Search results for "sampling"
showing 10 items of 788 documents
Temporal variability of airborne bacterial community structure in an urban area
2006
International audience; Temporal airborne bacterial genetic community structure and meteorological factors were analysed above an urban area in the northwest of France from December 2003 to April 2004 with a sampling strategy considering different time intervals (from an hour to a month). Principal component analysis (PCA) of B-ARISA (Bacterial-Automated Ribosomal Intergenic Spacer Analysis) profiles revealed a hierarchy in the temporal variability of bacterial community: daily<weekly<seasonal. Co-inertia analysis between B-ARISA data and meteorological factors demonstrated the correlation between the seasonal variability in the bacterial community and climatic conditions such as temperatur…
Spatial diversity of chlorine residual in a drinking water distribution system: application of an integrated fuzzy logic technique
2014
A reduction in the concentration of chlorine, which is used as a chemical disinfectant for water in drinking water distribution systems, can be considered to be an index of the progressive deterioration of water quality. In this work, attention is given to the spatial distribution of the residual chlorine in drinking water distribution systems. The criterion for grouping the water-quality parameters normally used is highly subjective and often based on data that are not correctly identified. In this paper, a cluster analysis based on fuzzy logic is applied. The advantage of the proposed procedure is that it allows a user to identify (in an automatic way and without any specific assumption) …
Volcanic plume monitoring at Mount Etna by diffusive (passive) sampling
2004
[1] This paper reports the use of diffusive tubes in determining HF, HCl, and SO2 in the volcanic plume of Mount Etna in an attempt to highlight the potential of this method in studying volcanoes. In a first application a network of 18 diffusive tubes was installed on Etna's flanks, aimed at evaluating the atmospheric dispersion of the volcanic plume on a local scale. Results showed a monotonic decrease in volatile air concentrations with distance from the craters (HF from 0.15 to <0.003 μmol m−3, HCl from 2 to <0.01 μmol m−3, and SO2 from 11 to 0.04 μmol m−3), revealing the prevalently volcanic contribution. Matching of SO2/HCl and HCl/HF volatile ratios with contemporaneous measurements a…
Il disegno campionario e il piano di rilevazione nell’indagine sui turisti incoming in partenza dalla Sicilia e dalla Sardegna: il campionamento spaz…
2011
This paper aims to describe the sample design and the survey plan used in the survey on incoming tourism in Sicily and Sardinia. The specific goals of the survey are related: a) to the measurement and the analysis of un-observed tourism; b) to the evaluation of tourist mobility within the two Islands; c) to the analysis of some key-factors related to the holyday experience of tourists. It is well known that regional tourists are very difficult-to-reach populations and the problems in sampling human mobile populations derive from the absence of a list of units component units (frame). Despite these issues are well-known in literature under the broader categories of hard to reach, or hidden, …
Predicting soil loss in central and south Italy with a single USLE-MM model
2018
Purpose: The USLE-MM estimates event normalized plot soil loss, Ae,N, by an erosivity term given by the runoff coefficient, QR, times the single-storm erosion index, EI30, raised to an exponent b1> 1. This modeling scheme is based on an expected power relationship, with an exponent greater than one, between event sediment concentration, Ce, and the EI30/Pe(Pe= rainfall depth) term. In this investigation, carried out at the three experimental sites of Bagnara, Masse, and Sparacia, in Italy; the soundness of the USLE-MM scheme was tested. Materials and methods: A total of 1192 (Ae,N, QREI30) data pairs were used to parameterize the model both locally and considering all sites simultaneously. …
Cluster-based active learning for compact image classification
2010
In this paper, we consider active sampling to label pixels grouped with hierarchical clustering. The objective of the method is to match the data relationships discovered by the clustering algorithm with the user's desired class semantics. The first is represented as a complete tree to be pruned and the second is iteratively provided by the user. The active learning algorithm proposed searches the pruning of the tree that best matches the labels of the sampled points. By choosing the part of the tree to sample from according to current pruning's uncertainty, sampling is focused on most uncertain clusters. This way, large clusters for which the class membership is already fixed are no longer…
Biological indices applied to benthic macroinvertebrates at reference conditions of mountain streams in two ecoregions (Poland, the Slovak Republic)
2013
The study was carried out from 2007 to 2010 in two ecoregions: the Carpathians and the Central Highlands. The objectives of our survey were to test the existing biological index metric based on benthic macroinvertebrates at reference conditions in the high- and mid-altitude mountain streams of two ecoregions according to the requirements of the EU WFD and to determine which environmental factors influence the distribution of benthic macroinvertebrates. Our results revealed statistically significant differences in the values of the physical and chemical parameters of water as well as the mean values of metrics between the types of streams at the sampling sites. RDA analysis showed that the t…
The behaviour of non consumer of organic food: suggestions on marketing strategies to attract new market segments
2013
Oggi le produzioni agricole biologiche sono in netta crescita sia a livello internazionale che nazionale. Tra le regioni italiane la Sicilia rappresenta la principale area di produzione e si colloca all’ultimo posto relativamente ai consumi. Attraverso un’indagine pilota nella citta di Palermo, si e voluto indagare, sui motivi del mancato acquisto di prodotti biologici per comprendere quali sono le leve del marketing mix su cui e possibile intervenire per attrarre nuovi segmenti di mercato. L’indagine e stata realizzata intervistando un campione di non-consumatori di alimenti biologi presso alcuni supermercati della citta. I campioni, degli intervistati e dei supermercati, sono stati selezi…
Interdisciplinary consensus on the uses and technique of MR-guided vacuum-assisted breast biopsy (VAB): results of a European consensus meeting.
2009
Abstract Purpose Quality assurance of MR-guided vacuum-assisted breast biopsy (VAB). Method A consensus was achieved based on the existing literature and experience of an interdisciplinary group comprising European specialists in breast imaging and VAB. Results Full imaging work-up must be completed according to existing standards before an indication for MR-guided VAB is established. The procedure should be reserved for lesions demonstrable by MRI alone. Acquisition of >24 cores (11-Gauge) should be routinely attempted, with the intention of sufficiently removing small lesions for accurate diagnosis. Following biopsy the patient should be re-imaged to demonstrate the biopsy site and its pr…
Detection of protection benefits for predatory fishes depends on census methodology
2021
Marine protected areas (MPAs) are used as fisheries management and conservation tools. Well-enforced no-take zones allow the rebuilding of natural populations of exploited species; however, there is still controversy on the role of buffer zones. The effectiveness of MPAs could be underestimated, as fish population assessments depend largely on traditional methodologies that have difficulties in detecting predatory fish because of their low abundances, their patchy distribution, and their reaction to the presence of divers. The performance of different census methods was compared in assessing the protection benefits for large predatory fishes under different protection levels (i.e. no-take a…