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171.
Reintroductions are increasingly used to reestablish species, but a paucity of long‐term postrelease monitoring has limited understanding of whether and when viable populations subsequently persist. We conducted temporal genetic analyses of reintroduced populations of swift foxes (Vulpes velox) in Canada (Alberta and Saskatchewan) and the United States (Montana). We used samples collected 4 years apart, 17 years from the initiation of the reintroduction, and 3 years after the conclusion of releases. To assess program success, we genotyped 304 hair samples, subsampled from the known range in 2000 and 2001, and 2005 and 2006, at 7 microsatellite loci. We compared diversity, effective population size, and genetic connectivity over time in each population. Diversity remained stable over time and there was evidence of increasing effective population size. We determined population structure in both periods after correcting for differences in sample sizes. The geographic distribution of these populations roughly corresponded with the original release locations, which suggests the release sites had residual effects on the population structure. However, given that both reintroduction sites had similar source populations, habitat fragmentation, due to cropland, may be associated with the population structure we found. Although our results indicate growing, stable populations, future connectivity analyses are warranted to ensure both populations are not subject to negative small‐population effects. Our results demonstrate the importance of multiple sampling years to fully capture population dynamics of reintroduced populations. Análisis Temporal de la Estructura Genética para Evaluar la Dinámica Poblacional de Zorros (Vulpes velox) Reintroducidos 相似文献
172.
Celia Arenas Carlos Leiva Luis F. Vilches Héctor Cifuentes 《Waste management (New York, N.Y.)》2013,33(11):2316-2321
The present study aims to determine and evaluate the applicability of a new product consisting of coal bottom ash mixed with Portland cement in the application of highway noise barriers. In order to effectively recycle the bottom ash, the influence of the grain particle size of bottom ash, the thickness of the panel and the combination of different layers with various particle sizes have been studied, as well as some environmental properties including leachability (EN-12457-4, NEN-7345) and radioactivity tests. Based on the obtained results, the acoustic properties of the final composite material were similar or even better than those found in porous concrete used for the same application. According to this study, the material produced presented no environmental risk. 相似文献
173.
174.
This paper presents an aerosol generation technique developed to produce dry aerosol particles of various sizes from aqueous solutions of salt. The technique was tested with sodium chloride, lithium carbonate and uranyl acetate at various aqueous concentrations which produced particles in the size range of 0.13-1.37 microm Mass Median Diameter (MMD). The generated aerosols were acceptably monodisperse with a geometric standard deviation of 1.4-2. Both MMD and Mass Median Aerodynamic Diameter (MMAD) increased significantly (p<0.001) with increased concentration of the salt in solution. The technique can also be used to generate aerosols of different chemical species. The results obtained indicate that the system is convenient for use with various aerosol-forming materials, with a stable particle size distribution being maintained for a long period of steady operation. The technique was successfully applied in wind tunnel studies to simulate the release of submicron radioactive particles and their interception by crops, grass and tree canopies. The relevance and application of the technique in other areas of environmental assessment studies is discussed. 相似文献
175.
S. Hul R.R. Tan J. Auresenia T. Fuchino D.C.Y. Foo 《Process Safety and Environmental Protection》2007,85(6):507-514
Different techniques for the synthesis of industrial water reuse/recycle networks have been developed in recent process integration research. These tools range from graphical pinch analysis approaches to mathematical programming models. The latter have the advantage of being flexible enough to incorporate various water network constraints, but in many cases these are often non-linear, thus making the identification of global optima difficult. Recent work has demonstrated the effectiveness of metaheuristic algorithms such as particle swarm optimization (PSO), for finding good solutions these problems. This work describes the use of a modified PSO for solving mixed integer non-linear programming (MINLP) models for water network synthesis. By incorporating a mutation operator for the binary variables in the model, the algorithm is able to escape sub-optimal network topologies and proceed towards better solutions than can be found with ordinary PSO. Two case studies involving water recycle/reuse are used to demonstrate the new design methodology. 相似文献
176.
The ability to detect and to develop a precise and accurate estimate of the entrainment mortality fraction is an important step in projecting power plant impacts on future fish population levels. Recent work indicates that these mortailities may be considerably less than 100% for some fish species in the early life stages. Point estimates of the entrainment mortality fraction have been developed based on probabilistic arguments, but the precision of these estimates has not been studied beyond the simple statistical test of the null hypothesis that no entrainment mortaility exists.The ability to detect entrainment mortality is explored as a function of the sample sizes (numbers of organisms collected) at the intake and discharge sampling stations of a power plant and of the proportion of organisms found alive in the intake samples (intake survival). Minimum detectable entrainment mortality, confidence interval width, and type II error (probability of accepting the null hypothesis of no entrainment mortality when there is mortality) are considered. Increasing sample size and/or decreasing sampling mortality will decrease the minimum detectable entrainment mortality, confidence interval width, and type II error for a given level of type I error.The results of this study are considered in the context of designing useful monitoring programs for determining the entrainment mortality fraction. Preliminary estimates of intake survival and the entrainment mortality fraction can be used to obtain estimates of the sample size needed for a specified level of confidence interval width or type II error. Final estimates of the intake survival and the entrainment mortality fraction can be used to determine the minimum detectable entrainment mortality and the type II error. 相似文献
177.
Nina Peuhkuri 《Behavioral ecology and sociobiology》1998,43(4-5):333-337
Individuals which deviate from the majority in groups are likely to be most vulnerable to predation. This oddity effect,
by definition, is frequency dependent, eventually fading at equal frequencies of the phenotypes in a group. It has been hypothesized
that the increased predation risk of odd individuals may play an important role in the formation of phenotypically uniform
shoals of fish. However, recent work has indicated that individuals may experience, or value, their predation hazard differently
depending on their own size in relation to that of other group members: single large fish, but not small ones, appear concerned
about their oddity in a shoal. Here I show that the apparent wariness of large fish is also expressed in a frequency-dependent
manner, closely conforming to what is predicted if the oddity effect is responsible for their behavior. Using foraging activity
of individuals as a means to evaluate their predation risk, I demonstrate with shoals comprising 12 threespine sticklebacks
(Gasterosteus aculeatus) that large fish forage least actively when in a shoal consisting of 2 large and 10 small fish. An increase in the number
of large fish to 4 among 8 small individuals clearly results in an increase in their foraging activity. However, having reached
an equal frequency with small fish in a shoal, large fish do not seem to change their foraging activity much even when their
number in a shoal increases further. In contrast, foraging activity of small sticklebacks remains fairly constant throughout
the entire range of tested shoal compositions, providing further evidence that small and large fish respond to their oddity
differently.
Received: 12 February 1998 / Accepted after revision: 7 May 1998 相似文献
178.
179.
以半导体颗粒作为光催化剂,用光和氧化剂使有机物彻底转化成二氧化碳和水。这是近十年来正在逐步完善的降解有机物的新方法。许多国家正在投入大量资金和人力进行半导体光催化反应的基础研究及应用基础研究。 相似文献
180.
《环境科学学报(英文版)》2023,35(4):483-493
When exposed to different relative humidities (RHs), the optical properties of atmospheric aerosols will change because of changes in the aerosol particle size and complex refractive index (RI), which will affect haze formation and global climate change. The potential contributions of ultrafine particles to the atmospheric optical characteristics and to haze spreading cannot be ignored because of their high particle number concentrations and strong diffusibility; measurement of the optical properties of wet ultrafine particles is thus highly important for environmental assessment. Therefore, a surface plasmon resonance microscopy with azimuthal rotation illumination (SPRM-ARI) system is designed to determine the RIs of single particle aerosols with diameters of less than 100 nm in the hygroscopic growth process. Measurements are taken using mixed single particles with different mass ratios. The RIs of mixed single aerosols at different RHs are retrieved by measuring the scattering light intensity using the SPRM-ARI system and almost all the RIs of the bicomponent particles with different mass ratios decrease with increasing water content under high RH conditions. Finally, for each of the bicomponent particles, the maximum standard deviations for the retrieved RI values are only , and , corresponding to the NaCl and NaNO3 bicomponent particles with a 3:1 mass ratio at 76.0% RH, the NaCl and glucose particles with a 1:3 mass ratio at 89.0% RH, and the NaCl and OA particles with a 1:1 mass ratio at 78.0% RH, respectively; these results indicate that the high-sensitivity SPRM-ARI system can measure the RI effectively and accurately. 相似文献