. Based on observations collected at the European Southern Observatory, Paranal, Chile (Proposal numbers 170.D-0010, and 280.D-5011).Tables 7 and 8 are available in electronic form at http://www.aanda.org

  14. First Results from the CARIBU Facility: Mass Measurements on the r-Process Path

    NASA Astrophysics Data System (ADS)

    Van Schelt, J.; Lascar, D.; Savard, G.; Clark, J. A.; Bertone, P. F.; Caldwell, S.; Chaudhuri, A.; Levand, A. F.; Li, G.; Morgan, G. E.; Orford, R.; Segel, R. E.; Sharma, K. S.; Sternberg, M. G.

    2013-08-01

    The Canadian Penning Trap mass spectrometer has made mass measurements of 33 neutron-rich nuclides provided by the new Californium Rare Isotope Breeder Upgrade facility at Argonne National Laboratory. The studied region includes the Sn132 double shell closure and ranges in Z from In to Cs, with Sn isotopes measured out to A=135, and the typical measurement precision is at the 100 ppb level or better. The region encompasses a possible major waiting point of the astrophysical r process, and the impact of the masses on the r process is shown through a series of simulations. These first-ever simulations with direct mass information on this waiting point show significant increases in waiting time at Sn and Sb in comparison with commonly used mass models, demonstrating the inadequacy of existing models for accurate r-process calculations.

  15. First Results from the CARIBU Facility: Mass Measurements on the r-Process Path

    E-print Network

    Van Schelt, J; Savard, G; Clark, J A; Bertone, P F; Caldwell, S; Chaudhuri, A; Levand, 1 A F; Li, G; Morgan, G E; Orford, R; Segel, R E; Sharma, K S; Sternberg, M G

    2013-01-01

    The Canadian Penning Trap mass spectrometer has made mass measurements of 33 neutron-rich nuclides provided by the new Californium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne National Laboratory. The studied region includes the 132Sn double shell closure and ranges in Z from In to Cs, with Sn isotopes measured out to A = 135, and the typical measurement precision is at the 100 ppb level or better. The region encompasses a possible major waiting point of the astrophysical r process, and the impact of the masses on the r process is shown through a series of simulations. These first-ever simulations with direct mass information on this waiting point show significant increases in waiting time at Sn and Sb in comparison with commonly used mass models, demonstrating the inadequacy of existing models for accurate r-process calculations.

  16. First Results from the CARIBU Facility: Mass Measurements on the r-Process Path

    E-print Network

    J. Van Schelt; D. Lascar; G. Savard; J. A. Clark; P. F. Bertone; S. Caldwell; A. Chaudhuri; 1 A. F. Levand; G. Li; G. E. Morgan; R. Orford; R. E. Segel; K. S. Sharma; M. G. Sternberg

    2013-07-01

    The Canadian Penning Trap mass spectrometer has made mass measurements of 33 neutron-rich nuclides provided by the new Californium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne National Laboratory. The studied region includes the 132Sn double shell closure and ranges in Z from In to Cs, with Sn isotopes measured out to A = 135, and the typical measurement precision is at the 100 ppb level or better. The region encompasses a possible major waiting point of the astrophysical r process, and the impact of the masses on the r process is shown through a series of simulations. These first-ever simulations with direct mass information on this waiting point show significant increases in waiting time at Sn and Sb in comparison with commonly used mass models, demonstrating the inadequacy of existing models for accurate r-process calculations.

  17. First results from the CARIBU facility: mass measurements on the r-process path.

    PubMed

    Van Schelt, J; Lascar, D; Savard, G; Clark, J A; Bertone, P F; Caldwell, S; Chaudhuri, A; Levand, A F; Li, G; Morgan, G E; Orford, R; Segel, R E; Sharma, K S; Sternberg, M G

    2013-08-01

    The Canadian Penning Trap mass spectrometer has made mass measurements of 33 neutron-rich nuclides provided by the new Californium Rare Isotope Breeder Upgrade facility at Argonne National Laboratory. The studied region includes the 132Sn double shell closure and ranges in Z from In to Cs, with Sn isotopes measured out to A=135, and the typical measurement precision is at the 100 ppb level or better. The region encompasses a possible major waiting point of the astrophysical r process, and the impact of the masses on the r process is shown through a series of simulations. These first-ever simulations with direct mass information on this waiting point show significant increases in waiting time at Sn and Sb in comparison with commonly used mass models, demonstrating the inadequacy of existing models for accurate r-process calculations. PMID:23971550

  18. Impact of individual nuclear masses on r-process abundances

    SciTech Connect

    Mumpower, M. R.; Surman, R.; Fang, D. -L.; Beard, M.; Möller, P.; Kawano, T.; Aprahamian, A.

    2015-09-15

    We have performed for the first time a comprehensive study of the sensitivity of r-process nucleosynthesis to individual nuclear masses across the chart of nuclides. Using the latest version (2012) of the Finite-Range Droplet Model, we consider mass variations of ±0.5 MeV and propagate each mass change to all affected quantities, including Q values, reaction rates, and branching ratios. We find such mass variations can result in up to an order of magnitude local change in the final abundance pattern produced in an r-process simulation. As a result, we identify key nuclei whose masses have a substantial impact on abundance predictions for hot, cold, and neutron star merger r-process scenarios and could be measured at future radioactive beam facilities.

  19. Evidence for supernova injection into the solar nebula and the decoupling of r-process nucleosynthesis

    PubMed Central

    Brennecka, Gregory A.; Borg, Lars E.; Wadhwa, Meenakshi

    2013-01-01

    The isotopic composition of our Solar System reflects the blending of materials derived from numerous past nucleosynthetic events, each characterized by a distinct isotopic signature. We show that the isotopic compositions of elements spanning a large mass range in the earliest formed solids in our Solar System, calcium–aluminum-rich inclusions (CAIs), are uniform, and yet distinct from the average Solar System composition. Relative to younger objects in the Solar System, CAIs contain positive r-process anomalies in isotopes A < 140 and negative r-process anomalies in isotopes A > 140. This fundamental difference in the isotopic character of CAIs around mass 140 necessitates (i) the existence of multiple sources for r-process nucleosynthesis and (ii) the injection of supernova material into a reservoir untapped by CAIs. A scenario of late supernova injection into the protoplanetary disk is consistent with formation of our Solar System in an active star-forming region of the galaxy. PMID:24101483

  20. Chemical evolution of r-process elements in the hierarchical galaxy formation

    NASA Astrophysics Data System (ADS)

    Komiya, Yutaka

    2015-08-01

    In the concordance cosmology, galaxies are formed hierarchically. Metal-poor stars in the stellar halo are thought to be relics of stars formed in dwarf galaxies in the early universe. In order to investigate metal enrichment history in the early universe, we have been built the chemical evolution model with merger trees.In this presentation, we show our results of chemical evolution computations for r-process elements. For the r-process elements, two possible astronomical sources have been proposed: supernova and coalescence of neutron star binary. Recent nucleosynthetic studies favor the neutron star merger scenario but previous chemical evolution studies pointed out difficulties. We discuss the origin of r-process elements using our hierarchical chemical evolution model.

    1. Evidence for supernova injection into the solar nebula and the decoupling of r-process nucleosynthesis.

      PubMed

      Brennecka, Gregory A; Borg, Lars E; Wadhwa, Meenakshi

      2013-10-22

      The isotopic composition of our Solar System reflects the blending of materials derived from numerous past nucleosynthetic events, each characterized by a distinct isotopic signature. We show that the isotopic compositions of elements spanning a large mass range in the earliest formed solids in our Solar System, calcium-aluminum-rich inclusions (CAIs), are uniform, and yet distinct from the average Solar System composition. Relative to younger objects in the Solar System, CAIs contain positive r-process anomalies in isotopes A < 140 and negative r-process anomalies in isotopes A > 140. This fundamental difference in the isotopic character of CAIs around mass 140 necessitates (i) the existence of multiple sources for r-process nucleosynthesis and (ii) the injection of supernova material into a reservoir untapped by CAIs. A scenario of late supernova injection into the protoplanetary disk is consistent with formation of our Solar System in an active star-forming region of the galaxy. PMID:24101483

    2. Beta-decay spectroscopy relevant to the r-process nucleosynthesis

      SciTech Connect

      Nishimura, Shunji; Collaboration: RIBF Decay Collaboration

      2012-11-12

      A scientific program of beta-decay spectroscopy relevant to r-process nucleosynthesis has been started using high intensity U-beam at the RIBF. The first results of {beta}-decay half-lives of very neutron-rich Kr to Tc nuclides, all of which lie close to the r-process path, suggest a systematic enhancement of the the {beta}-decay rates of the Zr and Nb isotopes around A110 with respect to the predictions of the deformed quasiparticle-random-phase-approximation model (FRDM + QRPA). An impact of the results on the astrophysical r-process is discussed together with the future perspective of the {beta}-decay spectroscopy with the EURICA.

    3. Statistical Global Model of beta- Half-lives and r-Process Nucleosynthesis

      E-print Network

      N. J. Costiris; E. Mavrommatis; K. A. Gernoth; J. W. Clark

      2013-09-02

      Purpose: Our objective is to apply an improved statistical global model of beta^- decay half-life systematics [1] generated by machine-learning techniques to the prediction of beta half-lives relevant to r-process nuclei. The primary aim of this application is to complement existing r-process-clock and matter-flow studies, thereby providing additional theoretical support for the planning of future activities of the world's network of rare-isotope laboratories. Results: Results are presented for nuclides situated on the r-ladders at N=50, 82, and 126 where abundances peak, as well as for nuclides that affect abundances between peaks or may be relevant to r-processes under different astrophysical scenarios. The half-lives of some of the targeted neutron-rich nuclides have either been recently measured or will be accessible at rare-isotope laboratories in the relatively near future. The results of our large-scale data-driven half-life calculations (generated by a "theory-thin" global statistical model) are compared to available experimental data, including recent measurements on very neutron-rich nuclei along an r-process path far from the valley of $\\beta$ stability. Comparison is also made with corresponding results from traditional global models derived by semi-phenomenological "theory-thick" approaches.

    4. Observations of the r-Process in Galactic Halo Stars: Successes and Frustrations

      NASA Astrophysics Data System (ADS)

      Sneden, Chris

      2010-11-01

      Our understanding of early Galactic nucleosynthesis was fundamentally changed in the 1980s and 1990s by the serendipitous discovery of a few stars with extremely large abundance enhancements of neutron-capture (Z>30) elements. Detailed spectroscopic analyses of these stars revealed their neutron-capture abundance ratios to be well-matched by the solar-system r-process-only distribution. Subsequent work has significantly sharpened our knowledge of the r-process in low-metallicity Galactic halo stars. Astronomers have found many more r-rich stars and have analyzed them in often excruciating detail; lab atomic physicists have radically altered the quantity and quality of atomic transition data; nuclear experimental physicists have improved reaction rates away from the valley of beta stability; and theoretical nuclear physicists have begun to make realistic r-process abundance predictions. Here I will summarize our observational knowledge of the r-process in stars, trying to distinguish between those results which undoubtedly will stand the test of time, and those still much in need of further development. Suggestions will be given for profitable future studies by astronomers, and requests for vital parallel investigations by physicists.

    5. Neutron capture on 130Sn during r-process freeze-out

      E-print Network

      J. Beun; J. C. Blackmon; W. R. Hix; G. C. McLaughlin; M. S. Smith; R. Surman

      2008-06-24

      We examine the role of neutron capture on 130Sn during r-process freeze-out in the neutrino-driven wind environment of the core-collapse supernova. We find that the global r-process abundance pattern is sensitive to the magnitude of the neutron capture cross section of 130Sn. The changes to the abundance pattern include not only a relative decrease in the abundance of 130Sn and an increase in the abundance of 131Sn, but also a shift in the distribution of material in the rare earth and third peak regions.

    6. Beta decay studies of r-process nuclei at the National Superconducting Cyclotron Laboratory

      E-print Network

      J. Pereira; A. Aprahamian; O. Arndt; A. Becerril; T. Elliot; A. Estrade; D. Galaviz; S. Hennrich; P. Hosmer; R. Kessler; K. -L. Kratz; G. Lorusso; P. F. Mantica; M. Matos; F. Montes; P. Santi; B. Pfeiffer; M. Quinn; H. Schatz; F. Schertz; L. Schnorrenberger; E. Smith; B. E. Tomlin; W. Walters; A. Wohr

      2009-01-13

      The impact of nuclear physics on astrophysical r-process models is discussed, emphasizing the importance of beta-decay properties of neutron-rich nuclei. Several r-process motivated beta-decay experiments performed at the National Superconducting Cyclotron Laboratory are presented. The experiments include the measurement of beta-decay half-lives and neutron emission probabilities of nuclei in regions around Ni-78; Se-90; Zr-106 and Rh-120, as well as spectroscopic studies of Pd-120. A summary on the different experimental techniques employed, data analysis, results and impact on model calculations is presented.

    7. Investigating ?-decay properties of spherical nuclei along the possible r-process path

      NASA Astrophysics Data System (ADS)

      Fang, Dong-Liang; Brown, B. Alex; Suzuki, Toshio

      2013-09-01

      The spherical quasiparticle random-phase approximation method is used for calculations of the ?-decay properties of neutron-rich nuclei in the region near the neutron magic numbers N=82 and N=126 which are important for determination of the r-process path. Our calculations differ from previous works by the use of realistic forces for the proton-neutron interaction. Both allowed and first-forbidden ? decays are included. Detailed comparisons with the experimental measurements and the previous shell-model calculations are performed. The results for half-lives and ?-delayed neutron emission probabilities will serve as input for r-process nucleosynthesis simulations.

    8. Neutron Capture on 130Sn during r-Process Freeze-Out

      SciTech Connect

      Beun, Joshua; Blackmon, Jeffery C; Hix, William Raphael; Mclaughlin, Gail C; Smith, Michael Scott; Surman, Rebecca

      2009-01-01

      We examine the role of neutron capture on {sup 130}Sn during r-process freeze-out in the neutrino-driven wind environment of the core-collapse supernova. We find that the global r-process abundance pattern is sensitive to the magnitude of the neutron capture cross section of {sup 130}Sn. The changes to the abundance pattern include not only a relative decrease in the abundance of {sup 130}Sn and an increase in the abundance of {sup 131}Sn, but also a shift in the distribution of material in the rare earth and third peak regions.

    9. Beta Decays of Isotones with Neutron Magic Number of N=126 and R-process Nucleosynthesis

      E-print Network

      Toshio Suzuki; Takashi Yoshida; Toshitaka Kajino; Takaharu Otsuka

      2011-12-16

      Beta decays of the isotones with N=126 are studied by shell model calculations taking into account both the Gamow-Teller (GT) and first-forbidden (FF) transitions. The FF transitions are found to be important to reduce the half-lives, by nearly twice to several times, from those by the GT contributions only. Possible implications of the short half-lives of the waiting point nuclei on the r-process nucleosynthesis during the supernova explosions are discussed. A slight shift of the third peak of the element abundances in the r-process toward higher mass region is found.

    10. Long, cold, early r process? Neutrino-induced nucleosynthesis in He shells revisited.

      PubMed

      Banerjee, Projjwal; Haxton, W C; Qian, Yong-Zhong

      2011-05-20

      We revisit a ?-driven r-process mechanism in the He shell of a core-collapse supernova, finding that it could succeed in early stars of metallicity Z ? 10?³ Z(?), at relatively low temperatures and neutron densities, producing A ~ 130 and 195 abundance peaks over ~10-20 s. The mechanism is sensitive to the ? emission model and to ? oscillations. We discuss the implications of an r process that could alter interpretations of abundance data from metal-poor stars, and point out the need for further calculations that include effects of the supernova shock. PMID:21668217

    11. Compact binary mergers as the origin of r-process elements in the Galactic halo

      SciTech Connect

      Ishimaru, Yuhri; Wanajo, Shinya; Prantzos, Nikos

      2014-05-02

      Compact binary mergers (of double neutron star and black hole-neutron star systems) are suggested to be the major site of the r-process elements in the Galaxy by recent hydrodynamical and nucleosynthesis studies. It has been pointed out, however, that estimated long lifetimes of compact binaries are in conflict with the presence of r-process-enhanced stars at the metallicity [Fe/H] ? ?3. To resolve this problem, we examine the role of compact binary mergers in the early Galactic chemical evolution on the assumption that our Galactic halo was formed from merging sub-halos. The chemical evolutions are modeled for sub-halos with their total stellar masses between 10{sup 4}M{sub ?} and 2 × 10{sup 8}M{sub ?}. The lifetimes of compact binaries are assumed to be 100 Myr (95%) and 1 Myr (5%) according to recent binary population synthesis studies. We find that the r-process abundances (relative to iron; [r/Fe]) start increasing at [Fe/H] ? ?3 if the star formation rates are smaller for less massive sub-halos. Our models also suggest that the star-to-star scatter of [r/Fe]'s observed in Galactic halo stars can be interpreted as a consequence of greater gas outflow rates for less massive sub-halos. In addition, the sub-solar [r/Fe]'s (observed as [Ba/Fe] ? ?1.5 for [Fe/H] < ?3) are explained by the contribution from the short-lived (? 1 Myr) binaries. Our result indicates, therefore, that compact binary mergers can be potentially the origin of the r-process elements throughout the Galactic history.

    12. Approaching the precursor nuclei of the third r-process peak with RIBs

      E-print Network

      C. Domingo-Pardo; R. Caballero-Folch; J. Agramunt; A. Algora; A. Arcones; F. Ameil; Y. Ayyad; J. Benlliure; M. Bowry; F. Calviño; D. Cano-Ott; G. Cortés; T. Davinson; I. Dillmann; A. Estrade; A. Evdokimov; T. Faestermann; F. Farinon; D. Galaviz; A. García-Rios; H. Geissel; W. Gelletly; R. Gernhäuser; M. B. Gómez-Hornillos; C. Guerrero; M. Heil; C. Hinke; R. Knöbel; I. Kojouharov; J. Kurcewicz; N. Kurz; Y. Litvinov; L. Maier; J. Marganiec; M. Marta; T. Martínez; G. Martínez-Pinedo; B. S. Meyer; F. Montes; I. Mukha; D. R. Napoli; Ch. Nociforo; C. Paradela; S. Pietri; Z. Podolyák; A. Prochazka; S. Rice; A. Riego; B. Rubio; H. Schaffner; Ch. Scheidenberger; K. Smith; E. Sokol; K. Steiger; B. Sun; J. L. Taín; M. Takechi; D. Testov; H. Weick; E. Wilson; J. S. Winfield; R. Wood; P. Woods; A. Yeremin

      2013-09-13

      The rapid neutron nucleosynthesis process involves an enormous amount of very exotic neutron-rich nuclei, which represent a theoretical and experimental challenge. Two of the main decay properties that affect the final abundance distribution the most are half-lives and neutron branching ratios. Using fragmentation of a primary $^{238}$U beam at GSI we were able to measure such properties for several neutron-rich nuclei from $^{208}$Hg to $^{218}$Pb. This contribution provides a short update on the status of the data analysis of this experiment, together with a compilation of the latest results published in this mass region, both experimental and theoretical. The impact of the uncertainties connected with the beta-decay rates and with beta-delayed neutron emission is illustrated on the basis of $r$-process network calculations. In order to obtain a reasonable reproduction of the third $r$-process peak, it is expected that both half-lives and neutron branching ratios are substantially smaller, than those based on FRDM+QRPA, commonly used in $r$-process model calculations. Further measurements around $N\\sim126$ are required for a reliable modelling of the underlying nuclear structure, and for performing more realistic $r$-process abundance calculations.

    13. The impact of individual nuclear properties on $r$-process nucleosynthesis

      E-print Network

      M. R. Mumpower; R. Surman; G. C. McLaughlin; A. Aprahamian

      2015-08-28

      The astrophysical rapid neutron capture process or `$r$ process' of nucleosynthesis is believed to be responsible for the production of approximately half the heavy element abundances found in nature. This multifaceted problem remains one of the greatest open challenges in all of physics. Knowledge of nuclear physics properties such as masses, $\\beta$-decay and neutron capture rates, as well as $\\beta$-delayed neutron emission probabilities are critical inputs that go into calculations of $r$-process nucleosynthesis. While properties of nuclei near stability have been established, much still remains unknown regarding neutron-rich nuclei far from stability that may participate in the $r$ process. Sensitivity studies gauge the astrophysical response of a change in nuclear physics input(s) which allows for the isolation of the most important nuclear properties that shape the final abundances observed in nature. This review summarizes the extent of recent sensitivity studies and highlights how these studies play a key role in facilitating new insight into the $r$ process. The development of these tools promotes a focused effort for state-of-the-art measurements, motivates construction of new facilities and will ultimately move the community towards addressing the grand challenge of `How were the elements from iron to uranium made?'.

    14. Positioning the neutron drip line and the r-process paths in the nuclear landscape

      NASA Astrophysics Data System (ADS)

      Wang, Rui; Chen, Lie-Wen

      2015-09-01

      Exploring nucleon drip lines and astrophysical rapid neutron capture process (r-process) paths in the nuclear landscape is extremely challenging in nuclear physics and astrophysics. While various models predict a similar proton drip line, their predictions for the neutron drip line and the r-process paths involving heavy neutron-rich nuclei exhibit a significant variation which hampers our accurate understanding of the r-process nucleosynthesis mechanism. By using microscopic density functional theory with a representative set of nonrelativistic and relativistic interactions, we demonstrate for the first time that this variation is mainly due to the uncertainty of nuclear matter symmetry energy Esym(?sc) at the subsaturation cross density ?sc=0.11 /0.16 ×?0 (?0 is saturation density), which reflects the symmetry energy of heavy nuclei. By using the recent accurate constraint on Esym(?sc) from the binding-energy difference of heavy-isotope pairs, we obtain quite precise predictions for the location of the neutron drip line, the r-process paths, and the number of bound nuclei in the nuclear landscape. Our results have important implications on extrapolating the properties of unknown neutron-rich rare isotopes from the data on known nuclei.

    15. WASTE PROCESSING ANNUAL NUCLEAR SAFETY RELATED R AND D REPORT FOR CY2008

      SciTech Connect

      Fellinger, A.

      2009-10-15

      The Engineering and Technology Office of Waste Processing identifies and reduces engineering and technical risks associated with key waste processing project decisions. The risks, and actions taken to mitigate those risks, are determined through technology readiness assessments, program reviews, technology information exchanges, external technical reviews, technical assistance, and targeted technology development and deployment (TDD). The Office of Waste Processing TDD program prioritizes and approves research and development scopes of work that address nuclear safety related to processing of highly radioactive nuclear wastes. Thirteen of the thirty-five R&D approved work scopes in FY2009 relate directly to nuclear safety, and are presented in this report.

    16. The R-Process Supernovae and Other Sources of the Heaviest Elements

      NASA Astrophysics Data System (ADS)

      Thielemann, F.-K.; Mocelj, D.; Panov, I.; Kolbe, E.; Rauscher, T.; Kratz, K.-L.; Farouqi, K.; Pfeiffer, B.; Martinez-Pinedo, G.; Kelic, A.; Langanke, K.; Schmidt, K.-H.; Zinner, N.

      Rapid neutron capture in stellar explosions is responsible for the heaviest elements in nature, up to Th, U and beyond. This nucleosynthesis process, the r-process, is unique in the sense that a combination of nuclear physics far from stability (masses, half-lives, neutron-capture and photodisintegration, neutron-induced and beta-delayed fission and last but not least neutrino-nucleus interactions) is intimately linked to ejecta from astrophysical explosions (core collapse supernovae or other neutron star related events). The astrophysics and nuclear physics involved still harbor many uncertainties, either in the extrapolation of nuclear properties far beyond present experimental explorations or in the modeling of multidimensional, general relativistic (neutrino-radiation) hydrodynamics with rotation and possibly required magnetic fields. Observational clues about the working of the r-process are mostly obtained from solar abundances and from the abundance evolution of the heaviest elements as a function of galactic age, as witnessed in old extremely metal-poor stars. They contain information whether the r-process is identical for all stellar events, how abundance features develop with galactic time and whether the frequency of r-process events is comparable to that of average core collapse supernovae - producing oxygen through titanium, as well as iron-group nuclei. The theoretical modeling of the r-process has advanced from simple approaches, where the use of static neutron densities and temperatures can aid to test the influence of nuclear properties far from stability on abundance features, to more realistic expansions with a given entropy, global neutron/proton ratio and expansion timescales, as expected from explosive astrophysical events. The direct modeling in astrophysical events such as supernovae still faces the problem whether the required conditions can be met.

    17. Development of Highly Efficient Saving Processes of Rare Earth in R-T-B Permanent Magnet

      NASA Astrophysics Data System (ADS)

      Saguchi, A.; Uesugi, T.; Takigawa, Y.; Higashi, K.

      In this study, cost reduction of manufacturing R (Nd, Pr, and Dy) -T (Fe, Co)-B permanent magnets was investigated. An efficient direct melting recycle of R-T-B magnet scraps and multiple methods for saving Dy were focused. In the former, Decarburization and deoxidation of R-T-B magnet scraps were developed as a pre-treatment technique for conventional induction melting. The decarburized scraps 0.001mass% carbon or less was subsequently deoxidized by calciothermic reduction. The recycled scraps can be used as low cost alloying elements by re-melting. In the latter, the casting conditions for R-T-B alloy with small admixture of Ga and the improved pulverization process of R-T-B magnet alloy were developed. Microstructure of R-T-B magnet alloy with small admixture Ga was optimized by controlling cooling rate during solidification, and its average crystalline size was to be 5 ?m. In order to obtain finer R-T-B magnet alloy powder preferable to the coercive force, conditions of hydrogen decrepitation (HD) prior to pulverization were optimized. Specific surface area of the HD magnet alloy was increased with decreasing temperature and hydrogen pressure, and its grindability was verified by Jet milling.

    18. Using RBF-Nets in Rubber Industry Process Control U. Pietruschka, R. Brause

      E-print Network

      Brause, R.

      Using RBF-Nets in Rubber Industry Process Control U. Pietruschka, R. Brause J.W. Goethe of a rubber profile used in tyre production. After introducing the problem, we describe the RBF net algorithm in rubber industry has the smell of a ,,dirty" industrial branch. This comes not only from the often very

    19. Umbrella sampling for nonequilibrium processes Aryeh Warmflash, Prabhakar Bhimalapuram, and Aaron R. Dinnera

      E-print Network

      Dinner, Aaron

      Umbrella sampling for nonequilibrium processes Aryeh Warmflash, Prabhakar Bhimalapuram, and Aaron R. By enforcing equal sampling of different regions of phase space, as in umbrella sampling simulations of systems sampling methods, in which biasing potentials that are functions of one or more order parameters are used

    20. New fission fragment distributions and r-process origin of the rare-earth elements

      E-print Network

      Goriely, S; Lemaitre, J -F; Panebianco, S; Dubray, N; Hilaire, S; Bauswein, A; Janka, H -Thomas

      2013-01-01

      Neutron star (NS) merger ejecta offer a viable site for the production of heavy r-process elements with nuclear mass numbers A > 140. The crucial role of fission recycling is responsible for the robustness of this site against many astrophysical uncertainties, but calculations sensitively depend on nuclear physics. In particular the fission fragment yields determine the creation of 110 140.

    1. OPACITIES AND SPECTRA OF THE r-PROCESS EJECTA FROM NEUTRON STAR MERGERS

      SciTech Connect

      Kasen, Daniel; Barnes, Jennifer; Badnell, N. R.

      2013-09-01

      Material ejected during (or immediately following) the merger of two neutron stars may assemble into heavy elements through the r-process. The subsequent radioactive decay of the nuclei can power transient electromagnetic emission similar to, but significantly dimmer than, an ordinary supernova. Identifying such events is an important goal of future optical surveys, offering new perspectives on the origin of r-process nuclei and the astrophysical sources of gravitational waves. Predictions of the transient light curves and spectra, however, have suffered from the uncertain optical properties of heavy ions. Here we argue that the opacity of an expanding r-process material is dominated by bound-bound transitions from those ions with the most complex valence electron structure, namely the lanthanides. For a few representative ions, we run atomic structure models to calculate the radiative transition rates for tens of millions of lines. The resulting r-process opacities are orders of magnitude larger than that of ordinary (e.g., iron-rich) supernova ejecta. Radiative transport calculations using these new opacities suggest that the light curves should be longer, dimmer, and redder than previously thought. The spectra appear to be pseudo-blackbody, with broad absorption features, and peak in the infrared ({approx}1 {mu}m). We discuss uncertainties in the opacities and attempt to quantify their impact on the spectral predictions. The results have important implications for observational strategies to find and study the radioactively powered electromagnetic counterparts to neutron star mergers.

    2. Relative contributions of the weak, main and fission-recycling r-process

      E-print Network

      Shibagaki, S; Mathews, G J; Chiba, S; Nishimura, S; Lorusso, G

      2015-01-01

      There has been a persistent conundrum in attempts to model the nucleosynthesis of heavy elements by rapid neutron capture (the $r$-process). Although the location of the abundance peaks near nuclear mass numbers 130 and 195 identify an environment of rapid neutron capture near closed nuclear shells, the abundances of elements just above and below those peaks are often underproduced by more than an order of magnitude in model calculations. At the same time there is a debate in the literature as to what degree the $r$-process elements are produced in supernovae or the mergers of binary neutron stars. In this paper we propose a novel solution to both problems. We demonstrate that the underproduction of elements above and below the $r$-process peaks characteristic in the main or weak $r$-process events (like magnetohydrodynamic jets or neutrino-driven winds in core-collapse supernovae) can be supplemented via fission fragment distributions from the recycling of material in a neutron-rich environment such as that ...

    3. Long gamma-ray burst as a production site of r-process elements

      SciTech Connect

      Nakamrua, Ko; Harikae, Seiji; Kajino, Toshitaka; Mathews, Grant J.

      2012-11-12

      We simulated the r-process nucleosynthesis in and around a high entropy jet from a long gamma-ray burst (GRB). Our simulation is based on the collapsar scenario for long GRBs and on relativistic magnetohydrodynamic simulations (Harikae et al. 2009, 2010) including ray-tracing neutrino transport, which describe the development of the black hole accretion disk and the heating of the funnel region to produce a relativistic jet. The time evolution of the jet was then extended to later phase via axi-symmetric special relativistic hydrodynamic simulation to follow the temperature, entropy, electron fraction, and density evolution for representative test particles. The evolution of nuclear abundances from nucleons to heavy nuclei for representative test particle trajectories was solved in a large nuclear reaction network including more than 5000 isotopes. We show that a robust r-process successfully occurs within the collapsar jet outflow and that sufficient mass is ejected within the flow to account for the observed r-process abundance distribution along with the large dispersion in r-process elements observed in metal-poor halo stars.

    4. Inhomogeneous Galactic halo: a possible explanation for the spread observed in s- and r- process elements

      E-print Network

      G. Cescutti

      2007-02-21

      The considerable scatter of the s- and r-process elements observed in low-metallicity stars, compared to the small star to star scatter observed for the alpha elements, is an open question for the chemical evolution studies. We have developed a stochastic chemical evolution model, in which the main assumption is a random formation of new stars, subject to the condition that the cumulative mass distribution follows a given initial mass function. With our model we are able to reproduce the different features of alpha-elements and s-and r-process elements. The reason for this resides in the random birth of stellar masses coupled with the different stellar mass ranges from where alpha-elements and s-and r-process elements originate. In particular, the sites of production of the alpha elements are the whole range of the massive stars, whereas the mass range of production for the s- and r-process elements has an upper limit of 30 solar masses.

    5. r-process nucleosynthesis in the MHD+neutrino-heated collapsar jet

      NASA Astrophysics Data System (ADS)

      Nakamura, K.; Kajino, T.; Mathews, G. J.; Sato, S.; Harikae, S.

      2015-10-01

      It has been proposed that the collapsar scenario for long-duration gamma ray bursts is a possible astrophysical site for r-process nucleosynthesis. Here we present r-process nucleosynthesis calculations based upon a model for a MHD+neutrino-heated collapsar jet. We utilize a relativistic magnetohydrodynamic model that includes ray-tracing neutrino transport to describe the development of the black hole accretion disk and the neutrino heating of the funnel region above the black hole. The late time evolution of the collapsar jet is then evolved using axisymmetric special relativistic hydrodynamics. We employ representative test particles to follow the trajectories in density, temperature, entropy, and electron fraction for material flowing from the accretion disk into the jet until they are several thousand km above the black hole. The evolution of nuclear abundances from nucleons to heavy nuclei for ejected test particle trajectories was solved in a large nuclear reaction network as temperatures fall from 9 × 109 to 3 × 108 K. We show that an r-process-like abundance distribution forms in material ejected in the collapsar jet. The possibility for a signature of collapsar r-process material to be found in metal-poor stars is discussed.

    6. Introduction: linked processes of metamorphism and deformation A. R. STALLARD1

      E-print Network

      Solar, Gary S.

      Introduction: linked processes of metamorphism and deformation A. R. STALLARD1 AND G. SOLAR2 1 Avenue, Buffalo, New York, USA (solargs@buffalostate.edu) The interaction of deformation and metamorphism activity as well as the progressive metamorphic and structural development of the crust. Analysis

    7. r-Process Elements in EMP stars: Indicators of Inhomogeneous Early Halo Enrichment

      NASA Astrophysics Data System (ADS)

      Andersen, Johannes; Nordström, Birgitta; Thidemann Hansen, Terese

      2015-08-01

      Extremely metal-poor (EMP) halo stars with [Fe/H] below ~ -3 are considered to be fossil records of conditions in the early halo. In the simplest picture where iron is a proxy for overall metallicity and indirectly for time, EMP stars formed before the oldest and most metal-poor Galactic globular clusters. High-resolution spectroscopy with 8m-class telescopes has shown the detailed abundance pattern of these stars to be surprisingly uniform (e.g. Bonifacio+ 2012) and essentially Solar, apart from the ?-enhancement typical of SN II nucleosynthesis. A small fraction (~3%) of EMP stars, however, is strongly enhanced in the heaviest (r-process) neutron-capture elements, highlighting that the periodic system of elements was fully populated already this early.These striking departures from the general chemical homogeneity could be produced by local or distant sources. The former case is simple - mass transfer from a binary companion that evolved to produce a highly neutron-rich environment (one or more NS). Alternatively, the r-process elements were formed in a site at interstellar distance and preferentially seeded into the natal clouds of the present-day EMP-r stars. Our long-term, precise monitoring of the radial velocities of a sample of such stars (Hansen+ 2011) disproved the binary hypothesis, which would in fact also fail to explain the existence of r-process poor stars, such as HD 122653. We thus conclude that the chemical enrichment of the early halo was far more complex, patchy and likely anisotropic than assumed in current models of Galactic chemical evolution: The EMP-r stars are not just peculiarities to be ignored, but indicate that a new level of complexity must be invoked. That r-process elements have not (yet) been observed in high-redshift DLA systems is readily explained by their low abundance relative to the lighter species and the rarity of strong enrichment events.

    8. In Vitro Processing of the 16S rRNA of the Thermophilic Archaeon Sulfolobus solfataricus

      PubMed Central

      Ciammaruconi, Andrea; Londei, Paola

      2001-01-01

      In this paper we have analyzed the processing in vitro of the 16S rRNA of the thermophilic archaeon Sulfolobus solfataricus, using pre-rRNA substrates transcribed in vitro and different protein preparations as the source of processing enzymes. We show that the 5? external transcribed spacer of the S. solfataricus pre-rRNA transcript contains a target site for a specific endonuclease, which recognizes a conserved sequence also existing in the early A0 and 0 processing sites of Saccharomyces cerevisiae and vertebrates. This site is present in other members of the kingdom Crenarchaeota but apparently not in the Euryarchaeota. Furthermore, S. solfataricus pre-16S RNA is processed within the double-helical stem formed by the inverted repeats flanking the 16S RNA sequence, in correspondence with a bulge-helix-bulge motif. The endonuclease responsible for this cleavage is present in both the Crenarchaeota and the Euryarchaeota. The processing pattern remained the same when the substrate was a 30S ribonucleoprotein particle instead of the naked RNA. Maturation of either the 5? or the 3? end of the 16S RNA molecule was not observed, suggesting either that maturation requires conditions not easily reproducible in vitro or that the responsible endonucleases are scarcely represented in cell extracts. PMID:11395449

    9. Cerebral Processing of Prosodic Emotional Signals: Evaluation of a Network Model Using rTMS

      PubMed Central

      Plewnia, Christian; Wildgruber, Dirk

      2014-01-01

      A great number of functional imaging studies contributed to developing a cerebral network model illustrating the processing of prosody in the brain. According to this model, the processing of prosodic emotional signals is divided into three main steps, each related to different brain areas. The present study sought to evaluate parts of the aforementioned model by using low-frequency repetitive transcranial magnetic stimulation (rTMS) over two important brain regions identified by the model: the superior temporal cortex (Experiment 1) and the inferior frontal cortex (Experiment 2). The aim of both experiments was to reduce cortical activity in the respective brain areas and evaluate whether these reductions lead to measurable behavioral effects during prosody processing. However, results obtained in this study revealed no rTMS effects on the acquired behavioral data. Possible explanations for these findings are discussed in the paper. PMID:25171220

    10. Economic analysis: impact of CS/R process on benzene market

      SciTech Connect

      Spielberger, L.; Klein, J.

      1981-05-01

      Contract No. DE-AC01-78ET10159 (formerly ET-78-C-01-3117) between UOP/SDC and the United States Department of Energy (DOE) requires UOP/SDC to provide specific engineering and technical services to the DOE Office of Coal Processing in support of the Coal Gasification Program. This report covers an economic study on the projected price of benzene through the next decade based on the market factors and production costs. The impact of the CS/R process on the benzene market was evaluated. In addition, the cost of gas from the CS/R process was determined as a function of the byproduct credit for benzene.

    11. Realistic fission models, new beta-decay half-lives and the r-process in neutron star mergers

      SciTech Connect

      Shibagaki, S.; Kajino, T.; Chiba, S.; Lorusso, G.; Nishimura, S.; Mathews, G. J.

      2014-05-02

      Almost half of heavy nuclei beyond iron are considered to be produced by rapid neutron capture process (r-process). This process occurs in the neutron-rich environment such as core-collapse supernovae or neutron star mergers, but the main production site is still unknown. In the r-process of neutron star mergers, nuclear fission reactions play an important role. Also beta-decay half-lives of magic nuclei are crucial for the r-process. We have carried out r-process nucleosynthesis calculations based upon new theoretical estimates of fission fragment distributions and new beta-decay half-lives for N=82 nuclei measured at RIBF-RIKEN. We investigate the effect of nuclear fission on abundance patterns in the matter ejected from neutron star mergers with two different fission fragment mass distributions. We also discuss how the new experimental beta-decay half-lives affect the r-process.

    12. CIS Modules Process R&D: Final Technical Report, October 2005 - June 2006

      SciTech Connect

      Tarrant, D. E.; Gay, R. R.

      2006-07-01

      The primary objectives of this subcontract were to: address key near-term technical R&D issues for continued improvement in thin-film PV products; continue process development for increased production capacity; pursue long-term R&D contributing to progress toward the MYTP goals for 2020 to increase the conversion efficiency to 15% and reduce module manufacturing costs to less than $50/m2, thus enabling PV systems with a 30-year lifetime at an installed cost of under $2.00/W; and advance the understanding of the requirements needed to achieve better thin-film PV cell and module performance, greater reliability and market acceptance, and investigate materials systems and new devices that can improve the cost/performance ratio of future thin-film PV factories. The demonstrated and maintained high production yield is a major accomplishment supporting attractive cost projections for CIS. Process R&D at successive levels of CIS production has led to the continued demonstration of the prerequisites for commitment to large-scale commercialization. Process and packaging R&D during this and previous subcontracts has demonstrated the potential for further cost and performance improvements.

    13. Identification of miR-145 as a key regulator of the pigmentary process.

      PubMed

      Dynoodt, Peter; Mestdagh, Pieter; Van Peer, Gert; Vandesompele, Jo; Goossens, Karen; Peelman, Luc J; Geusens, Barbara; Speeckaert, Reinhart M; Lambert, Jo L W; Van Gele, Mireille J L

      2013-01-01

      The current treatments for hyperpigmentation are often associated with a lack of efficacy and adverse side effects. We hypothesized that microRNA (miRNA)-based treatments may offer an attractive alternative by specifically targeting key genes in melanogenesis. The aim of this study was to identify miRNAs interfering with the pigmentary process and to assess their functional role. miRNA profiling was performed on mouse melanocytes after three consecutive treatments involving forskolin and solar-simulated UV (ssUV) irradiation. Sixteen miRNAs were identified as differentially expressed in treated melan-a cells versus untreated cells. Remarkably, a 15-fold downregulation of miR-145 was detected. Overexpression or downregulation of miR-145 in melan-a cells revealed reduced or increased expression of Sox9, Mitf, Tyr, Trp1, Myo5a, Rab27a, and Fscn1, respectively. Moreover, a luciferase reporter assay demonstrated direct targeting of Myo5a by miR-145 in mouse and human melanocytes. Immunofluorescence tagging of melanosomes in miR-145-transfected human melanocytes displayed perinuclear accumulation of melanosomes with additional hypopigmentation of harvested cell pellets. In conclusion, this study has established an miRNA signature associated with forskolin and ssUV treatment. The significant down- or upregulation of major pigmentation genes, after modulating miR-145 expression, suggests a key role for miR-145 in regulating melanogenesis. PMID:22895360

    14. New fission fragment distributions and r-process origin of the rare-earth elements

      E-print Network

      S. Goriely; J. -L. Sida; J. -F. Lemaitre; S. Panebianco; N. Dubray; S. Hilaire; A. Bauswein; H. -Thomas Janka

      2013-11-22

      Neutron star (NS) merger ejecta offer a viable site for the production of heavy r-process elements with nuclear mass numbers A > 140. The crucial role of fission recycling is responsible for the robustness of this site against many astrophysical uncertainties, but calculations sensitively depend on nuclear physics. In particular the fission fragment yields determine the creation of 110 rare-earth peak that is nicely compatible with the abundance patterns in the Sun and metal-poor stars. This new finding further strengthens the case of NS mergers as possible dominant origin of r-nuclei with A > 140.

    15. r-Process Nucleosynthesis in Magnetohydrodynamic Jet Explosions of Core-Collapse Supernovae

      NASA Astrophysics Data System (ADS)

      Nishimura, Sunao; Kotake, Kei; Hashimoto, Masa-aki; Yamada, Shoichi; Nishimura, Nobuya; Fujimoto, Shinichiro; Sato, Katsuhiko

      2006-05-01

      We investigate the r-process nucleosynthesis during a purely magnetohydrodynamic (MHD) explosion in a massive star of 13 Msolar. The two-dimensional MHD simulations have been carried out from the onset of the core collapse to the shock propagation to the silicon-rich layers (~500 ms after bounce). Thereafter, using the compositions during the explosion, we calculate the r-process nucleosynthesis in the later phase by employing the two kinds of time extrapolations of the temperature and density. With these computations, we show that the jetlike explosion formed due to the combined effects of rapid rotation and strong magnetic field lowers the electron fraction significantly in the iron core, contrary to the spherical explosion. We demonstrate that the ejected material with low Ye in the jet coming out from the silicon layers is good for reproducing the third peak of the solar r-element pattern. In addition, we investigate the effects of fission using the full nuclear reaction network and the differences of two kinds of mass formulae on the r-process peaks obtained in the above MHD models. As a result, we find that both of them can reproduce the global abundance pattern up to the third peaks, although the detailed distributions are rather different. Finally, we discuss the effects of neutrino absorption reactions, which are not coupled to the above MHD simulations, on the possible reduction of Ye obtained in the above computations. We point out that there should be variations in the r-process nucleosynthesis in the supernova explosion if the MHD effects play an important role.

    16. Neutron Star - Core Merger as a Rare R-process Site

      E-print Network

      Papish, Oded

      2013-01-01

      We raise the possibility that strong r-process nucleosynthesis occurs inside jets launched by a neutron star (NS) spiraling-in inside the core of a red supergiant star. The strong r-process is the one where elements with high atomic weight of A>130 are formed. A NS in a common envelope (CE) with a massive red supergiant star is a very rare evolutionary route. This can account for the large variations in r-process elements bundances in the early evolution of the galaxy. We estimate the properties of the jets launched by the NS and their interaction with the giant material by using the jet-feedback mechanism, where energy deposited by the jets drives the ejection of the envelope and core. The jet feedback mechanism implies that Thorne-Zytkow objects cannot be produced via CE evolution. We compare the properties of these CE-NS jets with jets that are launched by a newly formed neutron star in core collapse supernovae (CCSNe). We find that the lower neutrino flux and longer duration of the process in the rare cas...

    17. The History of R-Process Enrichment in the Milky Way

      NASA Astrophysics Data System (ADS)

      Shen, Sijing; Cooke, Ryan J.; Ramirez-Ruiz, Enrico; Madau, Piero; Mayer, Lucio; Guedes, Javiera

      2015-07-01

      We investigate the production sites and the enrichment history of r-process elements in the Galaxy, as traced by the [Eu/Fe] ratio, using the high resolution, cosmological zoom-in simulation “Eris.” At z = 0, Eris represents a close analog to the Milky Way, making it the ideal laboratory to understand the chemical evolution of our Galaxy. Eris formally traces the production of oxygen and iron due to supernovae (SNe) Ia and SNe II. We include in post-processing the production of r-process elements from compact binary mergers. Unlike previous studies, we find that the nucleosynthetic products from compact binary mergers can be incorporated into stars of very low metallicity and at early times, even with a minimum delay time of 100 Myr. This conclusion is relatively insensitive to modest variations in the merger rate, minimum delay time, and the delay time distribution. By implementing a first-order prescription for metal mixing, we can further improve the agreement between our model and the data for the chemical evolution of both [?/Fe] and [Eu/Fe]. We argue that compact binary mergers could be the dominant source of r-process nucleosynthesis in the Galaxy.

    18. The Evolutionarily Conserved Protein LAS1 Is Required for Pre-rRNA Processing at Both Ends of ITS2

      PubMed Central

      Schillewaert, Stéphanie; Wacheul, Ludivine; Lhomme, Frédéric

      2012-01-01

      Ribosome synthesis entails the formation of mature rRNAs from long precursor molecules, following a complex pre-rRNA processing pathway. Why the generation of mature rRNA ends is so complicated is unclear. Nor is it understood how pre-rRNA processing is coordinated at distant sites on pre-rRNA molecules. Here we characterized, in budding yeast and human cells, the evolutionarily conserved protein Las1. We found that, in both species, Las1 is required to process ITS2, which separates the 5.8S and 25S/28S rRNAs. In yeast, Las1 is required for pre-rRNA processing at both ends of ITS2. It is required for Rrp6-dependent formation of the 5.8S rRNA 3? end and for Rat1-dependent formation of the 25S rRNA 5? end. We further show that the Rat1-Rai1 5?-3? exoribonuclease (exoRNase) complex functionally connects processing at both ends of the 5.8S rRNA. We suggest that pre-rRNA processing is coordinated at both ends of 5.8S rRNA and both ends of ITS2, which are brought together by pre-rRNA folding, by an RNA processing complex. Consistently, we note the conspicuous presence of ?7- or 8-nucleotide extensions on both ends of 5.8S rRNA precursors and at the 5? end of pre-25S RNAs suggestive of a protected spacer fragment of similar length. PMID:22083961

    19. Balancing SoNaR: IPR versus Processing Issues in a 500-Million-Word Written Dutch Reference Corpus

      E-print Network

      Theune, Mariët

      Balancing SoNaR: IPR versus Processing Issues in a 500-Million-Word Written Dutch Reference Corpus during the creation of the SoNaR Corpus. Based on recent developments in traditional corpus compiling and new web harvesting approaches, SoNaR is designed to contain 500 million words, balanced over 36 text

    20. Hans A. Bethe Prize: Astrophysical, observational and nuclear-physics aspects of r-process nucleosynthesis

      NASA Astrophysics Data System (ADS)

      Kratz, Karl-Ludwig

      2014-03-01

      Guided by the Solar System (S.S.) abundance peaks at A ~= 130 and A ~= 195, the basic mechanisms for the rapid neutron-capture process (the r-process) have been known for over 50 years. However, even today, all proposed scenarios and sites face problems with astrophysical conditions as well as with the necessary nuclear-physics input. In my talk, I will describe efforts in experimental and theoretical nuclear-structure data for modeling today's three groups of r-process ``observables'', i.e. the bulk S.S. isotopic abundances, the elemental abundances in metal-poor halo stars, and peculiar isotopic patterns measured in certain cosmic stardust grains. To set a historical basis, I will briefly recall our site-independent ``waiting-point'' model, with superpositions of neutron-density components and the use of the first global, unified nuclear input based on the mass model FRDM(1992). This approach provided a considerable leap forward in the basic understanding of the required astrophysical conditions, as well as of specific shell-structure properties far from stability. Starting in the early millenium, the above simple model has been replaced by more realistic, dynamical parameter studies within the high-entropy wind scenario of core-collapse supernovae, now with superpositions of entropy (S) and electron-fraction (Ye) components. Furthermore, an improved, global set of nuclear-physics data is used today, based on the new mass model FRDM(2012). With this nuclear and astrophysics parameter combination, a new fit to the S.S. r-abundances will be shown, and its improvements and remaining deficiencies in terms of underlying shell structure will be discussed. Concerning the abundance patterns in metal-poor halo stars, an interpretation of the production of ``r-rich'' (e.g. CS 22892-052) and ``r-poor'' (e.g. HD 122563) stars in terms of different (Ye), S combinations will be presented. Finally, for the third group of ``r-observables'', a possible origin of the anomalous Xe-H pattern in presolar nanodiamonds by the ``main'' component of a ``cold'' r-process is suggested.

    1. Physics and Process Modeling (PPM) and Other Propulsion R and T. Volume 1; Materials Processing, Characterization, and Modeling; Lifting Models

      NASA Technical Reports Server (NTRS)

      1997-01-01

      This CP contains the extended abstracts and presentation figures of 36 papers presented at the PPM and Other Propulsion R&T Conference. The focus of the research described in these presentations is on materials and structures technologies that are parts of the various projects within the NASA Aeronautics Propulsion Systems Research and Technology Base Program. These projects include Physics and Process Modeling; Smart, Green Engine; Fast, Quiet Engine; High Temperature Engine Materials Program; and Hybrid Hyperspeed Propulsion. Also presented were research results from the Rotorcraft Systems Program and work supported by the NASA Lewis Director's Discretionary Fund. Authors from NASA Lewis Research Center, industry, and universities conducted research in the following areas: material processing, material characterization, modeling, life, applied life models, design techniques, vibration control, mechanical components, and tribology. Key issues, research accomplishments, and future directions are summarized in this publication.

    2. {beta}-delayed neutron emission measurements around the third r-process abundance peak

      SciTech Connect

      Caballero-Folch, R.; Cortes, G.; Calvino, F.; Gomez-Hornillos, M. B.; Riego, A.; Domingo-Pardo, C.; Tain, J. L.; Agramunt, J.; Rubio, B.; Algora, A.; Ameil, F.; Farinon, F.; Heil, M.; Knoebel, R.; Kojouharov, I.; Kurcewicz, J.; Kurz, N.; Litvinov, Y.; Mukha, I.; Nociforo, C.; and others

      2013-06-10

      This contribution summarizes an experiment performed at GSI (Germany) in the neutron-rich region beyond N=126. The aim of this measurement is to provide the nuclear physics input of relevance for r-process model calculations, aiming at a better understanding of the third r-process abundance peak. Many exotic nuclei were measured around {sup 211}Hg and {sup 215}Tl. Final ion identification diagrams are given in this contribution. For most of them, we expect to derive halflives and and {beta}-delayed neutron emission probabilities. The detectors used in this experiment were the Silicon IMplantation and Beta Absorber (SIMBA) detector, based on an array of highly segmented silicon detectors, and the BEta deLayEd Neutron (BELEN) detector, which consisted of 30 3He counters embedded in a polyethylene matrix.

    3. Neutron single particle structure in 131Sn and the r-process

      SciTech Connect

      Kozub, R. L.; Bardayan, Daniel W; Adekola, Aderemi S; Blackmon, Jeff C; Chae, K. Y.; Chipps, K.; Cizewski, J. A.; Erikson, Luke; Hatarik, Robert; Jones, K. L.; Krolas, W.; Liang, J Felix; Ma, Zhanwen; Matei, Catalin; Moazen, Brian; Nesaraja, Caroline D; Pain, Steven D; Shapira, Dan; ShrinerJr., J. F.; Smith, Michael Scott; Swan, T. P.

      2009-01-01

      Recent calculations suggest that, at late times in the r-process, the rate of neutron capture by {sup 130}Sn has a significant impact on nucleosynthesis. Direct capture into low-lying bound states is likely the dominant reaction in the r-process near the N=82 closed shell, so reaction rates are strongly impacted by the properties of neutron single particle states in this region. In order to investigate these properties, we have acquired (d,p) reaction data in the A{approx}132 region in inverse kinematics using {approx}630 MeV beams (4.85 MeV/u for {sup 130}Sn) and CD{sub 2} targets. An array of Si strip detectors, including SIDAR and an early implementation of the new Oak Ridge Rutgers University Barrel Array (ORRUBA), was used to detect reaction products. Preliminary results for the {sup 130}Sn(d,p){sup 131}Sn experiment are reported.

    4. Toward precision mass measurements of neutron-rich nuclei relevant to $r$-process nucleosynthesis

      E-print Network

      B. H. Sun; Yu. A. Litvinov; I. Tanihata; Y. H. Zhang

      2015-08-04

      The open question of where, when, and how the heavy elements beyond iron enrich our Universe has triggered a new era in nuclear physics studies.\\ Of all the relevant nuclear physics inputs, the mass of very neutron-rich nuclides is a key quantity for revealing the origin of heavy elements beyond iron.\\ Although the precise determination of this property is a great challenge, enormous progress has been made in recent decades, and it has contributed significantly to both nuclear structure and astrophysical nucleosynthesis studies.\\ In this review, we first survey our present knowledge of the nuclear mass surface, emphasizing the importance of nuclear mass precision in $r$-process calculations.\\ We then discuss recent progress in various methods of nuclear mass measurement with a few selected examples.\\ For each method, we focus on recent breakthroughs and discuss possible ways of improving the weighing of $r$-process nuclides.

    5. The waiting point approximation in R-process calculations. [of astrophysical nucleosynthesis

      NASA Technical Reports Server (NTRS)

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

      1983-01-01

      The steady flow approximation to the r-process has been used to evaluate the validity of the waiting point assumption (that, for a given charge number Z, neutron captures become balanced by neutron photodisintegrations) under a variety of conditions. The criterion for the accuracy of the approximation for any set of nuclei with the same value of Z is that the ratio of the total rate of neutron photodisintegration in those nuclei to the total rate of neutron captures should be close to unity. No set of conditions involving neutron production by helium thermonuclear reactions (at temperatures up to 10 to the 9th K) could be found for which the waiting point approximation is useful for all values of Z, and it is recommended that all such r-process calculations not use this approximation. At higher temperatures, such as those characteristic of explosive carbon burning (2 x 10 to the 9th K), the waiting point approximation is much better.

    6. Toward precision mass measurements of neutron-rich nuclei relevant to $r$-process nucleosynthesis

      E-print Network

      Sun, B H; Tanihata, I; Zhang, Y H

      2015-01-01

      The open question of where, when, and how the heavy elements beyond iron enrich our Universe has triggered a new era in nuclear physics studies.\\ Of all the relevant nuclear physics inputs, the mass of very neutron-rich nuclides is a key quantity for revealing the origin of heavy elements beyond iron.\\ Although the precise determination of this property is a great challenge, enormous progress has been made in recent decades, and it has contributed significantly to both nuclear structure and astrophysical nucleosynthesis studies.\\ In this review, we first survey our present knowledge of the nuclear mass surface, emphasizing the importance of nuclear mass precision in $r$-process calculations.\\ We then discuss recent progress in various methods of nuclear mass measurement with a few selected examples.\\ For each method, we focus on recent breakthroughs and discuss possible ways of improving the weighing of $r$-process nuclides.

    7. Nuclear data needs for studying the astrophysical r- and p-processes

      SciTech Connect

      Howard, W.M. ); Meyer, B.S. . Dept. of Physics and Astronomy)

      1991-09-01

      Recent advances in understanding the astrophysical sites for the r-, p- and 3-processes has led to an increased understanding of the nuclear physics requires to calculate the thermonuclear origin of the heavy elements in nature. We review specific examples of where nuclear information obtained with Radioactive Nuclear Beams can greatly help our understanding of the thermonuclear origin of the elements in nature. 4 figs.

    8. Phenopix: a R package to process digital images of a vegetation cover

      NASA Astrophysics Data System (ADS)

      Filippa, Gianluca; Cremonese, Edoardo; Migliavacca, Mirco; Galvagno, Marta; Morra di Cella, Umberto; Richardson, Andrew

      2015-04-01

      Plant phenology is a globally recognized indicator of the effects of climate change on the terrestrial biosphere. Accordingly, new tools to automatically track the seasonal development of a vegetation cover are becoming available and more and more deployed. Among them, near-continuous digital images are being collected in several networks in the US, Europe, Asia and Australia in a range of different ecosystems, including agricultural lands, deciduous and evergreen forests, and grasslands. The growing scientific interest in vegetation image analysis highlights the need of easy to use, flexible and standardized processing techniques. In this contribution we illustrate a new open source package called "phenopix" written in R language that allows to process images of a vegetation cover. The main features include: (i) define of one or more areas of interest on an image and process pixel information within them, (ii) compute vegetation indexes based on red green and blue channels, (iii) fit a curve to the seasonal trajectory of vegetation indexes and extract relevant dates (aka thresholds) on the seasonal trajectory; (iv) analyze image pixels separately to extract spatially explicit phenological information. The utilities of the package will be illustrated in detail for two subalpine sites, a grassland and a larch stand at about 2000 m in the Italian Western Alps. The phenopix package is a cost free and easy-to-use tool that allows to process digital images of a vegetation cover in a standardized, flexible and reproducible way. The software is available for download at the R forge web site (r-forge.r-project.org/projects/phenopix/).

    9. Exploiting Pre-rRNA Processing in Diamond Blackfan Anemia Gene Discovery and Diagnosis

      PubMed Central

      Farrar, Jason E.; Quarello, Paola; Fisher, Ross; O’Brien, Kelly A.; Aspesi, Anna; Parrella, Sara; Henson, Adrianna L.; Seidel, Nancy E.; Atsidaftos, Eva; Prakash, Supraja; Bari, Shahla; Garelli, Emanuela; Arceci, Robert J.; Dianzani, Irma; Ramenghi, Ugo; Vlachos, Adrianna; Lipton, Jeffrey M.; Bodine, David M.; Ellis, Steven R.

      2014-01-01

      Diamond Blackfan anemia (DBA), a syndrome primarily characterized by anemia and physical abnormalities, is one among a group of related inherited bone marrow failure syndromes (IBMFS) which share overlapping clinical features. Heterozygous mutations or single-copy deletions have been identified in 12 ribosomal protein genes in approximately 60% of DBA cases, with the genetic etiology unexplained in most remaining patients. Unlike many IBMFS, for which functional screening assays complement clinical and genetic findings, suspected DBA in the absence of typical alterations of the known genes must frequently be diagnosed after exclusion of other IBMFS. We report here a novel deletion in a child that presented such a diagnostic challenge and prompted development of a novel functional assay that can assist in the diagnosis of a significant fraction of patients with DBA. The ribosomal proteins affected in DBA are required for pre-rRNA processing, a process which can be interrogated to monitor steps in the maturation of 40S and 60S ribosomal subunits. In contrast to prior methods used to assess pre-rRNA processing, the assay reported here, based on capillary electrophoresis measurement of the maturation of rRNA in pre-60S ribosomal subunits, would be readily amenable to use in diagnostic laboratories. In addition to utility as a diagnostic tool, we applied this technique to gene discovery in DBA, resulting in the identification of RPL31 as a novel DBA gene. PMID:25042156

    10. Cosmic neutron-star merger rate and gravitational waves constrained by the r-process nucleosynthesis

      NASA Astrophysics Data System (ADS)

      Vangioni, Elisabeth; Goriely, Stéphane; Daigne, Frédéric; François, Patrick; Belczynski, Krzysztof

      2016-01-01

      The cosmic evolution of the neutron-star merger (NSM) rate can be deduced from the observed cosmic star formation rate. This allows us to estimate the rate expected in the horizon of the gravitational wave detectors advanced Virgo and advanced LIGO and to compare those rates with independent predictions. In this context, the rapid neutron-capture process, or r-process, can be used as a constraint assuming NSM is the main astrophysical site for this nucleosynthetic process. We compute the early cosmic evolution of a typical r-process element, europium. Eu yields from NSM are taken from recent nucleosynthesis calculations. The same approach allows us to compute the cosmic rate of Core-Collapse SuperNovae (CCSNe) and the associated evolution of Eu. We find that the bulk of Eu observations at [Fe/H] > -2.5 can be rather well fitted by either CCSN or NSM scenarios. However, at lower metallicity, the early Eu cosmic evolution favours NSM as the main astrophysical site for the r-process. A comparison between our calculations and spectroscopic observations at very low metallicities allows us to constrain the coalescence time-scale in the NSM scenario to ˜0.1-0.2 Gyr. These values are in agreement with the coalescence time-scales of some observed binary pulsars. Finally, the cosmic evolution of Eu is used to put constraints on (i) the NSM rate, (ii) the merger rate in the horizon of the gravitational wave detectors advanced Virgo/ad LIGO, as well as (iii) the expected rate of electromagnetic counterparts to mergers (`kilonovae') in large near-infrared surveys.

    11. Silver and palladium help unveil the nature of a second r-process

      E-print Network

      Hansen, Camilla Juul; Hartman, Henrik; Kratz, Karl-Ludwig; Wanajo, Shinya; Leibundgut, Bruno; Farouqi, Khalil; Hallmann, Oliver; Christlieb, Norbert; Nilsson, Hampus

      2012-01-01

      The rapid neutron-capture process, creating about half of the heaviest elements in the Solar System was believed to be unique. Many recent studies have shown that this does not include the formation of lighter elements (in particular 38 palladium (Pd) and especially silver (Ag) are expected to be key indicators of a possible second r-process, but until recently they have been studied only in a few stars. Therefore we target Pd and Ag in a large sample of stars and compare these abundances to those of Sr, Y, Zr, Ba and Eu produced by the slow (s-) and rapid (r-) neutron-capture processes. Hereby we investigate the nature of the formation process of Ag and Pd. Through a homogeneous 1D LTE analysis of 71 stars we derive stellar abundances using the spectrum synthesis code MOOG, and MARCS model atmospheres. We calculate abundance ratio trends and compare the derived abundances to site-dependent yield predictions (low mass O-Ne-Mg cc SN, and parametrised high entropy winds), to extrac...

    12. The r-process Nucleosynthesis in the Various Jet-like Explosions of Magnetorotational Core-collapse Supernovae

      NASA Astrophysics Data System (ADS)

      Nishimura, Nobuya; Takiwaki, Tomoya; Thielemann, Friedrich-Karl

      2015-09-01

      The r-process nucleosynthesis in core-collapse supernovae (CC-SNe) is studied, with a focus on the explosion scenario induced by rotation and strong magnetic fields. Nucleosynthesis calculations are conducted based on magneto-hydrodynamical explosion models with a wide range of parameters for initial rotation and magnetic fields. The explosion models are classified in two different types: prompt-magnetic-jet and delayed-magnetic-jet, for which the magnetic fields of proto-neutron stars (PNSs) during collapse and the core-bounce are strong and comparatively moderate, respectively. Following the hydrodynamical trajectories of each explosion model, we confirmed that r-processes successfully occur in the prompt-magnetic-jets, which produce heavy nuclei including actinides. On the other hand, the r-process in the delayed-magnetic-jet is suppressed, which synthesizes only nuclei up to the second peak (A? 130). Thus, the r-process in the delayed-magnetic-jets could explain only “weak r-process” patterns observed in metal-poor stars rather than the “main r-process,” represented by the solar abundances. Our results imply that CC-SNe are possible astronomical sources of heavy r-process elements if their magnetic fields are strong enough, while weaker magnetic explosions may produce “weak r-process” patterns (A? 130). We show the potential importance and necessity of magneto-rotational SNe for explaining the galactic chemical evolution, as well as abundances of r-process enhanced metal-poor stars. We also examine the effects of the remaining uncertainties in the nature of PNSs due to weak interactions that determine the final neutron-richness of ejecta. Additionally, we briefly discuss radioactive isotope yields in primary jets (e.g., 56Ni), with relation to several optical observation of SNe and relevant high-energy astronomical phenomena.

    13. R/V Kilo Moana's New Geophysical Instrumentation, Processing Methods, and Online Data Repository

      NASA Astrophysics Data System (ADS)

      Miller, J. E.; Chandler, M. T.; Taylor, B.; Shor, A.; Ferguson, J. S.; Wessel, P.

      2012-12-01

      In 2012 several upgrades were made to the underway geophysical systems on R/V Kilo Moana, which the University of Hawaii School of Ocean and Earth Science and Technology (SOEST) operates as part of the University-National Oceanographic Laboratory System (UNOLS) fleet. New instrumentation includes a Bell BGM-3 forced feedback-type gravimeter, a Kongsberg EM 122 12-kHz receiver array, and a high resolution 70-100 kHz EM 710 multibeam echo sounder. Multibeam acceptance trials carried out in June by the Multibeam Advisory Committee, Gates Acoustic Services and UH-SOEST found that both sonars are performing within expected levels with ~5x water depth (WD) for the EM 710 system in shallow water and ~19 km swath width at 4,700 m depth (~4x WD) for the EM 122 deep water system. UH-SOEST also took steps this year to fulfill its obligation to make Kilo Moana's geophysical data more accessible to the public. After an audit of Kilo Moana data at SOEST, Lamont's Rolling Deck to Repository (R2R) and the National Geophysical Data Center (NGDC), as of July 2012 all National Science Foundation-funded Kilo Moana multibeam, gravity, magnetics, center beam depth and Acoustic Doppler Current Profiler (ADCP) data have been submitted to R2R and any multibeam data over 2 years old is being transferred to NGDC. Because it had previously been difficult to access some of SOEST's geophysical data, updated data processing routines have been developed for converting raw gravity, magnetics, and centerbeam depth data to NGDC's standard marine data exchange format (MGD77) for archival and dissemination by NGDC. MGD77 files are being generated and inspected using rigorous along-track analytical techniques for ~270 surveys dating from 2002 to the present and are being submitted to NGDC. We are also developing an online data portal to further facilitate access to SOEST data.

    14. Puzzling Origin of CEMP-r/s Stars: An Interpretation of Abundance and Enrichment of s- and r-Process Elements from Asymptotic Giant Branch Supernovae

      NASA Astrophysics Data System (ADS)

      Zhang, Jiang; Zhao, Fang; Chen, Yanping; Cui, Wenyuan; Zhang, Bo

      2013-12-01

      CEMP-r/s stars at low metallicity are known as double-enhanced stars that show enhancements of both r-process and s-process elements. The chemical abundances of these very metal-poor stars provide us a lot of information for putting new restraints on models of neutron-capture processes. In this article, we put forward an accreted scenario in which the double enrichment of r-process and s-process elements is caused by a former intermediate-mass Asymptotic Giant Branch (AGB) companion in a detached binary system. As the AGB superwind is only present at the ultimate phase of AGB stars, there is thus a lot of potential that the degenerate-core mass of an intermediate-mass AGB star reaches the Chandrasekhar limit before the AGB superwind. In these circumstances, both s-process elements produced in the AGB shell and r-process elements synthesized in the subsequent explosion would be sprayed contemporaneously and accreted by its companion. Despite similarity to physical conditions of a core-collapse supernova, a major focus in this scenario is the degenerate C-O core surrounded by an envelope of a former intermediate-mass AGB donor that may collapse and explode. Due to the existence of an outer envelope, r-process nucleosynthesis is expected to occur. Hypothesizing the material-rich europium (Eu) accreted by the secondary via the wind from the supernova to be in proportion to the geometric fraction of the companion with respect to the exploding donor star, we find that the estimated yield of Eu (as representative of r-process elements) per AGB supernova event is about 1 × 10-9 M ? ˜ 5 × 10-9 M ?. Using the yields of Eu, the overabundance of r-process elements in CEMP-r/s stars can be accounted for. The calculated results show that the value of parameter f , standing for efficiency of wind pollution from the AGB supernova, will reach about 104, which means that the enhanced factor is much larger than unity due to the impact of gravity of the donor and the result of the gravitational focusing effect of the companion.

    15. Single Neutron Transfer Experiments Close to the r-Process Path

      SciTech Connect

      Grzywacz-Jones, Kate L; Adekola, Aderemi S; Bardayan, Daniel W; Blackmon, Jeff C; Chae, Kyung Yuk; Chipps, K.; Cizewski, Jolie; Dean, David Jarvis; Erikson, Luke; Fitzgerald, R. P.; Gaddis, A. L.; Greife, U.; Harlin, Christopher W; Hatarik, Robert; Howard, Joshua A; Johnson, Micah; Kozub, R. L.; Liang, J Felix; Livesay, Jake; Ma, Zhanwen; Moazen, Brian; O'Malley, Patrick; Nesaraja, Caroline D; Pain, S. D.; Patterson, N. P.; Paulauskas, Stanley V; Shapira, Dan; ShrinerJr., J. F.; Sissom, D. J.; Smith, Michael Scott; Swan, T. P.; Thomas, J. S.

      2007-01-01

      The first measurements using the (d, p) transfer reaction to study single- particle states in nuclei on the expected r-process path have been made at the Holifield Radioactive Ion Beam Facility. The shell closure at N = 50 has been crossed using the 82Ge(d, p) and 84Se(d, p) reactions. The prop- erties of the lowest-lying states have been determined. Furthermore, the 132Sn(d, p) reaction has been used for the first time to populate single- particle states in 133Sn.

    16. Re-187, recycling r-process elements through stars, and the age of the Galaxy.

      NASA Technical Reports Server (NTRS)

      Talbot, R. J., Jr.

      1973-01-01

      The enhanced beta-decay rate of ionized Re-187 in stars has been studied within the context of a detailed numerical model of the production of r-process elements and their recycling through stars during the course of galactic evolution. It is concluded that the enhanced decay rate does not significantly reduce the Re-Os chronometer age for the Galaxy. Consequently, the Re-187 beta-decay half-life and the Os-186/Os-187 neutron cross-section ratio remain as the significant uncertainties in this chronology. Unlike the uncertainties in other chronologies, both are amenable to laboratory measurements.

    17. Half-lives of N = 126 Isotones and the r-Process

      SciTech Connect

      Suzuki, Toshio; Yoshida, Takashi; Utsuno, Yutaka

      2010-08-12

      Beta decays of N = 126 isotones are studied by shell model calculations. Both the Gamow-Teller (GT) and first-forbidden (FF) transitions are taken into account to evaluate the half-lives of the isotones (Z = 64-72) with the use of shell model interactions based on G-matrix. The FF transitions are found to be important to reduce the half-lives by twice to several times of those obtained by the GT contributions only. Possible implications of the short half-lives of the waiting point nuclei on the r-process nucleosynthesis during the supernova explosions are discussed.

    18. THE ORIGINS OF LIGHT AND HEAVY R-PROCESS ELEMENTS IDENTIFIED BY CHEMICAL TAGGING OF METAL-POOR STARS

      SciTech Connect

      Tsujimoto, Takuji; Shigeyama, Toshikazu

      2014-11-01

      Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration ?-ray burst. The hypothesis of a NS merger origin is reinforced by a theoretical update of nucleosynthesis in NS mergers successful in yielding r-process nuclides with A > 130. On the other hand, whether the origin of light r-process elements are associated with nucleosynthesis in NS merger events remains unclear. We find a signature of nucleosynthesis in NS mergers from peculiar chemical abundances of stars belonging to the Galactic globular cluster M15. This finding combined with the recent nucleosynthesis results implies a potential diversity of nucleosynthesis in NS mergers. Based on these considerations, we are successful in the interpretation of an observed correlation between [light r-process/Eu] and [Eu/Fe] among Galactic halo stars and accordingly narrow down the role of supernova nucleosynthesis in the r-process production site. We conclude that the tight correlation by a large fraction of halo stars is attributable to the fact that core-collapse supernovae produce light r-process elements while heavy r-process elements such as Eu and Ba are produced by NS mergers. On the other hand, stars in the outlier, composed of r-enhanced stars ([Eu/Fe] ? +1) such as CS22892-052, were exclusively enriched by matter ejected by a subclass of NS mergers that is inclined to be massive and consist of both light and heavy r-process nuclides.

    19. Delayed rRNA Processing Results in Significant Ribosome Biogenesis and Functional Defects

      PubMed Central

      Meskauskas, Arturas; Baxter, Jennifer L.; Carr, Edward A.; Yasenchak, Jason; Gallagher, Jennifer E. G.; Baserga, Susan J.; Dinman, Jonathan D.

      2003-01-01

      mof6-1 was originally isolated as a recessive mutation in Saccharomyces cerevisiae which promoted increased efficiencies of programmed ?1 ribosomal frameshifting and rendered cells unable to maintain the killer virus. Here, we demonstrate that mof6-1 is a unique allele of the histone deacetylase RPD3, that the deacetylase function of Rpd3p is required for controlling wild-type levels of frameshifting and virus maintenance, and that the closest human homolog can fully complement these defects. Loss of the Rpd3p-associated histone deacetylase function, either by mutants of rpd3 or loss of the associated gene product Sin3p or Sap30p, results in a delay in rRNA processing rather than in an rRNA transcriptional defect. This results in production of ribosomes having lower affinities for aminoacyl-tRNA and diminished peptidyltransferase activities. We hypothesize that decreased rates of peptidyl transfer allow ribosomes with both A and P sites occupied by tRNAs to pause for longer periods of time at ?1 frameshift signals, promoting increased programmed ?1 ribosomal frameshifting efficiencies and subsequent loss of the killer virus. The frameshifting defect is accentuated when the demand for ribosomes is highest, suggesting that rRNA posttranscriptional modification is the bottleneck in ribosome biogenesis. PMID:12588980

    20. New calculations of gross ?-decay properties for astrophysical applications: Speeding-up the classical r process

      NASA Astrophysics Data System (ADS)

      Möller, Peter; Pfeiffer, Bernd; Kratz, Karl-Ludwig

      2003-05-01

      Recent compilations of experimental gross ?-decay properties, i.e., half-lives (T1/2) and neutron-emission probabilities (Pn), are compared to improved global macroscopic-microscopic model predictions. The model combines calculations within the quasiparticle (QP) random-phase approximation for the Gamow-Teller (GT) part with an empirical spreading of the QP strength and the gross theory for the first-forbidden part of ?- decay. Nuclear masses are either taken from the 1995 data compilation of Audi et al., when available, otherwise from the finite-range droplet model. Especially for spherical and neutron-(sub-)magic isotopes a considerable improvement compared to our earlier predictions for pure GT decay (ADNDT, 1997) is observed. T1/2 and Pn values up to the neutron drip line have been used in r-process calculations within the classical “waiting-point” approximation. With the new nuclear-physics input, a considerable speeding-up of the r-matter flow is observed, in particular at those r-abundance peaks which are related to magic neutron-shell closures.

    1. rTMS neuromodulation improves electrocortical functional measures of information processing and behavioral responses in autism

      PubMed Central

      Sokhadze, Estate M.; El-Baz, Ayman S.; Sears, Lonnie L.; Opris, Ioan; Casanova, Manuel F.

      2014-01-01

      Objectives: Reports in autism spectrum disorders (ASD) of a minicolumnopathy with consequent deficits of lateral inhibition help explain observed behavioral and executive dysfunctions. We propose that neuromodulation based on low frequency repetitive Transcranial Magnetic Stimulation (rTMS) will enhance lateral inhibition through activation of inhibitory double bouquet interneurons and will be accompanied by improvements in the prefrontal executive functions. In addition we proposed that rTMS will improve cortical excitation/inhibition ratio and result in changes manifested in event-related potential (ERP) recorded during cognitive tests. Materials and Methods: Along with traditional clinical behavioral evaluations the current study used ERPs in a visual oddball task with illusory figures. We compared clinical, behavioral and electrocortical outcomes in two groups of children with autism (TMS, wait-list group). We predicted that 18 session long course in autistic patients will have better behavioral and ERP outcomes as compared to age- and IQ-matched WTL group. We used 18 sessions of 1 Hz rTMS applied over the dorso-lateral prefrontal cortex in 27 individuals with ASD diagnosis. The WTL group was comprised of 27 age-matched subjects with ASD tested twice. Both TMS and WTL groups were assessed at the baseline and after completion of 18 weekly sessions of rTMS (or wait period) using clinical behavioral questionnaires and during performance on visual oddball task with Kanizsa illusory figures. Results: Post-TMS evaluations showed decreased irritability and hyperactivity on the Aberrant Behavior Checklist (ABC), and decreased stereotypic behaviors on the Repetitive Behavior Scale (RBS-R). Following rTMS course we found decreased amplitude and prolonged latency in the frontal and fronto-central N100, N200 and P300 (P3a) ERPs to non-targets in active TMS treatment group. TMS resulted in increase of P2d (P2a to targets minus P2a to non-targets) amplitude. These ERP changes along with increased centro-parietal P100 and P300 (P3b) to targets are indicative of more efficient processing of information post-TMS treatment. Another important finding was decrease of the latency and increase of negativity of error-related negativity (ERN) during commission errors that may reflect improvement in error monitoring and correction function. Enhanced information processing was also manifested in lower error rate. In addition we calculated normative post-error treaction time (RT) slowing response in both groups and found that rTMS treatment was accompanied by post-error RT slowing and higher accuracy of responses, whereas the WTL group kept on showing typical for ASD post-error RT speeding and higher commission and omission error rates. Conclusion: Results from our study indicate that rTMS improves executive functioning in ASD as evidenced by normalization of ERP responses and behavioral reactions (RT, accuracy) during executive function test, and also by improvements in clinical evaluations. PMID:25147508

    2. J.R. Simplot: Burner Upgrade Project Improves Performance and Saves Energy at a Large Food Processing Plant (Steam)

      SciTech Connect

      2005-09-01

      This DOE Industrial Program case study describes how the J.R. Simplot Company saved energy and money by increasing the efficiency of the steam system in its potato processing plant in Caldwell, Idaho.

    3. J.R. Simplot: Burner Upgrade Project Improves Performance and Saves Energy at a Large Food Processing Plant

      SciTech Connect

      Not Available

      2005-09-01

      This DOE Industrial Program case study describes how the J.R. Simplot Company saved energy and money by increasing the efficiency of the steam system in its potato processing plant in Caldwell, Idaho.

    4. The r-process nucleosynthesis: a continued challenge for nuclear physics and astrophysics

      NASA Astrophysics Data System (ADS)

      Goriely, S.; Demetriou, P.; Janka, H.-Th.; Pearson, J. M.; Samyn, M.

      2005-07-01

      The identification of the astrophysical site and the specific conditions in which r-process nucleosynthesis takes place remain unsolved mysteries of astrophysics. The present paper emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the radiative neutron capture rates by exotic nuclei close to the neutron drip line and the fission probabilities of heavy neutron-rich nuclei. These quantities are particularly relevant to determine the composition of the matter resulting from the decompression of initially cold neutron star matter. New detailed r-process calculations are performed and the final composition of ejected inner and outer neutron star crust material is estimated. We discuss the impact of the many uncertainties in the astrophysics and nuclear physics on the final composition of the ejected matter. The similarity between the predicted and the solar abundance pattern for A?140 nuclei as well as the robustness of the prediction with varied input parameters makes this scenario one of the most promising that deserves further exploration.

    5. Precision mass measurements of neutron-rich nuclei, and limitations on the r-process environment

      NASA Astrophysics Data System (ADS)

      Van Schelt, Jonathon A.

      2012-05-01

      The masses of 65 neutron-rich nuclides and 6 metastable states from Z = 49 to 64 were measured at a typical precision of ?m/m= 10-7 using the Canadian Penning Trap mass spectrometer at Argonne National Laboratory. The measurements are on fission fragments from 252Cf spontaneous fission sources, including those measurements made at the new Californium Rare Isotope Breeder Upgrade facility (CARIBU) and an earlier source. The measured nuclides lie on or approach the predicted path of the astrophysical r process. Where overlap exists, this data set is largely consistent with previous measurements from Penning traps, storage rings, and reaction energetics, but large systematic deviations are apparent in ?-endpoint measurements. Simulations of the r process were undertaken to determine how quickly material can pass through the studied elements for a variety of conditions, placing limits on what temperatures densities allow passage on a desired timescale. The new masses produce manifold differences in effective lifetime compared to simulations performed with some model masses.

    6. Theoretical neutron-capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region

      E-print Network

      Rauscher, T; Kratz, K -L; Balogh, W; Oberhummer, H

      2015-01-01

      We calculate neutron capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region, namely for the isotopes $^{40-44}$S, $^{46-50}$Ar, $^{56-66}$Ti, $^{62-68}$Cr, and $^{72-76}$Fe. While previously only cross sections resulting from the compound nucleus reaction mechanism (Hauser-Feshbach) have been considered, we recalculate not only that contribution to the cross section but also include direct capture on even-even nuclei. The level schemes, which are of utmost importance in the direct capture calculations, are taken from quasi-particle states obtained with a folded-Yukawa potential and Lipkin-Nogami pairing. Most recent deformation values derived from experimental data on $\\beta$-decay half lives are used where available. Due to the consideration of direct capture, the capture rates are enhanced and the "turning points" in the r-process path are shifted to slightly higher mass numbers. We also discuss the sensitivity of the direct capture cross sections on the assumed deformation.

    7. Parameter study of r-process lanthanide production and heating rates in kilonovae

      NASA Astrophysics Data System (ADS)

      Lippuner, Jonas; Roberts, Luke F.

      2015-04-01

      Explosive r-process nucleosynthesis in material ejected during compact object mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients are sensitive to the composition of the material after nuclear burning ceases, as the composition determines the local heating rate from nuclear decays and the opacity. The presence of lanthanides in the ejecta can drastically increase the opacity. We use the new general-purpose nuclear reaction network SkyNet to run a parameter study of r-process nucleosynthesis for a range of initial electron fractions Ye, initial entropies s, and density decay timescales ?. We find that the ejecta is lanthanide-free for Ye >~ 0 . 22 - 0 . 3 , depending on s and ?. The heating rate is insensitive to s and ?, but certain, larger values of Ye lead to reduced heating rates, because single nuclides dominate the heating. With a simple model we estimate the luminosity, time, and effective temperature at the peak of the light curve. Since the opacity is much lower in the lanthanide-free case, we find the luminosity peaks much earlier at ~ 1 day vs. ~ 15 days in the lanthanide-rich cases. Although there is significant variation in the heating rate with Ye, changes in the heating rate do not mitigate the effect of the lanthanides. This research is partially supported by NSF under Award Numbers AST-1333520 and AST-1205732.

    8. Chemical evolution of r-process elements in Draco dwarf spheroidal galaxies

      NASA Astrophysics Data System (ADS)

      Nitta Ishigaki, Miho; Tsujimoto, Takuji; Shigeyama, Toshikazu; Aoki, Wako

      2015-08-01

      Dwarf galaxies around the Milky Way halo are ideal laboratory of nucleosynthesis and chemical enrichments in the early universe. We studied chemical compositions including r-process elements for giant stars in Draco dwarf spheroidal galaxy based on high-resolution spectra obtained with the Subaru/HDS. Draco is known to mainly consist of old (age > 10 Gyr) and metal-poor ([Fe/H]<-1.5) stellar populations, which provides us an important insights about nucleosynthesis responsible for producing heavy elements in this galaxy. As reported in previous studies, we found that the Draco stars show enhanced [?/Fe] ratios at [Fe/H]<-2, decreasing at higher metallicity. This is consistent with an expectation that the chemical evolution is proceeded in a homogeneous manner initially by Type II and later by Type Ia supernovae. On the other hand, the [Eu/H] are constant over the metallicity range -2<[Fe/H]<-1 and low upper limits have been obtained at the lower [Fe/H]. The lack of increase in Eu abundance, despite the significant increase in Fe abundance by supernovae, implies that r-process elements were produced through much rarer events such as neutron-star mergers.

    9. Theoretical neutron-capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region

      E-print Network

      T. Rauscher; W. Böhmer; K. -L. Kratz; W. Balogh; H. Oberhummer

      2015-04-17

      We calculate neutron capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region, namely for the isotopes $^{40-44}$S, $^{46-50}$Ar, $^{56-66}$Ti, $^{62-68}$Cr, and $^{72-76}$Fe. While previously only cross sections resulting from the compound nucleus reaction mechanism (Hauser-Feshbach) have been considered, we recalculate not only that contribution to the cross section but also include direct capture on even-even nuclei. The level schemes, which are of utmost importance in the direct capture calculations, are taken from quasi-particle states obtained with a folded-Yukawa potential and Lipkin-Nogami pairing. Most recent deformation values derived from experimental data on $\\beta$-decay half lives are used where available. Due to the consideration of direct capture, the capture rates are enhanced and the "turning points" in the r-process path are shifted to slightly higher mass numbers. We also discuss the sensitivity of the direct capture cross sections on the assumed deformation.

    10. Possible discovery of the r-process characteristics in the abundances of metal-rich barium stars

      E-print Network

      Cui, W Y; Shi, J R; Zhao, G; Wang, W J; Niu, P

      2014-01-01

      We study the abundance distributions of a sample of metal-rich barium stars provided by Pereira et al. (2011) to investigate the s- and r-process nucleosynthesis in the metal-rich environment. We compared the theoretical results predicted by a parametric model with the observed abundances of the metal-rich barium stars. We found that six barium stars have a significant r-process characteristic, and we divided the barium stars into two groups: the r-rich barium stars ($C_r>5.0$, [La/Nd]\\,$barium stars. The behavior of the r-rich barium stars seems more like that of the metal-poor r-rich and CEMP-r/s stars. We suggest that the most possible formation mechanism for these stars is the s-process pollution, although their abundance patterns can be fitted very well when the pre-enrichment hypothesis is included. The fact that we can not explain them well using the s-process nucleosynthesis alone may be due to our incomplete knowledge on the production of Nd, Eu, and other relevant elements by the ...

    11. Galactic r-process enrichment by neutron star mergers in cosmological simulations of a Milky Way-mass galaxy

      NASA Astrophysics Data System (ADS)

      van de Voort, Freeke; Quataert, Eliot; Hopkins, Philip F.; Kereš, Dušan; Faucher-Giguère, Claude-André

      2015-02-01

      We quantify the stellar abundances of neutron-rich r-process nuclei in cosmological zoom-in simulations of a Milky Way-mass galaxy from the Feedback In Realistic Environments project. The galaxy is enriched with r-process elements by binary neutron star (NS) mergers and with iron and other metals by supernovae. These calculations include key hydrodynamic mixing processes not present in standard semi-analytic chemical evolution models, such as galactic winds and hydrodynamic flows associated with structure formation. We explore a range of models for the rate and delay time of NS mergers, intended to roughly bracket the wide range of models consistent with current observational constraints. We show that NS mergers can produce [r-process/Fe] abundance ratios and scatter that appear reasonably consistent with observational constraints. At low metallicity, [Fe/H] ? -2, we predict there is a wide range of stellar r-process abundance ratios, with both supersolar and subsolar abundances. Low-metallicity stars or stars that are outliers in their r-process abundance ratios are, on average, formed at high redshift and located at large galactocentric radius. Because NS mergers are rare, our results are not fully converged with respect to resolution, particularly at low metallicity. However, the uncertain rate and delay time distribution of NS mergers introduce an uncertainty in the r-process abundances comparable to that due to finite numerical resolution. Overall, our results are consistent with NS mergers being the source of most of the r-process nuclei in the Universe.

    12. Process R&D for CIS-Based Thin-Film PV: Final Technical Report, April 2002 - April 2005

      SciTech Connect

      Tarrant, D. E.; Gay, R. R.

      2006-01-01

      The primary objectives of this Shell Solar Industries subcontract are to address key near-term technical R&D issues for continued CIS product improvement; continue process development for increased production capacity; develop processes capable of significantly contributing to DOE 2020 PV shipment goals; advance mid- and longer-term R&D needed by industry for future product competitiveness including improving module performance, decreasing production process costs per watt produced, and improving reliability; and perform aggressive module lifetime R&D directed at developing packages that address the DOE goal for modules that will last up to 30 years while retaining 80% of initial power. These production R&D results, production volume, efficiency, high line yield, and advances in understanding are major accomplishments. The demonstrated and maintained high production yield is a major accomplishment supporting attractive cost projections for CIS. Process R&D at successive levels of CIS production has led to the continued demonstration of the prerequisites for commitment to large-scale commercialization. Process and packaging R&D during this and previous subcontracts has demonstrated the potential for further cost and performance improvements.

    13. Ribosome biogenesis requires a highly diverged XRN family 5'->3' exoribonuclease for rRNA processing in Trypanosoma brucei.

      PubMed

      Sakyiama, Joseph; Zimmer, Sara L; Ciganda, Martin; Williams, Noreen; Read, Laurie K

      2013-10-01

      Although biogenesis of ribosomes is a crucial process in all organisms and is thus well conserved, Trypanosoma brucei ribosome biogenesis, of which maturation of rRNAs is an early step, has multiple points of divergence. Our aim was to determine whether in the processing of the pre-rRNA precursor molecule, 5'?3' exoribonuclease activity in addition to endonucleolytic cleavage is necessary in T. brucei as in other organisms. Our approach initiated with the bioinformatic identification of a putative 5'?3' exoribonuclease, XRNE, which is highly diverged from the XRN2/Rat1 enzyme responsible for rRNA processing in other organisms. Tagging this protein in vivo allowed us to classify XRNE as nucleolar by indirect immunofluorescence and identify by copurification interacting proteins, many of which were ribosomal proteins, ribosome biogenesis proteins, and/or RNA processing proteins. To determine whether XRNE plays a role in ribosome biogenesis in procyclic form cells, we inducibly depleted the protein by RNA interference. This resulted in the generation of aberrant preprocessed 18S rRNA and 5' extended 5.8S rRNA, implicating XRNE in rRNA processing. Polysome profiles of XRNE-depleted cells demonstrated abnormal features including an increase in ribosome small subunit abundance, a decrease in large subunit abundance, and defects in polysome assembly. Furthermore, the 5' extended 5.8S rRNA in XRNE-depleted cells was observed in the large subunit, monosomes, and polysomes in this gradient. Therefore, the function of XRNE in rRNA processing, presumably due to exonucleolytic activity very early in ribosome biogenesis, has consequences that persist throughout all biogenesis stages. PMID:23974437

    14. ?-decay spectroscopy of r-process nuclei with N = 126 at KISS

      SciTech Connect

      Hirayama, Y.; Watanabe, Y. X.; Imai, N.; Ishiyama, H.; Jeong, S. C.; Miyatake, H.; Oyaizu, M.; Kim, Y. H.; Mukai, M.; Kimura, S.

      2014-05-02

      The ?-decay properties of nuclei with N = 126, which are believed to act as progenitors in the rapid neutron capture (r-) process path forming the third peak (A ? 195) in the observed r-abundance element distribution, are considered critical for understanding the production of heavy elements such as gold and platinum at astrophysical sites. We have constructed the KEK Isotope Separation System (KISS), which consists of a gas cell based laser ion source (atomic number selection) and an isotope separation on-line (ISOL) (mass number selection), to produce pure low-energy beams of neutron-rich isotopes around N = 126 and to study their ?-decay properties, which are also of interest for astrophysics. The isotopes of interest will be produced by multi-nucleon transfer reactions in heavy ion collisions (e.g. {sup 136}Xe projectile on {sup 198}Pt target). KISS will allow us to study unknown isotopes produced in weak reaction channels under low background conditions. We successfully extracted the stable {sup 56}Fe beam from KISS at the last commissioning on-line experiment with the extraction efficiency of 0.25% and beam purity of more than 98%. We can access the nuclei with N = 126 and measure their half-lives using the KISS in the case of the extraction efficiency of 0.1%.

    15. New Fission Fragment Distributions and r-Process Origin of the Rare-Earth Elements

      NASA Astrophysics Data System (ADS)

      Goriely, S.; Sida, J.-L.; Lemaître, J.-F.; Panebianco, S.; Dubray, N.; Hilaire, S.; Bauswein, A.; Janka, H.-T.

      2013-12-01

      Neutron star (NS) merger ejecta offer a viable site for the production of heavy r-process elements with nuclear mass numbers A?140. The crucial role of fission recycling is responsible for the robustness of this site against many astrophysical uncertainties, but calculations sensitively depend on nuclear physics. In particular, the fission fragment yields determine the creation of 110?A?170 nuclei. Here, we apply a new scission-point model, called SPY, to derive the fission fragment distribution (FFD) of all relevant neutron-rich, fissioning nuclei. The model predicts a doubly asymmetric FFD in the abundant A?278 mass region that is responsible for the final recycling of the fissioning material. Using ejecta conditions based on relativistic NS merger calculations, we show that this specific FFD leads to a production of the A?165 rare-earth peak that is nicely compatible with the abundance patterns in the Sun and metal-poor stars. This new finding further strengthens the case of NS mergers as possible dominant origin of r nuclei with A?140.

    16. New fission fragment distributions and r-process origin of the rare-earth elements.

      PubMed

      Goriely, S; Sida, J-L; Lemaître, J-F; Panebianco, S; Dubray, N; Hilaire, S; Bauswein, A; Janka, H-T

      2013-12-13

      Neutron star (NS) merger ejecta offer a viable site for the production of heavy r-process elements with nuclear mass numbers A?140. The crucial role of fission recycling is responsible for the robustness of this site against many astrophysical uncertainties, but calculations sensitively depend on nuclear physics. In particular, the fission fragment yields determine the creation of 110?A?170 nuclei. Here, we apply a new scission-point model, called SPY, to derive the fission fragment distribution (FFD) of all relevant neutron-rich, fissioning nuclei. The model predicts a doubly asymmetric FFD in the abundant A?278 mass region that is responsible for the final recycling of the fissioning material. Using ejecta conditions based on relativistic NS merger calculations, we show that this specific FFD leads to a production of the A?165 rare-earth peak that is nicely compatible with the abundance patterns in the Sun and metal-poor stars. This new finding further strengthens the case of NS mergers as possible dominant origin of r nuclei with A?140. PMID:24483647

    17. Mass measurements near the $r$-process path using the Canadian Penning Trap mass spectrometer

      E-print Network

      Van Schelt, J; Savard, G; Clark, J A; Caldwell, S; Chaudhuri, A; Fallis, J; Greene, J P; Levand, A F; Li, G; Sharma, K S; Sternberg, M G; Sun, T; Zabransky, B J

      2012-01-01

      The masses of 40 neutron-rich nuclides from Z = 51 to 64 were measured at an average precision of $\\delta m/m= 10^{-7}$ using the Canadian Penning Trap mass spectrometer at Argonne National Laboratory. The measurements, of fission fragments from a $^{252}$Cf spontaneous fission source in a helium gas catcher, approach the predicted path of the astrophysical $r$ process. Where overlap exists, this data set is largely consistent with previous measurements from Penning traps, storage rings, and reaction energetics, but large systematic deviations are apparent in $\\beta$-endpoint measurements. Differences in mass excess from the 2003 Atomic Mass Evaluation of up to 400 keV are seen, as well as systematic disagreement with various mass models.

    18. R-matrix Floquet theory of multiphoton processes: XIII. Resonances in ? multiphoton detachment

      NASA Astrophysics Data System (ADS)

      van der Hart, H. W.; Fearnside, A. S.

      1997-12-01

      The results of calculations investigating the effects of autodetaching resonances on the multiphoton detachment spectra of 0953-4075/30/24/007/img6 are presented. The R-matrix Floquet method is used, in which the coupling of the ion with the laser field is described non-perturbatively. The laser field is fixed at an intensity of 0953-4075/30/24/007/img7, while frequency ranges are chosen such that the lowest autodetaching states of the ion are excited through a two- or three-photon transition from the ground state. Detachment rates are compared, where possible, to previous results obtained using perturbation theory. An illustration of how non-lowest-order processes, involving autodetaching states, can lead to light-induced continuum structures is also presented. Finally, it is demonstrated that by using a frequency connecting the 1s and 2s states, the probability of exciting the residual hydrogen atom is significantly enhanced.

    19. Precision Mass Measurements of Short-Lived, Neutron-Rich, R-Process Nuclei About the N=82 Waiting Point

      NASA Astrophysics Data System (ADS)

      Lascar, Daniel David

      This thesis details the precision mass measurements of 33 neutron-rich ground-state nuclei and isomeric states that approach or lie on the proposed rapid neutron capture process (r-process) path. For many of the nuclei measured the work presented here will be the rst direct mass measurements of these nuclei, including 130In, 137Sb, 133I, and 134I. The measurements were made using the Canadian Penning Trap mass spectrometer (CPT), located at the ATLAS heavy ion-linac at Argonne National Laboratory. Ground states and isomers have been measured with the CPT at fractional precisions (?m/m) between 10-7, and 10-8. The nuclei were produced at the new CAlifornium Rare Isotope Breeder Upgrade (CARIBU) to ATLAS. Because nuclear masses are required for measuring neutron separation energies, and neutron separation energies are important inputs in r-process network calculations, precision mass measurements are critical for advancing our knowledge of the r-process. This thesis will give the astrophysical motivation for making these mass measurements, the theoretical background behind ion trapping and mass measurements using ion traps, an explanation of the CPT apparatus, the mass measurements themselves, and the results of those measurements as they pertain to r-process network calculations. Results of these mass measurements show significant shifts in the r-process path over a range of temperatures and neutron densities.

    20. Julian, B.R. and G.R. Foulger, Monitoring Geothermal Processes with Microearthquake Mechanisms, Thirty-Fourth Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California, February 9-

      E-print Network

      Foulger, G. R.

      Julian, B.R. and G.R. Foulger, Monitoring Geothermal Processes with Microearthquake Mechanisms, Thirty- Fourth Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California, February 9- 11, 2009. Monitoring Geothermal Processes with Microearthquake Mechanisms Bruce R. Julian, U. S

    1. Impact of weak interactions of free nucleons on the r-process in dynamical ejecta from neutron-star mergers

      E-print Network

      Stephane Goriely; Andreas Bauswein; Oliver Just; Else Pllumbi; Hans-Thomas Janka

      2015-04-16

      We investigate beta-interactions of free nucleons and their impact on the electron fraction (Y_e) and r-process nucleosynthesis in ejecta characteristic of binary neutron star mergers (BNSMs). For that we employ trajectories from a relativistic BNSM model to represent the density-temperature evolutions in our parametric study. In the high-density environment, positron captures decrease the neutron richness at the high temperatures predicted by the hydrodynamic simulation. Circumventing the complexities of modelling three-dimensional neutrino transport, (anti)neutrino captures are parameterized in terms of prescribed neutrino luminosities and mean energies, guided by published results and assumed as constant in time. Depending sensitively on the adopted neutrino-antineutrino luminosity ratio, neutrino processes increase Y_e to values between 0.25 and 0.40, still allowing for a successful r-process compatible with the observed solar abundance distribution and a significant fraction of the ejecta consisting of r-process nuclei. If the electron neutrino luminosities and mean energies are relatively large compared to the antineutrino properties, the mean Y_e might reach values >0.40 so that neutrino captures seriously compromise the success of the r-process. In this case, the r-abundances remain compatible with the solar distribution, but the total amount of ejected r-material is reduced to a few percent, because the production of iron-peak elements is favored. Proper neutrino physics, in particular also neutrino absorption, have to be included in BNSM simulations before final conclusions can be drawn concerning r-processing in this environment and concerning observational consequences like kilonovae, whose peak brightness and color temperature are sensitive to the composition-dependent opacity of the ejecta.

    2. Impact of weak interactions of free nucleons on the r-process in dynamical ejecta from neutron star mergers

      NASA Astrophysics Data System (ADS)

      Goriely, S.; Bauswein, A.; Just, O.; Pllumbi, E.; Janka, H.-Th.

      2015-10-01

      We investigate ?-interactions of free nucleons and their impact on the electron fraction (Ye) and r-process nucleosynthesis in ejecta characteristic of binary neutron star mergers (BNSMs). For that we employ trajectories from a relativistic BNSM model to represent the density-temperature evolutions in our parametric study. In the high-density environment, positron captures decrease the neutron richness at the high temperatures predicted by the hydrodynamic simulation. Circumventing the complexities of modelling three-dimensional neutrino transport, (anti)neutrino captures are parametrized in terms of prescribed neutrino luminosities and mean energies, guided by published results and assumed as constant in time. Depending sensitively on the adopted ?e-bar{? }_e luminosity ratio, neutrino processes increase Ye to values between 0.25 and 0.40, still allowing for a successful r-process compatible with the observed solar abundance distribution and a significant fraction of the ejecta consisting of r-process nuclei. If the ?e luminosities and mean energies are relatively large compared to the bar{? }_e properties, the mean Ye might reach values >0.40 so that neutrino captures seriously compromise the success of the r-process. In this case, the r-abundances remain compatible with the solar distribution, but the total amount of ejected r-material is reduced to a few per cent, because the production of iron-peak elements is favoured. Proper neutrino physics, in particular also neutrino absorption, have to be included in BNSM simulations before final conclusions can be drawn concerning r-processing in this environment and concerning observational consequences like kilonovae, whose peak brightness and colour temperature are sensitive to the composition-dependent opacity of the ejecta.

    3. Developments in precison mass measurements of short-lived r-process nuclei with CARIBU

      NASA Astrophysics Data System (ADS)

      Marley, S. T.; Aprahamian, A.; Mumpower, M.; Nystrom, A.; Paul, N.; Siegl, K.; Strauss, S.; Surman, R.; Clark, J. A.; Perez Galvan, A.; Savard, G.; Morgan, G.; Orford, R.

      2013-10-01

      The confluence of new radioactive beam facilities and modern precision mass spectrometry techniques now make it possible to measure masses of many neutron-rich nuclei important to nuclear structure and astrophysics. A recent mass sensitivity study (S. Brett et al., Eur. Phys. J., A 48, 184 (2012)) identified the nuclear masses that are the most influential to the final rapid-neutron capture process abundance distributions under various astrophysical scenarios. This work motivated a campaign of precision mass measurements using the Canadian Penning Trap (CPT) installed at the Californium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne National Laboratory. In order to measure the weakest and most short-lived (t1/2 < 150 ms) of these influential nuclei, a series of upgrades to the CARIBU and CPT systems have been developed. The implementation of these upgrades, the r-process mass measurements, and the status of CARIBU facilty will be discussed. This work performed under the auspices of NSERC, Canada, appl. # 216974, the U.S. DOE, Office of Nuclear Physics, under contracts DE-AC02-06CH11357, DE-FG02-91ER-40609, DE-FG02-98ER41086, & DE-AC52-07NA27344, and NSF Grants PHY08-22648 and PHY-106819.

    4. The origins of light and heavy r-process elements identified by chemical tagging of metal-poor stars

      E-print Network

      Tsujimoto, Takuji

      2014-01-01

      Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration gamma-ray burst. The hypothesis of a NS merger origin is reinforced by a theoretical update of nucleosynthesis in NS mergers successful in yielding r-process nuclides with A>130. On the other hand, whether the origin of light r-process elements are associated with nucleosynthesis in NS merger events remains unclear. We find a signature of nucleosynthesis in NS mergers from peculiar chemical abundances of stars belonging to the Galactic globular cluster M15. This finding combined with the recent nucleosynthesis results implies a potential diversity of nucleosynthesis in NS mergers. Based on these considerations, we are successful in the interpretation of an observed correlation between [light r-process/Eu] and [Eu/Fe] among Galactic halo stars and accordingly narrow down the role of supernova nucleosynthesis in the r-process pr...

    5. DETECTION OF ELEMENTS AT ALL THREE r-PROCESS PEAKS IN THE METAL-POOR STAR HD 160617

      SciTech Connect

      Roederer, Ian U.; Lawler, James E. E-mail: jelawler@wisc.edu

      2012-05-01

      We report the first detection of elements at all three r-process peaks in the metal-poor halo star HD 160617. These elements include arsenic and selenium, which have not been detected previously in halo stars, and the elements tellurium, osmium, iridium, and platinum, which have been detected previously. Absorption lines of these elements are found in archive observations made with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. We present up-to-date absolute atomic transition probabilities and complete line component patterns for these elements. Additional archival spectra of this star from several ground-based instruments allow us to derive abundances or upper limits of 45 elements in HD 160617, including 27 elements produced by neutron-capture reactions. The average abundances of the elements at the three r-process peaks are similar to the predicted solar system r-process residuals when scaled to the abundances in the rare earth element domain. This result for arsenic and selenium may be surprising in light of predictions that the production of the lightest r-process elements generally should be decoupled from the heavier r-process elements.

    6. The Hamburg/ESO R-process Enhanced Star survey (HERES) IV. Detailed abundance analysis and age dating of the strongly r-process enhanced stars CS 29491-069 and HE 1219-0312

      E-print Network

      Hayek, W; Christlieb, N; Eriksson, K; Korn, A J; Barklem, P S; Hill, V; Beers, T C; Farouqi, K; Pfeiffer, B; Kratz, K -L

      2009-01-01

      We report on a detailed abundance analysis of two strongly r-process enhanced, very metal-poor stars newly discovered in the HERES project, CS 29491-069 ([Fe/H]=-2.51, [r/Fe]=+1.1) and HE 1219-0312 ([Fe/H]=-2.96, [r/Fe]=+1.5). The analysis is based on high-quality VLT/UVES spectra and MARCS model atmospheres. We detect lines of 15 heavy elements in the spectrum of CS 29491-069, and 18 in HE 1219-0312; in both cases including the Th II 4019 {\\AA} line. The heavy-element abundance patterns of these two stars are mostly well-matched to scaled solar residual abundances not formed by the s-process. We also compare the observed pattern with recent high-entropy wind (HEW) calculations, which assume core-collapse supernovae of massive stars as the astrophysical environment for the r-process, and find good agreement for most lanthanides. The abundance ratios of the lighter elements strontium, yttrium, and zirconium, which are presumably not formed by the main r-process, are reproduced well by the model. Radioactive da...

    7. The Hamburg/ESO R-process enhanced star survey (HERES). IV. Detailed abundance analysis and age dating of the strongly r-process enhanced stars CS 29491-069 and HE 1219-0312

      NASA Astrophysics Data System (ADS)

      Hayek, W.; Wiesendahl, U.; Christlieb, N.; Eriksson, K.; Korn, A. J.; Barklem, P. S.; Hill, V.; Beers, T. C.; Farouqi, K.; Pfeiffer, B.; Kratz, K.-L.

      2009-09-01

      We report on a detailed abundance analysis of two strongly r-process enhanced, very metal-poor stars newly discovered in the HERES project, CS 29491-069 ([Fe/H]=-2.51, [r/Fe]=+1.1) and HE 1219-0312 ([Fe/H]=-2.96, [r/Fe]=+1.5). The analysis is based on high-quality VLT/UVES spectra and MARCS model atmospheres. We detect lines of 15 heavy elements in the spectrum of CS 29491-069, and 18 in HE 1219-0312; in both cases including the Th II 4019 Å line. The heavy-element abundance patterns of these two stars are mostly well-matched to scaled solar residual abundances not formed by the s-process. We also compare the observed pattern with recent high-entropy wind (HEW) calculations, which assume core-collapse supernovae of massive stars as the astrophysical environment for the r-process, and find good agreement for most lanthanides. The abundance ratios of the lighter elements strontium, yttrium, and zirconium, which are presumably not formed by the main r-process, are reproduced well by the model. Radioactive dating for CS 29491-069 with the observed thorium and rare-earth element abundance pairs results in an average age of 9.5 Gyr, when based on solar r-process residuals, and 17.6 Gyr, when using HEW model predictions. Chronometry seems to fail in the case of HE 1219-0312, resulting in a negative age due to its high thorium abundance. HE 1219-0312 could therefore exhibit an overabundance of the heaviest elements, which is sometimes called an “actinide boost”. Based on observations collected at the European Southern Observatory, Paranal, Chile (Proposal Number 170.D-0010). Table 8 is only available in electronic form at http://www.aanda.org

    8. New Rare Earth Element Abundance Distributions for the Sun and Five r-Process-Rich Very Metal-Poor Stars

      E-print Network

      Sneden, Christopher; Cowan, John J; Ivans, Inese I; Hartog, Elizabeth A Den

      2009-01-01

      We have derived new abundances of the rare-earth elements Pr, Dy, Tm, Yb, and Lu for the solar photosphere and for five very metal-poor, neutron-capture r-process-rich giant stars. The photospheric values for all five elements are in good agreement with meteoritic abundances. For the low metallicity sample, these abundances have been combined with new Ce abundances from a companion paper, and reconsideration of a few other elements in individual stars, to produce internally-consistent Ba, rare-earth, and Hf (56<= Z <= 72) element distributions. These have been used in a critical comparison between stellar and solar r-process abundance mixes.

    9. NEW RARE EARTH ELEMENT ABUNDANCE DISTRIBUTIONS FOR THE SUN AND FIVE r-PROCESS-RICH VERY METAL-POOR STARS

      SciTech Connect

      Sneden, Christopher; Lawler, James E.; Den Hartog, Elizabeth A.; Cowan, John J.; Ivans, Inese I. E-mail: jelawler@wisc.edu E-mail: cowan@nhn.ou.edu

      2009-05-15

      We have derived new abundances of the rare earth elements Pr, Dy, Tm, Yb, and Lu for the solar photosphere and for five very metal-poor, neutron-capture r-process-rich giant stars. The photospheric values for all five elements are in good agreement with meteoritic abundances. For the low-metallicity sample, these abundances have been combined with new Ce abundances from a companion paper, and reconsideration of a few other elements in individual stars, to produce internally consistent Ba, rare earth, and Hf (56 {<=} Z {<=} 72) element distributions. These have been used in a critical comparison between stellar and solar r-process abundance mixes.

    10. s- and r-process element abundances in the CMD of 47 Tucanae using the Robert Stobie Spectrograph on SALT

      E-print Network

      C. C. Worley; P. L. Cottrell; E. C. Wylie de Boer

      2008-02-04

      A recent study by Wylie et al 2006 has revealed that s-process element abundances are enhanced relative to iron in both red giant branch and asymptotic giant branch stars of 47 Tucanae. A more detailed investigation into s-process element abundances throughout the colour-magnitude diagram of 47 Tucanae is vital in order to determine whether the observed enhancements are intrinsic to the cluster. This paper explores this possibility through observational and theoretical means. The visibility of s- and r-process element lines in synthetic spectra of giant and dwarf stars throughout the colour magnitude diagram of 47 Tucanae has been explored. It was determined that a resolving power of 10 000 was sufficient to observe s-process element abundance variations in globular cluster giant branch stars. These synthetic results were compared with the spectra of eleven 47 Tucanae giant branch stars observed during the performance verification of the Robert Stobie Spectrograph on the Southern African Large Telescope. Three s-process elements, Zr, Ba, Nd, and one r-process element, Eu, were investigated. No abundance variations were found such that [X/Fe] = 0.0 +/- 0.5 dex. It was concluded that this resolving power, R ~ 5000, was not sufficient to obtain exact abundances but upper limits on the s-process element abundances could be determined.

    11. QUARK-NOVAE, COSMIC REIONIZATION, AND EARLY r-PROCESS ELEMENT PRODUCTION

      SciTech Connect

      Ouyed, Rachid; Pudritz, Ralph E.; Jaikumar, Prashanth

      2009-09-10

      We examine the case for quark-novae (QNe) as possible sources for the reionization and early metal enrichment of the universe. QNe are predicted to arise from the explosive collapse (and conversion) of sufficiently massive neutron stars into quark stars (QSs). A QN can occur over a range of timescales following the supernova (SN) event. For QNe that arise days to weeks after the SNe, we show that dual shock that arises as the QN ejecta encounter the SN ejecta can produce enough photons to reionize hydrogen in most of the intergalactic medium (IGM) by z {approx} 6. Such events can explain the large optical depth {tau} {sub e} {approx} 0.1 as measured by WMAP, if the clumping factor, C, of the material being ionized is smaller than 10. We suggest a way in which a normal initial mass function for the oldest stars can be reconciled with a large optical depth as well as the mean metallicity of the early IGM post reionization. We find that QN also make a contribution to r-process element abundances for atomic numbers A {>=} 130. We predict that the main cosmological signatures of QNe are the gamma-ray bursts that announce their birth. These will be clustered at redshifts in the range z {approx} 7-8 in our model.

    12. Quark-Novae, cosmic reionization, and early r-process element production

      E-print Network

      R. Ouyed; R. E. Pudritz; P. Jaikumar

      2009-06-30

      We examine the case for Quark-Novae (QNe) as possible sources for the reionization and early metal enrichment of the universe. Quark-Novae are predicted to arise from the explosive collapse (and conversion) of sufficiently massive neutron stars into quark stars. A Quark-Nova (QN) can occur over a range of time scales following the supernova event. For QNe that arise days to weeks after the supernovae, we show that dual-shock that arises as the QN ejecta encounter the supernova ejecta can produce enough photons to reionize hydrogen in most of the Inter-Galactic medium (IGM) by z ~ 6. Such events can explain the large optical depth tau_e ~ 0.1 as measured by WMAP, if the clumping factor, C, of the material being ionized is smaller than 10. We suggest a way in which a normal initial mass function (IMF) for the oldest stars can be reconciled with a large optical depth as well as the mean metallicity of the early IGM post reionization. We find that QN also make a contribution to r-process element abundances for atomic numbers A > 130. We predict that the main cosmological signatures of Quark-Novae are the gamma-ray bursts that announce their birth. These will be clustered at redshifts in the range z ~ 7-8 in our model.

    13. Export Control Requirements for Tritium Processing Design and R&D

      SciTech Connect

      Hollis, William Kirk; Maynard, Sarah-Jane Wadsworth

      2015-10-30

      This document will address requirements of export control associated with tritium plant design and processes. Los Alamos National Laboratory has been working in the area of tritium plant system design and research and development (R&D) since the early 1970’s at the Tritium Systems Test Assembly (TSTA). This work has continued to the current date with projects associated with the ITER project and other Office of Science Fusion Energy Science (OS-FES) funded programs. ITER is currently the highest funding area for the DOE OS-FES. Although export control issues have been integrated into these projects in the past a general guidance document has not been available for reference in this area. To address concerns with currently funded tritium plant programs and assist future projects for FES, this document will identify the key reference documents and specific sections within related to tritium research. Guidance as to the application of these sections will be discussed with specific detail to publications and work with foreign nationals.

    14. RNA polymerase I transcription and pre-rRNA processing are linked by specific SSU processome components

      PubMed Central

      Gallagher, Jennifer E.G.; Dunbar, David A.; Granneman, Sander; Mitchell, Brianna M.; Osheim, Yvonne; Beyer, Ann L.; Baserga, Susan J.

      2004-01-01

      Sequential events in macromolecular biosynthesis are often elegantly coordinated. The small ribosomal subunit (SSU) processome is a large ribonucleoprotein (RNP) required for processing of precursors to the small subunit RNA, the 18S, of the ribosome. We have found that a subcomplex of SSU processome proteins, the t-Utps, is also required for optimal rRNA transcription in vivo in the yeast Saccharomyces cerevisiae. The t-Utps are ribosomal chromatin (r-chromatin)-associated, and they exist in a complex in the absence of the U3 snoRNA. Transcription is required neither for the formation of the subcomplex nor for its r-chromatin association. The t-Utps are associated with the pre-18S rRNAs independent of the presence of the U3 snoRNA. This association may thus represent an early step in the formation of the SSU processome. Our results indicate that rRNA transcription and pre-rRNA processing are coordinated via specific components of the SSU processome. PMID:15489292

    15. Chemo-dynamical evolution model: Enrichment of r-process elements in the Local Group dwarf galaxies

      NASA Astrophysics Data System (ADS)

      Hirai, Yutaka; Ishimaru, Yuhri; Saitoh, Takayuki R.; Fujii, Michiko S.; Hidaka, Jun; Kajino, Toshitaka

      2015-08-01

      Enrichment of the r-process elements is expected to provide a critical clue to understand the formation history of galactic halos. Recent astronomical high dispersion observations of metal-poor stars have shown large dispersions in relative abundance ratios of r-process elements such as [Eu/Fe] in stars with [Fe/H] < -2.5. Astrophysical site(s) of r-process has, however, not been identified yet. Promising site(s) of r-process are core-collapse supernovae (CCSNe) and neutron-star mergers (NSMs). Recent nucleosynthesis studies have shown that r-process elements heavier than 110 of mass number are difficult to synthesize by CCSNe. On the other hand, several studies reported that NSMs can synthesize these elements due to their environment of low electron fraction. Previous chemical evolution model (e.g., Argast et al. 2004) of the Milky Way (MW) halo without dynamical evolution pointed out that the NSMs are difficult to reproduce observed dispersion in [Eu/Fe] vs. [Fe/H] due to their low rate 10-6 - 10-3 yr-1 for a MW size galaxy and the long delay time, t ? 100 Myr. In the present study, we carry out numerical simulations of galactic chemo-dynamical evolution using an N-body/smoothed particle hydrodynamics code, ASURA. We construct detailed chemo-dynamical evolution model for dwarf spheroidal galaxies (dSphs) assuming that the NSMs are the major source of the r-process elements. Our models successfully reproduce the observed dispersion in [Eu/Fe] vs. [Fe/H] if we set t < 500 Myr with the Galactic NSM rate ~10-4 yr-1. Moreover, our results are consistent with observed metallicity distribution and mass-metallicity relation of dSphs. We then find that the effects of gas mixing processes including metals in the star-forming region of a typical scale of giant molecular clouds ~ 10 - 100 pc play the significant roles in reproducing the measured dispersion in [Eu/Fe] vs. [Fe/H] of the metal-poor stars in dSphs. We also find that the star formation rate of ~ 10-3 M?yr-1 in early epoch (< 1 Gyr) of galactic halo evolution is necessary for this results. This study strongly supports that NSM is a major site of r-process.

    16. NMDA-R inhibition affects cellular process formation in Tilapia melanocytes; a model for pigmented adrenergic neurons in process formation and retraction.

      PubMed

      Ogundele, Olalekan Michael; Okunnuga, Adetokunbo Adedotun; Fabiyi, Temitope Deborah; Olajide, Olayemi Joseph; Akinrinade, Ibukun Dorcas; Adeniyi, Philip Adeyemi; Ojo, Abiodun Ayodele

      2014-06-01

      Parkinson's disease has long been described to be a product of dopamine and (or) melanin loss in the substanstia nigra (SN). Although most studies have focused on dopaminergic neurons, it is important to consider the role of pigment cells in the etiology of the disease and to create an in vitro live cell model for studies involving pigmented adrenergic cells of the SN in Parkinsonism. The Melanocytes share specific features with the pigmented adrenergic neurons as both cells are pigmented, contain adrenergic receptors and have cellular processes. Although the melanocyte cellular processes are relatively short and observable only when stimulated appropriately by epinephrine and other factors or molecules. This study employs the manipulation of N-Methyl-D-Aspartate Receptor (NMDA-R), a major receptor in neuronal development, in the process formation pattern of the melanocyte in order to create a suitable model to depict cellular process elongation and shortening in pigmented adrenergic cells. NMDA-R is an important glutamate receptor implicated in neurogenesis, neuronal migration, maturation and cell death, thus we investigated the role of NMDA-R potentiation by glutamate/KCN and its inhibition by ketamine in the behavior of fish scale melanocytes in vitro. This is aimed at establishing the regulatory role of NMDA-R in this cell type (melanocytes isolated form Tilapia) in a similar manner to what is observable in the mammalian neurons. In vitro live cell culture was prepared in modified Ringer's solution following which the cells were treated as follows; Control, Glutamate, Ketamine, Glutamate + Ketamine, KCN + Ketamine and KCN. The culture was maintained for 10 min and the changes were captured in 3D-Time frame at 0, 5 and 10 min for the control and 5, 7 and 10 min for each of the treatment category. Glutamate treatment caused formation of short cellular processes localized directly on the cell body while ketamine treatment (inhibition of NMDA-R) facilitated elongation of secondary cellular processes (highly branched) from primary major processes (Less branched); co-incubation of glutamate and ketamine induced short and highly branched process formation. Cyanide toxicity induced degeneration and reduction of cell size while co-treatment of cyanide and ketamine gave changes similar to that observed in glutamate-ketamine co-incubation. NMDA-R is present in the melanocytes. Activation of the receptor reduced elongation process, while inhibition of the receptor facilitated cell process elongation and branching. This confirms that like pigmented adrenergic cells of the nervous system, this cell contains NMDA-R and this receptor also regulates cell process elongation. The study also showed that inhibition of NMDA-R in melanocytes gave opposite outcomes to the role of the receptor in developing neurons; a function that is protective in adult neurons. PMID:24242214

    17. The Human Nucleolar Protein FTSJ3 Associates with NIP7 and Functions in Pre-rRNA Processing

      PubMed Central

      Morello, Luis G.; Coltri, Patricia P.; Quaresma, Alexandre J. C.; Simabuco, Fernando M.; Silva, Tereza C. L.; Singh, Guramrit; Nickerson, Jeffrey A.; Oliveira, Carla C.; Moore, Melissa J.; Zanchin, Nilson I. T.

      2011-01-01

      NIP7 is one of the many trans-acting factors required for eukaryotic ribosome biogenesis, which interacts with nascent pre-ribosomal particles and dissociates as they complete maturation and are exported to the cytoplasm. By using conditional knockdown, we have shown previously that yeast Nip7p is required primarily for 60S subunit synthesis while human NIP7 is involved in the biogenesis of 40S subunit. This raised the possibility that human NIP7 interacts with a different set of proteins as compared to the yeast protein. By using the yeast two-hybrid system we identified FTSJ3, a putative ortholog of yeast Spb1p, as a human NIP7-interacting protein. A functional association between NIP7 and FTSJ3 is further supported by colocalization and coimmunoprecipitation analyses. Conditional knockdown revealed that depletion of FTSJ3 affects cell proliferation and causes pre-rRNA processing defects. The major pre-rRNA processing defect involves accumulation of the 34S pre-rRNA encompassing from site A? to site 2b. Accumulation of this pre-rRNA indicates that processing of sites A0, 1 and 2 are slower in cells depleted of FTSJ3 and implicates FTSJ3 in the pathway leading to 18S rRNA maturation as observed previously for NIP7. The results presented in this work indicate a close functional interaction between NIP7 and FTSJ3 during pre-rRNA processing and show that FTSJ3 participates in ribosome synthesis in human cells. PMID:22195017

    18. Current status and prospects of radiation processing studies in Taiwan, R. O. C.

      NASA Astrophysics Data System (ADS)

      Fu, Ying-Kai

      The research on radiation processing in past 5 years in Taiwan covers industrial application of radiation-induced polymerization and curing, medical application of radiosterilization of medical supplies, chemicals, and amniotic membrane for wound dressing as well as agricultural application of food irradiation and genogenesis etc. Radiation-induced polymerization applied on wood and bamboo plastic composite of methyl methacrylate, radiation curing on polyurethane and silicon rubber for biomedical material using to separate oxygen from nitrogen and on crosslinking of pp and ps for artificial skin for wound dressing were all success. Radio-sterilization of disposable medical supplies appears for immediate application after the studies of the dose requirement of several radioresistant microorganisms, dose distribution measured by chemical dosimeters of ceric sulfate and Fricke dosimeter as well as quality control system were completed. The radiosterilization study of tetracycline - HCl and few detoxic agents like atropine sulfate and toxogonin has shown the promising results on radiosterilization of chemicals, the radiosterilization of amniotic membrane for wound dressing are also success. Food irradiation on sprouting inhibition of potatoes, garlic etc, on radiodisinfestation of cereal insects, tobacco bettles, soybean insects, and flour beetles, as well as on frog legs and porks have been also discussed. The legislation on radiosterilization of medical supplies and food irradiation of 14 items has been approved by National Health Administration, R.O.C. in July of 1982 and January of 1985 respectively. Even 24 hrs-operation of 1 Mega curie irradiation plant at INER can not satisfy the requirement of radiosterilization of medical supplies. A private commercial irradiation plant is urgently needed in Taiwan other than at INER now.

    19. The Role of Fission in Neutron Star Mergers and Its Impact on the r-Process Peaks

      NASA Astrophysics Data System (ADS)

      Eichler, M.; Arcones, A.; Kelic, A.; Korobkin, O.; Langanke, K.; Marketin, T.; Martinez-Pinedo, G.; Panov, I.; Rauscher, T.; Rosswog, S.; Winteler, C.; Zinner, N. T.; Thielemann, F.-K.

      2015-07-01

      Comparing observational abundance features with nucleosynthesis predictions of stellar evolution or explosion simulations, we can scrutinize two aspects: (a) the conditions in the astrophysical production site and (b) the quality of the nuclear physics input utilized. We test the abundance features of r-process nucleosynthesis calculations for the dynamical ejecta of neutron star merger simulations based on three different nuclear mass models: The Finite Range Droplet Model, the (quenched version of the) Extended Thomas Fermi Model with Strutinsky Integral, and the Hartree-Fock-Bogoliubov mass model. We make use of corresponding fission barrier heights and compare the impact of four different fission fragment distribution models on the final r-process abundance distribution. In particular, we explore the abundance distribution in the second r-process peak and the rare-earth sub-peak as a function of mass models and fission fragment distributions, as well as the origin of a shift in the third r-process peak position. The latter has been noticed in a number of merger nucleosynthesis predictions. We show that the shift occurs during the r-process freeze-out when neutron captures and ?-decays compete and an (n,?)-(?,n) equilibrium is no longer maintained. During this phase neutrons originate mainly from fission of material above A = 240. We also investigate the role of ?-decay half-lives from recent theoretical advances, which lead either to a smaller amount of fissioning nuclei during freeze-out or a faster (and thus earlier) release of fission neutrons, which can (partially) prevent this shift and has an impact on the second and rare-earth peak as well.

    20. Spectroscopic Studies of Extremly Metal-Poor Stars with Subaru/HDS:II.The r-process Elements, Including Thorium

      E-print Network

      S. Honda; W. Aoki; T. Kajino; H. Ando; T. C. Beers; H. Izumiura; K. Sadakane; M. Takada-Hidai

      2004-02-12

      We present the abundance analyses for the neutron-capture elements, and discuss the observed abundance distributions in very metal-poor stars with excesses of r-process elements. As has been found by previous abundance studies, the star-to-star scatter in the abundances of neutron-capture elements are very large. The abundance patterns of the heavy neutron-capture elements (56 $\\leq$ Z $\\leq$ 70) in seven objects with moderate to large excesses of the neutron-capture elements are similar to that of the solar system r-process component. These results strongly suggest that the heavy neutron-capture elements in these objects are primarily synthesized by the r-process. On the other hand, the abundance ratios of the light neutron-capture elements (38 $\\leq$ Z $\\leq$ 46) exhibit a rather large dispersion. Our inspection of the correlation between Sr and Ba abundances in very metal-poor stars reveals that the dispersion of the Sr abundances clearly decreases with increasing Ba abundance. This results support previous suggestions that the light neutron-capture elements are likely to have been produced in different astrophysical sites from those associated with the production of the heavier ones. The Th/Eu abundance ratios (log(Th/Eu)) measured for the seven r-process-enhanced stars range from -0.10 to -0.59. Since these very metal-poor stars are believed to be formed in the early Galaxy, this result means that a small dispersion appears in the abundance ratios between Th and rare-earth elements, such as Eu, in very metal-poor stars. In order to apply the Th/Eu ratios to estimates of stellar ages, further understanding for the Th production by the r-process nucleosynthesis is required.

    1. Consultative Processes in a Small Democracy: D.A.R.E. New Zealand.

      ERIC Educational Resources Information Center

      Sanders, Owen

      This paper outlines the approach to drug abuse education being taken by D.A.R.E. (Drug Abuse Resistance Education) New Zealand, a distinctly indigenous response characterized by a consultative association involving the police, the schools, and the community. A key feature of D.A.R.E. New Zealand is the extent to which parents and the wider…

    2. Tool Supported Detection and Judgment of Nonconformance in Process Execution Nico Zazworka, Victor R. Basili

      E-print Network

      Basili, Victor R.

      development life cycles, models, and processes. The goal of a major set of these processes is to assure to the project manager. Keywords: Process Conformance, Process Verification, Risk Assessment, Process Measurement, and practices involved in the production and evolution of a software product throughout the software life cycle

    3. ? -decay half-lives of neutron-rich nuclei at A ~ 110 on r-process path

      NASA Astrophysics Data System (ADS)

      Nishizuka, Ippei; Sumikama, Toshiyuki; Browne, Frank; Bruce, Alison; Nishimura, Shunji; Doornenbal, Pieter; Lorusso, Giuseppe; Patel, Zena; Rice, Simon; Sinclair, Laura; Soderstom, Par-Ander; Watanabe, Hiroshi; Wu, Jin; Xu, Zhengyu; Yagi, Ayumi; Eurica Collaboration

      2014-09-01

      About half of the elements heavier than iron are thought to be produced by rapid-neutron capture process (r-process). The observed natural abundance in solar system was underestimated by a theoretical model at A ~ 110 , which uses ?-decay half-lives. In the present study, we measured new ? half-lives of neutron-rich nuclei on r-process path at RIBF in RIKEN. The nuclei of interest were produced by in-flight fission of uranium beam in beryllium target. The WAS3ABi detector which was 5 stacked double-sided silicon strip detectors (60 × 40 × 1 mm3), was used for the implantation of ions and the detection of both the implanted ions and the subsequently-emitted ? rays. It is essential to make a position correlation between the mother nucleus and the ? rays. In this talk, the analysis of the position correlation will be presented in detail. Preliminary results will be also shown.

    4. A real-time GNSS-R system based on software-defined radio and graphics processing units

      NASA Astrophysics Data System (ADS)

      Hobiger, Thomas; Amagai, Jun; Aida, Masanori; Narita, Hideki

      2012-04-01

      Reflected signals of the Global Navigation Satellite System (GNSS) from the sea or land surface can be utilized to deduce and monitor physical and geophysical parameters of the reflecting area. Unlike most other remote sensing techniques, GNSS-Reflectometry (GNSS-R) operates as a passive radar that takes advantage from the increasing number of navigation satellites that broadcast their L-band signals. Thereby, most of the GNSS-R receiver architectures are based on dedicated hardware solutions. Software-defined radio (SDR) technology has advanced in the recent years and enabled signal processing in real-time, which makes it an ideal candidate for the realization of a flexible GNSS-R system. Additionally, modern commodity graphic cards, which offer massive parallel computing performances, allow to handle the whole signal processing chain without interfering with the PC's CPU. Thus, this paper describes a GNSS-R system which has been developed on the principles of software-defined radio supported by General Purpose Graphics Processing Units (GPGPUs), and presents results from initial field tests which confirm the anticipated capability of the system.

    5. Analysis of 26 Barium Stars II. Contributions of s-, r- and p-processes in the production of heavy elements

      E-print Network

      Dinah M. Allen; Beatriz Barbuy

      2006-04-04

      Barium stars show enhanced abundances of the slow neutron capture (s-process) heavy elements, and for this reason they are suitable objects for the study of s-process elements. The aim of this work is to quantify the contributions of the s-, r- and p-processes for the total abundance of heavy elements from abundances derived for a sample of 26 barium stars. The abundance ratios between these processes and neutron exposures were studied. The abundances of the sample stars were compared to those of normal stars thus identifying the fraction relative to the s-process main component. The fittings of the sigmaN curves (neutron capture cross section times abundance, plotted against atomic mass number) for the sample stars suggest that the material from the companion asymptotic giant branch star had approximately the solar isotopic composition as concerns fractions of abundances relative to the s-process main component. The abundance ratios of heavy elements, hs, ls and s and the computed neutron exposure are similar to those of post-AGB stars. For some sample stars, an exponential neutron exposure fits well the observed data, whereas for others, a single neutron exposure provides a better fit. The comparison between barium and AGB stars supports the hypothesis of binarity for the barium star formation. Abundances of r-elements that are part of the s-process path in barium stars are usually higher than those in normal stars,and for this reason, barium stars seemed to be also enriched in r-elements, although in a lower degree than s-elements. No dependence on luminosity classes was found in the abundance ratios behaviour among the dwarfs and giants of the sample barium stars.

    6. Thorium-rich halo star HD221170: further evidence against the universality of the r-process

      E-print Network

      Alexander Yushchenko; Vera Gopka; Stephane Goriely; Faig Musaev; Angelina Shavrina; Chulhee Kim; Young Woon Kang; Juliana Kuznietsova; Vladimir Yushchenko

      2004-09-22

      We report the abundance determination in the atmosphere of the bright halo star HD221170. The spectra were taken with the Terskol Observatory's 2.0-m telescope with a resolution R=45000 and signal-to-noise ratio up to 250 in the wavelength region 3638-10275 \\AA. The adopted atmospheric parameters correspond to an effective temperature \\Tef=4475 K, a surface gravity \\lgg=1.0, a microturbulent velocity \\vmi=1.7 \\kms, and a macroturbulent velocity \\vma=4 \\kms. The abundances of 43 chemical elements were determined with the method of spectrum synthesis. The large overabundances (by 1 dex relative to iron) of elements with Z$>38$ are shown to follow the same pattern as the solar r-abundances. The present HD221170 analysis confirms the non-universality of the r-process, or more exactly the observation that the astrophysical sites hosting the r-process do not always lead to a unique relative abundance distribution for the bulk Ba to Hg elements, the Pb-peak elements, and the actinides.

    7. Inhibitory repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex modulates early affective processing.

      PubMed

      Zwanzger, Peter; Steinberg, Christian; Rehbein, Maimu Alissa; Bröckelmann, Ann-Kathrin; Dobel, Christian; Zavorotnyy, Maxim; Domschke, Katharina; Junghöfer, Markus

      2014-11-01

      The dorsolateral prefrontal cortex (dlPFC) has often been suggested as a key modulator of emotional stimulus appraisal and regulation. Therefore, in clinical trials, it is one of the most frequently targeted regions for non-invasive brain stimulation such as repetitive transcranial magnetic stimulation (rTMS). In spite of various encouraging reports that demonstrate beneficial effects of rTMS in anxiety disorders, psychophysiological studies exploring the underlying neural mechanisms are sparse. Here we investigated how inhibitory rTMS influences early affective processing when applied over the right dlPFC. Before and after rTMS or sham stimulation, subjects viewed faces with fearful or neutral expressions while whole-head magnetoencephalography (MEG) was recorded. Due to the disrupted functioning of the right dlPFC, visual processing in bilateral parietal, temporal, and occipital areas was amplified starting at around 90 ms after stimulus onset. Moreover, increased fear-specific activation was found in the right TPJ area in a time-interval between 110 and 170 ms. These neurophysiological effects were reflected in slowed reaction times for fearful, but not for neutral faces in a facial expression identification task while there was no such effect on a gender discrimination control task. Our study confirms the specific and important role of the dlPFC in regulation of early emotional attention and encourages future clinical research to use minimal invasive methods such as transcranial magnetic (TMS) or direct current stimulation (tDCS). PMID:25019678

    8. Search for spin-orbit-force reduction at {sup 106,108}Zr around r-process path

      SciTech Connect

      Sumikama, T.; Yoshinaga, K.; Watanabe, H.; and others

      2012-11-12

      Shell gap at the magic number N= 82 is important to reproduce the 2nd peak of r-process abundance. If a spin-orbit force is reduced in a very neutron-rich region, a shell quenching at N= 82 and a new shell closure at N70 are predicted. A shell evolution by the spin-orbit-force reduction can be searched for through the shape evolution of Zr isotopes around an expected double magic nuclei, {sup 110}Zr(Z = 40,N = 70). We performed {beta}-{gamma} and isomer spectroscopy at RIBF to observe low-lying states in {sup 106,108}Zr. The present results indicate a well deformed shape for {sup 106,108}Zr. The drastic reduction of the spin-orbit force most likely does not occur around {sup 110}Zr on an r-process path.

    9. Rolling Deck to Repository (R2R): Programmatic Quality Assessment and Processing of Marine Gravity and Magnetic Data and Associated Metadata

      NASA Astrophysics Data System (ADS)

      Morton, J. J.; Ferrini, V.; O'hara, S. H.; Arko, R. A.; Carbotte, S. M.; Coakley, B.

      2011-12-01

      With its global capability and diverse array of sensors, the U.S. academic research fleet is an integral component of ocean exploration. The Rolling Deck to Repository (R2R) Program provides a central shore-side gateway for underway data from the U.S. academic research fleet, with the primary goal of preserving and documenting routine underway data. Programmatic tools for Quality Assessment (QA) of multiple underway data types are being developed to provide prompt feedback to shipboard operators and inform down-stream science users. QA tools are being developed in object oriented PHP with modular components that can be distributed for use by the community. Programmatic data processing (DP) tools for select data types are also being developed. We report on recent progress with QA and DP tools developed for underway gravity and magnetics data. For magnetics data, DP includes despiking and removal of bad data, merging with navigation, turn removal, calculation of a layback position, and removal of the IGRF to produce a magnetic anomaly. For gravity data, DP involves merging with navigation, corrections for speed and heading (Eötvös) and latitude, some basic filtering, removing bad data, subsampling, and drift corrections. All of these tools follow a programmatic workflow that requires minimal human intervention. Advanced processing which requires human intervention is left to the science user. These tools make use of metadata specific to each device and data type, as well as customizable thresholds and processing parameters. The full suite of metadata that describes each data set, the quality assessment parameters and results, as well as processing steps will accompany the data being submitted to the National Geophysical Data Center. In addition to QA reports for raw data files, day plots are also produced at each step to allow for quick observation and verification of the data quality and processing steps. These plots will also be delivered with the data files. The result of data processing for gravity and magnetics data is a quality assessed multiplexed file (MGD77T). In addition, web tools are being developed to provide science users and operators with a quick and intuitive interface for reviewing QA results.

    10. When Process Mining Meets Bioinformatics R.P. Jagadeesh Chandra Bose1,2

      E-print Network

      van der Aalst, Wil

      . Process mining techniques are able to extract knowledge from such traces and provide a welcome extension construct process models (e.g., Petri nets or BPMN models) from event logs [2]. Discovery is not restricted

    11. A two-step enzymatic resolution process for large-scale production of (S)- and (R)-ethyl-3-hydroxybutyrate.

      PubMed

      Fishman, A; Eroshov, M; Dee-Noor, S S; van Mil, J; Cogan, U; Effenberger, R

      2001-08-01

      An efficient two-step enzymatic process for production of (R)- and (S)-ethyl-3-hydroxybutyrate (HEB), two important chiral intermediates for the pharmaceutical market, was developed and scaled-up to a multikilogram scale. Both enantiomers were obtained at 99% chemical purity and over 96% enantiomeric excess, with a total process yield of 73%. The first reaction involved a solvent-free acetylation of racemic HEB with vinylacetate for the production of (S)-HEB. In the second reaction, (R)-enriched ethyl-3-acetoxybutyrate (AEB) was subjected to alcoholysis with ethanol to derive optically pure (R)-HEB. Immobilized Candida antarctica lipase B (CALB) was employed in both stages, with high productivity and selectivity. The type of butyric acid ester influenced the enantioselectivity of the enzyme. Thus, extending the ester alkyl chain from ethyl to octyl resulted in a decrease in enantiomeric excess, whereas using bulky groups such as benzyl or t-butyl, improved the enantioselectivity of the enzyme. A stirred reactor was found unsuitable for large-scale production due to attrition of the enzyme particles and, therefore, a batchwise loop reactor system was used for bench-scale production. The immobilized enzyme was confined to a column and the reactants were circulated through the enzyme bed until the targeted conversion was reached. The desired products were separated from the reaction mixture in each of the two stages by fractional distillation. The main features of the process are the exclusion of solvent (thus ensuring high process throughput), and the use of the same enzyme for both the acetylation and the alcoholysis steps. Kilogram quantities of (S)-HEB and (R)-HEB were effectively prepared using this unit, which can be easily scaled-up to produce industrial quantities. PMID:11400099

    12. Uranium lines in the spectra of peculiar A stars - A search for recent r-process events

      NASA Technical Reports Server (NTRS)

      Cowley, C. R.; Adelman, S. J.

      1975-01-01

      Uranium wavelengths in the spectra of Ap stars are studied to see if they give any indication of a recent r-process event. It is concluded that there is no credible evidence for an admixture of uranium-235 in these stars, which would imply such an event. The evidence, though negative, is badly confused by blending of lines, and a final judgement must wait for an observational clarification of the situation.

    13. Rea1, a Dynein-related Nuclear AAA-ATPase, Is Involved in Late rRNA Processing and Nuclear Export of 60 S Subunits*S

      E-print Network

      Nissan, Tracy

      Rea1, a Dynein-related Nuclear AAA-ATPase, Is Involved in Late rRNA Processing and Nuclear Export in the significant reduction of mature 60 S subunits con- comitant with defects in pre-rRNA processing and late pre-60 S ribosome stability following ITS2 cleavage and prior to the generation of mature 5.8 S rRNA

    14. Neutrino fluence after r-process freeze-out and abundances of Te isotopes in presolar diamonds

      E-print Network

      Y. -Z. Qian; P. Vogel; G. J. Wasserburg

      1998-08-25

      Using the data of Richter et al. (1998) on Te isotopes in diamond grains from a meteorite, we derive bounds on the neutrino fluence and the decay timescale of the neutrino flux relevant for the supernova r-process. Our new bound on the neutrino fluence F after freeze-out of the r-process peak at mass number A = 130 is more stringent than the previous bound F 0.65 s. In particular, it requires that a fluence of F = 0.031 be provided by a neutrino flux with tau diamonds are retained while the radioactive ones are lost from the diamonds upon decay after implantation (Ott 1996). We consider that the nanodiamonds are condensed in an environment with C/O > 1 in the expanding supernova debris or from the exterior H envelope. The implantation of nuclei would have occurred 10**4-10**6 s after r-process freeze-out. This time interval may be marginally sufficient to permit adequate cooling upon expansion for the formation of diamond grains. The mechanisms of preferential retention/loss of the implanted nuclei are not well understood.

    15. NEW ABUNDANCE DETERMINATIONS OF CADMIUM, LUTETIUM, AND OSMIUM IN THE r-PROCESS ENRICHED STAR BD +17 3248 {sup ,}

      SciTech Connect

      Roederer, Ian U.; Sneden, Christopher; Lawler, James E.; Cowan, John J.

      2010-05-01

      We report the detection of Cd I (Z = 48), Lu II (Z = 71), and Os II (Z = 76) in the metal-poor star BD +17 3248. These abundances are derived from an ultraviolet spectrum obtained with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. This is the first detection of these neutron-capture species in a metal-poor star enriched by the r process. We supplement these measurements with new abundances of Mo I, Ru I, and Rh I derived from an optical spectrum obtained with the High Resolution Echelle Spectrograph on Keck. Combined with previous abundance derivations, 32 neutron-capture elements have been detected in BD +17 3248, the most complete neutron-capture abundance pattern in any metal-poor star to date. The light neutron-capture elements (38 {<=} Z {<=} 48) show a more pronounced even-odd effect than expected from current solar system r-process abundance predictions. The age for BD +17 3248 derived from the Th II/Os II chronometer is in better agreement with the age derived from other chronometers than the age derived from Th II/Os I. New Hf II abundance derivations from transitions in the ultraviolet are lower than those derived from transitions in the optical, and the lower Hf abundance is in better agreement with the scaled solar system r-process distribution.

    16. R&D for the Post-EP Processes of Superconducting RF Cavity

      SciTech Connect

      Saeki, Takayuki; Funahashi, Y.; Hayano, H.; Kato, Seigo; Nishiwaki, Michiru; Sawabe, Motoaki; Ueno, Kenji; Watanabe, K.; Antoine, Claire; Berry, Stefurn; Eozenou, F.; Gasser, Y.; Visentin, B.; Clemens, William A.; Geng, Rongli; Manus, Robert; Tyagi, Puneet

      2009-11-01

      The Electro-Polishing (EP) process is the best candidate of final surface treatment for the production of ILC cavities. Nevertheless, the broad distribution of the gradient caused by field emitters in cavities is sitll a serious problem for the EP process. A candidate source of field emitter is the sulfur component which is produced in the EP process and remains the inner-surface of cavities. We studied the effect of Ethanole- and degreaser-rinse processes after the EP process by a unique method. Moreover, we tried to test the sponge cleaning as the post-EP process to remove the field emitter inside the cavcity. This article describe the results of series tests of the post-EP process at KEK.

    17. PAL[R] Services Being Measured through Scientifically-Based Evaluation Process

      ERIC Educational Resources Information Center

      Perspectives in Peer Programs, 2007

      2007-01-01

      In January 2006, PAL[R] Peer Assistance and Leadership, a Promising Prevention Program of Workers Assistance Program, Inc. (WAP), received a $30,000 grant from the Center for Substance Abuse Prevention (CSAP) in order to be scientifically-evaluated on the outcomes and effectiveness of its programs and services. According to the grant, the…

    18. Nine new metal-poor stars on the subgiant and red horizontal branches with high levels of r-process enhancement

      NASA Astrophysics Data System (ADS)

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

      2014-12-01

      We report the discovery of nine metal-poor stars with high levels of r-process enhancement (+0.81 ? [Eu/Fe] ? +1.13), including six subgiants and three stars on the red horizontal branch. We also analyse four previously known r-process-enhanced metal-poor red giants. From this sample of 13 stars, we draw the following conclusions. (1) High levels of r-process enhancement are found in a broad range of stellar evolutionary states, reaffirming that this phenomenon is not associated with a chemical peculiarity of red giant atmospheres. (2) Only 1 of 10 stars observed at multiple epochs shows radial-velocity variations, reaffirming that stars with high levels of r-process enhancement are not preferentially found among binaries. (3) Only 2 of the 13 stars are highly enhanced in C and N, indicating that there is no connection between high levels of r-process enhancement and high levels of C and N. (4) The dispersions in [Sr/Ba] and [Sr/Eu] are larger than the dispersions in [Ba/Eu] and [Yb/Eu], suggesting that the elements below the second r-process peak do not always scale with those in the rare Earth domain, even within the class of highly-r-process-enhanced stars. (5) The light-element (12 ? Z ? 30) abundances of highly-r-process-enhanced stars are indistinguishable from those with normal levels of r-process material at the limit of our data, 3.5 per cent (0.015 dex) on average. The nucleosynthetic sites responsible for the large r-process enhancements did not produce any detectable light-element abundance signatures distinct from normal core-collapse supernovae.

    19. Discovery of a strongly r-process enhanced extremely metal-poor star LAMOST J110901.22+075441.8

      NASA Astrophysics Data System (ADS)

      Li, Hai-Ning; Aoki, Wako; Honda, Satoshi; Zhao, Gang; Christlieb, Norbert; Suda, Takuma

      2015-08-01

      We report the discovery of an extremely metal-poor (EMP) giant, LAMOST J110901.22+075441.8, which exhibits a large excess of r-process elements with [Eu/Fe] ? +1.16. The star is one of the newly discovered EMP stars identified from the LAMOST low-resolution spectroscopic survey and a high-resolution follow-up observation with the Subaru Telescope. Stellar parameters and elemental abundances have been determined from the Subaru spectrum. Accurate abundances for a total of 23 elements including 11 neutron-capture elements from Sr through Dy have been derived for LAMOST J110901.22+075441.8. The abundance pattern of LAMOST J110901.22+075441.8 in the range of C through Zn is in line with the “normal” population of EMP halo stars, except that it shows a notable underabundance in carbon. The heavy element abundance pattern of LAMOST J110901.22+075441.8 is in agreement with other well studied cool r?II metal-poor giants such as CS 22892–052 and CS 31082–001. The abundances of elements in the range from Ba through Dy match the scaled solar r-process pattern well. LAMOST J110901.22+075441.8 provides the first detailed measurements of neutron-capture elements among r–II stars at such low metallicity with [Fe/H] ? ?3.4, and exhibits similar behavior as other r–II stars in the abundance ratio of Zr/Eu as well as Sr/Eu and Ba/Eu.

    20. Low-mass supernovae in the early Galactic halo: source of the double r/s-process enriched halo stars?

      E-print Network

      Albert A. Zijlstra

      2003-12-18

      Several stars at the low-metallicity extreme of the Galactic halo ([Fe/H]=-2.5) show strong enhancements of both s-process and r-process elements. The presence of s-process elements in main-sequence stars is explained via mass transfer from an AGB companion star in a binary system. r-Process elements originate in type-II supernovae and also require mass transfer. It is however unclear how pollution by both an AGB star and a supernova could have occured. Here I show that the initial--final-mass relation steepens at low metallicity, due to low mass-loss efficiency. This may cause the degenerate cores of low-Z, high-mass AGB stars to reach the Chandresekhar mass, leading to an Iben & Renzini-type-1.5 supernova. Such supernovae can explain both the enhancement patterns and the metallicity dependence of the double-enhanced halo stars. Reduced mass loss efficiency predicts more massive remnants in metal-poor globular clusters. The evidence for a high M/L population in the cores of globular clusters is briefly discussed.

    1. PRETREATMENT AND FRACTIONATION OF CORN STOVER BY AMMONIA RECYCLE PERCOLATION PROCESS. (R831645)

      EPA Science Inventory

      Corn stover was pretreated with aqueous ammonia in a flow-through column reactor,
      a process termed as Ammonia Recycle Percolation (ARP). The aqueous ammonia causes
      swelling and efficient delignification of biomass at high temperatures. The ARP
      process solubilizes abou...

    2. 3D VISUALIZATION OF CONSTRUCTION PROCESSES AND Vineet R. Kamat1

      E-print Network

      Kamat, Vineet R.

      . In the construction industry, complex decisions yielding maximum benefit are an essential component of process design of construction process modelling (e.g. STROBOSCOPE), the Visualization/Animation aspect has mainly focused visualization/animation tools currently available commercially are restricted to two dimensions (e.g., Proof

    3. Chemistry of the Sagittarius dwarf galaxy: A top-light initial mass function, outflows, and the R-process

      SciTech Connect

      McWilliam, Andrew; Wallerstein, George; Mottini, Marta E-mail: walleg@u.washington.edu

      2013-12-01

      From chemical abundance analysis of stars in the Sagittarius dwarf spheroidal galaxy (Sgr), we conclude that the ?-element deficiencies cannot be due to the Type Ia supernova (SN Ia) time-delay scenario of Tinsley. Instead, the evidence points to low [?/Fe] ratios resulting from an initial mass function (IMF) deficient in the highest mass stars. The critical evidence is the 0.4 dex deficiency of [O/Fe], [Mg/Fe], and other hydrostatic elements, contrasting with the normal trend of r-process [Eu/Fe] {sub r} with [Fe/H]. Supporting evidence comes from the hydrostatic element (O, Mg, Na, Al, Cu) [X/Fe] ratios, which are inconsistent with iron added to the Milky Way (MW) disk trends. Also, the ratio of hydrostatic to explosive (Si, Ca, Ti) element abundances suggests a relatively top-light IMF. Abundance similarities with the LMC, Fornax, and IC 1613 suggest that their ?-element deficiencies also resulted from IMFs lacking the most massive SNe II. The top-light IMF, as well as the normal trend of r-process [Eu/Fe] {sub r} with [Fe/H] in Sgr, indicates that massive SNe II (?30 M {sub ?}) are not major sources of r-process elements. High [La/Y] ratios, consistent with leaky-box chemical evolution, are confirmed but ?0.3 dex larger than theoretical asymptotic giant branch (AGB) predictions. This suggests that a substantial increase in the theoretical {sup 13}C pocket in low-mass AGB stars is required. Sgr has the lowest [Rb/Zr] ratios known, consistent with pollution by low-mass (?2 M {sub ?}) AGB stars near [Fe/H] = –0.6, likely resulting from leaky-box chemical evolution. The [Cu/O] trends in Sgr and the MW suggest that Cu yields increase with both metallicity and stellar mass, as expected from Cu production by the weak s-process in massive stars. Finally, we present an updated hyperfine splitting line list, an abundance analysis of Arcturus, and further develop our error analysis formalism.

    4. FLEXIBLE APPLICATION OF THE JLAB PANSOPHY INFORMATION SYSTEM FOR PROJECT REPORTS, PROCESS MONITORING, AND R&D SAMPLE TRACKING

      SciTech Connect

      Valerie Bookwalter; Bonnie Madre; Charles Reece

      2008-02-12

      The use and features of the JLab SRF Institute IT system Pansophy1,2 continue to expand. In support of the cryomodule rework project for CEBAF a full set of web-based travelers has been implemented and an integrated set of live summary reports has been created. A graphical user interface within the reports enables navigation to either higher-level summaries or drill-down to the original source data. In addition to collection of episodic data, Pansophy is now used to capture, coordinate, and display continuously logged process parameter that relate to technical water systems and clean room environmental conditions. In a new expansion, Pansophy is being used to collect and track process and analytical data sets associated with SRF material samples that are part of the surface creation, processing, and characterization R&D program.

    5. Molecular diversity of eukaryotes in municipal wastewater treatment processes as revealed by 18S rRNA gene analysis.

      PubMed

      Matsunaga, Kengo; Kubota, Kengo; Harada, Hideki

      2014-01-01

      Eukaryotic communities involved in sewage treatment processes have been investigated by morphological identification, but have not yet been well-characterized using molecular approaches. In the present study, eukaryotic communities were characterized by constructing 18S rRNA gene clone libraries. The phylogenetic affiliations of a total of 843 clones were Alveolata, Fungi, Rhizaria, Euglenozoa, Stramenopiles, Amoebozoa, and Viridiplantae as protozoans and Rotifera, Gastrotricha, and Nematoda as metazoans. Sixty percent of the clones had <97% sequence identity to described eukaryotes, indicating the greater diversity of eukaryotes than previously recognized. A core OTU closely related to Epistylis chrysemydis was identified, and several OTUs were shared by 4-8 libraries. Members of the uncultured lineage LKM11 in Cryptomycota were predominant fungi in sewage treatment processes. This comparative study represents an initial step in furthering understanding of the diversity and role of eukaryotes in sewage treatment processes. PMID:25491751

    6. Molecular Diversity of Eukaryotes in Municipal Wastewater Treatment Processes as Revealed by 18S rRNA Gene Analysis

      PubMed Central

      Matsunaga, Kengo; Kubota, Kengo; Harada, Hideki

      2014-01-01

      Eukaryotic communities involved in sewage treatment processes have been investigated by morphological identification, but have not yet been well-characterized using molecular approaches. In the present study, eukaryotic communities were characterized by constructing 18S rRNA gene clone libraries. The phylogenetic affiliations of a total of 843 clones were Alveolata, Fungi, Rhizaria, Euglenozoa, Stramenopiles, Amoebozoa, and Viridiplantae as protozoans and Rotifera, Gastrotricha, and Nematoda as metazoans. Sixty percent of the clones had <97% sequence identity to described eukaryotes, indicating the greater diversity of eukaryotes than previously recognized. A core OTU closely related to Epistylis chrysemydis was identified, and several OTUs were shared by 4–8 libraries. Members of the uncultured lineage LKM11 in Cryptomycota were predominant fungi in sewage treatment processes. This comparative study represents an initial step in furthering understanding of the diversity and role of eukaryotes in sewage treatment processes. PMID:25491751

    7. When Process Mining Meets Bioinformatics R.P. Jagadeesh Chandra Bose1,2

      E-print Network

      van der Aalst, Wil

      mining techniques are able to extract knowledge from such traces and provide a welcome extension construct process models (e.g., Petri nets or BPMN models) from event logs [2]. Discovery is not restricted

    8. EPA'S POLLUTION PREVENTION R&D APPROACHES AND INSIGHTS INTO THECHEMICAL PROCESS INDUSTRY

      EPA Science Inventory

      Chemical Engineers face major research challenges associated withthe imperative to protect and improve the environment. hesechallenges include designing optimal, less polluting chemicalplants and processes, improving air quality through research,managing hazardous wastes responsi...

    9. Contractor relationships and inter-organizational strategies in NASA's R and D acquisition process

      NASA Technical Reports Server (NTRS)

      Guiltinan, J.

      1976-01-01

      Interorganizational analysis of NASA's acquisition process for research and development systems is discussed. The importance of understanding the contractor environment, constraints, and motives in selecting an acquisition strategy is demonstrated. By articulating clear project goals, by utilizing information about the contractor and his needs at each stage in the acquisition process, and by thorough analysis of the inter-organizational relationship, improved selection of acquisition strategies and business practices is possible.

    10. Separation and recovery process R&D to enhance automotive materials recycling

      SciTech Connect

      Daniels, E.J.

      1994-05-01

      Since 1976, the sales-weighted curb-weight of cars and light trucks sold in the United States has decreased by almost 800 pounds. Vehicle weight reduction has, of course, provided for a significant increase in US fleet fuel economy, from 17 to 27 miles per gallon. However, achievement of the weight reduction and concomitant increase in fuel economy was brought about, in part, by the substitution of lighter-weight materials, such as thinner-gauge coated sheet-steels replacing heavy-gauge noncoated sheet-steels and new aluminum alloys replacing steel as well as the increased use of plastics replacing metals. Each of these new materials has created the need for new technology for materials recycling. This paper highlights some of the R&D being conducted at Argonne National Laboratory to develop technology that will enhance and minimize the cost of automotive materials recycling.

    11. Modeling elastic and plastic deformations in nonequilibrium processing using phase field crystals K. R. Elder1

      E-print Network

      Grant, Martin

      Modeling elastic and plastic deformations in nonequilibrium processing using phase field crystals K November 2004) A continuum field theory approach is presented for modeling elastic and plastic deformation the construction of a phase field model for the dynamics of crystal growth that includes elastic and plastic

    12. Latent Process Decomposition of High-Dimensional Count Data Sanvesh Srivastava and R.W. Doerge

      E-print Network

      Figueroa-Lopez, Jose Enrique

      work in groups or processes. The first stage uses a variational empirical Bayesian approach that adapts-dimensional Gaussian data. The second stage of LPD-C selects gene-subsets using empirical Bayes hypothesis testing. Key words: Empirical Bayes; hypothesis testing; hierarchical Bayesian modelling; mixed

    13. Point processes, temporal David R. Brillinger, Peter M. Guttorp & Frederic Paik Schoenberg

      E-print Network

      Schoenberg, Frederic Paik (Rick)

      . The times may correspond to events of several types. Figure 1 presents an example of temporal point process data. The figure actually provides three dif- ferent ways of representing the timing of floods Floods on the Amazon River near Manaus, Brazil, during the years 1892­1992. (a) Amazon floods

    14. FPGA based image processing with R-fuctions and the curvelet transform 

      E-print Network

      Wisinger, John L.

      2003-01-01

      In the past few years, image processing has begun to make its way into many new areas, both academic and commercial. One of the most popular areas is in computer generated animation. This includes films, video games, medical imaging, and various...

    15. The crystal structure of Mtr4 reveals a novel arch domain required for rRNA processing

      SciTech Connect

      Jackson, R.N.; Robinson, H.; Klauer, A. A.; Hintze, B. J.; van Hoof, A.; Johnson, S. J.

      2010-07-01

      The essential RNA helicase, Mtr4, performs a critical role in RNA processing and degradation as an activator of the nuclear exosome. The molecular basis for this vital function is not understood and detailed analysis is significantly limited by the lack of structural data. In this study, we present the crystal structure of Mtr4. The structure reveals a new arch-like domain that is specific to Mtr4 and Ski2 (the cytosolic homologue of Mtr4). In vivo and in vitro analyses demonstrate that the Mtr4 arch domain is required for proper 5.8S rRNA processing, and suggest that the arch functions independently of canonical helicase activity. In addition, extensive conservation along the face of the putative RNA exit site highlights a potential interface with the exosome. These studies provide a molecular framework for understanding fundamental aspects of helicase function in exosome activation, and more broadly define the molecular architecture of Ski2-like helicases.

    16. hUTP24 is essential for processing of the human rRNA precursor at site A1, but not at site A0.

      PubMed

      Tomecki, Rafal; Labno, Anna; Drazkowska, Karolina; Cysewski, Dominik; Dziembowski, Andrzej

      2015-09-01

      Production of ribosomes relies on more than 200 accessory factors to ensure the proper sequence of steps and faultless assembly of ribonucleoprotein machinery. Among trans-acting factors are numerous enzymes, including ribonucleases responsible for processing the large rRNA precursor synthesized by RNA polymerase I that encompasses sequences corresponding to mature 18S, 5.8S, and 25/28S rRNA. In humans, the identity of most enzymes responsible for individual processing steps, including endoribonucleases that cleave pre-rRNA at specific sites within regions flanking and separating mature rRNA, remains largely unknown. Here, we investigated the role of hUTP24 in rRNA maturation in human cells. hUTP24 is a human homolog of the Saccharomyces cerevisiae putative PIN domain-containing endoribonuclease Utp24 (yUtp24), which was suggested to participate in the U3 snoRNA-dependent processing of yeast pre-rRNA at sites A0, A1, and A2. We demonstrate that hUTP24 interacts to some extent with proteins homologous to the components of the yeast small subunit (SSU) processome. Moreover, mutation in the putative catalytic site of hUTP24 results in slowed growth of cells and reduced metabolic activity. These effects are associated with a defect in biogenesis of the 40S ribosomal subunit, which results from decreased amounts of 18S rRNA as a consequence of inaccurate pre-rRNA processing at the 5'-end of the 18S rRNA segment (site A1). Interestingly, and in contrast to yeast, site A0 located upstream of A1 is efficiently processed upon UTP24 dysfunction. Finally, hUTP24 inactivation leads to aberrant processing of 18S rRNA 2 nucleotides downstream of the normal A1 cleavage site. PMID:26237581

    17. Convergence of bi-measure mathbb{R}-trees and the pruning process

      NASA Astrophysics Data System (ADS)

      Löhr, Wolfgang; Voisin, Guillaume; Winter, Anita

      2015-11-01

      In [Aldous,Pitman,1998] a tree-valued Markov chain is derived by pruning off more and more subtrees along the edges of a Galton-Watson tree. More recently, in [Abraham,Delmas,2012], a continuous analogue of the tree-valued pruning dynamics is constructed along L\\'evy trees. In the present paper, we provide a new topology which allows to link the discrete and the continuous dynamics by considering them as instances of the same strong Markov process with different initial conditions. We construct this pruning process on the space of so-called bi-measure trees, which are metric measure spaces with an additional pruning measure. The pruning measure is assumed to be finite on finite trees, but not necessarily locally finite. We also characterize the pruning process analytically via its Markovian generator and show that it is continuous in the initial bi-measure tree. A series of examples is given, which include the finite variance offspring case where the pruning measure is the length measure on the underlying tree.

    18. New Abundance Determinations of Cadmium, Lutetium, and Osmium in the r-process Enriched Star BD+173248

      E-print Network

      Roederer, Ian U; Lawler, James E; Cowan, John J

      2010-01-01

      We report the detection of Cd I (Z = 48), Lu II (Z = 71), and Os II (Z = 76) in the metal-poor star BD+173248. These abundances are derived from an ultraviolet spectrum obtained with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. This is the first detection of these neutron-capture species in a metal-poor star enriched by the r-process. We supplement these measurements with new abundances of Mo I, Ru I, and Rh I derived from an optical spectrum obtained with the High Resolution Echelle Spectrograph on Keck. Combined with previous abundance derivations, 32 neutron-capture elements have been detected in BD+173248, the most complete neutron-capture abundance pattern in any metal-poor star to date. The light neutron-capture elements (38 <= Z <= 48) show a more pronounced even-odd effect than expected from current Solar system r-process abundance predictions. The age for BD+173248 derived from the Th II/Os II chronometer is in better agreement with the age derived from other chronome...

    19. Shelf edge exchange processes-II SEEP2-06, R/V Endeavor cruise 186

      SciTech Connect

      Wilson, C.; Behrens, W.J.; Flagg, C.N.; Wallace, D.W.R.; Wilke, R.J.; Wyman, K.D.

      1989-12-01

      The Shelf Edge Exchange Processes (SEEP) program sponsored by the United States Department of Energy is a multi-institutional effort designed to investigate the flux of suspended material from the continental shelf to the waters of the upper slope, and then possibly into the slope sediments. Phase I of SEEP consisted of a series of nine cruises and a mooring array across the outer continental shelf of New England during 1983--1984. Phase II focused specifically on the shelf/slope frontal region of the mid-Atlantic bight off the Delmarva Peninsula. Hydrographic data were collected on eight of the six cruises.

    20. The Binary Frequency of r-Process-element-enhanced Metal-poor Stars and Its Implications: Chemical Tagging in the Primitive Halo of the Milky Way

      NASA Astrophysics Data System (ADS)

      Hansen, Terese; Andersen, Johannes; Nordström, Birgitta; Buchhave, Lars A.; Beers, Timothy C.

      2011-12-01

      A few rare halo giants in the range [Fe/H] ~= -2.9 ± 0.3 exhibit r-process element abundances that vary as a group by factors up to [r/Fe] ~80, relative to those of the iron peak and below. Yet, the astrophysical production site of these r-process elements remains unclear. We report initial results from four years of monitoring the radial velocities of 17 r-process-enhanced metal-poor giants to detect and characterize binaries in this sample. We find three (possibly four) spectroscopic binaries with orbital periods and eccentricities that are indistinguishable from those of Population I binaries with giant primaries, and which exhibit no signs that the secondary components have passed through the asymptotic giant branch stage of evolution or exploded as supernovae. The other 14 stars in our sample appear to be single—including the prototypical r-process-element-enhanced star CS 22892-052, which is also enhanced in carbon, but not in s-process elements. We conclude that the r-process (and potentially carbon) enhancement of these stars was not a local event due to mass transfer or winds from a binary companion, but was imprinted on the natal molecular clouds of these (single and binary) stars by an external source. These stars are thus spectacular chemical tracers of the inhomogeneous nature of the early Galactic halo system.

    1. Shelf Edge Exchange Processes, II: SEEP2-08, R/V ENDEAVOR cruise 188

      SciTech Connect

      Wilson, C.; Behrens, W.J.; Flagg, C.N.; Wallace, D.W.R.; Wilke, R.J.; Wyman, K.D.

      1989-12-01

      The Shelf Edge Exchange Processes (SEEP) program sponsored by the United States Department of Energy is a multi-institutional effort designed to investigate the flux of suspended material from the continental shelf to the waters of the upper slope, and then possibly into the slope sediments. Phase I of SEEP consisted of a series of nine cruises and a mooring array across the outer continental shelf of New England during 1983--1984 (Behrens and Flagg, 1986). Phase II focused specifically on the shelf/slope frontal region of the mid-Atlantic bight off the Delmarva Peninsula. This project consisted of a series of ten cruises, a mooring array, and a series of over-flights by NASA aircraft. Hydrographic data were collected on eight of the cruises, six of which were primarily mooring deployment or recovery cruises. The cruises were consecutively designated SEEP2-01 to SEEP2-10. Two cruises (SEEP2-04 and SEEP2-07) were dedicated to investigating benthic processes and hydrographic data were not collected.

    2. MOLYBDENUM, RUTHENIUM, AND THE HEAVY r-PROCESS ELEMENTS IN MODERATELY METAL-POOR MAIN-SEQUENCE TURNOFF STARS

      SciTech Connect

      Peterson, Ruth C.

      2013-05-01

      The ratios of elemental abundances observed in metal-poor stars of the Galactic halo provide a unique present-day record of the nucleosynthesis products of its earliest stars. While the heaviest elements were synthesized by the r- and s-processes, dominant production mechanisms of light trans-ironic elements were obscure until recently. This work investigates further our 2011 conclusion that the low-entropy regime of a high-entropy wind (HEW) produced molybdenum and ruthenium in two moderately metal-poor turnoff stars that showed extreme overabundances of those elements with respect to iron. Only a few, rare nucleosynthesis events may have been involved. Here we determine abundances for Mo, Ru, and other trans-Fe elements for 28 similar stars by matching spectral calculations to well-exposed near-UV Keck HIRES spectra obtained for beryllium abundances. In each of the 26 turnoff stars with Mo or Ru line detections and no evidence for s-process production (therefore old), we find Mo and Ru to be three to six times overabundant. In contrast, the maximum overabundance is reduced to factors of three and two for the neighboring elements zirconium and palladium. Since the overproduction peaks sharply at Mo and Ru, a low-entropy HEW is confirmed as its origin. The overabundance level of the heavy r-process elements varies significantly, from none to a factor of four, but is uncorrelated with Mo and Ru overabundances. Despite their moderate metallicity, stars in this group trace the products of different nucleosynthetic events: possibly very few events, possibly events whose output depended on environment, metallicity, or time.

    3. K. S. Telang, R. W. Pike, F. C. Knopf, J. R. Hopper, J. Saleh, S. Waghchoure, S. C. Hedge and T. A. Hertwig,"An Advanced Process Analysis System for Improving Chemical and Refinery Processes," Computers and Chemical Engineering, Vol. 23, p. S727-730 (1999

      E-print Network

      Pike, Ralph W.

      and Chemical Engineering, Vol. 23, p. S727-730 (1999) An Advanced Process Analysis System for Improving. Hertwig,"An Advanced Process Analysis System for Improving Chemical and Refinery Processes," Computers Chemical and Refinery Processes K. S. Telang, X. Chen, R. W. Pike and F. C. Knopf Louisiana State

    4. RRP20, a component of the 90S preribosome, is required for pre-18S rRNA processing in Saccharomyces cerevisiae

      PubMed Central

      Senapin, Saengchan; Desmond Clark-Walker, G.; Jie Chen, Xin; Séraphin, Bertrand; Daugeron, Marie-Claire

      2003-01-01

      A strain of Saccharomyces cerevisiae, defective in small subunit ribosomal RNA processing, has a mutation in YOR145c ORF that converts Gly235 to Asp. Yor145c is a nucleolar protein required for cell viability and has been reported recently to be present in 90S pre-ribosomal particles. The Gly235Asp mutation in YOR145c is found in a KH-type RNA-binding domain and causes a marked deficiency in 18S rRNA production. Detailed studies by northern blotting and primer extension analyses show that the mutant strain impairs the early pre-rRNA processing cleavage essentially at sites A1 and A2, leading to accumulation of a 22S dead-end processing product that is found in only a few rRNA processing mutants. Furthermore, U3, U14, snR10 and snR30 snoRNAs, involved in early pre-rRNA cleavages, are not destabilized by the YOR145c mutation. As the protein encoded by YOR145c is found in pre-ribosomal particles and the mutant strain is defective in ribosomal RNA processing, we have renamed it as RRP20. PMID:12736301

    5. Apollo(R) Thin Film Process Development: Final Technical Report, April 1998 - April 2002

      SciTech Connect

      Cunningham, D.W.

      2002-10-01

      BP Solar first started investigative work on CdTe photovoltaics in 1986. The module product name chosen for the CdTe devices is Apollo. The deposition method chosen was electrochemical deposition due to its simplicity and good control of stoichiometric composition. The window layer used is CdS, produced from a chemical-bath deposition. Initial work focused on increasing photovoltaic cell size from a few mm2 to 900 cm2. At BP Solar's Fairfield plant, work is focused on increasing semiconductor deposition to 1 m2. The primary objective of this subcontract is to establish the conditions required for the efficient plating of CdS/CdTe on large-area, transparent conducting tin-oxide-coated glass superstrate. The initial phase concentrates on superstrate sizes up to 0.55 m2. Later phases will include work on 0.94 m2 superstrates. The tasks in this subcontract have been split into four main categories: (1) CdS and CdTe film studies; (2) Enhanced laser processing; (3) Outdoor testing program for the Apollo module; and (4) Production waste abatement and closed loop study.

    6. Unit operations used to treat process and/or waste streams at nuclear power plants. [R

      SciTech Connect

      Godbee, H.W.; Kibbey, A.H.

      1980-01-01

      Estimates are given of the annual amounts of each generic type of LLW (i.e., Government and commerical (fuel cycle and non-fuel cycle)) that is generated at LWR plants. Many different chemical engineering unit operations used to treat process and/or waste streams at LWR plants include adsorption, evaporation, calcination, centrifugation, compaction, crystallization, drying, filtration, incineration, reverse osmosis, and solidification of waste residues. The treatment of these various streams and the secondary wet solid wastes thus generated is described. The various treatment options for concentrates or solid wet wastes, and for dry wastes are discussed. Among the dry waste treatment methods are compaction, baling, and incineration, as well as chopping, cutting and shredding. Organic materials (liquids (e.g., oils or solvents) and/or solids), could be incinerated in most cases. The filter sludges, spent resins, and concentrated liquids (e.g., evaporator concentrates) are usually solidified in cement, or urea-formaldehyde or unsaturated polyester resins prior to burial. Incinerator ashes can also be incorporated in these binding agents. Asphalt has not yet been used. This paper presents a brief survey of operational experience at LWRs with various unit operations, including a short discussion of problems and some observations on recent trends.

    7. Formerly Used Sites Remedial Action Program (FUSRAP) W. R. Grace Feasibility Study (FS) Alternative Development Process Challenges And Successes

      SciTech Connect

      Fatherly, N.; O'Neill, M.; Glemza, A.

      2008-07-01

      Monazite sand processing was conducted at the W. R. Grace Curtis Bay Facility (Baltimore, Maryland) in the mid 1950's under contract to the Atomic Energy Commission (AEC), for the extraction of source material in the form of thorium, as well as rare earth elements. The processing was conducted in the southwest quadrant of a five-story building (Building 23) in the active manufacturing portion of the facility. Building components and equipment in the southwest quadrant of Building 23 exhibit residual radiological activity remaining from the monazite sand processing. Waste materials from the processing operations (termed gangue) were disposed in the non-manufacturing portion of the facility, in the area referred to the Radioactive Waste Disposal Area (RWDA). Approximately 19,880 cubic meters (m{sup 3}) of radioactive gangue was buried within the RWDA. Waste was believed to be buried at various depths up to 2.7 meters (m), and possibly as deep as 7.6 m. The RI and a supplemental investigation have been completed for the RWDA and adjacent boundary areas. A Feasibility Study (FS) to address residual radioactivity in soils at the RWDA is in the process of being finalized. The chemical-specific Applicable, Relevant, and Appropriate Requirement (ARAR) was selected for the FUSRAP contaminants, and Remedial Goals (RGs) were calculated for the cleanup. The RGs were developed based upon guidance provided in the selected ARAR, 10 Code of Federal Regulations (CFR) 40, Appendix A, Criterion 6(6). This standard is designed to provide an acceptable level of protection to the average member of a critical group who may be exposed to radium in soil for a given scenario. Scenarios, critical group members, and RGs were established in consultation with stakeholders. Dose assessment calculations were performed in accordance with the ARAR to establish derived concentration guideline levels (DCGLs) for each radionuclide in the 232-Thorium ({sup 232}Th) and 238-Uranium ({sup 238}U) chain for both surface and subsurface soils. A sum of the ratios calculation (also called the unity rule) will be utilized (with the DCGLs) to assure compliance with the benchmark doses associated with the radium standards. Six alternatives (including no action) were considered in the FS and included the following technologies: soil washing, segregation, capping/covering, excavation/disposal, and site restrictions. A bench scale study was conducted by USACE to assess the efficacy of soil washing at the site. Results of the study showed reduction of radiological activity in soil. Segregation can be implemented using traditional sampling/analytical routines or automated (gate) segregation and it is likely to reduce the waste stream by at least 30%, while providing a more complete characterization of the soil with a particularly high level of confidence. Challenges for the FS phase of the project included: managing stakeholder input and expectations, defining separate and distinct alternatives for the FS in accordance with the CERCLA process, and selecting the most appropriate ARARs. The challenges were handled successfully, and USACE is finalizing a robust document acceptable to the stakeholders, which will allow USACE to meet the program milestone. In summary: Conducting the W.R. Grace FUSRAP site FUSRAP process has been challenging from a project management perspective, due in part to the nature and extent of impact at the site (residual radioactivity; active processing building and disposal area) and incorporating site owner involvement in the process. Through the use of mediation and mutual commitment to the project by both parties, USACE and the site owner were able to find agreement on fundamental issues and set a firm foundation for achieving successful remedial action and site closure using a 'forward thinking' approach. Currently, USACE is finalizing the RWDA FS to address contamination in soils at the RWDA. ARARs have been identified and selected as per CERCLA guidance. Although obstacles were encountered, the challenges were handled successfully, and USACE is f

    8. Hsa-miR-520d induces hepatoma cells to form normal liver tissues via a stemness-mediated process

      PubMed Central

      Tsuno, Satoshi; Wang, Xinhui; Shomori, Kohei; Hasegawa, Junichi; Miura, Norimasa

      2014-01-01

      The human ncRNA gene RGM249 regulates the extent of differentiation of cancer cells and the conversion of 293FT cells to hiPSCs. To identify the factors underlying this process, we investigated the effects of lentivirally inducing miR-520d expression in 293FT and HLF cells in vitro. Subsequently, we evaluated tumor formation in a xenograft model. Transformed HLF cells were Oct4 and Nanog positive within 24?h, showed p53 upregulation and hTERT downregulation, and mostly lost their migration abilities. After lentiviral infection, the cells were intraperitoneally injected into mice, resulting in benign teratomas (6%), the absence of tumors (87%) or differentiation into benign liver tissues (7%) at the injection site after 1 month. We are the first to demonstrate the loss of malignant properties in cancer cells in vivo through the expression of a single microRNA (miRNA). This miRNA successfully converted 293FT and hepatoma cells to hiPSC-like cells. The regulation of malignancy by miR-520d appears to be through the conversion of cancer cells to normal stem cells, maintaining p53 upregulation. PMID:24458129

    9. Discovery of a strongly r-process enhanced extremely metal-poor star LAMOST J110901.22+075441.8

      E-print Network

      Li, Haining; Honda, Satoshi; Zhao, Gang; Christlieb, Norbert; Suda, Takuma

      2015-01-01

      We report the discovery of an extremely metal-poor (EMP) giant, LAMOST J110901.22+075441.8, which exhibits large excess of r-process elements with [Eu/Fe] ~ +1.16. The star is one of the newly discovered EMP stars identified from LAMOST low-resolution spectroscopic survey and the high-resolution follow-up observation with the Subaru Telescope. Stellar parameters and elemental abundances have been determined from the Subaru spectrum. Accurate abundances for a total of 23 elements including 11 neutron-capture elements from Sr through Dy have been derived for LAMOST J110901.22+075441.8. The abundance pattern of LAMOST J110901.22+075441.8 in the range of C through Zn is in line with the "normal" population of EMP halo stars, except that it shows a notable underabundance in carbon. The heavy element abundance pattern of LAMOST J110901.22+075441.8 is in agreement with other well studied cool r-II metal-poor giants such as CS 22892-052 and CS 31082-001. The abundances of elements in the range from Ba through Dy well...

    10. j : r " , r { ' , : . r ' . ' . r : r ,r , r r r , l\\ , r l r r l i r e V r j r r t " : , \\ , : r t l r r r r i c ,rry'.,n:. ,rii,r r ln( y' r ainQ uallr v-/ t ' lllSAf : / r r

      E-print Network

      Short, Daniel

      a \\i \\/{ t t t , l r , t . j : r " , r { ' , : . r ' . ' . r : r ,r , r r r , l\\ , r l r r l i r e V r j r r t " : , \\ , : r t l r r r r i c ,rry'.,n:. ,rii,r r ln( y' r ainQ uallr v- / t ' lllSAf : / r r I r r , i r . t .l . r r l : / t . 1 : 1 . . [.t.,h',.; r lVr r! L: ( ] . \\ l] r . l) . L: . \\ x

    11. Microbially Augmented Ash and Pyrite Physical Separation (MAAPPS) process R and D: Final technical report

      SciTech Connect

      Not Available

      1988-05-01

      The goal of this project was to develop a novel mechanism to microbially enhance removal of ash and pyrite from coals during flotation. Studies were conducted to: 1) evaluate the attachment of Thiobacillus ferrooxidans to pyrite and ash; 2) optimize the growth of T. ferrooxidans on pyrite enriched process wastes; 3) optimize flotation of three coals with and without microbial pretreatment; 4) demonstrate continuous growth of T. ferrooxidans on tailings; and 5) evaluate cell-free media for pretreatment of coal to reject pyrite and/or ash during flotation. An additional task was undertaken to evaluate the use of T. ferrooxidans in comminution of coal for selective liberation of pyrite and ash. Attachment studies indicated that T. ferrooxidans may attach to pyrite particles, and chemical alteration of pyrite surfaces as well as agglomeration of the pyrite optimization studies indicated that several medium components may be reduced or eliminated when T. ferrooxidans is grown on pyrite tailings. Optimization of the column and froth flotation units resulted in nearly complete removal of liberated pyrite, thus limiting the potential for enhanced removal using microbes. Thus, only marginal selective depression of ash and pyrite occurred when pretreating the coal with T. ferrooxidans. T. ferrooxidans was successfully cultured in a continuous fermentor with production of consistent biomass density, using pyrite enriched tailings. Marginal enhancement of ash and pyrite rejection occurred when pretreating coal with cell-free culture filtrates. Treatment of coal with T. ferrooxidans over a period of days not only resulted in comminution but also in alteration of the characteristics of the coal mixture to achieve better mineral matter and sulfur rejection in some coals. 19 refs., 42 figs., 72 tabs.

    12. Modelling the Glass Press-Blow Process S.M.A. Allaart-Bruin, B.J. van der Linden, and R.M.M. Mattheij

      E-print Network

      Eindhoven, Technische Universiteit

      Modelling the Glass Press-Blow Process S.M.A. Allaart-Bruin, B.J. van der Linden, and R.M.M. Mattheij TUE, CASA, Eindhoven, The Netherlands sbruin@win.tue.nl Summary. For the modelling of the glass- ficulties and is applied. Key words: Level Set Method, glass forming process 1 Introduction A typical stage

    13. A high-entropy-wind r-process study based on nuclear-structure quantities from the new finite-range droplet model FRDM(2012)

      SciTech Connect

      Kratz, Karl-Ludwig; Farouqi, Khalil; Möller, Peter E-mail: kfarouqi@lsw.uni-heidelberg.de

      2014-09-01

      Attempts to explain the source of r-process elements in our solar system (S.S.) by particular astrophysical sites still face entwined uncertainties, stemming from the extrapolation of nuclear properties far from stability, inconsistent sources of different properties (e.g., nuclear masses and ?-decay properties), and the poor understanding of astrophysical conditions, which are hard to disentangle. In this paper we present results from the investigation of r-process in the high-entropy wind (HEW) of core-collapse supernovae (here chosen as one of the possible scenarios for this nucleosynthesis process), using new nuclear-data input calculated in a consistent approach, for masses and ?-decay properties from the new finite-range droplet model FRDM(2012). The accuracy of the new mass model is 0.56 MeV with respect to AME2003, to which it was adjusted. We compare the new HEW r-process abundance pattern to the latest S.S. r-process residuals and to our earlier calculations with the nuclear-structure quantities based on FRDM(1992). Substantial overall and specific local improvements in the calculated pattern of the r-process between A ? 110 and {sup 209}Bi, as well as remaining deficiencies, are discussed in terms of the underlying spherical and deformed shell structure far from stability.

    14. The new model of chemical evolution of r-process elements based on the hierarchical galaxy formation. I. Ba and Eu

      SciTech Connect

      Komiya, Yutaka; Suda, Takuma; Yamada, Shimako; Fujimoto, Masayuki Y.

      2014-03-10

      We investigate the chemical enrichment of r-process elements in the early evolutionary stages of the Milky Way halo within the framework of hierarchical galaxy formation using a semi-analytic merger tree. In this paper, we focus on heavy r-process elements, Ba and Eu, of extremely metal-poor (EMP) stars and give constraints on their astronomical sites. Our models take into account changes of the surface abundances of EMP stars by the accretion of interstellar medium (ISM). We also consider metal-enrichment of intergalactic medium by galactic winds and the resultant pre-enrichment of proto-galaxies. The trend and scatter of the observed r-process abundances are well reproduced by our hierarchical model with ?10% of core-collapse supernovae in low-mass end (?10 M {sub ?}) as a dominant r-process source and the star formation efficiency of ?10{sup –10} yr{sup –1}. For neutron star mergers as an r-process source, their coalescence timescale has to be ?10{sup 7} yr, and the event rates ?100 times larger than currently observed in the Galaxy. We find that the accretion of ISM is a dominant source of r-process elements for stars with [Ba/H] < –3.5. In this model, a majority of stars at [Fe/H] < –3 are formed without r-process elements, but their surfaces are polluted by the ISM accretion. The pre-enrichment affects ?4% of proto-galaxies, and yet, is surpassed by the ISM accretion in the surface of EMP stars.

    15. Parallel processing of real-time dynamic systems simulation on OSCAR (Optimally SCheduled Advanced multiprocessoR)

      NASA Technical Reports Server (NTRS)

      Kasahara, Hironori; Honda, Hiroki; Narita, Seinosuke

      1989-01-01

      Parallel processing of real-time dynamic systems simulation on a multiprocessor system named OSCAR is presented. In the simulation of dynamic systems, generally, the same calculation are repeated every time step. However, we cannot apply to Do-all or the Do-across techniques for parallel processing of the simulation since there exist data dependencies from the end of an iteration to the beginning of the next iteration and furthermore data-input and data-output are required every sampling time period. Therefore, parallelism inside the calculation required for a single time step, or a large basic block which consists of arithmetic assignment statements, must be used. In the proposed method, near fine grain tasks, each of which consists of one or more floating point operations, are generated to extract the parallelism from the calculation and assigned to processors by using optimal static scheduling at compile time in order to reduce large run time overhead caused by the use of near fine grain tasks. The practicality of the scheme is demonstrated on OSCAR (Optimally SCheduled Advanced multiprocessoR) which has been developed to extract advantageous features of static scheduling algorithms to the maximum extent.

    16. Molybdenum, Ruthenium, and the Heavy r-process Elements in Moderately Metal-Poor Main-Sequence Turnoff Stars

      E-print Network

      Peterson, Ruth C

      2013-01-01

      The ratios of elemental abundances observed in metal-poor stars of the Galactic halo provide a unique present-day record of the nucleosynthesis products of its earliest stars. While the heaviest elements were synthesized by the r- and s-processes, dominant production mechanisms of light trans-ironic elements were obscure until recently. This work investigates further our 2011 conclusion that the low-entropy regime of a high-entropy wind (HEW) produced molybdenum and ruthenium in two moderately metal-poor turnoff stars that showed extreme overabundances of those elements with respect to iron. Only a few, rare nucleosynthesis events may have been involved. Here we determine abundances for Mo, Ru, and other trans-Fe elements for 28 similar stars by matching spectral calculations to well-exposed near-UV Keck HIRES spectra obtained for beryllium abundances. In each of the 26 turnoff stars with Mo or Ru line detections and no evidence for s-process production (therefore old), we find Mo and Ru to be three to six ti...

    17. Explosive Nucleosynthesis of Weak r-Process Elements in Extremely Metal-Poor Core-Collapse Supernovae

      E-print Network

      N. Izutani; H. Umeda; N. Tominaga

      2008-10-31

      There have been attempts to fit the abundance patterns of extremely metal-poor stars with supernova nucleosynthesis models for the lighter elements than Zn. On the other hand, observations have revealed that the presence of EMP stars with peculiarly high ratio of "weak r-process elements" Sr, Y and Zr. Although several possible processes were suggested for the origin of these elements, the complete solution for reproducing those ratios is not found yet. In order to reproduce the abundance patterns of such stars, we investigate a model with neutron rich matter ejection from the inner region of the conventional mass-cut. We find that explosive nucleosynthesis in a high energy supernova (or "hypernova") can reproduce the high abundances of Sr, Y and Zr but that the enhancements of Sr, Y and Zr are not achieved by nucleosynthesis in a normal supernova. Our results imply that, if these elements are ejected from a normal supernova, nucleosynthesis in higher entropy flow than that of the supernova shock is required.

    18. ?-Decay Half-Lives of 110 Neutron-Rich Nuclei across the N=82 Shell Gap: Implications for the Mechanism and Universality of the Astrophysical r Process.

      PubMed

      Lorusso, G; Nishimura, S; Xu, Z Y; Jungclaus, A; Shimizu, Y; Simpson, G S; Söderström, P-A; Watanabe, H; Browne, F; Doornenbal, P; Gey, G; Jung, H S; Meyer, B; Sumikama, T; Taprogge, J; Vajta, Zs; Wu, J; Baba, H; Benzoni, G; Chae, K Y; Crespi, F C L; Fukuda, N; Gernhäuser, R; Inabe, N; Isobe, T; Kajino, T; Kameda, D; Kim, G D; Kim, Y-K; Kojouharov, I; Kondev, F G; Kubo, T; Kurz, N; Kwon, Y K; Lane, G J; Li, Z; Montaner-Pizá, A; Moschner, K; Naqvi, F; Niikura, M; Nishibata, H; Odahara, A; Orlandi, R; Patel, Z; Podolyák, Zs; Sakurai, H; Schaffner, H; Schury, P; Shibagaki, S; Steiger, K; Suzuki, H; Takeda, H; Wendt, A; Yagi, A; Yoshinaga, K

      2015-05-15

      The ?-decay half-lives of 110 neutron-rich isotopes of the elements from _{37}Rb to _{50}Sn were measured at the Radioactive Isotope Beam Factory. The 40 new half-lives follow robust systematics and highlight the persistence of shell effects. The new data have direct implications for r-process calculations and reinforce the notion that the second (A?130) and the rare-earth-element (A?160) abundance peaks may result from the freeze-out of an (n,?)?(?,n) equilibrium. In such an equilibrium, the new half-lives are important factors determining the abundance of rare-earth elements, and allow for a more reliable discussion of the r process universality. It is anticipated that universality may not extend to the elements Sn, Sb, I, and Cs, making the detection of these elements in metal-poor stars of the utmost importance to determine the exact conditions of individual r-process events. PMID:26024165

    19. p-SMAD2/3 and DICER promote pre-miR-21 processing during pressure overload-associated myocardial remodeling.

      PubMed

      García, Raquel; Nistal, J Francisco; Merino, David; Price, Nathan L; Fernández-Hernando, Carlos; Beaumont, Javier; González, Arantxa; Hurlé, María A; Villar, Ana V

      2015-07-01

      Transforming growth factor-? (TGF-?) induces miR-21 expression which contributes to fibrotic events in the left ventricle (LV) under pressure overload. SMAD effectors of TGF-? signaling interact with DROSHA to promote primary miR-21 processing into precursor miR-21 (pre-miR-21). We hypothesize that p-SMAD-2 and -3 also interact with DICER1 to regulate the processing of pre-miR-21 to mature miR-21 in cardiac fibroblasts under experimental and clinical pressure overload. The subjects of the study were mice undergoing transverse aortic constriction (TAC) and patients with aortic stenosis (AS). In vitro, NIH-3T3 fibroblasts transfected with pre-miR-21 responded to TGF-?1 stimulation by overexpressing miR-21. Overexpression and silencing of SMAD2/3 resulted in higher and lower production of mature miR-21, respectively. DICER1 co-precipitated along with SMAD2/3 and both proteins were up-regulated in the LV from TAC-mice. Pre-miR-21 was isolated bound to the DICER1 maturation complex. Immunofluorescence analysis revealed co-localization of p-SMAD2/3 and DICER1 in NIH-3T3 and mouse cardiac fibroblasts. DICER1-p-SMAD2/3 protein-protein interaction was confirmed by in situ proximity ligation assay. Myocardial up-regulation of DICER1 constituted a response to pressure overload in TAC-mice. DICER mRNA levels correlated directly with those of TGF-?1, SMAD2 and SMAD3. In the LV from AS patients, DICER mRNA was up-regulated and its transcript levels correlated directly with TGF-?1, SMAD2, and SMAD3. Our results support that p-SMAD2/3 interacts with DICER1 to promote pre-miR-21 processing to mature miR-21. This new TGF?-dependent regulatory mechanism is involved in miR-21 overexpression in cultured fibroblasts, and in the pressure overloaded LV of mice and human patients. PMID:25887159

    20. Kinetic Phases in the Electron Transfer from P+ Associated Processes in Rhodobacter sphaeroides R-26 Reaction Centers

      E-print Network

      Gunner, Marilyn

      in Rhodobacter sphaeroides R-26 Reaction Centers Jiali Li, Dan Gilroy, David M. Tiede,§ and M. R. Gunner to form P+QAQB - was measured in Rhodobacter sphaeroides R-26 reaction centers (RCs) where the native primary quinone, ubiquinone-10 (UQA), was replaced by 2-methyl-3-phytyl-1,4-naphthoquinone (MQA

    1. PUBLICATIONS --BOOKS Rhodes, O. E., R. K. Chesser, and M. H. Smith (eds). 1996. Population Processes in Ecological Space

      E-print Network

      Chesser, Ronald Keith

      , R. K. 1983. Genetic variability within and among populations of the black-tailed prairie dog. Evolution 37:320-331. Chesser, R. K. 1983. Cranial variation among populations of the black-tailed prairie dog in New Mexico. Occas. Papers Mus., Texas Tech Univ. 84:1-13. Chesser, R. K. 1983. Isolation

    2. STAT3-regulated exosomal miR-21 promotes angiogenesis and is involved in neoplastic processes of transformed human bronchial epithelial cells.

      PubMed

      Liu, Yi; Luo, Fei; Wang, Bairu; Li, Huiqiao; Xu, Yuan; Liu, Xinlu; Shi, Le; Lu, Xiaolin; Xu, Wenchao; Lu, Lu; Qin, Yu; Xiang, Quanyong; Liu, Qizhan

      2016-01-01

      Although microRNA (miRNA) enclosed in exosomes can mediate intercellular communication, the roles of exosomal miRNA and angiogenesis in lung cancer remain unclear. We investigated functions of STAT3-regulated exosomal miR-21 derived from cigarette smoke extract (CSE)-transformed human bronchial epithelial (HBE) cells in the angiogenesis of CSE-induced carcinogenesis. miR-21 levels in serum were higher in smokers than those in non-smokers. The medium from transformed HBE cells promoted miR-21 levels in normal HBE cells and angiogenesis of human umbilical vein endothelial cells (HUVEC). Transformed cells transferred miR-21 into normal HBE cells via exosomes. Knockdown of STAT3 reduced miR-21 levels in exosomes derived from transformed HBE cells, which blocked the angiogenesis. Exosomes derived from transformed HBE cells elevated levels of vascular endothelial growth factor (VEGF) in HBE cells and thereby promoted angiogenesis in HUVEC cells. Inhibition of exosomal miR-21, however, decreased VEGF levels in recipient cells, which blocked exosome-induced angiogenesis. Thus, miR-21 in exosomes leads to STAT3 activation, which increases VEGF levels in recipient cells, a process involved in angiogenesis and malignant transformation of HBE cells. These results, demonstrating the function of exosomal miR-21 from transformed HBE cells, provide a new perspective for intervention strategies to prevent carcinogenesis of lung cancer. PMID:26525579

    3. X-ray decay lines from heavy nuclei in supernova remnants as a probe of the r-process origin and the birth periods of magnetars

      NASA Astrophysics Data System (ADS)

      Ripley, Justin L.; Metzger, Brian D.; Arcones, Almudena; Martínez-Pinedo, Gabriel

      2014-03-01

      The origin of rapid neutron capture (r-process) nuclei remains one of the longest standing mysteries in nuclear astrophysics. Core collapse supernovae (SNe) and neutron star binary mergers are likely r-process sites, but little evidence yet exists for their in situ formation in such environments. Motivated by the advent of sensitive new or planned X-ray telescopes such as the Nuclear Spectroscopic Telescope Array (NuSTAR) and the Large Observatory for X-ray Timing (LOFT), we revisit the prospects for the detection of X-ray decay lines from r-process nuclei in young or nearby supernova remnants. For all remnants planned to be observed by NuSTAR (and several others), we conclude that r-process nuclei are detectable only if the remnant possesses a large overabundance O ? 10^3 relative to the average yield per SN. Prospects are better for the next Galactic SN (assumed age of 3 yr and distance of 10 kpc), for which an average r-process yield is detectable via the 10.7 (9.2) keV line complexes of 194Os by LOFT at 6? (5?) confidence; the 27.3 keV line complex of 125Sb is detectable by NuSTAR at 2? for O ? 2. We also consider X-rays lines from the remnants of Galactic magnetars, motivated by the much higher r-process yields of the magnetorotationally driven SNe predicted to birth magnetars. The ˜3.6-3.9 keV lines of 126Sn are potentially detectable in the remnants of the magnetars 1E1547.0-5408 and 1E2259+586 by LOFT for an assumed r-process yield predicted by recent simulations. The (non-)detection of these lines can thus probe whether magnetars are indeed born with millisecond periods. Finally, we consider a blind survey of the Galactic plane with LOFT for r-process lines from the most recent binary neutron star merger remnant, concluding that a detection is unlikely without additional information on the merger location.

    4. Transcript-based Cloning of RRP46, a Regulator of rRNA Processing and R-Gene-Independent Cell Death in Barley–Powdery Mildew Interactions

      Technology Transfer Automated Retrieval System (TEKTRAN)

      Programmed cell death (PCD) plays a pivotal role in plant development and defense. To investigate the degree of interaction between PCD and R-gene mediated defense, we used the 22K Barley1 GeneChip to compare and contrast time-course expression profiles of Blumeria graminis f. sp. hordei (Bgh) chal...

    5. Kilonovae: Electromagnetic Counterparts of Neutron Star Mergers Powered by the Radioactive Decay of R-Process Nuclei

      NASA Astrophysics Data System (ADS)

      Metzger, Brian

      2014-03-01

      The coalescence of binary neutron stars (NSs) are the most promising sources for the direct detection of gravitational waves by Advanced LIGO and Virgo. However, maximizing the scientific opportunities from such a discovery will require the detection of a coincident electromagnetic counterpart. One possible counterpart is a short gamma-ray burst (GRB), powered by the accretion of NS debris left over from the merger onto the newly-formed black hole. However, GRBs are thought to be relativistically beamed and hence to accompany only a small fraction of mergers. NS mergers also produce isotropic supernova-like emission, powered by the radioactive decay of heavy (r-process) elements which are synthesized in the neutron-rich ejecta from the merger. I will describe the first calculations of such ``kilonovae'' which include realistic nuclear physics and radiative transport. In addition to providing a smoking gun for detecting binary NS mergers, kilonovae inform the unknown origin of the heaviest elements in the Universe. The first kilonova may have been discovered by the Hubble Space Telescope last year.

    6. Short-lived $^{244}$Pu Points to Compact Binary Mergers as Sites for Heavy r-process Nucleosynthesis

      E-print Network

      Hotokezaka, Kenta; Paul, Michael

      2015-01-01

      Measurements of the radioactive $^{244}$Pu abundances can break the degeneracy between high-rate/low-yield and low-rate/high-yield scenarios for the production of heavy $r$-process elements. The first corresponds to production by core collapse supernovae (cc-SNe) while the latter corresponds to production by e.g. compact binary mergers. The estimated $^{244}$Pu abundance in the current interstellar medium inferred from deep-sea measurements (Wallner et al. 2015) is significantly lower than that corresponding Early Solar System abundances (Turner et al 2007). We estimate the expected median value of the $^{244}$Pu abundances and fluctuations around this value in both models. We show that while the current and Early Solar System abundances are naturally explained within the low-rate/high-yield (e.g. merger) scenario, they are incompatible with the high-rate/low-yield (cc-SNe) model. The inferred event rate remarkably agrees with compact binary merger rates estimated from Galactic neutron star binaries and from ...

    7. S2P3-R (v1.0): a framework for efficient regional modelling of physical and biological structures and processes in shelf seas

      NASA Astrophysics Data System (ADS)

      Marsh, R.; Hickman, A. E.; Sharples, J.

      2015-10-01

      An established one-dimensional (1-D) model of Shelf Sea Physics and Primary Production (S2P3) is adapted for flexible use in selected regional settings over selected periods of time. This Regional adaptation of S2P3, the S2P3-R framework (v1.0), can be efficiently used to investigate physical and biological phenomena in shelf seas that are strongly controlled by vertical processes. These include spring blooms that follow the onset of stratification, tidal mixing fronts that seasonally develop at boundaries between mixed and stratified water, and sub-surface chlorophyll maxima that persist throughout summer. While not representing 3-D processes, S2P3-R reveals the horizontal variation of the key 1-D (vertical) processes. S2P3-R should therefore only be used in regions where horizontal processes - including mean flows, eddy fluxes and internal tides - are known to exert a weak influence in comparison with vertical processes. In such cases, S2P3-R may be used as a highly versatile research tool, alongside more complex and computationally expensive models. In undergraduate oceanography modules and research projects, the model serves as an effective practical tool for linking theory and field observations. Three different regional configurations of S2P3-R are described, illustrating a range of diagnostics, evaluated where practical with observations. The model can be forced with daily meteorological variables for any selected year in the reanalysis era (1948 onwards). Example simulations illustrate the considerable extent of synoptic-to-interannual variability in the physics and biology of shelf seas. In discussion, the present limitations of S2P3-R are emphasised, and future developments are outlined.

    8. Components of the nucleolar processing complex (Pre-rRNA, fibrillarin, and nucleolin) colocalize during mitosis and are incorporated to daughter cell nucleoli.

      PubMed

      Medina, F J; Cerdido, A; Fernández-Gómez, M E

      1995-11-01

      We have traced in onion root cells the mitotic course of rRNA, of the RNA synthesized in the G2 period of the preceding interphase, and of the nucleolar proteins fibrillarin and nucleolin. The rRNA was detected by ultrastructural in situ hybridization with a rDNA probe capable of hybridizing mature rRNAs and also the intermediate forms of pre-rRNA processing. The RNA synthesized in the preceding G2 (which, according to classical data, is mostly rRNA) was revealed by autoradiography on synchronous cells labeled in G2 by tritiated uridine. Fibrillarin was detected by immunofluorescence in both mammalian and onion cells; the results in the latter cells were compared with those obtained after AgNOR staining. Electron microscopical immunocytochemistry was used to detect fibrillarin and nucleolin in onion cells. In all cases, following nucleolar dispersion in prophase, the signal was detected in the chromosome periphery during metaphase and anaphase, in irregular fibrillar masses located between chromosomes in ana-telophase, in prenucleolar bodies during telophase, and in the newly formed nucleoli, after nucleologenesis. Moreover, as expected, ribosomes appeared labeled after in situ hybridization, but a dispersed cytoplasmic labeling was observed in all experiments, mainly during metaphase and anaphase. These results demonstrate that nucleolar components involved in pre-rRNA processing, including rRNA itself, probably in an incompletely processed form, are transferred from the parental to the daughter cell nucleoli by means of transient structures, such as the perichromosomal sheath and prenucleolar bodies. Since these macromolecular components are assembled in the interphase nucleolus, forming the RNP processing complex, their colocalization during mitosis in the same transient structures strongly suggests that at least a subset of these complexes does not disaggregate during cell division, but remains assembled and becomes incorporated to the new nucleolus. Therefore, ribosome biogenesis restarts not only after mitosis at the level of transcription, but also at the intermediate levels of pre-rRNA processing. PMID:7589236

    9. Beta-decay of nuclei around Se-90. Search for signatures of a N=56 sub-shell closure relevant the r-process

      E-print Network

      M. Quinn; A. Aprahamian; J. Pereira; R. Surman; O. Arndt; T. Baumann; A. Becerril; T. Elliot; A. Estrade; D. Galaviz; T. Ginter; M. Hausmann; S. Hennrich; R. Kessler; K. -L. Kratz; G. Lorusso; P. F. Mantica; M. Matos; P. Moller; F. Montes; B. Pfeiffer; M. Portillo; S. Hennrich; H. Schatz; F. Schertz; L. Schnorrenberger; E. Smith; A. Stolz; W. B. Walters; A. Wohr

      2011-12-21

      Nuclear structure plays a significant role on the rapid neutron capture process (r-process) since shapes evolve with the emergence of shells and sub-shells. There was some indication in neighboring nuclei that we might find examples of a new N=56 sub-shell, which may give rise to a doubly magic Se-90 nucleus. Beta-decay half lives of nuclei around Se-90 have been measured to determine if this nucleus has in fact a doubly-magic character. The fragmentation of Xe-136 beam at the National Superconducting Cyclotron Laboratory at Michigan State University was used to create a cocktail of nuclei in the A=90 region. We have measured the half lives of twenty-two nuclei near the r-process path in the A=90 region. The half lives of As-88 and Se-90 have been measured for the first time. The values were compared with theoretical predictions in the search for nuclear-deformation signatures of a N=56 sub-shell, and its possible role in the emergence of a potential doubly-magic Se-90. The impact of such hypothesis on the synthesis of heavy nuclei, particularly in the production of Sr, Y and Zr elements was investigated with a weak r-process network. The new half lives agree with results obtained from a standard global QRPA model used in r-process calculations, indicating that Se-90 has a quadrupole shape incompatible with a closed N=56 sub-shell in this region. The impact of the measured Se-90 half-life in comparison with a former theoretical predication associated with a spherical half-life on the weak-r-process is shown to be strong.

    10. The cytosol-synthesized subunit II (Cox2) precursor with the point mutation W56R is correctly processed in yeast mitochondria to rescue cytochrome oxidase.

      PubMed

      Cruz-Torres, Valentín; Vázquez-Acevedo, Miriam; García-Villegas, Rodolfo; Pérez-Martínez, Xochitl; Mendoza-Hernández, Guillermo; González-Halphen, Diego

      2012-12-01

      Deletion of the yeast mitochondrial gene COX2 encoding subunit 2 (Cox2) of cytochrome c oxidase (CcO) results in loss of respiration (?cox2 strain). Supekova et al. (2010) [1] transformed a ?cox2 strain with a vector expressing Cox2 with a mitochondrial targeting sequence (MTS) and the point mutation W56R (Cox2(W56R)), restoring respiratory growth. Here, the CcO carrying the allotopically-expressed Cox2(W56R) was characterized. Yeast mitochondria from the wild-type (WT) and the ?cox2+Cox2(W56R) strains were subjected to Blue Native electrophoresis. In-gel activity of CcO and spectroscopic quantitation of cytochromes revealed that only 60% of CcO is present in the complemented strain, and that less CcO is found associated in supercomplexes as compared to WT. CcOs from the WT and the mutant exhibited similar subunit composition, although activity was 20-25% lower in the enzyme containing Cox2(W56R) than in the one with Cox2(WT). Tandem mass spectrometry confirmed that W(56) was substituted by R(56) in Cox2(W56R). In addition, Cox2(W56R) exhibited the same N-terminus than Cox2(WT), indicating that the MTS of Oxa1 and the leader sequence of 15 residues were removed from Cox2(W56R) during maturation. Thus, Cox2(W56R) is identical to Cox2(WT) except for the point mutation W56R. Mitochondrial Cox1 synthesis is strongly reduced in ?cox2 mutants, but the Cox2(W56R) complemented strain led to full restoration of Cox1 synthesis. We conclude that the cytosol-synthesized Cox2(W56R) follows a rate-limiting process of import, maturation or assembly that yields lower steady-state levels of CcO. Still, the allotopically-expressed Cox2(W56R) restores CcO activity and allows mitochondrial Cox1 synthesis to advance at WT levels. PMID:22985601

    11. Paper No. ICETECH14-162-R1 Tijsen Page number: 1 Use of thermal imagery to assess temperature variation in ice collision processes

      E-print Network

      Bruneau, Steve

      Paper No. ICETECH14-162-R1 Tijsen Page number: 1 Use of thermal imagery to assess temperature of thermal imagery on ice collisional processes. This way of measuring provides a new source of information provides some observations, however the main purpose is to show the value of applying thermal imagery

    12. Shedding new Light on Fog Physical Processes By m. Haeffelin, t. Bergot, t. elias, r. tardif, d. Carrer, p. CHaZette, m. ColomB,

      E-print Network

      PARISFOG Shedding new Light on Fog Physical Processes By m. Haeffelin, t. Bergot, t. elias, rCiare, and X. ZHang A field experiment covering more than 100 fog and near-fog situations during the winter of fog. L ow-visibility meteorological conditions, such as fog, are not necessarily considered extreme

    13. Improved Laboratory Transition Probabilities for Er II and Applications to the Erbium Abundances of the Sun and Five r-Process Rich, Metal-Poor Stars

      E-print Network

      J. E. Lawler; C. Sneden; J. J. Cowan; J. -F. Wyart; I. I. Ivans; J. S. Sobeck; M. H. Stockett; E. A. Den Hartog

      2008-04-28

      Recent radiative lifetime measurements accurate to +/- 5% (Stockett et al. 2007, J. Phys. B 40, 4529) using laser-induced fluorescence (LIF) on 8 even-parity and 62 odd-parity levels of Er II have been combined with new branching fractions measured using a Fourier transform spectrometer (FTS) to determine transition probabilities for 418 lines of Er II. This work moves Er II onto the growing list of rare earth spectra with extensive and accurate modern transition probability measurements using LIF plus FTS data. This improved laboratory data set has been used to determine a new solar photospheric Er abundance, log epsilon = 0.96 +/- 0.03 (sigma = 0.06 from 8 lines), a value in excellent agreement with the recommended meteoric abundance, log epsilon = 0.95 +/- 0.03. Revised Er abundances have also been derived for the r-process-rich metal-poor giant stars CS 22892-052, BD+17 3248, HD 221170, HD 115444, and CS 31082-001. For these five stars the average Er/Eu abundance ratio, = 0.42, is in very good agreement with the solar-system r-process ratio. This study has further strengthened the finding that r-process nucleosynthesis in the early Galaxy which enriched these metal-poor stars yielded a very similar pattern to the r-process which enriched later stars including the Sun.

    14. The Revised Two-Factor Study Process Questionnaire (R-SPQ-2F): Exploratory and Confirmatory Factor Analyses at Item Level

      ERIC Educational Resources Information Center

      Justicia, Fernando; Pichardo, M. Carmen; Cano, Francisco; Berben, A. B. G.; De la Fuente, Jesus

      2008-01-01

      The underlying structure of the Revised Two Factor version of the Study Process Questionnaire (R-SPQ-2F), a 20-item instrument for the evaluation of students' approaches to learning (SAL), was examined at item level using two independent groups of undergraduate students enrolled in the first (n = 314) and last (n = 522) years of their studies. The…

    15. Modeling of Casting, Welding and Advanced Solidification Processes IX Edited by Peter R. Sahm, Preben N. Hansen and James G. Conley

      E-print Network

      Taylor, Gary

      Modeling of Casting, Welding and Advanced Solidification Processes IX Edited by Peter R. Sahm to the Modelling of Welding Phenomena G. A. Taylor, M. Hughes and K. Pericleous Centre for Numerical Modelling of welding phenomena is presented. The framework includes models from both the fields of Computational Fluid

    16. Bop1 Is a Mouse WD40 Repeat Nucleolar Protein Involved in 28S and 5.8S rRNA Processing and 60S Ribosome Biogenesis

      PubMed Central

      Strezoska, Žaklina; Pestov, Dimitri G.; Lau, Lester F.

      2000-01-01

      We have identified and characterized a novel mouse protein, Bop1, which contains WD40 repeats and is highly conserved through evolution. bop1 is ubiquitously expressed in all mouse tissues examined and is upregulated during mid-G1 in serum-stimulated fibroblasts. Immunofluorescence analysis shows that Bop1 is localized predominantly to the nucleolus. In sucrose density gradients, Bop1 from nuclear extracts cosediments with the 50S-80S ribonucleoprotein particles that contain the 32S rRNA precursor. RNase A treatment disrupts these particles and releases Bop1 into a low-molecular-weight fraction. A mutant form of Bop1, Bop1?, which lacks 231 amino acids in the N- terminus, is colocalized with wild-type Bop1 in the nucleolus and in ribonucleoprotein complexes. Expression of Bop1? leads to cell growth arrest in the G1 phase and results in a specific inhibition of the synthesis of the 28S and 5.8S rRNAs without affecting 18S rRNA formation. Pulse-chase analyses show that Bop1? expression results in a partial inhibition in the conversion of the 36S to the 32S pre-rRNA and a complete inhibition of the processing of the 32S pre-rRNA to form the mature 28S and 5.8S rRNAs. Concomitant with these defects in rRNA processing, expression of Bop1? in mouse cells leads to a deficit in the cytosolic 60S ribosomal subunits. These studies thus identify Bop1 as a novel, nonribosomal mammalian protein that plays a key role in the formation of the mature 28S and 5.8S rRNAs and in the biogenesis of the 60S ribosomal subunit. PMID:10891491

    17. Ozonation attenuates the steroidogenic disruptive effects of sediment free oil sands process water in the H295R cell line.

      PubMed

      He, Yuhe; Wiseman, Steve B; Zhang, Xiaowei; Hecker, Markus; Jones, Paul D; El-Din, Mohamed Gamal; Martin, Jonathan W; Giesy, John P

      2010-07-01

      There is concern regarding oil sands process water (OSPW) produced by the oil sands industry in Alberta, Canada. Little is known about the potential for OSPW, and naphthenic acids (NAs), which are the primary persistent and toxic constituents of OSPW, to affect endocrine systems. Although ozonation significantly reduces concentrations of NAs and OSPW toxicity, it was hypothesized that oxidation of OSPW might produce hydroxylated products with steroidogenic activity. Therefore, untreated and ozone treated OSPW were examined for effects on sex steroid production using the H295R Steroidogenesis Assay. Untreated OSPW significantly decreased testosterone (T) and increased 17beta-estradiol (E2) concentrations at OSPW dilutions greater or equal to 10-fold. This effect was mainly due to decreased E2 metabolism. Analysis of CYP19A (aromatase) mRNA abundance and enzyme activity suggested that induction of this enzyme activity may have also contributed to these effects. Reduction of parent NA concentrations by 24% or 85% decreased the effect of OSPW on E2 production. Although T production remained significantly reduced in cells exposed to ozone treated OSPW, the effect was diminished. Aromatase mRNA abundance and enzyme activity were significantly greater in cells exposed to ozone treated OSPW, however the magnitude was less than in cells exposed to untreated OSPW. No change of E2 metabolism was observed in cells exposed to ozone treated OSPW, which may account for recovery of E2 levels. The results indicate that OSPW exposure can decrease E2 and T production, but ozonation is an effective treatment to reduce NA concentrations in OSPW without increasing affects on steroidogenesis. PMID:20466405

    18. Two splicing factors carrying serine-arginine motifs, TSR1 and TSR1IP, regulate splicing, mRNA stability, and rRNA processing in Trypanosoma brucei

      PubMed Central

      Gupta, Sachin Kumar; Chikne, Vaibhav; Eliaz, Dror; Tkacz, Itai Dov; Naboishchikov, Ilana; Carmi, Shai; Waldman Ben-Asher, Hiba; Michaeli, Shulamit

      2014-01-01

      In trypanosomes, mRNAs are processed by trans-splicing; in this process, a common exon, the spliced leader, is added to all mRNAs from a small RNA donor, the spliced leader RNA (SL RNA). However, little is known regarding how this process is regulated. In this study, we investigated the function of two serine-arginine-rich proteins, TSR1 and TSR1IP, implicated in trans-splicing in Trypanosoma brucei. Depletion of these factors by RNAi suggested their role in both cis- and trans-splicing. Microarray was used to examine the transcriptome of the silenced cells. The level of hundreds of mRNAs was changed, suggesting that these proteins have a role in regulating only a subset of T. brucei mRNAs. Mass-spectrometry analyses of complexes associated with these proteins suggest that these factors function in mRNA stability, translation, and rRNA processing. We further demonstrate changes in the stability of mRNA as a result of depletion of the two TSR proteins. In addition, rRNA defects were observed under the depletion of U2AF35, TSR1, and TSR1IP, but not SF1, suggesting involvement of SR proteins in rRNA processing. PMID:24922194

    19. We are using both space-based (Hubble Space Telescope, HST) and ground-based telescopes to make extensive studies of Galactic halo stars. These stars contain nucleosynthesis products (from the rapid neutron capture process, r-process) from the

      E-print Network

      Cowan, John

      to make extensive studies of Galactic halo stars. These stars contain nucleosynthesis products (from Galactic r-process nucleosynthesis. These in turn will help to identify the characteristics and nature ­ particularly the sites and the astrophysical conditions for their formation EARLY GALACTIC NUCLEOSYNTHESIS

    20. A Novel “Oxygen-induced” Greening Process in a Cyanobacterial Mutant Lacking the Transcriptional Activator ChlR Involved in Low-oxygen Adaptation of Tetrapyrrole Biosynthesis*

      PubMed Central

      Aoki, Rina; Hiraide, Yuto; Yamakawa, Hisanori; Fujita, Yuichi

      2014-01-01

      ChlR activates the transcription of the chlAII-ho2-hemN operon in response to low-oxygen conditions in the cyanobacterium Synechocystis sp. PCC 6803. Three genes in the operon encode low-oxygen-type enzymes to bypass three oxygen-dependent reactions in tetrapyrrole biosynthesis. A chlR-lacking mutant, ?chlR, shows poor photoautotrophic growth due to low chlorophyll (Chl) content under low-oxygen conditions, which is caused by no induction of the operon. Here, we characterized the processes of etiolation of ?chlR cells in low-oxygen conditions and the subsequent regreening of the etiolated cells upon exposure to oxygen, by HPLC, Western blotting, and low-temperature fluorescence spectra. The Chl content of the etiolated ?chlR cells incubated under low-oxygen conditions for 7 days was only 10% of that of the wild-type with accumulation of almost all intermediates of the magnesium branch of Chl biosynthesis. Both photosystem I (PSI) and photosystem II (PSII) were significantly decreased, accompanied by a preferential decrease of antenna Chl in PSI. Upon exposure to oxygen, the etiolated ?chlR cells resumed to produce Chl after a short lag (?2 h), and the level at 72 h was 80% of that of the wild-type. During this novel “oxygen-induced” greening process, the PSI and PSII contents were largely increased in parallel with the increase in Chl contents. After 72 h, the PSI content reached ?50% of the wild-type level in contrast to the full recovery of PSII. ?chlR provides a promising alternative system to investigate the biogenesis of PSI and PSII. PMID:24297184

    1. ? -Decay Half-Lives of 110 Neutron-Rich Nuclei across the N =82 Shell Gap: Implications for the Mechanism and Universality of the Astrophysical r Process

      NASA Astrophysics Data System (ADS)

      Lorusso, G.; Nishimura, S.; Xu, Z. Y.; Jungclaus, A.; Shimizu, Y.; Simpson, G. S.; Söderström, P.-A.; Watanabe, H.; Browne, F.; Doornenbal, P.; Gey, G.; Jung, H. S.; Meyer, B.; Sumikama, T.; Taprogge, J.; Vajta, Zs.; Wu, J.; Baba, H.; Benzoni, G.; Chae, K. Y.; Crespi, F. C. L.; Fukuda, N.; Gernhäuser, R.; Inabe, N.; Isobe, T.; Kajino, T.; Kameda, D.; Kim, G. D.; Kim, Y.-K.; Kojouharov, I.; Kondev, F. G.; Kubo, T.; Kurz, N.; Kwon, Y. K.; Lane, G. J.; Li, Z.; Montaner-Pizá, A.; Moschner, K.; Naqvi, F.; Niikura, M.; Nishibata, H.; Odahara, A.; Orlandi, R.; Patel, Z.; Podolyák, Zs.; Sakurai, H.; Schaffner, H.; Schury, P.; Shibagaki, S.; Steiger, K.; Suzuki, H.; Takeda, H.; Wendt, A.; Yagi, A.; Yoshinaga, K.

      2015-05-01

      The ? -decay half-lives of 110 neutron-rich isotopes of the elements from Rb 37 to Sn 50 were measured at the Radioactive Isotope Beam Factory. The 40 new half-lives follow robust systematics and highlight the persistence of shell effects. The new data have direct implications for r -process calculations and reinforce the notion that the second (A ?130 ) and the rare-earth-element (A ?160 ) abundance peaks may result from the freeze-out of an (n ,? )?(? ,n ) equilibrium. In such an equilibrium, the new half-lives are important factors determining the abundance of rare-earth elements, and allow for a more reliable discussion of the r process universality. It is anticipated that universality may not extend to the elements Sn, Sb, I, and Cs, making the detection of these elements in metal-poor stars of the utmost importance to determine the exact conditions of individual r -process events.

    2. Measurement of the Europium Isotope Ratio for the Extremely Metal-Poor, r-Process-Enhanced Star CS31082-001

      E-print Network

      W. Aoki; S. Honda; T. C. Beers; C. Sneden

      2002-11-28

      We report the first measurement of the isotope fraction of europium (151Eu and 153Eu) for the extremely metal-poor, r-process-enhanced star CS31082-001, based on high-resolution spectra obtained with the Subaru Telescope High Dispersion Spectrograph. We have also obtained new measurements of this ratio for two similar stars with previous europium isotope measurements, CS22892-052 and HD115444. The measurements were made using observations of the Eu lines in these spectra that are most significantly affected by isotope shifts and hyperfine splitting. The fractions of 151Eu derived for CS31082-001, CS22892-052, and HD115444 are 0.44, 0.51, and 0.46, respectively, with uncertainties of about +/-0.1. CS31082-001, the first star with a meaningful measurement of U outside of the solar system, is known to exhibit peculiar abundance ratios between the actinide and rare-earth elements (e.g., Th/Eu), ratios that are significantly different from those for other stars with large excesses of r-process elements, such as our two comparison objects. Nevertheless, our analysis indicates that the Eu isotope ratio of CS31082-001 agrees, within the errors, with those of other r-process-enhanced objects, and with that of solar-system material.

    3. ACToR Chemical Structure processing using Open Source ChemInformatics Libraries (FutureToxII)

      EPA Science Inventory

      ACToR (Aggregated Computational Toxicology Resource) is a centralized database repository developed by the National Center for Computational Toxicology (NCCT) at the U.S. Environmental Protection Agency (EPA). Free and open source tools were used to compile toxicity data from ove...

    4. The effects of stem I and loop A on the processing of 5 S rRNA from Drosophila melanogaster.

      PubMed

      Levinger, L; Vasisht, V; Greene, V; Arjun, I

      1992-11-25

      The 135-nucleotide Drosophila melanogaster 5 S RNA precursor is processed by removal of 15 nucleotides from its 3' end before incorporation into the large ribosomal subunit. Mature 5 S RNA consists of five helical stem-loops; stem IV and part of V are dispensable, whereas stem III and the 1/118 G-C base pair closest to the processing site at nucleotide 120 are required for processing (Preiser, P., and Levinger, L. (1991) J. Biol. Chem. 266, 7509-7516; Preiser, P., and Levinger, L. (1991) J. Biol. Chem. 266, 23602-23605). We have investigated the effects of stem I and loop A transversions, transitions, selected additions and deletions on 5 S RNA processing. Stem I single substitutions generally prevent processing, whereas compensatory double substitutions restore a range of processing rates. Proximal to the processing site, stem I double substitutions inhibit processing. In the distal portion of stem I and loop A, the processing effect of paired sequence changes varies widely in an irregular pattern. The 7/112 GU pair and nucleotide 13A least tolerate sequence changes; several mutations clustered close to the stem I-loop A boundary stimulate processing. We interpret these results in terms of the RNA helix path and possible RNA-protein contacts. PMID:1429708

    5. Explaining the Ba, Y, Sr, and Eu abundance scatter in metal-poor halo stars: constraints to the r-process

      NASA Astrophysics Data System (ADS)

      Cescutti, G.; Chiappini, C.

      2014-05-01

      Context. Thanks to the heroic observational campaigns carried out in recent years we now have large samples of metal-poor stars for which measurements of detailed abundances exist. In particular, large samples of stars with metallicities -5 < [Fe/H] <-1 and measured abundances of Sr, Ba, Y, and Eu are now available. These data hold important clues on the nature of the contribution of the first stellar generations to the enrichment of our Galaxy. Aims: We aim to explain the scatter in Sr, Ba, Y, and Eu abundance ratio diagrams unveiled by the metal-poor halo stars. Methods: We computed inhomogeneous chemical evolution models for the Galactic halo assuming different scenarios for the r-process site: the electron-capture (EC) supernovae and the magnetorotationally driven (MRD) supernovae scenarios. We also considered models with and without the contribution of fast-rotating massive stars (spinstars) to an early enrichment by the s-process. A detailed comparison with the now large sample of stars with measured abundances of Sr, Ba, Y, Eu, and Fe is provided (both in terms of scatter plots and number distributions for several abundance ratios). Results: The scatter observed in these abundance ratios of the very metal-poor stars (with [Fe/H] <-2.5) can be explained by combining the s-process production in spinstars, and the r-process contribution coming from massive stars. For the r-process we have developed models for both the EC and the MRD scenarios that match the observations. Conclusions: With the present observational and theoretical constraints we cannot distinguish between the EC and the MRD scenarios in the Galactic halo. Independently of the r-process scenarios adopted, the production of elements by an s-process in spinstars is needed to reproduce the spread in abundances of the light neutron capture elements (Sr and Y) over heavy neutron capture elements (Ba and Eu). We provide a way to test our suggestions by means of the distribution of the Ba isotopic ratios in a [Ba/Fe] or [Sr/Ba] vs. [Fe/H] diagram. Appendix A is available in electronic form at http://www.aanda.org

    6. Rlp7p is associated with 60S preribosomes, restricted to the granular component of the nucleolus, and required for pre-rRNA processing

      PubMed Central

      Gadal, Olivier; Strauss, Daniela; Petfalski, Elisabeth; Gleizes, Pierre-Emmanuel; Gas, Nicole; Tollervey, David; Hurt, Ed

      2002-01-01

      Many analyses have examined subnucleolar structures in eukaryotic cells, but the relationship between morphological structures, pre-rRNA processing, and ribosomal particle assembly has remained unclear. Using a visual assay for export of the 60S ribosomal subunit, we isolated a ts-lethal mutation, rix9-1, which causes nucleolar accumulation of an Rpl25p-eGFP reporter construct. The mutation results in a single amino acid substitution (F176S) in Rlp7p, an essential nucleolar protein related to ribosomal protein Rpl7p. The rix9-1 (rlp7-1) mutation blocks the late pre-RNA cleavage at site C2 in ITS2, which separates the precursors to the 5.8S and 25S rRNAs. Consistent with this, synthesis of the mature 5.8S and 25S rRNAs was blocked in the rlp7-1 strain at nonpermissive temperature, whereas 18S rRNA synthesis continued. Moreover, pre-rRNA containing ITS2 accumulates in the nucleolus of rix9-1 cells as revealed by in situ hybridization. Finally, tagged Rlp7p was shown to associate with a pre-60S particle, and fluorescence microscopy and immuno-EM localized Rlp7p to a subregion of the nucleolus, which could be the granular component (GC). All together, these data suggest that pre-rRNA cleavage at site C2 specifically requires Rlp7p and occurs within pre-60S particles located in the GC region of the nucleolus. PMID:12058014

    7. x : N. (r : {N | (((r r) x) x < (r + 1) (r + 1))}) x:N. (r:{N| (((r * r) x) x < (r + 1) * (r + 1))})

      E-print Network

      x : N. (r : {N | (((r r) x) x r + 1) (r + 1))}) x:N. (r:{N| (((r * r) x) x r + 1) * (r + 1))}) | BY (DivNatInduction 4 · THEN Auto) |\\ | r:{N| (((r * r) 0) 0 r + 1) * (r + 1))} | | 1 BY (With 0 (D 0)· THEN Auto') \\ 1. x: N+ 2. r:{N| (((r * r) (x ÷ 4)) x ÷ 4 r + 1) * (r + 1))} r

    8. The role of binaries in the enrichment of the early Galactic halo. I. r-process-enhanced metal-poor stars

      E-print Network

      Hansen, T T; Nordstrøm, B; Beers, T C; Yoon, J; Buchhave, L A

      2015-01-01

      The detailed chemical composition of most metal-poor halo stars has been found to be highly uniform, but a minority of stars exhibit dramatic enhancements in their abundances of heavy neutron-capture elements and/or of carbon. The key question for Galactic chemical evolution models is whether these peculiarities reflect the composition of the natal clouds, or if they are due to later mass transfer of processed material from a binary companion. If the former case applies, the observed excess of certain elements was implanted within selected clouds in the early ISM from a production site at interstellar distances. Our aim is to determine the frequency and orbital properties of binaries among these chemically peculiar stars. This information provides the basis for deciding whether mass transfer from a binary companion is necessary and sufficient to explain their unusual compositions. This paper discusses our study of a sample of 17 moderately (r-I) and highly (r-II) r-process-element enhanced VMP and EMP stars. ...

    9. Half-lives and branchings for {beta}-delayed neutron emission for neutron-rich Co-Cu isotopes in the r-process

      SciTech Connect

      Hosmer, P.; Estrade, A.; Montes, F.; Ouellette, M.; Pellegrini, E.; Schatz, H.; Aprahamian, A.; Arndt, O.; Pfeiffer, B.; Clement, R. R. C.; Mueller, W. F.; Morton, A. C.; Pereira, J.; Santi, P.; Steiner, M.; Stolz, A.; Farouqi, K.; Kratz, K.-L.; Liddick, S. N.; Mantica, P. F.

      2010-08-15

      The {beta} decays of very neutron-rich nuclides in the Co-Zn region were studied experimentally at the National Superconducting Cyclotron Laboratory using the NSCL {beta}-counting station in conjunction with the neutron detector NERO. We measured the branchings for {beta}-delayed neutron emission (P{sub n} values) for {sup 74}Co (18{+-}15%) and {sup 75-77}Ni (10{+-}2.8%, 14{+-}3.6%, and 30{+-}24%, respectively) for the first time, and remeasured the P{sub n} values of {sup 77-79}Cu, {sup 79,81}Zn, and {sup 82}Ga. For {sup 77-79}Cu and for {sup 81}Zn we obtain significantly larger P{sub n} values compared to previous work. While the new half-lives for the Ni isotopes from this experiment had been reported before, we present here in addition the first half-life measurements of {sup 75}Co (30{+-}11 ms) and {sup 80}Cu (170{sub -50}{sup +110} ms). Our results are compared with theoretical predictions, and their impact on various types of models for the astrophysical rapid neutron-capture process (r-process) is explored. We find that with our new data, the classical r-process model is better able to reproduce the A=78-80 abundance pattern inferred from the solar abundances. The new data also influence r-process models based on the neutrino-driven high-entropy winds in core collapse supernovae.

    10. Compact Ku-Band T/R Module for High-Resolution Radar Imaging of Cold Land Processes

      NASA Technical Reports Server (NTRS)

      Andricos, Constantine; Yueh, Simon H.; Krimskiy, Vladimir A.; Rahmat-Samii, Yahya

      2010-01-01

      Global measurement of terrestrial snow cover is critical to two of the NASA Earth Science focus areas: (1) climate variability and change and (2) water and energy cycle. For radar backscatter measurements, Ku-band frequencies, scattered mainly within the volume of the snowpack, are most suitable for the SWE (snow-water equivalent) measurements. To isolate the complex effects of different snowpack (density and snowgrain size), and underlying soil properties and to distinctly determine SWE, the space-based synthetic aperture radar (SAR) system will require a dual-frequency (13.4 and 17.2 GHz) and dual polarization approach. A transmit/receive (T/R) module was developed operating at Ku-band frequencies to enable the use of active electronic scanning phased-array antenna for wide-swath, high-resolution SAR imaging of terrestrial snow cover. The T/R module has an integrated calibrator, which compensates for all environmental- and time-related changes, and results in very stable power and amplitude characteristics. The module was designed to operate over the full frequency range of 13 to 18 GHz, although only the two frequencies, 13.4 GHz and 17.2 GHz, will be used in this SAR radar application. Each channel of the transmit module produces > 4 W (35 dbm) over the operating bandwidth of 20 MHz. The stability requirements of <0.1 dB receive gain accuracy and <0.1 dB transmit power accuracy over a wide temperature range are achieved using a self-correction scheme, which does real-time amplitude calibration so that the module characteristics are continually corrected. All the calibration circuits are within the T/R module. The timing and calibration sequence is stored in a control FPGA (field-programmable gate array) while an internal 128K 8bit high-speed RAM (random access memory) stores all the calibration values. The module was designed using advanced components and packaging techniques to achieve integration of the electronics in a 2 x6.5x1-in. (5x17x2.5-cm) package. The module size allows 4 T/R modules to feed the 16 16-element subarray on an antenna panel. The T/R module contains four transmit channels and eight receive channels (horizontal and vertical polarizations).

    11. TRIBUTE TO FOUNDERS: R. BYRON BIRD. SOFT MATTER: SYNTHESIS, PROCESSING AND PRODUCTS Foam Electrospinning: A Multiple Jet, Needle-less Process

      E-print Network

      Khan, Saad A.

      Electrospinning: A Multiple Jet, Needle-less Process for Nanofiber Production Alina K. Higham, Christina Tang electrospinning short- comings such as needle clogging and restrictions in production rate is presented. Using, suggesting charge distribution through the bulk foam facilitates electrospinning. Similar trends between foam

    12. MEMBRANE-MODERATED STRIPPING PROCESS FOR REMOVING VOCS FROM WATER IN A COMPOSITE HOLLOW FIBER MODULE. (R825511C027)

      EPA Science Inventory

      The "stripmeation" process for removing volatile organic compounds (VOCs) from water has been introduced and studied. An aqueous solution of the VOC is passed through the bores of hydrophobic microporous polypropylene hollow fibers having a plasma polymerized silicone ...

    13. Processing and analysis of commercial satellite image data of the nuclear accident near Chernobyl, U. S. S. R

      SciTech Connect

      Sadowski, F.G.; Covington, S.J.

      1987-01-01

      Advanced digital processing techniques were applied to Landsat-5 Thematic Mapper (TM) data and SPOT high-resolution visible (HRV) panchromatic data to maximize the utility of images of a nuclear power plant emergency at Chernobyl in the Soviet Ukraine. The results of the data processing and analysis illustrate the spectral and spatial capabilities of the two sensor systems and provide information about the severity and duration of the events occurring at the power plant site.

    14. NOL11, implicated in the pathogenesis of North American Indian childhood cirrhosis, is required for pre-rRNA transcription and processing.

      PubMed

      Freed, Emily F; Prieto, José-Luis; McCann, Kathleen L; McStay, Brian; Baserga, Susan J

      2012-01-01

      The fundamental process of ribosome biogenesis requires hundreds of factors and takes place in the nucleolus. This process has been most thoroughly characterized in baker's yeast and is generally well conserved from yeast to humans. However, some of the required proteins in yeast are not found in humans, raising the possibility that they have been replaced by functional analogs. Our objective was to identify non-conserved interaction partners for the human ribosome biogenesis factor, hUTP4/Cirhin, since the R565W mutation in the C-terminus of hUTP4/Cirhin was reported to cause North American Indian childhood cirrhosis (NAIC). By screening a yeast two-hybrid cDNA library derived from human liver, and through affinity purification followed by mass spectrometry, we identified an uncharacterized nucleolar protein, NOL11, as an interaction partner for hUTP4/Cirhin. Bioinformatic analysis revealed that NOL11 is conserved throughout metazoans and their immediate ancestors but is not found in any other phylogenetic groups. Co-immunoprecipitation experiments show that NOL11 is a component of the human ribosomal small subunit (SSU) processome. siRNA knockdown of NOL11 revealed that it is involved in the cleavage steps required to generate the mature 18S rRNA and is required for optimal rDNA transcription. Furthermore, abnormal nucleolar morphology results from the absence of NOL11. Finally, yeast two-hybrid analysis shows that NOL11 interacts with the C-terminus of hUTP4/Cirhin and that the R565W mutation partially disrupts this interaction. We have therefore identified NOL11 as a novel protein required for the early stages of ribosome biogenesis in humans. Our results further implicate a role for NOL11 in the pathogenesis of NAIC. PMID:22916032

    15. Novel Magnetically Fluidized Bed Reactor Development for the Looping Process: Coal to Hydrogen Production R&D

      SciTech Connect

      Mei, Renwei; Hahn, David; Klausner, James; Petrasch, Jorg; Mehdizadeh, Ayyoub; Allen, Kyle; Rahmatian, Nima; Stehle, Richard; Bobek, Mike; Al-Raqom, Fotouh; Greek, Ben; Li, Like; Chen, Chen; Singh, Abhishek; Takagi, Midori; Barde, Amey; Nili, Saman

      2013-09-30

      The coal to hydrogen project utilizes the iron/iron oxide looping process to produce high purity hydrogen. The input energy for the process is provided by syngas coming from gasification process of coal. The reaction pathways for this process have been studied and favorable conditions for energy efficient operation have been identified. The Magnetically Stabilized Porous Structure (MSPS) is invented. It is fabricated from iron and silica particles and its repeatable high performance has been demonstrated through many experiments under various conditions in thermogravimetric analyzer, a lab-scale reactor, and a large scale reactor. The chemical reaction kinetics for both oxidation and reduction steps has been investigated thoroughly inside MSPS as well as on the surface of very smooth iron rod. Hydrogen, CO, and syngas have been tested individually as the reducing agent in reduction step and their performance is compared. Syngas is found to be the most pragmatic reducing agent for the two-step water splitting process. The transport properties of MSPS including porosity, permeability, and effective thermal conductivity are determined based on high resolution 3D CT x-ray images obtained at Argonne National Laboratory and pore-level simulations using a lattice Boltzmann Equation (LBE)-based mesoscopic model developed during this investigation. The results of those measurements and simulations provide necessary inputs to the development of a reliable volume-averaging-based continuum model that is used to simulate the dynamics of the redox process in MSPS. Extensive efforts have been devoted to simulate the redox process in MSPS by developing a continuum model consist of various modules for conductive and radiative heat transfer, fluid flow, species transport, and reaction kinetics. Both the Lagrangian and Eulerian approaches for species transport of chemically reacting flow in porous media have been investigated and verified numerically. Both approaches lead to correct prediction of hydrogen production rates over a large range of experimental conditions in the laboratory scale reactor and the bench-scale reactor. In the economic analysis, a comparison of the hydrogen production plants using iron/iron oxide looping cycle and the conventional process has been presented. Plant configurations are developed for the iron/iron oxide looping cycle. The study suggests a higher electric power generation but a lower hydrogen production efficiency comparing with the conventional process. Additionally, it was shown that the price of H{sub 2} obtained from our reactor can be as low as $1.7/kg, which is 22% lower than the current price of the H{sub 2} obtained from reforming plants.

    16. Ferromanganese nodules from MANOP Sites H, S, and R-Control of mineralogical and chemical composition by multiple accretionary processes

      USGS Publications Warehouse

      Dymond, J.; Lyle, M.; Finney, B.; Piper, D.Z.; Murphy, K.; Conard, R.; Pisias, N.

      1984-01-01

      The chemical composition of ferromanganese nodules from the three nodule-bearing MANOP sites in the Pacific can be accounted for in a qualitative way by variable contributions of distinct accretionary processes. These accretionary modes are: 1. (1) hydrogenous, i.e., direct precipitation or accumulation of colloidal metal oxides in seawater, 2. (2) oxic diagenesis which refers to a variety of ferromanganese accretion processes occurring in oxic sediments; and 3. (3) suboxic diagenesis which results from reduction of Mn+4 by oxidation of organic matter in the sediments. Geochemical evidence suggests processes (1) and (2) occur at all three MANOP nodule-bearing sites, and process (3) occurs only at the hemipelagic site, H, which underlies the relatively productive waters of the eastern tropical Pacific. A normative model quantitatively accounts for the variability observed in nearly all elements. Zn and Na, however, are not well explained by the three end-member model, and we suggest that an additional accretionary process results in greater variability in the abundances of these elements. Variable contributions from the three accretionary processes result in distinct top-bottom compositional differences at the three sites. Nodule tops from H are enriched in Ni, Cu, and Zn, instead of the more typical enrichments of these elements in nodule bottoms. In addition, elemental correlations typical of most pelagic nodules are reversed at site H. The three accretionary processes result in distinct mineralogies. Hydrogenous precipitation produces ??MnO2. Oxic diagenesis, however, produces Cu-Ni-rich todorokite, and suboxic diagenesis results in an unstable todorokite which transforms to a 7 A?? phase ("birnessite") upon dehydration. The presence of Cu and Ni as charge-balancing cations influence the stability of the todorokite structure. In the bottoms of H nodules, which accrete dominantly by suboxic diagenesis, Na+ and possibly Mn+2 provide much of the charge balance for the todorokite structure. Limited growth rate data for H nodules suggest suboxic accretion is the fastest of the three processes, with rates at least 200 mm/106 yr. Oxic accretion is probably 10 times slower and hydrogenous 100 times slower. Since these rates predict more suboxic component in bulk nodules than is calculated by the normative analysis, we propose that suboxic accretion is a non-steady-state process. Variations in surface water productivity cause pulses of particulate flux to the sea floor which result in transient Mn reduction in the surface sediments and reprecipitation on nodule surfaces. ?? 1984.

    17. Comprehensive analysis of gluten in processed foods using a new extraction method and a competitive ELISA based on the R5 antibody.

      PubMed

      Mena, María C; Lombardía, Manuel; Hernando, Alberto; Méndez, Enrique; Albar, Juan P

      2012-03-15

      The only treatment for coeliac disease is to follow a strict, life-long gluten-free diet. It is therefore essential to use a highly sensitive, specific technique for gluten analysis in foods. Nowadays, the usual method for determining gluten content in gluten-free foods, internationally accepted by the Codex Alimentarius Commission, is the R5 antibody-based sandwich ELISA, combined with the cocktail-extraction solution. This technique requires at least two epitopes in the protein, but in hydrolysed foods, proteins are fragmented during food processing and converted into peptides in which only one toxic epitope may appear. Consequently, it was necessary to develop a new competitive immunoassay that, together with a reliable, compatible extraction solution, would provide a complete gluten analysis in any kind of food. We analysed commercial foods and home-made maize breads spiked with a known amount of gliadins using the sandwich R5 ELISA and the new competitive R5 ELISA that has been developed. These foods had previously been extracted with 60% ethanol/water, the cocktail solution or the new extracting solution called UPEX (universal prolamin and glutelin extractant solution). The complementary SDS-PAGE and western blot techniques were also used to confirm the gluten content. The limits of detection and quantification of the competitive R5 ELISA were 0.36 and 1.22 ng/ml of gliadins, respectively. The intra- and inter-assay precisions based on two samples were, respectively, 7.3% and 5.4% for the first sample and 9.9% and 6.3% for the second. This new assay was a better technique than the sandwich R5 ELISA for detecting gliadins quantitatively in hydrolysed foods. Regarding the extraction procedure, we did not find any significant interference from components of the UPEX solution at the concentration used. In addition, the UPEX solution extraction was compatible with the R5 western blot and mass spectrometry techniques. The competitive R5 ELISA we developed, combined with the UPEX solution described here, is a very useful tool for detecting and quantifying gluten in any kind of food samples, including heat-treated and/or hydrolysed ones. PMID:22365676

    18. r.avaflow: An advanced open source computational framework for the GIS-based simulation of two-phase mass flows and process chains

      NASA Astrophysics Data System (ADS)

      Mergili, Martin; Fischer, Jan-Thomas; Fellin, Wolfgang; Ostermann, Alexander; Pudasaini, Shiva P.

      2015-04-01

      Geophysical mass flows stand for a broad range of processes and process chains such as flows and avalanches of snow, soil, debris or rock, and their interactions with water bodies resulting in flood waves. Despite considerable efforts put in model development, the simulation, and therefore the appropriate prediction of these types of events still remains a major challenge in terms of the complex material behaviour, strong phase interactions, process transformations and the complex mountain topography. Sophisticated theories exist, but they have hardly been brought to practice yet. We fill this gap by developing a novel and unified high-resolution computational tool, r.avaflow, representing a comprehensive and advanced open source GIS simulation environment for geophysical mass flows. Based on the latest and most advanced two-phase physical-mathematical models, r.avaflow includes the following features: (i) it is suitable for a broad spectrum of mass flows such as rock, rock-ice and snow avalanches, glacial lake outburst floods, debris and hyperconcentrated flows, and even landslide-induced tsunamis and submarine landslides, as well as process chains involving more than one of these phenomena; (ii) it accounts for the real two-phase nature of many flow types: viscous fluids and solid particles are considered separately with advanced mechanics and strong phase interactions; (iii) it is freely available and adoptable along with the GRASS GIS software. In the future, it will include the intrinsic topographic influences on the flow dynamics and morphology as well as an advanced approach to simulate the entrainment and deposition of solid and fluid material. As input r.avaflow needs information on (a) the mountain topography, (b) the material properties and (c) the spatial distribution of the solid and fluid release masses or one or more hydrographs of fluid and solid material. We demonstrate the functionalities and performance of r.avaflow by using some generic and real-world examples including a channelized debris flow with hydrograph input, and a rock avalanche impacting a reservoir, triggering a flood wave overtopping and eroding the dam. Project web site: http://www.avaflow.org/

    19. Beta-decay half-lives and beta-delayed neutron emission probabilities of nuclei in the region below A=110, relevant for the r-process

      E-print Network

      J. Pereira; S. Hennrich; A. Aprahamian; O. Arndt; A. Becerril; T. Elliot; A. Estrade; D. Galaviz; R. Kessler; K. -L. Kratz; G. Lorusso; P. F. Mantica; M. Matos; P. Moller; F. Montes; B. Pfeiffer; H. Schatz; F. Schertz; L. Schnorrenberger; E. Smith; A. Stolz; M. Quinn; W. B. Walters; A. Wohr

      2009-02-10

      Measurements of the beta-decay properties of r-process nuclei below A=110 have been completed at the National Superconducting Cyclotron Laboratory, at Michigan State University. Beta-decay half-lives for Y-105, Zr-106,107 and Mo-111, along with beta-delayed neutron emission probabilities of Y-104, Mo-109,110 and upper limits for Y-105, Zr-103,104,105,106,107 and Mo-108,111 have been measured for the first time. Studies on the basis of the quasi-random phase approximation are used to analyze the ground-state deformation of these nuclei.

    20. Beta-decay half-lives and beta-delayed neutron emisison probabilities of nuclei in the region A. 110, relevant for the r-process

      SciTech Connect

      Moller, Peter; Pereira, J; Hennrich, S; Aprahamian, A; Arndt, O; Becerril, A; Elliot, T; Estrade, A; Galaviz, D; Kessler, R; Kratz, K - L; Lorusso, G; Mantica, P F; Matos, M; Montes, F; Pfeiffer, B; Schatz, F; Schnorrenberger, L; Smith, E; Stolz, A; Quinn, M; Walters, W B; Wohr, A

      2009-01-01

      Measurements of the {beta}-decay properties of A {approx}< 110 r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory, at Michigan State University. {beta}-decay half-lives for {sup 105}Y, {sup 106,107}Zr and {sup 108,111}Mo, along with ,B-delayed neutron emission probabilities of 104Y, 109,11OMo and upper limits for 105Y, 103-107Zr and 108,111 Mo have been measured for the first time. Studies on the basis of the quasi-random phase approximation are used to analyze the ground-state deformation of these nuclei.

    1. {beta}-decay half-lives and {beta}-delayed neutron emission probabilities of nuclei in the region A < or approx. 110, relevant for the r process

      SciTech Connect

      Pereira, J.; Galaviz, D.; Matos, M.; Montes, F.; Hennrich, S.; Kessler, R.; Schertz, F.; Aprahamian, A.; Quinn, M.; Woehr, A.; Arndt, O.; Pfeiffer, B.; Becerril, A.; Elliot, T.; Estrade, A.; Lorusso, G.; Schatz, H.; Kratz, K.-L.; Mantica, P. F.; Moeller, P.

      2009-03-15

      Measurements of {beta}-decay properties of A < or approx. 110 r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory at Michigan State University. {beta}-decay half-lives for {sup 105}Y, {sup 106,107}Zr, and {sup 111}Mo, along with {beta}-delayed neutron emission probabilities of {sup 104}Y, {sup 109,110}Mo and upper limits for {sup 105}Y, {sup 103-107}Zr, and {sup 108,111}Mo have been measured for the first time. Studies on the basis of the quasi-random-phase approximation are used to analyze the ground-state deformation of these nuclei.

    2. INVESTIGATION OF AQUEOUS BIPHASIC SYSTEMS FOR THE SEPARATIONS OF LIGNINS FROM CELLULOSE IN THE PAPER PULPING PROCESS. (R826732)

      EPA Science Inventory

      In efforts to apply a polymer-based aqueous biphasic system (ABS) extraction to the paper pulping process, the study of the distribution of various lignin and cellulosic fractions in ABS and the effects of temperature on system composition and solute partitioning have been inv...

    3. Diversity in the Software Development Process Victoria Hilford, Michael R. Lyu \\Lambda , Bojan Cukic, Anouar Jamoussi, Farokh B. Bastani

      E-print Network

      Lyu, Michael R.

      with respect to design faults. \\Lambda Bell Labs., Lucent Technologies, Room 2A­413 600 Mountain Av­ enue, TX 77204 ­ 3475 Email: FBastani@uh.edu Abstract Various methods have been proposed for building fault survived the development process. The two best­known methods of building fault­tolerant soft­ ware are n

    4. A KINETIC MODEL FOR H2O2/UV PROCESS IN A COMPLETELY MIXED BATCH REACTOR. (R825370C076)

      EPA Science Inventory

      A dynamic kinetic model for the advanced oxidation process (AOP) using hydrogen peroxide and ultraviolet irradiation (H2O2/UV) in a completely mixed batch reactor (CMBR) is developed. The model includes the known elementary chemical and photochemical reac...

    5. Chemogenomic Study of Carboplatin in Saccharomyces cerevisiae: Inhibition of the NEDDylation Process Overcomes Cellular Resistance Mediated by HuR and Cullin Proteins

      PubMed Central

      Custodio, Débora Fernandes; Freitas, Vanessa Morais; Monteiro, Gisele

      2015-01-01

      The use of carboplatin in cancer chemotherapy is limited by the emergence of drug resistance. To understand the molecular basis for this resistance, a chemogenomic screen was performed in 53 yeast mutants that had previously presented strong sensitivity to this widely used anticancer agent. Thirty-four mutants were responsive to carboplatin, and from these, 21 genes were selected for further studies because they have human homologues. Sixty percent of these yeast genes possessed human homologues which encoded proteins that interact with cullin scaffolds of ubiquitin ligases, or whose mRNA are under the regulation of Human antigen R (HuR) protein. Both HuR and cullin proteins are regulated through NEDDylation post-translational modification, and so our results indicate that inhibition of this process should sensitise resistant tumour cells to carboplatin. We showed that treatment of a tumour cell line with MLN4924, a NEDDylation inhibitor, overcame the resistance to carboplatin. Our data suggest that inhibition of NEDDylation may be a useful strategy to resensitise tumour cells in patients that have acquired carboplatin resistance. PMID:26692264

    6. Neutron-Capture Elements in the Double-Enhanced Star HE 1305-0007: a New s- and r-Process Paradigm

      E-print Network

      Wen-Yuan Cui; D. N. Cui; Y. S. Du; B. Zhang

      2007-04-04

      The star HE 1305-0007 is a metal-poor double-enhanced star with metallicity [Fe/H] $=-2.0$, which is just at the upper limit of the metallicity for the observed double-enhanced stars. Using a parametric model, we find that almost all s-elements were made in a single neutron exposure. This star should be a member of a post-common-envelope binary. After the s-process material has experienced only one neutron exposure in the nucleosynthesis region and is dredged-up to its envelope, the AGB evolution is terminated by the onset of common-envelope evolution. Based on the high radial-velocity of HE 1305-0007, we speculate that the star could be a runaway star from a binary system, in which the AIC event has occurred and produced the r-process elements.

    7. High-resolution microscopy of active ribosomal genes and key members of the rRNA processing machinery inside nucleolus-like bodies of fully-grown mouse oocytes.

      PubMed

      Shishova, Kseniya V; Khodarovich, Yuriy M; Lavrentyeva, Elena A; Zatsepina, Olga V

      2015-10-01

      Nucleolus-like bodies (NLBs) of fully-grown (germinal vesicle, GV) mammalian oocytes are traditionally considered as morphologically distinct entities, which, unlike normal nucleoli, contain transcribed ribosomal genes (rDNA) solely at their surface. In the current study, we for the first time showed that active ribosomal genes are present not only on the surface but also inside NLBs of the NSN-type oocytes. The "internal" rRNA synthesis was evidenced by cytoplasmic microinjections of BrUTP as precursor and by fluorescence in situ hybridization with a probe to the short-lived 5'ETS segment of the 47S pre-rRNA. We further showed that in the NLB mass of NSN-oocytes, distribution of active rDNA, RNA polymerase I (UBF) and rRNA processing (fibrillarin) protein factors, U3 snoRNA, pre-rRNAs and 18S/28S rRNAs is remarkably similar to that in somatic nucleoli capable to make pre-ribosomes. Overall, these observations support the occurrence of rDNA transcription, rRNA processing and pre-ribosome assembly in the NSN-type NLBs and so that their functional similarity to normal nucleoli. Unlike the NSN-type NLBs, the NLBs of more mature SN-oocytes do not contain transcribed rRNA genes, U3 snoRNA, pre-rRNAs, 18S and 28S rRNAs. These results favor the idea that in a process of transformation of NSN-oocytes to SN-oocytes, NLBs cease to produce pre-ribosomes and, moreover, lose their rRNAs. We also concluded that a denaturing fixative 70% ethanol used in the study to fix oocytes could be more appropriate for light microscopy analysis of nucleolar RNAs and proteins in mammalian fully-grown oocytes than a commonly used cross-linking aldehyde fixative, formalin. PMID:26226217

    8. The role of binaries in the enrichment of the early Galactic halo. I. r-process-enhanced metal-poor stars

      NASA Astrophysics Data System (ADS)

      Hansen, T. T.; Andersen, J.; Nordström, B.; Beers, T. C.; Yoon, J.; Buchhave, L. A.

      2015-11-01

      Context. The detailed chemical composition of most metal-poor halo stars has been found to be highly uniform, but a minority of stars exhibit dramatic enhancements in their abundances of heavy neutron-capture elements and/or of carbon. The key question for Galactic chemical evolution models is whether these peculiarities reflect the composition of the natal clouds, or if they are due to later (post-birth) mass transfer of chemically processed material from a binary companion. If the former case applies, the observed excess of certain elements was implanted within selected clouds in the early ISM from a production site at interstellar distances. Aims: Our aim is to determine the frequency and orbital properties of binaries among these chemically peculiar stars. This information provides the basis for deciding whether local mass transfer from a binary companion is necessary and sufficient to explain their unusual compositions. This paper discusses our study of a sample of 17 moderately (r-I) and highly (r-II) r-process-element enhanced VMP and EMP stars. Methods: High-resolution, low signal-to-noise spectra of the stars were obtained at roughly monthly intervals over eight years with the FIES spectrograph at the Nordic Optical Telescope. From these spectra, radial velocities with an accuracy of ~100 m s-1 were determined by cross-correlation against an optimized template. Results: Fourteen of the programme stars exhibit no significant radial-velocity variation over this temporal window, while three are binaries with orbits of typical eccentricity for their periods, resulting in a normal binary frequency of ~18 ± 6% for the sample. Conclusions: Our results confirm our preliminary conclusion from 2011, based on partial data, that the chemical peculiarity of the r-I and r-II stars is not caused by any putative binary companions. Instead, it was imprinted on the natal molecular clouds of these stars by an external, distant source. Models of the ISM in early galaxies should account for such mechanisms. Appendices are available in electronic form at http://www.aanda.org

    9. {gamma}{gamma}{r_arrow}{ital Ze}{sup +}{ital e{minus}} and related processes using polarized photon beams

      SciTech Connect

      Ginzburg, I.F.; Serbo, V.G.

      1994-03-01

      The cross sections for processes with the production of {ital Z} and pairs of leptons or quarks in the {gamma}{gamma} collisions are calculated. They are large enough to give an important background for Higgs boson hunting at future photon colliders if the Higgs boson mass is about 100 GeV and they are small for the production of two {ital Z}`s. The equivalent electron approximation for the polarized photon beams is presented.

    10. Process innovation in high-performance systems: From polymeric composites R&D to design and build of airplane showers

      NASA Astrophysics Data System (ADS)

      Wu, Yi-Jui

      In the aerospace industry reducing aircraft weight is key because it increases flight performance and drives down operating costs. With fierce competition in the commercial aircraft industry, companies that focused primarily on exterior aircraft performance design issues are turning more attention to the design of aircraft interior. Simultaneously, there has been an increase in the number of new amenities offered to passengers especially in first class travel and executive jets. These new amenities present novel and challenging design parameters that include integration into existing aircraft systems without sacrificing flight performance. The objective of this study was to design a re-circulating shower system for an aircraft that weighs significantly less than pre-existing shower designs. This was accomplished by integrating processes from polymeric composite materials, water filtration, and project management. Carbon/epoxy laminates exposed to hygrothermal cycling conditions were evaluated and compared to model calculations. Novel materials and a variety of fabrication processes were developed to create new types of paper for honeycomb applications. Experiments were then performed on the properties and honeycomb processability of these new papers. Standard water quality tests were performed on samples taken from the re-circulating system to see if current regulatory standards were being met. These studies were executed and integrated with tools from project management to design a better shower system for commercial aircraft applications.

    11. Experimental study of the {sup 11,12}B(n,gamma) reactions and their influence on r-process nucleosynthesis of light elements.

      SciTech Connect

      Lee, H. Y.; Greene, J. P.; Jiang, C. L.; Pardo, R. C.; Rehm , K. E.; Schiffer, J. P.; Wuosmaa, A. H.; Goodman, N. J.; Lighthall, J. C.; Marley, S. T.; Otsuki, K.; Patel, N.; Beard, M.; Notani, M.; Tang, X. D.; Physics; Western Michigan Univ.; GSI; Colorado School of Mines; Univ. of Notre Dame

      2010-01-01

      We have studied the neutron-transfer reactions {sup 11,12}B(d,p){sup 12,13}B in inverse kinematics to obtain information about the neutron-capture reactions {sup 11,12}B(n,{gamma}). These capture reactions are suggested to play a role in seeding r-process nucleosynthesis through the production of light, neutron-rich nuclei. The neutron spectroscopic factors of the states in {sup 12,13}B were deduced and the branching ratio of the neutron-unbound state at E{sub X} = 3.389 MeV in {sup 12}B was obtained to provide the ratio of partial widths, {Lambda}{sub n}/{Lambda}{sub {gamma}}. The reaction rates for {sup 11,12}B(n,{gamma}) are estimated for direct captures and resonant captures and compared with previous compilations. The astrophysical implications, especially for neutrino-driven wind models in core-collapse supernovae, are discussed in the r-process network framework using our updated reaction rates.

    12. Co-production of light p-, s- and r-process isotopes in the high-entropy wind of type II supernovae

      E-print Network

      Farouqi, K; Pfeiffer, B

      2009-01-01

      We have performed large-scale nucleosynthesis calculations within the high-entropy-wind (HEW) scenario of type II supernovae. The primary aim was to constrain the conditions for the production of the classical "p-only" isotopes of the light trans-Fe elements. We find, however, that for electron fractions in the range 0.458 $\\le$ Y$_e$ $\\le$ 0.478, sizeable abundances of p-, s- and r-process nuclei between $^{64}$Zn and $^{98}$Ru are coproduced in the HEW at low entropies (S $\\le$ 100) by a primary charged-particle process after an $\\alpha$-rich freezeout. With the above Y$_e$ -- S correlation, most of the predicted isotopic abundance ratios within a given element (e.g. $^{64}$Zn(p)/$^{70}$Zn(r) or $^{92}$Mo(p)/$^{94}$Mo(p)), as well as of neighboring elements (e.g. $^{70}$Ge(s+p)/$^{74}$Se(p) or $^{74}$Se(p)/$^{78}$Kr(p)) agree with the observed Solar-System ratios. Taking the Mo isotopic chain as a particularly challenging example, we show that our HEW model can account for the production of all 7 stable iso...

    13. {beta}-Decay Half-Lives of Very Neutron-Rich Kr to Tc Isotopes on the Boundary of the r-Process Path: An Indication of Fast r-Matter Flow

      SciTech Connect

      Nishimura, S.; Li, Z.; Watanabe, H.; Kurata-Nishimura, M.; Baba, H.; Doornenbal, P.; Isobe, T.; Sakurai, H.; Scheit, H.; Steppenbeck, D.; Yoshinaga, K.; Sumikama, T.; Miyashita, Y.; Chiba, J.; Nakano, T.; Sugimoto, K.; Takano, S.; Tachibana, T.; Yamaguchi, K.; Odahara, A.

      2011-02-04

      The {beta}-decay half-lives of 38 neutron-rich isotopes from {sub 36}Kr to {sub 43}Tc have been measured; the half-lives of {sup 100}Kr, {sup 103-105}Sr, {sup 106-108}Y, {sup 108-110}Zr, {sup 111,112}Nb, {sup 112-115}Mo, and {sup 116,117}Tc are reported here. The results when compared with previous standard models indicate an overestimation in the predicted half-lives by a factor of 2 or more in the A{approx_equal}110 region. A revised model based on the second generation gross theory of {beta} decay better predicts the measured half-lives and suggests a more rapid flow of the rapid neutron-capture process (r-matter flow) through this region than previously predicted.

    14. Shelf Edge Exchange Processes, II: SEEP2-08, R/V ENDEAVOR cruise 188. Hydrographic data report

      SciTech Connect

      Wilson, C.; Behrens, W.J.; Flagg, C.N.; Wallace, D.W.R.; Wilke, R.J.; Wyman, K.D.

      1989-12-01

      The Shelf Edge Exchange Processes (SEEP) program sponsored by the United States Department of Energy is a multi-institutional effort designed to investigate the flux of suspended material from the continental shelf to the waters of the upper slope, and then possibly into the slope sediments. Phase I of SEEP consisted of a series of nine cruises and a mooring array across the outer continental shelf of New England during 1983--1984 (Behrens and Flagg, 1986). Phase II focused specifically on the shelf/slope frontal region of the mid-Atlantic bight off the Delmarva Peninsula. This project consisted of a series of ten cruises, a mooring array, and a series of over-flights by NASA aircraft. Hydrographic data were collected on eight of the cruises, six of which were primarily mooring deployment or recovery cruises. The cruises were consecutively designated SEEP2-01 to SEEP2-10. Two cruises (SEEP2-04 and SEEP2-07) were dedicated to investigating benthic processes and hydrographic data were not collected.

    15. Modelling pre-rRNA 

      E-print Network

      Axt, Konstantin

      2013-06-29

      In this project rRNA maturation was investigated with the help of mathematical models of processing pathways from pre-rRNA to mature rRNA species. Previously described models were transferred from Excel to Mathematica. ...

    16. Development and evaluation of wastewater-treatment processes at the H-Coal site in Catlettsburg, Kentucky. Volume I. Design summary and R and D task identification

      SciTech Connect

      Oswald, G.E.; Walker, J.F.; Brown, C.H.; Klein, J.A.; Genung, R.K.

      1982-04-01

      The design of a mobile process development unit (PDU) for coal conversion wastewater treatment and an overview of the associated R and D program for its use are described. The PDU consists of three modular units, which can be arranged in various sequences: carbon adsorption, ozonation, and reverse osmosis. Each of the units has a nominal flow capacity of approx. 60 mL of wastewater feed per second (1 gpm). The feed to the PDU will be taken as a sidestream from the existing wastewater treatment system at the H-Coal site. It will have been processed through oil-water separation and distillation stripping, and can be taken both before and after bio-oxidation by an activated sludge process. The ozonation system experimental parameters are ozone contact time, ozone treatment rate, column pressure, and pH. The system will be analyzed as a continuous stirred tank reactor. The calculated results will include ozone reaction, treatment, and absorption rates, contaminant depletion and reaction rates, ozone absorption and contaminant removal efficiencies, and ozone volumetric mass-transfer coefficients. The carbon adsorption system will be operated to obtain bed-depth-service-time (BDST) data for various carbons and operating conditions. The BDST method will yield the rate of carbon exhaustion as well as the minimum depth of carbon required to remove contaminants. Reverse osmosis will be studied to measure dissolved solids rejection efficiency, permeate recovery, and fouling characteristics of various commercially available membranes.

    17. The origin and evolution of r- and s-process elements in the Milky Way stellar disk

      E-print Network

      Battistini, Chiara

      2015-01-01

      Knowledge of abundance ratios as functions of metallicity can lead to insights on the origin and evolution of our Galaxy and its stellar populations. We aim to trace the chemical evolution of the neutron-capture elements Sr, Zr, La, Ce, Nd, Sm, and Eu in the Milky Way stellar disk to constrain the formation sites of these elements as well as to probe the evolution of the Galactic thin and thick disks. Using spectra of high resolution and high signal-to-noise we determine Sr, Zr, La, Ce, Nd, Sm, and Eu abundances for a sample of 593 F and G dwarf stars in the Solar neighbourhood. We present abundance results for Sr, Zr, La, Ce, Nd, Sm and Eu. We find that Nd, Sm, and Eu show trends similar to what is observed for the alpha-elements when compared to [Fe/H]. [Sr/Fe] and [Zr/Fe] show decreasing abundance ratios for increasing metallicity, reaching sub-solar values at super-solar metallicities. [La/Fe] and [Ce/Fe] do not show any clear trend with metallicity. The rapid neutron-capture process is active early in th...

    18. Optimization of process parameters for the electrical properties in Ga-doped ZnO thin films prepared by r.f. magnetron sputtering

      NASA Astrophysics Data System (ADS)

      Zhu, D. L.; Wang, Q.; Han, S.; Cao, P. J.; Liu, W. J.; Jia, F.; Zeng, Y. X.; Ma, X. C.; Lu, Y. M.

      2014-04-01

      Ga-doped ZnO (GZO) transparent conductive thin films have been deposited on quartz substrates by r.f. magnetron sputtering. The optimization of four process parameters (i.e., vacuum annealing temperature, r.f. power, sputtering pressure, and Ar flow rate) based on Taguchi method has been systematically studied in order to obtain the minimum resistivity. Compared to the optimal parameter set selected from orthogonal array by Taguchi method, the optimal prediction design can receive an improvement of 22.3% in electrical resistivity, and the corresponding resistivity is 8.08 × 10-4 ? cm. The analysis of variance shows that vacuum annealing temperature is the most significant influencing parameter on the electrical properties in GZO films. X-ray photoelectron spectroscopy and photoluminescence results exhibit that the enhancement in electrical conductivity after vacuum annealing is ascribed to the variation of the chemical states of oxygen in GZO films. With the increase in annealing temperature, the content of absorbed oxygen and interstitial oxygen as acceptors will decrease.

    19. Genome-wide analysis of small nucleolar RNAs of Leishmania major reveals a rich repertoire of RNAs involved in modification and processing of rRNA.

      PubMed

      Eliaz, Dror; Doniger, Tirza; Tkacz, Itai Dov; Biswas, Viplov Kumar; Gupta, Sachin Kumar; Kolev, Nikolay G; Unger, Ron; Ullu, Elisabetta; Tschudi, Christian; Michaeli, Shulamit

      2015-11-01

      Trypanosomatids are protozoan parasites and the causative agent of infamous infectious diseases. These organisms regulate their gene expression mainly at the post-transcriptional level and possess characteristic RNA processing mechanisms. In this study, we analyzed the complete repertoire of Leishmania major small nucleolar (snoRNA) RNAs by performing RNA-seq analysis on RNAs that were affinity-purified using the C/D snoRNA core protein, SNU13, and the H/ACA core protein, NHP2. This study revealed a large collection of C/D and H/ACA snoRNAs, organized in gene clusters generally containing both snoRNA types. Abundant snoRNAs were identified and predicted to guide trypanosome-specific rRNA cleavages. The repertoire of snoRNAs was compared to that of the closely related Trypanosoma brucei, and 80% of both C/D and H/ACA molecules were found to have functional homologues. The comparative analyses elucidated how snoRNAs evolved to generate molecules with analogous functions in both species. Interestingly, H/ACA RNAs have great flexibility in their ability to guide modifications, and several of the RNA species can guide more than one modification, compensating for the presence of single hairpin H/ACA snoRNA in these organisms. Placing the predicted modifications on the rRNA secondary structure revealed hypermodification regions mostly in domains which are modified in other eukaryotes, in addition to trypanosome-specific modifications. PMID:25970223

    20. Required precision of mass and half-life measurements for r-process nuclei planned at future RI-beam facilities

      E-print Network

      Y. Motizuki; T. Tachibana; S. Goriely; H. Koura

      2004-06-17

      In order to understand the r-process nucleosynthesis, we suggest precision required for mass and beta-decay half-life measurements planned at future RI-beam facilities. To satisfy a simple requirement that we put on nuclear model predictions, it is concluded that the detectors for the mass measurements must have a precision of 1sigma ~< 250 keV, and that the detectors for the half-life measurements demand a precision of 1sigma ~< 0.15 ms. Both the above precisions are required at the neutron richness of A/Z = 3.0 at the N=82 shell closure and A/Z = 2.9 at the N=50 shell closure. For the doubly magic nuclide 78Ni, a precision of 1sigma ~< 300 keV and 1sigma ~< 5 ms are required, respectively, for mass and half-life measurements. This analysis aims to provide a first rough guide for ongoing detector developments.

    1. Quantum-dot semiconductor optical amplifiers for high-bit-rate signal processing up to 160 Gb s-1 and a new scheme of 3R regenerators

      NASA Astrophysics Data System (ADS)

      Sugawara, M.; Akiyama, T.; Hatori, N.; Nakata, Y.; Ebe, H.; Ishikawa, H.

      2002-11-01

      This paper presents a theory and simulation of quantum-dot semiconductor optical amplifiers (SOAs) for high-bit-rate optical signal processing. The theory includes spatial isolation of quantum dots, carrier relaxation and excitation among the discrete energy states and the wetting layer, grouping of dots by their optical resonant frequency under the inhomogeneous broadening, and the homogeneous broadening of the single-dot gain, which are all essential to the amplifier performance. We show that high-speed gain saturation occurs due to spectral hole burning under the optical pulse trains up to at least 160 Gb s-1 with negligible pattern effect, and that the self-assembled InGaAs/GaAs quantum-dot SOAs have about two to three orders faster response speed than bulk InGaAsP SOAs, with one order larger gain saturation for the 160 Gb s-1 signals. We also show that switching functions can be realized by the cross gain modulation between the two wavelength channels when the channel separation is within the homogeneous broadening. These results indicate great potential of quantum-dot SOAs for all-optical high-speed switches. As one of their possible applications, we propose a new signal-processing scheme of a `quantum-dot 3R regenerator'.

    2. PV Manufacturing R&D Project Status and Accomplishments under 'In-Line Diagnostics and Intelligent Processing' and 'Yield, Durability and Reliability': Preprint

      SciTech Connect

      Friedman, D. J.; Mitchell, R. L.; Keyes, B. M.; Bower, W. I.; King, R.; Mazer, J.

      2006-05-01

      The PV Manufacturing R&D (PVMR&D) Project conducts cost-shared research and development programs with U.S. PV industry partners. There are currently two active industry partnership activities. ''In-line Diagnostics and Intelligent Processing'', launched in 2002, supports development of new in-line diagnostics and monitoring with real-time feedback for optimal process control and increased yield in the fabrication of PV modules, systems, and other system components. ''Yield, Durability and Reliability'', launched in late 2004, supports enhancement of PV module, system component, and complete system reliability in high-volume manufacturing. A second key undertaking of the PVMR&D Project is the collection and analysis of module production cost-capacity metrics for the U.S. PV industry. In the period from 1992 through 2005, the average module manufacturing cost in 2005 dollars fell 54% (5.7% annualized) to $2.74/Wp, and the capacity increased 18.6-fold (25% annualized) to 253 MW/yr. An experience curve analysis gives progress ratios of 87% and 81%, respectively, for U.S. silicon and thin-film module production.

    3. Introducing the Fission-Fusion Reaction Process: Using a Laser-Accelerated Th Beam to produce Neutron-Rich Nuclei towards the N=126 Waiting Point of the r Process

      E-print Network

      D. Habs; P. G. Thirolf; M. Gross; K. Allinger; J. Bin; A. Henig; D. Kiefer; W. Ma; J. Schreiber

      2010-09-10

      We propose to produce neutron-rich nuclei in the range of the astrophysical r-process around the waiting point N=126 by fissioning a dense laser-accelerated thorium ion bunch in a thorium target (covered by a CH2 layer), where the light fission fragments of the beam fuse with the light fission fragments of the target. Via the 'hole-boring' mode of laser Radiation Pressure Acceleration using a high-intensity, short pulse laser, very efficiently bunches of 232Th with solid-state density can be generated from a Th layer, placed beneath a deuterated polyethylene foil, both forming the production target. Th ions laser-accelerated to about 7 MeV/u will pass through a thin CH2 layer placed in front of a thicker second Th foil closely behind the production target and disintegrate into light and heavy fission fragments. In addition, light ions (d,C) from the CD2 production target will be accelerated as well to about 7 MeV/u, inducing the fission process of 232Th also in the second Th layer. The laser-accelerated ion bunches with solid-state density, which are about 10^14 times more dense than classically accelerated ion bunches, allow for a high probability that generated fission products can fuse again. In contrast to classical radioactive beam facilities, where intense but low-density radioactive beams are merged with stable targets, the novel fission-fusion process draws on the fusion between neutron-rich, short-lived, light fission fragments both from beam and target. The high ion beam density may lead to a strong collective modification of the stopping power in the target, leading to significant range enhancement. Using a high-intensity laser as envisaged for the ELI-Nuclear Physics project in Bucharest (ELI-NP), estimates promise a fusion yield of about 10^3 ions per laser pulse in the mass range of A=180-190, thus enabling to approach the r-process waiting point at N=126.

    4. h x t, r, ,( ) R R r+( ) cos x( )+( )-r sin t r,( )+( )-:= t r,( ) asin

      E-print Network

      Alciatore, David G.

      :=tmax 14 mm:= R 2.25 in 2 := rdime 0.705 in 2 :=tmin 11 mm:= tip curvatures:tip sizes:ball radius: R R x ("Dr. Dave") TP A.22 "Tips" of English technical prooftechnical proof #12;xmax tmin rdime, avg,( ) R 0 minimum cue stick elevation is about: #12;h 0.5 R tmin, rdime, avg,( ) 0.242 in=xmax tmin rdime, avg,( ) R

    5. A comparison of the s- and r-process element evolution in local dwarf spheroidal galaxies and in the Milky Way

      E-print Network

      Gustavo A. Lanfranchi; Francesca Matteucci; Gabriele Cescutti

      2008-02-22

      We study the nucleosynthesis of several neutron capture elements (barium, europium, lanthanum, and yttrium) in local group dwarf spheroidal (dSph) galaxies and in the Milky Way by comparing the evolution of [Ba/Fe], [Eu/Fe], [La/Fe], [Y/Fe], [Ba/Y], [Ba/Eu], [Y/Eu], and [La/Eu] observed in dSph galaxies and in our Galaxy with predictions of detailed chemical evolution models. The models for all dSph galaxies and for the Milky Way are able to reproduce several observational features of these galaxies, such as a series of abundance ratios and the stellar metallicities distributions. The Milky Way model adopts the two-infall scenario, whereas the most important features of the models for the dSph galaxies are the low star-formation rate and the occurrence of intense galactic winds. We predict that the [s-r/Fe] ratios in dSphs are generally different than the corresponding ratios in the Milky Way, at the same [Fe/H] values. This is interpreted as a consequence of the time-delay model coupled with different star formation histories. In particular, the star-formation is less efficient in dSphs than in our Galaxy and it is influenced by strong galactic winds. Our predictions are in very good agreement with the available observational data. The time-delay model for the galactic chemical enrichment coupled with different histories of star formation in different galaxies allow us to succesfully interpret the observed differences in the abundance ratios of s- and r- process elements, as well as of $\\alpha$-elements in dSphs and in the Milky Way. These differences strongly suggest that the main stellar populations of these galaxies could not have had a common origin and, consequently, that the progenitors of local dSphs might not be the same objects as the building blocks of our Galaxy.

    6. Cross section for the process. pi. sup +. pi minus. r arrow. pi0. pi0. in the c. m. s. energy region 0. 55 lt M lt 2 GeV from the reaction. pi. sup minus p r arrow. pi0. pi0. n at 39. 1 GeV/ c

      SciTech Connect

      Apokin, V.D.; Arestov, Y.I.; Belikov, N.I.; Borisov, N.S.; Vasil'ev, A.N.; Grachev, O.A.; Derevshchikov, A.A.; Kazarinov, Y.M.; Liburg, M.Y.; Matafonov, V.N.; and others

      1989-02-01

      The total cross section for the process {pi}{sup +}{pi{minus}}{r arrow}{pi0}{pi0} in the dipion mass region 0.55{lt}{ital M}{lt}2.0 GeV is determined from the peripheral transitions {pi}{sup {minus}}{r arrow}{pi0}{pi0} in carbon and propanediol targets at an initial {pi}{sup {minus}}-meson momentum 39.1 GeV/{ital c}.

    7. A precision measurement of the Z{sup 0} lineshape parameters for the process Z{sup 0} {r_arrow} {tau}{sup +}{tau}{sup {minus}}

      SciTech Connect

      Lahmann, R.

      1996-12-31

      In this dissertation, a measurement of the partial decay width of the process Z{sup 0} {r_arrow} {tau}{sup +}{tau}{sup {minus}} using data collected during 1993 and 1994 at the OPAL detector at CERN is described. The cross sections of this process at three center-of-mass energies near the Z{sup 0} resonance were determined, and from a fit to those cross sections, the mass of the Z{sup 0}, its total decay width and its partial decay width into {tau}{sup +}{tau}{sup {minus}} final states were determined as M{sub Z} = 91.183 {+-} 0.020 GeV, {Lambda}{sub tot} = 2.514 {+-} 0.018 GeV and {Lambda}{sub {tau}{tau}} = 84.54 {+-} 0.59 MeV. Using published results for M{sub Z}, and {Lambda}{sub tot} with higher accuracy, a value for the partial decay width of {Lambda}{sub {tau}{tau}} = 84.02 {+-} 0.20 MeV was obtained. Further using published results for the decay width of the Z{sup 0} into quark pair final states, the invisible decay width of the Z{sup 0} was determined as {Lambda}{sub inv} = 496.9 {+-} 4.1 MeV, and the number of neutrino generations was determined as N{sub {nu}} = 2.974 {+-} 0.025(exp) {+-} 0.007 (m{sub top}, M{sub Higgs}). All results were found to be in good agreement with the Standard Model predictions and were consistent with the assumption of lepton universality within the Standard Model framework.

    8. An $r-$process macronova/kilonova in GRB 060614: evidence for the merger of a neutron star-black hole binary

      E-print Network

      Jin, Zhi-Ping; Wei, Da-Ming

      2015-01-01

      After the jet break at $t\\sim 1.4$ days, the optical afterglow emission of the long-short burst GRB 060614 can be divided into two components. One is the power-law decaying forward shock afterglow emission. The other is an excess of flux in several multi-band photometric observations, which emerges at $\\sim$4 days after the burst, significantly earlier than that observed for a supernova associated with a long-duration GRB. At $t>13.6$ days, the F814W-band flux drops faster than $t^{-3.2}$. Moreover, the spectrum of the excess component is very soft and the luminosity is extremely low. These observed signals are incompatible with those from weak supernovae, but the ejection of $\\sim 0.1~M_\\odot$ of $r-$process material from a black hole-neutron star merger, as recently found in some numerical simulations, can produce it. If this interpretation is correct, it represents the first time that a multi-epoch/band lightcurve of a Li-Paczynski macronova (also known as kilonova) has been obtained and black hole-neutron...

    9. Interpretation of Fracture Toughness and R-Curve Behavior by Direct Observation of Microfracture Process in Ti-Based Dendrite-Containing Amorphous Alloys

      NASA Astrophysics Data System (ADS)

      Jeon, Changwoo; Kim, Choongnyun Paul; Kim, Hyoung Seop; Lee, Sunghak

      2015-04-01

      Fracture properties of Ti-based amorphous alloys containing ductile ? dendrites were explained by directly observing microfracture processes. Three Ti-based amorphous alloys were fabricated by adding Ti, Zr, V, Ni, Al, and Be into a Ti-6Al-4V alloy by a vacuum arc melting method. The effective sizes of dendrites varied from 63 to 104 ?m, while their volume fractions were almost constant within the range from 74 to 76 pct. The observation of the microfracture of the alloy containing coarse dendrites revealed that a microcrack initiated at the amorphous matrix of the notch tip and propagated along the amorphous matrix. In the alloy containing fine dendrites, the crack propagation was frequently blocked by dendrites, and many deformation bands were formed near or in front of the propagating crack, thereby resulting in a zig-zag fracture path. Crack initiation toughness was almost the same at 35 to 36 MPa?m within error ranges in the three alloys because it was heavily affected by the stress applied to the specimen at the time of crack initiation at the crack tip as well as strength levels of the alloys. According to the R-curve behavior, however, the best overall fracture properties in the alloy containing fine dendrites were explained by mechanisms of blocking of the crack growth and crack blunting and deformation band formation at dendrites.

    10. WBSCR22/Merm1 is required for late nuclear pre-ribosomal RNA processing and mediates N7-methylation of G1639 in human 18S rRNA

      PubMed Central

      Haag, Sara; Kretschmer, Jens

      2015-01-01

      Ribosomal (r)RNAs are extensively modified during ribosome synthesis and their modification is required for the fidelity and efficiency of translation. Besides numerous small nucleolar RNA-guided 2?-O methylations and pseudouridinylations, a number of individual RNA methyltransferases are involved in rRNA modification. WBSCR22/Merm1, which is affected in Williams–Beuren syndrome and has been implicated in tumorigenesis and metastasis formation, was recently shown to be involved in ribosome synthesis, but its molecular functions have remained elusive. Here we show that depletion of WBSCR22 leads to nuclear accumulation of 3?-extended 18SE pre-rRNA intermediates resulting in impaired 18S rRNA maturation. We map the 3? ends of the 18SE pre-rRNA intermediates accumulating after depletion of WBSCR22 and in control cells using 3?-RACE and deep sequencing. Furthermore, we demonstrate that WBSCR22 is required for N7-methylation of G1639 in human 18S rRNA in vivo. Interestingly, the catalytic activity of WBSCR22 is not required for 18S pre-rRNA processing, suggesting that the key role of WBSCR22 in 40S subunit biogenesis is independent of its function as an RNA methyltransferase. PMID:25525153

    11. R fluids

      E-print Network

      R. Caimmi

      2007-10-20

      A theory of collisionless fluids is developed in a unified picture, where nonrotating figures with anisotropic random velocity component distributions and rotating figures with isotropic random velocity component distributions, make adjoints configurations to the same system. R fluids are defined and mean and rms angular velocities and mean and rms tangential velocity components are expressed, by weighting on the moment of inertia and the mass, respectively. The definition of figure rotation is extended to R fluids. The generalized tensor virial equations are formulated for R fluids and further attention is devoted to axisymmetric configurations where, for selected coordinate axes, a variation in figure rotation has to be counterbalanced by a variation in anisotropy excess and vice versa. A microscopical analysis of systematic and random motions is performed under a few general hypotheses, by reversing the sign of tangential or axial velocity components of an assigned fraction of particles, leaving the distribution function and other parameters unchanged (Meza 2002). The application of the reversion process to tangential velocity components, implies the conversion of random motion rotation kinetic energy into systematic motion rotation kinetic energy. The application of the reversion process to axial velocity components, implies the conversion of random motion translation kinetic energy into systematic motion translation kinetic energy, and the loss related to a change of reference frame is expressed in terms of systematic (imaginary) motion rotation kinetic energy. A procedure is sketched for deriving the spin parameter distribution (including imaginary rotation) from a sample of observed or simulated large-scale collisionless fluids i.e. galaxies and galaxy clusters.

    12. Cormorants, Humans and the Symposium Process " I IIV principal rmnplain~ agairra~ h r Canadian Press 1995) to clain~sof the whole-

      E-print Network

      Duffy, David Cameron

      releases and articles calling fi)r thc immrdiate halt of the "bird slaughter" at fish ponds and natural- rent norm and the scirnce is disconnected lrom the search tor workahle sohrtions. No matter what

    13. C-C and C-Heteroatom Bond Dissociation Energies in CH3R?C(OH)2: Energetics for Photocatalytic Processes of Organic Diolates on TiO2 Surfaces

      SciTech Connect

      Wang, Tsang-Hsiu; Dixon, David A.; Henderson, Michael A.

      2010-08-26

      The bond energies of a range of gem-diols, CH3R?C(OH)2 (R? = H, F, Cl, Br, CN, NO2, CF3, CH3CH2, CH3CH2CH2, CH3CH2CH2CH2, ((CH3)2)CH, (CH3)3C, ((CH3)2CH)CH2, (CH3CH2)(CH3)CH, C6H5 (CH3CH2)(CH3)CH) which serve as models for binding to a surface have been studied with density functional theory (DFT) and the molecular orbital G3(MP2) methods to provide thermodynamic data for the analysis of the photochemistry of ketones on TiO2. The ultraviolet (UV) photon-induced photodecomposition of adsorbed acetone and 3,3-dimethylbutanone on the rutile TiO2 (110) surface have been investigated with photon stimulated desorption (PSD) and temperature programmed desorption (TPD). The C-CH3 and C-C(R?) bond dissociation energies in CH3R?C(OH)2 were predicted, and our calculated bond dissociation energies are in excellent agreement with the available experimental values. We used a series of isodemic reactions to provide small corrections to the various bond dissociation energies. The calculated bond dissociation energies are in agreement with the observed photodissociation processes except for R? = CF3, suggesting that these processes are under thermodynamic control. For R? = CF3, reaction dynamics also play a role in determining the photodissociation mechanism. The gas phase Brönsted acidities of the gem-diols were calculated. For three molecules, R? = Cl, Br, and NO2, loss of a proton leads to the formation of a complex of acetic acid with the anion Cl-, Br-, and NO2-. The acidities of these three species are very high with the former two having acidities comparable to CF3SO3H. The ketones (R?RC(=O)) are weak Lewis acids except where addition of OH- leads to the dissociation of the complex to form an anion bonded to acetic acid, R' = NO2, Cl, and Br. The X-C bond dissociation energies for a number of X-CO2- species were calculated and these should be useful in correlating with photochemical reactivity studies.

    14. Improved Laboratory Transition Probabilities for Ce II, Application to the Cerium Abundances of the Sun and Five r-process Rich, Metal-Poor Stars, and Rare Earth Lab Data

      E-print Network

      Lawler, J E; Cowan, J J; Ivans, I I; Hartog, E A Den

      2009-01-01

      Recent radiative lifetime measurements accurate to +/- 5% using laser-induced fluorescence (LIF) on 43 even-parity and 15 odd-parity levels of Ce II have been combined with new branching fractions measured using a Fourier transform spectrometer (FTS) to determine transition probabilities for 921 lines of Ce II. This improved laboratory data set has been used to determine a new solar photospheric Ce abundance, log epsilon = 1.61 +/- 0.01 (sigma = 0.06 from 45 lines), a value in excellent agreement with the recommended meteoritic abundance, log epsilon = 1.61 +/- 0.02. Revised Ce abundances have also been derived for the r-process-rich metal-poor giant stars BD+17 3248, CS 22892-052, CS 31082-001, HD 115444 and HD 221170. Between 26 and 40 lines were used for determining the Ce abundance in these five stars, yielding a small statistical uncertainty of 0.01 dex similar to the Solar result. The relative abundances in the metal-poor stars of Ce and Eu, a nearly pure r-process element in the Sun, matches r-process ...

    15. R.I. Borja (Ed.): Multiscal and Multiphysics Processes in Geomechanics, SSGG, pp 149-152. EARTHQUAKE SEQUENCE CALCULATIONS WITH DYNAMIC

      E-print Network

      ,2 , and James R. Rice3 1 Division of Geological and Planetary Sciences California Institute of Technology 1200 E California Institute of Technology 1200 E. California Blvd. Pasadena CA 91125 e-mail: lapusta lower shear stresses, and lock with the final stress only modestly lower than the initial value. [4], [5

    16. Processes Affecting Tropospheric Ozone Inferred from Ozonesonde and Other Tracer Data from the R/V R H Brown Atlantic Cruise (37N-34S) in January-February 1999

      NASA Technical Reports Server (NTRS)

      Thompson, Anne M.; Doddridge, B. G.; Luke, W. T.; Johnson, J. E.; Witte, J. C.; Reynolds, R. M.; Johnson, B.; Oltmans, S. J.

      1999-01-01

      During the Aerosols-99 trans-Atlantic cruise from Norfolk, VA, to Cape Town, South Africa, 22 ozonesondes were launched from the NOAA R/V R H Brown between 17 Jan and 6 Feb 1999, with all sondes but one reaching 30 km. A composite of ozone profiles along the transect shows high free tropospheric ozone (up to 100 ppbv at 9 km) between 5N and 20S, a coherent feature straddling either side of the ITCZ. Latitudinal variations of tropospheric ozone are interpreted using correlative measurements of surface ozone, CO, water vapor, and aerosol optical thickness (column absorbance) measured from the ship. Elevated ozone in the lower troposphere results from photochemical reactions of precursors emitted by biomass burning north of the ITCZ. However, the greatest ozone mixing ratios are in the mid-troposphere south of the ITCZ, which gives evidence of interhemispheric transport. Column-integrated tropospheric ozone, 35 DU from 0-16 km, agrees with that derived from the TOMS satellite by the modified-residual method [Thompson and Hudson, 1999]. NCEP wind fields, ship-launched radiosondes and back trajectories are consistent with a picture of recirculating air parcels centered in the tropical Atlantic region which is identified with the maximum wave-one amplitude in total ozone seen in sondes and by satellite.

    17. Nile: A Query Processing Engine for Data Streams W. G. Aref, A. K. Elmagarmid, M. H. Ali, A. C. Catlin, M. G. Elfeky, M. Eltabak, T. Ghanem, R.

      E-print Network

      Ilyas, Ihab Francis

      Nile: A Query Processing Engine for Data Streams W. G. Aref, A. K. Elmagarmid, M. H. Ali, A. C. Introduction This demonstration presents the design of "STEAM", Purdue Boiler Makers' stream database system, the demonstration will focus on the query processing part, "Nile". Nile extends the query processor engine

    18. E.R.I.E. and Process Education (With Reference to M:ACOS and SRA-SSLU). A Summary Statement.

      ERIC Educational Resources Information Center

      Ripple, Richard E.

      A summary position statement of the Eastern Regional Institute for Education presents its mission of changing elementary education toward the direction of process education. The first of three basic parts reviews the three completed chapters of a monograph, "What is Process Education? An Emerging Rational Position," in terms of a definition of…

    19. A COMPOSITE HOLLOW FIBER MEMBRANE-BASED PERVAPORATION PROCESS FOR SEPARATION OF VOCS FROM AQUEOUS SURFACTANT SOLUTIONS. (R825511C027)

      EPA Science Inventory

      The separation and recovery of VOCs from surfactant-containing aqueous solutions by a composite hollow fiber membrane-based pervaporation process has been studied. The process employed hydrophobic microporous polypropylene hollow fibers having a thin plasma polymerized silicon...

    20. Phil. Trans. R. Soc. A. article template Phil. Trans. R. Soc. A.

      E-print Network

      Bretherton, Chris

      Phil. Trans. R. Soc. A. article template Phil. Trans. R. Soc. A. doi:10.1098/not yet assigned 1. Parameterizations of these *Author for correspondence (breth@washington.edu) #12;Phil. Trans. R. Soc. A. processes

    1. Process Efficiency Measurements in the Laser Engineered Net Shaping Process

      E-print Network

      DuPont, John N.

      Process Efficiency Measurements in the Laser Engineered Net Shaping Process R.R. UNOCIC and J.N. DuPONT, Columbus, OH 43210. J.N. DuPONT, Associate Professor, is with the Materials Science and Engineering

    2. Fate of R parity

      SciTech Connect

      Perez, Pavel Fileviez; Spinner, Sogee

      2011-02-01

      The possible origin of the R-parity-violating interactions in the minimal supersymmetric standard model and its connection to the radiative symmetry-breaking mechanism is investigated in the context of the simplest model where the radiative symmetry-breaking mechanism can be implemented. We find that, in the majority of the parameter space, R parity is spontaneously broken at the low scale. These results hint that R-parity-violating processes could be observed at the Large Hadron Collider, if supersymmetry is realized in nature.

    3. AN EXPERIMENTAL INVESTIGATION INTO THE EFFECT OF PROCESS CONDITIONS ON THE MASS CONCENTRATION OF CUTTING FLUID MIST IN TURNING. (R825370C057)

      EPA Science Inventory

      Cutting fluid mists that are generated during machining processes represent a significant waste stream as well as a health hazard to humans. Epidemiological studies have shown a link between worker exposure to cutting fluid mist and an increase in respiratory ailments and seve...

    4. Process Flexibility: a Survey of Contemporary M.H. Schonenberg, R.S. Mans, N.C. Russell, N.A. Mulyar

      E-print Network

      van der Aalst, Wil

      can be achieved and we propose an extensive taxonomy of flexibility. This taxonomy is subsequently on a particular notation (e.g., XPDL, BPEL, BPMN, etc.) and these notations typically abstract from flexibility kinds of flexibility are needed during the BPM life cycle of a process. Based on an extensive survey

    5. Effective Reuse via Modeling, Managing, and Searching of Business Process Nanjangud C. Narendra, Karthikeyan Ponnalagu, G.R. Gangadharan, Hong-Linh Truong, Schahram Dustdar,

      E-print Network

      Dustdar, Schahram

      repositories, rather than develop them from scratch. But this has been hampered by some issues that have assets as variants and versions in repositories. Second, there is no formal means to compare between for modeling, analyzing, and searching business process assets in a repository for enhancing reuse. We

    6. Eytan, R. I. and M. E. Hellberg. 2010. Nuclear and mitochondrial sequence data reveal and conceal different demographic histories and population genetic processes in Caribbean reef

      E-print Network

      Hellberg, Michael E.

      different demographic histories and population genetic processes in Caribbean reef fishes. Evolution, in press. Mitochondrial and nuclear sequence data should recover historical demographic events at different by combining both nuclear and mitochondrial data were we able to recover the complex demographic history

    7. Quarterly Journal of the Royal Meteorological Society Q. J. R. Meteorol. Soc. 136: 333353, January 2010 Part B Modelling convective processes during the suppressed phase

      E-print Network

      Chaboureau, Jean-Pierre

      is associated with a predominance of shallow convection. All SCMs produce adequate amounts of shallow convection. A gradual transition from shallow to deep convection is simulated by the CRMs and the wetter SCMs during 2010 Part B Modelling convective processes during the suppressed phase of a Madden­Julian oscillation

    8. Test Review: R. W. Keith "SCAN-3 for Adolescents and Adults--Tests for Auditory Processing Disorders". San Antonio, TX: Pearson, 2009

      ERIC Educational Resources Information Center

      Lovett, Benjamin J.; Johnson, Theodore L.

      2010-01-01

      The SCAN-3 is a battery of tasks used for the screening and diagnosis of auditory processing disorder. It is available in two versions, one for children (the SCAN-3: C) and one for adolescents and adults (the SCAN-3: A); the latter version of the SCAN-3 is reviewed in this article, although it is very similar to the child version. The primary…

    9. This document contains the draft version of the following paper: S.K. Gupta, Y.S. Chen, S. Feng, and R. Sriram. A system for generating process

      E-print Network

      Gupta, Satyandra K.

      and materials using either their own previous experience, or the experience of the manufacturing engineer. Most, manufacturing engineers can use their knowledge of the manufacturing processes and materials to suggest that manufacturing engineers may not be considering all Journal of Manufacturing Systems, 22(1):28--45, 2003 #12

    10. Effects of Low Frequency Repetitive Transcranial Magnetic Stimulation (rTMS) on Gamma Frequency Oscillations and Event-Related Potentials during Processing of Illusory Figures in Autism

      ERIC Educational Resources Information Center

      Sokhadze, Estate M.; El-Baz, Ayman; Baruth, Joshua; Mathai, Grace; Sears, Lonnie; Casanova, Manuel F.

      2009-01-01

      Previous studies by our group suggest that the neuropathology of autism is characterized by a disturbance of cortical modularity. In this model a decrease in the peripheral neuropil space of affected minicolumns provides for an inhibitory deficit and a readjustment in their signal to noise bias during information processing. In this study we…

    11. Assessment of Conative Educational Processes and Outcomes: Status Report of Empirical Studies. Project 2.3: Enhancing the Utility of Performance Assessments: Domain-Independent R&D.

      ERIC Educational Resources Information Center

      Snow, Richard E.; Jackson, Douglas N.

      Research planned to improve understanding of conative educational processes and outcomes is described. Over the past year, literature reviews have been conducted aimed at defining categories of assessment of student persistence, freedom from distraction, engagement, and other school-and-work related attitudes and motivations, both as learning…

    12. Bacterial Diversity Analysis during the Fermentation Processing of Traditional Chinese Yellow Rice Wine Revealed by 16S rDNA 454 Pyrosequencing.

      PubMed

      Fang, Ruo-Si; Dong, Ya-Chen; Chen, Feng; Chen, Qi-He

      2015-10-01

      Rice wine is a traditional Chinese fermented alcohol drink. Spontaneous fermentation with the use of the Chinese starter and wheat Qu lead to the growth of various microorganisms during the complete brewing process. It's of great importance to fully understand the composition of bacteria diversity in rice wine in order to improve the quality and solve safety problems. In this study, a more comprehensive bacterial description was shown with the use of bacteria diversity analysis, which enabled us to have a better understanding. Rarefaction, rank abundance, alpha Diversity, beta diversity and principal coordinates analysis simplified their complex bacteria components and provide us theoretical foundation for further investigation. It has been found bacteria diversity is more abundant at mid-term and later stage of brewing process. Bacteria community analysis reveals there is a potential safety hazard existing in the fermentation, since most of the sequence reads are assigned to Enterobacter (7900 at most) and Pantoea (7336 at most), followed by Staphylococcus (2796 at most) and Pseudomonas (1681 at most). Lactic acid bacteria are rare throughout the fermentation process which is not in accordance with other reports. This work may offer us an opportunity to investigate micro ecological fermentation system in food industry. PMID:26409170

    13. The Earth's magnetosphere is 165 R(sub E) long: Self-consistent currents, convection, magnetospheric structure, and processes for northward interplanetary magnetic field

      NASA Technical Reports Server (NTRS)

      Fedder, J. A.; Lyon, J. G.

      1995-01-01

      The subject of this paper is a self-consistent, magnetohydrodynamic numerical realization for the Earth's magnetosphere which is in a quasi-steady dynamic equilibrium for a due northward interplanetary magnetic field (IMF). Although a few hours of steady northward IMF are required for this asymptotic state to be set up, it should still be of considerable theoretical interest because it constitutes a 'ground state' for the solar wind-magnetosphere interaction. Moreover, particular features of this ground state magnetosphere should be observable even under less extreme solar wind conditions. Certain characteristics of this magnetosphere, namely, NBZ Birkeland currents, four-cell ionospheric convection, a relatively weak cross-polar potential, and a prominent flow boundary layer, are widely expected. Other characteristics, such as no open tail lobes, no Earth-connected magnetic flux beyond 155 R(sub E) downstream, magnetic merging in a closed topology at the cusps, and a 'tadpole' shaped magnetospheric boundary, might not be expected. In this paper, we will present the evidence for this unusual but interesting magnetospheric equilibrium. We will also discuss our present understanding of this singular state.

    14. The Earth`s magnetosphere is 165 R{sub E} long: Self-consistent currents, convection, magnetospheric structure, and processes for northward interplanetary magnetic field

      SciTech Connect

      Fedder, J.A.; Lyon, J.G.

      1995-03-01

      The subject of this paper is a self-consistent, magnetohydrodynamic numerical realization for the Earth`s magnetosphere which is in a quasi-steady dynamic equilibrium for a due northward interplanetary magnetic field (IMF). Although a few hours of steady northward IMF are required for this asymptotic state to be set up, it should still be of considerable theoretical interest because it constitutes a `ground state` for the solar wind-magnetosphere interaction. Moreover, particular features of this ground state magnetosphere should be observable even under less extreme solar wind conditions. Certain characteristics of this magnetosphere, namely, NBZ Birkeland currents, four-cell ionospheric convection, a relatively weak cross-polar potential, and a prominent flow boundary layer, are widely expected. Other characteristics, such as no open tail lobes, no Earth-connected magnetic flux beyond 155 R(sub E) downstream, magnetic merging in a closed topology at the cusps, and a `tadpole` shaped magnetospheric boundary, might not be expected. In this paper, we will present the evidence for this unusual but interesting magnetospheric equilibrium. We will also discuss our present understanding of this singular state.

    15. Process for functionalizing alkanes

      DOEpatents

      Bergman, R.G.; Janowicz, A.H.; Periana, R.A.

      1988-05-24

      Process for functionalizing saturated hydrocarbons comprises: (a) reacting said saturated hydrocarbons of the formula: R[sub 1]H wherein H represents a hydrogen atom; and R[sub 1] represents a saturated hydrocarbon radical, with a metal complex of the formula: CpRh[P(R[sub 2])[sub 3

    16. Dynamic mixing processes in spin triads of "breathing crystals" Cu(hfac)(2)L(R): a multifrequency EPR study at 34, 122 and 244 GHz.

      PubMed

      Fedin, Matvey V; Veber, Sergey L; Romanenko, Galina V; Ovcharenko, Victor I; Sagdeev, Renad Z; Klihm, Gudrun; Reijerse, Edward; Lubitz, Wolfgang; Bagryanskaya, Elena G

      2009-08-21

      Spin triads of copper(ii) with two nitroxides are responsible for the magnetic anomalies in a new family of molecular-magnetic compounds called "breathing crystals". We have shown previously that electron paramagnetic resonance (EPR) spectroscopy allows one to investigate the peculiarities of these systems and obtain valuable information on exchange interactions governing the magnetic anomalies. One of the key processes revealed is the dynamic mixing between different spin multiplets that leads to a coalescence of individual EPR lines at high temperatures. The rates of the mixing were found to be fast at EPR frequencies between 9 and 94 GHz. In the present work, we expose the spin triads to higher microwave frequencies of up to 244 GHz in order to reach the conditions of intermediate or slow mixing rates. Three representatives of the family of breathing crystals have been studied. Based on the simulations of EPR data at 34, 122 and 244 GHz, the rates of the mixing processes have been estimated and conclusions on their character and temperature dependence have been drawn. The insights from high-field EPR clarify previously obtained results and aid in the further development of EPR approaches for studying these and similar systems. It is suggested that the static and dynamic Jahn-Teller effects may play an important role in the mechanisms governing the observed spin exchange effects. PMID:19639139

    17. Re-interpreting R, R and R

      NASA Astrophysics Data System (ADS)

      Griffin, Elizabeth M.

      2015-08-01

      Why are we so much more aware of environmental issues today than was the case 100-150 years ago, when particle-laden smoke belched out of chimneys, modes of travel (both near and distant) were best sellers, and fluorescent lighting made it possible to work all night as well as all day? Are we now paying the price of the Industrial Revolution?Not altogether. Along with the side-effects of all such "improvements" have come two other parallel but crucial developments: (1) technology to control harmful emissions, and (2) increased populations, each demanding - and getting - freedom of choice, as did their recent ancestors.The Environmentalist's Motto, the Three Rs (Re-duce, Re-use, Re-cycle) is perfectly clear: the prime action in all cases is REDUCE. The individual, however, looks to "Them" to make by-laws, or install efficient road lighting and controls just in the the public domain. The individual rarely accepts that the R, R, R message applies also to him or her, and to his or her family. Where then is freedom of choice? We discuss the alternative Three Rs (Rights, Recreations, Responsibilities) of the Individual's Motto, and try to put them in working order. To do that, we discuss the impacts of night-time lighting on parties other than astronomers.

    18. R/parallel – speeding up bioinformatics analysis with R

      PubMed Central

      Vera, Gonzalo; Jansen, Ritsert C; Suppi, Remo L

      2008-01-01

      Background R is the preferred tool for statistical analysis of many bioinformaticians due in part to the increasing number of freely available analytical methods. Such methods can be quickly reused and adapted to each particular experiment. However, in experiments where large amounts of data are generated, for example using high-throughput screening devices, the processing time required to analyze data is often quite long. A solution to reduce the processing time is the use of parallel computing technologies. Because R does not support parallel computations, several tools have been developed to enable such technologies. However, these tools require multiple modications to the way R programs are usually written or run. Although these tools can finally speed up the calculations, the time, skills and additional resources required to use them are an obstacle for most bioinformaticians. Results We have designed and implemented an R add-on package, R/parallel, that extends R by adding user-friendly parallel computing capabilities. With R/parallel any bioinformatician can now easily automate the parallel execution of loops and benefit from the multicore processor power of today's desktop computers. Using a single and simple function, R/parallel can be integrated directly with other existing R packages. With no need to change the implemented algorithms, the processing time can be approximately reduced N-fold, N being the number of available processor cores. Conclusion R/parallel saves bioinformaticians time in their daily tasks of analyzing experimental data. It achieves this objective on two fronts: first, by reducing development time of parallel programs by avoiding reimplementation of existing methods and second, by reducing processing time by speeding up computations on current desktop computers. Future work is focused on extending the envelope of R/parallel by interconnecting and aggregating the power of several computers, both existing office computers and computing clusters. PMID:18808714

    19. Mutation of EMG1 causing Bowen–Conradi syndrome results in reduced cell proliferation rates concomitant with G2/M arrest and 18S rRNA processing delay

      PubMed Central

      Armistead, Joy; Hemming, Richard; Patel, Nehal; Triggs-Raine, Barbara

      2014-01-01

      Bowen–Conradi syndrome (BCS) is a lethal autosomal recessive disorder caused by a D86G substitution in the protein, Essential for Mitotic Growth 1 (EMG1). EMG1 is essential for 18S rRNA maturation and 40S ribosome biogenesis in yeast, but no studies of its role in ribosome biogenesis have been done in mammals. To assess the effect of the EMG1 mutation on cell growth and ribosomal biogenesis in humans, we employed BCS patient cells. The D86G substitution did not interfere with EMG1 nucleolar localization. In BCS patient lymphoblasts, cells accumulated in G2/M, resulting in reduced proliferation rates; however, patient fibroblasts showed normal proliferation. The rate of 18S rRNA processing was consistently delayed in patient cells, although this did not lead to a difference in the levels of 40S ribosomes, or a change in protein synthesis rates. These results demonstrate that as in yeast, EMG1 in mammals has a role in ribosome biogenesis. The obvious phenotype in lymphoblasts compared to fibroblasts suggests a greater need for EMG1 in rapidly dividing cells. Tissue-specific effects have been seen in other ribosomal biogenesis disorders, and it seems likely that the impact of EMG1 deficiency would be larger in the rapidly proliferating cells of the developing embryo.

    20. r Human Brain Mapping 32:665675 (2011) r Dissociable Brain States Linked to Common and

      E-print Network

      Thompson-Schill, Sharon

      2011-01-01

      r Human Brain Mapping 32:665­675 (2011) r Dissociable Brain States Linked to Common and Creative, Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania r r Abstract: Studies of conceptual processing have revealed that the prefrontal cortex is implicated in close-ended, deliberate

    1. Developments in CD-R

      NASA Astrophysics Data System (ADS)

      Verhoeven, J. A. T.; Mischke, Wlodek S.

      2001-02-01

      A review of recent developments in CD-R technology is given. This covers the physical design principles of the disc together with its production methods. We review all the subsequent manufacturing steps. The relevance of groove replication, substrate conditioning, dye solution and solvents, spinning methods, dye coating process conditions, dye layer drying, sputtering and lacquer coating on the CD-R disc performance are presented. The differences in the recording mechanism for several types of dyes are illustrated. The two modified new phthalocyanine and cyanine processes are described. Some technological implications for higher density recordable formats like DVD-R will be given.

    2. WHAT'S INSIDE R About the Concurrent Enrollment 2

      E-print Network

      Barrash, Warren

      WHAT'S INSIDE R About the Concurrent Enrollment 2 Program R Adjunct Instructor Information Concurrent Enrollment Faculty Orientation 2 Professional Development 2 Faculty ID Card 3 myBoiseState Account Evaluations by Students 6 R Student Enrollment and Withdrawal 6 Process R Scholarships 7 R Student Benefits 8

    3. R2R-printed inverted OPV modules - towards arbitrary patterned designs

      NASA Astrophysics Data System (ADS)

      Välimäki, M.; Apilo, P.; Po, R.; Jansson, E.; Bernardi, A.; Ylikunnari, M.; Vilkman, M.; Corso, G.; Puustinen, J.; Tuominen, J.; Hast, J.

      2015-05-01

      We describe the fabrication of roll-to-roll (R2R) printed organic photovoltaic (OPV) modules using gravure printing and rotary screen-printing processes. These two-dimensional printing techniques are differentiating factors from coated OPVs enabling the direct patterning of arbitrarily shaped and sized features into visual shapes and, increasing the freedom to connect the cells in modules. The inverted OPV structures comprise five layers that are either printed or patterned in an R2R printing process. We examined the rheological properties of the inks used and their relationship with the printability, the compatibility between the processed inks, and the morphology of the R2R-printed layers. We also evaluate the dimensional accuracy of the printed pattern, which is an important consideration in designing arbitrarily-shaped OPV structures. The photoactive layer and top electrode exhibited excellent cross-dimensional accuracy corresponding to the designed width. The transparent electron transport layer extended 300 µm beyond the designed values, whereas the hole transport layer shrank 100 µm. We also examined the repeatability of the R2R fabrication process when the active area of the module varied from 32.2 cm2 to 96.5 cm2. A thorough layer-by-layer optimization of the R2R printing processes resulted in realization of R2R-printed 96.5 cm2 sized modules with a maximum power conversion efficiency of 2.1% (mean 1.8%) processed with high functionality.

    4. R2R-printed inverted OPV modules--towards arbitrary patterned designs.

      PubMed

      Välimäki, M; Apilo, P; Po, R; Jansson, E; Bernardi, A; Ylikunnari, M; Vilkman, M; Corso, G; Puustinen, J; Tuominen, J; Hast, J

      2015-06-01

      We describe the fabrication of roll-to-roll (R2R) printed organic photovoltaic (OPV) modules using gravure printing and rotary screen-printing processes. These two-dimensional printing techniques are differentiating factors from coated OPVs enabling the direct patterning of arbitrarily shaped and sized features into visual shapes and, increasing the freedom to connect the cells in modules. The inverted OPV structures comprise five layers that are either printed or patterned in an R2R printing process. We examined the rheological properties of the inks used and their relationship with the printability, the compatibility between the processed inks, and the morphology of the R2R-printed layers. We also evaluate the dimensional accuracy of the printed pattern, which is an important consideration in designing arbitrarily-shaped OPV structures. The photoactive layer and top electrode exhibited excellent cross-dimensional accuracy corresponding to the designed width. The transparent electron transport layer extended 300 µm beyond the designed values, whereas the hole transport layer shrank 100 µm. We also examined the repeatability of the R2R fabrication process when the active area of the module varied from 32.2 cm(2) to 96.5 cm(2). A thorough layer-by-layer optimization of the R2R printing processes resulted in realization of R2R-printed 96.5 cm(2) sized modules with a maximum power conversion efficiency of 2.1% (mean 1.8%) processed with high functionality. PMID:25951787

    5. Effect of Processing on Synthesis and Dielectric Properties of Lead free (Bi0.98R0.02)0.5Na0.5TiO3 Ceramics

      NASA Astrophysics Data System (ADS)

      Pal, Vijayeta; Dwivedi, R. K.

      2015-02-01

      In the present work, an effort has been made to synthesize (Bi1-xRx)0.5Na0.5TiO3 (BRNT) system with compositions x = 0 & 0.02, where R = La, Nd and Gd by Semi-Wet Technique. Processing of the composition with x = 0 has been optimized by two precursor solution one by citric acid and other by ethylene glycol. The XRD patterns of these samples, prepared by ethylene glycol precursor solution, have shown pure phase of perovskite structure with a rhombohedral symmetry. The studies on structure, phase transitions and dielectric properties for all the samples have been carried out over the temperature range from RT to 450 °C at 100 kHz frequency. It has been observed that two phase transitions (i) ferroelectric to anti-ferroelectric and (ii) anti ferroelectric to paraelectric occur in all the samples. All samples exhibit a modified Curie-Weiss law above Tc. A linear fitting of the modified Curie- Weiss law to the experimental data shows diffuse type transition. The dielectric properties of BNT ceramics have been found to be improved with the substitution of rare earth elements.

    6. e n g e n i o u s w i n t e r 2 0 0 3 1 A transistor in a given process technology is usually characterized by its unity-gain frequency shown as fT . This is the frequency at which the cur-

      E-print Network

      Haile, Sossina M.

      e n g e n i o u s w i n t e r 2 0 0 3 1 A transistor in a given process technology is usually ratio of the output current to input current) of a transistor drops to unity. While the unity-gain frequency of a transistor provides an approximate measure to compare transistors in different technologies

    7. FINAL REPORT DETERMINATION OF THE PROCESSING RATE OF RPP WTP HLW SIMULANTS USING A DURAMELTER J 1000 VITRIFICATION SYSTEM VSL-00R2590-2 REV 0 8/21/00

      SciTech Connect

      KRUGER AA; MATLACK KS; KOT WK; PEREZ-CARDENAS F; PEGG IL

      2011-12-29

      This report provides data, analysis, and conclusions from a series of tests that were conducted at the Vitreous State Laboratory of The Catholic University of America (VSL) to determine the melter processing rates that are achievable with RPP-WTP HLW simulants. The principal findings were presented earlier in a summary report (VSL-00R2S90-l) but the present report provides additional details. One of the most critical pieces of information in determining the required size of the RPP-WTP HLW melter is the specific glass production rate in terms of the mass of glass that can be produced per unit area of melt surface per unit time. The specific glass production rate together with the waste loading (essentially, the ratio of waste-in to glass-out, which is determined from glass formulation activities) determines the melt area that is needed to achieve a given waste processing rate with due allowance for system availability. As a consequence of the limited amount of relevant information, there exists, for good reasons, a significant disparity between design-base specific glass production rates for the RPP-WTP LAW and HLW conceptual designs (1.0 MT/m{sup 2}/d and 0.4 MT/m{sup 2}/d, respectively); furthermore, small-scale melter tests with HLW simulants that were conducted during Part A indicated typical processing rates with bubbling of around 2.0 MT/m{sup 2}/d. This range translates into more than a factor of five variation in the resultant surface area of the HLW melter, which is clearly not without significant consequence. It is clear that an undersized melter is undesirable in that it will not be able to support the required waste processing rates. It is less obvious that there are potential disadvantages associated with an oversized melter, over and above the increased capital costs. A melt surface that is consistently underutilized will have poor cold cap coverage, which will result in increased volatilization from the melt (which is generally undesirable) and increased plenum temperatures due to increased thermal radiation from the melt surface (which mayor may not be desirable but the flexibility to choose may be lost). Increased volatilization is an issue both in terms of the increased challenge to the off-gas system as well as for the ability to effectively close the recycle loops for volatile species that must be immobilized in the glass product, most notably technetium and cesium. For these reasons, improved information is needed on the specific glass production rates of RPP-WTP HLW streams in DuraMelterJ systems over a range of operating conditions. Unlike the RPP-WTP LAW program, for which a pilot melter system to provide large-scale throughout information is already in operation, there is no comparable HLW activity; the results of the present study are therefore especially important. This information will reduce project risk by reducing the uncertainty associated with the amount of conservatism that mayor may not be associated with the baseline RPP-WTP HLW melter sizing decision. After the submission of the first Test Plan for this work, the RPP-WTP requested revisions to include tests to determine the processing rates that are achievable without bubbling, which was driven by the potential advantages of omitting bubblers from the HLW melter design in terms of reduced maintenance. A further objective of this effort became the determination of whether the basis of design processing rate could be achieved without bubbling. Ideally, processing rate tests would be conducted on a full-scale RPP-WTP melter system with actual HLW materials, but that is clearly unrealistic during Part B1. As a practical compromise the processing rate determinations were made with HL W simulants on a DuraMelter J system at as close to full scale as possible and the DM 1000 system at VSL was selected for that purpose. That system has a melt surface area of 1.2 m{sup 2}, which corresponds to about one-third scale based on the specific glass processing rate of 0.4 MT/m{sup 2}/d assumed in the RPP-WTP HLW conceptual design, but would correspon

    8. The R2R3-Myb transcription fators of cotton: SNP characterization, chromosomal assignment, and phylogenetic analysis

      Technology Transfer Automated Retrieval System (TEKTRAN)

      The R2R3-Myb transcription factors are involved in many plant physiological and biochemical processes including regulation of trichome length and density in Arabidopsis. In cotton, Gossypium spp.,the developmental regulation of some R2R3-Myb transcription factors are related to fiber differentiatio...

    9. Mineral Processing Research Louisiana State University

      E-print Network

      Pike, Ralph W.

      Mineral Processing Research Institute Louisiana State University Advanced Process Analysis System User's Manual and Tutorial for the Alkylation Process Derya Ozyurt Ralph W. Pike Jack R. Hopper Janardhana R. Punuru Carl L. Yaws Copyright 2001 Louisiana State University May 1,2001 Process Specification

    10. ~ncf~r n R f ll R A r r o N BENDIX SYSTEMS DIVISION ANN ARBOR, MICH.

      E-print Network

      Rathbun, Julie A.

      ·~ncf~r n R f ll R A r r o N 5/23/66 BENDIX SYSTEMS DIVISION ANN ARBOR, MICH. ALSEP Experiment DIVISION ANN ARBOR, MICH. ALSE'P Experiment Power Line Protection NO. REV. NO. r~n#'~ ATM... 289 { fl H f 0

    11. 77 FR 1656 - Proposed Establishment of Restricted Areas R-5402, R-5403A, R-5403B, R-5403C, R-5403D, R-5403E, R...

      Federal Register 2010, 2011, 2012, 2013, 2014

      2012-01-11

      ... November 28, 2011 (76 FR 72869), scheduled to close on January 12, 2012, is extended until February 12... Register published on April 11, 2000 (65 FR 19477-78) or you may visit http://DocketsInfo.dot.gov . Docket... Areas R-5402, R-5403A, R-5403B, R- 5403C, R-5403D, R-5403E, R-5403F; Devils Lake, ND (76 FR...

    12. Expansion and diversification of the Populus R2R3-MYB family of transcription factors.

      PubMed

      Wilkins, Olivia; Nahal, Hardeep; Foong, Justin; Provart, Nicholas J; Campbell, Malcolm M

      2009-02-01

      The R2R3-MYB proteins comprise one of the largest families of transcription factors in plants. R2R3-MYB family members regulate plant-specific processes, such as the elaboration of specialized cell types, including xylem, guard cells, trichomes, and root hairs, and the biosynthesis of specialized branches of metabolism, including phenylpropanoid biosynthesis. As such, R2R3-MYB family members are hypothesized to contribute to the emergence of evolutionary innovations that have arisen in specific plant lineages. As a first step in determining the role played by R2R3-MYB family members in the emergence of lineage-specific innovations in the genus Populus, the entire Populus trichocarpa R2R3-MYB family was characterized. The Populus R2R3-MYB complement is much larger than that found in other angiosperms with fully sequenced genomes. Phylogenetic analyses, together with chromosome placement, showed that the expansion of the Populus R2R3-MYB family was not only attributable to whole genome duplication but also involved selective expansion of specific R2R3-MYB clades. Expansion of the Populus R2R3-MYB family prominently involved members with expression patterns that suggested a role in specific components of Populus life history, including wood formation and reproductive development. An expandable compendium of microarray-based expression data (PopGenExpress) and associated Web-based tools were developed to better enable within- and between-species comparisons of Populus R2R3-MYB gene expression. This resource, which includes intuitive graphic visualization of gene expression data across multiple tissues, organs, and treatments, is freely available to, and expandable by, scientists wishing to better understand the genome biology of Populus, an ecologically dominant and economically important forest tree genus. PMID:19091872

    13. 1,2-dichlorohexafluoro-cyclobutane (1,2-c-C4F6Cl2, R-316c) a Potent Ozone Depleting Substance and Greenhouse Gas: Atmospheric Loss Processes, Lifetimes, and Ozone Depletion and Global Warming Potentials for the (E)- and (Z)- Stereoisomers

      NASA Astrophysics Data System (ADS)

      Papadimitriou, V. C.; McGillen, M. R.; Smith, S. C.; Jubb, A. M.; Portmann, R. W.; Hall, B. D.; Fleming, E. L.; Jackman, C. H.; Burkholder, J. B.

      2013-12-01

      1,2-dichlorohexafluoro-cyclobutane (1,2-c-C4F6Cl2, R-316c) is currently used in medical applications, as inhaled non-immobilizer amnesiac, in limited quantities and has recently been considered as a potential chlorofluoro/hydrofluoro-carbon replacement compound. R-316c usage is not restricted under the Montreal Protocol, although, R-316c represents a potent ozone depleting substance and greenhouse gas. In this work, a combination of laboratory studies of infrared absorption spectra, kinetic, and photolysis processes were performed for the (E)- and (Z)- stereoisomers of R-316c to enable an evaluation of their atmospheric lifetimes, ozone depletion (ODPs) and global warming potentials (GWPs). More specifically, O(1D), OH, and O3 reaction rate coefficients, as well as UV absorption spectra, including temperature dependence, and photolysis quantum yields and stable photolysis end-products were determined. The results from these studies will be presented. R-316c lifetimes and ODPs were evaluated using a 2-D atmospheric chemical model. Both isomers of R-316c were shown to be long-lived substances, primarily removed in the stratosphere by UV photolysis, with large ODPs, >0.3. A line-by-line radiative transfer model was used to calculate radiative efficiencies and, thus, GWPs. The GWPs for both isomers are substantial, ~5000 on the 100-year time horizon. In this presentation, we highlight the need for a thorough evaluation of the atmospheric processing of proposed replacement substances prior to usage and their inevitable emission into the atmosphere. The results of such studies enable policy makers to make informed decisions.

    14. 1,2-Dichlorohexafluoro-Cyclobutane (1,2-c-C4F6Cl2, R-316c) a Potent Ozone Depleting Substance and Greenhouse Gas: Atmospheric Loss Processes, Lifetimes, and Ozone Depletion and Global Warming Potentials for the (E) and (Z) stereoisomers

      NASA Technical Reports Server (NTRS)

      Papadimitriou, Vassileios C.; McGillen, Max R.; Smith, Shona C.; Jubb, Aaron M.; Portmann, Robert W.; Hall, Bradley D.; Fleming, Eric L.; Jackman, Charles H.; Burkholder, James B.

      2013-01-01

      The atmospheric processing of (E)- and (Z)-1,2-dichlorohexafluorocyclobutane (1,2-c-C4F6Cl2, R-316c) was examined in this work as the ozone depleting (ODP) and global warming (GWP) potentials of this proposed replacement compound are presently unknown. The predominant atmospheric loss processes and infrared absorption spectra of the R-316c isomers were measured to provide a basis to evaluate their atmospheric lifetimes and, thus, ODPs and GWPs. UV absorption spectra were measured between 184.95 to 230 nm at temperatures between 214 and 296 K and a parametrization for use in atmospheric modeling is presented. The Cl atom quantum yield in the 193 nm photolysis of R- 316c was measured to be 1.90 +/- 0.27. Hexafluorocyclobutene (c-C4F6) was determined to be a photolysis co-product with molar yields of 0.7 and 1.0 (+/-10%) for (E)- and (Z)-R-316c, respectively. The 296 K total rate coefficient for the O(1D) + R-316c reaction, i.e., O(1D) loss, was measured to be (1.56 +/- 0.11) × 10(exp -10)cu cm/ molecule/s and the reactive rate coefficient, i.e., R-316c loss, was measured to be (1.36 +/- 0.20) × 10(exp -10)cu cm/molecule/s corresponding to a approx. 88% reactive yield. Rate coefficient upper-limits for the OH and O3 reaction with R-316c were determined to be <2.3 × 10(exp -17) and <2.0 × 10(exp -22)cu cm/molecule/s, respectively, at 296 K. The quoted uncertainty limits are 2(sigma) and include estimated systematic errors. Local and global annually averaged lifetimes for the (E)- and (Z)-R-316c isomers were calculated using a 2-D atmospheric model to be 74.6 +/- 3 and 114.1 +/-10 years, respectively, where the estimated uncertainties are due solely to the uncertainty in the UV absorption spectra. Stratospheric photolysis is the predominant atmospheric loss process for both isomers with the O(1D) reaction making a minor, approx. 2% for the (E) isomer and 7% for the (Z) isomer, contribution to the total atmospheric loss. Ozone depletion potentials for (E)- and (Z)-R-316c were calculated using the 2-D model to be 0.46 and 0.54, respectively. Infrared absorption spectra for (E)- and (Z)-R-316c were measured at 296 K and used to estimate their radiative efficiencies (REs) and GWPs; 100-year time-horizon GWPs of 4160 and 5400 were obtained for (E)- and (Z)-R-316c, respectively. Both isomers of R-316c are shown in this work to be long-lived ozone depleting substances and potent greenhouse gases.

    15. Expression of genes for AhR and Nrf2 signal pathways in the retina of OXYS rats during the development of retinopathy and melatonin-induced changes in this process.

      PubMed

      Perepechaeva, M L; Stefanova, N A; Grishanova, A Yu

      2014-08-01

      Modulation of oxidative stress is one of the experimental approaches to the therapy of age-related macular degeneration. Melatonin holds much promise in this respect. It was hypothesized that the efficiency of melatonin in age-related macular degeneration is associated with its ability to modulate gene expression for the AhR and Nrf2 signal pathways. Experiments were performed on premature aging OXYS rats, which serve as a reliable model of age-related macular degeneration in humans. We studied the effect of melatonin on gene mRNA for the AhR and Nrf2 signal pathways. Melatonin was shown to decrease the level of mRNA for AhR-dependent genes of CYP1A2 and CYP1B1 cytochromes in the retina, but had no effect on the content of mRNA for Nrf2-dependent genes in OXYS rats. PMID:25110076

    16. R.E. Burger Plant, Ohio

      SciTech Connect

      Peltier, R.

      2007-10-15

      First Energy's R.E. Burger Plant at Shadyside, OH has hosted a number of R & D projects over the years, but none as large as the demonstration of Powerspan's 30-MW Electro-Catalytic Oxidation (ECO) multipollutant removal process a few years ago. Credit Powerspan for scaling up the demo unit and for adding CO{sub 2} as a target of a new pilot process called ECO{sub 2}.

    17. Viscosity of gaseous R404A, R407C, R410A, and R507

      SciTech Connect

      Nabizadeh, H.; Mayinger, F.

      1999-05-01

      This paper presents new measurements of the viscosity of gaseous R404A (52 wt% R143a, 44 wt% R125, 4 wt% R134a), R407C (23 wt% R32, 25 wt% R125, 52 wt% R143a), R410A (50 wt% R32, 50 wt% R125), and R507 (50 wt% R143a, 50 wt% R125). These mixtures are recommended as substitutes for the refrigerants R22, R502, and R13B1. Measurements were carried out in an oscillating-disk viscometer. The obtained values of the viscosity are relative to the viscosity of nitrogen. The experiments were performed at atmospheric pressure over the temperature range 297 to 403 K and near the saturation line up to pressures of 0.6 P{sub crit}. The estimated uncertainty of the reported viscosities are {+-}0.5% for the viscosities at atmospheric pressure and {+-}15 along the saturation line, being limited by the accuracy of the available vapor pressure and density data. The experimental viscosities at atmospheric pressure are employed to determine the intermolecular potential parameters, {sigma} and {epsilon}, which provide the optimum representation of the data with the aid of the extended law of corresponding states developed by Kestin et al. A comparison of the experimental viscosity data with the values calculated by REFPROP, both at atmospheric pressure and along the saturation line, is presented.

    18. Arsenite evokes IL-6 secretion, autocrine regulation of STAT3 signaling, and miR-21 expression, processes involved in the EMT and malignant transformation of human bronchial epithelial cells

      SciTech Connect

      Luo, Fei; Xu, Yuan; Ling, Min; Zhao, Yue; Xu, Wenchao; Liang, Xiao; Jiang, Rongrong; Wang, Bairu; Bian, Qian; Liu, Qizhan

      2013-11-15

      Arsenite is an established human carcinogen, and arsenite-induced inflammation contributes to malignant transformation of cells, but the molecular mechanisms by which cancers are produced remain to be established. The present results showed that, evoked by arsenite, secretion of interleukin-6 (IL-6), a pro-inflammatory cytokine, led to the activation of STAT3, a transcription activator, and to increased levels of a microRNA, miR-21. Blocking IL-6 with anti-IL-6 antibody and inhibiting STAT3 activation reduced miR-21 expression. For human bronchial epithelial cells, cultured in the presence of anti-IL-6 antibody for 3 days, the arsenite-induced EMT and malignant transformation were reversed. Thus, IL-6, acting on STAT3 signaling, which up-regulates miR-21in an autocrine manner, contributes to the EMT induced by arsenite. These data define a link from inflammation to EMT in the arsenite-induced malignant transformation of HBE cells. This link, mediated through miRNAs, establishes a mechanism for arsenite-induced lung carcinogenesis. - Highlights: • Arsenite evokes IL-6 secretion. • IL-6 autocrine mediates STAT3 signaling and up-regulates miR-21expression. • Inflammation is involved in arsenite-induced EMT.

    19. R u t c o r R e p o r t

      E-print Network

      R u t c o r Research R e p o r t RUTCOR ffl Rutgers Center for Operations Research ffl Rutgers­445­5472 Email: rrr@rutcor.rutgers.edu http://rutcor.rutgers.edu/ rrr Phylogeny Numbers Fred S. Roberts a Li Phylogeny Numbers Fred S. Roberts Li Sheng Abstract. Motivated by problems of phylogenetic tree

    20. R u t c o r R e p o r t

      E-print Network

      of the methods used to generate such numbers are deterministic, i.e. the numbers are only pseudoR u t c o r Research R e p o r t RUTCOR ffl Rutgers Center for Operations Research ffl Rutgers­932­5472 Email: rrr@rutcor.rutgers.edu Quality Evaluation of Random Numbers Generated by Chaotic Circuits

    1. R E S E A R C H A R T I C L E Arbuscular mycorrhizal symbiosis can counterbalance the negative

      E-print Network

      Thioulouse, Jean

      R E S E A R C H A R T I C L E Arbuscular mycorrhizal symbiosis can counterbalance the negative in-6941.2007.00363.x Editor: Karl Ritz Keywords AM symbiosis; plant diversity; catabolic diversity; Eucalyptus. These results highlight the role of AM symbiosis in the processes involved in soil bio-functioning and plant

    2. Test Review: Wagner, R. K., Torgesen, J. K., Rashotte, C. A., & Pearson, N. A., "Comprehensive Test of Phonological Processing-2nd Ed. (CTOPP-2)." Austin, Texas: Pro-Ed

      ERIC Educational Resources Information Center

      Dickens, Rachel H.; Meisinger, Elizabeth B.; Tarar, Jessica M.

      2015-01-01

      The Comprehensive Test of Phonological Processing-Second Edition (CTOPP-2; Wagner, Torgesen, Rashotte, & Pearson, 2013) is a norm-referenced test that measures phonological processing skills related to reading for individuals aged 4 to 24. According to its authors, the CTOPP-2 may be used to identify individuals who are markedly below their…

    3. The R Book The R Book

      E-print Network

      Harms, Kyle E.

      in a variety of electronic formats. Some content that appears in print may not be available in electronic books#12;The R Book #12;The R Book Michael J. Crawley Imperial College London at Silwood Park, UK #12 Telephone +44 1243 779777 Email (for orders and customer service enquiries): cs-books@wiley.co.uk Visit our

    4. Richard B. Standiford Dean R. Donaldson

      E-print Network

      Trees as energy crops Richard B. Standiford Dean R. Donaldson s i n c e the 1973 Arab oil embargo alternative energy sources. Thereis much interestin silviculturalbiomass crops as renewable energy sources for direct process heat, cogeneration (production of electricityand process steam in tandem), and alcohol

    5. An R Package Conculsions/Future

      E-print Network

      Diggle, Peter J.

      Processes #12;Motivation Methods An R Package Examples Conculsions/Future Primary Biliary Cirrhosis in Newcastle-Upon-Tyne Primary Biliary Cirrhosis in Newcastle-Upon-Tyne (Aggregated) Gastrointestinal Disease Surveillance Bovine Tuberculosis in Cornwall Spatial Point Process Data · Primary biliary cirrhosis

    6. R. Khn R. Menzel W. Menzel U. Ratsch M. M. Richter I.-O. Stamatescu (Eds.)

      E-print Network

      Menzel, Randolf - Institut für Biologie

      R. Kühn R. Menzel W. Menzel U. Ratsch M. M. Richter I.-O. Stamatescu (Eds.) Springer Adaptivity the destructive forces of entropy on both slow and fast time scales. Evolution is a process that keeps-specific phylogenetic memory. Organisms also collect and store individual memory on a fast time scale through learning

    7. The standard of neutrality: still flapping in the breeze? S. R. PROULX* & F. R. ADLER

      E-print Network

      Adler, Fred

      REVIEW The standard of neutrality: still flapping in the breeze? S. R. PROULX* & F. R. ADLER: fixation probability; natural selection; neutral process; population genetics; theoretical model. Abstract Neutrality plays an important role as a null model in evolutionary biology. Recent theoretical advances

    8. The Ratio R{sub dp} of the quasielastic nd {yields} p(nn) to the elastic np {yields} pn charge-exchange-process yields at the proton emitting angle {theta}{sub p,lab} = 0 deg. over 0.55-2.0 GeV neutron-beam energy region. Comparison of the results with the model-dependent calculations

      SciTech Connect

      Sharov, V. I. Morozov, A. A.; Shindin, R. A.; Chernykh, E. V.; Nomofilov, A. A.; Strunov, L. N.

      2009-06-15

      Our new experimental results (see, e.g., Preprint JINR no. E1-2008-61 (Dubna, 2008)) on ratio R{sub dp} of the quasielastic charge-exchange yield at the proton emitting angle {theta}{sub p,lab} = 0 deg. for the nd {yields} p(nn) reaction to the elastic np {yields} pn charge-exchange yield were presented. The measurements were carried out at the Nuclotron of the Veksler and Baldin Laboratory of High Energies of the JINR (Dubna) at the neutron-beam kinetic energies of 0.55, 0.8, 1.0, 1.2, 1.4, 1.8, and 2.0 GeV. In this paper the comparison of the experimental R{sub dp} data with the obtained R{sub dp} calculations within the impulse approximation by using the invariant-amplitude sets from the GW/VPI phase-shift analysis is made. The R{sub dp} values calculated using the set of invariant amplitude data for the elastic np {yields} pn charge exchange at {theta}{sub p,CM} = 0 deg., agree with the experimental data. This confirmed the nd {yields} p(nn) process yield at {theta}{sub p,CM} = 0 deg. is caused by the contribution of the spin-dependent part of the elastic np {yields} pn charge-exchange reaction. Thus, it has been shown that the obtained experimental R{sub dp} results can be used for the Delta-Sigma experimental program to reduce the total ambiguity in the extraction of the amplitude real parts.

    9. R u t c o r R e p o r t

      E-print Network

      bounds for quadratic 0 1 minimization Endre Boros a Peter L. Hammer a R. Sun b Gabriel Tavares a RRR 7 minimization Endre Boros Peter L. Hammer R. Sun Gabriel Tavares Abstract. The \\roof dual" of an unconstrained

    10. R u t c o r R e p o r t

      E-print Network

      R u t c o r Research R e p o r t RUTCOR Rutgers Center for Operations Research Rutgers University, 640 Bartholomew Road, Piscataway, NJ 08854­8003, sfoldes@rutcor.rutgers.edu #12; Rutcor Research, then sin 6 APB sin 6 APC \\Delta sin 6 BPC sin 6 BPA \\Delta sin 6 CPA sin 6 CPB = 1 #12; Page 2 RRR 9­98 AM

    11. r-"! J'~''' '''; -+'' ("'tt~-+--

      E-print Network

      ~l':l asse:.:tion t hat. tl:e r:'.embe rs of t he niss i o::!. consj.do r thai::.' op;o::'tuni ty to r8:'lC188test producti on cons i s t ertt wi t h cOT'.t i nued ma'\\.im.um annual yi eld . T! ' r; :~ 21

    12. Publications Vaughan R. Pratt

      E-print Network

      Pratt, Vaughan

      /or Postscript by browsing the URL http://boole.stanford.edu/pub/ABSTRACTS Pratt, V.R., "Transition. Pratt, V.R., "Comonoids in chu: A large cartesian closed sibling of topological spaces", Proc. Workshop on Coalgebraic Methods in Cs (CMCS'03), Elsevier ENTCS 82:1, 1-12, July 2003. Pratt, V.R., "Chu spaces

    13. Factor Analysis Using "R"

      ERIC Educational Resources Information Center

      Beaujean, A. Alexander

      2013-01-01

      "R" (R Development Core Team, 2011) is a very powerful tool to analyze data, that is gaining in popularity due to its costs (its free) and flexibility (its open-source). This article gives a general introduction to using "R" (i.e., loading the program, using functions, importing data). Then, using data from Canivez, Konold, Collins, and Wilson…

    14. Task 21 - Evaluation of Artificial Freeze Crystallization and Natural Freeze-Thaw Processes for the Treatment of Contaminated Groundwater at the Strachan Gas Plant in Alberta, Canada - Sour Gas Remediation Technology R{ampersand}D

      SciTech Connect

      1997-03-01

      During the period from 1993 to 1996, a long-term program was initiated to conduct remediation research at the Strachan Gas Plant in Alberta, Canada. As part of this research program, optimization of the existing pump-and-treat (P{ampersand}T) facility was of interest. The cost-effective treatment of contaminated groundwater produced from the P{ampersand}T system was complicated by several factors, including: (1) increased cost and reduced effectiveness of most water treatment processes because of the cold temperatures and severe winter conditions prevalent in Alberta, (2) interference caused by the mixture of inorganic and organic contaminants found in the groundwater that can reduce the effectiveness of many water treatment processes, and (3) pretreatment to prevent scaling in existing treatment process unit operations caused by the iron, manganese, and hardness of the contaminated groundwater.

    15. DNA Microarrays An R Tutorial

      E-print Network

      Qiu, Weigang

      DNA Microarrays An R Tutorial Gene Expression Analysis & R Tutorial Weigang Qiu Department Expression Analysis & R Tutorial #12;DNA Microarrays An R Tutorial Outline 1 DNA Microarrays 2 An R Tutorial Weigang Qiu Gene Expression Analysis & R Tutorial #12;DNA Microarrays An R Tutorial Functional Genomics

    16. 77 FR 36907 - Establishment of Restricted Areas R-5402, R-5403A, R-5403B, R-5403C, R-5403D, R-5403E, and R...

      Federal Register 2010, 2011, 2012, 2013, 2014

      2012-06-20

      ...R-5403D, R-5403E, and R-5403F; Devils Lake, ND AGENCY: Federal Aviation Administration...restricted area airspace within the Devils Lake Military Operations Area (MOA), overlying...Grafton Range, in the vicinity of Devils Lake, ND. The new restricted areas...

    17. Phototype plant for Nuclear Process Heat (NPH), reference phase. R and D work on Hydrogenated Coal Gasification (HCG). Further operation of semi-industrial plant for hydrogenated coal gasification

      NASA Astrophysics Data System (ADS)

      Fladerer, R.; Schrader, L.

      1982-07-01

      In view of a scale up, leading to a commercial HCG, futher R and D work was performed on the 100 kg C/hr prototype plant. The inclined tube for feeding coal into the fluidized bed, the raw gas/hydrogenation gas heat exchanger, and the modified hydrogen source were tested. Influence on carbon gasification efficiency of dimension of coal particles, humidity of coal, hydrogen content of gasification gas, introduction place of coal in gasifier, height of fluidized bed, and ash content of coal were studied. The plant was operated for 19,400 hr, of which more than 7400 hr under gasification conditions. Carbon gasification rates up to 82% with methane content up to 48% were obtained.

    18. Monsoons: Processes, predictability, and the prospects for P. J. Webster1, V. O. Magana2, T. N. Palmer3, J. Shukla4, R. A. Tomas1, M. Yanai5, and T. Yasunari6

      E-print Network

      Webster, Peter J.

      Monsoons: Processes, predictability, and the prospects for prediction P. J. Webster1, V. O. Magana2 planetary heat sources and sinks, and interactions between them. The Asian-Australian monsoon system, which timescales is a major focus of GOALS. Empirical seasonal forecasts of the monsoon have been made

    19. Fundamental Plasma Processes in Saturn's Magnetosphere B.H. Mauk, D.C. Hamilton, T.W. Hill, G.B. Hospodarsky, R.E. Johnson, C. Paranicas, E. Roussos,

      E-print Network

      Johnson, Robert E.

      Chapter 11 Fundamental Plasma Processes in Saturn's Magnetosphere B.H. Mauk, D.C. Hamilton, T that control the extensive space environ- ment, or magnetosphere, of Saturn (see Chapter 9, for the global under- standing of the operations of Saturn's magnetosphere and its relationship to those of Earth

    20. A Conceptual Framework & Monitoring System for Rangeland Ecosystem Goods, Services & Processes Adaptive Management Cycle. Adapted from Williams, B. K., R. C. Szaro, and C. D. Shapiro. 2007. Adaptive Management: The U.S.

      E-print Network

      Wyoming, University of

      A Conceptual Framework & Monitoring System for Rangeland Ecosystem Goods, Services & Processes.S. Department of the Interior, Washington, DC Rangeland ecosystem goods are tangible outputs from ecosystems the economic system, they are transported, and usually transformed or combined with other goods and services

    1. Process for functionalizing alkanes

      DOEpatents

      Bergman, Robert G. (Kensington, CA); Janowicz, Andrew H. (Wilmington, DE); Periana, Roy A. (Berkeley, CA)

      1988-01-01

      Process for functionalizing saturated hydrocarbons comprising: (a) reacting said saturated hydrocarbons of the formula: R.sub.1 H wherein H represents a hydrogen atom; and R.sub.1 represents a saturated hydrocarbon radical, with a metal complex of the formula: CpRh[P(R.sub.2).sub.3 ]H.sub.2 wherein Cp represents a cyclopentadienyl or alkylcyclopentadienyl radical; Rh represents a rhodium atom; P represents a phosphorus atom; R.sub.2 represents a hydrocarbon radical; H represents a hydrogen atom, in the presence of ultraviolet radiation to form a hydridoalkyl complex of the formula: CpRh[P(R.sub.2).sub.3 ](R.sub.1)H (b) reacting said hydridoalkyl complex with an organic halogenating agent such as a tetrahalomethane or a haloform of the formulas: CX'X''X'''X'''' or CHX'X''X''' wherein X', X'', X'", X"" represent halogens selected from bromine, iodine or chlorine atom, at a temperature in the range of about -60.degree. to -17.degree. C. to form the corresponding haloalkyl complex of step (a) having the formula: CpRhPMe.sub.3 RX; and, (c) reacting said haloalkyl complex formed in (b) with halogen (X.sub.2) at a temperature in the range of about -60.degree. to 25.degree. C. (i.e., ambient) to form a functional haloalkyl compound.

    2. Process Energy Retrofits 

      E-print Network

      Steinmeyer, D.

      1985-01-01

      point on the curve. The discontinuity or activation energy Is due to the coats.of weatherproofing, etc. Note that for this exlsti" Process Energy Retrofits Dan Steinmeyer Monsanto Co St. Louis, Mo U N C E R E T N A E I R N G T y Y... compared to one built 12 years ago?" Some years ago, three Monsanto energy engi neers constructed separate estimates of how we spent our energy dollars. After some debate and research, ve reached the following consensus: CD WHERE DOES THE ENERGY $ GO...

    3. 75 FR 71532 - Airworthiness Directives; Robinson Helicopter Company (Robinson) Model R22, R22 Alpha, R22 Beta...

      Federal Register 2010, 2011, 2012, 2013, 2014

      2010-11-24

      ...Helicopter Company (Robinson) Model R22, R22 Alpha, R22 Beta, and R22 Mariner Helicopters...directive (AD) for Robinson Model R22, R22 Alpha, R22 Beta, and R22 Mariner helicopters...to require for Robinson Model R22, R22 Alpha, R22 Beta, and R22 Mariner...

    4. 75 FR 41104 - Airworthiness Directives; Robinson Helicopter Company (Robinson) Model R22, R22 Alpha, R22 Beta...

      Federal Register 2010, 2011, 2012, 2013, 2014

      2010-07-15

      ...Helicopter Company (Robinson) Model R22, R22 Alpha, R22 Beta, and R22 Mariner Helicopters...directive (AD) for Robinson Model R22, R22 Alpha, R22 Beta, and R22 Mariner helicopters...adopting a new AD for Robinson Model R22, R22 Alpha, R22 Beta, and R22 Mariner...

    5. Clementine Sensor Processing System

      NASA Technical Reports Server (NTRS)

      Feldstein, A. A.

      1993-01-01

      The design of the DSPSE Satellite Controller (DSC) is baselined as a single-string satellite controller. The DSC performs two main functions: health and maintenance of the spacecraft; and image capture, storage, and playback. The DSC contains two processors: a radiation-hardened Mil-Std-1750, and a commercial R3000. The Mil-Std-1750 processor performs all housekeeping operations, while the R3000 is mainly used to perform the image processing functions associated with the navigation functions, as well as performing various experiments. The DSC also contains a data handling unit (DHU) used to interface to various spacecraft imaging sensors and to capture, compress, and store selected images onto the solid-state data recorder. The development of the DSC evolved from several key requirements; the DSPSE satellite was to do the following: (1) have a radiation-hardened spacecraft control system and be immune to single-event upsets (SEU's); (2) use an R3000-based processor to run the star tracker software that was developed by SDIO (due to schedule and cost constraints, there was no time to port the software to a radiation-hardened processor); and (3) fly a commercial processor to verify its suitability for use in a space environment. In order to enhance the DSC reliability, the system was designed with multiple processing paths. These multiple processing paths provide for greater tolerance to various component failures. The DSC was designed so that all housekeeping processing functions are performed by either the Mil-Std-1750 processor or the R3000 processor. The image capture and storage is performed either by the DHU or the R3000 processor.

    6. Surface configuration in $R + ?^4/R$ gravity

      E-print Network

      Mohsen Fathi; Morteza Mohseni

      2015-10-07

      We investigate the conditions on the additional constant $\\mu$ in the so-called $R+\\mu^4/R$ theory of gravity, due to existence of different kinds of space-like surfaces in both weak field and strong field limits, and their possible correspondence to black hole event horizons. Adopting a Schwarzschild limit, we probe the behaviour of $\\mu$ in different contexts of radial and radial-rotational congruence of null geodesics. We show that these cases serve as correspondents to black hole horizons in some peculiar cases of study.

    7. Surface configuration in R + ?4/R gravity

      NASA Astrophysics Data System (ADS)

      Fathi, Mohsen; Mohseni, Morteza

      2015-09-01

      We investigate the conditions on the additional constant ? in the so-called R + ?4/R theory of gravity, due to existence of different kinds of space-like surfaces in both weak field and strong field limits, and their possible correspondence to black hole event horizons. Adopting a Schwarzschild limit, we probe the behavior of ? in different contexts of radial and radial-rotational congruence of null geodesics. We show that these cases serve as correspondents to black hole horizons in some peculiar cases of study.

    8. Pharmacokinetics and Metabolism of (R,R)-Methoxyfenoterol in Rat

      PubMed Central

      Siluk, Danuta; Mager, Donald E.; Kim, Hee Seung; Wang, Yan; Furimsky, Anna M.; Ta, Amy; Iyer, Lalitha V.; Green, Carol E.; Wainer, Irving W.

      2010-01-01

      (R,R)-Fenoterol (Fen), a ?2-adrenoceptor agonist, is under clinical investigation in the treatment of congestive heart disease. The pharmacokinetics and metabolism of the 4-methoxyphenyl derivative of (R,R)-Fen, (R,R)-MFen, have been determined following intravenous and oral administration to the rat and compared with corresponding results obtained with (R,R)-Fen. Results of the study suggest that (R,R)-MFen can offer pharmacokinetic and metabolic advantages in comparison to an earlier (R,R)-Fen.The oral administration revealed that the net exposure of (R,R)-MFen was about three-fold higher than that of (R,R)-Fen (7.2 versus 2.3 min × nmol ml-1), while intravenous administration proved that the clearance was significantly reduced, 48 versus 146 ml min-1 kg-1, the T1/2 was significantly longer, 152.9 versus 108.9 min and the area under the curve (AUC) was significantly increased, 300 versus 119 min × nmol ml-1.(R,R)-MFen was primarily cleared by glucuronidation associated with significant presystemic glucuronidation of the compound. After intravenous and oral administration of (R,R)-MFen, (R,R)-Fen and (R,R)-Fen-G were detected in the urine samples indicating that (R,R)-MFen was O-demethylated and subsequently conjugated to (R,R)-Fen-G. The total (R,R)-Fen and (R,R)-Fen-G as a percentage of the dose after intravenous administration was 3.6% while after oral administration was 0.3%, indicating that only a small fraction of the drug escaped presystemic glucuronidation and was available for O-demethylation.The glucuronidation pattern was confirmed by the results from in vitro studies where incubation of (R,R)-MFen with rat hepatocytes produced (R,R)-MFen-G, (R,R)-Fen and (R,R)-Fen-G, while incubation with rat intestinal microsomes only resulted in the formation of (R,R)-MFen-G. PMID:20039779

    9. Dynamic Evolution in the Symbiotic R Aquarii

      NASA Technical Reports Server (NTRS)

      DePasquale, J. M.; Nichols, J. S.; Kellogg, E. M.

      2007-01-01

      We report on multiple Chandra observations spanning a period of 5 years as well as a more recent XMM observation of the nearby symbiotic binary R Aqr. Spectral analysis of these four observations reveals considerable variability in hardness ratios and in the strength and ionization levels of emission lines which provides insight into white dwarf accretion processes as well as continuum and line formation mechanisms. Chandra imaging of the central source also shows the formation and evolution of a new south west jet. This growing body of high-resolution X-ray data of R Aqr provides a unique glimpse into white dwarf wind-accretion processes and jet formation.

    10. Studsvik Processing Facility Update

      SciTech Connect

      Mason, J. B.; Oliver, T. W.; Hill, G. M.; Davin, P. F.; Ping, M. R.

      2003-02-25

      Studsvik has completed over four years of operation at its Erwin, TN facility. During this time period Studsvik processed over 3.3 million pounds (1.5 million kgs) of radioactive ion exchange bead resin, powdered filter media, and activated carbon, which comprised a cumulative total activity of 18,852.5 Ci (6.98E+08 MBq). To date, the highest radiation level for an incoming resin container has been 395 R/hr (3.95 Sv/h). The Studsvik Processing Facility (SPF) has the capability to safely and efficiently receive and process a wide variety of solid and liquid Low Level Radioactive Waste (LLRW) streams including: Ion Exchange Resins (IER), activated carbon (charcoal), graphite, oils, solvents, and cleaning solutions with contact radiation levels of up to 400 R/hr (4.0 Sv/h). The licensed and heavily shielded SPF can receive and process liquid and solid LLRWs with high water and/or organic content. This paper provides an overview of the last four years of commercial operations processing radioactive LLRW from commercial nuclear power plants. Process improvements and lessons learned will be discussed.

    11. Problem Tools The censored process Results Censored stable processes

      E-print Network

      -Carlos Pardo2 Alex Watson1 1 Unversity of Bath, UK. 2 CIMAT, Mexico. #12;Problem Tools The censored process The censored process Results Lamperti transform (X, Px )x>0 pssMp Xt = exp(S(t)), S a random time-change (, Py )yR killed L´evy s = log(XT(s)), T a random time-change #12;Problem Tools The censored process

    12. miR-25 and miR-92a regulate insulin I biosynthesis in rats.

      PubMed

      Setyowati Karolina, Dwi; Sepramaniam, Sugunavathi; Tan, Hui Zhing; Armugam, Arunmozhiarasi; Jeyaseelan, Kandiah

      2013-08-01

      The 3' UTR of insulin has been identified as a critical region that confers mRNA stability, which is crucial for promoting transcription in response to glucose challenge. miRNAs are endogenously encoded non-coding RNAs that function as regulators of gene expression. This regulatory function is generally mediated by complementary binding to the 3'UTR of its mRNA targets that affects subsequent translational process. Genes involved in the regulation of glucose homeostasis, particularly in insulin production, have been found as targets of several miRNAs. Yet, no direct miRNA-based regulators of insulin biosynthesis have been identified. In this study, identification of possible miRNA-based regulators of insulin production is explored. Members of a miRNA family, miR-25 and miR-92a, are found as direct modulators of insulin expression. Overexpression of miR-25 or miR-92a reduced insulin expression while inhibition of miR-25 and miR-92a expression using corresponding antagomiRs promoted insulin expression and ultimately enhanced glucose-induced insulin secretion. Furthermore, suppression of insulin secretion by pre miR-9 could be attenuated by treatment with anti-miR-25 or miR-92a. Interestingly, we found the binding site of miR-25 and miR-92a to overlap with that of PTBP1, an important RNA binding molecule that stabilizes insulin mRNA for translation. Despite the increase in PTBP1 protein in the pancreas of diabetic rats, we observed insulin expression to be reduced alongside upregulation of miR-25 and miR-92a, suggesting an intricate regulation of insulin (bio)synthesis at its mRNA level. PMID:24084692

    13. F(R) supergravity

      E-print Network

      Sergei Ketov

      2009-10-07

      We review the F(R) supergravity recently proposed in Phys. Lett. B674 (2009) 59 and Class. Quantum Grav. 26 (2009) 135006. Our construction supersymmetrizes popular f(R) theories of modified gravity in four spacetime dimensions. We use curved superspace of N=1 Poincar'e supergravity in its minimal (2nd order) formulation so that our F(R) supergravity action is manifestly invariant under local N=1 supersymmetry. We prove that the F(R) supergravity is classically equivalent to the standard N=1 Poincar'e supergravity (minimally) coupled to a dynamical chiral superfield, via a Legendre-Weyl transform in superspace. A K"ahler potential, a superpotential and a scalar potential of the chiral superfield are governed by a single holomorphic function. We find the conditions of vanishing cosmological constant without fine-tuning, which define a no-scale F(R) supergravity.

    14. Meat Processing.

      ERIC Educational Resources Information Center

      Legacy, Jim; And Others

      This publication provides an introduction to meat processing for adult students in vocational and technical education programs. Organized in four chapters, the booklet provides a brief overview of the meat processing industry and the techniques of meat processing and butchering. The first chapter introduces the meat processing industry and…

    15. INSTALLING R and R Studio R and R Studio are separate packages. You will need to install R first.

      E-print Network

      Utts, Jessica

      ) and follow directions. If Windows, click on "base" and then on Download R 3.2.2 for Windows. (Note that 3 be expected to know how to use it. These instructions should work for Windows and MAC users for installing R on "download R." Find a site of your choice. (The ones at Berkeley and UCLA are closest to us, but you can use

    16. Hydrological analysis in R: Topmodel and beyond

      NASA Astrophysics Data System (ADS)

      Buytaert, W.; Reusser, D.

      2011-12-01

      R is quickly gaining popularity in the hydrological sciences community. The wide range of statistical and mathematical functionality makes it an excellent tool for data analysis, modelling and uncertainty analysis. Topmodel was one of the first hydrological models being implemented as an R package and distributed through R's own distribution network CRAN. This facilitated pre- and postprocessing of data such as parameter sampling, calculation of prediction bounds, and advanced visualisation. However, apart from these basic functionalities, the package did not use many of the more advanced features of the R environment, especially from R's object oriented functionality. With R's increasing expansion in arenas such as high performance computing, big data analysis, and cloud services, we revisit the topmodel package, and use it as an example of how to build and deploy the next generation of hydrological models. R provides a convenient environment and attractive features to build and couple hydrological - and in extension other environmental - models, to develop flexible and effective data assimilation strategies, and to take the model beyond the individual computer by linking into cloud services for both data provision and computing. However, in order to maximise the benefit of these approaches, it will be necessary to adopt standards and ontologies for model interaction and information exchange. Some of those are currently being developed, such as the OGC web processing standards, while other will need to be developed.

    17. The r-Java 2.0 code: nuclear physics

      NASA Astrophysics Data System (ADS)

      Kostka, M.; Koning, N.; Shand, Z.; Ouyed, R.; Jaikumar, P.

      2014-08-01

      Aims: We present r-Java 2.0, a nucleosynthesis code for open use that performs r-process calculations, along with a suite of other analysis tools. Methods: Equipped with a straightforward graphical user interface, r-Java 2.0 is capable of simulating nuclear statistical equilibrium (NSE), calculating r-process abundances for a wide range of input parameters and astrophysical environments, computing the mass fragmentation from neutron-induced fission and studying individual nucleosynthesis processes. Results: In this paper we discuss enhancements to this version of r-Java, especially the ability to solve the full reaction network. The sophisticated fission methodology incorporated in r-Java 2.0 that includes three fission channels (beta-delayed, neutron-induced, and spontaneous fission), along with computation of the mass fragmentation, is compared to the upper limit on mass fission approximation. The effects of including beta-delayed neutron emission on r-process yield is studied. The role of Coulomb interactions in NSE abundances is shown to be significant, supporting previous findings. A comparative analysis was undertaken during the development of r-Java 2.0 whereby we reproduced the results found in the literature from three other r-process codes. This code is capable of simulating the physical environment of the high-entropy wind around a proto-neutron star, the ejecta from a neutron star merger, or the relativistic ejecta from a quark nova. Likewise the users of r-Java 2.0 are given the freedom to define a custom environment. This software provides a platform for comparing proposed r-process sites.

    18. Steven R. Dunbar Department of Mathematics

      E-print Network

      Dunbar, Steve

      called local limit theorems. This is illustrated in Figure 1 In a way, Pascal laid the foundation Theory and Stochastic Processes Steven R. Dunbar Local Limit Theorems Rating Mathematicians Only of the Local Limit Theorem. Vocabulary 1. A local limit theorem describes how the probability mass function

    19. Federal R & D Policies Supporting Educational Technology.

      ERIC Educational Resources Information Center

      Blaschke, Charles; And Others

      1989-01-01

      Summarizes factors contributing to successful federal research and development (R&D) funding for educational technology, and provides policy recommendations based on these findings. Topics discussed include the role of industry; public policy issues; legislative initiatives; executive branch administration; staff continuity; procurement process;…

    20. R.E. Wright 

      E-print Network

      Unknown

      2011-08-17

      stream_source_info Elizabeth R. Wright.pdf.txt stream_content_type text/plain stream_size 12230 Content-Encoding ISO-8859-1 stream_name Elizabeth R. Wright.pdf.txt Content-Type text/plain; charset=ISO-8859-1 42... Armas Wilson, and Isabel Lozano Renieblas when seeking to understand The Labors of Persiles and Sigismunda. Charles Fantazzi. A Companion to Juan Luis Vives. Leiden and Boston: Brill, 2008. viii + 430 pp. $185.00. Review by elizabeth r. wright...

    1. Advanced R Programming for Bioinformatics

      E-print Network

      Rice, Ken

      Prof Lumley · Prof, University of Auckland · R Core developer · Genetic/Genomic research Biostat · Not an authoR, but a useR (and a teacheR) · Genetic/Genomic research in Cardiovascular.g. missing commas and }'s ) · How to manipulate basic data structures in R; in particular vectors and data

    2. Transparent runtime parallelization of the R scripting language

      SciTech Connect

      Yoginath, Srikanth B

      2011-01-01

      Scripting languages such as R and Matlab are widely used in scientific data processing. As the data volume and the complexity of analysis tasks both grow, sequential data processing using these tools often becomes the bottleneck in scientific workflows. We describe pR, a runtime framework for automatic and transparent parallelization of the popular R language used in statistical computing. Recognizing scripting languages interpreted nature and data analysis codes use pattern, we propose several novel techniques: (1) applying parallelizing compiler technology to runtime, whole-program dependence analysis of scripting languages, (2) incremental code analysis assisted with evaluation results, and (3) runtime parallelization of file accesses. Our framework does not require any modification to either the source code or the underlying R implementation. Experimental results demonstrate that pR can exploit both task and data parallelism transparently and overall has better performance as well as scalability compared to an existing parallel R package that requires code modification.

    3. R Tricks for Kids

      ERIC Educational Resources Information Center

      Braun, W. John; White, Bethany J. G.; Craig, Gavin

      2014-01-01

      Real-world phenomena simulation models, which can be used to engage middle-school students with probability, are described. Links to R instructional material and easy-to-use code are provided to facilitate implementation in the classroom.

    4. R u t c o r R e p o r t

      E-print Network

      and their mathematical properties are explored. #12;Page 2 RRR 34-2007 1 Introduction Consider n assets with random) is a fixed probability chosen by ourselves. If R1, . . . , Rn have a normal joint distribution, then

    5. R u t c o r R e p o r t

      E-print Network

      of a set of vectors and the conic hull of a set of directions in Rn : P = conv{v1, . . . , vr} + cone{d1, . . . , ds}, (2) where V(P) = {v1, . . . , vr} Rn is the set of vertices or extreme points of P, D(P) = {d1, . . . , ds} Rn is the set of extreme directions of P, and conv{v1, . . . , vr} = { r i=1 ivi : r i=1 i = 1

    6. Expression Change of miR-214 and miR-135 during Muscle Differentiation

      PubMed Central

      Honardoost, Maryam; Soleimani, Masoud; Arefian, Ehsan; Sarookhani, Mohammad reza

      2015-01-01

      Objective MicroRNAs (miRNAs) are a class of small non-coding RNAs that play pivotal roles in many biological processes such as regulating skeletal muscle development where alterations in miRNA expression are reported during myogenesis. In this study, we aimed to investigate the impact of predicted miRNAs and their target genes on the myoblast to myocyte differentiation process. Materials and Methods This experimental study was conducted on the C2C12 cell line. Using a bioinformatics approach, miR-214 and miR-135 were selected according to their targets as potential factors in myoblast to myocyte differentiation induced by 3% horse serum. Immunocytochemistry (ICC) was undertaken to confirm the differentiation process and quantitative real-time polymerase chain reaction (PCR) to determine the expression level of miRNAs and their targets. Results During myoblast to myocyte differentiation, miR-214 was significantly down- regulated while miRNA-135, Irs2, Akt2 and Insr were overexpressed during the process. Conclusion miR-214 and miR-135 are potential regulators of myogenesis and are involved in skeletal muscle development through regulating the IRS/PI3K pathway. PMID:26464817

    7. Rolling Deck to Repository (R2R): Fleetwide Standard Underway Data Products

      NASA Astrophysics Data System (ADS)

      Sweeney, A. D.; Clark, P. D.; Miller, S. P.; Stocks, K.; Arko, R. A.; Ferrini, V.

      2009-12-01

      The Rolling Deck to Repository (R2R) project was recently launched with the ambitious goal of documenting “routine underway data” from the US academic research fleet and delivering those data to established national archives. Data distributions will be submitted by 18 operating institutions for 30 vessels, from hundreds of cruises per year. R2R will be responsible for digital data collected with instruments that are part of the ship’s permanent equipment and are routinely operated and recorded by the ship’s technicians. Examples include navigation, multibeam, subbottom, gravimeter, magnetics, ADCP, CTD, meteorology, etc. It is anticipated that most underway data will be promptly and publicly released. However R2R will have the ability to securely embargo any specific datasets identified in advance by the chief scientist, for a proprietary hold period of up to two years as mandated by the NSF 04-004 Division of Ocean Sciences Data and Sample Policy. It is important to note that there are data types that R2R will not address. For example, the chief scientist will continue to be responsible for the documentation and archiving of data from specific instruments brought on board by the scientific party, not part of the ship’s standard equipment. Similarly, data collected with National Facility assets including the National Deep Submergence Facility (NDSF), Ocean Bottom Seismograph Instrument Pool (OBSIP) and the National Marine Seismic Facility (NMSF) will continue to be submitted to the appropriate archiving facility directly by those facilities, rather than through R2R. Soon after the shipboard data is received by R2R, the entire original distribution will be safely stored in a deep archive for long-term preservation, and a cataloging process will be undertaken to assemble data sets for delivery to National Data Centers, as described more fully in the invited presentation by Robert Arko, “Rolling Deck to Repository: Technical Design - Experiences and Lessons.” A suite of R2R standard products will be generated for each cruise including (1) Basic Cruise Metadata, (2) Operations Report, and (3) Quality Controlled Navigational Products. Certified R2R navigation will be created at three levels: NavHiRes at the original raw sample rate (usually one sample per second), Nav1Min at a standard 1-minute time interval, and NavControl at a reduced rate appropriate for graphical representation of a cruise at a global or regional scale. These standard data products will be made available for automatic harvesting on www.rvdata.us by repository and data systems, and for download by individual users.

    8. Hydrocarbon Processing`s petrochemical processes `97

      SciTech Connect

      1997-03-01

      The paper compiles information on numerous petrochemical processes, describing the application, the process, yields, economics, commercial plants, references, and licensor. Petrochemicals which are synthesized include: alkylbenzene, methylamines, ammonia, benzene, bisphenol-A, BTX aromatics, butadiene, butanediol, butyraldehyde, caprolactam, cumene, dimethyl terephthalate, ethanolamines, ethylbenzene, ethylene, ethylene glycols, ethylene oxide, formaldehyde, maleic anhydride, methanol, olefins, paraxylene, phenol, phthalic anhydride, polycaproamide, polyethylene, polyethylene terephthalate, polypropylene, PVC, styrene, terephthalic acid, urea, vinyl chloride, and xylene isomers.

    9. D f ti P iDeformation Processing ME 4210: Manufacturing Processes and Engineering

      E-print Network

      Colton, Jonathan S.

      D f ti P iDeformation Processing ver. 1 ME 4210: Manufacturing Processes and Engineering Prof. J drawingWire drawing · Extrusion R lli· Rolling ME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 2009 2 #12;ForgingForging ME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton

    10. Visualisation of proteomics data using R and Bioconductor

      E-print Network

      Gatto, Laurent; Breckels, Lisa M.; Naake, Thomas; Gibb, Sebastian

      2015-04-08

      data to a broad audience. Here, we provided a short overview of the application of the R software to the visualization of proteomics data. We present a summary of R's plotting systems and how they are used to visualize and understand raw and processed...

    11. r-Java 2.0: the astrophysics

      E-print Network

      Kostka, M; Shand, Z; Ouyed, R; Jaikumar, P

      2014-01-01

      [Context:] This article is the second in a two part series introducing r-Java 2.0, a nucleosynthesis code for open use that performs r-process calculations and provides a suite of other analysis tools. [Aims:] The first paper discussed the nuclear physics inherent to r-Java 2.0 and in this article the astrophysics incorporated into the software will be detailed. [Methods:] R-Java 2.0 allows the user to specify the density and temperature evolution for an r-process simulation. Defining how the physical parameters (temperature and density) evolve can effectively simulate the astrophysical conditions for the r-process. Within r-Java 2.0 the user has the option to select astrophysical environments which have unique sets of input parameters available for the user to adjust. In this work we study three proposed r-process sites; neutrino-driven winds around a proto-neutron star, ejecta from a neutron star merger and ejecta from a quark nova. The underlying physics that define the temperature and density evolution fo...

    12. Signal Processing Institute Swiss Federal Institute of Technology, Lausanne

      E-print Network

      Histace, Aymeric

      1 Signal Processing Institute Swiss Federal Institute of Technology, Lausanne 1 Reconnaissance desProf. Jean--Philippe THIRANPhilippe THIRAN Cours 3: Contours actifs Signal Processing Institute Swiss Federal de ces régions.de ces régions. Contours actifs #12;2 Signal Processing Institute Swiss Federal

    13. INSTITUTE OF PHYSICS PUBLISHING JOURNAL OF PHYSICS D: APPLIED PHYSICS J. Phys. D: Appl. Phys. 39 (2006) R227R244 doi:10.1088/0022-3727/39/14/R01

      E-print Network

      Liu, J. Ping

      2006-01-01

      advanced magnetic materials are reviewed, including soft magnetic materials, spintronic materials, magnetic (2006) R227­R244 doi:10.1088/0022-3727/39/14/R01 TOPICAL REVIEW Rapid thermal processing of magnetic of materials structure via expediting phase transitions and tailoring materials morphology. In this review

    14. The Representational Challenges of Fictional Worlds R. Michael Young

      E-print Network

      Young, R. Michael

      The Representational Challenges of Fictional Worlds R. Michael Young Liquid Narrative Group Department of Computer Science North Carolina State University Raleigh, NC, USA young construction and experience of an illusion (Gerrig, 1993; Johnston and Thomas, 1995). This construction process

    15. Information Commons for Rice (IC4R)

      PubMed Central

      2016-01-01

      Rice is the most important staple food for a large part of the world's human population and also a key model organism for plant research. Here, we present Information Commons for Rice (IC4R; http://ic4r.org), a rice knowledgebase featuring adoption of an extensible and sustainable architecture that integrates multiple omics data through community-contributed modules. Each module is developed and maintained by different committed groups, deals with data collection, processing and visualization, and delivers data on-demand via web services. In the current version, IC4R incorporates a variety of rice data through multiple committed modules, including genome-wide expression profiles derived entirely from RNA-Seq data, resequencing-based genomic variations obtained from re-sequencing data of thousands of rice varieties, plant homologous genes covering multiple diverse plant species, post-translational modifications, rice-related literatures and gene annotations contributed by the rice research community. Unlike extant related databases, IC4R is designed for scalability and sustainability and thus also features collaborative integration of rice data and low costs for database update and maintenance. Future directions of IC4R include incorporation of other omics data and association of multiple omics data with agronomically important traits, dedicating to build IC4R into a valuable knowledgebase for both basic and translational researches in rice. PMID:26519466

    16. Information Commons for Rice (IC4R).

      PubMed

      2016-01-01

      Rice is the most important staple food for a large part of the world's human population and also a key model organism for plant research. Here, we present Information Commons for Rice (IC4R; http://ic4r.org), a rice knowledgebase featuring adoption of an extensible and sustainable architecture that integrates multiple omics data through community-contributed modules. Each module is developed and maintained by different committed groups, deals with data collection, processing and visualization, and delivers data on-demand via web services. In the current version, IC4R incorporates a variety of rice data through multiple committed modules, including genome-wide expression profiles derived entirely from RNA-Seq data, resequencing-based genomic variations obtained from re-sequencing data of thousands of rice varieties, plant homologous genes covering multiple diverse plant species, post-translational modifications, rice-related literatures and gene annotations contributed by the rice research community. Unlike extant related databases, IC4R is designed for scalability and sustainability and thus also features collaborative integration of rice data and low costs for database update and maintenance. Future directions of IC4R include incorporation of other omics data and association of multiple omics data with agronomically important traits, dedicating to build IC4R into a valuable knowledgebase for both basic and translational researches in rice. PMID:26519466

    17. Human miR-1271 is a miR-96 paralog with distinct non-conserved brain expression pattern

      PubMed Central

      Jensen, Kevin P.; Covault, Jonathan

      2011-01-01

      Recent deep-sequencing efforts have identified many novel non-conserved small RNAs that are expressed at low levels in certain mammalian cells. Whether these small RNAs are important for mammalian physiology is debatable, therefore we explored the function of one such RNA, human miR-1271. This small RNA is similar in sequence to miR-96, a highly conserved microRNA that when mutated causes hearing loss in humans and mice. Although the miR-1271 and miR-96 sequences differ slightly, our in vitro assays indicate that they have an identical regulatory activity. We have identified brain-expressed mRNAs from genes including, GPHN, RGS2, HOMER1 and KCC2, which share the same miR-96 and miR-1271 regulatory elements. Interestingly, human miR-1271 is expressed abundantly in brain tissue, where miR-96 is not highly expressed. The rodent miR-1271 precursor contains several sequence differences in the precursor stem, which appear to reduce the efficiency of microRNA processing. Our data indicate that although miR-1271 and miR-96 function identically in vitro, they function to some extent uniquely in vivo. Given the expression patterns and nature of the target genes, miR-1271 may have a significant, although non-conserved, role in regulating aspects of neural development or function in humans. PMID:20864449

    18. In-situ defect detection systems for R2R flexible PV barrier films

      NASA Astrophysics Data System (ADS)

      Gao, F.; Muhamedsalih, H.; Tang, D.; Elrawemi, M.; Blunt, L.; Jiang, X.; Edge, S.; Bird, D.; Hollis, P.

      2015-08-01

      Film processing procedures by means of Roll-to-Roll (R2R) for barrier coatings can often result in PV barrier films being manufactured with significant quantities of defects, which results in lower efficiency and a short life span. In order to improve the process yield and product efficiency, it is desirable to develop an inspection system that can detect transparent barrier film defects in the production line during film processing. Off-line detection of defects in transparent PV barrier films is difficult and time consuming. Consequently, implementing an accurate in-situ defects inspection system in the production environment is even more challenging, since the requirements on positioning, fast measurement, long term stability and robustness against environmental disturbance are demanding. This paper reports on the development and deployment of two in-situ PV barrier films defect detection systems, one based on wavelength scanning interferometry (WSI) and the other on White Light Channeled Spectral Interferometry (WLCSI), and the integration into an R2R film processing line at the Centre for Process Innovation (CPI). The paper outlines the environmental vibration strategy for both systems, and the developed auto-focusing methodology for WSI. The systems have been tested and characterised and initial results compared to laboratory-based instrumentation are presented.

    19. DEMONSTRATION BULLETIN: BIOLOGICAL DENITRIFICATION PROCESS, ECOMAT, INC.

      EPA Science Inventory

      EcoMat, Inc. of Hayward, CA has developed a two-stage ex situ anoxic biofilter biodenitrification process. The process is a fixed film bioremediation, using biocarriers and specific bacteria to treat nitrate-contaminated water. Unique to EcoMat's process is a patented mixed bed r...

    20. DEMONSTRATION BULLETIN: EX-SITU ANAEROBIC BIOREMEDIATION TECHNOLOGY - TNT - J.R. SIMPLOT COMPANY

      EPA Science Inventory

      The J. R. Simplot Ex-Situ Anaerobic Bioremediation System, also known as the J.R. Simplot Anaerobic Biological Remediaton Process (the SABRE™ Process), is a technology designed to destroy nitroaromatic and energetic compounds. The process does not evolve any known toxic intermedi...

    1. Dynamic Processes: Spawn Dynamic Processes

      E-print Network

      Dongarra, Jack

      across complex topologies ­ Interfaces well to many parallel run-time systems #12;Static MPI-1 Job · MPI_COMM_WORL D · Contains 16 processes MPI_COMM_WORLD #12;Static MPI-1 Job · MPI_COMM_WORL D · Contains 16 processes · Can only subset the original MPI_COMM_WORL D ­ No external processes MPI_COMM_WORLD Derived comm

    2. R u t c o r R e p o r t

      E-print Network

      is preform manufacturing. One process to make preforms is called modified chemical vapor deposition (MCVD). In the MCVD process, glass is deposited on the inside of a quartz tube. When the deposition is complete

    3. 76 FR 72869 - Proposed Establishment of Restricted Areas R-5402, R-5403A, R-5403B, R-5403C, R-5403D, R-5403E...

      Federal Register 2010, 2011, 2012, 2013, 2014

      2011-11-28

      ...R-5403D, R-5403E, and R-5403F; Devils Lake, ND AGENCY: Federal Aviation Administration...restricted area airspace within the Devils Lake Military Operations Area (MOA), overlying...Grafton Range, in the vicinity of Devils Lake, ND. The new restricted areas would...

    4. R type anion channel

      PubMed Central

      Diatloff, Eugene; Peyronnet, Rémi; Colcombet, Jean; Thomine, Sébastien; Barbier-Brygoo, Hélène

      2010-01-01

      Plant genomes code for channels involved in the transport of cations, anions and uncharged molecules through membranes. Although the molecular identity of channels for cations and uncharged molecules has progressed rapidly in the recent years, the molecular identity of anion channels has lagged behind. Electrophysiological studies have identified S-type (slow) and R-type (rapid) anion channels. In this brief review, we summarize the proposed functions of the R-type anion channels which, like the S-type, were first characterized by electrophysiology over 20 years ago, but unlike the S-type, have still yet to be cloned. We show that the R-type channel can play multiple roles. PMID:21051946

    5. miR-21 in ischemia/reperfusion injury: a double-edged sword?

      PubMed Central

      Xu, Xialian; Kriegel, Alison J.; Jiao, Xiaoyan; Liu, Hong; Bai, Xiaowen; Olson, Jessica; Liang, Mingyu

      2014-01-01

      MicroRNAs (miRNAs or miRs) are endogenous, small RNA molecules that suppress expression of targeted mRNA. miR-21, one of the most extensively studied miRNAs, is importantly involved in divergent pathophysiological processes relating to ischemia/reperfusion (I/R) injury, such as inflammation and angiogenesis. The role of miR-21 in renal I/R is complex, with both protective and pathological pathways being regulated by miR-21. Preconditioning-induced upregulation of miR-21 contributes to the protection against subsequent renal I/R injury through the targeting of genes such as the proapoptotic gene programmed cell death 4 and interactions between miR-21 and hypoxia-inducible factor. Conversely, long-term elevation of miR-21 may be detrimental to the organ by promoting the development of renal interstitial fibrosis following I/R injury. miR-21 is importantly involved in several pathophysiological processes related to I/R injury including inflammation and angiogenesis as well as the biology of stem cells that could be used to treat I/R injury; however, the effect of miR-21 on these processes in renal I/R injury remains to be studied. PMID:25159851

    6. INSTITUTE OF PHYSICS PUBLISHING JOURNAL OF PHYSICS: CONDENSED MATTER J. Phys.: Condens. Matter 15 (2003) R581R607 PII: S0953-8984(03)33589-1

      E-print Network

      Meller, Amit

      2003-01-01

      processes in biology involve the transport of biopolymers across large channels embedded in the plasma at stacks.iop.org/JPhysCM/15/R581 Abstract The transport of biopolymers through large membrane channels (2003) R581­R607 PII: S0953-8984(03)33589-1 TOPICAL REVIEW Dynamics of polynucleotide transport through

    7. Hydrologic Tests at Characterization Wells R-9i, R-13, R-19, R-22, and R-31

      SciTech Connect

      W.J. Stone; S. McLin

      2003-03-01

      Hydrologic information is essential for environmental efforts at Los Alamos National Laboratory. Testing at new characterization wells being drilled to the regional aquifer (''R wells'') to improve the conceptual hydrogeologic model of the Pajarito Plateau is providing such information. Drilling has been by air-rotary casing-advance or open-hole methods. Most wells are completed with multiple screens. After their construction, wells were rigorously developed by wire-brushing, bailing, followed by surging, swabbing, or jetting, and finally by pumping. These methods are effective based on field-parameter measurements and comparison of results of hydrologic testing at well R-31 before and after complete well development. We conducted field tests on various zones of saturation penetrated by the R wells to collect data needed for determining hydraulic properties. This document provides details of the design and execution of testing as well as an analysis of data for five of the new wells: R-9i, R-13, R-19, R-22, and R-31. One well was evaluated by a pumping test (R-13), another was evaluated by both straddle-packer/injection and pumping tests (R-9i), and the rest were evaluated by injection tests alone (R-19, R-22, R-31). Testing was constrained by the regional setting (complex geology and multiple zones of saturation) and well construction (multiscreen completion and the small diameter of the production casing). Packers are required for testing multiscreen wells. The small diameter of the production casing not only precludes the use of a slugger but also limits the capacity of pumps that can be used in testing, especially for the depths involved in the R wells. For example, pumping at a maximum rate of 19 gallons per minute did not significantly stress the regional aquifer at R-13. Although not slug tests, the injection tests are comparable in several ways, and analysis of data by slugtest methods is appropriate. Despite constraints, the results obtained appear valid based on (1) the care taken during test implementation and data analysis, (2) comparison of results for initial and repeated tests obtained by the same analytical method, (3) comparison of results obtained for a given test by different analytical methods, (4) comparison of results with values determined by geophysical logging in the wells and pumping tests of the same geologic units elsewhere on the plateau, and (5) comparison with hydraulic properties commonly reported for similar geologic materials outside the area. Significant contributions of this report are not only the documentation of test design, implementation, and analysis but also a comprehensive table showing the distribution of hydraulic properties for the saturated geologic units tested beneath the Pajarito Plateau. We also offer several recommendations based on testing to date. Placing screens across the water table and geologic contacts as well as employing oversized filter packs hinders testing and should be avoided. In addition, we recommend that future testing include some alternative designs and methods. Multiple methods and routine repeat testing for a given screened interval would permit comparison of results.

    8. R-values

      SciTech Connect

      Roberts, K

      2009-03-03

      I'll try to keep this short and simple. R{sub LANL} = (beta cpm of X{sub exp} on system 'A')/ (beta cpm of {sup 99}Mo{sub exp} on system 'A')/ (beta cpm of X on system 'A', from thermal on {sup 235}U)/ (beta cpm of {sup 99}Mo on system 'A', from thermal on {sup 235}U). As I understand it, the above equation is the historical (as well as current) way of determining R-values using data from beta counting at LANL. The ratio in the denominator, a little 'r', is the 'baseline' or 'calibration' value for a specific beta detector. Over time, if the detector 'drifts' one would see a variation in this 'r' during a thermal calibration measurement. This baseline is what LANL likes to track to monitor specific detector performance - this is not relevant to LLNL where gamma detection is used for determining R-values. LANL states that uncertainty is only dependent upon the count statistics for the isotopes measured. If one tries to convert this to an atom basis, the uncertainties will increase due to the incorporation of the uncertainties in the nuclear data used to convert the cpm to atoms. LLNL switched to gamma detection methods in the 1970s thus replacing our beta counting effort. The equation below is how we have since determined R-values. The numerator ratios atom values of isotopes that are determined by measuring gamma cpm (usually? using several peaks per isotope) and then converting to particle decay in dpm using detector efficiency for each peak and the appropriate branch ratio for each gamma emission. Isotope decay is then converted to atoms using specific activity, mass or volume?, and Avogadro's number. The denominator is simply the ratio of published, cumulative fission product chain yields for isotopes produced in a thermal irradiation on 235U - values of England & Ryder are used by LLNL for the NTNF program. Uncertainties in LLNL R-values are dependent upon gamma counting statistics as well as the nuclear data for each isotope. R{sub LLNL} = (Atoms of X{sub exp})/(Atoms of {sup 99}Mo{sub exp})/(Cumulative Fission Chain Yield of X, from thermal on {sup 235}U)/(Cumulative Fission Chain Yield of {sup 99}Mo, from thermal on {sup 235}U). The next page tabulates fission chain yields and 'atoms per gram' amounts measured in a recent NTNF Thermal Calibration. The R-values in the table are calculated using the LLNL method of determining R. The measure of success is demonstrated by how close to 1.00 the R-value is when determined during a Thermal Calibration. A value of 1.00 is the desired value. In the example below, only four isotopes lie outside of 1.00 by more than 3 percent. These are the four isotopic measurements that obviously need to be improved.

    9. Kellie R. Aarons Ibrahim Abubakar

      E-print Network

      Frantz, Kyle J.

      Renee P. Chahoy Elizabeth R. Chandler William J. Chandonia Matthew A. Chapman Aaron R. Chartrau Da Chen J. Fidalgo Richard W. Filitor Barrett P. Fischer Tammy L. Fletcher Michael C. Flowe Casey R. Fowler Ashley L. Fowler Rachael A. Fox Danielle R. Francuz Lauren E. Freeman Virginia L. Frye Nicole A

    10. HYDROLOGICAL PROCESSES Hydrol. Process. (2008)

      E-print Network

      Kurapov, Alexander

      2008-01-01

      , University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA 2 geological properties and drainage efficiencies. In the groundwater-dominated watershed, aquifer storage in the groundwater-dominated watershed (r D 0Ð52), but climatic factors override geology in controlling the inter

    11. Characteristics of human voice processing Trevor R. Agus

      E-print Network

      from musical instruments and the singing voice, for which the only cue to recognition was timbre (as distributed across the same range of pitches. Listeners therefore had to use timbre cues to perform the task

    12. CALCIUM TRANSPORT PROCESSES OF LOBSTER HEPATOPANCREATIC MITOCHONDRIA. (R823068)

      EPA Science Inventory

      The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

    13. Links between Join Processing and Convex Geometry Christopher R

      E-print Network

      Thrun, Sebastian

      , and Marx from computer sci- ence [2] and one due to Bollob´as and Thomason from ge- ometry [4, Theorem 2-reduce environment. In EDBT, 2010. [2] Albert Atserias, Martin Grohe, and D´aniel Marx. Size bounds and query plans

    14. r-Process Abundance Universality and Actinide Cosmochronology

      E-print Network

      Kaori Otsuki; Grant J. Mathews; Toshitaka Kajino

      2003-06-12

      We review recent observational and theoretical results concerning the presence of actinide nuclei on the surfaces of old halo stars and their use as an age determinant. We present model calculations which show that the observed universality of abundances for 56 = 75 and possibly Z <= 56 as well. This introduces an uncertainty into the use of the Th/Eu chronometer as a means to estimate the ages of the metal deficient stars. We do find, however, that the U/Th ratio is a robust chronometer. This is because the initial production ratio of U to Th is almost independent of the astrophysical nucleosynthesis environment. The largest remaining uncertainties in the U/Th initial production ratio are due to the input nuclear physics models.

    15. INFORMING THE POLICY PROCESS WITH COGNITIVE MAPPING. (R825791)

      EPA Science Inventory

      The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

    16. Neutrinos, Weak Interactions, and r-process Nucleosynthesis

      E-print Network

      A. B. Balantekin

      2006-08-18

      Two of the key issues in understanding the neutron-to-proton ratio in a core-collapse supernova are discussed. One of these is the behavior of the neutrino-nucleon cross sections as supernova energies. The other issue is the many-body properties of the neutrino gas near the core when both one- and two-body interaction terms are included.

    17. R u t c o r R e p o r t

      E-print Network

      is at a white (black) vertex v, White (Black) selects an outgoing arc (v, u). When the play is at a random r(v, u). The play continues forever, and White aims to maximize (Black aims to minimize) the limiting mean (that is, average) payoff. We prove that this class of games is polynomially equivalent

    18. R u t c o r R e p o r t

      E-print Network

      ) selects an outgoing arc (v, u). When the play is at a random vertex v, a vertex u is picked with the given probability p(v, u). In all cases, Black pays White the value r(v, u). The play continues forever, and White aims to maximize (Black aims to minimize) the limiting mean (that is, average) payoff. It was recently

    19. BIBLIOGRAPHY J. R. Walsh

      E-print Network

      Walsh, Jeremy R.

      overabundance in the OBC type stars. Mon. Not. Roy. Astron. Soc., 204, 129. 17. Walsh, J. R., 1983. The electron of the central binary star in the Red Rectangle. Mon. Not. Roy. Astron. Soc., 205, 53P. 19. Meaburn. J., Walsh, J loss rate of the galactic hypergiant HD152236 ( 1 Scorpii ) from optical and near-infrared observations

    20. Simulation Insights Using "R"

      ERIC Educational Resources Information Center

      Kostadinov, Boyan

      2013-01-01

      This article attempts to introduce the reader to computational thinking and solving problems involving randomness. The main technique being employed is the Monte Carlo method, using the freely available software "R for Statistical Computing." The author illustrates the computer simulation approach by focusing on several problems of…

    1. R0 Cosmology ?

      E-print Network

      Gerald Vones

      2001-05-21

      It is postulated that the action of the FRW-universe is the cosmological term of Einsteins theory (no curvature term - R0 Cosmology). The expansion equation emerging from the embedding of this most simple brane world with variable speed of light is deduced. The universal dimensionless coupling constant of gravity is addressed. Some implications on the deep problems of cosmology are discussed.

    2. R. Burl Yarberry

      ERIC Educational Resources Information Center

      Nishimoto, Warren

      2007-01-01

      R. Burl Yarberry was born in 1920 in Pueblo, Colorado. He attended public schools in Pueblo and graduated from high school in 1938. After a year attending the Colorado School of Mines, he enlisted in the U.S. Marine Corps and served in the Pacific during World War II. Following his discharge, he earned a BA in English from Western State College of…

    3. R u t c o r R e p o r t

      E-print Network

      of a probability distribution is used to derive various equivalent problem formula­ tions. Next we introduce the concept of r­concave discrete probability distributions and analyse its relevance for problems under handle the case of a discrete distribution. In [25] a dual type algorithm for solving problem (1) has

    4. R u t c o r R e p o r t

      E-print Network

      -445-5472 Email: rrr@rutcor.rutgers.edu http://rutcor.rutgers.edu/#24;rrr The structure of strongly C 4 -free well; e-mail: igor@rutcor.rutgers.edu #12; Rutcor Research Report RRR 31-2004, September, 2004 The structure of strongly C 4 -free well-covered graphs J. I. Brown R. J. Nowakowski I. E. Zverovich Abstract

    5. Peat Processing

      NASA Technical Reports Server (NTRS)

      1986-01-01

      Humics, Inc. already had patented their process for separating wet peat into components and processing it when they consulted NERAC regarding possible applications. The NERAC search revealed numerous uses for humic acid extracted from peat. The product improves seed germination, stimulates root development, and improves crop yields. There are also potential applications in sewage disposal and horticultural peat, etc.

    6. Jet activity in the symbiotic variable R Aquarii

      NASA Technical Reports Server (NTRS)

      Michalitsianos, A. G.; Hollis, J. M.; Kafatos, M.

      1986-01-01

      Low-resolution ultraviolet spectra of the R Aquarii jet have been obtained with the International Ultraviolet Explorer (IUE). The most recent IUE observations indicate the ionization state of the jet is increasing. Subarcsecond, Very Large Array observations of R Aquarii have resolved the radio-continuum structure into discrete parcels of emission that are extended and nearly collinear. R Aquarii provides evidence that indicates stellar jet activity is not unique to objects associated with high-energy emission processes alone. Rather, the nature of the aligned radio-optical features that comprise the R Aquarii jet indicate that directional mass expulsion, in the form of discrete-collimated ejecta, probably reflect a general, underlying, physical process associated with a wide variety of peculiar stellar objects. As such, the R Aquarii jet constitutes a prototype for jet activity in composite or peculiar emission stars.

    7. r-Java 2.0: the nuclear physics

      E-print Network

      Kostka, M; Shand, Z; Ouyed, R; Jaikumar, P

      2014-01-01

      [Aims:] We present r-Java 2.0, a nucleosynthesis code for open use that performs r-process calculations as well as a suite of other analysis tools. [Methods:] Equipped with a straightforward graphical user interface, r-Java 2.0 is capable of; simulating nuclear statistical equilibrium (NSE), calculating r-process abundances for a wide range of input parameters and astrophysical environments, computing the mass fragmentation from neutron-induced fission as well as the study of individual nucleosynthesis processes. [Results:] In this paper we discuss enhancements made to this version of r-Java, paramount of which is the ability to solve the full reaction network. The sophisticated fission methodology incorporated into r-Java 2.0 which includes three fission channels (beta-delayed, neutron-induced and spontaneous fission) as well as computation of the mass fragmentation is compared to the upper limit on mass fission approximation. The effects of including beta-delayed neutron emission on r-process yield is studi...

    8. miR-27a and miR-27a* contribute to metastatic properties of osteosarcoma cells

      PubMed Central

      Maximov, Vadim; Galasso, Marco; Khawaled, Saleh; Abou-Sharieha, Samah; Volinia, Stefano; Jones, Kevin B.; Croce, Carlo M.; Aqeilan, Rami I.

      2015-01-01

      Osteosarcoma (OS) is the most common primary malignant bone tumor in adolescents and young adults. The essential mechanisms underlying osteosarcomagenesis and progression continue to be obscure. MicroRNAs (miRNAs) have far-reaching effects on the cellular biology of development and cancer. We recently reported that unique miRNA signatures associate with the pathogenesis and progression of OS. Of particular interest, we found that higher expression of miR-27a is associated with clinical metastatic disease. We report here that overexpression of miR-27a/miR-27a*, a microRNA pair derived from a single precursor, promotes pulmonary OS metastases formation. By contrast, sequestering miR-27a/miR-27a* by sponge technology suppressed OS cells invasion and metastases formation. miR-27a/miR-27a* directly repressed CBFA2T3 expression among other target genes. We demonstrated that CBFA2T3 is downregulated in majority of OS samples and its over expression significantly attenuated OS metastatic process mediated by miR-27a/miR-27a* underscoring CBFA2T3 functions as a tumor suppressor in OS. These findings establish that miR-27a/miR-27a* pair plays a significant role in OS metastasis and proposes it as a potential diagnostic and therapeutic target in managing OS metastases. PMID:25749032

    9. Evolution of the miR-290–295/miR-371–373 Cluster Family Seed Repertoire

      PubMed Central

      Wu, Shuang; Aksoy, Munevver; Shi, Jianting; Houbaviy, Hristo Botev

      2014-01-01

      Expression of the mouse miR-290–295 cluster and its miR-371–373 homolog in human is restricted to early embryos, primordial germ cells, the germ line stem cell compartment of the adult testis and to stem cell lines derived from the early embryonic lineages. Sequencing data suggest considerable seed diversification between the seven homologous pre-miRNAs of miR-290–295 but it is not clear if all of the implied miR-290–295 seeds are also conserved in the human miR-371–373 cluster, which consists of only three homologous pre-miRNAs. By employing miRNA target reporters we show that most, if not all, seeds in miR-290–295 are represented in miR-371–373. In the mouse, pre-miR-290, pre-miR-292 and pre-miR-293 express subsets of the miRNA isoforms processed from the single human pre-miR-371. Comparison of the possible miR-290–295/miR-371–373 seed repertoires in placental mammals suggests a model for the evolution of this miRNA cluster family, which would be otherwise difficult to deduce based solely on pre-miRNA sequence comparisons. The conservation of co-expressed seeds that is characteristic of miR-290–295/miR-371–373 should be taken into account in models of the corresponding miRNA-target interaction networks. PMID:25268927

    10. Assessment of Advanced Coal Gasification Processes

      NASA Technical Reports Server (NTRS)

      McCarthy, John; Ferrall, Joseph; Charng, Thomas; Houseman, John

      1981-01-01

      This report represents a technical assessment of the following advanced coal gasification processes: AVCO High Throughput Gasification (HTG) Process; Bell Single-Stage High Mass Flux (HMF) Process; Cities Service/Rockwell (CS/R) Hydrogasification Process; Exxon Catalytic Coal Gasification (CCG) Process. Each process is evaluated for its potential to produce SNG from a bituminous coal. In addition to identifying the new technology these processes represent, key similarities/differences, strengths/weaknesses, and potential improvements to each process are identified. The AVCO HTG and the Bell HMF gasifiers share similarities with respect to: short residence time (SRT), high throughput rate, slagging and syngas as the initial raw product gas. The CS/R Hydrogasifier is also SRT but is non-slagging and produces a raw gas high in methane content. The Exxon CCG gasifier is a long residence time, catalytic, fluidbed reactor producing all of the raw product methane in the gasifier. The report makes the following assessments: 1) while each process has significant potential as coal gasifiers, the CS/R and Exxon processes are better suited for SNG production; 2) the Exxon process is the closest to a commercial level for near-term SNG production; and 3) the SRT processes require significant development including scale-up and turndown demonstration, char processing and/or utilization demonstration, and reactor control and safety features development.

    11. New opportunities in crystalline silicon R D

      SciTech Connect

      Menna, P. )

      1999-03-01

      To support the expected growth of the silicon solar cell industry, we believe that research and development (R D) activities should be carried out in the following areas: [ital polysilicon feedstock] for the PV industry; [ital thin-layer silicon] deposition methods, and more [ital environmentally benign] cell and module manufacturing processes. For each of these activities, we identify the main issues that needed to be addressed. [copyright] [ital 1999 American Institute of Physics.

    12. Coal liquefaction process streams characterization and evaluation

      SciTech Connect

      Robbins, G.A.; Brandes, S.D.; Winschel, R.A.; Burke, F.P.

      1992-03-01

      CONSOL R D is conducting a three-year program to characterize process and product streams from direct coal liquefaction process development projects. The program objectives are two-fold: (1) to obtain and provide appropriate samples of coal liquids for the evaluation of analytical methodology, and (2) to support ongoing DOE-sponsored coal liquefaction process development efforts. The two broad objectives have considerable overlap and together serve to provide a bridge between process development and analytical chemistry.

    13. Membrane Processes.

      PubMed

      Pellegrin, Marie-Laure; Sadler, Mary E; Greiner, Anthony D; Aguinaldo, Jorge; Min, Kyungnan; Zhang, Kai; Arabi, Sara; Burbano, Marie S; Kent, Fraser; Shoaf, Robert

      2015-10-01

      This review, for literature published in 2014, contains information related to membrane processes for municipal and industrial applications. This review is a subsection of the Treatment Systems section of the annual Water Environment Federation literature review and covers the following topics: pretreatment, membrane bioreactor (MBR) configuration, design, nutrient removal, operation, industrial treatment, fixed film and anaerobic membrane systems, reuse, microconstituents removal, membrane technology advances, membrane fouling, and modeling. Other sub-sections of the Treatment Systems section that might relate to this literature review include: Biological Fixed-Film Systems, Activated Sludge and Other Aerobic Suspended Culture Processes, Anaerobic Processes, Water Reclamation and Reuse. The following sections might also have related information on membrane processes: Industrial Wastes, Hazardous Wastes, and Fate and Effects of Pollutants. PMID:26420079

    14. Transplant Process

      MedlinePLUS

      ... of transplant. Discharge from the hospital Planning to go home The discharge process actually begins weeks before ... you What has to happen before you can go home? For the most part, transplant centers don’ ...

    15. COLLAGEN PROCESSING

      Technology Transfer Automated Retrieval System (TEKTRAN)

      Collagen dispersions, produced from fibrils recovered from milled bovine collagen, have shown promise in environmental remediation in applications as settling aids, filtration aids, fractionation media, oil drop stabilizers, and water purification aids. Macroporous structures, processed by controll...

    16. Experimental Evidence for Anomalous Scale Dependent Cascading Process in Turbulent

      E-print Network

      Roux, Stephane

      CASE STUDY Experimental Evidence for Anomalous Scale Dependent Cascading Process in Turbulent of the velocity increment pdf from Gaussian at large scales to more intermittent profiles with stretched using a kernel G: Pl v Gll ln r 1 r2 Pl v r dr. (2) Most of the well-known cascade models can

    17. Self-Assembling Process for Fabricating Tailored Thin Films

      SciTech Connect

      2008-07-31

      A simple, economical nanotechnology coating process that enables the development of nanoparticle thin films with architectures and properties unattainable by any other processing method. 2007 R&D 100 winner (SAND2007-1878P)

    18. Self-Assembling Process for Fabricating Tailored Thin Films

      ScienceCinema

      None

      2010-01-08

      A simple, economical nanotechnology coating process that enables the development of nanoparticle thin films with architectures and properties unattainable by any other processing method. 2007 R&D 100 winner (SAND2007-1878P)

    19. Self-Assembling Process for Fabricating Tailored Thin Films

      ScienceCinema

      Sandia

      2009-09-01

      A simple, economical nanotechnology coating process that enables the development of nanoparticle thin films with architectures and properties unattainable by any other processing method. 2007 R&D 100 winner (SAND2007-1878P)

    20. Image Processing Onboard Spacecraft for Autonomous Plume Detection$

      E-print Network

      Schaffer, Steven

      Image Processing Onboard Spacecraft for Autonomous Plume Detection$ David R. Thompson , Melissa's limited cache and bandwidth, and pre- cludes sustained surveys of plume activity. Onboard processing could image sequences onboard to identify plumes, with events triggering preferential storage, prioritized