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PubMed2003

Designing low-complexity electrical consumer products for ecological use.

This study examined the environmental impact of low-complexity electrical consumer products during their use in a domestic context. In the experimental scenario, 48 users were asked to use a kettle under different conditions. On-product information (OPI), task instruction, and kettle design were employed as independent variables in a mixed multi-factorial design to examine their effects on different parameters of ecological performance (e.g., water and electricity consumption). Measures of user variables (environmental concern, knowledge, domestic habits, environmental control beliefs) were also taken to examine their relationship with performance parameters. The results revealed main effects of ecological task instruction, OPI and (partly) kettle design on ecological user behaviour. Habits, environmental concern and control beliefs were found to be related to performance parameters whereas knowledge was not. The implications of the results for product design are discussed against the background of a strong prevalence of habits and low ecological user motivation.

Adult↗
PubMed2003

Scaling up: the next challenge in environmental microbiology.

Great strides have recently been made in identifying and characterizing the staggering diversity of microorganisms conducting primary and secondary production, nutrient transformation and mineralization processes that underlie ecosystem and regional biogeochemical, trophodynamic and ecological change. We are now faced with the challenge of assigning and coupling function to structure in highly complex and interactive microbial communities mediating such change. Previous and ongoing ecophysiological work has shown that microbial processes controlled by environmental variables and limiting resources are highly specific in terms of what, when, where and why they are active, not to mention how they impact ecosystem dynamics. As such, it is imperative that we assess the activities and roles of key microbial 'players' along the appropriate environmental scales and gradients catalysing ecological change. Here, we discuss conceptual and technical challenges for some key microbially mediated environmental processes, problems and extremes that require synthesizing our growing knowledge of microbial community structure with emerging knowledge of function in aquatic ecosystems. We emphasize the importance of assessing ecological change over a range of relevant time scales that vary from minutes to millennia and spatial scales that range from microscale aggregates to ocean basins.

Biodiversity↗
PubMed2001

Divergent evolution of dispersal in a heterogeneous landscape.

The evolution of dispersal is investigated in a landscape of many patches with fluctuating carrying capacities and spatial heterogeneity in temporal fluctuations. Although asynchronous temporal fluctuations select for dispersal, spatial heterogeneity in the distribution of fluctuating environmental variables selects against it. We find evolutionary branching in dispersal rate leading to the evolutionarily stable coexistence of a high- and a low-dispersal phenotype. We study how the opposing forces of selection for and against dispersal change with the relative size and the environmental qualities of the source and sink habitats. Our results suggest that the evolution of dispersal dimorphism could be a first step towards speciation and local adaptation.

Animals↗
PubMed2002

Populations and determinants of airborne fungi in large office buildings.

Bioaerosol concentrations in office environments and their roles in causing building-related symptoms have drawn much attention in recent years. Most bioaerosol studies have been cross-sectional. We conducted a longitudinal study to examine the characteristics of airborne fungal populations and correlations with other environmental parameters in office environments. We investigated four office buildings in Boston, Massachusetts, during 1 year beginning May 1997, recruiting 21 offices with open workstations. We conducted intensive bioaerosol sampling every 6 weeks resulting in 10 sets of measurement events at each workstation, and recorded relative humidity, temperature, and CO2 concentrations continuously. We used principal component analysis (PCA) to identify groups of culturable fungal taxa that covaried in air. Four major groupings (PCA factors) were derived where the fungal taxa in the same groupings shared similar ecological requirements. Total airborne fungal concentrations varied significantly by season (highest in summer, lowest in winter) and were positively correlated with relative humidity and negatively related to CO2 concentrations. The first and second PCA factors had similar correlations with environmental variables compared with total fungi. The results of this study provide essential information on the variability within airborne fungal populations in office environments over time. These data also provide background against which cross-sectional data can be compared to facilitate interpretation. More studies are needed to correlate airborne fungi and occupants' health, controlling for seasonal effects and other important environmental factors.

Air Pollution, Indoor↗
PubMed2006

[The basic health plan's impact on preventing cutaneous leishmaniasis in rural areas of Santander, Colombia].

OBJECTIVE: Measuring the impact of the Basic Colombian Health Plan for Preventing Cutaneous Leishmaniasis in three towns in the Santander department. METHODS: An ecologic design using housing as the analysis unit. Children aged less than ten were randomly selected from rural schools and visited in their homes by trained volunteers. Structured survey-forms were filled in and every child was examined for scars or active cutaneous leishmaniasis lesions. Cluster-adjusted binomial regression was used when analysing data. RESULTS: Eighteen villages, 284 houses and 609 children aged less than 10 were surveyed. Scar/lesion prevalence was 19.1%, differences being noted between municipalities: El Playón 7.1%, Landázuri 32.8% and Rionegro 13.9%. Information regarding leishmaniasis had been received by 42.8% of the houses and 39.9% had received some type of intervention from the Basic Colombian Health Plan, bed-nets being the most frequent (92.5%). Basic Health Plan intervention showed a preventative effect in bivariate analysis; however, such effect was not evident following adjustment for other socioeconomic and environmental variables (PR = 1.39 IC 95% 0.76-2.56). CONCLUSION: Basic health plan intervention for cutaneous leishmaniasis prevention has had no significant association with scar/lesion prevalence in children aged less than ten in these rural areas, probably because its effect has been exceeded by local socioeconomic and environmental conditions, as well as administrative conditions related to the programmes' poor coverage.

Animals↗
PubMed2005

Spatial and rainfall related patterns of bacterial contamination in Sydney Harbour estuary.

Water quality in recreational areas in Sydney Harbour, Australia, was analysed first to identify spatial patterns in faecal coliform and enterococci densities, and then to determine the relationship between bacterial densities and catchment rainfall. Non-metric multidimensional scaling separated sites closest to the mouth of the harbour from those further up the harbour's west and north-west arms. Sites closest to the harbour mouth generally had lower frequencies of high bacterial densities that exceeded median water quality guideline values. We attribute this to greater tidal flushing at sites closer to the harbour mouth. Eight site groups were identified within the harbour. Within each group, multiple regression analyses indicated rainfall accounted for between 15 and 66% of the variability in the bacterial densities. Variation in bacterial densities explained by rainfall was lower for sites closer to the harbour mouth where tidal flushing is greatest. Thus, our findings indicate that simple rainfall-based regression models are appropriate for predicting bacterial concentrations when flushing at a site is limited. More complex models incorporating a suite of environmental variables may improve the ability to predict bacterial concentrations at well-flushed sites, but even then, their predictive ability may be low.

Enterobacteriaceae↗
PubMed2002

Correlates of adults' participation in physical activity: review and update.

PURPOSE: To review and update the evidence relating to the personal, social, and environmental factors associated with physical activity (PA) in adults. METHODS: Systematic review of the peer-reviewed literature to identify papers published between 1998 and 2000 with PA (and including exercise and exercise adherence). Qualitative reports or case studies were not included. RESULTS: Thirty-eight new studies were located. Most confirmed the existence of factors already known to be correlates of PA. Changes in status were noted in relation to the influence of marital status, obesity, smoking, lack of time, past exercise behavior, and eight environmental variables. New studies were located which focused on previously understudied population groups such as minorities, middle and older aged adults, and the disabled. CONCLUSION: The newly reported studies tend to take a broader "ecological" approach to understanding the correlates of PA and are more focused on environmental factors. There remains a need to better understand environmental influences and the factors that influence different types of PA. As most of the work in this field still relies on cross-sectional studies, longitudinal and intervention studies will be required if causal relationships are to be inferred.

Adult↗
PubMed2006

Adaptive change in the resource-exploitation traits of a generalist consumer: the evolution and coexistence of generalists and specialists.

Mathematical models of consumer-resource systems are used to explore the evolution of traits related to resource acquisition in a generalist consumer species that is capable of exploiting two resources. The analysis focuses on whether evolution of traits determining the capture rates of two resources by a consumer species produce one generalist, two specialists, or all three types, when all types are characterized by a common fitness function. In systems with a stable equilibrium, evolution produces one generalist or two specialists, depending on the second derivative of the trade-off relationship. When there are sustained population fluctuations, the nature of the trade-off between the consumer's capture rates of the two resources still plays a key role in determining the evolutionary outcome. If the trade-off is described by a choice variable between zero and one that is raised to a power n, polymorphic states are possible when n > 1, which implies a positive second derivative of the curve. These states are either dimorphism, with two relatively specialized consumer types, or trimorphism, with a single generalist type and two specialists. Both endogenously driven consumer-resource cycles, and fluctuations driven by an environmental variable affecting resource growth are considered. Trimorphic evolutionary outcomes are relatively common in the case of endogenous cycles. In contrast to a previous study, these trimorphisms can often evolve even when new lineages are constrained to have phenotypes very similar to existing lineages. Exogenous cycles driven by environmental variation in resource growth rates appear to be much less likely to produce a mixture of generalists and specialists than are endogenous consumer-resource cycles.

Animals↗
PubMed2005

Evolution of genetic potential.

Organisms employ a multitude of strategies to cope with the dynamical environments in which they live. Homeostasis and physiological plasticity buffer changes within the lifetime of an organism, while stochastic developmental programs and hypermutability track changes on longer time-scales. An alternative long-term mechanism is "genetic potential"--a heightened sensitivity to the effects of mutation that facilitates rapid evolution to novel states. Using a transparent mathematical model, we illustrate the concept of genetic potential and show that as environmental variability decreases, the evolving population reaches three distinct steady state conditions: (1) organismal flexibility, (2) genetic potential, and (3) genetic robustness. As a specific example of this concept we examine fluctuating selection for hydrophobicity in a single amino acid. We see the same three stages, suggesting that environmental fluctuations can produce allele distributions that are distinct not only from those found under constant conditions, but also from the transient allele distributions that arise under isolated selective sweeps.

Journal Article↗
PubMed2004

Factors associated with women's and children's body mass indices by income status.

OBJECTIVE: To describe associations between eating behaviors, dietary intake, physical activity, attitudes toward diet and health, sociodemographic variables and body mass index (BMI) among women and children, and differences by household income. DESIGN: Data from the 1994-1996 Continuing Survey of Food Intakes by Individuals (CSFII) and the Diet and Health Knowledge Survey (DHKS) were examined using multivariate regression to estimate the associations between BMI and behavioral and environmental variables among women and children. SUBJECTS: CSFII 1994-1996 is representative of the US population. DHKS surveyed CSFII respondents 20 y of age and over. Our samples consisted of 2419 adult women and 1651 school-age children. MEASUREMENTS: CSFII respondents reported 24 h recalls of all food intakes on 2 nonconsecutive days and their personal and household characteristics, including self-reported height and weight. DHKS collected data on knowledge and attitudes toward dietary guidance and health from CSFII adult respondents. RESULTS: Significant correlations between women's BMI and age, race, dietary patterns, TV watching, and smoking was observed among women from both low- and high-income households. Beverage consumption, eating out, the importance of maintaining healthy weight, and exercise were correlated with BMI only among women from high-income households. Among children, age, race, income, and mother's BMI were significantly correlated with child BMI. CONCLUSIONS: Among women, the associations between some behavioral and environmental factors and BMI differ by household income. Intervention programs need to target specific eating and physical activity behaviors to promote a healthy body weight.

Adult↗
PubMed2003

Temporal and spatial changes of macroalgae and phytoplankton in a Mediterranean coastal area: the Venice lagoon as a case study.

Since the late 1980s the lagoon of Venice, a shallow Mediterranean coastal area, has experienced strong environmental changes. Macroalgae, which were the predominant primary producers of the lagoon, reduced markedly, but neither phytoplankton nor seagrasses replaced them. Temporal and spatial changes in macroalgal standing crop (SC) and phytoplankton concentration were investigated between 1987 and 1998. Maps of macroalgal SC show a marked declining trend. Biomass in fresh weight decreased from: 558 ktonnes in 1987, to 85 ktonnes in 1993 and to 8.7 ktonnes in 1998. As a whole, the biomass in 1998 was only 1.6% of the biomass recorded in 1987. Similarly the macroalgal net (NPP) and gross (GPP) primary production decreased from ca. 1502 and 9721 ktonnes year(-1) to ca. 44 and 229 ktonnes year(-1), respectively. In the early 1990s the clam Tapes philippinarum Adams & Reeve and seagrasses, especially Zostera marina Linnaeus, colonised the bottoms free of macroalgae, but the development of intense clam-fishing activities prevented both phytoplankton blooms and seagrass spreading. Maps of chlorophyll a drawn according to data collected in parallel to macroalgal standing crop show unchanged concentrations. Macroalgae changes are enhanced by comparing annual trends in four areas of the central lagoon during 1989-1992 and 1998-1999. In those areas phytoplankton also decreased significantly. Marked changes of some environmental variables strongly associated with the primary production were recorded both during the lagoon mapping and in the areas studied on a yearly basis.

Animals↗
PubMed1986

Female rats in a laboratory display seasonal variation in fecundity.

Female laboratory rats housed in controlled environments of two separate laboratories displayed seasonal variation in fecundity. Fecundity peaked between May and August and reached a trough between December and February, as measured by oestrous cycle length, variability and regularity, as well as number of animals mating and the percentage of litters reared to weaning. The percentage of mated animals giving birth remained constant throughout the year. Seasonal variations in the laboratory coincided with the seasonal cycle reported for wild rats in natural conditions. Several environmental variables, e.g. food, water, humidity and airborne factors, were evaluated as putative cues for seasonal variation.

Animals↗
PubMed1994

Violence in health care: institutional strategies to cope with the phenomenon.

Violence permeates every aspect of society, including the health care organization. Appropriate health care organizational response to the phenomenon of violence requires recognition that the emergence of violence is associated with patient, staff, situational, and environmental variables, and it is predictable in most instances. Effective management of violent patients requires comprehensive organizational policies, procedures, and protocols, combined with periodic staff training and retraining. Health care organizations and their personnel need to be knowledgeable about pre-assaultive clinical symptomatology, modification of staff behaviors and environmental factors with the goal of reducing the potential for violence, therapeutic interventions during both pre-assaultive and violent phases of patient behavior, and quality assurance and risk management issues implicit in managing violent patients.

Crisis Intervention↗
PubMed2002

Concomitant use of cigarettes and smokeless tobacco: prevalence, correlates, and predictors of tobacco cessation.

BACKGROUND: This study examined the characteristics, tobacco use patterns over time, and predictors of tobacco cessation among concomitant users of cigarettes and smokeless tobacco. METHODS: Participants were employed adults residing in the southeastern United States who participated in the Working Well cancer prevention trial. Participants were assessed at baseline and followed-up 4 years later. RESULTS AND CONCLUSIONS: The study yielded several key findings: (a) the prevalence of concomitant smoking and smokeless tobacco use was high among males and nonexistent among females, (b) the characteristics of concomitant users were relatively distinct from those of both smokers and smokeless tobacco users, (c) concomitant users exhibited substantial variability in their tobacco use patterns and were less likely to stop using tobacco than were smokers or smokeless tobacco users, (d) indicators of nicotine dependence predicted tobacco cessation for both smokers and smokeless tobacco users, but were largely unrelated to tobacco cessation among concomitant users, and (e) demographics, environmental variables, and measures derived from the transtheoretical model were not consistent predictors of tobacco cessation after controlling for nicotine dependence.

Adult↗
PubMed1999

Environmental covariates: effects on the power of sib-pair linkage methods.

The effect of inclusion of environmental risk factors on the power of sib-pair linkage methods was tested for a qualitative trait. It was found that inclusion of an environmental variable did not increase the power of the Haseman-Elston (H-E) sib-pair nonparametric linkage analysis test. However, a significant increase in power was observed for both the H-E and affected-sib-pair tests, even in small samples, when persons unexposed to the environmental risk factor were coded as unknown.

Environment↗
PubMed2000

Resemblance for body mass index in families of obese African American and European American women.

OBJECTIVE: We determined the levels of resemblance in body mass index (BMI) in large samples of families selected through obese African American and European American women. RESEARCH METHODS AND PROCEDURES: We examined correlations among relatives in 1,185 European American and African American families ascertained through age-matched obese women (BMI > or = 30 kg/m2). A subset of 801 families were ascertained through extremely obese women (BMI > or = 40 kg/m2). RESULTS: Parent-offspring and sibling correlations ranged from 0.19 to 0.15, suggesting a moderate level of heritability in both groups. Mean BMI values for female relatives were lower for European Americans than for African Americans even though probands were matched, perhaps because the European American relatives regress to a lower population mean. We found significantly higher family correlations for height in European Americans, suggesting greater environmental variability among African Americans for factors affecting growth and physical development. DISCUSSION: Our results suggest a similar level of heritability of BMI in families of obese African American and European American women. Other genetic studies will be needed to determine the extent to which the same or different genes and environmental conditions contribute to an overall similar heritability in the two racial groups.

Adolescent↗
PubMed2002

Phylogeography of the socially polymorphic sweat bee Halictus rubicundus (Hymenoptera: Halictidae).

The evolution of sociality in insects holds a central place in evolutionary theory. By examining the phylogenetic patterns of solitary and social behavior and how they correlate with ecological variables, we may identify factors important in the evolution of sociality. In this study, we investigated historical and biogeographical patterns of sociality in a socially polymorphic bee species (one that demonstrates both social and solitary nesting behavior). This unique system allows for a more powerful examination of evolutionary transitions in sociality than interspecific studies of obligately social and solitary species. We conducted a phylogenetic analysis among populations of the halictine bee Halictus rubicundus and then identified relationships among mitochondrial DNA sequence data, sociality, environmental conditions at the nesting site, and geographic location of populations of this species. Within North America, populations of H. rubicundus expressing social and solitary behavior belong to different genetic lineages. Sociality is also correlated with at least one environmental variable used in this study. Taken together, the results support the predictions for genetic control of sociality, but they are still consistent with social behavior at some level being determined by the environmental conditions at the nesting site.

Altitude↗
PubMed2004

Adaptation and constraint in the evolution of environmental sex determination.

When environments differentially influence male and female performance, environmental sex determination (ESD) might evolve. The conclusion from several previous theoretical models was that reaction norms for sex determination should have a single, sharp threshold, with only females being produced in some environments and only males in others. These reaction norms can be disadvantageous in fluctuating environments, however, because they lead to sex-ratio fluctuations. We analysed the evolution of ESD, looking for equilibrium strategies in unconstrained as well as constrained strategy spaces. We identified situations where a single-threshold reaction norm is not evolutionarily stable. In these cases, we found stable strategies in the form of complex reaction norms, showing an oscillatory pattern of sex determination with respect to variation in an environmental variable. Considering that constraints could prevent such phenotypes from being realized, we found that certain randomized reaction norms, with probabilistic sex determination for a range of environments, would achieve nearly the same fitness. We also investigated reaction norms constrained to have a single threshold and found that genetic polymorphism in the environmental threshold value could evolve, producing a similar effect as a randomized reaction norm. We argue that the appearance of genetic variation can be regarded as an alternative outcome when constraints prevent the evolution of a more complex or a randomized strategy.

Adaptation, Physiological↗