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1.
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
2.
Baumann Matthias Israel Christoph Piquer-Rodríguez María Gavier-Pizarro Gregorio Volante José Norberto Kuemmerle Tobias 《Regional Environmental Change》2017,17(4):1179-1191
Regional Environmental Change - The dry forests of Latin America are among the most dynamic deforestation frontiers in the world and are important carbon and biodiversity reservoirs. Our knowledge... 相似文献
3.
Verónica I. Pierini Norberto Bartoloni Silvia E. Ratto 《Environment, Development and Sustainability》2018,20(6):2795-2809
Closed landfills need after-closure rehabilitation. The chosen option should ensure greenhouse gases release, from the landfill, is not promoted once settled. The objective of this study was to estimate and confront, during different seasons, CH4, CO2 and N2O emissions under three vegetation covers in a closed landfill in Buenos Aires, Argentina. CH4 (methane), CO2 (carbon dioxide) and N2O (nitrous oxide) emissions from landfill’s technosol under spontaneous vegetation (control), Pennisetum purpureum and Miscanthus giganteus (biomass crops), were quantified with non-steady-state non-flow-through chambers, in July 2014 and from February to July 2015. A linear regression analysis was performed to relate the variables “flux of a gas” and “concentration of that gas” from the 3 treatments and 6 dates, separating the 5 sampling times. A high correlation between concentrations and fluxes of CO2 and N2O was found, but no correlation was established for CH4. Mean emissions (2014–2015) varied from: ?2.3 to 639.41 mgCH4 m?2 day?1, 3884 to 46,365 mgCO2 m?2 day?1 and 0.40 to 14.59 mgN2O m?2 day?1. Vegetation covers had no significant effect on CH4 and N2O concentration in time, but they had on CO2 concentration. Season of the year had a significant effect on concentration of the three gases. This is the first study on CH4, CO2 and N2O emissions from a landfill closed 27 years ago covered with biomass crops. 相似文献
4.
Francesco Nazzi Renzo Bortolomeazzi Giorgio Della Vedova Fabio Del Piccolo Desiderato Annoscia Norberto Milani 《Die Naturwissenschaften》2009,96(2):309-314
The mite Varroa destructor Anderson & Trueman is a parasite of the honeybee Apis mellifera L. and represents a major threat for apiculture in the Western world. Reproduction takes place only inside bee brood cells
that are invaded just before sealing; drone cells are preferred over worker cells, whereas queen cells are not normally invaded.
Lower incidence of mites in queen cells is at least partly due to the deterrent activity of royal jelly. In this study, the
repellent properties of royal jelly were investigated using a lab bioassay. Chemical analysis showed that octanoic acid is
a major volatile component of royal jelly; by contrast, the concentration is much lower in drone and worker larval food. Bioassays,
carried out under lab conditions, demonstrated that octanoic acid is repellent to the mite. Field studies in bee colonies
confirmed that the compound may interfere with the process of cell invasion by the mite. 相似文献
5.
Norberto Asensio Amanda H. Korstjens Filippo Aureli 《Behavioral ecology and sociobiology》2009,63(5):649-659
The adjustment to deal with intragroup food competition is probably the most plausible explanation of high levels of fission–fusion
dynamics. However, studies did not always support expected relations between food availability, ranging costs, and subgroup
size. We used several levels of analysis differing in the time and spatial scale in order to investigate this explanation
in spider monkeys. In our study, subgroups were larger when food availability was higher across most levels of analyses used.
We also found a fine-scale adjustment: compared to the food patch previously visited, spider monkeys traveled to larger patches
just after fusions. This was not without an immediate travel cost: the interpatch distance and travel time after a fusion
were longer than that before the fusion. This rapid adjustment shows the flexibility that fission–fusion dynamics can offer.
Spider monkeys are in large subgroups only when food conditions are favorable, as evidenced by the fact that at all the other
time-scale levels larger subgroups did not experience greater ranging costs than smaller subgroups. Our results indicate that
on the whole spider monkeys successfully minimize ranging costs by fission and fusion of subgroups. 相似文献
6.
New Fe-immobilized natural bentonite plate used as photo-Fenton catalyst for organic pollutant degradation 总被引:1,自引:0,他引:1
Novel photo-Fenton catalysts were prepared by immobilizing iron species on commercial bentonite plates via two methods: (1) ion exchange reaction (Fe3+ vs. Na+) by aqueous suspension powder-clay/FeCl3 followed by plate preparation, and (2) forced hydrolysis of Fe(NO3)3 onto a prefabricated clay plate. The last method led to a more photo-active Fe-oxide/bentonite plate. This material allowed, at a non-adjusted initial pH of 5.5 and in the presence of H2O2, the total degradation of resorcinol and 55% mineralization in 80 and 100 min of irradiation, respectively. The reached degradation percentages were correlated to the presence of dissolved iron, demonstrating that in these processes, the homogeneous photo-Fenton reactions were mainly responsible for the resorcinol elimination.Likewise, in slurry system, where clay has normally an increased surface area, there was no increase in activity because of a reduced leached iron probably due to the diminished light penetration in the suspension. Despite the lower surface area, in comparison to that of the slurry, the clay plates have the advantage, as heterogeneous photo-catalysts, that separation of the reaction media after treatment is not needed, and thus, a potential use for batch and continuous reaction systems is proposed. 相似文献
7.
Luca Marmo Norberto Piccinini Luca Fiorentini 《Journal of Loss Prevention in the Process Industries》2013,26(1):215-224
The Authors of this paper are the technical experts that were entrusted by the Public Prosecutor to conduct the technical inquiry into the accident that occurred in the ThyssenKrupp plant in Torino on December 6, 2007. The paper contains the results of the inquiry under the above mentioned point of view. The dynamics of the accident, the main causes and the consequences have been defined.This was an unusual accident from which important lessons can be learned. On December 6, a modest fire developed in the entry section of a pickling and annealing line in the TK plant in Turin. The eight workers on duty seized the firefighting equipment and started to try to extinguish the fire. The workers had portable fire extinguishers and a fire hydrant, so they had to get close to the fire to fight it. Suddenly, a violent jet fire, caused by the rupture of a hydraulic circuit, occurred. The flame instantaneously struck the eight workers while they were still fighting the fire. Seven workers suffered very serious burns, one died instantaneously while the other six had over the following month. One of the workers, who was partly protected by an operating machine, suffered only minor burns and survived. The paper contains some important lessons that have been learned from the present case, which demonstrate that the fire risk at pickling and annealing lines has generally been underestimated by the steel industry. The fire risk due to hydraulic actuators is also evident and new fire fighting strategies are suggested. 相似文献
8.
Total mercury and methylmercury concentrations in fish from the Mojana region of Colombia 总被引:1,自引:0,他引:1
Marrugo-Negrete J Verbel JO Ceballos EL Benitez LN 《Environmental geochemistry and health》2008,30(1):21-30
Total mercury (T-Hg) and methylmercury (MeHg) concentrations have been measured in the muscle tissue of 16 fish species consumed
in the Mojana region of Colombia. T-Hg analysis was performed by cold-vapor atomic-absorption spectroscopy (CV-ASS) and MeHg
analysis by gas chromatography with electron-capture detection. Higher T-Hg and MeHg concentrations were detected in carnivorous
species (T-Hg = 0.371 ± 0.172 (μg g−1 fresh wt, MeHg = 0.346 ± 0.171 μg g−1 fresh wt) than in non-carnivorous fish (T-Hg = 0.155 ± 0.108 μg g−1 fresh wt, MeHg = 0.146 ± 0.102 μg g−1 fresh wt). In the different species mercury was present almost completely as the methylated form, with percentages between
80.5 and 98.1% (mean 92.0 ± 3.4%). In 13.5% of fish-tissue samples T-Hg concentrations exceeded the maximum level recommended
by the World Health Organization for human consumption (Hg = 0.5 μg g−1 fresh wt). Although mean T-Hg concentrations in all fish samples (0.269 ± 0.181 μg g−1 fresh wt) did not exceed this limit, risk assessment suggested that the consumption of 0.12 kg fish day−1 could increase the risk of mercury poisoning of the inhabitants of this region. 相似文献
9.
Juliana Ferreira Floriano Natan Roberto de Barros José Luiz Ferreira Cinman Rosangela Gonçalves da Silva Augusto Villela Loffredo Felipe Azevedo Borges Ana Maria Queiros Norberto Ana Laura Destro Chagas Bruna Cambraia Garms Carlos Frederico de Oliveira Graeff Rondinelli Donizetti Herculano 《Journal of Polymers and the Environment》2018,26(6):2281-2289
Ketoprofen is an analgesic with potent anti-inflammatory activity against acute inflammation, subacute inflammation, for the acute and long-term treatment of various inflammatory pathologies, as rheumatoid arthritis and colonic adenocarcinoma. In order to minimize the incidence of systemic events related to ketoprofen, the transdermal drug delivery system development has been most important. The advantages of using natural rubber latex membranes include not only the reduction of adverse systemic events, but also the suitability of the low cost of the material together with its physicochemical properties such as flexibility, mechanical stability, surface porosity and water vapor permeability, and besides being a biocompatible material also presents biological activity to stimulate the angiogenesis, being able to be used in tissue repair. This study demonstrated that ketoprofen was successfully incorporated into natural latex membranes for drug delivery. FTIR indicated that the drug did not interact chemically with the membrane. Moreover, the natural latex membranes released 60% of the ketoprofen incorporated in 50 h. SEM images indicated that a portion of the drug was present on the membrane surface, being this portion responsible for the burst release. The tensile tests showed that the addition of the drug into the natural latex membrane did not influence on the polymer mechanical behavior. In addition, drug-natural latex membranes presented no red blood cell damaging effects. Our data shows that the ketoprofen loaded natural latex membranes is a promising system for sustained drug delivery which can be used to minimize the adverse side effects of high dose systemic drug delivery. 相似文献
10.
Roveri Vinicius Guimarães Luciana Lopes Toma Walber Correia Alberto Teodorico 《Environmental science and pollution research international》2021,28(46):65595-65609
Environmental Science and Pollution Research - In some Brazilian coastal cities, it is common to observe ‘black tongues’ in beaches, i.e. a mixture of urban runoff and untreated... 相似文献