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PubMed1996

Susceptibility of electro-optic components to degradation in a space environment.

Possible causes of degradation of electro-optic systems operating in a space environment include not only the effects of radiation but also the effects of temperature, temperature cycling, atomic oxygen effects (for low-Earth orbits), micrometeoroid impacts, and contamination effects. For the majority of electro-optic components, the radiation environment in space does not present a significant problem. For a few components, or for electro-optic systems that must operate in a high radiation environment, special precautions must be observed. The effects of radiation, as well as other problems of the space environment, on electro-optic components, including recent results from the LDEF satellite experiments and some later measurements, are reviewed. Guidelines for materials and component selection shielding are presented.

Extraterrestrial Environment↗

PubMed1992

Twins' perception of their environment: a cross-cultural comparison of changes over time.

In a previous Swedish twin project (the SLU-project), approximately 300 MZ and DZ twin pairs and controls were followed through the Swedish compulsory school from grade 3 to grade 9. Results from this study indicated an increase of genetic influences on school achievement over time for children from a permissive home environment and a decrease for children from a restrictive home environment. These types of data have generated a more general model for studying heredity-environment interaction in educational settings. To test this model, a cross-cultural comparison over time of twins and controls in the Israeli kibbutz school and in the Swedish compulsory school has been made. Restrictions on the child were originally assumed to be more apparent in the kibbutz environment.

Adolescent↗

PubMed2006

Campylobacter in waterfowl and aquatic environments: incidence and methods of detection.

Campylobacters are emerging as one of the most significant causes of human infections worldwide, and the role that waterfowl and the aquatic environment have in the spread of disease is beginning to be elucidated. On a world scale campylobacters are possibly the major cause of gastrointestinal infections. Campylobacters are common commensals in the intestinal tract of many species of wild birds, including waterfowl. They are also widely distributed in aquatic environments where their origins may include waterfowl as well as sewage effluents and agricultural runoff. Campylobacters have marked seasonal trends. In temperate aquatic environments they peak during winter, whereas spring-summer is the peak period for human infection. Campylobacter species may survive, and remain potentially pathogenic, for long periods in aquatic environments. The utility of bacterial fecal indicators in predicting the presence of campylobacters in natural waters is questionable. Viable but nonculturable Campylobacter cells may occur, but whether they have any role in the generation of outbreaks of campylobacteriosis is unclear. The routine detection of Campylobacter spp. in avian feces and environmental waters largely relies on conventional culture methods, while the recognition of a particular species or strain is based on serotyping and increasingly on molecular methods. Thus, PCR combined with selective enrichment enhances the detection of campylobacters in water and feces, while DNA sequencing facilitates recognition of particular species and strains.

Animals↗

PubMed1999

Influence of the chemical environment on metolachlor conformations.

Metolachlor exists in multiple, different stable conformations in solution. Assignment of the NMR frequencies to chemical structure is a prerequisite to understanding the behavior of individual conformations. (1)H NMR experiments of metolachlor in different chemical environments identified the labile sites of metolachlor and environments that influence conformational/configurational changes. Within very specific chemical environments, metolachlor atropisomers aS,12S (aR,12R) and aR,12S (aS,12R) freely interchange, and consequently, the multiple conformations also interchange. The changes in chemical environments, which most alter the conformations and molecular dynamics of metolachlor, identify the most critical components affecting its environmental fate. These results enable a structural interpretation of conformational changes that can influence the environmental fate of metolachlor.

Acetamides↗

PubMed2004

Interactive effects of genotype, environment, and ontogeny on resistance of cucumber (Cucumis sativus) to the generalist herbivore, Spodoptera exigua.

Host-plant genotype, environment, and ontogeny all play a role in determining plant resistance to herbivory, yet little is known about the nature of the interactions among these factors. We investigated resistance of cucumber plants Cucumis sativus to the generalist herbivore Spodoptera exigua in a manipulative experiment involving three factors. In particular, we tested the effects of bitter (cucurbitacins present) vs. sweet (cucurbitacins absent) plants (genotype), with or without previous herbivory (environment), and cotyledons vs. true leaves (ontogeny). Contrary to our expectations, S. exigua growth was 54% higher on bitter plants than on sweet plants; growth was 63% higher, however, on undamaged plants compared to damaged plants, and 59% higher on true leaves compared to cotyledons. Moreover, all two-way interaction terms between genotype, environment, and ontogeny were significant. For example, S. exigua performance was higher on bitter than on sweet plants; however, this effect was strongly influenced by whether the tissue consumed was a cotyledon or true leaf and also whether it had been previously damaged. An examination of leaf nutritional chemistry revealed that some of our results could be explained by genotypic, environmental, and ontogenic differences in foliar nitrogen content. In contrast, the cucurbitacin content of plants did not appear to affect caterpillar growth. Our results provide evidence for the importance of interactions between genotype, environment, and ontogeny in determining herbivory and illustrate the value of manipulative experiments in revealing the complexities of these interactions.

Adaptation, Physiological↗

PubMed2004

Family environments of women seeking BRCA1/BRCA2 genetic mutation testing: an exploratory analysis.

Although there is some understanding of the shared characteristics and predictors of psychological distress of women participating in hereditary breast and ovarian cancer registries, these same characteristics are only beginning to be identified in research on community women seeking genetic testing for BRCA1/BRCA2 gene mutations. This study provides an initial exploration of characteristics associated with family environments for 51 community women waiting to receive such genetic testing results. Thirty-four of the 36 women classified on family environment type of the Family Environment Scale (FES) were from Personal Growth-Oriented families. Comparisons of women with and without personal cancer histories resulted in a trend for women with personal cancer histories to be classified as from Independence-Oriented families. Reported distress appears to vary for different family emphases based on family and personal cancer history. A moral-religious family emphasis consistently appeared to be associated with decreased psychological distress. Preliminary analyses comparing these community women (who were not part of a hereditary registry but were self- or physician-referred) seeking genetic testing with normal and distressed family means found that increased cohesion and expressiveness may be related to decreased conflict, indicative of potentially supportive family environments for these women. When compared with normative data, a subset consisting of the Ashkenazi Jewish women showed a trend of less cohesion than normal families, but similar cohesion levels as distressed families.

Adaptation, Psychological↗

PubMed1993

Early family environments and traumatic experiences associated with borderline personality disorder.

Childhood trauma experiences (e.g., sexual abuse, physical abuse, witnessed violence, and early separation experiences) and family environment characteristics were assessed with a questionnaire from a sample of depressed female inpatients; 17 were diagnosed as having borderline personality disorder (BPD), and 19 received no such diagnosis (NBPD). Significantly more BPD individuals than NBPD individuals reported histories of sexual abuse, physical abuse, and witnessed violence. Of these trauma variables, sexual abuse emerged as the only significant predictor of dimensional BPD score, even after physical abuse, subjective depression score, diagnostic differences between groups, and family environment were controlled. Early separation experiences were nonsignificantly different between groups. Although the BPD families were reported to be distinctive for several different family environment characteristics, the control dimension significantly predicted dimensional borderline score even after sexual abuse was controlled. These results suggest that sexual abuse and general family environment need further study for a fuller understanding of BPD symptomatology.

Adolescent↗

PubMed1989

Familial environment associated with type A behaviors and psychophysiological responses to stress in children.

This study tested two major hypotheses regarding the characteristics of family environments associated with children's Type A behaviors, anger frequency and expression, hostile outlook, hostility displayed during an interview, and cardiovascular responses to laboratory stressors. Two measures of family environment, Positive Affiliation and Authoritarianism, were derived by a factor analysis of the Family Environment Scale completed by parents. The sample consisted of 66 girls and 48 boys enrolled in Grades 2 through 12 from 114 families residing in a predominantly White, upper-middle-class suburb of Pittsburgh. Analyses largely supported the first hypothesis--that a less supportive and positively involved family climate would be associated with attributes of potential coronary heart disease (CHD) risk in children. Families scoring low on Positive Affiliation had children who were assessed as more angry and hostile on the basis of questionnaires and interview. Boys from these families had a more pronounced heart rate response to all laboratory stressors. The second hypothesis--that authoritarianism, in the absence of positive involvement and supportiveness in the family, would be associated with attributes of potential CHD risk in children--received support in regard to boys' heart rate responses to the serial-subtraction and mirror-image-tracing tasks. High Authoritarianism scores in combination with low Positive Affiliation scores in families predicted a heightened heart rate response in boys. Sex differences in the pattern of associations among family and child characteristics were also found. Results suggest that factors in the family environment may be important influences in children's development of characteristics that may, in adulthood, place them at risk for CHD.

Adolescent↗

PubMed1986

Persistence of visual cortex dendritic alterations induced by postweaning exposure to a "superenriched" environment in rats.

To assess the relative permanence of dendritic alterations induced by postweaning housing conditions, dendritic field parameters in the occipital cortex were compared among rats that had spent 30 days, beginning at 23-25 days of age, in a "superenriched" environment, rats that had the same treatment followed by 30 days of housing in individual cages, and rats that spent either 30 or 60 days in individual cages. The superenriched environment consisted of two large toy-filled cages, one containing water and one containing food, which were attached to opposite ends of a maze in which the pattern of barriers was changed daily. Aspinous stellate neurons of layer IV and pyramidal neurons of layer III both exhibited increases in total dendritic length and number of branches in response to superenriched environment exposure. In a factorial analysis of initial experience condition by age of subject, the consistent presence of experience effects combined with the relatively rare appearance of either age effects or interactions indicated that the dominant result was for the dendritic effects of the initial superenriched environment exposure to persist through the subsequent period of individual housing.

Animals↗

PubMed2000

Dynamic regulation of the siphon withdrawal reflex of Aplysia californica in response to changes in the ambient tactile environment.

The state of an animal's environment can be viewed as a source of information that can be used to regulate both ongoing and future behavior. The present work examined how the ambient environment can regulate the Aplysia siphon withdrawal reflex (SWR) by changing the environment between calm and turbulent. Results indicate that the SWR is dynamically regulated on the basis of variations in external conditions, so that responsiveness (measured as both reflex duration and threshold) is matched to the state of the environment. Prior exposure to a noxious stimulus (tailshock) has selective effects on this regulation, suggesting the existence of multiple regulatory mechanisms. Further, neurophysiological correlates to behavioral observations were measured in sensory and motor neurons. This will allow for a detailed cellular analysis of environmental information-processing in this system.

Animals↗

PubMed1988

Genotype-environment interaction in personality development: identical twins reared apart.

The focus of this study is to identify specific genotype-environment (GE) interactions as they contribute to individual differences in personality in later life. In behavioral genetics, GE interaction refers to the possibility that individuals of different genotypes may respond differently to specific environments. A sample of 99 pairs of identical twins reared apart, whose average age is 59 years, has been studied as part of the Swedish Adoption/Twin Study of Aging (SATSA). Hierarchical multiple regression was used to detect interactions between personality and environmental measures after the main effects of genotype and environment were removed. Analyses yield evidence for 11 significant interactions that provide the first evidence for GE interaction in human development using specific environmental measures. Thus, in addition to the main-effect contributions of heredity and environment, GE interactions contribute to individual differences in personality as measured in the second half of the life course.

Adoption↗

PubMed2006

Self-esteem, academic self-concept, and achievement: how the learning environment moderates the dynamics of self-concept.

The authors examine the directionality of effects between global self-esteem, domain-specific academic self-concepts, and academic achievement. Special emphasis is placed on learning environments as potential moderators of the direction of these effects. According to the meritocracy principle presented here, so-called bottom-up effects (i.e., self-esteem is influenced by academic self-concept) are more pronounced in meritocratic learning environments than in ego-protective learning environments. This hypothesis was examined using a three-wave cross-lagged panel design with a large sample of 7th graders from East and West Germany, a total of 5,648 students who were tested shortly after German reunification. Reciprocal effects were found between self-esteem, academic self-concept, and academic achievement. In conformance with the meritocracy principle, support for bottom-up effects was stronger in the meritocratic learning environment.

Adolescent↗

PubMed2005

The formation of cognitive maps of adjacent environments: evidence from the head direction cell system.

In 2 experiments the authors tested whether the head direction (HD) cell system underlies a sense of direction maintained across environments. In Experiment 1, HD neurons failed to maintain their firing directions across T mazes in adjacent environments but rather reoriented to the T maze within each environment. Such reorientation suggests that familiar landmarks override an internal directional sense, so in Experiment 2 the authors recorded HD neurons as rats walked between novel and familiar "rooms" of a 4-chamber apparatus. In novel rooms, HD neurons maintained the firing direction of the preceding environment. However, in familiar rooms, HD neuron firing directions shifted to agree with the landmarks therein. With repeated experience, a homogeneous representation of all rooms developed in a subset of the rats.

Action Potentials↗

PubMed1999

Impact of environment on adolescent mental health and behavior: structural equation modeling.

This study uses structural equation models to describe how objective neighborhood, perceived neighborhood, and environmental support predict mental health; 792 adolescents responded to highly structured interviews. The effect of objective environment on mental health was mediated through its influence on perceived neighborhood. Environmental support mitigated negative perceptions of environment and the effect of perceived environment on mental health, while exposure to violence augmented the negative effect of perceived environment.

Adolescent↗

PubMed1975

Genetic differences between the Chinese and European races of the common carp.I. Analysis of genotype-environment interactions for growth rate.

Growth rate of 12 groups of common carp was measured at five experimental environments. Three of the 12 tested groups were strains of the domesticated European race of the common carp, one group was a representative of the Big-Belly Chinese race, and the remaining eight groups were F1 crossbreds among the European strains and between the European and the Chinese races. The average growth rate over the five environments of the Chinese Big-Belly was considerably poorer than that of the European carp. All the inter-race crossbreds and the crossbreds among the European strains showed heterosis. When the genotype-environment interaction was presented as a linear function of the quality of the environment, the regression coefficient (the overall responsiveness parameter) assumed relatively low values in the Big-Belly and two to two-and-a-half fold higher values in the European carp. The overall responsiveness of crossbreds was, on the average, intermediate between the two parents. When, however, it was partitioned into a scale function of the average genotype and specific independent responsiveness, the two components showed a high degree of heterosis but in opposite directions. An explanation of this genetic system in terms of adaptive evolution to the diverse modes of carp domestication in Europe and China was given.

Animals↗

PubMed2006

Body mass index gain, fast food, and physical activity: effects of shared environments over time.

OBJECTIVE: The magnitude of environmental vs. genetic effects on BMI, diet, and physical activity (PA) is widely debated. We followed a sibling cohort (where individuals shared households in childhood and adolescence) to young adulthood (when some continued sharing households and others lived apart) to examine the role of discordant environments in adult twins' divergent trends in BMI and health behaviors and to quantify the variation in BMI and behavior among all siblings that is attributable to environmental and additive genetic effects. RESEARCH METHODS AND PROCEDURES: In the National Longitudinal Study of Adolescent Health, siblings sharing households for > or =10 years as adolescents (mean age = 16.5 +/- 1.7 years; N = 5524) were followed into adulthood (mean = 22.4 +/- 1.8 years; N = 4368), self-reporting PA, sedentary behavior, and dietary characteristics. Adult BMI and adolescent z scores were derived from measured height and weight. RESULTS: Compared with those living together, twins living apart exhibited greater discordance in change in BMI, PA, and fast food intake from adolescence to adulthood. Adolescent household environments accounted for 8% to 10% of variation in adolescent fast food intake and sedentary behaviors and 50% of variation in adolescent overweight. Adolescent household effects on PA were substantially greater in young adulthood (accounting for 50% of variation) vs. adolescence. Young adult fast food intake was significantly affected by young adult household environment, accounting for 12% of variation. DISCUSSION: These findings highlight important environmental influences on BMI, PA, and fast food intake during the transition to adulthood. Household and physical environments play an important role in establishing long-term behavior patterns.

Adolescent↗

PubMed2006

Characterization of the rapid-onset type of behavioral sensitization to amphetamine in mice: role of drug-environment conditioning.

A rapid-onset type of behavioral sensitization (ROBS) has been demonstrated in rats treated with a single 'priming' injection of amphetamine (AMP). In that species, however, this phenomenon was restricted to AMP-induced stereotyped behavior (SB), not occurring for the locomotor-stimulant effect (LSE) of AMP and not reflecting environment-specific sensitization. In the present study, the ROBS was characterized in the mouse. Mice received a single 'priming' intraperitoneal injection of 5.0 mg/kg AMP which was paired or not with environment. At different intervals (3, 4 or 5 h) subgroups were tested for AMP (1.5 or 5.0 mg/kg)-induced SB or AMP (1.5 mg/kg)-induced open-field LSE. Results showed that: (1) in the absence of drug-environment association, a priming injection of AMP increased the SB induced by a 1.5 mg/kg AMP challenge injection given 3 h (but not 4 or 5 h) later; (2) when the dose of AMP challenge injection was increased to 5.0 mg/kg, an enhancement of SB was verified at all the intervals tested (3, 4, and 5 h); (3) when animals were tested in an open field, the priming injection of AMP produced an increase in the LSE of a 1.5 mg/kg AMP challenge injection, given 4 h later; (4) drug-environment association increased both SB and locomotion after a saline challenge injection and potentiated the rapid-onset sensitization of both behaviors in AMP-challenged mice. Collectively, these results demonstrate that the ROBS phenomenon also occurs in mice, is extended to AMP-induced LSE, and is markedly potentiated by (but does not depend on) environmental conditioning.

Amphetamine↗

PubMed1998

Reaction norm functions and QTL-environment interactions for flowering time in Arabidopsis thaliana.

Many plant traits are phenotypically plastic in response to resource levels that vary continuously among environments. To be able to predict phenotypes in new environments, it is useful to model reaction norms as functions, rather than as a collection of discrete character states. Flowering date and rosette leaf number were measured in 100 recombinant inbred lines of Arabidopsis thaliana, grown on a gradient of light intensity. The results show that there is genetic variation among the recombinant inbred lines for parameters of the reaction norm functions. Genetic variances for leaf number and flowering date are highest under low light conditions. Underlying quantitative trait loci (QTLs) affecting the shape of the reaction norm functions were mapped by modifying Haley & Knott (1992) regressions to include polynomial effects of the environment. Quantitative trait loci of large effect were generally insensitive to the resource gradient. Seven QTLs affecting flowering date and eight QTLs for rosette leaf number were identified, of which only two had significant effects on the linear and quadratic components of the reaction norm function. These results suggest that the genotype-environment interactions for flowering time are controlled by many minor genes, whose effects are below the detection limit in most mapping experiments.

Arabidopsis↗