467 research outputs found

    STABILITY OF POLYNOMIALS UNDER CORRELATED COEFFICIENT PERTURBATIONS.

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    The robust stability of polynomials with respect to real parameter variations is investigated. The coefficients of the polynomial are assumed to be linear functions of several real parameters. An algorithm to calculate the maximum allowable variations of the parameters so the roots still remain in prescribed regions of the complex plane is presented. Examples are given to illustrate the method

    A Combined Digital-Analog Tracker for Terrestrial Applications

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    A combined Digital-Analog Tracker is suggested to allow maximum efficiency in a solar-electrical energy converter, utilizing a twelve-foot parabolic collector. The analog tracker compares solar beam radiation to ambient (diffuse) light to obtain optimum placement of the collector when the sun is visible. The digital portion of the tracker utilizes a wired program which derives information on solar position from a non-volatile random-access semiconductor memory. This arrangement allows accurate mapping of the sun even when the sun is obscured by atmospheric phenomena which would make mapping impossible

    System Modeling and Control of Smart Structures

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    This paper presents multidisciplinary research and curriculum efforts at the University of Missouri-Rolla in the smart structures area. The primary objective of our project is to integrate research results with curriculum development for the benefit of students in electrical, and mechanical and aerospace engineering and engineering mechanics. The approach to the accomplishment of curriculum objectives is the development of a two-course sequence in the smart structures area with an integrated laboratory. The research portion of the project addresses structural identification and robust control methods for smart structures. A brief summary of the research results and a description of curriculum development in the smart structures area are described in this pape

    Soluble α2-macroglobulin receptor is increased in endotracheal aspirates from infants and children after cardiopulmonary bypass

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    ObjectiveCytokine dysregulation contributes to the systemic inflammatory response after cardiopulmonary bypass. Clearance of cytokine binding proteins may be important in the resolution of inflammation. Our aim was to determine whether the cytokine binding protein α2-macroglobulin and its soluble receptor were upregulated in endotracheal aspirates from infants and children undergoing cardiopulmonary bypass.MethodsSeventy tracheal aspirates were collected before and after cardiopulmonary bypass from 35 infants and children undergoing surgical correction of congenital heart defects. α2-Macroglobulin and the soluble α2-macroglobulin receptor were identified by Western blot. With the use of multi-analyte cytokine profiling, pro-inflammatory and anti-inflammatory cytokines were quantified, normalized to total protein, and expressed as ratios. Paired t tests and Wilcoxon signed-rank tests were performed between prebypass and postbypass samples. Correlations were examined among α2-macroglobulin, soluble α2-macroglobulin receptor, cytokine ratios, and the clinical variables of cardiopulmonary bypass, aortic crossclamp, and circulatory arrest times.Resultsα2-Macroglobulin increased by 50% (mean densitometry increase 82,683 ± 184,594, P = .012), and soluble α2-macroglobulin receptor increased by 17% (mean densitometry increase 506,148 ± 687,037, P = .0001) after cardiopulmonary bypass. The ratio of interleukin-8/interleukin-4 increased by 136% (P = .0001), and interleukin-8/interleukin-10 increased by 102% (P = .001). The increase in soluble α2-macroglobulin receptor was positively correlated with the ratios of interleukin-8/interleukin-4 and interleukin-8/interleukin-10. There were no statistically significant positive correlations between the increase in α2-macroglobulin or soluble α2-macroglobulin receptor and measured clinical variables.ConclusionsWe report for the first time the upregulation of α2-macroglobulin and soluble α2-macroglobulin receptor in tracheal aspirates after cardiopulmonary bypass in infants and children. Soluble α2-macroglobulin receptor correlates with increased α2-macroglobulin and a disproportionate increase in pro-inflammatory to anti-inflammatory cytokine ratios

    Impact of Sleep and Circadian Disruption on Energy Balance and Diabetes: A Summary of Workshop Discussions

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    A workshop was held at the National Institute for Diabetes and Digestive and Kidney Diseases with a focus on the impact of sleep and circadian disruption on energy balance and diabetes. The workshop identified a number of key principles for research in this area and a number of specific opportunities. Studies in this area would be facilitated by active collaboration between investigators in sleep/circadian research and investigators in metabolism/diabetes. There is a need to translate the elegant findings from basic research into improving the metabolic health of the American public. There is also a need for investigators studying the impact of sleep/circadian disruption in humans to move beyond measurements of insulin and glucose and conduct more in-depth phenotyping. There is also a need for the assessments of sleep and circadian rhythms as well as assessments for sleep-disordered breathing to be incorporated into all ongoing cohort studies related to diabetes risk. Studies in humans need to complement the elegant short-term laboratory-based human studies of simulated short sleep and shift work etc. with studies in subjects in the general population with these disorders. It is conceivable that chronic adaptations occur, and if so, the mechanisms by which they occur needs to be identified and understood. Particular areas of opportunity that are ready for translation are studies to address whether CPAP treatment of patients with pre-diabetes and obstructive sleep apnea (OSA) prevents or delays the onset of diabetes and whether temporal restricted feeding has the same impact on obesity rates in humans as it does in mice

    Report of the Committee on Resolutions- Declaration

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    Pamphlet concerning a declaration made by the National Educational Association at the forty-fourth annual convention

    Non-universal equilibrium crystal shape results from sticky steps

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    The anisotropic surface free energy, Andreev surface free energy, and equilibrium crystal shape (ECS) z=z(x,y) are calculated numerically using a transfer matrix approach with the density matrix renormalization group (DMRG) method. The adopted surface model is a restricted solid-on-solid (RSOS) model with "sticky" steps, i.e., steps with a point-contact type attraction between them (p-RSOS model). By analyzing the results, we obtain a first-order shape transition on the ECS profile around the (111) facet; and on the curved surface near the (001) facet edge, we obtain shape exponents having values different from those of the universal Gruber-Mullins-Pokrovsky-Talapov (GMPT) class. In order to elucidate the origin of the non-universal shape exponents, we calculate the slope dependence of the mean step height of "step droplets" (bound states of steps) using the Monte Carlo method, where p=(dz/dx, dz/dy)$, and represents the thermal averag |p| dependence of , we derive a |p|-expanded expression for the non-universal surface free energy f_{eff}(p), which contains quadratic terms with respect to |p|. The first-order shape transition and the non-universal shape exponents obtained by the DMRG calculations are reproduced thermodynamically from the non-universal surface free energy f_{eff}(p).Comment: 31 pages, 21 figure

    Ego-Splitting and the Transcendental Subject. Kant’s Original Insight and Husserl’s Reappraisal

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    In this paper, I contend that there are at least two essential traits that commonly define being an I: self-identity and self-consciousness. I argue that they bear quite an odd relation to each other in the sense that self-consciousness seems to jeopardize self-identity. My main concern is to elucidate this issue within the range of the transcendental philosophies of Immanuel Kant and Edmund Husserl. In the first section, I shall briefly consider Kant’s own rendition of the problem of the Egosplitting. My reading of the Kantian texts reveals that Kant himself was aware of this phenomenon but eventually deems it an unexplainable fact. The second part of the paper tackles the same problematic from the standpoint of Husserlian phenomenology. What Husserl’s extensive analyses on this topic bring to light is that the phenomenon of the Ego-splitting constitutes the bedrock not only of his thought but also of every philosophy that works within the framework of transcendental thinking

    Coherent Stranski-Krastanov growth in 1+1 dimensions with anharmonic interactions: An equilibrium study

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    The formation of coherently strained three-dimensional islands on top of the wetting layer in Stranski-Krastanov mode of growth is considered in a model in 1+1 dimensions accounting for the anharmonicity and non-convexity of the real interatomic forces. It is shown that coherent 3D islands can be expected to form in compressed rather than in expanded overlayers beyond a critical lattice misfit. In the latter case the classical Stranski-Krastanov growth is expected to occur because the misfit dislocations can become energetically favored at smaller island sizes. The thermodynamic reason for coherent 3D islanding is the incomplete wetting owing to the weaker adhesion of the edge atoms. Monolayer height islands with a critical size appear as necessary precursors of the 3D islands. The latter explains the experimentally observed narrow size distribution of the 3D islands. The 2D-3D transformation takes place by consecutive rearrangements of mono- to bilayer, bi- to trilayer islands, etc., after exceeding the corresponding critical sizes. The rearrangements are initiated by nucleation events each next one requiring to overcome a lower energetic barrier. The model is in good qualitative agreement with available experimental observations.Comment: 12 pages text, 15 figures, Accepted in Phys.Rev.B, Vol.61, No2
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