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31.
This paper examines whether corporate financial performance is affected by public endorsement of environmental and social performance. Event study methodology, which relies on the notion of market efficiency, is used to examine the relationship between positive and negative announcements and changes in share prices or daily returns. Inclusion in and deletion from the FTSE4Good UK Index is used as a proxy measure for good (poor) corporate social responsibility. The abnormal or unexpected daily returns associated with an event are calculated and their significance tested. The results show a trend towards positive and negative announcements having the expected effects on daily returns. But these movements are not significant and the data do not suggest that a firm's presence on the index brings it any significant financial return for signalling its corporate social responsibility.  相似文献   
32.
This review article discusses prenatal screening and diagnosis of neural tube defects (NTD). High detection rates occur in countries operating ultrasound screening programmes because classical two-dimensional ultrasound cranial signs (lemon shaped head, banana cerebellum, ventriculomegaly) are important diagnostic clues to the presence of spina bifida. Careful evaluation of both the spine and a search for other abnormalities is warranted. Important prognostic information for spina bifida relates to the lesion level, with a “watershed” between L3 and L4 marking a very high chance of being wheelchair bound with the higher lesions. Three-dimensional ultrasound using multiplanar views can achieve diagnostic accuracy within one vertebral body in around 80% of patients. There are high rates of pregnancy termination for spina bifida in many European countries, but the use of new imagining techniques allow better prediction of outcome, and consequently a refinement of prenatal counselling. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
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A harmonized comparative performance evaluation of A Unified Regional Air-quality Modelling System (AURAMS) v1.3.1b and Community Multiscale Air Quality (CMAQ) v4.6 air-quality modelling systems was conducted on the same North American grid for July 2002 using the same emission inventories, emissions processor, and input meteorology.Comparison of AURAMS- and CMAQ-predicted O3 concentrations against hourly surface measurement data showed a lower normalized mean bias (NMB) of 20.7% for AURAMS versus 46.4% for CMAQ. However, AURAMS and CMAQ had more similar normalized mean errors (NMEs) of 46.9% and 54.2%, respectively. Both models did similarly well in predicting daily 1-h O3 maximums; however, AURAMS performed better in calculating daily minimums. CMAQ's poorer performance for O3 is partly due to its inability to correctly predict nighttime lows.Total PM2.5 hourly surface concentration was under-predicted by both AURAMS and CMAQ with NMBs of ?10.4% and ?65.2%, respectively. However, as with O3, both models had similar NMEs of 68.0% and 70.6%, respectively. In general, AURAMS performance was better than CMAQ for all major PM2.5 species except nitrate and elemental carbon. Both models significantly under-predicted total organic aerosols (TOAs), although the mean AURAMS concentration was over four times larger than CMAQ's. The under-prediction of TOA was partly due to the exclusion of forest-fire emissions. Sea-salt aerosol made up approximately 50.2% of the AURAMS total PM2.5 surface concentration versus only 6.2% in CMAQ when averaged over all grid cells. When averaged over land cells only, sea-salt still contributed 13.9% to the total PM2.5 mass in AURAMS versus 2.0% in CMAQ.  相似文献   
35.
Many small watersheds and streams in the Brazilian Amazon have been impacted by agriculture and urban development, often due to household economic needs and migration processes. This study examined the relationships between land use, soil type, and household factors on stream water chemistry in and near the city of Altamira, Pará, Brazil, in 2008–2009. While soil weathering and stream discharge may have affected several stream water ion concentrations, agriculture and especially urban development were associated with high dissolved nitrogen concentrations, high water temperatures, and low dissolved oxygen concentrations in streams. Younger interviewed households were generally associated with these watersheds, and many urban residents reported disposing of household waste directly into streams. In contrast, older households were generally associated with forest and cocoa agriculture, along with lower water temperatures and higher dissolved oxygen concentrations in streams. These conditions persisted despite reported uses of herbicides and fertilizers by some residents.  相似文献   
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Moran EV  Clark JS 《Ecology》2012,93(5):1082-1094
Inequality in reproductive success has important implications for ecological and evolutionary dynamics, but lifetime reproductive success is challenging to measure in long-lived species such as forest trees. While seed production is often used as a proxy for overall reproductive success, high mortality of seeds and the potential for trade-offs between seed number and quality draw this assumption into question. Parentage analyses of established seedlings can bring us one step closer to understanding the causes and consequences of variation in reproductive success. In this paper we demonstrate a new method for estimating individual seedling production and average percentage germination, using data from two mixed-species populations of red oaks (Quercus rubra, Q. velutina, Q. falcata, and Q. coccinea). We use these estimates to examine the distribution of female reproductive success and to test the relationship between seedling number and individual seed production, age, and growth rate. We show that both seed and seedling production are highly skewed, roughly conforming to zero-inflated lognormal distributions, rather than to the Poisson or negative-binomial distributions often assumed by population genetics analyses. While the number of established offspring is positively associated with mean annual seed production, a lower proportion of seeds from highly fecund individuals become seedlings. Our red oak populations also show evidence of trade-offs between growth rate and reproductive success. The high degree of inequality in seedling production shown here for red oaks, and by previous studies in other species, suggests that many trees may be more vulnerable to genetic drift than previously thought, if immigration in limited by fragmentation or other environmental changes.  相似文献   
37.
Use of environmental valuation and benefits transfer in a recent legal ruling in the UK between Thames Water Utilities and the Environment Agency over water abstraction costs appeared to set an unfortunate precedent. In the first attempt to fulfil its statutory duties, the Agency was thwarted in its use and interpretation of non-market valuation techniques, in particular, the vexed issue of how to aggregate the results of valuation studies in original sites or those to where values might be transferred. The ruling has broader implications for water pricing and resource development by the industry. Far from being a blow for either cost-benefit analysis or environmental valuation, the decision highlights some of the research imperatives for the derivation of non-market values by economists and their translation for use in government decisions.  相似文献   
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Calcein as a marker in experimental studies newly-hatched gastropods   总被引:2,自引:0,他引:2  
A. L. Moran 《Marine Biology》2000,137(5-6):893-898
A nontoxic method of marking juvenile animals is a prerequisite for many field studies investigating growth and survivorship in marine invertebrates. This study investigates the effectiveness of low concentrations of calcein in marking hatchling snails (Nucella ostrina), the durability of the calcein mark, and the effects of marking on survivorship and growth. I also describe an inexpensive means of visualizing the calcein mark under a dissecting microscope. Results demonstrate that calcein provides a long-lasting, readily detected fluorescent shell mark that can be used to measure shell growth accurately. In addition, marking with calcein did not affect survivorship or growth, and had no size-dependent effects on growth or survivorship. Received: 13 October 1999 / Accepted: 18 June 2000  相似文献   
40.
Many long-lived radionuclides are present in groundwater at the Nevada Test Site (NTS) as a result of 828 underground nuclear weapons tests conducted between 1951 and 1992. In conjunction with a comprehensive geochemical review of radionuclides (3H, 14C, 36Cl, 99Tc and 129I) that are presumably mobile in the subsurface, we synthesized a body of radionuclide activity data measured from groundwater samples collected at 18 monitoring wells, to qualitatively assess their migration at the NTS over distances of hundreds of meters and over timescales of decades. Tritium and 36Cl showed little evidence of retardation, while the transport of 14C may have been retarded by its isotopic exchange with carbonate minerals in the aquifer. Observed local reducing conditions (either natural or test-induced) will impact the mobility of certain redox-sensitive radionuclides (especially 99Tc) that were otherwise soluble and readily transported under oxidizing conditions. Conversely, strongly oxidizing conditions may impact the mobility of 129I which is mobile under reducing conditions. The effect of iodine speciation on its transport deserves further attention. Indication of delayed transport of some “mobile” radionuclides (especially 99Tc) in the groundwater at the NTS suggested the importance of redox conditions of the natural system in controlling the fate and transport of radionuclides, which has implications in the enhanced performance of the potential Yucca Mountain repository, located adjacent to the NTS, to store high-level nuclear wastes as well as management of radionuclide contamination in legacy nuclear operations facilities.  相似文献   
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