4,852 research outputs found

    Diterpene modulator of macrophage phagosomal maturation

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    Novel uses for diterpene modulators of macrophage phagosomal maturation are provided. The diterpene isotuberculosinol is used as an immune modulator, assay for pharmaceutical compositions and an isolated Mycobacterium tuberculosis labdane-related diterpenoid virulence factor. A method of treating Mycobacterium tuberculosis infectivity is further provided

    Final design report of a personnel launch system and a family of heavy lift launch vehicles

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    The objective was to design both a Personnel Launch System (PLS) and a family of Heavy Lift Launch Vehicles (FHLLVs) that provide low cost and efficient operation in missions not suited for the Shuttle. The PLS vehicle is designed primarily for space station crew rotation and emergency crew return. The final design of the PLS vehicle and its interior is given. The mission of the FHLLVs is to place large, massive payloads into Earth orbit with payload flexibility being considered foremost in the design. The final design of three launch vehicles was found to yield a payload capacity range from 20 to 200 mt. These designs include the use of multistaged, high thrust liquid engines mounted on the core stages of the rocket

    TeV scale resonant leptogenesis from supersymmetry breaking

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    We propose a model of TeV-scale resonant leptogenesis based upon recent models of the generation of light neutrino masses from supersymmetry-breaking effects with TeV-scale right-handed (rhd) neutrinos, NiN_i. The model leads to naturally large cosmological lepton asymmetries via the resonant behaviour of the one-loop self-energy contribution to NiN_i decay. Our model addresses the primary problems of previous phenomenological studies of low-energy leptogenesis: a rational for TeV-scale rhd neutrinos with small Yukawa couplings so that the out-of equilibrium condition for NiN_i decay is satisfied; the origin of the tiny, but non-zero mass splitting required between at least two NiN_i masses; and the necessary non-trivial breaking of flavour symmetries in the rhd neutrino sector. The low mass-scale of the rhd neutrinos and their superpartners, and the TeV-scale AA-terms automatically contained within the model offer opportunities for partial direct experimental tests of this leptogenesis mechanism at future colliders.Comment: 10 Pages latex, version for JHE

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    The impact of targeting all elderly persons in England and Wales for yearly influenza vaccination: excess mortality due to pneumonia or influenza and time trend study.

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    OBJECTIVE: To investigate the impact on mortality due to pneumonia or influenza of the change from risk-based to age group-based targeting of the elderly for yearly influenza vaccination in England and Wales. DESIGN: Excess mortality estimated using time series of deaths registered to pneumonia or influenza, accounting for seasonality, trend and artefacts. Non-excess mortality plotted as proxy for long-term trend in mortality. SETTING: England and Wales. PARTICIPANTS: Persons aged 65-74 and 75+ years whose deaths were registered to underlying pneumonia or influenza between 1975/1976 and 2004/2005. OUTCOME MEASURES: Multiplicative effect on average excess pneumonia and influenza deaths each winter in the 4-6 winters since age group-based targeting of vaccination was introduced (in persons aged 75+ years from 1998/1999; in persons aged 65+ years from 2000/2001), estimated using multivariable regression adjusted for temperature, antigenic drift and vaccine mismatch, and stratified by dominant circulating influenza subtype. Trend in baseline weekly pneumonia and influenza death rates. RESULTS: There is a suggestion of lower average excess mortality in the six winters after age group-based targeting began compared to before, but the CI for the 65-74 years age group includes no difference. Trend in baseline pneumonia and influenza mortality shows an apparent downward turning point around 2000 for the 65-74 years age group and from the mid-1990s in the 75+ years age group. CONCLUSIONS: There is weakly supportive evidence that the marked increases in vaccine coverage accompanying the switch from risk-based to age group-based targeting of the elderly for yearly influenza vaccination in England and Wales were associated with lower levels of pneumonia and influenza mortality in older people in the first 6 years after age group-based targeting began. The possible impact of these policy changes is observed as weak evidence for lower average excess mortality as well as a turning point in baseline mortality coincident with the changes

    Mass loading of the solar wind by a sungrazing comet

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    Collisionless mass loading was suggested by Biermann et al. (1967) for describing interactions between the solar wind and cometary atmospheres. Recent observations have led to an increased interest in coronal mass loading due to sungrazing comets and collisional debris of sunward migrating interplanetary dust particles. In a previous paper, we presented a 3‐D MHD model of the solar corona based on the Block‐Adaptive‐Tree‐Solarwind‐Roe‐Upwind‐Scheme code which includes the interaction of dust with the solar wind. We have shown the impact on the solar wind from abrupt mass loading in the coronal region. We apply the model to a sungrazing cometary source, using ejected dust dynamics to generate tail‐shaped mass‐loading regions. Results help predict the effects on the solar wind acceleration and composition due to sungrazing comets, such as Comet C/2011 W3 (Lovejoy). We show how these effects may be detected by the upcoming Solar Probe Plus Mission. Key Points Application of mass loading in the SWMF SC component for sungrazing comets Extension to a tail source model for mass loading due to a sungrazing comet Prediction of mass‐loaded solar wind parameters along a space probe pathPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108676/1/grl51967.pd

    A cluster version of the GGT sum rule

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    We discuss the derivation of a ``cluster sum rule'' from the Gellmann-Goldberger-Thirring (GGT) sum rule as an alternative to the Thomas-Reiche-Kuhn (TRK) sum rule, which was used as the basis up to now. We compare differences in the assumptions and approximations. Some applications of the sum rule for halo nuclei, as well as, nuclei with a pronounced cluster structure are discussed.Comment: 14 pages, to be published in Nucl. Phys.

    Remote sensing the plasmasphere, plasmapause, plumes and other features using ground-based magnetometers

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    The plasmapause is a highly dynamic boundary between different magnetospheric particle populations and convection regimes. Some of the most important space weather processes involve wave-particle interactions in this region, but wave properties may also be used to remote sense the plasmasphere and plasmapause, contributing to plasmasphere models. This paper discusses the use of existing ground magnetometer arrays for such remote sensing. Using case studies we illustrate measurement of plasmapause location, shape and movement during storms; refilling of flux tubes within and outside the plasmasphere; storm-time increase in heavy ion concentration near the plasmapause; and detection and mapping of density irregularities near the plasmapause, including drainage plumes, biteouts and bulges. We also use a 2D MHD model of wave propagation through the magnetosphere, incorporating a realistic ionosphere boundary and Alfvén speed profile, to simulate ground array observations of power and cross-phase spectra, hence confirming the signatures of plumes and other density structures
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