184 research outputs found

    The Consequence of Land Mines on Public Health

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    An estimated 110 million land mines scattered in 64 countries continue to terrorize people and destroy human lives long after wars and fighting have ceased. Despite efforts to clear these devices, their numbers continue to increase and their presence, constitutes a substantial threat to public health in the affected countries. Direct consequences include both the physical and emotional injuries from the impact, flying debris, and structural collapse associated with their detonation. Indirect consequences include increases in the incidence of waterborne diseases, diarrhea, malnutrition, infectious diseases, and spread of the human immunodeficiency virus associated with the increased use of blood. Those at highest risk of these latter consequences are mostly the disadvantaged poor, especially children. Psychiatric disorders, such as post-traumatic stress disorder, occur in those not directly injured as well as those physically wounded by the explosion. Besides efforts to ban production, stockpiling and export of land mines, a comprehensive and integrated health program aimed at the prevention, treatment, and rehabilitation of those injured directly or indirectly by land mines is needed urgently. Strategies should include mine-awareness programs, enhanced transport of those directly injured, training the villagers in first aid, augmenting the capacity and quality of treatment facilities, improving the psychological support and treatment capabilities, development of rehabilitation programs, and the institution and enhancement of public-health programs directed at the indirect consequences associated with the presence of land mines. Land mines constitute a major public-health problem in the world that must be addresse

    WIMP Annual Modulation with Opposite Phase in Late-Infall Halo Models

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    We show that in the late-infall model of our galactic halo by P. Sikivie the expected phase of the annual modulation of a WIMP halo signal in direct detection experiments is opposite to the one usually expected. If a non-virialized halo component due to the infall of (collisionless) dark matter particles cannot be rejected, an annual modulation in a dark matter signal should be looked for by experimenters without fixing the phase a-priori. Moreover, WIMP streams coming to Earth from directions above and below the galactic plane should be expected, with a characteristic pattern of arrival directions.Comment: 15 pages, 5 figure

    A value hierarchy for inclusive design of heart valve implants in regenerative medicine

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    Aim: This paper investigates the conditions for inclusive design of regenerative medicine interventions from a bioethical perspective, taking regenerative valve implants as a showcase. Methods: A value hierarchy is construed to translate the value of justice into norms and design requirements for inclusive design of regenerative valve implants. Results: Three norms are proposed and translated into design requirements: regenerative valve implants should be designed to promote equal opportunity to good health for all potential users; equal respect for all potential users should be shown; and the implants should be designed to be accessible to everyone in need. Conclusion: The norms and design requirements help to design regenerative valve implants that are appropriate, respectful and available for everyone in need.</p

    In situ measurements of near-surface hydraulic conductivity in engineered clay slopes

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    In situ measurements of near-saturated hydraulic conductivity in fine grained soils have been made at six exemplar UK transport earthwork sites: three embankment and three cutting slopes. This paper reports 143 individual measurements and considers the factors that influence the spatial and temporal variability obtained. The test methods employed produce near-saturated conditions and flow under constant head. Full saturation is probably not achieved due to preferential and by-pass flow occurring in these desiccated soils. For an embankment, hydraulic conductivity was found to vary by five orders of magnitude in the slope near-surface (0 to 0.3 metres depth), decreasing by four orders of magnitude between 0.3 and 1.2 metres depth. This extremely high variability is in part due to seasonal temporal changes controlled by soil moisture content, which can account for up to 1.5 orders of magnitude of this variability. Measurements of hydraulic conductivity at a cutting also indicated a four orders of magnitude range of hydraulic conductivity for the near-surface, with strong depth dependency of a two orders of magnitude decrease from 0.2 to 0.6 metres depth. The main factor controlling the large range is found to be spatial variability in the soil macro structure generated by wetting/drying cycle driven desiccation and roots. The measurements of hydraulic conductivity reported in this paper were undertaken to inform and provide a benchmark for the hydraulic parameters used in numerical models of groundwater flow. This is an influential parameter in simulations incorporating the combined weather/vegetation/infiltration/soil interaction mechanisms that are required to assess the performance and deterioration of earthwork slopes in a changing climate

    Validation of a novel numerical model to predict regionalized blood flow in the coronary arteries

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    Aims: Ischaemic heart disease results from insufficient coronary blood flow. Direct measurement of absolute flow (mL/min) is feasible, but has not entered routine clinical practice in most catheterization laboratories. Interventional cardiologists, therefore, rely on surrogate markers of flow. Recently, we described a computational fluid dynamics (CFD) method for predicting flow that differentiates inlet, side branch, and outlet flows during angiography. In the current study, we evaluate a new method that regionalizes flow along the length of the artery. Methods and results: Three-dimensional coronary anatomy was reconstructed from angiograms from 20 patients with chronic coronary syndrome. All flows were computed using CFD by applying the pressure gradient to the reconstructed geometry. Side branch flow was modelled as a porous wall boundary. Side branch flow magnitude was based on morphometric scaling laws with two models: a homogeneous model with flow loss along the entire arterial length; and a regionalized model with flow proportional to local taper. Flow results were validated against invasive measurements of flow by continuous infusion thermodilution (Coroventis™, Abbott). Both methods quantified flow relative to the invasive measures: homogeneous (r 0.47, P 0.006; zero bias; 95% CI -168 to +168 mL/min); regionalized method (r 0.43, P 0.013; zero bias; 95% CI -175 to +175 mL/min). Conclusion: During angiography and pressure wire assessment, coronary flow can now be regionalized and differentiated at the inlet, outlet, and side branches. The effect of epicardial disease on agreement suggests the model may be best targeted at cases with a stenosis close to side branches.</p

    Are the magnetic fields of millisecond pulsars ~ 10^8 G?

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    It is generally assumed that the magnetic fields of millisecond pulsars (MSPs) are 108\sim 10^{8}G. We argue that this may not be true and the fields may be appreciably greater. We present six evidences for this: (1) The 108\sim 10^{8} G field estimate is based on magnetic dipole emission losses which is shown to be questionable; (2) The MSPs in low mass X-ray binaries (LMXBs) are claimed to have <1011< 10^{11} G on the basis of a Rayleygh-Taylor instability accretion argument. We show that the accretion argument is questionable and the upper limit 101110^{11} G may be much higher; (3) Low magnetic field neutron stars have difficulty being produced in LMXBs; (4) MSPs may still be accreting indicating a much higher magnetic field; (5) The data that predict 108\sim 10^{8} G for MSPs also predict ages on the order of, and greater than, ten billion years, which is much greater than normal pulsars. If the predicted ages are wrong, most likely the predicted 108\sim 10^{8} G fields of MSPs are wrong; (6) When magnetic fields are measured directly with cyclotron lines in X-ray binaries, fields 108\gg 10^{8} G are indicated. Other scenarios should be investigated. One such scenario is the following. Over 85% of MSPs are confirmed members of a binary. It is possible that all MSPs are in large separation binaries having magnetic fields >108> 10^{8} G with their magnetic dipole emission being balanced by low level accretion from their companions.Comment: 16 pages, accept for publication in Astrophysics and Space Scienc

    The evolution of galaxy groups and of galaxies therein

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    Properties of groups of galaxies depend sensitively on the algorithm for group selection, and even the most recent catalogs of groups built from redshift-space selection should suffer from projections and infalling galaxies. The cosmo-dynamical evolution of groups from initial Hubble expansion to collapse and virialization leads to a fundamental track (FT) in virial-theorem-M/L vs crossing time. The increased rates of mergers, both direct and after dynamical friction, in groups relative to clusters, explain the higher fraction of elliptical galaxies at given local number density in X-ray selected groups, relative to clusters, even when the hierarchical evolution of groups is considered. Galaxies falling into groups and clusters should later travel outwards to typically 2 virial radii, which is somewhat less than the outermost radius where observed galaxy star formation efficiencies are enhanced relative to field galaxies of same morphological type. An ongoing analysis of the internal kinematics of X-ray selected groups suggests that the radial profiles of line of sight velocity dispersion are consistent with isotropic NFW distributions for the total mass density, with higher (lower) concentrations than LambdaCDM predictions in groups of high (low) mass. The critical mass, at M200 ~ 10^13 M_sun is consistent with possible breaks in the X-ray luminosity-temperature and Fundamental Plane relations. The internal kinematics of groups indicate that the M-T relation of groups should agree with that extrapolated from clusters with no break at the group scale. The analyses of observed velocity dispersion profiles and of the FT both suggest that low velocity dispersion groups (compact and loose, X-ray emitting or undetected) are quite contaminated by chance projections.Comment: Invited review, ESO workshop "Groups of Galaxies in the Nearby Universe", held in Santiago, Chile, 5-9 December 2005, ed. I. Saviane, V. Ivanov & J. Borissova, 16 page

    Subaru Studies of the Cosmic Dawn

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    An overview on the current status of the census of the early universe population is given. Observational surveys of high redshift objects provide direct opportunities to study the early epoch of the Universe. The target population included are Lyman Alpha Emitters (LAE), Lyman Break Galaxies (LBG), gravitationally lensed galaxies, quasars and gamma-ray bursts (GRB). The basic properties of these objects and the methods used to study them are reviewed. The present paper highlights the fact that the Subaru Telescope group made significant contributions in this field of science to elucidate the epoch of the cosmic dawn and to improve the understanding of how and when infant galaxies evolve into mature ones.Comment: 14 pages, 11 figures, accepted for publication in the Proceedings of the Japan Academy, Series

    Cosmology with clusters of galaxies

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    In this Chapter I review the role that galaxy clusters play as tools to constrain cosmological parameters. I will concentrate mostly on the application of the mass function of galaxy clusters, while other methods, such as that based on the baryon fraction, are covered by other Chapters of the book. Since most of the cosmological applications of galaxy clusters rely on precise measurements of their masses, a substantial part of my Lectures concentrates on the different methods that have been applied so far to weight galaxy clusters. I provide in Section 2 a short introduction to the basics of cosmic structure formation. In Section 3 I describe the Press--Schechter (PS) formalism to derive the cosmological mass function, then discussing extensions of the PS approach and the most recent calibrations from N--body simulations. In Section 4 I review the methods to build samples of galaxy clusters at different wavelengths. Section 5 is devoted to the discussion of different methods to derive cluster masses. In Section 6 I describe the cosmological constraints, which have been obtained so far by tracing the cluster mass function with a variety of methods. Finally, I describe in Section 7 the future perspectives for cosmology with galaxy clusters and the challenges for clusters to keep playing an important role in the era of precision cosmology.Comment: 49 pages, 19 figures, Lectures for 2005 Guillermo Haro Summer School on Clusters, to appear in "Lecture notes in Physics" (Springer
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