Effects Of Adverse Conditions Research Articles

Performance deterioration of asphalt mixture exposed to salt-water-temperature-ultraviolet coupling effect

ABSTRACT The intense ultraviolet radiation and large amount of saline-alkali soil in the Golmud region of Province, China, have deteriorated the performance of asphalt pavement. Given the effect of adverse conditions in this area, this paper investigated the collective and interaction effects of salt chemicals, air temperature, and ultraviolet radiation on asphalt and asphalt mixture through laboratory experiments under controlled conditions. In particular, using different concentrations of Na2SO4 and NaCl solutions, simulated salt chemicals for asphalt and asphalt mixture performance impact. The mechanism of performance deterioration of the asphalt mixture suffered from salt attack was explored. The results show that the original asphalt's storage and loss modulus are higher than the modified asphalt at different temperatures with the multi-factors effect. In addition, the modified asphalt's phase angle is 5%∼10% higher than the original asphalt below −2°C. At the same time, strength loss rates of asphalt mixture increase with the cycles and solution concentration, varying from 20%−40%. Wet-dry cycles and the concentration of salt solution are positively correlated with the deterioration of asphalt mixture strength. This research provides the durability prediction and the more reasonable composition design of the asphalt mixture applied in salt enrichment regions.

Lucky women in unlucky cohorts: Gender differences in the effects of initial labor market conditions in Latin America

This paper assesses gender differences in the effects of adverse conditions at labor-market entry in a developing region. Using harmonized microdata from national household surveys for 15 Latin American countries, we build a synthetic panel of cohorts that potentially transition from school to work and observe their labor market outcomes 10 years later. We find that men who faced higher unemployment rates at ages 18–20 suffer a negative effect on employment at ages 27–30. In contrast, women from those same unlucky cohorts have higher employment rates and earnings. Our results are consistent with women acting as secondary workers in downturns. We also find that initial labor market conditions correlate with the role played by women within the household and to perceptions about gender roles later in life. Such higher empowerment could be a result of increased female labor participation and at the same time might act as a mechanism underlying the persistence of the positive effects on female labor outcomes.

Flow-through isolation of human first trimester umbilical cord endothelial cells

Human umbilical vein and artery endothelial cells (HUVEC; HUAEC), placental endothelial cells (fpAEC), and endothelial colony-forming cells (ECFC) from cord blood are a widely used model for researching placental vascular development, fetal and placental endothelial function, and the effect of adverse conditions in pregnancy thereon. However, placental vascular development and angiogenesis start in the first weeks of gestation, and adverse conditions in pregnancy may also affect endothelial function before term, suggesting that endothelial cells from early pregnancy may respond differently. Thus, we established a novel, gentle flow-through method to isolate pure human umbilical endothelial cells from first trimester (FTUEC). FTUEC were characterized and their phenotype was compared to the umbilical endothelium in situ as well as to other fetal endothelial cell models from term of gestation, i.e. HUVEC, fpAEC, ECFC. FTUEC possess a CD34-positive, juvenile endothelial phenotype, and can be expanded and passaged. We regard FTUEC as a valuable tool to study developmental processes as well as the effect of adverse insults in pregnancy in vitro.

Carry‐over effects of environmental stochasticity of the California Current on body condition and wing length of breeding Black‐vented Shearwaters (Puffinus opisthomelas)

Recent climatic variation has led to a change in size or mass in some species. The Black‐vented Shearwater Puffinus opisthomelas is endemic to the California Current System, a highly variable system, giving us cues as to the effects of interannual variability on predators. Here, we report the results of a comparison of biometrics measurement in the short term, 4 years, with different environmental conditions. We found that environmental variability has a direct effect on the body condition of the species, affecting not only body mass but also wing length, with shorter wings as a carry‐over effect of adverse conditions.

Isolating the direct effects of adverse developmental conditions on in vivo cardiovascular function at adulthood: the avian model.

It is now well accepted that exposure to adverse environmental conditions in utero can predispose a fetus to disease later in life. Using an avian model to study the programming of disease has a unique advantage as it allows isolation of the direct effects of adverse conditions on fetal physiology, without any confounding effects via the mother or placenta. However, experiments in avian models are limited by the lack of well-established surgical protocols for the adult bird, which we have established in this study. Surgery was performed on seven young adult Bovan Brown chickens (body weight 1617±214 g, mean±s.d.) in order to instrument them with femoral arterial and venous catheters and a femoral arterial flow probe. Isoflurane and lidocaine were both found to have depressive effects on chicken cardiovascular function. Optimised methods of anaesthesia, intraoperative monitoring, surgical approach, postoperative care, and experimentation are described. Chickens recovered rapidly from surgery without significant blood gas perturbation, and basal in vivo cardiovascular studies were performed following 5 days of recovery. These techniques allow detailed investigation of avian cardiometabolic function, permitting determination of the consequences in later life of direct environmental insults to fetal physiology, isolated from additional effects on maternal physiology and/or placental endocrinology.

Relative importance off environmental variables in determining the growth off nestling Tree Swallows Tachycineta bicolor

Unpredictable, short‐term changes in environmental conditions associated with weather patterns have severe impacts on the reproductive success of Tree Swallows Tachycineta bicolor, as well as other aerial insectivores. We examined the effects of day‐to‐day environmental variation on the growth of nestling Tree Swallows. Using path analysis, we compared the relative importance of changes in food availability, ambient temperature and wind speed on changes in mass and feather length over four years at our study site near Ithaca, New York. Changes in environmental conditions explained a significant amount of the variation in nestling growth, with daily high temperature having the greatest influence for nestlings younger than five days. Both food supply and temperature had significant direct effects on growth of nestlings older than nine days, with temperature also having a significant indirect effect through its influence on food availability. For both young and old chicks, mass gains were smaller for chicks hatched later in the season. Environmental conditions also explained a significant amount of the linear growth of the ninth primary feather in one of two years, with food supply showing the most consistent positive effect. Environmental conditions several days prior to the measurements significantly influenced feather growth, indicating that the effects of adverse conditions are spread out over several days of feather growth, but this effect was not seen for change in mass.

Postmortem Diagnosis of Meningococcemia by Detection of Capsular Polysaccharides

Detection of specific meningococcal capsular polysaccharide (CPS) in postmortem blood permits rapid diagnosis of meningococcemia and differentiation from pneumococcemia and septicemia caused by Haemophilus influenzae Type b. We present studies validating application of latex agglutination assay for CPS on blood samples collected at autopsy, delineate the circumstances when CPS testing is indicated, and illustrate the usefulness of this procedure by several recent cases. Blood samples from victims dying of injury or disease other than infection were examined to determine whether the postmortem interval, bacterial contamination, anticoagulants, or delay in testing would result in false positive assays. Series 1 samples, collected so as to minimize bacterial contamination, were immediately submitted for assay. Series 2 evaluated the effect of adverse conditions of collection, anticoagulation, and prolonged sample storage. Despite extended postmortem intervals of up to 14 days, heavy bacterial contamination, prolonged storage at 4 degrees C, deep hemolysis, and presence of anticoagulants, false positive assays were seldom observed.