1,379 research outputs found

    An updated feminist view of intimate partner violence

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    In this article, we explore intimate partner violence (IPV) from an intersectional, feminist perspective. We describe how an updated feminist view guides us to a perspective on IPV that is more strongly grounded in an anti-oppressive, non-violent, socially just feminist stance than a second-wave gender-essential feminist stance that suggests that patriarchy is the cause of IPV. At the time we began to work together it seemed that a researcher had to be identified as a “family violence” researcher or a “feminist” researcher of violence against women, and that it wasn’t possible to be a feminist researcher who looked beyond patriarchy as the cause of IPV. We advocate critically thinking about essentialist practices in clinical work so that we can maintain an anti-oppressive, socially just, non-violent approach to working with clients who experience IPV

    The Influence of High-Energy Lithium Ion Irradiation on Electrical Characteristics of Silicon and GaAs Solar Cells

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    Space-grade Si and GaAs solar cells were irradiated with 15 & 40 MeV Li ions. Illuminated (AM0 condition) and unilluminated I-V curves reveal that the effect of high-energy Li ion irradiation has produced similar effects to that of proton irradiation. However, an additional, and different, defect mechanism is suggested to dominate in the heavier-ion results. Comparison is made with proton-irradiated solar-cell work and with non-ionizing energy-loss (NIEL) radiation-damage models.Comment: 8 pages, 12 figures, Data presented at 2006 NSREC, Final Version to be published in IEEE Transactions on Nuclear Science, 53, NO. 6, December 2006. Index Terms: GaAs, Ion-irradiation, Lithium, NIEL, Photovoltaic cells, Radiation effects, Silico

    The genetic basis of energy conservation in the sulfate-reducing bacterium Desulfovibrio alaskensis G20.

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    Sulfate-reducing bacteria play major roles in the global carbon and sulfur cycles, but it remains unclear how reducing sulfate yields energy. To determine the genetic basis of energy conservation, we measured the fitness of thousands of pooled mutants of Desulfovibrio alaskensis G20 during growth in 12 different combinations of electron donors and acceptors. We show that ion pumping by the ferredoxin:NADH oxidoreductase Rnf is required whenever substrate-level phosphorylation is not possible. The uncharacterized complex Hdr/flox-1 (Dde_1207:13) is sometimes important alongside Rnf and may perform an electron bifurcation to generate more reduced ferredoxin from NADH to allow further ion pumping. Similarly, during the oxidation of malate or fumarate, the electron-bifurcating transhydrogenase NfnAB-2 (Dde_1250:1) is important and may generate reduced ferredoxin to allow additional ion pumping by Rnf. During formate oxidation, the periplasmic [NiFeSe] hydrogenase HysAB is required, which suggests that hydrogen forms in the periplasm, diffuses to the cytoplasm, and is used to reduce ferredoxin, thus providing a substrate for Rnf. During hydrogen utilization, the transmembrane electron transport complex Tmc is important and may move electrons from the periplasm into the cytoplasmic sulfite reduction pathway. Finally, mutants of many other putative electron carriers have no clear phenotype, which suggests that they are not important under our growth conditions, although we cannot rule out genetic redundancy

    HST Images Flash Ionization of Old Ejecta by the 2011 Eruption of Recurrent Nova T Pyxidis

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    T Pyxidis is the only recurrent nova surrounded by knots of material ejected in previous outbursts. Following the eruption that began on 2011 April 14.29, we obtained seven epochs (from 4 to 383 days after eruption) of Hubble Space Telescope narrowband Ha images of T Pyx . The flash of radiation from the nova event had no effect on the ejecta until at least 55 days after the eruption began. Photoionization of hydrogen located north and south of the central star was seen 132 days after the beginning of the eruption. That hydrogen recombined in the following 51 days, allowing us to determine a hydrogen atom density of at least 7e5 cm^-3 - at least an order of magnitude denser than the previously detected, unresolved [NII] knots surrounding T Pyx. Material to the northwest and southeast was photoionized between 132 and 183 days after the eruption began. 99 days later that hydrogen had recombined. Both then (282 days after outburst) and 101 days later, we detected almost no trace of hydrogen emission around T Pyx. There is a large reservoir of previously unseen, cold diffuse hydrogen overlapping the previously detected, [NII] - emitting knots of T Pyx ejecta. The mass of this newly detected hydrogen is probably an order of magnitude larger than that of the [NII] knots. We also determine that there is no significant reservoir of undetected ejecta from the outer boundaries of the previously detected ejecta out to about twice that distance, near the plane of the sky. The lack of distant ejecta is consistent with the Schaefer et al (2010) scenario for T Pyx, in which the star underwent its first eruption within five years of 1866 after many millennia of quiescence, followed by the six observed recurrent nova eruptions since 1890. This lack of distant ejecta is not consistent with scenarios in which T Pyx has been erupting continuously as a recurrent nova for many centuries or millennia.Comment: 27 pages, 10 figures, submitted to the Astrophysical Journa

    Influence of Farming Culture on Rituals of North Malabar Region of Kerala State

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    This paper forms a part of the theses entitled “Influence of farming culture on the folk arts and rituals of North Malabar region of Kerala state”. The objective of the study was to identify specific elements as influenced by farming culture and to assess their scientific rationale, if any. The research design followed was exploratory and ex post facto in nature. The study revealed that most of the rituals have been originated from an ancient agrarian society which had a deep-rooted stand in farming culture. It was also seen that these rituals, through superstitions, taboos, etc., prompted the public to conserve the ecosystem. They promoted eco-friendly sustainable farming supplementing the endeavor towards a greener Kerala

    Functional genomics with a comprehensive library of transposon mutants for the sulfate-reducing bacterium Desulfovibrio alaskensis G20.

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    UnlabelledThe genomes of sulfate-reducing bacteria remain poorly characterized, largely due to a paucity of experimental data and genetic tools. To meet this challenge, we generated an archived library of 15,477 mapped transposon insertion mutants in the sulfate-reducing bacterium Desulfovibrio alaskensis G20. To demonstrate the utility of the individual mutants, we profiled gene expression in mutants of six regulatory genes and used these data, together with 1,313 high-confidence transcription start sites identified by tiling microarrays and transcriptome sequencing (5' RNA-Seq), to update the regulons of Fur and Rex and to confirm the predicted regulons of LysX, PhnF, PerR, and Dde_3000, a histidine kinase. In addition to enabling single mutant investigations, the D. alaskensis G20 transposon mutants also contain DNA bar codes, which enables the pooling and analysis of mutant fitness for thousands of strains simultaneously. Using two pools of mutants that represent insertions in 2,369 unique protein-coding genes, we demonstrate that the hypothetical gene Dde_3007 is required for methionine biosynthesis. Using comparative genomics, we propose that Dde_3007 performs a missing step in methionine biosynthesis by transferring a sulfur group to O-phosphohomoserine to form homocysteine. Additionally, we show that the entire choline utilization cluster is important for fitness in choline sulfate medium, which confirms that a functional microcompartment is required for choline oxidation. Finally, we demonstrate that Dde_3291, a MerR-like transcription factor, is a choline-dependent activator of the choline utilization cluster. Taken together, our data set and genetic resources provide a foundation for systems-level investigation of a poorly studied group of bacteria of environmental and industrial importance.ImportanceSulfate-reducing bacteria contribute to global nutrient cycles and are a nuisance for the petroleum industry. Despite their environmental and industrial significance, the genomes of sulfate-reducing bacteria remain poorly characterized. Here, we describe a genetic approach to fill gaps in our knowledge of sulfate-reducing bacteria. We generated a large collection of archived, transposon mutants in Desulfovibrio alaskensis G20 and used the phenotypes of these mutant strains to infer the function of genes involved in gene regulation, methionine biosynthesis, and choline utilization. Our findings and mutant resources will enable systematic investigations into gene function, energy generation, stress response, and metabolism for this important group of bacteria

    Electrochemically Impregnated Aluminum-Stabilized α-Nickel Hydroxide Electrodes

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    Nickel-positive electrodes obtained by electrochemical impregnation of aluminum-substituted α-nickel hydroxide are found to deliver a reversible discharge capacity of ca. 450 mAh/g. This is much higher than the capacity of β-nickel hydroxide electrodes 200 mAh/g: this work; 225 mAh/g: Dixit et al., J. Power Sources, 63, 167 (1996) prepared under identical conditions and pasted electrodes comprising cobalt-doped nickel hydroxide 345 mAh/g: Faure et al., J. Power Sources, 36, 497 (1991). These observations suggest that the theoretical target-capacity for high-performance nickel-positive electrodes must be revised from the currently accepted value of 289 mAh/g (1e exchange) to 491 mAh/g 1.7e exchange: Corrigan and Knight, J. Electrochem. Soc., 136, 613 (1989). © 1999 The Electrochemical Society. S1099-0062(98)08-044-4. All rights reserved

    Evolution of 3D Boson Stars with Waveform Extraction

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    Numerical results from a study of boson stars under nonspherical perturbations using a fully general relativistic 3D code are presented together with the analysis of emitted gravitational radiation. We have constructed a simulation code suitable for the study of scalar fields in space-times of general symmetry by bringing together components for addressing the initial value problem, the full evolution system and the detection and analysis of gravitational waves. Within a series of numerical simulations, we explicitly extract the Zerilli and Newman-Penrose scalar Ψ4\Psi_4 gravitational waveforms when the stars are subjected to different types of perturbations. Boson star systems have rapidly decaying nonradial quasinormal modes and thus the complete gravitational waveform could be extracted for all configurations studied. The gravitational waves emitted from stable, critical, and unstable boson star configurations are analyzed and the numerically observed quasinormal mode frequencies are compared with known linear perturbation results. The superposition of the high frequency nonspherical modes on the lower frequency spherical modes was observed in the metric oscillations when perturbations with radial and nonradial components were applied. The collapse of unstable boson stars to black holes was simulated. The apparent horizons were observed to be slightly nonspherical when initially detected and became spherical as the system evolved. The application of nonradial perturbations proportional to spherical harmonics is observed not to affect the collapse time. An unstable star subjected to a large perturbation was observed to migrate to a stable configuration.Comment: 26 pages, 12 figure

    Effect of an extract of Centella asiatica on the biodistribution of sodium pertechnetate (Na<sup>99m</sup>TcO<sub>4</sub>) and on the fixation of radioactivity on blood constituents

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    This study evaluates the effects of an acute treatment with a Centella asiatica (CA) extract on the biodistribution of the radiopharmaceutical Na99mTcO4 and on the fixation of technetium-99m on blood constituents. Wistar rats were treated with CA extract and, 1 hour after, Na99mTcO4 was administered; organs/tissues were withdrawn and weighted. The radioactivity was counted to calculate the percentage of activity per gram (%ATI/g). Also, blood samples were withdrawn, plasma (P), blood cells (BC), insoluble fraction (IF) and soluble fractions of P and BC were isolated and the radioactivity was counted to calculate the percentage of activity (%ATI). Data indicated that the acute treatment with CA extract changed significantly (p99mTcO4 and the fixation of the technetium-99m on blood constituents in an acute treatment
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