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At least 955 records · Page 53Linked to original sources
PubMed2006

Temporal and spatial variability in stable isotope compositions of a freshwater mussel: implications for biomonitoring and ecological studies.

Stable isotopes can be used to elucidate ecological relationships in community and trophic studies. Findings are calibrated against baselines, e.g. from a producer or primary consumer, assumed to act as a reference to the isotopic context created by spatio-temporal attributes such as geography, climate, nutrient, and energy sources. The ability of an organism to accurately represent a community base depends on how, and over what time-scale, it assimilates ambient materials. Freshwater mussels have served as references for trophic studies of freshwater communities and as indicators of change in nutrient pollution load or source. Their suitability as reference animals has not yet been fully explored, however. We conducted a series of studies examining the suitability of freshwater mussels as isotopic baselines, using their ability to reflect variation in ambient nutrient loads as a case scenario. (1) We analyzed bivalve foot tissue delta(15)N and delta(13)C from 22 stream reaches in the Piedmont region of North Carolina, USA to show that compositions varied substantially among locations. Site mean bivalve delta(13)C values correlated with site ambient particulate organic matter (POM) delta(13)C values, and site mean bivalve delta(15)N values correlated with site ambient water dissolved delta(15)N-NO(3) values. (2) Similarity of results among sample types demonstrated that the minimally invasive hemolymph sample is a suitable substitute for foot tissue in delta(15)N analyses, and that small sample sizes generate means representative of a larger population. Both findings can help minimize the impact of sampling on imperiled freshwater mussel populations. (3) In a bivalve transplantation study we showed that hemolymph delta(15)N compositions responded to a shift in ambient dissolved delta(15)N-NO(3), although slowly. The tissue turnover time for bivalve hemolymph was 113 days. We conclude that bivalves serve best as biomonitors of chronic, rather than acute, fluctuations in stream nutrient loads, and provide initial evidence of their suitability as time-integrated isotopic baselines for community studies.

Animals↗
PubMed2005

Microsatellite data support subpopulation structuring among Basques.

Genomic diversity based on 13 short tandem repeat (STR) loci (D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, D16S539, TH01, TPOX, and CSF1PO) is reported for the first time in Basques from the provinces of Guipúzcoa and Navarre (Spain). STR data from previous studies on Basques from Alava and Vizcaya provinces were also examined using hierarchal analysis of molecular variance (AMOVA) and genetic admixture estimations to ascertain whether the Basques are genetically heterogeneous. To assess the genetic position of Basques in a broader geographic context, we conducted phylogenetic analyses based on F(ST) genetic distances [neighbor-joining trees and multidimensional scaling (MDS)] using data compiled in previous publications. The genetic profile of the Basque groups revealed distinctive regional partitioning of short tandem repeat (STR) diversity. Consistent with the above, native Basques clearly segregated from other populations from Europe (including Spain), North Africa, and the Middle East. The main line of genetic discontinuity inferred from the spatial variability of the microsatellite diversity in Basques significantly overlapped the geographic distribution of the Basque language. The genetic heterogeneity among native Basque groups correlates with the peculiar geography of peopling and marital structure in rural Basque zones and with language boundaries resulting from the uneven impact of Romance languages in the different Basque territories.

DNA↗
PubMed1994

Element reference values in tissues from inhabitants of the European Community. VI. Review of elements in blood, plasma and urine and a critical evaluation of reference values for the United Kingdom population.

Reference values for the concentration of elements in whole blood for the UK population are presented together with estimates for concentrations in plasma and urine. The blood data, when compared with other values obtained for Belgium, Denmark and Italy, obtained through the EURO-Terviht programme of the European Union, together with data from other countries, indicate similar concentrations. The data provide a basis for identifying the expected levels for the non-occupational exposed population against which differences attributable to various states of well-being, morbidity and mortality can be evaluated. However, it is also apparent that significant differences do exist which are related to geography and diet. In order to consider these differences, further improvements in the determination of elements in human tissues and fluids are required. Particular attention should be paid to that proportion of an element in the environment which is bioavailable together with its toxicity.

Autopsy↗
PubMed1993

Do places matter? A multi-level analysis of regional variations in health-related behaviour in Britain.

A number of commentators have argued that there is a distinctive geography of health-related behaviour. Behaviour has to be understood not only in terms of individual characteristics, but also in relation to local cultures. Places matter, and the context in which behaviour takes place is crucial for understanding and policy. Previous empirical research has been unable to operationalize these ideas and take simultaneous account of both individual compositional and aggregate contextual factors. The present paper addresses this shortcoming through a multi-level analysis of smoking and drinking behaviours recorded in a large-scale national survey. It suggests that place, expressed as regional differences, may be less important than previously implied.

Adolescent↗
PubMed1994

Coronary heart disease: trends in spatial inequalities and implications for health care planning in England.

The idea of health gain has recently received particular emphasis in health policy in England. One of the areas where there is considerable scope for health gain is in the reduction of mortality due to Coronary Heart Disease. Some reduction in mortality rates due to this cause have already been achieved in England in the 1980s. However, the change in standardised mortality rates varies around the country. A review of studies of geographies of declining CHD mortality shows that such geographical variation is typical of other countries which have recently experienced a reduction in the CHD epidemic. The paper presents the results of an analysis of change in spatial inequality in coronary heart disease mortality among the population aged 35-74 for the 190 District Health Authorities in England over the period 1982-1989. Data were derived from counts of cause-specific deaths and population estimates published by the Office of Population Censuses and Surveys. Various approaches were used to assess the change in spatial disparity which has accompanied the average overall reduction in mortality rates over the study period. The results show that the trends vary between age and sex groups in the population and that, particularly for older people, overall health gain across the country is being achieved at the cost of greater inequality in health between areas. The implications for local health strategies with respect to coronary heart disease reduction are discussed.

Adult↗
PubMed2004

Environmental exposure to PCBs and cancer incidence in eastern Slovakia.

In a population-based cross-sectional study, we compared serum levels of 15 polychlorinated biphenyl (PCB) congeners and three organochlorine pesticides in residents of two districts in eastern Slovakia, one with extensive environmental contamination from a former PCB production site (Michalovce) and the other matched on geography but with low (background) levels (Svidnik). The age-adjusted geometric means for sum of 15 measured PCB congeners were statistically significantly higher in subjects from the Michalovce district for both sexes: 3327.6 versus 1331.4 ng/g of lipid in males, 2751.8 versus 992.2 ng/g of lipid in females. Levels of DDE and DDT were also significantly higher, although the absolute differences were less pronounced. There was no substantial difference in HCB levels between the districts. We also conducted an ecologic study to compare cancer incidence occurring in these same two districts from 1985 through 1994. We calculated standardized incidence ratios (SIRs) and 95% confidence intervals for each district using indirect standardization and rates from eastern Slovakia. Among males from Michalovce (exposed), but not Svidnik (unexposed), there was an excess of cancer of the tongue (SIR=1.46; 1.06-1.96), stomach (SIR=1.15; 1.00-1.32), lung (SIR=1.14; 1.04-1.24), testis (SIR=1.40; 0.97-1.97), and kidney (SIR=1.23; 0.98-1.52), and lower than expected incidence of prostate cancer (SIR=0.83; 0.69-0.97); in contrast, there was an excess of peritoneal (SIR=3.05; 1.11-6.63) and laryngeal cancer (SIR=1.43; 0.99-1.98) in Svidnik not observed Michalovce. Among females from Michalovce, but not Svidnik, there was an excess of cancer of the lip (SIR=2.54; 1.53-3.96), stomach (SIR=1.22; 1.02-1.44), and lung (SIR=1.17; 0.94-1.45); in contrast, there was an excess of kidney (SIR=1.61; 1.03-2.40) and thyroid (SIR=1.97; 1.12-3.20) cancer in Svidnik not observed in Michalovce. Taken together, these results raise the possibility that high environmental exposure to organochlorines in the Michalovce district may be associated with higher rates of certain cancers, particularly stomach and lung cancer.

Age Factors↗
PubMed2005

Utility of stable isotopes ((13)C and (15)N) to demonstrate comparability between natural and experimental streams for environmental risk assessment.

Environmental safety of contaminants sometimes requires testing at the ecosystem level. Model ecosystems can serve as a surrogate to receiving waters for the assessor. Tools to verify that model ecosystems are good surrogates for natural receiving water systems have been based on structural attributes such as taxa lists. While examining taxa lists can be useful within a geography, they are less informative when comparing across different topographical and climatic regions. This paper illustrates an alternative approach that uses natural abundance ratios of nitrogen and carbon. Comparisons were made between the Procter and Gamble Co. (P and G) Experimental Stream Facility (ESF) and the East Fork Little Miami River (EFLMR). We also conducted stable isotopes releases of nitrogen ((15)NH(4)Cl) in the ESF and EFLMR. Results from the nitrogen releases for the ESF and EFLMR were compared to each other and to stable isotope releases conducted in 9 streams as part of the Lotic Intersite Nitrogen eXperiment (LINX). Preliminary evaluations of nitrogen uptake show that the uptake rate of ammonium for the P and G experimental streams (0.019 m(-1)) is similar to uptake rates in natural streams of similar flow and fits the regression of uptake length and discharge for the LINX streams. Nutrient flow data obtained in this study in most cases verified model (SISTM) predictions.

Carbon↗
PubMed2005

Geographical height variation among Ohio Caucasian male convicts born 1780-1849.

To more completely answer questions regarding health in the past, social scientists are utilizing previously underutilized data sources. This study focuses on one such source: penitentiary records, in order to examine geographical variation in height from a sample of 2554 male Caucasian convicts aged 23-45 years. Data collected include height, age, ancestry, nationality, and year and place of birth. Birth places were divided into five geographical areas corresponding roughly to the United States census geography divisions. Average stature for this sample was 68.4+/-2.5 in. (173.7+/-6.4 cm). Regression analyses on height, birth cohort, ancestry, nationality, and place of birth indicate significant but small differences in height across geographical areas. No significant differences were found due to birth cohort.

Adult↗
PubMed2005

Healing in places of decline: (re)imagining everyday landscapes in Hamilton, Ontario.

Ongoing interest in therapeutic landscapes has contributed noticeably to the development of a "post-medical geography of health" (Kearns, R.A., Professional Geographer 45 (1993) 139). Drawing on a variety of sources, including in-depth interviews and newspaper coverage from Hamilton, Canada, this paper explores the processes by which ordinary places are characterised as healthy or unhealthy, and investigates how health-affirming and health-denying places exist together in everyday life. We argue that it is possible for places to simultaneously hurt and heal, and that the therapeutic effect of place is largely contingent on individuals' physical and social locations. Further, we attempt to illustrate how these meanings are negotiated at a variety of different geographic scales.

Ecosystem↗
PubMed2005

Relocation of the 1936 Mojokerto skull discovery site near Perning, East Java.

The fossil calvaria known as the Mojokerto child's skull was discovered in 1936, but uncertainties have persisted about its paleoenvironmental context and geological age because of difficulties in relocating the discovery site. Past relocation efforts were hindered by inaccuracies in old base maps, intensive post-1930s agricultural terracing, and new tree and brush growth. Fortunately geologic cross sections and site photographs from 1936-1938-not fully utilized in past relocation fieldwork-closely circumscribe site geography and geology. These documents match the conditions at just one sandstone outcrop. It is situated on the southern margin of a topographic nose at the upper end of a approximately 18 m-wide gully ( approximately 0663760 m E, 9183430 m N, UTM Zone 49 M), approximately 15 m southeast of the Kumai et al. (1985) relocation. The relocated discovery bed is approximately 3.3 m of fossiliferous pebbly sandstone, a river-channel deposit cut into tuffaceous mudstone. The sandstone and mudstone beds correspond to original site descriptions. Pebbly sandstone is also found within the skull. The calvaria is well-preserved and taphonomically similar to large and fragile specimens found among several hundred vertebrate fossils excavated from the sandstone in 2001-2002. Since no well-preserved fossils were found intact at the surface of the sandstone, the good condition of the Mojokerto skull suggests that it was buried fully when discovered. The relocated hominin bed is the uppermost fluvial sandstone of a marine-deltaic sequence in the upper Pucangan Formation. The Mojokerto child probably died along the ancient seacoast, judging from the large extent of the deltaic facies and evidence that the calvaria experienced minimal transport. The relocated discovery bed is approximately 20 m stratigraphically above the horizon from which the widely cited 1.81+/-0.04 Ma (40)Ar/(39)Ar date for the skull was obtained. Additional field and laboratory results will be required to determine the skull's age.

Animals↗
PubMed2005

Surnames and dialects in France: population structure and cultural evolution.

To study the isonymy structure of France as related to local language variations, the surname distributions of 6.03 million telephone users registered for the year 2002 were analysed in the 21 conterminous regions, their 94 departments and in 809 towns of the Country. For regions and departments the differences among local dialects were quantified according to the dialecto-metrization of the Atlas Linguistique Français. We found that Lasker's distance between regions was correlated with geographic distance with r=0.692+/-0.040, while Euclidean (r=0.546+/-0.058) and Nei's (r=0.610+/-0.048) distances were less correlated. Slightly lower correlations were observed for departments. Also, dialectometric distance was correlated with geography (r=0.582+/-0.069 for regions and r=0.617+/-0.015 for departments). The correlations between Lasker and dialectometric matrix distances for regions and departments are r=0.625+/-0.046 and 0.544+/-0.014, respectively, indicating that the common cause generating surname and language diversity accounts for about 35% of the differentiation. Both Lasker and dialectometric distances identify very similar boundaries between Poitou, Centre, Bourgogne and Franche Comptée at the North, and Aquitaine, Limousin, Auvergne, Rhône-Alpes in the South. Average Fisher's alpha for France was 7877 the highest value observed for the European countries studied to date. The size of alpha in most French towns indicates considerable recent immigration.

Cultural Evolution↗
PubMed2005

Analysis of renal service provision in south and mid Wales.

OBJECTIVES: This paper estimates point prevalence of renal replacement therapy (RRT) utilization within population strata defined by geography and deprivation in south and mid Wales. It investigates spatial accessibility of main and satellite renal units by comparing population and patient numbers within bands of travel time. STUDY DESIGN: Prevalence study based on patient registers. METHODS: From a list of patient and renal unit locations, geocoded at the level of unit postcodes, and electoral division-level denominator population data, we calculated RRT point prevalence for the 16 unitary authorities in the study area, fifths of small area deprivation, and three bands of travel time from the nearest main renal unit and any (main or satellite) unit. RESULTS: Overall point prevalence was 633 per million population (pmp) and this varied from 256 to 780 pmp across unitary authorities. RRT prevalence was lower in more deprived areas. Sixty-nine percent of the population and 73% of patients lived within 30 min of a main renal unit. Eighty-four percent of the population and 88% of patients lived within 30 min of a main or satellite renal unit. CONCLUSIONS: The provision of satellite renal units has significantly improved spatial accessibility of RRT services. However, a substantial proportion of the population remains geographically distant from renal units. This has important implications for planning of future provision of RRT, given the inverse relationship between RRT acceptance and travel time, and the impact on quality of life of patients who travel frequently to renal units.

Geography↗
PubMed2005

The impact of a police drug crackdown on drug injectors' ability to practice harm reduction: a qualitative study.

This paper employs qualitative methods to explore the ramifications of a police drug crackdown on drug injectors' ability to practice harm reduction. Between August and December 2000, we conducted open-ended interviews with 40 illicit-drug-injecting residents of a New York City police precinct undergoing a crackdown. Interview topics included participants' experiences with police in the precinct and their drug use practices. Grounded theory methods were used to analyze resulting transcripts. Because place emerged as a salient analytic category, we also drew on elements of social geography to interpret results. The analysis suggests that particular crackdown tactics, notably frequent police searches of participants' bodies and elevated surveillance of the precinct's public spaces, reconfigured participants' experiences of their bodies and the public spaces comprising the precinct in ways that adversely affected their capacity to engage in harm reduction. Frequent police searches, for example, discouraged participants from carrying the injection equipment they needed to ensure that they could inject with a sterile syringe. Constant monitoring of local public spaces made it difficult for homeless women and men to inject safely. Simultaneously, participants expressed support for police actions that reduced public drug activity. Given these findings, we recommend the implementation of strategies, designed by partnerships of community groups and governmental and non-governmental organizations, which reduce public drug activity without imperiling injectors' health. Possible strategies include improving access to treatment and establishing safe injection spaces.

Adolescent↗
PubMed2006

Birth outcomes among urban African-American women: a multilevel analysis of the role of racial residential segregation.

Residential segregation is a common aspect of the urban experiences of African-Americans in the United States (US), yet few studies have considered how segregation might influence perinatal health. Here, we develop a conceptual model of relationships between segregation and birth outcomes and test the implications of the model in a sample of 434,376 singleton births to African-American women living in 225 US Metropolitan Statistical Areas (MSAs). Data from the National Center for Health Statistics 2002 birth files were linked to data from the 2000 US Census and two distinct measures of segregation: an index of isolation (the probability that an African-American resident will encounter another African-American resident in any random neighborhood encounter) and an index of clustering (the extent to which African-Americans live in contiguous neighborhoods). Using multilevel regression models, controlling for individual- and MSA-level socioeconomic status and other covariates, we found higher isolation was associated with lower birthweight, higher rates of prematurity and higher rates of fetal growth restriction. In contrast, higher clustering was associated with more optimal outcomes. We propose that isolation reflects factors associated with segregation that are deleterious to health including poor neighborhood quality, persistent discrimination and the intra-group diffusion of harmful health behaviors. Associations with clustering may reflect factors associated with segregation that are health-promoting such as African-American political power empowerment, social support and cohesion. Declines in isolation could represent positive steps toward improving birth outcomes among African-American infants while aspects of racial contiguity appear to be mitigating or indeed beneficial. Segregation is a complex multidimensional construct with both deleterious and protective influences on birth outcomes, depending on the dimensions under consideration. Further research to understand racial/ethnic and economic health disparities could benefit from a focus on the contributory role of neighborhood attributes associated with the dimensions segregation and other social geographies.

Adolescent↗
PubMed2006

Racial disparities in low birthweight and the contribution of residential segregation: a multilevel analysis.

This study investigates the geography of racial disparities in low birthweight in New York City by focusing on racial residential segregation and its effect on the risk of low birthweight among African-American infants and mothers. This cross-sectional multilevel analysis uses birth records at the individual level (n=96,882) and racial isolation indices at the census tract or neighborhood level (n=2095) to measure their independent and cross-level effects on low birthweight. This study found that residential segregation and neighborhood poverty operate at different scales to increase the risk of low birthweight. At the neighborhood scale residential segregation is positively and significantly associated with low birthweight, after controlling for individual-level risk factors and neighborhood poverty. Residential segregation explains neighborhood variation in low birthweight means and race effects across census tracts, which cannot be accounted for by neighborhood poverty alone. At the individual scale-increasing levels of residential segregation does not significantly reduce or exacerbate individual-level risk factors for low birthweight; whereas increasing levels of neighborhood poverty significantly eliminates the race effect and reduces the protective effect of being foreign-born on low birthweight, after controlling for other individual-level risk factors and residential segregation. These findings are contradictory to previous health research that shows protective mechanisms associated with ethnic density in local areas. It is likely that structural factors underlying residential segregation, i.e., racial isolation, impose additional stressors on African-American women that may offset or disguise positive attributes associated with ethnic density. However, as poverty is concentrated within these neighborhoods, differences between races in low birthweight cease to exist. This study demonstrates that residential segregation and neighborhood poverty are important determinants of racial disparity in low birthweight in New York City.

Black or African American↗
PubMed2004

Temporal diversification of Mesoamerican cichlid fishes across a major biogeographic boundary.

The Mexican Neovolcanic Plateau sharply divides the vertebrate fauna of Mesoamerica where the climate of both the neotropics and temperate North America gradually blend. Only a few vertebrate groups such as the Heroine cichlids, distributed from South America to the Rio Grande in North America, are found both north and south of the Neovolcanic Plateau. To better understand the geography and temporal diversification of cichlids at this geologic boundary, we used mitochondrial DNA sequences of the cytochrome b (cyt b) gene to reconstruct the relationships of 52 of the approximately 80 species of Heroine cichlids in Mesoamerica. Our analysis suggests several cichlids in South America should be considered as part of the Mesoamerican Heroine clade because they and the cichlids north of the Isthmus of Panama are clearly supported as monophyletic with respect to all other Neotropical cichlids. We also recovered a group containing species in Paratheraps+Paraneetroplus+Vieja as the sister clade to Herichthys. Herichthys is the only cichlid clade north of the Mexican Plateau and it is monophyletic. Non-parametric rate smoothing of cichlid cyt b sequence resulted in an estimated divergence time of approximately 6 million years for Herichthys. This temporal diversification is concordant with divergence times estimated for anurans in the genus Bufo, a group that exhibits a similar geographic distribution. Our results indicate the 5-million-year-old extension of the Mexican Neovolcanic Plateau to the Gulf Coast of Mexico has strongly influenced the current transition between the vertebrate faunas of the Neotropics and Nearctic.

Animals↗
PubMed2005

A phylogeny of cycads (Cycadales) inferred from chloroplast matK gene, trnK intron, and nuclear rDNA ITS region.

Phylogenetic relationships among the three families and 12 living genera of cycads were reconstructed by distance and parsimony criteria using three markers: the chloroplast matK gene, the chloroplast trnK intron and the nuclear ITS/5.8S rDNA sequence. All datasets indicate that Cycadaceae (including only the genus Cycas) is remotely related to other cycads, in which Dioon was resolved as the basal-most clade, followed by Bowenia and a clade containing the remaining nine genera. Encephalartos and Lepidozamia are closer to each other than to Macrozamia. The African genus Stangeria is embedded within the New World subfamily Zamiodeae. Therefore, Bowenia is an unlikely sister to Stangeria, contrary to the view that they form the Stangeriaceae. The generic status of Dyerocycas and Chigua is unsupportable as they are paraphyletic with Cycas and the Zamia, respectively. Nonsense mutations in the matK gene and indels in the other two datasets lend evidence to reinforce the above conclusions. According to the phylogenies, the past geography of the genera of cycads and the evolution of character states are hypothesized and discussed. Within the suborder Zamiieae, Stangeria, and the tribe Zamieae evolved significantly faster than other genera. The matK gene and ITS/5.8S region contain more useful information than the trnK intron in addressing phylogeny. Redelimitations of Zamiaceae, Stangeriaceae, subfamily Encephalartoideae and subtribe Macrozamiineae are necessary.

Chloroplasts↗
PubMed2005

Mitochondrial phylogeny of pine cone beetles (Scolytinae, Conophthorus) and their affiliation with geographic area and host.

Pine cone beetles (Conophthorus spp.) feed and kill immature cones of Pinus species, thereby reducing seed production and seriously impairing reforestation of forest ecosystems. Population variation of Conophthorus reproductive behavior has hampered the development of semiochemical control of these pests. This difficulty is compounded by a lack of taxonomic knowledge and species diagnostic characters. Researchers and managers rely, in part, on host associations and geographic locality for species identifications and these have arguable taxonomic utility. However, host use and/or geographic separation may influence Conophthorus lineage diversification. To improve Conophthorus taxonomy and understand the association of host and geography with lineage diversification, a phylogeny of 43 individuals, including all valid species and a robust sample of C. ponderosae from different hosts, is reconstructed using 785 nucleotides of the 3'-end of the mitochondrial cytochrome oxidase I gene. Thirty trees were recovered in a parsimony analysis and the strict consensus was well resolved and supported by branch support measures. Conophthorus was monophyletic but mitochondrial polyphyly was uncovered for several species. The data also suggested an underestimation of species diversity. Phylogenetically related Conophthorus lineages were significantly associated with geographic proximity but not with host, as indicated by comparisons of character optimized geographic distributions and host associations against randomized distributions of these attributes on the parsimony tree. These results suggest that geographic separation better explains the mode of Conophthorus lineage diversification than does host specialization. Based on these results, researchers and managers of Conophthorus should consider populations as potentially different evolutionary entities until species boundaries are delineated via a robust phylogenetic revision of Conophthorus.

Amino Acids↗