丹江口水库浮游植物群落时空动态及其多样性指数

通过对丹江口水库2009～2010年的水质和浮游植物进行调查,分析了浮游植物群落的时空动态,利用典型对应分析法（CCA）研究了影响群落时空格局的环境因素,同时运用细胞密度及群落多样性指数等进行了水质综合评价.结果表明,浮游植物群落种类组成中硅藻门占51.08%,其次是蓝藻（18.39%）;浮游植物群落结构、密度及生物多...     

modifications of ultradian and orcadian rhythms of fetal heart rate after fetal-maternal adrenal gland suppression: A double blind study

In order to verify whether fetal and maternal adrenal gland suppression induces effects on fetal behaviour, triamcinolone was administered to five healthy pregnant women at 35 weeks of gestation. Five patients of the same gestational age were used as control. Fetal heart rate (FHR) and fetal movements were recorded continuously over 2-h interval by means of cardiotocography. After 3 weeks (38 weeks of gestation) the recordings were repeated without drug administration. Cortisol, adrenocorticotropin hormone, 17 β-estradiol and unconjugated estriol were measured at the same time every 2 h in maternal peripheral plasma. At 35 weeks we found a loss of circadian rhythms of the hormones investigated and modifications of ultradian and circadian patterns of FHR in the treated group with respect to the control. No differences in hormonal and biophysical parameters were found between the two groups after the end of treatment (38 weeks). These data suggest that the inhibition of fetal and maternal adrenal glands could cause modifications of FHR patterns.     

USE OF TOPOLOGICAL INFORMATION IN HYDROGRAPH ESTIMATION1

ABSTRACT: Discharge hydrographs computed from the theory of linear flow through topologically random channel networks are compared to actual discharge hydrographs for basins in semiarid regions of central Wyoming. The basins drained by the channel networks range in size from 0.69 to 10.8 square miles. Topological information consisting of stream-network magnitude and link -length distribution parameters are used in calibrating celerity values that ensure that the peak discharge and excess rainfall volume of the resulting computed hydrographs match the peak discharge and excess-rainfall volume of the actual hydrographs. Results indicate that, for a given peak discharge and excess-rainfall volume in a basin, the sensitivity of the calibrated celerity values to excess-rainfall duration is small if the ratio of excess-rainfall volume to peak discharge is at least 1.75 times the excess-rainfall duration.     

Interannual fluctuations in acoustic biomass estimates and in landings of small pelagic fish populations in relation to hydrology in the Strait of Sicily

The main results of research work carried out since 1998 with regard to the application of hydro-acoustic technologies for the evaluation of biomass and distribution of small pelagic fish species off the southern coast of Sicily are presented, taking into account information from hydrology and from ecology of the fish populations targeted. The biomass estimates and the population-density charts presented concern the two main species, i.e. sardine Sardina pilchardus (Walbaum, 1792) and anchovy Engraulis encrasicolus (Linnaeus, 1758). Both the sardine and anchovy populations experienced large inter-annual fluctuations, with biomass estimates ranging from 6000 to over 36,000 tonnes (t) (sardine) and from about 7000 to 23,000 t (anchovy). Acoustic estimates are largely consistent with landings recorded in Sciacca (the main fishing port for small pelagic species in the study area) during the year following the evaluation surveys. In addition, trends in sardine and anchovy biomass estimates appears to be negatively correlated with the mean sea surface temperature calculated over the time intervals January-September (sardine) and June-November (anchovy) of the preceding year, which correspond to larval and juvenile growth periods of target species. Observed patterns would suggest the importance of enrichment processes relevant to the survival of early stages, so determining recruitment success and finally higher population sizes.     

近五年中国自然灾害空间分布格局及其月动态变化研究

作者根据《中国减灾》所载１９９０～１９９４年月灾情记录，经统一编码和标准化处理，建立了以行政县为基本单元的数据库。进而对近五年来中国自然灾害空间分布及其月动态变化进行分析，并与１９４９～１９９０年中国自然灾害的平均状况进行对比。     

Soils Characteristics of The Bassendean and Spearwood Sands of the Gnangara Mound (Western Australia) and their Controls On Recharge, Water Level Patterns and Solutes of The Superficial Aquifer

The flow pathways of water in the soils of the Gnangara Mound are highly irregular and depend upon the moisture content, the repellency and preferential wettability potential of the soils. The occurrence of preferential flow is more evident in dry soils. As the soil wets during the rainy season, the water repellence and differential wettability decreases, the fingering and the preferential flow paths disappear. Most of the agricultural sites in the Spearwood Sands which showed more irregular flow than the Bassendean Sands are under continuous irrigation during cultivation season. As the repellency problems are chemically treated, it is therefore expected that the flow will be more uniform all the year round. Landuse is mainly responsible for variation in recharge rates; however, the hydraulic properties control aquifer response and water level pattern to a greater degree. Water levels in the mid 1970s were in a semi steady state. Since that time, a combination of increasing water use by pine plantations, heavy pumping from private boreholes in market gardens and private homes and intensive pumping from the Gnangara Mound for the metropolitan water supply have caused water levels to continually decline in the Superficial aquifer. Nitrate and phosphate concentrations in the regional Superficial aquifer are generally very low. None of the tested pesticides (atrazine, diazinon, dimethoate, endosulfan, fenamiphos, iprodione, malathion and chlorpyrifos) were detected in the groundwater samples collected from the monitoring bores.     

Interaction Between GSM Handset Helical Antenna and User's Head: Theoretical Analysis and Experimental Results

Summary The performance of a cellular phone commercial helical antenna at 900~MHz band, both in free space and in the presence of a human head phantom was studied. Numerical simulation of the phone model for the latter case has been performed giving 3D radiation diagrams. The effect of the phantom head on radiation diagrams is presented. The relative amount of the EM power absorbed in the head was obtained for several distances of the phone. Measurements were carried out in a RF anechoic chamber using standard horn antennas and a calibrated measuring system. Absolute radiation patterns of the antenna gain were obtained in the three principal planes. Significant reduction of the absorbed power could be achieved just by moving the phone 1 cm away from the head.     

一次低涡切变型连续性冰雹过程天气分析

对2004年7月13-20日西北地区东部出现的一次低涡切变型区域性冰雹天气过程,从其产生的大气环流背景和前期气候背景进行了讨论,并利用MICAPS提供的方法,对物理量场进行了初步分析,总结了其发生发展的客观规律。结果表明:形成这次连续性降雹的影响系统是500 hPa位于青藏高原东北侧到华北的低涡切变;深厚的不稳定层结和随高度增强的不稳定能量,是此次强对流发生的热力条件;有利的低层辐合与高层辐散的散度场是此次强对流发生的动力因子;随高度增强的上升运动为冰雹的形成提供了水汽条件。     

Chlorobenzenes in waterweeds from the Xijiang River （Guangdong section） of the Pearl River

The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes (CBs) in both water and waterweeds collected from 4 stations in the Xijiang River (Gangdong section) of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs (∑CBs) in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ∑ CBs in waterweeds ranged from 13.53×102 μg/g to 38.27×102μg/g dry weight (dw). There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs(DCBs), whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip (bioconcentration factor) of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was: Fengkai County ＜ Yunan County ＜Yun'an County ＜ Gaoyao County according to the ∑CBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River.