2,259 research outputs found

    Penetrating injuries in dogs and cats: a study of 16 cases

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    The objective of this retrospective study was to assess radiographical and surgical findings, surgical management and outcome of penetrating injuries in dogs and cats by evaluating patient records. Sixteen patients were identified (15 dogs and one cat), four with gunshot wounds, and 12 with fight wounds (11 with bite wounds, one struck by a claw). The thoracic cavity was affected in six patients, the abdominal cavity in three cases. Both cavities were affected in five dogs and the trachea in two cases. All of the patients with fight wounds were small breed dogs. Multiple injuries to internal organs that required intervention were found surgically after gunshot wounds and a high amount of soft tissue trauma requiring reconstruction was present after fight wounds. Radiography diagnosed body wall disruption in two cases. All of the affected thoracic body walls in the fight group had intercostal muscle disruptions which was diagnosed surgically. Fourteen patients survived until discharge and had a good outcome. In conclusion, penetrating injuries should be explored as they are usually accompanied by severe damage to either the internal organs or to the body wall. A high level of awareness is required to properly determine the degree of trauma of intercostal muscle disruption in thoracic fight wounds

    A multi-flow model for microquasars

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    We present a new picture for the central regions of Black Hole X-ray Binaries. In our view, these central regions have a multi-flow configuration which consists in (1) an outer standard accretion disc down to a transition radius r_J, (2) an inner magnetized accretion disc below r_J driving (3) a non relativistic self-collimated electron-proton jet surrounding, when adequate conditions for pair creation are met, (4) a ultra relativistic electron-positron beam. This accretion-ejection paradigm provides a simple explanation to the canonical spectral states, from radio to X/gamma-rays, by varying the transition radius r_J and disc accretion rate independently. Large values of r_J and low accretion rate correspond to Quiescent and Hard states. These states are characterized by the presence of a steady electron-proton MHD jet emitted by the disc below r_J. The hard X-ray component is expect to form at the jet basis. When r_J becomes smaller than the marginally stable orbit r_i, the whole disc resembles a standard accretion disc with no jet, characteristic of the Soft state. Intermediate states correspond to situations where r_J ~ r_i. At large accretion rate, an unsteady pair cascade process is triggered within the jet axis, giving birth to flares and ejection of relativistic pair blobs. This would correspond to the luminous intermediate state, with its associated superluminal motions.Comment: 12 pages, 3 figures. Proceedings of ``High Energies in the Highlands'', Fort-William, 27 June-1 July 200

    The Role of Knowledge Externalities in the Spatial Distribution of Economic Growth: A Spatial Econometric Analysis for US Counties, 19692003

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    The traditional view of cities as monocentric conglomerates of people clustered around an employment center, driving economic growth in cities that subsequently trickles down to the hinterland, is increasingly being challenged. In particular, the role of space, technological leadership, human capital, increasing returns to scale and industrial clustering as well as hierarchical organization principles have been emphasized in the more recent literature. This paper utilizes exploratory and spatial econometric data analysis techniques to investigate these issues for US counties using data from 1969 through 2003. Ultimately, contiguous and hierarchical organization and interaction patterns are captured using an endogenous growth model allowing for spatial effects, inspired by earlier work on human capital and technology gaps. We investigate a neoclassical growth model and compare it to a spatial version of an endogenous growth model allowing for "domestic" investment in human capital and catch-up to the technology leader, and find that human capital strongly contributes to growth in a neoclassical setting, but much less so in an endogenous setting. In the endogenous model the catch-up term dominates in comparison to "domestic" human capital effects.Labor and Human Capital,

    Growth and Technological Leadership in US Industries: A Spatial Econometric Analysis at the State Level, 1963-1997

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    For several decades, cross-country analyses have dominated the literature on economic growth. Recently, these analyses have been extended to include sectoral variation as well as spatial variation across sub-national regions. This paper investigates economic growth and potential determinants of the process of catch-up to technology leaders for several economic sectors, using data for the lower 48 US states from 1963 through 1997. We analyze the potential influence of factors such as human capital, and geographical distance to the technology leader. A spatially explicit growth model in which technological progress is endogenously determined is used to model productivity growth in nine US industries, ranging from mining to government, and including a combined sector of totals. The results indicate that none of the sectors exhibits ó-convergence, but they all show strong evidence of â-convergence with a convergence club pattern that is apparent for the wholesale/retail sector. The catch-up effect to the technology leader dominates the growth process in almost all sectors, and it works through the interaction with human capital.regional economic growth, convergence, industry level, technological leadership, spatial econometrics, Industrial Organization, C21, I23, O33, R12,

    The influence of the jet opening angle on the appearance of relativistic jets

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    We reinvestigate the problem of the appearance of relativistic jets when geometrical opening is taken into account. We propose a new criterion to define apparent velocities and Doppler factors, which we think being determined by the brightest zone of the jet. We numerically compute the apparent velocity and the Doppler factor of a non homokinetic jet using different velocity profiles. We argue that if the motion is relativistic, the high superluminal velocities beta_{app} ~ gamma, expected in the case of an homokinetic jet, are only possible for geometrical collimation smaller than the relativistic beaming angle 1/gamma. This is relatively independent of the jet velocity profile. For jet collimation angles larger than 1/gamma, the apparent image of the jet will always be dominated by parts of the jet traveling directly towards the observer at lorentz factors < gamma resulting in maximal apparent velocities smaller than gamma}. Furthermore, getting rid of the homokinetic hypothesis yields a complex relation between the observing angle and the Doppler factor, resulting in important consequences for the numerical computation of AGN population and unification scheme model.Comment: Accepted in MNRAS, 12 pages and 9 Figure
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