1,027 research outputs found

    Fock space relativistic coupled-Cluster calculations of Two-Valence Atoms

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    We have developed an all particle Fock-space relativistic coupled-cluster method for two-valence atomic systems. We then describe a scheme to employ the coupled-cluster wave function to calculate atomic properties. Based on these developments we calculate the excitation energies, magnetic hyperfine constants and electric dipole matrix elements of Sr, Ba and Yb. Further more, we calculate the electric quadrupole HFS constants and the electric dipole matrix elements of Sr+^+, Ba+^+ and Yb+^+. For these we use the one-valence coupled-cluster wave functions obtained as an intermediate in the two-valence calculations. We also calculate the magnetic dipole hyperfine constants of Yb+^+.Comment: 23 pages, 12 figures, 10 tables typos are corrected and some minor modifications in some of the section

    A regional ocean circulation model for the mid-Cretaceous North Atlantic Basin: implications for black shale formation

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    High concentrations of organic matter accumulated in marine sediments during Oceanic Anoxic Events (OAEs) in the Cretaceous. Model studies examining these events invariably make use of global ocean circulation models. In this study, a regional model for the North Atlantic Basin during OAE2 at the Cenomanian-Turonian boundary has been developed. A first order check of the results has been performed by comparison with the results of a recent global Cenomanian CCSM3 run, from which boundary and initial conditions were obtained. The regional model is able to maintain tracer patterns and to produce velocity patterns similar to the global model. The sensitivity of the basin tracer and circulation patterns to changes in the geometry of the connections with the global ocean is examined with three experiments with different bathymetries near the sponges. Different geometries turn out to have little effect on tracer distribution, but do affect circulation and upwelling patterns. The regional model is also used to test the hypothesis that ocean circulation may have been behind the deposition of black shales during OAEs. Three scenarios are tested which are thought to represent pre-OAE, OAE and post-OAE situations. Model results confirm that Pacific intermediate inflow together with coastal upwelling could have enhanced primary production during OAE2. A low sea level in the pre-OAE scenario could have inhibited large scale black shale formation, as could have the opening of the Equatorial Atlantic Seaway in the post-OAE scenario

    Ammonia Emission, Manure Nutrients and Egg Production of Laying Hens Fed Distiller Dried Grain Diets

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    A USDA Natural Resources Conservation Service, Conservation Innovation Grant project coordinated by the United Egg Producers (UEP) conducted concurrent demonstrations in Iowa and Pennsylvania (PA) at commercial laying hen facilities. The goal was to document manure nutrient and gas emission improvements through the use of dried distiller’s grain with solubles (DDGS) diets and/or other dietary modifications while maintaining or improving hen productivity. Results of the PA trial are presented here. Diets containing 10% corn DDGS with (D+P) or without (D) the probiotic Provalen™ were compared to a corn-soybean based control diet (CON). The isocaloric, amino acid balanced diets were fed to three groups of 39,800 Lohmann hens in one house. Hens were 20-65 wk of age with each diet provided to 2 of 6 rows of stacked cages with manure belts (six decks high). Feed intake, water consumption, hen body weight (BW), egg production (EP,) egg case weight, mortality, feed cost (FC), and egg income (EI) were provided weekly by the cooperating egg company. Replicated monthly data, including egg weight (EW), albumen height (AH), Haugh units (HU), yolk color (YC), shell strength (SS) and shell thickness (ST), were determined from eggs collected from six 4-cage sections of hens on each diet. Replicated monthly samples of hen manure (fresh and from storage) were analyzed for moisture and major nutrients. Ammonia (NH3) gas measurements utilized a non-steady state flux chamber method coupled with photoacoustic infrared gas analyzer. There was no clear trend in the magnitude of NH3 emissions relative to the diets within the hen house as measured on the manure belt. At 32 and 36 wks of age, NH3 emissions were significantly (P \u3c 0.10) higher in D while D+P and CON were lower and similar. At 48 and 52 wks, NH3 emissions from D were similar to D+P and significantly lower than CON. Emission rate from belt manure averaged 0.42 ±0.025 g bird-1 d-1 for all treatments and dates. There was no significant impact of diet on BW, EW, HU, SS, or ST (P =0.10 to 0.66), however, CON hens had lower EP, AH, and YC compared to D and D+P hens (P=0.05). Fresh manure total phosphorus (P2O5) was higher for CON samples (P \u3c 0.05) while other major agronomic nutrients and moisture were not significantly different among treatments. Stored CON manure samples had increased moisture and NH4-N compared to those of D and D+P treatments (P \u3c 0.10). Weekly EI minus FC averaged 6,146,6,146, 6,215, and $6,209 for the CON, D, and D+P diets, respectively

    Recent Radiation Test Results for Trench Power MOSFETs

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    Single-event effect (SEE) radiation test results are presented for various trench-gate power MOSFETs. The heavy-ion response of the first (and only) radiation-hardened trench-gate power MOSFET is evaluated: the manufacturer SEE response curve is verified and importantly, no localized dosing effects are measured, distinguishing it from other, non-hardened trench-gate power MOSFETs. Evaluations are made of n-type commercial and both n- and p-type automotive grade trench-gate device using ions comparable to of those on the low linear energy transfer (LET) side of the iron knee of the galactic cosmic ray spectrum, to explore suitability of these parts for missions with higher risk tolerance and shorter duration, such as CubeSats. Part-to-part variability of SEE threshold suggests testing with larger sample sizes and applying more aggressive derating to avoid on-orbit failures. The n-type devices yielded expected localized dosing effects including when irradiated in an unbiased (0-V) configuration, adding to the challenge of inserting these parts into space flight missions

    Mutually Penetrating Motion of Self-Organized 2D Patterns of Soliton-Like Structures

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    Results of numerical simulations of a recently derived most general dissipative-dispersive PDE describing evolution of a film flowing down an inclined plane are presented. They indicate that a novel complex type of spatiotemporal patterns can exist for strange attractors of nonequilibrium systems. It is suggested that real-life experiments satisfying the validity conditions of the theory are possible: the required sufficiently viscous liquids are readily available.Comment: minor corrections, 4 pages, LaTeX, 6 figures, mpeg simulations available upon or reques

    Recent Radiation Test Results for Power MOSFETs

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    Single-event effect (SEE) and total ionizing dose (TID) test results are presented for various hardened and commercial power metal-oxide-semiconductor field effect transistors (MOSFETs), including vertical planar, trench, superjunction, and lateral process designs

    “Universidade da Democracia: A universidade comunitária americana no Século XXI”: Delimitação da discussão.

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    In this manuscript, the guest editors of the EPAA Special Issue on “Democracy’s College: The American Community College in the 21st Century”: a) introduce the background, history, and context of community colleges in the larger higher education landscape; b) summarize the three research papers and two video commentaries that were peer-reviewed and selected for inclusion in this special issue; and, c) discuss the individual contributions and major themes across the selected papers. Their importance is discussed in terms of each paper’s insights for the general research on this topic and each paper’s potential to inform community college research, practice, and policy.En este trabajo, las editoras de este número especial de EPAA en la "Universidad de la Democracia: La universidad  comunitaria en el siglo XXI: a) presenta los antecedentes, la historia, el contexto de la universidad  comunitaria (en inglés Community Colleges) en el escenario más amplio de la educación superior b) presenta un resumen de los tres artículos de investigación y de los dos videos con comentarios que han sido evaluados por pares y seleccionados para formar parte de este número especial, y c) analiza las contribuciones individuales y los principales temas transversales a los trabajos seleccionados. Se discute la relevancia de cada trabajo en términos de las ideas que cada uno aporta a la labor de investigación general sobre este tema y el potencial de cada trabajo para informar a la investigación, la práctica y la política en las universidades  comunitarias.Neste texto, os editores convidados do Número Especial da AAPE sobre “Universidade da Democracia: A universidade comunitária americana no Século XXI”: a) introduz o plano de fundo, história, e contexto das universidades comunitárias (em inglês Community Colleges) no cenário mais amplo da educação superior; b) resume os três trabalhos de investigação e os dois comentários a vídeos que foram revistos por pares e selecionados para integrar este número especial; e, c) discute as contribuições individuais e os principais temas transversais aos trabalhos selecionados. A sua importância é discutida em termos das ideias que cada um dos trabalhos traz para a pesquisa geral sobre este tema e o potencial de cada trabalho para informar a investigação, as práticas e as políticas sobre faculdades comunitárias

    Interdistrict and Charter School Mobility in Arizona: Understanding the Dynamics of Public School Choice

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    We investigate the mobility patterns of elementary students enrolled in Arizona’s traditional public school districts and charter schools. We address interdistrict and charter school mobility simultaneously. Most student movement is interdistrict or between school districts. In Arizona, interdistrict mobility has played a greater role in creating and sustaining the “educational market” than charter schools. There is also a substantial amount of student movement from charter schools to school districts. Regression analyses suggested that the relationship between demographic and achievement variables and the different types of student mobility differed across the two sectors. We also document regional differences in mobility patterns, which indicate that education markets vary considerably across and even within local contexts

    RH1021BMH-10 Precision 10 V Reference Total Ionizing Dose Test Report

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    The purpose of this test was to validate the Analog Devices (ADI) RH1021BMH-10 flight lot for use in the fabrication of Europa Clipper Propulsion subsystem flight hardware. This test shall serve as the radiation lot acceptance test (RLAT) for this flight lot with wafer lot number 769658.1 and lot date code (LDC) 1430A. Low dose rate (LDR) irradiations were performed in this test so that the device susceptibility to enhanced low dose rate sensitivity (ELDRS) could be determined
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