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1

r-Process Abundance Signatures  

E-print Network

Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. These observations demonstrate that the earliest generations of stars in the Galaxy, responsible for neutron-capture synthesis and the progenitors of the halo stars, were rapidly evolving. Abundance comparisons among large numbers of stars provide clues about the nature of neutron-capture element synthesis both during the earliest times and throughout the history of the Galaxy. In particular, these comparisons suggest differences in the way the heavier (including Ba and above) and lighter neutron capture elements are synthesized in nature. Understanding these differences will help to identify the astrophysical site (or sites) of and conditions in the r-process. The abundance comparisons also demonstrate a large star-to-star scatter in the neutron-capture/iron ratios at low metallicities- which disappears with increasing [Fe/H]- and suggests an early, chemically unmixed and inhomogeneous Galaxy. The very recent neutron-capture element observations indicate that the early phases of Galactic nucleosynthesis, and the associated chemical evolution, are quite complex, with the yields from different (progenitor) mass-range stars contributing to different chemical mixes. Stellar abundance comparisons suggest a change from the r-process to the slow neutron capture (i.e., s-) process at higher metallicities (and later times) in the Galaxy. Finally, the detection of thorium and uranium in halo and globular cluster stars offers a promising, independent age-dating technique that can put lower limits on the age of the Galaxy and thus the Universe.

J. J. Cowan; C. Sneden

2002-12-05

2

Physical conditions for the r-process  

SciTech Connect

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

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

2012-11-12

3

Advances in r-Process Nucleosynthesis  

E-print Network

During the last several decades, there have been a number of advances in understanding the rapid neutron-capture process (i.e., the r-process). These advances include large quantities of high-resolution spectroscopic abundance data of neutron-capture elements, improved astrophysical models, and increasingly more precise nuclear and atomic physics data. The elemental abundances of the heavy neutron-capture elements, from Ba through the third r-process peak, in low-metallicity ([Fe/H] = 56 the r-process is robust--appearing to operate in a relatively consistent manner over the history of the Galaxy--and place stringent constraints on r-process models. While not yet identified, neutron-rich ejecta outside of the core in a collapsing (Type II, Ib) supernova continues to be a promising site for the r-process. Neutron star binary mergers might also be a possible alternative site. Abundance comparisons of lighter n-capture elements in halo stars show variations with the scaled solar r-process curve and might suggest either multiple r-process sites, or, at least, different synthesis conditions in the same astrophysical site. Constraints on r-process models and clues to the progenitors of the halo stars--the earliest generations of Galactic stars--are also provided by the star-to-star abundance scatter of [Eu/Fe] at low metallicities in the early Galaxy. Finally, abundance observations of long-lived radioactive elements (such as Th and U) produced in the r-process can be used to determine the chronometric ages of the oldest stars, placing constraints on the lower limit age estimates of the Galaxy and the Universe.

John J. Cowan; Christopher Sneden

2003-09-29

4

Neutrino Capture and r-Process Nucleosynthesis  

E-print Network

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

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

1998-09-18

5

Ris-R-1582(EN) Innovation Process  

E-print Network

Risø-R-1582(EN) Innovation Process By Andrei Kolodovski for Risø Risø National Laboratory Roskilde Denmark December 2006 #12;Author: Andrei Kolodovski for Risø Title: Innovation Process Department: Risø system - Report provides innovation methodology to establish common understanding of the process concepts

6

R-process Nucleosynthesis in Supernova Explosion  

SciTech Connect

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

Saruwatari, M.; Hashimoto, M. [Department of Physics, School of Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Kotake, K. [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Yamada, S. [Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjyuku, Tokyo, 169-8555 (Japan)

2011-10-28

7

r-Process Enhanced Halo Stars  

E-print Network

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

J. J. Cowan; C. Sneden; J. E. Lawler; E. A. Den Hartog

2006-10-13

8

The r-Process and Chronometers  

E-print Network

We present detailed abundance observations of the metal-poor ([Fe/H] = --2.0) Galactic halo star BD+17 3248. We have detected gold in this star, for the first time in any halo star. We also detected a weak line at 3859.60 A in the spectrum of BD+17 3248 that we tentatively identify with uranium. This would be only the second such detection of this radioactive element in any metal-poor halo stars. Similarly to the case of CS 22892--052, the heavier n-capture elements (Z >= 56) fall on the scaled solar system r-process abundance curve, while the elements with Z = 40--50 in BD+17 3248 fall below that same solar curve. Employing the newly detected Th, U and third r-process peak element (e.g., Pt, Ir) abundances, chronometric age estimates have been made for BD+17 3248. The average value of the various chronometric pairs suggests an age of 13.8 +/- 4 Gyr for this star, consistent, within error limits, with other chronometric age determinations for metal-poor Galactic halo stars.

John J. Cowan; Christopher Sneden; James W. Truran

2002-04-17

9

Astrophysical Models of r-Process Nucleosynthesis: An Update  

E-print Network

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

Yong-Zhong Qian

2012-01-24

10

Astrophysical models of r-process nucleosynthesis: An update  

SciTech Connect

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

Qian Yongzhong [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2012-11-12

11

Sensitivity studies for the weak r process: neutron capture rates  

SciTech Connect

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

Surman, R., E-mail: surmanr@union.edu [Department of Physics and Astronomy, Union College, Schenectady, NY 12308 (United States); Mumpower, M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)] [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Sinclair, R.; Jones, K. L. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States)] [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Hix, W. R. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States) [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); McLaughlin, G. C. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States)] [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States)

2014-04-15

12

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

13

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

14

R-Process in Collapsing O/Ne/Mg Cores  

E-print Network

Several circumstantial arguments point to the formation of the third r-process peak at A about 190, near platinum, in stars of mass of about 8-10 solar masses: 1) The delayed production of europium with respect to iron imposes a time scale that restricts the progenitor stars to less than about 10 solar masses; 2) the r-process demands a dominant robust mechanism at least for barium and above, since the relative abundance pattern of those r-process elements in low-metallicity stars is consistent with the solar pattern; 3) stars of about 8-10 solar masses produce nearly identical degenerate O/Ne/Mg cores that collapse due to electron capture; and 4) the resulting low-mass cores may produce both an r-process in a prompt explosion and a subsequent r-process in a neutrino driven wind. The prompt explosion of an O/Ne/Mg core yields low entropy and low electron fraction, and hence may produce a reasonable r-process peak at A about 190 as well as all of the r-process elements with Z greater than 56. The possible differences in the neutrino-driven wind and associated r-process due to the low-mass neutron stars expected in this mass range are also discussed.

J. Craig Wheeler; John J. Cowan; Wolfgang Hillebrandt

1997-11-22

15

r-Process in Prompt Supernova Explosions Revisited  

E-print Network

We reanalyze $r$-process nucleosynthesis in the neutron-rich ejecta from a prompt supernova explosion of a low-mass (11 M$_\\odot$) progenitor. A pompt explosion is not yet ruled out as a possibility for low-mass supernova progenitors. Moreover, there is mounting evidence that a new $r$-process site may be required. Hence, we assume that a prompt explosion can occur and make a study of r-process nucleosynthesis in the supernova ejecta. To achieve a prompt explosion we have performed a general relativistic hydrodynamic simulation of adiabatic collapse and bounce using a relativistic nuclear-matter equation of state. The electron fraction $Y_e$ during the collapse was fixed at the initial-model value. The size of the inner collapsing core was then large enough to enable a prompt explosion to occur. Adopting the calculated trajectories of promptly ejected material, we explicitly computed the burst of neutronization due to electron captures on free protons in the photodissociated ejecta after the passage of the shock. The thermal and compositional evolution of the resulting neutron-rich ejecta originating from near the surface of proto-neutron star was obtained. These were used in nuclear reaction network calculations to evaluate the products of $r$-process nucleosynthesis. We find that, unlike earlier studies, the amount of $r$-process material ejected per supernova is quite consistent with observed galactic $r$-process abundances. Furthermore, the computed $r$-process abundances are in good agreement with Solar abundances of $r$-process elements for A$> 100$. This suggests that prompt supernovae are still a viable $r$-process site. Such events may be responsible for the abundances of the heaviest $r$-process nuclei.

K. Sumiyoshi; M. Terasawa; G. J. Mathews; T. Kajino; S. Yamada; H. Suzuki

2001-08-13

16

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

SciTech Connect

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.; Aprahamian, A. [Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States)] [Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Surman, R. [Department of Physics and Astronomy, Union College, Schenectady, New York 12308 (United States)] [Department of Physics and Astronomy, Union College, Schenectady, New York 12308 (United States)

2014-04-15

17

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. Martnez-Pinedo; K. -H. Schmidt; W. R. Hix; I. Panov; T. Rauscher; F. -K. Thielemann; N. Zinner

2008-12-04

18

Neutron capture rates and r-process nucleosynthesis  

E-print Network

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

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

2013-08-31

19

Constraints on r-process nucleosynthesis in accretion disks  

NASA Technical Reports Server (NTRS)

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

Jin, Liping

1991-01-01

20

The Heaviest Elements: r-Process Abundances In The Galaxy  

NASA Astrophysics Data System (ADS)

The origin of r-process elements in the Milky Way is poorly understood. We measure the abundance of europium, an r-process element, in Galactic thin disk stars. With nearly one thousand Keck I HIRES spectra for stars that have 0.5 < B-V < 1.5 and -0.5 < [Fe/H] < 0.5, we expect to place strong constraints on the origin of the r-process, both in spatial distribution and through the Galaxy's history. We present here progress to date in an abundance analysis of europium in nearby (d < 100 pc) F, G, and K stars, derived from an LTE spectral synthesis code. As an s-process marker, we also present an analysis of lanthanum abundance in the same stars. We include for comparison our fit to the Eu and La lines in the sun and in eighteen stars previously measured in literature abundance work. Our europium abundances lay the foundation for future investigation of lines from other elements, like the pure r-process element thorium. With these techniques in hand, we hope to establish an r-process abundance pattern derived from hundreds of solar-type stars, and use relative abundances of r-process and s-process elements to gain insight into the history of heavy-element nucleosynthesis in the solar neighborhood. This work is supported by a NASA grant managed by the University of California at Berkeley.

Peek, Kathryn M.; Marcy, G.

2007-05-01

21

Cosmochemistry S-and R-processes in nucleosynthesis  

E-print Network

Cosmochemistry [4] S- and R-processes in nucleosynthesis Condensation sequence in the solar system The first solids SN 1987A September 18, 2014 #12;Heavy element nucleosynthesis Glenn Seaborg (1912-1999) #12;s-process nucleosynthesis S-process is the successive n-capture by seed nuclei (e.g. Ne, Fe

Mojzsis, Stephen J.

22

r-Process Elements in the Milky Way  

NASA Astrophysics Data System (ADS)

The origin and distribution of r-process elements in the Milky Way are poorly understood. To unravel the chemical evolution history of the Galaxy, we are working to measure the abundances of europium and other r-process elements in solar-metallicty Galactic thin disk stars. With nearly one thousand S/N 100 Keck I HIRES spectra of stars with 0.5 < B-V < 1.5 and -0.5 < [Fe/H] < 0.5, we expect to place strong constraints on the origin of the r-process, both in spatial distribution and through the Galaxy's history. We present here progress to date in an ongoing abundance analysis of europium in nearby (d < 100 pc) F, G, and K stars, abundances determined with an LTE spectral synthesis code. We include for comparison our fit to the Eu lines in the sun and in a handful of stars that have been previously measured in literature abundance work. Our europium abundances lay the foundation for future investigation of lines from other elements, like the pure r-process element thorium. With these techniques in hand, we hope to establish an r-process abundance pattern derived from hundreds of solar-type stars, and use relative abundances of r-process and s-process elements to gain insight into the history of heavy-element nucleosynthesis in the solar neighborhood. This work has been supported by a NASA grant managed by the University of California at Berkeley.

Peek, Kathryn M. G.; Marcy, G. W.

2007-12-01

23

Galactic r-process production: The inhomogeneous approach  

E-print Network

The origin of elements made by the rapid neutron-capture process (r-process) is not fully understood. Different sources have been proposed, e.g., core-collapse supernovae and neutron star mergers. Old metal-poor stars carry the signature of the astrophysical r-process source(s). Europium is the most indicative element to trace the r-process production, since it is mostly made by the r-process and it is easy to observe compared to other heavy r-process elements. In this work we simulate the evolution of europium in our Galaxy with the inhomogeneous chemical evolution model ICE, and we compare our results with spectroscopic observations. We test the most important parameters affecting the chemical evolution of the r-process element Eu: (a) for neutron star mergers the coalescence time scale of the merger and the probability to experience a neutron star merger event after two supernova explosions occurred and formed a double neutron star system ) and (b) for the sub-class of magneto-rotationally driven Supernova...

Wehmeyer, B; Thielemann, F -K

2015-01-01

24

r-Process Enhanced Halo Stars  

Microsoft Academic Search

Abundance observations indicate the presence of rapid-neutron capture (i.e.,\\u000ar-process) elements in old Galactic halo and globular cluster stars. These\\u000aobservations provide insight into the nature of the earliest generations of\\u000astars in the Galaxy -- the progenitors of the halo stars -- responsible for\\u000aneutron-capture synthesis of the heavy elements. The large star-to-star scatter\\u000aobserved in the abundances of

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

2006-01-01

25

r-Process Elements in the Milky Way  

Microsoft Academic Search

The origin and distribution of r-process elements in the Milky Way are poorly understood. To unravel the chemical evolution history of the Galaxy, we are working to measure the abundances of europium and other r-process elements in solar-metallicty Galactic thin disk stars. With nearly one thousand S\\/N 100 Keck I HIRES spectra of stars with 0.5 < B-V < 1.5

Kathryn M. G. Peek; G. W. Marcy

2007-01-01

26

The Heaviest Elements: r-Process Abundances In The Galaxy  

Microsoft Academic Search

The origin of r-process elements in the Milky Way is poorly understood. We measure the abundance of europium, an r-process element, in Galactic thin disk stars. With nearly one thousand Keck I HIRES spectra for stars that have 0.5 < B-V < 1.5 and -0.5 < [Fe\\/H] < 0.5, we expect to place strong constraints on the origin of the

Kathryn M. Peek; G. Marcy

2007-01-01

27

Barium from a mini r-process in supernovae  

NASA Technical Reports Server (NTRS)

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

Heymann, D.

1983-01-01

28

Sensitivity studies for the main r process: nuclear masses  

SciTech Connect

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

Aprahamian, A.; Mumpower, M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)] [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Bentley, I. [Department of Chemistry and Physics, St. Mary's College, Notre Dame, IN 46556 (United States)] [Department of Chemistry and Physics, St. Mary's College, Notre Dame, IN 46556 (United States); Surman, R. [Department of Physics and Astronomy, Union College, Schenectady, NY 12308 (United States)] [Department of Physics and Astronomy, Union College, Schenectady, NY 12308 (United States)

2014-04-15

29

R-process in Supernovae and Gamma-Ray Bursts  

SciTech Connect

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

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

2010-05-12

30

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

31

r-process nucleosynthesis in dynamic helium-burning environments  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

32

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

33

r-PROCESS Reaction Rates for the Actinides and Beyond  

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

34

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

35

Rosens (M,R) system in process algebra  

PubMed Central

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

2013-01-01

36

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

37

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

NASA Technical Reports Server (NTRS)

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

Meyer, Bradley S.

1994-01-01

38

Extinct Radioactivities and the R-Process Jet  

NASA Technical Reports Server (NTRS)

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

Cameron, A. G. W.

2001-01-01

39

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

40

24 CFR 235.1220 - Processing section 235(r) mortgages under the direct endorsement program.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Processing section 235(r) mortgages under the direct endorsement...Responsibilities-Refinancing Mortgages Under Section 235(r) of the National Housing Act Eligibility... 235.1220 Processing section 235(r) mortgages under the direct...

2010-04-01

41

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

E-print Network

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

42

?-decay spectroscopy for the r-process nucleosynthesis  

SciTech Connect

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

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

2014-05-09

43

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

SciTech Connect

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

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

1981-06-01

44

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

45

Novel technique for Constraining r-Process (n, ?) Reaction Rates.  

PubMed

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

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

2014-12-01

46

Novel technique for constraining r-process (n,$?$) reaction rates  

E-print Network

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

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

2014-08-27

47

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

PubMed

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

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

2014-12-01

48

MODISTools downloading and processing MODIS remotely sensed data in R  

PubMed Central

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

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

2014-01-01

49

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

50

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

51

Mass measurements along the r-process path at CARIBU  

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

52

The r-process and neutrino-heated supernova ejecta  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

53

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

SciTech Connect

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

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

2012-01-15

54

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

55

Composition Control in the Direct Laser-Deposition Process R.R. UNOCIC and J.N. DuPONT  

E-print Network

Composition Control in the Direct Laser-Deposition Process R.R. UNOCIC and J.N. DuPONT Laser demonstrated[4] that the chemical composition of the deposit can be deter- mined through knowledge dilution agrees very well with the composition determined through direct chemical analy- sis.[4,5] Figure 1

DuPont, John N.

56

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

57

Explorations of the r-Processes: Comparisons between Calculations and Observations of Low-Metallicity Stars  

E-print Network

Abundances of heavier elements (barium and beyond) in many neutron-capture-element-rich halo stars accurately replicate the solar system r-process pattern. However, abundances of lighter neutron-capture elements in these stars are not consistent with the solar system pattern. These comparisons suggest contributions from two distinct types of r-process synthesis events -- a so called main r-process for the elements above the 2nd r-process peak and a weak r-process for the lighter neutron-capture elements. We have performed r-process theoretical predictions to further explore the implications of the solar and stellar observations. We find that the isotopic composition of barium and the elemental Ba/Eu abundance ratios in r-process-rich low metallicity stars can only be matched by computations in which the neutron densities are in the range 23< log n_n < 28, values typical of the main r-process. For r-process conditions that successfully generate the heavy element pattern extending down to A=135, the relative abundance of I129 produced in this mass region appears to be at least 90% of the observed solar value. Finally, in the neutron number density ranges required for production of the observed solar/stellar 3rd r-process-peak (A~200), the predicted abundances of inter-peak element hafnium (Z=72, A~180) follow closely those of 3rd-peak elements and lead. Hf, observable from the ground and close in mass number to the 3rd r-process-peak elements, might also be utilized as part of a new nuclear chronometer pair, Th/Hf, for stellar age determinations.

Karl-Ludwig Kratz; Khalil Farouqi; Bernd Pfeiffer; James W. Truran; Christopher Sneden; John J. Cowan

2007-03-05

58

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

SciTech Connect

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

Shibagaki, S.; Kajino, T. [Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan and National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Chiba, S. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8850 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, IN 46556, U.S.A. and National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2014-05-09

59

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

PubMed

Signaling through the mammalian target of rapamycin, complex 1 (mTORC1), positively regulates the transcription of ribosomal RNA (rRNA) and the synthesis of ribosomal proteins, thereby promoting the complex process of ribosome biogenesis. The major rRNAs are transcribed as a single precursor, which must be processed to create the 5.8S, 18S and 28S rRNAs. We used a new non-radioactive labeling approach to study the effects of rapamycin, an inhibitor of mTORC1, on rRNA synthesis. Rapamycin not only impaired synthesis of new 18S, 28S or 5S rRNA but also induced their decay. This prompted us to examine the effects of rapamycin on rRNA processing. We show that rapamycin also interferes with the processing events that generate 18S and 28S rRNA. rRNA transcription and processing occur in regions of the nucleus known as nucleoli. We find that the mTORC1 components raptor and mTOR are both present in nucleoli, where they may regulate rRNA maturation events. While rapamycin has no effect on overall nucleolar morphology or its proteome, it does induce loss of mTOR and raptor from them. These data show that mTORC1 is located in nucleoli where it acts to regulate events involved in ribosome biogenesis including the maturation of rRNA molecules. PMID:22121221

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

2012-03-01

60

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

SciTech Connect

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

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

2012-03-15

61

Sensitivity studies for r-process nucleosynthesis in three astrophysical scenarios  

E-print Network

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

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

2013-08-31

62

Observations of r- and s-process elements in Population II stars  

E-print Network

The framework for the interpretation of neutron-capture elements observed in Population II stars, established 20-25 years ago, is that these stars primarily exhibit r-process signatures, due to the inefficiency of the s-process at low metallicity. A view developed later that the r-process might be universal, which is to say that the same r-process element ratios would exist at high and low metallicity. However, observations of s-process abundances in low-metallicity environments, and departures from a universal r-process ratio for the lightest neutron-capture elements have required revisions to the framework. Observations indicating the need for and nature of these changes will be presented.

Sean G. Ryan

2002-10-15

63

NUCLEAR PHYSICS: Challenge on the Astrophysical R-Process Calculation with Nuclear Mass Models  

NASA Astrophysics Data System (ADS)

Our understanding of the rapid neutron capture nucleosynthesis process in universe depends on the reliability of nuclear mass predictions. Initiated by the newly developed mass table in the relativistic mean field theory (RMF), we investigate the influence of mass models on the r-process calculations, assuming the same astrophysical conditions. The different model predictions on the so far unreachable nuclei lead to significant deviations in the calculated r-process abundances.

Sun, Bao-Hua; Meng, Jie

2008-07-01

64

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

E-print Network

Laboratory BWR Boiling Water Reactor CERCLA Comprehensive Environmental Response, Compensation and Liability an objective point of view, and no recommendations or endorsements of a S/S process will be finalized

65

EUROPEAN FORESIGHT PROCESSES ON METROLOGY R&D  

Microsoft Academic Search

The background and the results of a first investigation on national foresight processes carried out in European countries, and what we learned from it, are here presented. This work is one of the basic tasks of the European project \\

Attilio Sacconi; Monica Cariola

66

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

67

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

E-print Network

to 7000 tons of hot metal per day. The efficiency of performance of the blast fu~nace is continuously improved and its operation and design improvement is a never ending process. Witness the most recent modifications by the Japanese steel makers who... are integrated facilities, especially in the metals industries. This gives rise to interdependent operations and places a high value on operational reliability. A faulty new process idles many other dependent operations and is financially unaffordable...

Sheneman, R. L.

1979-01-01

68

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

69

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

70

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

E-print Network

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

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

2007-08-13

71

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

72

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

73

International Conference on IEEESignal Processing and Communications R  

E-print Network

submission: February 5, 2010tutorials and invited papers by distinguished researchers from the academia, Bangalore SPCOM 2010 July 18-21, 2010 SPCOM 2010 provides a forum for researchers from academia, research for Communications Systems, Standards and Implementations Coding/Signal Processing in Biology Biological Network

Sharma, Vinod

74

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

SciTech Connect

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

Kratz, K.-L.; Pfeiffer, B. [Max-Planck-Institut fuer Chemie, Otto-Hahn-Institut, D-55128 Mainz (Germany); Farouqi, K. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL60637 (United States); Mashonkina, L. I. [Institute of Astronomy, Russian Academy of Science, RU-119017 Moscow (Russian Federation)

2008-01-24

75

Nanosized carbon forms in the processes o f p r e s s u r e t e m p e r a t u r e -i n d u c e d  

E-print Network

Nanosized carbon forms in the processes o f p r e s s u r e ­ t e m p e r a t u r e - i n d u c e d-resolution transmission electron microscopies. As a result, it has been established that various nanometer-sized carbon species (spherical and coalesced two-core onion-like carbon particles, faceted polyhedral particles

Paris-Sud XI, Université de

76

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

77

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

SciTech Connect

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

Otsuki, K. [Hokkaido University, N10W8, Kita, Sapporo, Hokkaido, Japan 060-0810 (Japan); Burrows, A. [Princeton University, Princeton, NJ 08544 (United States); Martinez-Pinedo, G.; Typel, S.; Langanke, K. [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Matos, M. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2010-06-01

78

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

79

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

80

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

81

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

E-print Network

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

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

2013-08-31

82

R-process Experimental Campaign at the National Superconducting Cyclotron Laboratory  

E-print Network

A JINA/VISTARS r-process campaign was completed at the A1900 Fragment Separator of the National Superconducting Cyclotron Laboratory in the fall of 2005. The purpose of the campaign was the measurement of the beta-decay half-lives and beta-delayed neutron-emission probabilities of different unknown neutron-rich nuclei participating in the r-process. Details of this campaign will be presented.

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

2006-08-27

83

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

84

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

85

Production of All the r-process Nuclides in the Dynamical Ejecta of Neutron Star Mergers  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

86

Processing of Escherichia coli 16S rRNA with bacteriophage lambda leader sequences.  

PubMed Central

To test whether any specific 5' precursor sequences are required for the processing of pre-16S rRNA, constructs were studied in which large parts of the 5' leader sequence were replaced by the coliphage lambda pL promoter and adjacent sequences. Unexpectedly, few full-length transcripts of the rRNA were detected after the pL promoter was induced, implying that either transcription was poor or most of the rRNA chains with lambda leader sequences were unstable. Nevertheless, sufficient transcription occurred to permit the detection of processing by S1 nuclease analysis. RNA transcripts in which 2/3 of the normal rRNA leader was deleted (from the promoter up to the normal RNase III cleavage site) were processed to form the normal 5' terminus. Thus, most of the double-stranded stem that forms from sequences bracketing wild-type 16S pre-rRNA is apparently not required for proper processing; the expression of such modified transcripts, however, must be increased before the efficiency of processing of the 16S rRNA formed can be assessed. Images PMID:2445728

Krych, M; Sirdeshmukh, R; Gourse, R; Schlessinger, D

1987-01-01

87

The yields of r-process elements and chemical evolution of the Galaxy  

E-print Network

The supernova yields of r-process elements are obtained as a function of the mass of their progenitor stars from the abundance patterns of extremely metal-poor stars on the left-side [Ba/Mg]-[Mg/H] boundary with a procedure proposed by Tsujimoto and Shigeyama. The ejected masses of r-process elements associated with stars of progenitor mass $M_{ms}\\leq18M_{\\odot}$ are infertile sources and the SNe II with 20$M_{\\odot}\\leq M_{ms}\\leq 40M_{\\odot}$are the dominant source of r-process nucleosynthesis in the Galaxy. The ratio of these stars 20$M_{\\odot}\\leq M_{ms}\\leq40M_{\\odot}$ with compared to the all massive stars is about $\\sim$18%. In this paper, we present a simple model that describes a star's [r/Fe] in terms of the nucleosynthesis yields of r-process elements and the number of SN II explosions. Combined the r-process yields obtained by our procedure with the scatter model of the Galactic halo, the observed abundance patterns of the metal-poor stars can be well reproduced

Zhe Chen; Jiang Zhang; YanPing Chen; WenYuan Cui; Bo Zhang

2006-08-26

88

Scenarios and the design process in medical application R. Rasoulifar*, G. Thomann, F. Villeneuve  

E-print Network

in medical domain have attracted the design researchers. The design process of medial devices has yet which represent the confrontation between engineering (device design) and medical (usageScenarios and the design process in medical application R. Rasoulifar*, G. Thomann, F. Villeneuve G

Paris-Sud XI, Université de

89

Stochastic Impulsive Systems Driven by Renewal Processes Jo~ao P. Hespanha and Andrew R. Teel  

E-print Network

Stochastic Impulsive Systems Driven by Renewal Processes Jo~ao P. Hespanha and Andrew R. Teel Abstract-- Stochastic impulsive systems are defined by a diffusion process with jumps triggered that guarantee their mean-square stability. As an application, we show that stochastic impulsive systems can

Hespanha, João Pedro

90

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

SciTech Connect

About half of the nuclei heavier than iron observed in nature are produced by the so-called rapid neutron capture process, or r-process, of nucleosynthesis. The identification of the astrophysics site and the specific conditions in which the r-process takes place remains, however, one of the still-unsolved mysteries of modern astrophysics. Another underlying difficulty associated with our understanding of the r-process concerns the uncertainties in the predictions of nuclear properties for the few thousands exotic neutron-rich nuclei involved, for which essentially no experimental data exist. The present paper emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the nuclear structure properties of exotic neutron-rich nuclei as well as their radiative neutron capture rates and their fission probabilities. These quantities are particularly relevant to determine the composition of the matter resulting from the r-process. Both the astrophysics and the nuclear physics difficulties are critically reviewed with special attention paid to the r-process taking place during the decompression of neutron star matter following the merging of two neutron stars.

Goriely, S. [Institut d'Astronomie et d'Astrophysique, CP-226, Universit Libre de Bruxelles, 1050 Brussels (Belgium); Bauswein, A. [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece and Max-Planck-Institut fr Astrophysik, Postfach 1317, 85741 Garching (Germany); Janka, H.-T. [Max-Planck-Institut fr Astrophysik, Postfach 1317, 85741 Garching (Germany); Sida, J.-L.; Lematre, J.-F.; Panebianco, S. [C.E.A. Saclay, Irfu/Service de Physique Nuclaire, 91191 Gif-sur-Yvette (France); Dubray, N.; Hilaire, S. [CEA, DAM, DIF, F-91297 Arpajon (France)

2014-05-02

91

Enrichment of the r-process Element Europium in the Galactic Halo  

E-print Network

We investigate the enrichment of europium, as a representative of r-process elements, in the Galactic halo. In present chemical evolution models, stars are assumed to be formed through shock processes by supernovae (SNe). The enrichment of the interstellar medium is calculated by a one-zone approach. The observed large dispersions in [Eu/Fe] for halo stars, converging with increasing metallicity, can be explained with our models. In addition, the mass range of SNe for the {\\it r}-process site is constrained to be either stars of $8-10 M_\\odot$ or $\\gtrsim 30 M_\\odot$.

Yuhri Ishimaru; Shinya Wanajo

1998-12-03

92

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

93

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

94

P2Y2 R activation by nucleotides promotes skin wound-healing process.  

PubMed

P2Y2 R has been shown to be upregulated in a variety of tissues in response to stress or injury and to mediate tissue regeneration through its ability to activate multiple signalling pathways. This study aimed to investigate the role of P2Y2 R in the wound-healing process and the mechanisms by which P2Y2 R activation promotes wound healing in fibroblasts. The role of P2Y2 R in skin wound healing was examined using a full-thickness skin wound model in wildtype (WT) and P2Y2 R(-/-) mice and an in vitro scratch wound model in control or P2Y2 R siRNA-transfected fibroblasts. WT mice showed significantly decreased wound size compared with P2Y2 R(-/-) mice at day 14 post-wounding, and immunohistochemical analysis showed that a proliferation marker Ki67 and extracellular matrix (ECM)-related proteins VEGF, collagen I, fibronectin and ?-SMA were overexpressed in WT mice, which were reduced in P2Y2 R(-/-) mice. Scratch-wounded fibroblasts increased ATP release, which peaked at 5 min. In addition, scratch wounding increased the level of P2Y2 R mRNA. Activation of P2Y2 R by ATP or UTP enhanced proliferation and migration of fibroblasts in in vitro scratch wound assays and were blocked by P2Y2 R siRNA. Finally, ATP or UTP also increased the levels of ECM-related proteins through the activation of P2Y2 R in fibroblasts. This study suggests that P2Y2 R may be a potential therapeutic target to promote wound healing in chronic wound diseases. PMID:24816122

Jin, Hana; Seo, Jihye; Eun, So Young; Joo, Young Nak; Park, Sang Won; Lee, Jae Heun; Chang, Ki Churl; Kim, Hye Jung

2014-07-01

95

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

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

96

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

97

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

SciTech Connect

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

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

2012-02-20

98

Novel Essential Gene Involved in 16S rRNA Processing in Escherichia coli.  

PubMed

Biogenesis of ribosomes is a complex process mediated by many factors. While its transcription proceeds, ribosomal RNA (rRNA) folds itself into a characteristic three-dimensional structure through interaction with ribosomal proteins, during which its ends are processed. Here, we show that the essential protein YqgF, a RuvC family protein with an RNase-H-like motif, is involved in the processing of pre-16S rRNA during ribosome maturation. Indeed, pre-16S rRNA accumulated in cells of a temperature-sensitive yqgF mutant (yqgF(ts)) cultured at a non-permissive temperature. In addition, purified YqgF was shown to process the 5' end of pre-16S rRNA within 70S ribosomes in vitro. Mass spectrometry analysis of the total proteins in the yqgF(ts) mutant cells showed that the expression of genes containing multiple Shine-Dalgarno-like sequences was observed to be lower than in wild type. These results are interpreted to indicate that YqgF is involved in a novel enzymic activity necessary for the processing of pre-16S rRNA, thereby affecting elongation of translation. PMID:25545592

Kurata, Tatsuaki; Nakanishi, Shinobu; Hashimoto, Masayuki; Taoka, Masato; Yamazaki, Yukiko; Isobe, Toshiaki; Kato, Jun-Ichi

2015-02-27

99

PRIMORDIAL r-PROCESS DISPERSION IN METAL-POOR GLOBULAR CLUSTERS  

SciTech Connect

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

Roederer, Ian U., E-mail: iur@obs.carnegiescience.edu [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

2011-05-01

100

r-Process Abundance Signatures in Metal-Poor Halo Stars  

NASA Astrophysics Data System (ADS)

Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. Recent observations of the r-process-enriched star BD+17 3248 include new abundance determinations for the neutron-capture elements Cd I (Z=48), Lu II (Z = 71) and Os II (Z = 76), the first detections of these elements in metal-poor r-process-enriched halo stars. Combining these and previous observations, we have now detected 32 n-capture elements in BD+17 3248. This is the most of any metal-poor halo star to date. For the most r-process-rich (i.e. [Eu/Fe] ? 1) halo stars, such as CS 22892-052 and BD+17 3248, abundance comparisons show that the heaviest stable n-capture elements (i.e., Ba and above, Z ? 56) are consistent with a scaled solar system r-process abundance distribution. The lighter n-capture element abundances in these stars, however, do not conform to the solar pattern. These comparisons, as well as recent observations of heavy elements in metal-poor globular clusters, suggest the possibility of multiple synthesis mechanisms for the n-capture elements. The heavy element abundance patterns in most metal-poor halo stars do not resemble that of CS 22892-052, but the presence of heavy elements such as Ba in nearly all metal-poor stars without s-process enrichment indicates that r-process enrichment in the early Galaxy is common.

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

2011-08-01

101

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

E-print Network

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.

R. Surman; G. C. McLaughlin; M. Ruffert; H. -Th. Janka; W. R. Hix

2008-03-12

102

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

103

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

104

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, calciumaluminum-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

105

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

E-print Network

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

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

2013-07-01

106

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

PubMed

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

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

107

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

108

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

E-print Network

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

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

2013-09-02

109

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

E-print Network

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

Toshio Suzuki; Takashi Yoshida; Toshitaka Kajino; Takaharu Otsuka

2011-10-18

110

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

PubMed

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

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

2011-05-20

111

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

112

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

113

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

SciTech Connect

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

Ishimaru, Yuhri [Department of Material Science, International Christian University, 3-10-2 Osawa, Mitaka, Tokyo 181-8585 (Japan); Wanajo, Shinya [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Prantzos, Nikos [Institut d'Astrophysique de Paris, UMR7095 CNRS, Univ. P. and M. Curie, 98bis Bd. Arago, 75104 Paris (France)

2014-05-02

114

Nuclear Structure Studies at ISOLDE and their Impact on the Astrophysical r-Process  

E-print Network

The focus of the present review is the production of the heaviest elements in nature via the r-process. A correct understanding and modeling requires the knowledge of nuclear properties far from stability and a detailed prescription of the astrophysical environment. Experiments at CERN/ISOLDE have played a pioneering role in exploring the characteristics of nuclear structure in terms of masses and beta-decay properties. Initial examinations paid attention to far unstable nuclei with magic neutron numbers related to r-process peaks, while present activities are centered on the evolution of shell effects with the distance from the valley of stability. We first show in site-independent applications the effect of both types of nuclear properties on r-process abundances. Then, we explore the results of calculations related to two different `realistic' astrophysical sites, (i) the supernova neutrino wind and (ii) neutron star mergers. We close with a list of remaining theoretical and experimental challenges needed to overcome for a full understanding of the nature of the r-process, and the role CERN/ISOLDE can play in this process.

K. -L. Kratz; B. Pfeiffer; F. -K. Thielemann; W. B. Walters

1999-07-06

115

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

116

r-;:;;  

E-print Network

... s.. $ Cd. I.k $A:I .ft..fS.nu J.·-ICr· l . "...... { 0 " .tWill r: Q) ! (_I)k.,,. I +l~ of -fl. Se..:,s.) "..- I l Ifi\\ r:t clt"..I"~s -to cO ,tL I,,,,,,S,, -= GIG · \\:I If ....... ! I (j) .t....tff'\\'c. S;(~CS Te~t r\\+' , .0 Ie. 2 W\\) I 1- r 2: r :: I,,,,, (t+y~r + ..",+r =,,~.. 1_ Y'" 0It.. 1I\\.......l

Li, Kin-Yin

117

Misregulation of miR-1 processing is associated with heart defects in myotonic dystrophy.  

PubMed

Myotonic dystrophy is an RNA gain-of-function disease caused by expanded CUG or CCUG repeats, which sequester the RNA binding protein MBNL1. Here we describe a newly discovered function for MBNL1 as a regulator of pre-miR-1 biogenesis and find that miR-1 processing is altered in heart samples from people with myotonic dystrophy. MBNL1 binds to a UGC motif located within the loop of pre-miR-1 and competes for the binding of LIN28, which promotes pre-miR-1 uridylation by ZCCHC11 (TUT4) and blocks Dicer processing. As a consequence of miR-1 loss, expression of GJA1 (connexin 43) and CACNA1C (Cav1.2), which are targets of miR-1, is increased in both DM1- and DM2-affected hearts. CACNA1C and GJA1 encode the main calcium- and gap-junction channels in heart, respectively, and we propose that their misregulation may contribute to the cardiac dysfunctions observed in affected persons. PMID:21685920

Rau, Frdrique; Freyermuth, Fernande; Fugier, Charlotte; Villemin, Jean-Philippe; Fischer, Marie-Christine; Jost, Bernard; Dembele, Doulaye; Gourdon, Genevive; Nicole, Annie; Duboc, Denis; Wahbi, Karim; Day, John W; Fujimura, Harutoshi; Takahashi, Masanori P; Auboeuf, Didier; Dreumont, Natacha; Furling, Denis; Charlet-Berguerand, Nicolas

2011-07-01

118

R. Budiu Interpretation-Based Processing 1 Running Head: INTERPRETATION-BASED PROCESSING  

E-print Network

-Based Processing: A Unified Theory of Semantic Sentence Comprehension Ambiguity is one feature of human language such as Lakoff (Lakoff, 1987; Lakoff & Johnson, 1990) or Reddy (1993), language is often shaped by existing, conceptual metaphors. Humans comprehend language not only in the presence of ambiguity or nonliterality

119

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

NASA Astrophysics Data System (ADS)

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

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

120

Processing of the precursors to small nucleolar RNAs and rRNAs requires common components.  

PubMed

The genes encoding the small nucleolar RNA (snoRNA) species snR190 and U14 are located close together in the genome of Saccharomyces cerevisiae. Here we report that these two snoRNAs are synthesized by processing of a larger common transcript. In strains mutant for two 5'-->3' exonucleases, Xrn1p and Rat1p, families of 5'-extended forms of snR190 and U14 accumulate; these have 5' extensions of up to 42 and 55 nucleotides, respectively. We conclude that the 5' ends of both snR190 and U14 are generated by exonuclease digestion from upstream processing sites. In contrast to snR190 and U14, the snoRNAs U18 and U24 are excised from the introns of pre-mRNAs which encode proteins in their exonic sequences. Analysis of RNA extracted from a dbr1-delta strain, which lacks intron lariat-debranching activity, shows that U24 can be synthesized only from the debranched lariat. In contrast, a substantial level of U18 can be synthesized in the absence of debranching activity. The 5' ends of these snoRNAs are also generated by Xrn1p and Rat1p. The same exonucleases are responsible for the degradation of several excised fragments of the pre-rRNA spacer regions, in addition to generating the 5' end of the 5.8S rRNA. Processing of the pre-rRNA and both intronic and polycistronic snoRNAs therefore involves common components. PMID:9488433

Petfalski, E; Dandekar, T; Henry, Y; Tollervey, D

1998-03-01

121

Processing of the Precursors to Small Nucleolar RNAs and rRNAs Requires Common Components  

PubMed Central

The genes encoding the small nucleolar RNA (snoRNA) species snR190 and U14 are located close together in the genome of Saccharomyces cerevisiae. Here we report that these two snoRNAs are synthesized by processing of a larger common transcript. In strains mutant for two 5??3? exonucleases, Xrn1p and Rat1p, families of 5?-extended forms of snR190 and U14 accumulate; these have 5? extensions of up to 42 and 55 nucleotides, respectively. We conclude that the 5? ends of both snR190 and U14 are generated by exonuclease digestion from upstream processing sites. In contrast to snR190 and U14, the snoRNAs U18 and U24 are excised from the introns of pre-mRNAs which encode proteins in their exonic sequences. Analysis of RNA extracted from a dbr1-? strain, which lacks intron lariat-debranching activity, shows that U24 can be synthesized only from the debranched lariat. In contrast, a substantial level of U18 can be synthesized in the absence of debranching activity. The 5? ends of these snoRNAs are also generated by Xrn1p and Rat1p. The same exonucleases are responsible for the degradation of several excised fragments of the pre-rRNA spacer regions, in addition to generating the 5? end of the 5.8S rRNA. Processing of the pre-rRNA and both intronic and polycistronic snoRNAs therefore involves common components. PMID:9488433

Petfalski, Elisabeth; Dandekar, Thomas; Henry, Yves; Tollervey, David

1998-01-01

122

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

123

Controls on Nitrogen Loss Processes in Chesapeake Bay Sediments Andrew R. Babbin* and Bess B. Ward  

E-print Network

Controls on Nitrogen Loss Processes in Chesapeake Bay Sediments Andrew R. Babbin* and Bess B. Ward is increasing as a direct result of anthropogenic nitrogen loading, but the controls on the mechanisms, United States *S Supporting Information ABSTRACT: The flux of fixed nitrogen into the marine environment

Ward, Bess

124

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

E-print Network

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

Solar, Gary S.

125

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

SciTech Connect

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

Kasen, Daniel; Barnes, Jennifer [Department of Physics and Astronomy, University of California, Berkeley, CA 94720 (United States); Badnell, N. R. [Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2013-09-01

126

Alfven Wave-Driven Proto-Neutron Star Winds And R-Process Nucleosynthesis  

E-print Network

We propose magnetic proto-neutron star (PNS) winds driven by \\Alfven waves as well as the neutrino heating as an appropriate site for the r-process nucleosynthesis. \\Alfven waves excited by surface motions of a PNS propagate outwardly, and they heat and accelerate the wind by dissipation. Compared with the wind purely driven by the neutrino heating, larger entropy per baryon and shorter dynamical time scale are achieved, which favors the r-process. We study reasonable cases that a wave amplitude is 10% of \\Alfven speed at the surface to find that a PNS with surface field strength, $\\gtrsim 5\\times 10^{14}$G, gives suitable wind properties for the r-process, provided that dissipation length of the wave is at most $\\sim$ 10 times of the PNS radius. We also compare properties of transcritical and subcritical winds in light of the r-process. We finally discuss possibilities of detections of $\\gamma$-rays from radioactive nuclei and absorption lines due to Ba in supernova remnants which possess magnetars.

Takeru K. Suzuki; Shigehiro Nagataki

2005-06-03

127

It's all about being right: lessons from the R 6 RS process  

Microsoft Academic Search

In the Revised Reports on Scheme up to R5RS, the language could only be changed by unanimous consent. It has been widely believed that any language changes made in this way would clearly be the right thing. Arguably, this process reached its limits with the Revised5 Report on Scheme: Crucial language additions such as modules, records and exceptions had little

Michael Sperber

2009-01-01

128

Neutrino-induced neutron spallation and supernova r-process nucleosynthesis  

E-print Network

In order to explore the consequences of the neutrino irradiation for the supernova r-process nucleosynthesis, we calculate the rates of charged-current and neutral-current neutrino reactions on neutron-rich heavy nuclei, and estimate the average number of neutrons emitted in the resulting spallation. Our results suggest that charged-current $\

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

1996-11-05

129

JAN 163a 39 [1] R.J.R. Back, R. KurkiSuonio; Decentralization of process nets with centralized control, 2nd  

E-print Network

:s:p:q:(wev:DO:q:r))) ?? (b ?? p ?? r) ?? (b ?? :p ?? q ?? r) ) wev:DO:q:r] j f (18c) g [(:b ?? (wev:s:p:(wev:DO:q:r) ?? wlp) for s g (:b ?? (wlp:s:(wlto:DO:p:q:r) ??wlev:s:q:(wlev:DO:(p ?? q):r)) ?? (b ?? q ?? r) ) f (18a) g (:b ?? (wlev

130

R-Process Abundances and Chronometers in Metal-Poor Stars  

E-print Network

Rapid neutron-capture (i.e., r-process) nucleosynthesis calculations, employing internally consistent and physically realistic nuclear physics input (QRPA beta-decay rates and the ETFSI-Q nuclear mass model), have been made. These calculations are compared with ground-based and HST observations of neutron-capture elements in the metal poor halo stars CS 22892--052, HD 115444, HD 122563 and HD 126238. The elemental abundances in all four metal-poor stars are consistent with the solar r-process elemental distribution for the elements Z >/= 56. These results strongly suggest, at least for those elements, that the relative elemental r-process abundances have not changed over the history of the Galaxy. This further suggests that there is one r-process site in the Galaxy, at least for elements Z >/= 56. Employing the observed stellar abundances of stable elements, in conjunction with the solar r-process abundances to constrain the calculations, predictions for the zero decay-age abundances of the radioactive elements Th and U are made. We compare these (least-squares-fit ETFSI-Q) predictions with newly derived observational values in three very metal-poor halo stars: HD 115444, CS 22892--052 and HD 122563. Within the observational errors the observed ratio of [Th/Eu] is the same in both CS 22892--052 and HD 115444. Comparing with the theoretical ratio suggests an average age of these two very metal poor stars to be approximately 15.6 +/- 4.6 Gyr, consistent with earlier radioactive age estimates and recent globular and cosmological age estimates.

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

1999-04-09

131

r-Process nucleosynthesis: Present status and future experiments at the FRS and ESR  

NASA Astrophysics Data System (ADS)

No astrophysical process other than the rapid neutron capture process (r process) is used more often to motivate the necessity of the new-generation radioactive beam facilities with higher beam intensities. In the dawn of these facilities (RIBF at RIKEN, FRIB at Michigan State University, and FAIR in Darmstadt) experiments carried out at the presently existing facilities mark a transition between the past and the future. Two such facilities are the Fragment Separator (FRS) and Experimental Storage Ring (ESR) at the GSI Helmholtzzentrum fr Schwerionenforschung in Darmstadt. Up to now one could only scratch the regions where the r process takes place-with the exception of the N=126 region, which remains an experimental terra incognita. Owing to the upgrade of the GSI accelerator and to the development of new highly sensitive and efficient detection techniques in view of the future FAIR facility, planned experiments at the FRS and ESR aim at filling this gap, approaching the r-process path also at N=126.

Dillmann, Iris; Litvinov, Yuri A.

2011-04-01

132

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

133

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

SciTech Connect

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

Spielberger, L.; Klein, J.

1981-05-01

134

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

PubMed Central

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

Plewnia, Christian; Wildgruber, Dirk

2014-01-01

135

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

SciTech Connect

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

Shibagaki, S.; Kajino, T. [Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan and National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Chiba, S. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8850 (Japan); Lorusso, G.; Nishimura, S. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, IN 46556 (United States)

2014-05-02

136

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

137

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

PubMed

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

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

2013-01-01

138

Rok1p is a putative RNA helicase required for rRNA processing.  

PubMed Central

The synthesis of ribosomes involves many small nucleolar ribonucleoprotein particles (snoRNPs) as transacting factors. Yeast strains lacking the snoRNA, snR10, are viable but are impaired in growth and delayed in the early pre-rRNA cleavages at sites A0, A1, and A2, which lead to the synthesis of 18S rRNA. The same cleavages are inhibited by genetic depletion of the essential snoRNP protein Gar1p. Screens for mutations showing synthetic lethality with deletion of the SNR10 gene or with a temperature-sensitive gar1 allele both identified the ROK1 gene, encoding a putative, ATP-dependent RNA helicase of the DEAD-box family. The ROK1 gene is essential for viability, and depletion of Rok1p inhibits pre-rRNA processing at sites A0, A1, and A2, thereby blocking 18S rRNA synthesis. Indirect immunofluorescence by using a ProtA-Rok1p construct shows the protein to be predominantly nucleolar. These results suggest that Rok1p is required for the function of the snoRNP complex carrying out the early pre-rRNA cleavage reactions. PMID:9154839

Venema, J; Bousquet-Antonelli, C; Gelugne, J P; Caizergues-Ferrer, M; Tollervey, D

1997-01-01

139

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

SciTech Connect

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

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

2012-05-01

140

INFERENCES FROM OBLIQUE IMPACT CRATERS ABOUT THE ROLE OF THE ATMOSPHERE AND SUBSURFACE VOLATILES IN THE IMPACT CRATERING PROCESS ON MARS R. R. Herrick,  

E-print Network

INFERENCES FROM OBLIQUE IMPACT CRATERS ABOUT THE ROLE OF THE ATMOSPHERE AND SUBSURFACE VOLATILES IN THE IMPACT CRATERING PROCESS ON MARS R. R. Herrick, Geophysical Institute, University of Alaska Fairbanks of the ejecta blankets from Martian low-angle impact craters with those on Venus, the moon, and from small

Herrick, Robert R.

141

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 during the creation of the SoNaR Corpus. Based on recent developments in traditional corpus compiling and new web harvesting approaches, SoNaR is designed to contain 500 million words, balanced over 36 text

Tilburg, Universiteit van

142

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

143

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

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

144

?-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.; Tan, J. L.; Corts, G.; Agramunt, J.; Algora, A.; Ameil, F.; Ayyad, Y.; Benlliure, J.; Bowry, M.; Calvio, F.; Cano-Ott, D.; Davinson, T.; Dillmann, I.; Estrade, A.; Evdokimov, A.; Faestermann, T.; Farinon, F.; Galaviz, D.; Garca-Rios, A.; Geissel, H.; Gelletly, W.; Gernhuser, R.; Gmez-Hornillos, M. B.; Guerrero, C.; Heil, M.; Hinke, C.; Knbel, R.; Kojouharov, I.; Kurcewicz, J.; Kurz, N.; Litvinov, Y.; Maier, L.; Marganiec, J.; Marta, M.; Martnez, T.; Montes, F.; Mukha, I.; Napoli, D. R.; Nociforo, C.; Paradela, C.; Pietri, S.; Podolyk, 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

145

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

SciTech Connect

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

Caballero-Folch, R.; Cortes, G.; Calvino, F.; Gomez-Hornillos, M. B.; Riego, A. [INTE-DFEN, Universitat Politecnica de Catalunya, Barcelona (Spain); Domingo-Pardo, C.; Tain, J. L.; Agramunt, J.; Rubio, B. [IFIC, CSIC-University of Valencia, Valencia (Spain); Algora, A. [IFIC, CSIC-University of Valencia, Valencia (Spain) and Inst. Nucl. Research, Debrecen (Hungary); Ameil, F.; Farinon, F.; Heil, M.; Knoebel, R.; Kojouharov, I.; Kurcewicz, J.; Kurz, N.; Litvinov, Y.; Mukha, I.; Nociforo, C. [GSI, Darmstadt (Germany); and others

2013-06-10

146

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

147

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

148

R-process nucleosynthesis in the high-entropy supernova bubble  

Microsoft Academic Search

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

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

1992-01-01

149

The spectrum of Canopus. III - Abundances of r- and s-process elements  

Microsoft Academic Search

A careful search has been made for lines of elements heavier than the iron peak in the spectrum of Canopus, mainly using high signal-to-noise spectra in the near ultraviolet. The abundances of 21 heavy r- and s-process elements in Canopus have been determined from the equivalent widths of the lines identified. The results show that Canopus has an essentially solar

S. E. Reynolds; J. B. Hearnshaw; P. L. Cottrell

1988-01-01

150

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

151

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

PubMed Central

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

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

2014-01-01

152

The study of s-process nucleosynthesis based on barium stars, CEMP-s and CEMP-r/s stars  

E-print Network

In order to get a broader view of the s-process nucleosynthesis we study the abundance distribution of heavy elements of 35 barium stars and 24 CEMP-stars, including nine CEMP-s stars and 15 CEMP-r/s stars. The similar distribution of [Pb/hs] between CEMP-s and CEMP-r/s stars indicate that the s-process material of both CEMP-s and CEMP-r/s stars should have a uniform origin, i.e. mass transfer from their predominant AGB companions. For the CEMP-r/s stars, we found that the r-process should provide similar proportional contributes to the second s-peak and the third s-peak elements, and also be responsible for the higher overabundance of heavy elements than those in CEMP-s stars. Which hints that the r-process origin of CEMP-r/s stars should be closely linked to the main r-process. The fact that some small $r$ values exist for both barium and CEMP-s stars, implies that the single exposure event of the s-process nucleosynthesis should be general in a wide metallicity range of our Galaxy. Based on the relation be...

Cui, Wenyuan; Geng, Yuanyuan; Zhang, Caixia; Meng, Xiaoying; Shao, Lang; Zhang, Bo

2013-01-01

153

The History of R-Process Enrichment in the Milky Way  

E-print Network

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

Shen, Sijing; Ramirez-Ruiz, Enrico; Madau, Piero; Mayer, Lucio; Guedes, Javiera

2014-01-01

154

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

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

155

Planar Reflective Phaser and Synthesis for Radio Analog Signal Processing (R-ASP)  

E-print Network

A planar reflective phaser based on an open-ended edge-coupled-line structure is proposed. This phaser is the first reported phaser that combines the benefits of high resolution, inherent to cross-coupled resonator reflective phasers, and of compactness, inherent to planar circuits. A 4-ns swing 4.9-5.5 GHz quadratic phase (linear group delay) 4th-order microstrip phaser is synthesized and experimentally demonstrated. Given its advantages, this phaser may find vast applications in Radio Analog Signal Processing (R-ASP) systems.

Zou, Lianfeng; Caloz, Christophe

2014-01-01

156

Novel technique for constraining r-process (n,$\\gamma$) reaction rates  

E-print Network

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

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

2014-01-01

157

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

Microsoft Academic Search

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

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

2010-01-01

158

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

E-print Network

1154 D. R. Warren et al. Copyright © 2007 John Wiley & Sons, Ltd. Earth Surf. Process. Landforms 32, 1154­1163 (2007) DOI: 10.1002/esp Earth Surface Processes and Landforms Earth Surf. Process. Landforms.interscience.wiley.com) DOI: 10.1002/esp.1548 Forest age, wood and nutrient dynamics in headwater streams of the Hubbard Brook

Hall Jr., Robert O.

159

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

NASA Astrophysics Data System (ADS)

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

Van Schelt, Jonathon A.

160

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

NASA Astrophysics Data System (ADS)

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

Roederer, Ian

2012-10-01

161

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

SciTech Connect

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

Not Available

2005-09-01

162

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

NASA Astrophysics Data System (ADS)

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

van de Voort, Freeke; Quataert, Eliot; Hopkins, Philip F.; Kere, Duan; Faucher-Gigure, Claude-Andr

2015-02-01

163

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

SciTech Connect

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

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

2006-01-01

164

Elevated p53 promotes the processing of miR-18a to decrease estrogen receptor-? in female hepatocellular carcinoma.  

PubMed

The estrogen pathway has long been implicated as a tumor protector in female hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Our previous study identified that estrogen receptor alpha (ER?) protein is downregulated in 60% of female HCC cases, via a miR-18a elevation mediated suppression of ER? translation. This study aims to delineate the mechanism underlying the upregulation of miR-18a in female HCC. The analysis of 77 female HCC specimens revealed that miR-18a levels were associated with pre-miR-18a rather than pri-miR-18a levels, suggesting an enhanced processing of pri- to pre-miR-18a. Among a panel of factors involved in microRNA processing, p53 was identified as a novel regulator for miR-18a maturation process. Knockdown of p53 by si-RNA decreased the level of miR-18a, whereas overexpression of either wild-type or mutant p53 increased its level. The association between the elevation of miR-18a and the accumulation of p53, mainly caused by somatic mutations, was confirmed in the clinical specimens of HBV-related female HCC. By analyzing the association with clinicopathological features, activation of this p53/miR-18a pathway mainly occurs in younger or noncirrhosis female HCC patients and associated with a trend of worse overall survival. Therefore, this study demonstrated a novel function of elevated/mutant p53 in regulating the amount of ER? protein through its promoting the biogenesis of miR-18a, which could lead to decrease the tumor-protective function of the estrogen pathway in female hepatocarcinogenesis. PMID:24975878

Li, Chiao-Ling; Yeh, Kun-Huei; Liu, Wan-Hsin; Chen, Chi-Ling; Chen, Ding-Shinn; Chen, Pei-Jer; Yeh, Shiou-Hwei

2015-02-15

165

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

SciTech Connect

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

Hirayama, Y.; Watanabe, Y. X.; Imai, N.; Ishiyama, H.; Jeong, S. C.; Miyatake, H.; Oyaizu, M. [Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Kim, Y. H. [Seoul National University, Seoul 151-742 (Korea, Republic of); Mukai, M.; Kimura, S. [Tsukuba University, Ibaraki 305-0006 (Japan)

2014-05-02

166

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

167

tgp: An R Package for Bayesian Nonstationary, Semiparametric Nonlinear Regression and Design by Treed Gaussian Process Models  

Microsoft Academic Search

The tgp package for R is a tool for fully Bayesian nonstationary, semiparametric nonlinear regression and design by treed Gaussian processes with jumps to the limiting linear model. Special cases also implemented include Bayesian linear models, linear CART, stationary separable and isotropic Gaussian processes. In addition to inference and posterior prediction, the package supports the (sequential) design of experiments under

Robert B. Gramacy

2007-01-01

168

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

E-print Network

, 1990) has waned in the face of consumer resistance to the use of genetically modified organisms in food1 Chapter for R. Rama (Ed.), Innovation in the food and drink processing industry, Haworth Press Inc, N.Y. Biotech Innovation in Europe's Food and Drink Processing Industry: Promise, Barriers

Paris-Sud XI, Université de

169

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

NASA Astrophysics Data System (ADS)

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

Lascar, Daniel David

170

R-Process Nucleosynthesis In Neutrino-Driven Winds From A Typical Neutron Star With M = 1.4 Msun  

E-print Network

We study the effects of the outer boundary conditions in neutrino-driven winds on the r-process nucleosynthesis. We perform numerical simulations of hydrodynamics of neutrino-driven winds and nuclear reaction network calculations of the r-process. As an outer boundary condition of hydrodynamic calculations, we set a pressure upon the outermost layer of the wind, which is approaching toward the shock wall. Varying the boundary pressure, we obtain various asymptotic thermal temperature of expanding material in the neutrino-driven winds for resulting nucleosynthesis. We find that the asymptotic temperature slightly lower than those used in the previous studies of the neutrino-driven winds can lead to a successful r-process abundance pattern, which is in a reasonable agreement with the solar system r-process abundance pattern even for the typical proto-neutron star mass Mns ~ 1.4 Msun. A slightly lower asymptotic temperature reduces the charged particle reaction rates and the resulting amount of seed elements and lead to a high neutron-to-seed ratio for successful r-process. This is a new idea which is different from the previous models of neutrino-driven winds from very massive (Mns ~ 2.0 Msun) and compact (Rns ~ 10 km) neutron star to get a short expansion time and a high entropy for a successful r-process abundance pattern. Although such a large mass is sometimes criticized from observational facts on a neutron star mass, we dissolve this criticism by reconsidering the boundary condition of the wind. We also explore the relation between the boundary condition and neutron star mass, which is related to the progenitor mass, for successful r-process.

M. Terasawa; K. Sumiyoshi; S. Yamada; H. Suzuki; T. Kajino

2002-06-18

171

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

172

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

E-print Network

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

Foulger, G. R.

173

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

E-print Network

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

Tsujimoto, Takuji

2014-01-01

174

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

NASA Technical Reports Server (NTRS)

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

Rogers, Jan R.

1998-01-01

175

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

176

Near-UV Observations of HD221170: New Insights into the Nature of r-Process-Rich Stars  

E-print Network

Employing high resolution spectra obtained with the near-UV sensitive detector on the Keck I HIRES, supplemented by data obtained with the McDonald Observatory 2-d coude, we have performed a comprehensive chemical composition analysis of the bright r-process-rich metal-poor red giant star HD221170. Analysis of 57 individual neutral and ionized species yielded abundances for a total of 46 elements and significant upper limits for an additional five. Model stellar atmosphere parameters were derived with the aid of ~200 Fe-peak transitions. From more than 350 transitions of 35 neutron-capture (Z > 30) species, abundances for 30 neutron-capture elements and upper limits for three others were derived. Utilizing 36 transitions of La, 16 of Eu, and seven of Th, we derive ratios of log epsilon(Th/La) = -0.73 (sigma = 0.06) and log epsilon(Th/Eu) = -0.60 (sigma = 0.05), values in excellent agreement with those previously derived for other r-process-rich metal-poor stars such as CS22892-052, BD+17 3248, and HD115444. Based upon the Th/Eu chronometer, the inferred age is 11.7 +/- 2.8 Gyr. The abundance distribution of the heavier neutron-capture elements (Z >= 56) is fit well by the predicted scaled solar system r-process abundances, as also seen in other r-process-rich stars. Unlike other r-process-rich stars, however, we find that the abundances of the lighter neutron-capture elements (37 < Z < 56) in HD221170 are also statistically in better agreement with the abundances predicted for the scaled solar r-process pattern.

Inese I. Ivans; Jennifer Simmerer; Christopher Sneden; James E. Lawler; John J. Cowan; Roberto Gallino; Sara Bisterzo

2006-04-08

177

An Extention of Profit Sharing to Partially Observable Markov Decision Processes : Proposition of PS-r* and its Evaluation  

NASA Astrophysics Data System (ADS)

We know the rationality theorem of Profit Sharing(PS) [Miyazaki 94, Miyazaki 99b] and the Rational Policy Making algorithm(RPM) [Miyazaki 99a] to guarantee the rationality in a typical class of Partially Observable Markov Decision Processes (POMDPs). In this paper, we focus on the whole class of POMDPs and propose PS-r that is an algorithm connected PS and RPM with random selection. In the first, we have analyzed the behavior of PS-r. We have derived that the maximum value of the step to get a reward by PS-r divided by that of random selection is

({\\Large r\\frac{(1+\\frac{M-1}{r})^n}{M^n}}) where n
is the maximum number of state that senses same state due to the agent's sensory limitation and M is the number of actions. Furthermore, we propose PS-r* that can improve the behavior of PS-r. Through numerical examples, we conform the effectiveness of PS-r*.

Miyazaki, Kazuteru; Kobayashi, Shigenobu

178

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

SciTech Connect

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

Sneden, Christopher [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Lawler, James E.; Den Hartog, Elizabeth A. [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); Ivans, Inese I. [Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101 (United States)], E-mail: chris@verdi.as.utexas.edu, E-mail: jelawler@wisc.edu, E-mail: eadenhar@wisc.edu, E-mail: cowan@nhn.ou.edu, E-mail: iii@ociw.edu

2009-05-15

179

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

E-print Network

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

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

2009-01-01

180

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

E-print Network

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

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

2009-06-30

181

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

182

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

NASA Astrophysics Data System (ADS)

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

Liu, Pang-Lo; Tsai, Chih-Hung

183

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

184

Vascular remodeling process in pulmonary arterial hypertension, with focus on miR-204 and miR-126 (2013 Grover Conference series)  

PubMed Central

Abstract Pulmonary arterial hypertension (PAH) is a vascular remodeling disease characterized primarily by increased proliferation and resistance to apoptosis in distal pulmonary arteries. Previous literature has demonstrated that the transcription factors NFAT (nuclear factor of activated T cells) and HIF-1? (hypoxia inducible factor 1?) are extensively involved in the pathogenesis of this disease and, more recently, has implicated STAT3 (signal transducer and activator of transcription 3) in their activation. Novel research shows that miR-204, a microRNA recently found to be notably downregulated through induction of PARP-1 (poly [ADP-ribose] polymerase 1) by excessive DNA damage in PAH, inhibits activation of STAT3. Contemporary research also indicates systemic impairment of skeletal muscle microcirculation in PAH and attributes this to a debilitated vascular endothelial growth factor pathway resulting from reduced miR-126 expression in endothelial cells. In this review, we focus on recent research implicating miR-204 and miR-126 in vascular remodeling processes, data that allow a better understanding of PAH molecular pathways and constitute a new hope for future therapy. PMID:25006436

2014-01-01

185

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

186

Electromagnetic counterparts of compact object mergers powered by the radioactive decay of r-process nuclei  

NASA Astrophysics Data System (ADS)

The most promising astrophysical sources of kHz gravitational waves (GWs) are the inspiral and merger of binary neutron star(NS)/black hole systems. Maximizing the scientific return of a GW detection will require identifying a coincident electromagnetic (EM) counterpart. One of the most likely sources of isotropic EM emission from compact object mergers is a supernova-like transient powered by the radioactive decay of heavy elements synthesized in ejecta from the merger. We present the first calculations of the optical transients from compact object mergers that self-consistently determine the radioactive heating by means of a nuclear reaction network; using this heating rate, we model the light curve with a one-dimensional Monte Carlo radiation transfer calculation. For an ejecta mass ~10-2Msolar (10-3Msolar) the resulting light-curve peaks on a time-scale ~1d at a V-band luminosity ?L? ~ 3 1041 (1041)ergs-1 [MV = -15(-14)] this corresponds to an effective `f' parameter ~3 10-6 in the Li-Paczynski toy model. We argue that these results are relatively insensitive to uncertainties in the relevant nuclear physics and to the precise early-time dynamics and ejecta composition. Since NS merger transients peak at a luminosity that is a factor of ~103 higher than a typical nova, we propose naming these events `kilo-novae'. Because of the rapid evolution and low luminosity of NS merger transients, EM counterpart searches triggered by GW detections will require close collaboration between the GW and astronomical communities. NS merger transients may also be detectable following a short-duration gamma-ray burst or `blindly' with present or upcoming optical transient surveys. Because the emission produced by NS merger ejecta is powered by the formation of rare r-process elements, current optical transient surveys can directly constrain the unknown origin of the heaviest elements in the Universe.

Metzger, B. D.; Martnez-Pinedo, G.; Darbha, S.; Quataert, E.; Arcones, A.; Kasen, D.; Thomas, R.; Nugent, P.; Panov, I. V.; Zinner, N. T.

2010-08-01

187

STELLAR SOURCES FOR HEAVY r-PROCESS NUCLEI Y.-Z. Qian1  

E-print Network

the stars were formed but must rep- resent very local contamination from binary companions. Further evidence assume that the bulk of the heavy r-nuclei are produced in AIC events, then these events would have of an essentially bare neutron star for the production of heavy r-nuclei and the proposed role of AIC events

Faraon, Andrei

188

Effects of Charge Transfer on the ESIPT Process in Methyl 5-R-Salicylates.  

PubMed

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

Cataln, J

2015-02-12

189

R&D activities in airborne SAR image processing\\/analysis at Lockheed Martin Canada  

Microsoft Academic Search

We give an overview of some R&D projects in SAR imagery at Lockheed Martin Canada. These projects are motivated by airborne surveillance applications such as the landmass and coastal surveillance missions of the Canadian CP-140 (Aurora) aircraft. The activities reviewed here are: (1) R&D supports to CP-140 Spotlight SAR upgrade, (2) fast multiresolution prescreening filter for CFAR detection, (3) comparison

Langis Gagnon; H. Oppenheim; Pierre Valin

1998-01-01

190

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

NASA Astrophysics Data System (ADS)

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

Wu, Xuerui; Jin, Shuanggen

2014-11-01

191

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

192

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

NASA Astrophysics Data System (ADS)

Context: .Barium stars show enhanced abundances for the slow neutron capture (s-process) heavy elements, so they are suitable objects for studying s-process elements. Aims: .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. Methods: .The abundances of the sample stars were compared to those of normal stars, thus identifying the fraction relative to the main component of the s-process. Results: .The fittings of the ? N 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 the observed data well, whereas a single neutron exposure provides a better fit for others. Conclusions: .The comparison of 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, so barium stars also seemed to be enriched in r-elements, although to a lower degree than s-elements. No dependence on luminosity classes was found in the abundance-ratio behaviour among the dwarfs and giants of the sample of barium stars.

Allen, D. M.; Barbuy, B.

2006-08-01

193

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

E-print Network

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

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

2004-09-22

194

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...

195

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

196

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 (Etvs) 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

197

Detection of low Eu abundances in extremely metal-poor stars and the origin of r-process elements  

E-print Network

We report abundance analyses of three extremely metal-poor stars with [Fe/H] $\\lesssim -3$, using the Subaru High Dispersion Spectrograph (HDS). All are found to have sub-solar values of [Eu/Fe]. Comparison with our chemical evolution model of the Galactic halo implies the dominant source of Eu to be the low-mass end of the supernova mass range. Future studies of stars with low Eu abundances will be important to determine the r-process site.

Yuhri Ishimaru; Shinya Wanajo; Wako Aoki; Sean G. Ryan

2003-11-06

198

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

Microsoft Academic Search

We have derived new abundances of the rare earth elements Pr, Dy, Tm, Yb, and Lu for the solar photosphere and for five very metal-poor, neutron-capture r-process-rich giant stars. The photospheric values for all five elements are in good agreement with meteoritic abundances. For the low-metallicity sample, these abundances have been combined with new Ce abundances from a companion paper,

Christopher Sneden; James E. Lawler; John J. Cowan; Inese I. Ivans; Elizabeth A. Den Hartog; Inese I

2009-01-01

199

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

200

R&D activities in airborne SAR image processing/analysis at Lockheed Martin Canada  

NASA Astrophysics Data System (ADS)

We give an overview of some R&D projects in SAR imagery at Lockheed Martin Canada. These projects are motivated by airborne surveillance applications such as the landmass and coastal surveillance missions of the Canadian CP-140 (Aurora) aircraft. The activities reviewed here are: (1) R&D supports to CP-140 Spotlight SAR upgrade, (2) fast multiresolution prescreening filter for CFAR detection, (3) comparison of traditional and wavelet-based speckle filters and (4) high-level ship classification in high-resolution SAR imagery.

Gagnon, Langis; Oppenheim, H.; Valin, Pierre

1998-12-01

201

Assembly of Saccharomyces cerevisiae 60S ribosomal subunits: role of factors required for 27S pre-rRNA processing.  

PubMed

The precise functions of most of the ?200 assembly factors and 79 ribosomal proteins required to construct yeast ribosomes in vivo remain largely unexplored. To better understand the roles of these proteins and the mechanisms driving ribosome biogenesis, we examined in detail one step in 60S ribosomal subunit assembly-processing of 27SA(3) pre-rRNA. Six of seven assembly factors required for this step (A(3) factors) are mutually interdependent for association with preribosomes. These A(3) factors are required to recruit Rrp17, one of three exonucleases required for this processing step. In the absence of A(3) factors, four ribosomal proteins adjacent to each other, rpL17, rpL26, rpL35, and rpL37, fail to assemble, and preribosomes are turned over by Rat1. We conclude that formation of a neighbourhood in preribosomes containing the A(3) factors establishes and maintains stability of functional preribosomes containing 27S pre-rRNAs. In the absence of these assembly factors, at least one exonuclease can switch from processing to turnover of pre-rRNA. PMID:21926967

Sahasranaman, Aarti; Dembowski, Jill; Strahler, John; Andrews, Philip; Maddock, Janine; Woolford, John L

2011-10-01

202

Assembly of Saccharomyces cerevisiae 60S ribosomal subunits: role of factors required for 27S pre-rRNA processing  

PubMed Central

The precise functions of most of the ?200 assembly factors and 79 ribosomal proteins required to construct yeast ribosomes in vivo remain largely unexplored. To better understand the roles of these proteins and the mechanisms driving ribosome biogenesis, we examined in detail one step in 60S ribosomal subunit assemblyprocessing of 27SA3 pre-rRNA. Six of seven assembly factors required for this step (A3 factors) are mutually interdependent for association with preribosomes. These A3 factors are required to recruit Rrp17, one of three exonucleases required for this processing step. In the absence of A3 factors, four ribosomal proteins adjacent to each other, rpL17, rpL26, rpL35, and rpL37, fail to assemble, and preribosomes are turned over by Rat1. We conclude that formation of a neighbourhood in preribosomes containing the A3 factors establishes and maintains stability of functional preribosomes containing 27S pre-rRNAs. In the absence of these assembly factors, at least one exonuclease can switch from processing to turnover of pre-rRNA. PMID:21926967

Sahasranaman, Aarti; Dembowski, Jill; Strahler, John; Andrews, Philip; Maddock, Janine; Woolford, John L

2011-01-01

203

Ribosomal protein L35 is required for 27SB pre-rRNA processing in Saccharomyces cerevisiae  

PubMed Central

Ribosome synthesis involves the concomitance of pre-rRNA processing and ribosomal protein assembly. In eukaryotes, this is a complex process that requires the participation of specific sequences and structures within the pre-rRNAs, at least 200 trans-acting factors and the ribosomal proteins. There is little information on the function of individual 60S ribosomal proteins in ribosome synthesis. Herein, we have analysed the contribution of ribosomal protein L35 in ribosome biogenesis. In vivo depletion of L35 results in a deficit in 60S ribosomal subunits and the appearance of half-mer polysomes. Pulse-chase, northern hybridization and primer extension analyses show that processing of the 27SB to 7S pre-rRNAs is strongly delayed upon L35 depletion. Most likely as a consequence of this, release of pre-60S ribosomal particles from the nucleolus to the nucleoplasm is also blocked. Deletion of RPL35A leads to similar although less pronounced phenotypes. Moreover, we show that L35 assembles in the nucleolus and binds to early pre-60S ribosomal particles. Finally, flow cytometry analysis indicated that L35-depleted cells mildly delay the G1 phase of the cell cycle. We conclude that L35 assembly is a prerequisite for the efficient cleavage of the internal transcribed spacer 2 at site C2. PMID:20392820

Babiano, Reyes; de la Cruz, Jess

2010-01-01

204

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

205

Evidence of Multiple r-Process Sites in the Early Galaxy: New Observations of CS 22892-052  

E-print Network

First results are reported of a new abundance study of neutron-capture elements in the ultra-metal-poor (UMP; [Fe/H] = -3.1) halo field giant star CS 22892-052. Using new high resolution, high signal-to-noise spectra, abundances of more than 30 neutron-capture elements (Z>30) have been determined. Six elements in the 40=56) stable neutron-capture elements in CS 22892-052 match well the scaled solar system r-process abundance distribution. From the observed Th abundance, an average age of ~= 16 +/- 4 Gyr is derived for cs22892-052, consistent with the lower age limit of ~= 11 Gyr derived from the upper limit on the U abundance. The concordance of scaled solar r-process and CS 22892-052 abundances breaks down for the lighter neutron-capture elements, supporting previous suggestions that different r-process production sites are responsible for lighter and heavier neutron-capture elements.

Christopher Sneden; John J. Cowan; Inese I. Ivans; George M. Fuller; Scott Burles; Timothy C. Beers; James E. Lawler

2000-03-07

206

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

ERIC Educational Resources Information Center

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

Perspectives in Peer Programs, 2007

2007-01-01

207

Comparative study of the bioconversion process using R-(+)- and S-(-)-limonene as substrates for Fusarium oxysporum 152B.  

PubMed

This study compared the bioconversion process of S-(-)-limonene into limonene-1,2-diol with the already established biotransformation of R-(+)-limonene into ?-terpineol using the same biocatalyst in both processes, Fusarium oxysporum 152B. The bioconversion of the S-(-)-isomer was tested on cell permeabilisation under anaerobic conditions and using a biphasic system. When submitted to permeabilisation trials, this biocatalyst has shown a relatively high resistance; still, no production of limonene-1,2-diol and a loss of activity of the biocatalyst were observed after intense cell treatment, indicating a complete loss of cell viability. Furthermore, the results showed that this process can be characterised as an aerobic system that was catalysed by limonene-1,2-epoxide hydrolase, had an intracellular nature and was cofactor-dependent because the final product was not detected by an anaerobic process. Finally, this is the first report to characterise the bioconversion of R-(+)- and S-(-)-limonene by cellular detoxification using ultra-structural analysis. PMID:25529726

Molina, Gustavo; Bution, Murillo L; Bicas, Juliano L; Dolder, Mary Anne Heidi; Pastore, Glucia M

2015-05-01

208

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

Microsoft Academic Search

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

J. Van den Bergh

2010-01-01

209

EVALUATION OF DIFFERENT SIGNAL PROCESSING OPTIONS IN UNILATERAL AND BILATERAL COCHLEAR FREEDOM IMPLANT RECIPIENTS USING R-SPACE 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 recipients 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

210

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

PubMed

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

Matsunaga, Kengo; Kubota, Kengo; Harada, Hideki

2014-12-10

211

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

PubMed Central

Eukaryotic communities involved in sewage treatment processes have been investigated by morphological identification, but have not yet been well-characterized using molecular approaches. In the present study, eukaryotic communities were characterized by constructing 18S rRNA gene clone libraries. The phylogenetic affiliations of a total of 843 clones were Alveolata, Fungi, Rhizaria, Euglenozoa, Stramenopiles, Amoebozoa, and Viridiplantae as protozoans and Rotifera, Gastrotricha, and Nematoda as metazoans. Sixty percent of the clones had <97% sequence identity to described eukaryotes, indicating the greater diversity of eukaryotes than previously recognized. A core OTU closely related to Epistylis chrysemydis was identified, and several OTUs were shared by 48 libraries. Members of the uncultured lineage LKM11 in Cryptomycota were predominant fungi in sewage treatment processes. This comparative study represents an initial step in furthering understanding of the diversity and role of eukaryotes in sewage treatment processes.

Matsunaga, Kengo; Kubota, Kengo; Harada, Hideki

2014-01-01

212

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

213

3D VISUALIZATION OF CONSTRUCTION PROCESSES AND Vineet R. Kamat1  

E-print Network

of construction process modelling (e.g. STROBOSCOPE), the Visualization/Animation aspect has mainly focused by a variety of simulation software tools such as STROBOSCOPE, which is currently being used to test the system

Kamat, Vineet R.

214

24 CFR 235.1220 - Processing section 235(r) mortgages under the direct endorsement program.  

Code of Federal Regulations, 2013 CFR

...mortgage must meet for the direct endorsement program are contained...must be originated through direct endorsement processing...requirements in accordance with the instructions contained in a handbook or...mortgagees approved for the direct endorsement procedure....

2013-04-01

215

24 CFR 235.1220 - Processing section 235(r) mortgages under the direct endorsement program.  

Code of Federal Regulations, 2014 CFR

...mortgage must meet for the direct endorsement program are contained...must be originated through direct endorsement processing...requirements in accordance with the instructions contained in a handbook or...mortgagees approved for the direct endorsement procedure....

2014-04-01

216

24 CFR 235.1220 - Processing section 235(r) mortgages under the direct endorsement program.  

Code of Federal Regulations, 2011 CFR

...mortgage must meet for the direct endorsement program are contained...must be originated through direct endorsement processing...requirements in accordance with the instructions contained in a handbook or...mortgagees approved for the direct endorsement procedure....

2011-04-01

217

24 CFR 235.1220 - Processing section 235(r) mortgages under the direct endorsement program.  

Code of Federal Regulations, 2012 CFR

...mortgage must meet for the direct endorsement program are contained...must be originated through direct endorsement processing...requirements in accordance with the instructions contained in a handbook or...mortgagees approved for the direct endorsement procedure....

2012-04-01

218

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

219

THE THREE R'S OF DRAWING AND DESIGN COMPUTATION a drawing centered view of design process  

Microsoft Academic Search

A drawing centered view of design process focuses on the interplay between designer expertise, domain knowledge and media manipulation. We report on computational sketching software systems we have implemented to support recording, reasoning, and resolving in design.

MARK D GROSS; ELLEN YI-LUEN DO

220

Chromatin Diminution Process Regulates rRNA Gene Copy Number in Freshwater Copepods  

PubMed Central

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

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

2010-01-01

221

Human RNase H1 Is Associated with Protein P32 and Is Involved in Mitochondrial Pre-rRNA Processing  

PubMed Central

Mammalian RNase H1 has been implicated in mitochondrial DNA replication and RNA processing and is required for embryonic development. We identified the mitochondrial protein P32 that binds specifically to human RNase H1, but not human RNase H2. P32 binds human RNase H1 via the hybrid-binding domain of the enzyme at an approximately 1?1 ratio. P32 enhanced the cleavage activity of RNase H1 by reducing the affinity of the enzyme for the heteroduplex substrate and enhancing turnover, but had no effect on the cleavage pattern. RNase H1 and P32 were partially co-localized in mitochondria and reduction of P32 or RNase H1 levels resulted in accumulation of mitochondrial pre ribosomal RNA [12S/16S] in HeLa cells. P32 also co-immunoprecipitated with MRPP1, a mitochondrial RNase P protein required for mitochondrial pre-rRNA processing. The P32-RNase H1 complex was shown to physically interact with mitochondrial DNA and pre-rRNA. These results expand the potential roles for RNase H1 to include assuring proper transcription and processing of guanosine-cytosine rich pre-ribosomal RNA in mitochondria. Further, the results identify P32 as a member of the RNase H1 degradosome and the key P32 enhances the enzymatic efficiency of human RNase H1. PMID:23990920

Wu, Hongjiang; Sun, Hong; Liang, Xuehai; Lima, Walt F.; Crooke, Stanley T.

2013-01-01

222

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

223

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

224

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.

225

The Process of Implementation of Higher Education Reforms. R & D for Higher Education, 1979: 4.  

ERIC Educational Resources Information Center

The process of implementation of higher education reforms at nine universities and colleges in France, the Federal Republic of Germany, Italy, Poland, Sweden, Norway, and the United Kingdom is identified and compared; and a framework for implementation analysis is presented. After a brief review of the background for the study, the conceptual

Cerych, Ladislav

226

DETAILS OF POSTPASS PROCESSING OF TIME CORRECTION DATA Larry R. D'Addario  

E-print Network

. They are classified according to whether they are internal or external to the earth station, and according to what of the system can enter the process: (1) by affecting the initialization event, when the tape­time generating at other than the initialization event (``\\Deltat''); and (3) by causing errors in the time stamps

Groppi, Christopher

227

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, by varying or adapting those parts of the business process that are affected by them, whilst retaining. In Section 3, we use the taxonomy to evalu- ate the support of process flexibility in several contemporary

van der Aalst, Wil

228

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

229

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

SciTech Connect

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

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

2010-07-01

230

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

PubMed Central

The termini of rRNA processing intermediates and of mature rRNA species encoded by the 3' terminal region of 23S rDNA, by 4.5S rDNA, by the 5' terminal region of 5S rDNA and by the 23S/4.5S/5S intergenic regions from Zea mays chloroplast DNA were determined by using total RNA isolated from maize chloroplasts and 32P-labelled rDNA restriction fragments of these regions for nuclease S1 and primer extension mapping. Several processing sites detectable by both 3' and 5' terminally labelled probes could be identified and correlated to the secondary structure for the 23S/4.5S intergenic region. The complete 4.5S/5S intergenic region can be reverse transcribed and a common processing site for maturation of 4.5S and 5S rRNA close to the 3' end of 4.5S rRNA was detected. It is therefore concluded that 23S, 4.5S and 5S rRNA are cotranscribed. Images PMID:6093045

Strittmatter, G; Kssel, H

1984-01-01

231

Cormorants, Humans and the Symposium Process " I IIV principal rmnplain~ agairra~ h r Canadian Press 1995) to clain~sof the whole-  

E-print Network

releases and articles calling fi)r thc immrdiate halt of the "bird slaughter" at fish ponds and naturalEpilogue: Cormorants, Humans and the Symposium Process " I IIV principal rmnplain~ agairra~ h r Fat! tlul a birdcrnranroral rats fish sale desrrurtion of aquaculture develop- is o t w n c inr

Duffy, David Cameron

232

Mitochondrial Mismatch Analysis is Insensitive to the Mutational Process Alan R. Rogers, * Alexander E. Fraley, "f Michael J. Bamshad, t W. Scott Watkins, T and  

E-print Network

Mitochondrial Mismatch Analysis is Insensitive to the Mutational Process Alan R. Rogers, * Alexander E. Fraley, "f Michael J. Bamshad, t W. Scott Watkins, T and Lynn B. Jorde"f *Department, gamma distribution. Address for correspondence and reprints: Alan R. Rogers, De- partment

Rogers, Alan R.

233

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

234

A divergent Pumilio repeat protein family for pre-rRNA processing and mRNA localization.  

PubMed

Pumilio/feminization of XX and XO animals (fem)-3 mRNA-binding factor (PUF) proteins bind sequence specifically to mRNA targets using a single-stranded RNA-binding domain comprising eight Pumilio (PUM) repeats. PUM repeats have now been identified in proteins that function in pre-rRNA processing, including human Puf-A and yeast Puf6. This is a role not previously ascribed to PUF proteins. Here we present crystal structures of human Puf-A that reveal a class of nucleic acid-binding proteins with 11 PUM repeats arranged in an "L"-like shape. In contrast to classical PUF proteins, Puf-A forms sequence-independent interactions with DNA or RNA, mediated by conserved basic residues. We demonstrate that equivalent basic residues in yeast Puf6 are important for RNA binding, pre-rRNA processing, and mRNA localization. Thus, PUM repeats can be assembled into alternative folds that bind to structured nucleic acids in addition to forming canonical eight-repeat crescent-shaped RNA-binding domains found in classical PUF proteins. PMID:25512524

Qiu, Chen; McCann, Kathleen L; Wine, Robert N; Baserga, Susan J; Hall, Traci M Tanaka

2014-12-30

235

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

E-print Network

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 spectra are analysed using an automated line profile analysis method based on the Spectroscopy Made Easy codes of Valenti & Piskunov. Elemental abundances of moderate precision 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. Among the sample of 253 stars, we find 8 r-II stars and 35 r-I stars. 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. (*** abridged ***)

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

2005-07-04

236

Continuing Development of GOES-R SUVI Automated Solar Image Processing  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

237

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

NASA Astrophysics Data System (ADS)

Sardinera beach in Mona Island, Puerto Rico, has a great recreational and ecological value and is an important research place to gather information on shoreline processes in an area far from the main land and with only scarce man made influences. Beach rock exposures present along the shoreline in Sardinera Beach have increased considerably during the last decade. A new management plan is being developed for Mona Island and the Department of Natural Resources (DNRA) of Puerto Rico wants to better understand the beach sand dynamics on this and other Mona Island beaches. This research includes field and laboratory work that characterize coastal sedimentary processes and helps to better understand the shoreline changes as well as seasonal variations in sand movement and composition. This work also establish the logistics and methodology basis for further studies that will expand to other Mona Island beaches. Benchmarks, GPS coordinates, and landmarks were used to establish ten permanent beach profiles along Sardinera Beach. Beach profiles were (and will be) measured monthly. Sardinera Beach sands are composed mostly of carbonate (CaCO3) components, products of the combination of biological, chemical and diagenetic processes, high grade of micritization, and of lithic limestone fragments. Sand composition differences between Sardinera Beach, the Mona Shelf and adjacent beach, reef crest and reef lagoon systems suggest Sardinera sands are not replenished by the modern marine components produced in these environments. The input of "fresh bioclasts" in this beach seems to be limited by natural (beach rock) and mane made (dock) barriers along the shore and by alteration in the current patterns produced by the man made aperture of the reef. Sardinera's micritized and recrystalized sand deposits seem to have been re-transported between the reefal lagoon and the beach. Sand volume analysis indicates a total sand loss of 1,322 m3 between the months of September to April. Aerial images from the years 1977, 1992 and 2003 show 14 to 27 meters of recession along the coast line.

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

2008-12-01

238

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

239

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

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 (Behrens and Flagg, 1986). Phase II focused specifically on the shelf/slope frontal region of the mid-Atlantic bight off the Delmarva Peninsula. This project consisted of a series of ten cruises, a mooring array, and a series of over-flights by NASA aircraft. Hydrographic data were collected on eight of the cruises, six of which were primarily mooring deployment or recovery cruises. The cruises were consecutively designated SEEP2-01 to SEEP2-10. Two cruises (SEEP2-04 and SEEP2-07) were dedicated to investigating benthic processes and hydrographic data were not collected.

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

1989-12-01

240

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

NASA Astrophysics Data System (ADS)

A few rare halo giants in the range [Fe/H] ~= -2.9 0.3 exhibit r-process element abundances that vary as a group by factors up to [r/Fe] ~80, relative to those of the iron peak and below. Yet, the astrophysical production site of these r-process elements remains unclear. We report initial results from four years of monitoring the radial velocities of 17 r-process-enhanced metal-poor giants to detect and characterize binaries in this sample. We find three (possibly four) spectroscopic binaries with orbital periods and eccentricities that are indistinguishable from those of Population I binaries with giant primaries, and which exhibit no signs that the secondary components have passed through the asymptotic giant branch stage of evolution or exploded as supernovae. The other 14 stars in our sample appear to be singleincluding 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; Nordstrm, Birgitta; Buchhave, Lars A.; Beers, Timothy C.

2011-12-01

241

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

242

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 Mller

2014-06-10

243

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

244

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

245

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

SciTech Connect

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

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

1990-01-01

246

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

247

A High-entropy-wind r-process Study Based on Nuclear-structure Quantities from the New Finite-range Droplet Model Frdm(2012)  

NASA Astrophysics Data System (ADS)

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

Kratz, Karl-Ludwig; Farouqi, Khalil; Mller, Peter

2014-09-01

248

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

PubMed Central

We report the characterization of a novel factor, Rsa4p (Ycr072cp), which is essential for the synthesis of 60S ribosomal subunits. Rsa4p is a conserved WD-repeat protein that seems to localize in the nucleolus. In vivo depletion of Rsa4p results in a deficit of 60S ribosomal subunits and the appearance of half-mer polysomes. Northern hybridization and primer extension analyses of pre-rRNA and mature rRNAs show that depletion of Rsa4p leads to the accumulation of the 27S, 25.5S and 7S pre-rRNAs, resulting in a reduction of the mature 25S and 5.8S rRNAs. Pulsechase analyses of pre-rRNA processing reveal that, at least, this is due to a strong delay in the maturation of 27S pre-rRNA intermediates to mature 25S rRNA. Furthermore, depletion of Rsa4p inhibited the release of the pre-60S ribosomal particles from the nucleolus to the nucleoplasm, as judged by the predominantly nucleolar accumulation of the large subunit Rpl25-eGFP reporter construct. We propose that Rsa4p associates early with pre-60S ribosomal particles and provides a platform of interaction for correct processing of rRNA precursors and nucleolar release of 60S ribosomal subunits. PMID:16221974

de la Cruz, Jess; Sanz-Martnez, Eloisa; Remacha, Miguel

2005-01-01

249

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

E-print Network

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

N. Izutani; H. Umeda; N. Tominaga

2008-10-31

250

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

E-print Network

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

Peterson, Ruth C

2013-01-01

251

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

252

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

253

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

254

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

PubMed

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

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

2013-03-01

255

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

256

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

257

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

E-print Network

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

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

2011-12-21

258

A High-Resolution Transmission-Type (TT) Phaser Based on Reflection-Type (RT) Units for Radio Analog Signal Processing (R-ASP)  

E-print Network

A high Radio Analog Signal Processing (R-ASP) resolution transmission-type (TT) phaser based on reflection-type (RT) phaser units is introduced, theoretically studied and experimentally demonstrated. It is first shown that RT phasers inherently exhibit higher R-ASP resolution than their TT counterparts because their group delay swing is proportional to the reflection coefficient associated with a resonator coupling mechanism (admittance inverter), easy to maximize towards unity, rather than to a coupled-line coupling coefficient, typically restricted to values will inferior to unity, as in the RT case. Moreover, a detailed sensitivity analysis reveals that the proposed phaser is simultaneously features high R-ASP resolution and low sensitivity to fabrication tolerance, which makes it an ideal solution for R-ASP. The proposed phaser exhibits a 5 ns group delay swing over a fractional bandwidth of about 50% around 4 GHz.

Zou, Lianfeng

2014-01-01

259

Improved Laboratory Transition Probabilities for Er II and Application to the Erbium Abundances of the Sun and Five r-Process-rich, Metal-poor Stars  

NASA Astrophysics Data System (ADS)

Recent radiative lifetime measurements accurate to +/-5% (Stockett et al. 2007, J. Phys. B 40, 4529) using laser-induced fluorescence (LIF) on 7 even-parity and 63 odd-parity levels of Er II have been combined with new branching fractions measured using a Fourier transform spectrometer (FTS) to determine transition probabilities for 418 lines of Er II. This work moves Er II onto the growing list of rare-earth spectra with extensive and accurate modern transition probability measurements using LIF plus FTS data. This improved laboratory data set has been used to determine a new solar photospheric Er abundance, log?=0.96+/-0.03 (?=0.06 from 8 lines), a value in excellent agreement with the recommended meteoritic abundance, log?=0.95+/-0.03. Revised Er abundances have also been derived for the r-process-rich metal-poor giant stars CS 22892-052, BD +17 3248, HD 221170, HD 115444, and CS 31082-001. For these five stars the average Er/Eu abundance ratio, =0.42, is in very good agreement with the solar-system r-process ratio. This study has further strengthened the finding that r-process nucleosynthesis in the early Galaxy, which enriched these metal-poor stars, yielded a very similar pattern to the r-process, which enriched later stars including the Sun.

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

2008-09-01

260

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

E-print Network

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

Taylor, Gary

261

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

E-print Network

condition. The model is discretized by a finite element method which uses a mesh consisting of trianglesModelling the Glass Press-Blow Process S.M.A. Allaart-Bruin, B.J. van der Linden, and R.M.M. Mattheij TUE, CASA, Eindhoven, The Netherlands sbruin@win.tue.nl Summary. For the modelling of the glass

Eindhoven, Technische Universiteit

262

The effect of a combined HeNe and i.r. laser treatment on the regeneration of the lymphatic system during the process of wound healing  

Microsoft Academic Search

To study the effect of a combined HeNe and i.r. laser treatment on the regeneration of the lymphatic system during the process of wound healing, we compared the evolution of a surgical induced incision wound in two groups of mice.

P. C. Lievens

1991-01-01

263

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

E-print Network

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

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

2008-04-28

264

Barkowsky, T. (2001). Mental processing of geographic knowledge. In D. R. Montello (Ed.), Spatial Information Theory -Foundations of Geographic Information Science (pp. 371-386).  

E-print Network

Barkowsky, T. (2001). Mental processing of geographic knowledge. In D. R. Montello (Ed.), Spatial Information Theory - Foundations of Geographic Information Science (pp. 371-386). Berlin: Springer. Mental form a hierarchical structure of lean knowledge. An actual mental image representation is constructed

Bremen, Universität

265

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

E-print Network

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

Cowan, John

266

The Association between Genetic Polymorphism and the Processing Efficiency of miR-149 Affects the Prognosis of Patients with Head and Neck Squamous Cell Carcinoma  

PubMed Central

MicroRNAs (miRNAs) play important roles in modulating the neoplastic process of cancers including head and neck squamous cell carcinoma (HNSCC). A genetic polymorphism (rs2292832, C>T) has been recently identified in the precursor of miR-149; nevertheless its clinicopathological implications remain obscure. In this study, we showed that miR-149 is down-regulated in HNSCC compared to normal mucosa and this is associated with a poorer patient survival. In addition, HNSCC patients with the T/T genotype have more advanced tumors and a worse prognosis. Multivariate analysis indicated that patients carried the T/T genotype have a 2.81-fold (95% CI: 1.584.97) increased risk of nodal metastasis and 1.66-fold (95% CI: 1.052.60) increased risk of mortality compared to other groups. T/T genotype also predicted the worse prognosis of buccal mucosa carcinoma subset of HNSCC. In vitro analysis indicated that exogenous miR-149 expression reduces the migration of HNSCC cells. Moreover, HNSCC cell subclones carrying the pri-mir-149 sequence containing the T variant show a low processing efficacy when converting the pre-mir-149 to mature miR-149. These findings suggest that miR-149 suppresses tumor cell mobility, and that the pre-mir-149 polymorphism may affect the processing of miR-149, resulting in a change in the abundance of the mature form miRNA, which, in turn, modulates tumor progression and patient survival. PMID:23272122

Tu, Hsi-Feng; Liu, Chung-Ji; Chang, Che-Lun; Wang, Pei-Wen; Kao, Shou-Yen; Yang, Cheng-Chieh; Yu, En-Hao; Lin, Shu-Chun; Chang, Kuo-Wei

2012-01-01

267

Determination of effective rAAV-mediated gene transfer conditions to support chondrogenic differentiation processes in human primary bone marrow aspirates.  

PubMed

The genetic modification of freshly aspirated bone marrow may provide convenient tools to enhance the regenerative capacities of cartilage defects compared with the complex manipulation of isolated progenitor cells. In the present study, we examined the ability and safety of recombinant adeno-associated virus (rAAV) serotype 2 vectors to deliver various reporter gene sequences in primary human bone marrow aspirates over time without altering the chondrogenic processes in the samples. The results demonstrate that successful rAAV-mediated gene transfer and expression of the lacZ and red fluorescent protein marker genes were achieved in transduced aspirates at very high efficiencies (90-94%) and over extended periods of time (up to 125 days) upon treatment with hirudin, an alternative anticoagulant that does not prevent the adsorption of the rAAV-2 particles at the surface of their targets compared with heparin. Application of rAAV was safe, displaying neither cytotoxic nor detrimental effects on the cellular and proliferative activities or on the chondrogenic processes in the aspirates especially using an optimal dose of 0.5?mg?ml(-1) hirudin, and application of the potent SOX9 transcription factor even enhanced these processes while counteracting hypertrophic differentiation. The current findings demonstrate the clinical value of this class of vector to durably and safely modify bone marrow aspirates as a means to further develop convenient therapeutic approaches to improve the healing of cartilage defects. PMID:25338919

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

2015-01-01

268

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

269

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

270

Comparative MicroRNA Expression Profiles of Cynomolgus Monkeys, Rat, and Human Reveal that miR-182 Is Involved in T2D Pathogenic Processes  

PubMed Central

Type 2 diabetes (T2D) is a prevalent disease that happens around the world and usually happens with insulin resistance. MicroRNAs (miRNAs) represented important roles in the suppression of gene expression and were proven to be related to human diseases. In this study, we used cynomolgus monkey fed with normal and high fatty diet (HFD), respectively, to analyze the miRNA expression profile in whole blood by deep sequencing. Finally in total 24 miRNAs with differential expression were filtered. Among them, miR-182 related to the insulin resistance by modulating FOXO1 and PI3K/AKT cascade and had the greatest copy number in the whole blood. Decrease of miR-182 in T2D cynomolgus individuals is completely consistent with the previous studies in human and rat. Integrating miR-182 tissue expression profile, target genes, and copy number in blood reveals that miR-182 plays a key role in crucial genes modulation, such as FOXO1 and BHLHE22, which leads to potential hyperglycemia and modulates the insulin secretion. In addition, miR-182 might regulate the processes of both cell proliferation and apoptosis that play crucial role in determining the cells' fate. Therefore, miR-182 can be a biomarker in diagnosis of the potential T2D that has benefits for medical purpose.

Zhou, Jinghui; Meng, Yuhuan; Tian, Shuai; Liu, Mingyu; Zhuo, Min; Zhang, Yu; Wang, Xiaoning

2014-01-01

271

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

E-print Network

on kidney weight in white-tailed deer. Growth 44:46-53. Smith, M. H. and R. K. Chesser. 1981. Rationale-hemoglobin in white-tailed deer. Journal of Wildlife Management. 46:983-990. Smith, M. W., C. F. Aquadro, M. H. Smith rate in white-tailed deer. Evolution 37:282-291. Nei, M. and R. K. Chesser. 1983. Estimation

Chesser, Ronald Keith

272

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 (1815%) and Ni75-77 (102.8%, 143.6%, and 3024%, 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 (3011 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.; Mller, 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.; Whr, A.

2010-08-01

273

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

E-print Network

The {\\beta} decays of very neutron-rich nuclides in the Co-Zn region were studied experimentally at the National Superconducting Cyclotron Laboratory using the NSCL {\\beta}-counting station in conjunction with the neutron detector NERO. We measured the branchings for {\\beta}-delayed neutron emission (Pn values) for 74Co (18 +/- 15%) and 75-77Ni (10 +/- 2.8%, 14 +/- 3.6%, and 30 +/- 24%, respectively) for the first time, and remeasured the Pn values of 77-79Cu, 79,81Zn, and 82Ga. For 77-79Cu and for 81Zn 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 75Co (30 +/- 11 ms) and 80Cu (170+110 -50 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.

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

2010-11-23

274

Peripheral and/or central effects of racemic-, S(+)- and R(?)-flurbiprofen on inflammatory nociceptive processes: a c-Fos protein study in the rat spinal cord  

PubMed Central

We have evaluated the effects of intravenous or intraplantar racemic-, S(+)- and R(?)-flurbiprofen on both the carrageenan-evoked peripheral oedema and spinal c-Fos immunoreactivity, an indirect index of neurons involved in spinal nociceptive processes. Three hours after intraplantar injection of carrageenan (6?mg in 150??l of saline) in awake rats, a peripheral oedema and numerous c-Fos protein-like immunoreactive (c-Fos-LI) neurons in L4L5 segments were observed. c-Fos-LI neurons were essentially located in the superficial (III) and deep (VVI) laminae of the dorsal horn. Intravenous racemic-flurbiprofen (0.3, 3 and 9 ?mg?kg?1) dose-relatedly reduced the carrageenan-evoked oedema and spinal c-Fos expression (r=0.64, r=0.88 and r=0.84 for paw diameter, ankle diameter and number of c-Fos-LI neurons; P<0.05, P<0.001 and P<0.001 respectively). Similar effects to those of intravenous racemic-flurbiprofen were obtained with intravenous S(+)-flurbiprofen (0.3, 3 and 9?mg?kg?1) which dose-relatedly reduced the number of c-Fos-LI neurons (r=0.69, P<0.01) and diameters of paw and ankle (r=0.56 and r=0.52 respectively, P<0.05 for both). For the dose of 0.3?mg?kg?1 i.v., R(?)-flurbiprofen did not modify the number of c-Fos-LI neurons and produced a weak reduction of oedema at only the ankle level (2312% reduction, P<0.05). However, a ten times higher dose of R(?)-flurbiprofen (3?mg?kg?1 i.v.) was necessary to obtain effects comparable to those of S(+)- or racemic-flurbiprofen (0.3?mg?kg?1 i.v.). Intraplantar racemic-flurbiprofen (1, 10 and 30??g) dose-relatedly reduced the carrageenan-enhanced ankle diameter (r=0.81, P<0.001) and the number of c-Fos-LI neurons in L4L5 segments (r=0.83, P<0.001), with a 603% reduction of the number of c-Fos-LI neurons (P<0.001), and 303 and 677% reduction of paw and ankle diameter respectively (P<0.001 for both) for the dose of 30??g. For intraplantar S(+)-flurbiprofen (1, 10 and 30 ??g) the dose-related effects (r=0.77, r=0.60 and r=0.59 for c-Fos-LI neurons, paw and ankle diameters respectively, P<0.001, P<0.01 and P<0.01) were similar to those of racemic-flurbiprofen. In contrast, intraplantar R(?)-flurbiprofen (1, 10 and 30??g) did not have detectable effects on all studied parameters. The present study provides clear evidence for potent anti-inflammatory and antinociceptive effects of both intravenous or intraplantar racemic- and S(+)-flurbiprofen. These results further demonstrate marked anti-inflammatory and antinociceptive effects of intravenous, but not intraplantar, R(?)-flurbiprofen. These results suggest that the main site of action of racemic- and S(+)-flurbiprofen is in the periphery and indicate that the site of action of R(?)-flurbiprofen is mainly of central origin. PMID:9776348

Buritova, Jaroslava; Besson, Jean-Marie

1998-01-01

275

Frequency and Clinical Implication of the R450H Mutation in the Thyrotropin Receptor Gene in the Japanese Population Detected by Smart Amplification Process 2  

PubMed Central

In Japanese pediatric patients with thyrotropin (TSH) resistance, the R450H mutation in TSH receptor gene (TSHR) is occasionally observed. We studied the frequency and clinical implication of the R450H mutation in TSHR in the general population of Japanese adults using smart amplification process 2 (SmartAmp2). We designed SmartAmp2 primer sets to detect this mutation using a drop of whole blood. We analyzed thyroid function, antithyroid antibodies, and this mutation in 429 Japanese participants who had not been found to have thyroid disease. Two cases without antithyroid antibodies were heterozygous for the R450H mutation in TSHR. Thus, the prevalence of this mutation was 0.47% in the general population and 0.63% among those without antithyroid antibodies. Their serum TSH concentrations were higher than the average TSH concentration not only in subjects without antithyroid antibodies but also in those with antithyroid antibodies. The R450H mutation in TSHR is relatively common in the Japanese population and potentially affects thyroid function. The present study demonstrates that the SmartAmp2 method is useful to detect the R450H mutation in TSHR, which is one of the common causes of TSH resistance in the Japanese population. PMID:24895636

Yanagawa, Yoshimaro; Aoki, Tomoyuki; Morimura, Tadashi; Araki, Osamu; Kimura, Takao; Ogiwara, Takayuki; Kotajima, Nobuo; Yanagawa, Masumi; Murakami, Masami

2014-01-01

276

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

277

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

PubMed

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

Fang, Yan; Wu, Guozhen; Wang, Peijie

2012-03-01

278

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

E-print Network

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

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

2002-11-28

279

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...

280

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

NASA Astrophysics Data System (ADS)

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

Sivakumar, V.; Wyk, H. V.

281

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

NASA Astrophysics Data System (ADS)

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

Cescutti, G.; Chiappini, C.

2014-05-01

282

Takagi-Sugeno model based analysis of EWMA RtR control of batch processes with stochastic metrology delay and mixed products.  

PubMed

In many batch-based industrial manufacturing processes, feedback run-to-run control is used to improve production quality. However, measurements may be expensive and cannot always be performed online. Thus, the measurement delay always exists. The metrology delay will affect the stability and performance of the process. Moreover, since quality measurements are performed offline, delay is not fixed but is stochastic in nature. In this paper, a modeling approach Takagi-Sugeno (T-S) model is presented to handle stochastic metrology delay in both single-product and mixed-product processes. Based on the Markov characteristics of the delay, the membership of the T-S model is derived. Performance indices such as the mean and the variance of the closed-loop output of the exponentially weighted moving average (EWMA) control algorithm can be derived. A steady-state error of the process output always exists, which leads the output deviating from the target. To remove the steady-state error, an algorithm called compensatory EWMA run-to-run (COM-EWMA-RtR) algorithm is proposed. The validity of the T-S model analysis and the efficiency of the proposed COM-EWMA-RtR algorithm are confirmed by simulation. PMID:24235259

Zheng, Ying; Wong, David Shan-Hill; Wang, Yan-Wei; Fang, Huajing

2014-07-01

283

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

PubMed Central

In our previous study on individuals with autism spectrum disorder (ASD) (Sokhadze et al., Appl Psychophysiol Biofeedback 34:3751, 2009a) we reported abnormalities in the attention-orienting frontal event-related potentials (ERP) and the sustained-attention centro-parietal ERPs in a visual oddball experiment. These results suggest that individuals with autism over-process information needed for the successful differentiation of target and novel stimuli. In the present study we examine the effects of low-frequency, repetitive Transcranial Magnetic Stimulation (rTMS) on novelty processing as well as behavior and social functioning in 13 individuals with ASD. Our hypothesis was that low-frequency rTMS application to dorsolateral prefrontal cortex (DLFPC) would result in an alteration of the cortical excitatory/inhibitory balance through the activation of inhibitory GABAergic double bouquet interneurons. We expected to find post-TMS differences in amplitude and latency of early and late ERP components. The results of our current study validate the use of low-frequency rTMS as a modulatory tool that altered the disrupted ratio of cortical excitation to inhibition in autism. After rTMS the parieto-occipital P50 amplitude decreased to novel distracters but not to targets; also the amplitude and latency to targets increased for the frontal P50 while decreasing to non-target stimuli. Low-frequency rTMS minimized early cortical responses to irrelevant stimuli and increased responses to relevant stimuli. Improved selectivity in early cortical responses lead to better stimulus differentiation at later-stage responses as was made evident by our P3b and P3a component findings. These results indicate a significant change in early, middle-latency and late ERP components at the frontal, centro-parietal, and parieto-occipital regions of interest in response to target and distracter stimuli as a result of rTMS treatment. Overall, our preliminary results show that rTMS may prove to be an important research tool or treatment modality in addressing the stimulus hypersensitivity characteristic of autism spectrum disorders. PMID:19941058

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

2009-01-01

284

Production processes of third generation squarks in an R-parity breaking model at HERA and LEP2  

Microsoft Academic Search

We propose a possible scenario in the framework of the MSSM with R-parity breaking interactions of the scalar tops (stops) and the scalar bottoms (sbottoms) to interpret the anomalous events with the high Q2 recently observed at HERA. In our model, two stops are almost degenerate in mass and decay into (sbottom + W-boson) as well as (positron + d-quark).

Tadashi Kon; Tetsuro Kobayashi; Takashi Matsushita; Yoshimasa Kurihara

1998-01-01

285

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

SciTech Connect

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

Hosmer, P.; Estrade, A.; Montes, F.; Ouellette, M.; Pellegrini, E. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Schatz, H. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824 (United States); Aprahamian, A. [Department of Physics and Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Arndt, O.; Pfeiffer, B. [Institut fuer Kernchemie, Universitaet Mainz, Fritz-Strassmann Weg 2, D-55128 Mainz (Germany); HGF Virtuelles Institut fuer Kernstruktur und Nukleare Astrophysik (Germany); Clement, R. R. C.; Mueller, W. F.; Morton, A. C.; Pereira, J.; Santi, P.; Steiner, M.; Stolz, A. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Farouqi, K. [Department of Astronomy and Astrophysics and Joint Institute for Nuclear Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Kratz, K.-L. [HGF Virtuelles Institut fuer Kernstruktur und Nukleare Astrophysik (Germany); Max-Planck-Institut fuer Chemie (Otto-Hahn-Institut), J.-J.-Becherweg 27, D-55128 Mainz (Germany); Liddick, S. N.; Mantica, P. F. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Chemistry, Michigan State University, East Lansing, Michigan 48824 (United States)

2010-08-15

286

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

287

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...

288

The Mutual Exclusion Problem for Unreliable Processes: Preliminary Rt~port Ronald L. Rivest 'and Vaughan R. Pratt  

E-print Network

as a subroutine. and is not quite as. elegant as the two-process solution. Introduction I n thi~ introduction we first make precise the model of paraUel compul alion that we are using, and 'then specify carefully

Rivest, Ronald L.

289

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

290

Cross Section Measurement of 9Be(?,n)8Be and Implications for ?+?+n -> 9Be in the r-Process  

E-print Network

Models of the r-process are sensitive to the production rate of 9Be because, in explosive environments rich in neutrons, alpha(alpha n,gamma)9Be is the primary mechanism for bridging the stability gaps at A=5 and A=8. The alpha(alpha n,gamma)9Be reaction represents a two-step process, consisting of alpha+alpha -> 8Be followed by 8Be(n,gamma)9Be. We report here on a new absolute cross section measurement for the 9Be(gamma,n)8Be reaction conducted using a highly-efficient, 3He-based neutron detector and nearly-monoenergetic photon beams, covering energies from E_gamma = 1.5 MeV to 5.2 MeV, produced by the High Intensity gamma-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 alpha(alpha n,gamma)9Be reaction rate could have implications for the r-process in explosive environments such as Type II supernovae.

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

2011-12-07

291

{beta}-decay half-lives and {beta}-delayed neutron emission probabilities of nuclei in the region A < or approx. 110, relevant for the r process  

SciTech Connect

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

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

2009-03-15

292

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

293

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

294

Improvements of the sound perception processing of the anthropomorphic flutist robot (WF4R) to effectively interact with humans  

Microsoft Academic Search

The development of the anthropomorphic flutist robot, at Waseda University, has demonstrated how the robot can communicate with humans at emotional level by performing musical scores with expressiveness and by transferring basic skills from robot to beginners. However, the interaction among humans is characterized by a highly interactive process of analyzing and responding to incoming stimuli from the partner. Even

K. Suefuji; A. Takanishi

2005-01-01

295

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...

296

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

ERIC Educational Resources Information Center

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

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

2005-01-01

297

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...

298

12.1. R p R. p R (p) R.  

E-print Network

. 12. 12.1. R p R. p R (p) R. . (): a, b (p), p a p b, , p ab. ab (p). (): p = ab. (p) , a (p) b (p). a (p), b R ; ako b (p), a R . 12.2. R - . . , p = {0} R . x p\\{0}. pi R, i = 1, . . . , r, x = r i=1 pi. p

Kasparian, Azniv

299

Insertion, coupling and elimination processes in the reactions of the unsaturated alkyl-bridged complexes [Mo?(??-C?H?)?(?-CH?R)(?-PCy?)(CO)?] (R = H, Ph) with isocyanides and secondary phosphines.  

PubMed

The methyl-bridged complex [Mo2Cp2(?-Me)(?-PCy2)(CO)2] (Cp = ?(5)-C5H5) reacted with stoichiometric amounts of CN(t)Bu at 243 K to give the C,O:C,O-bridged acyl complex [Mo2Cp2{?-C,O:C,O-C(O)Me}(?-PCy2)(CN(t)Bu)(CO)], which at room temperature slowly rearranges into its iminoacyl-bridged isomer [Mo2Cp2(?-C,N:C,N-MeCN(t)Bu)(?-PCy2)(CO)2]. In contrast, the C:O-bridged acyl complex [Mo2Cp2{?-C:O-C(O)Me}(?-PCy2)(CN(t)Bu)(CO)] was the major product obtained when the above reaction was carried out at room temperature. Density Functional Theory (DFT) was used to find the most likely structures of all these isomers, of which the iminoacyl complex was the absolute minimum. In contrast to the above reactions, up to three molecules of the ligand added rapidly to the methyl complex when using the aryl isocyanides CNR (R = o-C6H4Me, p-C6H4OMe), triggering the coupling between the methyl ligand and one of the cyclopentadienyl groups to give the corresponding methylcyclopentadiene derivatives [Mo2Cp(?(4)-C5H5Me)(?-PCy2)(CNR)3(CO)]. Carbonylation of the latter complex (R = o-C6H4Me) induced the displacement of the ?(4)-bound ligand, but also gave small yields of the hydride derivative [Mo2Cp(?(5)-C5H4Me)(?-H)(?-PCy2){CN(o-C6H4Me)}(CO)3] (Mo-Mo = 3.2467(5) ), the latter resulting from a C-H cleavage in the methylcyclopentadiene ligand. The reaction of the title complexes with phosphines HPR (R' = Et, Ph) gave two major products: the corresponding aldehyde complexes [Mo2Cp2(?-PCy2)(?-PR){?(2)-C(O)HR}(CO)] (Mo-Mo = 2.8288(5) when R = CH2Ph and R' = Et) and the dicarbonyl complexes [Mo2Cp2(?-PCy2)(?-PR)(CO)2], these following from alternative reductive elimination processes, from hydrogen and either acyl or alkyl ligands, respectively. PMID:24699932

Alvarez, M Angeles; Garca, M Esther; Garca-Viv, Daniel; Martnez, M Eugenia; Ramos, Alberto; Ruiz, Miguel A

2014-06-01

300

Spectroscopic Studies of Extremely Metal-Poor Stars with the Subaru High Dispersion Spectrograph. II. The r-Process Elements, Including Thorium  

NASA Astrophysics Data System (ADS)

We have obtained high-resolution, high signal-to-noise near-UV-blue spectra of 22 very metal-poor stars ([Fe/H]<-2.5) with the Subaru High Dispersion Spectrograph and measured the abundances of elements from C to Th. The metallicity range of the observed stars is -3.2<[Fe/H]<-2.4. As found by previous studies, the star-to-star scatter in the measured abundances of neutron-capture elements in these stars is very large, much greater than could be assigned to observational errors, in comparison with the relatively small scatter in the ?- and iron-peak elements. In spite of the large scatter in the ratios of the neutron-capture elements relative to iron, the abundance patterns of heavy neutron-capture elements (56<=Z<~72) are quite similar within our sample stars. The Ba/Eu ratios in the 11 very metal-poor stars in our sample in which both elements have been detected are nearly equal to that of the solar system r-process component. Moreover, the abundance patterns of the heavy neutron-capture elements (56<=Z<=70) in seven objects with clear enhancements of the neutron-capture elements are similar to that of the solar system r-process component. These results prove that heavy neutron-capture elements in these objects are primarily synthesized by the r-process. In contrast, the abundance ratios of the light neutron-capture elements (38<=Z<=46) relative to the heavier ones (56<=Z<=70) exhibit a large dispersion. Our inspection of the correlation between Sr and Ba abundances in very metal-poor stars reveals that the dispersion of the Sr abundances clearly decreases with increasing Ba abundance. This trend is naturally explained by hypothesizing the existence of two processes, one that produces Sr without Ba and another that produces Sr and Ba in similar proportions. This result should provide a strong constraint on the origin of the light neutron-capture elements at low metallicity. We have identified a new highly r-process element enhanced, metal-poor star, CS 22183-031, a giant with [Fe/H]=-2.93 and [Eu/Fe]=+1.2. We also identified a new, moderately r-process-enhanced, metal-poor star, CS 30306-132, a giant with [Fe/H]=-2.42 and [Eu/Fe]=+0.85. The abundance ratio of the radioactive element Th (Z=90) relative to the stable rare-earth elements (e.g., Eu) in very metal-poor stars has been used as a cosmochronometer by a number of previous authors. Thorium is detected in seven stars in our sample, including four objects for which the detection of Th has already been reported. New detections of thorium have been made for the stars HD 6268, HD 110184, and CS 30306-132. The Th/Eu abundance ratios [log(Th/Eu)], are distributed over the range -0.10 to -0.59, with typical errors of 0.10 to 0.15 dex. In particular, the ratios in two stars, CS 31082-001 and CS 30306-132, are significantly higher than the ratio in the well-studied object CS 22892-052 and those of other moderately r-process-enhanced metal-poor stars previously reported. Since these very metal-poor stars are believed to be formed in the early Galaxy, this result suggests that the abundance ratios between Th and stable rare-earth elements such as Eu, both of which are presumably produced by r-process nucleosynthesis, may exhibit real star-to-star scatter, with implications for (1) the astrophysical sites of the r-process, and (2) the use of Th/Eu as a cosmochronometer. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

Honda, Satoshi; Aoki, Wako; Kajino, Toshitaka; Ando, Hiroyasu; Beers, Timothy C.; Izumiura, Hideyuki; Sadakane, Kozo; Takada-Hidai, Masahide

2004-05-01

301

The M(r) 43K major capsid protein of rice ragged stunt oryzavirus is a post-translationally processed product of a M(r) 67,348 polypeptide encoded by genome segment 8.  

PubMed

The nucleotide sequence of DNA complementary to rice ragged stunt oryzavirus (RRSV) genome segment 8 (S8) of an isolate from Thailand was determined. RRSVS8 is 1914 bp in size and contains a single large open reading frame (ORF) spanning nucleotides 23 to 1810 which is capable of encoding a protein of M(r) 67,348. The N-terminal amino acid sequence of a approximately 43K virion polypeptide matched to that inferred for an internal region of the S8 coding sequence. These data suggest that the 43K protein is encoded by S8 and is derived by a proteolytic cleavage. Predicted polypeptide sizes from this possible cleavage of S8 protein are 26K and 42K. Polyclonal antibodies raised against a maltose binding protein (MBP)-S8 fusion polypeptide (expressed in Escherichia coli) recognised four RRSV particle associated polypeptides of M(r) 67K, 46K, 43K and 26K and all except the 26K polypeptide were also highly immunoreactive to polyclonal antibodies raised against purified RRSV particles. Cleavage of the MBP-S8 fusion polypeptide with protease Factor X produced the expected 40K MBP and two polypeptides of apparent M(r) 46K and 26K. Antibodies to purified RRSV particles reacted strongly with the intact fusion protein and the 46K cleavage product but weakly to the 26K product. Furthermore, in vitro transcription and translation of the S8 coding region revealed a post-translational self cleavage of the 67K polypeptide to 46K and 26K products. These data indicate that S8 encodes a structural polypeptide, the majority of which is auto-catalytically cleaved to 26K and 46K proteins. The data also suggest that the 26K protein is the self cleaving protease and that the 46K product is further processed or undergoes stable conformational changes to a approximately 43K major capsid protein. PMID:8893791

Upadhyaya, N M; Zinkowsky, E; Kositratana, W; Waterhouse, P M

1996-01-01

302

Assessing the reliability and validity of the Revised Two Factor Study Process Questionnaire (R-SPQ2F) in Ghanaian medical students  

PubMed Central

Purpose: We investigated the validity and reliability of the Revised Two Factor Study Process Questionnaire (R-SPQ2F) in preclinical students in Ghana. Methods: The R-SPQ2F was administered to 189 preclinical students of the University for Development Studies, School of Medicine and Health Sciences. Both descriptive and inferential statistics with Cronbachs alpha test and factor analysis were done. Results: The mean age of the students was 22.69 0.18years, 60.8% (n=115) were males and 42.3% (n=80) were in their second year of medical training. The students had higher mean deep approach scores (31.237.19) than that of surface approach scores (22.626.48). Findings of the R-SPQ2F gave credence to a solution of two-factors indicating deep and surface approaches accounting for 49.80% and 33.57%, respectively, of the variance. The scales of deep approach (Cronbachs alpha, 0.80) and surface approach (Cronbachs alpha, 0.76) and their subscales demonstrated an internal consistency that was good. The factorial validity was comparable to other studies. Conclusion: Our study confirms the construct validity and internal consistency of the R-SPQ2F for measuring approaches to learning in Ghanaian preclinical students. Deep approach was the most dominant learning approach among the students. The questionnaire can be used to measure students approaches to learning in Ghana and in other African countries. PMID:25112447

2014-01-01

303

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...

304

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

305

Shelf Edge Exchange Processes, II: SEEP2-08, R/V ENDEAVOR cruise 188. 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 (Behrens and Flagg, 1986). Phase II focused specifically on the shelf/slope frontal region of the mid-Atlantic bight off the Delmarva Peninsula. This project consisted of a series of ten cruises, a mooring array, and a series of over-flights by NASA aircraft. Hydrographic data were collected on eight of the cruises, six of which were primarily mooring deployment or recovery cruises. The cruises were consecutively designated SEEP2-01 to SEEP2-10. Two cruises (SEEP2-04 and SEEP2-07) were dedicated to investigating benthic processes and hydrographic data were not collected.

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

1989-12-01

306

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

307

The RNA catabolic enzymes Rex4p, Rnt1p, and Dbr1p show genetic interaction with trans-acting factors involved in processing of ITS1 in Saccharomyces cerevisiae pre-rRNA.  

PubMed

Eukaryotes have two types of ribosomes containing either 5.8SL or 5.8SS rRNA that are produced by alternative pre-rRNA processing. The exact processing pathway for the minor 5.8SL rRNA species is poorly documented. We have previously shown that the trans-acting factor Rrp5p and the RNA exonuclease Rex4p genetically interact to influence the ratio between the two forms of 5.8S rRNA in the yeast Saccharomyces cerevisiae. Here we report a further analysis of ITS1 processing in various yeast mutants that reveals genetic interactions between, on the one hand, Rrp5p and RNase MRP, the endonuclease required for 5.8SS rRNA synthesis, and, on the other, Rex4p, the RNase III homolog Rnt1p, and the debranching enzyme Dbr1p. Yeast cells carrying a temperature-sensitive mutation in RNase MRP (rrp2-1) exhibit a pre-rRNA processing phenotype very similar to that of the previously studied rrp5-33 mutant: ITS2 processing precedes ITS1 processing, 5.8SL rRNA becomes the major species, and ITS1 is processed at the recently reported novel site A4 located midway between sites A2 and A3. As in the rrp5-Delta3 mutant, all of these phenotypical processing features disappear upon inactivation of the REX4 gene. Moreover, inactivation of the DBR1 gene in rrp2-1, or the RNT1 gene in rrp5-Delta3 mutant cells also negates the effects of the original mutation on pre-rRNA processing. These data link a total of three RNA catabolic enzymes, Rex4p, Rnt1p, and Dbr1p, to ITS1 processing and the relative production of 5.8SS and 5.8SL rRNA. A possible model for the indirect involvement of the three enzymes in yeast pre-rRNA processing is discussed. PMID:15525710

Faber, Alex W; Vos, Jan C; Vos, Harmjan R; Ghazal, Ghada; Elela, Sherif Abou; Rau, Hendrik A

2004-12-01

308

The RNA catabolic enzymes Rex4p, Rnt1p, and Dbr1p show genetic interaction with trans-acting factors involved in processing of ITS1 in Saccharomyces cerevisiae pre-rRNA  

PubMed Central

Eukaryotes have two types of ribosomes containing either 5.8SL or 5.8SS rRNA that are produced by alternative pre-rRNA processing. The exact processing pathway for the minor 5.8SL rRNA species is poorly documented. We have previously shown that the trans-acting factor Rrp5p and the RNA exonuclease Rex4p genetically interact to influence the ratio between the two forms of 5.8S rRNA in the yeast Saccharomyces cerevisiae. Here we report a further analysis of ITS1 processing in various yeast mutants that reveals genetic interactions between, on the one hand, Rrp5p and RNase MRP, the endonuclease required for 5.8SS rRNA synthesis, and, on the other, Rex4p, the RNase III homolog Rnt1p, and the debranching enzyme Dbr1p. Yeast cells carrying a temperature-sensitive mutation in RNase MRP (rrp2-1) exhibit a pre-rRNA processing phenotype very similar to that of the previously studied rrp5-33 mutant: ITS2 processing precedes ITS1 processing, 5.8SL rRNA becomes the major species, and ITS1 is processed at the recently reported novel site A4 located midway between sites A2 and A3. As in the rrp5-?3 mutant, all of these phenotypical processing features disappear upon inactivation of the REX4 gene. Moreover, inactivation of the DBR1 gene in rrp2-1, or the RNT1 gene in rrp5-?3 mutant cells also negates the effects of the original mutation on pre-rRNA processing. These data link a total of three RNA catabolic enzymes, Rex4p, Rnt1p, and Dbr1p, to ITS1 processing and the relative production of 5.8SS and 5.8SL rRNA. A possible model for the indirect involvement of the three enzymes in yeast pre-rRNA processing is discussed. PMID:15525710

FABER, ALEX W.; VOS, JAN C.; VOS, HARMJAN R.; GHAZAL, GHADA; ABOU ELELA, SHERIF; RAU, HENDRIK A.

2004-01-01

309

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

NASA Astrophysics Data System (ADS)

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

Hidaka, Hiroshi; Yoneda, Shigekazu

2011-07-01

310

PV Manufacturing R&D Project Status and Accomplishments under 'In-Line Diagnostics and Intelligent Processing' and 'Yield, Durability and Reliability': Preprint  

SciTech Connect

The PV Manufacturing R&D (PVMR&D) Project conducts cost-shared research and development programs with U.S. PV industry partners. There are currently two active industry partnership activities. ''In-line Diagnostics and Intelligent Processing'', launched in 2002, supports development of new in-line diagnostics and monitoring with real-time feedback for optimal process control and increased yield in the fabrication of PV modules, systems, and other system components. ''Yield, Durability and Reliability'', launched in late 2004, supports enhancement of PV module, system component, and complete system reliability in high-volume manufacturing. A second key undertaking of the PVMR&D Project is the collection and analysis of module production cost-capacity metrics for the U.S. PV industry. In the period from 1992 through 2005, the average module manufacturing cost in 2005 dollars fell 54% (5.7% annualized) to $2.74/Wp, and the capacity increased 18.6-fold (25% annualized) to 253 MW/yr. An experience curve analysis gives progress ratios of 87% and 81%, respectively, for U.S. silicon and thin-film module production.

Friedman, D. J.; Mitchell, R. L.; Keyes, B. M.; Bower, W. I.; King, R.; Mazer, J.

2006-05-01

311

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

PubMed Central

In radically resected gastric cancer the possibility to predict the site of relapse could be clinically relevant for the selection of post-surgical management. We previously showed that specific tumour integrins genotypes are independently associated with either peritoneal or hematogenous metastases (ITGA and ITGV). Recently VEGF and VEGF-R polymorphisms have been demonstrated to potentially affect tumour angiogenesis and the metastatic process in gastric cancer. We then investigated the role of VEGFs and VEGF-R genotyping in determining either peritoneal carcinosis or hematogenous metastases in radically resected gastric cancer patients. Tumour genotyping for integrins (ITGA and ITGV) was also performed according to our previous findings. Genotyping for VEGF-A, VEGF-C, VEGFR-1,2,3 and ITGA and ITGV was carried out on pT4a radically resected gastric tumours recurring with either peritoneal-only carcinosis or hematogenous metastases. 101 patients fulfilled the inclusion criteria: 57 with peritoneal carcinomatosis only and 44 with hematogenous spread only. At multivariate analysis, intestinal histology and the AC genotype of rs699947 (VEGFA) showed to independently correlate with hematogenous metastases (p?=?0.0008 and 0.008 respectively), whereas diffuse histology and the AA genotype of rs2269772 (ITGA) independently correlated with peritoneal-only diffusion (p?=?<0.0001 and 0.03 respectively). Our results seem to indicate that combining information from genotyping of rs699947 (VEGFA, AC), rs2269772 (ITGA, AA) and tumour histology could allow clinicians to individuate gastric cancer at high risk for recurrence either with peritoneal or hematogenous metastases. The selection tool deriving from this analysis may allow an optimal use of the available treatment strategies in these patients. PMID:22808003

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

2012-01-01

312

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

313

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

314

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

PubMed

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

Gonzlez, Asier; Casado, Carlos; Ario, Joaqun; Casamayor, Antonio

2013-01-01

315

Interpretation of Fracture Toughness and R-Curve Behavior by Direct Observation of Microfracture Process in Ti-Based Dendrite-Containing Amorphous Alloys  

NASA Astrophysics Data System (ADS)

Fracture properties of Ti-based amorphous alloys containing ductile ? dendrites were explained by directly observing microfracture processes. Three Ti-based amorphous alloys were fabricated by adding Ti, Zr, V, Ni, Al, and Be into a Ti-6Al-4V alloy by a vacuum arc melting method. The effective sizes of dendrites varied from 63 to 104 ?m, while their volume fractions were almost constant within the range from 74 to 76 pct. The observation of the microfracture of the alloy containing coarse dendrites revealed that a microcrack initiated at the amorphous matrix of the notch tip and propagated along the amorphous matrix. In the alloy containing fine dendrites, the crack propagation was frequently blocked by dendrites, and many deformation bands were formed near or in front of the propagating crack, thereby resulting in a zig-zag fracture path. Crack initiation toughness was almost the same at 35 to 36 MPa?m within error ranges in the three alloys because it was heavily affected by the stress applied to the specimen at the time of crack initiation at the crack tip as well as strength levels of the alloys. According to the R-curve behavior, however, the best overall fracture properties in the alloy containing fine dendrites were explained by mechanisms of blocking of the crack growth and crack blunting and deformation band formation at dendrites.

Jeon, Changwoo; Kim, Choongnyun Paul; Kim, Hyoung Seop; Lee, Sunghak

2015-01-01

316

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

PubMed Central

Arabidopsis miR319a/b/c primary transcripts are unusual due to the presence of a long stem and loop structure containing functional miR319a/b/c molecules. In our experiments carried out using high throughput sequencing (HTS), we have shown that additional microRNAs (miRNAs), miR319a.2/b.2/c.2 are generated from the upper part of the same hairpin structure. We have also found cognate miRNAa.2*/b.2*/c.2* to be present in the HTS results with a considerably lower number of reads. Northern hybridization revealed that miR319b.2 is mainly expressed in 35-day-old plant rosette leaves, as well as in stem and inflorescences of 42- and 53-day-old plants. Moreover, it carries multiple signatures of a functional miRNA, including as follows: (i) its biogenesis is HYL1-dependent; (ii) it is incorporated in a substantial amount into RISC complexes containing AGO1, AGO2, or AGO4 protein; (iii) 24 nt-long species of miR319b.2 have been found in inflorescences to be more abundant than 21 nt miR319b.2 species; (iv) it is present in various ratios to miR319b during plant development, which suggests the existence of a regulatory mechanism responsible for its biogenesis/processing; (v) there is an observed cross-species conservation of the miR319a/b/c stem nucleotide sequence extending beyond mature miRNA region; and (vi) all evidence suggests that intron-containing RAP2.12 mRNA isoform is the target for miR319b.2. All these features prompt us to claim miR319b.2 as a functional miRNA molecule. PMID:22639648

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

2012-01-01

317

WBSCR22/Merm1 is required for late nuclear pre-ribosomal RNA processing and mediates N7-methylation of G1639 in human 18S rRNA.  

PubMed

Ribosomal (r)RNAs are extensively modified during ribosome synthesis and their modification is required for the fidelity and efficiency of translation. Besides numerous small nucleolar RNA-guided 2'-O methylations and pseudouridinylations, a number of individual RNA methyltransferases are involved in rRNA modification. WBSCR22/Merm1, which is affected in Williams-Beuren syndrome and has been implicated in tumorigenesis and metastasis formation, was recently shown to be involved in ribosome synthesis, but its molecular functions have remained elusive. Here we show that depletion of WBSCR22 leads to nuclear accumulation of 3'-extended 18SE pre-rRNA intermediates resulting in impaired 18S rRNA maturation. We map the 3' ends of the 18SE pre-rRNA intermediates accumulating after depletion of WBSCR22 and in control cells using 3'-RACE and deep sequencing. Furthermore, we demonstrate that WBSCR22 is required for N(7)-methylation of G1639 in human 18S rRNA in vivo. Interestingly, the catalytic activity of WBSCR22 is not required for 18S pre-rRNA processing, suggesting that the key role of WBSCR22 in 40S subunit biogenesis is independent of its function as an RNA methyltransferase. PMID:25525153

Haag, Sara; Kretschmer, Jens; Bohnsack, Markus T

2015-02-01

318

R fluids  

E-print Network

A theory of collisionless fluids is developed in a unified picture, where nonrotating figures with anisotropic random velocity component distributions and rotating figures with isotropic random velocity component distributions, make adjoints configurations to the same system. R fluids are defined and mean and rms angular velocities and mean and rms tangential velocity components are expressed, by weighting on the moment of inertia and the mass, respectively. The definition of figure rotation is extended to R fluids. The generalized tensor virial equations are formulated for R fluids and further attention is devoted to axisymmetric configurations where, for selected coordinate axes, a variation in figure rotation has to be counterbalanced by a variation in anisotropy excess and vice versa. A microscopical analysis of systematic and random motions is performed under a few general hypotheses, by reversing the sign of tangential or axial velocity components of an assigned fraction of particles, leaving the distribution function and other parameters unchanged (Meza 2002). The application of the reversion process to tangential velocity components, implies the conversion of random motion rotation kinetic energy into systematic motion rotation kinetic energy. The application of the reversion process to axial velocity components, implies the conversion of random motion translation kinetic energy into systematic motion translation kinetic energy, and the loss related to a change of reference frame is expressed in terms of systematic (imaginary) motion rotation kinetic energy. A procedure is sketched for deriving the spin parameter distribution (including imaginary rotation) from a sample of observed or simulated large-scale collisionless fluids i.e. galaxies and galaxy clusters.

R. Caimmi

2007-10-20

319

Communicating Processes c! 2 || (c?. x:= c)  

E-print Network

) = Mw = 2 (w:= w+1) || (r:= r+1. x:= Mr­1 ) 2/64 #12;Communicating Processes c! 2 || (c?. x:= c) = Mw Processes c! 2 || (c?. x:= c) = Mw = 2 (w:= w+1) || (r:= r+1. x:= Mr­1 ) = Mw = 2 w = w+1 r = r+1 x = Mr:= w+1) || (r:= r+1. x:= Mr­1 ) = Mw = 2 w = w+1 r = r+1 x = Mr c! 1. (c! 2 || (c?. x:= c)). c

Hehner, Eric C.R.

320

Dominant role of the ERAP1 polymorphism R528K in shaping the HLA-B27 peptidome through differential processing determined by multiple peptide residues.  

PubMed

Objective. To characterize the alterations, and their mechanism, induced in the HLA-B27-bound peptidome expressed in live cells by the natural ERAP1 polymorphisms predisposing to ankylosing spondylitis: R528K and N575D/Q725R. Methods. HLA-B*27:05-bound peptides were isolated from 3 human lymphoid cell lines expressing distinct ERAP1 variants differing at residues 528 and/or 575/725. The HPLC-fractionated peptide pools were compared by mass spectrometry based on identity in molecular mass and chromatographic retention time. The relative amounts of each shared peptide in any given cell line pair were estimated from the respective ion peak intensities. Peptide sequencing was also carried out by mass spectrometry. Results. HLA-B27-bound ligands predominant in the context of the ERAP1 variant with K528 collectively showed higher molecular mass, higher frequency of N-terminal residues resistant to ERAP1 and bulkier residues downstream the N-terminus, relative to peptides predominant in the R528 context. None of these differences were observed with ERAP1 variants differing at positions 575/725, but not at residue 528. Neither R528K nor N575D/Q725R altered the mean length of B*27:05-bound ligands. Conclusion. The R528K, but not the N575D/Q725R polymorphism, alters the expression levels of many HLA-B*27:05-bound peptides, depending on the susceptibility of their N-terminal residues to trimming and the size of amino acid side chains at multiple positions downstream the N-terminus. The significant alterations in the B*27:05 peptidome and the structural features of the peptides that determine their differential expression in distinct ERAP1 contexts can explain the association of the R528K polymorphism with ankylosing spondylitis. This article is protected by copyright. All rights reserved. PMID:25469497

Sanz-Bravo, Alejandro; Campos, Jos; Mazariegos, Marina S; LpezdeCastro, Jos A

2014-12-01

321

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

SciTech Connect

The bond energies of a range of gem-diols, CH3R?C(OH)2 (R? = H, F, Cl, Br, CN, NO2, CF3, CH3CH2, CH3CH2CH2, CH3CH2CH2CH2, ((CH3)2)CH, (CH3)3C, ((CH3)2CH)CH2, (CH3CH2)(CH3)CH, C6H5 (CH3CH2)(CH3)CH) which serve as models for binding to a surface have been studied with density functional theory (DFT) and the molecular orbital G3(MP2) methods to provide thermodynamic data for the analysis of the photochemistry of ketones on TiO2. The ultraviolet (UV) photon-induced photodecomposition of adsorbed acetone and 3,3-dimethylbutanone on the rutile TiO2 (110) surface have been investigated with photon stimulated desorption (PSD) and temperature programmed desorption (TPD). The C-CH3 and C-C(R?) bond dissociation energies in CH3R?C(OH)2 were predicted, and our calculated bond dissociation energies are in excellent agreement with the available experimental values. We used a series of isodemic reactions to provide small corrections to the various bond dissociation energies. The calculated bond dissociation energies are in agreement with the observed photodissociation processes except for R? = CF3, suggesting that these processes are under thermodynamic control. For R? = CF3, reaction dynamics also play a role in determining the photodissociation mechanism. The gas phase Brnsted acidities of the gem-diols were calculated. For three molecules, R? = Cl, Br, and NO2, loss of a proton leads to the formation of a complex of acetic acid with the anion Cl-, Br-, and NO2-. The acidities of these three species are very high with the former two having acidities comparable to CF3SO3H. The ketones (R?RC(=O)) are weak Lewis acids except where addition of OH- leads to the dissociation of the complex to form an anion bonded to acetic acid, R' = NO2, Cl, and Br. The X-C bond dissociation energies for a number of X-CO2- species were calculated and these should be useful in correlating with photochemical reactivity studies.

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

2010-08-26

322

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...

323

Improved Laboratory Transition Probabilities for Ce II, Application to the Cerium Abundances of the Sun and Five r-process Rich, Metal-Poor Stars, and Rare Earth Lab Data  

E-print Network

Recent radiative lifetime measurements accurate to +/- 5% using laser-induced fluorescence (LIF) on 43 even-parity and 15 odd-parity levels of Ce II have been combined with new branching fractions measured using a Fourier transform spectrometer (FTS) to determine transition probabilities for 921 lines of Ce II. This improved laboratory data set has been used to determine a new solar photospheric Ce abundance, log epsilon = 1.61 +/- 0.01 (sigma = 0.06 from 45 lines), a value in excellent agreement with the recommended meteoritic abundance, log epsilon = 1.61 +/- 0.02. Revised Ce abundances have also been derived for the r-process-rich metal-poor giant stars BD+17 3248, CS 22892-052, CS 31082-001, HD 115444 and HD 221170. Between 26 and 40 lines were used for determining the Ce abundance in these five stars, yielding a small statistical uncertainty of 0.01 dex similar to the Solar result. The relative abundances in the metal-poor stars of Ce and Eu, a nearly pure r-process element in the Sun, matches r-process ...

Lawler, J E; Cowan, J J; Ivans, I I; Hartog, E A Den

2009-01-01

324

An R Package Conculsions/Future  

E-print Network

Motivation Methods An R Package Examples Conculsions/Future Methods and an R package for Bayesian inference with log-Gaussian Cox processes http://cran.r-project.org/web/packages/lgcp Benjamin M. Taylor Diggle) B. Taylor Log-Gaussian Cox Processes #12;Motivation Methods An R Package Examples Conculsions

Diggle, Peter J.

325

A P P LI CAT I O N F O R U N D E R G R A D UAT E A D M I S S I O N Use this application as a worksheet, then apply online at asu.edu/apply for faster processing.  

E-print Network

A P P LI CAT I O N F O R U N D E R G R A D UAT E A D M I S S I O N Use this application in your order of preference. First Choice Second Choice Major IF YOU ARE CHOOSING A MUSIC DEGREE, PLEASE INDICATE INSTRUMENT IF YOU ARE CHOOSING A MUSIC DEGREE, PLEASE INDICATE INSTRUMENT Degree College

Zhang, Junshan

326

A P P LI CAT I O N F O R U N D E R G R A D UAT E A D M I S S I O N Use this application as a worksheet, then apply online at asu.edu/apply for faster processing.  

E-print Network

A P P LI CAT I O N F O R U N D E R G R A D UAT E A D M I S S I O N Use this application Second Choice Major IF YOU ARE CHOOSING A MUSIC DEGREE, PLEASE INDICATE INSTRUMENT IF YOU ARE CHOOSING A MUSIC DEGREE, PLEASE INDICATE INSTRUMENT Degree College Professional Program Services (optional) If you

327

Process Efficiency Measurements in the Laser Engineered Net Shaping Process  

E-print Network

Process Efficiency Measurements in the Laser Engineered Net Shaping Process R.R. UNOCIC and J.N. DuPONT, Columbus, OH 43210. J.N. DuPONT, Associate Professor, is with the Materials Science and Engineering

DuPont, John N.

328

Two putative African swine fever virus helicases similar to yeast 'DEAH' pre-mRNA processing proteins and vaccinia virus ATPases D11L and D6R.  

PubMed

Two open reading frames (ORFs) of African swine fever virus (ASFV) encoding putative helicases have been sequenced. The two genes, termed D1133L and B962L, are located in the central region of the viral genome, but are separated by about 40 kb of DNA. Both genes are expressed late during ASFV infection of Vero cells, after replication of viral DNA has begun. Contiguous to D1133L, three other ORFs (D129L, D79L and D339L), encoding putative proteins of unknown function, have been sequenced. Proteins D1133L and B962L contain the amino acid motifs that characterize helicases of superfamily II. D1133L is most similar to a group of putative helicases which includes two proteins of vaccinia virus (D11L and D6R) involved in transcription of the viral genome, their homologues in other poxviruses, the protein encoded by ORF 4 of the yeast plasmids, pGKL2 and pSKL, and the previously identified ASFV protein, Q706L. B962L resembles a group of RNA-helicase-like proteins which includes three proteins of Saccharomyces cerevisiae involved in pre-mRNA splicing (PRP2, PRP16 and PRP22), Drosophila melanogaster KURZ and MLE, and vaccinia virus 18R. PMID:8262374

Yez, R J; Rodrguez, J M; Boursnell, M; Rodrguez, J F; Viuela, E

1993-12-01

329

Ordering process of Al 5Ti 3, hAl 2Ti and r-Al 2Ti with f.c.c.-based long-period superstructures in rapidly solidified Al-rich TiAl alloys  

Microsoft Academic Search

Change in microstructure and stability of superstructural phases in Al-rich TiAl alloys containing 58.062.5at.% Al were investigated using melt-spun ribbons. Ordering processes of long-period ordered phases such as Al5Ti3, h-Al2Ti and r-Al2Ti in the L10 matrix during annealing were examined. The presence of Al5Ti3 and h-Al2Ti phases in the L10 matrix was confirmed in melt-spun Ti60.0at.% Al and Ti62.5at.% Al

T. Nakano; A. Negishi; K. Hayashi; Y. Umakoshi

1999-01-01

330

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

331

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

EPA Science Inventory

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

332

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...

333

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.

334

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

. tardif, d. Carrer, p. CHaZette, m. ColomB, p. droBinski, e. dupont, J.-C. dupont, l. gomes, l. musson in the surface layer are known to be critical parameters throughout the fog life cycle as their chemical and chemical processes involved in continental fog. Early studies revealed that the development of radiation

Ribes, Aurélien

335

An Analysis of Apparent r-Mode Oscillations in Solar Activity, the Solar Diameter, the Solar Neutrino Flux, and Nuclear Decay Rates, with Implications Concerning the Solar Internal Structure and Rotation, and Neutrino Processes  

E-print Network

This article presents a comparative analysis of solar activity data, Mt Wilson diameter data, Super-Kamiokande solar neutrino data, and nuclear decay data acquired at the Lomonosov Moscow State University (LMSU). We propose that salient periodicities in all of these datasets may be attributed to r-mode oscillations. Periodicities in the solar activity data and in Super-Kamiokande solar neutrino data may be attributed to r-mode oscillations in the known tachocline, with normalized radius in the range 0.66 to 0.74, where the sidereal rotation rate is in the range 13.7 to 14.6 year-1. We propose that periodicities in the Mt Wilson and LMSU data may be attributed to similar r-mode oscillations where the sidereal rotation rate is approximately which we attribute to a hypothetical inner tachocline separating a slowly rotating core from the radiative zone. We also discuss the possible role of the RSFP (Resonant Spin Flavor Precession) process, which leads to estimates of the neutrino magnetic moment and of the magnetic field strength in or near the solar core.

P. A. Sturrock; L. Bertello; E. Fischbach; D. Javorsek II; J. H. Jenkins; A. Kosovichev; A. G. Parkhomov

2012-11-27

336

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

337

Prospects for Using High Neutron Fluxes in Igniting Capsules to Probe the Contributions of Excited Nuclear State Reactions to R, P, and S Process Nucleosynthesis  

NASA Astrophysics Data System (ADS)

The standard capsule design^1 for the National Ignition Facility offers the possibility of producing neutron fluxes that are high enough to explore a variety of multiple-step nuclear reactions that are relevant to astrophysical nucleosynthesis.^2 Calculations show that target nuclei seeded between the ablator and ice would see a neutron flux high enough to drive 10-20% into excited states via (n, n) reactions. Multiple-step reactions, including branches that pass through excited states with t > 1 ps can be studied using radiochemistry.^3 The 14 MeV neutrons due to the major D+T>? + n burn reaction drive the (n, n) excitations and (n, 2n) nuclear kinetics, while the ~ 2% minority D + D 3He + n, or T + p can drive (n,? ) or (p, ? ) reactions. Radiochemistry measurements of noble gas end species can be made with very high efficiency with only ~ 10^4 atoms required. Solid collection systems are being developed as well (with 10^7-8 atoms required at present). Spatially, temporally, and spectrally resolved x-ray emission as well neutron time-of-flight measurements offer the promise of constraining the distribution of doped nuclei and the temperature and therefore local rate of the thermonuclear burn. It should also be noted that the class of experiments proposed here involving short-lived intermediate states are complementary to those naturally studied at the proposed Rare Isotope Accelerator which is suited to probing reactions on states with much longer half lives. 1. Haan, S. W. et. al., Physics of Plasmas, 2 (6), 2480, part 2, 1995 2. Hoffman, R.D. et.al., Astrophysical Journal, 521 (2), 735, part 1, 1999. 3. Stoyer, M..A. et. al., in the 42nd Annual Meeting of the Division of Plasma Physics Meeting, Quebec City, Canada, October 23-27, 2000 *The work at LLNL was performed under the auspices of the U. S. Department of Energy by the University of California Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48.

Libby, Stephen; Tabak, Max; Hoffman, Robert; Stoyer, Mark; McNabb, Dennis; Ormand, Erich; Weiss, Morton; Mustafa, Mohammed; Ward, Richard

2001-10-01

338

Product Innovation, Process Innovation, and Size  

Microsoft Academic Search

We test the hypothesis that large firms devote a higher proportion of their research and development (R & D) expenditure on process innovation thansmaller firms. According to the estimates, process- and product R & D expenditure rise less than in proportion to size. The size effect is somewhat stronger for process R & D but the difference to product R

Michael Fritsch; Monika Meschede

2001-01-01

339

Curriculum Vitae Howard R. Turtle  

E-print Network

Curriculum Vitae Howard R. Turtle Center for Natural Language Processing Syracuse University · Xiaozhong Liu and Howard Turtle. Real-time User Interest for Real-time Ranking. Journal of the American, and Howard R. Turtle. PIC Matices: a Compu- tationally Tractable Class of Probabilistic Query Operators, ACM

Crowston, Kevin

340

Partial synthesis of (3R,6'R)-alpha-cryptoxanthin and (3R)-beta-cryptoxanthin from (3R,3'R,6'R)-lutein.  

PubMed

(3R,3'R,6'R)-Lutein (1), (3R,3'R)-zeaxanthin (2), (3R,6'R)-alpha-cryptoxanthin (3), and (3R)-beta-cryptoxanthin (4) are among dietary hydroxycarotenoids that have been identified in human serum, milk, and ocular tissues. While 1 containing 6% of 2 is commercially available, industrial production of optically active 3 and 4 has not yet been accomplished. Several processes have been developed that transform 1 into 3, 4, and minor quantities of (3R,5'RS,6'R)-3',4'-didehydro-5',6'-dihydro-beta,beta-caroten-3-ol (5) (a regioisomer of 3). In one process, lutein (1) was cleanly deoxygenated to 3 in the presence of trifluoroacetic acid (TFA) and Me3N.BH3 in CH2Cl2 at ambient temperature in nearly 90% yield. Reaction of lutein (1) with a Lewis acid (AlCl3, ZnBr2, ZnI2) and a hydride donor (Me3N.BH3, Na[BH3(OCOCF3)], NaCNBH3) in solvents such as CH2Cl2, THF, and TBME produced similar results. In a two-step process, high-temperature acid-catalyzed dehydration of 1 (propanol/water/acid, 90 degrees C) gave a mixture of anhydroluteins 6, 7, and 8 in 86% yield. In the second step, these dehydration products underwent ionic hydrogenation with TFA/Me3N.BH3 in CH2Cl2 to afford a mixture of 3 and 4 in nearly 80% yield that contained only 1% of 5. PMID:17266370

Khachik, Frederick; Chang, An-Ni; Gana, Audry; Mazzola, Eugene

2007-02-01

341

F I S C A L Y E A R 2 0 1 0 A N N U A L R E P O R T E N G I N E E R I N G T O M O R R O W ' S P O U L T R Y I N D U S T R Y  

E-print Network

audio and image signal processing, energy and water conservation, and food safety screening systems L T R Y I N D U S T R Y 2010 ANNUAL REPORT Agricultural Technology Research Program #12;A G R I C U R E V I E W For the Agricultural Technology Research Program (ATRP), fiscal year 2010 was a year

Bennett, Gisele

342

a r r i o r BUILDING# NAME LOCATION  

E-print Network

Admissions Parking Palmer Lake B l a c k W a r r i o r R i v e r BUILDING# NAME LOCATION 3430 1Hall 11-F D286 FergusonCenterParkingDeck 6-D 1022 FergusonStudentCenter 7-E 6085 FootballComplex 14-G 7059

Carver, Jeffrey C.

343

Fluctuation and Noise Letters Vol. 3, No. 1 (2003) R1R25  

E-print Network

as well as scaling behavior of crackling sound generated during the process of airway openings. We also rate; blood flow; airway opening; crackle sound; lung tissue. R1 #12;R2 B. Suki et al. 1. Introduction

Stanley, H. Eugene

344

Amy R. Krosch (updated May, 2012)  

E-print Network

processing of Black faces: Evidence from the N170 ERP. Paper Presentations Krosch, A. R., Berntsen, L., Jost at Four College Conference, Yale University, New Haven, CT. Krosch, A. R., Berntsen, L., Jost, J. TAmy R. Krosch (updated May, 2012) Psychology Department (646) 707.4565 New York University amy

345

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

NASA Astrophysics Data System (ADS)

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

Lee, Ho-Saeng; Son, Chang-Hyo

2010-05-01

346

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

Microsoft Academic Search

This report represents a technical assessment of the following advanced coal gasification processes: AVCO High Throughput Gasification (HTG) Process, Bell Single - Stage High Mass Flux (HMF) Process, Cities Service\\/Rockwell (CS\\/R) Hydrogasification Process, and the Exxon Catalytic Coal Gasification (CCG) Process. Each process is evaluated for its potential to produce SNG from a bituminous coal. In addition to identifying the

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

1981-01-01

347

Microcomputers in Process Control  

E-print Network

M1CROCOMPUTERS IN PROCESS CONTROL ", D. R. Vinson and N. Chatterjee (?)Air Products and Chemicals, Inc. Allentown, Pennsylvania Computers have been extensively used for process control and optimization since the 1970's. Many articles have.... Vinson and N. Chatterjee, "Computer Control of Unattended Plants," Sixth Annual Industrial Energy Conservation lechno10gy Conference, Houston, TX, April 1984. 2. S. L. Russek, T. M. Beckowski, and D. R. Vinson, "Computer Automated Start? up...

Vinson, D. R.; Chatterjee, N.

348

a r r i o r BUILDING# NAME LOCATION  

E-print Network

Palmer Lake B l a c k W a r r i o r R i v e r BUILDING# NAME LOCATION 3430 1North 3-I 5020 600 3421 EnvironmentalHealthandSafety 6-J 7054 FarrahHall 11-F D286 FergusonCenterParkingDeck 6-D 1022 FergusonStudentCenter 7-E 6085 FootballComplex 14-G 7059 FosterAuditorium 11-E 6118 Frank

Carver, Jeffrey C.

349

FINAL REPORT DETERMINATION OF THE PROCESSING RATE OF RPP WTP HLW SIMULANTS USING A DURAMELTER J 1000 VITRIFICATION SYSTEM VSL-00R2590-2 REV 0 8/21/00  

SciTech Connect

This report provides data, analysis, and conclusions from a series of tests that were conducted at the Vitreous State Laboratory of The Catholic University of America (VSL) to determine the melter processing rates that are achievable with RPP-WTP HLW simulants. The principal findings were presented earlier in a summary report (VSL-00R2S90-l) but the present report provides additional details. One of the most critical pieces of information in determining the required size of the RPP-WTP HLW melter is the specific glass production rate in terms of the mass of glass that can be produced per unit area of melt surface per unit time. The specific glass production rate together with the waste loading (essentially, the ratio of waste-in to glass-out, which is determined from glass formulation activities) determines the melt area that is needed to achieve a given waste processing rate with due allowance for system availability. As a consequence of the limited amount of relevant information, there exists, for good reasons, a significant disparity between design-base specific glass production rates for the RPP-WTP LAW and HLW conceptual designs (1.0 MT/m{sup 2}/d and 0.4 MT/m{sup 2}/d, respectively); furthermore, small-scale melter tests with HLW simulants that were conducted during Part A indicated typical processing rates with bubbling of around 2.0 MT/m{sup 2}/d. This range translates into more than a factor of five variation in the resultant surface area of the HLW melter, which is clearly not without significant consequence. It is clear that an undersized melter is undesirable in that it will not be able to support the required waste processing rates. It is less obvious that there are potential disadvantages associated with an oversized melter, over and above the increased capital costs. A melt surface that is consistently underutilized will have poor cold cap coverage, which will result in increased volatilization from the melt (which is generally undesirable) and increased plenum temperatures due to increased thermal radiation from the melt surface (which mayor may not be desirable but the flexibility to choose may be lost). Increased volatilization is an issue both in terms of the increased challenge to the off-gas system as well as for the ability to effectively close the recycle loops for volatile species that must be immobilized in the glass product, most notably technetium and cesium. For these reasons, improved information is needed on the specific glass production rates of RPP-WTP HLW streams in DuraMelterJ systems over a range of operating conditions. Unlike the RPP-WTP LAW program, for which a pilot melter system to provide large-scale throughout information is already in operation, there is no comparable HLW activity; the results of the present study are therefore especially important. This information will reduce project risk by reducing the uncertainty associated with the amount of conservatism that mayor may not be associated with the baseline RPP-WTP HLW melter sizing decision. After the submission of the first Test Plan for this work, the RPP-WTP requested revisions to include tests to determine the processing rates that are achievable without bubbling, which was driven by the potential advantages of omitting bubblers from the HLW melter design in terms of reduced maintenance. A further objective of this effort became the determination of whether the basis of design processing rate could be achieved without bubbling. Ideally, processing rate tests would be conducted on a full-scale RPP-WTP melter system with actual HLW materials, but that is clearly unrealistic during Part B1. As a practical compromise the processing rate determinations were made with HL W simulants on a DuraMelter J system at as close to full scale as possible and the DM 1000 system at VSL was selected for that purpose. That system has a melt surface area of 1.2 m{sup 2}, which corresponds to about one-third scale based on the specific glass processing rate of 0.4 MT/m{sup 2}/d assumed in the RPP-WTP HLW conceptual design, but would correspon

KRUGER AA; MATLACK KS; KOT WK; PEREZ-CARDENAS F; PEGG IL

2011-12-29

350

Affine configurations of 4 lines in R R R 3  

Microsoft Academic Search

We prove that affine configurations of 4 lines in R 3 are topologically and combina- torially homeomorphic to affine configurations of 6 points in R4. 1. Introduction. Consider four lines ? 1 ,? 2 ,? 3 ,? 4 in 3-dimensional space R 3 ; their affineconfiguration is their equivalence class under the natural (diagonal) action of the affine group Aff(3).

Jorge L. Arocha; Javier Bracho; Chaim Goodman-Strauss; Luis Montejano

351

Electrotechnologies in Process Industries  

E-print Network

IETe CONFERENCE ELECTROTECHNOLOGIES IN PROCESS INDUSTRIES K. R. AMARNATH Project Manager, Process Industries Electric Power Research Institute Palo Alto, California INTRODUCTION The Industrial Program at the Electric Power Research... and demonstrated by the Industrial Program. Process Industries such as chemicals, petroleum, paper, textiles, and food are vital to the American economy. These industries consume nearly half of all the manufacturing industry electricity usage. It is...

Amarnath, K. R.

352

Separation Process Economics  

E-print Network

.J., Separation processes ~ McGraw-Hill, New York, 1971. I (2) Heist, J.A. and T.S. Barron, "Fre~ze Separation Processes - Energy Efficien~y by Flexibility", 5th Annual IECTC, I Houston, TX, April 17, 1983. 31 ESL-IE-85-05-07 Proceedings from the Seventh... reduce h??t tran.r.r. At 11' g~ .ia. eo.t. 52'.41 per 1??? qaUon. ot .olv.nt IftStall.d 'roc.a. Squlpaent r_owed to build .nd o.-rat.. In.rgy r.quir...nt or 191 U'h per 11?? gallon?? Coat (fS aillioQ., 4019") ottered c_rcblly by at 1.aU thr?? tir...

Barron, T. S.; Wrobel, P. J.

353

A tutorial on optimization with graph cuts With applications in image and mesh processing and computer  

E-print Network

Q R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R RS

Wolf, Christian

354

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

355

Assessment of advanced coal gasification processes  

Microsoft Academic Search

A technical assessment of the following advanced coal gasification processes is presented: high throughput gasification (HTG) process single stage high mass flux (HMF) process (CS\\/R) hydrogasification process and the catalytic coal gasification (CCG) process. Each process is evaluated for its potential to produce synthetic natural gas from a bituminous coal. Key similarities, differences, strengths, weaknesses, and potential improvements to each

John McCarthy; Joseph Ferrall; Thomas Charng; John Houseman

1981-01-01

356

statistical computing in R 1 R in Sage  

E-print Network

statistical computing in R 1 R in Sage the language and environment R Monte Carlo integration making plots with R in Sage 2 Statistical Computing with R histograms of data fitting linear models 3 computing with R 1 R in Sage the language and environment R Monte Carlo integration making plots with R

Verschelde, Jan

357

Michael R. Hudec Publications  

E-print Network

Michael R. Hudec Publications November 3, 2011 Books, Manuals Hudec, M. R., and Jackson, M. P. A of Economic Geology poster + 10-p. booklet. Jackson, M. P. A., Schultz-Ela, D., Hudec, M. R., Watson, I. A/Geomechanics Symposium, San Francisco, June 26­29, 8 p., CD-ROM. Jackson, M. P. A., Hudec, M. R., and Dooley, T. P., 2010

Yang, Zong-Liang

358

R+?R2 loop quantum cosmology  

NASA Astrophysics Data System (ADS)

Working in Einstein frame, we introduce, in order to avoid singularities, holonomy corrections to the f(R)=R +?R2 model. We perform a detailed analytical and numerical study when holonomy corrections are taken into account in both Jordan and Einstein frames, obtaining, in Jordan frame, a dynamics which differs qualitatively, at early times, from the one of the original model. More precisely, when holonomy corrections are taken into account, the Universe is not singular, starting at early times in the contracting phase and bouncing to enter the expanding one where, as in the original model, it inflates. This dynamics is completely different from the one obtained in the original R +?R2 model, where the Universe is singular at early times and never bounces. Moreover, we show that these holonomy corrections may lead to better predictions for the inflationary phase as compared with current observations.

Amors, Jaume; de Haro, Jaume; Odintsov, Sergei D.

2014-05-01

359

R u t c o r R e p o r t  

E-print Network

for the linear complementarity problem. For this algorithm we prove global convergence under mild assumptions) is to determine x 2 R n ; w; v 2 R+ n ; satisfying f(x) = w \\Gamma v; (1a) w T (x \\Gamma `) = 0; (1b) v T (u \\Gamma x) = 0; (1c) ` Ÿ x Ÿ u; (1d) where `; u 2 ¯ R n = (R[ f\\Gamma1; +1g) n with ` i 6= u i ; 8i; and f

360

R u t c o r R e p o r t  

E-print Network

@rutcor.rutgers.edu #12; Rutcor Research Report RRR 43­94, December 1994 MULTIPLE CROSSINGS OF RELIABILITY FUNCTIONSR u t c o r Research R e p o r t RUTCOR ffl Rutgers Center for Operations Research ffl Rutgers­932­5472 Email: rrr@rutcor.rutgers.edu MULTIPLE CROSSINGS OF RELIABILITY FUNCTIONS Alexander K. Kelmans a RRR 43

361

Factor Analysis Using "R"  

ERIC Educational Resources Information Center

"R" (R Development Core Team, 2011) is a very powerful tool to analyze data, that is gaining in popularity due to its costs (its free) and flexibility (its open-source). This article gives a general introduction to using "R" (i.e., loading the program, using functions, importing data). Then, using data from Canivez, Konold, Collins, and Wilson

Beaujean, A. Alexander

2013-01-01

362

R U T C O R R E P O R T  

E-print Network

RESEARCH REPORT RRR 8-2001, JANUARY, 2001 CONTROL OF MARKET POWER IN ELECTRICITY AUCTIONS Michael HR U T C O R RESEARCH R E P O R T 587&25 5XWJHUV &HQWHU IRU 2SHUDWLRQV 5HVHDUFK 5XWJHUV 8QLYHUVLWUUU CONTROL OF MARKET POWER IN ELECTRICITY AUCTIONS Michael H. Rothkopf a RRR 8-2001, JANUARY, 2001 a RUTCOR

363

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

364

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

Chapter 11 Fundamental Plasma Processes in Saturn's Magnetosphere B.H. Mauk, D.C. Hamilton, T that control the extensive space environ- ment, or magnetosphere, of Saturn (see Chapter 9, for the global under- standing of the operations of Saturn's magnetosphere and its relationship to those of Earth

Johnson, Robert E.

365

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

366

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

367

77 FR 36907 - Establishment of Restricted Areas R-5402, R-5403A, R-5403B, R-5403C, R-5403D, R-5403E, and R...  

Federal Register 2010, 2011, 2012, 2013, 2014

...R-5403D, R-5403E, and R-5403F; Devils Lake, ND AGENCY: Federal Aviation Administration...restricted area airspace within the Devils Lake Military Operations Area (MOA), overlying...Grafton Range, in the vicinity of Devils Lake, ND. The new restricted areas...

2012-06-20

368

AphA and LuxR/HapR reciprocally control quorum sensing in vibrios  

PubMed Central

Bacteria cycle between periods when they perform individual behaviors and periods when they perform group behaviors. These transitions are controlled by a cellcell communication process called quorum sensing, in which extracellular signal molecules, called autoinducers (AIs), are released, accumulate, and are synchronously detected by a group of bacteria. AI detection results in community-wide changes in gene expression, enabling bacteria to collectively execute behaviors such as bioluminescence, biofilm formation, and virulence factor production. In this study, we show that the transcription factor AphA is a master regulator of quorum sensing that operates at low cell density (LCD) in Vibrio harveyi and Vibrio cholerae. In contrast, LuxR (V. harveyi)/HapR (V. cholerae) is the master regulator that operates at high cell density (HCD). At LCD, redundant small noncoding RNAs (sRNAs) activate production of AphA, and AphA and the sRNAs repress production of LuxR/HapR. Conversely, at HCD, LuxR/HapR represses aphA. This network architecture ensures maximal AphA production at LCD and maximal LuxR/HapR production at HCD. Microarray analyses reveal that 300 genes are regulated by AphA at LCD in V. harveyi, a subset of which is also controlled by LuxR. We propose that reciprocal gradients of AphA and LuxR/HapR establish the quorum-sensing LCD and HCD gene expression patterns, respectively. PMID:21325136

Rutherford, Steven T.; van Kessel, Julia C.; Shao, Yi; Bassler, Bonnie L.

2011-01-01

369

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

370

Hydrocarbon Processing`s gas processes `98  

SciTech Connect

The paper summarizes 82 processes for natural gas desulfurization, separation, liquefaction, and materials recovery, especially of hydrogen. Each entry describes the application, end products, the process, operating conditions, economics, installations, licensor, and gives references, if appropriate.

NONE

1998-04-01

371

CONTRIBUTED Solution-Processed Quantum  

E-print Network

CONTRIBUTED P A P E R Solution-Processed Quantum Dot Photodetectors Flexible thin-film-wavelength infrared. We also highlight the achievement of solution-processed photoconductive photo- detectors combining photoconductive gain and temporal responses faster than 30 ms, devices therefore compatible

372

Evolutionary Dynamics of Plant R-Genes  

NSDL National Science Digital Library

Plant R-genes involved in gene-for-gene interactions with pathogens are expected to undergo coevolutionary arms races in which plant specificity and pathogen virulence continually adapt in response to each other. Lending support to this idea, the solvent-exposed amino acid residues of leucine-rich repeats, a region of R-genes involved in recognizing pathogens, often evolve at unusually fast rates. But within-species polymorphism is also common in R-genes, implying that the adaptive substitution process is not simply one of successive selective sweeps. Here we document these features in available data and discuss them in light of the evolutionary dynamics they likely reflect.

Joy Bergelson (University of Chicago;Department of Ecology and Evolution); Martin Kreitman (University of Chicago;Department of Ecology and Evolution); Eli Stahl (University of Chicago;Department of Ecology and Evolution); Dacheng Tian (University of Chicago;Department of Ecology and Evolution)

2001-06-22

373

Analysis of the Transcriptional Regulator GlpR, Promoter Elements, and Posttranscriptional Processing Involved in Fructose-Induced Activation of the Phosphoenolpyruvate-Dependent Sugar Phosphotransferase System in Haloferax mediterranei  

PubMed Central

Among all known archaeal strains, the phosphoenolpyruvate-dependent phosphotransferase system (PTS) for fructose utilization is used primarily by haloarchaea, which thrive in hypersaline environments, whereas the molecular details of the regulation of the archaeal PTS under fructose induction remain unclear. In this study, we present a comprehensive examination of the regulatory mechanism of the fructose PTS in the haloarchaeon Haloferax mediterranei. With gene knockout and complementation, microarray analysis, and chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR), we revealed that GlpR is the indispensable activator, which specifically binds to the PTS promoter (PPTS) during fructose induction. Further promoter-scanning mutation indicated that three sites located upstream of the H. mediterranei PPTS, which are conserved in most haloarchaeal PPTSs, are involved in this induction. Interestingly, two PTS transcripts (named T8 and T17) with different lengths of 5? untranslated region (UTR) were observed, and promoter or 5? UTR swap experiments indicated that the shorter 5? UTR was most likely generated from the longer one. Notably, the translation efficiency of the transcript with this shorter 5? UTR was significantly higher and the ratio of T8 (with the shorter 5? UTR) to T17 increased during fructose induction, implying that a posttranscriptional mechanism is also involved in PTS activation. With these insights into the molecular regulation of the haloarchaeal PTS, we have proposed a working model for haloarchaea in response to environmental fructose. PMID:24334671

Cai, Lei; Cai, Shuangfeng; Zhao, Dahe; Wu, Jinhua; Wang, Lei; Liu, Xiaoqing; Li, Ming; Hou, Jing; Zhou, Jian; Liu, Jingfang; Han, Jing

2014-01-01

374

X = X1 . . . Xn Xi R I R V (I)  

E-print Network

. . . R R Spec R p Spec R V (p) Spec R p X X X X X X Y X Y X cod(Y, X) = cod(Y, X) cod(Y, X) (dim Xi -dim Y ) Xi X Y X p C[X] ht(p) = cod(V (p), X) R p Spec R V (p) Spec R R p0 p1 . . . pn p Spec R p) U X U Y = f C[U] (U, f) (U , f ) (V, g) V U U g = f|V = f |V r := dim OX,Y = cod(Y, X). X Y m

O'Grady, Kieran G.

375

Gas viscosities of azeotropic mixtures of the halogenated hydrocarbons R500, R502, and R503  

Microsoft Academic Search

Gas viscosities of azeotropic mixtures R500 (dichlorodifluoromethane (R12)-1, 1-difluoroethane (R152a)), R 502 (chlorodifluoromethane (R22)-chloropentafluoroethane (R115)), and R503 (chlorotrifluoromethane (R13)-trifluoromethane (R23)) were measured with an oscillating disk viscometer of the Maxwell type at 273.15-423.15 K up to 7.5 MPa. Two empirical equations for the viscosities were obtained; one is for the atmospheric viscosities as a function of temperature, and the other

Mitsuo Takahashi; Chiaki Yokoyama; Shinji Takahashi

1988-01-01

376

Dynamical R-Parity Violation  

NASA Astrophysics Data System (ADS)

We present a new paradigm for supersymmetric theories with R-parity violation (RPV). At high scale, R parity is conserved in the visible sector but spontaneously broken in the supersymmetry-breaking sector. The breaking is then dynamically mediated to the visible sector and is manifested via nonrenormalizable operators at low energy. Consequently, RPV operators originate from the Khler potential rather than the superpotential, and are naturally suppressed by the supersymmetry-breaking scale, explaining their small magnitudes. A new set of nonholomorphic RPV operators is identified and found to often dominate over the standard RPV ones. We study the relevant low-energy constraints arising from baryon-number violating processes, proton decay, and flavor changing neutral currents, which may all be satisfied if a solution to the standard model flavor puzzle is incorporated. The chiral structure of the RPV operators implies new and distinct collider signatures, indicating the need to alter current techniques in searching for RPV at the LHC.

Cski, Csaba; Kuflik, Eric; Volansky, Tomer

2014-04-01

377

75 FR 71532 - Airworthiness Directives; Robinson Helicopter Company (Robinson) Model R22, R22 Alpha, R22 Beta...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Helicopter Company (Robinson) Model R22, R22 Alpha, R22 Beta, and R22 Mariner Helicopters...directive (AD) for Robinson Model R22, R22 Alpha, R22 Beta, and R22 Mariner helicopters...to require for Robinson Model R22, R22 Alpha, R22 Beta, and R22 Mariner...

2010-11-24

378

75 FR 41104 - Airworthiness Directives; Robinson Helicopter Company (Robinson) Model R22, R22 Alpha, R22 Beta...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Helicopter Company (Robinson) Model R22, R22 Alpha, R22 Beta, and R22 Mariner Helicopters...directive (AD) for Robinson Model R22, R22 Alpha, R22 Beta, and R22 Mariner helicopters...adopting a new AD for Robinson Model R22, R22 Alpha, R22 Beta, and R22 Mariner...

2010-07-15

379

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, 2014

...R-3005A, R-3005B, R- 3005C, R-3005D and R-3005E at Fort Stewart, GA, to...The Rule This action amends Title 14 Code of Federal Regulations (14 CFR) part...the using agency for restricted areas R-3005A, R- 3005B, R-3005C,...

2010-03-24

380

[In Process Citation].  

PubMed

M. J. S. Belton, (*) J. W. Head III, A. P. Ingersoll, R. Greeley, A. S. McEwen, K. P. Klaasen, D. Senske, R. Pappalardo, G. Collins, A. R. Vasavada, R. Sullivan, D. Simonelli, P. Geissler, M. H. Carr, M. E. Davies, J. Veverka, P. J. Gierasch, D. Banfield, M. Bell, C. R. Chapman, C. Anger, R. Greenberg, G. Neukum, C. B. Pilcher, R. F. Beebe, J. A. Burns, F. Fanale, W. Ip, T. V. Johnson, D. Morrison, J. Moore, G. S. Orton, P. Thomas, R. A. West The first images of Jupiter, Io, Europa, and Ganymede from the Galileo spacecraft reveal new information about Jupiter's Great Red Spot (GRS) and the surfaces of the Galilean satellites. Features similar to clusters of thunderstorms were found in the GRS. Nearby wave structures suggest that the GRS may be a shallow atmospheric feature. Changes in surface color and plume distribution indicate differences in resurfacing processes near hot spots on Io. Patchy emissions were seen while Io was in eclipse by Jupiter. The outer margins of prominent linear markings (triple bands) on Europa are diffuse, suggesting that material has been vented from fractures. Numerous small circular craters indicate localized areas of relatively old surface. Pervasive brittle deformation of an ice layer appears to have formed grooves on Ganymede. Dark terrain unexpectedly shows distinctive albedo variations to the limit of resolution. M. J. S. Belton, National Optical Astronomy Observatories, 950 North Cherry Ave, Tucson, AZ 85719, USA. J. W. Head III, R. Pappalardo, G. Collins, Department of Geological Science, Brown University, Providence, RI 02912, USA. A. P. Ingersoll and A. R. Vasavada, Department of Geology and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA. R. Greeley and R. Sullivan, Department of Geology, Arizona State University, Tempe, AZ 85287-1414, USA. A. S. McEwen, P. Geissler, R. Greenberg, Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 87721, USA. K. P. Klaasen, D. Senske, T. V. Johnson, G. S. Orton, R. A. West, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA. D. Simonelli, J. Veverka, P. J. Gierasch, D. Banfield, M. Bell, J. A. Burns, P. Thomas, Department of Astronomy, Cornell University, Ithaca, NY 14853, USA. M. H. Carr, U.S. Geological Survey, Menlo Park, CA 94025, USA. M. E. Davies, RAND, Santa Monica, CA 90406, USA. C. R. Chapman, Southwest Research Institute, Boulder, CO 80302, USA. C. Anger, ITTRES Ltd, Calgary, Alberta TIY 5Z6, Canada. G. Neukum, Institute for Planetary Exploration, Deutsche Forschunganstalt fr Luft und Raumfahrt, Berlin, Germany. C. B. Pilcher, National Aeronautical and Space Administration, Washington, DC 20546, USA. R. F. Beebe, Department of Astronomy, New Mexico State University, Las Cruces, NM 88003, USA. F. Fanale, Institute for Geophysics, University of Hawaii, Honolulu, HI 96822, USA. W. Ip, Max Planck Institute fr Aeronomie, Lindau, Germany. D. Morrison and J. Moore, NASA Ames Research Center, Moffett Field, CA 94035, USA. (*) To whom correspondence should be addressed. E-mail: belton@noao.edu. PMID:17813508

1996-10-18

381

Proofs, Programs, Processes  

NASA Astrophysics Data System (ADS)

We study a realisability interpretation for inductive and coinductive definitions and discuss its application to program extraction from proofs. A speciality of this interpretation is that realisers are given by terms that correspond directly to programs in a lazy functional programming language such as Haskell. Programs extracted from proofs using coinduction can be understood as perpetual processes producing infinite streams of data. Typical applications of such processes are computations in exact real arithmetic. As an example we show how to extract a program computing the average of two real numbers w.r.t. to the binary signed digit representation.

Berger, Ulrich; Seisenberger, Monika

382

The R2R3-MYB Transcription Factor Gene Family in Maize  

PubMed Central

MYB proteins comprise a large family of plant transcription factors, members of which perform a variety of functions in plant biological processes. To date, no genome-wide characterization of this gene family has been conducted in maize (Zea mays). In the present study, we performed a comprehensive computational analysis, to yield a complete overview of the R2R3-MYB gene family in maize, including the phylogeny, expression patterns, and also its structural and functional characteristics. The MYB gene structure in maize and Arabidopsis were highly conserved, indicating that they were originally compact in size. Subgroup-specific conserved motifs outside the MYB domain may reflect functional conservation. The genome distribution strongly supports the hypothesis that segmental and tandem duplication contribute to the expansion of maize MYB genes. We also performed an updated and comprehensive classification of the R2R3-MYB gene families in maize and other plant species. The result revealed that the functions were conserved between maize MYB genes and their putative orthologs, demonstrating the origin and evolutionary diversification of plant MYB genes. Species-specific groups/subgroups may evolve or be lost during evolution, resulting in functional divergence. Expression profile study indicated that maize R2R3-MYB genes exhibit a variety of expression patterns, suggesting diverse functions. Furthermore, computational prediction potential targets of maize microRNAs (miRNAs) revealed that miR159, miR319, and miR160 may be implicated in regulating maize R2R3-MYB genes, suggesting roles of these miRNAs in post-transcriptional regulation and transcription networks. Our comparative analysis of R2R3-MYB genes in maize confirm and extend the sequence and functional characteristics of this gene family, and will facilitate future functional analysis of the MYB gene family in maize. PMID:22719841

Du, Hai; Feng, Bo-Run; Yang, Si-Si; Huang, Yu-Bi; Tang, Yi-Xiong

2012-01-01

383

ENGINEERING HOWARD R. HUGHES  

E-print Network

ENGINEERING College of HOWARD R. HUGHES HigHligHts At the Howard R. Hughes College of Engineering is an integral part of engineering studies, we also provide students with a superb technical education and strong of Energy Solar Decathlon 2013. Engineering and architecture students will design then build and operate

Hemmers, Oliver

384

Participants si n an Pr c r  

E-print Network

; as r s #12; arrati str ct r r r r #12; arrati c nt nt r r r #12; in r a a rati n str ct r #12; a rati n c nt nt #12; ca str ct r ca c nt nt #12; ct r a ia t p #12; r r ar #12; n r an a #12; #12; #12; r r r #12; #12; #12; t r t in rt an t c ni ac isiti n narrati s arrati p nt i appr ac s r c

Golbeck, Jennifer

385

Vision 96-Software and Systems Engineering Process Improvement, Montreal, December 1996. 1 Software and Systems Engineering Process  

E-print Network

Vision 96- Software and Systems Engineering Process Improvement, Montreal, December 1996. 1 Software and Systems Engineering Process Improvement at Oerlikon Aerospace Claude Y. Laporte, Nicola R software and systems engineering processes. The initiative started by performing a formal assessment

Laporte, Claude Y.

386

miR-192, miR-194, miR-215, miR-200c and miR-141 are downregulated and their common target ACVR2B is strongly expressed in renal childhood neoplasms.  

PubMed

Micro RNAs (miRNAs) play an important role during renal development and show a tissue-specific enrichment in the kidney. Nephroblastomas, embryonal renal neoplasms of childhood, are considered to develop from nephrogenic rests (NRs) and resemble morphologically and genetically developing kidney. We therefore investigated the role of kidney-enriched miRNAs in the pathogenesis of nephroblastomas. miR-192, miR-215 and miR-194 had a significantly lower expression in nephroblastomas regardless of the subtype compared with mature kidney measured by quantitative real-time-PCR. miR-141 and miR-200c showed a significantly lower expression in blastema-type and mixed-type tumors. In comparison with NRs, a significantly lower expression of miR-192, miR-194 and miR-215 was identified in blastema-type, mixed-type and stroma-type nephroblastomas and of miR-141 and miR-200c in blastema-type tumors. Kidney parenchyma had a significantly higher expression of miR-192, miR-194, miR-215 and miR-200c compared with NRs. In this study, the activin receptor type 2B (ACVR2B), a member of the transforming growth factor (TGF)-? pathway, was identified as single common target gene for miR-192, miR-215, miR-194, miR-141 and miR-200c in silico for the first time. The interaction between all five miRNAs and ACVR2B was also verified by an in vitro assay. Additionally, a distinct protein expression of ACVR2B was detected in 53 of 55 nephroblastomas paralleled by an upregulation of ACVR2B messenger RNA demonstrated in 25 nephroblastomas of all subtypes. A differential regulation of ACVR2B by miRNAs in NRs and nephroblastomas appears to be an important step in the pathogenesis of nephroblastomas implicating for the first time the TGF-? pathway in this process. PMID:22431721

Senanayake, Upeka; Das, Suman; Vesely, Paul; Alzoughbi, Wael; Frhlich, Leopold F; Chowdhury, Pooja; Leuschner, Ivo; Hoefler, Gerald; Guertl, Barbara

2012-05-01

387

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

388

Scientific Processes  

NSDL National Science Digital Library

In this interactive activity adapted from NOVA, expand your understanding of the scientific process. Watch two videos featuring animations and interviews with scientists, and notice how the processes unfold and vary from one investigation to the other.

Foundation, Wgbh E.

2007-08-01

389

Classical r-matrices via semidualisation  

NASA Astrophysics Data System (ADS)

We study the interplay between double cross sum decompositions of a given Lie algebra and classical r-matrices for its semidual. For a class of Lie algebras which can be obtained by a process of generalised complexification we derive an expression for classical r-matrices of the semidual Lie bialgebra in terms of the data which determines the decomposition of the original Lie algebra. Applied to the local isometry Lie algebras arising in three-dimensional gravity, decomposition, and semidualisation yields the main class of non-trivial r-matrices for the Euclidean and Poincar group in three dimensions. In addition, the construction links the r-matrices with the Bianchi classification of three-dimensional real Lie algebras.

Osei, Prince K.; Schroers, Bernd J.

2013-10-01

390

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

391

Hydrological analysis in R: Topmodel and beyond  

NASA Astrophysics Data System (ADS)

R is quickly gaining popularity in the hydrological sciences community. The wide range of statistical and mathematical functionality makes it an excellent tool for data analysis, modelling and uncertainty analysis. Topmodel was one of the first hydrological models being implemented as an R package and distributed through R's own distribution network CRAN. This facilitated pre- and postprocessing of data such as parameter sampling, calculation of prediction bounds, and advanced visualisation. However, apart from these basic functionalities, the package did not use many of the more advanced features of the R environment, especially from R's object oriented functionality. With R's increasing expansion in arenas such as high performance computing, big data analysis, and cloud services, we revisit the topmodel package, and use it as an example of how to build and deploy the next generation of hydrological models. R provides a convenient environment and attractive features to build and couple hydrological - and in extension other environmental - models, to develop flexible and effective data assimilation strategies, and to take the model beyond the individual computer by linking into cloud services for both data provision and computing. However, in order to maximise the benefit of these approaches, it will be necessary to adopt standards and ontologies for model interaction and information exchange. Some of those are currently being developed, such as the OGC web processing standards, while other will need to be developed.

Buytaert, W.; Reusser, D.

2011-12-01

392

Hydrocarbon Processing`s petrochemical processes `97  

SciTech Connect

The paper compiles information on numerous petrochemical processes, describing the application, the process, yields, economics, commercial plants, references, and licensor. Petrochemicals which are synthesized include: alkylbenzene, methylamines, ammonia, benzene, bisphenol-A, BTX aromatics, butadiene, butanediol, butyraldehyde, caprolactam, cumene, dimethyl terephthalate, ethanolamines, ethylbenzene, ethylene, ethylene glycols, ethylene oxide, formaldehyde, maleic anhydride, methanol, olefins, paraxylene, phenol, phthalic anhydride, polycaproamide, polyethylene, polyethylene terephthalate, polypropylene, PVC, styrene, terephthalic acid, urea, vinyl chloride, and xylene isomers.

NONE

1997-03-01

393

Raster data analysis with R  

NASA Astrophysics Data System (ADS)

The R system supports cutting-edge and reproducible data analysis across scientific disciplines. Its wide adoption is likely because the program is free and open-source, easy to use (relative to other programming languages), and because of the ease of extending it through packages (plug-ins). Packages for data analysis from most fields of research have been developed, often by domain specialists. R has strong support for spatial (geographic) data analysis but, until recently, support for raster data was somewhat limited. Raster data divides a region into rectangles ('cells' or 'pixels') and stores one or more values for each of these rectangles. This data type is frequently used in environmental research. The aim of the 'raster' package is to provide a basis for raster data analysis in R; and it is being used in agriculture, ecology, climatology, energy, landscape genetics, and other fields of research. Highlights of the 'raster' package include an easy to use raster algebra implementation and the availability a large set of functions for raster specific (e.g., focal and zonal), and spatial data specific (e.g. coordinate system transformations, spatial queries) computations. The package has the ability to deal with raster data sets of any size, but processing large data files is sometimes slow. Future work should improve this situation, but in many cases the ease of writing and maintaining scripts, and the ability to seamlessly integrate spatial and other types of data and methods, will outweigh the reduction in processing speed relative to what might be obtained by developing programs in, for example, C or Python.

Hijmans, R. J.

2011-12-01

394

MODELING OF ALUMINUM NANOPARTICLE FORMATION R. Schefflan  

E-print Network

MODELING OF ALUMINUM NANOPARTICLE FORMATION R. Schefflan D. Kalyon S. Kovenklioglu Stevens Picatinny Arsenal's process for making alumina coated nanoparticles of aluminum involves the conversion of gaseous aluminum, in the presence of helium carrier gas, to solid nanoparticles and their subsequent

395

Cosmic R-string in thermal history  

E-print Network

We study stabilization of an unstable cosmic string associated with spontaneously broken $U(1)_R$ symmetry, which otherwise causes a dangerous roll-over process. We demonstrate that in a gauge mediation model, messengers can receive enough corrections from the thermal plasma of the supersymmetric standard model particles to stabilize the unstable modes of the string.

Kohei Kamada; Tatsuo Kobayashi; Keisuke Ohashi; Yutaka Ookouchi

2013-03-12

396

Steven R. Dunbar Department of Mathematics  

E-print Network

Theory and Stochastic Processes Steven R. Dunbar Local Limit Theorems Rating Mathematicians Only of the Local Limit Theorem. Vocabulary 1. A local limit theorem describes how the probability mass function #12;Mathematical Ideas Introduction A local limit theorem describes how the probability mass function

Dunbar, Steve

397

David R. Black Gabrielle G. Long  

E-print Network

NIST Recommended Practice Guide Special Publication 960-10 X-Ray Topography David R. Black of crystals for technological applications and for many areas of crystal and thin-film growth and processing on most of the examples shown in this Practice Guide. X-ray topography would not have been possible at NBS/NIST

398

Updated 1-13 David R. Clifton  

E-print Network

Program and the Marine Corps Activity Based Cost Management System. He received the 2004 InternationalUpdated 1-13 David R. Clifton Deputy Assistant Deputy Commandant Installations and Logistics, Installation Reform Division, HQMC and led efforts to improve performance, process, and cost management at 22

399

PRINT ONLY: MARS Capitan R. D.  

E-print Network

PRINT ONLY: MARS Capitan R. D. Three Phases of Landscape Evolution in Gorgonum and Atlantis Basins, Mars [#1318] Three periods of landscape evolution are identified in Gorgonum and Atlantis basins, Mars. Volcanism, tectonic processes and climate change are the main controlling mechanisms which differentiated

Rathbun, Julie A.

400

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

401

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

402

AMP-Activated Kinase Regulates Cytoplasmic HuR  

Microsoft Academic Search

While transport of RNA-binding protein HuR from nucleus to cytoplasm is emerging as a key regulatory step for HuR function, the mechanisms underlying this process remain poorly understood. Here, we report that the AMP-activated kinase (AMPK), an enzyme involved in responding to metabolic stresses, potently regulates the levels of cytoplasmic HuR. Inhibition of AMPK, accomplished either through cell treatment or

Wengong Wang; Jinshui Fan; Xiaoling Yang; S. Furer-Galban; Isabel Lopez de Silanes; Cayetano von Kobbe; Jia Guo; Steve N. Georas; Fabienne Foufelle; D. Grahame Hardie; David Carling; Myriam Gorospe

2002-01-01

403

Gas viscosities of azeotropic mixtures of the halogenated hydrocarbons R500, R502, and R503  

SciTech Connect

Gas viscosities of azeotropic mixtures R500 (dichlorodifluoromethane (R12)-1, 1-difluoroethane (R152a)), R 502 (chlorodifluoromethane (R22)-chloropentafluoroethane (R115)), and R503 (chlorotrifluoromethane (R13)-trifluoromethane (R23)) were measured with an oscillating disk viscometer of the Maxwell type at 273.15-423.15 K up to 7.5 MPa. Two empirical equations for the viscosities were obtained; one is for the atmospheric viscosities as a function of temperature, and the other is for the viscosities in the whole range of the present measurement as a function of temperature and density.

Takahashi, M.; Yokoyama, C.; Takahashi, S.

1988-07-01

404

DEMONSTRATION BULLETIN: BIOLOGICAL DENITRIFICATION PROCESS, ECOMAT, INC.  

EPA Science Inventory

EcoMat, Inc. of Hayward, CA has developed a two-stage ex situ anoxic biofilter biodenitrification process. The process is a fixed film bioremediation, using biocarriers and specific bacteria to treat nitrate-contaminated water. Unique to EcoMat's process is a patented mixed bed r...

405

Signal Processing: Modal Analysis Experimental Modal Analysis  

E-print Network

Signal Processing: Modal Analysis Experimental Modal Analysis Conduct test excitation A j H = +- = +- = = 22222 1 2 #12;Signal Processing: Modal Analysis kririkr rrr ikv rrrr krir N r ik A j A j H = +- = +- = = 22222 1 2 #12;Signal Processing: Modal Analysis SDOF - Peak method Hik = ]/2

Rimon, Elon

406

Bacterial Production Lab State variables and processes  

E-print Network

B: Bacterial Growth Rate (gC h-1) Why do we want to measure processes? Objective: Measure bacterial growth rateBacterial Production Lab State variables and processes BDOM Other compounds (e.g., EtOH) CO2 r Var. Process #12;Growth Equation td Where: td Doubling time of population. x(t) Number or mass

Vallino, Joseph J.

407

MULTILATERAL INVERSION OF A r , C r AND D r BASIC HYPERGEOMETRIC SERIES  

E-print Network

MULTILATERAL INVERSION OF A r , C r AND D r BASIC HYPERGEOMETRIC SERIES MICHAEL J. SCHLOSSER multidimensional matrix inverses with A r and D r extensions of Jackson's 8 # 7 summation theorem three balanced MICHAEL J. SCHLOSSER This result was directly extracted from an instance of Bailey's [3, Eq. (4.7)] very

Schlosser, Michael

408

Muenke Syndrome Mutation, FgfR3P244R, Causes TMJ Defects  

PubMed Central

Muenke syndrome is characterized by various craniofacial deformities and is caused by an autosomal-dominant activating mutation in fibroblast growth factor receptor 3 (FGFR3P250R). Here, using mice carrying a corresponding mutation (FgfR3P244R), we determined whether the mutation affects temporomandibular joint (TMJ) development and growth. In situ hybridization showed that FgfR3 was expressed in condylar chondroprogenitors and maturing chondrocytes that also expressed the Indian hedgehog (Ihh) receptor and transcriptional target Patched 1(Ptch1). In FgfR3P244R mutants, the condyles displayed reduced levels of Ihh expression, H4C-positive proliferating chondroprogenitors, and collagen type II- and type X-expressing chondrocytes. Primary bone spongiosa formation was also disturbed and was accompanied by increased osteoclastic activity and reduced trabecular bone formation. Treatment of wild-type condylar explants with recombinant FGF2/FGF9 decreased Ptch1 and PTHrP expression in superficial/polymorphic layers and proliferation in chondroprogenitors. We also observed early degenerative changes of condylar articular cartilage, abnormal development of the articular eminence/glenoid fossa in the TMJ, and fusion of the articular disc. Analysis of our data indicates that the activating FgfR3P244R mutation disturbs TMJ developmental processes, likely by reducing hedgehog signaling and endochondral ossification. We suggest that a balance between FGF and hedgehog signaling pathways is critical for the integrity of TMJ development and for the maintenance of cellular organization. PMID:22622662

Yasuda, T.; Nah, H.D.; Laurita, J.; Kinumatsu, T.; Shibukawa, Y.; Shibutani, T.; Minugh-Purvis, N.; Pacifici, M.; Koyama, E.

2012-01-01

409

Process Control  

NSDL National Science Digital Library

This is a webpage with many learning objects concerning Process Control with lessons in Temperature, Level, Pressure, Flow, Analytical, Symbols, Tuning & Calibration, PID Controls and other basic concepts.

2012-10-22

410

Ris9-R-609(EN) Simulation ofa PWR Power Plant  

E-print Network

Ris9-R-609(EN) Simulation ofa PWR Power Plant for Process Control and Diagnosis Finn Ravnsbjerg Nielsen Risø National Laboratory, Roskilde, Denmark December 1991 #12;Simulation of a PWR Power Plant *^R, Denmark December 1991 #12;Abstract. A computer model of a simplified pressurized nuclear power plant

411

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

412

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

413

EASY Documentation Series CCFE-R (10) 02 The European  

E-print Network

EASY Documentation Series CCFE-R (10) 02 The European Activation File: EAF-2010 decay data library .............................................................................................. 2 Library processing section libraries, but the description and documentation of these libraries remained sparse, as most

414

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

415

Peat Processing  

NASA Technical Reports Server (NTRS)

Humics, Inc. already had patented their process for separating wet peat into components and processing it when they consulted NERAC regarding possible applications. The NERAC search revealed numerous uses for humic acid extracted from peat. The product improves seed germination, stimulates root development, and improves crop yields. There are also potential applications in sewage disposal and horticultural peat, etc.

1986-01-01

416

Solidification processing  

NASA Technical Reports Server (NTRS)

The solidification processing activities are reported. The following topics are studied: behavior of semisolid metals, purification and strengthening by fractional melting, continuous casting, control of ingot surface quality, and metal matrix composites. Formation of deoxidation products in steels is also investigated. Rapid solidification, crystal growth, experimental and mathematical modeling of solidification processes are explored.

1982-01-01

417

DEMONSTRATION BULLETIN: EX-SITU ANAEROBIC BIOREMEDIATION TECHNOLOGY - TNT - J.R. SIMPLOT COMPANY  

EPA Science Inventory

The J. R. Simplot Ex-Situ Anaerobic Bioremediation System, also known as the J.R. Simplot Anaerobic Biological Remediaton Process (the SABRE? Process), is a technology designed to destroy nitroaromatic and energetic compounds. The process does not evolve any known toxic intermedi...

418

Fluid catalytic cracking catalyst residue (FC3R)  

Microsoft Academic Search

A new industrial by-product obtained from the fluid catalytic cracking (FCC) process in petrol refinery is studied for construction uses. This by-product, named as fluid catalytic cracking catalyst residue (FC3R), is composed of original spherically shape particles and fragments produced in the catalytic process (300.1 ?m) that present highly irregular morphologies. FC3R presented a very high specific surface area that

J Pay; J Monz; M. V Borrachero

1999-01-01

419

Fusion process  

Microsoft Academic Search

In energy technology priority discussions, fusion takes varying positions in different countries. In the U.S., the fashion for solar power presently puts nuclear breeders in the shade, but that priority may reverse later; coal is an extended intermediate. In Europe, oil is the intermediate and nuclear is for the long term. Yet all the U.S., Europe, Japan, the U.S.S.R. want

Rose

1978-01-01

420

76 FR 72869 - Proposed Establishment of Restricted Areas R-5402, R-5403A, R-5403B, R-5403C, R-5403D, R-5403E...  

Federal Register 2010, 2011, 2012, 2013, 2014

...R-5403D, R-5403E, and R-5403F; Devils Lake, ND AGENCY: Federal Aviation Administration...restricted area airspace within the Devils Lake Military Operations Area (MOA), overlying...Grafton Range, in the vicinity of Devils Lake, ND. The new restricted areas would...

2011-11-28

421

Neutrinos, Weak Interactions, and r-process Nucleosynthesis  

E-print Network

Two of the key issues in understanding the neutron-to-proton ratio in a core-collapse supernova are discussed. One of these is the behavior of the neutrino-nucleon cross sections as supernova energies. The other issue is the many-body properties of the neutrino gas near the core when both one- and two-body interaction terms are included.

A. B. Balantekin

2006-08-18

422

The Design Process for "PLATO[R] Math Problem Solving."  

ERIC Educational Resources Information Center

PLATO Learning, Inc., a developer of computer-based instruction, recently released "Math Problem Solving." This product was designed to teach strategies for solving math problems, and consists of 19 problem-solving activities, ranging from basic math to algebra. Each activity includes tools to help find a solution and rule-based coaching to

Mulcahy, Robert

2001-01-01

423

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...

424

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

425

Links between Join Processing and Convex Geometry Christopher R  

E-print Network

, Ngo, Porat, Rudra, and R´e (NPRR) discovered the first relational join algorithm with worst]. In a recent survey with Ngo and Rudra [9], we simplified the algorithms and the argu- ments for such worst permission and/or a fee. Copyright 20XX ACM X-XXXXX-XX-X/XX/XX ...$10.00. Ngo, Ngo, and Rudra [7], we have

Pratt, Vaughan

426

INFORMING THE POLICY PROCESS WITH COGNITIVE MAPPING. (R825791)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

427

The r-Process Enriched Low Metallicity Giant HD 115444  

E-print Network

New high resolution, very high signal-to-noise spectra of ultra-metal-poor (UMP) giant stars HD 115444 and HD 122563 have been gathered with the High-Resolution Echelle Spectrometer of the McDonald Observatory 2.7m Telescope. With these spectra, line identification and model atmosphere analyses have been conducted, emphasizing the neutron-capture elements. Twenty elements with Z > 30 have been identified in the spectrum of HD 115444. This star is known to have overabundances of the neutron-capture elements, but it has lacked a detailed analysis necessary to compare with nucleosynthesis predictions. The new study features a line-by-line differential abundance comparison of HD 115444 with the bright, well-studied halo giant HD 122563. For HD 115444, the overall metallicity is [Fe/H]~ -3.0. The abundances of the light and iron-peak elements generally show the same pattern as other UMP stars (e.g. overdeficiencies of manganese and chromium, overabundances of cobalt), but the differential analysis indicates several nucleosynthesis signatures that are unique to each star.

Jenny Westin; Christopher Sneden; Bengt Gustafsson; John J. Cowan

1999-10-20

428

Parallel Processing in Amplitude Analysis  

E-print Network

electromagnetic interactions weak interactions strong interactions Quantum Chromodynamics (QCD) Quantum tube" model Energy density from "Lattice QCD" #12;M. R. Shepherd Parallel Processing Lecture 2 March 31 March 31, 2011 Hybrid Mesons · Conventional mesons: flux tube is in ground state · Hybrid mesons: flux

Evans, Hal

429

SPRINT: A new parallel framework for R  

PubMed Central

Background Microarray analysis allows the simultaneous measurement of thousands to millions of genes or sequences across tens to thousands of different samples. The analysis of the resulting data tests the limits of existing bioinformatics computing infrastructure. A solution to this issue is to use High Performance Computing (HPC) systems, which contain many processors and more memory than desktop computer systems. Many biostatisticians use R to process the data gleaned from microarray analysis and there is even a dedicated group of packages, Bioconductor, for this purpose. However, to exploit HPC systems, R must be able to utilise the multiple processors available on these systems. There are existing modules that enable R to use multiple processors, but these are either difficult to use for the HPC novice or cannot be used to solve certain classes of problems. A method of exploiting HPC systems, using R, but without recourse to mastering parallel programming paradigms is therefore necessary to analyse genomic data to its fullest. Results We have designed and built a prototype framework that allows the addition of parallelised functions to R to enable the easy exploitation of HPC systems. The Simple Parallel R INTerface (SPRINT) is a wrapper around such parallelised functions. Their use requires very little modification to existing sequential R scripts and no expertise in parallel computing. As an example we created a function that carries out the computation of a pairwise calculated correlation matrix. This performs well with SPRINT. When executed using SPRINT on an HPC resource of eight processors this computation reduces by more than three times the time R takes to complete it on one processor. Conclusion SPRINT allows the biostatistician to concentrate on the research problems rather than the computation, while still allowing exploitation of HPC systems. It is easy to use and with further development will become more useful as more functions are added to the framework. PMID:19114001

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

2008-01-01

430

Dynamical R-parity violation.  

PubMed

We present a new paradigm for supersymmetric theories with R-parity violation (RPV). At high scale, R parity is conserved in the visible sector but spontaneously broken in the supersymmetry-breaking sector. The breaking is then dynamically mediated to the visible sector and is manifested via nonrenormalizable operators at low energy. Consequently, RPV operators originate from the Khler potential rather than the superpotential, and are naturally suppressed by the supersymmetry-breaking scale, explaining their small magnitudes. A new set of nonholomorphic RPV operators is identified and found to often dominate over the standard RPV ones. We study the relevant low-energy constraints arising from baryon-number violating processes, proton decay, and flavor changing neutral currents, which may all be satisfied if a solution to the standard model flavor puzzle is incorporated. The chiral structure of the RPV operators implies new and distinct collider signatures, indicating the need to alter current techniques in searching for RPV at the LHC. PMID:24745404

Cski, Csaba; Kuflik, Eric; Volansky, Tomer

2014-04-01

431

257:1046-1049, 1989.Am J Physiol Regulatory Integrative Comp Physiol J. R. Layne, Jr, R. E. Lee, Jr and T. L. Heil  

E-print Network

, only the tree frog Hyla versicolor ex- tends this process by synthesizing glycerol from glycogen (10 in the heart rate of wood frogs (Rana sylvatica) JACK R. LAYNE, JR., RICHARD E. LEE, JR., AND THOMAS L. HEIL of wood frogs (Rana syluatica). Am. J. Physiol. 257 (Regulatory Integrative Comp.Physiol. 26): R1046-R1049

Lee Jr., Richard E.

432

Embedding R+R{sup 2} inflation in supergravity  

SciTech Connect

We find the natural embedding of the (R+R{sup 2}) inflationary model into the recently constructed F(R) supergravity. It gives a simple and viable realization of chaotic inflation in supergravity. The only requirement for a slow-roll inflation is the existence of the R{sup 3} term with an anomalously large coefficient in Taylor expansion of the F(R) function.

Ketov, Sergei V. [Department of Physics, Tokyo Metropolitan University, Minami-Ohsawa 1-1, Hachioji-shi, Tokyo 192-0397 (Japan); Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa-shi, Chiba 277-8568 (Japan); Starobinsky, Alexei A. [Landau Institute for Theoretical Physics, Moscow 119334 (Russian Federation); Research Center for the Early Universe (RESCEU), Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)

2011-03-15

433

Process description  

NASA Technical Reports Server (NTRS)

The production of hydrogen from coal by hydrogasification and subsequent steam hydrocarbon reforming was studied. Process heat and power requirements are supplied by an HTGR. The process is examined as a function of a maximum reforming (process) temperature of 922 K (1200 F) to 1367 K (2000 F). The major parameters for the five cases selected are summarized in a table. A fixed thermal capacity of 3000 MW for the HTGR heat source was used as a basis. The resulting hydrogen production rates and the corresponding hydrogen purity are also given in a table.

1975-01-01

434

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

435

South Dakota North Platte R.  

E-print Network

South Dakota Nebraska Index map North Platte R. South Platte R. Dismal R. Platte R. Study area 0 0 1 KILOMETER 1 MILE Scotts Bluff County Tri-St ate Canal Mitchell Canal North Platte River Enterprise 2002 Prepared in cooperation with the NORTH PLATTE NATURAL RESOURCES DISTRICT SIGNIFICANT FINDINGS

436

Assessment of Advanced Coal Gasification Processes  

NASA Technical Reports Server (NTRS)

This report represents a technical assessment of the following advanced coal gasification processes: AVCO High Throughput Gasification (HTG) Process; Bell Single-Stage High Mass Flux (HMF) Process; Cities Service/Rockwell (CS/R) Hydrogasification Process; Exxon Catalytic Coal Gasification (CCG) Process. Each process is evaluated for its potential to produce SNG from a bituminous coal. In addition to identifying the new technology these processes represent, key similarities/differences, strengths/weaknesses, and potential improvements to each process are identified. The AVCO HTG and the Bell HMF gasifiers share similarities with respect to: short residence time (SRT), high throughput rate, slagging and syngas as the initial raw product gas. The CS/R Hydrogasifier is also SRT but is non-slagging and produces a raw gas high in methane content. The Exxon CCG gasifier is a long residence time, catalytic, fluidbed reactor producing all of the raw product methane in the gasifier. The report makes the following assessments: 1) while each process has significant potential as coal gasifiers, the CS/R and Exxon processes are better suited for SNG production; 2) the Exxon process is the closest to a commercial level for near-term SNG production; and 3) the SRT processes require significant development including scale-up and turndown demonstration, char processing and/or utilization demonstration, and reactor control and safety features development.

McCarthy, John; Ferrall, Joseph; Charng, Thomas; Houseman, John

1981-01-01

437

Process Technology  

NSDL National Science Digital Library

In this video adapted from ATETV, learn about the field of process technology and what it takes to work in the field from the perspectives of a student, a community college professor, and an industry specialist.

Foundation, Wgbh E.

2010-07-11

438

COLLAGEN PROCESSING  

Technology Transfer Automated Retrieval System (TEKTRAN)

Collagen dispersions, produced from fibrils recovered from milled bovine collagen, have shown promise in environmental remediation in applications as settling aids, filtration aids, fractionation media, oil drop stabilizers, and water purification aids. Macroporous structures, processed by controll...

439

Image Processing  

Microsoft Academic Search

The field of image processing addresses handling and analysis of images for many purposes using a large number of techniques\\u000a and methods. The applications of image processing range from enhancement of the visibility of certain organs in medical images\\u000a to object recognition for handling by industrial robots and face recognition for identification at airports, but also searching\\u000a for images in

Ferdi van der Heijden; Luuk Spreeuwers; H. M. Blanken; A. P. Vries de; H. E. Blok; L Feng

2007-01-01

440

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

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