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1

Neutron Captures in the r-Process  

E-print Network

The r-process involves neutron-rich nuclei far off stability for which no experimental cross sections are known. Therefore, one has to rely on theory. The difficulties in the predictions are briefly addressed. To investigate the impact of altered rates, a comparison of r-process production in hot bubble models with largely varied rates is shown. Due to the (n,gamma)-(gamma,n) equilibrium established at the onset of the r-process, only late-time neutron captures are important which mainly modify the abundances around the third r-process peak.

T. Rauscher

2004-04-12

2

Fission cycling in a supernova r process  

SciTech Connect

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

Beun, J.; McLaughlin, G. C.; Surman, R.; Hix, W. R. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27595-8202 (United States); Department of Physics, Union College, Schenectady, New York 12308 (United States); Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6374 (United States)

2008-03-15

3

Superheavy elements and r-process  

SciTech Connect

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

Panov, I. V., E-mail: Igor.Panov@itep.ru; Korneev, I. Yu. [Institute of Theoretical and Experimental Physics (Russian Federation); Thielemann, F.-K. [Institut fuer Physik der Universitaet Basel (Switzerland)

2009-06-15

4

Multidimensional Point Process Models in R  

Microsoft Academic Search

A software package for fitting and assessing multidimensional point process models using the R statistical computing environment is described. Methods of residual analysis based on random thinning are discussed and implemented. Features of the software are demonstrated using data on wildfire occurrences in Los Angeles County, California and earthquake occurrences in Northern California.

Roger D. Peng

2003-01-01

5

Neutron capture in the r-process  

SciTech Connect

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

Surman, Rebecca [Union College; Mclaughlin, Gail C [North Carolina State University; Mumpower, Matthew [North Carolina State University; Hix, William Raphael [ORNL; Jones, K. L. [University of Tennessee, Knoxville (UTK)

2010-01-01

6

The Rare Earth Peak : An Overlooked r-Process Diagnostic  

E-print Network

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>100k_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.

M. Mumpower; G. McLaughlin; R. Surman

2012-02-08

7

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

8

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

9

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

10

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

E-print Network

) to investigate technical issues related to treatment processes for low-level radioactive and mixed wastes and solidification processes in order to consider the appropriateness of several processes for specific low-levelEPA 402-R-96-014 June 1996 STABILIZATION/SOLIDIFICATION PROCESSES FOR MIXED WASTE Center

11

R-process nucleosynthesis calculations with complete nuclear physics input  

E-print Network

The r-process constitutes one of the major challenges in nuclear astrophysics. Its astrophysical site has not yet been identified but there is observational evidence suggesting that at least two possible sites should contribute to the solar system abundance of r-process elements and that the r-process responsible for the production of elements heavier than Z=56 operates quite robustly producing always the same relative abundances. From the nuclear-physics point of view the r-process requires the knowledge of a large number of reaction rates involving exotic nuclei. These include neutron capture rates, beta-decays and fission rates, the latter for the heavier nuclei produced in the r-process. We have developed for the first time a complete database of reaction rates that in addition to neutron-capture rates and beta-decay half-lives includes all possible reactions that can induce fission (neutron-capture, beta-decay and spontaneous fission) and the corresponding fission yields. In addition, we have implemented these reaction rates in a fully implicit reaction network. We have performed r-process calculations for the neutrino-driven wind scenario to explore whether or not fission can contribute to provide a robust r-process pattern.

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

2008-12-04

12

Precipitation processes in the Middle East , R. Smitha  

E-print Network

Precipitation processes in the Middle East J. Evansa , R. Smitha and R.Oglesbyb a Dept. Geology and topography in generating precipitation in the Middle East. The model is run for five years (1990 thru 1994 that exhibit precipitation regimes disparate from one-another are identified and examined. The models ability

Evans, Jason

13

R&D project selection using the analytic network process  

Microsoft Academic Search

The analytic network process (ANP) is presented as a potentially valuable method to support the selection of projects in a research and development (R&D) environment. This paper first discusses the requirements of the R&D project selection problem, which requires the allocation of resources to a set of competing and often disparate project proposals. Among the factors complicating this task is

Laura M. Meade; Adrien Presley

2002-01-01

14

Approaching r-process nuclei at N = 126  

NASA Astrophysics Data System (ADS)

The production of heavy neutron-rich nuclei approaching the r-process waiting point at N?126 has been investigated in fragmentation reactions of relativistic 238U and 208Pb projectiles. Using this technique we were able to identify 73 new heavy neutron-rich nuclei expanding considerably the north-west frontier of the chart of nuclide. Moreover, we were able to determine the half lives of 13 of those nuclides. The measured values are significantly shorter than the predictions used for r-process model calculations. These shorter half lives are understood as due to the role of first-forbidden transitions in the decays of these nuclei. The confirmation of these results for r-process nuclei at N?126 would indicate that the r-process at this point is faster than expected, leading to a larger production of the heaviest nuclei.

Benlliure, J.; Alvarez-Pol, H.; Kurtukian-Nieto, T.; Morales, A. I.; Audouin, L.; Becker, F.; Blank, B.; Borzov, I.; Casarejos, E.; Cortina-Gil, D.; Fernandez, B.; Giovinazzo, J.; Henzlova, D.; Jurado, B.; Langanke, L.; Martinez-Pinedo, G.; Napolitani, P.; Pereira, J.; Rejmund, F.; Schmidt, K.-H.; Yordanov, O.; RISING Collaboration

2012-02-01

15

The r-process nucleosynthesis: Nuclear physics challenges  

SciTech Connect

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

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

2012-10-20

16

Fission Cycling in a Supernova r-Process  

SciTech Connect

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

Beun, Joshua [North Carolina State University; Mclaughlin, Gail C [North Carolina State University; Surman, Rebecca [Union College; Hix, William Raphael [ORNL

2008-01-01

17

The r-process in the early Galaxy  

E-print Network

We report Sr, Pd and Ag abundances for a sample of metal-poor field giants and analyze a larger sample of Y, Zr, and Ba abundances. The [Y/Zr] and [Pd/Ag] abundance ratios are similar to those measured for the r-process-rich stars CS 22892-052 and CS 31082-001. The [Pd/Ag] ratio is larger than predicted from the solar-system r-process abundances. The constant[Y/Zr] and [Sr/Y] values in the field stars places strong limits on the contributions of the weak s-process and the main s-process to the light neutron-capture elements. Stars in the globular cluster M 15 possess lower [Y/Zr] values than the field stars. There is a large dispersion in [Y/Ba]. Because the r-process is responsible for the production of the heavy elements in the early Galaxy, these dispersions require varying light-to-heavy ratios in r-process yields.

Jennifer A. Johnson; Michael Bolte

2002-08-20

18

The r-Process in Black Hole Winds  

E-print Network

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

Shinya Wanajo; Hans-Thomas Janka

2010-06-11

19

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

NASA Technical Reports Server (NTRS)

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

Meyer, Bradley S.

1994-01-01

20

rTMS over the intraparietal sulcus disrupts numerosity processing  

PubMed Central

It has been widely argued that the intraparietal sulcus (IPS) is involved in tasks that evoke representations of numerical magnitude, among other cognitive functions. However, the causal role of this parietal region in processing symbolic and non-symbolic numerosity has not been established. The current study used repetitive Transcranial Magnetic Stimulation (rTMS) to the left and right IPS to investigate the effects of temporary deactivations of these regions on the capacity to represent symbolic (Arabic numbers) and non-symbolic (arrays of dots) numerosities. We found that comparisons of both symbolic and non-symbolic numerosities were impaired after rTMS to the left IPS but enhanced by rTMS to the right IPS. A signature effect of numerical distance was also found: greater impairment (or lesser facilitation) when comparing numerosities of similar magnitude. The reverse pattern of impairment and enhancement was found in a control task that required judging an analogue stimulus property (ellipse orientation) but no numerosity judgements. No rTMS effects for the numerosity tasks were found when stimulating an area adjacent but distinct from the IPS, the left and right angular gyrus. These data suggest that left IPS is critical for processing symbolic and non-symbolic numerosity; this processing may thus depend on common neural mechanisms, which are distinct from mechanisms supporting the processing of analogue stimulus properties. PMID:17216413

2008-01-01

21

Explosive Nucleosynthesis and the Astrophysical rProcess  

E-print Network

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

Rauscher, Thomas

22

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

23

The p- and r- processes: reviews and other views  

NASA Astrophysics Data System (ADS)

A review is presented of the p-process in Type II supernovae, one of its goals being to enlighten the changes in views on this nucleosynthesis mechanism since the work of Jean and Jim on the subject in 1975. Specific discussions are also devoted to cases of particular interest, like the light Mo and Ru stable isotopes, the rare nuclide 138La or the radionuclide 146Sm. Some comments of diverse natures are also made on the r-process. These considerations do not aim at really providing an exhaustive review of the many nuclear physics and astrophysics intricacies of this process. In contrast, they are hoped to complement or to put in perspective other views that are often expressed in relation with this nucleosynthesis mechanism

Arnould, M.; Goriely, S.; Rayet, M.

24

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

SciTech Connect

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

Panov, I. V., E-mail: Igor.Panov@itep.ru [Institute for Theoretical and Experimental Physics (Russian Federation); Korneev, I. Yu.; Lutostansky, Yu. S. [National Research Center Kurchatov Institute (Russian Federation)] [National Research Center Kurchatov Institute (Russian Federation); Thielemann, F.-K. [University of Basel, Institute of Physics (Switzerland)] [University of Basel, Institute of Physics (Switzerland)

2013-01-15

25

r-process kilonova emission accompanying short-duration GRBs  

NASA Astrophysics Data System (ADS)

Our recent HST observations of the short-duration GRB130603B showed an infrared excess, about ten days after the burst, consistent with expectations from models of an emerging 'kilonova' driven by the radioactive decay of newly-synthesised r-process elements. This directly supports the compact object merger hypothesis for short-duration GRBs, in which ejected neutron star material powers a radioactive transient. The discovery also provides a new, quasi-isotropic, electromagnetic localisation signature of the most promising class of gravitational wave (GW) sources for detection with the next generation of detectors, and suggests that kilonovae of this sort are likely sites of substantial (perhaps dominant) production of r-process elements in the universe. However, the ubiquity and range of behaviour of these events is entirely unknown. We need to establish their properties to inform searches of GW error boxes and quantify their contribution to the heavy element nucleosynthesis budget. Here we propose ToO observations a low-redshift (z<~0.35) SGRB localised during cycle 22 to search for and characterise more fully any similar kilonova signal.

Tanvir, Nial

2014-10-01

26

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

27

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

E-print Network

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

Wai, Ping-kong Alexander

28

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

NASA Astrophysics Data System (ADS)

The chemical abundances of metal-poor stars provide important clues to explore stellar formation history and set significant constraints on models of the r-process. In this work, we find that the abundance patterns of the light and iron group elements of the main r-process stars are very close to those of the weak r-process stars. Based on a detailed abundance comparison, we find that the weak r-process occurs in supernovae with a progenitor mass range of ˜11-26 M?. Using the SN yields given by Heger & Woosley and the abundances of the weak r-process stars, the weak r-process yields are derived. The SNe with a progenitor mass range of 15 M? < M < 26 M? are the main sites of the weak r-process, and their contributions are larger than 80%. Using the abundance ratios of the weak r-process and the main r-process in the solar system, the average yields of the main r-process are estimated. The observed correlations of [neutron-capture/Eu] versus [Eu/Fe] can be explained by mixing of the two r-process abundances in various fractions.

Li, Hongjie; Ma, Wenjuan; Cui, Wenyuan; Zhang, Bo

2014-06-01

29

Formation Of The Rare Earth Peak: Gaining Insight Into Late-Time r-Process Dynamics  

E-print Network

We study the formation and final structure of the rare earth peak ($A\\sim160$) of the $r$-process nucleosynthesis. The rare earth peak forms at late times in the $r$-process after neutron exhaustion (neutron-to-seed ratio unity or R=1) as matter decays back to stability. Since rare earth peak formation does not occur during \

Matthew Mumpower; Gail McLaughlin; Rebecca Surman

2011-09-16

30

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

E-print Network

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

Mumpower, M; Aprahamian, A

2014-01-01

31

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

E-print Network

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

M. Mumpower; R. Surman; A. Aprahamian

2014-11-14

32

On the Site of the Weak rProcess Component #  

E-print Network

field stars, are generally assumed to have been synthesized in an environment tied to massive stars (M in the mass range through uranium and thorium are generally understood, the details remain to be worked out the region of #­stability ­ and with the characteristics of the stellar or supernova environments in which r

Cowan, John

33

Enrichment history of r-process elements shaped by a merger of neutron star pairs  

E-print Network

The origin of r-process elements remains unidentified and still puzzles us. The recent discovery of evidence for the ejection of r-process elements from a short-duration gamma-ray burst singled out neutron star mergers (NSMs) as their origin. In contrast, core-collapse supernovae are ruled out as the main origin of heavy r-process elements (A>110) by recent numerical simulations. However, the properties characterizing NSM events - their rarity and high yield of r-process elements per event - have been claimed to be incompatible with the observed stellar records on r-process elements in the Galaxy. We add to this picture with our results, which show that the observed constant [r-process/H] ratio in faint dwarf galaxies and one star unusually rich in r-process in the Sculptor galaxy agree well with this rarity of NSM events. Furthermore, we found that a large scatter in the abundance ratios of r-process elements to iron in the Galactic halo can be reproduced by a scheme that incorporates an assembly of various ...

Tsujimoto, Takuji

2014-01-01

34

Coalescing Neutron Stars: A Solution to the R-Process Problem?  

E-print Network

Recent calculations place questions on the ability of supernovae to produce r-process nuclei in the correct amounts. We present results from 3D Newtonian SPH calculations of mergers of equal mass neutron star binaries. We find the amounts of ejected mass to be very promising for an explanation of the observed r-process abundances. Preliminary abundance calculations show that practically all the material is subject to r-process conditions. The calculated abundance patterns reproduce the basic features of the solar r-process abundances very well. Especially the peak around A= 195 is easily reproduced without any tuning of the initial entropies. Thus, eventually all the observed r-process material could be explained by mass ejection during neutron star mergers.

S. Rosswog; F. -K. Thielemann; M. B. Davies; W. Benz; T. Piran

1998-04-30

35

r-Process Nucleosynthesis in Black Hole-Neutron Star Mergers  

SciTech Connect

Compact object mergers have long been speculated to be a possible site of r-process nucleosynthesis. While most attention has been focused on the cold decompression of neutron star matter ejected from the merger, other sites within the merger likely contribute to its nucleosynthetic output. Here we consider hot outflows from the accretion disk that forms around the black hole following a black hole- neutron star merger. We begin with the results of a three-dimensional numerical merger model and carefully calculate the neutrino and antineutrino fluxes emitted from the accretion disk. We find that neutrino interactions on free nucleons in the outflowing material result in neutron excesses such that at least a weak r-process is produced and in some cases a main r-process as well. Additionally, we find that the weak r-process pattern calculated for certain trajectories compares favorably to the pattern observed in a weak r-process-enhanced halo star.

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

36

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

NASA Astrophysics Data System (ADS)

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

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

2007-09-01

37

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

38

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

E-print Network

the First Industrial Energy Technology Conference Houston, TX, April 22-25, 1979 processes. I i How does this affect industry? It places on industry the burden of disCerni1g those major sources of high priced fuel savings available in the near future... the First Industrial Energy Technology Conference Houston, TX, April 22-25, 1979 processes. I i How does this affect industry? It places on industry the burden of disCerni1g those major sources of high priced fuel savings available in the near future...

Sheneman, R. L.

1979-01-01

39

Neutrino-induced neutron spallation and the site of the r-process  

Microsoft Academic Search

All of the actinides and roughly half the natural abundance of elements with mass number A > 70 come from the rapid neutron capture process, or the r-process. If the r-process, as suggested by many, occurs deep in a supernova, then it is under the influence of an intense neutrino flux. Here we discuss the effects of both charged-current and

Yong-Zhong Qian

1997-01-01

40

Efficient Processing of Spatial Joins Using R-Trees  

Microsoft Academic Search

Spatial joins are one of the most important operations for combin- ing spatial objects of several relations. The efficient processing of a spatial join is extremely important since its execution time is super- linear in the number of spatial objects of the participating relations, and this number of objects may be very high. In this paper, we present a first

Thomas Brinkhoff; Hans-Peter Kriegel; Bernhard Seeger

1993-01-01

41

Sensitivity of r-Process Nucleosynthesis to Light-Element Nuclear Reactions  

E-print Network

We study the efficiency and sensitivity of r-process nucleosynthesis to 18 light-element nuclear reaction rates. We adopt empirical power-law relations to parameterize the reaction sensitivities. We utilize two different hydrodynamic models for the neutrino-driven winds in order to study the dependence of our result on supernova wind models. We also utilize an exponential model to approximate a wide variety of other plausible conditions for the r-process. We identify several specific nuclear reactions among light neutron-rich nuclei that play a critical role in determining the final r-process nucleosynthesis yields. As an illustration, we examine ``semi-waiting'' points among the carbon isotopes. We show that not only neutron capture and $\\beta$-decay, but also $(\\alpha, \\mathrm{n})$ reactions are important in determining waiting points along the r-process path. Our numerical results from this sensitivity analysis serve foremost to clarify which light nuclear reactions are most influential in determining the final r-process abundances. We also quantify the effects of present nuclear uncertainties on the final r-process abundances. This study thus emphasizes and motivates which future determinations of nuclear reaction rates will most strongly impact our understanding of r-process nucleosynthesis.

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

2005-04-24

42

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

43

Local and global effects of beta decays on r-process  

E-print Network

Nuclear beta decay rates are an essential ingredient in simulations of the astrophysical r-process. Most of these rates still rely on theoretical modeling. However, modern radioactive ion-beam facilities have allowed to measure beta half lives of some nuclei on or close to the r-process path. These data indicate that r-process half lives are in general shorter than anticipated in the standard theoretical predictions based on the Finite Range Droplet Model (FRDM). The data have also served as important constraints for improved predictions of half lives based on continuum QRPA calculations on top of the energy-density functional theory. Although these calculations are yet limited to spherical nuclei, they include the important r-process waiting point nuclei close to and at the neutron magic numbers $N=50, 82$ and 126. We have studied the impact of these new experimental and theoretical half lives on r-process nucleosynthesis within the two astrophysical sites currently favored for the r process: the neutrino-driven wind from the freshly born neutron star in a supernova explosion and the ejecta of the merger of two neutron stars. We find that the, in general, shorter beta decay rates have several important effects on the dynamics of r-process nucleosynthesis. At first, the matter flow overcomes the waiting point nuclei faster enhancing matter transport to heavier nuclei. Secondly, the shorter half lives result also in a faster consumption of neutrons resulting in important changes of the conditions at freeze-out with consequences for the final r-process abundances. Besides these global effects on the r-process dynamics, the new half lives also lead to some local changes in the abundance distributions.

O. L. Caballero; A. Arcones; I. N. Borzov; K. Langanke; G. Martinez-Pinedo

2014-05-01

44

The impact of nuclear masses near $N=82$ on $r$-process abundances  

E-print Network

We have performed for the first time a complete $r$-process mass sensitivity study in the $N=82$ region. We take into account how an uncertainty in a single nuclear mass propagates to influence important quantities of neighboring nuclei, including Q-values and reaction rates. We demonstrate that nuclear mass uncertainties of $\\pm0.5$ MeV in the $N=82$ region result in up to an order of magnitude local change in $r$-process abundance predictions. We identify key nuclei in the study whose mass has a substantial impact on final $r$-process abundances and could be measured at future radioactive beam facilities.

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

2014-01-01

45

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

E-print Network

The oldest stars born before the onset of the main s-process are expected to reveal a pure r-process Ba/Eu abundance ratio. We revised barium and europium abundances of selected very metal-poor (VMP) and strongly r-process enhanced (r-II) stars to evaluate an empirical r-process Ba/Eu ratio. Our calculations were based on non-local thermodynamic equilibrium (NLTE) line formation for Ba II and Eu II in the classical 1D MARCS model atmospheres. Homogeneous stellar abundances were determined from the Ba II subordinate and resonance lines by applying a common Ba isotope mixture. We used high-quality VLT/UVES spectra and observational material from the literature. For most investigated stars, NLTE leads to a lower Ba, but a higher Eu abundance. The resulting elemental ratio of the NLTE abundances amounts, on average, log(Ba/Eu) = 0.78+-0.06. This is a new constraint to pure r-process production of Ba and Eu. The obtained Ba/Eu abundance ratio of the r-II stars supports the corresponding Solar System r-process rati...

Mashonkina, Lyudmila

2014-01-01

46

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

47

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

48

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

E-print Network

Physical processes and hypoxia in the central basin of Lake Erie Yerubandi R. Rao1 Environment, Burlington, Ontario L7R 4A6, Canada Nathan Hawley NOAA­Great Lakes Environmental Research Laboratory, 2205 stratification were examined using time-series data of horizontal velocity, temperature, and dissolved oxygen

49

Effects of Acquisitions on Product and Process Innovation and R&D Performance  

Microsoft Academic Search

Using a game theoretical model on firms' simultaneous investments in product and process innovation, we deduct and empirically test hypotheses on the optimal R&D portfolio, investment, performance, and dynamic efficiency of R&D for acquisitions and in independently competing firms. We use Community Innovation Survey data on Italian manufacturing firms. Theoretical and empirical results show that firms involved in acquisitions invest

Elena Cefis; Stephanie Rosenkranz; Utz Weitzel

2005-01-01

50

Ris-R-1570(EN) A development process meta-model  

E-print Network

Risø-R-1570(EN) A development process meta-model for Web based expert systems: the Web engineering 2006 #12;Author: Ioannis M. Dokas & Alexandre Alapetite Title: A development process meta-model for Web and successful Web based expert systems? In an attempt to answer this question, a development process meta

51

Exploration and exploitation innovation processes: The role of organizational slack in R & D intensive firms  

Microsoft Academic Search

This study considers how organizational slack (available and recoverable) affects the process of innovation by facilitating or hindering the process of exploration and exploitation in the case of technology intensive firms. It is argued that the R & D intensity of the firm moderates the effect of organizational slack on innovation quantity, innovation quality as well as the process of

Scott W. Geiger; Marianna Makri

2006-01-01

52

r-process nucleosynthesis in the high-entropy supernova bubble  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

53

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

54

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

E-print Network

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

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

2005-07-17

55

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

E-print Network

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, ...

Roederer, Ian U.

56

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

57

Neutrino-induced neutron spallation and supernova r-process nucleosynthesis  

Microsoft Academic Search

It is likely that the site of the {ital r} process is the hot, neutron-rich {open_quotes}bubble{close_quotes} that expands off a protoneutron star during a core-collapse supernova. The r process would then occur in an intense flux of neutrinos. In order to explore the consequences of the neutrino irradiation, we calculate the rates of charged-current and neutral-current neutrino reactions on neutron-rich

Y.-Z. Qian; P. Vogel; W. C. Haxton; K. Langanke

1997-01-01

58

Neutrino-induced neutron spallation and supernova r-process nucleosynthesis  

Microsoft Academic Search

It is quite likely that the site of the r process is the hot, neutron-rich ``bubble'' that expands off a protoneutron star during a core-collapse supernova. The r process would then occur in an intense flux of neutrinos. In order to explore the consequences of the neutrino irradiation, we calculate the rates of charged-current and neutral-current neutrino reactions on neutron-rich

Y.-Z. Qian; W. C. Haxton; K. Langanke; P. Vogel

1997-01-01

59

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

E-print Network

The r-process, or the rapid neutron-capture process, of stellar nucleosynthesis is called for to explain the production of the stable (and some long-lived radioactive) neutron-rich nuclides heavier than iron that are observed in stars of various metallicities, as well as in the solar system. A very large amount of nuclear information is necessary in order to model the r-process. This concerns the static characteristics of a large variety of light to heavy nuclei between the valley of stability and the vicinity of the neutron-drip line, as well as their beta-decay branches or their reactivity. The enormously challenging experimental and theoretical task imposed by all these requirements is reviewed, and the state-of-the-art development in the field is presented. Nuclear-physics-based and astrophysics-free r-process models of different levels of sophistication have been constructed over the years. We review their merits and their shortcomings. For long, the core collapse supernova of massive stars has been envisioned as the privileged r-process location. We present a brief summary of the one- or multidimensional spherical or non-spherical explosion simulations available to-date. Their predictions are confronted with the requirements imposed to obtain an r-process. The possibility of r-nuclide synthesis during the decompression of the matter of neutron stars following their merging is also discussed.

M. Arnould; S. Goriely; K. Takahashi

2007-05-31

60

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

E-print Network

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

Cowan, John

61

3D VISUALIZATION OF CONSTRUCTION PROCESSES AND Vineet R. Kamat1  

E-print Network

. In the construction industry, complex decisions yielding maximum benefit are an essential component of process design construction, such as in the manufacturing and service industries. Construction simulation model developers3D VISUALIZATION OF CONSTRUCTION PROCESSES AND PRODUCTS Vineet R. Kamat1 , Julio C. Martinez2 1

Kamat, Vineet R.

62

A Simple Model for r-Process Scatter and Halo Evolution  

E-print Network

Recent observations of heavy elements produced by rapid neutron capture (r-process) in the halo have shown a striking and unexpected behavior: within a single star, the relative abundances of r-process elements heavier than Eu are the same as the same as those of solar system matter, while across stars with similar metallicity Fe/H, the r/Fe ratio varies over two orders of magnitude. In this paper we present a simple analytic model which describes a star's abundances in terms of its ``ancestry,'' i.e., the number of nucleosynthesis events (e.g., supernova explosions) which contributed to the star's composition. This model leads to a very simple analytic expression for the abundance scatter versus Fe/H, which is in good agreement with the data and with more sophisticated numerical models. We investigate two classes of scenarios for r-process nucleosynthesis, one in which r-process synthesis events occur in only \\sim 4% of supernovae but iron synthesis is ubiquitous, and one in which iron nucleosynthesis occurs in only about 9% of supernovae. (the Wasserburg- Qian model). We find that the predictions in these scenarios are similar for [Fe/H] \\ga -2.5, but that these models can be readily distinguished observationally by measuring the dispersion in r/Fe at [Fe/H] \\la -3.

Brian D. Fields; James W. Truran; John J. Cowan

2001-03-06

63

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

64

Cross sections and fragment distributions from neutrino-induced fission on r-process nuclei  

NASA Astrophysics Data System (ADS)

We study neutrino-induced processes that might contribute to the observed patterns in the r-process abundances in low-metallicity, old galactical halo stars. The neutrino-nucleus interaction is calculated within the random phase approximation, while the decay of excited levels in the daughter nucleus is followed via the evaporation-fission code ABLA. We calculate the fission cross sections for selected neutron-rich progenitor nuclei with Z>80. More importantly, we calculate the mass and charge distributions of the fission fragments as well as the number of neutrons set free in the neutrino-induced reactions. We particularly study a sample of nuclei with A>200 representing r-process progenitors during their decay towards the valley of stability after the r-process freeze-out.

Keli?, A.; Zinner, N.; Kolbe, E.; Langanke, K.; Schmidt, K.-H.

2005-06-01

65

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

NASA Technical Reports Server (NTRS)

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.

1986-01-01

66

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

67

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

SciTech Connect

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

Goriely, Stephane [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, C.P. 226, B-1050 Brussels (Belgium); Bauswein, Andreas; Janka, Hans-Thomas [Max-Planck-Institut fuer Astrophysik, Postfach 1317, D-85741 Garching (Germany)

2011-09-10

68

Nuclear masses near $N=82$ that influence $r$-process abundances  

E-print Network

Nuclear masses are one of the key ingredients of nuclear physics that go into astrophysical simulations of the $r$ process. Nuclear masses effect $r$-process abundances by entering into calculations of Q-values, neutron capture rates, photo-dissociation rates, beta-decay rates, branching ratios and the properties of fission. Most of the thousands of short-lived neutron-rich nuclei which are believed to participate in the $r$ process lack any experimental verification, thus the identification of the most influential nuclei is of paramount importance. We have conducted mass sensitivity studies near the $N=82$ closed shell in the context of a main $r$-process. Our studies take into account how an uncertainty in a single nuclear mass propagates to influence the relevant quantities of neighboring nuclei and finally to $r$-process abundances. We identify influential nuclei in various astrophysical conditions using the FRDM mass model. We show that our conclusions regarding these key nuclei are still retained when a...

Mumpower, M; Beard, M; Fang, D -L; Aprahamian, A

2014-01-01

69

Efficient Searches for r-Process-Enhanced, Metal-Poor Stars  

NASA Astrophysics Data System (ADS)

Neutron-capture-enhanced, metal-poor stars are of central importance to developing an understanding of the operation of the r-process in the early Galaxy, thought to be responsible for the formation of roughly half of all elements beyond the iron peak. A handful of neutron-capture-rich, metal-poor stars with [Fe/H]<-2.0 have already been identified, including the well known r-process-enhanced stars CS 22892-052 and CS 31082-001. However, many questions of fundamental interest can only be addressed with the assemblage of a much larger sample of such stars, so that general properties can be distinguished. We describe a new effort, HERES: The Hamburg/ESO R-Process-Enhanced Star survey, nearing completion, which will identify on the order of 5 10 additional highly r-process-enhanced, metal-poor stars, and in all likelihood, a similar or greater number of mildly r-process-enhanced, metal-poor stars in the halo of the Galaxy. HERES is based on rapid “snapshot” spectra of over 350 candidate halo giants with [Fe/H]<-2.0, obtained at moderately high resolution, and with moderate signal-to-noise ratios, using the UVES spectrograph on the European VLT 8m telescope.

Beers, T. C.; Barklem, P. S.; Christlieb, N.; Hill, V.

2005-07-01

70

R&D Spillovers: Evidence from U.S. Food Processing, Farm Machinery and Agricultural Sectors  

Microsoft Academic Search

This paper computes private and social rates of return to R&D capital in the three vertically linked sectors, primary agriculture, food processing, and the farm machinery in the United States. Using a cost function approach, the private rates of return to R&D ranged from an average of 21.5% per annum for farm machinery to 87.5% for agriculture. The social rates

Munisamy Gopinath; Terry L. Roe

2000-01-01

71

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

72

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

73

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

74

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

75

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

2013-10-22

76

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

PubMed Central

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

2013-01-01

77

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

E-print Network

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

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

2009-01-13

78

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

SciTech Connect

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

Beun, Joshua [North Carolina State University; Blackmon, Jeffery C [Louisiana State University; Hix, William Raphael [ORNL; Mclaughlin, Gail C [North Carolina State University; Smith, Michael Scott [ORNL; Surman, Rebecca [Union College

2009-01-01

79

Long, Cold, Early r Process? Neutrino-Induced Nucleosynthesis in He Shells Revisited  

SciTech Connect

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

Banerjee, Projjwal; Qian Yongzhong [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Haxton, W. C. [Department of Physics, University of California, and Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2011-05-20

80

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

81

The even-odd systematics in R-process nuclide abundances  

NASA Technical Reports Server (NTRS)

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

Marti, K.; Suess, H. E.

1988-01-01

82

RadioAstron data processing at the MPIfR DiFX correlator  

NASA Astrophysics Data System (ADS)

The Max Planck Institute for RadioAstronomy (MPIfR) is actively participating in the processing and analysis of the RadioAstron mission data. During AO-1, more than 10 MPI-based projects will be observed, and correlated in Bonn. The in-house High Performance Cluster (HPC) is currently running a customized version of the DiFX, able to handle mission's data. I will give a review on the status of the correlator and data processing.

Bruni, Gabriele

83

DETERMINATION OF IONIC TRANSPORT PROCESSES IN AgCl AND AgBr R. J. FRIAUF  

E-print Network

1077 DETERMINATION OF IONIC TRANSPORT PROCESSES IN AgCl AND AgBr R. J. FRIAUF Dept. of Physics constante diélectrique peut donner au mieux une explication qualitative. Il faudrait un meilleur calcul a fraction of the total effect, and a rough calculation shows that the unusual rise in the dielectric

Boyer, Edmond

84

On the robustness of the r-process in neutron-star mergers  

E-print Network

We have performed r-process simulations for a set of trajectories describing matter ejected in neutron star mergers. Our calculations consider an extended nuclear network, including spontaneous, $\\beta$- and neutron-induced fission and adopting fission yield distributions from the ABLA code. In particular we have studied the sensitivity of the r-process abundances on the nuclear mass models by using different models. We find that the general features of the observed r-process abundance distribution (the second and third peaks, the rare-earth peak and the lead peak) are reproduced by our simulations, independently of the merger trajectory, and for all mass models. We find distinct differences in the predictions of the mass models at and just above the third peak, which can be traced back to different predictions of neutron separation energies for r-process nuclei around neutron number N=130. In all simulations, we find that the second peak around $A\\sim 130$ is produced by the fission yields of the material th...

Mendoza-Temis, Joel de Jesús; Langanke, K; Bauswein, A; Janka, H -T

2014-01-01

85

Opacities and Spectra of the r-process Ejecta from Neutron Star Mergers  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

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 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

87

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, T. C.; Chistlieb, N.; Bessell, M. S.; Hill, V.; Barklem, P. S.; Ryan, S. G.; Rossi, S.; Korn, A.

88

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

E-print Network

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

G. Cescutti

2007-02-21

89

Wire transfer of charge packets for on--chip CCD signal processing Eric R. Fossum  

E-print Network

Wire transfer of charge packets for on--chip CCD signal processing Eric R. Fossum Department. The structure is a hybrid of charge-coupled device (CCD) and bucket-brigade device (BBD) elements and permits of the signal quantities is adequate. Charge-domain circuits, such as CCD5, have the added advantages

Fossum, Eric R.

90

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

91

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

92

On the robustness of the r-process in neutron-star mergers  

E-print Network

We have performed r-process simulations for a set of trajectories describing matter ejected in neutron star mergers. Our calculations consider an extended nuclear network, including spontaneous, $\\beta$- and neutron-induced fission and adopting fission yield distributions from the ABLA code. In particular we have studied the sensitivity of the r-process abundances on the nuclear mass models by using different models. We find that the general features of the observed r-process abundance distribution (the second and third peaks, the rare-earth peak and the lead peak) are reproduced by our simulations, independently of the merger trajectory, and for all mass models. We find distinct differences in the predictions of the mass models at and just above the third peak, which can be traced back to different predictions of neutron separation energies for r-process nuclei around neutron number N=130. In all simulations, we find that the second peak around $A\\sim 130$ is produced by the fission yields of the material that piles up in nuclei with $A\\gtrsim 250$ due to the substantially longer beta-decay half-lives found in this region. The third peak around $A \\sim 195$ is generated in a competition between neutron captures and $\\beta$ decays during r-process freeze-out. We find that at timescales of weeks relevant for kilonova light curve calculations, the abundance of actinides is larger than the one of lanthanides. This means that actinides can be even more important than lanthanides to determine the photon opacities under kilonova conditions.

Joel de Jesús Mendoza-Temis; G. Martínez-Pinedo; K. Langanke; A. Bauswein; H. -T. Janka

2014-09-22

93

Half Life of the Doubly-magic r-Process Nucleus 78Ni  

E-print Network

Nuclei with magic numbers serve as important benchmarks in nuclear theory. In addition, neutron-rich nuclei play an important role in the astrophysical rapid neutron-capture process (r-process). 78Ni is the only doubly-magic nucleus that is also an important waiting point in the r-process, and serves as a major bottleneck in the synthesis of heavier elements. The half-life of 78Ni has been experimentally deduced for the first time at the Coupled Cyclotron Facility of the National Superconducting Cyclotron Laboratory at Michigan State University, and was found to be 110 (+100 -60) ms. In the same experiment, a first half-life was deduced for 77Ni of 128 (+27 -33) ms, and more precise half-lives were deduced for 75Ni and 76Ni of 344 (+20 -24) ms and 238 (+15 -18) ms respectively.

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

2005-04-04

94

Production of all the r-process nuclides in the dynamical ejecta of neutron star mergers  

E-print Network

Recent studies suggest that binary neutron star (NS-NS) mergers robustly produce the heavy r-process nuclei above the atomic mass number of A ~ 130 because of their ejecta consisting of almost pure neutrons (electron fraction of Y_e heated and neutrino-processed, resulting in a wide range of Y_e (= 0.09-0.45). The mass-averaged abundance distribution of calculated nucleosynthesis yields is in remarkable agreement with the full-mass range (A = 90-240) of the solar r-process curve. This implies, if our model is representative of such events, that the dynamical ejecta of NS-NS mergers can be th...

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

2014-01-01

95

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

96

R-Process Abundances and Chronometers in Metal-poor Stars  

Microsoft Academic Search

Rapid neutron-capture (i.e., r-process) nucleosynthesis calculations, employing internally consistent and physically realistic nuclear physics input (quasi-particle random-phase approximation [QRPA] beta-decay properties and the recent extended Thomas-Fermi with Strutinsky integral and quenching (ETFSI-Q) nuclear mass model), have been performed. These theoretical computations assume the classical waiting-point approximation of (n,gamma)&rlarr2;(gamma,n) equilibrium. The calculations reproduce the solar isotopic r-abundances in detail, including the

John J. Cowan; B. Pfeiffer; K.-L. Kratz; Christopher Sneden; Scott Burles; David Tytler; Timothy C. Beers

1999-01-01

97

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

E-print Network

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

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

2013-11-22

98

Implications of GRB 130603B and its macronova for r-process nucleosynthesis  

E-print Network

The tentative identification of a Li-Paczynski macronova following the short GRB 130603B indicated that a few hundredths of a solar mass of neutron star matter were ejected and that this ejected mass has radioactively decayed into heavy r-process elements. If correct, this confirms long standing predictions (Eichler, Livio, Piran and Schramm 1989) that on the one hand, sGRBs are produced in compact binary mergers (CBMs) and on the other hand that these events are significant and possibly dominant sources of the heavy (A>130) r-process nuclei. Assuming that this interpretation is correct we obtain a lower limit of 0.02 m_sun on the ejected mass. Using the current estimates of the rate of sGRBs and with a beaming factor of 50, mergers associated with sGRBs can produce all the observed heavy r-process material in the Universe. We confront this conclusion with cosmochemistry and show that even though such events are rare, mixing is sufficient to account for the current homogeneous distribution of r-process material in the Galaxy. However, the appearance of significant amounts of Eu in some very low metallicity stars requires that some mergers took place very early on, namely with a very short time delay after the earliest star formation episodes. Alternatively, an additional early r-processsource may have contributed at that early stage. Finally, we note that evidence for short lived {244}^Pu in the very early solar system suggests that a merger of this kind took place within the vicinity of the solar system shortly (a few hundred million years) before its formation.

Tsvi Piran; Oleg Korobkin; Stephan Rosswog

2014-01-09

99

Heat shock inhibits pre-rRNA processing at the primary site in vitro and alters the activity of some rRNA binding proteins.  

PubMed

The effect of heat shock on pre-rRNA processing at the primary site within external transcribed spacer region 1 (ETS1) was studied in S-100 extract derived from mouse lymphosarcoma cells. In vivo labeling with [32P]orthophosphate showed that the synthesis of the rRNA precursor and its processing to 28S and 18S rRNAs were inhibited significantly due to heat shock. The processing activity was reduced by 50% at 1 h and was completely blocked following 2-h exposure of cells at 42 degrees C. Mixing S-100 extracts from the control and heat-treated cells did not affect the processing activity in the control extract, which proves the absence of a nuclease or other inhibitor(s) of processing in the extract from the heat-shocked cells. Heat shock did not affect interaction between pre-rRNA and U3 snoRNA, a prerequisite for the processing at the primary site, but significantly altered RNA-protein interaction. Three polypeptides of 200, 110, and 52 kDa that specifically cross-link to pre-rRNA spanning the primary processing site were inactivated after heat shock. Hyperthermia did not alter 3' end processing of SV40L pre-mRNA. PMID:8891896

Ghoshal, K; Jacob, S T

1996-09-15

100

IL-4R?-Associated Antigen Processing by B Cells Promotes Immunity in Nippostrongylus brasiliensis Infection  

PubMed Central

In this study, B cell function in protective TH2 immunity against N. brasiliensis infection was investigated. Protection against secondary infection depended on IL-4R? and IL-13; but not IL-4. Protection did not associate with parasite specific antibody responses. Re-infection of B cell-specific IL-4R??/? mice resulted in increased worm burdens compared to control mice, despite their equivalent capacity to control primary infection. Impaired protection correlated with reduced lymphocyte IL-13 production and B cell MHC class II and CD86 surface expression. Adoptive transfer of in vivo N. brasiliensis primed IL-4R? expressing B cells into naïve BALB/c mice, but not IL-4R? or IL-13 deficient B cells, conferred protection against primary N. brasiliensis infection. This protection required MHC class II compatibility on B cells suggesting cognate interactions by B cells with CD4+ T cells were important to co-ordinate immunity. Furthermore, the rapid nature of these protective effects by B cells suggested non-BCR mediated mechanisms, such as via Toll Like Receptors, was involved, and this was supported by transfer experiments using antigen pulsed Myd88?/? B cells. These data suggest TLR dependent antigen processing by IL-4R?-responsive B cells producing IL-13 contribute significantly to CD4+ T cell-mediated protective immunity against N. brasiliensis infection. PMID:24204255

Hoving, Jennifer C.; Nieuwenhuizen, Natalie; McSorley, Henry J.; Ndlovu, Hlumani; Bobat, Saeeda; Kimberg, Matti; Kirstein, Frank; Cutler, Anthony J.; DeWals, Benjamin; Cunningham, Adam F.; Brombacher, Frank

2013-01-01

101

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

E-print Network

Balancing SoNaR: IPR versus Processing Issues in a 500-Million-Word Written Dutch Reference Corpus included in SoNaR will have its IPR issues settled to the largest extent possible. This data collection lead to the creation of two corpora: a gigaword SoNaR, IPR-cleared for research purposes

Tilburg, Universiteit van

102

?-delayed neutron emission measurements around the third r-process abundance peak  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

103

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

104

N=82 shell quenching of the classical r-process "waiting-point" nucleus 130Cd.  

PubMed

First beta- and gamma-spectroscopic decay studies of the N=82 r-process "waiting-point" nuclide 130Cd have been performed at CERN/ISOLDE using the highest achievable isotopic selectivity. Several nuclear-physics surprises have been discovered. The first one is the unanticipatedly high energy of 2.12 MeV for the [pi g(9/2) multiply sign in circle nu g(7/2)] 1(+) level in 130In, which is fed by the main Gamow-Teller transition. The second surprise is the rather high Q(beta) value of 8.34 MeV, which is in agreement only with recent mass models that include the phenomenon of N=82 shell quenching. Possible implications of these new results on the formation of the A approximately 130 r-process abundance peak are presented. PMID:14611397

Dillmann, I; Kratz, K-L; Wöhr, A; Arndt, O; Brown, B A; Hoff, P; Hjorth-Jensen, M; Köster, U; Ostrowski, A N; Pfeiffer, B; Seweryniak, D; Shergur, J; Walters, W B

2003-10-17

105

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

SciTech Connect

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

Kozub, R. L. [Tennessee Technological University; Bardayan, Daniel W [ORNL; Adekola, Aderemi S [ORNL; Blackmon, Jeff C [ORNL; Chae, K. Y. [University of Tennessee; Chipps, K. [Colorado School of Mines, Golden; Cizewski, J. A. [Rutgers University; Erikson, Luke [Colorado School of Mines, Golden; Hatarik, Robert [Rutgers University; Jones, K. L. [University of Tennessee; Krolas, W. [University of Warsaw; Liang, J Felix [ORNL; Ma, Zhanwen [ORNL; Matei, Catalin [Oak Ridge Associated Universities (ORAU); Moazen, Brian [University of Tennessee; Nesaraja, Caroline D [ORNL; Pain, Steven D [ORNL; Shapira, Dan [ORNL; ShrinerJr., J. F. [Tennessee Technological University; Smith, Michael Scott [ORNL; Swan, T. P. [University of Surrey, UK

2009-01-01

106

Weak Interaction Rates of Nuclei Near the R-Process Paths  

NASA Astrophysics Data System (ADS)

Systematic calculations of the beta- and neutrino-induced rates are performed for the nuclei at Z=92-96 approaching the possible r-process paths in vicinity of the spherical neutron shell at N=184. The nuclear ground states are treated self-consistently in the framework of the local energy-density functional (DF) theory. The beta-strength-functions of the Gamow-Teller and first-forbidden decays are calculated within the continuum QRPA approach of the finite Fermi system theory. The beta-decay half-lives and beta-delayed neutron emission probabilities are analyzed simultaneously. Within the same approach the weak interaction rates are calculated for the fission products around Z?50, N=82 forming the A=130 peak in the r-process isotopic abundance. A shell-model study of selected Pd isotopes is performed. An analysis of available experimental data and theoretical predictions from the FRDM is also presented.

Borzov, I. N.; Cuenca-Garc?a, J. J.; Langanke, K.; Mart?nez-Pinedo, G.; Keli?, A.; Zinner, N. T.

2007-05-01

107

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

108

On the termination of the r-process and the synthesis of superheavy elements  

Microsoft Academic Search

Predictions for spontaneous and neutron-induced fission, alpha and beta decay have been made on the basis of potential-energy surfaces for Z >= 90 nuclei on the neutron-rich side of the beta stability line. In spite of their considerable quantitive uncertainties, these predictions appear to negate the possibility of superheavy element synthesis via a one- or two-step r-process from super novae.

R. Boleu; S. G. Nilsson; R. K. Sheline; K. Takashashi

1972-01-01

109

THE r-PROCESS IN PROTO-NEUTRON-STAR WIND REVISITED  

SciTech Connect

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

Wanajo, Shinya, E-mail: shinya.wanajo@nao.ac.jp [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2013-06-20

110

Beta-decay rates of nuclei in ground and excited states and effects on the r-process of nucleosynthesis  

NASA Astrophysics Data System (ADS)

Roughly half of all nuclei with mass A > 70 and nearly all of the rare earth elements are produced by two process of neutron capture on lighter nuclei. These processes are called the rapid, or r-, process, and the slow, or s-, process, their names indicative of the rate of neutron captures relative to the stabilizing ?- decays. The r-process must necessarily exist in an environment of high neutron flux. Therefore, nuclei produced in the r-process, which are the progenitors of the stable nuclei observed today, fall along a locus in the very neutron rich region of the isotopic chart known as the r-process path. Progression along the r-process path occurs through a sequence of neutron captures and ?-decays. Since neutron captures are very fast, the r-process is primarily limited by ?-decays. The very neutron-rich nuclei along the r-process path are, for the most part, beyond the reach of experimental physics, despite their importance to modern nuclear astrophysics. Of primary importance in an analysis of r-process nucleosynthesis are the ?-decay half-lives. An alteration in the half-lives can change the path and pace of the r-process. Difficulties in current r-process predictions include the difficulty of current models to manufacture sufficient nuclei in the mass region A~200 region. However, the inclusion of excited state ?-decays may resolve this difficulty by allowing a population of nuclei along the r-process path to speed up the r-process, so that it can move rapidly to the higher masses. The problem is further complicated by the lack of knowledge of many of the r-process progenitor nuclei; indeed, many have not been studied. The theoretical problem of ?-decays of excited state nuclei as well as the production of high mass nuclei via an r-process are both attacked in this work, the results of which are mutually supportive. Future experimentation is discussed as a final note.

Famiano, Michael Andrew

2001-06-01

111

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

112

r-Process abundances in metal-poor Galactic halo stars  

NASA Astrophysics Data System (ADS)

The site of the r-process is not completely defined, and several models try to explain the origin of the trans-Fe elements. Observed abundances are the best clues to bring some light to this multiplicity of possible mechanisms, and the extremely metal-poor (EMP) Galactic halo stars have a special role in this problem. In this contribution we present the solution of a long-standing problem about the origin of the heavy elements in the metal-poor halo subgiant star HD 140283, and its correlation with the Truran's theory. Next, we describe the results obtained with the EMP r-II star CS 31082-001 in the frame of the ESO Large Program ``First Stars''. Using STIS/HST observations we provide abundances for elements never presented before in this stars, making CS 31082-001 the most complete r-II object studied, with a total of 37 detections of neutron-capture elements. Finally, we present the results obtained from a sample of seven r-I stars, showing how those objects can help us solving the heavy elements problem. Conclusions are also described.

Siqueira-Mello, C.; Barbuy, B.; Spite, M.; Spite, F.; Caffau, E.; Hill, V.; Wanajo, S.; François, P.; Bonifacio, P.; Cayrel, R.

113

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

114

Potential Interface between Ribosomal Protein Production and Pre-rRNA Processing?  

PubMed Central

It has become clear that in Saccharomyces cerevisiae the transcription of ribosomal protein genes, which makes up a major proportion of the total transcription by RNA polymerase II, is controlled by the interaction of three transcription factors, Rap1, Fhl1, and Ifh1. Of these, only Rap1 binds directly to DNA and only Ifh1 is absent when transcription is repressed. We have examined further the nature of this interaction and find that Ifh1 is actually associated with at least two complexes. In addition to its association with Rap1 and Fhl1, Ifh1 forms a complex (CURI) with casein kinase 2 (CK2), Utp22, and Rrp7. Fhl1 is loosely associated with the CURI complex; its absence partially destabilizes the complex. The CK2 within the complex phosphorylates Ifh1 in vitro but no other members of the complex. Two major components of this complex, Utp22 and Rrp7, are essential participants in the processing of pre-rRNA. Depletion of either protein, but not of other proteins in the early processing steps, brings about a substantial increase in ribosomal protein mRNA. We propose a model in which the CURI complex is a key mediator between the two parallel pathways necessary for ribosome synthesis: the transcription and processing of pre-rRNA and the transcription of ribosomal protein genes. PMID:17452446

Rudra, Dipayan; Mallick, Jaideep; Zhao, Yu; Warner, Jonathan R.

2007-01-01

115

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

SciTech Connect

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

Suzuki, Toshio [Department of Physics, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550, Japan and Center for Nuclear Study, University of Tokyo, Hirosawa, Wako-shi, Saitama, 351-0198 (Japan); Yoshida, Takashi [Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Utsuno, Yutaka [Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Naka-gun, Ibaraki 319-1195 (Japan)

2010-08-12

116

Expected Limits on R-symmetric $?\\to e $ Processes at Project X  

E-print Network

We investigate $\\mu \\to e$ processes in the Minimal R-symmetric Standrad Model (MRSSM) with the expected limits from Project X. It is found that $\\mu \\to e$ conversion provides the tightest bound on the $\\mu \\to e$ mixing parameters at the order of $\\lesssim O(10^{-3})$. Whereas $\\mu \\to eee$ only slightly improves the bound in the region where incoherence among different contributions to $\\mu \\to e$ is significant. No improvements on the bounds are obtained from $\\mu \\to e \\gamma$.

Ricky Fok

2012-08-31

117

The neutron long counter NERO for studies of ?-delayed neutron emission in the r-process  

NASA Astrophysics Data System (ADS)

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

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

2010-06-01

118

First access to beta half-lives approaching the r-process path near N=126  

E-print Network

Heavy neutron-rich nuclei close to N=126 were produced by fragmentation of a 1 A GeV 208Pb beam at the FRS at GSI. The beta-decay half-lives of 8 nuclides have been determined. The comparison of the data with model calculations including an approach based on the self-consistent ground-state description and continuum QRPA considering the Gamow-Teller and first-forbidden decays provide a first indication on the importance of first-forbidden transitions around A=195. The measured data indicate that the matter flow in the r-process to heavier fissioning nuclei is faster than previously expected.

T. Kurtukian-Nieto; J. Benlliure; L. Audouin; F. Becker; B. Blank; I. N. Borzov; E. Casarejos; M. Fernandez-Ordonez; J. Giovinazzo; D. Henzlova; B. Jurado; K. Langanke; G. Martinez-Pinedo; J. Pereira; F. Rejmund; K. -H. Schmidt; O. Yordanov

2007-11-01

119

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

120

Neutron Capture in the r-Process -- Do We Know Them And Does It Make Any Difference?  

E-print Network

The r-process involves neutron-rich nuclei far off stability for which no experimental cross sections are known. Therefore, one has to rely on theory which might be prone to considerable uncertainties far off stability. To investigate the impact of such uncertainties, nucleosynthesis in hot bubble models followed completely from high-temperature NSE to low-temperature neutron capture freeze-out were calculated with largely varied rates. Due to the (n,gamma)-(gamma,n) equilibrium established at the onset of the r-process, only late-time neutron captures are important which mainly modify the abundances around the third r-process peak.

T. Rauscher

2004-07-16

121

Mass measurements beyond the major r-process waiting point 80Zn  

E-print Network

High-precision mass measurements on neutron-rich zinc isotopes 71m,72-81Zn have been performed with the Penning trap mass spectrometer ISOLTRAP. For the first time the mass of 81Zn has been experimentally determined. This makes 80Zn 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. As a consequence, 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 farther from stability.

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

2008-11-14

122

Mass measurements beyond the major r-process waiting point 80Zn.  

PubMed

High-precision mass measurements on neutron-rich zinc isotopes (71m,72-81)Zn have been performed with the Penning trap mass spectrometer ISOLTRAP. For the first time, the mass of 81Zn has been experimentally determined. This makes 80Zn 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. PMID:19437636

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

2008-12-31

123

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

E-print Network

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

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

2004-10-19

124

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

125

The Origins of Light and Heavy R-process Elements Identified by Chemical Tagging of Metal-poor Stars  

NASA Astrophysics Data System (ADS)

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

Tsujimoto, Takuji; Shigeyama, Toshikazu

2014-11-01

126

Adams, R. (1993). Radial decomposition of discs and spheres. CVGIP: Graphical Models and Image Processing, 55, 325-332.  

E-print Network

and Image Processing, 55, 325-332. Adams, R. and Bischof, L. (1994). Seeded region growing. IEEE-floe identification in satellite images using mathe- matical morphology and clustering about principal curves. Journal Processing in Medical Imaging. Proceedings of the 13th International Conference on Information Processing

Stone, J. V.

127

The Role of Fission in Neutron Star Mergers and the Position of the Third r-Process Peak  

E-print Network

The comparison between observational abundance features and those obtained from nucleosynthesis predictions of stellar evolution and/or explosion simulations can scrutinize two aspects: (a) the conditions in the astrophysical production site and (b) the quality of the nuclear physics input utilized. Here we test the abundance features of r-process nucleosynthesis calculations for the dynamical ejecta of neutron star merger simulations based on three different nuclear mass models: The Finite Range Droplet Model (FRDM), the (quenched version of the) Extended Thomas Fermi Model with Strutinsky Integral (ETFSI-Q), and the Hartee-Fock-Bogoliubov (HFB) mass model. We make use of corresponding fission barrier heights and compare the impact of four different fission fragment distribution models on the final r-process abundance distribution. Furthermore, we explore the origin of a shift in the third r-process peak position in comparison with the solar r-process abundances which have been noticed in a number of merger ...

Eichler, Marius; Kelic, Alexandra; Korobkin, Oleg; Langanke, Karlheinz; Martinez-Pinedo, Gabriel; Panov, Igor V; Rauscher, Thomas; Rosswog, Stephan; Winteler, Christian; Zinner, Nikolaj T; Thielemann, Friedrich-Karl

2014-01-01

128

Functional analysis of Rrp7p, an essential yeast protein involved in pre-rRNA processing and ribosome assembly.  

PubMed

During the functional analysis of open reading frames (ORFs) identified during the sequencing of chromosome III of Saccharomyces cerevisiae, the previously uncharacterized ORF YCL031C (now designated RRP7) was deleted. RRP7 is essential for cell viability, and a conditional null allele was therefore constructed, by placing its expression under the control of a regulated GAL promoter. Genetic depletion of Rrp7p inhibited the pre-rRNA processing steps that lead to the production of the 20S pre-rRNA, resulting in reduced synthesis of the 18S rRNA and a reduced ratio of 40S to 60S ribosomal subunits. A screen for multicopy suppressors of the lethality of the GAL::rrp7 allele isolated the two genes encoding a previously unidentified ribosomal protein (r-protein) that is highly homologous to the rat r-protein S27. When present in multiple copies, either gene can suppress the lethality of an RRP7 deletion mutation and can partially restore the ribosomal subunit ratio in Rrp7p-depleted cells. Deletion of both r-protein genes is lethal; deletion of either single gene has an effect on pre-rRNA processing similar to that of Rrp7p depletion. We believe that Rrp7p is required for correct assembly of rpS27 into the preribosomal particle, with the inhibition of pre-rRNA processing appearing as a consequence of this defect. PMID:9271380

Baudin-Baillieu, A; Tollervey, D; Cullin, C; Lacroute, F

1997-09-01

129

Constraint on the cosmic age from the solar $r$-process abundances  

E-print Network

The cosmic age is an important physical quantity in cosmology. Based on the radiometric method, a reliable lower limit of the cosmic age is derived to be $15.68\\pm 1.95$ Gyr by using the $r$-process abundances inferred for the solar system and observations in metal-poor stars. This value is larger than the latest cosmic age $13.813\\pm 0.058$ Gyr from Planck 2013 results, while they still agree with each other within the uncertainties. The uncertainty of $1.95$ Gyr mainly originates from the error on thorium abundance observed in metal-poor star CS 22892-052, so future high-precision abundance observations on CS 22892-052 are needed to understand this age deviation.

Heng, T H; Niu, Z M; Sun, B H; Guo, J Y

2014-01-01

130

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

131

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

E-print Network

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

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

2012-03-20

132

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

PubMed

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

Federsel, Hans-Jürgen

2006-11-01

133

Temporary Repair of Corneal Perforation Using Tutoplast((R))-Processed Pericardium Graft.  

PubMed

A 30-year-old woman with a history of long-standing poor vision since her previous left ocular trauma in her early childhood presented with traumatic corneal perforation in her left eye. She underwent three amniotic membrane grafts along with tissue glue application, which failed to halt the progressive corneal thinning and recurrent perforation. Penetrating keratoplasty (PKP) was planned. However, a donor cornea was not immediately available for transplantation. Therefore, a Tutoplast((R))-processed pericardium graft was placed over the edges of the corneal lesion for a temporary tectonic purpose. Three days later, PKP was performed. A pericardium graft is an effective alternative method to maintain the structural integrity of the cornea while waiting for the arrival of a donor cornea for keratoplasty in the case of severe corneal perforation. PMID:20337270

Yoo, Chungkwon; Kang, Su Y; Eom, Young S; Kim, Hyo-Myung

2010-03-01

134

Structures of exotic 131,133Sn isotopes and effect on r-process nucleosynthesis  

NASA Astrophysics Data System (ADS)

Background: Four strong single-particle bound levels with strikingly similar level spacings have recently been measured in 131Sn and 133Sn. This similarity has 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, is also needed to determine neutron capture cross sections—and corresponding capture reaction rates—on 130,132Sn. The 130Sn(n,?) rate was shown in a recent sensitivity study to significantly impact the synthesis of heavy elements in the r-process in supernovae.Purpose: Understand the structure of bound and resonant levels in 131,133Sn, and determine if the densities of unbound resonant levels are sufficiently high to warrant statistical model treatments of neutron capture on 130,132Sn.Method: Single-particle bound and resonant levels for 131,133Sn are self-consistently calculated by the analytical continuation of the coupling constant (ACCC) method based on a relativistic mean field (RMF) theory with BCS approximation.Results: We obtain four strong single-particle bound levels in both 131,133Sn with an ordering that agrees with experiments and spacings that, while differing from experiment, are consistent between the Sn isotopes. We also find at most one single-particle level in the effective energy range for neutron captures in the r-process.Conclusions: Our RMF+ACCC+BCS model successfully reproduces observed single-particle bound levels in 131,133Sn and self-consistently predicts single-particle resonant levels with densities too low for widely used traditional statistical model treatments of neutron capture cross sections on 130,132Sn employing Fermi gas level density formulations.

Zhang, Shi-Sheng; Smith, M. S.; Arbanas, G.; Kozub, R. L.

2012-09-01

135

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

NASA Astrophysics Data System (ADS)

Aims: We study the abundance distributions of a sample of metal-rich barium stars provided by Pereira et al. (2011, A&A, 533, A51) to investigate the s- and r-process nucleosynthesis in the metal-rich environment. Methods: We compared the theoretical results predicted by a parametric model with the observed abundances of the metal-rich barium stars. Results: We found that six barium stars have a significant r-process characteristic, and we divided the barium stars into two groups: r-rich barium stars (Cr > 5.0, [La/Nd] < 0) and normal barium stars. The behavior of the r-rich barium stars seems more like that of the metal-poor r-rich and CEMP-r/s stars. We suggest that the most possible formation mechanism for these stars is the s-process pollution, although their abundance patterns can be fitted very well when the pre-enrichment hypothesis is included. That we cannot explain them well using the s-process nucleosynthesis alone may be due to our incomplete knowledge on the production of Nd, Eu, and other relevant elements by the s-process in metal-rich and super metal-rich environments (see details in Pereira et al. 2011).

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

2014-06-01

136

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

PubMed Central

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.

2013-01-01

137

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

2013-08-01

138

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

E-print Network

other multimedia systems for both entertainment and more serious applications. Two fairly recent independent developments in this field are R-functions and the curvelet transform. R-functions were developed to make it possible to represent complex...

Wisinger, John L.

2012-06-07

139

Chapter for R. Rama (Ed.), Innovation in the food and drink processing industry, Haworth Press Inc, N.Y.  

E-print Network

Inc, N.Y. Biotech Innovation in Europe's Food and Drink Processing Industry: Promise, Barriers1 Chapter for R. Rama (Ed.), Innovation in the food and drink processing industry, Haworth Press of biotechnology to contribute to "the production of food with improved quality and nutritional content" (ACOST

Paris-Sud XI, Université de

140

COPASutils: An R Package for Reading, Processing, and Visualizing Data from COPAS Large-Particle Flow Cytometers  

PubMed Central

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

Shimko, Tyler C.; Andersen, Erik C.

2014-01-01

141

Extracellular identification of a processed type II ComR/ComS pheromone of Streptococcus mutans.  

PubMed

The competence-stimulating peptide (CSP) and the sigX-inducing peptide (XIP) are known to induce Streptococcus mutans competence for genetic transformation. For both pheromones, direct identification of the native peptides has not been accomplished. The fact that extracellular XIP activity was recently observed in a chemically defined medium devoid of peptides, as mentioned in an accompanying paper (K. Desai, L. Mashburn-Warren, M. J. Federle, and D. A. Morrison, J. Bacteriol. 194:3774-3780, 2012), provided ideal conditions for native XIP identification. To search for the XIP identity, culture supernatants were filtered to select for peptides of less than 3 kDa, followed by C(18) extraction. One peptide, not detected in the supernatant of a comS deletion mutant, was identified by tandem mass spectrometry (MS/MS) fragmentation as identical to the ComS C-terminal sequence GLDWWSL. ComS processing did not require Eep, a peptidase involved in processing or import of bacterial small hydrophobic peptides, since eep deletion had no inhibitory effect on XIP production or on synthetic XIP response. We investigated whether extracellular CSP was also produced. A reporter assay for CSP activity detection, as well as MS analysis of supernatants, revealed that CSP was not present at detectable levels. In addition, a mutant with deletion of the CSP-encoding gene comC produced endogenous XIP levels similar to those of a nondeletion mutant. The results indicate that XIP pheromone production is a natural phenomenon that may occur in the absence of natural CSP pheromone activity and that the heptapeptide GLDWWSL is an extracellular processed form of ComS, possibly the active XIP pheromone. This is the first report of direct identification of a ComR/ComS pheromone. PMID:22609914

Khan, Rabia; Rukke, Håkon V; Ricomini Filho, Antonio Pedro; Fimland, Gunnar; Arntzen, Magnus Ø; Thiede, Bernd; Petersen, Fernanda C

2012-08-01

142

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

143

AN r-PROCESS KILONOVA ASSOCIATED WITH THE SHORT-HARD GRB 130603B  

SciTech Connect

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 {sup k}ilonova{sup )}. The early afterglow fades rapidly with {alpha} {approx}< -2.6 at t Almost-Equal-To 8-32 hr post-burst and has a spectral index of {beta} Almost-Equal-To -1.5 (F{sub {nu}}{proportional_to}t {sup {alpha}}{nu}{sup {beta}}), leading to an expected near-IR brightness at the time of the first HST observation of m{sub F160W}(t = 9.4 days) {approx}> 29.3 AB mag. Instead, the detected source has m{sub F160W} = 25.8 {+-} 0.2 AB mag, corresponding to a rest-frame absolute magnitude of M{sub J} Almost-Equal-To -15.2 mag. The upper limit in the HST optical observations is m{sub F606W} {approx}> 27.7 AB mag (3{sigma}), indicating an unusually red color of V - H {approx}> 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{sub ej} Almost-Equal-To 0.03-0.08 M{sub Sun} for v{sub ej} Almost-Equal-To 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. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2013-09-10

144

Analysis of nucleolar transcription and processing domains and pre-rRNA movements by in situ hybridization  

Microsoft Academic Search

We have examined the cytological localization of rRNA synthesis, transport, and processing events within the mammalian cell\\u000a nucleolus by double-label fluorescent in situ hybridization analysis using probes for small selected segments of pre-rRNA,\\u000a which have known half-lives. In particular, a probe for an extremely short-lived 5? region that is not found separate of the\\u000a pre-rRNA identifies nascent transcripts within the

Inara B. Lazdins; Michael Delannoy; Barbara Sollner-Webb

1997-01-01

145

Nuclear RNase MRP is required for correct processing of pre-5.8S rRNA in Saccharomyces cerevisiae.  

PubMed Central

RNase MRP is a site-specific ribonucleoprotein endoribonuclease that cleaves RNA from the mitochondrial origin of replication in a manner consistent with a role in priming leading-strand DNA synthesis. Despite the fact that the only known RNA substrate for this enzyme is complementary to mitochondrial DNA, the majority of the RNase MRP activity in a cell is found in the nucleus. The recent characterization of this activity in Saccharomyces cerevisiae and subsequent cloning of the gene coding for the RNA subunit of the yeast enzyme have enabled a genetic approach to the identification of a nuclear role for this ribonuclease. Since the gene for the RNA component of RNase MRP, NME1, is essential in yeast cells and RNase MRP in mammalian cells appears to be localized to nucleoli within the nucleus, we utilized both regulated expression and temperature-conditional mutations of NME1 to assay for a possible effect on rRNA processing. Depletion of the RNA component of the enzyme was accomplished by using the glucose-repressed GAL1 promoter. Shortly after the shift to glucose, the RNA component of the enzyme was found to be depleted severely, and rRNA processing was found to be normal at all sites except the B1 processing site. The B1 site, at the 5' end of the mature 5.8S rRNA, is actually composed of two cleavage sites 7 nucleotides apart. This cleavage normally generates two species of 5.8S rRNA at a ratio of 10:1 (small to large) in most eukaryotes. After RNase MRP depletion, yeast cells were found to have almost exclusively the larger species of 5.8S rRNA. In addition, an aberrant 309-nucleotide precursor that stretched from the A2 to E processing sites of rRNA accumulated in these cells. Temperature-conditional mutations in the RNase MRP RNA gene gave an identical phenotype.Translation in yeast cells depleted of the smaller 5.8S rRNA was found to remain robust, suggesting a possible function for two 5.8S rRNAs in the regulated translation of select messages. These results are consistent with RNase MRP playing a role in a late step of rRNA processing. The data also indicate a requirement for having the smaller form of 5.8S rRNA, and they argue for processing at the B1 position being composed of two separate cleavage events catalyzed by two different activities. Images PMID:8247008

Schmitt, M E; Clayton, D A

1993-01-01

146

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

147

Constraint on the cosmic age from the solar r-process abundances  

NASA Astrophysics Data System (ADS)

The cosmic age is an important physical quantity in cosmology. Based on the radiometric method, a reliable lower limit of the cosmic age is derived to be 15.68+/- 1.94 Gyr, using the r-process abundances inferred for the solar system and observations in metal-poor stars. If the central value is taken, this value is larger than the latest cosmic age 13.813+/- 0.058 Gyr determined from Planck 2013 results; however, the two agree with each other within uncertainties. The uncertainty of 1.94 Gyr mainly originates from the error on thorium abundance observed in metal-poor star CS 22892-052, so future high-precision abundance observations on CS 22892-052 are valuable to further check the cosmic age determined from different independent methods. On the other hand, by taking the cosmic age from Planck 2013 results as a standard value, the lower limit of abundance ratios Th/X and U/X in metal-poor stars is deduced as a guidance to future observations.

Heng, T. H.; Xu, X. D.; Niu, Z. M.; Sun, B. H.; Guo, J. Y.

2014-10-01

148

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

149

?-, r-, and s-process element trends in the Galactic thin and thick disks  

NASA Astrophysics Data System (ADS)

From a detailed elemental abundance analysis of 102 F and G dwarf stars we present abundance trends in the Galactic thin and thick disks for 14 elements (O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, Y, Ba, and Eu). Stellar parameters and elemental abundances (except for Y, Ba and Eu) for 66 of the 102 stars were presented in our previous studies (Bensby et al. [CITE], A&A, 410, 527, [CITE], A&A, 415, 155). The 36 stars that are new in this study extend and confirm our previous results and allow us to draw further conclusions regarding abundance trends. The s-process elements Y and Ba, and the r-element Eu have also been considered here for the whole sample for the first time. With this new larger sample we now have the following results: 1) smooth and distinct abundance trends that for the thin and thick disks are clearly separated; 2) the ?-element trends for the thick disk show typical signatures from the enrichment of SN Ia; 3) the thick disk stellar sample is in the mean older than the thin disk stellar sample; 4) the thick disk abundance trends are invariant with galactocentric radii (R_m); 5) the thick disk abundance trends appear to be invariant with vertical distance (Z_max) from the Galactic plane. Adding further evidence from the literaure we argue that a merger/interacting scenario with a companion galaxy to produce a kinematical heating of the stars (that make up today's thick disk) in a pre-existing old thin disk is the most likely formation scenario for the Galactic thick disk. The 102 stars have -1 ? [Fe/H] ? +0.4 and are all in the solar neighbourhood. Based on their kinematics they have been divided into a thin disk sample and a thick disk sample consisting of 60 and 38 stars, respectively. The remaining 4 stars have kinematics that make them kinematically intermediate to the two disks. Their chemical abundances also place them in between the two disks. Which of the two disk populations these 4 stars belong to, or if they form a distinct population of their own, can at the moment not be settled. The 66 stars from our previous studies were observed with the FEROS spectrograph on the ESO 1.5-m telescope and the CES spectrograph on the ESO 3.6-m telescope. Of the 36 new stars presented here 30 were observed with the SOFIN spectrograph on the Nordic Optical Telescope on La Palma, 3 with the UVES spectrograph on VLT/UT2, and 3 with the FEROS spectrograph on the ESO 1.5-m telescope. All spectra have high signal-to-noise ratios (typically S/N? 250) and high resolution (R˜ 80 000, 45 000, and 110 000 for the SOFIN, FEROS, and UVES spectra, respectively). Based on observations collected at the Nordic Optical Telescope on La Palma, Spain, and at the European Southern Observatories on La Silla and Paranal, Chile, Proposals # 65.L-0019(B), 67.B-0108(B), 69.B-0277. Full Tables [see full text], [see full text] and [see full text] are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/433/185

Bensby, T.; Feltzing, S.; Lundström, I.; Ilyin, I.

2005-04-01

150

R&D-MARKETING INTEGRATION IN THE NEW PRODUCT DEVELOPMENT PROCESS  

Microsoft Academic Search

The requirement of quick accommodation to dynamic changes strengthens the role of knowledge flow in interfunctional relations. The requirement of integrated knowledge is the most explicit in the relations of R+D and marketing, researchers are increasingly aware of its key role in innovation. The integration of R+D and marketing - the interface problem - is a decisive field in current

Ildikó PETRUSKA

2004-01-01

151

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

ERIC Educational Resources Information Center

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

Sanders, Owen

152

Discovery of HE 1523-0901, a Strongly r-Process Enhanced Metal-Poor Star with Detected Uranium  

E-print Network

We present age estimates for the newly discovered very r-process enhanced metal-poor star HE 1523-0901 ([Fe/H]=-2.95) based on the radioactive decay of Th and U. The bright (V=11.1) giant was found amongst a sample of bright metal-poor stars selected from the Hamburg/ESO survey. From an abundance analysis of a high-resolution (R=75,000) VLT/UVES spectrum we find HE 1523-0901 to be strongly overabundant in r-process elements ([r/Fe]=1.8). The abundances of heavy neutron-capture elements (Z>56) measured in HE 1523-0901 match the scaled solar r-process pattern extremely well. We detect the strongest optical U line at 3859.57 A. For the first time, we are able to employ several different chronometers, such as the U/Th, U/Ir, Th/Eu and Th/Os ratios to measure the age of a star. The weighted average age of HE 1523-0901 is 13.2 Gyr. Several sources of uncertainties are assessed in detail.

Anna Frebel; Norbert Christlieb; John E. Norris; Christopher Thom; Timothy C. Beers; Jaehyon Rhee

2007-03-15

153

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

E-print Network

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

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

2008-02-04

154

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.

155

R-chondrite bulk-chemical compositions and diverse oxides: Implications for parent-body processes  

NASA Astrophysics Data System (ADS)

R chondrites are among the most oxidized chondrite groups; they also have the highest ?17O values known in whole-rock meteorites. We analyzed R chondrites (six Antarctic, four hot-desert) by instrumental neutron activation analysis. Data for one of the former and three of the latter show large weathering effects, but the remainder show only moderate scatter and permit us to determine trends and mean compositions for the group. Bulk R-chondrite compositions are similar to those in H and L chondrites, but the concentrations of several volatiles, especially Se and Zn, are higher; the more volatile the element, the higher the enrichment in R chondrites relative to H and L. Petrologic types in R chondrites extend as low as 3.6. We determined olivine compositional distributions and studied opaque oxides in 15 R-chondrite thin sections, including a newly discovered R4 clast in Bencubbin (adding to the diversity of chondritic clasts in this polymict breccia) and an R clast in CM2 Murchison. Opaque oxides in R chondrites include nearly pure magnetite, Al-rich chromite, magnetite-chromite solid solution, nearly pure chromite, and ilmenite. This diverse set of opaque phases reflects differing aqueous-alteration conditions. The least equilibrated R chondrites contain nearly pure magnetite but the spinels in metamorphosed R chondrites contain additional components (e.g., Cr2O3 and Al2O3 and some minor cations). The NiO content in olivine correlates with the magnetite component in magnetite-chromite solid solution in equilibrated R chondrites and is a function of the degree of oxidation. The absence of metallic Fe in A-881988 and LAP 031156 indicates a high degree of oxidation; the relatively low-FeO (Fa35) olivine in these rocks in part reflects the conversion of Fe2+ to Fe3+ and its partitioning into magnetite. Oxidation trends in R chondrites are affected by both aqueous alteration and thermal metamorphism. The differing degrees of oxidation in this group reflect differences in local environments on the parent asteroid.

Isa, Junko; Rubin, Alan E.; Wasson, John T.

2014-01-01

156

? 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

157

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

SciTech Connect

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

Surman, Rebecca [Union College; Beun, Joshua [North Carolina State University; Mclaughlin, Gail C [North Carolina State University; Hix, William Raphael [ORNL

2009-01-01

158

Neutron capture rates near A=130 that effect a global change to the r-process abundance distribution  

SciTech Connect

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

Surman, R.; Beun, J.; McLaughlin, G. C.; Hix, W. R. [Department of Physics, Union College, Schenectady, New York 12308 (United States); Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202 (United States); Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6374 (United States)

2009-04-15

159

30 ENGINEERING & SCIENCE WI NTE R 2012 Whether processing radar signals in Norway or assessing rock properties in Nigeria, Calte  

E-print Network

of genetic engineering in Ireland; he helped establish the Smurfit Institute of Genetics in 1998, where he30 ENGINEERING & SCIENCE WI NTE R 2012 Whether processing radar signals in Norway or assessing rock, England, Sarah Ferguson, BS '08, Engineering & Applied Science (CNS) Sarah Ferguson is a trader at Ronin

160

The New Digital Engineering Design and Graphics Process R E. Barr, T. J. Krueger, and T. A. Aanstoos  

E-print Network

The New Digital Engineering Design and Graphics Process R E. Barr, T. J. Krueger, and T. A for the educational setting. I. INTRODUCTION The discipline of Engineering Design Graphics has been a cornerstone to solve graphical problems. The field has gone from using drafting boards, to computer-aided design

Ben-Yakar, Adela

161

Recent advances in R and D of commercial catalysts for acrylonitrile synthesis, styrene production and toluene disproportionation processes  

Microsoft Academic Search

This paper reports the progresses in R and D and commercial application of the industrial catalysts, developed and produced by SRIPT for acrylonitrile, styrene and toluene disproportionation processes.The research works of developing a unique method of catalyst preparation, adding proper amount of sodium ions to the Mo–Bi oxides system to improve catalytic activity and attrition resistance, and adding bromine ions

Qingling Chen; Xin Chen; Liansheng Mao; Wencai Cheng

1999-01-01

162

New Nuclear Reaction Flow during r-Process Nucleosynthesis in Supernovae: Critical Role of Light Neutron-Rich Nuclei  

E-print Network

We study the role of light neutron-rich nuclei during r-process nucleosynthesis in supernovae. Most previous studies of the r-process have concentrated on the reaction flow of heavy unstable nuclei. Although the nuclear reaction network includes a few thousand heavy nuclei, only limited reaction flow through light-mass nuclei near the stability line has been used in those studies. However, in a viable scenario of the r-process in neutrino-driven winds, the initial condition is a high-entropy hot plasma consisting of neutrons, protons, and electron-positron pairs experiencing an intense flux of neutrinos. In such environments light-mass nuclei as well as heavy nuclei are expected to play important roles in the production of seed nuclei and r-process elements. Thus, we have extended our fully implicit nuclear reaction network so that it includes all nuclei up to the neutron drip line for Z $ \\leq 10$, in addition to a larger network for Z $ \\geq 10$. In the present nucleosynthesis study, we utilize a wind model of massive SNeII explosions to study the effects of this extended network. We find that a new nuclear-reaction flow path opens in the very light neutron-rich region. This new nuclear reaction flow can change the final heavy-element abundances by as much as an order of magnitude.

M. Terasawa; K. Sumiyoshi; T. Kajino; G. J. Mathews; I. Tanihata

2001-07-19

163

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

2013-03-13

164

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

PubMed

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

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

2014-06-01

165

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

166

s-Process in Low Metallicity Stars: CEMP-s and CEMP-s+r  

NASA Astrophysics Data System (ADS)

A sample of 74 very metal-poor, C- and s-rich rich stars were collected from the literature. We give here a summary of the results obtained by comparing spectroscopic abundances of CEMP-s stars and AGB theoretical models, using different 13C-pocket efficiencies, initial masses and initial r-enrichments. They acquired the C and s enrichments by mass transfer in a close binary system from the more massive companion while on the AGB (now a white dwarf). In general, reasonable solutions are obtained for all the stars. About half of these objects have a relevant number of elements detected at high resolution spectroscopy, while only 10 of them were obtained at moderate resolution. When few elements were detected, several solutions are possible. For most of the main-sequence turnoff stars, due to the low Na and, in some cases, the low ls peak (Sr-Y-Zr), a good interpretation can only be obtained with lower initial AGB masses (MiniAGB<=1.4 Msolar), and the absence of dilution factors suggests that no efficient thermohaline mixing had occurred. Among the stars with r-elements measured, an important number is r-enhanced (~46%), including six objects which need a strong initial r-enrichment ([r/Fe]ini = 2.0 dex). We show here some examples.

Bisterzo, S.; Gallino, R.

2008-04-01

167

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

168

A Study of Processing Parameters on the Carburization of C2R Steels  

Microsoft Academic Search

This study reports an investigation of the effect of carburizing variables - temperature, time and percentage of energizer -on the case properties of C2R steel obtained from HMT Ltd. India. A carburizer consisting of hardwood charcoal and coke respectively in the ratio of 2:1 was used for the research with sodium carbonate as the energizer. The carburizing box was filled

P. O. Atanda; O. E. Olorunniwo; L. E. Umoru; A. D. Adeyeye

169

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

E-print Network

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

Dinah M. Allen; Beatriz Barbuy

2006-04-04

170

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

EPA Science Inventory

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

171

Age Differences in Word and Language Processing Ph. Allen and Th.R. Bashore (Editors)  

E-print Network

on changes in language processing over the next forty to fifty years. Notable exceptions Elsevier Science B.V. All rights reserved. Do the waves begin to waver? ERP studies of language processing as an adjunct to the study of aphasia. While language processes have usually been thought to be fairly

Kutas, Marta

172

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

SciTech Connect

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

Sumikama, T.; Yoshinaga, K. [Department of Physics, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Watanabe, H. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); and others

2012-11-12

173

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

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

174

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

SciTech Connect

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

Saeki, Takayuki [KEK; Funahashi, Y. [KEK; Hayano, H. [KEK; Kato, Seigo [KEK; Nishiwaki, Michiru [KEK; Sawabe, Motoaki [KEK; Ueno, Kenji [KEK; Watanabe, K. [KEK; Antoine, Claire [CEA, Gif-sur-Yvette; Berry, Stefurn [CEA, Gif-sur-Yvette; Eozenou, F. [CEA, Gif-sur-Yvette; Gasser, Y. [CEA, Gif-sur-Yvette; Visentin, B. [CEA, Gif-sur-Yvette; Clemens, William A. [JLAB; Geng, Rongli [JLAB; Manus, Robert [JLAB; Tyagi, Puneet [GUAS/AS, Ibaraki

2009-11-01

175

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

PubMed

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

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

2014-01-01

176

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

177

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

SciTech Connect

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

Roederer, Ian U.; Sneden, Christopher [Department of Astronomy, University of Texas at Austin, 1 University Station, C1400 Austin, TX 78712-0259 (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)], E-mail: iur@astro.as.utexas.edu

2010-05-01

178

GPS-R L1 interference signal processing for soil moisture estimation: an experimental study  

NASA Astrophysics Data System (ADS)

Global positioning system reflectometry (GPS-R) is an emerging area of GPS applications in microwave remote sensing using multipath reflected signals. Soil moisture estimation is one of the many potential applications of the GPS-R technique. The focus of this study is on investigating the feasibility of soil moisture estimation based on GPS L1 band interference signals which can be readily captured using a low-cost off-the-shelf L1-band GPS receiver. The theoretical background is studied, and the field experiments conducted are described. Power spectrum analysis is performed on the received interference signals to determine the interference signal frequency variation, and cosine similarity is applied to identify the initial phase change. Data collected at a number of continuously operating GPS stations are also analyzed. The results demonstrate that both interference signal frequency and phase have changed significantly after rainfalls occurred. That is, it is possible to estimate soil moisture by analyzing the frequency change and phase shift. However, it is also observed that the phase shift is inconsistent in some cases. Ongoing work will focus on figuring out the source of the inconsistency so that reliable estimation of soil moisture can be achieved.

Yan, Songhua; Li, Zhengyong; Yu, Kegen; Zhang, Kefei

2014-12-01

179

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

180

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

181

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

NASA Technical Reports Server (NTRS)

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

Guiltinan, J.

1976-01-01

182

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

PubMed

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

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

2014-12-01

183

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

PubMed Central

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

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

2014-01-01

184

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

185

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

186

Pri-miR-17-92a transcript folds into a tertiary structure and autoregulates its processing  

PubMed Central

MicroRNAs control gene expression either by RNA transcript degradation or translational repression. Expressions of miRNAs are highly regulated in tissues, disruption of which leads to disease. How this regulation is achieved and maintained is still largely unknown. MiRNAs that reside on clustered or polycistronic transcripts represent a more complex case where individual miRNAs from a cluster are processed with different efficiencies despite being cotranscribed. To shed light on the regulatory mechanisms that might be operating in these cases, we considered the long polycistronic primary miRNA transcript pri-miR-17-92a that contains six miRNAs with diverse functions. The six miRNA domains on this cluster are differentially processed to produce varying amounts of resultant mature miRNAs in different tissues. How this is achieved is not known. We show, using various biochemical and biophysical methods coupled with mutational studies, that pri-miR-17-92a adopts a specific three-dimensional architecture that poses a kinetic barrier to its own processing. This tertiary structure could create suboptimal protein recognition sites on the pri-miRNA cluster due to higher-order structure formation. PMID:22450760

Chakraborty, Saikat; Mehtab, Shabana; Patwardhan, Anand; Krishnan, Yamuna

2012-01-01

187

R&D for long tapes with high I c by advanced TFA-MOD process  

Microsoft Academic Search

Recent progress in the research and development of the TFA-MOD processing for the coated conductors was reviewed. For the higher Ic performance, crack generation in the thick films was a problem, which limits increasing Ic values. It was found that both lower heating rate and low PH2O in the crystallization step are effective to improve the critical thickness for obtaining

Teruo Izumi; Hiroshi Fuji; Yuji Aoki; Ryo Teranishi; Junko Matsuda; Koichi Nakaoka; Yutaka Kitoh; Sukeharu Nomoto; Yutaka Yamada; Akimasa Yajima; Takashi Saitoh; Yuh Shiohara

2006-01-01

188

The Relationship between WAIS-R Abilities and Speed of Processing in a Word Identification Task.  

ERIC Educational Resources Information Center

Results from a representative sample of 123 adults in the United Kingdom tested with the Wechsler Adult Intelligence Scale-Revised and a test of word identification time are in line with previous findings that speed of information processing is significantly related to performance IQ but not to verbal IQ. (SLD)

McGeorge, P.; And Others

1996-01-01

189

Categories and Underlying Processes, or Representative Behavior Samples and S-R Analysis: Opposing Strategies.  

ERIC Educational Resources Information Center

Psychological researchers should deal with the concrete stimulus-response principles of learning on which behavior is based, and study behaviors that are representative of real life behaviors. The present research strategy has come from two faulty ideas: first, a concern with underlying, inferred mental processes, rather than with actual tasks or…

Staats, Arthur W.

190

Eurographics Symposium on Geometry Processing (2004) R. Scopigno, D. Zorin, (Editors)  

E-print Network

become pop- ular for geometric modeling because the subdivision process places no restriction, the image being de- formed is a cross-section of a mouse brain where the pixel intensities represent the cell density in different anatomi- cal (colored) regions of the brain. On the left, the image has been

Warren, Joe

191

1095 REAL-TIME PROCESSING OF DOWNLINK PHASE MEASUREMENTS * Larry R. D'Addario  

E-print Network

The two-way time transfer link between earth station and satellite will be * *of the form shown in Figure. Fig. 1: Conceptual block diagram of the two-way time transfer. The present memo is concerned 1095 REAL-TIME PROCESSING OF DOWNLINK PHASE MEASUREMENTS

Groppi, Christopher

192

Software Project Improvement through Personal Software Process in a R&D Center  

Microsoft Academic Search

Any software engineer with a working experience greater than a few months knows about the problems that projects face to reach the planned goals, on-time and on-budget, and that when they are not cancelled. When thinking about software process improvement, several methodologies can be found on the literature. In this paper, we will talk about how to employ these tools

Iñaki Etxaniz

2007-01-01

193

R&D project selection using ANP...the analytic network process  

Microsoft Academic Search

This article discusses using the analytic network process (ANP) for decision-making. ANP allows qualitative values to be transformed into quantitative values for comparative analysis. The ANP is a relatively simple, intuitive approach that managers and other decision-makers can accept

Laura M. Meade; Adrien Presley

2002-01-01

194

The Influence Of Neutron Capture Rates On The Rare Earth Region Of The r-Process Abundance Pattern  

E-print Network

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.

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

2012-04-02

195

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

NASA Astrophysics Data System (ADS)

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

Hosmer, Paul Thomas

196

The neutron long counter NERO for studies of beta-delayed neutron emission in the r-process  

E-print Network

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

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

2010-07-28

197

Nuclear Shell Effects near the r-Process Path at N=82 in the Relativistic Hartree-Bogoliubov Theory  

E-print Network

Evolution of the shell structure of nuclei near the neutron drip line is investigated in the Relativistic Hartree-Bogoliubov (RHB) theory. By introducing the vector self-coupling of $\\omega$ meson in the RHB theory, we reproduce successfully the experimental data on the shell effects about the waiting-point nucleus $^{80}$Zn. With this basis, it is shown that the shell effects at N=82 in the inaccessible region of the r-process path remain strong. In contrast, a quenching exhibited by the HFB+SkP approach is shown to be incompatible with the available data. Consequently, the neutrino-driven mechanism of the nucleosynthesis is supported.

M. M. Sharma; A. R. Farhan

2000-06-21

198

Breit-Pauli R-Matrix Calculations for L-Shell Atomic Processes in fe XVI, fe XVII, and XVIII  

NASA Astrophysics Data System (ADS)

We report extensive relativistic close coupling R-matrix calculations of L-shell atomic processes in Fe XVI, Fe XVII, and Fe XVIII. In particular these include photoionization, recombination, transition probabilities, and electron impact excitation of Ne-like Fe XVII. The collisional calculations employ employ the Breit-Pauli R-matrix method and a 89-level eigenfunction expansion including up to n = 4 levels of Fe XVII. Significant resonance enhancement of the collision strengths of forbidden and intercombination is demonstrated. The present results differ from all previous calculations, heretofore without detailed resonance structures, and should help resolve longstanding discrepancies. In particular, the present line ratios of three benchmark diagnostic lines 3C, 3D, and 3E at 15.014, 15.265, and 15.456 Årespectively, are in excellent agreement with two independent measurements on Electron-Beam-Ion-Traps [Laming et al., Astrophys. J 545, L161 (2000) and Brown et al., Astrophys. J 502, 1015 (1998)]. The strong energy dependence due to resonances in these and other cross sections is demonstrated. The new theoretical results should be of considerable interest in uc(x-ray) plasma diagnostics of laboratory and astrophysical sources. Relativistic R-matrix calculations for photoionization and recombination of Fe XVI and Fe XVII are in progress. Partial support from the NSF and NASA is acknowledged.

Chen, Guo Xin; Nahar, Sultana; Pradhan, Anil; Zhang, Honglin

2002-05-01

199

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

SciTech Connect

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

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

1989-12-01

200

Genetic identification of Arabidopsis RID2 as an essential factor involved in pre-rRNA processing.  

PubMed

A temperature-sensitive mutant of Arabidopsis, root initiation defective 2-1 (rid2-1), is characterized by peculiar defects in callus formation. To gain insights into the requirements for the reactivation of cell division, we analyzed this mutant and isolated the gene responsible, RID2. The phenotypes of rid2-1 in tissue culture and in seedlings indicated that the rid2 mutation has various (acute and non-acute) inhibitory effects on different aspects of cell proliferation. This suggests that the RID2 function is not directly involved in every cycle of cell division, but is related to 'vitality', supporting cell proliferation. The rid2-1 mutation was shown to cause nucleolar vacuolation and excessive accumulation of various intermediates of pre-rRNA processing. Positional cloning of the RID2 gene revealed that it encodes an evolutionarily conserved methyltransferase-like protein, which was found to localize in the nucleus, with accumulation being most evident in the nucleolus. It can be inferred from these findings that RID2 contributes to the nucleolar activity for pre-rRNA processing, probably through some methylation reaction. PMID:21401745

Ohbayashi, Iwai; Konishi, Mineko; Ebine, Kazuo; Sugiyama, Munetaka

2011-07-01

201

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

E-print Network

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

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

2010-01-01

202

The nuclear shell effects near the r-process path in the relativistic Hartree-Bogoliubov theory  

E-print Network

We have investigated the evolution of the shell structure of nuclei in going from the r-process path to the neutron drip line within the framework of the Relativistic Hartree-Bogoliubov (RHB) theory. By introducing the quartic self-coupling of $\\omega$ meson in the RHB theory in addition to the non-linear scalar coupling of $\\sigma$ meson, we reproduce the available data on the shell effects about the waiting-point nucleus $^{80}$Zn. With this approach, it is shown that the shell effects at N=82 in the inaccessible region of the r-process path become milder as compared to the Lagrangian with the scalar self-coupling only. However, the shell effects remain stronger as compared to the quenching exhibited by the HFB+SkP approach. It is also shown that in reaching out to the extreme point at the neutron drip line, a terminal situation arises where the shell structure at the magic number is washed out significantly.

M. M. Sharma; A. R. Farhan

2002-02-09

203

Process Flexibility: a Survey of Contemporary M.H. Schonenberg, R.S. Mans, N.C. Russell, N.A. Mulyar  

E-print Network

Process Flexibility: a Survey of Contemporary Approaches M.H. Schonenberg, R.S. Mans, N.C. Russell Eindhoven, The Netherlands {m.h.schonenberg,r.s.mans,n.c.russell,nmulyar,w.m.p.v.d.aalst}@tue.nl Abstract

van der Aalst, Wil

204

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

205

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

SciTech Connect

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. [Astrophysical Advances, 607 Marion Place, Palo Alto, CA 94301 (United States)

2013-05-01

206

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

207

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

SciTech Connect

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

Cunningham, D.W.

2002-10-01

208

The r Process in the region of transuranium elements and the contribution of fission products to the nucleosynthesis of nuclei with A ? 130  

Microsoft Academic Search

We discuss the influence of nuclear masses and mass distributions of fission products on the formation of heavy elements at\\u000a the final stages of the r-process recycled through fission on long duration timescales. The fission recycling is of great importance in an environment\\u000a with a high density of free neutrons (e.g., in neutron star merger scenarios), when the r-process duration

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

2008-01-01

209

The Hamburg/ESO R-process enhanced star survey (HERES). II. Spectroscopic analysis of the survey sample  

NASA Astrophysics Data System (ADS)

We present the results of analysis of "snapshot" spectra of 253 metal-poor halo stars -3.8? [Fe/H] ? -1.5 obtained in the HERES survey. The snapshot spectra have been obtained with VLT/UVES and have typically S/N˜ 54 per pixel (ranging from 17 to 308), R˜20 000, ? = 3760-4980 Å. This sample represents the major part of the complete HERES sample of 373 stars; however, the CH strong content of the sample is not dealt with here. The spectra are analysed using an automated line profile analysis method based on the Spectroscopy Made Easy (SME) codes of Valenti & Piskunov. Elemental abundances of moderate precision (absolute rms errors of order 0.25 dex, relative rms errors of order 0.15 dex) have been obtained for 22 elements, C, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Sr, Y, Zr, Ba, La, Ce, Nd, Sm, and Eu, where detectable. Of these elements, 14 are usually detectable at the 3? confidence level for our typical spectra. The remainder can be detected in the least metal-poor stars of the sample, spectra with higher than average S/N, or when the abundance is enhanced. Among the sample of 253 stars, disregarding four previously known comparison stars, we find 8 r-II stars and 35 r-I stars. The r-II stars, including the two previously known examples CS 22892-052 and CS 31082-001, are centred on a metallicity of [Fe/H] = -2.81, with a very small scatter, on the order of 0.16 dex. The r-I stars are found across practically the entire metallicity range of our sample. We also find three stars with strong enhancements of Eu which are s-process rich. A significant number of new very metal-poor stars are confirmed: 49 stars with [Fe/H]<-3 and 181 stars with -3<[Fe/H]<-2. We find one star with [Fe/H]<-3.5. We find the scatter in the abundance ratios of Mg, Ca, Sc, Ti, Cr, Fe, Co, and Ni, with respect to Fe and Mg, to be similar to the estimated relative errors and thus the cosmic scatter to be small, perhaps even non-existent. The elements C, Sr, Y, Ba and Eu, and perhaps Zr, show scatter at [Fe/H] ? -2.5 significantly larger than can be explained from the errors in the analysis, implying scatter which is cosmic in origin. Significant scatter is observed in abundance ratios between light and heavy neutron-capture elements at low metallicity and low levels of r-process enrichment.

Barklem, P. S.; Christlieb, N.; Beers, T. C.; Hill, V.; Bessell, M. S.; Holmberg, J.; Marsteller, B.; Rossi, S.; Zickgraf, F.-J.; Reimers, D.

2005-08-01

210

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

SciTech Connect

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

Hansen, Terese; Andersen, Johannes; Nordstroem, Birgitta; Buchhave, Lars A. [Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Beers, Timothy C., E-mail: terese@fys.ku.dk, E-mail: ja@astro.ku.dk, E-mail: birgitta@astro.ku.dk, E-mail: beers@pa.msu.edu, E-mail: buchhave@astro.ku.dk [Department of Physics and Astronomy and JINA: Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 (United States)

2011-12-10

211

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

SciTech Connect

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

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

2001-11-06

212

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

213

The long-term evolution of neutron star merger remnants - I. The impact of r-process nucleosynthesis  

NASA Astrophysics Data System (ADS)

We follow the long-term evolution of the dynamic ejecta of neutron star mergers for up to 100 years and over a density range of roughly 40 orders of magnitude. We include the nuclear energy input from the freshly synthesized, radioactively decaying nuclei in our simulations and study its effects on the remnant dynamics. Although the nuclear heating substantially alters the long-term evolution, we find that running nuclear networks over purely hydrodynamic simulations (i.e. without heating) yields actually acceptable nucleosynthesis results. The main dynamic effect of the radioactive heating is to quickly smooth out inhomogeneities in the initial mass distribution, subsequently the evolution proceeds self-similarly and after 100 years the remnant still carries the memory of the initial binary mass ratio. We also explore the nucleosynthetic yields for two mass ejection channels. The dynamic ejecta very robustly produce `strong' r-process elements with A > 130 with a pattern that is essentially independent of the details of the merging system. From a simple model we find that neutrino-driven winds yield `weak' r-process contributions with 50 < A < 130 whose abundance patterns vary substantially between different merger cases. This is because their electron fraction, set by the ratio of neutrino luminosities, varies considerably from case to case. Such winds do not produce any 56Ni, but a range of radioactive isotopes that are long-lived enough to produce a second, radioactively powered electromagnetic transient in addition to the `macronova' from the dynamic ejecta. While our wind model is very simple, it nevertheless demonstrates the potential of such neutrino-driven winds for electromagnetic transients and it motivates further, more detailed neutrino-hydrodynamic studies. The properties of the mentioned transients are discussed in more detail in a companion paper.

Rosswog, S.; Korobkin, O.; Arcones, A.; Thielemann, F.-K.; Piran, T.

2014-03-01

214

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

SciTech Connect

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

Fatherly, N. [U.S. Army Corps of Engineers - Baltimore District, Baltimore, Maryland (United States); O'Neill, M.; Glemza, A. [EA Engineering, Science, and Technology, Baltimore, Maryland (United States)

2008-07-01

215

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

E-print Network

Theoretical studies of the nucleosynthesis origin of the heavy elements in our Solar System (S.S.) by the rapid neutron-capture process (r-process) still face the entwined uncertainties in the possible astrophysical scenarios and the nuclear-physics properties far from stability. In this paper we present results from the investigation of an r-process in the high-entropy wind (HEW) of core-collapse supernovae (here chosen as one of the possible scenarios for this nucleosynthesis process), using new nuclear-data input calculated in a consistent approach, for masses and $\\beta$-decay properties from the new finite-range droplet model FRDM(2012). The accuracy of the new mass model is 0.56 MeV with respect to {\\sc AME2003}, to which it was adjusted. We compare the new HEW r-process abundance pattern to the latest S.S. r-process residuals and to our earlier calculations with the nuclear-structure quantities based on FRDM(1992). Substantial overall and specific local improvements in the calculated pattern of the r-process between $A\\simeq 110$ and $^{209}$Bi, as well as remaining deficiencies are discussed in terms of the underlying spherical and deformed shell structure far from stability.

Karl-Ludwig Kratz; Khalil Farouqi; Peter Möller

2014-06-10

216

F A S T -T R A C K P A P E R Rupture processes of the 1999 August 17 Izmit and November 12  

E-print Network

broad-band data of the Global Seismograph Network, aftershock locations and mapped surface breaksÃ?zce (Turkey) earthquakes R. Tibi,1, * G. Bock,1 Y. Xia,1 M. Baumbach,1 H. Grosser,1 C. Milkereit,1 S. Karakisa Potsdam, Germany. E-mail: bock@gfz-potsdam.de 2 General Directorate of Disaster Affairs, Earthquake

Tibi, Rigobert

217

The New Model of Chemical Evolution of r-process Elements Based on the Hierarchical Galaxy Formation. I. Ba and Eu  

NASA Astrophysics Data System (ADS)

We investigate the chemical enrichment of r-process elements in the early evolutionary stages of the Milky Way halo within the framework of hierarchical galaxy formation using a semi-analytic merger tree. In this paper, we focus on heavy r-process elements, Ba and Eu, of extremely metal-poor (EMP) stars and give constraints on their astronomical sites. Our models take into account changes of the surface abundances of EMP stars by the accretion of interstellar medium (ISM). We also consider metal-enrichment of intergalactic medium by galactic winds and the resultant pre-enrichment of proto-galaxies. The trend and scatter of the observed r-process abundances are well reproduced by our hierarchical model with ~10% of core-collapse supernovae in low-mass end (~10 M ?) as a dominant r-process source and the star formation efficiency of ~10-10 yr-1. For neutron star mergers as an r-process source, their coalescence timescale has to be ~107 yr, and the event rates ~100 times larger than currently observed in the Galaxy. We find that the accretion of ISM is a dominant source of r-process elements for stars with [Ba/H] < -3.5. In this model, a majority of stars at [Fe/H] < -3 are formed without r-process elements, but their surfaces are polluted by the ISM accretion. The pre-enrichment affects ~4% of proto-galaxies, and yet, is surpassed by the ISM accretion in the surface of EMP stars.

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

2014-03-01

218

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

E-print Network

. Hertwig,"An Advanced Process Analysis System for Improving Chemical and Refinery Processes," Computers Chemical and Refinery Processes K. S. Telang, X. Chen, R. W. Pike and F. C. Knopf Louisiana State and refineries for process improvements. The system integrates programs for on-line optimization, chemical

Pike, Ralph W.

219

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

NASA Technical Reports Server (NTRS)

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

Kasahara, Hironori; Honda, Hiroki; Narita, Seinosuke

1989-01-01

220

Surface processes in microgravity for landing and sampling site selection of asteroid missions-Suggestions for MarcoPolo-R  

NASA Astrophysics Data System (ADS)

Surface properties of small asteroids are reviewed in this work focusing on microgravity related processes in order to give constrains for targeting sample acquisition by next missions, especially for MarcoPolo-R proposed by ESA. Based on our current knowledge and the planned capabilities of this mission, good chance exists to get answers for the following basic questions. Formation method of nanophase iron and amorphous ingredients in the regolith could be determined, surface particle size and regolith density estimation would also be gained, and with extrapolation to the rest of the surface, knowledge on transport processes, ages and results of cratering under special gravity-strength regime will be improved. Searching for fresh material on asteroid surface in general requires sophisticated effort, as small craters often do not produce much ejecta in microgravity, but the bright annuli around them could be the result of local surface disturbance, while slopes often exhibit fresh material. To identify these locations high albedo, bluer colour and occasionally the depth of 1 ?m absorption band could be useful as they often change parallel to each other. To identify the best area for sample acquisition addresses a strategic question: while smooth terrains with easy navigation and sample acquisition provide strongly weathered fine grains; steeper terrains give access to less weathered, material more representative for the whole asteroid, but navigation and mechanical sampling rise difficulties there.

Kereszturi, Akos

2014-10-01

221

MOTIONDEFINED FORM PROCESSING IN HUMAN VISION: A fMRI STUDY, S. Niyogi 1 , J. Reppas 2* , A. Dale 2 , and R. Tootell 2 . MIT Perceptual Science Section,  

E-print Network

MOTION­DEFINED FORM PROCESSING IN HUMAN VISION: A fMRI STUDY, S. Niyogi 1 , J. Reppas 2* , A. Dale 2 , and R. Tootell 2 . MIT Perceptual Science Section, Cambridge, MA. 1 Harvard Medical School, Charlestown, MA. 2 Purpose. We have studied the processing of motion­defined form in the human brain using

222

Nine New Metal-Poor Stars on the Subgiant and Red Horizontal Branches with High Levels of r-process Enhancement  

E-print Network

We report the discovery of nine metal-poor stars with high levels of r-process enhancement (+0.81red horizontal branch. We also analyze four previously-known r-process-enhanced metal-poor red giants. From this sample of 13 stars, we draw the following conclusions. (1) High levels of r-process enhancement are found in a broad range of stellar evolutionary states, reaffirming that this phenomenon is not associated with a chemical peculiarity of red giant atmospheres. (2) Only 1 of 10 stars observed at multiple epochs shows radial velocity variations, reaffirming that stars with high levels of r-process enhancement are not preferentially found among binaries. (3) Only 2 of the 13 stars are highly-enhanced in C and N, indicating that there is no connection between high levels of r-process enhancement and high levels of C and N. (4) The dispersions in [Sr/Ba] and [Sr/Eu] are larger than the dispersions in [Ba/Eu] and [Yb/Eu], suggesting that the...

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

2014-01-01

223

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

224

Astrocytes and Interneurons in Memory Processing in the Chick Hippocampus: Roles for G-Coupled Protein Receptors, GABA(B) and mGluR1  

Microsoft Academic Search

Glutamate and GABA acting at mGluR1 and GABAB receptors, respectively, have roles in memory processing in the hippocampus up to 35 min after bead discrimination learning\\u000a in the young chick. Activation of mGluR1 receptors is important at 2.5 and 30 min after training, but modulation of these\\u000a receptors between these two times has no effect on memory. This timing is similar to

Marie E. Gibbs; David N. Bowser

2009-01-01

225

Reaction temperature optimization procedure for the synthesis of ( R)-mandelonitrile by Prunus amygdalus hydroxynitrile lyase using a process model approach  

Microsoft Academic Search

The reaction temperature was optimized for the enzymatic synthesis of (R)-mandelonitrile in a biphasic system of aqueous buffer and methyl tert-butyl ether by including temperature effects in an existing process model. (R)-Mandelonitrile was synthesized by addition of hydrogen cyanide to benzaldehyde using Prunus amygdalus hydroxynitrile lyase as the catalyst. The reaction was investigated within a temperature range of 5 to

W. F Willeman; A. J. J Straathof; J. J Heijnen

2002-01-01

226

Process R&D for CIS-Based Thin-Film PV: Annual Technical Report, January 2003--January 2004  

SciTech Connect

This subcontract report describes Shell Solar Industries' outstanding progress in the initial commercialization of high-performance thin-film CIS technology. Cumulative production for 2002 exceeded 1 MW-about twice the production rate for 2001. SSI 2003 capacity was about 3 MW per year, whereas production for 2003 was just over 1.2 MW per year. Introducing the new product accounts for the main difference between production and capacity. Average laminate efficiency for 2003 was 11.0% with a full width of only 11% of the average. This distribution is nominally the same as the distribution for 2002, but with an about 33% increase in production volume. Line yield increased from about 60% in 2000 to about 85% in 2002. Maintenance of this high line yield was demonstrated during 2003. Process R&D during this and previous subcontract periods, both at SSI and in collaboration with NREL teams, has demonstrated the potential for further cost performance improvements: minimization of transients, increased efficiency, and improved packaging. Long-term outdoor stability has been demonstrated at NREL where {approx}30 x 30 cm and {approx} 30 x 120 cm modules with multiple prototype package designs have undergone testing for over 14 years. Field failure mechanisms related to particular package designs and errors during production have been clearly identified. Additional circuit plate or packaging process variables may have affected durability during particular production timeframes; when losses have been observed, the losses correlated with date of deployment or prototype module configuration. Prototype glass/glass packages for individual 40-W circuit plates have passed accelerated tests, including the damp-heat test. This package incorporates an edge seal developed in collaboration with the National Thin-Film PV Module Reliability Team. Developing and testing of 40-W glass/glass packages is being extended to a new 80-W product made using two nominally 40-W circuit plates laminated to a common front sheet.

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

2004-10-01

227

Smoking Gun or Smoldering Embers? A Possible r-process Kilonova Associated with the Short-Hard GRB 130603B  

E-print Network

We present Hubble Space Telescope optical and near-IR observations of the short-hard GRB 130603B (z=0.356) obtained 9.4 days post-burst. At the position of the burst we detect a red point source with m(F160W)=25.8+/-0.2 AB mag and m(F606W)>27.5 AB mag (3-sigma), corresponding to rest-frame absolute magnitudes of M_J -15.2 mag and M_B>-13.5 mag. A comparison to the early optical afterglow emission requires a decline rate of alpha_opt1.7 mag is also potentially consistent with the red optical colors of the afterglow at early time (F_nu nu^-1.6 in gri). Thus, an afterglow interpretation is feasible. Alternatively, the red color and faint absolute magnitude are due to emission from an r-process powered transient ("kilonova") produced by ejecta from the merger of an NS-NS or NS-BH binary, the most likely progenitors of short GRBs. In this scenario, the observed brightness implies an outflow with M_ej 0.01 Msun and v_ej 0.1c, in good agreement with the results of numerical merger simulations for roughly equal mass ...

Berger, E; Chornock, R

2013-01-01

228

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

229

Examining the Cross-Cultural Sensitivity of the Revised Two-Factor Study Process Questionnaire (R-SPQ-2F) and Validation of a Dutch Version  

PubMed Central

The Revised Two-Factor Study Process Questionnaire (R-SPQ-2F) is used to examine students’ study approaches in higher education. The questionnaire assumes to measure two factors: a deep and a surface study approach. Analyses into the validity and reliability of the original English R-SPQ-2F yielded positive results. In this study, we examined the degree to which these positive results can also be found for the Dutch version that we developed. By comparing our results with the results of earlier studies in different cultures, we conclude cross-cultural sensitivity is an important point to be borne in mind when using the R-SPQ-2F. Our research supports the validity and reliability of our Dutch version of the R-SPQ-2F. PMID:23342085

Stes, Ann; De Maeyer, Sven; Van Petegem, Peter

2013-01-01

230

THE EFFECTS OF ANTICOAGULATION AND PROCESSING ON ASSAYS OF IL6, sIL6R, sIL2R AND SOLUBLE TRANSFERRIN RECEPTOR  

Microsoft Academic Search

Levels of plasma cytokines, their receptors or immune-related peptides, are used in experimental and clinical medicine. However, no standards are available regarding the use of anticoagulants or blood processing including the technique of blood collection or time delay between blood sampling and centrifugation.Blood was collected from 10 patients in order to assay interleukin 6, soluble interleukin 6 receptor, soluble interleukin

R. De Jongh; J. Vranken; G. Vundelinckx; E. Bosmans; M. Maes; R. Heylen

1997-01-01

231

A heterozygous variant in the human cardiac miR-133 gene, MIR133A2, alters miRNA duplex processing and strand abundance  

PubMed Central

Background MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression. Sequential cleavage of miRNA precursors results in a ~22 nucleotide duplex of which one strand, the mature miRNA, is typically loaded into the RNA-induced silencing complex (RISC) while the passenger strand is degraded. Very little is known about how genetic variation might affect miRNA biogenesis and function. Results We re-sequenced the MIR1-1, MIR1-2, MIR133A1, MIR133A2, and MIR133B genes, that encode the cardiac-enriched miRNAs, miR-1 and miR-133, in 120 individuals with familial atrial fibrillation and identified 10 variants, including a novel 79T?>?C MIR133A2 substitution. This variant lies within the duplex at the 3? end of the mature strand, miR-133a-3p, and is predicted to prevent base-pairing and weaken thermostability at this site, favoring incorporation of the passenger strand, miR-133a-5p, into RISC. Genomic DNA fragments containing miR-133a-2 precursor sequences with 79T and 79C alleles were transfected into HeLa cells. On Northern blotting the 79T allele showed strong expression of miR-133a-3p with weak expression of miR-133a-5p. In contrast, the 79C allele had no effect on miR-133a-3p but there was a significant increase (mean 3.6-fold) in miR-133a-5p levels. Deep sequencing of small RNA libraries prepared from normal human and murine atria confirmed that nearly all the mature miR-133a was comprised of miR-133a-3p and that levels of miR-133a-5p were very low. A number of isomiRs with variations at 5? and 3? ends were identified for both miR-133a-3p and miR-133a-5p, with 2 predominant miR-133a-3p isomiRs and one predominant miR-133a-5p isomiR. Bioinformatics analyses indicate that the major miR-133a-3p and 5p isomiRs have numerous predicted target mRNAs, only a few of which are in common. Conclusions Multiple miR-133a isomiRs with potential different mRNA target profiles are present in the atrium in humans and mice. We identified a human 79T?>?C MIR133A2 variant that alters miRNA processing and results in accumulation of the miR-133a-5p strand that is usually degraded. PMID:23497314

2013-01-01

232

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

PubMed

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. PMID:10357822

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

1999-06-01

233

Properties and Processes for Cryogenic Refrigeration R. Radebaugh, P. Bradley, M. Lewis (838), J. Gary, and A. O'Gallagher (ITL)  

E-print Network

Properties and Processes for Cryogenic Refrigeration R. Radebaugh, P. Bradley, M. Lewis (838), J. Gary, and A. O'Gallagher (ITL) Cryogenic temperatures are required for many technology areas, including. Material properties at cryogenic temperatures also are needed by industry for the design of cryogenic

Magee, Joseph W.

234

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

ERIC Educational Resources Information Center

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

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

2008-01-01

235

Do product innovation and news about the R&D process produce large price changes and overreaction? The case of pharmaceutical stock prices  

Microsoft Academic Search

Do extreme price changes of pharmaceutical stocks reflect unexpected scientific information produced during the drug R&D process, especially the approval of new drugs, but also pre- and clinical trial results, recalls and withdrawals? Do stock prices initially overreact to such information? We modelled market-adjusted daily changes in stock prices of the 17 biggest pharmaceutical firms worldwide for the period from

Jorge V. Pérez-Rodríguez; Beatriz G. L. Valcarcel

2012-01-01

236

Do product innovation and news about the R&D process produce large price changes and overreaction? The case of pharmaceutical stock prices  

Microsoft Academic Search

Do extreme price changes of pharmaceutical stocks reflect unexpected scientific information produced during the drug R&D process, especially the approval of new drugs, but also pre- and clinical trial results, recalls and withdrawals? Do stock prices initially overreact to such information? We modelled market-adjusted daily changes in stock prices of the 17 biggest pharmaceutical firms worldwide for the period from

Jorge V. Pérez-Rodríguez; Beatriz G. L. Valcarcel

2011-01-01

237

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

E-print Network

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

Ribes, Aurélien

238

The Hamburg/ESO R-process Enhanced Star survey (HERES). I. Project description, and discovery of two stars with strong enhancements of neutron-capture elements  

NASA Astrophysics Data System (ADS)

We report on a dedicated effort to identify and study metal-poor stars strongly enhanced in r-process elements ([r/Fe]>1 dex; hereafter r-II stars), the Hamburg/ESO R-process Enhanced Star survey (HERES). Moderate-resolution (˜2 Å) follow-up spectroscopy has been obtained for metal-poor giant candidates selected from the Hamburg/ESO objective-prism survey (HES) as well as the HK survey to identify sharp-lined stars with [Fe/H]<-2.5 dex. For several hundred confirmed metal-poor giants brighter than B˜ 16.5 mag (most of them from the HES), ``snapshot'' spectra (R˜ 20 000; S/N ˜ 30 per pixel) are being obtained with VLT/UVES, with the main aim of finding the 2-3% r-II stars expected to be among them. These are studied in detail by means of higher resolution and higher S/N spectra. In this paper we describe a pilot study based on a set of 35 stars, including 23 from the HK survey, eight from the HES, and four comparison stars. We discovered two new r-II stars, CS 29497-004 ([Eu/Fe]=1.64± 0.22) and CS 29491-069 ([Eu/Fe]=1.08± 0.23). A first abundance analysis of CS 29497-004 yields that its abundances of Ba to Dy are on average enhanced by 1.5 dex with respect to iron and the Sun and match a scaled solar r-process pattern well, while Th is underabundant relative to that pattern by 0.3 dex, which we attribute to radioactive decay. That is, CS 29497-004 seems not to belong to the class of r-process enhanced stars displaying an ``actinide boost'', like CS 31082-001 (Hill et al. 2002), or CS 30306-132 (Honda et al. 2004b). The abundance pattern agrees well with predictions of the phenomenological model of Qian & Wasserburg. Based in large part on observations collected at the European Southern Observatory, Paranal, Chile (proposal number 68.B-0320).}

Christlieb, N.; Beers, T. C.; Barklem, P. S.; Bessell, M.; Hill, V.; Holmberg, J.; Korn, A. J.; Marsteller, B.; Mashonkina, L.; Qian, Y.-Z.; Rossi, S.; Wasserburg, G. J.; Zickgraf, F.-J.; Kratz, K.-L.; Nordström, B.; Pfeiffer, B.; Rhee, J.; Ryan, S. G.

2004-12-01

239

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

PubMed

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

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

2012-06-29

240

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

PubMed Central

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

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

2012-01-01

241

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

NASA Astrophysics Data System (ADS)

The ? decays of very neutron-rich nuclides in the Co-Zn region were studied experimentally at the National Superconducting Cyclotron Laboratory using the NSCL ?-counting station in conjunction with the neutron detector NERO. We measured the branchings for ?-delayed neutron emission (Pn values) for Co74 (18±15%) and Ni75-77 (10±2.8%, 14±3.6%, and 30±24%, respectively) for the first time, and remeasured the Pn values of Cu77-79, Zn79,81, and Ga82. For Cu77-79 and for Zn81 we obtain significantly larger Pn values compared to previous work. While the new half-lives for the Ni isotopes from this experiment had been reported before, we present here in addition the first half-life measurements of Co75 (30±11 ms) and Cu80 (170-50+110 ms). Our results are compared with theoretical predictions, and their impact on various types of models for the astrophysical rapid neutron-capture process (r-process) is explored. We find that with our new data, the classical r-process model is better able to reproduce the A=78-80 abundance pattern inferred from the solar abundances. The new data also influence r-process models based on the neutrino-driven high-entropy winds in core collapse supernovae.

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

2010-08-01

242

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

EPA Science Inventory

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

243

Ecol. 131, 155171 (1997). 13. Wills, C. & Condit, R. Similar non-random processes maintain diversity in two tropical rainforests.  

E-print Network

. B. & Hubbell, S. P. Strong density- and diversity-related effects help to maintain tree species. Ecology 65, 1705­1712 (1984). 18. Gilbert, G. S., Hubbell, S. P. & Foster, R. B. Density and distance, 1302­1310 (1978). 25. Hubbell, S. P. Seed predation and the coexistence of tree species in tropical

Thompson, John N.

244

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

245

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

E-print Network

(x) Fr(x) g = p, (1) · v = 0. (2) The viscosity of glass strongly depends on temperature. The temperature , typical temperature jump T = 350 C, typical specific heat for glass cpglass = 1.2 · 103 J/(kg K) and airModelling the Glass Press-Blow Process S.M.A. Allaart-Bruin, B.J. van der Linden, and R

Eindhoven, Technische Universiteit

246

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. PMID:23741154

Anantha, Narayana D. B.

2013-01-01

247

The nuclear physics input to astrophysics modelling, and the r- and p-processes: Where do we stand 50 years after B^2FH and Cameron?  

NASA Astrophysics Data System (ADS)

This is a brief review of the progress made since the seminal contributions to the foundations of the theory of nucleosynthesis by M. Burbidge, G. Burbidge, Fowler and Hoyle, and by Cameron. The reviewed topics are (1) the nuclear physics input to the nucleosynthesis models (nuclear masses, fission, rates of ?-decays, neutrino reactions, photoreactions, and nuclear charged particle-induced or neutron-induced reactions), (2) the nuclear physics and astrophysics aspects of the r-process, and (3) the same items for the p-process.

Arnould, M.

2008-11-01

248

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

Microsoft Academic Search

beta-delayed neutron emission branchings (or upper limits) for neutron rich Rh116-120, Pd120-122, and Ag124 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 Tc114-115, Ru114-118, Rh116-121, and Pd119-124 near the proposed path of the r-process have also

F. Montes; A. Estrade; P. T. Hosmer; S. N. Liddick; P. F. Mantica; A. C. Morton; W. F. Mueller; M. Ouellette; E. Pellegrini; P. Santi; H. Schatz; A. Stolz; B. E. Tomlin; O. Arndt; K.-L. Kratz; B. Pfeiffer; P. Reeder; W. B. Walters; A. Aprahamian; A. Wöhr

2006-01-01

249

Development of a process model to describe the synthesis of (R)-mandelonitrile by Prunus amygdalus hydroxynitrile lyase in an aqueous-organic biphasic reactor.  

PubMed

A process model for the enzymatic synthesis of (R)-cyanohydrins in an aqueous-organic biphasic-stirred tank reactor was developed. The conversion of benzal-dehyde into (R)-mandelonitrile, catalyzed by Prunus amygdalus hydroxynitrile lyase at 5 degrees C and pH 5.5, was chosen as a model system with methyl tert-butyl ether as the organic phase. The process model consisted of a description of the reaction kinetics, mass transfer kinetics, and the mass balances for both the aqueous and the organic phase. Values for the enzyme kinetic parameters, according to ordered bi-uni kinetics, the lumped mass transfer coefficient for benzaldehyde, and the partition coefficients were determined separately. The process model is validated by using 11 experimental data sets of batch conversions in the aqueous-organic biphasic-stirred tank reactor. In these 11 experiments, different enzyme concentrations and phase volume ratios were used. The model was found to be valid with respect to both the conversion and the enantiomeric excess. To synthesize cyanohydrins with a high enantiomeric excess, the enzyme is required to work at mass transfer limited conditions. The developed process model will be used to investigate other process concepts and other substrates. PMID:11753932

Willeman, Wouter F; Gerrits, Pieter Jan; Hanefeld, Ulf; Brussee, Johannes; Straathof, Adrie J J; van der Gen, Arne; Heijnen, Joseph J

2002-02-01

250

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

251

NATIONAL BRAIN RESEARCH CENTRE (NBRC), Manesar-122051, Gurgaon, requires a "Senior R&D Engineer" for signal and image processing  

E-print Network

applied : 2. Full Name in Capitals : 3. Date of birth : 4. Gender : 5. Category : 6. Marital status : 7: · Medical Signal/Image processing ­ MRI images and MRS / fMRI data from brain · Research data analysis

Mandal, Pravat K.

252

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 ...

253

A KINETIC MODEL FOR H2O2/UV PROCESS IN A COMPLETELY MIXED BATCH REACTOR. (R825370C076)  

EPA Science Inventory

A dynamic kinetic model for the advanced oxidation process (AOP) using hydrogen peroxide and ultraviolet irradiation (H2O2/UV) in a completely mixed batch reactor (CMBR) is developed. The model includes the known elementary chemical and photochemical reac...

254

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. PMID:21463562

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

2013-01-01

255

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. PMID:22916032

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

2012-01-01

256

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

SciTech Connect

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

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

2013-09-30

257

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

258

Cross-section measurement of 9Be(?,n)8Be and implications for ?+?+n?9Be in the r process  

NASA Astrophysics Data System (ADS)

Models of the r process are sensitive to the production rate of 9Be because, in explosive environments rich in neutrons, ?(?n,?)9Be is the primary mechanism for bridging the stability gaps at A=5 and A=8. The ?(?n,?)9Be reaction represents a two-step process, consisting of ?+??8Be followed by 8Be(n,?)9Be. We report here on a new absolute cross-section measurement for the 9Be(?,n)8Be reaction conducted using a highly efficient, 3He-based neutron detector and nearly monoenergetic photon beams, covering energies from E?=1.5 MeV to E?=5.2 MeV, produced by the High Intensity ?-ray Source of Triangle Universities Nuclear Laboratory. In the astrophysically important threshold energy region, the present cross sections are 40% larger than those found in most previous measurements and are accurate to ±10% (95% confidence). The revised thermonuclear ?(?n,?)9Be reaction rate could have implications for the r process in explosive environments such as type II supernovae.

Arnold, C. W.; Clegg, T. B.; Iliadis, C.; Karwowski, H. J.; Rich, G. C.; Tompkins, J. R.; Howell, C. R.

2012-04-01

259

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. PMID:23482395

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

2013-01-01

260

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...

261

INVESTIGATION OF AQUEOUS BIPHASIC SYSTEMS FOR THE SEPARATIONS OF LIGNINS FROM CELLULOSE IN THE PAPER PULPING PROCESS. (R826732)  

EPA Science Inventory

In efforts to apply a polymer-based aqueous biphasic system (ABS) extraction to the paper pulping process, the study of the distribution of various lignin and cellulosic fractions in ABS and the effects of temperature on system composition and solute partitioning have been inv...

262

1154 D. R. Warren et al. Copyright 2007 John Wiley & Sons, Ltd. Earth Surf. Process. Landforms 32, 11541163 (2007)  

E-print Network

velocity; instream processing; large wood; large woody debris; debris dam; Hubbard Brook *Correspondence to in the accumulation of large wood and debris dams in a 66-year chronosequence formed by five watersheds within and abundance of large wood in each stream to test whether large wood abundance could be linked to nitrate

Hall Jr., Robert O.

263

Required precision of mass and half-life measurements for r-process nuclei planned at future RI-beam facilities  

E-print Network

In order to understand the r-process nucleosynthesis, we suggest precision required for mass and beta-decay half-life measurements planned at future RI-beam facilities. To satisfy a simple requirement that we put on nuclear model predictions, it is concluded that the detectors for the mass measurements must have a precision of 1sigma ~half-life measurements demand a precision of 1sigma ~half-life measurements. This analysis aims to provide a first rough guide for ongoing detector developments.

Y. Motizuki; T. Tachibana; S. Goriely; H. Koura

2004-06-12

264

Beta-decay half-lives and beta-delayed neutron emisison probabilities of nuclei in the region A. 110, relevant for the r-process  

SciTech Connect

Measurements of the {beta}-decay properties of A {approx}< 110 r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory, at Michigan State University. {beta}-decay half-lives for {sup 105}Y, {sup 106,107}Zr and {sup 108,111}Mo, along with ,B-delayed neutron emission probabilities of 104Y, 109,11OMo and upper limits for 105Y, 103-107Zr and 108,111 Mo have been measured for the first time. Studies on the basis of the quasi-random phase approximation are used to analyze the ground-state deformation of these nuclei.

Moller, Peter [Los Alamos National Laboratory; Pereira, J [MSU; Hennrich, S [MSU; Aprahamian, A [UNIV OF NOTRE DAME; Arndt, O [GERMANY; Becerril, A [MSU; Elliot, T [MSU; Estrade, A [MSU; Galaviz, D [MSU; Kessler, R [UNIV MAINZ; Kratz, K - L [GERMANY; Lorusso, G [MSU; Mantica, P F [MSU; Matos, M [MSU; Montes, F [MSU; Pfeiffer, B [UNIV MAINZ; Schatz, F [MSU; Schnorrenberger, L [GERMANY; Smith, E [MSU; Stolz, A [MSU; Quinn, M [UNIV OF NOTRE DAME; Walters, W B [UNIV OF MARYLAND; Wohr, A [UNIV OF NOTRE DAME

2009-01-01

265

Beta-decay half-lives and beta-delayed neutron emission probabilities of nuclei in the region below A=110, relevant for the r-process  

E-print Network

Measurements of the beta-decay properties of r-process nuclei below A=110 have been completed at the National Superconducting Cyclotron Laboratory, at Michigan State University. Beta-decay half-lives for Y-105, Zr-106,107 and Mo-111, along with beta-delayed neutron emission probabilities of Y-104, Mo-109,110 and upper limits for Y-105, Zr-103,104,105,106,107 and Mo-108,111 have been measured for the first time. Studies on the basis of the quasi-random phase approximation are used to analyze the ground-state deformation of these nuclei.

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

2009-02-10

266

{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)] [Institute of Mathematics, 630090, Novosibirsk (Russian Federation); Serbo, V.G. [Novosibirsk State University, 630090, Novosibirsk (Russian Federation)] [Novosibirsk State University, 630090, Novosibirsk (Russian Federation)

1994-03-01

267

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

268

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

NASA Astrophysics Data System (ADS)

?-delayed neutron emission branchings (or upper limits) for neutron rich Rh116-120, Pd120-122, and Ag124 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 Tc114-115, Ru114-118, Rh116-121, and Pd119-124 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 Rh120, which is found to be much smaller than predicted.

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

2006-03-01

269

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

SciTech Connect

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

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

1989-12-01

270

Astrocytes and interneurons in memory processing in the chick hippocampus: roles for G-coupled protein receptors, GABA(B) and mGluR1.  

PubMed

Glutamate and GABA acting at mGluR1 and GABA(B) receptors, respectively, have roles in memory processing in the hippocampus up to 35 min after bead discrimination learning in the young chick. Activation of mGluR1 receptors is important at 2.5 and 30 min after training, but modulation of these receptors between these two times has no effect on memory. This timing is similar to the action of glutamate on NMDA receptors. The GABA(B) antagonist, phaclofen, and the inhibitor of astrocytic oxidative metabolism, fluoroacetate, inhibited memory when injected between 2.5 and 30 min. Paradoxically, a high dose of the GABA(B) agonist, baclofen, also inhibited memory, but a low dose promoted memory consolidation--an effect possibly caused by too much information and loss of the 'message'. These results are interpreted in terms interactions between interneurons, astrocytes and pyramidal cells and demonstrate the importance of all cell types in memory processing in the hippocampus. PMID:19415487

Gibbs, Marie E; Bowser, David N

2009-10-01

271

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. PMID:16316434

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

2005-01-01

272

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

2012-10-01

273

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

EPA Science Inventory

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

274

Hierarchical recruitment into nascent ribosomes of assembly factors required for 27SB pre-rRNA processing in Saccharomyces cerevisiae  

PubMed Central

To better define the roles of assembly factors required for eukaryotic ribosome biogenesis, we have focused on one specific step in maturation of yeast 60?S ribosomal subunits: processing of 27SB pre-ribosomal RNA. At least 14 assembly factors, the ‘B-factor’ proteins, are required for this step. These include most of the major functional classes of assembly factors: RNA-binding proteins, scaffolding protein, DEAD-box ATPases and GTPases. We have investigated the mechanisms by which these factors associate with assembling ribosomes. Our data establish a recruitment model in which assembly of the B-factors into nascent ribosomes ultimately leads to the recruitment of the GTPase Nog2. A more detailed analysis suggests that this occurs in a hierarchical manner via two largely independent recruiting pathways that converge on Nog2. Understanding recruitment has allowed us to better determine the order of association of all assembly factors functioning in one step of ribosome assembly. Furthermore, we have identified a novel subcomplex composed of the B-factors Nop2 and Nip7. Finally, we identified a means by which this step in ribosome biogenesis is regulated in concert with cell growth via the TOR protein kinase pathway. Inhibition of TOR kinase decreases association of Rpf2, Spb4, Nog1 and Nog2 with pre-ribosomes. PMID:22735702

Talkish, Jason; Zhang, Jingyu; Jakovljevic, Jelena; Horsey, Edward W.; Woolford, John L.

2012-01-01

275

Cost efficiency analysis of modern cytocentrifugation methods versus liquid based (Cytyc Thinprep(R)) processing of urinary samples  

PubMed Central

Background/Aims: Liquid based cytology (LBC) was developed as a replacement for cytocentrifugation in the treatment of cell suspensions. Because accurate data comparing the quality and total cost of modern cytocentrifugation methods versus LBC in non-gynaecological samples are not available, this study was designed to investigate these issues. Methods: The study comprised 224 urine samples treated with the Thermo Shandon Cytospin® 4 using reusable TPX® chambers, disposable Cytofunnels® for samples up to 0.5 ml, and disposable Megafunnels® for samples up to 6 ml. Each method was compared with the Cytyc Thinprep® processing of a paired sample. Quality was assessed by scoring cellularity, fixation, red blood cells, leucocytes, abnormalities of urothelial cells, and suitability for molecular studies. Wage costs, investment, and consumables allowed a “total cost” to be calculated on the basis of 200 specimens/month. Total cost and quality combined were used to calculate an index of total quality (ITQ). Results: Cytocentrifugation with disposable chambers resulted in a global quality superior to that of Cytyc Thinprep LBC. Preparation and screening times were 2.25 and 1.33–2 times greater when using LBC compared with cytocentrifugation. The total cost each month reached 1960.23 $ to 2833.43 $ for cytocentrifugation methods and 5464.95 $ for Cytyc Thinprep LBC (92.8–178.8% increased cost). ITQ of cytocentrifugation with disposable chambers surpassed that of Cytyc Thinprep LBC (37.25/32.08 and 9.98, respectively). Conclusion: Cytyc Thinprep LBC and cytocentrifugation are both appropriate methods for cytology based molecular studies, but cytocentrifugation remains the quality standard for current treatment of urinary samples because of its lower cost. PMID:15509686

Piaton, E; Hutin, K; Faynel, J; Ranchin, M-C; Cottier, M

2004-01-01

276

Identification of protein factors and U3 snoRNAs from a Brassica oleracea RNP complex involved in the processing of pre-rRNA.  

PubMed

We report on the structural characterization of a functional U3 snoRNA ribonucleoprotein complex isolated from Brassica oleracea. The BoU3 snoRNP complex (formerly NF D) binds ribosomal DNA (rDNA), specifically cleaves pre-rRNA at the primary cleavage site in vitro and probably links transcription to early pre-rRNA processing in vivo. Using a proteomic approach we have identified 62 proteins in the purified BoU3 snoRNP fraction, including small RNA associated proteins (Fibrillarin, NOP5/Nop58p, Diskerin/Cbf5p, SUS2/PRP8 and CLO/GFA1/sn114p) and 40S ribosomal associated proteins (22 RPS and four ARCA-like proteins). Another major protein group is composed of chaperones/chaperonins (HSP81/TCP-1) and at least one proteasome subunit (RPN1a). Remarkably, RNA-dependent RNA polymerase (RdRP) and Tudor staphylococcal nuclease (TSN) proteins, which have RNA- and/or DNA-associated activities, were also revealed in the complex. Furthermore, three U3 snoRNA variants were identified in the BoU3 snoRNP fraction, notably an evolutionarily conserved and variable stem loop structure located just downstream from the C-box domain of the U3 sequence structures. We conclude that the BoU3 snoRNP complex is mainly required for 40S pre-ribosome synthesis. It is also expected that U3 snoRNA variants and interacting proteins might play a major role in BoU3 snoRNP complex assembly and/or function. This study provides a basis for further investigation of these novel ribonucleoprotein factors and their role in plant ribosome biogenesis. PMID:19891704

Samaha, Hala; Delorme, Valérie; Pontvianne, Frederic; Cooke, Richard; Delalande, Francois; Van Dorsselaer, Alain; Echeverria, Manuel; Sáez-Vásquez, Julio

2010-02-01

277

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. PMID:23268442

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

2013-01-01

278

A Leu to Ile but not Leu to Val change at HIV-1 reverse transcriptase codon 74 in the background of K65R mutation leads to an increased processivity of K65R+L74I enzyme and a replication competent virus  

PubMed Central

Background The major hurdle in the treatment of Human Immunodeficiency virus type 1 (HIV-1) includes the development of drug resistance-associated mutations in the target regions of the virus. Since reverse transcriptase (RT) is essential for HIV-1 replication, several nucleoside analogues have been developed to target RT of the virus. Clinical studies have shown that mutations at RT codon 65 and 74 which are located in ?3-?4 linkage group of finger sub-domain of RT are selected during treatment with several RT inhibitors, including didanosine, deoxycytidine, abacavir and tenofovir. Interestingly, the co-selection of K65R and L74V is rare in clinical settings. We have previously shown that K65R and L74V are incompatible and a R?K reversion occurs at codon 65 during replication of the virus. Analysis of the HIV resistance database has revealed that similar to K65R+L74V, the double mutant K65R+L74I is also rare. We sought to compare the impact of L?V versus L?I change at codon 74 in the background of K65R mutation, on the replication of doubly mutant viruses. Methods Proviral clones containing K65R, L74V, L74I, K65R+L74V and K65R+L74I RT mutations were created in pNL4-3 backbone and viruses were produced in 293T cells. Replication efficiencies of all the viruses were compared in peripheral blood mononuclear (PBM) cells in the absence of selection pressure. Replication capacity (RC) of mutant viruses in relation to wild type was calculated on the basis of antigen p24 production and RT activity, and paired analysis by student t-test was performed among RCs of doubly mutant viruses. Reversion at RT codons 65 and 74 was monitored during replication in PBM cells. In vitro processivity of mutant RTs was measured to analyze the impact of amino acid changes at RT codon 74. Results Replication kinetics plot showed that all of the mutant viruses were attenuated as compared to wild type (WT) virus. Although attenuated in comparison to WT virus and single point mutants K65R, L74V and L74I; the double mutant K65R+L74I replicated efficiently in comparison to K65R+L74V mutant. The increased replication capacity of K65R+L74I viruses in comparison to K65R+L74V viruses was significant at multiplicity of infection 0.01 (p = 0.0004). Direct sequencing and sequencing after population cloning showed a more pronounced reversion at codon 65 in viruses containing K65R+L74V mutations in comparison to viruses with K65R+L74I mutations. In vitro processivity assays showed increased processivity of RT containing K65R+L74I in comparison to K65R+L74V RT. Conclusions The improved replication kinetics of K65R+L74I virus in comparison to K65R+L74V viruses was due to an increase in the processivity of RT containing K65R+L74I mutations. These observations support the rationale behind structural functional analysis to understand the interactions among unique RT mutations that may emerge during the treatment with specific drug regimens. PMID:21255423

2011-01-01

279

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

NASA Astrophysics Data System (ADS)

Submicron particles collected on Teflon filters aboard the R/V Ronald Brown during the Texas Air Quality Study and Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS/GoMACCS) 2006 in and around the port of Houston, Texas, were measured by Fourier transform infrared (FTIR) and X-ray fluorescence for organic functional groups and elemental composition. Organic mass (OM) concentrations (1-25 ?g m-3) for ambient particle samples measured by FTIR showed good agreement with measurements made with an aerosol mass spectrometer. The fractions of organic mass identified as alkane and carboxylic acid groups were 47% and 32%, respectively. Three different types of air masses were identified on the basis of the air mass origin and the radon concentration, with significantly higher carboxylic acid group mass fractions in air masses from the north (35%) than the south (29%) or Gulf of Mexico (26%). Positive matrix factorization analysis attributed carboxylic acid fractions of 30-35% to factors with mild or strong correlations (r > 0.5) to elemental signatures of oil combustion and 9-24% to wood smoke, indicating that part of the carboxylic acid fraction of OM was formed by the same sources that controlled the metal emissions, namely the oil and wood combustion activities. The implication is that a substantial part of the measured carboxylic acid contribution was formed independently of traditionally "secondary" processes, which would be affected by atmospheric (both photochemical and meteorological) conditions and other emission sources. The carboxylic acid group fractions in the Gulf of Mexico and south air masses (GAM and SAM, respectively) were largely oil combustion emissions from ships as well as background marine sources, with only limited recent land influences (based on radon concentrations). Alcohol groups accounted for 14% of OM (mostly associated with oil combustion emissions and background sources), and amine groups accounted for 4% of OM in all air masses. Organosulfate groups were found in GAM and SAM, accounting for 1% and 3% of OM, respectively. Two thirds of the OM and oxygen-to-carbon (O/C) measured could be attributed to oil and wood combustion sources on the basis of mild or strong correlations to coemitted, nonvolatile trace metals, with the remaining one third being associated with atmospherically processed organic aerosol. The cloud condensation nuclei (CCN) fraction (normalized by total condensation nuclei) had weak correlations to the alcohol and amine group fractions and mild correlation with O/C, also varying inversely with alkane group fraction. The chemical components that influenced f(RH) were sulfate, organic, and nitrate fraction, but this contrast is consistent with the size-distribution dependence of CCN counters and nephelometers.

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

2009-04-01

280

Introducing the Fission-Fusion Reaction Process: Using a Laser-Accelerated Th Beam to produce Neutron-Rich Nuclei towards the N=126 Waiting Point of the r Process  

E-print Network

We propose to produce neutron-rich nuclei in the range of the astrophysical r-process around the waiting point N=126 by fissioning a dense laser-accelerated thorium ion bunch in a thorium target (covered by a CH2 layer), where the light fission fragments of the beam fuse with the light fission fragments of the target. Via the 'hole-boring' mode of laser Radiation Pressure Acceleration using a high-intensity, short pulse laser, very efficiently bunches of 232Th with solid-state density can be generated from a Th layer, placed beneath a deuterated polyethylene foil, both forming the production target. Th ions laser-accelerated to about 7 MeV/u will pass through a thin CH2 layer placed in front of a thicker second Th foil closely behind the production target and disintegrate into light and heavy fission fragments. In addition, light ions (d,C) from the CD2 production target will be accelerated as well to about 7 MeV/u, inducing the fission process of 232Th also in the second Th layer. The laser-accelerated ion bunches with solid-state density, which are about 10^14 times more dense than classically accelerated ion bunches, allow for a high probability that generated fission products can fuse again. In contrast to classical radioactive beam facilities, where intense but low-density radioactive beams are merged with stable targets, the novel fission-fusion process draws on the fusion between neutron-rich, short-lived, light fission fragments both from beam and target. The high ion beam density may lead to a strong collective modification of the stopping power in the target, leading to significant range enhancement. Using a high-intensity laser as envisaged for the ELI-Nuclear Physics project in Bucharest (ELI-NP), estimates promise a fusion yield of about 10^3 ions per laser pulse in the mass range of A=180-190, thus enabling to approach the r-process waiting point at N=126.

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

2010-07-07

281

Ngl2p is a Ccr4p-like RNA nuclease essential for the final step in 3'-end processing of 5.8S rRNA in Saccharomyces cerevisiae.  

PubMed Central

Saccharomyces cerevisiae contains three nonessential genes (NGL1, NGL2, and NGL3) that encode proteins containing a domain with similarity to a Mg(2+)-dependent endonuclease motif present in the mRNA deadenylase Ccr4p. We have investigated a possible role of these proteins in rRNA processing, because for many of the pre-rRNA processing steps, the identity of the responsible nuclease remains elusive. Analysis of RNA isolated from cells in which the NGL2 gene has been inactivated (ngl2delta) demonstrates that correct 3'-end formation of 5.8S rRNA at site E is strictly dependent on Ngl2p. No role in pre-rRNA processing could be assigned to Ngl1p and Ngl3p. The 3'-extended 5.8S rRNA formed in the ngl2delta mutant is slightly shorter than the 6S precursor previously shown to accumulate upon combined deletion of the 3' --> 5' exonuclease-encoding REX1 and REX2 genes or upon depletion of the exosomal subunits Rrp40p or Rrp45p. Thus, our data add a further component to the set of nucleases required for correct 3'-end formation of yeast 5.8S rRNA. PMID:12358428

Faber, Alex W; Van Dijk, Marie; Raue, Hendrik A; Vos, Jan C

2002-01-01

282

Nitrogen gas-solid reaction process and basic magnetism of the interstitially modified rare-earth 3d transition-metal nitrides R2Fe17N3 (R=Y, Ce, Nd, Sm) and Y2Co17N3  

Microsoft Academic Search

In this paper, we present our recent results of studies of the nitrogen absorption process, magnetization measurements, and neutron powder-diffraction measurements for interstitially modified nitrides R2Fe17N3 (R=Y, Ce, Nd, and Sm) and Y2Co17N3. (1) The studies of nitrogen absorption rates in the Sm2Fe17 under various N2-gas pressure up to 6 MPa indicated that the nitrogen absorption into grain interior is

Keiichi Koyama; Hironobu Fujii

2000-01-01

283

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

284

Ptc6 Is Required for Proper Rapamycin-Induced Down-Regulation of the Genes Coding for Ribosomal and rRNA Processing Proteins in S. cerevisiae  

PubMed Central

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

Gonzalez, Asier; Casado, Carlos; Arino, Joaquin; Casamayor, Antonio

2013-01-01

285

Introducing the Fission-Fusion Reaction Process: Using a Laser-Accelerated Th Beam to produce Neutron-Rich Nuclei towards the N=126 Waiting Point of the r Process  

E-print Network

We propose to produce neutron-rich nuclei in the range of the astrophysical r process around the waiting point N=126 by fissioning a dense laser-accelerated thorium ion bunch in a thorium target (covered by a polyethylene layer), where the light fission fragments of the beam fuse with the light fission fragments of the target. Via laser Radiation Pressure Acceleration using a high-intensity, short pulse laser, very efficiently bunches of solid state density of 232Th can be generated from a first Th production target, placed on a CH2 backing. Laser accelerated Th ions with about 7 MeV/u will pass through a thin polyethylene layer placed in front of a thicker second Th foil closely behind the first target and desintegrate into light and heavy fission fragments. In addition light ions (p,C) from the CH2 backing of the first Th target will be accelerated as well, inducing the fission process of 232Th also in the second Th target. The laser-accelerated ion bunches with solid state density, which are about 10^15 ti...

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

2010-01-01

286

Overexpression of interleukin-8 receptor 2 (IL-8R2) indicates better prognosis in esophageal adenocarcinoma and squamous cell carcinoma procession.  

PubMed

Researches have showed that interleukin family or receptors play a role in many human tumor progressions including esophageal carcinoma. In this study, we examined the expression of interleukin-8 receptor 2 (IL-8R2) and analyze the relationship between it and esophageal carcinoma clinical characteristics. IL-8R2 protein expression was confirmed by immunohistochemistry and immunofluorescence arrays and was analyzed further via Western blot and qRT-PCR analysis in frozen tissues. The correlation between their expression levels and clinical characteristics were evaluated by Mann-Whitney and Kruskal-Wallis test. Via Kaplan-Meier plots and Cox proportional hazard models, overall survival (OS) was analyzed. Compared with normal esophageal tissue, IL-8R2 protein was overexpressed significantly in esophageal cancer (p < 0.05) and was observed both in cytoplasm and nuclear. The lower expression of IL-8R2 protein was observed with higher p staging of esophageal cancer, and the significant association between them was confirmed (p = 0.000), and in advanced p T stage, the similar result was obtained (p = 0.015); however, compared with lymph node metastasis-negative group, it is no significant difference in positive group (p = 0.152). In a Kaplan-Meier analysis, compared with IL-8R2 low expression, IL-8R2 high expression identified a group of patients with the longest OS. Cox proportional hazard models revealed that IL-8R2 predicted long time to OS. The higher expression of IL-8R2 was found in early esophageal carcinoma, which may indicate that IL-8R2 plays an important role and is better prognostic factor in esophageal cancer development. PMID:24972913

Liang, Bing; Zhao, Hui; Che, Jian-Bo; Wang, Hao-Jie; Shi, Gong-Ning

2014-08-01

287

Fundamental Plasma Processes in Saturn's Magnetosphere B.H. Mauk, D.C. Hamilton, T.W. Hill, G.B. Hospodarsky, R.E. Johnson, C. Paranicas, E. Roussos,  

E-print Network

.C. Sittler Jr. NASA Goddard Space Flight Center, Greenbelt, MD, USA R.M. Thorne Department of Atmospheric of fundamental processes that operate coherently across a broad spectrum of varying para- metric states-encompassing to space plasmas but represent the broad areas of recent stud- ies of Saturn's system. The first

Johnson, Robert E.

288

Fungal Diversity in Composting Process of Pig Manure and Mushroom Cultural Waste Based on Partial Sequence of Large Subunit rRNA  

Microsoft Academic Search

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

Hoon Kim; Sung Kyum Kim; Devaiah M Kambiranda; Young Han Lee; Jungho Kim; Han Dae Yun

2009-01-01

289

Processes Affecting Tropospheric Ozone Inferred from Ozonesonde and Other Tracer Data from the R/V R H Brown Atlantic Cruise (37N-34S) in January-February 1999  

NASA Technical Reports Server (NTRS)

During the Aerosols-99 trans-Atlantic cruise from Norfolk, VA, to Cape Town, South Africa, 22 ozonesondes were launched from the NOAA R/V R H Brown between 17 Jan and 6 Feb 1999, with all sondes but one reaching 30 km. A composite of ozone profiles along the transect shows high free tropospheric ozone (up to 100 ppbv at 9 km) between 5N and 20S, a coherent feature straddling either side of the ITCZ. Latitudinal variations of tropospheric ozone are interpreted using correlative measurements of surface ozone, CO, water vapor, and aerosol optical thickness (column absorbance) measured from the ship. Elevated ozone in the lower troposphere results from photochemical reactions of precursors emitted by biomass burning north of the ITCZ. However, the greatest ozone mixing ratios are in the mid-troposphere south of the ITCZ, which gives evidence of interhemispheric transport. Column-integrated tropospheric ozone, 35 DU from 0-16 km, agrees with that derived from the TOMS satellite by the modified-residual method [Thompson and Hudson, 1999]. NCEP wind fields, ship-launched radiosondes and back trajectories are consistent with a picture of recirculating air parcels centered in the tropical Atlantic region which is identified with the maximum wave-one amplitude in total ozone seen in sondes and by satellite.

Thompson, Anne M.; Doddridge, B. G.; Luke, W. T.; Johnson, J. E.; Witte, J. C.; Reynolds, R. M.; Johnson, B.; Oltmans, S. J.

1999-01-01

290

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...

291

VIRTUAL OBSERVATORY: Plate Content Digitization, Archive Mining & Image Sequence Processing edited by M. Tsvetkov, V. Golev, F. Murtagh, and R. Molina, Heron Press, Sofia, 2005  

E-print Network

VIRTUAL OBSERVATORY: Plate Content Digitization, Archive Mining & Image Sequence Processing edited and the panchromatic image. For instance, the Landsat 7 satellite (http://landsat.gsfc.nasa.gov/), equipped will use the term multispectral image reconstruction to refer to the joint processing of the multispectral

Granada, Universidad de

292

Tracking the interactions of rRNA processing proteins during nucleolar assembly in living Nicole Angelier,* Marc Tramier, Emilie Louvet,* Mat Coppey-Moisan, Tula M. Savino,*  

E-print Network

Reorganization of the nuclear machinery after mitosis is a fundamental but poorly understood process. Here we condense at the beginning of mitosis and re-assembled at the end of mitosis. During mitosis functions after mitosis, we chose to investigate the assembly of the nucleolar processing machinery in real

Paris-Sud XI, Université de

293

Intestinal Uptake of 6(R)-L-erythro-Tetrahydrobiopterin is Distinct from the Liver-Type MTX-Sensitive Accumulation Process  

Microsoft Academic Search

In order to increase the tissue level of tetrahydrobiopterin (BH4), supplementation with 6R-tetrahydrobiopterin (6RBH4) has been widely employed. In this work, the profile of BH4 accumulation was compared between the liver and the small intestine after feeding with 10mg\\/kg of 6RBH4 or 7,8-dihydrobiopterin (7,8BH2 ). Endogenous BH4 was 7.20 ± 0.28 and 1.59 ± 0.13 nmol\\/g in the liver and

Keiko Sawabe; Yasuko Suetake; Kazunori Osuke Wakasugi; Hiroyuki Hasegawa

294

Incorporation of ROH (R = CH3, C2H5, 2-C3H7) into (H2O)6(-): substituent effect on the growth process of the hydrogen-bond network.  

PubMed

The condensation reaction of water cluster anions, (H2O)n(-) + H2O ? (H2O)n+1(-), offers a prime opportunity to explore the growth process of the hydrogen-bond network involving molecular uptake and network rearrangement. Here, by exploiting an Ar-mediated approach, we investigate the association reaction of water hexamer anions, (H2O)6(-), with ROH (R = CH3, C2H5, 2-C3H7) by mass spectrometry combined with photoelectron spectroscopy. Quantitative analysis of the product mass spectra reveals that incorporation of ROH (R = CH3, C2H5) into (H2O)6(-) occurs with a cross section of the same size as in the (H2O)6(-) + D2O condensation, but with a slightly smaller cross section for R = 2-C3H7. Coexistence of two types of isomers, high electron-binding (type I) and low electron-binding (type II) forms, is observed in all the product ROH·(H2O)6(-) species by photoelectron spectroscopic measurement. These findings, in conjunction with ab initio study of MeOH·(H2O)6(-) structures, lead us to propose a molecular uptake mechanism at play in the incorporation of ROH into the (H2O)6(-) network. This also provides complementary information on the homogeneous condensation process of pure water cluster anions. PMID:24559050

Nakanishi, Ryuzo; Nagata, Takashi

2014-09-01

295

GPU computing and R  

E-print Network

Modern CPUs currently have 4 to 8 cores. In contrast an affordable GPU ( 200 euro) has 384 cores. This makes them ideally suited for parallel processing. Examples of problems that can benefit from processing on the GPU are Fast Fourier Transforms, the k-nearest neighbour algorithm or sequence alignment. If the problem can be cut into small pieces, it might be interesting to port it to the GPU. In order to make this compute power more accessible there a few options. One is to make some of the basic R functionality use the GPU directly, a second option is to wrap C(++) applications that make use of the GPU with R. Finally, we can build an interface between R and OpenCL, which leaves all possibilities open for the user and therefore provides maximum flexibility. In the first part of our presentation we will provide an overview of current R packages that use the GPU. In the second part, we will present our progress on the ROpenCL package. ROpenCL provides functions to transfer data frames to and from the GPU and to push kernel functions to the GPU, thereby unlocking the full potential of the GPU. These kernel functions still need to be written in OpenCL, however the interfacing with the GPU can all be done with R. The ROpenCL package is similar in spirit and based on the PyOpenCL

Openanalytics Bvba; Willem Ligtenberg

296

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

297

Q. J. R. Meteorol. Soc. (1999), 125, pp. 941965 The role of vertically varying cloud fraction in the parametrization of microphysical processes  

E-print Network

in the parametrization of microphysical processes in the ECMWF model By Christian Jakob1 and Stephen A. Klein2 1European. In this study, the microphysical impacts of vertically varying cloud fraction are addressed by developing a sub to the parametrization in the ECMWF model, the ability of the ECMWF model to account for the sub-grid nature of cloud

Jakob, Christian

298

Journal of Ceramic Processing Research. Vol. 15, No. 2, pp. 71~75 (2014) J O U R N A L O F  

E-print Network

of South Florida, Tampa FL 33620, USA Polyurethane foam was used as a precursor for fabricating Si foams from reticulated polyurethane substrates [1]. The process consists of dipping polyurethane foam in ceramic slurry, removing excess slurry, drying and pyrolyzing to remove the polyurethane foam

Volinsky, Alex A.

299

AN EXPERIMENTAL INVESTIGATION INTO THE EFFECT OF PROCESS CONDITIONS ON THE MASS CONCENTRATION OF CUTTING FLUID MIST IN TURNING. (R825370C057)  

EPA Science Inventory

Cutting fluid mists that are generated during machining processes represent a significant waste stream as well as a health hazard to humans. Epidemiological studies have shown a link between worker exposure to cutting fluid mist and an increase in respiratory ailments and seve...

300

[ital Z][prime], new fermions, and flavor-changing processes: Constraints on E[sub 6] models from [mu][r arrow][ital eee  

SciTech Connect

We study a new class of flavor-changing interactions, which can arise in models based on extended gauge groups (rank [gt]4) when new charged fermions are present together with a new neutral gauge boson. We discuss the cases in which the flavor-changing couplings in the new neutral current coupled to the [ital Z][prime] are theoretically expected to be large, implying that the observed suppression of neutral flavor-changing transitions must be provided by heavy [ital Z][prime] masses together with small [ital Z]-[ital Z][prime] mixing angles. Concentrating on E[sub 6] models, we show how the tight experimental limit on [mu][r arrow][ital eee] implies serious constraints on the [ital Z][prime] mass and mixing angle. We conclude that if the value of the flavor-changing parameters is assumed to lie in a theoretically natural range, in most cases the presence of a [ital Z][prime] much lighter than 1 TeV is unlikely.

Nardi, E. (Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109-1120 (United States))

1993-08-01

301

The Earth's magnetosphere is 165 R(sub E) long: Self-consistent currents, convection, magnetospheric structure, and processes for northward interplanetary magnetic field  

NASA Technical Reports Server (NTRS)

The subject of this paper is a self-consistent, magnetohydrodynamic numerical realization for the Earth's magnetosphere which is in a quasi-steady dynamic equilibrium for a due northward interplanetary magnetic field (IMF). Although a few hours of steady northward IMF are required for this asymptotic state to be set up, it should still be of considerable theoretical interest because it constitutes a 'ground state' for the solar wind-magnetosphere interaction. Moreover, particular features of this ground state magnetosphere should be observable even under less extreme solar wind conditions. Certain characteristics of this magnetosphere, namely, NBZ Birkeland currents, four-cell ionospheric convection, a relatively weak cross-polar potential, and a prominent flow boundary layer, are widely expected. Other characteristics, such as no open tail lobes, no Earth-connected magnetic flux beyond 155 R(sub E) downstream, magnetic merging in a closed topology at the cusps, and a 'tadpole' shaped magnetospheric boundary, might not be expected. In this paper, we will present the evidence for this unusual but interesting magnetospheric equilibrium. We will also discuss our present understanding of this singular state.

Fedder, J. A.; Lyon, J. G.

1995-01-01

302

The Homologous Putative GTPases Grn1p from Fission Yeast and the Human GNL3L Are Required for Growth and Play a Role in Processing of Nucleolar Pre-rRNAD?  

PubMed Central

Grn1p from fission yeast and GNL3L from human cells, two putative GTPases from the novel HSR1_MMR1 GTP-binding protein subfamily with circularly permuted G-motifs play a critical role in maintaining normal cell growth. Deletion of Grn1 resulted in a severe growth defect, a marked reduction in mature rRNA species with a concomitant accumulation of the 35S pre-rRNA transcript, and failure to export the ribosomal protein Rpl25a from the nucleolus. Deleting any of the Grn1p G-domain motifs resulted in a null phenotype and nuclear/nucleolar localization consistent with the lack of nucleolar export of preribosomes accompanied by a distortion of nucleolar structure. Heterologous expression of GNL3L in a ?grn1 mutant restored processing of 35S pre-rRNA, nuclear export of Rpl25a and cell growth to wild-type levels. Genetic complementation in yeast and siRNA knockdown in HeLa cells confirmed the homologous proteins Grn1p and GNL3L are required for growth. Failure of two similar HSR1_MMR1 putative nucleolar GTPases, Nucleostemin (NS), or the dose-dependent response of breast tumor autoantigen NGP-1, to rescue ?grn1 implied the highly specific roles of Grn1p or GNL3L in nucleolar events. Our analysis uncovers an important role for Grn1p/GNL3L within this unique group of nucleolar GTPases. PMID:16251348

Du, Xianming; Rao, Malireddi R.K. Subba; Chen, Xue Qin; Wu, Wei; Mahalingam, Sundarasamy; Balasundaram, David

2006-01-01

303

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

304

2007 Popper et Volume al. 8, Issue 12, Article R261 Open Access Research Gene-expression patterns reveal underlying biological processes in  

E-print Network

Gene Analysis expression expression programs of patterns in Kawasaki involving of gene disease neutrophil expression activation in peripheral and blood apoptosis. from children with Kawasaki disease revealed dynamic and variable gene Background: Kawasaki disease (KD) is an acute self-limited vasculitis and the leading cause of acquired heart disease in children in developed countries. No etiologic agent(s) has been identified, and the processes that mediate formation of coronary artery aneurysms and abatement of fever following treatment with intravenous immunoglobulin (IVIG) remain poorly understood. Results: In an initial survey, we used DNA microarrays to examine patterns of gene expression in peripheral whole blood from 20 children with KD; each was sampled during the acute, subacute, and convalescent phases of the illness. Acute KD was characterized by increased relative abundance of gene transcripts associated with innate immune and proinflammatory responses and decreased abundance of transcripts associated with natural killer cells and CD8 + lymphocytes.

Kawasaki Disease; Chisato Shimizu; Hiroko Shike; John T Kanegaye; Jane W Newburger; Robert P Sundel; Patrick O Brown; Jane C Burns; David A Relman

2007-01-01

305

Mathematical modelling and process optimization of a continuous 5-stage bioreactor cascade for production of poly[-(R)-3-hydroxybutyrate] by Cupriavidus necator.  

PubMed

A multistage system for poly(hydroxyalkanoate) (PHA) production consisting of five continuous stirred tank reactors in series (5-CSTR) with Cupriavidus necator DSM 545 as production strain was modelled using formal kinetic relations. Partially growth-associated production of PHA under nitrogen limited growth was chosen as modelling strategy, thus the Luedeking-Piret's model of partial growth-associated product synthesis was applied as working hypothesis. Specific growth rate relations adjusted for double substrate (C and N source) limited growth according to Megee et al. and Mankad-Bungay relation were tested. The first stage of the reactor cascade was modelled according to the principle of nutrient balanced continuous biomass production system, the second one as two substrate controlled process, while the three subsequent reactors were adjusted to produce PHB under continuous C source fed and nitrogen deficiency. Simulated results of production obtained by the applied mathematical models and computational optimization indicate that PHB productivity of the whole system could be significantly increased (from experimentally achieved 2.14 g L(-1) h(-1) to simulated 9.95 g L(-1) h(-1)) if certain experimental conditions would have been applied (overall dilution rate, C and N source feed concentration). Additionally, supplemental feeding strategy for switching from batch to continuous mode of cultivation was proposed to avoid substrate inhibition. PMID:23135491

Horvat, Predrag; Vrana Špoljari?, Ivna; Lopar, Markan; Atli?, Aid; Koller, Martin; Braunegg, Gerhart

2013-09-01

306

R & R in the Classroom.  

ERIC Educational Resources Information Center

Describes how an English teacher asks students to reflect and respond about their learning after each unit of instruction. Students in different classes planned a short story unit and a poetry unit. Cites students' writings. Despite the reluctance of students to write their reflections, the process is seen as a valuable component of the learning…

Combs, Barbara

1991-01-01

307

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

308

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...

309

Foundations and Trends R Signal Processing  

E-print Network

of Technology, Haifa 32000, Israel, yonina@ee.technion.ac.il Abstract One of the prime goals of statistical to be estimated are deterministic, a pop- ular approach is to bound the mean-squared error (MSE) achievable within param- eters. Statisticians use parameter estimation techniques to extract and infer scientific, medical

Eldar, Yonina

310

Intrusive [r] and Optimal Epenthetic Consonants  

ERIC Educational Resources Information Center

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

Uffmann, Christian

2007-01-01

311

STATISTICS 579 R Tutorial : Programming in R  

E-print Network

a value of the same shape as expr-1, containing elements from expr-1 or expr-2 depending on whether. A compound R expression consists of a group of simple R expressions enclosed in braces. Note that several R expressions may be entered on the same line as long as they are separated by semi-colons. Some examples are

312

Please cite this article in press as: Basile, B.M., Hampton, R.R., Monkeys show recognition without priming in a classification task. Behav. Process. (2012), http://dx.doi.org/10.1016/j.beproc.2012.08.005  

E-print Network

Please cite this article in press as: Basile, B.M., Hampton, R.R., Monkeys show recognition without Keywords: Implicit memory Nondeclarative memory Amnesia Repetition priming Categorization a b s t r a c for recognition presents a puzzle. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Seeing something

Hampton, Robert

313

Western Nanofabrication Facility Salam R. I. Gabran, Ph.D. candidate, supervisors; Prof. R. R. Mansour & Prof. M. M. A. Salama  

E-print Network

Western Nanofabrication Facility Salam R. I. Gabran, Ph.D. candidate, supervisors; Prof. R. R. Mansour & Prof. M. M. A. Salama Salam R. I. Gabran Center for Integrated RF Engineering, University resistance channel. The electrode fabrication process was optimized Optimized Intra-Cortical Electrode

Lennard, William N.

314

Process for functionalizing alkanes  

DOEpatents

Process for functionalizing saturated hydrocarbons comprises: (a) reacting said saturated hydrocarbons of the formula: R[sub 1]H wherein H represents a hydrogen atom; and R[sub 1] represents a saturated hydrocarbon radical, with a metal complex of the formula: CpRh[P(R[sub 2])[sub 3

Bergman, R.G.; Janowicz, A.H.; Periana, R.A.

1988-05-24

315

[51] R. Sun, L. Bookman, and S. Shekhar, (eds.) The Working Notes of the AAAI Workshop on Integrating Neural and Symbolic Processes, American Association for Artificial Intelligence, Menlo Park, CA. 1992  

E-print Network

. 1992 [52] R. Sun and D. Waltz, Neural networks and human intelligence, Journal of Mathematical Psychology, Vol.34, No.4, 483�488 1990. [53] R. Sun and D. Waltz, Neurally Inspired Massively Parallel Model, NY. 1989. [59] D. Waltz, Connectionist models: not just a notational variant, not a panacea. in: D

Varela, Carlos

316

17.1. M R -, M R I R,  

E-print Network

M . Io R I Io, Io = R, Q.E.D. 17.4. k . : , k , char(k) = p k p. k, . . . , an , - g(y1, . . . , ym) k[y1, . . . , ym] g(a1, . . . , am) = 0 0 k[y1, . . . , ym], m + 1 i n, . . . , ft, g1, . . . , gt #12;17. 17: 89 k[x1, . . . , xn], gi(a1, . . . am) = 0 Lo 1 i m Lo

Kasparian, Azniv

317

R2WinBUGS: A Package for Running WinBUGS from R  

Microsoft Academic Search

The R2WinBUGS package provides convenient functions to call WinBUGS from R. It automatically writes the data and scripts in a format readable by WinBUGS for processing in batch mode, which is possible since version 1.4. After the WinBUGS process has finished, it is possible either to read the resulting data into R by the package itself--which gives a compact graphical

Sibylle Sturtz; Uwe Ligges; Andrew Gelman

2005-01-01

318

e n g e n i o u s w i n t e r 2 0 0 3 1 A transistor in a given process technology is usually characterized by its unity-gain frequency shown as fT . This is the frequency at which the cur-  

E-print Network

e n g e n i o u s w i n t e r 2 0 0 3 1 A transistor in a given process technology is usually ratio of the output current to input current) of a transistor drops to unity. While the unity-gain frequency of a transistor provides an approximate measure to compare transistors in different technologies

319

Dr. John R. Dorgan Faculty Trustee  

E-print Network

Dr. John R. Dorgan Faculty Trustee John R. Dorgan is currently Professor of Chemical Energy Laboratory. Professor Dorgan feels that ecological concerns are a predominant research motivator nanocomposites which are based on renewable resources as well as on new process technologies for biorefining

320

Control in Act-R and Soar  

Microsoft Academic Search

This paper compares the Act-R and Soar cognitive architec- tures, focusing on their theories of control. Act-R treats con- trol (conflict resolution) as an automatic process, whereas Soar treats it as a potentially deliberate, knowledge-based process. The comparison reveals that Soar can model ex- tremely flexible control, but has difficulty accounting for probabilistic operator selection and the independent effects of

Todd R. Johnson

1997-01-01

321

Chiral inversion of R(-) fenoprofen and ketoprofen enantiomers in cats.  

PubMed

The chiral inversion process is a characteristic metabolic pathway for different aryl-2-propionic acids or profens. Important variations have been observed between these individual compounds as well as between animal species. In this study, R(-) fenoprofen [R(-)FPF] and R(-) ketoprofen [R(-) KTF] were used to investigate their comparative stereoconversion in cats. After intravenous (i.v.) administration of R(-) FPF, the percentage of chiral inversion was 93.20+/-13.70%. A highly significant correlation (r: 0.978) was observed between the clearance of R(-) FPF and the chiral inversion process. After i.v. administration of R(-) KTF, the percentage of inversion was only 36.73+/-2.8%. No correlation between the clearance of R(-) KTF and this process was observed. R(-) FPF was metabolized by the pathways of thioesterification - chiral inversion processes. For R(-) KTF, the competitive metabolic pathways, glucuronidation and hydroxylation may be involved. However, these metabolic steps are saturable or less functional in cats. Moreover, the thioesterification of R(-) KTF in in vitro studies has been shown to be important in carnivores. The lack of correlation between clearance and chiral inversion process of R(-) KTF may be finally explained by deviation of thioesterification to other metabolic pathways of lipids and/or aminoacid conjugation, particulary glicine derivatives. PMID:11106999

Castro, E; Soraci, A; Fogel, F; Tapia, O

2000-10-01

322

77 FR 1656 - Proposed Establishment of Restricted Areas R-5402, R-5403A, R-5403B, R-5403C, R-5403D, R-5403E, R...  

Federal Register 2010, 2011, 2012, 2013

...R-5403D, R-5403E, R-5403F; Devils Lake, ND AGENCY: Federal Aviation Administration...establish restricted area airspace within the Devils Lake East Military Operations Area (MOA...Camp Grafton Range, in the vicinity of Devils Lake, ND. This extension is a...

2012-01-11

323

A Conceptual Framework & Monitoring System for Rangeland Ecosystem Goods, Services & Processes Adaptive Management Cycle. Adapted from Williams, B. K., R. C. Szaro, and C. D. Shapiro. 2007. Adaptive Management: The U.S.  

E-print Network

, made available to humans through human activities beginning with extraction. Once outputs enter to yield value to humans. Social and economic processes needed for extraction and subsequent processing. Core ecological processes are the fundamental processes that occur in ecosystems through which life

Wyoming, University of

324

Expression of genes for AhR and Nrf2 signal pathways in the retina of OXYS rats during the development of retinopathy and melatonin-induced changes in this process.  

PubMed

Modulation of oxidative stress is one of the experimental approaches to the therapy of age-related macular degeneration. Melatonin holds much promise in this respect. It was hypothesized that the efficiency of melatonin in age-related macular degeneration is associated with its ability to modulate gene expression for the AhR and Nrf2 signal pathways. Experiments were performed on premature aging OXYS rats, which serve as a reliable model of age-related macular degeneration in humans. We studied the effect of melatonin on gene mRNA for the AhR and Nrf2 signal pathways. Melatonin was shown to decrease the level of mRNA for AhR-dependent genes of CYP1A2 and CYP1B1 cytochromes in the retina, but had no effect on the content of mRNA for Nrf2-dependent genes in OXYS rats. PMID:25110076

Perepechaeva, M L; Stefanova, N A; Grishanova, A Yu

2014-08-01

325

R E S E A R C H A R T I C L E Arbuscular mycorrhizal symbiosis can counterbalance the negative  

E-print Network

R E S E A R C H A R T I C L E Arbuscular mycorrhizal symbiosis can counterbalance the negative in-6941.2007.00363.x Editor: Karl Ritz Keywords AM symbiosis; plant diversity; catabolic diversity; Eucalyptus. These results highlight the role of AM symbiosis in the processes involved in soil bio-functioning and plant

Thioulouse, Jean

326

DNA Microarrays An R Tutorial  

E-print Network

DNA Microarrays An R Tutorial Gene Expression Analysis & R Tutorial Weigang Qiu Department Expression Analysis & R Tutorial #12;DNA Microarrays An R Tutorial Outline 1 DNA Microarrays 2 An R Tutorial Weigang Qiu Gene Expression Analysis & R Tutorial #12;DNA Microarrays An R Tutorial Functional Genomics

Qiu, Weigang

327

1,2-dichlorohexafluoro-cyclobutane (1,2-c-C4F6Cl2, R-316c) a Potent Ozone Depleting Substance and Greenhouse Gas: Atmospheric Loss Processes, Lifetimes, and Ozone Depletion and Global Warming Potentials for the (E)- and (Z)- Stereoisomers  

NASA Astrophysics Data System (ADS)

1,2-dichlorohexafluoro-cyclobutane (1,2-c-C4F6Cl2, R-316c) is currently used in medical applications, as inhaled non-immobilizer amnesiac, in limited quantities and has recently been considered as a potential chlorofluoro/hydrofluoro-carbon replacement compound. R-316c usage is not restricted under the Montreal Protocol, although, R-316c represents a potent ozone depleting substance and greenhouse gas. In this work, a combination of laboratory studies of infrared absorption spectra, kinetic, and photolysis processes were performed for the (E)- and (Z)- stereoisomers of R-316c to enable an evaluation of their atmospheric lifetimes, ozone depletion (ODPs) and global warming potentials (GWPs). More specifically, O(1D), OH, and O3 reaction rate coefficients, as well as UV absorption spectra, including temperature dependence, and photolysis quantum yields and stable photolysis end-products were determined. The results from these studies will be presented. R-316c lifetimes and ODPs were evaluated using a 2-D atmospheric chemical model. Both isomers of R-316c were shown to be long-lived substances, primarily removed in the stratosphere by UV photolysis, with large ODPs, >0.3. A line-by-line radiative transfer model was used to calculate radiative efficiencies and, thus, GWPs. The GWPs for both isomers are substantial, ~5000 on the 100-year time horizon. In this presentation, we highlight the need for a thorough evaluation of the atmospheric processing of proposed replacement substances prior to usage and their inevitable emission into the atmosphere. The results of such studies enable policy makers to make informed decisions.

Papadimitriou, V. C.; McGillen, M. R.; Smith, S. C.; Jubb, A. M.; Portmann, R. W.; Hall, B. D.; Fleming, E. L.; Jackman, C. H.; Burkholder, J. B.

2013-12-01

328

6.8 Cylinder Liner Boring Case Study Demonstrating the Process of SPC The following case study demonstrates the application of X and R control charts to the study of  

E-print Network

demonstrates the application of X and R control charts to the study of a manufacturing operation. As will be seen, the case study uses control charts to identify the presence of faults within a cylinder boring cost/productivity. The first action taken by the team was to construct a flow chart of the cylinder

Di Bucchianico, Alessandro

329

1,2-Dichlorohexafluoro-Cyclobutane (1,2-c-C4F6Cl2, R-316c) a Potent Ozone Depleting Substance and Greenhouse Gas: Atmospheric Loss Processes, Lifetimes, and Ozone Depletion and Global Warming Potentials for the (E) and (Z) stereoisomers  

NASA Technical Reports Server (NTRS)

The atmospheric processing of (E)- and (Z)-1,2-dichlorohexafluorocyclobutane (1,2-c-C4F6Cl2, R-316c) was examined in this work as the ozone depleting (ODP) and global warming (GWP) potentials of this proposed replacement compound are presently unknown. The predominant atmospheric loss processes and infrared absorption spectra of the R-316c isomers were measured to provide a basis to evaluate their atmospheric lifetimes and, thus, ODPs and GWPs. UV absorption spectra were measured between 184.95 to 230 nm at temperatures between 214 and 296 K and a parametrization for use in atmospheric modeling is presented. The Cl atom quantum yield in the 193 nm photolysis of R- 316c was measured to be 1.90 +/- 0.27. Hexafluorocyclobutene (c-C4F6) was determined to be a photolysis co-product with molar yields of 0.7 and 1.0 (+/-10%) for (E)- and (Z)-R-316c, respectively. The 296 K total rate coefficient for the O(1D) + R-316c reaction, i.e., O(1D) loss, was measured to be (1.56 +/- 0.11) × 10(exp -10)cu cm/ molecule/s and the reactive rate coefficient, i.e., R-316c loss, was measured to be (1.36 +/- 0.20) × 10(exp -10)cu cm/molecule/s corresponding to a approx. 88% reactive yield. Rate coefficient upper-limits for the OH and O3 reaction with R-316c were determined to be <2.3 × 10(exp -17) and <2.0 × 10(exp -22)cu cm/molecule/s, respectively, at 296 K. The quoted uncertainty limits are 2(sigma) and include estimated systematic errors. Local and global annually averaged lifetimes for the (E)- and (Z)-R-316c isomers were calculated using a 2-D atmospheric model to be 74.6 +/- 3 and 114.1 +/-10 years, respectively, where the estimated uncertainties are due solely to the uncertainty in the UV absorption spectra. Stratospheric photolysis is the predominant atmospheric loss process for both isomers with the O(1D) reaction making a minor, approx. 2% for the (E) isomer and 7% for the (Z) isomer, contribution to the total atmospheric loss. Ozone depletion potentials for (E)- and (Z)-R-316c were calculated using the 2-D model to be 0.46 and 0.54, respectively. Infrared absorption spectra for (E)- and (Z)-R-316c were measured at 296 K and used to estimate their radiative efficiencies (REs) and GWPs; 100-year time-horizon GWPs of 4160 and 5400 were obtained for (E)- and (Z)-R-316c, respectively. Both isomers of R-316c are shown in this work to be long-lived ozone depleting substances and potent greenhouse gases.

Papadimitriou, Vassileios C.; McGillen, Max R.; Smith, Shona C.; Jubb, Aaron M.; Portmann, Robert W.; Hall, Bradley D.; Fleming, Eric L.; Jackman, Charles H.; Burkholder, James B.

2013-01-01

330

Genome-wide identification and characterization of R2R3MYB family in Solanum lycopersicum.  

PubMed

The R2R3MYB proteins comprise one of the largest families of transcription factors and play regulatory roles in developmental processes and defense responses in plants. However, there has been relatively little effort to systematically carry out comprehensive genomic and functional analyses of these genes in tomato (Solanum lycopersicum L.), a reference species for Solanaceae plants, and the model plant for fruit development. In this study, a total of 121 R2R3MYB genes were identified in the tomato genome released recently and further classified into 29 subgroups based on the phylogenetic analysis of the complete protein sequences. Phylogenetic comparison of the members of this superfamily among tomato, Arabidopsis, grape, rice, poplar, soybean, cucumber and apple revealed that the putative functions of some tomato R2R3MYB proteins were clustered into the Arabidopsis functional clades. The chromosome distribution pattern revealed that tomato R2R3MYB genes were enriched on several chromosomes and 52 % of the family members were tandemly duplicated genes. Tissue specificity or different expression levels of SlR2R3MYBs in different tissues suggested differential regulation of tissue development as well as metabolic regulation. The transcript abundance level analysis during abiotic conditions identified a group of R2R3MYB genes that responded to one or more treatments suggesting that the SlR2R3MYBs played major roles in the plant response to abiotic conditions and involved in signal transduction pathways. This study not only provides a solid foundation for further functional dissection of tomato R2R3MYB family genes, but may also be profitable for, in the future, the improvement of tomato stress tolerance and fruit quality. PMID:25005853

Zhao, Panpan; Li, Qiang; Li, Jing; Wang, Lina; Ren, Zhonghai

2014-12-01

331

EPSCoR Research Infrastructure Improvement Grant Program  

NSF Publications Database

... Program to Stimulate Competitive Research (EPSCoR) is a program designed to fulfill the National ... Requirements Proposal Review Information NSF Proposal Review Process Review Protocol and Associated ...

332

DC/AC Student Guide: R2R Ladder Network  

NSDL National Science Digital Library

R2R Ladder Networks provide a simple and inexpensive method of converting digital information to an analog signal. The R2R ladder circuit is a very common piece of almost all Digital-to-Analog converters.  By understanding how the R2R ladder system works, a better understanding of Digital-to-Analog converters can be had.

Casas, Jesus

2014-07-29

333

r Human Brain Mapping 000:000000 (2011) r Speech Perception in the Child Brain: Cortical  

E-print Network

r Human Brain Mapping 000:000�000 (2011) r Speech Perception in the Child Brain: Cortical Timing brain is modified early in child development to optimally process incoming speech sounds of native Pekka Niemi,3,4 and Riitta Salmelin1 1 Brain Research Unit, Low Temperature Laboratory, Aalto University

Allen, Jont

334

Hartwig Hen Lauderdale R  

E-print Network

_____________ UR 3520 ­ STRUCTOR: Hartwig Hen Lauderdale R ONE/VOICE MAIL: hhhoch ACHING ASS am Benjamin Lauderdale ducation Cen 577-6378 u Thu: 10:40a- ass: 04/24/12 ERIALS: tment Compu for each sess dologies for a horough For each ass r 24 hours wil d

Slatton, Clint

335

Interfacing R Thomas Lumley  

E-print Network

;Examples · WinBUGS implements Bayesian analyse; it's not super-fast but is very flexible · It needs special (& clever) architecture to achieve this · WinBUGS' input, output, graphics are all rather clunky · R is better; so R2WinBUGS calls WinBUGS for the difficult bits, and does all the `translation' itself

Rice, Ken

336

ALSFRS-R.  

PubMed

The ALSFRS-R is an attractive primary outcome measure in clinical trials of ALS because it is validated, easy to administer, minimizes dropout, reduces cost, and correlates with survival. Unlike the other standard outcome measures currently employed, the ALSFRS-R is also a measure of global function. PMID:15512883

Gordon, Paul H; Miller, Robert G; Moore, Dan H

2004-09-01

337

Kenneth R. Robertson, Ph.D., Plant Systematist,  

E-print Network

in identifying plants. r Successfully use a dichotomous key. r Describe plant processes: photosynthesis from crops is only one of the many plant products useful to people. What plants provide can be summedCHAPTER 4 Botany Botany 4- Botany Kenneth R. Robertson, Ph.D., Plant Systematist, Illinois Natural

Downie, Stephen R.

338

Unconscious Priming According to Multiple S-R Rules  

ERIC Educational Resources Information Center

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

Kiesel, Andrea; Kunde, Wilfried; Hoffmann, Joachim

2007-01-01

339

R&D Performance in Chinese industry  

Microsoft Academic Search

This research, which investigates a set of fundamental relationships in the R&D literature, is based on an unusually rich set of panel data covering the population of China’s large and medium-size manufacturing enterprises. Using a recursive three-equation system, we investigate the determinants of firm-level R&D intensity, the process of knowledge production, and the impact of innovation on firm performance. Several

Gary H. Jefferson; Bai Huamao; Guan Xiaojing; Yu Xiaoyun

2006-01-01

340

R Tricks for Kids  

ERIC Educational Resources Information Center

Real-world phenomena simulation models, which can be used to engage middle-school students with probability, are described. Links to R instructional material and easy-to-use code are provided to facilitate implementation in the classroom.

Braun, W. John; White, Bethany J. G.; Craig, Gavin

2014-01-01

341

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

NASA Astrophysics Data System (ADS)

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 may be used to calculate the thermodynamic properties of mixtures, including dew and bubble point properties, within the experimental uncertainties of the available measured properties. It incorporates the most accurate equations of state available for each pure fluid. The estimated uncertainties of calculated properties are 0.1% in density and 0.5% in heat capacities and in the speed of sound. Calculated bubble point pressures have typical uncertainties of 0.5%.

Lemmon, Eric W.; Jacobsen, Richard T.

2004-06-01

342

The Ratio R{sub dp} of the quasielastic nd {yields} p(nn) to the elastic np {yields} pn charge-exchange-process yields at the proton emitting angle {theta}{sub p,lab} = 0 deg. over 0.55-2.0 GeV neutron-beam energy region. Comparison of the results with the model-dependent calculations  

SciTech Connect

Our new experimental results (see, e.g., Preprint JINR no. E1-2008-61 (Dubna, 2008)) on ratio R{sub dp} of the quasielastic charge-exchange yield at the proton emitting angle {theta}{sub p,lab} = 0 deg. for the nd {yields} p(nn) reaction to the elastic np {yields} pn charge-exchange yield were presented. The measurements were carried out at the Nuclotron of the Veksler and Baldin Laboratory of High Energies of the JINR (Dubna) at the neutron-beam kinetic energies of 0.55, 0.8, 1.0, 1.2, 1.4, 1.8, and 2.0 GeV. In this paper the comparison of the experimental R{sub dp} data with the obtained R{sub dp} calculations within the impulse approximation by using the invariant-amplitude sets from the GW/VPI phase-shift analysis is made. The R{sub dp} values calculated using the set of invariant amplitude data for the elastic np {yields} pn charge exchange at {theta}{sub p,CM} = 0 deg., agree with the experimental data. This confirmed the nd {yields} p(nn) process yield at {theta}{sub p,CM} = 0 deg. is caused by the contribution of the spin-dependent part of the elastic np {yields} pn charge-exchange reaction. Thus, it has been shown that the obtained experimental R{sub dp} results can be used for the Delta-Sigma experimental program to reduce the total ambiguity in the extraction of the amplitude real parts.

Sharov, V. I., E-mail: sharov@sunhe.jinr.ru; Morozov, A. A.; Shindin, R. A.; Chernykh, E. V.; Nomofilov, A. A.; Strunov, L. N. [Joint Institute for Nuclear Research (Russian Federation)

2009-06-15

343

R for Statistics Rafal Kulik  

E-print Network

R for Statistics Rafal Kulik Department of Mathematics and Statistics University of Ottawa Statistical Society of Ottawa 23 September 2011 Rafal Kulik #12;R for Statistics SSO meeting Plan Rafal Kulik 1 #12;R for Statistics SSO meeting Plan What is R? Rafal Kulik 1 #12;R for Statistics SSO meeting

Kulik, Rafal

344

R -matrix treatment of high-energy electron-impact excitation processes: The generalized oscillator strengths for the Na 3s-3p and 2p-3s transitions  

NASA Astrophysics Data System (ADS)

High-energy electron-impact excitation cross sections are directly proportional to the generalized oscillator strengths (GOS’s) of the target (an atom or molecule). In the present work, the GOS’s for the Na 3s-3p and 2p-3s transitions are calculated by using the updated R -matrix codes. The present results for the 3s-3p transition are in good agreement with the experimental measurements at 1keV incident energy. For the 2p-3s resonance transition, the present results are larger than the measurements at 1keV incident energy. The difference is discussed. The important role of the inner shell electron correlations is elucidated. The positions of the first and second GOS minimums and maximums for these two transitions are reported. The dependence of the GOS minimum and maximum positions on the increasing incident energies are discussed.

Han, Xiaoying; Li, Yueming; Zhang, Hong; Yan, Jun; Li, Jiaming; Voky, Lan

2008-11-01

345

miR-25 and miR-92a regulate insulin I biosynthesis in rats  

PubMed Central

The 3? UTR of insulin has been identified as a critical region that confers mRNA stability, which is crucial for promoting transcription in response to glucose challenge. miRNAs are endogenously encoded non-coding RNAs that function as regulators of gene expression. This regulatory function is generally mediated by complementary binding to the 3?UTR of its mRNA targets that affects subsequent translational process. Genes involved in the regulation of glucose homeostasis, particularly in insulin production, have been found as targets of several miRNAs. Yet, no direct miRNA-based regulators of insulin biosynthesis have been identified. In this study, identification of possible miRNA-based regulators of insulin production is explored. Members of a miRNA family, miR-25 and miR-92a, are found as direct modulators of insulin expression. Overexpression of miR-25 or miR-92a reduced insulin expression while inhibition of miR-25 and miR-92a expression using corresponding antagomiRs promoted insulin expression and ultimately enhanced glucose-induced insulin secretion. Furthermore, suppression of insulin secretion by pre miR-9 could be attenuated by treatment with anti-miR-25 or miR-92a. Interestingly, we found the binding site of miR-25 and miR-92a to overlap with that of PTBP1, an important RNA binding molecule that stabilizes insulin mRNA for translation. Despite the increase in PTBP1 protein in the pancreas of diabetic rats, we observed insulin expression to be reduced alongside upregulation of miR-25 and miR-92a, suggesting an intricate regulation of insulin (bio)synthesis at its mRNA level. PMID:24084692

Setyowati Karolina, Dwi; Sepramaniam, Sugunavathi; Tan, Hui Zhing; Armugam, Arunmozhiarasi; Jeyaseelan, Kandiah

2013-01-01

346

Systems factorial technology with R.  

PubMed

Systems factorial technology (SFT) comprises a set of powerful nonparametric models and measures, together with a theory-driven experiment methodology termed the double factorial paradigm (DFP), for assessing the cognitive information-processing mechanisms supporting the processing of multiple sources of information in a given task (Townsend and Nozawa, Journal of Mathematical Psychology 39:321-360, 1995). We provide an overview of the model-based measures of SFT, together with a tutorial on designing a DFP experiment to take advantage of all SFT measures in a single experiment. Illustrative examples are given to highlight the breadth of applicability of these techniques across psychology. We further introduce and demonstrate a new package for performing SFT analyses using R for statistical computing. PMID:24019062

Houpt, Joseph W; Blaha, Leslie M; McIntire, John P; Havig, Paul R; Townsend, James T

2014-06-01

347

Quantum information processing using frequency control of impurity spins in diamond A. M. Zagoskin,1,2 J. R. Johansson,2 S. Ashhab,2 and Franco Nori2,3  

E-print Network

a universal two-qubit gate CPHASE . rf and optical control together promise a scalable quantum computing Impurity spins in diamond are among the most promising candidates for solid-state quantum hardware. The soQuantum information processing using frequency control of impurity spins in diamond A. M. Zagoskin

Nori, Franco

348

Please cite this article in press as: Bourne, G.R., et al., Closed channel fabrication using micromolding of metallic glass. J. Mater. Process. Tech. (2009), doi:10.1016/j.jmatprotec.2008.12.003  

E-print Network

IN PRESSG Model PROTEC-12488; No.of Pages 4 Journal of Materials Processing Technology xxx (2009) xxx­xxx Accepted 7 December 2008 Available online xxx Keywords: Micromolding Metallic glass Amorphous metal Net material. The sacrificial silicon molds were created using standard lithographic and deep reactive ion

Sawyer, Wallace

349

Monsoons: Processes, predictability, and the prospects for P. J. Webster1, V. O. Magana2, T. N. Palmer3, J. Shukla4, R. A. Tomas1, M. Yanai5, and T. Yasunari6  

E-print Network

Monsoons: Processes, predictability, and the prospects for prediction P. J. Webster1, V. O. Magana2 planetary heat sources and sinks, and interactions between them. The Asian-Australian monsoon system, which timescales is a major focus of GOALS. Empirical seasonal forecasts of the monsoon have been made

Webster, Peter J.

350

Counting process Poisson process  

E-print Network

, 2008 ­ p. 9/1 #12;Compound Poisson Process · Let {N(t)} be a Poisson process with rate · Let Yk(t) = N(t) i=1 Yi · Then {S(t)} is called a compound Poisson process · {S(t)} has stationaryLast Time · Counting process · Poisson process · Equivalent definitions Today's lecture: Sections 6

Ross, Kevin

351

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

352

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

353

Strong and weak gravitational field in $R+?^4/R$ gravity  

E-print Network

We introduce a new approach for investigating the weak field limit of vacuum field equations in $f(R)$ gravity and we find the weak field limit of $f(R)=R+\\mu ^4/R$ gravity. Furthermore, we study the strong gravity regime in $R+\\mu^{4}/R$ model of $f(R)$ gravity. We show the existence of strong gravitational field in vacuum for such model. We find out in the limit $\\mu\\rightarrow 0$, the weak field limit and the strong gravitational field can be regarded as a perturbed Schwarzschild metric.

Kh. Saaidi; A. Vajdi; S. W. Rabiei; A. Aghamohammadi; H. Sheikhahmadi

2010-01-25

354

Dr. William R. Lucas  

NASA Technical Reports Server (NTRS)

Dr. William R. Lucas served as Marshall Space Flight Center Director from June 15, 1974 until July 3, 1986, when he retired after thirty-four years of civil service. Prior to the appointment, Lucas served as Center Deputy Director (1971-1974), Program Development Director (1968-1971), Astronautics Laboratory Director (1966-1968), and Propulsion and Vehicle Laboratory Director (1960-1966).

1984-01-01

355

Introduccin R: lenguaje  

E-print Network

. ESS, Emacs Programación estadística con R Ramón Díaz-Uriarte Bioinformatics Unit Centro Nacional de://ligarto.org/rdiaz Copyright © 2006 Ramón Díaz-Uriarte Instituto Español de Oceanografía, Santander, Abril 2006 (1 : 263) #12

Díaz-Uriarte, Ramón

356

R. Burl Yarberry  

ERIC Educational Resources Information Center

R. Burl Yarberry was born in 1920 in Pueblo, Colorado. He attended public schools in Pueblo and graduated from high school in 1938. After a year attending the Colorado School of Mines, he enlisted in the U.S. Marine Corps and served in the Pacific during World War II. Following his discharge, he earned a BA in English from Western State College of…

Nishimoto, Warren

2007-01-01

357

Simulation Insights Using "R"  

ERIC Educational Resources Information Center

This article attempts to introduce the reader to computational thinking and solving problems involving randomness. The main technique being employed is the Monte Carlo method, using the freely available software "R for Statistical Computing." The author illustrates the computer simulation approach by focusing on several problems of…

Kostadinov, Boyan

2013-01-01

358

R0 Cosmology ?  

E-print Network

It is postulated that the action of the FRW-universe is the cosmological term of Einsteins theory (no curvature term - R0 Cosmology). The expansion equation emerging from the embedding of this most simple brane world with variable speed of light is deduced. The universal dimensionless coupling constant of gravity is addressed. Some implications on the deep problems of cosmology are discussed.

Gerald Vones

2001-05-21

359

R&D 100 Entry Submitting Organization  

E-print Network

like sputter deposition and chemical vapor deposition (CVD), which require high temperature and/or high: (817) 762-6911 earl.w.stromberg@lmco.com Product Name Multifunctional Optical Coatings by Rapid Self-Assembly #12;3 R&D 100 Entry Brief Description This simple, safe, and economical coating process enables

360

Learning and Memory Eric R. Kandel  

E-print Network

Back 62 Learning and Memory Eric R. Kandel Irving Kupfermann Susan Iversen BEHAVIOR IS THE RESULT the environment alters behavior are learning and memory. Learning is the process by which we acquire knowledge retrieved. Many important behaviors are learned. Indeed, we are who we are largely because of what we learn

Ulanovsky, Nachum

361

Networks and globalization policies Douglas R. White  

E-print Network

9 Networks and globalization policies Douglas R. White 1 This Chapter argues for connecting models of several kinds of macro- and micro-processes as they affect structure and dynamics in the globalization and to loosen assumptions about determinacy in models of networks and globalization. As do many models

White, Douglas R.

362

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

PubMed

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

Björkroth, K J; Korkeala, H J

1997-02-01

363

TGF?R2 is a major target of miR-93 in nasopharyngeal carcinoma aggressiveness  

PubMed Central

Background MiR-17-92 cluster and its paralogues have emerged as crucial regulators of many oncogenes and tumor suppressors. Transforming growth factor-? receptor II (TGF?R2), as an important tumor suppressor, is involved in various cancer types. However, it is in cancer that only two miRNAs of this cluster and its paralogues have been reported so far to regulate TGF?R2. MiR-93 is oncogenic, but its targetome in cancer has not been fully defined. The role of miR-93 in nasopharyngeal carcinoma (NPC) still remains largely unknown. Methods We firstly evaluated the clinical signature of TGF?R2 down-regulation in clinical samples, and next used a miRNA expression profiling analysis followed by multi-validations, including Luciferase reporter assay, to identify miRNAs targeting TGF?R2 in NPC. In vitro and in vivo studies were performed to further investigate the effects of miRNA-mediated TGF?R2 down-regulation on NPC aggressiveness. Finally, mechanism studies were conducted to explore the associated pathway and genes influenced by this miRNA-mediated TGF?R2 down-regulation. Results TGF?R2 was down-regulated in more than 50% of NPC patients. It is an unfavorable prognosis factor contributing to clinical NPC aggressiveness. A cluster set of 4 TGF?R2-associated miRNAs was identified; they are all from miR-17-92 cluster and its paralogues, of which miR-93 was one of the most significant miRNAs, directly targeting TGF?R2, promoting cell proliferation, invasion and metastasis in vitro and in vivo. Moreover, miR-93 resulted in the attenuation of Smad-dependent TGF-? signaling and the activation of PI3K/Akt pathway by suppressing TGF?R2, further promoting NPC cell uncontrolled growth, invasion, metastasis and EMT-like process. Impressively, the knockdown of TGF?R2 by siRNA displayed a consentaneous phenocopy with the effect of miR-93 in NPC cells, supporting TGF?R2 is a major target of miR-93. Our findings were also substantiated by investigation of the clinical signatures of miR-93 and TGF?R2 in NPC. Conclusion The present study reports an involvement of miR-93-mediated TGF?R2 down-regulation in NPC aggressiveness, thus giving extended insights into molecular mechanisms underlying cancer aggressiveness. Approaches aimed at blocking miR-93 may serve as a promising therapeutic strategy for treating NPC patients. PMID:24606633

2014-01-01

364

r-Java 2.0: the nuclear physics  

E-print Network

[Aims:] We present r-Java 2.0, a nucleosynthesis code for open use that performs r-process calculations as well as a suite of other analysis tools. [Methods:] Equipped with a straightforward graphical user interface, r-Java 2.0 is capable of; simulating nuclear statistical equilibrium (NSE), calculating r-process abundances for a wide range of input parameters and astrophysical environments, computing the mass fragmentation from neutron-induced fission as well as the study of individual nucleosynthesis processes. [Results:] In this paper we discuss enhancements made to this version of r-Java, paramount of which is the ability to solve the full reaction network. The sophisticated fission methodology incorporated into r-Java 2.0 which includes three fission channels (beta-delayed, neutron-induced and spontaneous fission) as well as computation of the mass fragmentation is compared to the upper limit on mass fission approximation. The effects of including beta-delayed neutron emission on r-process yield is studied. The role of coulomb interactions in NSE abundances is shown to be significant, supporting previous findings. A comparative analysis was undertaken during the development of r-Java 2.0 whereby we reproduced the results found in literature from three other r-process codes. This code is capable of simulating the physical environment of; the high-entropy wind around a proto-neutron star, the ejecta from a neutron star merger or the relativistic ejecta from a quark nova. As well the users of r-Java 2.0 are given the freedom to define a custom environment. This software provides an even platform for comparison of different proposed r-process sites and is available for download from the website of the Quark-Nova Project: http://quarknova.ucalgary.ca/

M. Kostka; N. Koning; Z. Shand; R. Ouyed; P. Jaikumar

2014-02-16

365

The r-Java 2.0 code: nuclear physics  

NASA Astrophysics Data System (ADS)

Aims: We present r-Java 2.0, a nucleosynthesis code for open use that performs r-process calculations, along with a suite of other analysis tools. Methods: Equipped with a straightforward graphical user interface, r-Java 2.0 is capable of simulating nuclear statistical equilibrium (NSE), calculating r-process abundances for a wide range of input parameters and astrophysical environments, computing the mass fragmentation from neutron-induced fission and studying individual nucleosynthesis processes. Results: In this paper we discuss enhancements to this version of r-Java, especially the ability to solve the full reaction network. The sophisticated fission methodology incorporated in r-Java 2.0 that includes three fission channels (beta-delayed, neutron-induced, and spontaneous fission), along with computation of the mass fragmentation, is compared to the upper limit on mass fission approximation. The effects of including beta-delayed neutron emission on r-process yield is studied. The role of Coulomb interactions in NSE abundances is shown to be significant, supporting previous findings. A comparative analysis was undertaken during the development of r-Java 2.0 whereby we reproduced the results found in the literature from three other r-process codes. This code is capable of simulating the physical environment of the high-entropy wind around a proto-neutron star, the ejecta from a neutron star merger, or the relativistic ejecta from a quark nova. Likewise the users of r-Java 2.0 are given the freedom to define a custom environment. This software provides a platform for comparing proposed r-process sites.

Kostka, M.; Koning, N.; Shand, Z.; Ouyed, R.; Jaikumar, P.

2014-08-01

366

Fo(u)r Women.  

PubMed

Abstract This piece is about Fo(u)r Women, a collaborative poly-vocal performance piece featuring music, poetry, prose and movement. It traces the journey from feeling through idea to actualization of a collaborative creative project: how to make a piece of Live Art from the experience of listening to a Nina Simone song and three lives. Dream, breath, hope, wish, act a prayer to you to reach out to touch Four women made flesh in a place of revelation.· In the essay, I explore aspects of process, collaboration, critical context and issues informing the art. Issues of race, gender, sexual identities, relationships, love and place. Dear reader, for those of you at home, it's like you were there, all the time it was being made. But to feel the show, you really have to see it. PMID:24785522

Agbebiyi, A

1998-01-01

367

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

368

Experimental and Computational Tests Involving R-11, R-19 and R-30 Fiberglass Insulations  

Microsoft Academic Search

The attic regions of residential dwellings are important areas with respect to energy conservation. The primary objective of this study is to determine the effective changes in total heat transfer due both to varying the attic insulation thickness from R-11 to R-19 to R-30, and to adding horizontally installed radiant barriers (for R-30). Experimental data (including winter and summer) were

K. T. Harris; T. A. McCarty; J. A. Roux

1994-01-01

369

CONTINUOUS AND DISCONTINUOUS PHASE TRANSITIONS IN HYPERGRAPH PROCESSES  

E-print Network

CONTINUOUS AND DISCONTINUOUS PHASE TRANSITIONS IN HYPERGRAPH PROCESSES R.W.R. DARLING, DAVID A;2 R.W.R. DARLING, D.A. LEVIN, AND J.R. NORRIS 1. Introduction The k-core of a graph is the largest is a special case of another, run on hypergraphs, called hypergraph collapse and first studied in Darling

Levin, David Asher

370

Strong Energy Condition in $R + R^2$ Gravity  

E-print Network

In this paper, we study Raychaudhuri's equation in the background of $R + \\beta R^2$ gravity with a phenomenological matter ($\\rho \\propto a(t)^{-n}$). We conclude that even though the Strong Energy Condition (S.E.C.) for Einstein's gravity, which guarantees singularity, is $n\\geq 2$ for $\\rho \\propto a(t)^{-n}$, a perturbative analysis of Raychaudhuri's equation in the background of $R + \\beta R^2$ gravity reveals that the big bang singularity may not be guaranteed for $n > 4$. We derive the following Strong Energy Conditions for $R + \\beta R^2$ ($\\beta \

J. H. Kung

1995-10-04

371

MiR-223 deficiency increases eosinophil progenitor proliferation  

PubMed Central

Recently, microRNAs (miRNAs) have been shown to be involved in hematopoietic cell development but their role in eosinophilopoeisis has not yet been described. Here we show that miR-223 is up-regulated 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 up-regulation of a miR-223 target gene – IGF1R in the eosinophil progenitor cultures derived from miR-223-/- mice compared to miR-223+/+ littermate controls. The increased proliferation of miR-223-/- eosinophil progenitors was reversed by treatment with the 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 miRNAs 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.

2012-01-01

372

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

373

Comparing specialist medical care with specialist medical care plus the Lightning Process(R) for chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME): study protocol for a randomised controlled trial (SMILE Trial)  

PubMed Central

Background Chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME) is a relatively common and potentially serious condition with a limited evidence base for treatment. Specialist treatment for paediatric CFS/ME uses interventions recommended by National Institute for Health and Clinical Excellence (NICE) including cognitive behavioural therapy, graded exercise therapy and activity management. The Lightning Process® (LP) is a trademarked intervention derived from osteopathy, life-coaching and neuro-linguistic programming, delivered over three consecutive days as group sessions. Although over 250 children with CFS/ME attend LP courses each year, there are no reported studies on the effectiveness or cost-effectiveness. Methods This pragmatic randomised controlled trial is set within a specialist paediatric CFS/ME service in the south west of England. Children and young people with CFS/ME (n?=?80 to 112), aged 12 to 18 years old will be randomised to specialist medical care (SMC) or SMC plus the LP. The primary outcome will be physical function (SF-36 physical function short form) and fatigue (Chalder Fatigue Scale). Discussion This study will tell us whether adding the LP to SMC is effective and cost-effective compared to SMC alone. This study will also provide detailed information on the implementation of the LP and SMC. Trial registration Current Controlled Trials ISRCTN81456207 (31 July 2012). PMID:24370208

2013-01-01

374

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

2012-10-01

375

Phillip R. Owens, p. 1 Phillip R. Owens  

E-print Network

Phillip R. Owens, p. 1 Phillip R. Owens Department of Agronomy Purdue University 915 W. State St Assistant Professor Agronomy Department, Purdue University, West Lafayette, IN 1/05 ­ present 60% Research

Owens, Phillip R.

376

Using R via PHP for Teaching Purposes: R-php  

Microsoft Academic Search

This paper deals with the R-php statistical software, that is an environment for statistical analysis, freely accessible and attainable through the World Wide Web, based on R. Indeed, this software uses, as \\

Angelo M. Mineo; Alfredo Pontillo

2006-01-01

377

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

378

R u t c o r R e p o r t  

E-print Network

1 Introduction One major concern of molecular biology is the sequencing of the human genome and the genomes of other organisms. Unfortunately, sequencing is a slow and error­prone process, and, in the case be determined through the mapping process, allowing sequencers to more easily select a subset which covers

379

Integrative knowledge management to enhance pharmaceutical R&D.  

PubMed

Information technologies already have a key role in pharmaceutical research and development (R&D), but achieving substantial advances in their use and effectiveness will depend on overcoming current challenges in sharing, integrating and jointly analysing the range of data generated at different stages of the R&D process. PMID:24687050

Marti-Solano, Maria; Birney, Ewan; Bril, Antoine; Della Pasqua, Oscar; Kitano, Hiroaki; Mons, Barend; Xenarios, Ioannis; Sanz, Ferran

2014-04-01

380

Non-Double-Couple Earthquake Mechanisms Bruce R. Julian1  

E-print Network

mechanisms near Long Valley caldera, California, Nature, 303, 323-325. Julian, B. R., A. D. Miller, and G. R. Hill, A. M. Pitt, P. Malin, and E. Shalev (2004), Non-double-couple microearthquakes at Long Valley of observations of non-DC earthquakes and analyzes many possible physical non-DC processes. Contrary to long

Foulger, G. R.

381

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

382

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

ERIC Educational Resources Information Center

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

Dondero, Marian; McCoy, Elizabeth

1996-01-01

383

A consistent Markov partition process generated from the paintbox process  

E-print Network

We study a family of Markov processes on $\\mathcal{P}^{(k)}$, the space of partitions of the natural numbers with at most $k$ blocks. The process can be constructed from a Poisson point process on $\\mathbb{R}^+\\times\\prod_{i=1}^k\\mathcal{P}^{(k)}$ with intensity $dt\\otimes\\varrho_{\

Crane, Harry

2011-01-01

384

Genome Biology 2009, 10:R23 Open Access2009Korbelet al.Volume 10, Issue 2, Article R23Software  

E-print Network

Genome Biology 2009, 10:R23 Open Access2009Korbelet al.Volume 10, Issue 2, Article R23Software at considerably enhanced sensitivity, specificity and res-olution over previous approaches. Abstract Personal ends of massively sequenced genome fragments. To process these we developed Paired-End Mapper (PEMer

Gerstein, Mark

385

$R$-Parity Breaking Phenomenology  

E-print Network

We review various features of the $R$-parity breaking phenomenology, with particular attention to the low energy observables, and to the patterns of the $R$-parity breaking interactions that arise in Grand Unified models.

Francesco Vissani

1996-02-26

386

TRD -Your Partner for Technical R&D Pharmaceutical Preformulation  

E-print Network

TRD - Your Partner for Technical R&D Pharmaceutical Preformulation Wei-Qin (Tony) Tong, Ph.D. Novartis Pharmaceuticals Corporation Integrated Drug Product Development Process (3 day-course), University

Tipple, Brett

387

GENERAL PROCESSES IN ASSOCIATIVE LEARNING  

E-print Network

processes #12;Learning Phenomena Nonassociative Associative/Cognitive ·Classical conditioning ·Instrumental closer view at omission training SR SD R Master "SR" "SD" "R" Yoked time #12;Omission training in sexualCopulation 5 TPS ITI mean: 10 min CS dur: 30 s US dur: 30-240 s LAppNothing LnoAppCopul LAppas Master Lno

Cooper, Brenton G.

388

Comparing selfinteracting scalar fields and R + R^3 cosmological models  

E-print Network

We generalize the well-known analogies between m^2 \\phi^2 and R + R^2 theories to include the selfinteraction \\lambda \\phi^4-term for the scalar field. It turns out to be the R + R^3 Lagrangian which gives an appropriate model for it. Considering a spatially flat Friedman cosmological model, common and different properties of these models are discussed, e.g., by linearizing around a ground state the masses of the resp. spin 0-parts coincide. Finally, we prove a general conformal equivalence theorem between a Lagrangian L = L(R), L'L" \

H. -J. Schmidt

2001-06-11

389

INTELLIGENCE 23, 175-190 (1996) The Relationship Between WAIS-R  

E-print Network

INTELLIGENCE 23, 175-190 (1996) The Relationship Between WAIS-R Abilities and Speed of Processing status) 123 participants were tested on the Wechsler Adult Intelligence Scale-Revised (WAIS-R) and a test

Crawford, John R.

390

R-UNSAT  

EPA Science Inventory

Natural attenuation, a remediation strategy that relies on intrinsic physical, chemical, and biological processes to decrease contaminant concentrations, is gaining widespread acceptance in aquifer restoration efforts. The potential for successful remediation by natural attenuati...

391

Becoming A/r/tography  

ERIC Educational Resources Information Center

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

Irwin, Rita L.

2013-01-01

392

Comparative Performance of Heat Pumps and R&D Requirements  

E-print Network

COMPARATIVE PERFORMANCE OF HEAT PUMPS AND R&D REQUIREMENTS M. R. ALLY Research Staff Member Energy Divisi.on Oak Ridge National Laboratory Oak Ridge, Tennessee INTRODUCTION One of the major programs conducted by the U.S. Department... in a role of both increasing the process effi ciencies and recovering and reusing waste energy emitted in industrial manufacturing processes. The lead laboratories doing research in heat pumps in the U.S. are the Oak Ridge National Laboratory (ORNL...

Ally, M. R.

393

Evolution of the miR-290-295/miR-371-373 Cluster Family Seed Repertoire  

PubMed Central

Expression of the mouse miR-290–295 cluster and its miR-371–373 homolog in human is restricted to early embryos, primordial germ cells, the germ line stem cell compartment of the adult testis and to stem cell lines derived from the early embryonic lineages. Sequencing data suggest considerable seed diversification between the seven homologous pre-miRNAs of miR-290–295 but it is not clear if all of the implied miR-290–295 seeds are also conserved in the human miR-371–373 cluster, which consists of only three homologous pre-miRNAs. By employing miRNA target reporters we show that most, if not all, seeds in miR-290–295 are represented in miR-371–373. In the mouse, pre-miR-290, pre-miR-292 and pre-miR-293 express subsets of the miRNA isoforms processed from the single human pre-miR-371. Comparison of the possible miR-290–295/miR-371–373 seed repertoires in placental mammals suggests a model for the evolution of this miRNA cluster family, which would be otherwise difficult to deduce based solely on pre-miRNA sequence comparisons. The conservation of co-expressed seeds that is characteristic of miR-290–295/miR-371–373 should be taken into account in models of the corresponding miRNA-target interaction networks. PMID:25268927

Wu, Shuang; Aksoy, Munevver; Shi, Jianting; Houbaviy, Hristo Botev

2014-01-01

394

75 FR 14069 - Amendment of Using Agency for Restricted Areas R-3005A, R-3305B, R-3005C, R-3005D and R-3005E...  

Federal Register 2010, 2011, 2012, 2013

...R-3005D and R-3005E; Fort Stewart, GA AGENCY: Federal Aviation Administration...R-3005D and R-3005E, Fort Stewart, GA, to ``Commander, U.S. Army Garrison, Fort Stewart, GA.'' There are no changes to the...

2010-03-24

395

Potential role of miR-9 and miR-223 in recurrent ovarian cancer  

PubMed Central

Background MicroRNAs (miRNAs) are small, noncoding RNAs that negatively regulate gene expression by binding to target mRNAs. miRNAs have not been comprehensively studied in recurrent ovarian cancer, yet an incurable disease. Results Using real-time RT-PCR, we obtained distinct miRNA expression profiles between primary and recurrent serous papillary ovarian adenocarcinomas (n = 6) in a subset of samples previously used in a transcriptome approach. Expression levels of top dysregulated miRNA genes, miR-223 and miR-9, were examined using TaqMan PCR in independent cohorts of fresh frozen (n = 18) and FFPE serous ovarian tumours (n = 22). Concordance was observed on TaqMan analysis for miR-223 and miR-9 between the training cohort and the independent test cohorts. Target prediction analysis for the above miRNA "recurrent metastatic signature" identified genes previously validated in our transcriptome study. Common biological pathways well characterised in ovarian cancer were shared by miR-9 and miR-223 lists of predicted target genes. We provide strong evidence that miR-9 acts as a putative tumour suppressor gene in recurrent ovarian cancer. Components of the miRNA processing machinery, such as Dicer and Drosha are not responsible for miRNA deregulation in recurrent ovarian cancer, as deluded by TaqMan and immunohistochemistry. Conclusion We propose a miRNA model for the molecular pathogenesis of recurrent ovarian cancer. Some of the differentially deregulated miRNAs identified correlate with our previous transcriptome findings. Based on integrated transcriptome and miRNA analysis, miR-9 and miR-223 can be of potential importance as biomarkers in recurrent ovarian cancer. PMID:18442408

Laios, Alexandros; O'Toole, Sharon; Flavin, Richard; Martin, Cara; Kelly, Lynn; Ring, Martina; Finn, Stephen P; Barrett, Ciara; Loda, Massimo; Gleeson, Noreen; D'Arcy, Tom; McGuinness, Eamonn; Sheils, Orla; Sheppard, Brian; O' Leary, John

2008-01-01

396

Algebraic treatment of the potential V(r)=-v/r[1-r?(1-1/Z)/(1+r?)  

NASA Astrophysics Data System (ADS)

The discrete energy levels Enl of the Schrödinger Hamiltonian H=-(1/2?+V(r), where V(r)=-(v/r)[1-r?(1-1/Z)/(1+r?)] have been analyzed using the dynamical group formulation of the scaling variational method. A simple analytical formula has been obtained which gives the energy value of different states for various values of Z. We have also found out the exact numerical eigenvalues for the above potential for the 1S, 2S, 2P, 3S, 3P, and 3D cases, and the energy values given by the dynamical group method are in excellent agreement with the exact numerical ones.

Roychoudhury, Rajkumar; Roy, Barnana; Varshni, Y. P.

1988-10-01

397

miR-223: infection, inflammation and cancer.  

PubMed

Expression of the microRNA miR-223 is deregulated during influenza or hepatitis B infection and in inflammatory bowel disease, type 2 diabetes, leukaemia and lymphoma. Although this may also be the result of the disease per se, increasing evidence suggests a role for miR-223 in limiting inflammation to prevent collateral damage during infection and in preventing oncogenic myeloid transformation. Validated targets for miR-223 that have effects on inflammation and infection include granzyme B, IKK?, Roquin and STAT3. With regard to cancer, validated targets include C/EBP?, E2F1, FOXO1 and NFI-A. The effect of miR-223 on these targets has been documented individually; however, it is more likely that miR-223 affects multiple targets simultaneously for key processes where the microRNA is important. Such processes include haematopoietic cell differentiation, particularly towards the granulocyte lineage (where miR-223 is abundant) and as cells progress down the myeloid lineage (where miR-223 expression decreases). NF-?B and the NLRP3 inflammasome are important inflammatory mechanisms that are dampened by miR-223 in these cell types. The miRNA can also directly target viruses such as HIV, leading to synergistic effects during infection. Here we review the recent studies of miR-223 function to show how it modulates inflammation, infection and cancer development. PMID:23772809

Haneklaus, M; Gerlic, M; O'Neill, L A J; Masters, S L

2013-09-01

398

RCircos: an R package for Circos 2D track plots  

PubMed Central

Background Circos is a Perl language based software package for visualizing similarities and differences of genome structure and positional relationships between genomic intervals. Running Circos requires extra data processing procedures to prepare plot data files and configure files from datasets, which limits its capability of integrating directly with other software tools such as R. Recently published R Bioconductor package ggbio provides a function to display genomic data in circular layout based on multiple other packages, which increases its complexity of usage and decreased the flexibility in integrating with other R pipelines. Results We implemented an R package, RCircos, using only R packages that come with R base installation. The package supports Circos 2D data track plots such as scatter, line, histogram, heatmap, tile, connectors, links, and text labels. Each plot is implemented with a specific function and input data for all functions are data frames which can be objects read from text files or generated with other R pipelines. Conclusion RCircos package provides a simple and flexible way to make Circos 2D track plots with R and could be easily integrated into other R data processing and graphic manipulation pipelines for presenting large-scale multi-sample genomic research data. It can also serve as a base tool to generate complex Circos images. PMID:23937229

2013-01-01

399

Nucleate boiling performance of R-22, R-123, R-134a, R-410A, and R-407C on smooth and enhanced tubes  

SciTech Connect

Investigation of the nucleate boiling heat transfer on several commercially available enhanced tubes and smooth tubes was carried out in this study. The working refrigerants included R-22, R-123, R-134a, R-410A, and R-407C. Experiments were conducted at saturation temperatures of 0 C and 20 C. For the W-TX tube at a given saturation temperature, the heat transfer coefficients for R-410A are the largest and for R-123 are the lowest. For the highly structured surface, W-B tube, the heat transfer coefficients for R-22 and R-410A are comparable, while the heat transfer coefficients for R-407C are the lowest.

Wang, C.C.; Chang, Y.J. [Industrial Technology Research Inst., Hsinchu (Taiwan, Province of China). Energy and Research Labs.; Shieh, W.Y.; Yang, C.Y. [National Central Univ., Chung Li (Taiwan, Province of China). Dept. of Mechanical Engineering

1998-10-01

400

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

401

DrillfieldDr. P E R R Y S T R E E T  

E-print Network

Burruss Hall Admissions Academic Buildings Burruss Hall Student Center Derring Hall New Virginia TechAlumniMall DrillfieldDr. P E R R Y S T R E E T DerringHall Pamplin Hall Norris HallHoldenHall Hancock Hall WhittemoreHall Bishop- Favrao Hall BurrussHall Randolph Hall Cowgill Hall Chemistry Physics

Buehrer, R. Michael

402

R-trees Have Grown Everywhere  

Microsoft Academic Search

bulk-loading. It seems that due to the modern demanding applications and after the academia has paved the way, recently the industry recognized the use and necessity of R-trees. The simplicity of the structure and its resemblance to the B-tree, allowed developers to easily incorporate the structure into existing database management systems in order to support spatial query processing. In this

YANNIS MANOLOPOULOS; ALEXANDROS NANOPOULOS; APOSTOLOS N. PAPADOPOULOS

403

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

404

r-Java 2.0: the nuclear physics  

E-print Network

[Aims:] We present r-Java 2.0, a nucleosynthesis code for open use that performs r-process calculations as well as a suite of other analysis tools. [Methods:] Equipped with a straightforward graphical user interface, r-Java 2.0 is capable of; simulating nuclear statistical equilibrium (NSE), calculating r-process abundances for a wide range of input parameters and astrophysical environments, computing the mass fragmentation from neutron-induced fission as well as the study of individual nucleosynthesis processes. [Results:] In this paper we discuss enhancements made to this version of r-Java, paramount of which is the ability to solve the full reaction network. The sophisticated fission methodology incorporated into r-Java 2.0 which includes three fission channels (beta-delayed, neutron-induced and spontaneous fission) as well as computation of the mass fragmentation is compared to the upper limit on mass fission approximation. The effects of including beta-delayed neutron emission on r-process yield is studi...

Kostka, M; Shand, Z; Ouyed, R; Jaikumar, P

2014-01-01

405

R-Local Delaunay Inhibition Model  

NASA Astrophysics Data System (ADS)

Unlike in the classical framework of Gibbs point processes (usually acting on the complete graph), in the context of nearest-neighbour Gibbs point processes the nonnegativeness of the interaction functions do not ensure the local stability property. This paper introduces domain-wise (but not pointwise) inhibition stationary Gibbs models based on some tailor-made Delaunay subgraphs. All of them are subgraphs of the R-local Delaunay graph, defined as the Delaunay subgraph specifically not containing the edges of Delaunay triangles with circumscribed circles of radii greater than some large positive real value R. The usual relative compactness criterion for point processes needed for the existence result is directly derived from the Ruelle-bound of the correlation functions. Furthermore, assuming only the nonnegativeness of the energy function, we have managed to prove the existence of the existence of R-local Delaunay stationary Gibbs states based on nonnegative interaction functions thanks to the use of the compactness of sublevel sets of the relative entropy.

Bertin, Etienne; Billiot, Jean-Michel; Drouilhet, Rémy

2008-08-01

406

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...

407

Project Report EE 371R Digital Image Processing  

E-print Network

by imperceptibly embedding it into the digital media. The purpose of embedding such information depends on the application and the needs of the owner/user of the digital media. Current main applications of watermarking/owner of the digital media in order to prevent other parties from claiming the ownership of the media. 2

Mutlu, Onur

408

ION TRANSPORT PROCESSES OF INVERTEBRATE GASTROINTESTINAL DIVERTICULA. (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...

409

R&D for graft adsorbents by radiation processing  

NASA Astrophysics Data System (ADS)

Fibrous adsorbent for removal and recovery of metal ions have been synthesized by graft polymerization. In the grafting, the functional groups which have high selectivity against for target metal ions such as Fe, Sc, As, and U are introduced onto nonwoven fabric. When the monomer has a chelate group which makes selective coordination bond to specific these ions, it was directly grafted on the trunk polymer. In the case of precursor monomer having functional groups such as epoxy ring, the grafted trunk fabric is chemically modified. The resultant fibrous adsorbent leads the swift adsorption of metal ions. This property by using fibrous material can reduce the column size of adsorbent in the purification of waste water. The size of purification equipment becomes quite compact and that implies total volume of equipment can reduce. Instead of organic solvent, emulsion system which disperses monomer micelles in water with assistance of surfactant was found to accelerate the graft polymerization. This means the air pollution from organic solvent can be avoided by water system grafting. Furthermore, since the emulsion grafting was highly efficient, the required irradiation dose was considerably lower compared to general organic solvent system. As a result, the emulsion grafting has enormous potential for natural polymer to use as a trunk material for grafting. If a natural polymer such as cellulose can be used, the dependence on petroleum resources, the amount of industrial waste and the generation of carbon dioxide will be reduced to some extent.

Seko, Noriaki; Tamada, Masao

410

R u t c o r R e p o r t  

E-print Network

­445­5472 Email: rrr@rutcor.rutgers.edu http://rutcor.rutgers.edu/ rrr Solution of a Product Substitution Problem accounting for the uncertainty primarily in the yield and secondly in the demand. The model is solved process. They may break, though. The fibers obtained are the primary products. After some cutting has been

411

Readings in R. Ramamurthi  

E-print Network

givenwhichstronglysuggestthe presenceof a complex,intelligentbehaviour. INTRODUCTION Do animals behave intelligently? Do in the cause of the study of animal intelligence and thought processes [1-3]. His books provide a fascinating commentary of the complex and intelligent things that a wide variety of animals are capable of doing

Gadagkar, Raghavendra

412

The Failure of R0  

PubMed Central

The basic reproductive ratio, R0, is one of the fundamental concepts in mathematical biology. It is a threshold parameter, intended to quantify the spread of disease by estimating the average number of secondary infections in a wholly susceptible population, giving an indication of the invasion strength of an epidemic: if R0 < 1, the disease dies out, whereas if R0 > 1, the disease persists. R0 has been widely used as a measure of disease strength to estimate the effectiveness of control measures and to form the backbone of disease-management policy. However, in almost every aspect that matters, R0 is flawed. Diseases can persist with R0 < 1, while diseases with R0 > 1 can die out. We show that the same model of malaria gives many different values of R0, depending on the method used, with the sole common property that they have a threshold at 1. We also survey estimated values of R0 for a variety of diseases, and examine some of the alternatives that have been proposed. If R0 is to be used, it must be accompanied by caveats about the method of calculation, underlying model assumptions and evidence that it is actually a threshold. Otherwise, the concept is meaningless. PMID:21860658

Li, Jing; Blakeley, Daniel; Smith?, Robert J.

2011-01-01

413

Stability of r-minimal cones in R  

NASA Astrophysics Data System (ADS)

The study of minimal cones C(M) in R construed over compact minimal hypersurface M of a unit Euclidean sphere Sn has an important link with the Bernstein problem, see e.g. Bombieri et al. [E. Bombieri, E. de Giorgi, E. Giusti, Minimal cones and Bernstein problem, Invent. Math. 7 (1969) 243-268]. It was studied by many authors with a remarkable paper due to Simmons [J. Simmons, Minimal varieties in Riemannian manifolds, Ann. of Math. 88 (1968) 62-105]. In a recent work Barbosa and Do Carmo [J.L.M. Barbosa, M.P. Do Carmo, On the stability of cones in R with zero scalar curvature, Ann. Global Anal. Geom. 28 (2005) 107-122] treated cones in R with the second function of curvature S2=0 and S3?=0. In these papers the authors showed the existence of a truncated cone which is unstable as well as truncated cones over Clifford tori that are stable. Here we partially extend such results for cones construed over compact hypersurfaces M of the unit sphere Sn with Sr=0 and S?=0 by showing that there exists ?>0 for which the truncated cone C( is (r-1)-unstable provided n?r+5. Moreover, we also show that for n?r+6 there exists a Clifford torus Sp(r1)×Sq(r2)?Sn with Sr=0 and S?=0, for which all truncated cones based on such a torus are (r-1)-stable.

Barros, A.; Sousa, P.

2008-10-01

414

Static Spherically Symmetric Solution of (R +- ?^4/R) Gravity  

E-print Network

The static spherically symmetric solution for (R +- {\\mu}^4/R) model of f(R)gravity is investigated. We obtain the metric for space-time in the solar system that reduces to the Schwarzschild metric, when {\\mu} tends to zero. For the obtained metric, the deviation from Einstein gravity is very small. This result is different from the other results have been obtained by equivalence between f(R) gravity and scalar tensor theory. Also it is shown that the vacuum solution in the solar system depends on the shape of matter distribution which differ from the Einstein's gravity.

Kh. Saaidi; A. Vaji; A. Aghamomammadi

2010-01-23

415

Process for functionalizing alkanes  

DOEpatents

Process for functionalizing saturated hydrocarbons comprising: (a) reacting said saturated hydrocarbons of the formula: R.sub.1 H wherein H represents a hydrogen atom; and R.sub.1 represents a saturated hydrocarbon radical, with a metal complex of the formula: CpRh[P(R.sub.2).sub.3 ]H.sub.2 wherein Cp represents a cyclopentadienyl or alkylcyclopentadienyl radical; Rh represents a rhodium atom; P represents a phosphorus atom; R.sub.2 represents a hydrocarbon radical; H represents a hydrogen atom, in the presence of ultraviolet radiation to form a hydridoalkyl complex of the formula: CpRh[P(R.sub.2).sub.3 ](R.sub.1)H (b) reacting said hydridoalkyl complex with an organic halogenating agent such as a tetrahalomethane or a haloform of the formulas: CX'X''X'''X'''' or CHX'X''X''' wherein X', X'', X'", X"" represent halogens selected from bromine, iodine or chlorine atom, at a temperature in the range of about -60.degree. to -17.degree. C. to form the corresponding haloalkyl complex of step (a) having the formula: CpRhPMe.sub.3 RX; and, (c) reacting said haloalkyl complex formed in (b) with halogen (X.sub.2) at a temperature in the range of about -60.degree. to 25.degree. C. (i.e., ambient) to form a functional haloalkyl compound.

Bergman, Robert G. (Kensington, CA); Janowicz, Andrew H. (Wilmington, DE); Periana, Roy A. (Berkeley, CA)

1988-01-01

416

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 !

BEGIN:VCARD VERSION:2.1 FN:Richard Benz N:Benz;Richard ORG:Wickliffe High School REV:2005-04-12 END:VCARD

1994-07-30

417

Lauren R. Donaldson Collection  

NSDL National Science Digital Library

In 1946, Lauren R. Donaldson and several of his scientific colleagues were selected as radiation monitors for Operation Crossroads, which was the codename for the first atomic bomb tests at Bikini Atoll. During this operation, two nuclear bombs were detonated above and below the ocean surface, contaminating the organs and tissues of living creatures and plants with large doses of radioactivity. Over the next twelve years, Dr. Donaldson and his colleagues would return a number of times to perform research related to these activities. Recently, the University of Washington Libraries Digital Collections team digitized selected personal logs, photo albums, papers, and ephemera from the surveys undertaken by this team of researchers. Visitors can browse the collection, or they may wish to get started by looking over the sample searches which include "1946 Operation Crossroads" and "1947 Bikini Atoll Radiological Survey". Also, visitors can learn more about Dr. Donaldson and peruse a finding aid for his own personal and academic papers which are also held by the University of Washington.

418

Optimal stopping of Hunt and Lvy processes  

E-print Network

Optimal stopping of Hunt and Lévy processes Ernesto Mordecki Universidad de la República, Cento de The optimal stopping problem for a Hunt processes on R is consid- ered via the representation theory processes, Hunt processes, Lévy processes, Green kernel, diusions with jumps, Riesz decomposition. AMS

Mordecki, Ernesto

419

Regulation of the Response Regulator Gene degU through the Binding of SinR/SlrR and Exclusion of SinR/SlrR by DegU in Bacillus subtilis  

PubMed Central

Bacillus subtilis DegU is a response regulator of the DegS-DegU two-component regulatory system. Phosphorylated DegU (DegU-P) controls many genes and biological processes, such as exoprotease and ?-polyglutamic acid production, in addition to the degU gene, by binding to target gene promoters. Nonphosphorylated DegU and low levels of DegU-P are required for swarming motility and genetic competence. The DNA-binding repressors SinR and SlrR are part of a double-negative feedback loop and comprise the epigenetic switch governing biofilm formation. In this study, we found that SinR repressed degU. Furthermore, SlrR, which interacts with SinR through protein-protein interaction, seems to have an active role in degU expression in in vivo lacZ analysis. An in vitro transcription assay supported this observation. An electrophoretic mobility shift assay (EMSA) showed that SinR bound to the degU promoter and that SlrR formed a complex with SinR on the degU promoter. In EMSA, DegU-P excluded the SinR/SlrR complex but not SinR from the degU promoter in the presence of RNA polymerase. These findings suggest that DegU-P interacts with SlrR. In support of this hypothesis, disruption of the slrR gene resulted in decreased degU expression. This newly identified regulatory mechanism for degU is considered to be sequential transcription factor replacement. PMID:24317403

Yoshikawa, Hirofumi; Chibazakura, Taku

2014-01-01

420

Retrotransposable elements R1 and R2 interrupt the rRNA genes of most insects.  

PubMed Central

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 greater than 50% of the 28S genes. Sequence analysis of these insertions from 8 species revealed 22 elements, 21 of which corresponded to R1 or R2 elements. Surprisingly, many species appeared to contain highly divergent copies of R1 and R2 elements. For example, a parasitic wasp contained at least four families of R1 elements; the Japanese beetle contained at least five families of R2 elements. The presence of these retrotransposable elements throughout Insecta and the observation that single species can harbor divergent families within its rRNA-encoding DNA loci present interesting questions concerning the age of these elements and the possibility of cross-species transfer. Images PMID:1849649

Jakubczak, J L; Burke, W D; Eickbush, T H

1991-01-01

421

R E P O R T A showcase of the  

E-print Network

college UCLA R E P O R T A showcase of the people and progress from the liberal arts and sciences and the State Legislature will provide the support needed to maintain the superb level of higher education funding, two issues are clear. First, the problems with the state budget magnify the importance

Grether, Gregory

422

R e p o r t s Autumn 2003  

E-print Network

the cicadas, leaf- hopper females use their swordlike ovi- positors to cut the plant skin and inject the eggs1 ILLINOIS NATURAL HISTORY S U RVE Y R e p o r t s Autumn 2003 No. 377 I N S I D E Egg:" Soybean Herbivory Influences Western Corn Rootworm Behavior and Egg- laying 4 Understanding the Public

Taylor, Steven J.

423

Summer 2007 Volume Eight R E P O R T  

E-print Network

on the complex issues that involve global climate change and its effect on regions and environments. 10 A Unique for faculty and students from three departments in the College, the 176,000-square- foot facilitySummer 2007 Volume Eight R E P O R T COLLEGE OF LETTERS AND SCIENCE #12;A showcase of the people

Grether, Gregory

424

"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

425

Clementine Sensor Processing System  

NASA Technical Reports Server (NTRS)

The design of the DSPSE Satellite Controller (DSC) is baselined as a single-string satellite controller. The DSC performs two main functions: health and maintenance of the spacecraft; and image capture, storage, and playback. The DSC contains two processors: a radiation-hardened Mil-Std-1750, and a commercial R3000. The Mil-Std-1750 processor performs all housekeeping operations, while the R3000 is mainly used to perform the image processing functions associated with the navigation functions, as well as performing various experiments. The DSC also contains a data handling unit (DHU) used to interface to various spacecraft imaging sensors and to capture, compress, and store selected images onto the solid-state data recorder. The development of the DSC evolved from several key requirements; the DSPSE satellite was to do the following: (1) have a radiation-hardened spacecraft control system and be immune to single-event upsets (SEU's); (2) use an R3000-based processor to run the star tracker software that was developed by SDIO (due to schedule and cost constraints, there was no time to port the software to a radiation-hardened processor); and (3) fly a commercial processor to verify its suitability for use in a space environment. In order to enhance the DSC reliability, the system was designed with multiple processing paths. These multiple processing paths provide for greater tolerance to various component failures. The DSC was designed so that all housekeeping processing functions are performed by either the Mil-Std-1750 processor or the R3000 processor. The image capture and storage is performed either by the DHU or the R3000 processor.

Feldstein, A. A.

1993-01-01

426

Clementine sensor processing system  

NASA Astrophysics Data System (ADS)

The design of the DSPSE Satellite Controller (DSC) is baselined as a single-string satellite controller. The DSC performs two main functions: health and maintenance of the spacecraft; and image capture, storage, and playback. The DSC contains two processors: a radiation-hardened Mil-Std-1750, and a commercial R3000. The Mil-Std-1750 processor performs all housekeeping operations, while the R3000 is mainly used to perform the image processing functions associated with the navigation functions, as well as performing various experiments. The DSC also contains a data handling unit (DHU) used to interface to various spacecraft imaging sensors and to capture, compress, and store selected images onto the solid-state data recorder. The development of the DSC evolved from several key requirements; the DSPSE satellite was to do the following: (1) have a radiation-hardened spacecraft control system and be immune to single-event upsets (SEU's); (2) use an R3000-based processor to run the star tracker software that was developed by SDIO (due to schedule and cost constraints, there was no time to port the software to a radiation-hardened processor); and (3) fly a commercial processor to verify its suitability for use in a space environment. In order to enhance the DSC reliability, the system was designed with multiple processing paths. These multiple processing paths provide for greater tolerance to various component failures. The DSC was designed so that all housekeeping processing functions are performed by either the Mil-Std-1750 processor or the R3000 processor. The image capture and storage is performed either by the DHU or the R3000 processor.

Feldstein, A. A.

427

Small deviations for the Poisson process  

Microsoft Academic Search

Let Nt be a Poisson process, we study the asymptotic estimates for probabilities of the form P(?Nt ? atƒ? ? ? at1r), where r > 0, ƒ ? K where K is the Strassen's set and at is a real sequence satisfying suitable conditions of growth and regularity. This type of result for Poisson process seems new. Finally, we establish

Sergio Alvarez-Andrade

1998-01-01

428

Implementing Spatial Segregation Measures in R  

PubMed Central

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

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

2014-01-01

429

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

430

Compound R2 R3 R6 ( mol/min/mg)  

E-print Network

Compound R2 R3 R6 Metabolism ( mol/min/mg) NADH oxidation (by HPLC) Metabolism by NQO1 ( mol/min/mg) (cytochrome c reduction) 1 HP460 Me H OMe 20.7 ± 3.7 342 ± 22.9 2 TF03 Cl H OMe 100 ± 32.0 420 ± 40.1 3 TF02 cytochrome c as the terminal electron acceptor. Toxicity was determined by the MTT colorimetric assay

Vonessen, Nikolaus

431

Nonlinear Processes in Geophysics (2001) 8: 439448 Nonlinear Processes  

E-print Network

Nonlinear Processes in Geophysics (2001) 8: 439­448 Nonlinear Processes in Geophysics c European Geophysical Society 2001 Lyapunov, Floquet, and singular vectors for baroclinic waves R. M. Samelson College of geophysical fluid flows is an impor- tant and interesting scientific issue, which combines prac- tical

Boyer, Edmond