A baseline study of physico-chemical parameters and trace metals in waters of Ennore Creek, Chennai, India   总被引：2，自引：0，他引：2  

Jayaprakash M  Srinivasalu S  Jonathan MP  Mohan VR 《Marine pollution bulletin》2005,50(5):583-589

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南Dakota黑生区与一个早元古宙变质地体热演...     

Terry  MP 李维海 《世界地质》1992,11(1):176-180

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赞斯卡尔,库卢,拉胡尔和克什米尔高喜马拉雅含石榴石...     

Seale  MP 王艺芬 《国外地质(北京)》1990,(4):38-48

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高钾,钙碱性Ⅰ型花岗岩类的成因     

Robe.  MP 杨秋剑 《地质地球化学》1995,(6):66-70

许多Ⅰ型花岗岩类岩浆是由较老的变火成岩经部分熔融而形成的，这类溶体的组成大致是钙碱性和准铝质的。这些熔体是花岗质至英云闪长质熔体，是在其下地壳源区内的极端热条件下形成的。  相似文献   

Ethnic and gender divisions in the work force of Russia     

Sacks MP 《Post-Soviet geography》1995,36(1):1-12

Like the former Soviet Union, Russia is home to many ethnic groups. The Russian Federal Treaty of March 1992 was signed by 18 ethnically-based republics and 17 non-Russian ethnic districts. Ethnic groups within Russia vary considerably in levels of socioeconomic achievement, with groups having had unequal access to political resources and differing in their ability to take advantage of economic opportunities. The author analyzed newly available occupational data from the 1989 census in his study of ethnic and gender differences in the work force of Russia. Measurements are presented showing differences between the occupations of Russians and the next largest 11 ethnic groups, producing a clear hierarchy of groups. The extent of occupational gender differences within each ethnic group is measured and contrasted with the level of differences between ethnic groups. These data are important for showing potential sources of group conflict and for providing a baseline to measure changing forms of inequality which have been promoted by post-Soviet developments. Preliminary findings point to the existence of highly significant differences between Russia's ethnic groups, with the level of the differences closely paralleling measures of socioeconomic achievement. To determine more precisely the significance of group differences in employment, detailed occupational categories must be examined more closely. Currently available data, however, do not permit more rigorous measurements of discrimination. It is nonetheless clear that ethnicity in contemporary Russia is strongly related to occupational differences. The aggregate segregation of men from women was found to be very stable despite the substantial socioeconomic and cultural differences between ethnic groups. As a group, Jews were found to have extremely high levels of educational and occupational achievement and a comparatively far older age structure.  相似文献   

Foreign minorities from developing countries in Madrid     

Rodriguez V  Aguilera MJ  Gonzalez-yanci MP 《GeoJournal》1993,30(3):293-300

Spain, which has always been a land of emigrants, is currently a centre of attraction for immigrants, as are other countries in Mediterranean Europe. The proportion is not as high as in other countries with a longer tradition of immigration. In this survey we selected the six nationalities which provide the highest numbers of immigrants from the developing world, and which have the greatest racial or cultural contrast to the native population. We analyse their structural features, whether or not immigrants from the same country are collect in the Madrid Metropolitan Area, the recent mobility of the immigrant population, and the evolution of immigration since the Administration carried out a regularization process, as well as Spaniards' opinion of foreign immigrants.  相似文献   

Vulnerability of a public supply well in a karstic aquifer to contamination     

Katz BG  McBride WS  Hunt AG  Crandall CA  Metz PA  Eberts SM  Berndt MP 《Ground water》2009,47(3):438-452

To assess the vulnerability of ground water to contamination in the karstic Upper Floridan aquifer (UFA), age-dating tracers and selected anthropogenic and naturally occurring compounds were analyzed in multiple water samples from a public supply well (PSW) near Tampa, Florida. Samples also were collected from 28 monitoring wells in the UFA and the overlying surficial aquifer system (SAS) and intermediate confining unit located within the contributing recharge area to the PSW. Age tracer and geochemical data from the earlier stage of the study (2003 through 2005) were combined with new data (2006) on concentrations of sulfur hexafluoride (SF₆), tritium (³H), and helium-3, which were consistent with binary mixtures of water for the PSW dominated by young water (less than 7 years). Water samples from the SAS also indicated mostly young water (less than 7 years); however, most water samples from monitoring wells in the UFA had lower SF₆ and ³H concentrations than the PSW and SAS, indicating mixtures containing high proportions of older water (more than 60 years). Vulnerability of the PSW to contamination was indicated by predominantly young water and elevated nitrate-N and volatile organic compound concentrations that were similar to those in the SAS. Elevated arsenic (As) concentrations (3 to 19 μg/L) and higher As(V)/As(III) ratios in the PSW than in water from UFA monitoring wells indicate that oxic water from the SAS likely mobilizes As from pyrite in the UFA matrix. Young water found in the PSW also was present in UFA monitoring wells that tap a highly transmissive zone (43- to 53-m depth) in the UFA.  相似文献   

Importance of unsaturated zone flow for simulating recharge in a humid climate     

Hunt RJ  Prudic DE  Walker JF  Anderson MP 《Ground water》2008,46(4):551-560

Transient recharge to the water table is often not well understood or quantified. Two approaches for simulating transient recharge in a ground water flow model were investigated using the Trout Lake watershed in north-central Wisconsin: (1) a traditional approach of adding recharge directly to the water table and (2) routing the same volume of water through an unsaturated zone column to the water table. Areas with thin (less than 1 m) unsaturated zones showed little difference in timing of recharge between the two approaches; when water was routed through the unsaturated zone, however, less recharge was delivered to the water table and more discharge occurred to the surface because recharge direction and magnitude changed when the water table rose to the land surface. Areas with a thick (15 to 26 m) unsaturated zone were characterized by multimonth lags between infiltration and recharge, and, in some cases, wetting fronts from precipitation events during the fall overtook and mixed with infiltration from the previous spring snowmelt. Thus, in thicker unsaturated zones, the volume of water infiltrated was properly simulated using the traditional approach, but the timing was different from simulations that included unsaturated zone flow. Routing of rejected recharge and ground water discharge at land surface to surface water features also provided a better simulation of the observed flow regime in a stream at the basin outlet. These results demonstrate that consideration of flow through the unsaturated zone may be important when simulating transient ground water flow in humid climates with shallow water tables.  相似文献   

Field verification of stable perched groundwater in layered bedrock uplands     

Carter JT  Gotkowitz MB  Anderson MP 《Ground water》2011,49(3):383-392

Data substantiating perched conditions in layered bedrock uplands are rare and have not been widely reported. Field observations in layered sedimentary bedrock in southwestern Wisconsin, USA, provide evidence of a stable, laterally extensive perched aquifer. Data from a densely instrumented field site show a perched aquifer in shallow dolomite, underlain by a shale-and-dolomite aquitard approximately 25 m thick, which is in turn underlain by sandstone containing a 30-m-thick unsaturated zone above a regional aquifer. Heads in water supply wells indicate that perched conditions extend at least several kilometers into hillsides, which is consistent with published modeling studies. Observations of unsaturated conditions in the sandstone over a 4-year period, historical development of the perched aquifer, and perennial flow from upland springs emanating from the shallow dolomite suggest that perched groundwater is a stable hydrogeologic feature under current climate conditions. Water-table hydrographs exhibit apparent differences in the amount and timing of recharge to the perched and regional flow systems; steep hydraulic gradients and tritium and chloride concentrations suggest there is limited hydraulic connection between the two. Recognition and characterization of perched flow systems have practical importance because their groundwater flow and transport pathways may differ significantly from those in underlying flow systems. Construction of multi-aquifer wells and groundwater withdrawal in perched systems can further alter such pathways.  相似文献   

Trace element concentrations in nesting flatback turtles (Natator depressus) from Curtis Island, Queensland, Australia     

Ikonomopoulou MP  Olszowy H  Limpus C  Francis R  Whittier J 《Marine environmental research》2011,71(1):10-16

The blood and eggs of the flatback turtle (Natator depressus) sampled when nesting at Curtis Island, Queensland, Australia. In the blood, zinc was present at the highest concentration of 151.15 ± 1.45 μg/L followed by copper (7.74 ± 0.09 μg/L). Lead was found only in some individuals. The measured trace elements in the blood were maternally transferred into the eggs. Other metals and metalloids detected in eggs were chromium, manganese, arsenic and selenium. Eggs showed a more complex trace element profile than blood, suggesting that they provided more representative tissues for determining maternal levels of trace element accumulation in N. depressus. Intra-clutch variation was over 15% for most of the studied trace elements suggesting one egg is not in sufficient to determine trace element accumulation within a clutch. Copper was the only element which was positively correlated with breeding age. Furthermore, no detectable levels of tin compound derivates were measured in N. depressus.  相似文献