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91.
This paper examines various health effects of photochemical air pollution in Japan, primarily through the review of epidemiological studies. Health effects discussed include subjective respiratory symptoms, respiratory function testing, ocular effects, and hospital diagnostic tests. The downward trend in oxidant cautions and paralleled health effects, as reported by the Japanese Environmental Agency, are discussed. The methods determined by Japanese ordinance for measurement of oxidants, SO2, NO x , and CO are described.  相似文献   
92.
Abstract: Terrestrial salamanders of the family Plethodontidae have unique attributes that make them excellent indicators of biodiversity and ecosystem integrity in forested habitats. Their longevity, small territory size, site fidelity, sensitivity to natural and anthropogenic perturbations, tendency to occur in high densities, and low sampling costs mean that counts of plethodontid salamanders provide numerous advantages over counts of other North American forest organisms for indicating environmental change. Furthermore, they are tightly linked physiologically to microclimatic and successional processes that influence the distribution and abundance of numerous other hydrophilic but difficult-to-study forest-dwelling plants and animals. Ecosystem processes such as moisture cycling, food-web dynamics, and succession, with their related structural and microclimatic variability, all affect forest biodiversity and have been shown to affect salamander populations as well. We determined the variability associated with sampling for plethodontid salamanders by estimating the coefficient of variation (CV ) from available time-series data. The median coefficient of variation indicated that variation in counts of individuals among studies was much lower in plethodontids (27%) than in lepidoptera (93%), passerine birds (57%), small mammals (69%), or other amphibians (37–46%), which means plethodontid salamanders provide an important statistical advantage over other species for monitoring long-term forest health.  相似文献   
93.
Abstract: Different deforestation agents, such as small farmers and large agricultural businesses, create different spatial patterns of deforestation. We analyzed the proportion of deforestation associated with different‐sized clearings in the Brazilian Amazon from 2002 through 2009. We used annual deforestation maps to determine total area deforested and the size distribution of deforested patches per year. The size distribution of deforested areas changed over time in a consistent, directional manner. Large clearings (>1000 ha) comprised progressively smaller amounts of total annual deforestation. The number of smaller clearings (6.25–50.00 ha) remained unchanged over time. Small clearings accounted for 73% of all deforestation in 2009, up from 30% in 2002, whereas the proportion of deforestation attributable to large clearings decreased from 13% to 3% between 2002 and 2009. Large clearings were concentrated in Mato Grosso, but also occurred in eastern Pará and in Rondônia. In 2002 large clearings accounted for 17%, 15%, and 10% of all deforestation in Mato Grosso, Pará, and Rondônia, respectively. Even in these states, where there is a highly developed agricultural business dominated by soybean production and cattle ranching, the proportional contribution of large clearings to total deforestation declined. By 2009 large clearings accounted for 2.5%, 3.5%, and 1% of all deforestation in Mato Grosso, Pará, and Rondônia, respectively. These changes in deforestation patch size are coincident with the implementation of new conservation policies by the Brazilian government, which suggests that these policies are not effectively reducing the number of small clearings in primary forest, whether these are caused by large landholders or smallholders, but have been more effective at reducing the frequency of larger clearings.  相似文献   
94.
“Rules of thumb” for stack design have been developed for use on problems where extensive studies cannot be justified or where quantitative design data are unavailable. The application of these rules to a practical stack design problem is discussed. The IBM 704 computer has been used for rapid yet rigorous stack design studies. The computer procedures for design are discussed and its application to a practical problem is described in detail.  相似文献   
95.
As a consequence of the accumulation of anthropogenic Pb in upland catchments, there has been much recent concern about the potential mobilisation and transport of Pb from the soils to receiving waters and also the possible harmful effects that this might have on aquatic biota. This paper presents the findings of a two-year study of Pb behaviour in an organic-rich upland catchment at Glensaugh in NE Scotland. Pb inputs to the catchment were characterised by direct measurements of Pb concentration and (206)Pb/(207)Pb ratios in rain water and interception. Pb outputs from the catchment were calculated from measurements on stream water samples taken from the two main streams, the Cairn Burn and Birnie Burn. The relative contribution of Pb from groundwater and throughflow, under different flow conditions (base flow and high flow), to stream waters was investigated via analysis of springs sourced from groundwater and of waters flowing through the various soil horizons (S (surface), A, B, C, and D), respectively. The outcome of intensive sampling and analysis over the two-year time period was that, even with marked reduction in Pb inputs over the past two decades, the catchment was still acting as a net sink for the current atmospheric deposition. Although the Pb isotopic signature for stream water is very similar to that for the contemporaneous rain water ((206)Pb/(207)Pb approximately 1.15-1.16), only a small portion of the rain water is transferred directly to stream water. Instead, the Pb input is transferred to the stream waters mainly via groundwater and it was also confirmed that the latter had a similar Pb isotopic signature. From the Pb isotopic measurements on throughflow waters, however, Pb being removed via the streams contained some previously deposited Pb, i.e. mobilisation of a small portion of soil-derived anthropogenic Pb was occurring. These findings are important not only with respect to the source/sink status of the catchment but also for calculation of the extent of retention of the current atmospheric Pb inputs, which must take account of the release of previously deposited Pb from the catchment soils, a process occurring mainly under high flow conditions.  相似文献   
96.
Simple bioenergetics models were used to derive annual nitrogen excretion rates of each seabird species occurring at colonies in the UK. These were combined with population distribution data and an estimated fraction of nitrogen volatilized to estimate the spatial distribution of NH3 emissions from seabird colonies at a 1 km resolution. The effect of these emissions on atmospheric NH3 concentrations and nitrogen deposition in the UK was assessed using the FRAME atmospheric chemistry and transport model. The total emission of NH3 from the UK seabird colonies is estimated at 2.7 kt yr?1. Emissions from seabirds are largely concentrated in remote parts of Britain, where agricultural and other anthropogenic emissions are minimal. Although seabirds account for less than 1% of total UK NH3 emissions (~370 kt yr?1), their occurrence in remote areas and frequently large colony sizes results in seabirds providing a major fraction of the atmospheric nitrogen deposition for many remote ecosystems.  相似文献   
97.
Taxodium distichum (L.) Rich.]. The study site, a swamp in St. Martin Parish, Louisiana, has received municipal wastewater for the last 40 years. Growth chronologies from 1920 to 1992 were developed from cross-dated tree core samples taken from treated and control sites with similar size and age classes. Mean diameter increment (DINC) and mean basal area increment (BAI) chronologies were constructed separately for each stand. These chronologies were then summarized by tree and stand into seven nine-year intervals resulting in three pretreatment intervals from 1926 to 1952 and four treatment intervals from 1953 to 1988. Significant differences in growth response between sites showed a consistent pattern of growth enhancement in the treated site coincident with the onset of effluent discharge. The ratio of treated to control baldcypress growth rates (computed from DINC) averaged 0.74 during the pretreatment period and 1.53 during the treatment period. Over the period of study, control DINC decreased from 77 mm to 29 mm/nine-year interval, while treatment DINC increased slightly from 40 mm to 47 mm/nine-year interval. Control BAI did not increase significantly and averaged 192 cm2/nine-year interval. There was a significant increase in treatment BAI from 129 to 333 cm2/nine-year interval over the period of record. These results clearly demonstrate sustained long-term baldcypress growth enhancement throughout 40 years of municipal effluent discharge.  相似文献   
98.
Trisorny 18 mosaicism was found in multiple primary cultures of amniotic fluid cells and subsequently confirmed by chromosome analysis of several tissues derived from the aborted fetus. The overall frequency of the minority cell line was 25 per cent in the amniotic fluid cultures and 28 per cent in the fetal tissues although much intertissue variations were noted.  相似文献   
99.
A 48,XXYY fetus was diagnosed prenatally in a 34-year old female who was seen at 18-5 weeks of pregnancy for genetic counselling and amniocentesis for advanced maternal age. The pregnancy was terminated, and skin and peripheral blood samples were obtained at the time of delivery. These samples also exhibited the 48,XXYY chromosomal complement.  相似文献   
100.
Abstract:  The 735,000-km2 Caatinga is a mosaic of thorn scrub and seasonally dry forests, with more than 2000 species of vascular plants, fishes, reptiles, amphibians, birds, and mammals. Endemism in these groups varies from 7% to 57%. Inappropriate land use has already caused serious environmental damage and accelerating desertification, which is currently threatening about 15% of the region. Moreover, the rich and diversified biota of the Caatinga is poorly protected: only 11 reserves (<1% of the region) are strictly protected areas. A conservation strategy for the Caatinga biota should be designed to (1) avoid further habitat loss and desertification, (2) maintain key ecological services necessary for improving the living standards of the rural population, and (3) promote the sustainable use of the region's natural resources. Implementing an effective conservation agenda for the Caatinga is not an easy task but, with creativity and consistent financial support, it should be possible to nurture this unique biome and guarantee the preservation of its rich and diversified fauna and flora, and, with this, the well-being of its rural populations.  相似文献   
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