9,380 research outputs found

    Observations on sandfly fever in Malta and reference to its control by D.D.T.

    Get PDF
    1. Two Sandfly Fever epidemics are reviewed by a Naval Medical Officer whilst working ashore in a temporary barracks under wartime conditions.2. Sandfly Fever is not a dangerous disease, but under such con- ditions as occurred in Malta - in overcrowded dilapidated barracks - it may assume epidemic form which apart from purely medical and health considerations may cause a huge loss in man hours.. It can be most effectively controlled by Dichloro-Diphenyl-Trichlorethane. A method of using this is described. This insecticide used along with other prophylaxtic methods should prevent such epidemics occurring again.4. In comparing reports on Sandfly Fever one finds diversity of opinion on the aetiology of the disease, on its incubation period, on the period of infectivity in the blood, on the incidence amongst 'natives' and one the relative incidence of its clinical manifestations.6. Observations on 600 cases of Sandfly Fever in Yalta are given, from these and from other reports it appears that Sandfly Fever varies in different areas, this makes one wonder whether those differences are due to different types of viruses causing the disease, or to different vectors (is Phlebotcanus Fapatacii the only vector or not).6. An early or even immediate return to duty does not pre-capitate depression or mental distress, as is suggested in most of the relevant literature

    An inversion in the atmosphere of Titan

    Get PDF
    A very detailed greenhouse model derives a methane to hydrogen ratio of unity and a minimum surface pressure of 0.4 atm. Based on a surface gravity g = 140 cm sec/2, the minimum CH4 abundance is 30-40 km-A and the minimum H2 abundance varies from 15 to 85 km-A. A model of the atmosphere of Titan is proposed which seems to be consistent with observations and requires a much smaller CH4 abundance (of the order or 2 km-atm). Although no H2 is required, the presence of some H2 is readily accommodated. In this model, a temperature inversion exists in the atmosphere due to absorption of blue and ultraviolet solar radiation by small particles. The absorbed radiation is re-radiated by the dust and by molecules having long wavelength bands such as CH4 7.7 micrometer and ethane at 12.2 micrometer. The brightness temperature at 20 micrometer is primarily due to re-radiation by the dust

    ν−K0\nu - K^0 Analogy, Dirac-Majorana Neutrino Duality and the Neutrino Oscillations

    Full text link
    The intent of this paper is to convey a new primary physical idea of a Dirac-Majorana neutrino duality in relation to the topical problem of neutrino oscillations. In view of the new atmospheric, solar and the LSND neutrino oscillation data, the Pontecorvo ν−K0\nu - K^0 oscillation analogy is generalized to the notion of neutrino duality with substantially different physical meaning ascribed to the long-baseline and the short-baseline neutrino oscillations. At the level of CP-invariance, the suggestion of dual neutrino properties defines the symmetric two-mixing-angle form of the widely discussed four-neutrino (2+2)(2+2)-mixing scheme, as a result of the lepton charge conservation selection rule and a minimum of two Dirac neutrino fields. With neutrino duality, the two-doublet structure of the Majorana neutrino mass spectrum is a vestige of the two-Dirac-neutrino origin. The fine neutrino mass doublet structure is natural because it is produced by a lepton charge symmetry violating perturbation on a zero-approximation system of two twofold mass-degenerate Dirac neutrino-antineutrino pairs. A set of inferences related to the neutrino oscillation phenomenology in vacuum is considered.Comment: 13 pages, LaTeX. Minor modifications, new references adde

    The luminosity function of Palomar 5 and its tidal tails

    Full text link
    We present the main sequence luminosity function of the tidally disrupted globular cluster Palomar 5 and its tidal tails. For this work we analyzed imaging data obtained with the Wide Field Camera at the INT (La Palma) and data from the Wide Field Imager at the MPG/ESO 2.2 m telescope at La Silla down to a limiting magnitude of approximately 24.5 mag in B. Our results indicate that preferentially fainter stars were removed from the cluster so that the LF of the cluster's main body exhibits a significant degree of flattening compared to other GCs. This is attributed to its advanced dynamical evolution. The LF of the tails is, in turn, enhanced with faint, low-mass stars, which we interpret as a consequence of mass segregation in the cluster.Comment: 4 pages, 3 figures, to be published in the proceedings of the conference "Satellites and tidal streams" held at La Palma, Canary Islands, May 26 - 30, 200

    Stringent constraint on the scalar-neutrino coupling constant from quintessential cosmology

    Get PDF
    An extremely light (mϕ≪10−33eVm_{\phi} \ll 10^{-33} {\rm eV}), slowly-varying scalar field ϕ\phi (quintessence) with a potential energy density as large as 60% of the critical density has been proposed as the origin of the accelerated expansion of the Universe at present. The interaction of this smoothly distributed component with another predominately smooth component, the cosmic neutrino background, is studied. The slow-roll approximation for generic ϕ\phi potentials may then be used to obtain a limit on the scalar-neutrino coupling constant, found to be many orders of magnitude more stringent than the limits set by observations of neutrinos from SN 1987A. In addition, if quintessential theory allows for a violation of the equivalence principle in the sector of neutrinos, the current solar neutrino data can probe such a violation at the 10^{-10} level.Comment: 7 pages, MPLA in press, some parts disregarded and a footnote adde

    Spectroscopy of Giant Stars in the Pyxis Globular Cluster

    Get PDF
    The Pyxis globular cluster is a recently discovered globular cluster that lies in the outer halo (R_{gc} ~ 40 kpc) of the Milky Way. Pyxis lies along one of the proposed orbital planes of the Large Magellanic Cloud (LMC), and it has been proposed to be a detached LMC globular cluster captured by the Milky Way. We present the first measurement of the radial velocity of the Pyxis globular cluster based on spectra of six Pyxis giant stars. The mean heliocentric radial velocity is ~ 36 km/sec, and the corresponding velocity of Pyxis with respect to a stationary observer at the position of the Sun is ~ -191 km/sec. This radial velocity is a large enough fraction of the cluster's expected total space velocity, assuming that it is bound to the Milky Way, that it allows strict limits to be placed on the range of permissible transverse velocities that Pyxis could have in the case that it still shares or nearly shares an orbital pole with the LMC. We can rule out that Pyxis is on a near circular orbit if it is Magellanic debris, but we cannot rule out an eccentric orbit associated with the LMC. We have calculated the range of allowed proper motions for the Pyxis globular cluster that result in the cluster having an orbital pole within 15 degrees of the present orbital pole of the LMC and that are consistent with our measured radial velocity, but verification of the tidal capture hypothesis must await proper motion measurement from the Space Interferometry Mission or HST. A spectroscopic metallicity estimate of [Fe/H] = -1.4 +/- 0.1 is determined for Pyxis from several spectra of its brightest giant; this is consistent with photometric determinations of the cluster metallicity from isochrone fitting.Comment: 22 pages, 5 figures, aaspp4 style, accepted for publication in October, 2000 issue of the PAS

    Wound Repair

    Get PDF
    Following injury, a series of events is initiated that includes global and local reactions. Global reactions, such as inflammatory and immunological responses as well as adjustments in neural and endocrine status, are directed at marshaling the organism\u27s resources for dealing with changes in its integrity and the potential threat of infection or other complications. Injury entails cell and tissue damage and often a physical breach in the barrier against the outside world (e.g., skin). Local reactions are exemplified by immediate hemostatic (e.g., blood clotting) events followed by changes in local cellular composition created by the inflammatory infiltrate and adjustments in resident cell function. These are accompanied by local metabolic adjustments. These events are directed at restoring local integrity and establishing a relevant steady-state. The typical events of wound repair are extensively documented and well characterized. In recent years, research has explored regulation of wound repair at the cellular level and has sought alternative modes for correcting tissue damage that yield more efficient restoration of preinjury conditions (e.g., regeneration). Since repair typically leads to replacement of damaged tissues with connective tissue, reduction in function invariably accompanies wound healing. Where tissue damage is slight, this causes little or no problem for the individual. However, when tissue damage is great, as for example when a finger or limb is lost, the compromise of wound repair carries a noticeable price (both in actual costs and in quality of life for the affected individual)
    • …
    corecore