1,299 research outputs found

    Semiclassical theory of spectral line shapes. II. Applications to CO, HCl, and OCS, broadened by inert gases

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    The semiclassical theory of spectral line broadening developed in the previous paper of this series is used to calculate the half‐widths and shifts of nonoverlapping rotational spectral lines of CO, HCl, and OCS, broadened by inert gases. Comparisons are made with the available experimental data and with related theoretical analyses, and reasonable agreement is obtained. The method used applies both to fairly quantum systems as well as to the relatively classical ones. A symmetrized semiclassical expression for Wigner 6‐j symbols is given and applied

    Space Station/Shuttle Orbiter dynamics during docking

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    Mathematical models of a reference space station configuration (Power Tower) and a Space Shuttle Orbiter are developed and used to study the dynamic behavior of the Space Station/Orbiter system just prior to and subsequent to an impulsive docking of the two spacecraft. The physical model of the space station is a collection of rigid and flexible bodies. The orbiter is modeled as a rigid body. An algorithm developed for use in digitally simulating the dynamics of the system is described and results of its application are presented

    Influence of low and high pressure baroreceptors on plasma renin activity in humans

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    The effects of low and high pressure baroreceptors on plasma renin activity (immunoassay) were evaluated using graded lower body suction (LBS) in six healthy men. LBS at -10 and -20 mmHg for 10 min decreased central venous pressure without changing arterial pressure and thereby presumably reduced low but not high pressure baroreceptor inhibition of renin release. LBS at these levels produced forearm vasoconstriction, but did not increase renin. LBS at -40 mmHG decreased central venous and arterial pulse pressure and thus reduced both low and high pressure baroreceptor inhibition. LBS at this level produced forearm vasoconstriction and tachycardia and increased renin. In summary, reduction in low pressure baroreceptor inhibition in humans did not increase renin in the presence of physiological tonic inhibition from high pressure baroreceptors. Increases in renin did not occur until there was combined reduction of high and low pressure baroreceptor inhibition on plasma renin activity

    The role of atrial natriuretic peptide to attenuate inflammation in a mouse skin wound and individually perfused rat mesenteric microvessels.

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    We tested the hypothesis that the anti-inflammatory actions of atrial natriuretic peptide (ANP) result from the modulation of leukocyte adhesion to inflamed endothelium and not solely ANP ligation of endothelial receptors to stabilize endothelial barrier function. We measured vascular permeability to albumin and accumulation of fluorescent neutrophils in a full-thickness skin wound on the flank of LysM-EGFP mice 24 h after formation. Vascular permeability in individually perfused rat mesenteric microvessels was also measured after leukocytes were washed out of the vessel lumen. Thrombin increased albumin permeability and increased the accumulation of neutrophils. The thrombin-induced inflammatory responses were attenuated by pretreating the wound with ANP (30 min). During pretreatment ANP did not lower permeability, but transiently increased baseline albumin permeability concomitant with the reduction in neutrophil accumulation. ANP did not attenuate acute increases in permeability to histamine and bradykinin in individually perfused rat microvessels. The hypothesis that anti-inflammatory actions of ANP depend solely on endothelial responses that stabilize the endothelial barrier is not supported by our results in either individually perfused microvessels in the absence of circulating leukocytes or the more chronic skin wound model. Our results conform to the alternate hypothesis that ANP modulates the interaction of leukocytes with the inflamed microvascular wall of the 24 h wound. Taken together with our previous observations that ANP reduces deformability of neutrophils and their strength of attachment, rolling, and transvascular migration, these observations provide the basis for additional investigations of ANP as an anti-inflammatory agent to modulate leukocyte-endothelial cell interactions

    Dynamische Lichtstreuung zur Partikelgrößenbestimmung von CuZn-Hydroxykarbonaten

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    EÇA, MACHADO, AND WORLD LITERATURE

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    This essay discusses Machado and Eça in the context of “World Literature,” the advent of which is of great importance for the promotion of Luso-Brazilian writers on the global stage. It emphasizes that Luso-Brazilianists have many outstanding writers to offer this new approach to Goethe’s old idea of Weltliteratur. This study argues that, by working with Portuguese language texts, scholars of Portuguese and Brazilian literature must work harder and more strategically than most to gain for these writers the exposure and international respect that they deserve. This essay highlights prominent Portuguese and Brazilian literary figures and their role on the global stage. Issues of translation will now become more critical than ever, as will how skillfully we wield the comparative method in our critical commentaries and the venues in which we aim to publish our work
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