煤巷迎头深部瓦斯赋存规律的实验数据分析

根据近两年来对不同矿区、不同煤层的不同煤巷掘进工作面迎头深部瓦斯赋存量以及突出预测数据的现场及实验室测定结果,得出一个在动态应力场作用下的工作面(掘进、回采)迎头深部瓦斯赋存量随深度变化的一个驼峰曲线,即工作面迎头深部的瓦斯赋存量受采动的影响而在不太深的位置处(如5~10m)会产生一个赋存峰,随着深度的增加瓦斯赋存量并非随之一直增大,其分布特征也与现有认识不尽相同。该测定结果为解释和研究工作面迎头深部的瓦斯运移、应力场分布、突出预测等提供了一个现场数据结论,为煤岩体流变模型的建立提供了相应的参考,也提出针对测定结果的疑问。     

垃圾填埋场防渗浆材对污染物的阻滞规律

基于自行研制的膨润土-水泥-粉煤灰(BCF)浆材和柔壁渗透仪,采用人工配制的重金属离子溶液和有机溶液,以及取自垃圾填埋场的渗沥液对不同高度浆材结石体进行了渗滤试验,试验证明:由于渗滤沉积作用和吸附滞留作用,浆材结石体对Hg、As、Pb、Cr、Cd等重金属污染物的95%,苯酚、苯胺、萘和邻苯二甲酸二丁酯等有机污染物的96%,以及NH4+-N、TN、TP、COD、BOD5等垃圾渗沥液中污染物的60%阻滞在开始渗滤的30 mm范围内,而且随着试样高度增加,对各种污染物的阻滞率基本呈现增大的趋势,并有一定的规律可循。     

汶川8.0级地震触发地质灾害发育分布规律研究

汶川8.0级地震共触发地质灾害13 759处,灾区39个县(市、区)的地质灾害发育密度达14.02处/100 km2。该文采用以上数据,探讨了地震地质灾害的区域性分布规律,着重分析了地震地质灾害与地震烈度、地层岩性、地形坡度及海拔高程等影响因素的关系,得出以下认识:1研究区地震地质灾害主要分布于发震断裂两侧30 km范围内,在区域上表现出沿龙门山中央断裂呈"带状"分布、沿水系呈"线状"或"串状"分布的特征;2地震地质灾害发生的斜坡部位与微地貌形态有着密切的关系,地震地质灾害多沿山脊线或分水岭部位高位分布;3地震地质灾害的发育程度与地震烈度呈正相关关系,地质灾害的发育密度,随着地震烈度等级的降低而降低;4地震地质灾害主要发育在较软岩岩组和坚硬岩岩组内,在地震力作用下,软岩岩组内更容易引发滑坡灾害,崩塌多发育在坚硬岩组内;5在海拔1 000~1 500 m,斜坡坡度30°~50°区域范围内是地质灾害集中发育区,不同坡度范围内,地震地质灾害表现出不同的优势发育类型。     

Discounting and relative consumption

We analyze optimal social discount rates when people derive utility from relative consumption, i.e. their own consumption level relative to the consumption level of others. We compare the social, private, and conventional Ramsey rates. Assuming a positive growth rate, we find that (1) the social discount rate exceeds the private discount rate if the importance of relative consumption increases with consumption, and that (2) the social discount rate is lower than the Ramsey rate given quasi-concavity in own and others’ consumption and risk aversion with respect to others’ consumption. Numerical calculations demonstrate that the latter difference may be substantial and have important implications for long run environmental issues such as global warming.     

近50年内蒙古山洪灾害的规律及成因

在全面系统地统计分析近50年的内蒙古山洪灾害和降水资料的基础上,得出了内蒙古山洪灾害发生的时空分布特征周期变化规律和影响因子。研究表明内蒙古山洪灾害具有时间序列周期性和单峰型正态分布特征,主要发生期为每年7,8月份,7月中旬是山洪灾害的高峰期;每日13-15时是山洪灾害的高发时段。山洪灾害的空间变化受暴雨空间变化和山区、丘陵区分布的影响明显,在东西部地区各有一个中心。山洪灾害具有暴发突然、水量集中、影响范围大、经历时间短、灾害损失严重等特点。山洪灾害的发生是高强度暴雨与复杂的地质构造共同作用的结果,其中,全球气候变暖是山洪灾害增多的主导因素;生态环境和土地资源的破坏对山洪灾害的发生起到了推波助澜的作用。     

河北省沿海风暴潮的发生规律研究

风暴潮是河北省沿海最主要的灾害之一。本文收集整理了最近２０４４年的史料，分析了河北省风暴潮的成因，讨论了风暴潮的时空分布特征、危害程度及区域评价，提出了河北省风暴潮的预警要点。     

Relative importance of multiple plumage ornaments as status signals in golden whistlers (<Emphasis Type="Italic">Pachycephala pectoralis</Emphasis>)

Status signals are traits that advertise an individual’s competitive abilities to conspecifics during aggressive disputes. Most studies of status signals in birds have focussed on melanin-based plumage signals, but recent research shows that carotenoid-based signals may also play a role in aggressive signaling. We assessed the relative importance of melanin- and carotenoid-based plumage patches as agonistic signals in a small passerine, the golden whistler (Pachycephala pectoralis). Display signals in male golden whistlers include an unpigmented white throat patch, a carotenoid-based yellow breast and nape band, and a melanin-based black chin-stripe. We found that only the white throat patch was correlated with contest-related attributes. Males possessing large throat patches defended larger territories and commenced breeding earlier. When caged males with either experimentally reduced, or unmanipulated throat patches were presented to conspecifics, those with experimentally reduced patches attracted less aggression from male subjects. Focal males also responded faster to caged males with throat patches similar in size to their own, suggesting that they may assess relative throat patch size before engaging in aggressive encounters. Females did not discriminate between “reduced” or “control” treatments. Our data strongly suggest that only the unpigmented throat patch functions as a status signal. As this signal is unlikely to have significant development costs, honesty may be maintained through social costs.     

Differences in reproductive success between laboratory and wild-derived golden hamsters (Mesocricetus auratus) as a consequence of inbreeding

All laboratory golden hamsters (Mesocricetus auratus) originated from a sibling pairing back in 1930. Due to this extreme founder event, domestic golden hamsters are presumed to be one of the most bottlenecked animal populations. Nevertheless, domestic hamsters show no obvious signs of inbreeding depression in commonly used breeding stocks. To explore the existence of potentially masked inbreeding effects, we compared the reproductive success of laboratory (lab) and wild-derived (wild) golden hamsters. We allowed oestrus females to mate consecutively with lab and wild males. The resulting offspring was genotyped using microsatellites to assess paternity. Finally, we compared male reproductive success to genetic variability, sexual behaviour and different sperm characteristics. Both hamster strains exhibited the expected large difference in genetic diversity (H _wild =0.712±0.062 vs H _lab =0.007±0.007. The reproductive success of wild males dramatically exceeded that of lab males (87% of pups were sired by wild males). Sexual behaviour of wild and lab males only varied in the number of long intromissions (intromissions without ejaculation at the end of the mating). No significant differences were observed in relation to mounting, ejaculation and intromission. There were also no apparent differences in sperm motility, velocity and density or testis histology between wild and lab hamsters. We conclude that the reduced reproductive success of lab males represents a hidden inbreeding effect, although its precise physiological cause remains unclear. These results provide first evidence for a major fitness disadvantage in captive golden hamsters.     

Implications of sea level rise for coastal dune habitat conservation in Wales,UK

The potential impact of future sea level rise and climate change on 15 Welsh coastal dune systems has been investigated. Historical Trend Analysis was undertaken using Ordnance Survey maps to quantify past shoreline change and to permit extrapolation of past trends to predict possible future shoreline positions by 2080–2100. Predictions were also made using the Bruun Rule relationship between sea level rise and shoreline response and an integrated method of assessment, Expert Geomorphological Assessment (EGA), which provides a ‘best estimate’ of future coastline change, taking into account such factors as geological constraints, the nature of past, present and future environmental forcing factors, and known coastal process–response relationships. The majority of the 15 systems investigated experienced a net increase in dune area over the last 100–120 years. Only one (Whiteford Burrows) experienced significant net area loss (>5 ha). EGA predictions suggest that several systems are likely to experience significant net loss of dune habitat over the next century, whilst continued net gain is likely to occur for systems where sediment supply rates remain high. Little net change is predicted in some systems. Considering the 15 dune systems together, it is considered unlikely that net dune habitat loss will exceed net gain over the next 100 years provided that there are no major disruptions to sediment supply and natural coastal processes.