The effect of exchanger inhibitory peptide (XIP) on sodium-calcium exchange current in guinea pig ventricular cells

While the osteopenia associated with oestrogen deficiency is thought to arise from a relative defect in bone formation with respect to resorption, oestrogen administration itself leads to a decrease, rather than an increase, in bone formation. This decrease in bone formation, which arises from oestrogen's inhibitory effect on bone turnover, presumably masks any underlying tendency of oestrogen treatment towards stimulation of bone formation. To investigate this further, we have examined the early effect of discontinuing the administration of oestradiol-17 beta (OE2; 40 micrograms/kg) on bone formation indices in ovariectomized 13-week-old rats, before the turnover-induced increase in formation occurs. Histomorphometric indices were assessed at the proximal tibial metaphysis 0, 7, 10, 13 and 16 days following discontinuation of OE2 treatment. Measurements of body weight, uterine weight and longitudinal growth rate confirmed that there were rapid effects of OE2 deficiency on these parameters. We could detect no significant increase in bone resorption, as measured by osteoclast surface and number, until 16 days after ending treatment with OE2; this was coincidental with a reduction in bone volume. Shorter periods of OE2 deficiency were associated with a marked decrease in bone formation, as assessed by dynamic histomorphometric indices. This inhibition of bone formation was largely due to a reduction in double fluorochrome-labeled trabecular surfaces, which were decreased by approximately 70%. We conclude that ending OE2 administration in ovariectomized rats caused a striking decrease in trabecular bone formation, if such indices are assessed prior to the subsequent turnover-induced increase in formation.(ABSTRACT TRUNCATED AT 250 WORDS)     

A sampling approach to Debiasing the offline evaluation of recommender systems

Journal of Intelligent Information Systems - Offline evaluation of recommender systems (RSs) mostly relies on historical data, which is often biased. The bias is a result of many confounders that...     

An analysis of construction productivity in Malaysia

The construction industry is an industry of major strategic importance. Its level of productivity has a significant effect on national economic growth. Productivity indicators are examined. The indicators consist of labour productivity, capital productivity, labour competitiveness, capital intensity and added value content of data, which are obtained from the published census/biannual surveys of the construction industry between the years 1999 and 2011 from the Department of Statistics of Malaysia. The results indicated that there is an improvement in the labour productivity, but the value-added content is declining. The civil engineering and special trades subsectors are more productive than the residential and non-residential subsectors in terms of labour productivity because machine-for-labour substitution is a more important process in those subsectors. The capital-intensive characteristics of civil engineering and special trade works enable these subsectors to achieve higher added value per labour cost but not the capital productivity. The added value per labour cost is lower in larger organizations despite higher capital productivity. However, the capital intensity is lower and unit labour cost is higher in the larger organizations.     

Economic development and construction productivity in Malaysia

The productivity of the construction industry has a significant effect on national economic growth. Gains from higher construction productivity flow through the economy, as all industries rely on construction to some extent as part of their business investment. Contractions and expansions of economic activity are common phenomena in an economy. Three construction cycles occurred between the years 1970 and 2011 in Malaysia. The relationships between construction productivity and economic development are examined by the partial correlation method to establish the underlying factors driving the change in construction productivity. Construction productivity is statistically significantly correlated with gross domestic product (GDP) per capita in a positive direction for the 1985–98 and 1998–2009 cycles, but not the 1970–85 cycle. Fluctuations in construction activities and the influx of foreign workers underlie the changes of construction productivity in the 1985–98 cycle. There was less fluctuation in construction activities in the 1998–2009 cycle, with changes being mainly due to the fiscal stimulation policies of the government in attempting to stabilize the economy. The intensive construction of mega-projects resulted in resource constraints and cost pressures during the 1980s and 1990s. A better management of the ‘boom-bust’ nature of the construction business cycle is required to maintain the capability and capacity of the industry.     

碳酸盐岩薄储层横向预测方法

在对四川盆地川东大天池构造带的石炭系地层进行薄储层横向预测时.提出了一套模式化分析方法。此法以建工的储层序列地质模式为基础.利用测井曲线垂向分辨率高的特点.采用下同频率子波的合成地震记录,把地质、测井和地震资料有机地结合起来进行综合解释,对石炭系储层的顶、底界面及储层沉积微相进行了标定;同时研究了储层的物性变化。在该区,用上述方法对碳酸盐岩薄储层进行早期横向预测,取得了显著的地质效果。     

Impact of plant shoot architecture on leaf cooling: a coupled heat and mass transfer model

Plants display a range of striking architectural adaptations when grown at elevated temperatures. In the model plant Arabidopsis thaliana, these include elongation of petioles, and increased petiole and leaf angles from the soil surface. The potential physiological significance of these architectural changes remains speculative. We address this issue computationally by formulating a mathematical model and performing numerical simulations, testing the hypothesis that elongated and elevated plant configurations may reflect a leaf-cooling strategy. This sets in place a new basic model of plant water use and interaction with the surrounding air, which couples heat and mass transfer within a plant to water vapour diffusion in the air, using a transpiration term that depends on saturation, temperature and vapour concentration. A two-dimensional, multi-petiole shoot geometry is considered, with added leaf-blade shape detail. Our simulations show that increased petiole length and angle generally result in enhanced transpiration rates and reduced leaf temperatures in well-watered conditions. Furthermore, our computations also reveal plant configurations for which elongation may result in decreased transpiration rate owing to decreased leaf liquid saturation. We offer further qualitative and quantitative insights into the role of architectural parameters as key determinants of leaf-cooling capacity.     

Textual case-based reasoning for spam filtering: a comparison of feature-based and feature-free approaches

Spam filtering is a text classification task to which Case-Based Reasoning (CBR) has been successfully applied. We describe the ECUE system, which classifies emails using a feature-based form of textual CBR. Then, we describe an alternative way to compute the distances between cases in a feature-free fashion, using a distance measure based on text compression. This distance measure has the advantages of having no set-up costs and being resilient to concept drift. We report an empirical comparison, which shows the feature-free approach to be more accurate than the feature-based system. These results are fairly robust over different compression algorithms in that we find that the accuracy when using a Lempel-Ziv compressor (GZip) is approximately the same as when using a statistical compressor (PPM). We note, however, that the feature-free systems take much longer to classify emails than the feature-based system. Improvements in the classification time of both kinds of systems can be obtained by applying case base editing algorithms, which aim to remove noisy and redundant cases from a case base while maintaining, or even improving, generalisation accuracy. We report empirical results using the Competence-Based Editing (CBE) technique. We show that CBE removes more cases when we use the distance measure based on text compression (without significant changes in generalisation accuracy) than it does when we use the feature-based approach.     

鄂黄长江大桥主桥施工阶段横向应力研究

通过模拟鄂黄长江公路大桥主桥梁段悬浇施工过程,建立梁段有限元各阶段应力分析模型,探讨不同施工阶段梁段横向应力增长规律,并将几种横梁预应力筋施工方案作分析比较,提出合理的预应力筋张拉次序.     

芜湖长江大桥

芜湖长江大桥,是一座公路、铁路两用桥,在极其恶劣的环境条件下,采用了跨径为(180 312 180)m的斜拉桥,其特点为塔矮,塔高与中跨跨径之比为0.11,边跨跨径大,边跨与中跨的比值0.577,铁路荷载很大,动力作用大,提高梁的刚度,采取了三点措施,以满足铁路运行的需要.