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Dubey KN 《Population geography : a journal of the Association of Population Geographers of India》1990,12(1-2):45-58
"The main objective of the present paper is to discern the changing pattern of regional disparities in demographic development in India. The analysis pertains to the 1971-81 decade using district level data. Indicators have been selected from the demographic components of urbanisation, literacy and occupational dynamism." 相似文献
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Distribution and accumulation of organotin species in seawater, sediments and organisms collected from a Taiwan mariculture area 总被引:4,自引:0,他引:4
The present study was undertaken to evaluate the distribution and accumulation of tributyltin (TBT) and triphenyltin (TPhT) in seawater, sediments and selected organisms from a cage mariculture area in southern Taiwan, Hsiao Liouchiou Island. Our results show that ΣOTs were found in concentrations as high as 196 ng/L in seawater collected from the sites in Pai-Sa harbor, and up 1040 ng/g dry wt. in sediments dredged from sites within Da-Fu harbor. Also, ΣOTs concentrations of 859 ng/g dry wt. were observed in the liver of cobia (Rachycentron canadum) from mariculture cages. As most published studies have focused on the acute toxicity and bioaccumulation of organotins in mussels, the effects of organotins on cobia and other marine fauna are still poorly understood. This study highlights the significance of ΣBTs accumulation in cobia, as well as in the sediments and seawater surrounding their culture facilities. 相似文献
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Screening of surfactants for harmful algal blooms mitigation 总被引:6,自引:0,他引:6
Screening experiments were conducted in order to find promising synthetic surfactants for harmful algal blooms (HABs) mitigation. The chemically synthesized surfactant cocamidopropyl betaine (CAPB) showed characteristics of relatively high inhibition efficiency, high biodegradability and low cost. The motility inhibition ratios of 10 mg/L CAPB on Cochlodinium polykrikoides and Alexandrium tamarense were about 60% after 5 min. The biodegradation test indicated that the half-life of CAPB in seawater was shorter than one day and 90% was biodegraded after five days under the initial concentration of 100 mg/L at 25 degrees C. Further cell lysis experiments revealed the selective lysis effect of CAPB on different HAB organisms. More than 90% of C. polykrikoides lysed at the concentration of 10 mg/L CAPB after 24 h and at 15 mg/L CAPB after 4 h, whereas the lysis effect of CAPB on A. tamarense was slight, no more than 10% after 2 h interaction with 50 mg/L CAPB. This research provided preliminary data for CAPB as a candidate in harmful algal blooms mitigation and pointed out unresolved problems for its practical application in the meantime. 相似文献
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In the present work, we built a mathematical model of polychlorinated biphenyl (PCB) bioaccumulation in Perna viridis, namely, a one-compartment model with a time dependent incorporation rate R (μg g−1 lipid per ppb water per day), with positive substrate cooperativity as the underlying physical mechanism. The temporal change of the PCB concentration Q (μg g−1 lipid) in the soft tissues of the mussel depends on the competition of the input rate RW and the output rate kQ, where W is the concentration of PCB in water (ppb water) and k is the elimination rate (per day). From our experimental data, k=0.181±0.017 d−1. The critical concentration in water Wc for positive substrate cooperativity was found to be 2.4 ppb. Below Wc, R is a constant. For a water concentration of 0.5 ppb Aroclor 1254, R=24.0±2.4 μg g−1 lipid ppb−1 d−1. Above Wc, positive substrate cooperativity comes into effect and R becomes a function of time and dependent on the concentration Q in a form R=γQ/(Q+δ). This is the case for a water concentration of 5 ppb Aroclor 1254, where γ=15.1 μg g−1 lipid ppb−1 d1 and δ≈200 μg g−1 lipid. From this model, the uptake is exponentially increasing when the PCB concentration in the mussel is small compared to 200 μg g−1 lipid, and hyperbolically increasing when the concentration is large compared to 200 μg g−1 lipid, which are consistent with the experimental data. The model is useful for understanding the true processes taking place during the bioaccumulation and for risk assessment with higher confidence. Future experimental data which challenge the present model are anticipated and in fact desirable for improvement and perfection of the model. 相似文献
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Singh LR Dubey KN 《Population geography : a journal of the Association of Population Geographers of India》1985,7(1-2):27-39
"Patterns of and trends in demographic development in the Indian state of Uttar Pradesh have been analysed in this paper. Indices of urbanisation, literacy and occupational structure were used for this purpose. Their aggregate index represented the level of demographic development." The data are for 242 subdivisions of Uttar Pradesh for the census years 1971 and 1981. Particular attention is given to regional differentials in demographic indicators. The relationships among economic development and the measurements of literacy, urbanization, and occupational status are explored 相似文献
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The new politics of family planning in the 1990s has involved the articulation of a comprehensive concept of sexual and reproductive health (SRH). Following the ratification of the SRH concept and goals at recent international conferences, one major issue is how governments translate the broad statements into operational policies and programs. The authors consider the ways in which the process is occurring in Indonesia, defining SRH, and reviewing the levels of its attainment in 8 of its components in Indonesia. The policy process in Indonesia is explored with regard to pre-existing reassessments, setting important priorities and moralistic and pragmatic policy orientations. The following SRH components are discussed: family planning, infertility, maternal and child health, HIV/AIDS, sexually transmitted diseases, adolescents' needs, sexual health, and gender issues. In terms of SRH, Indonesia has achieved considerable success in addressing family planning and infant and child mortality, limited success in addressing maternal mortality and HIV/AIDS, and very little progress in addressing STDs, adolescent needs, and positive sexuality. There are few data on gender issues. 相似文献