混凝土搅拌方式变更对工程造价的影响

以某输变电工程为例,通过对该工程混凝土搅拌方式变更前后工程造价进行经济分析,将其对工程造价影响的因素和程度进行了总结和量化,以期为施工单位提供决策依据。     

开封市区地热水可开采量评价

评价地热水可采量时，评价方法的选用对于评价的结果有着重要的意义。根据开封市区地下热流系统的特征和已有的地热资料，可采量的评价方法可选用侧向迳流补给法和均匀布井法(改进的均匀布井法)这两种方法。通过这两种方法分别对开封市区300～1600m热储层的可采热水量进行了评价，分析得出改进的均匀布井法计算结果更为合理。故以改进的均匀布井法计算的可采水量作为开封市区的允许开采量。     

中国城镇化进程中生态效率的变化研究

基于投入导向的规模报酬不变的超效率数据包络分析方法,运用EMS1.3.0软件测算2003-2009年全国各省市(区)的生态效率评价值,并通过建立城镇化的生态效率效应模型,实证检验中国城镇化进程中的生态效率变化趋势及其影响因素.研究结果表明,城镇化水平与生态效率之间呈正U型变化关系,即在城镇化的初期阶段,生态效率不断降低...     

土坝漫顶后冲沟网形成模拟

根据土坝漫顶后冲沟网形成的特点,建立了能够模拟土坝漫顶后冲沟网形成的元胞自动机模型。在元胞自动机模型中采用坡降模式模拟水流运动,采用冲刷率公式模拟坡面冲刷,确定了坡面径流和坡面冲刷规则。在计算中考虑了地形随机起伏变化和坡面抗冲性能差异2个影响因素,得出不同因素对冲沟网形成的影响。结果表明:单一考虑地形随机起伏变化形成的冲沟网较顺直,综合考虑2个方面影响的计算结果比较合理。     

Cardiovascular,Metabolic and Inflammatory Changes after Ovariectomy and Estradiol Substitution in Hereditary Hypertriglyceridemic Rats

Background: If menopause is really independent risk factor for cardiovascular disease is still under debate. We studied if ovariectomy in the model of insulin resistance causes cardiovascular changes, to what extent are these changes reversible by estradiol substitution and if they are accompanied by changes in other organs and tissues. Methods: Hereditary hypertriglyceridemic female rats were divided into three groups: ovariectomized at 8th week (n = 6), ovariectomized with 17-β estradiol substitution (n = 6), and the sham group (n = 5). The strain of abdominal aorta measured by ultrasound, expression of vascular genes, weight and content of myocardium and also non-cardiac parameters were analyzed. Results: After ovariectomy, the strain of abdominal aorta, expression of nitric oxide synthase in abdominal aorta, relative weight of myocardium and of the left ventricle and circulating interleukin-6 decreased; these changes were reversed by estradiol substitution. Interestingly, the content of triglycerides in myocardium did not change after ovariectomy, but significantly increased after estradiol substitution while adiposity index did not change after ovariectomy, but significantly decreased after estradiol substitution. Conclusion: Vascular and cardiac parameters under study differed in their response to ovariectomy and estradiol substitution. This indicates different effects of ovariectomy and estradiol on different cardiovascular but also extracardiac structures.     

GLDAS Noah模型水文产品与中国地面观测及卫星观测数据的对比

全球陆面数据同化系统(GLDAS)是全球水循环研究的重要数据源,基于重力卫星(GRACE)观测数据、中国的地面降水与径流观测数据,从模拟数据与观测数据之间的偏差、相关性及时空分布一致性角度,对GLDAS两个版本(GLDAS-1及GLDAS-2)的Noah模型模拟水文产品进行了评估。结果表明,GLDAS与GRACE TWS陆地水蓄量(TWS)变化情况在中国大部分地区一致性较差,且GLDAS-1与GLDAS-2均不能充分反映GRACE TWS数据的季节性变化规律;GLDAS-1与GLDAS-2模拟的中国外流区的径流明显低于观测径流,同时长江流域与松花江流域GLDAS-2模拟径流的精度远比GLDAS-1模拟径流的精度高;GLDAS-1与GLDAS-2在中国的外流流域的蒸散发均呈高估现象,且GLDAS-1的高估程度大于GLDAS-2。     

Effects of hypoxia/hypercapnia on the metablism of Callosobruchus chinensis (L.) larvae

Insects that are pests of stored products are highly tolerant to low O₂ levels (hypoxia) and high carbon dioxide levels (hypercapnia) for long periods, but the underlying mechanism remains unclear. In the present study, we investigated the metabolic profiles of Callosobruchus chinensis (L.) larvae held under 2% O₂+18% CO₂ (both v/v) for 24, 48, and 96 h using gas chromatography–time-of-flight mass spectrometry (GC-TOF-MS), their corresponding control groups under normoxia were also investigated simultaneously. We found that the relative quantity of 91, 24, and 48 metabolites were altered at these three time periods, respectively. The metabolites were principally carbohydrates, organic acids, amino acids, and free fatty acids, 30 of these metabolites with high accuracy of qualitative identification and biological functions were chosen for further analyses. These were intermediates of the citric acid cycle, glycolysis, fatty acid synthesis, and amino acid metabolism. Based on our results, levels of organic acids increased, while levels of amino acids decreased, suggesting that metabolism was shifting from aerobic to anaerobic. Lipid metabolism may be relatively less important; the number of fatty acids exhibiting significant changes in level was quite small. The metabolic profiles changed dynamically over time, with the largest changes evident for 24 h of hypoxia/hypercapnia, followed by 96 h, and only a little change has been shown on 48 has revealed by heatmap and pathway topological analysis. Therefore, we present direct evidence that the metabolism of insect pests of stored products is influenced by complex environmental stressors.     

Measuring Developmental Changes in Alcohol Expectancies.

The goal of this study was to measure shifts in alcohol expectancies from childhood into adolescence while controlling for changes in the psychometric properties of the instrument. One thousand nine hundred ninety-three 4th-grade and 1,632 9th-grade students from South Dakota rated the likelihood that 23 outcomes would result from alcohol use. These expectancies were modeled using a 2-factor confirmatory factor analysis. After differences in the psychometric properties of the instrument were controlled, the cohorts were distinguished by a large difference in Alcohol Positivity, with older participants viewing alcohol's effects more positively. Additionally, older participants displayed greater Alcohol Potency, believing that alcohol has a larger impact on all outcomes. There were also significant differences in the interpretation of the alcohol expectancies items across cohorts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Resolving Apparent Contradictions Concerning the Relationships Among Fear or Anxiety and Aggression During Lactation: Theoretical Comment on D'Anna, Stevenson, and Gammie (2005).

Pregnancy and lactation involve dramatic changes in behavior and physiology necessary for the successful production and sustenance of offspring. This requires numerous processes to emerge and be coordinated in a finely tuned manner. Reduced corticotropin releasing factor (CRF) receptor activity and hypothalamic-pituitary-adrenal function are thought to be involved in numerous functions during lactation, such as reducing fear and anxiety, which in turn, is proposed to disinhibit aggressive behaviors. K. L. D'Anna, S. A. Stevenson, and S. C. Gammie (2005) reported that central infusion of urocortin 1 and 3, anxiogenic peptides that bind to CRF receptors, reduce maternal aggression in lactating mice and alter neural c-fos expression. However, the relationship between stress hormones and where they act, emotional state, and aggression during lactation is complicated, and our understanding of how these factors influence each other might benefit from a comprehensive reevaluation of these literatures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structure–Function Relationships in the Human P-Glycoprotein (ABCB1): Insights from Molecular Dynamics Simulations

P-Glycoprotein (P-gp) is a transmembrane protein belonging to the ATP binding cassette superfamily of transporters, and it is a xenobiotic efflux pump that limits intracellular drug accumulation by pumping compounds out of cells. P-gp contributes to a reduction in toxicity, and has broad substrate specificity. It is involved in the failure of many cancer and antiviral chemotherapies due to the phenomenon of multidrug resistance (MDR), in which the membrane transporter removes chemotherapeutic drugs from target cells. Understanding the details of the ligand–P-gp interaction is therefore critical for the development of drugs that can overcome the MDR phenomenon, for the early identification of P-gp substrates that will help us to obtain a more effective prediction of toxicity, and for the subsequent outdesign of substrate properties if needed. In this work, a series of molecular dynamics (MD) simulations of human P-gp (hP-gp) in an explicit membrane-and-water environment were performed to investigate the effects of binding different compounds on the conformational dynamics of P-gp. The results revealed significant differences in the behaviour of P-gp in the presence of active and non-active compounds within the binding pocket, as different patterns of movement were identified that could be correlated with conformational changes leading to the activation of the translocation mechanism. The predicted ligand–P-gp interactions are in good agreement with the available experimental data, as well as the estimation of the binding-free energies of the studied complexes, demonstrating the validity of the results derived from the MD simulations.