[What do functionally defined populations contribute to the explanation of regional differences in medical care?].

PubMed

Graf von Stillfried, D; Czihal, T

2014-02-01

Geographic variation in health care is increasingly subject to analysis and health policy aiming at the suitable allocation of resources and the reduction of unwarranted variation for the patient populations concerned. As in the case of area-level indicators, in most cases populations are geographically defined. The concept of geographically defined populations, however, may be self-limiting with respect to identifying the potential for improvement. As an alternative, we explored how a functional definition of populations would support defining the scope for reducing unwarranted geographical variations. Given that patients in Germany have virtually no limits in accessing physicians of their choice, we adapted a method that has been developed in the United States to create virtual networks of physicians based on commonly treated patients. Using the physician claims data under statutory insurance, which covers 90% of the population, we defined 43,006 populations-and networks-in 2010. We found that there is considerable variation between the population in terms of their risk structure and the share of the primary care practice in the total services provided. Moreover, there are marked differences in the size and structure of networks between cities, densely populated regions, and rural regions. We analyzed the variation for two area-level indicators: the proportion of diabetics with at least one HbA1c test per year for diabetics, and the proportion of patients with low back pain undergoing computed tomography and/or magnetic resonance imaging. Variation at the level of functionally defined populations proved to be larger than for geographically defined populations. The pattern of distribution gives evidence on the degree to which consensus targets could be reached and which networks need to be addressed in order to reduce unwarranted regional variation. The concept of functionally defined populations needs to be further developed before implementation.

Geographic variation in diapause induction: The grape berry moth (Lepidoptera: Tortricidae)

Treesearch

Jody Timer; Patrick C. Tobin; Michael C. Saunders

2010-01-01

Diapause in insects occurs in response to environmental cues, such as changes in photoperiod, and it is a major adaptation by which insects synchronize their activity with biotic resources and environmental constraints. For multivoltine agricultural insect pests, diapause initiation is an important consideration in management decisions, particularly toward the end of...

Functional acclimation across microgeographic scales in Dodonaea viscosa

PubMed Central

Baruch, Zdravko; Jones, Alice R; Hill, Kathryn E; McInerney, Francesca A; Blyth, Colette; Caddy-Retalic, Stefan; Christmas, Matthew J; Gellie, Nicholas J C; Lowe, Andrew J; Martin-Fores, Irene; Nielson, Kristine E

2018-01-01

Abstract Intraspecific plant functional trait variation provides mechanistic insight into persistence and can infer population adaptive capacity. However, most studies explore intraspecific trait variation in systems where geographic and environmental distances co-vary. Such a design reduces the certainty of trait–environment associations, and it is imperative for studies that make trait–environment associations be conducted in systems where environmental distance varies independently of geographic distance. Here we explored trait variation in such a system, and aimed to: (i) quantify trait variation of parent and offspring generations, and associate this variation to parental environments; (ii) determine the traits which best explain population differences; (iii) compare parent and offspring trait–trait relationships. We characterized 15 plant functional traits in eight populations of a shrub with a maximum separation ca. 100 km. Populations differed markedly in aridity and elevation, and environmental distance varied independently of geographic distance. We measured traits in parent populations collected in the field, as well as their offspring reared in greenhouse conditions. Parent traits regularly associated with their environment. These associations were largely lost in the offspring generation, indicating considerable phenotypic plasticity. An ordination of parent traits showed clear structure with strong influence of leaf area, specific leaf area, stomatal traits, isotope δ13C and δ15N ratios, and Narea, whereas the offspring ordination was less structured. Parent trait–trait correlations were in line with expectations from the leaf economic spectrum. We show considerable trait plasticity in the woody shrub over microgeographic scales (<100 km), indicating it has the adaptive potential within a generation to functionally acclimate to a range of abiotic conditions. Since our study shrub is commonly used for restoration in southern Australia and local populations do not show strong genetic differentiation in functional traits, the potential risks of transferring seed across the broad environmental conditions are not likely to be a significant issue.

Genetic diversity among brazilian isolates of beauveria bassiana: comparisons with non-brazilian isolates and other beauveria species

USGS Publications Warehouse

Fernandes, E.K.K.; Moraes, A.M.L.; Pacheco, R.S.; Rangel, D.E.N.; Miller, M.P.; Bittencourt, V.R.E.P.; Roberts, D.W.

2009-01-01

Aims: The genetic diversity of Beauveria bassiana was investigated by comparing isolates of this species to each other (49 from different geographical regions of Brazil and 4 from USA) and to other Beauveria spp. Methods and Results: The isolates were examined by multilocus enzyme electrophoresis (MLEE), amplified fragment length polymorphism (AFLP), and rDNA sequencing. MLEE and AFLP revealed considerable genetic variability among B. bassiana isolates. Several isolates from South and Southeast Brazil had high similarity coefficients, providing evidence of at least one population with clonal structure. There were clear genomic differences between most Brazilian and USA B. bassiana isolates. A Mantel test using data generated by AFLP provided evidence that greater geographical distances were associated with higher genetic distances. AFLP and rDNA sequencing demonstrated notable genotypic variation between B. bassiana and other Beauveria spp. Conclusion: Geographical distance between populations apparently is an important factor influencing genotypic variability among B. bassiana populations in Brazil. Significance and Impact of the Study: This study characterized many B. bassiana isolates. The results indicate that certain Brazilian isolates are considerably different from others and possibly should be regarded as separate species from B. bassiana sensu latu. The information on genetic variation among the Brazilian isolates, therefore, will be important to comprehending the population structure of B. bassiana in Brazil. ?? 2009 The Society for Applied Microbiology.

X-autosome incompatibilities in Drosophila melanogaster: tests of Haldane’s rule and geographic patterns within species

PubMed Central

Lachance, Joseph; True, John R.

2010-01-01

Substantial genetic variation exists in natural populations of Drosophila melanogaster. This segregating variation includes alleles at different loci that interact to cause lethality or sterility (synthetic incompatibilities). Fitness epistasis in natural populations has important implications for speciation and the rate of adaptive evolution. To assess the prevalence of epistatic fitness interactions, we placed naturally occurring X chromosomes into genetic backgrounds derived from different geographic locations. Considerable amounts of synthetic incompatibilities were observed between X chromosomes and autosomes: greater than 44% of all combinations were either lethal or sterile. Sex-specific lethality and sterility were also tested to determine whether Haldane's rule holds for within-species variation. Surprisingly, we observed an excess of female sterility in genotypes that were homozygous, but not heterozygous, for the X chromosome. The recessive nature of these incompatibilities is similar to that predicted for incompatibilities underlying Haldane’s rule. Our study also found higher levels of sterility and lethality for genomes that contain chromosomes from different geographical regions. These findings are consistent with the view that genomes are co-adapted gene complexes and that geography affects the likelihood of epistatic fitness interactions. PMID:20455929

Geographical Variation in the Terpene Composition of the Leaf Oil of Douglas Fir,

DTIC Science & Technology

The two forms of Douglas fir, Pseudotsuga menziesii var. menziesii and var. glauca, differ quite considerably with regard to the monoterpenes of...their leaf oils. Several chemical races, differing quantitatively in certain monoterpenes , appear to exist in each variety and the leaf oil composition seems to be particularly useful in classifying intermediate forms. (Author)

It's the Local Economy, Stupid! Geographic Wealth Dispersion and Conflict Outbreak Location

ERIC Educational Resources Information Center

Buhaug, Halvard; Gleditsch, Kristian Skrede; Holtermann, Helge; Ostby, Gudrun; Tollefsen, Andreas Foro

2011-01-01

Income varies considerably within countries and the locations where conflicts emerge are rarely typical or representative for states at large. Yet, most research on conflict has only examined national income averages and neglected spatial variation. The authors argue that civil conflicts are more likely to erupt in areas with low absolute income,…

Geographic variations in involuntary care and associations with the supply of health and social care: results from a nationwide study.

PubMed

Gandré, Coralie; Gervaix, Jeanne; Thillard, Julien; Macé, Jean-Marc; Roelandt, Jean-Luc; Chevreul, Karine

2018-04-06

Involuntary psychiatric care remains controversial. Geographic disparities in its use can challenge the appropriateness of the care provided when they do not result from different health needs of the population. These disparities should be reduced through dedicated health policies. However, their association with the supply of health and social care, which could be targeted by such policies, has been insufficiently studied. Our objectives were therefore to describe geographic variations in involuntary admission rates across France and to identify the characteristics of the supply of care which were associated with these variations. Involuntary admission rate per 100,000 adult inhabitants was calculated in French psychiatric sectors' catchment areas using 2012 data from the national psychiatric discharge database. Its variations were first described numerically and graphically. Several factors potentially associated with these variations were then considered in a negative binomial regression with an offset term accounting for the size of catchment areas. They included characteristics of the supply of care (public and private care, health and social care, hospital and community-based care, specialised and non-specialised care) as well as adjustment factors related to epidemiological characteristics of the population of each sector's catchment area and its level of urbanization. Such variables were extracted from complementary administrative databases. Supply characteristics associated with geographic variations were identified using a significance level of 0.05. Significant variations in involuntary admission rates were observed between psychiatric sectors' catchment areas with a coefficient of variation close to 80%. These variations were associated with some characteristics of the supply of health and social care in the sectors' catchment areas. Notably, an increase in the availability of community-based private psychiatrists and the capacity of housing institutions for disabled individuals was associated with a decrease in involuntary admission rates while an increase in the availability of general practitioners was associated with an increase in those rates. There is evidence of considerable variations in involuntary admission rates between psychiatric sectors' catchment areas. Our results provide lines of thoughts to reduce such variations, in particular by supporting an increase in the availability of upstream and downstream care in the community.

Ethnic and geographic variations in the epidemiology of childhood fractures in the United Kingdom.

PubMed

Moon, Rebecca J; Harvey, Nicholas C; Curtis, Elizabeth M; de Vries, Frank; van Staa, Tjeerd; Cooper, Cyrus

2016-04-01

Fractures are common in childhood, and there is considerable variation in the reported incidence across European countries, but few data relating to ethnic and geographic differences within a single country. We therefore aimed to determine the incidence of childhood fractures in the United Kingdom (UK), and to describe age-, ethnicity- and region- specific variations. The Clinical Practice Research Datalink (CPRD) contains anonymised electronic health records for approximately 7% of the UK population. The occurrence of a fracture between 1988 and 2012 was determined from the CPRD for all individuals <18years of age, and used to calculate fracture incidence rates for age, sex and ethnicity. Regional fracture incidence rates were also calculated based on general practitioner location within 14 Strategic Health Authorities (SHA) within the UK. The overall fracture incidence rate was 137 per 10,000 person-years (py). This was higher in boys (169 per 10,000 py) than girls (103 per 10,000 py) and white children (150 per 10,000 py) compared to those of black (64 per 10,000 py) and South Asian (81 per 10,000 py) ethnicity. Marked geographic variation in incidence was observed. The highest fracture rates were observed in Wales, where boys and girls had 1.82 and 1.97 times greater incidence, respectively, than those residing in Greater London. In the period 1988-2012, there was marked geographic and ethnic variation in childhood fracture incidence across the UK. These findings also implicate lifestyle and socio-economic differences associated with location and ethnicity, and are relevant to policy makers in the UK and internationally. Copyright © 2016 Elsevier Inc. All rights reserved.

Geographic distribution of haplotype diversity at the bovine casein locus

PubMed Central

Jann, Oliver C; Ibeagha-Awemu, Eveline M; Özbeyaz, Ceyhan; Zaragoza, Pilar; Williams, John L; Ajmone-Marsan, Paolo; Lenstra, Johannes A; Moazami-Goudarzi, Katy; Erhardt, Georg

2004-01-01

The genetic diversity of the casein locus in cattle was studied on the basis of haplotype analysis. Consideration of recently described genetic variants of the casein genes which to date have not been the subject of diversity studies, allowed the identification of new haplotypes. Genotyping of 30 cattle breeds from four continents revealed a geographically associated distribution of haplotypes, mainly defined by frequencies of alleles at CSN1S1 and CSN3. The genetic diversity within taurine breeds in Europe was found to decrease significantly from the south to the north and from the east to the west. Such geographic patterns of cattle genetic variation at the casein locus may be a result of the domestication process of modern cattle as well as geographically differentiated natural or artificial selection. The comparison of African Bos taurus and Bos indicus breeds allowed the identification of several Bos indicus specific haplotypes (CSN1S1*C-CSN2*A2-CSN3*AI/CSN3*H) that are not found in pure taurine breeds. The occurrence of such haplotypes in southern European breeds also suggests that an introgression of indicine genes into taurine breeds could have contributed to the distribution of the genetic variation observed. PMID:15040901

The Effect of Geographic Units of Analysis on Measuring Geographic Variation in Medical Services Utilization.

PubMed

Kim, Agnus M; Park, Jong Heon; Kang, Sungchan; Hwang, Kyosang; Lee, Taesik; Kim, Yoon

2016-07-01

We aimed to evaluate the effect of geographic units of analysis on measuring geographic variation in medical services utilization. For this purpose, we compared geographic variations in the rates of eight major procedures in administrative units (districts) and new areal units organized based on the actual health care use of the population in Korea. To compare geographic variation in geographic units of analysis, we calculated the age-sex standardized rates of eight major procedures (coronary artery bypass graft surgery, percutaneous transluminal coronary angioplasty, surgery after hip fracture, knee-replacement surgery, caesarean section, hysterectomy, computed tomography scan, and magnetic resonance imaging scan) from the National Health Insurance database in Korea for the 2013 period. Using the coefficient of variation, the extremal quotient, and the systematic component of variation, we measured geographic variation for these eight procedures in districts and new areal units. Compared with districts, new areal units showed a reduction in geographic variation. Extremal quotients and inter-decile ratios for the eight procedures were lower in new areal units. While the coefficient of variation was lower for most procedures in new areal units, the pattern of change of the systematic component of variation between districts and new areal units differed among procedures. Geographic variation in medical service utilization could vary according to the geographic unit of analysis. To determine how geographic characteristics such as population size and number of geographic units affect geographic variation, further studies are needed.

Regional isolation in the Balkan region: an analysis of craniofacial variation.

PubMed

Ross, Ann H

2004-05-01

Biological variation is investigated among contemporary Croatians, Bosnians, American whites, and other multitemporal Balkan populations (World War II Croatians, Macedonians, and Greeks) via multivariate statistics and distance measures of the craniofacial complex. This study demonstrates that there is considerable variation among groups of European ancestry. Bosnians and Croatians who are thought to be relatively homogenous and historically to originate from the same Slav ancestry show local variations. While environmental plasticity has been used to explain cranial changes among human groups, it does not adequately explain the variation observed between Bosnians and Croatians. It is an oversimplification to exclusively attribute the vast range of variability observed among local as well as geographic populations to environmental adaptations. Copyright 2003 Wiley-Liss, Inc.

A multiple indicator, multiple cause method for representing social capital with an application to psychological distress

NASA Astrophysics Data System (ADS)

Congdon, Peter

2010-03-01

This paper describes a structural equation methodology for obtaining social capital scores for survey subjects from multiple indicators of social support, neighbourhood and trust perceptions, and memberships of organizations. It adjusts for variation that is likely to occur in levels of social capital according to geographic context (e.g. level of area deprivation, geographic region, level of urbanity) and demographic group. Social capital is used as an explanatory factor for psychological distress using data from the 2006 Health Survey for England. A highly significant effect of social capital in reducing the chance of psychiatric caseness is obtained after controlling for other individual and geographic risk factors. Allowing for social capital has considerable effects on the impacts on psychiatric health of other risk factors. In particular, the impact of area deprivation category is much reduced. There is also evidence of significant differentiation in social capital between population categories and geographic contexts.

Comparison of storm-time changes of geomagnetic field at ground and at MAGSAT altitudes, part 3

NASA Technical Reports Server (NTRS)

Dejesusparada, N. (Principal Investigator); Kane, R. P.; Trivedi, N. B.

1982-01-01

The latitudinal distributions of delta H, delta X, delta Y, and delta Z were studied for quiet and disturbed periods. For quiet periods, the average patterns showed some variations common to dusk and dawn, thus indicating probable ground anomaly. However, there were significant differences too between dusk and dawn, indicating considerable diurnal variation effects. Particularly in delta Y, these effects were large and were symmetric about the dip equator. For disturbed day passes, the quiet day patterns were considered as base levels and the latter were subtracted from the former. The resulting residual latitudinal patterns were, on the average, symmetric about the geographical equator. However, individual passes showed considerable north-south asymmetries, probably indicating meanderings of the central plane of the magnetospheric ring current.

Geographic considerations for fire management in the Eastern United States: geomorphology and topography, soils, and climate

Treesearch

Barton D. Clinton; James M. Vose; Erika C. Cohen

2012-01-01

Across the Eastern United States, there is on average an estimated 36 MT ha–1 (16 tons ac–1) of dead woody fuel (Chojnacky and others 2004). Variations in fuel type, size, and flammability make the selection of treatment options critical for effective fuels management. The region is a complex landscape characterized by...

Commentary 1: The Challenging Task of Addressing Power, Control, and Influence in Sibling Relationships after the First Two Decades of Life

ERIC Educational Resources Information Center

Bedford, Victoria Hilkevitch

2017-01-01

Extending the topic of power, control, and influence in the sibling relationship past the years covered in this issue is not an easy task because most adult siblings neither interact frequently nor live in geographic proximity, although there are considerable ethnic and social class variations. Thus, there are limited opportunities to observe how…

National Trends and Geographic Variation in Availability of Home Health Care: 2002–2015

PubMed Central

Wang, Yun; Leifheit-Limson, Erica C; Fine, Jonathan; Pandolfi, Michelle M; Gao, Yan; Liu, Fanglin; Eckenrode, Sheila; Lichtman, Judith H

2017-01-01

Objectives To evaluate national trends and geographic variation in the availability of home health care from 2002–2015 and identify county-specific characteristics associated with home health care. Design Observational study Setting All counties in the United States Participants All Medicare-certified home health agencies included in the Centers for Medicare & Medicaid Services Home Health Compare system. Measurements County-specific availability of home health care, defined as the number of available home health agencies that provided services to a given county per 100,000 population aged ≥18 years. Results The study included 15,184 Medicare-certified home health agencies that served 97% of U.S. ZIP codes. Between 2002–2003 and 2014–2015, the county-specific number of available home health agencies per 100,000 population aged ≥18 years increased from 14.7 to 21.8 and the median (inter-quartile range) population that was serviced by at least one home health agency increased from 403,605 (890,329) to 455,488 (1,039,328). Considerable geographic variation in the availability of home health care was observed. The West, North-East, and South Atlantic regions had lower home health care availability than the Central regions, and this pattern persisted over the study period. Counties with higher median income, a larger senior population, higher rates of households without a car and low access to stores, more obesity, greater inactivity, and higher proportions of non-Hispanic white, non-Hispanic black, and Hispanic populations were more likely to have higher availability of home health care. Conclusion The availability of home health care increased nationwide during the study period, but there was much geographic variation. PMID:28322441

Geographic Variation of Diapause and Sensitive Stages of Photoperiodic Response in Laodelphax striatellus Fallén (Hemiptera: Delphacidae)

PubMed Central

Hou, Yang-Yang; Xu, Lan-Zhen; Wu, Yan; Wang, Peng; Shi, Jin-Jian; Zhai, Bao-Ping

2016-01-01

Large numbers of the small brown planthopper Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae) occur in temperate regions, causing severe losses in rice, wheat, and other economically important crops. The planthoppers enter diapause in the third- or fourth-instar nymph stage, induced by short photoperiods and low temperatures. To investigate the geographic variation in L. striatellus diapause, we compared the incidence of nymphal diapause under various constant temperature (20 and 27°C) and a photoperiod of 4:20, 8:16, 10:14, 12:12, 14:10, and 16:8 (L:D) h regimes among three populations collected from Hanoi (21.02° N, 105.85° E, northern Vietnam), Jiangyan (32.51° N, 120.15° E, eastern China), and Changchun (43.89° N, 125.32° E, north-eastern China). Our results indicated that there were significant geographic variations in the diapause of L. striatellus. When the original latitude of the populations increased, higher diapause incidence and longer critical photoperiod (CP) were exhibited. The CPs of the Jiangyan and Changchun populations were ∼12 hr 30 min and 13 hr at 20°C, and 11 hr and 11 hr 20 min at 27°C, respectively. The second- and third-instar nymphs were at the stage most sensitive to the photoperiod. However, when the fourth- and fifth-instar nymphs were transferred to a long photoperiod, the diapause-inducing effect of the short photoperiod on young instars was almost reversed. The considerable geographic variations in the nymphal diapause of L. striatellus reflect their adaptation in response to a variable environment and provide insights to develop effective pest management strategies. PMID:26839318

National Trends and Geographic Variation in Availability of Home Health Care: 2002-2015.

PubMed

Wang, Yun; Leifheit-Limson, Erica C; Fine, Jonathan; Pandolfi, Michelle M; Gao, Yan; Liu, Fanglin; Eckenrode, Sheila; Lichtman, Judith H

2017-07-01

To evaluate national trends and geographic variation in the availability of home health care from 2002 to 2015 and identify county-specific characteristics associated with home health care. Observational study. All counties in the United States. All Medicare-certified home health agencies included in the Centers for Medicare & Medicaid Services Home Health Compare system. County-specific availability of home health care, defined as the number of available home health agencies that provided services to a given county per 100,000 population aged ≥18 years. The study included 15,184 Medicare-certified home health agencies that served 97% of U.S. ZIP codes. Between 2002-2003 and 2014-2015, the county-specific number of available home health agencies per 100,000 population aged ≥18 years increased from 14.7 to 21.8 and the median (inter-quartile range) population that was serviced by at least one home health agency increased from 403,605 (890,329) to 455,488 (1,039,328). Considerable geographic variation in the availability of home health care was observed. The West, North East, and South Atlantic regions had lower home health care availability than the Central regions, and this pattern persisted over the study period. Counties with higher median income, a larger senior population, higher rates of households without a car and low access to stores, more obesity, greater inactivity, and higher proportions of non-Hispanic white, non-Hispanic black, and Hispanic populations were more likely to have higher availability of home health care. The availability of home health care increased nationwide during the study period, but there was much geographic variation. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

Geographic Variation of Diapause and Sensitive Stages of Photoperiodic Response in Laodelphax striatellus Fallén (Hemiptera: Delphacidae).

PubMed

Hou, Yang-Yang; Xu, Lan-Zhen; Wu, Yan; Wang, Peng; Shi, Jin-Jian; Zhai, Bao-Ping

2016-01-01

Large numbers of the small brown planthopper Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae) occur in temperate regions, causing severe losses in rice, wheat, and other economically important crops. The planthoppers enter diapause in the third- or fourth-instar nymph stage, induced by short photoperiods and low temperatures. To investigate the geographic variation in L. striatellus diapause, we compared the incidence of nymphal diapause under various constant temperature (20 and 27 °C) and a photoperiod of 4:20, 8:16, 10:14, 12:12, 14:10, and 16:8 (L:D) h regimes among three populations collected from Hanoi (21.02° N, 105.85° E, northern Vietnam), Jiangyan (32.51° N, 120.15° E, eastern China), and Changchun (43.89° N, 125.32° E, north-eastern China). Our results indicated that there were significant geographic variations in the diapause of L. striatellus. When the original latitude of the populations increased, higher diapause incidence and longer critical photoperiod (CP) were exhibited. The CPs of the Jiangyan and Changchun populations were ∼ 12 hr 30 min and 13 hr at 20 °C, and 11 hr and 11 hr 20 min at 27 °C, respectively. The second- and third-instar nymphs were at the stage most sensitive to the photoperiod. However, when the fourth- and fifth-instar nymphs were transferred to a long photoperiod, the diapause-inducing effect of the short photoperiod on young instars was almost reversed. The considerable geographic variations in the nymphal diapause of L. striatellus reflect their adaptation in response to a variable environment and provide insights to develop effective pest management strategies. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

Application of geographically-weighted regression analysis to assess risk factors for malaria hotspots in Keur Soce health and demographic surveillance site.

PubMed

Ndiath, Mansour M; Cisse, Badara; Ndiaye, Jean Louis; Gomis, Jules F; Bathiery, Ousmane; Dia, Anta Tal; Gaye, Oumar; Faye, Babacar

2015-11-18

In Senegal, considerable efforts have been made to reduce malaria morbidity and mortality during the last decade. This resulted in a marked decrease of malaria cases. With the decline of malaria cases, transmission has become sparse in most Senegalese health districts. This study investigated malaria hotspots in Keur Soce sites by using geographically-weighted regression. Because of the occurrence of hotspots, spatial modelling of malaria cases could have a considerable effect in disease surveillance. This study explored and analysed the spatial relationships between malaria occurrence and socio-economic and environmental factors in small communities in Keur Soce, Senegal, using 6 months passive surveillance. Geographically-weighted regression was used to explore the spatial variability of relationships between malaria incidence or persistence and the selected socio-economic, and human predictors. A model comparison of between ordinary least square and geographically-weighted regression was also explored. Vector dataset (spatial) of the study area by village levels and statistical data (non-spatial) on malaria confirmed cases, socio-economic status (bed net use), population data (size of the household) and environmental factors (temperature, rain fall) were used in this exploratory analysis. ArcMap 10.2 and Stata 11 were used to perform malaria hotspots analysis. From Jun to December, a total of 408 confirmed malaria cases were notified. The explanatory variables-household size, housing materials, sleeping rooms, sheep and distance to breeding site returned significant t values of -0.25, 2.3, 4.39, 1.25 and 2.36, respectively. The OLS global model revealed that it explained about 70 % (adjusted R(2) = 0.70) of the variation in malaria occurrence with AIC = 756.23. The geographically-weighted regression of malaria hotspots resulted in coefficient intercept ranging from 1.89 to 6.22 with a median of 3.5. Large positive values are distributed mainly in the southeast of the district where hotspots are more accurate while low values are mainly found in the centre and in the north. Geographically-weighted regression and OLS showed important risks factors of malaria hotspots in Keur Soce. The outputs of such models can be a useful tool to understand occurrence of malaria hotspots in Senegal. An understanding of geographical variation and determination of the core areas of the disease may provide an explanation regarding possible proximal and distal contributors to malaria elimination in Senegal.

How will provider-focused payment reform impact geographic variation in Medicare spending?

PubMed

Auerbach, David; Mehrotra, Ateev; Hussey, Peter; Huckfeldt, Peter J; Alpert, Abby; Lau, Christopher; Shier, Victoria

2015-06-01

The Institute of Medicine has recently argued against a value index as a mechanism to address geographic variation in spending and instead promoted payment reform targeted at individual providers. It is unknown whether such provider-focused payment reform reduces geographic variation in spending. We estimated the potential impact of 3 Medicare provider-focused payment policies-pay-for-performance, bundled payment, and accountable care organizations-on geographic variation in Medicare spending across Hospital Referral Regions (HRRs). We compared geographic variation in spending, measured using the coefficient of variation (CV) across HRRs, between the baseline case and a simulation of each of the 3 policies. Policy simulation based on 2008 national Medicare data combined with other publicly available data. Compared with the baseline (CV, 0.171), neither pay-for-performance nor accountable care organizations would change geographic variation in spending (CV, 0.171), while bundled payment would modestly reduce geographic variation (CV, 0.165). In our models, the bundled payment for inpatient and post acute care services in Medicare would modestly reduce geographic variation in spending, but neither accountable care organizations nor pay-for-performance appear to have an impact.

A multi-perspective view of genetic variation in Cameroon.

PubMed

Coia, V; Brisighelli, F; Donati, F; Pascali, V; Boschi, I; Luiselli, D; Battaggia, C; Batini, C; Taglioli, L; Cruciani, F; Paoli, G; Capelli, C; Spedini, G; Destro-Bisol, G

2009-11-01

In this study, we report the genetic variation of autosomal and Y-chromosomal microsatellites in a large Cameroon population dataset (a total of 11 populations) and jointly analyze novel and previous genetic data (mitochondrial DNA and protein coding loci) taking geographic and cultural factors into consideration. The complex pattern of genetic variation of Cameroon can in part be described by contrasting two geographic areas (corresponding to the northern and southern part of the country), which differ substantially in environmental, biological, and cultural aspects. Northern Cameroon populations show a greater within- and among-group diversity, a finding that reflects the complex migratory patterns and the linguistic heterogeneity of this area. A striking reduction of Y-chromosomal genetic diversity was observed in some populations of the northern part of the country (Podokwo and Uldeme), a result that seems to be related to their demographic history rather than to sampling issues. By exploring patterns of genetic, geographic, and linguistic variation, we detect a preferential correlation between genetics and geography for mtDNA. This finding could reflect a female matrimonial mobility that is less constrained by linguistic factors than in males. Finally, we apply the island model to mitochondrial and Y-chromosomal data and obtain a female-to-male migration Nnu ratio that was more than double in the northern part of the country. The combined effect of the propensity to inter-populational admixture of females, favored by cultural contacts, and of genetic drift acting on Y-chromosomal diversity could account for the peculiar genetic pattern observed in northern Cameroon.

Educational inequalities in self-rated health across US states and European countries.

PubMed

Präg, Patrick; Subramanian, S V

2017-07-01

The US shows a distinct health disadvantage when compared to other high-income nations. A potential lever to reduce this disadvantage is to improve the health situation of lower socioeconomic groups. Our objective is to explore how the considerable within-US variation in health inequalities compares to the health inequalities across other Western countries. Representative survey data from 44 European countries and the US federal states were obtained from the fourth wave of the European Values Study (EVS) and the 2008 wave of the Behavioral Risk Factor Surveillance System. Using binary logistic regression, we analyze different forms of educational inequalities in self-rated health (SRH), adjusted for age and sex. The extent of educational inequalities in SRH varies considerably over European countries and US states; with US states in general showing greater inequality, however, differences between US states and European countries are less clear than commonly assumed. The US has considerable differences in educational inequalities in SRH across geographic locations. To understand the reasons for the US health disadvantage, comparative research has to take into account the vast variation in health inequalities within the US.

Geographical Pattern and Environmental Correlates of Regional-Scale General Flowering in Peninsular Malaysia

PubMed Central

Numata, Shinya; Yasuda, Masatoshi; Suzuki, Ryo O.; Hosaka, Tetsuro; Noor, Nur Supardi Md.; Fletcher, Christine D.; Hashim, Mazlan

2013-01-01

In South-East Asian dipterocarp forests, many trees synchronize their reproduction at the community level, but irregularly, in a phenomenon known as general flowering (GF). Several proximate cues have been proposed as triggers for the synchronization of Southeast Asian GF, but the debate continues, as many studies have not considered geographical variation in climate and flora. We hypothesized that the spatial pattern of GF forests is explained by previously proposed climatic cues if there are common cues for GF among regions. During the study, GF episodes occurred every year, but the spatial occurrence varied considerably from just a few forests to the whole of Peninsular Malaysia. In 2001, 2002 and 2005, minor and major GF occurred widely throughout Peninsular Malaysia (GF2001, GF2002, and GF2005), and the geographical patterns of GF varied between the episodes. In the three regional-scale GF episodes, most major events occurred in regions where prolonged drought (PD) had been recorded prior, and significant associations between GF scores and PD were found in GF2001 and GF2002. However, the frequency of PD was higher than that of GF throughout the peninsula. In contrast, low temperature (LT) was observed during the study period only before GF2002 and GF2005, but there was no clear spatial relationship between GF and LT in the regional-scale episodes. There was also no evidence that last GF condition influenced the magnitude of GF. Thus, our results suggest that PD would be essential to trigger regional-scale GF in the peninsula, but also that PD does not fully explain the spatial and temporal patterns of GF. The coarse relationships between GF and the proposed climatic cues may be due to the geographical variation in proximate cues for GF, and the climatic and floristic geographical variations should be considered to understand the proximate factors of GF. PMID:24260159

Geographical pattern and environmental correlates of regional-scale general flowering in Peninsular Malaysia.

PubMed

Numata, Shinya; Yasuda, Masatoshi; Suzuki, Ryo O; Hosaka, Tetsuro; Noor, Nur Supardi Md; Fletcher, Christine D; Hashim, Mazlan

2013-01-01

In South-East Asian dipterocarp forests, many trees synchronize their reproduction at the community level, but irregularly, in a phenomenon known as general flowering (GF). Several proximate cues have been proposed as triggers for the synchronization of Southeast Asian GF, but the debate continues, as many studies have not considered geographical variation in climate and flora. We hypothesized that the spatial pattern of GF forests is explained by previously proposed climatic cues if there are common cues for GF among regions. During the study, GF episodes occurred every year, but the spatial occurrence varied considerably from just a few forests to the whole of Peninsular Malaysia. In 2001, 2002 and 2005, minor and major GF occurred widely throughout Peninsular Malaysia (GF2001, GF2002, and GF2005), and the geographical patterns of GF varied between the episodes. In the three regional-scale GF episodes, most major events occurred in regions where prolonged drought (PD) had been recorded prior, and significant associations between GF scores and PD were found in GF2001 and GF2002. However, the frequency of PD was higher than that of GF throughout the peninsula. In contrast, low temperature (LT) was observed during the study period only before GF2002 and GF2005, but there was no clear spatial relationship between GF and LT in the regional-scale episodes. There was also no evidence that last GF condition influenced the magnitude of GF. Thus, our results suggest that PD would be essential to trigger regional-scale GF in the peninsula, but also that PD does not fully explain the spatial and temporal patterns of GF. The coarse relationships between GF and the proposed climatic cues may be due to the geographical variation in proximate cues for GF, and the climatic and floristic geographical variations should be considered to understand the proximate factors of GF.

Amazonian phylogeography: mtDNA sequence variation in arboreal echimyid rodents (Caviomorpha).

PubMed

da Silva, M N; Patton, J L

1993-09-01

Patterns of evolutionary relationships among haplotype clades of sequences of the mitochondrial cytochrome b DNA gene are examined for five genera of arboreal rodents of the Caviomorph family Echimyidae from the Amazon Basin. Data are available for 798 bp of sequence from a total of 24 separate localities in Peru, Venezuela, Bolivia, and Brazil for Mesomys, Isothrix, Makalata, Dactylomys, and Echimys. Sequence divergence, corrected for multiple hits, is extensive, ranging from less than 1% for comparisons within populations of over 20% among geographic units within genera. Both the degree of differentiation and the geographic patterning of the variation suggest that more than one species composes the Amazonian distribution of the currently recognized Mesomys hispidus, Isothrix bistriata, Makalata didelphoides, and Dactylomys dactylinus. There is general concordance in the geographic range of haplotype clades for each of these taxa, and the overall level of differentiation within them is largely equivalent. These observations suggest that a common vicariant history underlies the respective diversification of each genus. However, estimated times of divergence based on the rate of third position transversion substitutions for the major clades within each genus typically range above 1 million years. Thus, allopatric isolation precipitating divergence must have been considerably earlier than the late Pleistocene forest fragmentation events commonly invoked for Amazonian biota.

Patterns and causes of geographic variation in bat echolocation pulses.

PubMed

Jiang, Tinglei; Wu, Hui; Feng, Jiang

2015-05-01

Evolutionary biologists have a long-standing interest in how acoustic signals in animals vary geographically, because divergent ecology and sensory perception play an important role in speciation. Geographic comparisons are valuable in determining the factors that influence divergence of acoustic signals. Bats are social mammals and they depend mainly on echolocation pulses to locate prey, to navigate and to communicate. Mounting evidence shows that geographic variation of bat echolocation pulses is common, with a mean 5-10 kHz differences in peak frequency, and a high level of individual variation may be nested in this geographical variation. However, understanding the geographic variation of echolocation pulses in bats is very difficult, because of differences in sample and statistical analysis techniques as well as the variety of factors shaping the vocal geographic evolution. Geographic differences in echolocation pulses of bats generally lack latitudinal, longitudinal and elevational patterns, and little is known about vocal dialects. Evidence is accumulating to support the fact that geographic variation in echolocation pulses of bats may be caused by genetic drift, cultural drift, ecological selection, sexual selection and social selection. Future studies could relate geographic differences in echolocation pulses to social adaptation, vocal learning strategies and patterns of dispersal. In addition, new statistical techniques and acoustic playback experiments may help to illustrate the causes and consequences of the geographic evolution of echolocation pulse in bats. © 2015 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

Changes in geographic variation in the use of percutaneous coronary intervention for stable ischemic heart disease after publication of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial.

PubMed

Mohan, Arun V; Fazel, Reza; Huang, Pei-Hsiu; Shen, Yu-Chu; Howard, David

2014-01-01

Clinical uncertainty is cited as a cause of geographic variation. However, little is known about the effect of comparative effectiveness research on variation. We examined whether geographic variation in the use of percutaneous coronary intervention (PCI) for stable ischemic heart disease (SIHD) declined after publication of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial. We examined changes in utilization and geographic variation in 67 hospital referral regions using the State Inpatient Databases. We compared age- and sex-adjusted rates of PCI for SIHD before (2006) and after (2008) publication of the COURAGE trial and compared those with contemporaneous changes in PCI volume for acute coronary syndrome. A total of 272,659 PCIs for SIHD from 526 hospitals were included in the analysis. After the publication of the COURAGE trial, PCI volume for SIHD declined by 25% (P<0.001) and decreased by 12% for acute coronary syndrome (P<0.001). This was predominantly attributable to changes in hospital referral regions with the highest levels of utilization pre-COURAGE trial (35% decline in the highest tertile versus 18% in the lowest). As measured by the systematic component of variation, there was substantial geographic variation in the use of PCI for SIHD preceding the publication of the COURAGE trial. Variation declined by 28% (0.53 versus 0.40) after publication, but geographic variation remained higher for SIHD than acute coronary syndrome (0.40 versus 0.17). There was a substantial decline in the use of and geographic variation in PCI for SIHD after the publication of the COURAGE trial. However, geographic variation in the use of PCI for SIHD remained high.

A population genomics approach shows widespread geographical distribution of cryptic genomic forms of the symbiotic fungus Rhizophagus irregularis.

PubMed

Savary, Romain; Masclaux, Frédéric G; Wyss, Tania; Droh, Germain; Cruz Corella, Joaquim; Machado, Ana Paula; Morton, Joseph B; Sanders, Ian R

2018-01-01

Arbuscular mycorrhizal fungi (AMF; phylum Gomeromycota) associate with plants forming one of the most successful microbe-plant associations. The fungi promote plant diversity and have a potentially important role in global agriculture. Plant growth depends on both inter- and intra-specific variation in AMF. It was recently reported that an unusually large number of AMF taxa have an intercontinental distribution, suggesting long-distance gene flow for many AMF species, facilitated by either long-distance natural dispersal mechanisms or human-assisted dispersal. However, the intercontinental distribution of AMF species has been questioned because the use of very low-resolution markers may be unsuitable to detect genetic differences among geographically separated AMF, as seen with some other fungi. This has been untestable because of the lack of population genomic data, with high resolution, for any AMF taxa. Here we use phylogenetics and population genomics to test for intra-specific variation in Rhizophagus irregularis, an AMF species for which genome sequence information already exists. We used ddRAD sequencing to obtain thousands of markers distributed across the genomes of 81 R. irregularis isolates and related species. Based on 6 888 variable positions, we observed significant genetic divergence into four main genetic groups within R. irregularis, highlighting that previous studies have not captured underlying genetic variation. Despite considerable genetic divergence, surprisingly, the variation could not be explained by geographical origin, thus also supporting the hypothesis for at least one AMF species of widely dispersed AMF genotypes at an intercontinental scale. Such information is crucial for understanding AMF ecology, and how these fungi can be used in an environmentally safe way in distant locations.

Distribution and diversity of cytotypes in Dianthus broteri as evidenced by genome size variations.

PubMed

Balao, Francisco; Casimiro-Soriguer, Ramón; Talavera, María; Herrera, Javier; Talavera, Salvador

2009-10-01

Studying the spatial distribution of cytotypes and genome size in plants can provide valuable information about the evolution of polyploid complexes. Here, the spatial distribution of cytological races and the amount of DNA in Dianthus broteri, an Iberian carnation with several ploidy levels, is investigated. Sample chromosome counts and flow cytometry (using propidium iodide) were used to determine overall genome size (2C value) and ploidy level in 244 individuals of 25 populations. Both fresh and dried samples were investigated. Differences in 2C and 1Cx values among ploidy levels within biogeographical provinces were tested using ANOVA. Geographical correlations of genome size were also explored. Extensive variation in chromosomes numbers (2n = 2x = 30, 2n = 4x = 60, 2n = 6x = 90 and 2n = 12x =180) was detected, and the dodecaploid cytotype is reported for the first time in this genus. As regards cytotype distribution, six populations were diploid, 11 were tetraploid, three were hexaploid and five were dodecaploid. Except for one diploid population containing some triploid plants (2n = 45), the remaining populations showed a single cytotype. Diploids appeared in two disjunct areas (south-east and south-west), and so did tetraploids (although with a considerably wider geographic range). Dehydrated leaf samples provided reliable measurements of DNA content. Genome size varied significantly among some cytotypes, and also extensively within diploid (up to 1.17-fold) and tetraploid (1.22-fold) populations. Nevertheless, variations were not straightforwardly congruent with ecology and geographical distribution. Dianthus broteri shows the highest diversity of cytotypes known to date in the genus Dianthus. Moreover, some cytotypes present remarkable internal genome size variation. The evolution of the complex is discussed in terms of autopolyploidy, with primary and secondary contact zones.

Investigation of Coastal CDOM Distributions Using In-Situ and Remote Sensing Observations and a Predictive CDOM Fate and Transport Model

DTIC Science & Technology

2008-01-01

Effects of Combined Sea Temperature, Light, and Carbon Dioxide on Coral Bleaching , Settlement, and Growth. The First Annual Combined Effects Think Tank...well as water quality considerations such as light-limited algal growth and seagrass and coral bed sustainability. Many studies have shown that CDOM...Zepp, R. G. 2004. “Factors Influencing Geographic and Seasonal Variations in Light Exposure of Coral Assemblages in the Florida Keys”. In “The

Geographic variation in speed of seed germination in central Oregon ponderosa pine (Pinus ponderosa Dougl. ex Laws.).

Treesearch

John C. Weber; Frank C. Sorensen

1992-01-01

Variation in speed of seed germination was investigated among ponderosa pine trees representing 225 locations in central Oregon. Results suggested that at least some of the geographic variation is related to the severity of summer drought. In general, germination speed was greater in locations with shod, drought-limited growing seasons. Levels of geographic variation...

Population characteristics of DNA fingerprints in humpback whales (Megaptera novaeangliae).

PubMed

Baker, C S; Gilbert, D A; Weinrich, M T; Lambertsen, R; Calambokidis, J; McArdle, B; Chambers, G K; O'Brien, S J

1993-01-01

Humpback whales exhibit a remarkable social organization that is characterized by seasonal long-distance migration (> 10,000 km/year) between summer feeding grounds in high latitudes and winter calving and breeding grounds in tropical or near-tropical waters. All populations are currently considered endangered as a result of intensive commercial exploitation during the last 200 years. Using three hypervariable minisatellite DNA probes (33.15, 3'HVR, and M13) originally developed for studies of human genetic variation, we examined genetic variation within and among three regional subpopulations of humpback whales from the North Pacific and one from the North Atlantic oceans. Analysis of DNA extracted from skin tissues collected by biopsy darting from free-ranging whales revealed considerable variation in each subpopulation. The extent of this variation argues against a recent history of inbreeding among humpback whales as a result of nineteenth- and twentieth-century hunting. A canonical variate analysis suggested a relationship between scaled genetic distance, based on similarities of DNA fingerprints, and geographic distance (i.e., longitude of regional subpopulation). Significant categorical differences were found between the two oceanic populations using a multivariate analysis of variance (MANOVA) with a modification of the Mantel nonparametric permutation test. The relationship between DNA fingerprint similarities and geographic distance suggests that nuclear gene flow between regional subpopulations within the North Pacific is restricted by relatively low rates of migratory interchange between breeding grounds or assortative mating on common wintering grounds.

Geographic Variation in Advertisement Calls in a Tree Frog Species: Gene Flow and Selection Hypotheses

PubMed Central

Jang, Yikweon; Hahm, Eun Hye; Lee, Hyun-Jung; Park, Soyeon; Won, Yong-Jin; Choe, Jae C.

2011-01-01

Background In a species with a large distribution relative to its dispersal capacity, geographic variation in traits may be explained by gene flow, selection, or the combined effects of both. Studies of genetic diversity using neutral molecular markers show that patterns of isolation by distance (IBD) or barrier effect may be evident for geographic variation at the molecular level in amphibian species. However, selective factors such as habitat, predator, or interspecific interactions may be critical for geographic variation in sexual traits. We studied geographic variation in advertisement calls in the tree frog Hyla japonica to understand patterns of variation in these traits across Korea and provide clues about the underlying forces for variation. Methodology We recorded calls of H. japonica in three breeding seasons from 17 localities including localities in remote Jeju Island. Call characters analyzed were note repetition rate (NRR), note duration (ND), and dominant frequency (DF), along with snout-to-vent length. Results The findings of a barrier effect on DF and a longitudinal variation in NRR seemed to suggest that an open sea between the mainland and Jeju Island and mountain ranges dominated by the north-south Taebaek Mountains were related to geographic variation in call characters. Furthermore, there was a pattern of IBD in mitochondrial DNA sequences. However, no comparable pattern of IBD was found between geographic distance and call characters. We also failed to detect any effects of habitat or interspecific interaction on call characters. Conclusions Geographic variations in call characters as well as mitochondrial DNA sequences were largely stratified by geographic factors such as distance and barriers in Korean populations of H. japoinca. Although we did not detect effects of habitat or interspecific interaction, some other selective factors such as sexual selection might still be operating on call characters in conjunction with restricted gene flow. PMID:21858061

[Factors related to the use of pediatric emergency services: results from the Spanish National Health Survey].

PubMed

Expósito-Ruiz, Manuela; Sánchez-López, Juan; Ruiz-Bailén, Manuel; Rodríguez-Del Águila, María Del Mar

2017-01-01

To determine the frequency of use of Spanish pediatric emergency services, and to describe user profiles and geographic variations. Descriptive study based on data from the Spanish National Health Survey. We calculated descriptive statistics and analyzed crude and adjusted odds ratios (ORs). Thirty-five percent of the 5495 respondents had come to an emergency department in the past year, and 88.1% of them had used the services of a Spanish national health service hospital. Factors associated with higher use of emergency services were male sex of the patient, (OR, 1.202; 95% CI, 1.047-1.381), a higher educational level of parents (OR, 1.255; 95% CI, 0.983-1.603), and younger age of the child (OR, 0.909; 95% CI, 0.894-0.924). Emergency department use varied widely from one Spanish community to another. There was a positive correlation between use and the presence of a foreign-born population (ρ=0.495, P=.031). The rate of emergency department use is high in Spain. Variability between geographic areas is considerable, and some variation is explained by population characteristics.

Geographic variation in the age- and gender-specific prevalence and incidence of epilepsy: analysis of Taiwanese National Health Insurance-based data.

PubMed

Chen, Chih-Chuan; Chen, Li-Sheng; Yen, Ming-Fang; Chen, Hsiu-Hsi; Liou, Horng-Huei

2012-02-01

We studied geographic variation in age- and gender-specific prevalence and incidence of epilepsy in four different areas of Taiwan. By using large-scale, National Health Insurance (NHI)-based data from 2000-2003 in Taiwan, we identified 131,287 patients diagnosed with epilepsy (ICD code 345) receiving at least of one of 11 antiepileptic drugs (AEDs). Information on age, gender, and location were also collected. The multivariable Poisson regression analysis was used to assess the heterogeneity of the morbidity of epilepsy in different regions. External data validation was also performed to assess the accuracy of capturing epilepsy cases through our NHI data set. The age-adjusted prevalence and incidence of epilepsy were 5.85 (per 1,000) between 2000 and 2003 and 97 (per 100,000 person-years) during the follow-up time from 2001 to 2003 in Taiwan. The sensitivity and specificity of ICD-9 coding for epilepsy in the NHI data set were 83.91% and 99.83%, respectively, resulting in a slight overestimation. Male patients had a higher probability of having epilepsy than did females. East Taiwan had significantly higher prevalence and incidence than did other areas. The age-specific incidence pattern in east Taiwan was atypical in that it revealed clustering in young and middle-aged groups. Our study demonstrated geographic variation in epidemiologic patterns of epilepsy within Taiwan. The findings are informative and provide insight into the clinical management of epilepsy based on consideration of different target groups in different areas. Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.

Prevalence of dementia and major dementia subtypes in Spanish populations: A reanalysis of dementia prevalence surveys, 1990-2008

PubMed Central

de Pedro-Cuesta, Jesús; Virués-Ortega, Javier; Vega, Saturio; Seijo-Martínez, Manuel; Saz, Pedro; Rodríguez, Fernanda; Rodríguez-Laso, Angel; Reñé, Ramón; de las Heras, Susana Pérez; Mateos, Raimundo; Martínez-Martín, Pablo; Manubens, José María; Mahillo-Fernandez, Ignacio; López-Pousa, Secundino; Lobo, Antonio; Reglà, Jordi Llinàs; Gascón, Jordi; García, Francisco José; Fernández-Martínez, Manuel; Boix, Raquel; Bermejo-Pareja, Félix; Bergareche, Alberto; Benito-León, Julián; de Arce, Ana; del Barrio, José Luis

2009-01-01

Background This study describes the prevalence of dementia and major dementia subtypes in Spanish elderly. Methods We identified screening surveys, both published and unpublished, in Spanish populations, which fulfilled specific quality criteria and targeted prevalence of dementia in populations aged 70 years and above. Surveys covering 13 geographically different populations were selected (prevalence period: 1990-2008). Authors of original surveys provided methodological details of their studies through a systematic questionnaire and also raw age-specific data. Prevalence data were compared using direct adjustment and logistic regression. Results The reanalyzed study population (aged 70 year and above) was composed of Central and North-Eastern Spanish sub-populations obtained from 9 surveys and totaled 12,232 persons and 1,194 cases of dementia (707 of Alzheimer's disease, 238 of vascular dementia). Results showed high variation in age- and sex-specific prevalence across studies. The reanalyzed prevalence of dementia was significantly higher in women; increased with age, particularly for Alzheimer's disease; and displayed a significant geographical variation among men. Prevalence was lowest in surveys reporting participation below 85%, studies referred to urban-mixed populations and populations diagnosed by psychiatrists. Conclusion Prevalence of dementia and Alzheimer's disease in Central and North-Eastern Spain is higher in females, increases with age, and displays considerable geographic variation that may be method-related. People suffering from dementia and Alzheimer's disease in Spain may approach 600,000 and 400,000 respectively. However, existing studies may not be completely appropriate to infer prevalence of dementia and its subtypes in Spain until surveys in Southern Spain are conducted. PMID:19840375

Natural Variation of Model Mutant Phenotypes in Ciona intestinalis

PubMed Central

Brown, Euan R.; Leccia, Nicola I.; Squarzoni, Paola; Tarallo, Raffaella; Alfano, Christian; Caputi, Luigi; D'Ambrosio, Palmira; Daniele, Paola; D'Aniello, Enrico; D'Aniello, Salvatore; Maiella, Sylvie; Miraglia, Valentina; Russo, Monia Teresa; Sorrenti, Gerarda; Branno, Margherita; Cariello, Lucio; Cirino, Paola; Locascio, Annamaria; Spagnuolo, Antonietta; Zanetti, Laura; Ristoratore, Filomena

2008-01-01

Background The study of ascidians (Chordata, Tunicata) has made a considerable contribution to our understanding of the origin and evolution of basal chordates. To provide further information to support forward genetics in Ciona intestinalis, we used a combination of natural variation and neutral population genetics as an approach for the systematic identification of new mutations. In addition to the significance of developmental variation for phenotype-driven studies, this approach can encompass important implications in evolutionary and population biology. Methodology/Principal Findings Here, we report a preliminary survey for naturally occurring mutations in three geographically interconnected populations of C. intestinalis. The influence of historical, geographical and environmental factors on the distribution of abnormal phenotypes was assessed by means of 12 microsatellites. We identified 37 possible mutant loci with stereotyped defects in embryonic development that segregate in a way typical of recessive alleles. Local populations were found to differ in genetic organization and frequency distribution of phenotypic classes. Conclusions/Significance Natural genetic polymorphism of C. intestinalis constitutes a valuable source of phenotypes for studying embryonic development in ascidians. Correlating genetic structure and the occurrence of abnormal phenotypes is a crucial focus for understanding the selective forces that shape natural finite populations, and may provide insights of great importance into the evolutionary mechanisms that generate animal diversity. PMID:18523552

Analyzing the non-stationary space relationship of a city's degree of vegetation and social economic conditions in Shanghai, China using OLS and GWR models

NASA Astrophysics Data System (ADS)

Wang, Kejing; Zhang, Yuan; An, Youzhi; Jing, Zhuoxin; Wang, Chao

2013-09-01

With the fast urbanization process, how does the vegetation environment change in one of the most economically developed metropolis, Shanghai in East China? To answer this question, there is a pressing demand to explore the non-stationary relationship between socio-economic conditions and vegetation across Shanghai. In this study, environmental data on vegetation cover, the Normalized Difference Vegetation Index (NDVI) derived from MODIS imagery in 2003 were integrated with socio-economic data to reflect the city's vegetative conditions at the census block group level. To explore regional variations in the relationship of vegetation and socio-economic conditions, Ordinary Least Squares (OLS) and Geographically Weighted Regression (GWR) models were applied to characterize mean NDVI against three independent socio-economic variables, an urban land use ratio, Gross Domestic Product (GDP) and population density. The study results show that a considerable distinctive spatial variation exists in the relationship for each model. The GWR model has superior effects and higher precision than the OLS model at the census block group scale. So, it is more suitable to account for local effects and geographical variations. This study also indicates that unreasonable excessive urbanization, together with non-sustainable economic development, has a negative influence of vegetation vigor for some neighborhoods in Shanghai.

Variation in Nephrologist Visits to Patients on Hemodialysis across Dialysis Facilities and Geographic Locations

PubMed Central

Tan, Kelvin B.; Winkelmayer, Wolfgang C.; Chertow, Glenn M.; Bhattacharya, Jay

2013-01-01

Summary Background and objectives Geographic and other variations in medical practices lead to differences in medical costs, often without a clear link to health outcomes. This work examined variation in the frequency of physician visits to patients receiving hemodialysis to measure the relative importance of provider practice patterns (including those patterns linked to geographic region) and patient health in determining visit frequency. Design, setting, participants, & measurements This work analyzed a nationally representative 2006 database of patients receiving hemodialysis in the United States. A variation decomposition analysis of the relative importance of facility, geographic region, and patient characteristics—including demographics, socioeconomic status, and indicators of health status—in explaining physician visit frequency variation was conducted. Finally, the associations between facility, geographic and patient characteristics, and provider visit frequency were measured using multivariable regression. Results Patient characteristics accounted for only 0.9% of the total visit frequency variation. Accounting for case-mix differences, patients’ hemodialysis facilities explained about 24.9% of visit frequency variation, of which 9.3% was explained by geographic region. Visit frequency was more closely associated with many facility and geographic characteristics than indicators of health status. More recent dialysis initiation and recent hospitalization were associated with decreased visit frequency. Conclusions In hemodialysis, provider visit frequency depends more on geography and facility location and characteristics than patients’ health status or acuity of illness. The magnitude of variation unrelated to patient health suggests that provider visit frequency practices do not reflect optimal management of patients on dialysis. PMID:23430207

Geographical Variation in Egg Mass and Egg Content in a Passerine Bird

PubMed Central

Ruuskanen, Suvi; Siitari, Heli; Eeva, Tapio; Belskii, Eugen; Järvinen, Antero; Kerimov, Anvar; Krams, Indrikis; Moreno, Juan; Morosinotto, Chiara; Mänd, Raivo; Möstl, Erich; Orell, Markku; Qvarnström, Anna; Salminen, Juha-Pekka; Slater, Fred; Tilgar, Vallo; Visser, Marcel E.; Winkel, Wolfgang; Zang, Herwig; Laaksonen, Toni

2011-01-01

Reproductive, phenotypic and life-history traits in many animal and plant taxa show geographic variation, indicating spatial variation in selection regimes. Maternal deposition to avian eggs, such as hormones, antibodies and antioxidants, critically affect development of the offspring, with long-lasting effects on the phenotype and fitness. Little is however known about large-scale geographical patterns of variation in maternal deposition to eggs. We studied geographical variation in egg components of a passerine bird, the pied flycatcher (Ficedula hypoleuca), by collecting samples from 16 populations and measuring egg and yolk mass, albumen lysozyme activity, yolk immunoglobulins, yolk androgens and yolk total carotenoids. We found significant variation among populations in most egg components, but ca. 90% of the variation was among individuals within populations. Population however explained 40% of the variation in carotenoid levels. In contrast to our hypothesis, we found geographical trends only in carotenoids, but not in any of the other egg components. Our results thus suggest high within-population variation and leave little scope for local adaptation and genetic differentiation in deposition of different egg components. The role of these maternally-derived resources in evolutionary change should be further investigated. PMID:22110579

Population Genetic Structure and Colonisation History of the Tool-Using New Caledonian Crow

PubMed Central

Abdelkrim, Jawad; Hunt, Gavin R.; Gray, Russell D.; Gemmell, Neil J.

2012-01-01

New Caledonian crows exhibit considerable variation in tool making between populations. Here, we present the first study of the species’ genetic structure over its geographical distribution. We collected feathers from crows on mainland Grande Terre, the inshore island of Toupéti, and the nearby island of Maré where it is believed birds were introduced after European colonisation. We used nine microsatellite markers to establish the genotypes of 136 crows from these islands and classical population genetic tools as well as Approximate Bayesian Computations to explore the distribution of genetic diversity. We found that New Caledonian crows most likely separate into three main distinct clusters: Grande Terre, Toupéti and Maré. Furthermore, Toupéti and Maré crows represent a subset of the genetic diversity observed on Grande Terre, confirming their mainland origin. The genetic data are compatible with a colonisation of Maré taking place after European colonisation around 1900. Importantly, we observed (1) moderate, but significant, genetic differentiation across Grande Terre, and (2) that the degree of differentiation between populations on the mainland increases with geographic distance. These data indicate that despite individual crows’ potential ability to disperse over large distances, most gene flow occurs over short distances. The temporal and spatial patterns described provide a basis for further hypothesis testing and investigation of the geographical variation observed in the tool skills of these crows. PMID:22590576

I. Sexual, individual, and geographical variation in leucosticte tephrocotis, II.Geographical variation among North American mammals, especially in respect to size

USGS Publications Warehouse

Allen, J.A.

1876-01-01

Having recently had an opportunity (through the kindness of Professor Baird) of studying with some care the magnificent series of skulls of the North American Mammalia belonging to the National Museum (amounting often to eighty or a hundred specimens of a single species), I have been strongly impressed with the different degrees of variability exhibited by the representatives of the species and genera of even the same family. The variation in size, for instance, with latitude, in the Wolves and Foxes is surprisingly great, amounting in some species (as will be shown later) to 25 per cent. of the average size of the species, while in other species of the Ferae it is almost nil. Contrary to the general supposition, the variation in size among representatives of the same species is not always a decrease with the decrease of the latitude of the locality, but is in some cases exactly the reverse, in some species there being a very considerable and indisputable increase southward. This, for instance, is very markedly true of some species of Felis and in Procyon lotor. Consequently, the very generally-received impression that in North America the species of Mammalia diminish in size southward, or with the decrease in the latitude (and altitude) of the locality, requires modification. While such is generally the case, the reverse of this too often occurs, with occasional instances also of a total absence of variation in size with locality, to be considered as forming "the exceptions" necessary to "prove the rule".

Ethnic variations in lung cancer.

PubMed

Groeger, A M; Mueller, M R; Odocha, O; Dekan, G; Salat, A; Röthy, W; Esposito, V; Caputi, M; Wolner, E; Kaiser, H E

1997-01-01

Cancer of the lung is the most frequent cancer in the world, but with wide geographical variation in risk. It is most spread among males of all races worldwide, the only exception being its incidence among Chinese women aged 70 years and older. When comparing the different ethnic groups we have to consider that besides inhaling cigarette smoke actively or as a passive smoker the exposure to occupational carcinogens varies considerably according to different work places. In our study we compared 10 years of data from African-Americans in Howard University Hospital, Washington D.C. with 20 years of data from the white population in the University Hospital of Vienna, Austria. Ethnic patterns are generally consistent within each group in terms of both incidence and mortality. The difference in susceptibility between the sexes, the three major racial groups and already proven differences in genetic variations indicate the difference between individuals concerning the initiation and progression of lung cancer.

Sex, race, and consideration of bariatric surgery among primary care patients with moderate to severe obesity.

PubMed

Wee, Christina C; Huskey, Karen W; Bolcic-Jankovic, Dragana; Colten, Mary Ellen; Davis, Roger B; Hamel, Marybeth

2014-01-01

Bariatric surgery is one of few obesity treatments to produce substantial weight loss but only a small proportion of medically-eligible patients, especially men and racial minorities, undergo bariatric surgery. To describe primary care patients' consideration of bariatric surgery, potential variation by sex and race, and factors that underlie any variation. Telephone interview of 337 patients with a body mass index or BMI > 35 kg/m(2) seen at four diverse primary care practices in Greater-Boston. Patients' consideration of bariatric surgery. Of 325 patients who had heard of bariatric surgery, 34 % had seriously considered surgery. Men were less likely than women and African Americans were less likely than Caucasian patients to have considered surgery after adjustment for sociodemographics and BMI. Comorbid conditions did not explain sex and racial differences but racial differences dissipated after adjustment for quality of life (QOL), which tended to be higher among African American than Caucasian patients. Physician recommendation of bariatric surgery was independently associated with serious consideration for surgery [OR 4.95 (95 % CI 2.81-8.70)], but did not explain variation in consideration of surgery across sex and race. However, if recommended by their doctor, men were as willing and African American and Hispanic patients were more willing to consider bariatric surgery than their respective counterparts after adjustment. Nevertheless, only 20 % of patients reported being recommended bariatric surgery by their doctor and African Americans and men were less likely to receive this recommendation; racial differences in being recommended surgery were also largely explained by differences in QOL. High perceived risk to bariatric surgery was the most commonly cited barrier; financial concerns were uncommonly cited. Single geographic region; examined consideration and not who eventually proceeded with bariatric surgery. African Americans and men were less likely to have considered bariatric surgery and were less likely to have been recommended surgery by their doctors. Differences in how obesity affects QOL appear to account for some of these variations. High perceived risk rather than financial barrier was the major deterrent for patients.

Geographic variation in health insurance benefits in Qianjiang District, China: a cross-sectional study.

PubMed

Wu, Yue; Zhang, Liang; Liu, Xuejiao; Ye, Ting; Wang, Yongfei

2018-02-05

Health insurance contributes to reducing the economic burden of disease and improving access to healthcare. In 2016, the Chinese government announced the integration of the New Cooperative Medical Scheme (NCMS) and Urban Resident Basic Medical Insurance (URBMI) to reduce system segmentation. Nevertheless, it was unclear whether there would be any geographic variation in health insurance benefits if the two types of insurance were integrated. The aim of this study was to identify the potential geographic variation in health insurance benefits and the related contributing factors. This cross-sectional study was carried out in Qianjiang District, where the NCMS and URBMI were integrated into Urban and Rural Resident Basic Medical Insurance Scheme (URRBMI) in 2010. All beneficiaries under the URRBMI were hospitalized at least once in 2013, totaling 445,254 persons and 65,877 person-times, were included in this study. Town-level data on health insurance benefits, healthcare utilization, and socioeconomic and geographical characteristics were collected through health insurance system, self-report questionnaires, and the 2014 Statistical Yearbook of Qianjiang District. A simplified Theil index at town level was calculated to measure geographic variation in health insurance benefits. Colored maps were created to visualize the variation in geographic distribution of benefits. The effects of healthcare utilization and socioeconomic and geographical characteristics on geographic variation in health insurance benefits were estimated with a multiple linear regression analysis. Different Theil index values were calculated for different towns, and the Theil index values for compensation by person-times and amount were 2.5028 and 1.8394 in primary healthcare institutions and 1.1466 and 0.9204 in secondary healthcare institutions. Healthcare-seeking behavior and economic factors were positively associated with health insurance benefits in compensation by person-times significantly, meanwhile, geographical accessibility and economic factors had positive effects (p < 0.05). The geographic variation in health insurance benefits widely existed in Qianjiang District and the distribution of health insurance benefits for insured inpatients in primary healthcare institutions was distinctly different from that in secondary healthcare institutions. When combining the NRCM and URMIS in China, the geographical accessibility, healthcare-seeking behavior and economic factors required significant attention.

[Genetic variation of geographical provenance of Pinus massoniana--review and analysis].

PubMed

Li, D; Peng, S

2000-04-01

Pinus massoniana is a significant tree species constituting the subtropical forests in China. Based on morphological, physio-ecological, chromosome, and molecular levels, the genetic variation of geographical provenance of P. massoniana and its distribution were reviewed, and the methodologies on genetic diversity and the genetic variation patterns of geographical provenance of P. massoniana were synthetically analyzed. The Key problems on molecular ecology of P. massoniana were discussed.

Sizing ocean giants: patterns of intraspecific size variation in marine megafauna

PubMed Central

Balk, Meghan A.; Benfield, Mark C.; Branch, Trevor A.; Chen, Catherine; Cosgrove, James; Dove, Alistair D.M.; Gaskins, Lindsay C.; Helm, Rebecca R.; Hochberg, Frederick G.; Lee, Frank B.; Marshall, Andrea; McMurray, Steven E.; Schanche, Caroline; Stone, Shane N.; Thaler, Andrew D.

2015-01-01

What are the greatest sizes that the largest marine megafauna obtain? This is a simple question with a difficult and complex answer. Many of the largest-sized species occur in the world’s oceans. For many of these, rarity, remoteness, and quite simply the logistics of measuring these giants has made obtaining accurate size measurements difficult. Inaccurate reports of maximum sizes run rampant through the scientific literature and popular media. Moreover, how intraspecific variation in the body sizes of these animals relates to sex, population structure, the environment, and interactions with humans remains underappreciated. Here, we review and analyze body size for 25 ocean giants ranging across the animal kingdom. For each taxon we document body size for the largest known marine species of several clades. We also analyze intraspecific variation and identify the largest known individuals for each species. Where data allows, we analyze spatial and temporal intraspecific size variation. We also provide allometric scaling equations between different size measurements as resources to other researchers. In some cases, the lack of data prevents us from fully examining these topics and instead we specifically highlight these deficiencies and the barriers that exist for data collection. Overall, we found considerable variability in intraspecific size distributions from strongly left- to strongly right-skewed. We provide several allometric equations that allow for estimation of total lengths and weights from more easily obtained measurements. In several cases, we also quantify considerable geographic variation and decreases in size likely attributed to humans. PMID:25649000

Geographic variation in cancer-related imaging: Veterans Affairs health care system versus Medicare.

PubMed

McWilliams, J Michael; Dalton, Jesse B; Landrum, Mary Beth; Frakt, Austin B; Pizer, Steven D; Keating, Nancy L

2014-12-02

Geographic variations in use of medical services have been interpreted as indirect evidence of wasteful care. Less overuse of services, however, may not be reliably associated with less geographic variation. To compare average use and geographic variation in use of cancer-related imaging between fee-for-service Medicare and the Department of Veterans Affairs (VA) health care system. Observational analysis of cancer-related imaging from 2003 to 2005 using Medicare and VA utilization data linked to cancer registry data. Multilevel models, adjusted for sociodemographic and tumor characteristics, were used to estimate mean differences in annual imaging use between cohorts of Medicare and VA patients within geographic areas and variation in use across areas for each cohort. 40 hospital referral regions. Older men with lung, colorectal, or prostate cancer, including 34,475 traditional Medicare beneficiaries (Medicare cohort) and 6835 VA patients (VA cohort). Per-patient count of imaging studies for which lung, colorectal, or prostate cancer was the primary diagnosis (each study weighted by a standardized price), and a direct measure of overuse-advanced imaging for prostate cancer at low risk for metastasis. Adjusted annual use of cancer-related imaging was lower in the VA cohort than in the Medicare cohort (price-weighted count, $197 vs. $379 per patient; P < 0.001), as was annual use of advanced imaging for prostate cancer at low risk for metastasis ($41 vs. $117 per patient; P < 0.001). Geographic variation in cancer-related imaging use was similar in magnitude in the VA and Medicare cohorts. Observational study design. Use of cancer-related imaging was lower in the VA health care system than in fee-for-service Medicare, but lower use was not associated with less geographic variation. Geographic variation in service use may not be a reliable indicator of the extent of overuse. Doris Duke Charitable Foundation and Department of Veterans Affairs Office of Policy and Planning.

Distribution and diversity of cytotypes in Dianthus broteri as evidenced by genome size variations

PubMed Central

Balao, Francisco; Casimiro-Soriguer, Ramón; Talavera, María; Herrera, Javier; Talavera, Salvador

2009-01-01

Background and Aims Studying the spatial distribution of cytotypes and genome size in plants can provide valuable information about the evolution of polyploid complexes. Here, the spatial distribution of cytological races and the amount of DNA in Dianthus broteri, an Iberian carnation with several ploidy levels, is investigated. Methods Sample chromosome counts and flow cytometry (using propidium iodide) were used to determine overall genome size (2C value) and ploidy level in 244 individuals of 25 populations. Both fresh and dried samples were investigated. Differences in 2C and 1Cx values among ploidy levels within biogeographical provinces were tested using ANOVA. Geographical correlations of genome size were also explored. Key Results Extensive variation in chromosomes numbers (2n = 2x = 30, 2n = 4x = 60, 2n = 6x = 90 and 2n = 12x =180) was detected, and the dodecaploid cytotype is reported for the first time in this genus. As regards cytotype distribution, six populations were diploid, 11 were tetraploid, three were hexaploid and five were dodecaploid. Except for one diploid population containing some triploid plants (2n = 45), the remaining populations showed a single cytotype. Diploids appeared in two disjunct areas (south-east and south-west), and so did tetraploids (although with a considerably wider geographic range). Dehydrated leaf samples provided reliable measurements of DNA content. Genome size varied significantly among some cytotypes, and also extensively within diploid (up to 1·17-fold) and tetraploid (1·22-fold) populations. Nevertheless, variations were not straightforwardly congruent with ecology and geographical distribution. Conclusions Dianthus broteri shows the highest diversity of cytotypes known to date in the genus Dianthus. Moreover, some cytotypes present remarkable internal genome size variation. The evolution of the complex is discussed in terms of autopolyploidy, with primary and secondary contact zones. PMID:19633312

Locating Spatial Variation in the Association Between Wildland Fire Risk and Social Vulnerability Across Six Southern States

NASA Astrophysics Data System (ADS)

Poudyal, Neelam C.; Johnson-Gaither, Cassandra; Goodrick, Scott; Bowker, J. M.; Gan, Jianbang

2012-03-01

Wildland fire in the South commands considerable attention, given the expanding wildland urban interface (WUI) across the region. Much of this growth is propelled by higher income retirees and others desiring natural amenity residential settings. However, population growth in the WUI increases the likelihood of wildfire fire ignition caused by people, as humans account for 93% of all wildfires fires in the South. Coexisting with newly arrived, affluent WUI populations are working class, poor or otherwise socially vulnerable populations. The latter groups typically experience greater losses from environmental disasters such as wildfire because lower income residents are less likely to have established mitigation programs in place to help absorb loss. We use geographically weighted regression to examine spatial variation in the association between social vulnerability (SOVUL) and wildfire risk. In doing so, we identify "hot spots" or geographical clusters where SOVUL varies positively with wildfire risk across six Southern states—Alabama, Arkansas, Florida, Georgia, Mississippi, and South Carolina. These clusters may or may not be located in the WUI. These hot spots are most prevalent in South Carolina and Florida. Identification of these population clusters can aid wildfire managers in deciding which communities to prioritize for mitigation programming.

Geographical variations in bacterial communities associated with soft coral Scleronephthya gracillimum.

PubMed

Woo, Seonock; Yang, Shan-Hua; Chen, Hsing-Ju; Tseng, Yu-Fang; Hwang, Sung-Jin; De Palmas, Stephane; Denis, Vianney; Imahara, Yukimitsu; Iwase, Fumihito; Yum, Seungshic; Tang, Sen-Lin

2017-01-01

Environmental impacts can alter relationships between a coral and its symbiotic microbial community. Furthermore, changes in the microbial community associated with increased seawater temperatures can cause opportunistic infections, coral disease and death. Interactions between soft corals and their associated microbes are not well understood. The species Scleronephthya gracillimum is distributed in tropical to temperate zones in coral assemblages along the Kuroshio Current region. In this study we collected S. gracillimum from various sites at different latitudes, and compared composition of their bacterial communities using Next Generation Sequencing. Coral samples from six geographically distinct areas (two sites each in Taiwan, Japan, and Korea) had considerable variation in their associated bacterial communities and diversity. Endozoicimonaceae was the dominant group in corals from Korea and Japan, whereas Mycoplasma was dominant in corals from Taiwan corals. Interestingly, the latter corals had lower relative abundance of Endozoicimonaceae, but greater diversity. These biogeographic differences in bacterial composition may have been due to varying environmental conditions among study locations, or because of host responses to prevailing environmental conditions. This study provided a baseline for future studies of soft coral microbiomes, and assessment of functions of host metabolites and soft coral holobionts.

Geographical variations in bacterial communities associated with soft coral Scleronephthya gracillimum

PubMed Central

Chen, Hsing-Ju; Tseng, Yu-Fang; Hwang, Sung-Jin; De Palmas, Stephane; Denis, Vianney; Imahara, Yukimitsu; Iwase, Fumihito; Yum, Seungshic; Tang, Sen-Lin

2017-01-01

Environmental impacts can alter relationships between a coral and its symbiotic microbial community. Furthermore, changes in the microbial community associated with increased seawater temperatures can cause opportunistic infections, coral disease and death. Interactions between soft corals and their associated microbes are not well understood. The species Scleronephthya gracillimum is distributed in tropical to temperate zones in coral assemblages along the Kuroshio Current region. In this study we collected S. gracillimum from various sites at different latitudes, and compared composition of their bacterial communities using Next Generation Sequencing. Coral samples from six geographically distinct areas (two sites each in Taiwan, Japan, and Korea) had considerable variation in their associated bacterial communities and diversity. Endozoicimonaceae was the dominant group in corals from Korea and Japan, whereas Mycoplasma was dominant in corals from Taiwan corals. Interestingly, the latter corals had lower relative abundance of Endozoicimonaceae, but greater diversity. These biogeographic differences in bacterial composition may have been due to varying environmental conditions among study locations, or because of host responses to prevailing environmental conditions. This study provided a baseline for future studies of soft coral microbiomes, and assessment of functions of host metabolites and soft coral holobionts. PMID:28859111

Sociodemographic and health characteristics, rather than primary care supply, are major drivers of geographic variation in preventable hospitalizations in Australia.

PubMed

Falster, Michael O; Jorm, Louisa R; Douglas, Kirsty A; Blyth, Fiona M; Elliott, Robert F; Leyland, Alastair H

2015-05-01

Geographic rates of preventable hospitalization are used internationally as an indicator of accessibility and quality of primary care. Much research has correlated the indicator with the supply of primary care services, yet multiple other factors may influence these admissions. To quantify the relative contributions of the supply of general practitioners (GPs) and personal sociodemographic and health characteristics, to geographic variation in preventable hospitalization. Self-reported questionnaire data for 267,091 participants in the 45 and Up Study, Australia, were linked with administrative hospital data to identify preventable hospitalizations. Multilevel Poisson models, with participants clustered in their geographic area of residence, were used to explore factors that explain geographic variation in hospitalization. GP supply, measured as full-time workload equivalents, was not a significant predictor of preventable hospitalization, and explained only a small amount (2.9%) of the geographic variation in hospitalization rates. Conversely, more than one-third (36.9%) of variation was driven by the sociodemographic composition, health, and behaviors of the population. These personal characteristics explained a greater amount of the variation for chronic conditions (37.5%) than acute (15.5%) or vaccine-preventable conditions (2.4%). Personal sociodemographic and health characteristics, rather than GP supply, are major drivers of preventable hospitalization. Their contribution varies according to condition, and if used for performance comparison purposes, geographic rates of preventable hospitalization should be reported according to individual condition or potential pathways for intervention.

Sociodemographic and Health Characteristics, Rather Than Primary Care Supply, are Major Drivers of Geographic Variation in Preventable Hospitalizations in Australia

PubMed Central

Jorm, Louisa R.; Douglas, Kirsty A.; Blyth, Fiona M.; Elliott, Robert F.; Leyland, Alastair H.

2015-01-01

Background: Geographic rates of preventable hospitalization are used internationally as an indicator of accessibility and quality of primary care. Much research has correlated the indicator with the supply of primary care services, yet multiple other factors may influence these admissions. Objective: To quantify the relative contributions of the supply of general practitioners (GPs) and personal sociodemographic and health characteristics, to geographic variation in preventable hospitalization. Methods: Self-reported questionnaire data for 267,091 participants in the 45 and Up Study, Australia, were linked with administrative hospital data to identify preventable hospitalizations. Multilevel Poisson models, with participants clustered in their geographic area of residence, were used to explore factors that explain geographic variation in hospitalization. Results: GP supply, measured as full-time workload equivalents, was not a significant predictor of preventable hospitalization, and explained only a small amount (2.9%) of the geographic variation in hospitalization rates. Conversely, more than one-third (36.9%) of variation was driven by the sociodemographic composition, health, and behaviors of the population. These personal characteristics explained a greater amount of the variation for chronic conditions (37.5%) than acute (15.5%) or vaccine-preventable conditions (2.4%). Conclusions: Personal sociodemographic and health characteristics, rather than GP supply, are major drivers of preventable hospitalization. Their contribution varies according to condition, and if used for performance comparison purposes, geographic rates of preventable hospitalization should be reported according to individual condition or potential pathways for intervention. PMID:25793270

Geographic origin is not supported by the genetic variability found in a large living collection of Jatropha curcas with accessions from three continents

PubMed Central

Maghuly, Fatemeh; Jankowicz-Cieslak, Joanna; Pabinger, Stephan; Till, Bradley J; Laimer, Margit

2015-01-01

Increasing economic interest in Jatropha curcas requires a major research focus on the genetic background and geographic origin of this non-edible biofuel crop. To determine the worldwide genetic structure of this species, amplified fragment length polymorphisms, inter simple sequence repeats, and novel single nucleotide polymorphisms (SNPs) were employed for a large collection of 907 J. curcas accessions and related species (RS) from three continents, 15 countries and 53 regions. PCoA, phenogram, and cophenetic analyses separated RS from two J. curcas groups. Accessions from Mexico, Bolivia, Paraguay, Kenya, and Ethiopia with unknown origins were found in both groups. In general, there was a considerable overlap between individuals from different regions and countries. The Bayesian approach using structure demonstrated two groups with a low genetic variation. Analysis of molecular varience revealed significant variation among individuals within populations. SNPs found by in silico analyses of Δ12 fatty acid desaturase indicated possible changes in gene expression and thus in fatty acid profiles. SNP variation was higher in the curcin gene compared to genes involved in oil production. Novel SNPs allowed separating toxic, non-toxic, and Mexican accessions. The present study confirms that human activities had a major influence on the genetic diversity of J. curcas, not only because of domestication, but also because of biased selection. PMID:25511658

Brief Report: Geographical Variation in Prevalence of Cryptococcal Antigenemia Among HIV-Infected, Treatment-Naive Patients in Nigeria: A Multicenter Cross-Sectional Study.

PubMed

Ezeanolue, Echezona E; Nwizu, Chidi; Greene, Gregory S; Amusu, Olatilewa; Chukwuka, Chinwe; Ndembi, Nicaise; Smith, Rachel M; Chiller, Tom; Pharr, Jennifer; Kozel, Thomas R

2016-09-01

Worldwide, HIV-associated cryptococcal meningitis affects approximately 1 million persons and causes 600,000 deaths each year mostly in sub-Saharan Africa. Limited data exist on cryptococcal meningitis and antigenemia in Nigeria, and most studies are geographically restricted. We determined the prevalence of cryptococcal antigenemia (CrAg) among HIV-infected, treatment-naive individuals in Nigeria. This was a retrospective, cross-sectional study across 4 geographic regions in Nigeria. We performed CrAg testing using a lateral flow immunoassay on archived whole-blood samples collected from HIV-infected participants at US President's Emergency Plan for AIDS Relief (PEPFAR)-supported sites selected to represent the major geographical and ethnic diversity in Nigeria. Eligible samples were collected from consenting patients (>15 years) naive to antiretroviral therapy with CD4 count less than 200 cells per cubic millimeter and were stored in an -80°C freezer. A total of 2752 stored blood samples were retrospectively screened for CrAg. Most of the samples were from participants aged 30-44 years (57.6%), and 1570 (57.1%) were from women. The prevalence of CrAg positivity in specimens with CD4 <200 cells per cubic millimeter was 2.3% (95% confidence interval: 1.8% to 3.0%) and varied significantly across the 4 regions (P < 0.001). At 4.4% (3.2% to 5.9%), the South East contained the highest prevalence. The significant regional variation in CrAg prevalence found in Nigeria should be taken into consideration as plans are made to integrate routine screening into clinical care for HIV-infected patients.

Geographical Variation in Prevalence of Cryptococcal Antigenemia among HIV-infected Treatment-Naïve Patients in Nigeria: A multicenter cross-sectional study

PubMed Central

Ezeanolue, Echezona E.; Nwizu, Chidi; Greene, Gregory S.; Amusu, Olatilewa; Chukwuka, Chinwe; Ndembi, Nicaise; Smith, Rachel M.; Chiller, Tom; Pharr, Jennifer; Kozel, Thomas R

2016-01-01

Objective Worldwide, HIV-associated cryptococcal meningitis affects approximately 1 million persons and causes 600,000 deaths each year mostly in sub-Sharan Africa. Limited data exist on cryptococcal meningitis and antigenemia in Nigeria, and most studies are geographically restricted. We determined the prevalence of cryptococcal antigenemia (CrAg) among HIV-infected treatment-naïve individuals in Nigeria. Design/Methods This was a retrospective, cross-sectional study across four geographic regions in Nigeria. We performed CrAg testing using a lateral flow immunoassay on archived whole blood samples collected from HIV-infected participants at US PEPFAR-supported sites selected to represent the major geographical and ethnic diversity in Nigeria. Eligible samples were (1) stored in an -80° freezer; (2) collected from consenting patients (>15 years) naïve to antiretroviral therapy with CD4+ count less than 200 cells/mm3. Results A total of 2,752 stored blood samples were retrospectively screened for CrAg. A majority of samples were from participants aged 30 - 44 (57.6%), and 1,570 (57.1%) were from women. The prevalence of CrAg positivity in specimens with CD4 < 200 cells/mm3 was 2.3% (95% CI = 1.8%-3.0%), and varied significantly across the four regions (p < 0.001). At 4.4% (3.2%-5.9%), the South East contained the highest prevalence. Conclusion The significant regional variation in CrAg prevalence found in Nigeria should be taken into consideration as plans are made to integrate routine screening into clinical care for HIV-infected patients. PMID:27144527

Geographic variation in colorectal cancer survival and the role of small-area socioeconomic deprivation: a multilevel survival analysis of the NIH-AARP Diet and Health Study Cohort.

PubMed

Lian, Min; Schootman, Mario; Doubeni, Chyke A; Park, Yikyung; Major, Jacqueline M; Stone, Rosalie A Torres; Laiyemo, Adeyinka O; Hollenbeck, Albert R; Graubard, Barry I; Schatzkin, Arthur

2011-10-01

Adverse socioeconomic conditions, at both the individual and the neighborhood level, increase the risk of colorectal cancer (CRC) death, but little is known regarding whether CRC survival varies geographically and the extent to which area-level socioeconomic deprivation affects this geographic variation. Using data from the National Institutes of Health (NIH)-AARP Diet and Health Study, the authors examined geographic variation and the role of area-level socioeconomic deprivation in CRC survival. CRC cases (n = 7,024), identified during 1995-2003, were followed for their CRC-specific vital status through 2005 and overall vital status through 2006. Bayesian multilevel survival models showed that there was significant geographic variation in overall (variance = 0.2, 95% confidence interval (CI): 0.1, 0.2) and CRC-specific (variance = 0.3, 95% CI: 0.1, 0.4) risk of death. More socioeconomically deprived neighborhoods had a higher overall risk of death (most deprived quartile vs. least deprived: hazard ratio = 1.2, 95% CI: 1.1, 1.4) and a higher CRC-specific risk of death (most deprived quartile vs. least deprived: hazard ratio = 1.2, 95% CI: 1.1, 1.5). However, neighborhood socioeconomic deprivation did not account for the geographic variation in overall and CRC-specific risks of death. In future studies, investigators should evaluate other neighborhood characteristics to help explain geographic heterogeneity in CRC survival. Such research could facilitate interventions for reducing geographic disparity in CRC survival.

Life-cycle thinking and the LEED rating system: global perspective on building energy use and environmental impacts.

PubMed

Al-Ghamdi, Sami G; Bilec, Melissa M

2015-04-07

This research investigates the relationship between energy use, geographic location, life cycle environmental impacts, and Leadership in Energy and Environmental Design (LEED). The researchers studied worldwide variations in building energy use and associated life cycle impacts in relation to the LEED rating systems. A Building Information Modeling (BIM) of a reference 43,000 ft(2) office building was developed and situated in 400 locations worldwide while making relevant changes to the energy model to meet reference codes, such as ASHRAE 90.1. Then life cycle environmental and human health impacts from the buildings' energy consumption were calculated. The results revealed considerable variations between sites in the U.S. and international locations (ranging from 394 ton CO2 equiv to 911 ton CO2 equiv, respectively). The variations indicate that location specific results, when paired with life cycle assessment, can be an effective means to achieve a better understanding of possible adverse environmental impacts as a result of building energy consumption in the context of green building rating systems. Looking at these factors in combination and using a systems approach may allow rating systems like LEED to continue to drive market transformation toward sustainable development, while taking into consideration both energy sources and building efficiency.

Advancing the Hypothesis that Geographic Variations in Risk Factors Contribute Relatively Little to Observed Geographic Variations in Heart Disease and Stroke Mortality

PubMed Central

Howard, George; Cushman, Mary; Prineas, Ronald J.; Howard, Virginia J.; Moy, Claudia S.; Sullivan, Lisa M.; D’Agostino, Ralph B.; McClure, Leslie A.; Pulley, Lea Vonne; Safford, Monika M.

2009-01-01

Purpose Geographic variation in risk factors may underlie geographic disparities in coronary heart disease (CHD) and stroke mortality. Methods Framingham CHD Risk Score (FCRS) and Stroke Risk Score (FSRS) were calculated for 25,770 stroke-free and 22,247 CHD-free participants from the REasons for Geographic And Racial Differences in Stroke cohort. Vital statistics provided age-adjusted CHD and stroke mortality rates. In an ecologic analysis, the age-adjusted, race-sex weighted, average state-level risk factor levels were compared to state-level mortality rates. Results There was no relationship between CHD and stroke mortality rates (r = 0.04; p = 0.78), but there was between CHD and stroke risk scores at the individual (r = 0.68; p < 0.0001) and state (r = 0.64, p < 0.0001) level. There was a stronger (p < 0.0001) association between state-level FCRS and state-level CHD mortality (r = 0.28, p = 0.18), than between FSRS and stroke mortality (r = 0.12, p = 0.56). Conclusions Weak associations between CHD and stroke mortality and strong associations between CHD and stroke risk scores suggest geographic variation in risk factors may not underlie geographic variations in stroke and CHD mortality. The relationship between risk factor scores and mortality was stronger for CHD than stroke. PMID:19285103

Geographic variation in foraging ecologies of breeding and nonbreeding birds in oak woodlands

Treesearch

William M. Block

1990-01-01

I studied geographic variation in the foraging ecology of four breeding and four non breeding species in three oak (Quercus spp.) woodlands of California. Variations were evident for all species. Variations in tree-species use, foraging tactics, substrates, and behaviors were species-specific. For example, White-breasted Nuthatches (Sitta carolinensis) used...

Do experiences with pregnancy, birth and postnatal care in Norway vary by the women's geographic origin? a comparison of cross-sectional survey results.

PubMed

Sjetne, Ingeborg S; Iversen, Hilde H

2017-01-18

A national survey was conducted to measure and benchmark women's experiences with pregnancy, birth and postnatal care in Norway. The purpose of this secondary analysis is to explore potential variation in these experiences with regard to the survey respondents' geographic origin. Data were collected in a national observational cross-sectional study, by a self-administered questionnaire and from registries. The questionnaire collects patient reported experience measures (PREMS) of mainly nontechnical aspects of the health-care services. While taking the clustered characteristics of the respondents into consideration, we compared the mean scores on 16 indexes between women of four different geographic origins using linear regression models. The origin of the 4904 respondents were classified as Norway (n = 4028, 82%), Western Europe, North-America, Oceania (n = 233, 5%), Eastern Europe (n = 290, 6%), and Asia, Turkey, Africa, and South-America) (n = 353, 7%). The observed differences were moderate, and no consistency was present in the results in respect of direction or magnitude of the differences between the groups. With some important cautions, we conclude that this study did not detect systematic differences between groups of different geographic origin, in their experiences with pregnancy and maternity care in Norway.

Population Explosion in the Yellow-Spined Bamboo Locust Ceracris kiangsu and Inferences for the Impact of Human Activity

PubMed Central

Fan, Zhou; Jiang, Guo-Fang; Liu, Yu-Xiang; He, Qi-Xin; Blanchard, Benjamin

2014-01-01

Geographic distance and geographical barriers likely play a considerable role in structuring genetic variation in species, although some migratory species may have less phylogeographic structure on a smaller spatial scale. Here, genetic diversity and the phylogenetic structure among geographical populations of the yellow-spined bamboo locust, Ceracris kiangsu, were examined with 16S rDNA and amplified fragment length polymorphisms (AFLPs). In this study, no conspicuous phylogeographical structure was discovered from either Maximum parsimony (MP) and Neighbor-joining (NJ) phylogenetic analyses. The effect of geographical isolation was not conspicuous on a large spatial scale.At smaller spatial scales local diversity of some populations within mountainous areas were detected using Nei's genetic distance and AMOVA. There is a high level of genetic diversity and a low genetic differentiation among populations in the C. kiangsu of South and Southeast China. Our analyses indicate that C. kiangsu is a monophyletic group. Our results also support the hypothesis that the C. kiangsu population is in a primary differentiation stage. Given the mismatch distribution, it is likely that a population expansion in C. kiangsu occurred about 0.242 Ma during the Quaternary interglaciation. Based on historical reports, we conjecture that human activities had significant impacts on the C. kiangsu gene flow. PMID:24603526

Geographical variation in dementia: examining the role of environmental factors in Sweden and Scotland

PubMed Central

Russ, Tom C.; Gatz, Margaret; Pedersen, Nancy L.; Hannah, Jean; Wyper, Grant; Batty, G. David; Deary, Ian J.; Starr, John M.

2015-01-01

Background This study aimed to estimate the magnitude of geographical variation in dementia rates and suggest explanations for this variation. Small-area studies are scarce, and none has adequately investigated the relative contribution of genetic and environmental factors to the distribution of dementia. Methods We present two complementary small-area hierarchical Bayesian disease mapping studies using the comprehensive Swedish Twin Registry (n=27,680) and the 1932 Scottish Mental Survey cohort (n=37,597). The twin study allowed us to isolate the area in order to examine the effect of unshared environmental factors. The Scottish Mental Survey study allowed us to examine various epochs in the life course – approximately age 11 years and adulthood. Results We found a 2-to 3- fold geographical variation in dementia odds in Sweden, after twin random effects – likely to capture genetic and shared environmental variance – were removed. In Scotland we found no variation in dementia odds in childhood but substantial variation, following a broadly similar pattern to Sweden, by adulthood. Conclusions There is geographical variation in dementia rates. Most of this variation is likely to result from unshared environmental factors that have their effect in adolescence or later. Further work is required to confirm these findings and identify any potentially modifiable socio-environmental risk factors for dementia responsible for this geographical variation in risk. However, if these factors do exist and could be optimized in the whole population, our results suggest that dementia rates could be halved. PMID:25575031

A framework for investigating geographical variation in diseases, based on a study of Legionnaires' disease.

PubMed

Bhopal, R S

1991-11-01

Demonstration of geographical variations in disease can yield powerful insight into the disease pathway, particularly for environmentally acquired conditions, but only if the many problems of data interpretation can be solved. This paper presents the framework, methods and principles guiding a study of the geographical epidemiology of Legionnaires' Disease in Scotland. A case-list was constructed and disease incidence rates were calculated by geographical area; these showed variation. Five categories of explanation for the variation were identified: short-term fluctuations of incidence in time masquerading as differences by place; artefact; and differences in host-susceptibility, agent virulence, or environment. The methods used to study these explanations, excepting agent virulence, are described, with an emphasis on the use of previously existing data to test hypotheses. Examples include the use of mortality, census and hospital morbidity data to assess the artefact and host-susceptibility explanations; and the use of ratios of serology tests to disease to examine the differential testing hypothesis. The reasoning and process by which the environmental focus of the study was narrowed and the technique for relating the geographical pattern of disease to the putative source are outlined. This framework allows the researcher to plan for the parallel collection of the data necessary both to demonstrate geographical variation and to point to the likely explanation.

Knitting the Threads of Silk through Time: Behçet's Disease—Past, Present, and Future

PubMed Central

Stack, Austin G.; Fraser, Alexander D.

2017-01-01

Behçet's disease (BD) is a chronic relapsing vasculitis that affects vessels of all types and sizes with a broad spectrum of phenotypic heterogeneity and complex immunopathogenesis. Efforts by the scientific community to resolve the unmet needs of BD and gaps in our knowledge have been hampered by considerable challenges that primarily relate to the rare nature of the disease in many parts of the world and its heterogeneity. Controversies remain in many aspects of the disease including the diagnostic criteria, immunopathogenesis and biomarker discovery, geographical variation, and therapeutic considerations. In this review, we highlight recent advances in our scientific understanding of BD, shed new insights into diagnostic and treatment strategies, and discuss residual gaps in our knowledge that will serve as the basis for current and future research. PMID:29081805

Cancer-related Imaging in the Veterans Affairs Health Care System versus Medicare: Does a System with Lower Use Exhibit Less Geographic Variation?

PubMed Central

McWilliams, J. Michael; Dalton, Jesse B.; Landrum, Mary Beth; Frakt, Austin B.; Pizer, Steven D.; Keating, Nancy L.

2014-01-01

Background Geographic variations in use of medical services have been interpreted as indirect evidence of wasteful care. Less overuse of services, however, may not be reliably associated with less geographic variation. Objective To compare average use and geographic variation in use of cancer-related imaging between fee-for-service Medicare and the Department of Veterans Affairs (VA) health care system. Design Observational analysis of cancer-related imaging from 2003–2005, using Medicare and VA utilization data linked to cancer registry data. We used multilevel models to estimate mean differences in annual imaging use between cohorts of Medicare and VA patients within geographic areas and variation in use across areas for each cohort, adjusting for sociodemographic and tumor characteristics. Setting 40 hospital referral regions. Patients Older men with lung, colorectal, or prostate cancer, including 34,475 traditional Medicare beneficiaries (Medicare cohort) and 6,835 VA patients (VA cohort). Measurements 1)Per-patient count of imaging studies for which lung, colorectal, or prostate cancer was the primary diagnosis (each study weighted by a standardized price); 2)a direct measure of overuse—advanced imaging for prostate cancer at low risk of metastasis. Results Adjusted annual use of cancer-related imaging was lower in the VA cohort than the Medicare cohort (price-weighted count, $197 vs. $379/patient; P<0.001), as was annual use of advanced imaging for prostate cancer at low risk of metastasis ($41 vs. $117/patient; P<0.001). Geographic variation in cancer-related imaging use was similar in magnitude in the VA and Medicare cohorts. Limitations Observational study design. Conclusions Use of cancer-related imaging was lower in the VA health care system than in fee-for-service Medicare, but lower use was not associated with less geographic variation. Geographic variation in service use may not be a reliable indicator of the extent of overuse. Primary Funding Source Doris Duke Charitable Foundation and Department of Veterans Affairs Office of Policy and Planning. PMID:25437407

The beta-diversity of species interactions: Untangling the drivers of geographic variation in plant-pollinator diversity and function across scales.

PubMed

Burkle, Laura A; Myers, Jonathan A; Belote, R Travis

2016-01-01

Geographic patterns of biodiversity have long inspired interest in processes that shape the assembly, diversity, and dynamics of communities at different spatial scales. To study mechanisms of community assembly, ecologists often compare spatial variation in community composition (beta-diversity) across environmental and spatial gradients. These same patterns inspired evolutionary biologists to investigate how micro- and macro-evolutionary processes create gradients in biodiversity. Central to these perspectives are species interactions, which contribute to community assembly and geographic variation in evolutionary processes. However, studies of beta-diversity have predominantly focused on single trophic levels, resulting in gaps in our understanding of variation in species-interaction networks (interaction beta-diversity), especially at scales most relevant to evolutionary studies of geographic variation. We outline two challenges and their consequences in scaling-up studies of interaction beta-diversity from local to biogeographic scales using plant-pollinator interactions as a model system in ecology, evolution, and conservation. First, we highlight how variation in regional species pools may contribute to variation in interaction beta-diversity among biogeographic regions with dissimilar evolutionary history. Second, we highlight how pollinator behavior (host-switching) links ecological networks to geographic patterns of plant-pollinator interactions and evolutionary processes. Third, we outline key unanswered questions regarding the role of geographic variation in plant-pollinator interactions for conservation and ecosystem services (pollination) in changing environments. We conclude that the largest advances in the burgeoning field of interaction beta-diversity will come from studies that integrate frameworks in ecology, evolution, and conservation to understand the causes and consequences of interaction beta-diversity across scales. © 2016 Botanical Society of America.

The evolution of environmental tolerance and range size: a comparison of geographically restricted and widespread Mimulus.

PubMed

Sheth, Seema N; Angert, Amy L

2014-10-01

The geographic ranges of closely related species can vary dramatically, yet we do not fully grasp the mechanisms underlying such variation. The niche breadth hypothesis posits that species that have evolved broad environmental tolerances can achieve larger geographic ranges than species with narrow environmental tolerances. In turn, plasticity and genetic variation in ecologically important traits and adaptation to environmentally variable areas can facilitate the evolution of broad environmental tolerance. We used five pairs of western North American monkeyflowers to experimentally test these ideas by quantifying performance across eight temperature regimes. In four species pairs, species with broader thermal tolerances had larger geographic ranges, supporting the niche breadth hypothesis. As predicted, species with broader thermal tolerances also had more within-population genetic variation in thermal reaction norms and experienced greater thermal variation across their geographic ranges than species with narrow thermal tolerances. Species with narrow thermal tolerance may be particularly vulnerable to changing climatic conditions due to lack of plasticity and insufficient genetic variation to respond to novel selection pressures. Conversely, species experiencing high variation in temperature across their ranges may be buffered against extinction due to climatic changes because they have evolved tolerance to a broad range of temperatures. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Climatic and geographic predictors of life history variation in Eastern Massasauga (Sistrurus catenatus): A range-wide synthesis.

PubMed

Hileman, Eric T; King, Richard B; Adamski, John M; Anton, Thomas G; Bailey, Robyn L; Baker, Sarah J; Bieser, Nickolas D; Bell, Thomas A; Bissell, Kristin M; Bradke, Danielle R; Campa, Henry; Casper, Gary S; Cedar, Karen; Cross, Matthew D; DeGregorio, Brett A; Dreslik, Michael J; Faust, Lisa J; Harvey, Daniel S; Hay, Robert W; Jellen, Benjamin C; Johnson, Brent D; Johnson, Glenn; Kiel, Brooke D; Kingsbury, Bruce A; Kowalski, Matthew J; Lee, Yu Man; Lentini, Andrew M; Marshall, John C; Mauger, David; Moore, Jennifer A; Paloski, Rori A; Phillips, Christopher A; Pratt, Paul D; Preney, Thomas; Prior, Kent A; Promaine, Andrew; Redmer, Michael; Reinert, Howard K; Rouse, Jeremy D; Shoemaker, Kevin T; Sutton, Scott; VanDeWalle, Terry J; Weatherhead, Patrick J; Wynn, Doug; Yagi, Anne

2017-01-01

Elucidating how life history traits vary geographically is important to understanding variation in population dynamics. Because many aspects of ectotherm life history are climate-dependent, geographic variation in climate is expected to have a large impact on population dynamics through effects on annual survival, body size, growth rate, age at first reproduction, size-fecundity relationship, and reproductive frequency. The Eastern Massasauga (Sistrurus catenatus) is a small, imperiled North American rattlesnake with a distribution centered on the Great Lakes region, where lake effects strongly influence local conditions. To address Eastern Massasauga life history data gaps, we compiled data from 47 study sites representing 38 counties across the range. We used multimodel inference and general linear models with geographic coordinates and annual climate normals as explanatory variables to clarify patterns of variation in life history traits. We found strong evidence for geographic variation in six of nine life history variables. Adult female snout-vent length and neonate mass increased with increasing mean annual precipitation. Litter size decreased with increasing mean temperature, and the size-fecundity relationship and growth prior to first hibernation both increased with increasing latitude. The proportion of gravid females also increased with increasing latitude, but this relationship may be the result of geographically varying detection bias. Our results provide insights into ectotherm life history variation and fill critical data gaps, which will inform Eastern Massasauga conservation efforts by improving biological realism for models of population viability and climate change.

Climatic and geographic predictors of life history variation in Eastern Massasauga (Sistrurus catenatus): A range-wide synthesis

PubMed Central

King, Richard B.; Adamski, John M.; Anton, Thomas G.; Bailey, Robyn L.; Baker, Sarah J.; Bieser, Nickolas D.; Bell, Thomas A.; Bissell, Kristin M.; Bradke, Danielle R.; Campa, Henry; Casper, Gary S.; Cedar, Karen; Cross, Matthew D.; DeGregorio, Brett A.; Dreslik, Michael J.; Faust, Lisa J.; Harvey, Daniel S.; Hay, Robert W.; Jellen, Benjamin C.; Johnson, Brent D.; Johnson, Glenn; Kiel, Brooke D.; Kingsbury, Bruce A.; Kowalski, Matthew J.; Lee, Yu Man; Lentini, Andrew M.; Marshall, John C.; Mauger, David; Moore, Jennifer A.; Paloski, Rori A.; Phillips, Christopher A.; Pratt, Paul D.; Preney, Thomas; Prior, Kent A.; Promaine, Andrew; Redmer, Michael; Reinert, Howard K.; Rouse, Jeremy D.; Shoemaker, Kevin T.; Sutton, Scott; VanDeWalle, Terry J.; Weatherhead, Patrick J.; Wynn, Doug; Yagi, Anne

2017-01-01

Elucidating how life history traits vary geographically is important to understanding variation in population dynamics. Because many aspects of ectotherm life history are climate-dependent, geographic variation in climate is expected to have a large impact on population dynamics through effects on annual survival, body size, growth rate, age at first reproduction, size–fecundity relationship, and reproductive frequency. The Eastern Massasauga (Sistrurus catenatus) is a small, imperiled North American rattlesnake with a distribution centered on the Great Lakes region, where lake effects strongly influence local conditions. To address Eastern Massasauga life history data gaps, we compiled data from 47 study sites representing 38 counties across the range. We used multimodel inference and general linear models with geographic coordinates and annual climate normals as explanatory variables to clarify patterns of variation in life history traits. We found strong evidence for geographic variation in six of nine life history variables. Adult female snout-vent length and neonate mass increased with increasing mean annual precipitation. Litter size decreased with increasing mean temperature, and the size–fecundity relationship and growth prior to first hibernation both increased with increasing latitude. The proportion of gravid females also increased with increasing latitude, but this relationship may be the result of geographically varying detection bias. Our results provide insights into ectotherm life history variation and fill critical data gaps, which will inform Eastern Massasauga conservation efforts by improving biological realism for models of population viability and climate change. PMID:28196149

A BAYESIAN SPATIAL AND TEMPORAL MODELING APPROACH TO MAPPING GEOGRAPHIC VARIATION IN MORTALITY RATES FOR SUBNATIONAL AREAS WITH R-INLA.

PubMed

Khana, Diba; Rossen, Lauren M; Hedegaard, Holly; Warner, Margaret

2018-01-01

Hierarchical Bayes models have been used in disease mapping to examine small scale geographic variation. State level geographic variation for less common causes of mortality outcomes have been reported however county level variation is rarely examined. Due to concerns about statistical reliability and confidentiality, county-level mortality rates based on fewer than 20 deaths are suppressed based on Division of Vital Statistics, National Center for Health Statistics (NCHS) statistical reliability criteria, precluding an examination of spatio-temporal variation in less common causes of mortality outcomes such as suicide rates (SRs) at the county level using direct estimates. Existing Bayesian spatio-temporal modeling strategies can be applied via Integrated Nested Laplace Approximation (INLA) in R to a large number of rare causes of mortality outcomes to enable examination of spatio-temporal variations on smaller geographic scales such as counties. This method allows examination of spatiotemporal variation across the entire U.S., even where the data are sparse. We used mortality data from 2005-2015 to explore spatiotemporal variation in SRs, as one particular application of the Bayesian spatio-temporal modeling strategy in R-INLA to predict year and county-specific SRs. Specifically, hierarchical Bayesian spatio-temporal models were implemented with spatially structured and unstructured random effects, correlated time effects, time varying confounders and space-time interaction terms in the software R-INLA, borrowing strength across both counties and years to produce smoothed county level SRs. Model-based estimates of SRs were mapped to explore geographic variation.

Geographic Variation of Melanisation Patterns in a Hornet Species: Genetic Differences, Climatic Pressures or Aposematic Constraints?

PubMed Central

Perrard, Adrien; Arca, Mariangela; Rome, Quentin; Muller, Franck; Tan, Jiangli; Bista, Sanjaya; Nugroho, Hari; Baudoin, Raymond; Baylac, Michel; Silvain, Jean-François; Carpenter, James M.; Villemant, Claire

2014-01-01

Coloration of stinging insects is often based on contrasted patterns of light and black pigmentations as a warning signal to predators. However, in many social wasp species, geographic variation drastically modifies this signal through melanic polymorphism potentially driven by different selective pressures. To date, surprisingly little is known about the geographic variation of coloration of social wasps in relation to aposematism and melanism and to genetic and developmental constraints. The main objectives of this study are to improve the description of the colour variation within a social wasp species and to determine which factors are driving this variation. Therefore, we explored the evolutionary history of a polymorphic hornet, Vespa velutina Lepeletier, 1836, using mitochondrial and microsatellite markers, and we analysed its melanic variation using a colour space based on a description of body parts coloration. We found two main lineages within the species and confirmed the previous synonymy of V. auraria Smith, 1852, under V. velutina, differing only by the coloration. We also found that the melanic variation of most body parts was positively correlated, with some segments forming potential colour modules. Finally, we showed that the variation of coloration between populations was not related to their molecular, geographic or climatic differences. Our observations suggest that the coloration patterns of hornets and their geographic variations are determined by genes with an influence of developmental constraints. Our results also highlight that Vespa velutina populations have experienced several convergent evolutions of the coloration, more likely influenced by constraints on aposematism and Müllerian mimicry than by abiotic pressures on melanism. PMID:24740142

Geographic variation of melanisation patterns in a hornet species: genetic differences, climatic pressures or aposematic constraints?

PubMed

Perrard, Adrien; Arca, Mariangela; Rome, Quentin; Muller, Franck; Tan, Jiangli; Bista, Sanjaya; Nugroho, Hari; Baudoin, Raymond; Baylac, Michel; Silvain, Jean-François; Carpenter, James M; Villemant, Claire

2014-01-01

Coloration of stinging insects is often based on contrasted patterns of light and black pigmentations as a warning signal to predators. However, in many social wasp species, geographic variation drastically modifies this signal through melanic polymorphism potentially driven by different selective pressures. To date, surprisingly little is known about the geographic variation of coloration of social wasps in relation to aposematism and melanism and to genetic and developmental constraints. The main objectives of this study are to improve the description of the colour variation within a social wasp species and to determine which factors are driving this variation. Therefore, we explored the evolutionary history of a polymorphic hornet, Vespa velutina Lepeletier, 1836, using mitochondrial and microsatellite markers, and we analysed its melanic variation using a colour space based on a description of body parts coloration. We found two main lineages within the species and confirmed the previous synonymy of V. auraria Smith, 1852, under V. velutina, differing only by the coloration. We also found that the melanic variation of most body parts was positively correlated, with some segments forming potential colour modules. Finally, we showed that the variation of coloration between populations was not related to their molecular, geographic or climatic differences. Our observations suggest that the coloration patterns of hornets and their geographic variations are determined by genes with an influence of developmental constraints. Our results also highlight that Vespa velutina populations have experienced several convergent evolutions of the coloration, more likely influenced by constraints on aposematism and Müllerian mimicry than by abiotic pressures on melanism.

Estimation of geographic variation in human papillomavirus vaccine uptake in men and women: an online survey using facebook recruitment.

PubMed

Nelson, Erik J; Hughes, John; Oakes, J Michael; Pankow, James S; Kulasingam, Shalini L

2014-09-01

Federally funded surveys of human papillomavirus (HPV) vaccine uptake are important for pinpointing geographically based health disparities. Although national and state level data are available, local (ie, county and postal code level) data are not due to small sample sizes, confidentiality concerns, and cost. Local level HPV vaccine uptake data may be feasible to obtain by targeting specific geographic areas through social media advertising and recruitment strategies, in combination with online surveys. Our goal was to use Facebook-based recruitment and online surveys to estimate local variation in HPV vaccine uptake among young men and women in Minnesota. From November 2012 to January 2013, men and women were recruited via a targeted Facebook advertisement campaign to complete an online survey about HPV vaccination practices. The Facebook advertisements were targeted to recruit men and women by location (25 mile radius of Minneapolis, Minnesota, United States), age (18-30 years), and language (English). Of the 2079 men and women who responded to the Facebook advertisements and visited the study website, 1003 (48.2%) enrolled in the study and completed the survey. The average advertising cost per completed survey was US $1.36. Among those who reported their postal code, 90.6% (881/972) of the participants lived within the previously defined geographic study area. Receipt of 1 dose or more of HPV vaccine was reported by 65.6% women (351/535), and 13.0% (45/347) of men. These results differ from previously reported Minnesota state level estimates (53.8% for young women and 20.8% for young men) and from national estimates (34.5% for women and 2.3% for men). This study shows that recruiting a representative sample of young men and women based on county and postal code location to complete a survey on HPV vaccination uptake via the Internet is a cost-effective and feasible strategy. This study also highlights the need for local estimates to assess the variation in HPV vaccine uptake, as these estimates differ considerably from those obtained using survey data that are aggregated to the state or federal level.

Estimation of Geographic Variation in Human Papillomavirus Vaccine Uptake in Men and Women: An Online Survey Using Facebook Recruitment

PubMed Central

Hughes, John; Oakes, J Michael; Pankow, James S; Kulasingam, Shalini L

2014-01-01

Background Federally funded surveys of human papillomavirus (HPV) vaccine uptake are important for pinpointing geographically based health disparities. Although national and state level data are available, local (ie, county and postal code level) data are not due to small sample sizes, confidentiality concerns, and cost. Local level HPV vaccine uptake data may be feasible to obtain by targeting specific geographic areas through social media advertising and recruitment strategies, in combination with online surveys. Objective Our goal was to use Facebook-based recruitment and online surveys to estimate local variation in HPV vaccine uptake among young men and women in Minnesota. Methods From November 2012 to January 2013, men and women were recruited via a targeted Facebook advertisement campaign to complete an online survey about HPV vaccination practices. The Facebook advertisements were targeted to recruit men and women by location (25 mile radius of Minneapolis, Minnesota, United States), age (18-30 years), and language (English). Results Of the 2079 men and women who responded to the Facebook advertisements and visited the study website, 1003 (48.2%) enrolled in the study and completed the survey. The average advertising cost per completed survey was US $1.36. Among those who reported their postal code, 90.6% (881/972) of the participants lived within the previously defined geographic study area. Receipt of 1 dose or more of HPV vaccine was reported by 65.6% women (351/535), and 13.0% (45/347) of men. These results differ from previously reported Minnesota state level estimates (53.8% for young women and 20.8% for young men) and from national estimates (34.5% for women and 2.3% for men). Conclusions This study shows that recruiting a representative sample of young men and women based on county and postal code location to complete a survey on HPV vaccination uptake via the Internet is a cost-effective and feasible strategy. This study also highlights the need for local estimates to assess the variation in HPV vaccine uptake, as these estimates differ considerably from those obtained using survey data that are aggregated to the state or federal level. PMID:25231937

Spatial Variation in Body Size and Wing Dimorphism Correlates With Environmental Conditions in the Grasshopper Dichroplus vittatus (Orthoptera: Acrididae).

PubMed

Rosetti, Natalia; Remis, Maria I

2018-06-06

Wing dimorphism occurs widely in insects and involves discontinuous variation in a wide variety of traits involved in fight and reproduction. In the current study, we analyzed the spatial pattern of wing dimorphism and intraspecific morphometric variation in nine natural populations of the grasshopper Dichroplus vittatus (Bruner; Orthoptera: Acrididae) in Argentina. Considerable body size differences among populations, between sexes and wing morphs were detected. As a general trend, females were larger than males and macropterous individuals showed increased thorax length over brachypterous which can be explained by the morphological requirements for the development of flight muscles in the thoracic cavity favoring dispersal. Moreover, when comparing wing morphs, a higher phenotypic variability was detected in macropterous females. The frequency of macropterous individuals showed negative correlation with longitude and positive with precipitations, indicating that the macropterous morph is more frequent in the humid eastern part of the studied area. Our results provide valuable about spatial variation of fully winged morph and revealed geographic areas in which the species would experience greater dispersal capacity.

A highly aggregated geographical distribution of forest pest invasions in the USA

Treesearch

Andrew M. Liebhold; Deborah G. McCullough; Laura M. Blackburn; Susan J. Frankel; Betsy Von Holle; Juliann E. Aukema

2013-01-01

Geographical variation in numbers of established non-native species provides clues to the underlying processes driving biological invasions. Specifically, this variation reflects landscape characteristics that drive non-native species arrival, establishment and spread. Here, we investigate spatial variation in damaging non-native forest insect and pathogen species to...

Indicator 1.07. Number and geographic distribution of forest-associated species at risk of losing genetic variation and locally adapted genotypes

Treesearch

C. H. Flather; M. S Knowles; C. H. Sieg

2011-01-01

This indicator provides information on the number and distribution of forest-associated species at risk of losing genetic variation across their geographic range. Comparing a species' current geographic distribution with its historic distribution is the basis for identifying those species whose range has contracted significantly. Human activities are accelerating...

Genetic Variation and Geographic Differentiation Among Populations of the Nonmigratory Agricultural Pest Oedaleus infernalis (Orthoptera: Acridoidea) in China

PubMed Central

Sun, Wei; Dong, Hui; Gao, Yue-Bo; Su, Qian-Fu; Qian, Hai-Tao; Bai, Hong-Yan; Zhang, Zhu-Ting; Cong, Bin

2015-01-01

The nonmigratory grasshopper Oedaleus infernalis Saussure (Orthoptera : Acridoidea) is an agricultural pest to crops and forage grasses over a wide natural geographical distribution in China. The genetic diversity and genetic variation among 10 geographically separated populations of O. infernalis was assessed using polymerase chain reaction-based molecular markers, including the intersimple sequence repeat and mitochondrial cytochrome oxidase sequences. A high level of genetic diversity was detected among these populations from the intersimple sequence repeat (H: 0.2628, I: 0.4129, Hs: 0.2130) and cytochrome oxidase analyses (Hd: 0.653). There was no obvious geographical structure based on an unweighted pair group method analysis and median-joining network. The values of FST, θII, and Gst estimated in this study are low, and the gene flow is high (Nm > 4). Analysis of the molecular variance suggested that most of the genetic variation occurs within populations, whereas only a small variation takes place between populations. No significant correlation was found between the genetic distance and geographical distance. Overall, our results suggest that the geographical distance plays an unimpeded role in the gene flow among O. infernalis populations. PMID:26496789

Isolated populations of a rare alpine plant show high genetic diversity and considerable population differentiation.

PubMed

Aegisdóttir, Hafdís Hanna; Kuss, Patrick; Stöcklin, Jürg

2009-12-01

Gene flow and genetic variability within and among alpine plant populations can be greatly influenced by the steep environmental gradients and heterogeneous topography of alpine landscapes. In this study, the effects are examined of natural isolation of alpine habitats on genetic diversity and geographic structure in populations of C. thyrsoides, a rare and isolated European Alpine monocarpic perennial with limited seed dispersal capacity. Molecular diversity was analysed for 736 individuals from 32 populations in the Swiss Alps and adjacent Jura mountains using five polymorphic microsatellite loci. Pollen flow was estimated using pollen grain-sized fluorescent powder. In addition, individual-based Bayesian approaches were applied to examine population structure. High within-population genetic diversity (H(E) = 0.76) and a relatively low inbreeding coefficient (F(IS) = 0.022) were found. Genetic differentiation among populations measured with a standardized measure was considerable (G'(ST) = 0.53). A significant isolation-by-distance relationship was found (r = 0.62, P < 0.001) and a significant geographic sub-structure, coinciding with proposed postglacial migration patterns. Altitudinal location and size of populations did not influence molecular variation. Direct measures of pollen flow revealed that insect-mediated pollen dispersal was restricted to short distances within a population. The natural isolation of suitable habitats for C. thyrsoides restricts gene flow among the populations as expected for a monocarpic species with very limited seed dispersal capacities. The observed high within-population genetic diversity in this rare monocarpic perennial is best explained by its outcrossing behaviour, long-lived individuals and overlapping generations. Despite the high within-population genetic diversity, the considerable genetic differentiation and the clear western-eastern differentiation in this species merits consideration in future conservation efforts.

Genomic Differentiation during Speciation-with-Gene-Flow: Comparing Geographic and Host-Related Variation in Divergent Life History Adaptation in Rhagoletis pomonella

PubMed Central

Hood, Glen R.; Meyers, Peter J.; Powell, Thomas H. Q.; Lazorchak, Peter; Glover, Mary M.; Tait, Cheyenne; Hahn, Daniel A.; Berlocher, Stewart H.; Smith, James J.; Nosil, Patrik; Feder, Jeffrey L.

2018-01-01

A major goal of evolutionary biology is to understand how variation within populations gets partitioned into differences between reproductively isolated species. Here, we examine the degree to which diapause life history timing, a critical adaptation promoting population divergence, explains geographic and host-related genetic variation in ancestral hawthorn and recently derived apple-infesting races of Rhagoletis pomonella. Our strategy involved combining experiments on two different aspects of diapause (initial diapause intensity and adult eclosion time) with a geographic survey of genomic variation across four sites where apple and hawthorn flies co-occur from north to south in the Midwestern USA. The results demonstrated that the majority of the genome showing significant geographic and host-related variation can be accounted for by initial diapause intensity and eclosion time. Local genomic differences between sympatric apple and hawthorn flies were subsumed within broader geographic clines; allele frequency differences within the races across the Midwest were two to three-fold greater than those between the races in sympatry. As a result, sympatric apple and hawthorn populations displayed more limited genomic clustering compared to geographic populations within the races. The findings suggest that with reduced gene flow and increased selection on diapause equivalent to that seen between geographic sites, the host races may be recognized as different genotypic entities in sympatry, and perhaps species, a hypothesis requiring future genomic analysis of related sibling species to R. pomonella to test. Our findings concerning the way selection and geography interplay could be of broad significance for many cases of earlier stages of divergence-with-gene flow, including (1) where only modest increases in geographic isolation and the strength of selection may greatly impact genetic coupling and (2) the dynamics of how spatial and temporal standing variation is extracted by selection to generate differences between new and discrete units of biodiversity. PMID:29783692

Genomic Differentiation during Speciation-with-Gene-Flow: Comparing Geographic and Host-Related Variation in Divergent Life History Adaptation in Rhagoletis pomonella.

PubMed

Doellman, Meredith M; Ragland, Gregory J; Hood, Glen R; Meyers, Peter J; Egan, Scott P; Powell, Thomas H Q; Lazorchak, Peter; Glover, Mary M; Tait, Cheyenne; Schuler, Hannes; Hahn, Daniel A; Berlocher, Stewart H; Smith, James J; Nosil, Patrik; Feder, Jeffrey L

2018-05-18

A major goal of evolutionary biology is to understand how variation within populations gets partitioned into differences between reproductively isolated species. Here, we examine the degree to which diapause life history timing, a critical adaptation promoting population divergence, explains geographic and host-related genetic variation in ancestral hawthorn and recently derived apple-infesting races of Rhagoletis pomonella . Our strategy involved combining experiments on two different aspects of diapause (initial diapause intensity and adult eclosion time) with a geographic survey of genomic variation across four sites where apple and hawthorn flies co-occur from north to south in the Midwestern USA. The results demonstrated that the majority of the genome showing significant geographic and host-related variation can be accounted for by initial diapause intensity and eclosion time. Local genomic differences between sympatric apple and hawthorn flies were subsumed within broader geographic clines; allele frequency differences within the races across the Midwest were two to three-fold greater than those between the races in sympatry. As a result, sympatric apple and hawthorn populations displayed more limited genomic clustering compared to geographic populations within the races. The findings suggest that with reduced gene flow and increased selection on diapause equivalent to that seen between geographic sites, the host races may be recognized as different genotypic entities in sympatry, and perhaps species, a hypothesis requiring future genomic analysis of related sibling species to R. pomonella to test. Our findings concerning the way selection and geography interplay could be of broad significance for many cases of earlier stages of divergence-with-gene flow, including (1) where only modest increases in geographic isolation and the strength of selection may greatly impact genetic coupling and (2) the dynamics of how spatial and temporal standing variation is extracted by selection to generate differences between new and discrete units of biodiversity.

Variation in Chemotherapy Utilization in Ovarian Cancer: The Relative Contribution of Geography

PubMed Central

Polsky, Daniel; Armstrong, Katrina A; Randall, Thomas C; Ross, Richard N; Even-Shoshan, Orit; Rosenbaum, Paul R; Silber, Jeffrey H

2006-01-01

Objective This study investigates geographic variation in chemotherapy utilization for ovarian cancer in both absolute and relative terms and examines area characteristics associated with this variation. Data Sources Surveillance, Epidemiology, and End Results (SEER) Medicare data from 1990 to 2001 for Medicare patients over 65 with a diagnosis of ovarian cancer between 1990 and 1999. Chemotherapy within a year of diagnosis was identified by Medicare billing codes. The hospital referral region (HRR) represents the geographic unit of analysis. Study Design A logit model predicting the probability of receiving chemotherapy by each of the 39 HRRs. Control variables included medical characteristics (patient age, stage, year of diagnosis, and comorbidities) and socioeconomic characteristics (race, income, and education). The variation among HRRs was tested by the χ2 statistic, and the relative contribution was measured by the ω statistic. HHR market characteristic are then used to explain HRR-level variation. Principal Findings The average chemotherapy rate was 56.6 percent, with a range by HRR from 33 percent to 67 percent. There were large and significant differences in chemotherapy use between HRRs, reflected by a χ2 for HRR of 146 (df=38, p<.001). HRR-level variation in chemotherapy use can be partially explained by higher chemotherapy rates in HRRs with a higher percentage of hospitals with oncology services. However, an ω analysis indicates that, by about 15 to one, the variation between patients in use of chemotherapy reflects variations in patient characteristics rather than unexplained variation among HRRs. Conclusions While absolute levels of chemotherapy variation between geographic areas are large and statistically significant, this analysis suggests that the role of geography in determining who gets chemotherapy is small relative to individual medical characteristics. Nevertheless, while variation by medical characteristics can be medically justified, the same cannot be said for geographic variation. Our finding that density of oncology hospitals predicts chemotherapy use suggests that provider supply is positively correlated with geographic variation. PMID:17116116

Assessment of the magnitude of geographical variations in the duration of non-work-related sickness absence by individual and contextual factors.

PubMed

Torá-Rocamora, Isabel; Martínez, José Miguel; Gimeno, David; Alberti, Constança; Jardí, Josefina; Manzanera, Rafael; Benavides, Fernando G; Delclos, George

2015-01-01

To examine variation in the duration of non-work-related sickness absence (NWRSA) across geographical areas and the degree to which this variation can be explained by individual and/or contextual factors. All first NWRSA episodes ending in 2007 and 2010 were analyzed. Individual (diagnosis, age, sex) and contextual factors (healthcare resources, socioeconomic factors) were analyzed to assess how much of the geographical variation was explained by these factors. Median NWRSA durations in quartiles were mapped by counties in Catalonia. Multilevel Cox proportional hazard regression models with episodes nested within counties were fitted to quantify the magnitude of this variation. The proportional change in variance (PCV), median hazard ratios (MHR) and interquartile hazard ratios (IHR) were calculated. We found a geographical pattern in the duration of NWRSA, with longer duration in northwestern Catalonia. There was a small, but statistically significant, geographical variation in the duration of NWRSA, which mostly decreased after adjustment for individual factors in both women (PCV=34.98%, MHR=1.09, IHR=1.13 in 2007; PCV=34.68%, MHR=1.11, IHR=1.28 in 2010) and men (PCV=39.88%, MHR=1.10, IHR=1.27 in 2007; PCV=45.93%, MHR=1.10, IHR=1.25 in 2010); only in the case of women in 2010 was there a reduction in county-level variance due to contextual covariates (PCV=16.18%, MHR=1.12, IHR=1.32). County-level variation in the duration of NWRSA was small and was explained more by individual than by contextual variables. Knowledge of geographic differences in NWRSA duration is needed to plan specific programs and interventions to minimize these differences. Copyright © 2014 SESPAS. Published by Elsevier Espana. All rights reserved.

Negative Association of Hospital Efficiency Under Increasing Geographic Elevation on Acute Myocardial Infarction In-Patient Mortality.

PubMed

Devaraj, Srikant; Patel, Pankaj C

Although variation in-patient outcomes based on hospitals' geographic location has been studied, altitude of hospitals above sea level may also affect patient outcomes. Possibly, because of negative physical and psychological effects of altitude on hospital employees, hospital efficiency may decline at higher altitudes. Greater focus on hospital efficiency, despite decreasing efficiency at higher altitudes, could increase demands on hospital employees and further deteriorate patient outcomes. Using data envelopment analysis on a sample of 840 hospital-year observations representing 95,504 patients with acute myocardial infarction (AMI) in the United States, and controlling for patient, hospital, and county characteristics and controlling for hospital, state, and year fixed effects, we find support for the negative association between hospital altitude and efficiency; for 1 percentage point increase in efficiency and every 1,000 feet increase in altitude above the sea level, the mortality of patients with AMI increases by 0.66 percentage points. The findings have implications for hospital performance at increasing geographic elevation and introduces to the literature the notion of "health economics of elevation," to suggest that elevation of a hospital may be an important criterion for consideration for policy makers and insurance firms.

Temporal trends and geographical variation in the use of subacromial decompression and rotator cuff repair of the shoulder in England.

PubMed

Judge, A; Murphy, R J; Maxwell, R; Arden, N K; Carr, A J

2014-01-01

We explored the trends over time and the geographical variation in the use of subacromial decompression and rotator cuff repair in 152 local health areas (Primary Care Trusts) across England. The diagnostic and procedure codes of patients undergoing certain elective shoulder operations between 2000/2001 and 2009/2010 were extracted from the Hospital Episode Statistics database. They were grouped as 1) subacromial decompression only, 2) subacromial decompression with rotator cuff repair, and 3) rotator cuff repair only. The number of patients undergoing subacromial decompression alone rose by 746.4% from 2523 in 2000/2001 (5.2/100 000 (95% confidence interval (CI) 5.0 to 5.4) to 21 355 in 2009/2010 (40.2/100 000 (95% CI 39.7 to 40.8)). Operations for rotator cuff repair alone peaked in 2008/2009 (4.7/100 000 (95% CI 4.5 to 4.8)) and declined considerably in 2009/2010 (2.6/100 000 (95% CI 2.5 to 2.7)). Given the lack of evidence for the effectiveness of these operations and the significant increase in the number of procedures being performed in England and elsewhere, there is an urgent need for well-designed clinical trials to determine evidence of clinical effectiveness.

Overcoming the dichotomy between open and isolated populations using genomic data from a large European dataset

PubMed Central

Anagnostou, Paolo; Dominici, Valentina; Battaggia, Cinzia; Pagani, Luca; Vilar, Miguel; Wells, R. Spencer; Pettener, Davide; Sarno, Stefania; Boattini, Alessio; Francalacci, Paolo; Colonna, Vincenza; Vona, Giuseppe; Calò, Carla; Destro Bisol, Giovanni; Tofanelli, Sergio

2017-01-01

Human populations are often dichotomized into “isolated” and “open” categories using cultural and/or geographical barriers to gene flow as differential criteria. Although widespread, the use of these alternative categories could obscure further heterogeneity due to inter-population differences in effective size, growth rate, and timing or amount of gene flow. We compared intra and inter-population variation measures combining novel and literature data relative to 87,818 autosomal SNPs in 14 open populations and 10 geographic and/or linguistic European isolates. Patterns of intra-population diversity were found to vary considerably more among isolates, probably due to differential levels of drift and inbreeding. The relatively large effective size estimated for some population isolates challenges the generalized view that they originate from small founding groups. Principal component scores based on measures of intra-population variation of isolated and open populations were found to be distributed along a continuum, with an area of intersection between the two groups. Patterns of inter-population diversity were even closer, as we were able to detect some differences between population groups only for a few multidimensional scaling dimensions. Therefore, different lines of evidence suggest that dichotomizing human populations into open and isolated groups fails to capture the actual relations among their genomic features. PMID:28145502

Quantitative analysis of the impacts of terrestrial environmental factors on precipitation variation over the Beibu Gulf Economic Zone in Coastal Southwest China.

PubMed

Zhao, Yinjun; Deng, Qiyu; Lin, Qing; Cai, Chunting

2017-03-15

Taking the Guangxi Beibu Gulf Economic Zone as the study area, this paper utilizes the geographical detector model to quantify the feedback effects from the terrestrial environment on precipitation variation from 1985 to 2010 with a comprehensive consideration of natural factors (forest coverage rate, vegetation type, terrain, terrestrial ecosystem types, land use and land cover change) and social factors (population density, farmland rate, GDP and urbanization rate). First, we found that the precipitation trend rate in the Beibu Gulf Economic Zone is between -47 and 96 mm/10a. Second, forest coverage rate change (FCRC), urbanization rate change (URC), GDP change (GDPC) and population density change (PDC) have a larger contribution to precipitation change through land-surface feedback, which makes them the leading factors. Third, the human element is found to primarily account for the precipitation changes in this region, as humans are the active media linking and enhancing these impact factors. Finally, it can be concluded that the interaction of impact factor pairs has a significant effect compared to the corresponding single factor on precipitation changes. The geographical detector model offers an analytical framework to reveal the terrestrial factors affecting the precipitation change, which gives direction for future work on regional climate modeling and analyses.

Genetic Diversity and Geographical Gene Flow Patterns of Spawning Broadcast Coral Lobophyllia corymbosa in The Sulawesi Waters as A Coral Triangle Area

NASA Astrophysics Data System (ADS)

Umar, Widyastuti; Jompa, Jamaluddin; Tassakka, Asmi Citra Malina A. R.

2018-02-01

The existence of hard coral is one of the keys to maintain the suistainability of ecosystem in the waters. Currently, the hard coral keeps declining over time due to various disturbances. In addition, hard coral where fish and other organisms live in will directly affect the ecosystem sustainability if the damage still happens. Molecular approach, such as knowing the genetic variation information of coral population can be an informative study to estimate the condition of waters, so that, conservation efforts can be easily done. In this study, we use Lobophyllia corymbosa as a spawning broadcast coral to be the sample which is collected from Sinjai and Luwuk Banggai. The study areas are selected based on geographical patterns which are in the South and East of Sulawesi waters. Since they have a considerable distance, it is likely for them to produce high genetic variations. Genome DNA uses mitochondrial genome that is extracted from coral tissue. The result shows that the genetic diversity is high. From the two major groups provided, there have been 8 haplotypes for all locations. In addition, the L.corymbosa distribution between Sinjai and Luwuk banggai has a high genetic connectivity with 0.6 fixation index.

Geographical variations of the skull in the red fox Vulpes vulpes on the Japanese Islands: an exception to Bergmann's rule.

PubMed

Oishi, Takuya; Uraguchi, Kohji; Abramov, Alexei V; Masuda, Ryuichi

2010-12-01

In order to clarify the morphological differences between two subspecies of the red fox (Vulpes vulpes) on the Japanese Islands and test the validity of Bergmann's rule, we examined geographical variations in 25 cranial and 24 dental characters in V. v. schrencki from Hokkaido and V. v. japonica from the other main islands of Japan (Honshu, Shikoku, and Kyushu). Many skull measurements, including the male greatest length, condylobasal length, and the length of upper and lower tooth rows, were significantly larger for V. v. japonica than for V. v. schrencki, whereas most tooth measurements, especially the length of molars and premolars, in V. v. schrencki were larger than those in V. v. japonica. Although the two subspecies were morphologically well-differentiated from each other, the results did not support that they have evolved following Bergmann's rule of adaptation to cold climates. Based on consideration of the relatively large differences of their tooth sizes, which are not easily influenced by food abundance, and previous genetic research on the different migration histories of the two subspecies, the morphological differences detected in the present study may have resulted not only from the present ecological differences between the two subspecies, but also from the difference of migration history and evolutionary constraints.

Quantitative analysis of the impacts of terrestrial environmental factors on precipitation variation over the Beibu Gulf Economic Zone in Coastal Southwest China

NASA Astrophysics Data System (ADS)

Zhao, Yinjun; Deng, Qiyu; Lin, Qing; Cai, Chunting

2017-03-01

Taking the Guangxi Beibu Gulf Economic Zone as the study area, this paper utilizes the geographical detector model to quantify the feedback effects from the terrestrial environment on precipitation variation from 1985 to 2010 with a comprehensive consideration of natural factors (forest coverage rate, vegetation type, terrain, terrestrial ecosystem types, land use and land cover change) and social factors (population density, farmland rate, GDP and urbanization rate). First, we found that the precipitation trend rate in the Beibu Gulf Economic Zone is between -47 and 96 mm/10a. Second, forest coverage rate change (FCRC), urbanization rate change (URC), GDP change (GDPC) and population density change (PDC) have a larger contribution to precipitation change through land-surface feedback, which makes them the leading factors. Third, the human element is found to primarily account for the precipitation changes in this region, as humans are the active media linking and enhancing these impact factors. Finally, it can be concluded that the interaction of impact factor pairs has a significant effect compared to the corresponding single factor on precipitation changes. The geographical detector model offers an analytical framework to reveal the terrestrial factors affecting the precipitation change, which gives direction for future work on regional climate modeling and analyses.

Schistosomiasis in Malawi: a systematic review.

PubMed

Makaula, Peter; Sadalaki, John R; Muula, Adamson S; Kayuni, Sekeleghe; Jemu, Samuel; Bloch, Paul

2014-12-10

Schistosomiasis remains an important public health problem that undermines social and economic development in tropical regions of the world, mainly Sub-Saharan Africa. We are not aware of any systematic review of the literature of the epidemiology and transmission of schistosomiasis in Malawi since 1985. Therefore, we reviewed the current state of knowledge of schistosomiasis epidemiology and transmission in this country and identified knowledge gaps and relevant areas for future research and research governance. We conducted computer-aided literature searches of Medline, SCOPUS and Google Scholar using the keywords: "schistosomiasis", "Bilharzia", "Bulinus" and "Biomphalaria" in combination with "Malawi". These searches were supplemented by iterative reviews of reference lists for relevant publications in peer reviewed international scientific journals or other media. The recovered documents were reviewed for their year of publication, location of field or laboratory work, authorship characteristics, ethics review, funding sources as well as their findings regarding parasite and intermediate host species, environmental aspects, geographical distribution, seasonality of transmission, and infection prevalence and intensities. A total of 89 documents satisfied the inclusion criteria and were reviewed. Of these, 76 were published in international scientific journals, 68 were peer reviewed and 54 were original research studies. Most of the documents addressed urinary schistosomiasis and about two thirds of them dealt with the definitive host. Few documents addressed the parasites and the intermediate hosts. While urinary schistosomiasis occurs in most parts of Malawi, intestinal schistosomiasis mainly occurs in the central and southern highlands, Likoma Island and Lower Shire. Studies in selected communities estimated prevalence rates of up to 94.9% for Schistosoma haematobium and up to 67.0% for Schistosoma mansoni with considerable geographical variation. The main intermediate host species are Bulinus globosus and Bulinus nyassanus for urinary schistosomiasis and Biomphalaria pfeifferi for intestinal schistosomiasis. Seasonality of transmission tends to vary according to geographical, environmental, biological and behavioural factors. Transmission of schistosomiasis in Malawi appears to be highly focal, with considerable variation in space and time. Many locations have not been covered by epidemiological investigations and, thus, information on the transmission of schistosomiasis in Malawi remains fragmented. Functional infection risk assessment systems based on systematic investigations and surveillance are required for developing informed prevention and control strategies.

Geographic Information System Software to Remodel Population Data Using Dasymetric Mapping Methods

USGS Publications Warehouse

Sleeter, Rachel; Gould, Michael

2007-01-01

The U.S. Census Bureau provides decadal demographic data collected at the household level and aggregated to larger enumeration units for anonymity purposes. Although this system is appropriate for the dissemination of large amounts of national demographic data, often the boundaries of the enumeration units do not reflect the distribution of the underlying statistical phenomena. Conventional mapping methods such as choropleth mapping, are primarily employed due to their ease of use. However, the analytical drawbacks of choropleth methods are well known ranging from (1) the artificial transition of population at the boundaries of mapping units to (2) the assumption that the phenomena is evenly distributed across the enumeration unit (when in actuality there can be significant variation). Many methods to map population distribution have been practiced in geographic information systems (GIS) and remote sensing fields. Many cartographers prefer dasymetric mapping to map population because of its ability to more accurately distribute data over geographic space. Similar to ?choropleth maps?, a dasymetric map utilizes standardized data (for example, census data). However, rather than using arbitrary enumeration zones to symbolize population distribution, a dasymetric approach introduces ancillary information to redistribute the standardized data into zones relative to land use and land cover (LULC), taking into consideration actual changing densities within the boundaries of the enumeration unit. Thus, new zones are created that correlate to the function of the map, capturing spatial variations in population density. The transfer of data from census enumeration units to ancillary-driven homogenous zones is performed by a process called areal interpolation.

Genes mirror geography in Daphnia magna.

PubMed

Fields, Peter D; Reisser, Céline; Dukić, Marinela; Haag, Christoph R; Ebert, Dieter

2015-09-01

Identifying the presence and magnitude of population genetic structure remains a major consideration in evolutionary biology as doing so allows one to understand the demographic history of a species as well as make predictions of how the evolutionary process will proceed. Next-generation sequencing methods allow us to reconsider previous ideas and conclusions concerning the distribution of genetic variation, and what this distribution implies about a given species evolutionary history. A previous phylogeographic study of the crustacean Daphnia magna suggested that, despite strong genetic differentiation among populations at a local scale, the species shows only moderate genetic structure across its European range, with a spatially patchy occurrence of individual lineages. We apply RAD sequencing to a sample of D. magna collected across a wide swath of the species' Eurasian range and analyse the data using principle component analysis (PCA) of genetic variation and Procrustes analytical approaches, to quantify spatial genetic structure. We find remarkable consistency between the first two PCA axes and the geographic coordinates of individual sampling points, suggesting that, on a continent-wide scale, genetic differentiation is driven to a large extent by geographic distance. The observed pattern is consistent with unimpeded (i.e. no barriers, landscape or otherwise) migration at large spatial scales, despite the fragmented and patchy nature of favourable habitats at local scales. With high-resolution genetic data similar patterns may be uncovered for other species with wide geographic distributions, allowing an increased understanding of how genetic drift and selection have shaped their evolutionary history. © 2015 John Wiley & Sons Ltd.

History Shaped the Geographic Distribution of Genomic Admixture on the Island of Puerto Rico

PubMed Central

Via, Marc; Gignoux, Christopher R.; Roth, Lindsey A.; Fejerman, Laura; Galanter, Joshua; Choudhry, Shweta; Toro-Labrador, Gladys; Viera-Vera, Jorge; Oleksyk, Taras K.; Beckman, Kenneth; Ziv, Elad; Risch, Neil

2011-01-01

Contemporary genetic variation among Latin Americans human groups reflects population migrations shaped by complex historical, social and economic factors. Consequently, admixture patterns may vary by geographic regions ranging from countries to neighborhoods. We examined the geographic variation of admixture across the island of Puerto Rico and the degree to which it could be explained by historic and social events. We analyzed a census-based sample of 642 Puerto Rican individuals that were genotyped for 93 ancestry informative markers (AIMs) to estimate African, European and Native American ancestry. Socioeconomic status (SES) data and geographic location were obtained for each individual. There was significant geographic variation of ancestry across the island. In particular, African ancestry demonstrated a decreasing East to West gradient that was partially explained by historical factors linked to the colonial sugar plantation system. SES also demonstrated a parallel decreasing cline from East to West. However, at a local level, SES and African ancestry were negatively correlated. European ancestry was strongly negatively correlated with African ancestry and therefore showed patterns complementary to African ancestry. By contrast, Native American ancestry showed little variation across the island and across individuals and appears to have played little social role historically. The observed geographic distributions of SES and genetic variation relate to historical social events and mating patterns, and have substantial implications for the design of studies in the recently admixed Puerto Rican population. More generally, our results demonstrate the importance of incorporating social and geographic data with genetics when studying contemporary admixed populations. PMID:21304981

Geographic variation in marine turtle fibropapillomatosis

USGS Publications Warehouse

Greenblatt, R.J.; Work, Thierry M.; Dutton, P.; Sutton, C.A.; Spraker, T.R.; Casey, R.N.; Diez, C.E.; Parker, Dana C.; St. Ledger, J.; Balazs, G.H.; Casey, J.W.

2005-01-01

We document three examples of fibropapillomatosis by histology, quantitative polymerase chain reaction (qPCR), and sequence analysis from three different geographic areas. Tumors compatible in morphology with fibropapillomatosis were seen in green turtles from Puerto Rico and San Diego (California) and in a hybrid loggerhead/ hawksbill turtle from Florida Bay (Florida). Tumors were confirmed as fibropapillomas on histology, although severity of disease varied between cases. Polymerase chain reaction (PCR) analyses revealed infection with the fibropapilloma-associated turtle herpesvirus (FPTHV) in all cases, albeit at highly variable copy numbers per cell. Alignment of a portion of the polymerase gene from each fibropapilloma-associated turtle herpesvirus isolate demonstrated geographic variation in sequence. These cases illustrate geographic variation in both the pathology and the virology of fibropapillomatosis.

Geographic variation in marine turtle fibropapillomatosis.

PubMed

Greenblatt, Rebecca J; Work, Thierry M; Dutton, Peter; Sutton, Claudia A; Spraker, Terry R; Casey, Rufina N; Diez, Carlos E; Parker, Denise; St Leger, Judy; Balazs, George H; Casey, James W

2005-09-01

We document three examples of fibropapillomatosis by histology, quantitative polymerase chain reaction (qPCR), and sequence analysis from three different geographic areas. Tumors compatible in morphology with fibropapillomatosis were seen in green turtles from Puerto Rico and San Diego (California) and in a hybrid loggerhead/ hawksbill turtle from Florida Bay (Florida). Tumors were confirmed as fibropapillomas on histology, although severity of disease varied between cases. Polymerase chain reaction (PCR) analyses revealed infection with the fibropapilloma-associated turtle herpesvirus (FPTHV) in all cases, albeit at highly variable copy numbers per cell. Alignment of a portion of the polymerase gene from each fibropapilloma-associated turtle herpesvirus isolate demonstrated geographic variation in sequence. These cases illustrate geographic variation in both the pathology and the virology of fibropapillomatosis.

Genetic evidence supports song learning in the three-wattled bellbird Procnias tricarunculata (Cotingidae).

PubMed

Saranathan, Vinodkumar; Hamilton, Deborah; Powell, George V N; Kroodsma, Donald E; Prum, Richard O

2007-09-01

Vocal learning is thought to have evolved in three clades of birds (parrots, hummingbirds, and oscine passerines), and three clades of mammals (whales, bats, and primates). Behavioural data indicate that, unlike other suboscine passerines, the three-wattled bellbird Procnias tricarunculata (Cotingidae) is capable of vocal learning. Procnias tricarunculata shows conspicuous vocal ontogeny, striking geographical variation in song, and rapid temporal change in song within a population. Deprivation studies of vocal development in P. tricarunculata are impractical. Here, we report evidence from mitochondrial DNA sequences and nuclear microsatellite loci that genetic variation within and among the four allopatric breeding populations of P. tricarunculata is not congruent with variation in vocal behaviour. Sequences of the mitochondrial DNA control region document extensive haplotype sharing among localities and song types, and no phylogenetic resolution of geographical populations or behavioural groups. The vocally differentiated, allopatric breeding populations of P. tricarunculata are only weakly genetically differentiated populations, and are not distinct taxa. Mitochondrial DNA and microsatellite variation show small (2.9% and 13.5%, respectively) but significant correlation with geographical distance, but no significant residual variation by song type. Estimates of the strength of selection that would be needed to maintain the observed geographical pattern in vocal differentiation if songs were genetically based are unreasonably high, further discrediting the hypothesis of a genetic origin of vocal variation. These data support a fourth, phylogenetically independent origin of avian vocal learning in Procnias. Geographical variations in P. tricarunculata vocal behaviour are likely culturally evolved dialects.

Geographic variations in orthopedic trauma billing and reimbursements for hip and pelvis fractures in the Medicare population.

PubMed

Dodd, Ashley C; Lakomkin, Nikita; Bulka, Catherine; Thakore, Rachel; Collinge, Cory A; Sethi, Manish K

2016-12-01

We investigated geographic variations in Medicare spending for DRG 536 (hip and pelvis fracture). We identified 22,728 patients. The median number of charges, discharges, and payments were recorded. Hospitals were aggregated into core based statistical (CBS) areas and the coefficient of variation (CV) was calculated for each area. On average, hospitals charged 3.75 times more than they were reimbursed. Medicare charges and reimbursements demonstrated variability within each area. Geographic variation in Medicare spending for hip fractures is currently unexplained. It is imperative for orthopedists to understand drivers behind such high variability in hospital charges for management of hip and pelvis fractures.

Geographic variation in mimetic precision among different species of coral snake mimics.

PubMed

Akcali, C K; Pfennig, D W

2017-07-01

Batesian mimicry is widespread, but whether and why different species of mimics vary geographically in resemblance to their model is unclear. We characterized geographic variation in mimetic precision among four Batesian mimics of coral snakes. Each mimic occurs where its model is abundant (i.e. in 'deep sympatry'), rare (i.e. at the sympatry/allopatry boundary or 'edge sympatry') and absent (i.e. in allopatry). Geographic variation in mimetic precision was qualitatively different among these mimics. In one mimic, the most precise individuals occurred in edge sympatry; in another, they occurred in deep sympatry; in the third, they occurred in allopatry; and in the fourth, precise mimics were not concentrated anywhere throughout their range. Mimicry was less precise in allopatry than in sympatry in only two mimics. We present several nonmutually exclusive hypotheses for these patterns. Generally, examining geographic variation in mimetic precision - within and among different mimics - offers novel insights into the causes and consequences of mimicry. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

The latitudinal diversity gradient in South American mammals revisited using a regional analysis approach: The importance of climate at extra-tropical latitudes and history towards the tropics

PubMed Central

Ruggiero, Adriana

2017-01-01

The latitudinal diversity gradient has been considered a consequence of a shift in the impact of abiotic and biotic factors that limit species distributions from the poles to the equator, thus influencing species richness variation. It has also been considered the outcome of evolutionary processes that vary over geographical space. We used six South American mammal groups to test the association of environmental and evolutionary factors and the ecological structuring of mammal assemblages with spatial variation in taxonomic richness (TR), at a spatial resolution of 110 km x 110 km, at tropical and extra-tropical latitudes. Based on attributes that represent what mammal species do in ecosystems, we estimated ecological diversity (ED) as a mean pairwise ecological distance between all co-occurring taxa. The mean pairwise phylogenetic distance between all co-occurring taxa (AvPD) was used as an estimation of phylogenetic diversity. Geographically Weighted Regression analyses performed separately for each mammal group identified tropical and extra-tropical high R2 areas where environmental and evolutionary factors strongly accounted for richness variation. Temperature was the most important predictor of TR in high R2 areas outside the tropics, as was AvPD within the tropics. The proportion of TR variation accounted for by environment (either independently or combined with AvPD) was higher in tropical areas of high richness and low ecological diversity than in tropical areas of high richness and high ecological diversity. In conclusion, we confirmed a shift in the impact of environmental factors, mainly temperature, that best account for mammal richness variation in extra-tropical regions, whereas phylogenetic diversity best accounts for richness variation within the tropics. Environment in combination with evolutionary history explained the coexistence of a high number of ecologically similar species within the tropics. Consideration of the influence of contemporary environmental variables and evolutionary history is crucial to understanding of the latitudinal diversity gradient. PMID:28873434

Parallel Evolution of Copy-Number Variation across Continents in Drosophila melanogaster

PubMed Central

Schrider, Daniel R.; Hahn, Matthew W.; Begun, David J.

2016-01-01

Genetic differentiation across populations that is maintained in the presence of gene flow is a hallmark of spatially varying selection. In Drosophila melanogaster, the latitudinal clines across the eastern coasts of Australia and North America appear to be examples of this type of selection, with recent studies showing that a substantial portion of the D. melanogaster genome exhibits allele frequency differentiation with respect to latitude on both continents. As of yet there has been no genome-wide examination of differentiated copy-number variants (CNVs) in these geographic regions, despite their potential importance for phenotypic variation in Drosophila and other taxa. Here, we present an analysis of geographic variation in CNVs in D. melanogaster. We also present the first genomic analysis of geographic variation for copy-number variation in the sister species, D. simulans, in order to investigate patterns of parallel evolution in these close relatives. In D. melanogaster we find hundreds of CNVs, many of which show parallel patterns of geographic variation on both continents, lending support to the idea that they are influenced by spatially varying selection. These findings support the idea that polymorphic CNVs contribute to local adaptation in D. melanogaster. In contrast, we find very few CNVs in D. simulans that are geographically differentiated in parallel on both continents, consistent with earlier work suggesting that clinal patterns are weaker in this species. PMID:26809315

Spatial and temporal variability of microgeographic genetic structure in white-tailed deer

USGS Publications Warehouse

Scribner, Kim T.; Smith, Michael H.; Chesser, Ronald K.

1997-01-01

Techniques are described that define contiguous genetic subpopulations of white-tailed deer (Odocoileus virginianus) based on the spatial dispersion of 4,749 individuals that possessed discrete character values (alleles or genotypes) during each of 6 years (1974-1979). White-tailed deer were not uniformly distributed in space, but exhibited considerable spatial genetic structuring. Significant non-random clusters of individuals were documented during each year based on specific alleles and genotypes at the Sdh locus. Considerable temporal variation was observed in the position and genetic composition of specific clusters, which reflected changes in allele frequency in small geographic areas. The position of clusters did not consistently correspond with traditional management boundaries based on major discontinuities in habitat (swamp versus upland) and hunt compartments that were defined by roads and streams. Spatio-temporal stability of observed genetic contiguous clusters was interpreted relative to method and intensity of harvest, movements, and breeding ecology.

Geographically Modified PageRank Algorithms: Identifying the Spatial Concentration of Human Movement in a Geospatial Network.

PubMed

Chin, Wei-Chien-Benny; Wen, Tzai-Hung

2015-01-01

A network approach, which simplifies geographic settings as a form of nodes and links, emphasizes the connectivity and relationships of spatial features. Topological networks of spatial features are used to explore geographical connectivity and structures. The PageRank algorithm, a network metric, is often used to help identify important locations where people or automobiles concentrate in the geographical literature. However, geographic considerations, including proximity and location attractiveness, are ignored in most network metrics. The objective of the present study is to propose two geographically modified PageRank algorithms-Distance-Decay PageRank (DDPR) and Geographical PageRank (GPR)-that incorporate geographic considerations into PageRank algorithms to identify the spatial concentration of human movement in a geospatial network. Our findings indicate that in both intercity and within-city settings the proposed algorithms more effectively capture the spatial locations where people reside than traditional commonly-used network metrics. In comparing location attractiveness and distance decay, we conclude that the concentration of human movement is largely determined by the distance decay. This implies that geographic proximity remains a key factor in human mobility.

Pollinator community structure and sources of spatial variation in plant--pollinator interactions in Clarkia xantiana ssp. xantiana.

PubMed

Moeller, David A

2005-01-01

The structure of diverse floral visitor assemblages and the nature of spatial variation in plant-pollinator interactions have important consequences for floral evolution and reproductive interactions among pollinator-sharing plant species. In this study, I use surveys of floral visitor communities across the geographic range of Clarkia xantiana ssp. xantiana (hereafter C. x. xantiana) (Onagraceae) to examine the structure of visitor communities, the specificity of the pollination system, and the role of variation in the abiotic vs. biotic environment in contributing to spatial variation in pollinator abundance and community composition. Although the assemblage of bee visitors to C. x. xantiana is very diverse (49 species), few were regular visitors and likely to act as pollinators. Seventy-four percent of visitor species accounted for only 11% of total visitor abundance and 69% were collected in three or fewer plant populations (of ten). Of the few reliable visitors, Clarkia pollen specialist bees were the most frequent visitors, carried more Clarkia pollen compared to generalist foragers, and were less likely to harbor foreign pollen. Overall, the core group of pollinators was obscured by high numbers of incidental visitors that are unlikely to contribute to pollination. In a geographic context, the composition of specialist pollinator assemblages varied considerably along the abiotic gradient spanning the subspecies' range. However, the overall abundance of specialist pollinators in plant populations was not influenced by the broad-scale abiotic gradient but strongly affected by local plant community associations. C. x. xantiana populations sympatric with pollinator-sharing congeners were visited twice as often by specialists compared to populations occurring alone. These positive indirect interactions among plant species may promote population persistence and species coexistence by enhancing individual reproductive success.

Patterns of DNA barcode variation in Canadian marine molluscs.

PubMed

Layton, Kara K S; Martel, André L; Hebert, Paul D N

2014-01-01

Molluscs are the most diverse marine phylum and this high diversity has resulted in considerable taxonomic problems. Because the number of species in Canadian oceans remains uncertain, there is a need to incorporate molecular methods into species identifications. A 648 base pair segment of the cytochrome c oxidase subunit I gene has proven useful for the identification and discovery of species in many animal lineages. While the utility of DNA barcoding in molluscs has been demonstrated in other studies, this is the first effort to construct a DNA barcode registry for marine molluscs across such a large geographic area. This study examines patterns of DNA barcode variation in 227 species of Canadian marine molluscs. Intraspecific sequence divergences ranged from 0-26.4% and a barcode gap existed for most taxa. Eleven cases of relatively deep (>2%) intraspecific divergence were detected, suggesting the possible presence of overlooked species. Structural variation was detected in COI with indels found in 37 species, mostly bivalves. Some indels were present in divergent lineages, primarily in the region of the first external loop, suggesting certain areas are hotspots for change. Lastly, mean GC content varied substantially among orders (24.5%-46.5%), and showed a significant positive correlation with nearest neighbour distances. DNA barcoding is an effective tool for the identification of Canadian marine molluscs and for revealing possible cases of overlooked species. Some species with deep intraspecific divergence showed a biogeographic partition between lineages on the Atlantic, Arctic and Pacific coasts, suggesting the role of Pleistocene glaciations in the subdivision of their populations. Indels were prevalent in the barcode region of the COI gene in bivalves and gastropods. This study highlights the efficacy of DNA barcoding for providing insights into sequence variation across a broad taxonomic group on a large geographic scale.

Geographical variations in seasonal mortality across the United States: A bioclimatological approach

NASA Astrophysics Data System (ADS)

Kalkstein, Adam

2008-10-01

Human mortality exhibits a strong seasonal pattern with deaths in winter far exceeding those in the summer. Surprisingly, this seasonal trend is evident in all major cities across the United States, seemingly independent of climate. While the pattern itself is clear, its magnitude varies considerably across space, and it is not known if there is regional homogeneity among cities. Additionally, the causal mechanisms relating to pattern variability are not clearly understood. The goal of this study is to conduct a comprehensive geographic analysis of seasonal mortality across the United States, to uncover systematic regional differences in such mortality, and to determine what role weather plays in impacting seasonal mortality rates. Unique seasonal mortality curves were created for 28 Metropolitan Statistical Areas across the United States, and the amplitude and timing of mortality peaks were determined. In addition, seasonality was calculated for different demographic groups and causes of death. Meteorological factors were also evaluated as possible causal mechanisms. The findings here indicate that the seasonality of mortality exhibits strong spatial variation with the largest seasonal mortality amplitudes found in the southwestern United States and the smallest in the North, along with South Florida. In addition, there have been changes in the timing of seasonal mortality; the date of maximum mortality is occurring increasingly early in the year. Demographics also play an important role with women, Whites, and the elderly exhibiting the strongest seasonality in mortality. There is a strong connection between respiratory disease and other causes of death, implying a cause-effect relationship. Meteorology also plays an important role in seasonal mortality; variations in the frequency of certain air masses were associated with changes in the timing and amplitude of seasonal mortality. Finally, there were strong intra-regional similarities that exist among the examined cities, implying that environmental factors are more important than social factors in determining seasonal mortality response. This work begins to fill a large gap within the scientific literature concerning the causes, geographic variation, and meteorological influences on seasonal mortality. Additionally, these results will increase the forecasting capabilities of determining when and where winter mortality will reach unusually high levels.

Distinct Phylogeographic Structures of Wild Radish (Raphanus sativus L. var. raphanistroides Makino) in Japan

PubMed Central

Han, Qingxiang; Higashi, Hiroyuki; Mitsui, Yuki; Setoguchi, Hiroaki

2015-01-01

Coastal plants with simple linear distribution ranges along coastlines provide a suitable system for improving our understanding of patterns of intra-specific distributional history and genetic variation. Due to the combination of high seed longevity and high dispersibility of seeds via seawater, we hypothesized that wild radish would poorly represent phylogeographic structure at the local scale. On the other hand, we also hypothesized that wild radish populations might be geographically differentiated, as has been exhibited by their considerable phenotypic variations along the islands of Japan. We conducted nuclear DNA microsatellite loci and chloroplast DNA haplotype analyses for 486 samples and 144 samples, respectively, from 18 populations to investigate the phylogeographic structure of wild radish in Japan. Cluster analysis supported the existence of differential genetic structures between the Ryukyu Islands and mainland Japan populations. A significant strong pattern of isolation by distance and significant evidence of a recent bottleneck were detected. The chloroplast marker analysis resulted in the generation of eight haplotypes, of which two haplotypes (A and B) were broadly distributed in most wild radish populations. High levels of variation in microsatellite loci were identified, whereas cpDNA displayed low levels of genetic diversity within populations. Our results indicate that the Kuroshio Current would have contributed to the sculpting of the phylogeographic structure by shaping genetic gaps between isolated populations. In addition, the Tokara Strait would have created a geographic barrier between the Ryukyu Islands and mainland Japan. Finally, extant habitat disturbances (coastal erosion), migration patterns (linear expansion), and geographic characteristics (small islands and sea currents) have influenced the expansion and historical population dynamics of wild radish. Our study is the first to record the robust phylogeographic structure in wild radish between the Ryukyu Islands and mainland Japan, and might provide new insight into the genetic differentiation of coastal plants across islands. PMID:26247202

Global epidemiological trends and variations in the burden of gallbladder cancer.

PubMed

Are, Chandrakanth; Ahmad, Humera; Ravipati, Advaitaa; Croo, Darren; Clarey, Dillon; Smith, Lynette; Price, Ray R; Butte, Jean M; Gupta, Sameer; Chaturvedi, Arun; Chowdhury, Sanjib

2017-04-01

The aim of this study is to describe the trends and variations in the global burden of gallbladder cancer (GBC) with an emphasis on geographic variations and female gender. Data (2012-2030) relating to GBC was extracted from GLOBOCAN 2012 database and analyzed. The results of our study document a rising global burden of GBC with geographic and gender variations. The highest burden was noted in the WPRO region (based on WHO regions), Asia (based on continents) and India, Chile, and China (based on countries). The less developed regions of the world account for the majority of the global burden of GBC. The geographic variations are also present within individual countries such as in India and Chile. Females are afflicted at a much higher rate with GBC and this predilection is exaggerated in countries with higher incidence such as India and Chile. In females, people of certain ethnic groups and lower socio-economic standing are at a higher risk. Our study demonstrates a rising global burden of GBC with some specific data on geographic and gender-based variations which can be used to develop strategies at the global as well as the high-risk individual country level. © 2017 Wiley Periodicals, Inc.

Geographical variation in cancer survival in England, 1991–2006: an analysis by Cancer Network

PubMed Central

Quaresma, Manuela; Coleman, Michel P; Gordon, Emma; Forman, David; Rachet, Bernard

2011-01-01

Background Reducing geographical inequalities in cancer survival in England was a key aim of the Calman–Hine Report (1995) and the NHS Cancer Plan (2000). This study assesses whether geographical inequalities changed following these policy developments by analysing the trend in 1-year relative survival in the 28 cancer networks of England. Methods Population-based age-standardised relative survival at 1 year is estimated for 1.4 million patients diagnosed with cancer of the oesophagus, stomach, colon, lung, breast (women) or cervix in England during 1991–2006 and followed up to 2007. Regional and deprivation-specific life tables are built to adjust survival estimates for differences in background mortality. Analysis is divided into three calendar periods: 1991–5, 1996–2000 and 2001–6. Funnel plots are used to assess geographical variation in survival over time. Results One-year relative survival improved for all cancers except cervical cancer. There was a wide geographical variation in survival with generally lower estimates in northern England. This north–south divide became less marked over time, although the overall number of cancer networks that were lower outliers compared with the England value remained stable. Breast cancer was the only cancer for which there was a marked reduction in geographical inequality in survival over time. Conclusion Policy changes over the past two decades coincided with improved relative survival, without an increase in geographical variation. The north–south divide in relative survival became less pronounced over time but geographical inequalities persist. The reduction in geographical inequality in breast cancer survival may be followed by a similar trend for other cancers, provided government recommendations are implemented similarly. PMID:21321064

The Genetic Structure and History of Africans and African Americans

PubMed Central

Tishkoff, Sarah A.; Reed, Floyd A.; Friedlaender, Françoise R.; Ehret, Christopher; Ranciaro, Alessia; Froment, Alain; Hirbo, Jibril B.; Awomoyi, Agnes A.; Bodo, Jean-Marie; Doumbo, Ogobara; Ibrahim, Muntaser; Juma, Abdalla T.; Kotze, Maritha J.; Lema, Godfrey; Moore, Jason H.; Mortensen, Holly; Nyambo, Thomas B.; Omar, Sabah A.; Powell, Kweli; Pretorius, Gideon S.; Smith, Michael W.; Thera, Mahamadou A.; Wambebe, Charles; Weber, James L.; Williams, Scott M.

2010-01-01

Africa is the source of all modern humans, but characterization of genetic variation and of relationships among populations across the continent has been enigmatic. We studied 121 African populations, four African American populations, and 60 non-African populations for patterns of variation at 1327 nuclear microsatellite and insertion/deletion markers. We identified 14 ancestral population clusters in Africa that correlate with self-described ethnicity and shared cultural and/or linguistic properties. We observed high levels of mixed ancestry in most populations, reflecting historical migration events across the continent. Our data also provide evidence for shared ancestry among geographically diverse hunter-gatherer populations (Khoesan speakers and Pygmies). The ancestry of African Americans is predominantly from Niger-Kordofanian (~71%), European (~13%), and other African (~8%) populations, although admixture levels varied considerably among individuals. This study helps tease apart the complex evolutionary history of Africans and African Americans, aiding both anthropological and genetic epidemiologic studies. PMID:19407144

Low Variation in the Polymorphic Clock Gene Poly-Q Region Despite Population Genetic Structure across Barn Swallow (Hirundo rustica) Populations

PubMed Central

Dor, Roi; Lovette, Irby J.; Safran, Rebecca J.; Billerman, Shawn M.; Huber, Gernot H.; Vortman, Yoni; Lotem, Arnon; McGowan, Andrew; Evans, Matthew R.; Cooper, Caren B.; Winkler, David W.

2011-01-01

Recent studies of several species have reported a latitudinal cline in the circadian clock gene, Clock, which influences rhythms in both physiology and behavior. Latitudinal variation in this gene may hence reflect local adaptation to seasonal variation. In some bird populations, there is also an among-individual association between Clock poly-Q genotype and clutch initiation date and incubation period. We examined Clock poly-Q allele variation in the Barn Swallow (Hirundo rustica), a species with a cosmopolitan geographic distribution and considerable variation in life-history traits that may be influenced by the circadian clock. We genotyped Barn Swallows from five populations (from three subspecies) and compared variation at the Clock locus to that at microsatellite loci and mitochondrial DNA (mtDNA). We found very low variation in the Clock poly-Q region, as >96% of individuals were homozygous, and the two other alleles at this locus were globally rare. Genetic differentiation based on the Clock poly-Q locus was not correlated with genetic differentiation based on either microsatellite loci or mtDNA sequences. Our results show that high diversity in Clock poly-Q is not general across avian species. The low Clock variation in the background of heterogeneity in microsatellite and mtDNA loci in Barn Swallows may be an outcome of stabilizing selection on the Clock locus. PMID:22216124

Health, policy and geography: insights from a multi-level modelling approach.

PubMed

Castelli, Adriana; Jacobs, Rowena; Goddard, Maria; Smith, Peter C

2013-09-01

Improving the health and wellbeing of citizens ranks highly on the agenda of most governments. Policy action to enhance health and wellbeing can be targeted at a range of geographical levels and in England the focus has tended to shift away from the national level to smaller areas, such as communities and neighbourhoods. Our focus is to identify the potential for targeting policy interventions at the most appropriate geographical levels in order to enhance health and wellbeing. The rationale is that where variations in health and wellbeing indicators are larger, there may be greater potential for policy intervention targeted at that geographical level to have an impact on the outcomes of interest, compared with a strategy of targeting policy at those levels where relative variations are smaller. We use a multi-level regression approach to identify the degree of variation that exists in a set of health indicators at each level, taking account of the geographical hierarchical organisation of public sector organisations. We find that for each indicator, the proportion of total residual variance is greatest at smaller geographical areas. We also explore the variations in health indicators within a hierarchical level, but across the geographical areas for which public sector organisations are responsible. We show that it is feasible to identify a sub-set of organisations for which unexplained variation in health indicators is significantly greater relative to their counterparts. We demonstrate that adopting a geographical perspective to analyse the variation in indicators of health at different levels offers a potentially powerful analytical tool to signal where public sector organisations, faced increasingly with many competing demands, should target their policy efforts. This is relevant not only to the English context but also to other countries where responsibilities for health and wellbeing are being devolved to localities and communities. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Geographical Variation in Diabetes Prevalence and Detection in China: Multilevel Spatial Analysis of 98,058 Adults

PubMed Central

Zhou, Maigeng; Astell-Burt, Thomas; Bi, Yufang; Feng, Xiaoqi; Jiang, Yong; Li, Yichong; Page, Andrew; Wang, Limin; Xu, Yu

2015-01-01

OBJECTIVE To investigate the geographic variation in diabetes prevalence and detection in China. RESEARCH DESIGN AND METHODS Self-report and biomedical data were collected from 98,058 adults aged ≥18 years (90.5% response) from 162 areas spanning mainland China. Diabetes status was assessed using American Diabetes Association criteria. Among those with diabetes, detection was defined by prior diagnosis. Choropleth maps were used to visually assess geographical variation in each outcome at the provincial level. The odds of each outcome were assessed using multilevel logistic regression, with adjustment for person- and area-level characteristics. RESULTS Geographic visualization at the provincial level indicated widespread variation in diabetes prevalence and detection across China. Regional prevalence adjusted for age, sex, and urban/rural socioeconomic circumstances (SECs) ranged from 8.3% (95% CI 7.2%, 9.7%) in the northeast to 12.7% (11.1%, 14.6%) in the north. A clear negative gradient in diabetes prevalence was observed from 13.1% (12.0%, 14.4%) in the urban high-SEC to 8.7% (7.8%, 9.6%) in rural low-SEC counties/districts. Adjusting for health literacy and other person-level characteristics only partially attenuated these geographic variations. Only one-third of participants living with diabetes had been previously diagnosed, but this also varied substantively by geography. Regional detection adjusted for age, sex, and urban/rural SEC, for example, spanned from 40.4% (34.9%, 46.3%) in the north to 15.6% (11.7%, 20.5%) in the southwest. Compared with detection of 40.8% (37.3%, 44.4%) in urban high-SEC counties, detection was poorest among rural low-SEC counties at just 20.5% (17.7%, 23.7%). Person-level characteristics did not fully account for these geographic variations in diabetes detection. CONCLUSIONS Strategies for addressing diabetes risk and improving detection require geographical targeting. PMID:25352654

AFLP analysis of Cynodon dactylon (L.) Pers. var. dactylon genetic variation.

PubMed

Wu, Y Q; Taliaferro, C M; Bai, G H; Anderson, M P

2004-08-01

Cynodon dactylon (L.) Pers. var. dactylon (common bermudagrass) is geographically widely distributed between about lat 45 degrees N and lat 45 degrees S, penetrating to about lat 53 degrees N in Europe. The extensive variation of morphological and adaptive characteristics of the taxon is substantially documented, but information is lacking on DNA molecular variation in geographically disparate forms. Accordingly, this study was conducted to assess molecular genetic variation and genetic relatedness among 28 C. dactylon var. dactylon accessions originating from 11 countries on 4 continents (Africa, Asia, Australia, and Europe). A fluorescence-labeled amplified fragment length polymorphism (AFLP) DNA profiling method was used to detect the genetic diversity and relatedness. On the basis of 443 polymorphic AFLP fragments from 8 primer combinations, the accessions were grouped into clusters and subclusters associating with their geographic origins. Genetic similarity coefficients (SC) for the 28 accessions ranged from 0.53 to 0.98. Accessions originating from Africa, Australia, Asia, and Europe formed major groupings as indicated by cluster and principal coordinate analysis. Accessions from Australia and Asia, though separately clustered, were relatively closely related and most distantly related to accessions of European origin. African accessions formed two distant clusters and had the greatest variation in genetic relatedness relative to accessions from other geographic regions. Sampling the full extent of genetic variation in C. dactylon var. dactylon would require extensive germplasm collection in the major geographic regions of its distributional range.

The role of standing variation in geographic convergent adaptation

PubMed Central

Ralph, Peter L.; Coop, Graham

2016-01-01

The extent to which populations experiencing shared selective pressures adapt through a shared genetic response is relevant to many questions in evolutionary biology. In a number of well studied traits and species, it appears that convergent evolution within species is common. In this paper, we explore how standing, genetic variation contributes to convergent genetic responses in a geographically spread population, extending our previous work on the topic. Geographically limited dispersal slows the spread of each selected allele, hence allowing other alleles – newly arisen mutants or present as standing variation – to spread before any one comes to dominate the population. When such alleles meet, their progress is substantially slowed – if the alleles are selectively equivalent, they mix slowly, dividing the species range into a random tessellation, which can be well understood by analogy to a Poisson process model of crystallization. In this framework, we derive the geographic scale over which a typical allele is expected to dominate, the time it takes the species to adapt as a whole, and the proportion of adaptive alleles that arise from standing variation. Finally, we explore how negative pleiotropic effects of alleles before an environment change can bias the subset of alleles that contribute to the species’ adaptive response. We apply the results to the many geographically localized G6PD deficiency alleles thought to confer resistance to malaria, where the large mutational target size makes it a likely candidate for adaptation from standing variation, despite the selective cost of G6PD deficiency alleles in the absence of malaria. We find the numbers and geographic spread of these alleles matches our predictions reasonably well, consistent with the view that they arose from a combination of standing variation and new mutations since the advent of malaria. Our results suggest that much of adaptation may be geographically local even when selection pressures are homogeneous. Therefore, we argue that caution must be exercised when arguing that strongly geographically restricted alleles are necessarily the outcome of local adaptation. We close by discussing the implications of these results for ideas of species coherence and the nature of divergence between species. PMID:26656217

Secondary stroke prevention services in Canada: a cross-sectional survey and geospatial analysis of resources, capacity and geographic access

PubMed Central

Jewett, Lauren; Harroud, Adil; Hill, Michael D.; Côté, Robert; Wein, Theodore; Smith, Eric E.; Gubitz, Gord; Demchuk, Andrew M.; Sahlas, Demetrios J.; Gladstone, David J.; Lindsay, M. Patrice

2018-01-01

Background: Rapid assessment and management of transient ischemic attacks and nondisabling strokes by specialized stroke prevention services reduces the risk of recurrent stroke and improves outcomes. In Canada, with its vast geography and with 16.8% of the population living in rural areas, access to these services is challenging, and considerable variation in access to care exists. The purpose of this multiphase study was to identify sites across Canada providing stroke prevention services, evaluate resource capacity and determine geographic access for Canadians. Methods: We developed a Stroke Prevention Services Resource Inventory that contained 22 questions on the organization and delivery of stroke prevention services and quality monitoring. The inventory ran from November 2015 to January 2016 and was administered online. We conducted a geospatial analysis to estimate access by drive times. Considerations were made for hours of operation and access within and across provincial borders. Results: A total of 123 stroke prevention sites were identified, of which 119 (96.7%) completed the inventory. Most (95) are designated stroke prevention or rapid assessment clinics. Of the 119 sites, 68 operate full time, and 39 operate less than 2.5 days per week. A total of 87.3% of the Canadian population has access to a stroke prevention service within a 1-hour drive; however, only 69.2% has access to a service that operates 5-7 days a week. Allowing provincial border crossing improves access (< 6-h drive) for those who are beyond a 6-hour drive within their home province (3.4%). Interpretation: Most Canadians have reasonable geographic access to stroke prevention services. Allowing patients to cross borders improves the existing access for many, particularly some remote communities along the Ontario-Quebec and British Columbia-Alberta borders. PMID:29472251

Geographic Variations in Arthritis Prevalence, Health-Related Characteristics, and Management - United States, 2015.

PubMed

Barbour, Kamil E; Moss, Susan; Croft, Janet B; Helmick, Charles G; Theis, Kristina A; Brady, Teresa J; Murphy, Louise B; Hootman, Jennifer M; Greenlund, Kurt J; Lu, Hua; Wang, Yan

2018-03-16

Doctor-diagnosed arthritis is a common chronic condition affecting an estimated 23% (54 million) of adults in the United States, greatly influencing quality of life and costing approximately $300 billion annually. The geographic variations in arthritis prevalence, health-related characteristics, and management among states and territories are unknown. Therefore, public health professionals need to understand arthritis in their areas to target dissemination of evidence-based interventions that reduce arthritis morbidity. 2015. The Behavioral Risk Factor Surveillance System is an annual, random-digit-dialed landline and cellular telephone survey of noninstitutionalized adults aged ≥18 years residing in the United States. Self-reported data are collected from the 50 states, the District of Columbia, Guam, and Puerto Rico. Unadjusted and age-standardized prevalences of arthritis, arthritis health-related characteristics, and arthritis management were calculated. County-level estimates were calculated using a validated statistical modeling method. In 2015, in the 50 states and the District of Columbia, median age-standardized prevalence of arthritis was 23.0% (range: 17.2%-33.6%). Modeled prevalence of arthritis varied considerably by county (range: 11.2%-42.7%). In 13 states that administered the arthritis management module, among adults with arthritis, the age-standardized median percentage of participation in a self-management education course was 14.5% (range: 9.1%-19.0%), being told by a health care provider to engage in physical activity or exercise was 58.5% (range: 52.3%-61.9%), and being told to lose weight to manage arthritis symptoms (if overweight or obese) was 44.5% (range: 35.1%-53.2%). Respondents with arthritis who lived in the quartile of states with the highest prevalences of arthritis had the highest percentages of negative health-related characteristics (i.e., arthritis-attributable activity limitations, arthritis-attributable severe joint pain, and arthritis-attributable social participation restriction; ≥14 physically unhealthy days during the past 30 days; ≥14 mentally unhealthy days during the past 30 days; obesity; and leisure-time physical inactivity) and the lowest percentage of leisure-time walking. The prevalence, health-related characteristics, and management of arthritis varied substantially across states. The modeled prevalence of arthritis varied considerably by county. The findings highlight notable geographic variability in prevalence, health-related characteristics, and management of arthritis. Targeted use of evidence-based interventions that focus on physical activity and self-management education can reduce pain and improve function and quality of life for adults with arthritis and thus might reduce these geographic disparities.

Microbial DNA fingerprinting of human fingerprints: dynamic colonization of fingertip microflora challenges human host inferences for forensic purposes

PubMed Central

Tims, Sebastian; van Wamel, Willem; Endtz, Hubert P.; Kayser, Manfred

2009-01-01

Human fingertip microflora is transferred to touched objects and may provide forensically relevant information on individual hosts, such as on geographic origins, if endogenous microbial skin species/strains would be retrievable from physical fingerprints and would carry geographically restricted DNA diversity. We tested the suitability of physical fingerprints for revealing human host information, with geographic inference as example, via microbial DNA fingerprinting. We showed that the transient exogenous fingertip microflora is frequently different from the resident endogenous bacteria of the same individuals. In only 54% of the experiments, the DNA analysis of the transient fingertip microflora allowed the detection of defined, but often not the major, elements of the resident microflora. Although we found microbial persistency in certain individuals, time-wise variation of transient and resident microflora within individuals was also observed when resampling fingerprints after 3 weeks. While microbial species differed considerably in their frequency spectrum between fingerprint samples from volunteers in Europe and southern Asia, there was no clear geographic distinction between Staphylococcus strains in a cluster analysis, although bacterial genotypes did not overlap between both continental regions. Our results, though limited in quantity, clearly demonstrate that the dynamic fingerprint microflora challenges human host inferences for forensic purposes including geographic ones. Overall, our results suggest that human fingerprint microflora is too dynamic to allow for forensic marker developments for retrieving human information. Electronic supplementary material The online version of this article (doi:10.1007/s00414-009-0352-9) contains supplementary material, which is available to authorized users. PMID:19551400

Changes in geographic variation in the uptake of cervical cancer screening in Taiwan: possible effects of "leadership style factor"?

PubMed

Chiou, Shu-Ti; Lu, Tsung-Hsueh

2014-01-01

Wennberg proposed the "practice style factor" to explain the large variations in the use of medical care. As a corollary, we propose the "leadership style factor" of the director of the city/county bureau of public health to explain changes in geographic variation in the uptake of cervical cancer screening. We first calculated the triennial Pap smear rates for women aged 30-69 years from 1997 through 2010 for each city/county in Taiwan and the rate difference and rate ratio between the highest and the lowest city/county to illustrate the geographic variation in the uptake of cervical cancer screening. We then created an expert panel to conduct a hypothesis generation process to examine the possible effects of "leadership style factors" in explaining the changes. The Pap smear rate in Taiwan as a whole was 35% in 1997 and increased to 56% in 2001, and was then stable until 2010 (55%). In 2002, the geographic variation in the Pap smear rate was the smallest, ranging from 49% in Penghu County to 63% in I-lan County, with a rate ratio of 1.28. Unfortunately, the rate ratio increased to 1.49 in 2010, the rate being lowest in Penghu County (42%) and highest in Tainan City (63%). We identified four cities/counties with unique patterns of change in Pap smear rates, which were highly associated with the leadership style of the director of the city/county bureau of public health. Despite the launch of an organized cancer screening program in Taiwan, geographic variation in the uptake of cervical cancer screening still exists and has increased during the past decade. The "leadership style factor" of the director of the city/county bureau of public health might play a plausible role in explaining the pattern of change in geographic variation in the use of cervical cancer screening in Taiwan. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Geographically Modified PageRank Algorithms: Identifying the Spatial Concentration of Human Movement in a Geospatial Network

PubMed Central

2015-01-01

A network approach, which simplifies geographic settings as a form of nodes and links, emphasizes the connectivity and relationships of spatial features. Topological networks of spatial features are used to explore geographical connectivity and structures. The PageRank algorithm, a network metric, is often used to help identify important locations where people or automobiles concentrate in the geographical literature. However, geographic considerations, including proximity and location attractiveness, are ignored in most network metrics. The objective of the present study is to propose two geographically modified PageRank algorithms—Distance-Decay PageRank (DDPR) and Geographical PageRank (GPR)—that incorporate geographic considerations into PageRank algorithms to identify the spatial concentration of human movement in a geospatial network. Our findings indicate that in both intercity and within-city settings the proposed algorithms more effectively capture the spatial locations where people reside than traditional commonly-used network metrics. In comparing location attractiveness and distance decay, we conclude that the concentration of human movement is largely determined by the distance decay. This implies that geographic proximity remains a key factor in human mobility. PMID:26437000

Geographic variation in feeding preference of a generalist herbivore: the importance of seaweed chemical defenses.

PubMed

McCarty, Amanda T; Sotka, Erik E

2013-08-01

The ecological impacts of generalist herbivores depend on feeding preferences, which can vary across and within herbivore species. Among mesoherbivores, geographic variation in host use can occur because host plants have a more restricted geographic distribution than does the herbivore, or there is local evolution in host preference, or both. We tested the role of local evolution using the marine amphipod Ampithoe longimana by rearing multiple amphipod populations from three regions (subtropical Florida, warm-temperate North Carolina and cold-temperate New England) and assaying their feeding preferences toward ten seaweeds that occur in some but not all regions. Six of the ten seaweeds produce anti-herbivore secondary metabolites, and we detected geographic variation in feeding preference toward five (Dictyota menstrualis, Dictyota ciliolata, Fucus distichus, Chondrus crispus and Padina gymnospora, but not Caulerpa sertularioides). Amphipod populations that co-occur with a chemically-rich seaweed tended to have stronger feeding preferences for that seaweed, relative to populations that do not co-occur with the seaweed. A direct test indicated that geographic variation in feeding preference toward one seaweed (D. ciliolata) is mediated by feeding tolerance for lipophilic secondary metabolites. Among the four seaweeds that produce no known secondary metabolites (Acanthophora, Ectocarpus, Gracilaria and Hincksia/Feldmannia spp.), we detected no geographic variation in feeding preference. Thus, populations are more likely to evolve greater feeding preferences for local hosts when those hosts produce secondary metabolites. Microevolution of feeding behaviors of generalist marine consumers likely depends on the availability and identity of local hosts and the strength of their chemical defenses.

Geographical Variations and Trends in Major Cancer Incidences throughout Korea during 1999-2013.

PubMed

Won, Young-Joo; Jung, Kyu-Won; Oh, Chang-Mo; Park, Eun-Hye; Kong, Hyun-Joo; Lee, Duk Hyoung; Lee, Kang Hyun

2018-01-04

We aimed to describe the temporal trends and district-level geographical variations in cancer incidences throughout Korea during 1999-2013. Data were obtained from the Korean National Cancer Incidence Database. We calculated the age-standardized cumulative cancer incidences according to sex and geographical region (metropolitan cities, provinces, and districts) for three 5-year periods (1999-2003, 2004-2008, and 2009-2013). Each quintile interval contained the same number of regions. Disease maps were created to visualize regional differences in the cancer incidences. Substantial differences in cancer incidences were observed according to district and cancer type. The largest variations between geographical regions were found for thyroid cancer among both men and women. There was little variation in the incidences of stomach, colorectal, and lung cancer according to geographical region. Substantially elevated incidences of specific cancers were observed in Jeollanam-do (thyroid); Daejeon (colorectum); Jeollanam-do, Gyeongsangbuk-do, and Chungcheongbuk-do (lung); Seocho-gu, Gangnam-gu, and Seongnam, Bundang-gu (breast and prostate); Chungcheong and Gyeongsang provinces (stomach); Ulleung-gun and the southern districts of Gyeongsangnam-do and Jeollanam-do (liver); and along the Nakdonggang River (gallbladder and biliary tract). Mapping regional cancer incidences in Korea allowed us to compare the results according to geographical region. Our results may facilitate the development of infrastructure for systematic cancer incidence monitoring, which could promote the planning and implementation of region-specific cancer management programs.

Discordant coral-symbiont structuring: factors shaping geographical variation of Symbiodinium communities in a facultative zooxanthellate coral genus, Oculina

NASA Astrophysics Data System (ADS)

Leydet, Karine Posbic; Hellberg, Michael E.

2016-06-01

Understanding the factors that help shape the association between corals and their algal symbionts, zooxanthellae ( Symbiodinium), is necessary to better understand the functional diversity and acclimatization potential of the coral host. However, most studies focus on tropical zooxanthellate corals and their obligate algal symbionts, thus limiting our full comprehension of coral-algal symbiont associations. Here, we examine algal associations in a facultative zooxanthellate coral. We survey the Symbiodinium communities associated with Oculina corals in the western North Atlantic and the Mediterranean using one clade-level marker ( psbA coding region) and three fine-scale markers ( cp23S- rDNA, b7sym15 flanking region, and b2sym17). We ask whether Oculina spp. harbor geographically different Symbiodinium communities across their geographic range and, if so, whether the host's genetics or habitat differences are correlated with this geographical variation. We found that Oculina corals harbor different Symbiodinium communities across their geographical range. Of the habitat differences (including chlorophyll a concentration and depth), sea surface temperature is better correlated with this geographical variation than the host's genetics, a pattern most evident in the Mediterranean. Our results suggest that although facultative zooxanthellate corals may be less dependent on their algal partners compared to obligate zooxanthellate corals, the Symbiodinium communities that they harbor may nevertheless reflect acclimatization to environmental variation among habitats.

Immunogenetics as a tool in anthropological studies

PubMed Central

Sanchez-Mazas, Alicia; Fernandez-Viña, Marcelo; Middleton, Derek; Hollenbach, Jill A; Buhler, Stéphane; Di, Da; Rajalingam, Raja; Dugoujon, Jean-Michel; Mack, Steven J; Thorsby, Erik

2011-01-01

The genes coding for the main molecules involved in the human immune system – immunoglobulins, human leucocyte antigen (HLA) molecules and killer-cell immunoglobulin-like receptors (KIR) – exhibit a very high level of polymorphism that reveals remarkable frequency variation in human populations. ‘Genetic marker’ (GM) allotypes located in the constant domains of IgG antibodies have been studied for over 40 years through serological typing, leading to the identification of a variety of GM haplotypes whose frequencies vary sharply from one geographic region to another. An impressive diversity of HLA alleles, which results in amino acid substitutions located in the antigen-binding region of HLA molecules, also varies greatly among populations. The KIR differ between individuals according to both gene content and allelic variation, and also display considerable population diversity. Whereas the molecular evolution of these polymorphisms has most likely been subject to natural selection, principally driven by host–pathogen interactions, their patterns of genetic variation worldwide show significant signals of human geographic expansion, demographic history and cultural diversification. As current developments in population genetic analysis and computer simulation improve our ability to discriminate among different – either stochastic or deterministic – forces acting on the genetic evolution of human populations, the study of these systems shows great promise for investigating both the peopling history of modern humans in the time since their common origin and human adaptation to past environmental (e.g. pathogenic) changes. Therefore, in addition to mitochondrial DNA, Y-chromosome, microsatellites, single nucleotide polymorphisms and other markers, immunogenetic polymorphisms represent essential and complementary tools for anthropological studies. PMID:21480890

Cheek tooth morphology and ancient mitochondrial DNA of late Pleistocene horses from the western interior of North America: Implications for the taxonomy of North American Late Pleistocene Equus

PubMed Central

Rodrigues, Antonia T.; Theodor, Jessica M.; Kooyman, Brian P.; Yang, Dongya Y.; Speller, Camilla F.

2017-01-01

Horses were a dominant component of North American Pleistocene land mammal communities and their remains are well represented in the fossil record. Despite the abundant material available for study, there is still considerable disagreement over the number of species of Equus that inhabited the different regions of the continent and on their taxonomic nomenclature. In this study, we investigated cheek tooth morphology and ancient mtDNA of late Pleistocene Equus specimens from the Western Interior of North America, with the objective of clarifying the species that lived in this region prior to the end-Pleistocene extinction. Based on the morphological and molecular data analyzed, a caballine (Equus ferus) and a non-caballine (E. conversidens) species were identified from different localities across most of the Western Interior. A second non-caballine species (E. cedralensis) was recognized from southern localities based exclusively on the morphological analyses of the cheek teeth. Notably the separation into caballine and non-caballine species was observed in the Bayesian phylogenetic analysis of ancient mtDNA as well as in the geometric morphometric analyses of the upper and lower premolars. Teeth morphologically identified as E. conversidens that yielded ancient mtDNA fall within the New World stilt-legged clade recognized in previous studies and this is the name we apply to this group. Geographic variation in morphology in the caballine species is indicated by statistically different occlusal enamel patterns in the specimens from Bluefish Caves, Yukon Territory, relative to the specimens from the other geographic regions. Whether this represents ecomorphological variation and/or a certain degree of geographic and genetic isolation of these Arctic populations requires further study. PMID:28817644

Cheek tooth morphology and ancient mitochondrial DNA of late Pleistocene horses from the western interior of North America: Implications for the taxonomy of North American Late Pleistocene Equus.

PubMed

Barrón-Ortiz, Christina I; Rodrigues, Antonia T; Theodor, Jessica M; Kooyman, Brian P; Yang, Dongya Y; Speller, Camilla F

2017-01-01

Horses were a dominant component of North American Pleistocene land mammal communities and their remains are well represented in the fossil record. Despite the abundant material available for study, there is still considerable disagreement over the number of species of Equus that inhabited the different regions of the continent and on their taxonomic nomenclature. In this study, we investigated cheek tooth morphology and ancient mtDNA of late Pleistocene Equus specimens from the Western Interior of North America, with the objective of clarifying the species that lived in this region prior to the end-Pleistocene extinction. Based on the morphological and molecular data analyzed, a caballine (Equus ferus) and a non-caballine (E. conversidens) species were identified from different localities across most of the Western Interior. A second non-caballine species (E. cedralensis) was recognized from southern localities based exclusively on the morphological analyses of the cheek teeth. Notably the separation into caballine and non-caballine species was observed in the Bayesian phylogenetic analysis of ancient mtDNA as well as in the geometric morphometric analyses of the upper and lower premolars. Teeth morphologically identified as E. conversidens that yielded ancient mtDNA fall within the New World stilt-legged clade recognized in previous studies and this is the name we apply to this group. Geographic variation in morphology in the caballine species is indicated by statistically different occlusal enamel patterns in the specimens from Bluefish Caves, Yukon Territory, relative to the specimens from the other geographic regions. Whether this represents ecomorphological variation and/or a certain degree of geographic and genetic isolation of these Arctic populations requires further study.

Geographic Variation in Opioid Prescribing in the U.S.

PubMed Central

McDonald, Douglas C.; Carlson, Kenneth; Izrael, David

2012-01-01

Estimates of geographic variation among states and counties in the prevalence of opioid prescribing are developed using data from a large (135M) representative national sample of opioid prescriptions dispensed during 2008 by 37,000 retail pharmacies. Statistical analyses are used to estimate the extent to which county variation is explained by characteristics of resident populations, their healthcare utilization, proxy measures of morbidity, availability of healthcare resources, and prescription monitoring laws. Geographic variation in prevalence of prescribed opioids is large, greater than variation observed for other healthcare services. Counties having the highest prescribing rates for opioids were disproportionately located in Appalachia and in Southern and Western states. The number of available physicians was by far the strongest predictor of amounts prescribed, but only one-third of county variation is explained by the combination of all measured factors. Wide variation in prescribing opioids reflects weak consensus regarding the appropriate use of opioids for treating pain, especially chronic non-cancer pain. Patients’ demands for treatment have increased, more potent opioids have become available, an epidemic of abuse has emerged, and calls for increased government regulation are growing. Greater guidance, education and training in opioid prescribing are needed for clinicians to support appropriate prescribing practices. Perspective Wide geographic variation that does not reflect differences in the prevalence of injuries, surgeries, or conditions requiring analgesics raises questions about opioid prescribing practices. Low prescription rates may indicate under-treatment, while high rates may indicate overprescribing and insufficient attention to risks of misuse. PMID:23031398

First impressions: geographic variation in media messages during the first phase of ACA implementation.

PubMed

Gollust, Sarah E; Barry, Colleen L; Niederdeppe, Jeff; Baum, Laura; Fowler, Erika Franklin

2014-12-01

Many Americans will learn about the implementation of the Patient Protection and Affordable Care Act (ACA) through the mass media. We examined geographic variation in the volume and content of mass media during the initial two-week rollout of the new health insurance marketplaces in October 2013 across 210 US media markets, using data from the Wesleyan Media Project. We found substantial geographic variation in the volume and tone of insurance product advertisements, political advertisements, and news coverage of the ACA marketplaces. News coverage of the ACA airing in media markets located in states operating federal or partnership marketplaces was more negative than coverage airing in markets located in states running their own marketplaces. Intrastate variation in media volume and content was also substantial and appears distinguishable from the local political climate. Variation in exposure to media messages likely affects public sentiment regarding the ACA and could contribute to geographic differences in insurance enrollment and public perceptions of US health care options. Researchers and policy makers evaluating the implementation of the ACA-and insurance enrollment in the marketplaces in particular-should consider addressing media influences. Copyright © 2014 by Duke University Press.

Inter- and intraspecific mitochondrial DNA variation in North American bears (Ursus)

USGS Publications Warehouse

Cronin, Matthew A.; Amstrup, Steven C.; Garner, Gerald W.; Vyse, Ernest R.

1991-01-01

We assessed mitochondrial DNA variation in North American black bears (Ursus americanus), brown bears (Ursus arctos), and polar bears (Ursus maritimus). Divergent mitochondrial DNA haplotypes (0.05 base substitutions per nucleotide) were identified in populations of black bears from Montana and Oregon. In contrast, very similar haplotypes occur in black bears across North America. This discordance of haplotype phylogeny and geographic distribution indicates that there has been maintenance of polymorphism and considerable gene flow throughout the history of the species. Intraspecific mitochondrial DNA sequence divergence in brown bears and polar bears is lower than in black bears. The two morphological forms of U. arctos, grizzly and coastal brown bears, are not in distinct mtDNA lineages. Interspecific comparisons indicate that brown bears and polar bears share similar mitochondrial DNA (0.023 base substitutions per nucleotide) which is quite divergent (0.078 base substitutions per nucleotide) from that of black bears. High mitochondrial DNA divergence within black bears and paraphyletic relationships of brown and polar bear mitochondrial DNA indicate that intraspecific variation across species' ranges should be considered in phylogenetic analyses of mitochondrial DNA.

Parallel Geographic Variation in Drosophila melanogaster

PubMed Central

Reinhardt, Josie A.; Kolaczkowski, Bryan; Jones, Corbin D.; Begun, David J.; Kern, Andrew D.

2014-01-01

Drosophila melanogaster, an ancestrally African species, has recently spread throughout the world, associated with human activity. The species has served as the focus of many studies investigating local adaptation relating to latitudinal variation in non-African populations, especially those from the United States and Australia. These studies have documented the existence of shared, genetically determined phenotypic clines for several life history and morphological traits. However, there are no studies designed to formally address the degree of shared latitudinal differentiation at the genomic level. Here we present our comparative analysis of such differentiation. Not surprisingly, we find evidence of substantial, shared selection responses on the two continents, probably resulting from selection on standing ancestral variation. The polymorphic inversion In(3R)P has an important effect on this pattern, but considerable parallelism is also observed across the genome in regions not associated with inversion polymorphism. Interestingly, parallel latitudinal differentiation is observed even for variants that are not particularly strongly differentiated, which suggests that very large numbers of polymorphisms are targets of spatially varying selection in this species. PMID:24610860

Does advertisement call variation coincide with genetic variation in the genetically diverse frog taxon currently known as Leptodactylus fuscus (Amphibia: Leptodactylidae)?

PubMed

Heyer, W Ronald; Reid, Yana R

2003-03-01

The frog Leptodactylus fuscus is found throughout much of South America in open and disturbed habitats. Previous study of genetic differentiation in L. fuscus demonstrated that there was lack of genetic exchange among population units consistent with multiple species, rather than a single species. We examine advertisement vocalizations of L. fuscus to determine whether call variation coincides with genetic differentiation. Calls were analyzed for 32 individual frogs from 25 localities throughout the distributional range of L. fuscus. Although there is variation in calls among geographic samples, call variation is not concordant with genetic variation or geographic distance and the call variation observed is less than that typically found among other closely related species of Leptodactylus. This study is an example of the rare pattern of strong genetic differentiation unaccompanied by salient differences in advertisement calls. The relative infrequency of this pattern as currently understood may only reflect the lack of detailed analyses of genetic and acoustic differentiation within population systems currently understood as single species with substantial geographic distributions.

Parallel Evolution of Copy-Number Variation across Continents in Drosophila melanogaster.

PubMed

Schrider, Daniel R; Hahn, Matthew W; Begun, David J

2016-05-01

Genetic differentiation across populations that is maintained in the presence of gene flow is a hallmark of spatially varying selection. In Drosophila melanogaster, the latitudinal clines across the eastern coasts of Australia and North America appear to be examples of this type of selection, with recent studies showing that a substantial portion of the D. melanogaster genome exhibits allele frequency differentiation with respect to latitude on both continents. As of yet there has been no genome-wide examination of differentiated copy-number variants (CNVs) in these geographic regions, despite their potential importance for phenotypic variation in Drosophila and other taxa. Here, we present an analysis of geographic variation in CNVs in D. melanogaster. We also present the first genomic analysis of geographic variation for copy-number variation in the sister species, D. simulans, in order to investigate patterns of parallel evolution in these close relatives. In D. melanogaster we find hundreds of CNVs, many of which show parallel patterns of geographic variation on both continents, lending support to the idea that they are influenced by spatially varying selection. These findings support the idea that polymorphic CNVs contribute to local adaptation in D. melanogaster In contrast, we find very few CNVs in D. simulans that are geographically differentiated in parallel on both continents, consistent with earlier work suggesting that clinal patterns are weaker in this species. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Quantitative analysis of the impacts of terrestrial environmental factors on precipitation variation over the Beibu Gulf Economic Zone in Coastal Southwest China

PubMed Central

Zhao, Yinjun; Deng, Qiyu; Lin, Qing; Cai, Chunting

2017-01-01

Taking the Guangxi Beibu Gulf Economic Zone as the study area, this paper utilizes the geographical detector model to quantify the feedback effects from the terrestrial environment on precipitation variation from 1985 to 2010 with a comprehensive consideration of natural factors (forest coverage rate, vegetation type, terrain, terrestrial ecosystem types, land use and land cover change) and social factors (population density, farmland rate, GDP and urbanization rate). First, we found that the precipitation trend rate in the Beibu Gulf Economic Zone is between −47 and 96 mm/10a. Second, forest coverage rate change (FCRC), urbanization rate change (URC), GDP change (GDPC) and population density change (PDC) have a larger contribution to precipitation change through land-surface feedback, which makes them the leading factors. Third, the human element is found to primarily account for the precipitation changes in this region, as humans are the active media linking and enhancing these impact factors. Finally, it can be concluded that the interaction of impact factor pairs has a significant effect compared to the corresponding single factor on precipitation changes. The geographical detector model offers an analytical framework to reveal the terrestrial factors affecting the precipitation change, which gives direction for future work on regional climate modeling and analyses. PMID:28294123

Chemical Composition of Juniperus communis L. Cone Essential Oil and Its Variability among Wild Populations in Kosovo.

PubMed

Hajdari, Avni; Mustafa, Behxhet; Nebija, Dashnor; Miftari, Elheme; Quave, Cassandra L; Novak, Johannes

2015-11-01

Ripe cones of Juniperus communis L. (Cupressaceae) were collected from five wild populations in Kosovo, with the aim of investigating the chemical composition and natural variation of essential oils between and within wild populations. Ripe cones were collected, air dried, crushed, and the essential oils obtained by hydrodistillation. The essential-oil constituents were identified by GC-FID and GC/MS analyses. The yield of essential oil differed depending on the population origins and ranged from 0.4 to 3.8% (v/w, based on the dry weight). In total, 42 compounds were identified in the essential oils of all populations. The principal components of the cone-essential oils were α-pinene, followed by β-myrcene, sabinene, and D-limonene. Taking into consideration the yield and chemical composition, the essential oil originating from various collection sites in Kosovo fulfilled the minimum requirements for J. communis essential oils of the European Pharmacopoeia. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used to determine the influence of the geographical variations on the essential-oil composition. These statistical analyses suggested that the clustering of populations was not related to their geographic location, but rather appeared to be linked to local selective forces acting on the chemotype diversity. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

Prevalence of maedi-visna infection in culled ewes in Alberta

PubMed Central

Fournier, Dominique; Campbell, John R.

2006-01-01

Abstract Maedi-visna (MV) is a relatively common chronic infection of sheep in North America resulting in economic loss to the sheep industry. The objectives of this study were to: 1) measure the prevalence of MV infection in culled ewes in Alberta, by histologic examination (lungs and udder) and serologic testing using an agar gel immunodiffusion (AGID) test, 2) examine any geographic differences in its prevalence in the province, 3) evaluate the level of agreement between histopathologic examination and serologic testing, 4) grade the lesions and correlate the serologic results with the presence of severe histological lesions, and 5) correlate the presence of histological lesions in the lungs and udder in the same animal. Based on histologic findings, the prevalence of MV was 26.8%, compared with 13.0% using serologic testing. There were no significant geographical differences in prevalence, fair agreement (kappa = 42.0%) between histopathologic and serologic results, and poor agreement (kappa = 11.5%) between the presence of lung and udder histological lesions within the same animal. This study indicates that MV is relatively common in culled ewes in Alberta, with no significant geographic variation. The poor sensitivity of the AGID test, compared with histologic examination, should be taken into consideration when interpreting serologic results. PMID:16734372

Geographic distribution of childhood diabetes and obesity relative to the supply of pediatric endocrinologists in the United States.

PubMed

Lee, Joyce M; Davis, Matthew M; Menon, Ram K; Freed, Gary L

2008-03-01

To determine the geographic distribution of childhood diabetes and obesity relative to the supply of US pediatric endocrinologists. Estimation of observed and "index" ratios of children with diabetes (by region and division) and obesity (body mass index >/=95th % for age and sex) (by region and state) to board-certified pediatric endocrinologists. At the national level, the ratio of children with diabetes to pediatric endocrinologists is 290:1, and the ratio of obese children to pediatric endocrinologists is 17,741:1. Ratios of children with diabetes to pediatric endocrinologists in the Midwest (370:1), South (335:1), and West (367:1) are twice as high as in the Northeast (144:1). Across states, there is up to a 19-fold difference in the observed ratios of obese children to pediatric endocrinologists. Under conditions of equitably distributed endocrinologist supply, variation across states would be mitigated considerably. The distribution of children with diabetes and obesity does not parallel the distribution of pediatric endocrinologists in the United States, due largely to geographic disparities in endocrinologist supply. Given the large burden of obese children to endocrinologists, multidisciplinary models of care delivery are essential for the US health care system to address the needs of children with diabetes and obesity.

Geographic differences in fractures among women

PubMed Central

Litwic, Anna; Edwards, Mark; Cooper, Cyrus; Dennison, Elaine

2013-01-01

Osteoporotic fracture is associated with considerable morbidity and mortality in women throughout the world. However, significant variation in hip fracture rates among women from different nations have been observed, and are likely to represent a combination of real and apparent differences due to ascertainment bias. Higher rates are observed in Caucasian women, with lowest rates observed in black women and intermediate rates among Asian women. These differences are likely to represent a combination of genetic and environmental differences; for example, among European women, the highest fracture rates are observed in Scandinavian women where vitamin D insufficiency is common. In all groups, an expansion in absolute fracture numbers is anticipated due to demographic changes. PMID:23181532

Geographic variability of adherence to occupational injury treatment guidelines.

PubMed

Trujillo, Antonio J; Heins, Sara E; Anderson, Gerard F; Castillo, Renan C

2014-12-01

To determine the geographic variability and relationship between six occupational injury practice guidelines. Guidelines were developed by an expert panel and evaluated using workers' compensation claims data from a large, national insurance company (1999 to 2010). Percentage compliance for each guideline was adjusted for age and sex using linear regression and mapped by hospital referral region. Regions with the lowest compliance were identified, and correlations between guidelines were calculated. Compliance to the unnecessary home care guideline showed the lowest geographic variation (interquartile range: 97.3 to 99.0), and inappropriate shoulder bracing showed the highest variation (interquartile range: 77.7 to 90.8). Correlation between the guidelines was weak and not always positive. Different guidelines showed different degrees of geographic variation. Lack of correlation between guidelines suggests that these indicators were not associated with a single underlying health care quality or patient severity construct.

Marine turtle mitogenome phylogenetics and evolution.

PubMed

Duchene, Sebastián; Frey, Amy; Alfaro-Núñez, Alonzo; Dutton, Peter H; Thomas P Gilbert, M; Morin, Phillip A

2012-10-01

The sea turtles are a group of cretaceous origin containing seven recognized living species: leatherback, hawksbill, Kemp's ridley, olive ridley, loggerhead, green, and flatback. The leatherback is the single member of the Dermochelidae family, whereas all other sea turtles belong in Cheloniidae. Analyses of partial mitochondrial sequences and some nuclear markers have revealed phylogenetic inconsistencies within Cheloniidae, especially regarding the placement of the flatback. Population genetic studies based on D-Loop sequences have shown considerable structuring in species with broad geographic distributions, shedding light on complex migration patterns and possible geographic or climatic events as driving forces of sea-turtle distribution. We have sequenced complete mitogenomes for all sea-turtle species, including samples from their geographic range extremes, and performed phylogenetic analyses to assess sea-turtle evolution with a large molecular dataset. We found variation in the length of the ATP8 gene and a highly variable site in ND4 near a proton translocation channel in the resulting protein. Complete mitogenomes show strong support and resolution for phylogenetic relationships among all sea turtles, and reveal phylogeographic patterns within globally-distributed species. Although there was clear concordance between phylogenies and geographic origin of samples in most taxa, we found evidence of more recent dispersal events in the loggerhead and olive ridley turtles, suggesting more recent migrations (<1 Myr) in these species. Overall, our results demonstrate the complexity of sea-turtle diversity, and indicate the need for further research in phylogeography and molecular evolution. Published by Elsevier Inc.

Variations in Obesity Rates between US Counties: Impacts of Activity Access, Food Environments, and Settlement Patterns.

PubMed

Congdon, Peter

2017-09-07

There is much ongoing research about the effect of the urban environment as compared with individual behaviour on growing obesity levels, including food environment, settlement patterns (e.g., sprawl, walkability, commuting patterns), and activity access. This paper considers obesity variations between US counties, and delineates the main dimensions of geographic variation in obesity between counties: by urban-rural status, by region, by area poverty status, and by majority ethnic group. Available measures of activity access, food environment, and settlement patterns are then assessed in terms of how far they can account for geographic variation. A county level regression analysis uses a Bayesian methodology that controls for spatial correlation in unmeasured area risk factors. It is found that environmental measures do play a significant role in explaining geographic contrasts in obesity.

Variations in Obesity Rates between US Counties: Impacts of Activity Access, Food Environments, and Settlement Patterns

PubMed Central

2017-01-01

There is much ongoing research about the effect of the urban environment as compared with individual behaviour on growing obesity levels, including food environment, settlement patterns (e.g., sprawl, walkability, commuting patterns), and activity access. This paper considers obesity variations between US counties, and delineates the main dimensions of geographic variation in obesity between counties: by urban-rural status, by region, by area poverty status, and by majority ethnic group. Available measures of activity access, food environment, and settlement patterns are then assessed in terms of how far they can account for geographic variation. A county level regression analysis uses a Bayesian methodology that controls for spatial correlation in unmeasured area risk factors. It is found that environmental measures do play a significant role in explaining geographic contrasts in obesity. PMID:28880209

Google Earth as a (Not Just) Geography Education Tool

ERIC Educational Resources Information Center

Patterson, Todd C.

2007-01-01

The implementation of Geographic Information Science (GIScience) applications and discussion of GIScience-related themes are useful for teaching fundamental geographic and technological concepts. As one of the newest geographic information tools available on the World Wide Web, Google Earth has considerable potential to enhance methods for…

Geographic Variations in Cost of Living: Associations with Family and Child Well-Being

ERIC Educational Resources Information Center

Chien, Nina C.; Mistry, Rashmita S.

2013-01-01

The effects of geographic variations in cost of living and family income on children's academic achievement and social competence in first grade (mean age = 86.9 months) were examined, mediated through material hardship, parental investments, family stress, and school resources. Using data from the Early Childhood Longitudinal Study-Kindergarten…

Geographic Variation in Mortality Among Children and Adolescents Diagnosed with Cancer in Tennessee: Does Race Matter?

PubMed Central

Lindley, Lisa C.; Oyana, Tonny J.

2017-01-01

Cancer is one of the leading causes of death among children in the United States. Previous research has examined geographic variation in cancer incidence and survival, but the geographic variation in mortality among children and adolescents is not as well understood. The purpose of this study was to investigate geographic variation by race in mortality among children and adolescents diagnosed with cancer in Tennessee. Using an innovative combination of spatial and non-spatial analysis techniques with data from the 2004–2011 Tennessee Cancer Registry, pediatric deaths were mapped and the affect of race on the proximity to rural areas and clusters of mortality were explored with multivariate regressions. The findings revealed that African American children and adolescents in Tennessee were more likely than their counterparts of other races to reside in rural areas with close proximity to mortality clusters of children and adolescents with a cancer. Findings have clinical implications for pediatric oncology nurses regarding the delivery of supportive care at end of life for rural African American children and adolescents. PMID:26458417

Geographic Variation in Maternal Smoking during Pregnancy in the Missouri Adolescent Female Twin Study (MOAFTS)

PubMed Central

Lian, Min; Madden, Pamela A.; Lynskey, Michael T.; Colditz, Graham A.; Lessov-Schlaggar, Christina N.; Schootman, Mario; Heath, Andrew C.

2016-01-01

Objective Despite well-known adverse health effects of maternal smoking during pregnancy (MSP), it is still unclear if MSP varies geographically and if neighborhood socioeconomic deprivation (SED) plays an important role in MSP. This study aims to investigate small-area geographic variation in MSP and examine the association of SED with MSP. Methods The Missouri Adolescent Female Twin Study (MOAFTS) is a cohort study of female like-sex twins born in Missouri to Missouri-resident parents during 1975–1985. Biological mothers completed a baseline interview in 1995–1998 and reported MSP with the twins. Residential address of the mother at birth was geocoded. We developed a census tract-level SED index using a common factor approach based on 21 area-level socioeconomic variables from the 1980 Census data. Multilevel logistic regressions estimated geographic heterogeneity (random effect) in MSP and the odds ratios (ORs, fixed effects) of neighborhood SED associated with MSP. Results Of 1658 MOAFTS mothers, 35.2% reported any MSP and 21.9% reported MSP beyond the first trimester. Neighborhood SED was associated with any MSP (the highest vs. the lowest quartile: OR = 1.90, 95% confidence interval [CI] = 1.40–2.57, Ptrend<0.001) and MSP beyond the first trimester (OR = 1.98, 95% CI = 1.38–2.85, Ptrend = 0.002) in unadjusted analyses. After adjusting for individual covariates (demographics, socioeconomic conditions, alcohol use, and parents’ cohabitation), neighborhood SED was not associated with MSP, but geographic variation still persisted in MSP (variance = 0.41, P = 0.003) and in MSP beyond the first trimester (variance = 0.82, P<0.001). Conclusions Neighborhood SED was associated with MSP in unadjusted analyses but this association could be explained by individual socioeconomic conditions. Nonetheless, significant geographic variation in MSP persisted and was not accounted for by differences in neighborhood SED. To develop effective interventions to reduce MSP, further studies are necessary to explore underlying reasons for its geographic variation. PMID:27100091

Geographic variation in one-year recurrent ischemic stroke rates for elderly Medicare beneficiaries in the USA.

PubMed

Allen, Norrina B; Holford, Theodore R; Bracken, Michael B; Goldstein, Larry B; Howard, George; Wang, Yun; Lichtman, Judith H

2010-01-01

While geographic disparities in stroke mortality are well documented, there are no data describing geographic variation in recurrent stroke. Accordingly, we evaluated geographic variations in 1-year recurrent ischemic stroke rates in the USA with adjustment for patient characteristics. One-year recurrent stroke rates for ischemic stroke (International Classification of Diseases, 9th Revision codes 433, 434 and 436) following hospital discharge were calculated by county for all fee-for-service Medicare beneficiaries from 2000 to 2002. The rates were standardized and smoothed using a bayesian conditional autoregressive model that was risk-standardized for patients' age, gender, race/ethnicity, prior hospitalizations, Deyo comorbidity score, acute myocardial infarction, congestive heart failure, diabetes, hypertension, dementia, cancer, chronic obstructive pulmonary disease and obesity. The overall 1-year recurrent stroke rate was 9.4% among 895,916 ischemic stroke patients (mean age: 78 years; 56.6% women; 86.6% White, 9.7% Black and 1.2% Latino/Hispanic). The rates varied by geographic region and were highest in the South and in parts of the West and Midwest. Regional variation was present for all racial/ethnic subgroups and persisted after adjustment for individual patient characteristics. Almost 1 in 10 hospitalized ischemic stroke patients was readmitted for an ischemic stroke within 1 year. There was heterogeneity in recurrence patterns by geographic region. Further work is needed to understand the reasons for this regional variability. Copyright 2010 S. Karger AG, Basel.

Geographic variation in genetic and demographic performance: new insights from an old biogeographical paradigm.

PubMed

Pironon, Samuel; Papuga, Guillaume; Villellas, Jesús; Angert, Amy L; García, María B; Thompson, John D

2017-11-01

The 'centre-periphery hypothesis' (CPH) is a long-standing postulate in ecology that states that genetic variation and demographic performance of a species decrease from the centre to the edge of its geographic range. This hypothesis is based on an assumed concordance between geographical peripherality and ecological marginality such that environmental conditions become harsher towards the limits of a species range. In this way, the CPH sets the stage for understanding the causes of distribution limits. To date, no study has examined conjointly the consistency of these postulates. In an extensive literature review we discuss the birth and development of the CPH and provide an assessment of the CPH by reviewing 248 empirical studies in the context of three main themes. First, a decrease in species occurrence towards their range limits was observed in 81% of studies, while only 51% demonstrated reduced abundance of individuals. A decline in genetic variation, increased differentiation among populations and higher rates of inbreeding were demonstrated by roughly one in two studies (47, 45 and 48%, respectively). However, demographic rates, size and population performance less often followed CPH expectations (20-30% of studies). We highlight the impact of important methodological, taxonomic, and biogeographical biases on such validation rates. Second, we found that geographic and ecological marginality gradients are not systematically concordant, which casts doubt on the reliability of a main assumption of the CPH. Finally, we attempt to disentangle the relative contribution of geographical, ecological and historical processes on the spatial distribution of genetic and demographic parameters. While ecological marginality gradients explain variation in species' demographic performance better than geographic gradients, contemporary and historical factors may contribute interactively to spatial patterns of genetic variation. We thereby propose a framework that integrates species' ecological niche characteristics together with current and past range structure to investigate spatial patterns of genetic and demographic variation across species ranges. © 2016 Cambridge Philosophical Society.

Relative contributions of neutral and non-neutral processes to clinal variation in calyx lobe length in the series Sakawanum (Asarum: Aristolochiaceae).

PubMed

Takahashi, Daiki; Teramine, Tsutomu; Sakaguchi, Shota; Setoguchi, Hiroaki

2018-01-25

Clines, the gradual variation in measurable traits along a geographical axis, play a major role in evolution and can contribute to our understanding of the relative roles of selective and neutral process in trait variation. Using genetic and morphological analyses, the relative contributions of neutral and non-neutral processes were explored to infer the evolutionary history of species of the series Sakawanum (genus Asarum), which shows significant clinal variation in calyx lobe length. A total of 27 populations covering the natural geographical distribution of the series Sakawanum were sampled. Six nuclear microsatellite markers were used to investigate genetic structure and genetic diversity. The lengths of calyx lobes of multiple populations were measured to quantify their geographical and taxonomic differentiation. To detect the potential impact of selective pressure, morphological differentiation was compared with genetic differentiation (QCT-FST comparison). Average calyx lobe length of A. minamitanianum was 124.11 mm, while that of A. costatum was 13.80 mm. Though gradually changing along the geographical axis within series, calyx lobe lengths were significantly differentiated among the taxa. Genetic differentiation between taxa was low (FST = 0.099), but a significant geographical structure along the morphological cline was detected. Except for one taxon pair, pairwise QCT values were significantly higher than the neutral genetic measures of FST and G'ST. Divergent selection may have driven the calyx lobe length variation in series Sakawanum taxa, although the underlying mechanism is still not clear. The low genetic differentiation indicates recent divergence and/or gene flows between geographically close taxa. These neutral processes would also affect the clinal variation in calyx lobe lengths. Overall, this study implies the roles of population history and divergent selection in shaping the current cline of a flower trait in the series Sakawanum. © The Author(s) 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Issues Surrounding the Use of Virtual Reality in Geographic Education

ERIC Educational Resources Information Center

Lisichenko, Richard

2015-01-01

As with all classroom innovations intended to improve geographic education, the adoption of virtual reality (VR) poses issues for consideration prior to endorsing its use. Of these, effectiveness, implementation, and safe use need to be addressed. Traditionally, sense of place, geographic knowledge, and firsthand experiences provided by field…

Geographical Gradients in Argentinean Terrestrial Mammal Species Richness and Their Environmental Correlates

PubMed Central

Márquez, Ana L.; Real, Raimundo; Kin, Marta S.; Guerrero, José Carlos; Galván, Betina; Barbosa, A. Márcia; Olivero, Jesús; Palomo, L. Javier; Vargas, J. Mario; Justo, Enrique

2012-01-01

We analysed the main geographical trends of terrestrial mammal species richness (SR) in Argentina, assessing how broad-scale environmental variation (defined by climatic and topographic variables) and the spatial form of the country (defined by spatial filters based on spatial eigenvector mapping (SEVM)) influence the kinds and the numbers of mammal species along these geographical trends. We also evaluated if there are pure geographical trends not accounted for by the environmental or spatial factors. The environmental variables and spatial filters that simultaneously correlated with the geographical variables and SR were considered potential causes of the geographic trends. We performed partial correlations between SR and the geographical variables, maintaining the selected explanatory variables statistically constant, to determine if SR was fully explained by them or if a significant residual geographic pattern remained. All groups and subgroups presented a latitudinal gradient not attributable to the spatial form of the country. Most of these trends were not explained by climate. We used a variation partitioning procedure to quantify the pure geographic trend (PGT) that remained unaccounted for. The PGT was larger for latitudinal than for longitudinal gradients. This suggests that historical or purely geographical causes may also be relevant drivers of these geographical gradients in mammal diversity. PMID:23028254

Geographic Variation Immediate and Delayed Breast Reconstruction Utilization in Ontario, Canada and Plastic Surgeon Availability: A Population-Based Observational Study.

PubMed

Platt, Jennica; Zhong, Toni; Moineddin, Rahim; Booth, Gillian L; Easson, Alexandra M; Fernandes, Kimberly; Gozdyra, Peter; Baxter, Nancy N

2015-08-01

Utilization of breast reconstruction (BR) is low in many jurisdictions. We studied the geographical and surgical workforce factors that contribute to access and use of BR using a small area analysis approach with a geographical unit of analysis. We linked administrative data from Ontario Canada to calculate the age-standardized rates for immediate BR (IBR) (same time as mastectomy) between 2002 and 2011, and delayed BR (DBR) (within 3 years of mastectomy) for each county. The influence of plastic surgeon access on variation in county rates of BR was examined using Poisson random effects models. 12,663 women underwent mastectomy in Ontario; 2,948 had BR within 3 years (23.3%). Over 50% of the counties had no access to any plastic surgeon. County IBR rates ranged from 0 to 21.5%; plastic surgeon access explained 46% of geographic variation (p<0.0001). IBR rates in counties with very low, low, and moderate access to plastic surgeons were significantly less than counties with high access (relative rate [RR] 0.48 [95% confidence interval (CI) 0.35-0.66], RR 0.61 [CI 0.43-0.87] and RR 0.70 [CI 0.52-0.96], respectively) after adjusting for age and county socioeconomic characteristics. For DBR, while there was less geographic variation, very low access counties demonstrated reduced rates (RR 0.60 [CI 0.47-0.76]). Geographic access to a plastic surgeon is a major determinant of BR. Targeted interventions for regions without high access to plastic surgeons may improve overall rates and reduce geographic disparities in care, particularly for IBR.

Clues to unraveling the coral species problem: distinguishing species from geographic variation in Porites across the Pacific with molecular markers and microskeletal traits

PubMed Central

Wellington, Gerrard M.; Fox, George E.; Toonen, Robert J.

2015-01-01

Morphological variation in the geographically widespread coral Porites lobata can make it difficult to distinguish from other massive congeneric species. This morphological variation could be attributed to geographic variability, phenotypic plasticity, or a combination of such factors. We examined genetic and microscopic morphological variability in P. lobata samples from the Galápagos, Easter Island, Tahiti, Fiji, Rarotonga, and Australia. Panamanian P. evermanni specimens were used as a previously established distinct outgroup against which to test genetic and morphological methods of discrimination. We employed a molecular analysis of variance (AMOVA) based on ribosomal internal transcribed spacer region (ITS) sequence, principal component analysis (PCA) of skeletal landmarks, and Mantel tests to compare genetic and morphological variation. Both genetic and morphometric methods clearly distinguished P. lobata and P. evermanni, while significant genetic and morphological variance was attributed to differences among geographic regions for P. lobata. Mantel tests indicate a correlation between genetic and morphological variation for P. lobata across the Pacific. Here we highlight landmark morphometric measures that correlate well with genetic differences, showing promise for resolving species of Porites, one of the most ubiquitous yet challenging to identify architects of coral reefs. PMID:25674364

Dental Workforce Availability and Dental Services Utilization in Appalachia: A Geospatial Analysis

PubMed Central

Feng, Xue; Sambamoorthi, Usha; Wiener, R. Constance

2016-01-01

Objectives There is considerable variation in dental services utilization across Appalachian counties, and a plausible explanation is that individuals in some geographical areas do not utilize dental care due to dental workforce shortage. We conducted an ecological study on dental workforce availability and dental services utilization in Appalachia. Methods We derived county-level (n = 364) data on demographic, socio-economic characteristics and dental services utilization in Appalachia from the 2010 Behavioral Risk Factor Surveillance System (BRFSS) using person-level data. We obtained county-level dental workforce availability and physician-to-population ratio estimates from Area Health Resource File, and linked them to the county-level BRFSS data. The dependent variable was the proportion using dental services within the last year in each county (ranging from 16.6% to 91.0%). We described the association between dental workforce availability and dental services utilization using ordinary least squares regression and spatial regression techniques. Spatial analyses consisted of bivariate Local Indicators of Spatial Association (LISA) and geographically weighted regression (GWR). Results Bivariate LISA showed that counties in the central and southern Appalachian regions had significant (p < .05) low-low spatial clusters (low dental workforce availability, low percent dental services utilization). GWR revealed considerable local variations in the association between dental utilization and dental workforce availability. In the multivariate GWR models, 8.5% (t-statistics >1.96) and 13.45% (t-statistics >1.96) of counties showed positive and statistically significant relationships between the dental services utilization and workforce availability of dentists and dental hygienists, respectively. Conclusions Dental workforce availability was associated with dental services utilization in the Appalachian region; however, this association was not statistically significant in all counties. The findings suggest that program and policy efforts to improve dental services utilization need to focus on factors other than increasing the dental workforce availability for many counties in Appalachia. PMID:27957773

Worldwide audit of blood transfusion practice in critically ill patients.

PubMed

Vincent, Jean-Louis; Jaschinski, Ulrich; Wittebole, Xavier; Lefrant, Jean-Yves; Jakob, Stephan M; Almekhlafi, Ghaleb A; Pellis, Tommaso; Tripathy, Swagata; Rubatto Birri, Paolo N; Sakr, Yasser

2018-04-19

The aim was to describe transfusion practice in critically ill patients at an international level and evaluate the effects of red blood cell (RBC) transfusion on outcomes in these patients. This was a pre-planned sub-study of the Intensive Care Over Nations audit, which involved 730 ICUs in 84 countries and included all adult patients admitted between 8 May and 18 May 2012, except admissions for routine postoperative surveillance. ICU and hospital outcomes were recorded. Among the 10,069 patients included in the audit, data related to transfusion had been completed for 9553 (mean age 60 ± 18 years, 60% male); 2511 (26.3%) of these had received a transfusion, with considerable variation among geographic regions. The mean lowest hemoglobin on the day of transfusion was 8.3 ± 1.7 g/dL, but varied from 7.8 ± 1.4 g/dL in the Middle East to 8.9 ± 1.9 g/dL in Eastern Europe. Hospital mortality rates were higher in transfused than in non-transfused patients (30.0% vs. 19.6%, p < 0.001) and increased with increasing numbers of transfused units. In an extended Cox proportional hazard analysis, the relative risk of in-hospital death was slightly lower after transfusion in the whole cohort (hazard ratio 0.98, confidence interval 0.96-1.00, p = 0.048). There was a stepwise decrease in the hazard ratio for mortality after transfusion with increasing admission severity scores. More than one fourth of critically ill patients are transfused during their ICU stay, with considerable variations in transfusion practice among geographic regions. After adjustment for confounders, RBC transfusions were associated with a slightly lower relative risk of in-hospital death, especially in the most severely ill patients, highlighting the importance of taking the severity of illness into account when making transfusion decisions.

Geographic variations in the cost of spine surgery.

PubMed

Goz, Vadim; Rane, Ajinkya; Abtahi, Amir M; Lawrence, Brandon D; Brodke, Darrel S; Spiker, William Ryan

2015-09-01

Retrospective review. To define the geographic variation in costs of anterior cervical discectomy and fusion (ACDF) and posterolateral fusion (PLF). ACDF and lumbar PLF are common procedures that are used in the treatment of spinal pathologies. To optimize value, both the benefits and costs of an intervention must be quantified. Data on costs are scarce in comparison with data on total charges. This study aims at defining the costs of ACDF and PLF and describing the geographic variation within the United States. Medicare Provider Utilization and Payment data were used to investigate the costs associated with ACDF, PLF, and total knee arthroplasty (TKA). Average total costs of the procedures were compared by state and geographic region. Combined professional and facility costs for a single-level ACDF had a national mean of $13,899. Total costs for a single-level PLF had a mean of $25,858. Total costs for a primary TKA had a national mean of $13,039. The cost increased to an average of $22,138 for TKA with major comorbidities. Analysis of geographic trends showed statistically significant differences in total costs of PLF, TKA, and TKA, with major complications or comorbidities between geographic regions (P < 0.01 for all). Three of the 4 procedures (PLF, TKA, and TKA with major complications or comorbidities) showed statistically significant variation in cost between geographic regions. The Midwest provided the lowest cost for all procedures. Similar geographic trends in the cost of spinal fusions and TKAs suggest that these trends may not be limited to spine-related procedures. Surgical costs were found to correlate with cost of living but were not associated with the population of the state. These data shed light on the actual cost of common surgical procedures throughout the United States and will allow further progress toward the development of cost-effective, value-driven care. 3.

Assessment of Geographic and Host-Associated Population Variations of the Carob Moth, Ectomyelois ceratoniae, on Pomegranate, Fig, Pistachio and Walnut, Using AFLP Markers

PubMed Central

Mozaffarian, Fariba; Mardi, Mohsen; Sarafrazi, Alimorad; Nouri Ganbalani, Gadir

2008-01-01

The carob moth, Ectomyelois ceratoniae (Zeller 1839) (Lepidoptera: Pyralidae) is the most important pest of pomegranate, Punica granatum L. (Myrtales: Ponicaceae), in Iran. In this study, 6 amplified fragment length polymorphism primer combinations were used to survey the genetic structure of the geographic and putative host-associated populations of this pest in Iran. An AMOVA was performed on test populations. Pairwise differences, Mantel test, multidimensional analysis, cluster analysis and migration rate were calculated for 5 geographic populations of E. ceratoniae sharing the same host, pomegranate. In another part of the study, 3 comparisons were performed on pairwise populations that were collected on different hosts (pomegranate, fig, pistachio and walnut) in same geographic regions. The results showed high within population variation (85.51% of total variation), however geographic populations differed significantly. The Mantel test did not show correlations between genetic and geographic distances. The probable factors that affect genetic distances are discussed. Multidimensional scaling analysis, migration rate and cluster analysis on geographic populations showed that the Arsanjan population was the most different from the others while the Saveh population was more similar to the Sabzevar population. The comparisons didn't show any host fidelity in test populations. It seems that the ability of E. ceratoniae to broaden its host range with no fidelity to hosts can decrease the efficiency of common control methods that are used on pomegranate. The results of this study suggest that in spite of the effects of geographic barriers, high within-population genetic variation, migration rate and gene flow can provide the opportunity for emerging new phenotypes or behaviors in pest populations, such as broadening host range, changing egg lying places, or changing over-wintering sites to adapt to difficult conditions such as those caused by intensive control methods. PMID:20345296

Geographic Variations in Cardiovascular Disease Mortality Among Asian American Subgroups, 2003-2011.

PubMed

Pu, Jia; Hastings, Katherine G; Boothroyd, Derek; Jose, Powell O; Chung, Sukyung; Shah, Janki B; Cullen, Mark R; Palaniappan, Latha P; Rehkopf, David H

2017-07-12

There are well-documented geographical differences in cardiovascular disease (CVD) mortality for non-Hispanic whites. However, it remains unknown whether similar geographical variation in CVD mortality exists for Asian American subgroups. This study aims to examine geographical differences in CVD mortality among Asian American subgroups living in the United States and whether they are consistent with geographical differences observed among non-Hispanic whites. Using US death records from 2003 to 2011 (n=3 897 040 CVD deaths), age-adjusted CVD mortality rates per 100 000 population and age-adjusted mortality rate ratios were calculated for the 6 largest Asian American subgroups (Asian Indian, Chinese, Filipino, Japanese, Korean, and Vietnamese) and compared with non-Hispanic whites. There were consistently lower mortality rates for all Asian American subgroups compared with non-Hispanic whites across divisions for CVD mortality and ischemic heart disease mortality. However, cerebrovascular disease mortality demonstrated substantial geographical differences by Asian American subgroup. There were a number of regional divisions where certain Asian American subgroups (Filipino and Japanese men, Korean and Vietnamese men and women) possessed no mortality advantage compared with non-Hispanic whites. The most striking geographical variation was with Filipino men (age-adjusted mortality rate ratio=1.18; 95% CI, 1.14-1.24) and Japanese men (age-adjusted mortality rate ratio=1.05; 95% CI: 1.00-1.11) in the Pacific division who had significantly higher cerebrovascular mortality than non-Hispanic whites. There was substantial geographical variation in Asian American subgroup mortality for cerebrovascular disease when compared with non-Hispanic whites. It deserves increased attention to prioritize prevention and treatment in the Pacific division where approximately 80% of Filipinos CVD deaths and 90% of Japanese CVD deaths occur in the United States. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Geographical distribution of human Schistosoma japonicum infection in The Philippines: tools to support disease control and further elimination

PubMed Central

Magalhães, Ricardo J Soares; Salamat, Maria Sonia; Leonardo, Lydia; Gray, Darren J; Carabin, Hélène; Halton, Kate; McManus, Donald P; Williams, Gail M; Rivera, Pilarita; Saniel, Ofelia; Hernandez, Leda; Yakob, Laith; McGarvey, Stephen; Clements, Archie

2015-01-01

Schistosoma japonicum infection is believed to be endemic in 28 of the 80 provinces of The Philippines and the most recent data on schistosomiasis prevalence have shown considerable variability between provinces. In order to increase the efficient allocation of parasitic disease control resources in the country, we aimed to describe the small-scale spatial variation in S. japonicum prevalence across The Philippines, quantify the role of the physical environment in driving the spatial variation of S. japonicum, and develop a predictive risk map of S. japonicum infection. Data on S. japonicum infection from 35,754 individuals across the country were geolocated at the barangay level and included in the analysis. The analysis was then stratified geographically for the regions of Luzon, the Visayas and Mindanao. Zero-inflated binomial Bayesian geostatistical models of S. japonicum prevalence were developed and diagnostic uncertainty was incorporated. Results of the analysis show that in the three regions, males and individuals aged ≥ 20 years had significantly higher prevalence of S. japonicum compared with females and children < 5 years. The role of the environmental variables differed between regions of The Philippines. Schistosoma japonicum infection was widespread in the Visayas whereas it was much more focal in Luzon and Mindanao. This analysis revealed significant spatial variation in the prevalence of S. japonicum infection in The Philippines. This suggests that a spatially targeted approach to schistosomiasis interventions, including mass drug administration, is warranted. When financially possible, additional schistosomiasis surveys should be prioritized for areas identified to be at high risk but which were under-represented in our dataset. PMID:25128879

Multi-approaches analysis reveals local adaptation in the emmer wheat (Triticum dicoccoides) at macro- but not micro-geographical scale.

PubMed

Volis, Sergei; Ormanbekova, Danara; Yermekbayev, Kanat; Song, Minshu; Shulgina, Irina

2015-01-01

Detecting local adaptation and its spatial scale is one of the most important questions of evolutionary biology. However, recognition of the effect of local selection can be challenging when there is considerable environmental variation across the distance at the whole species range. We analyzed patterns of local adaptation in emmer wheat, Triticum dicoccoides, at two spatial scales, small (inter-population distance less than one km) and large (inter-population distance more than 50 km) using several approaches. Plants originating from four distinct habitats at two geographic scales (cold edge, arid edge and two topographically dissimilar core locations) were reciprocally transplanted and their success over time was measured as 1) lifetime fitness in a year of planting, and 2) population growth four years after planting. In addition, we analyzed molecular (SSR) and quantitative trait variation and calculated the QST/FST ratio. No home advantage was detected at the small spatial scale. At the large spatial scale, home advantage was detected for the core population and the cold edge population in the year of introduction via measuring life-time plant performance. However, superior performance of the arid edge population in its own environment was evident only after several generations via measuring experimental population growth rate through genotyping with SSRs allowing counting the number of plants and seeds per introduced genotype per site. These results highlight the importance of multi-generation surveys of population growth rate in local adaptation testing. Despite predominant self-fertilization of T. dicoccoides and the associated high degree of structuring of genetic variation, the results of the QST - FST comparison were in general agreement with the pattern of local adaptation at the two spatial scales detected by reciprocal transplanting.

Geographic origin is not supported by the genetic variability found in a large living collection of Jatropha curcas with accessions from three continents.

PubMed

Maghuly, Fatemeh; Jankowicz-Cieslak, Joanna; Pabinger, Stephan; Till, Bradley J; Laimer, Margit

2015-04-01

Increasing economic interest in Jatropha curcas requires a major research focus on the genetic background and geographic origin of this non-edible biofuel crop. To determine the worldwide genetic structure of this species, amplified fragment length polymorphisms, inter simple sequence repeats, and novel single nucleotide polymorphisms (SNPs) were employed for a large collection of 907 J. curcas accessions and related species (RS) from three continents, 15 countries and 53 regions. PCoA, phenogram, and cophenetic analyses separated RS from two J. curcas groups. Accessions from Mexico, Bolivia, Paraguay, Kenya, and Ethiopia with unknown origins were found in both groups. In general, there was a considerable overlap between individuals from different regions and countries. The Bayesian approach using STRUCTURE demonstrated two groups with a low genetic variation. Analysis of molecular varience revealed significant variation among individuals within populations. SNPs found by in silico analyses of Δ12 fatty acid desaturase indicated possible changes in gene expression and thus in fatty acid profiles. SNP variation was higher in the curcin gene compared to genes involved in oil production. Novel SNPs allowed separating toxic, non-toxic, and Mexican accessions. The present study confirms that human activities had a major influence on the genetic diversity of J. curcas, not only because of domestication, but also because of biased selection. © 2015 The Authors. Biotechnology Journal published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Geographical distribution of human Schistosoma japonicum infection in The Philippines: tools to support disease control and further elimination.

PubMed

Soares Magalhães, Ricardo J; Salamat, Maria Sonia; Leonardo, Lydia; Gray, Darren J; Carabin, Hélène; Halton, Kate; McManus, Donald P; Williams, Gail M; Rivera, Pilarita; Saniel, Ofelia; Hernandez, Leda; Yakob, Laith; McGarvey, Stephen; Clements, Archie

2014-11-01

Schistosoma japonicum infection is believed to be endemic in 28 of the 80 provinces of The Philippines and the most recent data on schistosomiasis prevalence have shown considerable variability between provinces. In order to increase the efficient allocation of parasitic disease control resources in the country, we aimed to describe the small-scale spatial variation in S. japonicum prevalence across The Philippines, quantify the role of the physical environment in driving the spatial variation of S. japonicum, and develop a predictive risk map of S. japonicum infection. Data on S. japonicum infection from 35,754 individuals across the country were geo-located at the barangay level and included in the analysis. The analysis was then stratified geographically for the regions of Luzon, the Visayas and Mindanao. Zero-inflated binomial Bayesian geostatistical models of S. japonicum prevalence were developed and diagnostic uncertainty was incorporated. Results of the analysis show that in the three regions, males and individuals aged ⩾20years had significantly higher prevalence of S. japonicum compared with females and children <5years. The role of the environmental variables differed between regions of The Philippines. Schistosoma japonicum infection was widespread in the Visayas whereas it was much more focal in Luzon and Mindanao. This analysis revealed significant spatial variation in the prevalence of S. japonicum infection in The Philippines. This suggests that a spatially targeted approach to schistosomiasis interventions, including mass drug administration, is warranted. When financially possible, additional schistosomiasis surveys should be prioritised for areas identified to be at high risk but which were under-represented in our dataset. Copyright © 2014 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

A hierarchical model for regional analysis of population change using Christmas Bird Count data, with application to the American Black Duck

USGS Publications Warehouse

Link, W.A.; Sauer, J.R.; Niven, D.K.

2006-01-01

Analysis of Christmas Bird Count (CBC) data is complicated by the need to account for variation in effort on counts and to provide summaries over large geographic regions. We describe a hierarchical model for analysis of population change using CBC data that addresses these needs. The effect of effort is modeled parametrically, with parameter values varying among strata as identically distributed random effects. Year and site effects are modeled hierarchically, accommodating large regional variation in number of samples and precision of estimates. The resulting model is complex, but a Bayesian analysis can be conducted using Markov chain Monte Carlo techniques. We analyze CBC data for American Black Ducks (Anas rubripes), a species of considerable management interest that has historically been monitored using winter surveys. Over the interval 1966-2003, Black Duck populations showed distinct regional patterns of population change. The patterns shown by CBC data are similar to those shown by the Midwinter Waterfowl Inventory for the United States.

Assessing the spatiotemporal dynamic of global grassland carbon use efficiency in response to climate change from 2000 to 2013

NASA Astrophysics Data System (ADS)

Yang, Yue; Wang, Zhaoqi; Li, Jianlong; Gang, Chencheng; Zhang, Yanzhen; Odeh, Inakwu; Qi, Jiaguo

2017-05-01

The carbon use efficiency (CUE) of grassland, a ratio of net primary production (NPP) to gross primary productivity (GPP), is an important index representing the capacity of plants to transfer carbon from the atmosphere to terrestrial biomass. In this study, we used the Moderate Resolution Imaging Spectroradiometer (MODIS) data to calculate the global grassland CUE, and explore the spatiotemporal dynamic of global grassland CUE from 2000 to 2013 to discuss the response to climate variations. The results showed that the average annual CUE of different grassland types follows an order of: open shrublands > non-woody grasslands > closed shrublands > woody savannas > savannas. The higher grassland CUE mainly occurred in the regions with cold and dry climate. By contrast, the regions with the lower grassland CUE were mostly in warm and wet environments. Moreover, the CUE exhibited a globally positive correlation with precipitation and a negative correlation with temperature. Therefore, the grassland CUE has considerable spatial variation associated with grassland type, geographical location and climate change.

Museum genomics: low-cost and high-accuracy genetic data from historical specimens.

PubMed

Rowe, Kevin C; Singhal, Sonal; Macmanes, Matthew D; Ayroles, Julien F; Morelli, Toni Lyn; Rubidge, Emily M; Bi, Ke; Moritz, Craig C

2011-11-01

Natural history collections are unparalleled repositories of geographical and temporal variation in faunal conditions. Molecular studies offer an opportunity to uncover much of this variation; however, genetic studies of historical museum specimens typically rely on extracting highly degraded and chemically modified DNA samples from skins, skulls or other dried samples. Despite this limitation, obtaining short fragments of DNA sequences using traditional PCR amplification of DNA has been the primary method for genetic study of historical specimens. Few laboratories have succeeded in obtaining genome-scale sequences from historical specimens and then only with considerable effort and cost. Here, we describe a low-cost approach using high-throughput next-generation sequencing to obtain reliable genome-scale sequence data from a traditionally preserved mammal skin and skull using a simple extraction protocol. We show that single-nucleotide polymorphisms (SNPs) from the genome sequences obtained independently from the skin and from the skull are highly repeatable compared to a reference genome. © 2011 Blackwell Publishing Ltd.

Global variation in CYP2C8–CYP2C9 functional haplotypes

PubMed Central

Speed, William C; Kang, Soonmo Peter; Tuck, David P; Harris, Lyndsay N; Kidd, Kenneth K

2009-01-01

We have studied the global frequency distributions of 10 single nucleotide polymorphisms (SNPs) across 132 kb of CYP2C8 and CYP2C9 in ∼2500 individuals representing 45 populations. Five of the SNPs were in noncoding sequences; the other five involved the more common missense variants (four in CYP2C8, one in CYP2C9) that change amino acids in the gene products. One haplotype containing two CYP2C8 coding variants and one CYP2C9 coding variant reaches an average frequency of 10% in Europe; a set of haplotypes with a different CYP2C8 coding variant reaches 17% in Africa. In both cases these haplotypes are found in other regions of the world at <1%. This considerable geographic variation in haplotype frequencies impacts the interpretation of CYP2C8/CYP2C9 association studies, and has pharmacogenomic implications for drug interactions. PMID:19381162

A Quantitative Comparison of the Similarity between Genes and Geography in Worldwide Human Populations

PubMed Central

Wang, Chaolong; Zöllner, Sebastian; Rosenberg, Noah A.

2012-01-01

Multivariate statistical techniques such as principal components analysis (PCA) and multidimensional scaling (MDS) have been widely used to summarize the structure of human genetic variation, often in easily visualized two-dimensional maps. Many recent studies have reported similarity between geographic maps of population locations and MDS or PCA maps of genetic variation inferred from single-nucleotide polymorphisms (SNPs). However, this similarity has been evident primarily in a qualitative sense; and, because different multivariate techniques and marker sets have been used in different studies, it has not been possible to formally compare genetic variation datasets in terms of their levels of similarity with geography. In this study, using genome-wide SNP data from 128 populations worldwide, we perform a systematic analysis to quantitatively evaluate the similarity of genes and geography in different geographic regions. For each of a series of regions, we apply a Procrustes analysis approach to find an optimal transformation that maximizes the similarity between PCA maps of genetic variation and geographic maps of population locations. We consider examples in Europe, Sub-Saharan Africa, Asia, East Asia, and Central/South Asia, as well as in a worldwide sample, finding that significant similarity between genes and geography exists in general at different geographic levels. The similarity is highest in our examples for Asia and, once highly distinctive populations have been removed, Sub-Saharan Africa. Our results provide a quantitative assessment of the geographic structure of human genetic variation worldwide, supporting the view that geography plays a strong role in giving rise to human population structure. PMID:22927824

A quantitative comparison of the similarity between genes and geography in worldwide human populations.

PubMed

Wang, Chaolong; Zöllner, Sebastian; Rosenberg, Noah A

2012-08-01

Multivariate statistical techniques such as principal components analysis (PCA) and multidimensional scaling (MDS) have been widely used to summarize the structure of human genetic variation, often in easily visualized two-dimensional maps. Many recent studies have reported similarity between geographic maps of population locations and MDS or PCA maps of genetic variation inferred from single-nucleotide polymorphisms (SNPs). However, this similarity has been evident primarily in a qualitative sense; and, because different multivariate techniques and marker sets have been used in different studies, it has not been possible to formally compare genetic variation datasets in terms of their levels of similarity with geography. In this study, using genome-wide SNP data from 128 populations worldwide, we perform a systematic analysis to quantitatively evaluate the similarity of genes and geography in different geographic regions. For each of a series of regions, we apply a Procrustes analysis approach to find an optimal transformation that maximizes the similarity between PCA maps of genetic variation and geographic maps of population locations. We consider examples in Europe, Sub-Saharan Africa, Asia, East Asia, and Central/South Asia, as well as in a worldwide sample, finding that significant similarity between genes and geography exists in general at different geographic levels. The similarity is highest in our examples for Asia and, once highly distinctive populations have been removed, Sub-Saharan Africa. Our results provide a quantitative assessment of the geographic structure of human genetic variation worldwide, supporting the view that geography plays a strong role in giving rise to human population structure.

Geographic variation in shortleaf pine (Pinus echinata Mill.) - cortical monoterpenes

Treesearch

R.C. Schmidtling; J.H. Myszewski; C.E. McDaniel

2005-01-01

Cortical monoterpenes were assayed in bud tissue from 16 Southwide Southern Pine Seed Source Study (SSPSS) sources and from 6 seed orchard sources fiom across the natural range of the species, to examine geogaphic variation in shortleaf pine. Spruce pine and pond pine were also sampled. The results show geographic differences in all of the major terpenes. There was no...

Geographic variation in forest composition and precipitation predict the synchrony of forest insect outbreaks

Treesearch

Kyle J. Haynes; Andrew M. Liebhold; Ottar N. Bjørnstad; Andrew J. Allstadt; Randall S. Morin

2018-01-01

Evaluating the causes of spatial synchrony in population dynamics in nature is notoriously difficult due to a lack of data and appropriate statistical methods. Here, we use a recently developed method, a multivariate extension of the local indicators of spatial autocorrelation statistic, to map geographic variation in the synchrony of gypsy moth outbreaks. Regression...

Conservation genetics and geographic patterns of genetic variation of the vulnerable officinal herb Fritillaria walujewii (Liliaceae)

Treesearch

Zhihao Su; Borong Pan; Stewart C. Sanderson; Xiaojun Shi; Xiaolong Jiang

2015-01-01

The Chinese herb Fritillaria walujewii Regel is an important officinal species that is vulnerable because of over-harvesting. Here, we examined the geographic pattern of genetic variation across the species entire range, to study its evolution process and give implication needed for the conservation. Nine haplotypes were detected on the basis of three chloroplast...

Geographic patterns of variation in biomass production of California blue oak seedlings as a response to water availability

Treesearch

Susan Kloss; Joe R. McBride

2002-01-01

This study characterized the distribution of geographic variation in water relations traits for six populations of California blue oak along a precipitation gradient (two each from high, medium and low precipitation environments). Acorns were collected from each population, germinated and the resulting seedlings were experimentally treated with three different watering...

Geographic variation in survival and migratory tendency among North American Common Mergansers

USGS Publications Warehouse

Pearce, J.M.; Reed, J.A.; Flint, Paul L.

2005-01-01

Movement ecology and demographic parameters for the Common Merganser (Mergus merganser americanus) in North America are poorly known. We used band-recovery data from five locations across North America spanning the years 1938-1998 to examine migratory patterns and estimate survival rates. We examined competing time-invariant, age-graduated models with program MARK to study sources of variation in survival and reporting probability. We considered age, sex, geographic location, and the use of nasal saddles on hatching year birds at one location as possible sources of variation. Year-of-banding was included as a covariate in a post-hoc analysis. We found that migratory tendency, defined as the average distance between banding and recovery locations, varied geographically. Similarly, all models accounting for the majority of variation in recovery and survival probabilities included location of banding. Models that included age and sex received less support, but we lacked sufficient data to adequately assess these parameters. Model-averaged estimates of annual survival ranged from 0.21 in Michigan to 0.82 in Oklahoma. Heterogeneity in migration tendency and survival suggests that demographic patterns may vary across geographic scales, with implications for the population dynamics of this species.

Population structure and cultural geography of a folktale in Europe

PubMed Central

Ross, Robert M.; Greenhill, Simon J.; Atkinson, Quentin D.

2013-01-01

Despite a burgeoning science of cultural evolution, relatively little work has focused on the population structure of human cultural variation. By contrast, studies in human population genetics use a suite of tools to quantify and analyse spatial and temporal patterns of genetic variation within and between populations. Human genetic diversity can be explained largely as a result of migration and drift giving rise to gradual genetic clines, together with some discontinuities arising from geographical and cultural barriers to gene flow. Here, we adapt theory and methods from population genetics to quantify the influence of geography and ethnolinguistic boundaries on the distribution of 700 variants of a folktale in 31 European ethnolinguistic populations. We find that geographical distance and ethnolinguistic affiliation exert significant independent effects on folktale diversity and that variation between populations supports a clustering concordant with European geography. This pattern of geographical clines and clusters parallels the pattern of human genetic diversity in Europe, although the effects of geographical distance and ethnolinguistic boundaries are stronger for folktales than genes. Our findings highlight the importance of geography and population boundaries in models of human cultural variation and point to key similarities and differences between evolutionary processes operating on human genes and culture. PMID:23390109

Exploring Geographic Variation of Mental Health Risk and Service Utilization of Doctors and Hospitals in Toronto: A Shared Component Spatial Modeling Approach

PubMed Central

Perlman, Christopher

2018-01-01

Mental Health has been known to vary geographically. Different rates of utilization of mental health services in local areas reflect geographic variation of mental health and complexity of health care. Variations and inequalities in how the health care system addresses risks are two critical issues for addressing population mental health. This study examines these issues by analyzing the utilization of mental health services in Toronto at the neighbourhood level. We adopted a shared component spatial modeling approach that allows simultaneous analysis of two main health service utilizations: doctor visits and hospitalizations related to mental health conditions. Our results reflect a geographic variation of both types of mental health service utilization across neighbourhoods in Toronto. We identified hot and cold spots of mental health risks that are common to both or specific to only one type of health service utilization. Based on the evidence found, we discuss intervention strategies, focusing on the hotspots and provision of health services about doctors and hospitals, to improve mental health for the neighbourhoods. Limitations of the study and further research directions are also discussed. PMID:29587426

A multilevel model for cardiovascular disease prevalence in the US and its application to micro area prevalence estimates.

PubMed

Congdon, Peter

2009-01-30

Estimates of disease prevalence for small areas are increasingly required for the allocation of health funds according to local need. Both individual level and geographic risk factors are likely to be relevant to explaining prevalence variations, and in turn relevant to the procedure for small area prevalence estimation. Prevalence estimates are of particular importance for major chronic illnesses such as cardiovascular disease. A multilevel prevalence model for cardiovascular outcomes is proposed that incorporates both survey information on patient risk factors and the effects of geographic location. The model is applied to derive micro area prevalence estimates, specifically estimates of cardiovascular disease for Zip Code Tabulation Areas in the USA. The model incorporates prevalence differentials by age, sex, ethnicity and educational attainment from the 2005 Behavioral Risk Factor Surveillance System survey. Influences of geographic context are modelled at both county and state level, with the county effects relating to poverty and urbanity. State level influences are modelled using a random effects approach that allows both for spatial correlation and spatial isolates. To assess the importance of geographic variables, three types of model are compared: a model with person level variables only; a model with geographic effects that do not interact with person attributes; and a full model, allowing for state level random effects that differ by ethnicity. There is clear evidence that geographic effects improve statistical fit. Geographic variations in disease prevalence partly reflect the demographic composition of area populations. However, prevalence variations may also show distinct geographic 'contextual' effects. The present study demonstrates by formal modelling methods that improved explanation is obtained by allowing for distinct geographic effects (for counties and states) and for interaction between geographic and person variables. Thus an appropriate methodology to estimate prevalence at small area level should include geographic effects as well as person level demographic variables.

A multilevel model for cardiovascular disease prevalence in the US and its application to micro area prevalence estimates

PubMed Central

Congdon, Peter

2009-01-01

Background Estimates of disease prevalence for small areas are increasingly required for the allocation of health funds according to local need. Both individual level and geographic risk factors are likely to be relevant to explaining prevalence variations, and in turn relevant to the procedure for small area prevalence estimation. Prevalence estimates are of particular importance for major chronic illnesses such as cardiovascular disease. Methods A multilevel prevalence model for cardiovascular outcomes is proposed that incorporates both survey information on patient risk factors and the effects of geographic location. The model is applied to derive micro area prevalence estimates, specifically estimates of cardiovascular disease for Zip Code Tabulation Areas in the USA. The model incorporates prevalence differentials by age, sex, ethnicity and educational attainment from the 2005 Behavioral Risk Factor Surveillance System survey. Influences of geographic context are modelled at both county and state level, with the county effects relating to poverty and urbanity. State level influences are modelled using a random effects approach that allows both for spatial correlation and spatial isolates. Results To assess the importance of geographic variables, three types of model are compared: a model with person level variables only; a model with geographic effects that do not interact with person attributes; and a full model, allowing for state level random effects that differ by ethnicity. There is clear evidence that geographic effects improve statistical fit. Conclusion Geographic variations in disease prevalence partly reflect the demographic composition of area populations. However, prevalence variations may also show distinct geographic 'contextual' effects. The present study demonstrates by formal modelling methods that improved explanation is obtained by allowing for distinct geographic effects (for counties and states) and for interaction between geographic and person variables. Thus an appropriate methodology to estimate prevalence at small area level should include geographic effects as well as person level demographic variables. PMID:19183458

Geographic variation in the relationship between body mass index and the built environment.

PubMed

Adachi-Mejia, Anna M; Lee, Chanam; Lee, Chunkuen; Carlos, Heather A; Saelens, Brian E; Berke, Ethan M; Doescher, Mark P

2017-07-01

Studies examining associations between weight status and neighborhood built environment (BE) have shown inconsistent results and have generally focused on urban settings. However, many Americans do not live in metropolitan areas and BE impacts may be different outside of metropolitan areas. We sought to examine whether the relationship between body mass index (BMI) and neighborhood BE exists and varies by geographic region across small towns in the United States. We conducted telephone surveys with 2156 adults and geographic information systems data in nine towns located within three geographic regions (Northeast, Texas, Washington) in 2011 and 2012. Multiple regression models examined the relationship between individual BMI and BE measures. Most physical activity variables were significantly associated with lower BMI in all geographic regions. We saw variation across geographic region in the relationship between characteristics of the BE variables and BMI. Some perceived and objectively-measured characteristics of the BE were significantly associated with adult BMI, but significant relationships varied by geographic region. For example, in the Northeast, perceived attractiveness of the neighborhood as a reason for why they chose to live there was associated with lower BMI; in Texas, the perceived presence of a fast food restaurant was negatively associated with BMI; in Washington, perceived presence of trees along the streets was associated with lower BMI. Our findings suggest that regional variation plays a role in the relationship between adult BMI and BE characteristics in small towns. Regardless of geographic location, interventions should encourage utilitarian walking and other forms of physical activity. Copyright © 2017 Elsevier Inc. All rights reserved.

The relationship between female brooding and male nestling provisioning: does climate underlie geographic variation in sex roles?

USGS Publications Warehouse

Yoon, Jongmin; Sofaer, Helen R.; Sillett, T. Scott; Morrison, Scott A.; Ghalambor, Cameron K.

2017-01-01

Comparative studies of populations occupying different environments can provide insights into the ecological conditions affecting differences in parental strategies, including the relative contributions of males and females. Male and female parental strategies reflect the interplay between ecological conditions, the contributions of the social mate, and the needs of offspring. Climate is expected to underlie geographic variation in incubation and brooding behavior, and can thereby affect both the absolute and relative contributions of each sex to other aspects of parental care such as offspring provisioning. However, geographic variation in brooding behavior has received much less attention than variation in incubation attentiveness or provisioning rates. We compared parental behavior during the nestling period in populations of orange-crowned warblers Oreothlypis celata near the northern (64°N) and southern (33°N) boundaries of the breeding range. In Alaska, we found that males were responsible for the majority of food delivery whereas the sexes contributed equally to provisioning in California. Higher male provisioning in Alaska appeared to facilitate a higher proportion of time females spent brooding the nestlings. Surprisingly, differences in brooding between populations could not be explained by variation in ambient temperature, which was similar between populations during the nestling period. While these results represent a single population contrast, they suggest additional hypotheses for the ecological correlates and evolutionary drivers of geographic variation in brooding behavior, and the factors that shape the contributions of each sex.

Country and regional variations in purchase prices for essential cancer medications.

PubMed

Cuomo, Raphael E; Seidman, Robert L; Mackey, Tim K

2017-08-24

Accessibility to essential cancer medications in low- and middle-income countries is threatened by insufficient availability and affordability. The objective of this study is to characterize variation in transactional prices for essential cancer medications across geographies, medication type, and time. Drug purchase prices for 19 national and international buyers (representing 29 total countries) between 2010 and 2014 were obtained from Management Sciences for Health. Median values for drug pricing were computed, to address outliers in the data. For comparing purchase prices across geographic units, medications, and over time; Mann-Whitney U tests were used to compare two groups, Kruskal Wallis H tests were used to compare more than two groups, and linear regression was used to compare across continuous independent variables. During the five-year data period examined, the median price paid for a package of essential cancer medication was $12.63. No significant differences in prices were found based on country-level wealth, country-level disease burden, drug formulation, or year when medication was purchased. Statistical tests found significant differences in prices paid across countries, regions, individual medications, and medication categories. Specifically, countries in the Africa region appeared to pay more for a package of essential cancer medication than countries in the Latin America region, and cancer medications tended to be more expensive than anti-infective medications and cardiovascular medications. Though preliminary, our study found evidence of variation in prices paid by health systems to acquire essential cancer medications. Primarily, variations in pricing based on geographic location and cancer medication type (including when comparing to essential medicines that treat cardiovascular and infectious diseases) indicate that these factors may impact availability, affordability and access to essential cancer drugs. These factors should be taken into consideration when countries assess formulary decisions, negotiate drug procurement terms, and when formulating health and cancer policy.

Geographic Clustering of Cardiometabolic Risk Factors in Metropolitan Centres in France and Australia

PubMed Central

Paquet, Catherine; Chaix, Basile; Howard, Natasha J.; Coffee, Neil T.; Adams, Robert J.; Taylor, Anne W.; Thomas, Frédérique; Daniel, Mark

2016-01-01

Understanding how health outcomes are spatially distributed represents a first step in investigating the scale and nature of environmental influences on health and has important implications for statistical power and analytic efficiency. Using Australian and French cohort data, this study aimed to describe and compare the extent of geographic variation, and the implications for analytic efficiency, across geographic units, countries and a range of cardiometabolic parameters (Body Mass Index (BMI) waist circumference, blood pressure, resting heart rate, triglycerides, cholesterol, glucose, HbA1c). Geographic clustering was assessed using Intra-Class Correlation (ICC) coefficients in biomedical cohorts from Adelaide (Australia, n = 3893) and Paris (France, n = 6430) for eight geographic administrative units. The median ICC was 0.01 suggesting 1% of risk factor variance attributable to variation between geographic units. Clustering differed by cardiometabolic parameters, administrative units and countries and was greatest for BMI and resting heart rate in the French sample, HbA1c in the Australian sample, and for smaller geographic units. Analytic inefficiency due to clustering was greatest for geographic units in which participants were nested in fewer, larger geographic units. Differences observed in geographic clustering across risk factors have implications for choice of geographic unit in sampling and analysis, and highlight potential cross-country differences in the distribution, or role, of environmental features related to cardiometabolic health. PMID:27213423

Geographic variation in the aetiology, epidemiology and microbiology of bronchiectasis.

PubMed

Chandrasekaran, Ravishankar; Mac Aogáin, Micheál; Chalmers, James D; Elborn, Stuart J; Chotirmall, Sanjay H

2018-05-22

Bronchiectasis is a disease associated with chronic progressive and irreversible dilatation of the bronchi and is characterised by chronic infection and associated inflammation. The prevalence of bronchiectasis is age-related and there is some geographical variation in incidence, prevalence and clinical features. Most bronchiectasis is reported to be idiopathic however post-infectious aetiologies dominate across Asia especially secondary to tuberculosis. Most focus to date has been on the study of airway bacteria, both as colonisers and causes of exacerbations. Modern molecular technologies including next generation sequencing (NGS) have become invaluable tools to identify microorganisms directly from sputum and which are difficult to culture using traditional agar based methods. These have provided important insight into our understanding of emerging pathogens in the airways of people with bronchiectasis and the geographical differences that occur. The contribution of the lung microbiome, its ethnic variation, and subsequent roles in disease progression and response to therapy across geographic regions warrant further investigation. This review summarises the known geographical differences in the aetiology, epidemiology and microbiology of bronchiectasis. Further, we highlight the opportunities offered by emerging molecular technologies such as -omics to further dissect out important ethnic differences in the prognosis and management of bronchiectasis.

The Geographic Distribution of Genetic Risk as Compared to Social Risk for Chronic Diseases in the United States.

PubMed

Rehkopf, David H; Domingue, Benjamin W; Cullen, Mark R

2016-01-01

There is an association between chronic disease and geography, and there is evidence that the environment plays a critical role in this relationship. Yet at the same time, there is known to be substantial geographic variation by ancestry across the United States. Resulting geographic genetic variation-that is, the extent to which single nucleotide polymorphisms (SNPs) related to chronic disease vary spatially-could thus drive some part of the association between geography and disease. We describe the variation in chronic disease genetic risk by state of birth by taking risk SNPs from genome-wide association study meta-analyses for coronary artery disease, diabetes, and ischemic stroke and creating polygenic risk scores. We compare the amount of variability across state of birth in these polygenic scores to the variability in parental education, own education, earnings, and wealth. Our primary finding is that the polygenic risk scores are only weakly differentially distributed across U.S. states. The magnitude of the differences in geographic distribution is very small in comparison to the distribution of social and economic factors and thus is not likely sufficient to have a meaningful effect on geographic disease differences by U.S. state.

Os zygomaticum bipartitum: frequency distribution in major human populations

PubMed Central

HANIHARA, TSUNEHIKO; ISHIDA, HAJIME; DODO, YUKIO

1998-01-01

The frequency of the Os zygomaticum bipartitum was examined in major human populations around the world. Eastern Asians have a higher frequency of the bipartite zygomatic bone than any other geographical groups. The arctic peoples, Amerindians and the Oceanians, who all may have derived from eastern Asian population stocks, have a considerably low frequency of this trait. The frequency distribution from East/Southeast Asia to Africa and Europe through South/Central/West Asia suggests some clinality for the bipartite zygomatic bone. The second peak in the frequency is seen in Subsaharan Africa. The clinal variation with no identifiable regulation by subsistence patterns and environmental factors suggested a genetic background for the occurrence of the Os zygomaticum bipartitum. PMID:9723981

Reducing variation in decomposition odour profiling using comprehensive two-dimensional gas chromatography.

PubMed

Perrault, Katelynn A; Stefanuto, Pierre-Hugues; Stuart, Barbara H; Rai, Tapan; Focant, Jean-François; Forbes, Shari L

2015-01-01

Challenges in decomposition odour profiling have led to variation in the documented odour profile by different research groups worldwide. Background subtraction and use of controls are important considerations given the variation introduced by decomposition studies conducted in different geographical environments. The collection of volatile organic compounds (VOCs) from soil beneath decomposing remains is challenging due to the high levels of inherent soil VOCs, further confounded by the use of highly sensitive instrumentation. This study presents a method that provides suitable chromatographic resolution for profiling decomposition odour in soil by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry using appropriate controls and field blanks. Logarithmic transformation and t-testing of compounds permitted the generation of a compound list of decomposition VOCs in soil. Principal component analysis demonstrated the improved discrimination between experimental and control soil, verifying the value of the data handling method. Data handling procedures have not been well documented in this field and standardisation would thereby reduce misidentification of VOCs present in the surrounding environment as decomposition byproducts. Uniformity of data handling and instrumental procedures will reduce analytical variation, increasing confidence in the future when investigating the effect of taphonomic variables on the decomposition VOC profile. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Validation of prediction models: examining temporal and geographic stability of baseline risk and estimated covariate effects

PubMed Central

Austin, Peter C.; van Klaveren, David; Vergouwe, Yvonne; Nieboer, Daan; Lee, Douglas S.; Steyerberg, Ewout W.

2018-01-01

Background Stability in baseline risk and estimated predictor effects both geographically and temporally is a desirable property of clinical prediction models. However, this issue has received little attention in the methodological literature. Our objective was to examine methods for assessing temporal and geographic heterogeneity in baseline risk and predictor effects in prediction models. Methods We studied 14,857 patients hospitalized with heart failure at 90 hospitals in Ontario, Canada, in two time periods. We focussed on geographic and temporal variation in baseline risk (intercept) and predictor effects (regression coefficients) of the EFFECT-HF mortality model for predicting 1-year mortality in patients hospitalized for heart failure. We used random effects logistic regression models for the 14,857 patients. Results The baseline risk of mortality displayed moderate geographic variation, with the hospital-specific probability of 1-year mortality for a reference patient lying between 0.168 and 0.290 for 95% of hospitals. Furthermore, the odds of death were 11% lower in the second period than in the first period. However, we found minimal geographic or temporal variation in predictor effects. Among 11 tests of differences in time for predictor variables, only one had a modestly significant P value (0.03). Conclusions This study illustrates how temporal and geographic heterogeneity of prediction models can be assessed in settings with a large sample of patients from a large number of centers at different time periods. PMID:29350215

Exploring natural variation of photosynthetic, primary metabolism and growth parameters in a large panel of Capsicum chinense accessions.

PubMed

Rosado-Souza, Laise; Scossa, Federico; Chaves, Izabel S; Kleessen, Sabrina; Salvador, Luiz F D; Milagre, Jocimar C; Finger, Fernando; Bhering, Leonardo L; Sulpice, Ronan; Araújo, Wagner L; Nikoloski, Zoran; Fernie, Alisdair R; Nunes-Nesi, Adriano

2015-09-01

Collectively, the results presented improve upon the utility of an important genetic resource and attest to a complex genetic basis for differences in both leaf metabolism and fruit morphology between natural populations. Diversity of accessions within the same species provides an alternative method to identify physiological and metabolic traits that have large effects on growth regulation, biomass and fruit production. Here, we investigated physiological and metabolic traits as well as parameters related to plant growth and fruit production of 49 phenotypically diverse pepper accessions of Capsicum chinense grown ex situ under controlled conditions. Although single-trait analysis identified up to seven distinct groups of accessions, working with the whole data set by multivariate analyses allowed the separation of the 49 accessions in three clusters. Using all 23 measured parameters and data from the geographic origin for these accessions, positive correlations between the combined phenotypes and geographic origin were observed, supporting a robust pattern of isolation-by-distance. In addition, we found that fruit set was positively correlated with photosynthesis-related parameters, which, however, do not explain alone the differences in accession susceptibility to fruit abortion. Our results demonstrated that, although the accessions belong to the same species, they exhibit considerable natural intraspecific variation with respect to physiological and metabolic parameters, presenting diverse adaptation mechanisms and being a highly interesting source of information for plant breeders. This study also represents the first study combining photosynthetic, primary metabolism and growth parameters for Capsicum to date.

Cancer mortality in Brazil

PubMed Central

Barbosa, Isabelle R.; de Souza, Dyego L.B.; Bernal, María M.; Costa, Íris do C.C.

2015-01-01

Abstract Cancer is currently in the spotlight due to their heavy responsibility as main cause of death in both developed and developing countries. Analysis of the epidemiological situation is required as a support tool for the planning of public health measures for the most vulnerable groups. We analyzed cancer mortality trends in Brazil and geographic regions in the period 1996 to 2010 and calculate mortality predictions for the period 2011 to 2030. This is an epidemiological, demographic-based study that utilized information from the Mortality Information System on all deaths due to cancer in Brazil. Mortality trends were analyzed by the Joinpoint regression, and Nordpred was utilized for the calculation of predictions. Stability was verified for the female (annual percentage change [APC] = 0.4%) and male (APC = 0.5%) sexes. The North and Northeast regions present significant increasing trends for mortality in both sexes. Until 2030, female mortality trends will not present considerable variations, but there will be a decrease in mortality trends for the male sex. There will be increases in mortality rates until 2030 for the North and Northeast regions, whereas reductions will be verified for the remaining geographic regions. This variation will be explained by the demographic structure of regions until 2030. There are pronounced regional and sex differences in cancer mortality in Brazil, and these discrepancies will continue to increase until the year 2030, when the Northeast region will present the highest cancer mortality rates in Brazil. PMID:25906105

Comparative epigenetic and genetic spatial structure of the perennial herb Helleborus foetidus: Isolation by environment, isolation by distance, and functional trait divergence.

PubMed

Herrera, Carlos M; Medrano, Mónica; Bazaga, Pilar

2017-08-16

Epigenetic variation can play a role in local adaptation; thus, there should be associations among epigenetic variation, environmental variation, and functional trait variation across populations. This study examines these relationships in the perennial herb Helleborus foetidus (Ranunculaceae). Plants from 10 subpopulations were characterized genetically (AFLP, SSR markers), epigenetically (MSAP markers), and phenotypically (20 functional traits). Habitats were characterized using six environmental variables. Isolation-by-distance (IBD) and isolation-by-environment (IBE) patterns of genetic and epigenetic divergence were assessed, as was the comparative explanatory value of geographical and environmental distance as predictors of epigenetic, genetic, and functional differentiation. Subpopulations were differentiated genetically, epigenetically, and phenotypically. Genetic differentiation was best explained by geographical distance, while epigenetic differentiation was best explained by environmental distance. Divergence in functional traits was correlated with environmental and epigenetic distances, but not with geographical and genetic distances. Results are compatible with the hypothesis that epigenetic IBE and functional divergence reflected responses to environmental variation. Spatial analyses simultaneously considering epigenetic, genetic, phenotypic and environmental information provide a useful tool to evaluate the role of environmental features as drivers of natural epigenetic variation between populations. © 2017 Botanical Society of America.

Craniofacial plasticity in ancient Peru.

PubMed

Stone, Jessica H; Chew, Kristen; Ross, Ann H; Verano, John W

2015-01-01

Numerous studies have utilized craniometric data to explore the roles of genetic diversity and environment in human cranial shape variation. Peru is a particularly interesting region to examine cranial variation due to the wide variety of high and low altitude ecological zones, which in combination with rugged terrain have created isolated populations with vastly different physiological adaptations. This study examines seven samples from throughout Peru in an effort to understand the contributions of environmental adaptation and genetic relatedness to craniofacial variation at a regional scale. Morphological variation was investigated using a canonical discriminant analysis and Mahalanobis D(2) analysis. Results indicate that all groups are significantly different from one another with the closest relationship between Yauyos and Jahuay, two sites that are located geographically close in central Peru but in very different ecozones. The relationship between latitude/longitude and face shape was also examined with a spatial autocorrelation analysis (Moran's I) using ArcMap and show that there is significant spatial patterning for facial measures and geographic location suggesting that there is an association between biological variation and geographic location.

Patterns of population subdivision, gene flow and genetic variability in the African wild dog (Lycaon pictus).

PubMed

Girman, D J; Vilà, C; Geffen, E; Creel, S; Mills, M G; McNutt, J W; Ginsberg, J; Kat, P W; Mamiya, K H; Wayne, R K

2001-07-01

African wild dogs are large, highly mobile carnivores that are known to disperse over considerable distances and are rare throughout much of their geographical range. Consequently, genetic variation within and differentiation between geographically separated populations is predicted to be minimal. We determined the genetic diversity of mitochondrial DNA (mtDNA) control region sequences and microsatellite loci in seven populations of African wild dogs. Analysis of mtDNA nucleotide diversity suggests that, historically, wild dog populations have been small relative to other large carnivores. However, population declines due to recent habitat loss have not caused a dramatic reduction in genetic diversity. We found one historical and eight recent mtDNA genotypes in 280 individuals that defined two highly divergent clades. In contrast to a previous, more limited, mtDNA analysis, sequences from these clades are not geographically restricted to eastern or southern African populations. Rather, we found a large admixture zone spanning populations from Botswana, Zimbabwe and south-eastern Tanzania. Mitochondrial and microsatellite differentiation between populations was significant and unique mtDNA genotypes and alleles characterized the populations. However, gene flow estimates (Nm) based on microsatellite data were generally greater than one migrant per generation. In contrast, gene flow estimates based on the mtDNA control region were lower than expected given differences in the mode of inheritance of mitochondrial and nuclear markers which suggests a male bias in long-distance dispersal.

Habitat heterogeneity of hadal trenches: Considerations and implications for future studies

NASA Astrophysics Data System (ADS)

Stewart, Heather A.; Jamieson, Alan J.

2018-02-01

The hadal zone largely comprises a series of subduction trenches that do not form part of the continental shelf-slope rise to abyssal plain continuum. Instead they form geographically isolated clusters of deep-sea (6000-11,000 m water depth) environments. There is a growing realization in hadal science that ecological patterns and processes are not driven solely by responses to hydrostatic pressure, with comparable levels of habitat heterogeneity as observed in other marine biozones. Furthermore, this heterogeneity can be expressed at multiple scales from inter-trench levels (degrees of geographical isolation, and biochemical province), to intra-trench levels (variation between trench flanks and axis), topographical features within the trench interior (sedimentary basins, ridges, escarpments, 'deeps', seamounts) to the substrate of the trench floor (seabed-sediment composition, mass movement deposits, bedrock outcrop). Using best available bathymetry data combined with the largest lander-derived imaging dataset that spans the full depth range of three hadal trenches (including adjacent slopes); the Mariana, Kermadec and New Hebrides trenches, the topographic variability, fine-scale habitat heterogeneity and distribution of seabed sediments of these three trenches have been assessed for the first time. As well as serving as the first descriptive study of habitat heterogeneity at hadal depths, this study also provides guidance for future hadal sampling campaigns taking into account geographic isolation, total trench particulate organic matter flux, maximum water depth and area.

Plant Chemistry and Local Adaptation of a Specialized Folivore

PubMed Central

Laukkanen, Liisa; Leimu, Roosa; Muola, Anne; Lilley, Marianna; Salminen, Juha-Pekka; Mutikainen, Pia

2012-01-01

Local adaptation is central for creating and maintaining spatial variation in plant-herbivore interactions. Short-lived insect herbivores feeding on long-lived plants are likely to adapt to their local host plants, because of their short generation time, poor dispersal, and geographically varying selection due to variation in plant defences. In a reciprocal feeding trial, we investigated the impact of geographic variation in plant secondary chemistry of a long-lived plant, Vincetoxicum hirundinaria, on among-population variation in local adaptation of a specialist leaf-feeding herbivore, Abrostola asclepiadis. The occurrence and degree of local adaptation varied among populations. This variation correlated with qualitative and quantitative differences in plant chemistry among the plant populations. These findings provide insights into the mechanisms driving variation in local adaptation in this specialized plant-herbivore interaction. PMID:22666493

Deciphering the adjustment between environment and life history in annuals: lessons from a geographically-explicit approach in Arabidopsis thaliana.

PubMed

Manzano-Piedras, Esperanza; Marcer, Arnald; Alonso-Blanco, Carlos; Picó, F Xavier

2014-01-01

The role that different life-history traits may have in the process of adaptation caused by divergent selection can be assessed by using extensive collections of geographically-explicit populations. This is because adaptive phenotypic variation shifts gradually across space as a result of the geographic patterns of variation in environmental selective pressures. Hence, large-scale experiments are needed to identify relevant adaptive life-history traits as well as their relationships with putative selective agents. We conducted a field experiment with 279 geo-referenced accessions of the annual plant Arabidopsis thaliana collected across a native region of its distribution range, the Iberian Peninsula. We quantified variation in life-history traits throughout the entire life cycle. We built a geographic information system to generate an environmental data set encompassing climate, vegetation and soil data. We analysed the spatial autocorrelation patterns of environmental variables and life-history traits, as well as the relationship between environmental and phenotypic data. Almost all environmental variables were significantly spatially autocorrelated. By contrast, only two life-history traits, seed weight and flowering time, exhibited significant spatial autocorrelation. Flowering time, and to a lower extent seed weight, were the life-history traits with the highest significant correlation coefficients with environmental factors, in particular with annual mean temperature. In general, individual fitness was higher for accessions with more vigorous seed germination, higher recruitment and later flowering times. Variation in flowering time mediated by temperature appears to be the main life-history trait by which A. thaliana adjusts its life history to the varying Iberian environmental conditions. The use of extensive geographically-explicit data sets obtained from field experiments represents a powerful approach to unravel adaptive patterns of variation. In a context of current global warming, geographically-explicit approaches, evaluating the match between organisms and the environments where they live, may contribute to better assess and predict the consequences of global warming.

Geographic variation in gorilla limb bones.

PubMed

Jabbour, Rebecca S; Pearman, Tessa L

2016-06-01

Gorilla systematics has received increased attention over recent decades from primatologists, conservationists, and paleontologists. Studies of geographic variation in DNA, skulls, and teeth have led to new taxonomic proposals, such as recognition of two gorilla species, Gorilla gorilla (western gorilla) and Gorilla beringei (eastern gorilla). Postcranial differences between mountain gorillas (G. beringei beringei) and western lowland gorillas (G. g. gorilla) have a long history of study, but differences between the limb bones of the eastern and western species have not yet been examined with an emphasis on geographic variation within each species. In addition, proposals for recognition of the Cross River gorilla as Gorilla gorilla diehli and gorillas from Tshiaberimu and Kahuzi as G. b. rex-pymaeorum have not been evaluated in the context of geographic variation in the forelimb and hindlimb skeletons. Forty-three linear measurements were collected from limb bones of 266 adult gorillas representing populations of G. b. beringei, Gorilla beringei graueri, G. g. gorilla, and G. g. diehli in order to investigate geographic diversity. Skeletal elements included the humerus, radius, third metacarpal, third proximal hand phalanx, femur, tibia, calcaneus, first metatarsal, third metatarsal, and third proximal foot phalanx. Comparisons of means and principal components analyses clearly differentiate eastern and western gorillas, indicating that eastern gorillas have absolutely and relatively smaller hands and feet, among other differences. Gorilla subspecies and populations cluster consistently by species, although G. g. diehli may be similar to the eastern gorillas in having small hands and feet. The subspecies of G. beringei are distinguished less strongly and by different variables than the two gorilla species. Populations of G. b. graueri are variable, and Kahuzi and Tshiaberimu specimens do not cluster together. Results support the possible influence of higher-altitude Pleistocene refugia on patterns of geographic variation in gorillas. Copyright © 2016 Elsevier Ltd. All rights reserved.

Jasminum sambac flower absolutes from India and China--geographic variations.

PubMed

Braun, Norbert A; Sim, Sherina

2012-05-01

Seven Jasminum sambac flower absolutes from different locations in the southern Indian state of Tamil Nadu were analyzed using GC and GC-MS. Focus was placed on 41 key ingredients to investigate geographic variations in this species. These seven absolutes were compared with an Indian bud absolute and commercially available J. sambac flower absolutes from India and China. All absolutes showed broad variations for the 10 main ingredients between 8% and 96%. In addition, the odor of Indian and Chinese J. sambac flower absolutes were assessed.

The organisation, operational dynamics and structure of female sex work in Pakistan.

PubMed

Emmanuel, Faran; Thompson, Laura H; Athar, Uzma; Salim, Momina; Sonia, Altaf; Akhtar, Naeem; Blanchard, James F

2013-09-01

Pakistan is known to have large populations of female sex workers (FSWs) with considerable geographic heterogeneity in their characteristics. In this paper, we describe the social organisation and structural patterns of female sex work in different geographic regions of Pakistan. We report geographic and network mapping data collected among FSWs in 15 cities across Pakistan in 2011 as part of the Canada-Pakistan HIV/AIDS Surveillance Project. A total number of 89 178 FSWs were estimated in the target cities for an average of 7.2 FSWs per 1000 adult males. 55% of the estimated number of FSWs concentrated in Karachi and Lahore. Based on the operations of female sex work, two major typologies of FSWs were identified: establishment-based and non-establishment-based. FSWs were further subtyped into those operating through brothels, homes, kothikhanas, streets and by cell phone. Cities varied considerably in terms of predominance of different FSW typologies. There is considerable heterogeneity among FSWs in Pakistan, geographically and in terms of operational typology. Understanding the social organisation of sex work and the influence of social-cultural and legal factors in Pakistan is essential for the design of HIV prevention programmes and other services for FSWs.

Current issues in ALS epidemiology: Variation of ALS occurrence between populations and physical activity as a risk factor.

PubMed

Luna, J; Logroscino, G; Couratier, P; Marin, B

2017-05-01

Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disease with a fatal outcome. This review aims to report key epidemiological features of ALS in relation to the hypothesis of variation between populations, to summarize environmental hypothesis and to highlight current issues that deserve much considerations. Epidemiological ALS studies have shown a variation of incidence, mortality and prevalence between geographical areas and different populations. These data could support the notion that genetic factors, especially populations' ancestries, along with environmental and lifestyle factors, play a significant role in the occurrence of the disease. To date, there is no strong evidence to confirm an association between a particular environmental factor and ALS. Physical activity (PA) has been extensively evaluated. Recent studies support with the best evidence level that PA in general population is not a risk factor for ALS. However, further research is needed to clarify the association of PA in some occupations and some athletic activities. Epidemiological research based on multicenter international collaboration is essential to provide new data on ALS especially in some regions of the world that are to date poorly represented in the ALS literature. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Natural mode of horizontal transmission of bovine leukemia virus (BLV): the potential role of tabanids (Tabanus spp.).

PubMed

Manet, G; Guilbert, X; Roux, A; Vuillaume, A; Parodi, A L

1989-10-01

In order to evaluate the potential role of hematophagous insects in the natural spreading of bovine leukemia virus (BLV) infection in cattle, a 2-year survey was carried out involving sequential serological tests on 3328 cattle in three different areas. A parallel entomological study was run over the same period, using continuous trapping, in order to determine both the density and variations of horsefly (Tabanus spp.) populations in the close vicinity of the herds. After statistical analysis, this space-time study showed that: (1) There is a significant positive geographical correlation between the rate of incidence of BLV infection and the density of the horsefly population. (2) Seasonal variations in the incidence rate exist; the highest rates are generally observed during summer (from July of September), and the lowest during winter, spring and early summer (from November to mid-July). (3) There is a time link between the rate of sero-conversion and the variations in activity of the horsefly population. All these data combined would appear to indicate that tabanids play a considerable role in the spread of BLV under natural conditions.

42 CFR 412.316 - Geographic adjustment factors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 2 2010-10-01 2010-10-01 false Geographic adjustment factors. 412.316 Section 412... Costs § 412.316 Geographic adjustment factors. (a) Local cost variation. CMS adjusts for local cost... part. The adjustment factor equals the hospital wage index value applicable to the hospital raised to...

Limited Phylogeographic Signal in Sex-Linked and Autosomal Loci Despite Geographically, Ecologically, and Phenotypically Concordant Structure of mtDNA Variation in the Holarctic Avian Genus Eremophila

PubMed Central

Drovetski, Sergei V.; Raković, Marko; Semenov, Georgy; Fadeev, Igor V.; Red’kin, Yaroslav A.

2014-01-01

Phylogeographic studies of Holarctic birds are challenging because they involve vast geographic scale, complex glacial history, extensive phenotypic variation, and heterogeneous taxonomic treatment across countries, all of which require large sample sizes. Knowledge about the quality of phylogeographic information provided by different loci is crucial for study design. We use sequences of one mtDNA gene, one sex-linked intron, and one autosomal intron to elucidate large scale phylogeographic patterns in the Holarctic lark genus Eremophila. The mtDNA ND2 gene identified six geographically, ecologically, and phenotypically concordant clades in the Palearctic that diverged in the Early - Middle Pleistocene and suggested paraphyly of the horned lark (E. alpestris) with respect to the Temminck's lark (E. bilopha). In the Nearctic, ND2 identified five subclades which diverged in the Late Pleistocene. They overlapped geographically and were not concordant phenotypically or ecologically. Nuclear alleles provided little information on geographic structuring of genetic variation in horned larks beyond supporting the monophyly of Eremophila and paraphyly of the horned lark. Multilocus species trees based on two nuclear or all three loci provided poor support for haplogroups identified by mtDNA. The node ages calculated using mtDNA were consistent with the available paleontological data, whereas individual nuclear loci and multilocus species trees appeared to underestimate node ages. We argue that mtDNA is capable of discovering independent evolutionary units within avian taxa and can provide a reasonable phylogeographic hypothesis when geographic scale, geologic history, and phenotypic variation in the study system are too complex for proposing reasonable a priori hypotheses required for multilocus methods. Finally, we suggest splitting the currently recognized horned lark into five Palearctic and one Nearctic species. PMID:24498139

Geographical variation in dementia: systematic review with meta-analysis

PubMed Central

Russ, Tom C; Batty, G David; Hearnshaw, Gena F; Fenton, Candida; Starr, John M

2012-01-01

Background Geographical variation in dementia prevalence and incidence may indicate important socio-environmental contributions to dementia aetiology. However, previous comparisons have been hampered by combining studies with different methodologies. This review systematically collates and synthesizes studies examining geographical variation in the prevalence and incidence of dementia based on comparisons of studies using identical methodologies. Methods Papers were identified by a comprehensive electronic search of relevant databases, scrutinising the reference sections of identified publications, contacting experts in the field and re-examining papers already known to us. Identified articles were independently reviewed against inclusion/exclusion criteria and considered according to geographical scale. Rural/urban comparisons were meta-analysed. Results Twelve thousand five hundred and eighty records were reviewed and 51 articles were included. Dementia prevalence and incidence varies at a number of scales from the national down to small areas, including some evidence of an effect of rural living [prevalence odds ratio (OR) = 1.11, 90% confidence interval (CI) 0.79–1.57; incidence OR = 1.20, 90% CI 0.84–1.71]. However, this association of rurality was stronger for Alzheimer disease, particularly when early life rural living was captured (prevalence OR = 2.22, 90% CI 1.19–4.16; incidence OR = 1.64, 90% CI 1.08–2.50). Conclusions There is evidence of geographical variation in rates of dementia in affluent countries at a variety of geographical scales. Rural living is associated with an increased risk of Alzheimer disease, and there is a suggestion that early life rural living further increases this risk. However, the fact that few studies have been conducted in resource-poor countries limits conclusions. PMID:22798662

Adjusting for geographic variation in observational comparative effectiveness studies: a case study of antipsychotics using state Medicaid data.

PubMed

Root, Elisabeth Dowling; Thomas, Deborah S K; Campagna, Elizabeth J; Morrato, Elaine H

2014-08-27

Area-level variation in treatment and outcomes may be a potential source of confounding bias in observational comparative effectiveness studies. This paper demonstrates how to use exploratory spatial data analysis (ESDA) and spatial statistical methods to investigate and control for these potential biases. The case presented compares the effectiveness of two antipsychotic treatment strategies: oral second-generation antipsychotics (SGAs) vs. long-acting paliperiodone palmitate (PP). A new-start cohort study was conducted analyzing patient-level administrative claims data (8/1/2008-4/30/2011) from Missouri Medicaid. ESDA techniques were used to examine spatial patterns of antipsychotic prescriptions and outcomes (hospitalization and emergency department (ED) visits). Likelihood of mental health-related outcomes were compared between patients starting PP (N = 295) and oral SGAs (N = 8,626) using multilevel logistic regression models adjusting for patient composition (demographic and clinical factors) and geographic region. ESDA indicated significant spatial variation in antipsychotic prescription patterns and moderate variation in hospitalization and ED visits thereby indicating possible confounding by geography. In the multilevel models for this antipsychotic case example, patient composition represented a stronger source of confounding than geographic context. Because geographic variation in health care delivery is ubiquitous, it could be a comparative effectiveness research (CER) best practice to test for possible geographic confounding in observational data. Though the magnitude of the area-level geography effects were small in this case, they were still statistically significant and should therefore be examined as part of this observational CER study. More research is needed to better estimate the range of confounding due to geography across different types of observational comparative effectiveness studies and healthcare utilization outcomes.

Geographic variation in fee-for-service medicare beneficiaries' medical costs is largely explained by disease burden.

PubMed

Reschovsky, James D; Hadley, Jack; Romano, Patrick S

2013-10-01

Control for area differences in population health (casemix adjustment) is necessary to measure geographic variations in medical spending. Studies use various casemix adjustment methods, resulting in very different geographic variation estimates. We study casemix adjustment methodological issues and evaluate alternative approaches using claims from 1.6 million Medicare beneficiaries in 60 representative communities. Two key casemix adjustment methods-controlling for patient conditions obtained from diagnoses on claims and expenditures of those at the end of life-were evaluated. We failed to find evidence of bias in the former approach attributable to area differences in physician diagnostic patterns, as others have found, and found that the assumption underpinning the latter approach-that persons close to death are equally sick across areas-cannot be supported. Diagnosis-based approaches are more appropriate when current rather than prior year diagnoses are used. Population health likely explains more than 75% to 85% of cost variations across fixed sets of areas.

Single nucleotide polymorphism (SNP) variation of wolves (Canis lupus) in Southeast Alaska and comparison with wolves, dogs, and coyotes in North America.

PubMed

Cronin, Matthew A; Cánovas, Angela; Bannasch, Danika L; Oberbauer, Anita M; Medrano, Juan F

2015-01-01

There is considerable interest in the genetics of wolves (Canis lupus) because of their close relationship to domestic dogs (C. familiaris) and the need for informed conservation and management. This includes wolf populations in Southeast Alaska for which we determined genotypes of 305 wolves at 173662 single nucleotide polymorphism (SNP) loci. After removal of invariant and linked SNP, 123801 SNP were used to quantify genetic differentiation of wolves in Southeast Alaska and wolves, coyotes (C. latrans), and dogs from other areas in North America. There is differentiation of SNP allele frequencies between the species (wolves, coyotes, and dogs), although differentiation is relatively low between some wolf and coyote populations. There are varying levels of differentiation among populations of wolves, including low differentiation of wolves in interior Alaska, British Columbia, and the northern US Rocky Mountains. There is considerable differentiation of SNP allele frequencies of wolves in Southeast Alaska from wolves in other areas. However, wolves in Southeast Alaska are not a genetically homogeneous group and there are comparable levels of genetic differentiation among areas within Southeast Alaska and between Southeast Alaska and other geographic areas. SNP variation and other genetic data are discussed regarding taxonomy and management. © The American Genetic Association 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Columbia River White Sturgeon Genetics and Early Life History: Population Segregation and Juvenile Feeding Behavior, 1987 Final Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brannon, Ernest L.

1988-06-01

The geographic area of the genetics study broadly covered the distribution range of sturgeon in the Columbia from below Bonneville Dam at Ilwaco at Lake Roosevelt, the Upper Snake River, and the Kootenai River. The two remote river sections provided data important for enhancement considerations. There was little electrophoretic variation seen among individuals from the Kootenai River. Upper Snake river sturgeon showed a higher percentage of polymorphic loci than the Kootenai fish, but lower than the other areas in the Columbia River we sampled. Sample size was increased in both Lake Roosevelt and at Electrophoretic variation was specific to anmore » individual sampling area in several cases and this shaped our conclusions. The 1987 early life history studies concentrated on the feeding behavior of juvenile sturgeon. The chemostimulant components in prey attractive to sturgeon were examined, and the sensory systems utilized by foraging sturgeon were determined under different environmental conditions. These results were discussed with regard to the environmental changes that have occurred in the Columbia River. Under present river conditions, the feeding mechanism of sturgeon is more restricted to certain prey types, and their feeding range may be limited. In these situations, enhancement measures cannot be undertaken without consideration given to the introduction of food resources that will be readily available under present conditions. 89 refs., 7 figs., 11 tabs.« less

The U.S. Radiologist Workforce: An Analysis of Temporal and Geographic Variation by Using Large National Datasets.

PubMed

Rosenkrantz, Andrew B; Hughes, Danny R; Duszak, Richard

2016-04-01

To determine recent trends related to temporal as well as national and statewide geographic variation in the U.S. radiologist and radiology resident workforce. This retrospective HIPAA-compliant study was exempted from the internal review board. Federal Area Health Resources Files and Medicare 5% research identifiable files were used to compute parameters related to the radiologist workforce. Geographic variation and annual temporal trends were analyzed. Pearson and Spearman correlations were assessed. Nationally, the number of radiology trainees increased 84.2% from a nadir in 1997 (3080 trainees) to 2011 (5674 trainees) and showed high state-to-state variation (range, 0-678 trainees in 2011). However, total radiologists nationally increased 39.2% from 1995 (27 906 radiologists) to 2011 (38 875 radiologists), and radiologists per 100 000 population nationally increased by 7.5% from 1995 (10.62%) to 2011 (11.42%), while showing high state-to-state variation (highest-to-lowest state ratio of 4.3). Radiologists' share of the overall physician workforce declined nationally by 8.8% from 1995 (4.0%) to 2011 (3.7%), with moderate state-to-state variation (highest-to-lowest state ratio of 1.7). Radiology trainee numbers exhibited weak-to-moderate positive state-by-state correlation with radiologists per 100 000 population (r = 0.292-0.532), but moderate-to-strong inverse correlation with the percentage of radiologists in rural practice (r = -0.464 to -0.635). Although the number of radiology trainees dramatically increased, radiologists per 100 000 population increased only slightly, and radiologists' share of the overall physician workforce declined. State-to-state variations in radiologist and radiology resident workforces are high, which suggests a potential role for geographic redistribution rather than changes in the overall workforce size.

Geographic variations in hospital charges and Medicare payments for major joint arthroplasty.

PubMed

Thakore, Rachel V; Greenberg, Sarah E; Bulka, Catherine M; Ehrenfeld, Jesse M; Obremskey, William T; Sethi, Manish K

2015-05-01

National data on hospital-level charges and Medicare payments have shown that joint arthroplasty is the most common surgical procedure among the elderly. Yet, no study has investigated micro and macro level geographic variations in hospital charges and payment. We used the Medicare Provider Charge Data to investigate Medicare payments and charges for 2750 hospitals accounting for 427,207 patients who underwent major joint arthroplasty and 932 hospitals for 18,714 patients who had a complication/comorbidity. We found a significant difference in hospital charges and payments based on geographic region (P<0.001). We concluded that hospital charges demonstrate a high variability even when using areas to control for differences in hospital wages and high variation in reimbursements in some areas remains unexplained by Medicare's current method of calculating reimbursement. Published by Elsevier Inc.

"Magnetic" termite mound surfaces are oriented to suit wind and shade conditions.

PubMed

Jacklyn, Peter M

1992-09-01

The termites Amitermes meridionalis and A. laurensis construct remarkable meridional or "magnetic" mounds in northern Australia. These mounds vary geographically in mean orientation in a manner that suggests such variation is an adaptive response to local environmental conditions. Theoretical modelling of solar irradiance and mound rotation experiments show that maintenance of an eastern face temperature plateau during the dry season is the most likely physical basis for the mound orientation response. Subsequent heat transfer analysis shows that habitat wind speed and shading conditions also affect face temperature gradients such as the rate of eastern face temperature change. It is then demonstrated that the geographic variation in mean mound orientation follows the geographic variation in long-term wind speed and shading conditions across northern Australia such that an eastern face temperature plateau is maintained in all locations.

The Impact of Child-Care Subsidies on Child Development: Evidence from Geographic Variation in the Distance to Social Service Agencies

ERIC Educational Resources Information Center

Herbst, Chris M.; Tekin, Erdal

2016-01-01

In this paper, we examine the impact of U.S. child-care subsidies on the cognitive and behavioral development of children in low-income female-headed families. We identify the effect of subsidy receipt by exploiting geographic variation in the distance that families must travel from home to reach the nearest social service agency that administers…

Geographical and experimental contexts modulate the effect of warming on top-down control: a meta-analysis.

PubMed

Marino, Nicholas Dos Anjos Cristiano; Romero, Gustavo Quevedo; Farjalla, Vinicius Fortes

2018-03-01

Ecologists have extensively investigated the effect of warming on consumer-resource interactions, with experiments revealing that warming can strengthen, weaken or have no net effect on top-down control of resources. These experiments have inspired a body of theoretical work to explain the variation in the effect of warming on top-down control. However, there has been no quantitative attempt to reconcile theory with outcomes from empirical studies. To address the gap between theory and experiment, we performed a meta-analysis to examine the combined effect of experimental warming and top-down control on resource biomass and determined potential sources of variation across experiments. We show that differences in experimental outcomes are related to systematic variation in the geographical distribution of studies. Specifically, warming strengthened top-down control when experiments were conducted in colder regions, but had the opposite effect in warmer regions. Furthermore, we found that differences in the thermoregulation strategy of the consumer and openness of experimental arenas to dispersal can contribute to some deviation from the overall geographical pattern. These results reconcile empirical findings and support the expectation of geographical variation in the response of consumer-resource interactions to warming. © 2018 John Wiley & Sons Ltd/CNRS.

Differences in protein expression among five species of stream stonefly (Plecoptera) along a latitudinal gradient in Japan.

PubMed

Gamboa, Maribet; Tsuchiya, Maria Claret; Matsumoto, Suguru; Iwata, Hisato; Watanabe, Kozo

2017-11-01

Proteome variation among natural populations along an environmental gradient may provide insights into how the biological functions of species are related to their local adaptation. We investigated protein expression in five stream stonefly species from four geographic regions along a latitudinal gradient in Japan with varying climatic conditions. The extracted proteins were separated by two-dimensional gel electrophoresis and identified by matrix-assisted laser desorption/ionization of time-of-flight (MALDI TOF/TOF), yielding 446 proteins. Low interspecies variation in the proteome profiles was observed among five species within geographical regions, presumably due to the co-occurring species sharing the environments. However, large spatial variations in protein expression were found among four geographic regions, suggesting strong regulation of protein expression in heterogeneous environments, where the spatial variations were positively correlated with water temperature. We identified 21 unique proteins expressed specifically in a geographical region and six common proteins expressed throughout all regions. In warmer regions, metabolic proteins were upregulated, whereas proteins related to cold stress, the photoperiod, and mating were downregulated. Oxygen-related and energy-production proteins were upregulated in colder regions with higher altitudes. Thus, our proteomic approach is useful for identifying and understanding important biological functions related to local adaptations by populations of stoneflies. © 2017 Wiley Periodicals, Inc.

Geographic Variation of Chronic Kidney Disease Prevalence: Correlation with the Incidence of Renal Cell Carcinoma or Urothelial Carcinoma?

PubMed

Yap, Yit-Sheung; Chuang, Kai-Wen; Chiang, Chun-Ju; Chuang, Hung-Yi; Lu, Sheng-Nan

2015-01-01

The aim of this study is to evaluate whether geographic variations in the prevalence of late-stage chronic kidney disease (CKD) exist and are associated with incidence rates of renal cell carcinoma (RCC), upper tract urothelial carcinoma (UTUC), or lower tract urothelial carcinoma (LTUC). Prevalence rates of late-stage CKD for 366 townships (n > 30) in Taiwan were calculated for 1,518,241 and 1,645,151 subjects aged 40 years or older in years 2010 and 2009, respectively. Late-stage CKD prevalence in year 2010 was used as a training set and its age-adjusted standardized morbidity rates (ASMR) were divided into three groups as defined <1.76%, 1.76% ≤ ASMR < 2.64%, and ≥2.64%, respectively. Year 2009, defined as the validation set, was used to validate the results. The ASMR of late-stage CKD in years 2010 and 2009 were 1.76%, and 2.09%, respectively. Geographic variations were observed, with notably higher rates of disease in areas of the central, southwestern mountainside, and southeastern seaboard. There were no significant differences among different combined risk groups of RCC, UTUC, and LTUC incidence. The substantial geographic variations in the prevalence of late-stage CKD exist, but are not correlated with RCC, UTUC, or LTUC incidence.

A comparison of worldwide phonemic and genetic variation in human populations

PubMed Central

Creanza, Nicole; Ruhlen, Merritt; Pemberton, Trevor J.; Rosenberg, Noah A.; Feldman, Marcus W.; Ramachandran, Sohini

2015-01-01

Worldwide patterns of genetic variation are driven by human demographic history. Here, we test whether this demographic history has left similar signatures on phonemes—sound units that distinguish meaning between words in languages—to those it has left on genes. We analyze, jointly and in parallel, phoneme inventories from 2,082 worldwide languages and microsatellite polymorphisms from 246 worldwide populations. On a global scale, both genetic distance and phonemic distance between populations are significantly correlated with geographic distance. Geographically close language pairs share significantly more phonemes than distant language pairs, whether or not the languages are closely related. The regional geographic axes of greatest phonemic differentiation correspond to axes of genetic differentiation, suggesting that there is a relationship between human dispersal and linguistic variation. However, the geographic distribution of phoneme inventory sizes does not follow the predictions of a serial founder effect during human expansion out of Africa. Furthermore, although geographically isolated populations lose genetic diversity via genetic drift, phonemes are not subject to drift in the same way: within a given geographic radius, languages that are relatively isolated exhibit more variance in number of phonemes than languages with many neighbors. This finding suggests that relatively isolated languages are more susceptible to phonemic change than languages with many neighbors. Within a language family, phoneme evolution along genetic, geographic, or cognate-based linguistic trees predicts similar ancestral phoneme states to those predicted from ancient sources. More genetic sampling could further elucidate the relative roles of vertical and horizontal transmission in phoneme evolution. PMID:25605893

Geographic Variations in Incremental Costs of Heart Disease Among Medicare Beneficiaries, by Type of Service, 2012.

PubMed

Wakim, Rita; Ritchey, Matthew; Hockenberry, Jason; Casper, Michele

2016-12-29

Using 2012 data on fee-for-service Medicare claims, we documented regional and county variation in incremental standardized costs of heart disease (ie, comparing costs between beneficiaries with heart disease and beneficiaries without heart disease) by type of service (eg, inpatient, outpatient, post-acute care). Absolute incremental total costs varied by region. Although the largest absolute incremental total costs of heart disease were concentrated in southern and Appalachian counties, geographic patterns of costs varied by type of service. These data can be used to inform development of policies and payment models that address the observed geographic disparities.

[Geographical variation in the species Montivagum dihumerale and speciation in chigger mites (Acari: Trombiculidae)].

PubMed

Stekol'nikov, A A

2006-01-01

Intraspecific morphological variation of the chigger mite species Montivagum dihumerale (Traub et Nadchatram, 1967) is studied. Eco-geographic rules of the variation are revealed. General size of mites is found to be increased along with the rise of the high-mountain character of the landscape in the collection localities. The numbers of idiosomal setae are varied independently from the size parameters and geographically close populations are proved to be the most similar by these characters. At the same time, numbers of the setae of different types play the leading role in the discrimination of closely related Montivagum species, while the eco-geographical rules have not been found in this genus at the level of interspecific differences. As a result, the hypothesis is set up, that a significant degree of isolation of local populations separated from each other by high mountain ranges of the Central Asia is the main factor of speciation in the genus Montivagum. Regional character of this speciation mode is confirmed by the comparison with other chigger mites taxa.

Variation in performance on cry1Ab-transformed and nontransgenic rice varieties among populations of Scirpophaga incertulas (Lepidoptera: Pyralidae) from Luzon Island, Philippines.

PubMed

Bentur, J S; Cohen, M B; Gould, F

2000-12-01

We quantified variation in performance under greenhouse conditions among seven populations of Scirpophaga incertulas (Walker) from Luzon Island, Philippines, on three rice varieties: 'IR58' transformed with the cry1Ab gene from Bacillus thuringiensis Berliner, and nontransgenic IR58 and IR62. On IR62, S. incertutas performance did not differ among provinces for any of the 10 parameters measured, but there was a significant effect of town within province for one parameter, 20-d-old larval weight. Larval survival after 48 h on cy1Ab-transformed IR58 did not differ significantly among provinces, but did differ significantly among towns within a province. There was no geographic variation in larval survival after 48 h on control plants of IR58. Surviving insects from the cry1Ab-transformed IR58 were transferred to IR62 to complete development. There was no geographic variation in the percentage of insects completing development to adult emergence and the time required by the transferred female insects to complete development. However, there was variation among provinces in male developmental time. The absence of geographic variation on nontransgenic IR58 and the very limited variation on IR62 indicated that there was little variation in general vigor among the S. incertulas populations and thus that the variation in performance oil cry1Ab-transformed IR58 was probably attributable to differences in susceptibility to Cry1Ab.

A systematic review of geographical differences in management and outcomes for colorectal cancer in Australia.

PubMed

Ireland, Michael J; March, Sonja; Crawford-Williams, Fiona; Cassimatis, Mandy; Aitken, Joanne F; Hyde, Melissa K; Chambers, Suzanne K; Sun, Jiandong; Dunn, Jeff

2017-02-02

Australia and New Zealand have the highest incidence of colorectal cancer (CRC) in the world, presenting considerable health, economic, and societal burden. Over a third of the Australian population live in regional areas and research has shown they experience a range of health disadvantages that result in a higher disease burden and lower life expectancy. The extent to which geographical disparities exist in CRC management and outcomes has not been systematically explored. The present review aims to identify the nature of geographical disparities in CRC survival, clinical management, and psychosocial outcomes. The review followed PRISMA guidelines and searches were undertaken using seven databases covering articles between 1 January 1990 and 20 April 2016 in an Australian setting. Inclusion criteria stipulated studies had to be peer-reviewed, in English, reporting data from Australia on CRC patients and relevant to one of fourteen questions examining geographical variations in a) survival outcomes, b) patient and cancer characteristics, c) diagnostic and treatment characteristics and d) psychosocial and quality of life outcomes. Thirty-eight quantitative, two qualitative, and three mixed-methods studies met review criteria. Twenty-seven studies were of high quality, sixteen studies were of moderate quality, and no studies were found to be low quality. Individuals with CRC living in regional, rural, and remote areas of Australia showed poorer survival and experienced less optimal clinical management. However, this effect is likely moderated by a range of other factors (e.g., SES, age, gender) and did appear to vary linearly with increasing distance from metropolitan centres. No studies examined differences in use of stoma, or support with stomas, by geographic location. Overall, despite evidence of disparity in CRC survival and clinical management across geographic locations, the evidence was limited and at times inconsistent. Further, access to treatment and services may not be the main driver of disparities, with individual patient characteristics and type of region also playing an important role. A better understanding of factors driving ongoing and significant geographical disparities in cancer related outcomes is required to inform the development of effective interventions to improve the health and welfare of regional Australians.

Geographic Variations in Public Schools' Costs. Working Paper Series.

ERIC Educational Resources Information Center

Chambers, Jay G.

This report addresses the following question: How much more or less does it cost to provide the same levels of educational resources across different geographic locations in the United States? To answer this question, the report develops a comprehensive geographic cost-of-education index (GCEI) that focuses on the prices of inputs (personnel and…

Population genomics and the causes of local differentiation.

PubMed

Tonsor, Stephen J

2012-11-01

Exactly 50 years ago, a revolution in empirical population genetics began with the introduction of methods for detecting allelic variation using protein electrophoresis (Throckmorton 1962; Hubby 1963; Lewontin & Hubby 1966). These pioneering scientists showed that populations are chock-full of genetic variation. This variation was a surprise that required a re-thinking of evolutionary genetic heuristics. Understanding the causes for the maintenance of this variation became and remains a major area of research. In the process of addressing the causes, this same group of scientists documented geographical genetic structure (Prakash et al. 1969), spawning the continued accumulation of what is now a huge case study catalogue of geographical differentiation (e.g. Loveless & Hamrick 1984; Linhart & Grant 1996). Geographical differentiation is clearly quite common. Yet, a truly general understanding of the patterns in and causes of spatial genetic structure across the genome remains elusive. To what extent is spatial structure driven by drift and phylogeography vs. geographical differences in environmental sources of selection? What proportion of the genome participates? A general understanding requires range-wide data on spatial patterning of variation across the entire genome. In this issue of Molecular Ecology, Lasky et al. (2012) make important strides towards addressing these issues, taking advantage of three contemporary revolutions in evolutionary biology. Two are technological: high-throughput sequencing and burgeoning computational power. One is cultural: open access to data from the community of scientists and especially data sets that result from large collaborative efforts. Together, these developments may at last put answers within reach.

Comments on "Intraspecific and geographic variation of West Indian manatee (Trichechus manatus spp.) vocalizations" [J. Acoust. Soc. Am. 114, 66-69 (2003)].

PubMed

Sousa-Lima, Renata S

2006-06-01

This letter concerns the paper "Intraspecific and geographic variation of West Indian manatee (Trichechus manatus spp.) vocalizations" [Nowacek et al., J. Acoust. Soc. Am. 114, 66-69 (2003)]. The purpose here is to correct the fundamental frequency range and information on intraindividual variation in the vocalizations of Amazonian manatees reported by Nowacek et al. (2003) in citing the paper "Signature information and individual recognition in the isolation calls of Amazonian manatees, Trichechus inunguis (Mammalia: Sirenia)" [Sousa-Lima et al., Anim. Behav. 63, 301-310 (2002)].

Geographic variation in the black bear (Ursus americanus) in the eastern United States and Canada

USGS Publications Warehouse

Kennedy, M.L.; Kennedy, P.K.; Bogan, M.A.; Waits, J.L.

2002-01-01

The pattern of geographic variation in morphologic characters of the black bear (Ursus americanus) was assessed at 13 sites in the eastern United States and Canada. Thirty measurements from 206 males and 207 females were recorded to the nearest 0.01 mm using digital calipers and subjected to principal components analysis. A matrix of correlations among skull characters was computed, and the first 3 principal components were extracted. These accounted for 90.5% of the variation in the character set for males and 87.1% for females. Three-dimensional projection of localities onto principal components showed that, for males and females, largest individuals occurred in the more southern localities (e.g., males--Louisiana-Mississippi, eastern Texas; females--Louisiana-eastern Texas) and the smallest animals occurred in the northernmost locality (Quebec). Generally, bears were similar morphologically to those in nearby geographic areas. For males, correlations between morphologic variation and environmental factors indicated a significant relationship between size variation and mean January temperature, mean July temperature, mean annual precipitation, latitude, and actual evapotranspiration; for females, a significant relationship was observed between morphologic variation and mean annual temperature, mean January temperature, mean July temperature, latitude, and actual evapotranspiration. There was no significant correlation for either sex between environmental factors and projections onto components II and III.

Changes related to gender, geographic population and habitat in the antennal phenotype of Triatoma patagonica Del Ponte, 1929 (Hemiptera: Reduviidae).

PubMed

Rodríguez, Claudia S; Crocco, Liliana; Altamirano, Alejandra; Catalá, Silvia

2013-02-01

Triatomines undergo morphological changes as an adaptive response to different habitats (wild, peridomestic, domestic, laboratory). The characterization of the antennal phenotype provides information on intraspecific variation caused by geographical origin and/or habitat. Triatoma patagonica Del Ponte, 1929 is known to occur in peridomiciles of rural areas in Argentina, where it also invades non-colonized dwellings. Here we describe and compare the antennal phenotype of T. patagonica in populations of different geographic origin, and explore possible modifications induced by laboratory rearing with the aim of investigating the range of phenotypic variation of the species for the first time. Sixty antennas of adult males and females of T. patagonica belonging to two peridomiciliary populations of different geographical origin were analyzed. Four types of sensilla were observed in three antennal segments, showing sexual dimorphism in the species. The multivariate analysis separated the populations of similar habitat (peridomicile) but different geographical origin, without showing differences between the peridomiciliary and laboratory populations of the same geographical origin. These results suggest phenotypic plasticity in T. patagonica, which would allow the species to adapt to a wide range of habitats without having a close association with a given host and its environment. The range of antennal phenotypic variation of T. patagonica would also be an indicator of its current stage of adaptation to the human environment. Copyright © 2012 Elsevier B.V. All rights reserved.

A multilevel model for comorbid outcomes: obesity and diabetes in the US.

PubMed

Congdon, Peter

2010-02-01

Multilevel models are overwhelmingly applied to single health outcomes, but when two or more health conditions are closely related, it is important that contextual variation in their joint prevalence (e.g., variations over different geographic settings) is considered. A multinomial multilevel logit regression approach for analysing joint prevalence is proposed here that includes subject level risk factors (e.g., age, race, education) while also taking account of geographic context. Data from a US population health survey (the 2007 Behavioral Risk Factor Surveillance System or BRFSS) are used to illustrate the method, with a six category multinomial outcome defined by diabetic status and weight category (obese, overweight, normal). The influence of geographic context is partly represented by known geographic variables (e.g., county poverty), and partly by a model for latent area influences. In particular, a shared latent variable (common factor) approach is proposed to measure the impact of unobserved area influences on joint weight and diabetes status, with the latent variable being spatially structured to reflect geographic clustering in risk.

Geography of breast cancer incidence according to age & birth cohorts.

PubMed

Gregorio, David I; Ford, Chandler; Samociuk, Holly

2017-06-01

Geographic variation in breast cancer incidence across Connecticut was examined according to age and birth cohort -specific groups. We assigned each of 60,937 incident breast cancer cases diagnosed in Connecticut, 1986-2009, to one of 828 census tracts around the state. Global and local spatial statistics estimated rate variation across the state according to age and birth cohorts. We found the global distribution of incidence rates across places to be more heterogeneous for younger women and later birth cohorts. Concurrently, the spatial scan identified more locations with significantly high rates that pertained to larger proportions of at-risk women within these groups. Geographic variation by age groups was more pronounced than by birth cohorts. Geographic patterns of cancer incidence exhibit differences within and across age and birth cohorts. With the continued insights from descriptive epidemiology, our capacity to effectively limit spatial disparities in cancer will improve. Copyright © 2017 Elsevier Ltd. All rights reserved.

Geographical variation of St. Lucia Parrot flight vocalizations

USGS Publications Warehouse

Kleeman, Patrick M.; Gilardi, James D.

2005-01-01

Parrots are vocal learners and many species of parrots are capable of learning new calls, even as adults. This capability gives parrots the potential to develop communication systems that can vary dramatically over space. St. Lucia Parrot (Amazona versicolor) flight vocalizations were examined for geographic variation between four different sites on the island of St. Lucia. Spectrographic cross-correlation analysis of a commonly used flight vocalization, the p-chow call, demonstrated quantitative differences between sites. Additionally, the similarity of p-chows decreased as the distance between sites increased. Flight call repertoires also differed among sites; parrots at the Des Bottes and Quilesse sites each used one flight call unique to those sites, while parrots at the Barre de L'Isle site used a flight call that Quilesse parrots gave only while perched. It is unclear whether the vocal variation changed clinally with distance, or whether there were discrete dialect boundaries as in a congener, the Yellow-naped Parrot (Amazona auropalliata, Wright 1996). The geographical scale over which the St. Lucia Parrot's vocal variation occurred was dramatically smaller than that of the Yellow-naped Parrot. Similar patterns of fine-scale vocal variation may be more widespread among other parrot species in the Caribbean than previously documented.

Unnecessary surgery.

PubMed Central

Leape, L L

1989-01-01

The extent of unnecessary surgery has been the object of considerable speculation and occasional wild accusation in recent years. Most evidence of the existence of unnecessary surgery, such as information from studies of geographic variations and the results of second surgical opinion programs, is circumstantial. However, results from the few studies that have measured unnecessary surgery directly indicate that for some highly controversial operations the fraction that are unwarranted could be as high as 30 percent. Most unnecessary surgery results from physician uncertainty about the effectiveness of an operation. Elimination of this uncertainty requires more efficient production and dissemination of scientific information about clinical effectiveness. In the absence of adequate data from scientific studies, the use of a consensus of expert opinion, disseminated by means of comprehensive practice guidelines, offers the best opportunity to identify and eliminate unnecessary surgery. PMID:2668237

Geographic, temporal, and age-specific variation in diets of Glaucous Gulls in western Alaska

USGS Publications Warehouse

Schmutz, J.A.; Hobson, K.A.

1998-01-01

We collected boluses and food remains of adult Glaucous Gulls (Larus hyperboreus) at or near nests and chicks, and digestive tracts from adults at three sites on the Yukon-Kuskokwim Delta, Alaska that differed in proximity to marine and terrestrial foods. We observed both geographic and temporal variation in diet; gulls consumed proportionately more terrestrial prey after peak hatch in late June, and gulls near the coast consumed proportionately more marine prey than gulls at two inland areas. Goslings occurred in > 60% of all samples from these inland areas. We compared these data to those from a previous study in western Alaska and found no marked differences. Evidence for similar patterns of geographic and temporal variation in diet was found using measurements of stable-carbon and nitrogen isotopes in gull and prey tissues. Stable isotope analysis further revealed that adult gulls consumed proportionately more marine prey (saffron cod, Eleginus gracilis) than they fed to their young. Using isotopic models, we estimated that 7-22% and 10-23% of the diet of adult and juvenile Glaucous Gulls, respectively, was comprised of terrestrial species. In addition to significant age-related variation, dietary estimates varied among geographic areas and between pre- and post-hatch periods. Overall, our isotopic estimates of the contribution of terrestrial prey to the diet of Glaucous Gulls was less than what may be inferred from conventional methods of diet analysis. Our study emphasizes the benefit of combining stable-isotope and conventional analyses to infer temporal and geographic changes in diet of wild birds and other organisms.

Venom variation and chemoreception of the viperid Agkistrodon contortrix: evidence for adaptation?

PubMed

Greenbaum, Eli; Galeva, Nadezhda; Jorgensen, Michael

2003-08-01

Previous studies of chemoreceptive behavior in vipers suggest that snakes focus on the scent of envenomated tissue to track their prey following envenomation. Other studies have indicated a correlation between qualitative differences in venom biochemistry and geographic variation in diet. The North American copperhead (Agkistrodon contortrix) varies geographically in diet and venom biochemistry; snakes were collected from three populations (Kansas, Texas, and Louisiana) that are known to have different prey preferences. Behavioral experiments were conducted to assess whether copperheads preferred envenomated prey more than nonenvenomated prey, as do other species of vipers studied thus far. Additional experiments tested the ability of copperheads to distinguish between envenomated prey from different geographic populations, and between geographic populations of copperheads and two other species of viper. Results indicated that copperheads prefer envenomated prey to nonenvenomated prey. In envenomated-prey discrimination experiments, copperheads distinguished between envenomated prey from different geographic populations, and some snakes distinguished envenomated prey of A. contortrix from those of A. piscivorns and Sistrurus catenatus. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to study the variation of venom biochemistry in this species and two other taxa (A. piscivorus and S. catenatus), and confirmed intraspecific and interspecific variation of venom proteins. Relative potency of the venom from different populations as indicated by time to immobilization experiments was in the order: Louisiana > Texas > Kansas. The relative potency of the venom from each population matched the order of preference in the chemoreception experiments. These results suggest that chemoreception is sensitive to subtle differences in venom biochemistry and may reflect adaptation to improve efficiency of finding envenomated prey.

Worldwide Mycotoxins Exposure in Pig and Poultry Feed Formulations

PubMed Central

Guerre, Philippe

2016-01-01

The purpose of this review is to present information about raw materials that can be used in pig and poultry diets and the factors responsible for variations in their mycotoxin contents. The levels of mycotoxins in pig and poultry feeds are calculated based on mycotoxin contamination levels of the raw materials with different diet formulations, to highlight the important role the stage of production and the raw materials used can have on mycotoxins levels in diets. Our analysis focuses on mycotoxins for which maximum tolerated levels or regulatory guidelines exist, and for which sufficient contamination data are available. Raw materials used in feed formulation vary considerably depending on the species of animal, and the stage of production. Mycotoxins are secondary fungal metabolites whose frequency and levels also vary considerably depending on the raw materials used and on the geographic location where they were produced. Although several reviews of existing data and of the literature on worldwide mycotoxin contamination of food and feed are available, the impact of the different raw materials used on feed formulation has not been widely studied. PMID:27886128

Nematode assemblages associated with the parthenogenetic lizard Ameivula nativo in six restinga areas along the eastern coast of Brazil.

PubMed

Menezes, V A; Mascarenhas, J C; Vrcibradic, D; Rocha, C F D

2017-10-04

We surveyed the nematode assemblages associated with populations of the parthenogenetic whiptail lizard Ameivula nativo from six coastal restinga areas in eastern Brazil: Setiba, Comboios and Guriri (State of Espirito Santo) and Guaratiba, Prado and Maraú (State of Bahia). A total of five nematode species (Physaloptera retusa, Physalopteroides venancioi, Skrjabinelazia intermedia, Subulura lacertilia and Parapharyngodon sp.) were recorded from the six different populations of A. nativo. There was considerable variation in overall prevalence of infection (1-42%) among study sites, but geographical distance among areas did not influence similarity in the composition of nematode assemblages. Overall intensity of infection was not affected by lizard body size and did not seem to affect host body condition, based on pooled data of all populations. The studied populations of the unisexual A. nativo had relatively low prevalences and intensities of infection compared to some bisexual congeners and to sympatric lizards from other families for which such data are available. We believe that the low richness of the nematode fauna associated with A. nativo, both locally and regionally, may reflect its narrow geographic distribution and the low diversity of habitats it occupies.

Morphological and Genetic Evidence for Multiple Evolutionary Distinct Lineages in the Endangered and Commercially Exploited Red Lined Torpedo Barbs Endemic to the Western Ghats of India

PubMed Central

Dahanukar, Neelesh; Anvar Ali, Palakkaparambil Hamsa; Tharian, Josin; Raghavan, Rajeev; Antunes, Agostinho

2013-01-01

Red lined torpedo barbs (RLTBs) (Cyprinidae: Puntius) endemic to the Western Ghats Hotspot of India, are popular and highly priced freshwater aquarium fishes. Two decades of indiscriminate exploitation for the pet trade, restricted range, fragmented populations and continuing decline in quality of habitats has resulted in their ‘Endangered’ listing. Here, we tested whether the isolated RLTB populations demonstrated considerable variation qualifying to be considered as distinct conservation targets. Multivariate morphometric analysis using 24 size-adjusted characters delineated all allopatric populations. Similarly, the species-tree highlighted a phylogeny with 12 distinct RLTB lineages corresponding to each of the different riverine populations. However, coalescence-based methods using mitochondrial DNA markers identified only eight evolutionarily distinct lineages. Divergence time analysis points to recent separation of the populations, owing to the geographical isolation, more than 5 million years ago, after the lineages were split into two ancestral stocks in the Paleocene, on north and south of a major geographical gap in the Western Ghats. Our results revealing the existence of eight evolutionarily distinct RLTB lineages calls for the re-determination of conservation targets for these cryptic and endangered taxa. PMID:23894533

Mapping Geographic Variation in Infant Mortality and Related Black–White Disparities in the US

PubMed Central

Rossen, Lauren M.; Khan, Diba; Schoendorf, Kenneth C.

2017-01-01

Background In the US, black infants remain more than twice as likely as white infants to die in the first year of life. Previous studies of geographic variation in infant mortality disparities have been limited to large metropolitan areas where stable estimates of infant mortality rates by race can be determined, leaving much of the US unexplored. Methods The objective of this analysis was to describe geographic variation in county-level racial disparities in infant mortality rates across the 48 contiguous US states and District of Columbia using national linked birth and infant death period files (2004–2011). We implemented Bayesian shared component models in OpenBUGS, borrowing strength across both spatial units and racial groups. We mapped posterior estimates of mortality rates for black and white infants as well as relative and absolute disparities. Results Black infants had higher infant mortality rates than white infants in all counties, but there was geographic variation in the magnitude of both relative and absolute disparities. The mean difference between black and white rates was 5.9 per 1,000 (median: 5.8, interquartile range: 5.2 to 6.6 per 1,000), while those for black infants were 2.2 times higher than for white infants (median: 2.1, interquartile range: 1.9–2.3). One quarter of the county-level variation in rates for black infants was shared with white infants. Conclusions Examining county-level variation in infant mortality rates among black and white infants and related racial disparities may inform efforts to redress inequities and reduce the burden of infant mortality in the US. PMID:27196804

Estimated impact and cost-effectiveness of rotavirus vaccination in India: effects of geographic and economic disparities.

PubMed

Rheingans, Richard; Anderson, John D; Anderson, Benjamin; Chakraborty, Poulomy; Atherly, Deborah; Pindolia, Deepa

2014-08-11

India accounts for 23% of global rotavirus mortality in under-five children, with more than 100,000 deaths from rotavirus annually. Introduction of a vaccine in India is considered to be the most effective intervention for preventing rotavirus mortality. Recent research suggests that there is considerable variation in rotavirus mortality burden across regional, gender and socio-economic subpopulations within India. In addition, there is potential variability in who would likely receive rotavirus vaccine if introduced. We use available household data to estimate heterogeneity in rotavirus mortality risk, vaccination benefits, and cost-effectiveness across geographic and socio-economic groups within India. We account for heterogeneity by modeling estimated three-dose routine vaccinations as a proxy for a generalized rotavirus vaccine, and mortality for subpopulations of children aggregated by region and state, socio-economic status and sex, separately. Results are presented for six geographic regions and for Bihar, Uttar Pradesh, and Madhya Pradesh, three high mortality states accounting for 56% of national mortality estimates. Impact estimates accounting for disparities predict rotavirus vaccine introduction will prevent 35,000 deaths at an average cost of $118/DALY averted (7292 INR/DALY averted). Rotavirus vaccines are most cost-effective for the poor living in high mortality regions and states. Reductions in geographic and socio-economic disparities based on regional estimates could prevent an additional 9400 deaths annually, while reductions in socio-economic disparities in the three highest morality states alone could prevent an additional 10,600 deaths annually. Understanding the impact of heterogeneity can help improve strategies to maximize the benefits of rotavirus vaccination introduction, leading to fewer lives lost as a result of rotavirus disease. Copyright © 2014. Published by Elsevier Ltd.

Genomic Analysis of Phylotype I Strain EP1 Reveals Substantial Divergence from Other Strains in the Ralstonia solanacearum Species Complex

PubMed Central

Li, Peng; Wang, Dechen; Yan, Jinli; Zhou, Jianuan; Deng, Yinyue; Jiang, Zide; Cao, Bihao; He, Zifu; Zhang, Lianhui

2016-01-01

Ralstonia solanacearum species complex is a devastating group of phytopathogens with an unusually wide host range and broad geographical distribution. R. solanacearum isolates may differ considerably in various properties including host range and pathogenicity, but the underlying genetic bases remain vague. Here, we conducted the genome sequencing of strain EP1 isolated from Guangdong Province of China, which belongs to phylotype I and is highly virulent to a range of solanaceous crops. Its complete genome contains a 3.95-Mb chromosome and a 2.05-Mb mega-plasmid, which is considerably bigger than reported genomes of other R. solanacearum strains. Both the chromosome and the mega-plasmid have essential house-keeping genes and many virulence genes. Comparative analysis of strain EP1 with other 3 phylotype I and 3 phylotype II, III, IV strains unveiled substantial genome rearrangements, insertions and deletions. Genome sequences are relatively conserved among the 4 phylotype I strains, but more divergent among strains of different phylotypes. Moreover, the strains exhibited considerable variations in their key virulence genes, including those encoding secretion systems and type III effectors. Our results provide valuable information for further elucidation of the genetic basis of diversified virulences and host range of R. solanacearum species. PMID:27833603

Genetic diversity in three endangered pitcher plant species (Sarracenia; Sarraceniaceae) is lower than widespread congeners.

PubMed

Furches, M Steven; Small, Randall L; Furches, Anna

2013-10-01

Narrow-ranging, rare species often exhibit levels of genetic diversity lower than more common or widespread congeners. These taxa are at increased risk of extinction due to threats associated with natural as well as anthropogenic events. We assessed genetic variation in three federally endangered Sarracenia species. We discuss maintenance of genetic diversity and evolutionary implications of rarity. • We analyzed three noncoding chloroplast regions and nine microsatellite loci in populations spanning the geographic ranges of S. oreophila, S. alabamensis, and S. jonesii. The same microsatellite loci were used to examine a single field site of three more widespread species (S. alata, S. leucophylla, and S. rubra subsp. wherryi). • All three endangered species have experienced reductions in population size and numbers. All show considerably less variation than more widespread members of the genus. Sarracenia alabamensis maintains the greatest microsatellite variation but has the fewest remaining populations and may be under the greatest threat. More widespread S. oreophila maintains surprising chloroplast diversity, yet exhibits little microsatellite diversity. Sarracenia jonesii lacks chloroplast diversity, yet maintains greater microsatellite diversity than S. oreophila. • The three endangered species differ in levels and structure of diversity, yet not in predictable ways, emphasizing that unique demographic and ecological histories, rather than current distribution and population size, best explain present patterns of genetic variation. Maintenance of remaining genetic variation is important, but preventing further habitat loss and degradation is critical.

Spatial and temporal variation at major histocompatibility complex class IIB genes in the endangered Blakiston's fish owl.

PubMed

Kohyama, Tetsuo I; Omote, Keita; Nishida, Chizuko; Takenaka, Takeshi; Saito, Keisuke; Fujimoto, Satoshi; Masuda, Ryuichi

2015-01-01

Quantifying intraspecific genetic variation in functionally important genes, such as those of the major histocompatibility complex (MHC), is important in the establishment of conservation plans for endangered species. The MHC genes play a crucial role in the vertebrate immune system and generally show high levels of diversity, which is likely due to pathogen-driven balancing selection. The endangered Blakiston's fish owl (Bubo blakistoni) has suffered marked population declines on Hokkaido Island, Japan, during the past several decades due to human-induced habitat loss and fragmentation. We investigated the spatial and temporal patterns of genetic diversity in MHC class IIβ genes in Blakiston's fish owl, using massively parallel pyrosequencing. We found that the Blakiston's fish owl genome contains at least eight MHC class IIβ loci, indicating recent gene duplications. An analysis of sequence polymorphism provided evidence that balancing selection acted in the past. The level of MHC variation, however, was low in the current fish owl populations in Hokkaido: only 19 alleles were identified from 174 individuals. We detected considerable spatial differences in MHC diversity among the geographically isolated populations. We also detected a decline of MHC diversity in some local populations during the past decades. Our study demonstrated that the current spatial patterns of MHC variation in Blakiston's fish owl populations have been shaped by loss of variation due to the decline and fragmentation of populations, and that the short-term effects of genetic drift have counteracted the long-term effects of balancing selection.

The fall and rise of the Icelandic Arctic fox (Vulpes lagopus): a 50-year demographic study on a non-cyclic Arctic fox population.

PubMed

Unnsteinsdottir, E R; Hersteinsson, P; Pálsson, S; Angerbjörn, A

2016-08-01

In territorial species, observed density dependence is often manifest in lowered reproductive output at high population density where individuals have fewer resources or are forced to inhabit low-quality territories. The Arctic fox (Vulpes lagopus) in Iceland is territorial throughout the year and feeds mostly on birds, since lemmings are absent from the country. Thus, the population does not exhibit short-term population cycles that are evident in most of the species' geographical range. The population has, however, gone through a major long-term fluctuation in population size. Because of the stability in hunting effort and reliable hunting records since 1958, the total number of adult foxes killed annually can be used as an index of population size (N t ). An index of carrying capacity (K) from population growth data for five separate time blocks during 1958-2007 revealed considerable variation in K and allowed a novel definition of population density in terms of K, or N t /K. Correlation analysis suggested that the reproductive rate was largely determined by the proportion of territorial foxes in the population. Variation in litter size and cub mortality was, on the other hand, related to climatic variation. Thus, Arctic foxes in Iceland engage in typical contest competition but can adapt their territory sizes in response to both temporal and spatial variation in carrying capacity, resulting in surprisingly little variation in litter size.

Geographic variation in lumbar diskectomy: a protocol for evaluation.

PubMed

Barron, M; Kazandjian, V A

1992-03-01

In 1989 the Maryland Hospital Association (MHA) began developing a protocol related to lumbar diskectomy, a procedure with widely reported geographic variation in its use. The MHA's Laminectomy Advisory Committee drafted three criteria for performance of lumbar diskectomy and also developed a data-collection instrument with which the eight hospitals participating in a pilot study could abstract the necessary data from medical records. Both individual hospital and aggregate results showed wide variation in compliance with the criteria. These findings suggest research and development activities such as refinement of the data-collection instrument, use of the protocol for bench-marking, further investigation of clinical and other determinants of rate variation, and study of the effect of new diagnostic technology on utilization rates for this procedure.

Bridging the Gap between Theory and Practice in Integrated Care: The Case of the Diabetic Foot Pathway in Tuscany

PubMed Central

Bini, Barbara; Ruggieri, Tommaso Grillo; Piaggesi, Alberto; Ricci, Lucia

2016-01-01

Introduction and Background: As diabetic foot (DF) care benefits from integration, monitoring geographic variations in lower limb Major Amputation rate enables to highlight potential lack of Integrated Care. In Tuscany (Italy), these DF outcomes were good on average but they varied within the region. In order to stimulate an improvement process towards integration, the project aimed to shift health professionals’ focus on the geographic variation issue, promote the Population Medicine approach, and engage professionals in a community of practice. Method: Three strategies were thus carried out: the use of a transparent performance evaluation system based on benchmarking; the use of patient stories and benchmarking analyses on outcomes, service utilization and costs that cross-checked delivery- and population-based perspectives; the establishment of a stable community of professionals to discuss data and practices. Results: The project enabled professionals to shift their focus on geographic variation and to a joint accountability on outcomes and costs for the entire patient pathways. Organizational best practices and gaps in integration were identified and improvement actions towards Integrated Care were implemented. Conclusion and Discussion: For the specific category of care pathways whose geographic variation is related to a lack of Integrated Care, a comprehensive strategy to improve outcomes and reduce equity gaps by diffusing integration should be carried out. PMID:29042842

Geographic Variation of Chronic Kidney Disease Prevalence: Correlation with the Incidence of Renal Cell Carcinoma or Urothelial Carcinoma?

PubMed Central

Yap, Yit-Sheung; Chuang, Kai-Wen; Chiang, Chun-Ju; Chuang, Hung-Yi

2015-01-01

Background. The aim of this study is to evaluate whether geographic variations in the prevalence of late-stage chronic kidney disease (CKD) exist and are associated with incidence rates of renal cell carcinoma (RCC), upper tract urothelial carcinoma (UTUC), or lower tract urothelial carcinoma (LTUC). Methods. Prevalence rates of late-stage CKD for 366 townships (n > 30) in Taiwan were calculated for 1,518,241 and 1,645,151 subjects aged 40 years or older in years 2010 and 2009, respectively. Late-stage CKD prevalence in year 2010 was used as a training set and its age-adjusted standardized morbidity rates (ASMR) were divided into three groups as defined <1.76%, 1.76% ≤ ASMR < 2.64%, and ≥2.64%, respectively. Year 2009, defined as the validation set, was used to validate the results. Results. The ASMR of late-stage CKD in years 2010 and 2009 were 1.76%, and 2.09%, respectively. Geographic variations were observed, with notably higher rates of disease in areas of the central, southwestern mountainside, and southeastern seaboard. There were no significant differences among different combined risk groups of RCC, UTUC, and LTUC incidence. Conclusion. The substantial geographic variations in the prevalence of late-stage CKD exist, but are not correlated with RCC, UTUC, or LTUC incidence. PMID:26605329

Epidemiology of Mental Retardation.

ERIC Educational Resources Information Center

Heber, Rick

Prevalence data on mental retardation is presented including international estimates on general prevalence, age directions, geographical variations within the United States, racial and ethnic variations, economic class distributions, family variations, and population distribution in institutions. Statistics are also provided in areas of specific…

Where You Live Matters: Localising Environmental Impacts on Health, Nutrition and Poverty in Cambodia Using Small Area Estimation Techniques

NASA Astrophysics Data System (ADS)

Nilsen, K.; van Soesbergen, A.; Matthews, Z.

2016-12-01

Socioeconomic development depends on local environments. However, the scientific evidence quantifying the impact of environmental factors on health, nutrition and poverty at subnational levels is limited. This is because socioeconomic indicators are derived from sample surveys representative only at aggregate levels compared to environmental variables mostly available in high-resolution grids. Cambodia was selected because of its commitment to development in the context of a rapidly deteriorating environment. Having made considerable progress since 2005, access to health services is limited, a quarter of the population is still poor and 40% rural children are malnourished. Cambodia is also facing considerable environmental challenges including high deforestation rates, land degradation and natural hazards. Addressing existing gaps in the knowledge of environmental impacts on health and livelihoods, this study applies small area estimation (SAE) to quantify health, nutritional and poverty outcomes in the context of local environments. SAE produces reliable subnational estimates of socioeconomic outcomes available only from sample surveys by combining them with information from auxiliary sources (census). A model is used to explain common trades across areas and a random effect structure is applied to explain the observed extra heterogeneity. SAE models predicting health, nutrition and poverty outcomes excluding and including contextual environmental variables on natural hazards vulnerability, forest cover, climate, and agricultural production are compared. Results are mapped at regional and district levels to spatially assess the impacts of environmental variation on the outcomes. Inter and intra-regional inequalities are also estimated to examine the efficacy of health/socioeconomic policy targeting based on geographic location. Preliminary results suggest that localised environmental factors have considerable impacts on the indicators estimated and should therefore not be ignored. While there are large regional differences, pockets of malnutrition, poverty and inequitable health outcomes within regions are identified. The inequality decomposition shows under and over-coverage of geographical targeting when environmental factors are taken into account.

Prevalence and Geographic Variations of Polypharmacy Among West Virginia Medicaid Beneficiaries.

PubMed

Feng, Xue; Tan, Xi; Riley, Brittany; Zheng, Tianyu; Bias, Thomas K; Becker, James B; Sambamoorthi, Usha

2017-11-01

West Virginia (WV) residents are at high risk for polypharmacy given its considerable chronic disease burdens. To evaluate the prevalence, correlates, outcomes, and geographic variations of polypharmacy among WV Medicaid beneficiaries. In this cross-sectional study, we analyzed 2009-2010 WV Medicaid fee-for-service (FFS) claims data for adults aged 18-64 (N=37,570). We defined polypharmacy as simultaneous use of drugs from five or more different drug classes on a daily basis for at least 60 consecutive days in one year. Multilevel logistic regression was used to explore the individual- and county-level factors associated with polypharmacy. Its relationship with healthcare utilization was assessed using negative binomial regression and logistic regression. The univariate local indicators of spatial association method was applied to explore spatial patterns of polypharmacy in WV. The prevalence of polypharmacy among WV Medicaid beneficiaries was 44.6%. High-high clusters of polypharmacy were identified in southern WV, indicating counties with above-average prevalence surrounded by counties with above-average prevalence. Polypharmacy was associated with being older, female, eligible for Medicaid due to cash assistance or medical eligibility, having any chronic conditions or more chronic conditions, and living in a county with lower levels of education. Polypharmacy was associated with more hospitalizations, emergency department visits, and outpatient visits, as well as higher non-drug medical expenditures. Polypharmacy was prevalent among WV Medicaid beneficiaries and was associated with substantial healthcare utilization and expenditures. The clustering of high prevalence of polypharmacy in southern WV may suggest targeted strategies to reduce polypharmacy burden in these areas.

Geographic variation in the Pine Barrens Treefrog (Hyla andersonii): concordance of genetic, morphometric and acoustic signal data.

PubMed

Warwick, Alexa R; Travis, Joseph; Lemmon, Emily Moriarty

2015-07-01

Delimiting species is important to every subfield in biology. Templeton's cohesion species concept uses genetic and ecological exchangeability to identify sets of populations that ought to be considered as the same species, and the lack of exchangeability helps determine which populations can be grouped as evolutionarily significant units (ESU) in conservation science. However, previous work assessing genetic and ecological interchangeability among populations has been limited in scope. Here, we provide a method for assessing exchangeability that incorporates multiple, independent lines of multivariate evidence in genetic, behavioural and morphological data. We use this approach to assess exchangeability across three disjunct groups of populations of the Pine Barrens Treefrog (Hyla andersonii) from the eastern United States. This species is considered threatened by each state in which it occurs and conservation management of this taxon requires a clearer understanding of how populations in these three regions may differ from one another. We find a strikingly concordant pattern in which the first axis of variation for each of the three types of data distinguishes populations along a latitudinal gradient and the second axis distinguishes the set of populations occurring in the Carolinas from those occurring in the New Jersey and Florida/Alabama regions. We know of no comparable data set that displays such concordance among different types of data across so large a geographic range. The overlap in trait values (i.e. exchangeability) between neighbouring regions, however, is substantial in all three types of data, which supports continued consideration of this taxon as a single species. © 2015 John Wiley & Sons Ltd.

The weekend effect alters the procurement and discard rates of deceased donor kidneys in the United States

PubMed Central

Mohan, Sumit; Foley, Karl; Chiles, Mariana C; Dube, Geoffrey K; Patzer, Rachel E; Pastan, Stephen; Crew, R John; Cohen, David; Ratner, Lloyd

2016-01-01

Factors contributing to the high rate of discard among deceased donor kidneys remain poorly understood and the influence of resource limitations of weekends on kidney transplantation is unknown. To quantify this we used data from the Scientific Registry of Transplant Recipients and assembled a retrospective cohort of 181,799 deceased donor kidneys recovered for transplantation from 2000-2013. We identified the impact of the day of the week on the procurement and subsequent utilization or discard of deceased donor kidneys in the United States, as well as report the geographic variation on the impact of weekends on transplantation. Compared to weekday kidneys, organs procured on weekends were significantly more likely to be discarded than transplanted (odds ratio: 1.16; 95% confidence interval 1.13 – 1.19), even after adjusting for organ quality (adjusted odds ratio: 1.13; 95% confidence interval 1.10 – 1.17). Weekend discards were of a significantly higher quality than weekday discards (kidney donor profile index: 76.5 vs 77.3%). Considerable geographic variation was noted in the proportion of transplants that occurred over the weekend. Kidneys available for transplant over the weekend were significantly more likely to be used at larger transplant centers, be shared without payback, and experienced shorter cold ischemia times. Thus, factors other than kidney quality are contributing to the discard of deceased donor kidneys, particularly during weekends. Policy prescriptions, administrative or organizational solutions within transplant programs may potentially mitigate against the recent increase in kidney discards. PMID:27182001

Comparative genetic structure between Sedum ussuriense and S. kamtschaticum (Crassulaceae), two stonecrops co-occurring on rocky cliffs.

PubMed

Chung, Mi Yoon; López-Pujol, Jordi; Chung, Myong Gi

2014-06-01

• Premise of the study: Geographic isolation due to discontinuities of suitable habitat may have significant effects on the genetic structure of plant populations. Even within a few kilometers, physical barriers to gene flow may lead to considerable genetic differentiation among populations.• Methods: Sedum ussuriense is a boreal species that in Korea occurs only in four valleys separated by mountain ranges in Juwangsan National Park and its vicinity (a range of ∼15 km). Its congener S. kamtschaticum, by contrast, co-occurs in the four valleys but also on the intervening mountains. Using 12 allozyme loci, we comparatively assessed genetic variability and structure in 12 population pairs of the two stonecrops.• Key results: While we found high and comparable levels of within-population genetic variation for the two species, among-population divergence was significantly higher in S. ussuriense (F ST = 0.261 vs. F ST = 0.165). Sedum ussuriense also showed a much higher percentage of among-valley variation (19%) than S. kamtschaticum (4%).• Conclusions: High levels of genetic diversity in the two Sedum species are consistent with the previous hypothesis that mountains of the Korean Peninsula served as glacial refugia for many boreal species. Given that the two congeners have similar life-history traits, the lower among-population differentiation in S. kamtschaticum is attributable to its higher abundance and more continuous distribution in the study area. This study confirms the central role of geographic isolation in the genetic structure of plant species even at very small scales. © 2014 Botanical Society of America, Inc.

Geographic patterns of genetic variation and conservation consequences in three South American rodents.

PubMed

Miranda, Gustavo B; Andrades-Miranda, Jaqueline; Oliveira, Luiz F B; Langguth, Alfredo; Mattevi, Margarete S

2007-12-01

In this study, the geographic patterns of genetic variation of three rodent species belonging to the tribe Oryzomyini were investigated using the mitochondrial cytochrome b and nuclear IRBP genes in biomes that are undergoing degradation processes to a greater or lesser degree. The samples are from 25 collecting localities distributed throughout the Amazon, Cerrado, Atlantic Forest, and Pampa biomes. The results show that the three species have a population and geographic structure, besides being in demographic equilibrium. The phylogenetic analyses performed on Euryoryzomys russatus and Hylaeamys megacephalus showed these specimens grouped in three distinct clades forming geographic gradients (North-South direction in H. megacephalus). Intraspecific genetic divergence was higher in H. megacephalus (4.53%), followed by E. russatus (1.79%), and lowest in Sooretamys angouya (0.88%). The results obtained indicate that, necessarily, the management strategies to preserve genetic diversity should be different for each species, since each of them presented specific population parameters.

The population genomic signature of environmental selection in the widespread insect-pollinated tree species Frangula alnus at different geographical scales

PubMed Central

De Kort, H; Vandepitte, K; Mergeay, J; Mijnsbrugge, K V; Honnay, O

2015-01-01

The evaluation of the molecular signatures of selection in species lacking an available closely related reference genome remains challenging, yet it may provide valuable fundamental insights into the capacity of populations to respond to environmental cues. We screened 25 native populations of the tree species Frangula alnus subsp. alnus (Rhamnaceae), covering three different geographical scales, for 183 annotated single-nucleotide polymorphisms (SNPs). Standard population genomic outlier screens were combined with individual-based and multivariate landscape genomic approaches to examine the strength of selection relative to neutral processes in shaping genomic variation, and to identify the main environmental agents driving selection. Our results demonstrate a more distinct signature of selection with increasing geographical distance, as indicated by the proportion of SNPs (i) showing exceptional patterns of genetic diversity and differentiation (outliers) and (ii) associated with climate. Both temperature and precipitation have an important role as selective agents in shaping adaptive genomic differentiation in F. alnus subsp. alnus, although their relative importance differed among spatial scales. At the ‘intermediate' and ‘regional' scales, where limited genetic clustering and high population diversity were observed, some indications of natural selection may suggest a major role for gene flow in safeguarding adaptability. High genetic diversity at loci under selection in particular, indicated considerable adaptive potential, which may nevertheless be compromised by the combined effects of climate change and habitat fragmentation. PMID:25944466

Trends in child immunization across geographical regions in India: focus on urban-rural and gender differentials.

PubMed

Singh, Prashant Kumar

2013-01-01

Although child immunization is regarded as a highly cost-effective lifesaver, about fifty percent of the eligible children aged 12-23 months in India are without essential immunization coverage. Despite several programmatic initiatives, urban-rural and gender difference in child immunization pose an intimidating challenge to India's public health agenda. This study assesses the urban-rural and gender difference in child immunization coverage during 1992-2006 across six major geographical regions in India. Three rounds of the National Family Health Survey (NFHS) conducted during 1992-93, 1998-99 and 2005-06 were analyzed. Bivariate analyses, urban-rural and gender inequality ratios, and the multivariate-pooled logistic regression model were applied to examine the trends and patterns of inequalities over time. The analysis of change over one and half decades (1992-2006) shows considerable variations in child immunization coverage across six geographical regions in India. Despite a decline in urban-rural and gender differences over time, children residing in rural areas and girls remained disadvantaged. Moreover, northeast, west and south regions, which had the lowest gender inequality in 1992 observed an increase in gender difference over time. Similarly, urban-rural inequality increased in the west region during 1992-2006. This study suggests periodic evaluation of the health care system is vital to assess the between and within group difference beyond average improvement. It is essential to integrate strong immunization systems with broad health systems and coordinate with other primary health care delivery programs to augment immunization coverage.

Regional differences in low birth weight in Spain: biological, demographic and socioeconomic variables.

PubMed

Fuster, Vicente; Zuluaga, Pilar; Colantonio, S E; Román-Busto, J

2015-01-01

The geographic and demographic dimensions of Spain, in terms of surface and number of inhabitants, and its heterogeneous socioeconomic development offer an adequate opportunity to study the provincial differences in birth weight from 1996 to 2010, focusing on possible factors determining the relative frequency of low birth weight. The study analysed geographic differences with regard to biological, demographic and socioeconomic factors that interfere with the female reproductive pattern. The variables considered here were: birth order, proportion of premature deliveries, mother's age, multiparity, mother's country of origin and professional qualifications. Two periods (1996-2000 and 2006-2010) were compared by means of principal components analysis. An increase in the relative frequency of deliveries weighing less than 2500 g occurred in most of the 52 geographic units studied, differences being significant in 42. Only in five cases was there a non-significant reduction in the proportion of low weight births. The first component after principal component analysis indicated that low birth weight was positively related to maternal age and to multiple deliveries, and negatively to the mother's low professional qualification. The second component related positively to the incidence of premature deliveries and to non-Spanish status and negatively in the case of primiparous mothers. The progressive increase in low birth weight incidence observed in Spain from 1996 onwards has occurred with considerable variation in each province. In part, this diversity can be attributed to the unequal reproductive patterns of immigrant mothers.

Predictive models and spatial variations of vital capacity in healthy people from 6 to 84 years old in China based on geographical factors.

PubMed

He, Jinwei; Ge, Miao; Wang, Congxia; Jiang, Naigui; Zhang, Mingxin; Yun, Pujun

2014-07-01

The aim of this study was to provide a scientific basic for a unified standard of the reference value of vital capacity (VC) of healthy subjects from 6 and 84 years old in China. The normal reference value of VC was correlated to seven geographical factors, including altitude (X1), annual duration of sunshine (X2), annual mean air temperature (X3), annual mean relative humidity (X4), annual precipitation amount (X5), annual air temperature range (X6) and annual mean wind speed (X7). Predictive models were established by five different linear and nonlinear methods. The best models were selected by t-test. The geographical distribution map of VC in different age groups can be interpolated by Kriging's method using ArcGIS software. It was found that the correlation of VC and geographical factors in China was quite significant, especially for both males and females aged from 6 to 45. The best models were built for different age groups. The geographical distribution map shows the spatial variations of VC in China precisely. The VC of healthy subjects can be simulated by the best model or acquired from the geographical distribution map provided the geographical factors for that city or county of China are known.

Geographic Variation of Amyotrophic Lateral Sclerosis Incidence in New Jersey, 2009–2011

PubMed Central

Henry, Kevin A.; Fagliano, Jerald; Jordan, Heather M.; Rechtman, Lindsay; Kaye, Wendy E.

2015-01-01

Few analyses in the United States have examined geographic variation and socioeconomic disparities in amyotrophic lateral sclerosis (ALS) incidence, because of lack of population-based incidence data. In this analysis, we used population-based ALS data to identify whether ALS incidence clusters geographically and to determine whether ALS risk varies by area-based socioeconomic status (SES). This study included 493 incident ALS cases diagnosed (via El Escorial criteria) in New Jersey between 2009 and 2011. Geographic variation and clustering of ALS incidence was assessed using a spatial scan statistic and Bayesian geoadditive models. Poisson regression was used to estimate the associations between ALS risk and SES based on census-tract median income while controlling for age, sex, and race. ALS incidence varied across and within counties, but there were no statistically significant geographic clusters. SES was associated with ALS incidence. After adjustment for age, sex, and race, the relative risk of ALS was significantly higher (relative risk (RR) = 1.37, 95% confidence interval (CI): 1.02, 1.82) in the highest income quartile than in the lowest. The relative risk of ALS was significantly lower among blacks (RR = 0.57, 95% CI: 0.39, 0.83) and Asians (RR = 0.63, 95% CI: 0.41, 0.97) than among whites. Our findings suggest that ALS incidence in New Jersey appears to be associated with SES and race. PMID:26041711

Geographical variation in the incidence of childhood leukaemia in Manitoba.

PubMed

Torabi, Mahmoud; Singh, Harminder; Galloway, Katie; Israels, Sara J

2015-11-01

Identification of geographical areas and ecological factors associated with higher incidence of childhood leukaemias can direct further study for preventable factors and location of health services to manage such individuals. The aim of this study was to describe the geographical variation and the socio-demographic factors associated with childhood leukaemia in Manitoba. Information on childhood leukaemia incidence between 1992 and 2008 was obtained from the Canadian Cancer Registry and the socio-demographic characteristics for the area of residence from the 2006 Canadian Census. Bayesian spatial Poisson mixed models were used to describe the geographical variation of childhood leukaemia and to determine the association between childhood leukaemia and socio-demographic factors. The south-eastern part of the province had a higher incidence of childhood leukaemia than other parts of the province. In the age and sex-adjusted Poisson regression models, areas with higher proportions of visible minorities and immigrant residents had higher childhood leukaemia incidence rate ratios. In the saturated Poisson regression model, the childhood leukaemia rates were higher in areas with higher proportions of immigrant residents. Unemployment rates were not a significant factor in leukaemia incidence. In Manitoba, areas with higher proportions of immigrants experience higher incidence rates of childhood leukaemia. We have identified geographical areas with higher incidence, which require further study and attention. © 2015 The Authors. Journal of Paediatrics and Child Health © 2015 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Variation in the costs of delivering routine immunization services in Peru.

PubMed

Walker, D; Mosqueira, N R; Penny, M E; Lanata, C F; Clark, A D; Sanderson, C F B; Fox-Rushby, J A

2004-09-01

Estimates of vaccination costs usually provide only point estimates at national level with no information on cost variation. In practice, however, such information is necessary for programme managers. This paper presents information on the variations in costs of delivering routine immunization services in three diverse districts of Peru: Ayacucho (a mountainous area), San Martin (a jungle area) and Lima (a coastal area). We consider the impact of variability on predictions of cost and reflect on the likely impact on expected cost-effectiveness ratios, policy decisions and future research practice. All costs are in 2002 prices in US dollars and include the costs of providing vaccination services incurred by 19 government health facilities during the January-December 2002 financial year. Vaccine wastage rates have been estimated using stock records. The cost per fully vaccinated child ranged from 16.63-24.52 U.S. Dollars in Ayacucho, 21.79-36.69 U.S. Dollars in San Martin and 9.58-20.31 U.S. Dollars in Lima. The volume of vaccines administered and wastage rates are determinants of the variation in costs of delivering routine immunization services. This study shows there is considerable variation in the costs of providing vaccines across geographical regions and different types of facilities. Information on how costs vary can be used as a basis from which to generalize to other settings and provide more accurate estimates for decision-makers who do not have disaggregated data on local costs. Future studies should include sufficiently large sample sizes and ensure that regions are carefully selected in order to maximize the interpretation of cost variation.

Time Trends and Geographical Variation in Prescribing of Drugs for Diabetes in England 1998-2017.

PubMed

Curtis, Helen J; Dennis, John M; Shields, Beverley M; Walker, Alex J; Bacon, Seb; Hattersley, Andrew T; Jones, Angus G; Goldacre, Ben

2018-05-07

UK guidelines for type II diabetes leave the choice of glucose lowering therapies after metformin largely to prescribers. They vary greatly in cost, and comparative effectiveness data is lacking. We set out to measure the variation in prescribing of these second-line non-insulin diabetes drugs. We evaluated time trends 1998-2016, using England's publicly available prescribing datasets, and stratified by the order prescribed to patients using the Clinical Practice Research Datalink (CPRD). We calculated the proportion of each class of diabetes drug as a percentage of the total per year. We evaluated geographical variation in prescribing using general practice-level data for the latest 12-months (to August 2017), with aggregation to Clinical Commissioning Groups (CCGs). We calculated percentiles, ranges and plotted maps. Prescribing of therapy after metformin is changing rapidly. DPP4-inhibitor use has increased markedly, now the most common second-line drug (43% prescriptions in 2016). Use of SGLT-2 inhibitors also increased rapidly (14% new second-line, 27% new third-line prescriptions in 2016). There is wide geographical variation in choice of therapies and average spend per patient. In contrast, metformin is consistently used first-line in accordance with guidelines. In England there is extensive geographical variation in the prescribing of diabetes drugs after metformin, and increasing use of higher-cost DPP4-inhibitors and SGLT-2 inhibitors over low-cost sulfonylureas. Our findings strongly support the case for comparative effectiveness trials of current diabetes drugs. This article is protected by copyright. All rights reserved.

Geographical Variation and Social Work Students' Job Intentions in China: A Geographic Information Systems Approach.

PubMed

Wang, Yean; Guo, Yingqi; Zeng, Shouchui

2018-04-01

Social work education in China is undergoing far-reaching development. However, an important issue, low professional commitment, has been identified. Why do social work graduates-especially master's level graduates-take jobs unrelated to social work? To answer this question, it is important to take into account that the professionalization of social work is happening unevenly across China as a result of uneven social and economic development. Models used in past research do not consider the possibility that the low intention for social work jobs and its potential predictors may vary across regions. To address this problem, Geographic Information Systems software is being adopted to explore the varying degrees of social work graduates' job intention, its predictors across China, and the association between job intention and predictors at both national and regional levels. Authors of this study found substantial geographic variation in predictors of social work graduates' job intention across regions. Their findings also suggest some heterogeneity in the association between job intention and specific correlates that would be masked in the traditional nationwide model. Policymakers aiming to improve the job intention of social work graduates should consider regional variation as part of their approach.

Morphometric Variation of the Aedes albifasciatus (Diptera: Culicidae) Wings in Three Populations From Different Ecoregions of Argentina.

PubMed

Garzón, Maximiliano J; Schweigmann, Nicolás

2018-06-23

Shape variability among individuals is important to understand some ecological relationships, since it provides the nexus between the genotype and the environment. Geometric morphometrics based on generalized procrustes analysis was applied on 17 landmarks of the wings of Aedes albifasciatus (Macquart 1838) (Diptera: Culicidae) females collected from three ecoregions of Argentina (Delta and islands of the Paraná River, Pampa, and Patagonian steppe). This methodology was used to discriminate the shapes of individuals belonging to different regions. The population of the Patagonian steppe, which was the most geographically distant, showed the most dissimilar shape. Different local variations in wing shape could have been selected according to the environmental characteristics and maintained by geographic isolation. The individuals of the two ecoregions closest to each other (Delta and islands of the Paraná River and Pampa) showed differences in shape that can be explained by a lower gene flow due to the effect of geographic isolation (by the Paraná River) and the limited dispersive capacity of Ae. albifasciatus. The results allow concluding that both environmental diversity and geographic barriers could contribute to local variations in wing shape.

Socioeconomic Status Accounts for Rapidly Increasing Geographic Variation in the Incidence of Poor Fetal Growth

PubMed Central

Ball, Stephen J.; Jacoby, Peter; Zubrick, Stephen R.

2013-01-01

Fetal growth is an important risk factor for infant morbidity and mortality. In turn, socioeconomic status is a key predictor of fetal growth; however, other sociodemographic factors and environmental effects may also be important. This study modelled geographic variation in poor fetal growth after accounting for socioeconomic status, with a fixed effect for socioeconomic status and a combination of spatially-correlated and spatially-uncorrelated random effects. The dataset comprised 88,246 liveborn singletons, aggregated within suburbs in Perth, Western Australia. Low socioeconomic status was strongly associated with an increased risk of poor fetal growth. An increase in geographic variation of poor fetal growth from 1999–2001 (interquartile odds ratio among suburbs = 1.20) to 2004–2006 (interquartile odds ratio = 1.40) indicated a widening risk disparity by socioeconomic status. Low levels of residual spatial patterns strengthen the case for targeting policies and practices in areas of low socioeconomic status for improved outcomes. This study indicates an alarming increase in geographic inequalities in poor fetal growth in Perth which warrants further research into the specific aspects of socioeconomic status that act as risk factors. PMID:23799513

Life history variation among geographically close populations of the toad-headed lizard (Phrynocephalus przewalskii): Exploring environmental and physiological associations

NASA Astrophysics Data System (ADS)

Zeng, Zhi-Gao; Zhao, Jia-Ming; Sun, Bao-Jun

2013-08-01

Geographic variation in life history traits has been extensively studied along latitudinal and altitudinal clines, but life history variation among geographically close populations has received much less attention. We collected gravid female toad-headed lizards (Phrynocephalus przewalskii) and environmental data from three localities (Alxa Zuoqi, Alxa Youqi, and Shandan) across the Gobi desert in China, to examine among-population differences in reproductive strategies. The precipitation was significantly lower in Alxa Youqi than Alxa Zouqi and Shandan. Food availability was highest in Shandan, lowest in Alxa Zuoqi, with Alxa Youqi in between. Females from Shandan population were larger and produced more and larger eggs than their counterparts from the other two populations. Incubation period also differed among the populations, with the lowest incubation period in Alxa Youqi population, and the longest incubation period in Alxa Zuoqi population. Our data on the physiological mechanisms of incubation period indicated that the shortened incubation period in Alxa Youqi population was due to advanced embryogenesis completed prior to oviposition rather than higher embryonic heart rates during incubation. Therefore, our data support the hypothesis that geographically close populations can show different reproductive strategies if environmental factors vary among these populations.

Does geography or ecology best explain 'cultural' variation among chimpanzee communities?

PubMed

Kamilar, Jason M; Marshack, Joshua L

2012-02-01

Much attention has been paid to geographic variation in chimpanzee behavior, but few studies have applied quantitative techniques to explain this variation. Here, we apply methods typically utilized in macroecology to explain variation in the putative cultural traits of chimpanzees. We analyzed published data containing 39 behavioral traits from nine chimpanzee communities. We used a canonical correspondence analysis to examine the relative importance of environmental characteristics and geography, which may be a proxy for inter-community gene flow and/or social transmission, for explaining geographic variation in chimpanzee behavior. We found that geography, and longitude in particular, was the best predictor of behavioral variation. Chimpanzee communities in close longitudinal proximity to each other exhibit similar behavioral repertoires, independent of local ecological factors. No ecological variables were significantly related to behavioral variation. These results support the idea that inter-community dispersal patterns have played a major role in structuring behavioral variation. We cannot be certain whether behavioral variation has a genetic basis, is the result of innovation and diffusion, or a combination of the two. Copyright © 2011 Elsevier Ltd. All rights reserved.

Geographic variation in advertisement calls of a Microhylid frog - testing the role of drift and ecology.

PubMed

Lee, Ko-Huan; Shaner, Pei-Jen L; Lin, Yen-Po; Lin, Si-Min

2016-05-01

Acoustic signals for mating are important traits that could drive population differentiation and speciation. Ecology may play a role in acoustic divergence through direct selection (e.g., local adaptation to abiotic environment), constraint of correlated traits (e.g., acoustic traits linked to another trait under selection), and/or interspecific competition (e.g., character displacement). However, genetic drift alone can also drive acoustic divergence. It is not always easy to differentiate the role of ecology versus drift in acoustic divergence. In this study, we tested the role of ecology and drift in shaping geographic variation in the advertisement calls of Microhyla fissipes. We examined three predictions based on ecological processes: (1) the correlation between temperature and call properties across M. fissipes populations; (2) the correlation between call properties and body size across M. fissipes populations; and (3) reproductive character displacement (RCD) in call properties between M. fissipes populations that are sympatric with and allopatric to a congener M. heymonsi. To test genetic drift, we examined correlations among call divergence, geographic distance, and genetic distance across M. fissipes populations. We recorded the advertisement calls from 11 populations of M. fissipes in Taiwan, five of which are sympatrically distributed with M. heymonsi. We found geographic variation in both temporal and spectral properties of the advertisement calls of M. fissipes. However, the call properties were not correlated with local temperature or the callers' body size. Furthermore, we did not detect RCD. By contrast, call divergence, geographic distance, and genetic distance between M. fissipes populations were all positively correlated. The comparisons between phenotypic Q st (P st) and F st values did not show significant differences, suggesting a role of drift. We concluded that genetic drift, rather than ecological processes, is the more likely driver for the geographic variation in the advertisement calls of M. fissipes.

Temporal Trends in Geographical Variation in Breast Cancer Mortality in China, 1973–2005: An Analysis of Nationwide Surveys on Cause of Death

PubMed Central

Xia, Changfa; Kahn, Clare; Wang, Jinfeng; Liao, Yilan; Chen, Wanqing; Yu, Xue Qin

2016-01-01

To describe geographical variation in breast cancer mortality over time, we analysed breast cancer mortality data from three retrospective national surveys on causes of death in recent decades in China. We first calculated the age-standardized mortality rate (ASMR) for each of the 31 provinces in mainland China stratified by survey period (1973–1975, 1990–1992 and 2004–2005). To test whether the geographical variation in breast cancer mortality changed over time, we then estimated the rate ratio (RR) for the aggregated data for seven regions and three economic zones using generalized linear models. Finally, we examined the correlation between mortality rate and several macro-economic measures at the provincial level. We found that the overall ASMR increased from 2.98 per 100,000 in 1973–1975 to 3.08 per 100,000 in 1990–1992, and to 3.85 per 100,000 in 2004–2005. Geographical variation in breast cancer mortality also increased significantly over time at the regional level (p = 0.002) but not at the economic zone (p = 0.089) level, with RR being generally lower for Western China (Northwest and Southwest) and higher in Northeast China over the three survey periods. These temporal and spatial trends in breast cancer mortality were found to be correlated with per capita gross domestic product, number of hospitals and health centres’ beds per 10,000 population and number of practicing doctors per 10,000 population, and average number of live births for women aged 15–64. It may be necessary to target public health policies in China to address the widening geographic variation in breast cancer mortality, and to take steps to ensure that the ease of access and the quality of cancer care across the country is improved for all residents. PMID:27690073

Temporal Trends in Geographical Variation in Breast Cancer Mortality in China, 1973-2005: An Analysis of Nationwide Surveys on Cause of Death.

PubMed

Xia, Changfa; Kahn, Clare; Wang, Jinfeng; Liao, Yilan; Chen, Wanqing; Yu, Xue Qin

2016-09-28

To describe geographical variation in breast cancer mortality over time, we analysed breast cancer mortality data from three retrospective national surveys on causes of death in recent decades in China. We first calculated the age-standardized mortality rate (ASMR) for each of the 31 provinces in mainland China stratified by survey period (1973-1975, 1990-1992 and 2004-2005). To test whether the geographical variation in breast cancer mortality changed over time, we then estimated the rate ratio (RR) for the aggregated data for seven regions and three economic zones using generalized linear models. Finally, we examined the correlation between mortality rate and several macro-economic measures at the provincial level. We found that the overall ASMR increased from 2.98 per 100,000 in 1973-1975 to 3.08 per 100,000 in 1990-1992, and to 3.85 per 100,000 in 2004-2005. Geographical variation in breast cancer mortality also increased significantly over time at the regional level ( p = 0.002) but not at the economic zone ( p = 0.089) level, with RR being generally lower for Western China (Northwest and Southwest) and higher in Northeast China over the three survey periods. These temporal and spatial trends in breast cancer mortality were found to be correlated with per capita gross domestic product, number of hospitals and health centres' beds per 10,000 population and number of practicing doctors per 10,000 population, and average number of live births for women aged 15-64. It may be necessary to target public health policies in China to address the widening geographic variation in breast cancer mortality, and to take steps to ensure that the ease of access and the quality of cancer care across the country is improved for all residents.

Geographic variations of the bird-borne structural risk of West Nile virus circulation in Europe

PubMed Central

Durand, Benoit; Tran, Annelise; Balança, Gilles

2017-01-01

The structural risk of West Nile Disease results from the usual functioning of the socio-ecological system, which may favour the introduction of the pathogen, its circulation and the occurrence of disease cases. Its geographic variations result from the local interactions between three components: (i) reservoir hosts, (ii) vectors, both characterized by their diversity, abundance and competence, (iii) and the socio-economic context that impacts the exposure of human to infectious bites. We developed a model of bird-borne structural risk of West Nile Virus (WNV) circulation in Europe, and analysed the association between the geographic variations of this risk and the occurrence of WND human cases between 2002 and 2014. A meta-analysis of WNV serosurveys conducted in wild bird populations was performed to elaborate a model of WNV seropositivity in European bird species, considered a proxy for bird exposure to WNV. Several eco-ethological traits of bird species were linked to seropositivity and the statistical model adequately fitted species-specific seropositivity data (area under the ROC curve: 0.85). Combined with species distribution maps, this model allowed deriving geographic variations of the bird-borne structural risk of WNV circulation. The association between this risk, and the occurrence of WND human cases across the European Union was assessed. Geographic risk variations of bird-borne structural risk allowed predicting WND case occurrence in administrative districts of the EU with a sensitivity of 86% (95% CI: 0.79–0.92), and a specificity of 68% (95% CI: 0.66–0.71). Disentangling structural and conjectural health risks is important for public health managers as risk mitigation procedures differ according to risk type. The results obtained show promise for the prevention of WND in Europe. Combined with analyses of vector-borne structural risk, they should allow designing efficient and targeted prevention measures. PMID:29023472

Geographic variation in secondary fracture prevention after a hip fracture during 1999-2013: a UK study.

PubMed

Shah, A; Prieto-Alhambra, D; Hawley, S; Delmestri, A; Lippett, J; Cooper, C; Judge, A; Javaid, M K

2017-01-01

Fragility fractures of the hip have a major impact on the lives of patients and their families. This study highlights significant geographical variation in secondary fracture prevention with even the highest performing regions failing the majority of patients despite robust evidence supporting the benefits of diagnosis and treatment. The purpose of the study is to describe the geographic variation in anti-osteoporosis drug therapy prescriptions before and after a hip fracture during 1999-2013 in the UK. We used primary care data (Clinical Practice Research Datalink) to identify patients with a hip fracture and primary care prescriptions of any anti-osteoporosis drugs prior to the index hip fracture and up to 5 years after. Geographic variations in prescribing before and after availability of generic oral bisphosphonates were analysed. Multivariable logistic regression models were adjusted for gender, age and body mass index (BMI). Thirteen thousand sixty-nine patients (76 % female) diagnosed with a hip fracture during 1999-2013 were identified. Eleven per cent had any anti-osteoporosis drug prescription in the 6 months prior to the index hip fracture. In the 0-4 months following a hip fracture, 5 % of patients were prescribed anti-osteoporosis drugs in 1999, increasing to 51 % in 2011 and then decreasing to 39 % in 2013. The independent predictors (OR (95 % CI)) of treatment initiation included gender (male 0.42 (0.36-0.49)), BMI (0.98 per kg/m 2 increase (0.97-1.00)) and geographic region (1.29 (0.89-1.87) North East vs. 0.56 (0.43-0.73) South Central region). Geographic differences in prescribing persisted over the 5-year follow-up. If all patients were treated at the rate of the highest performing region, then nationally, an additional 3214 hip fracture patients would be initiated on therapy every year. Significant geographic differences exist in prescribing of anti-osteoporosis drugs after hip fracture despite adjustment for potential confounders. Further work examining differences in health care provision may inform strategies to improve secondary fracture prevention after hip fracture.

Geographic variation in the surgical management of lumbar spondylolisthesis: characterizing practice patterns and outcomes.

PubMed

Azad, Tej D; Vail, Daniel; O'Connell, Chloe; Han, Summer S; Veeravagu, Anand; Ratliff, John K

2018-05-07

The role of arthrodesis in the surgical management of lumbar spondylolisthesis remains controversial. We hypothesized that practice patterns and outcomes for this patient population may vary widely. To characterize geographic variation in surgical practices and outcomes for patients with lumbar spondylolisthesis. Retrospective analysis on a national longitudinal database between 2007 and 2014. We calculated arthrodesis rates, inpatient and long term costs, and key quality indicators (e.g. reoperation rates). Using linear and logistic regression models, we then calculated expected quality indicator values, adjusting for patient-level demographic factors, and compared these values to the observed values, to assess quality variation apart from differences in patient populations. We identified a cohort of 67,077 patients (60.7% female, mean age of 59.8 years (SD, 12.0) with lumbar spondylolisthesis who received either laminectomy or laminectomy with arthrodesis. The majority of patients received arthrodesis (91.8%). Actual rates of arthrodesis varied from 97.5% in South Dakota to 81.5% in Oregon. Geography remained a significant predictor of arthrodesis even after adjusting for demographic factors (p<0.001). Marked geographic variation was also observed in initial costs ($32,485 in Alabama to $78,433 in Colorado), two-year post-operative costs ($15,612 in Arkansas to $34,096 in New Jersey), length of hospital stay (2.6 days in Arkansas to 4.5 in Washington, D.C.), 30-day complication rates (9.5% in South Dakota to 22.4% in Maryland), 30-day readmission rates (2.5% in South Dakota to 13.6% in Connecticut), and reoperation rates (1.8% in Maine to 12.7% in Alabama). There is marked geographic variation in the rates of arthrodesis in treatment of spondylolisthesis within the United States. This variation remains pronounced after accounting for patient-level demographic differences. Costs of surgery and quality outcomes also vary widely. Further study is necessary to understand the drivers of this variation. Copyright © 2018. Published by Elsevier Inc.

Genetic Variation and Structure in Contrasting Geographic Distributions: Widespread Versus Restricted Black-Tailed Prairie Dogs (Subgenus Cynomys).

PubMed

Castellanos-Morales, Gabriela; Ortega, Jorge; Castillo-Gámez, Reyna A; Sackett, Loren C; Eguiarte, Luis E

2015-01-01

Species of restricted distribution are considered more vulnerable to extinction because of low levels of genetic variation relative to widespread taxa. Species of the subgenus Cynomys are an excellent system to compare genetic variation and degree of genetic structure in contrasting geographic distributions. We assessed levels of genetic variation, genetic structure, and genetic differentiation in widespread Cynomys ludovicianus and restricted C. mexicanus using 1997bp from the cytochrome b and control region (n = 223 C. ludovicianus; 77 C. mexicanus), and 10 nuclear microsatellite loci (n = 207 and 78, respectively). Genetic variation for both species was high, and genetic structure in the widespread species was higher than in the restricted species. C. mexicanus showed values of genetic variation, genetic structure, and genetic differentiation similar to C. ludovicianus at smaller geographic scales. Results suggest the presence of at least 2 historical refuges for C. ludovicianus and that the Sierra Madre Occidental represents a barrier to gene flow. Chihuahua and New Mexico possess high levels of genetic diversity and should be protected, while Sonora should be treated as an independent management unit. For C. mexicanus, connectivity among colonies is very important and habitat fragmentation and habitat loss should be mitigated to maintain gene flow. © The American Genetic Association 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Landscape genomics and pathway analysis to understand genetic adaptation of South African indigenous goat populations.

PubMed

Mdladla, K; Dzomba, E F; Muchadeyi, F C

2018-04-01

In Africa, extensively raised livestock populations in most smallholder farming communities are exposed to harsh and heterogeneous climatic conditions and disease pathogens that they adapt to in order to survive. Majority of these livestock species, including goats, are of non-descript and uncharacterized breeds and their response to natural selection presented by heterogeneous environments is still unresolved. This study investigated genetic diversity and its association with environmental and geographic conditions in 194 South African indigenous goats from different geographic locations genotyped on the Illumina goat SNP50K panel. Population structure analysis revealed a homogeneous genetic cluster of the Tankwa goats, restricted to the Northern Cape province. Overall, the Boer, Kalahari Red, and Savanna showed a wide geographic spread of shared genetic components, whereas the village ecotypes revealed a longitudinal distribution. The relative importance of environmental factors on genetic variation of goat populations was assessed using redundancy analysis (RDA). Climatic and geographic variables explained 22% of the total variation while climatic variables alone accounted for 17% of the diversity. Geographic variables solitarily explained 1% of the total variation. The first axis (Model I) of the RDA analysis revealed 329 outlier SNPs. Landscape genomic approaches of spatial analysis method (SAM) identified a total of 843 (1.75%) SNPs, while latent factor mixed models (LFMM) identified 714 (1.48%) SNPs significantly associated with environmental variables. Significant markers were within genes involved in biological functions potentially important for environmental adaptation. Overall, the study suggested environmental factors to have some effect in shaping the genetic variation of South African indigenous goat populations. Loci observed to be significant and under selection may be responsible for the adaption of the goat populations to local production systems.

Geographic Variation in the Use of Low-Acuity Pediatric Emergency Medical Services.

PubMed

Gregory, Emily F; Chamberlain, James M; Teach, Stephen J; Engstrom, Ryan; Mathison, David J

2017-02-01

The aim of this study was to examine geographic variation in pediatric low-acuity emergency medical services (EMS) use in Washington, DC. This cross-sectional analysis of low-acuity EMS transports evaluated arrivals at 2 emergency departments and included 93% of pediatric transports in Washington, DC, during the study period. Low-acuity classification was defined as a triage emergency severity index of 4 or 5 not resulting in transfer, admission, or death. Logistic regression compared low-acuity visits arriving via EMS with all other low-acuity visits. Home zip code represented geographic location. Covariates included patient age, sex, race/ethnicity, hour of emergency department arrival, and insurance status. There were 45,454 low-acuity visits among children aged 0 to 17 years. Of these, 3304 (7.3%) arrived via EMS. The mean age was 5.6 (±5.0) years. Most were African American (84.3%) and had Medicaid insurance (87.3%). Geographic variation predicted EMS use. Adjusted odds ratios (ORs) of using EMS varied from 1.11 to 2.54 when compared with the lowest EMS use zip code. Odds of EMS use were higher among those with public insurance (adjusted OR [adj OR], 1.71; 95% confidence interval [CI], 1.46-2.00) and those with evening and overnight arrivals (evening arrival, adj OR of 1.65 and 95% CI of 1.47-1.86; overnight arrival, adj OR of 2.98 and 95% CI of 2.43-3.65). After adjusting for known covariates, residential zip code was associated with low-acuity EMS activation, stressing the importance of geographic variation in EMS use. Providing alternate means of transportation, or targeted education to certain residential areas, may decrease unnecessary EMS activation.

Geographic Variation in Morbidity and Mortality of Cerebrovascular Diseases in Korea during 2011-2015.

PubMed

Lee, Juyeon; Bahk, Jinwook; Kim, Ikhan; Kim, Yeon-Yong; Yun, Sung-Cheol; Kang, Hee-Yeon; Lee, Jeehye; Park, Jong Heon; Shin, Soon-Ae; Khang, Young-Ho

2018-03-01

Little is known about within-country variation in morbidity and mortality of cerebrovascular diseases (CVDs). Geographic differences in CVD morbidity and mortality have yet to be properly examined. This study examined geographic variation in morbidity and mortality of CVD, neighborhood factors for CVD morbidity and mortality, and the association between CVD morbidity and mortality across the 245 local districts in Korea during 2011-2015. District-level health care utilization and mortality data were obtained to estimate age-standardized CVD morbidity and mortality. The bivariate Pearson correlation was used to examine the linear relationship between district-level CVD morbidity and mortality Z-scores. Simple linear regression and multivariate analyses were conducted to investigate the associations of area characteristics with CVD morbidity, mortality, and discrepancies between morbidity and mortality. Substantial variation was found in CVD morbidity and mortality across the country, with 1074.9 excess CVD inpatients and 73.8 excess CVD deaths per 100,000 between the districts with the lowest and highest CVD morbidity and mortality, respectively. Higher rates of CVD admissions and deaths were clustered in the noncapital regions. A moderate geographic correlation between CVD morbidity and mortality was found (Pearson correlation coefficient = .62 for both genders). Neighborhood level indicators for socioeconomic disadvantages, undersupply of health care resources, and unhealthy behaviors were positively associated with CVD morbidity and mortality and the relative standing of CVD mortality vis-à-vis morbidity. Policy actions targeting life-course socioeconomic conditions, equitable distribution of health care resources, and behavioral risk factors may help reduce geographic differences in CVD morbidity and mortality in Korea. Copyright © 2018 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Geographic variation in nasal cavity form among three human groups from the Japanese Archipelago: Ecogeographic and functional implications.

PubMed

Fukase, Hitoshi; Ito, Tsuyoshi; Ishida, Hajime

2016-05-01

Geographic variation in human nasal form has often been interpreted as a climatic adaptation, owing to the nasal air-conditioning function. The aim of this study was to further address morphofunctional issues of the nasal cavity, using three human groups from subarctic, temperate, and subtropical regions of the Japanese Archipelago: prehistoric Okhotsk, early-modern Honshu and Okinawa groups. Using three-dimensional coordinates of craniometric landmarks surrounding the nasal cavity, we compared linear measurements regarding nasal cavity form among the three groups and also conducted 3D geometric morphometrics. Both linear measurements and morphometric analyses corroborate the previously reported covariation pattern of nasal cavity shape with climate, where humans from a cold/dry climate tend to possess a relatively tall, narrow, and deep nasal cavity compared with those from a warm/humid environment. The northern Okhotsk group had overall larger cranial airways, which may be attributable to their large facial skeleton. However, the ratio of nasal/bimaxillary breadth was significantly lower in the Okhotsk group, indicating that maxillary size does not necessarily constrain the nasal breadth. In addition, despite the presence of obvious geographic clines in anterior nasal shape, posterior choanal shape lacked the north-south geographic cline. This suggests a certain level of morphofunctional independence between the anterior and posterior nasal openings. The observed geographic variations must, however, be partly considered as a reflection of different ancestral traits and population histories of the three groups. Nevertheless, the results indicate that intergroup variations in nasal cavity morphology can be largely explained by climatic conditions. Am. J. Hum. Biol. 28:343-351, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Drivers of protogynous sex change differ across spatial scales.

PubMed

Taylor, Brett M

2014-01-22

The influence of social demography on sex change schedules in protogynous reef fishes is well established, yet effects across spatial scales (in particular, the magnitude of natural variation relative to size-selective fishing effects) are poorly understood. Here, I examine variation in timing of sex change for exploited parrotfishes across a range of environmental, anthropogenic and geographical factors. Results were highly dependent on spatial scale. Fishing pressure was the most influential factor determining length at sex change at the within-island scale where a wide range of anthropogenic pressure existed. Sex transition occurred at smaller sizes where fishing pressure was high. Among islands, however, differences were overwhelmingly predicted by reefal-scale structural features, a pattern evident for all species examined. For the most abundant species, Chlorurus spilurus, length at sex change increased at higher overall densities and greater female-to-male sex ratios at all islands except where targeted by fishermen; here the trend was reversed. This implies differing selective pressures on adult individuals can significantly alter sex change dynamics, highlighting the importance of social structure, demography and the selective forces structuring populations. Considerable life-history responses to exploitation were observed, but results suggest potential fishing effects on demography may be obscured by natural variation at biogeographic scales.

Educational Planning for the Gifted. Overcoming Cultural, Geographic and Socioeconomic Barriers

ERIC Educational Resources Information Center

Baldwin, Alexinia Y., Ed.; And Others

The book presents theoretical considerations and practical recommendations concerned with school planning for gifted children who might not be identified nor have an opportunity to develop their mental capacities because of external influences such as cultural diversity, socioeconomic status, or geographic isolation. Six different approaches to…

Modeling the influence of genetic and environmental variation on the expression of plant life cycles across landscapes.

PubMed

Burghardt, Liana T; Metcalf, C Jessica E; Wilczek, Amity M; Schmitt, Johanna; Donohue, Kathleen

2015-02-01

Organisms develop through multiple life stages that differ in environmental tolerances. The seasonal timing, or phenology, of life-stage transitions determines the environmental conditions to which each life stage is exposed and the length of time required to complete a generation. Both environmental and genetic factors contribute to phenological variation, yet predicting their combined effect on life cycles across a geographic range remains a challenge. We linked submodels of the plasticity of individual life stages to create an integrated model that predicts life-cycle phenology in complex environments. We parameterized the model for Arabidopsis thaliana and simulated life cycles in four locations. We compared multiple "genotypes" by varying two parameters associated with natural genetic variation in phenology: seed dormancy and floral repression. The model predicted variation in life cycles across locations that qualitatively matches observed natural phenology. Seed dormancy had larger effects on life-cycle length than floral repression, and results suggest that a genetic cline in dormancy maintains a life-cycle length of 1 year across the geographic range of this species. By integrating across life stages, this approach demonstrates how genetic variation in one transition can influence subsequent transitions and the geographic distribution of life cycles more generally.

Regional variation in thyroid cancer incidence in Belgium is associated with variation in thyroid imaging and thyroid disease management.

PubMed

Van den Bruel, Annick; Francart, Julie; Dubois, Cecile; Adam, Marielle; Vlayen, Joan; De Schutter, Harlinde; Stordeur, Sabine; Decallonne, Brigitte

2013-10-01

Increased thyroid cancer incidence is at least partially attributed to increased detection and shows considerable regional variation. We investigated whether regional variation in cancer incidence was associated with variations in thyroid disease management. We conducted a retrospective population-based cohort study that involved linking data from the Belgian Health Insurance database and the Belgian Cancer Registry to compare thyroid-related procedures between regions with high and low cancer incidence. Primary outcome measures were rates of TSH testing, imaging, fine-needle aspiration cytology (FNAC), and thyroid surgery. Secondary study outcomes were proportions of subjects with thyrotoxicosis and nodular disease treated with surgery, of subjects treated with surgery preceded by FNAC or with synchronous lymph node dissection, and of thyroid cancer diagnosis after surgery. The rate of TSH testing was similar, but the rate of imaging was lower in the low incidence region. The rate of FNAC was similar, whereas the rate of surgery was lower in the low incidence region (34 [95% CI 33; 35 ] vs 80 [95% CI 79; 81 ] per 100,000 person years in the high incidence region; P < .05). In the low incidence region compared to the high incidence region, surgery represented a less chosen therapy for euthyroid nodular disease patients (47% [95% CI 46; 48] vs 69% [95% CI 68; 70]; P < .05), proportionally more surgery was preceded by FNAC, more cancer was diagnosed after total thyroidectomy, and thyroid cancer patients had more preoperative FNAC and synchronous lymph node dissection. Regional variation in thyroid cancer incidence, most marked for low-risk disease, is associated with different usage of thyroid imaging and surgery, supporting variable detection as a key determinant in geographic variation.

Variation in spawning time promotes genetic variability in population responses to environmental change in a marine fish

PubMed Central

Hutchings, Jeffrey A

2015-01-01

Abstract The level of phenotypic plasticity displayed within a population (i.e. the slope of the reaction norm) reflects the short-term response of a population to environmental change, while variation in reaction norm slopes among populations reflects spatial variation in these responses. Thus far, studies of thermal reaction norm variation have focused on geographically driven adaptation among different latitudes, altitudes or habitats. Yet, thermal variability is a function of both space and time. For organisms that reproduce at different times of year, such variation has the potential to promote adaptive variability in thermal responses for critical early life stages. Using common-garden experiments, we examined the spatial scale of genetic variation in thermal plasticity for early life-history traits among five populations of endangered Atlantic cod (Gadus morhua) that spawn at different times of year. Patterns of plasticity for larval growth and survival suggest that population responses to climate change will differ substantially, with increasing water temperatures posing a considerably greater threat to autumn-spawning cod than to those that spawn in winter or spring. Adaptation to seasonal cooling or warming experienced during the larval stage is suggested as a possible cause. Furthermore, populations that experience relatively cold temperatures during early life might be more sensitive to changes in temperature. Substantial divergence in adaptive traits was evident at a smaller spatial scale than has previously been shown for a marine fish with no apparent physical barriers to gene flow (∼200 km). Our findings highlight the need to consider the impact of intraspecific variation in reproductive timing on thermal adaptation when forecasting the effects of climate change on animal populations. PMID:27293712

Variation in spawning time promotes genetic variability in population responses to environmental change in a marine fish.

PubMed

Oomen, Rebekah A; Hutchings, Jeffrey A

2015-01-01

The level of phenotypic plasticity displayed within a population (i.e. the slope of the reaction norm) reflects the short-term response of a population to environmental change, while variation in reaction norm slopes among populations reflects spatial variation in these responses. Thus far, studies of thermal reaction norm variation have focused on geographically driven adaptation among different latitudes, altitudes or habitats. Yet, thermal variability is a function of both space and time. For organisms that reproduce at different times of year, such variation has the potential to promote adaptive variability in thermal responses for critical early life stages. Using common-garden experiments, we examined the spatial scale of genetic variation in thermal plasticity for early life-history traits among five populations of endangered Atlantic cod (Gadus morhua) that spawn at different times of year. Patterns of plasticity for larval growth and survival suggest that population responses to climate change will differ substantially, with increasing water temperatures posing a considerably greater threat to autumn-spawning cod than to those that spawn in winter or spring. Adaptation to seasonal cooling or warming experienced during the larval stage is suggested as a possible cause. Furthermore, populations that experience relatively cold temperatures during early life might be more sensitive to changes in temperature. Substantial divergence in adaptive traits was evident at a smaller spatial scale than has previously been shown for a marine fish with no apparent physical barriers to gene flow (∼200 km). Our findings highlight the need to consider the impact of intraspecific variation in reproductive timing on thermal adaptation when forecasting the effects of climate change on animal populations.

A Multilevel Model for Comorbid Outcomes: Obesity and Diabetes in the US

PubMed Central

Congdon, Peter

2010-01-01

Multilevel models are overwhelmingly applied to single health outcomes, but when two or more health conditions are closely related, it is important that contextual variation in their joint prevalence (e.g., variations over different geographic settings) is considered. A multinomial multilevel logit regression approach for analysing joint prevalence is proposed here that includes subject level risk factors (e.g., age, race, education) while also taking account of geographic context. Data from a US population health survey (the 2007 Behavioral Risk Factor Surveillance System or BRFSS) are used to illustrate the method, with a six category multinomial outcome defined by diabetic status and weight category (obese, overweight, normal). The influence of geographic context is partly represented by known geographic variables (e.g., county poverty), and partly by a model for latent area influences. In particular, a shared latent variable (common factor) approach is proposed to measure the impact of unobserved area influences on joint weight and diabetes status, with the latent variable being spatially structured to reflect geographic clustering in risk. PMID:20616977

Wing geometry of Phlebotomus stantoni and Sergentomyia hodgsoni from different geographical locations in Thailand.

PubMed

Sumruayphol, Suchada; Chittsamart, Boonruam; Polseela, Raxsina; Sriwichai, Patchara; Samung, Yudthana; Apiwathnasorn, Chamnarn; Dujardin, Jean-Pierre

2017-01-01

Geographic populations of the two main sandflies genera present in Thailand were studied for species and population identification. Size and shape of Phlebotomus stantoni and Sergentomyia hodgsoni from different island and mainland locations were examined by landmark-based geometric morphometrics. Intraspecific and interspecific wing comparison was carried out based on 12 anatomical landmarks. The wing centroid size of P. stantoni was generally larger than that of S. hodgsoni. Within both species, wings from the continent were significantly larger than those from island populations. Size variation could be significant between geographic locations, but could also overlap between genera. The wing venation geometry showed non-overlapping differences between two species. The within-species variation of geometric shape between different geographical locations was highly significant, but it could not interfere with the interspecies difference. The lack of species overlapping in shape, and the high discrimination between geographic populations, make geometric shape a promising character for future taxonomic and epidemiological studies. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Cultural variation in savannah sparrow, Passerculus sandwichensis, songs: an analysis using the meme concept.

PubMed

Burnell

1998-10-01

I used the meme concept to investigate patterns of cultural variation among the songs of eight, geographically distinct populations of savannah sparrows. Memes composed of only one syllable were geographically widespread and randomly distributed among populations, but memes of two-, three- and four-syllables became progressively more restricted in their geographical distribution. Thus, the populations were memetically more similar with respect to one-syllable memes and more divergent with respect to larger memes. These results suggest that differences in memetic mutation rates and susceptibility to loss by memetic drift could be sufficient to create the observed pattern of greater divergence among populations for large memes. Copyright 1998 The Association for the Study of Animal Behaviour.

Genetic variation, climate models and the ecological genetics of Larix occidentalis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rehfeldt, G.E.

1995-12-31

Provenance tests of 138 populations of Larix occidentalis revealed genetic differentiation for eight variables describing growth, phenology, tolerance to spring frosts, effects of Meria laricis needle cast, and survival. Geographic variables accounted for as much as 34% of the variance among Rocky Mountain populations. Patterns of genetic variation were dominated by the effects of latitude and elevation, with populations from the north and from high elevations having the lowest growth potential, the least tolerance to the needle cast, and the lowest survival. However, the slope of the geographic clines was relatively flat. Populations in the same geographic area, for instance,more » need to be separated by about 500 m in elevation before genetic differentiation can be expected.« less

Environmental predictors of dispersal traits across a species' geographic range.

PubMed

LaRue, Elizabeth A; Holland, Jeffrey D; Emery, Nancy C

2018-05-30

Variation in habitat quality and quantity drive selection on dispersal traits in heterogeneous environments, but the extent to which environmental conditions predict geographic variation in dispersal is rarely evaluated. We assessed dispersal trait variation across the range of Cakile edentula var. lacustris, an annual herb that occupies beaches of the Great Lakes. Cakile edentula has dimorphic fruits that each contain one dispersive and one non-dispersive seed. Previous work showed that plant height, branching density, and dispersive fruit wing-loading can determine the distance that seeds disperse locally by wind, while pericarp thickness influences the distance they disperse by water. We tested if these traits vary predictably with latitude across the species' geographic range, and if variation in dispersal characteristics can be predicted by the quality and quantity of habitat available at a site. We observed that the dispersive fruits from northern and southern populations had thinner pericarps than those from the interior of the species' range, reflecting reduced long-distance dispersal by water at both range limits. Plants at the northern range limit were shorter with less dense branching and lower wing-loading than populations elsewhere in the range, suggesting that these populations have enhanced local wind dispersal. In contrast, southern populations exhibited traits with inconsistent effects on wind dispersal: plants tended to be short, which facilitates wind dispersal in C. edentula, but also had relatively higher branching density and distal segment wing-loading that reduce wind dispersal. Geographic variation in maternal plant height and branching density was partially explained by variation in habitat quality, which declined at the species' range limits. In addition, population differences in branching density, fruit wing-loading, and pericarp thickness were predicted by the abundance and distribution of beach habitat. Finally, a common garden analysis recovered latitudinal patterns for the dispersal traits associated with fruits, but not those associated with maternal architecture. Thus, the geographic patterns of dispersal trait variation that we observed likely reflect responses to past selection by the distribution, abundance, and quality of habitat, strong plasticity in dispersal traits, and the effects dispersal itself has in shaping local adaptation by driving gene flow among populations. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Upper atmosphere differences between northern and southern high latitudes: The role of magnetic field asymmetry

NASA Astrophysics Data System (ADS)

Förster, Matthias; Cnossen, Ingrid

2013-09-01

The nondipolar portions of the Earth's main magnetic field constitute substantial differences between the two hemispheres. Beside the magnetic flux densities and patterns being different in the Northern Hemisphere (NH) and Southern Hemisphere (SH), also the offset between the invariant magnetic and the geographic poles is larger in the SH than in the NH. We investigated the effects of this magnetic field asymmetry on the high-latitude thermosphere and ionosphere using global numerical simulations and compared our results with recent observations. While the effects on the high-latitude plasma convection are small, the consequences for the neutral wind circulation are substantial. The cross-polar neutral wind and ion drift velocities are generally larger in the NH than the SH, and the hemispheric difference shows a semidiurnal variation. The neutral wind vorticity is likewise larger in the NH than in the SH, with the difference probably becoming larger for higher solar activity. In contrast, the spatial variance of the neutral wind is considerably larger in the SH polar region, with the hemispheric difference showing a strong semidiurnal variation. Its phase is similar to the phase of the semidiurnal variation of the hemispheric magnitude differences. Hemispheric differences in ion drift and neutral wind magnitude are most likely caused partly by the larger magnetic flux densities in the near-polar regions of the SH and partly by the larger offset between the invariant and geographic pole in the SH, while differences in spatial variance are probably just caused by the latter. We conclude that the asymmetry of the magnetic field, both in strength and in orientation, establishes substantial hemispheric differences in the neutral wind and plasma drift in the high-latitude upper atmosphere, which can help to explain observed hemispheric differences found with the Cluster/Electron Drift Instrument (EDI) and the Challenging Minisatellite Payload (CHAMP).

Comparative biology of the crab Goniopsis cruentata: geographic variation of body size, sexual maturity, and allometric growth

NASA Astrophysics Data System (ADS)

de Lira, José Jonathas Pereira Rodrigues; Calado, Tereza Cristina dos Santos; Rezende, Carla Ferreira; Silva, José Roberto Feitosa

2015-12-01

Geographic variation of phenotypic traits is common across species and is often associated with variation in environmental conditions. Here, we found larger bodies and larger size at maturity in a northward, lower latitude population of the crab Goniopsis cruentata, which inhabits a hotter, drier environment in comparison with a southward, higher latitude population. Furthermore, the juvenile male gonopods grow more relative to body size in the population characterized by maturation at a smaller size. In contrast, the female abdomen widens at a higher rate among the late maturing population. These results provide further evidence that local environmental conditions play a role in phenotypic variation between populations inhabiting different latitudes. Moreover, they also show that variation in size at maturity and body size can lead to divergent allometric patterns of sexual characteristics that can have a sex-specific response.

Geographic variation and sociodemographic disparity in the use of oxaliplatin-containing chemotherapy in patients with stage III colon cancer.

PubMed

Panchal, Janki M; Lairson, David R; Chan, Wenyaw; Du, Xianglin L

2013-06-01

This study examined the geographic variation and sociodemographic disparities in the use of oxaliplatin chemotherapy, which has not been widely studied in the past. Our results suggest that chemotherapy use varies across geographic regions. Patterns of use that relate specifically to oxaliplatin-containing chemotherapy can inform providers and researchers how newer regimens are being used as standard chemotherapy in a real-world setting. According to the National Cancer Comprehensive Network (NCCN), oxaliplatin with 5-fluorouracil and leucovorin (5-FU/LV) is the recommended adjuvant chemotherapy for patients with resected stage III colon cancer. Age and race are considered strong predictors of chemotherapy receipt, whereas geographic disparity has received minimal attention. The purpose of this study was to examine geographic variation and sociodemographic disparity in the use of chemotherapy in patients with stage III colon cancer, focusing specifically on oxaliplatin. A retrospective cohort of 4106 Medicare patients was identified from the Surveillance, Epidemiology and End Results (SEER)/Medicare linked database. Descriptive statistics show how oxaliplatin-containing chemotherapy was used in various geographic regions among different age and racial groups. Multiple logistic regression analysis was performed to examine the relationship between receipt of oxaliplatin-containing chemotherapy and geographic region while adjusting for other sociodemographic and tumor characteristics. Only 49% of the patients with stage III disease received adjuvant chemotherapy within 3 to 6 months of colon cancer-specific surgery. Patients aged 66 to 70 years were 78% more likely to receive chemotherapy than were those aged 80 years and older (P<.001). Patients in less urban regions were approximately 42% less likely to receive oxaliplatin chemotherapy than those residing in a big metro region (odds ratio [OR], 0.58; P=.008). Chemotherapy use varies across geographic regions, especially for new chemotherapy drugs like oxaliplatin. Further research is needed to identify the causes of this geographic disparity and ways to provide high-quality cancer care to all patients according to their preferences and needs. Copyright © 2013 Elsevier Inc. All rights reserved.

Size and shape in Melipona quadrifasciata anthidioides Lepeletier, 1836 (Hymenoptera; Meliponini).

PubMed

Nunes, L A; Passos, G B; Carvalho, C A L; Araújo, E D

2013-11-01

This study aimed to identify differences in wing shape among populations of Melipona quadrifasciata anthidioides obtained in 23 locations in the semi-arid region of Bahia state (Brazil). Analysis of the Procrustes distances among mean wing shapes indicated that population structure did not determine shape variation. Instead, populations were structured geographically according to wing size. The Partial Mantel Test between morphometric (shape and size) distance matrices and altitude, taking geographic distances into account, was used for a more detailed understanding of size and shape determinants. A partial Mantel test between morphometris (shape and size) variation and altitude, taking geographic distances into account, revealed that size (but not shape) is largely influenced by altitude (r = 0.54 p < 0.01). These results indicate greater evolutionary constraints for the shape variation, which must be directly associated with aerodynamic issues in this structure. The size, however, indicates that the bees tend to have larger wings in populations located at higher altitudes.

Flock-level prevalence, geographical distribution, and seasonal variation of avian reovirus among broiler flocks in Ontario.

PubMed

Nham, Eric G; Pearl, David L; Slavic, Durda; Ouckama, Rachel; Ojkic, Davor; Guerin, Michele T

2017-08-01

Avian reovirus (ARV) is an economically significant pathogen of broiler chickens. Our objective was to determine the prevalence, geographical distribution, and seasonal variation of ARV infection among commercial broiler flocks in Ontario, Canada during grow-out. A cross-sectional study of 231 randomly selected flocks was conducted from July 2010 to January 2012. Fifteen blood samples, 15 whole intestines, and 15 cloacal swabs per flock were collected at slaughter; ELISA and PCR were used to determine a flock's ARV exposure status. Avian reovirus prevalence was 91% (95% CI: 87 to 94). District alone did not significantly explain the overall variation in the prevalence of ARV (univariable logistic regression; P = 0.073), although geographical differences were identified. The odds of ARV presence were significantly lower in the summer/autumn compared to the winter/spring (univariable exact logistic regression; P < 0.001). There was no association between flock mortality and flock ELISA mean titer or PCR status.

Flock-level prevalence, geographical distribution, and seasonal variation of avian reovirus among broiler flocks in Ontario

PubMed Central

Nham, Eric G.; Pearl, David L.; Slavic, Durda; Ouckama, Rachel; Ojkic, Davor; Guerin, Michele T.

2017-01-01

Avian reovirus (ARV) is an economically significant pathogen of broiler chickens. Our objective was to determine the prevalence, geographical distribution, and seasonal variation of ARV infection among commercial broiler flocks in Ontario, Canada during grow-out. A cross-sectional study of 231 randomly selected flocks was conducted from July 2010 to January 2012. Fifteen blood samples, 15 whole intestines, and 15 cloacal swabs per flock were collected at slaughter; ELISA and PCR were used to determine a flock’s ARV exposure status. Avian reovirus prevalence was 91% (95% CI: 87 to 94). District alone did not significantly explain the overall variation in the prevalence of ARV (univariable logistic regression; P = 0.073), although geographical differences were identified. The odds of ARV presence were significantly lower in the summer/autumn compared to the winter/spring (univariable exact logistic regression; P < 0.001). There was no association between flock mortality and flock ELISA mean titer or PCR status. PMID:28761188

Mapping the determinants of health inequalities in social space: can Bourdieu help us?

PubMed

Gatrell, Anthony C; Popay, Jennie; Thomas, Carol

2004-09-01

Considerable research effort has been devoted to describing and explaining, at a variety of spatial scales, geographical inequalities in health outcomes within the developed world. Following Bourdieu, we argue that structures of the social world may be revealed in different kinds of 'social' space. We outline the relational thinking that underlies these ideas. We then 'map', using correspondence analysis (on which Bourdieu himself drew), the structure of social space according to the differential availability of some forms of capital, across four study areas in north-west England. We use logistic regression analysis to explain variation in psychological morbidity (GHQ-score) and then portray the significant predictors of morbidity using multiple correspondence analysis. The area of residence of the survey respondents is used to associate them with particular locations in these social spaces.

Activity response to climate seasonality in species with fossorial habits: a niche modeling approach using the lowland burrowing treefrog (Smilisca fodiens).

PubMed

Encarnación-Luévano, Alondra; Rojas-Soto, Octavio R; Sigala-Rodríguez, J Jesús

2013-01-01

The importance of climatic conditions in shaping the geographic distribution of amphibian species is mainly associated to their high sensitivity to environmental conditions. How they cope with climate gradients through behavioral adaptations throughout their distribution is an important issue due to the ecological and evolutionary implications for population viability. Given their low dispersal abilities, the response to seasonal climate changes may not be migration, but behavioral and physiological adaptations. Here we tested whether shifts in climatic seasonality can predict the temporal variation of surface activity of the fossorial Lowland Burrowing Treefrog (Smilisca fodiens) across its geographical distribution. We employed Ecological Niche Modeling (ENM) to perform a monthly analysis of spatial variation of suitable climatic conditions (defined by the July conditions, the month of greatest activity), and then evaluated the geographical correspondence of monthly projections with the occurrence data per month. We found that the species activity, based on the species' occurrence data, corresponds with the latitudinal variation of suitable climatic conditions. Due to the behavioral response of this fossorial frog to seasonal climate variation, we suggest that precipitation and temperature have played a major role in the definition of geographical and temporal distribution patterns, as well as in shaping behavioral adaptations to local climatic conditions. This highlights the influence of macroclimate on shaping activity patterns and the important role of fossorials habits to meet the environmental requirements necessary for survival.

Temporal trends and geographic variation of lower-extremity amputation in patients with peripheral artery disease: results from U.S. Medicare 2000-2008.

PubMed

Jones, W Schuyler; Patel, Manesh R; Dai, David; Subherwal, Sumeet; Stafford, Judith; Calhoun, Sarah; Peterson, Eric D

2012-11-20

This study sought to characterize temporal trends, patient-specific factors, and geographic variation associated with amputation in patients with lower-extremity peripheral artery disease (LE PAD) during the study period. Amputation represents the end-stage failure for those with LE PAD, and little is known about the rates and geographic variation in the use of LE amputation. By using data from the Centers for Medicare & Medicaid Services (CMS) from January 1, 2000, to December 31, 2008, we examined national patterns of LE amputation among patients age 65 years or more with PAD. Multivariable logistic regression was used to adjust regional results for other patient demographic and clinical factors. Among 2,730,742 older patients with identified PAD, the overall rate of LE amputation decreased from 7,258 per 100,000 patients with PAD to 5,790 per 100,000 (p < 0.001 for trend). Male sex, black race, diabetes mellitus, and renal disease were all independent predictors of LE amputation. The adjusted odds ratio of LE amputation per year between 2000 and 2008 was 0.95 (95% CI: 0.95-0.95, p < 0.001). From 2000 to 2008, LE amputation rates decreased significantly among patients with PAD. However, there remains significant patient and geographic variation in amputation rates across the United States. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Regional contamination versus regional dietary differences: Understanding geographic variation in brominated and chlorinated contaminant levels in polar bears

USGS Publications Warehouse

McKinney, M.A.; Letcher, R.J.; Aars, Jon; Born, E.W.; Branigan, M.; Dietz, R.; Evans, T.J.; Gabrielsen, G.W.; Muir, D.C.G.; Peacock, E.; Sonne, C.

2011-01-01

The relative contribution of regional contamination versus dietary differences to geographic variation in polar bear (Ursus maritimus) contaminant levels is unknown. Dietary variation between Alaska Canada, East Greenland, and Svalbard subpopulations was assessed by muscle nitrogen and carbon stable isotope (?? 15N, ?? 13C) and adipose fatty acid (FA) signatures relative to their main prey (ringed seals). Western and southern Hudson Bay signatures were characterized by depleted ?? 15N and ??13C, lower proportions of C20 and C22 monounsaturated FAs and higher proportions of C18 and longer chain polyunsaturated FAs. East Greenland and Svalbard signatures were reversed relative to Hudson Bay. Alaskan ?? 2011 American Chemical Society.

Morphological variation in Sarracenia purpurea (Sarraceniaceae): geographic, environmental, and taxonomic correlates.

PubMed

Ellison, Aaron M; Buckley, Hannah L; Miller, Thomas E; Gotelli, Nicholas J

2004-11-01

Geographic variation in morphology reflects phenotypic responses to environmental gradients and evolutionary history of populations and species and may indicate local or regional changes in environmental conditions. The pitcher plant (Sarracenia purpurea) illustrates these principles. At local scales, its morphology reflects nutrient availability. At points along its broad geographic range (from Florida to northern Canada) morphology has been used to distinguish subspecies and varieties, but there has been no detailed study of the continuum of morphological variation across this entire range. Patterns of morphological variation in S. purpurea were characterized as a function of climatic and environmental conditions at 39 sites spanning its range. Differences in pitcher size and shape were strongly correlated with temperature, annual precipitation, and availability of ammonium and calcium in peat pore water. Pitcher shape (lip width, mouth diameter, and pitcher width) in Florida panhandle populations differed significantly from pitcher shape of all other populations, even after accounting for environmental correlations. In contrast, the northern and southern subspecies of S. purpurea (the latter exclusive of the Florida panhandle populations) cannot be distinguished based on these morphological measurements alone. These results support a recent proposal that identifies the Florida populations as a distinct species, Sarracenia rosea.

Climate and local abundance in freshwater fishes

PubMed Central

Knouft, Jason H.; Anthony, Melissa M.

2016-01-01

Identifying factors regulating variation in numbers of individuals among populations across a species' distribution is a fundamental goal in ecology. A common prediction, often referred to as the abundant-centre hypothesis, suggests that abundance is highest near the centre of a species' range. However, because of the primary focus on the geographical position of a population, this framework provides little insight into the environmental factors regulating local abundance. While range-wide variation in population abundance associated with environmental conditions has been investigated in terrestrial species, the relationship between climate and local abundance in freshwater taxa across species' distributions is not well understood. We used GIS-based temperature and precipitation data to determine the relationships between climatic conditions and range-wide variation in local abundance for 19 species of North American freshwater fishes. Climate predicted a portion of the variation in local abundance among populations for 18 species. In addition, the relationship between climatic conditions and local abundance varied among species, which is expected as lineages partition the environment across geographical space. The influence of local habitat quality on species persistence is well documented; however, our results also indicate the importance of climate in regulating population sizes across a species geographical range, even in aquatic taxa. PMID:27429769

Geographic variations in female breast cancer incidence in relation to ambient air emissions of polycyclic aromatic hydrocarbons.

PubMed

Large, Courtney; Wei, Yudan

2017-07-01

A significant geographic variation of breast cancer incidence exists, with incidence rates being much higher in industrialized regions. The objective of the current study was to assess the role of environmental factors such as exposure to ambient air pollution, specifically carcinogenic polycyclic aromatic hydrocarbons (PAHs) that may be playing in the geographic variations in breast cancer incidence. Female breast cancer incidence and ambient air emissions of PAHs were examined in the northeastern and southeastern regions of the USA by analyzing data from the Surveillance, Epidemiology, and End Results (SEER) Program and the State Cancer Profiles of the National Cancer Institute and from the Environmental Protection Agency. Linear regression analysis was conducted to evaluate the association between PAH emissions and breast cancer incidence in unadjusted and adjusted models. Significantly higher age-adjusted incidence rates of female breast cancer were seen in northeastern SEER regions, when compared to southeastern regions, during the years of 2000-2012. After adjusting for potential confounders, emission densities of total PAHs and four carcinogenic individual PAHs (benzo[a]pyrene, dibenz[a,h]anthracene, naphthalene, and benzo[b]fluoranthene) showed a significantly positive association with annual incidence rates of breast cancer, with a β of 0.85 (p = 0.004), 58.37 (p = 0.010), 628.56 (p = 0.002), 0.44 (p = 0.041), and 77.68 (p = 0.002), respectively, among the northeastern and southeastern states. This study suggests a potential relationship between ambient air emissions of carcinogenic PAHs and geographic variations of female breast cancer incidence in the northeastern and southeastern US. Further investigations are needed to explore these interactions and elucidate the role of PAHs in regional variations of breast cancer incidence.

Trends and geographic patterns in drug-poisoning death rates in the U.S., 1999-2009.

PubMed

Rossen, Lauren M; Khan, Diba; Warner, Margaret

2013-12-01

Drug poisoning mortality has increased substantially in the U.S. over the past 3 decades. Previous studies have described state-level variation and urban-rural differences in drug-poisoning deaths, but variation at the county level has largely not been explored in part because crude county-level death rates are often highly unstable. The goal of the study was to use small-area estimation techniques to produce stable county-level estimates of age-adjusted death rates (AADR) associated with drug poisoning for the U.S., 1999-2009, in order to examine geographic and temporal variation. Population-based observational study using data on 304,087 drug-poisoning deaths in the U.S. from the 1999-2009 National Vital Statistics Multiple Cause of Death Files (analyzed in 2012). Because of the zero-inflated and right-skewed distribution of drug-poisoning death rates, a two-stage modeling procedure was used in which the first stage modeled the probability of observing a death for a given county and year, and the second stage modeled the log-transformed drug-poisoning death rate given that a death occurred. Empirical Bayes estimates of county-level drug-poisoning death rates were mapped to explore temporal and geographic variation. Only 3% of counties had drug-poisoning AADRs greater than ten per 100,000 per year in 1999-2000, compared to 54% in 2008-2009. Drug-poisoning AADRs grew by 394% in rural areas compared to 279% for large central metropolitan counties, but the highest drug-poisoning AADRs were observed in central metropolitan areas from 1999 to 2009. There was substantial geographic variation in drug-poisoning mortality across the U.S. Published by American Journal of Preventive Medicine on behalf of American Journal of Preventive Medicine.

Geographic variation in the advertisement calls of Hyla eximia and its possible explanations

PubMed Central

Rodríguez-Tejeda, Ruth E.; Méndez-Cárdenas, María Guadalupe; Islas-Villanueva, Valentina

2014-01-01

Populations of species occupying large geographic ranges are often phenotypically diverse as a consequence of variation in selective pressures and drift. This applies to attributes involved in mate choice, particularly when both geographic range and breeding biology overlap between related species. This condition may lead to interference of mating signals, which would in turn promote reproductive character displacement (RCD). We investigated whether variation in the advertisement call of the mountain treefrog (Hyla eximia) is linked to geographic distribution with respect to major Mexican river basins (Panuco, Lerma, Balsas and Magdalena), or to coexistence with its sister (the canyon treefrog, Hyla arenicolor) or another related species (the dwarf treefrog, Tlalocohyla smithii). We also evaluated whether call divergence across the main river basins could be linked to genetic structure. We found that the multidimensional acoustic space of calls from two basins where H. eximia currently interacts with T. smithii, was different from the acoustic space of calls from H. eximia elsewhere. Individuals from these two basins were also distinguishable from the rest by both the phylogeny inferred from mitochondrial sequences, and the genetic structure inferred from nuclear markers. The discordant divergence of H. eximia advertisement calls in the two separate basins where its geographic range overlaps that of T. smithii can be interpreted as the result of two independent events of RCD, presumably as a consequence of acoustic interference in the breeding choruses, although more data are required to evaluate this possibility. PMID:25024904

Geographic variation in the advertisement calls of Hyla eximia and its possible explanations.

PubMed

Rodríguez-Tejeda, Ruth E; Méndez-Cárdenas, María Guadalupe; Islas-Villanueva, Valentina; Macías Garcia, Constantino

2014-01-01

Populations of species occupying large geographic ranges are often phenotypically diverse as a consequence of variation in selective pressures and drift. This applies to attributes involved in mate choice, particularly when both geographic range and breeding biology overlap between related species. This condition may lead to interference of mating signals, which would in turn promote reproductive character displacement (RCD). We investigated whether variation in the advertisement call of the mountain treefrog (Hyla eximia) is linked to geographic distribution with respect to major Mexican river basins (Panuco, Lerma, Balsas and Magdalena), or to coexistence with its sister (the canyon treefrog, Hyla arenicolor) or another related species (the dwarf treefrog, Tlalocohyla smithii). We also evaluated whether call divergence across the main river basins could be linked to genetic structure. We found that the multidimensional acoustic space of calls from two basins where H. eximia currently interacts with T. smithii, was different from the acoustic space of calls from H. eximia elsewhere. Individuals from these two basins were also distinguishable from the rest by both the phylogeny inferred from mitochondrial sequences, and the genetic structure inferred from nuclear markers. The discordant divergence of H. eximia advertisement calls in the two separate basins where its geographic range overlaps that of T. smithii can be interpreted as the result of two independent events of RCD, presumably as a consequence of acoustic interference in the breeding choruses, although more data are required to evaluate this possibility.

Spatial analysis of harmonic oscillation of gypsy moth outbreak intensity

Treesearch

Kyle J. Haynes; Andrew M. Liebhold; Derek M. Johnson

2009-01-01

Outbreaks of many forest-defoliating insects are synchronous over broad geographic areas and occur with a period of approximately 10 years. Within the range of the gypsy moth in North America, however, there is considerable geographic heterogeneity in strength of periodicity and the frequency of outbreaks. Furthermore, gypsy moth outbreaks exhibit two significant...

Spatial distribution and influence factors of interprovincial terrestrial physical geographical names in China

NASA Astrophysics Data System (ADS)

Zhang, S.; Wang, Y.; Ju, H.

2017-12-01

The interprovincial terrestrial physical geographical entities are the key areas of regional integrated management. Based on toponomy dictionaries and different thematic maps, the attributes and the spatial extent of the interprovincial terrestrial physical geographical names (ITPGN, including terrain ITPGN and water ITPGN) were extracted. The coefficient of variation and Moran's I were combined together to measure the spatial variation and spatial association of ITPGN. The influencing factors of the distribution of ITPGN and the implications for the regional management were further discussed. The results showed that 11325 ITPGN were extracted, including 7082 terrain ITPGN and 4243 water ITPGN. Hunan Province had the largest number of ITPGN in China, and Shanghai had the smallest number. The spatial variance of the terrain ITPGN was larger than that of the water ITPGN, and the ITPGN showed a significant agglomeration phenomenon in the southern part of China. Further analysis showed that the number of ITPGN was positively related with the relative elevation and the population where the relative elevation was lower than 2000m and the population was less than 50 million. But the number of ITPGN showed a negative relationship with the two factors when their values became larger, indicating a large number of unnamed entities existed in complex terrain areas and a decreasing number of terrestrial physical geographical entities in densely populated area. Based on these analysis, we suggest the government take the ITPGN as management units to realize a balance development between different parts of the entities and strengthen the geographical names census and the nomination of unnamed interprovincial physical geographical entities. This study also demonstrated that the methods of literature survey, coefficient of variation and Moran's I can be combined to enhance the understanding of the spatial pattern of ITPGN.

Population-Based Analysis and Projections of Liver Supply Under Redistricting.

PubMed

Parikh, Neehar D; Marrero, Wesley J; Sonnenday, Christopher J; Lok, Anna S; Hutton, David W; Lavieri, Mariel S

2017-09-01

To reduce the geographic heterogeneity in liver transplant allocation, the United Network of Organ Sharing has proposed redistricting, which is impacted by both donor supply and liver transplantation demand. We aimed to determine the impact of demographic changes on the redistricting proposal and characterize causes behind geographic heterogeneity in donor supply. We analyzed adult donors from 2002 to 2014 from the United Network of Organ Sharing database and calculated regional liver donation and utilization stratified by age, race, and body mass index. We used US population data to make regional projections of available donors from 2016 to 2025, incorporating the proposed 8-region redistricting plan. We used donors/100 000 population age 18 to 84 years (D/100K) as a measure of equity. We calculated a coefficient of variation (standard deviation/mean) for each regional model. We performed an exploratory analysis where we used national rates of donation, utilization and both for each regional model. The overall projected D/100K will decrease from 2.53 to 2.49 from 2016 to 2025. The coefficient of variation in 2016 is expected to be 20.3% in the 11-region model and 13.2% in the 8-region model. We found that standardizing regional donation and utilization rates would reduce geographic heterogeneity to 4.9% in the 8-region model and 4.6% in the 11-region model. The 8-region allocation model will reduce geographic variation in donor supply to a significant extent; however, we project that geographic disparity will marginally increase over time. Though challenging, interventions to better standardize donation and utilization rates would be impactful in reducing geographic heterogeneity in organ supply.

Effects of English admixture and geographic distance on anthropometric variation and genetic structure in 19th-century Ireland.

PubMed

Relethford, J H

1988-05-01

The analysis of anthropometric data often allows investigation of patterns of genetic structure in historical populations. This paper focuses on interpopulational anthropometric variation in seven populations in Ireland using data collected in the 1890s. The seven populations were located within a 120-km range along the west coast of Ireland and include islands and mainland isolates. Two of the populations (the Aran Islands and Inishbofin) have a known history of English admixture in earlier centuries. Ten anthropometric measures (head length, breadth, and height; nose length and breadth; bizygomatic and bigonial breadth; stature; hand length; and forearm length) on 259 adult Irish males were analyzed following age adjustment. Discriminant and canonical variates analysis were used to determine the degree and pattern of among-group variation. Mahalanobis' distance measure, D2, was computed between each pair of populations and compared to distance measures based on geographic distance and English admixture (a binary measure indicating whether either of a pair of populations had historical indications of admixture). In addition, surname frequencies were used to construct distance measures based on random isonymy. Correlations were computed between distance measures, and their probabilities were derived using the Mantel matrix permutation method. English admixture has the greatest effect on anthropometric variation among these populations, followed by geographic distance. The correlation between anthropometric distance and geographic distance is not significant (r = -0.081, P = .590), but the correlation of admixture and anthropometric distance is significant (r = 0.829, P = .047). When the two admixed populations are removed from the analysis the correlation between geographic and anthropometric distance becomes significant (r = 0.718, P = .025). Isonymy distance shows a significant correlation with geographic distance (r = 0.425, P = .046) but not with admixture distance (r = -0.052, P = .524). The fact that anthropometrics show past patterns of gene flow and surnames do not reflects the greater impact of stochastic processes on surnames, along with the continued extinction of surnames. This study shows that 1) anthropometrics can be extremely useful in assessing population structure and history, 2) differential gene flow into populations can have a major impact on local genetic structure, and 3) microevolutionary processes can have different effects on biological characters and surnames.

Drift-driven evolution of electric signals in a Neotropical knifefish.

PubMed

Picq, Sophie; Alda, Fernando; Bermingham, Eldredge; Krahe, Rüdiger

2016-09-01

Communication signals are highly diverse traits. This diversity is usually assumed to be shaped by selective forces, whereas the null hypothesis of divergence through drift is often not considered. In Panama, the weakly electric fish Brachyhypopomus occidentalis is widely distributed in multiple independent drainage systems, which provide a natural evolutionary laboratory for the study of genetic and signal divergence in separate populations. We quantified geographic variation in the electric signals of 109 fish from five populations, and compared it to the neutral genetic variation estimated from cytochrome oxidase I (COI) sequences of the same individuals, to test whether drift may be driving divergence of their signals. Signal distances were highly correlated with genetic distances, even after controlling for geographic distances, suggesting that drift alone is sufficient to explain geographic variation in electric signals. Significant differences at smaller geographic scales (within drainages) showed, however, that electric signals may evolve at a faster rate than expected under drift, raising the possibility that additional adaptive forces may be contributing to their evolution. Overall, our data point to stochastic forces as main drivers of signal evolution in this species and extend the role of drift in the evolution of communication systems to fish and electrocommunication. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Intraspecific N and P stoichiometry of Phragmites australis: geographic patterns and variation among climatic regions.

PubMed

Hu, Yu-Kun; Zhang, Ya-Lin; Liu, Guo-Fang; Pan, Xu; Yang, Xuejun; Li, Wen-Bing; Dai, Wen-Hong; Tang, Shuang-Li; Xiao, Tao; Chen, Ling-Yun; Xiong, Wei; Song, Yao-Bin; Dong, Ming

2017-02-24

Geographic patterns in leaf stoichiometry reflect plant adaptations to environments. Leaf stoichiometry variations along environmental gradients have been extensively studied among terrestrial plants, but little has been known about intraspecific leaf stoichiometry, especially for wetland plants. Here we analyzed the dataset of leaf N and P of a cosmopolitan wetland species, Phragmites australis, and environmental (geographic, climate and soil) variables from literature and field investigation in natural wetlands distributed in three climatic regions (subtropical, temperate and highland) across China. We found no clear geographic patterns in leaf nutrients of P. australis across China, except for leaf N:P ratio increasing with altitude. Leaf N and N:P decreased with mean annual temperature (MAT), and leaf N and P were closely related to soil pH, C:N ratio and available P. Redundancy analysis showed that climate and soil variables explained 62.1% of total variation in leaf N, P and N:P. Furthermore, leaf N in temperate region and leaf P in subtropical region increased with soil available P, while leaf N:P in subtropical region decreased with soil pH. These patterns in P. australis different from terrestrial plants might imply that changes in climate and soil properties can exert divergent effects on wetland and terrestrial ecosystems.

Geographical and Temporal Variations in Female Breast Cancer Mortality in the Municipalities of Andalusia (Southern Spain).

PubMed

Ocaña-Riola, Ricardo; Montaño-Remacha, Carmen; Mayoral-Cortés, José María

2016-11-22

The last published figures have shown geographical variations in mortality with respect to female breast cancer in European countries. However, national health policies need a dynamic image of the geographical variations within the country. The aim of this paper was to describe the spatial distribution of age-specific mortality rates from female breast cancer in the municipalities of Andalusia (southern Spain) and to analyze its evolution over time from 1981 to 2012. An ecological study was devised. Two spatio-temporal hierarchical Bayesian models were estimated. One of these was used to estimate the age-specific mortality rate for each municipality, together with its time trends, and the other was used to estimate the age-specific rate ratio compared with Spain as a whole. The results showed that 98% of the municipalities exhibited a decreasing or a flat mortality trend for all the age groups. In 2012, the geographical variability of the age-specific mortality rates was small, especially for population groups below 65. In addition, more than 96.6% of the municipalities showed an age-specific mortality rate similar to the corresponding rate for Spain, and there were no identified significant clusters. This information will contribute towards a reflection on the past, present and future of breast cancer outcomes in Andalusia.

Geographical and Temporal Variations in Female Breast Cancer Mortality in the Municipalities of Andalusia (Southern Spain)

PubMed Central

Ocaña-Riola, Ricardo; Montaño-Remacha, Carmen; Mayoral-Cortés, José María

2016-01-01

The last published figures have shown geographical variations in mortality with respect to female breast cancer in European countries. However, national health policies need a dynamic image of the geographical variations within the country. The aim of this paper was to describe the spatial distribution of age-specific mortality rates from female breast cancer in the municipalities of Andalusia (southern Spain) and to analyze its evolution over time from 1981 to 2012. An ecological study was devised. Two spatio-temporal hierarchical Bayesian models were estimated. One of these was used to estimate the age-specific mortality rate for each municipality, together with its time trends, and the other was used to estimate the age-specific rate ratio compared with Spain as a whole. The results showed that 98% of the municipalities exhibited a decreasing or a flat mortality trend for all the age groups. In 2012, the geographical variability of the age-specific mortality rates was small, especially for population groups below 65. In addition, more than 96.6% of the municipalities showed an age-specific mortality rate similar to the corresponding rate for Spain, and there were no identified significant clusters. This information will contribute towards a reflection on the past, present and future of breast cancer outcomes in Andalusia. PMID:27879690

Geographic variation in body size and its relationship with environmental gradients in the Oriental Garden Lizard, Calotes versicolor.

PubMed

Wei, Xiaomei; Yan, Linmiao; Zhao, Chengjian; Zhang, Yueyun; Xu, Yongli; Cai, Bo; Jiang, Ni; Huang, Yong

2018-05-01

Patterns of geographic variation in body size are predicted to evolve as adaptations to local environmental gradients. However, many of these clinal patterns in body size, such as Bergmann's rule, are controversial and require further investigation into ectotherms such as reptiles on a regional scale. To examine the environmental variables (temperature, precipitation, topography and primary productivity) that shaped patterns of geographic variation in body size in the reptile Calotes versicolor , we sampled 180 adult specimens (91 males and 89 females) at 40 locations across the species range in China. The MANOVA results suggest significant sexual size dimorphism in C. versicolor ( F 23,124  = 11.32, p  < .001). Our results showed that C. versicolor failed to fit the Bergmann's rule. We found that the most important predictors of variation in body size of C. versicolor differed for males and females, but mechanisms related to heat balance and water availability hypotheses were involved in both sexes. Temperature seasonality, precipitation of the driest month, precipitation seasonality, and precipitation of the driest quarter were the most important predictors of variation in body size in males, whereas mean precipitation of the warmest quarter, mean temperature of the wettest quarter, precipitation seasonality, and precipitation of the wettest month were most important for body size variation in females. The discrepancy between patterns of association between the sexes suggested that different selection pressures may be acting in males and females.

Geographical Clusters of Rape in the United States: 2000-2012

PubMed Central

Amin, Raid; Nabors, Nicole S.; Nelson, Arlene M.; Saqlain, Murshid; Kulldorff, Martin

2016-01-01

Background While rape is a very serious crime and public health problem, no spatial mapping has been attempted for rape on the national scale. This paper addresses the three research questions: (1) Are reported rape cases randomly distributed across the USA, after being adjusted for population density and age, or are there geographical clusters of reported rape cases? (2) Are the geographical clusters of reported rapes still present after adjusting for differences in poverty levels? (3) Are there geographical clusters where the proportion of reported rape cases that lead to an arrest is exceptionally low or exceptionally high? Methods We studied the geographical variation of reported rape events (2003-2012) and rape arrests (2000-2012) in the 48 contiguous states of the USA. The disease Surveillance software SaTScan™ with its spatial scan statistic is used to evaluate the spatial variation in rapes. The spatial scan statistic has been widely used as a geographical surveillance tool for diseases, and we used it to identify geographical areas with clusters of reported rape and clusters of arrest rates for rape. Results The spatial scan statistic was used to identify geographical areas with exceptionally high rates of reported rape. The analyses were adjusted for age, and in secondary analyses, for both age and poverty level. We also identified geographical areas with either a low or a high proportion of reported rapes leading to an arrest. Conclusions We have identified geographical areas with exceptionally high (low) rates of reported rape. The geographical problem areas identified are prime candidates for more intensive preventive counseling and criminal prosecution efforts by public health, social service, and law enforcement agencies Geographical clusters of high rates of reported rape are prime areas in need of expanded implementation of preventive measures, such as changing attitudes in our society toward rape crimes, in addition to having the criminal justice system play an even larger role in preventing rape. PMID:28078318

Geographical Clusters of Rape in the United States: 2000-2012.

PubMed

Amin, Raid; Nabors, Nicole S; Nelson, Arlene M; Saqlain, Murshid; Kulldorff, Martin

2015-01-01

While rape is a very serious crime and public health problem, no spatial mapping has been attempted for rape on the national scale. This paper addresses the three research questions: (1) Are reported rape cases randomly distributed across the USA, after being adjusted for population density and age, or are there geographical clusters of reported rape cases? (2) Are the geographical clusters of reported rapes still present after adjusting for differences in poverty levels? (3) Are there geographical clusters where the proportion of reported rape cases that lead to an arrest is exceptionally low or exceptionally high? We studied the geographical variation of reported rape events (2003-2012) and rape arrests (2000-2012) in the 48 contiguous states of the USA. The disease Surveillance software SaTScan™ with its spatial scan statistic is used to evaluate the spatial variation in rapes. The spatial scan statistic has been widely used as a geographical surveillance tool for diseases, and we used it to identify geographical areas with clusters of reported rape and clusters of arrest rates for rape. The spatial scan statistic was used to identify geographical areas with exceptionally high rates of reported rape. The analyses were adjusted for age, and in secondary analyses, for both age and poverty level. We also identified geographical areas with either a low or a high proportion of reported rapes leading to an arrest. We have identified geographical areas with exceptionally high (low) rates of reported rape. The geographical problem areas identified are prime candidates for more intensive preventive counseling and criminal prosecution efforts by public health, social service, and law enforcement agencies Geographical clusters of high rates of reported rape are prime areas in need of expanded implementation of preventive measures, such as changing attitudes in our society toward rape crimes, in addition to having the criminal justice system play an even larger role in preventing rape.

Complex watersheds, collaborative teams: Assessing pollutant presence and effects in the San Francisco Delta

EPA Science Inventory

There is a great diversity of sources of chemical contaminants and stressors over large geographic areas. Chemical contaminant inputs and magnitude can potentially exhibit wide seasonal variation over large geographic areas. Together, these factors make linking exposure to monito...

The cuticular hydrocarbons of the giant soil-burrowing cockroach Macropanesthia rhinoceros saussure (Blattodea: Blaberidae: Geoscapheinae): analysis with respect to age, sex and location.

PubMed

Brown, W V; Rose, H A; Lacey, M J; Wright, K

2000-11-01

The cuticular hydrocarbons of a widespread species of soil-burrowing cockroach, Macropanesthia rhinoceros, have been sampled from most of its known geographical locations. Analysis of extracts from individual insects has enabled a study of differences within a population as well as among geographical locations. In the case of M. rhinoceros, except for newly hatched first-instar nymphs, variations in hydrocarbon composition among individuals of different cohorts of M. rhinoceros, based on age and sex, are no greater than those among individuals of a single cohort. Geographical populations of this species are variable in hydrocarbon composition unless they occur within a few kilometres of each other. A few populations showed very different hydrocarbon patterns but, in the absence of any correlating biological differences, it is uncertain whether this signifies the presence of otherwise unrecognizable sibling species or just extreme examples of the geographical variation characteristic of this group of insects.

Mapping human genetic diversity in Asia.

PubMed

Abdulla, Mahmood Ameen; Ahmed, Ikhlak; Assawamakin, Anunchai; Bhak, Jong; Brahmachari, Samir K; Calacal, Gayvelline C; Chaurasia, Amit; Chen, Chien-Hsiun; Chen, Jieming; Chen, Yuan-Tsong; Chu, Jiayou; Cutiongco-de la Paz, Eva Maria C; De Ungria, Maria Corazon A; Delfin, Frederick C; Edo, Juli; Fuchareon, Suthat; Ghang, Ho; Gojobori, Takashi; Han, Junsong; Ho, Sheng-Feng; Hoh, Boon Peng; Huang, Wei; Inoko, Hidetoshi; Jha, Pankaj; Jinam, Timothy A; Jin, Li; Jung, Jongsun; Kangwanpong, Daoroong; Kampuansai, Jatupol; Kennedy, Giulia C; Khurana, Preeti; Kim, Hyung-Lae; Kim, Kwangjoong; Kim, Sangsoo; Kim, Woo-Yeon; Kimm, Kuchan; Kimura, Ryosuke; Koike, Tomohiro; Kulawonganunchai, Supasak; Kumar, Vikrant; Lai, Poh San; Lee, Jong-Young; Lee, Sunghoon; Liu, Edison T; Majumder, Partha P; Mandapati, Kiran Kumar; Marzuki, Sangkot; Mitchell, Wayne; Mukerji, Mitali; Naritomi, Kenji; Ngamphiw, Chumpol; Niikawa, Norio; Nishida, Nao; Oh, Bermseok; Oh, Sangho; Ohashi, Jun; Oka, Akira; Ong, Rick; Padilla, Carmencita D; Palittapongarnpim, Prasit; Perdigon, Henry B; Phipps, Maude Elvira; Png, Eileen; Sakaki, Yoshiyuki; Salvador, Jazelyn M; Sandraling, Yuliana; Scaria, Vinod; Seielstad, Mark; Sidek, Mohd Ros; Sinha, Amit; Srikummool, Metawee; Sudoyo, Herawati; Sugano, Sumio; Suryadi, Helena; Suzuki, Yoshiyuki; Tabbada, Kristina A; Tan, Adrian; Tokunaga, Katsushi; Tongsima, Sissades; Villamor, Lilian P; Wang, Eric; Wang, Ying; Wang, Haifeng; Wu, Jer-Yuarn; Xiao, Huasheng; Xu, Shuhua; Yang, Jin Ok; Shugart, Yin Yao; Yoo, Hyang-Sook; Yuan, Wentao; Zhao, Guoping; Zilfalil, Bin Alwi

2009-12-11

Asia harbors substantial cultural and linguistic diversity, but the geographic structure of genetic variation across the continent remains enigmatic. Here we report a large-scale survey of autosomal variation from a broad geographic sample of Asian human populations. Our results show that genetic ancestry is strongly correlated with linguistic affiliations as well as geography. Most populations show relatedness within ethnic/linguistic groups, despite prevalent gene flow among populations. More than 90% of East Asian (EA) haplotypes could be found in either Southeast Asian (SEA) or Central-South Asian (CSA) populations and show clinal structure with haplotype diversity decreasing from south to north. Furthermore, 50% of EA haplotypes were found in SEA only and 5% were found in CSA only, indicating that SEA was a major geographic source of EA populations.

Regional geographic variations in kidney cancer incidence rates in European countries.

PubMed

Li, Peng; Znaor, Ariana; Holcatova, Ivana; Fabianova, Eleonora; Mates, Dana; Wozniak, Magdalena B; Ferlay, Jacques; Scelo, Ghislaine

2015-06-01

Marked unexplained national variations in incidence rates of kidney cancer have been observed for decades in Europe. To investigate geographic variations at the regional level and identify European regions with high incidence rates of kidney cancer. Regional- and national-level incidence data were extracted from the Cancer Incidence in Five Continents databases, local cancer registry databases, and local published reports. World population age-standardised rates (ASRs) were calculated for the periods 2003-2007 and 1988-1992. Rates by period and sex were compared using map visualisation. During 2003-2007, the highest ASR was found in the Plzen region, Czech Republic (31.4/100,000 person-years in men). Other regions of the Czech Republic had ASRs of 18.6-27.5/100,000 in men, with a tendency for higher rates in regions south of Prague. Surrounding regions, including eastern Germany and regions of Slovakia and Austria, had medium-to-high incidence rates (13.0-16.8/100,000 in men). Three other areas in Europe showed higher incidence rates in men compared with the rest of the continent: Lithuania, Estonia, Latvia, and Belarus (15.0-17.6/100,000); Iceland (13.5/100,000), and northern Italy (up to 16.0/100,000). Similar regional differences were observed among women, with rates approximately half of those observed in men in the same region. In general, these regional geographic variations remained stable over the periods 1988-1992 and 2003-2007, although higher incidence rates were detected in the Baltic countries in 2003-2007. Several European regions show particularly high rates of kidney cancer incidence. Large variations were observed within countries covered by national health-care systems, implying that overdetection is not the major factor. We present regional geographic variations in kidney cancer incidence rates in Europe. We highlight several regions with high incidence rates where further studies should be conducted for cancer control and prevention. Copyright © 2014 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Wing morphometrics of Aedes (Ochlerotatus) albifasciatus (Macquart, 1838) (Diptera: Culicidae) from different climatic regions of Argentina.

PubMed

Garzón, Maximiliano J; Schweigmann, Nicolás

2018-05-16

Gene flow restrictions between populations of Aedes albifasciatus, the vector of Western equine encephalitis and Dirophilaria immitis, have been described in the central region of Argentina. Genetic and eco-physiological variations usually result in local forms reflecting the climatic regions. Mosquito wings and their different parts have ecological functions in flight and communication. Therefore, wing shape could be considered an aspect of sexual dimorphism, and its eco-physiological responses can be expressed as morphological changes induced by the environment. To compare the geographical and sexual variations with respect to wing shape and size in two Ae. albifasciatus populations from contrasting climates of Argentina (temperate: Buenos Aires, and the arid steppe of Patagonia: Sarmiento), the wings of adults reared in thermal trays at different constant temperatures (10-29 °C) were analyzed. The wing size of Ae. albifasciatus showed inverse linear relationships with the rearing thermal condition and higher slope for Buenos Aires. In the cool range (10-17 °C), geographical size variations responded to the converse Bergmann's rule, where Buenos Aires individuals were larger than those from Sarmiento. Sexual shape dimorphism occurred in both populations while geographical variation in shape was observed in both sexes. Buenos Aires individuals showed greater response sensitivity with respect to the size-temperature relation than those from Sarmiento. The converse Bergmann's rule in size variation could be due to a higher development rate in Sarmiento to produce more cohorts in the limited favorable season. The shape could be more relevant with respect to the size in the study of population structures due to the size being more liable to vary due to changes in the environment. The geographical variations with respect to morphology could be favored by the isolation between populations and adaptations to the environmental conditions. Our results demonstrate that the shape and size of wing provide useful phenotypic information for studies related to sexual and environmental adaptations.

Testing the Sensory Drive Hypothesis: Geographic variation in echolocation frequencies of Geoffroy's horseshoe bat (Rhinolophidae: Rhinolophus clivosus)

PubMed Central

Catto, Sarah; Mutumi, Gregory L.; Finger, Nikita; Webala, Paul W.

2017-01-01

Geographic variation in sensory traits is usually influenced by adaptive processes because these traits are involved in crucial life-history aspects including orientation, communication, lineage recognition and mate choice. Studying this variation can therefore provide insights into lineage diversification. According to the Sensory Drive Hypothesis, lineage diversification may be driven by adaptation of sensory systems to local environments. It predicts that acoustic signals vary in association with local climatic conditions so that atmospheric attenuation is minimized and transmission of the signals maximized. To test this prediction, we investigated the influence of climatic factors (specifically relative humidity and temperature) on geographic variation in the resting frequencies of the echolocation pulses of Geoffroy’s horseshoe bat, Rhinolophus clivosus. If the evolution of phenotypic variation in this lineage tracks climate variation, human induced climate change may lead to decreases in detection volumes and a reduction in foraging efficiency. A complex non-linear interaction between relative humidity and temperature affects atmospheric attenuation of sound and principal components composed of these correlated variables were, therefore, used in a linear mixed effects model to assess their contribution to observed variation in resting frequencies. A principal component composed predominantly of mean annual temperature (factor loading of -0.8455) significantly explained a proportion of the variation in resting frequency across sites (P < 0.05). Specifically, at higher relative humidity (around 60%) prevalent across the distribution of R. clivosus, increasing temperature had a strong negative effect on resting frequency. Climatic factors thus strongly influence acoustic signal divergence in this lineage, supporting the prediction of the Sensory Drive Hypothesis. The predicted future increase in temperature due to climate change is likely to decrease the detection volume in echolocating bats and adversely impact their foraging efficiency. PMID:29186147

Testing the Sensory Drive Hypothesis: Geographic variation in echolocation frequencies of Geoffroy's horseshoe bat (Rhinolophidae: Rhinolophus clivosus).

PubMed

Jacobs, David S; Catto, Sarah; Mutumi, Gregory L; Finger, Nikita; Webala, Paul W

2017-01-01

Geographic variation in sensory traits is usually influenced by adaptive processes because these traits are involved in crucial life-history aspects including orientation, communication, lineage recognition and mate choice. Studying this variation can therefore provide insights into lineage diversification. According to the Sensory Drive Hypothesis, lineage diversification may be driven by adaptation of sensory systems to local environments. It predicts that acoustic signals vary in association with local climatic conditions so that atmospheric attenuation is minimized and transmission of the signals maximized. To test this prediction, we investigated the influence of climatic factors (specifically relative humidity and temperature) on geographic variation in the resting frequencies of the echolocation pulses of Geoffroy's horseshoe bat, Rhinolophus clivosus. If the evolution of phenotypic variation in this lineage tracks climate variation, human induced climate change may lead to decreases in detection volumes and a reduction in foraging efficiency. A complex non-linear interaction between relative humidity and temperature affects atmospheric attenuation of sound and principal components composed of these correlated variables were, therefore, used in a linear mixed effects model to assess their contribution to observed variation in resting frequencies. A principal component composed predominantly of mean annual temperature (factor loading of -0.8455) significantly explained a proportion of the variation in resting frequency across sites (P < 0.05). Specifically, at higher relative humidity (around 60%) prevalent across the distribution of R. clivosus, increasing temperature had a strong negative effect on resting frequency. Climatic factors thus strongly influence acoustic signal divergence in this lineage, supporting the prediction of the Sensory Drive Hypothesis. The predicted future increase in temperature due to climate change is likely to decrease the detection volume in echolocating bats and adversely impact their foraging efficiency.

Environmental and genetic correlates of allocation to sexual reproduction in the circumpolar plant Bistorta vivipara.

PubMed

Bills, John W; Roalson, Eric H; Busch, Jeremiah W; Eidesen, Pernille B

2015-07-01

• Sexual reproduction often requires more energy and time than clonal reproduction. In marginal arctic conditions, species that can reproduce both sexually and clonally dominate. Plants with this capacity may thrive because they can alter reproduction depending on environmental conditions. Bistorta vivipara is a circumpolar herb that predominately reproduces clonally, but certain environmental conditions promote higher investment in flowers (and possible sexual reproduction). Despite largely reproducing clonally, the herb has high levels of genetic variation, and the processes underlying this paradoxical pattern of variation remain unclear. Here we identified environmental factors associated with sexual investment and examined whether sexual reproduction is associated with higher levels of genetic variation.• We sampled 20 populations of B. vivipara across the high Arctic archipelago of Svalbard. In each population, we measured reproductive traits, environmental variables, and collected samples for genetic analyses. These samples permitted hypotheses to be tested regarding sexual investment and ecological and genetic correlates.• Increased soil nitrogen and organic matter content and decreased elevation were positively associated with investment in flowers. Increased investment in flowers significantly correlated with more genotypes per population. Linkage disequilibrium was consistent with predominant clonality, but several populations showed higher genetic variation and lower differentiation than expected. There was no geographical genetic structure.• In B. vivipara, sexual investment is positively associated with habitat quality. Bistorta vivipara predominantly reproduces clonally, but occasional outcrossing, efficient clonal reproduction, and dispersal by bulbils can explain the considerable genetic variation and weak genetic structure in B. vivipara. © 2015 Botanical Society of America, Inc.

Geographic classification of hospitals: Alternative labor market areas

PubMed Central

De Lew, Nancy

1992-01-01

Medicare hospital payments are adjusted to reflect variation in hospital wages across geographic areas by grouping hospitals into labor market areas. By only recognizing the average wage in an area, Medicare encourages hospitals to contain costs. Labor market area definitions have recently received renewed attention because of their impact on hospital payments. Alternative labor market areas were evaluated using several criteria, including ability to explain wage variation and impact on payment equity. Rural labor market areas can be improved using county population size; however, further research on urban labor market areas is needed. PMID:10127453

32 CFR 1657.4 - Consideration of claims.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 6 2010-07-01 2010-07-01 false Consideration of claims. 1657.4 Section 1657.4 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM OVERSEAS... reclassification, by the board having geographic jurisdiction over his permanent address within the United States...

32 CFR 1657.4 - Consideration of claims.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 6 2011-07-01 2011-07-01 false Consideration of claims. 1657.4 Section 1657.4 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM OVERSEAS... reclassification, by the board having geographic jurisdiction over his permanent address within the United States...

32 CFR 1657.4 - Consideration of claims.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 6 2013-07-01 2013-07-01 false Consideration of claims. 1657.4 Section 1657.4 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM OVERSEAS... reclassification, by the board having geographic jurisdiction over his permanent address within the United States...

32 CFR 1657.4 - Consideration of claims.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 6 2012-07-01 2012-07-01 false Consideration of claims. 1657.4 Section 1657.4 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM OVERSEAS... reclassification, by the board having geographic jurisdiction over his permanent address within the United States...

32 CFR 1657.4 - Consideration of claims.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 6 2014-07-01 2014-07-01 false Consideration of claims. 1657.4 Section 1657.4 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM OVERSEAS... reclassification, by the board having geographic jurisdiction over his permanent address within the United States...

Comparable Wages, Inflation, and School Finance Equity

ERIC Educational Resources Information Center

Taylor, Lori L.

2006-01-01

A Comparable Wage Index (CWI) is an attractive mechanism for measuring geographic variations in the cost of education. A CWI measures uncontrollable variations in educator pay by observing systematic variations in the earnings of comparable workers who are not educators. Together, the 2000 census and the Occupational Employment Statistics survey…

Conservation genetics of bull trout: Geographic distribution of variation at microsatellite loci.

Treesearch

P. Spruell; A.R. Hemmingsen; P.J. Howell; N. Kanda; F.W. Allendorf

2003-01-01

We describe the genetic population structure of 65 bull trout (Salvelinus confluentus) populations from the northwestern United States using four microsatellite loci. The distribution of genetic variation as measured by microsatellites is consistent with previous allozyme and mitochondrial DNA analysis. There is relatively little genetic variation...

Water availability and environmental temperature correlate with geographic variation in water balance in common lizards.

PubMed

Dupoué, Andréaz; Rutschmann, Alexis; Le Galliard, Jean François; Miles, Donald B; Clobert, Jean; DeNardo, Dale F; Brusch, George A; Meylan, Sandrine

2017-12-01

Water conservation strategies are well documented in species living in water-limited environments, but physiological adaptations to water availability in temperate climate environments are still relatively overlooked. Yet, temperate species are facing more frequent and intense droughts as a result of climate change. Here, we examined variation in field hydration state (plasma osmolality) and standardized evaporative water loss rate (SEWL) of adult male and pregnant female common lizards (Zootoca vivipara) from 13 natural populations with contrasting air temperature, air humidity, and access to water. We found different patterns of geographic variation between sexes. Overall, males were more dehydrated (i.e. higher osmolality) than pregnant females, which likely comes from differences in field behaviour and water intake since the rate of SEWL was similar between sexes. Plasma osmolality and SEWL rate were positively correlated with environmental temperature in males, while plasma osmolality in pregnant females did not correlate with environmental conditions, reproductive stage or reproductive effort. The SEWL rate was significantly lower in populations without access to free standing water, suggesting that lizards can adapt or adjust physiology to cope with habitat dryness. Environmental humidity did not explain variation in water balance. We suggest that geographic variation in water balance physiology and behaviour should be taken account to better understand species range limits and sensitivity to climate change.

Seasonal and geographical variation in heat tolerance and evaporative cooling capacity in a passerine bird.

PubMed

Noakes, Matthew J; Wolf, Blair O; McKechnie, Andrew E

2016-03-01

Intraspecific variation in avian thermoregulatory responses to heat stress has received little attention, despite increasing evidence that endothermic animals show considerable physiological variation among populations. We investigated seasonal (summer versus winter) variation in heat tolerance and evaporative cooling in an Afrotropical ploceid passerine, the white-browed sparrow-weaver (Plocepasser mahali; ∼ 47 g) at three sites along a climatic gradient with more than 10 °C variation in mid-summer maximum air temperature (Ta). We measured resting metabolic rate (RMR) and total evaporative water loss (TEWL) using open flow-through respirometry, and core body temperature (Tb) using passive integrated transponder tags. Sparrow-weavers were exposed to a ramped profile of progressively higher Ta between 30 and 52 °C to elicit maximum evaporative cooling capacity (N=10 per site per season); the maximum Ta birds tolerated before the onset of severe hyperthermia (Tb ≈ 44 °C) was considered to be their hyperthermia threshold Ta (Ta,HT). Our data reveal significant seasonal acclimatisation of heat tolerance, with a desert population of sparrow-weavers reaching significantly higher Ta in summer (49.5 ± 1.4 °C, i.e. higher Ta,HT) than in winter (46.8 ± 0.9 °C), reflecting enhanced evaporative cooling during summer. Moreover, desert sparrow-weavers had significantly higher heat tolerance and evaporative cooling capacity during summer compared with populations from more mesic sites (Ta,HT=47.3 ± 1.5 and 47.6 ± 1.3 °C). A better understanding of the contributions of local adaptation versus phenotypic plasticity to intraspecific variation in avian heat tolerance and evaporative cooling capacity is needed for modelling species' responses to changing climates. © 2016. Published by The Company of Biologists Ltd.

Variation in the costs of delivering routine immunization services in Peru.

PubMed Central

Walker, D.; Mosqueira, N. R.; Penny, M. E.; Lanata, C. F.; Clark, A. D.; Sanderson, C. F. B.; Fox-Rushby, J. A.

2004-01-01

OBJECTIVE: Estimates of vaccination costs usually provide only point estimates at national level with no information on cost variation. In practice, however, such information is necessary for programme managers. This paper presents information on the variations in costs of delivering routine immunization services in three diverse districts of Peru: Ayacucho (a mountainous area), San Martin (a jungle area) and Lima (a coastal area). METHODS: We consider the impact of variability on predictions of cost and reflect on the likely impact on expected cost-effectiveness ratios, policy decisions and future research practice. All costs are in 2002 prices in US dollars and include the costs of providing vaccination services incurred by 19 government health facilities during the January-December 2002 financial year. Vaccine wastage rates have been estimated using stock records. FINDINGS: The cost per fully vaccinated child ranged from 16.63-24.52 U.S. Dollars in Ayacucho, 21.79-36.69 U.S. Dollars in San Martin and 9.58-20.31 U.S. Dollars in Lima. The volume of vaccines administered and wastage rates are determinants of the variation in costs of delivering routine immunization services. CONCLUSION: This study shows there is considerable variation in the costs of providing vaccines across geographical regions and different types of facilities. Information on how costs vary can be used as a basis from which to generalize to other settings and provide more accurate estimates for decision-makers who do not have disaggregated data on local costs. Future studies should include sufficiently large sample sizes and ensure that regions are carefully selected in order to maximize the interpretation of cost variation. PMID:15628205

Quantifying Geographic Variation in Health Care Outcomes in the United States before and after Risk-Adjustment.

PubMed

Rosenberg, Barry L; Kellar, Joshua A; Labno, Anna; Matheson, David H M; Ringel, Michael; VonAchen, Paige; Lesser, Richard I; Li, Yue; Dimick, Justin B; Gawande, Atul A; Larsson, Stefan H; Moses, Hamilton

2016-01-01

Despite numerous studies of geographic variation in healthcare cost and utilization at the local, regional, and state levels across the U.S., a comprehensive characterization of geographic variation in outcomes has not been published. Our objective was to quantify variation in US health outcomes in an all-payer population before and after risk-adjustment. We used information from 16 independent data sources, including 22 million all-payer inpatient admissions from the Healthcare Cost and Utilization Project (which covers regions where 50% of the U.S. population lives) to analyze 24 inpatient mortality, inpatient safety, and prevention outcomes. We compared outcome variation at state, hospital referral region, hospital service area, county, and hospital levels. Risk-adjusted outcomes were calculated after adjusting for population factors, co-morbidities, and health system factors. Even after risk-adjustment, there exists large geographical variation in outcomes. The variation in healthcare outcomes exceeds the well publicized variation in US healthcare costs. On average, we observed a 2.1-fold difference in risk-adjusted mortality outcomes between top- and bottom-decile hospitals. For example, we observed a 2.3-fold difference for risk-adjusted acute myocardial infarction inpatient mortality. On average a 10.2-fold difference in risk-adjusted patient safety outcomes exists between top and bottom-decile hospitals, including an 18.3-fold difference for risk-adjusted Central Venous Catheter Bloodstream Infection rates. A 3.0-fold difference in prevention outcomes exists between top- and bottom-decile counties on average; including a 2.2-fold difference for risk-adjusted congestive heart failure admission rates. The population, co-morbidity, and health system factors accounted for a range of R2 between 18-64% of variability in mortality outcomes, 3-39% of variability in patient safety outcomes, and 22-70% of variability in prevention outcomes. The amount of variability in health outcomes in the U.S. is large even after accounting for differences in population, co-morbidities, and health system factors. These findings suggest that: 1) additional examination of regional and local variation in risk-adjusted outcomes should be a priority; 2) assumptions of uniform hospital quality that underpin rationale for policy choices (such as narrow insurance networks or antitrust enforcement) should be challenged; and 3) there exists substantial opportunity for outcomes improvement in the US healthcare system.

Screening mammography among nursing home residents in the United States: Current guidelines and practice.

PubMed

Mack, Deborah S; Epstein, Mara M; Dubé, Catherine; Clark, Robin E; Lapane, Kate L

2018-06-04

United States (US) guidelines regarding when to stop routine breast cancer screening remain unclear. No national studies to-date have evaluated the use of screening mammography among US long-stay nursing home residents. This cross-sectional study was designed to identify prevalence, predictors, and geographic variation of screening mammography among that population in the context of current US guidelines. Screening mammography prevalence, identified with Physician/Supplier Part B claims and stratified by guideline age classification (65-74, ≥75 years), was estimated for all women aged ≥65 years residing in US Medicare- and Medicaid- certified nursing homes (≥1 year) with an annual Minimum Data Set (MDS) 3.0 assessment, continuous Medicare Part B enrollment, and no clinical indication for screening mammography as of 2011 (n = 389,821). The associations between resident- and regional- level factors, and screening mammography, were estimated by crude and adjusted prevalence ratios from robust Poisson regressions clustered by facility. Women on average were 85.4 (standard deviation ±8.1) years old, 77.9% were disabled, and 76.3% cognitively impaired. Screening mammography prevalence was 7.1% among those aged 65-74 years (95% Confidence Interval (CI): 6.8%-7.3%) and 1.7% among those ≥75 years (95% CI, 1.7%-1.8%), with geographic variation observed. Predictors of screening in both age groups included race, cognitive impairment, frailty, hospice, and some comorbidities. These results shed light on the current screening mammography practices in US nursing homes. Thoughtful consideration about individual screening recommendations and the implementation of more clear guidelines for this special population are warranted to prevent overscreening. Copyright © 2018 Elsevier Inc. All rights reserved.

How is post-industrial decline associated with the geography of physical activity? Evidence from the Health Survey for England.

PubMed

Rind, Esther; Jones, Andy; Southall, Humphrey

2014-03-01

In recent decades, the prevalence of physical activity has declined considerably in many developed countries, which has been related to rising levels of obesity and several weight-related medical conditions, such as coronary heart disease. There is evidence that areas exhibiting particularly low levels of physical activity have undergone a strong transition away from employment in physically demanding occupations. It is proposed that such processes of deindustrialisation may be causally linked to unexplained geographical disparities in physical activity. This study investigates how geographical variations in deindustrialisation are associated with current levels of physical activity across different activity domains and relevant macro-economic time periods in England. The analysis includes data on 27,414 adults from the Health Survey for England 2006 and 2008 who reported total, occupational, domestic, recreational and walking activity. Based on employment change in industries associated with heavy manual work, a local measurement of industrial decline was developed, covering the period 1841-2001. We applied a multilevel modelling approach to study associations between industrial decline and physical activity. Results indicate that the process of deindustrialisation appears to be associated with patterns of physical activity and that this is independent of household income. The effects observed were generally similar for men and women. However, the nature of the association differed across areas, time periods and employment types; in particular, residents of districts characterised by a history of manufacturing and mining employment had increased odds of reporting low activity levels. We conclude that post-industrial change may be a factor in explaining present-day variations in physical activity, emphasising the plausible impact of inherited cultures and regional identities on health related behaviours. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mitochondrial DNA regionalism and historical demography in the extant populations of Chirocephalus kerkyrensis (Branchiopoda: Anostraca).

PubMed

Ketmaier, Valerio; Marrone, Federico; Alfonso, Giuseppe; Paulus, Kirsten; Wiemann, Annika; Tiedemann, Ralph; Mura, Graziella

2012-01-01

Mediterranean temporary water bodies are important reservoirs of biodiversity and host a unique assemblage of diapausing aquatic invertebrates. These environments are currently vanishing because of increasing human pressure. Chirocephalus kerkyrensis is a fairy shrimp typical of temporary water bodies in Mediterranean plain forests and has undergone a substantial decline in number of populations in recent years due to habitat loss. We assessed patterns of genetic connectivity and phylogeographic history in the seven extant populations of the species from Albania, Corfu Is. (Greece), Southern and Central Italy. We analyzed sequence variation at two mitochondrial DNA genes (Cytochrome Oxidase I and 16s rRNA) in all the known populations of C. kerkyrensis. We used multiple phylogenetic, phylogeographic and coalescence-based approaches to assess connectivity and historical demography across the whole distribution range of the species. C. kerkyrensis is genetically subdivided into three main mitochondrial lineages; two of them are geographically localized (Corfu Is. and Central Italy) and one encompasses a wide geographic area (Albania and Southern Italy). Most of the detected genetic variation (≈81%) is apportioned among the aforementioned lineages. Multiple analyses of mismatch distributions consistently supported both past demographic and spatial expansions with the former predating the latter; demographic expansions were consistently placed during interglacial warm phases of the Pleistocene while spatial expansions were restricted to cold periods. Coalescence methods revealed a scenario of past isolation with low levels of gene flow in line with what is already known for other co-distributed fairy shrimps and suggest drift as the prevailing force in promoting local divergence. We recommend that these evolutionary trajectories should be taken in proper consideration in any effort aimed at protecting Mediterranean temporary water bodies.

Mitochondrial DNA Regionalism and Historical Demography in the Extant Populations of Chirocephalus kerkyrensis (Branchiopoda: Anostraca)

PubMed Central

Ketmaier, Valerio; Marrone, Federico; Alfonso, Giuseppe; Paulus, Kirsten; Wiemann, Annika; Tiedemann, Ralph; Mura, Graziella

2012-01-01

Background Mediterranean temporary water bodies are important reservoirs of biodiversity and host a unique assemblage of diapausing aquatic invertebrates. These environments are currently vanishing because of increasing human pressure. Chirocephalus kerkyrensis is a fairy shrimp typical of temporary water bodies in Mediterranean plain forests and has undergone a substantial decline in number of populations in recent years due to habitat loss. We assessed patterns of genetic connectivity and phylogeographic history in the seven extant populations of the species from Albania, Corfu Is. (Greece), Southern and Central Italy. Methodology/Principal Findings We analyzed sequence variation at two mitochondrial DNA genes (Cytochrome Oxidase I and 16s rRNA) in all the known populations of C. kerkyrensis. We used multiple phylogenetic, phylogeographic and coalescence-based approaches to assess connectivity and historical demography across the whole distribution range of the species. C. kerkyrensis is genetically subdivided into three main mitochondrial lineages; two of them are geographically localized (Corfu Is. and Central Italy) and one encompasses a wide geographic area (Albania and Southern Italy). Most of the detected genetic variation (≈81%) is apportioned among the aforementioned lineages. Conclusions/Significance Multiple analyses of mismatch distributions consistently supported both past demographic and spatial expansions with the former predating the latter; demographic expansions were consistently placed during interglacial warm phases of the Pleistocene while spatial expansions were restricted to cold periods. Coalescence methods revealed a scenario of past isolation with low levels of gene flow in line with what is already known for other co-distributed fairy shrimps and suggest drift as the prevailing force in promoting local divergence. We recommend that these evolutionary trajectories should be taken in proper consideration in any effort aimed at protecting Mediterranean temporary water bodies. PMID:22363417

Spatial distribution of podoconiosis in relation to environmental factors in Ethiopia: a historical review.

PubMed

Deribe, Kebede; Brooker, Simon J; Pullan, Rachel L; Hailu, Asrat; Enquselassie, Fikre; Reithinger, Richard; Newport, Melanie; Davey, Gail

2013-01-01

An up-to-date and reliable map of podoconiosis is needed to design geographically targeted and cost-effective intervention in Ethiopia. Identifying the ecological correlates of the distribution of podoconiosis is the first step for distribution and risk maps. The objective of this study was to investigate the spatial distribution and ecological correlates of podoconiosis using historical and contemporary survey data. Data on the observed prevalence of podoconiosis were abstracted from published and unpublished literature into a standardized database, according to strict inclusion and exclusion criteria. In total, 10 studies conducted between 1969 and 2012 were included, and data were available for 401,674 individuals older than 15 years of age from 229 locations. A range of high resolution environmental factors were investigated to determine their association with podoconiosis prevalence, using logistic regression. The prevalence of podoconiosis in Ethiopia was estimated at 3.4% (95% CI 3.3%-3.4%) with marked regional variation. We identified significant associations between mean annual Land Surface Temperature (LST), mean annual precipitation, topography of the land and fine soil texture and high prevalence of podoconiosis. The derived maps indicate both widespread occurrence of podoconiosis and a marked variability in prevalence of podoconiosis, with prevalence typically highest at altitudes >1500 m above sea level (masl), with >1500 mm annual rainfall and mean annual LST of 19-21°C. No (or very little) podoconiosis occurred at altitudes <1225 masl, with annual rainfall <900 mm, and mean annual LST of >24°C. Podoconiosis remains a public health problem in Ethiopia over considerable areas of the country, but exhibits marked geographical variation associated in part with key environmental factors. This is work in progress and the results presented here will be refined in future work.

Geographic Patterns of Radiology Referrals in the United States: A Descriptive Network Analysis.

PubMed

Liao, Geraldine J; Liao, Joshua M; Cook, Tessa S

2018-06-01

To provide a nationwide description of radiology referral patterns for Medicare beneficiaries and network-based measures that can describe and monitor shifts in referral patterns. We linked publicly available Medicare data with the National Plan and Provider Enumeration System data set to analyze 3,925,366 encounters representing referrals from nonradiology referrers to diagnostic radiology providers in 2015. We assessed per-state referral volume as well as in-state and in-region referrals and the correlation between state referral volume and in-state referrals. Additionally, we applied the conceptual framework of networks to create two measures to evaluate referrer-radiologist connections within each state: number of referrer relationships and referral density index (RDI). In 2015, there was considerable variation in in-state referrals across states, and the correlation between state referral volume and in-state referrals was low (0.18). Across census regions, in-region referrals were high (84.3% in the South to 89.2% in the Midwest). Across states, the mean number of referrer relationships ranged from 7.0 in Utah to 25.0 in California, and the number of referrer relationships varied significantly within states. Radiology provider RDI also varied both within and across states, with mean radiology provider RDI spanning from 0.05 in Kansas to 0.25 in Hawaii. In a nationwide description of geographic patterns in radiology referrals among Medicare beneficiaries, we demonstrate wide variation in radiology referral patterns and utilized network methods to develop two measures that can be used in the future to monitor shifts in referral patterns. Copyright © 2018 American College of Radiology. All rights reserved.

Intra-lake variation in maturity, fecundity, and spawning of slimy sculpins (Cottus cognatus) in southern Lake Ontario

USGS Publications Warehouse

Owens, Randall W.; Noguchi, George E.

1998-01-01

Knowledge of the spawning cycle and factors affecting fecundity of slimy sculpins (Cottus cognatus) are important in understanding the population dynamics of this species in large lake systems, like Lake Ontario. Fecundity and the spawning cycle of slimy sculpins were described from samples of slimy sculpins and their egg masses collected with bottom trawls during four annual surveys, April to October, 1988 to 1994. Incidence of gravid females and collections of their egg masses indicated that spawning by slimy sculpins likely occurred from late April to mid October in Lake Ontario. Protracted spawning by slimy sculpins in Lake Ontario is probably a function of the annual water temperature cycle at various depths. Mean length of gravid females was inversely related to density of slimy sculpins. Fecundity ranged from 55 to 1,157 eggs among fish 55 to 127 mm long, and for similar-sized fish, fecundity was inversely related to density of slimy sculpins. Fecundity was about 50% higher at Olcott, where population indices of slimy sculpins were low, compared with Nine Mile Point where indices were much higher. Somatic weight or total length were both good predictors of fecundity. Lipid content of slimy sculpins was lower in an area of high sculpin abundance than in an area of low sculpin abundance, suggesting that fecundity was a function of density-dependent food availability. In large aquatic ecosystems, samples from more than one area may be necessary to describe fecundity of a sedentary species like slimy sculpin, especially if fish densities vary considerably among geographic areas. Large geographic variations in fecundity may be an indicator of spatial imbalance of a species with its prey. Low fecundity may be a compensatory response to slimy sculpins to low food supplies, thereby limiting population growth.

Health System Resource Gaps and Associated Mortality from Pandemic Influenza across Six Asian Territories

PubMed Central

Rudge, James W.; Hanvoravongchai, Piya; Krumkamp, Ralf; Chavez, Irwin; Adisasmito, Wiku; Ngoc Chau, Pham; Phommasak, Bounlay; Putthasri, Weerasak; Shih, Chin-Shui; Stein, Mart; Timen, Aura; Touch, Sok; Reintjes, Ralf; Coker, Richard

2012-01-01

Background Southeast Asia has been the focus of considerable investment in pandemic influenza preparedness. Given the wide variation in socio-economic conditions, health system capacity across the region is likely to impact to varying degrees on pandemic mitigation operations. We aimed to estimate and compare the resource gaps, and potential mortalities associated with those gaps, for responding to pandemic influenza within and between six territories in Asia. Methods and Findings We collected health system resource data from Cambodia, Indonesia (Jakarta and Bali), Lao PDR, Taiwan, Thailand and Vietnam. We applied a mathematical transmission model to simulate a “mild-to-moderate” pandemic influenza scenario to estimate resource needs, gaps, and attributable mortalities at province level within each territory. The results show that wide variations exist in resource capacities between and within the six territories, with substantial mortalities predicted as a result of resource gaps (referred to here as “avoidable” mortalities), particularly in poorer areas. Severe nationwide shortages of mechanical ventilators were estimated to be a major cause of avoidable mortalities in all territories except Taiwan. Other resources (oseltamivir, hospital beds and human resources) are inequitably distributed within countries. Estimates of resource gaps and avoidable mortalities were highly sensitive to model parameters defining the transmissibility and clinical severity of the pandemic scenario. However, geographic patterns observed within and across territories remained similar for the range of parameter values explored. Conclusions The findings have important implications for where (both geographically and in terms of which resource types) investment is most needed, and the potential impact of resource mobilization for mitigating the disease burden of an influenza pandemic. Effective mobilization of resources across administrative boundaries could go some way towards minimizing avoidable deaths. PMID:22363739

Health system resource gaps and associated mortality from pandemic influenza across six Asian territories.

PubMed

Rudge, James W; Hanvoravongchai, Piya; Krumkamp, Ralf; Chavez, Irwin; Adisasmito, Wiku; Chau, Pham Ngoc; Phommasak, Bounlay; Putthasri, Weerasak; Shih, Chin-Shui; Stein, Mart; Timen, Aura; Touch, Sok; Reintjes, Ralf; Coker, Richard

2012-01-01

Southeast Asia has been the focus of considerable investment in pandemic influenza preparedness. Given the wide variation in socio-economic conditions, health system capacity across the region is likely to impact to varying degrees on pandemic mitigation operations. We aimed to estimate and compare the resource gaps, and potential mortalities associated with those gaps, for responding to pandemic influenza within and between six territories in Asia. We collected health system resource data from Cambodia, Indonesia (Jakarta and Bali), Lao PDR, Taiwan, Thailand and Vietnam. We applied a mathematical transmission model to simulate a "mild-to-moderate" pandemic influenza scenario to estimate resource needs, gaps, and attributable mortalities at province level within each territory. The results show that wide variations exist in resource capacities between and within the six territories, with substantial mortalities predicted as a result of resource gaps (referred to here as "avoidable" mortalities), particularly in poorer areas. Severe nationwide shortages of mechanical ventilators were estimated to be a major cause of avoidable mortalities in all territories except Taiwan. Other resources (oseltamivir, hospital beds and human resources) are inequitably distributed within countries. Estimates of resource gaps and avoidable mortalities were highly sensitive to model parameters defining the transmissibility and clinical severity of the pandemic scenario. However, geographic patterns observed within and across territories remained similar for the range of parameter values explored. The findings have important implications for where (both geographically and in terms of which resource types) investment is most needed, and the potential impact of resource mobilization for mitigating the disease burden of an influenza pandemic. Effective mobilization of resources across administrative boundaries could go some way towards minimizing avoidable deaths.

Disaggregating data on Asian American and Pacific Islander women to provide new insights on potential exposures to hazardous air pollutants in California.

PubMed

Quach, Thu; Liu, Ruiling; Nelson, David O; Hurley, Susan; Von Behren, Julie; Hertz, Andrew; Reynolds, Peggy

2014-11-01

The Asian American and Pacific Islander (AAPI) population is heterogeneous and rapidly growing in the United States, with a high proportion concentrated in California. Although traditionally assumed to have lower rates of breast cancer than non-Hispanic white women, recent studies have suggested considerable variation in incidence by AAPI ethnic group, with rates in some exceeding those in non-Hispanic whites. The potential role of environmental toxicants has not been well explored and may provide insights into these patterns. We created an exposure potential index (EPI) score for 24 hazardous air pollutants modeled by the U.S. Environmental Protection Agency National-Scale Air Toxics Assessment considered to be mammary gland carcinogens, and compared values at the census tract level for "geographically concentrated" AAPI groups throughout the State. "Geographically concentrated" populations were defined as census tracts with at least 100 individuals from a specified racial/ethnic population as enumerated by the 2000 Census. Although EPI scores differed little between census tracts with aggregated AAPI (mean EPI = 0.53) and non-Hispanic white women (mean EPI = 0.63), there was substantial variation between tracts for disaggregated AAPI groups, with notably higher EPI scores for tracts enumerated for Korean or Japanese women (mean EPI of 0.78 and 0.77, respectively) compared with other AAPI groups. Our findings underscore the importance of disaggregating data for the heterogeneous AAPI population to identify differences in potential environmental exposures across groups. Future cancer etiology studies should examine environmental exposure differences within and across groups for the diverse AAPI population. ©2014 American Association for Cancer Research.

Estimated effects of projected climate change on the basic reproductive number of the Lyme disease vector Ixodes scapularis.

PubMed

Ogden, Nicholas H; Radojevic, Milka; Wu, Xiaotian; Duvvuri, Venkata R; Leighton, Patrick A; Wu, Jianhong

2014-06-01

The extent to which climate change may affect human health by increasing risk from vector-borne diseases has been under considerable debate. We quantified potential effects of future climate change on the basic reproduction number (R0) of the tick vector of Lyme disease, Ixodes scapularis, and explored their importance for Lyme disease risk, and for vector-borne diseases in general. We applied observed temperature data for North America and projected temperatures using regional climate models to drive an I. scapularis population model to hindcast recent, and project future, effects of climate warming on R0. Modeled R0 increases were compared with R0 ranges for pathogens and parasites associated with variations in key ecological and epidemiological factors (obtained by literature review) to assess their epidemiological importance. R0 for I. scapularis in North America increased during the years 1971-2010 in spatio-temporal patterns consistent with observations. Increased temperatures due to projected climate change increased R0 by factors (2-5 times in Canada and 1.5-2 times in the United States), comparable to observed ranges of R0 for pathogens and parasites due to variations in strains, geographic locations, epidemics, host and vector densities, and control efforts. Climate warming may have co-driven the emergence of Lyme disease in northeastern North America, and in the future may drive substantial disease spread into new geographic regions and increase tick-borne disease risk where climate is currently suitable. Our findings highlight the potential for climate change to have profound effects on vectors and vector-borne diseases, and the need to refocus efforts to understand these effects.

Comparative Cytotoxicity of Glycyrrhiza glabra Roots from Different Geographical Origins Against Immortal Human Keratinocyte (HaCaT), Lung Adenocarcinoma (A549) and Liver Carcinoma (HepG2) Cells.

PubMed

Basar, Norazah; Oridupa, Olayinka Ayotunde; Ritchie, Kenneth J; Nahar, Lutfun; Osman, Nashwa Mostafa M; Stafford, Angela; Kushiev, Habibjon; Kan, Asuman; Sarker, Satyajit D

2015-06-01

Glycyrrhiza glabra L. (Fabaceae), commonly known as 'liquorice', is a well-known medicinal plant. Roots of this plant have long been used as a sweetening and flavouring agent in food and pharmaceutical products, and also as a traditional remedy for cough, upper and lower respiratory ailments, kidney stones, hepatitis C, skin disorder, cardiovascular diseases, diabetes, gastrointestinal ulcers and stomach ache. Previous pharmacological and clinical studies have revealed its antitussive, antiinflammatory, antiviral, antimicrobial, antioxidant, immunomodulatory, hepatoprotective and cardioprotective properties. While glycyrrhizin, a sweet-tasting triterpene saponin, is the principal bioactive compound, several bioactive flavonoids and isoflavonoids are also present in the roots of this plant. In the present study, the cytotoxicity of the methanol extracts of nine samples of the roots of G. glabra, collected from various geographical origins, was assessed against immortal human keratinocyte (HaCaT), lung adenocarcinoma (A549) and liver carcinoma (HepG2) cell lines using the in vitro 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazoliumbromide cell toxicity/viability assay. Considerable variations in levels of cytotoxicity were observed among various samples of G. glabra. Copyright © 2015 John Wiley & Sons, Ltd.

Population genomics of divergence among extreme and intermediate color forms in a polymorphic insect

USDA-ARS?s Scientific Manuscript database

Geographic variation in insect coloration is among the most intriguing examples of rapid phenotypic evolution and provides ideal opportunities to study the mechanisms of phenotypic change and diversification in closely related lineages. The bumble bee Bombus bifarius comprises two geographically dis...

Geographic variation in mixed-conifer forest fire regimes in California

Treesearch

Beaty R. Matthew; Taylor Alan H.

2008-01-01

This paper reviews recent research from California on geographic variability in mixed conifer(MC) forest fire regimes. MC forests are typically described as having experienced primarilyfrequent, low to moderate severity burns prior to fire suppression that created a mosaic ofvegetation patches with variable structure. Research...

Trends in Child Immunization across Geographical Regions in India: Focus on Urban-Rural and Gender Differentials

PubMed Central

Singh, Prashant Kumar

2013-01-01

Background Although child immunization is regarded as a highly cost-effective lifesaver, about fifty percent of the eligible children aged 12–23 months in India are without essential immunization coverage. Despite several programmatic initiatives, urban-rural and gender difference in child immunization pose an intimidating challenge to India’s public health agenda. This study assesses the urban-rural and gender difference in child immunization coverage during 1992–2006 across six major geographical regions in India. Data and Methods Three rounds of the National Family Health Survey (NFHS) conducted during 1992–93, 1998–99 and 2005–06 were analyzed. Bivariate analyses, urban-rural and gender inequality ratios, and the multivariate-pooled logistic regression model were applied to examine the trends and patterns of inequalities over time. Key Findings The analysis of change over one and half decades (1992–2006) shows considerable variations in child immunization coverage across six geographical regions in India. Despite a decline in urban-rural and gender differences over time, children residing in rural areas and girls remained disadvantaged. Moreover, northeast, west and south regions, which had the lowest gender inequality in 1992 observed an increase in gender difference over time. Similarly, urban-rural inequality increased in the west region during 1992–2006. Conclusion This study suggests periodic evaluation of the health care system is vital to assess the between and within group difference beyond average improvement. It is essential to integrate strong immunization systems with broad health systems and coordinate with other primary health care delivery programs to augment immunization coverage. PMID:24023816

The area level association between suicide, deprivation, social fragmentation and population density in the Republic of Ireland: a national study.

PubMed

O'Farrell, I B; Corcoran, P; Perry, I J

2016-06-01

Numerous studies have examined the ecological relationship between suicide and area level determinants such as deprivation and social fragmentation. In Ireland, there is considerable geographic variation in the rates of suicide. However, there is a dearth of Irish studies investigating the geographic variability of suicide. The Irish Central Statistics Office (CSO) provided data relating to all deaths by suicide and deaths of undetermined intent that occurred from 2009 to 2011. Negative binomial regression was used to examine the relationship between area level suicide rates and measures of deprivation, social fragmentation and population density that were taken from the 2011 National Census. Overall deprivation had the strongest independent effect on small-area rates of suicide, with the most deprived areas showing the greatest risk of suicide (risk ratio = 2.1; 95 % CI 1.70-2.52). Low population density (rurality) was associated with an increased risk suicide in males across both age groups and among females in the older 40-64-year age group. Conversely, a weak association between high population density (urbanicity) and increased suicide risk was found among females in the 15-39-year age group. Associations with social fragmentation only became apparent in the sub group analysis. Social fragmentation was associated with an elevated risk of suicide in the older 40-64 age group, with this effect being most pronounced among females. The findings of this study demonstrate marked geographical inequalities in the distribution of suicide in Ireland and highlight the importance of targeting suicide prevention resources in the most deprived areas.

Application of a random walk model to geographic distributions of animal mitochondrial DNA variation.

PubMed

Neigel, J E; Avise, J C

1993-12-01

In rapidly evolving molecules, such as animal mitochondrial DNA, mutations that delineate specific lineages may not be dispersed at sufficient rates to attain an equilibrium between genetic drift and gene flow. Here we predict conditions that lead to nonequilibrium geographic distributions of mtDNA lineages, test the robustness of these predictions and examine mtDNA data sets for consistency with our model. Under a simple isolation by distance model, the variance of an mtDNA lineage's geographic distribution is expected be proportional to its age. Simulation results indicated that this relationship is fairly robust. Analysis of mtDNA data from natural populations revealed three qualitative distributional patterns: (1) significant departure of lineage structure from equilibrium geographic distributions, a pattern exhibited in three rodent species with limited dispersal; (2) nonsignificant departure from equilibrium expectations, exhibited by two avian and two marine fish species with potentials for relatively long-distance dispersal; and (3) a progression from nonequilibrium distributions for younger lineages to equilibrium distributions for older lineages, a condition displayed by one surveyed avian species. These results demonstrate the advantages of considering mutation and genealogy in the interpretation of mtDNA geographic variation.

Significant variations in the cervical cancer screening rate in China by individual-level and geographical measures of socioeconomic status: a multilevel model analysis of a nationally representative survey dataset.

PubMed

Bao, Heling; Zhang, Lei; Wang, Limin; Zhang, Mei; Zhao, Zhenping; Fang, Liwen; Cong, Shu; Zhou, Maigeng; Wang, Linhong

2018-05-01

Variations in cervical cancer screening rates in China have rarely been studied in depth. This study aimed to investigate cervical cancer screening rates in relation to both individual-level and geographical measures of socioeconomic status (SES). Data were obtained from women aged 21 years or older by face-to-face interviews between August 2013 and July 2014 as part of the Chinese Chronic Diseases and Risk Factors Surveillance. The geographical variables were obtained from the 2010 Chinese population census. The cervical cancer screening rates and 95% confidence interval (CI) were estimated and mapped. Multilevel logistic regression models were fitted. Overall, only 21.4% (95% CI: 19.6-23.1%) of 91,816 women aged ≥21 years reported having ever been screened for cervical cancer and significant geographical variations at both province and county levels were identified (P < 0.01). The cervical cancer screening rates were the lowest among the poor [13.9% (95% CI: 12.1-15.7%)], uninsured [14.4% (95% CI: 10.3-18.4%)], less-educated [16.0% (95% CI: 14.3-17.6%)], and agricultural employment [18.1% (95% CI: 15.8-20.4%)] women along with those residing in areas of low economic status [15.0% (95% CI: 11.8-18.2%)], of low urbanization [15.6% (95% CI: 13.4-17.7%)], and of low education status [16.0% (95% CI: 14.0-18.1%)]. The multilevel analysis also indicated that women with lower individual-level measures of SES residing in areas with low geographical measures of SES were significantly less likely to receive cervical cancer screening (P < 0.0001). Despite the launch of an organized cancer screening program in China, cervical cancer screening rates remain alarmingly low and significant variations based on geographical regions and measures of SES still exist. It is therefore essential to adopt strategies to better direct limited available public resources to priority groups. © 2018 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

Student Perspectives on the Teaching of Geographical Information Systems (GIS) in Geography Degrees

ERIC Educational Resources Information Center

Seremet, Mehmet; Chalkley, Brian

2015-01-01

In an era when graduate employability is a key concern, the teaching of geographical information systems (GIS) has become a subject of considerable interest. This paper reports on a study of the GIS student learning experience using student survey data from six UK geography undergraduate programmes. The findings show that although students'…

Race, ethnicity, and state-by-state geographic variation in hemorrhagic stroke in dialysis patients.

PubMed

Wetmore, James B; Phadnis, Milind A; Mahnken, Jonathan D; Ellerbeck, Edward F; Rigler, Sally K; Zhou, Xinhua; Shireman, Theresa I

2014-04-01

Geographic variation in stroke rates is well established in the general population, with higher rates in the South than in other areas of the United States. A similar pattern of geographic variation in ischemic strokes has also recently been reported in patients undergoing long-term dialysis, but whether this is also the case for hemorrhagic stroke is unknown. Medicare claims from 2000 to 2005 were used to ascertain hemorrhagic stroke events in a large cohort of incident dialysis patients. A Poisson generalized linear mixed model was generated to determine factors associated with stroke and to ascertain state-by-state geographic variability in stroke rates by generating observed-to-expected (O/E) adjusted rate ratios (ARRs) for stroke. A total of 265,685 Medicare-eligible incident dialysis patients were studied. During a median follow-up of 15.5 months, 2397 (0.9%) patients sustained a hemorrhagic stroke. African Americans (ARR, 1.43; 95% confidence interval [CI], 1.30 to 1.57), Hispanics (ARR, 1.78; 95% CI, 1.57 to 2.03), and individuals of other races (ARR, 1.51; 95% CI, 1.26 to 1.80) had a significantly higher risk for hemorrhagic stroke compared with whites. In models adjusted for age and sex, four states had O/E ARRs for hemorrhagic stroke that were significantly greater than 1.0 (California, 1.15; Maryland, 1.25; North Carolina, 1.25; Texas, 1.19), while only 1 had an ARR less than 1.0 (Wisconsin, 0.79). However, after adjustment for race and ethnicity, no states had ARRs that varied significantly from 1.0. Race and ethnicity, or other factors that covary with these, appear to explain a substantial portion of state-by-state geographic variation in hemorrhagic stroke. This finding suggests that the factors underlying the high rate of hemorrhagic strokes in dialysis patients are likely to be system-wide and that further investigations into regional variations in clinical practices are unlikely to identify large opportunities for preventive interventions for this disorder.

Temperature fine-tunes Mediterranean Arabidopsis thaliana life-cycle phenology geographically.

PubMed

Marcer, A; Vidigal, D S; James, P M A; Fortin, M-J; Méndez-Vigo, B; Hilhorst, H W M; Bentsink, L; Alonso-Blanco, C; Picó, F X

2018-01-01

To understand how adaptive evolution in life-cycle phenology operates in plants, we need to unravel the effects of geographic variation in putative agents of natural selection on life-cycle phenology by considering all key developmental transitions and their co-variation patterns. We address this goal by quantifying the temperature-driven and geographically varying relationship between seed dormancy and flowering time in the annual Arabidopsis thaliana across the Iberian Peninsula. We used data on genetic variation in two major life-cycle traits, seed dormancy (DSDS50) and flowering time (FT), in a collection of 300 A. thaliana accessions from the Iberian Peninsula. The geographically varying relationship between life-cycle traits and minimum temperature, a major driver of variation in DSDS50 and FT, was explored with geographically weighted regressions (GWR). The environmentally varying correlation between DSDS50 and FT was analysed by means of sliding window analysis across a minimum temperature gradient. Maximum local adjustments between minimum temperature and life-cycle traits were obtained in the southwest Iberian Peninsula, an area with the highest minimum temperatures. In contrast, in off-southwest locations, the effects of minimum temperature on DSDS50 were rather constant across the region, whereas those of minimum temperature on FT were more variable, with peaks of strong local adjustments of GWR models in central and northwest Spain. Sliding window analysis identified a minimum temperature turning point in the relationship between DSDS50 and FT around a minimum temperature of 7.2 °C. Above this minimum temperature turning point, the variation in the FT/DSDS50 ratio became rapidly constrained and the negative correlation between FT and DSDS50 did not increase any further with increasing minimum temperatures. The southwest Iberian Peninsula emerges as an area where variation in life-cycle phenology appears to be restricted by the duration and severity of the hot summer drought. The temperature-driven varying relationship between DSDS50 and FT detected environmental boundaries for the co-evolution between FT and DSDS50 in A. thaliana. In the context of global warming, we conclude that A. thaliana phenology from the southwest Iberian Peninsula, determined by early flowering and deep seed dormancy, might become the most common life-cycle phenotype for this annual plant in the region. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

Life-history and ecological correlates of geographic variation in egg and clutch mass among passerine species

USGS Publications Warehouse

Martin, T.E.; Bassar, R.D.; Bassar, S.K.; Fontaine, J.J.; Lloyd, P.; Mathewson, Heather A.; Niklison, Alina M.; Chalfoun, A.

2006-01-01

Broad geographic patterns in egg and clutch mass are poorly described, and potential causes of variation remain largely unexamined. We describe interspecific variation in avian egg and clutch mass within and among diverse geographic regions and explore hypotheses related to allometry, clutch size, nest predation, adult mortality, and parental care as correlates and possible explanations of variation. We studied 74 species of Passeriformes at four latitudes on three continents: the north temperate United States, tropical Venezuela, subtropical Argentina, and south temperate South Africa. Egg and clutch mass increased with adult body mass in all locations, but differed among locations for the same body mass, demonstrating that egg and clutch mass have evolved to some extent independent of body mass among regions. A major portion of egg mass variation was explained by an inverse relationship with clutch size within and among regions, as predicted by life-history theory. However, clutch size did not explain all geographic differences in egg mass; eggs were smallest in South Africa despite small clutch sizes. These small eggs might be explained by high nest predation rates in South Africa; life-history theory predicts reduced reproductive effort under high risk of offspring mortality. This prediction was supported for clutch mass, which was inversely related to nest predation but not for egg mass. Nevertheless, clutch mass variation was not fully explained by nest predation, possibly reflecting interacting effects of adult mortality. Tests of the possible effects of nest predation on egg mass were compromised by limited power and by counterposing direct and indirect effects. Finally, components of parental investment, defined as effort per offspring, might be expected to positively coevolve. Indeed, egg mass, but not clutch mass, was greater in species that shared incubation by males and females compared with species in which only females incubate eggs. However, egg and clutch mass were not related to effort of parental care as measured by incubation attentiveness. Ecological and life-history correlates of egg and clutch mass variation found here follow from theory, but possible evolutionary causes deserve further study. ?? 2006 The Society for the Study of Evolution. All rights reserved.

Geographic Variations of Colorectal and Breast Cancer Late-Stage Diagnosis and the Effects of Neighborhood-Level Factors.

PubMed

Lin, Yan; Wimberly, Michael C

2017-04-01

The purpose of this study was to examine the geographic variations of late-stage diagnosis in colorectal cancer (CRC) and breast cancer as well as to investigate the effects of 3 neighborhood-level factors-socioeconomic deprivation, urban/rural residence, and spatial accessibility to health care-on the late-stage risks. This study used population-based South Dakota cancer registry data from 2001 to 2012. A total of 4,878 CRC cases and 6,418 breast cancer cases were included in the analyses. Two-level logistic regression models were used to analyze the risk of late-stage CRC and breast cancer. For CRC, there was a small geographic variation across census tracts in late-stage diagnosis, and residing in isolated small rural areas was significantly associated with late-stage risk. However, this association became nonsignificant after adjusting for census-tract level socioeconomic deprivation. Socioeconomic deprivation was an independent predictor of CRC late-stage risk, and it explained the elevated risk among American Indians. No relationship was found between spatial accessibility and CRC late-stage risk. For breast cancer, no geographic variation in the late-stage diagnosis was observed across census tracts, and none of the 3 neighborhood-level factors was significantly associated with late-stage risk. Results suggested that socioeconomic deprivation, rather than spatial accessibility, contributed to CRC late-stage risks in South Dakota as a rural state. CRC intervention programs could be developed to target isolated small rural areas, socioeconomically disadvantaged areas, as well as American Indians residing in these areas. © 2016 National Rural Health Association.

The role of poverty rate and racial distribution in the geographic clustering of breast cancer survival among older women: a geographic and multilevel analysis.

PubMed

Schootman, Mario; Jeffe, Donna B; Lian, Min; Gillanders, William E; Aft, Rebecca

2009-03-01

The authors examined disparities in survival among women aged 66 years or older in association with census-tract-level poverty rate, racial distribution, and individual-level factors, including patient-, treatment-, and tumor-related factors, utilization of medical care, and mammography use. They used linked data from the 1992-1999 Surveillance, Epidemiology, and End Results (SEER) programs, 1991-1999 Medicare claims, and the 1990 US Census. A geographic information system and advanced statistics identified areas of increased or reduced breast cancer survival and possible reasons for geographic variation in survival in 2 of the 5 SEER areas studied. In the Detroit, Michigan, area, one geographic cluster of shorter-than-expected breast cancer survival was identified (hazard ratio (HR) = 1.60). An additional area where survival was longer than expected approached statistical significance (HR = 0.4; P = 0.056). In the Atlanta, Georgia, area, one cluster of shorter- (HR = 1.81) and one cluster of longer-than-expected (HR = 0.72) breast cancer survival were identified. Stage at diagnosis and census-tract poverty (and patient's race in Atlanta) explained the geographic variation in breast cancer survival. No geographic clusters were identified in the 3 other SEER programs. Interventions to reduce late-stage breast cancer, focusing on areas of high poverty and targeting African Americans, may reduce disparities in breast cancer survival in the Detroit and Atlanta areas.

A Comparison of Autism Prevalence Trends in Denmark and Western Australia

ERIC Educational Resources Information Center

Parner, Erik T.; Thorsen, Poul; Dixon, Glenys; de Klerk, Nicholas; Leonard, Helen; Nassar, Natasha; Bourke, Jenny; Bower, Carol; Glasson, Emma J.

2011-01-01

Prevalence statistics for autism spectrum disorders (ASD) vary widely across geographical boundaries. Some variation can be explained by diagnostic methods, case ascertainment and age at diagnosis. This study compared prevalence statistics for two distinct geographical regions, Denmark and Western Australia, both of which have had population-based…

Geographic patterns of genetic variation and population structure in Pinus aristata, Rocky Mountain bristlecone pine

USDA-ARS?s Scientific Manuscript database

Pinus aristata Engelm., Rocky Mountain bristlecone pine, has a narrow core geographic and elevational distribution, occurs in disjunct populations and is threatened by multiple stresses, including rapid climate change, white pine blister rust, and bark beetles. Knowledge of genetic diversity and pop...

Landscape-scale geographic variations in microbial indices and labile phosphorus in Hapludults

USDA-ARS?s Scientific Manuscript database

Long-term soil and nutrient management practices can have lasting effects on the geographic distribution of soil microorganisms, function, and non-mobile nutrients such as phosphorus (P). The non-random redistribution can influence nutrient turnover rate and use efficiency of crops, in comparison to...

A review of geographic variation and Geographic Information Systems (GIS) applications in prescription drug use research.

PubMed

Wangia, Victoria; Shireman, Theresa I

2013-01-01

While understanding geography's role in healthcare has been an area of research for over 40 years, the application of geography-based analyses to prescription medication use is limited. The body of literature was reviewed to assess the current state of such studies to demonstrate the scale and scope of projects in order to highlight potential research opportunities. To review systematically how researchers have applied geography-based analyses to medication use data. Empiric, English language research articles were identified through PubMed and bibliographies. Original research articles were independently reviewed as to the medications or classes studied, data sources, measures of medication exposure, geographic units of analysis, geospatial measures, and statistical approaches. From 145 publications matching key search terms, forty publications met the inclusion criteria. Cardiovascular and psychotropic classes accounted for the largest proportion of studies. Prescription drug claims were the primary source, and medication exposure was frequently captured as period prevalence. Medication exposure was documented across a variety of geopolitical units such as countries, provinces, regions, states, and postal codes. Most results were descriptive and formal statistical modeling capitalizing on geospatial techniques was rare. Despite the extensive research on small area variation analysis in healthcare, there are a limited number of studies that have examined geographic variation in medication use. Clearly, there is opportunity to collaborate with geographers and GIS professionals to harness the power of GIS technologies and to strengthen future medication studies by applying more robust geospatial statistical methods. Copyright © 2013 Elsevier Inc. All rights reserved.

Hematologic and serum biochemical reference intervals for free-ranging common bottlenose dolphins (Tursiops truncatus) and variation in the distributions of clinicopathologic values related to geographic sampling site.

PubMed

Schwacke, Lori H; Hall, Ailsa J; Townsend, Forrest I; Wells, Randall S; Hansen, Larry J; Hohn, Aleta A; Bossart, Gregory D; Fair, Patricia A; Rowles, Teresa K

2009-08-01

To develop robust reference intervals for hematologic and serum biochemical variables by use of data derived from free-ranging bottlenose dolphins (Tursiops truncatus) and examine potential variation in distributions of clinicopathologic values related to sampling sites' geographic locations. 255 free-ranging bottlenose dolphins. Data from samples collected during multiple bottlenose dolphin capture-release projects conducted at 4 southeastern US coastal locations in 2000 through 2006 were combined to determine reference intervals for 52 clinicopathologic variables. A nonparametric bootstrap approach was applied to estimate 95th percentiles and associated 90% confidence intervals; the need for partitioning by length and sex classes was determined by testing for differences in estimated thresholds with a bootstrap method. When appropriate, quantile regression was used to determine continuous functions for 95th percentiles dependent on length. The proportion of out-of-range samples for all clinicopathologic measurements was examined for each geographic site, and multivariate ANOVA was applied to further explore variation in leukocyte subgroups. A need for partitioning by length and sex classes was indicated for many clinicopathologic variables. For each geographic site, few significant deviations from expected number of out-of-range samples were detected. Although mean leukocyte counts did not vary among sites, differences in the mean counts for leukocyte subgroups were identified. Although differences in the centrality of distributions for some variables were detected, the 95th percentiles estimated from the pooled data were robust and applicable across geographic sites. The derived reference intervals provide critical information for conducting bottlenose dolphin population health studies.

Few geographic and socioeconomic variations exist in primary total shoulder arthroplasty: a multi-level study of Australian registry data.

PubMed

Brennan-Olsen, Sharon L; Page, Richard S; Lane, Stephen E; Lorimer, Michelle; Buchbinder, Rachelle; Osborne, Richard H; Pasco, Julie A; Wluka, Anita E; Sanders, Kerrie M; Ebeling, Peter R; Graves, Stephen E

2016-07-16

Associations between socioeconomic position (SEP) and the uptake of primary total shoulder arthroplasty (TSA) is not well understood in the Australian population, thus potentially limiting equitable allocation of healthcare resources. We used the Australian Orthopaedic Association National Joint Replacement Registry (AOA NJRR) to examine whether geographic or socioeconomic variations exist in TSA performed for a diagnosis of osteoarthritis 2007-11 for all Australians aged ≥40 years. Primary anatomical and reverse TSA data were extracted from the AOA NJRR which captures >99 % of all TSA nationally. Residential addresses were cross-referenced to Australian Bureau of Statistics 2011 Census data to identify SEP measured at the area-level (categorised into deciles), and geographic location defined as Australian State/Territory of residence. We used a Poisson distribution for the number of TSA over the study period, and modelled the effects of age, SEP and geographic location using multilevel modelling. During 2007-11, we observed 6,123 TSA (62.2 % female). For both sexes, TSA showed a proportional increase with advancing age. TSA did not vary by SEP or geographic location, with the exception of greater TSA among men in New South Wales. Using a national registry approach we provide the first reliable picture of TSA at a national level. The uptake of TSA was equitable across SEP; however, there was some variation between the States/Territories. With an aging population, it is imperative that monitoring of major surgical procedures continues, and be focused toward determining whether TSA uptake correlates with need across different social and area-based groups.

Geographic patterns of seed mass are associated with climate factors, but relationships vary between species.

PubMed

Soper Gorden, Nicole L; Winkler, Katharine J; Jahnke, Matthew R; Marshall, Elizabeth; Horky, Joshua; Huddelson, Colton; Etterson, Julie R

2016-01-01

Seed size is a critical life history attribute with fitness effects that cascade throughout the lifespan of plants. Interspecific studies repeatedly report a negative correlation between seed mass and latitude. Yet, despite its importance, little is known about geographic variation in seed size within species' ranges. To improve our understanding of intraspecific geographic variation in seed size, we collected and weighed seeds by maternal line from 8 to 17 populations of seven herbaceous plant species spanning large geographic areas, and measured a dispersal trait, awn length, for two grass species. We examined the overall relationship between seed mass and latitude, then divided the data into species-specific subsets to compare the fit of three models to explain seed mass and awn length: (1) latitude and longitude, (2) long-term climate, and (3) collection-year weather. Like previous work, we found a negative relationship between interspecific seed mass and latitude. However, the best-fit models explaining seed size and awn length differed between individual species and often included significant interaction terms. For all species, the best model was either long-term or collection-year climate data instead of latitude and longitude. Intraspecific geographic patterns for seed traits were remarkably inconsistent, covarying both negatively and positively with temperature and precipitation. The only apparent generalization is that annual species' seed mass corresponded more with collection-year weather while perennial species covaried more with long-term climate. Overall, this study suggests that the scale of climate variation that molds seed traits is highly species-specific. © 2016 Botanical Society of America.

On geographic barriers and Pleistocene glaciations: Tracing the diversification of the Russet-crowned Warbler (Myiothlypis coronata) along the Andes

PubMed Central

2018-01-01

We studied the phylogeography and plumage variation of the Russet-crowned Warbler (Myiothlypis coronata), from Venezuela to Bolivia, with focus on populations from Ecuador and northern Peru. We analyzed sequences of mitochondrial and nuclear genes, geographic distributions, as well as photographs of specimens deposited at museum collections. Phylogenetic analyses identified three major lineages formed by populations from: Venezuela and Colombia (M. c. regulus), Ecuador and northern Peru (M. elata, M. castaneiceps, M. orientalis, M. c. chapmani), and central Peru and Bolivia (M. c. coronata). We found further population structure within M. c. regulus and M. c. coronata, and population structure and complexity of plumage variation within the Ecuador-northern Peru lineage. Time-calibrated trees estimated that most intraspecific variation originated during the Pleistocene; however, this pattern may not be attributed to an increase in diversification rate during that period. We discuss these results in the context of the importance of geographic-ecological barriers in promoting lineage diversification along the Andes and put forward a preliminary taxonomic proposal for major lineages identified in this study. PMID:29522515

Measuring the diffusion of linguistic change

PubMed Central

Nerbonne, John

2010-01-01

We examine situations in which linguistic changes have probably been propagated via normal contact as opposed to via conquest, recent settlement and large-scale migration. We proceed then from two simplifying assumptions: first, that all linguistic variation is the result of either diffusion or independent innovation, and, second, that we may operationalize social contact as geographical distance. It is clear that both of these assumptions are imperfect, but they allow us to examine diffusion via the distribution of linguistic variation as a function of geographical distance. Several studies in quantitative linguistics have examined this relation, starting with Séguy (Séguy 1971 Rev. Linguist. Romane 35, 335–357), and virtually all report a sublinear growth in aggregate linguistic variation as a function of geographical distance. The literature from dialectology and historical linguistics has mostly traced the diffusion of individual features, however, so that it is sensible to ask what sort of dynamic in the diffusion of individual features is compatible with Séguy's curve. We examine some simulations of diffusion in an effort to shed light on this question. PMID:21041207

Measuring the diffusion of linguistic change.

PubMed

Nerbonne, John

2010-12-12

We examine situations in which linguistic changes have probably been propagated via normal contact as opposed to via conquest, recent settlement and large-scale migration. We proceed then from two simplifying assumptions: first, that all linguistic variation is the result of either diffusion or independent innovation, and, second, that we may operationalize social contact as geographical distance. It is clear that both of these assumptions are imperfect, but they allow us to examine diffusion via the distribution of linguistic variation as a function of geographical distance. Several studies in quantitative linguistics have examined this relation, starting with Séguy (Séguy 1971 Rev. Linguist. Romane 35, 335-357), and virtually all report a sublinear growth in aggregate linguistic variation as a function of geographical distance. The literature from dialectology and historical linguistics has mostly traced the diffusion of individual features, however, so that it is sensible to ask what sort of dynamic in the diffusion of individual features is compatible with Séguy's curve. We examine some simulations of diffusion in an effort to shed light on this question.

Sub-Ethnic and Geographic Variations in Out-of-Pocket Private Health Insurance Premiums Among Mid-Life Asians.

PubMed

Choi, Sunha

2017-03-01

This study examined out-of-pocket premium burden of mid-life Asian Americans by comparing six sub-groups of Asians after controlling for geographic clustering at the county and state levels. The 2007-2011 National Health Interview Survey was linked to community-level data and analyzed for 4,628 Asians (ages 50-64), including 697 Asian Indians, 1,125 Chinese, 1,393 Filipinos, 434 Japanese, 524 Koreans, and 455 Vietnamese. Non-Hispanic Whites were included as a comparison group ( n = 48,135). Three-level multilevel modeling (state > county > individual) was conducted. Koreans and Vietnamese were found as vulnerable sub-groups considering their lower private health insurance rates and higher uninsured rates. Among those with private insurance, Asians, specifically Filipinos, paid significantly less than non-Hispanic Whites. Moderate but significant variations in the county- and state-level variance in out-of-pocket premiums were found, especially among mid-life Asians. This study demonstrates the importance of examining within-group heterogeneity and geographic variations in understanding premium burden among mid-life Asians.

On geographic barriers and Pleistocene glaciations: Tracing the diversification of the Russet-crowned Warbler (Myiothlypis coronata) along the Andes.

PubMed

Prieto-Torres, David A; Cuervo, Andrés M; Bonaccorso, Elisa

2018-01-01

We studied the phylogeography and plumage variation of the Russet-crowned Warbler (Myiothlypis coronata), from Venezuela to Bolivia, with focus on populations from Ecuador and northern Peru. We analyzed sequences of mitochondrial and nuclear genes, geographic distributions, as well as photographs of specimens deposited at museum collections. Phylogenetic analyses identified three major lineages formed by populations from: Venezuela and Colombia (M. c. regulus), Ecuador and northern Peru (M. elata, M. castaneiceps, M. orientalis, M. c. chapmani), and central Peru and Bolivia (M. c. coronata). We found further population structure within M. c. regulus and M. c. coronata, and population structure and complexity of plumage variation within the Ecuador-northern Peru lineage. Time-calibrated trees estimated that most intraspecific variation originated during the Pleistocene; however, this pattern may not be attributed to an increase in diversification rate during that period. We discuss these results in the context of the importance of geographic-ecological barriers in promoting lineage diversification along the Andes and put forward a preliminary taxonomic proposal for major lineages identified in this study.

Nuclear DNA contents of Echinchloa crus-galli and its Gaussian relationships with environments

NASA Astrophysics Data System (ADS)

Li, Dan-Dan; Lu, Yong-Liang; Guo, Shui-Liang; Yin, Li-Ping; Zhou, Ping; Lou, Yu-Xia

2017-02-01

Previous studies on plant nuclear DNA content variation and its relationships with environmental gradients produced conflicting results. We speculated that the relationships between nuclear DNA content of a widely-distributed species and its environmental gradients might be non-linear if it was sampled in a large geographical gradient. Echinochloa crus-galli (L.) P. Beauv. is a worldwide species, but without documents on its intraspecific variation of nuclear DNA content. Our objectives are: 1) to detect intraspecific variation scope of E. crus-galli in its nuclear DNA content, and 2) to testify whether nuclear DNA content of the species changes with environmental gradients following Gaussian models if its populations were sampled in a large geographical gradient. We collected seeds of 36 Chinese populations of E. crus-galli across a wide geographical gradient, and sowed them in a homogeneous field to get their offspring to determine their nuclear DNA content. We analyzed the relationships of nuclear DNA content of these populations with latitude, longitude, and nineteen bioclimatic variables by using Gaussian and linear models. (1) Nuclear DNA content varied from 2.113 to 2.410 pg among 36 Chinese populations of E. crus-galli, with a mean value of 2.256 pg. (2) Gaussian correlations of nuclear DNA content (y) with geographical gradients were detected, with latitude (x) following y = 2.2923*e -(x - 24.9360)2/2*63.79452 (r = 0.546, P < 0.001), and with longitude (x) following y = 2.2933*e -(x - 116.1801)2/2*44.74502 (r = 0.672, P < 0.001). (3) Among the nineteen bioclimatic variables, except temperature isothermality, precipitations of the wettest month, the wettest quarter and the warmest quarter, the others could be better fit with nuclear DNA content by using Gaussian models than by linear models. There exists intra-specific variation among 36 Chinese populations of E. crus-galli, Gaussian models could be applied to fit the correlations of its Nuclear DNA content with geographical and most bioclimatic gradients.

Pelage Variation and Distribution of the Black Lion Tamarin, Leontopithecus chrysopygus.

PubMed

Garbino, Guilherme Siniciato Terra; Rezende, Gabriela Cabral; Valladares-Padua, Claudio

2016-01-01

The black lion tamarin, Leontopithecus chrysopygus, is endemic to the Atlantic Forest of the interior of the state of São Paulo in Brazil. Since the discovery of the species, authors have described variations in the pelage of L. chrysopygus, but the nature of this variation has remained unknown. We examined museum specimens and living animals to see if the pelage of L. chrysopygus varies individually, geographically or ontogenetically. We reviewed all known locality records of the species, and concluded that the pelage of L. chrysopygus varies individually and ontogenetically, but not geographically. The extent of the golden chromogenetic fields is larger in younger individuals, and the pelage becomes darker after successive moults. We examined 2 juveniles that presented a pelage similar to adult L. caissara. Geographically, there is a clear break in the phenotypes attributed to L. caissara and L. chrysopygus, precluding clinal variation and corroborating the specific status of the former. The separation between these 2 species is coincident with a tectonic fault known as the 'Guapiara lineament', and may have been caused by a recent activation of this geological formation. We also suggest a historical contact zone between L. chrysopygus and the marmoset Callithrix aurita in the upper Rio Tietê region. © 2016 S. Karger AG, Basel.

Epstein-Barr virus strains and variations: Geographic or disease-specific variants?

PubMed

Neves, Marco; Marinho-Dias, Joana; Ribeiro, Joana; Sousa, Hugo

2017-03-01

The Epstein-Barr Virus (EBV) is associated with the development of several diseases, including infectious mononucleosis (IM), Burkitt's Lymphoma (BL), Nasopharyngeal Carcinoma, and other neoplasias. The publication of EBV genome 1984 led to several studies regarding the identification of different viral strains. Currently, EBV is divided into EBV type 1 (B95-8 strain) and EBV type 2 (AG876 strain), also known as type A and type B, which have been distinguished based upon genetic differences in the Epstein-Barr nuclear antigens (EBNAs) sequence. Several other EBV strains have been described in the past 10 years considering variations on EBV genome, and many have attempted to clarify if these variations are ethnic or geographically correlated, or if they are disease related. Indeed, there is an increasing interest to describe possible specific disease associations, with emphasis on different malignancies. These studies aim to clarify if these variations are ethnic or geographically correlated, or if they are disease related, thus being important to characterize the epidemiologic genetic distribution of EBV strains on our population. Here, we review the current knowledge on the different EBV strains and variants and its association with different diseases. J. Med. Virol. 89:373-387, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Whole Genome Sequencing demonstrates that Geographic Variation of Escherichia coli O157 Genotypes Dominates Host Association.

PubMed

Strachan, Norval J C; Rotariu, Ovidiu; Lopes, Bruno; MacRae, Marion; Fairley, Susan; Laing, Chad; Gannon, Victor; Allison, Lesley J; Hanson, Mary F; Dallman, Tim; Ashton, Philip; Franz, Eelco; van Hoek, Angela H A M; French, Nigel P; George, Tessy; Biggs, Patrick J; Forbes, Ken J

2015-10-07

Genetic variation in an infectious disease pathogen can be driven by ecological niche dissimilarities arising from different host species and different geographical locations. Whole genome sequencing was used to compare E. coli O157 isolates from host reservoirs (cattle and sheep) from Scotland and to compare genetic variation of isolates (human, animal, environmental/food) obtained from Scotland, New Zealand, Netherlands, Canada and the USA. Nei's genetic distance calculated from core genome single nucleotide polymorphisms (SNPs) demonstrated that the animal isolates were from the same population. Investigation of the Shiga toxin bacteriophage and their insertion sites (SBI typing) revealed that cattle and sheep isolates had statistically indistinguishable rarefaction profiles, diversity and genotypes. In contrast, isolates from different countries exhibited significant differences in Nei's genetic distance and SBI typing. Hence, after successful international transmission, which has occurred on multiple occasions, local genetic variation occurs, resulting in a global patchwork of continental and trans-continental phylogeographic clades. These findings are important for three reasons: first, understanding transmission and evolution of infectious diseases associated with multiple host reservoirs and multi-geographic locations; second, highlighting the relevance of the sheep reservoir when considering farm based interventions; and third, improving our understanding of why human disease incidence varies across the world.

Regional variations in the diversity and predicted metabolic potential of benthic prokaryotes in coastal northern Zhejiang, East China Sea

PubMed Central

Wang, Kai; Ye, Xiansen; Zhang, Huajun; Chen, Heping; Zhang, Demin; Liu, Lian

2016-01-01

Knowledge about the drivers of benthic prokaryotic diversity and metabolic potential in interconnected coastal sediments at regional scales is limited. We collected surface sediments across six zones covering ~200 km in coastal northern Zhejiang, East China Sea and combined 16 S rRNA gene sequencing, community-level metabolic prediction, and sediment physicochemical measurements to investigate variations in prokaryotic diversity and metabolic gene composition with geographic distance and under local environmental conditions. Geographic distance was the most influential factor in prokaryotic β-diversity compared with major environmental drivers, including temperature, sediment texture, acid-volatile sulfide, and water depth, but a large unexplained variation in community composition suggested the potential effects of unmeasured abiotic/biotic factors and stochastic processes. Moreover, prokaryotic assemblages showed a biogeographic provincialism across the zones. The predicted metabolic gene composition similarly shifted as taxonomic composition did. Acid-volatile sulfide was strongly correlated with variation in metabolic gene composition. The enrichments in the relative abundance of sulfate-reducing bacteria and genes relevant with dissimilatory sulfate reduction were observed and predicted, respectively, in the Yushan area. These results provide insights into the relative importance of geographic distance and environmental condition in driving benthic prokaryotic diversity in coastal areas and predict specific biogeochemically-relevant genes for future studies. PMID:27917954

Estimating cigarette tax avoidance and evasion: evidence from a national sample of littered packs

PubMed Central

Barker, Dianne C; Wang, Shu; Merriman, David; Crosby, Andrew; Resnick, Elissa A; Chaloupka, Frank J

2016-01-01

Introduction A number of recent studies document the proportion of all cigarette packs that are ‘contraband’ using discarded packs to measure tax avoidance and evasion, which we call tax non-compliance. To date, academic studies using discarded packs focused on relatively small geographical areas such as a city or a neighbourhood. Methods We visited 160 communities across 38 US states in 2012 and collected data from littered cigarette packs as part of the State and Community Tobacco Control (SCTC) Research Initiative and the Bridging the Gap Community Obesity Measures Project (BTG-COMP). Data collectors were trained in a previously tested littered pack data collection protocol. Results Field teams collected 2116 packs with cellophane across 132 communities. We estimate a national tax non-compliance rate of 18.5% with considerable variation across regions. Suburban areas had lower non-compliance than urban areas as well as areas with high and low median household income areas compared with middle income areas. Discussion We present the first academic national study of tax non-compliance using littered cigarette packs. We demonstrate the feasibility of meaningful large-scale data collection using this methodology and document considerable variation in tax non-compliance across areas, suggesting that both policy differences and geography may be important in control of illicit tobacco use. Given the geography of open borders among countries with varying tax rates, this simple methodology may be appropriate to estimate tax non-compliance in countries that use tax stamps or other pack markings, such as health warnings. PMID:27697946

Geographic variation in social acceptability of wildland fuels management in the western United States

USGS Publications Warehouse

Brunson, M.; Schindler, Bruce A.

2004-01-01

Contemporary natural resource management requires consideration of the social acceptability of management practices and conditions. Agencies wishing to measure, respond to, and influence social acceptability must understand the nuances of public perception regarding controversial issues. This study explores social acceptability judgments about one such issue: reduction of wildland fuel hazards on federal lands in the western United States. Citizens were surveyed in four locations where fire has been a significant ecological disturbance agent and public land agencies propose to reduce wildland fuel levels and wildfire hazards via prescribed burning, thinning, brush removal, and/or livestock grazing. Respondents in different locations differed in their knowledge about fire and fuel issues as well in their acceptability judgments. Differences are associated with location-specific social and environmental factors as well as individual beliefs. Results argue against using a??one-size-fits-alla?? policies or information strategies about fuels management.

The biological standard of living and mortality in Central Italy at the beginning of the 19th century.

PubMed

Coppola, Michela

2013-12-01

The biological standard of living in Central Italy at the beginning of the 19th century is analyzed using newly collected data on the height of recruits in the army of the Papal States. The results reveal a decline in height for the cohorts born under French rule (1796-1815). Although this trend was common to many parts of Europe, the estimated magnitude of the decline suggests a worsening of the biological standard of living of the working classes in the Papal States even relative to that of other countries. Despite the differences in the economic systems within the Papal States, no significant geographical variation in height has been found: even the most dynamic and advanced regions experienced a dramatic height decline. Mortality also increased during the period under consideration. Copyright © 2012 Elsevier B.V. All rights reserved.

Variability in imaging utilization in U.S. pediatric hospitals.

PubMed

Arnold, Ryan W; Graham, Dionne A; Melvin, Patrice R; Taylor, George A

2011-07-01

Use of medical imaging is under scrutiny because of rising costs and radiation exposure. We compare imaging utilization and costs across pediatric hospitals to determine their variability and potential determinants. Data were extracted from the Pediatric Health Information System (PHIS) database for all inpatient encounters from 40 U.S. children's hospitals. Imaging utilization and costs were compared by insurance type, geographical region, hospital size, severity of illness, length of stay and type of imaging, all among specific diagnoses. The hospital with the highest utilization performed more than twice as many imaging studies per patient as the hospital with the lowest utilization. Similarly, imaging costs ranged from $154 to $671/patient. Median imaging-utilization rate was 1.7 exams/patient on the ward and increased significantly in the PICU (11.8 exams/patient) and in the NICU (17.7 exams per patient, (P < 0.001). Considerable variability in imaging utilization persisted despite adjustment for case mix index (CMI, range in variation 16.6-25%). We found a significant correlation between imaging utilization and both CMI and length of stay, P < 0.0001). However, only 36% of the variation in imaging utilization could be explained by CMI. Diagnostic imaging utilization and costs vary widely in pediatric hospitals.

Time-series MODIS image-based retrieval and distribution analysis of total suspended matter concentrations in Lake Taihu (China).

PubMed

Zhang, Yuchao; Lin, Shan; Liu, Jianping; Qian, Xin; Ge, Yi

2010-09-01

Although there has been considerable effort to use remotely sensed images to provide synoptic maps of total suspended matter (TSM), there are limited studies on universal TSM retrieval models. In this paper, we have developed a TSM retrieval model for Lake Taihu using TSM concentrations measured in situ and a time series of quasi-synchronous MODIS 250 m images from 2005. After simple geometric and atmospheric correction, we found a significant relationship (R = 0.8736, N = 166) between in situ measured TSM concentrations and MODIS band normalization difference of band 3 and band 1. From this, we retrieved TSM concentrations in eight regions of Lake Taihu in 2007 and analyzed the characteristic distribution and variation of TSM. Synoptic maps of model-estimated TSM of 2007 showed clear geographical and seasonal variations. TSM in Central Lake and Southern Lakeshore were consistently higher than in other regions, while TSM in East Taihu was generally the lowest among the regions throughout the year. Furthermore, a wide range of TSM concentrations appeared from winter to summer. TSM in winter could be several times that in summer.

Genetic variation in the endangered Southwestern Willow Flycatcher

USGS Publications Warehouse

Busch, Joseph; Miller, Mark P.; Paxton, E.H.; Sogge, M.K.; Keim, Paul

2000-01-01

The Southwestern Willow Flycatcher (Empidonax traillii extimus) is an endangered Neotropical migrant that breeds in isolated remnants of dense riparian habitat in the southwestern United States. We estimated genetic variation at 20 breeding sites of the Southwestern Willow Flycatcher (290 individuals) using 38 amplified fragment length polymorphisms (AFLPs). Our results suggest that considerable genetic diversity exists within the subspecies and within local breeding sites. Statistical analyses of genetic variation revealed only slight, although significant, differentiation among breeding sites (Mantel's r = 0.0705, P < 0.0005; θ = 0.0816, 95% CI = 0.0608 to 0.1034; ΦST = 0.0458, P < 0.001). UPGMA cluster analysis of the AFLP markers indicates that extensive gene flow has occurred among breeding sites. No one site stood out as being genetically unique or isolated. Therefore, the small level of genetic structure that we detected may not be biologically significant. Ongoing field studies are consistent with this conclusion. Of the banded birds that were resighted or recaptured in Arizona during the 1996 to 1998 breeding seasons, one-third moved between breeding sites and two-thirds were philopatric. Low differentiation may be the result of historically high rangewide diversity followed by recent geographic isolation of breeding sites, although observational data indicate that gene flow is a current phenomenon. Our data suggest that breeding groups of E. t. extimus act as a metapopulation.

Recruitment variation of eastern Bering Sea crabs: Climate-forcing or top-down effects?

NASA Astrophysics Data System (ADS)

Zheng, Jie; Kruse, Gordon H.

2006-02-01

During the last three decades, population abundances of eastern Bering Sea (EBS) crab stocks fluctuated greatly, driven by highly variable recruitment. In recent years, abundances of these stocks have been very low compared to historical levels. This study aims to understand recruitment variation of six stocks of red king ( Paralithodes camtschaticus), blue king ( P. platypus), Tanner ( Chionoecetes bairdi), and snow ( C. opilio) crabs in the EBS. Most crab recruitment time series are not significantly correlated with each other. Spatial distributions of three broadly distributed crab stocks (EBS snow and Tanner crabs and Bristol Bay red king crab) have changed considerably over time, possibly related in part to the regime shift in climate and physical oceanography in 1976-1977. Three climate-forcing hypotheses on larval survival have been proposed to explain crab recruitment variation of Bristol Bay red king crab and EBS Tanner and snow crabs. Some empirical evidence supports speculation that groundfish predation may play an important role in crab recruitment success in the EBS. However, spatial dynamics in the geographic distributions of groundfish and crabs over time make it difficult to relate crab recruitment strength to groundfish biomass. Comprehensive field and spatially explicit modeling studies are needed to test the hypotheses and better understand the relative importance and compound effects of bottom-up and top-down controls on crab recruitment.

Will phenotypic plasticity affecting flowering phenology keep pace with climate change?

PubMed

Richardson, Bryce A; Chaney, Lindsay; Shaw, Nancy L; Still, Shannon M

2017-06-01

Rising temperatures have begun to shift flowering time, but it is unclear whether phenotypic plasticity can accommodate projected temperature change for this century. Evaluating clines in phenological traits and the extent and variation in plasticity can provide key information on assessing risk of maladaptation and developing strategies to mitigate climate change. In this study, flower phenology was examined in 52 populations of big sagebrush (Artemisia tridentata) growing in three common gardens. Flowering date (anthesis) varied 91 days from late July to late November among gardens. Mixed-effects modeling explained 79% of variation in flowering date, of which 46% could be assigned to plasticity and genetic variation in plasticity and 33% to genetics (conditional R 2  = 0.79, marginal R 2  = 0.33). Two environmental variables that explained the genetic variation were photoperiod and the onset of spring, the Julian date of accumulating degree-days >5 °C reaching 100. The genetic variation was mapped for contemporary and future climates (decades 2060 and 2090), showing flower date change varies considerably across the landscape. Plasticity was estimated to accommodate, on average, a ±13-day change in flowering date. However, the examination of genetic variation in plasticity suggests that the magnitude of plasticity could be affected by variation in the sensitivity to photoperiod and temperature. In a warmer common garden, lower-latitude populations have greater plasticity (+16 days) compared to higher-latitude populations (+10 days). Mapped climatypes of flowering date for contemporary and future climates illustrate the wide breadth of plasticity and large geographic overlap. Our research highlights the importance of integrating information on genetic variation, phenotypic plasticity and climatic niche modeling to evaluate plant responses and elucidate vulnerabilities to climate change. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

How important are determinants of obesity measured at the individual level for explaining geographic variation in body mass index distributions? Observational evidence from Canada using Quantile Regression and Blinder-Oaxaca Decomposition.

PubMed

Dutton, Daniel J; McLaren, Lindsay

2016-04-01

Obesity prevalence varies between geographic regions in Canada. The reasons for this variation are unclear but most likely implicate both individual-level and population-level factors. The objective of this study was to examine whether equalising correlates of body mass index (BMI) across these geographic regions could be reasonably expected to reduce differences in BMI distributions between regions. Using data from three cycles of the Canadian Community Health Survey (CCHS) 2001, 2003 and 2007 for males and females, we modelled between-region BMI cross-sectionally using quantile regression and Blinder-Oaxaca decomposition of the quantile regression results. We show that while individual-level variables (ie, age, income, education, physical activity level, fruit and vegetable consumption, smoking status, drinking status, family doctor status, rural status, employment in the past 12 months and marital status) may be Caucasian important correlates of BMI within geographic regions, those variables are not capable of explaining variation in BMI between regions. Equalisation of common correlates of BMI between regions cannot be reasonably expected to reduce differences in the BMI distributions between regions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Geographic variations of ecosystem service intensity in Fuzhou City, China.

PubMed

Hu, Xisheng; Hong, Wei; Qiu, Rongzu; Hong, Tao; Chen, Can; Wu, Chengzhen

2015-04-15

Ecosystem services are strongly influenced by the landscape configuration of natural and human systems. So they are heterogeneous across landscapes. However lack of the knowledge of spatial variations of ecosystem services constrains the effective management and conservation of ecosystems. We presented a spatially explicit and quantitative assessment of the geographic variations in ecosystem services for the Fuzhou City in 2009 using exploratory spatial data analysis (ESDA) and semivariance analysis. Results confirmed a significant and positive spatial autocorrelation, and revealed several hot-spots and cold-spots for the spatial distribution of ecosystem service intensity (ESI) in the study area. Also the trend surface analysis indicated that the level of ESI tended to be reduced gradually from north to south and from west to east, with a trough in the urban central area, which was quite in accordance with land-use structure. A more precise cluster map was then developed using the range of lag distance, deriving from semivariance analysis, as neighborhood size instead of default value in the software of ESRI ArcGIS 10.0, and geographical clusters where population growth and land-use pressure varied significantly and positively with ESI across the city were also created by geographically weighted regression (GWR). This study has good policy implications applicable to prioritize areas for conservation or construction, and design ecological corridor to improve ecosystem service delivery to benefiting areas. Copyright © 2015 Elsevier B.V. All rights reserved.

Multiple sclerosis: a geographical hypothesis.

PubMed

Carlyle, I P

1997-12-01

Multiple sclerosis remains a rare neurological disease of unknown aetiology, with a unique distribution, both geographically and historically. Rare in equatorial regions, it becomes increasingly common in higher latitudes; historically, it was first clinically recognized in the early nineteenth century. A hypothesis, based on geographical reasoning, is here proposed: that the disease is the result of a specific vitamin deficiency. Different individuals suffer the deficiency in separate and often unique ways. Evidence to support the hypothesis exists in cultural considerations, in the global distribution of the disease, and in its historical prevalence.

Spatial variation in messaging effects

NASA Astrophysics Data System (ADS)

Warshaw, Christopher

2018-05-01

There is large geographic variation in the public's views about climate change in the United States. Research now shows that climate messages can influence public beliefs about the scientific consensus on climate change, particularly in the places that are initially more skeptical.

Considerations of How to Study Learning Processes when Students Use GIS as an Instrument for Developing Spatial Thinking Skills

ERIC Educational Resources Information Center

Madsen, Lene Moller; Rump, Camilla

2012-01-01

Within the last 30 years, geographical information systems (GIS) have been used increasingly in the training of geographers. On the basis of the philosophy of technology and instrumental genesis, we sketch how the use of instruments interacts with learning processes and outline how this can be studied. We empirically analyse students' learning…

Spatial and temporal drivers of phenotypic diversity in polymorphic snakes.

PubMed

Cox, Christian L; Davis Rabosky, Alison R

2013-08-01

Color polymorphism in natural populations presents an ideal opportunity to study the evolutionary drivers of phenotypic diversity. Systems with striking spatial, temporal, and qualitative variation in color can be leveraged to study the mechanisms promoting the distribution of different types of variation in nature. We used the highly polymorphic ground snake (Sonora semiannulata), a putative coral snake mimic with both cryptic and conspicuous morphs, to compare patterns of neutral genetic variation and variation over space and time in color polymorphism to investigate the mechanistic drivers of phenotypic variation across scales. We found that strong selection promotes color polymorphism across spatial and temporal scales, with morph frequencies differing markedly between juvenile and adult age classes within a single population, oscillating over time within multiple populations, and varying drastically over the landscape despite minimal population genetic structure. However, we found no evidence that conspicuousness of morphs was related to which color pattern was favored by selection or to any geographic factors, including sympatry with coral snakes. We suggest that complex patterns of phenotypic variation in polymorphic systems may be a fundamental outcome of the conspicuousness of morphs and that explicit tests of temporal and geographic variation are critical to the interpretation of conspicuousness and mimicry.

Contrasting effects of landscape features on genetic structure in different geographic regions in the ornate dragon lizard, Ctenophorus ornatus.

PubMed

Levy, Esther; Tomkins, Joseph L; Lebas, Natasha R; Kennington, W Jason

2013-08-01

Habitat fragmentation can have profound effects on the distribution of genetic variation within and between populations. Previously, we showed that in the ornate dragon lizard, Ctenophorus ornatus, lizards residing on outcrops that are separated by cleared agricultural land are significantly more isolated and hold less genetic variation than lizards residing on neighbouring outcrops connected by undisturbed native vegetation. Here, we extend the fine-scale study to examine the pattern of genetic variation and population structure across the species' range. Using a landscape genetics approach, we test whether land clearing for agricultural purposes has affected the population structure of the ornate dragon lizard. We found significant genetic differentiation between outcrop populations (FST  = 0.12), as well as isolation by distance within each geographic region. In support of our previous study, land clearing was associated with higher genetic divergences between outcrops and lower genetic variation within outcrops, but only in the region that had been exposed to intense agriculture for the longest period of time. No other landscape features influenced population structure in any geographic region. These results show that the effects of landscape features can vary across species' ranges and suggest there may be a temporal lag in response to contemporary changes in land use. These findings therefore highlight the need for caution when assessing the impact of contemporary land use practices on genetic variation and population structure. © 2013 John Wiley & Sons Ltd.

Geographic structure of genetic variation in the widespread woodland grass Milium effusum L. A comparison between two regions with contrasting history and geomorphology.

PubMed

Tyler, Torbjörn

2002-12-01

Allozyme variation in the forest grass Milium effusum L. was studied in 21-23 populations within each of two equally sized densely sampled areas in northern and southern Sweden. In addition, 25 populations from other parts of Eurasia were studied for comparison. The structure of variation was analysed with both diversity statistics and measures based on allelic richness at a standardised sample size. The species was found to be highly variable, but no clear geographic patterns in the distribution of alleles or in overall genetic differentiation were found, either within the two regions or within the whole sample. Thus, no inferences about the direction of postglacial migration could be made. Obviously, migration and gene flow must have taken place in a manner capable of randomising the distribution of alleles. However, there were clear differences in levels and structuring of the variation between the two regions. Levels of variation, both in terms of genetic diversity and allelic richness, were lower in northern Sweden as compared with southern Sweden. In contrast, different measures of geographic structure all showed higher levels of population differentiation in the northern region. This is interpreted as due to different geomorphological conditions in the two regions, creating a relatively continuous habitat and gene flow in the southern region as compared with the northern region where the species, although common, is confined to narrow and mutually isolated corridors in the landscape.

Geographic variation within the military health system.

PubMed

Kimsey, Linda; Olaiya, Samuel; Smith, Chad; Hoburg, Andrew; Lipsitz, Stuart R; Koehlmoos, Tracey; Nguyen, Louis L; Weissman, Joel S

2017-04-13

This study seeks to quantify variation in healthcare utilization and per capita costs using system-defined geographic regions based on enrollee residence within the Military Health System (MHS). Data for fiscal years 2007 - 2010 were obtained from the Military Health System under a data sharing agreement with the Defense Health Agency (DHA). DHA manages all aspects of the Department of Defense Military Health System, including TRICARE. Adjusted rates were calculated for per capita costs and for two procedures with high interest to the MHS- back surgery and Cesarean sections for TRICARE Prime and Plus enrollees. Coefficients of variation (CoV) and interquartile ranges (IQR) were calculated and analyzed using residence catchment area as the geographic unit. Catchment areas anchored by a Military Treatment Facility (MTF) were compared to catchment areas not anchored by a MTF. Variation, as measured by CoV, was 0.37 for back surgery and 0.13 for C-sections in FY 2010- comparable to rates documented in other healthcare systems. The 2010 CoV (and average cost) for per capita costs was 0.26 ($3,479.51). Procedure rates were generally lower and CoVs higher in regions anchored by a MTF compared with regions not anchored by a MTF, based on both system-wide comparisons and comparisons of neighboring areas. In spite of its centrally managed system and relatively healthy beneficiaries with very robust health benefits, the MHS is not immune to unexplained variation in utilization and cost of healthcare.

Environmental Variables Explain Genetic Structure in a Beetle-Associated Nematode

PubMed Central

McGaughran, Angela; Morgan, Katy; Sommer, Ralf J.

2014-01-01

The distribution of a species is a complex expression of its ecological and evolutionary history and integrating population genetic, environmental, and ecological data can provide new insights into the effects of the environment on the population structure of species. Previous work demonstrated strong patterns of genetic differentiation in natural populations of the hermaphroditic nematode Pristionchus pacificus in its La Réunion Island habitat, but gave no clear understanding of the role of the environment in structuring this variation. Here, we present what is to our knowledge the first study to statistically evaluate the role of the environment in shaping the structure and distribution of nematode populations. We test the hypothesis that genetic structure in P. pacificus is influenced by environmental variables, by combining population genetic analyses of microsatellite data from 18 populations and 370 strains, with multivariate statistics on environmental data, and species distribution modelling. We assess and quantify the relative importance of environmental factors (geographic distance, altitude, temperature, precipitation, and beetle host) on genetic variation among populations. Despite the fact that geographic populations of P. pacificus comprise vast genetic diversity sourced from multiple ancestral lineages, we find strong evidence for local associations between environment and genetic variation. Further, we show that significantly more genetic variation in P. pacificus populations is explained by environmental variation than by geographic distances. This supports a strong role for environmental heterogeneity vs. genetic drift in the divergence of populations, which we suggest may be influenced by adaptive forces. PMID:24498073

Spatiotemporal variation of the association between climate dynamics and HFRS outbreaks in Eastern China during 2005-2016 and its geographic determinants

PubMed Central

Wu, Jiaping; Cazelles, Bernard; Qian, Quan; Mu, Di; Wang, Yong; Yin, Wenwu; Zhang, Wenyi

2018-01-01

Background Hemorrhagic fever with renal syndrome (HFRS) is a rodent-associated zoonosis caused by hantavirus. The HFRS was initially detected in northeast China in 1931, and since 1955 it has been detected in many regions of the country. Global climate dynamics influences HFRS spread in a complex nonlinear way. The quantitative assessment of the spatiotemporal variation of the “HFRS infections-global climate dynamics” association at a large geographical scale and during a long time period is still lacking. Methods and findings This work is the first study of a recently completed dataset of monthly HFRS cases in Eastern China during the period 2005–2016. A methodological synthesis that involves a time-frequency technique, a composite space-time model, hotspot analysis, and machine learning is implemented in the study of (a) the association between HFRS incidence spread and climate dynamics and (b) the geographic factors impacting this association over Eastern China during the period 2005–2016. The results showed that by assimilating core and city-specific knowledge bases the synthesis was able to depict quantitatively the space-time variation of periodic climate-HFRS associations at a large geographic scale and to assess numerically the strength of this association in the area and period of interest. It was found that the HFRS infections in Eastern China has a strong association with global climate dynamics, in particular, the 12, 18 and 36 mos periods were detected as the three main synchronous periods of climate dynamics and HFRS distribution. For the 36 mos period (which is the period with the strongest association), the space-time correlation pattern of the association strength indicated strong temporal but rather weak spatial dependencies. The generated space-time maps of association strength and association hotspots provided a clear picture of the geographic variation of the association strength that often-exhibited cluster characteristics (e.g., the south part of the study area displays a strong climate-HFRS association with non-point effects, whereas the middle-north part displays a weak climate-HFRS association). Another finding of this work is the upward climate-HFRS coherency trend for the past few years (2013–2015) indicating that the climate impacts on HFRS were becoming increasingly sensitive with time. Lastly, another finding of this work is that geographic factors affect the climate-HFRS association in an interrelated manner through local climate or by means of HFRS infections. In particular, location (latitude, distance to coastline and longitude), grassland and woodland are the geographic factors exerting the most noticeable effects on the climate-HFRS association (e.g., low latitude has a strong effect, whereas distance to coastline has a wave-like effect). Conclusions The proposed synthetic quantitative approach revealed important aspects of the spatiotemporal variation of the climate-HFRS association in Eastern China during a long time period, and identified the geographic factors having a major impact on this association. Both findings could improve public health policy in an HFRS-torn country like China. Furthermore, the synthetic approach developed in this work can be used to map the space-time variation of different climate-disease associations in other parts of China and the World. PMID:29874263

Geographic variation in prey preference in bark beetle predators

Treesearch

John D. Reeve; Brian L. Strom; Lynne K. Rieske; Bruce D. Ayers; Arnaud Costa

2009-01-01

1. Bark beetles and their predators are useful systems for addressing questions concerning diet breadth and prey preference in arthropod natural enemies. These predators use bark beetle pheromones to locate their prey, and the response todifferent pheromones is a measure of prey preference. 2. Trapping experiments were conducted to examine geographic...

Common mental disorders and the built environment in Santiago, Chile.

PubMed

Araya, Ricardo; Montgomery, Alan; Rojas, Graciela; Fritsch, Rosemarie; Solis, Jaime; Signorelli, Andres; Lewis, Glyn

2007-05-01

There is growing research interest in the influence of the built environment on mental disorders. To estimate the variation in the prevalence of common mental disorders attributable to individuals and the built environment of geographical sectors where they live. A sample of 3870 adults (response rate 90%) clustered in 248 geographical sectors participated in a household cross-sectional survey in Santiago, Chile. Independently rated contextual measures of the built environment were obtained. The Clinical Interview Schedule was used to estimate the prevalence of common mental disorders. There was a significant association between the quality of the built environment of small geographical sectors and the presence of common mental disorders among its residents. The better the quality of the built environment, the lower the scores for psychiatric symptoms; however, only a small proportion of the variation in common mental disorder existed at sector level, after adjusting for individual factors. Findings from our study, using a contextual assessment of the quality of the built environment and multilevel modelling in the analysis, suggest these associations may be more marked in non-Western settings with more homogeneous geographical sectors.

A comprehensive assessment of mercury exposure in penguin populations throughout the Southern Hemisphere: Using trophic calculations to identify sources of population-level variation.

PubMed

Brasso, Rebecka L; Chiaradia, André; Polito, Michael J; Raya Rey, Andrea; Emslie, Steven D

2015-08-15

The wide geographic distribution of penguins (Order Sphenisciformes) throughout the Southern Hemisphere provided a unique opportunity to use a single taxonomic group as biomonitors of mercury among geographically distinct marine ecosystems. Mercury concentrations were compared among ten species of penguins representing 26 geographically distinct breeding populations. Mercury concentrations were relatively low (⩽2.00ppm) in feathers from 18/26 populations considered. Population-level differences in trophic level explained variation in mercury concentrations among Little, King, and Gentoo penguin populations. However, Southern Rockhopper and Magellanic penguins breeding on Staten Island, Tierra del Fuego, had the highest mercury concentrations relative to their conspecifics despite foraging at a lower trophic level. The concurrent use of stable isotope and mercury data allowed us to document penguin populations at the greatest risk of exposure to harmful concentrations of mercury as a result of foraging at a high trophic level or in geographic 'hot spots' of mercury availability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Variation in susceptibility to oral infection with dengue viruses among geographic strains of Aedes aegypti.

PubMed

Gubler, D J; Nalim, S; Tan, R; Saipan, H; Sulianti Saroso, J

1979-11-01

The comparative susceptibility of 13 geographic strains of Aedes aegypti to oral infection with dengue viruses was studied by feeding the mosquitoes on a virus-erythrocyte-sugar suspension. Significant variation in susceptibility to four dengue serotypes was observed among the geographic strains tested. Mosquito strains which were more susceptible to one serotype were also more susceptible to the other serotypes, suggesting that the factors controlling susceptibility were the same for all types. The amount of virus required to infect mosquitoes orally varied inversely with the susceptibility of the geographic strain. Thresholds of infection were not the same for dengue types 1, 2, 3 and 4. There was no apparent difference in infectivity between prototype and recently isolated strains of dengue types 1 and 3. Crossing experimentibility as the resistant parent. No difference was observed between resistant and susceptible mosquito strains in the rate or the amount of viral replication after infection by the parenteral route, or in their ability to transmit dengue 2 virus after infection by the oral route.

Allozyme and RAPD Analysis of the Genetic Diversity and Geographic Variation in Wild Populations of the American Chestnut (Fagaceae)

Treesearch

Hongwen Huang; Fenny Dane; Thomas L. Kubisiak

1998-01-01

Genetic variation among 12 populations of the American chestnut (Custanea dentata) was investigated. Population genetic parameters estimated from allozyme variation suggest that C. dentata at both the population and species level has narrow genetic diversity as compared to other species in the genus. Average expected heterozygosity...

Variations in outcomes by residential location for women with breast cancer: a systematic review

PubMed Central

Dasgupta, Paramita; Youlden, Danny R; Garvey, Gail; Aitken, Joanne F; Wallington, Isabella; Chynoweth, Jennifer; Zorbas, Helen; Youl, Philippa H

2018-01-01

Objectives To systematically assess the evidence for variations in outcomes at each step along the breast cancer continuum of care for Australian women by residential location. Design Systematic review. Methods Systematic searches of peer-reviewed articles in English published from 1 January 1990 to 24 November 2017 using PubMed, EMBASE, CINAHL and Informit databases. Inclusion criteria were: population was adult female patients with breast cancer; Australian setting; outcome measure was survival, patient or tumour characteristics, screening rates or frequencies, clinical management, patterns of initial care or post-treatment follow-up with analysis by residential location or studies involving non-metropolitan women only. Included studies were critically appraised using a modified Newcastle–Ottawa Scale. Results Seventy-four quantitative studies met the inclusion criteria. Around 59% were considered high quality, 34% moderate and 7% low. No eligible studies examining treatment choices or post-treatment follow-up were identified. Non-metropolitan women consistently had poorer survival, with most of this differential being attributed to more advanced disease at diagnosis, treatment-related factors and socioeconomic disadvantage. Compared with metropolitan women, non-metropolitan women were more likely to live in disadvantaged areas and had differing clinical management and patterns of care. However, findings regarding geographical variations in tumour characteristics or diagnostic outcomes were inconsistent. Conclusions A general pattern of poorer survival and variations in clinical management for Australian female patients with breast cancer from non-metropolitan areas was evident. However, the wide variability in data sources, measures, study quality, time periods and geographical classification made direct comparisons across studies challenging. The review highlighted the need to promote standardisation of geographical classifications and increased comparability of data systems. It also identified key gaps in the existing literature including a lack of studies on advanced breast cancer, geographical variations in treatment choices from the perspective of patients and post-treatment follow-up. PMID:29706597

Health conditions and residential concentration of poverty: a study in Rio de Janeiro, Brazil

PubMed Central

Szwarcwald, C.; Bastos, F. I.; Barcellos, C.; Pina, M. d.; Esteves, M. A.

2000-01-01

STUDY OBJECTIVES—To establish the geographical relation of health conditions to socioeconomic status in the city of Rio de Janeiro, Brazil.
DESIGN—All reported deaths in the municipality of Rio de Janeiro, from 1987 to 1995, obtained from the Mortality Information System, were considered in the study. The 24 "administrative regions" that compose the city were used as the geographical units. A geographical information system (GIS) was used to link mortality data and population census data, and allowed the authors to establish the geographical pattern of the health indicators considered in this study: "infant mortality rate"; "standardised mortality rate"; "life expectancy" and "homicide rate". Information on location of low income communities (slums) was also provided by the GIS. A varimax rotation principal component analysis combined information on socioeconomic conditions and provided a two dimension basis to assess contextual variation.
MAIN RESULTS—The 24 administrative regions were aggregated into three different clusters, identified as relevant to reflect the socioeconomic variation. Almost all health indicator thematic maps showed the same socioeconomic stratification pattern. The worst health situation was found in the cluster composed of the harbour area and northern vicinity, precisely in the sector where the highest concentration of slum residents are present. This sector of the city exhibited an extremely high homicide rate and a seven year lower life expectancy than the remainder of the city. The sector that concentrates affluence, composed of the geographical units located along the coast, showed the best health situation. Intermediate health conditions were found in the west area, which also has poor living standards but low concentration of slums.
CONCLUSIONS—The findings suggest that social and organisation characteristics of low income communities may have a relevant role in understanding health variations. Local health and other social programmes specifically targeting these communities are recommended.


Keywords: geographical information system; health conditions; low income communities PMID:10846196

Geographic Mosaic of Plant Evolution: Extrafloral Nectary Variation Mediated by Ant and Herbivore Assemblages

PubMed Central

Nogueira, Anselmo; Rey, Pedro J.; Alcántara, Julio M.; Feitosa, Rodrigo M.; Lohmann, Lúcia G.

2015-01-01

Herbivory is an ecological process that is known to generate different patterns of selection on defensive plant traits across populations. Studies on this topic could greatly benefit from the general framework of the Geographic Mosaic Theory of Coevolution (GMT). Here, we hypothesize that herbivory represents a strong pressure for extrafloral nectary (EFN) bearing plants, with differences in herbivore and ant visitor assemblages leading to different evolutionary pressures among localities and ultimately to differences in EFN abundance and function. In this study, we investigate this hypothesis by analyzing 10 populations of Anemopaegma album (30 individuals per population) distributed through ca. 600 km of Neotropical savanna and covering most of the geographic range of this plant species. A common garden experiment revealed a phenotypic differentiation in EFN abundance, in which field and experimental plants showed a similar pattern of EFN variation among populations. We also did not find significant correlations between EFN traits and ant abundance, herbivory and plant performance across localities. Instead, a more complex pattern of ant–EFN variation, a geographic mosaic, emerged throughout the geographical range of A. album. We modeled the functional relationship between EFNs and ant traits across ant species and extended this phenotypic interface to characterize local situations of phenotypic matching and mismatching at the population level. Two distinct types of phenotypic matching emerged throughout populations: (1) a population with smaller ants (Crematogaster crinosa) matched with low abundance of EFNs; and (2) seven populations with bigger ants (Camponotus species) matched with higher EFN abundances. Three matched populations showed the highest plant performance and narrower variance of EFN abundance, representing potential plant evolutionary hotspots. Cases of mismatched and matched populations with the lowest performance were associated with abundant and highly detrimental herbivores. Our findings provide insights on the ecology and evolution of plant–ant guarding systems, and suggest new directions to research on facultative mutualistic interactions at wide geographic scales. PMID:25885221

Geographic Variation in Sexual Attraction of Spodoptera frugiperda Corn- and Rice-Strain Males to Pheromone Lures

PubMed Central

Unbehend, Melanie; Hänniger, Sabine; Vásquez, Gissella M.; Juárez, María Laura; Reisig, Dominic; McNeil, Jeremy N.; Meagher, Robert L.; Jenkins, David A.; Heckel, David G.; Groot, Astrid T.

2014-01-01

The corn- and rice-strains of Spodoptera frugiperda exhibit several genetic and behavioral differences and appear to be undergoing ecological speciation in sympatry. Previous studies reported conflicting results when investigating male attraction to pheromone lures in different regions, but this could have been due to inter-strain and/or geographic differences. Therefore, we investigated whether corn- and rice-strain males differed in their response to different synthetic pheromone blends in different regions in North America, the Caribbean and South America. All trapped males were strain-typed by two strain-specific mitochondrial DNA markers. In the first experiment, we found a nearly similar response of corn- and rice-strain males to two different 4-component blends, resembling the corn- and rice-strain female blend we previously described from females in Florida. This response showed some geographic variation in fields in Canada, North Carolina, Florida, Puerto Rico, and South America (Peru, Argentina). In dose-response experiments with the critical secondary sex pheromone component (Z)-7-dodecenyl acetate (Z7-12:OAc), we found some strain-specific differences in male attraction. While the response to Z7-12:OAc varied geographically in the corn-strain, rice-strain males showed almost no variation. We also found that the minor compound (Z)-11-hexadecenyl acetate (Z11-16:OAc) did not increase attraction of both strains in Florida and of corn-strain males in Peru. In a fourth experiment, where we added the stereo-isomer of the critical sex pheromone component, (E)-7-dodecenyl acetate, to the major pheromone component (Z)-9-tetradecenyl acetate (Z9-14:OAc), we found that this compound was attractive to males in North Carolina, but not to males in Peru. Overall, our results suggest that both strains show rather geographic than strain-specific differences in their response to pheromone lures, and that regional sexual communication differences might cause geographic differentiation between populations. PMID:24586634

Biofouling community composition across a range of environmental conditions and geographical locations suitable for floating marine renewable energy generation.

PubMed

Macleod, Adrian K; Stanley, Michele S; Day, John G; Cook, Elizabeth J

2016-01-01

Knowledge of biofouling typical of marine structures is essential for engineers to define appropriate loading criteria in addition to informing other stakeholders about the ecological implications of creating novel artificial environments. There is a lack of information regarding biofouling community composition (including weight and density characteristics) on floating structures associated with future marine renewable energy generation technologies. A network of navigation buoys were identified across a range of geographical areas, environmental conditions (tidal flow speed, temperature and salinity), and deployment durations suitable for future developments. Despite the perceived importance of environmental and temporal factors, geographical location explained the greatest proportion of the observed variation in community composition, emphasising the importance of considering geography when assessing the impact of biofouling on device functioning and associated ecology. The principal taxa associated with variation in biofouling community composition were mussels (Mytilus edulis), which were also important when determining loading criteria.

Variation in Payment Rates under Medicare's Inpatient Prospective Payment System.

PubMed

Krinsky, Sam; Ryan, Andrew M; Mijanovich, Tod; Blustein, Jan

2017-04-01

To measure variation in payment rates under Medicare's Inpatient Prospective Payment System (IPPS) and identify the main payment adjustments that drive variation. Medicare cost reports for all Medicare-certified hospitals, 1987-2013, and Dartmouth Atlas geographic files. We measure the Medicare payment rate as a hospital's total acute inpatient Medicare Part A payment, divided by the standard IPPS payment for its geographic area. We assess variation using several measures, both within local markets and nationally. We perform a factor decomposition to identify the share of variation attributable to specific adjustments. We also describe the characteristics of hospitals receiving different payment rates and evaluate changes in the magnitude of the main adjustments over time. Data downloaded from the Centers for Medicare and Medicaid Services, the National Bureau of Economic Research, and the Dartmouth Atlas. In 2013, Medicare paid for acute inpatient discharges at a rate 31 percent above the IPPS base. For the top 10 percent of discharges, the mean rate was double the IPPS base. Variations were driven by adjustments for medical education and care to low-income populations. The magnitude of variation has increased over time. Adjustments are a large and growing share of Medicare hospital payments, and they create significant variation in payment rates. © Health Research and Educational Trust.

Investigating human geographic origins using dual-isotope (87Sr/86Sr, δ18O) assignment approaches.

PubMed

Laffoon, Jason E; Sonnemann, Till F; Shafie, Termeh; Hofman, Corinne L; Brandes, Ulrik; Davies, Gareth R

2017-01-01

Substantial progress in the application of multiple isotope analyses has greatly improved the ability to identify nonlocal individuals amongst archaeological populations over the past decades. More recently the development of large scale models of spatial isotopic variation (isoscapes) has contributed to improved geographic assignments of human and animal origins. Persistent challenges remain, however, in the accurate identification of individual geographic origins from skeletal isotope data in studies of human (and animal) migration and provenance. In an attempt to develop and test more standardized and quantitative approaches to geographic assignment of individual origins using isotopic data two methods, combining 87Sr/86Sr and δ18O isoscapes, are examined for the Circum-Caribbean region: 1) an Interval approach using a defined range of fixed isotopic variation per location; and 2) a Likelihood assignment approach using univariate and bivariate probability density functions. These two methods are tested with enamel isotope data from a modern sample of known origin from Caracas, Venezuela and further explored with two archaeological samples of unknown origin recovered from Cuba and Trinidad. The results emphasize both the potential and limitation of the different approaches. Validation tests on the known origin sample exclude most areas of the Circum-Caribbean region and correctly highlight Caracas as a possible place of origin with both approaches. The positive validation results clearly demonstrate the overall efficacy of a dual-isotope approach to geoprovenance. The accuracy and precision of geographic assignments may be further improved by better understanding of the relationships between environmental and biological isotope variation; continued development and refinement of relevant isoscapes; and the eventual incorporation of a broader array of isotope proxy data.

Geographic variation in responses of European yellow dung flies to thermal stress.

PubMed

Bauerfeind, Stephanie S; Sørensen, Jesper G; Loeschcke, Volker; Berger, David; Broder, E Dale; Geiger, Madeleine; Ferrari, Manuela; Blanckenhorn, Wolf U

2018-04-01

Climatic conditions can be very heterogeneous even over small geographic scales, and are believed to be major determinants of the abundance and distribution of species and populations. Organisms are expected to evolve in response to the frequency and magnitude of local thermal extremes, resulting in local adaptation. Using replicate yellow dung fly (Scathophaga stercoraria; Diptera: Scathophagidae) populations from cold (northern Europe) and warm climates (southern Europe), we compared 1) responses to short-term heat and cold shocks in both sexes, 2) heat shock protein (Hsp70) expression in adults and eggs, and 3) female reproductive traits when facing short-term heat stress during egg maturation. Contrary to expectations, thermal traits showed minor geographic differentiation, with weak evidence for greater heat resistance of southern flies but no differentiation in cold resistance. Hsp70 protein expression was little affected by heat stress, indicating systemic rather than induced regulation of the heat stress response, possibly related to this fly group's preference for cold climes. In contrast, sex differences were pronounced: males (which are larger) endured hot temperatures longer, while females featured higher Hsp70 expression. Heat stress negatively affected various female reproductive traits, reducing first clutch size, overall reproductive investment, egg lipid content, and subsequent larval hatching. These responses varied little across latitude but somewhat among populations in terms of egg size, protein content, and larval hatching success. Several reproductive parameters, but not Hsp70 expression, exhibited heritable variation among full-sib families. Rather than large-scale clinal geographic variation, our study suggests some local geographic population differentiation in the ability of yellow dung flies to buffer the impact of heat stress on reproductive performance. Copyright © 2018 Elsevier Ltd. All rights reserved.

Time Trends and Geographic Variation in Use of Minimally Invasive Breast Biopsy

PubMed Central

Zimmermann, Christopher J.; Sheffield, Kristin M.; Duncan, Casey B.; Han, Yimei; Cooksley, Catherine D.; Townsend, Courtney M.; Riall, Taylor S.

2013-01-01

Background Current guidelines recommend minimally invasive breast biopsy (MIBB) as the “gold standard” for the diagnosis of breast lesions. The purpose of this study was to describe geographic patterns and time trends in the use of MIBB in Texas. Methods We used 100% Texas Medicare claims data (2000–2008) to identify women ≥66 years who underwent breast biopsy. Biopsies were classified as open or minimally invasive (MIBB). Time trends, racial/ethnic variation, and geographic variation in the use of biopsy techniques were examined. Results A total of 87,165 breast biopsies were performed on 75,518 breast masses in 67,582 women. 65.8% of the initial biopsies were MIBB. Radiologists performed 70.3% and surgeons 26.2% of MIBB. Surgeons performed 94.2% of open biopsies. Hispanic women were less likely to undergo MIBB (55.9%) compared to white (66.6%) and black (68.9%) women (p<0.0001). Women undergoing MIBB were also more likely to live in metropolitan areas and have higher income and educational levels (p<0.0001). The rate of MIBB increased from 44.4% in 2001 to 79.1% in 2008 (p<0.0001). There are clear geographic patterns in MIBB use with highest use near major cities. While rates are increasing overall, rates of improvement in the use of MIBB vary significantly across geographic regions and remain persistently low in more rural areas. Conclusion Despite an increase in the use of MIBB over time, MIBB use was consistently lower than recommended. We must identify specific barriers in rural areas to effectively change practice and achieve the statewide goal of 90% MIBB. PMID:23376029

[Temporal variation and geographical distribution: congenital heart defects in the Comunitat Valenciana].

PubMed

Cavero Carbonell, C; Zurriaga, O; Pérez Panadés, J; Barona Vilar, C; Martos Jiménez, C

2013-09-01

The objective of this study is to estimate the prevalence of congenital heart defects (CHD) in the Comunitat Valenciana (CV) in children less than one year old and identify whether there are temporal and geographic variations within this prevalence. The minimum basic data set from hospital discharge reports was used to select patients, who were born between 1999-2008, were less than one year old, and who lived in the CV with at least one hospital admission in which the primary diagnosis and/or any of the events were coded as CHD (codes 745-747 of the International Classification of Diseases 9th Revision Clinical Modification). The first hospital discharge report with CHD was selected, using the health card number to detect duplication. The prevalence and 95% confidence intervals were calculated, and the prevalence ratio (PR) and smoothed PR was obtained for each municipality to identify geographic patterns. In the period 1999-2008 there were 6.377 patients younger than one year with some CHD, representing the 43.2% of cases of congenital anomalies. The prevalence was 134.3 per 10.000 live births (95% CI: 131.1-137.6). There was a significant increase in the prevalence, from 115.8 in the 1999-2003 period to 149.5 in the 2004-2008 period. A higher risk was identified in the north of the CV, and in some municipalities of the province of Alicante, in the south. The observed increase in CHD agrees with the findings in other countries and it can be explained, at least in part, by improved diagnostic techniques. The geographic pattern identified requires a more detailed analysis that could explain the geographic variations found. Copyright © 2012 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

Heat Maps of Hypertension, Diabetes Mellitus, and Smoking in the Continental United States.

PubMed

Loop, Matthew Shane; Howard, George; de Los Campos, Gustavo; Al-Hamdan, Mohammad Z; Safford, Monika M; Levitan, Emily B; McClure, Leslie A

2017-01-01

Geographic variations in cardiovascular mortality are substantial, but descriptions of geographic variations in major cardiovascular risk factors have relied on data aggregated to counties. Herein, we provide the first description of geographic variation in the prevalence of hypertension, diabetes mellitus, and smoking within and across US counties. We conducted a cross-sectional analysis of baseline risk factor measurements and latitude/longitude of participant residence collected from 2003 to 2007 in the REGARDS study (Reasons for Geographic and Racial Differences in Stroke). Of the 30 239 participants, all risk factor measurements and location data were available for 28 887 (96%). The mean (±SD) age of these participants was 64.8(±9.4) years; 41% were black; 55% were female; 59% were hypertensive; 22% were diabetic; and 15% were current smokers. In logistic regression models stratified by race, the median(range) predicted prevalence of the risk factors were as follows: for hypertension, 49% (45%-58%) among whites and 72% (68%-78%) among blacks; for diabetes mellitus, 14% (10%-20%) among whites and 31% (28%-41%) among blacks; and for current smoking, 12% (7%-16%) among whites and 18% (11%-22%) among blacks. Hypertension was most prevalent in the central Southeast among whites, but in the west Southeast among blacks. Diabetes mellitus was most prevalent in the west and central Southeast among whites but in south Florida among blacks. Current smoking was most prevalent in the west Southeast and Midwest among whites and in the north among blacks. Geographic disparities in prevalent hypertension, diabetes mellitus, and smoking exist within states and within counties in the continental United States, and the patterns differ by race. © 2017 American Heart Association, Inc.

Genetic and environmental factors affecting birth size variation: a pooled individual-based analysis of secular trends and global geographical differences using 26 twin cohorts.

PubMed

Yokoyama, Yoshie; Jelenkovic, Aline; Hur, Yoon-Mi; Sund, Reijo; Fagnani, Corrado; Stazi, Maria A; Brescianini, Sonia; Ji, Fuling; Ning, Feng; Pang, Zengchang; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Rebato, Esther; Hopper, John L; Cutler, Tessa L; Saudino, Kimberly J; Nelson, Tracy L; Whitfield, Keith E; Corley, Robin P; Huibregtse, Brooke M; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth J F; Llewellyn, Clare H; Fisher, Abigail; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Bartels, Meike; van Beijsterveldt, Catharina E M; Willemsen, Gonneke; Harris, Jennifer R; Brandt, Ingunn; Nilsen, Thomas S; Craig, Jeffrey M; Saffery, Richard; Dubois, Lise; Boivin, Michel; Brendgen, Mara; Dionne, Ginette; Vitaro, Frank; Haworth, Claire M A; Plomin, Robert; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Rasmussen, Finn; Tynelius, Per; Tarnoki, Adam D; Tarnoki, David L; Ooki, Syuichi; Rose, Richard J; Pietiläinen, Kirsi H; Sørensen, Thorkild I A; Boomsma, Dorret I; Kaprio, Jaakko; Silventoinen, Karri

2018-05-19

The genetic architecture of birth size may differ geographically and over time. We examined differences in the genetic and environmental contributions to birthweight, length and ponderal index (PI) across geographical-cultural regions (Europe, North America and Australia, and East Asia) and across birth cohorts, and how gestational age modifies these effects. Data from 26 twin cohorts in 16 countries including 57 613 monozygotic and dizygotic twin pairs were pooled. Genetic and environmental variations of birth size were estimated using genetic structural equation modelling. The variance of birthweight and length was predominantly explained by shared environmental factors, whereas the variance of PI was explained both by shared and unique environmental factors. Genetic variance contributing to birth size was small. Adjusting for gestational age decreased the proportions of shared environmental variance and increased the propositions of unique environmental variance. Genetic variance was similar in the geographical-cultural regions, but shared environmental variance was smaller in East Asia than in Europe and North America and Australia. The total variance and shared environmental variance of birth length and PI were greater from the birth cohort 1990-99 onwards compared with the birth cohorts from 1970-79 to 1980-89. The contribution of genetic factors to birth size is smaller than that of shared environmental factors, which is partly explained by gestational age. Shared environmental variances of birth length and PI were greater in the latest birth cohorts and differed also across geographical-cultural regions. Shared environmental factors are important when explaining differences in the variation of birth size globally and over time.

Geographical trends in the yolk carotenoid composition of the pied flycatcher (Ficedula hypoleuca).

PubMed

Eeva, Tapio; Ruuskanen, Suvi; Salminen, Juha-Pekka; Belskii, Eugen; Järvinen, Antero; Kerimov, Anvar; Korpimäki, Erkki; Krams, Indrikis; Moreno, Juan; Morosinotto, Chiara; Mänd, Raivo; Orell, Markku; Qvarnström, Anna; Siitari, Heli; Slater, Fred M; Tilgar, Vallo; Visser, Marcel E; Winkel, Wolfgang; Zang, Herwig; Laaksonen, Toni

2011-02-01

Carotenoids in the egg yolks of birds are considered to be important antioxidants and immune stimulants during the rapid growth of embryos. Yolk carotenoid composition is strongly affected by the carotenoid composition of the female's diet at the time of egg formation. Spatial and temporal differences in carotenoid availability may thus be reflected in yolk concentrations. To assess whether yolk carotenoid concentrations or carotenoid profiles show any large-scale geographical trends or differences among habitats, we collected yolk samples from 16 European populations of the pied flycatcher, Ficedula hypoleuca. We found that the concentrations and proportions of lutein and some other xanthophylls in the egg yolks decreased from Central Europe northwards. The most southern population (which is also the one found at the highest altitude) also showed relatively low carotenoid levels. Concentrations of β-carotene and zeaxanthin did not show any obvious geographical gradients. Egg yolks also contained proportionally more lutein and other xanthophylls in deciduous than in mixed or coniferous habitats. We suggest that latitudinal gradients in lutein and xanthophylls reflect the lower availability of lutein-rich food items in the northern F. hypoleuca populations and in montane southern populations, which start egg-laying earlier relative to tree phenology than the Central European populations. Similarly, among-habitat variation is likely to reflect the better availability of lutein-rich food in deciduous forests. Our study is the first to indicate that the concentration and profile of yolk carotenoids may show large-scale spatial variation among populations in different parts of the species' geographical range. Further studies are needed to test the fitness effects of this geographical variation.

Geographic and phenotypic variation in heartwood and essential-oil characters in natural populations of Santalum austrocaledonicum in Vanuatu.

PubMed

Page, Tony; Southwell, Ian; Russell, Mike; Tate, Hanington; Tungon, Joseph; Sam, Chanel; Dickinson, Geoff; Robson, Ken; Leakey, Roger R B

2010-08-01

Phenotypic variation in heartwood and essential-oil characters of Santalum austrocaledonicum was assessed across eleven populations on seven islands of Vanuatu. Trees differed significantly in their percentage heartwood cross-sectional area and this varied independently of stem diameter. The concentrations of the four major essential-oil constituents (alpha-santalol, beta-santalol, (Z)-beta-curcumen-12-ol, and cis-nuciferol) of alcohol-extracted heartwood exhibited at least tenfold and continuous tree-to-tree variation. Commercially important components alpha- and beta-santalol found in individual trees ranged from 0.8-47% and 0-24.1%, respectively, across all populations, and significant (P<0.05) differences for each were found between individual populations. The Erromango population was unique in that the mean concentrations of its monocyclic ((Z)-beta-curcumen-12-ol and cis-nuciferol) sesquiterpenes exceeded those of its bi- and tricyclic (alpha- and beta-santalol) sesquiterpenes. Heartwood colour varied between trees and spanned 65 colour categories, but no identifiable relationships were found between heartwood colour and alpha- and beta-santalol, although a weak relationship was evident between colour saturation and total oil concentration. These results indicate that the heartwood colour is not a reliable predictive trait for oil quality. The results of this study highlight the knowledge gaps in fundamental understanding of heartwood biology in Santalum genus. The intraspecific variation in heartwood cross-sectional area, oil concentration, and oil quality traits is of considerable importance to the domestication of sandalwood and present opportunities for the development of highly superior S. austrocaledonicum cultivars that conform to the industry's International Standards used for S. album.

Combining Carbon Accumulation and Hydroclimatic Variations Throughout the Holocene: Can we Detect a Climate Signal from Northeastern Canadian Boreal Peatlands ?

NASA Astrophysics Data System (ADS)

Garneau, M.; van Bellen, S.; Magnan, G.; Lamarre, A.; Thibault, A.

2013-12-01

In northeastern Canada, data on peatland development, carbon accumulation and hydroclimatic variations show changes throughout the Holocene period. Regional comparisons following south-north gradients from both western and eastern parts of the Québec province are used to evaluate the long-term processes influencing the peatlands carbon dynamics in this region of Canada. Seven different ecoclimatic subregions of the boreal biome distributed along two main geographic gradients (continental and maritime) have been characterized in terms of carbon accumulation and hydroclimatic variations. Results show an important maritime influence in terms of temperature (in particular through sea ice cover duration), relative humidity and wind exposure on peatland dynamics. In all regions, except in depressed areas, forests have first colonized the land following ice retreat and withdrawal of the marine waters. Peat accumulation has been initiated by paludification from 5500 cal BP mainly. Results show variations in the timing of trophic status transitions but there is a relative synchronic decrease in peat C accumulation in all regions from the Neoglacial cooling period. Cooler climatic conditions seem responsible for a decrease in biomass productivity and a rise in bog surface wetness due to lower evapotranspiration. Changes in hydroclimatic conditions may also have favored the development or expansion of pools and flarks at the peatland surfaces. These allogenic conditions also mediated by internal (autogenic) processes have been important factors controlling the long-term carbon dynamics of the studied peatlands. Impacts on carbon dioxide uptake and methane emissions through time require further considerations to evaluate the response of these systems to climate change.

Natural positive selection and north-south genetic diversity in East Asia.

PubMed

Suo, Chen; Xu, Haiyan; Khor, Chiea-Chuen; Ong, Rick Th; Sim, Xueling; Chen, Jieming; Tay, Wan-Ting; Sim, Kar-Seng; Zeng, Yi-Xin; Zhang, Xuejun; Liu, Jianjun; Tai, E-Shyong; Wong, Tien-Yin; Chia, Kee-Seng; Teo, Yik-Ying

2012-01-01

Recent reports have identified a north-south cline in genetic variation in East and South-East Asia, but these studies have not formally explored the basis of these clinical differences. Understanding the origins of these variations may provide valuable insights in tracking down the functional variants in genomic regions identified by genetic association studies. Here we investigate the genetic basis of these differences with genome-wide data from the HapMap, the Human Genome Diversity Project and the Singapore Genome Variation Project. We implemented four bioinformatic measures to discover genomic regions that are considerably differentiated either between two Han Chinese populations in the north and south of China, or across 22 populations in East and South-East Asia. These measures prioritized genomic stretches with: (i) regional differences in the allelic spectrum for SNPs common to the two Han Chinese populations; (ii) differential evidence of positive selection between the two populations as quantified by integrated haplotype score (iHS) and cross-population extended haplotype homozygosity (XP-EHH); (iii) significant correlation between allele frequencies and geographical latitudes of the 22 populations. We also explored the extent of linkage disequilibrium variations in these regions, which is important in combining genetic association studies from North and South Chinese. Two of the regions that emerged are found in HLA class I and II, suggesting that the HLA imputation panel from the HapMap may not be directly applicable to every Chinese sample. This has important implications to autoimmune studies that plan to impute the classical HLA alleles to fine map the SNP association signals.

Natural positive selection and north–south genetic diversity in East Asia

PubMed Central

Suo, Chen; Xu, Haiyan; Khor, Chiea-Chuen; Ong, Rick TH; Sim, Xueling; Chen, Jieming; Tay, Wan-Ting; Sim, Kar-Seng; Zeng, Yi-Xin; Zhang, Xuejun; Liu, Jianjun; Tai, E-Shyong; Wong, Tien-Yin; Chia, Kee-Seng; Teo, Yik-Ying

2012-01-01

Recent reports have identified a north–south cline in genetic variation in East and South-East Asia, but these studies have not formally explored the basis of these clinical differences. Understanding the origins of these variations may provide valuable insights in tracking down the functional variants in genomic regions identified by genetic association studies. Here we investigate the genetic basis of these differences with genome-wide data from the HapMap, the Human Genome Diversity Project and the Singapore Genome Variation Project. We implemented four bioinformatic measures to discover genomic regions that are considerably differentiated either between two Han Chinese populations in the north and south of China, or across 22 populations in East and South-East Asia. These measures prioritized genomic stretches with: (i) regional differences in the allelic spectrum for SNPs common to the two Han Chinese populations; (ii) differential evidence of positive selection between the two populations as quantified by integrated haplotype score (iHS) and cross-population extended haplotype homozygosity (XP-EHH); (iii) significant correlation between allele frequencies and geographical latitudes of the 22 populations. We also explored the extent of linkage disequilibrium variations in these regions, which is important in combining genetic association studies from North and South Chinese. Two of the regions that emerged are found in HLA class I and II, suggesting that the HLA imputation panel from the HapMap may not be directly applicable to every Chinese sample. This has important implications to autoimmune studies that plan to impute the classical HLA alleles to fine map the SNP association signals. PMID:21792231

Digenic inheritance in autosomal recessive non-syndromic hearing loss cases carrying GJB2 heterozygote mutations: assessment of GJB4, GJA1, and GJC3.

PubMed

Kooshavar, Daniz; Tabatabaiefar, Mohammad Amin; Farrokhi, Effat; Abolhasani, Marziye; Noori-Daloii, Mohammad-Reza; Hashemzadeh-Chaleshtori, Morteza

2013-02-01

Autosomal recessive non-syndromic hearing loss (ARNSHL) can be caused by many genes. However, mutations in the GJB2 gene, which encodes the gap-junction (GJ) protein connexin (Cx) 26, constitute a considerable proportion differing among population. Between 10 and 42 percent of patients with recessive GJB2 mutations carry only one mutant allele. Mutations in GJB4, GJA1, and GJC3 encoding Cx30.3, Cx43, and Cx29, respectively, can lead to HL. Combination of different connexins in heteromeric and heterotypic GJ assemblies is possible. This study aims to determine whether variations in any of the genes GJB4, GJA1 or GJC3 can be the second mutant allele causing the disease in the digenic mode of inheritance in the studied GJB2 heterozygous cases. We examined 34 unrelated GJB2 heterozygous ARNSHL subjects from different geographic and ethnic areas in Iran, using polymerase chain reaction (PCR) followed by direct DNA sequencing to identify any sequence variations in these genes. Restriction fragment length polymorphism (RFLP) assays were performed on 400 normal hearing individuals. Sequence analysis of GJB4 showed five heterozygous variations including c.451C>A, c.219C>T, c.507C>G, c.155_158delTCTG and c.542C>T, with only the latter variation not being detected in any of control samples. There were three heterozygous variations including c.758C>T, c.717G>A and c.3*dupA in GJA1 in four cases. We found no variations in GJC3 gene sequence. Our data suggest that GJB4 c.542C>T variant and less likely some variations of GJB4 and GJA1, but not possibly GJC3, can be assigned to ARNSHL in GJB2 heterozygous mutation carriers providing clues of the digenic pattern. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Linking stream ecology with morphological variability in a native freshwater fish from semi-arid Australia

PubMed Central

Lostrom, Samantha; Evans, Jonathan P; Grierson, Pauline F; Collin, Shaun P; Davies, Peter M; Kelley, Jennifer L

2015-01-01

Environmental variation is a potent force affecting phenotypic expression. While freshwater fishes have provided a compelling example of the link between the environment and phenotypic diversity, few studies have been conducted with arid-zone fishes, particularly those that occur in geographically isolated regions where species typically inhabit intermittent and ephemeral creeks. We investigated morphological variation of a freshwater fish (the western rainbowfish, Melanotaenia australis) inhabiting creeks in the Pilbara region of northwest Australia to determine whether body shape variation correlated with local environmental characteristics, including water velocity, habitat complexity, predator presence, and food availability. We expected that the geographic isolation of creeks within this arid region would result in habitat-specific morphological specializations. We used landmark-based geometric morphometrics to quantify the level of morphological variability in fish captured from 14 locations within three distinct subcatchments of a major river system. Western rainbowfish exhibited a range of morphologies, with variation in body depth accounting for a significant proportion (>42%) of the total variance in shape. Sexual dimorphism was also apparent, with males displaying deeper bodies than females. While the measured local habitat characteristics explained little of the observed morphological variation, fish displayed significant morphological differentiation at the level of the subcatchment. Local adaptation may partly explain the geographic patterns of body shape variation, but fine-scale genetic studies are required to disentangle the effects of genetic differentiation from environmentally determined phenotypic plasticity in body shape. Developing a better understanding of environment–phenotype relationships in species from arid regions will provide important insights into ecological and evolutionary processes in these unique and understudied habitats. PMID:26380663

Genetic Differentiation among Maruca vitrata F. (Lepidoptera: Crambidae) Populations on Cultivated Cowpea and Wild Host Plants: Implications for Insect Resistance Management and Biological Control Strategies

PubMed Central

Agunbiade, Tolulope A.; Coates, Brad S.; Datinon, Benjamin; Djouaka, Rousseau; Sun, Weilin; Tamò, Manuele; Pittendrigh, Barry R.

2014-01-01

Maruca vitrata Fabricius (Lepidoptera: Crambidae) is a polyphagous insect pest that feeds on a variety of leguminous plants in the tropics and subtropics. The contribution of host-associated genetic variation on population structure was investigated using analysis of mitochondrial cytochrome oxidase 1 (cox1) sequence and microsatellite marker data from M. vitrata collected from cultivated cowpea (Vigna unguiculata L. Walp.), and alternative host plants Pueraria phaseoloides (Roxb.) Benth. var. javanica (Benth.) Baker, Loncocarpus sericeus (Poir), and Tephrosia candida (Roxb.). Analyses of microsatellite data revealed a significant global FST estimate of 0.05 (P≤0.001). The program STRUCTURE estimated 2 genotypic clusters (co-ancestries) on the four host plants across 3 geographic locations, but little geographic variation was predicted among genotypes from different geographic locations using analysis of molecular variance (AMOVA; among group variation −0.68%) or F-statistics (F ST Loc = −0.01; P = 0.62). These results were corroborated by mitochondrial haplotype data (φSTLoc = 0.05; P = 0.92). In contrast, genotypes obtained from different host plants showed low but significant levels of genetic variation (F ST Host = 0.04; P = 0.01), which accounted for 4.08% of the total genetic variation, but was not congruent with mitochondrial haplotype analyses (φSTHost = 0.06; P = 0.27). Variation among host plants at a location and host plants among locations showed no consistent evidence for M. vitrata population subdivision. These results suggest that host plants do not significantly influence the genetic structure of M. vitrata, and this has implications for biocontrol agent releases as well as insecticide resistance management (IRM) for M. vitrata in West Africa. PMID:24647356

Spatiotemporal Variation in Avian Migration Phenology: Citizen Science Reveals Effects of Climate Change

PubMed Central

Hurlbert, Allen H.; Liang, Zhongfei

2012-01-01

A growing number of studies have documented shifts in avian migratory phenology in response to climate change, and yet there is a large amount of unexplained variation in the magnitude of those responses across species and geographic regions. We use a database of citizen science bird observations to explore spatiotemporal variation in mean arrival dates across an unprecedented geographic extent for 18 common species in North America over the past decade, relating arrival dates to mean minimum spring temperature. Across all species and geographic locations, species shifted arrival dates 0.8 days earlier for every °C of warming of spring temperature, but it was common for some species in some locations to shift as much as 3–6 days earlier per °C. Species that advanced arrival dates the earliest in response to warming were those that migrate more slowly, short distance migrants, and species with broader climatic niches. These three variables explained 63% of the interspecific variation in phenological response. We also identify a latitudinal gradient in the average strength of phenological response, with species shifting arrival earlier at southern latitudes than northern latitudes for the same degree of warming. This observation is consistent with the idea that species must be more phenologically sensitive in less seasonal environments to maintain the same degree of precision in phenological timing. PMID:22384050

Geographic variation in work injuries: a multilevel analysis of individual-level data and area-level factors within Canada.

PubMed

Morassaei, Sara; Breslin, F Curtis; Ibrahim, Selahadin A; Smith, Peter M; Mustard, Cameron A; Amick, Benjamin C; Shankardass, Ketan; Petch, Jeremy

2013-05-01

This study sought to examine provincial variation in work injuries and to assess whether contextual factors are associated with geographic variation in work injuries. Individual-level data from the 2003 and 2005 Canadian Community Health Survey was obtained for a representative sample of 89,541 Canadians aged 15 to 75 years old who reported working in the past 12 months. A multilevel regression model was conducted to identify geographic variation and contextual factors associated with the likelihood of reporting an activity limiting work injury [corrected], while adjusting for demographic and work variables. Provincial differences in work injuries were observed, even after controlling for other risk factors. Workers in western provinces such as Saskatchewan (adjusted odds ratio [AOR], 1.30; 95% confidence interval [CI], 1.09-1.55), Alberta (AOR, 1.31; 95% CI, 1.13-1.51), and British Columbia (AOR, 1.46; 95% CI, 1.26-1.71) had a higher risk of work injuries compared with Ontario workers. Indicators of area-level material and social deprivation were not associated with work injury risk. Provincial differences in work injuries suggest that broader factors acting as determinants of work injuries are operating across workplaces at a provincial level. Future research needs to identify the provincial determinants and whether similar large area-level factors are driving work injuries in other countries. Copyright © 2013 Elsevier Inc. All rights reserved.

Environmental metabolomics reveal geographic variation in aerobic metabolism and metabolic substrates in Mongolian gerbils (Meriones unguiculatus).

PubMed

Shi, Yao-Long; Chi, Qing-Sheng; Liu, Wei; Fu, He-Ping; Wang, De-Hua

2015-06-01

Mongolian gerbils (Meriones unguiculatus) have a large-scale distribution in northern China. Geographic physiological variations which related to energy and water metabolism are critical to animals' local adaptation and distribution. However, the underlying biochemical mechanism of such variation and its role in adaptation remains largely unknown. We used GC-MS metabolomics approach to investigate the biochemical adaptation of Mongolian gerbils from xeric (desert), transition (desert steppe) and mesic (typical steppe) environments. Gerbils in desert population had lower resting metabolic rate (RMR) and total evaporative water loss (TEWL) than mesic population. Serum metabolomics revealed that concentrations of five tricarboxylic acid cycle intermediates (citrate, cis-aconitate, α-ketoglutarate, fumarate and malate) were lower in desert population than mesic population. Gastrocnemius metabolomics and citrate synthase activity analysis showed a lower concentration of citrate and lower citrate synthase activity in desert population. These findings suggest that desert dwelling gerbils decrease RMR and TEWL via down-regulation of aerobic respiration. Gastrocnemius metabolomics also revealed that there were higher concentrations of glucose and glycolytic intermediates, but lower concentrations of lipids, amino acids and urea in desert population than mesic population. This geographic variation in metabolic substrates may enhance metabolic water production per oxygen molecule for desert population while constraining aerobic respiration to reduce RMR and TEWL. Copyright © 2015 Elsevier Inc. All rights reserved.

Population genetic structure and its implications for adaptive variation in memory and the hippocampus on a continental scale in food-caching black-capped chickadees.

PubMed

Pravosudov, V V; Roth, T C; Forister, M L; Ladage, L D; Burg, T M; Braun, M J; Davidson, B S

2012-09-01

Food-caching birds rely on stored food to survive the winter, and spatial memory has been shown to be critical in successful cache recovery. Both spatial memory and the hippocampus, an area of the brain involved in spatial memory, exhibit significant geographic variation linked to climate-based environmental harshness and the potential reliance on food caches for survival. Such geographic variation has been suggested to have a heritable basis associated with differential selection. Here, we ask whether population genetic differentiation and potential isolation among multiple populations of food-caching black-capped chickadees is associated with differences in memory and hippocampal morphology by exploring population genetic structure within and among groups of populations that are divergent to different degrees in hippocampal morphology. Using mitochondrial DNA and 583 AFLP loci, we found that population divergence in hippocampal morphology is not significantly associated with neutral genetic divergence or geographic distance, but instead is significantly associated with differences in winter climate. These results are consistent with variation in a history of natural selection on memory and hippocampal morphology that creates and maintains differences in these traits regardless of population genetic structure and likely associated gene flow. Published 2012. This article is a US Government work and is in the public domain in the USA.

Geographic Differences in Persistent Organic Pollutant Levels of Yellowfin Tuna.

PubMed

Nicklisch, Sascha C T; Bonito, Lindsay T; Sandin, Stuart; Hamdoun, Amro

2017-06-26

Fish are a source of persistent organic pollutants (POPs) in the human diet. Although species, trophic level, and means of production are typically considered in predicting fish pollutant load, and thus recommendations of consumption, capture location is usually not accounted for. Yellowfin tuna ( Thunnus albacares ) are harvested from across the world's oceans and are widely consumed. Here, we determined geographic variation in the overall mass, concentration, and composition of POPs in yellowfin and examined the differences in levels of several POP congeners of potential relevance to human health. We sampled dorsal muscle of 117 yellowfin tuna from 12 locations worldwide, and measured POP levels using combined liquid or gas chromatography and mass spectrometry according to U.S. Environmental Protection Agency standard procedures. POP levels varied significantly among sites, more than 36-fold on a mass basis. Individual fish levels ranged from 0.16 to 138.29 ng/g wet weight and lipid-normalized concentrations from 0.1 to 12.7 μM. Levels of 10 congeners that interfere with the cellular defense protein P-glycoprotein, termed transporter interfering compounds (TICs), ranged from 0.05 to 35.03 ng/g wet weight and from 0.03 to 3.32 μM in tuna lipid. Levels of TICs, and their individual congeners, were strongly associated with the overall POP load. Risk-based analysis of several carcinogenic POPs indicated that the fish with the highest levels of these potentially harmful compounds were clustered at specific geographic locations. Capture location is an important consideration when assessing the level and risk of human exposure to POPs through ingestion of wild fish. https://doi.org/10.1289/EHP518.

Geographic Differences in Persistent Organic Pollutant Levels of Yellowfin Tuna

PubMed Central

Nicklisch, Sascha C.T.; Bonito, Lindsay T.; Sandin, Stuart

2017-01-01

Background: Fish are a source of persistent organic pollutants (POPs) in the human diet. Although species, trophic level, and means of production are typically considered in predicting fish pollutant load, and thus recommendations of consumption, capture location is usually not accounted for. Objectives: Yellowfin tuna (Thunnus albacares) are harvested from across the world’s oceans and are widely consumed. Here, we determined geographic variation in the overall mass, concentration, and composition of POPs in yellowfin and examined the differences in levels of several POP congeners of potential relevance to human health. Methods: We sampled dorsal muscle of 117 yellowfin tuna from 12 locations worldwide, and measured POP levels using combined liquid or gas chromatography and mass spectrometry according to U.S. Environmental Protection Agency standard procedures. Results: POP levels varied significantly among sites, more than 36-fold on a mass basis. Individual fish levels ranged from 0.16 to 138.29ng/g wet weight and lipid-normalized concentrations from 0.1 to 12.7μM. Levels of 10 congeners that interfere with the cellular defense protein P-glycoprotein, termed transporter interfering compounds (TICs), ranged from 0.05 to 35.03ng/g wet weight and from 0.03 to 3.32μM in tuna lipid. Levels of TICs, and their individual congeners, were strongly associated with the overall POP load. Risk-based analysis of several carcinogenic POPs indicated that the fish with the highest levels of these potentially harmful compounds were clustered at specific geographic locations. Conclusions: Capture location is an important consideration when assessing the level and risk of human exposure to POPs through ingestion of wild fish. https://doi.org/10.1289/EHP518 PMID:28686554

Geographic proximity to specialized pediatric neurosurgical care in the contiguous United States.

PubMed

Ahmed, Abdul-Kareem; Duhaime, Ann-Christine; Smith, Timothy R

2018-04-01

OBJECTIVE Absent from an analysis of supply is consideration of the geographic distribution of pediatric neurosurgeons. Several patient socioeconomic metrics are known to be associated with outcome in pediatric neurosurgical diseases, such as hydrocephalus. The purpose of this study was to determine current geographic proximity to pediatric neurosurgical care using professional society databases. This study also sought to establish how socioeconomic factors are related to distance to care, using federal government-collected data. METHODS A list of currently practicing American Board of Pediatric Neurological Surgery (ABPNS)-certified neurosurgeons was compiled (ABPNS group). A separate list of practicing members of the Joint Pediatric Section (JPS) of the American Association of Neurological Surgeons/Congress of Neurological Surgeons was prepared (JPS group). Current primary practice locations were collected from each professional society database for each ABPNS or JPS neurosurgeon and were charted using ArcGIS mapping software (ESRI, version 10.3) on a United States Census Bureau map. The straight distance from the centroid of each zip code tabulation area (ZCTA) to the nearest neurosurgeon was determined by group type of neurosurgeon (ABPNS vs ABPNS + JPS). ZCTA-level data on demographic and socioeconomic factors were acquired from the American Community Survey, including data in children and young adults (0-18 or 0-24 years old) and the general population. These data were compared by distance to care and by groups of neurosurgeons (Pearson's chi-square analysis; the threshold of significance was set at 0.05). RESULTS Three hundred fifty-five practicing neurosurgeons providing pediatric care were located, of whom 215 surgeons were certified by the ABPNS and 140 were JPS members only. The analysis showed that 1 pediatric neurosurgeon is in practice for every 289,799 persons up to the age of 24 years. The average distance between a ZCTA and the nearest pediatric neurosurgeon is 63.3 miles (SE 0.3, range 0.0-499.7 miles). Geographic analysis showed that 27.1% of children live farther than 60 miles from an ABPNS-certified neurosurgeon and 19.7% from either an ABPNS-certified neurosurgeon or a JPS member. ZCTAs with children who live farther than 60 miles from a neurosurgeon providing pediatric care had a marginally higher rate of uninsured children, a higher percentage of families with children living below the federal poverty level, and a higher proportion of persons living in rural areas compared with ZCTAs with children who live within 60 miles of care (p < 0.005 for each finding). CONCLUSIONS The results of this study indicate that there is considerable variation in proximity to pediatric neurosurgical subspecialty care by geographic region. In addition, there is a relationship between distance to neurosurgical care and socioeconomic indicators. Optimization of access to pediatric neurosurgical care may involve strategies to overcome long geographic distances, particularly in rural and underserved areas. Such areas may have disproportionately lower socioeconomic levels, which may further limit access to care and affect outcomes. Both the total number of pediatric neurosurgeons per pediatric population and their geographic distribution could be important in determining appropriate subspecialty supply factors (e.g., the number of accredited pediatric neurosurgical fellowship training programs), as well as being important drivers of neurosurgical patient outcomes.

Comments on Correlations of IQ with Skin Color and Geographic-Demographic Variables

ERIC Educational Resources Information Center

Jensen, Arthur R.

2006-01-01

A large number of national and geographic population samples were used to test the hypothesis that the variation in mean values of skin color in the diverse populations are consistently correlated with the mean measured or estimated IQs of the various groups, as are some other physical variables, known as an ecological correlation. Straightforward…

Geographic patterns of genetic variation and population structure in Pinus aristata, Rocky Mountain bristlecone pine

Treesearch

Anna W. Schoettle; Betsy A. Goodrich; Valerie Hipkins; Christopher Richards; Julie Kray

2012-01-01

Pinus aristata Engelm., Rocky Mountain bristlecone pine, has a narrow core geographic and elevational distribution, occurs in disjunct populations, and is threatened by rapid climate change, white pine blister rust, and bark beetles. Knowledge of genetic diversity and population structure will help guide gene conservation strategies for this species. Sixteen sites...

Polymorphism in Languria taedata LeConte, its occurrence in coastal Louisiana Spartina marshes, and clarification of some Motschulsky languriine types (Coleoptera: Erotylidae: Languriinae)

USDA-ARS?s Scientific Manuscript database

We clarify the diagnosis and geographic distribution of the widespread, variable eastern coastal species Languria taedata LeConte, 1854, in North America. After examining types and the range of variation and geographical distribution of the species, we propose synonymy of L. erythrocephalus Blatchle...

Examining the geographical heterogeneity associated with risk of mistimed and unwanted pregnancy in Ghana.

PubMed

Amoako Johnson, Fiifi; Madise, Nyovani J

2009-03-01

After a decade of fertility decline, Ghana's fertility and the level of unmet need for contraception stalled in mid-transition in the late 1990s. Although the literature acknowledges this, the geographical patterns in unmet need have not been adequately documented. Spatial analysis of unmet need can reveal differences in usage and provision of contraceptive commodities, thereby pointing to geographical areas where contraceptive programmes should be strengthened. This study examines the geographical variation of the risk of mistimed and unwanted pregnancies between rural communities and also between urban communities of the three ecological zones of Ghana. The study also investigates if geographical differences in the risks of mistimed and unwanted pregnancies changed during the period when unmet need stalled at the national level. A multilevel regression model was applied to pooled data from the 1998 and 2003 Ghana Demographic and Health Surveys to examine the determinants of the risk of unintended pregnancies, while controlling for clustering of outcomes within communities. The results show that between the two surveys, there was no significant change in the levels of risk of mistimed and unwanted pregnancy. However, geographical heterogeneity in the risk of mistimed and unwanted pregnancy was observed, after controlling for relevant predictors. This showed concentration of mistimed pregnancies in some rural communities relative to others, and variation in the risk of unwanted pregnancies between urban communities. The results give a clear indication that bridging the inequality gap in contraceptive use requires programmes that are area-specific.

Multi-station investigation of spread F over Europe during low to high solar activity

NASA Astrophysics Data System (ADS)

Paul, Krishnendu Sekhar; Haralambous, Haris; Oikonomou, Christina; Paul, Ashik; Belehaki, Anna; Ioanna, Tsagouri; Kouba, Daniel; Buresova, Dalia

2018-04-01

Spread F is an ionospheric phenomenon which has been reported and analyzed extensively over equatorial regions on the basis of the Rayleigh-Taylor (R-T) instability. It has also been investigated over midlatitude regions, mostly over the Southern Hemisphere with its generation attributed to the Perkins instability mechanism. Over midlatitudes it has also been correlated with geomagnetic storms through the excitation of travelling ionospheric disturbances (TIDs) and subsequent F region uplifts. The present study deals with the occurrence rate of nighttime spread F events and their diurnal, seasonal and solar cycle variation observed over three stations in the European longitude sector namely Nicosia (geographic Lat: 35.29 °N, Long: 33.38 °E geographic: geomagnetic Lat: 29.38 °N), Athens (geographic Lat: 37.98 °N, Long: 23.73 °E geographic: geomagnetic Lat: 34.61 °N) and Pruhonice (geographic Lat: 50.05 °N, Long: 14.41 °E geographic: geomagnetic Lat: 47.7 °N) during 2009, 2015 and 2016 encompassing periods of low, medium and high solar activity, respectively. The latitudinal and longitudinal variation of spread F occurrence was examined by considering different instability triggering mechanisms and precursors which past literature identified as critical to the generation of spread F events. The main findings of this investigation is an inverse solar cycle and annual temporal dependence of the spread F occurrence rate and a different dominant spread F type between low and high European midlatitudes.

Rangewide phylogeography and landscape genetics of the Western U.S. endemic frog Rana boylii (Ranidae): Implications for the conservation of frogs and rivers

USGS Publications Warehouse

Lind, A.J.; Spinks, P.Q.; Fellers, G.M.; Shaffer, H.B.

2011-01-01

Genetic data are increasingly being used in conservation planning for declining species. We sampled both the ecological and distributional limits of the foothill yellow-legged frog, Rana boylii to characterize mitochondrial DNA (mtDNA) variation in this declining, riverine amphibian. We evaluated 1525 base pairs (bp) of cytochrome b and ND2 fragments for 77 individuals from 34 localities using phylogenetic and population genetic analyses. We constructed gene trees using maximum likelihood and Bayesian inference, and quantified genetic variance (using AMOVA and partial Mantel tests) within and among hydrologic regions and river basins. Several moderately supported, geographically-cohesive mtDNA clades were recovered for R. boylii. While genetic variation was low among populations in the largest, most inclusive clade, samples from localities at the edges of the geographic range demonstrated substantial genetic divergence from each other and from more central populations. Hydrologic regions and river basins, which represent likely dispersal corridors for R. boylii, accounted for significant levels of genetic variation. These results suggest that both rivers and larger hydrologic and geographic regions should be used in conservation planning for R. boylii. ?? 2010 US Government.

Geographical variation in life expectancy at birth in England and Wales is largely explained by deprivation.

PubMed

Woods, Laura M; Rachet, Bernard; Riga, Michael; Stone, Noell; Shah, Anjali; Coleman, Michel P

2005-02-01

To describe the population mortality profile of England and Wales by deprivation and in each government office region (GOR) during 1998, and to quantify the influence of geography and deprivation in determining life expectancy. Construction of life tables describing age specific mortality rates and life expectancy at birth from death registrations and estimated population counts. Life tables were created for (a) quintiles of income deprivation based on the income domain score of the index of multiple deprivation 2000, (b) each GOR and Wales, and (c) every combination of deprivation and geography. England and Wales.PATIENTS/ PARTICIPANTS: Residents of England and Wales, 1998. Life expectancy at birth varies with deprivation quintile and is highest in the most affluent groups. The differences are mainly attributable to differences in mortality rates under 75 years of age. Regional life expectancies display a clear north-south gradient. Linear regression analysis shows that deprivation explains most of the geographical variation in life expectancy. Geographical patterns of life expectancy identified within these data for England and Wales in 1998 are mainly attributable to variations in deprivation status as defined by the IMD 2000 income domain score.

Geographical variation in the skeletal morphology of red jungle fowl.

PubMed

Endo, H; Tsunekawa, N; Sonoe, M; Sasaki, Tї; Ogawa, H; Amano, T; Nguyen, T S; Phimphachanhvongsod, V; Kudo, K; Yonezawa, T; Akishinonomiya, F

2017-08-01

1. The skulls and postcranial skeletons of the red jungle fowl (Gallus gallus) were compared osteometrically between the populations from North and South Vietnam, North and Central Laos and Southeast Bangladesh. The populations include the three subspecies of G. g. spadiceus, G. g. gallus and G. g. murghi and were sampled to reveal the geographical morphological variations among populations in G. gallus. 2. The morphometric characteristics of subspecies murghi could be clearly distinguished from those of the other subspecies using a canonical discriminant analysis. However, the size and shape of the skull of the gallus population from South Vietnam were not statistically different from that of the subspecies spadiceus from North Laos. The canonical discriminant scores also clearly indicated that there were morphological similarities in the skulls of the populations from North Laos and South Vietnam. 3. From the results, therefore, it is concluded that red jungle fowls do not exhibit high levels of osteometric variation between geographical localities at least within the Indochinese Peninsula. 4. This contrasts with previous studies which have described these subspecies as having various external morphological differences and have argued that zoogeographical barriers exist between the north and south areas of the Indochinese Peninsula.

Micro- and macro-geographic scale effect on the molecular imprint of selection and adaptation in Norway spruce.

PubMed

Scalfi, Marta; Mosca, Elena; Di Pierro, Erica Adele; Troggio, Michela; Vendramin, Giovanni Giuseppe; Sperisen, Christoph; La Porta, Nicola; Neale, David B

2014-01-01

Forest tree species of temperate and boreal regions have undergone a long history of demographic changes and evolutionary adaptations. The main objective of this study was to detect signals of selection in Norway spruce (Picea abies [L.] Karst), at different sampling-scales and to investigate, accounting for population structure, the effect of environment on species genetic diversity. A total of 384 single nucleotide polymorphisms (SNPs) representing 290 genes were genotyped at two geographic scales: across 12 populations distributed along two altitudinal-transects in the Alps (micro-geographic scale), and across 27 populations belonging to the range of Norway spruce in central and south-east Europe (macro-geographic scale). At the macrogeographic scale, principal component analysis combined with Bayesian clustering revealed three major clusters, corresponding to the main areas of southern spruce occurrence, i.e. the Alps, Carpathians, and Hercynia. The populations along the altitudinal transects were not differentiated. To assess the role of selection in structuring genetic variation, we applied a Bayesian and coalescent-based F(ST)-outlier method and tested for correlations between allele frequencies and climatic variables using regression analyses. At the macro-geographic scale, the F(ST)-outlier methods detected together 11 F(ST)-outliers. Six outliers were detected when the same analyses were carried out taking into account the genetic structure. Regression analyses with population structure correction resulted in the identification of two (micro-geographic scale) and 38 SNPs (macro-geographic scale) significantly correlated with temperature and/or precipitation. Six of these loci overlapped with F(ST)-outliers, among them two loci encoding an enzyme involved in riboflavin biosynthesis and a sucrose synthase. The results of this study indicate a strong relationship between genetic and environmental variation at both geographic scales. It also suggests that an integrative approach combining different outlier detection methods and population sampling at different geographic scales is useful to identify loci potentially involved in adaptation.

Micro- and Macro-Geographic Scale Effect on the Molecular Imprint of Selection and Adaptation in Norway Spruce

PubMed Central

Scalfi, Marta; Mosca, Elena; Di Pierro, Erica Adele; Troggio, Michela; Vendramin, Giovanni Giuseppe; Sperisen, Christoph; La Porta, Nicola; Neale, David B.

2014-01-01

Forest tree species of temperate and boreal regions have undergone a long history of demographic changes and evolutionary adaptations. The main objective of this study was to detect signals of selection in Norway spruce (Picea abies [L.] Karst), at different sampling-scales and to investigate, accounting for population structure, the effect of environment on species genetic diversity. A total of 384 single nucleotide polymorphisms (SNPs) representing 290 genes were genotyped at two geographic scales: across 12 populations distributed along two altitudinal-transects in the Alps (micro-geographic scale), and across 27 populations belonging to the range of Norway spruce in central and south-east Europe (macro-geographic scale). At the macrogeographic scale, principal component analysis combined with Bayesian clustering revealed three major clusters, corresponding to the main areas of southern spruce occurrence, i.e. the Alps, Carpathians, and Hercynia. The populations along the altitudinal transects were not differentiated. To assess the role of selection in structuring genetic variation, we applied a Bayesian and coalescent-based F ST-outlier method and tested for correlations between allele frequencies and climatic variables using regression analyses. At the macro-geographic scale, the F ST-outlier methods detected together 11 F ST-outliers. Six outliers were detected when the same analyses were carried out taking into account the genetic structure. Regression analyses with population structure correction resulted in the identification of two (micro-geographic scale) and 38 SNPs (macro-geographic scale) significantly correlated with temperature and/or precipitation. Six of these loci overlapped with F ST-outliers, among them two loci encoding an enzyme involved in riboflavin biosynthesis and a sucrose synthase. The results of this study indicate a strong relationship between genetic and environmental variation at both geographic scales. It also suggests that an integrative approach combining different outlier detection methods and population sampling at different geographic scales is useful to identify loci potentially involved in adaptation. PMID:25551624

Geographic isolation drives divergence of uncorrelated genetic and song variation in the Ruddy-capped Nightingale-Thrush (Catharus frantzii; Aves: Turdidae).

PubMed

Ortiz-Ramírez, Marco F; Andersen, Michael J; Zaldívar-Riverón, Alejandro; Ornelas, Juan Francisco; Navarro-Sigüenza, Adolfo G

2016-01-01

Montane barriers influence the evolutionary history of lineages by promoting isolation of populations. The effects of these historical processes are evident in patterns of differentiation among extant populations, which are often expressed as genetic and behavioral variation between populations. We investigated the effects of geographic barriers on the evolutionary history of a Mesoamerican bird by studying patterns of genetic and vocal variation in the Ruddy-capped Nightingale-Thrush (Turdidae: Catharus frantzii), a non-migratory oscine bird that inhabits montane forests from central Mexico to Panama. We reconstructed the phylogeographic history and estimated divergence times between populations using Bayesian and maximum likelihood methods. We found strong support for the existence of four mitochondrial lineages of C. frantzii corresponding to isolated mountain ranges: Sierra Madre Oriental; Sierra Madre del Sur; the highlands of Chiapas, Guatemala, and El Salvador; and the Talamanca Cordillera. Vocal features in C. frantzii were highly variable among the four observed clades, but vocal variation and genetic variation were uncorrelated. Song variation in C. frantzii suggests that sexual selection and cultural drift could be important factors driving song differentiation in C. frantzii. Copyright © 2015 Elsevier Inc. All rights reserved.

Selected vitamins and essential elements in meat from semi-domesticated reindeer (Rangifer tarandus tarandus L.) in mid- and northern Norway: geographical variations and effect of animal population density.

PubMed

Hassan, Ammar Ali; Sandanger, Torkjel M; Brustad, Magritt

2012-07-01

Meat samples (n = 100) were collected from semi-domesticated reindeer originating from 10 grazing districts in Norway. We aimed at studying concentrations, correlations, geographical variations and the effect of animal population density on vitamins A, B3, B7, B12 and E, and calcium, iron, zinc, selenium, chromium and cobalt. Mean concentrations of vitamins A, B3, B7; B12 and E were <5 µg, 6.6 mg, <0.5 µg, 4.7 µg and 0.5 mg/100 g wet weight, respectively. Concentrations of calcium, iron, zinc, selenium, chromium and cobalt were 4.7 mg, 2.8 mg, 6.4 mg, 19.4 µg, 1.7 µg and 0.5 µg/100 g wet weight, respectively. Vitamin E and selenium were the nutrients that exhibited the largest geographical variations (p < 0.05), although no geographical gradient was observed for any of the studied nutrients. Age had a significant effect on zinc and selenium concentrations. Iron was significantly positive correlated with calcium (r = 0.3416, p < 0.01) and vitamin B12 with zinc (r = 0.35, p < 0.05). Reindeer from districts with low animal population density had significantly higher selenium concentration than those from districts with medium and high population densities (p < 0.01). Reindeer meat contained higher vitamin B12, iron, zinc and selenium concentrations when compared to Norwegian beef, lamb, mutton, pork and chicken meat.

The importance of regional models in assessing canine cancer incidences in Switzerland

PubMed Central

Leyk, Stefan; Brunsdon, Christopher; Graf, Ramona; Pospischil, Andreas; Fabrikant, Sara Irina

2018-01-01

Fitting canine cancer incidences through a conventional regression model assumes constant statistical relationships across the study area in estimating the model coefficients. However, it is often more realistic to consider that these relationships may vary over space. Such a condition, known as spatial non-stationarity, implies that the model coefficients need to be estimated locally. In these kinds of local models, the geographic scale, or spatial extent, employed for coefficient estimation may also have a pervasive influence. This is because important variations in the local model coefficients across geographic scales may impact the understanding of local relationships. In this study, we fitted canine cancer incidences across Swiss municipal units through multiple regional models. We computed diagnostic summaries across the different regional models, and contrasted them with the diagnostics of the conventional regression model, using value-by-alpha maps and scalograms. The results of this comparative assessment enabled us to identify variations in the goodness-of-fit and coefficient estimates. We detected spatially non-stationary relationships, in particular, for the variables related to biological risk factors. These variations in the model coefficients were more important at small geographic scales, making a case for the need to model canine cancer incidences locally in contrast to more conventional global approaches. However, we contend that prior to undertaking local modeling efforts, a deeper understanding of the effects of geographic scale is needed to better characterize and identify local model relationships. PMID:29652921

The importance of regional models in assessing canine cancer incidences in Switzerland.

PubMed

Boo, Gianluca; Leyk, Stefan; Brunsdon, Christopher; Graf, Ramona; Pospischil, Andreas; Fabrikant, Sara Irina

2018-01-01

Fitting canine cancer incidences through a conventional regression model assumes constant statistical relationships across the study area in estimating the model coefficients. However, it is often more realistic to consider that these relationships may vary over space. Such a condition, known as spatial non-stationarity, implies that the model coefficients need to be estimated locally. In these kinds of local models, the geographic scale, or spatial extent, employed for coefficient estimation may also have a pervasive influence. This is because important variations in the local model coefficients across geographic scales may impact the understanding of local relationships. In this study, we fitted canine cancer incidences across Swiss municipal units through multiple regional models. We computed diagnostic summaries across the different regional models, and contrasted them with the diagnostics of the conventional regression model, using value-by-alpha maps and scalograms. The results of this comparative assessment enabled us to identify variations in the goodness-of-fit and coefficient estimates. We detected spatially non-stationary relationships, in particular, for the variables related to biological risk factors. These variations in the model coefficients were more important at small geographic scales, making a case for the need to model canine cancer incidences locally in contrast to more conventional global approaches. However, we contend that prior to undertaking local modeling efforts, a deeper understanding of the effects of geographic scale is needed to better characterize and identify local model relationships.

Selected Vitamins and Essential Elements in Meat from Semi-Domesticated Reindeer (Rangifer tarandus tarandus L.) in Mid- and Northern Norway: Geographical Variations and Effect of Animal Population Density

PubMed Central

Hassan, Ammar Ali; Sandanger, Torkjel M.; Brustad, Magritt

2012-01-01

Meat samples (n = 100) were collected from semi-domesticated reindeer originating from 10 grazing districts in Norway. We aimed at studying concentrations, correlations, geographical variations and the effect of animal population density on vitamins A, B3, B7, B12 and E, and calcium, iron, zinc, selenium, chromium and cobalt. Mean concentrations of vitamins A, B3, B7; B12 and E were <5 µg, 6.6 mg, <0.5 µg, 4.7 µg and 0.5 mg/100 g wet weight, respectively. Concentrations of calcium, iron, zinc, selenium, chromium and cobalt were 4.7 mg, 2.8 mg, 6.4 mg, 19.4 µg, 1.7 µg and 0.5 µg/100 g wet weight, respectively. Vitamin E and selenium were the nutrients that exhibited the largest geographical variations (p < 0.05), although no geographical gradient was observed for any of the studied nutrients. Age had a significant effect on zinc and selenium concentrations. Iron was significantly positive correlated with calcium (r = 0.3416, p < 0.01) and vitamin B12 with zinc (r = 0.35, p < 0.05). Reindeer from districts with low animal population density had significantly higher selenium concentration than those from districts with medium and high population densities (p < 0.01). Reindeer meat contained higher vitamin B12, iron, zinc and selenium concentrations when compared to Norwegian beef, lamb, mutton, pork and chicken meat. PMID:22852060

Delineating modern variation from extinct morphology in the fossil record using shells of the Eastern Box Turtle (Terrapene carolina)

PubMed Central

2018-01-01

Characterization of morphological variation in the shells of extant Eastern Box Turtles, Terrapene carolina, provides a baseline for comparison to fossil populations. It also provides an example of the difficulties inherent to recognizing intraspecific diversity in the fossil record. The degree to which variation in fossils of T. carolina can be accommodated by extant variation in the species has been disagreed upon for over eighty years. Using morphometric analyses of the carapace, I address the relationship between modern and fossil T. carolina in terms of sexual dimorphism, geographic and subspecific variation, and allometric variation. Modern T. carolina display weak male-biased sexual size dimorphism. Sexual shape dimorphism cannot be reliably detected in the fossil record. Rather than a four-part subspecific division, patterns of geographic variation are more consistent with clinal variation between various regions in the species distribution. Allometric patterns are qualitatively similar to those documented in other emydid turtles and explain a significant amount of shape variation. When allometric patterns are accounted for, Holocene specimens are not significantly different from modern specimens. In contrast, several geologically older specimens have significantly different carapace shape with no modern analogue. Those large, fossilized specimens represent extinct variation occupying novel portions of morphospace. This study highlights the need for additional documentation of modern osteological variation that can be used to test hypotheses of intraspecific evolution in the fossil record. PMID:29513709

Power Distribution System Planning with GIS Consideration

NASA Astrophysics Data System (ADS)

Wattanasophon, Sirichai; Eua-Arporn, Bundhit

This paper proposes a method for solving radial distribution system planning problems taking into account geographical information. The proposed method can automatically determine appropriate location and size of a substation, routing of feeders, and sizes of conductors while satisfying all constraints, i.e. technical constraints (voltage drop and thermal limit) and geographical constraints (obstacle, existing infrastructure, and high-cost passages). Sequential quadratic programming (SQP) and minimum path algorithm (MPA) are applied to solve the planning problem based on net price value (NPV) consideration. In addition this method integrates planner's experience and optimization process to achieve an appropriate practical solution. The proposed method has been tested with an actual distribution system, from which the results indicate that it can provide satisfactory plans.

Amount and distribution of isozyme variation in various conifer species

Treesearch

M. Thompson Conkle

1980-01-01

Estimation of the relative amount and the geographic distribution of genetically controlled variation is a central topic of tree resource management. Biochemical data from the analysis of forest tree enzyme variants provides a direct and precise measure of allele frequencies of tree genes.

Continuity and Variation in Chinese Patterns of Socialization.

ERIC Educational Resources Information Center

Ho, David Y. F.

1989-01-01

Reviews literature on Chinese patterns of socialization. Discusses methodological issues with respect to continuity versus change through time, and variation across geographical locations, systematically considering variables of gender, age, and social class. Concludes that departures from traditional pattern in different locations are evident,…

Dentition of moustached tamarins (Saguinus mystax mystax) from Padre Isla, Peru, part 1: quantitative variation.

PubMed

Tornow, Matthew A; Ford, Susan M; Garber, Paul A; de Sa Sauerbrunn, Edward

2006-07-01

Analyses of dental variation in geographically restricted, wild populations of primates are extremely rare; however, such data form the best source for models of likely degrees of variation within and between fossil species. Data from dental casts of a geographically restricted population of moustached tamarins (Saguinus mystax mystax) from Padre Isla, Peru, document high levels of dental variability, as measured by coefficients of variation, in a nonsexually dimorphic species, despite its isolation and small population size. Like other primates, moustached tamarins show lower variability in the dimensions of the first molars and increased variability in the dimensions of the final molars in the toothrow. Moustached tamarins from Padre Isla have a distinctive pattern of variability in the remaining teeth, including more stable tooth lengths in the anterior and posterior portions of the toothrow, and more stable tooth widths in the midregion of the toothrow. High variability in incisor width may be due to age effects of a distinctive diet and pattern of dental wear.

Geographic Variation in Diagnostic Ability and Quality of Care Metrics: A Case Study of Ankylosing Spondylitis and Low Back Pain

PubMed Central

Shafrin, Jason; Griffith, Jenny; Shim, Jin Joo; Huber, Caroline; Ganguli, Arijit; Aubry, Wade

2017-01-01

Studies examining geographic variation in care for low back pain often focus on process and outcome measures conditional on patient diagnosis but generally do not take into account a physician’s ability to diagnose the root cause of low back pain. In our case study, we used increased detection of ankylosing spondylitis—a relatively rare inflammatory back disease—as a proxy for diagnostic ability and measured the relationship between ankylosing spondylitis detection, potentially inappropriate low back pain care, and cost. Using 5 years of health insurance claims data, we found significant variation in ankylosing spondylitis detection across metropolitan statistical areas (MSAs), with 8.1% of the variation in detection explained by a region’s racial composition. Furthermore, low back pain patients in MSAs with higher ankylosing spondylitis detection had 7.9% lower use of corticosteroids, 9.0% lower use of opioids, and 8.2% lower pharmacy cost, compared with patients living in low-detection MSAs. PMID:28548005

Temporal and spatial variation of hematozoans in Scandinavian willow warblers.

PubMed

Bensch, Staffan; Akesson, Susanne

2003-04-01

We examined temporal and geographical distribution of Haemoproteus sp. and Plasmodium sp. parasites in Swedish willow warblers, Phylloscopus trochilus. Parasite lineages were detected with molecular methods in 556 birds from 41 sites distributed at distances up to 1,500 km. Two mitochondrial lineages of Haemoproteus sp. were detected, WW1 in 56 birds and WW2 in 75 birds, that differed by 5.2% sequence divergence. We discuss the reasons behind the observed pattern of variation and identify 3 possible causes: (1) variation in the geographic distribution of the vector species, (2) the degree of parasite sharing with other bird species coexisting with the willow warbler, and (3) timing of transmission. Our results support a fundamental and rarely tested assumption of the now classical Hamilton-Zuk hypothesis of sexual selection, namely, that these parasites vary in both time and space. Such fluctuations of parasites and the selection pressure they supposedly impose on the host population are likely to maintain variation in immune system genes in the host population.

Seasonal variations in body melanism and size of the wolf spider Pardosa astrigera (Araneae: Lycosidae).

PubMed

Yang, Jinjian; Wu, Qijia; Xiao, Rong; Zhao, Jupeng; Chen, Jian; Jiao, Xiaoguo

2018-04-01

Variations in species morphology and life-history traits strongly correlate with geographic and climatic characteristics. Most studies on morphological variations in animals focus on ectotherms distributed on a large geographic scale across latitudinal and/or altitudinal gradient. However, the morphological variations of spiders living in the same habitats across different seasons have not been reported. In this study, we used the wolf spider, Pardosa astrigera , as a model to determine seasonal differences in adult body size, melanism, fecundity, and egg diameter both in the overwintering and the first generation for 2010 and 2016. The results showed that in 2010, both females and males of the overwintering generation were significantly darker than the first generation. Moreover, the overwintering females were markedly larger and produced more and bigger eggs than the first generation in both 2010 and 2016. Considering the overwintering P. astrigera experiencing low temperature and/or desiccation stress, these results suggest that substantially darker and larger body of the overwintering generation is adaptive to adverse conditions.

Assessment of Geographic Information Systems and Data Confidentiality Guidelines in STD Programs.

PubMed

Bissette, Jennifer M; Stover, Jeffrey A; Newman, Lori M; Delcher, Philip Christopher; Bernstein, Kyle T; Matthews, Lindsey

2009-01-01

Advancements in technology, such as geographic information systems (GIS), expand sexually transmitted disease (STD) program capacity for data analysis and visualization, and introduce additional confidentiality considerations. We developed a survey to examine GIS use among STD programs and to better understand existing data confidentiality practices. A Web-based survey of eight to 22 questions, depending on program-specific GIS capacity, was e-mailed to all STD program directors through the National Coalition of STD Directors in November 2004. Survey responses were accepted until April 15, 2005. Eighty-five percent of the 65 currently funded STD programs responded to the survey. Of those, 58% used GIS and 54% used geocoding. STD programs that did not use GIS (42%) identified lack of training and insufficient staff as primary barriers. Mapping, spatial analyses, and targeting program interventions were the main reasons for geocoding data. Nineteen of the 25 programs that responded to questions related to statistical disclosure rules employed a numerator rule, and 56% of those used a variation of the "Rule of 5." Of the 28 programs that responded to questions pertaining to confidentiality guidelines, 82% addressed confidentiality of GIS data informally. Survey findings showed the increasing use of GIS and highlighted the struggles STD programs face in employing GIS and protecting confidentiality. Guidance related to data confidentiality and additional access to GIS software and training could assist programs in optimizing use of spatial data.

Identification of ecological thresholds from variations in phytoplankton communities among lakes: contribution to the definition of environmental standards.

PubMed

Roubeix, Vincent; Danis, Pierre-Alain; Feret, Thibaut; Baudoin, Jean-Marc

2016-04-01

In aquatic ecosystems, the identification of ecological thresholds may be useful for managers as it can help to diagnose ecosystem health and to identify key levers to enable the success of preservation and restoration measures. A recent statistical method, gradient forest, based on random forests, was used to detect thresholds of phytoplankton community change in lakes along different environmental gradients. It performs exploratory analyses of multivariate biological and environmental data to estimate the location and importance of community thresholds along gradients. The method was applied to a data set of 224 French lakes which were characterized by 29 environmental variables and the mean abundances of 196 phytoplankton species. Results showed the high importance of geographic variables for the prediction of species abundances at the scale of the study. A second analysis was performed on a subset of lakes defined by geographic thresholds and presenting a higher biological homogeneity. Community thresholds were identified for the most important physico-chemical variables including water transparency, total phosphorus, ammonia, nitrates, and dissolved organic carbon. Gradient forest appeared as a powerful method at a first exploratory step, to detect ecological thresholds at large spatial scale. The thresholds that were identified here must be reinforced by the separate analysis of other aquatic communities and may be used then to set protective environmental standards after consideration of natural variability among lakes.

Measuring performance in off-patent drug markets: a methodological framework and empirical evidence from twelve EU Member States.

PubMed

Kanavos, Panos

2014-11-01

This paper develops a methodological framework to help evaluate the performance of generic pharmaceutical policies post-patent expiry or after loss of exclusivity in non-tendering settings, comprising five indicators (generic availability, time delay to and speed of generic entry, number of generic competitors, price developments, and generic volume share evolution) and proposes a series of metrics to evaluate performance. The paper subsequently tests this framework across twelve EU Member States (MS) by using IMS data on 101 patent expired molecules over the 1998-2010 period. Results indicate that significant variation exists in generic market entry, price competition and generic penetration across the study countries. Size of a geographical market is not a predictor of generic market entry intensity or price decline. Regardless of geographic or product market size, many off patent molecules lack generic competitors two years after loss of exclusivity. The ranges in each of the five proposed indicators suggest, first, that there are numerous factors--including institutional ones--contributing to the success of generic entry, price decline and market penetration and, second, MS should seek a combination of supply and demand-side policies in order to maximise cost-savings from generics. Overall, there seems to be considerable potential for faster generic entry, uptake and greater generic competition, particularly for molecules at the lower end of the market. Copyright © 2014. Published by Elsevier Ireland Ltd.

Exploring spatial patterns and drivers of forest fires in Portugal (1980-2014).

PubMed

Nunes, A N; Lourenço, L; Meira, A C Castro

2016-12-15

Information on the spatial incidence of fire ignition density and burnt area, trends and drivers of wildfires is vitally important in providing support for environmental and civil protection policies, designing appropriate prevention measures and allocating firefighting resources. The key objectives of this study were to analyse the geographical incidence and temporal trends for wildfires, as well as the main drivers of fire ignition and burnt area in Portugal on a municipal level. The results show that fires are not distributed uniformly throughout Portuguese territory, both in terms of ignition density and burnt area. One spot in the north-western area is well defined, covering 10% of the municipalities where more than one third of the total fire ignitions are concentrated. In >80% of Portuguese municipalities, ignition density has registered a positive trend since the 1980s. With regard to burnt area, 60% of the municipalities had a nil annual trend, 35% showed a positive trend and 5%, located mainly in the central region, revealed negative trends. Geographically weighted regression proved more efficient in identifying the most relevant physical and anthropogenic drivers of municipal wildfires in comparison with simple linear regression models. Topography, density of population, land cover and livestock were found to be significant in both ignition density and burnt area, although considerable variations were observed in municipal explanatory power. Copyright © 2016 Elsevier B.V. All rights reserved.

Sequence variation and phylogenetic analysis of envelope glycoprotein of hepatitis G virus.

PubMed

Lim, M Y; Fry, K; Yun, A; Chong, S; Linnen, J; Fung, K; Kim, J P

1997-11-01

A transfusion-transmissible agent provisionally designated hepatitis G virus (HGV) was recently identified. In this study, we examined the variability of the HGV genome by analysing sequences in the putative envelope region from 72 isolates obtained from diverse geographical sources. The 1561 nucleotide sequence of the E1/E2/NS2a region of HGV was determined from 12 isolates, and compared with three published sequences. The most variability was observed in 400 nucleotides at the N terminus of E2. We next analysed this 400 nucleotide envelope variable region (EV) from an additional 60 HGV isolates. This sequence varied considerably among the 75 isolates, with overall identity ranging from 79.3% to 99.5% at the nucleotide level, and from 83.5% to 100% at the amino acid level. However, hypervariable regions were not identified. Phylogenetic analyses indicated that the 75 HGV isolates belong to a single genotype. A single-tier distribution of evolutionary distances was observed among the 15 E1/E2/NS2a sequences and the 75 EV sequences. In contrast, 11 isolates of HCV were analysed and showed a three-tiered distribution, representing genotypes, subtypes, and isolates. The 75 isolates of HGV fell into four clusters on the phylogenetic tree. Tight geographical clustering was observed among the HGV isolates from Japan and Korea.

Origin, genetic diversity, and population structure of Chinese domestic sheep.

PubMed

Chen, Shan-Yuan; Duan, Zi-Yuan; Sha, Tao; Xiangyu, Jinggong; Wu, Shi-Fang; Zhang, Ya-Ping

2006-07-19

To characterize the origin, genetic diversity, and phylogeographic structure of Chinese domestic sheep, we here analyzed a 531-bp fragment of mtDNA control region of 449 Chinese autochthonous sheep from 19 breeds/populations from 13 geographic regions, together with previously reported 44 sequences from Chinese indigenous sheep. Phylogenetic analysis showed that all three previously defined lineages A, B, and C were found in all sampled Chinese sheep populations, except for the absence of lineage C in four populations. Network profiles revealed that the lineages B and C displayed a star-like phylogeny with the founder haplotype in the centre, and that two star-like subclades with two founder haplotypes were identified in lineage A. The pattern of genetic variation in lineage A, together with the divergence time between the two central founder haplotypes suggested that two independent domestication events have occurred in sheep lineage A. Considerable mitochondrial diversity was observed in Chinese sheep. Weak structuring was observed either among Chinese indigenous sheep populations or between Asian and European sheep and this can be attributable to long-term strong gene flow induced by historical human movements. The high levels of intra-population diversity in Chinese sheep and the weak phylogeographic structuring indicated three geographically independent domestication events have occurred and the domestication place was not only confined to the Near East, but also occurred in other regions.

Relevant Spatial Scales of Chemical Variation in Aplysina aerophoba

PubMed Central

Sacristan-Soriano, Oriol; Banaigs, Bernard; Becerro, Mikel A.

2011-01-01

Understanding the scale at which natural products vary the most is critical because it sheds light on the type of factors that regulate their production. The sponge Aplysina aerophoba is a common Mediterranean sponge inhabiting shallow waters in the Mediterranean and its area of influence in Atlantic Ocean. This species contains large concentrations of brominated alkaloids (BAs) that play a number of ecological roles in nature. Our research investigates the ecological variation in BAs of A. aerophoba from a scale of hundred of meters to thousand kilometers. We used a nested design to sample sponges from two geographically distinct regions (Canary Islands and Mediterranean, over 2500 km), with two zones within each region (less than 50 km), two locations within each zone (less than 5 km), and two sites within each location (less than 500 m). We used high-performance liquid chromatography to quantify multiple BAs and a spectrophotometer to quantify chlorophyll a (Chl a). Our results show a striking degree of variation in both natural products and Chl a content. Significant variation in Chl a content occurred at the largest and smallest geographic scales. The variation patterns of BAs also occurred at the largest and smallest scales, but varied depending on which BA was analyzed. Concentrations of Chl a and isofistularin-3 were negatively correlated, suggesting that symbionts may impact the concentration of some of these compounds. Our results underline the complex control of the production of secondary metabolites, with factors acting at both small and large geographic scales affecting the production of multiple secondary metabolites. PMID:22363236

Inclusive Education and Social Inequality: An Update of the Question and Some Geographical Considerations

ERIC Educational Resources Information Center

Rambla, Xavier; Ferrer, Ferran; Tarabini, Aina; Verger, Antoni

2008-01-01

The aim of this article is to review the current state of inclusive education in the world and to suggest a few relevant considerations. The first section "Two parallel concerns" retraces the inescapable connections between the educational aspects of inclusive education and more general concerns regarding inequality. The second section "Inclusive…

Geographic distribution of physicians in Portugal.

PubMed

Isabel, Correia; Paula, Veiga

2010-08-01

The main goals of this paper are to (1) analyse the inequality in geographic distribution of physicians and its evolution, (2) estimate the determinants of physician density, and (3) assess the importance of competitive and agglomerative forces in location decisions. The analysis of the geographic distribution of physicians is based on the ratio of general practitioners (GPs) and specialists to 1,000 inhabitants. The inequality is measured using Gini indices, coefficients of variation, and physician-to-population ratios. The econometric models were estimated by ordinary least squares. The data used refer to 1996 and 2007. The impact of the growing number of physicians, and therefore potential increased competition, on geographic distribution during the period studied was small. Nonetheless, there is evidence of competitive forces acting on the dynamics of doctor localisation. Geographic disparities in physician density are still high, and appear to be due mainly to geographic income inequality.

Global analysis of saliva as a source of bacterial genes for insights into human population structure and migration studies.

PubMed

Henne, Karsten; Li, Jing; Stoneking, Mark; Kessler, Olga; Schilling, Hildegard; Sonanini, Anne; Conrads, Georg; Horz, Hans-Peter

2014-08-22

The genetic diversity of the human microbiome holds great potential for shedding light on the history of our ancestors. Helicobacter pylori is the most prominent example as its analysis allowed a fine-scale resolution of past migration patterns including some that could not be distinguished using human genetic markers. However studies of H. pylori require stomach biopsies, which severely limits the number of samples that can be analysed. By focussing on the house-keeping gene gdh (coding for the glucose-6-phosphate dehydrogenase), on the virulence gene gtf (coding for the glucosyltransferase) of mitis-streptococci and on the 16S-23S rRNA internal transcribed spacer (ITS) region of the Fusobacterium nucleatum/periodonticum-group we here tested the hypothesis that bacterial genes from human saliva have the potential for distinguishing human populations. Analysis of 10 individuals from each of seven geographic regions, encompassing Africa, Asia and Europe, revealed that the genes gdh and ITS exhibited the highest number of polymorphic sites (59% and 79%, respectively) and most OTUs (defined at 99% identity) were unique to a given country. In contrast, the gene gtf had the lowest number of polymorphic sites (21%), and most OTUs were shared among countries. Most of the variation in the gdh and ITS genes was explained by the high clonal diversity within individuals (around 80%) followed by inter-individual variation of around 20%, leaving the geographic region as providing virtually no source of sequence variation. Conversely, for gtf the variation within individuals accounted for 32%, between individuals for 57% and among geographic regions for 11%. This geographic signature persisted upon extension of the analysis to four additional locations from the American continent. Pearson correlation analysis, pairwise Fst-cluster analysis as well as UniFrac analyses consistently supported a tree structure in which the European countries clustered tightly together and branched with American countries and South Africa, to the exclusion of Asian countries and the Congo. This study shows that saliva harbours protein-coding bacterial genes that are geographically structured, and which could potentially be used for addressing previously unresolved human migration events.

Geographic variation and effect of area-level poverty rate on colorectal cancer screening.

PubMed

Lian, Min; Schootman, Mario; Yun, Shumei

2008-10-16

With a secular trend of increasing colorectal cancer (CRC) screening, concerns about disparities in CRC screening also have been rising. It is unclear if CRC screening varies geographically, if area-level poverty rate affects CRC screening, and if individual-level characteristics mediate the area-level effects on CRC screening. Using 2006 Missouri Behavioral Risk Factor Surveillance System (BRFSS) data, a multilevel study was conducted to examine geographic variation and the effect of area-level poverty rate on CRC screening use among persons age 50 or older. Individuals were nested within ZIP codes (ZIP5 areas), which in turn, were nested within aggregations of ZIP codes (ZIP3 areas). Six groups of individual-level covariates were considered as potential mediators. An estimated 51.8% of Missourians aged 50 or older adhered to CRC screening recommendations. Nearly 15% of the total variation in CRC screening lay between ZIP5 areas. Persons residing in ZIP5 areas with > or = 10% of poverty rate had lower odds of CRC screening use than those residing in ZIP5 areas with <10% poverty rate (unadjusted odds ratio [OR], 0.69; 95% confidence interval [95% CI], 0.58-0.81; adjusted OR, 0.81; 95% CI, 0.67-0.98). Persons who resided in ZIP3 areas with > or = 20% poverty rate also had lower odds of following CRC screening guidelines than those residing in ZIP3 areas with <20% poverty rate (unadjusted OR, 0.66; 95% CI, 0.52-0.83; adjusted OR, 0.64; 95% CI, 0.50-0.83). Obesity, history of depression/anxiety and access to care were associated with CRC screening, but did not mediate the effect of area-level poverty on CRC screening. Large geographic variation of CRC screening exists in Missouri. Area-level poverty rate, independent of individual-level characteristics, is a significant predictor of CRC screening, but it only explains a small portion of the geographic heterogeneity of CRC screening. Individual-level factors we examined do not mediate the effect of the area-level poverty rate on CRC screening. Future studies should identify other area- and individual-level characteristics associated with CRC screening in Missouri.

Evidence for a population bottleneck in an Apicomplexan parasite of caribou and reindeer, Besnoitia tarandi

USDA-ARS?s Scientific Manuscript database

The evolutionary history and epidemiology of parasites may be reflected in the extent and geographic distribution of their genetic variation. Among coccidian parasites, the population structure of only Toxoplasma gondii has been extensively examined. Intraspecific variation in other coccidia, for ...

Estimating cigarette tax avoidance and evasion: evidence from a national sample of littered packs.

PubMed

Barker, Dianne C; Wang, Shu; Merriman, David; Crosby, Andrew; Resnick, Elissa A; Chaloupka, Frank J

2016-10-01

A number of recent studies document the proportion of all cigarette packs that are 'contraband' using discarded packs to measure tax avoidance and evasion, which we call tax non-compliance. To date, academic studies using discarded packs focused on relatively small geographical areas such as a city or a neighbourhood. We visited 160 communities across 38 US states in 2012 and collected data from littered cigarette packs as part of the State and Community Tobacco Control (SCTC) Research Initiative and the Bridging the Gap Community Obesity Measures Project (BTG-COMP). Data collectors were trained in a previously tested littered pack data collection protocol. Field teams collected 2116 packs with cellophane across 132 communities. We estimate a national tax non-compliance rate of 18.5% with considerable variation across regions. Suburban areas had lower non-compliance than urban areas as well as areas with high and low median household income areas compared with middle income areas. We present the first academic national study of tax non-compliance using littered cigarette packs. We demonstrate the feasibility of meaningful large-scale data collection using this methodology and document considerable variation in tax non-compliance across areas, suggesting that both policy differences and geography may be important in control of illicit tobacco use. Given the geography of open borders among countries with varying tax rates, this simple methodology may be appropriate to estimate tax non-compliance in countries that use tax stamps or other pack markings, such as health warnings. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

What you should know about land-cover data

USGS Publications Warehouse

Gallant, Alisa L.

2009-01-01

Wildlife biologists are using land-characteristics data sets for a variety of applications. Many kinds of landscape variables have been characterized and the resultant data sets or maps are readily accessible. Often, too little consideration is given to the accuracy or traits of these data sets, most likely because biologists do not know how such data are compiled and rendered, or the potential pitfalls that can be encountered when applying these data. To increase understanding of the nature of land-characteristics data sets, I introduce aspects of source information and data-handling methodology that include the following: ambiguity of land characteristics; temporal considerations and the dynamic nature of the landscape; type of source data versus landscape features of interest; data resolution, scale, and geographic extent; data entry and positional problems; rare landscape features; and interpreter variation. I also include guidance for determining the quality of land-characteristics data sets through metadata or published documentation, visual clues, and independent information. The quality or suitability of the data sets for wildlife applications may be improved with thematic or spatial generalization, avoidance of transitional areas on maps, and merging of multiple data sources. Knowledge of the underlying challenges in compiling such data sets will help wildlife biologists to better assess the strengths and limitations and determine how best to use these data.

An eco-hydrologic model of malaria outbreaks

NASA Astrophysics Data System (ADS)

Montosi, E.; Manzoni, S.; Porporato, A.; Montanari, A.

2012-03-01

Malaria is a geographically widespread infectious disease that is well known to be affected by climate variability at both seasonal and interannual timescales. In an effort to identify climatic factors that impact malaria dynamics, there has been considerable research focused on the development of appropriate disease models for malaria transmission and their consideration alongside climatic datasets. These analyses have focused largely on variation in temperature and rainfall as direct climatic drivers of malaria dynamics. Here, we further these efforts by considering additionally the role that soil water content may play in driving malaria incidence. Specifically, we hypothesize that hydro-climatic variability should be an important factor in controlling the availability of mosquito habitats, thereby governing mosquito growth rates. To test this hypothesis, we reduce a nonlinear eco-hydrologic model to a simple linear model through a series of consecutive assumptions and apply this model to malaria incidence data from three South African provinces. Despite the assumptions made in the reduction of the model, we show that soil water content can account for a significant portion of malaria's case variability beyond its seasonal patterns, whereas neither temperature nor rainfall alone can do so. Future work should therefore consider soil water content as a simple and computable variable for incorporation into climate-driven disease models of malaria and other vector-borne infectious diseases.

Focus on People and the Science Will Follow: Motivating Forces for Professional Movement in Stem Cell Research.

PubMed

Jacob, K J; Longstaff, H; Scott, C T; Illes, J

2015-08-01

The migration of researchers across geographic borders, or "brain drain" as it is commonly called, remains an important issue for governments around the world as loss or gain of highly qualified personnel in research can have substantial social, economic and political consequences. In the present study we seek to examine the forces that drive international professional migration of stem cell (SC) researchers, for which variation of SC policy in different jurisdictions has previously been implicated as a driving force. Structured interviews were carried out with a purposive sample of SC researchers in the professoriate who had made international moves after postdoctoral work between the years 2001-2014, or were actively anticipating a future move. Participants were asked to rank motivators of international movement on a 5-point Likert scale and prompted to elaborate on their answers. The results suggest that career considerations, availability of research funding, and personal considerations are of high importance to the participants when considering an international move, while the permissiveness or restrictiveness SC research policy is of comparably lower importance. Participants also expressed that international movements are beneficial to scientific careers overall. The findings have important implications for policy and strategies to attract and retain members of the SC research community.

A review of the global relationship among freshwater fish, autotrophic activity, and regional climate

USGS Publications Warehouse

Deines, Andrew M.; Bunnell, David B.; Rogers, Mark W.; Beard, T. Douglas; Taylor, William W.

2015-01-01

The relationship between autotrophic activity and freshwater fish populations is an important consideration for ecologists describing trophic structure in aquatic communities, fisheries managers tasked with increasing sustainable fisheries development, and fish farmers seeking to maximize production. Previous studies of the empirical relationships of autotrophic activity and freshwater fish yield have found positive relationships but were limited by small sample sizes, small geographic scopes, and the inability to compare patterns among many types of measurement techniques. Individual studies and reviews have also lacked consistent consideration of regional climate factors which may inform relationships between fisheries and autotrophic activity. We compiled data from over 700 freshwater systems worldwide and used meta-analysis and linear models to develop a comprehensive global synthesis between multiple metrics of autotrophic activity, fisheries, and climate indicators. Our results demonstrate that multiple metrics of fish (i.e., catch per unit effort, yield, and production) increase with autotrophic activity across a variety of fisheries. At the global scale additional variation in this positive relationship can be ascribed to regional climate differences (i.e., temperature and precipitation) across systems. Our results provide a method and proof-of-concept for assessing inland fisheries production at the global scale, where current estimates are highly uncertain, and may therefore inform the continued sustainable use of global inland fishery resources.

Ethical considerations and potential threats to validity for three methods commonly used to collect geographic information in studies among people who use drugs.

PubMed

Rudolph, Abby E; Bazzi, Angela Robertson; Fish, Sue

2016-10-01

Analyses with geographic data can be used to identify "hot spots" and "health service deserts", examine associations between proximity to services and their use, and link contextual factors with individual-level data to better understand how environmental factors influence behaviors. Technological advancements in methods for collecting this information can improve the accuracy of contextually-relevant information; however, they have outpaced the development of ethical standards and guidance, particularly for research involving populations engaging in illicit/stigmatized behaviors. Thematic analysis identified ethical considerations for collecting geographic data using different methods and the extent to which these concerns could influence study compliance and data validity. In-depth interviews with 15 Baltimore residents (6 recruited via flyers and 9 via peer-referral) reporting recent drug use explored comfort with and ethics of three methods for collecting geographic information: (1) surveys collecting self-reported addresses/cross-streets, (2) surveys using web-based maps to find/confirm locations, and (3) geographical momentary assessments (GMA), which collect spatiotemporally referenced behavioral data. Survey methods for collecting geographic data (i.e., addresses/cross-streets and web-based maps) were generally acceptable; however, participants raised confidentiality concerns regarding exact addresses for illicit/stigmatized behaviors. Concerns specific to GMA included burden of carrying/safeguarding phones and responding to survey prompts, confidentiality, discomfort with being tracked, and noncompliance with study procedures. Overall, many felt that confidentiality concerns could influence the accuracy of location information collected for sensitive behaviors and study compliance. Concerns raised by participants could result in differential study participation and/or study compliance and questionable accuracy/validity of location data for sensitive behaviors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Geographic patterns of genetic variation, population structure and adaptive traits in Pinus aristata, Rocky Mountain bristlecone pine

Treesearch

Anna W. Schoettle; Betsy A. Goodrich; Valerie Hipkins; Christopher Richards; Julie Kray

2011-01-01

Pinus aristata Engelm., Rocky Mountain bristlecone pine, has a narrow geographic and elevational distribution and occurs in disjunct mountain-top populations throughout Colorado and New Mexico in its core range. The species' unique aesthetic and ecological traits combined with the threats of the exotic disease white pine blister rust (WPBR), climate change in high...

Intracultural variation of knowledge about wild plant uses in the Biosphere Reserve Grosses Walsertal (Austria)

PubMed Central

2012-01-01

Background Leading scholars in ethnobiology and ethnomedicine continuously stress the need for moving beyond the bare description of local knowledge and to additionally analyse and theorise about the characteristics and dynamics of human interactions with plants and related local knowledge. Analyses of the variation of local knowledge are thereby perceived as minimal standard. In this study we investigate the distribution and variation of wild plant knowledge in five domains: food, drinks, human medicine, veterinary medicine and customs. We assess relations between the wild plant knowledge of informants and their socio-demographic as well as geographic background. Method Research was conducted in the Biosphere Reserve Grosses Walsertal, Austria. Structured questionnaires were used to inquire wild plant knowledge from 433 informants with varying socio-demographic and geographic background. Children assisted in the data collection. Data was analysed using descriptive statistics and generalized linear models. Results and discussion A majority of respondents is familiar with wild plant uses, however to varying degrees. Knowledge variations depend on the socio-demographic and geographic background of the informants as well as on the domains of knowledge under investigation: women, older informants and homegardeners report more human medicinal applications and applications in drinks than men, younger informants and non-homegardeners; farmers know a greater variety of veterinary medicinal applications than non-farmers; the place of residence relates significantly to food and veterinary uses. Customs are difficult to investigate in standardized matrices. The household-related distribution of work and the general socio-cultural context are especially helpful in order to explain intracultural variation of knowledge in the Grosses Walsertal. Conclusions Research on the intracultural variation of local knowledge exposes cultural characteristics and highlights the cultural embeddedness of local knowledge. The impact of socio-cultural developments on local knowledge may be anticipated from understanding the intracultural variation of knowledge. PMID:22770375

Intraspecific karyotypic polymorphism is highly concordant with allozyme variation in Lysimachia mauritiana (Primulaceae: Myrsinoideae) in Taiwan: implications for the colonization history and dispersal patterns of coastal plants

PubMed Central

Kono, Yoshiko; Chung, Kuo-Fang; Chen, Chih-Hui; Hoshi, Yoshikazu; Setoguchi, Hiroaki; Chou, Chang-Hung; Oginuma, Kazuo; Peng, Ching-I

2012-01-01

Background and Aims Investigating intraspecific karyotypic and genetic variations jointly can provide unique insights into how historical, ecological and cytogenetic factors influence microevolution. A coastal herb, Lysimachia mauritiana, exhibits extensive karyotypic polymorphism and displays a complex cytogeographic pattern across the Ryukyus. To explore whether a similar degree of chromosomal variation exists south of the Ryukyus, and in an attempt to ascertain the mechanisms that may have generated the patterns, comprehensive sampling was conducted in Taiwan. Methods Karyotypes were analysed at mitotic metaphase for 550 individuals from 42 populations throughout Taiwan Proper and its adjacent islands. In addition, genetic variation was estimated using 12 allozymes (21 loci) of 314 individuals sampled from 12 localities. Key Results Four chromosome numbers and eight cytotypes, including four endemic cytotypes, were detected. Cytotype distributions were highly structured geographically, with single cytotypes present in most populations and four major cytotypes dominating the north, east and south of Taiwan and the Penghu Archipelago. Allozyme variation was very low and F-statistics indicated an extremely high level of population differentiation, implying limited gene flow among populations. Cluster analysis of allozyme variation uncovered four geographic groups, each corresponding perfectly to the four dominant cytotypes. The geographic structure of cytotype distribution and allozyme variation probably resulted from severe genetic drift triggered by genetic bottlenecks, suggesting that Taiwanese populations were likely to be derived from four independent founder events. In the few localities with multiple cytotypes, cytogeographic patterns and inferences of chromosomal evolution revealed a trend of northward dispersal, consistent with the course of the Kuroshio Current that has been influential in shaping the coastal biota of the region. Conclusions The data elucidate the patterns of colonization and the effects of the Kuroshio Current on the distribution of L. mauritiana in Taiwan. These inferences are highly relevant to other coastal plant species in the region and will stimulate further studies. PMID:23022678

Altitude and latitude variations in avionics SEU and atmospheric neutron flux

DOE Office of Scientific and Technical Information (OSTI.GOV)

Normand, E.; Baker, T.J.

1993-12-01

The direct cause of single event upsets in SRAMs at aircraft altitudes by the atmospheric neutrons has previously been documented. The variation of the in-flight SEU rate with latitude is demonstrated by new data over a wide range of geographical locations. New measurements and models of the atmospheric neutron flux are also evaluated to characterize its variation with altitude, latitude and solar activity.

Geographic remoteness, area-level socioeconomic disadvantage and inequalities in colorectal cancer survival in Queensland: a multilevel analysis

PubMed Central

2013-01-01

Background To explore the impact of geographical remoteness and area-level socioeconomic disadvantage on colorectal cancer (CRC) survival. Methods Multilevel logistic regression and Markov chain Monte Carlo simulations were used to analyze geographical variations in five-year all-cause and CRC-specific survival across 478 regions in Queensland Australia for 22,727 CRC cases aged 20–84 years diagnosed from 1997–2007. Results Area-level disadvantage and geographic remoteness were independently associated with CRC survival. After full multivariate adjustment (both levels), patients from remote (odds Ratio [OR]: 1.24, 95%CrI: 1.07-1.42) and more disadvantaged quintiles (OR = 1.12, 1.15, 1.20, 1.23 for Quintiles 4, 3, 2 and 1 respectively) had lower CRC-specific survival than major cities and least disadvantaged areas. Similar associations were found for all-cause survival. Area disadvantage accounted for a substantial amount of the all-cause variation between areas. Conclusions We have demonstrated that the area-level inequalities in survival of colorectal cancer patients cannot be explained by the measured individual-level characteristics of the patients or their cancer and remain after adjusting for cancer stage. Further research is urgently needed to clarify the factors that underlie the survival differences, including the importance of geographical differences in clinical management of CRC. PMID:24152961

Glacial reduction and millennial-scale variations in Drake Passage throughflow.

PubMed

Lamy, Frank; Arz, Helge W; Kilian, Rolf; Lange, Carina B; Lembke-Jene, Lester; Wengler, Marc; Kaiser, Jérôme; Baeza-Urrea, Oscar; Hall, Ian R; Harada, Naomi; Tiedemann, Ralf

2015-11-03

The Drake Passage (DP) is the major geographic constriction for the Antarctic Circumpolar Current (ACC) and exerts a strong control on the exchange of physical, chemical, and biological properties between the Atlantic, Pacific, and Indian Ocean basins. Resolving changes in the flow of circumpolar water masses through this gateway is, therefore, crucial for advancing our understanding of the Southern Ocean's role in global ocean and climate variability. Here, we reconstruct changes in DP throughflow dynamics over the past 65,000 y based on grain size and geochemical properties of sediment records from the southernmost continental margin of South America. Combined with published sediment records from the Scotia Sea, we argue for a considerable total reduction of DP transport and reveal an up to ∼ 40% decrease in flow speed along the northernmost ACC pathway entering the DP during glacial times. Superimposed on this long-term decrease are high-amplitude, millennial-scale variations, which parallel Southern Ocean and Antarctic temperature patterns. The glacial intervals of strong weakening of the ACC entering the DP imply an enhanced export of northern ACC surface and intermediate waters into the South Pacific Gyre and reduced Pacific-Atlantic exchange through the DP ("cold water route"). We conclude that changes in DP throughflow play a critical role for the global meridional overturning circulation and interbasin exchange in the Southern Ocean, most likely regulated by variations in the westerly wind field and changes in Antarctic sea ice extent.

Genetic variation and phylogenetic relationship analysis of Jatropha curcas L. inferred from nrDNA ITS sequences.

PubMed

Guo, Guo-Ye; Chen, Fang; Shi, Xiao-Dong; Tian, Yin-Shuai; Yu, Mao-Qun; Han, Xue-Qin; Yuan, Li-Chun; Zhang, Ying

2016-01-01

Genetic variation and phylogenetic relationships among 102 Jatropha curcas accessions from Asia, Africa, and the Americas were assessed using the internal transcribed spacer region of nuclear ribosomal DNA (nrDNA ITS). The average G+C content (65.04%) was considerably higher than the A+T (34.96%) content. The estimated genetic diversity revealed moderate genetic variation. The pairwise genetic divergences (GD) between haplotypes were evaluated and ranged from 0.000 to 0.017, suggesting a higher level of genetic differentiation in Mexican accessions than those of other regions. Phylogenetic relationships and intraspecific divergence were inferred by Bayesian inference (BI), maximum parsimony (MP), and median joining (MJ) network analysis and were generally resolved. The J. curcas accessions were consistently divided into three lineages, groups A, B, and C, which demonstrated distant geographical isolation and genetic divergence between American accessions and those from other regions. The MJ network analysis confirmed that Central America was the possible center of origin. The putative migration route suggested that J. curcas was distributed from Mexico or Brazil, via Cape Verde and then split into two routes. One route was dispersed to Spain, then migrated to China, eventually spreading to southeastern Asia, while the other route was dispersed to Africa, via Madagascar and migrated to China, later spreading to southeastern Asia. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Glacial reduction and millennial-scale variations in Drake Passage throughflow

PubMed Central

Lamy, Frank; Arz, Helge W.; Kilian, Rolf; Lange, Carina B.; Lembke-Jene, Lester; Wengler, Marc; Kaiser, Jérôme; Baeza-Urrea, Oscar; Hall, Ian R.; Harada, Naomi; Tiedemann, Ralf

2015-01-01

The Drake Passage (DP) is the major geographic constriction for the Antarctic Circumpolar Current (ACC) and exerts a strong control on the exchange of physical, chemical, and biological properties between the Atlantic, Pacific, and Indian Ocean basins. Resolving changes in the flow of circumpolar water masses through this gateway is, therefore, crucial for advancing our understanding of the Southern Ocean’s role in global ocean and climate variability. Here, we reconstruct changes in DP throughflow dynamics over the past 65,000 y based on grain size and geochemical properties of sediment records from the southernmost continental margin of South America. Combined with published sediment records from the Scotia Sea, we argue for a considerable total reduction of DP transport and reveal an up to ∼40% decrease in flow speed along the northernmost ACC pathway entering the DP during glacial times. Superimposed on this long-term decrease are high-amplitude, millennial-scale variations, which parallel Southern Ocean and Antarctic temperature patterns. The glacial intervals of strong weakening of the ACC entering the DP imply an enhanced export of northern ACC surface and intermediate waters into the South Pacific Gyre and reduced Pacific–Atlantic exchange through the DP (“cold water route”). We conclude that changes in DP throughflow play a critical role for the global meridional overturning circulation and interbasin exchange in the Southern Ocean, most likely regulated by variations in the westerly wind field and changes in Antarctic sea ice extent. PMID:26417070

Evaluation of land use regression models for NO2 in El Paso, Texas, USA

PubMed Central

Gonzales, Melissa; Myers, Orrin; Smith, Luther; Olvera, Hector A.; Mukerjee, Shaibal; Li, Wen-Whai; Pingitore, Nicholas; Amaya, Maria; Burchiel, Scott; Berwick, Marianne

2012-01-01

Developing suitable exposure estimates for air pollution health studies is problematic due to spatial and temporal variation in concentrations and often limited monitoring data. Though land use regression models (LURs) are often used for this purpose, their applicability to later periods of time, larger geographic areas, and seasonal variation is largely untested. We evaluate a series of mixed model LURs to describe the spatial-temporal gradients of NO2 across El Paso County, Texas based on measurements collected during cool and warm seasons in 2006–2007 (2006–7). We also evaluated performance of a general additive model (GAM) developed for central El Paso in 1999 to assess spatial gradients across the County in 2006–7. Five LURs were developed iteratively from the study data and their predictions were averaged to provide robust nitrogen dioxide (NO2) concentration gradients across the county. Despite differences in sampling time frame, model covariates and model estimation methods, predicted NO2 concentration gradients were similar in the current study as compared to the 1999 study. Through a comprehensive LUR modeling campaign, it was shown that the nature of the most influential predictive variables remained the same for El Paso between the 1999 and 2006–7. The similar LUR results obtained here demonstrate that, at least for El Paso, LURs developed from prior years may still be applicable to assess exposure conditions in subsequent years and in different seasons when seasonal variation is taken into consideration. PMID:22728301

Global trends in the incidence and prevalence of type 2 diabetes in children and adolescents: a systematic review and evaluation of methodological approaches.

PubMed

Fazeli Farsani, S; van der Aa, M P; van der Vorst, M M J; Knibbe, C A J; de Boer, A

2013-07-01

This study aimed to systematically review what has been reported on the incidence and prevalence of type 2 diabetes in children and adolescents, to scrutinise the methodological issues observed in the included studies and to prepare recommendations for future research and surveillances. PubMed, the Cochrane Database of Systematic Reviews, Scopus, EMBASE and Web of Science were searched from inception to February 2013. Population-based studies on incidence and prevalence of type 2 diabetes in children and adolescents were summarised and methodologically evaluated. Owing to substantial methodological heterogeneity and considerable differences in study populations a quantitative meta-analysis was not performed. Among 145 potentially relevant studies, 37 population-based studies met the inclusion criteria. Variations in the incidence and prevalence rates of type 2 diabetes in children and adolescents were mainly related to age of the study population, calendar time, geographical regions and ethnicity, resulting in a range of 0-330 per 100,000 person-years for incidence rates, and 0-5,300 per 100,000 population for prevalence rates. Furthermore, a substantial variation in the methodological characteristics was observed for response rates (60-96%), ascertainment rates (53-99%), diagnostic tests and criteria used to diagnose type 2 diabetes. Worldwide incidence and prevalence of type 2 diabetes in children and adolescents vary substantially among countries, age categories and ethnic groups and this can be explained by variations in population characteristics and methodological dissimilarities between studies.

[Variations among Spanish regions in the use of three cardiovascular technologies].

PubMed

Fitch-Warner, Kathryn; García de Yébenes, María J; Lázaro y de Mercado, Pablo; Belaza-Santurde, Javier

2006-12-01

There is evidence that some geographic variations in the use of medical technologies are not explained by differences in disease burden. The objectives of this study were to quantify variability in the use of percutaneous coronary intervention (PCI), implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) in Spanish autonomous regions and to try to explain the variability found for the first two technologies. Linear regression models were developed in which the number of procedures performed per million population (pmp) in 2003 in each autonomous region was the dependent variable. Independent variables used included indices of technology provision, regional wealth, and disease burden. For PCI, the mean utilization rate for the whole of Spain was 1038 procedures pmp, with a high-low ratio of 1.95. Differences in gross domestic product explained 21% of the variability, but there was no relationship between the number of procedures performed and disease burden. For ICDs, the mean number of procedures performed in the whole of Spain was 46 pmp, with a high-low ratio of 3.04. As for PCI, differences in regional wealth explained 40% of the variability, with disease burden making no contribution. For CRT, the mean number of procedures performed in Spain in 2003 was 15 pmp, with a high-low ratio of 15.7. The considerable regional variation that exists in the use of these three medical technologies is principally explained by differences in regional wealth and not in disease burden.

Viable progeny from crosses between geographically isolated populations of Podisus (Hemiptera: Pentatomidae) indicate a single species

USDA-ARS?s Scientific Manuscript database

Discrepancies in reports on the presence of Podisus maculiventris (Say) (Hemiptera: Pentatomidae) in the western region of USA, and morphological variations of the species brought into question whether the species existed west of the Rocky Mountains. In this study, morphological variations in color ...

Mechanisms of Vowel Variation in African American English

ERIC Educational Resources Information Center

Holt, Yolanda Feimster

2018-01-01

Purpose: This research explored mechanisms of vowel variation in African American English by comparing 2 geographically distant groups of African American and White American English speakers for participation in the African American Shift and the Southern Vowel Shift. Method: Thirty-two male (African American: n = 16, White American controls: n =…

Global Characteristics of Childhood Acute Promyelocytic Leukemia

PubMed Central

Zhang, L; Samad, A; Pombo-de-Oliveira, MS; Scelo, G; Smith, MT; Feusner, J; Wiemels, JL; Metayer, C

2014-01-01

Acute promyelocytic leukemia (APL) comprises approximately 5–10% of childhood acute myeloid leukemia (AML) cases in the US. While variation in this percentage among other populations was noted previously, global patterns of childhood APL have not been thoroughly characterized. In this comprehensive review of childhood APL, we examined its geographic pattern and the potential contribution of environmental factors to observed variation. In 142 studies (spanning >60 countries) identified, variation was apparent—de novo APL represented from 2% (Switzerland) to >50% (Nicaragua) of childhood AML in different geographic regions. Because a limited number of previous studies addressed specific environmental exposures that potentially underlie childhood APL development, we gathered 28 childhood cases of therapy-related APL, which exemplified associations between prior exposures to chemotherapeutic drugs/radiation and APL diagnosis. Future population-based studies examining childhood APL patterns and the potential association with specific environmental exposures and other risk factors are needed. PMID:25445717