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PubMed2002

Identifying barriers to the use of research faced by public health physicians in Norway and developing an intervention to reduce them.

OBJECTIVES: To explore why public health physicians seldom use research-based information and to develop an intervention to remedy this on the basis of this study, other research literature and suitable theories of information-seeking and professional behaviour change. METHODS: A qualitative study was conducted using focus groups, observation of individuals and interviews. The setting was Norwegian public health practice; 52 public health physicians from all over Norway participated in the study. RESULTS: We identified several barriers to the use of scientific literature that could be categorised as: psychological variables; environmental variables; and source characteristics. We developed an intervention that attempts to address these barriers, informed by previous research on the effectiveness of interventions to change professional practice and incorporating elements from social cognitive theories and the theory of innovation diffusion. CONCLUSIONS: The Norweigian public health physician works in an isolated environment which does not facilitate searching or obtaining scientific information, which does not ask for this information and far less encourages its use as a basis for decision-making. An intervention tailored to reduce some of the barriers to research use may lead to more frequent and extensive use of such information in public health decision-making.

Anecdotes as Topic↗
PubMedDate not supplied

Environmental mapping based on spatial variability.

Environmental maps show the probable environmental states of different types of land use or development of landscape in a geographic context. Remotely sensed data are particularly efficient for environmental mapping in order to outline major environmental types. Multiple schemes of image classification used in environmental mapping are either traditionally statistical or heuristic. While the former methods do not take account of spatial variability in space and aerial data, the latter ones does not lend themselves to optimal solutions we present. Novel probabilistic models of piecewise-homogeneous images are used in environmental mapping to segment real images. The models consider both an image and a land cover map. Such a pair constitutes an example of a Markov random field specified by a joint Gibbs probability distribution of images and maps. Parameters of the model are estimated by using a stochastic approximation technique. Its convergence to the desired values is studied experimentally. Addition of spatial attributes appears to be necessary in most areas where the differences in spatial data between regions in the image occur. Experiments in generating the pairs of images and environmental maps and in segmenting the simulated as well as real images are discussed.

Environment↗
PubMed2001

Acute exposure to environmental tobacco smoke and heart rate variability.

Environmental tobacco smoke (ETS) has been associated with cardiovascular mortality. Pathophysiologic pathways leading from ETS exposure to cardiopulmonary disease are still being explored. Reduced cardiac autonomic function, as measured by heart rate variability (HRV), has been associated with cardiac vulnerability and may represent an important pathophysiologic mechanism linking ETS and risk of cardiac mortality. In this study we evaluated acute ETS exposure in a commercial airport with changes in HRV in 16 adult nonsmokers. We conducted ambulatory electrocardiographic (ECG) monitoring for 8-hr periods while participants alternated 2 hr in nonsmoking and smoking areas. Nicotine and respirable suspended particle concentrations and participants' blood oxygen saturation were also monitored. We calculated time and frequency domain measures of HRV for periods in and out of the smoking area, and we evaluated associations with ETS using comparative statistics and regression modeling. ETS exposure was negatively associated with all measures of HRV. During exposure periods, we observed an average decrement of approximately 12% in the standard deviation of all normal-to-normal heart beat intervals (an estimate of overall HRV). ETS exposures were not associated with mean heart rate or blood oxygen saturation. Altered cardiac autonomic function, assessed by decrements in HRV, is associated with acute exposure to ETS and may be part of the pathophysiologic mechanisms linking ETS exposure and increased cardiac vulnerability.

Adult↗
PubMed2006

Linkages between nutrients and assemblages of macroinvertebrates and fish in wadeable streams: implication to nutrient criteria development.

We sampled 240 wadeable streams across Wisconsin for different forms of phosphorus and nitrogen, and assemblages of macroinvertebrates and fish to (1) examine how macroinvertebrate and fish measures correlated with the nutrients; (2) quantify relationships between key biological measures and nutrient forms to identify potential threshold levels of nutrients to support nutrient criteria development; and (3) evaluate the importance of nutrients in influencing biological assemblages relative to other physicochemical factors at different spatial scales. Twenty-three of the 35 fish and 18 of the 26 macroinvertebrate measures significantly correlated (P < 0.05) with at least one nutrient measure. Percentages of carnivorous, intolerant, and omnivorous fishes, index of biotic integrity, and salmonid abundance were fish measures correlated with the most nutrient measures and had the highest correlation coefficients. Percentages of Ephemeroptera-Plecoptera-Trichoptera individuals and taxa, Hilsenhoff biotic index, and mean tolerance value were macroinvertebrate measures that most strongly correlated with the most nutrient measures. Selected biological measures showed clear trends toward degradation as concentrations of phosphorus and nitrogen increased, and some measures showed clear thresholds where biological measures changed drastically with small changes in nutrient concentrations. Our selected environmental factors explained 54% of the variation in the fish assemblages. Of this explained variance, 46% was attributed to catchment and instream habitat, 15% to nutrients, 3% to other water quality measures, and 36% to the interactions among all the environmental variables. Selected environmental factors explained 53% of the variation in macroinvertebrate assemblages. Of this explained variance, 42% was attributed to catchment and instream habitat, 22% to nutrients, 5% to other water quality measures, and 32% to the interactions among all the environmental variables.

Animals↗
PubMed2003

Impaired cardiac autonomic functions in patients with environmental asbestos exposure: a study of time domain heart rate variability.

Environmental asbestos exposure is related to diffuse pleural disease (thickening and calcification) and restrictive pulmonary disease. To assess cardiac autonomic system, we investigated the time domain heart rate variability (HRV) by Holter monitoring and their correlation with pulmonary function tests in patients with pleural disease caused by environmental asbestos exposure. We studied 45 patients (26 men, 19 women, aged 62.67 +/- 10.1 years) and 35 healthy patients who had similar sex and age profile to the patients (24 men, 11 women, aged 59.31 +/- 8.4 years). The asbestosis group was divided into 3 subgroups according to the severity of forced vital capacity (FVC) severe (group 1) (n = 12): FVC less than 50% of expected, moderate (group 2) (n = 16): FVC 64%-51% of expected and mild (group 3) (n = 17): FVC 65%-80% of expected. HRV parameters were significantly different among all groups (P<.0001). Comparing the 4 groups (subgroups and control group), group 1 had the lowest mean HRV values and controls had the highest mean HRV values (P<.0001). Severity of autonomic dysfunction was correlated with the severity of FVC and arterial oxygen pressure. Right ventricular end-diastolic internal diameter (RVEDID) and right ventricular end-systolic internal diameter (RVESID) values were significantly increased in patients (P <.0001, P < 0.0001, respectively). Pulmonary acceleration time (AcT) values were shorter in all patient groups than control group (P <.0001). It was shortest in group 1. Group 2 and 3 had shorter AcT values than control group. HRV parameters were correlated positively with AcT values and negatively with RVEDID and RVESID values. In conclusion, patients with restrictive pulmonary disease due to environmental asbestos exposure had autonomic dysfunction, which was correlated with the severity of restriction. This was thought to be the result of chronic hypoxia, pulmonary hypertension, and right ventricular enlargement.

Analysis of Variance↗
PubMed2006

Predictors of suicidal ideation among high school students by gender in South Korea.

The purpose of this study was to examine the evidence to determine if there are gender differences in suicidal ideation of adolescents. This study examined the main effect of risk factors from 5 domains and protective factors from 1 domain in relation to suicidal ideation by gender and identified the most important predictors of suicidal ideation for males (N = 654) and females (N = 658). This study was a cross-sectional survey, and data were collected through self-report questionnaires. In the univariate analysis, especially, risk factors from behavioral variables and psychosocial-environmental variables appeared to be gender skewed. For males, all behavioral variables were predictive of suicidal ideation. For the females, unlike the males, Wang-tta or victim of bullying behavior and sexual orientation as behavioral variables were predictive of suicidal ideation. For males, parental divorce and parental alcohol abuse as psychosocial-environmental variables were predictive of suicidal ideation. For the females, again unlike for the males, all the psychosocial-environmental variables were not predictive of suicidal ideation. The most important predictors of suicidal ideation for males as a result of the multivariate analysis were history of suicidal attempt, depression, hostility, smoking, parental alcohol abuse, communication with friends, and self-esteem. The most important predictors of suicidal ideation for females as a result of the multivariate analysis were depression, hostility, sexual orientation, and self-esteem. These results would indicate that an effective suicide screening and prevention program for adolescents should consider gender differences.

Adolescent↗
PubMed1985

Changes in drug sensitivity following acute and chronic exercise.

A number of factors are known to influence drug sensitivity. These include biological variables such as genetics, age, endocrine status and gender, as well as environmental variables such as operant schedules, ambient temperature and sleep deprivation. Additional factors function as either biological or environmental variables in different situations. For example, chronic drug administration can produce tolerance and cross tolerance and function as a biological variable. Acute administration of the same compound can function as an environmental variable. The present study examined exercise as both a biological and an environmental variable influencing drug sensitivity. Chronic exercise leads to relatively long term changes in physical fitness level, and functions as a biological variable. Fitness level did not influence drug sensitivity when physically conditioned animals and non-exercised control subjects were compared under rested conditions. Mild acute exercise, an environmental variable, increased sensitivity to muscarinic antagonists in the control subjects but not in the exercise trained animals. These results indicate that exercise state should be considered as an environmental variable capable of influencing drug response and that biological fitness level modifies this effect.

Animals↗
PubMed2003

Correlates of recreational and transportation physical activity among adults in a New England community.

BACKGROUND: Promotion of transportation-related physical activity is consistent with current national recommendations. However, few studies have simultaneously examined correlates of recreational and transportation physical activity. METHODS: Surveys were mailed to 1002 adults residing in a Massachusetts suburb. The survey included measures of self-reported recreational and transportation-related physical activity and demographic, cognitive, interpersonal, and environmental variables potentially correlated with activity. Multiple linear regression was used to examine the associations between environmental variables and the two outcomes. RESULTS: Respondents (n = 413) who averaged 51.2 +/- 16.8 years of age reported 132.3 +/- 140.5 min/week recreational physical activity and 142.1 +/- 180.9 min/week transportation activity. Sidewalks (P = 0.02) and traffic (P = 0.01) were each associated with higher levels of recreational physical activity in unadjusted analyses, but in models that controlled for age, self-efficacy for physical activity and family social support for physical activity, these environmental variables were nonsignificant. Three perceived environmental variables (enjoyable scenery, sidewalks, traffic) and one objective environmental variable (distance from home to a community rail-trail) each showed associations (P </= 0.05) with transportation-related physical activity in models that controlled for age and self-efficacy. CONCLUSIONS: Neighborhood physical environmental variables were associated with transportation physical activity, but not with recreational physical activity. Further research is needed to identify shared and unique correlates of recreational and transportation physical activity in urban, suburban, and rural settings.

Activities of Daily Living↗
PubMed1988

Fitness and fertility among Kalahari !Kung.

In this paper we develop a model that examines fertility and childhood mortality patterns and their relationship to environmental variables. Interactions among environmental variables can account for different fertility patterns and different mixes of these variables can produce similar patterns of fertility. Our model attempts to quantify the idea that there is a trade-off between producing a few children likely to survive to reproductive age and producing a greater number of children with lower chances for survival. The optimum mix of these strategies depends on environmental characteristics. We use the model to make predictions about fertility and mortality patterns among two Bushmen populations of southern Africa--the Ghanzi and Ngamiland !Kung--using data collected by Harpending in 1967-1968. The results do not support explanations of the low fertilities observed among !Kung Bushmen women, in whom it is thought that fitness is maximized by limiting fertility, and show no relationship between mortality and family size in either !Kung population. Instead, the number of offspring reaching reproductive age in both populations increases as their completed family size increases. We examine the effects of sex, birth order, and paternal investment on mortality. No sex ratio differences and no differences in mortality by sex or birth order are present. Infant mortality among women who married more than once is significantly higher than among women who married once, suggesting that paternal care has a significant effect.

Adult↗
PubMed2005

Spatial variation in insect community and species responses to habitat loss and plant community composition.

Several experimental studies have examined species responses to manipulations of habitat area and spatial arrangement, but plant composition and spatial variation in species distributions also affect animal responses to habitat alteration. We used an experimental approach to study the combined effects of habitat area, edge, and plant community composition on the spatial structure of insect species richness and composition. The abundance of three guilds (herbivores, predators and parasitoids) and individual species were also analyzed. Habitat patches were created that differed in area and edge by selectively mowing portions of 15 mx15 m plots in a 1.7-ha old field. Spatial and environmental variables were used to predict insect responses in separate multiple regression and ordination models. The variation in species responses due to spatial and environmental variables was then partitioned by combining these variables into an overall regression or ordination. Spatial and environmental variables contributed similar percentages to the total variance in insect species richness, abundance or composition. No significant effects of habitat area were observed in any response variable. Herbivore abundance showed positive responses to legume or grass cover, as well as spatial variation that was unrelated to environmental variables. Predators and parasitoids had greater effects of plant species richness and habitat edge, and less unexplained spatial variation. Individual species differed in their responses to plant variables, depending on host specialization or intraspecific aggregation. Our study highlights the importance of plant community composition and spatial variation apart from environmental variables. Spatial variation stems both from species responses to environmental features as well as species differences in habitat specialization and intraspecific aggregation.

Animals↗
PubMed2004

[Environmental impact of ecological changes in a subtropical area].

Infectious, clinical-surgical and environmental variables were studied in Ituzaingó and Posadas (Argentina) and differences were analyzed from 1994 to 2000, which corresponds to the building of the binational dam Yacyretá (Argentina-Paraguay) and to the resulting reservoir. The chosen infectious variables were diarrhea and respiratory infections and the clinical-surgical variables were cardiovascular diseases and polytraumas. Environmental variables were also investigated. Taking as a baseline the values corresponding to the year 1994, diarrhea in Ituzaingó, increased 6.5% during 1995 and 78.3% in 1996 returned to 1994 values. Posadas showed a rising tendency throughout the period investigated. In Ituzaingó, respiratory infectious rose 143% in 1995, and later returned to 1994 values. In Posadas they increased each year. Cardiovascular diseases reached 97.6% in Ituzaingó during 1995; lowered slightly in 1996 and reached 127% in the year 2000. The impact of the environmental variables was higher in Ituzaingó than Posadas. The negative impact of temperature related with the increased frequency of disease in Ituzaingó is more related to maximum temperature than with changes in humidity.

Argentina↗
PubMed2001

Metabolic rate and environmental productivity: well-provisioned animals evolved to run and idle fast.

Even among vertebrate species of the same body mass and higher-level taxonomic group, metabolic rates exhibit substantial differences, for which diverse explanatory factors-such as dietary energy content, latitude, altitude, temperature, and rainfall-have been postulated. A unifying underlying factor could be food availability, in turn controlled by net primary productivity (NPP) of the animal's natural environment. We tested this possibility by studying five North American species of Peromyscus mice, all of them similar in diet (generalist omnivores) and in gut morphology but differing by factors of up to 13 in NPP of their habitat of origin. We maintained breeding colonies of all five species in the laboratory under identical conditions and consuming identical diets. Basal metabolic rate (BMR) and daily ad libitum food intake both increased with NPP, which explained 88% and 90% of their variances, respectively. High-metabolism mouse species from high-NPP environments were behaviorally more active than were low-metabolism species from low-NPP environments. Intestinal glucose uptake capacity also increased with NPP (and with BMR and food intake), because species of high-NPP environments had larger small intestines and higher uptake rates. For metabolic rates of our five species, the driving environmental variable is environmental productivity itself (and hence food availability), rather than temporal variability of productivity. Thus, species that have evolved in the presence of abundant food run their metabolism "fast," both while active and while idling, as compared with species of less productive environments, even when all species are given access to unlimited food.

Animals↗
PubMed1974

Isozyme allelic frequencies related to selection and gene-flow hypotheses.

Significant correlations between allelic frequencies and environmental variables in a number of insect species have been demonstrated by multivariate techniques. Since many environmental variables show a strong relationship to geographic location and since gene flow between populations can also produce patterns of gene frequencies which are related to the geographic location, both selection and gene-flow hypotheses are consistent with the observed correlations. The genetic variables can be corrected for geographic location and so for linear gene-flow patterns. If, after correction, the genetic variables still show significant correlations with similarly corrected environmental variables, then these correlations are consistent with hypotheses of selection but not of gene flow. The data of Johnson and Schaffer (1973) have been reanalyzed using the method of canonical correlation after correction for geographical location by means of multiple regression. Five of the nine loci studied exhibit significant canonical correlations. These results, under the assumption of linear gene flow, support hypotheses of selective action of environmental variables in the genotype-environment relationships observed.

Alleles↗
PubMed2005

The Watcombe housing study: the short-term effect of improving housing conditions on the indoor environment.

A three-year study (1999-2001) was initiated in the UK to assess the effect of improving housing conditions in 3-4 bedroom, single-family unit, social rented sector houses on the health of the occupants. The houses were randomised into two groups. Phase I houses received extensive upgrading including wet central heating, on demand ventilation, double-glazed doors, cavity wall and roof/loft insulation. An identical intervention for Phase II houses was delayed for one year. As part of this randomised waiting list study, discrete measurements were made of indoor environmental variables in each house, to assess the short-term effects of improving housing conditions on the indoor environment. Variables representative of indoor environmental conditions were measured in the living room, bedroom and outdoors in each of the three years of the study. In 2000, there was a significant difference between the changes from 1999 to 2000 between Phase I (upgraded) and II (not then upgraded) houses for bedroom temperatures (p=0.002). Changes in wall surface dampness and wall dampness in Phase I houses were also significantly different to the change in Phase II houses in 2000 (p=0.001), but by 2001 the Phase I houses had reverted to the same dampness levels they had before upgrading. The housing upgrades increased bedroom temperatures in all houses. Other indoor environmental variables were not affected.

Air Pollutants↗
PubMed2004

Psychosocial variables in a cohort of students in grades 8 and 11: a comparison of current and never smokers.

BACKGROUND: Specific hypotheses regarding putative mechanisms by which stressful life events might be related to smoking initiation among adolescents have been tested cross-sectionally on a cohort of 1598 grade 6 students in Scarborough, Canada. The purpose of this study was to examine the utility of these cross-sectional models in accounting for current smoking as compared to never smoking when this cohort was in grades 8 and 11. METHODS: Current smoking was defined as reported regular or occasional smoking. Logistic regression and multiple regression models were tested separately for each gender and grade with variables entered in prespecified steps. RESULTS: Current smoking is more strongly related to psychosocial variables and environmental variables among older male adolescents as compared to younger ones. In older female adolescents, current smoking appears to be more strongly related to attitude variables and less strongly related to psychosocial variables than among younger female adolescents. There is some evidence that grade 11 males may use cigarettes as a coping strategy for depression. CONCLUSIONS: Male and female students differ in how stress and a range of psychosocial factors are interrelated with regards to current smoking and these relationships appear to change over time.

Adolescent↗
PubMed2004

Individual differences in executive attention predict self-regulation and adolescent psychosocial behaviors.

This study examined temperament, executive attention, parental monitoring and relationships, and involvement in pro- and antisocial behaviors in an ethnically diverse sample of adolescents. We sought to relate parent- and self-reported effortful control to performance on measures of executive attention and to better understand the relative contributions of individual-difference variables and environmental variables in predicting behaviors in adolescence. The results indicated a relationship between poor executive attention and mother-reported effortful control. Inclusion of individual-difference variables significantly increased prediction of problem-behavior scores, suggesting the importance of including such variables in studies of adolescent deviance.

Adolescent↗
PubMed1989

The use of the Morris Water Maze in the study of memory and learning.

Although the Morris Water Maze (MWM) was introduced only a few years ago, this technique has gained wide popularity, as the large number of publications in which it is employed, testifies. A review of the literature reveals that a wide variety of technical variables were used by the various research groups employing the MWM. This review describes the major changes in research variables, i.e., environmental variables, various manipulations, and the effects of diet or age on performance. The general principles of learning as demonstrated by the MWM are discussed.

Animals↗
PubMed1998

[Deteriorating vision in the elderly: double stress?].

BACKGROUND: Epidemiologic studies have provided clear evidence that the majority of people affected by severe visual impairment are adults above the age of 60 years. The goal of this psychological research was to analyze the emotional and behavioral consequences of age-related visual impairment in three steps: descriptive data concerned with subjective well-being, depression, everyday competence, and leisure as well as explanations of interindividual variability based on individual and environmental variables are presented (study I). Also, the impact of the time of onset (early versus late in life) is addressed (study II). Finally, the role of the living accomodation (institutional versus private household) was the main target of another study (study III). MATERIALS AND METHODS: Study I was based on 84 elderly adults who experienced an irreversible visual loss after age 55 years; a control group of unimpaired elderly adults is also included (mean age 75.8, range 59 to 92). In study II, 18 elderly adults who had been blind since their early childhood were compared to nine matched elderly adults who experienced blindness in their later life as well as nine matched unimpaired elderly adults (mean age 71.7, range 63 to 83). The data for study III came from 15 visually impaired institutional residents who were compared to 15 matched unimpaired residents and 15 matched visually impaired and 15 unimpaired older adults living in private households (mean age 87.0, range 78 to 93). All subjects underwent an intensive psychological measurement program. RESULTS: The findings of study I emphasize that age-related visual impairment is associated with lower subjective well-being, greater depression, reduced everyday competence, and lowered leisure activity level. A significant portion of interindividual variability in these outcomes can be explained by addressing individual variables (e.g., comorbidity) as well as environmental variables (e.g., quality of the dwelling unit). Study II data offer evidence that older adults suffering from blindness since their early childhood are better adapted than older adults who experienced blindness only in their later years. Study III shows that visually impaired institutional residents reveal deficits in everyday competence and social contacts as contrasted with their unimpaired counterparts, whereas no difference is observed in the domain of subjective well-being. CONCLUSIONS: All three studies point to the negative impact of age-related visual impairment on emotional and behavioral adaptation in later life. This highlights the need for a whole range of rehabilitative efforts, including psychosocial elements, which are described in the final part of this article.

Activities of Daily Living↗