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11.
This study introduces measures to identify resonant (concentration of energy in a single or a few frequencies) or unfavorable earthquake ground motions. Probabilistic measures based on the entropy rate and the geometric properties of the power spectral density function (PSDF) of the ground acceleration are developed first. Subsequently, deterministic measures for the frequency content of the ground acceleration are also developed. These measures are then used for identifying resonance and criticality in stochastic earthquake models and 110 acceleration records measured at rock, stiff, medium and soft soil sites. The unfavorable earthquake record for a given structure is defined as the record having a narrow frequency content and dominant frequency close to the structure fundamental natural frequency. Accordingly, the measures developed in this study may provide a basis for selecting records that are capable of producing the highest structural response. Numerical verifications are provided on damage caused to structures by identified resonant records. 相似文献
12.
Yu Wang Rachel D. Lowe Yara X. Mejia Holger Feindt Siegfried Steltenkamp Thomas P. Burg 《Biomicrofluidics》2013,7(2)
Surface analysis is critical for the validation of microfluidic surface modifications for biology, chemistry, and physics applications. However, until now quantitative analytical methods have mostly been focused on open surfaces. Here, we present a new fluorescence imaging method to directly measure the surface coverage of functional groups inside assembled microchannels over a wide dynamic range. A key advance of our work is the elimination of self-quenching to obtain a linear signal even with a high density of functional groups. This method is applied to image the density and monitor the stability of vapor deposited silane layers in bonded silicon/glass micro- and nanochannels. 相似文献
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Moslem Bahmani Abbas Bahram Jed A Diekfuss Saeed Arsham 《Journal of sports sciences》2013,31(20):2318-2330
ABSTRACTThe aims of this study were to (1) to explore attentional strategies in expert judo players and (2) investigate how attentional focus affects performance effectiveness and perceptions of workload in expert judo players during real competitions. Fourteen expert male judo players participated in the study. A simulated recall method was used following participants’ competition to explore contents of attention qualitatively. The data analysis process for the qualitative portion of the study was an iterative process between inductive and deductive analyses. Quantitative analyses of performance outcomes and workload were then associated with the qualitative findings. Qualitative results revealed that the focus of attention was dynamic and complex, with technical aspects of the movements as the highest identified focus. Quantitative analyses revealed that reporting a lower quantity of attentional cues and higher percentage of focus on opponent resulted in higher performance effectiveness and less perceptions of workload. This study indicates that cognitive control and automaticity may work in a synergistic manner for successful skill execution in expert performance. 相似文献
14.
Computational models that ensure accurate and fast responses to the variations in operating conditions,such as the cell temperature and relative humidity(RH),are essential monitoring tools for the real-time control of proton exchange membrane(PEM) fuel cells.To this end,fast cell-area-averaged numerical simulations are developed and verified against the present experiments under various RH levels.The present simulations and measurements are found to agree well based on the cell voltage(polarizat... 相似文献
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Monica McLean Andrea Abbas Paul Ashwin 《British Journal of Sociology of Education》2013,34(2):262-280
This paper illustrates how critical use of Basil Bernstein's theory illuminates the mechanisms by which university knowledge, curriculum and pedagogy both reproduce and interrupt social inequalities. To this end, empirical examples are selected from the findings of the ESRC-funded project ‘Pedagogic Quality and Inequality in University First Degrees' (RES-062-23-1438, November 2008–January 2012). The project investigated sociology-related social science degrees in four social science departments in universities in different positions in influential UK higher education league tables. A Bernsteinian lens throws fresh light on how university education might contribute to a more egalitarian society. 相似文献
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Ethical concerns of educational technologists in Iran 总被引:1,自引:0,他引:1
Abbas Johari 《Educational technology research and development : ETR & D》2000,48(4):107-109
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Ishrat Husain Ramesh Chander Jitendra Kumar Saxena Abbas Ali Mahdi Farzana Mahdi 《Indian journal of clinical biochemistry : IJCB》2015,30(1):72-77
The antidyslipidemic activity of Ocimum sanctum leaf extract was studied in streptozotocin induced diabetic rats. In this model, there was significant increase in plasma markers of diabetic-dyslipidemia following diminution of lipid metabolizing enzymes. Oral administration of leaf extract (500 mg/kg b.w.p.o.) for 15 days resulted in significant decrease in diabetogenic and dyslipidemia parameters; namely blood glucose, glycosylated hemoglobin, lipid peroxide, free fatty acids, small dense low density lipoprotein, lipid and protein components of plasma lipoproteins, adipose and liver. The regulation of lipids was accompanied by stimulation of postheparin lipolytic activity, reactivation of lecithin cholesterol acyl transferase and hepatic lipoprotein lipase enzymes. The results of the present study demonstrated antidyslipidemic and antioxidant activities in leaf extract of O. sanctum which could be used in prevention of diabetic-dyslipidemia and related complications. 相似文献
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Ghizal Fatima Abbas Ali Mahdi Siddharth Kumar Das Baby Anjum Nar Singh Verma Puneet Kumar Ragini Shrivastava 《Indian journal of clinical biochemistry : IJCB》2012,27(4):340-343
The present study was designed to test the hypothesis of a circadian variation in circulating levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in women with fibromyalgia syndrome (FMS). Serum levels of IL-6 and TNF-α were measured at 4 h intervals of the day in 50 women with FMS satisfying American College of Rheumatology criteria for FMS (age 36.68 ± 9.89) as well as 50 healthy control women (age 32.82 ± 10.53). Serum TNF-α levels were substantially increased in patients with FMS but showed no circadian variation. In contrast, no difference in the levels of IL-6 was found. Moreover, there was also no circadian variation in both the groups of patients and controls. We conclude that no circadian pattern exists in the circulating levels of serum IL-6 and TNF-α in patients with FMS, although TNF-α levels are found raised in patients with FMS. 相似文献