用TRXRF分析法测试马来西亚微咸水中双壳类软体动物Geloina ceylonica(Lamarck)中的重金属

马来西亚有近2.4%的陆地面积(相当于650,000公顷)是红树林沼泽区。其中,110,000公顷在马来西亚半岛,174,000公顷在沙捞越,366,000公顷在马来西亚的沙巴。当前对于马来西亚红树林沼泽区的生态研究还寥寥无几(Sase Kumar,1970;Ong等人,1979)。对植物区系和动物区系的研究显然也是如此(Berry,1968,1972和1974;Lim,     

A line survey of Orion KL from 325 to 360 GHz

We present a high-sensitivity spectral line survey of the high-mass star-forming region Orion KL in the 325-360 GHz frequency band. The survey was conducted at the Caltech Submillimeter Observatory on Mauna Kea, Hawaii. The sensitivity achieved is typically 0.1-0.5 K and is limited mostly by the sideband separation method utilized. We find 717 resolvable features consisting of 1004 lines, among which 60 are unidentified. The identified lines are due to 34 species and various isotopomers. Most of the unidentified lines are weak, and many of them most likely due to isotopomers or vibrationally or torsionally excited states of known species with unknown line frequencies, but a few reach the 2-5 K level. No new species have been identified, but we were able to strengthen evidence for the identification of ethanol in Orion and found the first nitrogen sulfide line in this source. The molecule dominating the integrated line emission is S02, which emits twice the intensity of CO, followed by SO, which is only slightly stronger than CO. In contrast, the largest number of lines is emitted from heavy organic rotors like HCOOCH3, CH3CH2CN, and CH3OCH3, but their contribution to the total flux is unimportant. CH3OH is also very prominent, both in the number of lines and in integrated flux. An interesting detail of this survey is the first detection of vibrationally excited HCN in the v2 = 2 state, 2000 K above ground. Clearly this is a glimpse into the very inner part of the Orion hot core.     

A multi-level perspective on small-area health and mortality: a case study of England and Wales

"This paper considers morbidity and mortality variations at the small-area level in England and Wales and their relation to socio-economic factors. Separate affluence and deprivation effects on illness and mortality are identified from a single-level analysis, both exceeding the influence of social class, urbanity or ethnicity. A multi-level perspective is then adopted to explore ecological associations operating both at micro-area and higher level spatial scales. Contextual effects (higher level variability in the impacts of ward level variables) are identified in the effects of small area deprivation on mortality and illness, as well as cross-level interactions; thus the impact of small area social structure on health is partly defined by the wider regional and district setting."     

The selection of internal migration models for European regions

"A full multiregional projection model requires migration data that are simultaneously classified by age and gender and region of origin and region of destination. Except for a very small number of regions, these data requirements are so high that aggregation of the data (which is equivalent to simplification of the model) is called for. This paper investigates the extent to which the full internal migration matrix can be simplified without seriously affecting the performance of the resulting multiregional model. Using IPF (iterative proportional fitting) methods, a log-linear analysis of alternative model specifications is made, using data for Italy, the Netherlands and the UK....A reasonable balance between goodness-of-fit and parsimony is found for the model in which time interacts with the main effects only (i.e. with age/sex, with origin and with destination)."     

Geology Along the Line from Yecheng to Shiquanhe and Tectonic Evolution of the Region Involved

The geotraverse from Yecheng to Shiquanhe, on the western Qinghai-Tibet Plateau, totalling 1056 km in length, passes the western Kunlun Mountains and the eastern end of the Karakorum Mountains. The Chinese and French scientists made a joint investigation along the line from July to August, 1989. Based on the outcropped ophiolites, palaeontology, sedimentary facies, magmatism, tectonic deformation and metamorphism, the region involved may be divided from north to south into five terranes and four ophiolitic suture zones. The ages of these terranes have a tendency to become increasingly younger from north to south.     

Immigration--mismatches in labour,housing and space: the effects of immigration of several nationalities with regard to the Netherlands

"In the Netherlands, the sharp recent increase of the number of refugee immigrants (asylum seekers) runs parallel to increased numbers of immigrants of other types. Therefore, at least five types of immigrants should still be distinguished (labour migrants, migrants from former colonies, from EU countries, from other rich countries, and asylum seekers). Their spatial orientation in the Netherlands (urban, suburban, rural), by choice or by constraint, is the main focus of this study. The outcomes of the immigration processes have been confronted with general and spatial characteristics of the labour market and housing market. Matches and mismatches are discussed."     

Public housing as a barrier to long-distance migration

The relationship between migration and housing tenure in Britain is explored, with particular reference to those living in subsidized housing provided by local councils. "In this study, data have been extracted from the 1991 Sample of Anonymised Records to assess the impacts of tenure on long-distance migration compared with short-distance migration. Logit models are used to control for the effects of a wide range of socio-economic variables, allowing the independent impact of tenure to be identified. It is shown that long-distance migrants are less likely to move into council housing than other tenures, but it is argued that this does not support the assumption that the sale of council housing will necessarily increase labour mobility."     

大洋渔业面临着极限

当今世界海洋渔业正处于危机之中。渔民面临的根本问题是自身的捕鱼能力和政府反作用力的政策,即使在渡过报酬递减点之后,这些政策也使越来越多的渔民和渔船进入商贸领域。在经过10多年购置大船,加大先进捕捞技术投资之后,渔民海洋捕捞几乎达到了极限。世界15个主要海洋渔场,除2个渔场外,所有渔     

Effects of dietary exposure to the pyrethroid pesticide esfenvalerate on medaka (Oryzias latipes)

The pyrethroid insecticide esfenvalerate is widely used on orchard crops throughout California. In the aquatic environment, this compound is likely to accumulate in sediments, food particles and benthic organisms due to its lipophilicity and environmental persistence. This pilot project tested the hypothesis that esfenvalerate is toxic to medaka (Oryzias latipes) when taken up with the diet. For 7 days fish were fed diets, which contained esfenvalerate in three different concentrations (4, 21, 148 mg/kg, measured). Endpoints measured were mortality, fecundity, fertilization and hatching success of embryos, viability of larvae and cellular stress protein (hsp60, hsp70, hsp90) levels. The toxicity of aqueous exposure of medaka to esfenvalerate was also determined. Whereas the 96-h LC50 in the aqueous exposure was <9.4 microg/l, the dietary exposure did not cause mortality. Possible effects of dietary esfenvalerate were seen on fertilization and hatching success and the number of non-viable larvae. Expression of hsp60 and hsp90 showed a dose-dependent response pattern.     

Response of Coastal Groundwater Table to Offshore Storms

Large groundwater table fluctuations were observed in a coastal aquifer during an offshore storm. The storm induced significant changes of the mean shoreline elevation, characterized by a pulse-like oscillation. This pulse propagated in the aquifer, resulting in the water table fluctuations. A general analytical solution is derived to quantify this new mechanism of water table fluctuation. The solution is applied to field observations and is found to be able to predict reasonably well the observed storm-induced water table fluctuations. Based on the analytical solution, the damping characteristics and phase shift of the oscillation as it propagates inland are examined.