969 research outputs found

    Goal Orientation in Teams: The Role of Diversity

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    Organizations make increasingly use of teams as their basic structure, making it more and more important to determine what enables optimal team functioning. Over the past decades, the goals people focus on in achievement settings (i.e. goal orientation) is shown to be highly important for individual behavior. Nevertheless, little is known on how this plays out in a team context. The present dissertation focuses on uncovering the role of team composition in goal orientation on team functioning, with special emphasis on the role of diversity. In a series of experimental and field studies, we examine several important areas in need of clarification leading to several key insights. First, team members’ goal orientation may help or hurt teams dealing with ethnic diversity. Second, effects of mean levels of goal orientation on team performance may be dependent on other factors (moderators). Third, diversity in goal orientation is an important overlooked variable in the literature that plays a large role in team performance. Fourth, both group information elaboration and group efficiency are relevant underlying processes of this relationship. Fifth, team reflexivity may counteract the negative effects of diversity in goal orientation. Finally, a coordinating team leader may bring about the positive potential of diversity in goal orientation

    Massive Spin Collective Mode in Quantum Hall Ferromagnet

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    It is shown that the collective spin rotation of a single Skyrmion in quantum Hall ferromagnet can be regarded as precession of the entire spin texture in the external magnetic field, with an effective moment of inertia which becomes infinite in the zero g-factor limit. This low-lying spin excitation may dramatically enhance the nuclear spin relaxation rate via the hyperfine interaction in the quantum well slightly away from filling factor equal one.Comment: 4 page

    NMR Constraints Analyser: a web-server for the graphical analysis of NMR experimental constraints

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    Nuclear magnetic resonance (NMR) spectroscopy together with X-ray crystallography, are the main techniques used for the determination of high-resolution 3D structures of biological molecules. The output of an NMR experiment includes a set of lower and upper limits for the distances (constraints) between pairs of atoms. If the number of constraints is high enough, there will be a finite number of possible conformations (models) of the macromolecule satisfying the data. Thus, the more constraints are measured, the better defined these structures will be. The availability of a user-friendly tool able to help in the analysis and interpretation of the number of experimental constraints per residue, is thus of valuable importance when assessing the levels of structure definition of NMR solved biological macromolecules, in particular, when high-quality structures are needed in techniques such as, computational biology approaches, site-directed mutagenesis experiments and/or drug design. Here, we present a free publicly available web-server, i.e. NMR Constraints Analyser, which is aimed at providing an automatic graphical analysis of the NMR experimental constraints atom by atom. The NMR Constraints Analyser server is available from the web-page http://molsim.sci.univr.it/constrain

    Interaction of reed and acoustic resonator in clarinetlike systems

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    Sound emergence in clarinetlike instruments is investigated in terms of instability of the static regime. Various models of reed-bore coupling are considered, from the pioneering work of Wilson and Beavers ["Operating modes of the clarinet", J. Acoust. Soc. Am. 56, 653--658 (1974)] to more recent modeling including viscothermal bore losses and vena contracta at the reed inlet. The pressure threshold above which these models may oscillate as well as the frequency of oscillation at threshold are calculated. In addition to Wilson and Beavers' previous conclusions concerning the role of the reed damping in the selection of the register the instrument will play on, the influence of the reed motion induced flow is also emphasized, particularly its effect on playing frequencies, contributing to reduce discrepancies between Wilson and Beavers' experimental results and theory, despite discrepancies still remain concerning the pressure threshold. Finally, analytical approximations of the oscillating solution based on Fourier series expansion are obtained in the vicinity of the threshold of oscillation. This allows to emphasize the conditions which determine the nature of the bifurcation (direct or inverse) through which the note may emerge, with therefore important consequences on the musical playing performances

    Spatial correlations between MRI-derived wall shear stress and vessel wall thickness in the carotid bifurcation

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    BACKGROUND: To explore the possibility of creating three-dimensional (3D) estimation models for patient-specific wall thickness (WT) maps using patient-specific and cohort-averaged WT, wall shear stress (WSS), and vessel diameter maps in asymptomatic atherosclerotic carotid bifurcations. METHODS: Twenty subjects (aged 75 ± 6 years [mean ± standard deviation], eight women) underwent a 1.5-T MRI examination. Non-gated 3D phase-contrast gradient-echo images and proton density-weighted echo-planar images were retrospectively assessed for WSS, diameter estimation, and WT measurements. Spearman's ρ and scatter plots were used to determine correlations between individual WT, WSS, and diameter maps. A bootstrapping technique was used to determine correlations between 3D cohort-averaged WT, WSS, and diameter maps. Linear regression between the cohort-averaged WT, WSS, and diameter maps was used to predict individual 3D WT. RESULTS: Spearman's ρ averaged over the subjects was - 0.24 ± 0.18 (p < 0.001) and 0.07 ± 0.28 (p = 0.413) for WT versus WSS and for WT versus diameter relations, respectively. Cohort-averaged ρ, averaged over 1000 bootstraps, was - 0.56 (95% confidence interval [- 0.74,- 0.38]) for WT versus WSS and 0.23 (95% confidence interval [- 0.06, 0.52]) for WT versus diameter. Scatter plots did not reveal relationships between individual WT and WSS or between WT and diameter data. Linear relationships between these parameters became apparent after averaging over the cohort. Spearman's ρ between the original and predicted WT maps was 0.21 ± 0.22 (p < 0.001). CONCLUSIONS: With a combination of bootstrapping and cohort-averaging methods, 3D WT maps can be predicted from the individual 3D WSS and diameter maps. The methodology may help to elucidate pathological processes involving WSS in carotid atherosclerosis

    Study on Solar KANG Heating System for Cold Areas

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    AbstractThe current rural traditional heated kang cannot meet people's increasing requirements of comfort and environmental protection. This paper propose solar kang heating system in cold regions. System performance and heating effect were analyzed. We selected two typical rooms. One was set in traditional kang, and the other one was solar Kang type. Using temperature recording instrument and 64 roads inspection instrument and other instruments, we test the indoor temperature and the kang surface temperature of two rooms. Solar kang thermal resistance, heat storage, heat dissipation and heating effect were analyzed and compared. The results of the study show this system have the smaller fluctuation, more comfort while alleviating the kang surface overheat or super-cooling problem. It satisfied the requirements of indoor thermal comfort. The warming rate is 5.17°C/h, and the cooling rate is 3.01°C/h. These are slower than traditional Huokang speed. It improved the heat storage capacity of kang body with surface heat dissipation 1237W. Average temperature of the solar kang heating room was improved 3.28°C. It gets the smaller indoor temperature fluctuation. PMV values are concentrated about -0.5, and this basically meet the requirements of the user comfort

    Family history is neglected in the work-up of patients with colorectal cancer: a quality assessment using cancer registry data

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    In the diagnostic work-up of hereditary non-polyposis colorectal cancer (HNPCC, Lynch syndrome), high-risk patients can be identified using information from the family history on cancer (‘Amsterdam criteria’ and ‘Bethesda guidelines’). To investigate to what extent the medical specialists apply these criteria to patients with colorectal carcinoma and a suspicion of HNPCC, we collected information on diagnostic work-up of 224 patients of seven hospitals in the region of the Comprehensive Cancer Centre West in Leiden, The Netherlands. These patients were diagnosed with colorectal cancer between 1999 and 2001 and satisfied at least one of the Bethesda guidelines. A complete family history was recorded for 38 of the 244 patients (16%). Patients with a complete family history were more likely to be referred to the Clinical Genetic Centre than those with an incomplete or absent family history (53% vs. 13% and 4%, respectively; P < 0.0001), and more likely to be analyzed for microsatellite instability (MSI), which is a characteristic of HNPCC (34% vs. 6% and 1%, respectively; P < 0.0001). We conclude that the family history is neglected in the majority of patients with colorectal cancer and MSI-analysis is only performed in a small proportion of the patients that meet the guidelines for this analysis

    A non-catecholamine-producing sympathetic paraganglioma of the spermatic cord: the importance of performing candidate gene mutation analysis

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    textabstractBackground: Catecholamine-producing tumours are called pheochromocytomas when they are located in the adrenal gland and sympathetic paragangliomas when they are located elsewhere in the abdomen. Rarely these tumours do not produce catecholamines and even more rarely they arise in the spermatic cord. Over the past decade, systematic mutation analysis of apparently sporadic cases of pheochromocytomas and paragangliomas has elucidated the frequent presence of germ line mutations in one of five candidate genes, including RET, VHL, SDHB, SDHC, and SDHD. Clinical history and methods: We describe a 45-year-old man with a non catecholamine-producing paraganglioma of the spermatic cord. We performed SDHB immunohistochemistry and performed mutation analysis of the SDHB, SDHC, and SDHD genes. Results: There was no staining of tumour cells with SDHB immunohistochemistry, indicative of an SDH mutation. Mutation analysis demonstrated a germ line SDHD mutation (p.Val147Met). Conclusions: Systematic mutation analysis is required in paraganglioma patients for the detection of germ line mutations. This should be preceded by SDHB immunohistochemistry to limit the number of genes to be tested
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