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At least 289 records · Page 16Linked to original sources
PubMed2006

Analysis of mosses and soils for quantifying heavy metal concentrations in Sicily: a multivariate and spatial analytical approach.

BACKGROUND: The use of vegetal organisms as indicators of contamination of the environment is partially replacing traditional monitoring techniques. Amongst the vegetal organisms available, mosses appear to be good bioindicators and are used for monitoring anthropogenic and natural fall-out on soils. This study has two objectives: the evaluation of the concentrations of heavy metals in soils and mosses of the Sicily Region, in Italy and the identification of the origin of fall-out of heavy metals. METHODS: Mosses and the surface soil were sampled at 28 sites, only the youngest segments of Hylocomium splendens and Hypnum cupressiforme, corresponding to the plant tissues produced during the last 3 years, were taken. The elements Cd, Cu, Ni, Pb and Zn were analysed by ICP-MS and Hg by AAS. Statistical analysis was by PCA and spatial representation by GIS. RESULTS AND DISCUSSION: In the mosses sampled in Sicily, the highest concentrations of Cd were found around the cities of Palermo and Messina. The highest concentrations of Hg were recorded in the northern part of the island between Trapani and Messina, similar to the distribution of Cu. Different areas with the highest concentrations of Ni were found near the south coast, in the vicinity of Palermo and around the Volcano Etna. The highest concentrations of Pb were found in the south-west coast near Agrigento, where important chemical plants and petroleum refineries are located. Except for a few locations, Zn fall-out was found to be evenly distributed throughout Sicily. CONCLUSION: The sites where the concentrations of heavy metals cause greatest concern have been revealed by the PCA analysis and portrayed using GIS. Also of some concern is the diffuse and anthropogenic origin of Hg and Cd. The combined approach of using soil and mosses, together with pedological interpretation and application of multivariate statistical techniques has provided valuable insight into the environmental aspects of heavy metal deposition in a region of southern Europe. RECOMMENDATIONS AND OUTLOOK: Further insight into the deposition of heavy metals will require more detailed sampling of soils and mosses in both new and previous study areas. This needs to be complemented by detailed pedological investigations in the study areas. Future research programmes will address these issues.

Air Pollution↗
PubMed2003

Comparison of analytic approaches for the economic evaluation of new technologies alongside multicenter clinical trials.

BACKGROUND: In reporting economic evaluations of clinical trials, results are often stated without a description of the methodology used to derive the cost estimates. We compared methods for measuring costs from multicenter clinical trials to determine the extent to which the methodology affects results. METHODS: Patient-level data (n = 1849) from 3 multicenter clinical trials of percutaneous coronary revascularization were used to compare 4 methods of estimating costs: 1) hospital charges; 2) hospital charges converted to costs by use of hospital-level cost-to-charge ratios; 3) hospital charges converted to costs by use of department-level cost-to-charge ratios; 4) itemized catheterization laboratory costs with nonprocedural hospital costs generated from department-level cost-to-charge ratios. RESULTS: The method used to approximate costs did not affect the main results of the economic comparisons for any of the trials. The magnitude of the cost estimates and the cost differences between treatment groups varied considerably by method, however. Charges were approximately twice as high as hospital cost estimates. At the patient level, costs generated by use of method 1 were within 10% of those generated by use of method 4 for only 5% of patients, compared with 34% and 22% of patients with methods 2 and 3, respectively. Only method 3 produced estimates of between-group cost differences that were consistently within $500 of the reference standard. CONCLUSION: Cost estimates derived from clinical trials in the cardiovascular arena vary substantially according to accounting methodology. Thus, in reporting the results of economic analyses, a detailed description of cost derivation is necessary, particularly when the absolute magnitude of the cost estimates is important to clinical decision-making or policy-level recommendations. For the purposes of group-level comparisons, conversion of hospital charges to costs on the basis of department-level cost-to-charge ratios appears to represent a reasonable compromise between accuracy and ease of implementation.

Angioplasty, Balloon, Coronary↗
PubMed2001

Analytical approaches to food-based dietary guidelines in the European setting.

OBJECTIVE: To show the effects of statistical approaches of data analysis to be used in the development of Food-Based Dietary Guidelines (FBDG). SETTING: Databases from dietary surveys in 6 European countries. RESULTS: Quantile analysis based on iron intake among adult women resulted in differences among European countries regarding (macro) nutrient intake and consumption of food groups. However, in all countries women in the highest quartile had a higher intake of energy and dietary fibre and a higher intake of most food groups. In developing FBDG adjustment of energy intake is recommended. Discriminant analyses showed that among Dutch women potatoes, red meat, sausages, offal, savoury snacks, eggs and total vegetables were found to be the most predictive for differences in iron intake. Relatively high correlations were observed for iron and dietary fibre and iron and (some) B-vitamins. Examples from cluster and factor analysis showed that this type of analysis considers the complexity of the dietary pattern and could also be a helpful instrument in the development of FBDG. CONCLUSIONS: The use of a nutrient distribution can be used as a minimum approach in developing FBDG. More advanced methods can also be used in addition to set priorities for FBDG and to analyse complete dietary patterns.

Cluster Analysis↗
PubMed2002

Dental health patterns in young adults in Lithuania: an exploratory, analytical approach.

Patterns of variation in experience related to caries and treatment with regard to psychosocial, socio-economic, lifestyle, and oral healthcare-related characteristics were explored. A random sample of 382 (response rate 51%) subjects residing in 10 areas of Lithuania was examined (35 to 44-year-olds). Participants were given a dental examination and asked to complete a structured questionnaire. Experience related to caries and treatment differed with regard to residency and between genders. Analysis of self-reported data elucidated different aspects of psychosocial and socio-economic status and a variety of lifestyle factors. Interrelationships between the studied determinants were also analysed. Different patterns of dental health were revealed for men and women and for urban and rural participants. It can be concluded that factors influencing the dental status of Lithuanians are not only multiple, they seem also to influence dental health in complex ways. An exploratory approach should therefore be considered as a prerequisite to a causal approach of studying caries in populations.

Adult↗
PubMed1983

An analytical approach to the preparation and characterization of subcellular membranes from canine mesenteric arteries.

Subcellular membrane fractions were isolated from dog mesenteric arteries by differential and isopynic sucrose density gradient centrifugations. Isolated membrane fractions were characterized by marker enzyme activities, morphological features and sodium dodecyl sulfate-polyacrylamide gel electrophoretic patterns. Our results show that the microsomal fraction isolated by conventional differential centrifugation was highly heterogenous and contained substantial amount of plasma membranes which could be further enriched as a light density membrane fraction on a discontinuous sucrose density gradient. The microsomal fraction and its subfractions were vesicular in appearance under electron microscope and were capable of binding and actively transporting Ca2+. The binding of Ca2+ and ATP-supported Ca2+-transport in the presence or absence of oxalate paralleled the distribution of plasma membrane marker enzyme activities suggesting that plasma membranes in vascular smooth muscle may play a major role in handling Ca2+ and thus the control of contractile function.

Adenosine Triphosphate↗
PubMed1980

Analytical approaches for determining human exposure to pesticides.

The presence of pesticides, both persistent and biodegradable, in the environment is a problem which is both significant and potentially dangerous to humans. An index of biodegradability is presented which is based on the correlation between environmental stability and fat solubility. Halogenated pesticides are, therefore, both more fat soluble and more resistant to biodegradation, while methylated pesticides are more water soluble and, therefore, more biodegradable. Three methods for detecting low-levels of halogenated pesticides are presented: the Macro, the Micro "Florisil," and the Micro "Silica." A method is also presented to detect these chemicals in blood. Two methods for the detection of nonpersistent, organophosphorus and carbamate insecticides, Cholinesterase inhibition and urinary metabolites, are described. Finally, methods of monitoring human exposure through the detection of phenols, phenoxy acids, alkyl phosphates, and anilines are presented.

Adipose Tissue↗
PubMedDate not supplied

Multidimensional patterns of aging: a cluster-analytic approach.

A person-oriented approach, cluster analysis, was used to define patterns of aging in 335 subjects from the Gothenburg study of 70-year-olds (H-70). Five distinct patterns, based on the domains of well-being, physical health, functional capacity, cognitive abilities, and social contacts, were found, and members of the five groups were followed longitudinally over 9 years. Overall, the majority of the subjects were in relatively high performing groups at age 70. Two of the groups had very low levels on all of the domains. Group membership at age 70 was predictive of later performance, suggesting that there is utility in typologies of aging individuals and/or trajectories of aging. This study supports a multidimensional approach to the study of variability in aging. Refining the description of agers, and of aging, can contribute both to basic understanding of aging processes and to practical matters of meeting the long-term needs of elderly people.

Aged↗
PubMed1995

A statistical analytical approach to decipher information from biological sequences: application to murine splice-site analysis and prediction.

A simple statistical approach for the analysis of biological sequences, such as splice-sites, promoter regions, helices and extended structure forming regions or any other sequence dependent functional entities in proteins, is presented. The approach has been proved useful to develop a method for prediction of such entities in newly available sequences. We first search for invariant sequence features of each functional entity from the experimentally available sequences and identify a set of 'like' sequences with similar sequence features. In the next step, concrete features of sequence entities in terms of occurrences of smaller subsequences are identified at various positions which are used as a knowledge base to select potential functional entities from the identified 'like' sequences. The third step consists of refinement of this pattern learning, statistical improvements of the knowledge base weight matrices, and finally its application to predict functional entities in newly available sequences. Such an analysis is operationally described for murine splice-site predictions. Regions comprising -30 to +30 nucleotides from the splice-junction at the murine splice-sites (donors and acceptors), reported earlier, were analyzed. Invariant sequence-specific features in terms of monomer frequency average were used to identify splice-site-like sequences in the EMBL murine DNA sequence data base. The frequencies of occurrence of mono-, di-, tri- and tetranucleotides in the known splice-sites were studied in comparison with the splice-site-like sequences; the significant differences in their occurrences were extracted as statistical knowledge coded in weight matrices for computer to identify potential splice-sites. The algorithm was refined and a method was developed to predict potential splice-sites in a given murine DNA; the analysis was also extended to human DNA. The success rate of the method to predict correct splice-sites in these species is found to be 80% and 85%, respectively. The major strength of this method lies in reducing significantly the number of false positives which are normally picked up in such analysis.

Algorithms↗
PubMed2000

Quantification of DNA damage by PFGE: development of an analytical approach to correct for the background distribution.

PURPOSE: To analyse the currently existing methods to infer the extent of cellular DNA damage induced by ionizing radiation when the pulsed field gel electrophoresis (PFGE) technique is used. RESULTS AND CONCLUSIONS: PFGE is currently the method of choice for the measurement of radiation-induced double-strand breaks (dsb). For accurate determination of both the yields and distributions of breaks, separation of a large range of fragment sizes is required. In the conventional analysis of PFGE experiments, the background distribution of fractionated molecules is, normally, simply subtracted from the irradiated measured distribution, for each molecular weight region available. This work shows that this approach may lead to incorrect estimation of the breakage frequencies. An alternative approach based on correcting the fitting functions for the actual nonrandom damage present in the control unirradiated samples has been developed.

DNA↗
PubMedDate not supplied

Unifying susceptibility, exposure, and time: discussion of unifying analytic approaches and future directions.

This article reviews design and analysis concepts associated with the following major issues in air pollution epidemiology: (1) time-related determinants of health effects, including duration of exposure and disentangling acute effects and total life-shortening associated with long-term exposure; and (2) the role of geographies of susceptibility and exposure including the relevance and impact of ecologic covariates in the assessment of long-term effects of ambient air pollution. The article identifies the potential contribution associated with improved information in these areas to air pollution policy development and argues that these issues should frame future approaches to assessing the total effects of ambient air pollution.

Air Pollutants↗
PubMed1993

An analytical approach for reducing workplace health hazards through substitution.

Substitution for a harmful chemical implies that the desired function is maintained without using the harmful chemical in question. Improvement can be achieved if a less harmful chemical can be used or the same function obtained by changing the process and eliminating the harmful chemical agent. In 1982, Denmark introduced an authority regulation requiring substitution if functional and economical alternatives exist. This paper summarizes the results of 162 examples of substitution investigated by the Danish Occupational Health Services. The identification and implementation of substitution alternatives is described as an iterative process with seven distinct steps. Several tools that are useful in evaluating alternatives are described, including Hansen solubility parameters and vapor hazard ratios. In addition to the technical issues surrounding substitution, this paper describes the social interactions necessary to include all affected individuals, along with those having the proper expertise in the decision-making process. The use of the described methods may result in a safer work-place by eliminating certain hazardous chemicals or practices that have historically been used in specific industries.

Decision Support Techniques↗
PubMed2001

Comorbidity of psychiatric and substance use disorders in late adolescence: a cluster analytic approach.

Cluster analysis was used to identify subgroups of youths with past-year substance and/or psychiatric disorders (N = 110, mean age 19.0 years). Data for this study came from a community-based, prospective longitudinal investigation of speech/language (S/L) impaired children and matched controls who participated in extensive diagnostic and psychosocial assessments at entry into the study at 5 years of age and again at follow-up. Clustering variables were based on five DSM diagnostic categories assessed at age 19with the University of Michigan Composite International Diagnostic Interview. Using Ward's method, the five binary variables were entered into a hierarchical cluster analysis. An iterative clustering method (K-means) was then used to refine the Ward solution. Finally, a series of analyses of variance (ANOVAs) were run to analyze group differences between clusters on measures of Global Assessment of Functioning (GAF), criminal involvement, anxiety and depressive symptomatology, and frequency of drug use and heavy drinking. The analysis yielded eight replicable cluster groups, which were labeled as follows: (a) anxious (20.9%); (b) anxious drinkers (5.5%); (c) depressed (16.4%); (d) depressed drug abusers (10%); (e) antisocial (16.4%); (f) antisocial drinkers (10%); (g) drug abusers (8.2%); (h) problem drinkers (12.7%). These groups were differentiated by external criteria, thus supporting the validity of our cluster solution. Cluster membership was associated with a history of S/L impairment: A large proportion of the depressed drug abusers and the antisocial cluster group had S/L impairment that was identified at age 5. Clarification of the developmental progress of the youths in these cluster groups can inform our approach to early intervention and treatment.

Adolescent↗
PubMed1977

A systems-analytical approach to macro-evolutionary phenomena.

Two sets of evolutionary phenomena find no explanation through current theory. For the static phenomena (such as homology, homonomy, systematic weight, and "Type") there is no causal base, although these principles are responsible for all phenomena of predictable order in the living world. The dynamic phenomena (such as homodynamy, coadaptation, parallel evolution, orthogenesis, Cartesian transformation, typostrophy, hetermorphosis, systemic mutation, and spontaneous atavism) have no causal explanation, although they are responsible for all directed phenomena in macroevolution. These phenomena share one unifying principle which can be explained by a system theory of evolution based on, but extending, the current synthetic theory. This system theory envisages feedback conditions between genotype and phenotype by which the chances of successful adaptation increase if the genetic units, by insertion of superimposed genes, copy the functional dependencies of those phene structures for which they code. This positive feedback of the adaptive speed (or probability) within a single adaptive direction is compensated by negative feedback in most of the alternative directions. The negative feedback operates as selection not be environmental but by systemic conditions developed by the organization of the organism. The consequences are an imitatively organized system of gene interractions, the rehabilitation of classical systematics, the reality of the "natural system," and, in general, the resolution of the contradiction between neodarwinists and their critics, between reductionists and holists, between "a priori" and "a posteriori" views, between idealism and materialism, and between the notions of freedom and of purpose in evolution.

Biological Evolution↗