森林冠层上下湍流谱结构和耗散率

利用新型三维超声风速 /温度仪 ,根据在长白山原始森林冠层上下两个高度上测量的湍流资料 ,采用涡动相关法计算和分析了森林冠层上下湍流谱的结构、局地各向同性和耗散率 .结果表明 ,在惯性副区 ,归一化湍流谱遵从 - 23的指数规律 ;在森林冠层上 ,尽管谱的形状与均匀表面的一致 ,但是 ,大气湍流是非各向同性的 ;而在森林冠层内则是近似各向同性的 ;森林冠层上下湍流能量和热量耗散率比典型草原和牧场的结果大 ,揭示了森林粗糙表面在湍流输送过程中的动力扰动和对大涡的破碎作用     

Harmful algal blooms and eutrophication: ��strategies�� for nutrient uptake and growth outside the Redfield comfort zone

While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiometric proportion to the "Redfield ratio", and why this has important consequences for algal growth. Many types of harmful algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe some of the physiological mechanisms of different species to take up nutrients and to thrive under conditions of nutrient imbalance.     

Butterfly-plant interactions and body size patterns along an elevational gradient in the Manang region of central Nepal

Butterflies are widely studied due to their key ecosystem functions.For this reason,they are used in ecosystem assessment,formulating conservation plans and in raising the environmental awareness.Quantification of different factors affecting diversity of butterflies is important for their effective conservation.In this study,we investigated abiotic and biotic factors affecting species richness and community composition of butterflies along an elevational gradient in Manang region,central Nepal.We also tested if butterfly species follow the Bergmann’s rule.A total of 57 butterfly species belonging to 39 genera and 8 families were recorded in the study area.Out of a total of 127 plant species identified in the study region,only 67 plant species were visited by butterflies as nectar sources.Species richness of butterflies increased with increasing elevation.Species richness was significantly higher in places with shrubs compared to other places and also in autumn than in summer.Species richness of butterflies also depended on composition of plant species occurring at the localities.Butterfly species composition varied among sampling localities.It was also determined by habitat type,elevation,sampling time,plant species and interactions of elevation×time.The relationship between butterfly size and elevation was in the opposite direction than expected according to the Bergmann’s rule.In conclusion,protection of butterfly diversity can only be achieved by protecting different habitats across the diverse physiography of the region and different plant species,in particular herbs and shrubs.Our results do not support the Bergmann’s rule for butterflies along an elevational gradient in our region.     

The Mars oxidant experiment (MOx) for Mars '96

The MOx instrument was developed to characterize the reactive nature of the martian soil. The objectives of MOx were: (1) to measure the rate of degradation of organics in the martian environment; (2) to determine if the reactions seen by the Viking biology experiments were caused by a soil oxidant and measure the reactivity of the soil and atmosphere: (3) to monitor the degradation, when exposed to the martian environment, of materials of potential use in future missions; and, finally, (4) to develop technologies and approaches that can be part of future soil analysis instrumentation. The basic approach taken in the MOx instrument was to place a variety of materials composed as thin films in contact with the soil and monitor the physical and chemical changes that result. The optical reflectance of the thin films was the primary sensing-mode. Thin films of organic materials, metals, and semiconductors were prepared. Laboratory simulations demonstrated the response of thin films to active oxidants.     

Estuarine ecological risk based on hepatic histopathological indices from laboratory and in situ tested fish

Juvenile Senegalese soles were exposed through 28-day laboratory and field (in situ) bioassays to sediments from three sites of the Sado estuary (W Portugal): a reference and two contaminated by metallic and organic contaminants. Fish were surveyed for ten hepatic histopathological alterations divided by four distinct reaction patterns and integrated through the estimation of individual histopathological condition indices. Fish exposed to contaminated sediments sustained more damage, with especial respect to regressive changes like necrosis. However, differences were observed between laboratory- and field-exposed animals, with the latest, for instance, exhibiting more pronounced fatty degeneration and hepatocellular eosinophilic alteration. Also, some lesions in fish exposed to the reference sediment indicate that in both assays unaccounted variables produced experimental background noise, such as hyaline degeneration in laboratory-exposed fish. Still, the field assays yielded results that were found to better reflect the overall levels of contaminants and physico-chemical characteristics of the tested sediments.     

金刚石钻头性能的测试设备

测试新设计的现有的钻头、是发展钻进技术的基础。虽然现场测试是获得现场数据的唯一途径,但实验室测量可以在很宽范围的工作条件下最经济地获取实验数据。A。Ersoy和M.D Waller的文章,介绍了诺丁汉大学的一种在实验室测试岩石钻头的钻机。设计该钻机的目的是为了对各种不同岩石的众多钻头提供严格的测试平台。该钻机能够提供0－2000r/min的转速,最大4000kg的载荷和200Nm的扭矩。钻进可以在恒定进给或恒定载荷条件下进行。机器构架可以容纳高1m的试件。采用专门设计的软件,所有关键数据都能自动录入计算机,并自动形成报告书。软件可连续显示有效特征参量,如钻进比能量。常用功能还包括对实验室进程中钻头磨损的监控。     

中国辽宁早白垩世华夏翼龙（翼龙目：翼手龙亚目）一新种及古神翼龙科的系统分类

根据中国辽西早白垩世九佛堂组一几乎完整头骨及头后骨骼建立古神翼龙类一新种：具冠华夏翼龙。具冠华夏翼龙以前上颌骨上具有一斧状矩形突起为特征，该突起的短轴垂直于前上颌骨的前边缘，除了该突起之外，其他的头骨特征比如鼻眶前孔的前边缘和前上颌骨的前边缘之间的吻部宽度均与季氏华夏翼龙的相似。华夏翼龙和中国的另一个古神翼龙类中国翼龙与古神翼龙共享有一些独特的头骨特征，并且这3个属看起来彼此之间的关系要比与其他神龙类密切的多。中国的古神翼龙（中国翼龙和华夏翼龙）具有相对长的头骨和弱的头骨嵴，而且似乎要比头骨短高和具有大的头骨嵴的古神翼龙原始。Tupuxuarids（Tupuxuara和Thalassodromeus）经常和古神翼龙类被放在古神翼龙科中，