19,967 research outputs found

    Family friendly? The impact on children of the family migration rules: a review of the financial requirements

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    This report, published by the Children's Commissioner, explores the impact on children of the financial requirements of the Immigration Rules (the ‘Rules’), in particular, the minimum income threshold of £18,600 per annum which came into force on 9th July 2012. The Rules govern the admission of spouses and partners from outside the European Economic Area

    Assessment of larval striped bass, Morone saxatilis (Walbaum), stocks in Maryland and Virginia waters. Part II. Assessment of spawning activity in major Virginia rivers. Segment 3. Pt.A. Distribution and abundance of striped bass eggs and larvae in the Rappahannock River during spring, 1982 : final report

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    Segment 1. Distribution and abundance of striped bass eggs and larvae in the upper York River system, Virginia, during spring 1980 Segment 2. Distribution and abundance of striped bass eggs and larvae in the James and Chickahominy Rivers, Virginia, during spring 1981 : draft final report Segment 3. Pt.A. Distribution and abundance of striped bass eggs and larvae in the Rappahannock River during spring, 1982 : final report Segment 3. Pt.B. Dorsal and anal pterygiophore interdigitation patterns in four species of Morone (Teleostei, Percichthyidae) : an aid to larval identification https://doi.org/10.21220/V50X7

    TREX1 is expressed by microglia in normal human brain and increases in regions affected by ischemia

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    BACKGROUND: Mutations in the three-prime repair exonuclease 1 (TREX1) gene have been associated with neurological diseases, including Retinal Vasculopathy with Cerebral Leukoencephalopathy (RVCL). However, the endogenous expression of TREX1 in human brain has not been studied. METHODS: We produced a rabbit polyclonal antibody (pAb) to TREX1 to characterize TREX1 by Western blotting (WB) of cell lysates from normal controls and subjects carrying an RVCL frame-shift mutation. Dual staining was performed to determine cell types expressing TREX1 in human brain tissue. TREX1 distribution in human brain was further evaluated by immunohistochemical analyses of formalin-fixed, paraffin-embedded samples from normal controls and patients with RVCL and ischemic stroke. RESULTS: After validating the specificity of our anti-TREX1 rabbit pAb, WB analysis was utilized to detect the endogenous wild-type and frame-shift mutant of TREX1 in cell lysates. Dual staining in human brain tissues from patients with RVCL and normal controls localized TREX1 to a subset of microglia and macrophages. Quantification of immunohistochemical staining of the cerebral cortex revealed that TREX1 CONCLUSIONS: TREX1 is expressed by a subset of microglia in normal human brain, often in close proximity to the microvasculature, and increases in the setting of ischemic lesions. These findings suggest a role for TREX

    Summary of the 13th IACHEC Meeting

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    We summarize the outcome of the 13th meeting of the International Astronomical Consortium for High Energy Calibration (IACHEC), held at Tenuta dei Ciclamini (Avigliano Umbro, Italy) in April 2018. Fifty-one scientists directly involved in the calibration of operational and future high-energy missions gathered during 3.5 days to discuss the current status of the X-ray payload inter-calibration and possible approaches to improve it. This summary consists of reports from the various working groups with topics ranging from the identification and characterization of standard calibration sources, multi-observatory cross-calibration campaigns, appropriate and new statistical techniques, calibration of instruments and characterization of background, and communication and preservation of knowledge and results for the benefit of the astronomical community.Comment: 12 page

    The Phenomenology of a Top Quark Seesaw Model

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    The top quark seesaw mechanism offers a method for constructing a composite Higgs field without the usual difficulties that accompany traditional technicolor or topcolor theories. The focus of this article is to study the phenomenology of the new physics required by this mechanism. After establishing a set of criteria for a plausible top quark seesaw theory, we develop two models, the first of which has a heavy weak singlet fermion with hypercharge 4/3 while the second has, in addition, a heavy weak singlet hypercharge -2/3 fermion. At low energies, these theories contain one or two Higgs doublets respectively. We then derive the low energy effective Higgs potential in detail for the two-doublet theory as well as study the likely experimental signatures for both theories. A strong constraint on the one-doublet model is the measured value of the rho parameter which permits the new heavy fermion to have a mass of about 5-7 TeV, when the Higgs has a mass greater than 300 GeV. In the two-doublet model, mixing of the new heavy Y=-2/3 fermion and the b quark affects the prediction for R_b. In order to agree with the current limits on R_b, the mass of this fermion should be at least 12 TeV. The mass of the heavy Y=4/3 fermion in the two-doublet model is not as sharply constrained by experiments and can be as light as 2.5 TeV.Comment: 33 pages, 12 figures, uses harvmac and picte

    Kidney cell electrophoresis in space flight: Rationale, methods, results and flow cytometry applications

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    Cultures of human embryonic kidney cells consistently contain an electrophoretically separable subpopulation of cells that produce high levels of urokinase and have an electrophoretic mobility about 85 percent as high as that of the most mobile human embryonic kidney cells. This subpopulation is rich in large epithelioid cells that have relatively little internal structure. When resolution and throughput are adequate, free fluid electrophoresis can be used to isolate a broad band of low mobility cells which also produces high levels of plasminogen activators (PAs). In the course of performing this, it was discovered that all electrophoretic subpopulations of cultured human embryonic kidney cells produce some PAs and that separate subpopulations produce high quantities of different types of PA's. This information and the development of sensitive assays for this project have provided new insights into cell secretion mechanisms related to fibrinolysis. These advances would probably not have been made without the NASA program to explore fundamental questions of free fluid electrophoresis in space

    Short wavelength spectrum and Hamiltonian stability of vortex rings

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    We compare dynamical and energetical stability criteria for vortex rings. It is argued that vortex rings will be intrinsically unstable against perturbations with short wavelengths below a critical wavelength, because the canonical vortex Hamiltonian is unbounded from below for these modes. To explicitly demonstrate this behaviour, we derive the oscillation spectrum of vortex rings in incompressible, inviscid fluids, within a geometrical cutoff procedure for the core. The spectrum develops an anomalous branch of negative group velocity, and approaches the zero of energy for wavelengths which are about six times the core diameter. We show the consequences of this dispersion relation for the thermodynamics of vortex rings in superfluid 4^4He at low temperatures.Comment: 7 pages, 4 figures, final version to appear in Phys. Rev.
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