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PubMed2006

Algal-bacterial interactions in metal contaminated floodplain sediments.

The aim of the present study was to investigate algal-bacterial interactions in a gradient of metal contaminated natural sediments. By means of multivariate techniques, we related the genetic structure (denaturing gradient gel electrophoresis, DGGE) and the physiological structure (community-level physiological profiling, CLPP) of the bacterial communities to the species composition of the algal communities and to the abiotic environmental variables, including metal contamination. The results revealed that genetic and physiological structure of the bacterial communities correlated with the species composition of the algal community, but hardly to the level of metal pollution. This must be interpreted as an indication for a strong and species-specific linkage of algal and bacterial species in floodplain sediments. Metals were, however, not proven to affect either the algal or the bacterial communities of the Dutch river floodplains.

Bacteria↗
PubMed2006

Development and application of a laboratory flux measurement system (LFMS) for the investigation of the kinetics of mercury emissions from soils.

Recent measurements at different locations suggest that the emission of mercury from soils may play a more pronounced role in the global mercury cycle as suggested by global emission inventories and global mercury cycling models. For up scaling and modelling of mercury emissions from soils a comprehensive assessment of the processes controlling the emission of mercury from soils is imperative. We have developed a laboratory flux measurement system (LFMS) to study the effect of major environmental variables on the emission of mercury under controlled conditions. We have investigated the effects of turbulent mixing, soil temperature and solar radiation on the emission of mercury from soils. The emission of mercury from soils is constant over time under constant experimental conditions. The response of the mercury emission flux to variations of the atmospheric transfer parameters such as turbulence requires a rapid adjustment of the equilibrium that controls the Hg(o) concentration in the soil air. It has been shown that the light-induced flux is independent of the soil temperature and shows a strong spectral response to UV-B.

Computer Simulation↗
PubMed2006

The ecological quality status of the Bay of Seine and the Seine estuary: use of biotic indices.

Using recent indices developed, in part, for use under the European Water Framework Directive (AMBI, BENTIX, BOPA, BQI, I2EC and the trophic index ITI), the ecological quality status of two highly contaminated environments--the Bay of Seine and the Seine estuary (Eastern English Channel)--was determined on several spatial and temporal scales. Data from 604 observations gathered over a 14-year period (1988-2002) were analyzed, and the results used to show the relationship between biotic indices, environmental variables and classic descriptors (e.g., number of species, total abundance, dominance index, ES(50) and Shannon/Brillouin diversities). Though the specific ecological quality (EcoQ) values calculated with the various indices were different, the overall trend of the results was similar. Synthesizing the values produced by the six indices used in the study allowed attribution of a high to good EcoQ status to the Bay of Seine and a moderate EcoQ to the estuary. The mesh size used when processing samples was proved to have no effect in winter on the EcoQ values for either body of water.

Animals↗
PubMed1986

A genetic-epidemiologic study of human immune responsiveness to allergens in an industrial population. III. Environmental influences on skin sensitivity and total serum IgE in a stratified random sample.

We quantitated puncture skin-test responses to 6 standardized, high-quality-inhalant allergen extracts in 320 adults - a stratified random sample, equally distributed between the sexes and among all decades between 20 and 60 years. For each subject, the 'average' IgE-mediated skin sensitivity to the entire panel of allergens (Allergy Index) was calculated. We evaluated correlations between log[total serum IgE]levels and Allergy Index versus quantitative measures of several environmental variables, including infection in childhood, residential history and smoking history. Age, sex and month bled were also included in these analyses. Although many significant intercorrelations were found among these variables, subsequent analyses by stepwise multiple regression showed that log[total IgE], age and smoking history were the best predictors of the Allergy Index and that the Allergy Index and sex were the best predictors of log[total IgE]. The negative relationship between smoking and skin-test responsiveness may reflect a tendency for allergic people to avoid the irritative effects of smoking on respiration. Our analyses, which simultaneously evaluated the effects of age, sex, Allergy Index and smoking history on log[total IgE]levels, did not support other studies which concluded that smoking significantly increases total serum IgE levels.

Adult↗
PubMed2002

Effects of extremely hot days on people older than 65 years in Seville (Spain) from 1986 to 1997.

The effects of heat waves on the population have been described by different authors and a consistent relationship between mortality and temperature has been found, especially in elderly subjects. The present paper studies this effect in Seville, a city in the south of Spain, known for its climate of mild winters and hot summers, when the temperature frequently exceeds 40 degrees C. This study focuses on the summer months (June to September) for the years from 1986 to 1997. The relationships between total daily mortality and different specific causes for persons older than 65 and 75 years, of each gender, were analysed. Maximum daily temperature and relative humidity at 7.00 a.m. were introduced as environmental variables. The possible confounding effect of different atmospheric pollutants, particularly ozone, were considered. The methodology employed was time series analysis using Box-Jenkins models with exogenous variables. On the basis of dispersion diagrams, we defined extremely hot days as those when the maximum daily temperature surpassed 41 degrees C. The ARIMA model clearly shows the relationship between temperature and mortality. Mortality for all causes increased up to 51% above the average in the group over 75 years for each degree Celsius beyond 41 degrees C. The effect is more noticeable for cardiovascular than for respiratory diseases, and more in women than in men. Among the atmospheric pollutants, a relation was found between mortality and concentrations of ozone, especially for men older than 75.

Aged↗
PubMed2006

Influence of maternal mass and condition on energy transfer in Weddell seals.

1. Environmental variation influences food abundance and availability, which is reflected in the reproductive success of top predators. We examined maternal expenditure, offspring mass and condition for Weddell seals in 2 years when individuals exhibited marked differences in these traits. 2. For females weighing > or = 355 kg there was a positive relationship between maternal post-partum mass (MPPM) and lactation length, but below this there was no relationship, suggesting that heavier females were able to increase lactation length but lighter females were restricted to a minimum lactation period of 33 days. 3. Overall, females were heavier in 2002, but in 2003 shorter females were lighter than similar-sized females in 2002 suggesting that the effects of environmental variability on foraging success and condition are more pronounced in smaller individuals. 4. There was no relationship between MPPM and pup birth mass, indicating pre-partum investment did not differ between years. However, there was a positive relationship between MPPM and pup mass gain. Mass and energy transfer efficiency were 10.2 and 5.4% higher in 2002 than 2003, which suggests costs associated with a putatively poor-resource year were delayed until lactation. 5. Heavier females lost a higher proportion of mass during lactation in both years, so smaller females may not have been able to provide more to their offspring to wean a pup of similar size to larger females. 6. MPPM had only a small influence on total body lipid; therefore, regardless of mass, females had the same relative body composition. Females with male pups lost a higher percentage of lipid than those with female pups, but by the end of lactation female pups had 4.5% higher lipid content than males. 7. It appears that for Weddell seals the consequences of environmentally induced variation in food availability are manifested in differences in maternal mass and expenditure during lactation. These differences translate to changes in pup mass and condition at weaning with potential consequences for future survival and recruitment.

Animals↗
PubMed2005

Factors associated with control of type I diabetes in Malaysian adolescents and young adults.

OBJECTIVES: To examine the association between ethnicity, depression, quality of life, and diabetic control in Malaysian adolescents and young adults with type I diabetes mellitus. METHODS: Fifty-two outpatients with type I diabetes (mean age 15.5 years) who attended a Diabetes Clinic were included. The level of HbA1c was the measure of diabetes control used (better control defined as HbA1c < 10%). Other variables were measured through questionnaires (e.g., depressive symptoms, quality of life), computerized diagnostic interviews (major depression), and medical records (e.g., demographic, family circumstances, compliance with treatment). RESULTS: Ethnic Chinese youth showed better diabetic control than Malays and Indians (mean HbA1c 9.1%, 10.3%, and 11.0% respectively). Young people with better diabetic control (HbA1c < 10%) were more likely to have better quality of life and less likely to live in problematic families. When the cut-off for diabetic control was stricter (HbA1c < or = 8%), the young person's compliance was the main predictor of poor control. Family problems were also associated with poor control but to a lesser extent. The initial association between poorer diabetes control and depression became non-significant when quality of life was taken into account. CONCLUSIONS: There are ethnic differences in juvenile diabetic control in this Malaysian sample which need to be understood further. Previous findings of an association between quality of life and glycemic control were verified but different definitions of good control showed different associations with individual and environmental variables. Clinicians' awareness and early intervention for psychosocial problems (for example, inadequate family support) could improve diabetes control.

Adolescent↗
PubMed2004

Manganese levels during pregnancy and at birth: relation to environmental factors and smoking in a Southwest Quebec population.

Manganese (Mn) is both an essential element and a potent neurotoxin. Higher demand during pregnancy leads to increased blood levels. Previous studies have suggested that environmental factors may influence blood Mn levels. As part of a community-based survey of potentially toxic environmental contaminants among pregnant women, the objective of this exploratory study was to examine the Mn status in pregnant women and their newborns with respect to sociodemographic and environmental variables. Pregnant women from Southwest Quebec were recruited in the first or second trimester through the public health prenatal program Mn was analyzed in mother's blood at entry into the study, in the second trimester (for those who entered during the first trimester), and at delivery, as well as in umbilical cord blood and in placental tissue. Sociodemographic data and information about pregnancy were obtained by two questionnaires; the first was administered at study entry and the second a few weeks following birth. Results showed that mothers' Mn blood levels increased significantly during pregnancy and cord blood Mn levels were significantly higher than those for mothers' blood. There was no relation to age. Smokers had significantly lower Mn blood levels compared to nonsmokers at the second trimester. Those who lived in urban and/or agricultural areas had significantly higher levels compared to those who lived in small villages. Those who reported pesticide spraying less than 1 km from their house likewise had significantly higher levels compared to the others. These findings suggest that lifestyle and environmental factors may interfere with the delicate balance and homeostatic mechanisms required to maintain Mn at optimal levels for physiological changes during pregnancy.

Adult↗
PubMed1979

Testing a causal model of environmental influences on the early drug involvement of inner city junior high school youths.

The present study examines a causal model explaining inner city youths' drug involvement using environmental variables which previously have been investigated singly or in various combinations and shown to influence drug use: the availability of drugs in the neighborhood and at school, a view of the neighborhood as tough, the esteem given to drug using, gang-involved persons by peers, friends' substance use, and participation in drug/street culture spare-time activities. The results show friends' use of alcohol and marijuana and participation in drug/street culture out-of-school activities have strong direct effects on personal drug involvement for the Black and Puerto Rican junior high school males and females who were studied; further, friends' use of alcohol and marijuana and the status peers give to drug using, gang-involved persons have respectable indirect effects on drug involvement for the four groups. In addition to these common features, a number of differences in the factors relating to drug involvement are found in the four groups. Implications of the results for alternative methods of drug abuse prevention and treatment are discussed, as is the necessity of utilizing an environmental, sociocultural view of drug use to adequately explain youth drug taking.

Adolescent↗
PubMed1994

Placental arsenic and cadmium in relation to lipid peroxides and glutathione levels in maternal-infant pairs from a copper smelter area.

Arsenic exposure may enhance oxidative damage causing adverse health effects in pregnant women. The purposes of this paper are: (i) to evaluate placental arsenic concentration as a biomarker of arsenic exposure for pregnant women; and (ii) to examine the relationship between metal exposure from a copper smelter area in Bulgaria and oxidative damage during pregnancy (as measured by glutathione and lipid peroxides) in 49 maternal-infant pairs. Placental levels of arsenic were highest in areas with the highest environmental contamination, and environmental variables (residency, smoking and occupational exposure) explained a large portion of the observed variability in placental arsenic levels (linear regression R2 = 0.71). The combined exposures of smoking and living in the smelter area were associated with lower glutathione antioxidant protection. The per cent maternal and cord blood glutathione in reduced form was significantly lower for smokers compared to non-smokers in the smelter area (47 versus 66 per cent in maternal blood, P < 0.01, and 60 versus 75 per cent in cord blood, P < 0.05). Higher concentrations of lipid peroxides in maternal blood, cord blood and placenta, though not statistically significant, suggested that pregnant women with both exposures may be at higher risk of oxidative damage.

Adult↗
PubMed2005

APOA1/C3/A4 gene cluster variability and lipid levels in Brazilian children.

Genetic studies have suggested that polymorphisms of genes coding for apolipoproteins are significant determinants of serum lipoprotein and lipid levels in adults. However, only a few studies have investigated the association of these polymorphisms in children. Therefore, in the present investigation we studied the distribution of APOA1 -75 G>A, +83 C>T, APOC3 -482 C>T, -455 T>C and 3238 C>G, and APOA4 Q360H and T347S polymorphisms and their influence on plasma lipoprotein levels in children from a Brazilian northeastern admixed population. The seven polymorphic sites were genotyped in 414 children aged 5 to 15 years (mean 8.9 +/- 2.9). The genotypes of the seven polymorphic sites were assessed by PCR-RFLP methods. The frequencies of the less common alleles were, in general, intermediate among parental populations, as expected. Strong linkage disequilibrium was detected between polymorphisms at the APOA1, APOC3 and APOA4 loci in this admixed population sample. Overall the genotype effects seen in adults were weaker or absent in children. The APOC3/-455 and APOA4 T347S variants showed significant effects on HDL cholesterol in girls (P = 0.033 and P = 0.016, respectively). Significantly higher plasma total (P = 0.003) and LDL cholesterol (P = 0.004) levels were observed in boys who were carriers of the 3238G allele at the APOC3/3238 C>G site. These results disclosed an overall absence of associations between these polymorphisms and lipids in children. This finding is not unexpected because expression of the effect of these polymorphisms might depend on the interaction with environmental variables both internal and external to the individual.

Adolescent↗
PubMed1995

Impact of carbon and flooding on the metabolic diversity of microbial communities in soils.

The assumption that carbon and soil water content are major determinants of microbial community structure and function is rarely questioned because of substantial evidence of the impacts of these variables on specific populations and functions. The significance of carbon and water for metabolic diversity at the microbial community level was tested on the field scale in agricultural plots varying in carbon inputs and in whether they were flooded. Surface soils in which rice straw was incorporated or burned and which were flooded or unflooded were sampled at monthly intervals three times during the flooded winter period (January to March) and again 1 month postdraining. Biomass carbon and nitrogen were not affected by treatments, active bacterial counts showed slight increases, and respiration rates were increased by carbon inputs and flooding. Biolog microplates were inoculated with soil extracts to quantify the metabolic diversity of the soil microbial community. Canonical correspondence analysis and the Monte Carlo permutation testing showed that differences in substrate utilization patterns were significantly related (P < 0.001) to carbon and flooding treatments. Biolog substrates whose metabolism was altered by the treatments were consistent across dates and tended to be positively related (utilization enhancement) to carbon inputs and negatively related to winter flooding. The importance of carbon as an environmental variable increased over time after straw treatment, whereas the importance of water became evident after flooding and decreased after drainage. The effect of long-term rice straw incorporation on substrate utilization patterns at another field site was consistent with these results despite the dissimilarities of the two soils.

Journal Article↗
PubMed1997

Phylogenetic analysis of the evolution of lactose digestion in adults.

In most of the world's population the ability to digest lactose declines sharply after infancy. High lactose digestion capacity in adults is common only in populations of European and circum-Mediterranean origin and is thought to be an evolutionary adaptation to millennia of drinking milk from domestic livestock. Milk can also be consumed in a processed form, such as cheese or soured milk, which has a reduced lactose content. Two other selective pressures for drinking fresh milk with a high lactose content have been proposed: promotion of calcium uptake in high-latitude populations prone to vitamin-D deficiency and maintainance of water and electrolytes in the body in highly and environments. These three hypotheses are all supported by the geographic distribution of high lactose digestion capacity in adults. However, the relationships between environmental variables and adult lactose digestion capacity are highly confounded by the shared ancestry of many populations whose lactose digestion capacity has been tested. The three hypotheses for the evolution of high adult lactose digestion capacity are tested here using a comparative method of analysis that takes the problem of phylogenetic confounding into account. This analysis supports the hypothesis that high adult lactose digestion capacity is an adaptation to dairying but does not support the hypotheses that lactose digestion capacity is additionally selected for either at high latitudes or in highly arid environments. Furthermore, methods using maximum likelihood are used to show that the evolution of milking preceded the evolution of high lactose digestion.

Adult↗
PubMed2002

Reproductive biology of a Characidiinae (Osteichthyes, Characidae) from the Ubatiba River, Maricá-RJ.

The Ubatiba river is a coastal stream subject to stochastic spates all over the year and, Characidium sp.n. is among the twenty-two species that compose its ichthyofauna. In this study we analyse some traits of its reproductive biology and discuss whether the adopted strategy has causal relationship with the environmental variables. Specimens were collected in the upper Ubatiba river. Samplings, were carried out monthly by electrofishing, between Oct./94 and Sep./95. Some differences between male and female strategies were observed. Females were significantly (p < 0.05) bigger than males; length--weight relationship was different (p < 0.05) between sexes with the onset of sexual maturity occuring at smaller sizes among males. Reproductive investment is high for both males and females but higher for males, maximum Gonadosomatic Index for females and males were 40.97% and 44.90%, respectively. Reproductive specimens were registered all over the year, suggesting continuous reproduction. High values of fecundity were also registered varying from 1342 to 5535 eggs for ripe females of 4.4 and 7.0 cm, respectively and an amount of 1105 oocytes per grams of fish. We suggest that differences in the reproductive strategy, between sexes, determine the observed patterns in the size structure; the absence of males in the higher SL classes could be a consequence of high mortality rates and/or reduction in the growth rates as a precocity consequence in the onset of reproduction and/or high reproductive investment. Relationship between continuous reproduction and environmental condition could be explained as an adaptation to maximise supervivency of the young fishes that is: guarantee the species maintenance in a stochastic environment.

Adaptation, Biological↗
PubMed2006

Benthic impacts of intertidal oyster culture, with consideration of taxonomic sufficiency.

An investigation of the impacts from elevated intertidal Pacific oyster culture in a New Zealand estuary showed enhanced sedimentation beneath culture racks compared with other sites. Seabed elevation beneath racks was generally lower than between them, suggesting that topographic patterns more likely result from a local effect of rack structures on hydrodynamic processes than from enhanced deposition. Compared with control sites, seabed sediments within the farm had a greater silt/clay and organic content, and a lower redox potential and shear strength. While a marked trend in macrofaunal species richness was not evident, species composition and dominance patterns were consistent with a disturbance gradient, with farm effects not evident 35 m from the perimeter of the racks. Of the environmental variables measured, sediment shear strength was most closely associated with the distribution and density of macrofauna, suggesting that human-induced disturbance from farming operations may have contributed to the biological patterns. To evaluate the taxonomic sufficiency needed to document impacts, aggregation to the family level based on Linnean classification was compared with an aggregation scheme based on ;general groups' identifiable with limited taxonomic expertise. Compared with species-level analyses, spatial patterns of impact were equally discernible at both aggregation levels used, provided density rather than presence/absence data were used. Once baseline conditions are established and the efficacy of taxonomic aggregation demonstrated, a ;general group' scheme provides an appropriate and increasingly relevant tool for routine monitoring.

Animals↗
PubMed2006

Derivation of ozone flux-yield relationships for lettuce: a key horticultural crop.

Ozone flux-response relationships were derived for lettuce, employing a multiplicative approach to model the manner in which stomatal conductance is influenced by key environmental variables, using a dataset collected during field experimentation in Crete and yield-response relationships derived from parallel open-top chamber experiments. Regional agronomic practices were adopted throughout. Computed versus measured data revealed that the derived model explained 51% (P<0.001) of the observed variation in stomatal conductance. Concentration-based indices were compared with flux-based indices. Analyses revealed a significant relationship between accumulated stomatal ozone flux and yield employing flux threshold cut-offs up to 4 nmol m(-2) s(-1). Regressions employing very low or zero flux thresholds resulted in the strongest yield-flux relationships (explaining approximately 80% (P<0.05) of the variation in the dataset).

Crops, Agricultural↗
PubMed2004

Modelling the distributions of Culicoides bluetongue virus vectors in Sicily in relation to satellite-derived climate variables.

Surveillance data from 268 sites in Sicily are used to develop climatic models for prediction of the distribution of the main European bluetongue virus (BTV) vector Culicoides imicola Kieffer (Diptera: Ceratopogonidae) and of potential novel vectors, Culicoides pulicaris Linnaeus, Culicoides obsoletus group Meigen and Culicoides newsteadi Austen. The models containing the 'best' climatic predictors of distribution for each species, were selected from combinations of 40 temporally Fourier-processed remotely sensed variables and altitude at a 1 km spatial resolution using discriminant analysis. Kappa values of around 0.6 for all species models indicated substantial levels of agreement between model predictions and observed data. Whilst the distributions of C. obsoletus group and C. newsteadi were predicted by temperature variables, those of C. pulicaris and C. imicola were determined mainly by normalized difference vegetation index (NDVI), a variable correlated with soil moisture and vegetation biomass and productivity. These models were used to predict species presence in unsampled pixels across Italy and for C. imicola across Europe and North Africa. The predicted continuous presence of C. pulicaris along the appenine mountains, from north to south Italy, suggests BTV transmission may be possible in a large proportion of this region and that seasonal transhumance (seasonal movement of livestock between upland and lowland pastures) even in C. imicola-free areas should not generally be considered safe. The predicted distribution of C. imicola distribution shows substantial agreement with observed surveillance data from Greece and Iberia (including the Balearics) and parts of mainland Italy (Lazio, Tuscany and areas of the Ionian coast) but is generally much more restricted than the observed distribution (in Sardinia, Corsica and Morocco). The low number of presence sites for C. imicola in Sicily meant that only a restricted range of potential C. imicola habitats were included in the training set and that predictions could only be made within this range. Future modelling exercises will use abundance data collected according to a standardized protocol across the Mediterranean and, for Sicily in particular, should include non-climatic environmental variables that may influence breeding site suitability such as soil type.

Altitude↗
PubMed2005

A study of the environmental determinants of malaria and schistosomiasis in the Philippines using Remote Sensing and Geographic Information Systems.

Malaria and schistosomiasis are two water-related parasitic diseases affecting millions of people worldwide particularly tropical and subtropical countries. In the Philippines, malaria is found in 72 out of 78 provinces while schistosomiasis is endemic in 24 provinces. The Anopheles mosquito and the Oncomelania snail involved in the transmission of these diseases depend on certain environmental determinants that support mosquito and snail populations. This study, done for the first time in the Philippines, successfully showed how Remote Sensing (RS) and Geographical Information Systems (GIS) can be effectively used in showing how these environmental factors affect the spatial distribution of these two diseases. The study sites, i.e. the municipalities of Asuncion and Kapalong, are known endemic sites for both malaria and schistosomiasis. Georeferenced data enabled visualization of prevalence data in relation to physical maps thus facilitating assessment of disease situation in the two municipalities. RS and GIS data proved that other factors aside from climate influence the epidemiology of the diseases in the two sites. Topography and slope as main physical factors influence the vegetation cover, land use and soil type prevailing in particular areas. In addition, water sources especially irrigation networks differed in various places in the study sites in turn affecting the magnitude and distribution of malaria and schistosomiasis. Significant correlations found between the diseases and the environmental variables formed the basis for development of models to predict the disease prevalence in the two municipalities. Proximity to snail breeding sites and irrigation networks and the highly agricultural nature of the barangays were identified as the most common factors that define the high prevalence areas for schistosomiasis confirming the fact that conditions that support the snail populations will in turn favor the presence of the disease. For malaria, the predictive models included temperature, humidity, soil type, predominance of reproduction brush, presence of cultivated areas, distance from deep wells and distance from conventional water source which are in turn influenced by the factor of elevation.

Agriculture↗