Embryonic and larval development of Babylonia formosae habei (Altena and Gittenberger, 1981) (Gastropoda:Buccinidae) on China''''s coast

The development of embryos and larvae of Babylonia formosae habei living along the southeast coast of China is observed under laboratory conditions. The egg masses are laid by females on hard substrate at night and each capsule contains 100-500 eggs. Each egg is 250-280 mm in diameter. The first two cleavages of the embryo are meridional and equal, and a polar lobe is produced. Larval kidney, which only consists of a single cell, appears during the gastrula stage on each side of the embryo. The right tentacle develops prior to the left one. At 25-27℃, an intracapsulate veliger stage is reached about 4.5 d after deposition. The larvae hatch on the fifth day as swimming veligers with a shell length of 360 -500 mm. The newly hatched larva can ingest suspended algal cells from the water column and remains in the pelagic stage for 8-10 d. The newly settled juveniles are 900-1 200 mm in shell length.     

Embryonic and larval development of Babylonia formosae habei(Altena and Gittenberger, 1981)(Gastropoda: Buccinidae) on China''s coast

The development of embryos and larvae of Babyloniaformosae habei living along the southeast coast of China is observed under laboratory conditions. The egg masses are laid by females on hard substrate at night and each capsule contains 100-500 eggs. Each egg is 250-280 mm in diameter. The fast two cleavages of the embryo are meridional and equal, and a polar lobe is produced. Larval kidney, which only consists of a single cell, appears during the gastrula stage on each side of the embryo. The right tentacle develops prior to the left one. At 25-27 ℃, an intracapsulate veliger stage is reached about 4.5 d after deposition. The larvae hatch on the fifth day as swimming veligers with a shell length of 360 -500 mm. The newly hatched larva can ingest suspended algal cells from the water column and remains in the pelagic stage for 8-10 d. The newly settled juveniles are 900-1 200 mm in shell length.     

Internal migration in a rapidly developing country: the case of Peninsular Malaysia

"This paper discusses the patterns and trends in internal territorial mobility in Peninsular Malaysia from 1957 [to] the 1980s, focussing specially on the period of the 1980s." Data are from Peninsular Malaysian Labour Force Migration Sample Surveys.     

土壤热异常对地表能量平衡影响初探

将来自土壤深部的热通量引入off line的陆面过程模式 (NCAR—LSM ) ,通过长达 2a的数值试验对比分析了它对各层次土壤温度和地表能量平衡的影响。　　在土壤底部引入 5W /m2 的热通量使底层土壤显著升温 ,但升温随着接近表层而迅速衰减。积分 3个月后 ,由地下进入地表的热流量增幅可达 1W/m2 以上 ,并持续增大到 5W /m2 ,地表最大升温约 0 .5K ,同时地表感热、蒸发潜热及长波辐射通量均有 1W /m2 左右的正异常 ;若将土壤热传导系数放大一个量级以加速热量交换 ,则地表升温提高到 1K以上 ,长波辐射增加 3W /m2 以上 ,超过了气溶胶全球平均的辐射效应。结果表明 :一定量值的土壤热异常对地表能量平衡和短期气候变化 (10 -1～ 10 1a)有着不可忽略的影响。同时 ,深入的资料分析、完善的陆面过程模式以及它与大气模式的耦合试验也是亟待进行的相关工作。     

地形变场与现代地壳垂直运动及地震活动关系初探(Ⅰ)——地形变场的计算方法和物理意义

地震与地壳形变有着密切的关系 ,但台站地倾斜资料空间连续性不好 .为此在场分析的基础上 ,利用逐步订正法将地倾斜观测资料内插到 1°× 1°的经纬度网格点 ,引入曲面总曲率的概念计算格点上的Gauss曲率 ,并推广到格点化的有限区域上得到表征曲面形态和变形强度的地表形变场 .结果表明 :该方法可以合理地弥补资料不连续的缺陷 ,并在地表形变场上捕捉到一些关键的地表形变特征 ,如地凸区、地凹区、鞍形场等 .为地震分析和预报中如何拓展和利用大范围时空信息提供了一种有益的思路 .     

Comparative Study of Acid and Alkaline Stimulants with Granite in an Enhanced Geothermal System

The Enhanced Geothermal System (EGS) is an artificial geothermal system that aims to economically extract heat from hot dry rock (HDR) through the creation of an artificial geothermal reservoir. Chemical stimulation is thought to be an effective method to create fracture networks and open existing fractures in hot dry rocks by injecting chemical agents into the reservoir to dissolve the minerals. Granite is a common type of hot dry rock. In this paper, a series of chemical stimulation experiments were implemented using acid and alkaline agents under high temperature and pressure conditions that mimic the environment of formation. Granite rock samples used in the experiments are collected from the potential EGS reservoir in the Matouying area, Hebei, China. Laboratory experimental results show that the corrosion ratio per unit area of rock is 3.2% in static acid chemical experiments and 0.51% in static alkaline chemical experiments. The permeability of the core is increased by 1.62 times in dynamic acid chemical experiments and 2.45 times in dynamic alkaline chemical experiments. A scanning electron microscope analysis of the core illustrates that secondary minerals, such as chlorite, spherical silica, and montmorillonite, were formed, due to acid-rock interaction with plagioclase being precipitated by alkaline-rock interactions. Masking agents in alkaline chemical agents can slightly reduce the degree of plagioclase formation. A chemical simulation model was built using TOUGHREACT, the mineral dissolution and associated ion concentration variation being reproduced by this reactive transport model.     

An index of biotic integrity based on the summer polyhaline zooplankton community of the Chesapeake Bay

A zooplankton index of biotic integrity was developed for the polyhaline waters of the Chesapeake Bay using data from a long-term environmental assessment program in which both zooplankton and water quality were regularly monitored. Summer (July to September) sampling events were classified as either coming from impaired or reference (least-impaired) conditions based on water quality conditions. Seventeen zooplankton community metrics were evaluated under these criteria and nine were chosen for a composite index. These were the Simpson diversity index, and abundance of barnacle larvae, rotifers, cladocerans, copepods, total mesozooplankton, and predators. The composite index of biotic integrity correctly classified about 94% of the impaired samples and about 82% of the reference samples. Average classification efficiency was 88%. This index appears to be an effective measure of eutrophication for the summer polyhaline waters of the Chesapeake Bay ecosystem.     

Middle-late Holocene environment change induced by climate and human based on multi-proxy records from the middle and lower reaches of Yangtze River,eastern China

Our knowledge about the interaction between human activities and the environment in the middle-late Holocene remains incomplete.Core C1 in Lake Chaohu from the middle and lower reaches of Yangtze River (MLYR),eastern China,provides an opportunity to investigate vegetation and climate changes,human activities,and East Asian summer monsoon(EASM) evolution since 5100 cal.yr BP.These variables are assessed based on radiocarbon dating,pollen and charcoal records,and magnetic susceptibility (χ_lf<...     

Biofouling confounds the uptake of trace organic contaminants by semi-permeable membrane devices (SPMDs)

The outer layers of layflat, low density polyethylene plastic tubing (the principal component of semi-permeable membrane devices, SPMDs) were biofouled at a clean site in Hong Kong coastal waters for periods of 1–4 weeks. Following pre-fouling, triolein was added to the SPMDs and, along with control (unfouled) devices, they were exposed to a range of organochlorine pesticides (-HCH, aldrin, p,p^′-DDT) and PAHs (anthracene, fluoranthene and benzo(a)pyrene) under laboratory conditions. Results showed that the uptake of contaminants by SPMDs was severely reduced by as much as 50% under fouling conditions in comparison to unfouled controls. The ultimate utility of SPMDs as passive monitors is thus reduced, although alternative measures, such as the use of permeability reference compounds may compensate, and allow for realistic evaluations of dissolved environmental concentrations in aquatic environments. However, due to the complexities involved in such procedures––especially as they need to be conducted on a case-by-case basis––the utility of SPMDs appears to be limited for estimates of bioavailability unless necessary calibrations are undertaken within each environment that the sampler is used.