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1.
Oliveira Flávio G. Tapisso Joaquim T. von Merten Sophie Rychlik Leszek Fonseca Paulo J. Mathias Maria da Luz 《Urban Ecosystems》2021,24(5):851-862
Urban Ecosystems - The development of urban areas imposes challenges that wildlife must adapt to in order to persist in these new habitats. One of the greatest changes brought by urbanization has... 相似文献
2.
Fire and restoration of the largest urban forest of the world in Rio de Janeiro City,Brazil 总被引:1,自引:1,他引:0
National Park of Tijuca in Rio de Janeiro (Brazil) is about 3,300 ha and considered the largest urban forest in the world. Its floristic composition is typical of Atlantic Rain Forest. The reserve is being altered because of fire occurrences and urban expansion. This study identified locations and causes of forest fires, and makes management recommendations to restore damaged areas. From 1991 to 2000, forest firefighters recorded an average of 75-fire occurrences/year. Identified causes included hot air balloons (24%), intentional (24%), rubbish burning (21%) and religious practices (17%). Primary fuels included invasive grasses and ferns. Although hot air balloons destroyed larger areas of forest in each occurrence, a greater number of fires started in the invasive vegetation along roads that bisect the forest. In response to recurrent forests, invasive vegetation has spread gradually into the forest increasing forest degradation. To decrease fire damage, sites with high fire frequencies and density of invasive vegetation were planted with less flammable species. Results indicate that fire frequency decreased and density of invasive vegetation declined. This approach appears to prevent fire incidence, reduce the need for fire fighting, and preserve existing biodiversity. 相似文献
3.
Angelo Zanella 《Statistical Methods and Applications》1992,1(1):143-160
Summary For technological applications it can be useful to identify some simple physical mechanisms, which, on the basis of the available
knowledge of the production process, may suggest the most appropriate approach to statistical control of the random quantities
of interest. For this purpose the notion of rupture point is introduced firstly. A rupture point is characterized bym randomly arising out of control states, assumed to be mutually exclusive and stochastically independent. Shewhart's control
charts seem to represent the natural statistical tool for controlling a rupture point; however it is shown that they are fully
justified only when the hazard rates attached to the causes of failure are constant. Otherwise, typically in the presence
of time increasing hazard rates, Shewhart's control charts should be completed by a preventive intervention rule (preventive
maintenance). In the second place, the notion of dynamic instability point is introduced, which is specifically characterized
by assuming that the random quantity of interest is ruled by a stochastic differential equation with constant coefficients.
By discretization, developed according to a possibly new approach, it is shown that the former model reduces to an equation
error model, which is among the simplest used in adaptive control, and thus particularly easy to deal with in regard to parameter
estimation and the definition of the optimum control rule. 相似文献
4.
We study, from the standpoint of coherence, comparative probabilities on an arbitrary familyE of conditional events. Given a binary relation ·, coherence conditions on · are related to de Finetti's coherent betting system: we consider their connections to the usual properties of comparative probability and to the possibility of numerical representations of ·. In this context, the numerical reference frame is that of de Finetti's coherent subjective conditional probability, which is not introduced (as in Kolmogoroff's approach) through a ratio between probability measures.Another relevant feature of our approach is that the family & need not have any particular algebraic structure, so that the ordering can be initially given for a few conditional events of interest and then possibly extended by a step-by-step procedure, preserving coherence. 相似文献
5.
A Stochastic Model to Assess the Effect of Meat Inspection Practices on the Contamination of the Pig Carcasses
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Eduardo de Freitas Costa Luis Gustavo Corbellini Ana Paula Serafini Poeta da Silva Maarten Nauta 《Risk analysis》2017,37(10):1849-1864
The objective of meat inspection is to promote animal and public health by preventing, detecting, and controlling hazards originating from animals. With the improvements of sanitary level in pig herds, the hazards profile has shifted and the inspection procedures no longer target major foodborne pathogens (i.e., not risk based). Additionally, carcass manipulations performed when searching for macroscopic lesions can lead to cross‐contamination. We therefore developed a stochastic model to quantitatively describe cross‐contamination when consecutive carcasses are submitted to classic inspection procedures. The microbial hazard used to illustrate the model was Salmonella, the data set was obtained from Brazilian slaughterhouses, and some simplifying assumptions were made. The model predicted that due to cross‐contamination during inspection, the prevalence of contaminated carcass surfaces increased from 1.2% to 95.7%, whereas the mean contamination on contaminated surfaces decreased from 1 logCFU/cm² to ?0.87 logCFU/cm², and the standard deviations decreased from 0.65 to 0.19. These results are explained by the fact that, due to carcass manipulations with hands, knives, and hooks, including the cutting of contaminated lymph nodes, Salmonella is transferred to previously uncontaminated carcasses, but in small quantities. These small quantities can easily go undetected during sampling. Sensitivity analyses gave insight into the model performance and showed that the touching and cutting of lymph nodes during inspection can be an important source of carcass contamination. The model can serve as a tool to support discussions on the modernization of pig carcass inspection. 相似文献
6.
7.
Patrícia M. Pascoal Pedro J. Rosa Elizabet Pereira da Silva Pedro J. Nobre 《心理学和人类性特征杂志》2018,30(1):60-71
Dysfunctional sexual beliefs are vulnerability factors for sexual dysfunction. This cross-sectional study aimed to test the mediating role of cognitive distraction on the relationship between dysfunctional sexual beliefs about sexual functioning shared by men and women and sexual function. The authors used a sample of 421 cisgender heterosexual participants involved in a monogamous relationship. The hypothesized mediation model was tested using a bootstrapped cross product of coefficients approach. Results showed a significant negative, indirect effect between dysfunctional sexual beliefs and women's sexual function through cognitive distraction. The discussion of this study highlights the importance of cognitive factors in sexual functioning. 相似文献
8.
Word clouds constitute one of the most popular statistical tools for the visual analysis of text documents because they provide users with a quick and intuitive understanding of the content. Despite their popularity for visualizing single documents, word clouds are not appropriate to compare different text documents. Independently generating word clouds for each document leads to configurations where the same word is typically located in widely different positions. This makes it very difficult to compare two or more word clouds. This paper introduces COWORDS, a new stochastic algorithm to create multiple word clouds, including one for each document. The shared words in multiple documents are placed in the same position in all clouds. Similar documents produce similar and compact clouds, making it easier to simultaneously compare and interpret several word clouds. The algorithm is based on a probability distribution in which the most probable configurations are those with a desirable visual aspect, such as a low value for the total distance between the words in all clouds. The algorithm output is a set of word clouds that are randomly selected from this probability distribution. The selection procedure uses a Markov chain Monte Carlo simulation method. We present several examples that illustrate the performance and visual results that can be obtained by our algorithm. 相似文献
9.
Marcelo Marchesini da Costa 《Voluntas: International Journal of Voluntary and Nonprofit Organizations》2016,27(3):1064-1090
What are the local characteristics influencing where new nonprofits will be established? How important are community needs, available resources, or the existence of similar organizations for nonprofits’ location? This paper analyzes how the characteristics of 5562 Brazilian municipalities in the year 2000 help explain the location of nonprofits formed between 2001 and 2010. Based on geographically weighted regressions, results indicate that neither access to resources nor poor socioeconomic indicators are powerful influences on nonprofit location in Brazilian municipalities. The main predictor of nonprofit entry is a high pre-existing density of nonprofits in that area. These findings, however, vary across regions and nonprofit fields of activity. By mapping the effect of key explanatory variables, this paper helps understand nonprofit location. The methodology and findings on nonprofit location presented here are novel and may contribute to research in other countries. 相似文献
10.