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31.
In many regions, conservation tillage has replaced conventional tilling practices to reduce soil erosion, improve water conservation, and increase soil organic matter. However, tillage can have marked effects on soil properties, specifically nutrient redistribution or stratification in the soil profile. The objective of this research was to examine soil phosphorus (P) forms and concentrations in a long-term study comparing conservation tillage (direct drilling, "No Till") and conventional tillage (moldboard plowing to 20 cm depth, "Till") established on a fine sandy loam (Orthic Humo-Ferric Podzol) in Prince Edward Island, Canada. No significant differences in total carbon (C), total nitrogen (N), total P, or total organic P concentrations were detected between the tillage systems at any depth in the 0- to 60-cm depth range analyzed. However, analysis with phosphorus-31 nuclear magnetic resonance spectroscopy showed differences in P forms in the plow layer. In particular, the concentration of orthophosphate was significantly higher under No Till than Till at 5 to 10 cm, but the reverse was true at 10 to 20 cm. Mehlich 3-extractable P was also significantly higher in No Till at 5 to 10 cm and significantly higher in Till at 20 to 30 cm. This P stratification appears to be caused by a lack of mixing of applied fertilizer in No Till because the same trends were observed for pH and Mehlich 3-extractable Ca (significantly higher in the Till treatment at 20 to 30 cm), reflecting mixing of applied lime. The P saturation ratio was significantly higher under No Till at 0 to 5 cm and exceeded the recommended limits, suggesting that P stratification under No Till had increased the potential for P loss in runoff from these sites.  相似文献   
32.
This article discusses critical comparisons between the human and nonhuman abolitionist movements in the United States. The modern nonhuman abolitionist movement is, in some ways, an extension of the anti-slavery movement of the eighteenth and nineteenth centuries and the ongoing human Civil Rights movement. As such, there is considerable overlap between the two movements, specifically in the need to simultaneously address property status and oppressive ideology. Despite intentional appropriation of terminology and numerous similarities in mobilization efforts, there has been disappointingly little academic discussion on this relationship. There are significant contentions regarding mobilization and goal attainment in the human abolitionist movement that speak to modern collective action on behalf of other animals. This article will explore the human abolitionist movement and discuss possible applications of movement organization, tactical repertoires, and goal attainment to the current nonhuman animal rights movement. Specifically, the utility of violence and legislative activism in the antislavery movement are discussed as potentially problematic approaches to abolishing nonhuman animal exploitation. Alternatively, the nonhuman animal rights focus on consumer resistance and nonviolence represent an important divergence in abolitionist mobilization.  相似文献   
33.
34.
Waste accounting has become a necessary practice for companies endeavoring to track their wastes toward realizing discrete waste minimization and pollution prevention objectives. Measurement systems and program initiatives certainly must be tested to find out what will repeatedly work for and best serve a company. Public Service Electric and Gas Company (PSE&G) has committed to revolutionizing the processes of managing materials, wastes, and their associated information. In laying out their strategic plan, company representatives specified the need for a companywide waste accounting system to enable them to monitor progress toward achieving two important short-term waste management targets by the close of 1995. Together with the Electric Power Research Institute, PSE&G is implementing a four-year program to install such a system. The results of the first year-and-a-half's work are reported in this article. The purpose of this article is to discuss the results of implementing a waste accounting system on a utility companywide basis. We will address the experience of bringing such a system on-line at PSE&G. The Electric Power Research Institute (EPRI) previously developed a framework and approach for measuring the performance of utility pollution prevention programs called waste accounting, including the development of a software program called Accounting Software Application for Pollution Prevention or ASAPP.1 These programs were devised to assimilate detailed information from the facility up through the corporate levels.  相似文献   
35.
Female mammals can increase their lifetime fitness through modification of investment potential and by providing better rearing environments with improved breeding experience. We examined the relationships between reproductive fitness and the behavioural decisions that female southern elephant seals (Mirounga leonina) made during the breeding season. We examined whether mother age and breeding experience influenced reproductive success (measured as 1st-year survival probability), and whether there was a change in the choice of harem size with increasing age. Pups produced by young mothers had lower 1st-year survival probability than pups produced by older mothers. A significant increase in mean female mass with age required an analysis of both these effects on offspring survival. There was a significant positive effect of both female age and mass, and the interaction between the two, on 1st-year pup survival. The proportion of young mothers (<5 years old) decreased and the proportion of older mothers (>6 years old) increased with increasing harem size (harems surveyed from 1997 to 2001). Females chose larger harems in which to breed as they aged. Females demonstrated fidelity to breeding areas among successive breeding seasons, with older females displaying greater breeding-site fidelity than younger females. The mean number of previous breeding attempts per female within a harem (breeding experience) increased significantly with increasing harem size. Breeding females returned to breed later in the breeding season as they aged—we hypothesize that young, subordinate females gain a priority advantage by returning earlier. These results lend support to the hypothesis that there are fitness advantages, in terms of offspring survival, that are conferred to females that breed in successively larger harems with age. Potential mechanisms that select for females to improve their breeding conditions include improved mate selection and the avoidance of conspecific harassment in harems.Communicated by F. Trillmich  相似文献   
36.
In an effort to explore the role of new media technologies in environmental protest rhetoric, this paper examines Greenpeace's Let's Go! Arctic campaign, which opposed Shell's Arctic oil-drilling plans. The campaign produced a body of Internet memes designed to look like Shell's own corporate advertising. Moreover, the viral campaign used various rhetorical techniques that challenged Shell's goals and identity. Greenpeace-generated and user-generated memes cleverly use irony, corporate voice and humor to delegitimize Shell's Arctic efforts. The memes offered messages that mocked corporate practices and corporate messaging while also providing direct protest messages and accessible humor that invited identification against Shell. Thus, the memes collectively encouraged identification with Greenpeace's antidrilling, pro-environment discourse.  相似文献   
37.
Lack of diversity in the ranks as well as a failure to resonate with disadvantaged groups and other anti-oppression movements has been cited as one important barrier to the American Nonhuman Animal rights movement’s success (Kymlicka and Donaldson in Animal rights, multiculturalism and the Left. The Mellon Sawyer Seminar at the Graduate Center, CUNY. City University of New York, New York, 2013). It is possible that social movements are actively inhibiting diversity in the ranks and audience by producing literature that reflects a narrow activist identity. This article creates a platform from which these larger issues can be explored by investigating the actual demographic representations present in a small sample of popular media sources produced by the movement for other animals. A content analysis of 131 magazine covers produced by two highly visible movement actors, PETA and VegNews, was conducted to demonstrate that activist representations in at least some dominant American Nonhuman Animal rights media are mostly white, female, and thin.  相似文献   
38.
Recent advances in telemetry technology have created a wealth of tracking data available for many animal species moving over spatial scales from tens of meters to tens of thousands of kilometers. Increasingly, such data sets are being used for quantitative movement analyses aimed at extracting fundamental biological signals such as optimal searching behavior and scale-dependent foraging decisions. We show here that the location error inherent in various tracking technologies reduces the ability to detect patterns of behavior within movements. Our analyses endeavored to set out a series of initial ground rules for ecologists to help ensure that sampling noise is not misinterpreted as a real biological signal. We simulated animal movement tracks using specialized random walks known as Lévy flights at three spatial scales of investigation: 100-km, 10-km, and 1-km maximum daily step lengths. The locations generated in the simulations were then blurred using known error distributions associated with commonly applied tracking methods: the Global Positioning System (GPS), Argos polar-orbiting satellites, and light-level geolocation. Deviations from the idealized Lévy flight pattern were assessed for each track after incrementing levels of location error were applied at each spatial scale, with additional assessments of the effect of error on scale-dependent movement patterns measured using fractal mean dimension and first-passage time (FPT) analyses. The accuracy of parameter estimation (Lévy mu, fractal mean D, and variance in FPT) declined precipitously at threshold errors relative to each spatial scale. At 100-km maximum daily step lengths, error standard deviations of > or = 10 km seriously eroded the biological patterns evident in the simulated tracks, with analogous thresholds at the 10-km and 1-km scales (error SD > or = 1.3 km and 0.07 km, respectively). Temporal subsampling of the simulated tracks maintained some elements of the biological signals depending on error level and spatial scale. Failure to account for large errors relative to the scale of movement can produce substantial biases in the interpretation of movement patterns. This study provides researchers with a framework for understanding the limitations of their data and identifies how temporal subsampling can help to reduce the influence of spatial error on their conclusions.  相似文献   
39.
A number of models have been proposed to provide adaptive explanations of sex-ratio variation in mammals. Two models have been applied commonly to primates and ungulates with varying success—the Trivers-Willard (TW) hypothesis, and the local resource competition (LRC) hypothesis. For polygynous, sexually dimorphic mammals, where males are larger and disperse more readily, these models predict opposite outcomes of sex-ratio adjustment within the same environmental context (high-resource years: TW—more sons; LRC—more daughters). However, many of the predictions of these two models can vary depending on factors influencing resource availability, such as environmental stochasticity, resource predictability, and population density. The New Zealand fur seal (Arctocephalus forsteri) is a polygynous mammal showing marked sexual dimorphism (larger males), with higher variation in male reproductive success expected. We provide clear evidence of male-biased sex ratios from a large sample of A. forsteri pups captured around South Island, New Zealand during 1996/1998, even after accounting for a sex bias in capture probability. The extent of the bias depended upon year and, in 1998, strong climatic perturbations (El Niño/Southern Oscillation, ENSO) probably reduced food availability. Significant male-biased sex ratios were found in all years; however, there was a significant decline in the male bias in 1998. There was no relationship between sex ratio and population density. We suggest that the sex-ratio bias resulted from the production of relatively more male pups. Under the density-independent scenario, the strong male bias in A. forsteri sex ratios is support for the TW model within an environment of high resource predictability. We suggest that some plasticity in the determination of pup sex among years is a mechanism by which A. forsteri females in New Zealand, and perhaps other otariid seals, can maximise fitness benefits when living in regions of high, yet apparently predictable, environmental variability. We also suggest that much of the inconsistency in the reported sex ratios for otariid seals results from the complex interaction of population density and environmental stochasticity influencing relative food availability over time.  相似文献   
40.
A historical explosives testing area harbored contamination as unevenly distributed solid particles within a contaminant-stained soil matrix. Particles larger than 3 mm diameter accounted for 96.4% of the explosives contamination. Independent sampling and analysis methods showed significant differences in contaminant estimations due to particulate explosives. We present a solvent-based sample averaging method designed to solve spatial heterogeneity problems resulting from the presence of contaminant particles.  相似文献   
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