Temporal occurrence of ichthyoplankton in relation to hydrographic and biological variables at a fixed station in the St Lawrence Estuary

Spring to autumn temporal distributions of ichthyoplankton and other oceanographic variables were measured at three nearshore stations in the lower St Lawrence Estuary in 1977 and 1978. The seasonal occurrence of various species of fish eggs and larvae was similar from one year to the next. Inshore-offshore gradients in abundance of eggs and larvae of different species appeared to be primarily related to the spawning location of each species. The semidiurnal variability was considerably less than the week-to-week variability in all physical and biological variables measured. The weekly variability is predominantly a function of spatiotemporal interactions, due to the geographic displacement of different water masses and their associated plankton in relation to the neap-spring tidal cycle. The timing and duration of spawning for each common species, inferred from ichthyoplankton distributions, suggest a unique combination of spawning and hatching times, ensuring a succession in the occurrence of larvae through time. Results of the temporal and spatial distributions of the different species of ichthyoplankton are discussed in terms of reduced competitive interactions. The relationship between ichthyoplankton distributions and the plankton production cycle in the St Lawrence Estuary is discussed in comparison with other areas.     

Environmentalism and Natural Aggregate Mining

Sustaining a developed economy and expanding a developing one require the use of large volumes of natural aggregate. Almost all human activity (commercial, recreational, or leisure) is transacted in or on facilities constructed from natural aggregate. In our urban and suburban worlds, we are almost totally dependent on supplies of water collected behind dams and transported through aqueducts made from concrete. Natural aggregate is essential to the facilities that produce energy—hydroelectric dams and coal-fired powerplants. Ironically, the utility created for mankind by the use of natural aggregate is rarely compared favorably with the environmental impacts of mining it. Instead, the empty quarries and pits are seen as large negative environmental consequences. At the root of this disassociation is the philosophy of environmentalism, which flavors our perceptions of the excavation, processing, and distribution of natural aggregate. The two end-member ideas in this philosophy are ecocentrism and anthropocentrism. Ecocentrism takes the position that the natural world is a organism whose arteries are the rivers—their flow must not be altered. The soil is another vital organ and must not be covered with concrete and asphalt. The motto of the ecocentrist is man must live more lightly on the land. The anthropocentrist wants clean water and air and an uncluttered landscape for human use. Mining is allowed and even encouraged, but dust and noise from quarry and pit operations must be minimized. The large volume of truck traffic is viewed as a real menace to human life and should be regulated and isolated. The environmental problems that the producers of natural aggregate (crushed stone and sand and gravel) face today are mostly difficult social and political concerns associated with the large holes dug in the ground and the large volume of heavy truck traffic associated with quarry and pit operations. These concerns have increased in recent years as society's demand for living space has encroached on the sites of production; in other words, the act of production has engendered condemnation. Many other environmental problems that are associated with dust and noise and blasting from quarry and pit operations have been reduced through the efficient use of technology. Recycling concrete in buildings, bridges, and roads and asphaltic pavements will ultimately reduce the demand for virgin natural aggregate. The impact created by the large holes in the ground required for the mining of natural aggregate can be greatly reduced by planning their reclamation before mining begins.     

综合回收利用是山西“阳泉式”硫铁矿开发的必由之路

山西煤系沉积型“阳泉式”硫铁矿床是山西的主要矿床类型。其分布广、储量大 ,且伴生、共生有多种稀有、稀土元素。通过综合回收利用 ,可以减少环境污染、提高资源利用率、扩大资源使用范围、延长矿山服务年限、增强矿山企业的经济效益和社会效益 ,使山西化工矿业持续、稳定、健康发展     

北京地区未来1～3天昼夜气温预报模型

采用T2 1 3数值天气预报产品资料和北京市观象台 ( 5451 1 )实时地面气象观测资料 ,运用神经网络方法 ,建立了北京市观象台 (东郊 )未来 1～ 3天 ( 0～ 72h)夜间、白天、全天平均气温及夜间最低、白天最高气温共 5项气温的预报模式 ,经检验 ,预报的均方根误差 <2℃ ,可满足供热调度节能工作的迫切需要。     

Dimethylsulphide production in the Southern Ocean using a nitrogen-based flow network model and field measurements from ACE-1

Dimethylsulphide (DMS) has been implicated in climate change as a possible negative feedback to global warming, and several Models have been developed that simulate the production of DMS in the marine environment. The focus of this study is to improve the nitrogen based Gabric Model, using field data collected during the Southern Hemisphere First Marine Aerosol Characterisation Experiment (ACE-1) in the Southern Ocean in 1995. Two Model Runs (Series A and B) were carried out with six simulations of varying biotic and abiotic inputs applied over the voyage transect (41-48°S), reflecting Model default values or field values from the experiment. The abiotic inputs were time-step, dissolved dimethylsulphoniopropionate (DMSP) and DMS, and the biotic nitrogen inputs were from phytoplankton, bacteria, zooflagellates, large protozoa, micro and mesozooplankton. The focus of the abiotic assessment was nutrient (nitrate) uptake and dissolved DMSP and DMS output. Model output of the biotic compartments was assessed for congruence with predicted ecological patterns of succession.

Despite a limited data set the study provides a good insight into the utility of the Model, which functioned as a heuristic rather than predictive tool. In simulation 1 (Series A) where the only field value was nitrate, all latitudes from 41-48°S concurred with the ecological succession predicted by the Model authors and the successional pattern predicted by other researchers, with a double phytoplankton peak indicating remineralisation of nitrogen via the microbial loop. In many simulations the Model produced lower values of dissolved DMS than were measured, and production of DMS in the Model appears constrained. However, in simulation 5 (Series A) DMS model outputs were closest to the mean dissolved DMS levels reported on RV Discoverer. In this simulation, field values were used for phytoplankton, nitrate, dissolved DMSP and DMS, with bacterial abundance and micro and mesozooplankton increased over their Gabric default values. Also, the phytoplankton double peak occurred earlier, as did the peaks in bacteria, zooflagellates, and large protozoa. Simulations that deviated more significantly from the predicted successional patterns were characterised by single peaks in phytoplankton growth and delayed bacterial growth. Series C simulations at latitude 43°S, in an attempt to reduce phytoplankton predation by bacteria, increased DMS output reasonably successfully. However, significant recalibration of the Model is recommended in conjunction with field studies to gather vital background biological data - particularly in the areas of nutrient limitation, phytoplankton speciation, and the cellular content of the DMS precursor compound, DMSP.     

节约与创新时代的精益之道

变革一切不合理的生产组织和管理的方式，厉行节约，反对浪费，清除和防治各个环节造成浪费的痼疾，最大优化资源利用；以人为出发点和落脚点，建立富有特色的企业文化，实现民主管理、科学管理、自我管理，调动一切可以调动的因素，开拓创新，科学发展，创造绿色业绩。具有中国特色的精准之道，精益求精，乃希望之路，成功之路。     

决策支持系统模型库管理系统的研究

作者在文中通过对稠油开采决策支持系统模型库管理系统的研究,提出并实现了一种决策支持系统模型管理系统建立的模型。并应用到稠油开发采决策支持系统中,取得了较好的应用结果。     

预测油气田产量的广义Weibull, Wengcycle模型

基于对油田产量预测的Ｗｅｉｂｕｌｌ,Ｗｅｎｇｃｙｃｌｅ模型的研究,提出一个综合模型－广义Ｗｅｉｂｕｌｌ Ｗｅｎｇｃｙｃｌｅ模型。该模型不但可以预测油气田产量随时间的变化,而且也可预测油气田的可采储量、最高年产量及其发生时间。本文探讨了匠性质,曲线特征,提出了一种新的求解参数的方法－等比级数法,并通过实例验证了此方法的可行性及该模型在油气田产量预测中的可靠性。     

1971—2000年中国陆地植被净初级生产力的模拟

利用植被与大气相互作用模式(AVIM),基于气象台站的观测资料模拟了1971—2000年中国陆地生态系统NPP的变化特征.结果表明:1971—2000年我国陆地植被年均NPP变化范围在0~987.67 gC·m^-2·a^-1,全国平均值为349.74 gC·m^-2·a^-1,30 a呈现出递增的变化趋势.对各类植被NPP的模拟显示,最近30 a我国热带雨林、落叶阔叶林以及有地被层的阔叶林的年均NPP减小,而混交林、常绿针叶林、落叶针叶林、有裸土的灌丛、草地以及作物的年均NPP均为增加趋势.由于采用了先进的农业技术,与自然条件下我国作物的年均NPP变化相比,我国实际的粮食单产在上述时期呈显著的增长,表明了人类活动对于我国陆地植被净初级生产力有着深刻的影响.