7,570 research outputs found

    Direct numerical simulation of fog: The sensitivity of a dissipation phase to environmental conditions

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    The sensitivity of fog dissipation to the environmental changes in radiation, liquid-water lapse rate, free tropospheric temperature and relative humidity was studied through numerical experiments designed based on the 2007-Paris Fog observations. In particular, we examine how much of the stratocumulus-thinning mechanism can be extended to the near-surface clouds or fog. When the free troposphere is warmed relative to the reference case, fog-top descends and become denser. Reducing the longwave radiative cooling via a more emissive free troposphere favors thickening the physical depth of fog, unlike cloud-thinning in a stratocumulus cloud. Drying the free troposphere allows fog thinning and promotes fog dissipation while sustaining the entrainment rate. The numerical simulation results suggest that the contribution of entrainment drying is more effective than the contribution of entrainment warming yielding the reduction in liquid water path tendency and promoting the onset of fog depletion relative to the reference case studied here. These sensitivity experiments indicate that the fog lifting mechanism can enhance the effect of the inward mixing at the fog top. However, to promote fog dissipation, an inward mixing mechanism only cannot facilitate removing humidity in the fog layer unless a sufficient entrainment rate is simultaneously sustained

    Prevalence and intensity of depression in mothers of children with beta-thalassemia major in Talghani Hospital of Gorgan, Iran

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    Background: Thalassemia is a chronic disease that it leads to psychological and social problems for parents. Mothers are at markedly increased risk of suffering from psychological distress and depression because they usually take on a considerable part of extra care that their children need.This study was designed to determine prevalence and intensity of depression in mothers with a thalassemic child. Material and Methods: In this cross - sectional study, 65 mothers of children with thalassemia major (case group) and 65 mothers of children without thalassemia major (control group) were assessed using the Beck Depression Inventory (BDI). Data were analyzed by using SPSS (v 16.0) for windows. Results: Prevalence of depression was significantly higher in case group than that in control group (84.6%vs. 56.9%, p <0.05). Moderate depression had a highest prevalence in the both groups (33.4% in case group and 30.8% in control group). Prevalence of severe depression in case group was markedly higher than that in control group (29.2% vs. 3.1% p<0.05). There was a significant difference between intensity of depression in mothers of case group that had another child with beta-thalassemia major (p<0.05). Conclusion: Mothers of children with thalassemia major are vulnerable to depression. They need psychosocial support to promote their health. © Journal of Krishna Institute of Medical Sciences University

    Quantum Discord for Generalized Bloch Sphere States

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    In this study for particular states of bipartite quantum system in 2n?2m dimensional Hilbert space state, similar to m or n-qubit density matrices represented in Bloch sphere we call them generalized Bloch sphere states(GBSS), we give an efficient optimization procedure so that analytic evaluation of quantum discord can be performed. Using this optimization procedure, we find an exact analytical formula for the optimum positive operator valued measure (POVM) that maximize the measure of the classical correlation for these states. The presented optimization procedure also is used to show that for any concave entropy function the same POVMs are sufficient for quantum discord of mentioned states. Furthermore, We show that such optimization procedure can be used to calculate the geometric measure of quantum discord (GMQD) and then an explicit formula for GMQD is given. Finally, a complete geometric view is presented for quantum discord of GBSS. Keywords: Quantum Discord, Generalized Bloch Sphere States, Dirac matrices, Bipartite Quantum System. PACs Index: 03.67.-a, 03.65.Ta, 03.65.UdComment: 26 pages. arXiv admin note: text overlap with arXiv:1107.5174 by other author

    Entrepreneurship Education in Iranian Higher Education: The Current State and Challenges

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    Entrepreneurship has long been considered a significant factor for socioeconomic growth and development because it provides millions of job opportunities, offers a variety of consumer goods and services, and generally increases national prosperity and competitiveness. Due to this positive impact of entrepreneurship, recent decades have seen a tremendous rise in entrepreneurship education at various universities and colleges around the globe, including in Iran. In the middle of this expansion remains the challenges and problems of development and changes for entrepreneurship.This paper investigates the state, trends, challenges and solutions in entrepreneurship education in Iran which emerged from an extensive review of literature. The literature reviewed indicates that entrepreneurship education in Iranian higher education faces with economic, political, social, and cultural challenges. Also this article offers some approaches and recommendations for resolving the challenges as well as encouraging and fostering entrepreneurship in higher education. The findings of this study provide valuable insights for policy makers, educators, students and graduate entrepreneurs. Stakeholders could use this study to make better choices in relation to the improvement of entrepreneurship education in Iranian higher education system
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