Second-trimester echogenic small bowel: An increased risk for adverse perinatal outcome

2267 singleton fetuses who had one ultrasound examination between 15 and 21 weeks' gestation were prospectively evaluated for echogenic small bowel. Thirty-two cases of echogenic small bowel were detected—a prevalence of 1·4 per cent. Echogenic fetal small bowel was divided into two grades: grade 1, where the small bowel was more echogenic than the liver; and grade 2, where the small bowel had the echogenicity of bone. In contrast to 19/23 fetuses with grade 1 small bowel echogenicity, only 2/9 fetuses with grade 2 echogenic bowel had a normal pregnancy outcome (Fisher's exact test; P⩽0·01). Complications associated with second-trimester echogenic small bowel included in utero cytomegalovirus infection, second-trimester growth restriction, intrauterine fetal demise, and chromosomal abnormalities. Second-trimester fetal echogenic small bowel is associated with an increased risk of an adverse outcome. The prevalence of perinatal and neonatal complications is significantly greater when small bowel echogenicity approaches that of bone.     

化学沉淀法除去废水中的氨氮及其反应的探讨

研究了化学沉淀法处理含氨氮废水，实验研究了不同操作条件，如溶液ｐＨ值、沉淀剂种类和配比、废水中的初始氨浓度等对氨的处理效率的影响，在适宜的操作条件下，可除去废水中的氨高达９９％，处理后残液中氨浓度小于１ｍｇ／Ｌ（１ｐｐｍ），探讨了化学沉淀反应过程的机理。     

Differential aggressiveness between fire salamander (<Emphasis Type="Italic">Salamandra infraimmaculata</Emphasis>) larvae covaries with their genetic similarity

Responding differentially to kin and non-kin is known to be adaptive in many species. One example is the inclusive fitness benefits of reducing aggression toward closer relatives. Little is known, however, about the ability of animals to assess differential degrees of genetic relatedness and to respond accordingly with differential levels of aggression. In the present study, we tested whether aggressiveness between body mass-matched pairs of fire salamander (Salamandra infraimmaculata) larvae covaried with the genetic similarity between them. We quantified aggressiveness at three levels of genetic similarity by selecting pairs within and across pools from recently genotyped populations. We also assessed aggression between pairs of siblings. Aggression and associated injuries decreased as genetic similarity increased across the groups. These findings suggest that cannibalistic salamanders can assess their degree of genetic relatedness to conspecifics and vary their behavioral responses depending on the degree of similarity between them along a genetic relatedness continuum.     

Understanding Managers’ Views of Global Environmental Risk

This research investigated managers’ views of two global environmental risks: climate change and loss of biodiversity. The intent was to understand why different managers place varying levels of attention and priority on these issues. The data came from in-depth interviews with 28 senior corporate managers across Canada and a range of sectors, although most were employed in the energy sector. Approximately half had direct environmental responsibilities and half had other management duties. Grounded theory was used to collect and analyze the data. From the results, a theoretical framework was constructed to explain important factors that can influence managers’ mental models of environmental risk. Four factors relevant to managers’ appraisal of the threat of environmental risk include: (1) salience, (2) intrinsic value of nature, (3) knowledge, and (4) perceived resilience of nature. In addition, four factors relevant to managers’ view of the appeal of a particular response strategy were: (1) avoidability, (2) perceived costs and benefits, (3) fairness and equity, and (4) effectiveness. The time horizon for decision making was seen as being important in both portions of the mental model.     

Sorption of atmospheric ammonia by soil and perennial grass downwind from two large cattle feedlots

Livestock manure in feedlots releases ammonia (NH3), which can be sorbed by nearby soil and plants. Ammonia sorption by soil and its effects on soil and perennial grass N contents downwind from two large cattle feedlots in Alberta, Canada were investigated from June to October 2002. Atmospheric NH3 sorption was measured weekly by exposing air-dried soil at sampling points downwind along 1700-m transects. The amount of NH3 sorbed by soil was 2.60 to 3.16 kg N ha(-1) wk(-1) near the source, declining to about 0.25 kg N ha(-1) wk(-1) 1700 m downwind, reflecting diminishing atmospheric NH3 concentrations. Ammonia sorption at a control site away from NH3 sources was much lower: 0.085 kg N ha(-1) wk(-1). Based on these rates, about 19% of emitted NH3 is sorbed by soil within 1700 m downwind of feedlots. Field soil and grass samples from the transect lines were analyzed for total N (TN) and KCl-extractable N content (soil only). Nitrate N content in field soil followed a trend similar to that of atmospheric NH3 sorption. Soil TN contents, because of high background levels, showed no clear pattern. The TN content of grass, downwind of the newer feedlot, followed a pattern similar to that of NH3 sorption; downwind of the older feedlot, grass TN was correlated to soil TN. Our results suggest that atmospheric NH3 from livestock operations can contribute N to local soil and vegetation, and may need to be considered when determining fertilizer rates and assessing environmental impact.     

A comparison of fine particle and aerosol strong acidity at the interface zone (1540 m) and within (452 m) the planetary boundary layer of the Great Gulf and Presidential-Dry River Class I Wildernesses on the Presidential Range,New Hampshire USA

Mount Washington, NH in the White Mountain National Forest, is flanked to the north-northeast and south by two Class I Wilderness areas, the Great Gulf and Presidential Range-Dry River Wildernesses, respectively. The Clean Air Act protects Class I Area natural resource values from air pollution. Aerosol sulfate, a fine particulate component that is often transported long distances, is a known contributor to visibility degradation and acidic deposition. We examined summertime fine particulate aerosol mass and sulfate, strong acidity and ammonium concentrations from 1988 to 2007 on Mount Washington at two elevations, 452 and 1540 m (msl). The former site is often within, and the latter at the interface of, the planetary boundary layer. Comparisons of sampling interval durations (10 and 24 h) and site vs. site are made. We also examine the extent to which aerosol sulfate is neutralized.Ten hour (daytime) compared to 24 h samples have higher mass and aerosol sulfate concentrations, however paired samples are well correlated. Fine mass concentrations compared between the 452 m and 1540 m sites (standard temperature and pressure corrected) show a weak positive linear relationship with the later being approximately 32% lower. We attribute the lack of a strong correlation to the facts that the 1540 m site is commonly at the interface of and even above the regional planetary boundary layer in summer and that it can intercept different air masses relative to the 452 m site. Sulfate is ～18% lower at the higher elevation site, but comprises a greater percentage of total fine mass; 42% compared to 37% for the high and low elevation site, respectively. Aerosol strong acidity was found to increase with increasing sulfate concentrations at both sites. Further the ratio of hydrogen to sulfate ion was greater in 24 h than 10 h samples at the higher elevation site likely due to overnight transport of fresh acidic aerosols.     

Sensitivity of Native Desert Vegetation To SO2 and to SO2 and NO2 Combined

Interest in air pollution injury to native vegetation has been generated with the construction and planned construction of large coal-fired power plants near the coal reserves in the southwest desert areas of the United States. Since information on the effects of SO₂ on these native species was not available in the literature, fumigation studies were conducted with portable chambers placed over native species in the field with SO₂ and SO₂ + NO₂. Pollutant concentrations were measured and controlled with instruments located in a mobile laboratory. Each fumigation was of two hours duration and the concentration ranged from 0.5 to 11 ppm SO₂ and from 0.1 to 5 ppm NO₂. Concentrations of SO₂ above 2 ppm were required to cause injury to all but a few of the 87 species studied. Many of the native desert species proved to be highly resistant to injury from these gases.