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31.
Fetuses of women with alloantibodies to RhD (D) are at risk from hemolytic disease of the fetus and newborn, but only if the fetal red cells are D-positive. In such pregnancies, it is beneficial to determine fetal D type, as this will affect the management of the pregnancy. It is possible to predict, with a high level of accuracy, fetal blood group phenotypes from genotyping tests on fetal DNA. The best source is the small quantity of fetal DNA in the blood of pregnant women, as this avoids the requirement for invasive procedures of amniocentesis or chorionic villus sampling (CVS). Many laboratories worldwide now provide noninvasive fetal D genotyping as a routine service for alloimmunized women, and some also test for c, E, C and K. In many countries, anti-D immunoglobulin injections are offered to D-negative pregnant women, to reduce the chances of prenatal immunization, even though up to 40% of these women will have a D-negative fetus. High-throughput, noninvasive fetal D genotyping technologies are being developed so that unnecessary treatment of pregnant women can be avoided. Trials suggest that fetal D typing of all D-negative pregnant women is feasible and should become common practice in the near future. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
32.
Land use change on Indonesian peatlands contributes to global anthropogenic greenhouse gas (GHG) emissions. Accessible predictive tools are required to estimate likely soil carbon (C) losses and carbon dioxide (CO2) emissions from peat soils under this land use change. Research and modelling efforts in tropical peatlands are limited, restricting the availability of data for complex soil model parameterisation and evaluation. The Tropical Peatland Plantation-Carbon Assessment Tool (TROPP-CAT) was developed to provide a user friendly tool to evaluate and predict soil C losses and CO2 emissions from tropical peat soils. The tool requires simple input values to determine the rate of subsidence, of which the oxidising proportion results in CO2 emissions. This paper describes the model structure and equations, and presents a number of evaluation and application runs. TROPP-CAT has been applied for both site specific and national level simulations, on existing oil palm and Acacia plantations, as well as on peat swamp forest sites to predict likely emissions from future land use change. Through an uncertainty and sensitivity analysis, literature reviews and comparison with other methods of estimating soil C losses, the paper identifies opportunities for future model development, bridging between different approaches to predicting CO2 emissions from tropical peatlands under land use change. TROPP-CAT can be accessed online from www.redd-alert.eu in both English and Bahasa Indonesia.  相似文献   
33.
A classification of U.S. estuaries is presented based on estuarine characteristics that have been identified as important for quantifying stressor-response relationships in coastal systems. Estuaries within a class have similar physical and hydrologic characteristics and would be expected to demonstrate similar biological responses to stressor loads from the adjacent watersheds. Nine classes of estuaries were identified by applying cluster analysis to a database for 138 U.S. estuarine drainage areas. The database included physical measures of estuarine areas, depth and volume, as well as hydrologic parameters (i.e., tide height, tidal prism volume, freshwater inflow rates, salinity, and temperature). The ability of an estuary to dilute or flush pollutants can be estimated using physical and hydrologic properties such as volume, bathymetry, freshwater inflow and tidal exchange rates which influence residence time and affect pollutant loading rates. Thus, physical and hydrologic characteristics can be used to estimate the susceptibility of estuaries to pollutant effects. This classification of estuaries can be used by natural resource managers to describe and inventory coastal systems, understand stressor impacts, predict which systems are most sensitive to stressors, and manage and protect coastal resources.  相似文献   
34.
This article presents an overview of the sustainability initiative at the University of Minnesota, Morris, key components of which include a realistic goal of energy self-sufficiency by 2010, a new environmental studies curriculum, and various research and outreach projects. Many non-obvious institutional assets – such as lobbying networks in the state legislature, and geographic/demographic features that are more commonly thought of as liabilities – turned out to play critical roles in setting the initiative in motion. The initial physical assets have been leveraged into complementary opportunities for research, teaching, and institutional development in this direction.  相似文献   
35.
The application of potassium ferrate for sewage treatment   总被引:12,自引:0,他引:12  
The comparative performance of potassium ferrate(VI), ferric sulphate and aluminium sulphate for the removal of turbidity, chemical oxygen demand (COD), colour (as Vis400-abs) and bacteria in sewage treatment was evaluated. For coagulation and disinfection of sewage, potassium ferrate(VI) can remove more organic contaminants, COD and bacteria in comparison with the other two coagulants for the same doses used. Also, potassium ferrate(VI) produces less sludge volume and removes more contaminants, which should make subsequent sludge treatment easier.  相似文献   
36.
Cypress domes are non-transient, disconnected, depressional wetland areas scattered about the southern United States. Baldcypress (Taxodium distichum (L.) Rich.), swamp tupelo (Nyssa sylvatica var. biflora) and other trees species typically occupy these sites. Even though these areas are relatively fixed on the landscape, given land use changes over the last 60–70 years, the spatial character of the resource may have undergone some change as well. A small case study of one Georgia county suggests that there was net decrease in cypress dome land area from 1940 to 2007. The case study also suggests that there was a significant change in the land class(es) adjacent to or containing cypress domes. In addition, the physical shape of cypress domes seems to have changed, perhaps due to mechanical treatment of the land during commercial forestry operations. While the shape of cypress domes that were adjacent to mature forests in 1940 was not significantly different than the shape of the same cypress domes that were adjacent to mature forests in 2007, the shape of cypress domes adjacent to agricultural land and pasture/forest land uses in 1940 was significantly different in shape than their 2007 counterparts. Thus, the value of this study is in suggesting that the physical shape of cypress domes that were once adjacent to agricultural or pasture/forest lands seems to have changed, perhaps due to mechanical treatment of the land during the transition from agricultural practices to commercial forestry operations. The study also highlights the need for assessing the hydrologic changes in wetland function due to changes in cypress dome shape, and due to mechanical operations used along the edges of cypress domes to effectively adjust their shape. Research along these lines can lead to a better understanding of the spatial character of the cypress resource in areas that were once used for agricultural or pasture/forest purposes and may lead to more effective management strategies for protecting its role in society.  相似文献   
37.
Insect-growth regulators (IGRs) have been receiving foremost attention as potential means of selective insect control. Benzoyl phenyl urea (BPU) is a well-known IGR having chitin synthesis inhibitor activity. Mimics of BPU have been synthesized by suitable derivatization of a naturally occurring monoterpenoid, thymol (2-isopropyl-5-methyl phenol) to form a = series of substituted benzoyl thymyl thioureas (BTTUs) [IVa-f] and benzoyl thymyl ureas (BTUs) [Va-f]. The synthesized compounds have been characterized by (1)H and (13)C NMR, LC-MS and elemental analysis. These derivatives have been screened for their effect on total haemocyte count of Dysdercus koenigii. It has been observed that the introduction of substituted benzoyl thiourea and urea linkage into a thymol ring via an amino group results in higher activity than the parent compound thymol and a comparable pattern of results with the standard insect-growth regulators, Penfluron. Urea [Va-f] compounds exhibited greater effect on Total Haemocyte Count (THC) than thiourea [IVa-f]. Fluoro substitution enhanced the effect on THC more than chloro substituted compounds, while ortho-substitution resulted in a better effect than para-substitution. The results described in this paper are promising and provide new array of synthetic chemicals that may be utilized as insect growth regulators.  相似文献   
38.
Measurement sensitivity and bias quality control metrics are commonly reported for water-quality parameters measured in the laboratory. Less commonly recognized is that they should also be reported for field-measured parameters. Periodic evaluation helps document data quality and can help serve as early warning if there are problems with methods or techniques that could negatively affect ability to interpret threshold values and trends over time. This study focuses on traditional assessment of bias and introduces a new method for estimating measurement sensitivity of water-quality parameters measured monthly in the field. Alternative measurement sensitivity is a new data quality indicator used to demonstrate how quantifying sensitivity at the measurement level can improve understanding the uncertainty affecting each reported data value. That, in turn, can help interpret the meaning of results from many separate data points measured in the field. In this 30-month study, pH and specific conductance consistently met, and dissolved oxygen did not always meet NPS and USGS quality control standards for bias. Evaluation of dissolved oxygen bias and sensitivity during the study provided impetus to improve calibration techniques that resulted in data that later met quality goals.  相似文献   
39.
Kanchenjunga Conservation Area Project (KCAP) in Nepal is among the first protected areas in the world to institute a completely decentralized system of conservation and development. Proponents of decentralized conservation claim that it increases management efficiency, enhances the responsiveness to local needs, and promotes greater equity among local residents. This study assessed local equity by evaluating the levels of dependencies on natural resources among households and the factors affecting that dependency. Data were collected via detailed surveys among 205 randomly selected households within the KCAP. Natural resource dependency was evaluated by comparing the ratio of total household income to income derived from access to natural resources. Economic, social, and access-related variables were employed to determine potential significant predictors of dependency. Overall, households were heavily dependent on natural resources for their income, especially households at higher elevations and those with more adult members. The households that received remittances were most able to supplement their income and, therefore, drastically reduced their reliance on the access to natural resources. Socio-economic variables, such as land holdings, education, caste, and ethnicity, failed to predict dependency. Household participation in KCAP-sponsored training programs also failed to affect household dependency; however, fewer than 20% of the households had any form of direct contact with KCAP personnel within the past year. The success of the KCAP as a decentralized conservation program is contingent on project capacity-building via social mobilization, training programs, and participatory inclusion in decision making to help alleviate the dependency on natural resources.  相似文献   
40.
The infiltration and biodegradation of medium molecular weight hydrocarbons were studied in field and lysimeter experiments. An initial loading rate of 4 kg m(-2) of a gas-oil cut (nC12-nC21) was applied and the weathering of hydrocarbons was monitored by gravimetry and capillary gas-chromatography. The composition and vertical distribution of biogenic hydrocarbons were studied in control plots. After 3.5 years, 94% of the fossil hydrocarbons were removed from the field and 83% from the lysimeter. Microbial degradation was active in the 30 cm upper layer of the soil. The undegraded residue was composed of cyclic alkanes and aromatics. Hydrocarbons were shown to penetrate down to 60 cm in the field and 80 cm in the lysimeter. A preferential infiltration of light hydrocarbons was noted in the lysimeter, and a selective adsorption of the heaviest compounds on the organo-mineral matrix was demonstrated in the superficial layer of the soil. The potential for leaching of unmodified hydrocarbons towards the groundwater was slight, whereas the input of total organic carbon resulting from microbial activity could account for more than 1% of the initial carbon load.  相似文献   
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