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331.
Lee JK  Führ F  Kwon JW  Ahn KC 《Chemosphere》2002,49(2):173-181
In order to elucidate the long-term fate of the sulfonylurea herbicide cinosulfuron, the 14C-labelled chemical was applied to a clay loam soil, encased in two lysimeters, 22 days after rice (Oryza sativa L.) transplanting, and rice plants were grown for four consecutive years. Throughout the experimental period, leaching through soil profiles, absorption and translocation by rice plants, and distribution of 14C by downward movement in the soil layers were clarified. The total volume of leachates collected through the lysimeter soil over the four years amounted to 168 and 146 L in lysimeters I and II, respectively. The leachates contained 2.43% and 2.99% of the originally applied 14C-radioactivity, corresponding to an average concentration of 0.29 and 0.41 microg/L as the cinosulfuron equivalent in lysimeters I and II, respectively. The total 14C-radioactivity translocated to rice plants in the third and fourth year was 0.69% and 0.60% (lysimeter I), and 1.02% and 0.84% (lysimeter II) of the 14C applied, respectively. Larger amounts of cinosulfuron equivalents (0.54-0.75%) remained in the straw in the fourth year than in any other parts. The 14C-radioactivities distributed down to a depth of 70 cm after four years were 56.71-57.52% of the 14C applied, indicating the continuous downward movement and degradation of cinosulfuron in soil. The non-extractable residues were more than 88% of the soil radioactivity and some 45-48% of them was incorporated into the humin fraction. The 14C-radioactivity partitioned into the aqueous phase was nearly 30% of the extractable 14C, suggesting strongly that cinosulfuron was degraded into some polar products during the experimental period. It was found out in a supplemental investigation that flooding and constant higher temperature enhanced mineralization of [14C]cinosulfuron to 14CO2 in soil, indicating the possibility of chemical hydrolysis and microbial degradation of the compound in the flooded lysimeter soil.  相似文献   
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In many sexually dimorphic species adult sexes tend to segregate socially, spatially, or in habitat use. Several hypotheses have been formulated regarding underlying mechanisms. We investigated terrestrial habitat use and sexual segregation in a tropical otariid, the Galápagos sea lion (Zalophus californianus wollebaeki), where most of the hypotheses can be ruled out a priori. Factors relating to thermoregulation and costs of locomotion were of prime importance for habitat use. Habitats directly adjacent to the sea, with simple structured flat surfaces, shade, and tide pools were most frequented, but sexes and age classes differed in their usage patterns. Sexual segregation, both spatial and by habitat was pronounced in the reproductive period (RP), but remained high during the nonreproductive period (NRP). A GLM model of habitat use showed that in both seasons adult males frequented habitat types that adult females and other age classes used much less. Males were most abundant in suboptimal inland habitats, which offered only shade for cooling. Females with newborns differed in habitat use from females with older offspring and lone females. Spatial and habitat segregation are explained most parsimoniously as by-products of social processes, primarily intrasexual competition and female avoidance of male harassment, linked to the polygynous mating system.Electronic Supplementary Material Supplementary material is available in the online version of this article at and is accessible for authorized users.  相似文献   
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ABSTRACT: Utilizing predictions of pollutant movement generated by the CREAMS model, the economics of reducing field losses of sediment and nitrate percolation were compared between two soil types on each of two slopes common to the Upper Eastern Shore of Maryland. The soils considered were Matapeake silt loam and Sassafras sandy loam textures on field slopes of 3.5 percent and 7.5 percent. A representative cash grain farm was used as a basis of comparison. Under assumptions of profit maximization, economic optimal cropping systems varied by slope. Results further indicated that relative cost-effectiveness of sediment or nitrate percolation control varied by soil type for both slopes considered. Unit costs of sediment control were less on silt loam soils, while unit costs of nitrate percolation control were less on sandy loam soils.  相似文献   
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This review presents first ever literature survey on historical development of farm animal welfare indicators and assessment in the Danube region. This area, encompassing European Eastern countries and the Balkans, is to a large extent heterogeneous in terms of culture and language. However, international (English) publications were disproportionally small compared to the amount of research institutions and animal welfare activities present in the region. Therefore, the authors aimed at investigating the published literature, focusing on country level and on native languages. Data were collected for the 1980–2015 period referring to scientific papers published in international and national journals, papers and abstracts in proceedings of the international and national conferences, reviews, monographs, short communications, Ph.D., Master and Graduation theses. Welfare assessment of all farm animal species was observed including fish. Over 180 papers were in line with the preselected index. Data collected showed that publishing dynamics grew rapidly towards the last decade. Most of the studies were focused on animal welfare indicators such as stress, injuries and mutilations, behaviour, body condition and management practices. Cattle, chickens, pigs and sheep were the predominant species investigated. The study revealed that experts from the region were greatly involved in the studies of animal welfare indicators and assessment, contributing to development of the currently most widely used animal welfare assessment protocols, thus having an important role in animal welfare research and protection.  相似文献   
338.
Freshwater ecosystems are linked at various spatial and temporal scales by movements of biota adapted to life in water. We review the literature on movements of aquatic organisms that connect different types of freshwater habitats, focusing on linkages from streams and wetlands to downstream waters. Here, streams, wetlands, rivers, lakes, ponds, and other freshwater habitats are viewed as dynamic freshwater ecosystem mosaics (FEMs) that collectively provide the resources needed to sustain aquatic life. Based on existing evidence, it is clear that biotic linkages throughout FEMs have important consequences for biological integrity and biodiversity. All aquatic organisms move within and among FEM components, but differ in the mode, frequency, distance, and timing of their movements. These movements allow biota to recolonize habitats, avoid inbreeding, escape stressors, locate mates, and acquire resources. Cumulatively, these individual movements connect populations within and among FEMs and contribute to local and regional diversity, resilience to disturbance, and persistence of aquatic species in the face of environmental change. Thus, the biological connections established by movement of biota among streams, wetlands, and downstream waters are critical to the ecological integrity of these systems. Future research will help advance our understanding of the movements that link FEMs and their cumulative effects on downstream waters.  相似文献   
339.
Yearlong hibernation in a marsupial mammal   总被引:4,自引:3,他引:1  
Many mammals hibernate each year for about 6 months in autumn and winter and reproduce during spring and summer when they are generally not in torpor. I tested the hypothesis that the marsupial pygmy-possum (Cercartetus nanus), an opportunistic nonseasonal hibernator with a capacity for substantial fattening, would continue to hibernate well beyond winter. I also quantified how long they were able to hibernate without access to food before their body fat stores were depleted. Pygmy-possums exhibited a prolonged hibernation season lasting on average for 310 days. The longest hibernation season in one individual lasted for 367 days. For much of this time, despite periodic arousals after torpor bouts of ∼12.5 days, energy expenditure was reduced to only ∼2.5% of that predicted for active individuals. These observations represent the first report on body-fat-fuelled hibernation of up to an entire year and provide new evidence that prolonged hibernation is not restricted to placental mammals living in the cold.  相似文献   
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Measurements of low-level radioactivity often give results of the order of the detection limit. For many applications, interest is not only in estimating activity concentrations of a single radioactive isotope, but focuses on multi-isotope analyses, which often enable inference on the source of the activity detected (e.g. from activity ratios). Obviously, such conclusions become questionable if the measurement merely gives a detection limit for a specific isotope. This is particularly relevant if the presence of an isotope, which shows a low signal only (e.g. due to a short half-life or a small transition probability), is crucial for gaining the information of interest.  相似文献   
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