2,175 research outputs found
Brownian motion on the Sierpinski carpet
We prove that, up to scalar multiples, there exists only one local regular
Dirichlet form on a generalized Sierpinski carpet that is invariant with
respect to the local symmetries of the carpet. Consequently for each such
fractal the law of Brownian motion is uniquely determined and the Laplacian is
well defined
Workers’ Compensation and Occupational Disease
Workers’ Compensatio
The Operational-Bayesian Approach In Reliability Theory
nuloWe emphasize the derivation of likelihood models starting from a well specified problem of interest and finite populations. "Parameters" are given operational meaning. In particular, parameters are specified in terms of different forms of energy. Examples relevant to reliability theory are used to illustrate ideas. Examples in engineering probability are given
Indenture, Marshall County, MS, 13 November 1855
https://egrove.olemiss.edu/aldrichcorr_c/1105/thumbnail.jp
The value of trophic interactions for ecosystem function:Dung beetle communities influence seed burial and seedling recruitment in tropical forests
Anthropogenic activities are causing species extinctions, raising concerns about the consequences of changing biological communities for ecosystem functioning. To address this, we investigated how dung beetle communities influence seed burial and seedling recruitment in the Brazilian Amazon. First, we conducted a burial and retrieval experiment using seed mimics. We found that dung beetle biomass had a stronger positive effect on the burial of large than small beads, suggesting that anthropogenic reductions in large-bodied beetles will have the greatest effect on the secondary dispersal of large-seeded plant species. Second, we established mesocosm experiments in which dung beetle communities buried Myrciaria dubia seeds to examine plant emergence and survival. Contrary to expectations, we found that beetle diversity and biomass negatively influenced seedling emergence, but positively affected the survival of seedlings that emerged. Finally, we conducted germination trials to establish the optimum burial depth of experimental seeds, revealing a negative relationship between burial depth and seedling emergence success. Our results provide novel evidence that seed burial by dung beetles may be detrimental for the emergence of some seed species. However, we also detected positive impacts of beetle activity on seedling recruitment, which are probably because of their influence on soil properties. Overall, this study provides new evidence that anthropogenic impacts on dung beetle communities could influence the structure of tropical forests; in particular, their capacity to regenerate and continue to provide valuable functions and services. </jats:p
An economic analysis of soil conservation policy for selected commercial farms in KwaZulu-Natal.
Thesis (M.Sc.Agric.)-University of Natal, Pietermaritzburg, 1995.Inherent in the erosion process is a high level of uncertainty. This is associated with the
inability to accurately quantify and predict the consequences of prolonged erosion for
agricultural production, or estimate the time period over which induced innovations will be able to compensate for it. Therefore, there are incentives to formulate strategies that will
achieve tangible reductions in erosion.
Data were collected through a postal survey conducted in October 1993, from the following
five commercial farming regions: Dalton/Wartburg, Camperdown/Eston, Dundee, Estcourt,
and Winterton. Soil conservation incentives are expected to differ according to enterprise
types and site-specific circumstances, and stratifying according to these regions incorporates
a diverse spectrum of agricultural systems. There were 480 potential survey respondents,
and 159 (35 percent) usable questionnaires were returned. The response rate is relatively
good for a postal survey, although results may be slightly biased in favour of farmers that
are concerned or interested in soil conservation.
Adoption of soil conservation measures is modelled as a multi-stage decision process,
representing the following phases: awareness of the erosion problem, the perception that
erosion is worth trying to resolve, farmers' technical and financial abilities to implement soil
conservation measures required for their farms, and finally the actual adoption of
conservation practices. A logistic regression analysis shows visible erosion impacts,
knowledge of erosion's adverse implications for agricultural productivity, farmers'
willingness to invest their own capital in conservation activities, predominantly crop farms,
and sufficient financial resources, have significant positive impacts on adoption. The mean
predicted probability score for the Technical Ability model is 0.54, illustrating farmers' lack
of technical soil conservation skills to implement appropriate conservation measures is a
major constraining factor within the adoption process.
Variables influencing conservation effort, reflecting the extensiveness and effectiveness of
soil conservation measures, are expected to differ from those affecting adoption, and effort
is modelled separately using linear regression. Results support prior expectations indicating
conservation effort depends mainly on the following financial characteristics: farmers'
willingness to invest their own capital in conservation activities, debt fmancing, and on-farm
financial and managerial benefits from implementing soil conservation activities.
Farmers' perceptions regarding the monitoring and enforcement of soil conservation
legislation are also analyzed using frequency tables. Although 65 percent of respondents
believe that violations of Act 43/1983 will be discovered, only 20 percent perceive that
transgressions will be both detected and subsequently prosecuted. This suggests the
transactions costs related to enforcing prosecutions are high, and the possibility of being
prosecuted is unlikely to encourage farmers to implement soil conservation activities.
Agents (eg. Soil Conservation Committees and extension officers), and media (eg. extension
service reports) play an invaluable role in promoting soil conservation. High transactions
costs associated with enforcing legislation indicate it may be appropriate for the government
to play an active part in research, and in providing information about erosion and soil
conservation, to facilitate a better functioning land market. This is distinct from having a
clear advantage over market forces in the use of this information. Cross-compliance
programs, should perhaps be considered as short to medium-term strategies, to encourage
farmers to implement soil conservation activities
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