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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. The r-PROCESS Record in Meteorites

    NASA Astrophysics Data System (ADS)

    Davis, Andrew M.

    2004-09-01

    The r-process record in bulk meteorites and components of primitive meteorites (including refractory inclusions and presolar grains) is reviewed. Small r-process excesses are seen in bulk meteorites and refractory inclusions. Large r-process enhancements have only been observed in presolar diamond. The unique properties and formation conditions of presolar diamond, high purity and high surface-to-volume ratio, may allow it to preserve an r-process signature. It is suggested that the conditions under which r-process matter is ejected from a nascent neutron star dictate that apart from diamonds, strong r-process enhancements are not to be expected in larger presolar grains and other solar system components.

  3. 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.

  4. The R-process and nucleochronology

    NASA Astrophysics Data System (ADS)

    Cowan, John J.; Thielemann, Friedrich-Karl; Truran, James W.

    1991-11-01

    The r-process of nucleosynthesis is the process which is responsible for the synthesis of approximately half of the nuclear species in nature that are more massive than iron. This process of heavy-element synthesis involves the progressive buildup of heavier isotopes via neut ron captures proceeding on neutron-rich isotopes, interspersed by beta decays. Its abudance features clearly reflect nuclear propeties - the maxima are related to the magic neutron numbers N = 50, 82 and 126. It probes our knowledge of the properties of nuclei far from the region of beta stability, even through the position of the neutron drip line. The r-process also forms the important long-lived nuclear chronometers 232Th, 238U and 235U that are utilized for dating the Galaxy. While the astrophysical site foprocess nucleosynthesis is not yet identified, its association with massive stars undergoing type II supernova events is strongly suggested. This can be deduced from the observation that r-process nuclei are already present in the oldest and most metal-deficient stars, which are the tracers of the chemical evolution of the Galaxy. The massive stars that become type II supernovae evolve fastest and contribute their ejecta to the interstellar medium at the earliest beginnings of the chemical evolution of the Galaxy. When utilizing the knowledge of the r-process production ratios of the long-lived chronometer nuclei, their observed ratios in primitive meteorites and our (limited) knowledge of star formation throughout galactic evolution, one can put limits on the duration of galactic nucleosynthesis, the age of the Galaxy and the universe. The latter has a large uncertainty but is comparable with ages estimated from globular clusters and cosmology. This paper will provide a review of the basic physics underlying the r-process, the operation of the mechanisms for r-process nucleosynthesis, the possible astrophysical sites, their time evolution in galactic evolution models, and the inferred

  5. Superheavy elements and r-process

    SciTech Connect

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

    2009-06-15

    The probability for the production of superheavy elements in the astrophysical r-process is discussed. The dependence of the estimated superheavy-element yields on input data is estimated. Preliminary calculations revealed that the superheavy-element yields at the instant of completion of the r-process may be commensurate with the uranium yield, but the former depend strongly on the models used to forecast the properties of beta-delayed, neutron-induced, and spontaneous fission. This study is dedicated to the 80th anniversary of V.S. Imshennik's birth.

  6. Neutron capture in the r-process

    SciTech Connect

    Surman, Rebecca; Mclaughlin, Gail C; Mumpower, Matthew; Hix, William Raphael; Jones, K. L.

    2010-01-01

    Recently we have shown that neutron capture rates on nuclei near stability significantly influence the r-process abundance pattern. We discuss the different mechanisms by which the abundance pattern is sensitive to the capture rates and identify key nuclei whose rates are of particular im- portance. Here we consider nuclei in the A = 130 and A = 80 regions.

  7. 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.

  8. 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.

  9. 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.

  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. 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.

  12. The r-Process Elements: Physics, Origin, and RIA

    NASA Astrophysics Data System (ADS)

    Qian, Yong-Zhong

    2003-10-01

    Approximately half of the heavy elements with A>70 are made via rapid neutron capture, the r-process. The conditions required for this process have been examined in terms of the parameters for adiabatic expansion from high temperature and density. There have been many developments regarding core-collapse supernova and neutron star merger models of the r-process. Meteoritic data and observations of metal-poor stars have demonstrated the diversity of r-process sources. Stellar observations have also found some regularity in r-process abundance patterns and large dispersions in r-process abundances at low metallicities. This talk will summarize the recent results from parametric studies, astrophysical models, and observational studies of the r-process. The interplay between nuclear physics and astrophysics will be emphasized. Possible measurements crucial to r-process studies will be discussed in connection with rare isotope accelerator facilities such as RIA .

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

    SciTech Connect

    Surman, R.; Mumpower, M.; Sinclair, R.; Jones, K. L.; Hix, W. R.; 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.

  14. 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.

  15. MPTinR: analysis of multinomial processing tree models in R.

    PubMed

    Singmann, Henrik; Kellen, David

    2013-06-01

    We introduce MPTinR, a software package developed for the analysis of multinomial processing tree (MPT) models. MPT models represent a prominent class of cognitive measurement models for categorical data with applications in a wide variety of fields. MPTinR is the first software for the analysis of MPT models in the statistical programming language R, providing a modeling framework that is more flexible than standalone software packages. MPTinR also introduces important features such as (1) the ability to calculate the Fisher information approximation measure of model complexity for MPT models, (2) the ability to fit models for categorical data outside the MPT model class, such as signal detection models, (3) a function for model selection across a set of nested and nonnested candidate models (using several model selection indices), and (4) multicore fitting. MPTinR is available from the Comprehensive R Archive Network at http://cran.r-project.org/web/packages/MPTinR/ . PMID:23344733

  16. THE R-PROCESS: Observations, models and unresolved issues

    NASA Astrophysics Data System (ADS)

    Cowan, John

    2002-10-01

    An overview of the the rapid neutron capture process (i.e., the r-process) will be presented. Abundances of these neutron-capture nuclei and elements in solar system material will first be compared with elemental and isotopic abundance patterns in certain galactic halo stars. These comparisons can then be used to identify the types of conditions and to constrain various models for the formation of the r-process nuclei. The models and comparisons will also be discussed in the context of the remaining problems and open questions in the r-process. These include the general lack of nuclear data for the most neutron-rich nuclei and the critical nature of the nuclear mass formulae; differences in the production of the heavier (above barium) and lighter neutron-capture elements; and the uncertainties in identifying the actual astrophysical site for the r-process and the evidence for, and the possible existence of, more than one such site.

  17. 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.

  18. Neutron Capture Rates and r-PROCESS Nucleosynthesis

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    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 β 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.

  19. 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.

  20. Impact of Nuclear Mass Uncertainties on the r Process

    NASA Astrophysics Data System (ADS)

    Martin, D.; Arcones, A.; Nazarewicz, W.; Olsen, E.

    2016-03-01

    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 the 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 the nuclear theory and experiments, when linked to observations, will help in the understanding of astrophysical conditions in extreme r -process sites.

  1. Impact of Nuclear Mass Uncertainties on the r Process.

    PubMed

    Martin, D; Arcones, A; Nazarewicz, W; Olsen, E

    2016-03-25

    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 the 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 the nuclear theory and experiments, when linked to observations, will help in the understanding of astrophysical conditions in extreme r-process sites. PMID:27058066

  2. Monte Carlo calculations for r-process nucleosynthesis

    SciTech Connect

    Mumpower, Matthew Ryan

    2015-11-12

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

  3. On the r-process Enrichment of Dwarf Spheroidal Galaxies

    NASA Astrophysics Data System (ADS)

    Bramante, Joseph; Linden, Tim

    2016-07-01

    Recent observations of Reticulum II have uncovered an overabundance of r-process elements compared to similar ultra-faint dwarf spheroidal galaxies (UFDs). Because the metallicity and star formation history of Reticulum II appear consistent with all known UFDs, the high r-process abundance of Reticulum II suggests enrichment through a single, rare event, such as a double neutron star (NS) merger. However, we note that this scenario is extremely unlikely, as binary stellar evolution models require significant supernova natal kicks to produce NS–NS or NS–black hole (BH) mergers, and these kicks would efficiently remove compact binary systems from the weak gravitational potentials of UFDs. We examine alternative mechanisms for the production of r-process elements in UFDs, including a novel mechanism wherein NSs in regions of high dark matter (DM) density implode after accumulating a BH-forming mass of DM. We find that r-process proto-material ejection by tidal forces, when a single NS implodes into a BH, can occur at a rate matching the r-process abundance of both Reticulum II and the Milky Way. Remarkably, DM models which collapse a single NS in observed UFDs also solve the missing pulsar problem in the Milky Way Galactic Center. We propose tests specific to DM r-process production which may uncover or rule out this model.

  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. Nucleosynthesis of heavy elements in the r-process

    NASA Astrophysics Data System (ADS)

    Panov, I. V.

    2016-03-01

    The current state of the problem of heavy-element production in the astrophysical r-process is surveyed. The nucleosynthesis process in the neutron-star-merger scenario, within which the problem of free-neutron source is solved, is considered most comprehensively. A model that describes well the observed abundances of heavy elements is examined. Theoretical approaches used in this model to calculate a number of features of short-lived neutron-rich nuclei are described. The contributions of various fission processes to the production of heavy elements are assessed. The possibility of superheavy-element production in the r-process is demonstrated.

  6. Quantitative Northern Blot Analysis of Mammalian rRNA Processing.

    PubMed

    Wang, Minshi; Pestov, Dimitri G

    2016-01-01

    Assembly of eukaryotic ribosomes is an elaborate biosynthetic process that begins in the nucleolus and requires hundreds of cellular factors. Analysis of rRNA processing has been instrumental for studying the mechanisms of ribosome biogenesis and effects of stress conditions on the molecular milieu of the nucleolus. Here, we describe the quantitative analysis of the steady-state levels of rRNA precursors, applicable to studies in mammalian cells and other organisms. We include protocols for gel electrophoresis and northern blotting of rRNA precursors using procedures optimized for the large size of these RNAs. We also describe the ratio analysis of multiple precursors, a technique that facilitates the accurate assessment of changes in the efficiency of individual pre-rRNA processing steps. PMID:27576717

  7. Sensitivity studies for the main r process: nuclear masses

    SciTech Connect

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

    2014-04-15

    The site of the rapid neutron capture process (r process) is one of the open challenges in all of physics today. The r process is thought to be responsible for the creation of more than half of all elements beyond iron. The scientific challenges to understanding the origin of the heavy elements beyond iron lie in both the uncertainties associated with astrophysical conditions that are needed to allow an r process to occur and a vast lack of knowledge about the properties of nuclei far from stability. One way is to disentangle the nuclear and astrophysical components of the question. On the nuclear physics side, there is great global competition to access and measure the most exotic nuclei that existing facilities can reach, while simultaneously building new, more powerful accelerators to make even more exotic nuclei. On the astrophysics side, various astrophysical scenarios for the production of the heaviest elements have been proposed but open questions remain. This paper reports on a sensitivity study of the r process to determine the most crucial nuclear masses to measure using an r-process simulation code, several mass models (FRDM, Duflo-Zuker, and HFB-21), and three potential astrophysical scenarios.

  8. Where, oh where has the r-process gone?

    NASA Astrophysics Data System (ADS)

    Qian, Y.-Z.; Wasserburg, G. J.

    2007-04-01

    We present a review of the possible sources for r-process nuclei (r-nuclei). It is known that there is as yet no self-consistent mechanism to provide abundant neutrons for a robust r-process in the neutrino-driven winds from nascent neutron stars. We consider that the heavy r-nuclei with mass numbers A>130 (Ba and above) cannot be produced in the neutrino-driven winds. Nonetheless, the r-process and the neutrino-driven winds may be directly or indirectly related by some unknown additional mechanism, which, for example, could provide ejecta with very short dynamic timescales of ≲0.004s. This undetermined mechanism must supply a neutron source within the same general stellar sites that undergo core collapse to produce the neutron star. Observational data on low-metallicity stars in the Galactic halo show that sites producing the heavy r-nuclei do not produce Fe or any other elements between N and Ge. Insofar as a forming neutron star is key to producing the heavy r-nuclei, then the only possible sources are supernovae resulting from collapse of O Ne Mg cores or accretion-induced collapse of white dwarfs, neither of which produce the elements of the Fe group or those of intermediate mass (above C and N). Observational evidence on s and r-nuclei in low-metallicity stars with high C and N abundances shows that the r-process is also active in binary systems. The nuclei with A˜90 110 produced by charged-particle reactions (CPR) in the neutrino-driven winds are in general present in metal-poor stars with high or low abundances of heavy r-nuclei. The CPR nuclei and the heavy r-nuclei are not strongly coupled. Some metal-poor stars show extremely high enrichments of heavy r-nuclei and have established that the abundance patterns of these nuclei are universally close to the solar abundance pattern of heavy r-nuclei. Using a template star with high enrichments of heavy r-nuclei and another with low enrichments we develop a two-component model based on the abundances of Eu

  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. 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.

  11. 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

  12. 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

  13. r-PROCESS Nucleosynthesis in Proto-Magnetar Winds

    NASA Astrophysics Data System (ADS)

    Thompson, Todd A.

    2004-09-01

    The astrophysical origin of the r-process nuclei is unknown. Because of their association with supernovae and intrinsic neutron-richness, protoneutron star winds are considered as a likely candidate site for production of the r-process nuclei. However, most models of winds from "canonical" neutron stars with mass of 1.4 M⊙ and radius of 10 km fail to generate the heaviest r-process nuclei. In this proceedings we provide a brief review of the protoneutron star wind scenario and discuss the emergence of these outflows in the context of fully dynamical models of successful core-collapse supernovae. That standard models fail motivates an exploration of more extreme neutron star environments. We address some issues surrounding winds from highly magnetic (B0 ≳ 1015 G) protoneutron stars ('proto-magnetars'), including magnetic trapping of wind material and entropy amplification. We further speculate on the role of rapid rotation in this context and the resulting nucleosynthesis.

  14. r-PROCESS Reaction Rates for the Actinides and Beyond

    NASA Astrophysics Data System (ADS)

    Panov, I. V.; Korneev, I. Yu.; Rauscher, T.; Thielemann, F.-K.

    2011-10-01

    We discuss the importance of different fission rates for the formation of heavy and superheavy nuclei in the astrophysical r-process. Neutron-induced reaction rates, including fission and neutron capture, are calculated in the temperature range 108 ≤ T(K) ≤ 1010 within the framework of the statistical model for targets with the atomic number 84 ≤ Z ≤ 118 (from Po to Uuo) from the neutron to the proton drip-line for different mass and fission barrier predictions based on Thomas-Fermi (TF), Extended Thomas-Fermi plus Strutinsky Integral (ETFSI), Finite-Range Droplet Model (FRDM) and Hartree-Fock-Bogolyubov (HFB) approaches. The contribution of spontaneous fission as well as beta-delayed fission to the recycling r-process is discussed. We also discuss the possibility of rate tests, based on mini r-processed yields in nuclear explosions.

  15. Use of the median process of the pygophore in the identification of Rhodnius nasutus, R. neglectus, R. prolixus and R. robustus (Hemiptera: Reduviidae).

    PubMed

    Harry, M

    1993-06-01

    The morphometrics of the median process of the male pygophore of four species of blood-sucking bugs (Rhodnius prolixus, R. robustus, R. nasutus and R. neglectus) were compared using one-way analysis of variance. Although there were no significant differences in the pygophoral patterns within the R. nasutus-R. neglectus or R. prolixus-R. robustus species pairs, there were clear-cut differences between them; the median process of R. nasutus-R. neglectus is stout and subtriangular whereas that of R. prolixus-R. robustus is more narrow and elongated. The basal width of the process, classically used to separate R. robustus from R. prolixus and R. nasutus from R. neglectus, seems to have little taxonomic value. Other characters which have been assumed to be species-specific should be subjected to a similar quantitative analysis. PMID:8257239

  16. 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

  17. Steady flow approximations to the helium r-process

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.; Cowan, J. J.; Klapdor, H. V.; Metzinger, J.; Oda, T.; Truran, J. W.

    1983-01-01

    A steady flow approximation to the r-process is presented and used for numerical experiments with physical quantities to determine the sensitivity of the process to variations in those quantities. The effect of neutron capture cross sections along the capture path and of recently available improved beta decay rates on the r-process are discussed. The peaks in the observed r-process yield curve near mass numbers 80 and 130 are roughly characterized by a neutron number density of 10 to the 20th per cu/cm; the mean beta decay rates are about 10/s, and the freezing time is comparable to or less than 0.1 s. The peak near mass number 195 is roughly characterized by a neutron number density of 10 to the 21st/cm, the mean beta decay rates are about 100/s, and the freezing time is comparable to or less than 0.01 s. The flow path of the steady state r-process is sensitively dependent upon the neutron capture cross sections in the flow network and on the values of the beta decay rates.

  18. Nuclear structure for SNe r- and neutrino processes

    NASA Astrophysics Data System (ADS)

    Suzuki, Toshio

    2014-09-01

    SNe r- and neutrino-processes are investigated based on recent advances in the studies of spin responses in nuclei. New shell-model Hamiltonians, which can well describe spin responses in nuclei with proper tensor components, are used to make accurate evaluations of reaction cross sections and rates in astrophysical processes. Nucleosyntheses in SNe r- and ν -processes as well as rp-processes are discussed with these new reaction rates with improved accuracies. (1) Beta-decay rates for N = 126 isotones are evaluated by shell-model calculations, and new rates are applied to study r-process nucleosynthesis in SNe's around its third peak as well as beyond the peak region up to uranium. (2) ν -processes for light-element synthesis in core-collapse SNe are studied with a new shell-model Hamiltonian in p-shell, SFO. Effects of MSW ν -oscillations on the production yields of 7Li and 11B and sensitivity of the yield ratio on ν -oscillation parameters are discussed. ν -induced reactions on 16O are also studied. (3) A new shell-model Hamiltonian in pf-shell, GXPF1J, is used to evaluate e-capture rates in pf-shell nuclei at stellar environments. New e-capture rates are applied to study nucleosynthesis in type-Ia supernova explosions, rp-process and X-ray bursts.

  19. Global Monte Carlo Calculations for r-process Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Mumpower, Matthew; Surman, Rebecca; Aprahamian, Ani

    2015-10-01

    The rapid neutron capture process is believed to be responsible for the production of approximately half of the heavy elements above iron on the periodic table. Nuclear physics properties (e.g. nuclear masses, neutron capture rates, β-decay rates, and β-delayed neutron emission branching ratios) are critical inputs that go into theoretical calculations of this nucleosynthesis process. We highlight the current capabilities of nuclear models to reproduce the pattern of solar r-process residuals by performing global Monte Carlo variations of the uncertain nuclear physics inputs. We also explore the reduction in uncertainties that may arise from new measurements or improved modeling and discuss the implications for using abundance pattern details to constrain the site of the r process. This work was supported in part by the National Science Foundation through the Joint Institute for Nuclear Astrophysics Grant Numbers PHY0822648 and PHY1419765, and the Department of Energy under Contracts DE-SC0013039 (RS).

  20. 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.

  1. The Impact of Fission on R-Process Calculations

    NASA Astrophysics Data System (ADS)

    Eichler, M.; Arcones, A.; Käppeli, R.; Korobkin, O.; Liebendörfer, M.; Martinez-Pinedo, G.; Panov, I. V.; Rauscher, T.; Rosswog, S.; Thielemann, F.-K.; Winteler, C.

    2016-01-01

    We have performed r-process calculations in neutron star mergers (NSM) and jets of magnetohydrodynamically driven (MHD) supernovae. In these very neutron-rich environments the fission model of heavy nuclei has an impact on the shape of the final abundance distribution and the second r-process peak in particular. We have studied the effect of different fission fragment mass distribution models in calculations of low-Ye ejecta, ranging from a simple parametrization to extensive statistical treatments (ABLA07). The r-process path ends when it reaches an area in the nuclear chart where fission dominates over further neutron captures. The position of this point is determined by the fission barriers and the neutron separation energies of the nuclei involved. As these values both depend on the choice of the nuclear mass model, so does the r-process path. Here we present calculations using the FRDM (Finite Range Droplet Model) and the ETFSI (Extended Thomas Fermi with Strutinsky Integral) mass model with the related TF and ETFSI fission barrier predictions. Utilizing sophisticated fission fragment distribution leads to a highly improved abundance distribution.

  2. 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.

  3. The r-PROCESS in Core-Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Wanajo, Shinya; Kajino, Toshitaka; Mathews, Grant J.; Otsuki, Kaori

    We present calculations of r-process nucleosynthesis in neutrino-driven winds from the nascent neutron stars of core-collapse supernovae. A full dynamical reaction network for both the α-rich freezeout and the subsequent r-process is employed. The physical properties of the neutrino-heated ejecta are deduced from a general relativistic model in which spherical symmetry and steady flow are assumed. Our results suggest that proto-neutron stars with a large compaction ratio provide the most robust physical conditions for the r-process. This is due to the short dynamical timescale of material in the wind. Our results have confirmed that the neutrino-driven wind scenario is still a promising site in which to form the solar r-process abundances. However, our best results seem to imply both a rather soft neutron-star equation of state and a massive proto-neutron star which is difficult to achieve with standard core-collapse models. We propose that the most favorable conditions perhaps require that a massive supernova progenitor forms a massive proto-neutron star by accretion after a failed initial neutrino burst.

  4. Sensitivity to masses in the r-process

    NASA Astrophysics Data System (ADS)

    Brett, Sam; Aprahamian, Ani

    2009-10-01

    The rapid neutron capture process is thought to produce over 50% of the elements beyond iron and still remains, in many ways, a mystery. Questions about the site, conditions and whether it is a single process are outstanding open questions. The process is affected by the astrophysics of the scenario and the nuclear physics of the nuclei involved in the process. Simulations of the r-process require large sets of data such as cross sections, separation energies and decay rates. Clearly, it would be desirable if all of these data sets to be observed and experimentally proven, but since we are looking toward extremely neutron rich nuclei, perilously close to the drip line, we must use many theoretical values. Using an r-process simulation written by Bradley Meyer in 1993, we have been able to see the effects of changing the mass models (and therefore the separation energies) on the final abundances. The input includes the Finite Range Droplet Model, the ETFSI, Duflo-Zucker, and F0 models. By comparing these theoretical models against each other and against known masses, we hope to be able to suggest key regions for further mass measurements.

  5. β-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 β-decay half-lives, low-lying states, β-delayed neutron emissions, isomeric states, and possibly Q{sub β} 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 βγ spectroscopy study using in-flight fission of {sup 238}U-beam will be presented together with our future perspectives.

  6. Predictions for nuclear properties along the r-process path

    SciTech Connect

    Aprahamian, A.

    1987-10-15

    The uniformity of different nuclear regions as a function of the number of valence protons and neutrons (counted from the nearest closed shell) has been exploited for the parameterization of calculations for nuclei far from stability within the IBA model. Predictions are given for low lying levels, E2 transition rates, and binding energies for nuclei in the r-process path in the A = 150 and A = 190 mass regions. 6 refs., 6 figs.

  7. Space - A unique environment for process modeling R&D

    NASA Technical Reports Server (NTRS)

    Overfelt, Tony

    1991-01-01

    Process modeling, the application of advanced computational techniques to simulate real processes as they occur in regular use, e.g., welding, casting and semiconductor crystal growth, is discussed. Using the low-gravity environment of space will accelerate the technical validation of the procedures and enable extremely accurate determinations of the many necessary thermophysical properties. Attention is given to NASA's centers for the commercial development of space; joint ventures of universities, industries, and goverment agencies to study the unique attributes of space that offer potential for applied R&D and eventual commercial exploitation.

  8. r-process enhanched metal-poor stars

    NASA Astrophysics Data System (ADS)

    Cowan, John; Sneden, Christopher; Lawler, James E.; Den Hartog, Elizabeth A.

    Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the earliest generations of stars in the Galaxy - the progenitors of the halo stars - responsible for neutron-capture synthesis of the heavy elements. The large star-to-star scatter observed in the abundances of neutron-capture element/iron ratios at low metallicities - which diminishes with in- creasing metallicity or [Fe/H] - suggests the formation of these heavy elements (presumably from certain types of supernovae) was rare in the early Galaxy. The stellar abundances also indicate a change from the r-process to the slow neutron capture (i.e., s-) process at higher metallicities in the Galaxy and provide insight into Galactic chemical evolution. Finally, the detection of thorium and uranium in halo and globular cluster stars offers an independent age-dating technique that can put lower limits on the age of the Galaxy, and hence the Universe.

  9. 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.

  10. Inhomogeneous chemical evolution of r-process elements

    NASA Astrophysics Data System (ADS)

    Wehmeyer, B.; Pignatari, M.; Thielemann, F.-K.

    2016-06-01

    We report the results of a galactic chemical evolution (GCE) study for r-process- and alpha elements. For this work, we used the inhomogeneous GCE model "ICE", which allows to keep track of the galactic abundances of elements produced by different astrophysical sites. The main input parameters for this study were: a) The Neutron Star Merger (NSM) coalescence time scale, the probability of NSMs, and for the sub-class of "magneto-rotationally driven Supernovae" ("Jet-SNe"), their occurence rate in comparison to "standard" Supernovae (SNe).

  11. 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

  12. 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

  13. 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 τ. We find that the ejecta is lanthanide-free for Ye ≳ 0.22-0.30, depending on s and τ. The heating rate is insensitive to s and τ, 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 τ to estimate whether or not the ejecta is lanthanide-rich.

  14. 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.

  15. r-Java: An r-process Code and Graphical User Interface for Heavy-Element Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Charignon, Camille; Kostka, Mathew; Konin, Nico; Jaikumar, Prashanth; Ouyed, Rachid

    2011-04-01

    We present r-Java, an r-process code for open use, that performs r-process nucleosynthesis calculations. Equipped with a simple graphical user interface, r-Java is capable of carrying out nuclear statistical equilibrium (NSE) as well as static and dynamic r-process calculations for a wide range of input parameters. In this introductory paper, we present the motivation and details behind r-Java, and results from our static and dynamic simulations. Static simulations are explored for a range of neutron irradiation and temperatures. Dynamic simulations are studied with a parameterized expansion formula. Our code generates the resulting abundance pattern based on a general entropy expression that can be applied to degenerate as well as non-degenerate matter, allowing us to track the rapid density and temperature evolution of the ejecta during the initial stages of ejecta expansion. At present, our calculations are limited to the waiting-point approximation.

  16. 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.

  17. Helping science to succeed: improving processes in R&D.

    PubMed

    Sewing, Andreas; Winchester, Toby; Carnell, Pauline; Hampton, David; Keighley, Wilma

    2008-03-01

    Bringing drugs to the market remains a costly and, until now, often unpredictable challenge. Although understanding the underlying science is key to further progress, our imperfect knowledge of disease and complex biological systems leaves excellence in execution as the most tangible lever to sustain our serendipitous approach to drug discovery. The problems encountered in pharmaceutical R&D are not unique, but to learn from other industries it is important to recognise similarity, rather than differences, and to advance industrialisation of R&D beyond technology and automation. Tools like Lean and Six Sigma, already applied to increase business excellence across diverse organisations, can equally be introduced to pharmaceutical R&D and offer the potential to transform operations without large-scale investment. PMID:18342798

  18. 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.

  19. r-Java: an r-process code and graphical user interface for heavy-element nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Charignon, C.; Kostka, M.; Koning, N.; Jaikumar, P.; Ouyed, R.

    2011-07-01

    We present r-Java, an r-process code for open use that performs r-process nucleosynthesis calculations. Equipped with a simple graphical user interface, r-Java is capable of carrying out nuclear statistical equilibrium (NSE), as well as static and dynamic r-process calculations, for a wide range of input parameters. In this introductory paper, we present the motivation and details behind r-Java and results from our static and dynamic simulations. Static simulations are explored for a range of neutron irradiation and temperatures. Dynamic simulations are studied with a parameterized expansion formula. Our code generates the resulting abundance pattern based on a general entropy expression that can be applied to both degenerate and non-degenerate matter, allowing us to track the rapid density and temperature evolution of the ejecta during the initial stages of ejecta expansion. At present, our calculations are limited to the waiting-point approximation. We encourage the nuclear astrophysics community to provide feedback on the code and related documentation, which is available for download from the website of the Quark-Nova Project: http://quarknova.ucalgary.ca/.

  20. Nuclear data for r-process models from ion trap measurements

    NASA Astrophysics Data System (ADS)

    Clark, Jason

    2016-06-01

    To truly understand how elements are created in the universe via the astrophysical r process, accurate nuclear data are required. Historically, the isotopes involved in the r process have been difficult to access for study, but the development of new facilities and measurement techniques have put many of the r-process isotopes within reach. This paper will discuss the new CARIBU facility at Argonne National Laboratory and two pieces of experimental equipment, the Beta-decay Paul Trap and the Canadian Penning Trap, that will dramatically increase the nuclear data available for models of the astrophysical r process.

  1. R-process enrichment from a single event in an ancient dwarf galaxy

    NASA Astrophysics Data System (ADS)

    Ji, Alexander P.; Frebel, Anna; Chiti, Anirudh; Simon, Joshua D.

    2016-03-01

    Elements heavier than zinc are synthesized through the rapid (r) and slow (s) neutron-capture processes. The main site of production of the r-process elements (such as europium) has been debated for nearly 60 years. Initial studies of trends in chemical abundances in old Milky Way halo stars suggested that these elements are produced continually, in sites such as core-collapse supernovae. But evidence from the local Universe favours the idea that r-process production occurs mainly during rare events, such as neutron star mergers. The appearance of a plateau of europium abundance in some dwarf spheroidal galaxies has been suggested as evidence for rare r-process enrichment in the early Universe, but only under the assumption that no gas accretes into those dwarf galaxies; gas accretion favours continual r-process enrichment in these systems. Furthermore, the universal r-process pattern has not been cleanly identified in dwarf spheroidals. The smaller, chemically simpler, and more ancient ultrafaint dwarf galaxies assembled shortly after the first stars formed, and are ideal systems with which to study nucleosynthesis events such as the r-process. Reticulum II is one such galaxy. The abundances of non-neutron-capture elements in this galaxy (and others like it) are similar to those in other old stars. Here, we report that seven of the nine brightest stars in Reticulum II, observed with high-resolution spectroscopy, show strong enhancements in heavy neutron-capture elements, with abundances that follow the universal r-process pattern beyond barium. The enhancement seen in this ‘r-process galaxy’ is two to three orders of magnitude higher than that detected in any other ultrafaint dwarf galaxy. This implies that a single, rare event produced the r-process material in Reticulum II. The r-process yield and event rate are incompatible with the source being ordinary core-collapse supernovae, but consistent with other possible sources, such as neutron star mergers.

  2. R-process enrichment from a single event in an ancient dwarf galaxy.

    PubMed

    Ji, Alexander P; Frebel, Anna; Chiti, Anirudh; Simon, Joshua D

    2016-03-31

    Elements heavier than zinc are synthesized through the rapid (r) and slow (s) neutron-capture processes. The main site of production of the r-process elements (such as europium) has been debated for nearly 60 years. Initial studies of trends in chemical abundances in old Milky Way halo stars suggested that these elements are produced continually, in sites such as core-collapse supernovae. But evidence from the local Universe favours the idea that r-process production occurs mainly during rare events, such as neutron star mergers. The appearance of a plateau of europium abundance in some dwarf spheroidal galaxies has been suggested as evidence for rare r-process enrichment in the early Universe, but only under the assumption that no gas accretes into those dwarf galaxies; gas accretion favours continual r-process enrichment in these systems. Furthermore, the universal r-process pattern has not been cleanly identified in dwarf spheroidals. The smaller, chemically simpler, and more ancient ultrafaint dwarf galaxies assembled shortly after the first stars formed, and are ideal systems with which to study nucleosynthesis events such as the r-process. Reticulum II is one such galaxy. The abundances of non-neutron-capture elements in this galaxy (and others like it) are similar to those in other old stars. Here, we report that seven of the nine brightest stars in Reticulum II, observed with high-resolution spectroscopy, show strong enhancements in heavy neutron-capture elements, with abundances that follow the universal r-process pattern beyond barium. The enhancement seen in this 'r-process galaxy' is two to three orders of magnitude higher than that detected in any other ultrafaint dwarf galaxy. This implies that a single, rare event produced the r-process material in Reticulum II. The r-process yield and event rate are incompatible with the source being ordinary core-collapse supernovae, but consistent with other possible sources, such as neutron star mergers. PMID

  3. 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.

  4. Radiation processing in india-current R & D activities

    NASA Astrophysics Data System (ADS)

    Majali, A. B.; Sabharwal, S.

    1995-09-01

    Radiation processing is an area of vigorous activity in today's India. With the indigenous expertise in Co source and irradiator technology, potentially promising applications such as sustained drug delivery systems, vulcanization of natural rubber latex (RVNRL), and degradation of polytetrafluoroethylene (PTFE) are presently investigated. Over the last four years, technologies for RVNRL and PTFE degradation have been scaled upto pilot scale operations, while radiation polymerized polymer systems have been developed for controlled release of certain drugs. With the commissioning of the 2 MeV EB machine in late 1988, a few EB based processes have also been commercially exploited. The paper briefly reviews these and presents the significant results obtained.

  5. A single prolific r-process event preserved in an ultra-faint dwarf galaxy

    NASA Astrophysics Data System (ADS)

    Ji, Alexander; Frebel, Anna; Chiti, Anirudh; Simon, Joshua

    2016-03-01

    The heaviest elements in the periodic table are synthesized through the r-process, but the astrophysical site for r-process nucleosynthesis is still unknown. Ultra-faint dwarf galaxies contain a simple fossil record of early chemical enrichment that may determine this site. Previous measurements found very low levels of neutron-capture elements in ultra-faint dwarfs, preferring supernovae as the r-process site. I present high-resolution chemical abundances of nine stars in the recently discovered ultra-faint dwarf Reticulum II, which display extremely enhanced r-process abundances 2-3 orders of magnitude higher than the other ultra-faint dwarfs. Stars with such extreme r-process enhancements are only rarely found in the Milky Way halo. The r-process abundances imply that the neutron-capture material in Reticulum II was synthesized in a single prolific event that is incompatible with r-process yields from ordinary core-collapse supernovae. Reticulum II provides an opportunity to discriminate whether the source of this pure r-process signature is a neutron star merger or magnetorotationally driven supernova. The single event is also a uniquely stringent constraint on the metal mixing and star formation history of this ultra-faint dwarf galaxy.

  6. 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.

  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. Decay of the r-PROCESS Nuclides 137,138,139Sb and the A=130 Solar r-PROCESS Abundance Peak

    NASA Astrophysics Data System (ADS)

    Arndt, O.; Kratz, K.-L.; Farouqi, K.; Pfeiffer, B.; Hennrich, S.; Jost, C. J.; Walters, W. B.; Stoyer, M. A.; Köster, U.; Fedosseev, V. N.; Hecht, A. A.; Shergur, J.; Hoteling, N.; Wöhr, A.

    2013-03-01

    Half-life and β-delayed neutron branching values of 492(25) ms and 49(8)%, 350(15) ms and 72(8)%, and 93(13) ms and 90(10)% for the r-process nuclei 137,138,139Sb, respectively, have been measured at CERN/ISOLDE by simultaneously counting β particles and β-delayed neutrons. The sources were prepared by using the selective ionization of Sb with the Resonance Ionization Laser Ion Source and the High-Resolution Mass Separator. These new half-lives and β-delayed neutron branching values are compared with calculated values for both spherical and deformed shapes. The data have been incorporated into parameterized nucleosynthesis calculations of the r-process in high-entropy winds of core-collapse supernovae in order to study the properties of the A=130 Solar-System r-process abundance peak.

  9. Sensitivity studies for the main r process: β-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 β-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 β-decay rates in the r process. We perform β-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, γ)-(γ, 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 β-decay rates continue to shape the final abundance pattern through the post-equilibrium phase, for as long as neutron capture competes with β decay. Many of the lifetimes important for this phase of the r process are within current or near future experimental reach.

  10. 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

  11. 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.

  12. 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.

  13. Relative Contributions of the Weak, Main, and Fission-recycling r-process

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    There has been a persistent conundrum in attempts to model the nucleosynthesis of heavy elements by rapid neutron capture (the r-process). Although the locations 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 nuclides above and below the r-process peaks in main or weak r-process models (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 (NSMs). 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 NSMs for the fission-recycling r-process.

  14. 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

  15. R-parity violation in flavor-changing neutral current processes and top quark decays

    NASA Astrophysics Data System (ADS)

    Agashe, K.; Graesser, M.

    1996-10-01

    We show that supersymmetric R-parity-breaking (R/p) interactions always result in flavor changing neutral current processes. Within a single coupling scheme, these processes can be avoided in either the charge +2/3 or the charge -1/3 quark sector, but not both. These processes are used to place constraints on R/p couplings. The constraints on the first and the second generations are better than those existing in the literature. The R/p interactions may result in new top quark decays. Some of these violate electron-muon universality or produce a surplus of b quark events in tt¯ decays. Results from the CDF experiment are used to bound these R/p couplings.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Inferring Nuclear Structure Trends of r-PROCESS Nuclei from β-DECAY Measurements

    NASA Astrophysics Data System (ADS)

    Pereira, J.

    2013-03-01

    The present paper reports on several r-process motivated β-decay experiments undertaken at the National Superconducting Cyclotron Laboratory. β-decay half-lives and β-delayed neutron-emission probabilities were measured for neutron-rich nuclei in the region A=80-110. The data are discussed on the basis of quasi-random phase approximation calculations. The emphasis is made on the impact of these data upon calculations of r-process abundances.

  2. Impact of new β-decay half-lives on r-process nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Nishimura, Nobuya; Kajino, Toshitaka; Mathews, Grant J.; Nishimura, Shunji; Suzuki, Toshio

    2012-04-01

    We investigate the effects of newly measured β-decay half-lives on r-process nucleosynthesis. These new rates were determined by recent experiments at the radioactive isotope beam factory facility in the RIKEN Nishina Center. We adopt an r-process nucleosynthesis environment based on a magnetohydrodynamic supernova explosion model that includes strong magnetic fields and rapid rotation of the progenitor. A number of the new β-decay rates are for nuclei on or near the r-process path, and hence they affect the nucleosynthesis yields and time scale of the r-process. The main effect of the newly measured β-decay half-lives is an enhancement in the calculated abundance of isotopes with mass number A=110-120 relative to calculated abundances based upon β-decay rates estimated with the finite-range droplet mass model. This effect slightly alleviates, but does not fully explain, the tendency of r-process models to underproduce isotopes with A=110-120 compared to the solar-system r-process abundances.

  3. The r-PROCESS in Supernova Explosions from the Collapse of ONeMg Cores

    NASA Astrophysics Data System (ADS)

    Wanajo, Shinya; Itoh, Naoki; Nomoto, Ken'ichi; Ishimaru, Yuhri; Beers, Timothy C.

    2005-12-01

    We examine r-process nucleosynthesis in a "prompt supernova explosion" from an 8 - 10M⊙ progenitor star. In the present model, the progenitor star has formed an oxygen-neon-magnesium core at its center. The core-collapse simulations are performed with a one-dimension, Newtonian hydrodynamic code. We simulate energetic prompt explosions by enhancement of the shock-heating energy, in order to investigate conditions necessary for the production of r-process nuclei in such events. The r-process nucleosynthesis is calculated using a nuclear reaction network code including relevant neutron-rich isotopes with reactions among them. The highly neutronized ejecta (Ye ≈ 0.14 - 0.20) leads to robust production of r-process nuclei; their relative abundances are in excellent agreement with the solar r-process pattern. Our results suggest that prompt explosions of 8 - 10M⊙ stars with oxygen-neon-magnesium cores can be a promising site of r-process nuclei.

  4. The production of transuranium elements by the r-process nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Goriely, S.; Martínez Pinedo, G.

    2015-12-01

    The production of super-heavy transuranium elements by stellar nucleosynthesis processes remains an open question. The most promising process that could potentially give rise to the formation of such elements is the so-called rapid neutron-capture process, or r-process, known to be at the origin of approximately half of the A > 60 stable nuclei observed in nature. However, despite important efforts, the astrophysical site of the r-process remains unidentified. Here, we study the r-process nucleosynthesis in material that is dynamically ejected by tidal and pressure forces during the merging of binary neutron stars. Neutron star mergers could potentially be the dominant r-process site in the Galaxy, but also due to the extreme neutron richness found in such environment, could potentially synthesise super-heavy elements. 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. During the neutron irradiation, nuclei up to charge numbers Z ≃ 110 and mass number A ≃ 340 are produced, with a major peak production at the N = 184 shell closure, i.e. around A ≃ 280. Super-heavy nuclei with Z > 110 can hardly be produced due to the efficient fission taking place along those isotopic chains. Long-lived transuranium nuclei are inevitably produced by the r-process. The predictions concerning the production of transuranium nuclei remain however very sensitive to the predictions of fission barrier heights for such super-heavy nuclei. More nuclear predictions within different microscopic approaches are needed.

  5. 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 β-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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    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.

  8. 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.

  9. 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).

  10. The r-PROCESS IN THE NEUTRINO-DRIVEN WIND FROM A BLACK-HOLE TORUS

    SciTech Connect

    Wanajo, Shinya; Janka, Hans-Thomas E-mail: thj@mpa-garching.mpg.de

    2012-02-20

    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{sub Sun} 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 ({approx}30 per nucleon in units of the Boltzmann constant) and moderate expansion timescales ({approx}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{sub e,min} {approx} 0.2, is achieved. In the case of Y{sub e,min} {approx} 0.3, the production of r-elements beyond A {approx} 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 {approx}1 Multiplication-Sign 10{sup -3} M{sub Sun }. If our model was representative, this demands a Galactic event rate of {approx}2 Multiplication-Sign 10{sup -4} yr{sup -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. 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, β - 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 β -decay half-lives found in this region. The third peak around A ˜195 is generated in a competition between neutron captures and β 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

  13. 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.

  14. PRIMORDIAL r-PROCESS DISPERSION IN METAL-POOR GLOBULAR CLUSTERS

    SciTech Connect

    Roederer, Ian U.

    2011-05-01

    Heavy elements, those produced by neutron-capture reactions, have traditionally shown no star-to-star dispersion in all but a handful of metal-poor globular clusters (GCs). Recent detections of low [Pb/Eu] ratios or upper limits in several metal-poor GCs indicate that the heavy elements in these GCs were produced exclusively by an r-process. Re-examining GC heavy element abundances from the literature, we find unmistakable correlations between the [La/Fe] and [Eu/Fe] ratios in four metal-poor GCs (M5, M15, M92, and NGC 3201), only two of which were known previously. This indicates that the total r-process abundances vary from star to star (by factors of 2-6) relative to Fe within each GC. We also identify potential dispersion in two other GCs (M3 and M13). Several GCs (M12, M80, and NGC 6752) show no evidence of r-process dispersion. The r-process dispersion is not correlated with the well-known light element dispersion, indicating that it was present in the gas throughout the duration of star formation. The observations available at present suggest that star-to-star r-process dispersion within metal-poor GCs may be a common but not ubiquitous phenomenon that is neither predicted by nor accounted for in current models of GC formation and evolution.

  15. 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.

  16. Beta-decay half-lives for the r-process nuclei

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    For nucleosynthesis calculations of the r-process it is important to know beta-decay half-lives of short-lived neutron-rich nuclei. In the present paper these characteristics are calculated for an extended number of neutron-rich nuclei, important for the r-process. In our calculations the model description of beta-strength functions based on Finite Fermi-Systems Theory is used. The comparison with other predictions and experimental data is done. It is shown that the accuracy of beta-decay half-lives of short-lived neutron-rich nuclei is increasing with increasing neutron excess and can be used for modeling of nucleosynthesis of heavy nuclei in the r-process. For nuclei heavier than lead the half-lives of neutron-rich nuclei are on average 10 times smaller, than proposed of other predictions.

  17. 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

  18. 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

  19. 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.

  20. Influence of shell-quenching far from stability on the astrophysical r-process

    NASA Astrophysics Data System (ADS)

    Chen, B.; Dobaczewski, J.; Kratz, K.-L.; Langanke, K.; Pfeiffer, B.; Thielemann, F.-K.; Vogel, P.

    1995-02-01

    Comparison of results from r-process calculations within the waiting-point assumption and the r-process component (Nr,solar) of the solar-system composition of heavy elements, permits to test nuclear structure far from stability. Previous investigations, making use of nuclear mass predictions from global macroscopic-microscopic models, showed abundance deficiencies around A ~= 120 and 140, indicating an overly strong N = 82 strength (some models also showed problems around A ~= 180 related to the N = 126 shell). In this paper we calculate masses based on Skyrme interactions locally around N = 82, within the HF+BCS method with the SIII interaction and the HFB theory with SkP interaction. The shell-quenching obtained in the latter approach results in a considerable improvement of the global Nr,solar fit, indicating a solution to a puzzle existing in r-process nucleosynthesis.

    1. Chemical Evolution of R-process Elements in the Hierarchical Galaxy Formation

      NASA Astrophysics Data System (ADS)

      Komiya, Yutaka; Shigeyama, Toshikazu

      2016-08-01

      The main astronomical source of r-process elements has not yet been identified. One plausible site is neutron star mergers (NSMs). From the perspective of Galactic chemical evolution, however, it has been pointed out that the NSM scenario is incompatible with observations. Recently, Tsujimoto & Shigeyama (2014) pointed out that NSM ejecta can spread into much larger volume than ejecta from a supernova. We re-examine the chemical evolution of r-process elements under the NSM scenario considering this difference in propagation of the ejecta. We find that the NSM scenario can be compatible with the observed abundances of the Milky Way halo stars.

    2. 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.

    3. 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 ν-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 ν emission model and to ν 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

    4. Neutron Rich Nuclei in a New Binding Energy Formula and the Astrophysical r-PROCESS

      NASA Astrophysics Data System (ADS)

      Lahiri, Chirashree; Gangopadhyay, G.

      Neutron rich nuclei has been studied with a new phenomenological mass formula. Predictions of different mass formulas for the location of the neutron drip line are compared with those from the present calculation. The implications of the new mass formula for r-process nucleosynthesis are discussed. It is found that though the neutron drip line obtained from this formula differs substantially from other formulas, the r-process abundance upto mass 200 are unlikely to be significantly different. The errors inherent in the mass formula are found to play an insignificant role beyond mass A = 80.

    5. 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.

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

      NASA Astrophysics Data System (ADS)

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

      2016-01-01

      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 238U beam at GSI we were able to measure such properties for several neutron-rich nuclei from 208Hg to 218Pb. 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 ∼ 126 are required for a reliable modelling of the underlying nuclear structure, and for performing more realistic r-process abundance calculations.

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

      NASA Astrophysics Data System (ADS)

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

      2016-01-01

      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, β-decay and neutron capture rates, as well as β-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 toward addressing the grand challenge of 'How were the elements from iron to uranium made?'.

    8. Influence of neutrinos on r-process nucleosynthesis in black hole-neutron star mergers

      NASA Astrophysics Data System (ADS)

      Lippuner, Jonas; Roberts, Luke F.; Duez, Matthew D.; Faber, Joshua A.; Foucart, Francois; Lombardi, James C.; Ott, Christian D.; Ponce, Marcelo

      2016-03-01

      During a black hole-neutron star merger, baryonic material can be dynamically ejected. Because this ejecta is extremely neutron-rich, the r-process rapidly synthesizes heavy nuclides as the material expands and cools. This can contribute to galactic chemical evolution of the r-process elements and lead to a short-lived optical transient, called a kilonova, powered by the radioactive decay of the heavy nuclides. We use the nuclear reaction network SkyNet to model r-process nucleosynthesis under varying levels of neutrino irradiation by post-processing tracer particles in the ejecta of a full numerical relativity simulation of a black hole-neutron star merger. We find the ejected material robustly produces the second and third r-process peaks, whose abundances remain unchanged even for very high neutrino luminosities, due to the rapid velocities of the outflow. Nonetheless, we find that neutrinos can have an impact on the detailed abundance pattern by significantly enhancing the amount of material produced in the first peak around A ~ 78 . Electron neutrinos are captured by neutrons to produce protons while neutron capture is occurring. These protons rapidly form low-mass seed nuclei, a fraction of which eventually ends up in the first peak after neutron capture ceases. Partially supported by NASA and NSF under AST-1205732, AST-1313091, AST-1333520, PF3-140114, PF4-150122, and PHY-1151197.

    9. Tracking the interactions of rRNA processing proteins during nucleolar assembly in living cells.

      PubMed

      Angelier, Nicole; Tramier, Marc; Louvet, Emilie; Coppey-Moisan, Maïté; Savino, Tula M; De Mey, Jan R; Hernandez-Verdun, Danièle

      2005-06-01

      Reorganization of the nuclear machinery after mitosis is a fundamental but poorly understood process. Here, we investigate the recruitment of the nucleolar processing proteins in the nucleolus of living cells at the time of nucleus formation. We question the role of the prenucleolar bodies (PNBs), during migration of the processing proteins from the chromosome periphery to sites of rDNA transcription. Surprisingly, early and late processing proteins pass through the same PNBs as demonstrated by rapid two-color four-dimensional imaging and quantification, whereas a different order of processing protein recruitment into nucleoli is supported by differential sorting. Protein interactions along the recruitment pathway were investigated using a promising time-lapse analysis of fluorescence resonance energy transfer. For the first time, it was possible to detect in living cells the interactions between proteins of the same rRNA processing machinery in nucleoli. Interestingly interactions between such proteins also occur in PNBs but not at the chromosome periphery. The dynamics of these interactions suggests that PNBs are preassembly platforms for rRNA processing complexes. PMID:15814843

    10. The cytoplasmic mRNA degradation factor Pat1 is required for rRNA processing.

      PubMed

      Muppavarapu, Mridula; Huch, Susanne; Nissan, Tracy

      2016-04-01

      Pat1 is a key cytoplasmic mRNA degradation factor, the loss of which severely increases mRNA half-lives. Several recent studies have shown that Pat1 can enter the nucleus and can shuttle between the nucleus and the cytoplasm. As a result, many nuclear roles have been proposed for Pat1. In this study, we analyzed four previously suggested nuclear roles of Pat1 and show that Pat1 is not required for efficient pre-mRNA splicing or pre-mRNA decay in yeast. However, lack of Pat1 results in accumulation of pre-rRNA processing intermediates. Intriguingly, we identified a novel genetic relationship between Pat1 and the rRNA decay machinery, specifically the exosome and the TRAMP complex. While the pre-rRNA processing intermediates that accumulate in the pat1 deletion mutant are, at least to some extent, recognized as aberrant by the rRNA degradation machinery, it is unlikely that these accumulations are the cause of their synthetic sick relationship. Here, we show that the dysregulation of the levels of mRNAs related to ribosome biogenesis could be the cause of the accumulation of the pre-rRNA processing intermediates. Although our results support a role for Pat1 in transcription, they nevertheless suggest that the primary cause of the dysregulated mRNA levels is most likely due to Pat1's role in mRNA decapping and mRNA degradation. PMID:26918764

    11. A late-acting quality control process for mature eukaryotic rRNAs.

      PubMed

      LaRiviere, Frederick J; Cole, Sarah E; Ferullo, Daniel J; Moore, Melissa J

      2006-11-17

      Ribosome biogenesis is a multifaceted process involving a host of trans-acting factors mediating numerous chemical reactions, RNA conformational changes, and RNA-protein associations. Given this high degree of complexity, tight quality control is likely crucial to ensure structural and functional integrity of the end products. We demonstrate that ribosomal RNAs (rRNAs) containing individual point mutations, in either the 25S peptidyl transferase center or 18S decoding site, that adversely affect ribosome function are strongly downregulated in Saccharomyces cerevisiae. This downregulation occurs via decreased stability of the mature rRNA contained in fully assembled ribosomes and ribosomal subunits. Thus, eukaryotes possess a quality-control mechanism, nonfunctional rRNA decay (NRD), capable of detecting and eliminating the rRNA component of mature ribosomes. PMID:17188037

    12. 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.

    13. Compatibility of manufacturing process fluids with R-134a and polyolester lubricant. Final report

      SciTech Connect

      Cavestri, R.C.; Schooley, D.L.

      1996-07-01

      This report includes a broad list of processing fluids that are known to be used to manufacture air conditioning and refrigeration products. Sixty-four process fluids from this list were selected for compatibility studies with R-134a and ICI EMKARATE RL32H (32 ISO) polyolester lubricant. Solutions or suspensions of the process fluid residues in polyolester lubricant were heated for 14 days at 175{degrees}C (347{degrees}F) in evacuated sealed glass tubes containing only valve steel coupons. Miscibility tests were performed at 90 wt.% R-134a, 10 wt.% polyolester lubricant with process fluid residue contaminate and were scanned in 10{degrees}C (18{degrees}F) increments over a temperature range of ambient to -40{degrees}C (-40{degrees}F). Any sign of turbidity, haze formation or oil separation was considered the immiscibility point.

    14. Astrophysical site(s) of r-process elements in galactic chemodynamical evolution model

      NASA Astrophysics Data System (ADS)

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

      2016-02-01

      Astrophysical site(s) of rapid neutron-capture process (r-process) is (are) not identified yet. Although core-collapse supernovae have been regarded as one of the possible candidates of the astrophysical site of r-process, nucleosynthesis studies suggest that serious difficulties in core-collapse supernovae to produce heavy elements with mass number of ≳110. Recent studies show that neutron star mergers (NSMs) can synthesize these elements due to their neutron rich environment. Some chemical evolution studies of the Milky Way halo, however, hardly reproduce the observed star-to-star scatters of the abundance ratios of r-process elements (e.g., Eu) in extremely metal-poor stars. This is because of their low rate (˜ 10-4 yr-1 for a Milky Way size galaxy) and long merger time (≳ 100 Myr). This problem might be solved if the stars in the Galactic halo are consisted of the stars formed in dwarf galaxies where the star formation efficiencies were very low. In this study, we carry out numerical simulations of galactic chemo-dynamical evolution using an N-body/smoothed particle hydrodynamics code. We construct detailed chemo-dynamical evolution model for the Local Group dwarf spheroidal galaxies (dSphs) assuming that the NSMs are the major source of r-process elements. Our models successfully reproduce the observed dispersion in [Eu/Fe] as a function of [Fe/H] if we set merger time of NSMs, ≲ 300 Myr with the Galactic NSM rate of ˜ 10-4 yr-1. In addition, our results are consistent with the observed metallicity distribution of dSphs. In the early phase (≲1 Gyr) of galaxy evolution is constant due to low star formation efficiency of dSphs. This study supports the idea that NSMs are the major site of r-process nucleosynthesis.

    15. The even-odd systematics in R-process nuclide abundances

      NASA Technical Reports Server (NTRS)

      Marti, K.; Suess, H. E.

      1988-01-01

      The paper reports and discusses solar system N(R) abundances for nuclides A greater than 70, obtained as differences between measured solar system abundances and calculated S-process contributions. The abundance peak at A of about 163 in the rare earth element region reveals properties which are similar to those of the R-process peaks corresponding to magic neutron numbers N = 82 and N = 126. Systematic differences in the N(R) abundances of even-A and odd-A nuclides are restricted to specific mass regions. It is concluded that these differences are most probably related to the properties of nuclear species during beta(-) decay to the stability valley.

    16. 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 α-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.

    17. 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.

    18. 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.

    19. New Neutron-capture Measurements in 23 Open Clusters. I. The r-Process

      NASA Astrophysics Data System (ADS)

      Overbeek, Jamie C.; Friel, Eileen D.; Jacobson, Heather R.

      2016-06-01

      Neutron-capture elements, those with Z > 35, are the least well understood in terms of nucleosynthesis and formation environments. The rapid neutron-capture, or r-process, elements are formed in the environments and/or remnants of massive stars, while the slow neutron-capture, or s-process, elements are primarily formed in low-mass AGB stars. These elements can provide much information about Galactic star formation and enrichment, but observational data are limited. We have assembled a sample of 68 stars in 23 open clusters that we use to probe abundance trends for six neutron-capture elements (Eu, Gd, Dy, Mo, Pr, and Nd) with cluster age and location in the disk of the Galaxy. In order to keep our analysis as homogeneous as possible, we use an automated synthesis fitting program, which also enables us to measure multiple (3–10) lines for each element. We find that the pure r-process elements (Eu, Gd, and Dy) have positive trends with increasing cluster age, while the mixed r- and s-process elements (Mo, Pr, and Nd) have insignificant trends consistent with zero. Pr, Nd, Eu, Gd, and Dy have similar, slight (although mostly statistically significant) gradients of ∼0.04 dex kpc‑1. The mixed elements also appear to have nonlinear relationships with R GC.

    20. New Neutron-capture Measurements in 23 Open Clusters. I. The r-Process

      NASA Astrophysics Data System (ADS)

      Overbeek, Jamie C.; Friel, Eileen D.; Jacobson, Heather R.

      2016-06-01

      Neutron-capture elements, those with Z > 35, are the least well understood in terms of nucleosynthesis and formation environments. The rapid neutron-capture, or r-process, elements are formed in the environments and/or remnants of massive stars, while the slow neutron-capture, or s-process, elements are primarily formed in low-mass AGB stars. These elements can provide much information about Galactic star formation and enrichment, but observational data are limited. We have assembled a sample of 68 stars in 23 open clusters that we use to probe abundance trends for six neutron-capture elements (Eu, Gd, Dy, Mo, Pr, and Nd) with cluster age and location in the disk of the Galaxy. In order to keep our analysis as homogeneous as possible, we use an automated synthesis fitting program, which also enables us to measure multiple (3–10) lines for each element. We find that the pure r-process elements (Eu, Gd, and Dy) have positive trends with increasing cluster age, while the mixed r- and s-process elements (Mo, Pr, and Nd) have insignificant trends consistent with zero. Pr, Nd, Eu, Gd, and Dy have similar, slight (although mostly statistically significant) gradients of ˜0.04 dex kpc‑1. The mixed elements also appear to have nonlinear relationships with R GC.

    1. Constraints on Neutron Density and Temperature Conditions for Astrophysical r-PROCESS from Updated Nuclear Masses

      NASA Astrophysics Data System (ADS)

      Xu, X. D.; Sun, B.; Niu, Z. M.; Li, Z.; Meng, J.

      2013-11-01

      Based on the (n, γ) ⇌ (γ, n) equilibrium, the neutron density and temperature conditions required for the r-process are constrained with updated nuclear masses. It is found that the uncertainty of determined neutron density and temperature ranges can be greatly minimized when mass values tabulated in the latest Atomic Mass Evaluation AME2011-preview are employed.

    2. r-Process Elements as Tracers of Enrichment Processes in the Early Halo

      NASA Astrophysics Data System (ADS)

      Andersen, Johannes; Nordström, Birgitta; Hansen, Terese T.

      2016-08-01

      Significant minorities of extremely metal-poor (EMP) halo stars exhibit dramatic excesses of neutron capture elements. The standard scenario for their origin is mass transfer and dilution in binary systems, but requires them to be binaries. If not, these excesses must have been implanted in them from birth by processes that are not included in current models of SN II chemical enrichment. The binary population of such EMP subgroups is a test of this scenario.

    3. The impact of nuclear mass models on r-process nucleosynthesis network calculations

      NASA Astrophysics Data System (ADS)

      Vaughan, Kelly

      2002-10-01

      An insight into understanding various nucleosynthesis processes is via modelling of the process with network calculations. My project focus is r-process network calculations where the r-process is nucleosynthesis via rapid neutron capture thought to take place in high entropy supernova bubbles. One of the main uncertainties of the simulations is the Nuclear Physics input. My project investigates the role that nuclear masses play in the resulting abundances. The code tecode, involves rapid (n,γ) capture reactions in competition with photodisintegration and β decay onto seed nuclei. In order to fully analyze the effects of nuclear mass models on the relative isotopic abundances, calculations were done from the network code, keeping the initial environmental parameters constant throughout. The supernova model investigated by Qian et al (1996) in which two r-processes, of high and low frequency with seed nucleus ^90Se and of fixed luminosity (fracL_ν_e(0)r_7(0)^2 ˜= 8.77), contribute to the nucleosynthesis of the heavier elements. These two r-processes, however, do not contribute equally to the total abundance observed. The total isotopic abundance produced from both events was therefore calculated using equation refabund. Y(H+L) = fracY(H)+fY(L)f+1 <~belabund where Y(H) denotes the relative isotopic abundance produced in the high frequency event, Y(L) corresponds to the low freqeuncy event and f is the ratio of high event matter to low event matter produced. Having established reliable, fixed parameters, the network code was run using data files containing parameters such as the mass excess, neutron separation energy, β decay rates and neutron capture rates based around three different nuclear mass models. The mass models tested are the HFBCS model (Hartree-Fock BCS) derived from first principles, the ETFSI-Q model (Extended Thomas-Fermi with Strutinsky Integral including shell Quenching) known for its particular successes in the replication of Solar System

    4. Detailed Chemical Abundances in the r-process-rich Ultra-faint Dwarf Galaxy Reticulum 2

      NASA Astrophysics Data System (ADS)

      Roederer, Ian U.; Mateo, Mario; Bailey, John I., III; Song, Yingyi; Bell, Eric F.; Crane, Jeffrey D.; Loebman, Sarah; Nidever, David L.; Olszewski, Edward W.; Shectman, Stephen A.; Thompson, Ian B.; Valluri, Monica; Walker, Matthew G.

      2016-03-01

      The ultra-faint dwarf (UFD) galaxy Reticulum 2 (Ret 2) was recently discovered in images obtained by the Dark Energy Survey. We have observed the four brightest red giants in Ret 2 at high spectral resolution using the Michigan/Magellan Fiber System. We present detailed abundances for as many as 20 elements per star, including 12 elements heavier than the Fe group. We confirm previous detection of high levels of r-process material in Ret 2 (mean [Eu/Fe] = +1.69 ± 0.05) found in three of these stars (mean [Fe/H] = -2.88 ± 0.10). The abundances closely match the r-process pattern found in the well-studied metal-poor halo star CS 22892-052. Such r-process-enhanced stars have not been found in any other UFD galaxy, though their existence has been predicted by at least one model. The fourth star in Ret 2 ([Fe/H] = -3.42 ± 0.20) contains only trace amounts of Sr ([Sr/Fe] = -1.73 ± 0.43) and no detectable heavier elements. One r-process enhanced star is also enhanced in C (natal [C/Fe] ≈ +1.1). This is only the third such star known, which suggests that the nucleosynthesis sites leading to C and r-process enhancements are decoupled. The r-process-deficient star is enhanced in Mg ([Mg/Fe] = +0.81 ± 0.14), and the other three stars show normal levels of α-enhancement (mean [Mg/Fe] = +0.34 ± 0.03). The abundances of other α and Fe-group elements closely resemble those in UFD galaxies and metal-poor halo stars, suggesting that the nucleosynthesis that led to the large r-process enhancements either produced no light elements or produced light-element abundance signatures indistinguishable from normal supernovae. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

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

      NASA Astrophysics Data System (ADS)

      Hansen, C. J.; Primas, F.; Hartman, H.; Kratz, K.-L.; Wanajo, S.; Leibundgut, B.; Farouqi, K.; Hallmann, O.; Christlieb, N.; Nilsson, H.

      2012-09-01

      Context. The rapid neutron-capture process, which created about half of the heaviest elements in the solar system, is believed to have been unique. Many recent studies have shown that this uniqueness is not true for the formation of lighter elements, in particular those in the atomic number range 38 < Z < 48. Among these, 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. We therefore 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. Aims: We study the abundances of seven elements (Sr, Y, Zr, Pd, Ag, Ba, and Eu) to gain insight into the formation process of the elements and explore in depth the nature of the second r-process. Methods: By adopting a homogeneous one-dimensional local thermodynamic equilibrium (1D LTE) analysis of 71 stars, we derive stellar abundances using the spectral synthesis code MOOG, and the MARCS model atmospheres. We calculate abundance ratio trends and compare the derived abundances to site-dependent yield predictions (low-mass O-Ne-Mg core-collapse supernovae and parametrised high-entropy winds), to extract characteristics of the second r-process. Results: The seven elements are tracers of different (neutron-capture) processes, which in turn allows us to constrain the formation process(es) of Pd and Ag. The abundance ratios of the heavy elements are found to be correlated and anti-correlated. These trends lead to clear indications that a second/weak r-process, is responsible for the formation of Pd and Ag. On the basis of the comparison to the model predictions, we find that the conditions under which this process takes place differ from those for the main r-process in needing lower neutron number densities, lower neutron

    6. 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.

    7. Radiative neutron captures by neutron-rich nuclei and the r-process nucleosynthesis

      NASA Astrophysics Data System (ADS)

      Goriely, S.

      1998-09-01

      The radiative neutron capture by neutron-rich nuclei is estimated with an improved description of the electric giant dipole resonance. In addition, 3 major effects affecting the capture rates by exotic neutron-rich nuclei are studied. These concern the existence of a low-energy E1 pygmy resonance, the overestimate of the statistical predictions for resonance-deficient nuclei and the direct capture mechanism. The total (n,γ) reaction rates including these 3 effects are evaluated for 3100 neutron-rich nuclei and used in parametric r-process calculations to analyze their impact on the r-abundance distribution.

    8. Pol I Transcription and Pre-rRNA Processing Are Coordinated in a Transcription-dependent Manner in Mammalian Cells

      PubMed Central

      Kopp, K.; Gasiorowski, J. Z.; Chen, D.; Gilmore, R.; Norton, J. T.; Wang, C.; Leary, D. J.; Chan, E.K.L.; Dean, D. A.

      2007-01-01

      Pre-rRNA synthesis and processing are key steps in ribosome biogenesis. Although recent evidence in yeast suggests that these two processes are coupled, the nature of their association is unclear. In this report, we analyze the coordination between rDNA transcription and pre-rRNA processing in mammalian cells. We found that pol I transcription factor UBF interacts with pre-rRNA processing factors as analyzed by immunoprecipitations, and the association depends on active rRNA synthesis. In addition, injections of plasmids containing the human rDNA promoter and varying lengths of 18S rDNA into HeLa nuclei show that pol I transcription machinery can be recruited to rDNA promoters regardless of the product that is transcribed, whereas subgroups of pre-rRNA processing factors are recruited to plasmids only when specific pre-rRNA fragments are produced. Our observations suggest a model for sequential recruitment of pol I transcription factors and pre-rRNA processing factors to elongating pre-rRNA on an as-needed basis rather than corecruitment to sites of active transcription. PMID:17108330

    9. 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

    10. GOES-R AWG product processing system framework: research to operations

      NASA Astrophysics Data System (ADS)

      Li, A.; Sampson, S.; Wolf, W.; Yu, T.; Garcia, R.; Martin, G.; Straka, W.; Fan, M.; Schiffer, E.; Goldberg, M.

      2014-11-01

      GOES-R Algorithm Working Group's (AWG) Product Processing System Framework is currently being run both in operations and in near real-time to support algorithm verification and validation over extended seasonal datasets. The algorithms are being tested using a variety of data sets, including: MODIS, SEVIRI, GOES, VIIRS data, and ABI WRF simulated data. The Advanced Himawari Imager(AHI) data will also be used as ABI proxy data to test the GOES-R algorithms in the Framework. AWG Integration Team (AIT) has developed a suite of tools to monitor product quality, product processing, and system performance for the near real-time product generation. These capabilities have allowed the framework to be expanded for use in transitioning algorithms to operations. The GOES-R AWG Derived Atmospheric Motion Vector Winds algorithm has been successfully updated and transitioned to operations running on existing GOES and VIIRS data. Other GOES-R algorithms that are being upgraded for operational use on VIIRS include the Clouds, Aerosols, and Cryosphere products. In addition, legacy operational cloud systems will be integrated into the Framework. The design details of the AWG Framework, near real-time algorithm product generation system, monitoring tools, transitioning of the framework to operations, and future algorithm implementation plans shall be discussed.

    11. Structural determinants of miR156a precursor processing in temperature-responsive flowering in Arabidopsis

      PubMed Central

      Kim, Wanhui; Kim, Hee-Eun; Jun, A Rim; Jung, Myeong Gyo; Jin, Suhyun; Lee, Joon-Hwa; Ahn, Ji Hoon

      2016-01-01

      MicroRNAs originate from primary transcripts (pri-miRNAs) containing hairpin structures. Plant pri-miRNAs have highly variable structures and little is known about the information encoded in their secondary structures. Arabidopsis miR156 is an ambient temperature-responsive miRNA and plays an important role in regulating flowering time. To identify the structural determinants for miR156 processing, we analyzed the effects of mutations introduced in the upper stem of pri-miR156a on its temperature-dependent processing and flowering time. The levels of pri-miR156a and mature miR156 were opposite at different temperatures. Mutations in the upper stem, especially the region closer to the miR156a/miR156a* duplex, reduced miR156 processing at 23 °C and 16 °C and caused a less severe phenotype compared with the un-mutated construct. Mutation in the second stem near the first cleavage site of pri-miR156a affected miR156 processing at 23 °C, but not at 16 °C. This was also seen in pri-miR172a, another ambient temperature-responsive miRNA. Replacement of the upper stem of pri-miR156a with that of pri-miR172a severely affected miR156 processing and flowering time. These results suggested that the upper stem of pri-miR156a is important for miR156 processing at different temperatures. In particular, the second stem adjacent to the first cleavage site plays a role in the regulation of ambient temperature-responsive flowering. PMID:27335452

    12. The r-process in black hole-neutron star mergers based on a fully general-relativistic simulation

      NASA Astrophysics Data System (ADS)

      Nishimura, N.; Wanajo, S.; Sekiguchi, Y.; Kiuchi, K.; Kyutoku, K.; Shibata, M.

      2016-01-01

      We investigate the black hole-neutron star binary merger in the contest of the r-process nucleosynthesis. Employing a hydrodynamical model simulated in the framework of full general relativity, we perform nuclear reaction network calculations. The extremely neutron-rich matter with the total mass 0.01 M⊙ is ejected, in which a strong r-process with fission cycling proceeds due to the high neutron number density. We discuss relevant astrophysical issues such as the origin of r-process elements as well as the r-process powered electromagnetic transients.

    13. PReMiuM: An R Package for Profile Regression Mixture Models Using Dirichlet Processes

      PubMed Central

      Liverani, Silvia; Hastie, David I.; Azizi, Lamiae; Papathomas, Michail; Richardson, Sylvia

      2016-01-01

      PReMiuM is a recently developed R package for Bayesian clustering using a Dirichlet process mixture model. This model is an alternative to regression models, non-parametrically linking a response vector to covariate data through cluster membership (Molitor, Papathomas, Jerrett, and Richardson 2010). The package allows binary, categorical, count and continuous response, as well as continuous and discrete covariates. Additionally, predictions may be made for the response, and missing values for the covariates are handled. Several samplers and label switching moves are implemented along with diagnostic tools to assess convergence. A number of R functions for post-processing of the output are also provided. In addition to fitting mixtures, it may additionally be of interest to determine which covariates actively drive the mixture components. This is implemented in the package as variable selection. PMID:27307779

    14. Chemical evolution of r-process elements in the Draco dwarf spheroidal galaxy

      NASA Astrophysics Data System (ADS)

      Ishigaki, M. N.; Tsujimoto, T.; Shigeyama, T.; Aoki, W.

      2016-08-01

      A dominant astrophysical site for r-process, which is responsible for producing heavy neutron-capture elements, is unknown. Dwarf spheroidal galaxies around the Milky Way halo provide ideal laboratories to investigate the origin and evolution of r-process elements. We carried out high-resolution spectroscopic observations of three giant stars in the Draco dwarf spheroidal galaxy to estimate their europium abundances. We found that the upper-limits of [Eu/H] are very low in the range [Fe/H] < -2, while this ratio is nearly constant at higher metallicities. This trend is not well reproduced with models which assume that Eu is produced together with Fe by SNe, and may suggest the contribution from other objects such as neutron-star mergers.

    15. Are collapsars responsible for some r-process elements? How could we tell?

      SciTech Connect

      Pruet, J

      2004-04-05

      We consider the possibility that supernovae which form hyper-accreting black holes might be responsible for synthesis of r-process elements with mass A {approx}< 130. Calculations are presented which show that these elements are naturally synthesized in neutron-rich magnetically-dominated bubbles born in the inner regions of a black hole accretion disk. Simple considerations suggest that the total mass ejected in the form of these bubbles is about that needed to account for the entire galactic inventory of the 2nd-peak r-process elements. We also argue that if collapsars are responsible for, e.g., Ag synthesis, then Ag abundances should be correlated with Sc and/or Zn abundances in metal-poor stars.

    16. 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.

    17. 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.

    18. {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.

    19. Neutrino-Induced Neutral-Current Reaction Cross Sections for r-PROCESS Nuclei

      NASA Astrophysics Data System (ADS)

      Langanke, K.; Kolbe, E.

      2002-11-01

      Neutrino-induced reactions play an important role during and after the r-process, if the latter occurs in an environment with extreme neutrino fluxes such as the neutrino-driven wind model or neutron star mergers. Recently we have evaluated the charged-current neutrino-nucleus cross sections relevant for r-process simulations. We extend our approach here to the neutral-current cross sections. Our tabulation considers neutron-rich nuclei with neutron numbers N=41-135 and charge numbers Z=21-82 and lists total as well as partial neutron spallation cross sections. The calculations have been performed within the random phase approximation considering multipole transitions with J<=3 and both parities. The supernova neutrino spectrum is described by a Fermi-Dirac distribution with various temperature parameters between T=2.8 MeV and T=10 MeV and with the degeneracy parameters α=0 and α=3.

    20. Solar r-process-constrained actinide production in neutrino-driven winds of supernovae

      NASA Astrophysics Data System (ADS)

      Goriely, S.; Janka, H.-Th.

      2016-07-01

      Long-lived radioactive nuclei play an important role as nucleo-cosmochronometers and as cosmic tracers of nucleosynthetic source activity. In particular, nuclei in the actinide region like thorium, uranium, and plutonium can testify to the enrichment of an environment by the still enigmatic astrophysical sources that are responsible for the production of neutron-rich nuclei by the rapid neutron-capture process (r-process). Supernovae and merging neutron-star (NS) or NS-black hole binaries are considered as most likely sources of the r-nuclei. But arguments in favour of one or the other or both are indirect and make use of assumptions; they are based on theoretical models with remaining simplifications and shortcomings. An unambiguous observational determination of a production event is still missing. In order to facilitate searches in this direction, e.g. by looking for radioactive tracers in stellar envelopes, the interstellar medium or terrestrial reservoirs, we provide improved theoretical estimates and corresponding uncertainty ranges for the actinide production (232Th, 235, 236, 238U, 237Np, 244Pu, and 247Cm) in neutrino-driven winds of core-collapse supernovae. Since state-of-the-art supernova models do not yield r-process viable conditions - but still lack, for example, the effects of strong magnetic fields - we base our investigation on a simple analytical, Newtonian, adiabatic and steady-state wind model and consider the superposition of a large number of contributing components, whose nucleosynthesis-relevant parameters (mass weight, entropy, expansion time-scale, and neutron excess) are constrained by the assumption that the integrated wind nucleosynthesis closely reproduces the Solar system distribution of r-process elements. We also test the influence of uncertain nuclear physics.

    1. Solar r-process-constrained actinide production in neutrino-driven winds of supernovae

      NASA Astrophysics Data System (ADS)

      Goriely, S.; Janka, H.-Th.

      2016-04-01

      Long-lived radioactive nuclei play an important role as nucleo-cosmochronometers and as cosmic tracers of nucleosynthetic source activity. In particular nuclei in the actinide region like thorium, uranium, and plutonium can testify to the enrichment of an environment by the still enigmatic astrophysical sources that are responsible for the production of neutron-rich nuclei by the rapid neutron-capture process (r-process). Supernovae and merging neutron-star (NS) or NS-black hole binaries are considered as most likely sources of the r-nuclei. But arguments in favour of one or the other or both are indirect and make use of assumptions; they are based on theoretical models with remaining simplifications and shortcomings. An unambiguous observational determination of a production event is still missing. In order to facilitate searches in this direction, e.g. by looking for radioactive tracers in stellar envelopes, the interstellar medium or terrestrial reservoirs, we provide improved theoretical estimates and corresponding uncertainty ranges for the actinide production (232Th, 235, 236, 238U, 237Np, 244Pu, and 247Cm) in neutrino-driven winds of core-collapse supernovae. Since state-of-the-art supernova models do not yield r-process viable conditions -but still lack, for example, the effects of strong magnetic fields- we base our investigation on a simple analytical, Newtonian, adiabatic and steady-state wind model and consider the superposition of a large number of contributing components, whose nucleosynthesis-relevant parameters (mass weight, entropy, expansion time scale, and neutron excess) are constrained by the assumption that the integrated wind nucleosynthesis closely reproduces the solar system distribution of r-process elements. We also test the influence of uncertain nuclear physics.

    2. The r-process in Proto-neutron-star Wind Revisited

      NASA Astrophysics Data System (ADS)

      Wanajo, Shinya

      2013-06-01

      We examine the r-process in the neutrino-driven proto-neutron-star (PNS) wind of core-collapse supernovae in light of the recent findings of massive neutron stars in binaries as well as of an indication of neutron-richness in the PNS ejecta because of the nucleon potential corrections on neutrino opacities. To this end, a spherically symmetric, general relativistic, steady-state wind model is applied for a wide range of PNS masses between 1.2 M ⊙ and 2.4 M ⊙ with the latter reaching the causality limit. Nucleosynthesis calculations with these PNS models are performed by assuming a time evolution of electron fraction with its minimal value of Y e = 0.4, which mimics recent hydrodynamical results. The fundamental nucleosynthetic aspect of the PNS wind is found to be the production of Sr, Y, and Zr in quasi-equilibrium and of the elements with A ≈ 90-110 by a weak r-process, which can be an explanation for the abundance signatures in r-process-poor Galactic halo stars. PNSs more massive than 2.0 M ⊙ can eject heavy r-process elements, however, with substantially smaller amount than what is needed to account for the solar content. PNS winds can be thus the major origin of light trans-iron elements but no more than 10% of those heavier than A ~ 110, although they may be the sources of the low-level abundances of Sr and Ba found in numerous metal-poor stars if the maximum mass of PNSs exceeds 2.0 M ⊙.

    3. 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/).

    4. 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.

    5. Exploiting pre-rRNA processing in Diamond Blackfan anemia gene discovery and diagnosis.

      PubMed

      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

      2014-10-01

      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

    6. Collective flavor oscillations of supernova neutrinos and r-process nucleosynthesis

      SciTech Connect

      Chakraborty, Sovan; Kar, Kamales; Goswami, Srubabati E-mail: sandhya@hri.res.in E-mail: kamales.kar@saha.ac.in

      2010-06-01

      Neutrino-neutrino interactions inside core-collapse supernovae may give rise to collective flavor oscillations resulting in swap between flavors. These oscillations depend on the initial energy spectra, and relative fluxes or relative luminosities of the neutrinos. It has been observed that departure from energy equipartition among different flavors can give rise to one or more sharp spectral swap over energy, termed as splits. We study the occurrence of splits in the neutrino and antineutrino spectra, varying the initial relative fluxes for different models of initial energy spectrum, in both normal and inverted hierarchy. These initial relative flux variations give rise to several possible split patterns whereas variation over different models of energy spectra give similar results. We explore the effect of these spectral splits on the electron fraction, Y{sub e}, that governs r-process nucleosynthesis inside supernovae. Since spectral splits modify the electron neutrino and antineutrino spectra in the region where r-process is postulated to happen, and since the pattern of spectral splits depends on the initial conditions of the spectra and the neutrino mass hierarchy, we show that the condition Y{sub e} < 0.5 required for successful r-process nucleosynthesis will lead to constraints on the initial spectral conditions, for a given neutrino mass hierarchy.

    7. Neutrino-Induced Charged-Current Reaction Rates for r-PROCESS Nuclei

      NASA Astrophysics Data System (ADS)

      Langanke, K.; Kolbe, E.

      2001-11-01

      Neutrino-induced reactions play an important role during and after the r-process if it occurs in an environment with extreme neutrino fluxes, as in the neutrino-driven wind model or neutron star mergers. The neutrino reactions can excite the daughter nucleus above the neutron threshold, which is quite low for r-process nuclei. Thus the daughter nucleus will decay by emission of one or several neutrons. We have calculated the relevant total (νe, e-) cross sections as well as the partial neutron spallation cross sections for r-process nuclei with neutron numbers N=41-135 and proton numbers Z=21-82. The supernova neutrino spectrum is described by a Fermi-Dirac distribution with various temperature parameters between T=2.8 MeV and T=10 MeV and with the degeneracy parameters α=0 and α=3. Our calculations of the nuclear response are based on the random phase approximation and consider allowed as well as forbidden transitions.

    8. a Review of r-PROCESS Nucleosynthesis in the Collapsar Jet

      NASA Astrophysics Data System (ADS)

      Nakamura, Ko; Kajino, Toshitaka; Mathews, Grant J.; Sato, Susumu; Harikae, Seiji

      2013-10-01

      The collapsar scenario for long-duration gamma ray bursts (GRBs) has been proposed as a possible astrophysical site for r-process nucleosynthesis. We summarize the status of r-process nucleosynthesis calculations of our group and others in the context of a magnetohydrodynamics + neutrino-heated collapsar model. In the simulations of our group, we begin with a relativistic magnetohydrodynamic model including 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 associated jet was then followed using axisymmetric special relativistic hydrodynamics. We utilized representative test particles to follow the temperature, entropy, electron fraction and density for material flowing within the jet from ejection from the accretion disk until several thousand kilometer above the black hole as temperatures fall from 9×109 to 3×108 K. The evolution of nuclear abundances from nucleons to heavy nuclei for ejected test particle trajectories has been solved in a large nuclear reaction network. It was found that an r-process-like abundance distribution forms in material ejected in the collapsar jet.

    9. Analysis of launch site processing effectiveness for the Space Shuttle 26R payload

      NASA Technical Reports Server (NTRS)

      Flores, Carlos A.; Heuser, Robert E.; Pepper, Richard E., Jr.; Smith, Anthony M.

      1991-01-01

      A trend analysis study has been performed on problem reports recorded during the Space Shuttle 26R payload's processing cycle at NASA-Kennedy, using the defect-flow analysis (DFA) methodology; DFA gives attention to the characteristics of the problem-report 'population' as a whole. It is established that the problem reports contain data which distract from pressing problems, and that fully 60 percent of such reports were caused during processing at NASA-Kennedy. The second major cause of problem reports was design defects.

    10. Elucidating the role of C/D snoRNA in rRNA processing and modification in Trypanosoma brucei.

      PubMed

      Barth, Sarit; Shalem, Boaz; Hury, Avraham; Tkacz, Itai Dov; Liang, Xue-Hai; Uliel, Shai; Myslyuk, Inna; Doniger, Tirza; Salmon-Divon, Mali; Unger, Ron; Michaeli, Shulamit

      2008-01-01

      Most eukaryotic C/D small nucleolar RNAs (snoRNAs) guide 2'-O methylation (Nm) on rRNA and are also involved in rRNA processing. The four core proteins that bind C/D snoRNA in Trypanosoma brucei are fibrillarin (NOP1), NOP56, NOP58, and SNU13. Silencing of NOP1 by RNA interference identified rRNA-processing and modification defects that caused lethality. Systematic mapping of 2'-O-methyls on rRNA revealed the existence of hypermethylation at certain positions of the rRNA in the bloodstream form of the parasites, suggesting that this modification may assist the parasites in coping with the major temperature changes during cycling between their insect and mammalian hosts. The rRNA-processing defects of NOP1-depleted cells suggest the involvement of C/D snoRNA in trypanosome-specific rRNA-processing events to generate the small rRNA fragments. MRP RNA, which is involved in rRNA processing, was identified in this study in one of the snoRNA gene clusters, suggesting that trypanosomes utilize a combination of unique C/D snoRNAs and conserved snoRNAs for rRNA processing. PMID:17981991

    11. 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.

    12. Impact of pnpR, a LysR-type regulator-encoding gene, on the cellular processes of Pseudomonas putida DLL-E4.

      PubMed

      Chen, Qiongzhen; Tu, Hui; Huang, Fei; Wang, Yicheng; Dong, Weiliang; Wang, Wenhui; Li, Zhoukun; Wang, Fei; Cui, Zhongli

      2016-06-01

      LysR-type transcriptional regulators (LTTRs) regulate various cellular processes in bacteria. pnpR is an LTTR-encoding gene involved in the regulation of hydroquinone (HQ) degradation, and its effects on the cellular processes of Pseudomonas putida DLL-E4 were investigated at the physiological, biochemical and molecular levels. Reverse transcription polymerase chain reaction revealed that pnpR positively regulated its own expression and that of the pnpC1C2DECX1X2 operon; additionally, pnpR partially regulated the expression of pnpA when P. putida was grown on para-nitrophenol (PNP) or HQ. Strains DLL-E4 and DLL-ΔpnpR exhibited similar cellular morphologies and growth rates. Transcriptome analysis revealed that pnpR regulated the expression of genes in addition to those involved in PNP degradation. A total of 20 genes were upregulated and 19 genes were downregulated by at least 2-fold in strain DLL-ΔpnpR relative to strain DLL-E4. Bioinformatic analysis revealed putative PnpR-binding sites located in the upstream regions of genes involved in PNP degradation, carbon catabolite repression and other cellular processes. The utilization of L-aspartic acid, L-histidine, L-pyroglutamic acid, L-serine, γ-aminobutyric acid, D,L-lactic acid, D-saccharic acid, succinic acid and L-alaninamide was increased at least 1.3-fold in strain DLL-ΔpnpR as shown by BIOLOG assays, indicating that pnpR plays a potential negative regulation role in the utilization of carbon sources. PMID:27190157

    13. Origins of light trans-Fe and r-process elements deduced from Galactic chemical evolution

      NASA Astrophysics Data System (ADS)

      Ishimaru, Yuhri; Arao, Sachie; Wanajo, Shinya; Prantzos, Nicolas

      2014-09-01

      Compact binary mergers are suggested to be the major site of the r-process elements 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 large scatters in r-process elements of very metal-poor stars (MPS). 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 clusterings of sub-halos. We find that star-to-star scatters of [r/Fe] in MPS can be well explained with this scenario. Observations of MPS also show large enhancement of Sr relative to Ba, suggesting a distinct site of light trans-Fe elements. Recent nucleosynthesis studies show that electron-capture supernovae (ECSNe) can produce heavy elements up to Zr (Wanajo et al. 2011). Using our inhomogeneous chemical evolution model, we discuss that ECSNe can explain observed enhancement of Zn in MPS as well as of Sr, Y, and Zr.

    14. Sequences implicated in the processing of Thermus thermophilus HB8 23S rRNA.

      PubMed Central

      Hartmann, R K; Ulbrich, N; Erdmann, V A

      1987-01-01

      Nuclease S1 mapping analyses were performed in order to detect processing intermediates of pre-23S rRNA from Thermus thermophilus HB8. Two processing sites were identified downstream the start of transcription and several consecutive cleavage sites are associated with the mature 5'-end. In the 3'-flanking region one "primary" site and two cleavages which generate short-living intermediates were detected. A series of successive intermediates in the region of the mature 3'-end implies the existence of--in analogy to Escherichia coli--a 3'-exonucleolytic activity. The data were correlated with potential secondary structures within the pre-23S rRNA, which exhibit various repeated sequence elements. M13 sequencing data support the existence of one secondary structural element associated with the strong "primary" cleavage site in the 3'-flanking region. In T. thermophilus we can exclude the formation of an extended base-paired and precursor-specific stem enclosing the 23S rRNA which is inferred to mediate recognition by RNase III in E. coli. Images PMID:3313273

    15. Handing over the baton: connecting medicinal chemistry with process R&D.

      PubMed

      Federsel, Hans-Jurgen

      2008-05-01

      The pharmaceutical industry, as virtually any other industry, is continuously striving to become more effective and efficient. This demand for improving business processes is focused on all parts of the organization-from R&D and manufacturing to marketing and sales. Specifically from an R&D perspective, there are two areas that stand out as having caught more attention than others: attrition and timelines. While the former, so far, has seen relatively small changes for the better, the latter has reached clear targets in reducing the overall time required for the various activities conducted during drug discovery and development phases. For process R&D-the unit accountable for the design and optimization of small-molecule synthetic routes as well as delivery of active substance (API) for clinical and toxicological testing-the key contribution in this respect has been the shortening of lead times for supply of the first batch of material on scale. Thus, applying a work model based on balanced frontloading has shown that this crucial task can be taken off the critical path, and instead of delivering required API amounts several months post candidate drug nomination, the availability can now be guaranteed at or even ahead of reaching this milestone. The paradigm shift that has been necessary in order to reach this goal is the subject of this article. PMID:18560618

    16. 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.

    17. 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

    18. Enabling Web-Based Analysis of CUAHSI HIS Hydrologic Data Using R and Web Processing Services

      NASA Astrophysics Data System (ADS)

      Ames, D. P.; Kadlec, J.; Bayles, M.; Seul, M.; Hooper, R. P.; Cummings, B.

      2015-12-01

      The CUAHSI Hydrologic Information System (CUAHSI HIS) provides open access to a large number of hydrological time series observation and modeled data from many parts of the world. Several software tools have been designed to simplify searching and access to the CUAHSI HIS datasets. These software tools include: Desktop client software (HydroDesktop, HydroExcel), developer libraries (WaterML R Package, OWSLib, ulmo), and the new interactive search website, http://data.cuahsi.org. An issue with using the time series data from CUAHSI HIS for further analysis by hydrologists (for example for verification of hydrological and snowpack models) is the large heterogeneity of the time series data. The time series may be regular or irregular, contain missing data, have different time support, and be recorded in different units. R is a widely used computational environment for statistical analysis of time series and spatio-temporal data that can be used to assess fitness and perform scientific analyses on observation data. R includes the ability to record a data analysis in the form of a reusable script. The R script together with the input time series dataset can be shared with other users, making the analysis more reproducible. The major goal of this study is to examine the use of R as a Web Processing Service for transforming time series data from the CUAHSI HIS and sharing the results on the Internet within HydroShare. HydroShare is an online data repository and social network for sharing large hydrological data sets such as time series, raster datasets, and multi-dimensional data. It can be used as a permanent cloud storage space for saving the time series analysis results. We examine the issues associated with running R scripts online: including code validation, saving of outputs, reporting progress, and provenance management. An explicit goal is that the script which is run locally should produce exactly the same results as the script run on the Internet. Our design can

    19. r-PROCESS Nucleosynthesis in Type-II Supernova Model with Neutron Star Mass ~ 1.4M⊙

      NASA Astrophysics Data System (ADS)

      Terasawa, Mariko

      2002-09-01

      It is generally believed that the r-process occurs under explosive conditions at high neutron density, high temperature, and high entropy. It has been discussed, for sometime, that core-collapse supernovae could provide the most likely environment for such r-process nucleosynthesis. So far, the models of neutrino-driven winds from very massive (M≥ 1.7M⊙) and compact neutron star have proved to get successful r-process abundance pattern. A short expansion time is required to obtain a high neutron-to-seed ratio at moderate entropy. This expansion time is obtained by adopting a high neutron star gravitational mass, M~ 2M⊙, and a neutron star radius of R~ 10 km. However, such a large mass is sometimes criticized from observational viewpoints although several established EOSs for neutron star matter are known to stabilize massive core as far as M≤ 2.2M⊙. Nucleosynthesis in the r-process is strongly dependent on the gravitational mass of the proto-neutron star, and for this reason it is taken to be an adjustable parameter to give good r-process yields. In this paper, we study the effects of the outer boundary conditions of neutrino-driven winds on the r-process nucleosynthesis. We can get a reasonable agreement with the solar system r-process abundance pattern even by adopting the 'standard' 1.4M⊙ mass model for the proto-neutron star.

    20. Beta-delayed neutron emission measurements for r-process nuclei

      NASA Astrophysics Data System (ADS)

      Dillmann, Iris

      2014-09-01

      Beta-delayed neutron- (bn-) emitters play an important, two-fold role in the stellar nucleosynthesis of heavy elements in the ``rapid neutron-capture process'' (r process). On one hand they lead to a detour of the material beta-decaying back to stability. On the other hand, the released neutrons increase the neutron-to-seed ratio, and are re-captured during the freeze-out phase and thus influence the final solar r-abundance curve. A large fraction of the isotopes for r-process nucleosynthesis are not yet experimentally accessible and are located in the ``terra incognita.'' With the next generation of fragmentation and ISOL facilities presently being built or already in operation, one of the main motivation of all projects is the investigation of very neutron-rich isotopes at and beyond the border of presently known nuclei. However, reaching more neutron-rich isotopes means also that multiple neutron-emission becomes the dominant decay mechanism. The investigation of bn-emitters has recently experienced a renaissance. I will show some recent results from a GSI campaign with the BELEN detector, and introduce the program planned for 2015/16 at RIKEN with the ``BRIKEN'' detector. ``BRIKEN'' (``Beta-delayed neutron measurements at RIKEN for nuclear structure, astrophysics, and applications'') is a worldwide effort which combines 3He-neutron counters from groups in Germany, Japan, Russia, Spain, and the USA and the implantation detector AIDA from the UK to the presently largest and most efficient neutron detection setup. Planned first experiments comprise the first-time measurements of 48 b-delayed one-neutron and 24 b-delayed two-neutron emitters in the regions around doubly-magic 78Ni and 132Sn. Even some b-delayed three-neutron emitters in the heavier mass region will be tackled for the first time.

    1. 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.

    2. Novel technique for constraining r-process (n, γ) reaction rates.

      PubMed

      Spyrou, A; Liddick, S N; Larsen, A C; Guttormsen, M; Cooper, K; Dombos, A C; Morrissey, D J; Naqvi, F; Perdikakis, G; Quinn, S J; Renstrøm, T; Rodriguez, J A; Simon, A; Sumithrarachchi, C S; Zegers, R G T

      2014-12-01

      A novel technique has been developed, which will open exciting new opportunities for studying the very neutron-rich nuclei involved in the r process. As a proof of principle, the γ spectra from the β decay of ^{76}Ga have been measured with the SuN detector at the National Superconducting Cyclotron Laboratory. The nuclear level density and γ-ray strength function are extracted and used as input to Hauser-Feshbach calculations. The present technique is shown to strongly constrain the ^{75}Ge(n,γ)^{76}Ge cross section and reaction rate. PMID:25526121

    3. 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.

    4. 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.

    5. 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

      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

    6. Mass Measurements beyond the Major r-Process Waiting Point {sup 80}Zn

      SciTech Connect

      Baruah, S.; Herlert, A.; Schweikhard, L.; Audi, G.; Guenaut, C.; Lunney, D.; Blaum, K.; George, S.; Dworschak, M.; Herfurth, F.; Yazidjian, C.; Hager, U.; Kellerbauer, A.; Kluge, H.-J.; Schatz, H.

      2008-12-31

      High-precision mass measurements on neutron-rich zinc isotopes {sup 71m,72-81}Zn have been performed with the Penning trap mass spectrometer ISOLTRAP. For the first time, the mass of {sup 81}Zn has been experimentally determined. This makes {sup 80}Zn the first of the few major waiting points along the path of the astrophysical rapid neutron-capture process where neutron-separation energy and neutron-capture Q-value are determined experimentally. The astrophysical conditions required for this waiting point and its associated abundance signatures to occur in r-process models can now be mapped precisely. The measurements also confirm the robustness of the N=50 shell closure for Z=30.

    7. 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

    8. The structure of the ITS2-proximal stem is required for pre-rRNA processing in yeast.

      PubMed Central

      Peculis, B A; Greer, C L

      1998-01-01

      Accurate and efficient processing of pre-rRNA is critical to the accumulation of mature functional ribosomal subunits for maintenance of cell growth. Processing requires numerous factors which act in trans as well as RNA sequence/ structural elements which function in cis. To examine the latter, we have used directed mutagenesis and expression of mutated pre-rRNAs in yeast. Specifically, we tested requirements for formation of an ITS2-proximal stem on processing, a structure formed by an interaction between sequences corresponding to the 3' end of 5.8S rRNA and the 5' end of 25S. Pre-rRNA processing is inhibited in templates encoding mutations that prevent the formation of the ITS2-proximal stem. Compensatory, double mutations, which alter the sequence of this region but restore the structure of the stem, also restore processing, although at lower efficiency. This reduction in efficiency is reflected in decreased levels of mature 5.8S and 25S rRNA and increased levels of 35S pre-rRNA and certain processing intermediates. This phenotype is reminiscent of the biochemical depletion of U8 snoRNA in vertebrates for which the ITS2-proximal stem has been proposed as a potential site for interaction with U8 RNP. Thus, formation of the ITS2-proximal stem may be a requirement common to yeast and vertebrate pre-rRNA processing. PMID:9848657

    9. Beta-delayed fission probabilities of transfermium nuclei, involved in the r-process

      NASA Astrophysics Data System (ADS)

      Panov, I.; Lutostansky, Yu; Thielemann, F.-K.

      2016-01-01

      For the nucleosynthesis of heavy and superheavy nuclei fission becomes very important when the r-process runs in a very high neutron density environment. In part, fission is responsible for the formation of heavy nuclei due to the inclusion of fission products as new seed nuclei (fission cycling). More than that, beta-delayed fission, along with spontaneous fission, is responsible in the late stages of the r-process for the suppression of superheavy element yields. For beta-delayed fission probability calculations a model description of the beta-strength- functions is required. Extended theoretical predictions for astro-physical applications were provided long ago, and new predictions also for superheavy nuclei with uptodate nuclear input are needed. For the further extension of data to heavier transactinides the models of strength- functions should be modified, taking into account more complicated level schemes. In our present calculations the strength-function model is based on the quasi-particle approximation of Finite Fermi Systems Theory. The probabilities of beta-delayed fission and beta-delayed neutron emission are calculated for some transfermium neutron-rich nuclei, and the influence of beta-delayed fission upon superheavy element formation is discussed.

    10. The Most Complete Template for r-process Nucleosynthesis beyond the Solar System

      NASA Astrophysics Data System (ADS)

      Roederer, Ian

      2012-10-01

      We propose to observe two metal-poor stars that present a unique opportunity to expand the chemical inventory to unprecedented levels in an environment beyond the solar system. The proposed observations will allow us to detect several key elements, including arsenic {As, Z=33} and selenium {Se, Z=34}, that cannot be detected from the ground. These elements are key to understanding the nature of the r-process in the first generations of stars that drive chemical evolution of the Galaxy, yet their abundance in the one star where they have been detected is not fully explained by current models. We will use STIS to obtain high-resolution UV spectra from 1900 to 2380 Angstroms in two metal-poor stars enriched with modest but differing amounts of r-process material, HD 108317 and HD 128279. We will perform an abundance analysis and derive abundances or meaningful upper limits for the heavy elements Cu, Zn, Ge, As, Se, Zr, Mo, Cd, Te, Yb, Os, Ir, Pt, and Pb. This work is supported by recent laboratory experiments and theoretical studies that continue to provide data of wider interest to the atomic, nuclear, and astrophysics communities.

    11. 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 τ. We find that the ejecta is lanthanide-free for Ye >~ 0 . 22 - 0 . 3 , depending on s and τ. The heating rate is insensitive to s and τ, 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.

    12. 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 γ-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.

    13. SIRT7-dependent deacetylation of the U3-55k protein controls pre-rRNA processing

      PubMed Central

      Chen, Sifan; Blank, Maximilian Felix; Iyer, Aishwarya; Huang, Bingding; Wang, Lin; Grummt, Ingrid; Voit, Renate

      2016-01-01

      SIRT7 is an NAD+-dependent protein deacetylase with important roles in ribosome biogenesis and cell proliferation. Previous studies have established that SIRT7 is associated with RNA polymerase I, interacts with pre-ribosomal RNA (rRNA) and promotes rRNA synthesis. Here we show that SIRT7 is also associated with small nucleolar RNP (snoRNPs) that are involved in pre-rRNA processing and rRNA maturation. Knockdown of SIRT7 impairs U3 snoRNA dependent early cleavage steps that are necessary for generation of 18S rRNA. Mechanistically, SIRT7 deacetylates U3-55k, a core component of the U3 snoRNP complex, and reversible acetylation of U3-55k modulates the association of U3-55k with U3 snoRNA. Deacetylation by SIRT7 enhances U3-55k binding to U3 snoRNA, which is a prerequisite for pre-rRNA processing. Under stress conditions, SIRT7 is released from nucleoli, leading to hyperacetylation of U3-55k and attenuation of pre-rRNA processing. The results reveal a multifaceted role of SIRT7 in ribosome biogenesis, regulating both transcription and processing of rRNA. PMID:26867678

    14. Erbium And The r-Process In The Sun And Metal-poor Stars

      NASA Astrophysics Data System (ADS)

      Lawler, James; Sneden, C.; Cowan, J. J.

      2007-12-01

      Recent laboratory radiative lifetimes accurate to 5% for 8 even-parity and 72 odd-parity levels of Er II (Stockett et al. 2007, J. Phys. B, in press) were combined with emission branching fractions from Fourier transform spectra to determine accurate absolute transition probabilities for 418 lines of Er II. The lines span the UV to IR wavelength range from 289.2 to 1984.1 nm. Our gf-values have been applied to refine the solar photospheric erbium abundance and to determine erbium abundances in 4 metal-poor giant stars with enhanced r-process abundances (those with [Fe/H] < -2, [Eu/Fe] > +0.5). For the Sun we derive log ɛ(Er) = 0.96 ± 0.02 (σ = 0.06 from 8 lines). This value is in excellent agreement with Lodders' (2003, ApJ, 591, 1220) recommended meteoritic abundance: log ɛ(Er) = 0.95 ± 0.03. Combining the new photospheric Er abundance with our earlier study of Eu (log ɛ(Er) = 0.52 ± 0.01; Lawler et al. 2001, ApJ, 563, 1075) yields log ɛ(Er/Eu) = 0.43 for the Sun. The origin of both Er and Eu are attributed predominantly to production in rapid neutron-capture synthesis (the r-process) in solar-system material, 83% and 97% respectively (Simmerer et al. 2004, ApJ, 617, 1091). We therefore applied the new transition data to the spectra of very metal-poor, r-process rich stars CS 22892-052, BD+17 3248, HD 115444, and HD 221170. Between 14 and 21 Er II features were usable in our abundance analyses in these stars. We derived = 0.43 for the four stars, obviously in excellent agreements with the solar value. This work has been supported by the National Science Foundations through grants AST-0506324 to JEL, AST-0607708 to CS, and AST-0707447 to JJC.

    15. On the dynamics of proto-neutron star winds and r-process nucleosynthesis

      NASA Astrophysics Data System (ADS)

      Panov, I. V.; Janka, H.-Th.

      2009-02-01

      We study here the formation of heavy r-process nuclei in the high-entropy environment of rapidly expanding neutrino-driven winds from compact objects. In particular, we explore the sensitivity of the element creation in the A ⪆ 130 region to the low-temperature behavior of the outflows. For this purpose we employ a simplified model of the dynamics and of the thermodynamical evolution for radiation dominated, adiabatic outflows. It consists of a first stage of fast, exponential cooling with timescale τ_dyn, followed by a second phase of slower evolution, assuming either constant density and temperature or a power-law decay of these quantities. These cases describe a strong deceleration or decreasing acceleration of the transsonic outflows, respectively, and thus are supposed to capture the most relevant effects associated with a change in the wind expansion behavior at large radii, for example because of the collision with the slower, preceding supernova ejecta and the possible presence of a wind termination shock. We find that for given entropy, expansion timescale, and proton-to-baryon ratio not only the transition temperature between the two expansion phases can make a big difference in the formation of the platinum peak, but also the detailed cooling law during the later phase. Because the nuclear photodisintegration rates between about 2× 108 K and roughly 109 K are more sensitive to the temperature than the neutron-capture rates are to the free neutron density, a faster cooling but continuing high neutron density in this temperature regime allow the r-process path to move closer to the neutron-drip line. With low (γ,n)- but high β-decay rates, the r-processing does then not proceed through a (γ, n)-(n, γ) equilibrium but through a quasi-equilibrium of (n, γ)-reactions and β-decays, as recently also pointed out by Wanajo. Unless the transition temperature and corresponding (free neutron) density become too low (T ⪉ 2× 108 K), a lower temperature or

    16. Process R&D under the magnifying glass: organization, business model, challenges, and scientific context.

      PubMed

      Federsel, Hans-Jürgen

      2010-08-15

      Initially, the aim is to provide the big picture illustrating the as is situation in the pharmaceutical industry: a lack of productivity resulting in too few products reaching the market; a loss of billions in revenue over the next few years as some of the major megabrands go off patent; a spiraling cost for developing new drugs and taking them through clinical and safety studies. Following on, a look deeper into the organization will offer an insight into the state-of-the-art in a technical function accountable for chemical Process R&D (with a remit to develop scalable, robust, and cost efficient processes for small molecules). The vast majority of compounds already launched in the form of drug products on the market or still being pursued through the phases of discovery and development, fall within the category of small molecules (as opposed to biopharmaceuticals, e.g., proteins, monoclonal antibodies). This typically means molecular weights of <1000Da and puts organic synthesis in the widest sense of the word at the forefront of technologies needed to support R&D programs in the pharma industry. Understandably, the demands on Medicinal Chemistry are quite different to what applies in a Process R&D (PR&D) organization. In the former, making large numbers of potentially interesting molecules, many of which are discarded after testing, is a key driver and for this virtually any synthetic methodology will suffice. For PR&D, however, homing in on selected compounds there is an expectation that the best synthetic routes will be delivered that meet a number of tough criteria, for instance from an environmental and safety point of view, allowing operation on large scale, offering cost competitiveness, avoiding patent infringements, showing sustainability for long-term production, etc. The intention is to focus on issues to be addressed during this transition by providing examples of changes that had to be put in place in order to make the supply of larger amounts of

    17. Production of the entire range of r-process nuclides by black hole accretion disk outflows from neutron star mergers

      NASA Astrophysics Data System (ADS)

      Wu, Meng-Ru; Fernández, Rodrigo; Martínez-Pinedo, Gabriel; Metzger, Brian D.

      2016-08-01

      We consider r-process nucleosynthesis in outflows from black hole accretion disks formed in double neutron star and neutron star - black hole mergers. These outflows, powered by angular momentum transport processes and nuclear recombination, represent an important - and in some cases dominant - contribution to the total mass ejected by the merger. Here we calculate the nucleosynthesis yields from disk outflows using thermodynamic trajectories from hydrodynamic simulations, coupled to a nuclear reaction network. We find that outflows produce a robust abundance pattern around the second r-process peak (mass number A ˜ 130), independent of model parameters, with significant production of A < 130 nuclei. This implies that dynamical ejecta with high electron fraction may not be required to explain the observed abundances of r-process elements in metal poor stars. Disk outflows reach the third peak (A ˜ 195) in most of our simulations, although the amounts produced depend sensitively on the disk viscosity, initial mass or entropy of the torus, and nuclear physics inputs. Some of our models produce an abundance spike at A = 132 that is absent in the Solar System r-process distribution. The spike arises from convection in the disk and depends on the treatment of nuclear heating in the simulations. We conclude that disk outflows provide an important - and perhaps dominant - contribution to the r-process yields of compact binary mergers, and hence must be included when assessing the contribution of these systems to the inventory of r-process elements in the Galaxy.

    18. 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.

    19. 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.

    20. β-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 β-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 β-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%.

    1. 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.

    2. Submicron sized R2 Fe14 B particles fabricated by mechanochemical process

      NASA Astrophysics Data System (ADS)

      Koylu-Alkan, Ozlem; Barandiaran, Jose Manuel; Salazar, Daniel; Hadjipanayis, George C.; Univ. of Delaware Team; Univ. Basque Country Team

      In this work, we have synthesized submicron R2Fe14B particles by the mechanochemical process. Mechanical activation of oxides of rare earth, iron and boron was done by high energy ball milling in a CaO with a reduction agent (Ca). After a heat treatment at 900 °C the powder was washed with water and glycerol solution to remove the dispersant and other non-magnetic phases. Magnetic measurements showed that the as-synthesized unwashed powders had coercivity values of 10.3 kOe, 12.8 kOe, and 24.6 kOe for R =Nd, Pr, and Dy, respectively. During washing, H2 is released and absorbed by the 2:14:1 structure. After removing the H2, the submicron particles have coercivities of 3.3 kOe (Nd), 4.4 kOe (Pr) and 21.0 kOe (Dy) with average sizes 160 nm, 242 nm, and 107 nm, respectively. Fitting of high field M(H) measurements to the law of approach to saturation showed that the anisotropy constant of the Nd2Fe14B particles are 3.73x107 erg/cm3 which is comparable to bulk. Work supported by DOE DE-FG02-04ERU4612 and Bizkaia Talent AYD-000-195. DOE DE-FG02-04ERU4612.

    3. β-decay spectroscopy of r-process nuclei with N = 126 at KISS

      NASA Astrophysics Data System (ADS)

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

      2014-05-01

      The β-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 β-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. 136Xe projectile on 198Pt target). KISS will allow us to study unknown isotopes produced in weak reaction channels under low background conditions. We successfully extracted the stable 56Fe 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%.

    4. 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

    5. {sup 12}B(n,{gamma})--the influence on r-process nucleosynthesis of light elements

      SciTech Connect

      Lee, H. Y.; Jiang, C. L.; Pardo, R. C.; Rehm, K. E.; Schiffer, J. P.; Goodman, N. J.; Lighthall, J. C.; Marley, S. T.; Wuosmaa, A. H.; Notani, M.; Patel, N.; Tang, X.

      2009-03-04

      Because of interest in the {sup 11,12}B(n,{gamma}) reaction in seeding r-process nucleosynthesis through light neutron-rich nuclei, we have measured the {sup 12}B(d,p) reaction for the first time using the ATLAS in-flight facility at Argonne National Laboratory. We also measured the {sup 11}B(d,p) reaction in the same way for calibration. The spectroscopic factors of excited states and the branching ratio of the neutron-unbound state in {sup 12}B are obtained from the current experiment and the reaction rate for {sup 11}B(n,{gamma}) is discussed in comparison with the theoretical prediction.

    6. In search of sustainability: process R&D in light of current pharmaceutical industry challenges.

      PubMed

      Federsel, Hans-Jürgen

      2006-11-01

      Is there a need for a paradigm shift in the pharmaceutical industry? Many researchers think so and take as examples the eroding corporate reputation, a regulatory environment that is harsher than ever, and the request for cheaper drugs from patient organizations and authorities. Process R&D, which interfaces medicinal chemistry and production, has taken on this challenge by increasing the delivery focus early on to ensure timely availability of desired compounds. The quest for lower costs of goods has forced the design of best synthetic routes that, given the molecular complexity, often lead to catalytic methodologies. Applying these methodologies will enable not only the cost element, but also the increasingly important aspects of environmental friendliness, and atom and stage efficiency, to be addressed. PMID:17055405

    7. Nonstandard. gamma. gamma. r arrow l sup + l minus processes in relativistic heavy-ion collisions

      SciTech Connect

      Almeida, L.D.; Natale, A.A.; Novaes, S.F. ); Eboli, O.J.P. )

      1991-07-01

      We study lepton pair production in heavy-ion collisions with emphasis on nonstandard contributions to the QED subprocess {gamma}{gamma}{r arrow}{ital l}{sup +}{ital l{minus}}. The existence of compositeness of fermions and/or bosons can be tested in this reaction up to the TeV mass scale. We show that for some processes the capabilities of relativistic heavy-ion colliders to disclose new physics surpass the possibilities of {ital e}{sup +}{ital e{minus}} or {ital p{bar p}} machines. In particular, spin-zero composite particles which couple predominantly to two photons, predicted in composite models, can be studied in a broad range of masses.

    8. miR-24, miR-30b and miR-142-3p interfere with antigen processing and presentation by primary macrophages and dendritic cells

      PubMed Central

      Naqvi, Afsar Raza; Fordham, Jezrom B.; Ganesh, Balaji; Nares, Salvador

      2016-01-01

      Antigen uptake, processing and presentation by antigen presenting cells (APCs) are tightly coupled processes which consequently lead to the activation of innate and adaptive immune responses. However, the regulatory role of microRNA (miRNAs) in these critical pathways is poorly understood. In this study, we show that overexpression of miR-24, miR-30b and miR-142-3p attenuates uptake and processing of soluble antigen ovalbumin (Ova) in primary human macrophages and dendritic cells. MiRNA mimic transfected APCs exhibit defects in antigen presentation (Ova and CMV antigen) to CD4+ T-cells leading to reduced cell proliferation. Using transgenic OT-II mice we demonstrated that this impairment in T-cell proliferation is specific to antigen provided i.e., Ova. Further, human T-cells co-cultured with miRNA transfected dendritic cells secrete low levels of T helper (Th)-1 polarization associated cytokines. Analysis of molecules regulating APC and T-cell receptor interaction shows miRNA-mediated induced expression of Programmed Death-Ligand 1 (PD-L1) which inhibits T-cell proliferation. Blocking PD-L1 with antibodies rescues miRNA-mediated inhibition of T cell priming by DCs. These results uncover regulatory functions of miR-24, miR-30b and miR-142-3p in pairing innate and adaptive components of immunity. PMID:27611009

    9. miR-24, miR-30b and miR-142-3p interfere with antigen processing and presentation by primary macrophages and dendritic cells.

      PubMed

      Naqvi, Afsar Raza; Fordham, Jezrom B; Ganesh, Balaji; Nares, Salvador

      2016-01-01

      Antigen uptake, processing and presentation by antigen presenting cells (APCs) are tightly coupled processes which consequently lead to the activation of innate and adaptive immune responses. However, the regulatory role of microRNA (miRNAs) in these critical pathways is poorly understood. In this study, we show that overexpression of miR-24, miR-30b and miR-142-3p attenuates uptake and processing of soluble antigen ovalbumin (Ova) in primary human macrophages and dendritic cells. MiRNA mimic transfected APCs exhibit defects in antigen presentation (Ova and CMV antigen) to CD4+ T-cells leading to reduced cell proliferation. Using transgenic OT-II mice we demonstrated that this impairment in T-cell proliferation is specific to antigen provided i.e., Ova. Further, human T-cells co-cultured with miRNA transfected dendritic cells secrete low levels of T helper (Th)-1 polarization associated cytokines. Analysis of molecules regulating APC and T-cell receptor interaction shows miRNA-mediated induced expression of Programmed Death-Ligand 1 (PD-L1) which inhibits T-cell proliferation. Blocking PD-L1 with antibodies rescues miRNA-mediated inhibition of T cell priming by DCs. These results uncover regulatory functions of miR-24, miR-30b and miR-142-3p in pairing innate and adaptive components of immunity. PMID:27611009

    10. 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.

    11. 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.

    12. Containerless Processing in Reduced Gravity Using the TEMPUS Facility during MSL-1 and MSL-1R

      NASA Technical Reports Server (NTRS)

      Rogers, Jan R.

      1998-01-01

      Containerless processing provides a high purity environment for the study of high-temperature, very reactive materials. It is an important method which provides access to the metastable state of an undercooled melt. In the absence of container walls, the nucleation rate is greatly reduced and undercooling up to (Tm-Tn)/Tm approx. equal to 0.2 can be obtained, where Tm and Tn are the melting and nucleation temperatures, respectively. Electromagnetic levitation represents a method particularly well-suited for the study of metallic melts. The TEMPUS (Tiegelfreies ElektroMagnetisches Prozessieren Unter Schwerelosgkeit) facility is a research instrument designed to perform electromagnetic levitation studies in reduced gravity. TEMPUS is a joint undertaking between DARA, the German Space Agency, and the Microgravity Science and Applications Division of NASA. The George C. Marshall Space Flight Center provides the leadership for scientific and management efforts which support the four US PI teams which performed experiments in the TEMPUS facility. The facility is sensitive to accelerations in the 1-10 Hz range. This became evident during the MSL-1 mission. Analysis of accelerometer and video data indicated that loss of sample control occurred during crew exercise periods which created disturbances in this frequency range. Prior to the MSL-1R flight the TEMPUS team, the accelerometer support groups and the mission operations team developed a strategy to provide for the operation of the facility without such disturbances. The successful implementation of this plan led to the highly successful operation of this facility during MSL-1R.

    13. The integration of process R&D in drug discovery--challenges and opportunities.

      PubMed

      Federsel, Hans-Jürgen

      2006-02-01

      In today's situation where a lot of attention is put on the whereabouts of the pharmaceutical industry, especially focusing on productivity, pricing policies, time lines, and competition, there is an increased need for a critical revision of work practices in the business. The prevailing prioritization of time-to-market is now more and more shifting over to also put quality, risk management, and effectiveness/efficiency in the limelight. Resources in terms of people and money will continue to be constrained and, therefore, best collaborative principles have to be adopted between different parts of the organization. Only by operating this way will we maximize the output. One of the most important key performance indicators in pharma R&D is the number of newly appointed candidate drugs (CDs). However, it is not only a matter of counting numbers but, more so, to nominate compounds with the best properties and likelihood to survive. In that vein the demands on Process R&D have gone up considerably over recent years and there is now a pronounced need to make forecasts on cost of goods for the API (active pharmaceutical ingredient), scalability issues, IP matters, route design etc. On top of this, there is as always an expectation that the supply of material needed to conduct the various studies is timely, fully reliable, and flexible, even if volumes and delivery dates fluctuate widely. To successfully be able to cope with this challenging and sometimes stressful situation a back-integration into earlier parts of Drug Discovery is a must and, hence, connecting to new projects will have to be initiated already during the LO-stage (lead optimization). The consequences of this and its further implications will constitute the core part of the paper. PMID:16475965

    14. RNomics in Archaea reveals a further link between splicing of archaeal introns and rRNA processing

      PubMed Central

      Tang, Thean Hock; Rozhdestvensky, Timofey S.; d’Orval, Béatrice Clouet; Bortolin, Marie-Line; Huber, Harald; Charpentier, Bruno; Branlant, Christiane; Bachellerie, Jean-Pierre; Brosius, Jürgen; Hüttenhofer, Alexander

      2002-01-01

      The bulge–helix–bulge (BHB) motif recognised by the archaeal splicing endonuclease is also found in the long processing stems of archaeal rRNA precursors in which it is cleaved to generate pre-16S and pre-23S rRNAs. We show that in two species, Archaeoglobus fulgidus and Sulfolobus solfataricus, representatives from the two major archaeal kingdoms Euryarchaeota and Crenarchaeota, respectively, the pre-rRNA spacers cleaved at the BHB motifs surrounding pre-16S and pre-23S rRNAs subsequently become ligated. In addition, we present evidence that this is accompanied by circularisation of ribosomal pre-16S and pre-23S rRNAs in both species. These data reveal a further link between intron splicing and pre-rRNA processing in Archaea, which might reflect a common evolutionary origin of the two processes. One spliced RNA species designated 16S-D RNA, resulting from religation at the BHB motif of 16S pre-rRNA, is a highly abundant and stable RNA which folds into a three-stem structure interrupted by two single-stranded regions as assessed by chemical probing. It spans a region of the pre-rRNA 5′ external transcribed spacer exhibiting a highly conserved folding pattern in Archaea. Surprisingly, 16S-D RNA contains structural motifs found in archaeal C/D box small RNAs and binds to the L7Ae protein, a core component of archaeal C/D box RNPs. This supports the notion that it might have an important but still unknown role in pre-rRNA biogenesis or might even target RNA molecules other than rRNA. PMID:11842103

    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

      2016-08-01

      Neutron star mergers are one of the candidate astrophysical site(s) of r-process. Several chemical evolution studies however pointed out that the observed abundance of r-process is difficult to reproduce by neutron star mergers. In this study, we aim to clarify the enrichment of r-process elements in the Local Group dwarf galaxies. We carry out numerical simulations of galactic chemo-dynamical evolution using an N-body/smoothed particle hydrodynamics code, ASURA. We construct a chemo-dynamical evolution model for dwarf galaxies assuming that neutron star mergers are the major source of r-process elements. Our models reproduce the observed dispersion in [Eu/Fe] as a function of [Fe/H] with neutron star mergers with a merger time of 100 Myr. We find that star formation efficiency and metal mixing processes during the first <~ 300 Myr of galaxy evolution are important to reproduce the observations. This study supports that neutron star mergers are a major site of r-process.

    16. Chemo-dynamical evolution of the Local Group dwarf galaxies: The origin of r-process elements

      NASA Astrophysics Data System (ADS)

      Hirai, Y.; Ishimaru, Y.; Saitoh, T. R.; Fujii, M. S.; Hidaka, J.; Kajino, T.

      2016-06-01

      The r-process elements such as Au, Eu, and U are observed in the extremely metal-poor stars in the Milky Way halo and the Local Group dwarf galaxies. However, the origin of r-process elements has not yet been identified. The abundance of r-process elements of stars in the Local Group galaxies provides clues to clarify early evolutionary history of galaxies. It is important to understand the chemical evolution of the Local Group dwarf galaxies which would be building blocks of the Milky Way. In this study, we perform a series of N-body/smoothed particle hydrodynamic simulations of dwarf galaxies. We show that neutron star mergers can reproduce the observation of r-process elements. We find that the effects of gas mixing processes including metals in the star-forming region of a typical scale of giant molecular clouds ¥sim 10-100 pc play significant roles in the early chemical enrichment of dwarf galaxies. 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 these results. Our results suggest that neutron star mergers are a major site of r-process.

    17. COPASutils: an R package for reading, processing, and visualizing data from COPAS large-particle flow cytometers.

      PubMed

      Shimko, Tyler C; Andersen, Erik C

      2014-01-01

      The R package COPASutils provides a logical workflow for the reading, processing, and visualization of data obtained from the Union Biometrica Complex Object Parametric Analyzer and Sorter (COPAS) or the BioSorter large-particle flow cytometers. Data obtained from these powerful experimental platforms can be unwieldy, leading to difficulties in the ability to process and visualize the data using existing tools. Researchers studying small organisms, such as Caenorhabditis elegans, Anopheles gambiae, and Danio rerio, and using these devices will benefit from this streamlined and extensible R package. COPASutils offers a powerful suite of functions for the rapid processing and analysis of large high-throughput screening data sets. PMID:25329171

    18. HRIBF studies of r-process nuclei and first results with the new SuperORRUBA detector

      NASA Astrophysics Data System (ADS)

      Bardayan, D. W.; Ahn, S.; Blackmon, J. C.; Chae, K. Y.; Chipps, K. A.; Cizewski, J. A.; Hardy, S.; Howard, M. E.; Jones, K. L.; Kozub, R. L.; O'Malley, P. D.; Manning, B.; Matoš, M.; Nesaraja, C. D.; Pain, S. D.; Peters, W. A.; Pittman, S. T.; Ratkiewicz, A.; Schmitt, K. T.; Smith, M. S.; Spassova, I.; Strauss, S.

      2013-10-01

      The astrophysical rapid neutron-capture process (r-process) is believed to have produced approximately half of the nuclear species more massive than Fe. Unfortunately, almost nothing is known about the structure of the majority of the extremely neutron-rich nuclei involved in the reaction flow. At exotic beam facilities such as the Holifield Radioactive Ion Beam Facility (HRIBF), measurements with accelerated beams of fission fragments have provided some of the first spectroscopic information on many r-process nuclei. The new SuperORRUBA (Oak Ridge Rutgers University Barrel Array) detector has been constructed at the HRIBF to study such nuclei, and first results are presented.

    19. The Hamburg/ESO R-process Enhanced Star survey (HERES). VIII. The r+s star HE 1405-0822

      NASA Astrophysics Data System (ADS)

      Cui, W. Y.; Sivarani, T.; Christlieb, N.

      2013-10-01

      Aims: The aim of this study is a detailed abundance analysis of the newly discovered r-rich star HE 1405-0822, which has [Fe/H] = -2.40. This star shows enhancements of both r- and s-elements, [Ba/Fe] = + 1.95 and [Eu/Fe] = 1.54, for which reason it is called r+s star. Methods: Stellar parameters and element abundances were determined by analyzing high-quality VLT/UVES spectra. We used Fe I line excitation equilibria to derive the effective temperature. The surface gravity was calculated from the Fe i/Fe ii and Ti i/Ti ii equilibria. Results: We determined accurate abundances for 39 elements, including 19 neutron-capture elements. HE 1405-0822 is a red giant. Its strong enhancements of C, N, and s-elements are the consequence of enrichment by a former AGB companion with an initial mass of less than 3 M⊙. The heavy n-capture element abundances (including Eu, Yb, and Hf) seen in HE 1405-0822 do not agree with the r-process pattern seen in strongly r-process-enhanced stars. We discuss possible enrichment scenarios for this star. The enhanced α elements can be explained as the result of enrichment by supernovae of type II. Na and Mg may have partly been synthesized in a former AGB companion, when the primary 22Ne acted as a neutron poison in the 13C-pocket. Based on observations collected at the European Southern Observatory, Paranal, Chile (Proposal numbers 170.D-0010G, and 170.D-0010J).Tables 5, 6 are available in electronic form at http://www.aanda.org

    20. 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 β-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 νe-bar{ν }_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 νe luminosities and mean energies are relatively large compared to the bar{ν }_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.

    1. 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.

    2. Form analysis using digital signal processing reliably discriminates far-field R waves from P waves.

      PubMed

      Van Hemel, Norbert M; Wohlgemuth, Peter; Engbers, Jos G; Lawo, Thomas; Nebaznivy, Jan; Taborsky, Milos; Witte, Joachim; Boute, Wim; Munneke, Dave; Van Groeningen, Chris

      2004-12-01

      The correct detection of atrial arrhythmias by pacemakers is often limited by the presence of far-field R waves (FFRWs) in the atrial electrogram. Digital signal processing (DSP) of intracardiac signals is assumed to provide improved discrimination between P waves and FFRWs when compared to current methods. For this purpose, 100 bipolar and unipolar intracardiac atrial recordings from 31 patients were collected during pacemaker replacement and used for the off-line application of a novel DSP algorithm. Digital processing of the atrial intracardiac electrogram (IEGM) signals (8 bit, 800 samples/s) included filtering and calculation of the maximum amplitude and slope of the detected events. The form parameter was calculated, being the sum of the most negative value of the amplitude and that of the slope of the detected event. The algorithm collects form parameter data of P waves and FFRWs and composes histograms of these data. A sufficiently large gap between the FFRW and P wave histograms allows discrimination of these two signals based on form parameters. Three independent observers reviewed the reliability of classification with this algorithm. Sensitivity and specificity of FFRW detection were 99.63% and 100%, respectively, and no P waves were falsely classified. It can be concluded that this novel DSP algorithm shows excellent discrimination of FFRWs under off-line conditions and justify the implementation of this algorithm in future pacemakers for real-time discrimination between P waves and FFRWs. This method prevents false mode switching and allows correct and immediate intervention pacing for atrial tachyarrhythmias. PMID:15613124

    3. The complexity of human ribosome biogenesis revealed by systematic nucleolar screening of Pre-rRNA processing factors.

      PubMed

      Tafforeau, Lionel; Zorbas, Christiane; Langhendries, Jean-Louis; Mullineux, Sahra-Taylor; Stamatopoulou, Vassiliki; Mullier, Romain; Wacheul, Ludivine; Lafontaine, Denis L J

      2013-08-22

      Mature ribosomal RNAs (rRNAs) are produced from polycistronic precursors following complex processing. Precursor (pre)-rRNA processing has been extensively characterized in yeast and was assumed to be conserved in humans. We functionally characterized 625 nucleolar proteins in HeLa cells and identified 286 required for processing, including 74 without a yeast homolog. For selected candidates, we demonstrated that pre-rRNA processing defects are conserved in different cell types (including primary cells), defects are not due to activation of a p53-dependent nucleolar tumor surveillance pathway, and they precede cell-cycle arrest and apoptosis. We also investigated the exosome's role in processing internal transcribed spacers (ITSs) and report that 3' end maturation of 18S rRNA involves EXOSC10/Rrp6, a yeast ITS2 processing factor. We conclude that human cells adopt unique strategies and recruit distinct trans-acting factors to carry out essential processing steps, posing fundamental implications for understanding ribosomopathies at the molecular level and developing effective therapeutic agents. PMID:23973377

    4. 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.

    5. 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.

    6. Beta-decay spectroscopy of r-process nuclei around N = 126

      NASA Astrophysics Data System (ADS)

      Hirayama, Y.; Miyatake, H.; Watanabe, Y. X.; Imai, N.; Ishiyama, H.; Jeong, S. C.; Jung, H. S.; Oyaizu, M.; Mukai, M.; Kimura, S.; Sonoda, T.; Wada, M.; Kim, Y. H.; Huyse, M.; Kudryavtsev, Yu.; Van Duppen, P.

      2016-02-01

      KEK Isotope Separation System (KISS) has been developed at RIKEN to study the β-decay properties of neutron-rich isotopes with neutron numbers around N = 126 to understand the astrophysical site of r-process. These nuclei will be produced by multi-nucleon transfer reactions in neutron-rich heavy ion collisions between 136Xe beam and 198Pt target. The KISS consists of an argon gas cell combined with a laser resonance ionization technique for atomic number selection, of an ISOL mass-separation system and of a detector system for the β-decay spectroscopy of nuclei around N = 126. The argon gas cell of KISS is a key component for thermalizing (stopping and neutralizing) and accumulating the unstable nuclei, and selectively ionizing them by using laser. We have performed off-and on-line experiments to study the basic properties of the gas cell as well as KISS. We successfully extracted the laser-ionized stable 198Pt atoms from the KISS at the commissioning on-line experiments. We furthermore extracted laser-ionized unstable 199Pt atoms and confirmed that the measured half-life was in good agreement with the reported value. Now KISS is ready for lifetime measurements of Pt, Ir, and Os isotopes around N = 126.

    7. Complex rupture processes at the Bárðarbunga caldera, Iceland

      NASA Astrophysics Data System (ADS)

      Cesca, Simone; Heimann, Sebastian; Hensch, Martin; Hjörleifsdóttir, Vala; Holohan, Eoghan; Dahm, Torsten

      2015-04-01

      The unrest of the Bárðarbunga volcanic system in summer 2014 has been accompanied by a significant increase in seismicity, which was localized both at the caldera rim and along segments of a major, laterally-propagated dyke. The seismic activity was exceptional for the region, with more than 60 events of magnitude Ml larger than 5.0 recorded in the first three months of activity, which is still ongoing. Our aim here is to provide an explanation of the sustained seismicity at the caldera rim. We rely on regional broadband recordings to perform an inversion of source parameters and to model the source processes for the largest events (above Ml 5.0) in the sequence. Full moment tensor inversion and moment tensor clustering reveal that most events can be classified in two types, which can be well modeled by the superposition of a common sub-vertical compensated linear vector dipole (CLVD) and a normal faulting, which has a different orientation for the two types of events. The analysis of the earthquake source is further extended to smaller magnitudes, by using a waveform correlation approach; this confirms similar rupture processes for weaker events. An apparent discrepancy among seismological observations at local and regional distances, in terms of origin times and radiation patterns, suggest a complex rupture process, composed of different phases. Whereas local data are useful to track the nucleation phase, characterised by a shear failure, regional data can be used to assess the mechanism responsible for the most energetic signal, where the non-DC component becomes more relevant. The combined analysis of local and regional data revealed that, at least during the first phase of the sequence, the type of rupture is conditioned by the location of the rupture nucleation. When the rupture is initiated at the northern rim, the normal faulting component of the moment tensor strikes almost North-South; instead, if the rupture starts at the southern rim, the normal

    8. 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

    9. 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…

    10. 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.

    11. 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.

    12. Plasmid R1 Conjugative DNA Processing Is Regulated at the Coupling Protein Interface▿

      PubMed Central

      Mihajlovic, Sanja; Lang, Silvia; Sut, Marta V.; Strohmaier, Heimo; Gruber, Christian J.; Koraimann, Günther; Cabezón, Elena; Moncalián, Gabriel; de la Cruz, Fernando; Zechner, Ellen L.

      2009-01-01

      Selective substrate uptake controls initiation of macromolecular secretion by type IV secretion systems in gram-negative bacteria. Type IV coupling proteins (T4CPs) are essential, but the molecular mechanisms governing substrate entry to the translocation pathway remain obscure. We report a biochemical approach to reconstitute a regulatory interface between the plasmid R1 T4CP and the nucleoprotein relaxosome dedicated to the initiation stage of plasmid DNA processing and substrate presentation. The predicted cytosolic domain of T4CP TraD was purified in a predominantly monomeric form, and potential regulatory effects of this protein on catalytic activities exhibited by the relaxosome during transfer initiation were analyzed in vitro. TraDΔN130 stimulated the TraI DNA transesterase activity apparently via interactions on both the protein and the DNA levels. TraM, a protein interaction partner of TraD, also increased DNA transesterase activity in vitro. The mechanism may involve altered DNA conformation as TraM induced underwinding of oriT plasmid DNA in vivo (ΔLk = −4). Permanganate mapping of the positions of duplex melting due to relaxosome assembly with TraDΔN130 on supercoiled DNA in vitro confirmed localized unwinding at nic but ruled out formation of an open complex compatible with initiation of the TraI helicase activity. These data link relaxosome regulation to the T4CP and support the model that a committed step in the initiation of DNA export requires activation of TraI helicase loading or catalysis. PMID:19767437

    13. The membrane-biofilm reactor (MBfR) as a counter-diffusional biofilm process.

      PubMed

      Nerenberg, Robert

      2016-04-01

      The membrane-biofilm reactor (MBfR), sometimes known as the membrane-aerated biofilm reactor (MABR), is an emerging treatment technology based on gas-transferring membranes. The membranes typically supply a gaseous electron donor or acceptor substrate, such as oxygen, hydrogen, and methane. The substrate diffuses through the membrane to a biofilm naturally forming on the membrane outer surface. The complementary substrate (electron donor or acceptor) typically diffuses from the bulk liquid into the biofilm, making MBfR counter diffusional. This paper reviews the unique behavior of counter-diffusional biofilms and highlights recent research on the MBfR. Key advances include insights into the microbial community structure of MBfRs, applying the MBfR to novel contaminants, providing a better understanding of biofilm morphology and its effects on MBfR behavior, and the development of methane-based MBfR applications. These advances are likely to further the development of the MBfR for environmental applications, such as energy-efficient wastewater treatment and advanced water treatment. PMID:26874609

    14. Effects of charge transfer on the ESIPT process in methyl 5-R-salicylates.

      PubMed

      Catalán, J

      2015-02-12

      The fluorescent behavior of the methyl-5-R-salicylates is analyzed in media of negligible acidity and basicity so that the methyl-5-R-salicylates may undergo solvent dipolarity changes or not in a controlled manner based on the following guidelines: (i) The molecular forms of these methyl-5-R-salicylates possessing an intramolecular hydrogen bond (IMHB) between their hydroxyl group and ether type oxygen (rotated tautomer) undergo no excited-state intramolecular proton transfer (ESIPT) in their first excited electronic state; (ii) on the other hand, the molecular species with an IMHB between its hydroxyl group and carbonyl oxygen (normal tautomer) exhibits both ESIPT and normal emission when charge transfer (CT) from the R-substituent to the phenol group is slight to moderate, but only normal emission is monitored when CT is strong. The special insensitivity of the first UV absorption band for the normal tautomer of methylsalicylate (MS, with R = H) to the polarity of the solvent is not echoed by the normal forms of methyl-5-R-salicylates containing substituents R with a substantial effect of CT in the IMHB of the compound. These solvatochromic features of MS are shared by the emissions of its derivatives. The photophysical evidence found for the methyl-5-R-salicylates confirms the photophysical model recently reported (Phys. Chem. Chem. Phys. 2012, 14, 8903-8909), which assigns three fluorescent emissions to the methyl-5-R-salicylates: two of them coming from the IMHB normal tautomer, which undergoes ESIPT, and another from the IMHB rotated tautomer, which cannot undergo ESIPT. PMID:24967729

    15. Neutron Capture Rates near A=130 which Effect a Global Change to the r-Process Abundance Distribution

      SciTech Connect

      Surman, Rebecca; Beun, Joshua; Mclaughlin, Gail C; Hix, William Raphael

      2009-01-01

      We investigate the impact of neutron capture rates near the A=130 peak on the r-process abundance pattern. We show that these capture rates can alter the abundances of individual nuclear species, not only in the region of A=130 peak but also throughout the abundance pattern. We discuss in general the nonequilibrium processes that produce these abundance changes and determine which capture rates have the most significant impact.

    16. The role of fission on 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.

      2016-06-01

      The comparison between observational abundance features and those obtained from nucleosynthesis predictions of stellar evolution and/or explosion simulations can scrutinize two aspects: (a) the conditions in the astrophysical production site and (b) the quality of the nuclear physics input utilized. Here we test the abundance features of r-process nucleosynthesis calculations using four different fission fragment distribution models. Furthermore, we explore the origin of a shift in the third r-process peak position in comparison with the solar r-process abundances which has been noticed in a number of merger nucleosynthesis predictions. We show that this shift occurs during the r-process freeze-out when neutron captures and β-decays compete and an (n,γ)-(γ,n) equilibrium is not maintained anymore. During this phase neutrons originate mainly from fission of material above A = 240. We also investigate the role of β-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.

    17. On the robustness of the r-process in neutron-star mergers against variations of nuclear masses

      NASA Astrophysics Data System (ADS)

      Mendoza-Temis, J. J.; Wu, M. R.; Martínez-Pinedo, G.; Langanke, K.; Bauswein, A.; Janka, H.-T.; Frank, A.

      2016-07-01

      r-process calculations have been performed for matter ejected dynamically in neutron star mergers (NSM), such calculations are based on a complete set of trajectories from a three-dimensional relativistic smoothed particle hydrodynamic (SPH) simulation. Our calculations consider an extended nuclear reaction network, including spontaneous, β- and neutron-induced fission and adopting fission yield distributions from the ABLA code. In this contribution we have studied the sensitivity of the r-process abundances to nuclear masses by using diferent mass models for the calculation of neutron capture cross sections via the statistical model. 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.

    18. A Study on the Application of Fuzzy Analytic Hierarchy Process to Construct an R and D Management Effectiveness Evaluation Index for Taiwan=s High-Tech Industry

      NASA Astrophysics Data System (ADS)

      Liu, Pang-Lo; Tsai, Chih-Hung

      The high-tech industry is one of the most important links in Taiwan=s economic development. Research and Development (R and D) technology and management is the key to sustainable enterprises. However, the involvement of many difficult quantification factors and the fuzzy character of human subjective judgment on the R and D management content and process makes R and D management effectiveness evaluation more difficult. This study adopted the Fuzzy Analytic Hierarchy Process (FAHP) from the Fuzzy Theory to develop a set of systematized evaluation indices for R and D management effectiveness. This method is designed to assist enterprises in conducting R and D management effectiveness evaluations to achieve the goal increasing enterprise competitiveness. According to the outcome of this study, the researchers found the importance and weight of these major aspects for Taiwan=s high-tech industry=s R and D management effectiveness is shown as follows: R and D and Innovation (0.346), R and D Process (0.269), Customer (0.209) and R and D Personnel (0.184). Moreover, among the effectiveness evaluations on implementing the R and D management in certain industries, R and D and Innovation and R and D Process are determined as the important item that revealed how Taiwan=s high-tech industries are particular about achieving R and D management through the completed R and D and innovation process.

    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 β-decays compete and an (n,γ)-(γ,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 β-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. Dynamic conformational model for the role of ITS2 in pre-rRNA processing in yeast.

      PubMed Central

      Côté, Colette A; Greer, Chris L; Peculis, Brenda A

      2002-01-01

      Maturation of the large subunit rRNAs includes a series of cleavages that result in removal of the internal transcribed spacer (ITS2) that separates mature 5.8S and 25/28S rRNAs. Previous work demonstrated that formation of higher order secondary structure within the assembling pre-ribosomal particle is a prerequisite for accurate and efficient pre-rRNA processing. To date, it is not clear which specific sequences or secondary structures are required for processing. Two alternative secondary structure models exist for Saccharomyces cerevisiae ITS2. Chemical and enzymatic structure probing and phylogenetic comparisons resulted in one structure (Yeh & Lee, J Mol Biol, 1990, 211:699-712) referred to here as the "hairpin model." More recently, an alternate folded structure was proposed (Joseph et al., Nucleic Acids Res, 1999, 27:4533-4540), called here the "ring model." We have used a functional genetic assay to examine the potential significance of these predicted structures in processing. Our data indicate that elements of both structural models are important in efficient processing. Mutations that prevent formation of ring-specific structures completely blocked production of mature 25S rRNA, whereas those that primarily disrupt hairpin elements resulted in reduced levels of mature product. Based on these results, we propose a dynamic conformational model for the role of ITS2 in processing: Initial formation of the ring structure may be required for essential, early events in processing complex assembly and may be followed by an induced transition to the hairpin structure that facilitates subsequent processing events. In this model, yeast ITS2 elements may provide in cis certain of the functions proposed for vertebrate U8 snoRNA acting in trans. PMID:12088151

    1. Compact Stellar Binary Assembly in the First Nuclear Star Clusters and r-process Synthesis in the Early Universe

      NASA Astrophysics Data System (ADS)

      Ramirez-Ruiz, Enrico; Trenti, Michele; MacLeod, Morgan; Roberts, Luke F.; Lee, William H.; Saladino-Rosas, Martha I.

      2015-04-01

      Investigations of elemental abundances in the ancient and most metal deficient stars are extremely important because they serve as tests of variable nucleosynthesis pathways and can provide critical inferences of the type of stars that lived and died before them. The presence of r-process elements in a handful of carbon-enhanced metal-poor (CEMP-r) stars, which are assumed to be closely connected to the chemical yield from the first stars, is hard to reconcile with standard neutron star mergers. Here we show that the production rate of dynamically assembled compact binaries in high-z nuclear star clusters can attain a sufficient high value to be a potential viable source of heavy r-process material in CEMP-r stars. The predicted frequency of such events in the early Galaxy, much lower than the frequency of Type II supernovae but with significantly higher mass ejected per event, can naturally lead to a high level of scatter of Eu as observed in CEMP-r stars.

    2. 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

    3. 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

    4. Abundances of r-PROCESS Elements in the Photosphere of Red Supergiant Star PMMR23 in Small Magellanic Cloud

      NASA Astrophysics Data System (ADS)

      Vasil'Eva, S. V.; Gopka, V. F.; Yushchenko, A. V.; Andryevsky, S. M.

      Detailed analysis of chemical abundances determined from high-resolution CCD-spectrogram of supergiant star PMMR23 (K5 I) in SMC is presented. The observation were obtained at 3.6 meter ESO La Silla telescope by Hill (1997). Spectral resolving power is near R=30.000. The wavelength coverage is 5050-7200 A. The abundances of iron and 15 r-, s-processes elements are found. The abundances of Cu, Zr, Mo, Ru, Pr, Sm, Gd, Dy, Er are found for the first time. The abundances of elements with atomic numbers less than 55 are deficient with respect to the Sun. The mean underabundance is near 0.7 dex. The abundances of barium and lanthanides are near solar values. The overabundances of these elements with respect to iron are in the range from 0.4 tp 0.9 dex. The abundances of heavy lanthanides are higher than the abundances of light lanthanides. The abundance pattern of PMMR23 can be fitted by scaled solar r-process distribution. The atmosphere of PMMR23 is enriched by r-process elements.

    5. Can we monitor the bare soil freeze-thaw process using GNSS-R?: a simulation study

      NASA Astrophysics Data System (ADS)

      Wu, Xuerui; Jin, Shuanggen

      2014-11-01

      GNSS-R has recently emerged as a new prosperous remote sensing tool in ocean surface, snow/ice surface and land surface. In this paper, the possible application in sensing the bare soil freeze-thaw process is investigated with GNSS-R. The Fresnel reflectivity from the wave synthesis technique is used to get the circular polarization reflectivity. Large differences are found for the Fresnel reflectivities at V, H, RR polarizations during bare soil freeze-thaw process, but there are almost no differences as for LR polarization. Therefore if a special GNSS-R receiver is designed, the reflected signals of RR polarization should be efficiently used. For GPS multipath reflectometry, the improved Fresnel reflectivity is inserted into the fully polarimetric forward multipath model to get the simulated GPS L1 observables: SNR, carrier phase multipath error and pseudorange code multipath error, which are used to estimate the bare soil freeze-thaw process. Compared to the thawed soil, the amplitudes of GPS observables are smaller for the frozen soil. Therefore, it is possible to monitor bare soil freeze-thaw process with ground geodetic GPS receivers.

    6. 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.

    7. Study on rheo-diecasting process of 7075R alloys by SA-EMS melt homogenized treatment

      NASA Astrophysics Data System (ADS)

      Zhihua, G.; Jun, X.; Zhifeng, Z.; Guojun, L.; Mengou, T.

      2016-03-01

      An advanced melt processing technology, spiral annular electromagnetic stirring (SA-EMS) based on the annular electromagnetic stirring (A-EMS) process was developed for manufacturing Al-alloy components with high integrity. The SA-EMS process innovatively combines non-contact electromagnetic stirring and a spiral annular chamber with specially designed profiles to in situ make high quality melt slurry, and intensive forced shearing can be achieved under high shear rate and high intensity of turbulence inside the spiral annular chamber. In this paper, the solidification microstructure and hardness of 7075R alloy die-casting connecting rod conditioned by the SA-EMS melt processing technology were investigated. The results indicate that, the SA-EMS melt processing technology exhibited superior grain refinement and remarkable structure homogeneity. In addition, it can evidently enhance the mechanical performance and reduce the crack tendency.

    8. PV Manufacturing R&D Project Status & Accomplishments Under ''In-Line Diagnostics & Intelligent Processing''

      SciTech Connect

      Brown, K. E.; Mitchell, R. L.; Bower, W. I.; King, R.

      2005-02-01

      In 1991, the U.S. Department of Energy (DOE), National Renewable Energy Laboratory, and Sandia National Laboratories embarked on a research partnership with the U.S. photovoltaic (PV) industry by cost-sharing industry-based R&D efforts. The PV Manufacturing R&D (PVMR&D) Project, an extension of the earlier PV Manufacturing Technology (PVMaT) Project, aims at streamlining and improving the current PV manufacturing technology to enable U.S. manufacturers to compete in the global marketplace. Currently, PVMR&D has ten active subcontracts with manufacturers working in several facets of the U.S. PV industry; four subcontracts were completed within the past year.

    9. Explosive Nucleosynthesis in Magnetohydrodynamical Jets from Collapsars. II --- Heavy-Element Nucleosynthesis of s, p, r-Processes

      NASA Astrophysics Data System (ADS)

      Ono, M.; Hashimoto, M.; Fujimoto, S.; Kotake, K.; Yamada, S.

      2012-10-01

      We investigate the nucleosynthesis in a massive star of 70 M_{⊙} with solar metallicity in the main sequence stage. The helium core mass after hydrogen burning corresponds to 32 M_{⊙}. Nucleosynthesis calculations have been performed during the stellar evolution and the jetlike supernova explosion of a collapsar model. We focus on the production of elements heavier than iron group nuclei. Nucleosynthesis calculations have been accomplished consistently from hydrostatic to dynamic stages by using large nuclear reaction networks, where the weak s-, p-, and r-processes are taken into account. We confirm that s-elements of 60 < A < 90 are highly overproduced relative to the solar abundances in the hydrostatic nucleosynthesis. During oxygen burning, p-elements of A > 90 are produced via photodisintegrations of seed s-elements. However, the produced p-elements are disintegrated in later stages except for ^{180}Ta. In the explosive nucleosynthesis, elements of 90 < A < 160 are significantly overproduced relative to the solar values owing to the r-process, which is very different from the results of spherical explosion models. Only heavy p-elements (N > 50) are overproduced via the p-process because of the low peak temperatures in the oxygen- and neon-rich layers. Compared with the previous study of r-process nucleosynthesis calculations in the collapsar model of 40 M_{⊙} by Fujimoto et al. [S. Fujimoto, M. Hashimoto, K. Kotake and S. Yamada, Astrophys. J. 656 (2007), 382; S. Fujimoto, N. Nishimura and M. Hashimoto, Astrophys. J. 680 (2008), 1350], our jet model cannot contribute to the third peak of the solar r-elements and intermediate p-elements, which have been much produced because of the distribution of the lowest part of electron fraction in the ejecta. Averaging the overproduction factors over the progenitor masses with the use of Salpeter's IMF, we suggest that the 70 M_{⊙} star could contribute to the solar weak s}-elements of 60 < A < 90 and neutron

    10. 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.

    11. The Unreasonable Weakness of R-process Cosmic Rays in the Neutron-star-merger Nucleosynthesis Scenario

      NASA Astrophysics Data System (ADS)

      Kyutoku, Koutarou; Ioka, Kunihito

      2016-08-01

      We reach the robust conclusion that, by combining the observed cosmic rays of r-process elements with the fact that the velocity of the neutron-star-merger ejecta is much higher than that of the supernova ejecta, either (1) the reverse shock in the neutron-star-merger ejecta is a very inefficient accelerator that converts less than 0.003% of the ejecta kinetic energy to the cosmic-ray energy or (2) the neutron star merger is not the origin of the Galactic r-process elements. We also find that the acceleration efficiency should be less than 0.1% for the reverse shock of the supernova ejecta with observed cosmic rays lighter than the iron.

    12. Impact of the first-forbidden β decay on the production of A ∼ 195 r-process peak

      NASA Astrophysics Data System (ADS)

      Nishimura, Nobuya; Podolyák, Zsolt; Fang, Dong-Liang; Suzuki, Toshio

      2016-05-01

      We investigated the effects of first-forbidden transitions in β decays on the production of the r-process A ∼ 195 peak. The theoretical calculated β-decay rates with β-delayed neutron emission were examined using several astrophysical conditions. As the FF decay is dominant in N ∼ 126 neutron-rich nuclei, their inclusion shortens β-decay lifetimes and shifts the abundance peak towards higher masses. Additionally, the inclusion of the β-delayed neutron emission results in a wider abundance peak, and smoothens the mass distribution by removing the odd-even mass staggering. The effects are commonly seen in the results of all adopted astrophysical models. Nevertheless there are quantitative differences, indicating that remaining uncertainty in the determination of half-lives for N = 126 nuclei is still significant in order to determine the production of the r-process peak.

    13. 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

    14. 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.

    15. 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...

    16. 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.

    17. On the role of the supramarginal gyrus in phonological processing and verbal working memory: evidence from rTMS studies.

      PubMed

      Deschamps, Isabelle; Baum, Shari R; Gracco, Vincent L

      2014-01-01

      The supramarginal gyrus (SMG) is activated for phonological processing during both language and verbal working memory tasks. Using rTMS, we investigated whether the contribution of the SMG to phonological processing is domain specific (specific to phonology) or more domain general (specific to verbal working memory). A measure of phonological complexity was developed based on sonority differences and subjects were tested after low frequency rTMS on a same/different judgment task and an n-back verbal memory task. It was reasoned that if the phonological processing in the SMG is more domain general, i.e., related to verbal working memory demands, performance would be more affected by the rTMS during the n-back task than during the same/different judgment task. Two auditory experiments were conducted. The first experiment demonstrated that under conditions where working memory demands are minimized (i.e. same/different judgment), repetitive stimulation had no effect on performance although performance varied as a function of phonological complexity. The second experiment demonstrated that during a verbal working memory task (n-back task), where phonological complexity was also manipulated, subjects were less accurate and slower at performing the task after stimulation but the effect of phonology was not affected. The results confirm that the SMG is involved in verbal working memory but not in the encoding of sonority differences. PMID:24184438

    18. 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.

    19. s-process studies in the light of new experimental cross sections - Distribution of neutron fluences and r-process residuals

      NASA Technical Reports Server (NTRS)

      Kaeppeler, F.; Beer, H.; Wisshak, K.; Clayton, D. D.; Macklin, R. L.; Ward, R. A.

      1982-01-01

      A best set of neutron-capture cross sections has been evaluated for the most important s-process isotopes. With this data base, s-process studies have been carried out using the traditional model which assumes a steady neutron flux and an exponential distribution of neutron irradiations. The calculated sigma-N curve is in excellent agreement with the empirical sigma-N-values of pure s-process nuclei. Simultaneously, good agreement is found between the difference of solar and s-process abundances and the abundances of pure r-process nuclei. The abundance pattern of the iron group elements where s-process results complement the abundances obtained from explosive nuclear burning is discussed. The results obtained from the traditional s-process model such as seed abundances, mean neutron irradiations, or neutron densities are compared to recent stellar model calculations which assume the He-burning shells of red giant stars as the site for the s-process.

    20. Classification of Counseling and Therapy Theorists, Methods, Processes, and Goals: The E-R-A Model.

      ERIC Educational Resources Information Center

      L'Abate, Luciano

      1981-01-01

      Presents an Emotionality-Rationality-Activity model that integrates recent classifications of counseling and psychotherapy. The model also serves as a theoretical basis from which methods, goals, and processes during counseling, psychotherapy, and training can be derived and integrated. (Author)

    1. 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.

    2. Ligation of FcγR Alters Phagosomal Processing of Protein via Augmentation of NADPH Oxidase Activity.

      PubMed

      Balce, Dale R; Rybicka, Joanna M; Greene, Catherine J; Ewanchuk, Benjamin W; Yates, Robin M

      2016-07-01

      Proteolysis and the reduction of disulfides, both major components of protein degradation, are profoundly influenced by phagosomal redox conditions in macrophages. We evaluated the activation of phagocytic receptors that are known to influence activation of the phagocyte NADPH oxidase (NOX2), and its effect on phagosomal protein degradation. Population-based and single phagosome analyses of phagosomal chemistries in murine macrophages revealed that activation of NOX2 via the Fcγ receptor (FcγR) during phagocytosis decreased rates of proteolysis and disulfide reduction. Immunoglobulin G (IgG)-stimulated reactive oxygen species (ROS) production and the inhibition of phagosomal proteolysis and disulfide reduction were dependent on NOX2, FcγR and protein kinase C (PKC)/spleen tyrosine kinase (Syk) signaling. In contrast, low levels of ROS production were observed following the phagocytosis of unopsonized beads, which resulted in higher rates of phagosomal proteolysis and disulfide reduction. Phagosomes displayed autonomy with respect to FcγR-mediated differences in NOX2 activation and proteolysis, as phagosomes containing unopsonized cargo retained low NOX2 activation and high proteolysis even in the presence of phagosomes containing IgG-opsonized cargo in the same macrophage. These results show that opsonization of phagocytic cargo results in vastly different phagosomal processing of proteins through the FcγR-triggered, PKC/Syk-dependent local assembly and activation of NOX2. PMID:27020146

    3. 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.

    4. 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 α-element deficiencies cannot be due to the Type Ia supernova (SN Ia) time-delay scenario of Tinsley. Instead, the evidence points to low [α/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 α-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.

    5. Chemistry of the Sagittarius Dwarf Galaxy: A Top-light Initial Mass Function, Outflows, and the R-process

      NASA Astrophysics Data System (ADS)

      McWilliam, Andrew; Wallerstein, George; Mottini, Marta

      2013-12-01

      From chemical abundance analysis of stars in the Sagittarius dwarf spheroidal galaxy (Sgr), we conclude that the α-element deficiencies cannot be due to the Type Ia supernova (SN Ia) time-delay scenario of Tinsley. Instead, the evidence points to low [α/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] 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 α-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] r with [Fe/H] in Sgr, indicates that massive SNe II (gsim30 M ⊙) 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 13C pocket in low-mass AGB stars is required. Sgr has the lowest [Rb/Zr] ratios known, consistent with pollution by low-mass (lsim2 M ⊙) 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.

    6. EVALUATION OF DIFFERENT SIGNAL PROCESSING OPTIONS IN UNILATERAL AND BILATERAL COCHLEAR FREEDOM IMPLANT RECIPIENTS USING R-SPACE™ BACKGROUND NOISE

      PubMed Central

      Brockmeyer, Alison M.; Potts, Lisa G.; Brockmeyer, Alison

      2013-01-01

      Background Difficulty understanding in background noise is a common complaint of cochlear implant (CI) recipients. Programming options are available to improve speech recognition in noise for CI users including Automatic Dynamic Range Optimization (ADRO), Autosensitivity Control (ASC), and BEAM. The processing option, however, which results in the best speech recognition in noise, is unknown. In addition, laboratory measures of these processing options often show greater degrees of improvement than reported by participants in everyday listening situations. To address this issue, Compton-Conley and colleagues developed a test system to replicate a restaurant environment. The R-SPACE™ consists of eight loudspeakers positioned in a 360 degree arc and utilizes a recording made at a restaurant of background noise. Purpose The present study measured speech recognition in the R-SPACE™ with four processing options: standard dual-port directional (STD), ADRO, ASC, and BEAM. Research Design A repeated measures, within-subject design was used to evaluate the four different processing options at two noise levels. Study Sample Twenty-seven unilateral and three bilateral adult Nucleus Freedom cochlear implant recipients. Intervention The participants’ everyday program (with no additional processing) was used as the STD program. ADRO, ASC, and BEAM were added individually to the STD program to create a total of four programs. Data Collection and Analysis Participants repeated HINT sentences presented at a 0 degree azimuth with R-SPACE™ restaurant noise at two noise levels, 60 and 70 dB SPL. The Reception Threshold for Sentences (RTS) was obtained for each processing condition and noise level. Results In 60 dB SPL noise, BEAM processing resulted in the best RTS, with a significant improvement over STD and ADRO processing. In 70 dB SPL noise, ASC and BEAM processing had significantly better mean RTSs compared to STD and ADRO processing. Comparison of noise levels showed

    7. VizieR Online Data Catalog: s-process in low-metallicity stars (Bisterzo+, 2010)

      NASA Astrophysics Data System (ADS)

      Bisterzo, S.; Gallino, R.; Straniero, O.; Cristallo, S.; Kappeler, F.

      2010-11-01

      A large sample of carbon-enhanced metal-poor stars enriched in s-process elements (CEMP-s) have been observed in the Galactic halo. These stars of low mass (M~0.9M⊙) are located on the main-sequence or the red-giant phase, and do not undergo third dredge-up (TDU) episodes. The s-process enhancement is most plausibly due to accretion in a binary system from a more massive companion when on the asymptotic giant branch (AGB) phase (now a white dwarf). In order to interpret the spectroscopic observations, updated AGB models are needed to follow in detail the s-process nucleosynthesis. We present nucleosynthesis calculations based on AGB stellar models obtained with Frascati Raphson-Newton Evolutionary Code (FRANEC) for low initial stellar masses and low metallicities. For a given metallicity, a wide spread in the abundance of the s-process elements is obtained by varying the amount of 13C and its profile in the pocket, where the 13C(α, n)16O reaction is the major neutron source, releasing neutrons in radiative conditions during the interpulse phase. We also account for the second neutron source 22Ne(α,n)25Mg, partially activated during convective thermal pulses. (7 data files).

    8. 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

    9. 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

    10. 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.

    11. Continuing Development of GOES-R SUVI Automated Solar Image Processing

      NASA Astrophysics Data System (ADS)

      Hill, S. M.; Darnel, J.; Vickroy, J.; Steenburgh, R. A.; Rigler, E. J.

      2013-12-01

      NOAA's Space Weather Prediction Center (SWPC) is the Nation's official source of space weather alerts, watches and warnings. In that role, the Center will be ingesting GOES-R Solar Ultraviolet Imager (SUVI) data beginning in the 2015-16 timeframe. Along with other NOAA and non-NOAA sources of solar imagery these observations are used by SWPC forecasters to inform their analysis (nowcast) and forecasts and also as sources of data to run empirical and numerical models. A supervised, multispectral, Bayesian pixel classifier has been developed and produces what are referred to as thematic maps to assist forecasters in their analysis. These maps represent classes of pixels including: space, coronal holes, quiet corona, filaments, active regions, and flares. The thematic maps product underwent initial operational test and evaluation at SWPC in 2012-13. The test used synoptic data from the Atmospheric Imaging Array (AIA) on NASA's SDO mission in near real time as a proxy for SUVI data. The thematic maps product has been upgraded and retrained to incorporate H-alpha imagery to better discriminate between filament channels and coronal holes. We present ongoing results of the operational test and evaluation for thematic maps. Also, we include initial results for automated flare location and coronal hole boundary location that depend on thematic maps as inputs.

    12. From Radtrack to eMWaste(r) G2 process-based integration

      SciTech Connect

      Bland, Jesse John

      2015-02-01

      This paper provides a process-based examination of the integration of two separate but related software applications into Sandia National Laboratories’ (SNL’s) Radioactive and Mixed Waste Management Facility’s (RMWMF) data management system. First, data collection will be upgraded through the use of a new web-based Waste Description and Disposal Request (WDDR), which SNL personnel whose work creates radioactive and hazardous waste (generators) will use to characterize dozens of specific attributes of each waste parcel. Second, a commercial software package for data storage and manipulation — eMWaste® G2 by Attention IT — will replace two existing software applications and will track all radioactive and mixed waste at Sandia. Integrating these applications into a web-based system will give the RMWMF increased system flexibility, reduced reliance on key personnel, and improved document control, traceability and efficiency. To meet these goals and ensure the applications are developed in an efficient, quality-oriented environment, it is critical to first conduct a thorough evaluation of the affected processes. This paper will analyze the processes supported by the new applications and the requirements for a successful integration. A comprehensive analysis of both project flow and data management requirements, illustrated through original flow diagrams and other charts, will provide support to the development team and programmers as they work to integrate the applications into the new system.

    13. 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.

    14. The neutron long counter NERO for studies of β-delayed neutron emission in the r-process

      NASA Astrophysics Data System (ADS)

      Pereira, J.; Hosmer, P.; Lorusso, G.; Santi, P.; Couture, A.; Daly, J.; Del Santo, M.; Elliot, T.; Görres, J.; Herlitzius, C.; Kratz, K.-L.; Lamm, L. O.; Lee, H. Y.; Montes, F.; Ouellette, M.; Pellegrini, E.; Reeder, P.; Schatz, H.; Schertz, F.; Schnorrenberger, L.; Smith, K.; Stech, E.; Strandberg, E.; Ugalde, C.; Wiescher, M.; Wöhr, A.

      2010-06-01

      The neutron long counter NERO was built at the National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, for measuring β-delayed neutron-emission probabilities. The detector was designed to work in conjunction with a β-delay implantation station, so that β decays and β-delayed neutrons emitted from implanted nuclei can be measured simultaneously. The high efficiency of about 40%, for the range of energies of interest, along with the small background, are crucial for measuring β-delayed neutron emission branchings for neutron-rich r-process nuclei produced as low intensity fragmentation beams in in-flight separator facilities.

    15. Beta-decay studies of nickel-78 and other neutron-rich nuclei in the astrophysical r-process

      NASA Astrophysics Data System (ADS)

      Hosmer, Paul Thomas

      The β-decay properties of several neutron-rich nuclei including the doubly-magic 78Ni were studied. A low-energy neutron detector NERO was designed and calibrated for use in these measurements. β-decay measurements, especially those that combine both half-life and neutron-emission probability measurements, can offer first tests of nuclear theories of neutron-rich nuclei. In addition, 78Ni is an important waiting-point in the astrophysical r-process. The results of the measurements are compared to several nuclear models, and the astrophysical implications are explored.

    16. A Comprehensive Study on Coastline Process and Sedimentary Dynamics, Sardinera Beach, Mona Island, P.R.

      NASA Astrophysics Data System (ADS)

      Rodriguez-Delga, A. M.; Ramirez, W. R.

      2008-12-01

      Sardinera beach in Mona Island, Puerto Rico, has a great recreational and ecological value and is an important research place to gather information on shoreline processes in an area far from the main land and with only scarce man made influences. Beach rock exposures present along the shoreline in Sardinera Beach have increased considerably during the last decade. A new management plan is being developed for Mona Island and the Department of Natural Resources (DNRA) of Puerto Rico wants to better understand the beach sand dynamics on this and other Mona Island beaches. This research includes field and laboratory work that characterize coastal sedimentary processes and helps to better understand the shoreline changes as well as seasonal variations in sand movement and composition. This work also establish the logistics and methodology basis for further studies that will expand to other Mona Island beaches. Benchmarks, GPS coordinates, and landmarks were used to establish ten permanent beach profiles along Sardinera Beach. Beach profiles were (and will be) measured monthly. Sardinera Beach sands are composed mostly of carbonate (CaCO3) components, products of the combination of biological, chemical and diagenetic processes, high grade of micritization, and of lithic limestone fragments. Sand composition differences between Sardinera Beach, the Mona Shelf and adjacent beach, reef crest and reef lagoon systems suggest Sardinera sands are not replenished by the modern marine components produced in these environments. The input of "fresh bioclasts" in this beach seems to be limited by natural (beach rock) and mane made (dock) barriers along the shore and by alteration in the current patterns produced by the man made aperture of the reef. Sardinera's micritized and recrystalized sand deposits seem to have been re-transported between the reefal lagoon and the beach. Sand volume analysis indicates a total sand loss of 1,322 m3 between the months of September to April

    17. Processing of double-R-loops in (CAG)·(CTG) and C9orf72 (GGGGCC)·(GGCCCC) repeats causes instability.

      PubMed

      Reddy, Kaalak; Schmidt, Monika H M; Geist, Jaimie M; Thakkar, Neha P; Panigrahi, Gagan B; Wang, Yuh-Hwa; Pearson, Christopher E

      2014-01-01

      R-loops, transcriptionally-induced RNA:DNA hybrids, occurring at repeat tracts (CTG)n, (CAG)n, (CGG)n, (CCG)n and (GAA)n, are associated with diseases including myotonic dystrophy, Huntington's disease, fragile X and Friedreich's ataxia. Many of these repeats are bidirectionally transcribed, allowing for single- and double-R-loop configurations, where either or both DNA strands may be RNA-bound. R-loops can trigger repeat instability at (CTG)·(CAG) repeats, but the mechanism of this is unclear. We demonstrate R-loop-mediated instability through processing of R-loops by HeLa and human neuron-like cell extracts. Double-R-loops induced greater instability than single-R-loops. Pre-treatment with RNase H only partially suppressed instability, supporting a model in which R-loops directly generate instability by aberrant processing, or via slipped-DNA formation upon RNA removal and its subsequent aberrant processing. Slipped-DNAs were observed to form following removal of the RNA from R-loops. Since transcriptionally-induced R-loops can occur in the absence of DNA replication, R-loop processing may be a source of repeat instability in the brain. Double-R-loop formation and processing to instability was extended to the expanded C9orf72 (GGGGCC)·(GGCCCC) repeats, known to cause amyotrophic lateral sclerosis and frontotemporal dementia, providing the first suggestion through which these repeats may become unstable. These findings provide a mechanistic basis for R-loop-mediated instability at disease-associated repeats. PMID:25147206

    18. 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.

    19. Nuclear Structure and Astrophysics r-PROCESS with Covariant Density Functional Theory

      NASA Astrophysics Data System (ADS)

      Meng, J.; Long, W. H.; Niu, Z. M.; Sun, B.; Zhou, S. G.

      2010-09-01

      The density functional theory (DFT) with a minimal number of parameters allows a very successful phenomenological description of ground state properties of nuclei all over the periodic table. Recent progresses on the application of the covariant density functional theory as well as its extensions by the group in Beijing for a series of interests and hot topics in nuclear astrophysics and nuclear structure are reviewed, including the rapid neutron-capture process, Th/U chronometer, halo and giant halo in density dependent relativistic Hartree-Fock-Bogoliubov, and neutron halo in deformed nuclei.

    20. 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.

    1. Chloroplast RNA-Binding Protein RBD1 Promotes Chilling Tolerance through 23S rRNA Processing in Arabidopsis.

      PubMed

      Wang, Shuai; Bai, Ge; Wang, Shu; Yang, Leiyun; Yang, Fen; Wang, Yi; Zhu, Jian-Kang; Hua, Jian

      2016-05-01

      Plants have varying abilities to tolerate chilling (low but not freezing temperatures), and it is largely unknown how plants such as Arabidopsis thaliana achieve chilling tolerance. Here, we describe a genome-wide screen for genes important for chilling tolerance by their putative knockout mutants in Arabidopsis thaliana. Out of 11,000 T-DNA insertion mutant lines representing half of the genome, 54 lines associated with disruption of 49 genes had a drastic chilling sensitive phenotype. Sixteen of these genes encode proteins with chloroplast localization, suggesting a critical role of chloroplast function in chilling tolerance. Study of one of these proteins RBD1 with an RNA binding domain further reveals the importance of chloroplast translation in chilling tolerance. RBD1 is expressed in the green tissues and is localized in the chloroplast nucleoid. It binds directly to 23S rRNA and the binding is stronger under chilling than at normal growth temperatures. The rbd1 mutants are defective in generating mature 23S rRNAs and deficient in chloroplast protein synthesis especially under chilling conditions. Together, our study identifies RBD1 as a regulator of 23S rRNA processing and reveals the importance of chloroplast function especially protein translation in chilling tolerance. PMID:27138552

    2. Chloroplast RNA-Binding Protein RBD1 Promotes Chilling Tolerance through 23S rRNA Processing in Arabidopsis

      PubMed Central

      Yang, Leiyun; Yang, Fen; Wang, Yi; Zhu, Jian-Kang; Hua, Jian

      2016-01-01

      Plants have varying abilities to tolerate chilling (low but not freezing temperatures), and it is largely unknown how plants such as Arabidopsis thaliana achieve chilling tolerance. Here, we describe a genome-wide screen for genes important for chilling tolerance by their putative knockout mutants in Arabidopsis thaliana. Out of 11,000 T-DNA insertion mutant lines representing half of the genome, 54 lines associated with disruption of 49 genes had a drastic chilling sensitive phenotype. Sixteen of these genes encode proteins with chloroplast localization, suggesting a critical role of chloroplast function in chilling tolerance. Study of one of these proteins RBD1 with an RNA binding domain further reveals the importance of chloroplast translation in chilling tolerance. RBD1 is expressed in the green tissues and is localized in the chloroplast nucleoid. It binds directly to 23S rRNA and the binding is stronger under chilling than at normal growth temperatures. The rbd1 mutants are defective in generating mature 23S rRNAs and deficient in chloroplast protein synthesis especially under chilling conditions. Together, our study identifies RBD1 as a regulator of 23S rRNA processing and reveals the importance of chloroplast function especially protein translation in chilling tolerance. PMID:27138552

    3. New calculations of gross β-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 β-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 β- 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.

    4. New Half-lives of r-process Zn and Ga Isotopes Measured with Electromagnetic Separation

      NASA Astrophysics Data System (ADS)

      Madurga, M.; Surman, R.; Borzov, I. N.; Grzywacz, R.; Rykaczewski, K. P.; Gross, C. J.; Miller, D.; Stracener, D. W.; Batchelder, J. C.; Brewer, N. T.; Cartegni, L.; Hamilton, J. H.; Hwang, J. K.; Liu, S. H.; Ilyushkin, S. V.; Jost, C.; Karny, M.; Korgul, A.; Królas, W.; Kuźniak, A.; Mazzocchi, C.; Mendez, A. J., II; Miernik, K.; Padgett, S. W.; Paulauskas, S. V.; Ramayya, A. V.; Winger, J. A.; Wolińska-Cichocka, M.; Zganjar, E. F.

      2012-09-01

      The β decays of neutron-rich nuclei near the doubly magic Ni78 were studied at the Holifield Radioactive Ion Beam Facility using an electromagnetic isobar separator. The half-lives of Zn82 (228±10ms), Zn83 (117±20ms), and Ga85 (93±7ms) were determined for the first time. These half-lives were found to be very different from the predictions of the global model used in astrophysical simulations. A new calculation was developed using the density functional model, which properly reproduced the new experimental values. The robustness of the new model in the Ni78 region allowed us to extrapolate data for more neutron-rich isotopes. The revised analysis of the rapid neutron capture process in low entropy environments with our new set of measured and calculated half-lives shows a significant redistribution of predicted isobaric abundances strengthening the yield of A>140 nuclei.

    5. Effects of simulated on-fire processing conditions on the microstructure and mechanical performance of Q345R steel

      NASA Astrophysics Data System (ADS)

      Peng, Yi-chao; Xu, Hao-hao; Zhang, Mai-cang

      2016-01-01

      A series of simulated on-fire processing experiments on Q345R steel plates was conducted, and the plates' Brinell hardness, tensile strength, and impact energy were tested. Microstructure morphologies were systematically analyzed using a scanning electron microscope with the aim of investigating the effect of the steel's microstructure on its performance. All examined performance parameters exhibited a substantial decrease in the cases of samples heat-treated at temperatures near 700°C. However, although the banded structure decreased with increasing treatment temperature and holding time, it had little effect on the performance decline in fact. Further analysis revealed that pearlite degeneration near 700°C, which was induced by the interaction of both subcritical annealing and conventional spherical annealing, was the primary reason for the degradation behavior. Consequently, some nonlinear mathematical models of different mechanical performances were established to facilitate processing adjustments.

    6. 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.

    7. Disruption of ribosome assembly in yeast blocks cotranscriptional pre-rRNA processing and affects the global hierarchy of ribosome biogenesis.

      PubMed

      Talkish, Jason; Biedka, Stephanie; Jakovljevic, Jelena; Zhang, Jingyu; Tang, Lan; Strahler, John R; Andrews, Philip C; Maddock, Janine R; Woolford, John L

      2016-06-01

      In higher eukaryotes, pre-rRNA processing occurs almost exclusively post-transcriptionally. This is not the case in rapidly dividing yeast, as the majority of nascent pre-rRNAs are processed cotranscriptionally, with cleavage at the A2 site first releasing a pre-40S ribosomal subunit followed by release of a pre-60S ribosomal subunit upon transcription termination. Ribosome assembly is driven in part by hierarchical association of assembly factors and r-proteins. Groups of proteins are thought to associate with pre-ribosomes cotranscriptionally during early assembly steps, whereas others associate later, after transcription is completed. Here we describe a previously uncharacterized phenotype observed upon disruption of ribosome assembly, in which normally late-binding proteins associate earlier, with pre-ribosomes containing 35S pre-rRNA. As previously observed by many other groups, we show that disruption of 60S subunit biogenesis results in increased amounts of 35S pre-rRNA, suggesting that a greater fraction of pre-rRNAs are processed post-transcriptionally. Surprisingly, we found that early pre-ribosomes containing 35S pre-rRNA also contain proteins previously thought to only associate with pre-ribosomes after early pre-rRNA processing steps have separated maturation of the two subunits. We believe the shift to post-transcriptional processing is ultimately due to decreased cellular division upon disruption of ribosome assembly. When cells are grown under stress or to high density, a greater fraction of pre-rRNAs are processed post-transcriptionally and follow an alternative processing pathway. Together, these results affirm the principle that ribosome assembly occurs through different, parallel assembly pathways and suggest that there is a kinetic foot-race between the formation of protein binding sites and pre-rRNA processing events. PMID:27036125

    8. The ATPase hCINAP regulates 18S rRNA processing and is essential for embryogenesis and tumour growth

      PubMed Central

      Bai, Dongmei; Zhang, Jinfang; Li, Tingting; Hang, Runlai; Liu, Yong; Tian, Yonglu; Huang, Dadu; Qu, Linglong; Cao, Xiaofeng; Ji, Jiafu; Zheng, Xiaofeng

      2016-01-01

      Dysfunctions in ribosome biogenesis cause developmental defects and increased cancer susceptibility; however, the connection between ribosome assembly and tumorigenesis remains unestablished. Here we show that hCINAP (also named AK6) is required for human 18S rRNA processing and 40S subunit assembly. Homozygous CINAP−/− mice show embryonic lethality. The heterozygotes are viable and show defects in 18S rRNA processing, whereas no delayed cell growth is observed. However, during rapid growth, CINAP haploinsufficiency impairs protein synthesis. Consistently, hCINAP depletion in fast-growing cancer cells inhibits ribosome assembly and abolishes tumorigenesis. These data demonstrate that hCINAP reduction is a specific rate-limiting controller during rapid growth. Notably, hCINAP is highly expressed in cancers and correlated with a worse prognosis. Genome-wide polysome profiling shows that hCINAP selectively modulates cancer-associated translatome to promote malignancy. Our results connect the role of hCINAP in ribosome assembly with tumorigenesis. Modulation of hCINAP expression may be a promising target for cancer therapy. PMID:27477389

    9. Treatment of log yard runoff using a r-circulating sand filtration process.

      PubMed

      Doig, P; Van Poppelen, P; Baldwin, S A

      2007-07-01

      A re-circulating filtration process using oxide-coated sand successfully removed COD and turbidity from log yard runoff. After passing only one pore volume of the runoff through the sand column, 72% COD was removed. The 2.4% Fe and Al oxide coating on the sand contributed to better COD removal than was obtained when the sand was stripped of oxide coating (86% versus 52%, respectively), at least initially before saturation of adsorption sites on the oxide coating occurred. The best COD removal performance came from conditioned sand. This sand, from the same original source and identical to the oxide-coated sand used in all experiments, came from an existing experimental sand column that had been treating log yard runoff for 1 year. The "conditioning" resulted in the sand having a higher TOC content (0.26% wt) and smaller particle sizes. This sand was able to consistently remove 80% COD from repeated batches of log yard runoff with strengths up to 3690 mg l(-1). PMID:17674655

    10. Daring the Challenge and Thinking Big: The Value of Early Process R&D.

      PubMed

      Abele, Stefan; Funel, Jacques-Alexis; Schmidt, Gunther; Moessner, Christian; Schwaninger, Mischa; Marti, Roger

      2016-01-01

      The production of the L/T channel blocker ACT-280778 required the enantiomerically pure 5-phenylbicyclo[2.2.2]oct-5-en-2-one (1) as key building block. As the published routes towards 1 are very low yielding (<0.5% yield) and comprise many steps that are not acceptable for scale-up, a series of processes to 1 was developed to match the increasing requirements from first kg-batches to clinical supplies. The three routes are characterized by an individual asset. (1) The first route contains a scale-up of a Diels-Alder reaction with highly reactive reagents and afforded 90 kg enantiomerically pure 1. To mitigate safety risks, a flow reactor was developed for the high-temperature Diels-Alder reaction. This route relied on an efficient enantiomer separation on a ¼-ton scale by HPLC. (2) A Crystallization Induced Diastereomer Transformation (CIDT) during an intramolecular aldol reaction was the pivotal step of a first enantioselective route that starts with the Shibasaki reaction. (3) The 2(nd) enantioselective route represents a rare example of organocatalysis on scale and allowed to skip six out of nine steps with a significant impact on the cost of goods. This simple way to 1 opened up a short synthesis of Hayashi's chiral diene ligands (bod*) that were so far lacking an affordable access. Some of these novel C1-symmetrical dienes have shown very high enantioselectivities in Rh-catalyzed additions of arylboronates. PMID:27561612

    11. 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.

    12. The origin and evolution of r- and s-process elements in the Milky Way stellar disk

      NASA Astrophysics Data System (ADS)

      Battistini, Chiara; Bensby, Thomas

      2016-02-01

      Context. Elements heavier than iron are produced through neutron-capture processes in the different phases of stellar evolution. Asymptotic giant branch (AGB) stars are believed to be mainly responsible for elements that form through the slow neutron-capture process, while the elements created in the rapid neutron-capture process have production sites that are less understood. Knowledge of abundance ratios as functions of metallicity can lead to insight into the origin and evolution of our Galaxy and its stellar populations. Aims: 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. This will allow us to constrain the formation sites of these elements, as well as to probe the evolution of the Galactic thin and thick disks. Methods: Using spectra of high resolution (42 000 ≲ R ≲ 65 000) and high signal-to-noise (S/N ≳ 200) obtained with the MIKE and the FEROS spectrographs, we determine Sr, Zr, La, Ce, Nd, Sm, and Eu abundances for a sample of 593 F and G dwarf stars in the solar neighborhood. The abundance analysis is based on spectral synthesis using one-dimensional, plane-parallel, local thermodynamic equilibrium (LTE) model stellar atmospheres calculated with the MARCS 2012 code. Results: We present abundance results for Sr (156 stars), Zr (311 stars), La (242 stars), Ce (365 stars), Nd (395 stars), Sm (280 stars), and Eu (378 stars). We find that Nd, Sm, and Eu show trends similar to what is observed for the α elements in the [X/Fe]-[Fe/H] abundance plane. For [Sr/Fe] and [Zr/Fe], we find 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, and they are close to solar values at all [Fe/H]. The trends of abundance ratios [X/Fe] as a function of stellar ages present different slopes before and after 8 Gyr. Conclusions: The rapid neutron-capture process is

    13. 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.

    14. Short-lived 244Pu points to compact binary mergers as sites for heavy r-process nucleosynthesis

      NASA Astrophysics Data System (ADS)

      Hotokezaka, Kenta; Piran, Tsvi; Paul, Michael

      2015-12-01

      The origin of heavy elements produced through rapid neutron capture (`r-process’) by seed nuclei is one of the current nucleosynthesis mysteries. Core collapse supernovae (cc-SNe; ref. ) and compact binary mergers are considered as possible sites. The first produces small amounts of material at a high event rate whereas the latter produces large amounts in rare events. Radioactive elements with the right lifetime can break the degeneracy between high-rate/low-yield and low-rate/high-yield scenarios. Among radioactive elements, most interesting is 244Pu (half-life of 81 million years), for which both the current accumulation of live 244Pu particles accreted via interstellar particles in the Earth’s deep-sea floor and the Early Solar System (ESS) abundances have been measured. Interestingly, the estimated 244Pu abundance in the current interstellar medium inferred from deep-sea measurements is significantly lower than that corresponding to the ESS measurements. Here we show that both the current and ESS abundances of 244Pu are naturally explained within the low-rate/high-yield scenario. The inferred event rate remarkably agrees with compact binary merger rates estimated from Galactic neutron star binaries and from short gamma-ray bursts. Furthermore, the ejected mass of r-process elements per event agrees with both theoretical and observational macronova/kilonova estimates.

    15. Beta-Decay Spectroscopy of r-Process Nuclei with N = 126 at KEK Isotope Separation System

      NASA Astrophysics Data System (ADS)

      Hirayama, Y.; Watanabe, Y. X.; Imai, N.; Ishiyama, H.; Jeong, S. C.; Miyatake, H.; Oyaizu, M.; Mukai, M.; Kimura, S.; Kim, Y. H.; Sonoda, T.; Wada, M.; Huyse, M.; Kudryavtsev, Yu.; Van Duppen, P.

      The β-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 β-decay properties, which are also of interest for astrophysics. We successfully extracted the stable 56Fe and 198Pt beam from KISS at the commissioning on-line experiments. The extraction efficiency was 0.25 and 0.15% for 56Fe and 198Pt, respectively. 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%.

    16. The Fuel Processing Research Facility - A Platform for the Conduct of Synthesis Gas Technology R&D

      SciTech Connect

      Monahan, Michael J.; Berry, David A.; Gardner, Todd H.; Lyons, K. David

      2001-11-06

      Vision 21 is the U. S. Department of Energy's initiative to deploy high efficiency, ultraclean co-production coal conversion power plants in the twenty-first century. These plants will consist of power and co-production modules, which are integrated to meet specific power and chemical markets. A variety of fuel gas processing technology issues involving gas separations, cleanup, gas-to-liquid fuels production and chemical synthesis, to mention a few, will be addressed by the program. The overall goal is to effectively eliminate, at competitive costs, environmental concerns associated with the use of fossil fuels for producing electricity and transportation fuels. The Fuel Processing Research Facility (FPRF) was developed as a fuel-flexible platform to address many of these technology needs. The facility utilizes a simplified syngas generator that is capable of producing 2,000 standard cubic feet per hour of 900 degree Celsius and 30 atmosphere synthesis gas that can be tailored to the gas composition of interest. It was built on a ''mid-scale'' level in an attempt to successfully branch the traditionally difficult scale-up from laboratory to pilot scale. When completed, the facility will provide a multi-faceted R&D area for the testing of fuel cells, gas separation technologies, and other gas processing unit operations.

    17. Shelf Edge Exchange Processes: 2, SEEP2-09, R/V ENDEAVOR cruise 193: Hydrographic data report

      SciTech Connect

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

      1990-01-01

      The R/V ENDEAVOR cruise 193, SEEP2-09, took place from 17--23 March 1989 and focused primarily on biological processes in the SEEP2 area. Mooring 1 was recovered and re-deployed and a replacement for mooring 4 was deployed. A 24 hour time series was conducted at mooring 1 to study primary and secondary production. The time series involved sampling nutrients, dissolved oxygen, chlorophyll {und a}, zooplankton abundance and distribution and fecal pellet production. Experiments to estimate grazing rates the fecal pellet production of the dominant copepods were also done. MOCNESS tows and box core samples were also taken during the cruise. Sediment and zooplankton data are not reported here. During this cruise 46 CTD casts were made measuring pressure, temperature, conductivity, dissolved oxygen, fluorescence and light transmission. Discrete samples were taken in rosette-mounted Niskin bottles and analyzed for concentration of nutrients, chlorophyll {und a}, dissolved oxygen, and particulate organic carbon and nitrogen.

    18. Large-scale B-spline R-matrix calculations of electron impact excitation and ionization processes in complex atoms

      NASA Astrophysics Data System (ADS)

      Zatsarinny, Oleg

      2013-09-01

      In recent years, the B-spline R-matrix (BSR) method has been applied to the treatment of a large number of atomic structure and electron-atom collision problems. Characteristic features of the BSR approach include the use of B-splines as a universal basis to describe the projectile electron inside the R-matrix box and the employment of term-dependent, and hence non-orthogonal, orbitals to construct the target states. The latter flexibility has proven to be of crucial importance for complex targets with several partially filled subshells. The published computer code has since been updated and extended to allow for a fully relativistic description at the level of the Dirac-Coulomb hamiltonian. Also, the systematic inclusion of a large number of pseudo-states in the close-coupling expansion has made it possible to extend the range of applicability from elastic and inelastic low-energy near-threshold phenomena to intermediate energies (up to several times the ionization threshold) and, in particular, to describe ionization processes as well. The basic ideas of the BSR approach will be reviewed, and its application will be illustrated for a variety of targets. Particular emphasis will be placed on systems of relevance for applications in gaseous electronics, such as the generation of complete datasets for electron collisions with the heavy noble gases Ne-Xe. Many of our data, which are needed for the description of transport processes in plasmas, are available through the LXCat database. This work was performed in collaboration with Klaus Bartschat. It is supported by the National Science Foundation under Grant No. PHY-1212450 and the XSEDE Allocation PHY-090031.

    19. THE BINARY FREQUENCY OF r-PROCESS-ELEMENT-ENHANCED METAL-POOR STARS AND ITS IMPLICATIONS: CHEMICAL TAGGING IN THE PRIMITIVE HALO OF THE MILKY WAY

      SciTech Connect

      Hansen, Terese; Andersen, Johannes; Nordstroem, Birgitta; Buchhave, Lars A.; Beers, Timothy C. E-mail: ja@astro.ku.dk E-mail: beers@pa.msu.edu

      2011-12-10

      A few rare halo giants in the range [Fe/H] {approx_equal} -2.9 {+-} 0.3 exhibit r-process element abundances that vary as a group by factors up to [r/Fe] {approx}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.

    20. 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...

    1. The loop structure and the RNA helicase p72/DDX17 influence the processing efficiency of the mice miR-132

      PubMed Central

      Remenyi, Judit; Bajan, Sarah; Fuller-Pace, Frances V.; Arthur, J. Simon C.; Hutvagner, Gyorgy

      2016-01-01

      miRNAs are small RNAs that are key regulators of gene expression in eukaryotic organisms. The processing of miRNAs is regulated by structural characteristics of the RNA and is also tightly controlled by auxiliary protein factors. Among them, RNA binding proteins play crucial roles to facilitate or inhibit miRNA maturation and can be controlled in a cell, tissue and species-specific manners or in response to environmental stimuli. In this study we dissect the molecular mechanism that promotes the overexpression of miR-132 in mice over its related, co-transcribed and co-regulated miRNA, miR-212. We have shown that the loop structure of miR-132 is a key determinant for its efficient processing in cells. We have also identified a range of RNA binding proteins that recognize the loop of miR-132 and influence both miR-132 and miR-212 processing. The DEAD box helicase p72/DDX17 was identified as a factor that facilitates the specific processing of miR-132. PMID:26947125

    2. The loop structure and the RNA helicase p72/DDX17 influence the processing efficiency of the mice miR-132.

      PubMed

      Remenyi, Judit; Bajan, Sarah; Fuller-Pace, Frances V; Arthur, J Simon C; Hutvagner, Gyorgy

      2016-01-01

      miRNAs are small RNAs that are key regulators of gene expression in eukaryotic organisms. The processing of miRNAs is regulated by structural characteristics of the RNA and is also tightly controlled by auxiliary protein factors. Among them, RNA binding proteins play crucial roles to facilitate or inhibit miRNA maturation and can be controlled in a cell, tissue and species-specific manners or in response to environmental stimuli. In this study we dissect the molecular mechanism that promotes the overexpression of miR-132 in mice over its related, co-transcribed and co-regulated miRNA, miR-212. We have shown that the loop structure of miR-132 is a key determinant for its efficient processing in cells. We have also identified a range of RNA binding proteins that recognize the loop of miR-132 and influence both miR-132 and miR-212 processing. The DEAD box helicase p72/DDX17 was identified as a factor that facilitates the specific processing of miR-132. PMID:26947125

    3. Explosive Nucleosynthesis of Weak R-Process Elements in Extremely Metal-Poor Core-Collapse Supernovae

      NASA Astrophysics Data System (ADS)

      Izutani, Natsuko; Umeda, Hideyuki; Tominaga, Nozomu

      2009-02-01

      There have been attempts to fit the abundance patterns of extremely metal-poor (EMP) stars with supernova (SN) nucleosynthesis models for the elements lighter than Zn. Observations have revealed the presence of EMP stars with a peculiarly high ratio of "weak r-process elements" Sr, Y, and Zr. Although several possible processes were suggested for the origin of these elements, a complete solution for reproducing those ratios has not yet been found. 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 SN (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 SN. Our results imply that, if these elements are ejected from a normal SN, nucleosynthesis in higher entropy flow than that of the SN shock is required.

    4. 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.

    5. 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.

    6. 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 β-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 β-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.

    7. Large-scale evaluation of β -decay rates of r -process nuclei with the inclusion of first-forbidden transitions

      NASA Astrophysics Data System (ADS)

      Marketin, T.; Huther, L.; Martínez-Pinedo, G.

      2016-02-01

      Background: r -process nucleosynthesis models rely, by necessity, on nuclear structure models for input. Particularly important are β -decay half-lives of neutron-rich nuclei. At present only a single systematic calculation exists that provides values for all relevant nuclei making it difficult to test the sensitivity of nucleosynthesis models to this input. Additionally, even though there are indications that their contribution may be significant, the impact of first-forbidden transitions on decay rates has not been systematically studied within a consistent model. Purpose: Our goal is to provide a table of β -decay half-lives and β -delayed neutron emission probabilities, including first-forbidden transitions, calculated within a fully self-consistent microscopic theoretical framework. The results are used in an r -process nucleosynthesis calculation to asses the sensitivity of heavy element nucleosynthesis to weak interaction reaction rates. Method: We use a fully self-consistent covariant density functional theory (CDFT) framework. The ground state of all nuclei is calculated with the relativistic Hartree-Bogoliubov (RHB) model, and excited states are obtained within the proton-neutron relativistic quasiparticle random phase approximation (p n -RQRPA). Results: The β -decay half-lives, β -delayed neutron emission probabilities, and the average number of emitted neutrons have been calculated for 5409 nuclei in the neutron-rich region of the nuclear chart. We observe a significant contribution of the first-forbidden transitions to the total decay rate in nuclei far from the valley of stability. The experimental half-lives are in general well reproduced for even-even, odd-A , and odd-odd nuclei, in particular for short-lived nuclei. The resulting data table is included with the article as Supplemental Material. Conclusions: In certain regions of the nuclear chart, first-forbidden transitions constitute a large fraction of the total decay rate and must be

    8. EXTREME ENHANCEMENTS OF r-PROCESS ELEMENTS IN THE COOL METAL-POOR MAIN-SEQUENCE STAR SDSS J2357-0052

      SciTech Connect

      Aoki, Wako; Beers, Timothy C.; Honda, Satoshi; Carollo, Daniela E-mail: beers@pa.msu.ed E-mail: carollo@mso.anu.edu.a

      2010-11-10

      We report the discovery of a cool metal-poor, main-sequence star exhibiting large excesses of r-process elements. This star is one of the two newly discovered cool subdwarfs (effective temperatures of 5000 K) with extremely low metallicity ([Fe/H] < -3) identified from follow-up high-resolution spectroscopy of metal-poor candidates from the Sloan Digital Sky Survey. SDSS J2357-0052 has [Fe/H] = -3.4 and [Eu/Fe] = +1.9, and exhibits a scaled solar r-process abundance pattern of heavy neutron-capture elements. This is the first example of an extremely metal-poor, main-sequence star showing large excesses of r-process elements; all previous examples of the large r-process-enhancement phenomena have been associated with metal-poor giants. The metallicity of this object is the lowest, and the excess of Eu ([Eu/Fe]) is the highest, among the r-process-enhanced stars found so far. We consider possible scenarios to account for the detection of such a star and discuss techniques to enable searches for similar stars in the future.

    9. Preparation and modification of VO2 thin film on R-sapphire substrate by rapid thermal process

      NASA Astrophysics Data System (ADS)

      Zhu, Nai-Wei; Hu, Ming; Xia, Xiao-Xu; Wei, Xiao-Ying; Liang, Ji-Ran

      2014-04-01

      The VO2 thin film with high performance of metal-insulator transition (MIT) is prepared on R-sapphire substrate for the first time by magnetron sputtering with rapid thermal process (RTP). The electrical characteristic and THz transmittance of MIT in VO2 film are studied by four-point probe method and THz time domain spectrum (THz-TDS). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and search engine marketing (SEM) are employed to analyze the crystalline structure, valence state, surface morphology of the film. Results indicate that the properties of VO2 film which is oxidized from the metal vanadium film in oxygen atmosphere are improved with a follow-up RTP modification in nitrogen atmosphere. The crystallization and components of VO2 film are improved and the film becomes compact and uniform. A better phase transition performance is shown that the resistance changes nearly 3 orders of magnitude with a 2-°C hysteresis width and the THz transmittances are reduced by 64% and 60% in thermal and optical excitation respectively.

    10. 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.

    11. Microbial succession in the traditional Chinese Luzhou-flavor liquor fermentation process as evaluated by SSU rRNA profiles.

      PubMed

      Xiang, Wenliang; Li, Ke; Liu, Seng; Xing, Yage; Li, Mingyuan; Che, Zhenming

      2013-03-01

      The community succession of microbes inhabited in the fermenting lees of Luzhou-flavor liquor was investigated based on small-subunit rRNA culture independent method. All sequences recovered from fermenting lees respectively fell into the genera of Lactobacillus, Streptococcus, Bacillus, Staphylococcus, Clostridium, Pelobacter, Actobacter, Serratia, Burkholderia, Rhodoccous, Corynebacterium, Arthrobacter, Microbacterium, Curtobacterium, Leptotrichia, Methanocuuleus, Saccharomyces, Zygosaccharomyces, Saccharomycopsis, Pichia, Talaromyces, Aspergillus, Eurotium, Fomitopsis and Trichosporon. The fungal Pichia, Saccharomycopsis and Talaromyces were most abundant in the lees fermented for 1 day, the fungal Eurotium and the bacteria Burkholderia, Streptococcus and Lactobacillus were dominant in the lees fermented for 7 days, only the bacteria Lactobacillus, Burkholderia were prevalent in the lees fermented for 60 days. Most genera almost existed in the fermenting lees, while their distributions were significantly different in 1, 7 and 60 days fermented lees. The prokaryotic community similarity coefficient was from 0.5000 to 0.5455 and followed to 0.1523, and that of eukaryotic community was from 0.5466 to 0.5259 and to 0.3750 when compared at species level. These results suggested that many microbes in lees have community successions associated with fermenting and that such successions maybe contribute the fermentation process of Luzhou-flavor liquor and is main reasons that the characteristic flavor factors are produced. PMID:23180546

    12. Mutant p53 induces EZH2 expression and promotes epithelial–mesenchymal transition by disrupting p68-Drosha complex assembly and attenuating miR-26a processing

      PubMed Central

      Wang, Hui-Hui; Zhang, Hui-Lin; Zhang, Jian; Yan, Xiao-Fang; Wang, Xiao-Jun; Che, Qi; Ke, Jie-Qi; Chen, Zheng; Tong, Huan; Zhang, Yong-Li; Wang, Fang-Yuan; Li, Yi-Ran; Wan, Xiao-Ping

      2015-01-01

      The tumor suppressor p53 and the transcriptional repressor Enhancer of Zeste Homolog 2 (EZH2) have both been implicated in the regulation of epithelial-mesenchymal transition (EMT) and tumor metastasis via their impacts on microRNA expression. Here, we report that mutant p53 (mutp53) promotes EMT in endometrial carcinoma (EC) by disrupting p68-Drosha complex assembly. Overexpression of mutp53 has the opposite effect of wild-type p53 (WTp53), repressing miR-26a expression by reducing pri-miR-26a-1 processing in p53-null EC cells. Re-expression of miR-26a in mutp53 EC cells decreases cell invasion and promotes mesenchymal-epithelial transition (MET). Rescuing miR-26a expression also inhibits EZH2, N-cadherin, Vimentin, and Snail expression and induces E-cadherin expression both in vitro and in vivo. Moreover, patients with higher serum miR-26a levels have a better survival rate. These results suggest that p53 gain-of-function mutations accelerate EC tumor progression and metastasis by interfering with Drosha and p68 binding and pri-miR-26a-1 processing, resulting in reduced miR-26a expression and EZH2 overexpression. PMID:26587974

    13. 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-β (TGF-β) induces miR-21 expression which contributes to fibrotic events in the left ventricle (LV) under pressure overload. SMAD effectors of TGF-β 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-β1 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-β1, SMAD2 and SMAD3. In the LV from AS patients, DICER mRNA was up-regulated and its transcript levels correlated directly with TGF-β1, 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 TGFβ-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

    14. [Montérégie Comprehensive Cancer Care Centre: integrating nurse navigators in Montérégie's oncology teams: the process. Part 2].

      PubMed

      Plante, Anne; Joannette, Sonia

      2009-01-01

      Quebec's Oncology Nurse Navigators (or "IPOs" after their French acronym) have been integrated in the entire Montérégie health care region. They have been agents of change mandated with implementing a philosophy of care that centres on the patients and their families, and is delivered by oncology teams. The goal of this second article is to describe the role of IPOs in practice, the problems encountered in the various contexts and the solutions brought forward to facilitate their integration. The training of IPOs, the support they receive from administrators, the deployment of interdisciplinary teams dedicated to oncology, the holding of regular structured interdisciplinary meetings and the training of professionals, and development of standardized work instruments are discussed. The observed impacts of introducing IPOs will also be examined. PMID:19757765

    15. 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 6σ (5σ) confidence; the 27.3 keV line complex of 125Sb is detectable by NuSTAR at 2σ 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.

    16. Theoretical uncertainty of (α ,n ) reactions relevant for the nucleosynthesis of light r -process nuclei in neutrino-driven winds

      NASA Astrophysics Data System (ADS)

      Pereira, J.; Montes, F.

      2016-03-01

      Background: Neutrino-driven winds following core-collapse supernova explosions have been proposed as a possible site where light r -process nuclei (between Fe and Ag) might be synthesized. In these events, (α ,n ) reactions are key to moving matter towards the region of higher proton number. Abundance network calculations are very sensitive to the rates for this type of reactions. Purpose: The present work aims at evaluating the theoretical uncertainty of these (α ,n ) reactions calculated with reaction codes based on the Hauser-Feshbach model. Method: We compared several (α ,n ) rates taken from talys and the non-smoker database to determine the uncertainties owing to the existing technical differences between both codes. In addition, we evaluated the sensitivity of talys rates to variations in the α optical potentials, masses, level densities, optical potentials, preequilibrium intranuclear transition rates, level structure, radiative transmission coefficients, and width-fluctuation correction factors. Results: The main source of uncertainty at low temperature is mostly attributable to the use of different α optical potentials. Differences between talys and non-smoker at high temperatures arise from the energy-binning algorithm used by each code. We have also noticed that the (α ,n ) rates from the non-smoker database correspond to the inclusive reaction, instead of the exclusive (α ,1 n ) channel calculated in the present work and used in network calculations. Conclusions: Theoretical uncertainties in calculated reaction rates can be as high as one to two orders of magnitude and strongly dependent on the temperature of the environment. Besides direct measurements of the inclusive and exclusive (α ,1 n ) reaction rates, experimental studies of α optical potentials are crucial to improve the performance of reaction codes.

    17. 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.

    18. A plant snoRNP complex containing snoRNAs, fibrillarin, and nucleolin-like proteins is competent for both rRNA gene binding and pre-rRNA processing in vitro.

      PubMed

      Sáez-Vasquez, Julio; Caparros-Ruiz, David; Barneche, Fredy; Echeverría, Manuel

      2004-08-01

      In eukaryotes the primary cleavage of the precursor rRNA (pre-rRNA) occurs in the 5' external transcribed spacer (5'ETS). In Saccharomyces cerevisiae and animals this cleavage depends on a conserved U3 small nucleolar ribonucleoprotein particle (snoRNP), including fibrillarin, and on other transiently associated proteins such as nucleolin. This large complex can be visualized by electron microscopy bound to the nascent pre-rRNA soon after initiation of transcription. Our group previously described a radish rRNA gene binding activity, NF D, that specifically binds to a cluster of conserved motifs preceding the primary cleavage site in the 5'ETS of crucifer plants including radish, cauliflower, and Arabidopsis thaliana (D. Caparros-Ruiz, S. Lahmy, S. Piersanti, and M. Echeverria, Eur. J. Biochem. 247:981-989, 1997). Here we report the purification and functional characterization of NF D from cauliflower inflorescences. Remarkably NF D also binds to 5'ETS RNA and accurately cleaves it at the primary cleavage site mapped in vivo. NF D is a multiprotein factor of 600 kDa that dissociates into smaller complexes. Two polypeptides of NF D identified by microsequencing are homologues of nucleolin and fibrillarin. The conserved U3 and U14 snoRNAs associated with fibrillarin and required for early pre-rRNA cleavages are also found in NF D. Based on this it is proposed that NF D is a processing complex that assembles on the rDNA prior to its interaction with the nascent pre-rRNA. PMID:15282326

    19. The s-process in low-metallicity stars - III. Individual analysis of CEMP-s and CEMP-s/r with asymptotic giant branch models

      NASA Astrophysics Data System (ADS)

      Bisterzo, S.; Gallino, R.; Straniero, O.; Cristallo, S.; Käppeler, F.

      2012-05-01

      We provide an individual analysis of 94 carbon-enhanced metal-poor stars showing an s-process enrichment (CEMP-s) collected from the literature. The s-process enhancement observed in these stars is ascribed to mass transfer by stellar winds in a binary system from a more massive companion evolving faster towards the asymptotic giant branch (AGB) phase. The theoretical AGB nucleosynthesis models have been presented in Bisterzo et al. (Paper I of this series). Several CEMP-s show an enhancement in both s- and r-process elements (CEMP-s/r). In order to explain the peculiar abundances observed in CEMP-s/r, we assume that the molecular cloud from which CEMP-s formed was previously enriched in r-elements by supernova pollution. A general discussion and the method adopted in order to interpret the observations have been provided in Bisterzo et al. (Paper II of this series). We present in this paper a detailed study of spectroscopic observations of individual stars. We consider all elements from carbon to bismuth, with particular attention to the three s-process peaks, ls (Y, Zr), hs (La, Nd, Sm) and Pb, and their ratios [hs/ls] and [Pb/hs]. The presence of an initial r-process contribution may be typically evaluated by [La/Eu]. We found possible agreements between theoretical predictions and spectroscopic data. In general, the observed [Na/Fe] (and [Mg/Fe]) provides information on the AGB initial mass, while [hs/ls] and [Pb/hs] are mainly indicators of the s-process efficiency. A range of 13C-pocket strengths are required to interpret the observations. However, major discrepancies between models and observations exist. We highlight star by star the agreements and the main problems encountered and, when possible, we suggest potential indications for further studies. These discrepancies provide starting points of debate for unsolved problems in which spectroscopic and theoretical studies may intervene.

    20. β decay of nuclei around 90Se: Search for signatures of a N=56 subshell closure relevant to the r process

      NASA Astrophysics Data System (ADS)

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

      2012-03-01

      Background: Nuclear structure plays a significant role on the rapid neutron capture process (r process) since shapes evolve with the emergence of shells and subshells. There was some indication in neighboring nuclei that we might find examples of a new N=56 subshell, which may give rise to a doubly magic 3490Se56 nucleus.Purpose: β-decay half-lives of nuclei around 90Se have been measured to determine if this nucleus has in fact a doubly magic character.Method: The fragmentation of a 136Xe beam at the National Superconducting Cyclotron Laboratory at Michigan State University was used to create a cocktail of nuclei in the A=90 region.Results: We have measured the half-lives of 22 nuclei near the r-process path in the A=90 region. The half-lives of 88As and 90Se 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 subshell, and its possible role in the emergence of a potential doubly magic 90Se. 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.Conclusions: The new half-lives agree with results obtained from a standard global QRPA model used in r-process calculations, indicating that 90Se has a quadrupole shape incompatible with a closed N=56 subshell in this region. The impact of the measured 90Se 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.

    1. 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…

    2. Corrigendum to "The impact of individual nuclear properties on r-process nucleosynthesis" [J. Prog. Part. Nucl. Phys. 86C (2015) 86-126

      NASA Astrophysics Data System (ADS)

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

      2016-03-01

      The authors regret that the scale of the far right axis of Fig. 1 was incorrect. The scale of the far right axis of Fig. 1, indicating the evolution of density with time for a cold r-process trajectory, has been corrected. There is no change to the figure caption.

    3. NVL2, a nucleolar AAA-ATPase, is associated with the nuclear exosome and is involved in pre-rRNA processing

      SciTech Connect

      Yoshikatsu, Yuki; Ishida, Yo-ichi; Sudo, Haruka; Yuasa, Keizo; Tsuji, Akihiko; Nagahama, Masami

      2015-08-28

      Nuclear VCP-like 2 (NVL2) is a member of the chaperone-like AAA-ATPase family and is involved in the biosynthesis of 60S ribosomal subunits in mammalian cells. We previously showed the interaction of NVL2 with a DExD/H-box RNA helicase MTR4/DOB1, which is a known cofactor for an exoribonuclease complex, the exosome. This finding implicated NVL2 in RNA metabolic processes during ribosome biogenesis. In the present study, we found that a series of mutations within the ATPase domain of NVL2 causes a defect in pre-rRNA processing into mature 28S and 5.8S rRNAs. Co-immunoprecipitation analysis showed that NVL2 was associated with the nuclear exosome complex, which includes RRP6 as a nucleus-specific catalytic subunit. This interaction was prevented by depleting either MTR4 or RRP6, indicating their essential role in mediating this interaction with NVL2. Additionally, knockdown of MPP6, another cofactor for the nuclear exosome, also prevented the interaction by causing MTR4 to dissociate from the nuclear exosome. These results suggest that NVL2 is involved in pre-rRNA processing by associating with the nuclear exosome complex and that MPP6 is required for maintaining the integrity of this rRNA processing complex. - Highlights: • ATPase-deficient mutants of NVL2 have decreased pre-rRNA processing. • NVL2 associates with the nuclear exosome through interactions with MTR4 and RRP6. • MPP6 stabilizes MTR4-RRP6 interaction and allows NVL2 to interact with the complex.

    4. Escherichia coli cafA gene encodes a novel RNase, designated as RNase G, involved in processing of the 5' end of 16S rRNA.

      PubMed

      Wachi, M; Umitsuki, G; Shimizu, M; Takada, A; Nagai, K

      1999-06-01

      We found that the Escherichia coli cafA::cat mutant accumulated a precursor of 16S rRNA. This precursor migrated to the same position with 16.3S precursor found in the BUMMER strain that is known to be deficient in the 5' end processing of 16S rRNA. Accumulation of 16. 3S rRNA in the BUMMER mutant was complemented by introduction of a plasmid carrying the cafA gene. The mutant type cafA gene cloned from the BUMMER strain had a 11-bp deletion in its coding region. A small amount of the mature 16S rRNA was still formed in the cafA::cat mutant. This residual activity was found to be due to RNase E encoded by the rne/ams gene by rifampicin-chase experiments of the cafA::cat ams1 double mutant. These results indicated that the cafA gene encodes a novel RNase responsible for processing of the 5' end of 16S rRNA. PMID:10362534

    5. miR-124-regulated RhoG reduces neuronal process complexity via ELMO/Dock180/Rac1 and Cdc42 signalling

      PubMed Central

      Franke, Kristin; Otto, Wolfgang; Johannes, Sascha; Baumgart, Jan; Nitsch, Robert; Schumacher, Stefan

      2012-01-01

      The small GTPase RhoG plays a central role in actin remodelling during diverse biological processes such as neurite outgrowth, cell migration, phagocytosis of apoptotic cells, and the invasion of pathogenic bacteria. Although it is known that RhoG stimulates neurite outgrowth in the rat pheochromocytoma PC12 cell line, neither the physiological function nor the regulation of this GTPase in neuronal differentiation is clear. Here, we identify RhoG as an inhibitor of neuronal process complexity, which is regulated by the microRNA miR-124. We find that RhoG inhibits dendritic branching in hippocampal neurons in vitro and in vivo. RhoG also inhibits axonal branching, acting via an ELMO/Dock180/Rac1 signalling pathway. However, RhoG inhibits dendritic branching dependent on the small GTPase Cdc42. Finally, we show that the expression of RhoG in neurons is suppressed by the CNS-specific microRNA miR-124 and connect the regulation of RhoG expression by miR-124 to the stimulation of neuronal process complexity. Thus, RhoG emerges as a cellular conductor of Rac1 and Cdc42 activity, in turn regulated by miR-124 to control axonal and dendritic branching. PMID:22588079

    6. miR-124-regulated RhoG reduces neuronal process complexity via ELMO/Dock180/Rac1 and Cdc42 signalling.

      PubMed

      Franke, Kristin; Otto, Wolfgang; Johannes, Sascha; Baumgart, Jan; Nitsch, Robert; Schumacher, Stefan

      2012-06-29

      The small GTPase RhoG plays a central role in actin remodelling during diverse biological processes such as neurite outgrowth, cell migration, phagocytosis of apoptotic cells, and the invasion of pathogenic bacteria. Although it is known that RhoG stimulates neurite outgrowth in the rat pheochromocytoma PC12 cell line, neither the physiological function nor the regulation of this GTPase in neuronal differentiation is clear. Here, we identify RhoG as an inhibitor of neuronal process complexity, which is regulated by the microRNA miR-124. We find that RhoG inhibits dendritic branching in hippocampal neurons in vitro and in vivo. RhoG also inhibits axonal branching, acting via an ELMO/Dock180/Rac1 signalling pathway. However, RhoG inhibits dendritic branching dependent on the small GTPase Cdc42. Finally, we show that the expression of RhoG in neurons is suppressed by the CNS-specific microRNA miR-124 and connect the regulation of RhoG expression by miR-124 to the stimulation of neuronal process complexity. Thus, RhoG emerges as a cellular conductor of Rac1 and Cdc42 activity, in turn regulated by miR-124 to control axonal and dendritic branching. PMID:22588079

    7. 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...

    8. Exploring the Interrelationship of Structure and Process in Family Child Care: The FCCERS-R and "Combined" CLASS

      ERIC Educational Resources Information Center

      Enns, Lionel

      2012-01-01

      This study examined the correlations between two prominent family child care environmental rating scales, the Family Child Care Environment Rating Scale - Revised (FCCERS-R) and the "Combined" Classroom Assessment Scoring System ("Combined" CLASS), both of which were used during the pilot study of Washington State's…

    9. Laser Remote Measurements of atmospheric pollutants (Las-R-Map): UV-Visible Laser system description and data processing

      NASA Astrophysics Data System (ADS)

      Sivakumar, V.; Wyk, H. V.

      Laser radar more popularly known as LIDAR LIght Detection And Ranging is becoming one of the most powerful techniques for active remote sensing of the earth s atmosphere Around the globe several new lidar systems have been developed based on the scientific interest Particularly the DIfferential Absorption Lidar DIAL technique is only one which can provide the better accuracy of measuring atmospheric pollutants Using modern advanced techniques and instrumentation a mobile DIAL system called laser remote measurements of atmospheric pollutants hear after referred as Las-R-Map is designed at National Laser Centre NLC --Pretoria 25 r 45 prime S 28 r 17 prime E Las-R-Map is basically used for measuring atmospheric pollutants applying the principle of absorption by constituents The system designed primarily to focus on the following pollutant measurements such as SO 2 CH 4 CO 2 NO 2 and O 3 In future the system could be used to measure few particulate matter between 2 5 mu m and 10 mu m Benzene Hg 1 3-butadiene H 2 S HF and Volatile Organic Compounds VOC Las-R-map comprises of two different laser sources Alexandrite and CO 2 optical receiver data acquisition and signal processor It uses alexandrite laser in the UV-Visible region from 200 nm to 800 nm and CO 2 laser in the Far-IR region from 9 2 mu m to 10 8 mu m Such two different laser sources make feasibility for studying the wide range of atmospheric pollutants The present paper is focused on technical details

    10. An autoregulatory network between menin and pri-miR-24-1 is required for the processing of its specific modulator miR-24-1 in BON1 cells.

      PubMed

      Luzi, Ettore; Marini, Francesca; Ciuffi, Simone; Galli, Gianna; Brandi, Maria Luisa

      2016-05-24

      Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary cancer complex syndrome manifesting a variety of endocrine and non-endocrine neoplasms and lesions. MEN1 is characterized by tumours of the parathyroids, of the neuroendocrine cells of the gastroenteropancreatic tract, and of the anterior pituitary. The MEN1 gene, a tumour suppressor gene, encodes the menin protein. Loss of heterozygosity (LOH) at 11q13 is typical of MEN1 tumours in agreement with Knudson's two-hit hypothesis. We previously showed that the MEN1 parathyroid tumorigenesis is under the control of an "incoherent feedback loop" between miR-24-1 and the menin protein that generates a "Gene Regulatory Network" (GRN) that mimics the second hit of Knudson's hypothesis and that could buffer the effect of the stochastic factors that contribute to the onset and progression of this disease. Here we show, in the BON1 cell line derived from lymphnode metastasis of a human carcinoid tumour of the pancreas, that menin binds specifically to the primary RNA sequence pri-miR-24-1 by promoting the miR-24-1 biogenesis. Network simulation showed a new feed-forward loop between menin, microRNA-24-1 and Musashi-1 proteins. This result shows a novel mechanism whereby menin, a RNA-binding protein, facilitates the processing of its specific miRNA by regulating the dynamics of the menin-miR-24 Gene Regulatory Network at the level of pri-miRNA processing. PMID:27098433

    11. Half-lives and branchings for β-delayed neutron emission for neutron-rich Co-Cu isotopes in the r-process

      NASA Astrophysics Data System (ADS)

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

      2010-08-01

      The β decays of very neutron-rich nuclides in the Co-Zn region were studied experimentally at the National Superconducting Cyclotron Laboratory using the NSCL β-counting station in conjunction with the neutron detector NERO. We measured the branchings for β-delayed neutron emission (Pn values) for Co74 (18±15%) and Ni75-77 (10±2.8%, 14±3.6%, and 30±24%, respectively) for the first time, and remeasured the Pn values of Cu77-79, Zn79,81, and Ga82. For Cu77-79 and for Zn81 we obtain significantly larger Pn 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 Co75 (30±11 ms) and Cu80 (170-50+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.

    12. Mycobacterium bovis BCG Interferes with miR-3619-5p Control of Cathepsin S in the Process of Autophagy

      PubMed Central

      Pawar, Kamlesh; Sharbati, Jutta; Einspanier, Ralf; Sharbati, Soroush

      2016-01-01

      Main survival mechanism of pathogenic mycobacteria is to escape inimical phagolysosomal environment inside the macrophages. Many efforts have been made to unravel the molecular mechanisms behind this process. However, little is known about the involvement of microRNAs (miRNAs) in the regulation of phagolysosomal biosynthesis and maturation. Based on a bottom up approach, we searched for miRNAs that were involved in phagolysosomal processing events in the course of mycobacterial infection of macrophages. After infecting THP-1 derived macrophages with viable and heat killed Mycobacterium bovis BCG (BCG), early time points were identified after co-localization studies of the phagosomal marker protein LAMP1 and BCG. Differences in LAMP1 localization on the phagosomes of both groups were observed at 30 min and 4 h. After in silico based pre-selection of miRNAs, expression analysis at the identified time points revealed down-regulation of three miRNAs: miR-3619-5p, miR-637, and miR-324-3p. Consequently, most likely targets were predicted that were supposed to be mutually regulated by these three studied miRNAs. The lysosomal cysteine protease Cathepsin S (CTSS) and Rab11 family-interacting protein 4 (RAB11FIP4) were up-regulated and were considered to be connected to lysosomal trafficking and autophagy. Interaction studies verified the regulation of CTSS by miR-3619-5p. Down-regulation of CTSS by ectopic miR-3619-5p as well as its specific knockdown by siRNA affected the process of autophagy in THP-1 derived macrophages. PMID:27014637

    13. Approaches to pre-formulation R and D for phytopharmaceuticals emanating from herb based traditional Ayurvedic processes

      PubMed Central

      Anantha, Narayana D. B.

      2013-01-01

      Botanicals constitute a large part of the drugs from the traditional medicine (TM) and ethno medicine (EM) known for their history of safe use (HOSU). Phytopharmaceuticals having a base of such origin offer high advantages as they come with safety profiles, and often allow extrapolation of the HOSU data, under certain circumstances. However, while current pharmaceutical technologies are being adopted by the industry to make phytopharmaceuticals with such origin, there is a need for preformulation research and development (R and D) during formulation. Some suggestions for R and D studies in case of aqueous extracts known in Ayurveda, converted on an industrial scale to obtain a phytopharmaceutical, and formulated as a solid dosage form (granules, tablets, or capsules) are discussed. PMID:23741154

    14. 13,14B(n, γ) via Coulomb Dissociation for Nucleosynthesis towards the r-Process

      NASA Astrophysics Data System (ADS)

      Altstadt, S. G.; Adachi, T.; Aksyutina, Y.; Alcantara, J.; Alvarez-Pol, H.; Ashwood, N.; Atar, L.; Aumann, T.; Avdeichikov, V.; Barr, M.; Beceiro, S.; Bemmerer, D.; Benlliure, J.; Bertulani, C. A.; Boretzky, K.; Borge, M. J. G.; Burgunder, G.; Caamano, M.; Caesar, C.; Casarejos, E.; Catford, W.; Cederkäll, J.; Chakraborty, S.; Chartier, M.; Chulkov, L.; Cortina-Gil, D.; Datta Pramanik, U.; Diaz Fernandez, P.; Dillmann, I.; Elekes, Z.; Enders, J.; Ershova, O.; Estrade, A.; Farinon, F.; Fraile, L. M.; Freer, M.; Freudenberger, M.; Fynbo, H. O. U.; Galaviz, D.; Geissel, H.; Gernhäuser, R.; Göbel, K.; Golubev, P.; Gonzalez Diaz, D.; Hagdahl, J.; Heftrich, T.; Heil, M.; Heine, M.; Heinz, A.; Henriques, A.; Holl, M.; Holt, J. D.; Ickert, G.; Ignatov, A.; Jakobsson, B.; Johansson, H. T.; Jonson, B.; Kalantar-Nayestanaki, N.; Kanungo, R.; Kelic-Heil, A.; Knöbel, R.; Kröll, T.; Krücken, R.; Kurcewicz, J.; Kurz, N.; Labiche, M.; Langer, C.; Le Bleis, T.; Lemmon, R.; Lepyoshkina, O.; Machado, J.; Marganiec, J.; Maroussov, V.; Menéndez, J.; Mostazo, M.; Movsesyan, A.; Najafi, M. A.; Nilsson, T.; Nociforo, C.; Panin, V.; Perea, A.; Pietri, S.; Plag, R.; Prochazka, A.; Rahaman, A.; Rastrepina, G.; Reifarth, R.; Ribeiro, G.; Ricciardi, M. V.; Rigollet, C.; Riisager, K.; Röder, M.; Rossi, D.; Sanchez del Rio, J.; Savran, D.; Scheit, H.; Schwenk, A.; Simon, H.; Simonis, J.; Sonnabend, K.; Sorlin, O.; Stoica, V.; Streicher, B.; Taylor, J.; Tengblad, O.; Terashima, S.; Thies, R.; Togano, Y.; Uberseder, E.; Van de Walle, J.; Velho, P.; Volkov, V.; Wagner, A.; Wamers, F.; Weick, H.; Weigand, M.; Wheldon, C.; Wilson, G.; Wimmer, C.; Winfield, J. S.; Woods, P.; Yakorev, D.; Zhukov, M. V.; Zilges, A.; Zoric, M.; Zuber, K.

      2014-06-01

      Radioactive beams of 14,15B produced by fragmentation of a primary 40Ar beam were directed onto a Pb target to investigate the neutron breakup within the Coulomb field. The experiment was performed at the LAND/R3B setup. Preliminary results for the Coulomb dissociation cross sections as well as for the astrophysically interesting inverse reactions, 13,14B(n,γ), are presented.

    15. Aggregation of Ribosomal Protein S6 at Nucleolus Is Cell Cycle-Controlled and Its Function in Pre-rRNA Processing Is Phosphorylation Dependent.

      PubMed

      Zhang, Duo; Chen, Hui-Peng; Duan, Hai-Feng; Gao, Li-Hua; Shao, Yong; Chen, Ke-Yan; Wang, You-Liang; Lan, Feng-Hua; Hu, Xian-Wen

      2016-07-01

      Ribosomal protein S6 (rpS6) has long been regarded as one of the primary r-proteins that functions in the early stage of 40S subunit assembly, but its actual role is still obscure. The correct forming of 18S rRNA is a key step in the nuclear synthesis of 40S subunit. In this study, we demonstrate that rpS6 participates in the processing of 30S pre-rRNA to 18S rRNA only when its C-terminal five serines are phosphorylated, however, the process of entering the nucleus and then targeting the nucleolus does not dependent its phosphorylation. Remarkably, we also find that the aggregation of rpS6 at the nucleolus correlates to the phasing of cell cycle, beginning to concentrate in the nucleolus at later S phase and disaggregate at M phase. J. Cell. Biochem. 117: 1649-1657, 2016. © 2015 Wiley Periodicals, Inc. PMID:26639987

    16. Microbial community of salt crystals processed from Mediterranean seawater based on 16S rRNA analysis.

      PubMed

      Baati, Houda; Guermazi, Sonda; Gharsallah, Neji; Sghir, Abdelghani; Ammar, Emna

      2010-01-01

      Phylogenetic analysis of 16S rRNA was used to investigate for the first time the structure of the microbial community that inhabits salt crystals retrieved from the bottom of a solar saltern, located in the coastal area of the Mediterranean Sea (Sfax, Tunisia). This community lives in an extremely salty environment of 250-310 g/L total dissolved salt. A total of 78 bacterial 16S rRNA clone sequences making up to 21 operational taxonomic units (OTUs), determined by the DOTUR program to 97% sequence similarity, was analyzed. These OTUs were affiliated to Bacteroidetes (71.4% of OTUs), and gamma-Proteobacteria and alpha-Proteobacteria (equally represented by 14.2% of the OTUs observed). The archaeal community composition appeared more diverse with 68 clones, resulting in 44 OTUs, all affiliated with the Euryarchaeota phylum. Of the bacterial and archaeal clones showing <97% 16S rRNA sequence identity with sequences in public databases, 47.6% and 84.1% respectively were novel clones. Both rarefaction curves and diversity measurements (Simpson, Shannon-Weaver, Chao) showed a more diverse archaeal than bacterial community at the Tunisian solar saltern pond. The analysis of an increasing clone's number may reveal additional local diversity. PMID:20130693

    17. 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

    18. An end-to-end system in support of a broad scope of GOES-R sensor and data processing study

      NASA Astrophysics Data System (ADS)

      Huang, Hung-Lung

      2005-08-01

      The mission of NOAA's Geostationary Operational Environmental Satellite System (GOES) R series satellites, in the 2012 time frame, is to provide continuous, near real-time meteorological, oceanographic, solar, and space environment data that supports NOAA's strategic mission goals. It presents an exciting opportunity to explore new instruments, satellite designs, and system architectures utilizing new communication and instrument technologies in order to meet the ever-increasing demands made of Earth observation systems by national agencies and end users alike. The GOES-R sensor suite includes a 16 spectral band Advanced Baseline Imager (ABI), an approximately 1500 high spectral resolution band Hyperspectral Environmental Suite (HES), plus other sensors designed to detect lightning and to explore the ocean, solar and space environment. The Cooperative Institute for Meteorological Satellite Studies (CIMSS) as part of the Space Science and Engineering Center (SSEC) of the University of Wisconsin-Madison, the long time partner of NOAA, has developed the first operational end-to-end processing system for GOES. Based on this heritage, and with recent support from the NASA/NOAA Geosynchrous Imaging FTS (GIFTS) project, the Navy's Multiple University Research Initiative (MURI), and NOAA's GOES-R Risk Reduction program, SSEC has built a near-complete end-to-end system that is capable of simulating sensor measurements from top of atmosphere radiances, raw sensor data (level 0) through calibrated and navigated sensor physical measurements (level 1) to the processed products (level 2). In this paper, the SSEC Hyperspectral Imaging and Sounding Simulator and Processor (HISSP) will be presented in detail. HISSP is capable of demonstrating most of the processing functions such as data compression/decompression, sensor calibration, data processing, algorithm development, and product generation. In summary, HISSP is an end-to-end system designed to support both government and

    19. β -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 β -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 ,γ )⇄(γ ,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.

    20. The charge excitation in the Raman process as correlated from a classical theory for Raman optical activity: the case study of (+)-(R)-methyloxirane.

      PubMed

      Fang, Yan; Wu, Guozhen; Wang, Peijie

      2012-03-01

      We developed a classical algorithm to calculate the spectral signs in the Raman optical activity (ROA) spectrum. In this algorithm, the charge re-distributions among the bonds, which are associated to the bond polarizabilities, are included. For (+)-(R)-methyloxirane, we found that if these bond polarizabilities are attributed to the atoms and are properly scaled in order to be combined with the Mulliken charges on the atoms in the ground state, then the experimental ROA spectral signs can be well reproduced. Furthermore, in this process, we are able to determine that around 20% of the electrons in the molecule are excited in the Raman process. PMID:22226895

    1. 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 ...

    2. 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

    3. Low-Frequency Repetitive Transcranial Magnetic Stimulation (rTMS) Affects Event-Related Potential Measures of Novelty Processing in Autism

      PubMed Central

      Baruth, Joshua; Tasman, Allan; Mansoor, Mehreen; Ramaswamy, Rajesh; Sears, Lonnie; Mathai, Grace; El-Baz, Ayman; Casanova, Manuel F.

      2009-01-01

      In our previous study on individuals with autism spectrum disorder (ASD) (Sokhadze et al., Appl Psychophysiol Biofeedback 34:37–51, 2009a) we reported abnormalities in the attention-orienting frontal event-related potentials (ERP) and the sustained-attention centro-parietal ERPs in a visual oddball experiment. These results suggest that individuals with autism over-process information needed for the successful differentiation of target and novel stimuli. In the present study we examine the effects of low-frequency, repetitive Transcranial Magnetic Stimulation (rTMS) on novelty processing as well as behavior and social functioning in 13 individuals with ASD. Our hypothesis was that low-frequency rTMS application to dorsolateral prefrontal cortex (DLFPC) would result in an alteration of the cortical excitatory/inhibitory balance through the activation of inhibitory GABAergic double bouquet interneurons. We expected to find post-TMS differences in amplitude and latency of early and late ERP components. The results of our current study validate the use of low-frequency rTMS as a modulatory tool that altered the disrupted ratio of cortical excitation to inhibition in autism. After rTMS the parieto-occipital P50 amplitude decreased to novel distracters but not to targets; also the amplitude and latency to targets increased for the frontal P50 while decreasing to non-target stimuli. Low-frequency rTMS minimized early cortical responses to irrelevant stimuli and increased responses to relevant stimuli. Improved selectivity in early cortical responses lead to better stimulus differentiation at later-stage responses as was made evident by our P3b and P3a component findings. These results indicate a significant change in early, middle-latency and late ERP components at the frontal, centro-parietal, and parieto-occipital regions of interest in response to target and distracter stimuli as a result of rTMS treatment. Overall, our preliminary results show that rTMS may prove to

    4. 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

    5. 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

    6. Identification of a 67 kDa protein that binds specifically to the pre-rRNA primary processing site in a higher plant.

      PubMed

      Echeverria, M; Lahmy, S

      1995-12-25

      In radish pre-rRNA primary processing cleavage occurs at a UUUUCGCGC element (motif P) mapped in the 5'-external transcribed spacer (Delcasso-Tremousaygue et al., 1988). Significantly, motif P is part of a cluster of homologous elements including three UUUUCCGG elements (motifs A123) and a single UUUUGCCCC element (motif B). Here we used the EMSA to identify in radish extracts an RNA-binding activity, NF C, that specifically interacts with the pre-rRNA A123BP sequence. Using different RNA probes and competitors we show that NF C recognises a 38 base RNA sequence including the 3'-end of motif A3 and motifs B and P. NF C binds to poly U, but not to poly A, poly C or poly G. Therefore we used poly (U) Sepharose chromatography as a final step to obtain pure NF C fractions. These, analysed by SDS-PAGE, revealed two major polypeptides of 67 and 60 kDa. According to UV cross-linking analysis the 67 kDa polypeptide corresponds to NF C activity, while the 60 kDa species is a proteolysed form of this protein. We also showed that NF C is enriched in nuclear extracts. Based on its stringent RNA substrate specificity and its nuclear localisation we propose that NF C is involved in pre-rRNA primary processing in plants. PMID:8559652

    7. Static and fatigue testing of full-scale fuselage panels fabricated using a Therm-X(R) process

      NASA Technical Reports Server (NTRS)

      Dinicola, Albert J.; Kassapoglou, Christos; Chou, Jack C.

      1992-01-01

      Large, curved, integrally stiffened composite panels representative of an aircraft fuselage structure were fabricated using a Therm-X process, an alternative concept to conventional two-sided hard tooling and contour vacuum bagging. Panels subsequently were tested under pure shear loading in both static and fatigue regimes to assess the adequacy of the manufacturing process, the effectiveness of damage tolerant design features co-cured with the structure, and the accuracy of finite element and closed-form predictions of postbuckling capability and failure load. Test results indicated the process yielded panels of high quality and increased damage tolerance through suppression of common failure modes such as skin-stiffener separation and frame-stiffener corner failure. Finite element analyses generally produced good predictions of postbuckled shape, and a global-local modelling technique yielded failure load predictions that were within 7% of the experimental mean.

    8. 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.

    9. 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...

    10. 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...

    11. The Relationship of Teacher Perceptions to Classroom Processes and Student Outcomes. R&D Rep. No. 6109.

      ERIC Educational Resources Information Center

      Clements, Barbara S.

      Considerable research has been done relating measures of teacher personality or attitudes to classroom behaviors, pupil achievement, and pupil attitudes. The major purpose of these studies has been to identify patterns of classroom behaviors, attitudes, concerns, and conceptual processes which characterize teachers. Fifty-one junior high teachers…

    12. NATO/CCMS PILOT STUDY CLEAN PRODUCTS AND PROCESSES (PHASE 1) 1998 ANNUAL REPORT (EPA/600/R-98/065)

      EPA Science Inventory

      This annual report presents the proceedings of the first annual NATO/CCMS pilot study meeting in Cincinnati in March 1998. Guest speakers focused on efforts in the research arena of clean products, clean processes, life cycle analysis, ecolabeling, and pollution prevention tools.

    13. Report on the Analysis of Some Process-Oriented Curricula. An Annotated Listing. Program Report R101.

      ERIC Educational Resources Information Center

      Bernstein, Susan; And Others

      This report contains 20 summary-descriptions of curriculum programs and materials selected by the Institute for possible inclusion in its synthesis and validation of a K-6 process-promoting curriculum. Each description includes information on the developer and publisher plus a list of references (mostly published descriptions and critiques).…

    14. HST/STIS abundances in the uranium rich metal poor star CS 31082-001: Constraints on the r-Process

      NASA Astrophysics Data System (ADS)

      Siqueira-Mello, C.; Spite, M.; Barbuy, B.; Spite, F.; Caffau, E.; Hill, V.; Wanajo, S.; Primas, F.; Plez, B.; Cayrel, R.; Andersen, J.; Nordström, B.; Sneden, C.; Beers, T. C.; Bonifacio, P.; François, P.; Molaro, P.

      2016-01-01

      As a brief revision, the origin of heavy elements and the role of abundances in extremely metal-poor (EMP) stars are presented. Heavy element abundances in the EMP uranium-rich star CS 31082-001 based mainly on near-UV spectra from STIS/HST are presented. These results should be useful for a better characterisation of the neutron exposure(s) that produced the r-process elements in this star, as well as a guide for improving nuclear data and astrophysical site modelling, given that the new element abundances not available in previous works (Ge, Mo, Lu, Ta, W, Re, Pt, Au, and Bi) make CS 31082-001 the most completely well studied r-II object, with a total of 37 detections of n-capture elements.

    15. Viable RNaseH1 knockout mice show RNaseH1 is essential for R loop processing, mitochondrial and liver function

      PubMed Central

      Lima, Walt F.; Murray, Heather M.; Damle, Sagar S.; Hart, Christopher E.; Hung, Gene; De Hoyos, Cheryl Li; Liang, Xue-Hai; Crooke, Stanley T.

      2016-01-01

      Viable constitutive and tamoxifen inducible liver-specific RNase H1 knockout mice that expressed no RNase H1 activity in hepatocytes showed increased R-loop levels and reduced mitochondrial encoded DNA and mRNA levels, suggesting impaired mitochondrial R-loop processing, transcription and mitochondrial DNA replication. These changes resulted in mitochondrial dysfunction with marked changes in mitochondrial fusion, fission, morphology and transcriptional changes reflective of mitochondrial damage and stress. Liver degeneration ensued, as indicated by apoptosis, fibrosis and increased transaminase levels. Antisense oligonucleotides (ASOs) designed to serve as substrates for RNase H1 were inactive in the hepatocytes from the RNase H1 knockout mice and in vivo, demonstrating that RNase H1 is necessary for the activity of DNA-like ASOs. During liver regeneration, a clone of hepatocytes that expressed RNase H1 developed and partially restored mitochondrial and liver function. PMID:27131367

    16. Viable RNaseH1 knockout mice show RNaseH1 is essential for R loop processing, mitochondrial and liver function.

      PubMed

      Lima, Walt F; Murray, Heather M; Damle, Sagar S; Hart, Christopher E; Hung, Gene; De Hoyos, Cheryl Li; Liang, Xue-Hai; Crooke, Stanley T

      2016-06-20

      Viable constitutive and tamoxifen inducible liver-specific RNase H1 knockout mice that expressed no RNase H1 activity in hepatocytes showed increased R-loop levels and reduced mitochondrial encoded DNA and mRNA levels, suggesting impaired mitochondrial R-loop processing, transcription and mitochondrial DNA replication. These changes resulted in mitochondrial dysfunction with marked changes in mitochondrial fusion, fission, morphology and transcriptional changes reflective of mitochondrial damage and stress. Liver degeneration ensued, as indicated by apoptosis, fibrosis and increased transaminase levels. Antisense oligonucleotides (ASOs) designed to serve as substrates for RNase H1 were inactive in the hepatocytes from the RNase H1 knockout mice and in vivo, demonstrating that RNase H1 is necessary for the activity of DNA-like ASOs. During liver regeneration, a clone of hepatocytes that expressed RNase H1 developed and partially restored mitochondrial and liver function. PMID:27131367

    17. Magnetocaloric effect of RM2 (R = rare earth, M = Ni, Al) intermetallic compounds made by centrifugal atomization process for magnetic refrigerator

      NASA Astrophysics Data System (ADS)

      Matsumoto, K.; Asamato, K.; Nishimura, Y.; Zhu, Y.; Abe, S.; Numazawa, T.

      2012-12-01

      RM2 (R = rare earth, M = Al, Ni and Co) compounds have large entropy change and magnetic transition temperatures can be controlled by change of R and/or M so that are suitable to a magnetic refrigerator for hydrogen liquefaction under development. In order to improve refrigerator performance, spherical powdered HoAl2, DyAl2, and GdNi2 compounds with submillimeter diameter were synthesized by centrifugal atomization process. By measuring the magnetization and heat capacity, we obtained entropy change by magnetic fields and entropy as functions of temperature and magnetic field, which are essential for analysing the magnetic refrigeration cycle. All samples showed sharp magnetic transitions and had good potentials for use in magnetic refrigeration.

    18. 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.

    19. {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.

    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. 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

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

    3. 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.

    4. Chemogenomic Study of Carboplatin in Saccharomyces cerevisiae: Inhibition of the NEDDylation Process Overcomes Cellular Resistance Mediated by HuR and Cullin Proteins.

      PubMed

      de Sousa, Graziele Fonseca; Lima, Maira de Assis; 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

    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. 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

    7. Experimental study of the B11,12(n,γ) reactions and their influence on r-process nucleosynthesis of light elements

      NASA Astrophysics Data System (ADS)

      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.

      2010-01-01

      We have studied the neutron-transfer reactions B11,12(d,p)B12,13 in inverse kinematics to obtain information about the neutron-capture reactions B11,12(n,γ). 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 B12,13 were deduced and the branching ratio of the neutron-unbound state at EX=3.389 MeV in B12 was obtained to provide the ratio of partial widths, Γn/Γγ. The reaction rates for B11,12(n,γ) 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.

    8. 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.

    9. 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

    10. EVALUATING REGIONAL PREDICTIVE CAPACITY OF A PROCESS-BASED MERCURY EXPOSURE MODEL, REGIONAL-MERCURY CYCLING MODEL (R-MCM), APPLIED TO 91 VERMONT AND NEW HAMPSHIRE LAKES AND PONDS, USA

      EPA Science Inventory

      Regulatory agencies must develop fish consumption advisories for many lakes and rivers with limited resources. Process-based mathematical models are potentially valuable tools for developing regional fish advisories. The Regional Mercury Cycling model (R-MCM) was specifically d...

    11. 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

      2015-01-01

      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

    12. Quantification of Listeria monocytogenes in minimally processed leafy vegetables using a combined method based on enrichment and 16S rRNA real-time PCR.

      PubMed

      Aparecida de Oliveira, Maria; Abeid Ribeiro, Eliana Guimarães; Morato Bergamini, Alzira Maria; Pereira De Martinis, Elaine Cristina

      2010-02-01

      Modern lifestyle markedly changed eating habits worldwide, with an increasing demand for ready-to-eat foods, such as minimally processed fruits and leafy greens. Packaging and storage conditions of those products may favor the growth of psychrotrophic bacteria, including the pathogen Listeria monocytogenes. In this work, minimally processed leafy vegetables samples (n = 162) from retail market from Ribeirão Preto, São Paulo, Brazil, were tested for the presence or absence of Listeria spp. by the immunoassay Listeria Rapid Test, Oxoid. Two L. monocytogenes positive and six artificially contaminated samples of minimally processed leafy vegetables were evaluated by the Most Probable Number (MPN) with detection by classical culture method and also culture method combined with real-time PCR (RTi-PCR) for 16S rRNA genes of L. monocytogenes. Positive MPN enrichment tubes were analyzed by RTi-PCR with primers specific for L. monocytogenes using the commercial preparation ABSOLUTE QPCR SYBR Green Mix (ABgene, UK). Real-time PCR assay presented good exclusivity and inclusivity results and no statistical significant difference was found in comparison with the conventional culture method (p < 0.05). Moreover, RTi-PCR was fast and easy to perform, with MPN results obtained in ca. 48 h for RTi-PCR in comparison to 7 days for conventional method. PMID:19913686

    13. SWATH2stats: An R/Bioconductor Package to Process and Convert Quantitative SWATH-MS Proteomics Data for Downstream Analysis Tools

      PubMed Central

      Blattmann, Peter; Heusel, Moritz; Aebersold, Ruedi

      2016-01-01

      SWATH-MS is an acquisition and analysis technique of targeted proteomics that enables measuring several thousand proteins with high reproducibility and accuracy across many samples. OpenSWATH is popular open-source software for peptide identification and quantification from SWATH-MS data. For downstream statistical and quantitative analysis there exist different tools such as MSstats, mapDIA and aLFQ. However, the transfer of data from OpenSWATH to the downstream statistical tools is currently technically challenging. Here we introduce the R/Bioconductor package SWATH2stats, which allows convenient processing of the data into a format directly readable by the downstream analysis tools. In addition, SWATH2stats allows annotation, analyzing the variation and the reproducibility of the measurements, FDR estimation, and advanced filtering before submitting the processed data to downstream tools. These functionalities are important to quickly analyze the quality of the SWATH-MS data. Hence, SWATH2stats is a new open-source tool that summarizes several practical functionalities for analyzing, processing, and converting SWATH-MS data and thus facilitates the efficient analysis of large-scale SWATH/DIA datasets. PMID:27054327

    14. Upbend and M1 scissors mode in neutron-rich nuclei - consequences for r-process $$(n,\\gamma )$$ reaction rates

      DOE PAGESBeta

      Larsen, A. C.; Goriely, S.; Bernstein, L. A.; Bleuel, D. L.; Bracco, A.; Brown, B. A.; Camera, F.; Eriksen, T. K.; Frauendorf, S.; Giacoppo, F.; et al

      2015-01-01

      An enhanced probability for low-energy γ-emission (upbend, Eγ < 3 MeV) at high excitation energies has been observed for several light and medium-mass nuclei close to the valley of stability. Also the M1 scissors mode seen in deformed nuclei increases the γ-decay probability for low-energy γ-rays (Eγ ≈ 2–3 MeV). These phenomena, if present in neutron-rich nuclei, have the potential to increase radiative neutron-capture rates relevant for the r-process. Furthermore, the experimental and theoretical status of the upbend is discussed, and preliminary calculations of (n,γ) reaction rates for neutron-rich, mid-mass nuclei including the scissors mode are shown.

    15. Upbend and M1 scissors mode in neutron-rich nuclei - consequences for r-process $(n,\\gamma )$ reaction rates

      SciTech Connect

      Larsen, A. C.; Goriely, S.; Bernstein, L. A.; Bleuel, D. L.; Bracco, A.; Brown, B. A.; Camera, F.; Eriksen, T. K.; Frauendorf, S.; Giacoppo, F.; Guttormsen, M.; Gorgen, A.; Harissopulos, S.; Leoni, S.; Liddick, S. N.; Naqvi, F.; Nyhus, H. T.; Rose, S. J.; Renstrom, T.; Schwengner, R.; Siem, S.; Spyrou, A.; Tveten, G. M.; Voinov, A. V.; Wiedeking, M.

      2015-01-01

      An enhanced probability for low-energy γ-emission (upbend, Eγ < 3 MeV) at high excitation energies has been observed for several light and medium-mass nuclei close to the valley of stability. Also the M1 scissors mode seen in deformed nuclei increases the γ-decay probability for low-energy γ-rays (Eγ ≈ 2–3 MeV). These phenomena, if present in neutron-rich nuclei, have the potential to increase radiative neutron-capture rates relevant for the r-process. Furthermore, the experimental and theoretical status of the upbend is discussed, and preliminary calculations of (n,γ) reaction rates for neutron-rich, mid-mass nuclei including the scissors mode are shown.

    16. Diverse nucleosynthetic components in barium isotopes of carbonaceous chondrites: Incomplete mixing of s- and r-process isotopes and extinct 135Cs in the early solar system

      NASA Astrophysics Data System (ADS)

      Hidaka, Hiroshi; Yoneda, Shigekazu

      2011-07-01

      Barium isotopic compositions of chemical leachates from six carbonaceous chondrites, Orgueil (CI), Mighei (CM2), Murray (CM2), Efremovka (CV3), Kainsaz (CO3), and Karoonda (CK4), were determined using thermal ionization mass spectrometry in order to assess the chemical evolution in the early solar system. The Ba isotopic data from most of the leachates show variable 135Ba excesses correlated with 137Ba excesses, suggesting the presence and heterogeneity of additional nucleosynthetic components for s- and r-processes in the solar system. The isotopic deviations observed in this study were generally small (-1 < ɛ < +1) except in the case of the acid residues of CI and CM meteorites. Large deviations of 135Ba (ɛ = -13.5 to -5.0) and 137Ba (ɛ = -6.2˜-1.2) observed in the acid residues from one CI and two CM meteorites show significant evidence for the enrichment of s-process isotopes derived from presolar grains. Two models were proposed to estimate the 135Cs isotopic abundances by subtraction of the s- and r-isotopic components from the total Ba isotopic abundances in the three CM meteorites, Mighei, Murchison (measured in a previous study), and Murray. The data points show individual linear trends between 135Cs/ 136Ba ratios and 135Ba isotopic deviations for the three samples. Considering the different trends observed in the three CM meteorites, the Ba isotopic composition of the CM meteorite parent body was heterogeneous at its formation. Chronological information is unclear in the data for Murchison and Murray because of large analytical uncertainties imposed by error propagation. Only the Mighei meteorite data indicate the possible existence of presently extinct 135Cs ( 135Cs/ 133Cs = (2.7 ± 1.6) × 10 -4) in the early solar system. Another explanation of the data for the three CM meteorite is mixing of at least three components with different Ba isotopic compositions, although this is model-dependent.

    17. 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.

    18. GOES-R Space Environment In-Situ Suite: instruments overview, calibration results, and data processing algorithms, and expected on-orbit performance

      NASA Astrophysics Data System (ADS)

      Galica, G. E.; Dichter, B. K.; Tsui, S.; Golightly, M. J.; Lopate, C.; Connell, J. J.

      2016-05-01

      The space weather instruments (Space Environment In-Situ Suite - SEISS) on the soon to be launched, NOAA GOES-R series spacecraft offer significant space weather measurement performance advances over the previous GOES N-P series instruments. The specifications require that the instruments ensure proper operation under the most stressful high flux conditions corresponding to the largest solar particle event expected during the program, while maintaining high sensitivity at low flux levels. Since the performance of remote sensing instruments is sensitive to local space weather conditions, the SEISS data will be of be of use to a broad community of users. The SEISS suite comprises five individual sensors and a data processing unit: Magnetospheric Particle Sensor-Low (0.03-30 keV electrons and ions), Magnetospheric Particle Sensor-High (0.05-4 MeV electrons, 0.08-12 MeV protons), two Solar And Galactic Proton Sensors (1 to >500 MeV protons), and the Energetic Heavy ion Sensor (10-200 MeV for H, H to Fe with single element resolution). We present comparisons between the enhanced GOES-R instruments and the current GOES space weather measurement capabilities. We provide an overview of the sensor configurations and performance. Results of extensive sensor modeling with GEANT, FLUKA and SIMION are compared with calibration data measured over nearly the entire energy range of the instruments. Combination of the calibration results and model are used to calculate the geometric factors of the various energy channels. The calibrated geometric factors and typical and extreme space weather environments are used to calculate the expected on-orbit performance.

    19. Oxygenated fraction and mass of organic aerosol from direct emission and atmospheric processing measured on the R/V Ronald Brown during TEXAQS/GoMACCS 2006

      NASA Astrophysics Data System (ADS)

      Russell, L. M.; Takahama, S.; Liu, S.; Hawkins, L. N.; Covert, D. S.; Quinn, P. K.; Bates, T. S.

      2009-04-01

      Submicron particles collected on Teflon filters aboard the R/V Ronald Brown during the Texas Air Quality Study and Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS/GoMACCS) 2006 in and around the port of Houston, Texas, were measured by Fourier transform infrared (FTIR) and X-ray fluorescence for organic functional groups and elemental composition. Organic mass (OM) concentrations (1-25 μg m-3) for ambient particle samples measured by FTIR showed good agreement with measurements made with an aerosol mass spectrometer. The fractions of organic mass identified as alkane and carboxylic acid groups were 47% and 32%, respectively. Three different types of air masses were identified on the basis of the air mass origin and the radon concentration, with significantly higher carboxylic acid group mass fractions in air masses from the north (35%) than the south (29%) or Gulf of Mexico (26%). Positive matrix factorization analysis attributed carboxylic acid fractions of 30-35% to factors with mild or strong correlations (r > 0.5) to elemental signatures of oil combustion and 9-24% to wood smoke, indicating that part of the carboxylic acid fraction of OM was formed by the same sources that controlled the metal emissions, namely the oil and wood combustion activities. The implication is that a substantial part of the measured carboxylic acid contribution was formed independently of traditionally "secondary" processes, which would be affected by atmospheric (both photochemical and meteorological) conditions and other emission sources. The carboxylic acid group fractions in the Gulf of Mexico and south air masses (GAM and SAM, respectively) were largely oil combustion emissions from ships as well as background marine sources, with only limited recent land influences (based on radon concentrations). Alcohol groups accounted for 14% of OM (mostly associated with oil combustion emissions and background sources), and amine groups accounted for 4% of OM in all air

    20. Yeast polypeptide exit tunnel ribosomal proteins L17, L35 and L37 are necessary to recruit late-assembling factors required for 27SB pre-rRNA processing

      PubMed Central

      Gamalinda, Michael; Jakovljevic, Jelena; Babiano, Reyes; Talkish, Jason; de la Cruz, Jesús; Woolford, John L.

      2013-01-01

      Ribosome synthesis involves the coordinated folding and processing of pre-rRNAs with assembly of ribosomal proteins. In eukaryotes, these events are facilitated by trans-acting factors that propel ribosome maturation from the nucleolus to the cytoplasm. However, there is a gap in understanding how ribosomal proteins configure pre-ribosomes in vivo to enable processing to occur. Here, we have examined the role of adjacent yeast r-proteins L17, L35 and L37 in folding and processing of pre-rRNAs, and binding of other proteins within assembling ribosomes. These three essential ribosomal proteins, which surround the polypeptide exit tunnel, are required for 60S subunit formation as a consequence of their role in removal of the ITS2 spacer from 27SB pre-rRNA. L17-, L35- and L37-depleted cells exhibit turnover of aberrant pre-60S assembly intermediates. Although the structure of ITS2 does not appear to be grossly affected in their absence, these three ribosomal proteins are necessary for efficient recruitment of factors required for 27SB pre-rRNA processing, namely, Nsa2 and Nog2, which associate with pre-60S ribosomal particles containing 27SB pre-rRNAs. Altogether, these data support that L17, L35 and L37 are specifically required for a recruiting step immediately preceding removal of ITS2. PMID:23268442

    1. 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.

    2. 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 β 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 μm, 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.

    3. Process

      SciTech Connect

      Geenen, P.V.; Bennis, J.

      1989-04-04

      A process is described for minimizing the cracking tendency and uncontrolled dimensional change, and improving the strength of a rammed plastic refractory reactor liner comprising phosphate-bonded silicon carbide or phosphate-bonded alumina. It consists of heating the reactor liner placed or mounted in a reactor, prior to its first use, from ambient temperature up to a temperature of from about 490/sup 0/C to about 510/sup 0/C, the heating being carried out by heating the liner at a rate to produce a temperature increase of the liner not greater than about 6/sup 0/C per hour.

    4. 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

    5. Dyskerin is required for tumor cell growth through mechanisms that are independent of its role in telomerase and only partially related to its function in precursor rRNA processing

      PubMed Central

      Alawi, Faizan; Lin, Ping

      2010-01-01

      Dyskerin is an essential nucleolar protein required for the biogenesis of ribonucleoproteins that incorporate H/ACA RNAs. Through binding to specific H/ACA RNAs, dyskerin exerts most of its influence in the cell. To that end, dyskerin is a core component of the telomerase complex and is required for normal telomere maintenance. Dyskerin is also required for post-transcriptional processing of precursor rRNA. Germline dyskerin mutations increase cancer susceptibility. Conversely, wild-type dyskerin is usually overexpressed and not mutated in sporadic cancers. However, the contributions of dyskerin to sporadic tumorigenesis are unknown. Described herein, we demonstrate that acute loss of dyskerin function by RNA interference significantly reduced steady-state levels of H/ACA RNAs, disrupted the morphology and inhibited anchorage-independent growth of telomerase-positive and telomerase-negative human cell lines. Unexpectedly, dyskerin depletion only transiently delayed rRNA maturation but with no appreciable effect on the levels of total 18S or 28S rRNA. Instead, while rRNA processing defects typically trigger p53-dependent G1 arrest, dyskerin-depleted cells accumulated in G2/M by a p53-independent mechanism, and this was associated with an accumulation of aberrant mitotic figures that were characterized by multi-polar spindles. Telomerase activity and the rate of rRNA processing are typically increased during neoplasia. However, our cumulative findings indicate that dyskerin contributes to tumor cell growth through mechanisms which do not require the presence of cellular telomerase activity, and which may be only partially dependent upon the protein’s role in rRNA processing. These data also reinforce the notion that loss and gain of dyskerin function may play important roles in tumorigenesis. PMID:21480387

    6. 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.

    7. 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.

    8. SOT1, a pentatricopeptide repeat protein with a small MutS-related domain, is required for correct processing of plastid 23S-4.5S rRNA precursors in Arabidopsis thaliana.

      PubMed

      Wu, Wenjuan; Liu, Sheng; Ruwe, Hannes; Zhang, Delin; Melonek, Joanna; Zhu, Yajuan; Hu, Xupeng; Gusewski, Sandra; Yin, Ping; Small, Ian D; Howell, Katharine A; Huang, Jirong

      2016-03-01

      Ribosomal RNA processing is essential for plastid ribosome biogenesis, but is still poorly understood in higher plants. Here, we show that SUPPRESSOR OF THYLAKOID FORMATION1 (SOT1), a plastid-localized pentatricopeptide repeat (PPR) protein with a small MutS-related domain, is required for maturation of the 23S-4.5S rRNA dicistron. Loss of SOT1 function leads to slower chloroplast development, suppression of leaf variegation, and abnormal 23S and 4.5S processing. Predictions based on the PPR motif sequences identified the 5' end of the 23S-4.5S rRNA dicistronic precursor as a putative SOT1 binding site. This was confirmed by electrophoretic mobility shift assay, and by loss of the abundant small RNA 'footprint' associated with this site in sot1 mutants. We found that more than half of the 23S-4.5S rRNA dicistrons in sot1 mutants contain eroded and/or unprocessed 5' and 3' ends, and that the endonucleolytic cleavage product normally released from the 5' end of the precursor is absent in a sot1 null mutant. We postulate that SOT1 binding protects the 5' extremity of the 23S-4.5S rRNA dicistron from exonucleolytic attack, and favours formation of the RNA structure that allows endonucleolytic processing of its 5' and 3' ends. PMID:26800847

    9. rAAV-mediated overexpression of sox9, TGF-β and IGF-I in minipig bone marrow aspirates to enhance the chondrogenic processes for cartilage repair.

      PubMed

      Frisch, J; Rey-Rico, A; Venkatesan, J K; Schmitt, G; Madry, H; Cucchiarini, M

      2016-03-01

      Administration of therapeutic gene sequences coding for chondrogenic and chondroreparative factors in bone marrow aspirates using the clinically adapted recombinant adeno-associated virus (rAAV) vector may provide convenient, single-step approaches to improve cartilage repair. Here, we tested the ability of distinct rAAV constructs coding for the potent SOX9, transforming growth factor beta (TGF-β) and insulin-like growth factor I (IGF-I) candidate factors to modify marrow aspirates from minipigs to offer a preclinical large animal model system adapted for a translational evaluation of cartilage repair upon transplantation in sites of injury. Our results demonstrate that high, prolonged rAAV gene transfer efficiencies were achieved in the aspirates (up to 100% for at least 21 days) allowing to produce elevated amounts of the transcription factor SOX9 that led to increased levels of matrix synthesis and chondrogenic differentiation and of the growth factors TGF-β and IGF-I that both increased cell proliferation, matrix synthesis and chondrogenic differentiation (although to a lower level than SOX9) compared with control (lacZ) condition. Remarkably, application of the candidate SOX9 vector also led to reduced levels of hypertrophic differentiation in the aspirates, possibly by modulating the β-catenin, Indian hedgehog and PTHrP pathways. The present findings show the benefits of modifying minipig marrow concentrates via rAAV gene transfer as a future means to develop practical strategies to promote cartilage repair in a large animal model. PMID:26583804

    10. 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.

    11. C-C and C-Heteroatom Bond Dissociation Energies in CH 3 R'C(OH) 2 : Energetics for Photocatalytic Processes of Organic Diolates on TiO 2 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.

    12. Early Stages of Melody Processing: Stimulus-Sequence and Task-Dependent Neuronal Activity in Monkey Auditory Cortical Fields A1 and R

      PubMed Central

      Yin, Pingbo; Mishkin, Mortimer; Sutter, Mitchell; Fritz, Jonathan B.

      2008-01-01

      To explore the effects of acoustic and behavioral context on neuronal responses in the core of auditory cortex (fields A1 and R), two monkeys were trained on a go/no-go discrimination task in which they learned to respond selectively to a four-note target (S+) melody and withhold response to a variety of other nontarget (S−) sounds. We analyzed evoked activity from 683 units in A1/R of the trained monkeys during task performance and from 125 units in A1/R of two naive monkeys. We characterized two broad classes of neural activity that were modulated by task performance. Class I consisted of tone-sequence–sensitive enhancement and suppression responses. Enhanced or suppressed responses to specific tonal components of the S+ melody were frequently observed in trained monkeys, but enhanced responses were rarely seen in naive monkeys. Both facilitatory and suppressive responses in the trained monkeys showed a temporal pattern different from that observed in naive monkeys. Class II consisted of nonacoustic activity, characterized by a task-related component that correlated with bar release, the behavioral response leading to reward. We observed a significantly higher percentage of both Class I and Class II neurons in field R than in A1. Class I responses may help encode a long-term representation of the behaviorally salient target melody. Class II activity may reflect a variety of nonacoustic influences, such as attention, reward expectancy, somatosensory inputs, and/or motor set and may help link auditory perception and behavioral response. Both types of neuronal activity are likely to contribute to the performance of the auditory task. PMID:18842950

    13. Early stages of melody processing: stimulus-sequence and task-dependent neuronal activity in monkey auditory cortical fields A1 and R.

      PubMed

      Yin, Pingbo; Mishkin, Mortimer; Sutter, Mitchell; Fritz, Jonathan B

      2008-12-01

      To explore the effects of acoustic and behavioral context on neuronal responses in the core of auditory cortex (fields A1 and R), two monkeys were trained on a go/no-go discrimination task in which they learned to respond selectively to a four-note target (S+) melody and withhold response to a variety of other nontarget (S-) sounds. We analyzed evoked activity from 683 units in A1/R of the trained monkeys during task performance and from 125 units in A1/R of two naive monkeys. We characterized two broad classes of neural activity that were modulated by task performance. Class I consisted of tone-sequence-sensitive enhancement and suppression responses. Enhanced or suppressed responses to specific tonal components of the S+ melody were frequently observed in trained monkeys, but enhanced responses were rarely seen in naive monkeys. Both facilitatory and suppressive responses in the trained monkeys showed a temporal pattern different from that observed in naive monkeys. Class II consisted of nonacoustic activity, characterized by a task-related component that correlated with bar release, the behavioral response leading to reward. We observed a significantly higher percentage of both Class I and Class II neurons in field R than in A1. Class I responses may help encode a long-term representation of the behaviorally salient target melody. Class II activity may reflect a variety of nonacoustic influences, such as attention, reward expectancy, somatosensory inputs, and/or motor set and may help link auditory perception and behavioral response. Both types of neuronal activity are likely to contribute to the performance of the auditory task. PMID:18842950

    14. Investigation of a miRNA-Induced Gene Silencing Technique in Petunia Reveals Alterations in miR173 Precursor Processing and the Accumulation of Secondary siRNAs from Endogenous Genes

      PubMed Central

      Han, Yao; Zhang, Bin; Qin, Xiaoting; Li, Mingyang; Guo, Yulong

      2015-01-01

      MIGS (miRNA-induced gene silencing) is a straightforward and efficient gene silencing technique in Arabidopsis. It works by exploiting miR173 to trigger the production of phasiRNAs (phased small interfering RNAs). MIGS can be used in plant species other than Arabidopsis by co-expression of miR173 and target gene fragments fused to an upstream miR173 target site. However, the efficiency and technical mechanisms have not been thoroughly investigated in other plants. In this work, two vectors, pMIGS-chs and pMIGS-pds, were constructed and transformed into petunia plants. The transgenic plants showed CHS (chalcone synthase) and PDS (phytoene desaturase) gene-silencing phenotypes respectively, indicating that MIGS functions in petunia. MIGS-chs plants were used to investigate the mechanisms of this technique in petunia. Results of 5′- RACE showed that the miR173 target site was cleaved at the expected position and that endogenous CHS genes were cut at multiple positions. Small RNA deep sequencing analysis showed that the processing of Arabidopsis miR173 precursors in MIGS-chs transgenic petunia plants did not occur in exactly the same way as in Arabidopsis, suggesting differences in the machinery of miRNA processing between plant species. Small RNAs in-phase with the miR173 cleavage register were produced immediately downstream from the cleavage site and out-of-phase small RNAs were accumulated at relatively high levels from processing cycle 5 onwards. Secondary siRNAs were generated from multiple sites of endogenous CHS-A and CHS-J genes, indicating that miR173 cleavage induced siRNAs have the same ability to initiate siRNA transitivity as the siRNAs functioning in co-suppression and hpRNA silencing. On account of the simplicity of vector construction and the transitive amplification of signals from endogenous transcripts, MIGS is a good alternative gene silencing method for plants, especially for silencing a cluster of homologous genes with redundant functions. PMID

    15. 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...

    16. β-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 β-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,γ)⇄(γ,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

    17. 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 SUMMARY

      SciTech Connect

      Lawler, J. E.; Den Hartog, E. A.; Sneden, C.; Cowan, J. J.; Ivans, I. I. E-mail: eadenhar@wisc.edu E-mail: cowan@nhn.ou.edu

      2009-05-15

      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{sup 0}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-only model predictions for solar system material. This consistent match with small scatter over a wide range of stellar metallicities lends support to these predictions of elemental fractions. A companion paper includes an interpretation of these new precision abundance results for Ce as well as new abundance results and interpretation for Pr, Dy, and Tm.

    18. Providing for the consideration of the bill (H.R. 3372) to provide a process for ensuring the United States does not default on its obligations.

      THOMAS, 113th Congress

      Rep. Honda, Michael M. [D-CA-17

      2014-01-14

      02/04/2014 Motion to Discharge Committee filed by Mr. Honda. Petition No: 113-6. (Discharge petition text with signatures.) (All Actions) Notes: On 2/4/2014, a motion was filed to discharge the Committee on Rules from the consideration of H.Res.459 a resolution providing for the consideration of H.R. 3372. A discharge petition requires 218 signatures for further action. (Discharge Petition No. 113-6: text with signatures.) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

    19. Processing of a composite large subunit rRNA. Studies with chlamydomonas mutants deficient in maturation of the 23s-like rrna.

      PubMed Central

      Holloway, S P; Herrin, D L

      1998-01-01

      (Cr.LSU). Little is known of the cis and trans requirements or of the processing pathway for this essential RNA. Previous work showed that the ribosome-deficient ac20 mutant overaccumulates an unspliced large subunit (LSU) RNA, suggesting that it might be a splicing mutant. To elucidate the molecular basis of the ac20 phenotype, a detailed analysis of the rrn transcripts in ac20 and wild-type cells was performed. The results indicate that processing of the ITSs, particularly ITS-1, is inefficient in ac20 and that ITS processing occurs after splicing. Deletion of the Cr.LSU intron from ac20 also did not alleviate the mutant phenotype. Thus, the primary defect in ac20 is not splicing but most likely is associated with ITS processing. A splicing deficiency was studied by transforming wild-type cells with rrnL genes containing point mutations in the intron core. Heteroplasmic transformants were obtained in most cases, except for P4 helix mutants; these strains grew slowly, were light sensitive, and had an RNA profile indicative of inefficient splicing. Transcript analysis in the P4 mutants also indicated that ITS processing can occur on an unspliced precursor, although with reduced efficiency. These latter results indicate that although there is not an absolutely required order for LSU processing, there does seem to be a preferred order that results in efficient processing in vivo. PMID:9668137

    20. The yeast NOP4 gene product is an essential nucleolar protein required for pre-rRNA processing and accumulation of 60S ribosomal subunits.

      PubMed Central

      Sun, C; Woolford, J L

      1994-01-01

      The Saccharomyces cerevisiae NOP4 gene was isolated by screening a lambda gt11 yeast genomic DNA library with a monoclonal antibody against a yeast nucleolar protein. NOP4 encodes a 78 kDa protein that contains two prototypical RNA recognition motifs (RRMs) flanking an imperfect RRM lacking characteristic RNP1 and RNP2 motifs. In addition, there is a fourth incomplete RRM. NOP4 is a single copy essential gene present on chromosome XVI, between RAD1 and PEP4. To examine the function of Nop4p, we constructed a conditional null allele of NOP4 by placing this gene under the control of the glucose-repressible GAL1 promoter. When cells are shifted from galactose-containing medium to glucose-containing medium, NOP4 transcription is terminated, Nop4 protein is depleted and cell growth is impaired. Nop4 protein depletion results in diminished accumulation of 60S ribosomal subunits, assignable to a defect in ribosome biogenesis arising from a lack of production of mature 25S rRNA from 27S precursor rRNA. Images PMID:8039505

    1. Two ribosomal DNA-binding factors interact with a cluster of motifs on the 5' external transcribed spacer, upstream from the primary pre-rRNA processing site in a higher plant.

      PubMed

      Caparros-Ruiz, D; Lahmy, S; Piersanti, S; Echeverría, M

      1997-08-01

      In radish the primary processing site in pre-rRNA has been mapped to a TTTTCGCGC sequence (motif P) in the 5' external transcribed spacer (5' ETS) of the ribosomal DNA (rDNA) [Delcasso-Tremousaygue, D., Grellet, F., Panabières, F., Ananiev, E. & Delseny, M. (1988) Eur. J. Biochem. 172, 767-776]. The processing site is just downstream of four similar motifs named A1, A2, A3 and B. The five motifs constitute cluster A123BP. We have described previously that in radish extracts a nuclear protein, nuclear factor B (NF B) specifically binds to motif B [Echeverría, M., Penon, P. & Delseny, M. (1994) Mol. Gen. Genet. 243, 442-452]. Here, by means of electrophoretic-mobility-shift assays, we describe an rDNA-binding activity, nuclear factor D (NF D), that interacts with the A123BP cluster. Using various rDNA probes and competitors we show that NF D binds specifically to the A123 clustered motifs but not to similar B or P motifs. We used sequence-specific DNA-affinity chromatography to separate NF D from NF B. DNase I footprinting was used to map the binding site of NF D on the A123BP cluster and we compared it with that of NF B on the same probe. The footprint of NF D extends from the A1 motif to the 5' end of the NF B-binding site and includes motifs A2 and A3 on each strand. The footprinting of NF B is restricted to motif B and adjacent nucleotides. Thus the NF D-binding and NF B-binding sites are distinct but overlap. These two factors bind with a high specificity to the A123BP cluster in the radish 5' ETS. The possibility that these factors regulate rDNA transcription elongation at the level of the primary pre-rRNA processing site in crucifers is discussed. PMID:9288923

    2. 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…

    3. 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…

    4. 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...

    5. EVALUATING THE REGIONAL PREDICTIVE CAPACITY OF A PROCESS-BASED MERCURY EXPOSURE MODEL (R-MCM) FOR LAKES ACROSS VERMONT AND NEW HAMPSHIRE, USA

      EPA Science Inventory

      Regulatory agencies are confronted with a daunting task of developing fish consumption advisories for a large number of lakes and rivers with little resources. A feasible mechanism to develop region-wide fish advisories is by using a process-based mathematical model. One model of...

    6. 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…

    7. 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.

    8. Multi-tiered system of support incorporating the R.E.N.E.W. process and its relationship to perception of school safety and office discipline referrals

      NASA Astrophysics Data System (ADS)

      Flood, Molly M.

      This study examined the relationship between the fidelity of multi-tier school-wide positive behavior interventions and supports (SWPBIS) and staff perception of school safety and office discipline referrals. This research provided a case study on multi-tier supports and interventions, and the RENEW person-centered planning process in an alternative special education center following the implementation of a multi-tier SWPBIS model. Pennsylvania is one of several states looking to adopt an effective Tier III behavioral tool. The research described the results of an analysis of implementation fidelity on a multi-tiered school-wide positive behavior support model developed at a special education center operated by a public school system entity. This research explored the fidelity of SWPBIS implementation; analyzed the relationship of SWPBIS to school climate as measured by staff perceptions and reduction of office discipline referrals (ODR); explored tier III supports incorporating a process Rehabilitation and Empowerment, Natural Supports, Education and Work (RENEW); and investigated the potential sustainability of the RENEW process as a multi-tier system of support. This study investigated staff perceptions on integrated supports between schools and communities and identified the degree of relationship to school risk factors, school protective factors, and office discipline referrals following the building of cooperative partnerships between Systems of Care and Local Education Agencies.

    9. 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

    10. DExD-box RNA-helicases in Listeria monocytogenes are important for growth, ribosomal maturation, rRNA processing and virulence factor expression

      PubMed Central

      Bäreclev, Caroline; Vaitkevicius, Karolis; Netterling, Sakura; Johansson, Jörgen

      2014-01-01

      RNA-helicases are proteins required for the unwinding of occluding secondary RNA structures, especially at low temperatures. In this work, we have deleted all 4 DExD-box RNA helicases in various combinations in the Gram-positive pathogen Listeria monocytogenes. Our results show that 3 out of 4 RNA-helicases were important for growth at low temperatures, whereas the effect was less prominent at 37°C. Over-expression of one RNA-helicase, Lmo1450, was able to overcome the reduced growth of the quadruple mutant strain at temperatures above 26°C, but not at lower temperatures. The maturation of ribosomes was affected in different degrees in the various strains at 20°C, whereas the effect was marginal at 37°C. This was accompanied by an increased level of immature 23S rRNA precursors in some of the RNA-helicase mutants at low temperatures. Although the expression of the PrfA regulated virulence factors ActA and LLO decreased in the quadruple mutant strain, this strain showed a slightly increased infection ability. Interestingly, even though the level of the virulence factor LLO was decreased in the quadruple mutant strain as compared with the wild-type strain, the hly-transcript (encoding LLO) was increased. Hence, our results could suggest a role for the RNA-helicases during translation. In this work, we show that DExD-box RNA-helicases are involved in bacterial virulence gene-expression and infection of eukaryotic cells. PMID:25590644

    11. Development of a Validated LC Method for Separation of Process-Related Impurities Including the R-Enantiomer of S-Pramipexole on Polysaccharide Chiral Stationary Phases.

      PubMed

      Ramisetti, Nageswara Rao; Kuntamukkala, Ramakrishna; Arnipalli, Manikanta Swamy

      2015-07-01

      Despite the availability of a few methods for individual separation of S-pramipexole from its process-related impurities, no common liquid chromatography (LC) method is reported so far in the literature. The present article describes the development of a single-run LC method for simultaneous determination of S-pramipexole and its enantiomeric and process-related impurities on a Chiralpak AD-H (150 x 4.6 mm, 5μm) column using n-hexane/ethanol/n-butylamine (75:25:0.1 v/v/v) as a mobile phase in an isocratic mode of elution at a flow rate of 1.2 ml/min at 30°C. The chromatographic eluents were monitored at a wavelength of 260 nm using a photodiode array detector. Excellent enantioseparation with good resolutions (Rs ≥ 2.88) and peak shapes (As ≤ 1.21) for all analytes was achieved. The proposed method was validated according to International Conference Harmonization (ICH) guidelines in terms of accuracy, precision, sensitivity, and linearity. Limits of quantification of impurities (0.25-0.55 μg/ml) indicate the highest sensitivity achievable by the proposed method. The method has an advantage of selectivity and suitability for routine determination of not only chiral impurity but also all possible related substances in active pharmaceutical ingredients of S-pramipexole. PMID:25966024

    12. Particles, processes and materials for modern energy needs: Development of a DOE-EPSCoR project in Puerto Rico. Final report for September 30, 1997 - August 31, 2000

      SciTech Connect

      Weiner, Brad R.

      2000-09-29

      Twenty-eight (28) faculty researchers focused on High Energy Particle Physics, Novel Thin Film Materials for Optoelectronic Applications, and Catalytic Processes for Energy Sources and Environmental Detoxification to address problems cited as priorities by the DOE and local agencies. The High Energy Particle Physics cluster has DOE-competitive funding, and the number of cluster investigators who have competitive mainstream funding has increased from 2 to 13 since the inception of the program. In this reporting period, 8 postdoctorals, 38 graduate studnets, and 23 undergraduates were involved in DOE projects, and 191 publications and 238 presentations were generated. The UPR-Arecibo Integrated Science Multi-Use Laboratory provided workshops and other activities that directly impacted 360 teachers and 600 students and indirectly impacted over 25,000 through the enhancement of teachers' skills and knowledge.

    13. How Do People Become W.E.I.R.D.? Migration Reveals the Cultural Transmission Mechanisms Underlying Variation in Psychological Processes.

      PubMed

      Mesoudi, Alex; Magid, Kesson; Hussain, Delwar

      2016-01-01

      Cultural psychologists have shown that people from Western, Educated, Industrialised, Rich, Democratic (WEIRD) countries often exhibit different psychological processing to people from less-WEIRD countries. The former exhibit more individualistic and less collectivistic social orientation, and more analytic and less holistic cognition, than non-Westerners. Yet the mechanisms responsible for maintaining this cultural variation are unclear. Immigration is an ideal 'natural experiment' for uncovering such mechanisms. We used a battery of psychological measures previously shown to vary cross-culturally to compare the social orientation and cognitive style of 286 residents of East London from three cultural backgrounds: (i) 1st-generation British Bangladeshi immigrants; (ii) 2nd-generation British Bangladeshis raised in the UK to Bangladeshi-raised parents; and (iii) non-migrants whose parents were born and raised in the UK. Model comparison revealed that individualism and dispositional attribution, typical of Western societies, are driven primarily by horizontal cultural transmission (e.g. via mass media), with parents and other family members having little or no effect, while collectivism, social closeness and situational attribution were driven by a mix of vertical/oblique cultural transmission (e.g. via family contact) and horizontal cultural transmission. These individual-level transmission dynamics can explain hitherto puzzling population-level phenomena, such as the partial acculturation of 2nd-generation immigrants on measures such as collectivism (due to the mix of vertical and horizontal cultural transmission), or the observation in several countries of increasing individualism (which is transmitted horizontally and therefore rapidly) despite little corresponding change in collectivism (which is transmitted partly vertically and therefore more slowly). Further consideration of cultural transmission mechanisms, in conjunction with the study of migrant

    14. How Do People Become W.E.I.R.D.? Migration Reveals the Cultural Transmission Mechanisms Underlying Variation in Psychological Processes

      PubMed Central

      Mesoudi, Alex; Magid, Kesson; Hussain, Delwar

      2016-01-01

      Cultural psychologists have shown that people from Western, Educated, Industrialised, Rich, Democratic (WEIRD) countries often exhibit different psychological processing to people from less-WEIRD countries. The former exhibit more individualistic and less collectivistic social orientation, and more analytic and less holistic cognition, than non-Westerners. Yet the mechanisms responsible for maintaining this cultural variation are unclear. Immigration is an ideal ‘natural experiment’ for uncovering such mechanisms. We used a battery of psychological measures previously shown to vary cross-culturally to compare the social orientation and cognitive style of 286 residents of East London from three cultural backgrounds: (i) 1st-generation British Bangladeshi immigrants; (ii) 2nd-generation British Bangladeshis raised in the UK to Bangladeshi-raised parents; and (iii) non-migrants whose parents were born and raised in the UK. Model comparison revealed that individualism and dispositional attribution, typical of Western societies, are driven primarily by horizontal cultural transmission (e.g. via mass media), with parents and other family members having little or no effect, while collectivism, social closeness and situational attribution were driven by a mix of vertical/oblique cultural transmission (e.g. via family contact) and horizontal cultural transmission. These individual-level transmission dynamics can explain hitherto puzzling population-level phenomena, such as the partial acculturation of 2nd-generation immigrants on measures such as collectivism (due to the mix of vertical and horizontal cultural transmission), or the observation in several countries of increasing individualism (which is transmitted horizontally and therefore rapidly) despite little corresponding change in collectivism (which is transmitted partly vertically and therefore more slowly). Further consideration of cultural transmission mechanisms, in conjunction with the study of migrant

    15. Simulation of self-organization processes in crystal-forming systems: Supramolecular cyclic R6 cluster precursors and self-assembly of TeO2- TEL ( Tellurite) and TeO2- PAR ( Paratellurite) structures

      NASA Astrophysics Data System (ADS)

      Ilyushin, G. D.

      2014-11-01

      The supramolecular chemistry of oxides of sp elements (SO2, SeO2, and TeO2) is considered. The self-assembly of TeO2- TEL ( Tellurite) and TeO2- PAR ( Paratellurite) crystal structures is simulated. Methods of combinatorial and topological analysis (TOPOS program package) are applied which are based on constructing a basis 3D network of the structure in the form of a graph, the sites of which correspond to the positions of centroids of TeO2 molecules and the edges characterize bonds between them. The topological type of the basis 2D network in the TeO2- TEL structure corresponds to graphite (C- GRA), while in the TeO2- PAR structure the basis network corresponds to the 3D diamond network (C- DIA). A nanocluster precursor of cyclic type ( R6) composed of six covalently bound TeO2 molecules (chair conformation) is established for both structures. The desymmetrization of the cyclic structure of the R6 cluster in TeO2- PAR is related to the formation of Te-Te bonds with lengths of 3.824 and 4.062 Å. The symmetry and topology code of the processes of self-assembly of 3D structures from nanocluster precursors is completely reconstructed into the form "primary chain → microlayer → microframework." In both structures R6 clusters form 2D packings with a coordination number of 6. The cluster self-assembly model explains the specific features of the morphogenesis of TeO2- TEL and TeO2- PAR (phases with low and high crystallization temperatures, respectively): platelike shape, perfect cleavage in the (110) plane, and preferred growth in the primar-chain direction [100] in the former case and growth in the direction of the primary [001] axis with the preferred formation of tetragonal prism faces (110) in the latter case.

    16. Detailed Description of the GOES-R Space Weather Medium- and High-Energy Particle Instruments and Their Data Processing Algorithms with Applications to Expected On-Orbit Performance

      NASA Astrophysics Data System (ADS)

      Dichter, B. K.; Galica, G. E.; Tsui, S.; Golightly, M. J.

      2015-12-01

      The space weather instruments (Space Environment In-Situ Suite - SEISS) on the soon to be launched, NOAA GOES-R spacecraft offer significant performance advances over the previous GOES N-O series instruments. The medium- and high-energy particle instruments, MPS-HI and SGPS, measure differential proton spectra from 80 keV to 500 MeV in a total of 21 logarithmically spaced channels and electrons from 50 keV to 10 MeV in 10 logarithmically spaced channels. These instruments use solid state silicon detectors as sensor. Their designs feature multi-detector coincidence telescopes, combined with degrader material, tungsten shielding and data processing algorithms to optimize the signal to noise ratio. Details of the mechanical and electronic design will be presented. Key aspects of data processing including background subtraction techniques and a novel method to distinguish high energy rear entry particles from front entry ones will be described. Results of extensive modeling with GEANT4 will be compared with calibration data measured over nearly the entire energy range of the instruments. Combination of the two will be used to calculate the geometric factors of the various energy channels. A listing of the channels and their properties will be presented. The calibrated geometric factors and typical and extreme space weather environments will be used to calculate the expected on-orbit performance. The specifications that the instruments met ensure proper operation under the most stressful high flux conditions corresponding to the largest solar particle event expected during the program and high sensitivity at low flux levels. Comparisons will be made between the enhanced GOES-R instruments and the current GOES space weather measurement capabilities.

    17. Dynamics of R1 and R2 elements in the rDNA locus of Drosophila simulans.

      PubMed Central

      Pérez-González, C E; Eickbush, T H

      2001-01-01

      The mobile elements R1 and R2 insert specifically into the rRNA gene locus (rDNA locus) of arthropods, a locus known to undergo concerted evolution, the recombinational processes that preserve the sequence homogeneity of all repeats. To monitor how rapidly individual R1 and R2 insertions are turned over in the rDNA locus by these processes, we have taken advantage of the many 5' truncation variants that are generated during the target-primed reverse transcription mechanism used by these non-LTR retrotransposons for their integration. A simple PCR assay was designed to reveal the pattern of the 5' variants present in the rDNA loci of individual X chromosomes in a population of Drosophila simulans. Each rDNA locus in this population was found to have a large, unique collection of 5' variants. Each variant was present at low copy number, usually one copy per chromosome, and was seldom distributed to other chromosomes in the population. The failure of these variants to spread to other units in the same rDNA locus suggests a strong recombinational bias against R1 and R2 that results in the individual copies of these elements being rapidly lost from the rDNA locus. This bias suggests a significantly higher frequency of R1 and R2 retrotransposition than we have previously suggested. PMID:11514447

    18. CONSTRUAL PROCESSES IN PREFERENCE ELICITATION. (R824706)

      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...

    19. fslr: Connecting the FSL Software with R

      PubMed Central

      Muschelli, John; Sweeney, Elizabeth; Lindquist, Martin; Crainiceanu, Ciprian

      2016-01-01

      We present the package fslr, a set of R functions that interface with FSL (FMRIB Software Library), a commonly-used open-source software package for processing and analyzing neuroimaging data. The fslr package performs operations on ‘nifti’ image objects in R using command-line functions from FSL, and returns R objects back to the user. fslr allows users to develop image processing and analysis pipelines based on FSL functionality while interfacing with the functionality provided by R. We present an example of the analysis of structural magnetic resonance images, which demonstrates how R users can leverage the functionality of FSL without switching to shell commands. PMID:27330830

    20. 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...

    1. 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.

    2. RSEIS and RFOC: Seismic Analysis in R

      NASA Astrophysics Data System (ADS)

      Lees, J. M.

      2015-12-01

      Open software is essential for reproducible scientific exchange. R-packages provide a platform for development of seismological investigation software that can be properly documented and traced for data processing. A suite of R packages designed for a wide range of seismic analysis is currently available in the free software platform called R. R is a software platform based on the S-language developed at Bell Labs decades ago. Routines in R can be run as standalone function calls, or developed in object-oriented mode. R comes with a base set of routines, and thousands of user developed packages. The packages developed at UNC include subroutines and interactive codes for processing seismic data, analyzing geographic information (GIS) and inverting data involved in a variety of geophysical applications. On CRAN (Comprehensive R Archive Network, http://www.r-project.org/) currently available packages related to seismic analysis are RSEIS, Rquake, GEOmap, RFOC, zoeppritz, RTOMO, and geophys, Rwave, PEIP, hht, rFDSN. These include signal processing, data management, mapping, earthquake location, deconvolution, focal mechanisms, wavelet transforms, Hilbert-Huang Transforms, tomographic inversion, and Mogi deformation among other useful functionality. All software in R packages is required to have detailed documentation, making the exchange and modification of existing software easy. In this presentation, I will focus on packages RSEIS and RFOC, showing examples from a variety of seismic analyses. The R approach has similarities to the popular (and expensive) MATLAB platform, although R is open source and free to down load.

    3. Intrusive [r] and Optimal Epenthetic Consonants

      ERIC Educational Resources Information Center

      Uffmann, Christian

      2007-01-01

      This paper argues against the view of intrusive [r] as a synchronically arbitrary insertion process. Instead, it is seen as a phonologically natural process, which can be modelled within the framework of Optimality Theory (OT). Insertion of [r] in phonologically restricted environments is a consequence of a more general theory of consonant…

    4. Microbial community analysis in the denitrification process of saline-wastewater by denaturing gradient gel electrophoresis of PCR-amplified 16S rDNA and the cultivation method.

      PubMed

      Yoshie, S; Noda, N; Miyano, T; Tsuneda, S; Hirata, A; Inamori, Y

      2001-01-01

      The metallurgic wastewater generated from the processes of recovering precious metals from industrial wastes contains high concentrations of nitrogen compounds and salts. Biological nitrogen removal from this wastewater was attempted using a circulating bioreactor system equipped with an anaerobic packed bed or an anaerobic fluidized bed. The denitrification capability of the system with the anaerobic packed bed was more stable than that of the system with the anaerobic fluidized bed. The NOx removal rate of the anaerobic packed bed was as high as 97%. Microbial community analysis by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA (rDNA) fragments and the cultivation method revealed that the community diversity varied in accordance with wastewater composition such as the level of salinity and so on. Phylogenetic analysis suggested that the taxonomic affiliation of the dominant species in the anaerobic reactors was to the gamma-Proteobacteria including Halomonadaceae species. The PCR-DGGE method as a non-cultivation method was found to be a powerful tool for analysis of the microbial community, because the cultivation method could detect only a fraction of the microbial species present in these systems. The genetic diversity of the isolated bacteria belonging to the gamma-Proteobacteria which reduced both nitrate and nitrite in the anaerobic packed bed was higher than that of the bacteria in the anaerobic fluidized bed. This suggested that a genetically diverse microbial community stabilized the denitrifying performance in the anaerobic packed bed. PMID:16233109

    5. 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.

    6. β -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

      SciTech Connect

      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 β -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,γ)⇌(γ,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.

    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

    8. Inside H. R. 226

      SciTech Connect

      Pontius, F.W.

      1995-03-01

      Among legislation introduced on the first day of the 104th Congress was H.R. 226, a Safe Drinking Water Act (SDWA) reauthorization bill. The bill was introduced to serve as a starting point for reauthorization. The bill would substantially change the SDWA regulatory process. Under its provisions the US Environmental Protection Agency (USEPA) would be required to publish within one year of the bill's enactment a proposed list of at least 15 contaminants that may occur in public water systems and that are not currently subject to regulation. A proposed list of at least 12 additional contaminants would be required every four years. The requirement to select an additional 12 contaminants would be waived after 2010 if the agency determined the number of unregulated contaminants meeting the listing criteria to be less than 12. A final list would have to be published no later than one year after publication of the proposed list.

    9. Mutated hybrid inflation in f(R,squareR)-gravity

      NASA Astrophysics Data System (ADS)

      Iihoshi, Masao

      2011-02-01

      A new hybrid inflationary scenario in the context of f(R,squareR)-gravity is proposed. Demanding the waterfall field to `support the potential from below' [unlike the original proposal by Stewart in Phys. Lett. B 345, 414 (1995)], we demonstrate that the scalar potential is similar to that of the large-field chaotic inflation model proposed by Linde in Phys. Lett. B 129, 177 (1983). Inflationary observables are used to constrain the parameter space of our model; in the process, an interesting limit on the number of e-folds N is found.

    10. Mutated hybrid inflation in f(R,□R)-gravity

      SciTech Connect

      Iihoshi, Masao

      2011-02-01

      A new hybrid inflationary scenario in the context of f(R,□R)-gravity is proposed. Demanding the waterfall field to 'support the potential from below' [unlike the original proposal by Stewart in Phys. Lett. B 345, 414 (1995)], we demonstrate that the scalar potential is similar to that of the large-field chaotic inflation model proposed by Linde in Phys. Lett. B 129, 177 (1983). Inflationary observables are used to constrain the parameter space of our model; in the process, an interesting limit on the number of e-folds N is found.

    11. 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

    12. Does R&D pay?

      PubMed

      Cavalla, David; Minhas, Raman

      2010-03-01

      Pharmaceutical R&D is notoriously risky, lengthy and costly; moreover, it does not always produce products of blockbuster status. The conventional route of fully discovering, developing and marketing a new chemical entity is followed by the large pharmaceutical companies, whereas other organizations in the pharmaceutical sector--such as generic or specialty companies and biotechnology companies--only operate over portions of the full R&D process. Here, we compare the ten-year financial performance of these three subsectors through their price/earnings ratios and their return on capital metrics to understand which of these strategic alternatives offered the best return to investors. PMID:19931643

    13. Multispecies TASEP and combinatorial R

      NASA Astrophysics Data System (ADS)

      Kuniba, Atsuo; Maruyama, Shouya; Okado, Masato

      2015-08-01

      We identify the algorithm for constructing steady states of the n-species totally asymmetric simple exclusion process (TASEP) on an L site periodic chain by Ferrari and Martin with a composition of combinatorial R for the quantum affine algebra {U}q({\\widehat{{sl}}}L) in crystal base theory. Based on this connection and the factorized form of the R matrix derived recently from the tetrahedron equation, we establish a new matrix product formula for the steady state of the TASEP, which is expressed in terms of corner transfer matrices of the q-oscillator valued five-vertex model at q = 0. Dedicated to the memory of Professor Ryogo Hirota.

    14. 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

    15. 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…

    16. miR-122, a mammalian liver-specific microRNA, is processed from hcr mRNA and may downregulate the high affinity cationic amino acid transporter CAT-1.

      PubMed

      Chang, Jinhong; Nicolas, Emmanuelle; Marks, Debora; Sander, Chris; Lerro, Anthony; Buendia, Marie Annick; Xu, Chunxiao; Mason, William S; Moloshok, Thomas; Bort, Roque; Zaret, Kenneth S; Taylor, John M

      2004-07-01

      These studies show that miR-122, a 22-nucleotide microRNA, is derived from a liver-specific noncoding polyadenylated RNA transcribed from the gene hcr. The exact sequence of miR-122 as well as the adjacent secondary structure within the hcr mRNA are conserved from mammalian species back to fish. Levels of miR-122 in the mouse liver increase to half maximal values around day 17 of embryogenesis, and reach near maximal levels of 50,000 copies per average cell before birth. Lewis et al. (2003) predicted the cationic amino acid transporter (CAT-1 or SLC7A1) as a miR-122 target. CAT-1 protein and its mRNA are expressed in all mammalian tissues but with lower levels in adult liver. Furthermore, during mouse liver development CAT-1 mRNA decreases in an almost inverse correlation with miR-122. Eight potential miR-122 target sites were predicted within the human CAT-1 mRNA, with six in the 3'-untranslated region. Using a reporter construct it was found that just three of the predicted sites, linked in a 400-nucleotide sequence from human CAT-1, acted with synergy and were sufficient to strongly inhibit protein synthesis and reduce mRNA levels. In summary, these studies followed the accumulation during development of miR-122 from its mRNA precursor, hcr, through to identification of what may be a specific mRNA target, CAT-1. PMID:17179747

    17. Dielectric Constants of Refrigerants R113, R114, R114B2, R115, R116, and R124

      NASA Astrophysics Data System (ADS)

      Kashiwagi, Hiroshi; Harada, Noboru; Tanaka, Yoshiyuki; Kubota, Hironobu; Makita, Tadashi

      The dielectric constants of six refrigerants have been measured in both gaseous and liquid phases. The fluids used and the experimental ranges of temperature and pressure are as follows : R113 (1, 2, 2- Trichlorotrifluoroethane CClF2CCl2F) : 298.15-423.15K, 0.1-17.3MPa, R1l4 (1, 2- Dichlorotetrafluoroethane CClF2CClF2) : 298.15-423.15K, 0.2-17.2MPa, R114B2 (1, 2- Dibromotetrafluoroethane CBrF2CBrF2) : 298.15-423.15K, 0.2-17.3MPa, R1l5 (Chloropentafluoroethane CClF2CF3) : 298.15 373.15K. O.1-17.1MPa, R1l6 (Hexafluoroethane CF3CF3) : 283.15-373.15 K, 0.2-16.9MPa, R124 (1-Chloro-2, 2, 2, -tetrafluoroethane CHClFCF3) : 273.15 373.15K, 0.1-10.5MPa The measurements were performed using a frequency-counting method on a relative basis with an uncertainty less than ±0.1%.The experimental results are given by polynomial equations. The smoothed value tables are also given for practical convenience. The pressure dependence of dielectric constants in liquid phase is represented by a similar expression to the Tait equation. The effects of pressure, temperature, and density on the dielectric constant and the molar polarization defined by the Clausius-Mossotti relation are discussed in term of polarity of molecules of each refrigerant.

    18. 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...

    19. 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

      ... of Devils Lake, ND (76 FR 72869). Interested parties were invited to participate in this rulemaking... the comment period for 30 additional days (77 FR 1656; January 11, 2012). There were 43 comments... environmental impacts associated with the proposed creation of Restricted Areas R-5402, R-5403A, R-5403B,...

    20. 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}.

    1. 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.

    2. Evaluation of Z-(R,R)-IQNP for the potential imaging of m2 mAChR rich regions of the brain and heart.

      PubMed

      McPherson, D W; Greenbaum, M; Luo, H; Beets, A L; Knapp, F F

      2000-01-01

      Alterations in the function or density of the m2 muscarinic (mAChR) subtype have been postulated to play an important role in various dementias such as Alzheimer's disease. The ability to image and quantify the m2 mAChR subtype is of importance for a better understanding of the m2 subtype function in various dementias. Z-(R)-1-Azabicyclo[2.2.2]oct-3-y (R)-alpha-hydroxy-alpha-(1-iodo-1-propen-3-yl)-alpha-phenylacetate (Z-(R,R)-IQNP) has demonstrated significant uptake in cerebral regions that contain a high concentration of m2 mAChR subtype in addition to heart tissue. The present study was undertaken to determine if the uptake of Z-(R,R)-IQNP in these regions is a receptor mediated process and to identify the radiospecies responsible for binding at the receptor site. A blocking study demonstrated cerebral and cardiac levels of activity were significantly reduced by pretreatment (2-3 mg/kg) of (R)-3-quinuclidinyl benzilate, dexetimide and scopolamine, established muscarinic antagonists. A direct comparison of the cerebral and cardiac uptake of [I-125]-Z-(R,R)-IQNP and [I-131]-E-(R,R)-IQNP (high uptake in ml, m4 rich mAChR cerebral regions) demonstrated Z-(R,R)-IQNP localized to a higher degree in cerebral and cardiac regions containing a high concentration of the m2 mAChR subtype as directly compared to E-(R,R)-IQNP. In addition, a study utilizing [I-123]-Z-(R,R)-IQNP, [I-131]-iododexetimide and [I-125]-R-3-quinuclidinyl S-4-iodobenzilate, Z-(R,R)-IQNP demonstrated significantly higher uptake and longer residence time in those regions which contain a high concentration of the m2 receptor subtype. Folch extraction of global brain and heart tissue at various times post injection of [I-125]-Z-(R,R)-IQNP demonstrated that approximately 80% of the activity was extracted in the lipid soluble fraction and identified as the parent ligand by TLC and HPLC analysis. These results demonstrate Z-(R,R)-IQNP has significant uptake, long residence time and high stability in

    3. R+R2 gravity as R+ back reaction

      NASA Astrophysics Data System (ADS)

      Kung, J. H.

      1995-12-01

      The quadratic theory of gravity is a complicated constraint system. We investigate some consequences of treating quadratic terms perturbatively (higher derivative version of back reaction effects), which is consistent with the way the existence of quadratic terms was originally established (radiative loop effects and renormalization procedures which induced quadratic terms). We show that this approach overcomes some well-known problems associated with higher derivative theories, i.e., the physical gravitational degree of freedom remains unchanged from those of Einstein gravity. Using such an approach we first study the classical cosmology of R+βR2 theory coupled to matter with a characteristic ρ~a(t)-n dependence on the scale factor. We show that for n>4 (i.e., p>1/3ρ) and for a particular sign of β, corresponding to the nontachyon case, there is no big bang in the traditional sense. And, therefore, a contracting FRW universe (k>0, k=0, k<0) will rebounce to an expansion phase without a total gravitational collapse. We then quantize the corresponding minisuperspace model that resulted from treating the βR2 as a perturbation. We conclude that the potential W(a), in the Wheeler-De Witt equation [-∂2/∂a2+2W(a)]ψ(a)=0, develops a repulsive barrier near a~=0 again for n>4 (i.e., p>1/3ρ) and for the sign of β that corresponds to the nontachyon case. Since a~=0 is a classically forbidden region, the probability of finding a universe with a singularity (a=0) is exponentially suppressed. Unlike the quantum cosmology of Einstein's gravity, the formalism has dictated an appropriate boundary (initial) condition. Classical and quantum analyses demonstrate that a minimum radius of collapse increases for a larger value of ||β||. It is also shown that, to first order in β, the βR2 term has no effect during the radiation (p=1/3ρ) and inflationary (p=-ρ) era. Therefore, a de Sitter phase can be readily generated by incorporating a scalar field.

    4. 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.

    5. 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.

      PubMed

      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

      2013-10-31

      The atmospheric processing of (E)- and (Z)-1,2-dichlorohexafluoro-cyclobutane (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((1)D) + R-316c reaction, i.e., O((1)D) loss, was measured to be (1.56 ± 0.11) × 10(-10) cm(3) molecule(-1) s(-1) and the reactive rate coefficient, i.e., R-316c loss, was measured to be (1.36 ± 0.20) × 10(-10) cm(3) molecule(-1) s(-1) corresponding to a ~88% reactive yield. Rate coefficient upper-limits for the OH and O3 reaction with R-316c were determined to be <2.3 × 10(-17) and <2.0 × 10(-22) cm(3) molecule(-1) s(-1), respectively, at 296 K. The quoted uncertainty limits are 2σ 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((1)D) reaction making a minor, ~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

    6. 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

    7. 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…

    8. Genome-Wide Identification and Characterization of R2R3MYB Family in Cucumis sativus

      PubMed Central

      Li, Qiang; Zhang, Cunjia; Li, Jing; Wang, Lina; Ren, Zhonghai

      2012-01-01

      Background The R2R3MYB proteins comprise one of the largest families of transcription factors in plants. Although genome-wide analysis of this family has been carried out in some species, little is known about R2R3MYB genes in cucumber (Cucumis sativus L.). Principal Findings This study has identified 55 R2R3MYB genes in the latest cucumber genome and the CsR2R3MYB family contained the smallest number of identified genes compared to other species that have been studied due to the absence of recent gene duplication events. These results were also supported by genome distribution and gene duplication analysis. Phylogenetic analysis showed that they could be classified into 11 subgroups. The evolutionary relationships and the intron - exon organizations that showed similarities with Arabidopsis, Vitis and Glycine R2R3MYB proteins were also analyzed and suggested strong gene conservation but also the expansions of particular functional genes during the evolution of the plant species. In addition, we found that 8 out of 55 (∼14.54%) cucumber R2R3MYB genes underwent alternative splicing events, producing a variety of transcripts from a single gene, which illustrated the extremely high complexity of transcriptome regulation. Tissue-specific expression profiles showed that 50 cucumber R2R3MYB genes were expressed in at least one of the tissues and the other 5 genes showed very low expression in all tissues tested, which suggested that cucumber R2R3MYB genes took part in many cellular processes. The transcript abundance level analysis during abiotic conditions (NaCl, ABA and low temperature treatments) identified a group of R2R3MYB genes that responded to one or more treatments. Conclusions This study has produced a comparative genomics analysis of the cucumber R2R3MYB gene family and has provided the first steps towards the selection of CsR2R3MYB genes for cloning and functional dissection that can be used in further studies to uncover their roles in cucumber growth and

    9. Materials Science and Technology, Volume 15, Materials Science and Technology A Comprehensive Treatment - Volume 15: Processing of Metals and Alloys Cahn,R.W.(ed.)/Haasen,P.(ed.)/Kramer,E.J.(ed.)

      NASA Astrophysics Data System (ADS)

      Cahn, Robert W.

      1996-12-01

      The properties of metals and alloys, and thus their effectiveness in applications, are closely related to the processing methods applied. Metallurgists and other technologists involved with metals and alloys are provided with a unique overview of processing techniques and their effects. From the Contents: Flemings: Solidification Processing. Suryanarayana: Rapid Solidification. Mordike: Surface Modification by Lasers. Arunachalam/Sundaresan: Powder Metallurgy. Koch: Mechanical Milling and Alloying. Follstaedt: Ion Implantation and Ion-Beam Mixing. Pashley: The Epitaxy of Metals. Somekh/Greer: Metallic Multilayers. Humphreys: Recrystallization and Recovery. Cahn: Measurement and Control of Texture. de Bonte/Roos/Celis: Electrodeposition of Metals and Alloys. Sahm/Keller: Solidification Processing Under Microgravity. Siegel: Cluster Assembly of Nanophase Materials.

    10. MiR-1246

      PubMed Central

      Liao, Jun-Ming; Zhou, Xiang; Zhang, Yu; Lu, Hua

      2012-01-01

      Since the discovery of miRNAs, a number of miRNAs have been identified as p53’s transcriptional targets. Most of them are involved in regulation of the known p53 functions, such as cell cycle, apoptosis and senescence. Our recent study revealed miR-1246 as a novel target of p53 and its analogs p63 and p73 to suppress the expression of DYRK1A and consequently activate NFAT, both of which are associated with Down syndrome and possibly with tumorigenesis. This finding suggests that miR-1246 might serve as a likely link of the p53 family with Down syndrome. Here, we provide some prospective views on the potential role of the p53 family in Down syndrome via miR-1246 and propose a new p53-miR-1246-DYRK1A-NFAT pathway in cancer. PMID:22751441

    11. 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.

    12. Unconscious Priming According to Multiple S-R Rules

      ERIC Educational Resources Information Center

      Kiesel, Andrea; Kunde, Wilfried; Hoffmann, Joachim

      2007-01-01

      The present study investigated if unconscious primes can be processed according to different stimulus-response (S-R) rules simultaneously. Participants performed two different S-R rules, such as judging a digit as smaller or larger than five and judging a letter as vowel or consonant. These S-R rules were administered in random order and announced…

    13. 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.

    14. Research on R&D Project Risk Management Model

      NASA Astrophysics Data System (ADS)

      Gu, Xiaoyan; Cai, Chen; Song, Hao; Song, Juan

      R&D project is an exploratory high-risk investment activity and has potential management flexibility. In R&D project risk management process, it is hard to quantify risk with very little past information available. This paper introduces quality function deployment and real option in traditional project risk management process. Through waterfall decomposition mode, R&D project risk management process is constructed step by step; through real option, the managerial flexibility inherent in R&D project can be modeled. In the paper, first of all, according to the relation matrix between R&D project success factors and risk indexes, risk priority list can be obtained. Then, risk features of various stages are analyzed. Finally, real options are embedded into various stages of R&D project by the risk features. In order to effectively manage R&D risk in a dynamic cycle, the steps above should be carried out repeatedly.

    15. QuasR: quantification and annotation of short reads in R

      PubMed Central

      Gaidatzis, Dimos; Lerch, Anita; Hahne, Florian; Stadler, Michael B.

      2015-01-01

      Summary: QuasR is a package for the integrated analysis of high-throughput sequencing data in R, covering all steps from read preprocessing, alignment and quality control to quantification. QuasR supports different experiment types (including RNA-seq, ChIP-seq and Bis-seq) and analysis variants (e.g. paired-end, stranded, spliced and allele-specific), and is integrated in Bioconductor so that its output can be directly processed for statistical analysis and visualization. Availability and implementation: QuasR is implemented in R and C/C++. Source code and binaries for major platforms (Linux, OS X and MS Windows) are available from Bioconductor (www.bioconductor.org/packages/release/bioc/html/QuasR.html). The package includes a ‘vignette’ with step-by-step examples for typical work flows. Contact: michael.stadler@fmi.ch Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25417205

    16. Parts-R-Us

      NASA Astrophysics Data System (ADS)

      Brunvand, Erik

      1987-12-01

      Parts-R-Us is a chip that contains a collection of building block parts for asynchronous circuit design. The parts contained on the chip are either not available as standard commercial components, or are standard gates combined into small modules that are particularly useful for building asynchronous control circuits. There are eight different configurations of Parts-R-Us, each offering a different set of asynchronous parts to the user. The parts contained on the chip include: C-elements, transition call modules, transition selectors, transition toggles, transition arbiters, a four phase mutual exclusion element, an asynchronous register, two phase Q-registers, and four phase Q-registers. This document is both a description of Parts-R-Us, and a user's manual for designers using the chip.

    17. 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

    18. 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

    19. 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…

    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. Use of rRNA gene restriction patterns to evaluate lactic acid bacterium contamination of vacuum-packaged sliced cooked whole-meat product in a meat processing plant.

      PubMed Central

      Björkroth, K J; Korkeala, H J

      1997-01-01

      Molecular typing was applied to an in-plant lactic acid bacterium (LAB) contamination analysis of a vacuum-packaged sliced cooked whole-meat product. A total of 982 LAB isolates from the raw mass, product, and the environment at different production stages were screened by restriction endonuclease (EcoRI and HindIII) analysis. rRNA gene restriction patterns were further determined for different strains obtained from each source. These patterns were used for recognizing the spoilage-causing LAB strains from the product on the sell-by day and tracing the sources and sites of spoilage LAB contamination during the manufacture. LAB typing resulted in 71 different ribotypes, of which 27 were associated with contamination routes. Raw material was distinguished as the source of the major spoilage strains. Contamination of the product surfaces after cooking was shown to be airborne. The removal of the product from the cooking forms was localized as a major site of airborne LAB contamination. Food handlers and some surfaces in contact with the product during the manufacture were also contaminated with the spoilage strains. Some LAB strains were also able to resist cooking in the core of the product bar. These strains may have an effect on the product shelf life by contaminating the slicing machine. The air in the slicing department and adjacent cold room contained very few LAB. Surface-mediated contamination was detected during the slicing and packaging stages. Food handlers also carried strains later found in the packaged product. Molecular typing provided useful information revealing the LAB contamination sources and sites of this product. The production line will be reorganized in accordance with these results to reduce spoilage LAB contamination. PMID:9023922

    2. XagR, a LuxR homolog, contributes to the virulence of Xanthomonas axonopodis pv. glycines to soybean.

      PubMed

      Chatnaparat, Tiyakhon; Prathuangwong, Sutruedee; Ionescu, Michael; Lindow, Steven E

      2012-08-01

      A novel luxR homolog, termed XagR, in Xanthomonas axonopodis pv. glycines, the cause of soybean pustule, controls expression of pip, yapH, and at least 77 other genes. Although XagR and Pip are required for full virulence of X. axonopodis pv. glycines to soybean, constitutive overproduction of XagR suppresses infection. The xagR-dependent induction of pip occurs in planta only 2 days or more after inoculation. Although the transcription of xagR appears constitutive, XagR accumulates only in cells that have colonized soybean plants for more than 2 days suggesting that some components produced during the infection process mediate post-transcriptional control, likely by protecting XagR from proteolytic degradation. XagR modulates the adhesiveness of the pathogen during the infection process by suppressing the adhesin YapH. Although yapH mutants incite more infections of soybean leaves than the wild-type strain when topically applied under dry conditions, the mutant causes fewer infections when leaves are subject to simulated rain events after inoculation. Likewise, yapH mutants and cells in which XagR was overexpressed exhibited much more egress from infected leaves than the wild-type strain. Thus, XagR differentially modulates expression of a variety of genes during the infection process in response to feedback from plant molecules elaborated during infection to coordinate processes such as invasion, infection, and cell egress needed to complete the disease cycle. PMID:22746827

    3. Competitive regulation of nucleolin expression by HuR and miR-494.

      PubMed

      Tominaga, Kumiko; Srikantan, Subramanya; Lee, Eun Kyung; Subaran, Sarah S; Martindale, Jennifer L; Abdelmohsen, Kotb; Gorospe, Myriam

      2011-10-01

      The RNA-binding protein (RBP) nucleolin promotes the expression of several proliferative proteins. Nucleolin levels are high in cancer cells, but the mechanisms that control nucleolin expression are unknown. Here, we show that nucleolin abundance is controlled posttranscriptionally via factors that associate with its 3' untranslated region (3'UTR). The RBP HuR was found to interact with the nucleolin (NCL) 3'UTR and specifically promoted nucleolin translation without affecting nucleolin mRNA levels. In human cervical carcinoma HeLa cells, analysis of a traceable NCL 3'UTR bearing MS2 RNA hairpins revealed that NCL RNA was mobilized to processing bodies (PBs) after silencing HuR, suggesting that the repression of nucleolin translation may occur in PBs. Immunoprecipitation of MS2-tagged NCL 3'UTR was used to screen for endogenous repressors of nucleolin synthesis. This search identified miR-494 as a microRNA that potently inhibited nucleolin expression, enhanced NCL mRNA association with argonaute-containing complexes, and induced NCL RNA transport to PBs. Importantly, miR-494 and HuR functionally competed for modulation of nucleolin expression. Moreover, the promotion of cell growth previously attributed to HuR was due in part to the HuR-elicited increase in nucleolin expression. Our collective findings indicate that nucleolin expression is positively regulated by HuR and negatively regulated via competition with miR-494. PMID:21859890

    4. MiR-221 and miR-130a Regulate Lung Airway and Vascular Development

      PubMed Central

      Mujahid, Sana

      2013-01-01

      Epithelial-mesenchymal interactions play a crucial role in branching morphogenesis, but very little is known about how endothelial cells contribute to this process. Here, we examined how anti-angiogenic miR-221 and pro-angiogenic miR-130a affect airway and vascular development in the fetal lungs. Lung-specific effects of miR-130a and miR-221 were studied in mouse E14 whole lungs cultured for 48 hours with anti-miRs or mimics to miR-130a and miR-221. Anti-miR 221 treated lungs had more distal branch generations with increased Hoxb5 and VEGFR2 around airways. Conversely, mimic 221 treated lungs had reduced airway branching, dilated airway tips and decreased Hoxb5 and VEGFR2 in mesenchyme. Anti-miR 130a treatment led to reduced airway branching with increased Hoxa5 and decreased VEGFR2 in the mesenchyme. Conversely, mimic 130a treated lungs had numerous finely arborized branches extending into central lung regions with diffusely localized Hoxa5 and increased VEGFR2 in the mesenchyme. Vascular morphology was analyzed by GSL-B4 (endothelial cell-specific lectin) immunofluorescence. Observed changes in airway morphology following miR-221 inhibition and miR-130a enhancement were mirrored by changes in vascular plexus formation around the terminal airways. Mouse fetal lung endothelial cells (MFLM-91U) were used to study microvascular cell behavior. Mimic 221 treatment resulted in reduced tube formation and cell migration, where as the reverse was observed with mimic 130a treatment. From these data, we conclude that miR-221 and miR-130a have opposing effects on airway and vascular morphogenesis of the developing lung. PMID:23409087

    5. James R. Thompson

      NASA Technical Reports Server (NTRS)

      1986-01-01

      James R. Thompon served as director of the Marshall Space Flight Center from September 29, 1986 until July 6, 1989, when he was appointed as NASA Deputy Administrator. Prior to his tenure as Marshall's Director, Thompson served from March to June 1986 as the vice-chairman of the NASA task force investigating the cause of the Space Shuttle Challenger accident. He was credited with playing a significant role in returning the Space Shuttle to flight following the Challenger disaster.

    6. 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;…

    7. CP3R: An Important Tool.

      PubMed

      Clark, Danette; Clark, Danillie

      2016-01-01

      The Web-based Cancer Program Practice Profile Reports (CP3R) offer providers comparative information to assess adherence to and consideration of standard-of-care therapies for major cancers. The tool helps facilities practice continuous improvement to ensure quality of patient care. The poster will illustrate a process to ensure the presentation of data at a compliance level. PMID:27556847

    8. miR-210 promotes osteoblastic differentiation through inhibition of AcvR1b.

      PubMed

      Mizuno, Yosuke; Tokuzawa, Yoshimi; Ninomiya, Yuichi; Yagi, Ken; Yatsuka-Kanesaki, Yukiko; Suda, Tatsuo; Fukuda, Toru; Katagiri, Takenobu; Kondoh, Yasumitsu; Amemiya, Tomoyuki; Tashiro, Hideo; Okazaki, Yasushi

      2009-07-01

      Although microRNAs (miRNAs) are involved in many biological processes, the mechanisms whereby miRNAs regulate osteoblastic differentiation are poorly understood. Here, we found that BMP-4-induced osteoblastic differentiation of bone marrow-derived ST2 stromal cells was promoted and repressed after transfection of sense and antisense miR-210, respectively. A reporter assay demonstrated that the activin A receptor type 1B (AcvR1b) gene was a target for miR-210. Furthermore, inhibition of transforming growth factor-beta (TGF-beta)/activin signaling in ST2 cells with SB431542 promoted osteoblastic differentiation. We conclude that miR-210 acts as a positive regulator of osteoblastic differentiation by inhibiting the TGF-beta/activin signaling pathway through inhibition of AcvR1b. PMID:19520079

    9. Hydrologic Tests at Characterization Wells R-9i, R-13, R-19, R-22, and R-31, Revision 1

      SciTech Connect

      S.G.McLin; W.J. Stone

      2004-06-01

      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. Field tests were conducted 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 new wells: R-9i, R-13, R-19, R-22, and R-31. One well (R-13) was evaluated by a pumping test and the rest (R-9i, R-19, R-22, and R-31) were evaluated by injection tests. Characterization well R-9i is located in Los Alamos Canyon approximately 0.3 mi west of the Route 4/Route 502 intersection. It was completed at a depth of 322 ft below ground surface (bgs) in March 2000. This well was constructed with two screens positioned below the regional water table. Both screens were tested. Screen 1 is completed at about 189-200 ft bgs in fractured basalt, and screen 2 is completed at about 270-280 ft bgs in massive basalt. Specific capacity analysis of the screen 1 data suggests that the fractured basalt has a transmissivity (T) of 589 ft{sup 2}/day and corresponds to a hydraulic conductivity (K) of 7.1 ft/day based on a saturated thickness of 83 ft. The injection test data from the massive basalt near screen 2 were analyzed by the Bouwer-Rice slug test methodology and suggest that K is 0.11 ft/day, corresponding to a T of about 2.8 ft{sup 2}/day based on a saturated thickness of 25 ft. Characterization well R-13 is located in Mortandad Canyon just west of the eastern Laboratory boundary. It was completed at a depth of 1029 ft bgs in February 2002. This well was constructed with one 60-ft long screen positioned about 125 ft below the regional water table. This screen is completed at about 958-1019 ft bgs and straddles the geologic contact

    10. Decision tree modeling using R

      PubMed Central

      2016-01-01

      In machine learning field, decision tree learner is powerful and easy to interpret. It employs recursive binary partitioning algorithm that splits the sample in partitioning variable with the strongest association with the response variable. The process continues until some stopping criteria are met. In the example I focus on conditional inference tree, which incorporates tree-structured regression models into conditional inference procedures. While growing a single tree is subject to small changes in the training data, random forests procedure is introduced to address this problem. The sources of diversity for random forests come from the random sampling and restricted set of input variables to be selected. Finally, I introduce R functions to perform model based recursive partitioning. This method incorporates recursive partitioning into conventional parametric model building. PMID:27570769

    11. Decision tree modeling using R.

      PubMed

      Zhang, Zhongheng

      2016-08-01

      In machine learning field, decision tree learner is powerful and easy to interpret. It employs recursive binary partitioning algorithm that splits the sample in partitioning variable with the strongest association with the response variable. The process continues until some stopping criteria are met. In the example I focus on conditional inference tree, which incorporates tree-structured regression models into conditional inference procedures. While growing a single tree is subject to small changes in the training data, random forests procedure is introduced to address this problem. The sources of diversity for random forests come from the random sampling and restricted set of input variables to be selected. Finally, I introduce R functions to perform model based recursive partitioning. This method incorporates recursive partitioning into conventional parametric model building. PMID:27570769

    12. Information Commons for Rice (IC4R).

      PubMed

      Hao, Lili; Zhang, Huiyong; Zhang, Zhang; Hu, Songnian; Xue, Yu

      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

    13. 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

    14. rMPI

      Energy Science and Technology Software Center (ESTSC)

      2010-08-24

      As high-performance computing (HPC) machines continue to grow in size, issues such as fault tolerance and reliability limit application scalability. Current techniques to ensure progress across faults, like checkpoint-restart, are unsuitable on their own for exascale machines due to the excessive overheads predicted to more than double an applications time to solution. An alternative mechanism to increase application reliability than just checkpoint-restart alone is redundant computation. The rMPl library enables portable and transparent redundant computation)more » that, at extreme scale, has significantly lower verhead then just checkpoint-restart on its own.« less

    15. 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.

    16. 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

    17. 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.

    18. LuxR solos in Photorhabdus species

      PubMed Central

      Brameyer, Sophie; Kresovic, Darko; Bode, Helge B.; Heermann, Ralf

      2014-01-01

      Bacteria communicate via small diffusible molecules to mediate group-coordinated behavior, a process designated as quorum sensing. The basic molecular quorum sensing system of Gram-negative bacteria consists of a LuxI-type autoinducer synthase producing acyl-homoserine lactones (AHLs) as signaling molecules, and a LuxR-type receptor detecting the AHLs to control expression of specific genes. However, many proteobacteria possess one or more unpaired LuxR-type receptors that lack a cognate LuxI-like synthase, referred to as LuxR solos. The enteric and insect pathogenic bacteria of the genus Photorhabdus harbor an extraordinarily high number of LuxR solos, more than any other known bacteria, and all lack a LuxI-like synthase. Here, we focus on the presence and the different types of LuxR solos in the three known Photorhabdus species using bioinformatics analyses. Generally, the N-terminal signal-binding domain (SBD) of LuxR-type receptors sensing AHLs have a motif of six conserved amino acids that is important for binding and specificity of the signaling molecule. However, this motif is altered in the majority of the Photorhabdus-specific LuxR solos, suggesting the use of other signaling molecules than AHLs. Furthermore, all Photorhabdus species contain at least one LuxR solo with an intact AHL-binding motif, which might allow the ability to sense AHLs of other bacteria. Moreover, all three species have high AHL-degrading activity caused by the presence of different AHL-lactonases and AHL-acylases, revealing a high quorum quenching activity against other bacteria. However, the majority of the other LuxR solos in Photorhabdus have a N-terminal so-called PAS4-domain instead of an AHL-binding domain, containing different amino acid motifs than the AHL-sensors, which potentially allows the recognition of a highly variable range of signaling molecules that can be sensed apart from AHLs. These PAS4-LuxR solos are proposed to be involved in host sensing, and therefore in

    19. R-body-producing bacteria.

      PubMed Central

      Pond, F R; Gibson, I; Lalucat, J; Quackenbush, R L

      1989-01-01

      Until 10 years ago, R bodies were known only as diagnostic features by which endosymbionts of paramecia were identified as kappa particles. They were thought to be limited to the cytoplasm of two species in the Paramecium aurelia species complex. Now, R bodies have been found in free-living bacteria and other Paramecium species. The organisms now known to form R bodies include the cytoplasmic kappa endosymbionts of P. biaurelia and P. tetraurelia, the macronuclear kappa endosymbionts of P. caudatum, Pseudomonas avenae (a free-living plant pathogen), Pseudomonas taeniospiralis (a hydrogen-oxidizing soil microorganism), Rhodospirillum centenum (a photosynthetic bacterium), and a soil bacterium, EPS-5028, which is probably a pseudomonad. R bodies themselves fall into five distinct groups, distinguished by size, the morphology of the R-body ribbons, and the unrolling behavior of wound R bodies. In recent years, the inherent difficulties in studying the organization and assembly of R bodies by the obligate endosymbiont kappa, have been alleviated by cloning and expressing genetic determinants for these R bodies (type 51) in Escherichia coli. Type 51 R-body synthesis requires three low-molecular-mass polypeptides. One of these is modified posttranslationally, giving rise to 12 polypeptide species, which are the major structural subunits of the R body. R bodies are encoded in kappa species by extrachromosomal elements. Type 51 R bodies, produced in Caedibacter taeniospiralis, are encoded by a plasmid, whereas bacteriophage genomes probably control R-body synthesis in other kappa species. However, there is no evidence that either bacteriophages or plasmids are present in P. avenae or P. taeniospiralis. No sequence homology was detected between type 51 R-body-encoding DNA and DNA from any R-body-producing species, except C. varicaedens 1038. The evolutionary relatedness of different types of R bodies remains unknown. Images PMID:2651865

    20. Becoming A/r/tography

      ERIC Educational Resources Information Center

      Irwin, Rita L.

      2013-01-01

      This article explores moments of becoming a/r/tography. A/r/tography is a research methodology, a creative practice, and a performative pedagogy that lives in the rhizomatic practices of the in-between. Resisting the tendency for endless critique of past experience and bodies of knowledge, a/r/tography is concerned with the creative invention of…

    1. 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.

    2. Insilico study of the A(2A)R-D (2)R kinetics and interfacial contact surface for heteromerization.

      PubMed

      Prakash, Amresh; Luthra, Pratibha Mehta

      2012-10-01

      G-protein-coupled receptors (GPCRs) are cell surface receptors. The dynamic property of receptor-receptor interactions in GPCRs modulates the kinetics of G-protein signaling and stability. In the present work, the structural and dynamic study of A(2A)R-D(2)R interactions was carried to acquire the understanding of the A(2A)R-D(2)R receptor activation and deactivation process, facilitating the design of novel drugs and therapeutic target for Parkinson's disease. The structure-based features (Alpha, Beta, SurfAlpha, and SurfBeta; GapIndex, Leakiness and Gap Volume) and slow mode model (ENM) facilitated the prediction of kinetics (K (off), K (on), and K (d)) of A(2A)R-D(2)R interactions. The results demonstrated the correlation coefficient 0.294 for K (d) and K (on) and the correlation coefficient 0.635 for K (d) and K (off), and indicated stable interfacial contacts in the formation of heterodimer. The coulombic interaction involving the C-terminal tails of the A(2A)R and intracellular loops (ICLs) of D(2)R led to the formation of interfacial contacts between A(2A)R-D(2)R. The properties of structural dynamics, ENM and KFC server-based hot-spot analysis illustrated the stoichiometry of A(2A)R-D(2)R contact interfaces as dimer. The propensity of amino acid residues involved in A(2A)R-D(2)R interaction revealed the presence of positively (R, H and K) and negatively (E and D) charged structural motif of TMs and ICL3 of A(2A)R and D(2)R at interface of dimer contact. Essentially, in silico structural and dynamic study of A(2A)R-D(2)R interactions will provide the basic understanding of the A(2A)R-D(2)R interfacial contact surface for activation and deactivation processes, and could be used as constructive model to recognize the protein-protein interactions in receptor assimilations. PMID:22278740

    3. R&D Alert. Volume 7, Number 2, 2005

      ERIC Educational Resources Information Center

      White, Noel, Ed.

      2005-01-01

      "R&D Alert" covers issues affecting schools in the Western Regional Educational Laboratory's four-state region--Arizona, California, Nevada, and Utah--and throughout the United States. This issue of "R&D Alert" shares what WestEd is learning from a sample of their latest work, focusing on three points in the process: preservice, inservice, and…

    4. R.I.C.E.--Four Values for Civic Education.

      ERIC Educational Resources Information Center

      Dondero, Marian; McCoy, Elizabeth

      1996-01-01

      Examines the uses of R.I.C.E. (Responsibility, Interdependence, Creativity, and Empowerment) processes to enhance civic education programs. Highlights R.I.C.E.'s compatibility with the National Standards for Civics and Government in the areas of shared responsibility, global interdependence, dynamic creativity, and people empowerment. Includes…

    5. Possible problems in ENDF/B-VI.r8

      SciTech Connect

      Brown, D; Hedstrom, G

      2003-10-30

      This document lists the problems that we encountered in processing ENDF/B-VI.r8 that we suspect are problems with ENDF/B-VI.r8 itself. It also contains a comparison of linear interpolation methods. Finally, this documents proposes an alternative to the current scheme of reporting problems to the ENDF community.

    6. 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...

    7. 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...

    8. Concise Synthesis of (2R,4R)-Monatin.

      PubMed

      Amino, Yusuke

      2016-01-01

      Monatin, 4-hydroxy-4-(3-indolylmethyl)-glutamic acid, is a naturally occurring sweet amino acid. The (2R,4R)-monatin isomer has been found to be the sweetest among its four stereoisomers. A concise and efficient synthesis of (2R,4R)-monatin was accomplished by the alkylation of (4R)-N-tert-butoxycarbonyl (tBoc)-4-tert-butyldimethylsilyoxy-D-pyroglutamic acid methyl ester with tert-butyl 3-(bromomethyl)-1H-indole-1-carboxylate to give (4R)-N-tBoc-4-tert-butyldimethylsilyloxy-4-(N-tBoc-3-indolylmethyl)-D-pyroglutamic acid methyl ester, i.e., the lactam form of (2R,4R)-monatin with protecting groups. This was followed by the hydrolysis of the lactam ring and deprotection. The 4-hydroxyl D-pyroglutamic acid derivative was demonstrated to be a suitable precursor for the efficient preparation of (2R,4R)-monatin in high optical purity because the alkylation proceeded in regioselective and stereoselective manners at C4 to form appropriate asymmetric tetra-substituted carbon center; the resulting alkylated pyroglutamic acid derivative was then easily converted into the linear form of monatin. PMID:27477667

    9. The quorum sensing negative regulators EsaR and ExpR(Ecc), homologues within the LuxR family, retain the ability to function as activators of transcription.

      PubMed

      von Bodman, Susanne B; Ball, Jessica K; Faini, Marie A; Herrera, Carmen M; Minogue, Timothy D; Urbanowski, Mark L; Stevens, Ann M

      2003-12-01

      Most LuxR homologues function as activators of transcription during the process of quorum sensing, but a few, including EsaR and ExpR(Ecc), negatively impact gene expression. The LuxR-activated luxI promoter and LuxR binding site, the lux box, were used in artificial contexts to assess the potential for transcriptional activation and DNA binding by EsaR and ExpR(Ecc). Although the acyl-homoserine lactone responsiveness of both proteins is the opposite of that shown by most LuxR family members, EsaR and ExpR(Ecc) have preserved the ability to interact with RNA polymerase and activate transcription despite their low affinity for the lux box DNA. PMID:14617666

    10. Lee R. Scherer

      NASA Technical Reports Server (NTRS)

      1980-01-01

      Lee R. Scherer was appointed Director of the NASA Flight Research Center on October 11, 1971, a position he held until January 28, 1975. Mr. Scherer first worked with NASA in 1962 while still on active duty with the U.S. Navy as a Captain. Prior to his arriving at the Flight Research Center he was at NASA Headquarters' Office of Space Science and Applications, as Director of the Apollo Program for the scientific aspects of lunar explorations, Assistant Director of Lunar Programs, and Manager of the Lunar Orbiter Program from its inception in 1963 through its successful completion in 1967. Scherer graduated from the U.S. Naval Academy in 1942. Most of Lee's 25-year Naval career was spent in aviation, including a tour flying carrier-based fighters and flight test experience with helicopters. Prior to entering the Naval Academy, he attended the University of Kentucky for one year. He received a second Bachelor of Science degree in aeronautical engineering in 1949 from the U.S. Naval Postgraduate School and his Master's degree in aeronautical engineering from the California Institute of Technology (Caltech) in 1950. Lee also attended the Summer of Industrial Management Studies program at the University of California at Los Angeles in 1949. Awards he has received include the NASA's Exceptional Service Medal in 1967 and NASA's Exceptional Scientific Achievement Medal in 1969.

    11. Microbial Extracellular Enzyme Activity and Community Assembly Processes Post Fire Disturbance Amanda Labrado, University of Texas at El Paso; Emily B. Graham, University of Colorado Boulder; Joseph E. Knelman, University of Colorado Boulder; Scott Ferrenberg, University of Colorado Boulder; Diana R. Nemergut, University of Colorado Boulder

      NASA Astrophysics Data System (ADS)

      Labrdo, A.; Knelman, J. E.; Graham, E. B.; Ferrenberg, S.; Nemergut, D. R.

      2013-12-01

      Microbes control major biogeochemical cycles and can directly impact the carbon, nitrogen, and phosphorus pools and fluxes of soils. However, many questions remain regarding when and where data on microbial community structure are necessary to accurately predict biogeochemical processes. In particular, it is unknown how shifts in microbial assembly processes may relate to changes in the relationship between community structure and ecosystem function. Here, we examine soil microbial community assembly processes and extracellular enzyme activity (EEA) at 4-weeks and 16-weeks after the Fourmile Canyon Fire in Boulder, CO in order to determine the effects of disturbance on community assembly and EEA. Microbial community structure was determined from 16S rRNA gene pyrosequencing, edaphic properties were determined using standard biogeochemical assays, and extracellular enzyme activity for β-1, 4-glucosidase (BG) and β-1, 4-N-acetylglucosaminidase (NAG) enzymes were determined using fluorimetric assays. Stepwise linear regressions were used to determine the effects of microbial community structure and edaphic factors on EEA. We determined that in 4-week post fire samples EEA was only correlated with microbial predictors. However, we observed a shift with 16-week samples in which EEA was significantly related to edaphic predictors. Null derivation analysis of community assembly revealed that communities in the 4-week samples were more neutrally assembled than communities in the 16-week samples. Together, these results support a conceptual model in which the relationship between edaphic factors and ecosystem processes is somewhat decoupled in more neutrally assembled communities, and data on microbial community structure is important to most accurately predict function.

    12. Upregulation of miR-150* and miR-630 Induces Apoptosis in Pancreatic Cancer Cells by Targeting IGF-1R

      PubMed Central

      Farhana, Lulu; Dawson, Marcia I.; Murshed, Farhan; Das, Jayanta K.; Rishi, Arun K.; Fontana, Joseph A.

      2013-01-01

      MicroRNAs have been implicated in many critical cellular processes including apoptosis. We have previously found that apoptosis in pancreatic cancer cells was induced by adamantyl retinoid-related (ARR) molecule 3-Cl-AHPC. Here we report that 3-Cl-AHPC-dependent apoptosis involves regulating a number of microRNAs including miR-150* and miR-630. 3-Cl-AHPC stimulated miR-150* expression and caused decreased expression of c-Myb and IGF-1R in the pancreatic cancer cells. 3-Cl-AHPC-mediated reduction of c-Myb resulted in diminished binding of c-Myb with IGF-1R and Bcl-2 promoters, thereby causing repression of their transcription and protein expression. Over-expression of miR-150* also resulted in diminished levels of c-Myb and Bcl-2 proteins. Furthermore, the addition of the miRNA inhibitor 2′-O-methylated miR-150 blocked 3-Cl-AHPC-mediated increase in miR-150* levels and abrogated loss of c-Myb protein. Knockdown of c-Myb in PANC-1 cells resulted in enhanced apoptosis both in the presence or absence of 3-Cl-AHPC confirming the anti-apoptotic property of c-Myb. Overexpression of miR-630 also induced apoptosis in the pancreatic cancer cells and inhibited target protein IGF-1R mRNA and protein expression. Together these results implicate key roles for miR-150* and miR-630 and their targeting of IGF-1R to promote apoptosis in pancreatic cancer cells. PMID:23675407

    13. Extending the R-2R lens to 360 deg

      NASA Astrophysics Data System (ADS)

      Clapp, R. E.

      1984-07-01

      The R-2R lens is a remarkable microwave device that provides perfect focusing, giving multiple simultaneous antenna beams from a circular or cylindrical array. However, the perfect focusing of the R-2R brings with it a serious limitation on angular coverage as a result of the angular doubling that enters when the array elements in the antenna are connected to the launcher elements on the lens periphery. A way has now been found to modify the R-2R concept so that a full circle of array elements can be mapped onto a full circle of beam ports. The new mapping makes use of hybrid junctions and either four or six physical lenses. The interconnections result in 360 deg of simultaneous antenna beams, each of which can be used both for transmission and for reception.

    14. 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.

    15. Calcium binding decreases the stokes radius of calmodulin and mutants R74A, R90A, and R90G.

      PubMed Central

      Sorensen, B R; Shea, M A

      1996-01-01

      Calmodulin (CaM) is an intracellular cooperative calcium-binding protein essential for activating many diverse target proteins. Biophysical studies of the calcium-induced conformational changes of CaM disagree on the structure of the linker between domains and possible orientations of the domains. Molecular dynamics studies have predicted that Ca4(2+)CaM is in equilibrium between an extended and compact conformation and that Arg74 and Arg90 are critical to the compaction process. In this study gel permeation chromatography was used to resolve calcium-induced changes in the hydrated shape of CaM at pH 7.4 and 5.6. Results showed that mutation of Arg 74 to Ala increases the R(s) as predicted; however, the average separation of domains in Ca4(2+)-CaM was larger than predicted by molecular dynamics. Mutation of Arg90 to Ala or Gly affected the dimensions of apo-CaM more than those of Ca4(2+)-CaM. Calcium binding to CaM and mutants (R74A-CaM, R90A-CaM, and R90G-CaM) lowered the Stokes radius (R(s)). Differences between R(s) values reported here and Rg values determined by small-angle x-ray scattering studies illustrate the importance of using multiple techniques to explore the solution properties of a flexible protein such as CaM. Images FIGURE 2 SCHEME 1 FIGURE 3 PMID:8968610

    16. Adsorption of poly(rA) on the carbon nanotube surface and its hybridization with poly(rU).

      PubMed

      Karachevtsev, Victor A; Gladchenko, Galyna O; Karachevtsev, Maksym V; Valeev, Vladimir A; Leontiev, Victor S; Lytvyn, Oksana S

      2008-10-01

      Adsorption of poly(rA) on a single-walled carbon nanotube surface in aqueous suspension and the subsequent hybridization of this polymer with free poly(rU) is studied. A comparison of the temperature dependence of the absorbance of free poly(rA) and poly(rA) adsorbed on the nanotube surface [poly(rA)(NT)] at nu(max)= 38,500 cm(-1) shows that the thermostability of the adsorbed polymer is higher. Molecular dynamics simulations demonstrate that more than half of the adenines are not stacked on the tube surface and some of them undergo self-stacking. After addition of a complementary poly(rU) to the poly(rA)(NT) suspension, a double-stranded polymer is formed as confirmed by the characteristic S-like form of its melting curve. However, the melting temperature of this polymer is lower than that of the free poly(rA)poly(rU) duplex. This result indicates that poly(rU) hybridization with poly(rA)(NT) occurs with defects along the whole length of the polymer because of pi-pi stacking between nitrogen bases and the nanotube surface, which hinders the usual hybridization process. Computer modeling demonstrates different possible structures of hybridized polymers on the nanotube surface. PMID:18780410

    17. Craig R. Bomben

      NASA Technical Reports Server (NTRS)

      2001-01-01

      Craig R. Bomben became a pilot in the Flight Crew Branch of NASA's Dryden Flight Research Center, Edwards, Calif., in June 2001. His flying duties include a variety of research and support activities while piloting the F/A-18, DC-8, T-34C and King Air aircraft. He has more than 17 years and 3,800 hours of military and civilian flight experience in over 50 different aircraft types. Bomben came to NASA Dryden from a U.S. Navy assignment to the Personnel Exchange Program, Canada. He served as a test pilot in the Canadian Armed Forces located in Cold Lake, Alberta. He participated in numerous developmental programs to include CT-133 airborne ejection seat testing, F/A-18 weapons flutter testing and F/A-18 night vision goggles integration. Bomben performed U.S. Navy fleet service in 1995 as a strike-fighter department head. He completed two overseas deployments onboard the USS George Washington and USS Stennis. As a combat strike leader, he headed numerous multi-national missions over Iraq in support of Operation Southern Watch. Bomben graduated from the U.S. Naval Test Pilot School in 1992 and was subsequently assigned to the Naval Weapons Test Squadron at Pt. Mugu, Calif. During this tour he developed the F-14D bombsight and worked on various other F-14D and F/A-18 weapon systems developmental programs. Bomben is a 1985 graduate of Washington State University with a bachelor of science degree in electrical engineering. He graduated from naval flight training in 1987 and was recognized as a Commodore List graduate. His first assignment was to Naval Air Station Pensacola, Fla., where he was an instructor in the T-2B Buckeye. When selected to fly the F/A-18 in 1989, he joined a fleet squadron and deployed aboard the USS Forrestal. Bomben is married to the former Aissa Asuncion. They live in Lancaster, Calif., with their 3 children.

    18. Rosen's (M,R) system in Unified Modelling Language.

      PubMed

      Zhang, Ling; Williams, Richard A; Gatherer, Derek

      2016-01-01

      Robert Rosen's (M,R) system is an abstract biological network architecture that is allegedly non-computable on a Turing machine. If (M,R) is truly non-computable, there are serious implications for the modelling of large biological networks in computer software. A body of work has now accumulated addressing Rosen's claim concerning (M,R) by attempting to instantiate it in various software systems. However, a conclusive refutation has remained elusive, principally since none of the attempts to date have unambiguously avoided the critique that they have altered the properties of (M,R) in the coding process, producing merely approximate simulations of (M,R) rather than true computational models. In this paper, we use the Unified Modelling Language (UML), a diagrammatic notation standard, to express (M,R) as a system of objects having attributes, functions and relations. We believe that this instantiates (M,R) in such a way than none of the original properties of the system are corrupted in the process. Crucially, we demonstrate that (M,R) as classically represented in the relational biology literature is implicitly a UML communication diagram. Furthermore, since UML is formally compatible with object-oriented computing languages, instantiation of (M,R) in UML strongly implies its computability in object-oriented coding languages. PMID:26723228

    19. Unraveling the regulatory network in Streptococcus pyogenes: the global response regulator CovR represses rivR directly.

      PubMed

      Roberts, Samantha A; Churchward, Gordon G; Scott, June R

      2007-02-01

      The response regulator CovR acts as a master regulator of virulence in Streptococcus pyogenes by repressing transcription of approximately 15% of the group A streptococcus genome directly or indirectly. We demonstrate that phosphorylated CovR represses transcription of rivR directly by binding to conserved sequences located downstream from the promoter to block procession of RNA polymerase. This establishes the first link in a regulatory network where CovR interacts directly with other proteins that modulate gene expression. PMID:16963575

    20. R & D Employment in the U.S.S.R.

      ERIC Educational Resources Information Center

      Nolting, Louvan E.; Feshbach, Murray

      1980-01-01

      Examined are the number and distribution of persons engaged in research and development in the U.S.S.R. Quantitative comparisons are made between Soviet and U.S. research and development employment. Data indicate that the estimated number of scientists and engineers in the U.S.S.R. substantially exceeds the number in the U.S. (Author/CS)

    1. "catR": An R Package for Computerized Adaptive Testing

      ERIC Educational Resources Information Center

      Magis, David; Raiche, Gilles

      2011-01-01

      Computerized adaptive testing (CAT) is an active current research field in psychometrics and educational measurement. However, there is very little software available to handle such adaptive tasks. The R package "catR" was developed to perform adaptive testing with as much flexibility as possible, in an attempt to provide a developmental and…

    2. POSSIBLE ORIGIN OF RHIC R OUT / R SID HBT RESULTS.

      SciTech Connect

      PADULA,S.

      2002-07-18

      The effects of opacity of the nuclei together with a blackbody type of emission along the system history are considered as a means to explain the ratio R{sub out}/R{sub sid} observed by STAR and PHENIX collaborations at RHIC. Within our model, no flow is required to explain the data trend of this ratio for large surface emissivities.

    3. Antiausterity activity of arctigenin enantiomers: importance of (2R,3R)-absolute configuration.

      PubMed

      Awale, Suresh; Kato, Mamoru; Dibwe, Dya Fita; Li, Feng; Miyoshi, Chika; Esumi, Hiroyasu; Kadota, Shigetoshi; Tezuka, Yasuhiro

      2014-01-01

      From a MeOH extract of powdered roots of Wikstroemia indica, six dibenzyl-gamma-butyrolactone-type lignans with (2S,3S)-absolute configuration [(+)-arctigenin (1), (+)-matairesinol (2), (+)-trachelogenin (3), (+)-nortrachelogenin (4), (+)-hinokinin (5), and (+)-kusunokinin (6)] were isolated, whereas three dibenzyl-gamma-butyrolactone-type lignans with (2R,3R)-absolute configuration [(-)-arctigenin (1*), (-)-matairesinol (2*), (-)-trachelogenin (3*)] were isolated from Trachelospermum asiaticum. The in vitro preferential cytotoxic activity of the nine compounds was evaluated against human pancreatic PANC-1 cancer cells in nutrient-deprived medium (NDM), but none of the six lignans (1-6) with (2S,3S)-absolute configuration showed preferential cytotoxicity. On the other hand, three lignans (1*-3*) with (2R,3R)-absolute configuration exhibited preferential cytotoxicity in a concentration-dependent manner with PC50 values of 0.54, 6.82, and 5.85 microM, respectively. Furthermore, the effect of (-)- and (+)-arctigenin was evaluated against the activation of Akt, which is a key process in the tolerance to nutrition starvation. Interestingly, only (-)-arctigenin (1*) strongly suppressed the activation of Akt. These results indicate that the (2R,3R)-absolute configuration of (-)-enantiomers should be required for the preferential cytotoxicity through the inhibition of Akt activation. PMID:24660468

    4. 22(R)-hydroxycholesterol induces HuR-dependent MAP kinase phosphatase-1 expression via mGluR5-mediated Ca(2+)/PKCα signaling.

      PubMed

      Kim, Hyunmi; Woo, Joo Hong; Lee, Jee Hoon; Joe, Eun-Hye; Jou, Ilo

      2016-08-01

      MAP kinase phosphatase (MKP)-1 plays a pivotal role in controlling MAP kinase (MAPK)-dependent (patho) physiological processes. Although MKP-1 gene expression is tightly regulated at multiple levels, the underlying mechanistic details remain largely unknown. In this study, we demonstrate that MKP-1 expression is regulated at the post-transcriptional level by 22(R)-hydroxycholesterol [22(R)-HC] through a novel mechanism. 22(R)-HC induces Hu antigen R (HuR) phosphorylation, cytoplasmic translocation and binding to MKP-1 mRNA, resulting in stabilization of MKP-1 mRNA. The resulting increase in MKP-1 leads to suppression of JNK-mediated inflammatory responses in brain astrocytes. We further demonstrate that 22(R)-HC-induced phosphorylation of nuclear HuR is mediated by PKCα, which is activated in the cytosol by increases in intracellular Ca(2+) levels mediated by the phospholipase C/inositol 1,4,5-triphosphate receptor (PLC/IP3R) pathway and translocates from cytoplasm to nucleus. In addition, pharmacological interventions reveal that metabotropic glutamate receptor5 (mGluR5) is responsible for the increases in intracellular Ca(2+) that underlie these actions of 22(R)-HC. Collectively, our findings identify a novel anti-inflammatory mechanism of 22(R)-HC, which acts through PKCα-mediated cytoplasmic shuttling of HuR to post-transcriptionally regulate MKP-1 expression. These findings provide an experimental basis for the development of a RNA-targeted therapeutic agent to control MAPK-dependent inflammatory responses. PMID:27206966

    5. DendrometeR: analyzing the pulse of trees in R

      NASA Astrophysics Data System (ADS)

      van der Maaten, Ernst; van der Maaten-Theunissen, Marieke; Smiljanic, Marko; Rossi, Sergio; Simard, Sonia; Deslauriers, Annie; Wilmking, Martin; Bouriaud, Olivier

      2016-04-01

      We present an R package named dendrometeR to analyze "the pulse of trees": stem cycles recorded by high-resolution dendrometers. The package dendrometeR facilitates data preparation (i.e. importing and gap filling) as well as the analysis of dendrometer series using a stem-cycle approach. In this approach, dendrometer series are separated into cyclic phases of contraction, expansion and stem radius increment in order to extract information on tree water-use and xylem growth. A segmentation function developed for environmental datasets, that calculates statistics for the respective phases and cycles (e.g. mean temperature or precipitation sums), allows to assess the meteorological forcing of stem-size variations. The functionality of the package is illustrated on dendrometer data from Canada and Germany. All functions of dendrometeR are designed with entry-level users of R in mind, and come with extensive help pages.

    6. Participation of miR-200 in Pulmonary Fibrosis

      PubMed Central

      Yang, Shanzhong; Banerjee, Sami; de Freitas, Andressa; Sanders, Yan Y.; Ding, Qiang; Matalon, Sadis; Thannickal, Victor J.; Abraham, Edward; Liu, Gang

      2012-01-01

      Excessive extracellular matrix production by fibroblasts in response to tissue injury contributes to fibrotic diseases, such as idiopathic pulmonary fibrosis (IPF). Epithelial-mesenchymal transition, involving transition of alveolar epithelial cells (AECs) to pulmonary fibroblasts, appears to be an important contributory process to lung fibrosis. Although aberrant expression of microRNAs (miRs) is involved in a variety of pathophysiologic processes, the role of miRs in fibrotic lung diseases is less well understood. In the present study, we found that miR-200a, miR-200b, and miR-200c are significantly down-regulated in the lungs of mice with experimental lung fibrosis. Levels of miR-200a and miR-200c were reduced in the lungs of patients with IPF. miR-200 had greater expression in AECs than in lung fibroblasts, and AECs from mice with experimental pulmonary fibrosis had diminished expression of miR-200. We found that the miR-200 family members inhibit transforming growth factor-β1–induced epithelial-mesenchymal transition of AECs. miR-200 family members can reverse the fibrogenic activity of pulmonary fibroblasts from mice with experimental pulmonary fibrosis and from patients with IPF. Indeed, the introduction of miR-200c diminishes experimental pulmonary fibrosis in mice. Thus, the miR-200 family members participate importantly in fibrotic lung diseases and suggest that restoring miR-200 expression in the lungs may represent a novel therapeutic approach in treating pulmonary fibrotic diseases. PMID:22189082

    7. R/V Maurice Ewing retires

      NASA Astrophysics Data System (ADS)

      Diebold, John

      2005-07-01

      The R/V Maurice Ewing came into port for the last time on 10 March 2005, tying up at Quonset Point, R.I., astern of the ship slated to be her replacement (Figure 1). M/V Western Legend (Figure 1, left) will, during fall and winter of 2005-2006, be converted as R/V Marcus G. Langseth, and will replace the Maurice Ewing (Figure 1, right) as the primary seismic research vessel within the U.S. academic research vessel fleet.During its distinguished 15-year career, Ewing's operations added fundamentally to the knowledge and understanding of solid Earth dynamics and structure. Ewing began life as the M/V Bernier, and performed seismic offshore exploration for Petro Canada. In an innovative process, which included initialization provided by Columbia University, the U.S. National Science Foundation (NSF) acquired Bernier in 1989, and the ship's title passed to NSF in 1990. Bernier was converted into R/V Ewing for a total expenditure (approximately $12 million) far below the cost of building and outfitting a new seismic research ship.

    8. Process for functionalizing alkanes

      DOEpatents

      Bergman, Robert G.; Janowicz, Andrew H.; Periana, Roy A.

      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.

    9. Oklahoma NASA EPSCoR

      NASA Technical Reports Server (NTRS)

      Snowden, Victoria Duca

      2002-01-01

      The mission of Oklahoma EPSCoR is to make Oklahoma researchers more successful in competing for research funding. Specific goals, objectives, and strategies were developed for each federal EPSCoR program, based on federal and state needs. A theme of stimulating collaboration among campuses and building on common research strengths is a strong component of the Oklahoma EPSCoR strategic plan. It extends also to our relationships with the federal agencies, and wherever possible, Oklahoma EPSCoR projects are developed collaboratively with federal research laboratories and program offices. Overall, Oklahoma EPSCoR seeks to capitalize on unique research capabilities and opportunities. The NASA EPSCoR Program in Oklahoma was developed through this grant as a joint effort between Oklahoma EPSCoR and the NASA Oklahoma Space Grant Consortium (OSGC). The major goal of the Oklahoma NASA EPSCoR Plan established in 1996 is to develop an academic research enterprise directed towards a long-term, self-sustaining, nationally competitive capability in areas of mutual self-interest to NASA and Oklahoma. Our final technical summary pie chart demonstrates the strong successes we have achieved during this period as a result of the award.

    10. Investigation on the boiling heat transfer characteristics of R404A and R134a under stratified flow condition

      NASA Astrophysics Data System (ADS)

      Balachander, P.; Raja, B.

      2015-06-01

      An experimental investigation on the flow boiling heat transfer characteristics of R404A and R134a for low mass flux and heat flux conditions in a smooth horizontal tube is reported. Refrigerant saturation temperatures -15, -10, -5 and 0 °C were considered for the flow boiling conditions. The influence of the mass flux, heat flux and saturation temperature on the heat transfer coefficients of R404A and R134a are discussed in detail. The predominant flow pattern for the tested conditions is confirmed to be the stratified-wavy flow. The study revealed that the heat transfer coefficient is a strong function of the heat flux, throughout the flow boiling process, and the nucleate boiling contribution is much higher for R404A compared to that of R134a. The heat transfer characteristic of R404A is compared with that of R134a, to understand their relative performance in low temperature appliances. A modified correlation for the flow boiling heat transfer coefficient of R404A is developed to fit the experimental results of R404A.

    11. Genome-Wide Identification of R2R3-MYB Genes and Expression Analyses During Abiotic Stress in Gossypium raimondii

      PubMed Central

      He, Qiuling; Jones, Don C.; Li, Wei; Xie, Fuliang; Ma, Jun; Sun, Runrun; Wang, Qinglian; Zhu, Shuijin; Zhang, Baohong

      2016-01-01

      The R2R3-MYB is one of the largest families of transcription factors, which have been implicated in multiple biological processes. There is great diversity in the number of R2R3-MYB genes in different plants. However, there is no report on genome-wide characterization of this gene family in cotton. In the present study, a total of 205 putative R2R3-MYB genes were identified in cotton D genome (Gossypium raimondii), that are much larger than that found in other cash crops with fully sequenced genomes. These GrMYBs were classified into 13 groups with the R2R3-MYB genes from Arabidopsis and rice. The amino acid motifs and phylogenetic tree were predicted and analyzed. The sequences of GrMYBs were distributed across 13 chromosomes at various densities. The results showed that the expansion of the G. Raimondii R2R3-MYB family was mainly attributable to whole genome duplication and segmental duplication. Moreover, the expression pattern of 52 selected GrMYBs and 46 GaMYBs were tested in roots and leaves under different abiotic stress conditions. The results revealed that the MYB genes in cotton were differentially expressed under salt and drought stress treatment. Our results will be useful for determining the precise role of the MYB genes during stress responses with crop improvement. PMID:27009386

    12. Implementing spatial segregation measures in R.

      PubMed

      Hong, Seong-Yun; O'Sullivan, David; Sadahiro, Yukio

      2014-01-01

      Reliable and accurate estimation of residential segregation between population groups is important for understanding the extent of social cohesion and integration in our society. Although there have been considerable methodological advances in the measurement of segregation over the last several decades, the recently developed measures have not been widely used in the literature, in part due to their complex calculation. To address this problem, we have implemented several newly proposed segregation indices in R, an open source software environment for statistical computing and graphics, as a package called seg. Although there are already a few standalone applications and add-on packages that provide access to similar methods, our implementation has a number of advantages over the existing tools. First, our implementation is flexible in the sense that it provides detailed control over the calculation process with a wide range of input parameters. Most of the parameters have carefully chosen defaults, which perform acceptably in many situations, so less experienced users can also use the implemented functions without too much difficulty. Second, there is no need to export results to other software programs for further analysis. We provide coercion methods that enable the transformation of our output classes into general R classes, so the user can use thousands of standard and modern statistical techniques, which are already available in R, for the post-processing of the results. Third, our implementation does not require commercial software to operate, so it is accessible to a wider group of people. PMID:25415326

    13. Hydrocarbon Processing`s gas processes `96

      SciTech Connect

      1996-04-01

      This review summarizes 71 processes, describing the process, its application, products, operating conditions, economics, installations, and licensor. Processes include desulfurization, CO{sub 2} removal, sulfur recovery, NGL recovery, deoxygenation, hydrogen production and separation, cryogenic separation of hydrocarbon fractions, dehydration, liquefaction of natural gas, LPG recovery, denitrogenation, and synthesis gas production. While most processes apply to natural gas, some are also useful for refinery gas, synthesis gas, coal mine gas, and tail gas from other processes.

    14. miR-221 overexpression contributes to liver tumorigenesis.

      PubMed

      Pineau, Pascal; Volinia, Stefano; McJunkin, Katherine; Marchio, Agnès; Battiston, Carlo; Terris, Benoît; Mazzaferro, Vincenzo; Lowe, Scott W; Croce, Carlo M; Dejean, Anne

      2010-01-01

      MicroRNA (miRNAs) are negative regulators of gene expression and can function as tumor suppressors or oncogenes. Expression patterns of miRNAs and their role in the pathogenesis of hepatocellular carcinoma (HCC) are still poorly understood. We profiled miRNA expression in tissue samples (104 HCC, 90 adjacent cirrhotic livers, 21 normal livers) as well as in 35 HCC cell lines. A set of 12 miRNAs (including miR-21, miR-221/222, miR-34a, miR-519a, miR-93, miR-96, and let-7c) was linked to disease progression from normal liver through cirrhosis to full-blown HCC. miR-221/222, the most up-regulated miRNAs in tumor samples, are shown to target the CDK inhibitor p27 and to enhance cell growth in vitro. Conversely, these activities can be efficiently inhibited by an antagomiR specific for miR-221. In addition, we show, using a mouse model of liver cancer, that miR-221 overexpression stimulates growth of tumorigenic murine hepatic progenitor cells. Finally, we identified DNA damage-inducible transcript 4 (DDIT4), a modulator of mTOR pathway, as a bona fide target of miR-221. Taken together, these data reveal an important contribution for miR-221 in hepatocarcinogenesis and suggest a role for DDIT4 dysregulation in this process. Thus, the use of synthetic inhibitors of miR-221 may prove to be a promising approach to liver cancer treatment. PMID:20018759

    15. miR-221 overexpression contributes to liver tumorigenesis

      PubMed Central

      Pineau, Pascal; Volinia, Stefano; McJunkin, Katherine; Marchio, Agnès; Battiston, Carlo; Terris, Benoît; Mazzaferro, Vincenzo; Lowe, Scott W.; Croce, Carlo M.; Dejean, Anne

      2009-01-01

      MicroRNA (miRNAs) are negative regulators of gene expression and can function as tumor suppressors or oncogenes. Expression patterns of miRNAs and their role in the pathogenesis of hepatocellular carcinoma (HCC) are still poorly understood. We profiled miRNA expression in tissue samples (104 HCC, 90 adjacent cirrhotic livers, 21 normal livers) as well as in 35 HCC cell lines. A set of 12 miRNAs (including miR-21, miR-221/222, miR-34a, miR-519a, miR-93, miR-96, and let-7c) was linked to disease progression from normal liver through cirrhosis to full-blown HCC. miR-221/222, the most up-regulated miRNAs in tumor samples, are shown to target the CDK inhibitor p27 and to enhance cell growth in vitro. Conversely, these activities can be efficiently inhibited by an antagomiR specific for miR-221. In addition, we show, using a mouse model of liver cancer, that miR-221 overexpression stimulates growth of tumorigenic murine hepatic progenitor cells. Finally, we identified DNA damage-inducible transcript 4 (DDIT4), a modulator of mTOR pathway, as a bona fide target of miR-221. Taken together, these data reveal an important contribution for miR-221 in hepatocarcinogenesis and suggest a role for DDIT4 dysregulation in this process. Thus, the use of synthetic inhibitors of miR-221 may prove to be a promising approach to liver cancer treatment. PMID:20018759

    16. 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...

    17. 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.

    18. 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. Experimental results

      SciTech Connect

      Sharov, V. I. Morozov, A. A.; Shindin, R. A.; Antonenko, V. G.; Borzakov, S. B.; Borzunov, Yu. T.; Chernykh, E. V.; Chumakov, V. F.; Dolgii, S. A.; Finger, M.; Finger, M.; Golovanov, L. B.; Guriev, D. K.; Janata, A.; Kirillov, A. D.; Kovalenko, A. D.; Krasnov, V. A.; Kuzmin, N. A.; Kurilkin, A. K.; Kurilkin, P. K.

      2009-06-15

      New experimental results on ratio R{sub dp} of the quasielastic charge-exchange yield at the outgoing proton angle {theta}{sub p,lab} = 0 deg. for the nd {yields} p(nn) reaction to the elastic np {yields} pn charge-exchange yield, are 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. The intense neutron beam with small momentum spread was produced by breakup of deuterons which were accelerated and extracted to the experimental hall. In both reactions mentioned above the outgoing protons with the momenta p{sub p} approximately equal to the neutron-beam momentum p{sub n,beam} were detected in the directions close to the direction of incident neutrons, i.e., in the vicinity of the scattering angle {theta}{sub p,lab} = 0 deg. Measured in the same data-taking runs, the angular distributions of the charge-exchange-reaction products were corrected for the well-known instrumental effects and averaged in the vicinity of the incident-neutron-beam direction. These corrected angular distributions for every of nd {yields} p(nn) and np {yields} pn charge-exchange processes were proportional to the differential cross sections of the corresponding reactions. The data were accumulated by Delta-Sigma setup magnetic spectrometer with two sets of multiwire proportional chambers located upstream and downstream of the momentum analyzing magnet. Inelastic processes were considerably reduced by the additional detectors surrounding the hydrogen and deuterium targets. The time-of-flight system was applied to identify the detected particles. The accumulated data treatment and analysis, as well as possible sources of the systematic errors are discussed.

    19. Academic R&D Shows Moderate Growth.

      ERIC Educational Resources Information Center

      Chemical and Engineering News, 1982

      1982-01-01

      Data are presented on university research and development (R&D) focusing on character and fields of university R&D sources of funds, federally financed R&D spending, top 12 universities in R&D spending and top 12 R&D centers, academic scientists/engineers, chemical degrees, graduate science students, and schools spending most on chemical R&D. (JN)

    20. Optimization of R-(+)-alpha-terpineol production by the biotransformation of R-(+)-limonene.

      PubMed

      Bicas, Juliano Lemos; Barros, Francisco Fábio Cavalcante; Wagner, Roger; Godoy, Helena Teixeira; Pastore, Gláucia Maria

      2008-09-01

      R-(+)-limonene is an abundant and non-expensive by-product of the citrus industry and is, therefore, a suitable starting material for the production of natural flavor and fragrance compounds. The biotransformation of R-(+)-limonene to R-(+)-alpha-terpineol by Fusarium oxysporum 152b has already been reported, although the influence of the main process parameters on the production has not yet been evaluated. In this paper, a Plackett-Burman screening design was used to define the effects of the medium composition (glucose, peptone, yeast extract, malt extract and pH), the presence of a co-substrate (biosurfactant), the cultivation conditions (temperature, agitation), the substrate concentration and the inoculum/culture medium ratio on the absolute amount of R-(+)-alpha-terpineol resulting from this biotransformation. The process conditions were further optimized applying response surface methodology (RSM). The volatiles were extracted using a SPME device and were subsequently quantified by GC-FID and identified by GC-MS. The best results were obtained using 0.5% (v/m) R-(+)-limonene in pure distilled water as the culture medium with an inoculum/culture medium ratio of 0.25 (m/m) and 72 h cultivation at 26 degrees C/240 rpm. Under these conditions the concentration of R-(+)-alpha-terpineol in the culture medium reached 2.4 g L(-1), a production almost six times greater than in earlier trials. The presence of a biosurfactant (0-500 mg L(-1)) did not significantly increase the yield. PMID:18560915