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PubMed2003

Increase of atmospheric CO2: response patterns of a simple terrestrial man-made ecosystem.

Simple models of terrestrial ecosystems with a limited number of components are an efficient tool to study the main laws of functioning of populations, including microbial ones, and their communities, as components of natural ecosystems, under variable environmental conditions. Among other factors are the increase of carbon dioxide in the atmosphere and limitation of plants' growth by biogenic elements. The main types of ecosystems' responses to changes in environmental conditions (a change in CO2 concentration) have been demonstrated in a "plants-rhizospheric microorganisms-artificial soil" simple experimental system. The mathematical model of interactions between plants and microorganisms under normal and elevated atmospheric CO2 and limitation by nutrients (nitrogen and phosphorus) yielded a qualitative agreement between calculated and experimental values of limiting substances concentrations and release rates of exudates.

Atmosphere↗

PubMed1999

Sealed environment chamber for canopy light interception and trace hydrocarbon analyses.

Two sealed chambers were constructed, each measuring approximately 4.5 m x 3 m x 2.5 m (LxWxH). Heat exchangers and air handling components were integrated within the sealed environment. Construction materials were chosen to minimize off-gassing and oxidation. Acceptable materials included stainless steel, Teflon (TM), glass and Heresite (TM) or baked enamel coated metal parts. The glass-topped chambers have externally mounted microwave powered light sources providing minimum PAR at canopy level of 1000 micrometers m-2 s-1. Major gases (CO2, O2) were monitored. Other environmental variables relevant to plant production (humidity, temperature, nutrient solution) were monitored and controlled continuously. Typical environment control capability and system specifications are presented. The facility is described as a venue ideally suited to address specific research objectives in plant canopy light interception, such as the roles of novel microwave powered overhead and inner-canopy light sources for dense plant canopies. In addition, control of recycled hydroponic nutrient solutions and analysis of trace atmospheric hydrocarbons in the context of sealed environment life support can be concurrently monitored.

Air Conditioning↗

PubMed2002

Does migration exaggerate the relationship between deprivation and limiting long-term illness? A Scottish analysis.

Few epidemiological studies of the links between health and environmental variables account for the potentially confounding effects of population migration. Here we explore the relationship between self-reported limiting long-term illness and material deprivation, using individual-level 1991 census data extracted for Scotland. The aim is to investigate whether the migration patterns of ill individuals influences the relationship between limiting long-term illness and material deprivation. Specifically, we seek to determine whether individuals who are well are more likely to migrate away from deprived areas and whether ill individuals are more likely to migrate towards deprived areas. If true, this would suggest that the apparent relationship between deprivation and limiting long-term illness is exaggerated by the effects of migration. We then examine the issue controlling for individual-level characteristics expected to influence limiting long-term illness and pay special attention to the role of public housing in these relationships.

Adolescent↗

PubMed1997

Population density and spatial differentials in child mortality in Zimbabwe.

Large regional variations in under-five mortality exist within many sub-Saharan countries. Population density as a potential explanatory factor for these regional variations has seldom been considered despite it being implicated as a determinant of mortality at other spatial scales. In Zimbabwe, the "Ndebele provinces"-Matabeleland North and South-have significantly lower levels of under-five mortality than the other ("Shona") provinces. This regional differential is explored using the Zimbabwe Demographic and Health Survey and census data. Factors other than population density that may contribute to the differential are examined. After controlling for the effects of potentially confounding socio-economic, demographic and environmental variables using Cox regression models children aged 1-4 yr living in the Ndebele provinces continued to have a level of mortality 45% lower than their counterparts in the Shona provinces. The possibility that regional variations in health care provision and/or cultural factors contribute to the mortality differential is also examined and rejected. Population densities in the Ndebele provinces are of a far lower order than in the Shona provinces. The main causes of child mortality in Zimbabwe in the time period under consideration were diarrhoea, ALRI, measles and malaria. How population density may affect the transmission of these infections and, hence, mortality is discussed. It is suggested that population density may provide an explanation for the spatial variation in child mortality in Zimbabwe. The implications of changing population densities for child health in urban and rural sub-Saharan Africa are briefly considered.

Cause of Death↗

PubMed1998

Putting risk in its place: methodological considerations for investigating extreme event health risk.

Health is affected by the places in which people live, work and interact, yet many epidemiological studies overlook the characteristics of places and instead focus solely on the people who inhabit them. Place-based investigations of disparities in health outcomes are concerned with the healthiness of places and not merely the healthiness of the populations in these places. A place-based approach has been used within medical geography and medical sociology, typically in the study of health differentials associated with long-term, cumulative exposures to a wide range of environmental variables. This approach has rarely been extended, however, to health research that looks at the effects of extreme events (such as industrial accidents or hurricanes). The purpose of this paper is to incorporate a place-based framework into extreme event health research. The paper first discusses methodological considerations for a place-based approach and then illustrates the use of spatial analysis techniques as the first step in identifying place-based risk factors in mortality associated with heat waves. The study centers on St. Louis, Missouri, a city where heat waves are frequent and heat-related mortality is high. The results show that heat-related mortality rates during the most severe heat waves were generally higher in the warmer, less stable and more disadvantaged areas of St. Louis and lower in the cooler and more affluent parts of the city. During the milder years analyzed, there was little evidence of a relationship between place-based characteristics and the distribution of heat-related mortality. These findings about extreme event mortality risk would not have been evident from a population-based analysis. Ongoing dialog between epidemiologists and social scientists can help to bring place into the arena of extreme event research and to increase understanding of the role of place in risk.

Health Status Indicators↗

PubMed2002

Cognitions, coping and social environment predict adjustment to phantom limb pain.

Biopsychosocial models of chronic pain hypothesize a role for psychological and environmental factors in adjustment to chronic pain. To test the utility of such models for understanding phantom limb pain, 61 persons with recent amputations were administered measures of average phantom limb pain intensity, pain interference, depression, pain coping use, pain cognitions and appraisals, and social environmental variables 1 month post-amputation, and the measures of pain intensity, pain interference, and depression again 5 months later. Multiple regression analyses showed that the psychosocial predictors made a statistically significant contribution to the concurrent prediction of average phantom limb pain, pain interference, and depression at the initial assessment, and a significant contribution to the prediction of subsequent change in pain interference and depression over the course of 5 months. The results support the utility of studying phantom limb pain from a biopsychosocial perspective, and identify specific biopsychosocial factors (e.g., catastrophizing cognitions, social support, solicitous responses from family members, and resting as a coping response) that may play an important role in adjustment to phantom limb pain.

Adaptation, Psychological↗

PubMed1998

Comparative analysis of two methods used to show interspecific associations in naturally acquired parasite nematode communities from the abomasum of ewes.

The aim of our study was to compare a multivariate and a univariate method to evaluate the associations between nematode species in natural infections. We used a data set based on the 3-year study of the community of abomasal nematodes in ewes of the middle-Atlas region of Morocco. Frequency data (percentage of each species in the individual host community) were processed by principal component analysis. Euclidean distances between species (D2) were calculated from projections of principal component analysis on three axes and compared to a bivariate estimate (1 - correlation coefficient R). Low distances were recorded between morphs of the same species (Teladorsagia circumcincta and T. trifurcata, for example), which indicates a positive association. Only two species, Trichostrongylus axei and T. circumcincta, were negatively associated having D2 values much over 1. The distances D2, i.e., multivariate measure of association intensity were similar in most cases to 1- R estimates, indicating probably the absence of strong multispecies association. The D2 fitted a Motomura geometric progression model indicating that associations were arranged in a continuum from low to high values, but they did not depart much from what could be expected from random associations for most species. The D2 interest is mostly to relate associations with environmental variables, and comparing with 1 - R, to assess the degree of interaction in the community.

Abomasum↗

PubMed2000

Cloning and primary structure of putative cytosolic and mitochondrial malate dehydrogenase from the mollusc Nucella lapillus (L.).

The evolutionary history of the malate dehydrogenase (MDH) gene family [NAD-dependent MDH; EC 1.1.1.37 and NAD(P)-dependent MDH; EC 1.1.1.82] has received much attention. MDHs have also featured extensively as electrophoretic markers in population genetics and evolutionary ecology, and in many cases, intraspecific variation in MDH has been correlated with environmental variables. However, while the amino acid residues essential for MDH function are known, no studies have examined intraspecific nucleotide variation despite evidence indicating that natural selection may be operating on this locus. This study presents two sets of degenerate oligonucleotide PCR primers to facilitate the cloning of cytosolic MDH (cMDH) and mitochondrial MDH (mMDH) from a broad range of animals (cMDH) and animals and plants (mMDH). These primers were used to obtain putative cMDH and mMDH cDNAs from the mollusc Nucella lapillus. The N. lapillus cMDH cDNA was found to encode a putative cMDH protein of 334aa and 36kDa, while the mMDH cDNA encoded a putative mature mMDH protein of 315aa and 33kDa. The putative amino acid sequences of the two compartmentalised N. lapillus MDHs are presented and compared to other known MDH sequences.

Amino Acid Sequence↗

PubMed1996

The molecular genetics of type-4 fimbriae in Pseudomonas aeruginosa--a review.

Type-4 fimbriae (or pili) are filaments found at the poles of a wide range of bacterial pathogens, including Neisseria gonorrhoeae, Moraxella bovis, Dichelobacter nodosus and Pseudomonas aeruginosa. They are composed of a small subunit which is highly conserved among different species and appear to mediate adhesion and translocation across epithelial surfaces via a phenomenon termed "twitching motility'. These fimbriae are key host colonisation factors and important protective antigens. We have analysed the genetics and biosynthesis of type-4 fimbriae in P. aeruginosa, which is an opportunistic pathogen of compromised individuals, including those suffering cystic fibrosis, AIDS or burns. A library of P. aeruginosa transposon mutants was constructed which exhibited loss of twitching motility, as determined by altered colony morphology. Analysis of these mutants, and of similar collections by other groups, have revealed that there are at least 22 genes involved in type-4 fimbrial assembly and function. A large number (pilA, B, C, D, E, M, N, O, P, Q, T, U, V and Z) appear to be involved in the biogenesis of the fimbriae and to represent a subset of a supersystem involved in the assembly of surface-associated protein complexes. Homologs of at least some of these genes have subsequently been identified in other type-4 fimbriate bacteria. In P. aeruginosa, the system is also regulated via two signal transduction pathways-a classic sensor-regulator system (encoded by pilS, pilR and rpoN) which controls transcription of the fimbrial subunit, presumably in response to host cues, and a chemotactic system (encoded by pilG, H, I, J, K and L) which may be involved in the directional or rate control of twitching motility in response to local environmental variables.

Bacterial Proteins↗

PubMed1999

Effects of tailored, personalized and general health messages on physical activity.

Physical inactivity is a major public health problem. Patient education programs and materials that are customized to address the unique needs and concerns of specific patients have shown promise in changing a range of health related behavior, although findings to date for physical activity have been equivocal. In this study a randomized controlled trial was conducted among 272 adult primary care patients to compare the effectiveness of tailored, personalized and general health messages, and usual medical care in promoting leisure time physical activity (LTA) and physical activities of daily living (PADLs). Patients in the tailored group were more likely to increase PADLs than were patients in the personalized, general and control groups (65% vs. 46% vs. 56% vs. 54%) and less likely to being doing fewer PADLs at follow-up (18% vs. 38% vs. 38% vs. 38%; chi 2 = 12.2, df = 6, p = 0.056). There were no significant differences for LTAs. To help maximize the effectiveness of future tailored interventions on physical activity, studies should seek to identify the social, psychological and environmental variables that are most important to include in tailored materials.

Activities of Daily Living↗

PubMed2000

Extraversion. Interaction between D2 dopamine receptor polymorphisms and parental alcoholism.

Both molecular genetic factors (the D2 dopamine receptor (DRD2) and the D4 dopamine receptor (DRD4) polymorphisms) and environmental influences of living in an alcoholic or nonalcoholic home on the personality traits of Extraversion and Neuroticism were assessed in drug-naive, young adolescent boys. There were no significant main effects of genetic or environmental factors on either Neuroticism or Extraversion as measured by the Junior Eysenck Personality Inventory (JEPI). However, a significant interaction between DRD2 (but not DRD4) alleles and environmental variables was observed on Extraversion. Specifically, children with the minor alleles of the DRD2 gene showed a significantly greater Extraversion score when living in an alcoholic than in a nonalcoholic home. In contrast, children with the major alleles of the DRD2 gene showed a trend in the opposite direction. Although the results are preliminary and pending replication, they nevertheless provide the first report of a specific gene-environment interaction involving a human personality trait.

Adolescent↗

PubMed1998

Regulation of appetite and body weight in seasonal mammals.

As models of physiological regulation of body weight, adiposity and appetite, seasonal mammals offer unique opportunities for manipulating fundamental regulatory processes that may not be available in the more frequently-studied laboratory rodents. Seasonal weight and intake cycles are anticipatory rather than reactive in nature, being manifest despite the availability of adlibitum supplies of food. They are exhibited despite all other environmental variables being held constant, and are reversible. Appropriate body weight appears to be a sliding set point in many seasonal mammals, which can move in either direction, largely independently of age. While few data are available other than from rats and mice, there appears to be a strong commonality of central neuroendocrine and peripheral signalling systems between seasonal and non-seasonal mammals, although the conditions under which endogenous regulatory pathways are activated may differ significantly between species. Peripheral and central signalling systems implicated in the regulation of appetite and body weight may be modulated during seasonal transitions. Discussion will concentrate on hypothalamic neuropeptides, gastrointestinal satiety peptides, the recently-described peptide, leptin, that is secreted by adipose tissue, and the interactions between these regulatory components.

Animals↗

PubMed2002

The association between urban form and physical activity in U.S. adults.

BACKGROUND: Physical inactivity is associated with multiple adverse health outcomes. Results from the transportation literature suggest that aspects of the urban environment may influence walking for transportation. In this paper we examine the association between a proxy measure of the urban environment and walking behavior. METHODS: We analyzed the association between home age and walking behavior in U.S. adults using data from the Third National Health and Nutrition Examination Survey. Logistic regression was used to estimate odds ratios and 95% confidence intervals and to control for the effects of gender, race/ethnicity, age, education level, household income, and activity limitations. RESULTS: Adults who lived in homes built before 1946 and from 1946 to 1973 were significantly more likely to walk 1+ miles > or =20 times per month than those who lived in homes built after 1973. This association was present among people living in urban and suburban counties, but absent among those living in rural counties. The association was also found in models that controlled for gender, race/ethnicity, age, education, income, and any health-related activity limitation. Other forms of leisure-time physical activity were not independently associated with home age. CONCLUSIONS: These results support the hypothesis that environmental variables influence walking frequency and suggest that home age may be a useful proxy for features of the urban environment that influence physical activity in the form of walking. Such proxy measures could facilitate testing ecologic models of health behavior using survey data.

Adult↗

PubMed1999

Tailored advice on exercise--does it make a difference?

OBJECTIVE: A controlled trial to compare the effectiveness of verbal advice from a family physician (FP) combined with either "standard" or "tailored" written information on physical activity in increasing the levels of physical activity in sedentary patients. DESIGN: Sedentary patients (n = 763) were recruited through ten family practices and allocated to a control group or one of two intervention groups. Brief advice on physical activity was given by the FP during the consultation and either a standard or tailored pamphlet was mailed to the home address of patients assigned to the intervention groups within two days of their visit to the FP. RESULTS: The response to follow-up, via a postal survey at one, six, and twelve months after the index consultation was 70%, 60%, and 57%, respectively. Treating all nonresponders as sedentary, the results revealed that although more tailored subjects reported some physical activity at each follow-up compared with the standard group, these differences were not significant. Furthermore, there was no significant difference in movement across the stages of readiness to exercise at follow-up between subjects in the tailored group who received material targeting their current stage (precontemplation or contemplation) and the standard group who received generic material that addressed both stages. CONCLUSION: These findings do not concur with the results from previous research in the areas of nutrition and smoking cessation where additional benefits were seen with a tailored intervention. Future research on the application of the principles of "tailoring" to the promotion of physical activity should focus on identifying which, if any, physical, social, psychological or environmental variables should be addressed to produce improved outcomes over and above the effects of well designed generic materials.

Adolescent↗

PubMed2001

The week, inherited in neonatal human twins, found also in geomagnetic pulsations in isolated Antarctica.

About 7-day (circaseptan) components, found at different levels of organization, notably in relation to growth, regeneration, repair and development, are often viewed as reflecting no more than the 7-day societal schedule, ample evidence for a built-in feature notwithstanding. Herein, we resolve circaseptans in geomagnetic pulsations recorded by a stand-alone magnetometer residing in Antarctica, far away from societal influences. Human physiological data, collected in the neonatal intensive care unit, show by intra-class correlation analysis that the nonlinearly assessed circaseptan period of heart rate, diastolic blood pressure and body weight is more similar between same-gender twins than among twin pairs, lending additional support for the endogenicity of circaseptans. Like circadians, about-weekly features in environmental variables such as geomagnetic pulsations were genetically acquired in the course of evolution.

Activity Cycles↗

PubMed1997

[Opinions and behaviors of French adolescents confronted with tobacco in 1995].

BACKGROUND: The French Committee for Health Education has observed the adolescent's opinions and behaviours on smoking since 1977. POPULATION AND METHODS: The surveys were carried out on a representative sample, made up by quotas method, of the population concerned (12 to 18 years old). The last data (1995) were analyzed in order to evaluate present smoking behaviour and to measure the influence of the social environment. RESULTS: In 1995 more than one out of three (35.1%) young people smoked at least once in a while; this smoking prevalence was nearly the same among boys (34.7%) as among girls (35.5%). Since 1977, the long-term trend of the rates showed a decrease and the monitoring of the starting age proved that adolescents began to smoke more and more later. The influence of peer and parents smoking was strong. The socioeconomic status of the family and also the amount of pocket money were other determinants of smoking. The family and school atmosphere played an important role as well. CONCLUSIONS: The influence of all these environmental variables on the young person's smoking behaviour underlines the necessity of developing simultaneously campaigns aimed at young people and actions among different populations. The emergence of a positive status for the non-smoker supports the choice of the strategies for the latest campaigns.

Adolescent↗

PubMed2002

The 70-kDa heat shock protein response in two intertidal sculpins, Oligocottus maculosus and O. snyderi: relationship of hsp70 and thermal tolerance.

The role that hsp70 plays in influencing thermal tolerance of a whole animal is not clearly understood. We explored this question by examining liver hsp70 response in the tidepool sculpin (Oligocottus maculosus) and fluffy sculpin (O. snyderi), which have distinct distribution patterns in the intertidal zone. The tidepool sculpin is in upper and lower tidepools, while the fluffy sculpin is exclusively in lower tidepools during a low tide. We conducted experiments in order to investigate: (1) habitat water temperatures; (2) upper thermal tolerance limits; (3) the cellular hsp70 response to changes in water temperature in nature; (4) induction temperatures for hepatic hsp70 and hsp70 mRNA; and (5) effects of long-term heat stress on liver hsp70 levels, in these sculpins. Accordingly, we found: (1) the tidepool sculpin was exposed to a wider temperature range in nature; (2) the tidepool sculpin had higher lethal and induction temperatures for hsp70; (3) the liver hsp70 level of the tidepool sculpin was less sensitive to changes in water temperatures; and (4) the tidepool sculpin had higher constitutive hsp70 levels in nature, compared with the fluffy sculpin. From these results, we proposed that the less thermally sensitive tidepool sculpin may enhance its thermal tolerance by having a large pool of cellular hsp70, thus allowing it to inhabit the upper intertidal zone with relatively large and unpredictable fluctuations in environmental variables.

Adaptation, Physiological↗

PubMed2003

Testing evolutionary hypotheses about human biological adaptation using cross-cultural comparison.

Physiological data from a range of human populations living in different environments can provide valuable information for testing evolutionary hypotheses about human adaptation. By taking into account the effects of population history, phylogenetic comparative methods can help us determine whether variation results from selection due to particular environmental variables. These selective forces could even be due to cultural traits-which means that gene-culture co-evolution may be occurring. In this paper, we outline two examples of the use of these approaches to test adaptive hypotheses that explain global variation in two physiological traits: the first is lactose digestion capacity in adults, and the second is population sex-ratio at birth. We show that lower than average sex ratio at birth is associated with high fertility, and argue that global variation in sex ratio at birth has evolved as a response to the high physiological costs of producing boys in high fertility populations.

Adaptation, Physiological↗