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711.
Hans Schreier Sandra Brown Margaret Schmidt Pravakar Shah Bubhan Shrestha Gopal Nakarmi Khagendra Subba Susanne Wymann 《Environmental management》1994,18(1):139-150
GIS overlay techniques were used to provide a quantitative historic documentation of deforestation and land-use dynamics in
the Middle Mountains of Nepal between 1947 and 1990. Deforestation was most critical in the 1960s, but active afforestation
programs in the 1980s have reversed the process. In spite of these trends, the degradation problem is more complex. The GIS
evaluation showed that 86% of the recently afforested land is now under pine plantations located primarily at lower elevations
and moderately steep slopes. In contrast, rainfed agricultural expansion is most pronounced on acidic soils and steeper, upper
elevation sites, suggesting marginalization of agriculture. Agricultural expansion coupled with major losses of grazing land
to pine forests are the key processes pointing towards major animal feed deficits. An alternative animal feed source is suggested
through GIS using a topographically based microclimatic classification to generate a tree-planting map where the optimum ecological
conditions for selective native fodder tree species are identified. 相似文献
712.
Paul Tyler Craig M. Young Emily Dolan Shawn M. Arellano Sandra D. Brooke Maria Baker 《Marine Biology》2007,150(5):829-840
The gametogenic periodicity of the cold seep mussel “Bathymodiolus” childressi was analysed from a time series of samples from depths of ∼ 650 m surrounding the Brine Pool cold seep on the continental
slope of the northern Gulf of Mexico. Occasional samples were retrieved from Bush Hill and GC 234 for comparison. At the Brine
Pool, both females and males showed strong reproductive periodicity with the initiation of gametogenesis from December to
March, followed by a period of gamete growth or proliferation and spawning from October to February. Gametogenesis was synchronized
at all three sites. Gametogenic periodicity appears to be correlated with surface production that peaks during the winter
months. Downward flux of detritus during this period may provide food for the planktotrophic larvae and also supplementary
nutrition for the adult, which has chemosynthetic bacterial symbionts but is also capable of filter feeding. Individuals in
all three populations carried parasites and these were especially common at Bush Hill and GC234, where it is suggested they
have a major impact on reproductive output. 相似文献
713.
714.
Patterns of nine intracellular free amino acids (FAA), which are utilized as organic osmolytes for salinity-induced cell volume regulation in marine osmoconformers, were compared in five Macoma balthica populations and seven Mytilus spp. populations along their European distribution. Three types of FAA patterns were classified within both taxa: a northern Baltic type, a southern Baltic type and an Atlantic/Mediterranean type which mainly differ regarding the share of alanine and taurine. Differences are discussed in relation to habitat salinity and population genetics. Along a salinity gradient, the total size of the intracellular FAA pool did not differ between sympatric M. balthica and Mytilus spp., and was significantly correlated with habitat osmolality in a range from 70 to 600 mmol kg−1 H2O (oligohaline to mesohaline) in both bivalves. In M. balthica, this correlation was mainly based on significant correlations of alanine (15–100 mmol kg−1 DW), glycine (30–100 mmol kg−1 DW) and taurine (0–70 mmol kg−1 DW) with habitat osmolality. In Mytilus spp., only glycine (25–100 mmol kg−1 DW) and taurine (4–180 mmol kg−1 DW) were significantly correlated with habitat osmolality. The concentration of alanine was three times lower in Mytilus spp. than in M. balthica and did not correlate with habitat osmolality. Within a habitat osmolality range from 600 to 1,100 mmol kg−1 H2O (mesohaline to marine) the concentration of FAA remained constant in both taxa. It is suggested that under marine conditions additional organic osmolytes must become more important for cell volume regulation in Macoma and Mytilus. 相似文献
715.
Bloomfield Janine Ratchford Marina Brown Sandra 《Mitigation and Adaptation Strategies for Global Change》2000,5(1):3-8
Mitigation and Adaptation Strategies for Global Change - 相似文献
716.
Vesna K. Spasojević Brkić Zorica A. Veljković Tamara Golubović Aleksandar Dj. Brkić Ivana Kosić Šotić 《International journal of occupational safety and ergonomics》2016,22(2):228-240
Procedures in the development process of crane cabins are arbitrary and subjective. Since approximately 42% of incidents in the construction industry are linked to them, there is a need to collect fresh anthropometric data and provide additional recommendations for design. In this paper, dimensioning of the crane cabin interior space was carried out using a sample of 64 crane operators’ anthropometric measurements, in the Republic of Serbia, by measuring workspace with 10 parameters using nine measured anthropometric data from each crane operator. This paper applies experiments run via full factorial designs using a combined traditional and Taguchi approach. The experiments indicated which design parameters are influenced by which anthropometric measurements and to what degree. The results are expected to be of use for crane cabin designers and should assist them to design a cabin that may lead to less strenuous sitting postures and fatigue for operators, thus improving safety and accident prevention. 相似文献
717.
Rada D. Đurović Tijana M. Đorđević 《Journal of environmental science and health. Part. B》2013,48(9):851-857
The influence of organic matter and clay contents on headspace solid phase microextraction (HS-SPME) determination of triazine and organophosphorus pesticides in different soils was studied. The results of the study showed that content of soil organic matter dominantly participated in sorption of triazines (simazine, atrazine and prometryn) to soil, while sorption of organophosphorus pesticides (phorate and tebupirimfos) could not be explained only by contents of dominant soil sorption components (soil organic matter and clay). Sorption of all pesticides studied to different soil types was similar at their lower concentrations while the influence of soil composition was expressed at higher concentration levels. Except for phorate, the obtained sorption trends were different from those obtained by direct SPME mode (DM-SPME) and exhaustive liquid-solid extraction (LSE) method. These results indicated that most likely co-extractants from the analyzed medium complicated evaporation and diffusion of the pesticides to the PDMS fiber during HS-SPME sampling. 相似文献
718.
Velimir Pravdić 《Chemistry and Ecology》2013,29(1-2):25-31
Abstract Prevention of marine pollution, particularly in semi-enclosed seas, embayments and areas with limited exchange of water, requires a well conceived and harmonized legal system, specified standards, a monitoring programme, and effective control and enforcement capabilities. This comprehensive approach is often called a strategy. Three generations of strategies have been devised and applied historically in Europe and North America, each a step further in integrating environmental protection, technical advancement and economic capabilities. the overpowering socio-economic problems of transition from a centrally planned to a market economy, a task facing a dozen central and eastern European coastal states, compound the problem of application of an integrated approach. No management strategy can achieve its set goals unless based on scientific evidence. the data base has to offer information on two basic questions, one specific and one of a general nature. The specific question is: Has the area under consideration some features, an activity, or one or more living species, which must be protected at any cost? the answer to this question will invoke the precautionary principle into strategic considerations, and leads to the general question: What is the carrying (= assimilative or environmental) capacity for each activity and for the discharge of each contaminant into the impacted area? Answers to these questions lead to the choice of the strategy for environmental management. 相似文献
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