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At least 289 records · Page 16Linked to original sources
PubMed2001

Triage nurses' clinical decision making. An observational study of urgency assessment.

BACKGROUND: Researchers have described both the various decision tasks performed by triage nurses using self-report methods and identified time as a factor influencing the quality of triage decisions. However, little is known about the decision tasks performed by triage nurses when making acuity assessments, or the factors influencing triage duration in the real world. AIMS: The aims of this study were to: describe the data triage nurses collect from patients in order to allocate a triage priority using the Australasian Triage Scale (ATS); describe the duration of nurses' decision making for ATS categories 2-5; and to explore the impact of patient and nurse variables on the duration of the triage nurses' decision making in the clinical setting. DESIGN: A structured observational study was employed to address the research aims. Observational data was collected in one adult emergency department located in metropolitan Melbourne, Australia. A total of 26 triage nurses consented and were observed performing 404 occasions of triage. Data was collected by a single observer using a 20-item instrument that recorded the performance frequencies of a range of decision tasks and a number of observable patient, nurse and environmental variables. Additionally, the nurse-patient interaction was recorded as time in minutes. RESULTS: It was found that there was limited use of objective physiological data collected by the nurses' in order to decide patient acuity, and large variability in the duration of triage decisions observed. In addition, analysis of variance indicated strong evidence of a true difference between triage duration and a range of nurse, patient and environmental variables. CONCLUSION: These findings have implications for the development of practice standards and triage education. In particular, it is argued that practice standards should include routine measurement of physiological parameters in all but the collapsed or obviously unwell patient, where further delay may impede the delivery of time-critical intervention. Furthermore, the inclusion of arbitrary time frames for triage assessment in practice standards are not an appropriate method of evaluating triage decision making in the real world.

Adult↗
PubMed1990

Prediction of sugar behaviour.

The purpose of this study was to identify determinants of sugar consumption in terms of personal and environmental variables. The study group comprised 127 14-year-old schoolchildren in Aarhus. Data were collected by means of semistructured interviews and self-administered questionnaires. Forward selection multiple regression analysis was the analytical method of choice, and the relationships were interpreted using the problem behaviour theory. The results showed that environmental variables were more important than personal variables for sugar consumption. In particular, degree of peer orientation was closely linked to sugar consumption (beta = 0.29). The full model including both sets of variables explained 14.5 per cent of the variance in sugar consumption. Sugar consumption seems to be a way of demonstrating adherence to and identification with peer group norms for adolescents at this age.

Adolescent↗
PubMed1994

Effect of building ventilation design on environment and performance of turkeys.

Environmental variables in 10 commercial turkey confinement buildings, representing 2 natural ventilation designs, were measured during summer and the following winter. Sliding doors spaced at intervals along the walls of 5 of the buildings provided about 35% opening, and continuous wall curtains provided 60 to 80% opening in the other 5 buildings. Environmental variables assessed included airspeed; temperature; relative humidity; gases; particle number, size, and mass per cubic meter of air; and colonies of bacteria, yeasts, and other fungi per cubic meter of air. Colonies of yeasts and other fungi were quantitated in feed and litter. For most of the variables evaluated, significant differences were not attributable to building ventilation design; however, in winter, the total mass of particulate matter per cubic meter of air was higher in the curtain-type houses, compared with sliding door-type houses. Ammonia concentration in the air of sliding door-type houses progressively increased during summer and winter sampling periods. A significant effect of building ventilation design on turkey performance was not detected when using mortality, average daily gain, feed conversion, condemnations at slaughter, or average individual bird weight as measures of production.

Air↗
PubMed2000

Building sickness syndrome in healthy and unhealthy buildings: an epidemiological and environmental assessment with cluster analysis.

OBJECTIVES: Building sickness syndrome remains poorly understood. Aetiological factors range from temperature, humidity, and air movement to internal pollutants, dust, lighting, and noise factors. The reported study was designed to investigate whether relations between symptoms of sick building syndrome and measured environmental factors existed within state of the art air conditioned buildings with satisfactory maintenance programmes expected to provide a healthy indoor environment. METHODS: Five buildings were studied, three of which were state of the art air conditioned buildings. One was a naturally ventilated control building and one a previously studied and known sick building. A questionnaire was administered to the study population to measure the presence of building related symptoms. This was followed by a detailed environmental survey in identified high and low symptom areas within each building. These areas were compared for their environmental performance. RESULTS: Two of the air conditioned buildings performed well with a low prevalence of building related symptoms. Both of these buildings out performed the naturally ventilated building for the low number of symptoms and in many of the environmental measures. One building (C), expected to perform well from a design viewpoint had a high prevalence of symptoms and behaved in a similar manner to the known sick building. Environmental indices associated with symptoms varied from building to building. Consistent associations between environmental variables were found for particulates (itchy eyes, dry throat, headache, and lethargy) across all buildings. There were persisting relations between particulates and symptoms (headache, lethargy, and dry skin) even in the building with the lowest level of symptoms and of measured airborne particulates (building B). There were also consistent findings for noise variables with low frequency noise being directly associated with symptoms (stuffy nose, itchy eyes, and dry skin) and higher frequency noise being relatively protective across all buildings. CONCLUSIONS: This is the first epidemiological study of expected state of the art, air conditioned buildings. These buildings can produce an internal environment better than that of naturally ventilated buildings for both reported symptoms and environmental variables. The factors associated with symptoms varied widely across the different buildings studied although consistent associations for symptoms were found with increased exposure to particulates and low frequency noise.

Adult↗
PubMed2002

Use of remote sensing and a geographical information system in a national helminth control programme in Chad.

OBJECTIVE: To design and implement a rapid and valid epidemiological assessment of helminths among schoolchildren in Chad using ecological zones defined by remote sensing satellite sensor data and to investigate the environmental limits of helminth distribution. METHODS: Remote sensing proxy environmental data were used to define seven ecological zones in Chad. These were combined with population data in a geographical information system (GIS) in order to define a sampling protocol. On this basis, 20 schools were surveyed. Multilevel analysis, by means of generalized estimating equations to account for clustering at the school level, was used to investigate the relationship between infection patterns and key environmental variables. FINDINGS: In a sample of 1023 schoolchildren, 22.5% were infected with Schistosoma haematobium and 32.7% with hookworm. None were infected with Ascaris lumbricoides or Trichuris trichiura. The prevalence of S. haematobium and hookworm showed marked geographical heterogeneity and the observed patterns showed a close association with the defined ecological zones and significant relationships with environmental variables. These results contribute towards defining the thermal limits of geohelminth species. Predictions of infection prevalence were made for each school surveyed with the aid of models previously developed for Cameroon. These models correctly predicted that A. lumbricoides and T. trichiura would not occur in Chad but the predictions for S. haematobium were less reliable at the school level. CONCLUSION: GIS and remote sensing can play an important part in the rapid planning of helminth control programmes where little information on disease burden is available. Remote sensing prediction models can indicate patterns of geohelminth infection but can only identify potential areas of high risk for S. haematobium.

Adolescent↗
PubMed2006

Fluctuation in the physical environment as a mechanism for reinforcing evolutionary transitions.

We hypothesize a mechanism for reinforcing transitions between levels of selection, involving physiological homeostasis and amplification of variation in the physical environment. Groups experience a stronger selection pressure than individuals for homeostasis with respect to reproductively limiting variables, because their greater longevity exposes them more often to suboptimal physical conditions, and greater physical size means they encompass a larger fraction of any resource/nutrient gradient. Groups achieve homeostasis by differentiation into microcosms with specialist functions, e.g. cell types. Such differentiation is more limited in individuals due to their smaller size and shorter lifespan. Hence tolerance of fluctuation in certain physical variables is proposed to be weaker in individuals than in groups. We show that a trait providing increased tolerance (alpha) to fluctuation (V-V(opt)) in a limiting abiotic variable (V), at relative fitness cost (C), can increase from rarity if the condition alpha.mid R:V-V(opt)|>C is met. Groups also sequester larger absolute quantities of resource than individuals, and group death is less frequent, hence the population dynamics of groups cause resource/nutrient availability to fluctuate with greater amplitude than that of individuals. Increasing the amplitude of fluctuation in a reproductively limiting environmental variable is proposed as a mechanism by which a group can limit reproduction of parasitic "cheat" individuals. Enhancing physical fluctuation is frequency dependent, hence only an increase in tolerance to fluctuation can explain the group's increase from rarity. However, once groups reach intermediate frequencies, a positive feedback process can be initiated in which a differentiated group enhances physical fluctuation beyond the tolerance of any "cheat", and in so doing enhances the selection pressure it experiences for homeostasis. This may help explain the persistence of transitions in individuality, and the coincidence of some such transitions with periods of change and oscillation in global scale environmental variables.

Altruism↗
PubMed2005

Built environment and behavior: spatial sampling using parcel data.

PURPOSE: The quality and economy of inferential research rely heavily on the sampling method. This paper addresses a methodological challenge in environment-behavior research: sampling respondents in relation to their built environmental characteristics. METHODS: A discussion of issues related to traditional neighborhood-based sampling serves to introduce a new spatial sampling strategy. Spatial sampling consists of defining conceptual population of interest, constructing spatial sample frame using parcel-level environmental data in GIS, examining the sample frame, determining the sampling design and size, and drawing the samples. An application of this method is illustrated using a recent study examining environmental correlates of walking and biking. RESULTS: Spatial sampling with parcel-level data ensures sufficient variations in and proper distributions of the environmental variables of interest, while controlling for the conditions of no interest. The use of the individual as unit of analysis offers an economic, generalizable, and easily interpretable approach to environment-behavior research, and discourages the potentially erroneous a priori definition of neighborhoods and aggregation problems. CONCLUSIONS: With its capacity to consider a broad range of detailed environmental variables, spatial sampling contributes to finding new or stronger environment-behavior associations and to the growing number of studies using the social ecologic model.

Bicycling↗
PubMed1995

Environmental risk factors for Lyme disease identified with geographic information systems.

OBJECTIVES: A geographic information system was used to identify and locate residential environmental risk factors for Lyme disease. METHODS: Data were obtained for 53 environmental variables at the residences of Lyme disease case patients in Baltimore County from 1989 through 1990 and compared with data for randomly selected addresses. A risk model was generated combining the geographic information system with logistic regression analysis. The model was validated by comparing the distribution of cases in 1991 with another group of randomly selected addresses. RESULTS: In crude analyses, 11 environmental variables were associated with Lyme disease. In adjusted analyses, residence in forested areas (odds ratio [OR] = 3.7, 95% confidence interval [CI] = 1.2, 11.8), on specific soils (OR = 2.1, 95% CI = 1.0, 4.4), and in two regions of the county (OR = 3.5, 95% CI = 1.6, 7.4) (OR = 2.8, 95% CI = 1.0, 7.7) was associated with elevated risk of getting Lyme disease. Residence in highly developed regions was protective (OR = 0.3, 95% CI = 0.1, 1.0). The risk of Lyme disease in 1991 increased with risk categories defined from the 1989 through 1990 data. CONCLUSIONS: Combining a geographic information system with epidemiologic methods can be used to rapidly identify risk factors of zoonotic disease over large areas.

Environmental Exposure↗
PubMed1995

Modelling stomatal responses of spring wheat (Triticum aestivum L. cv. Turbo) to ozone and different levels of water supply.

Spring wheat (Triticum aestivum L. cv. Turbo) was exposed to different levels of ozone and water supply in open-top chambers in 1991. Air was charcoal filtered (CF), non-filtered (NF) and CF plus proportional addition of ambient or twice ambient ozone (CF1, CF2). Seasonal means of O(3), taken over 24 h, were 2.3, 20.6, 17.3, and 34.5 nl litre(-1) for CF, NF, CF1 and CF2 treatments, respectively. A split-plot design was used to obtain two levels of water supply: one-half of the pots was irrigated sufficiently not to show any symptoms of drought stress; the others were exposed to low water supply and received 50% of these amounts. Using a steady-state porometer approximately 800 measurements of stomatal conductance (g(s)) were made on flag leaves from 68 to 106 days after sowing. The measurements yielded only small differences of maximum conductance between the two levels of water supply. Therefore, low water supply did not protect wheat plants against ozone injury via reduced stomatal uptake in this experiment. To describe the effects of environmental variables on the stomatal behaviour, boundary-line analysis and non-linear regression analysis were used. Besides microclimatic parameters, the ozone dose of flag leaves was introduced as an independent variable affecting stomatal aperture. A well-defined boundary line for ozone dose was found, suggesting that increasing ozone dose caused stomatal closure in wheat flag leaves. But at high ozone doses, co-acting senescence seems also responsible for the decrease in stomatal conductance. A multiplicative boundary-line model was used to predict stomatal conductance from combinations of environmental variables. In the test carried out with the measurements of stomatal conductance, the model accounted only for 40% of the variation of g(s). Generalized stomatal response patterns of the herbaceous growth form, the dependence of the variables' age and ozone dose and the lack of an important factor influencing stomatal response (water status of the plant) in the model, are suggested as explanations of the poor results of the test.

Journal Article↗
PubMed1997

Density of larval Culicoides belkini (Diptera:Ceratopogonidae) in relation to physicochemical variables in different habitats.

Immature density and population size of the biting midge Culicoides belkini (Wirth & Arnaud) were estimated for habitats on Moorea Island, French Polynesia, by means of random, 2- and 3-stage sampling designs. Samples were taken in March 1993 from 5 strata of a large larval habitat: a sandy-mud surface of approximately 5,000 m2 (stratum 1) in which approximately 12,000 land crab burrows (stratum 2) were counted, a small pond surrounded by approximately 300 m2 of muddy bank (stratum 3), and a high organic muddy area (Kopara) of approximately 1,200 m2 (stratum 4) with approximately 3,500 crab burrows (stratum 5). Larval density was usually higher in the mud of crab burrows, especially those in the Kopara stratum. Larval density was significantly lower in the sediment of the sandy area as compared with pond banks or Kopara surface. The sampling designs and techniques were logistically adequate, statistically relevant, and were recommended for future studies on C. belkini larval density. Larval habitats were characterized by means of multivariate analysis. Comparison of larval densities with selected environmental variables indicated that larvae density was higher in wet sediments with high levels of organic matter (approximately 8% of dry weight of sediment) and low salinity (approximately 0.5-1.5% NaCl equivalents). These variables were considered significant if larval control by means of habitat modification has to be achieved. Nevertheless, C. belkini can tolerate a broad spectrum of variation in the other environmental variables measured and breed in a variety of ecological situations. Therefore, it has a high potential for colonizing new habitats.

Animals↗
PubMed1999

A preliminary statistical examination of the effects of uncertainty and variability on environmental regulatory criteria for ozone.

Basing the quantitative expression of environmental regulatory standards and associated compliance criteria on statistical principles has recently received attention in Europe, most visibly in a study by the UK Royal Commission on Environmental Pollution. These issues are timely for consideration in the USA, where a recent periodic review of National Ambient Air Quality Standards (NAAQS) has led to revision of the regulatory standards for ambient ozone and particulate matter. Salient statistical issues include accounting for errors of the first and second kind due to sampling and measurement error. These issues appear routine statistically and also may seem absent from regulations, but neither is necessarily the case. This paper is directed towards developing a methodology for examining the problem of dealing with uncertainty and variation in environmental regulations and compliance criteria. Our approach is illustrated through statistical analysis of the (old) 1 hour and the (new) 8 hour standards for ambient ozone, based on intensive monitoring in California's San Joaquin Valley during summer 1990 performed under the SARMAP Project. This paper presents preliminary findings based on quantifying measurement error or precision in terms of small-scale spatial and temporal variability, laying the groundwork for future work.

Air Pollutants↗
PubMed2002

Documenting a significant relationship between macroevolutionary origination rates and Phanerozoic pCO2 levels.

We show that the rates of diversification of the marine fauna and the levels of atmospheric CO(2) have been closely correlated for the past 545 million years. These results, using two of the fundamental databases of the Earth's biota and the Earth's atmospheric composition, respectively, are highly statistically significant (P < 0.001). The strength of the correlation suggests that one or more environmental variables controlling CO(2) levels have had a profound impact on evolution throughout the history of metazoan life. Comparing our work with highly significant correlations described by D. H. Rothman [Rothman, D. H. (2001) Proc. Natl. Acad. Sci. USA 98, 4305-4310] between total biological diversity and a measure of stable carbon isotope fractionation, we find that the rates of diversification rather than total diversification correlate with environmental variables, and that the rate of diversification follows the record of CO(2) projected by R. A. Berner and Z. Kothavala [Berner, R. A. & Kothavala, Z. (2001) Am. J. Sci. 301, 182-204] more closely than that predicted by Rothman.

Biological Evolution↗
PubMed2000

Suitability of log-linear models to evaluate the microbiological quality of baby clams (Chamelea gallina L.) harvested in the Adriatic Sea.

The presence of fecal coliforms or Escherichia coli in baby clams (Chamelea gallina L.) is considered an indicator related to their safety because they can be correlated with the presence of pathogenic bacteria. For this reason the Italian regulation has defined limits for these microorganisms. The presence of these microbial indicators is dependent on various environmental variables. In this work all the variables considered are categorical and, consequently, the traditional approach of predictive microbiology was not applicable. The data were summarized by means of a cross-tabulation and analyzed using the log-linear model technique. This statistical technique is widely used in social and economic studies but only partially developed in food microbiology. The suitability of the log-linear model to analyse microbiological data in relation to environmental variables was evaluated. In particular, the microbiological quality of baby clams harvested in five different areas of the Adriatic Sea coast in Emilia Romagna (Italy) was considered. The influence of the season and geographical origin on microbiological standards was assessed. A logit model was developed to predict the frequencies, depending on geographical origin and season, of samples with concentrations of the indicator organisms below or above the legal standards provided by Italian regulation.

Animals↗
PubMed2004

Trace metal availability and effects on benthic community structure in floodplain lakes.

Effects of contaminants on communities are difficult to assess and poorly understood. We analyzed in situ effects of trace metals and common environmental variables on benthic macroinvertebrate communities in floodplain lakes. Alternative measures of trace metal availability were evaluated, including total metals, metals normalized on organic carbon (OC) or clay, simultaneously extracted metals (SEM), combinations of SEM and acid-volatile sulfide (AVS), and metals accumulated by detritivore invertebrates (Oligochaeta). Accumulated metal concentrations correlated positively with sediment trace metals and negatively with surface water dissolved OC. Sixty-eight percent of the variation in benthic community composition was explained by a combination of 11 environmental variables, including sediment, water, and morphological characteristics with trace metals. Metals explained 2 to 6% of the community composition when SEM-AVS or individual SEM concentrations were regarded. In contrast, total, normalized, and accumulated metals were not significantly linked to community composition. We conclude that examination of SEM or SEM - AVS concentrations is useful for risk assessment of trace metals on the community level.

Aluminum Silicates↗
PubMed2002

The nature of robustness in development.

A trait is robust to a genetic or environmental variable if its variation is weakly correlated with variation in that variable. The source of robustness lies in the fact that the developmental processes that give rise to complex traits are nonlinear. A consequence of this nonlinearity is that not all genes are equally correlated with the trait whose ontogeny they control. Here we explore how developmental mechanisms determine and alter the correlation structure between genes and the traits that they control. A formula is developed by which the correlation of a gene or environmental variable with a trait can be calculated if the mechanism that gives rise to the trait is known. The nature of robustness and the ways in which robustness can evolve are discussed in the context of the problems that arise in the analysis of inherently nonlinear systems.

Alleles↗
PubMed2004

Constitutional and environmental risk factors for cutaneous melanoma in an Italian population. A case-control study.

The aim of this study was to determine the relative risk for cutaneous melanoma associated with phenotypic and environmental variables in a population in central Italy and to assess how the combination of the different risk factors contributes to the overall risk for melanoma. We performed a case-control study of 100 patients with sporadic cutaneous melanoma and 200 controls matched for sex, age, ethnicity and residential area. Individuals were interviewed concerning pigmentary traits and sun exposure, and underwent a total body skin examination. Logistic regression models were used to evaluate the association between cutaneous melanoma and constitutional and environmental variables. The strongest risk factors were prolonged recreational sun exposure (odds ratio [OR] 5.010, 95% confidence interval [CI] 2.110-11.891), the presence of clinically atypical naevi (OR 4.916, 95% CI 2.496-9.995) and the presence of >50 common melanocytic naevi (OR 4.684, 95% CI 2.442-9.231). In addition, occupational sun exposure (OR 2.573, 95% CI 1.399-4.732), light brown hair (OR 2.336, 95% CI 1.328-4.138), high density of solar lentigos and/or actinic keratoses (OR 1.824, 95% CI 1.0-3.510) and type II, fair skin (OR 1.815, 95% CI 1.031-3.193) and blue eyes (OR 1.757, 95% CI 1.0-3.477) were each significantly associated with cutaneous melanoma risk. The combination of individual strong risk factors was associated with up to a 46-fold increase in the risk for cutaneous melanoma. Selected pigmentary traits, sun exposure and melanocytic naevi, individually and in combination, are important risk factors for cutaneous melanoma in an Italian population.

Adolescent↗
PubMed1980

Relationship of size to resident and staff behavior in small community residences.

The daily behavior of 240 mentally retarded residents and 75 staff members was analyzed in relation to facility size (ranging from 6 to 20 residents) and other environmental variables. For the 20 group homes studied, staff behavior was remarkably homogeneous and generally unrelated to facility characteristics. In contrast, resident behavior differed significantly across group homes. In larger facilities, residents engaged in more social behavior, particularly with peers, and were more likely to have intense, reciprocal friendships than were those in smaller facilities. Despite more enriched staff:resident ratios in the smaller homes, amount of staff-resident interaction was not related to size. Overall, other environmental variables--such as location and social grouping--were more closely associated with observed behavior patterns than was size.

Activities of Daily Living↗
PubMed2001

Reproductive pair correlations and the clustering of organisms.

Clustering of organisms can be a consequence of social behaviour, or of the response of individuals to chemical and physical cues. Environmental variability can also cause clustering: for example, marine turbulence transports plankton and produces chlorophyll concentration patterns in the upper ocean. Even in a homogeneous environment, nonlinear interactions between species can result in spontaneous pattern formation. Here we show that a population of independent, random-walking organisms ('brownian bugs'), reproducing by binary division and dying at constant rates, spontaneously aggregates. Using an individual-based model, we show that clusters form out of spatially homogeneous initial conditions without environmental variability, predator-prey interactions, kinesis or taxis. The clustering mechanism is reproductively driven-birth must always be adjacent to a living organism. This clustering can overwhelm diffusion and create non-poissonian correlations between pairs (parent and offspring) or organisms, leading to the emergence of patterns.

Models, Biological↗