1,314 research outputs found

    Palestinian Refugees in Gaza

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    Events since Arthur Helton\u27s death - including the change in leadership of the Palestinian Authority and the Israeli proposal for disengagement from Gaza make it even timelier to examine some practical solutions. For improving Palestinian lives in the short term, much can be learned from the approaches taken in other refugee situations. This Article begins with background information on Palestinian refugees in Gaza. It then discusses Israeli plans for disengagement from Gaza. In the following section, the Article reviews options for addressing the problems faced by Palestinian refugees in Gaza, utilizing the broader literature devoted to the integration of refugees and displaced persons in post-conflict and post-occupation societies. It concludes with an agenda of action for the international community, Palestinian Authority, and Israel

    Application of the Method of Stein and Sanders to the Calculation of Vibration Characteristics of a 45 deg Delta-Wing Specimen

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    Generalized influence coefficients are calculated by the method of NACA TN 3640 for a large-scale, built-up, 450 delta-wing specimen. These are used together with appropriate generalized masses to obtain the natural modes and frequencies in symmetric and antisymmetric free-free vibration. The resulting frequencies are compared with those obtained experimentally and are found to be consistently high. Possible sources of the disparities are discussed

    A wetting and drying scheme for ROMS

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    This paper is not subject to U.S. copyright. The definitive version was published in Computers & Geosciences 58 (2013): 54-61, doi:10.1016/j.cageo.2013.05.004.The processes of wetting and drying have many important physical and biological impacts on shallow water systems. Inundation and dewatering effects on coastal mud flats and beaches occur on various time scales ranging from storm surge, periodic rise and fall of the tide, to infragravity wave motions. To correctly simulate these physical processes with a numerical model requires the capability of the computational cells to become inundated and dewatered. In this paper, we describe a method for wetting and drying based on an approach consistent with a cell-face blocking algorithm. The method allows water to always flow into any cell, but prevents outflow from a cell when the total depth in that cell is less than a user defined critical value. We describe the method, the implementation into the three-dimensional Regional Oceanographic Modeling System (ROMS), and exhibit the new capability under three scenarios: an analytical expression for shallow water flows, a dam break test case, and a realistic application to part of a wetland area along the Georgia Coast, USA.We acknowledge support for studies demonstrated in this manuscript that were supported by the National Science Foundation,Division of Industrial Innovation and Partnerships (IIP)under the 3470Z. Defne etal./ Renewable Energy 36(2011)3461e3471 Partnerships for Innovation Program Grant IIP-0332613,and from the Strategic Energy Institute at Georgia Institute of Technology via a Creating Energy Options grant and the 104B Georgia Water Resources Institute Funding Program,and also by the Department of Energy,Wind and Hydropower Technologies Program award number DE-FG36-08GO18174 and by the state of Georgia

    Electron spin coherence in metallofullerenes: Y, Sc and La@C82

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    Endohedral fullerenes encapsulating a spin-active atom or ion within a carbon cage offer a route to self-assembled arrays such as spin chains. In the case of metallofullerenes the charge transfer between the atom and the fullerene cage has been thought to limit the electron spin phase coherence time (T2) to the order of a few microseconds. We study electron spin relaxation in several species of metallofullerene as a function of temperature and solvent environment, yielding a maximum T2 in deuterated o-terphenyl greater than 200 microseconds for Y, Sc and La@C82. The mechanisms governing relaxation (T1, T2) arise from metal-cage vibrational modes, spin-orbit coupling and the nuclear spin environment. The T2 times are over 2 orders of magnitude longer than previously reported and consequently make metallofullerenes of interest in areas such as spin-labelling, spintronics and quantum computing.Comment: 5 pages, 4 figure

    Violence Increases Psychological Distress Among Women Trafficking Survivors in Ghana

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    Human trafficking is a crime that is often shaped by violence, particularly for women who are trafficked. Additionally, trafficking survivors often report severe psychological distress, though research on the causes of this psychological distress is lacking, as there is little longitudinal data available on trafficking survivors. Informed by past literature on the links between violence and mental health among other traumatized groups of women, we investigate how experiences of violence influence posttraumatic stress, depression, and suicide ideation among a unique longitudinal sample of 116 labor-trafficked women in Ghana. We find that experiencing sexual violence while being trafficked is associated with higher levels of both depression and posttraumatic stress years after the trafficking period ended. This indicates both the long-term effects of stress and the enduring nature of psychological distress among the women in this study. Our analytic account of how violent experiences while trafficked impact mental health over the period of reintegration contributes to the general literature on violence and mental health among women, as well as to literature on the health implications of human traffickin

    1RXS J232953.9+062814: A Dwarf Nova with a 64-minute Orbital Period and a Conspicuous Secondary Star

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    We present spectroscopy and time-series photometry of the newly discovered dwarf nova 1RXS J232953.9+062814. Photometry in superoutburst reveals a superhump with a period of 66.06(6) minutes. The low state spectrum shows Balmer and HeI emission on a blue continuum, and in addition shows a rich absorption spectrum of type K4 +- 2. The absorption velocity is modulated sinusoidally at P_orb = 64.176(5) min, with semi-amplitude K = 348(4) km/s. The low-state light curve is double-humped at this period, and phased as expected for ellipsoidal variations. The absorption strength does not vary appreciably around the orbit. The orbital period is shorter than any other cataclysmic variable save for a handful of helium-star systems and V485 Centauri (59 minutes). The secondary is much hotter than main sequence stars of similar mass, but is well-matched by helium-enriched models, indicating that the secondary evolved from a more massive progenitor. A preliminary calculation in which a 1.2 solar-mass star begins mass transfer near the end of H burning matches this system's characteristics remarkably well.Comment: accepted to Astrophysical Journal Letters; 14 pages, 3 eps figures + 1 jpg greyscale figur

    Parallax and Distance Estimates for Fourteen Cataclysmic Variable Stars

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    I used the 2.4 m Hiltner telescope at MDM Observatory in an attempt to measure trigonometric parallaxes for 14 cataclysmic variable stars. Techniques are described in detail. In the best cases the parallax uncertainties are below 1 mas, and significant parallaxes are found for most of the program stars. A Bayesian method which combines the parallaxes together with proper motions and absolute magnitude constraints is developed and used to derive distance estimates and confidence intervals. The most precise distance derived here is for WZ Sge, for which I find 43.3 (+1.6, -1.5) pc. Six Luyten Half-Second stars with previous precise parallax measurements were re-measured to test the techniques, and good agreement is found.Comment: 33 pages, 3 figures. Astronomical Journal, accepte

    Using a composite grid approach in a complex coastal domain to estimate estuarine residence time

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    This paper is not subject to U.S. copyright. The definitive version was published in Computers & Geosciences 36 (2010): 921-935, doi:10.1016/j.cageo.2009.11.008.We investigate the processes that influence residence time in a partially mixed estuary using a three-dimensional circulation model. The complex geometry of the study region is not optimal for a structured grid model and so we developed a new method of grid connectivity. This involves a novel approach that allows an unlimited number of individual grids to be combined in an efficient manner to produce a composite grid. We then implemented this new method into the numerical Regional Ocean Modeling System (ROMS) and developed a composite grid of the Hudson River estuary region to investigate the residence time of a passive tracer. Results show that the residence time is a strong function of the time of release (spring vs. neap tide), the along-channel location, and the initial vertical placement. During neap tides there is a maximum in residence time near the bottom of the estuary at the mid-salt intrusion length. During spring tides the residence time is primarily a function of along-channel location and does not exhibit a strong vertical variability. This model study of residence time illustrates the utility of the grid connectivity method for circulation and dispersion studies in regions of complex geometry.W.R. Geyer was supported by the Hudson River Foundation Grant 002/07A,H.G.Arango by the Office of Naval Research,and John Warner was supported by the USGS Community Sediment Modeling Project

    Chandra Observations of the Dwarf Nova WX Hyi in Quiescence

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    We report Chandra observations of the dwarf nova WX Hyi in quiescence. The X-ray spectrum displays strong and narrow emission lines of N, O, Mg, Ne, Si, S and Fe. The various ionization states implied by the lines suggest that the emission is produced within a flow spanning a wide temperature range, from T ~ 10^6 K to T >~ 10^8 K. Line diagnostics indicate that most of the radiation originates from a very dense region, with n ~ 10^{13}-10^{14} cm^{-3}. The Chandra data allow the first tests of specific models proposed in the literature for the X-ray emission in quiescent dwarf novae. We have computed the spectra for a set of models ranging from hot boundary layers, to hot settling flows solutions, to X-ray emitting coronae. WX Hyi differs from other dwarf novae observed at minimum in having much stronger low temperature lines, which prove difficult to fit with existing models, and possibly a very strong, broad O VII line, perhaps produced in a wind moving at a few x 10^3 km/s. The accretion rate inferred from the X-rays is lower than the value inferred from the UV. The presence of high-velocity mass ejection could account for this discrepancy while at the same time explaining the presence of the broad O VII line. If this interpretation is correct, it would provide the first detection of a wind from a dwarf nova in quiescence.Comment: accepted to ApJ; 19 pages, 3 figures, 1 tabl
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