72 research outputs found

    Thermodynamical description of interacting entropy-corrected new agegraphic dark energy

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    To explain the accelerating universe driven by dark energy, a so-called "entropy-corrected new agegraphic dark energy" (ECNADE), was recently proposed with the help of quantum corrections to the entropy-area relation in the framework of loop quantum cosmology. Using this definition, we study its thermodynamical features including entropy and energy conservation. We discuss the thermodynamical interpretation of the interaction between ECNADE and dark matter in a non-flat universe bounded by the apparent horizon. We obtain a relation between the interaction term of the dark components and thermal fluctuation.Comment: 8 pages, version accepted for publication in Europhysics Letters (2011

    Using Bayesian Model Averaging (BMA) to calibrate probabilistic surface temperature forecasts over Iran

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    Using Bayesian Model Averaging (BMA), an attempt was made to obtain calibrated probabilistic numerical forecasts of 2-m temperature over Iran. The ensemble employs three limited area models (WRF, MM5 and HRM), with WRF used with five different configurations. Initial and boundary conditions for MM5 and WRF are obtained from the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) and for HRM the initial and boundary conditions come from analysis of Global Model Europe (GME) of the German Weather Service. The resulting ensemble of seven members was run for a period of 6 months (from December 2008 to May 2009) over Iran. The 48-h raw ensemble outputs were calibrated using BMA technique for 120 days using a 40 days training sample of forecasts and relative verification data. <br><br> The calibrated probabilistic forecasts were assessed using rank histogram and attribute diagrams. Results showed that application of BMA improved the reliability of the raw ensemble. Using the weighted ensemble mean forecast as a deterministic forecast it was found that the deterministic-style BMA forecasts performed usually better than the best member's deterministic forecast

    Modeling of Individual and Organizational Factors Affecting Traumatic Occupational Injuries Based on the Structural Equation Modeling: A Case Study in Large Construction Industries

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    Background: Individual and organizational factors are the factors influencing traumatic occupational injuries. Objectives: The aim of the present study was the short path analysis of the severity of occupational injuries based on individual and organizational factors. Materials and Methods: The present cross-sectional analytical study was implemented on traumatic occupational injuries within a ten-year timeframe in 13 large Iranian construction industries. Modeling and data analysis were done using the structural equation modeling (SEM) approach and the IBM SPSS AMOS statistical software version 22.0, respectively. Results: The mean age and working experience of the injured workers were 28.03 ± 5.33 and 4.53 ± 3.82 years, respectively. The portions of construction and installation activities of traumatic occupational injuries were 64.4% and 18.1%, respectively. The SEM findings showed that the individual, organizational and accident type factors significantly were considered as effective factors on occupational injuries’ severity (P < 0.05). Conclusions: Path analysis of occupational injuries based on the SEM reveals that individual and organizational factors and their indicator variables are very influential on the severity of traumatic occupational injuries. So, these should be considered to reduce occupational accidents’ severity in large construction industries

    Velocity Curve Analysis of the Spectroscopic Binary Stars V373 Cas, V2388 Oph, V401 Cyg, GM Dra, V523 Cas, AB And, and HD 141929 by Artificial Neural Networks

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    We used an Artificial Neural Network (ANN) to derive the orbital parameters of spectroscopic binary stars. Using measured radial velocity data of seven double-lined spectroscopic binary systems V373 Cas, V2388 Oph, V401 Cyg, GM Dra, V523 Cas, AB And, and HD 141929, we found corresponding orbital and spectroscopic elements. Our numerical results are in good agreement with those obtained by others using more traditional methods.Comment: 13 pages, 8 figures, 14 Table

    Application of a New Non-Linear Least Squares Velocity Curve Analysis Technique for Spectroscopic Binary Stars

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    Using measured radial velocity data of nine double lined spectroscopic binary systems NSV 223, AB And, V2082 Cyg, HS Her, V918 Her, BV Dra, BW Dra, V2357 Oph, and YZ Cas, we find corresponding orbital and spectroscopic elements via the method introduced by Karami & Mohebi (2007a) and Karami & Teimoorinia (2007). Our numerical results are in good agreement with those obtained by others using more traditional methods.Comment: 6 pages, 3 figures. Accepted for publication in Astrophysics & Space Scienc

    The Role of mathematical thought in the improvement of architecture students’ abilities on logical aspects of design

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    Background and Objectives: Architectural education as a challengeable subject is dependent on multiple variables. Since formation of an architect character and learning design abilities are related to this subject, it is so sensitive.  Historically, the role of mathematics and application of its different aspects in architectural design is indisputable. While recent decades have witnessed a high level of interaction between mathematics and architecture in the world, mathematics in architectural education in Iran is still being taught as a basic course through the lecture method. A great concern in learning architectural design is how to apply the basic courses in design process. Methods: According to the necessity of revising the role of mathematics in education of architectural design, and developing new approaches to apply mathematical thought in logical process of design, the present study aims to test an educational model in an environment consisting of test and control groups in the Basic Design 1 & 2 courses, using the proposed model of Lawson as well as quasi-experimental research method. The research subjects are selected among BA students of Islamic Azad University of Urmia (n=52). They provided logical solutions for design problems, using algebraic, arithmetic, geometric and symbolic aspects of mathematics. The subjects’ design abilities were evaluated by the performance measurement method based on verdict criteria. The researchers determined two groups of mathematical and architectural design measurement criteria. For design, the criteria included design conceptual quality, spatial and functional arrangement, form combination, presentation quality, creativity and final grade.  Findings: The final grades of four research projects executed in two studios were respectively for design 62.57,66.29, 71.30, 75.31 and for mathematics 64.99, 69.27, 71.72 and 74.9. The correlation between design and mathematics evaluation scores for project 1 of the studio 1 (ƿ=0.594) and project 2 of the studio 2 (ƿ=0.604) is independently obvious which indicates the strong combination between mathematics and design aspects in these projects. For the project 2 of the studio 1, the correlation was low (ƿ= 0.166). The possible explanation could be based on the lack of real materials application and the experiment of altering theory analysis to practical analysis. The correlation between design evaluation scores and mathematics application (ƿ=0.384) reveals a positive role for mathematical thought in developing logical solutions and general quality of design. Conclusion: Findings of this study directly refers to the correspondence between research assumptions and the verdict criteria. The findings indicate that students’ performance in test group is better than the students in control group in all criteria except the presentation. The best performance by subjects of the test group means that their ability in creating solution concept has much improved compared with the control group as a result of manipulating the independent variable which is the education method in this study. This improvement couldn’t be related to other unrelated independent variables, because these variables have been either controlled or their effect has been studied through the pre-test. Stated on the findings in analyzing the general quality of design, students provided complicated geometric patterns in their design as logical, creative and efficient solutions through realizing their mathematical principles. Acquiring and developing the design schema based on design problems in the Basic design studios results the improvement of the students’ ability in logical aspects of design.   ===================================================================================== COPYRIGHTS  ©2020 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.  ====================================================================================

    Psychedelics Promote Structural and Functional Neural Plasticity.

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    Atrophy of neurons in the prefrontal cortex (PFC) plays a key role in the pathophysiology of depression and related disorders. The ability to promote both&nbsp;structural and functional plasticity in the PFC has been hypothesized to underlie the fast-acting antidepressant properties of the dissociative anesthetic ketamine. Here, we report that, like ketamine, serotonergic psychedelics are capable of robustly increasing neuritogenesis and/or spinogenesis both in&nbsp;vitro and in&nbsp;vivo. These changes in neuronal structure are accompanied by increased synapse number and function, as measured by fluorescence microscopy and electrophysiology. The structural changes induced by psychedelics appear to result from stimulation of the TrkB, mTOR, and 5-HT2A signaling pathways and could possibly explain the clinical effectiveness of these compounds. Our results underscore the therapeutic potential of psychedelics and, importantly, identify several lead scaffolds for medicinal chemistry efforts focused on developing plasticity-promoting compounds as safe, effective, and fast-acting treatments for depression and related disorders

    Interacting entropy-corrected new agegraphic dark energy in Brans-Dicke cosmology

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    Motivated by a recent work of one of us [1], we extend it by using quantum (or entropy) corrected new agegraphic dark energy in the Brans-Dicke cosmology. The correction terms are motivated from the loop quantum gravity which is one of the competitive theories of quantum gravity. Taking the non-flat background spacetime along with the conformal age of the universe as the length scale, we derive the dynamical equation of state of dark energy and the deceleration parameter. An important consequence of this study is the phantom divide scenario with entropy-corrected new agegraphic dark energy. Moreover, we assume a system of dark matter, radiation and dark energy, while the later interacts only with dark matter. We obtain some essential expressions related with dark energy dynamics. The cosmic coincidence problem is also resolved in our model.Comment: 16 pages, no figure, accepted for publication in Gen. Relativ. Gra
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