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151.
152.
153.
Current “business as usual” projections suggest greenhouse gas emissions from industrialized nations will grow substantially
over the next decade. However, if it comes into force, the Kyoto Protocol will require industrialized nations to reduce emissions
to an average of 5% below 1990 levels in the 2008–2012 period. Taking early action to close this gap has a number of advantages.
It reduces the risks of passing thresholds that trigger climate change “surprises.” Early action also increases future generations'
ability to choose greater levels of climate protection, and it leads to faster reductions of other pollutants. From an economic
sense, early action is important because it allows shifts to less carbon-intensive technologies during the course of normal
capital stock turnover. Moreover, many options for emission reduction have negative costs, and thus are economically worthwhile,
because of paybacks in energy costs, healthcare costs, and other benefits. Finally, early emission reductions enhance the
probability of successful ratification and lower the risk of noncompliance with the protocol. We discuss policy approaches
for the period prior to 2008. Disadvantages of the current proposals for Credit for Early Action are the possibility of adverse
selection due to problematic baseline calculation methods as well as the distributionary impacts of allocating a part of the
emissions budget already before 2008. One simple policy without drawbacks is the so-called baseline protection, which removes
the disincentive to early action due to the expectation that businesses may, in the future, receive emission rights in proportion
to past emissions. It is particularly important to adopt policies that shift investment in long-lived capital stock towards
less carbon-intensive technologies and to encourage innovation and technology development that will reduce future compliance
costs. 相似文献
154.
Françoise Muller Sophie Dreux Jean-François Oury Dominique Luton Serge Uzan Michèle Uzan Michel Levardon Marc Dommergues 《黑龙江环境通报》2002,22(11):1001-1004
Women having access to prenatal care late in pregnancy may still wish to benefit from maternal serum screening for Down syndrome. Therefore, we established reference values for α-feto protein (AFP) and free β-human chorionic gonadotrophin (β-hCG), and assessed the diagnostic value of maternal serum marker screening at 18–35 weeks' gestation based upon a series of 4072 sera from unaffected pregnancies and 118 sera from pregnant women with fetuses affected by Down syndrome. Using a 1/250 risk cut-off, a detection rate of 72.9% (95% CI = 71.5–74.3%) was achieved with a false-positive rate of 7.51% (95% CI = 6.71–8.3%). This was not significantly different from the percentages observed in our 14–17 weeks routine screening (50 596 patients): 71.9% (95% CI = 71.5–72.3%) and 6.48% (95% CI = 6.28–6.68%), respectively. Detection and screen-positive rates were, respectively, 51.3% (95% CI = 35.6–67.0%) and 5.95% (95% CI = 5.12–6.68%) in women aunder 35 years of age, and 84.8% (95% CI = 76.9–92.7%) and 24% (95% CI = 20.7–27.3%) in women aged 35 years and over. In conclusion, maternal serum marker screening is feasible at 18 weeks' gestation and later, which may be of interest in selected cases. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
155.
青海省牧区雪灾预警模型研究 总被引:4,自引:0,他引:4
对青海省牧区各气象站的积雪深度、积雪日数等气象资料进行了统计分析,结合青海省牧区积雪状况和草场特点,建立了雪灾预警模型。 相似文献
156.
William J. de Groot Robert D. Field Michael A. Brady Orbita Roswintiarti Maznorizan Mohamad 《Mitigation and Adaptation Strategies for Global Change》2007,12(1):165-180
Forest and land fires in Southeast Asia have many social, economic, and environmental impacts. Tropical peatland fires affect
global carbon dynamics, and haze from peat fires has serious negative impacts on the regional economy and human health. To
mitigate these fire-related problems, forest and land management agencies require an early warning system to assist them in
implementing fire prevention and management plans before fire problems begin. Fire Danger Rating Systems (FDRS) were developed
for Indonesia and Malaysia to provide early warning of the potential for serious fire and haze events. In particular, they
identify time periods when fires can readily start and spread to become uncontrolled fires and time periods when smoke from
smouldering fires will cause an unacceptably high level of haze. The FDRS were developed by adapting components of the Canadian
Forest Fire Danger Rating System, including the Canadian Forest Fire Weather Index (FWI) System and the Canadian Forest Fire
Behavior Prediction (FBP) System, to local vegetation, climate, and fire regime conditions. A smoke potential indicator was
developed using the Drought Code (DC) of the FWI System. Historical air quality analysis showed that the occurrence of severe
haze events increased substantially when DC was above 400. An ignition potential indicator was developed using the Fine Fuel
Moisture Code (FFMC) of the FWI System. Historical hot spot analysis, grass moisture, and grass ignition studies showed that
fire occurrence and the ability for grass fires to start and spread dramatically increased when FFMC > 82. The Initial Spread
Index (ISI) of the FWI System was used to develop a difficulty of control indicator for grassland fires, a fuel type that
can exhibit high rates of spread and fire intensity. This ISI-based indicator was developed using the grass fuel model of
the FBP System, along with a standard grass fuel load and curing level estimated from previous Indonesian studies. Very high
fire intensity is expected in grasslands when ISI ≥ 6. To provide early warning, the FDRS identifies classes of increasing
fire danger as the FFMC, DC, and ISI approach these key threshold values. The Indonesian FDRS is now operated nationally at
the Indonesian Meteorological and Geophysical Agency. The Malaysian Meteorological Service operates the Malaysian FDRS and
displays regional outputs for the Association of Southeast Asian Nations. The FDRS are being used by forestry, agriculture,
environment, and fire and rescue agencies to develop and implement fire prevention, detection, and suppression plans. 相似文献
157.
Karin Sundberg MD Steen Smidt-Jensen Claes Lundsteen Kirsten Agerbæk John Philip 《黑龙江环境通报》1993,13(12):1101-1110
Due to the low cell concentration, cultures from early amniotic fluid specimens usually require 2–3 weeks in culture prior to karyotyping. The purpose of this study was to evaluate the culture quality of amniotic fluid cells from early pregnancy, obtained by a new filter technique. The hypothetical advantage of the technique was that the increased cell yield might reduce the culture time before karyotyping. Culture quality was assessed by the number of colonies, the percentage of colonies containing mitoses in filter and control cultures, and the culture time. The setting was a consecutive clinical trial. One hundred samples were obtained from ongoing pregnancies at 11–14 weeks of gestation (mean 12·8 weeks). By circulating a mean of 26 ml of amniotic fluid through a cell filter system leading the cell-free fluid back to the amniotic cavity, the cell yield was increased in the sample of 7 ml corresponding to the dead space of the filter system. The culture results were compared with control cultures from 5 ml samples drawn from the same pregnancies prior to recirculation. The cultures from the first flushing of the filter system yielded 2·6 times more colonies and in total 4·2 times more colonies were found in the three cultures grown from each filter sample when compared with the control cultures. Moreover, the filter cultures showed significantly more colonies with mitoses. The mean culture time was 8·0 days for the filter cultures, from which the karyotypes were analysed. The controls would have needed more time in culture to fulfil the diagnostic criteria for karyotyping. One case of 47,XY, + 21 was found; the rest had normal karyotypes. We conclude that the filter technique improves the culture quality of early amniotic fluid samples and allows early arrest of the cultures. 相似文献
158.
The authors report on a series of 210 chorion villus sampling diagnoses made with a needle by the transabdominal route. The rate of fetal loss was 4·2 per cent. Placental localization was important: fetal losses were 8 per cent when the placenta was strictly posterior (transamniotic route), whereas it was only 1·6 per cent when it was not posterior. Moreover, all fetal losses occurred (apart from one at 12·5 weeks of amenorrhea) before the 12th week of amenorrhea. The authors suggest that choriocentesis by the transabdominal route should not be performed before the 12th week of amenorrhea, and that the amniotic membrane should not be disturbed before the 13th week of amenorrhea. 相似文献
159.
Separately identified samples of amniotic fluid and extraembryonic coelomic fluid obtained by high resolution transvaginal ultrasound-guided amniocentesis from 32 women between 7 and 12 weeks of pregnancy were analysed for human chorionic gonadotrophin (hCG) and alpha-fetoprotein (AFP). There was a highly significant difference between the hCG levels in amniotic fluid (median level 6.3 U/ml; range 1.6–310.0 U/ml) and those in extraembryonic coelomic fluid (median level 400.0U/ml; range 135.0–2250.0U/ml) (p<0.001; Mann-Whitney U/–test). The levels of AFP were very similar in amniotic fluid (median 26.0 kU/ml; range 10.0–116.5 kU/ml) and extraembryonic coelomic fluid (median level 24.1 kU/ml; range 12.4–94.4 kU/ml). 相似文献
160.
Fetal nuchal translucency was measured at 11–14 weeks' gestation in 97 pregnancies referred for early amniocentesis for advanced maternal age. The nuchal translucency was abnormal in 11 fetuses and the fetal karyotype was abnormal in five of these 11 cases. The karyotype was normal in 86 cases with normal nuchal translucency. The culture failure and miscarriage rates associated with early amniocentesis were 3·3 per cent and 2·2 per cent respectively. Amniotic fluid leakage occurred in 6 per cent of cases. In women requesting fetal karyotyping for advanced maternal age without additional biochemical screening, fetal nuchal translucency should be measured at 11–14 weeks. If the nuchal thickness is ≥ 3 mm, a first-trimester diagnostic procedure is indicated; however, if it is <3 mm, amniocentesis should be delayed until 16 weeks' gestation. 相似文献