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1

Physical conditions for the r-process  

SciTech Connect

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.

Wanajo, S.; Tachibana, T.; Goriely, S. [Technische Universitaet Muenchen, Excellence Cluster Universe, Boltzmannstr. 2, D-85748 Garching and Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Senior High School of Waseda University, Nerima, Tokyo 177-0044 (Japan); Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, C.P. 226, B-1050 Brussels (Belgium)

2012-11-12

2

Cold r-Process in Supernovae  

SciTech Connect

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

Wanajo, Shinya [Department of Astronomy, School of Science, University of Tokyo, Bunkyo-ku, Tokyo, 113-8654 (Japan)

2008-05-21

3

The r-, p-, and ?p-Process  

NASA Astrophysics Data System (ADS)

The processes discussed in this review are three of the four nucleosynthesis processes involved in producing heavy nuclei beyond Fe (not counting the rp-process in X-ray bursts). Opposite to the fourth process (the s-process), which operates in stellar evolution during He- and C-burning, they are all related to explosive burning phases, (presumably) linked to core collapse supernova events of massive stars. The (classical) p-process is identified with explosive Ne/O-burning in outer zones of the progenitor star. It is intitiated by the passage of the supernova shock wave and acts via photodisintegration reactions like a spallation process which produces neighboring (proton-rich) isotopes from pre-existing heavy nuclei. The reproduction of some of the so-called lighter p-isotopes with A < 100 faces problems in this environment. The only recently discovered ?p-process is related to the innermost ejecta, the neutrino wind expelled from the hot proto-neutron star after core collapse in the supernova explosion. This neutrino wind is proton-rich in its early phase and reactions with neutrinos permit to overcome decay/reaction bottlenecks for the flow beyond the Fe-group, thus permitting the production of those p-isotopes, which face problems in the classical p-process scenario. The understanding of the r-process, being identified for a long time with rapid neutron captures - and passing through nuclei far from stability - is still experiencing major problems. These are on the one hand related to nuclear uncertainties far from stability (masses and half-lives), affecting the process speed and abundance peaks, on the other hand the site is still not definitely located, yet. Later neutron-rich, high entropy phases of the neutrino wind could permit its operation, other options include the ejection of very neutron-rich neutron star matter. Two different environments are required for a weak and a main/strong r-process, witnessed by observations of low metallicity stars.

Thielemann, F.-K.; Dillmann, I.; Farouqi, K.; Fischer, T.; Fröhlich, C.; Kelic-Heil, A.; Korneev, I.; Kratz, K.-L.; Langanke, K.; Liebendörfer, M.; Panov, I. V.; Martinez-Pinedo, G.; Rauscher, T.

2010-01-01

4

The alpha -Process and the r-Process  

NASA Astrophysics Data System (ADS)

If material initially in nuclear statistical equilibrium (NSE) at high temperature and containing a large fraction of alpha -particles (or nucleons) is expanded and cooled so rapidly that not all the alpha -particles have time to reassemble, its final composition will differ substantially from what is traditionally calculated for particle-deficient freeze-outs. It has long been known that this phenomenon, the ``alpha -rich freeze-out," can lead to the production of elements heavier than the iron group, but only up to about zinc (A ~ 66). Here we explore the alpha -rich freeze-out for values of neutron excess larger than previously treated and discover nuclear systematics that, for neutron excesses greater than about 0.05, allow the creation of heavier elements all the way up to A ~ 100, even when most of the ejecta is in the form of heavy elements. In the limit of a very large fraction of unassembled alpha -particles and a large neutron excess, the alpha -rich freeze-out merges smoothly into the classical r-process. In contrast to previous studies, we find that a large part of the nuclear flow in the r-process may be carried by charged particle reactions up to about A = 100. We speculate that the site of these processes is the high entropy ``wind'' of a young (age 1-10 s) neutron star in which neutrino energy deposition is driving mass loss. The appropriate conditions exist in the delayed supernova explosion mechanism of Mayle & Wilson, but they may occur in other models as well. The mass of r-process ejected per supernova is expected to be ~ 10(-4) M\\sun \\ per Type II or Type Ib supernova, but this will be sensitive to details of the presupernova structure, the explosion mechanism, and the amount of material that falls back onto the neutron star when the reverse shock arrives there.

Woosley, S. E.; Hoffman, R. D.

1992-12-01

5

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

NASA Astrophysics Data System (ADS)

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 .

Qian, Yong-Zhong

2003-10-01

6

Fission properties for r-process nuclei  

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

7

Freezeout and Neutrinos in R-Process Nucleosynthesis  

NASA Astrophysics Data System (ADS)

The r process is the rapid neutron capture nucleosynthesis process responsible for the formation of approximately half of the elements with A > 70. While the main characteristics of the r-process are understood, the astrophysical site where it occurs has yet to be pinned down. Here several aspects of the r-process are investigated with the aim of restricting further the conditions necessary for a successful r process. The rare earth peak, a previously poorly understood feature in the r-process abundance distribution, is studied and is found to form as the very neutron-rich r-process products decay to stability. This understanding helps to constrain the conditions under which the r process freezes out. Further constraints are found by investigating the role of neutrinos in the r process. Neutrino-nucleus interaction rates are calculated for select unstable neutron-rich nuclei and are found to be significantly larger than previous estimates. The influence of these rates on the r process strictly limits the neutrino flux that can be present during a successful r process.

Surman, Rebecca Ann

8

THE RARE EARTH PEAK: AN OVERLOOKED r-PROCESS DIAGNOSTIC  

SciTech Connect

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.

Mumpower, Matthew R.; McLaughlin, G. C. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Surman, Rebecca, E-mail: mrmumpow@ncsu.edu, E-mail: gail_mclaughlin@ncsu.edu, E-mail: surmanr@union.edu [Department of Physics and Astronomy, Union College, Schenectady, NY 12308 (United States)

2012-06-20

9

Magmatic Processes (Paper 6R0769)  

NASA Astrophysics Data System (ADS)

The dream of having physics and chemistry contribute equally in unraveling magmatic processes has nearly come true. A rigorous, logical infrastructure of forceful, quantitative investigation has not yet fully emerged, but most all the bits and pieces are hovering about, fidgeting for their rightful places. This quadreinnium is marked by the general quantitative investigation of well defined magmatic process as opposed to construction of detailed physicochemical sceneries to explain specific field problems, although some of this has also produced good results. The surest sign of significant progress is the steady implementation of newly investigated physical processes into petrologic thinking. Regardless of inclination, petrologists are actively seeking evidence for or against various processes, are learning the essentials of the mechanics, and, perhaps best of all, are (most often) accurately using the new vocabulary. We are in the midst of an extremely fertile burst of activity, and the next four years promise, in terms of quantitatively solving problems, to be even better.

Marsh, Bruce

1987-06-01

10

Precise Mass Measurements of Nuclides Approaching the R-Process  

NASA Astrophysics Data System (ADS)

The astrophysical r-process is thought to be responsible for the creation of more than half of the elements heavier than iron. An explanation of the nuclide abundances requires information on masses, which are best obtained through direct measurements. The Canadian Penning Trap (CPT) mass spectrometer at Argonne National Laboratory has completed the measurement of 26 neutron-rich Ba, La, Ce, and Pr isotopes approaching the r-process path. The results of these measurements and their potential impact on the r-process are presented in this paper.

Clark, J. A.; Barber, R. C.; Boudreau, C.; Buchinger, F.; Crawford, J. E.; Greene, J. P.; Gulick, S.; Heinz, A.; Lee, J. K. P.; Levand, A. F.; Savard, G.; Scielzo, N.; Sharma, K. S.; Sprouse, G. D.; Trimble, W.; Vaz, J.; Wang, J. C.; Wang, Y.; Zabransky, B. Z.; Zhou, Z.

2004-09-01

11

Magnetic Protoneutron Star Winds and r-Process Nucleosynthesis  

Microsoft Academic Search

Because of their neutron richness and association with supernovae, postexplosion protoneutron star winds are thought to be a likely astrophysical site for rapid neutron-capture nucleosynthesis (the r-process). However, the most recent models of spherical neutrino-driven protoneutron star winds do not produce robust r-process nucleosynthesis for ``canonical'' neutron stars with a gravitational mass of 1.4 Msolar and coordinate radius of 10

Todd A. Thompson

2003-01-01

12

Sensitivity of the r-process to nuclear masses  

NASA Astrophysics Data System (ADS)

The rapid neutron capture process (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. 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. This work is an attempt to determine the most crucial nuclear masses to measure using an r-process simulation code and several mass models (FRDM, Duflo-Zuker, and HFB-21). The most important nuclear masses to measure are determined by the changes in the resulting r-process abundances. Nuclei around the closed shells near N = 50 , 82, and 126 have the largest impact on r-process abundances irrespective of the mass models used.

Brett, S.; Bentley, I.; Paul, N.; Surman, R.; Aprahamian, A.

2012-12-01

13

Facilitating Change Through a Simplified R and D Process.  

ERIC Educational Resources Information Center

|The paper suggests the application of a research and development (R and D) process in an ongoing project at the National Technical Institute for the Deaf. Four phases/stages of the process are discussed: research, development, implementation, and maintenance. It is pointed out that the objective of the project has been to train normal hearing…

Osguthorpe, Russell T.; Bishop, Milo E.

14

Where, oh where has the r-process gone?  

NASA Astrophysics Data System (ADS)

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 (from sources for heavy r-nuclei) and Fe (from Fe core-collapse supernovae). This model gives very good quantitative predictions for the abundances of all the other elements in those metal-poor stars with [Fe/H]?-1.5 for which the Eu and Fe abundances are known. We attribute the CPR elements such as Sr, Y, and Zr to reactions in the neutrino-driven winds from a nascent neutron star and the heavy r-nuclei to the hypothecated true “r-process”. The CPR nuclei should be produced whenever a neutron star is formed regardless of whether heavy r-nuclei are produced or not. Using the two-component model we estimate the yield of the CPR element Sr to be ˜10M for a single neutron star formation event. Self-consistent astrophysical models are needed to establish that the CPR nuclei are common to the neutron stars produced in both sources for the heavy r-nuclei and those for Fe. We show that the observational data appear fully consistent with the two-component model. The specific mechanism and site for the production of heavy r-nuclei remains to be found.

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

2007-04-01

15

R-process in Supernovae and Gamma-Ray Bursts  

SciTech Connect

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

Kajino, T.; Harikae, S. [National Astronomical Observatory of Japan, Mitaka, Tokyo, 181-8588 (Japan); Department of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yoshida, T. [Department of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Nakamura, K.; Aoki, W. [National Astronomical Observatory of Japan, Mitaka, Tokyo, 181-8588 (Japan)

2010-05-12

16

Collective neutrino oscillations and r-process nucleosynthesis in supernovae  

NASA Astrophysics Data System (ADS)

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

Duan, Huaiyu

2012-10-01

17

Magnetic Protoneutron Star Winds and r-Process Nucleosynthesis  

Microsoft Academic Search

Because of their neutron-richness and association with supernovae,\\u000apost-explosion protoneutron star winds are thought to be a likely astrophysical\\u000asite for rapid neutron capture nucleosynthesis (the r-process). However, the\\u000amost recent models of spherical neutrino-driven protoneutron star winds do not\\u000aproduce robust r-process nucleosynthesis for `canonical' neutron stars with a\\u000agravitational mass of 1.4M_sun and coordinate radius of 10km. These

Todd A. Thompson

2003-01-01

18

Nuclear Physics Issues of r-Process Nucleosynthesis  

SciTech Connect

Nucleosynthesis theory predicts that about half of the chemical elements above iron are formed in explosive stellar scenarios by the r-process, i.e. a combination of rapid neutron captures, inverse photodisintegrations, and slower {beta}-decays, {beta}-delayed processes, as well as fission and possibly interactions with neutrinos. A correct modelling of this process, therefore, requires the knowledge of nuclear properties very far from stability and a detailed description of the astrophysical environments. With respect to nuclear data, after an initial period of measuring classical 'waiting-point' nuclei with magic neutron numbers, recent investigations have paid special attention to shape transitions and the erosion of classical shell gaps with possible occurrence of new magic numbers. The status of experimental and theoretical nuclear data on masses and {beta}-decay properties will be briefly reviewed, and consequences on the overall r-process matter flow up to the cosmochronometers 232Th and 238U will be discussed.

Kratz, K.-L. [Institut fuer Kernchemie, Universitaet Mainz (Germany); HGF Virtual Institute for Nuclear Structure and Astrophysics, Mainz (Germany); Institute for Structure and nuclear Astrophysics, University of Notre Dame (United States)

2006-03-13

19

Nuclear Physics Data Relevant to r-Process Nucleosynthesis  

NASA Astrophysics Data System (ADS)

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

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

2005-05-01

20

The R&D cycle: the influence of product and process R&D on short-term ROI  

Microsoft Academic Search

The purposes of this paper are first to explore the relationship between the total R&D budget and two major components, product and process R&D, and second, to examine the relationship between these two types of R&D and the profitability of the business. The paper explores a cyclical pattern in the relationship between product and process R&D on the one hand

Jehiel Zif; Daniel J. McCarthy

1997-01-01

21

GOES-R AWG product processing system framework  

NASA Astrophysics Data System (ADS)

NOAA/NESDIS/STAR has designed, developed, and implemented the Geostationary Operational Environmental Satellite - R Series (GOES-R) Algorithm Working Group (AWG) Product Processing System Framework. The Framework enabled the development and testing of the Level 2 Advance Baseline Imager (ABI) and the GOES-R Lightning Mapper (GLM) products within a single system. Fifty-six GOES-R ABI algorithms and one GLM algorithm have been integrated and run within the framework with product precedence. The Framework has been modified to be a plug-and-play system with the scientific algorithms. To enable the plug-and-play capabilities, the fifty-seven ABI and GLM algorithms were adjusted such that any data required by the algorithm is brought into the algorithm through function calls. These modifications allowed an algorithm to be developed either within the Framework or within the scientist's offline research system. This approach provided both the algorithm developers and algorithm integrators the ability to work on the same software since the algorithm may be "dropped" into both systems resulting in simple algorithm rollbacks. The design features and the current status of the framework will be discussed.

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

2012-11-01

22

Explosive nucleosynthesis and the astrophysical r-process  

SciTech Connect

We give an overview of chemical equilibria in explosive burning and the role which neutron and/or proton separation energies play. We focus then on the rapid neutron-capture process (r-process) which encounters unstable nuclei far from beta-stability with neutron separation energies in the range 1-4 MeV. Its observable features, like the abundances, witness nuclear structure as well as the conditions in the appropriate astrophysical environment. With the remaining lack of a full understanding of its astrophysical origin, parametrized calculations are still necessary. The classical approach is based on (constant) neutron number densities n{sub n} and temperatures T over duration timescales {tau}. Recent investigations, motivated by the neutrino wind scenario from hot neutron stars after a supernova explosion, followed the expansion of matter with initial entropies S and electron fractions Y{sub e} over expansion timescales {tau}. We compare the similarities and differences between the two approaches with respect to resulting abundance features and their relation to solar r-process abundances. Special emphasis is given to the questions (i) whether the same nuclear properties far from stability lead to similar abundance patterns and deficiencies in both approaches and (ii) whether some features can also provide clear constraints on the permitted astrophysical conditions.

Thielemann, F.-K.; Freiburghaus, C.; Rauscher, T.; Kolbe, E. [Departement fuer Physik und Astronomie, Univ. Basel, Klinglbergstr. 82, CH-4056 Basel (Switzerland); Pfeiffer, B.; Kratz, K.-L. [Institut fuer Kernchemie, Univ. Mainz, Fritz-Strassmann-Weg 2, D-55099 Mainz (Germany); Cowan, J. J. [Department of Physics and Astronomy, Univ. of Oklahoma, Norman, Oklahoma 73019 (United States)

1998-12-21

23

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

NASA Astrophysics Data System (ADS)

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.

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

2011-04-01

24

R2 retrotransposons encode a self-cleaving ribozyme for processing from an rRNA cotranscript.  

PubMed

The non-long terminal repeat (non-LTR) retrotransposon R2 is inserted into the 28S rRNA genes of many animals. Expression of the element appears to be by cotranscription with the rRNA gene unit. We show here that processing of the rRNA cotranscript at the 5' end of the R2 element in Drosophila simulans is rapid and utilizes an unexpected mechanism. Using RNA synthesized in vitro, the 5' untranslated region of R2 was shown capable of rapid and efficient self-cleavage of the 28S-R2 cotranscript. The 5' end generated in vitro by the R2 ribozyme was at the position identical to that found for in vivo R2 transcripts. The RNA segment corresponding to the R2 ribozyme could be folded into a double pseudoknot structure similar to that of the hepatitis delta virus (HDV) ribozyme. Remarkably, 21 of the nucleotide positions in and around the active site of the HDV ribozyme were identical in R2. R2 elements from other Drosophila species were also shown to encode HDV-like ribozymes capable of self-cleavage. Tracing their sequence evolution in the Drosophila lineage suggests that the extensive similarity of the R2 ribozyme from D. simulans to that of HDV was a result of convergent evolution, not common descent. PMID:20421411

Eickbush, Danna G; Eickbush, Thomas H

2010-04-26

25

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

NASA Astrophysics Data System (ADS)

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.

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

2002-03-01

26

Hierarchical Segmentation of R&D Process and Intellectual Property Protection: Evidence From Multinational R&D Laboratories in China  

Microsoft Academic Search

This paper examines how multinational corporations (MNCs) protect their intellectual property (IP) when they conduct R&D in countries with weak IP rights (IPRs) protection. Findings from a small-scale survey and three case studies in China show that hierarchical segmentation of the R&D process can provide an effective way for IPR protection. Furthermore, a modular R&D structure adopted by many information

Xiaohong Quan; Henry Chesbrough

2010-01-01

27

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

SciTech Connect

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

Boyd, R. N. [Physics and Life Sciences, L-050, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Famiano, M. A. [Department of Physics and Joint Institute for Nuclear Astrophysics (JINA), Western Michigan University, 1903 W. Michigan Avenue, Kalamazoo, MI 49008-5252 (United States); Meyer, B. S. [Department of Physics and Astronomy, Clemson University, 118 Kinard Laboratory, Clemson, SC 29634-0978 (United States); Motizuki, Y. [RIKEN Nishina Center, Hirosawa 2-1, Wako 351-0198 (Japan); Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Mitaka, Tokyo 181-8588 (Japan); Roederer, I. U., E-mail: boyd11@llnl.gov [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

2012-01-15

28

Regulatory Effects on R/D are Better Assessed as Part of the Innovation Process.  

National Technical Information Service (NTIS)

Slow productivity growth has prompted concern that Federal regulations may be adversely affecting research and development (R/D) -- one part of the innovation process. GAO reviewed numerous studies of effects of Federal environmental, safety, and health r...

1982-01-01

29

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

NASA Astrophysics Data System (ADS)

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/.

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

2011-07-01

30

Standardization of the WISC-R in Puerto Rico: The Process and the Preliminary Findings.  

ERIC Educational Resources Information Center

|The process of adapting the Wechsler Intelligence Scale for Children-Revised (WISC-R) for Puerto Rico was begun with the following objectives: (1) to review the existing Spanish translation of the WISC-R; (2) to adapt the WISC-R to Puerto Rican culture and milieu; and (3) to standardize the scale with a representative sample of Puerto Rican…

Herrans, Laura L.; And Others

31

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

Microsoft Academic Search

In this paper we have analyzed the processing in vitro of the 16S rRNA of the thermophilic archaeon Sulfolobus solfataricus, using pre-rRNA substrates transcribed in vitro and different protein preparations as the source of processing enzymes. We show that the 5* external transcribed spacer of the S. solfataricus pre-rRNA transcript contains a target site for a specific endonuclease, which recognizes

ANDREA CIAMMARUCONI; PAOLA LONDEI

2001-01-01

32

mTOR signaling regulates the processing of pre-rRNA in human cells  

PubMed Central

Signaling through the mammalian target of rapamycin, complex 1 (mTORC1), positively regulates the transcription of ribosomal RNA (rRNA) and the synthesis of ribosomal proteins, thereby promoting the complex process of ribosome biogenesis. The major rRNAs are transcribed as a single precursor, which must be processed to create the 5.8S, 18S and 28S rRNAs. We used a new non-radioactive labeling approach to study the effects of rapamycin, an inhibitor of mTORC1, on rRNA synthesis. Rapamycin not only impaired synthesis of new 18S, 28S or 5S rRNA but also induced their decay. This prompted us to examine the effects of rapamycin on rRNA processing. We show that rapamycin also interferes with the processing events that generate 18S and 28S rRNA. rRNA transcription and processing occur in regions of the nucleus known as nucleoli. We find that the mTORC1 components raptor and mTOR are both present in nucleoli, where they may regulate rRNA maturation events. While rapamycin has no effect on overall nucleolar morphology or its proteome, it does induce loss of mTOR and raptor from them. These data show that mTORC1 is located in nucleoli where it acts to regulate events involved in ribosome biogenesis including the maturation of rRNA molecules.

Iadevaia, Valentina; Zhang, Ze; Jan, Eric; Proud, Christopher G.

2012-01-01

33

Waiting point approximation and canonical multi-event r-process revisited  

Microsoft Academic Search

The validity of the waiting point approximation on which canonical r-process calculations are commonly based is studied in detail in the astrophysical conditions of relevance by comparing its abundance predictions with those derived numerically from a full network calculation. Our network computations are also used to analyze the sensitivity of the derived r-process abundances to the astrophysical conditions of temperature,

S. Goriely; M. Arnould

1996-01-01

34

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

SciTech Connect

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.

Roederer, Ian U. [Carnegie Observatories, Pasadena, CA 91101 (United States); Lawler, James E. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Cowan, John J. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Frebel, Anna [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States); Ivans, Inese I. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Schatz, Hendrik [Department of Physics and Astronomy, Michigan State University, E. Lansing, MI 48824 (United States); Sobeck, Jennifer S. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Sneden, Christopher [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States)

2012-03-15

35

Radiation processing in india-current R & D activities  

NASA Astrophysics Data System (ADS)

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.

Majali, A. B.; Sabharwal, S.

1995-09-01

36

Processing of R-Ba-Cu-O superconductors.  

National Technical Information Service (NTIS)

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(...

H. Wu

1998-01-01

37

Prompt Iron Enrichment, Two r-Process Components, and Abundances in Very Metal-Poor Stars.  

PubMed

We present a model to explain the wide range of abundances for heavy r-process elements (mass number A>130) at low [Fe/H]. This model requires rapid star formation and/or an initial population of supermassive stars in the earliest condensed clots of matter in order to provide a prompt or initial Fe inventory. Subsequent Fe and r-process enrichment was provided by two types of supernovae: one producing heavy r-elements with no Fe on a rather short timescale and the other producing light r-elements (A

Wasserburg; Qian

2000-01-20

38

The r-process in metal poor stars and black hole formation  

NASA Astrophysics Data System (ADS)

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. We 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 we 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. We 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.

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

2012-11-01

39

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

SciTech Connect

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.

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

2011-11-30

40

Processing of R-Ba-Cu-O superconductors  

SciTech Connect

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

Wu, H.

1998-02-23

41

Beta-decay spectroscopy relevant to the r-process nucleosynthesis  

NASA Astrophysics Data System (ADS)

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 ?-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 ?-decay rates of the Zr and Nb isotopes around A = 110 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 ?-decay spectroscopy with the EURICA.

Nishimura, Shunji; RIBF Decay Collaboration

2012-11-01

42

Single and multi-event canonical r-process: astrophysics and nuclear physics considerations  

Microsoft Academic Search

We study the influence of nuclear mass formulae as well as beta-decay models on the r-abundance distribution resulting from canonical calculations of the nucleosynthesis r-process. This analysis is performed considering a single astrophysical event, or a more realistic superposition of events. We discuss conditions of validity of the waiting point approximation, propose an explanation of the smoothness of the r-elements

V. Bouquelle; N. Cerf; M. Arnould; T. Tachibana; S. Goriely

1996-01-01

43

Bypassing the rRNA processing endonucleolytic cleavage at site A2 in Saccharomyces cerevisiae.  

PubMed Central

Rrp5p is the only ribosomal RNA processing trans-acting factor that is required for the synthesis of both 18S and 5.8S rRNAs in Saccharomyces cerevisiae. Mutational analyses have characterized modified forms of Rrp5p that either affect formation of 18S rRNA by inhibiting cleavage at sites A0/A1/A2, or synthesis of 5.8S rRNA by inhibiting cleavage at site A3. Here, we examine the rRNA maturation process associated with a RRP5 bipartite allele that codes for two noncontiguous parts of the protein. This slow-growing bipartite mutant has a unique rRNA-processing phenotype that proceeds without endonucleolytic cleavage at site A2. In wild-type cells, the A2 cleavage takes place on the 32S pre-rRNA and is responsible for the formation of 20S and 27SA2 species, the precursors of mature 18S and 5.8S/25S rRNAs, respectively. In the bipartite strain, such precursors were not detectable as judged by Northern analysis or in vivo labeling. They were replaced by the aberrant 21S species and the bypassing 27SA3 precursor, both descended from direct cleavage of 32S pre-rRNA at site A3, which provides an alternative rRNA maturation pathway in this strain. The 21S pre-rRNA is the sole detectable and most likely available precursor of 18S rRNA in this particular strain, indicating that 18S rRNA can be directly produced from 21S. Furthermore, 21S species were found associated with 43S preribosomal particles as similarly observed for the 20S pre-rRNA in the wild-type cells.

Torchet, C; Hermann-Le Denmat, S

2000-01-01

44

A functional interface at the rDNA connects rRNA synthesis, pre-rRNA processing and nucleolar surveillance in budding yeast.  

PubMed

Ribogenesis is a multistep error-prone process that is actively monitored by quality control mechanisms. How ribosomal RNA synthesis, pre-rRNA processing and nucleolar surveillance are integrated is unclear. Nor is it understood how defective ribosomes are recognized. We report in budding yeast that, in vivo, the interaction between the transcription elongation factor Spt5 and Rpa190, the largest subunit of RNA polymerase (Pol) I, requires the Spt5 C-terminal region (CTR), a conserved and highly repetitive domain that is reminiscent of the RNA Pol II C-terminal domain (CTD). We show that this sequence is also required for the interaction between Spt5 and Nrd1, an RNA specific binding protein, and an exosome cofactor. Both the Spt4-Spt5, and the Nrd1-Nab3 complexes interact functionally with Rrp6, and colocalize at the rDNA. Mutations in the RNA binding domain of Nrd1, but not in its RNA Pol II CTD-interacting domain, and mutations in the RRM of Nab3 led to the accumulation of normal and aberrant polyadenylated pre-rRNAs. Altogether these results indicate that Nrd1-Nab3 contributes to recruiting the nucleolar surveillance to elongating polymerases to survey nascent rRNA transcripts. PMID:21949810

Leporé, Nathalie; Lafontaine, Denis L J

2011-09-19

45

Organizational behavior in the R&D process based on patent analysis  

Microsoft Academic Search

In the previous study [Tsuji, Org. Sci. 33 (2000) 62], the author showed that Canon's patent acquisition strategy effectively promotes their research and development (R&D). In the present study, the author investigated Canon's R&D process from the viewpoint of organizational behavior, paying particular attention to researchers' behavioral patterns, the significance of their patent acquisition strategy, and the role of the

Youichirou S Tsuji

2002-01-01

46

Process Systems Engineering R&D for Advanced Fossil Energy Systems  

SciTech Connect

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.

Zitney, S.E.

2007-09-11

47

Nucleosynthesis of Light Elements and Heavy r-Process Elements through the nu-Process in Supernova Explosions  

Microsoft Academic Search

We study the nucleosynthesis of the light elements 7Li and 11B and the r-process elements in Type II supernovae from the point of view of supernova neutrinos and Galactic chemical evolution. We investigate the influence of the luminosity and average energy (temperature) of supernova neutrinos on these two nucleosynthesis processes. Common models of the neutrino luminosity, which is parameterized by

Takashi Yoshida; Mariko Terasawa; Toshitaka Kajino; Kohsuke Sumiyoshi

2004-01-01

48

The Astrophysical r-Process 50 Years after B2FH  

NASA Astrophysics Data System (ADS)

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 80Zn and 130Cd could be obtained, which act as key ``waiting points'' in the respective A~=80 and 130 peaks of the Solar-System (SS) r-abundances (Nr,solar). Since then, using steadily improved nuclear data, we have optimized our r-process calculations to reproduce the present observables of the isotopic Nr,solar ``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.

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

2008-01-01

49

The r-process nucleosynthesis in an expanding hot bubble in supernovae explosion  

NASA Astrophysics Data System (ADS)

The r-process is one of the major nucleosynthesis processes responsible for the production of heavy elements beyond iron. Recent models of r-process nucleosynthesis rely on a neutrino-heated bubble developing at late times, which provides both the necessary conditions and the requisite amount of ejected mass for the r-process (Wooseley et al '94) . In the neutrino-driven explosion, only a small amount of matter is heated to the requisite high specific energy and entropy. Meyer et al (1992) first calculated the r-process under conditions appropriate to a neutrino-heated bubble and found that the solar r-process abundances could be replicated. They showed that the hot bubble that forms outside the protoneutron star during a SN explosion may be a viable site for the r-process as long as the entropy per baryon can be made sufficiently high. But in a very neutron rich environment such as a neutron star , the r-process could occur even at low entropy (Cowan and Thielemann, 2004). The high entropy wind is not the correct r-process site , owing to the inherent deficiencies in the abundance pattern below A=110 as well as the problems in obtaining the high entropies in SN II explosions required for producing the massive r-process nuclei up to A ? 195 and beyond ( Freiburghaus et al., 1999). Modelers of r-process nucleosynthesis find the entropy of the expanding matter and the overall n/p ratio to be more useful parameter than the temp and neutron density. We have tried to associate the explosion entropies with the site-independent classical approach (n[n] and T) and thereby compare the results of the two approaches from the abundances at different entropy conditions. We find that en entropy of ? 300 with Y[e] ? 0.45 can lead to a successful r-process. This is in agreement with the r-process abundance peaks at n[n] ? 10^32 cm^-3 and T[9] ? 1.5 . References : 1. Cowan J.J. and Thielemann F. K., Physics Today, 2004 2. Woosley S.E., Wilson J.R., Mathews G. J., Hoffman R.D. and Meyer B.S., 1994, ApJ, 433, 229 3. Takahashi K., Witti J. and Janka H.-Th., 1994, A & A , 286, 857 4. Meyer B. S., Mathews G. J., Howard W. M., Woosley S. E. and Hoffman R.D.,1992, ApJ, 399, 656 5. Freiburghaus C., Rembges J. F., Rauscher T.,Kolbe E., Thielemann F. K., kratz K. L., Pfeiffer B. and Cowan J. J., 1999, ApJ, 516, 381

Baruah, Rulee; Duorah, H. L.; Duorah, K.

2006-08-01

50

Hierarchical Chemical Evolution and R-process Elements of Extremely Metal-Poor Stars  

NASA Astrophysics Data System (ADS)

We present results of the new chemical evolution model which focus on extremely metal-poor (EMP) stars and discuss r-process element abundances. We built a merger tree of the Galaxy and follow the enrichment of the chemical abundance along the tree. We also follow the inhomogeneous metal enrichment process of intergalactic matter and surface pollution of EMP stars by accretion of interstellar matter (ISM). Our model well reproduces observed abundance distributions. O-Ne-Mg supernovae with 9-10 M? are the most plausible source of the r-process elements.

Komiya, Y.; Yamada, S.; Suda, T.; Fujimoto, M. Y.

2012-08-01

51

Core Collapse Supernovae and the r-Process: An Amalgam of Current Ideas  

NASA Astrophysics Data System (ADS)

After several decades of research the sites for the rapid neutron capture process (i.e. the r-process) have not been unequivocally identified. However, it is generally agreed upon that the most likely candidates are type II supernovae. We will be using a renovated 1D core collapse supernova simulation that utilizes full general relativity and runs out to late times. In this talk we will discuss using this simulation in conjunction with the latest r-process nuclear abundance calculations. We will address the critical role played by the neutrino-energized high entropy bubble in the nucleosynthesis of heavy nuclei.

Meixner, Matthew; Mathews, Grant; Wilson, James; Otsuki, Kaori

2007-10-01

52

Shell-model calculations of beta-decay rates for s- and r-process nucleosyntheses  

NASA Astrophysics Data System (ADS)

Examples of large-basis shell-model calculations of Gamow-Teller (BETA)-decay properties of specific interest in the astrophysical s- and r- processes are presented. Numerical results are given for: (1) the GT-matrix elements for the excited state decays of the unstable s-process nucleus Tc-99; and (2) the GT-strength function for the neutron-rich nucleus Cd-130, which lies on the r-process path. The results are discussed in conjunction with the astrophysics problems.

Takahashi, K.; Mathews, G. J.; Bloom, S. D.

1985-10-01

53

Fission modes of neutron-rich nuclei in the r-process nucleosynthesis  

SciTech Connect

The fission fragments mass distribution (FFMD) which is the important nuclear information in the study of the r-process nucleosynthesis is estimated for the neutron-rich nuclei (Z>85) according to the theoretical investigation of the potential energy surface. The details for determining FFMD are discussed. In this paper, the network calculation on the r-process nucleosynthesis is also performed including the data of FFMD. The comparison of the results of the network calculation, with and without the fission processes, is shown.

Tatsuda, S.; Yamamoto, K.; Asano, T.; Ohta, M. [Department of Physics, Konan University, 8-9-1 Okamoto, Kobe658-8501 (Japan); Wada, T. [Kansai Univ. (Japan); Chiba, S.; Koura, H.; Maruyama, T. [JAEA (Japan); Tachibana, T. [Waseda Univ. (Japan); Kajino, T. [NAO (Japan); Sumiyoshi, K. [Numazu College of Technology (Japan); Otsuki, K. [Univ. of Chicago (United States)

2008-05-21

54

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

NASA Astrophysics Data System (ADS)

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).

Heymann, D.; Liffman, K.

1986-03-01

55

Desequilibrio (n,gamma) (gamma,n) no processo-r de nucleosintese. ((n,gamma) (gamma,n) unstability in the r process of nucleosynthesis).  

National Technical Information Service (NTIS)

The equilibrium approximation for capture and neutron photoemission reactions within r process of nucleosynthesis is analysed. This analysis is considered for whole range of neutron density and temperature which enable the ocurrence of the process. In thi...

S. J. B. Duarte

1977-01-01

56

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

SciTech Connect

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.

Wanajo, Shinya [Technische Universitaet Muenchen, Excellence Cluster Universe, Boltzmannstr. 2, D-85748 Garching (Germany); Janka, Hans-Thomas, E-mail: shinya.wanajo@universe-cluster.de, E-mail: thj@mpa-garching.mpg.de [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)

2012-02-20

57

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

NASA Astrophysics Data System (ADS)

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

Wanajo, Shinya; Janka, Hans-Thomas

2012-02-01

58

Characterization by 13C n.m.r. spectroscopy of base oils produced by different processes  

Microsoft Academic Search

The hydrocarbon composition of base oils produced by different processes—hydrotreatments (hydrocracking and wax isomerization), solvent refining plus hydrofinishing, and severe hydrofinishing—were determined by 13C n.m.r. spectroscopy. Structural parameters such as normal and iso-paraffin contents, average chain length and number of branching sites were estimated by new equations derived after complete assignment of signals in the 5–21 ppm 13C n.m.r. region.

Amarjeet S. Sarpal; Gurpreet S. Kapur; Suman Mukherjee; Surendra K. Jain

1997-01-01

59

r-Process Nucleosynthesis in Hot Accretion Disk Flows from Black Hole - Neutron Star Mergers  

SciTech Connect

We consider hot accretion disk outflows from black hole-neutron star mergers in the context of the nucleosynthesis they produce. We begin with a three-dimensional numerical model of a black hole-neutron star merger and calculate the neutrino and antineutrino fluxes emitted from the resulting accretion disk. We then follow the element synthesis in material outflowing the disk along parameterized trajectories. We find that at least a weak r-process is produced, and in some cases a main r-process as well. The neutron-rich conditions required for this production of r-process nuclei stem directly from the interactions of the neutrinos emitted by the disk with the free neutrons and protons in the outflow.

Surman, Rebecca [Union College; Mclaughlin, Gail C [North Carolina State University; Ruffert, Maximilian [University of Edinburgh; Janka, Hans-Thomas [Max Planck Institut fur Astrophysik (MPA), Germany; Hix, William Raphael [ORNL

2008-01-01

60

Beta-decay spectroscopy relevant to the r-process nucleosynthesis  

SciTech Connect

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.

Nishimura, Shunji [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Collaboration: RIBF Decay Collaboration

2012-11-12

61

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

PubMed

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

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

2013-08-05

62

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

PubMed

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

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

2013-10-07

63

Observing the signatures of the r-process in metal-poor stars  

NASA Astrophysics Data System (ADS)

In their atmospheres, old metal-poor Galactic stars retain detailed information about the chemical composition of the interstellar medium at the time of their birth. Extracting such stellar abundances enables us to reconstruct the beginning of the chemical evolution shortly after the Big Bang. About 5% of metal-poor stars with [Fe/H]<-2.5 display in their spectrum a strong enhancement of neutron-capture elements associated with the rapid (r-) nucleosynthesis process that is responsible for the production of the heaviest elements in the Universe. This fortuity provides a unique opportunity of bringing together astrophysics and nuclear physics because these objects act as ``cosmic lab'' for both fields of study. The so-called r-process stars are thought to have formed from material enriched in heavy neutron-capture elements that were created during an r-process event in a previous generation SN. It appears that the few stars known with this rare chemical signature all follow the scaled solar r-process pattern (for the heaviest elements with 56r-process is universal -- a surprising empirical finding and a solid result that can not be obtained from any laboratory on earth. It is thus a crucial constraint for theoretical nuclear physices models. Among the heaviest elements are the long-lived radioactive isotopes ^232Th (half-life 14 Gyr) and ^238U (4.5 Gyr). While Th is often detectable in these stars, U poses a real challenge because only one, extremely weak line is available in the optical spectrum. In comparison with stable r-process nuclei, such as Eu, stellar ages can be derived from abundance ratios involving Th and/or U. Through individual age measurements, these objects become vital probes for observational ``near-field'' cosmology by providing an independent lower limit for the age of the Universe.

Frebel, Anna

2008-04-01

64

Beta-delayed fission calculations for the astrophysical r-process  

SciTech Connect

We discuss RPA calculations of the Gamow-Teller properties of neutron-rich nuclei to study the effect of ..beta..-delayed fission and neutron emission on the production of Th, U and Pu chronometric nuclei in the astrophysical r-process. We find significant differences in the amount of ..beta..-delayed fission when compared with the recent calculations of Thielemann et al. (1983). In the simplest case of a constant abundance along the r-process path, however, the inferred production ratios in both calculations are similar.

Meyer, B.S.; Howard, W.M.; Mathews, G.J.; Moeller, P.; Takahashi, K.

1985-10-09

65

PhenomiR: a knowledgebase for microRNA expression in diseases and biological processes.  

PubMed

In recent years, microRNAs have been shown to play important roles in physiological as well as malignant processes. The PhenomiR database http://mips.helmholtz-muenchen.de/phenomir provides data from 542 studies that investigate deregulation of microRNA expression in diseases and biological processes as a systematic, manually curated resource. Using the PhenomiR dataset, we could demonstrate that, depending on disease type, independent information from cell culture studies contrasts with conclusions drawn from patient studies. PMID:20089154

Ruepp, Andreas; Kowarsch, Andreas; Schmidl, Daniel; Buggenthin, Felix; Brauner, Barbara; Dunger, Irmtraud; Fobo, Gisela; Frishman, Goar; Montrone, Corinna; Theis, Fabian J

2010-01-20

66

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

67

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

SciTech Connect

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.

Fellinger, A.

2009-10-15

68

Processing effects in aluminum micro-channel tube for brazed R744 heat exchangers  

Microsoft Academic Search

The effects of processing on the mechanical behavior of aluminum alloy micro-channel tubing used in brazed automotive heat exchangers are evaluated in light of the stringent requirements of CO2 (R744 refrigerant) based systems. An apparatus was developed to simulate system operating conditions of pressure and elevated temperature in tube samples. Commercially extruded and processed AA3102 micro-channel tube samples were given

Gowreesan Vamadevan; Frank F. Kraft

2007-01-01

69

Supernova Neutrinos and Their Influence on Nucleosynthesis:. Light Elements and R-Process Elements  

Microsoft Academic Search

The influence of the neutrino luminosity on the nucleosynthesis of the light elements 7Li and 11B and the r-process heavy elements in Type II Supernovae is investigated. Common models of the neutrino luminosity, which are parameterized by the total energy Enu and decay time taunu, are adopted to understand both processes. The supernova explosion of a 16.2 M&sun; star, which

Takashi Yoshida; Mariko Terasawa; Toshitaka Kajino; Kohsuke Sumiyoshi

2005-01-01

70

Heres: the Search for R-Process Enhanced, Metal-Poor Stars  

NASA Astrophysics Data System (ADS)

In recent years a handful of extremely metal-deficient stars have been identified that exhibit moderate to large enhancements of their abundance ratios (relative to Fe) of elements associated with the astrophysical r-process enabling detections of radioactive species such as U and Th. Our understanding could be greatly improved by increasing the numbers of known r-process-enhanced metal-poor stars as well from building the sample to the point where meaningful measures of the frequency of the phenomenon especially as a function of metallicity could be ascertained. We describe the present status of HERES -- The Hamburg/ESO R-process Enhanced Star survey. This survey is based upon ""snapshot"" high-resolution VLT/UVES spectra of large numbers of giants with [Fe/H] < -2.5. Spectra of sufficient quality to detect the presence of the EuII line (4019 A) a distinctive neutron-capture feature have now been obtained for some 150-200 extremely metal-deficient giants chosen from the Hamburg/ESO survey. We discuss the number of moderate- and highly r-process enhanced stars discovered update our estimate of the frequency of their detection and present a discussion of the distribution of ~ 20 other easily measured elements in each of these stars (e.g. C Ca Mg Si Co Ni Sr Ba etc.).

Beers, Timothy C.; Christlieb, Norbert; Bessell, Mike S.; Hill, Vanessa; Barklem, Paul S.; Ryan, Sean G.; Rossi, Silvia; Korn, Andreas

71

Current R & D activities at TRCRE in polymer processing by EB  

NASA Astrophysics Data System (ADS)

The current status of the R & D activities is presented on electron beam processing of polymers being carried out at TRCRE. Topics included are sterilization of medical products, graft polymers for selective separation or absorbents and curing of liquid prepolymer-monomer systems.

Yoshii, F.; Sugo, T.; Sasaki, T.; Makuuchi, K.; Ishigaki, I.

1993-07-01

72

The neutrino-induced neutron source in helium shell and r-process nucleosynthesis  

Microsoft Academic Search

The huge neutrino pulse that occurs during the collapse of a massive stellar core, is expected to contribute to the origination of a number of isotopes both of light chemical elements and heavy ones. In particular, evaporation of neutrons from helium nuclei excited by neutrino-nuclear inelastic collisions, may result in the r-process as it was first discussed by Epstein et

D. K. Nadyozhin; I. V. Panov; S. I. Blinnikov

1998-01-01

73

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

74

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

SciTech Connect

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

Nakamrua, Ko; Harikae, Seiji; Kajino, Toshitaka; Mathews, Grant J. [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo, 181-8588 (Japan); Quants Research Department, Financial Engineering Division, Mitsubishi UFJ Morgan Stanley Securities Co., Ltd. (Japan); National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo, 181-8588 and Department of Astronomy, School of Science, University of Tokyo, Tokyo, 113-0033 (Japan); Center for Astrophysics, Department of Physics, University of Notre Dame, IN 46556 (United States)

2012-11-12

75

The r-process: recent progress and needs for nuclear data  

NASA Astrophysics Data System (ADS)

Several nuclear physics issues essential to understanding the r-process are discussed. These include validity of the waiting-point approximation, strength of closed neutron shells in neutron-rich nuclei far from stability, and effects of neutrino interaction with such nuclei. The needs for nuclear data in resolving these issues are emphasized.

Qian, Y.-Z.

2004-12-01

76

Supernova Neutrino Effects on r-Process Nucleosynthesis in Black Hole Formation  

NASA Astrophysics Data System (ADS)

Very massive stars with mass >=8 Msolar culminate their evolution by supernova explosions, which are presumed to be the most viable candidates for the astrophysical sites of r-process nucleosynthesis. If the models for the supernova r-process are correct, then the results of nucleosynthesis could also put a significant constraint on the remnants of supernova explosions, i.e., a neutron star or black hole. In the case of very massive core collapse for a progenitor mass 20-40 Msolar, a remnant stellar black hole is thought to be formed. Intense neutrino flux from the neutronized core and the neutrinosphere might suddenly cease during the Kelvin-Helmholtz cooling phase because of the black hole formation. It is important and interesting to explore the observable consequences of such a neutrino flux truncation. It has recently been argued in the literature that even the neutrino mass can be determined from the time delay of the deformed neutrino energy spectrum after the cessation of neutrino ejection (neutrino cutoff effect). Here we study the expected theoretical response of the r-process nucleosynthesis to the neutrino cutoff effect in order to look for another independent signature of this phenomenon. We found a sensitive response of the r-process yield if the neutrino cutoff occurs after the critical time when the expanding materials in the neutrino-driven wind drop out of nuclear statistical equilibrium (NSE). The r-process nucleosynthesis yields drastically change if the cutoff occurs during the r-process, having maximal effect on the change in abundance of 232Th and 235,238U. There is a large probability of finding this effect in elemental abundances of r-process-enhanced metal-deficient halo stars whose chemical composition is presumed to be affected by Population III supernovae in the early Galaxy. Using this result, connected with future detection of the time variation of the SN neutrino spectrum, we are able to identify when the black hole formation occurs in the course of SN collapse.

Sasaqui, T.; Kajino, T.; Balantekin, A. B.

2005-11-01

77

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

NASA Astrophysics Data System (ADS)

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-to-seed ratios, and lower entropies, and/or higher electron abundances. Conclusions: Our analysis confirms that Pd and Ag form via a rapid neutron-capture process that differs from the main r-process, the main and weak s-processes, and charged particle freeze-outs. We find that this process is efficiently working down to the lowest metallicity sampled by our analysis ([Fe/H] = - 3.3). Our results may indicate that a combination of these explosive sites is needed to explain the variety in the observationally derived abundance patterns. Based on observations made with the ESO Very Large Telescope at Paranal Observatory, Chile (ID 65.L-0507(A), 67.D-0439(A), 68.B-0475(A), 68.D-0094(A), 71.B-0529(A); P.I. F. Primas).Appendices are available in electronic form at http://www.aanda.org

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

78

Processing of truncated mouse or human rRNA transcribed from ribosomal minigenes transfected into mouse cells.  

PubMed Central

The processing of pre-rRNA in eukaryotic cells involves a complex pattern of nucleolytic reactions taking place in preribosomes with the participation of several nonribosomal proteins and small nuclear RNAs. The mechanism of these reactions remains largely unknown, mainly because of the absence of faithful in vitro assays for most processing steps. We have developed a pre-rRNA processing system using the transient expression of ribosomal minigenes transfected into cultured mouse cells. Truncated mouse or human rRNA genes are faithfully transcribed under the control of mouse promoter and terminator signals. The fate of these transcripts is analyzed by the use of reporter sequences flanking the rRNA gene inserts. Both mouse and human transcripts, containing the 3' end of 18S rRNA-encoding DNA (rDNA), internal transcribed spacer (ITS) 1, 5.8S rDNA, ITS 2, and the 5' end of 28S rDNA, are processed predominantly to molecules coterminal with the natural mature rRNAs plus minor products corresponding to cleavages within ITS 1 and ITS 2. To delineate cis-acting signals in pre-rRNA processing, we studied series of more truncated human-mouse minigenes. A faithful processing at the 18S rRNA/ITS 1 junction can be observed with transcripts containing only the 60 3'-terminal nucleotides of 18S rRNA and the 533 proximal nucleotides of ITS 1. However, further truncation of 18S rRNA (to 8 nucleotides) or of ITS 1 (to 48 nucleotides) abolishes the cleavage of the transcript. Processing at the ITS 2/28S rRNA junction is observed with truncated transcripts lacking the 5.8S rRNA plus a major part of ITS 2 and containing only 502 nucleotides of 28S rRNA. However, further truncation of the 28S rRNA segment to 217 nucleotides abolishes processing. Minigene transcripts containing most internal sequences of either ITS 1 or ITS 2, but devoid of ITS/mature rRNA junctions, are not processed, suggesting that the cleavages in vivo within either ITS segment are dependent on the presence in cis of mature rRNA sequences. These results show that the major cis signals for pre-rRNA processing at the 18S rRNA/ITS 1 or the ITS2/28S rRNA junction involve solely a limited critical length of the respective mature rRNA and adjacent spacer sequences. Images

Hadjiolova, K V; Normann, A; Cavaille, J; Soupene, E; Mazan, S; Hadjiolov, A A; Bachellerie, J P

1994-01-01

79

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

SciTech Connect

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

Spielberger, L.; Klein, J.

1981-05-01

80

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

SciTech Connect

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.

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

2006-07-01

81

What are the astrophysical sites for the r-process and the production of heavy elements?  

NASA Astrophysics Data System (ADS)

This article addresses three of the four nucleosynthesis processes involved in producing heavy nuclei beyond Fe (with a main focus on the r-process). Opposite to the fourth process (the s-process), which operates in stellar evolution during He- and C-burning, they are all related to explosive burning phases, (presumably) linked to core collapse supernova events of massive stars. The (classical) p-process is identified with explosive Ne/O-burning in outer zones of the progenitor star. It is initiated by the passage of the supernova shock wave and acts via photodisintegration reactions like a spallation process which produces neighboring (proton-rich) isotopes from pre-existing heavy nuclei. The reproduction of some of the so-called lighter p-isotopes with A<100 faces problems in this environment. The only recently discovered ?p-process is related to the innermost ejecta, the neutrino wind expelled from the hot proto-neutron star after core collapse and the supernova explosion. This neutrino wind is proton-rich in its early phase, producing nuclei up to 64Ge. Reactions with neutrinos permit to overcome decay/reaction bottlenecks for the flow beyond 64Ge, thus producing light p-isotopes, which face problems in the classical p-process scenario. The understanding of the r-process, being identified for a long time with rapid neutron captures and passing through nuclei far from stability, is still experiencing major problems. These are on the one hand related to nuclear uncertainties far from stability (masses, half-lives, fission barriers), affecting the process speed and abundance peaks. On the other hand the site is still not definitely located, yet. (i) Later, possibly neutron-rich, high entropy phases of the neutrino wind (if they materialize!) could permit its operation. (ii) Other options include the ejection of very neutron-rich neutron star-like matter, occurring possibly in neutron star mergers or core collapse supernova events with jets, related to prior stellar evolution with high rotation rates and magnetic fields. Two different environments are required for a weak and a main/strong r-process, witnessed by observations of low metallicity stars and meteoritic inclusions, which could possibly be identified with the two options listed above, i.e. the weak r-process could be related to the neutrino wind when changing from p-rich to n-rich conditions.

Thielemann, F.-K.; Arcones, A.; Käppeli, R.; Liebendörfer, M.; Rauscher, T.; Winteler, C.; Fröhlich, C.; Dillmann, I.; Fischer, T.; Martinez-Pinedo, G.; Langanke, K.; Farouqi, K.; Kratz, K.-L.; Panov, I.; Korneev, I. K.

2011-04-01

82

Roles of glucitol in the GutR-mediated transcription activation process in Bacillus subtilis: tight binding of GutR to tis binding site.  

PubMed

Glucitol induction in Bacillus subtilis requires a transcription activator, GutR, and a sequence located upstream of the gut promoter. To understand the initial steps involved in the GutR-mediated transcription activation process and the physiological roles of glucitol, GutR was overproduced and purified. In the absence of glucitol, GutR exists as a monomer and binds directly to its binding site in the gut regulatory region. This binding site was mapped to a 29-base pair imperfect inverted repeat located between -78 and -50, and there is only one GutR binding site within the regulatory region. The kinetic parameters of the interaction between GutR and its binding site were monitored in real time using surface plasmon resonance. The half-life of the GutR-DNA complex in the absence of glucitol was estimated to be 6.8 min. In contrast, in the presence of glucitol, the half-life of the complex was extended to longer than 19 h by affecting only the off-rate but not the on-rate. This effect is glucitol-specific. These data indicate that glucitol binds to GutR and induces GutR to have an extremely tight binding at its binding site. The physiological relevance of this process in transcription activation is discussed. PMID:11118449

Poon, K K; Chen, C L; Wong, S L

2000-12-15

83

MAGNETOROTATIONALLY DRIVEN SUPERNOVAE AS THE ORIGIN OF EARLY GALAXY r-PROCESS ELEMENTS?  

SciTech Connect

We examine magnetorotationally driven supernovae as sources of r-process elements in the early Galaxy. On the basis of thermodynamic histories of tracer particles from a three-dimensional magnetohydrodynamical core-collapse supernova model with approximated neutrino transport, we perform nucleosynthesis calculations with and without considering the effects of neutrino absorption reactions on the electron fraction (Y{sub e} ) during post-processing. We find that the peak distribution of Y{sub e} in the ejecta is shifted from {approx}0.15 to {approx}0.17 and broadened toward higher Y{sub e} due to neutrino absorption. Nevertheless, in both cases, the second and third peaks of the solar r-process element distribution can be reproduced well. The rare progenitor configuration that was used here, characterized by a high rotation rate and a large magnetic field necessary for the formation of bipolar jets, could naturally provide a site for the strong r-process in agreement with observations of the early Galactic chemical evolution.

Winteler, C.; Perego, A.; Vasset, N.; Nishimura, N.; Liebendoerfer, M.; Thielemann, F.-K. [Physics Department, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Kaeppeli, R. [Seminar for applied Mathematics, ETH Zuerich, Raemistrasse 101, 8092 Zuerich (Switzerland); Arcones, A., E-mail: christian.winteler@unibas.ch [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 2, D-64289 Darmstadt (Germany)

2012-05-01

84

12B(n,g) - The Influence on r-process Nucleosynthesis of Light Elements  

NASA Astrophysics Data System (ADS)

Astrophysical models predict enhanced abundances for heavy elements produced in the r-process by extending the reaction network to include light, neutron-rich nuclei (Z<=10). The independent study in search for the most influential reactions producing the final r-process abundances emphasize the importance of improved experimental data, especially for (n,?) reaction rates with unstable nuclei. Based on this analysis, ^12B(n,?)^13B is found to be one of most important light-mass nuclear reactions. We have measured the (d,p) reaction with radioactive ^12B beam for the first time using the ATLAS in-flight facility at Argonne. The spectroscopic factors determined from this measurement will be used to compare to theoretical calculations and the astrophysical implications using experimentally determined reaction rates will be discussed.

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.; Tang, X.; Patel, N.

2008-10-01

85

New Precision Mass Measurements of Heavy ^252Cf Fission Fragments Near the r-Process Path  

NASA Astrophysics Data System (ADS)

Precision mass measurements of nuclides near the astrophysical r-process path are vital to reduce the uncertainties in the relevant neutron separation energies given by mass models, and the consequent abundance predictions. As part of an ongoing program, the Canadian Penning Trap mass spectrometer at Argonne National Laboratory has measured the masses of fission products from a ^252Cf source in a large-volume gas catcher. This has produced 38 new mass measurements of neutron-rich nuclides ranging from Z=51 to 64, many closer to the r-process path than had previously been measured for these elements. Systematic deviations from the AME 2003 are seen over a wide range of elements. The program of mass measurements will continue at the CARIBU upgrade to the ATLAS accelerator at ANL this fall.

van Schelt, J.; Savard, G.; Caldwell, S.; Sternberg, M.; Clark, J. A.; Greene, J. P.; Levand, A. F.; Sun, T.; Zabransky, B. J.; Fallis, J.; Sharma, K. S.; Lascar, D.; Segel, R. E.; Li, G.

2009-10-01

86

HERES: The Search for r-Process-Enhanced, Metal-Poor Stars  

NASA Astrophysics Data System (ADS)

In recent years, a handful of extremely metal-deficient stars have been identified that exhibit moderate to large enhancements of their abundance ratios (relative to Fe) of elements associated with the astrophysical r-process, enabling detections of radioactive species such as U and Th. Our understanding could be greatly improved by increasing the numbers of known r-process-enhanced, metal-poor stars, as well from building the sample to the point where meaningful measures of the frequency of the phenomenon, especially as a function of metallicity, could be ascertained. We describe the present status of HERES -- The Hamburg/ESO R-process Enhanced Star survey. This survey is based upon "snapshot" high-resolution VLT/UVES spectra of large numbers of giants with [Fe/H] < -2.5. Spectra of sufficient quality to detect the presence of the EuII line (4019 Å ), a distinctive neutron-capture feature, have now been obtained for over 300 very metal-deficient giants chosen from the Hamburg/ESO survey, along with a small number of targets from the HK survey of Beers and colleagues. We discuss the number of moderate- and highly- r-process enhanced stars discovered, update our estimate of the frequency of their detection, and present a discussion of the distribution of ˜ 20 other easily-measured elements in each of these stars (e.g., C, Ca, Mg, Si, Co, Ni, Sr, Ba, etc.). This work has received partial support from NSF grants AST 00-98508 and AST 00-98549. Support has also been received from the Deutsche Forschungsgemeinschaft (Re 353/44-1), the Swedish Research Council, PPARK (UK: PPA/O/S/1998/00658), FAPESP and CNPq (Brazil).

Beers, T. C.; Christlieb, N.; Bessell, M. S.; Hill, V.; Barklem, P. S.; Korn, A.; Ryan, S. G.; Rossi, S.; Rhee, J.

2003-12-01

87

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

PubMed Central

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

Schillewaert, Stephanie; Wacheul, Ludivine; Lhomme, Frederic

2012-01-01

88

The evolutionarily conserved protein Las1 is required for pre-rRNA processing at both ends of ITS2.  

PubMed

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

Schillewaert, Stéphanie; Wacheul, Ludivine; Lhomme, Frédéric; Lafontaine, Denis L J

2011-11-14

89

Influence of spontaneous fission rates on the yields of superheavy elements in the r-process  

NASA Astrophysics Data System (ADS)

The formation of heavy elements in the neutron star merger scenario is considered. In such a scenario, the duration of the r-process is long and when the nucleosynthesis wave passes through the region of actinides, beta-delayed, neutron-induced, and spontaneous fission are added to the main r-process reaction channels. The dependence of the formation of superheavy elements on spontaneous fission model is investigated numerically. The formation of nuclei lighter than the cadmium-peak elements and cosmochronometer nuclei is shown to depend on strongly on the spontaneous fission model used in nucleosynthesis calculations. The regions of nuclei with short spontaneous fission half-lives prevent the formation of superheavy elements in the r-process, but the prediction of their yields is so far inaccurate because of an insufficient accuracy of calculating a number of transactinide parameters. The relative contributions from neutron-induced, beta-delayed, and spontaneous fission have been determined for various spontaneous fission models in the nucleosynthesis scenario considered.

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

2013-03-01

90

a Review of r-PROCESS Nucleosynthesis in the Collapsar Jet  

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

91

Analysis of rRNA processing and translation in mammalian cells using a synthetic 18S rRNA expression system  

PubMed Central

Analysis of processing, assembly, and function of higher eukaryotic ribosomal RNA (rRNA) has been hindered by the lack of an expression system that enables rRNA to be modified and then examined functionally. Given the potential usefulness of such a system, we have developed one for mammalian 18S rRNA. We inserted a sequence tag into expansion segment 3 of mouse 18S rRNA to monitor expression and cleavage by hybridization. Mutations were identified that confer resistance to pactamycin, allowing functional analysis of 40S ribosomal subunits containing synthetic 18S rRNAs by selectively blocking translation from endogenous (pactamycin-sensitive) subunits. rRNA constructs were suitably expressed in transfected cells, shown to process correctly, incorporate into ?15% of 40S subunits, and function normally based on various criteria. After rigorous analysis, the system was used to investigate the importance of sequences that flank 18S rRNA in precursor transcripts. Although deletion analysis supported the requirement of binding sites for the U3 snoRNA, it showed that a large segment of the 5? external transcribed spacer and the entire first internal transcribed spacer, both of which flank 18S rRNA, are not required. The success of this approach opens the possibility of functional analyses of ribosomes, with applications in basic research and synthetic biology.

Burman, Luke G.; Mauro, Vincent P.

2012-01-01

92

The r-process element abundance with a realistic fission fragment mass distribution  

SciTech Connect

Effect of the {beta}-delayed fission in r-process abundance is investigated with a realistic model for the fission fragment mass distribution (FFMD). The data base for the FFMD is constructed based on the two-center shell model and multi-dimensional Langevin calculation. The {beta}-decay rates including neutron emission and {beta}-delayed fission are also newly calculated with 2nd version of the the gross theory. The differences appeared in the final element abundance calculated with and without fission process, with different {beta}-delayed fission rates are demonstrated.

Chiba, S.; Koura, H.; Maruyama, T. [Advanced Science Research Center, JAEA Tokai, Naka, Ibaraki 319-1195 (Japan); Ohta, M.; Tatsuda, S. [Department of Physics, Konan University, 8-9-1 Okamoto, Kobe 658-8501 (Japan); Wada, T. [Department of Pure and Applied Physics, Kansai University, Suita, Osaka 564-8680 (Japan); Tachibana, T. [Senior High School of Waseda University, Tokyo (Japan); Sumiyoshi, K. [Numazu College of Technology, Ooka 3600, Numazu 410-8501 (Japan); Otsuki, K. [GSI Theory Department, Planckstrassel 64291 Darmstadt Germany (Germany); Kajino, T. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); University of Tokyo (Japan)

2008-05-21

93

Binaries in r-Process Enhanced Extremely Metal-Poor Stars: Chemical Tagging in the Early Galactic Halo  

NASA Astrophysics Data System (ADS)

This poster showed that the frequency and orbital properties of binaries among r-process enhanced EMP stars is normal. Thus, the r-process enhancement has nothing to do with binary evolution or mass exchange, but was imprinted preferentially on some star-forming clouds in the early ISM.

Andersen, J.; Nordström, B.; Hansen, T.; Buchhave, L.; Beers, T. C.

2012-08-01

94

r-process abundances in the EMP star CS 31082-001 using STIS/HST  

NASA Astrophysics Data System (ADS)

We present a brief revision of the origin of heavy elements and the role of abundances in extremely metal-poor (EMP) stars, in providing improved constraints on the nature of the early nucleosynthesis mechanisms. Heavy element abundances in the EMP uranium-rich star CS 31082-001 based mainly on near-UV spectra from STIS/HST are presented. With new abundances for 9 n-elements not available in previous works (Ge, Mo, Lu, Ta, W, Re, Pt, Au, and Bi) this work makes CS 31082-001 the most completely well studied r-II object, with a total of 37 detections of n-capture elements. 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.

Siqueira-Mello, C., Jr.; 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.

2012-12-01

95

Recent advances in R&D of gas cluster ion beam processes and equipment  

NASA Astrophysics Data System (ADS)

This report reviews a new field of ion beam technology that employs accelerated ions consisting of clusters of a few hundreds to thousands of atoms (Gas Cluster Ion Beam technology, GCIB). Cluster ion-surface collisions have been found to produce low energy bombardment effects at very high density and GCIB processes exhibit unique non-linear effects that are useful for novel surface processing applications. The effects include low energy ion bombardment, lateral sputtering, and low temperature thin film formation. GCIB processing has been successfully applied for shallow junction formation; for high rate etching; for surface smoothing of materials including metals, dielectrics, superconductors and diamond; and for high-k oxide and DLC thin film deposition. Currently, industrial applications of GCIB processes are being conducted by several Japanese companies under the Nanotechnology program called “Advanced Nano-Fabrication Process Technology Using Quantum Beams” of NEDO/METI (New Energy and Industrial Technology Development Organization/the Ministry of economy and Technology Industry). In US, R&D especially for semiconductor applications are under way at Epion Corporation, International SEMATEC and their cooperated associations. Epion is the only company that is developing industrial GCIB equipment and has joined the NEDO/METI project. The review includes recent equipment and process developments. In nano-scale GCIB processes, the effect of cluster size (atoms/cluster) on surface processing, especially damage production, becomes important. In the project, GCIB equipment with cluster size selection system has been developed. Several industrial applications for surface smoothing of magnetic and semiconductor materials by the Japanese government and IC processing by US companies are summarized.

Yamada, Isao; Toyoda, Noriaki

2005-12-01

96

Elucidating the Role of C\\/D snoRNA in rRNA Processing and Modification in Trypanosoma brucei  

Microsoft Academic Search

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

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

2008-01-01

97

In Search of r-Process 247Cm in the Early Solar System  

NASA Astrophysics Data System (ADS)

The r-process only nuclide 247Cm decays to 235U with a characteristic half-life of ˜16 million years. 247Cm is presently extinct, but offers considerable potential as a short-lived r-process chronometer, providing constraints on the time interval between the last r-process nucleosynthetic event and the formation of the solar system. The existence of "live" 247Cm in the early solar system should be manifested today as variations in 235U/238U, provided Cm was chemically fractionated from U when solids formed in the early solar system. The Cm-U system also has a direct bearing on the fundamental U-Pb cosmochronometer, which currently assumes no Cm effects in early solar system material. Using a Nu Instruments NuPlasma and new techniques in multiple-collector ICPMS, we are able to resolve variations in 235U/238U at the two epsilon level (2? ; 1 ? = 1 part in 10,000) on sample sizes consisting of <20 pg of 235U. The high precision of our measurements offers the potential to resolve 235U anomalies, including samples where Cm-U effects had previously been unobserved. Our first uranium isotopic measurements were acquired on bulk samples of a suite of carbonaceous chondrite, ordinary chondrite and eucrite meteorites, for which conflicting results had previously been obtained. These data show no well-resolved excursions in 235U/238U from the terrestrial value at the ˜2 epsilon level, and constrain the amount of 247Cm-produced excess 235U atoms to less than ˜1 x 108 atoms per gram of chondritic meteorite, with respect to terrestrial 235U/238U (Stirling et al., in press, Geochim. Cosmochim. Acta). We have extended the search for "live" 247Cm in the early solar system to small samples from mineral phases in primitive objects that are likely to display strong Cm-U fractionations. In particular, uranium isotopic measurements have been acquired on acid-etched leachates for a suite of chondritic meteorites, and for a suite of minerals separated from chondrites and angrites. Some of these data show resolvable excursions away from the composition of our terrestrial standard, and as such, have important implications for the 247Cm-235U cosmochronometer and the timing of r-process nucleosynthesis relative to the formation of the first solar system materials.

Stirling, C. H.; Halliday, A. N.; Potter, E.; Andersen, M. B.

2004-12-01

98

Fission fragment mass distribution for nuclei in the r-process region  

SciTech Connect

The fission fragment mass distribution is estimated theoretically on about 2000 nuclides which might have a critical role on the r-process nucleosynthesis through fission (Z>85). The mass distribution of fission fragment is derived by considering the location and the depth of valleys of potential energy surface near scission point of nuclei calculated by means of the liquid drop model with the shell energy correction by the Two-Center shell model. The guiding principle of determining the fission mass asymmetry is the behavior of the fission paths from the saddle to the scission point given by the Langevin calculation.

Tatsuda, S.; Hashizume, K.; Wada, T.; Ohta, M. [Department of Physics, Konan University, 8-9-1 Okamoto, Kobe 658-8501 (Japan); Sumiyoshi, K. [Numazu College of Technology, NAO (Japan); Otsuki, K. [Univ. of Chicago (United States); Kajino, T. [NAO, GUSA, Univ. of Tokyo (Japan); Koura, H.; Chiba, S. [JAEA (Japan); Aritomo, Y. [FLNR (JINR) (United States)

2007-02-26

99

Single Neutron Transfer Experiments Close to the r-Process Path  

SciTech Connect

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.

Grzywacz-Jones, Kate L [ORNL; Adekola, Aderemi S [ORNL; Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Chae, Kyung Yuk [ORNL; Chipps, K. [Colorado School of Mines, Golden; Cizewski, Jolie [ORNL; Dean, David Jarvis [ORNL; Erikson, Luke [Colorado School of Mines, Golden; Fitzgerald, R. P. [University of North Carolina, Chapel Hill; Gaddis, A. L. [Furman University; Greife, U. [Colorado School of Mines, Golden; Harlin, Christopher W [ORNL; Hatarik, Robert [Rutgers University; Howard, Joshua A [ORNL; Johnson, Micah [ORNL; Kozub, R. L. [Tennessee Technological University; Liang, J Felix [ORNL; Livesay, Jake [ORNL; Ma, Zhanwen [ORNL; Moazen, Brian [University of Tennessee, Knoxville (UTK); O'Malley, Patrick [Rutgers University; Nesaraja, Caroline D [ORNL; Pain, S. D. [Rutgers University; Patterson, N. P. [University of Surrey, UK; Paulauskas, Stanley V [ORNL; Shapira, Dan [ORNL; ShrinerJr., J. F. [Tennessee Technological University; Sissom, D. J. [Tennessee Technological University; Smith, Michael Scott [ORNL; Swan, T. P. [University of Surrey, UK; Thomas, J. S. [Rutgers University

2007-01-01

100

12B(n,?)-the influence on r-process nucleosynthesis of light elements  

NASA Astrophysics Data System (ADS)

Because of interest in the 11,12B(n,?) reaction in seeding r-process nucleosynthesis through light neutron-rich nuclei, we have measured the 12B(d,p) reaction for the first time using the ATLAS in-flight facility at Argonne National Laboratory. We also measured the 11B(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 12B are obtained from the current experiment and the reaction rate for 11B(n,?) is discussed in comparison with the theoretical prediction.

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

2009-03-01

101

Progress in nuclei approaching the r-process waiting point at A=195  

NASA Astrophysics Data System (ADS)

Heavy neutron-rich nuclei approaching the r-process waiting point A=195 were produced by cold-fragmentation reactions induced by 208Pb projectiles at 1 A GeV on a beryllium target at the Fragment Separator at GSI. Moreover, a new technique has been developed to measure ?- decay half-lives in complex background conditions. Around 30 heavy neutron-rich nuclei have been synthesized for the first time and the half-lives of some of them have been determined.

Kurtukian-Nieto, Teresa; Benlliure, J.; Schmidt, K.-H.; Audoin, L.; Becker, F.; Blank, B.; Cesarejos, E.; Cortina-Gil, D.; Fernandez-Ordonez, M.; Giovinazzo, J.; Henzlova, D.; Jurado, B.; Pereira, J.; Rejmund, F.; Yordanov, O.

102

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

NASA Astrophysics Data System (ADS)

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

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

2003-05-01

103

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

SciTech Connect

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.

Baruah, S.; Herlert, A.; Schweikhard, L. [Institut fuer Physik, Ernst-Moritz-Arndt-Universitaet, 17487 Greifswald (Germany); Audi, G.; Guenaut, C.; Lunney, D. [CSNSM-IN2P3-CNRS, Universite de Paris Sud, Orsay (France); Blaum, K.; George, S. [GSI, Planckstr. 1, 64291 Darmstadt (Germany); Institut fuer Physik, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany); Dworschak, M.; Herfurth, F.; Yazidjian, C. [GSI, Planckstr. 1, 64291 Darmstadt (Germany); Hager, U. [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), 40014 Jyvaeskylae (Finland); Helsinki Institute of Physics, University of Helsinki, 00014 Helsinki (Finland); Kellerbauer, A. [Physics Department, CERN, 1211 Geneva 23 (Switzerland); Kluge, H.-J. [GSI, Planckstr. 1, 64291 Darmstadt (Germany); Fakultaet fuer Physik und Astronomie, Ruprecht-Karls-Universitaet, 69120 Heidelberg (Germany); Schatz, H. [Department of Physics and Astronomy, NSCL, and JINA, Michigan State University, East Lansing, Michigan 48824 (United States)

2008-12-31

104

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

NASA Astrophysics Data System (ADS)

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

Van Schelt, Jonathon A.

105

Single Particle states in ^131,133Sn and r-process nucleosynthesis  

NASA Astrophysics Data System (ADS)

The (d,p) transfer reaction was recently used with radioactive ^130Sn and ^132Sn beams to determine four strong single-particle bound levels in ^131,133Sn. These levels have strikingly similar excitation energy spacings that have not yet been addressed by a theoretical nuclear structure model. Information on these single particle bound levels, as well as on resonant levels above the neutron capture threshold, are also needed to determine the ^130,132Sn neutron capture cross sections -- and their corresponding thermonuclear reaction rates -- which (in the case of ^130Sn) significantly impacts the synthesis of heavy elements in the r-process in supernovae. We used the analytical continuation of the coupling constant (ACCC) method based on a relativistic mean field theory with BCS approximation to self-consistently calculate single-particle bound and resonant levels for ^131,133Sn. Our results for the single particle bound and resonant levels in ^131,133Sn will be presented, along with our level densities and the implications for neutron capture cross sections for r-process studies.

Smith, Michael; Zhang, Shisheng; Kozub, Ray; Arbanas, Goran

2012-10-01

106

Elements for successful sensor-based process control {l_brace}Integrated Metrology{r_brace}  

SciTech Connect

Current productivity needs have stimulated development of alternative metrology, control, and equipment maintenance methods. Specifically, sensor applications provide the opportunity to increase productivity, tighten control, reduce scrap, and improve maintenance schedules and procedures. Past experience indicates a complete integrated solution must be provided for sensor-based control to be used successfully in production. In this paper, Integrated Metrology is proposed as the term for an integrated solution that will result in a successful application of sensors for process control. This paper defines and explores the perceived four elements of successful sensor applications: business needs, integration, components, and form. Based upon analysis of existing successful commercially available controllers, the necessary business factors have been determined to be strong, measurable industry-wide business needs whose solution is profitable and feasible. This paper examines why the key aspect of integration is the decision making process. A detailed discussion is provided of the components of most importance to sensor based control: decision-making methods, the 3R's of sensors, and connectivity. A metric for one of the R's (resolution) is proposed to allow focus on this important aspect of measurement. A form for these integrated components which synergistically partitions various aspects of control at the equipment and MES levels to efficiently achieve desired benefits is recommended.

Butler, Stephanie Watts [Texas Instruments, Silicon Technology Development, Dallas, Texas 75265 (United States)

1998-11-24

107

Nuclear deformations in the region of the A=160 r-process abundance peak  

NASA Astrophysics Data System (ADS)

In the abundance spectrum of r-process nuclei the most prominent features are the peaks that form when the r-process flow passes through the closed neutron shells. However, there are also other features in the abundance spectrum that cannot be explained by shell effects; for example, the peak in the region of the rare-earth nuclei around mass A=160. It has been argued that this peak is related to the deformation maximum of the neutron-rich isotopes. In recent years, both experimental and theoretical work has been carried out to study the deformation of neutron-rich rare-earth nuclei and to search for the point of maximum deformation. This work has focused on the nuclei around 170Dy with the aim of understanding the evolution of collectivity in the neutron shell with 82

Söderström, P.-A.

2012-10-01

108

Precision Mass Measurements of Heavy ^252Cf Fission Fragments Near the r-Process Path  

NASA Astrophysics Data System (ADS)

Precision mass measurements of species near the astrophysical r-process path are vital to reduce the uncertainties in the relevant neutron separation energies given by mass models, and the consequent abundance predictions. As part of an ongoing program, the Canadian Penning Trap mass spectrometer at Argonne National Laboratory is measuring the masses of fission products from a 150 ?Ci ^252Cf source placed inside a new large-volume He gas catcher. New precision mass measurements have been made closer to the r-process path than have previously been published, with precisions near 15 keV/c^2. Presented measurements include Pr, Nd, Pm, Sm, Eu, and Gd to N = 96, 97, 98, 99, and 99 respectively, and our results differ from the AME 2003 by up to 515 keV/c^2. Work will continue with the current fission source until 2009, when measurements of many more neutron-rich isotopes will be made at the CARIBU upgrade to the ATLAS accelerator at ANL.

van Schelt, J.; Savard, G.; Caldwell, S.; Sternberg, M.; Clark, J. A.; Greene, J. P.; Levand, A. F.; Sun, T.; Zabransky, B. J.; Fallis, J.; Sharma, K. S.; Lascar, D.; Segel, R. E.; Li, G.

2008-10-01

109

Diafiltration and water recovery of Reactive Brilliant Blue KN-R solution by two-stage membrane separation process  

Microsoft Academic Search

The conventional process of Reactive Brilliant Blue KN-R production is low purity, labor intensive, inconsistent in the production quality and also causes pollution. The improved process based on membrane technology still generates large volume of effluent though with low pollutants. In this paper, a two-stage membrane separation process is introduced to resolve these shortcomings, in which the first stage is

Yi He; Guangming Li; Hua Wang; Zhuwu Jiang; Jianfu Zhao; Hexiang Su; Qunying Huang

2010-01-01

110

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

SciTech Connect

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.

Not Available

2005-09-01

111

Abundances of Actinides and Short-lived Nonactinides in the Interstellar Medium: Diverse Supernova Sources for the r-Processes  

Microsoft Academic Search

Abundances of 244Pu, 235U, 238U, and 232Th in the early solar system are about those expected for uniform production over most of galactic history. The inferred abundance of 182Hf is also compatible with this model. We here associate production of 182Hf with the same r-process SN sources that produce actinides (SNACS). This requires that r-process nucleosynthesis in SNACS took place

G. J. Wasserburg; M. Busso; R. Gallino

1996-01-01

112

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

113

Precision Mass Measurements of Heavy ^252Cf Fission Fragments Near the Astrophysical r-Process Path  

NASA Astrophysics Data System (ADS)

Precision mass measurements of species near the path of the astrophysical r-process---expected to occur in core-collapse supernovae or neutron star mergers---are vital to reduce the uncertainties in the relevant neutron separation energies given by mass models and the consequent predictions of nucleosynthesis yields. As part of an ongoing program, the Canadian Penning Trap mass spectrometer at Argonne National Laboratory is measuring the masses of fission products from a 150 ?Ci ^252Cf source placed inside a large-volume He gas catcher. Presented measurements include Pr, Nd, Pm, Sm, Eu, and Gd to N = 96, 97, 98, 99, 98, and 99 respectively with precisions near 15 keV/c^2, and our results differ from the AME 2003 by up to 390 keV/c^2. Measurements of many more neutron-rich isotopes will be made in 2009 at the CARIBU upgrade to the ATLAS accelerator at ANL, which is approaching operation.

van Schelt, J.; Savard, G.; Caldwell, S.; Sternberg, M.; Clark, J. A.; Greene, J. P.; Levand, A. F.; Sun, T.; Zabransky, B. J.; Fallis, J.; Sharma, K. S.; Lascar, D.; Segel, R. E.; Li, G.

2009-05-01

114

An r-process Kilonova Associated with the Short-hard GRB 130603B  

NASA Astrophysics Data System (ADS)

We present ground-based optical and Hubble Space Telescope (HST) optical and near-IR observations of the short-hard GRB 130603B at z = 0.356, which demonstrate the presence of excess near-IR emission matching the expected brightness and color of an r-process powered transient (a "kilonova"). The early afterglow fades rapidly with ? <~ –2.6 at t ? 8-32 hr post-burst and has a spectral index of ? ? –1.5 (F ?vpropt ???), leading to an expected near-IR brightness at the time of the first HST observation of m F160W(t = 9.4 days) >~ 29.3 AB mag. Instead, the detected source has m F160W = 25.8 ± 0.2 AB mag, corresponding to a rest-frame absolute magnitude of MJ ? –15.2 mag. The upper limit in the HST optical observations is m F606W >~ 27.7 AB mag (3?), indicating an unusually red color of V – H >~ 1.9 mag. Comparing the observed near-IR luminosity to theoretical models of kilonovae produced by ejecta from the merger of an NS-NS or NS-BH binary, we infer an ejecta mass of M ej ? 0.03-0.08 M ? for v ej ? 0.1-0.3c. The inferred mass matches the expectations from numerical merger simulations. The presence of a kilonova provides the strongest evidence to date that short GRBs are produced by compact object mergers, and provides initial insight on the ejected mass and the primary role that compact object merger may play in the r-process. Equally important, it demonstrates that gravitational wave sources detected by Advanced LIGO/Virgo will be accompanied by optical/near-IR counterparts with unusually red colors, detectable by existing and upcoming large wide-field facilities (e.g., Pan-STARRS, DECam, Subaru, LSST).

Berger, E.; Fong, W.; Chornock, R.

2013-09-01

115

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

SciTech Connect

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.

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

2006-01-01

116

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

PubMed

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

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

2013-08-23

117

Stx5 is a novel interactor of VLDL-R to affect its intracellular trafficking and processing.  

PubMed

We identified syntaxin 5 (Stx5), a protein involved in intracellular vesicle trafficking, as a novel interaction partner of the very low density lipoprotein (VLDL)-receptor (VLDL-R), a member of the LDL-receptor family. In addition, we investigated the effect of Stx5 on VLDL-R maturation, trafficking and processing. Here, we demonstrated mutual association of both proteins using several in vitro approaches. Furthermore, we detected a special maturation phenotype of VLDL-R resulting from Stx5 overexpression. We found that Stx5 prevented advanced Golgi-maturation of VLDL-R, but did not cause accumulation of the immature protein in ER, ER to Golgi compartments, or cis-Golgi ribbon, the main expression sites of Stx5. Rather more, abundantly present Stx5 was capable of translocating ER-/N-glycosylated VLDL-R to the plasma membrane, and thus was insensitive to BFA treatment and low temperature. Furthermore, abundant presence of Stx5 significantly interfered with VLDL-R reaching the trans-Golgi network. Based on our findings, we postulate that Stx5 can directly bind to the C-terminal domain of VLDL-R, thereby influencing the receptor's glycosylation, trafficking and processing characteristics. Resulting from that, we further suggest that Stx5 might play a role in modulating VLDL-R physiology by participating in an abrasively described or completely novel Golgi-bypass pathway. PMID:23701949

Wagner, Timo; Dieckmann, Marco; Jaeger, Sebastian; Weggen, Sascha; Pietrzik, Claus U

2013-05-20

118

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

Microsoft Academic Search

Monazite sand processing was conducted at the W. R. Grace Curtis Bay Facility (Baltimore, Maryland) in the mid 1950's under contract to the Atomic Energy Commission (AEC), for the extraction of source material in the form of thorium, as well as rare earth elements. The processing was conducted in the southwest quadrant of a five-story building (Building 23) in the

N. Fatherly; M. ONeill; A. Glemza

2008-01-01

119

R-matrix approach with proper boundary conditions for dissipative and nondissipative collision processes  

SciTech Connect

We develop an R-matrix approach to treating collision processes which explicitly takes into account, by means of a simple energy-dependent analytic function, the out-of-phase oscillations of the incident and scattered standing waves in the interior region. Thereby we avoid the use of the Bloch operator. In place of the Bloch operator the incident wave provides the source term in an inhomogeneous equation for the scattered wave. We take those subchannels not treated exactly into account via the optical potential, which is generally non-Hermitian due to dissipation at the boundary. The optical potential is constructed on a real analytic basis using a resolvent that satisfies outgoing-wave boundary conditions. The use of an analytic basis together with the direct determination of the K matrix, rather than the R matrix, at the boundary (this is done by matching the interior wave function to the nearly exact analytic solution beyond the boundary) makes the method particularly well suited to the treatment of ultracold collisions. We have tested our method by applying it to one-photon single-ionization of (He1s{sup 2}) accompanied by excitation to He{sup +}(2s) or He{sup +}(2p) for photon energies above the complete breakup threshold, where the optical potential is non-Hermitian. Excellent agreement with experiment is obtained for the cross sections for photoionization to both He{sup +} (n=1) and to He{sup +} (n=2). The 2s-to-2p branching ratio is strongly influenced by both the optical potential and, at photon energies less than a few tens of eV above the breakup threshold, the nonadiabatic dipole mixing of the 2s and 2p states.

Xu Hao; Shakeshaft, Robin [Physics Department, University of Southern California, Los Angeles, California 90089-0484 (United States)

2011-01-15

120

RNase MRP is required for entry of 35S precursor rRNA into the canonical processing pathway  

PubMed Central

RNase MRP is a nucleolar RNA–protein enzyme that participates in the processing of rRNA during ribosome biogenesis. Previous experiments suggested that RNase MRP makes a nonessential cleavage in the first internal transcribed spacer. Here we report experiments with new temperature-sensitive RNase MRP mutants in Saccharomyces cerevisiae that show that the abundance of all early intermediates in the processing pathway is severely reduced upon inactivation of RNase MRP. Transcription of rRNA continues unabated as determined by RNA polymerase run-on transcription, but the precursor rRNA transcript does not accumulate, and appears to be unstable. Taken together, these observations suggest that inactivation of RNase MRP blocks cleavage at sites A0, A1, A2, and A3, which in turn, prevents precursor rRNA from entering the canonical processing pathway (35S > 20S + 27S > 18S + 25S + 5.8S rRNA). Nevertheless, at least some cleavage at the processing site in the second internal transcribed spacer takes place to form an unusual 24S intermediate, suggesting that cleavage at C2 is not blocked. Furthermore, the long form of 5.8S rRNA is made in the absence of RNase MRP activity, but only in the presence of Xrn1p (exonuclease 1), an enzyme not required for the canonical pathway. We conclude that RNase MRP is a key enzyme for initiating the canonical processing of precursor rRNA transcripts, but alternative pathway(s) might provide a backup for production of small amounts of rRNA.

Lindahl, Lasse; Bommankanti, Ananth; Li, Xing; Hayden, Lauren; Jones, Adrienne; Khan, Miriam; Oni, Tolulope; Zengel, Janice M.

2009-01-01

121

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

NASA Astrophysics Data System (ADS)

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 ? 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

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

2013-10-01

122

Regulation of miR-17-92a cluster processing by the microRNA binding protein SND1.  

PubMed

MicroRNAs are small non-coding RNAs that regulate gene expression. Although all seven members of the miR-17-92a cluster originate from one primary transcript they are differentially expressed suggesting the presence of posttranscriptional regulation. By RNA pulldown and mass spectrometry we identified SND1, a known regulator of edited RNAs, interacting with pre-miR-92a and all mature miR-17-92a members. Hypoxic conditions lead to an elevation of the pri-miR-17-92a transcript and significantly increased levels of the precursors whereas the mature miRs were not significantly changed. SND1 silencing resolved this block in processing and induced an increase in mature miRs. Together, SND1 might be the missing link between hypoxia and the differential regulation of miRNA processing. PMID:23770094

Heinrich, Eva-Marie; Wagner, Jasmin; Krüger, Marcus; John, David; Uchida, Shizuka; Weigand, Julia E; Suess, Beatrix; Dimmeler, Stefanie

2013-06-13

123

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

SciTech Connect

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.

Roederer, Ian U. [Carnegie Observatories, Pasadena, CA 91101 (United States); Lawler, James E., E-mail: iur@obs.carnegiescience.edu, E-mail: jelawler@wisc.edu [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)

2012-05-01

124

Detection of Elements at All Three r-process Peaks in the Metal-poor Star HD 160617  

NASA Astrophysics Data System (ADS)

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. This research has made use of the Keck Observatory Archive (KOA), which is operated by the W.M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration. These data are associated with Program H6aH (PI: Boesgaard).

Roederer, Ian U.; Lawler, James E.

2012-05-01

125

The Complexity of Human Ribosome Biogenesis Revealed by Systematic Nucleolar Screening of Pre-rRNA Processing Factors.  

PubMed

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

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

2013-08-22

126

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

Microsoft Academic Search

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,

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

2005-01-01

127

Effect of hot-rolling processing on texture and r-value of annealed dual-phase steels  

Microsoft Academic Search

For this study, both conventional and a low-temperature hot-rolling (LTHR) processes were applied to capture the effect of hot-rolling processing conditions on the texture and r-value of annealed dual-phase (DP) steels. The LTHR process induced distinct texture gradients through the thickness direction of the hot-rolled DP steel. Microtexture analysis revealed that weakness of the ?-fiber texture in the surface and

Seong-Ho Han; Shi-Hoon Choi; Jae-Kwon Choi; Hwan-Goo Seong; In-Bae Kim

2010-01-01

128

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

SciTech Connect

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.

Ouyed, Rachid [Department of Physics and Astronomy, University of Calgary, Calgary, AB T2N 1N4 (Canada); Pudritz, Ralph E. [Origins Institute, ABB 241, McMaster University, Hamilton, ON L8S 4M1 (Canada); Jaikumar, Prashanth [Institute of Mathematical Sciences, CIT Campus, Chennai, Tamil Nadu 600013 (India)], E-mail: ouyed@phas.ucalgary.ca

2009-09-10

129

Mass Measurements of Heavy ^252Cf Fission Fragments Near the r-Process Path with the Canadian Penning Trap  

NASA Astrophysics Data System (ADS)

Precision mass measurements of nuclides near the astrophysical r-process path are vital to reduce the uncertainties in the relevant neutron separation energies and the consequent abundance predictions. Before moving to CARIBU, the Canadian Penning Trap mass spectrometer at Argonne National Laboratory undertook a series of mass measurements of spontaneous fission products from a 150 ?Ci ^252Cf source in a previous large-volume gas catcher. Masses of 38 neutron-rich nuclides ranging from Z=51 to 64 were measured, many of which were closer to the r-process path than had previously been measured for these elements. Systematic deviations from the AME 2003 are seen over a wide range of elements, and possible effects of these deviations on the r process will be discussed. These measurements are being extended to even higher neutron excess at CARIBU. )

van Schelt, J.; Lascar, D.; Savard, G.; Clark, J. A.; Greene, J. P.; Levand, A. F.; Sun, T.; Zabransky, B. J.; Caldwell, S.; Sternberg, M.; Fallis, J.; Sharma, K. S.; Segel, R. E.; Li, G.

2010-02-01

130

A hierarchical model for the galactic chemical evolution and r-process elements of extremely metal-poor stars  

NASA Astrophysics Data System (ADS)

Extremely metal-poor (EMP) stars are cosmic stellar relics in the Milky Way halo. We investigate their formation history and elemental abundances using a hierarchical chemical evolution model. We focus on the r-process elements in this study. We show that distribution of the rprocess element abundances of EMP stars are well reproduced by our hierarchical model. Electron capture supernovae of which progenitor mass is 8 - 10Msolar thought to be dominant source of rprocess elements. We also show that surface pollution by accretion of interstellar matter significantly changes the surface r-process element abundance of EMP stars.

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

2012-09-01

131

Structure And Decay Of Neutron-Rich Nuclides In The 115 {<=} A {<=} 138 Mass Range And r-Process Nucleosynthesis  

SciTech Connect

The structure and decay of neutron-rich r-process nuclides has been studied by a variety of means that take advantage of enhanced selectivity to permit identification of exotic nuclides. New level structures are presented for 134,135Sb along with data for Ag isomers and Cd yrast structures. Some of the properties measured play an important role in calculations of the yields of elements and isotopes produced in r-process nucleosynthesis that takes place at high temperature in the presence of large densities of neutrons.

Walters, W.B.; Stoyer, M.A.; Shergur, J.; Hoteling, N.; Ressler, J.J.; Rikovska, J. [University of Maryland, College Park, MD 20742 (United States); Kratz, K.-L.; Woehr, A.; Pfeiffer, B.; Arndt, O. [Institute fuer Kernchemie, Univesitaet Mainz, 55099 Mainz (Germany); Mantica, P.F.; Tomlin, B.; Schatz, H.; Montes, F.; Brown, B.A. [NSCL, Michigan State University, East Lansing, MI 48824 (United States); Seweryniak, D. [Physics Division, Argonne National Laboratory, Argonne IL 60439 (United States); Ravn, H.; Fedoseyev, V.; Koester, U. [ISOLDE, CERN, Geneva (Switzerland); Wu, C.Y. [University of Rochester, Rochester, NY 14627 (United States)] [and others

2005-04-05

132

Role of Escherichia coli YbeY, a highly conserved protein, in rRNA processing  

PubMed Central

The UPF0054 protein family is highly conserved with homologs present in nearly every sequenced bacterium. In some bacteria, the respective gene is essential, while in others its loss results in a highly pleiotropic phenotype. Despite detailed structural studies, a cellular role for this protein family has remained unknown. We report here that deletion of the Escherichia coli homolog, YbeY, causes striking defects that affect ribosome activity, translational fidelity and ribosome assembly. Mapping of 16S, 23S and 5S rRNA termini reveals that YbeY influences the maturation of all three rRNAs, with a particularly strong effect on maturation at both the 5?- and 3?-ends of 16S rRNA as well as maturation of the 5?-termini of 23S and 5S rRNAs. Furthermore, we demonstrate strong genetic interactions between ybeY and rnc (encoding RNase III), ybeY and rnr (encoding RNase R), and ybeY and pnp (encoding PNPase), further suggesting a role for YbeY in rRNA maturation. Mutation of highly conserved amino acids in YbeY, allowed the identification of two residues (H114, R59) that were found to have a significant effect in vivo. We discuss the implications of these findings for rRNA maturation and ribosome assembly in bacteria.

Davies, Bryan W.; Kohrer, Caroline; Jacob, Asha I.; Simmons, Lyle A.; Zhu, Jianyu; Aleman, Lourdes M.; RajBhandary, Uttam L.; Walker, Graham C.

2010-01-01

133

Mouse Eri1 interacts with the ribosome and catalyzes 5.8S rRNA processing  

PubMed Central

Eri1 is a 3?-to-5? exoribonuclease conserved from fission yeast to humans. Here we show that Eri1 associates with ribosomes and ribosomal RNA (rRNA). Ribosomes from Eri1– deficient mice contain 5.8S rRNA that is aberrantly extended at its 3? end, and Eri1, but not a catalytically inactive mutant, converts this abnormal 5.8S rRNA to the wild-type form in vitro and in cells. In human and murine cells, Eri1 localizes to the cytoplasm and nucleus, with enrichment in the nucleolus, the site of preribosome biogenesis. RNA binding residues in the Eri1 SAP and linker domains promote stable association with rRNA and thereby facilitate 5.8S rRNA 3? end processing. Taken together, our findings indicate that Eri1 catalyzes the final trimming step in 5.8S rRNA processing, functionally and spatially connecting this regulator of RNAi with the basal translation machinery.

Ansel, K Mark; Pastor, William A; Rath, Nicola; Lapan, Ariya D; Glasmacher, Elke; Wolf, Christine; Smith, Laura C; Papadopoulou, Nikoletta; Lamperti, Edward D; Tahiliani, Mamta; Ellwart, Joachim W; Shi, Yujiang; Kremmer, Elisabeth; Rao, Anjana; Heissmeyer, Vigo

2011-01-01

134

Role of the ITS2-proximal stem and evidence for indirect recognition of processing sites in pre-rRNA processing in yeast  

PubMed Central

Eucaryotic ribosome biogenesis involves many cis-acting sequences and trans-acting factors, including snoRNAs. We have used directed mutagenesis of rDNA plasmids in yeast to identify critical sequence and structural elements within and flanking the ITS2-proximal stem. This base paired structure, present in the mature ribosome, is formed between the 5?-end of 25S and the 3?-end of 5.8S rRNAs. Previously we demonstrated that formation of this structure was critical for pre-rRNA processing in yeast. Here we show that there are no sequence-specific recognition elements within the ITS2-proximal stem, rather the structure of this stem is critical for processing. This stem cannot exceed a specific length, but there are different length restrictions for different regions within this tripartite stem. Neither the conserved unpaired nucleotides within the stem nor the sequence of the mature rRNA at the processing sites are required for processing. Collectively, these results suggest a measuring model whereby initial cleavage within ITS2 at the C2 processing site and termination of subsequent exonuclease activity yielding the mature termini are affected by the relative position of sequence and structural elements within the ITS2-proximal stem.

Cote, Colette A.; Peculis, Brenda A.

2001-01-01

135

s- and r-Process Element Abundances in the CMD of 47 Tucanæ Using the Robert Stobie Spectrograph on SALT*  

NASA Astrophysics Data System (ADS)

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

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

136

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

NASA Astrophysics Data System (ADS)

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: ?-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.

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

137

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)

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.

Liu, Pang-Lo; Tsai, Chih-Hung

138

A low initial abundance of 247Cm in the early solar system and implications for r-process nucleosynthesis  

NASA Astrophysics Data System (ADS)

The short-lived nuclide 247Cm is produced by r-process nucleosynthesis. When the presolar nebula formed, 247Cm became isolated from r-process production and its abundance diminished as a result of radioactive decay. Given its short half-life of only ˜ 16 million years, 247Cm is presently extinct, but its former presence should be detectable as small variations in 235U/238U in primitive meteoritic material, provided Cm was chemically fractionated from U at the time these solid objects formed. The magnitude of U isotopic anomalies in meteorites can thus be used to elucidate the timing and character of the last r-process nucleosynthetic event for input into models describing the formation and evolution of the early solar system. Here we report coupled U isotopic determinations and Nd/U proxy measurements for Cm/U in a series of acid-etched leachates and mineral assemblages extracted from meteorites containing primitive phases expected to show strong Cm U fractionations. Using multiple-collector ICPMS, we are able to determine 235U/238U with 2? analytical uncertainties of ± 1 epsilon (1 epsilon = 1 part in 10,000) on sample sizes consisting of < 3 ng of 238U and < 20 pg of 235U. A double-spiking procedure using a mixed 236U 233U spike was employed to allow instrumental mass fractionation to be reliably corrected internally and at high precision. Uranium isotopic results for almost 40 different phases show no resolvable deviations in 235U/238U from the chondritic value, at the ˜ 1 2 epsilon level. These data supplement our previous observations for a suite of bulk meteorite samples [C.H. Stirling, A.N. Halliday, D. Porcelli, In search of live 247Cm in the early solar system, Geochim. Cosmochim. Acta 69 (2005) 1059 1071] and provide evidence for a solar system initial 247Cm/235U of < 8 × 10- 5. Such a low value is difficult to explain without a long time-scale of ˜ 2.3 × 108 years between the last actinide producing r-process event and the formation of the solar system. As such it is difficult to reconcile with a model of actinide production in the same r-process forming event as 182Hf with a half-life of 8.9 My [G.J. Wasserburg, M. Busso, R. Gallino, Abundances of actinides and short-lived nonactinides in the interstellar medium: Diverse supernova sources for the r-processes, Astrophys. J. 466 (1996) L109 L113]. The alternative models of 182Hf production via a neutron-rich fast s-process, occurring, for example, in the helium burning shell in a 25 solar mass star during explosive nucleosynthesis [G.J. Wasserburg, M. Busso, R. Gallino, Abundances of actinides and short-lived nonactinides in the interstellar medium: Diverse supernova sources for the r-processes, Astrophys. J. 466 (1996) L109 L113], or via a distinct r-process event that is separate from actinide production [G.J. Wasserburg, M. Busso, R. Gallino, K.M. Nollet, Short-lived nuclei in the early solar system: Possible AGB sources, Nucl. Phys. A (in press)], may provide a viable explanation. However, further studies are also required to assess the veracity of Cm U systematics, which are critically dependent on the suitability of using Nd and the light rare earth elements (LREEs) as a chemical proxy for Cm.

Stirling, Claudine H.; Halliday, Alex N.; Potter, Emma-Kate; Andersen, Morten B.; Zanda, Brigitte

2006-11-01

139

Neutrino-induced nucleosynthesis in supernovae: synthesis of light elements and neutrino-driven r-process  

NASA Astrophysics Data System (ADS)

We report the results of our neutrino nucleosynthesis project that concern the neutrino-induced production of light and heavy elements in the helium shell of poor metal core collapse supernovae. The outer half of the helium shell is shown to be a good site to obtain the neutrino-driven weak component of the r-process up to A ? 130 and simultaneously to produce significant yields of the light elements such as 7Li and 11B. Special attention is given to an old idea that by means of the activation by shock heating reaction 13C(?, n)16O an enhanced amount of 13C in the helium shell could be an additional source of neutrons for the r-process. The main conclusion is that both the neutrino and 13C neutron sources can contribute to the r-process only for poor metal stars, the latter being active for rather strong explosions of energy gsim3 × 1051 erg. Contrary to the light elements, the r-process yields are strongly sensitive to the admixture of the neutron poisons such as 12C, 14N and 16O.

Nadyozhin, D. K.; Panov, I. V.

2008-01-01

140

The influence of rTMS over the right dorsolateral prefrontal cortex on top-down attentional processes  

Microsoft Academic Search

Repetitive Transcranial Magnetic Stimulation (rTMS) provides a unique opportunity to study causal relationships between activity in the dorsolateral prefrontal cortex (DLPFC) and executive functioning, by modulating brain activity in SHAM controlled designs. We devised a new Stroop task paradigm in which subjects must engage in both strategic and automatic attentional processes. In the current experiment, we manipulated subjects' expectancies for

Marie-Anne Vanderhasselt; Rudi De Raedt; Chris Baeken; Lemke Leyman; Peter Clerinx; Hugo D'haenen

2007-01-01

141

Investigation of very neutron-rich Fe, Co and Ni isotopes encountered along the r-process path.  

National Technical Information Service (NTIS)

Very neutron-rich nuclei beyond Fe must be investigated in order to understand the r-process. New Ni, Co and Fe isotopes, with ten to twelve neutrons more than the heaviest stable isotopes, were discovered in the thermal fission of (sup 235)U and (sup 239...

S. Czajkowski M. Bernas J. L. Sida P. Armbruster H. Faust

1992-01-01

142

Analysis and Summary of Business Processes and Requirements for JIFFY R & D Program Management Software Capabilities.  

National Technical Information Service (NTIS)

This document describes the methodology and requirements for a subset of the functionality of the JIFFY R&D Program Management software, scheduled for deployment at the Air Force Research Laboratory (AFRL) in September 2003. The incorporation of new capab...

J. D. Smith

2004-01-01

143

Beyond the Knowledge Production Function: The Role of R+D in a Multifaceted Innovative Process  

Microsoft Academic Search

The purpose of this paper is to test the possible catalysing role of in-house R+D in fostering the complementarity of innovative inputs on a sample of 3045 manufacturing firms drawn from the third Italian Community Innovation Survey (1998-2000). The interactions between four different sources of innovation - internal and external R+D, embodied and disembodied technological acquisitions - have been simultaneously

Alessandra Catozzella; Marco Vivarelli

2007-01-01

144

Dynamic conformational model for the role of ITS2 in pre-rRNA processing in yeast.  

PubMed Central

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.

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

2002-01-01

145

Comparing the after-effects of continuous theta burst stimulation and conventional 1 Hz rTMS on semantic processing.  

PubMed

Our aim was to evaluate continuous theta burst stimulation (cTBS) as a tool to induce temporary impairment (virtual lesion) in semantic processing. Four groups with 20 subjects each were stimulated. In the three experimental groups the stimulation site was the left superior temporal cortex. Stimulation was either 1Hz repetitive transcranial magnetic stimulation (rTMS) at 100% resting motor threshold (RMT) or cTBS, with intensities of 80% or 90% active motor threshold (AMT). The TMS-control group was stimulated at the right medial prefrontal cortex with 1 Hz rTMS. After stimulation subjects accomplished a lexical decision task with a duration of about 20 min. In an additional fifth group the lexical decision task was performed without TMS. Reaction times were not influenced by cTBS applied with 80% AMT, but prolonged for about 80 ms with 90% AMT compared to the no stimulation condition. An increase of 140 ms was found after 1 Hz rTMS. The effect lasted for the whole task, but declined from the first to the second half of the experiment. The direct comparison of cTBS and 1 Hz rTMS suggests that both stimulation patterns can induce virtual lesions in the left superior temporal cortex and impair semantic processing. We suppose that cTBS could replace 1 Hz rTMS in this field since the application is faster and it is more comfortable to the subjects. PMID:23276670

Brückner, S; Kiefer, M; Kammer, T

2012-12-29

146

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

147

Reexamining the temperature and neutron density conditions for r-process nucleosynthesis with augmented nuclear mass models  

NASA Astrophysics Data System (ADS)

We explore the effects of nuclear masses on the temperature and neutron density conditions required for r-process nucleosynthesis using four nuclear mass models augmented by the latest atomic mass evaluation. For each model we derive the conditions for producing the observed abundance peaks at mass numbers A˜80, 130, and 195 under the waiting-point approximation and further determine the sets of conditions that can best reproduce the r-process abundance patterns (r-patterns) inferred for the solar system and observed in metal-poor stars of the Milky Way halo. In broad agreement with previous studies, we find that (1) the conditions for producing abundance peaks at A˜80 and 195 tend to be very different, which suggests that, at least for some nuclear mass models, these two peaks are not produced simultaneously; (2) the typical conditions required by the critical waiting-point (CWP) nuclei with the N=126 closed neutron shell overlap significantly with those required by the N=82 CWP nuclei, which enables coproduction of abundance peaks at A˜130 and 195 in accordance with observations of many metal-poor stars; and (3) the typical conditions required by the N=82 CWP nuclei can reproduce the r-pattern observed in the metal-poor star HD 122563, which differs greatly from the solar r-pattern. We also examine how nuclear mass uncertainties affect the conditions required for the r-process and identify some key nuclei including 76Ni to 78Ni, 82Zn, 131Cd, and 132Cd for precise mass measurements at rare-isotope beam facilities.

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

2013-01-01

148

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

149

Quasiclassical R -matrix theory of inelastic processes in collisions of electrons with HCl molecules  

SciTech Connect

The {ital R}-matrix theory for the vibrational excitation and dissociative attachment in {ital e}-HCl collisions is developed. Only one pole in the {ital R}-matrix expansion is included. This allows for making a connection between the {ital R}-matrix and the nonlocal-complex-potential theories, and for obtaining the expression for the dissociative-attachment cross section without using the {ital R}-matrix radius in the internuclear coordinate. All matrix elements in the equation for the vibrational-excitation and dissociative-attachment amplitudes are calculated using the quasiclassical approach. We study how the results depend on the number of vibrational levels of the neutral molecule included in the theory and show how to exclude the vibrational continuum by a modification of the nonlocal-complex potential. The results for the vibrational-excitation cross sections are extremely sensitive to the behavior of the {ital R}-matrix potential curve near the point of crossing this curve with the potential curve of the neutral molecule. Particularly in some cases the cross section at the threshold peak exhibits the boomerang oscillations earlier found for HCl by Domcke (in {ital Aspects} {ital of} {ital Electron}{minus}{ital Molecule} {ital Scattering} {ital and} {ital Photoionization}, edited by A. Herzenberg (AIP, New Haven, 1989), p. 169). The dissociative-attachment cross sections are in reasonable agreement with experiment and with other theories.

Fabrikant, I.I. (Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0111 (US))

1991-04-01

150

Photocatalytic degradation of Reactive Brilliant Blue KN-R by TiO 2\\/UV process  

Microsoft Academic Search

The photocatalytic degradation of Reactive Brilliant Blue KN-R has been investigated under UV irradiation in aqueous suspension of titanium dioxide under a variety of conditions. The degradation was studied by monitoring the change in dye concentration using UV spectroscopic technique. The effects of key operation parameters such as initial dye concentration, catalyst loading, hydrogen peroxide dosage as well as initial

Yumin Liu; Lv Hua; Shuangqing Li

2010-01-01

151

R&D project termination decisions: Processes, communication, and personnel changes  

Microsoft Academic Search

The decision to terminate a project can demoralize project managers and team members, and increase concerns about job security. For these reasons, managers tend to delay project termination decisions. However, delaying project termination diverts scarce R&D resources from higher potential projects.Ramaiya Balachandra, Klaus K. Brockhoff, and Alan W. Pearson describe the results of a study that explores the manner in

R. Balachandra; Klaus K. Brockhoff; Alan W. Pearson

1996-01-01

152

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

NASA Astrophysics Data System (ADS)

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-rich elements of 90 < A < 160. We confirm the primary synthesis of light p-elements in the ejected matter of high peak temperature. The ejected matter has [Sr/Eu] ˜ -0.4, which is different from that of a typical r-process-enriched star CS22892-052 ([Sr/Eu] ˜ -1). We find that Sr-Y-Zr isotopes are primarily synthesized in the explosive nucleosynthesis in a similar process of the primary production of light p-elements, which has been considered as one of the sites of a lighter element primary process (LEPP).

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

2012-10-01

153

Search for spin-orbit-force reduction at 106,108Zr around r-process path  

NASA Astrophysics Data System (ADS)

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 N = 70 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, 110Zr(Z = 40,N = 70). We performed ?-? and isomer spectroscopy at RIBF to observe low-lying states in 106,108Zr. The present results indicate a well deformed shape for 106,108Zr. The drastic reduction of the spin-orbit force most likely does not occur around 110Zr on an r-process path.

Sumikama, T.; Yoshinaga, K.; Watanabe, H.; Nishimura, S.; Miyashita, Y.; Yamaguchi, K.; Sugimoto, K.; Chiba, J.; Li, Z.; Baba, H.; Berryman, J. S.; Blasi, N.; Bracco, A.; Camera, F.; Doornenbal, P.; Go, S.; Hashimoto, T.; Hayakawa, S.; Hinke, C.; Ideguchi, E.; Isobe, T.; Ito, Y.; Jenkins, D. G.; Kawada, Y.; Kobayashi, N.; Kondo, Y.; Krücken, R.; Kubono, S.; Lorusso, G.; Nakano, T.; Kurata-Nishimura, M.; Odahara, A.; Ong, H. J.; Ota, S.; Podolyák, Zs.; Sakurai, H.; Scheit, H.; Steiger, K.; Steppenbeck, D.; Takano, S.; Takashima, A.; Tajiri, K.; Teranishi, T.; Wakabayashi, Y.; Walker, P. M.; Wieland, O.; Yamaguchi, H.

2012-11-01

154

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

SciTech Connect

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.

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

2005-02-01

155

Heavy elements in globular clusters and dwarf galaxies as probes of the origin of r-process elements  

NASA Astrophysics Data System (ADS)

Chemical abundances of very metal-poor stars record the nucleosynthesis products in the early Galaxy. Previous observational studies have revealed that the r-process is the dominant source of neutron-capture elements in extremely metal-poor stars, but the total amount of neutron-capture elements relative to lighter elements (e.g. Fe) shows large star-to-star scatter. These features are key to understanding the astrophysical sites of the r-process as well as the formation of stellar systems including extremely metal-poor stars. Such abundance studies for neutron-capture elements have been extended to metal-poor stars in globular clusters and dwarf galaxies around the Milky Way, in addition to field halo stars. We investigated the abundance ratios of neutron-capture elements for an extremely metal-poor star in the Sextans dwarf galaxy for which a significant excess of Ba was detected by a previous study, and found that the origin of heavy elements in this object is the sprocess. Although the sample size is still small, no r-process enhanced star has been found in dwarf galaxies at such low metallicity, in contrast to the Galactic halo. From ourmeasurements of neutroncapture elements in three very metal-poor globular clusters, we confirmed star-to-star scatter of Eu abundance ratios in M15, but found that these clusters are almost homogeneously enriched in lighter neutron-capture elements.

Honda, Satoshi; Aoki, Wako; Arimoto, Nobuo; Sadakane, Kozo; Otsuki, Kaori; Kajino, Toshitaka; Mathews, Grant J.

2012-11-01

156

The r-Process in the Neutrino Winds of Core-Collapse Supernovae and U-Th Cosmochronology  

NASA Astrophysics Data System (ADS)

The discovery of the second highly r-process-enhanced, extremely metal poor star, CS 31082-001 ([Fe/H]=-2.9) has provided a powerful new tool for age determination by virtue of the detection and measurement of the radioactive species uranium and thorium. Because the half-life of 238U is one-third that of 232Th, the U-Th pair can, in principle, provide a far more precise cosmochronometer than the Th-Eu pair that has been used in previous investigations. In the application of this chronometer, the age of (the progenitor of) CS 31082-001 can be regarded as the minimum age of the Galaxy, and hence of the universe. One of the serious limitations of this approach, however, is that predictions of the production ratio of U and Th have not been made in the context of a realistic astrophysical model of the r-process. We have endeavored to produce such a model, based on the ``neutrino winds'' that are expected to arise from the nascent neutron star of a core-collapse supernova. In this model, the proto-neutron star mass and the (asymptotic) neutrino sphere radius are assumed to be 2.0 Msolar and 10 km, respectively. Recent hydrodynamic studies indicate that there may exist difficulties in obtaining such a compact (massive and/or small in radius) remnant. Nevertheless, we utilize this set of parameter choices since previous work suggests that the third r-process peak (and thus U and Th) is hardly reached when one adopts a less compact proto-neutron star in the framework of the neutrino-wind scenario. The temperature and density histories of the material involved in the neutron-capture processes are obtained with the assumption of a steady flow of the neutrino-powered winds, with general relativistic effects taken into account. The electron fraction is taken to be a free parameter, constant with time. The r-process nucleosynthesis in these trajectories is calculated with a nuclear reaction network code including actinides up to Z=100. The mass-integrated r-process yields, obtained by assuming a simple time evolution of the neutrino luminosity, are compared to the available spectroscopic elemental abundance data of CS 31082-001. As a result, the ``age'' of this star is determined to be 14.1+/-2.5 Gyr, in excellent agreement with lower limits on the age of the universe estimated by other dating techniques, as well as with other stellar radioactive age estimates. Future measurements of Pt and Pb in this star, as well as expansion of searches for additional r-process-enhanced, metal-poor stars (especially those in which both U and Th are measurable), are of special importance to constrain the current astrophysical models for the r-process.

Wanajo, Shinya; Itoh, Naoki; Ishimaru, Yuhri; Nozawa, Satoshi; Beers, Timothy C.

2002-10-01

157

Processing and optimization of multiway spatial joins using R-trees  

Microsoft Academic Search

Abstract: One of the most important types of query processing in spatialdatabases and geographic information systems is the spatial join,an operation that selects, from two relations, all object pairssatisfying some spatial predicate. A multiway join combines dataoriginated from more than two relations. Although severaltechniques have been proposed for pairwise spatial joins, onlylimited work has focused on multiway spatial join processing.This

Dimitris Papadias; Nikos Mamoulis; Yannis Theodoridis

1999-01-01

158

DD3R zeolite membranes in separation and catalytic processes: Modelling and application  

Microsoft Academic Search

Around 2004 the annual energy consumption of the Dutch (petro-)chemical industry was estimated to be 460 PJ of which 200 PJ could be allocated to separation processes [1]. In 2009, 15% of the global energy consumption was required for separation and purification processes to produce commodities. Moreover, it is expected that in 2040 the global commodity demand is three times

J. Van den Bergh

2010-01-01

159

Chromatin Diminution Process Regulates rRNA Gene Copy Number in Freshwater Copepods.  

PubMed

The results of quantitative PCR (qPCR) presented in the paper clearly demonstrate that the sixteen-fold genome reduction inCyclops kolensisduring chromatin diminution (from 15.3 pg to 0.98 pg) results in a dramatic decrease in ribosomal RNA gene copy numbers in the genome of a somatic cell line by more than two orders of magnitude. The results presented allow for the consideration of the chromatin diminution as a mechanism of rDNA copy number regulation. PMID:22649664

Zagoskin, M V; Marshak, T L; Mukha, D V; Grishanin, A K

2010-10-01

160

Chromatin Diminution Process Regulates rRNA Gene Copy Number in Freshwater Copepods  

PubMed Central

The results of quantitative PCR (qPCR) presented in the paper clearly demonstrate that the sixteen-fold genome reduction inCyclops kolensisduring chromatin diminution (from 15.3 pg to 0.98 pg) results in a dramatic decrease in ribosomal RNA gene copy numbers in the genome of a somatic cell line by more than two orders of magnitude. The results presented allow for the consideration of the chromatin diminution as a mechanism of rDNA copy number regulation.

Zagoskin, M. V.; Marshak, T. L.; Mukha, D. V.; Grishanin, A. K.

2010-01-01

161

Hydrogen Technology Validation as a "Learning Demonstration" that Feeds the R&D Process (Presentation)  

SciTech Connect

This presentation, which provides information about how hydrogen technology validation is used as a learning demonstration that feeds the research and development process, was given at a National Hydrogen Association meeting in April 2004.

Wipke, K.; Gronich, S.; Hooker, D.

2004-04-01

162

Formation of the rare-earth peak: Gaining insight into late-time r-process dynamics  

NASA Astrophysics Data System (ADS)

We study the formation and final structure of the rare-earth peak (A˜160) of the r-process nucleosynthesis. Under high-entropy conditions (S>100kB), the rare-earth peak forms at late times in the r-process after neutron exhaustion (neutron-to-seed ratio R=1) as matter decays back to stability. Since rare-earth peak formation does not occur during (n,?)?(?,n) equilibrium it is sensitive to the strong interplay between late-time thermodynamic evolution and nuclear physics input. Depending on the conditions, the peak forms either because of the pattern of the neutron capture rates or because of the pattern of the separation energies. We analyze three nuclear data sets under different thermodynamic conditions. We find that the subtleties of each nuclear data set, including separation energies and neutron capture rates, influence not only the final shape of the peak but also when it forms. We identify the range of nuclei which are influential in rare-earth peak formation.

Mumpower, Matthew R.; McLaughlin, G. C.; Surman, Rebecca

2012-04-01

163

Synthetic lethality with fibrillarin identifies NOP77p, a nucleolar protein required for pre-rRNA processing and modification.  

PubMed Central

The nucleolar protein fibrillarin (encoded by the NOP1 gene in yeast), is required for many post-transcriptional steps in yeast ribosome synthesis. A screen for mutations showing synthetic lethality with a temperature sensitive nop1-5 allele led to the identification of the NOP77 gene. NOP77 is essential for viability and encodes a nucleolar protein with a predicted molecular weight of 77 kDa. Depletion of NOP77p impairs both the processing and methylation of the pre-rRNA. The processing defect is greatest for the pathway leading to 25S rRNA synthesis, and is distinctly different from that observed for mutations in other nucleolar components. NOP77p contains three canonical RNA recognition motifs (RRMs), suggesting that it is an RNA binding protein. The NOP77 allele which complements the synthetic lethal nop1 strains has an alanine at position 308, predicted to lie in helix alpha 1 of RRM3, whereas the non-complementing nop77-1 allele contains a proline at the corresponding position. We propose that NOP77p mediates specific interactions between NOP1p and the pre-rRNA. Images

Berges, T; Petfalski, E; Tollervey, D; Hurt, E C

1994-01-01

164

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

SciTech Connect

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.

Daniels, E.J.

1994-05-01

165

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

SciTech Connect

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.

Valerie Bookwalter; Bonnie Madre; Charles Reece

2008-02-12

166

A 21st Century HPLC Workflow for Process R&D  

Microsoft Academic Search

A unique high-performance liquid chromatographic (HPLC) workflow specifically designed for the rigors of process development has been developed. A key feature of the workflow is the creation of an HPLC software-hardware platform designed to automatically and systematically screen samples using a matrix of columns and eluents to aggressively search for impurities. The workflow platform was assembled from commercial hardware components

Brent D. Karcher; Merrill L. Davies; Edward J. Delaney; John J. Venit

2005-01-01

167

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

Microsoft Academic Search

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

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

2008-01-01

168

Strategic planning process-employee empowerment in an R&D center  

Microsoft Academic Search

Summary form only given, as follows. The authors discuss the strategic planning process within a basic research and development organization, NASA's Langley Research Center. With over six years' experience in developing and refining strategic plans by the Center's senior staff, the operational framework was in place to initiate a major employee empowerment activity. As a result of an agency culture

S. F. Pauls; W. L. Williams

1991-01-01

169

Half-Life Measurement for the rp -Process Waiting Point Nuclide Z{sup 80}r  

SciTech Connect

X-ray bursts have been suggested as a possible site for the astrophysical rp -process. The time scale for the process is governed by {beta} -decay half-lives of several even-even N=Z waiting point nuclei, in particular, N=Z=40 {sup 80}Zr . A 4.1(+0.8-0.6)- s {beta}{sup +}/EC half-life for {sup 80}Zr was determined by observing delayed 84-keV {gamma} rays depopulating a T{sub 1/2}=4-{mu}s isomer at 312 keV in the daughter {sup 80}Y . As this half-life is lower than many previously predicted values, the calculated excessive production of A=80 nuclides in astrophysical x-ray burst scenarios is reduced, and less extreme conditions are necessary for the production of heavier nuclides. (c) 2000 The American Physical Society.

Ressler, J. J. [Department of Chemistry, University of Maryland, College Park, Maryland 20742 (United States); Piechaczek, A. [Department of Physics, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Walters, W. B. [Department of Chemistry, University of Maryland, College Park, Maryland 20742 (United States); Aprahamian, A. [Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Wiescher, M. [Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Batchelder, J. C. [UNIRIB, Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831 (United States); Bingham, C. R. [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States); Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Brenner, D. S. [Department of Chemistry, Clark University, Worcester, Massachusetts 01610 (United States); Ginter, T. N. [Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States); Gross, C. J. [UNIRIB, Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831 (United States); Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] (and others)

2000-03-06

170

Influence of neutron capture rates in the rare earth region on the r-process abundance pattern  

NASA Astrophysics Data System (ADS)

We study the sensitivity of the r-process abundance pattern to neutron capture rates along the rare earth region (A˜150 to A˜180). We introduce the concepts of large nuclear flow and flow saturation, which determine the neutron capture rates that are influential in setting the rare earth abundances. We illustrate the value of the two concepts by considering high entropy conditions favorable for rare earth peak production and identifying important neutron capture rates among the rare earth isotopes. We also show how these rates influence nuclear flow and specific sections of the abundance pattern.

Mumpower, Matthew R.; McLaughlin, Gail C.; Surman, Rebecca

2012-09-01

171

GENERAL THEOREMS FOR NUMERICAL APPROXIMATION OF STOCHASTIC PROCESSES ON THE HILBERT SPACE R  

Microsoft Academic Search

Abstract. General theorems for the numerical approximation on the separable Hilbert space,IR of cadlag, -adapted stochastic processes with -integrable second moments is presented for nonrandom intervals and positive measure,. The use of the theorems is illustrated by the special case of systems of ordinary stochastic differential equations (SDEs) and their numerical approximation given by the drift-implicit Euler method under one-sided

Henri Schurz

172

Functional cooperation of the mitochondrial processing peptidase subunits 1 1 Edited by R. Huber  

Microsoft Academic Search

Domains important for the activity of the heterodimeric mitochondrial processing peptidase (MPP) were investigated, by inserting one alanine residue at ten positions along the polypeptide chain of the ?-subunit (?-MPP). An alanine residue inserted after Glu70, Ser114, Lys215 and Ser314 respectively, abolished the cleavage activity of MPP. When the ?-subunit (?-MPP) was co-expressed with N-terminal hexa-histidine tagged ?-MPP, ?-MPP was

Pierre Luciano; Séverine Geoffroy; Anders Brandt; Jean-François Hernandez; Vincent Géli

1997-01-01

173

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

SciTech Connect

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.

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

2010-07-01

174

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

NASA Astrophysics Data System (ADS)

The ? 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.

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.; Ku?niak, A.; Mazzocchi, C.; Mendez, A. J., II; Miernik, K.; Padgett, S. W.; Paulauskas, S. V.; Ramayya, A. V.; Winger, J. A.; Woli?ska-Cichocka, M.; Zganjar, E. F.

2012-09-01

175

New half-lives of r-process Zn and Ga isotopes measured with electromagnetic separation.  

PubMed

The ? decays of neutron-rich nuclei near the doubly magic (78)Ni were studied at the Holifield Radioactive Ion Beam Facility using an electromagnetic isobar separator. The half-lives of (82)Zn (228±10??ms), (83)Zn (117±20??ms), and (85)Ga (93±7??ms) 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 (78)Ni 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. PMID:23005622

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; Ku?niak, A; Mazzocchi, C; Mendez, A J; Miernik, K; Padgett, S W; Paulauskas, S V; Ramayya, A V; Winger, J A; Woli?ska-Cichocka, M; Zganjar, E F

2012-09-13

176

Strong dependence between functional domains in a dual-function snoRNA infers coupling of rRNA processing and modification events  

PubMed Central

Most small nucleolar RNAs (snoRNAs) guide rRNA nucleotide modifications, some participate in pre-rRNA cleavages, and a few have both functions. These activities involve direct base-pairing of the snoRNA with pre-rRNA using different domains. It is not known if the modification and processing functions occur independently or in a coordinated manner. We address this question by mutational analysis of a yeast box H/ACA snoRNA that mediates both processing and modification. This snoRNA (snR10) contains canonical 5?- and 3?-hairpin structures with a guide domain for pseudouridylation in the 3? hairpin. Our functional mapping results show that: (i) processing requires the 5? hairpin exclusively, in particular a 7-nt element; (ii) loss of the 3? hairpin or pseudouridine does not affect rRNA processing; (iii) a single nucleotide insertion in the guide domain shifts modification to an adjacent uridine in rRNA, and severely impairs both processing and cell growth; and (iv) the deleterious effects of the insertion mutation depend on the presence of the processing element in the 5? hairpin, but not modification of the novel site. Together, the results suggest that the snoRNA hairpins function in a coordinated manner and that their interactions with pre-rRNA could be coupled.

Liang, Xue-hai; Liu, Qing; Liu, Quansheng; King, Thomas H.; Fournier, Maurille J.

2010-01-01

177

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

SciTech Connect

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.

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

1980-01-01

178

Cotranscription and processing of 23S, 4.5S and 5S rRNA in chloroplasts from Zea mays.  

PubMed Central

The termini of rRNA processing intermediates and of mature rRNA species encoded by the 3' terminal region of 23S rDNA, by 4.5S rDNA, by the 5' terminal region of 5S rDNA and by the 23S/4.5S/5S intergenic regions from Zea mays chloroplast DNA were determined by using total RNA isolated from maize chloroplasts and 32P-labelled rDNA restriction fragments of these regions for nuclease S1 and primer extension mapping. Several processing sites detectable by both 3' and 5' terminally labelled probes could be identified and correlated to the secondary structure for the 23S/4.5S intergenic region. The complete 4.5S/5S intergenic region can be reverse transcribed and a common processing site for maturation of 4.5S and 5S rRNA close to the 3' end of 4.5S rRNA was detected. It is therefore concluded that 23S, 4.5S and 5S rRNA are cotranscribed. Images

Strittmatter, G; Kossel, H

1984-01-01

179

Molybdenum, Ruthenium, and the Heavy r-process Elements in Moderately Metal-poor Main-sequence Turnoff Stars  

NASA Astrophysics Data System (ADS)

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.

Peterson, Ruth C.

2013-05-01

180

Resonant active-sterile neutrino conversion and r-process nucleosynthesis in neutrino-heated supernova ejecta  

NASA Astrophysics Data System (ADS)

The neutrino-driven wind of a Type II supernova, is a likely site for the rapid neutron capture process (r-process) of heavy-element nucleosynthesis. Detailed models of the wind, however, have difficulty reproducing the solar system abundance pattern. In particular, models tend to find a ratio of neutrons to seed nuclei which is too low to account for the abundances of the heaviest elements, around A = 195. One way to increase the neutron-to-seed ratio is to increase the abundance of neutrons, or equivalently, to decrease the electron fraction in the wind. We study matter-enhanced neutrino transformation in the wind, using the channels ne- ns and ne- ns , where ns is a sterile neutrino species. This mechanism can convert most of the ne 's to sterile species, while leaving most of the ne 's active. The disappearance of the ne population has two effects. It dramatically lowers the electron fraction, since charged-current ne captures on protons are not balanced by ne captures on neutrons. It also enervates the ``alpha effect,'' where ne captures on protons during the formation of a particles reduce the neutron richness of material in the wind. We therefore find that active-sterile neutrino transformation will increase the neutron-to-seed ratio, helping the supernova r-process produce the heaviest observed nuclei. However, neutrino-neutrino interactions may prevent active-sterile transformation of the kind we discuss. We present preliminary calculations of this effect, and suggest directions for future research.

Fetter, Jonathan Morton

2000-11-01

181

First stars. I. The extreme r-element rich, iron-poor halo giant CS 31082-001. Implications for the r-process site(s) and radioactive cosmochronology  

Microsoft Academic Search

We present a high-resolution (R= 75 000, S\\/N ~ 500) spectroscopic analysis of the bright (V= 11.7), extreme halo giant CS 31082-001 ([Fe\\/H] = -2.9), obtained in an ESO-VLT Large Programme dedicated to very metal-poor stars. We find CS 31082-001 to be extremely rich in r-process elements, comparable in this respect only to the similarly metal-poor, but carbon-enriched, giant CS

V. Hill; B. Plez; R. Cayrel; T. C. Beers; B. Nordström; J. Andersen; M. Spite; F. Spite; B. Barbuy; P. Bonifacio; E. Depagne; P. François; F. Primas

2002-01-01

182

The B-spline R-matrix method for atomic processes: application to atomic structure, electron collisions and photoionization  

NASA Astrophysics Data System (ADS)

The basic ideas of the B-spline R-matrix (BSR) approach are reviewed, and the use of the method is illustrated with a variety of applications to atomic structure, electron-atom collisions and photo-induced processes. Special emphasis is placed on complex, open-shell targets, for which the method has proven very successful in reproducing, for example, a wealth of near-threshold resonance structures. Recent extensions to a fully relativistic framework and intermediate energies have allowed for an accurate treatment of heavy targets as well as a fully nonperturbative scheme for electron-impact ionization. Finally, field-free BSR Hamiltonian and electric dipole matrices can be employed in the time-dependent treatment of intense short-pulse laser-atom interactions.

Zatsarinny, Oleg; Bartschat, Klaus

2013-06-01

183

The essential WD-repeat protein Rsa4p is required for rRNA processing and intra-nuclear transport of 60S ribosomal subunits  

PubMed Central

We report the characterization of a novel factor, Rsa4p (Ycr072cp), which is essential for the synthesis of 60S ribosomal subunits. Rsa4p is a conserved WD-repeat protein that seems to localize in the nucleolus. In vivo depletion of Rsa4p results in a deficit of 60S ribosomal subunits and the appearance of half-mer polysomes. Northern hybridization and primer extension analyses of pre-rRNA and mature rRNAs show that depletion of Rsa4p leads to the accumulation of the 27S, 25.5S and 7S pre-rRNAs, resulting in a reduction of the mature 25S and 5.8S rRNAs. Pulse–chase analyses of pre-rRNA processing reveal that, at least, this is due to a strong delay in the maturation of 27S pre-rRNA intermediates to mature 25S rRNA. Furthermore, depletion of Rsa4p inhibited the release of the pre-60S ribosomal particles from the nucleolus to the nucleoplasm, as judged by the predominantly nucleolar accumulation of the large subunit Rpl25-eGFP reporter construct. We propose that Rsa4p associates early with pre-60S ribosomal particles and provides a platform of interaction for correct processing of rRNA precursors and nucleolar release of 60S ribosomal subunits.

de la Cruz, Jesus; Sanz-Martinez, Eloisa; Remacha, Miguel

2005-01-01

184

Dok-R Mediates Attenuation of Epidermal Growth Factor-Dependent Mitogen-Activated Protein Kinase and Akt Activation through Processive Recruitment of c-Src and Csk  

PubMed Central

Dok-R has previously been shown to associate with the epidermal growth factor receptor (EGFR) and become tyrosine phosphorylated in response to EGF stimulation. The recruitment of Dok-R to the EGFR, which is mediated through its phosphotyrosine binding (PTB) domain, results in attenuation of mitogen-activated protein kinase (MAPK) activation. Dok-R's ability to attenuate EGF-driven MAPK activation is independent of its ability to recruit rasGAP, a known attenuator of MAPK activity, suggesting an alternate Dok-R-mediated pathway. Herein, we have determined the structural determinants within Dok-R that are required for its ability to attenuate EGF signaling and to associate with c-Src and with the Src family kinase (SFK)-inhibitory kinase, Csk. We demonstrate that Dok-R associates constitutively with c-Src through an SH3-dependent interaction and that this association is essential to Dok-R's ability to attenuate c-Src activity and diminish MAPK and Akt/PKB activity. We further illustrate that EGF-dependent phosphorylation of Dok-R requires SFK activity and, more specifically, that SFK-dependent phosphorylation of tyrosine 402 on Dok-R facilitates the inducible recruitment of Csk. We propose that recruitment of Csk to Dok-R serves to bring Csk to c-Src and down-regulate its activity, resulting in a concomitant attenuation of MAPK and Akt/PKB activity. Furthermore, we demonstrate that Dok-R can abrogate c-Src's ability to protect the breast cancer cell line SKBR3 from anoikis and that an association with c-Src and Csk is required for this activity. Collectively these results demonstrate that Dok-R acts as an EGFR-recruited scaffolding molecule that processively assembles c-Src and Csk to attenuate signaling from the EGFR.

Van Slyke, Paul; Coll, Mariano Loza; Master, Zubin; Kim, Harold; Filmus, Jorge; Dumont, Daniel J.

2005-01-01

185

Dok-R mediates attenuation of epidermal growth factor-dependent mitogen-activated protein kinase and Akt activation through processive recruitment of c-Src and Csk.  

PubMed

Dok-R has previously been shown to associate with the epidermal growth factor receptor (EGFR) and become tyrosine phosphorylated in response to EGF stimulation. The recruitment of Dok-R to the EGFR, which is mediated through its phosphotyrosine binding (PTB) domain, results in attenuation of mitogen-activated protein kinase (MAPK) activation. Dok-R's ability to attenuate EGF-driven MAPK activation is independent of its ability to recruit rasGAP, a known attenuator of MAPK activity, suggesting an alternate Dok-R-mediated pathway. Herein, we have determined the structural determinants within Dok-R that are required for its ability to attenuate EGF signaling and to associate with c-Src and with the Src family kinase (SFK)-inhibitory kinase, Csk. We demonstrate that Dok-R associates constitutively with c-Src through an SH3-dependent interaction and that this association is essential to Dok-R's ability to attenuate c-Src activity and diminish MAPK and Akt/PKB activity. We further illustrate that EGF-dependent phosphorylation of Dok-R requires SFK activity and, more specifically, that SFK-dependent phosphorylation of tyrosine 402 on Dok-R facilitates the inducible recruitment of Csk. We propose that recruitment of Csk to Dok-R serves to bring Csk to c-Src and down-regulate its activity, resulting in a concomitant attenuation of MAPK and Akt/PKB activity. Furthermore, we demonstrate that Dok-R can abrogate c-Src's ability to protect the breast cancer cell line SKBR3 from anoikis and that an association with c-Src and Csk is required for this activity. Collectively these results demonstrate that Dok-R acts as an EGFR-recruited scaffolding molecule that processively assembles c-Src and Csk to attenuate signaling from the EGFR. PMID:15831486

Van Slyke, Paul; Coll, Mariano Loza; Master, Zubin; Kim, Harold; Filmus, Jorge; Dumont, Daniel J

2005-05-01

186

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

SciTech Connect

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.

Aoki, Wako [National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Beers, Timothy C. [Department of Physics and Astronomy and JINA: Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824-1116 (United States); Honda, Satoshi [Kwasan Observatory, Kyoto University, Ohmine-cho Kita Kazan, Yamashina-ku, Kyoto 607-847 (Japan); Carollo, Daniela, E-mail: aoki.wako@nao.ac.j, E-mail: beers@pa.msu.ed, E-mail: honda@kwasan.kyoto-u.ac.j, E-mail: carollo@mso.anu.edu.a [Research School of Astronomy and Astrophysics, Australian National University and Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611 (Australia)

2010-11-10

187

Scalable, efficient process for the synthesis of ( R)-3,5-bistrifluoromethylphenyl ethanol via catalytic asymmetric transfer hydrogenation and isolation as a DABCO inclusion complex  

Microsoft Academic Search

(R)-3,5-Bistrifluoromethylphenyl ethanol 2, a key building block in the synthesis of aprepitant, has been synthesized from ketone 5 via catalytic asymmetric transfer hydrogenation using a simplified catalyst generation procedure. The process uses (1S,2R)-cis-1-aminoindan-2-ol 10 and dichloro(p-cymene)Ru(II)dimer 9 as the chiral ligand and metal source for the reduction. While the reduction provides 2 in 90–92% ee, an isolation of 2 as

Karl B. Hansen; Jennifer R. Chilenski; Richard Desmond; Paul N. Devine; Edward J. J. Grabowski; Richard Heid; Michele Kubryk; David J. Mathre; Richard Varsolona

2003-01-01

188

Shelf Edge Exchange Processes-2: Seep2-02, R/V CAPE HATTERAS cruise CH01-88  

SciTech Connect

The R/V CAPE HATTERAS cruise CH01-88, SEEP2-02, took place from 3--20 March, 1988 and focused primarily on biological processes in the SEEP2 area. A short term sediment trap mooring was deployed near mooring 1 and recovered during the cruise. The mooring consisted of two 0.07 sq. meter and one 0.7 sq. meter sediment traps. Two time series, approximately 48 hours each, were conducted in the area of the sediment trap mooring. The time series were designed to study primary and secondary productivity and involved sampling nutrients, dissolved oxygen, chlorophyll, zooplankton abundance and distribution, and zooplankton fecal pellet distribution. Experiments to estimate grazing rates and fecal pellet production of the dominant copepods were also done. Sediment trap and zooplankton data are not reported here. During this cruise 99 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 a, dissolved oxygen, and particulate organic carbon and nitrogen.

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

1989-11-01

189

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

PubMed

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

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

2012-09-15

190

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

PubMed Central

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

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

2000-01-01

191

Novel processing in a mammalian nuclear 28S pre-rRNA: tissue-specific elimination of an 'intron' bearing a hidden break site.  

PubMed Central

Splitting and apparent splicing of ribosomal RNA, both previously unknown in vertebrates, were found in rodents of the genus Ctenomys. Instead of being formed by a single molecule of 4.4 kb, 28S rRNA is split in two molecules of 2.6 and 1.8 kb. A hidden break, mapping within a 106 bp 'intron' located in the D6 divergent region, is expressed in mature ribosomes of liver, lung, heart and spleen, as well as in primary fibroblast cultures. Testis-specific processing eliminates the intron and concomitantly the break site, producing non-split 28S rRNA molecules exclusively in this organ. The intron is flanked by two 9 bp direct repeats, revealing the acquisition by insertion of a novel rRNA processing strategy in the evolution of higher organisms.

Melen, G J; Pesce, C G; Rossi, M S; Kornblihtt, A R

1999-01-01

192

Two-electron photoionization processes in He@C60 using the R-matrix with pseudostates and time-dependent close-coupling methods  

NASA Astrophysics Data System (ADS)

The R-matrix with pseudostates method is applied to the case of two-electron excitation and ionization processes in He@C60. A finite spherical-well potential, which simulates the effect of the fullerene enclosing cage, is incorporated into the Hamiltonian using a modified R-matrix method, as recently applied to similar single photoionization studies of Xe@C60 and Ca@C60. Comparison is made with time-dependent close-coupling results for two-electron processes in He and He@C60, and excellent agreement is found in the respective descriptions of confinement resonances. Earlier findings are confirmed that the cage potential causes a redistribution between the n = 2 and n = 3 photoionization-excitation cross sections. The R-matrix with pseudostates method, in particular, is well-suited for treating atomic Feshbach resonances and studying multi-electron systems.

Gorczyca, T. W.; Lee, Teck-Ghee; Pindzola, M. S.

2013-10-01

193

beta-decay half-lives of neutron-rich isotopes of Fe, Co, Ni involved in the beginning of the r-process.  

National Technical Information Service (NTIS)

The very neutron-rich Fe- to Ni-isotopes are of interest since they are located at the very beginning of the astrophysical r-process path. The (beta)-decay half-lives of several isotopes, identified in thermal fission of (sup 235)U or (sup 239)Pu, have be...

S. Czajkowski M. Bernas P. Armbruster H. Faust J. P. Bocquet

1992-01-01

194

Transcript-Based Cloning of RRP46, a Regulator of rRNA Processing and R Gene-Independent Cell Death in Barley-Powdery Mildew Interactions[W][OA  

PubMed Central

Programmed cell death (PCD) plays a pivotal role in plant development and defense. To investigate the 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) challenged barley (Hordeum vulgare) cultivar C.I. 16151 (harboring the Mla6 powdery mildew resistance allele) and its fast neutron–derived Bgh-induced tip cell death1 mutant, bcd1. Mixed linear model analysis identified genes associated with the cell death phenotype as opposed to R gene–mediated resistance. One-hundred fifty genes were found at the threshold P value < 0.0001 and a false discovery rate <0.6%. Of these, 124 were constitutively overexpressed in the bcd1 mutant. Gene Ontology and rice (Oryza sativa) alignment-based annotation indicated that 68 of the 124 overexpressed genes encode ribosomal proteins. A deletion harboring six genes on chromosome 5H cosegregates with bcd1-specified cell death and is associated with misprocessing of rRNAs but segregates independent of R gene–mediated resistance. Barley stripe mosaic virus-induced gene silencing of one of the six deleted genes, RRP46 (rRNA-processing protein 46), phenocopied bcd1-mediated tip cell death. These findings suggest that RRP46, a critical component of the exosome core, mediates RNA processing and degradation involved in cell death initiation as a result of attempted penetration by Bgh during the barley–powdery mildew interaction but is independent of gene-for-gene resistance.

Xi, Liu; Moscou, Matthew J.; Meng, Yan; Xu, Weihui; Caldo, Rico A.; Shaver, Miranda; Nettleton, Dan; Wise, Roger P.

2009-01-01

195

The effects of diffusive exchange in heterogeneous systems on N.M.R. line shapes and relaxation processes  

Microsoft Academic Search

The effects of diffusive exchange on N.M.R. line shapes and relaxation times are of considerable importance in the interpretation of N.M.R. data from biological and heterogeneous systems, but have not been fully explored theoretically. In order to illustrate the effects, exact analytical solutions of the generalized Bloch equations are derived for various model situations describing heterogeneous systems. The first model

P. S. Belton; B. P. Hills

1987-01-01

196

Role of the ITS2-proximal stem and evidence for indirect recognition of processing sites in pre-rRNA processing in yeast  

Microsoft Academic Search

Eucaryotic ribosome biogenesis involves many cis-acting sequences and trans-acting factors, including snoRNAs. We have used directed muta- genesis of rDNA plasmids in yeast to identify critical sequence and structural elements within and flanking the ITS2-proximal stem. This base paired structure, present in the mature ribosome, is formed between the 5'-end of 25 Sa nd the3'-end of 5.8S rRNAs. Previously we

Colette A. Côté; Brenda A. Peculis

197

Xenopus U3 snoRNA GAC-Box A? and Box A Sequences Play Distinct Functional Roles in rRNA Processing  

PubMed Central

Mutations in the 5? portion of Xenopus U3 snoRNA were tested for function in oocytes. The results revealed a new cleavage site (A0) in the 3? region of vertebrate external transcribed spacer sequences. In addition, U3 mutagenesis uncoupled cleavage at sites 1 and 2, flanking the 5? and 3? ends of 18S rRNA, and generated novel intermediates: 19S and 18.5S pre-rRNAs. Furthermore, specific nucleotides in Xenopus U3 snoRNA that are required for cleavages in pre-rRNA were identified: box A is essential for site A0 cleavage, the GAC-box A? region is necessary for site 1 cleavage, and the 3? end of box A? and flanking nucleotides are required for site 2 cleavage. Differences between metazoan and yeast U3 snoRNA-mediated rRNA processing are enumerated. The data support a model where metazoan U3 snoRNA acts as a bridge to draw together the 5? and 3? ends of the 18S rRNA coding region within pre-rRNA to coordinate their cleavage.

Borovjagin, Anton V.; Gerbi, Susan A.

2001-01-01

198

R&D collaboration networks in the European framework programmes: data processing, network construction and selected results  

Microsoft Academic Search

We describe the construction of a large and novel data set on R&D collaboration networks in the first five EU Framework Programmes (FPs), examine key features and provide economic interpretations for our findings. The data set is based on publicly available raw data that presents numerous challenges. We critically examine the different problems and detail how we have dealt with

Thomas Roediger-Schluga; Michael Barber

2007-01-01

199

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

NASA Astrophysics Data System (ADS)

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,?). 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, ?n/??. The reaction rates for B11,12(n,?) 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.

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

200

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

PubMed

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

Anantha, Narayana D B

2013-01-01

201

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

PubMed Central

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.

Anantha, Narayana D. B.

2013-01-01

202

Two R Process Components in Ultra-Metal-Poor Stars: The Neutron-Capture Element Distribution of CS 22892-052  

Microsoft Academic Search

The abundance patterns of neutron-capture elements in very metal-poor halo stars play a crucial role in guiding and constraining\\u000a theoretical models of nucleosynthesis. Many studies have suggested that the abundance patterns of the heavier (Z? 56) stable neutron-capture elements in very metal-poor halo stars are consistent with the solar system r-process abundance distribution, but this concordance breaks down for the

Bo Zhang; Ji Li; Yue-Xiang Wang; Yan-Xia Zhang; Jun-Hong Liu; Qiu-He Peng

2002-01-01

203

The rRNA-Processing Function of the Yeast U14 Small Nucleolar RNA Can Be Rescued by a Conserved RNA Helicase-Like Protein  

Microsoft Academic Search

The phylogenetically conserved U14 small nucleolar RNA is required for processing of rRNA, and this function involves base pairing with conserved complementary sequences in 18S RNA. With a view to identifying other important U14 interactions, a stem-loop domain required for activity of Saccharomyces cerevisiae U14 RNAs (the Y domain) was first subjected to detailed mutational analysis. The mapping results showed

WEN-QING LIANG; JEFFREY A. CLARK; MAURILLE J. FOURNIER

1997-01-01

204

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

NASA Astrophysics Data System (ADS)

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 industry for the GOES-R system and their related broad scope of acquisition activities.

Huang, Hung-Lung

2005-08-01

205

Experiments with a methodology to model the role of R&D expenditures in energy technology learning processes; first results  

Microsoft Academic Search

This paper presents the results of using a stylized optimization model of the global electricity supply system to analyze the optimal research and development (R&D) support for an energy technology. The model takes into account the dynamics of technological progress as described by a so-called two-factor learning curve (2FLC). The two factors are cumulative experience (“learning by doing”) and accumulated

Asami Miketa; Leo Schrattenholzer

2004-01-01

206

First stars. I. The extreme r-element rich, iron-poor halo giant CS 31082-001. Implications for the r-process site(s) and radioactive cosmochronology  

NASA Astrophysics Data System (ADS)

We present a high-resolution (R= 75 000, S/N ~ 500) spectroscopic analysis of the bright (V= 11.7), extreme halo giant CS 31082-001 ([Fe/H] = -2.9), obtained in an ESO-VLT Large Programme dedicated to very metal-poor stars. We find CS 31082-001 to be extremely rich in r-process elements, comparable in this respect only to the similarly metal-poor, but carbon-enriched, giant CS 22892-052. As a result of the extreme overabundance of the heaviest r-process elements, and negligible blending from CH and CN molecular lines, a reliable measurement is obtained of the U II line at 386 nm, for the first time in a halo star, along with numerous lines of Th II, as well as lines of 25 other r-process elements. Abundance estimates for a total of 43 elements (44 counting Hydrogen) are reported in CS 31082-001, almost half of the entire periodic table. The main atmospheric parameters of CS 31082-001 are as follows: Teff = 4825 +/- 50 K, log g= 1.5 +/- 0.3 (cgs), [Fe/H] = -2.9 +/- 0.1 (in LTE), and microturbulence 1.8 +/- 0.2 km s-1. Carbon and nitrogen are not significantly enhanced relative to iron. As usual in giant stars, Li is depleted by dilution (log (Li/H) = 0.85). The alpha -elements show the usual enhancements with respect to iron, with [O/Fe] = 0.6+/- 0.2 (from [O I] 6300 Å), [Mg/Fe] = 0.45 +/- 0.16, [Si/Fe] = 0.24 +/- 0.1, and [Ca/Fe] = 0.41 +/- 0.08, while [Al/Fe] is near -0.5. The r-process elements show unusual patterns: among the lightest elements (Z ~ 40), Sr and Zr follow the Solar r-element distribution, but Ag is down by 0.8 dex. All elements with 56 <= Z <= 72 follow the Solar r-element pattern, reduced by about 1.25 dex. Accordingly, the [r/Fe] enhancement is about +1.7 dex (a factor of 50), very similar to that of CS 22892-052. Pb, in contrast, seems to be below the shifted Solar r-process distribution, possibly indicating an error in the latter, while thorium is more enhanced than the lighter nuclides. In CS 31082-001, log(Th/Eu) is -0.22 +/- 0.07, higher than in the Solar System (-0.46) or in CS 22892-052 (-0.66). If CS 31082-001 and CS 22892-052 have similar ages, as expected for two extreme halo stars, this implies that the production ratios were different by about 0.4 dex for the two objects. Conversely, if the Th/Eu production ratio were universal, an age of 15 Gyr for CS 22892-052 would imply a negative age for CS 31082-001. Thus, while a universal production ratio for the r-process elements seems to hold in the interval 56 <= Z <= 72, it breaks down in the actinide region. When available, the U/Th is thus preferable to Th/Eu for radioactive dating, for two reasons: (i) because of its faster decay rate and smaller sensitivity to observational errors, and (ii) because the inital production ratio of the neighboring nuclides 238U and 232Th is more robustly predicted than the 151Eu/232Th ratio. Our current best estimate for the age of CS 31082-001 is 14.0+/- 2.4 Gyr. However, the computed actinide production ratios should be verified by observations of daughter elements such as Pb and Bi in the same star, which are independent of the subsequent history of star formation and nucelosynthesis in the Galaxy. Based on observations of program 165.N-0276(A) obtained with the Very Large Telescope of the European Southern Observatory at Paranal, Chile.

Hill, V.; Plez, B.; Cayrel, R.; Beers, T. C.; Nordström, B.; Andersen, J.; Spite, M.; Spite, F.; Barbuy, B.; Bonifacio, P.; Depagne, E.; François, P.; Primas, F.

2002-05-01

207

First stars. XV. Third-peak r-process element and actinide abundances in the uranium-rich star CS31082-001  

NASA Astrophysics Data System (ADS)

Context. A small fraction of extremely metal-poor (EMP) stars exhibit moderate to extreme excesses of heavy neutron-capture elements produced in the r-process. The production site(s) of these elements in the early Galaxy remain(s) unclear, as is the reason for their occasional enhancement in the otherwise regular pattern of abundances of elements up to the iron peak. The detailed abundance pattern of the heaviest elements in EMP stars provides insight into their origin and role in the chemical enrichment of the early Galaxy and in radioactive nucleochronology. Aims: The EMP giant star CS 31082-001 ([Fe/H] ~ -2.9) exhibits an extreme enhancement of neutron-capture elements ([r/Fe] ~ +1.7) with U and Th enhanced by a further ~+0.7 dex, and a minimum of blending by molecular lines such as CH or CN. A rich inventory of r-process element abundances was established previously from optical spectra. Here we aim to supplement these data with abundances from near-UV spectroscopy of the third-peak neutron-capture elements, which are crucial for understanding the synthesis of the heaviest elements. Methods: Near-UV spectra from HST/STIS were analysed with LTE model atmospheres and spectrum synthesis calculations to derive new abundances of Os, Ir, Pt, Au, Bi and Pb in CS 31082-001. Results: Together with earlier data, the resulting abundance pattern for the r-process elements provides improved constraints on the nature of the r-process. The observed U and Th abundances and the initial production ratio place CS 31082-001 as one of the oldest stars in the Galaxy, consistent with its extreme metal deficiency. Comparison with the heaviest stable reference elements and with the daughter nuclides Pb and Bi provides a consistency check on this age determination. Finally, the existence of such r-element rich stars indicate that the early chemical evolution of the Galaxy was localised and inhomogeneous. Based on observations made with the NASA/ESA Hubble Space Telescope (HST) through the Space Telescope Science Institute, operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555; and with the ESO Very Large Telescope at Paranal Observatory, Chile; Progr. ID 165.N-0276.

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

2011-10-01

208

Activation of BlaR1 Protein of Methicillin-resistant Staphylococcus aureus, Its Proteolytic Processing, and Recovery from Induction of Resistance*  

PubMed Central

The fates of BlaI, the gene repressor protein for the bla operon, BlaR1, the ?-lactam sensor/signal transducer, and PC1 ?-lactamase in four strains of Staphylococcus aureus upon exposure to four different ?-lactam antibiotics were investigated as a function of time. The genes for the three proteins are encoded by the bla operon, the functions of which afford inducible resistance to ?-lactam antibiotics in S. aureus. BlaR1 protein is expressed at low copy number. Acylation of the sensor domain of BlaR1 by ?-lactam antibiotics initiates signal transduction to the cytoplasmic domain, a zinc protease, which is activated and degrades BlaI. This proteolytic degradation derepresses transcription of all three genes, resulting in inducible resistance. These processes take place within minutes of exposure to the antibiotics. The BlaR1 protein was shown to undergo fragmentation in three S. aureus strains within the time frame relevant for manifestation of resistance and was below the detection threshold in the fourth. Two specific sites of fragmentation were identified, one cytoplasmic and the other in the sensor domain. This is proposed as a means for turnover, a process required for recovery from induction of resistance in S. aureus in the absence of the antibiotic challenge. In S. aureus not exposed to ?-lactam antibiotics (i.e. not acylated by antibiotic) the same fragmentation of BlaR1 is still observed, including the shedding of the sensor domain, an observation that leads to the conclusion that the sites of proteolysis might have evolved to predispose the protein to degradation within a set period of time.

Llarrull, Leticia I.; Toth, Marta; Champion, Matthew M.; Mobashery, Shahriar

2011-01-01

209

Waste minimization/pollution prevention at R&D facilities: Implementing the SNL/NM Process Waste Assessment Program  

SciTech Connect

The Sandia National Laboratories, New Mexico (SNL/NM) Process Waste Assessment (PWA) program began formally on November 2, 1992. This program represents the first laboratory-wide attempt to explicitly identify and characterize SNL/NM`s waste generating processes for waste minimization purposes. This paper describes the major elements of the SNL/NM PWA program, the underlying philosophy for designing a PWA program at a highly diverse laboratory setting such as SNL/NM, and the experiences and insights gained from five months of implementing this living program. Specifically, the SNL/NM PWA program consists of four major, interrelated phases: (1) Process Definition, (2) Process Characterization, (3) Waste Minimization Opportunity Assessment, and (4) Project Evaluation, Selection, Implementation, and Tracking. This phased approach was developed to Provide a flexible, yet appropriate, level of detail to the multitude of different ``processes`` at SNL/NM. Using a staff infrastructure of approximately 60 Waste Minimization Network Representatives (MinNet Reps) and consulting support, the SNL/NM PWA program has become the linchpin of even more progressive and proactive environmental, safety, and health (ES&H) initiatives such as: (1) cradle-to-grove material/waste tracking, (2) centralized ES&H reporting, and (3) detailed baselining and tracking for measuring multi-media waste reduction goals. Specific examples from the SNL/NM PWA program are provided, including the results from Process Definition, Process Characterization, and Waste Minimization Opportunity Assessments performed for a typical SNL/NM process.

Kjeldgaard, E.A.; Stermer, D.L. [Sandia National Labs., Albuquerque, NM (United States); Saloio, J.H. Jr.; Lorton, G.A. [Ogden Environmental and Energy Services Co., Fairfax, VA (United States)

1993-05-01

210

Waste minimization/pollution prevention at R D facilities: Implementing the SNL/NM Process Waste Assessment Program  

SciTech Connect

The Sandia National Laboratories, New Mexico (SNL/NM) Process Waste Assessment (PWA) program began formally on November 2, 1992. This program represents the first laboratory-wide attempt to explicitly identify and characterize SNL/NM's waste generating processes for waste minimization purposes. This paper describes the major elements of the SNL/NM PWA program, the underlying philosophy for designing a PWA program at a highly diverse laboratory setting such as SNL/NM, and the experiences and insights gained from five months of implementing this living program. Specifically, the SNL/NM PWA program consists of four major, interrelated phases: (1) Process Definition, (2) Process Characterization, (3) Waste Minimization Opportunity Assessment, and (4) Project Evaluation, Selection, Implementation, and Tracking. This phased approach was developed to Provide a flexible, yet appropriate, level of detail to the multitude of different processes'' at SNL/NM. Using a staff infrastructure of approximately 60 Waste Minimization Network Representatives (MinNet Reps) and consulting support, the SNL/NM PWA program has become the linchpin of even more progressive and proactive environmental, safety, and health (ES H) initiatives such as: (1) cradle-to-grove material/waste tracking, (2) centralized ES H reporting, and (3) detailed baselining and tracking for measuring multi-media waste reduction goals. Specific examples from the SNL/NM PWA program are provided, including the results from Process Definition, Process Characterization, and Waste Minimization Opportunity Assessments performed for a typical SNL/NM process.

Kjeldgaard, E.A.; Stermer, D.L. (Sandia National Labs., Albuquerque, NM (United States)); Saloio, J.H. Jr.; Lorton, G.A. (Ogden Environmental and Energy Services Co., Fairfax, VA (United States))

1993-01-01

211

C1D and hMtr4p associate with the human exosome subunit PM/Scl-100 and are involved in pre-rRNA processing  

PubMed Central

The exosome is a complex of 3?–5? exoribonucleases and RNA-binding proteins, which is involved in processing or degradation of different classes of RNA. Previously, the characterization of purified exosome complexes from yeast and human cells suggested that C1D and KIAA0052/hMtr4p are associated with the exosome and thus might regulate its functional activities. Subcellular localization experiments demonstrated that C1D and KIAA0052/hMtr4p co-localize with exosome subunit PM/Scl-100 in the nucleoli of HEp-2 cells. Additionally, the nucleolar accumulation of C1D appeared to be dependent on PM/Scl-100. Protein–protein interaction studies showed that C1D binds to PM/Scl-100, whereas KIAA0052/hMtr4p was found to interact with MPP6, a previously identified exosome-associated protein. Moreover, we demonstrate that C1D, MPP6 and PM/Scl-100 form a stable trimeric complex in vitro. Knock-down of C1D, MPP6 and KIAA0052/hMtr4p by RNAi resulted in the accumulation of 3?-extended 5.8S rRNA precursors, showing that these proteins are required for rRNA processing. Interestingly, C1D appeared to contain RNA-binding activity with a potential preference for structured RNAs. Taken together, our results are consistent with a role for the exosome-associated proteins C1D, MPP6 and KIAA052/hMtr4p in the recruitment of the exosome to pre-rRNA to mediate the 3? end processing of the 5.8S rRNA.

Schilders, Geurt; van Dijk, Erwin; Pruijn, Ger J.M.

2007-01-01

212

Static and Fatigue Testing of Full-Scale Fuselage Panels Fabricated Using a Therm-X(R) Process.  

National Technical Information Service (NTIS)

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 we...

A. J. Dinicola C. Kassapoglou J. C. Chou

1992-01-01

213

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 ...

214

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

SciTech Connect

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

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

1987-01-01

215

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

PubMed Central

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. Images

Echeverria, M; Lahmy, S

1995-01-01

216

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

PubMed Central

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 that STD and BEAM processing resulted in significantly poorer RTSs in 70 dB SPL noise compared to the performance with these processing conditions in 60 dB SPL noise. Bilateral participants demonstrated a bilateral improvement compared to the better monaural condition for both noise levels and all processing conditions, except ASC in 60 dB SPL noise. Conclusions The results of this study suggest that the use of processing options that utilize noise reduction, like that available in ASC and BEAM, improve a CI recipient’s ability to understand speech in noise in listening situations similar to those experienced in the real-world. The choice of the best processing option is dependent on the noise level, with BEAM best at moderate noise levels and ASC best at loud noise levels for unilateral CI recipients. Therefore, multiple noise programs or a combination of processing options may be necessary to provide CI users with the best performance in a variety of listening situations.

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

2013-01-01

217

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

USGS Publications Warehouse

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

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

1984-01-01

218

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)

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.

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

2012-12-01

219

NOL11, Implicated in the Pathogenesis of North American Indian Childhood Cirrhosis, Is Required for Pre-rRNA Transcription and Processing  

PubMed Central

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

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

2012-01-01

220

A MECHANISTIC MODEL FOR ESTIMATING VOC EMISSIONS FROM INDUSTRIAL PROCESS DRAINS PART I: THE UNDERLYING CHANNEL. (R823335)  

EPA Science Inventory

Recent research has indicated the potential for emissions of volatile organic compound (VOCs) from industrial process drains, and a need for better understanding of the mass transfer kinetics associated with such emissions. rn this study, a two-zone model was developed in a...

221

Automated synthesis of pipelined designs on FPGAs for signal and image processing applications described in MATLAB(R)  

Microsoft Academic Search

We present a compiler that takes high level algorithms described in MATLAB and generates an optimized hardware for an FPGA with external memory. A framework is described to detect and exploit opportunities to pipeline loops in an optimal way. Effectiveness of the framework is demonstrated by synthesizing some image and signal processing applications. Starting from the MATLAB description of the

Malay Haldar; Anshuman Nayak; A. Choudhary; Prith Banerjee

2001-01-01

222

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....

223

Classroom Interpreting and Visual Information Processing in Mainstream Education for Deaf Students: Live or Memorex[R]?  

ERIC Educational Resources Information Center

This study examined visual information processing and learning in classrooms including both deaf and hearing students. Of particular interest were the effects on deaf students' learning of live (three-dimensional) versus video-recorded (two-dimensional) sign language interpreting and the visual attention strategies of more and less experienced…

Marschark, Marc; Pelz, Jeff B.; Convertino, Carol; Sapere, Patricia; Arndt, Mary Ellen; Seewagen, Rosemarie

2005-01-01

224

Multi-process demonstration plant preliminary design\\/economic evaluation. R and D report No. 114, Interim report No. 7  

Microsoft Academic Search

The MPDP design consists of the following: three principal process plants; coal receiving storage and handling facilities; and the necessary ancillaries to service the plants and a plant population of approximately 530 people. The key elements of the three plants are: plant 1 is a low pressure coal gasifier, which can be operated either in the air-blown or oxygen-blown mode,

J. B. OHara; A. Bela; N. E. Jentz; H. W. Klumpe; B. I. Loran; P. F. McElherne; R. V. Teeple

1978-01-01

225

{beta}-Decay Half-Lives of Very Neutron-Rich Kr to Tc Isotopes on the Boundary of the r-Process Path: An Indication of Fast r-Matter Flow  

SciTech Connect

The {beta}-decay half-lives of 38 neutron-rich isotopes from {sub 36}Kr to {sub 43}Tc have been measured; the half-lives of {sup 100}Kr, {sup 103-105}Sr, {sup 106-108}Y, {sup 108-110}Zr, {sup 111,112}Nb, {sup 112-115}Mo, and {sup 116,117}Tc are reported here. The results when compared with previous standard models indicate an overestimation in the predicted half-lives by a factor of 2 or more in the A{approx_equal}110 region. A revised model based on the second generation gross theory of {beta} decay better predicts the measured half-lives and suggests a more rapid flow of the rapid neutron-capture process (r-matter flow) through this region than previously predicted.

Nishimura, S.; Li, Z.; Watanabe, H.; Kurata-Nishimura, M.; Baba, H.; Doornenbal, P.; Isobe, T.; Sakurai, H.; Scheit, H.; Steppenbeck, D. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Yoshinaga, K. [Department of Physics, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Sumikama, T.; Miyashita, Y.; Chiba, J.; Nakano, T.; Sugimoto, K.; Takano, S. [Department of Physics, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Tachibana, T. [4 Senior High School of Waseda University, Nerima Tokyo 177-0044 (Japan); Yamaguchi, K.; Odahara, A. [Department of Physics, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043 (Japan)

2011-02-04

226

Gradual processing of the ITS1 from the nucleolus to the cytoplasm during synthesis of the human 18S rRNA  

PubMed Central

Defects in ribosome biogenesis trigger stress response pathways, which perturb cell proliferation and differentiation in several genetic diseases. In Diamond–Blackfan anemia (DBA), a congenital erythroblastopenia, mutations in ribosomal protein genes often interfere with the processing of the internal transcribed spacer 1 (ITS1), the mechanism of which remains elusive in human cells. Using loss-of-function experiments and extensive RNA analysis, we have defined the precise position of the endonucleolytic cleavage E in the ITS1, which generates the 18S-E intermediate, the last precursor to the 18S rRNA. Unexpectedly, this cleavage is followed by 3?–5? exonucleolytic trimming of the 18S-E precursor during nuclear export of the pre-40S particle, which sets a new mechanism for 18S rRNA formation clearly different from that established in yeast. In addition, cleavage at site E is also followed by 5?–3? exonucleolytic trimming of the ITS1 by exonuclease XRN2. Perturbation of this step on knockdown of the large subunit ribosomal protein RPL26, which was recently associated to DBA, reveals the putative role of a highly conserved cis-acting sequence in ITS1 processing. These data cast new light on the original mechanism of ITS1 elimination in human cells and provide a mechanistic framework to further study the interplay of DBA-linked ribosomal proteins in this process.

Preti, Milena; O'Donohue, Marie-Francoise; Montel-Lehry, Nathalie; Bortolin-Cavaille, Marie-Line; Choesmel, Valerie; Gleizes, Pierre-Emmanuel

2013-01-01

227

The Astrophysical {ital r}-Process: A Comparison of Calculations following Adiabatic Expansion with Classical Calculations Based on Neutron Densities and Temperatures  

SciTech Connect

The rapid neutron-capture process ({ital r}-process) encounters unstable nuclei far from {beta}-stability. Therefore its observable features, like the abundances, witness (still uncertain) nuclear structure as well as the conditions in the appropriate astrophysical environment. With the remaining lack of a full understanding of its astrophysical origin, parameterized calculations are still needed. We consider two approaches: (1) the classical approach is based on (constant) neutron number densities n{sub n} and temperatures {ital T} over duration timescales {tau}; (2) recent investigations, motivated by the neutrino wind scenario from hot neutron stars after a supernova explosion, followed the expansion of matter with initial entropies {ital S} and electron fractions Y{sub e} over expansion timescales {tau}. In the latter case the freezeout of reactions with declining temperatures and densities can be taken into account explicitly. We compare the similarities and differences between the two approaches with respect to resulting abundance features and their relation to solar {ital r}-process abundances, applying for the first time different nuclear mass models in entropy-based calculations. Special emphasis is given to the questions of ({ital a}) whether the same nuclear properties far from stability lead to similar abundance patterns and possible deficiencies in (1) and (2), and ({ital b}) whether some features can also provide clear constraints on the astrophysical conditions in terms of permitted entropies, Y{sub e} values, and expansion timescales in (2). This relates mostly to the A{lt}110 mass range, where a fit to solar {ital r}-abundances in high-entropy supernova scenarios seems to be hard to attain. Possible low-entropy alternatives are presented. {copyright} {ital {copyright} 1999.} {ital The American Astronomical Society}

Freiburghaus, C. [Institute for Theoretical Physics, University of California at Santa Barbara, Santa Barbara, CA 93106-4030 (United States); Rembges, J.; Rauscher, T. [Departement fuer Physik und Astronomie, Universitaet Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Kolbe, E. [Institute for Theoretical Physics, University of California at Santa Barbara, Santa Barbara, CA 93106-4030 (United States); Thielemann, F. [Institute for Theoretical Physics, University of California at Santa Barbara, Santa Barbara, CA 93106-4030 (United States)]|[Departement fuer Physik und Astronomie, Universitaet Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Kratz, K.; Pfeiffer, B. [Institut fuer Kernchemie, Universitaet Mainz, Fritz-Strassmann-Weg 2, D-55099 Mainz (Germany); Cowan, J.J. [Institute for Theoretical Physics, University of California at Santa Barbara, Santa Barbara, CA 93106-4030 (United States)]|[Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)

1999-05-01

228

Effect of process variables on supercritical fluid disruption of Ralstonia eutropha cells for poly(R-hydroxybutyrate) recovery.  

PubMed

This research focuses on the disruption of the gram-negative bacterium Ralstonia eutropha cells by supercritical CO2 for poly(R-hydroxybutyrate) (PHB) recovery. The variables affecting cell disruption such as drying strategy, type of modifier, and cultivation time, as well as operating pressure, temperature, and repeated release of supercritical CO2 pressure, have been studied. Effect of this disruption technique on PHB molecular mass was also investigated. PHB recovery was examined using a combination of this method and chemical pretreatments. For salt pretreatment, the cells were exposed to 140 mM NaCl and heat (60 degrees C, 1 h). The cells were also exposed to 0.2-0.8% (w/w) NaOH to examine the effect of alkaline pretreatment. Bacterial cells treated in growth phase exhibited less resistance to disruption than nutrient-limited cells in the stationary phase. It was also found that the wet cells could be utilized to recover PHB, but purity of the product was lower than that obtained from freeze-dried cells. Pretreatment with a minimum of 0.4% (w/w) NaOH was necessary to enable complete disruption with two times pressure release. Salt pretreatment was less effective; however, disruption was improved by the application of alkaline shock. The proposed method is economic and comparable with other recovery methods in terms of the percentage of PHB recovery and energy consumption, while it is environmentally more benign. PMID:15575709

Khosravi-Darani, Kianoosh; Vasheghani-Farahani, Ebrahim; Shojaosadati, Seyed Abbas; Yamini, Yadollah

229

Measuring Hospital Care from the Patients' Perspective: An Overview of the CAHPS(R) Hospital Survey Development Process  

PubMed Central

Objective To describe the developmental process for the CAHPS® Hospital Survey. Study Design A pilot was conducted in three states with 19,720 hospital discharges. Methods of Analysis A rigorous, multi-step process was used to develop the CAHPS Hospital Survey. It included a public call for measures, multiple Federal Register notices soliciting public input, a review of the relevant literature, meetings with hospitals, consumers and survey vendors, cognitive interviews with consumer, a large-scale pilot test in three states and consumer testing and numerous small-scale field tests. Findings The current version of the CAHPS Hospital Survey has survey items in seven domains, two overall ratings of the hospital and five items used for adjusting for the mix of patients across hospitals and for analytical purposes. Conclusions The CAHPS Hospital Survey is a core set of questions that can be administered as a stand-alone questionnaire or combined with a broader set of hospital specific items.

Goldstein, Elizabeth; Farquhar, Marybeth; Crofton, Christine; Darby, Charles; Garfinkel, Steven

2005-01-01

230

{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

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.

Pereira, J.; Galaviz, D.; Matos, M.; Montes, F. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan (United States); Hennrich, S.; Kessler, R.; Schertz, F. [Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan (United States); Institut fuer Kernchemie, Universitaet Mainz, Mainz (Germany); Virtuelles Institut fuer Struktur der Kerne and Nuklearer Astrophysik, Mainz (Germany); Aprahamian, A.; Quinn, M.; Woehr, A. [Institute of Structure and Nuclear Astrophysics, University of Notre Dame, South Bend, Indiana (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, South Bend, Indiana (United States); Arndt, O.; Pfeiffer, B. [Institut fuer Kernchemie, Universitaet Mainz, Mainz (Germany); Virtuelles Institut fuer Struktur der Kerne and Nuklearer Astrophysik, Mainz (Germany); Becerril, A.; Elliot, T.; Estrade, A.; Lorusso, G.; Schatz, H. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan (United States); Kratz, K.-L. [Virtuelles Institut fuer Struktur der Kerne and Nuklearer Astrophysik, Mainz (Germany); Max Planck Institut fuer Chemie, Otto-Hahn-Institut, Mainz (Germany); Mantica, P. F. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan (United States); Department of Chemistry, Michigan State University, East Lansing, Michigan (United States); Moeller, P. [Theoretical Division, Los Alamos National Laboratory, New Mexico (United States)] (and others)

2009-03-15

231

Single nucleotide polymorphism associated with mature miR125a alters the processing of pri-miRNA  

Microsoft Academic Search

MicroRNAs (miRNAs) are small non-coding RNAs that inhibit expression of specific target genes at the post- transcriptional level. Sequence variations in miRNA genes, including pri-miRNAs, pre-miRNAs and mature miRNAs, could potentially influence the processing and\\/or target selection of miRNAs. In this study, we have systematically identified single nucleotide polymorphisms (SNPs) associated with 227 known human miRNAs. Among 323 total SNPs

Ranhui Duan; ChangHui Pak; Peng Jin

2007-01-01

232

{gamma}{gamma}{r_arrow}{ital Ze}{sup +}{ital e{minus}} and related processes using polarized photon beams  

SciTech Connect

The cross sections for processes with the production of {ital Z} and pairs of leptons or quarks in the {gamma}{gamma} collisions are calculated. They are large enough to give an important background for Higgs boson hunting at future photon colliders if the Higgs boson mass is about 100 GeV and they are small for the production of two {ital Z}`s. The equivalent electron approximation for the polarized photon beams is presented.

Ginzburg, I.F. [Institute of Mathematics, 630090, Novosibirsk (Russian Federation); Serbo, V.G. [Novosibirsk State University, 630090, Novosibirsk (Russian Federation)

1994-03-01

233

Process innovation in high-performance systems: From polymeric composites R&D to design and build of airplane showers  

NASA Astrophysics Data System (ADS)

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.

Wu, Yi-Jui

234

Psychometric evaluation of the Swedish adaptation of the Inventory for Assessing the Process of Cultural Competence Among Healthcare Professionals--Revised (IAPCC-R).  

PubMed

The purpose of this study was to describe the translation, adaption, and psychometric evaluation process in relation to validity and reliability of the Swedish version of the instrument, Inventory for Assessing The Process of Cultural Competence Among Healthcare Professionals-Revised (IAPCC-R) following the translation, adaptation, and psychometric evaluation process. Validity tests were conducted on the response processes (N = 15), the content (N = 7), and the internal structure of the instrument (N = 334). Reliability (alpha = .65 for the total scale varying between -.01 and .65 for the different subscales) was evaluated in terms of internal consistency. Results indicated weak validity and reliability though it is difficult to conclude whether this is related to adaptation issues or the original construction.The testing of the response process identified problems in relation to respondents' conceptualization of cultural competence. The test of the content identified a weak correspondence between the items and the underlying model. In addition, a confirmatory factor analysis did not confirm the proposed structure of the instrument. This study concludes that this instrument is not valid and reliable for use with a Swedish population of practicing nurses or nursing students. PMID:19822886

Olt, Helen; Jirwe, Maria; Gustavsson, Petter; Emami, Azita

2009-10-12

235

A Compendium of Causes and Effects of Processes at Transform Faults and Fracture Zones (Paper 7R0440)  

NASA Astrophysics Data System (ADS)

A flowchart has been constructed which consolidates into a single conceptual framework a large number of the phenomena and processes which have been observed or postulated at transform faults (TFs) and fracture zones (FZs). Oceanic ridge-ridge transform faults and their aseismic extensions are emphasized. The upstream end of the flowchart contains large-scale boundary conditions imposed by the position of a particular transform fault in space and time, for example, slip rate. The downstream end of the flowchart contains small-scale features characteristic of individual TFs or FZs, for example, the existence of a FZ-parallel ridge. Features of both the upstream and the downstream ends of the flowchart can be mapped, measured, or otherwise derived by direct observation. The middle of the flow chart includes processes and phenomena which are inferred to result from the upstream boundary conditions and to cause the downstream small-scale features, for example, thermal conduction across the plate boundary. Phenomena in this "black box" in the center of the flowchart cannot be directly observed with present technology but must be inferred. The advantages of ordering knowledge into such a flowchart are that inconsistancies, gaps in understanding, self-limiting phenomena (feedback loops), and previously unrecognized relationships stand out and that the boundary between inference and observation is clearly drawn.

Kastens, Kim A.

1987-08-01

236

{beta}-decay half-lives and {beta}-delayed neutron emission probabilities for neutron rich nuclei close to the N=82r-process path  

SciTech Connect

{beta}-delayed neutron emission branchings (or upper limits) for neutron rich {sup 116-120}Rh, {sup 120-122}Pd, and {sup 124}Ag have been measured. These branching ratios serve as direct inputs to astrophysical rapid neutron capture process models and affect the final abundances calculated in these models. In addition, half-lives for neutron rich {sup 114-115}Tc, {sup 114-118}Ru, {sup 116-121}Rh, and {sup 119-124}Pd near the proposed path of the r-process have also been measured. The results agree with theoretical quasiparticle random-phase approximation calculations within model uncertainties; the only exception is the delayed neutron branching in the decay of {sup 120}Rh, which is found to be much smaller than predicted.

Montes, F.; Estrade, A.; Hosmer, P.T.; Ouellette, M.; Schatz, H. [Joint Institute for Nuclear Astrophysics (United States); Dept. of Physics and Astronomy, Michigan State University, E. Lansing, Michigan 48824 (United States); National Superconducting Cyclotron Laboratory, Michigan State University, E. Lansing, Michigan 48824 (United States); Liddick, S.N.; Mantica, P.F.; Tomlin, B.E. [Dept. of Chemistry, Michigan State University, E. Lansing, Michigan 48824 (United States); National Superconducting Cyclotron Laboratory, Michigan State University, E. Lansing, Michigan 48824 (United States); Morton, A.C.; Mueller, W.F.; Santi, P.; Stolz, A. [National Superconducting Cyclotron Laboratory, Michigan State University, E. Lansing, Michigan 48824 (United States); Pellegrini, E. [Dept. of Physics and Astronomy, Michigan State University, E. Lansing, Michigan 48824 (United States); National Superconducting Cyclotron Laboratory, Michigan State University, E. Lansing, Michigan 48824 (United States); Arndt, O.; Kratz, K.-L.; Pfeiffer, B. [Institut fuer Kernchemie, Universitaet Mainz, Fritz-Strassmann Weg 2, D-55128 Mainz (Germany); VISTARS-Virtuelles Institut der Struktur der Kerne und nuklearer Astrophysik, Mainz (Germany); Reeder, P. [Richland, Washington 99352 (United States); Walters, W.B. [Dept. of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742 (United States); Aprahamian, A.; Woehr, A. [Joint Institute for Nuclear Astrophysics, and Institute for Structure and Nuclear Astrophysics, University of Notre Dame, Notre Dame, Indiana 46616 (United States)

2006-03-15

237

Electrochemical mineralization of the azo dye Acid Red 29 (Chromotrope 2R) by photoelectro-Fenton process.  

PubMed

The degradation of 100 mL of 244 mg L(-1) of the azo dye Acid Red 29 (AR29) has been studied by photoelectro-Fenton (PEF) using an undivided cell containing a boron-doped diamond (BDD) anode and an air-diffusion cathode under UVA irradiation. The effect of current density, concentration of catalytic Fe(2+) and pH on the process was examined. Quick decolorization and almost total mineralization were achieved due to the synergistic action of UVA light and oxidant hydroxyl radicals formed in the bulk from Fenton's reaction between electrogenerated H(2)O(2) at the cathode and added Fe(2+), as well as in the BDD surface from water oxidation. Optimum PEF conditions were found for 0.5-1.0 mM Fe(2+) and pH 3.0. Comparable electro-Fenton (EF) degradations in the dark yielded much poorer mineralization. The decay kinetics of AR29 followed a pseudo-first-order reaction with similar rate for EF and PEF. The azo dye disappeared much more rapidly than solution color, suggesting the formation of colored conjugated products with ?(max) similar to that of AR29. Ion-exclusion HPLC allowed the detection and quantification of tetrahydroxy-p-benzoquinone, oxalic, oxalacetic, tartronic, tartaric, oxamic, malonic and fumaric acids as intermediates in the PEF process. Oxalic acid, accumulated in large extent, was quickly destroyed by the efficient photolysis of Fe(III)-oxalate complexes with UVA light, whereas tartronic and oxamic acids were the most persistent byproducts because of the larger stability of their Fe(III) complexes. The mineralization of the initial N of the azo dye yielded NH(4)(+) ion and NO(3)(-) ion in smaller proportion. PMID:22854020

Almeida, Lucio Cesar; Garcia-Segura, Sergi; Arias, Conchita; Bocchi, Nerilso; Brillas, Enric

2012-07-31

238

Mechanism of post-segregational killing: translation of Hok, SrnB and Pnd mRNAs of plasmids R1, F and R483 is activated by 3'-end processing.  

PubMed Central

The gene systems hok/sok of R1, srnB of F and pnd of R483 mediate plasmid maintenance by killing of plasmid-free segregants. Translation of the very stable mRNAs encoding the killer proteins is regulated by small unstable antisense RNAs. The differential decay rates of the inhibitory antisense RNAs and the mRNAs encoding the killer proteins is the basis for the onset of killer mRNA translation in newborn plasmid-free segregants and the killing of these cells. We have suggested previously that this requires that the killer mRNAs occur in two forms. A translationally inactive form was proposed to be converted into a 3'-truncated, translationally active mRNA. In the presence of the antisense RNA, translation from this killer mRNA should be inhibited. In this communication we present in vivo and in vitro evidence that support this model. The requirement for 3'-processing for killer gene expression is demonstrated. By using in vitro techniques it is shown that full-length Hok mRNA is translationally inactive, whereas a 3'-end truncated version of the Hok mRNA is translationally active. In vitro secondary structure probing suggests that the 3'-end of the full-length Hok mRNA folds back onto the translational initiation region of the mok gene and thereby inhibits translation of the mRNA. By inference we conclude that the Pnd and SrnB mRNAs are regulated by a similar mechanism. Images

Thisted, T; Nielsen, A K; Gerdes, K

1994-01-01

239

The Saccharomyces cerevisiae small GTPase, Gsp1p/Ran, is involved in 3' processing of 7S-to-5.8S rRNA and in degradation of the excised 5'-A0 fragment of 35S pre-rRNA, both of which are carried out by the exosome.  

PubMed

Dis3p, a subunit of the exosome, interacts directly with Ran. To clarify the relationship between the exosome and the RanGTPase cycle, a series of temperature-sensitive Saccharomyces cerevisiae dis3 mutants were isolated and their 5.8S rRNA processing was compared with processing in strains with mutations in a S. cerevisiae Ran homologue, Gsp1p. In both dis3 and gsp1 mutants, 3' processing of 7S-to-5.8S rRNA was blocked at three identical sites in an allele-specific manner. In contrast, the 5' end of 5.8S rRNA was terminated normally in gsp1 and in dis3. Inhibition of 5.8S rRNA maturation in gsp1 was rescued by overexpression of nuclear exosome components Dis3p, Rrp4p, and Mtr4p, but not by a cytoplasmic exosome component, Ski2p. Furthermore, gsp1 and dis3 accumulated the 5'-A0 fragment of 35S pre-rRNA, which is also degraded by the exosome, and the level of 27S rRNA was reduced. Neither 5.8S rRNA intermediates nor 5'-A0 fragments were observed in mutants defective in the nucleocytoplasmic transport, indicating that Gsp1p regulates rRNA processing through Dis3p, independent of nucleocytoplasmic transport. PMID:11404326

Suzuki, N; Noguchi, E; Nakashima, N; Oki, M; Ohba, T; Tartakoff, A; Ohishi, M; Nishimoto, T

2001-06-01

240

The Dorsolateral Prefrontal Cortex Plays a Role in Self-Initiated Elaborative Cognitive Processing during Episodic Memory Encoding: rTMS Evidence.  

PubMed

During episodic memory encoding, elaborative cognitive processing can improve later recall or recognition. While multiple studies examined the neural correlates of encoding strategies, few studies have explicitly focused on the self-initiation of elaborative encoding. Repetitive transcranial magnetic stimulation (rTMS), a method which can transiently disrupt neural activity, was administered during an associative encoding task. rTMS was either applied to the left dorsolateral prefrontal cortex (DLPFC) or to the vertex (a control region not involved in memory encoding) during presentation of pairs of words. Pairs could be semantically related or not related. Two encoding instructions were given, either cueing participants to analyze semantic relationships (cued condition), or to memorize the pair without any specific strategy cues (the self-initiated condition). Participants filled out a questionnaire regarding their use of memory strategies and performed a cued-recall task. We hypothesized that if the DLPFC plays a role in the self-initiation of elaborative encoding we would observe a reduction in memory performance in the self-initiated condition, particularly for related. We found a significant correlation between the effects of rTMS and strategy use, only in the self-initiated condition with related pairs. High strategy users showed reduced performance following DLPFC stimulation, while low strategy users tended to show increased recall following DLPFC stimulation during encoding. These results suggest the left DLPFC may be involved in the self-initiation of memory strategy use, and individuals may utilize different neural networks depending on their use of encoding strategies. PMID:24040072

Hawco, Colin; Berlim, Marcelo T; Lepage, Martin

2013-09-05

241

The Dorsolateral Prefrontal Cortex Plays a Role in Self-Initiated Elaborative Cognitive Processing during Episodic Memory Encoding: rTMS Evidence  

PubMed Central

During episodic memory encoding, elaborative cognitive processing can improve later recall or recognition. While multiple studies examined the neural correlates of encoding strategies, few studies have explicitly focused on the self-initiation of elaborative encoding. Repetitive transcranial magnetic stimulation (rTMS), a method which can transiently disrupt neural activity, was administered during an associative encoding task. rTMS was either applied to the left dorsolateral prefrontal cortex (DLPFC) or to the vertex (a control region not involved in memory encoding) during presentation of pairs of words. Pairs could be semantically related or not related. Two encoding instructions were given, either cueing participants to analyze semantic relationships (cued condition), or to memorize the pair without any specific strategy cues (the self-initiated condition). Participants filled out a questionnaire regarding their use of memory strategies and performed a cued-recall task. We hypothesized that if the DLPFC plays a role in the self-initiation of elaborative encoding we would observe a reduction in memory performance in the self-initiated condition, particularly for related. We found a significant correlation between the effects of rTMS and strategy use, only in the self-initiated condition with related pairs. High strategy users showed reduced performance following DLPFC stimulation, while low strategy users tended to show increased recall following DLPFC stimulation during encoding. These results suggest the left DLPFC may be involved in the self-initiation of memory strategy use, and individuals may utilize different neural networks depending on their use of encoding strategies.

Hawco, Colin; Berlim, Marcelo T.; Lepage, Martin

2013-01-01

242

Fungal diversity in composting process of pig manure and mushroom cultural waste based on partial sequence of large subunit rRNA.  

PubMed

Fungal diversity during composting was investigated by culture-independent rDNA sequence analysis. Composting was carried out with pig manure and mushroom cultural waste using a field-scale composter (Hazaka system), and samples were collected at various stages. Based on partial sequence analysis of large subunit (LSU) ribosomal RNA (rRNA) and sequence identity values, a total of 12 different fungal species were found at six sampling sites; Geotrichum sp., Debaryomyces hansenii, Monographella nivalis, Acremonium strictum, Acremonium alternatum, Cladosporium sphaerospermum, Myriangium durosai, Pleurotus eryngii, Malassezia globosa, Malassezia restricta, Rhodotorula glutinis, and Fusarium sporotrichioides. Geotrichum sp. of the class Saccharomycetes was the most predominant fungal species throughout the composting process (185 out of a total of 236 identified clones, or 78.4%), followed by Acremonium strictum (7.6%), Monographella nivalis (5.1%), and Pleurotus eryngii (3.8%). The prevalence of Geotrichum sp. was the lowest (61.1%) at the beginning of composting, and then gradually increased to 92.5% after 10 days of composting. PMID:19734710

Cho, Kye Man; Kwon, Eun Ju; Kim, Sung Kyum; Kambiranda, Devaiah M; Math, Reukaradhya K; Lee, Young Han; Kim, Jungho; Yun, Han Dae; Kim, Hoon

2009-08-01

243

Development and evaluation of wastewater-treatment processes at the H-Coal site in Catlettsburg, Kentucky. Volume I. Design summary and R and D task identification  

SciTech Connect

The design of a mobile process development unit (PDU) for coal conversion wastewater treatment and an overview of the associated R and D program for its use are described. The PDU consists of three modular units, which can be arranged in various sequences: carbon adsorption, ozonation, and reverse osmosis. Each of the units has a nominal flow capacity of approx. 60 mL of wastewater feed per second (1 gpm). The feed to the PDU will be taken as a sidestream from the existing wastewater treatment system at the H-Coal site. It will have been processed through oil-water separation and distillation stripping, and can be taken both before and after bio-oxidation by an activated sludge process. The ozonation system experimental parameters are ozone contact time, ozone treatment rate, column pressure, and pH. The system will be analyzed as a continuous stirred tank reactor. The calculated results will include ozone reaction, treatment, and absorption rates, contaminant depletion and reaction rates, ozone absorption and contaminant removal efficiencies, and ozone volumetric mass-transfer coefficients. The carbon adsorption system will be operated to obtain bed-depth-service-time (BDST) data for various carbons and operating conditions. The BDST method will yield the rate of carbon exhaustion as well as the minimum depth of carbon required to remove contaminants. Reverse osmosis will be studied to measure dissolved solids rejection efficiency, permeate recovery, and fouling characteristics of various commercially available membranes.

Oswald, G.E.; Walker, J.F.; Brown, C.H.; Klein, J.A.; Genung, R.K.

1982-04-01

244

Implementing the r-process in metal-poor stars via black hole collapse and relevance to the light element enhancement  

NASA Astrophysics Data System (ADS)

Recent data compilations of abundances of Strontium and Barium in Extremely Metal Poor Stars show that large fluctuations exist in the ratio of the abundances of those elements. Two models exist for explaining those fluctuations, as well as the apparent truncation of data for those elements for stars having metallicity of [Fe/H] < -3.5. We study the factors that place upper limits on the logarithmic ratio [Sr/Ba] in the two models. A model has been developed in which the collapse of type II supernovae may produce a pronounced [Sr/Ba] enhancement in single-site r-process enriched stars. This model is consistent with galactic chemical constraints of light-element enrichment in metal-poor stars.

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

2013-07-01

245

Process R&D for CIS-Based Thin-Film PV: Annual Technical Report, 24 April 2002--23 April 2003  

SciTech Connect

During this subcontract period, predictability of Shell Solar Industries's CIS process was demonstrated by continuously executing the process while increasing throughput. Cumulative production for 2002 exceeded 1 MW - about twice the production rate for 2001. Average laminate efficiency for 2002 is 10.8% with a full width of only 12% of the average. Dramatic increases in line yield were achieved from improved production protocols and by addressing disparate special causes for process variation. Line yield increased from about 60% in 2000 to about 85% in 2002. NREL confirmed a champion 12.8% aperture-area conversion efficiency for a large-area (3626 cm2) CIS production module. Field failure mechanisms for prototype modules were clearly demonstrated. Additional circuit-plate or packaging process variables, although not as clearly established, were also found to affect long-term stability for pre-production modules. Significant progress was made toward developing a''glass/glass'' package that eliminates the TPAT backsheet for decreased cost, simplification of the package, and decreased operating temperature. Very promising preliminary results were demonstrated for edge seals developed in collaboration with the new NREL-sponsored National Thin-Film PV Module Reliability Team. Long-term outdoor stability has been demonstrated at NREL where {approx}30x30 cm and {approx}30x120 cm modules with multiple prototype package designs have undergone testing for over 14 years. The demonstrated high line yield is the major accomplishment. No one major process improvement was responsible for the yield improvements. Judicious application of manufacturing engineering disciplines such as SPC, analysis of variation, and design of experiments led to a clear definition of near-term yield issues. Dramatic improvements in yield were the result of improving production protocols and addressing disparate special causes for process variation. This major accomplishment supports 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.

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

2004-03-01

246

Direct and semi-direct capture in low-energy (n,{gamma}) reactions of neutron-rich tin isotopes and its implications for r-process nucleosynthesis  

SciTech Connect

The direct and semi-direct (DSD) components of the neutron capture cross sections are calculated for a series of tin isotopes by employing a single-particle potential (SPP) that gives a good reproduction of the known single-particle energies (SPEs) over a wide mass region. The results are compared with the Hauser-Feshbach (HF) contribution in the energy region of astrophysical interest. The calculated result shows that the HF component drops off rapidly for isotope {sup 132}Sn and toward more neutron-rich ones, whereas the DSD component decreases only smoothly and eventually becomes dominant. This result is consistent with those of previous studies, but the dependence of the DSD cross section on the target mass number is a feature of the present SPP that gives a smooth variation of SPEs. As a consequence, the direct portion of the DSD component gives the largest contribution to the total (n,{gamma}) cross section for neutron-rich isotopes below a few MeV. Therefore, the direct capture process modifies the astrophysical (n,{gamma}) reaction rates to a great extent. The semi-direct component, however, gives a negligible contribution to the astrophysical reaction rates, but its impact is significant above several MeV. The reason for the difference in isotopic dependence between the HF and DSD components is discussed, and its implication for r-process nucleosynthesis is given.

Chiba, S.; Koura, H.; Maruyama, T. [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Hayakawa, T. [Kansai Photon Science Institute, Japan Atomic Energy Agency, Kizu, Kyoto 619-0215 (Japan); National Astronomical Observatory, Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kawano, T. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Kajino, T. [National Astronomical Observatory, Osawa, Mitaka, Tokyo 181-8588 (Japan) and Department of Astronomy, School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2008-01-15

247

G.D.R. patent information system promotes the creation of modern high technologies as well as of complex innovation processes  

Microsoft Academic Search

The article explains the importance attached in the G.D.R. to patent information for formulating and solving R&D tasks. The G.D.R. Office for Inventions and Patents is responsible for the patent information system, which comprises information centres in industries, in various regions of the country and in the Office itself. Specialists engaged in R&D have easy access to patent literature, and

J. Hemmerling

1986-01-01

248

Role of Vascular Endothelial Growth Factor (VEGF) and VEGF-R Genotyping in Guiding the Metastatic Process in pT4a Resected Gastric Cancer Patients  

PubMed Central

In radically resected gastric cancer the possibility to predict the site of relapse could be clinically relevant for the selection of post-surgical management. We previously showed that specific tumour integrins genotypes are independently associated with either peritoneal or hematogenous metastases (ITGA and ITGV). Recently VEGF and VEGF-R polymorphisms have been demonstrated to potentially affect tumour angiogenesis and the metastatic process in gastric cancer. We then investigated the role of VEGFs and VEGF-R genotyping in determining either peritoneal carcinosis or hematogenous metastases in radically resected gastric cancer patients. Tumour genotyping for integrins (ITGA and ITGV) was also performed according to our previous findings. Genotyping for VEGF-A, VEGF-C, VEGFR-1,2,3 and ITGA and ITGV was carried out on pT4a radically resected gastric tumours recurring with either peritoneal-only carcinosis or hematogenous metastases. 101 patients fulfilled the inclusion criteria: 57 with peritoneal carcinomatosis only and 44 with hematogenous spread only. At multivariate analysis, intestinal histology and the AC genotype of rs699947 (VEGFA) showed to independently correlate with hematogenous metastases (p?=?0.0008 and 0.008 respectively), whereas diffuse histology and the AA genotype of rs2269772 (ITGA) independently correlated with peritoneal-only diffusion (p?=?<0.0001 and 0.03 respectively). Our results seem to indicate that combining information from genotyping of rs699947 (VEGFA, AC), rs2269772 (ITGA, AA) and tumour histology could allow clinicians to individuate gastric cancer at high risk for recurrence either with peritoneal or hematogenous metastases. The selection tool deriving from this analysis may allow an optimal use of the available treatment strategies in these patients.

Scartozzi, Mario; Loretelli, Cristian; Galizia, Eva; Mandolesi, Alessandra; Pistelli, Mirco; Bittoni, Alessandro; Giampieri, Riccardo; Faloppi, Luca; Bianconi, Maristella; Prete, Michela Del; Bianchi, Francesca; Belvederesi, Laura; Bearzi, Italo; Cascinu, Stefano

2012-01-01

249

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

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.

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

2013-01-01

250

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

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.

Lahmann, R.

1996-12-31

251

Ptc6 Is required for proper rapamycin-induced down-regulation of the genes coding for ribosomal and rRNA processing proteins in S. cerevisiae.  

PubMed

Ptc6 is one of the seven components (Ptc1-Ptc7) of the protein phosphatase 2C family in the yeast Saccharomyces cerevisiae. In contrast to other type 2C phosphatases, the cellular role of this isoform is poorly understood. We present here a comprehensive characterization of this gene product. Cells lacking Ptc6 are sensitive to zinc ions, and somewhat tolerant to cell-wall damaging agents and to Li(+). Ptc6 mutants are sensitive to rapamycin, albeit to lesser extent than ptc1 cells. This phenotype is not rescued by overexpression of PTC1 and mutation of ptc6 does not reproduce the characteristic genetic interactions of the ptc1 mutation with components of the TOR pathway, thus suggesting different cellular roles for both isoforms. We show here that the rapamycin-sensitive phenotype of ptc6 cells is unrelated to the reported role of Pt6 in controlling pyruvate dehydrogenase activity. Lack of Ptc6 results in substantial attenuation of the transcriptional response to rapamycin, particularly in the subset of repressed genes encoding ribosomal proteins or involved in rRNA processing. In contrast, repressed genes involved in translation are Ptc6-independent. These effects cannot be attributed to the regulation of the Sch9 kinase, but they could involve modulation of the binding of the Ifh1 co-activator to specific gene promoters. PMID:23704987

González, Asier; Casado, Carlos; Ariño, Joaquín; Casamayor, Antonio

2013-05-21

252

Dok-R Mediates Attenuation of Epidermal Growth Factor-Dependent Mitogen-Activated Protein Kinase and Akt Activation through Processive Recruitment of c-Src and Csk  

Microsoft Academic Search

Dok-R has previously been shown to associate with the epidermal growth factor receptor (EGFR) and become tyrosine phosphorylated in response to EGF stimulation. The recruitment of Dok-R to the EGFR, which is mediated through its phosphotyrosine binding (PTB) domain, results in attenuation of mitogen- activated protein kinase (MAPK) activation. Dok-R's ability to attenuate EGF-driven MAPK activation is independent of its

Paul Van Slyke; Mariano Loza Coll; Zubin Master; Harold Kim; Jorge Filmus; Daniel J. Dumont

2005-01-01

253

The R&D Process in the U.S. and Japan: Major findings from the RIETI-Georgia Tech inventor survey  

Microsoft Academic Search

This paper analyzes and compares the objective, the nature and the performance of R&D projects in the US and Japan, based on the first large scale systematic survey of inventors, focusing on the R&D projects yielding triadic patents. Major findings are the following. First, the projects for enhancing the existing business line of a firm account for a large share

NAGAOKA Sadao; John P. WALSH

2009-01-01

254

Non-Canonical Processing of Arabidopsis pri-miR319a/b/c Generates Additional microRNAs to Target One RAP2.12 mRNA Isoform  

PubMed Central

Arabidopsis miR319a/b/c primary transcripts are unusual due to the presence of a long stem and loop structure containing functional miR319a/b/c molecules. In our experiments carried out using high throughput sequencing (HTS), we have shown that additional microRNAs (miRNAs), miR319a.2/b.2/c.2 are generated from the upper part of the same hairpin structure. We have also found cognate miRNAa.2*/b.2*/c.2* to be present in the HTS results with a considerably lower number of reads. Northern hybridization revealed that miR319b.2 is mainly expressed in 35-day-old plant rosette leaves, as well as in stem and inflorescences of 42- and 53-day-old plants. Moreover, it carries multiple signatures of a functional miRNA, including as follows: (i) its biogenesis is HYL1-dependent; (ii) it is incorporated in a substantial amount into RISC complexes containing AGO1, AGO2, or AGO4 protein; (iii) 24 nt-long species of miR319b.2 have been found in inflorescences to be more abundant than 21 nt miR319b.2 species; (iv) it is present in various ratios to miR319b during plant development, which suggests the existence of a regulatory mechanism responsible for its biogenesis/processing; (v) there is an observed cross-species conservation of the miR319a/b/c stem nucleotide sequence extending beyond mature miRNA region; and (vi) all evidence suggests that intron-containing RAP2.12 mRNA isoform is the target for miR319b.2. All these features prompt us to claim miR319b.2 as a functional miRNA molecule.

Sobkowiak, Lukasz; Karlowski, Wojciech; Jarmolowski, Artur; Szweykowska-Kulinska, Zofia

2012-01-01

255

Introducing the fission-fusion reaction process: using a laser-accelerated Th beam to produce neutron-rich nuclei towards the N=126 waiting point of the r-process  

NASA Astrophysics Data System (ADS)

We propose to produce neutron-rich nuclei in the range of the astrophysical r-process (the rapid neutron-capture process) around the waiting point N=126 (Kratz et al. in Prog. Part. Nucl. Phys. 59:147, 2007; Arnould et al. in Phys. Rep. 450:97, 2007; Panov and Janka in Astron. Astrophys. 494:829, 2009) by fissioning a dense laser-accelerated thorium ion bunch in a thorium target (covered by a polyethylene layer, CH2), where the light fission fragments of the beam fuse with the light fission fragments of the target. Using the `hole-boring' (HB) mode of laser radiation pressure acceleration (RPA) (Robinson et al. in Plasma Phys. Control. Fusion 51:024004, 2009; Henig et al. in Phys. Rev. Lett. 103:245003, 2009; Tajima et al. in Rev. Accel. Sci. Technol. 2:221, 2009) using a high-intensity, short pulse laser, bunches of 232Th with solid-state density can be generated very efficiently from a Th layer (ca. 560 nm thick), placed beneath a deuterated polyethylene foil (CD2 with ca. 520 nm), both forming the production target. Th ions laser-accelerated to about 7 MeV/u will pass through a thin CH2 layer placed in front of a thicker second Th foil (both forming the reaction target) closely behind the production target and disintegrate into light and heavy fission fragments. In addition, light ions (d,C) from the CD2 production target will be accelerated as well to about 7 MeV/u, also inducing the fission process of 232Th in the second Th layer. The laser-accelerated ion bunches with solid-state density, which are about 1014 times more dense than classically accelerated ion bunches, allow for a high probability that generated fission products can fuse again when the fragments from the thorium beam strike the Th layer of the reaction target. In contrast to classical radioactive beam facilities, where intense but low-density radioactive beams of one ion species are merged with stable targets, the novel fission-fusion process draws on the fusion between neutron-rich, short-lived, light fission fragments from both beam and target. Moreover, the high ion beam density may lead to a strong collective modification of the stopping power in the target by `snowplough-like' removal of target electrons, leading to significant range enhancement, thus allowing us to use rather thick targets. Using a high-intensity laser with two beams with a total energy of 300 J, 32 fs pulse length and 3 ?m focal diameter, as, e.g. envisaged for the ELI-Nuclear Physics project in Bucharest (ELI-NP) ( http://www.eli-np.ro , 2010), order-of-magnitude estimates promise a fusion yield of about 103 ions per laser pulse in the mass range of A=180-190, thus enabling us to approach the r-process waiting point at N=126. First studies on ion acceleration, collective modifications of the stopping behaviour and the production of neutron-rich nuclei can also be performed at the upcoming new laser facility CALA (Center for Advanced Laser Applications) in Garching.

Habs, D.; Thirolf, P. G.; Gross, M.; Allinger, K.; Bin, J.; Henig, A.; Kiefer, D.; Ma, W.; Schreiber, J.

2011-05-01

256

The Putative NTPase Fap7 Mediates Cytoplasmic 20S Pre-rRNA Processing through a Direct Interaction with Rps14†  

PubMed Central

One of the proteins identified as being involved in ribosome biogenesis by high-throughput studies, a putative P-loop-type kinase termed Fap7 (YDL166c), was shown to be required for the conversion of 20S pre-rRNA to 18S rRNA. However, the mechanism underlying this function has remained unclear. Here we demonstrate that Fap7 is strictly required for cleavage of the 20S pre-rRNA at site D in the cytoplasm. Genetic depletion of Fap7 causes accumulation of only the 20S pre-rRNA, which could be detected not only in 43S preribosomes but also in 80S-sized complexes. Fap7 is not a structural component of 43S preribosomes but likely transiently interacts with them by directly binding to Rps14, a ribosomal protein that is found near the 3? end of the 18S rRNA. Consistent with an NTPase activity, conserved residues predicted to be required for nucleoside triphosphate (NTP) hydrolysis are essential for Fap7 function in vivo. We propose that Fap7 mediates cleavage of the 20S pre-rRNA at site D by directly interacting with Rps14 and speculate that it is an enzyme that functions as an NTP-dependent molecular switch in 18S rRNA maturation.

Granneman, Sander; Nandineni, Madhusudan R.; Baserga, Susan J.

2005-01-01

257

The putative NTPase Fap7 mediates cytoplasmic 20S pre-rRNA processing through a direct interaction with Rps14.  

PubMed

One of the proteins identified as being involved in ribosome biogenesis by high-throughput studies, a putative P-loop-type kinase termed Fap7 (YDL166c), was shown to be required for the conversion of 20S pre-rRNA to 18S rRNA. However, the mechanism underlying this function has remained unclear. Here we demonstrate that Fap7 is strictly required for cleavage of the 20S pre-rRNA at site D in the cytoplasm. Genetic depletion of Fap7 causes accumulation of only the 20S pre-rRNA, which could be detected not only in 43S preribosomes but also in 80S-sized complexes. Fap7 is not a structural component of 43S preribosomes but likely transiently interacts with them by directly binding to Rps14, a ribosomal protein that is found near the 3' end of the 18S rRNA. Consistent with an NTPase activity, conserved residues predicted to be required for nucleoside triphosphate (NTP) hydrolysis are essential for Fap7 function in vivo. We propose that Fap7 mediates cleavage of the 20S pre-rRNA at site D by directly interacting with Rps14 and speculate that it is an enzyme that functions as an NTP-dependent molecular switch in 18S rRNA maturation. PMID:16287850

Granneman, Sander; Nandineni, Madhusudan R; Baserga, Susan J

2005-12-01

258

Fate of R parity  

SciTech Connect

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.

Perez, Pavel Fileviez; Spinner, Sogee [Department of Physics, University of Wisconsin-Madison, Wisconsin 53706 (United States)

2011-02-01

259

Processing  

Microsoft Academic Search

In support of a model of language comprehension in which pragmatic biases are integrated with syntactic processing, we show that expectations about upcoming discourse continuations inuence the resolution of local structural ambiguity. An o-line sentence-completion study and an on- line self-paced reading study examined readers' expectations for high\\/low relative clause attachments following implicit-causality and non-implicit- causality verbs (John detests\\/babysits the

Hannah Rohde; Roger Levy; Andrew Kehler

260

Imp3 unfolds stem structures in pre-rRNA and U3 snoRNA to form a duplex essential for small subunit processing.  

PubMed

Eukaryotic ribosome biogenesis requires rapid hybridization between the U3 snoRNA and the pre-rRNA to direct cleavages at the A0, A1, and A2 sites in pre-rRNA that liberate the small subunit precursor. The bases involved in hybridization of one of the three duplexes that U3 makes with pre-rRNA, designated the U3-18S duplex, are buried in conserved structures: box A/A' stem-loop in U3 snoRNA and helix 1 (H1) in the 18S region of the pre-rRNA. These conserved structures must be unfolded to permit the necessary hybridization. Previously, we reported that Imp3 and Imp4 promote U3-18S hybridization in vitro, but the mechanism by which these proteins facilitate U3-18S duplex formation remained unclear. Here, we directly addressed this question by probing base accessibility with chemical modification and backbone accessibility with ribonuclease activity of U3 and pre-rRNA fragments that mimic the secondary structure observed in vivo. Our results demonstrate that U3-18S hybridization requires only Imp3. Binding to each RNA by Imp3 provides sufficient energy to unfold both the 18S H1 and the U3 box A/A' stem structures. The Imp3 unfolding activity also increases accessibility at the U3-dependent A0 and A1 sites, perhaps signaling cleavage at these sites to generate the 5' mature end of 18S. Imp4 destabilizes the U3-18S duplex to aid U3 release, thus differentiating the roles of these proteins. Protein-dependent unfolding of these structures may serve as a switch to block U3-pre-rRNA interactions until recruitment of Imp3, thereby preventing premature and inaccurate U3-dependent pre-rRNA cleavage and folding events in eukaryotic ribosome biogenesis. PMID:23980203

Shah, Binal N; Liu, Xin; Correll, Carl C

2013-08-26

261

R&M in conceptual aircraft design  

Microsoft Academic Search

Effectiveness of R&M (reliability and maintainability) in conceptual aircraft design is dependent on successful integration of R&M into the design process. The R&M process must not only integrate R&M tasks, but must also be integrated with other design and engineering functions. Once the process has been established, automation and tools required to support the process can be defined. An element

H. Sherrieb; J. T. Stracener

1992-01-01

262

rTMS evidence of different delay and decision processes in a fronto-parietal neuronal network activated during spatial working memory  

Microsoft Academic Search

The existence of a specific and widely distributed network for spatial working memory (WM) in humans, involving the posterior parietal cortex and the prefrontal cortex, is supported by a number of neuroimaging studies. We used a repetitive transcranial magnetic stimulation (rTMS) approach to investigate the temporal dynamics and the reciprocal interactions of the different areas of the parieto-frontal network in

Giacomo Koch; Massimiliano Oliveri; Sara Torriero; Giovanni A. Carlesimo; Patrizia Turriziani; Carlo Caltagirone

2005-01-01

263

The effects of exchange and interfacial reaction in two-phase systems on N.M.R. lineshapes and relaxation processes  

Microsoft Academic Search

The effects of molecular exchange between two immiscible fluid phases are of considerable importance when interpreting N.M.R. lineshapes and relaxation times in systems such as emulsions or coacervates, but have not been fully explored theoretically. In general the nuclei in each phase must be considered as belonging to distinct chemical species which are interchanged by chemical reaction localized at the

P. S. Belton; B. P. Hills

1988-01-01

264

C-C and C-Heteroatom Bond Dissociation Energies in CH3R?C(OH)2: Energetics for Photocatalytic Processes of Organic Diolates on TiO2 Surfaces  

SciTech Connect

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.

Wang, Tsang-Hsiu; Dixon, David A.; Henderson, Michael A.

2010-08-26

265

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...

266

Rates of R1 and R2 Retrotransposition and Elimination From the rDNA Locus of Drosophila melanogaster  

Microsoft Academic Search

R1 and R2 elements are non-LTR retrotransposons that insert specifically into the 28S rRNA genes of arthropods. The process of concerted evolution of the rDNA locus should give rise to rapid turnover of these mobile elements compared to elements that insert at sites throughout a genome. To estimate the rate of R1 and R2 turnover we have examined the insertion

Cesar E. Perez-Gonzalez; Thomas H. Eickbush

267

Viscosity of Gaseous R404A, R407C, R410A, and R507  

Microsoft Academic Search

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

H. Nabizadeh; F. Mayinger

1999-01-01

268

Neurocognitive effects of HF-rTMS over the dorsolateral prefrontal cortex on the attentional processing of emotional information in healthy women: An event-related fMRI study  

Microsoft Academic Search

Current evidence concerning the neurocircuitry underlying the interplay between attention and emotion is mainly correlational. We used high-frequency repetitive Transcranial Magnetic Stimulation (HF-rTMS) to experimentally manipulate activity within the right or left dorsolateral prefrontal cortex (DLPFC) of healthy women and examined changes in attentional processing of emotional information using an emotional modification of the exogenous cueing task during event-related fMRI.

Rudi De Raedt; Lemke Leyman; Chris Baeken; Peter Van Schuerbeek; Rob Luypaert; Marie-Anne Vanderhasselt; Udo Dannlowski

269

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

PubMed Central

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.

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

2008-01-01

270

Processing of defensive pigment in Aplysia californica: acquisition, modification and mobilization of the red algal pigment, r-phycoerythrin by the digestive gland.  

PubMed

The marine snail Aplysia californica obtains its purple defensive ink exclusively from the accessory photosynthetic pigment r-phycoerythrin, which is found in the red seaweeds of its diet. The rhodoplast digestive cell, one of three types of cell lining the tubules of the digestive gland, appears to be the site of catabolism of red algal chloroplasts (rhodoplasts) since thylakoid membranes, including phycobilisome-sized membrane-associated particles, were found within the large digestive vacuoles of this cell. Immunogold localization showed that there was a statistically significant occurrence of the red algal phycobilisome pigment r-phycoerythrin within these rhodoplast digestive vacuoles, but not in other compartments of this cell type (endoplasmic reticulum, mitochondria, nucleus) or in other tissues (abdominal ganglion). Immunogold analysis also suggested that the rhodoplast vacuole is the site for additional modification of r-phycoerythrin, which makes it non-antigenic: the chromophore is either cleaved from its biliprotein or the biliprotein is otherwise modified. The hemolymph had spectrographic absorption maxima typical of the protein-free chromophore (phycoerythrobilin) and/or r-phycoerythrin, but only when the animal had been feeding on red algae. Rhodoplast digestive cells and their vacuoles were not induced by the type of food in the diet: snails fed green seaweed and animals fed lettuce had characteristic rhodoplast cells but without the large membranous inclusions (rhodoplasts) or phycobilisome-like granules found in animals fed red seaweed. Two additional cell types lining the tubules of the digestive gland were characterized ultrastructurally: (1) a club-shaped digestive cell filled with electron-dense material, and (2) a triangular 'secretory' cell devoid of storage material and calcium carbonate. The following model is consistent with our observations: red algal rhodoplasts are freed from algal cells in the foregut and then engulfed by rhodoplast digestive cells in the tubules of the digestive diverticula, where they are digested in membrane-bound vacuoles; r-phycoerythrin is released from phycobilisomes on the rhodoplast thylakoids and chemically modified before leaving the digestive vacuole and accumulating in the hemolymph; the pigment then circulates throughout the body and is concentrated in specialized cells and vesicles of the ink gland, where it is stored until secreted in response to certain predators. PMID:9427675

Coelho; j

1998-01-01

271

SGNP: An Essential Stress Granule/Nucleolar Protein Potentially Involved in 5.8s rRNA Processing/Transport  

PubMed Central

Background Stress Granules (SG) are sites of accumulation of stalled initiation complexes that are induced following a variety of cellular insults. In a genetic screen for factors involved in protecting human myoblasts from acute oxidative stress, we identified a gene encoding a protein we designate SGNP (Stress Granule and Nucleolar Protein). Methodology/Principal Findings A gene-trap insertional mutagenesis screen produced one insertion that conferred resistance to sodium arsenite. RT-PCR/3? RACE was used to identify the endogenous gene expressed as a GFP-fusion transcript. SGNP is localized in both the cytoplasm and nucleolus and defines a non-nucleolar compartment containing 5.8S rRNA, a component of the 60S ribosomal subunit. Under oxidative stress, SGNP nucleolar localization decreases and it rapidly co-localizes with stress granules. The decrease in nucleolar SGNP following oxidative stress was accompanied by a large increase in nucleolar 5.8S rRNA. Knockdown of SGNP with shRNA increased global mRNA translation but induced growth arrest and cell death. Conclusions These results suggest that SGNP is an essential gene that may be involved in ribosomal biogenesis and translational control in response to oxidative stress.

Zhu, Chun-Hong; Kim, Jinyong; Shay, Jerry W.; Wright, Woodring E.

2008-01-01

272

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

PubMed Central

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

Sun, C; Woolford, J L

1994-01-01

273

Carrier Gas Dependence at Initial Processes for a-Plane AlN Growth on r-Plane Sapphire Substrates by Hydride Vapor Phase Epitaxy  

NASA Astrophysics Data System (ADS)

The influence of the carrier gas used during the thermal cleaning of r-plane sapphire substrates and the subsequent first AlN layer growth at 1050 °C on two-step growth of a-plane AlN layers by hydride vapor phase epitaxy (HVPE) was investigated. When hydrogen (H2) was used as the carrier gas, the decomposition of r-plane sapphire occurred during the thermal cleaning, and unintentional nitridation of the sapphire surface occurred at the beginning of the growth of the first AlN layer, which resulted in the occurrence of misoriented AlN grains in the second AlN layer grown at 1450 °C. When a mixture of H2 and nitrogen (N2) was used as the carrier gas, nitridation of the sapphire surface occurred during the thermal cleaning, which also resulted in the occurrence of misoriented AlN grains. A single-crystalline a-plane AlN layer free of misoriented grains could be obtained by using only N2 as the carrier gas during the thermal cleaning and the growth of the first AlN layer to prevent nitridation of the sapphire surface.

Tajima, Jumpei; Echizen, Chikashi; Togashi, Rie; Murakami, Hisashi; Kumagai, Yoshinao; Takada, Kazuya; Koukitu, Akinori

2011-05-01

274

Expression of miR1, miR133a, miR133b and miR206 increases during development of human skeletal muscle  

Microsoft Academic Search

Background  MicroRNAs (miRNAs) are small RNA molecules that post-transcriptionally regulate gene expression and have been shown to play\\u000a an important role during development. miR-1, miR-133a, miR-133b and miR-206 are expressed in muscle tissue and induced during\\u000a muscle cell differentiation, a process that directs myoblasts to differentiate into mature myotubes, which are organized into\\u000a myofibers. Although miR-1, miR-133a, miR-133b and miR-206 are

Andrie Koutsoulidou; Nikolaos P Mastroyiannopoulos; Denis Furling; James B Uney; Leonidas A Phylactou

2011-01-01

275

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

|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…

Lovett, Benjamin J.; Johnson, Theodore L.

2010-01-01

276

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

|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…

Sokhadze, Estate M.; El-Baz, Ayman; Baruth, Joshua; Mathai, Grace; Sears, Lonnie; Casanova, Manuel F.

2009-01-01

277

RNA polymerase II elongation factors Spt4p and Spt5p play roles in transcription elongation by RNA polymerase I and rRNA processing  

Microsoft Academic Search

Previous investigations into the mechanisms that control RNA Polymerase (Pol) I transcription have primarily focused on the process of transcription initiation, thus little is known regarding postinitiation steps in the transcription cycle. Spt4p and Spt5p are conserved throughout eukaryotes, and they affect elongation by Pol II. We have found that these two proteins copurify with Pol I and associate with

D. A. Schneider; S. L. French; Y. N. Osheim; A. O. Bailey; L. Vu; J. Dodd; J. R. Yates; A. L. Beyer; M. Nomura

2006-01-01

278

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

|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…

Snow, Richard E.; Jackson, Douglas N.

279

I N V I T E D N E L R E V E I W The neurobiology of pleasure, reward processes, addiction and their health implications  

Microsoft Academic Search

Modern science begins to understand pleasure as a potential component of salu- togenesis. Thereby, pleasure is described as a state or feeling of happiness and satisfaction resulting from an experience that one enjoys. We examine the neuro- biological factors underlying reward processes and pleasure phenomena. Further, health implications related to pleasurable activities are analyzed. With regard to possible negative effects

Tobias Esch; George B. Stefano

280

C1D and hMtr4p associate with the human exosome subunit PM\\/Scl-100 and are involved in pre-rRNA processing  

Microsoft Academic Search

The exosome is a complex of 30-50 exoribonucleases and RNA-binding proteins, which is involved in processing or degradation of different classes of RNA. Previously, the characterization of purified exosome complexes from yeast and human cells suggested that C1D and KIAA0052\\/hMtr4p are associated with the exosome and thus might regu- late its functional activities. Subcellular localization experiments demonstrated that C1D and

Geurt Schilders; Erwin van Dijk; Ger J. M. Pruijn

2007-01-01

281

Identification of cellulose synthase(s) in higher plants: sequence analysis of processive ?-glycosyltransferases with the common motif ’D, D, D35Q(R,Q)XRW‘  

Microsoft Academic Search

More than ten ?-glycosyltransferases are now recognized that have limited similarity to the amino acid sequence of cellulose\\u000a synthase from Acetobacter xylinum. Using hydrophobic cluster analysis (HCA), we recently identified two domains and putative\\u000a catalytic residues in the processive ?-glycosyltransferases. In this study, we have found expressed sequence tags (ESTs) from\\u000a higher plants (Arabidopsis thaliana, Brassica campestris, and Oryza sativa)

INDER M. SAXENA; R. MALCOLM BROWN

1997-01-01

282

Quantum-dot semiconductor optical amplifiers for high-bit-rate signal processing up to 160 Gb s-1 and a new scheme of 3R regenerators  

Microsoft Academic Search

This paper presents a theory and simulation of quantum-dot semiconductor optical amplifiers (SOAs) for high-bit-rate optical signal processing. The theory includes spatial isolation of quantum dots, carrier relaxation and excitation among the discrete energy states and the wetting layer, grouping of dots by their optical resonant frequency under the inhomogeneous broadening, and the homogeneous broadening of the single-dot gain, which

M. Sugawara; T. Akiyama; N. Hatori; Y. Nakata; H. Ebe; H. Ishikawa

2002-01-01

283

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

Microsoft Academic Search

In our previous study on individuals with autism spectrum disorder (ASD) (Sokhadze et al., Appl Psychophysiol Biofeedback\\u000a 34:37–51, 2009a) we reported abnormalities in the attention-orienting frontal event-related potentials (ERP) and the sustained-attention\\u000a centro-parietal ERPs in a visual oddball experiment. These results suggest that individuals with autism over-process information\\u000a needed for the successful differentiation of target and novel stimuli. In the

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

2010-01-01

284

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

PubMed

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

Pérez-González, C E; Eickbush, T H

2001-08-01

285

Fabrication and Testing of W&R MgB2 Coils Using CTFF Cu/MgB2 Wires and the Sol-Gel Insulation Process  

NASA Astrophysics Data System (ADS)

We have sol-gel insulated and characterized short samples of the Cu CTFF in Cu tube MgB2 wire with a view to fabricate the first US MgB2 coil from this conductor. The optimum heat treatment condition for this conductor was found to be half an hour at 700 °C under 4%H2-Ar gas flow. We have sol-gel insulated 25 meters of Cu/MgB2 wire with SnO2-ZrO2, layer wound the coil, impregnated with stycast and then tested it between 4.2 K and 30 K together with a sister sample which was heat treated with the coil. The coil had a Jc of 66190 A/cm2 at 4.2 K and 21428 A/cm2 at 20 K in its self field. This is almost identical to that of the sister sample when the self field effect is considered. This is very significant, as it demonstrate that with CTFF process which is readily scalable, one can produce any lengths of MgB2 conductor which would demonstrate the short sample Jc which is unheard of in the HTS conductors.

Hascicek, Y. S.; Aslanoglu, Z.; Arda, L.; Akin, Y.; Sumption, M. D.; Tomsic, M.

2004-06-01

286

Dissolution Enhancement of a Drug Exhibiting Thermal and Acidic Decomposition Characteristics by Fusion Processing: A Comparative Study of Hot Melt Extrusion and KinetiSol(R) Dispersing  

PubMed Central

In this study, hot melt extrusion (HME) and KinetiSol® Dispersing (KSD) were utilized to prepare dissolution-enhanced solid dispersions of Roche Research Compound A (ROA), a BCS class II drug. Preformulation characterization studies showed that ROA was chemically unstable at elevated temperatures and acidic pH values. Eudragit® L100-55 and AQOAT® LF (HPMCAS) were evaluated as carrier polymers. Dispersions were characterized for ROA recovery, crystallinity, homogeneity, and non-sink dissolution. Eudragit® L100-55 dispersions prepared by HME required the use of micronized ROA and reduced residence times in order to become substantially amorphous. Compositions containing HPMCAS were also prepared by HME, but an amorphous dispersion could not be obtained. All HME compositions contained ROA-related impurities. KSD was investigated as a method to reduce the decomposition of ROA while rendering compositions amorphous. Substantially amorphous, plasticizer free compositions were processed successfully by KSD with significantly higher ROA recovery values and amorphous character than those achieved by HME. A near-infrared chemical imaging analysis was conducted on the solid dispersions as a measure of homogeneity. A statistical analysis showed similar levels of homogeneity in compositions containing Eudragit® L100-55, while differences were observed in those containing HMPCAS. Non-sink dissolution analysis of all compositions showed rapid supersaturation after pH adjustment to approximately two to three times the equilibrium solubility of ROA, which was maintained for at least 24 h. The results of the study demonstrated that KSD is an effective method of forming dissolution-enhanced amorphous solid solutions in cases where HME is not a feasible technique.

DiNunzio, James C.; Bennett, Ryan C.; Brough, Chris; Miller, Dave A.; Ma, Hua; Williams, Robert O.; McGinity, James W.

2010-01-01

287

Synthesis of neoalkanes. [R/sub 1/R/sub 2/R/sub 3/CCOOH  

SciTech Connect

A process is described for the synthesis of an alkyl-substituted 1,1,1-trialkylalkane of the formula R/sub 1/R/sub 2/R/sub 3/CCH/sub 3/ by hydrogenation, wherein R/sub 1/, R/sub 2/ and R/sub 3/ are the same or different alkyl of 1-10 carbon atoms in the presence of a hydrogenation catalyst and hydrogen, the improvement which comprises hydrogenating a feed of a neoacid of the formula R/sub 1/R/sub 2/R/sub 3/CCOOH, at a temperature from about 325/sup 0/C to about 375/sup 0/C; a hydrogen feed rate of 1500 to 8000 m1/g catalyst/h; a neoacid feed rate of 0.2 to 4.9 mM/g catlyst/h and a hydrogen pressure of 35-140 Kg/cm/sup 2/ over a copper oxide/zinc oxide catalyst comprising 80-95% by weight of copper oxide/zinc oxide in an 8:1 to 1:1 weight ratio and 20-5% by weight alumina to obtain substantially complete conversion of the neoacid and recovering a product containing at least about 15 mol % yield of neoalkane based on the neoacid feed.

Butter, S.A.; Stoll, I.

1986-06-03

288

Condensation heat transfer and pressure drop characteristics of R-290, R-600a, R-134a and R-22 in horizontal tubes  

NASA Astrophysics Data System (ADS)

This paper presents the experimental results of condensation heat transfer coefficients of hydrocarbon (HC) refrigerants R-290 and R-600a, hydrochlorofluorocarbon (HCFC) refrigerant R-22, and hydrofluorocarbon (HFC) refrigerant R-134a in a horizontal double-pipe heat exchanger having pipe inner diameters of 10.07, 7.73, 6.54, and 5.80 mm. The condensation process experiments were conducted at mass flux of 35.5-210.4 kg/m2 s and condensation temperature of 40°C. The main results were summarized as follows: The average condensation heat transfer coefficients of R-290 and R-600a were higher than those of R-22 and R-134a. The pressure drops of the four refrigerants were in the order of R-600a > R-290 > R-134a > R-22. The pressure drops of R-600a, R-290, R-134a, and R-22 were approximately 6-15, 9.8-12.5, 4.3-6.7, and 2.1-4.6% higher, respectively, in the 10.7 mm diameter tubes compared to the 5.80 mm diameter tubes. Comparing the condensation heat transfer coefficients of our experimental results with those of other correlations, our experimental data in all the test tubes coincided best with that of Haraguchi et al.

Lee, Ho-Saeng; Son, Chang-Hyo

2010-05-01

289

The impact of firm participation in R&D programmes on R&D partnerships  

Microsoft Academic Search

R&D subsidies designed to encourage innovation efforts by firms may have intended and unintended effects on the way they organize their innovation process. We present empirical evidence on how R&D subsidies affect firms’ R&D cooperation strategies. In particular, we investigate whether receiving public R&D subsidies affect the probability that a firm will set up an R&D partnership with a public

Isabel Busom; Andrea Fernández-Ribas

2008-01-01

290

Rates of R1 and R2 retrotransposition and elimination from the rDNA locus of Drosophila melanogaster.  

PubMed

R1 and R2 elements are non-LTR retrotransposons that insert specifically into the 28S rRNA genes of arthropods. The process of concerted evolution of the rDNA locus should give rise to rapid turnover of these mobile elements compared to elements that insert at sites throughout a genome. To estimate the rate of R1 and R2 turnover we have examined the insertion of new elements and elimination of old elements in the Harwich mutation accumulation lines of Drosophila melanogaster, a set of inbred lines maintained for >350 generations. Nearly 300 new insertion and elimination events were observed in the 19 Harwich lines. The retrotransposition rate for R1 was 18 times higher than the retrotransposition rate for R2. Both rates were within the range previously found for retrotransposons that insert outside the rDNA loci in D. melanogaster. The elimination rates of R1 and R2 from the rDNA locus were similar to each other but over two orders of magnitude higher than that found for other retrotransposons. The high rates of R1 and R2 elimination from the rDNA locus confirm that these elements must maintain relatively high rates of retrotransposition to ensure their continued presence in this locus. PMID:12399390

Pérez-González, César E; Eickbush, Thomas H

2002-10-01

291

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...

292

Viscosity of gaseous R404A, R407C, R410A, and R507  

SciTech Connect

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.

Nabizadeh, H.; Mayinger, F.

1999-05-01

293

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

NASA Astrophysics Data System (ADS)

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.

Iihoshi, Masao

2011-02-01

294

Metabolism of fostamatinib, the oral methylene phosphate prodrug of the spleen tyrosine kinase inhibitor R406 in humans: contribution of hepatic and gut bacterial processes to the overall biotransformation.  

PubMed

The metabolism of the spleen tyrosine kinase inhibitor N4-(2,2-dimethyl-3-oxo-4-pyrid[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethyoxyphenyl)-2,4-pyrimidinediamine (R406) and its oral prodrug N4-(2,2-dimethyl-4-[(dihydrogenphosphonoxy)methyl]-3-oxo-5-pyrid[1,4]oxazin-6-yl)-5-fluoro-N2-(3,4,5-trimethyoxyphenyl)-2,4-pyrimidinediamine disodium hexahydrate (R788, fostamatinib) was determined in vitro and in humans. R788 was rapidly converted to R406 by human intestinal microsomes, and only low levels of R788 were observed in plasma of human subjects after oral administration of (14)C-R788. R406 was the major drug-related compound in plasma from human subjects, and only low levels of metabolites were observed in plasma. The plasma metabolites of R406 were identified as a sulfate conjugate and glucuronide conjugate of the para-O-demethylated metabolite of R406 (R529) and a direct N-glucuronide conjugate of R406. Elimination of drug-related material into the urine accounted for 19% of the administered dose, and the major metabolite in urine from all the human subjects was the lactam N-glucuronide of R406. On average, 80% of the total drug was recovered in feces. Two drug-related peaks were observed; one peak was identified as R406, and the other peak was identified as a unique 3,5-benzene diol metabolite of R406. The 3,5-benzene diol metabolite appeared to result from the subsequent O-demethylations and dehydroxylation of R529 by anaerobic gut bacteria because only R529 was converted to this metabolite after the in vitro incubation with human fecal samples. These data indicate that the major fecal metabolite of R406 observed in humans is a product of a hepatic cytochrome P450-mediated O-demethylation and subsequent O-demethylations and dehydroxylation by gut bacteria. PMID:20371637

Sweeny, David J; Li, Weiqun; Clough, Jeffrey; Bhamidipati, Somasekhar; Singh, Rajinder; Park, Gary; Baluom, Muhammad; Grossbard, Elliott; Lau, David T-W

2010-04-06

295

Comparative analysis of basic principles of computation of radio attenuation observed in recommended guideline ITU-R P.452 and ITU-R R.1546  

Microsoft Academic Search

The comparison of calculation of radio attenuation in the recommendations ITU-R P.452, and ITU-R R.1546 has been carried out. In the process of analysis the differences has been revealed: the first, calculates attenuation throughout the flight path in detail, and the second, uses approximized empirical curves. It follows that the recommended guideline ITU-R P.452 is for precise calculations, and ITU-R

M. A. Kolomicev; A. A. Mandryka

2010-01-01

296

Equations of State for Mixtures of R-32, R-125, R-134a, R-143a, and R-152a  

Microsoft Academic Search

Mixture models explicit in Helmholtz energy have been developed to calculate the thermodynamic properties of refrigerant mixtures containing R-32, R-125, R-134a, R143a, and R-152a. The Helmholtz energy of the mixture is the sum of the ideal gas contribution, the compressibility (or real fluid) contribution, and the contribution from mixing. The independent variables are the density, temperature, and composition. The model

Eric W. Lemmon; Richard T Jacobsen

2004-01-01

297

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

NASA Astrophysics Data System (ADS)

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.

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

298

Cycle performance study on R32\\/R125\\/R161 as an alternative refrigerant to R407C  

Microsoft Academic Search

This paper presents the new ternary non-azeotropic mixture of R32\\/R125\\/R161 as an alternative refrigerant to R407C. The physical properties of the ternary mixture are similar to those of R407C, and it is environmental friendly, that is, it has zero ozone-depletion potentials (ODP) and lower global warming potentials (GWP) than R407C. Theoretical cycle performances of R32\\/R125\\/R161 and R407C are calculated and

X. H. Han; Q. Wang; Z. W. Zhu; G. M. Chen

2007-01-01

299

Rolling 4R linkages  

Microsoft Academic Search

In this paper, a family of mobile 4R linkages is proposed to complete the rolling gait. They are derived from the general 4R four-bar linkage. The first subgroup of this family consists of three planar straight rolling 4R linkages: (1) the linkage driven by four active revolute joints, (2) the linkage driven by an arbitrary active revolute joint, and (3)

Chang-Huan Liu; Yan-An Yao; Rui-Ming Li; Yao-Bin Tian; Nan Zhang; Yuan-Yuan Ji; Fan-Zheng Kong

300

An R2R3-type transcription factor gene AtMYB59 regulates root growth and cell cycle progression in Arabidopsis  

Microsoft Academic Search

MYB proteins play important roles in eukaryotic organisms. In plants, the R1R2R3-type MYB proteins function in cell cycle control. However, whether the R2R3-type MYB protein is also involved in the cell division process remains unknown. Here, we report that an R2R3-type transcription factor gene, AtMYB59, is involved in the regulation of cell cycle progression and root growth. The AtMYB59 protein

Rui-Ling Mu; Yang-Rong Cao; Yun-Feng Liu; Gang Lei; Hong-Feng Zou; Yong Liao; Hui-Wen Wang; Wan-Ke Zhang; Biao Ma; Ji-Zhou Du; Ming Yuan; Jin-Song Zhang; Shou-Yi Chen

2009-01-01

301

Equations for the Thermal Conductivity of R-32, R-125, R-134a, and R-143a  

Microsoft Academic Search

At present hydrofluorocarbons (HFCs) such as R32, R-125, R-134a, and R-143a are widely used, and it is required to obtain accurate information of thermophysical properties, especially of the thermal conductivity of HFCs. In this paper new thermal conductivity equations for R-32, R-125, R134a, and R143a are proposed, applicable over a wide range of temperature and pressure including the critical region

J. Yata; Y. Ueda; M. Hori

2005-01-01

302

Hearings Before the General Subcommittee on Education...Ninety-First Congress, First Session on H.R. 8809...April 29 and 30, 1969. National Science Research Data Processing and Information Retrieval System. [Complete Text of the Hearings].  

ERIC Educational Resources Information Center

|Reported are the hearings held on April 29 and 30, 1969 before the General Subcommittee on Education of the U.S. House of Representatives on H.R. 8809, a bill to amend Title IX of the National Defense Education Act of 1958 to provide for the establishment of a national information retrieval system for scientific and technical information. The…

Congress of the U.S., Washington, DC. House Committee on Education and Labor.

303

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

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 2? 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 were calculated using the 2-D model to be 0.46 and 0.54, respectively. Infrared absorption spectra for (E)- and (Z)-R-316c were measured at 296 K and used to estimate their radiative efficiencies (REs) and GWPs; 100-year time-horizon GWPs of 4160 and 5400 were obtained for (E)- and (Z)-R-316c, respectively. Both isomers of R-316c are shown in this work to be long-lived ozone depleting substances and potent greenhouse gases. PMID:24079521

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

2013-10-17

304

MiR-1246  

PubMed Central

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.

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

2012-01-01

305

Helium-atom-scattering study of multiphonon processes on LiF(001){l_angle}100{r_angle} with temperature variation for specular and off-specular angles  

SciTech Connect

High-resolution inelastic He-atom-scattering experiments, employing a time-of-flight energy resolution technique, have been carried out on LiF(001){l_angle}100{r_angle} for a wide range of temperatures and for several different incident beam angles. A quantum-mechanical multiphonon theory is used to explain the observed inelastic background. Numerical calculations based on the theory produce good agreement with experiment.

Bishop, G.G.; Gillman, E.S.; Baker, J.; Hernandez, J.J.; Safron, S.A.; Skofronick, J.G. [Department of Physics, Department of Chemistry, and Center for Materials Science Research and Development (MARTECH), Florida State University, Tallahassee, Florida 32306 (United States); Weera, S.M.; Manson, J.R. [Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634 (United States)

1995-11-01

306

A Population Genetic Model for the Maintenance of R2 Retrotransposons in rRNA Gene Loci  

PubMed Central

R2 retrotransposable elements exclusively insert into the tandemly repeated rRNA genes, the rDNA loci, of their animal hosts. R2 elements form stable long-term associations with their host, in which all individuals in a population contain many potentially active copies, but only a fraction of these individuals show active R2 retrotransposition. Previous studies have found that R2 RNA transcripts are processed from a 28S co-transcript and that the likelihood of R2-inserted units being transcribed is dependent upon their distribution within the rDNA locus. Here we analyze the rDNA locus and R2 elements from nearly 100 R2-active and R2-inactive individuals from natural populations of Drosophila simulans. Along with previous findings concerning the structure and expression of the rDNA loci, these data were incorporated into computer simulations to model the crossover events that give rise to the concerted evolution of the rRNA genes. The simulations that best reproduce the population data assume that only about 40 rDNA units out of the over 200 total units are actively transcribed and that these transcribed units are clustered in a single region of the locus. In the model, the host establishes this transcription domain at each generation in the region with the fewest R2 insertions. Only if the host cannot avoid R2 insertions within this 40-unit domain are R2 elements active in that generation. The simulations also require that most crossover events in the locus occur in the transcription domain in order to explain the empirical observation that R2 elements are seldom duplicated by crossover events. Thus the key to the long-term stability of R2 elements is the stochastic nature of the crossover events within the rDNA locus, and the inevitable expansions and contractions that introduce and remove R2-inserted units from the transcriptionally active domain.

Eickbush, Thomas H.

2013-01-01

307

A population genetic model for the maintenance of R2 retrotransposons in rRNA gene loci.  

PubMed

R2 retrotransposable elements exclusively insert into the tandemly repeated rRNA genes, the rDNA loci, of their animal hosts. R2 elements form stable long-term associations with their host, in which all individuals in a population contain many potentially active copies, but only a fraction of these individuals show active R2 retrotransposition. Previous studies have found that R2 RNA transcripts are processed from a 28S co-transcript and that the likelihood of R2-inserted units being transcribed is dependent upon their distribution within the rDNA locus. Here we analyze the rDNA locus and R2 elements from nearly 100 R2-active and R2-inactive individuals from natural populations of Drosophila simulans. Along with previous findings concerning the structure and expression of the rDNA loci, these data were incorporated into computer simulations to model the crossover events that give rise to the concerted evolution of the rRNA genes. The simulations that best reproduce the population data assume that only about 40 rDNA units out of the over 200 total units are actively transcribed and that these transcribed units are clustered in a single region of the locus. In the model, the host establishes this transcription domain at each generation in the region with the fewest R2 insertions. Only if the host cannot avoid R2 insertions within this 40-unit domain are R2 elements active in that generation. The simulations also require that most crossover events in the locus occur in the transcription domain in order to explain the empirical observation that R2 elements are seldom duplicated by crossover events. Thus the key to the long-term stability of R2 elements is the stochastic nature of the crossover events within the rDNA locus, and the inevitable expansions and contractions that introduce and remove R2-inserted units from the transcriptionally active domain. PMID:23326244

Zhou, Jun; Eickbush, Michael T; Eickbush, Thomas H

2013-01-10

308

The Rh Phenotype r’r’ in Polynesians  

Microsoft Academic Search

Since 1970, 19 persons with the r’r’ phenotype have been detected at the Auckland Blood Transfusion Centre. All have been Maoris or Pacific Islanders. This study reports the detailed serological investigations on 11 r’r’ samples. No evidence was found for the presence of the Du antigen, and there was no evidence that the Polynesian r’ was related to the Negroid

C. J. Lyne; P. L. Clark; M. A. Lyne; D. G. Woodfield

1985-01-01

309

Arformoterol: (R,R)-eformoterol, (R,R)-formoterol, arformoterol tartrate, eformoterol-sepracor, formoterol-sepracor, R,R-eformoterol, R,R-formoterol.  

PubMed

Sepracor in the US is developing arformoterol [R,R-formoterol], a single isomer form of the beta(2)-adrenoceptor agonist formoterol [eformoterol]. This isomer contains two chiral centres and is being developed as an inhaled preparation for the treatment of respiratory disorders. Sepracor believes that arformoterol has the potential to be a once-daily therapy with a rapid onset of action and a duration of effect exceeding 12 hours. In 1995, Sepracor acquired New England Pharmaceuticals, a manufacturer of metered-dose and dry powder inhalers, for the purpose of preparing formulations of levosalbutamol and arformoterol. Phase II dose-ranging clinical studies of arformoterol as a longer-acting, complementary bronchodilator were completed successfully in the fourth quarter of 2000. Phase III trials of arformoterol began in September 2001. The indications for the drug appeared to be asthma and chronic obstructive pulmonary disease (COPD). However, an update of the pharmaceutical product information on the Sepracor website in September 2003 listed COPD maintenance therapy as the only indication for arformoterol. In October 2002, Sepracor stated that two pivotal phase III studies were ongoing in 1600 patients. Sepracor estimates that its NDA submission for arformoterol, which is projected for the first half of 2004, will include approximately 3000 adult subjects. Sepracor stated in July 2003 that it had completed more than 100 preclinical studies and initiated or completed 15 clinical studies for arformoterol inhalation solution for the treatment of bronchospasm in patients with COPD. In addition, Sepracor stated that the two pivotal phase III studies in 1600 patients were still progressing. In 1995, European patents were granted to Sepracor for the use of arformoterol in the treatment of asthma, and the US patent application was pending. PMID:14725487

2004-01-01

310

A holistic abundance analysis of r-rich stars  

NASA Astrophysics Data System (ADS)

The chemical abundances of metal-poor stars are an excellent test bed by which to set new constraints on models of neutron-capture processes at low metallicity. Some r-process-rich (hereafter r-rich) metal-poor stars, such as HD 221170, show an overabundance of the heavier neutron-capture elements and excesses of lighter neutron-capture elements. The study of these r-rich stars could give us a better understanding of weak and main r-process nucleosynthesis at low metallicity. Based on conclusions from the observation of metal-poor stars and neutron-capture element nucleosynthesis theory, we set up a model to determine the relative contributions from weak and main r-processes to the heavy-element abundances in metal-poor stars. Using this model, we find that the abundance patterns of light elements for most sample stars are close to the pattern of weak r-process stars, and those of heavier neutron-capture elements very similar to the pattern of main r-process stars, while the lighter neutron-capture elements can be fitted by the mixing of weak and main r-process material. The production of weak r-process elements appears to be associated with the light elements, while the production of main r-process elements is almost decoupled from that of the light elements. We compare our results with the observed data at low metallicities, showing that the predicted trends are in good agreement with the observed trends, at least for the metallicity range [Fe/H] < -2.1. For most sample stars, the abundance patterns of both neutron-capture elements and light elements could be best explained by a star formed in a molecular cloud that has been polluted by both weak and main r-process material.

Zhang, Jiang; Cui, Wenyuan; Zhang, Bo

2010-12-01

311

R type anion channel  

PubMed Central

Plant genomes code for channels involved in the transport of cations, anions and uncharged molecules through membranes. Although the molecular identity of channels for cations and uncharged molecules has progressed rapidly in the recent years, the molecular identity of anion channels has lagged behind. Electrophysiological studies have identified S-type (slow) and R-type (rapid) anion channels. In this brief review, we summarize the proposed functions of the R-type anion channels which, like the S-type, were first characterized by electrophysiology over 20 years ago, but unlike the S-type, have still yet to be cloned. We show that the R-type channel can play multiple roles.

Diatloff, Eugene; Peyronnet, Remi; Colcombet, Jean; Thomine, Sebastien; Barbier-Brygoo, Helene

2010-01-01

312

Behavioural additionality of R&D subsidies: A learning perspective  

Microsoft Academic Search

The use of R&D grants as a policy instrument has been motivated by economic arguments of market failure. Neo-classical econometric studies have analysed the additionality of one Euro of subsidies on both the investments of companies in the R&D process and the output of that R&D process. More recently, behavioural additionality has been launched as a third form of additionality.

Bart Clarysse; Mike Wright; Philippe Mustar

2009-01-01

313

Interactions of miR-323/miR-326/miR-329 and miR-130a/miR-155/miR-210 as prognostic indicators for clinical outcome of glioblastoma patients  

PubMed Central

Background Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor with poor clinical outcome. Identification and development of new markers could be beneficial for the diagnosis and prognosis of GBM patients. Deregulation of microRNAs (miRNAs or miRs) is involved in GBM. Therefore, we attempted to identify and develop specific miRNAs as prognostic and predictive markers for GBM patient survival. Methods Expression profiles of miRNAs and genes and the corresponding clinical information of 480 GBM samples from The Cancer Genome Atlas (TCGA) dataset were downloaded and interested miRNAs were identified. Patients’ overall survival (OS) and progression-free survival (PFS) associated with interested miRNAs and miRNA-interactions were performed by Kaplan-Meier survival analysis. The impacts of miRNA expressions and miRNA-interactions on survival were evaluated by Cox proportional hazard regression model. Biological processes and network of putative and validated targets of miRNAs were analyzed by bioinformatics. Results In this study, 6 interested miRNAs were identified. Survival analysis showed that high levels of miR-326/miR-130a and low levels of miR-323/miR-329/miR-155/miR-210 were significantly associated with long OS of GBM patients, and also showed that high miR-326/miR-130a and low miR-155/miR-210 were related with extended PFS. Moreover, miRNA-323 and miRNA-329 were found to be increased in patients with no-recurrence or long time to progression (TTP). More notably, our analysis revealed miRNA-interactions were more specific and accurate to discriminate and predict OS and PFS. This interaction stratified OS and PFS related with different miRNA levels more detailed, and could obtain longer span of mean survival in comparison to that of one single miRNA. Moreover, miR-326, miR-130a, miR-155, miR-210 and 4 miRNA-interactions were confirmed for the first time as independent predictors for survival by Cox regression model together with clinicopathological factors: Age, Gender and Recurrence. Plus, the availability and rationality of the miRNA-interaction as predictors for survival were further supported by analysis of network, biological processes, KEGG pathway and correlation analysis with gene markers. Conclusions Our results demonstrates that miR-326, miR-130a, miR-155, miR-210 and the 4 miRNA-interactions could serve as prognostic and predictive markers for survival of GBM patients, suggesting a potential application in improvement of prognostic tools and treatments.

2013-01-01

314

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

PubMed

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

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

2012-08-01

315

R-values  

SciTech Connect

I'll try to keep this short and simple. R{sub LANL} = (beta cpm of X{sub exp} on system 'A')/ (beta cpm of {sup 99}Mo{sub exp} on system 'A')/ (beta cpm of X on system 'A', from thermal on {sup 235}U)/ (beta cpm of {sup 99}Mo on system 'A', from thermal on {sup 235}U). As I understand it, the above equation is the historical (as well as current) way of determining R-values using data from beta counting at LANL. The ratio in the denominator, a little 'r', is the 'baseline' or 'calibration' value for a specific beta detector. Over time, if the detector 'drifts' one would see a variation in this 'r' during a thermal calibration measurement. This baseline is what LANL likes to track to monitor specific detector performance - this is not relevant to LLNL where gamma detection is used for determining R-values. LANL states that uncertainty is only dependent upon the count statistics for the isotopes measured. If one tries to convert this to an atom basis, the uncertainties will increase due to the incorporation of the uncertainties in the nuclear data used to convert the cpm to atoms. LLNL switched to gamma detection methods in the 1970s thus replacing our beta counting effort. The equation below is how we have since determined R-values. The numerator ratios atom values of isotopes that are determined by measuring gamma cpm (usually? using several peaks per isotope) and then converting to particle decay in dpm using detector efficiency for each peak and the appropriate branch ratio for each gamma emission. Isotope decay is then converted to atoms using specific activity, mass or volume?, and Avogadro's number. The denominator is simply the ratio of published, cumulative fission product chain yields for isotopes produced in a thermal irradiation on 235U - values of England & Ryder are used by LLNL for the NTNF program. Uncertainties in LLNL R-values are dependent upon gamma counting statistics as well as the nuclear data for each isotope. R{sub LLNL} = (Atoms of X{sub exp})/(Atoms of {sup 99}Mo{sub exp})/(Cumulative Fission Chain Yield of X, from thermal on {sup 235}U)/(Cumulative Fission Chain Yield of {sup 99}Mo, from thermal on {sup 235}U). The next page tabulates fission chain yields and 'atoms per gram' amounts measured in a recent NTNF Thermal Calibration. The R-values in the table are calculated using the LLNL method of determining R. The measure of success is demonstrated by how close to 1.00 the R-value is when determined during a Thermal Calibration. A value of 1.00 is the desired value. In the example below, only four isotopes lie outside of 1.00 by more than 3 percent. These are the four isotopic measurements that obviously need to be improved.

Roberts, K

2009-03-03

316

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

SciTech Connect

Hydrologic information is essential for environmental efforts at Los Alamos National Laboratory. Testing at new characterization wells being drilled to the regional aquifer (''R wells'') to improve the conceptual hydrogeologic model of the Pajarito Plateau is providing such information. Drilling has been by air-rotary casing-advance or open-hole methods. Most wells are completed with multiple screens. After their construction, wells were rigorously developed by wire-brushing, bailing, followed by surging, swabbing, or jetting, and finally by pumping. These methods are effective based on field-parameter measurements and comparison of results of hydrologic testing at well R-31 before and after complete well development. We conducted field tests on various zones of saturation penetrated by the R wells to collect data needed for determining hydraulic properties. This document provides details of the design and execution of testing as well as an analysis of data for five of the new wells: R-9i, R-13, R-19, R-22, and R-31. One well was evaluated by a pumping test (R-13), another was evaluated by both straddle-packer/injection and pumping tests (R-9i), and the rest were evaluated by injection tests alone (R-19, R-22, R-31). Testing was constrained by the regional setting (complex geology and multiple zones of saturation) and well construction (multiscreen completion and the small diameter of the production casing). Packers are required for testing multiscreen wells. The small diameter of the production casing not only precludes the use of a slugger but also limits the capacity of pumps that can be used in testing, especially for the depths involved in the R wells. For example, pumping at a maximum rate of 19 gallons per minute did not significantly stress the regional aquifer at R-13. Although not slug tests, the injection tests are comparable in several ways, and analysis of data by slugtest methods is appropriate. Despite constraints, the results obtained appear valid based on (1) the care taken during test implementation and data analysis, (2) comparison of results for initial and repeated tests obtained by the same analytical method, (3) comparison of results obtained for a given test by different analytical methods, (4) comparison of results with values determined by geophysical logging in the wells and pumping tests of the same geologic units elsewhere on the plateau, and (5) comparison with hydraulic properties commonly reported for similar geologic materials outside the area. Significant contributions of this report are not only the documentation of test design, implementation, and analysis but also a comprehensive table showing the distribution of hydraulic properties for the saturated geologic units tested beneath the Pajarito Plateau. We also offer several recommendations based on testing to date. Placing screens across the water table and geologic contacts as well as employing oversized filter packs hinders testing and should be avoided. In addition, we recommend that future testing include some alternative designs and methods. Multiple methods and routine repeat testing for a given screened interval would permit comparison of results.

W.J. Stone; S. McLin

2003-03-01

317

BAM R46: Mineral Oil  

Center for Food Safety and Applied Nutrition (CFSAN)

... Pesticide Analytical Manual (PAM). -. BAM R46: Mineral Oil. January 2001. Bacteriological Analytical Manual. R46 Mineral Oil. ... More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

318

BAM R12: Catalase Test  

Center for Food Safety and Applied Nutrition (CFSAN)

... Pesticide Analytical Manual (PAM). -. BAM R12: Catalase Test. January 2001. Bacteriological Analytical Manual. R12 Catalase Test. ... More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

319

R.E.M.  

NSDL National Science Digital Library

The members of the Internet mailing list "murmur" and newsgroup rec.music.rem have created a home page dedicated to the music of the group R.E.M. Also includes a nice collection of links to other music sources on the Web.

320

Gautam?R. Desiraju.  

PubMed

"Chemistry is fun because it is an assault on the senses! My favorite quote is 'To strive, to seek, to find, and not to yield' from Tennyson's poem 'Ulysses' …?" This and more about Gautam?R. Desiraju can be found on page 10152. PMID:23649663

2013-05-06

321

Sampling Distribution of r  

NSDL National Science Digital Library

This page, created by Richard Lowry of Vassar College, generates a graph of the sampling distribution of r, the Pearson correlation coefficient. Upon opening, the applet prompts for sample size greater than 6. The applet also displays the probabilities associated with the distribution.

Lowry, Richard

2009-10-13

322

Phototype plant for Nuclear Process Heat (NPH), reference phase. R and D work on Hydrogenated Coal Gasification (HCG). Further operation of semi-industrial plant for hydrogenated coal gasification  

NASA Astrophysics Data System (ADS)

In view of a scale up, leading to a commercial HCG, futher R and D work was performed on the 100 kg C/hr prototype plant. The inclined tube for feeding coal into the fluidized bed, the raw gas/hydrogenation gas heat exchanger, and the modified hydrogen source were tested. Influence on carbon gasification efficiency of dimension of coal particles, humidity of coal, hydrogen content of gasification gas, introduction place of coal in gasifier, height of fluidized bed, and ash content of coal were studied. The plant was operated for 19,400 hr, of which more than 7400 hr under gasification conditions. Carbon gasification rates up to 82% with methane content up to 48% were obtained.

Fladerer, R.; Schrader, L.

1982-07-01

323

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

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.

NONE

1997-03-01

324

MiR-221 and miR-130a regulate lung airway and vascular development.  

PubMed

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

Mujahid, Sana; Nielsen, Heber C; Volpe, MaryAnn V

2013-02-08

325

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

PubMed Central

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.

Mujahid, Sana

2013-01-01

326

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

Microsoft Academic Search

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

Sachiko Yoshie; Naohiro Noda; Tomoko Miyano; Satoshi Tsuneda; Akira Hirata; Yuhei Inamori

2001-01-01

327

National Science Research Data Processing and Information Retrieval System; Hearings before the General Subcommittee on Education ... Ninety-First Congress, First Session on H.R. 8809 ... April 29 and 30, 1969.  

ERIC Educational Resources Information Center

|Testimony given by Dr. John Rothman, Manager of Information Services, New York Times, before the General Subcommittee on Education ... describes the information retrieval system of the New York Times. He describes how the system will process material efficiently and economically, store it securely and in proper order, and make it available via…

Congress of the U.S., Washington, DC. House Committee on Education and Labor.

328

R&D as a technology engine  

Microsoft Academic Search

An economic model that takes knowledge, technology and capital, as prime production factors is used to interpret the importance of technology. The model defines technology and its value, discriminating from capital thus identifying R & D as the major technology production process. It also suggests that there is a default tendency, in every firm, to technology impoverishment and capital affluence.

A. S. C. Fernandes

2002-01-01

329

DEGASIFICATION OF NITROGEN FROM SANTOWAX R  

Microsoft Academic Search

The rate of degasificatlon of Nâ from monisopropyl diphenyl and ; from Santowax R was studied to determine the effects of various parameters on the ; vacuum degasification process. The effects of pressure, temperature, feed rate, ; and spray nozzle type and size were determined. (W.L.H.) 23b0 The moderating ; properties of organic coolants are directly related to the hydrogen

G. W. Corporales; P. R. Benson

1959-01-01

330

R-Factor  

NSDL National Science Digital Library

The amount of energy used in a home is greatly impacted by the type of materials used in constructing the home. In particular, the thermal conductivity of the materials will affect how quickly heat is allowed to enter or leave the home. In this hands-on activity, students will measure the ability of various materials to resist heat flow (R-factor) by placing a light bulb inside boxes made of the materials and monitoring the temperatures both inside and outside.

Pratte, John

2008-12-11

331

Affine processes are regular  

Microsoft Academic Search

We show that stochastically continuous, time-homogeneous affine processes on the canonical state space $${\\\\mathbb{R}_{\\\\geq 0}^m \\\\times \\\\mathbb{R}^n}$$ are always regular. In the paper of Duffie et al. (Ann Appl Probab 13(3):984–1053, 2003) regularity was used as a crucial\\u000a basic assumption. It was left open whether this regularity condition is automatically satisfied for stochastically continuous\\u000a affine processes. We now show that the

Martin Keller-Ressel; Walter Schachermayer; Josef Teichmann

2009-01-01

332

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

SciTech Connect

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 between the Puye fanglomerate and unassigned pumiceous units. The specific capacity analysis of a 12 minute pumping test indicates that the Puye fanglomerates near the R-13 screen have a T of 5269 ft{sup 2}/day and correspond to a hydraulic conductivity (K) of 17.6 ft/day based on a saturated thickness of 300 ft. Characterization well R-19 is located east of firing site IJ in Technical Area (TA) 36 on the mesa between Three-mile and Potrillo Canyons. It was completed at a depth of 1885 ft bgs in April 2000. This well was constructed with two screens positioned above the regional water table and five screens positioned below the regional water table. Only the bottom two screens were tested. Screen 6 is completed at about 1727-1734 ft bgs in Puye fanglomerate, and screen 7 is completed at about 1832-1849 ft bgs in Puye fanglomerate. Specific capacity analysis of the screen 6 data suggests that T is about 6923 ft{sup 2}/day and corresponds to a K of 18.6 ft/day based on a saturated thickness of 373 ft. Specific capacity analysis of the screen 7 data suggests that T is about 8179 ft{sup 2}/day and corresponds to a K of 22.0 ft/day based on a saturated thickness of 373 ft. Characterization well R-22 is located on Mesita del Buey between Canada del Buey and Pajarito Canyons immediately east of Material Disposal Area (MDA) G in TA-54. It was completed at a depth of 1489 ft bgs in October 2000. This well was constructed with five screens positioned at or below the regional water table; however, only screens 2-5 were tested. Screen 1 is completed at the regional water table at about 872-914 ft bgs in Cerros del Rio basalt. Screen 2 is completed at about 947-989 ft bgs in Cerros del Rio basalt. Screen 3 is completed at about 1272-1279 ft bgs in Puye fanglomerate. Screen 4 is completed at about 1378-1452 ft bgs in older basalt. Screen 5 is completed at about 1447-1452 ft bgs in older fanglomerate. Bouwer-Rice analyses of the injection-test recovery data suggest K values of 0.04, 0.32, 0.54, and 0.27 ft/day for screens 2, 3, 4, and 5, respectively. These values correspond to

S.G.McLin; W.J. Stone

2004-06-01

333

Assessment of Advanced Coal Gasification Processes.  

National Technical Information Service (NTIS)

A technical assessment of the following advanced coal gasification processes is presented: high throughput gasification (HTG) process; single stage high mass flux (HMF) processes; (CS/R) hydrogasification process; and the catalytic coal gasification (CCG)...

J. Mccarthy J. Ferrall T. Charng J. Houseman

1981-01-01

334

Measurements of the surface tension of three refrigerants, R 22, R 115, and R 502  

SciTech Connect

The surface tension was measured on three fluorocarbon refrigerants, R 22 (chlorodifluoromethane, CHCLF/sub 2/), R 115 (chloropentafluoroethane, CCLF/sub 2/CF/sub 3/), and R 502 (azeotropic mixture of 48.9 wt % R 22 and 51.1 wt % R 115), by using the capillary rise method. The results cover the range of temperatures from 273 K to a temperature close to the critical point of each substance. The uncertainty of surface tension measurements was estimated to be less than +-0.16 mN/m. For R 115 and R 502, van der Waals type correlations were developed based on the present results.

Okada, M.; Arima, T.; Hattori, M.; Watanabe, K.

1988-10-01

335

The R2 retrotransposon RNA families.  

PubMed

Analysis of the R2 retrotransposons from multiple silkmoth and fruitfly species have revealed three segments that contain conserved RNA secondary structures. These conserved structures play important roles in the propagation of the R2 element, including R2 RNA processing and transposon integration into the host genome as well as a likely role in translation. Two of the structured regions comprise protein binding sites: one is located in the 3' UTR and the other is in the 5' UTR close to the putative start of the R2 open reading frame (ORF). The 3' structure was deduced from chemical mapping and sequence comparison. The 5' structure was determined using a combination of chemical mapping, oligonucleotide binding, NMR and sequence analysis and contains an unusual pseudoknot structure. The third structure occurs at the 5' end of the R2 RNA and is responsible for self-cleavage of the 5' end of the element from a 28S ribosomal RNA co-transcript. A structure for this fragment was proposed based on motif searching and sequence comparison. There is remarkable similarity in sequence and structure to the hepatitis delta virus (HDV) ribozyme. Seed alignments for the 5' structure and the R2 ribozyme, containing representative sequences and consensus structures, have been submitted to the Rfam database. PMID:21734471

Moss, Walter N; Eickbush, Danna G; Lopez, Michael J; Eickbush, Thomas H; Turner, Douglas H

2011-07-07

336

Vapour-liquid equilibrium of ternary mixtures of the refrigerants R32, R125 and R134a  

Microsoft Academic Search

Ternary mixtures of R32, R125 and R134a of different compositions are recommended for replacing refrigerants R22 and R502. As a prerequisite for reliably calculating vapour pressure and phase equilibria of ternary mixtures within the relevant range of temperature and composition, VLE data of the three binary systems R32\\/R134a, R125\\/R134a and R32\\/R125 have been measured from ?70°C up to the critical

M Nagel; K Bier

1995-01-01

337

R3 Fluids  

NASA Astrophysics Data System (ADS)

The current paper is aimed at getting more insight on three main points concerning large-scale astrophysical systems, namely: (i) formulation of tensor virial equations from the standpoint of analytical mechanics; (ii) investigation on the role of systematic and random motions with respect to virial equilibrium configurations; (iii) determination of extent to which systematic and random motions are equivalent in flattening or elongating the shape of a mass distribution. The tensor virial equations are formulated regardless of the nature of the system and its constituents, by generalizing and extending a procedure used for the scalar virial equations in presence of discrete subunits (Landau and Lifchitz 1966). In particular, the self potential-energy tensor is shown to be symmetric with respect to the exchange of the indices, (E_{pot})_{pq}= (E_{pot})_{qp}. Then the results are extended to continuous mass distributions. The role of systematic and random motions in collisionless, ideal, self-gravitating fluids is analysed in detail including radial and tangential velocity dispersion on the equatorial plane, and the related mean angular velocity, overline{?}, is conceived as a figure rotation. R3 fluids are defined as ideal, self-gravitating fluids in virial equilibrium, with systematic rotation around a principal axis of inertia, taken to be x_3. The related virial equations are written in terms of the moment of inertia tensor, I_{pq}, the self potential-energy tensor, (E_{pot})_ {pq}, and the generalized anisotropy tensor, ?_{pq} (Caimmi and Marmo 2005, Caimmi 2006a). Additional effort is devoted to the investigation of the properties of axisymmetric and triaxial configurations. A unified theory of systematic and random motions is developed for R3 fluids, taking into consideration imaginary rotation (Caimmi 1996b, 2006a), and a number of theorems previously stated for homeoidally striated Jacobi ellipsoids (Caimmi 2006a) are extended to the more general case of R3 fluids. The effect of random motion excess is shown to be equivalent to an additional real or imaginary rotation, respectively, inducing flattening (along the equatorial plane) or elongation (along the rotation axis). Then it is realized that a R3 fluid always admits an adjoint configuration with isotropic random velocity distribution. In addition, further constraints are established on the amount of random velocity anisotropy along the principal axes, for triaxial configurations. A necessary condition is formulated for the occurrence of bifurcation points from axisymmetric to triaxial configurations in virial equilibrium, which is independent of the anisotropy parameters. A particularization of general relations is made to the special case of homeoidally striated Jacobi ellipsoid, and some previously known results (Caimmi 2006a) are reproduced.

Caimmi, R.

2007-06-01

338

SPRINT: A new parallel framework for R  

PubMed Central

Background Microarray analysis allows the simultaneous measurement of thousands to millions of genes or sequences across tens to thousands of different samples. The analysis of the resulting data tests the limits of existing bioinformatics computing infrastructure. A solution to this issue is to use High Performance Computing (HPC) systems, which contain many processors and more memory than desktop computer systems. Many biostatisticians use R to process the data gleaned from microarray analysis and there is even a dedicated group of packages, Bioconductor, for this purpose. However, to exploit HPC systems, R must be able to utilise the multiple processors available on these systems. There are existing modules that enable R to use multiple processors, but these are either difficult to use for the HPC novice or cannot be used to solve certain classes of problems. A method of exploiting HPC systems, using R, but without recourse to mastering parallel programming paradigms is therefore necessary to analyse genomic data to its fullest. Results We have designed and built a prototype framework that allows the addition of parallelised functions to R to enable the easy exploitation of HPC systems. The Simple Parallel R INTerface (SPRINT) is a wrapper around such parallelised functions. Their use requires very little modification to existing sequential R scripts and no expertise in parallel computing. As an example we created a function that carries out the computation of a pairwise calculated correlation matrix. This performs well with SPRINT. When executed using SPRINT on an HPC resource of eight processors this computation reduces by more than three times the time R takes to complete it on one processor. Conclusion SPRINT allows the biostatistician to concentrate on the research problems rather than the computation, while still allowing exploitation of HPC systems. It is easy to use and with further development will become more useful as more functions are added to the framework.

Hill, Jon; Hambley, Matthew; Forster, Thorsten; Mewissen, Muriel; Sloan, Terence M; Scharinger, Florian; Trew, Arthur; Ghazal, Peter

2008-01-01

339

The Hobbit by J.R.R. Tolkien  

NSDL National Science Digital Library

A collection of resources for use in the study of The Hobbit by J.R.R. Tolkien. Introduction During the past few weeks we will be reading The Hobbit by J.R.R. Tolkien. Before Reading First, you need to be introduced to Hero s Journey. Also called the Monomyth, this is a concept explored by Joseph Campbell. We will talk about it in class, but you can get a nice ...

Cook, Miss

2009-06-25

340

r 17 IW GOGGO!  

Center for Biologics Evaluation and Research (CBER)

Text Version... The leukoredcution processing window -i for one unit of Red Blood Cells is now allowed after 2 hours of refrigeration up to outdate. ... More results from www.fda.gov/downloads/biologicsbloodvaccines/bloodbloodproducts

341

MiR-223 deficiency increases eosinophil progenitor proliferation.  

PubMed

Recently, microRNAs have been shown to be involved in hematopoietic cell development, but their role in eosinophilopoiesis has not yet been described. In this article, we show that miR-223 is upregulated during eosinophil differentiation in an ex vivo bone marrow-derived eosinophil culture system. Targeted ablation of miR-223 leads to an increased proliferation of eosinophil progenitors. We found upregulation of a miR-223 target gene, IGF1R, in the eosinophil progenitor cultures derived from miR-223(-/-) mice compared with miR-223(+/+) littermate controls. The increased proliferation of miR-223(-/-) eosinophil progenitors was reversed by treatment with an IGF1R inhibitor (picropodophyllin). Whole-genome microarray analysis of differentially regulated genes between miR-223(+/+) and miR-223(-/-) eosinophil progenitor cultures identified a specific enrichment in genes that regulate hematologic cell development. Indeed, miR-223(-/-) eosinophil progenitors had a delay in differentiation. Our results demonstrate that microRNAs regulate the development of eosinophils by influencing eosinophil progenitor growth and differentiation and identify a contributory role for miR-223 in this process. PMID:23325891

Lu, Thomas X; Lim, Eun-Jin; Besse, John A; Itskovich, Svetlana; Plassard, Andrew J; Fulkerson, Patricia C; Aronow, Bruce J; Rothenberg, Marc E

2013-01-16

342

Intelligent Biometric System using PCA and R-LDA  

Microsoft Academic Search

The paper presents a novel biometric authentication approach using principal component analysis (PCA), regularized-linear discriminant analysis (R-LDA) and supervised neural networks. Low dimensional feature vectors of human face images are required to drive neural networks effectively. After histogram equalization process each image is presented to PCA or R-LDA for normalization and dimension reduction. The preprocessing steps of PCA or R-LDA

Anupam Shukla; Joydip Dhar; Chandra Prakash; D. Sharma; R. K. Anand; Sourabh Sharma

2009-01-01

343

Revisiting Noether gauge symmetry for F( R) theory of gravity  

NASA Astrophysics Data System (ADS)

Noether gauge symmetry for F( R) theory of gravity has been explored recently. The fallacy is that, even after setting gauge to vanish, the form of F( R)? R n (where n?1 is arbitrary) obtained in the process, has been claimed to be an outcome of gauge Noether symmetry. On the contrary, earlier works proved that any nonlinear form other than F(R) ? R^{3/2} is obscure. Here, we show that, setting gauge term zero, Noether equations are satisfied only for n=2, which again does not satisfy the field equations. Thus, as noticed earlier, the only form that Noether symmetry admits is F(R) ? R^{3/2}. Noether symmetry with non-zero gauge has also been studied explicitly here, to show that it does not produce anything new.

Sk, Nayem; Sanyal, Abhik Kumar

2012-12-01

344

BAM R68: Scintillation Fluid  

Center for Food Safety and Applied Nutrition (CFSAN)

... BAM R68: Scintillation Fluid. January 2001. Bacteriological Analytical Manual. R68 Scintillation Fluid. 2,5 Diphenyloxazole, 5.0 g. ... More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

345

Experimental analysis of a window air conditioner with a R-22 and R32/R125/R134a mixture.  

National Technical Information Service (NTIS)

Much experimental and theoretical analysis of potential R-22 replacements has been accomplished. However, published information about the experimental analysis of any off-the-shelf air conditioner with a potential R-22 replacement at realistic, operating ...

V. C. Mei F. C. Chen D. T. Chen E. P. HuangFu

1995-01-01

346

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

PubMed

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

Prakash, Amresh; Luthra, Pratibha Mehta

2012-01-26

347

Thermodynamic Properties of the Mixtures R23\\/R744 and R41\\/R744 and their Efficiency as Refrigerants  

Microsoft Academic Search

Mixtures of refrigerants are widely used as working substances for refrigerating plants. Among them, mixtures of ozone-safe and natural refrigerants, in particular R23\\/R744 and R41\\/R744, are important. For calculating their thermodynamic properties, we compiled equations of state on the basis of the method in (1). According to this reference, the equation of state for a mixture is presented as a

Aleksandr Vasserman C; Valentine Malchevsky S

348

R-body-producing bacteria.  

PubMed Central

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

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

1989-01-01

349

Measurements of the thermal conductivity of liquid R32, R124, R125, and R141b  

Microsoft Academic Search

This paper reports measurements of the thermal conductivity of refrigerants R32, R124, R125, and R141b in the liquid phase. The measurements, covering a temperature range from 253 to 334 K and pressure up to 20 MPa, have been performed in a transient hotwire instrument employing two anodized tantalum wires. The uncertainty of the present thermal-conductivity data is estimated to be

M. J. Assael; L. Karagiannidis

1995-01-01

350

Ceramic fabrication R D  

SciTech Connect

This project is separated into three tasks. The first task is a design and modeling effort to be carried out by MSE, Inc. The purpose of this task is to develop and analyze designs for various cohesive ceramic fabrication (CCF) components. This quarter, the advanced molybdenum disicilide MHD electrode design was essentially completed. Final refinements will be made after molybdenum disilicide processing results are available and the final layer compositions are established. Work involving whisker incorporation was initiated on the high stress component. It is unlikely that whiskers will become low cost, so particulate reinforcement will be pursued. Modeling work will resume once a suitable aluminum oxide/silicon carbide composition is selected that can be fired to acceptable densities by pressureless sintering. Task 2, subcontracted to Applied Technology Laboratories (ATL), is principally directed at establishing a property data base for monolithic and laminated alumina fabricated using the CCF process. This quarter, ATL demonstrated that the CCF process does not compromise the flexure strength of alumina. Task 3, subcontracted to Ceramics Binder Systems, Inc., focused on CCF silicon carbide particulate reinforced alumina and on the development of processing procedures for nonoxide molybdenum disilicide. Preliminary results indicate that achieving high densities in silicon carbide particulate reinforced aluminum oxide will be difficult. Molybdenum disilicide results are encouraging, and it is clear that the CCF process will work with this nonoxide material. 3 refs., 18 figs., 4 tabs.

Not Available

1990-01-01

351

Unraveling the Regulatory Network in Streptococcus pyogenes: the Global Response Regulator CovR Represses rivR Directly  

Microsoft Academic Search

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

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

2007-01-01

352

NIE Plan to Build Educational R & D Capacity  

ERIC Educational Resources Information Center

Reproduces chapters on the second and third of five proposed programs, which are: (1) internal NIE capability to monitor the R & D System and operating system of education, (2) the R & D system, (3) the linkage and support system, (4) capacity in the operating system and (5) field-initiated research on the processes of educational change.…

Educational Researcher, 1974

1974-01-01

353

R&D and Public Policy-Making.  

ERIC Educational Resources Information Center

Studies on the relationship between research and development (R&D) and public policymaking processes are reviewed. Attention is directed to R&D utilization in Sweden and other countries. The publications are grouped into four categories: policymaking and knowledge utilization, research policy, higher education policy, and knowledge utilization in…

Premfors, Rune; Wittrock, Bjorn

1983-01-01

354

R&D Alert. Volume 7, Number 2, 2005  

ERIC Educational Resources Information Center

|"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…

White, Noel, Ed.

2005-01-01

355

Possible Problems in ENDF/B-VI.r8.  

National Technical Information Service (NTIS)

The 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 document proposes an alternative to the curr...

D. Brown G. Hedstrom

2003-01-01

356

Fragmentation Processes  

NASA Astrophysics Data System (ADS)

Preface; 1. Direct and resonant double-photoionization: from atoms to solids L. Avaldi and G. Stefani; 2. The application of propagation exterior complex scaling to atomic collisions P. L. Bartlett and A. T. Stelbovics; 3. Fragmentation of molecular-ion beams in intense ultra-short laser pulses I. Ben-Itzhak; 4. Atoms with one and two active electrons in strong laser fields I. A. Ivanov and A. S. Kheifets; 5. Experimental aspects of ionization studies by positron and positronium impact G. Laricchia, D. A. Cooke, Á. Kövér and S. J. Brawley; 6. (e,2e) spectroscopy using fragmentation processes J. Lower, M. Yamazaki and M. Takahashi; 7. A coupled pseudostate approach to the calculation of ion-atom fragmentation processes M. McGovern, H. R. J. Walters and C. T. Whelan; 8. Electron Impact Ionization using (e,2e) coincidence techniques from threshold to intermediate energies A. J. Murray; 9. (e,2e) processes on atomic inner shells C. T. Whelan; 10. Spin resolved atomic (e,2e) processes J. Lower and C. T. Whelan; Index.

Whelan, Colm T.

2012-12-01

357

Silicon Production Process Evaluations.  

National Technical Information Service (NTIS)

The chemical engineering analysis of the preliminary process design of a process for producing solar cell grade silicon from dichlorosilane is presented. A plant to produce 1,000 MT/yr of silicon is analyzed. Progress and status for the plant design are r...

1981-01-01

358

Comparative energy and exergy analysis of R744, R404A and R290 refrigeration cycles  

Microsoft Academic Search

A detailed energy and exergy analysis of the low global warming potential refrigerants R744 and R290 was preformed and compared against the commercial refrigerant R404A in a single-stage vapour compression cycle and R744 in a two-stage vapour compression cycle with an internal heat exchanger. Copyright The Author 2009. Published by Oxford University Press. All rights reserved. For Permissions, please email:

J. A. Shilliday; S. A. Tassou; N. Shilliday

2009-01-01

359

Multi-way R-tree joins using indirect predicates  

Microsoft Academic Search

Since spatial join processing consumes much time, several algorithms have been proposed to improve spatial join performance. Spatial join has been processed in two steps, called filter step and refinement step. The M-way R-tree join (MRJ) is a filter step join algorithm, which synchronously traverses M R-trees. In this paper, we introduce indirect predicates which do not directly come from

Ho-Hyun Park; Jun-Ki Min; Chin-Wan Chung; Tae-Gyu Chang

360

Transport properties of refrigerants R32, R125, R134a, and R125+R32 mixtures in and beyond the critical region  

Microsoft Academic Search

A practical representation for the transport coefficients of pure refrigerants R32, R125, R134a, and R125+R32 mixtures is presented which is valid in the vapor–liquid critical region. The crossover expressions for the transport coefficients incorporate scaling laws near the critical point and are transformed to regular background values far away from the critical point. The regular background parts of the transport

S. B Kiselev; R. A Perkins; M. L Huber

1999-01-01

361

Staubbildung in den Huellen von Kohlenstoffsternen: R Coronae Borealis (Dust Production in the Envelopes of Carbon Stars: R Coronae Borealis).  

National Technical Information Service (NTIS)

A quantitative, analytic model of darkening events of R Coronae Borealis, based on phenomenological models of light decline by soot formation, with focus on causal relation between the pulsating atmosphere and episodic condensation processes, is presented...

A. Goeres

1992-01-01

362

Genes-R-Us  

NSDL National Science Digital Library

Genetics and genetic counseling--- How can the modern student relate to the classic principles of genetics? How about forming a genetic counseling agency with your students and "serve" the entire senior class during their "marriage project" in senior health? Genetic counseling can introduce students to basic genetics, an important interface of the biological sciences and the human condition. Many high schools throughout the U.S. have "marriage" or family living programs in which students are randomly paired early in the school year. They work to plan a wedding, a household budget that includes rent, car bills, food bills, and so on, including a future family. It is this future family that attracted my attention a few years back. The students were randomly given a baby to care for (the baby was either an uncooked egg, or a five pound sack of flour.) This is a perfect time to introduce human genetics to the soon-to-be parents. Hence, GENES-R-US !

Richard Benz (Wickliffe High School REV)

1994-07-30

363

Chromatin Structure and Transcription of the R1- and R2Inserted rRNA Genes of Drosophila melanogaster  

Microsoft Academic Search

About half of the rRNA gene units (rDNA units) of Drosophila melanogaster are inserted by the retrotrans- posable elements R1 and R2. Because transcripts to R1 and R2 were difficult to detect on blots and electron microscopic observations of rRNA synthesis suggested that only uninserted rDNA units were transcribed, it has long been postulated that inserted rDNA units are in

Junqiang Ye; Thomas H. Eickbush

2006-01-01

364

Large Deviations for the Fermion Point Process Associated with the Exponential Kernel  

NASA Astrophysics Data System (ADS)

For the fermion point process on the whole complex plane associated with the exponential kernel e^{zbar{w}}, we show the central limit theorem for the random variable ?( D r , the number of points inside the ball D r of radius r, as r ? ? and we establish the large deviation principle for the random variables { r -2? ( D r ), r > 0}.

Shirai, Tomoyuki

2006-05-01

365

Spatial Joins Using R-trees: Breadth-First Traversal with Global Optimizations  

Microsoft Academic Search

R-tree based spatial join is useful because of both its superior performance and the wide spread implementation of R-trees. We present a new R-tree join method called BFRJ (Breadth-First R-tree Join). BFRJ syn- chronously traverses both R-trees in breadth- first order while processing join computation one level at a time. At each level, BFRJ creates an intermediate join index and

Yun-wu Huang; Ning Jing; Elke A. Rundensteiner

1997-01-01

366

Assessment of Advanced Coal-Gasification Processes.  

National Technical Information Service (NTIS)

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 Proces...

J. Ferrall J. Houseman J. McCarthy T. Charng

1981-01-01

367

R-Parity-violating supersymmetry  

Microsoft Academic Search

Theoretical and phenomenological implications of R-parity violation in supersymmetric theories are discussed in the context of particle physics and cosmology. Fundamental aspects include the relation with continuous and discrete symmetries and the various allowed patterns of R-parity breaking. Recent developments on the generation of neutrino masses and mixings within different scenarios of R-parity violation are discussed. The possible contribution of

R. Barbier; C. Bérat; M. Besançon; M. Chemtob; A. Deandrea; E. Dudas; P. Fayet; S. Lavignac; G. Moreau; E. Perez; Y. Sirois

2005-01-01

368

Experimental analysis of a window air conditioner with a R-22 and R32\\/R125\\/R134a mixture  

Microsoft Academic Search

Much experimental and theoretical analysis of potential R-22 replacements has been accomplished. However, published information about the experimental analysis of any off-the-shelf air conditioner with a potential R-22 replacement at realistic, operating conditions is still rare. This type of work could be useful because it provides baseline data for comparing the performance of R-22 and its potential replacement at drop-in

V. C. Mei; F. C. Chen; D. T. Chen; E. P. HuangFu

1995-01-01

369

Evolution of rDNA in Nicotiana Allopolyploids: A Potential Link between rDNA Homogenization and Epigenetics  

PubMed Central

Background The evolution and biology of rDNA have interested biologists for many years, in part, because of two intriguing processes: (1) nucleolar dominance and (2) sequence homogenization. We review patterns of evolution in rDNA in the angiosperm genus Nicotiana to determine consequences of allopolyploidy on these processes. Scope Allopolyploid species of Nicotiana are ideal for studying rDNA evolution because phylogenetic reconstruction of DNA sequences has revealed patterns of species divergence and their parents. From these studies we also know that polyploids formed over widely different timeframes (thousands to millions of years), enabling comparative and temporal studies of rDNA structure, activity and chromosomal distribution. In addition studies on synthetic polyploids enable the consequences of de novo polyploidy on rDNA activity to be determined. Conclusions We propose that rDNA epigenetic expression patterns established even in F1 hybrids have a material influence on the likely patterns of divergence of rDNA. It is the active rDNA units that are vulnerable to homogenization, which probably acts to reduce mutational load across the active array. Those rDNA units that are epigenetically silenced may be less vulnerable to sequence homogenization. Selection cannot act on these silenced genes, and they are likely to accumulate mutations and eventually be eliminated from the genome. It is likely that whole silenced arrays will be deleted in polyploids of 1 million years of age and older.

Kovarik, Ales; Dadejova, Martina; Lim, Yoong K.; Chase, Mark W.; Clarkson, James J.; Knapp, Sandra; Leitch, Andrew R.

2008-01-01

370

R & D funding in 1981  

NASA Astrophysics Data System (ADS)

Although it is widely accepted that federal budgets will be cut during the next year, it is apparent now that R & D support will remain strong for FY 1981. The National Science Foundation's overall budget has been increased by 8% for FY 1981. NASA R & D has gained 7% on its budget. The Department of Commerce R & D budget has been increased by 6%. The huge increases are among the military and defense agencies, some amounting to as much as 37% (Air Force), with an average DOD R & D increase of 19%. The table lists the increases by agency.

Bell, Peter M.

371

Experimental analysis of a window air conditioner with a R-22 and R32/R125/R134a mixture  

SciTech Connect

Much experimental and theoretical analysis of potential R-22 replacements has been accomplished. However, published information about the experimental analysis of any off-the-shelf air conditioner with a potential R-22 replacement at realistic, operating conditions is still rare. This type of work could be useful because it provides baseline data for comparing the performance of R-22 and its potential replacement at drop-in conditions. In this study, an off-the-shelf window air conditioner was tested at Air Conditioning and Refrigeration Institute (ARI)-rated indoor conditions and at different ambient temperatures, including the ARI-rated outdoor condition, with R-22 and with its potential replacement, a ternary mixture of R-32(30%)/R-125(10%)/R-134a(60%) (the ternary mixture). A test rig was built that provided for baseline operation and for the option of operating the system with a flooded evaporator by means of liquid over-feeding (LOF). The test results indicated the cooling capacity of the ternary mixture was 7.7% less than that of R-22 at 95{degrees}F ambient for baseline operation. The cooling capacity for both refrigerants improved when a flooded evaporator, or LOF, was used. For LOF operation, the cooling capacity of the ternary mixture was only 1.1% less than that of R-22. The ternary mixture had slightly higher compressor discharge pressure, a lower compressor discharge temperature, slightly lower compressor power consumption, and a higher compressor high/low pressure ratio.

Mei, V.C.; Chen, F.C.; Chen, D.T. [Oak Ridge National Lab., TN (United States); HuangFu, E.P. [USDOE, Washington, DC (United States)

1995-07-01

372

Measurements of the thermal conductivity of liquid R32, R124, R125, and R141b  

NASA Astrophysics Data System (ADS)

This paper reports measurements of the thermal conductivity of refrigerants R32, R124, R125, and R141b in the liquid phase. The measurements, covering a temperature range from 253 to 334 K and pressure up to 20 MPa, have been performed in a transient hotwire instrument employing two anodized tantalum wires. The uncertainty of the present thermal-conductivity data is estimated to be ±0.5%. The experimental data have been represented by polynomial functions of temperature and pressure for the purposes of interpolation. A comparison with other recent measurements is also included.

Assael, M. J.; Karagiannidis, L.

1995-07-01

373

catR: An R Package for Computerized Adaptive Testing  

Microsoft Academic Search

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 testing platform to the interested user. Several item-selection rules

David Magis; Gilles Raîche

2011-01-01

374

"catR": An R Package for Computerized Adaptive Testing  

ERIC Educational Resources Information Center

|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…

Magis, David; Raiche, Gilles

2011-01-01

375

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

SciTech Connect

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.

PADULA,S.

2002-07-18

376

The viscosity of R32 and R125 at saturation  

Microsoft Academic Search

This paper reports new measurements of the viscosity of R32 and R125, in both the liquid and the vapor phase, over the temperature range 220 to 343 K near the saturation line. The measurements in both liquid and vapor phases have been carried out with a vibrating-wire viscometer calibrated with respect to standard reference values of viscosity. It is estimated

C. M. B. P. Oliveira; W. A. Wakeham

1993-01-01

377

Determination of (R,R)-glycopyrronium bromide and its related impurities by ion-pair HPLC.  

PubMed

A simple, rapid and specific ion-pair HPLC method for the determination of (R,R)-glycopyrronium bromide and its related impurities is presented, and parameters affecting the chromatographic properties of these compounds are discussed. Optimal analyte separation was achieved on base deactivated Nucleosil at 40 degrees C, using phosphate buffer pH 2.30 with sodium-1-decanesulfonate (0.01 M)/methanol (35/65; v/v) as eluent for isocratic elution at a flow rate 1 ml x min(-1). The analytical assay was validated according to international guidelines. The methodis suitable for in-process control and as stability indicating assay. PMID:17663184

Nebiu, D; Walter, M; Lachmann, B; Kopelent, H; Noe, C R

2007-06-01

378

Ceramic fabrication R D  

SciTech Connect

This project is separated into three tasks. The first task is a design and modeling effort to be carried out by MSE, Inc. The purpose of this task is to develop and analyze designs for various cohesive ceramic fabrication (CCF) components, including an MHD electrode for strategic defense initiative (SDI) applications and a high stress, low cost, reinforced ceramic component for armor applications. The MHD electrode design is substantially completed. A layered structure composed of molybdenum disilicide graded with quartz glass has been designed and analyzed using finite element methods. The design demonstrates the fabrication capabilities of the CCF process. The high stress, armor application component will be silicon carbide reinforced alumina in thick plates. 2 refs., 4 figs., 1 tab.

Not Available

1990-01-01

379

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...

380

Parallel Processing of Spatial Joins Using R-trees  

Microsoft Academic Search

In this paper, we show that spatial joins are very suitable to be proc- essed on a parallel hardware platform. The parallel system is equipped with a so-called shared virtual memory which is well- suited for the design and implementation of parallel spatial join al- gorithms. We start with an algorithm that consists of three phases: task creation, task assignment

Thomas Brinkhoff; Hans-peter Kriegel; Bernhard Seeger

1996-01-01

381

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...

382

HuR/Methyl-HuR and AUF1 regulate the MAT expressed during liver proliferation, differentiation and carcinogenesis  

PubMed Central

Background & Aims Hepatic de-differentiation, liver development, and malignant transformation are processes in which the levels of hepatic S-adenosylmethionine (SAMe) are tightly regulated by two genes, MAT1A and MAT2A. MAT1A is expressed in the adult liver, whereas MAT2A expression is primarily extra-hepatic and is strongly associated with liver proliferation. The mechanisms that regulate these expression patterns are not completely understood. In silico analysis of the 3? untranslated region of MAT1A and MAT2A revealed putative binding sites for the RNA-binding proteins AUF1 and HuR, respectively. We investigated the post-transcriptional regulation of MAT1A and MAT2A by AUF1, HuR and methyl-HuR in the aforementioned biological processes. Results During hepatic de-differentiation, the switch between MAT1A and MAT2A coincided with an increase in HuR and AUF1 expression. SAMe treatment altered this homeostasis by shifting the balance of AUF1 and methyl-HuR/HuR, which was identified for the first time as an inhibitor of MAT2A mRNA stability. We also observed a similar temporal distribution and a functional link between HuR, methyl-HuR, AUF1, and MAT1A and MAT2A during the fetal liver development. Immunofluorescent analysis revealed increased levels of HuR and AUF1, and a decrease in methyl-HuR levels in human livers with hepatocellular carcinoma (HCC). Conclusions Our data strongly support a role for AUF1 and HuR/methyl-HuR in liver de-differentiation, development and human HCC progression through the post-translational regulation of MAT1A and MAT2A mRNAs.

Vazquez-Chantada, Mercedes; Fernandez-Ramos, David; Embade, Nieves; Martinez-Lopez, Nuria; Varela-Rey, Marta; Woodhoo, Ashwin; Luka, Zigmund; Wagner, Conrad; Anglim, Paul P.; Finnell, Richard H.; Caballeria, Juan; Laird-Offringa, Ite A.; Gorospe, Myriam; Lu, Shelly C; Mato, Jose M; Martinez-Chantar, M Luz

2010-01-01

383

INFLUENCE OF IRON CHELATION ON R1 AND R2 CALIBRATION CURVES IN GERBIL LIVER AND HEART  

PubMed Central

MRI is gaining increasing importance for the noninvasive quantification of organ iron burden. Since transverse relaxation rates depend on iron distribution as well as iron concentration, physiologic and pharmacologic processes that alter iron distribution could change MRI calibration curves. This paper compares the effect of three iron chelators, deferoxamine, deferiprone, and deferasirox on R1 and R2 calibration curves according to two iron loading and chelation strategies. 33 Mongolian gerbils underwent iron loading (iron dextran 500 mg/kg/wk) for 3 weeks followed by 4 weeks of chelation. An additional 56 animals received less aggressive loading (200 mg/kg/week) for 10 weeks, followed by 12 weeks of chelation. R1 and R2 calibration curves were compared to results from 23 iron-loaded animals that had not received chelation. Acute iron loading and chelation biased R1 and R2 from the unchelated reference calibration curves but chelator-specific changes were not observed, suggesting physiologic rather than pharmacologic differences in iron distribution. Long term chelation deferiprone treatment increased liver R1 50% (p<0.01), while long term deferasirox lowered liver R2 30.9% (p<0.0001). The relationship between R1 and R2 and organ iron concentration may depend upon the acuity of iron loading and unloading as well as the iron chelator administered.

Wood, John C.; Aguilar, Michelle; Otto-Duessel, Maya; Nick, Hanspeter; Nelson, Marvin D.; Moats, Rex

2008-01-01

384

The Thermal Diffusivity of the Refrigerants R32, R125, and R143a  

Microsoft Academic Search

The thermal diffusivity of the halogenated fluorocarbons R32, R125, and R143a was systematically measured in a wide region of state around the liquid-vapor critical point using dynamic light scattering as the measuring method. The experimental setup is capable of measuring in homodyne (high light intensity) or heterodyne mode (low light intensity). Especially in the vicinity of the critical point, this

M. Pitschmann; J. Straub

2002-01-01

385

Retrotransposable Elements R1 and R2 Interrupt the rRNA Genes of Most Insects  

Microsoft Academic Search

A large number of insect species have been screened for the presence of the retrotransposable elements R1 and R2. These elements integrate independently at specific sites in the 28S rRNA genes. Genomic blots indicated that 43 of 47 insect species from nine orders contained insertions, ranging in frequency from a few percent to >50% of the 28S genes. Sequence analysis

John L. Jakubczak; William D. Burke; Thomas H. Eickbush

1991-01-01

386

R.R.R. Dhlomo and the early black South African short story in English  

Microsoft Academic Search

The continuing fascination with Drum, Sophiatown and the writers of the 1950s has often overshadowed the achievements of an earlier generation of black writers. This article looks at R.R.R. Dhlomo, an early exponent of the short story in English, and explores his ambivalent position as a member of the mission?educated African elite of the 1930s and 1940s. As a ‘new

Rob Gaylard

2005-01-01

387

Thermal conductivity of refrigerants R123, R134a, and R125 at low temperatures  

Microsoft Academic Search

Using a transient coaxial cylinder technique, thermal conductivities were measured for liquid 1,1,1-trifluoro-2,2-dichloroethane (refrigerant R123), 1,1,1,2-tetrafluoroethane (refrigerant R134a). and pentalluoroethane (refrigerant R 125). The uncertainty of the experimental data is estimated to be within 2–3 %. Thermal conductivities of refrigerants were measured at temperatures ranging from -114 to 20°C under pressures up to IOMPa. The apparatus was calibrated with four

O. B. Tsvetkov; Yu. A. Laptev; A. G. Asambaev

1994-01-01

388

Thermal conductivity of refrigerants R123, R134a, and R125 at low temperatures  

Microsoft Academic Search

Using a transient coaxial cylinder technique, thermal conductivities were measured for liquid 1,1,1-trifluoro-2,2-dichloroethane (refrigerant R123), 1,1,1,2-tetrafluoroethane (refrigerant R134a). and pentalluoroethane (refrigerant R 125). The uncertainty of the experimental data is estimated to be within 2 3 %. Thermal conductivities of refrigerants were measured at temperatures ranging from -114 to 20°C under pressures up to IOMPa. The apparatus was calibrated with

O. B. Tsvetkov; Yu. A. Laptev; A. G. Asambaev

1994-01-01

389

Competition between R1 and R2 transposable elements in the 28S rRNA genes of insects  

Microsoft Academic Search

R1 and R2 are non-LTR retrotransposons that insert in the 28S rRNA genes of arthropods. R1 elements insert into a site that is 74 bp downstream of the R2 insertion site, thus the presence of an R2 in the same 28S gene may inhibit the expression of R1. Consistent with such a suggestion, the R1 elements of Drosophila melanogaster have

J. Ye; C. E. Pérez-González; D. G. Eickbush; T. H. Eickbush

2005-01-01

390

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 SABREâ?¢ Process), is a technology designed to destroy nitroaromatic and energetic compounds. The process does not evolve any known toxic intermedi...

391

miR-221 overexpression contributes to liver tumorigenesis.  

PubMed

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

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

2009-12-15

392

miR-221 overexpression contributes to liver tumorigenesis  

PubMed Central

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.

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

2009-01-01

393

Chemical Informatics Functionality in R  

Microsoft Academic Search

The flexibility and scope of the R programming environment has made it a popular choice for statistical modeling and scientific prototyping in a number of fields. In the field of chemistry, R provides several tools for a variety of problems related to statistical modeling of chemical information. However, one aspect common to these tools is that they do not have

Rajarshi Guha

2007-01-01

394

Military R&D Communities.  

ERIC Educational Resources Information Center

Military research and development (R&D) in Western countries and the USSR are analyzed in terms of growth; self-perception of R&D personnel; relationships with industry and the state bureaucracy; reproduction schemes which result in war-oriented work; and worker training. Prospects are slim for the conversion of military production to civilian…

Albrecht, Ulrich

1983-01-01

395

Loss of RNase R Induces Competence Development in Legionella pneumophila? †  

PubMed Central

RNase R is a processive 3?-5? exoribonuclease with a high degree of conservation in prokaryotes. Although some bacteria possess additional hydrolytic 3?-5? exoribonucleases such as RNase II, RNase R was found to be the only predicted one in the facultative intracellular pathogen Legionella pneumophila. This provided a unique opportunity to study the role of RNase R in the absence of an additional RNase with similar enzymatic activity. We investigated the role of RNase R in the biology of Legionella pneumophila under various conditions and performed gene expression profiling using microarrays. At optimal growth temperature, the loss of RNase R had no major consequence on bacterial growth and had a moderate impact on normal gene regulation. However, at a lower temperature, the loss of RNase R had a significant impact on bacterial growth and resulted in the accumulation of structured RNA degradation products. Concurrently, gene regulation was affected and specifically resulted in an increased expression of the competence regulon. Loss of the exoribonuclease activity of RNase R was sufficient to induce competence development, a genetically programmed process normally triggered as a response to environmental stimuli. The temperature-dependent expression of competence genes in the rnr mutant was found to be independent of previously identified competence regulators in Legionella pneumophila. We suggest that a physiological role of RNase R is to eliminate structured RNA molecules that are stabilized by low temperature, which in turn may affect regulatory networks, compromising adaptation to cold and thus resulting in decreased viability.

Charpentier, Xavier; Faucher, Sebastien P.; Kalachikov, Sergey; Shuman, Howard A.

2008-01-01

396

High Efficiency R-744 Commercial Heat Pump Water Heaters.  

National Technical Information Service (NTIS)

The project investigated the development and improvement process of a R744 (CO2) commercial heat pump water heater (HPWH) package of approximately 35 kW. The improvement process covered all main components of the system. More specific the heat exchangers ...

S. Elbel

2013-01-01

397

R-parity violation at HERA  

NASA Astrophysics Data System (ADS)

We summarize the signals at HERA in supersymmetric models with explicitly broken R-parity. As the most promising case, we consider in detail the resonant production of single squarks through an operator L1QiDj, a production process analogous to that for leptoquarks. However, the dominant decay of the squark to a quark and a photino leads to a very different experimental signature. We examine in particular the case where the photino decays to a positron and two quarks. Using a detailed Monte Carlo procedure we obtain a discovery limit in the squark mass-Yukawa coupling plane. HERA can discover a squark for a mass as large as 270 GeV and for an R-parity violating Yukawa coupling as small as 5.8 × 10-3.

Butterworth, J.; Dreiner, H.

1993-05-01

398

Mechanisms for chemical transformations of (R,R)-tartaric acid on Cu(110): A first principles study  

NASA Astrophysics Data System (ADS)

Periodic density functional theory calculations are used to systematically investigate, for the first time, the mechanisms for chemical transformations of (R,R)-tartaric acid on a model Cu(110) surface. The overall potential energy surface for the chemical transformations is revealed. The calculations show that the adsorption of the intact biacid molecules of (R,R)-tartaric acid on Cu(110) surface is not strong, but upon adsorption on Cu(110), the biacid molecules will chemically transform immediately, rather than desorb from the surface. It is found that the chemical transformations of (R,R)-tartaric acid on Cu(110) is a thermodynamically favorable process, to produce the monotartrate species, bitartrate species, and H atoms. Kinetically, the initial reaction step is only one O-H bond scission in either one of the COOH group of a biacid molecule of (R,R)-tartaric acid leading to the formation of a monotartrate species and a H atom, which is an almost spontaneous process. The rate-controlling step is the O-H bond scission in the COOH group of a monotartrate species producing a bitartrate species and a H atom. The concerted reaction for simultaneously breaking the two O-H bonds in both COOH groups of a biacid molecule cannot proceed.

Zhang, Ji; Lu, Tao; Jiang, Chen; Zou, Jianwei; Cao, Fengqi; Chen, Yadong

2009-10-01

399

miR-3928 activates ATR pathway by targeting Dicer  

PubMed Central

Alterations in microRNA (miRNA) expression have been observed in cells subjected to exogenous stresses, implying that miRNAs play an important role in cellular stress response; however, the underlying mechanism is still largely unknown. In the present study, we found that miR-3928 was implicated in cellular response to ionizing radiation. After exposed to X-rays, miR-3928 expression increased in 1.5 h and then decreased, meanwhile Dicer, a key component in the miRNA processing machinery, increased gradually. An oscillation was observed in the expression of both mature miR-3928 and Dicer mRNA from 2 h to 3.5 h in irradiated cells. Then, we verified that miR-3928 directly bound to the 3'-untranslated region of Dicer mRNA. Consequently, Dicer expression was suppressed and the maturation of other miRNAs including miR-185, miR-300, and miR-663, was inhibited. Overexpression of miR-3928 induced DNA damage, activated ATR, and phosphorylated Chk1 accompanied by G1 arrest. Taken together, these findings replenished ATR/Chk1 pathway by revealing a novel miRNA regulatory network in response to exogenous stress, in which miR-3928 plays an important role in regulating the expression of Dicer.

Chang, Lei; Hu, Wentao; Ye, Caiyong; Yao, Bin; Song, Lei; Wu, Xin; Ding, Nan; Wang, Jufang; Zhou, Guangming

2012-01-01

400

Thermal conductivity of refrigerants R123, R134a, and R125 at low temperatures  

NASA Astrophysics Data System (ADS)

Using a transient coaxial cylinder technique, thermal conductivities were measured for liquid 1,1,1-trifluoro-2,2-dichloroethane (refrigerant R123), 1,1,1,2-tetrafluoroethane (refrigerant R134a). and pentalluoroethane (refrigerant R 125). The uncertainty of the experimental data is estimated to be within 2 3 %. Thermal conductivities of refrigerants were measured at temperatures ranging from -114 to 20°C under pressures up to IOMPa. The apparatus was calibrated with four kinds of liquids and gases. The features of the density dependence of thermal conductivity are indicated. Existing equations for calculating the coefficient are analyzed in cases where development has been sufficient to enable comparisons to be made with experiment. Saturated-liquid thermal conductivities for R134a and R123 are compared with corresponding experimental values.

Tsvetkov, O. B.; Laptev, Yu. A.; Asambaev, A. G.

1994-03-01

401

The viscosity of R32 and R125 at saturation  

Microsoft Academic Search

This paper reports new measurements of the viscosity of R32 and R125, in both the liquid and the vapor phase, over the temperature\\u000a range 220 to 343 K near the saturation line. The measurements in both liquid and vapor phases have been carried out with a\\u000a vibrating-wire viscometer calibrated with respect to standard reference values of viscosity. It is estimated

C. M. B. P. Oliveira; W. A. Wakeham

1993-01-01

402

The Relationship between the WJ-R Gf-Gc Cognitive Clusters and Mathematics Achievement across the Life-Span  

Microsoft Academic Search

The relationship between the Woodcock-Johnson Psycho-Educational Battery-Revised (WJ-R) cognitive clusters (Long-Term Retrieval, Short-Term Memory, Visual Processing, Auditory Processing, Processing Speed, Comprehension-Knowledge, Fluid Reasoning) and mathematics achievement measures (WJ-R Basic Mathematics Skills and Mathematics Reasoning clusters) was investigated in the WJ-R standardization sample. Multiple regression analysis with the WJ-R cognitive clusters as predictors and the mathematics achievement measures as criteria at

Kevin S. McGrew; Gary L. Hessler

1995-01-01

403

PaR-PaR laboratory automation platform.  

PubMed

Labor-intensive multistep biological tasks, such as the construction and cloning of DNA molecules, are prime candidates for laboratory automation. Flexible and biology-friendly operation of robotic equipment is key to its successful integration in biological laboratories, and the efforts required to operate a robot must be much smaller than the alternative manual lab work. To achieve these goals, a simple high-level biology-friendly robot programming language is needed. We have developed and experimentally validated such a language: Programming a Robot (PaR-PaR). The syntax and compiler for the language are based on computer science principles and a deep understanding of biological workflows. PaR-PaR allows researchers to use liquid-handling robots effectively, enabling experiments that would not have been considered previously. After minimal training, a biologist can independently write complicated protocols for a robot within an hour. Adoption of PaR-PaR as a standard cross-platform language would enable hand-written or software-generated robotic protocols to be shared across laboratories. PMID:23654257

Linshiz, Gregory; Stawski, Nina; Poust, Sean; Bi, Changhao; Keasling, Jay D; Hillson, Nathan J

2012-10-09

404

Rolling Deck to Repository (R2R): Research Cruise Event Logger  

NASA Astrophysics Data System (ADS)

Scientific event logs, used by the science party to record scientific sampling events that occur during a research cruise, have been used in various ways for decades. An event log is very important for documenting the occurrence of a sampling event and its location, time, relative sequence, and related details. Event logging, done well, can provide important documentation about scientific data collected during a cruise, and enable more efficient use of those data by cruise participants and future researchers. When the resultant event log is a digital data file, with content generated programmatically and controlled by term vocabularies, it becomes an even more valuable addition to the full complement of data sets generated during the cruise. However, such a tool is only effective if it is used. Through field testing, several key factors were identified that encourage the use of such a tool: the ability to customize the tool to represent the science implementation plan, proposed sampling scheme, cruise personnel and instrumentation; the ability to retrieve date, time and location data automatically from the shipboard network and the ability to enter events quickly and from any location on the ship. This presentation provides an overview of both the current version 1 and soon to be released version 2 of the Rolling Deck to Repository (R2R) research cruise Event Logger system. The R2R Event Logger application is built upon a pre-existing, open-source, weblog product called ELOG (ELOG URL: http://midas.psi.ch/elog/). We provide an oceanographer's view of the full process by which: 1) the R2R Event Logger application is configured and tested to meet the unique needs of a research cruise; 2) the R2R project works with the ship operator to install the Event Logger on the ship designated for the cruise, 3) the Event Logger is configured to automatically retrieve location, time, and other pertinent information from the shipboard network; 4) a copy of the event log file is made available to the science party at the end of the cruise and incorporated into the official shipboard data distribution; and 5) such event logs can be incorporated, accessed, and reviewed as part of scientific data holdings found in repositories such as the NSF funded Biological and Chemical Oceanography Data Management Office (BCO-DMO). A demonstration instance of the R2R Event Logger application, including a Web-based system for generating the custom configuration files (part of version 2 development), will be made available for researcher examination, evaluation and feedback.

Chandler, C. L.; Maffei, A. R.; Stolp, L.; Dubois, D. L.

2011-12-01

405

Energetic (keV) Ionosphere-Origin Ions Found Between R= 2 and 23 R E  

NASA Astrophysics Data System (ADS)

With the flight of ion composition instruments on the Polar satellite, beginning some eight years ago, adding to several earlier missions of varied orbits, we now have essentially contiguous altitude records of the outflow of energized ionospheric ions from R= 2 R E (geocentric) to R= 23 R E, at least in the energy range from a few tens of eV/e to a few tens of keV/e. Magnetotail ion composition measurements in that energy range were first made more than 20 years ago during the ISEE mission (within 23 R E) and are again being made with the Cluster satellites (within 20 R E). According to the several years of ISEE measurements, the nearly omnipresent, singly charged oxygen ions, in particular, have a broad energy distribution within the tail plasma sheet, typically averaging about 3-5 keV. This may be contrasted with mean O+ energies of only 0.2-0.4 keV observed in the ion outflow at R ˜ 2 R E by the Polar TIMAS instrument. The same instrument finds the O+ mean energy to have increased to 1 keV or more by the time the ions have reached R ˜ 4-9 R E, while the total rate of O+ outflow (ions per second) above the nominal 15 eV minimum energy (plus spacecraft potential) has increased about fivefold. An important part of this progressive energization is transverse acceleration across the geomagnetic field lines. As will be shown, this process is sometimes resolved within the O+ gyro period by the TIMAS instrument at these high altitudes. Early TIMAS results suggest that this kind of acceleration is intermittent and explosive and arguably caused by magnetic field-aligned space charge structures associated with earthward bursts of hot and filamentary magnetospheric plasma. The TIMAS data also imply that ionospheric ions are directly injected into the ring current region, but the very energetic O+ (~100 keV) that is known to be a large component of the storm-time ring current has most likely arrived from the plasma sheet, undergoing adiabatic betatron and Fermi acceleration.

Lennartsson, O. W.

2004-05-01

406

Decreased expression of miR-21, miR-26a, miR-29a, and miR-142-3p in CD4? T cells and peripheral blood from tuberculosis patients.  

PubMed

The vast majority of Mycobacterium tuberculosis (M. tuberculosis) infected individuals are protected from developing tuberculosis and T cells are centrally involved in this process. MicroRNAs (miRNA) regulate T-cell functions and are biomarker candidates of disease susceptibility and treatment efficacy in M. tuberculosis infection. We determined the expression profile of 29 selected miRNAs in CD4(+) T cells from tuberculosis patients and contacts with latent M. tuberculosis infection (LTBI). These analyses showed lower expression of miR-21, miR-26a, miR-29a, and miR-142-3p in CD4(+) T cells from tuberculosis patients. Whole blood miRNA candidate analyses verified decreased expression of miR-26a, miR-29a, and miR-142-3p in children with tuberculosis as compared to healthy children with LTBI. Despite marked variances between individual donor samples, trends of increased miRNA candidate expression during treatment and recovery were observed. Functional in vitro analysis identified increased miR-21 and decreased miR-26a expression after re-stimulation of T cells. In vitro polarized Interleukin-17 positive T-cell clones showed activation-dependent miR-29a up-regulation. In order to characterize the role of miR-29a (a described suppressor of Interferon-? in tuberculosis), we analyzed M. tuberculosis specific Interferon-? expressing T cells in children with tuberculosis and healthy contacts but detected no correlation between miR-29a and Interferon-? expression. Suppression of miR-29a in primary human T cells by antagomirs indicated no effect on Interferon-? expression after in vitro activation. Finally, classification of miRNA targets revealed only a moderate overlap between the candidates. This may reflect differential roles of miR-21, miR-26a, miR-29a, and miR-142-3p in T-cell immunity against M. tuberculosis infection and disease. PMID:23613882

Kleinsteuber, Katja; Heesch, Kerrin; Schattling, Stefanie; Kohns, Malte; Sander-Jülch, Claudia; Walzl, Gerhard; Hesseling, Anneke; Mayatepek, Ertan; Fleischer, Bernhard; Marx, Florian M; Jacobsen, Marc

2013-04-16

407

Vapour-liquid equilibrium of ternary mixtures of the refrigerants R125, R143a and R134a  

Microsoft Academic Search

Apart from ternary mixtures of R32 with R125 and R134a, similar mixtures with R143a instead of R32 are discussed as alternatives to the widely used refrigerants R22 and R502. In the present work, the phase equilibrium of such ternary mixtures is described by simple cubic equations of state which are based only on experimental data for the pure substances and

M Nagel; K Bier

1996-01-01

408

Issues on Selecting National R&D Project  

NASA Astrophysics Data System (ADS)

Because of the difficulties on selecting National R&D projects, it is expected that the errors of decision making can be reduced if the information on project (i.e. project duration, people, budget etc.), and its evaluation result is properly provided to stakeholders as a reference. In reality, however, the result of project evaluation is rarely utilized in its own purpose. One reason is that the information on evaluation result and budget is not shared amongst stakeholders at the right time. The other is that the interconnection between systems to support the R&D evaluation and budget information is not realized yet for further utilization. Therefore, this paper is focused on the improvement of decision process that reviews and selects the R&D project to provide relevant information through the data mapping approaches from different system domain and to suggest the enhanced process for the seamless interconnection between National R&D performance evaluation and budget information.

Lee, Joon; Kook, Youn-Gyou; Kim, Jae-Soo; Choi, Ki-Seock

409
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