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351.
In mammals, fathers are facultative caretakers, and male care is expected to evolve only if it is directed towards related young. Yet, in several promiscuous primate societies, males seem to care for infants despite a presumably low paternity confidence. In cercopithecines, cohesive associations (‘friendships’) between a lactating female and an adult male are frequent and provide the female and her infant with protection against various sources of aggression, including infanticide. However, the benefits gained by males through such relationships remain unclear, in part, because the relatedness between males and their protected infants has rarely been examined. Moreover, little is known about the nature of the cues underlying kin discrimination by males in societies where females mate polyandrously. In this study, we combine behavioural and genetic data from wild chacma baboons (Papio ursinus) in Namibia to investigate (1) whether males are related to their friend’s infant and (2) whether similarity between the major histocompatibility complex (MHC) genotype of males and infants (potentially perceived through odour phenotype) favours the establishment of friendships. We first show that males share close genetic ties with their friend’s infants, most often by having sired the infant. Secondly, we find that male–infant MHC (Class II–DRB) similarity, in contrast to paternity, does not predict male–infant associations. Overall, our results clarify the nature of the evolutionary benefits gained by males in these heterosexual associations, which can be considered as true paternal care. However, the proximate mechanisms underlying paternity recognition remain to be identified.  相似文献   
352.
The aim of this work is to use GIS integration data to characterize sedimentary processes in a SubTropical lagoon environment. The study area was the Cananéia Inlet estuary in the southeastern section of the Cananéia Lagoon Estuarine System (CLES), state of S?o Paulo, Brazil (25°03′S/47°53′W). The area is formed by the confluence of two estuarine channels forming a bay-shaped water body locally called “Trapandé Bay”. The region is surrounded by one of the most preserved tracts of Atlantic Rain Forest in Southwestern Brazil and presents well-developed mangroves and marshes. In this study a methodology was developed using integrated a GIS database based on bottom sediment parameters, geomorphological data, remote sensing images, Hidrodynamical Modeling data and geophysical parameters. The sediment grain size parameters and the bottom morphology of the lagoon were also used to develop models of net sediment transport pathways. It was possible to observe that the sediment transport vectors based on the grain size model had a good correlation with the transport model based on the bottom topography features and Hydrodynamic model, especially in areas with stronger energetic conditions, with a minor contribution of finer sediments. This relation is somewhat less evident near shallower banks and depositional features. In these regions the organic matter contents in the sediments was a good complementary tool for inferring the hydrodynamic and depositional conditions (i.e. primary productivity, sedimentation rates, sources, oxi-reduction rates).  相似文献   
353.
Due to the expected increase in the percentage of diesel vehicles in the United States, the Environmental Protection Agency must evaluate the health effects associated with exposure to diesel emissions. Respirable particles from a variety of combustion sources have the potential of being carcinogenic and mutagenic. The objective of these studies was to determine the relative biological activity of the organic material adsorbed on these particles in in vitro mutagenesis bioassays. The organic extracts from the following series of emission sources were bioassayed in the Salmonella assay for mutagenic activity: (1) a light-duty Oldsmobile diesel 350 engine; (2) a heavy-duty Caterpillar diesel engine; (3) a light-duty Nissan engine; (4) a Volkswagen Rabbit diesel engine; (5) cigarette smoke; (6) roofing tar; (7) coke oven; and (8) a gasoline catalyst Mustang. This paper provides a comparison of these sources within the Salmonella bioassay and also demonstrates how bacterial systems can be used as a quality assurance measure in in vivo testing.  相似文献   
354.
Summary This paper reviews development in environmental education in the three preceding decades of the 1950s, 1960s and 1970s. It then sets out the major sets of obstacles which need to be examined. Finally it deals with the 1980s and why this should be the decade of action. Referring to the IUCN World Conservation Strategy it is concerned with speeding up of the awareness of environmental problems in order to beat our race against time.Directeur, Programme Interdisciplinaire du territoire et développement régional, Université Laval. Member of Commission on Education, IUCN.  相似文献   
355.
Automated and continuous redox potential measurements in soil   总被引:2,自引:0,他引:2  
Redox potential (Eh) describes the electrical state of a matrix. In soils, Eh is an important parameter controlling the persistence of many organic and inorganic compounds. A popular, but also criticized, manual measuring method makes use of a small tip of Pt placed on a copper wire that is placed in the soil; a reference electrode is placed in the same soil at a fixed distance. Fluctuations in redox potential values measured in the soil can be very large and depth-dependent. This will be overlooked when making single-point measurements. We developed the datalogger Hypnos 2.0 for continuous redox potential and temperature measurements at various depths in the soil and without disturbance of the site. Hypnos is field-deployable, relatively cheap, and runs on batteries. The datalogger can use a "sleep mode" between sampling events. In sleep mode, there is no constant voltage on the Pt wire or the reference electrode, but there is only a short pulse during sampling. We did not measure an effect of this short pulse on the measured redox potential. In sandy soils in mesocosms and in a salt marsh soil we measured changes in the Eh as large as from -400 to +100 mV within 4 d, and daily cycles of 200 mV. Both absolute redox potential values and their diurnal variations were depth-dependent. Because single redox measurements are insufficient in describing redox conditions in some soil systems, Hypnos can be a powerful tool when studying the effects of fluctuating redox conditions on metal availability and pollutant degradation.  相似文献   
356.
This paper describes a systematic method for comparing options for the long-term management of surplus elemental mercury in the US, using the analytic hierarchy process as embodied in commercially available Expert Choice software. A limited scope multi-criteria decision analysis was performed. Two (2) general types of treatment technologies were evaluated (stabilization/amalgamation and selenide), combined with four (4) disposal options: (a) hazardous waste landfill; (b) hazardous waste monofill; (c) engineered below-ground structure; and (d) mined cavity. In addition, three storage options for elemental mercury were considered: (a) aboveground structure; (b) hardened structure; and (c) mined cavity. Alternatives were evaluated against criteria that included costs, environmental performance, compliance with current regulations, implementation considerations, technology maturity, potential risks to the public and workers, and public perception. Considering non-cost criteria only, the three storage options rank most favorably. If both cost and other criteria are considered, then landfill options are preferred, because they are the least expensive ones. Storage options ranked unfavorably on cost because: (a) even relatively small per annum costs will add up over time; and (b) storage is a temporary solution and, sooner or later, a treatment and disposal technology will be adopted, which adds to the cost. However, the analysis supports continued storage for a short period (up to a few decades) followed by permanent retirement when treatment technologies have matured. Suggestions for future work include: (a) involving additional stakeholders in the process, (b) evaluating alternatives for mercury-containing wastes rather than for elemental mercury only, (c) revisiting the analysis periodically to determine if changes are required, (d) conducting uncertainty analyses utilizing Monte Carlo-based techniques.  相似文献   
357.
The objective of this paper is to report on the results of a study of 238Pu, 239 + 240Pu and 241Am inventories onto Blelham Tarn in Cumbria (UK). The atmospheric fallout inventory was obtained by analysing soil cores and the results are in good agreement with the literature: 101 Bq m(-2) for 239 + 240Pu; 4.5 Bq m(-2) for 238Pu and 37 Bq m(-2) for 241Am. The sediment core inventory for the whole lake is compared to the atmospheric fallout inventory. The sediment activity is 60-80% higher than the estimated fallout activity, showing a catchment area contribution and in particular the stream input.  相似文献   
358.
Devils Lake, located in a closed basin in northeastern North Dakota has over a century-long history of highly fluctuating water levels. The lake has risen nearly 25 feet (7.7 m) since 1993, more than doubling its surface area. Rising water levels have affected rural lands, transportation routes, and communities near the lake. In response to rising lake levels, Federal, state and local agencies have adopted a three-part approach to flood damage reduction, consisting of (1) upper basin water management to reduce the amount of water reaching the lake, (2) protection for structures and infrastructure if the lake continues to rise, and (3) developing an emergency outlet to release some lake water. The purpose of this study was to provide information about the net regional economic effects of a proposed emergency outlet for Devils Lake. An input-output model was used to estimate the regional economic effects of the outlet, under two scenarios: (1) the most likely future situation (MLS) and (2) a best case situation (BCS) (i.e., where the benefits from the outlet would be greatest), albeit an unlikely one. Regional economic effects of the outlet include effects on transportation (road and railroad construction), agriculture (land kept in production, returned to production sooner, or kept in production longer), residential relocations, and outlet construction expenditures. Effects are measured as changes in gross business volume (gross receipts) for various sectors, secondary employment, and local tax collections. The net regional economic effects of the proposed outlet would be relatively small, and consideration of these economic impacts would not strengthen the case for an outlet.  相似文献   
359.
There is continuing concern over potential impacts of widespread application of nutrients and pesticides on ground- and surface-water quality. Transport and fate of nitrate and pesticides were investigated in a shallow aquifer and adjacent stream, Cow Castle Creek, in Orangeburg County, South Carolina. Pesticide and pesticide degradate concentrations were detected in ground water with greatest frequency and largest concentrations directly beneath and downgradient from the corn (Zea mays L.) field where they were applied. In almost all samples in which they were detected, concentrations of pesticide degradates greatly exceeded those of parent compounds, and were still present in ground waters that were recharged during the previous 18 yr. The absence of both parent and degradate compounds in samples collected from deeper in the aquifer suggests that this persistence is limited or that the ground water had recharged before use of the pesticide. Concentrations of NO(-)(3) in ground water decreased with increasing depth and age, but denitrification was not a dominant controlling factor. Hydrologic and chemical data indicated that ground water discharges to the creek and chemical exchange takes place within the upper 0.7 m of the streambed. Ground water had its greatest influence on surface-water chemistry during low-flow periods, causing a decrease in concentrations of Cl(-), NO(-)(3), pesticides, and pesticide degradates. Conversely, shallow subsurface drainage dominates stream chemistry during high-flow periods, increasing stream concentrations of Cl(-), NO(-)(3), pesticides, and pesticide degradates. These results point out the importance of understanding the hydrogeologic setting when investigating transport and fate of contaminants in ground water and surface water.  相似文献   
360.
Security buffers of Department of Defense (DoD) and Department of Energy (DOE) reservations provide long-term habitat protection for many rare and endangered species. The importance of these government-owned reservations as nationally valuable resources has been relatively unrecognized. During the last 50 years, the DOE Oak Ridge Reservation (ORR) has been a relatively protected island in a region of rapidly expanding urbanization and land clearing. Consisting of the Oak Ridge National Environmental Research Park and associated lands surrounding DOE facilities at Oak Ridge Tennessee, the unique nature of the ORR in the surrounding landscape is clearly visible from the air and has been documented using remote sensing data. Although forests dominate much of other regions of eastern Tennessee, this 15,000-ha tract of mostly natural forest habitat is unique in the southern Ridge and Valley physiographic province, which is otherwise widely developed for pasture, marginal cropland, woodlot, and urban uses. Twenty state-listed and federal-candidate plant species are known to be present on the ORR. This richness of species, which are provided protection by state and federal laws, exceeds that of the Great Smoky Mountains National Park on a species area basis and is an index of the value of the ORR both regionally and nationally in conserving biodiversity. With the end of the Cold War, changing DoD and DOE missions combined with increasing development pressure contribute to uncertainty in the future management of security reservations.  相似文献   
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