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51.
At present, dynamic land use, climate change, and growing needs for fresh water are increasing the demand on the ecosystem effects of forest vegetation. Mountainous areas are at the forefront of scientific interest in European forest ecology and forest hydrology. Although uplands cover a significant area of the Czech Republic and other countries and are often covered with forest formations, they do not receive an appropriate amount of attention. Therefore, two experimental upland head micro-watersheds in the Bohemian Massif were selected for study because they display similar natural conditions, but different vegetative conditions (forest versus meadow). During the 2011 growing season, short-term streamflow measurements were carried out at the discharge profiles of both catchments and were evaluated in relation to climatic data (rainfall and temperature). The basic premise was that the streamflow in a forested catchment must exhibit different temporal dynamics compared to that in treeless areas and that these differences can be attributed to the effects of woody vegetation. These conclusions were drawn from measurements performed during dry periods lasting several days. A decreasing streamflow trend during the day part of the day (0900–1900 hours) was observed in both localities. The decrease reached approx. 44 % of the initial morning streamflow (0.24 dm3 s?1 day?1) in the treeless catchment and approx. 20 % (0.19 dm3 s?1 day?1) in the forested catchment. At night (1900–0900 hours), the streamflow in the forested catchment increased back to its initial level, whereas the streamflow in the treeless catchment stagnated or slowly decreased. We attribute these differences to the ecosystem effects of woody vegetation and its capacity to control water loss during the day. This type of vegetation can also function as a water source for the hydrographic network during the night. 相似文献
52.
Patrick Riefer Timm Klausmeyer Andreas SchäFfer Jan Schwarzbauer Burkhard Schmidt 《Journal of environmental science and health. Part. B》2013,48(5):394-403
Anthropogenic contaminants like nonylphenols (NP) are added to soil, for instance if sewage-sludge is used as fertilizer in agriculture. A commercial mixture of NP consists of more than 20 isomers. For our study, we used one of the predominate isomers of NP mixtures, 4-(3,5-dimethylhept-3-yl)phenol, as a representative compound. The aim was to investigate the fate and distribution of the isomer within soil and soil derived organo-clay complexes. Therefore, 14C- and 13C-labeled NP was added to soil samples and incubated up to 180 days. Mineralization was measured and soil samples were fractionated into sand, silt and clay; the clay fraction was further separated in humic acids, fulvic acids and humin. The organo-clay complexes pre-incubated for 90 or 180 days were re-incubated with fresh soil for 180 days, to study the potential of re-mobilization of incorporated residues. The predominate incorporation sites of the nonylphenol isomer in soil were the organo-clay complexes. After 180 days of incubation, 22 % of the applied 14C was mineralized. The bioavailable, water extractable portion was low (9 % of applied 14C) and remained constant during the entire incubation period, which could be explained by an incorporation/release equilibrium. Separation of organo-clay complexes, after extraction with solvents to release weakly incorporated, bioaccessible portions, showed that non-extractable residues (NER) were preferentially located in the humic acid fraction, which was regarded as an effect of the chemical composition of this fraction. Generally, 27 % of applied 14C was incorporated into organo-clay complexes as NER, whereas 9 % of applied 14C was bioaccessible after 180 days of incubation. The re-mobilization experiments showed on the one hand, a decrease of the bioavailability of the nonylphenol residues due to stronger incorporation, when the pre-incubation period was increased from 90 to 180 days. On the other hand, a shift of these residues from the clay fraction to other soil fractions was observed, implying a dynamic behavior of incorporated residues, which may result in bioaccessibility of the NER of nonylphenol. 相似文献
53.
54.
Claudia S. Hak Mattias Hallquist Evert Ljungström Maria Svane Jan B.C. Pettersson 《Atmospheric environment (Oxford, England : 1994)》2009,43(15):2481-2488
A method for continuous on-road measurements of particle number emissions for both diesel- and petrol-fuelled vehicles is presented. The setup allows the determination of particle number emission factors on an individual vehicle basis by the simultaneous measurement of CO2 and particle concentrations. As an alternative to previous measurements on the kerbside, the sample is taken directly in the street, with the advantage of sampling in-situ within the exhaust plumes of passing vehicles, allowing the separation of the individual high-concentration plumes. The method was tested in two experiments that were conducted in the Gothenburg area. In the first study, which was performed at an urban roadside, we were able to determine particle emission factors from individual vehicles in a common car fleet passing the measurement site. The obtained emission factors were of the same order of magnitude (between 1.4 × 1012 and 1.8 × 1014 particles km?1) as values published in the recent literature for light duty vehicles. An additional on-road experiment was conducted at a rural road with four light duty reference vehicles (three of them petrol-powered and one diesel-powered) at driving speeds of 50 and 70 km h?1, realised with different engine speeds. The results of the traffic emission studies show that the method is applicable provided that instruments with an adequate dynamic range are used and that the traffic is not too dense. In addition, the variability in particle emissions for a specified driving condition was estimated. 相似文献
55.
A four-stage method of providing conditions for improving the stability of a landscape sector is presented. In the first stage,
structure and function of the landscape system is examined, predominantly based on the results of monitoring. In the second
stage, a method is suggested for applying monitoring data to a dynamic structure with complex functions of the territory under
examination. In the third stage, the territory is optimized as to the function of particular components within it. The optimization
consists in controlling the dynamics of the flows of material, energy, and population within the sector. In the fourth stage,
the holistic function of the landscape strip should be monitored with respect to representative key factors. The entire concept
is based on assuming the existence of destabilizing processes leading to ecocritical situations and determining mitigating
factors using heuristic methods of optimization. 相似文献
56.
Four broad classes of dependent variables (psychological strain, physical illness symptoms, health-related behaviour and social participation) were associated with eleven categories of stressors and stress moderators from work and family life, using multiple logistic regression analysis for a random sample of 8700 full-time male and female members of T.C.O., a major Swedish white-collar labour federation (covering 25 per cent of the Swedish labour force). Our goal was to find broad patterns of associations by comparing relative magnitudes of effects for (a) stressors and stress moderators; (b) work and family activities, and (c) males and females. Fifty per cent of the associations between environmental factors and dependent variables were significant in the predicted direction at the 5 per cent level. However, only 5 per cent of the associations are as strong, for example, as average smoking/heart disease associations. Our primary conclusion is that job factors are the next strongest set of predictors of health and behaviour after age. Job factors are stronger than family factors for both men and women; proportionally increasing the explained variance by over 60 per cent versus roughly 20 per cent for family factors (over the 25 per cent of explanation due to demographic factors). The overall pattern of stressor/outcome associations is quite similar for men and women, although both job/outcome and family burden/outcome associations are stronger for women than for men. We failed to find a clear linkage between particular stressors and particular physical illnesses. Among the job factors, control and work load have the strongest associations; with the former predicting behaviour patterns and job satisfaction (along with social support), and the latter predicting mental strain symptoms. Family problems are associated with increased health risks (stronger for men) and family responsibilities and constraints affect health behaviour (stronger for women). Job satisfaction is the most successfully predicted outcome in the study, and is similarly affected for men and women. 相似文献
57.
Jan Narveson 《Journal of Agricultural and Environmental Ethics》1995,8(2):145-156
Environmental Ethics is the ethics of how we humans are to relate to each other about the environment we live in. The best way to adjust inevitable differences among us in this respect is by private property. Each person takes the best care of what he owns, and ownership entails the free market, which enables people to make mutually advantageous trades with those who might use it even better. Public regulation, by contrast, becomes management in the interests of the regulators, or of special interests, such as lovers of rare species-not the people they're supposed to be serving. 相似文献
58.
Jan Cademartori 《Natural resources forum》2002,26(1):27-44
The desert mining region of Antofagasta, Chile, enjoyed spectacular economic growth in the 1990s as a result of foreign direct investment (FDI), mainly in the exploitation of the region's rich copper deposits. In a country considered by international financial institutions to be a good example of economic performance, Antofagasta has been termed a model region,and Chile's economic and social development in the 1990s has been considered a suitable model for other Latin American countries. However, development indices based on statistical data must be examined with caution, as human welfare does not necessarily keep pace with economic growth. This article analyses the Antofagasta Region in terms of problems that may occur in conjunction with accelerated economic growth, and how these can affect the environment, as well as the regional labour market. The article also examines a regional economic strategy for Antofagasta recently proposed by the local government, and suggests new alternatives for the sustainable economic development of the region. 相似文献
59.
Anthony L. Andrady Jan E. Pegram Shuji Nakatsuka 《Journal of Polymers and the Environment》1993,1(1):31-43
Studies on three types of enhanced photodegradable polyethylenes showed tensile elongation at break to be a suitable parameter for assessing disintegration due to outdoor weathering. Disintegration rates varied greatly with exposure location, with Arizona the harshest environment and Washington and New Jersey the mildest. The rate of breakdown of the enhanced degradable polyethylenes relative to unmodified plastic was termed an enhancement factor. For the materials studied, average enhancement factors generally ranged from five to fifteen. The location-dependent variability in rate parameters can be mostly explained in terms of different average radiation levels and temperatures at these locations. A duplicate exposure protocol was developed to determine if the test data were complicated by short-term fluctuations in sunlight or temperature during exposure. 相似文献
60.
A reproductive-health knowledge, attitudes and practices (KAP) survey was carried out among 468 Afghan women of reproductive age. A convenience sample of women was selected from attendees in the outpatient departments of four health facilities in Kabul. Seventy-nine per cent of respondents had attended at least one antenatal consultation during their last pregnancy. Two-thirds (67 per cent) delivered their first child between 13 and 19 years. The Caesarean-section rate was low (1.6 per cent). Two-thirds (67 per cent) of deliveries occurred in the home. The contraceptive prevalence rate was 23 per cent (16 per cent modern and 7 per cent natural methods). Twenty-four per cent had knowledge of any STIs, although most of these women did not know correctly how to prevent them. Most of the women (93 per cent) needed authorization from their husband or a male relative before seeking professional health-care. In multivariate analysis, women's schooling was significantly associated with antenatal-care attendance (AOR 4.78), institutional delivery (AOR 2.29), skilled attendance at birth (AOR 2.07) and use of family planning (AOR 4.59). Reproductive-health indicators were noted to be poor even among these women living in Kabul, a group often considered to be the most privileged. To meet the reproductive-health needs of Afghan women, the socio-cultural aspects of their situation--especially their decision-making abilities -- will need to be addressed. A long-standing commitment from agencies and donors is required, in which the education of women should be placed as a cornerstone of the reconstruction process of Afghanistan. 相似文献