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61.
Data mining techniques are a powerful method for extracting information from large databases. Among these techniques, clustering and projection of data from high-dimensional spaces hold a main role, since they allow to discover hidden structures in the data set. Following this approach, this paper presents a data analysis method designed to help the management and investigation of occupational accident databases. The purpose is to discover the most common sequences of events leading to accidents for devising preventive actions. To this aim, we developed a two-level approach based on the joint use of the Kohonen’s Self-Organizing Map and the k-means clustering algorithm. This approach allows not only to group the accidents in different classes but also to visualize them in a way understandable for the analyst. The method has been applied with satisfactory results to a large database of occupational accidents occurred in the Italian wood processing industry. A comparison with the Hierarchical Clustering method confirmed the effectiveness of the proposed approach. 相似文献
62.
63.
Adrados A de Marco I Caballero BM López A Laresgoiti MF Torres A 《Waste management (New York, N.Y.)》2012,32(5):826-832
Pyrolysis may be an alternative for the reclamation of rejected streams of waste from sorting plants where packing and packaging plastic waste is separated and classified. These rejected streams consist of many different materials (e.g., polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), aluminum, tetra-brik, and film) for which an attempt at complete separation is not technically possible or economically viable, and they are typically sent to landfills or incinerators. For this study, a simulated plastic mixture and a real waste sample from a sorting plant were pyrolyzed using a non-stirred semi-batch reactor. Red mud, a byproduct of the aluminum industry, was used as a catalyst. Despite the fact that the samples had a similar volume of material, there were noteworthy differences in the pyrolysis yields. The real waste sample resulted, after pyrolysis, in higher gas and solid yields and consequently produced less liquid. There were also significant differences noted in the compositions of the compared pyrolysis products. 相似文献
64.
Fabrice Dentressangle Lourdes Boeck Roxana Torres 《Behavioral ecology and sociobiology》2008,62(12):1899-1908
Females are expected to vary investment in offspring according to variables that may influence the offspring fitness in a way that optimises her inclusive fitness for a particular context. Thus, when sexual ornaments signal the quality of the male, females might invest in reproduction as a function of the attractiveness of their mate. We tested whether breeding conditions and male feet colour influence reproductive decisions of blue-footed booby females. In the blue-footed booby, male feet colour is a dynamic condition-dependent sexually selected trait that is related to paternal effort. During two consecutive years, an El Niño year (poor breeding conditions) and a year with good breeding conditions, we experimentally reduced male attractiveness by modifying their feet colour after the first egg was laid and recorded female investment in the second egg. We found that, relative to the first egg in the clutch, females laid heavier second eggs during the poor year than during the good year. Females paired with males with duller feet colour reduced second-egg mass and volume and delayed the laying of the second egg, independently of the year. Absolute yolk androstenedione (A4) concentration (but not testosterone, T) in second eggs was higher during a poor year than during a good year. Only during a year with poor breeding conditions, females paired with experimental males decreased the relative A4 concentration (but not T) in the second egg compared to control females. Thus, blue-footed booby females probably favour brood reduction by decreasing egg quality and increasing size asymmetry between chicks when the breeding and the mate conditions are poor. 相似文献
65.
Emilio Chuvieco Sergio Opazo Walter Sione Hector Del Valle Jesús Anaya Carlos Di Bella Isabel Cruz Lilia Manzo Gerardo López Nicolas Mari Federico González-Alonso Fabiano Morelli Alberto Setzer Ivan Csiszar Jon Ander Kanpandegi Aitor Bastarrika Renata Libonati 《Ecological applications》2008,18(1):64-79
This paper presents results of the AQL2004 project, which has been develope within the GOFC-GOLD Latin American network of remote sensing and forest fires (RedLatif). The project intended to obtain monthly burned-land maps of the entire region, from Mexico to Patagonia, using MODIS (moderate-resolution imaging spectroradiometer) reflectance data. The project has been organized in three different phases: acquisition and preprocessing of satellite data; discrimination of burned pixels; and validation of results. In the first phase, input data consisting of 32-day composites of MODIS 500-m reflectance data generated by the Global Land Cover Facility (GLCF) of the University of Maryland (College Park, Maryland, U.S.A.) were collected and processed. The discrimination of burned areas was addressed in two steps: searching for "burned core" pixels using postfire spectral indices and multitemporal change detection and mapping of burned scars using contextual techniques. The validation phase was based on visual analysis of Landsat and CBERS (China-Brazil Earth Resources Satellite) images. Validation of the burned-land category showed an agreement ranging from 30% to 60%, depending on the ecosystem and vegetation species present. The total burned area for the entire year was estimated to be 153 215 km2. The most affected countries in relation to their territory were Cuba, Colombia, Bolivia, and Venezuela. Burned areas were found in most land covers; herbaceous vegetation (savannas and grasslands) presented the highest proportions of burned area, while perennial forest had the lowest proportions. The importance of croplands in the total burned area should be taken with reserve, since this cover presented the highest commission errors. The importance of generating systematic products of burned land areas for different ecological processes is emphasized. 相似文献
66.
Marmett Bruna Carvalho Roseana Böek Dorneles Gilson Pires da Silva Igor Martins Romão Pedro Roosevelt Torres Nunes Ramiro Barcos Rhoden Cláudia Ramos 《Environmental science and pollution research international》2020,27(31):39019-39028
Environmental Science and Pollution Research - Obesity and physical inactivity threaten human health, and both could be solved with exercise. However, a higher amount of pollutants is inhaled... 相似文献
67.
In order to develop small islands, not only must a vital agricultural system be maintained, but the range of opportunities
for tourism must be increased with respect to both the seaside and the environmental features of the rural landscape. As an
alternative to the traditional and economically declining ones, many innovative production processes can be identified, but
their success depends on their interaction with the physical, biological, economic and social environment. In order to identify
the main nodes and the most critical interactions, so as to increase the probability of success of a new productive process,
a methodological approach based on the science of complexity is proposed for the cultivation of capers (Capparis spinosa L.) on the island of Pantelleria. The methodology encompasses the identification of actors and factors involved. the quantitative
evaluation of their interactions with the different stages of the productive process, and a quasiquantitative evaluation of
the probability that the particular action will be performed successfully.
The study of “traditional,” “modernized,” and “modernized-sustainable” processes, shows that the modernized-sustainable process
offers mutually reinforcing opportunities in terms of an integrated development of high-quality agricultural products and
the enhancement of environmental features, in conjunction with high-efficiency production techniques, in conjunction with
high-efficiency production techniques, in a way that suits the development of Pantelleria. There is a high probability of
failure, however, as a result of the large number of critical factors. Nevertheless, the present study indicates which activities
will enhance the probability of successful innovation in the production process. 相似文献
68.
Borghini F Grimalt JO Sanchez-Hernandez JC Barra R García CJ Focardi S 《Environmental pollution (Barking, Essex : 1987)》2005,136(2):253-266
Semi-volatile organochlorine compounds (OC) were analyzed in remote Andean soils and lake sediments. The sampling sites covered a wide latitudinal gradient from 18 degrees S to 46 degrees S along Chile and an altitudinal gradient (10-4500 m). The concentrations were in the order of background levels, involving absence of major pollution sources in the high mountain areas. Significant correlations were found between log-transformed concentrations of hexachlorobenzene, alpha- and gamma-hexachlorocyclohexane in soils and total organic content (TOC). In addition, TOC-normalized concentrations of the most volatile OC showed a significant linear dependence with air temperature. This good agreement points to temperature as a significant factor for the retention of long range transported OC in remote ecosystems such as the Andean mountains, although other variables should not be totally excluded. The highest concentrations of OCs were achieved in the sites located at highest altitude and lowest temperature of the dataset. 相似文献
69.
Báez AP Torres Mdel C García RM Padilla HG 《Environmental science and pollution research international》2002,9(4):230-233
A great number of studies on the ambient levels of formaldehyde and other carbonyls in the urban rural and maritime atmospheres have been published because of their chemical and toxicological characteristics, and adverse health effects. Due to their toxicological effects, it was considered necessary to measure these compounds at different sites in the metropolitan area of Mexico City, and to calculate the total rate of photolytic constants and the photolytic lifetime of formaldehyde and acetaldehyde. Four sites were chosen. Sampling was carried out at different seasons and atmospheric conditions. The results indicated that formaldehyde was the most abundant carbonyl, followed by acetone and acetaldehyde. Data sets obtained from the 4 sites were chosen to calculate the total rate of photolysis and the photolytic lifetime for formaldehyde and acetaldehyde. Maximum photolytic rate values were obtained at the maximum actinic fluxes, as was to be expected. 相似文献
70.
Subsoil TPH and other petroleum fractions-contamination levels in an oil storage and distribution station in north-central Mexico 总被引:1,自引:0,他引:1
Many oil industry related sites have become contaminated due to the activities characteristic of this industry, such as oil exploration and production, refining, and petro-chemistry. In Mexico, reported hydrocarbon spills for the year 2000 amounted to 185 203, equivalent to 6252 tons (PEMEX, 2000). The first step for the remediation of these polluted sites is to assess the size and intensity of the oil contamination affecting the subsoil and groundwater, followed by a health risk assessment to establish clean up levels. The aim of this work was to characterize the soil and water in a north-central Mexico Oil Storage and Distribution Station (ODSS), in terms of TPHs, gasoline and diesel fractions, BTEX, PAHs, MTBE, and some metals. Besides, measurements of the explosivity index along the ODSS were made and we describe and discuss the risk health assessment analysis performed at the ODSS, as well as the recommendations arising from it. Considering soils with TPH concentrations higher than 2000 mg kg−1, the contaminated areas corresponding to the railway zone is about 12 776.5 m2, to the south of the storage tanks is about 6558 m2, and to the south of the filling tanks is about 783 m2. Total area to be treated is about 20 107 m2 (volume of 20 107 m3), considering 1 m depth. 相似文献