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131.
Chang-Hee Christine Bae 《Journal of Environmental Planning and Management》1997,40(2):235-260
This paper examines how air pollution control policies will affect the welfare of the different races in Southern California. The paper adopts the concept of the Net Welfare Impact (NWI) function to measure how air quality improvements affect the welfare (monetary and non-monetary) of individual households. The core finding is that many of the benefits of air quality improvement are enjoyed by minorities, especially Latinos (and African-Americans and Asians to a lesser extent), whose household incomes tend to be lower and family size larger than the regional average, and who are more likely to live in the neighbourhoods that are currently polluted. Thus, because minorities have suffered more from dirty air, they are the major beneficiaries from implementation of clean air policies. This is the result of the Federal clean air mandate that dictates uniform standards for all metropolitan areas. 相似文献
132.
Christine A. Matthews 《Journal of the American Water Resources Association》1991,27(5):841-847
ABSTRACT: Southern California, now in its fifth consecutive year of drought, has always relied heavily on imported water from the Owens Valley, the State Water Project, and the Colorado River. For various reasons, these sources are now decreasing and water suppliers are being forced to look for new sources. One possible alternative is to store water obtained during peak supply periods for use during dry periods in ground water storage basins. The Santa Ana River Basin in Orange County has already been developed, and is being used to provide water to 25 cities in Orange County. The San Juan Basin, also in Orange County, is being studied as a possible future storage basin. This paper examines some of the positive and negative aspects of developing and using ground water storage basins in Southern California. 相似文献
133.
134.
Blasing T. J. Broniak Christine Marland Gregg 《Mitigation and Adaptation Strategies for Global Change》2005,10(4):659-674
Time series of fossil fuel carbon emissions from 1960–2000 for each of the U.S. states and the District of Columbia are presented
and discussed. Comparison of the nationally summarized results with other national datasets shows generally good agreement,
usually within 2%, and gives insight into the quality of all the data series. Our extension of the state-by-state emissions
estimates back to 1960 reveals patterns of change that are coherent across states and can be related to historic events such
as energy crises and federal legislation. Most notable is the changing pattern of coal usage, as coal-producing states produce
increasingly more energy (mostly for electricity) for other states so that per capita CO2 emissions diverge for states that import as opposed to those that export electricity. The decline in carbon emissions from
petroleum products following the 1970s is also evident. Per capita emissions range over an order of magnitude for the different
states. The data suggest that differences in per capita emissions arise from differences in many technological, physical,
resource, social, and economic factors. The data presented here and the few correlations briefly noted pose a challenge for
trying to use per capita emissions as a measure of equity or to provide mitigation targets. 相似文献
135.
Prenatal diagnosis performed by fetal karyotype and ultrasound scan is now a routine part of antenatal care in many countries. How many fetal anomalies are actually detected by these procedures? We have used our registry of congenital malformations to answer this question. In our region, prenatal diagnosis was performed in 23.1 per cent of fetuses with a chromosomal aberration and in 20.1 per cent of fetuses with non-chromosomal anomalies. Only 6.9 per cent of the pregnancies with fetuses with non-chromosomal anomalies were terminated. The sensitivity of prenatal diagnosis by ultrasonographic examination was much lower for isolated malformations (fetuses with only one anomaly) than for multiple malformed children, 15.3 and 48.3 per cent respectively, chromosomal anomalies excluded. 相似文献
136.
Prenatal diagnosis performed by fetal ultrasound scan is now a routine part of antenatal care in many countries. That an increasing number of fetal anomalies may be detected on prenatal ultrasound is beyond doubt. What is possible is not, however, always practical, especially when congenital heart diseases (CHDs) are concerned and when whole antenatal populations are screened rather than high-risk groups. Thanks to our registry of congenital anomalies, a retrospective study was undertaken to evaluate the prenatal detection of CHDs by ultrasound scan in 131 760 consecutive pregnancies of known outcome from 1979 to 1988. Only 84 out of 912 malformed fetuses with CHDs without chromosomal anomalies were detected (9.2 per cent). The sensitivity of detection varied from around 38 per cent for malformations such as hypoplastic left heart and single ventricle to around 5 per cent for ventricular and atrial septal defects. The effectiveness of the detection of some forms of major congenital heart disease has increased dramatically since 1987 by including routine examination of the four-chamber view and of the inflow and outflow tracts of the fetal heart. Our results stress the need to obtain a definite clear four-chamber view, to perform scans at ⩾ 18 weeks of gestation, and to train sonographers in order to improve the prenatal detection of CHDs. 相似文献
137.
Prenatal diagnosis performed by ultrasound scan is now a routine part of prenatal care in many countries. How many fetal anomalies are actually detected by these procedures? We have used our registry of congenital malformations to answer this question. In a previous study (Prenat. Diagn., 12 , 263–270, 1992), considering the period 1979–1988, we have shown that prenatal diagnosis was performed in 23.1 per cent of fetuses with a chromosomal aberration and in 20.1 per cent of fetuses with non-chromosomal anomalies. In 1991 and 1992, the percentatge of termination for Down syndrome was 44.4 and 41.9 per cent, respectively. From 1989 to 1992, the detection rate and the specificity of prenatal diagnosis by ultrasonographic examination were improved. The detection rate for isolated malformations (fetuses with only one anomaly) and for multiple malformed children was 26.2 and 66.0 per cent, respectively. The detection rate of congenital anomalies by ultrasonography was variable for the different categories of malformation. A high detection rate was observed for anencephaly (100 per cent) and urinary tract malformation. A low detection rate was seen for cleft lip (17.5 per cent) and limb reduction defects (18.2 per cent). 相似文献
138.
Christine H. Petersen 《Marine Biology》2007,150(6):1289-1300
Discrete estuary subpopulations of the mud crab Hemigrapsus oregonensis (Dana, 1851) are connected via larval dispersal. Sequence variation at the mtDNA COI locus was examined in eight populations
sampled in 2001–2002 from central California through northern Oregon in the northeast Pacific (36.6–45.8°N) to infer patterns
of dispersal and historical connectivity in the region. Strong evidence for persistence since the mid-Pleistocene, with no
range truncation resulting from southward shifting temperature isoclines, was provided by a phylogeographic pattern of haplotypes
of an older clade distributed throughout the sampled range. A recently derived clade became widespread only north of Cape
Blanco after the last glacial maximum. Its clear pattern of restriction to the northern area, in the absence of similarly
restricted southern clades, suggests that contemporary dispersal around Cape Blanco is rare (population F
ST = 0.192). Low pairwise differentiation within Oregon and within central California, as well as contrasts between northern
and southern groups in the shape of the pairwise mismatch distribution, nucleotide diversity, and Tajima’s D suggest that these regions reflect different demographic histories. Potential mechanisms explaining this latitudinal break
include contemporary coastal circulation patterns, selection, and ancient patterns of larval dispersal in the California Current. 相似文献
139.
Laboratory 45Ca-incorporation rates in hermatypic coral skeletons have previously been used successfully as an index of physiological function. This laboratory method would become more meanigful if it also provided an absolute measure of coral growth rates. In two coral species, Porites compressa and Pocillopora damicornis, 45Ca incorporation rates were obtained from short (0.5 h) laboratory incubations using apical (determined as fast growing) portions of freshly collected coral branches. 45Ca exchange across the coenosarc was not significant and not corrected for, whereas diurnal fluctuation in 45Ca in Pocillopora damicornis was significant and a necessary correction. A calculated surface area is used to express calcification rate. Typical growth rates calculated from the 45Ca-incorporation rates were 20 and 6 mm/year for Porites compressa and Pocillopora damicornis, respectively. These rates are considerably higher than those previously obtained in the laboratory, and compare favorably with field growth rates — 24 and 14 mm/year, respectively. 相似文献
140.
Organochlorine pesticides were widely used in the past in Sumas Prairie, British Columbia, Canada. In the 1990s, the hatching success of amphibians from agricultural sites was significantly depressed in the Sumas Prairie compared to reference sites. Therefore, in this study, organochlorine pesticides and polychlorinated biphenyls (PCBs) were measured in eggs of red-legged frogs (Rana aurora) and northwestern salamanders (Ambystoma gracile) from the Sumas Prairie. Egg masses were sampled from three agricultural sites that were exposed to agricultural runoff, and three reference sites that had lower agricultural runoff exposures. Not only was there little difference in contamination between agricultural and reference sites, but the levels of pesticides and PCBs found were lower than the concentrations reported to cause developmental or behavioural problems in amphibians. 相似文献