4,619 research outputs found

    Ion sputter textured graphite electrode plates

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    A specially textured surface of pyrolytic graphite exhibits extremely low yields of secondary electrons and reduced numbers of reflected primary electrons after impingement of high energy primary electrons. Electrode plates of this material are used in multistage depressed collectors. An ion flux having an energy between 500 iV and 1000 iV and a current density between 1.0 mA/sq cm and 6.0 mA/sq cm produces surface roughening or texturing which is in the form of needles or spires. Such textured surfaces are especially useful as anode collector plates in high tube devices

    Ion sputter textured graphite

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    A specially textured surface of pyrolytic graphite exhibits extremely low yields of secondary electrons and reduced numbers of reflected primary electrons after impingement of high energy primary electrons. An ion flux having an energy between 500 eV and 1000 eV and a current density between 1.0 mA/sq cm and 6.0 mA/sq cm produces surface roughening or texturing which is in the form of needles or spines. Such textured surfaces are especially useful as anode collector plates in high efficiency electron tube devices

    The Unintended Consequences of the International Women\u27s Movement: Medicalizing Rape in the Democratic Republic of Congo

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    The legal advancements made by western feminists from the 1960s continuing today mark a distinct shift for both the women\u27s movement and mainstream radical feminist philosophy. This project examines the unintended consequences of the rise of the international women\u27s movement as American feminists brought the law to bear as the primary instrument for reform to eradicate rape and violence against women. As contemporary political scholars demonstrate, legal remediation further codifies gender inequality and protective tropes that sexualize women\u27s injury. Chapter 2 and 3 examines the intensified feminist efforts to criminalize domestic abuse at an international level, first at the United Nations (1980s) and later, sexual violence during wartime in international criminal law (1990s). In practice, state legislation to protect women from violence is often used as a vehicle to advance conservative political agendas. Two anthropological case studies explore these policies in action: Algerian women\u27s access to humanitarian asylum in France and specialized humanitarian medical care provided to raped women in the Democratic Republic of Congo. One pressing conclusion to draw from both studies is that women\u27s full citizenship status is being threatened by conservative notions of women\u27s worth being defined in terms of her chastity. Chapter 4 examines the highly publicized humanitarian medical response to mass rape in Congo and explores the colonially derived racial hierarchy that underlies many humanitarian missions. In the interest of circumventing state power over sexuality and therefore removing the sexual stigma from rape in legal terms, this paper engages with Michel Foucault\u27s argument that the crime of rape be desexualized and placed on a spectrum of degrees of assault

    Interprofessional education for first year psychology students: career plans, perceived relevance and attitudes

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    Undergraduate psychology students have been largely excluded from interprofessional education (IPE) initiatives. In contrast to many health professions, undergraduate psychology students do not engage in work placements as part of their degree, and many enter careers outside the health care context. However, the collaborative skills gained through an IPE experience may well be beneficial to students who work in this wider context. This research examines whether undergraduate psychology students’ views of IPE vary according to their planned career directions, and if so, whether the perceived relevance of IPE mediates the relationships. A sample of 188 Australian university undergraduate psychology students completed an online questionnaire following completion of a first-year IPE health sciences program. Path analysis indicated that psychology students’ attitudes towards IPE are associated with both professional identification and practitioner orientation, fully mediated through the perceived relevance of IPE to future career and study plans. Stronger professional identification and practitioner orientation were associated with greater perceived relevance and more positive and less negative attitudes towards IPE. Placing a stronger emphasis on the generalizability of IP skills taught may increase students’ awareness of the relevance outside of the health context, reducing disengagement of students planning alternative careers

    High-Energy sources before INTEGRAL -- INTEGRAL reference catalog --

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    We describe the INTEGRAL reference catalog which classifies previously known bright X-ray and gamma-ray sources before the launch of INTEGRAL. These sources are, or have been at least once, brighter than ~1 mCrab above 3 keV, and are expected to be detected by INTEGRAL. This catalog is being used in the INTEGRAL Quick Look Analysis to discover new sources or significantly variable sources. We compiled several published X-ray and gamma-ray catalogs, and surveyed recent publications for new sources. Consequently, there are 1122 sources in our INTEGRAL reference catalog. In addition to the source positions, we show an approximate spectral model and expected flux for each source, based on which we derive expected INTEGRAL counting rates. Assuming the default instrument performances and at least ~10^5 sec exposure time for any part of the sky, we expect that INTEGRAL will detect at least ~700 sources below 10 keV and ~400 sources above 20 keV over the mission life.Comment: Accepted to A&A Letter INTEGRAL special issu

    The Active Nucleus of IC4970: A Nearby Example of Merger-Induced Cold-Gas Accretion

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    We present results from Chandra X-ray and Spitzer mid-infrared observations of the interacting galaxy pair NGC6872/IC4970 in the Pavo galaxy group and show that the smaller companion galaxy IC4970 hosts a highly obscured active galactic nucleus (AGN). The 0.5-10 keV X-ray luminosity of the nucleus is variable, increasing by a factor 2.9 to 1.7 x 10^{42} erg/s (bright state) on ~100 ks timescales. The X-ray spectrum of the is heavily absorbed (N_H = 3 x 10^{23} cm^{-2}) for power law models with Gamma = 1.5-2.0 and shows a clear 6.4 keV Fe Kalpha line with equivalent width of 144-195 eV. Limits on the diffuse emission in IC4970 from Chandra X-ray data suggest that the available power from Bondi accretion of hot interstellar gas may be an order of magnitude too small to power the AGN. Spitzer images show that 8 micron nonstellar emission is concentrated in the central 1 kpc of IC4970, consistent with high obscuration in this region. The mid-infrared colors of the nucleus are consistent with those expected for a highly obscured AGN. Taken together these data suggest that the nucleus of IC4970 is a Seyfert 2, triggered and fueled by cold material supplied to the central supermassive black hole as a result of the off-axis collision of IC4970 with the cold-gas rich spiral galaxy NGC6872.Comment: 10 pages, 9 figures, submitted to ApJ, MIR flux conversion error corrected in Table 4, MIR colors and paper text unchange

    Sustained Isometric Wrist Flexion and Extension Maximal Voluntary Contractions Similarly Impair Hand-Tracking Accuracy in Young Adults Using a Wrist Robot

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    Due to their stabilizing role, the wrist extensor muscles demonstrate an earlier onset of performance fatigability and may impair movement accuracy more than the wrist flexors. However, minimal fatigue research has been conducted at the wrist. Thus, the purpose of this study was to examine how sustained isometric contractions of the wrist extensors/flexors influence hand-tracking accuracy. While gripping the handle of a three-degrees-of-freedom wrist manipulandum, 12 male participants tracked a 2:3 Lissajous curve (±32° wrist flexion/extension; ±18° radial/ulnar deviation). A blue, circular target moved about the trajectory and participants tracked the target with a yellow circle (corresponding to the handle's position). Five baseline tracking trials were performed prior to the fatiguing task. Participants then exerted either maximal wrist extension or flexion force (performed on separate days) against a force transducer until they were unable to maintain 25% of their pre-fatigue maximal voluntary contraction (MVC). Participants then performed 7 tracking trials from immediately post-fatigue to 10 min after. Performance fatigability was assessed using various metrics to account for errors in position-tracking, error tendencies, and movement smoothness. While there were no differences in tracking error between flexion/extension sessions, tracking error significantly increased immediately post-fatigue (Baseline: 1.40 ± 0.54°, Post-fatigue: 2.02 ± 0.51°, P < 0.05). However, error rapidly recovered, with no differences in error from baseline after 1-min post-fatigue. These findings demonstrate that sustained isometric extension/flexion contractions similarly impair tracking accuracy of the hand. This work serves as an important step to future research into workplace health and preventing injuries of the distal upper-limb

    X-ray total mass estimate for the nearby relaxed cluster A3571

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    We constrain the total mass distribution in the cluster A3571, combining spatially resolved ASCA temperature data with ROSAT imaging data with the assumption that the cluster is in hydrostatic equilibrium. The total mass within r_500 (1.7/h_50 Mpc) is M_500 = 7.8[+1.4,-2.2] 10^14/ h_50 Msun at 90% confidence, 1.1 times smaller than the isothermal estimate. The Navarro, Frenk & White ``universal profile'' is a good description of the dark matter density distribution in A3571. The gas density profile is shallower than the dark matter profile, scaling as r^{-2.1} at large radii, leading to a monotonically increasing gas mass fraction with radius. Within r_500 the gas mass fraction reaches a value of f_gas = 0.19[+0.06,-0.03] h_50^{-3/2} (90% confidence errors). Assuming that this value of f_gas is a lower limit for the the universal value of the baryon fraction, we estimate the 90% confidence upper limit of the cosmological matter density to be Omega_m < 0.4.Comment: 10 pages, 4 figures, accepted by Ap
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