420 research outputs found

    Effects of edge disorder in nano-scale antiferromagnetic clusters

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    We study the distribution of local magnetic susceptibilities in the two-dimensional antiferromagnetic S=1/2 Heisenberg model on various random clusters, in order to determine whether effects of edge disorder could be detected in NMR experiments (through the line shape, as given by the distribution of local Knight shifts). Although the effects depend strongly on the nature of the edge and the cluster size, our results indicate that line widths broader than the average shift should be expected even in clusters as large as ≈1000\approx 1000 lattice spacing in diameter. Experimental investigations of the NMR line width should give insights into the magnetic structure of the edges.Comment: 4 pages, 4 figure

    The Validity, Reliability, Measurement Error, and Minimum Detectable Change of the 30‐Second Fast‐Paced Walk Test in Persons with Knee Osteoarthritis: A Novel Test of Short‐Distance Walking Ability

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    Objective To develop and establish the reliability, validity, measurement error, and minimum detectable change of a novel 30‐second fast‐paced walk test (30SFW) in persons with knee osteoarthritis (OA) that is easy to administer and can quantify walking performance in persons of all abilities. Methods Twenty females with symptomatic knee OA (mean age [SD] 58.30 [8.05] years) and 20 age‐ and sex‐matched asymptomatic controls (57.25 [8.71] years) participated in the study. Participants completed questionnaires of demographic and clinical data, the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the 36‐item Short Form Health Survey (SF‐36) followed by 30SFW performance. Participants returned 2‐7 days later and performed the 30SFW again. Results The knee OA group reported function that was worse than controls (all KOOS subscales; P \u3c 0.0001). The 30SFW intrarater and interrater reliability were excellent [ICC(2,1) = 0.95‐0.99]. Knee OA participants walked a shorter distance in the 30SFW than controls (mean [SD]: OA 44.4 m [9.5 m]; control 58.1 m [7.8 m]; P \u3c 0.0001). Positive strong correlations were found between the 30SFW and the KOOS–Activity of Daily Living, SF‐36‐Physical Functioning, and SF‐36‐Physical Health Composite scores (P \u3c 0.0001). A nonsignificant, weak correlation between 30SFW and SF‐36‐Mental Health scores was present (r = 0.32, P = 0.05). Conclusion The 30SFW has excellent intrarater and interrater reliability. The 30SFW demonstrated excellent known groups, convergent, and discriminant validity as a measure of short‐distance walking ability in persons with knee OA. Clinicians and researchers should consider using the 30SFW to quantify walking ability in persons with knee OA and assess walking ability change

    Analysis of the project fire re-entry package flow field final technical report

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    Theoretical prediction of state of gas in flow field surrounding Apollo type vehicle in reentry at hypersonic speed

    DENSITÉ DES NIVEAUX DE BASSE ÉNERGIE ET INSTABILITÉS DE SURFACE DANS LES NOYAUX LOURDS DE TRANSITION

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    Une analyse statistique des niveaux nucléaires de Au, Pt, Hg a été réalisée avec la méthode d'Ericson. Les distributions expérimentales du nombre de niveaux d'or impair sont comparées aux distributions théoriques correspondant aux modÚles vibrationnels (Alaga, Kisslinger-Sorensen) et rotationnels (Stephens, Meyer-ter-Vehn). Le modÚle d'Alaga donne la description la plus complÚte des niveaux de 193,195Au et s'accorde avec la partie inférieure de la distribution de haute énergie de Gilbert-Cameron (déduite du modÚle statistique et des données de capture neutronique). La méthode d'Ericson révÚle d'autres aspects intéressants des isotopes de Pt et Hg (p. ex. dépendance entre la densité des niveaux et la forme des noyaux ou des corrélations de paires, évidence pour des transitions de phase). En conséquence, cette méthode est un outil approprié pour l'orientation des recherches expérimentales aussi bien que théoriques des noyaux de transition

    Father-Son Farming Plans: Growing into the Farm Business

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    Vascular Smooth Muscle Progenitor Cells: Building and Repairing Blood Vessels

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    Molecular pathways that control the specification, migration, and number of available smooth muscle progenitor cells play key roles in determining blood vessel size and structure, capacity for tissue repair and remodeling, and progression of age-related disorders. Defects in these pathways will produce malformations of developing blood vessels, depletion of SMC progenitor pools for vessel wall maintenance and repair, and aberrant activation of alternative differentiation pathways in vascular disease. A better understanding of the molecular mechanisms that uniquely specify and maintain vascular SMC precursors is essential if we are to utilize advances in stem and progenitor cell biology and somatic cell reprogramming for applications directed to the vessel wall

    Security Analysis of Sensor Networks

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    Wireless sensor networks distribute a common sensing and computing task within the large number of participants that use wireless communication. Such networks require a self-organizing and energy-aware set of protocols. Several protocols have beed designed for such environments, however to make certain proof of their secureness, their formal analysis is required. In our article, we show an analysis framework capable of proving security properties of such protocols. Our methodology is based on the CSP process algebra. We will demonstrate its power by giving an attack possibility for an existing protocol, and the extensibility of the model will also be pointed
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