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PubMed1990

Occupational and environmental hygiene assessment of fumigations with methyl bromide.

Use of methyl bromide for pest control fumigation may result in adverse exposure to three populations: the actual fumigators; other workers not actually involved in the fumigation; and the general public in the vicinity. The risk of exposure of these three target populations in Switzerland was investigated. The methodology was a combination of occupational hygiene surveys, including a preliminary hazard analysis, with a comprehensive assessment of the safety and health systems in use based on the 'Management Oversight and Risk Tree' (MORT) method [Knox and Eicher, MORT User's Manual, Revision 2. DOE 76-45/4 (1983)]. The target populations most concerned depend on the type of fumigation. Fumigators risk severe accidental exposure although they usually wear personal protection devices. In soil and chamber fumigation, workers not involved in the fumigation may undergo high exposure (75-100 pm for 1 h), far greater than the usual time-weighted average and short-term occupational exposure limits (5-20 ppm range). Occupants of premises adjoining the fumigated buildings may also be exposed to significant concentrations (25-50 ppm for 0.1-2 h). Problems originate mainly from a lack of management controls, failure to apply an appropriate code of practice and the use of personnel who are not properly qualified and trained.

Air Pollutants↗

PubMed1999

[Parameter of evidence-based medicine in health care economics].

In the view of scarcity of resources, economic evaluations in health care, in which not only effects but also costs related to a medical intervention are examined and a incremental cost-outcome-ratio is build, are an important supplement to the program of evidence based medicine. Outcomes of a medical intervention can be measured by clinical effectiveness, quality-adjusted life years, and monetary evaluation of benefits. As far as costs are concerned, direct medical costs, direct non-medical costs and indirect costs have to be considered in an economic evaluation. Data can be used from primary studies or secondary analysis; metaanalysis for synthesizing of data may be adequate. For calculation of incremental cost-benefit-ratios, models of decision analysis (decision tree models, Markov-models) often are necessary. Methodological and ethical limits for application of the results of economic evaluation in resource allocation decision in health care have to be regarded: Economic evaluations and the calculation of cost-outcome-rations should only support decision making but cannot replace it.

Costs and Cost Analysis↗

PubMed2005

The use of forests for the purpose of tourism: the case of Belek Tourism Center in Turkey.

The main aim of this article is to examine and review the usage of forests for the purpose of tourism in Turkey with the case study of Antalya-Belek. The use and conversion of forest lands is central to tourism development. Land use change is responsible for the majority of the negative environmental impacts of tourism on natural resources. Worldwide, forests and coastal zones are converted for the construction of tourist facilities. The rapid emergence of mass tourism development in Turkey, encouraged without considering protection and sustainable use of natural and cultural resources, has resulted in serious problems in forest areas. This paper is particularly concerned with land use change in forests (or deforestation) created by the allocation of forest lands to build tourist facilities. In Belek, a tourism center located in Antalya province's coastal areas and the fastest growing destination of the country, all tourist facilities have been established in forest lands under the status of conservation forest. Today, the Belek Conservation Forest is under severe pressure from tourism.

Conservation of Natural Resources↗

PubMed1999

Ecosystem of the Anticolana Valley.

The results of an integrated environmental study on the geological, hydrogeological and ecological features of the area of formation of the low mineral content water of Fiuggi are briefly presented. The research programme, that was started in 1996 and is now in its final phase, was aimed at the following: (a) identifying the geological-structural limits of the hydrogeological basin; (b) building a model of the deep water circulation that should include an analysis of the rainfall and of the water balance, and (c) determining the vulnerable characteristics of the aquifer in relation to the human impact and setting up a monitoring system to control the different environmental parameters.

Ecosystem↗

PubMed2003

Legionella busanensis sp. nov., isolated from cooling tower water in Korea.

Three Legionella-like micro-organisms, isolated from cooling tower water of a building in Busan, Korea, were characterized by a variety of biochemical and molecular phylogenetic tests. Analyses of whole-cell fatty acids and results of biochemical tests revealed that these three isolates are distinct from previously described Legionella species. Furthermore, results of comparative analyses of 16S rDNA (1476-1488 bp), mip (408 bp) and rpoB (300 bp) sequences also confirmed that these strains represent a novel species within the genus Legionella. The 16S rDNA sequences of the three Korean isolates had similarities of less than 95.8% to other Legionella species. Phylogenetic trees formed by analysis of the 16S rRNA, rpoB and mip genes revealed that the isolates formed a distinct cluster within the genus Legionella. Based on the evaluated phenotypic and phylogenetic characteristics, it is proposed that these Korean isolates from water be classified as a novel species, Legionella busanensis sp. nov.; the type strain is strain K9951T (=KCTC 12084T =ATCC BAA-518T).

Bacterial Proteins↗

PubMedDate not supplied

Faster isosurface ray tracing using implicit KD-trees.

The visualization of high-quality isosurfaces at interactive rates is an important tool in many simulation and visualization applications. Today, isosurfaces are most often visualized by extracting a polygonal approximation that is then rendered via graphics hardware or by using a special variant of preintegrated volume rendering. However, these approaches have a number of limitations in terms of the quality of the isosurface, lack of performance for complex data sets, or supported shading models. An alternative isosurface rendering method that does not suffer from these limitations is to directly ray trace the isosurface. However, this approach has been much too slow for interactive applications unless massively parallel shared-memory supercomputers have been used. In this paper, we implement interactive isosurface ray tracing on commodity desktop PCs by building on recent advances in real-time ray tracing of polygonal scenes and using those to improve isosurface ray tracing performance as well. The high performance and scalability of our approach will be demonstrated with several practical examples, including the visualization of highly complex isosurface data sets, the interactive rendering of hybrid polygonal/isosurface scenes, including high-quality ray traced shading effects, and even interactive global illumination on isosurfaces.

Algorithms↗

PubMed2001

A multicenter case-control study in Italy on hematolymphopoietic neoplasms and occupation.

We conducted a population-based, case-control study on hematolymphopoietic malignancies in 12 areas in Italy to investigate associations between different hematolymphopoietic malignancies and exposure to solvents and pesticides. We collected all incident cases 20-74 years of age from 12 areas, with a combined population of approximately 7 million residents. The control group was formed by a random sample of the study population. Data presented in this paper refer to 2,737 interviewed cases of 3,357 eligible cases and to 1,779 of 2,391 eligible controls. We analyzed risks associated with occupation using job-title information to evaluate disease pattern according to job category. An earlier publication presented results for women; here, we report the findings for men and discuss the overall patterns in both genders. The most consistent overall finding was an approximate doubling in relative risk for all four types of malignancies among male managers and related occupations. Several additional occupations were associated with elevated risk of one or more malignancies among men. These included cooks, waiters, and bartenders, and building caretakers and cleaners, for non-Hodgkin's lymphoma; textile workers and machinery fitters for Hodgkin's lymphoma; metal processors, material handlers, rubber workers, and painters for leukemia; and hairdressers, metal processors, tailors, electrical workers, and plumbers for multiple myeloma. The finding of increased risk of non-Hodgkin's lymphoma among both male and female cooks, waiters, and bartenders has not been previously reported; nor has the elevated risk of leukemia among material handlers. Among people engaged in agriculture, those employed as tractor drivers and as "orchard, vineyard, and related tree and shrub workers" appeared to be at increased risk for hematolymphopoietic malignancies.

Adult↗

PubMed2001

From data collection to knowledge data discovery: a medical application of data mining.

Prison inmates are exposed to a variety of major risk factors (psychiatric disorders, suicide attempts, illicit drug use). From 1986 to 1996, the USA prison population more than doubled while in France, it increased from 35655 in 1980 to 51623 in 1995. In spite of these findings, very little information concerning the inmates population is available. At the present time, there is a desire to adopt a policy based on the prevention of recidivism, on adequate release planning and referrals to community-based services. The aim of the RAPPEL project was to build an information system for assessing the social and health status of prison inmates. The pilot project was set up at the prison of Loos and allowed the collection and analysis of nearly 15000 records. The aim of this paper is to present the extension of the project consisting in developing a regional network grouping 11 jails. Information locally available will serve as the basis for the information system of regional jails. Data mining techniques will provide solutions for the extraction of new information. Three data mining tools were experimented : association rules, classification trees and clustering. Further extension consists in a distributed approach allowing direct access to the information system by WEB tools.

Classification↗

PubMed2002

Phylogenetic relationships, evolution of broodcare behavior, and geographic speciation in the wrasse tribe Labrini.

The family Labridae is a large assemblage of marine fish composed of about 580 species in 82 genera distributed in tropical and temperate marine waters around the world. Several subgroups, currently classified as tribes, have been identified in this large family, yet only a few phylogenetic analyses have been performed on labrid clades. We confirm monophyly of the labrid tribe Labrini and propose a phylogeny of the 23 species of the genera Acantholabrus, Centrolabras, Ctenolabrus, Labrus, Lappanella, Symphodus, Tautoga, and Tautogolabrus occurring in the eastern and western Atlantic and the Mediterranean. We analyzed a 577-bp segment of the mitochondrial 16S rDNA and a 506-bp segment of the mitochondrial control region in 22 species, for a total of up to 1069 bp per species. We used both parsimony and likelihood approaches under a variety of assumptions and models to generate phylogenetic hypotheses. The main features of the molecular phylogeny for the Labrini turned out to be the same for the two algorithms applied. The tree structure is similar to a previous, unpublished morphological phylogeny for a subset of labrine species. Estimated divergence times of the Labrini based on fossils and a molecular clock range from about 15 mya for the deepest splits to less than 1 mya for younger clades. Biogeographic patterns of the Symphodus species group and the genus Labrus are dominated by speciation events driven by the closing and opening of the Mediterranean Sea and periodic glaciation events during the past 1 million years. The Labrini are the only clade in the entire Labridae that exhibit nest-building and broodcare behavior. We use the phylogeny to show that similar broodcare behavior has evolved twice in the labrine fish and discuss scenarios for the evolution of broodcare from the diandric protogynous hermaphroditism found in ancestral labrines and many other wrasses.

Animals↗

PubMed2006

Bayesian estimation of species richness from quadrat sampling data in the presence of prior information.

We consider the problem of estimating the number of species of an animal community. It is assumed that it is possible to draw up a list of species liable to be present in this community. Data are collected from quadrat sampling. Models considered in this article separate the assumptions related to the experimental protocol and those related to the spatial distribution of species in the quadrats. Our parameterization enables us to incorporate prior information on the presence, detectability, and spatial density of species. Moreover, we elaborate procedures to build the prior distributions on these parameters from information furnished by external data. A simulation study is carried out to examine the influence of different priors on the performances of our estimator. We illustrate our approach by estimating the number of nesting bird species in a forest.

Animals↗

PubMed2004

Tropical geometry of statistical models.

This article presents a unified mathematical framework for inference in graphical models, building on the observation that graphical models are algebraic varieties. From this geometric viewpoint, observations generated from a model are coordinates of a point in the variety, and the sum-product algorithm is an efficient tool for evaluating specific coordinates. Here, we address the question of how the solutions to various inference problems depend on the model parameters. The proposed answer is expressed in terms of tropical algebraic geometry. The Newton polytope of a statistical model plays a key role. Our results are applied to the hidden Markov model and the general Markov model on a binary tree.

Algorithms↗

PubMed2001

Threading structural model of the manganese-stabilizing protein PsbO reveals presence of two possible beta-sandwich domains.

The manganese-stabilizing protein (PsbO) is an essential component of photosystem II (PSII) and is present in all oxyphotosynthetic organisms. PsbO allows correct water splitting and oxygen evolution by stabilizing the reactions driven by the manganese cluster. Despite its important role, its structure and detailed functional mechanism are still unknown. In this article we propose a structural model based on fold recognition and molecular modeling. This model has additional support from a study of the distribution of characteristics of the PsbO sequence family, such as the distribution of conserved, apolar, tree-determinants, and correlated positions. Our threading results consistently showed PsbO as an all-beta (beta) protein, with two homologous beta domains of approximately 120 amino acids linked by a flexible Proline-Glycine-Glycine (PGG) motif. These features are compatible with a general elongated and flexible architecture, in which the two domains form a sandwich-type structure with Greek key topology. The first domain is predicted to include 8 to 9 beta-strands, the second domain 6 to 7 beta-strands. An Ig-like beta-sandwich structure was selected as a template to build the 3-D model. The second domain has, between the strands, long-loops rich in Pro and Gly that are difficult to model. One of these long loops includes a highly conserved region (between P148 and P174) and a short alpha-helix (between E181 and N188)). These regions are characteristic parts of PsbO and show that the second domain is not so similar to the template. Overall, the model was able to account for much of the experimental data reported by several authors, and it would allow the detection of key residues and regions that are proposed in this article as essential for the structure and function of PsbO.

Algorithms↗

PubMed1999

How to design a connectionist holistic parser.

Connectionist holistic parsing offers a viable and attractive alternative to traditional algorithmic parsers. With exposure to a limited subset of grammatical sentences and their corresponding parse trees only, a holistic parser is capable of learning inductively the grammatical regularity underlying the training examples that affects the parsing process. In the past, various connectionist parsers have been proposed. Each approach had its own unique characteristics, and yet some techniques were shared in common. In this article, various dimensions underlying the design of a holistic parser are explored, including the methods to encode sentences and parse trees, whether a sentence and its corresponding parse tree share the same representation, the use of confluent inference, and the inclusion of phrases in the training set. Different combinations of these design factors give rise to different holistic parsers. In succeeding discussions, we scrutinize these design techniques and compare the performances of a few parsers on language parsing, including the confluent preorder parser, the backpropagation parsing network, the XERIC parser of Berg (1992), the modular connectionist parser of Sharkey and Sharkey (1992), Reilly's (1992) model, and their derivatives. Experiments are performed to evaluate their generalization capability and robustness. The results reveal a number of issues essential for building an effective holistic parser.

Artificial Intelligence↗

PubMed2006

Quantitative ethnobotany in an atlantic forest fragment of northeastern Brazil: implications to conservation.

An ethnobotanical study was executed in the rural community of the Municipality of "Rio Formoso", starting from the forest inventory accomplished in an Atlantic Forest remnant adjacent to the studied community. Using the methodology of quantitative ethnobotany allied to the ecological parameters (richness, relative frequency, relative density, relative dominance and importance value index) the following results were obtained: 42 inventoried species gathered in 26 families, presented from 1 to 27 means of use for the community. The largest use of the plants is related to obtaining wood in order to be used in house building, firewood production and charcoal. The largest use value was attributed to the Vouacapoua virgilioides (Kunth) Kuntze. The most frequent species were Tapirira guianensis Aubl. (Anacardiaceae), Thyrsodium schomburgkianum Benth. (Anacardiaceae), Schefflera morototoni (Aubl.) Maguire, Steyem. & Frodin (Araliaceae) and Dialium guianense (Aubl.) Sandwith. (Leg-Caesalpinioideae).

Atlantic Ocean↗

PubMed1986

Random-clone strategy for genomic restriction mapping in yeast.

An approach to global restriction mapping is described that is applicable to any complex source DNA. By analyzing a single restriction digest for each member of a redundant set of lambda clones, a data base is constructed that contains fragment-size lists for all the clones. The clones are then grouped into subsets, each member of which is related to at least one other member by a significant overlap. Finally, a tree-searching algorithm seeks restriction maps that are consistent with the fragment-size lists for all the clones in each subset. The feasibility of the approach has been demonstrated by collecting data on 5000 lambda clones containing random 15-kilobase inserts of yeast DNA. It is shown that these data can be analyzed to produce regional maps of the yeast genome, extending in some cases for over 100 kilobases. In combination with hybridization probes to previously cloned genes, these local maps are already useful for defining the physical arrangement of closely linked genes. They may in the future serve as building blocks for the construction of a continuous global map.

Chromosome Mapping↗

PubMed2000

Approximate maximum entropy joint feature inference consistent with arbitrary lower-order probability constraints: application to statistical classification

We propose a new learning method for discrete space statistical classifiers. Similar to Chow and Liu (1968) and Cheeseman (1983), we cast classification/inference within the more general framework of estimating the joint probability mass function (p.m.f.) for the (feature vector, class label) pair. Cheeseman's proposal to build the maximum entropy (ME) joint p.m.f. consistent with general lower-order probability constraints is in principle powerful, allowing general dependencies between features. However, enormous learning complexity has severely limited the use of this approach. Alternative models such as Bayesian networks (BNs) require explicit determination of conditional independencies. These may be difficult to assess given limited data. Here we propose an approximate ME method, which, like previous methods, incorporates general constraints while retaining quite tractable learning. The new method restricts joint p.m.f. support during learning to a small subset of the full feature space. Classification gains are realized over dependence trees, tree-augmented naive Bayes networks, BNs trained by the Kutato algorithm, and multilayer perceptrons. Extensions to more general inference problems are indicated. We also propose a novel exact inference method when there are several missing features.

Journal Article↗

PubMed2002

Towards automatic clustering of protein sequences.

Analyzing protein sequence data becomes increasingly important recently. Most previous work on this area has mainly focused on building classification models. In this paper, we investigate in the problem of automatic clustering of unlabeled protein sequences. As a widely recognized technique in statistics and computer science, clustering has been proven very useful in detecting unknown object categories and revealing hidden correlations among objects. One difficulty that prevents clustering from being performed directly on protein sequence is the lack of an effective similarity measure that can be computed efficiently. Therefore, we propose a novel model for protein sequence cluster by exploring significant statistical properties possessed by the sequences. The concept of imprecise probabilities are introduced to the original probabilistic suffix tree to monitor the convergence of the empirical measurement and to guide the clustering process. It has been demonstrated that the proposed method can successfully discover meaningful families without the necessity of learning models of different families from pre-labeled "training data".

Algorithms↗

PubMed2005

[Recognition of occupational cancers: review of existing methods and perspectives].

Occupational risk factors represent a significant part of cancer causes and are involved in all type of cancers. Nonetheless, the frequency of these cancers is largely under-estimated. Parallel to the epidemiological approach (collective), the concept of occupational cancer is often linked (at the individual level) to the compensation of occupational diseases. To give rise to a financial compensation, the occupational origin of the exposition has to be established for a given cancer. Whatever the method used to explore an occupational cause, the approach is that of an imputation. The aim of this work is to synthesize and describe the main principles of recognition of occupational cancers, to discuss the limits of available methods and to consider the research needed to improve these methods. In France, the recognition of a cancer's occupational origin consists in tables of occupational diseases that are based on presumption of causality. These tables consist in medical, technical and administrative conditions that are necessary and sufficient for the recognition of an occupational disease and its financial compensation. Whenever causality presumption does not apply, imputation is based on case analyses run by experts within regional committees of occupational diseases recognition that lack reproducibility. They do not allow statistical quantization and do not always take into account the weight of associated factors. Nonetheless, reliability and validity of the expertise could be reinforced by the use of formal consensus techniques. This process could ideally lead to the generation of decision-making algorithms that could guide the user towards the decision of imputing or not the cancer to an occupational exposure. This would be adapted to the build-up of new tables. The imputation process would be better represented by statistical methods based on the use of Bayes' theorem. The application of these methods to occupational cancers is promising but remains limited due to the lack of epidemiological data. Acquiring these data and diffusing these methods should become research and development priorities in the cancer field.

Causality↗