Role of juvenile hormone biosynthesis in dominance status and reproduction of the bumblebee,Bombus terrestris

Summary In Bombus terrestris females, dominant status is correlated with high levels of juvenile hormone (JH) biosynthesis and rapid oöcyte maturation. Queenright workers, which are inhibited by the dominant queen, complete the cycle of oöcyte maturation while exhibiting a continuous low rate of JH production, but their egglaying is inhibited. Measurements in foundress queens suggest that the low JH titer during oögenesis is probably not responsible for the inhibition of egg-laying. Queenless workers, kept individually, are not activated either for JH production or oöcyte maturation. In groups of three queenless workers, a dominance order becomes established and high rates of JH synthesis are observed in the dominant egg-laying workers, with low rates in subordinated workers. In groups of founder queens, also, a dominance order becomes established and results in a reduced rate of JH production in subordinated females. Correspondence to: F. Couillaud     

Prenatal interventions for fetal lung lesions

The widespread availability of high resolution ultrasound equipment and almost universal routine anatomy scanning in all pregnant women in the developed world has lead to increased detection of abnormalities in the fetal thorax. Already in the 1980s, large pleural effusions and significant macrocystic lesions in the fetus were easily detected on ultrasound. However, smaller lung tumours were often missed. Nowadays, fetal medicine centres receive many referrals for evaluation of fetal lung lesions, of which the most common are congenital cystic adenomatoid malformation and bronchopulmonary sequestration. Almost invariably, both the parents and the referring physicians experience anxiety after detection of large lung masses in the fetus. However, the vast majority of the currently detected fetal lung lesions have an excellent prognosis without the need for prenatal intervention. In the small group of fetuses in which the prognosis is poor, almost exclusively those with concomitant fetal hydrops and cardiac failure, several options for fetal therapy exist, often with a more than 50% survival rate. Indications, techniques, complications and outcomes of these interventions will be described in this review. Copyright © 2011 John Wiley & Sons, Ltd.     

河北张家口地区雹灾区划研究

使用雹灾汇报资料,对本区的雹灾受灾频率、重灾频率和成灾面积比的分布做了区划分析。结果显示：受灾频率较大的地区基本与本区的坝头地带、坝上西部及复杂山地配合;较小的地区是海拔最低的洋河谷地。重灾频率和成灾面积比的分布与受灾频率基本相反。分析原因,主要是雹块大小与海拔高度呈反相关以及生长期的差异。     

How many samples are required? Evaluating a model for verification of carbon sequestration in a hybrid poplar buffer strip

A model is developed to predict annual and total above-ground carbon storage within a hybrid poplar stream buffer. The regression model predicts tree wet weight based upon circumference at breast-height (137 cm) with an r-square value of 0.9922. Carbon storage in above-ground biomass is estimated to be 3.57 to 3.71 metric tons per hectare, with a measured annual increment of 0.92 to 1.37 metric ton per hectare per year. The variability of carbon storage within this biological system, including soil organic matter, is explored, and the number of samples required to achieve a desired level of statistical certainty are predicted. As has been investigated previously for other biological systems (Garten and Wullschleger, 1999), the study shows that a prohibitively large number of samples must be taken in order to achieve high degrees of certainty about mean carbon storage values. The study also shows, however, that mean values with somewhat greater uncertainties can easily be achieved with much smaller sample sizes. Thus carbon sequestration verification might be accomplished cost-effectively if the degree of certainty required is not unrealistically high for highly variable natural systems.     

The Potential of Soil Carbon Sequestration Through Improved Management Practices in Norway

The study was conducted to assess the potential of Norwegian agricultural ecosystems to sequester carbon (C) based on the data from some long-term agronomic and land use experiments. The total emission of CO₂ in Norway in 1998 was 41.4 million metric ton (MMT), of which agriculture contributed only 0.157 MMT, or <0.4% of the total emissions. With regards to methane (CH₄) and nitrous oxide (N₂O) gases, however, agricultural activities contributed 32.5% and 51.3% of their respective emissions in Norway. The soil organic carbon (SOC) losses associated with accelerated soil erosion in Norway are estimated at 0.475 MMTC yr^–1. Land use changes and soil/crop management practices with potential for SOC sequestration include conservation tillage methods, judicious use of fertilizers and manures, use of crop residues, diverse crop rotations, and erosion control measures. The potential for SOC sequestration is 0.146 MMTC yr^–1 for adopting conservation tillage, 0.011–0.035 MMTC yr^–1 for crop residue management, 0.026 MMTC yr^–1 for judicious use of mineral fertilizer, 0.016–0.135 MMTC yr^–1 for manure application, and 0.036 MMTC yr^–1 for adopting crop rotations. The overall potential of these practices for SOC sequestration ranges from 0.591 to 1.022 MMTC yr^–1 with an average value of 0.806 MMTC yr^–1. Of the total potential, 59% is due to adoption of erosion control measures, 5.8% to restoration of peat lands, 21% to conversion to conservation tillage and residue management, and 14% to adoption of improved cropping systems. Enhancing SOC sequestration and improving soil quality, through adoption of judicious land use and improved system of soil and crop management, are prudent strategies for sustainable management of soil, water and environment resources.Readers should send their comments on this paper to: bhaskarn ath@aol.com within 3 months of publication of this issue.     

资源驱动型旅游地中心城市形象研究——以黄山市屯溪区为例

资源驱动型旅游地中心城市是我国普遍存在的一种旅游城市类型，但对这类城市形象的研究相对较少。以黄山市屯溪区为例，在感知形象测度的基础上，利用定性与定量方法论结合分析其感知形象现状和问题，并提出解决方案，总结出该类型城市在形象建设中应当注意的四对矛盾。     

三江并流带旅游地质资源环境现状及保护

地质资源是一种重要的旅游资源，有必要对其开发，但由于旅游地质资源环境自身的脆弱性，关联性，以及人类活动对其不合理的开发和利用，都会使其毁于一旦。笔者以三江并流带旅游地质资源的开发为例，分析了三江并流带开发中旅游地质资源环境的现状、存在问题及其影响因素，并提出了旅游地质资源环境保护的建议、对策。     

DTH-单体液压支柱推护器的研制及应用

分析了回采工作面回柱放顶作业中防护措施的不足,介绍了DTH推护器的结构和现场应用效果.     

倾斜采空场的空场处理机理分析

在变荷载的条件下 ,推导了倾斜采空场的空场处理前、后正应力的分布。求解了切槽放顶的最佳位置。结果表明 ,倾角为 4 0°,标高为 971.5 m是切槽放顶的最佳位置。松散体接顶后 ,下部水平荷载降低 ,钢砼隔离墙较深部水平承受压力增加 ,顶板应力向三维状态变化 ,有利于安全采矿     

溶剂萃取法对苯甲酸废水预处理的研究

甲苯液相空气氧化法生产苯甲酸废水的成分复杂,属生物难降解体系,COD_Cr值高达20000～100000mg/L.本研究分别采用磷酸三丁酯、三烷基胺、三烷基氧膦为络合剂,正辛醇为助溶剂,煤油为稀释剂,通过萃取-反萃的方式,对苯甲酸废水进行处理.结果表明,多级错流萃取能有效地回收溶质苯甲酸,将原废水的COD_Cr值降低至1/6,使之满足其它末端处理的要求,而且反萃工艺简单易行,可生产苯甲酸盐,溶剂可重复使用.