Twin–twin transfusion syndrome—possible roles for doppler ultrasound and amniocentesis

A 29-year-old woman was referred for suspicion of twin-twin transfusion syndrome (TTTS). Several ultrasonographic and neonatal criteria of TTTS were encountered in this twin pregnancy. The peculiar observations in this case were, firstly, the demonstration of superficial anastomosis by Doppler ultrasound and, secondly, that one single therapeutic amniocentesis could have been sufficient to partially correct the progression of the syndrome, as after amniocentesis it was no longer possible to demonstrate the vascular communication. This observation suggests that superficial anastomoses could also have a role in the genesis of TTTS. Their effect could be monitored by Doppler ultrasound and could be more easily corrected by therapeutic amniocentesis.     

长三角农田轮作系统氨排放特征、转化机制和减排潜力

为评估长三角农田轮作系统氨排放特征和减排潜力,通过密闭室间歇通气法对典型农田轮作系统的氨排放水平进行同步对比观测,探讨不同条件下的氨排放影响因素和转化机制;通过整理近10年长三角地区农田氨排放实测系数,建立基于本地因子的长三角农田轮作系统氨排放时空分布清单,并获取了不同氨减排路径下的减排效果.结果 表明,常规稻麦轮作模...     

佛山市冬夏季非甲烷烃污染特征研究

2014年冬季和2015年夏季在佛山市采集了30个非甲烷烃(NMHCs)的样品,定量分析了多种化合物.结果表明,采样期间佛山市冬季和夏季NMHCS的浓度分别为122.30μg·m~(-3)和56.22μg·m~(-3).其中冬季和夏季NMHCs中浓度最高的5个物种由大到小依次为:甲苯(25.12μg·m~(-3))、间/对-二甲苯(13.76μg·m~(-3))、丙烷(9.17μg·m~(-3))、乙苯(7.25μg·m~(-3))、乙烯(6.77μg·m~(-3))和甲苯(6.18μg·m~(-3))、间/对-二甲苯(5.21μg·m~(-3))、邻-二甲苯(4.15μg·m~(-3))、β-蒎烯(3.75μg·m~(-3))、丙烷(3.29μg·m~(-3)).相比2008年,NMHCs有大幅度下降.冬季芳烃、烷烃、烯烃和炔烃所占比例分别为51.20%、34.70%、10.04%和4.05%;夏季芳烃、烷烃、烯烃和炔烃所占比例分别为43.93%、33.99%、19.20%和2.88%.因为NMHCs/NOx的冬、夏季值分别为0.90和1.88,表明采样期间佛山市大气臭氧峰值浓度都是受NMHCs控制,还应继续加强NMHCs的控制.佛山市NMHCs冬季和夏季的丙烯等效浓度和臭氧生成潜势分别为45.09μg·m~(-3)和40.64μg·m~(-3)、392.77μg·m~(-3)和207.77μg·m~(-3).间/对-二甲苯、甲苯和间/对-二甲苯、异戊二烯分别对冬季和夏季的臭氧生成潜势起到很重要的贡献.采样期间佛山市冬季和夏季的苯/甲苯的值为0.15和0.20,表明佛山市冬夏季NMHCs的主要来源是工业过程.相对2008年,本研究中异戊烷不属于佛山市NMHCs中浓度最高的5种污染物,说明佛山市在防止汽油挥发对环境造成影响方面的措施取得了明显成效.     

长三角背景地区秋冬季节大气气态总汞含量特征研究

利用Tekran 2537B大气汞分析仪于2009年9月15日～2009年12月17日对上海崇明岛大气气态总汞(TGM)进行了连续监测.监测期间,崇明地区气态总汞的平均含量为2.50 ng·m-3±1.50 ng·m-3,高于北半球背景浓度1.5～1.7 ng·m-3,月均浓度9月<10月<11月<12月.9～12月,崇明地区气态总汞含量的日变化规律为上午08:00～10:00出现峰值,白天气态总汞浓度水平与夜间基本一致.崇明地区气态总汞含量和一氧化碳含量具有较好的相关性,表明崇明地区大气汞主要来自火电厂和工业锅炉的燃煤排放.从风向和后向轨迹模型分析的结果来看,崇明岛的大气汞主要来自西部的大陆地区,尤其是位于崇明西北部的江苏、山东等地.9月和10月盛行来自海面的东风,因而气态总汞含量较低,11月和12月盛行来自大陆工业区的西北风,导致崇明气态总汞含量较高.     

广西冬季冻害发生规律及影响因子研究

利用广西88个观测站1959-2000年冬季（12-2月）逐日极端最低气温资料，根据冬季冻害的标准，分析了广西冬季冻害的发生规律和地域分布特征，并采用数理统计方法，分析了北半球500hPa月平均高度场和太平洋海温场与广西冬季冻害的关系。     

How effective are current household recycling policies? Results from a national survey of U.S. households

This paper analyzes a unique dataset collected during a 2006 national survey of U.S. households to explore the effectiveness of common household recycling policies for metals, glass, and plastics: curbside recycling, drop-off recycling, deposit–refund systems (bottle bills), and marginal pricing for household waste. After estimating either generalized ordered logit or multinomial logit models, we find that the most important determinants of household recycling are people's attitudes toward recycling. Our results also suggest that omitting internal variables (perceived recycling obstacles and benefits as well as moral considerations) may bias policy coefficients. Socio-economic variables are typically not statistically significant, with the exceptions of young adults and of African Americans who tend to recycle less than others. Policies with the largest odds ratios are curbside recycling (which is further strengthened if recycling is mandatory), followed by the presence of drop-off collection centers nearby. Bottle bills are also statistically significant but their odds ratios are smaller, possibly because refunds are relatively small and typically do not change for years. Finally, marginal pricing appears to have a limited impact on recycling. These results suggest avenues for improving household recycling at a time when recycling rates appear to be plateauing.     

湖北省60年代以来平均气温变化趋势初探

计算了湖北省７２个气象台年,季,月平均气温在１９６１－１９９５年间的气候倾向率,分析其时空分布特征发现：１）全省大部春季,秋季,年的ｂ值小,夏屯,冬季的ｂ值;２）冬季或１２－２、４月的ｂ值多为正,夏季或３、６－８月的ｂ值为多负,且有一定显著程度;３）夏季变凉冬季变暖,春季前后的变化大,秋季前后变化小;（４）升温中心多在江汉平原和鄂东南,降温中心多在鄂西山区尤其是鄂西北;５）大、中城市的相对热岛效应     

北京市核心区冬春季大气离子沉降量特征及来源解析

近年来生态环境部和北京市不断加严降尘量控制指标,为了掌握降尘量中离子沉降量特征及其来源,采用过滤法和离子色谱法分别测定北京市核心区冬春季降尘量及离子沉降量,采用PMF模型开展离子沉降量来源解析.结果表明：(1)离子沉降量及其在降尘量中占比平均值分别为0.87 t·(km²·30 d)^-1和14.2%,工作日降尘量和离子沉降量分别是休息日的1.3倍和0.7倍.(2)离子沉降量与降水量、相对湿度、温度和平均风速的线性方程可决系数分别为0.54、 0.16、 0.15和0.02,离子沉降量与PM_2.5浓度和降尘量的线性方程可决系数分别为0.26和0.17,控制PM_2.5浓度对控制离子沉降量非常重要.(3)离子沉降量中阴、阳离子分别占61.6%和38.4%,SO^2-₄、 NO^-₃和NH⁺₄合计占60.6%;阴阳离子电荷沉降量比值为0.70,降尘呈碱性;离子沉降量中ρ(NO     

Revealing the economic channels of natural impacts: an extended input–output subsystems application to GHG gases and water use

While a small set of economic activities generates most of the direct environmental burdens, the complexity of connections within an economic system requires consideration of the effects caused by the interdependences between its different agents. To date, however, the input–output (I–O) subsystems literature has been limited to uncovering the intersectoral linkages of direct and indirect environmental impacts within an economy and the connections between sectors and private consumption have thus not attracted much attention. This paper proposes an I–O subsystems model that endogenously incorporates not only production sectors but also household consumption to capture the entire channel of environmental impacts. The empirical application focuses on carbon dioxide equivalent (CO₂-eq.) emissions and water use associated with production sectors and households defined in the I–O table for a Spanish region, Extremadura. The results highlight the key role of the effects induced by private consumption on the environmental burdens of services.