Can anomalies of fetal brain circulation be useful in the management of growth restricted fetuses?

Assessment of the fetal cerebral circulation provides important information on the hemodynamic changes associated with chronic hypoxia and intrauterine growth restriction. Despite the incorporation of new US parameters, the landmark for the fetal brain hemodynamic evaluation is still the middle cerebral artery. However, new vascular territories, such as the anterior and posterior cerebral arteries, might provide additional information on the onset of the brain sparing effect. The fractional moving blood volume estimation and three-dimensional power Doppler ultrasound indices are new techniques that seem to be promising in indentifying cases at earlier stages of vascular deterioration; still, they are not available for clinical application and more information is needed on the reproducibility and advantages of three-dimensional power Doppler ultrasound blood flow indices. In the past, the brain sparing effect was considered as a protective mechanism; however, recent information challenges this concept. There is growing evidence of an association between brain sparing effect and increased risk of abnormal neurodevelopment after birth. Even in mild late-onset intrauterine growth restriction affected fetuses with normal umbilical artery blood flow, increased cerebral blood perfusion can be associated with a substantial risk of abnormal neuroadaptation and neurodevelopment during childhood. © 2012 John Wiley & Sons, Ltd.     

Hepatitis A Outbreaks and Environmental Circulation of Genotype IA Strains in the São Paulo City, 2017–2018

Food and Environmental Virology - Hepatitis A virus (HAV) is the major cause of enterically transmitted infectious hepatitis. Between 2016 and 2017, the number of confirmed cases of hepatitis A...     

Effects of lead exposure on salivary glands of rats: insights into the oxidative biochemistry and glandular morphology

Environmental Science and Pollution Research - This study aimed to investigate the effects of lead (Pb) exposure on parotid and submandibular glands through morphological aspects as well as the...     

Evaluation of numerical simulations of CO2 transport in a city block with field measurements

Studying urban air-transport phenomena is highly complex, because of the heterogenous flow patterns that can arise. The main reason for these is the variable topology of urban areas, however, there is a large number of influencing variables such as meteorological conditions (e.g., wind situation, temperature) and anthropogenic factors such as traffic emissions. During a one-year CO₂ measurement campaign in the city of Basel, Switzerland, steep CO₂ gradients were measured around a large building. The concentration differences showed a strong dependency on the local flow regimes. Analysis of the field data alone did not provide a complete explanation for the mechanisms underlying the observed phenomena. The key numerical parameters were defined and the influence of turbulent kinetic energy dependency on the time interval for the Reynolds decomposition was studied. A Reynolds-Average Navier-Stokes Computational Fluid Dynamics (CFD) approach was applied in the study area and the CO₂ concentrations were simulated for six significant meteorological situations and compared to the measured data. Two flow regimes dependent on the wind situation, which either enhanced or suppressed the concentration of CO₂ in the street canyon, were identified. The enhancement of CO₂ in the street canyon led to a large difference in CO₂ concentration between the backyard- and street-sides of a building forming the one wall of the canyon. The specific characteristics of the flow patterns led to the identification of the processes determining the observed differences in CO₂ concentrations. The combined analysis of measurement and modeling showed the importance of reliable field measurements and CFD simulations with a high spatial resolution to assess transport mechanisms in urban areas.     

Modelling spatial patterns of correlations between concentrations of heavy metals in mosses and atmospheric deposition in 2010 across Europe

Background

This paper aims to investigate the correlations between the concentrations of nine heavy metals in moss and atmospheric deposition within ecological land classes covering Europe. Additionally, it is examined to what extent the statistical relations are affected by the land use around the moss sampling sites. Based on moss data collected in 2010/2011 throughout Europe and data on total atmospheric deposition modelled by two chemical transport models (EMEP MSC-E, LOTOS-EUROS), correlation coefficients between concentrations of heavy metals in moss and in modelled atmospheric deposition were specified for spatial subsamples defined by ecological land classes of Europe (ELCE) as a spatial reference system. Linear discriminant analysis (LDA) and logistic regression (LR) were then used to separate moss sampling sites regarding their contribution to the strength of correlation considering the areal percentage of urban, agricultural and forestry land use around the sampling location. After verification LDA models by LR, LDA models were used to transform spatial information on the land use to maps of potential correlation levels, applicable for future network planning in the European Moss Survey.

Results

Correlations between concentrations of heavy metals in moss and in modelled atmospheric deposition were found to be specific for elements and ELCE units. Land use around the sampling sites mainly influences the correlation level. Small radiuses around the sampling sites examined (5 km) are more relevant for Cd, Cu, Ni, and Zn, while the areal percentage of urban and agricultural land use within large radiuses (75–100 km) is more relevant for As, Cr, Hg, Pb, and V. Most valid LDA models pattern with error rates of <?40% were found for As, Cr, Cu, Hg, Pb, and V. Land use-dependent predictions of spatial patterns split up Europe into investigation areas revealing potentially high (=?above-average) or low (=?below-average) correlation coefficients.

Conclusions

LDA is an eligible method identifying and ranking boundary conditions of correlations between atmospheric deposition and respective concentrations of heavy metals in moss and related mapping considering the influence of the land use around moss sampling sites.

     

STATISTICAL LOW FLOW ESTIMATION USING GIS ANALYSIS IN HUMID MONTANE REGIONS IN PUERTO RICO1

ABSTRACT: Statistical analysis of watershed parameters derived using a Geographical Information system (GIS) was done to develop equations for estimating the 7d–10yr, 30d–10yr, and 7d–2yr low flow for watersheds in humid montane regions of Puerto Rico. Digital elevation models and land use, geology, soils, and stream network coverages were used to evaluate 21 geomorphic, 10 stream channel, 9 relief, 7 geology, 4 climate, and 2 soil parameters for each watershed. To assess which parameters should be used for further investigation, a correlation analysis was used to determine the independence and collinearity among these parameters and their relationship with low flows. Multiple regression analyses using the selected parameters were then performed to develop the statistical models of low flows. The final models were selected in the basis of the Mallow Cp statistic, the adjusted R², the Press statistic, the degree of collinearity, and an analysis of the residuals. In the final models, drainage density, the ratio of length of tributaries to the length of the main channel, the percent of drainage area with northeast aspect, and the average weighted slope of the drainage were the most significant parameters. The final models had adjusted standard errors of 58.7 percent, 59.2 percent, and 48.6 percent for the 7d–10yr, 30d–10yr, and 7d–2yr low flows respectively. For comparison, the best model based on watershed parameters that can be easily measured without a GIS had an adjusted standard error of 82.8 percent.     

用分布式混合试验系统模拟结构的倒塌行为

采用分布式混合试验系统模拟四层钢结构框架在强震下的倒塌行为。变形集中的首层作为试验对象,而上部结构作为数值子结构。各子结构通过协调器满足界面上的平衡和协调条件,并被协调器的输入输出接口封装起来。采用柔性的试验方案,可以在当前有限控制精度的限制下,灵活地处理边界条件。试验结果与日本E-D efense振动台足尺试验结果进行了对比,得到了类似的倒塌机制,证明混合试验有能力进行结构倒塌模拟,而误差主要来自于模型简化。