黎平山地气候特征

黎平山地占全县面积的８７．４％，丘陵占５．５％，所以山地气候成为黎平气候的一个重要特征。该文对黎平山地气候形成的背景及其若干特征进行了初步分析，为研究和开发及利用山地气候浆提供参考。     

Oxidative stress in the mussel Mytella guyanensis from polluted mangroves on Santa Catarina Island,Brazil

Digestive glands of the mangrove mussel Mytella guyanensis, collected at one non-polluted site (site 1) and two polluted sites (sites 2 and 3), were analysed for different antioxidant defenses, lipid peroxidation and DNA damage. Thiobarbituric acid-reactive substance (TBARS) and 8-oxo-7,8-dihydro-2'-deoxyguanosine levels were enhanced at the polluted sites. With the exception of superoxide dismutase, the activities of catalase and glutathione peroxidase were also higher at the polluted sites. Greater increases were observed in glutathione reductase, glutathione S-transferase and etoxyresorufine-O-deethylase activities at the polluted sites. Conversely, reduced glutathione content was higher at the control site. Trace metal contents in mussels collected at polluted sites were increased compared to the control site, and there were strong positive correlations between TBARS and Cu and Pb contents. M. guyanensis is routinely exposed to an oxidative stress condition at both polluted sites, and considering xenobiotic bioaccumulation in bivalve molluscs, the mangrove mussel represents an excellent bioindicator for environmental monitoring studies.     

丹寨气候资源分析及应用

利用丹寨县气象观测站1961～2000年的气象资料，对光、温、水及风能资源进行分析，重点分析热量资源和水资源。总的来看，丹寨气候资源比较丰富，其主要特征表现为：空中云水资源丰富，降水主要集中在4～8月上半月，雨量比较稳定，与作物需水高峰期相一致；夏季气候凉爽，日最高气温一般在32℃左右，非常适宜避暑；热量资源较丰富，作物生育期积温保证率高；日照与全国相比，虽处于低值区，但基本能保证作物进行光合作用。     

贵州黔东南州旅游气候资源分析

依据1961—2009年气象资料对黔东南州的气候特征进行分析,并计算出全州1-12月的特吉旺气候舒适度指数。结果表明：黔东南州各县近50 a年平均气温为14.6～18.5℃,气候温和,高温日数少;年降水量在1 028.6～1 432.9 mm之间,降雨多集中在4-8月,强降雨主要出现在夜间;年平均相对湿度78%～84%之间,季节变化不明显;日照适宜,冬季较少;大风日数少。综合各种气象因素分析,黔东南的气候资源有利于旅游业的发展。     

Radiative heating of interstellar grains falling toward the solar nebula: 1-D diffusion calculations

As the dense molecular cloud that was the precursor of our Solar System was collapsing to form a protosun and the surrounding solar-nebula accretion disk, infalling interstellar grains were heated much more effectively by radiation from the forming protosun than by radiation from the disk's accretion shock. Accordingly, we have estimated the temperatures experienced by these infalling grains using radiative diffusion calculations whose sole energy source is radiation from the protosun. Although the calculations are 1-dimensional, they make use of 2-D, cylindrically symmetric models of the density structure of a collapsing, rotating cloud. The temperature calculations also utilize recent models for the composition and radiative properties of interstellar grains (Pollack et al. 1994. Astrophys. J. 421, 615-639), thereby allowing us to estimate which grain species might have survived, intact, to the disk accretion shock and what accretion rates and molecular-cloud rotation rates aid that survival. Not surprisingly, we find that the large uncertainties in the free parameter values allow a wide range of grain-survival results: (1) For physically plausible high accretion rates or low rotation rates (which produce small accretion disks), all of the infalling grain species, even the refractory silicates and iron, will vaporize in the protosun's radiation field before reaching the disk accretion shock. (2) For equally plausible low accretion rates or high rotation rates (which produce large accretion disks), all non-ice species, even volatile organics, will survive intact to the disk accretion shock. These grain-survival conclusions are subject to several limitations which need to be addressed by future, more sophisticated radiative-transfer models. Nevertheless, our results can serve as useful inputs to models of the processing that interstellar grains undergo at the solar nebula's accretion shock, and thus help address the broader question of interstellar inheritance in the solar nebula and present Solar System. These results may also help constrain the size of the accretion disk: for example, if we require that the calculations produce partial survival of organic grains into the solar nebula, we infer that some material entered the disk intact at distances comparable to or greater than a few AU. Intriguingly, this is comparable to the heliocentric distance that separates the C-rich outer parts of the current Solar System from the C-poor inner regions.