SEARCH · PubMed Health

Results for “Environment”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources

PubMed1995

Evolution in heterogeneous environments: genetic variability within and across different grains in Tribolium castaneum.

The course of adaptation to heterogeneous environments is influenced by the magnitude of genetic variation for ecologically important characters within each environment and the extent of genotype x environment interaction. Using the genetic correlation between the expression of characters in different environments as a measure of genotype x environment interaction is particularly useful for evolutionary interpretation. In this study, we estimated patterns of genetic variability and cross-environment genetic correlations for pupal weight and development time in two strains of the flour beetle Tribolium castaneum in five flours (wheat with brewer's yeast, wheat, rice, corn and oat). Wheat plus yeast is the standard medium in which the strains have been reared for hundreds of generations; other flours are novel environments. The results indicated moderate levels of genetic variation within the various flours for pupal weight but not for development time. Performance varied considerably across flours, with the highest performance for both strains found in the standard medium and the poorest in oat flour. The genetic correlations of pupal weight across flours in both strains were generally not significantly different from + 1. This suggests that evolution of body size in different flours cannot proceed independently, and that improved performance in the novel flours may produce declines in fitness in the standard environment.

Animals↗

PubMedDate not supplied

Developmental flexibility and the effect of social environment on fertility and fecundity in parthenogenetic reproduction.

One specialized environment that can influence development arises in the context of social interactions, including the environment contributed by a sexual partner during sexual reproduction. It is often difficult, however, to separate out the effect of mating (fertilization) from the effect of social environment. In the study reported here we examine the effect of social environment mediated by a pheromonal signal on the fertility and fecundity of the facultatively parthenogenetic cockroach Nauphoeta cinerea. By examining parthenogenetically reproducing females, we isolate the effects of social environment in the absence of mating or fertilization. Females exposed to male odors are more likely to produce parthenogenetic offspring. Further, increased exposure to the male pheromone increases the number of offspring produced. Variation in timing of reproduction is also dependent on the male. Thus, social environments are a mechanism by which males contribute to the development of their offspring, resulting in variation in development. This study illustrates the potential evolutionary importance of social environments in development, because a requirement for male-contributed environments may be a constraint to evolving asexual reproduction from a sexually reproducing species.

Analysis of Variance↗

PubMedDate not supplied

Occupant perception of indoor air and comfort in four hospitality environments.

This article reports on a survey of customer and staff perceptions of indoor air quality at two restaurants, a billiard hall, and a casino. The survey was conducted at each environment for 8 days: 2 weekend days on 2 consecutive weekends and 4 weekdays. Before and during the survey, each hospitality environment satisfied ventilation requirements set in ASHRAE Standard 62-1999, Ventilation for Acceptable Indoor Air. An objective of this study was to test the hypothesis: If a hospitality environment satisfies ASHRAE ventilation requirements, then the indoor air is acceptable, that is, fewer than 20% of the exposed occupants perceive the environment as unacceptable. A second objective was to develop a multiple regression model that predicts the dependent variable, the environment is acceptable, as a function of a number of independent perception variables. Occupant perception of environmental, comfort, and physical variables was measured using a questionnaire. This instrument was designed to be efficient and unobtrusive; subjects could complete it within 3 min. Significant differences of occupant environment perception were identified among customers and staff. The dependent variable, the environment is acceptable, is affected by temperature, occupant density, and occupant smoking status, odor perception, health conditions, sensitivity to chemicals, and enjoyment of activities. Depending on the hospitality environment, variation of independent variables explains as much as 77% of the variation of the dependent variable.

Air Pollution, Indoor↗

PubMed2000

Family environment in attention deficit hyperactivity, oppositional defiant and conduct disorders.

OBJECTIVE: This study aims to ascertain whether there were differences in family environment among patients with attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder and conduct disorder. METHOD: The records of 233 patients, selected for high or low scores on a scale that taps ADHD symptoms, were reviewed by three clinicians who made DSM-IV diagnoses and rated the family environment with the Global Family Environment Scale (GFES). Self-report data obtained from the parent and child versions of the Child Behaviour Checklist were also used. The quality of the family environment was then compared between the various diagnostic groups. RESULTS: A poorer family environment was associated with conduct disorder and oppositional defiant disorder and predicted a worse outcome (e.g. admission to a non-psychiatric institution, drug and alcohol abuse). Quality of the family environment did not vary according to ADHD diagnosis or gender. CONCLUSIONS: There seems to be no association between the quality of the family environment and a diagnosis of ADHD among referred adolescents. However, there is an association with conduct disorder. Interventions that improve family environment in the early years of life may prevent the development of conduct problems.

Adolescent↗

PubMed2005

Experimental evolution of Pseudomonas fluorescens in simple and complex environments.

In complex environments that contain several substitutable resources, lineages may become specialized to consume only one or a few of them. Here we investigate the importance of environmental complexity in determining the evolution of niche width over approximately 900 generations in a chemically defined experimental system. We propagated 120 replicate lines of the bacterium Pseudomonas fluorescens in environments of different complexity by using between one and eight carbon substrates in each environment. Genotypes from populations selected in complex environments evolved greater mean and variance in fitness than those from populations selected in simple environments. Thus, lineages were able to adapt to several substrates simultaneously without any appreciable loss of function with respect to other substrates present in the media. There was greater genetic and genotype-by-environment interaction variance for fitness within populations selected in complex environments. It is likely that genetic variance in populations grown on complex media was maintained because the identity of the fittest genotype varied among carbon substrates. Our results suggest that evolution in complex environments will result neither in narrow specialists nor in complete generalists but instead in overlapping imperfect generalists, each of which has become adapted to a certain range of substrates but not to all.

Bacterial Typing Techniques↗

PubMed2003

Sonic intelligence as a virtual therapeutic environment.

This paper reports on the results of a research project, on comparing one virtual collaborative environment with a first-person visual immersion (first-perspective interaction) and a second one where the user interacts through a sound-kinetic virtual representation of himself (avatar), as a stress-coping environment in real-life situations. Recent developments in coping research are proposing a shift from a trait-oriented approach of coping to a more situation-specific treatment. We defined as real-life situation a target-oriented situation that demands a complex coping skills inventory of high self-efficacy and internal or external "locus of control" strategies. The participants were 90 normal adults with healthy or impaired coping skills, 25-40 years of age, randomly spread across two groups. There was the same number of participants across groups and gender balance within groups. All two groups went through two phases. In Phase I, Solo, one participant was assessed using a three-stage assessment inspired by the transactional stress theory of Lazarus and the stress inoculation theory of Meichenbaum. In Phase I, each participant was given a coping skills measurement within the time course of various hypothetical stressful encounters performed in two different conditions and a control group. In Condition A, the participant was given a virtual stress assessment scenario relative to a first-person perspective (VRFP). In Condition B, the participant was given a virtual stress assessment scenario relative to a behaviorally realistic motion controlled avatar with sonic feedback (VRSA). In Condition C, the No Treatment Condition (NTC), the participant received just an interview. In Phase II, all three groups were mixed and exercised the same tasks but with two participants in pairs. The results showed that the VRSA group performed notably better in terms of cognitive appraisals, emotions and attributions than the other two groups in Phase I (VRSA, 92%; VRFP, 85%; NTC, 34%). In Phase II, the difference again favored the VRSA group against the other two. These results indicate that a virtual collaborative environment seems to be a consistent coping environment, tapping two classes of stress: (a) aversive or ambiguous situations, and (b) loss or failure situations in relation to the stress inoculation theory. In terms of coping behaviors, a distinction is made between self-directed and environment-directed strategies. A great advantage of the virtual collaborative environment with the behaviorally enhanced sound-kinetic avatar is the consideration of team coping intentions in different stages. Even if the aim is to tap transactional processes in real-life situations, it might be better to conduct research using a sound-kinetic avatar based collaborative environment than a virtual first-person perspective scenario alone. The VE consisted of two dual-processor PC systems, a video splitter, a digital camera and two stereoscopic CRT displays. The system was programmed in C++ and VRScape Immersive Cluster from VRCO, which created an artificial environment that encodes the user's motion from a video camera, targeted at the face of the users and physiological sensors attached to the body.

Adaptation, Psychological↗

PubMed1991

Mendelian factors underlying quantitative traits in tomato: comparison across species, generations, and environments.

As part of ongoing studies regarding the genetic basis of quantitative variation in phenotype, we have determined the chromosomal locations of quantitative trait loci (QTLs) affecting fruit size, soluble solids concentration, and pH, in a cross between the domestic tomato (Lycopersicon esculentum Mill.) and a closely-related wild species, L. cheesmanii. Using a RFLP map of the tomato genome, we compared the inheritance patterns of polymorphisms in 350 F2 individuals with phenotypes scored in three different ways: (1) from the F2 progeny themselves, grown near Davis, California; (2) from F3 families obtained by selfing each F2 individual, grown near Gilroy, California (F3-CA); and (3) from equivalent F3 families grown near Rehovot, Israel (F3-IS). Maximum likelihood methods were used to estimate the approximate chromosomal locations, phenotypic effects (both additive effects and dominance deviations), and gene action of QTLs underlying phenotypic variation in each of these three environments. A total of 29 putative QTLs were detected in the three environments. These QTLs were distributed over 11 of the 12 chromosomes, accounted for 4.7-42.0% of the phenotypic variance in a trait, and showed different types of gene action. Among these 29 QTLs, 4 were detected in all three environments, 10 in two environments, and 15 in only a single environment. The two California environments were most similar, sharing 11/25 (44%) QTLs, while the Israel environment was quite different, sharing 7/20 (35%) and 5/26 (19%) QTLs with the respective California environments. One major goal of QTL mapping is to predict, with maximum accuracy, which individuals will produce progeny showing particular phenotypes. Traditionally, the phenotype of an individual alone has been used to predict the phenotype of its progeny. Our results suggested that, for a trait with low heritability (soluble solids), the phenotype of F3 progeny could be predicted more accurately from the genotype of the F2 parent at QTLs than from the phenotype of the F2 individual. For a trait with intermediate heritability (fruit pH), QTL genotype and observed phenotype were about equally effective at predicting progeny phenotype. For a trait with high heritability (mass per fruit), knowing the QTL genotype of an individual added little if any predictive value, to simply knowing the phenotype. The QTLs mapped in the L. esculentum X L. cheesmanii F2 appear to be at similar locations to many of those mapped in a previous cross with a different wild tomato (L. chmielewskii).(ABSTRACT TRUNCATED AT 400 WORDS)

Biological Evolution↗

PubMed2003

Conducting research on home environments: lessons learned and new directions.

The study of home environments is a research domain within the field of environmental gerontology that addresses issues related to aging in place. Despite the importance of aging at home, there are few recent studies in this area and most are descriptive and lack theoretical direction. This article examines the current state of research on home environments from which methodological challenges and new directions for future research are identified. Three broad research queries are posed: What should we measure and why in home environments? How do older people and their family members use the home environment in health, illness, and caregiving? What are the interrelationships between the home environment, psychological well-being, and daily functioning throughout the aging process? Suggestions for future research on home environments are discussed and the implications for advancing environmental gerontology highlighted. Specifically, the home environment offers a testing ground for generic environmental constructs and their measurement as well as a unique setting from which new understandings and constructs of person-environment fit can emerge.

Activities of Daily Living↗

PubMed2001

Effects of home environment, socioeconomic status, and health status on cognitive functioning in children with HIV-1 infection.

OBJECTIVE: To investigate the effects of the home environment, socioeconomic status (SES), and health status on cognitive functioning in a sample of children with HIV-1 infection in a cross-sectional study. METHODS: Forty-three caregivers and their children (2.5 to 12 years) participated. Caregivers completed two self-report measures of the home environment that included questions regarding the organization of the environment, play materials, parental involvement, variety of stimulation, and parental attitudes toward the provision of a cognitively stimulating environment. Cognitive functioning was assessed using a standardized intelligence (IQ) test. Children's medical charts were reviewed for HIV-1 classification status (CDC, 1994), CD4 cell counts, and current medication. RESULTS: This study revealed two primary findings. First, measures of the home environment mediated the association between SES and child IQ. Second, measures of the home environment had a stronger association with child IQ during the advanced stages of disease than earlier stages of disease. CONCLUSIONS: The home environment is associated with cognitive functioning among children with HIV-1 infection. Moreover, interventions aimed at enhancing the quality of the home environment may have a positive impact on these children's cognitive development.

Child↗

PubMed2003

Residential environments and cardiovascular risk.

The article begins with a discussion of the rationale for studying the relationship between residential environments and cardiovascular health. Existing empirical research relating residential environments to cardiovascular outcomes and risk factors is summarized. The research areas discussed include neighborhood socioeconomic characteristics and cardiovascular disease, the effects of residential environments on physical activity, and the effects of residential environments on diet. Other mechanisms through which residential environments may affect cardiovascular health are also briefly noted. Key challenges in investigating the relationship between residential environments and health are discussed. These challenges include characterizing environments (including definition and geographic scale as well as conceptualization and measurement of relevant features), the limitations of observational studies, and the need to evaluate the health impact of interventions or "naturally" occurring changes in local environments. The need for interdisciplinary work is emphasized.

Cardiovascular Diseases↗

PubMedDate not supplied

Impact of social environment characteristics on neuroendocrine regulation.

OBJECTIVE: This article reviews evidence relating social environment characteristics to patterns of neuroendocrine regulation. To date, although there has been considerable interest in the effects of social ties and support on health and longevity, less attention has been given to the effects of such social environment characteristics on actual physiologic parameters. METHOD: Animal and human studies from 1960s to the present are reviewed for evidence linking social environment characteristics to patterns of hypothalamic-pituitary-adrenal (HPA) axis, sympathetic nervous system (SNS), and cardiovascular activity. RESULTS: Community and laboratory-based studies document that characteristics of the social environment influence patterns of neuroendocrine reactivity. These effects seem to be highly sensitive to aspects of the social environment such as relative social status, the relative stability of the social ordering and, importantly, the quality of social relationships. Although supportive social relationships are often associated with attenuated patterns of HPA and SNS activation, the converse also seems to be true as nonsupportive social interactions are frequently associated with enhanced reactivity. CONCLUSION: Available evidence regarding links between social environment characteristics and neuroendocrine regulation documents a link between the social and biological realms that may have important consequences for health and longevity. The data provide support for the hypothesis that observed associations between social ties and health and longevity result, at least partially, from the positive influence of such social environment characteristics in reducing neuroendocrine reactivity. The evidence regarding nonsupportive or hostile social relationships highlights the importance of taking a broader view of the potential health effects of the social environment, one that encompasses the potential for both positive and negative effects.

Adult↗

PubMed2004

CREB deficient mice show inhibition and low activity in novel environments without changes in stress reactivity.

The ability to respond to unexpected or novel stimuli is critical for survival. Determining that a stimulus is indeed novel requires memory to ascertain its lack of familiarity. As the long-term synaptic changes involved in memory formation require the cAMP response element binding protein (CREB), we examined the extent to which CREB is involved in responses to novel environments. These environments typically trigger an endocrine stress response. Thus, we measured behavioural and stress hormone responses to three novel and one familiar environment in mice with a targeted disruption of the alpha and delta isoforms of the CREB gene (CREB(alphadelta-) deficient mice). We found CREB(alphadelta-) deficient mice to be less active and more inhibited in the elevated plus maze, open field, and light/dark box, without showing differences in anxiety-like behaviour. This inhibition is unique to novel environments because these mice display a normal phenotype in the home cage, a familiar environment. Although CREB(alphadelta-) deficient mice exhibit altered behaviour in novel environments, they show normal reactivity to mild and moderate stress as both basal and stress levels of corticosterone are similar to those of wild-type controls. This is the first report of CREB(alphadelta-) deficient mice to: (i) show altered behaviour, not related to learning and memory-associated behaviours, upon initial exposure to environments and (ii) serve as an animal model that can dissociate locomotor activity from anxiety-like behaviour in novel environments.

Animals↗

PubMed1997

Health psychology: what is an unhealthy environment and how does it get under the skin?

This review explores the role of environments in creating chronic and acute health disorders. A general framework for studying the nesting of social environments and the multiple pathways by which environmental factors may adversely affect health is offered. Treating socioeconomic status (SES) and race as contextual factors, we examine characteristics of the environments of community, work, family, and peer interaction for predictors of positive and adverse health outcomes across the lifespan. We consider chronic stress/allostatic load, mental distress, coping skills and resources, and health habits and behaviors as classes of mechanisms that address how unhealthy environments get "under the skin," to create health disorders. Across multiple environments, unhealthy environments are those that threaten safety, that undermine the creation of social ties, and that are conflictual, abusive, or violent. A healthy environment, in contrast, provides safety, opportunities for social integration, and the ability to predict and/or control aspects of that environment.

Behavioral Medicine↗

PubMed2006

Validity of a virtual environment for stroke rehabilitation.

BACKGROUND AND PURPOSE: Virtual environments for use in stroke rehabilitation are in development, but there has been little evaluation of their suitability for this purpose. We evaluated a virtual environment developed for the rehabilitation of the task of making a hot drink. METHODS: Fifty stroke patients undergoing rehabilitation in a UK hospital stroke unit were involved. The performance of stroke rehabilitation patients when making a hot drink had the neurological impairments associated with performance of this task, and the errors observed were compared for standardized task performance in the real world and in a virtual environment. Neurological impairments were measured using standardized assessments. Errors in task performance were assessed rating video recordings and classified into error types. RESULTS: Real-world and virtual environment performance scores were not strongly associated (rho=0.30; P<0.05). Performance scores in both settings were associated with age, Barthel ADL score, Mini Mental State Examination score, and tests of visuospatial function. Real-world performance only was associated with arm function and sequencing ability. Virtual environment performance only was associated with language function and praxis. Participants made different errors during task performance in the real world and in the virtual environment. CONCLUSIONS: Although this virtual environment was usable by stroke rehabilitation patients, it posed a different rehabilitation challenge from the task it was intended to simulate, and so it might not be as effective as intended as a rehabilitation tool. Other virtual environments for stroke rehabilitation in development require similar evaluation.

Activities of Daily Living↗

PubMedDate not supplied

Response to mass selection when the genotype by environment interaction is modelled as a linear reaction norm.

A breeding goal accounting for the effects of genotype by environment interaction (G x E) has to define not only traits but also the environment in which those traits are to be improved. The aim of this study was to predict the selection response in the coefficients of a linear reaction norm, and response in average phenotypic value in any environment, when mass selection is applied to a trait where G x E is modelled as a linear reaction norm. The optimum environment in which to test the selection candidates for a given breeding objective was derived. Optimisation of the selection environment can be used as a means to either maximise genetic progress in a certain response environment, to keep the change in environmental sensitivity at a desired rate, or to reduce the proportion of animals performing below an acceptance level. The results showed that the optimum selection environment is not always equal to the environment in which the response is to be realised, but depends on the degree of G x E (determined by the ratio of variances in slope and level of a linear reaction norm), the correlation between level and slope, and the heritability of the trait.

Animals↗

PubMed2002

Beneficial effects of enriched environment following status epilepticus in immature rats.

BACKGROUND: There is increasing evidence that enriching the environment can improve cognitive and motor deficits following a variety of brain injuries. Whether environmental enrichment can improve cognitive impairment following status epilepticus (SE) is not known. OBJECTIVE: To determine whether the environment in which animals are raised influences cognitive function in normal rats and rats subjected to SE. METHODS: Rats (n = 100) underwent lithium-pilocarpine-induced SE at postnatal (P) day 20 and were then placed in either an enriched environment consisting of a large play area with toys, climbing objects, and music, or in standard vivarium cages for 30 days. Control rats (n = 32) were handled similarly to the SE rats but received saline injections instead of lithium-pilocarpine. Rats were then tested in the water maze, a measure of visual-spatial memory. A subset of the rats were killed during exposure to the enriched or nonenriched environment and the brains examined for dentate granule cell neurogenesis using bromodeoxyuridine (BrdU) and phosphorylated cyclic AMP response element binding protein (pCREB) immunostaining, a brain transcription factor important in long-term memory. RESULTS: Both control and SE rats exposed to the enriched environment performed significantly better than the nonenriched group in the water maze. There was a significant increase in neurogenesis and pCREB immunostaining in the dentate gyrus in both control and SE animals exposed to the enriched environment compared to the nonenriched groups. Environmental enrichment resulted in no change in SE-induced histologic damage. CONCLUSIONS: Exposure to an enriched environment in weanling rats significantly improves visual-spatial learning. Even following SE, an enriched environment enhances cognitive function. An increase in neurogenesis and activation of transcription factors may contribute to this enhanced visual-spatial memory.

Age Factors↗

PubMed2006

The role of built environments in physical activity, eating, and obesity in childhood.

Over the past forty years various changes in the U.S. "built environment" have promoted sedentary lifestyles and less healthful diets. James Sallis and Karen Glanz investigate whether these changes have had a direct effect on childhood obesity and whether improvements to encourage more physical activity and more healthful diets are likely to lower rates of childhood obesity. Researchers, say Sallis and Glanz, have found many links between the built environment and children's physical activity, but they have yet to find conclusive evidence that aspects of the built environment promote obesity. For example, certain development patterns, such as a lack of sidewalks, long distances to schools, and the need to cross busy streets, discourage walking and biking to school. Eliminating such barriers can increase rates of active commuting. But researchers cannot yet prove that more active commuting would reduce rates of obesity. Sallis and Glanz note that recent changes in the nutrition environment, including greater reliance on convenience foods and fast foods, a lack of access to fruits and vegetables, and expanding portion sizes, are also widely believed to contribute to the epidemic of childhood obesity. But again, conclusive evidence that changes in the nutrition environment will reduce rates of obesity does not yet exist. Research into the link between the built environment and childhood obesity is still in its infancy. Analysts do not know whether changes in the built environment have increased rates of obesity or whether improvements to the built environment will decrease them. Nevertheless, say Sallis and Glanz, the policy implications are clear. People who have access to safe places to be active, neighborhoods that are walkable, and local markets that offer healthful food are likely to be more active and to eat more healthful food-two types of behavior that can lead to good health and may help avoid obesity.

Child↗

PubMed2003

Genotype by environment interaction for yield and somatic cell score with alternative environmental definitions.

Differential genetic expression in high and low opportunity Sicilian Holstein-Friesian and Brown Swiss herd environments was investigated using endogenous and exogenous variables in a set of three definitions. Results of genetic by environmental interaction were compared using alternative environmental definitions: within herd-year standard deviation for mature equivalent milk yield (HYSD), detectable incidence of normal vs. abnormal (peakless) lactation and herds clustered by causal relationships from high and low frequency use of nutrition, milking, health and animal handling practices. Data for genetic analysis consisted of first-lactation standardized yields of milk, fat and protein, and weighted somatic cell score for 8897 daughters of 825 Holstein-Friesian sires and 1143 daughters of 220 Brown Swiss sires. Components of covariance, heritabilities, and genetic correlations were estimated using bivariate and multivariate sire models for average and contrasting environments for each definition. Sire variances for yields were consistently smaller in the low opportunity environments of both breeds. Except for differential incidence of abnormal lactation in Friesian herds, correlated yield response in less privileged environments was 0.41 to 0.81 as much as in high opportunity environments, a substantial loss. Genetic correlations between HYSD environments for yield traits of Friesian were 0.48 to 0.66 but exceeded 0.80 for other definitions. Less correlated response in somatic cell score was also predicted for environments with low use of yield-enhancing practices (0.66 for Friesian and 0.61 for Brown Swiss), which may have resulted from less health care and poorer milking management. Therefore, unfavorable management interactions likely foster unequal gains from selection in contrasting environments defined exogenously or by incidence of peakless lactation. Conversely, greater genetic as well as phenotypic response is expected from additional inputs of nutrition, health care and milking management.

Analysis of Variance↗