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Sample records for geographic distribution host

  1. Angiostrongylus spp. in the Americas: geographical and chronological distribution of definitive hosts versus disease reports.

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    Valente, Romina; Robles, Maria Del Rosario; Navone, Graciela T; Diaz, Julia I

    2018-03-01

    Angiostrongyliasis is an infection caused by nematode worms of the genus Angiostrongylus. The adult worms inhabit the pulmonary arteries, heart, bronchioles of the lung, or mesenteric arteries of the caecum of definitive host. Of a total of 23 species of Angiostrongylus cited worldwide, only nine were registered in the American Continent. Two species, A. cantonensis and A. costaricensis, are considered zoonoses when the larvae accidentally parasitise man. In the present study, geographical and chronological distribution of definitive hosts of Angiostrongylus in the Americas is analysed in order to observe their relationship with disease reports. Moreover, the role of different definitive hosts as sentinels and dispersers of infective stages is discussed. The study area includes the Americas. First records of Angiostrongylus spp. in definitive or accidental hosts were compiled from the literature. Data were included in tables and figures and were matched to geographic information systems (GIS). Most geographical records of Angiostrongylus spp. both for definitive and accidental hosts belong to tropical areas, mainly equatorial zone. In relation to those species of human health importance, as A. cantonensis and A. costaricensis, most disease cases indicate a coincidence between the finding of definitive host and disease record. However, in some geographic site there are gaps between report of definitive host and disease record. In many areas, human populations have invaded natural environments and their socioeconomic conditions do not allow adequate medical care. Consequently, many cases for angiostrongyliasis could have gone unreported or unrecognised throughout history and in the nowadays. Moreover, the population expansion and the climatic changes invite to make broader and more complete range of observation on the species that involve possible epidemiological risks. This paper integrates and shows the current distribution of Angiostrongylus species in America

  2. Angiostrongylus spp. in the Americas: geographical and chronological distribution of definitive hosts versus disease reports

    Science.gov (United States)

    Valente, Romina; Robles, Maria del Rosario; Navone, Graciela T; Diaz, Julia I

    2018-01-01

    BACKGROUND Angiostrongyliasis is an infection caused by nematode worms of the genus Angiostrongylus. The adult worms inhabit the pulmonary arteries, heart, bronchioles of the lung, or mesenteric arteries of the caecum of definitive host. Of a total of 23 species of Angiostrongylus cited worldwide, only nine were registered in the American Continent. Two species, A. cantonensis and A. costaricensis, are considered zoonoses when the larvae accidentally parasitise man. OBJECTIVES In the present study, geographical and chronological distribution of definitive hosts of Angiostrongylus in the Americas is analysed in order to observe their relationship with disease reports. Moreover, the role of different definitive hosts as sentinels and dispersers of infective stages is discussed. METHODS The study area includes the Americas. First records of Angiostrongylus spp. in definitive or accidental hosts were compiled from the literature. Data were included in tables and figures and were matched to geographic information systems (GIS). FINDINGS Most geographical records of Angiostrongylus spp. both for definitive and accidental hosts belong to tropical areas, mainly equatorial zone. In relation to those species of human health importance, as A. cantonensis and A. costaricensis, most disease cases indicate a coincidence between the finding of definitive host and disease record. However, in some geographic site there are gaps between report of definitive host and disease record. In many areas, human populations have invaded natural environments and their socioeconomic conditions do not allow adequate medical care. MAIN CONCLUSIONS Consequently, many cases for angiostrongyliasis could have gone unreported or unrecognised throughout history and in the nowadays. Moreover, the population expansion and the climatic changes invite to make broader and more complete range of observation on the species that involve possible epidemiological risks. This paper integrates and shows the

  3. Molecular insight into systematics, host associations, life cycles and geographic distribution of the nematode family Rhabdiasidae.

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    Tkach, Vasyl V; Kuzmin, Yuriy; Snyder, Scott D

    2014-04-01

    Rhabdiasidae Railliet, 1915 is a globally distributed group of up to 100 known species of nematodes parasitic in amphibians and reptiles. This work presents the results of a molecular phylogenetic analysis of 36 species of Rhabdiasidae from reptiles and amphibians from six continents. New DNA sequences encompassing partial 18S rDNA, ITS1, 5.8S rDNA, ITS2 and partial 28S rDNA regions of nuclear ribosomal DNA were obtained from 27 species and pre-existing sequences for nine species were incorporated. The broad taxonomic, host and geographical coverage of the specimens allowed us to address long-standing questions in rhabdiasid systematics, evolution, geographic distribution, and patterns of host association. Our analysis demonstrated that rhabdiasids parasitic in snakes are an independent genus sister to the rest of the Rhabdiasidae, a status supported by life cycle data. Based on the combined evidence of molecular phylogeny, morphology and life cycle characteristics, a new genus Serpentirhabdias gen. nov. with the type species Serpentirhabdias elaphe (Sharpilo, 1976) comb. nov. is established. The phylogeny supports the monophyly of Entomelas Travassos, 1930, Pneumonema Johnston, 1916 and the largest genus of the family, Rhabdias Stiles and Hassall, 1905. DNA sequence comparisons demonstrate the presence of more than one species in the previously monotypic Pneumonema from Australian scincid lizards. The distribution of some morphological characters in the genus Rhabdias shows little consistency within the phylogenetic tree topology, in particular the apical structures widely used in rhabdiasid systematics. Our data suggest that some of the characters, while valuable for species differentiation, are not appropriate for differentiation among higher taxa and are of limited phylogenetic utility. Rhabdias is the only genus with a cosmopolitan distribution, but some of the lineages within Rhabdias are distributed on a single continent or a group of adjacent

  4. Local host specialization, host-switching, and dispersal shape the regional distributions of avian haemosporidian parasites.

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    Ellis, Vincenzo A; Collins, Michael D; Medeiros, Matthew C I; Sari, Eloisa H R; Coffey, Elyse D; Dickerson, Rebecca C; Lugarini, Camile; Stratford, Jeffrey A; Henry, Donata R; Merrill, Loren; Matthews, Alix E; Hanson, Alison A; Roberts, Jackson R; Joyce, Michael; Kunkel, Melanie R; Ricklefs, Robert E

    2015-09-08

    The drivers of regional parasite distributions are poorly understood, especially in comparison with those of free-living species. For vector-transmitted parasites, in particular, distributions might be influenced by host-switching and by parasite dispersal with primary hosts and vectors. We surveyed haemosporidian blood parasites (Plasmodium and Haemoproteus) of small land birds in eastern North America to characterize a regional parasite community. Distributions of parasite populations generally reflected distributions of their hosts across the region. However, when the interdependence between hosts and parasites was controlled statistically, local host assemblages were related to regional climatic gradients, but parasite assemblages were not. Moreover, because parasite assemblage similarity does not decrease with distance when controlling for host assemblages and climate, parasites evidently disperse readily within the distributions of their hosts. The degree of specialization on hosts varied in some parasite lineages over short periods and small geographic distances independently of the diversity of available hosts and potentially competing parasite lineages. Nonrandom spatial turnover was apparent in parasite lineages infecting one host species that was well-sampled within a single year across its range, plausibly reflecting localized adaptations of hosts and parasites. Overall, populations of avian hosts generally determine the geographic distributions of haemosporidian parasites. However, parasites are not dispersal-limited within their host distributions, and they may switch hosts readily.

  5. Geographic distribution of methyltransferases of Helicobacter pylori: evidence of human host population isolation and migration

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    Vítor Jorge MB

    2009-09-01

    Full Text Available Abstract Background Helicobacter pylori colonizes the human stomach and is associated with gastritis, peptic ulcer, and gastric cancer. This ubiquitous association between H. pylori and humans is thought to be present since the origin of modern humans. The H. pylori genome encodes for an exceptional number of restriction and modifications (R-M systems. To evaluate if R-M systems are an adequate tool to determine the geographic distribution of H. pylori strains, we typed 221 strains from Africa, America, Asia, and Europe, and evaluated the expression of different 29 methyltransferases. Results Independence tests and logistic regression models revealed that ten R-M systems correlate with geographical localization. The distribution pattern of these methyltransferases may have been originated by co-divergence of regional H. pylori after its human host migrated out of Africa. The expression of specific methyltransferases in the H. pylori population may also reflect the genetic and cultural background of its human host. Methyltransferases common to all strains, M. HhaI and M. NaeI, are likely conserved in H. pylori, and may have been present in the bacteria genome since the human diaspora out of Africa. Conclusion This study indicates that some methyltransferases are useful geomarkers, which allow discrimination of bacterial populations, and that can be added to our tools to investigate human migrations.

  6. Temporal, geographic, and host distribution of avian paramyxovirus 1 (Newcastle disease virus)

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    Dimitrov, Kiril M.; Ramey, Andy M.; Qiu, Xueting; Bahl, Justin; Afonso, Claudio L.

    2016-01-01

    Newcastle disease is caused by virulent forms of avian paramyxovirus of serotype 1 (APMV-1) and has global economic importance. The disease reached panzootic proportions within two decades after first being identified in 1926 in the United Kingdom and Indonesia and still remains endemic in many countries across the world. Here we review information on the host, temporal, and geographic distribution of APMV-1 genetic diversity based on the evolutionary systematics of the complete coding region of the fusion gene. Strains of APMV-1 are phylogenetically separated into two classes (class I and class II) and further classified into genotypes based on genetic differences. Class I viruses are genetically less diverse, generally present in wild waterfowl, and are of low virulence. Class II viruses are genetically and phenotypically more diverse, frequently isolated from poultry with occasional spillovers into wild birds, and exhibit a wider range of virulence. Waterfowl, cormorants, and pigeons are natural reservoirs of all APMV-1 pathotypes, except viscerotropic velogenic viruses for which natural reservoirs have not been identified. Genotypes I and II within class II include isolates of high and low virulence, the latter often being used as vaccines. Viruses of genotypes III and IX that emerged decades ago are now isolated rarely, but may be found in domestic and wild birds in China. Containing only virulent viruses and responsible for the majority of recent outbreaks in poultry and wild birds, viruses from genotypes V, VI, and VII, are highly mobile and have been isolated on different continents. Conversely, virulent viruses of genotypes XI (Madagascar), XIII (mainly Southwest Asia), XVI (North America) and XIV, XVII and XVIII (Africa) appear to have a more limited geographic distribution and have been isolated predominantly from poultry.

  7. Host and geographic structure of endophytic and endolichenic fungi at a continental scale.

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    U'Ren, Jana M; Lutzoni, François; Miadlikowska, Jolanta; Laetsch, Alexander D; Arnold, A Elizabeth

    2012-05-01

    Endophytic and endolichenic fungi occur in healthy tissues of plants and lichens, respectively, playing potentially important roles in the ecology and evolution of their hosts. However, previous sampling has not comprehensively evaluated the biotic, biogeographic, and abiotic factors that structure their communities. Using molecular data we examined the diversity, composition, and distributions of 4154 endophytic and endolichenic Ascomycota cultured from replicate surveys of ca. 20 plant and lichen species in each of five North American sites (Madrean coniferous forest, Arizona; montane semideciduous forest, North Carolina; scrub forest, Florida; Beringian tundra and forest, western Alaska; subalpine tundra, eastern central Alaska). Endolichenic fungi were more abundant and diverse per host species than endophytes, but communities of endophytes were more diverse overall, reflecting high diversity in mosses and lycophytes. Endophytes of vascular plants were largely distinct from fungal communities that inhabit mosses and lichens. Fungi from closely related hosts from different regions were similar in higher taxonomy, but differed at shallow taxonomic levels. These differences reflected climate factors more strongly than geographic distance alone. Our study provides a first evaluation of endophytic and endolichenic fungal associations with their hosts at a continental scale. Both plants and lichens harbor abundant and diverse fungal communities whose incidence, diversity, and composition reflect the interplay of climatic patterns, geographic separation, host type, and host lineage. Although culture-free methods will inform future work, our study sets the stage for empirical assessments of ecological specificity, metabolic capability, and comparative genomics.

  8. Identification of novel mammalian hosts and Brazilian biome geographic distribution of Trypanosoma cruzi TcIII and TcIV.

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    Barros, Juliana Helena S; Xavier, Samanta Cristina C; Bilac, Daniele; Lima, Valdirene Santos; Dario, Maria Augusta; Jansen, Ana Maria

    2017-08-01

    Trypanosoma cruzi is a parasitic protozoan responsible for Chagas disease. Seven different Discrete Typing Units (DTUs) of T. cruzi are currently identified in nature: TcI-TcVI, and TcBat whose distribution patterns in nature, hosts/reservoirs and eco-epidemiological importance are still little known. Here, we present novel data on the geographic distribution and diversity of mammalian hosts and vectors of T. cruzi DTUs TcIII and TcIV. In this study, we analyzed 61 T. cruzi isolates obtained from 18 species of mammals (five orders) and two Hemiptera genera. Samples were collected from five Brazilian biomes (Pantanal, Caatinga, Cerrado, Atlantic Rainforest, and Amazon) previously characterized as Z3 or mixed infection (TcI-Z3) by mini-exon gene PCR. To identify TcIII and TcIV genotypes, we applied restriction fragment length polymorphism analysis to the PCR-amplified histone 3 gene. DTUs TcIII and TcIV were identified in single and mixed infections from wide dispersion throughout five Brazilian biomes studied, with TcIV being the most common. Pantanal was the biome that displayed the largest number of samples characterized as TcIII and TcIV in single and mixed infections, followed by Atlantic Rainforest and Amazon. Species from the Didelphimorphia order displayed the highest frequency of infection and were found in all five biomes. We report, for the first time, the infection of a species of the Artiodactyla order by DTU TcIII. In addition, we describe new host species: five mammals (marsupials and rodents) and two genera of Hemiptera. Our data indicate that DTUs TcIII and TcIV are more widespread and infect a larger number of mammalian species than previously thought. In addition, they are transmitted in restricted foci and cycles, but in different microhabitats and areas with distinct ecological profiles. Finally, we show that DTUs TcIII and TcIV do not present any specific association with biomes or host species. Copyright © 2017. Published by Elsevier B.V.

  9. Analysis of host preference and geographical distribution of Anastrepha suspensa (Diptera: Tephritidae) using phylogenetic analyses of mitochondrial cytochrome oxidase I DNA sequence data.

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    Boykin, L M; Shatters, R G; Hall, D G; Burns, R E; Franqui, R A

    2006-10-01

    Anastrepha suspensa (Loew) is an economically important pest, restricted to the Greater Antilles and southern Florida. It infests a wide variety of hosts and is of quarantine importance in citrus, a multi-million dollar industry in Florida. The observed recent increase in citrus infested with A. suspensa in Florida has raised questions regarding host-specificity of certain populations and genetic diversity of the pest throughout its geographical distribution. Cytochrome oxidase I (COI) DNA sequence data was used to characterize the genetic diversity of A. suspensa from Florida and Caribbean populations reared from different host plants. Maximum likelihood and Bayesian phylogenetic methods were used to analyse COI data. Sequence variation among mitochondrial COI genes from 107 A. suspensa samples collected throughout Florida and the Caribbean ranged between 0 and 10% and placed all A. suspensa as a monophyletic group that united all A. suspensa in a clade sister to a Central American group of the A. fraterculus paraphyletic species complex. The most likely tree of the COI locus indicated that COI sequence variation was too low to provide resolution at the subspecies level, therefore monophyletic groups based on host-plant use, geography (Florida, Jamaica, Cayman Islands, Puerto Rico or Dominican Republic) or population sampled are not supported. This result indicates that either no population segregation has occurred based on these biological or geographical distinctions and that this is a generalist, polyphagous invasive genotype. Alternatively, if populations are distinct, the segregation event was more recent than can be distinguished based on COI sequence variation.

  10. Host range, host ecology, and distribution of more than 11800 fish parasite species

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    Strona, Giovanni; Palomares, Maria Lourdes D.; Bailly, Nicholas; Galli, Paolo; Lafferty, Kevin D.

    2013-01-01

    Our data set includes 38 008 fish parasite records (for Acanthocephala, Cestoda, Monogenea, Nematoda, Trematoda) compiled from the scientific literature, Internet databases, and museum collections paired to the corresponding host ecological, biogeographical, and phylogenetic traits (maximum length, growth rate, life span, age at maturity, trophic level, habitat preference, geographical range size, taxonomy). The data focus on host features, because specific parasite traits are not consistently available across records. For this reason, the data set is intended as a flexible resource able to extend the principles of ecological niche modeling to the host–parasite system, providing researchers with the data to model parasite niches based on their distribution in host species and the associated host features. In this sense, the database offers a framework for testing general ecological, biogeographical, and phylogenetic hypotheses based on the identification of hosts as parasite habitat. Potential applications of the data set are, for example, the investigation of species–area relationships or the taxonomic distribution of host-specificity. The provided host–parasite list is that currently used by Fish Parasite Ecology Software Tool (FishPEST, http://purl.oclc.org/fishpest), which is a website that allows researchers to model several aspects of the relationships between fish parasites and their hosts. The database is intended for researchers who wish to have more freedom to analyze the database than currently possible with FishPEST. However, for readers who have not seen FishPEST, we recommend using this as a starting point for interacting with the database.

  11. Determinants of Dentists' Geographic Distribution.

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    Beazoglou, Tryfon J.; And Others

    1992-01-01

    A model for explaining the geographic distribution of dentists' practice locations is presented and applied to particular market areas in Connecticut. Results show geographic distribution is significantly related to a few key variables, including demography, disposable income, and housing prices. Implications for helping students make practice…

  12. Babesia vesperuginis, a neglected piroplasmid: new host and geographical records, and phylogenetic relations.

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    Corduneanu, Alexandra; Hrazdilová, Kristýna; Sándor, Attila D; Matei, Ioana Adriana; Ionică, Angela Monica; Barti, Levente; Ciocănău, Marius-Alexandru; Măntoiu, Dragoş Ștefan; Coroiu, Ioan; Hornok, Sándor; Fuehrer, Hans-Peter; Leitner, Natascha; Bagó, Zoltán; Stefke, Katharina; Modrý, David; Mihalca, Andrei Daniel

    2017-12-06

    Babesia spp. are hemoparasites which infect the red blood cells of a large variety of mammals. In bats, the only known species of the genus is Babesia vesperuginis. However, except a few old reports, the host range and geographical distribution of this bat parasite have been poorly studied. This study aimed to investigate the presence of piroplasms in tissues of bats collected in four different countries from eastern and central Europe: Austria, Czech Republic, Hungary and Romania. A total of 461 bat carcasses (24 species) were collected between 2001 and 2016 from caves, mines and buildings. PCR was performed using specific primers targeting a portion of the 18S rDNA nuclear gene and cytochrome c oxidase subunit 1 mitochondrial gene, followed by sequencing. The results of this study show for the first time the presence of B. vesperuginis in bats in central and eastern Europe. The phylogenetic analysis of the 18S rDNA nuclear gene revealed no variability between the sequences and the phylogenetic analysis of the cox1 mitochondrial gene proved that B. vesperuginis could be divided into two subclades. Our study showed a broad geographical distribution of B. vesperuginis in European bats, reporting its presence in five new host species (M. cf. alcathoe, M. bechsteinii, M. myotis, Pi. nathusii and V. murinus) and three new countries.

  13. Mesoniviruses are mosquito-specific viruses with extensive geographic distribution and host range.

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    Vasilakis, Nikos; Guzman, Hilda; Firth, Cadhla; Forrester, Naomi L; Widen, Steven G; Wood, Thomas G; Rossi, Shannan L; Ghedin, Elodie; Popov, Vsevolov; Blasdell, Kim R; Walker, Peter J; Tesh, Robert B

    2014-05-20

    The family Mesoniviridae (order Nidovirales) comprises of a group of positive-sense, single-stranded RNA ([+]ssRNA) viruses isolated from mosquitoes. Thirteen novel insect-specific virus isolates were obtained from mosquitoes collected in Indonesia, Thailand and the USA. By electron microscopy, the virions appeared as spherical particles with a diameter of ~50 nm. Their 20,129 nt to 20,777 nt genomes consist of positive-sense, single-stranded RNA with a poly-A tail. Four isolates from Houston, Texas, and one isolate from Java, Indonesia, were identified as variants of the species Alphamesonivirus-1 which also includes Nam Dinh virus (NDiV) from Vietnam and Cavally virus (CavV) from Côte d'Ivoire. The eight other isolates were identified as variants of three new mesoniviruses, based on genome organization and pairwise evolutionary distances: Karang Sari virus (KSaV) from Java, Bontag Baru virus (BBaV) from Java and Kalimantan, and Kamphaeng Phet virus (KPhV) from Thailand. In comparison with NDiV, the three new mesoniviruses each contained a long insertion (180 - 588 nt) of unknown function in the 5' region of ORF1a, which accounted for much of the difference in genome size. The insertions contained various short imperfect repeats and may have arisen by recombination or sequence duplication. In summary, based on their genome organizations and phylogenetic relationships, thirteen new viruses were identified as members of the family Mesoniviridae, order Nidovirales. Species demarcation criteria employed previously for mesoniviruses would place five of these isolates in the same species as NDiV and CavV (Alphamesonivirus-1) and the other eight isolates would represent three new mesonivirus species (Alphamesonivirus-5, Alphamesonivirus-6 and Alphamesonivirus-7). The observed spatiotemporal distribution over widespread geographic regions and broad species host range in mosquitoes suggests that mesoniviruses may be common in mosquito populations worldwide.

  14. Unexpected absence of genetic separation of a highly diverse population of hookworms from geographically isolated hosts.

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    Haynes, Benjamin T; Marcus, Alan D; Higgins, Damien P; Gongora, Jaime; Gray, Rachael; Šlapeta, Jan

    2014-12-01

    The high natal site fidelity of endangered Australian sea lions (Neophoca cinerea) along the southern Australian coast suggests that their maternally transmitted parasitic species, such as hookworms, will have restricted potential for dispersal. If this is the case, we would expect to find a hookworm haplotype structure corresponding to that of the host mtDNA haplotype structure; that is, restricted among geographically separated colonies. In this study, we used a fragment of the cytochrome c oxidase I mitochondrial DNA (mtDNA) gene to investigate the diversity of hookworms (Uncinaria sanguinis) in N. cinerea to assess the importance of host distribution and ecology on the evolutionary history of the parasite. High haplotype (h=0.986) and nucleotide diversity (π=0.013) were seen, with 45 unique hookworm mtDNA haplotypes across N. cinerea colonies; with most of the variation (78%) arising from variability within hookworms from individual colonies. This is supported by the low genetic differentiation co-efficient (GST=0.007) and a high gene flow (Nm=35.25) indicating a high migration rate between the populations of hookworms. The haplotype network demonstrated no clear distribution and delineation of haplotypes according to geographical location. Our data rejects the vicariance hypothesis; that female host natal site fidelity and the transmammary route of infection restrict hookworm gene flow between N. cinerea populations and highlights the value of studies of parasite diversity and dispersal to challenge our understanding of parasite and host ecology. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Genetic diversity and distribution patterns of host insects of Caterpillar Fungus Ophiocordyceps sinensis in the Qinghai-Tibet Plateau.

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    Quan, Qing-Mei; Chen, Ling-Ling; Wang, Xi; Li, Shan; Yang, Xiao-Ling; Zhu, Yun-Guo; Wang, Mu; Cheng, Zhou

    2014-01-01

    The caterpillar fungus Ophiocordyceps sinensis is one of the most valuable medicinal fungi in the world, and it requires host insects in family Hepialidae (Lepidoptera) to complete its life cycle. However, the genetic diversity and phylogeographic structures of the host insects remain to be explored. We analyzed the genetic diversity and temporal and spatial distribution patterns of genetic variation of the host insects throughout the O. sinensis distribution. Abundant haplotype and nucleotide diversity mainly existed in the areas of Nyingchi, ShangriLa, and around the edge of the Qinghai-Tibet Plateau, where are considered as the diversity center or micro-refuges of the host insects of O. sinensis. However, there was little genetic variation among host insects from 72.1% of all populations, indicating that the host species composition might be relatively simple in large-scale O. sinensis populations. All host insects are monophyletic except for those from four O. sinensis populations around Qinghai Lake. Significant phylogeographic structure (NST>GST, Pinsects, and the three major phylogenetic groups corresponded with specific geographical areas. The divergence of most host insects was estimated to have occurred at ca. 3.7 Ma, shortly before the rapid uplift of the QTP. The geographical distribution and star-like network of the haplotypes implied that most host insects were derived from the relicts of a once-widespread host that subsequently became fragmented. Neutrality tests, mismatch distribution analysis, and expansion time estimation confirmed that most host insects presented recent demographic expansions that began ca. 0.118 Ma in the late Pleistocene. Therefore, the genetic diversity and distribution of the present-day insects should be attributed to effects of the Qinghai-Tibet Plateau uplift and glacial advance/retreat cycles during the Quaternary ice age. These results provide valuable information to guide the protection and sustainable use of these host

  16. Geographical distribution of a specific mitochondrial haplotype of Zymoseptoria tritici

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    Sameh BOUKEF

    2014-01-01

    Full Text Available Severity of disease caused by the fungus Zymoseptoria tritici throughout world cereal growing regions has elicited much debate on the potential evolutionary mechanism conferring high adaptability of the pathogen to diverse climate conditions and different wheat hosts (Triticum durum and T. aestivum. Specific mitochondrial DNA sequence was used to investigate geographic distribution of the type 4 haplotype (mtRFLP4 within 1363 isolates of Z. tritici originating from 21 countries. The mtRFLP4 haplotype was detected from both durum and bread wheat hosts with greater frequency on durum wheat. The distribution of mtRFLP4 was limited to populations sampled from the Mediterranean and the Red Sea region. Greater frequencies of mtRFLP4 were found in Tunisia (87% and Algeria (60%. The haplotype was absent within European, Australian, North and South American populations except Argentina. While alternative hypotheses such as climatic adaptation could not be ruled out, it is postulated that mtRFLP4 originated in North Africa (e.g. Tunisia or Algeria as an adaptation to durum wheat as the prevailing cereal crop. The specialized haplotype has subsequently spread as indicated by lower frequency of occurrence in the surrounding Mediterranean countries and on bread wheat hosts.

  17. Genetic diversity and distribution patterns of host insects of Caterpillar Fungus Ophiocordyceps sinensis in the Qinghai-Tibet Plateau.

    Directory of Open Access Journals (Sweden)

    Qing-Mei Quan

    Full Text Available The caterpillar fungus Ophiocordyceps sinensis is one of the most valuable medicinal fungi in the world, and it requires host insects in family Hepialidae (Lepidoptera to complete its life cycle. However, the genetic diversity and phylogeographic structures of the host insects remain to be explored. We analyzed the genetic diversity and temporal and spatial distribution patterns of genetic variation of the host insects throughout the O. sinensis distribution. Abundant haplotype and nucleotide diversity mainly existed in the areas of Nyingchi, ShangriLa, and around the edge of the Qinghai-Tibet Plateau, where are considered as the diversity center or micro-refuges of the host insects of O. sinensis. However, there was little genetic variation among host insects from 72.1% of all populations, indicating that the host species composition might be relatively simple in large-scale O. sinensis populations. All host insects are monophyletic except for those from four O. sinensis populations around Qinghai Lake. Significant phylogeographic structure (NST>GST, P<0.05 was revealed for the monophyletic host insects, and the three major phylogenetic groups corresponded with specific geographical areas. The divergence of most host insects was estimated to have occurred at ca. 3.7 Ma, shortly before the rapid uplift of the QTP. The geographical distribution and star-like network of the haplotypes implied that most host insects were derived from the relicts of a once-widespread host that subsequently became fragmented. Neutrality tests, mismatch distribution analysis, and expansion time estimation confirmed that most host insects presented recent demographic expansions that began ca. 0.118 Ma in the late Pleistocene. Therefore, the genetic diversity and distribution of the present-day insects should be attributed to effects of the Qinghai-Tibet Plateau uplift and glacial advance/retreat cycles during the Quaternary ice age. These results provide valuable

  18. The geographical vector in distribution of genetic diversity for Clonorchis sinensis.

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    Solodovnik, Daria A; Tatonova, Yulia V; Burkovskaya, Polina V

    2018-01-01

    Clonorchis sinensis, the causative agent of clonorchiasis, is one of the most important parasites that inhabit countries of East and Southeast Asia. In this study, we validated the existence of a geographical vector for C. sinensis using the partial cox1 mtDNA gene, which includes a conserved region. The samples of parasite were divided into groups corresponding to three river basins, and the size of the conserved region had a strong tendency to increase from the northernmost to the southernmost samples. This indicates the availability of the geographical vector in distribution of genetic diversity. A vector is a quantity that is characterized by magnitude and direction. Geographical vector obtained in cox1 gene of C. sinensis has both these features. The reasons for the occurrence of this feature, including the influence of intermediate and definitive hosts on vector formation, and the possibility of its use for clonorchiasis monitoring are discussed. Graphical abstract ᅟ.

  19. Diversity and Geographical Distribution of Flavobacterium psychrophilum Isolates and Their Phages: Patterns of Susceptibility to Phage Infection and Phage Host Range

    DEFF Research Database (Denmark)

    Castillo, Daniel; Christiansen, Rói Hammershaimb; Espejo, Romilio

    2014-01-01

    in disease control requires detailed knowledge about the diversity and dynamics of host susceptibility to phage infection. For this reason, we examined the genetic diversity of 49 F. psychrophilum strains isolated in three different areas (Chile, Denmark, and USA) through direct genome restriction enzyme...... analysis (DGREA) and their susceptibility to 33 bacteriophages isolated in Chile and Denmark, thus covering large geographical (>12,000 km) and temporal (>60 years) scales of isolation. An additional 40 phage-resistant isolates obtained from culture experiments after exposure to specific phages were...... examined for changes in phage susceptibility against the 33 phages. The F. psychrophilum and phage populations isolated from Chile and Denmark clustered into geographically distinct groups with respect to DGREA profile and host range, respectively. However, cross infection between Chilean phage isolates...

  20. Diversity, Host Specialization, and Geographic Structure of Filarial Nematodes Infecting Malagasy Bats.

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    Ramasindrazana, Beza; Dellagi, Koussay; Lagadec, Erwan; Randrianarivelojosia, Milijaona; Goodman, Steven M; Tortosa, Pablo

    2016-01-01

    We investigated filarial infection in Malagasy bats to gain insights into the diversity of these parasites and explore the factors shaping their distribution. Samples were obtained from 947 individual bats collected from 52 sites on Madagascar and representing 31 of the 44 species currently recognized on the island. Samples were screened for the presence of micro- and macro-parasites through both molecular and morphological approaches. Phylogenetic analyses showed that filarial diversity in Malagasy bats formed three main groups, the most common represented by Litomosa spp. infecting Miniopterus spp. (Miniopteridae); a second group infecting Pipistrellus cf. hesperidus (Vespertilionidae) embedded within the Litomosoides cluster, which is recognized herein for the first time from Madagascar; and a third group composed of lineages with no clear genetic relationship to both previously described filarial nematodes and found in M. griveaudi, Myotis goudoti, Neoromicia matroka (Vespertilionidae), Otomops madagascariensis (Molossidae), and Paratriaenops furculus (Hipposideridae). We further analyzed the infection rates and distribution pattern of Litomosa spp., which was the most diverse and prevalent filarial taxon in our sample. Filarial infection was disproportionally more common in males than females in Miniopterus spp., which might be explained by some aspect of roosting behavior of these cave-dwelling bats. We also found marked geographic structure in the three Litomosa clades, mainly linked to bioclimatic conditions rather than host-parasite associations. While this study demonstrates distinct patterns of filarial nematode infection in Malagasy bats and highlights potential drivers of associated geographic distributions, future work should focus on their alpha taxonomy and characterize arthropod vectors.

  1. Diversity, Host Specialization, and Geographic Structure of Filarial Nematodes Infecting Malagasy Bats.

    Directory of Open Access Journals (Sweden)

    Beza Ramasindrazana

    Full Text Available We investigated filarial infection in Malagasy bats to gain insights into the diversity of these parasites and explore the factors shaping their distribution. Samples were obtained from 947 individual bats collected from 52 sites on Madagascar and representing 31 of the 44 species currently recognized on the island. Samples were screened for the presence of micro- and macro-parasites through both molecular and morphological approaches. Phylogenetic analyses showed that filarial diversity in Malagasy bats formed three main groups, the most common represented by Litomosa spp. infecting Miniopterus spp. (Miniopteridae; a second group infecting Pipistrellus cf. hesperidus (Vespertilionidae embedded within the Litomosoides cluster, which is recognized herein for the first time from Madagascar; and a third group composed of lineages with no clear genetic relationship to both previously described filarial nematodes and found in M. griveaudi, Myotis goudoti, Neoromicia matroka (Vespertilionidae, Otomops madagascariensis (Molossidae, and Paratriaenops furculus (Hipposideridae. We further analyzed the infection rates and distribution pattern of Litomosa spp., which was the most diverse and prevalent filarial taxon in our sample. Filarial infection was disproportionally more common in males than females in Miniopterus spp., which might be explained by some aspect of roosting behavior of these cave-dwelling bats. We also found marked geographic structure in the three Litomosa clades, mainly linked to bioclimatic conditions rather than host-parasite associations. While this study demonstrates distinct patterns of filarial nematode infection in Malagasy bats and highlights potential drivers of associated geographic distributions, future work should focus on their alpha taxonomy and characterize arthropod vectors.

  2. The geographical distribution and habitats of three liver fluke intermediate hosts in South - Africa and the health implications involved

    Directory of Open Access Journals (Sweden)

    K. N. de Kock

    2008-09-01

    persons and authorities were totally unsuccessful. In view of statistics available for elsewhere in the world, it would be unwise to assume that no problems exist in this regard in South Africa. The number of people suffering from fasciolosis was already estimated at 2.4 million in 61 countries in 1995 and another 180 million at risk of becoming infected, with the highest prevalence’s reported from Bolivia, China, Ecuador, Egypt, France, Iran, Peru and Portugal. The results of recent serological assays for the detection of fasciolosis in cattle herds in selected areas in South Africa indicated positive cases from localities that closely correspond to the geographical distribution of the three Lymnaea species in this country. According to reports in the literature, the high prevalence of fasciolosis in livestock in the highlands of Ethiopia couldhave serious health implications for people in the area because they have to use the same water resources. In many rural areas in South Africa local populations also have no other options than to share natural water resources with their livestock. In most instances these water bodies harbour at least one of the Lymnaea species which can maintain the life cycle of fasciola. Under such conditions residents could daily be exposed to the risk of becoming infected. It is a matter of concern that epidemiological research with regard to human fasciolosis is such aneglected subject in South Africa. In our opinion epidemiological surveys should be conducted to determine the prevalence of human fasciolosis in specific areas which could be selected on the basis of using the geographical distribution of the three Linnaean species as guidelines. Efforts should also be made to conduct surveys to update the geographical distribution of the snail intermediate hosts and awareness programmes should be launched in rural areas at risk.

  3. Large-scale determinants of intestinal schistosomiasis and intermediate host snail distribution across Africa: does climate matter?

    Science.gov (United States)

    Stensgaard, Anna-Sofie; Utzinger, Jürg; Vounatsou, Penelope; Hürlimann, Eveline; Schur, Nadine; Saarnak, Christopher F L; Simoonga, Christopher; Mubita, Patricia; Kabatereine, Narcis B; Tchuem Tchuenté, Louis-Albert; Rahbek, Carsten; Kristensen, Thomas K

    2013-11-01

    The geographical ranges of most species, including many infectious disease agents and their vectors and intermediate hosts, are assumed to be constrained by climatic tolerances, mainly temperature. It has been suggested that global warming will cause an expansion of the areas potentially suitable for infectious disease transmission. However, the transmission of infectious diseases is governed by a myriad of ecological, economic, evolutionary and social factors. Hence, a deeper understanding of the total disease system (pathogens, vectors and hosts) and its drivers is important for predicting responses to climate change. Here, we combine a growing degree day model for Schistosoma mansoni with species distribution models for the intermediate host snail (Biomphalaria spp.) to investigate large-scale environmental determinants of the distribution of the African S. mansoni-Biomphalaria system and potential impacts of climatic changes. Snail species distribution models included several combinations of climatic and habitat-related predictors; the latter divided into "natural" and "human-impacted" habitat variables to measure anthropogenic influence. The predictive performance of the combined snail-parasite model was evaluated against a comprehensive compilation of historical S. mansoni parasitological survey records, and then examined for two climate change scenarios of increasing severity for 2080. Future projections indicate that while the potential S. mansoni transmission area expands, the snail ranges are more likely to contract and/or move into cooler areas in the south and east. Importantly, we also note that even though climate per se matters, the impact of humans on habitat play a crucial role in determining the distribution of the intermediate host snails in Africa. Thus, a future contraction in the geographical range size of the intermediate host snails caused by climatic changes does not necessarily translate into a decrease or zero-sum change in human

  4. Tick parasites of rodents in Romania: host preferences, community structure and geographical distribution.

    Science.gov (United States)

    Mihalca, Andrei D; Dumitrache, Mirabela O; Sándor, Attila D; Magdaş, Cristian; Oltean, Miruna; Györke, Adriana; Matei, Ioana A; Ionică, Angela; D'Amico, Gianluca; Cozma, Vasile; Gherman, Călin M

    2012-11-21

    Ticks are among the most important vectors of zoonotic diseases in temperate regions of Europe, with widespread distribution and high densities, posing an important medical risk. Most ticks feed on a variety of progressively larger hosts, with a large number of small mammal species typically harbouring primarily the immature stages. However, there are certain Ixodidae that characteristically attack micromammals also during their adult stage. Rodents are widespread hosts of ticks, important vectors and competent reservoirs of tick-borne pathogens. Micromammal-tick associations have been poorly studied in Romania, and our manuscript shows the results of a large scale study on tick infestation epidemiology in rodents from Romania. Rodents were caught using snap-traps in a variety of habitats in Romania, between May 2010 and November 2011. Ticks were individually collected from these rodents and identified to species and development stage. Frequency, mean intensity, prevalence and its 95% confidence intervals were calculated using the EpiInfo 2000 software. A p value of Romania for the presence of ticks. Each collected tick was identified to species level and the following epidemiological parameters were calculated: prevalence, mean intensity and mean abundance. The total number of ticks collected from rodents was 483, with eight species identified: Ixodes ricinus, I. redikorzevi, I. apronophorus, I. trianguliceps, I. laguri, Dermacentor marginatus, Rhipicephalus sanguineus and Haemaphysalis sulcata. The overall prevalence of tick infestation was 29.55%, with a mean intensity of 3.86 and a mean abundance of 1.14. Only two polyspecific infestations were found: I. ricinus + I. redikorzevi and I. ricinus + D. marginatus. Our study showed a relatively high diversity of ticks parasitizing rodents in Romania. The most common tick in rodents was I. ricinus, followed by I. redikorzevi. Certain rodents seem to host a significantly higher number of tick species than others, the

  5. Large-scale determinants of intestinal schistosomiasis and intermediate host snail distribution across Africa

    DEFF Research Database (Denmark)

    Stensgaard, Anna-Sofie; Utzinger, Jürg; Vounatsou, Penelope

    2013-01-01

    The geographical ranges of most species, including many infectious disease agents and their vectors and intermediate hosts, are assumed to be constrained by climatic tolerances, mainly temperature. It has been suggested that global warming will cause an expansion of the areas potentially suitable...... impacts of climatic changes. Snail species distribution models included several combinations of climatic and habitat-related predictors; the latter divided into "natural" and "human-impacted" habitat variables to measure anthropogenic influence. The predictive performance of the combined snail...... are more likely to contract and/or move into cooler areas in the south and east. Importantly, we also note that even though climate per se matters, the impact of humans on habitat play a crucial role in determining the distribution of the intermediate host snails in Africa. Thus, a future contraction...

  6. The geographical distribution of tremellaceous fungi in Poland

    Directory of Open Access Journals (Sweden)

    Władysław Wojewoda

    2014-11-01

    Full Text Available The geographical distribution of the Polish tremellaceous fungi is discussed in this paper. The list of localities and the maps of the distribution of 60 Polish species (45 of Tremellales, 13 of Auriculariales and 2 of Septobasidiales are given. The author distinguishes several geographical elements, and describes the vertical distribution of these fungi. This paper is a supplement to "Fungi (Mycota", vol. 8, Polish Flora (Wojewoda 1977.

  7. First Record of Transversotrema Witenberg, 1944 (Digenea) from the Americas, with Comments on the Taxonomy of Transversotrema patialense (Soparkar, 1924) Crusz and Sathananthan, 1960, and an Updated List of Its Hosts and Geographic Distribution.

    Science.gov (United States)

    Womble, Matthew R; Cox-Gardiner, Stephanie J; Cribb, Thomas H; Bullard, Stephen A

    2015-12-01

    Specimens of Transversotrema patialense (sensu lato) ( Soparkar, 1924 ) Crusz and Sathananthan, 1960 (Digenea: Transversotrematidae) infected the skin (epidermal spaces beneath scales near pectoral fins) of 4 of 126 (prevalence 3%; mean intensity 1.8) zebrafish ( Danio rerio (Hamilton, 1822) [Cypriniformes: Cyprinidae]) purchased in 2009 and cultured by a California (USA) fish supplier. These fish were sold as "laboratory-reared" and "specific pathogen free," purportedly raised in a recirculating aquaculture system that included zebrafish only. We herein describe the morphological features of this transversotrematid using light and scanning electron microscopy, provide a comprehensive list of hosts (snails and fishes) and geographic locality records for specimens reported as T. patialense, which is perhaps a species complex, and provide a brief historical synopsis of the taxonomic and life history research that has been conducted on this fluke. No species of Transversotrema previously had been reported from the Americas; however, this discovery is not surprising given that: (1) a suitable intermediate host (red-rimmed melania, Melanoides tuberculata (Müller, 1774) [Cerithioidea: Thiaridae]) has been established in California and elsewhere in North America, (2) the zebrafish is a susceptible definitive host, and (3) T. patialense reportedly matures on a broad ecological and phylogenetic spectrum of freshwater fishes. To our knowledge, this is the northern-most geographic locality record for a species of this genus. We suspect this case study represents an example of a parasite that may now be established in North America by the fortuitous co-occurrence of a susceptible, exotic snail host (the red-rimmed melania) and a susceptible, widely distributed, exotic fish host (the zebrafish).

  8. Toxocariasis in Carnivora from Argentinean Patagonia: Species molecular identification, hosts, and geographical distribution

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    R.M. Vega

    2018-04-01

    Full Text Available Twenty four specimens of seven species belonging to the families Felidae, Mustelidae, and Canidae were obtained in Lanín and Nahuel Huapi National Parks from March 1996 to April 2016. Specimens were processed by necropsy in order to contribute to the knowledge of toxocariasis in wild carnivores of Argentinean Patagonia. The only Puma concolor and the seven Leopardus geoffroyi were positive for Toxocara cati. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP of the ITS-1 region from larval and adult DNA was carried out to confirm parasite species identification. This is the first molecular determination of T. cati from wild felids in Argentina and the study also fill gaps about the spatial distribution and hosts for Toxocara cati. Keywords: Toxocara cati, Puma concolor, Leopardus geoffroyi, Molecular identification, Argentina

  9. Driving forces for changes in geographical distribution of Ixodes ricinus ticks in Europe

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    Medlock Jolyon M

    2013-01-01

    Full Text Available Abstract Many factors are involved in determining the latitudinal and altitudinal spread of the important tick vector Ixodes ricinus (Acari: Ixodidae in Europe, as well as in changes in the distribution within its prior endemic zones. This paper builds on published literature and unpublished expert opinion from the VBORNET network with the aim of reviewing the evidence for these changes in Europe and discusses the many climatic, ecological, landscape and anthropogenic drivers. These can be divided into those directly related to climatic change, contributing to an expansion in the tick’s geographic range at extremes of altitude in central Europe, and at extremes of latitude in Scandinavia; those related to changes in the distribution of tick hosts, particularly roe deer and other cervids; other ecological changes such as habitat connectivity and changes in land management; and finally, anthropogenically induced changes. These factors are strongly interlinked and often not well quantified. Although a change in climate plays an important role in certain geographic regions, for much of Europe it is non-climatic factors that are becoming increasingly important. How we manage habitats on a landscape scale, and the changes in the distribution and abundance of tick hosts are important considerations during our assessment and management of the public health risks associated with ticks and tick-borne disease issues in 21st century Europe. Better understanding and mapping of the spread of I. ricinus (and changes in its abundance is, however, essential to assess the risk of the spread of infections transmitted by this vector species. Enhanced tick surveillance with harmonized approaches for comparison of data enabling the follow-up of trends at EU level will improve the messages on risk related to tick-borne diseases to policy makers, other stake holders and to the general public.

  10. Geographical variation in host-ant specificity of the parasitic butterfly Maculinea alcon in Denmark

    DEFF Research Database (Denmark)

    Als, Thomas Damm; Nash, David Richard; Boomsma, J. J.

    2002-01-01

    1. Maculinea alcon uses three different species of Myrmica host ants along a north-south gradient in Europe. Based on this geographical variation in host ant use, Elmes et al. (1994) suggested that M. alcon might consist of three or more cryptic species or host races, each using a single...... and different host-ant species.2. Population-specific differences in allozyme genotypes of M. alcon in Denmark (Gadeberg Boomsma, 1997) have suggested that genetically differentiated forms may occur in a gradient across Denmark, possibly in relation to the use of different host ants.3. It was found that two...... host-ant species are indeed used as hosts in Denmark, but not in a clear-cut north-south gradient. Furthermore, specificity was not complete for many M. alcon populations. Of five populations investigated in detail, one used primarily M. rubra as a host, another exclusively used M. ruginodis, while...

  11. Community structure informs species geographic distributions

    KAUST Repository

    Montesinos-Navarro, Alicia

    2018-05-23

    Understanding what determines species\\' geographic distributions is crucial for assessing global change threats to biodiversity. Measuring limits on distributions is usually, and necessarily, done with data at large geographic extents and coarse spatial resolution. However, survival of individuals is determined by processes that happen at small spatial scales. The relative abundance of coexisting species (i.e. \\'community structure\\') reflects assembly processes occurring at small scales, and are often available for relatively extensive areas, so could be useful for explaining species distributions. We demonstrate that Bayesian Network Inference (BNI) can overcome several challenges to including community structure into studies of species distributions, despite having been little used to date. We hypothesized that the relative abundance of coexisting species can improve predictions of species distributions. In 1570 assemblages of 68 Mediterranean woody plant species we used BNI to incorporate community structure into Species Distribution Models (SDMs), alongside environmental information. Information on species associations improved SDM predictions of community structure and species distributions moderately, though for some habitat specialists the deviance explained increased by up to 15%. We demonstrate that most species associations (95%) were positive and occurred between species with ecologically similar traits. This suggests that SDM improvement could be because species co-occurrences are a proxy for local ecological processes. Our study shows that Bayesian Networks, when interpreted carefully, can be used to include local conditions into measurements of species\\' large-scale distributions, and this information can improve the predictions of species distributions.

  12. Execution Management Solutions for Geographically Distributed Simulations

    NARCIS (Netherlands)

    Berg, T.W. van den; Jansen, H.G.M.; Jansen, R.E.J.; Prins, L.M.

    2009-01-01

    Managing the initialization, execution control and monitoring of HLA federates is not always straightforward, especially for a geographically distributed time managed federation. Issues include pre and post run-time data distribution and run-time data collection; starting, stopping and monitoring

  13. Geographically structured host specificity is caused by the range expansions and host shifts of a symbiotic fungus.

    Science.gov (United States)

    Wolfe, Benjamin E; Pringle, Anne

    2012-04-01

    The inability to associate with local species may constrain the spread of mutualists arriving to new habitats, but the fates of introduced, microbial mutualists are largely unknown. The deadly poisonous ectomycorrhizal fungus Amanita phalloides (the death cap) is native to Europe and introduced to the East and West Coasts of North America. By cataloging host associations across the two continents, we record dramatic changes in specificity among the three ranges. On the East Coast, where the fungus is restricted in its distribution, it associates almost exclusively with pines, which are rarely hosts of A. phalloides in its native range. In California, where the fungus is widespread and locally abundant, it associates almost exclusively with oaks, mirroring the host associations observed in Europe. The most common host of the death cap in California is the endemic coast live oak (Quercus agrifolia), and the current distribution of A. phalloides appears constrained within the distribution of Q. agrifolia. In California, host shifts to native plants are also associated with a near doubling in the resources allocated to sexual reproduction and a prolonged fruiting period; mushrooms are twice as large as they are elsewhere and mushrooms are found throughout the year. Host and niche shifts are likely to shape the continuing range expansion of A. phalloides and other ectomycorrhizal fungi introduced across the world.

  14. Selectivity by host plants affects the distribution of arbuscular mycorrhizal fungi: evidence from ITS rDNA sequence metadata

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    Yang Haishui

    2012-04-01

    Full Text Available Abstract Background Arbuscular mycorrhizal fungi (AMF can form obligate symbioses with the vast majority of land plants, and AMF distribution patterns have received increasing attention from researchers. At the local scale, the distribution of AMF is well documented. Studies at large scales, however, are limited because intensive sampling is difficult. Here, we used ITS rDNA sequence metadata obtained from public databases to study the distribution of AMF at continental and global scales. We also used these sequence metadata to investigate whether host plant is the main factor that affects the distribution of AMF at large scales. Results We defined 305 ITS virtual taxa (ITS-VTs among all sequences of the Glomeromycota by using a comprehensive maximum likelihood phylogenetic analysis. Each host taxonomic order averaged about 53% specific ITS-VTs, and approximately 60% of the ITS-VTs were host specific. Those ITS-VTs with wide host range showed wide geographic distribution. Most ITS-VTs occurred in only one type of host functional group. The distributions of most ITS-VTs were limited across ecosystem, across continent, across biogeographical realm, and across climatic zone. Non-metric multidimensional scaling analysis (NMDS showed that AMF community composition differed among functional groups of hosts, and among ecosystem, continent, biogeographical realm, and climatic zone. The Mantel test showed that AMF community composition was significantly correlated with plant community composition among ecosystem, among continent, among biogeographical realm, and among climatic zone. The structural equation modeling (SEM showed that the effects of ecosystem, continent, biogeographical realm, and climatic zone were mainly indirect on AMF distribution, but plant had strongly direct effects on AMF. Conclusion The distribution of AMF as indicated by ITS rDNA sequences showed a pattern of high endemism at large scales. This pattern indicates high specificity

  15. Selectivity by host plants affects the distribution of arbuscular mycorrhizal fungi: evidence from ITS rDNA sequence metadata.

    Science.gov (United States)

    Yang, Haishui; Zang, Yanyan; Yuan, Yongge; Tang, Jianjun; Chen, Xin

    2012-04-12

    Arbuscular mycorrhizal fungi (AMF) can form obligate symbioses with the vast majority of land plants, and AMF distribution patterns have received increasing attention from researchers. At the local scale, the distribution of AMF is well documented. Studies at large scales, however, are limited because intensive sampling is difficult. Here, we used ITS rDNA sequence metadata obtained from public databases to study the distribution of AMF at continental and global scales. We also used these sequence metadata to investigate whether host plant is the main factor that affects the distribution of AMF at large scales. We defined 305 ITS virtual taxa (ITS-VTs) among all sequences of the Glomeromycota by using a comprehensive maximum likelihood phylogenetic analysis. Each host taxonomic order averaged about 53% specific ITS-VTs, and approximately 60% of the ITS-VTs were host specific. Those ITS-VTs with wide host range showed wide geographic distribution. Most ITS-VTs occurred in only one type of host functional group. The distributions of most ITS-VTs were limited across ecosystem, across continent, across biogeographical realm, and across climatic zone. Non-metric multidimensional scaling analysis (NMDS) showed that AMF community composition differed among functional groups of hosts, and among ecosystem, continent, biogeographical realm, and climatic zone. The Mantel test showed that AMF community composition was significantly correlated with plant community composition among ecosystem, among continent, among biogeographical realm, and among climatic zone. The structural equation modeling (SEM) showed that the effects of ecosystem, continent, biogeographical realm, and climatic zone were mainly indirect on AMF distribution, but plant had strongly direct effects on AMF. The distribution of AMF as indicated by ITS rDNA sequences showed a pattern of high endemism at large scales. This pattern indicates high specificity of AMF for host at different scales (plant taxonomic

  16. Leishmania in the Old World: 1. The geographical and hostal distribution of L. major zymodemes.

    Science.gov (United States)

    Le Blancq, S M; Schnur, L F; Peters, W

    1986-01-01

    135 stocks of Leishmania major from man, reservoir hosts and sandflies were characterized using thin-layer starch-gel electrophoresis of 13 enzymes: MDH, 6PGD, GD, SOD, ASAT, ALAT, PK, PGM, ES, NH, PEPD, MPI, GPI. Homogeneity in this species was demonstrated by identical electrophoretic mobilities in nine enzymes. Polymorphism in four enzymes: 6PGD, GPI, PEPD, ES, gave six zymodemes among the collection. Stocks from sandflies and several species of burrowing rodents were indistinguishable from those from man in the same areas. Stocks of Leishmania from North-West India were identified as L. major. In some foci the distribution of zymodemes has some correlation with the presence of particular rodent reservoir hosts. The enzymic homogeneity of L. major throughout its geographical and host range appears to be correlated with the close association between L. major and sandflies of the subgenus Phlebotomus. The status of L. major as a distinct species is supported.

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

    Science.gov (United States)

    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

  18. Geographic distribution of wild potato species

    NARCIS (Netherlands)

    Hijmans, R.J.; Spooner, D.M.

    2001-01-01

    The geographic distribution of wild potatoes (Solanaceae sect. Petota) was analyzed using a database of 6073 georeferenced observations. Wild potatoes occur in 16 countries, but 88% of the observations are from Argentina, Bolivia, Mexico, and Peru. Most species are rare and narrowly endemic: for 77

  19. The effects of host, geographic origin, and gender on the thermal requirements of Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Nava, Dori E; Gomez-Torres, Mariuxi L; Rodrigues, Marjorie D; Bento, José M S; Haddad, Marinéia L; Parra, José R P

    2010-04-01

    Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is the vector of the bacteria that causes citrus greening and is considered one of the world's most important citrus diseases. We examined how host, geographic region, and gender affect the thermal requirements of D. citri. The insects were reared in climatic chambers at constant temperatures of 18, 20, 22, 25, 28, 30, and 32 +/- 1 degrees C, 70 +/- 10% RH, and a 14 h photophase. Host plants for D. citri included orange (Citrus sinensis [Rutaceae]) varieties Pêra and Natal, the rootstock, Rungpur lime (C. limonia [Rutaceae]) and the natural host, Orange jessamine (Murraya paniculata [Rutaceae]). To study the influence of geographic origin on thermal requirements, we studied D. citri populations from Piracicaba, SP (warmer region) and Itapetininga, SP (cooler region). The duration and survival of the development stages and the duration of the total development (egg-adult) did not differ significantly on the different hosts, but it did vary with temperature. Nymphs of D. citri created on the different hosts have the same thermal requirements. The thermal requirements for this species collected from the two climate regions were identical; males and females also had the same thermal requirements.

  20. Geographic distribution of canine heartworm (Dirofilaria immitis infection in stray dogs of eastern Romania

    Directory of Open Access Journals (Sweden)

    Lavinia Ciucă

    2016-11-01

    Full Text Available A survey was conducted in the eastern part of Romania to assess the prevalence and geographical distribution of Dirofilaria immitis in dogs. Plasma samples were collected from 458 stray dogs hosted in shelters in 8 counties and tested serologically for the presence of heartworm. In addition, 45 blood samples from dogs of a shelter in Galati city were examined by the modified Knott and multiplex polymerase chain reaction (PCR techniques. The immmunological assay showed a heartworm infection prevalence of 8.9% in the dogs. Optical density results for positive samples ranged between 0.217 and 2.683. Geographical information systems (GIS were used to produce overlays of distribution maps of D. immitis prevalence and predictive maps based on temperature suitability. High prevalence of D. immitis was found in the central East up to the northern border of the country, i.e. Galati county (60%, followed by the counties of Vaslui (12.0% and Iasi (7.7%. Out of 45 samples examined using the Knott test, 23 were positive for circulating microfilariae (51.1%, while 19 dogs were positive for D. immitis and 4 for both D. immitis and D. repens with the multiplex PCR test. The high prevalence for D. immitis shown in dogs in the Southeast (Galati, 42.2% also by multiplex PCR gave strong support to the results achieved by the serological tests. The present study confirms the ability of GIS to predict the distribution and epidemiology of dirofilariosis in different geographical territories as has been already demonstrated by the empirical epidemiological data obtained at the continental, national and intraregional levels.

  1. Leptopsylla algira costai (Siphonaptera: Leptopsyllidae: New host and new geographical record

    Directory of Open Access Journals (Sweden)

    Ali Yousefi

    2016-11-01

    Full Text Available Objective: To access the emerging ectoparasites associated with shrews in Hamedan Province of Iran. Methods: We have captured bicoloured white-toothed shrews [Crocidura leucodon (C. leucodon] using the live traps in April 2014. Ectoparasites collected by brushing the skins were removed and preserved in 70% ethanol containing 5% glycerin, and subsequently they were sent to the parasitology laboratory and processed. The fleas isolated from infested specimen were cleared in 10% aqueous potassium hydroxide, dehydrated in ethanol, cleared in xylene, mounted in Canada balsam and identified using reliable keys. Results: In general, eight fleas (one male, seven females were collected from C. leucodon in Hamedan Province, Western Iran. The fleas were identified as Leptopsylla algira costai Smit, 1955. Conclusions: Fleas are medically important because they transmit a wide variety of diseases to their hosts. In addition, this aricle reports Leptopsylla algira costai for the first time in new host (C. leucodon and new geographical region (Iran.

  2. Identification of geographically distributed sub-populations of Leishmania (Leishmania major by microsatellite analysis

    Directory of Open Access Journals (Sweden)

    Schwenkenbecher Jan

    2008-06-01

    Full Text Available Abstract Background Leishmania (Leishmania major, one of the agents causing cutaneous leishmaniasis (CL in humans, is widely distributed in the Old World where different species of wild rodent and phlebotomine sand fly serve as animal reservoir hosts and vectors, respectively. Despite this, strains of L. (L. major isolated from many different sources over many years have proved to be relatively uniform. To investigate the population structure of the species highly polymorphic microsatellite markers were employed for greater discrimination among it's otherwise closely related strains, an approach applied successfully to other species of Leishmania. Results Multilocus Microsatellite Typing (MLMT based on 10 different microsatellite markers was applied to 106 strains of L. (L. major from different regions where it is endemic. On applying a Bayesian model-based approach, three main populations were identified, corresponding to three separate geographical regions: Central Asia (CA; the Middle East (ME; and Africa (AF. This was congruent with phylogenetic reconstructions based on genetic distances. Re-analysis separated each of the populations into two sub-populations. The two African sub-populations did not correlate well with strains' geographical origin. Strains falling into the sub-populations CA and ME did mostly group according to their place of isolation although some anomalies were seen, probably, owing to human migration. Conclusion The model- and distance-based analyses of the microsatellite data exposed three main populations of L. (L. major, Central Asia, the Middle East and Africa, each of which separated into two sub-populations. This probably correlates with the different species of rodent host.

  3. Veterans Affairs Geographic Distribution of Expenditures FY09 by Congressional District

    Data.gov (United States)

    Department of Veterans Affairs — The Geographic Distribution of VA Expenditures (GDX) is an annual report that shows estimated VA expenditures for major programmatic areas by geographic area (state,...

  4. Veterans Affairs Geographic Distribution of Expenditures FY08 by Congressional District

    Data.gov (United States)

    Department of Veterans Affairs — The Geographic Distribution of VA Expenditures (GDX) is an annual report that shows estimated VA expenditures for major programmatic areas by geographic area (state,...

  5. Discordant genetic diversity and geographic patterns between Crassicutis cichlasomae (Digenea: Apocreadiidae) and its cichlid host, "Cichlasoma" urophthalmus (Osteichthyes: Cichlidae), in Middle-America.

    Science.gov (United States)

    Razo-Mendivil, Ulises; Vázquez-Domínguez, Ella; de León, Gerardo Pérez-Ponce

    2013-12-01

    Genetic analyses of hosts and their parasites are key to understand the evolutionary patterns and processes that have shaped host-parasite associations. We evaluated the genetic structure of the digenean Crassicutis cichlasomae and its most common host, the Mayan cichlid "Cichlasoma" urophthalmus, encompassing most of their geographical range in Middle-America (river basins in southeastern Mexico, Belize, and Guatemala together with the Yucatan Peninsula). Genetic diversity and structure analyses were done based on 167 cytochrome c oxidase subunit 1 sequences (330 bp) for C. cichlasomae from 21 populations and 161 cytochrome b sequences (599 bp) for "C." urophthalmus from 26 populations. Analyses performed included phylogenetic tree estimation under Bayesian inference and maximum likelihood analysis, genetic diversity, distance and structure estimates, haplotype networks, and demographic evaluations. Crassicutis cichlasomae showed high genetic diversity values and genetic structuring, corresponding with 4 groups clearly differentiated and highly divergent. Conversely, "C." urophthalmus showed low levels of genetic diversity and genetic differentiation, defined as 2 groups with low divergence and with no correspondence with geographical distribution. Our results show that species of cichlids parasitized by C. cichlasomae other than "C." urophthalmus, along with multiple colonization events and subsequent isolation in different basins, are likely factors that shaped the genetic structure of the parasite. Meanwhile, historical long-distance dispersal and drought periods during the Holocene, with significant population size reductions and fragmentations, are factors that could have shaped the genetic structure of the Mayan cichlid.

  6. Host specialization and phylogenetic diversity of Corynespora cassiicola.

    Science.gov (United States)

    Dixon, L J; Schlub, R L; Pernezny, K; Datnoff, L E

    2009-09-01

    The fungus Corynespora cassiicola is primarily found in the tropics and subtropics, and is widely diverse in substrate utilization and host association. Isolate characterization within C. cassiicola was undertaken to investigate how genetic diversity correlates with host specificity, growth rate, and geographic distribution. C. cassiicola isolates were collected from 68 different plant species in American Samoa, Brazil, Malaysia, and Micronesia, and Florida, Mississippi, and Tennessee within the United States. Phylogenetic analyses using four loci were performed with 143 Corynespora spp. isolates, including outgroup taxa obtained from culture collections: C. citricola, C. melongenae, C. olivacea, C. proliferata, C. sesamum, and C. smithii. Phylogenetic trees were congruent from the ribosomal DNA internal transcribed spacer region, two random hypervariable loci (caa5 and ga4), and the actin-encoding locus act1, indicating a lack of recombination within the species and asexual propagation. Fifty isolates were tested for pathogenicity on eight known C. cassiicola crop hosts: basil, bean, cowpea, cucumber, papaya, soybean, sweet potato, and tomato. Pathogenicity profiles ranged from one to four hosts, with cucumber appearing in 14 of the 16 profiles. Bootstrap analyses and Bayesian posterior probability values identified six statistically significant phylogenetic lineages. The six phylogenetic lineages correlated with host of origin, pathogenicity, and growth rate but not with geographic location. Common fungal genotypes were widely distributed geographically, indicating long-distance and global dispersal of clonal lineages. This research reveals an abundance of previously unrecognized genetic diversity within the species and provides evidence for host specialization on papaya.

  7. Measuring Geographic Distribution of Economic Activity in Nigeria ...

    African Journals Online (AJOL)

    Measuring Geographic Distribution of Economic Activity in Nigeria Using Gross Domestic Product. ... and environmental factors in planning. There is need for adequate understanding of spatial pattern and centrographic analysis of economic activity to support evidence based economic and regional development policies.

  8. Identification, Geographical Distribution and Hosts of Subterranean Termites in the United Arab Emirates Arid Ecosystem

    Directory of Open Access Journals (Sweden)

    W. Kaakeh

    2005-01-01

    Full Text Available Six termite species, belonging to five genera and three families (Hodotermitidae, Rhinotermitidae and Termitidae were identified in the United Arab Emirates (UAE. Termite species recorded were the harvester termites Anacanthotermes ochraceus (Burmeister and Anacanthotermes ubachi (Navas, the sand termite Psammotermes hypostoma (Desneux and the small waxy termites Microcerotermes diversus (Silvestri, Heterotermes aethiopicus (Sjostedt, and Microtermes najdensis (Harris. Except for a previous record of H. aethiopicus, the other five species were recorded for the first time in the UAE. All species were subterranean in habitat and reach wood sources through earthen gallery systems. Termites were available in areas with varied conditions of climate, vegetation and soil types. Termites showed host preference for dead, living, or decaying plant materials and non-cellulose materials. The dominant termite species recorded was A. ochraceus, followed by P. hypostoma and M. diversus. The distributions of the six termite species varied in each of the seven Emirates. All species were present in the two largest Emirates of Abu Dhabi and Dubai.

  9. Capacity of Distribution Feeders for Hosting Distributed Energy Resources

    DEFF Research Database (Denmark)

    Papathanassiou, S.; Hatziargyriou, N.; Anagnostopoulos, P.

    The last two decades have seen an unprecedented development of distributed energy resources (DER) all over the world. Several countries have adopted a variety of support schemes (feed-in tariffs, green certificates, direct subsidies, tax exemptions etc.) so as to promote distributed generation (DG...... standards of the networks. To address this need in a timely and effective manner, simplified methodologies and practical rules of thumbs are often applied to assess the DER hosting capacity of existing distribution networks, avoiding thus detailed and time consuming analytical studies. The scope...

  10. Veterans Affairs Geographic Distribution of Expenditures FY07 by State and County

    Data.gov (United States)

    Department of Veterans Affairs — The Geographic Distribution of VA Expenditures (GDX) is an annual report that shows estimated VA expenditures for major programmatic areas by geographic area (state,...

  11. Veterans Affairs Geographic Distribution of Expenditures FY08 by State and County

    Data.gov (United States)

    Department of Veterans Affairs — The Geographic Distribution of VA Expenditures (GDX) is an annual report that shows estimated VA expenditures for major programmatic areas by geographic area (state,...

  12. Combining Phylogenetic and Occurrence Information for Risk Assessment of Pest and Pathogen Interactions with Host Plants

    Directory of Open Access Journals (Sweden)

    Ángel L. Robles-Fernández

    2017-08-01

    Full Text Available Phytosanitary agencies conduct plant biosecurity activities, including early detection of potential introduction pathways, to improve control and eradication of pest and pathogen incursions. For such actions, analytical tools based on solid scientific knowledge regarding plant-pest or pathogen relationships for pest risk assessment are needed. Recent evidence indicating that closely related species share a higher chance of becoming infected or attacked by pests has allowed the identification of taxa with different degrees of vulnerability. Here, we use information readily available online about pest-host interactions and their geographic distributions, in combination with host phylogenetic reconstructions, to estimate a pest-host interaction (in some cases infection index in geographic space as a more comprehensive, spatially explicit tool for risk assessment. We demonstrate this protocol using phylogenetic relationships for 20 beetle species and 235 host plant genera: first, we estimate the probability of a host sharing pests, and second, we project the index in geographic space. Overall, the predictions allow identification of the pest-host interaction type (e.g., generalist or specialist, which is largely determined by both host range and phylogenetic constraints. Furthermore, the results can be valuable in terms of identifying hotspots where pests and vulnerable hosts interact. This knowledge is useful for anticipating biological invasions or spreading of disease. We suggest that our understanding of biotic interactions will improve after combining information from multiple dimensions of biodiversity at multiple scales (e.g., phylogenetic signal and host-vector-pathogen geographic distribution.

  13. Geographic distribution of hospital beds throughout China: a county-level econometric analysis.

    Science.gov (United States)

    Pan, Jay; Shallcross, David

    2016-11-08

    Geographical distribution of healthcare resources is an important dimension of healthcare access. Little work has been published on healthcare resource allocation patterns in China, despite public equity concerns. Using national data from 2043 counties, this paper investigates the geographic distribution of hospital beds at the county level in China. We performed Gini coefficient analysis to measure inequalities and ordinary least squares regression with fixed provincial effects and additional spatial specifications to assess key determinants. We found that provinces in west China have the least equitable resource distribution. We also found that the distribution of hospital beds is highly spatially clustered. Finally, we found that both county-level savings and government revenue show a strong positive relationship with county level hospital bed density. We argue for more widespread use of disaggregated, geographical data in health policy-making in China to support the rational allocation of healthcare resources, thus promoting efficiency and equity.

  14. Modelling the geographic distribution of wind power and the impact on transmission needs

    DEFF Research Database (Denmark)

    Østergaard, Poul Alberg

    2003-01-01

    Through energy systems modelling, transmission systems modelling and geographical modelling, the article examines the sensitivity of the response of the transmission system to the geographic distributions of wind power and in particular the sensitivity of the results to the accuracy...... of the distributed modelled. The results show that accuracy of the geographic modelling while important for the analysis of specific single transmission lines is not important for the analysis of the general response of the transmission system. The analyses thus corroborate previous analyses that demonstrated...

  15. Interactive analysis of geographically distributed population imaging data collections over light-path data networks

    Science.gov (United States)

    van Lew, Baldur; Botha, Charl P.; Milles, Julien R.; Vrooman, Henri A.; van de Giessen, Martijn; Lelieveldt, Boudewijn P. F.

    2015-03-01

    The cohort size required in epidemiological imaging genetics studies often mandates the pooling of data from multiple hospitals. Patient data, however, is subject to strict privacy protection regimes, and physical data storage may be legally restricted to a hospital network. To enable biomarker discovery, fast data access and interactive data exploration must be combined with high-performance computing resources, while respecting privacy regulations. We present a system using fast and inherently secure light-paths to access distributed data, thereby obviating the need for a central data repository. A secure private cloud computing framework facilitates interactive, computationally intensive exploration of this geographically distributed, privacy sensitive data. As a proof of concept, MRI brain imaging data hosted at two remote sites were processed in response to a user command at a third site. The system was able to automatically start virtual machines, run a selected processing pipeline and write results to a user accessible database, while keeping data locally stored in the hospitals. Individual tasks took approximately 50% longer compared to a locally hosted blade server but the cloud infrastructure reduced the total elapsed time by a factor of 40 using 70 virtual machines in the cloud. We demonstrated that the combination light-path and private cloud is a viable means of building an analysis infrastructure for secure data analysis. The system requires further work in the areas of error handling, load balancing and secure support of multiple users.

  16. Limited geographic distribution of the novel cyclovirus CyCV-VN.

    Science.gov (United States)

    Le, Van Tan; de Jong, Menno D; Nguyen, Van Kinh; Nguyen, Vu Trung; Taylor, Walter; Wertheim, Heiman F L; van der Ende, Arie; van der Hoek, Lia; Canuti, Marta; Crusat, Martin; Sona, Soeng; Nguyen, Hanh Uyen; Giri, Abhishek; Nguyen, Thi Thuy Chinh Bkrong; Ho, Dang Trung Nghia; Farrar, Jeremy; Bryant, Juliet E; Tran, Tinh Hien; Nguyen, Van Vinh Chau; van Doorn, H Rogier

    2014-02-05

    A novel cyclovirus, CyCV-VN, was recently identified in cerebrospinal fluid (CSF) from patients with central nervous system (CNS) infections in central and southern Vietnam. To explore the geographic distribution of this novel virus, more than 600 CSF specimens from patients with suspected CNS infections in northern Vietnam, Cambodia, Nepal and The Netherlands were screened for the presence of CyCV-VN but all were negative. Sequence comparison and phylogenetic analysis between CyCV-VN and another novel cyclovirus recently identified in CSF from Malawian patients indicated that these represent distinct cycloviral species, albeit phylogenetically closely related. The data suggest that CyCV-VN has a limited geographic distribution within southern and central Vietnam. Further research is needed to determine the global distribution and diversity of cycloviruses and importantly their possible association with human disease.

  17. Spatially-explicit estimation of geographical representation in large-scale species distribution datasets.

    Science.gov (United States)

    Kalwij, Jesse M; Robertson, Mark P; Ronk, Argo; Zobel, Martin; Pärtel, Meelis

    2014-01-01

    Much ecological research relies on existing multispecies distribution datasets. Such datasets, however, can vary considerably in quality, extent, resolution or taxonomic coverage. We provide a framework for a spatially-explicit evaluation of geographical representation within large-scale species distribution datasets, using the comparison of an occurrence atlas with a range atlas dataset as a working example. Specifically, we compared occurrence maps for 3773 taxa from the widely-used Atlas Florae Europaeae (AFE) with digitised range maps for 2049 taxa of the lesser-known Atlas of North European Vascular Plants. We calculated the level of agreement at a 50-km spatial resolution using average latitudinal and longitudinal species range, and area of occupancy. Agreement in species distribution was calculated and mapped using Jaccard similarity index and a reduced major axis (RMA) regression analysis of species richness between the entire atlases (5221 taxa in total) and between co-occurring species (601 taxa). We found no difference in distribution ranges or in the area of occupancy frequency distribution, indicating that atlases were sufficiently overlapping for a valid comparison. The similarity index map showed high levels of agreement for central, western, and northern Europe. The RMA regression confirmed that geographical representation of AFE was low in areas with a sparse data recording history (e.g., Russia, Belarus and the Ukraine). For co-occurring species in south-eastern Europe, however, the Atlas of North European Vascular Plants showed remarkably higher richness estimations. Geographical representation of atlas data can be much more heterogeneous than often assumed. Level of agreement between datasets can be used to evaluate geographical representation within datasets. Merging atlases into a single dataset is worthwhile in spite of methodological differences, and helps to fill gaps in our knowledge of species distribution ranges. Species distribution

  18. Application of a random walk model to geographic distributions of animal mitochondrial DNA variation.

    Science.gov (United States)

    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.

  19. Estimating Hantavirus Risk in Southern Argentina: A GIS-Based Approach Combining Human Cases and Host Distribution

    Directory of Open Access Journals (Sweden)

    Veronica Andreo

    2014-01-01

    Full Text Available We use a Species Distribution Modeling (SDM approach along with Geographic Information Systems (GIS techniques to examine the potential distribution of hantavirus pulmonary syndrome (HPS caused by Andes virus (ANDV in southern Argentina and, more precisely, define and estimate the area with the highest infection probability for humans, through the combination with the distribution map for the competent rodent host (Oligoryzomys longicaudatus. Sites with confirmed cases of HPS in the period 1995–2009 were mostly concentrated in a narrow strip (~90 km × 900 km along the Andes range from northern Neuquén to central Chubut province. This area is characterized by high mean annual precipitation (~1,000 mm on average, but dry summers (less than 100 mm, very low percentages of bare soil (~10% on average and low temperatures in the coldest month (minimum average temperature −1.5 °C, as compared to the HPS-free areas, features that coincide with sub-Antarctic forests and shrublands (especially those dominated by the invasive plant Rosa rubiginosa, where rodent host abundances and ANDV prevalences are known to be the highest. Through the combination of predictive distribution maps of the reservoir host and disease cases, we found that the area with the highest probability for HPS to occur overlaps only 28% with the most suitable habitat for O. longicaudatus. With this approach, we made a step forward in the understanding of the risk factors that need to be considered in the forecasting and mapping of risk at the regional/national scale. We propose the implementation and use of thematic maps, such as the one built here, as a basic tool allowing public health authorities to focus surveillance efforts and normally scarce resources for prevention and control actions in vast areas like southern Argentina.

  20. Estimating Hantavirus Risk in Southern Argentina: A GIS-Based Approach Combining Human Cases and Host Distribution

    Science.gov (United States)

    Andreo, Veronica; Neteler, Markus; Rocchini, Duccio; Provensal, Cecilia; Levis, Silvana; Porcasi, Ximena; Rizzoli, Annapaola; Lanfri, Mario; Scavuzzo, Marcelo; Pini, Noemi; Enria, Delia; Polop, Jaime

    2014-01-01

    We use a Species Distribution Modeling (SDM) approach along with Geographic Information Systems (GIS) techniques to examine the potential distribution of hantavirus pulmonary syndrome (HPS) caused by Andes virus (ANDV) in southern Argentina and, more precisely, define and estimate the area with the highest infection probability for humans, through the combination with the distribution map for the competent rodent host (Oligoryzomys longicaudatus). Sites with confirmed cases of HPS in the period 1995–2009 were mostly concentrated in a narrow strip (~90 km × 900 km) along the Andes range from northern Neuquén to central Chubut province. This area is characterized by high mean annual precipitation (~1,000 mm on average), but dry summers (less than 100 mm), very low percentages of bare soil (~10% on average) and low temperatures in the coldest month (minimum average temperature −1.5 °C), as compared to the HPS-free areas, features that coincide with sub-Antarctic forests and shrublands (especially those dominated by the invasive plant Rosa rubiginosa), where rodent host abundances and ANDV prevalences are known to be the highest. Through the combination of predictive distribution maps of the reservoir host and disease cases, we found that the area with the highest probability for HPS to occur overlaps only 28% with the most suitable habitat for O. longicaudatus. With this approach, we made a step forward in the understanding of the risk factors that need to be considered in the forecasting and mapping of risk at the regional/national scale. We propose the implementation and use of thematic maps, such as the one built here, as a basic tool allowing public health authorities to focus surveillance efforts and normally scarce resources for prevention and control actions in vast areas like southern Argentina. PMID:24424500

  1. Mapping host-species abundance of three major exotic forest pests

    Science.gov (United States)

    Randall S. Morin; Andrew M. Liebhold; Eugene R. Luzader; Andrew J. Lister; Kurt W. Gottschalk; Daniel B. Twardus

    2005-01-01

    Periodically over the last century, forests of the Eastern United States devastated by invasive pests. We used existing data to predict the geographical extent of future damage from beech bark disease (BBD), hemlock woolly adelgid (HWA), and gypsy moth. The distributions of host species of these alien pests were mapped in 1-km2 cells by interpolating host basal area/ha...

  2. Formation and distribution of international tourism flows in geographical space

    Directory of Open Access Journals (Sweden)

    Oleksandr Korol

    2017-10-01

    Full Text Available Properties of geographical space that are of key importance for international tourism, as length and discreteness, are analyzed in the article. Length makes tourists cover distances, whereas discreteness manifests itself in spatial heterogeneity. Tourism in conditions of homogeneous space is vain. That is, heterogeneity brings sense to travels as well as determines their direction. So, the effect of geographical space’s length and spatial heterogeneity on formation and distribution of tourism flows is assessed, international tourism’s geographical essence is disclosed also. Apperception of geographical space in usual environment and its effect on tourist’s original motives are described. Following the bases of behaviorism, the tourism original motives, in particular those for migration, comfort, contrast and aesthetics are substantiated. The motive for migration is a kind of “pushing” tourists outside their usual environment. To stop all fears that may cause anxiety in destination, the latter should guarantee satisfaction of those human needs which A. Maslow refers to as basic needs. The necessity to satisfy these needs forms in tourists the motive for comfort. Closely located destinations in neighboring countries can be of little difference form usual environment. Driven by the motive for contrast, tourists aspire to visit places that totally differ from their usual environment, and contrast (are exotic to it. Thus, the motive for contrast seemingly “pulls” the tourists up to certain (exotic destinations. Finally, following the considered spatial specificities of land surface and tourist-driving original motives, a conceptual model of formation and distribution of international tourism flows in geographical space is developed.

  3. [Geographic distribution of avoidable mortality in the community of Valencia (1975-1990)].

    Science.gov (United States)

    Ros, X A; Bayo Vila, A; Alfonso Sánchez, J L; Cortina Greus, P; Chana González, P; Sáiz Sánchez, C

    1996-04-20

    Avoidable mortality (AM) has been proposed as the indicator of the quality and the efficacy of health care services and a parameter useful to distribute health care resources. The aim of this study was to analyze the size and geographic variability of AM in the Community of Valencia, Spain (1975-1990). The causes of AM were analyzed by the classification of Holland divided into indicators of medical care (IMC) and indicators on national health care policy (INHCP) in addition to the causes of the Charlton classification. Standard rates for Spain and the European Community, the rate of masculinity and contribution to total mortality were calculated. Geographic distribution by areas and provinces was analyzed by the rate of standardized mortality. According to the Holland classification AM was 30% of the deaths from 5 to 64 years of age. Out of these cases, 18.5% corresponded to INHCP and 11.1% to IMC. According to the Charlton classification, this percentage was 3.6%. A considerable variation was observed among the 20 areas analyzed due to many causes. The geographic distribution by groups (IMC, INHCP and the Charlton classification) is quite homogeneous. The worse results corresponded to the city of Valencia and to the area 21 (area of the city of Alicante). A great variation was found in the results regarding geographic distribution for individual causes of death while the distribution was quite homogeneous for all of the groups of mortality with the worst results being observed in large urban centers.

  4. Reptiles of Chubut province, Argentina: richness, diversity, conservation status and geographic distribution maps

    Science.gov (United States)

    Minoli, Ignacio; Morando, Mariana; Avila, Luciano Javier

    2015-01-01

    Abstract An accurate estimation of species and population geographic ranges is essential for species-focused studies and conservation and management plans. Knowledge of the geographic distributions of reptiles from Patagonian Argentina is in general limited and dispersed over manuscripts from a wide variety of topics. We completed an extensive review of reptile species of central Patagonia (Argentina) based on information from a wide variety of sources. We compiled and checked geographic distribution records from published literature and museum records, including extensive new data from the LJAMM-CNP (CENPAT-CONICET) herpetological collection. Our results show that there are 52 taxa recorded for this region and the highest species richness was seen in the families Liolaemidae and Dipsadidae with 31 and 10 species, respectively. The Patagónica was the phytogeographic province most diverse in species and Phymaturus was the genus of conservation concern most strongly associated with it. We present a detailed species list with geographical information, richness species, diversity analyses with comparisons across phytogeographical provinces, conservation status, taxonomic comments and distribution maps for all of these taxa. PMID:25931966

  5. Epidemiology and geographical distribution of enteric protozoan infections in Sydney, Australia

    Directory of Open Access Journals (Sweden)

    Stephanie Fletcher

    2014-07-01

    Full Text Available Background. Enteric protozoa are associated with diarrhoeal illnesses in humans; however there are no recent studies on their epidemiology and geographical distribution in Australia. This study describes the epidemiology of enteric protozoa in the state of New South Wales and incorporates spatial analysis to describe their distribution. Design and methods. Laboratory and clinical records from four public hospitals in Sydney for 910 patients, who tested positive for enteric protozoa over the period January 2007-December 2010, were identified, examined and analysed. We selected 580 cases which had residence post code data available, enabling us to examine the geographic distribution of patients, and reviewed the clinical data of 252 patients to examine possible links between protozoa, demographic and clinical features. Results. Frequently detected protozoa were Blastocystis spp. (57%, Giardia intestinalis (27% and Dientamoeba fragilis (12%. The age distribution showed that the prevalence of protozoa decreased with age up to 24 years but increasing with age from 25 years onwards. The geographic provenance of the patients indicates that the majority of cases of Blastocystis (53.1% are clustered in and around the Sydney City Business District, while pockets of giardiasis were identified in regional/rural areas. The distribution of cases suggests higher risk of protozoan infection may exist for some communities. Conclusions. These findings provide useful information for policy makers to design and tailor interventions to target high risk communities. Follow-up investigation into the risk factors for giardiasis in regional/rural area is needed.

  6. Distribution and habitats of Lymnaea natalensis, snail intermediate host of the liver fluke Fasciola gigantica, in South Africa

    Directory of Open Access Journals (Sweden)

    Editorial Office

    2001-09-01

    Full Text Available This paper focuses on the geographical distribution and the habitats of Lymnaea natalensis, the snail intermediate host of the liver fluke, Fasciola gigantica, as reflected by the collection sites of its 4 552 samples currently on record in the National Freshwater Snail Collection (NFSC of South Africa. Although this species was represented in a variety of waterbodies, the majority of samples(±70%came from rivers, brooks and dams and in 70.8% of the cases the water was described as permanent and in 71.8% as slow flowing or standing. The results of life-table studies conducted by various authors indicated that temperature should be a relatively unimportant factor in determining its geographical distribution, but that the availability of permanent water should be decisive for its presence in a given habitat. These results are in agreement with the finding that only 7.5% of the samples of this species in the NFSC were collected in habitats which were described as seasonal. Furthermore, it gives a logical explanation for the sporadic occurrence, or total absence of this species in the more arid regions of South Africa. Water impoundments and irrigation networks contribute to a large extent towards creating perennial habitats which would be suitable for L. natalensis. As intermediate host for one of the liver fluke species which already is an economic factor in South Africa, this certainly is an aspect which ought to be reckoned within the planning and construction of new irrigation schemes.

  7. [Geographic distribution of supportive care for disabled young people].

    Science.gov (United States)

    Bourgarel, Sophie; Piteau-Delord, Monique

    2013-01-01

    To analyse the logic for the distribution of home care services for disabled children (SESSAD) in a context of under-equipment. Questionnaire-based survey of 75 units (82% of the region's SESSAD units) concerning patient transport. Equipment and transport mapping. Support units for disabled children are often set up in the housing facilities that contributed to their creation. These sites are sometimes situated a long way from densely populated regions, thereby generating unnecessary travel times and expenses. Chronic under-equipment makes these sites viable, as the various units are always full, despite their distance from the children for whom they provide support. Mapping illustrates the extensive recruitment zones overlapping several units managing similar patients. The major revision of accreditation of these units, planned for 2017, could lead to redefinition of geographical zones of accreditations. New unit opening procedures based on ARS calls for tenders may help to improve the geographical distribution of this supportive care.

  8. From the Atlantic Forest to the borders of Amazonia: species richness, distribution, and host association of ectoparasitic flies (Diptera: Nycteribiidae and Streblidae) in northeastern Brazil.

    Science.gov (United States)

    Barbier, Eder; Bernard, Enrico

    2017-11-01

    Better knowledge of the geographical distribution of parasites and their hosts can contribute to clarifying aspects of host specificity, as well as on the interactions among hosts, parasites, and the environment in which both exist. Ectoparasitic flies of the Nycteribiidae and Streblidae families are highly specialized hematophagous parasites of bats, whose distributional patterns, species richness, and associations with hosts remain underexplored and poorly known in Brazil. Here, we used information available in the literature and unpublished data to verify if the occurrence of bat hosts in a given environment influences the occurrence and distribution of nycteribiid and streblid flies in different ecoregions in the northeastern Brazil. We evaluate species richness and similarity between ecoregions and tested correlations between species richness and the number of studies in each ecoregion and federative unit. We recorded 50 species and 15 genera of bat ectoparasitic flies on 36 species and 27 genera of bat hosts. The Atlantic Forest had the highest fly species richness (n = 31; 62%), followed by Caatinga (n = 27; 54%). We detected the formation of distinct groups, with low species overlap between ecoregions for both flies and bats. Fly species richness was correlated with host species richness and with the number of studies in each federative unit, but not with the number of studies by ecoregion. Due to the formation of distinct groups with low species overlap for both groups, host availability is likely to be one of the factors that most influence the occurrence of highly specific flies. We also discuss host specificity for some species, produced an updated list of species and distribution for both nycteribiid and streblid flies with information on interaction networks, and conclude by presenting recommendations for more effective inventories of bat ectoparasites in the future.

  9. FEATURES OF THE GEOGRAPHICAL DISTRIBUTION OF TERRESTRIAL MOLLUSCS IN THE CAUCASUS

    Directory of Open Access Journals (Sweden)

    M. Z. Magomedova

    2015-01-01

    Full Text Available Aim. High population, high proliferation rates, a large species diversity, low mobility and small ability to overcome geographic barriers, ease of collecting material and sensitive response to changes in the external environment makes this group a convenient object of biogeographic and ecological research. Methods. The inventory of Caucasian ground malacofauna made it possible to make a complete list of species; their characteristics were determined by the geographical distribution of major natural regions of the Caucasus. Results. The comparative analysis of the geographical distribution of terrestrial molluscs on key areas of the Caucasus showed that among the 352 species belonging to 140 genera of 36 families, most richly represented Western Caucasus, which accounts for 51% or 181 species from 80 genera of 20 families, while the share of Armenian, Eastern and Central Caucasus accounts for 35-37%. Talysh, in turn, is characterized by the presence of only 11% of the species composition of the Caucasian land mollusc. Caucasus limited in distribution among the analyzed species is 72% or 255 species belonging to 104 genera of 24 families. Conclusion. The results prove the species diversity of the different regions of theCaucasus and could serve as the basis to reconsider the possible ways of formation of fauna of the region discussed. 

  10. Modelling grid losses and the geographic distribution of electricity generation

    DEFF Research Database (Denmark)

    Østergaard, Poul Alberg

    2005-01-01

    In Denmark more than 40% of the electricity consumption is covered by geographically scattered electricity sources namely wind power and local CHP (cogeneration of heat and power) plants. This causes problems in regard to load balancing and possible grid overloads. The potential grid problems...... and methods for solving these are analysed in this article on the basis of energy systems analyses, geographic distribution of consumption and production and grid load-flow analyses. It is concluded that by introducing scattered load balancing using local CHP plants actively and using interruptible loads...

  11. Bat distribution size or shape as determinant of viral richness in african bats.

    Directory of Open Access Journals (Sweden)

    Gaël D Maganga

    Full Text Available The rising incidence of emerging infectious diseases (EID is mostly linked to biodiversity loss, changes in habitat use and increasing habitat fragmentation. Bats are linked to a growing number of EID but few studies have explored the factors of viral richness in bats. These may have implications for role of bats as potential reservoirs. We investigated the determinants of viral richness in 15 species of African bats (8 Pteropodidae and 7 microchiroptera in Central and West Africa for which we provide new information on virus infection and bat phylogeny. We performed the first comparative analysis testing the correlation of the fragmented geographical distribution (defined as the perimeter to area ratio with viral richness in bats. Because of their potential effect, sampling effort, host body weight, ecological and behavioural traits such as roosting behaviour, migration and geographical range, were included into the analysis as variables. The results showed that the geographical distribution size, shape and host body weight have significant effects on viral richness in bats. Viral richness was higher in large-bodied bats which had larger and more fragmented distribution areas. Accumulation of viruses may be related to the historical expansion and contraction of bat species distribution range, with potentially strong effects of distribution edges on virus transmission. Two potential explanations may explain these results. A positive distribution edge effect on the abundance or distribution of some bat species could have facilitated host switches. Alternatively, parasitism could play a direct role in shaping the distribution range of hosts through host local extinction by virulent parasites. This study highlights the importance of considering the fragmentation of bat species geographical distribution in order to understand their role in the circulation of viruses in Africa.

  12. [Projection of potential geographic distribution of Apocynum venetum under climate change in northern China].

    Science.gov (United States)

    Yang, Hui-Feng; Zheng, Jiang-Hua; Jia, Xiao-Guang; Li, Xiao-Jin

    2017-03-01

    Apocynum venetum belongs to apocynaceae and is a perennial medicinal plant, its stem is an important textile raw materials. The projection of potential geographic distribution of A. venetum has an important significance for the protection and sustainable utilization of the plant. This study was conducted to determine the potential geographic distribution of A. venetum and to project how climate change would affect its geographic distribution. The projection geographic distribution of A. venetum under current bioclimatic conditions in northern China was simulated using MaxEnt software based on species presence data at 44 locations and 19 bioclimatic parameters. The future distributions of A. venetum were also projected in 2050 and 2070 under the climate change scenarios of RCP2.6 and RCP8.5 described in 5th Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). The result showed that min air temperature of the coldest month, annual mean air temperature, precipitation of the coldest quarter and mean air temperature of the wettest quarter dominated the geographic distribution of A. venetum. Under current climate, the suitable habitats of A. venetum is 11.94% in China, the suitable habitats are mainly located in the middle of Xinjiang, in the northern part of Gansu, in the southern part of Neimeng, in the northern part of Ningxia, in the middle and northern part of Shaanxi, in the southern part of Shanxi, in the middle and northern part of Henan, in the middle and southern part of Hebei, Shandong, Tianjin, in the southern part of Liaoning and part of Beijing. From 2050 to 2070, the model outputs indicated that the suitable habitats of A. venetum would decrease under the climate change scenarios of RCP2.6 and RCP8.5. Copyright© by the Chinese Pharmaceutical Association.

  13. Sequence Variation in Toxoplasma gondii rop17 Gene among Strains from Different Hosts and Geographical Locations

    Directory of Open Access Journals (Sweden)

    Nian-Zhang Zhang

    2014-01-01

    Full Text Available Genetic diversity of T. gondii is a concern of many studies, due to the biological and epidemiological diversity of this parasite. The present study examined sequence variation in rhoptry protein 17 (ROP17 gene among T. gondii isolates from different hosts and geographical regions. The rop17 gene was amplified and sequenced from 10 T. gondii strains, and phylogenetic relationship among these T. gondii strains was reconstructed using maximum parsimony (MP, neighbor-joining (NJ, and maximum likelihood (ML analyses. The partial rop17 gene sequences were 1375 bp in length and A+T contents varied from 49.45% to 50.11% among all examined T. gondii strains. Sequence analysis identified 33 variable nucleotide positions (2.1%, 16 of which were identified as transitions. Phylogeny reconstruction based on rop17 gene data revealed two major clusters which could readily distinguish Type I and Type II strains. Analyses of sequence variations in nucleotides and amino acids among these strains revealed high ratio of nonsynonymous to synonymous polymorphisms (>1, indicating that rop17 shows signs of positive selection. This study demonstrated the existence of slightly high sequence variability in the rop17 gene sequences among T. gondii strains from different hosts and geographical regions, suggesting that rop17 gene may represent a new genetic marker for population genetic studies of T. gondii isolates.

  14. Analysis Of Educational Services Distribution-Based Geographic Information System GIS

    Directory of Open Access Journals (Sweden)

    Waleed Lagrab

    2015-03-01

    Full Text Available Abstract This study analyzes the spatial distribution of kindergarten facilities in the study area based on the Geographic Information Systems GIS in order to test an efficiency of GIS technology to redistribute the existing kindergarten and choose the best location in the future and applying the standard criteria for selecting the suitable locations for kindergarten. To achieve this goal the data and information are collected via interviews and comprehensive statistics on the education facilities in Mukalla districts in YEMEN which contributed to building a geographic database for the study area. After that the Kindergarten spatial patterns are analyzed in terms of proximity to each other and used near some other land in the surrounding area such as streets highways factories etc. Also measures the concentration dispersion clustering and distribution direction for the kindergarten this study showed the effectiveness of the GIS for spatial data analysis. One of the most important finding that most of the Kindergarten was established in Mukalla city did not take into account the criteria that set by the authorities. Furthermore almost district suffers from a shortage in the number of kindergarten and pattern of distribution of those kindergartens dominated by spatial dispersed.

  15. Limited geographic distribution of the novel cyclovirus CyCV-VN

    NARCIS (Netherlands)

    Le, Van Tan; de Jong, Menno D.; Nguyen, Van Kinh; Nguyen, Vu Trung; Taylor, Walter; Wertheim, Heiman F. L.; van der Ende, Arie; van der Hoek, Lia; Canuti, Marta; Crusat, Martin; Sona, Soeng; Nguyen, Hanh Uyen; Giri, Abhishek; Nguyen, Thi Thuy Chinh Bkrong; Ho, Dang Trung Nghia; Farrar, Jeremy; Bryant, Juliet E.; Tran, Tinh Hien; Nguyen, Van Vinh Chau; van Doorn, H. Rogier

    2014-01-01

    A novel cyclovirus, CyCV-VN, was recently identified in cerebrospinal fluid (CSF) from patients with central nervous system (CNS) infections in central and southern Vietnam. To explore the geographic distribution of this novel virus, more than 600 CSF specimens from patients with suspected CNS

  16. Predicting geographically distributed adult dental decay in the greater Auckland region of New Zealand.

    Science.gov (United States)

    Rocha, C M; Kruger, E; Whyman, R; Tennant, M

    2014-06-01

    To model the geographic distribution of current (and treated) dental decay on a high-resolution geographic basis for the Auckland region of New Zealand. The application of matrix-based mathematics to modelling adult dental disease-based on known population risk profiles to provide a detailed map of the dental caries distribution for the greater Auckland region. Of the 29 million teeth in adults in the region some 1.2 million (4%) are suffering decay whilst 7.2 million (25%) have previously suffered decay and are now restored. The model provides a high-resolution picture of where the disease burden lies geographically and presents to health planners a method for developing future service plans.

  17. Nematode-associated microbial taxa do not correlate with host phylogeny, geographic region or feeding morphology in marine sediment habitats.

    Science.gov (United States)

    Schuelke, Taruna; Pereira, Tiago José; Hardy, Sarah M; Bik, Holly M

    2018-04-01

    Studies of host-associated microbes are critical for advancing our understanding of ecology and evolution across diverse taxa and ecosystems. Nematode worms are ubiquitous across most habitats on earth, yet little is known about host-associated microbial assemblages within the phylum. Free-living nematodes are globally abundant and diverse in marine sediments, with species exhibiting distinct buccal cavity (mouth) morphologies that are thought to play an important role in feeding ecology and life history strategies. Here, we investigated patterns in marine nematode microbiomes, by characterizing host-associated microbial taxa in 281 worms isolated from a range of habitat types (deep-sea, shallow water, methane seeps, Lophelia coral mounds, kelp holdfasts) across three distinct geographic regions (Arctic, Southern California and Gulf of Mexico). Microbiome profiles were generated from single worms spanning 33 distinct morphological genera, using a two-gene metabarcoding approach to amplify the V4 region of the 16S ribosomal RNA (rRNA) gene targeting bacteria/archaea and the V1-V2 region of the 18S rRNA gene targeting microbial eukaryotes. Contrary to our expectations, nematode microbiome profiles demonstrated no distinct patterns either globally (across depths and ocean basins) or locally (within site); prokaryotic and eukaryotic microbial assemblages did not correlate with nematode feeding morphology, host phylogeny or morphological identity, ocean region or marine habitat type. However, fine-scale analysis of nematode microbiomes revealed a variety of novel ecological interactions, including putative parasites and symbionts, and potential associations with bacterial/archaeal taxa involved in nitrogen and methane cycling. Our results suggest that in marine habitats, free-living nematodes may utilize diverse and generalist foraging strategies that are not correlated with host genotype or feeding morphology. Furthermore, some abiotic factors such as geographic region

  18. Context Dependency of a Marine Defensive Symbiosis over a Wide Geographic Distribution

    Science.gov (United States)

    Lopanik, N.; Linneman, J.; Mathew, M.

    2016-02-01

    The invasive, temperate marine bryozoan Bugula neritina possesses an uncultured, vertically-transmitted bacterial symbiont that produces natural products known as bryostatins. These unpalatable polyketides protect the host larvae from predation. In the western Atlantic, two host genotypes were thought to be restricted to differing latitudes based on the presence of the defensive symbiont: undefended aposymbiotic Type N animals were found at high latitudes, while defended symbiotic Type S colonies were found at low latitudes, where predation pressure is higher. We found that the host genotypes are more widespread than previously thought, but that the symbiont appeared to be restricted to hosts at lower latitudes, regardless of host phylotype, leading to the question of what factors are involved in restricting the symbiont's range. We performed reciprocal transplant experiments of symbiotic and antibiotic-cured hosts, and measured host growth, a proxy for fitness. Our data indicate that possession of the symbiont appears to present a physiological cost to the host. This cost may be more pronounced at higher latitudes where the benefit of symbiosis is less apparent. In addition, preliminary evidence suggests that symbiont titer in a Type S colony from North Carolina transplanted to Virginia is reduced over a period of nearly 4 months. Taken together, these results suggest that a combination of factors may play a role in the distribution of the defensive symbiont: (i) hosts that possess the symbiont are outcompeted by aposymbiotic conspecifics at high latitude and reduced levels of predation pressure; and (ii) symbiont growth may be inhibited or sanctioned by the host at high latitudes. As defensive symbiosis is an important trait in marine habitats, understanding factors that affect the distribution of both the host and symbiont are necessary to fully appreciate the ecological impact of symbiosis.

  19. Inorganic chemical quality of European tap-water: 2. Geographical distribution

    International Nuclear Information System (INIS)

    Flem, B.; Reimann, C.; Birke, M.; Banks, D.; Filzmoser, P.; Frengstad, B.

    2015-01-01

    Highlights: • European scale comparison of tap water. • 579 tap water samples have been analyses for more than 60 parameters. • Chemical geographical distribution. • Water treatment processes. • Importance of geology on tap water quality. - Abstract: 579 tap water samples were collected at the European scale and analysed at a single laboratory for more than 60 parameters. This dataset is analysed here in terms of the spatial and national distribution of the analysed inorganic chemical parameters. The distribution of most parameters is controlled by various artificial and natural factors (land use, distribution network, water source and treatment, geographical location and geology). The distribution of nitrate can be interpreted in terms of land use and climate. Water treatment affects the distribution of phosphorus in tap water; especially the policy of adding phosphate to potable water in the UK to suppress plumbosolvency. The distribution of alkalinity, Ca, Mg, Sr and Li appears to reflect both water source (low in surface waters) and the geological contrast between base-poor crystalline rock terrains and carbonate rich sedimentary rock. The Scandinavian nations’ tap water shows the highest concentrations of most of the rare earth elements, probably reflecting their geological availability and mobility in low pH raw water sources. The distribution of fluoride, uranium and arsenic also appear to exhibit geological and source (groundwater versus surface water) controls. Hungary returns several high As results, which may reflect As-rich reducing groundwaters of the Pannonian basin. Much Estonian tap water reflects a very specific hydrochemical environment, namely Palaeozoic near-coastal aquifers, which yield deep, reducing or saline groundwater (possibly influenced by marine intrusion), enriched in Ba, B, Br − , Cl − , Eu, F − , I, Li, K, Mn and Na

  20. A checklist of sucking lice (Insecta: Phthiraptera: Anoplura) associated with Mexican wild mammals, including geographical records and a host-parasite list.

    Science.gov (United States)

    Sánchez-Montes, Sokani; Guzmán-Cornejo, Carmen; León-Paniagua, Livia; Rivas, Gerardo

    2013-01-01

    A checklist of 44 species of sucking lice (Insecta: Phthiraptera: Anoplura) recorded in Mexico, belonging to nine genera in six families is given, together with a list of the 63 species of Mexican wild mammal hosts with which they are associated. Summaries of the known geographical records and host relationships for each louse species are presented for each Mexican state. Data were compiled from published and original records, including three new locality records from the states of Oaxaca and Guerrero.

  1. Geography and major host evolutionary transitions shape the resource use of plant parasites.

    Science.gov (United States)

    Calatayud, Joaquín; Hórreo, José Luis; Madrigal-González, Jaime; Migeon, Alain; Rodríguez, Miguel Á; Magalhães, Sara; Hortal, Joaquín

    2016-08-30

    The evolution of resource use in herbivores has been conceptualized as an analog of the theory of island biogeography, assuming that plant species are islands separated by phylogenetic distances. Despite its usefulness, this analogy has paradoxically led to neglecting real biogeographical processes in the study of macroevolutionary patterns of herbivore-plant interactions. Here we show that host use is mostly determined by the geographical cooccurrence of hosts and parasites in spider mites (Tetranychidae), a globally distributed group of plant parasites. Strikingly, geography accounts for most of the phylogenetic signal in host use by these parasites. Beyond geography, only evolutionary transitions among major plant lineages (i.e., gymnosperms, commelinids, and eudicots) shape resource use patterns in these herbivores. Still, even these barriers have been repeatedly overcome in evolutionary time, resulting in phylogenetically diverse parasite communities feeding on similar hosts. Therefore, our results imply that patterns of apparent evolutionary conservatism may largely be a byproduct of the geographic cooccurrence of hosts and parasites.

  2. Host trait combinations drive abundance and canopy distribution of atmospheric bromeliad assemblages.

    Science.gov (United States)

    Chaves, Cleber Juliano Neves; Dyonisio, Júlio César; Rossatto, Davi Rodrigo

    2016-01-01

    Epiphytes are strongly dependent on the conditions created by their host's traits and a certain degree of specificity is expected between them, even if these species are largely abundant in a series of tree hosts of a given environment, as in the case of atmospheric bromeliads. Despite their considerable abundance in these environments, we hypothesize that stochasticity alone cannot explain the presence and abundance of atmospheric bromeliads on host trees, since host traits could have a greater influence on the establishment of these bromeliads. We used secondary and reforested seasonal forests and three distinct silvicultures to test whether species richness, phylogenetic diversity and functional diversity of trees can predict the differential presence, abundance and distribution of atmospheric bromeliads on hosts. We compared the observed parameters of their assemblage with null models and performed successive variance hierarchic partitions of abundance and distribution of the assemblage to detect the influence of multiple traits of the tree hosts. Our results do not indicate direct relationships between the abundance of atmospheric bromeliads and phylogenetic or functional diversity of trees, but instead indicate that bromeliads occurred on fewer tree species than expected by chance. We distinguished functional tree patterns that can improve or reduce the abundance of atmospheric bromeliads, and change their distribution on branches and trunk. While individual tree traits are related to increased abundance, species traits are related to the canopy distribution of atmospheric bromeliad assemblages. A balance among these tree functional patterns drives the atmospheric bromeliad assemblage of the forest patches. Published by Oxford University Press on behalf of the Annals of Botany Company.

  3. Interaction of landscape varibles on the potential geographical distribution of parrots in the Yucatan Peninsula, Mexico

    Directory of Open Access Journals (Sweden)

    Plasencia–Vázquez, A. H.

    2014-12-01

    Full Text Available The loss, degradation, and fragmentation of forested areas are endangering parrot populations. In this study, we determined the influence of fragmentation in relation to vegetation cover, land use, and spatial configuration of fragments on the potential geographical distribution patterns of parrots in the Yucatan Peninsula, Mexico. We used the potential geographical distribution for eight parrot species, considering the recently published maps obtained with the maximum entropy algorithm, and we incorporated the probability distribution for each species. We calculated 71 metrics/variables that evaluate forest fragmentation, spatial configuration of fragments, the ratio occupied by vegetation, and the land use in 100 plots of approximately 29 km², randomly distributed within the presence and absence areas predicted for each species. We also considered the relationship between environmental variables and the distribution probability of species. We used a partial least squares regression to explore patterns between the variables used and the potential distribution models. None of the environmental variables analyzed alone determined the presence/absence or the probability distribution of parrots in the Peninsula. We found that for the eight species, either due to the presence/absence or the probability distribution, the most important explanatory variables were the interaction among three variables, particularly the interactions among the total forest area, the total edge, and the tropical semi–evergreen medium– height forest. Habitat fragmentation influenced the potential geographical distribution of these species in terms of the characteristics of other environmental factors that are expressed together with the geographical division, such as the different vegetation cover ratio and land uses in deforested areas.

  4. Geographical Distribution of Taenia asiatica and Related Species

    Science.gov (United States)

    Jeon, Hyeong-Kyu; Rim, Han-Jong

    2009-01-01

    Geographical information of Taenia asiatica is reviewed together with that of T. solium and T. saginata. Current distribution of T. asiatica was found to be mostly from Asian countries: the Republic of Korea, China, Taiwan, Indonesia, and Thailand. Molecular genotypic techniques have found out more countries with T. asiatica from Japan, the Philippines, and Vietnam. Specimens used in this paper were collected from around the world and mostly during international collaboration projects of Korean foundations for parasite control activities (1995-2009) in developing countries. PMID:19885327

  5. Host country attractiveness for CDM non-sink projects

    International Nuclear Information System (INIS)

    Jung, Martina

    2006-01-01

    In the present study, CDM host countries are classified according to their attractiveness for CDM non-sink projects by using cluster analysis. The attractiveness of host countries for CDM non-sink projects is described by three indicators: mitigation potential, institutional CDM capacity and general investment climate. The results suggest that only a small proportion of potential host countries will attract most of the CDM investment. The CDM (non-sink) stars are China, India, Brazil, Argentina, Mexico, South Africa, Indonesia and Thailand. They are followed by attractive countries like Costa Rica, Trinidad and Tobago, Mongolia, Panama, and Chile. While most of the promising CDM host countries are located in Latin America and Asia, the general attractiveness of African host countries is relatively low (with the exception of South Africa). Policy implications of this rather inequitable geographical distribution of CDM project activities are discussed briefly

  6. Host-specific interactions with environmental factors shape the distribution of symbiodinium across the Great Barrier Reef.

    Directory of Open Access Journals (Sweden)

    Linda Tonk

    Full Text Available The endosymbiotic dinoflagellates (genus Symbiodinium within coral reef invertebrates are critical to the survival of the holobiont. The genetic variability of Symbiodinium may contribute to the tolerance of the symbiotic association to elevated sea surface temperatures (SST. To assess the importance of factors such as the local environment, host identity and biogeography in driving Symbiodinium distributions on reef-wide scales, data from studies on reef invertebrate-Symbiodinium associations from the Great Barrier Reef (GBR were compiled.The resulting database consisted of 3717 entries from 26 studies. It was used to explore ecological patterns such as host-specificity and environmental drivers structuring community complexity using a multi-scalar approach. The data was analyzed in several ways: (i frequently sampled host species were analyzed independently to investigate the influence of the environment on symbiont distributions, thereby excluding the influence of host specificity, (ii host species distributions across sites were added as an environmental variable to determine the contribution of host identity on symbiont distribution, and (iii data were pooled based on clade (broad genetic groups dividing the genus Symbiodinium to investigate factors driving Symbiodinium distributions using lower taxonomic resolution. The results indicated that host species identity plays a dominant role in determining the distribution of Symbiodinium and environmental variables shape distributions on a host species-specific level. SST derived variables (especially SSTstdev most often contributed to the selection of the best model. Clade level comparisons decreased the power of the predictive model indicating that it fails to incorporate the main drivers behind Symbiodinium distributions.Including the influence of different host species on Symbiodinium distributional patterns improves our understanding of the drivers behind the complexity of Symbiodinium

  7. The Geographical Aspect of Flexibility in Distribution Grids

    DEFF Research Database (Denmark)

    Kouzelis, Konstantinos; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

    2015-01-01

    , the reason for this is that flexibility is a multidimensional commodity. It can be associated with a unit or a system, a time-frame and a time-horizon of measuring it, its power magnitude and ramp rate, its energy shifting capability, its location and several other features. In this paper, the locational...... aggregation taking into account the distribution grid's radial structure. By aggregating the flexibility in this manner, different geographical points for offering it are defined. Through an illustrative market scenario, it is demonstrated how utilities might profit from their local flexibility by assisting...

  8. Population genetic structure of the lettuce root aphid, Pemphigus bursarius (L.), in relation to geographic distance, gene flow and host plant usage.

    Science.gov (United States)

    Miller, N J; Birley, A J; Overall, A D J; Tatchell, G M

    2003-09-01

    Microsatellite markers were used to examine the population structure of Pemphigus bursarius, a cyclically parthenogenetic aphid. Substantial allele frequency differences were observed between populations on the primary host plant (collected shortly after sexual reproduction) separated by distances as low as 14 km. This suggested that migratory movements occur over relatively short distances in this species. However, the degree of allele frequency divergence between populations was not correlated with their geographical separation, indicating that isolation by distance was not the sole cause of spatial genetic structuring. Significant excesses of homozygotes were observed in several populations. Substantial allele frequency differences were also found between aphids on the primary host and those sampled from a secondary host plant after several parthenogenetic generations at the same location in two successive years. This could have been due to the existence of obligately parthenogenetic lineages living on the secondary host or genetically divergent populations confined to different secondary host plant species but sharing a common primary host.

  9. Geographic distributions and ecology of ornamental Curcuma (Zingiberaceae) in Northeastern Thailand.

    Science.gov (United States)

    Khumkratok, Sutthira; Boongtiang, Kriangsuk; Chutichudet, Prasit; Pramaul, Pairot

    2012-10-01

    The genus Curcuma is a very important economic plant. Members of this genus were used as food, medicine and ornament plants. The objectives of this study were to examine the geographic distributions and ecological conditions in the natural habitats of Curcuma in Northeastern Thailand. Species diversity was examined using the line transect method. Ecological conditions of the species were examined using a sampling plot of 20 x 20 m. A total of five species were found including Curcuma angustifolia Roxb., C. alismatifolia Gagnep., C. gracillima Gagnep., C. parviflora Wall. and C. rhabdota. These species were in an altitudinal range between 290 m and 831 m above sea level. Four species (C. angustifolia, C. alismatifolia, C. gracillima and C. rhabdota) were distributed in open gaps in dry dipterocarp forest. One species, C. parviflora was found in the contact zone between dry dipterocarp and bamboo (Gigantochloa sp.) forest. C. rhabdota was found only in a habitat with high humidity and shading along the Thailand-Lao PDR border. Significant ecological conditions of the natural habitats of these Curcuma species were identified. Altitude is the most important factor when determining the geographic distributions of these Curcuma species in Northeastern Thailand.

  10. Andean Condor (Vultur gryphus) in Ecuador: Geographic Distribution, Population Size and Extinction Risk.

    Science.gov (United States)

    Naveda-Rodríguez, Adrián; Vargas, Félix Hernán; Kohn, Sebastián; Zapata-Ríos, Galo

    2016-01-01

    The Andean Condor (Vultur gryphus) in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA) for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km2. During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation.

  11. The geographical distribution and burden of trachoma in Africa.

    Directory of Open Access Journals (Sweden)

    Jennifer L Smith

    Full Text Available There remains a lack of epidemiological data on the geographical distribution of trachoma to support global mapping and scale up of interventions for the elimination of trachoma. The Global Atlas of Trachoma (GAT was launched in 2011 to address these needs and provide standardised, updated and accessible maps. This paper uses data included in the GAT to describe the geographical distribution and burden of trachoma in Africa.Data assembly used structured searches of published and unpublished literature to identify cross-sectional epidemiological data on the burden of trachoma since 1980. Survey data were abstracted into a standardised database and mapped using geographical information systems (GIS software. The characteristics of all surveys were summarized by country according to data source, time period, and survey methodology. Estimates of the current population at risk were calculated for each country and stratified by endemicity class.At the time of writing, 1342 records are included in the database representing surveys conducted between 1985 and 2012. These data were provided by direct contact with national control programmes and academic researchers (67%, peer-reviewed publications (17% and unpublished reports or theses (16%. Prevalence data on active trachoma are available in 29 of the 33 countries in Africa classified as endemic for trachoma, and 1095 (20.6% districts have representative data collected through population-based prevalence surveys. The highest prevalence of active trachoma and trichiasis remains in the Sahel area of West Africa and Savannah areas of East and Central Africa and an estimated 129.4 million people live in areas of Africa confirmed to be trachoma endemic.The Global Atlas of Trachoma provides the most contemporary and comprehensive summary of the burden of trachoma within Africa. The GAT highlights where future mapping is required and provides an important planning tool for scale-up and surveillance of trachoma

  12. Explaining the differential distribution of Clean Development Mechanism projects across host countries

    International Nuclear Information System (INIS)

    Winkelman, Andrew G.; Moore, Michael R.

    2011-01-01

    The Clean Development Mechanism (CDM) of the Kyoto Protocol represents an opportunity to involve all developing countries in the effort to reduce greenhouse gas emissions while also promoting sustainable development. To date, however, the majority of CDM projects have gone to emerging markets such as China, India, Brazil, and Mexico, while very few least developed countries have hosted projects. This paper investigates the differential distribution of CDM activities across countries. We develop a conceptual model for project profitability, which helps to identify potential country-level determinants of CDM activity. These potential determinants are employed as explanatory variables in regression analysis to explain the actual distribution of projects. Human capital and greenhouse gas emission levels influenced which countries have hosted projects and the amount of certified emission reductions (CER) created. Countries that offered growing markets for CDM co-products, such as electricity, were more likely to be CDM hosts, while economies with higher carbon intensity levels had greater CER production. These findings work against the least developed countries and help to explain their lack of CDM activity. - Research Highlights: → Regression models are used to explain the inter-country distribution of CDM projects. → Emissions and human capital are significant for hosting projects and CER creation. → An economy's emissions intensity is significant in determining CERs created. → Capacity building and electricity sector growth are significant in hosting projects. → The experience level for host countries in the CDM is significant for CER creation.

  13. PlanetLab Europe as Geographically-Distributed Testbed for Software Development and Evaluation

    Directory of Open Access Journals (Sweden)

    Dan Komosny

    2015-01-01

    Full Text Available In this paper, we analyse the use of PlanetLab Europe for development and evaluation of geographically-oriented Internet services. PlanetLab is a global research network with the main purpose to support development of new Internet services and protocols. PlanetLab is divided into several branches; one of them is PlanetLab Europe. PlanetLab Europe consists of about 350 nodes at 150 geographically different sites. The nodes are accessible by remote login, and the users can run their software on the nodes. In the paper, we study the PlanetLab's properties that are significant for its use as a geographically distributed testbed. This includes node position accuracy, services availability and stability. We find a considerable number of location inaccuracies and a number of services that cannot be considered as reliable. Based on the results we propose a simple approach to nodes selection in testbeds for geographically-oriented Internet services development and evaluation.

  14. Simulating spread of Bluetongue Virus by flying vectors between hosts on pasture

    DEFF Research Database (Denmark)

    Græsbøll, Kaare; Bødker, Rene; Enøe, Claes

    2012-01-01

    Bluetongue is a disease of ruminants which reached Denmark in 2007. We present a process-based stochastic simulation model of vector-borne diseases, where host animals are not confined to a central geographic farm coordinate, but can be distributed onto pasture areas. Furthermore vectors fly freely...

  15. Distribution and habitat in Mexico of Dactylopius Costa (Hemiptera: Dactylopiidae) and their cacti hosts (Cactaceae: Opuntioideae).

    Science.gov (United States)

    Chávez-Moreno, C K; Tecante, A; Casas, A; Claps, L E

    2011-01-01

    The distribution pattern of species of the genus Dactylopius Costa in Mexico was analyzed in relation to the distribution of their host plants (subfamily Opuntioideae) to evaluate the specificity of the insect-host association. The distribution of Dactylopius currently recognized is narrower than that of its hosts and probably is not representative. Therefore, a broader distribution of the Dactylopius species in correspondence with those of their hosts was hypothesized. Insects and their hosts were collected and georeferenced in 14 states of Mexico from 2005 to 2007. The distribution areas, maps, and habitat characteristics of Dactylopius, Opuntia sensu stricto, Nopalea and Cylindropuntia were determined on the basis of field collections and examination of museum collections. This information was complemented with information from the exhaustive examination of microscope slides from a local insect collection, plants from local herbaria, and literature reviews. The current distribution of the genus Dactylopius and its hosts included 22 and 25 states of Mexico, respectively, and Dactylopius had a continuous distribution according to its hosts, broader than recognized hitherto. The new georeferenced records of the five Mexican Dactylopius species are reported. Insects with morphological characteristics of D. confusus combined with those of D. salmianus were identified, as well as insects with characteristics of D. opuntiae combined with those of D. salmianus. These records suggest that the number of local Dactylopius species could be higher than previously thought or that possible new processes of hybridization between native and introduced species may be occurring.

  16. [New findings on the geographic distribution of the verrucarum group (Diptera: Psychodidae) in Colombia].

    Science.gov (United States)

    Bejarano, Eduar Elías; Sierra, Diana; Vélez, Iván Darío

    2003-09-01

    The incrimination of sand flies belonging to verrucarum species group in the leishmaniasis transmission underscores the need for a detailed information on the geographical distribution of these species. The current listing adds 34 new records that extend significantly the knowledge of the geographical distribution of the verrucarum group in Colombia. The most important new records pertain to Lutzomyia spinicrassa in the tropical dry forest of the Atlantic coast, Lutzomyia ovallesi in the Orinoco and Amazon River watersheds regions of Colombia, and the sympatric occurrence of Lutzomyia spinicrassa and Lutzomyia quasitownsendi in the eastern chain of the Andes mountains. Additionally, the municipal and altitudinal distributions are compiled for 19 new species recorded for Colombia. The series townsendi of the verrucarum group generally restricted to premontane and lower montane zones based on distribution data on Lutzomyia longiflocosa, L. quasitownsendi, Lutzomyia sauroida, L. spinicrassa, Lutzomyia torvida, Lutzomyia townsendi and Lutzomyia youngi. The series verrucarum is distributed from the tropical lowland to the montane zones, and includes species with wide geographical range (Lutzomyia evansi, Lutzomyia columbiana, L. ovallesi, Lutzomyia nuneztovari, Lutzomyia nevesi), and species of highly endemic distribution (Lutzomyia andina, Lutzomyia disiuncta, Lutzomyia moralesi, Lutzomyia antioquiensis). Members of the series pia (Lutzomyia pia, Lutzomyia limafalcaoae) and the series serrana (Lutzomyia serrana) occur from the tropical lowlands to the lower montane zones. The altitudinal divergences may be intrinsically tied to speciation process, especially as it relates to the climatic and geologic events that have affected the flora and fauna of the Andean region.

  17. Adding Biotic Interactions into Paleodistribution Models: A Host-Cleptoparasite Complex of Neotropical Orchid Bees.

    Directory of Open Access Journals (Sweden)

    Daniel Paiva Silva

    Full Text Available Orchid bees compose an exclusive Neotropical pollinators group, with bright body coloration. Several of those species build their own nests, while others are reported as nest cleptoparasites. Here, the objective was to evaluate whether the inclusion of a strong biotic interaction, such as the presence of a host species, improved the ability of species distribution models (SDMs to predict the geographic range of the cleptoparasite species. The target species were Aglae caerulea and its host species Eulaema nigrita. Additionally, since A. caerulea is more frequently found in the Amazon rather than the Cerrado areas, a secondary objective was to evaluate whether this species is increasing or decreasing its distribution given South American past and current climatic conditions. SDMs methods (Maxent and Bioclim, in addition with current and past South American climatic conditions, as well as the occurrences for A. caerulea and E. nigrita were used to generate the distribution models. The distribution of A. caerulea was generated with and without the inclusion of the distribution of E. nigrita as a predictor variable. The results indicate A. caerulea was barely affected by past climatic conditions and the populations from the Cerrado savanna could be at least 21,000 years old (the last glacial maximum, as well as the Amazonian ones. On the other hand, in this study, the inclusion of the host-cleptoparasite interaction complex did not statistically improve the quality of the produced models, which means that the geographic range of this cleptoparasite species is mainly constrained by climate and not by the presence of the host species. Nonetheless, this could also be caused by unknown complexes of other Euglossini hosts with A. caerulea, which still are still needed to be described by science.

  18. [Analysis of the geographical distribution of cases of leprosy. Rio de Janeiro, 2001-2012].

    Science.gov (United States)

    Gracie, Renata; Peixoto, Julia Novaes de Barros; Soares, Fabiane Bertoni Dos Reis; Hacker, Mariana de Andrea Vilas-Boas

    2017-05-01

    Studies have demonstrated that the geographical distribution of leprosy is related to different socioeconomic factors. This article aims to study the geographical distribution of leprosy in the state of Rio de Janeiro. The cases of leprosy reported in the 2001-2012 period were mapped according to municipality. Epidemiological and socioeconomic indicators were calculated. The ArcMap program was used for the construction of maps and Earth View to calculate the Bayesian rate. It was observed that leprosy is presented in hyper-endemic levels especially in the metropolitan area. However, there is also a reduction of the detection rate in the most recent study period. In municipalities in the metropolitan region and the north western region detection in children under 15 is high, indicating an active transmission situation. In municipalities in the south-central region and especially in the coastal region, there was a high proportion of cases diagnosed with level II disability, reflecting late diagnosis. There was no linear correlation between socioeconomic indicators and leprosy rate. These results contribute to the analysis of the geographical distribution of leprosy, important for the identification of areas for resource allocation, aiming to control and eliminate the disease.

  19. A review of the ticks (Acari, Ixodida of Brazil, their hosts and geographic distribution - 1. The State of Rio Grande do Sul, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Evans DE

    2000-01-01

    Full Text Available A review of the ticks (Acari, Ixodida of the State of Rio Grande do Sul, southern Brazil, was completed as a step towards a definitive list (currently indicated as 12 of such species, their hosts and distribution. The ticks: Argas miniatus (poultry, Ixodes loricatus (opossums, Amblyomma aureolatum (dogs, A. calcaratum (anteaters, A. cooperi (capybaras, A. nodosum (anteaters, A. tigrinum (dogs (Neotropical and Rhipicephalus sanguineus (dogs (introduced, cosmopolitan, Afrotropical were confirmed as present, in addition to the predominant, Boophilus microplus (cattle (introduced, pan-tropical, Oriental. Of the further 18 species thus far reported in the literature as present in the state, but unavailable for examination: only Ornithodoros brasiliensis (humans and their habitations (Neotropical, Ixodes affinis (deer (Nearctic/Neotropical and I. auritulus (birds (Nearctic/Neotropical/Afrotropical/ Australasian are considered likely; 13 species would benefit from corroborative local data but the majority appear unlikely; reports of A. maculatum (Nearctic/Neotropical, but circum-Caribbean are considered erroneous; the validity of A. fuscum is in doubt. The very recent, first known report of the tropical Anocentor nitens (horses(Nearctic/Neotropical, but still apparent absence of the tropical A. cajennense (catholic (Nearctic/Neotropical and the sub-tropical/temperate Ixodes pararicinus (cattle (Neotropical in Rio Grande do Sul are important for considerations on their current biogeographical distribution and its dynamics in South America. The state has relatively long established, introduced ("exotic", Old World tick species (B. microplus, R. sanguineus that continue to represent significant pests and disease vectors to their traditional, introduced domestic animal hosts, cattle and urban dogs. There are also indigenous, New World ticks (A. miniatus, O. brasiliensis, A. aureolatum, A. nitens, as both long established and possibly newly locally

  20. Reptilia, Gymnophthalmidae, Micrablepharus maximiliani (Reinhardt and Lutken, 1861: Distribution extension, new state record and geographic distribution map.

    Directory of Open Access Journals (Sweden)

    Moura, M. R.

    2010-01-01

    Full Text Available We provide records for Micrablepharus maximiliani from state of Minas Gerais and present a map representingits distribution. The record of M. maximiliani from municipality of Resplendor, Minas Gerais, represents a distributionextension of 1,050 km southern from the type locality at the municipality of Maruim, Sergipe. Others 57 new recordsare presented based on specimens housed in several Brazilian and Paraguayan herpetological collections, improving theknowledge on geographic distribution of M. maximiliani in South America.

  1. Staphylorchis cymatodes (Gorgoderidae: Anaporrhutinae) from carcharhiniform, orectolobiform and myliobatiform elasmobranchs of Australasia: low host specificity, wide distribution and morphological plasticity.

    Science.gov (United States)

    Cutmore, Scott C; Bennett, Michael B; Cribb, Thomas H

    2010-12-01

    Anaporrhutine gorgoderids (Digenea: Gorgoderidae: Anaporrhutinae) found in the body cavity of six species of elasmobranchs from the orders Carcharhiniformes, Myliobatiformes and Orectolobiformes from Australian waters were found to belong to the genus Staphylorchis. Although these specimens were morphologically variable, sequences of ITS2 and 28S ribosomal DNA from specimens from three host families and two host orders were identical. Based on morphological and molecular data these specimens were identified as the type-species of the genus, Staphylorchis cymatodes. New measurements are provided for S. cymatodes, and for the first time genetic data are presented for this species. In addition to providing new morphological and molecular data for S. cymatodes, the previously described species S. gigas, S. parisi and S. scoliodonii, are here synonymised with S. cymatodes. This implies that S. cymatodes, as conceived here, has remarkably low host-specificity, being recorded from eight elasmobranch species from four families and three orders, has a wide geographical distribution in the Indo-west Pacific from off India, in the Bay of Bengal, to Moreton Bay in the Coral Sea, and is morphologically plastic, with body size, size of specific organs and body shape differing dramatically between specimens from different host species. The genus Staphylorchis now contains only two valid species, S. cymatodes and S. pacifica. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  2. [Spatial distribution of occupational disease prevalence in Guangzhou and Foshan city by geographic information system].

    Science.gov (United States)

    Tan, Q; Tu, H W; Gu, C H; Li, X D; Li, R Z; Wang, M; Chen, S G; Cheng, Y J; Liu, Y M

    2017-11-20

    Objective: To explore the occupational disease spatial distribution characteristics in Guangzhou and Foshan city in 2006-2013 with Geographic Information System and to provide evidence for making control strategy. Methods: The data on occupational disease diagnosis in Guangzhou and Foshan city from 2006 through 2013 were collected and linked to the digital map at administrative county level with Arc GIS12.0 software for spatial analysis. Results: The maps of occupational disease and Moran's spatial autocor-relation analysis showed that the spatial aggregation existed in Shunde and Nanhai region with Moran's index 1.727, -0.003. Local Moran's I spatial autocorrelation analysis pointed out the "positive high incidence re-gion" and the "negative high incidence region" during 2006~2013. Trend analysis showed that the diagnosis case increased slightly then declined from west to east, increase obviously from north to south, declined from? southwest to northeast, high in the middle and low on both sides in northwest-southeast direction. Conclusions: The occupational disease is obviously geographical distribution in Guangzhou and Foshan city. The corresponding prevention measures should be made according to the geographical distribution.

  3. Mapping the geographical distribution of lymphatic filariasis in Zambia

    DEFF Research Database (Denmark)

    Mwase, Enala T; Stensgaard, Anna-Sofie; Nsakashalo-Senkwe, Mutale

    2014-01-01

    to be an important determinant of medium-high prevalence levels. CONCLUSIONS/SIGNIFICANCE: LF was found to be surprisingly widespread in Zambia, although in most places with low prevalence. The produced maps and the identified environmental correlates of LF infection will provide useful guidance for planning...... volunteers from 108 geo-referenced survey sites across Zambia were examined for circulating filarial antigens (CFA) with rapid format ICT cards, and a map indicating the distribution of CFA prevalences in Zambia was prepared. 78% of survey sites had CFA positive cases, with prevalences ranging between 1......% and 54%. Most positive survey sites had low prevalence, but six foci with more than 15% prevalence were identified. The observed geographical variation in prevalence pattern was examined in more detail using a species distribution modeling approach to explore environmental requirements for parasite...

  4. Molecular and morphological analysis reveals five new species of Zygophiala associated with flyspeck signs on plant hosts from China.

    Directory of Open Access Journals (Sweden)

    Liu Gao

    Full Text Available Species in the genus Zygophiala are associated with sooty blotch and flyspeck disease on a wide range of hosts. In this study, 63 Zygophiala isolates collected from flyspeck colonies on a range of plants from several regions of China were used for phylogeny, host range and geographic distribution analysis. Phylogenetic trees were constructed on four genes--internal transcribed spacer (ITS, partial translation elongation factor 1-alpha (TEF, β-tubulin (TUB2, and actin (ACT--both individually and in combination. Isolates were grouped into 11 clades among which five new species, Z. emperorae, Z. trispora, Z. musae, Z. inaequalis and Z. longispora, were described. Species of Zygophiala differed in observed host range and geographic distribution. Z. wisconsinensis and Z. emperorae were the most prevalent throughout the sampled regions of China, whereas Z. trispora, Z. musae, Z. inaequalis and Z. longispora were collected only in southern China. The hosts of Z. wisconsinensis and Z. emperorae were mainly in the family Rosaceae whereas Z. trispora, Z. musae, Z. inaequalis and Z. longispora were found mainly on banana (Musa spp.. Cross inoculation tests provided evidence of host specificity among SBFS species.

  5. Analysis Of Educational Services Distribution-Based Geographic Information System GIS

    OpenAIRE

    Waleed Lagrab; Noura AKNIN

    2015-01-01

    Abstract This study analyzes the spatial distribution of kindergarten facilities in the study area based on the Geographic Information Systems GIS in order to test an efficiency of GIS technology to redistribute the existing kindergarten and choose the best location in the future and applying the standard criteria for selecting the suitable locations for kindergarten. To achieve this goal the data and information are collected via interviews and comprehensive statistics on the education facil...

  6. Mycobacterium tuberculosis Lineage 4 comprises globally distributed and geographically restricted sublineages

    Science.gov (United States)

    Coscolla, Mireia; Liu, Qingyun; Trauner, Andrej; Fenner, Lukas; Rutaihwa, Liliana; Borrell, Sonia; Luo, Tao; Gao, Qian; Kato-Maeda, Midori; Ballif, Marie; Egger, Matthias; Macedo, Rita; Mardassi, Helmi; Moreno, Milagros; Tudo Vilanova, Griselda; Fyfe, Janet; Globan, Maria; Thomas, Jackson; Jamieson, Frances; Guthrie, Jennifer L.; Asante-Poku, Adwoa; Yeboah-Manu, Dorothy; Wampande, Eddie; Ssengooba, Willy; Joloba, Moses; Henry Boom, W.; Basu, Indira; Bower, James; Saraiva, Margarida; Vaconcellos, Sidra E. G.; Suffys, Philip; Koch, Anastasia; Wilkinson, Robert; Gail-Bekker, Linda; Malla, Bijaya; Ley, Serej D.; Beck, Hans-Peter; de Jong, Bouke C.; Toit, Kadri; Sanchez-Padilla, Elisabeth; Bonnet, Maryline; Gil-Brusola, Ana; Frank, Matthias; Penlap Beng, Veronique N.; Eisenach, Kathleen; Alani, Issam; Wangui Ndung’u, Perpetual; Revathi, Gunturu; Gehre, Florian; Akter, Suriya; Ntoumi, Francine; Stewart-Isherwood, Lynsey; Ntinginya, Nyanda E.; Rachow, Andrea; Hoelscher, Michael; Cirillo, Daniela Maria; Skenders, Girts; Hoffner, Sven; Bakonyte, Daiva; Stakenas, Petras; Diel, Roland; Crudu, Valeriu; Moldovan, Olga; Al-Hajoj, Sahal; Otero, Larissa; Barletta, Francesca; Jane Carter, E.; Diero, Lameck; Supply, Philip; Comas, Iñaki; Niemann, Stefan; Gagneux, Sebastien

    2016-01-01

    Generalist and specialist species differ in the breadth of their ecological niche. Little is known about the niche width of obligate human pathogens. Here we analyzed a global collection of Mycobacterium tuberculosis Lineage 4 clinical isolates, the most geographically widespread cause of human tuberculosis. We show that Lineage 4 comprises globally distributed and geographically restricted sublineages, suggesting a distinction between generalists and specialists. Population genomic analyses showed that while the majority of human T cell epitopes were conserved in all sublineages, the proportion of variable epitopes was higher in generalists. Our data further support a European origin for the most common generalist sublineage. Hence, the global success of Lineage 4 reflects distinct strategies adopted by different sublineages and the influence of human migration. PMID:27798628

  7. Coincidence between geographical distribution of Leptotrombidium scutellare and scrub typhus incidence in South Korea.

    Directory of Open Access Journals (Sweden)

    Jong Yul Roh

    Full Text Available To clarify the geographical distribution of scrub typhus vectors in Korea, a survey of larval trombiculid mites was conducted from 2005 to 2007 by collecting wild small mammals twice a year (spring and autumn at 24 sites nationwide. A total of 67,325 mites representing 4 genera and 14 species were collected from 783 trapped rodents, corresponding to a chigger index (number of chigger mites per rodent of 86.0. The predominant mite species were Leptotrombidium pallidum (52.6%, Leptotrombiduim scutellare (27.1%, Leptotrombidium palpale (8.2%, Leptotrombidium orientale (5.6%, and Neotrombicula tamiyai (1.7%. However, the proportions of L. scutellare in southern areas, including endemic provinces such as Jeollabuk-Do (34.3%, Jeollanam-Do (49.0%, and Gyeongsangnam-Do (88%, were relatively higher than in central Korean regions where L. pallidum was predominant. In autumn, the ratio of L. scutellare increased to 42% while the ratio of L. pallidum decreased. The geographical distribution map of the L. scutellare chigger index was identical to the incidence pattern of scrub typhus, whereas those of overall mites and L. pallidum showed no relationship with case incidence patterns. Distribution mapping analysis shows an identical geographical distribution of L. scutellare and epidemic incidence of scrub typhus in South Korea. L. pallidum could be another vector at all other parts of the Korean peninsula, including the eastern and northern regions that have a low level of scrub typhus incidence.

  8. Sequence Variation in Rhoptry Neck Protein 10 Gene among Toxoplasma gondii Isolates from Different Hosts and Geographical Locations

    Directory of Open Access Journals (Sweden)

    Yu ZHAO

    2017-09-01

    Full Text Available Background: Toxoplasma gondii, as a eukaryotic parasite of the phylum Apicomplexa, can infect almost all the warm-blooded animals and humans, causing toxoplasmosis. Rhoptry neck proteins (RONs play a key role in the invasion process of T. gondii and are potential vaccine candidate molecules against toxoplasmosis.Methods: The present study examined sequence variation in the rhoptry neck protein 10 (TgRON10 gene among 10 T. gondii isolates from different hosts and geographical locations from Lanzhou province during 2014, and compared with the corresponding sequences of strains ME49 and VEG obtained from the ToxoDB database, using polymerase chain reaction (PCR amplification, sequence analysis, and phylogenetic reconstruction by Bayesian inference (BI and maximum parsimony (MP. Results: Analysis of all the 12 TgRON10 genomic and cDNA sequences revealed 7 exons and 6 introns in the TgRON10 gDNA. The complete genomic sequence of the TgRON10 gene ranged from 4759 bp to 4763 bp, and sequence variation was 0-0.6% among the 12 T. gondii isolates, indicating a low sequence variation in TgRON10 gene. Phylogenetic analysis of TgRON10 sequences showed that the cluster of the 12 T. gondii isolates was not completely consistent with their respective genotypes.Conclusion: TgRON10 gene is not a suitable genetic marker for the differentiation of T. gondii isolates from different hosts and geographical locations, but may represent a potential vaccine candidate against toxoplasmosis, worth further studies.

  9. Sequence Variation in Rhoptry Neck Protein 10 Gene among Toxoplasma gondii Isolates from Different Hosts and Geographical Locations.

    Science.gov (United States)

    Zhao, Yu; Zhou, Donghui; Chen, Jia; Sun, Xiaolin

    2017-01-01

    Toxoplasma gondii, as a eukaryotic parasite of the phylum Apicomplexa, can infect almost all the warm-blooded animals and humans, causing toxoplasmosis. Rhoptry neck proteins (RONs) play a key role in the invasion process of T. gondii and are potential vaccine candidate molecules against toxoplasmosis. The present study examined sequence variation in the rhoptry neck protein 10 (TgRON10) gene among 10 T. gondii isolates from different hosts and geographical locations from Lanzhou province during 2014, and compared with the corresponding sequences of strains ME49 and VEG obtained from the ToxoDB database, using polymerase chain reaction (PCR) amplification, sequence analysis, and phylogenetic reconstruction by Bayesian inference (BI) and maximum parsimony (MP). Analysis of all the 12 TgRON10 genomic and cDNA sequences revealed 7 exons and 6 introns in the TgRON10 gDNA. The complete genomic sequence of the TgRON10 gene ranged from 4759 bp to 4763 bp, and sequence variation was 0-0.6% among the 12 T. gondii isolates, indicating a low sequence variation in TgRON10 gene. Phylogenetic analysis of TgRON10 sequences showed that the cluster of the 12 T. gondii isolates was not completely consistent with their respective genotypes. TgRON10 gene is not a suitable genetic marker for the differentiation of T. gondii isolates from different hosts and geographical locations, but may represent a potential vaccine candidate against toxoplasmosis, worth further studies.

  10. Geographical distribution of centenarians in Colombia: an analysis of three databases

    Directory of Open Access Journals (Sweden)

    Diego Rosselli

    2017-07-01

    Conclusions: Although the results are consistent with the number and geographical distribution of centenarians, some errors may be found in the date of birth stated in the records, which is the basis for estimating age in the three sources. Other factors potentially involved in the results may be physical activity, family and community support, low stress and healthy diet in these regions.

  11. The Current Landscape of US Pediatric Anesthesiologists: Demographic Characteristics and Geographic Distribution.

    Science.gov (United States)

    Muffly, Matthew K; Muffly, Tyler M; Weterings, Robbie; Singleton, Mark; Honkanen, Anita

    2016-07-01

    There is no comprehensive database of pediatric anesthesiologists, their demographic characteristics, or geographic location in the United States. We endeavored to create a comprehensive database of pediatric anesthesiologists by merging individuals identified as US pediatric anesthesiologists by the American Board of Anesthesiology, National Provider Identifier registry, Healthgrades.com database, and the Society for Pediatric Anesthesia membership list as of November 5, 2015. Professorial rank was accessed via the Association of American Medical Colleges and other online sources. Descriptive statistics characterized pediatric anesthesiologists' demographics. Pediatric anesthesiologists' locations at the city and state level were geocoded and mapped with the use of ArcGIS Desktop 10.1 mapping software (Redlands, CA). We identified 4048 pediatric anesthesiologists in the United States, which is approximately 8.8% of the physician anesthesiology workforce (n = 46,000). The median age of pediatric anesthesiologists was 49 years (interquartile range, 40-57 years), and the majority (56.4%) were men. Approximately two-thirds of identified pediatric anesthesiologists were subspecialty board certified in pediatric anesthesiology, and 33% of pediatric anesthesiologists had an identified academic affiliation. There is substantial heterogeneity in the geographic distribution of pediatric anesthesiologists by state and US Census Division with urban clustering. This description of pediatric anesthesiologists' demographic characteristics and geographic distribution fills an important gap in our understanding of pediatric anesthesia systems of care.

  12. Geographic distribution of hepatitis C virus genotype 6 subtypes in Thailand.

    Science.gov (United States)

    Akkarathamrongsin, Srunthron; Praianantathavorn, Kesmanee; Hacharoen, Nisachol; Theamboonlers, Apiradee; Tangkijvanich, Pisit; Tanaka, Yasuhito; Mizokami, Masashi; Poovorawan, Yong

    2010-02-01

    The nucleotide sequence of hepatitis C virus (HCV) genotype 6 found mostly in south China and south-east Asia, displays profound genetic diversity. The aim of this study to determine the genetic variability of HCV genotype 6 (HCV-6) in Thailand and locate the subtype distribution of genotype 6 in various geographic areas. Four hundred nineteen anti-HCV positive serum samples were collected from patients residing in - the central part of the country. HCV RNA positive samples based on reverse transcriptase- polymerase chain reaction (RT-PCR) of the 5'UTR were amplified with primers specific for the core and NS5B regions. Nucleotide sequences of both regions were analyzed for the genotype by phylogenetic analysis. To determine geographic distribution of HCV-6 subtypes, a search of the international database on subtype distribution in the respective countries was conducted. Among 375 HCV RNA positive samples, 71 had HCV-6 based on phylogenetic analysis of partial core and NS5B regions. The subtype distribution in order of predominance was 6f (56%), 6n (22%), 6i (11%), 6j (10%), and 6e (1%). Among the 13 countries with different subtypes of HCV-6, most sequences have been reported from Vietnam. Subtype 6f was found exclusively in Thailand where five distinct HCV-6 subtypes are circulating. HCV-6, which is endemic in south China and south-east Asia, displays profound genetic diversity and may have evolved over a considerable period of time. (c) 2009 Wiley-Liss, Inc.

  13. Linking parasite populations in hosts to parasite populations in space through Taylor's law and the negative binomial distribution.

    Science.gov (United States)

    Cohen, Joel E; Poulin, Robert; Lagrue, Clément

    2017-01-03

    The spatial distribution of individuals of any species is a basic concern of ecology. The spatial distribution of parasites matters to control and conservation of parasites that affect human and nonhuman populations. This paper develops a quantitative theory to predict the spatial distribution of parasites based on the distribution of parasites in hosts and the spatial distribution of hosts. Four models are tested against observations of metazoan hosts and their parasites in littoral zones of four lakes in Otago, New Zealand. These models differ in two dichotomous assumptions, constituting a 2 × 2 theoretical design. One assumption specifies whether the variance function of the number of parasites per host individual is described by Taylor's law (TL) or the negative binomial distribution (NBD). The other assumption specifies whether the numbers of parasite individuals within each host in a square meter of habitat are independent or perfectly correlated among host individuals. We find empirically that the variance-mean relationship of the numbers of parasites per square meter is very well described by TL but is not well described by NBD. Two models that posit perfect correlation of the parasite loads of hosts in a square meter of habitat approximate observations much better than two models that posit independence of parasite loads of hosts in a square meter, regardless of whether the variance-mean relationship of parasites per host individual obeys TL or NBD. We infer that high local interhost correlations in parasite load strongly influence the spatial distribution of parasites. Local hotspots could influence control and conservation of parasites.

  14. [Geographic data for Neotropical bats (Chiroptera)].

    Science.gov (United States)

    Noguera-Urbano, Elkin A; Escalante, Tania

    2014-03-01

    The global effort to digitize biodiversity occurrence data from collections, museums and other institutions has stimulated the development of important tools to improve the knowledge and conservation of biodiversity. The Global Biodiversity Information Facility (GBIF) enables and opens access to biodiversity data of 321 million of records, from 379 host institutions. Neotropical bats are a highly diverse and specialized group, and the geographic information about them is increasing since few years ago, but there are a few reports about this topic. The aim of this study was to analyze the number of digital records in GBIF of Neotropical bats with distribution in 21 American countries, evaluating their nomenclatural and geographical consistence at scale of country. Moreover, we evaluated the gaps of information on 1 degrees latitude x 1 degrees longitude grids cells. There were over 1/2 million records, but 58% of them have no latitude and longitude data; and 52% full fit nomenclatural and geographic evaluation. We estimated that there are no records in 54% of the analyzed area; the principal gaps are in biodiversity hotspots like the Colombian and Brazilian Amazonia and Southern Venezuela. In conclusion, our study suggests that available data on GBIF have nomenclatural and geographic biases. GBIF data represent partially the bat species richness and the main gaps in information are in South America.

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

    Science.gov (United States)

    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...

  16. Geographic distribution and ecological niche of plague in sub-Saharan Africa

    DEFF Research Database (Denmark)

    Neerinckx, Simon B; Peterson, Andrew T; Gulinck, Hubert

    2008-01-01

    Background Plague is a rapidly progressing, serious illness in humans that is likely to be fatal if not treated. It remains a public health threat, especially in sub-Saharan Africa. In spite of plague's highly focal nature, a thorough ecological understanding of the general distribution pattern...... of plague across sub-Saharan Africa has not been established to date. In this study, we used human plague data from sub-Saharan Africa for 1970-2007 in an ecological niche modeling framework to explore the potential geographic distribution of plague and its ecological requirements across Africa. Results We...... predict a broad potential distributional area of plague occurrences across sub-Saharan Africa. General tests of model's transferability suggest that our model can anticipate the potential distribution of plague occurrences in Madagascar and northern Africa. However, generality and predictive ability tests...

  17. Olive anthracnose: a yield- and oil quality-degrading disease caused by several species of Colletotrichum that differ in virulence, host preference and geographical distribution.

    Science.gov (United States)

    Talhinhas, Pedro; Loureiro, Andreia; Oliveira, Helena

    2018-03-08

    Olive anthracnose causes fruit rot leading to its drop or mummification, resulting in yield losses and the degradation of oil quality. The disease is caused by diverse species of Colletotrichum, mostly clustering in the C. acutatum species complex. Colletotrichum nymphaeae and C. godetiae are the prevalent species in the Northern Hemisphere, whereas C. acutatum sensu stricto is the most frequent species in the Southern Hemisphere, although it is recently and quickly emerging in the Northern Hemisphere. The disease has been reported from all continents, but it attains higher incidence and severity in the west of the Mediterranean Basin, where it is endemic in traditional orchards of susceptible cultivars. The pathogens are able to survive on vegetative organs. On the fruit surface, infections remain quiescent until fruit maturity, when typical anthracnose symptoms develop. Under severe epidemics, defoliation and death of branches can also occur. Pathogen species differ in virulence, although this depends on the cultivar. The selection of resistant cultivars depends strongly on pathogen diversity and environmental conditions, posing added difficulties to breeding efforts. Chemical disease control is normally achieved with copper-based fungicides, although this may be insufficient under highly favourable disease conditions and causes concern because of the presence of fungicide residues in the oil. In areas in which the incidence is high, farmers tend to anticipate harvest, with consequences in yield and oil characteristics. Olive production systems, harvest and post-harvest processing have experienced profound changes in recent years, namely new training systems using specific cultivars, new harvest and processing techniques and new organoleptic market requests. Changes are also occurring in both the geographical distribution of pathogen populations and the taxonomic framework. In addition, stricter rules concerning pesticide use are likely to have a strong impact

  18. Hepatitis B and hepatitis C viruses: a review of viral genomes, viral induced host immune responses, genotypic distributions and worldwide epidemiology

    Directory of Open Access Journals (Sweden)

    Umar Saeed

    2014-04-01

    Full Text Available Hepatitis B and hepatitis C viruses (HCV are frequently propagating blood borne pathogens in global community. Viral hepatitis is primarily associated with severe health complications, such as liver cirrhosis, hepatocellular carcinoma, hepatic fibrosis and steatosis. A literature review was conducted on hepatitis B virus (HBV, HBV genome, genotypic distribution and global epidemiology of HBV, HCV, HCV genome, HCV and host immune responses, HCV genotypic distribution and global epidemiology. The valued information was subjected for review. HBV has strict tissue tropism to liver. The virus infecting hepatocytes produces large amount of hepatitis B surface antigen particles which lack the DNA. It has capability to integrate into host genome. It has been found that genotype C is most emerging genotype associated with more severe liver diseases (cirrhosis. The approximate prevalence rate of genotype C is 27.7% which represents a major threat to future generations. Approximately 8% of population is chronic carrier of HBV in developing countries. The chronic carrier rate of HBV is 2%-7% in Middle East, Eastern and Southern Europe, South America and Japan. Among HCV infected individuals, 15% usually have natural tendency to overcome acute viral infection, where as 85% of individuals were unable to control HCV infection. The internal ribosomal entry site contains highly conserved structures important for binding and appropriate positioning of viral genome inside the host cell. HCV infects only in 1%-10% of hepatocytes, but production of tumor necrosis factor alpha (from CD8+ cells and interferon-gamma cause destruction of both infected cells and non-infected surrounding cells. Almost 11 genotypes and above 100 subtypes of HCV exists worldwide with different geographical distribution. Many efforts are still needed to minimize global burden of these infections. For the complete eradication of HBV (just like small pox and polio via vaccination strategies

  19. Species composition and geographical distribution of Saharan scorpion fauna, Morocco

    Directory of Open Access Journals (Sweden)

    Oulaid Touloun

    2016-11-01

    Full Text Available Objective: To describe the species composition of scorpions and to study its geographical distribution in Laayoune-Sakia El Hamra and Dakhla-Oued Ed Dahab regions in July 2014. Methods: To locate scorpions, the ground was examined through searching the places under the stones, rocks and in burrows. The nocturnal missions were also conducted using portable ultraviolet lamps. The scorpions were subsequently identified in the laboratory. Results: The results of the investigations in these regions showed the presence of five scorpion species, two of which Androctonus gonneti and Buthus bonito were endemic in Morocco. Conclusions: This work is allowed to complete the inventory of the studied scorpion fauna and provides some considerations on the distribution patterns in the study area.

  20. Local knowledge, use pattern and geographical distribution of Moringa oleifera Lam. (Moringaceae) in Nigeria.

    Science.gov (United States)

    Popoola, Jacob O; Obembe, Olawole O

    2013-11-25

    All parts of Moringa oleifera are medicinally valuable with overlapping uses in treating myriads of ailments and diseases including body pains and weakness, fever, asthma, cough, blood pressure, arthritis, diabetes, epilepsy, wound, and skin infection. Moringa also has robust ability to challenge terminal diseases such as HIV/AIDs infections, chronic anemia, cancer, malaria and hemorrhage. The present study was to obtain ethnobotanical information on the use and local knowledge variation, geographical distribution, and to collect different landraces of Moringa oleifera from the different agro-ecological regions in Nigeria, for further studies. Ethnobotanical data were collected through face to face interviews, semi structured questionnaires and discussions with selected people who had knowledge about the plant. The fidelity level (FL %) and use value for different use categories of Moringa oleifera and its parts were estimated. The variation in ethnobotanical knowledge was evaluated by comparing the mean use value among ethnic, gender and age groups using sample T test. Garmi GPS was used to determine the locations (latitude and longitude) and height in different areas to assess the geographical spread of the species. Seven (7) categories of use (Food, medicine, fodder, fencing, firewood, gum and coagulant) were recorded for Moringa oleifera. Food and medicinal uses showed highest fidelity level while the leaves and the seeds were the plant parts most utilized for the same purposes. There were significant differences among the ethnic, gender and age groups regarding the ethno-botanical use value. The geographical distribution pattern shows that the Moringa oleifera is well distributed in all ecological zones of Nigeria, well adapted to the varied climatic conditions and gaining unprecedented awareness among the people. Though considered an introduced species, Moringa oleifera has found wide acceptance, recognition and usefulness among the various ethnicities in the

  1. Geographic variability of Escherichia coli ribotypes from animals in Idaho and Georgia.

    Science.gov (United States)

    Hartel, Peter G; Summer, Jacob D; Hill, Jennifer L; Collins, J Victoria; Entry, James A; Segars, William I

    2002-01-01

    Several genotypic methods have been developed for determining the host origin of fecal bacteria in contaminated waters. Some of these methods rely on a host origin database to identify environmental isolates. It is not well understood to what degree these host origin isolates are geographically variable (i.e., cosmopolitan or endemic). This is important because a geographically limited host origin database may or may not be universally applicable. The objective of our study was to use one genotypic method, ribotyping, to determine the geographic variability of the fecal bacterium, Escherichia coli, from one location in Idaho and three locations in Georgia for cattle (Bos taurus), horse (Equus caballus), swine (Sus scrofa), and chicken (Gallus gallus domesticus). A total of 568 fecal E. coli isolates from Kimberly, ID (125 isolates), Athens, GA (210 isolates), Brunswick, GA (102 isolates), and Tifton, GA (131 isolates), yielded 213 ribotypes. The percentage of ribotype sharing within an animal species increased with decreased distance between geographic locations for cattle and horses, but not for swine and chicken. When the E. coli ribotypes among the four host species were compared at one location, the percent of unshared ribotypes was 86, 89, 81, and 79% for Kimberly, Athens, Brunswick, and Tifton, respectively. These data suggest that there is good ribotype separation among host animal species at each location. The ability to match environmental isolates to a host origin database may depend on a large number of environmental and host origin isolates that ideally are not geographically separated.

  2. Diversity of helminth parasites in aquatic invertebrate hosts in Latin America: how much do we know?

    Science.gov (United States)

    Aguirre-Macedo, M L; May-Tec, A L; Martínez-Aquino, A; Cremonte, F; Martorelli, S R

    2017-03-01

    Helminths in aquatic invertebrate hosts have been overlooked in comparison with vertebrate hosts. Therefore, the known diversity, ecology and distribution of these host-parasite systems are very limited in terms of their taxonomic diversity, habitat and geographic regions. In this study we examined the published literature on helminth parasites of aquatic invertebrates from Latin America and the Caribbean (LAC) to identify the state of the knowledge in the region and to identify patterns of helminth diversity. Results showed that 67% of the literature is from Argentina, Mexico and Brazil. We found records for 772 host-parasite associations. Most records relate to medically or economically important hosts. Molluscs were the most studied host group with 377 helminth records (80% trematodes). The lymnaeids and planorbids were the most studied molluscs across LAC. Arthropods were the second most studied host group with 78 helminth records (trematodes 38%, cestodes 24% and nematodes 20%), with shrimps and crabs being the most studied hosts. Host species with the largest number of helminth taxa were those with a larger sampling effort through time, usually in a small country region. No large geographical-scale studies were identified. In general, the knowledge is still too scarce to allow any zoogeographical or helminth diversity generalization, as most hosts have been studied locally and the studies on invertebrate hosts in LAC are substantially uneven among countries.

  3. Hospital distribution in a metropolitan city: assessment by a geographical information system grid modelling approach

    Directory of Open Access Journals (Sweden)

    Kwang-Soo Lee

    2014-05-01

    Full Text Available Grid models were used to assess urban hospital distribution in Seoul, the capital of South Korea. A geographical information system (GIS based analytical model was developed and applied to assess the situation in a metropolitan area with a population exceeding 10 million. Secondary data for this analysis were obtained from multiple sources: the Korean Statistical Information Service, the Korean Hospital Association and the Statistical Geographical Information System. A grid of cells measuring 1 × 1 km was superimposed on the city map and a set of variables related to population, economy, mobility and housing were identified and measured for each cell. Socio-demographic variables were included to reflect the characteristics of each area. Analytical models were then developed using GIS software with the number of hospitals as the dependent variable. Applying multiple linear regression and geographically weighted regression models, three factors (highway and major arterial road areas; number of subway entrances; and row house areas were statistically significant in explaining the variance of hospital distribution for each cell. The overall results show that GIS is a useful tool for analysing and understanding location strategies. This approach appears a useful source of information for decision-makers concerned with the distribution of hospitals and other health care centres in a city.

  4. [Species composition and geographical distribution of threatened fishes in Yunnan Province of Southwest China].

    Science.gov (United States)

    Zhang, Qian; Zhong, Jin-Xin

    2013-05-01

    Based on the related published papers, and by using Geographic Information System (ArcGIS 9.3), this paper analyzed the species composition and geographical distribution of threatened fishes in Yunnan Province of Southwest China. There were 83 threatened species living in the Province, belonging to 5 orders, 13 families, and 47 genera. Cypriniformes was absolutely dominant, with 64 species, followed by Siluriformes, with 16 species. Cyprinidae fishes had 51 species, accounting for 79.7% of Cypriniformes. The most species of Cyprinid fishes were of Barbinae (14 species), Cyprininae (10 species), and Cultrinae (10 species). The threatened fishes could be divided into two zoogeographical regions, i. e., Tibetan Plateau region and Oriental region, and their species composition and geographical distribution were resulted from the historical evolution adapted to the related environments. Whatever in rivers and in lakes, the Cyprinid fishes were both absolutely dominant, occupying 36.1% and 31.3% of the total, respectively. The Cyprinid fishes in rivers were mostly of endangered species, while those in lakes were mostly of vulnerable species. The factors affecting the threatened fishes in the Province were discussed from the two aspects of geodynamic evolution and present situation.

  5. A revised geographical range for Liolaemus elongates Koslowsky, 1896 (Squamata: Liolaemini in Argentina: review of reported and new-data based distribution with new localities

    Directory of Open Access Journals (Sweden)

    Ignacio Minoli

    2013-12-01

    Full Text Available Estimating the effective geographical ranges of species is central to species-oriented conservation and management. In this paper, we review the geographical distribution of Liolaemus elongatus Koslowsky, 1896 with three new records for northern Chubut and southern Río Negro provinces, Argentina. Based on detailed locality records pooled from multiple data sources, including new records obtained for this study, we revise the range of L. elongatus sensu stricto and provide geographical distribution maps comparing the previously recognized range to that proposed herein. Our results show that L. elongatus possesses a much more limited geographic distribution than previously thought, being restricted to areas south of 38°S latitude; the newly proposed range is merely half the species formerly recognized geographical distribution.

  6. Host-parasite interactions in sympatric and allopatric populations of European bitterling.

    Science.gov (United States)

    Francová, Kateřina; Ondračková, Markéta

    2011-09-01

    Susceptibility to parasite infection was examined in a field experiment for four populations of 0+ juvenile European bitterling (Rhodeus amarus): one sympatric to local parasite fauna, one allopatric, and two hybrid populations. Significantly higher parasite abundance was recorded in the allopatric bitterling population, suggesting a maladaptation of parasites to their sympatric host. Type of parasite life cycle played an important role in host-parasite interactions. While the abundance of allogenic species between populations was comparable, a significant difference was found in abundance of autogenic parasite species between fish populations, with the allopatric population more infected. These results correspond with a prediction of higher dispersion probability and higher gene flow among geographically distant populations of allogenic species as compared to autogenic species. Increased susceptibility to parasites that do not occur within the natural host's geographical distribution was found in the allopatric host, but only for autogenic species. A difference in infection susceptibility was detected among populations of early-hatched bitterling exposed to infection during a period of high parasite abundance and richness in the environment. Differences in parasite abundance and species diversity among populations diminished, however, with increasing time of exposure. No difference was found within late-hatched populations, probably due to a lower probability of infection in late-hatched cohorts.

  7. Geographic Distribution of Teaching Talent in California. Consultant's Report Prepared for the State Committee on Public Education.

    Science.gov (United States)

    Guthrie, James; And Others

    The central purpose of this study was to examine the relationship between distribution of teaching talent and geographic location of local school districts of California. School districts were assigned to one of four geographic categories (urban, suburban, rural, or small urban centers). Each category's teaching talent was assessed on six measures…

  8. Factors Influence on Geographic Distribution of Physicians in Selected Countries: A Review Article

    Directory of Open Access Journals (Sweden)

    Amir Ashkan Nasiripour

    2013-12-01

    Full Text Available Background: One of the most important inequalities of providing health services is misdistribution of human resources, especially physicians. Many factors contribute to the distribution of physicians in different regions. The present study was aimed to explore the effective factors in distributing physicians in different countries. Methods: This study is a systematic review, in which the data were gathered through literature review, online searches in multiple databases and relevant organizations’ websites. Later, the collected data were classified using content analysis method, and consequently, they were illustrated in comparative matrix. Results: The factors that influence the dispersion of the physicians are divided into 4 main groups. Firstly, Geographic and Demographic factors of the region such as, population, age, gender and climate. Secondly, Health factors of the region and the country such as, the number of hospitals, health centers and health indicators. Thirdly, Economic, Social and Political factors of the region such as, economic growth, culture and believes. And finally, the factors related to physicians' characteristics and motivation such as, age, gender and the compensation system. Conclusion: There are different reasons why physicians spread in different countries’ geographical regions. Regarding the unequal distribution of physicians in Iran, identifying these influential reasons and also the factors affecting the distribution of physicians, and the impact of each one of these, can lead to a fair and equal distribution of resources of the health sector.

  9. Potential impacts of climatic change upon geographical distributions of birds

    DEFF Research Database (Denmark)

    Huntley, Brian; Collingham, Yvonne C.; Green, Rhys E.

    2006-01-01

    likely to decrease. Species with restricted distributions and specialized species of particular biomes are likely to suffer the greatest impacts. Migrant species are likely to suffer especially large impacts as climatic change alters both their breeding and wintering areas, as well as critical stopover......Potential climatic changes of the near future have important characteristics that differentiate them from the largest magnitude and most rapid of climatic changes of the Quaternary. These potential climatic changes are thus a cause for considerable concern in terms of their possible impacts upon...... biodiversity. Birds, in common with other terrestrial organisms, are expected to exhibit one of two general responses to climatic change: they may adapt to the changed conditions without shifting location, or they may show a spatial response, adjusting their geographical distribution in response...

  10. Ecophysiological Traits of Leaves of Three Marsilea Species Distributed in Different Geographical Regions

    Directory of Open Access Journals (Sweden)

    Tai-Chung Wu

    2011-11-01

    Full Text Available Marsilea, an amphibian fern genus (containing ca. 80 species characterized by their unusual leaves and reproductive structures, is distributed over the five continents. To investigate the adaptation traits of three Marsilea species (M. crenata, M. quadrifolia, and M. schelpiana, distributed in different geographic regions, to terrestrial conditions, we compared morphological features, optical properties and photosynthetic performance of leaflets of the three species grown in terrestrial environment. The results showed that leaflets of the three species had significant differences in some of the ecophysiogical traits. Among the three species, M. quadrifolia (distributed in temperate region where receiving low precipitation had the highest trichome density on its leaflet surface and the highest water use efficiency, M. schelpiana (mainly in southern Africa where accepting high level of solar irradiance had the tallest petiole and the highest leaf dissection index, total stomatal pore area index, PSII electron transport rate and photosaturated photosynthetic rate, M. crenata (mainly in southeastern Asia region where receiving high precipitation and with high humidity had the lowest leaf dissection index and water use efficiency. Accordingly, leaf characteristics of the three Marsilea species reflect the climate pattern of their habitats. The results also suggest that water availability and light intensity are two of the important factors contributing to the geographic distribution of the three species.

  11. Comparison of geographic distributions of Irritable Bowel Syndrome with Inflammatory Bowel Disease fail to support common evolutionary roots: Irritable Bowel Syndrome and Inflammatory Bowel Diseases are not related by evolution.

    Science.gov (United States)

    Szilagyi, Andrew; Xue, Xiaoqing

    2018-01-01

    Irritable Bowel Syndrome (IBS) shares overlapping symptoms and some features of pathogenesis with Inflammatory Bowel Diseases (IBD: Crohn's disease [CD], and Ulcerative Colitis [UC]). Geographic markers such as latitude/sunshine and more recently lactase population distributions are found to be correlated with IBD. As a result of clinical and pathogenic similarities between the 2 conditions, some authorities questioned whether a connection exists between them. We compare IBS directly with IBD, and indirectly with geographic markers associated with IBD, in order to evaluate possible evolutionary links between IBS and IBD. Similar correlations may link IBS as a precursor to IBD and possibly other conditions which are geographically connected with IBD. Data from four systematic reviews on IBD incidence and prevalence, IBS prevalence, and lactase distributions were included. Pearson's correlations were used for comparisons, with IBD values log-transformed because of skewed distribution. The articles provided 18-28 complete set of national data. Direct comparison between IBS and IBD showed no significant correlations (r = -0.14, r = -0.06 for CD and UC prevalence, r = -0.10 for CD incidence). Indirect comparisons also failed to show correlations of IBS with lactase distributions (r = -0.17), sunshine (r = -0.2) or latitude (r = 0.097); however, there was significant correlation between lactase distributions and CD incidence (r = -0.84), prevalence (r = -0.55) and UC prevalence (r = -0.59). Both sunshine (r= -0.53) and latitude (r = 0.58) are also significantly related to CD incidence. It is concluded that IBS and IBD do not follow similar global geographic patterns. This suggests a lack of an evolutionary genetic background coincident with emergence of lactase persistence. As well, vitamin D has no obvious impact on development of IBS. Similarities with IBD may result from sub groups (not yet identified) within the current Rome

  12. Assessing the diversity, host-specificity and infection patterns of apicomplexan parasites in reptiles from Oman, Arabia.

    Science.gov (United States)

    Maia, João P; Harris, D James; Carranza, Salvador; Goméz-Díaz, Elena

    2016-11-01

    Understanding the processes that shape parasite diversification, their distribution and abundance provides valuable information on the dynamics and evolution of disease. In this study, we assessed the diversity, distribution, host-specificity and infection patterns of apicomplexan parasites in amphibians and reptiles from Oman, Arabia. Using a quantitative PCR approach we detected three apicomplexan parasites (haemogregarines, lankesterellids and sarcocystids). A total of 13 haemogregarine haplotypes were identified, which fell into four main clades in a phylogenetic framework. Phylogenetic analysis of six new lankesterellid haplotypes revealed that these parasites were distinct from, but phylogenetically related to, known Lankesterella species and might represent new taxa. The percentage of infected hosts (prevalence) and the number of haemogregarines in the blood (parasitaemia) varied significantly between gecko species. We also found significant differences in parasitaemia between haemogregarine parasite lineages (defined by phylogenetic clustering of haplotypes), suggesting differences in host-parasite compatibility between these lineages. For Pristurus rupestris, we found significant differences in haemogregarine prevalence between geographical areas. Our results suggest that host ecology and host relatedness may influence haemogregarine distributions and, more generally, highlight the importance of screening wild hosts from remote regions to provide new insights into parasite diversity.

  13. Comparison of the geographical distribution of feline immunodeficiency virus and feline leukemia virus infections in the United States of America (2000-2011).

    Science.gov (United States)

    Chhetri, Bimal K; Berke, Olaf; Pearl, David L; Bienzle, Dorothee

    2013-01-05

    Although feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) have similar risk factors and control measures, infection rates have been speculated to vary in geographic distribution over North America. Since both infections are endemic in North America, it was assumed as a working hypothesis that their geographic distributions were similar. Hence, the purpose of this exploratory analysis was to investigate the comparative geographical distribution of both viral infections. Counts of FIV (n=17,108) and FeLV (n=30,017) positive serology results (FIV antibody and FeLV ELISA) were obtained for 48 contiguous states and District of Columbia of the United States of America (US) from the IDEXX Laboratories website. The proportional morbidity ratio of FIV to FeLV infection was estimated for each administrative region and its geographic distribution pattern was visualized by a choropleth map. Statistical evidence of an excess in the proportional morbidity ratio from unity was assessed using the spatial scan test under the normal probability model. This study revealed distinct spatial distribution patterns in the proportional morbidity ratio suggesting the presence of one or more relevant and geographically varying risk factors. The disease map indicates that there is a higher prevalence of FIV infections in the southern and eastern US compared to FeLV. In contrast, FeLV infections were observed to be more frequent in the western US compared to FIV. The respective excess in proportional morbidity ratio was significant with respect to the spatial scan test (p < 0.05). The observed variability in the geographical distribution of the proportional morbidity ratio of FIV to FeLV may be related to the presence of an additional or unique, but yet unknown, spatial risk factor. Putative factors may be geographic variations in specific virus strains and rate of vaccination. Knowledge of these factors and the geographical distributions of these infections can inform

  14. A global meta-analysis of Tuber ITS rDNA sequences: species diversity, host associations and long-distance dispersal

    Science.gov (United States)

    Gregory M. Bonito; Andrii P. Gryganskyi; James M. Trappe; Rytas. Vilgalys

    2010-01-01

    Truffles (Tuber) are ectomycorrhizal fungi characterized by hypogeous fruitbodies. Their biodiversity, host associations and geographical distributions are not well documented. ITS rDNA sequences of Tuber are commonly recovered from molecular surveys of fungal communities, but most remain insufficiently identified making it...

  15. Differentiation between diploid and tetraploid Centaurea phrygia: mating barriers, morphology and geographic distribution

    Czech Academy of Sciences Publication Activity Database

    Koutecký, P.; Štěpánek, Jan; Baďurová, T.

    2012-01-01

    Roč. 84, č. 1 (2012), s. 1-32 ISSN 0032-7786 R&D Projects: GA ČR GA206/09/1126 Institutional research plan: CEZ:AV0Z60050516 Institutional support: RVO:67985939 Keywords : geographic distribution * polyploidy * reproductive isolation Subject RIV: EF - Botanics Impact factor: 2.833, year: 2012

  16. Geographic distribution and conservation status of Caiman latirostris (Crocodylia, Alligatoridae in Uruguay

    Directory of Open Access Journals (Sweden)

    Claudio Borteiro

    2006-12-01

    Full Text Available Populations of Caiman latirostris are known to occur in Uruguay but their geographic distribution remains uncertain. This work presents anupdate of the species distribution and conservation status in Uruguay. Surveys conducted by the authors confirmed the presence of this species in the previously known distribution range of northwestern Uruguay, where it seems to be widespread and relatively abundant in contrast to earlier reports. We report new localities for C. latirostris, most relevant being those of the Cebollatí and Tacuarí Rivers, and the Pelotas, India Muerta and San Miguel stream basins, which significantly expand its distribution through important wetlands in the eastern part of the country. The overall distribution is coincident with different landscape types, where lagoons, artificial impoundments, livestock waterholes, rivers, streams, creeks and marshes are inhabited by caiman. Illegal non-commercial hunting was detected all over the country.

  17. Distribution System Augmented by DC Links for Increasing the Hosting Capacity of PV Generation

    DEFF Research Database (Denmark)

    Chaudhary, Sanjay; Demirok, Erhan; Teodorescu, Remus

    2012-01-01

    This paper presents a concept of enhancing the photovoltaic (PV) power generation hosting capacity of distribution networks. Distribution network serving electrical energy to farm settlements was selected as an example for their large roof area available for PV installation. Further, they are cha......This paper presents a concept of enhancing the photovoltaic (PV) power generation hosting capacity of distribution networks. Distribution network serving electrical energy to farm settlements was selected as an example for their large roof area available for PV installation. Further......, they are characterized by long radial feeders. Such feeders suffer from voltage rise and transformer overloading problems as the total number and capacity of the PV installations increase. The distribution network can be augmented by dc distribution links with power electronic converter interfaces to the traditional ac...... distribution systems. It is shown here that the dc links can be used to interconnect the different radial feeders and the excess power thus could be transferred to the nearby industrial load-center....

  18. Geographic Distribution of CT, MRI and PET Devices in Japan: A Longitudinal Analysis Based on National Census Data.

    Science.gov (United States)

    Matsumoto, Masatoshi; Koike, Soichi; Kashima, Saori; Awai, Kazuo

    2015-01-01

    Japan has the most CT and MRI scanners per unit population in the world; however, the geographic distribution of these technologies is currently unknown. Moreover, nothing is known of the cause-effect relationship between the number of diagnostic imaging devices and their geographic distribution. Data on the number of CT, MRI and PET devices and that of their utilizations in all 1829 municipalities of Japan was generated, based on the Static Survey of Medical Institutions conducted by the government. The inter-municipality equity of the number of devices or utilizations was evaluated with Gini coefficient. Between 2005 and 2011, the number of CT, MRI and PET devices in Japan increased by 47% (8789 to 12945), 19% (5034 to 5990) and 70% (274 to 466), respectively. Gini coefficient of the number of devices was largest for PET and smallest for CT (p for PET-MRI difference geographic distribution of the diagnostic imaging technology in Japan appears to be affected by spatial competition derived from a market force.

  19. Geographic distribution of Staphylococcus aureus causing invasive infections in Europe : A molecular-epidemiological analysis

    NARCIS (Netherlands)

    Grundmann, Hajo; Aanensen, David M; van den Wijngaard, Cees C; Spratt, Brian G; Harmsen, Dag; Friedrich, Alexander W; Tami, Adriana

    Background: Staphylococcus aureus is one of the most important human pathogens and methicillin-resistant variants (MRSAs) are a major cause of hospital and community-acquired infection. We aimed to map the geographic distribution of the dominant clones that cause invasive infections in Europe.

  20. Integration of Geographical Information Systems and Geophysical Applications with Distributed Computing Technologies.

    Science.gov (United States)

    Pierce, M. E.; Aktas, M. S.; Aydin, G.; Fox, G. C.; Gadgil, H.; Sayar, A.

    2005-12-01

    We examine the application of Web Service Architectures and Grid-based distributed computing technologies to geophysics and geo-informatics. We are particularly interested in the integration of Geographical Information System (GIS) services with distributed data mining applications. GIS services provide the general purpose framework for building archival data services, real time streaming data services, and map-based visualization services that may be integrated with data mining and other applications through the use of distributed messaging systems and Web Service orchestration tools. Building upon on our previous work in these areas, we present our current research efforts. These include fundamental investigations into increasing XML-based Web service performance, supporting real time data streams, and integrating GIS mapping tools with audio/video collaboration systems for shared display and annotation.

  1. Effective environmental factors on geographical distribution of traffic accidents on pedestrians, downtown Tehran city.

    Science.gov (United States)

    Moradi, Ali; Soori, Hamid; Kavousi, Amir; Eshghabadi, Farshid; Nematollahi, Shahrzad; Zeini, Salahdien

    2017-01-01

    In most countries, occurrence of traffic causalities is high in pedestrians. The aim of this study is to geographically analyze the traffic casualties in pedestrians in downtown Tehran city. The study population consisted of traffic injury accidents in pedestrians occurred during 2015 in Tehran city. Data were extracted from offices of traffic police and municipality. For analysis of environmental factors and site of accidents, ordinary least square regression models and geographically weighted regression were used. Fitness and performance of models were checked using the Akaike information criteria, Bayesian information criteria, deviance, and adjusted R 2 . Totally, 514 accidents were included in this study. Of them, site of accidents was arterial streets in 370 (71.9%) cases, collector streets in 133 cases (25.2%), and highways in 11 cases (2.1%). Geographical units of traffic accidents in pedestrians had statistically significant relationship with a number of bus stations, number of crossroads, and recreational areas. Distribution of injury traffic accidents in pedestrians is different in downtown Tehran city. Neighborhoods close to markets are considered as most dangerous neighborhoods for injury traffic accidents. Different environmental factors are involved in determining the distribution of these accidents. The health of pedestrians in Tehran city can be improved by proper traffic management, control of environmental factors, and educational programs.

  2. Uncovering the drivers of host-associated microbiota with joint species distribution modelling.

    Science.gov (United States)

    Björk, Johannes R; Hui, Francis K C; O'Hara, Robert B; Montoya, Jose M

    2018-06-01

    In addition to the processes structuring free-living communities, host-associated microbiota are directly or indirectly shaped by the host. Therefore, microbiota data have a hierarchical structure where samples are nested under one or several variables representing host-specific factors, often spanning multiple levels of biological organization. Current statistical methods do not accommodate this hierarchical data structure and therefore cannot explicitly account for the effect of the host in structuring the microbiota. We introduce a novel extension of joint species distribution models (JSDMs) which can straightforwardly accommodate and discern between effects such as host phylogeny and traits, recorded covariates such as diet and collection site, among other ecological processes. Our proposed methodology includes powerful yet familiar outputs seen in community ecology overall, including (a) model-based ordination to visualize and quantify the main patterns in the data; (b) variance partitioning to assess how influential the included host-specific factors are in structuring the microbiota; and (c) co-occurrence networks to visualize microbe-to-microbe associations. © 2018 John Wiley & Sons Ltd.

  3. Towards a theoretical determination of the geographical probability distribution of meteoroid impacts on Earth

    Science.gov (United States)

    Zuluaga, Jorge I.; Sucerquia, Mario

    2018-06-01

    Tunguska and Chelyabinsk impact events occurred inside a geographical area of only 3.4 per cent of the Earth's surface. Although two events hardly constitute a statistically significant demonstration of a geographical pattern of impacts, their spatial coincidence is at least tantalizing. To understand if this concurrence reflects an underlying geographical and/or temporal pattern, we must aim at predicting the spatio-temporal distribution of meteoroid impacts on Earth. For this purpose we designed, implemented, and tested a novel numerical technique, the `Gravitational Ray Tracing' (GRT) designed to compute the relative impact probability (RIP) on the surface of any planet. GRT is inspired by the so-called ray-casting techniques used to render realistic images of complex 3D scenes. In this paper we describe the method and the results of testing it at the time of large impact events. Our findings suggest a non-trivial pattern of impact probabilities at any given time on the Earth. Locations at 60-90° from the apex are more prone to impacts, especially at midnight. Counterintuitively, sites close to apex direction have the lowest RIP, while in the antapex RIP are slightly larger than average. We present here preliminary maps of RIP at the time of Tunguska and Chelyabinsk events and found no evidence of a spatial or temporal pattern, suggesting that their coincidence was fortuitous. We apply the GRT method to compute theoretical RIP at the location and time of 394 large fireballs. Although the predicted spatio-temporal impact distribution matches marginally the observed events, we successfully predict their impact speed distribution.

  4. Genetic Evidence of Contemporary Dispersal of the Intermediate Snail Host of Schistosoma japonicum: Movement of an NTD Host Is Facilitated by Land Use and Landscape Connectivity.

    Science.gov (United States)

    Head, Jennifer R; Chang, Howard; Li, Qunna; Hoover, Christopher M; Wilke, Thomas; Clewing, Catharina; Carlton, Elizabeth J; Liang, Song; Lu, Ding; Zhong, Bo; Remais, Justin V

    2016-12-01

    While the dispersal of hosts and vectors-through active or passive movement-is known to facilitate the spread and re-emergence of certain infectious diseases, little is known about the movement ecology of Oncomelania spp., intermediate snail host of the parasite Schistosoma japonicum, and its consequences for the spread of schistosomiasis in East and Southeast Asia. In China, despite intense control programs aimed at preventing schistosomiasis transmission, there is evidence in recent years of re-emergence and persistence of infection in some areas, as well as an increase in the spatial extent of the snail host. A quantitative understanding of the dispersal characteristics of the intermediate host can provide new insights into the spatial dynamics of transmission, and can assist public health officials in limiting the geographic spread of infection. Oncomelania hupensis robertsoni snails (n = 833) were sampled from 29 sites in Sichuan, China, genotyped, and analyzed using Bayesian assignment to estimate the rate of recent snail migration across sites. Landscape connectivity between each site pair was estimated using the geographic distance distributions derived from nine environmental models: Euclidean, topography, incline, wetness, land use, watershed, stream use, streams and channels, and stream velocity. Among sites, 14.4% to 32.8% of sampled snails were identified as recent migrants, with 20 sites comprising >20% migrants. Migration rates were generally low between sites, but at 8 sites, over 10% of the overall host population originated from one proximal site. Greater landscape connectivity was significantly associated with increased odds of migration, with the minimum path distance (as opposed to median or first quartile) emerging as the strongest predictor across all environmental models. Models accounting for land use explained the largest proportion of the variance in migration rates between sites. A greater number of irrigation channels leading into a

  5. Genetic Evidence of Contemporary Dispersal of the Intermediate Snail Host of Schistosoma japonicum: Movement of an NTD Host Is Facilitated by Land Use and Landscape Connectivity.

    Directory of Open Access Journals (Sweden)

    Jennifer R Head

    2016-12-01

    Full Text Available While the dispersal of hosts and vectors-through active or passive movement-is known to facilitate the spread and re-emergence of certain infectious diseases, little is known about the movement ecology of Oncomelania spp., intermediate snail host of the parasite Schistosoma japonicum, and its consequences for the spread of schistosomiasis in East and Southeast Asia. In China, despite intense control programs aimed at preventing schistosomiasis transmission, there is evidence in recent years of re-emergence and persistence of infection in some areas, as well as an increase in the spatial extent of the snail host. A quantitative understanding of the dispersal characteristics of the intermediate host can provide new insights into the spatial dynamics of transmission, and can assist public health officials in limiting the geographic spread of infection.Oncomelania hupensis robertsoni snails (n = 833 were sampled from 29 sites in Sichuan, China, genotyped, and analyzed using Bayesian assignment to estimate the rate of recent snail migration across sites. Landscape connectivity between each site pair was estimated using the geographic distance distributions derived from nine environmental models: Euclidean, topography, incline, wetness, land use, watershed, stream use, streams and channels, and stream velocity. Among sites, 14.4% to 32.8% of sampled snails were identified as recent migrants, with 20 sites comprising >20% migrants. Migration rates were generally low between sites, but at 8 sites, over 10% of the overall host population originated from one proximal site. Greater landscape connectivity was significantly associated with increased odds of migration, with the minimum path distance (as opposed to median or first quartile emerging as the strongest predictor across all environmental models. Models accounting for land use explained the largest proportion of the variance in migration rates between sites. A greater number of irrigation channels

  6. Response to host volatiles by native and introduced populations of Dendroctonus valens (Coleoptera: Curculionidae, Scolytinae) in North America and China.  Journal of Chemical Ecology 33: 131-146.

    Science.gov (United States)

    N. Erbilgin; S.R. Mori; J.H. Sun; J.D. Stein; D.R. Owen; L.D. Merrill; R. Campos Bolande; os; K.F. Raffa; T. Mendez Montiel; D.L. Wood; N.E.  Gillette

    2007-01-01

    Bark beetles (Coleoptera: Curculionidae, Scolytinae) have specialized feeding habits, and commonly colonize only one or a few closely related host genera in their geographical ranges. The red turpentine beetle, Dendroctonus valens LeConte, has a broad geographic distribution in North America and exploits volatile cues from a wide variety of pines...

  7. Comparison of the geographical distribution of feline immunodeficiency virus and feline leukemia virus infections in the United States of America (2000–2011

    Directory of Open Access Journals (Sweden)

    Chhetri Bimal K

    2013-01-01

    Full Text Available Abstract Background Although feline immunodeficiency virus (FIV and feline leukemia virus (FeLV have similar risk factors and control measures, infection rates have been speculated to vary in geographic distribution over North America. Since both infections are endemic in North America, it was assumed as a working hypothesis that their geographic distributions were similar. Hence, the purpose of this exploratory analysis was to investigate the comparative geographical distribution of both viral infections. Counts of FIV (n=17,108 and FeLV (n=30,017 positive serology results (FIV antibody and FeLV ELISA were obtained for 48 contiguous states and District of Columbia of the United States of America (US from the IDEXX Laboratories website. The proportional morbidity ratio of FIV to FeLV infection was estimated for each administrative region and its geographic distribution pattern was visualized by a choropleth map. Statistical evidence of an excess in the proportional morbidity ratio from unity was assessed using the spatial scan test under the normal probability model. Results This study revealed distinct spatial distribution patterns in the proportional morbidity ratio suggesting the presence of one or more relevant and geographically varying risk factors. The disease map indicates that there is a higher prevalence of FIV infections in the southern and eastern US compared to FeLV. In contrast, FeLV infections were observed to be more frequent in the western US compared to FIV. The respective excess in proportional morbidity ratio was significant with respect to the spatial scan test (p Conclusions The observed variability in the geographical distribution of the proportional morbidity ratio of FIV to FeLV may be related to the presence of an additional or unique, but yet unknown, spatial risk factor. Putative factors may be geographic variations in specific virus strains and rate of vaccination. Knowledge of these factors and the geographical

  8. Global checklist of species of Grania (Clitellata: Enchytraeidae with remarks on their geographic distribution

    Directory of Open Access Journals (Sweden)

    Alessandro Prantoni

    2017-12-01

    Full Text Available A checklist of all currently accepted species of Grania Southern, 1913 (Annelida, Clitellata, Enchytraeidae is presented. The genus is widespread over the world and comprises 81 species described to date. Remarks on their geographical distribution, habitat, synonymies and museum catalogue numbers are provided.

  9. The evolution of cooperation on geographical networks

    Science.gov (United States)

    Li, Yixiao; Wang, Yi; Sheng, Jichuan

    2017-11-01

    We study evolutionary public goods game on geographical networks, i.e., complex networks which are located on a geographical plane. The geographical feature effects in two ways: In one way, the geographically-induced network structure influences the overall evolutionary dynamics, and, in the other way, the geographical length of an edge influences the cost when the two players at the two ends interact. For the latter effect, we design a new cost function of cooperators, which simply assumes that the longer the distance between two players, the higher cost the cooperator(s) of them have to pay. In this study, network substrates are generated by a previous spatial network model with a cost-benefit parameter controlling the network topology. Our simulations show that the greatest promotion of cooperation is achieved in the intermediate regime of the parameter, in which empirical estimates of various railway networks fall. Further, we investigate how the distribution of edges' geographical costs influences the evolutionary dynamics and consider three patterns of the distribution: an approximately-equal distribution, a diverse distribution, and a polarized distribution. For normal geographical networks which are generated using intermediate values of the cost-benefit parameter, a diverse distribution hinders the evolution of cooperation, whereas a polarized distribution lowers the threshold value of the amplification factor for cooperation in public goods game. These results are helpful for understanding the evolution of cooperation on real-world geographical networks.

  10. Growing diversity of trypanosomatid parasites of flies (Diptera: Brachycera): Frequent cosmopolitism and moderate host specificity

    Czech Academy of Sciences Publication Activity Database

    Týč, Jiří; Votýpka, Jan; Klepetková, H.; Šuláková, H.; Jirků, Milan; Lukeš, Julius

    2013-01-01

    Roč. 69, č. 1 (2013), s. 255-264 ISSN 1055-7903 R&D Projects: GA ČR GD206/09/H026 Grant - others:GA AV ČR(CZ) M200961204 Institutional support: RVO:60077344 Keywords : Host specificity * Geographic distribution * Diversity * Phylogeny * Trypanosomatida * Leishmania Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.018, year: 2013

  11. A Virtual Hosting Environment for Distributed Online Gaming

    Science.gov (United States)

    Brossard, David; Prieto Martinez, Juan Luis

    With enterprise boundaries becoming fuzzier, it’s become clear that businesses need to share resources, expose services, and interact in many different ways. In order to achieve such a distribution in a dynamic, flexible, and secure way, we have designed and implemented a virtual hosting environment (VHE) which aims at integrating business services across enterprise boundaries and virtualising the ICT environment within which these services operate in order to exploit economies of scale for the businesses as well as achieve shorter concept-to-market time scales. To illustrate the relevance of the VHE, we have applied it to the online gaming world. Online gaming is an early adopter of distributed computing and more than 30% of gaming developer companies, being aware of the shift, are focusing on developing high performance platforms for the new online trend.

  12. Geographic distribution of phlebotomine sandfly species (Diptera: Psychodidae) in Central-West Brazil

    Science.gov (United States)

    de Almeida, Paulo Silva; de Andrade, Andrey José; Sciamarelli, Alan; Raizer, Josué; Menegatti, Jaqueline Aparecida; Hermes, Sandra Cristina Negreli Moreira; de Carvalho, Maria do Socorro Laurentino; Gurgel-Gonçalves, Rodrigo

    2015-01-01

    This study updates the geographic distributions of phlebotomine species in Central-West Brazil and analyses the climatic factors associated with their occurrence. The data were obtained from the entomology services of the state departments of health in Central-West Brazil, scientific collections and a literature review of articles from 1962-2014. Ecological niche models were produced for sandfly species with more than 20 occurrences using the Maxent algorithm and eight climate variables. In all, 2,803 phlebotomine records for 127 species were analysed. Nyssomyia whitmani, Evandromyia lenti and Lutzomyia longipalpis were the species with the greatest number of records and were present in all the biomes in Central-West Brazil. The models, which were produced for 34 species, indicated that the Cerrado areas in the central and western regions of Central-West Brazil were climatically more suitable to sandflies. The variables with the greatest influence on the models were the temperature in the coldest months and the temperature seasonality. The results show that phlebotomine species in Central-West Brazil have different geographical distribution patterns and that climate conditions in essentially the entire region favour the occurrence of at least one Leishmania vector species, highlighting the need to maintain or intensify vector control and surveillance strategies. PMID:26018450

  13. Behavioral and physiological correlates of the geographic distributions of amphibious sea kraits (Laticauda spp.)

    Science.gov (United States)

    Brischoux, François; Tingley, Reid; Shine, Richard; Lillywhite, Harvey B.

    2013-02-01

    The physiological costs of living in seawater likely influenced the secondary evolutionary transitions to marine life in tetrapods. However, these costs are alleviated for species that commute between the land and the sea, because terrestrial habitats can provide frequent access to fresh water. Here, we investigate how differences in the ecology and physiology of three sea krait species (Laticauda spp.) interact to determine their environmental tolerances and geographic distributions. These three species vary in their relative use of terrestrial versus marine environments, and they display concomitant adaptations to life on land versus at sea. A species with relatively high dehydration rates in seawater (Laticauda colubrina) occupied oceanic areas with low mean salinities, whereas a species with comparatively high rates of transcutaneous evaporative water loss on land (Laticauda semifasciata) occupied regions with low mean temperatures. A third taxon (Laticauda laticaudata) was intermediate in both of these traits, and yet occupied the broadest geographic range. Our results suggest that the abilities of sea kraits to acquire fresh water on land and tolerate dehydration at sea determine their environmental tolerances and geographic distributions. This finding supports the notion that speciation patterns within sea kraits have been driven by interspecific variation in the degree of reliance upon terrestrial versus marine habitats. Future studies could usefully examine the effects of osmotic challenges on diversification rates in other secondarily marine tetrapod species.

  14. Co-occurrence and hybridization of anther-smut pathogens specialized on Dianthus hosts.

    Science.gov (United States)

    Petit, Elsa; Silver, Casey; Cornille, Amandine; Gladieux, Pierre; Rosenthal, Lisa; Bruns, Emily; Yee, Sarah; Antonovics, Janis; Giraud, Tatiana; Hood, Michael E

    2017-04-01

    Host specialization has important consequences for the diversification and ecological interactions of obligate pathogens. The anther-smut disease of natural plant populations, caused by Microbotryum fungi, has been characterized by specialized host-pathogen interactions, which contribute in part to the isolation among these numerous fungal species. This study investigated the molecular variation of Microbotryum pathogens within the geographic and host-specific distributions on wild Dianthus species in southern European Alps. In contrast to prior studies on this pathogen genus, a range of overlapping host specificities was observed for four delineated Microbotryum lineages on Dianthus hosts, and their frequent co-occurrence within single-host populations was quantified at local and regional scales. In addition to potential consequences for direct pathogen competition, the sympatry of Microbotryum lineages led to hybridization between them in many populations, and these admixed genotypes suffered significant meiotic sterility. Therefore, this investigation of the anther-smut fungi reveals how variation in the degrees of host specificity can have major implications for ecological interactions and genetic integrity of differentiated pathogen lineages. © 2017 John Wiley & Sons Ltd.

  15. Geographical Distribution of Trypanosoma cruzi Genotypes in Venezuela

    Science.gov (United States)

    Carrasco, Hernán J.; Segovia, Maikell; Llewellyn, Martin S.; Morocoima, Antonio; Urdaneta-Morales, Servio; Martínez, Cinda; Martínez, Clara E.; Garcia, Carlos; Rodríguez, Marlenes; Espinosa, Raul; de Noya, Belkisyolé A.; Díaz-Bello, Zoraida; Herrera, Leidi; Fitzpatrick, Sinead; Yeo, Matthew; Miles, Michael A.; Feliciangeli, M. Dora

    2012-01-01

    Chagas disease is an endemic zoonosis native to the Americas and is caused by the kinetoplastid protozoan parasite Trypanosoma cruzi. The parasite is also highly genetically diverse, with six discrete typing units (DTUs) reported TcI – TcVI. These DTUs broadly correlate with several epidemiogical, ecological and pathological features of Chagas disease. In this manuscript we report the most comprehensive evaluation to date of the genetic diversity of T. cruzi in Venezuela. The dataset includes 778 samples collected and genotyped over the last twelve years from multiple hosts and vectors, including nine wild and domestic mammalian host species, and seven species of triatomine bug, as well as from human sources. Most isolates (732) can be assigned to the TcI clade (94.1%); 24 to the TcIV group (3.1%) and 22 to TcIII (2.8%). Importantly, among the 95 isolates genotyped from human disease cases, 79% belonged to TcI - a DTU common in the Americas, however, 21% belonged to TcIV- a little known genotype previously thought to be rare in humans. Furthermore, were able to assign multiple oral Chagas diseases cases to TcI in the area around the capital, Caracas. We discuss our findings in the context of T. cruzi DTU distributions elsewhere in the Americas, and evaluate the impact they have on the future of Chagas disease control in Venezuela. PMID:22745843

  16. Historical distribution and host-vector diversity of Francisella tularensis, the causative agent of tularemia, in Ukraine.

    Science.gov (United States)

    Hightower, Jake; Kracalik, Ian T; Vydayko, Nataliya; Goodin, Douglas; Glass, Gregory; Blackburn, Jason K

    2014-10-16

    Francisella tularensis, the causative agent of tularemia, is a zoonotic agent that remains across much of the northern hemisphere, where it exists in enzootic cycles. In Ukraine, tularemia has a long history that suggests a need for sustained surveillance in natural foci. To better characterize the host-vector diversity and spatial distribution of tularemia, we analyzed historical data from field collections carried out from 1941 to 2008. We analyzed the spatial-temporal distribution of bacterial isolates collected from field samples. Isolates were characterized by source and dominant land cover type. To identify environmental persistence and spatial variation in the source of isolation, we used the space-time permutation and multinomial models in SaTScan. A total of 3,086 positive isolates were taken from 1,084 geographic locations. Isolation of F. tularensis was more frequent among arthropods [n = 2,045 (66.3%)] followed by mammals [n = 619 (20.1%)], water [n = 393 (12.7%)], and farm produce [n = 29 (0.94%)], respectively. Four areas of persistent bacterial isolation were identified. Water and farm produce as sources of bacterial isolation were clustered. Our findings confirm the presence of long-standing natural foci of F. tularensis in Ukraine. Given the history of tularemia as well as its environmental persistence there exists a possibility of (re)emergence in human populations. Heterogeneity in the distribution of tularemia isolate recovery related to land cover type supports the theory of natural nidality and clusters identify areas to target potential sources of the pathogen and improve surveillance.

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

    Science.gov (United States)

    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

  18. Virtual Geographic Simulation of Light Distribution within Three-Dimensional Plant Canopy Models

    Directory of Open Access Journals (Sweden)

    Liyu Tang

    2017-12-01

    Full Text Available Virtual geographic environments (VGEs have been regarded as an important new means of simulating, analyzing, and understanding complex geological processes. Plants and light are major components of the geographic environment. Light is a critical factor that affects ecological systems. In this study, we focused on simulating light transmission and distribution within a three-dimensional plant canopy model. A progressive refinement radiosity algorithm was applied to simulate the transmission and distribution of solar light within a detailed, three-dimensional (3D loquat (Eriobotrya japonica Lindl. canopy model. The canopy was described in three dimensions, and each organ surface was represented by a set of triangular facets. The form factors in radiosity were calculated using a hemi-cube algorithm. We developed a module for simulating the instantaneous light distribution within a virtual canopy, which was integrated into ParaTree. We simulated the distribution of photosynthetically active radiation (PAR within a loquat canopy, and calculated the total PAR intercepted at the whole canopy scale, as well as the mean PAR interception per unit leaf area. The ParaTree-integrated radiosity model simulates the uncollided propagation of direct solar and diffuse sky light and the light-scattering effect of foliage. The PAR captured by the whole canopy based on the radiosity is approximately 9.4% greater than that obtained using ray tracing and TURTLE methods. The latter methods do not account for the scattering among leaves in the canopy in the study, and therefore, the difference might be due to the contribution of light scattering in the foliage. The simulation result is close to Myneni’s findings, in which the light scattering within a canopy is less than 10% of the incident PAR. Our method can be employed for visualizing and analyzing the spatial distribution of light within a canopy, and for estimating the PAR interception at the organ and canopy

  19. Geographic distribution of trauma centers and injury-related mortality in the United States.

    Science.gov (United States)

    Brown, Joshua B; Rosengart, Matthew R; Billiar, Timothy R; Peitzman, Andrew B; Sperry, Jason L

    2016-01-01

    Regionalized trauma care improves outcomes; however, access to care is not uniform across the United States. The objective was to evaluate whether geographic distribution of trauma centers correlates with injury mortality across state trauma systems. Level I or II trauma centers in the contiguous United States were mapped. State-level age-adjusted injury fatality rates per 100,000 people were obtained and evaluated for spatial autocorrelation. Nearest neighbor ratios (NNRs) were generated for each state. A NNR less than 1 indicates clustering, while a NNR greater than 1 indicates dispersion. NNRs were tested for difference from random geographic distribution. Fatality rates and NNRs were examined for correlation. Fatality rates were compared between states with trauma center clustering versus dispersion. Trauma center distribution and population density were evaluated. Spatial-lag regression determined the association between fatality rate and NNR, controlling for state-level demographics, population density, injury severity, trauma system resources, and socioeconomic factors. Fatality rates were spatially autocorrelated (Moran's I = 0.35, p center distribution. Fatality rate and NNR were correlated (ρ = 0.34, p = 0.03). Clustered states had a lower median injury fatality rate compared with dispersed states (56.9 [IQR, 46.5-58.9] vs. 64.9 [IQR, 52.5-77.1]; p = 0.04). Dispersed compared with clustered states had more counties without a trauma center that had higher population density than counties with a trauma center (5.7% vs. 1.2%, p distribution of trauma centers correlates with injury mortality, with more clustered state trauma centers associated with lower fatality rates. This may be a result of access relative to population density. These results may have implications for trauma system planning and require further study to investigate underlying mechanisms. Therapeutic/care management study, level IV.

  20. Along for the ride or missing it altogether: exploring the host specificity and diversity of haemogregarines in the Canary Islands.

    Science.gov (United States)

    Tomé, Beatriz; Pereira, Ana; Jorge, Fátima; Carretero, Miguel A; Harris, D James; Perera, Ana

    2018-03-19

    Canary Islands in three colonization events with each host genus; and (iii) the high number of parasite haplotypes infecting Gallotia hosts and their restricted geographical distribution suggest co-diversification. These findings contrast with our expectations derived from results on other insular parasites, highlighting how host specificity depends on parasite characteristics and evolutionary history.

  1. Historical biogeography among species of Varestrongylus lungworms (Nematoda: Protostrongylidae) in ungulates: episodic expansion and host colonization linking Eurasia and North America.

    Science.gov (United States)

    Verocai, Guilherme G; Kutz, Susan J; Hoberg, Eric P

    2018-05-03

    Varestrongylus lungworms (Nematoda: Protostrongylidae) include 10 nominal species that parasitize wild and domesticated artiodactyles. Eight species are endemic to the western Palearctic and Eurasia, whereas two are limited in distribution to the Nearctic. Complex host associations, primarily among Cervidae and Bovidae (Caprinae), and biogeography were explored based on direct comparisons of parasite and host phylogenies to reveal the historical development of this fauna. Diversification among Varestrongylus species has an intricate history extending over the Pliocene and Quaternary involving episodic processes for geographic and host colonization: (1) Varestrongylus has origins in Eurasia with independent expansion events into bordering ecozones; (2) cervids are ancestral hosts; (3) the caprine-associated V. pneumonicus is basal and a result of an independent host colonization event; (4) secondary diversification, linked to sequential and independent host colonization events, occurred within cervids (V. sagittatus + V. tuvae; V. alpenae; and V. capreoli, V. alces + V. eleguneniensis); (5) at least two additional host colonization events into caprines occurred, followed or not by diversification (V. qinghaiensis + V. longispiculatus; V. capricola, respectively); (6) two independent events of geographic expansion into North America from Eurasia with cervids in the late Pliocene and early Pleistocene are postulated (V. alpenae, V. eleguneniensis). Comparisons based on phylogenetic hypotheses derived from comparative morphology and molecular inference for these nematodes are consistent with the postulated history for coevolutionary and biogeographic history. Episodes of geographic and host colonization, often in relation to rapid shifts in climate and habitat perturbation, have dominated the history of diversification of Varestrongylus.

  2. Potential distribution of the endangered endemic lizard Liolaemus lutzae Mertens, 1938 (Liolaemidae: are there other suitable areas for a geographically restricted species?

    Directory of Open Access Journals (Sweden)

    GR. Winck

    Full Text Available In this study we attempted to access further information on the geographical distribution of the endangered lizard Liolaemus lutzae, estimating its potential distribution through the maximum entropy algorithm. For this purpose, we related its points of occurrence with matrices of environmental variables. After examining the correlation between environmental matrices, we selected 10 for model construction. The main variables influencing the current geographic distribution of L. lutzae were the diurnal temperature range and altitude. The species endemism seemed to be a consequence of a reduction of the original distribution area. Alternatively, the resulting model may reflect the geographic distribution of an ancestral lineage, since the model selected areas of occurrence of the two other species of Liolaemus from Brazil (L. arambarensis and L. occipitalis, all living in sand dune habitats and having psamophilic habits. Due to the high loss rate of habitat occupied by the species, the conservation and recovery of the remaining areas affected by human actions is essential.

  3. Effect of Heterogeneity in Initial Geographic Distribution on Opinions’ Competitiveness

    Directory of Open Access Journals (Sweden)

    Alexander S. Balankin

    2015-05-01

    Full Text Available Spin dynamics on networks allows us to understand how a global consensus emerges out of individual opinions. Here, we are interested in the effect of heterogeneity in the initial geographic distribution of a competing opinion on the competitiveness of its own opinion. Accordingly, in this work, we studied the effect of spatial heterogeneity on the majority rule dynamics using a three-state spin model, in which one state is neutral. Monte Carlo simulations were performed on square lattices divided into square blocks (cells. Accordingly, one competing opinion was distributed uniformly among cells, whereas the spatial distribution of the rival opinion was varied from the uniform to heterogeneous, with the median-to-mean ratio in the range from 1 to 0. When the size of discussion group is odd, the uncommitted agents disappear completely after  3.30 ± 0.05 update cycles, and then the system evolves in a two-state regime with complementary spatial distributions of two competing opinions. Even so, the initial heterogeneity in the spatial distribution of one of the competing opinions causes a decrease of this opinion competitiveness. That is, the opinion with initially heterogeneous spatial distribution has less probability to win, than the opinion with the initially uniform spatial distribution, even when the initial concentrations of both opinions are equal. We found that although the time to consensus , the opinion’s recession rate is determined during the first 3.3 update cycles. On the other hand, we found that the initial heterogeneity of the opinion spatial distribution assists the formation of quasi-stable regions, in which this opinion is dominant. The results of Monte Carlo simulations are discussed with regard to the electoral competition of political parties.

  4. Geographic distribution of isolated indigenous societies in Amazonia and the efficacy of indigenous territories.

    Science.gov (United States)

    Kesler, Dylan C; Walker, Robert S

    2015-01-01

    The headwaters of the Amazon Basin harbor most of the world's last indigenous peoples who have limited contact with encroaching colonists. Knowledge of the geographic distribution of these isolated groups is essential to assist with the development of immediate protections for vulnerable indigenous settlements. We used remote sensing to document the locations of 28 isolated villages within the four Brazilian states of Acre, Amazonas, Roraima, and Rondônia. The sites were confirmed during previous over-flights and by image evidence of thatched-roof houses; they are estimated to host over 1,700 individuals. Locational data were used to train maximum entropy models that identified landscape and anthropogenic features associated with the occurrence of isolated indigenous villages, including elevation, proximity to streams of five different orders, proximity to roads and settlements, proximity to recent deforestation, and vegetation cover type. Isolated villages were identified at mid elevations, within 20 km of the tops of watersheds and at greater distances from existing roads and trails. We further used model results, combined with boundaries of the existing indigenous territory system that is designed to protect indigenous lands, to assess the efficacy of the existing protected area network for isolated peoples. Results indicate that existing indigenous territories encompass all of the villages we identified, and 50% of the areas with high predicted probabilities of isolated village occurrence. Our results are intended to help inform policies that can mitigate against future external threats to isolated peoples.

  5. Geographic distribution of isolated indigenous societies in Amazonia and the efficacy of indigenous territories.

    Directory of Open Access Journals (Sweden)

    Dylan C Kesler

    Full Text Available The headwaters of the Amazon Basin harbor most of the world's last indigenous peoples who have limited contact with encroaching colonists. Knowledge of the geographic distribution of these isolated groups is essential to assist with the development of immediate protections for vulnerable indigenous settlements. We used remote sensing to document the locations of 28 isolated villages within the four Brazilian states of Acre, Amazonas, Roraima, and Rondônia. The sites were confirmed during previous over-flights and by image evidence of thatched-roof houses; they are estimated to host over 1,700 individuals. Locational data were used to train maximum entropy models that identified landscape and anthropogenic features associated with the occurrence of isolated indigenous villages, including elevation, proximity to streams of five different orders, proximity to roads and settlements, proximity to recent deforestation, and vegetation cover type. Isolated villages were identified at mid elevations, within 20 km of the tops of watersheds and at greater distances from existing roads and trails. We further used model results, combined with boundaries of the existing indigenous territory system that is designed to protect indigenous lands, to assess the efficacy of the existing protected area network for isolated peoples. Results indicate that existing indigenous territories encompass all of the villages we identified, and 50% of the areas with high predicted probabilities of isolated village occurrence. Our results are intended to help inform policies that can mitigate against future external threats to isolated peoples.

  6. Geographic Distribution of Trauma Centers and Injury Related Mortality in the United States

    Science.gov (United States)

    Brown, Joshua B.; Rosengart, Matthew R.; Billiar, Timothy R.; Peitzman, Andrew B.; Sperry, Jason L.

    2015-01-01

    Background Regionalized trauma care improves outcomes; however access to care is not uniform across the US. The objective was to evaluate whether geographic distribution of trauma centers correlates with injury mortality across state trauma systems. Methods Level I/II trauma centers in the contiguous US were mapped. State-level age-adjusted injury fatality rates/100,000people were obtained and evaluated for spatial autocorrelation. Nearest neighbor ratios (NNR) were generated for each state. A NNR1 indicates dispersion. NNR were tested for difference from random geographic distribution. Fatality rates and NNR were examined for correlation. Fatality rates were compared between states with trauma center clustering versus dispersion. Trauma center distribution and population density were evaluated. Spatial-lag regression determined the association between fatality rate and NNR, controlling for state-level demographics, population density, injury severity, trauma system resources, and socioeconomic factors. Results Fatality rates were spatially autocorrelated (Moran's I=0.35, pcenter distribution. Fatality rate and NNR were correlated (ρ=0.34, p=0.03). Clustered states had a lower median injury fatality rate compared to dispersed states (56.9 [IQR 46.5–58.9] versus 64.9 [IQR 52.5–77.1], p=0.04). Dispersed compared to clustered states had more counties without a trauma center that had higher population density than counties with a trauma center (5.7% versus 1.2%, pdistribution of trauma centers correlates with injury mortality, with more clustered state trauma centers associated with lower fatality rates. This may be a result of access relative to population density. These results may have implications for trauma system planning and requires further study to investigate underlying mechanisms PMID:26517780

  7. Review of the geographic distribution of Micrurus decoratus (Jan, 1858 (Serpentes: Elapidae

    Directory of Open Access Journals (Sweden)

    Rodrigo Castellari Gonzalez

    2014-08-01

    Full Text Available Micrurus decoratus (Jan, 1858 is a poorly known species of coral snake, with a controversial history concerning its geographical range. The lack of consensus among researchers, since its original description, is largely due to the reporting of erroneous localities in publications. Herein we present the geographical range for the species based on the review of 184 records from 67 different municipalities in Brazil, including two new records for the state of Espírito Santo, extending its distribution to ca. 300 km northward from the previous northernmost locality. We also comment on doubtful records for the states of Rio Grande do Sul and Bahia, which contain no accurate data. We restrict the occurrence of Micrurus decoratus to the Atlantic Rainforest, with elevation range from 400 up to 1,600 m in the Brazilian states of Santa Catarina, Paraná, São Paulo, Rio de Janeiro, Minas Gerais and Espírito Santo.

  8. On the geographical distribution of induced time-varying crustal magnetic fields

    DEFF Research Database (Denmark)

    Thebault, E.; Hemant, K.; Hulot, G.

    2009-01-01

    A long standing question in geomagnetism is whether the time variation of the induced crustal field is a detectable quantity and, if so, at which spatial wavelengths. We tackle this problem with the help of a forward modeling approach using a vertically integrated susceptibility (VIS) grid...... of the Earth's crust. For spherical harmonic degrees 15-90, we estimate the root mean square of the crustal magnetic field secular variation to amount 0.06-0.12 nT/yr at the terrestrial surface between epochs 1960-2002.5. The geographical distribution of the signal shows absolute values reaching 0.65-1.30 n...

  9. Geographic distribution of suicide and railway suicide in Belgium, 2008-2013: a principal component analysis.

    Science.gov (United States)

    Strale, Mathieu; Krysinska, Karolina; Overmeiren, Gaëtan Van; Andriessen, Karl

    2017-06-01

    This study investigated the geographic distribution of suicide and railway suicide in Belgium over 2008--2013 on local (i.e., district or arrondissement) level. There were differences in the regional distribution of suicide and railway suicides in Belgium over the study period. Principal component analysis identified three groups of correlations among population variables and socio-economic indicators, such as population density, unemployment, and age group distribution, on two components that helped explaining the variance of railway suicide at a local (arrondissement) level. This information is of particular importance to prevent suicides in high-risk areas on the Belgian railway network.

  10. The geographic distribution patterns of HIV-, HCV- and co-infections among drug users in a national methadone maintenance treatment program in Southwest China.

    Science.gov (United States)

    Zhou, Yi-Biao; Liang, Song; Wang, Qi-Xing; Gong, Yu-Han; Nie, Shi-Jiao; Nan, Lei; Yang, Ai-Hui; Liao, Qiang; Song, Xiu-Xia; Jiang, Qing-Wu

    2014-03-10

    HIV-, HCV- and HIV/HCV co-infections among drug users have become a rapidly emerging global public health problem. In order to constrain the dual epidemics of HIV/AIDS and drug use, China has adopted a methadone maintenance treatment program (MMTP) since 2004. Studies of the geographic heterogeneity of HIV and HCV infections at a local scale are sparse, which has critical implications for future MMTP implementation and health policies covering both HIV and HCV prevention among drug users in China. This study aimed to characterize geographic patterns of HIV and HCV prevalence at the township level among drug users in a Yi Autonomous Prefecture, Southwest of China. Data on demographic and clinical characteristics of all clients in the 11 MMTP clinics of the Yi Autonomous Prefecture from March 2004 to December 2012 were collected. A GIS-based geographic analysis involving geographic autocorrelation analysis and geographic scan statistics were employed to identify the geographic distribution pattern of HIV-, HCV- and co-infections among drug users. A total of 6690 MMTP clients was analyzed. The prevalence of HIV-, HCV- and co-infections were 25.2%, 30.8%, and 10.9% respectively. There were significant global and local geographic autocorrelations for HIV-, HCV-, and co-infection. The Moran's I was 0.3015, 0.3449, and 0.3155, respectively (P geographic autocorrelation analysis and the geographic scan statistical analysis showed that HIV-, HCV-, and co-infections in the prefecture exhibited significant geographic clustering at the township level. The geographic distribution pattern of each infection group was different. HIV-, HCV-, and co-infections among drug users in the Yi Autonomous Prefecture all exhibited substantial geographic heterogeneity at the township level. The geographic distribution patterns of the three groups were different. These findings imply that it may be necessary to inform or invent site-specific intervention strategies to better devote currently

  11. THE OPTICALLY UNBIASED GRB HOST (TOUGH) SURVEY. III. REDSHIFT DISTRIBUTION

    Energy Technology Data Exchange (ETDEWEB)

    Jakobsson, P.; Chapman, R.; Vreeswijk, P. M. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik (Iceland); Hjorth, J.; Malesani, D.; Fynbo, J. P. U.; Milvang-Jensen, B. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen (Denmark); Tanvir, N. R.; Starling, R. L. C. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Letawe, G. [Departement d' Astrophysique, Geophysique et Oceanographie, ULg, Allee du 6 aout, 17-Bat. B5c B-4000 Liege (Sart-Tilman) (Belgium)

    2012-06-10

    We present 10 new gamma-ray burst (GRB) redshifts and another five redshift limits based on host galaxy spectroscopy obtained as part of a large program conducted at the Very Large Telescope (VLT). The redshifts span the range 0.345 {<=} z {approx}< 2.54. Three of our measurements revise incorrect values from the literature. The homogeneous host sample researched here consists of 69 hosts that originally had a redshift completeness of 55% (with 38 out of 69 hosts having redshifts considered secure). Our project, including VLT/X-shooter observations reported elsewhere, increases this fraction to 77% (53/69), making the survey the most comprehensive in terms of redshift completeness of any sample to the full Swift depth, analyzed to date. We present the cumulative redshift distribution and derive a conservative, yet small, associated uncertainty. We constrain the fraction of Swift GRBs at high redshift to a maximum of 14% (5%) for z > 6 (z > 7). The mean redshift of the host sample is assessed to be (z) {approx}> 2.2, with the 10 new redshifts reducing it significantly. Using this more complete sample, we confirm previous findings that the GRB rate at high redshift (z {approx}> 3) appears to be in excess of predictions based on assumptions that it should follow conventional determinations of the star formation history of the universe, combined with an estimate of its likely metallicity dependence. This suggests that either star formation at high redshifts has been significantly underestimated, for example, due to a dominant contribution from faint, undetected galaxies, or that GRB production is enhanced in the conditions of early star formation, beyond that usually ascribed to lower metallicity.

  12. Geographical distribution and eco-adaptability of calligonum l. in tarim basin

    International Nuclear Information System (INIS)

    Liu, N.; Guan, K.; Feng, Y.

    2017-01-01

    Global climate fluctuations have profoundly affected the current distribution patterns and created opportunities and challenges for the survival and development of species. Studies on geographical distribution and eco-adaptability are necessary for both biodiversity conservation and sustainable biological resource utilization. In this study, we focus on five species of Calligonum in Tarim Basin, i.e. Calligonum roborovskii, C. kurlaense, C. yengisaricum, C. juochiangense and C. taklimakanense to confirm the distribution range by carrying out field population survey, along with the studies of herbarium specimen and relevant literature and also to find out the associations between the five species, distribution correlated with climate and soil characteristics through the mean variance analysis and principal component analysis. The results of the study were as follows: (1) C. roborovskii was widely distributed in Tarim Basin, but C. kurlaense, C. yengisaricum, C. juochiangense and C. taklimakanense have narrow distribution. The distribution areas of four latter species were overlapping with that of C. roborovskii showing sympatric distribution. (2) All the five species belonged to the warm and arid zone. The adaptability of C. roborovskii to moisture was higher, that of C. juochiangense and C. taklimakanense which grew in more arid areas than that of C. kurlaense and C. yengisaricum, had stronger drought tolerance. The soil type of the five species main was brown desert soil with high salinity, alkaline, and low content of organic matter in the top soil. (3) Low temperature, moisture factor, salinity and alkalinity were the main reasons leading to the different distribution of the four narrow distributed species. (4) The main factors limiting the distribution range of the five species were high temperature and moisture factor, followed by soil properties. For C. juochiangense and C. taklimakanense, moisture factor was much stronger than temperature. The results of the

  13. The geographic distribution of the otolaryngology workforce in the United States.

    Science.gov (United States)

    Lango, Miriam N; Handorf, Elizabeth; Arjmand, Ellis

    2017-01-01

    To describe the deployment of otolaryngologists and evaluate factors associated with the geographic distribution of otolaryngologists in the United States. Cross-sectional study. The otolaryngology physician supply was defined as the number of otolaryngologists per 100,000 in the hospital referral region (HRR). The otolaryngology physician supply was derived from the American Medical Association Masterfile or from the Medicare Enrollment and Provider Utilization Files. Multiple linear regression tested the association of population, physician, and hospital factors on the supply of Medicare-enrolled otolaryngologists/HRR. Two methods of measuring the otolaryngology workforce were moderately correlated across hospital referral regions (Pearson coefficient 0.513, P = .0001); regardless, the supply of otolaryngology providers varies greatly over different geographic regions. Otolaryngologists concentrate in regions with many other physicians, particularly specialist physicians. The otolaryngology supply also increases with regional population income and education levels. Using AMA-derived data, there was no association between the supply of otolaryngologists and staffed acute-care hospital beds and the presence of an otolaryngology residency-training program. In contrast, the supply of otolaryngology providers enrolled in Medicare independently increases for each HRR by 0.8 per 100,000 for each unit increase in supply of hospital beds (P otolaryngology residency-training program (P = .006), accounting for all other factors. Irrespective of methodology, the supply of otolaryngologists varies widely across geographic regions in the United States. For Medicare beneficiaries, regional hospital factors-including the presence of an otolaryngology residency program-may improve access to otolaryngology services. NA Laryngoscope, 127:95-101, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

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

    Science.gov (United States)

    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.

  15. Host generalists and specialists emerging side by side: an analysis of evolutionary patterns in the cosmopolitan chewing louse genus Menacanthus

    Czech Academy of Sciences Publication Activity Database

    Martinů, Jana; Sychra, O.; Literák, I.; Čapek, Miroslav; Gustafsson, D. L.; Štefka, Jan

    2015-01-01

    Roč. 45, č. 1 (2015), s. 63-73 ISSN 0020-7519 R&D Projects: GA AV ČR IAA601690901 Institutional support: RVO:60077344 ; RVO:68081766 Keywords : Host specificity * Specialist * Generalist * Population structure * Geographic distribution * Menacanthus Subject RIV: EG - Zoology; EG - Zoology (UBO-W) Impact factor: 4.242, year: 2015

  16. Distributed system for parallel data processing of ECT signals for electromagnetic flaw detection in materials

    International Nuclear Information System (INIS)

    Guliashki, Vassil; Marinova, Galia

    2002-01-01

    The paper proposes a distributed system for parallel data processing of ECT signals for flaw detection in materials. The measured data are stored in files on a host computer, where a JAVA server is located. The host computer is connected through Internet to a set of client computers, distributed geographically. The data are distributed from the host computer by means of the JAVA server to the client computers according their requests. The software necessary for the data processing is installed on each client computer in advance. The organization of the data processing on many computers, working simultaneously in parallel, leads to great time reducing, especially in cases when huge amount of data should be processed in very short time. (Author)

  17. Geographical variation in larval host-plant use by Heliconius erato (Lepidoptera: Nymphalidae and consequences for adult life history

    Directory of Open Access Journals (Sweden)

    RODRIGUES D.

    2002-01-01

    Full Text Available Adult body size, one of the most important life-history components, varies strongly within and between Heliconius erato phyllis (Lepidoptera: Nymphalidae populations. This study determines if this variation is caused by geographical changes in host-plant used by the larval stage, whose reproductive parameters are influenced by female body size, with estimates of the corresponding heritability. The variation in adult body size was determined together with a survey of passion vine species (Passifloraceae used by the larvae in seven localities in Rio Grande do Sul State: three located in the urban area of Porto Alegre and Triunfo Counties, two within Eucalyptus plantations (Barba Negra Forest, Barra do Ribeiro County, and Águas Belas Experimental Station -- Viamão County, one in a Myrtaceae Forest (Itapuã State Park -- Itapuã County and one in the Atlantic Rain Forest (Maquiné Experimental Station -- Maquiné County. Effects of female body size on fecundity, egg size and egg viability were determined in an outdoor insectary. Size heritability was estimated by rearing in the laboratory offspring of individuals maintained in an insectary. The data showed that adults from populations where larvae feed only upon Passiflora suberosa are smaller than those that feed on Passiflora misera. The larvae prefer P. misera even when the dominant passion vine in a given place is P. suberosa. Fecundity increases linearly with the increase in size of females, but there is no size effect on egg size or viability. Size heritability is null for the adult size range occurring in the field. Thus, the geographical variation of H. erato phyllis adult size is primarily determined by the type, corresponding availability and quality of host-plants used by the larval stage. Within the natural size range of H. erato phyllis, the variation related to this caracter is not genetically based, thus being part of H. erato phyllis phenotypic plasticity.

  18. Orobanche pallidiflora Wimm. & Grab. in Poland: distribution, habitat and host preferences

    Directory of Open Access Journals (Sweden)

    Renata Piwowarczyk

    2011-01-01

    Full Text Available The paper presents ten new localities of Orobanche pallidiflora Wimm. & Grab. from Poland (Middle Roztocze, Równina Bełska plain, Wyżyna Malopolska upland, Góry Kaczawskie Mts and Western Bieszczady Mts. Information on hosts, abundance and habitat preferences at the new localities is given and a supplemented map of the distribution in Poland is included.

  19. Geographic distribution of ebony leaf monkey Trachypithecus auratus (E. Geoffroy Saint-Hilaire, 1812) (Mammalia: Primates: Cercopithecidae)

    NARCIS (Netherlands)

    Nijman, Vincent

    2000-01-01

    As one of the fundamental units of ecology and biogeography, the geographic distribution of the endemic and threatened ebony leaf monkey Trachypithecus auratus (E. Geoffroy Saint-Hilaire, 1812) on the islands of Java, Bali, and Lombok (Indonesia) has been assessed. All localities where the species

  20. Evolutionary transitions in symbioses: dramatic reductions in bathymetric and geographic ranges of Zoanthidea coincide with loss of symbioses with invertebrates.

    Science.gov (United States)

    Swain, Timothy D

    2010-06-01

    Two fundamental symbiosis-based trophic types are recognized among Zoanthidea (Cnidaria, Anthozoa): fixed carbon is either obtained directly from zooxanthellae photosymbionts or from environmental sources through feeding with the assistance of host-invertebrate behaviour and structure. Each trophic type is characteristic of the suborders of Zoanthidea and is associated with substantial distributional asymmetries: suborder Macrocnemina are symbionts of invertebrates and have global geographic and bathymetric distributions and suborder Brachycnemina are hosts of endosymbiotic zooxanthellae and are restricted to tropical photic zones. While exposure to solar radiation could explain the bathymetric asymmetry it does not explain the geographic asymmetry, nor is it clear why evolutionary transitions to the zooxanthellae-free state have apparently occurred within Macrocnemina but not within Brachycnemina. To better understand the transitions between symbiosis-based trophic types of Zoanthidea, a concatenated data set of nuclear and mitochondrial nucleotide sequences were used to test hypotheses of monophyly for groups defined by morphology and symbiosis, and to reconstruct the evolutionary transitions of morphological and symbiotic characters. The results indicate that the morphological characters that define Macrocnemina are plesiomorphic and the characters that define its subordinate taxa are homoplasious. Symbioses with invertebrates have ancient and recent transitions with a general pattern of stability in host associations through evolutionary time. The reduction in distribution of Zoanthidea is independent of the evolution of zooxanthellae symbiosis and consistent with hypotheses of the benefits of invertebrate symbioses, indicating that the ability to persist in most habitats may have been lost with the termination of symbioses with invertebrates.

  1. Geographically distributed hybrid testing & collaboration between geotechnical centrifuge and structures laboratories

    Science.gov (United States)

    Ojaghi, Mobin; Martínez, Ignacio Lamata; Dietz, Matt S.; Williams, Martin S.; Blakeborough, Anthony; Crewe, Adam J.; Taylor, Colin A.; Madabhushi, S. P. Gopal; Haigh, Stuart K.

    2018-01-01

    Distributed Hybrid Testing (DHT) is an experimental technique designed to capitalise on advances in modern networking infrastructure to overcome traditional laboratory capacity limitations. By coupling the heterogeneous test apparatus and computational resources of geographically distributed laboratories, DHT provides the means to take on complex, multi-disciplinary challenges with new forms of communication and collaboration. To introduce the opportunity and practicability afforded by DHT, here an exemplar multi-site test is addressed in which a dedicated fibre network and suite of custom software is used to connect the geotechnical centrifuge at the University of Cambridge with a variety of structural dynamics loading apparatus at the University of Oxford and the University of Bristol. While centrifuge time-scaling prevents real-time rates of loading in this test, such experiments may be used to gain valuable insights into physical phenomena, test procedure and accuracy. These and other related experiments have led to the development of the real-time DHT technique and the creation of a flexible framework that aims to facilitate future distributed tests within the UK and beyond. As a further example, a real-time DHT experiment between structural labs using this framework for testing across the Internet is also presented.

  2. The bioclimatic envelope of the wolverine (Gulo gulo): do climatic constraints limit its geographic distribution?

    Science.gov (United States)

    J. P. Copeland; K. S. McKelvey; K. B. Aubry; A. Landa; J. Persson; R. M. Inman; J. Krebs; E. Lofroth; H. Golden; J. R. Squires; A. Magoun; M. K. Schwartz; J. Wilmot; C. L. Copeland; R. E. Yates; I. Kojola; R. May

    2010-01-01

    We propose a fundamental geographic distribution for the wolverine (Gulo gulo (L., 1758)) based on the hypothesis that the occurrence of wolverines is constrained by their obligate association with persistent spring snow cover for successful reproductive denning and by an upper limit of thermoneutrality. To investigate this hypothesis, we developed a composite of MODIS...

  3. Geographic distribution of Staphylococcus aureus causing invasive infections in Europe: a molecular-epidemiological analysis.

    Directory of Open Access Journals (Sweden)

    Hajo Grundmann

    2010-01-01

    Full Text Available Staphylococcus aureus is one of the most important human pathogens and methicillin-resistant variants (MRSAs are a major cause of hospital and community-acquired infection. We aimed to map the geographic distribution of the dominant clones that cause invasive infections in Europe.In each country, staphylococcal reference laboratories secured the participation of a sufficient number of hospital laboratories to achieve national geo-demographic representation. Participating laboratories collected successive methicillin-susceptible (MSSA and MRSA isolates from patients with invasive S. aureus infection using an agreed protocol. All isolates were sent to the respective national reference laboratories and characterised by quality-controlled sequence typing of the variable region of the staphylococcal spa gene (spa typing, and data were uploaded to a central database. Relevant genetic and phenotypic information was assembled for interactive interrogation by a purpose-built Web-based mapping application. Between September 2006 and February 2007, 357 laboratories serving 450 hospitals in 26 countries collected 2,890 MSSA and MRSA isolates from patients with invasive S. aureus infection. A wide geographical distribution of spa types was found with some prevalent in all European countries. MSSA were more diverse than MRSA. Genetic diversity of MRSA differed considerably between countries with dominant MRSA spa types forming distinctive geographical clusters. We provide evidence that a network approach consisting of decentralised typing and visualisation of aggregated data using an interactive mapping tool can provide important information on the dynamics of MRSA populations such as early signalling of emerging strains, cross border spread, and importation by travel.In contrast to MSSA, MRSA spa types have a predominantly regional distribution in Europe. This finding is indicative of the selection and spread of a limited number of clones within health care

  4. Zika virus, vectors, reservoirs, amplifying hosts, and their potential to spread worldwide: what we know and what we should investigate urgently

    Directory of Open Access Journals (Sweden)

    Rengina Vorou

    2016-07-01

    Conclusions: It is a public health imperative to define the domestic and wild animal reservoirs, amplification hosts, and vector capacity of the genera Aedes, Anopheles, and Mansonia. These variables will define the geographic distribution of Zika virus along with the indicated timing and scale of the environmental public health interventions worldwide.

  5. Climate change may alter breeding ground distributions of eastern migratory monarchs (Danaus plexippus) via range expansion of Asclepias host plants.

    Science.gov (United States)

    Lemoine, Nathan P

    2015-01-01

    Climate change can profoundly alter species' distributions due to changes in temperature, precipitation, or seasonality. Migratory monarch butterflies (Danaus plexippus) may be particularly susceptible to climate-driven changes in host plant abundance or reduced overwintering habitat. For example, climate change may significantly reduce the availability of overwintering habitat by restricting the amount of area with suitable microclimate conditions. However, potential effects of climate change on monarch northward migrations remain largely unknown, particularly with respect to their milkweed (Asclepias spp.) host plants. Given that monarchs largely depend on the genus Asclepias as larval host plants, the effects of climate change on monarch northward migrations will most likely be mediated by climate change effects on Asclepias. Here, I used MaxEnt species distribution modeling to assess potential changes in Asclepias and monarch distributions under moderate and severe climate change scenarios. First, Asclepias distributions were projected to extend northward throughout much of Canada despite considerable variability in the environmental drivers of each individual species. Second, Asclepias distributions were an important predictor of current monarch distributions, indicating that monarchs may be constrained as much by the availability of Asclepias host plants as environmental variables per se. Accordingly, modeling future distributions of monarchs, and indeed any tightly coupled plant-insect system, should incorporate the effects of climate change on host plant distributions. Finally, MaxEnt predictions of Asclepias and monarch distributions were remarkably consistent among general circulation models. Nearly all models predicted that the current monarch summer breeding range will become slightly less suitable for Asclepias and monarchs in the future. Asclepias, and consequently monarchs, should therefore undergo expanded northern range limits in summer months

  6. Distribution and habitats of the snail Lymnaea truncatula, intermediate host of the liver fluke Fasciola hepatica, in South Africa

    Directory of Open Access Journals (Sweden)

    K.N. de Kock

    2003-07-01

    Full Text Available This paper focuses on the geographical distribution and habitats of Lymnaea truncatula, the intermediate, snail host of the liver fluke, Fasciola hepatica, as reflected by the 723 samples in the database of the National Freshwater Snail Collection, Potchefstroom, South Africa. The 221 different loci (1/16-degree squares on record reflect an extensive but discontinuous distribution, except in Lesotho and in parts of the Mpumalanga, Gauteng and North West provinces of South Africa. Although recorded from 12 different types of waterbody, it was mostly (42.0 % recovered from swamps. Most samples (45.8 % were collected in habitats with slow-flowing water. A muddy substratum was recorded for 62.5 % of the samples. Most samples (86.3 % were collected in habitats with a mean annual air temperature of 10-20 o C, and more than 69 % came from localities with a mean annual rainfall of 600-900mm. An integrated decision tree constructed from the data indicated that temperature and types of waterbody play a decisive role in determining the presence of L. truncatula in a given area. A temperature index calculated for all mollusc species ranked L. truncatula second in a total of 53 species according to its association with low temperatures. It remains to be established whether its distribution is indeed discontinuous, and whether its preference for a particular habitat, amphibious habits and ability to aestivate could have resulted in some populations having been overlooked during surveys.

  7. BUILDING A GEOGRAPHIC DATA REPOSITORY FOR URBAN RESEARCH WITH FREE SOFTWARE – LEARNING FROM Observatorio.CEDEUS.cl

    Directory of Open Access Journals (Sweden)

    S. Steiniger

    2017-07-01

    Full Text Available The recent trend towards open data and open science as well as a demand for holistic and interdisciplinary research requires platforms that allow the distribution and exchange of research data, including geographic information. While the requirements and benefits of data exchange are widely discussed, there are few proposals on how to implement data platforms that not only permit the exchange of research data among researchers, but also permit to distribute research results and data to the interest public. We elaborate what points are important for implementing a (geographic data repository and propose then to adopt the concept of Spatial Data Infrastructures (SDI as a solution for the implementation of research data repositories. We present as a case study the geographic data and document repository of the Chilean research Centre on Sustainable Urban Development (CEDEUS, the CEDEUS Observatory. Besides the infrastructure to host and distribute data, communication tools are an important component of such a data repository service. For this case study we analyse which things have worked well and which things have not worked well based on the experiences collected during three years of operation. We close with some recommendations for the implementation of data repositories for research.

  8. Modeling The GRB Host Galaxy Mass Distribution: Are GRBs Unbiased Tracers of Star Formation?

    Energy Technology Data Exchange (ETDEWEB)

    Kocevski, Daniel; /KIPAC, Menlo Park; West, Andrew A.; /UC, Berkeley, Astron. Dept. /MIT, MKI; Modjaz, Maryam; /UC, Berkeley, Astron. Dept.

    2009-08-03

    We model the mass distribution of long gamma-ray burst (GRB) host galaxies given recent results suggesting that GRBs occur in low metallicity environments. By utilizing measurements of the redshift evolution of the mass-metallicity (M-Z) relationship for galaxies, along with a sharp host metallicity cut-off suggested by Modjaz and collaborators, we estimate an upper limit on the stellar mass of a galaxy that can efficiently produce a GRB as a function of redshift. By employing consistent abundance indicators, we find that sub-solar metallicity cut-offs effectively limit GRBs to low stellar mass spirals and dwarf galaxies at low redshift. At higher redshifts, as the average metallicity of galaxies in the Universe falls, the mass range of galaxies capable of hosting a GRB broadens, with an upper bound approaching the mass of even the largest spiral galaxies. We compare these predicted limits to the growing number of published GRB host masses and find that extremely low metallicity cut-offs of 0.1 to 0.5 Z{sub {circle_dot}} are effectively ruled out by a large number of intermediate mass galaxies at low redshift. A mass function that includes a smooth decrease in the efficiency of producing GRBs in galaxies of metallicity above 12+log(O/H){sub KK04} = 8.7 can, however, accommodate a majority of the measured host galaxy masses. We find that at z {approx} 1, the peak in the observed GRB host mass distribution is inconsistent with the expected peak in the mass of galaxies harboring most of the star formation. This suggests that GRBs are metallicity biased tracers of star formation at low and intermediate redshifts, although our model predicts that this bias should disappear at higher redshifts due to the evolving metallicity content of the universe.

  9. MODELING THE GRB HOST GALAXY MASS DISTRIBUTION: ARE GRBs UNBIASED TRACERS OF STAR FORMATION?

    International Nuclear Information System (INIS)

    Kocevski, Daniel; West, Andrew A.; Modjaz, Maryam

    2009-01-01

    We model the mass distribution of long gamma-ray burst (GRB) host galaxies given recent results suggesting that GRBs occur in low-metallicity environments. By utilizing measurements of the redshift evolution of the mass-metallicity relationship for galaxies, along with a sharp host metallicity cutoff suggested by Modjaz and collaborators, we estimate an upper limit on the stellar mass of a galaxy that can efficiently produce a GRB as a function of redshift. By employing consistent abundance indicators, we find that subsolar metallicity cutoffs effectively limit GRBs to low-stellar mass spirals and dwarf galaxies at low redshift. At higher redshifts, as the average metallicity of galaxies in the Universe falls, the mass range of galaxies capable of hosting a GRB broadens, with an upper bound approaching the mass of even the largest spiral galaxies. We compare these predicted limits to the growing number of published GRB host masses and find that extremely low-metallicity cutoffs of 0.1 to 0.5 Z sun are effectively ruled out by a large number of intermediate mass galaxies at low redshift. A mass function that includes a smooth decrease in the efficiency of producing GRBs in galaxies of metallicity above 12+log(O/H) KK04 = 8.7 can, however, accommodate a majority of the measured host galaxy masses. We find that at z ∼ 1, the peak in the observed GRB host mass distribution is inconsistent with the expected peak in the mass of galaxies harboring most of the star formation. This suggests that GRBs are metallicity-biased tracers of star formation at low and intermediate redshifts, although our model predicts that this bias should disappear at higher redshifts due to the evolving metallicity content of the universe.

  10. Indoor radon concentration data: Its geographic and geologic distribution, an example from the Capital District, NY

    International Nuclear Information System (INIS)

    Thomas, J.J.; Overeynder, H.M.; Thomas, B.R.

    1995-01-01

    Most studies of the geographic distribution of indoor radon levels are plotted by county or ZIP code. This method is used for the radon potential maps produced by the U.S. Environmental Protection Agency (EPA) and the New York State Department of Health (NYSDOH). The basis for the mapping is the mean or median indoor radon count for all the data provided by NYSDOH within each geographic area. While testing the indoor radon analyses provided to the authors by CMT Independent Laboratories, we discovered data that deviated markedly from the EPA and NYSDOH means for the Capital District of New York (Albany and surrounding counties). Their screening indoor radon average concentrations in pCi/L, indicate low potential for Schenectady (3.0), Saratoga (3.2), and Albany (3.7) counties; and moderate potential for Rensselaer (6.4) and Columbia (7.0) counties. Our database of over 3,000 analyses contains over 800 records of indoor radon counts above 4 pCi/L (14-47% of each county's analyses), many high enough to be rated as a serious health hazard. In order to obtain greater precision of information, the authors plotted their indoor radon data by street address using MapInfo, a geographic Information System (GIS), and StreetInfo, MapInfo's TIGER address database. We compared the geographic distribution of our data to both the Bedrock Geology and Surficial Geology Maps of New York State. The results show a striking relationship of radon concentrations to bedrock, faults and permeability of surficial material. Data being compiled and mapped by street address by the NYSDOH in Erie County in western New York, confirm our results

  11. Geographic distribution and clinical description of leishmaniasis cases in Peru.

    Science.gov (United States)

    Lucas, C M; Franke, E D; Cachay, M I; Tejada, A; Cruz, M E; Kreutzer, R D; Barker, D C; McCann, S H; Watts, D M

    1998-08-01

    Studies were conducted from 1986 through 1993 to further define the geographic distribution and relative importance of different species of Leishmania as a cause of leishmaniasis in Peru. Patients with a clinical diagnosis of cutaneous and/or mucosal or diffuse cutaneous leishmaniasis were enrolled at the Naval Medical Research Institute Detachment (NAMRID) Laboratory in Lima, the Tropical Disease Clinic at San Marcos University Daniel A. Carrión, the Central Military Hospital, and a Ministry of Health hospital in Cusco, Peru. Clinical features, lesion aspirates, and biopsy tissue were obtained from each patient. All specimens were collected and assayed separately, including multiple specimens from some of the same patients for Leishmania parasites by inoculating aliquots of either aspirates or biopsy tissue suspensions onto Senekji's blood agar medium. Stocks of Leishmania isolates were used to prepare promastigotes to produce extracts for identifying the Leishmania species by the cellulose acetate electrophoresis enzyme technique. A total of 351 isolates of Leishmania were obtained from 350 patients who were infected primarily in the low and high jungle of at least 15 different Departments of Peru. Of the 351 isolates, 79% were identified as L. (V.) braziliensis, 7% as L. (V.) guyanensis, 10% as L. (V.) peruviana, 2% as L. (V.) lainsoni, and 1.7% as L. (L.) amazonensis. The clinical form of disease varied depending on the species of Leishmania, with L. (V.) braziliensis being associated most frequently with cutaneous, mucosal ulcers and mixed cutaneous and mucosal disease, and L. (V) peruviana, L. (V.) guyanensis, L. (V.) lainsoni with cutaneous lesions. Leishmania (L.) amazonensis was isolated from six patients, three with cutaneous lesions, one with mucosal lesions, and two with diffuse cutaneous lesions. Among all of the leishmaniasis cases, males were affected more frequently, and cases occurred among patients less than 10 to more than 51 years of age. These

  12. Geographic distribution of Aedes aegypti and Aedes albopictus collected from used tires in Vietnam.

    Science.gov (United States)

    Higa, Yukiko; Yen, Nguyen Thi; Kawada, Hitoshi; Son, Tran Hai; Hoa, Nguyen Thuy; Takagi, Masahiro

    2010-03-01

    The spatial distribution of Aedes aegypti and Aedes albopictus in environmental and geographical zones, e.g., urban-rural, coastal-mountainous, and north-south, was investigated throughout Vietnam. Immature stages were collected from used tires along roads. The effects of regions, seasons, and the degree of urbanization on the density and the frequency were statistically analyzed. Aedes aegypti predominated in the southern and central regions, while Ae. albopictus predominated in the northern region, which may be related to climatic conditions (temperature and rainfall). Larval collection from used tires may be suitable to assess rapidly the current distribution of dengue mosquitoes for estimating health risks and implementing vector control measures.

  13. Using rare earth elements for the identification of the geographic origin of food

    Science.gov (United States)

    Meisel, T.; Bandoniene, D.; Joebstl, D.

    2009-04-01

    The European Union defined regimes within the Protected Geographical Status (PGS) framework to protect names of regional food specialities. Thus only food produced in a specific geographical area with a specific way of production or quality can be protected by a protected geographical indication (PGI) label. As such Styrian Pumpkin Seed Oil has been approved with this label, but as with many other high priced regional specialities, fraud cannot be excluded or nor identified. Thus the aim of this work is, to develop an analytical method for the control of the geographic origin of pumpkin seed oil and also to test the method for other protected products. The development of such a method is not only of interest for scientists, but also of importance for the consumer wanting to know the origin of the food products and the assurance of the purity and quality. The group of rare earth elements (REE) in plants also have a characteristic distribution pattern similar to upper crustal REE distributions. Since the REE concentrations are extremely low in pumpkin seed oil (ppt to low ppb), ICP-MS was the only sensitive tool able to produce validated results. The carrier of the REE are most likely small particles distributed within the pumpkin seed oil. Unlike, e.g., olive oil, pumpkin seed oil is bottled and sold unfiltered, which makes this Styrian speciality an interesting sampling target. As pumpkin seed oils from different geographic origin show variable trace element and rare earth distribution patterns, is should possible to trace the origin of these oils. In the current project pumpkin seeds from different regions in Austria and from abroad were sampled. The trace element patterns in the extracted oil of these seeds were determined and a preliminary classification with discriminate analysis was successfully done on a statistical basis. In addition to the study of the geographic origin it was demonstrated that REE distribution patterns can also be used for the

  14. Mapping and Modelling the Geographical Distribution and Environmental Limits of Podoconiosis in Ethiopia

    OpenAIRE

    Deribe, Kebede; Cano, Jorge; Newport, Melanie J.; Golding, Nick; Pullan, Rachel L.; Sime, Heven; Gebretsadik, Abeba; Assefa, Ashenafi; Kebede, Amha; Hailu, Asrat; Rebollo, Maria P.; Shafi, Oumer; Bockarie, Moses J.; Aseffa, Abraham; Hay, Simon I.

    2015-01-01

    Background\\ud \\ud Ethiopia is assumed to have the highest burden of podoconiosis globally, but the geographical distribution and environmental limits and correlates are yet to be fully investigated. In this paper we use data from a nationwide survey to address these issues.\\ud \\ud Methodology\\ud \\ud Our analyses are based on data arising from the integrated mapping of podoconiosis and lymphatic filariasis (LF) conducted in 2013, supplemented by data from an earlier mapping of LF in western Et...

  15. The impact of pesticide suicide on the geographic distribution of suicide in Taiwan: a spatial analysis.

    Science.gov (United States)

    Chang, Shu-Sen; Lu, Tsung-Hsueh; Sterne, Jonathan Ac; Eddleston, Michael; Lin, Jin-Jia; Gunnell, David

    2012-04-02

    Pesticide self-poisoning is the most commonly used suicide method worldwide, but few studies have investigated the national epidemiology of pesticide suicide in countries where it is a major public health problem. This study aims to investigate geographic variations in pesticide suicide and their impact on the spatial distribution of suicide in Taiwan. Smoothed standardized mortality ratios for pesticide suicide (2002-2009) were mapped across Taiwan's 358 districts (median population aged 15 or above = 27 000), and their associations with the size of agricultural workforce were investigated using Bayesian hierarchical models. In 2002-2009 pesticide poisoning was the third most common suicide method in Taiwan, accounting for 13.6% (4913/36 110) of all suicides. Rates were higher in agricultural East and Central Taiwan and lower in major cities. Almost half (47%) of all pesticide suicides occurred in areas where only 13% of Taiwan's population lived. The geographic distribution of overall suicides was more similar to that of pesticide suicides than non-pesticide suicides. Rural-urban differences in suicide were mostly due to pesticide suicide. Areas where a higher proportion of people worked in agriculture showed higher pesticide suicide rates (adjusted rate ratio [ARR] per standard deviation increase in the proportion of agricultural workers = 1.58, 95% Credible Interval [CrI] 1.44-1.74) and overall suicide rates (ARR = 1.06, 95% CrI 1.03-1.10) but lower non-pesticide suicide rates (ARR = 0.91, 95% CrI 0.87-0.95). Easy access to pesticides appears to influence the geographic distribution of suicide in Taiwan, highlighting the potential benefits of targeted prevention strategies such as restricting access to highly toxic pesticides.

  16. Advanced model for expansion of natural gas distribution networks based on geographic information systems

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez-Rosado, I.J.; Fernandez-Jimenez, L.A.; Garcia-Garrido, E.; Zorzano-Santamaria, P.; Zorzano-Alba, E. [La Rioja Univ., La Rioja (Spain). Dept. of Electrical Engineering; Miranda, V.; Montneiro, C. [Porto Univ., Porto (Portugal). Faculty of Engineering]|[Inst. de Engenharia de Sistemas e Computadores do Porto, Porto (Portugal)

    2005-07-01

    An advanced geographic information system (GIS) model of natural gas distribution networks was presented. The raster-based model was developed to evaluate costs associated with the expansion of electrical networks due to increased demand in the La Rioja region of Spain. The model was also used to evaluate costs associated with maintenance and amortization of the already existing distribution network. Expansion costs of the distribution network were modelled in various demand scenarios. The model also considered a variety of technical factors associated with pipeline length and topography. Soil and slope data from previous pipeline projects were used to estimate real costs per unit length of pipeline. It was concluded that results obtained by the model will be used by planners to select zones where expansion is economically feasible. 4 refs., 5 figs.

  17. Climate Change May Alter Breeding Ground Distributions of Eastern Migratory Monarchs (Danaus plexippus) via Range Expansion of Asclepias Host Plants

    Science.gov (United States)

    Lemoine, Nathan P.

    2015-01-01

    Climate change can profoundly alter species’ distributions due to changes in temperature, precipitation, or seasonality. Migratory monarch butterflies (Danaus plexippus) may be particularly susceptible to climate-driven changes in host plant abundance or reduced overwintering habitat. For example, climate change may significantly reduce the availability of overwintering habitat by restricting the amount of area with suitable microclimate conditions. However, potential effects of climate change on monarch northward migrations remain largely unknown, particularly with respect to their milkweed (Asclepias spp.) host plants. Given that monarchs largely depend on the genus Asclepias as larval host plants, the effects of climate change on monarch northward migrations will most likely be mediated by climate change effects on Asclepias. Here, I used MaxEnt species distribution modeling to assess potential changes in Asclepias and monarch distributions under moderate and severe climate change scenarios. First, Asclepias distributions were projected to extend northward throughout much of Canada despite considerable variability in the environmental drivers of each individual species. Second, Asclepias distributions were an important predictor of current monarch distributions, indicating that monarchs may be constrained as much by the availability of Asclepias host plants as environmental variables per se. Accordingly, modeling future distributions of monarchs, and indeed any tightly coupled plant-insect system, should incorporate the effects of climate change on host plant distributions. Finally, MaxEnt predictions of Asclepias and monarch distributions were remarkably consistent among general circulation models. Nearly all models predicted that the current monarch summer breeding range will become slightly less suitable for Asclepias and monarchs in the future. Asclepias, and consequently monarchs, should therefore undergo expanded northern range limits in summer months

  18. Climate change may alter breeding ground distributions of eastern migratory monarchs (Danaus plexippus via range expansion of Asclepias host plants.

    Directory of Open Access Journals (Sweden)

    Nathan P Lemoine

    Full Text Available Climate change can profoundly alter species' distributions due to changes in temperature, precipitation, or seasonality. Migratory monarch butterflies (Danaus plexippus may be particularly susceptible to climate-driven changes in host plant abundance or reduced overwintering habitat. For example, climate change may significantly reduce the availability of overwintering habitat by restricting the amount of area with suitable microclimate conditions. However, potential effects of climate change on monarch northward migrations remain largely unknown, particularly with respect to their milkweed (Asclepias spp. host plants. Given that monarchs largely depend on the genus Asclepias as larval host plants, the effects of climate change on monarch northward migrations will most likely be mediated by climate change effects on Asclepias. Here, I used MaxEnt species distribution modeling to assess potential changes in Asclepias and monarch distributions under moderate and severe climate change scenarios. First, Asclepias distributions were projected to extend northward throughout much of Canada despite considerable variability in the environmental drivers of each individual species. Second, Asclepias distributions were an important predictor of current monarch distributions, indicating that monarchs may be constrained as much by the availability of Asclepias host plants as environmental variables per se. Accordingly, modeling future distributions of monarchs, and indeed any tightly coupled plant-insect system, should incorporate the effects of climate change on host plant distributions. Finally, MaxEnt predictions of Asclepias and monarch distributions were remarkably consistent among general circulation models. Nearly all models predicted that the current monarch summer breeding range will become slightly less suitable for Asclepias and monarchs in the future. Asclepias, and consequently monarchs, should therefore undergo expanded northern range limits in

  19. TNT Maritime Interdiction Operation Experiments: Enabling Radiation Awareness and Geographically Distributed Collaboration for Network-Centric Maritime Interdiction Operations [Preprint

    National Research Council Canada - National Science Library

    Bordetsky, Alex; Dougan, Arden; Chiann, Foo Y; Kilberg, Andres

    2007-01-01

    ...) comprised of long-haul OFDM networks combined with self-forming wireless mesh links to radiation detection sensors, and real-time radiation awareness collaboration with geographically distributed partners...

  20. Effects of phylogeny, leaf traits, and the altitudinal distribution of host plants on herbivore assemblages on congeneric Acer species.

    Science.gov (United States)

    Nakadai, Ryosuke; Murakami, Masashi; Hirao, Toshihide

    2014-08-01

    Historical, niche-based, and stochastic processes have been proposed as the mechanisms that drive community assembly. In plant-herbivore systems, these processes can correspond to phylogeny, leaf traits, and the distribution of host plants, respectively. Although patterns of herbivore assemblages among plant species have been repeatedly examined, the effects of these factors among co-occurring congeneric host plant species have rarely been studied. Our aim was to reveal the process of community assembly for herbivores by investigating the effects of phylogeny, leaf traits, and the altitudinal distribution of closely related host plants of the genus Acer. We sampled leaf functional traits for 30 Acer species in Japan. Using a newly constructed phylogeny, we determined that three of the six measured leaf traits (leaf thickness, C/N ratio, and condensed tannin content) showed a phylogenetic signal. In a field study, we sampled herbivore communities on 14 Acer species within an elevation gradient and examined relationships between herbivore assemblages and host plants. We found that herbivore assemblages were significantly correlated with phylogeny, leaf traits, phylogenetic signals, and the altitudinal distribution of host plants. Our results indicate that the interaction between historical and current ecological processes shapes herbivore community assemblages.

  1. Host density drives the postglacial migration of the tree parasite, Epifagus virginiana.

    Science.gov (United States)

    Tsai, Yi-Hsin Erica; Manos, Paul S

    2010-09-28

    To survive changes in climate, successful species shift their geographic ranges to remain in suitable habitats. For parasites and other highly specialized species, distributional changes not only are dictated by climate but can also be engineered by their hosts. The extent of host control on parasite range expansion is revealed through comparisons of host and parasite migration and demographic histories. However, understanding the codistributional history of entire forest communities is complicated by challenges in synthesizing datasets from multiple interacting species of differing datatypes. Here we integrate genetic and fossil pollen datasets from a host-parasite pair; specifically, the population structure of the parasitic plant (Epifagus virginiana) was compared with both its host (Fagus grandifolia) genetic patterns and abundance data from the paleopollen record of the last 21,000 y. Through tests of phylogeographic structure and spatial linear regression models we find, surprisingly, host range changes had little effect on the parasite's range expansion and instead host density is the main driver of parasite spread. Unlike other symbionts that have been used as proxies to track their host's movements, this parasite's migration routes are incongruent with the host and instead reflect the greater importance of host density in this community's assembly. Furthermore, these results confirm predictions of disease ecological models regarding the role of host density in the spread of pathogens. Due to host density constraints, highly specialized species may have low migration capacities and long lag times before colonization of new areas.

  2. The distribution of weaver ant pheromones on host trees

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2007-01-01

    The visible anal spots deposited by Oecophylla smaragdina ants have been suggested to deter ant prey, affect interspecific competition and facilitate mutualists and parasites in tracking down Oecophylla ants. I measured the density of anal spots on host trees with and without ants and tested for ...... to leaves. Also there was a positive correlation between spot density and the likelihood of being detected by ants. Anal spots may thus function as reliable cues to interacting species and be an important factor in shaping the community around Oecophylla colonies.......The visible anal spots deposited by Oecophylla smaragdina ants have been suggested to deter ant prey, affect interspecific competition and facilitate mutualists and parasites in tracking down Oecophylla ants. I measured the density of anal spots on host trees with and without ants and tested...... for correlations between spot density, ant activity and the likelihood of being detected by an ant. Spots were only found on trees with ants. On ant-trees, spots were distributed throughout the trees but with higher densities in areas with high ant activity and pheromone densities were higher on twigs compared...

  3. Environmental determinants of the spatial distribution of Alaria alata in Hungary.

    Science.gov (United States)

    Széll, Z; Tolnai, Z; Sréter, T

    2013-11-15

    Alaria alata is a potential zoonotic parasite, which is widely distributed in Eurasia. To assess the risk of human infection, it is important to know the spatial distribution pattern of the parasite and factors influencing this pattern. To investigate these relationships, 1612 red fox (Vulpes vulpes) carcasses were randomly collected from the whole Hungarian territory, and the intestines were examined by sedimentation and counting technique. The spatial distribution of the parasite was highly clumped. The topographic positions where the foxes had been shot and the intensity of infections were recorded in geographic information system database. Digitized home ranges of infected and uninfected foxes were analysed on the background of geographic vector data of altitude, land cover types, permanent waters, mean annual temperature, annual precipitation and soil permeability. Multiple regression analysis was performed with environmental parameter values and A. alata scores. Based on the statistical analysis, lack of permanent waters, mean annual temperature, annual precipitation and soil permeability were the major determinants of the spatial distribution of A. alata. It can be explained by the use of biotopes by the intermediate hosts. The lack of permanent waters results in the use of temporary waters by the second intermediate hosts, frogs. The higher temperature, the lower precipitation and the higher soil permeability lead to earlier desiccation of temporary waters, and tadpoles and frogs infected with mesocercariae can be more easily predated by the final hosts (e.g., red foxes). Moreover, temporary waters are more easily contaminated with the faeces of the final hosts containing eggs than permanent waters. Therefore, high infection rate with A. alata can be expected mainly in lowland areas, where the hydrogeography of permanent waters is less complex, the precipitation is lower, the mean temperature and the soil permeability are higher than in highland areas

  4. [Predicting the impact of global warming on the geographical distribution pattern of Quercus variabilis in China].

    Science.gov (United States)

    Li, Yao; Zhang, Xing-wang; Fang, Yan-ming

    2014-12-01

    The geographical distribution of Quercus variabilis in China with its climate characteristics was analyzed based on DIVA-GIS which was also used to estimate the response of future potential distribution to global warming by Bioclim and Domain models. Analysis results showed the geographical distribution of Q. variabilis could be divided into 7 subregions: Henduan Mountains, Yunnan-Guizhou Plateau, North China, East China, Liaodong-Shandong Peninsula, Taiwan Island, and Qinling-Daba Mountains. These subregions are across 7 temperature zones, 2 moisture regions and 17 climatic subregions, including 8 climate types. The modern abundance center of Q. variabilis is Qinling, Daba and Funiu mountains. The condition of mean annual temperature 7.5-19.8 degrees C annual precipitation 471-1511 mm, is suitable for Q. variabilis. Areas under the receiver operating characteristic curve (AUC values), of Domain and Boiclim models were 0.910, 0.779; the former predicted that the potential regions of high suitability for Q. variabilis are Qinling, Daba, Funiu, Tongbai, and Dabie mountains, eastern and western Yunnan-Guizhou Plateau, hills of southern Jiangsu and Anhui, part of the mountains in North China. Global warming might lead to the shrinking in suitable region and retreating from the south for Q. variabilis.

  5. Geographical distribution of complement receptor type 1 variants and their associated disease risk.

    Directory of Open Access Journals (Sweden)

    Thaisa Lucas Sandri

    Full Text Available Pathogens exert selective pressure which may lead to substantial changes in host immune responses. The human complement receptor type 1 (CR1 is an innate immune recognition glycoprotein that regulates the activation of the complement pathway and removes opsonized immune complexes. CR1 genetic variants in exon 29 have been associated with expression levels, C1q or C3b binding and increased susceptibility to several infectious diseases. Five distinct CR1 nucleotide substitutions determine the Knops blood group phenotypes, namely Kna/b, McCa/b, Sl1/Sl2, Sl4/Sl5 and KCAM+/-.CR1 variants were genotyped by direct sequencing in a cohort of 441 healthy individuals from Brazil, Vietnam, India, Republic of Congo and Ghana.The distribution of the CR1 alleles, genotypes and haplotypes differed significantly among geographical settings (p≤0.001. CR1 variants rs17047660A/G (McCa/b and rs17047661A/G (Sl1/Sl2 were exclusively observed to be polymorphic in African populations compared to the groups from Asia and South-America, strongly suggesting that these two SNPs may be subjected to selection. This is further substantiated by a high linkage disequilibrium between the two variants in the Congolese and Ghanaian populations. A total of nine CR1 haplotypes were observed. The CR1*AGAATA haplotype was found more frequently among the Brazilian and Vietnamese study groups; the CR1*AGAATG haplotype was frequent in the Indian and Vietnamese populations, while the CR1*AGAGTG haplotype was frequent among Congolese and Ghanaian individuals.The African populations included in this study might have a selective advantage conferred to immune genes involved in pathogen recognition and signaling, possibly contributing to disease susceptibility or resistance.

  6. The Distribution of Heavy Metal Pollutants in Suez Bay Using Geographic Information System (GIS)

    International Nuclear Information System (INIS)

    Hassan, H.B.; Mohamed, W.M.

    2017-01-01

    Suez city represents the southern entrance of the Suez Canal. As a result of the rapid development of industrialization and anthropogenic activities of Suez city may be entered containments such as heavy metals through Suez bay boundaries. The geographical information system (Arc GIS 9.1) is used to study the spatial distribution of heavy metals concentrations (Cd, Mn, Fe, Ni, Pb, Cu and Zn) of water samples which were collected in four different sampling sites (I, II, III and IV) from Suez bay. In this study, tabular data representation of the spatial distribution was developed using the inverse distance weighted (IDW) interpolation method. The GIS technique was applied to transfer the information into a final map illustrating the spatial distribution of heavy metals within the studied area. GIS models showed the high concentrations of heavy metals in some sites in the Suez city affecting by their activities. An overall distribution map of heavy metals is observed from GIS special analysis. Site (IV) in Suez City demonstrated the highest polluted are a in the overall distribution map

  7. Understanding the geographic distribution of tropical cyclone formation for applications in climate models

    Science.gov (United States)

    Tory, Kevin J.; Ye, H.; Dare, R. A.

    2018-04-01

    Projections of Tropical cyclone (TC) formation under future climate scenarios are dependent on climate model simulations. However, many models produce unrealistic geographical distributions of TC formation, especially in the north and south Atlantic and eastern south Pacific TC basins. In order to improve confidence in projections it is important to understand the reasons behind these model errors. However, considerable effort is required to analyse the many models used in projection studies. To address this problem, a novel diagnostic is developed that provides compelling insight into why TCs form where they do, using a few summary diagrams. The diagnostic is developed after identifying a relationship between seasonal climatologies of atmospheric variables in 34 years of ECMWF reanalysis data, and TC detection distributions in the same data. Geographic boundaries of TC formation are constructed from four threshold quantities. TCs form where Emanuel's Maximum Potential Intensity, V_{{PI}}, exceeds 40 {ms}^{{ - 1}}, 700 hPa relative humidity, RH_{{700}}, exceeds 40%, and the magnitude of the difference in vector winds between 850 and 200 hPa, V_{{sh}}, is less than 20 {ms}^{{ - 1}}. The equatorial boundary is best defined by a composite quantity containing the ratio of absolute vorticity (η ) to the meridional gradient of absolute vorticity (β ^{*}), rather than η alone. {β ^*} is also identified as a potentially important ingredient for TC genesis indices. A comparison of detected Tropical Depression (TD) and Tropical Storm (TS) climatologies revealed TDs more readily intensify further to TS where {V_{PI}} is elevated and {V_{sh}} is relatively weak. The distributions of each threshold quantity identify the factors that favour and suppress TC formation throughout the tropics in the real world. This information can be used to understand why TC formation is poorly represented in some climate models, and shows potential for understanding anomalous TC formation

  8. The impact of pesticide suicide on the geographic distribution of suicide in Taiwan: a spatial analysis

    Directory of Open Access Journals (Sweden)

    Chang Shu-Sen

    2012-04-01

    Full Text Available Abstract Background Pesticide self-poisoning is the most commonly used suicide method worldwide, but few studies have investigated the national epidemiology of pesticide suicide in countries where it is a major public health problem. This study aims to investigate geographic variations in pesticide suicide and their impact on the spatial distribution of suicide in Taiwan. Methods Smoothed standardized mortality ratios for pesticide suicide (2002-2009 were mapped across Taiwan's 358 districts (median population aged 15 or above = 27 000, and their associations with the size of agricultural workforce were investigated using Bayesian hierarchical models. Results In 2002-2009 pesticide poisoning was the third most common suicide method in Taiwan, accounting for 13.6% (4913/36 110 of all suicides. Rates were higher in agricultural East and Central Taiwan and lower in major cities. Almost half (47% of all pesticide suicides occurred in areas where only 13% of Taiwan's population lived. The geographic distribution of overall suicides was more similar to that of pesticide suicides than non-pesticide suicides. Rural-urban differences in suicide were mostly due to pesticide suicide. Areas where a higher proportion of people worked in agriculture showed higher pesticide suicide rates (adjusted rate ratio [ARR] per standard deviation increase in the proportion of agricultural workers = 1.58, 95% Credible Interval [CrI] 1.44-1.74 and overall suicide rates (ARR = 1.06, 95% CrI 1.03-1.10 but lower non-pesticide suicide rates (ARR = 0.91, 95% CrI 0.87-0.95. Conclusion Easy access to pesticides appears to influence the geographic distribution of suicide in Taiwan, highlighting the potential benefits of targeted prevention strategies such as restricting access to highly toxic pesticides.

  9. Quantitative Study of the Geographical Distribution of the Authorship of High-Energy Physics Journals

    CERN Document Server

    Krause, Jan; Mele, S

    2007-01-01

    The recent debate on Open Access publishing in High-Energy Physics has exposed the problem of assessing the scienti c production of every country where scholars are active in this discipline. This assessment is complicated by the highly-collaborative cross-border tradition of High-Energy Physics research. We present the results of a quantitative study of the geographical distribution of authors of High-Energy Physics articles, which takes into account cross-border co-authorship by attributing articles to countries on a pro-rata basis. Aggregated data on the share of scienti c results published by each country are presented together with a breakdown for the most popular journals in the eld, and a separation for articles by small groups or large collaborations. Collaborative patterns across large geographic areas are also investigated. Finally, the High-Energy Physics production of each country is compared with some economic indicators.

  10. Colonization history, host distribution, anthropogenic influence and landscape features shape populations of white pine blister rust, an invasive alien tree pathogen.

    Directory of Open Access Journals (Sweden)

    Simren Brar

    Full Text Available White pine blister rust is caused by the fungal pathogen Cronartium ribicola J.C. Fisch (Basidiomycota, Pucciniales. This invasive alien pathogen was introduced into North America at the beginning of the 20th century on pine seedlings imported from Europe and has caused serious economic and ecological impacts. In this study, we applied a population and landscape genetics approach to understand the patterns of introduction and colonization as well as population structure and migration of C. ribicola. We characterized 1,292 samples of C. ribicola from 66 geographic locations in North America using single nucleotide polymorphisms (SNPs and evaluated the effect of landscape features, host distribution, and colonization history on the structure of these pathogen populations. We identified eastern and western genetic populations in North America that are strongly differentiated. Genetic diversity is two to five times higher in eastern populations than in western ones, which can be explained by the repeated accidental introductions of the pathogen into northeastern North America compared with a single documented introduction into western North America. These distinct genetic populations are maintained by a barrier to gene flow that corresponds to a region where host connectivity is interrupted. Furthermore, additional cryptic spatial differentiation was identified in western populations. This differentiation corresponds to landscape features, such as mountain ranges, and also to host connectivity. We also detected genetic differentiation between the pathogen populations in natural stands and plantations, an indication that anthropogenic movement of this pathogen still takes place. These results highlight the importance of monitoring this invasive alien tree pathogen to prevent admixture of eastern and western populations where different pathogen races occur.

  11. Random-growth urban model with geographical fitness

    Science.gov (United States)

    Kii, Masanobu; Akimoto, Keigo; Doi, Kenji

    2012-12-01

    This paper formulates a random-growth urban model with a notion of geographical fitness. Using techniques of complex-network theory, we study our system as a type of preferential-attachment model with fitness, and we analyze its macro behavior to clarify the properties of the city-size distributions it predicts. First, restricting the geographical fitness to take positive values and using a continuum approach, we show that the city-size distributions predicted by our model asymptotically approach Pareto distributions with coefficients greater than unity. Then, allowing the geographical fitness to take negative values, we perform local coefficient analysis to show that the predicted city-size distributions can deviate from Pareto distributions, as is often observed in actual city-size distributions. As a result, the model we propose can generate a generic class of city-size distributions, including but not limited to Pareto distributions. For applications to city-population projections, our simple model requires randomness only when new cities are created, not during their subsequent growth. This property leads to smooth trajectories of city population growth, in contrast to other models using Gibrat’s law. In addition, a discrete form of our dynamical equations can be used to estimate past city populations based on present-day data; this fact allows quantitative assessment of the performance of our model. Further study is needed to determine appropriate formulas for the geographical fitness.

  12. Temperature effects on gametophyte life-history traits and geographic distribution of two cryptic kelp species.

    Directory of Open Access Journals (Sweden)

    L Valeria Oppliger

    Full Text Available A major determinant of the geographic distribution of a species is expected to be its physiological response to changing abiotic variables over its range. The range of a species often corresponds to the geographic extent of temperature regimes the organism can physiologically tolerate. Many species have very distinct life history stages that may exhibit different responses to environmental factors. In this study we emphasized the critical role of the haploid microscopic stage (gametophyte of the life cycle to explain the difference of edge distribution of two related kelp species. Lessonia nigrescens was recently identified as two cryptic species occurring in parapatry along the Chilean coast: one located north and the other south of a biogeographic boundary at latitude 29-30°S. Six life history traits from microscopic stages were identified and estimated under five treatments of temperature in eight locations distributed along the Chilean coast in order to (1 estimate the role of temperature in the present distribution of the two cryptic L. nigrescens species, (2 compare marginal populations to central populations of the two cryptic species. In addition, we created a periodic matrix model to estimate the population growth rate (λ at the five temperature treatments. Differential tolerance to temperature was demonstrated between the two species, with the gametophytes of the Northern species being more tolerant to higher temperatures than gametophytes from the south. Second, the two species exhibited different life history strategies with a shorter haploid phase in the Northern species contrasted with considerable vegetative growth in the Southern species haploid stage. These results provide strong ecological evidence for the differentiation process of the two cryptic species and show local adaptation of the life cycle at the range limits of the distribution. Ecological and evolutionary implications of these findings are discussed.

  13. Diversity, natural history, and geographic distribution of snakes in the Caatinga, Northeastern Brazil.

    Science.gov (United States)

    Guedes, Thaís B; Nogueira, Cristiano; Marques, Otavio A V

    2014-09-19

    The present study is a synthesis on snake diversity and distribution in the Caatinga region of northeastern Brazil, providing an updated species list and data on natural history and geographic distribution. Our study is based on the careful revision of 7,102 voucher specimens, housed in 17 herpetological collections, complemented by data on taxonomic literature. We recorded a total of 112 snake species in the Caatinga, belonging to nine families: Anomalepididae, Leptotyphlopidae, Typhlopidae, Aniliidae, Boidae, Viperidae, Elapidae, Colubridae, and Dipsadidae. Our list includes at least 13 never recorded species for this region, as well as distribution records for all species known from the Caatinga (including expansion and new records of distribution). The snake assemblage of the Caatinga is complex, sharing species with other continental open areas (38.4%), forested areas (27.7%), and both open and forested areas (32.1%). The richest areas were isolated plateaus, followed by contact areas, semi-arid caatinga, and sandy dunes of the São Franscisco River. We identified 22 Caatinga endemic species with the sandy dunes of São Franscico River showing the highest endemism level (12 species, with six endemic species restricted to the area) followed by semi-arid caatinga, and isolated plateaus (eight endemic species each, and six and three endemic species with restricted distribution to each area, respectively). Most species show relatively restricted ranges in parts of the Caatinga. The snake assemblage in Caatinga includes mainly terrestrial species (38.4%), followed by fossorial/cryptozoic (26.8%), arboreal/semi-arboreal (26.8%), and aquatic/semi-aquatic (7.1%) species. Vertebrates are the most important dietary item (80.4%), with 56.6% of species being generalist consumers of this kind of prey; 24.4% are frog-eaters, 7.8% prey on caecilians/amphisbaenians, 6.7% lizard-eaters, 3.3% mammal-eaters, and 1.1% are fish-eaters. Only 18.7% of the snakes eat invertebrate

  14. Tracking the evolutionary history of Cortinarius species in section Calochroi, with transoceanic disjunct distributions.

    Science.gov (United States)

    Garnica, Sigisfredo; Spahn, Philipp; Oertel, Bernhard; Ammirati, Joseph; Oberwinkler, Franz

    2011-07-19

    Cortinarius species in section Calochroi display local, clinal and circumboreal patterns of distribution across the Northern Hemisphere where these ectomycorrhizal fungi occur with host trees throughout their geographical range within a continent, or have disjunct intercontinental distributions, the origins of which are not understood. We inferred evolutionary histories of four species, 1) C. arcuatorum, 2) C. aureofulvus, 3) C. elegantior and 4) C. napus, from populations distributed throughout the Old World, and portions of the New World (Central- and North America) based on genetic variation of 154 haplotype internal transcribed spacer (ITS) sequences from 83 population samples. By describing the population structure of these species across their geographical distribution, we attempt to identify their historical migration and patterns of diversification. Models of population structure from nested clade, demographic and coalescent-based analyses revealed genetically differentiated and geographically structured haplotypes in C. arcuatorum and C. elegantior, while C. aureofulvus showed considerably less population structure and C. napus lacked sufficient genetic differentiation to resolve any population structure. Disjunct populations within C. arcuatorum, C. aureofulvus and C. elegantior show little or no morphological differentiation, whereas in C. napus there is a high level of homoplasy and phenotypic plasticity for veil and lamellae colour. The ITS sequences of the type specimens of C. albobrunnoides and C. albobrunnoides var. violaceovelatus were identical to one another and are treated as one species with a wider range of geographic distribution under C. napus. Our results indicate that each of the Calochroi species has undergone a relatively independent evolutionary history, hypothesised as follows: 1) a widely distributed ancestral population of C. arcuatorum diverged into distinctive sympatric populations in the New World; 2) two divergent lineages in C

  15. Phylogenetic Diversity, Distribution, and Cophylogeny of Giant Bacteria (Epulopiscium) with their Surgeonfish Hosts in the Red Sea

    KAUST Repository

    Miyake, Sou

    2016-03-14

    Epulopiscium is a group of giant bacteria found in high abundance in intestinal tracts of herbivorous surgeonfish. Despite their peculiarly large cell size (can be up to 600 μm), extreme polyploidy (some with over 100,000 genome copies per cell) and viviparity (whereby mother cells produce live offspring), details about their diversity, distribution or their role in the host gut are lacking. Previous studies have highlighted the existence of morphologically distinct Epulopiscium cell types (defined as morphotypes A to J) in some surgeonfish genera, but the corresponding genetic diversity and distribution among other surgeonfishes remain mostly unknown. Therefore, we investigated the phylogenetic diversity of Epulopiscium, distribution and co-occurrence in multiple hosts. Here, we identified eleven new phylogenetic clades, six of which were also morphologically characterized. Three of these novel clades were phylogenetically and morphologically similar to cigar-shaped type A1 cells, found in a wide range of surgeonfishes including Acanthurus nigrofuscus, while three were similar to smaller, rod-shaped type E that has not been phylogenetically classified thus far. Our results also confirmed that biogeography appears to have relatively little influence on Epulopiscium diversity, as clades found in the Great Barrier Reef and Hawaii were also recovered from the Red Sea. Although multiple symbiont clades inhabited a given species of host surgeonfish and multiple host species possessed a given symbiont clade, statistical analysis of host and symbiont phylogenies indicated significant cophylogeny, which in turn suggests co-evolutionary relationships. A cluster analysis of Epulopiscium sequences from previously published amplicon sequencing dataset revealed a similar pattern, where specific clades were consistently found in high abundance amongst closely related surgeonfishes. Differences in abundance may indicate specialization of clades to certain gut environments

  16. Phylogenetic Diversity, Distribution, and Cophylogeny of Giant Bacteria (Epulopiscium) with their Surgeonfish Hosts in the Red Sea

    Science.gov (United States)

    Miyake, Sou; Ngugi, David K.; Stingl, Ulrich

    2016-01-01

    Epulopiscium is a group of giant bacteria found in high abundance in intestinal tracts of herbivorous surgeonfish. Despite their peculiarly large cell size (can be up to 600 μm), extreme polyploidy (some with over 100,000 genome copies per cell) and viviparity (whereby mother cells produce live offspring), details about their diversity, distribution or their role in the host gut are lacking. Previous studies have highlighted the existence of morphologically distinct Epulopiscium cell types (defined as morphotypes A to J) in some surgeonfish genera, but the corresponding genetic diversity and distribution among other surgeonfishes remain mostly unknown. Therefore, we investigated the phylogenetic diversity of Epulopiscium, distribution and co-occurrence in multiple hosts. Here, we identified eleven new phylogenetic clades, six of which were also morphologically characterized. Three of these novel clades were phylogenetically and morphologically similar to cigar-shaped type A1 cells, found in a wide range of surgeonfishes including Acanthurus nigrofuscus, while three were similar to smaller, rod-shaped type E that has not been phylogenetically classified thus far. Our results also confirmed that biogeography appears to have relatively little influence on Epulopiscium diversity, as clades found in the Great Barrier Reef and Hawaii were also recovered from the Red Sea. Although multiple symbiont clades inhabited a given species of host surgeonfish and multiple host species possessed a given symbiont clade, statistical analysis of host and symbiont phylogenies indicated significant cophylogeny, which in turn suggests co-evolutionary relationships. A cluster analysis of Epulopiscium sequences from previously published amplicon sequencing dataset revealed a similar pattern, where specific clades were consistently found in high abundance amongst closely related surgeonfishes. Differences in abundance may indicate specialization of clades to certain gut environments

  17. Phylogenetic Diversity, Distribution, and Cophylogeny of Giant Bacteria (Epulopiscium) with their Surgeonfish Hosts in the Red Sea

    KAUST Repository

    Miyake, Sou; Ngugi, David; Stingl, Ulrich

    2016-01-01

    Epulopiscium is a group of giant bacteria found in high abundance in intestinal tracts of herbivorous surgeonfish. Despite their peculiarly large cell size (can be up to 600 μm), extreme polyploidy (some with over 100,000 genome copies per cell) and viviparity (whereby mother cells produce live offspring), details about their diversity, distribution or their role in the host gut are lacking. Previous studies have highlighted the existence of morphologically distinct Epulopiscium cell types (defined as morphotypes A to J) in some surgeonfish genera, but the corresponding genetic diversity and distribution among other surgeonfishes remain mostly unknown. Therefore, we investigated the phylogenetic diversity of Epulopiscium, distribution and co-occurrence in multiple hosts. Here, we identified eleven new phylogenetic clades, six of which were also morphologically characterized. Three of these novel clades were phylogenetically and morphologically similar to cigar-shaped type A1 cells, found in a wide range of surgeonfishes including Acanthurus nigrofuscus, while three were similar to smaller, rod-shaped type E that has not been phylogenetically classified thus far. Our results also confirmed that biogeography appears to have relatively little influence on Epulopiscium diversity, as clades found in the Great Barrier Reef and Hawaii were also recovered from the Red Sea. Although multiple symbiont clades inhabited a given species of host surgeonfish and multiple host species possessed a given symbiont clade, statistical analysis of host and symbiont phylogenies indicated significant cophylogeny, which in turn suggests co-evolutionary relationships. A cluster analysis of Epulopiscium sequences from previously published amplicon sequencing dataset revealed a similar pattern, where specific clades were consistently found in high abundance amongst closely related surgeonfishes. Differences in abundance may indicate specialization of clades to certain gut environments

  18. Ethnic and geographic variations in HPV prevalence and genotype distribution in north-western Yunnan, China.

    Science.gov (United States)

    Baloch, Zulqarnain; Yuan, Tao; Wang, Binghui; Tai, Wenlin; Feng, Yue; Liu, Yanqing; Li, Xiao; Feng, Yue; Liu, Li; Zhang, A-mei; Wu, Xiaomei; Xia, Xueshan

    2016-03-01

    The prevalence and genotype distribution of human papillomavirus (HPV) vary throughout the world. To assess the prevalence and genotype distribution of HPV among three ethnic groups in two geographic locations in north-western Yunnan, we recruited 522 women in Shangri-le (n = 255) and Lijiang (n = 267). PCR amplification of HPV DNA was performed on cervical cells from these women using two consensus primer systems (MY09/11 and GP5/6). Amplified-HPV DNA was genotyped using the HPV GenoArray test. Geographically, the HPV prevalence was significantly higher (P = 0.002) among Shangri-le women than among Lijiang women. Infections with high-risk (HR)-HPV and with multiple HPV genotypes were also significantly more common (P = 0.001) among women in Shangri-le than women in Lijiang. Additionally, the prevalence of overall, HR-HPV, and single genotype HPV infections was significantly higher (P = 0.001) among Tibetan women than among Naxi and Han women. HPV-16 and HPV-33 were significantly more frequent in Shangri-le women compared with Lijiang (P = 0.006) women. In addition, HPV-16 (9.81%) and HPV-33 (5.88%) were significantly more prevalent in Tibetan women than in Naxi and Han women. Here, for the first time, we highlight the significant variation in the prevalence and genotype distribution of HPV in various populations in the north-western region of Yunnan Province. © 2015 Wiley Periodicals, Inc.

  19. Geographic information system-coupling sediment delivery distributed modeling based on observed data.

    Science.gov (United States)

    Lee, S E; Kang, S H

    2014-01-01

    Spatially distributed sediment delivery (SEDD) models are of great interest in estimating the expected effect of changes on soil erosion and sediment yield. However, they can only be applied if the model can be calibrated using observed data. This paper presents a geographic information system (GIS)-based method to calculate the sediment discharge from basins to coastal areas. For this, an SEDD model, with a sediment rating curve method based on observed data, is proposed and validated. The model proposed here has been developed using the combined application of the revised universal soil loss equation (RUSLE) and a spatially distributed sediment delivery ratio, within Model Builder of ArcGIS's software. The model focuses on spatial variability and is useful for estimating the spatial patterns of soil loss and sediment discharge. The model consists of two modules, a soil erosion prediction component and a sediment delivery model. The integrated approach allows for relatively practical and cost-effective estimation of spatially distributed soil erosion and sediment delivery, for gauged or ungauged basins. This paper provides the first attempt at estimating sediment delivery ratio based on observed data in the monsoon region of Korea.

  20. Changes in the geographical distribution of plant species and climatic variables on the West Cornwall peninsula (South West UK).

    Science.gov (United States)

    Kosanic, Aleksandra; Anderson, Karen; Harrison, Stephan; Turkington, Thea; Bennie, Jonathan

    2018-01-01

    Recent climate change has had a major impact on biodiversity and has altered the geographical distribution of vascular plant species. This trend is visible globally; however, more local and regional scale research is needed to improve understanding of the patterns of change and to develop appropriate conservation strategies that can minimise cultural, health, and economic losses at finer scales. Here we describe a method to manually geo-reference botanical records from a historical herbarium to track changes in the geographical distributions of plant species in West Cornwall (South West England) using both historical (pre-1900) and contemporary (post-1900) distribution records. We also assess the use of Ellenberg and climate indicator values as markers of responses to climate and environmental change. Using these techniques we detect a loss in 19 plant species, with 6 species losing more than 50% of their previous range. Statistical analysis showed that Ellenberg (light, moisture, nitrogen) and climate indicator values (mean January temperature, mean July temperature and mean precipitation) could be used as environmental change indicators. Significantly higher percentages of area lost were detected in species with lower January temperatures, July temperatures, light, and nitrogen values, as well as higher annual precipitation and moisture values. This study highlights the importance of historical records in examining the changes in plant species' geographical distributions. We present a method for manual geo-referencing of such records, and demonstrate how using Ellenberg and climate indicator values as environmental and climate change indicators can contribute towards directing appropriate conservation strategies.

  1. Changes in the geographical distribution of plant species and climatic variables on the West Cornwall peninsula (South West UK)

    Science.gov (United States)

    Kosanic, Aleksandra; Anderson, Karen; Harrison, Stephan; Turkington, Thea; Bennie, Jonathan

    2018-01-01

    Recent climate change has had a major impact on biodiversity and has altered the geographical distribution of vascular plant species. This trend is visible globally; however, more local and regional scale research is needed to improve understanding of the patterns of change and to develop appropriate conservation strategies that can minimise cultural, health, and economic losses at finer scales. Here we describe a method to manually geo-reference botanical records from a historical herbarium to track changes in the geographical distributions of plant species in West Cornwall (South West England) using both historical (pre-1900) and contemporary (post-1900) distribution records. We also assess the use of Ellenberg and climate indicator values as markers of responses to climate and environmental change. Using these techniques we detect a loss in 19 plant species, with 6 species losing more than 50% of their previous range. Statistical analysis showed that Ellenberg (light, moisture, nitrogen) and climate indicator values (mean January temperature, mean July temperature and mean precipitation) could be used as environmental change indicators. Significantly higher percentages of area lost were detected in species with lower January temperatures, July temperatures, light, and nitrogen values, as well as higher annual precipitation and moisture values. This study highlights the importance of historical records in examining the changes in plant species’ geographical distributions. We present a method for manual geo-referencing of such records, and demonstrate how using Ellenberg and climate indicator values as environmental and climate change indicators can contribute towards directing appropriate conservation strategies. PMID:29401494

  2. DISTRIBUTION OF ANOPLOSEFALYATS (FAUNA, TAXONOMY AND BIOLOGY IN DOMESTIC RUMINANTS ANIMALS OF AZERBAIJAN AND THEIR ECOLOGICAL-GEOGRAPHIC ANALYSIS

    Directory of Open Access Journals (Sweden)

    G. D. Ismailov

    2012-01-01

    Full Text Available Anoplotsefalyats (Moniezia expansa, M. benedeni, M.autumnalia, Avitellina centripunctata, Thyzaniezia giardi are common in farm ruminants of Azerbaijan. There are no strict zoning in their distribution and no specificity for the hosts. It was established that in Azerbaijan there are 27 species of oribatid mites that are involved in the life cycle of monieziozis out of which 20 species recorded to be new to our fauna, as their intermediate hosts. Infection of the final (sheep, goats, cattle, buffalo and intermediate hosts (oribatid mites happens all the year round. Maximum infection occurs in early spring and late autumn.

  3. Relative importance of meteorological and geographical factors in the distribution of Fasciola hepatica infestation in farmed sheep in Qinghai province, China

    Directory of Open Access Journals (Sweden)

    Qin Hongyu

    2016-01-01

    Full Text Available Fasciola hepatica is an important trematode parasite of economic importance that infests sheep and cattle worldwide. We conducted a detailed investigation into the spatial distribution of F. hepatica infestation in farmed sheep in Qinghai (Wutumeiren province, Mainland China. Mathematical modelling was used to assess the inter-relationships between meteorological and geographical factors and the risk of F. hepatica infestation across the province. A capture enzyme-linked immunosorbent assay (ELISA test (MM3-SERO was used to detect F. hepatica infestation. A niche model based on the maximum entropy method (MaxEnt was used to estimate the influence of meteorological and geographical factors on the observed spatial distribution of F. hepatica infestation. Results of jackknife analysis indicated that temperature, precipitation, solar radiation, digital elevation and slope were associated with the occurrence of F. hepatica infestation, and that infestation rates were significantly higher among animals from districts with a high percentage of grassland habitat. The findings indicate that meteorological and geographical factors may be important variables affecting the distribution of F. hepatica infestation and should be taken into account in the development of future surveillance and control programmes for fascioliasis.

  4. Broad-scale Population Genetics of the Host Sea Anemone, Heteractis magnifica

    KAUST Repository

    Emms, Madeleine

    2015-12-01

    Broad-scale population genetics can reveal population structure across an organism’s entire range, which can enable us to determine the most efficient population-wide management strategy depending on levels of connectivity. Genetic variation and differences in genetic diversity on small-scales have been reported in anemones, but nothing is known about their broad-scale population structure, including that of “host” anemone species, which are increasingly being targeted in the aquarium trade. In this study, microsatellite markers were used as a tool to determine the population structure of a sessile, host anemone species, Heteractis magnifica, across the Indo-Pacific region. In addition, two rDNA markers were used to identify Symbiodinium from the samples, and phylogenetic analyses were used to measure diversity and geographic distribution of Symbiodinium across the region. Significant population structure was identified in H. magnifica across the Indo-Pacific, with at least three genetic breaks, possibly the result of factors such as geographic distance, geographic isolation and environmental variation. Symbiodinium associations were also affected by environmental variation and supported the geographic isolation of some regions. These results suggests that management of H. magnifica must be implemented on a local scale, due to the lack of connectivity between clusters. This study also provides further evidence for the combined effects of geographic distance and environmental distance in explaining genetic variance.

  5. ON THE DISTRIBUTION OF STELLAR MASSES IN GAMMA-RAY BURST HOST GALAXIES

    International Nuclear Information System (INIS)

    Castro Ceron, J. M.; Michalowski, M. J.; Hjorth, J.; Malesani, D.; Watson, D.; Fynbo, J. P. U.; Gorosabel, J.; Morales Calderon, M.

    2010-01-01

    We analyze Spitzer images of 30 long-duration gamma-ray burst (GRB) host galaxies. We estimate their total stellar masses (M * ) based on the rest-frame K-band luminosities (L K rest ) and constrain their star formation rates (SFRs; not corrected for dust extinction) based on the rest-frame UV continua. Further, we compute a mean M * /L K rest = 0.45 M sun /L sun . We find that the hosts are low M * , star-forming systems. The median M * in our sample ((M * ) = 10 9.7 M sun ) is lower than that of 'field' galaxies (e.g., Gemini Deep Deep Survey). The range spanned by M * is 10 7 M sun * 11 M sun , while the range spanned by the dust-uncorrected UV SFR is 10 -2 M sun yr -1 sun yr -1 . There is no evidence for intrinsic evolution in the distribution of M * with redshift. We show that extinction by dust must be present in at least 25% of the GRB hosts in our sample and suggest that this is a way to reconcile our finding of a relatively lower UV-based, specific SFR (φ ≡ SFR/M * ) with previous claims that GRBs have some of the highest φ values. We also examine the effect that the inability to resolve the star-forming regions in the hosts has on φ.

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

    Science.gov (United States)

    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.

  7. Echinostoma revolutum: freshwater snails as the second intermediate hosts in Chiang Mai, Thailand.

    Science.gov (United States)

    Chantima, Kittichai; Chai, Jong-Yil; Wongsawad, Chalobol

    2013-04-01

    The occurrence of 37-collar spined echinostome metacercariae in freshwater snails was investigated in 6 districts of Chiang Mai Province, Thailand, from October 2011 to April 2012. A total of 2,914 snails that belong to 12 species were examined, and 7 snail species (Clea helena, Eyriesia eyriesi, Bithynia funiculata, Bithynia siamensis siamensis, Filopaludina doliaris, Filopaludina sumatrensis polygramma, and Filopaludina martensi martensi) were found infected with echinostome metacercariae. The prevalence of metacercariae was the highest in Filopaludina spp. (38.5-58.7%) followed by B. funiculata (44.0%), E. eyriesi (12.5%), B. siamensis siamensis (8.2%), and C. helena (5.1%). Metacercariae were experimentally fed to hamsters and domestic chicks, and adult flukes were recovered from both hosts at days 15 and 20 post-infection. The adult flukes were identified based on morphological features, morphometrics, host-parasite relationships, and geographical distribution. They were compatible to Echinostoma revolutum or Echinostoma jurini, with only minor differences. As the adults were recovered from both hamsters and chicks, our specimens were more compatible to E. revolutum rather than E. jurini (reported only from mammals). This is the first report for metacercariae of E. revolutum in the snail host, C. helena, and also confirmed that Filopaludina spp., E. eryresi, and Bithynia spp. act as the second intermediate hosts of E. revolutum under natural conditions, which are indigenously distributed in Chiang Mai province.

  8. Fine scale distribution constrains cadmium accumulation rates in two geographical groups of Franciscana dolphin from Argentina

    International Nuclear Information System (INIS)

    Polizzi, P.S.; Chiodi Boudet, L.N.; Romero, M.B.; Denuncio, P.E.; Rodríguez, D.H.

    2013-01-01

    Highlights: • Fine scale distribution of two Argentine stocks constrains the Cd accumulation rates. • Cadmium levels and accumulation patterns were different between geographic groups. • Marine diet has a major influence than the impact degree of origin environment. • Engraulis anchoita is the main Cd vector species in Argentine shelf for Franciscana. • Information is valuable for the conservation of Franciscana, a vulnerable species. -- Abstract: Franciscana dolphin is an endemic cetacean in the southwestern Atlantic Ocean and is classified as Vulnerable A3d by the International Union for Conservation of Nature. Cadmium accumulation was assessed in two geographic groups from Argentina; one inhabits the La Plata River estuary, a high anthropogenic impacted environment, and the other is distributed in marine coastal, with negligible pollution. Despite the environment, marine dolphins showed an increase of renal Cd concentrations since trophic independence; while in estuarine dolphins was from 6 years. This is associated with dietary Argentine anchovy which was absent in the diet of estuarine dolphins, being a trophic vector of cadmium in shelf waters of Argentina. Cluster analysis also showed high levels of cd in association with the presence of anchovy in the stomach. The difference in the fine scale distribution of species influences dietary exposure to Cd and, along with other data, indicates two stocks in Argentina

  9. [Potential distribution and geographic characteristics of wild populations of Vanilla planifolia (Orchidaceae) Oaxaca, Mexico].

    Science.gov (United States)

    Hernandez-Ruiz, Jesús; Herrera-Cabrera, B Edgar; Delgado-Alvarado, Adriana; Salazar-Rojas, Víctor M; Bustamante-Gonzalez, Ángel; Campos-Contreras, Jorge E; Ramírez-Juarez, Javier

    2016-03-01

    Wild specimens of Vanilla planifolia represent a vital part of this resource primary gene pool, and some plants have only been reported in Oaxaca, Mexico. For this reason, we studied its geographical distribution within the state, to locate and describe the ecological characteristics of the areas where they have been found, in order to identify potential areas of establishment. The method comprised four stages: 1) the creation of a database with herbarium records, 2) the construction of the potential distribution based on historical herbarium records for the species, using the model of maximum entropy (MaxEnt) and 22 bioclimatic variables as predictors; 3) an in situ systematic search of individuals, based on herbarium records and areas of potential distribution in 24 municipalities, to determine the habitat current situation and distribution; 4) the description of the environmental factors of potential ecological niches generated by MaxEnt. A review of herbarium collections revealed a total of 18 records of V. planifolia between 1939 and 1998. The systematic search located 28 plants distributed in 12 sites in 95 364 Km(2). The most important variables that determined the model of vanilla potential distribution were: precipitation in the rainy season (61.9 %), soil moisture regime (23.4 %) and precipitation during the four months of highest rainfall (8.1 %). The species potential habitat was found to be distributed in four zones: wet tropics of the Gulf of Mexico, humid temperate, humid tropical, and humid temperate in the Pacific. Precipitation oscillated within the annual ranges of 2 500 to 4 000 mm, with summer rains, and winter precipitation as 5 to 10 % of the total. The moisture regime and predominating climate were udic type I (330 to 365 days of moisture) and hot humid (Am/A(C) m). The plants were located at altitudes of 200 to 1 190 masl, on rough hillsides that generally make up the foothills of mountain systems, with altitudes of 1 300 to 2 500 masl. In

  10. Modelling the geographical distribution of soil-transmitted helminth infections in Bolivia.

    Science.gov (United States)

    Chammartin, Frédérique; Scholte, Ronaldo G C; Malone, John B; Bavia, Mara E; Nieto, Prixia; Utzinger, Jürg; Vounatsou, Penelope

    2013-05-25

    The prevalence of infection with the three common soil-transmitted helminths (i.e. Ascaris lumbricoides, Trichuris trichiura, and hookworm) in Bolivia is among the highest in Latin America. However, the spatial distribution and burden of soil-transmitted helminthiasis are poorly documented. We analysed historical survey data using Bayesian geostatistical models to identify determinants of the distribution of soil-transmitted helminth infections, predict the geographical distribution of infection risk, and assess treatment needs and costs in the frame of preventive chemotherapy. Rigorous geostatistical variable selection identified the most important predictors of A. lumbricoides, T. trichiura, and hookworm transmission. Results show that precipitation during the wettest quarter above 400 mm favours the distribution of A. lumbricoides. Altitude has a negative effect on T. trichiura. Hookworm is sensitive to temperature during the coldest month. We estimate that 38.0%, 19.3%, and 11.4% of the Bolivian population is infected with A. lumbricoides, T. trichiura, and hookworm, respectively. Assuming independence of the three infections, 48.4% of the population is infected with any soil-transmitted helminth. Empirical-based estimates, according to treatment recommendations by the World Health Organization, suggest a total of 2.9 million annualised treatments for the control of soil-transmitted helminthiasis in Bolivia. We provide estimates of soil-transmitted helminth infections in Bolivia based on high-resolution spatial prediction and an innovative variable selection approach. However, the scarcity of the data suggests that a national survey is required for more accurate mapping that will govern spatial targeting of soil-transmitted helminthiasis control.

  11. EFFECTS OF VARIOUS SOIL ENVIRONMENTAL STRESSES ON THE OCCURRENCE, DISTRIBUTION AND EFFECTIVENESS OF VA MYCORRHIZAE

    Directory of Open Access Journals (Sweden)

    A.G. KHAN

    1995-01-01

    Full Text Available The vesicular - arbuscular (VA mycorrhizal fungi are geographically ubiquitous soil inhabitants and form universal symbiotic relationship with plants from every phylum. These fungi link host plants with host soils and their biota in the mycorrhizosphere and play an important role in plant health, productivity and soil structure. Although VA mycorrhizal fungi do not show any host specificity, there is increasing evidence that various climatic and edaphic environmental factors such as land use and management practices, physical, chemical and biological properties of host soils and host plant characteristics influence their occurrence, taxonomic distribution and effectiveness. The interaction of these factors with vesicular-arbuscular mycorrhizae (VAM is poorly understood except in a few cases. It is now very clear that VA mycorrhizal associations are ecologically significant factors that require more attention than previously accorded. This paper discusses the occurrence, distribution and significance of VAM in environmentally stressed soil conditions that limit plant growth such as drought, waterlogging and salinity.

  12. Using Geographic Information System-based Ecologic Niche Models to Forecast the Risk of Hantavirus Infection in Shandong Province, China

    Science.gov (United States)

    Wei, Lan; Qian, Quan; Wang, Zhi-Qiang; Glass, Gregory E.; Song, Shao-Xia; Zhang, Wen-Yi; Li, Xiu-Jun; Yang, Hong; Wang, Xian-Jun; Fang, Li-Qun; Cao, Wu-Chun

    2011-01-01

    Hemorrhagic fever with renal syndrome (HFRS) is an important public health problem in Shandong Province, China. In this study, we combined ecologic niche modeling with geographic information systems (GIS) and remote sensing techniques to identify the risk factors and affected areas of hantavirus infections in rodent hosts. Land cover and elevation were found to be closely associated with the presence of hantavirus-infected rodent hosts. The averaged area under the receiver operating characteristic curve was 0.864, implying good performance. The predicted risk maps based on the model were validated both by the hantavirus-infected rodents' distribution and HFRS human case localities with a good fit. These findings have the applications for targeting control and prevention efforts. PMID:21363991

  13. Age and Geographical Distribution in Families with BRCA1/BRCA2 Mutations in the Slovak Republic

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    Ciernikova Sona

    2006-12-01

    Full Text Available Abstract Molecular diagnostics of hereditary breast and/or ovarian cancer is mainly based on detection of BRCA1 and BRCA2 germline mutations in suspected families. The aim of the study was to determine the frequency, age and geographical distribution in 130 Slovak hereditary breast and ovarian cancer (HBOC families diagnosed within the years 2000-2004. Mutation screening was performed by single-strand conformation polymorphism (SSCP, heteroduplex analysis (HDA and sequencing of PCR products showing an abnormal migration pattern. Twenty of 130 (15.6% HBOC suspected families were found to carry mutations in BRCA1 or BRCA2 genes. The glossary data from the National Cancer Registry of Slovakia (NCRS were compared with the results from HBOC suspected kindreds. Age distribution of breast cancer onset in our study group showed the highest proportion of onset in HBC families within the 5th decade of life, while NCRS reports at least a ten year later onset. These findings confirmed that cases of breast cancer under 50 years of age can be used as one of the principal criteria to assign a family as a hereditary breast and/or ovarian cancer kindred. In contrast with unselected ovarian cancer cases, about 75% of all HOC index cases were diagnosed between 40 and 49 years of age. To study the geographical distribution of hereditary breast and/or ovarian cancer, Slovakia was divided into three parts. The distribution of HBOC suspected families approximately follows this division, with an increasing number in the western area of the country.

  14. Multiple sclerosis: a geographical hypothesis.

    Science.gov (United States)

    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.

  15. Brucella Genetic Variability in Wildlife Marine Mammals Populations Relates to Host Preference and Ocean Distribution.

    Science.gov (United States)

    Suárez-Esquivel, Marcela; Baker, Kate S; Ruiz-Villalobos, Nazareth; Hernández-Mora, Gabriela; Barquero-Calvo, Elías; González-Barrientos, Rocío; Castillo-Zeledón, Amanda; Jiménez-Rojas, César; Chacón-Díaz, Carlos; Cloeckaert, Axel; Chaves-Olarte, Esteban; Thomson, Nicholas R; Moreno, Edgardo; Guzmán-Verri, Caterina

    2017-07-01

    Intracellular bacterial pathogens probably arose when their ancestor adapted from a free-living environment to an intracellular one, leading to clonal bacteria with smaller genomes and less sources of genetic plasticity. Still, this plasticity is needed to respond to the challenges posed by the host. Members of the Brucella genus are facultative-extracellular intracellular bacteria responsible for causing brucellosis in a variety of mammals. The various species keep different host preferences, virulence, and zoonotic potential despite having 97-99% similarity at genome level. Here, we describe elements of genetic variation in Brucella ceti isolated from wildlife dolphins inhabiting the Pacific Ocean and the Mediterranean Sea. Comparison with isolates obtained from marine mammals from the Atlantic Ocean and the broader Brucella genus showed distinctive traits according to oceanic distribution and preferred host. Marine mammal isolates display genetic variability, represented by an important number of IS711 elements as well as specific IS711 and SNPs genomic distribution clustering patterns. Extensive pseudogenization was found among isolates from marine mammals as compared with terrestrial ones, causing degradation in pathways related to energy, transport of metabolites, and regulation/transcription. Brucella ceti isolates infecting particularly dolphin hosts, showed further degradation of metabolite transport pathways as well as pathways related to cell wall/membrane/envelope biogenesis and motility. Thus, gene loss through pseudogenization is a source of genetic variation in Brucella, which in turn, relates to adaptation to different hosts. This is relevant to understand the natural history of bacterial diseases, their zoonotic potential, and the impact of human interventions such as domestication. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  16. Determination of distribution pattern of the heavy metal concentrations in the potable network of Gachsaran by Geographical Information System (GIS

    Directory of Open Access Journals (Sweden)

    G Paraham

    2013-12-01

    . Methods: In this descriptive, cross-sectional study, samples were taken from11 spots of the drinking water distribution network and tested for concentration of 10 metals by Inductivity Coupled Ions Plasma (ICP method in summer of 2010. The research data were compared with national and international water standards. Then the distribution map of heavy metals concentrations in the drinking water wells of the region was prepared by using the Geographical Information System (GIS software. Data were analyzed by the Kruskal-Wallis tests. Results: In all samples, the average concentration of heavy metals were: Arsenic 0.54, Cadmium 0.05, Zinc 55.9, Lead 0.18, Copper .82, Chromium 1.6, Barium 36.5, Selenium0.5, Mercury 0.1 and Silver 0.05 micrograms per liter and was less than the water quality standard. Conclusion: Based on the results obtained, it can be concluded that concentrations of heavy metals in Gachsaran’s drinking water distribution network are not higher than national and international standards and therefore not harmful for people. Key words: Heavy metals, Distribution network, Gachsaran, geographical information system (GIS

  17. A Heterogeneous Distributed Virtual Geographic Environment—Potential Application in Spatiotemporal Behavior Experiments

    Directory of Open Access Journals (Sweden)

    Shen Shen

    2018-02-01

    Full Text Available Due to their strong immersion and real-time interactivity, helmet-mounted virtual reality (VR devices are becoming increasingly popular. Based on these devices, an immersive virtual geographic environment (VGE provides a promising method for research into crowd behavior in an emergency. However, the current cheaper helmet-mounted VR devices are not popular enough, and will continue to coexist with personal computer (PC-based systems for a long time. Therefore, a heterogeneous distributed virtual geographic environment (HDVGE could be a feasible solution to the heterogeneous problems caused by various types of clients, and support the implementation of spatiotemporal crowd behavior experiments with large numbers of concurrent participants. In this study, we developed an HDVGE framework, and put forward a set of design principles to define the similarities between the real world and the VGE. We discussed the HDVGE architecture, and proposed an abstract interaction layer, a protocol-based interaction algorithm, and an adjusted dead reckoning algorithm to solve the heterogeneous distributed problems. We then implemented an HDVGE prototype system focusing on subway fire evacuation experiments. Two types of clients are considered in the system: PC, and all-in-one VR. Finally, we evaluated the performances of the prototype system and the key algorithms. The results showed that in a low-latency local area network (LAN environment, the prototype system can smoothly support 90 concurrent users consisting of PC and all-in-one VR clients. HDVGE provides a feasible solution for studying not only spatiotemporal crowd behaviors in normal conditions, but also evacuation behaviors in emergency conditions such as fires and earthquakes. HDVGE could also serve as a new means of obtaining observational data about individual and group behavior in support of human geography research.

  18. Abundance and size distribution of the sacoglossan Elysia viridis on co-occurring algal hosts on the Swedish west coast.

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    Finn A Baumgartner

    Full Text Available Sacoglossans are specialized marine herbivores that tend to have a close evolutionary relationship with their macroalgal hosts, but the widely distributed species Elysia viridis can associate with several algal species. However, most previous investigations on the field abundance and size distribution of E. viridis have focussed on Codium spp. in the British Isles, and algae from this genus are considered superior hosts for E. viridis. In the present study, we investigated the abundance and size distribution of E. viridis on 6 potential host algae with differing morphologies (the septate species Cladophora sericea, Cladophora rupestris, Chaetomorpha melagonium, and Ceramium virgatum, as well as the siphonaceous species Codium fragile and Bryopsis sp. at 2 sites on the Swedish west coast over the course of a year. In spring, slugs were almost absent from all algal hosts. In summer and autumn, E. viridis consistently occurred on several of the algal species at both sites. The highest number of small E. viridis were found on C. sericea, intermediate numbers of significantly larger E. viridis were found on C. rupestris, while fewer, intermediate sized animals were found on C. fragile. Throughout the study period, only a few E. viridis individuals were found on C. melagonium, Bryopsis sp., and C. virgatum. Our results indicate that E. viridis is an annual species in Sweden, capable of exploiting co-occurring congeneric and intergeneric algal hosts with differing morphologies. These results corroborate previous findings that E. viridis can exploit several different algal species, but does not indicate that C. fragile is a superior host.

  19. A novel approach to parasite population genetics: experimental infection reveals geographic differentiation, recombination and host-mediated population structure in Pasteuria ramosa, a bacterial parasite of Daphnia.

    Science.gov (United States)

    Andras, J P; Ebert, D

    2013-02-01

    The population structure of parasites is central to the ecology and evolution of host-parasite systems. Here, we investigate the population genetics of Pasteuria ramosa, a bacterial parasite of Daphnia. We used natural P. ramosa spore banks from the sediments of two geographically well-separated ponds to experimentally infect a panel of Daphnia magna host clones whose resistance phenotypes were previously known. In this way, we were able to assess the population structure of P. ramosa based on geography, host resistance phenotype and host genotype. Overall, genetic diversity of P. ramosa was high, and nearly all infected D. magna hosted more than one parasite haplotype. On the basis of the observation of recombinant haplotypes and relatively low levels of linkage disequilibrium, we conclude that P. ramosa engages in substantial recombination. Isolates were strongly differentiated by pond, indicating that gene flow is spatially restricted. Pasteuria ramosa isolates within one pond were segregated completely based on the resistance phenotype of the host-a result that, to our knowledge, has not been previously reported for a nonhuman parasite. To assess the comparability of experimental infections with natural P. ramosa isolates, we examined the population structure of naturally infected D. magna native to one of the two source ponds. We found that experimental and natural infections of the same host resistance phenotype from the same source pond were indistinguishable, indicating that experimental infections provide a means to representatively sample the diversity of P. ramosa while reducing the sampling bias often associated with studies of parasite epidemics. These results expand our knowledge of this model parasite, provide important context for the large existing body of research on this system and will guide the design of future studies of this host-parasite system. © 2012 Blackwell Publishing Ltd.

  20. Predicting the geographical distribution of two invasive termite species from occurrence data.

    Science.gov (United States)

    Tonini, Francesco; Divino, Fabio; Lasinio, Giovanna Jona; Hochmair, Hartwig H; Scheffrahn, Rudolf H

    2014-10-01

    Predicting the potential habitat of species under both current and future climate change scenarios is crucial for monitoring invasive species and understanding a species' response to different environmental conditions. Frequently, the only data available on a species is the location of its occurrence (presence-only data). Using occurrence records only, two models were used to predict the geographical distribution of two destructive invasive termite species, Coptotermes gestroi (Wasmann) and Coptotermes formosanus Shiraki. The first model uses a Bayesian linear logistic regression approach adjusted for presence-only data while the second one is the widely used maximum entropy approach (Maxent). Results show that the predicted distributions of both C. gestroi and C. formosanus are strongly linked to urban development. The impact of future scenarios such as climate warming and population growth on the biotic distribution of both termite species was also assessed. Future climate warming seems to affect their projected probability of presence to a lesser extent than population growth. The Bayesian logistic approach outperformed Maxent consistently in all models according to evaluation criteria such as model sensitivity and ecological realism. The importance of further studies for an explicit treatment of residual spatial autocorrelation and a more comprehensive comparison between both statistical approaches is suggested.

  1. Optimizing Geographic Allotment of Photovoltaic Capacity in a Distributed Generation Setting: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Urquhart, B.; Sengupta, M.; Keller, J.

    2012-09-01

    A multi-objective optimization was performed to allocate 2MW of PV among four candidate sites on the island of Lanai such that energy was maximized and variability in the form of ramp rates was minimized. This resulted in an optimal solution set which provides a range of geographic allotment alternatives for the fixed PV capacity. Within the optimal set, a tradeoff between energy produced and variability experienced was found, whereby a decrease in variability always necessitates a simultaneous decrease in energy. A design point within the optimal set was selected for study which decreased extreme ramp rates by over 50% while only decreasing annual energy generation by 3% over the maximum generation allocation. To quantify the allotment mix selected, a metric was developed, called the ramp ratio, which compares ramping magnitude when all capacity is allotted to a single location to the aggregate ramping magnitude in a distributed scenario. The ramp ratio quantifies simultaneously how much smoothing a distributed scenario would experience over single site allotment and how much a single site is being under-utilized for its ability to reduce aggregate variability. This paper creates a framework for use by cities and municipal utilities to reduce variability impacts while planning for high penetration of PV on the distribution grid.

  2. The Geographic Distribution of Liver Cancer in Canada Does Not Associate with Cyanobacterial Toxin Exposure

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    Meaghan A. Labine

    2015-11-01

    Full Text Available Background: The incidence of liver cancer has been increasing in Canada over the past decade, as has cyanobacterial contamination of Canadian freshwater lakes and drinking water sources. Cyanotoxins released by cyanobacteria have been implicated in the pathogenesis of liver cancer. Objective: To determine whether a geographic association exists between liver cancer and surrogate markers of cyanobacterial contamination of freshwater lakes in Canada. Methods: A negative binomial regression model was employed based on previously identified risk factors for liver cancer. Results: No association existed between the geographic distribution of liver cancer and surrogate markers of cyanobacterial contamination. As predicted, significant associations existed in areas with a high prevalence of hepatitis B virus infection, large immigrant populations and urban residences. Discussion and Conclusions: The results of this study suggest that cyanobacterial contamination of freshwater lakes does not play an important role in the increasing incidence of liver cancer in Canada.

  3. Population structure and virulence gene profiles of Streptococcus agalactiae collected from different hosts worldwide.

    Science.gov (United States)

    Morach, Marina; Stephan, Roger; Schmitt, Sarah; Ewers, Christa; Zschöck, Michael; Reyes-Velez, Julian; Gilli, Urs; Del Pilar Crespo-Ortiz, María; Crumlish, Margaret; Gunturu, Revathi; Daubenberger, Claudia A; Ip, Margaret; Regli, Walter; Johler, Sophia

    2018-03-01

    Streptococcus agalactiae is a leading cause of morbidity and mortality among neonates and causes severe infections in pregnant women and nonpregnant predisposed adults, in addition to various animal species worldwide. Still, information on the population structure of S. agalactiae and the geographical distribution of different clones is limited. Further data are urgently needed to identify particularly successful clones and obtain insights into possible routes of transmission within one host species and across species borders. We aimed to determine the population structure and virulence gene profiles of S. agalactiae strains from a diverse set of sources and geographical origins. To this end, 373 S. agalactiae isolates obtained from humans and animals from five different continents were typed by DNA microarray profiling. A total of 242 different S. agalactiae strains were identified and further analyzed. Particularly successful clonal lineages, hybridization patterns, and strains were identified that were spread across different continents and/or were present in more than one host species. In particular, several strains were detected in both humans and cattle, and several canine strains were also detected in samples from human, bovine, and porcine hosts. The findings of our study suggest that although S. agalactiae is well adapted to various hosts including humans, cattle, dogs, rodents, and fish, interspecies transmission is possible and occurs between humans and cows, dogs, and rabbits. The virulence and resistance gene profiles presented enable new insights into interspecies transmission and make a crucial contribution to the identification of suitable targets for therapeutic agents and vaccines.

  4. Characterization of Sunn hemp begomovirus and its geographical ...

    African Journals Online (AJOL)

    Thus, it is concluded that the recombinant CP genes related to begomoviruses are evolved from the Indian isolates, causing broad host specificity and molecular diversity among the related begomoviruses across the geographical limits of Southeast Asia. Keywords: Begomovirus, sunn hemp, coat protein, recombination, ...

  5. Development of peptide-based lineage-specific serology for chronic Chagas disease: geographical and clinical distribution of epitope recognition.

    Directory of Open Access Journals (Sweden)

    Tapan Bhattacharyya

    2014-05-01

    Full Text Available BACKGROUND: Chagas disease, caused by infection with the protozoan Trypanosoma cruzi, remains a serious public health issue in Latin America. Genetically diverse, the species is sub-divided into six lineages, known as TcI-TcVI, which have disparate geographical and ecological distributions. TcII, TcV, and TcVI are associated with severe human disease in the Southern Cone countries, whereas TcI is associated with cardiomyopathy north of the Amazon. T. cruzi persists as a chronic infection, with cardiac and/or gastrointestinal symptoms developing years or decades after initial infection. Identifying an individual's history of T. cruzi lineage infection directly by genotyping of the parasite is complicated by the low parasitaemia and sequestration in the host tissues. METHODOLOGY/PRINCIPAL FINDINGS: We have applied here serology against lineage-specific epitopes of the T. cruzi surface antigen TSSA, as an indirect approach to allow identification of infecting lineage. Chagasic sera from chronic patients from a range of endemic countries were tested by ELISA against synthetic peptides representing lineage-specific TSSA epitopes bound to avidin-coated ELISA plates via a biotin labelled polyethylene glycol-glycine spacer to increase rotation and ensure each amino acid side chain could freely interact with their antibodies. 79/113 (70% of samples from Brazil, Bolivia, and Argentina recognised the TSSA epitope common to lineages TcII/TcV/TcVI. Comparison with clinical information showed that a higher proportion of Brazilian TSSApep-II/V/VI responders had ECG abnormalities than non-responders (38% vs 17%; p<0.0001. Among northern chagasic sera 4/20 (20% from Ecuador reacted with this peptide; 1/12 Venezuelan and 1/34 Colombian samples reacted with TSSApep-IV. In addition, a proposed TcI-specific epitope, described elsewhere, was demonstrated here to be highly conserved across lineages and therefore not applicable to lineage-specific serology. CONCLUSIONS

  6. Development of peptide-based lineage-specific serology for chronic Chagas disease: geographical and clinical distribution of epitope recognition.

    Science.gov (United States)

    Bhattacharyya, Tapan; Falconar, Andrew K; Luquetti, Alejandro O; Costales, Jaime A; Grijalva, Mario J; Lewis, Michael D; Messenger, Louisa A; Tran, Trang T; Ramirez, Juan-David; Guhl, Felipe; Carrasco, Hernan J; Diosque, Patricio; Garcia, Lineth; Litvinov, Sergey V; Miles, Michael A

    2014-05-01

    Chagas disease, caused by infection with the protozoan Trypanosoma cruzi, remains a serious public health issue in Latin America. Genetically diverse, the species is sub-divided into six lineages, known as TcI-TcVI, which have disparate geographical and ecological distributions. TcII, TcV, and TcVI are associated with severe human disease in the Southern Cone countries, whereas TcI is associated with cardiomyopathy north of the Amazon. T. cruzi persists as a chronic infection, with cardiac and/or gastrointestinal symptoms developing years or decades after initial infection. Identifying an individual's history of T. cruzi lineage infection directly by genotyping of the parasite is complicated by the low parasitaemia and sequestration in the host tissues. We have applied here serology against lineage-specific epitopes of the T. cruzi surface antigen TSSA, as an indirect approach to allow identification of infecting lineage. Chagasic sera from chronic patients from a range of endemic countries were tested by ELISA against synthetic peptides representing lineage-specific TSSA epitopes bound to avidin-coated ELISA plates via a biotin labelled polyethylene glycol-glycine spacer to increase rotation and ensure each amino acid side chain could freely interact with their antibodies. 79/113 (70%) of samples from Brazil, Bolivia, and Argentina recognised the TSSA epitope common to lineages TcII/TcV/TcVI. Comparison with clinical information showed that a higher proportion of Brazilian TSSApep-II/V/VI responders had ECG abnormalities than non-responders (38% vs 17%; p<0.0001). Among northern chagasic sera 4/20 (20%) from Ecuador reacted with this peptide; 1/12 Venezuelan and 1/34 Colombian samples reacted with TSSApep-IV. In addition, a proposed TcI-specific epitope, described elsewhere, was demonstrated here to be highly conserved across lineages and therefore not applicable to lineage-specific serology. These results demonstrate the considerable potential for synthetic

  7. Tracking the evolutionary history of Cortinarius species in section Calochroi, with transoceanic disjunct distributions

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    Ammirati Joseph

    2011-07-01

    Full Text Available Abstract Background Cortinarius species in section Calochroi display local, clinal and circumboreal patterns of distribution across the Northern Hemisphere where these ectomycorrhizal fungi occur with host trees throughout their geographical range within a continent, or have disjunct intercontinental distributions, the origins of which are not understood. We inferred evolutionary histories of four species, 1 C. arcuatorum, 2 C. aureofulvus, 3 C. elegantior and 4 C. napus, from populations distributed throughout the Old World, and portions of the New World (Central- and North America based on genetic variation of 154 haplotype internal transcribed spacer (ITS sequences from 83 population samples. By describing the population structure of these species across their geographical distribution, we attempt to identify their historical migration and patterns of diversification. Results Models of population structure from nested clade, demographic and coalescent-based analyses revealed genetically differentiated and geographically structured haplotypes in C. arcuatorum and C. elegantior, while C. aureofulvus showed considerably less population structure and C. napus lacked sufficient genetic differentiation to resolve any population structure. Disjunct populations within C. arcuatorum, C. aureofulvus and C. elegantior show little or no morphological differentiation, whereas in C. napus there is a high level of homoplasy and phenotypic plasticity for veil and lamellae colour. The ITS sequences of the type specimens of C. albobrunnoides and C. albobrunnoides var. violaceovelatus were identical to one another and are treated as one species with a wider range of geographic distribution under C. napus. Conclusions Our results indicate that each of the Calochroi species has undergone a relatively independent evolutionary history, hypothesised as follows: 1 a widely distributed ancestral population of C. arcuatorum diverged into distinctive sympatric

  8. Geographical data structures supporting regional analysis

    International Nuclear Information System (INIS)

    Edwards, R.G.; Durfee, R.C.

    1978-01-01

    In recent years the computer has become a valuable aid in solving regional environmental problems. Over a hundred different geographic information systems have been developed to digitize, store, analyze, and display spatially distributed data. One important aspect of these systems is the data structure (e.g. grids, polygons, segments) used to model the environment being studied. This paper presents eight common geographic data structures and their use in studies of coal resources, power plant siting, population distributions, LANDSAT imagery analysis, and landuse analysis

  9. Plasticity in host utilization by two host-associated populations of Aphis gossypii Glover.

    Science.gov (United States)

    Barman, A K; Gadhave, K R; Dutta, B; Srinivasan, R

    2018-06-01

    Biological and morphological plasticity in polyphagous insect herbivores allow them to exploit diverse host plant species. Geographical differences in resource availability can lead to preferential host exploitation and result in inconsistent host specialization. Biological and molecular data provide insights into specialization and plasticity of such herbivore populations. In agricultural landscapes, Aphis gossypii encounters several crop and non-crop hosts, which exist in temporal and spatial proximity. We investigated the host-specialization of two A. gossypii host-associated populations (HAPs), which were field collected from cotton and squash (cotton-associated population and melon-associated population), and later maintained separately in the greenhouse. The two aphid populations were exposed to seven plant species (cotton, okra, watermelon, squash, cucumber, pigweed, and morning glory), and evaluated for their host utilization plasticity by estimating aphid's fitness parameters (nymphal period, adult period, fecundity, and intrinsic rate of increase). Four phenotypical characters (body length, head capsule width, hind tibia length and cornicle length) were also measured from the resulting 14 different HAP × host plant combinations. Phylogenetic analysis of mitochondrial COI sequences showed no genetic variation between the two HAPs. Fitness parameters indicated a significant variation between the two aphid populations, and the variation was influenced by host plants. The performance of melon-aphids was poor (up to 89% reduction in fecundity) on malvaceous hosts, cotton and okra. However, cotton-aphids performed better on cucurbitaceous hosts, squash and watermelon (up to 66% increased fecundity) compared with the natal host, cotton. Both HAPs were able to reproduce on two weed hosts. Cotton-aphids were smaller than melon-aphids irrespective of their host plants. Results from this study suggest that the two HAPs in the study area do not have strict host

  10. Geographic variation in host fish use and larval metamorphosis for the endangered dwarf wedgemussel

    Science.gov (United States)

    White, Barbara (St. John); Ferreri, C. Paola; Lellis, William A.; Wicklow, Barry J.; Cole, Jeffrey C.

    2017-01-01

    Host fishes play a crucial role in survival and dispersal of freshwater mussels (Unionoida), particularly rare unionids at conservation risk. Intraspecific variation in host use is not well understood for many mussels, including the endangered dwarf wedgemussel (Alasmidonta heterodon) in the USA.Host suitability of 33 fish species for dwarf wedgemussel glochidia (larvae) from the Delaware and Connecticut river basins was tested in laboratory experiments over 9 years. Relative suitability of three different populations of a single host fish, the tessellated darter (Etheostoma olmstedi), from locations in the Connecticut, Delaware, and Susquehanna river basins, was also tested.Connecticut River basin A. heterodon metamorphosed into juvenile mussels on tessellated darter, slimy sculpin (Cottus cognatus), and Atlantic salmon (Salmo salar) parr. Delaware River basin mussels metamorphosed using these three species, as well as brown trout (Salmo trutta), banded killifish (Fundulus diaphanus), mottled sculpin (Cottus bairdii), striped bass (Morone saxatilis), and shield darter (Percina peltata). Atlantic salmon, striped bass, and sculpins were highly effective hosts, frequently generating 5+ juveniles per fish (JPF) and metamorphosis success (MS; proportion of attaching larvae that successfully metamorphose) ≥ 0.4, and producing juveniles in repeated trials.In experiments on tessellated darters, mean JPF and MS values decreased as isolation between the mussel source (Connecticut River) and each fish source increased; mean JPF = 10.45, 6.85, 4.14, and mean MS = 0.50, 0.41, and 0.34 in Connecticut, Delaware, and Susquehanna river darters, respectively. Host suitability of individual darters was highly variable (JPF = 2–11; MS = 0.20–1.0).The results show that mussel–host fish compatibility in A. heterodon differs among Atlantic coastal rivers, and suggest that hosts including anadromous Atlantic salmon and striped bass may help sustain A. heterodon in parts of

  11. Geographical distribution of β-globin gene mutations in Syria.

    Science.gov (United States)

    Murad, Hossam; Moasses, Faten; Dabboul, Amir; Mukhalalaty, Yasser; Bakoor, Ahmad Omar; Al-Achkar, Walid; Jarjour, Rami A

    2018-04-11

    Objectives β-Thalassemia disease is caused by mutations in the β-globin gene. This is considered as one of the common genetic disorders in Syria. The aim of this study was to identify the geographical distribution of the β-thalassemia mutations in Syria. Methods β-Globin gene mutations were characterized in 636 affected patients and 94 unrelated carriers using the amplification refractory mutations system-polymerase chain reaction technique and DNA sequencing. Results The study has revealed the presence of 38 β-globin gene mutations responsible for β-thalassemia in Syria. Important differences in regional distribution were observed. IVS-I.110 [G > A] (22.2%), IVS-I.1 [G > A] (17.8%), Cd 39 [C > T] (8.2%), IVS-II.1 [G > A] (7.6%), IVS-I.6 [T > C] (7.1%), Cd 8 [-AA] (6%), Cd 5 [-CT] (5.6%) and IVS-I.5 [G > C] (4.1%) were the eight predominant mutations found in our study. The coastal region had higher relative frequencies (37.9 and 22%) than other regions. A clear drift in the distribution of the third common Cd 39 [C > T] mutation in the northeast region (34.8%) to the northwest region (2.5%) was noted, while the IVS-I.5 [G > C] mutation has the highest prevalence in north regions. The IVS-I.6 [T > C] mutation had a distinct frequency in the middle region. Ten mutations -86 [C > G], -31 [A > G], -29 [A > G], 5'UTR; +22 [G > A], CAP + 1 [A > C], Codon 5/6 [-TG], IVS-I (-3) or codon 29 [C > T], IVS-I.2 [T > A], IVS-I.128 [T > G] and IVS-II.705 [T > G] were found in Syria for the first time. Conclusions These data will significantly facilitate the population screening, genetic counseling and prenatal diagnosis in Syrian population.

  12. Geographic distance and ecosystem size determine the distribution of smallest protists in lacustrine ecosystems.

    Science.gov (United States)

    Lepère, Cécile; Domaizon, Isabelle; Taïb, Najwa; Mangot, Jean-François; Bronner, Gisèle; Boucher, Delphine; Debroas, Didier

    2013-07-01

    Understanding the spatial distribution of aquatic microbial diversity and the underlying mechanisms causing differences in community composition is a challenging and central goal for ecologists. Recent insights into protistan diversity and ecology are increasing the debate over their spatial distribution. In this study, we investigate the importance of spatial and environmental factors in shaping the small protists community structure in lakes. We analyzed small protists community composition (beta-diversity) and richness (alpha-diversity) at regional scale by different molecular methods targeting the gene coding for 18S rRNA gene (T-RFLP and 454 pyrosequencing). Our results show a distance-decay pattern for rare and dominant taxa and the spatial distribution of the latter followed the prediction of the island biogeography theory. Furthermore, geographic distances between lakes seem to be the main force shaping the protists community composition in the lakes studied here. Finally, the spatial distribution of protists was discussed at the global scale (11 worldwide distributed lakes) by comparing these results with those present in the public database. UniFrac analysis showed 18S rRNA gene OTUs compositions significantly different among most of lakes, and this difference does not seem to be related to the trophic status. © 2013 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  13. Geographical distribution of salmonella infected pig, cattle and sheep herds in Sweden 1993-2010

    Directory of Open Access Journals (Sweden)

    Skog Lars

    2011-10-01

    Full Text Available Abstract Background The Swedish salmonella control programme covers the entire production chain, from feed to food. All salmonella serotypes are notifiable. On average, less than 20 cases of salmonella in food-producing animals are reported every year. In some situations, the cases would be expected to cluster geographically. The aim of this study was to illustrate the geographic distribution of the salmonella cases detected in pigs, cattle and sheep. Methods Data on all herds with pigs, cattle and sheep found to be infected with salmonella during the time period from 1993 to 2010 were obtained from the Swedish Board of Agriculture. Using the ArcGIS software, various maps were produced of infected herds, stratified on animal species as well as salmonella serotype. Based on ocular inspection of all maps, some were collapsed and some used separately. Data were also examined for temporal trends. Results No geographical clustering was observed for ovine or porcine cases. Cattle herds infected with Salmonella Dublin were mainly located in the southeast region and cattle herds infected with Salmonella Typhimurium in the most southern part of the country. Some seasonal variation was seen in cattle, but available data was not sufficient for further analyses. Conclusions Analyses of data on salmonella infected herds revealed some spatial and temporal patterns for salmonella in cattle. However, despite using 18 years' of data, the number of infected herds was too low for any useful statistical analyses.

  14. Distribution, habitats and role as intermediate host of the freshwater snail, Bulinus forskalii, in South Africa

    Directory of Open Access Journals (Sweden)

    K.N. De Kock

    2005-09-01

    Full Text Available This paper focuses on the geographical distribution and habitats of Bulinus forskalii, the snail intermediate host of the conical fluke of equids, Gastrodiscus aegyptiacus as reflected by the 1 209 samples in the database of the National Freshwater Snail Collection of South Africa. The 362 different loci on record represent an extensive distribution in KwaZulu-Natal Province, the Limpopo Province, the coastal areas of the Eastern Cape Province and the south-eastern part of the North West Province. Although it was recorded from all types of water-body represented in the database, the highest percentages of samples were recovered from dams (30.4 % and brooks (28.2 %. The majority of samples came from perennial habitats (59.1%, 60.7% from habitats with standing water, 54.0 % from habitats with clear water and 71.8 % from habitats of which the water was described as fresh. The majority of samples (39.5 % were collected in habitats of which the substratum was recorded as muddy. The highest percentage of samples, by far (81.5 %, was collected in habitats that fell within the mean yearly temperature interval ranging from 15-20 °C. An integrated decision tree constructed from the data in the database indicated that temperature and type of water-body played a decisive role in determining the presence of B. forskalii in a given area. The results of experimental exposure to miracidia of a local strain of both Schistosoma haematobium and Schistosoma mattheei in the laboratory indicated that a local strain of B. forskalii was incompatible with both these strains of parasite. Research to clarify the role of B. forskalii in the transmission of both Calicophoron microbothrium and G. aegyptiacus in South Africa, is recommended.

  15. Positive identity entry control system with geographically distributed portals and enrollment stations

    International Nuclear Information System (INIS)

    McIntire, J.M.

    1985-01-01

    A positive identity entry control system using distributed processing to allow reliable geographically separated portals and enrollment stations has been installed and is fully operational at a large area DOE site. Identity verification requires a credential, a memorized number and measurement of a physical characteristic of the user. Additionally, all portal activity is monitored by guards. The portal system is dual redundant such that no single point failure will shut down operations. Each portal site maintains its own subset of the master data base so off-site failure of the central data base manager or its communication links will not significantly affect local portal activity. The system is suitable for installations with large populations requiring access control at several remote sites scattered over a large area

  16. Host specialization in ticks and transmission of tick-borne diseases: a review.

    Science.gov (United States)

    McCoy, Karen D; Léger, Elsa; Dietrich, Muriel

    2013-01-01

    Determining patterns of host use, and the frequency at which these patterns change, are of key importance if we are to understand tick population dynamics, the evolution of tick biodiversity, and the circulation and evolution of associated pathogens. The question of whether ticks are typically host specialists or host generalists has been subject to much debate over the last half-century. Indeed, early research proposed that morphological diversity in ticks was linked to host specific adaptations and that most ticks were specialists. Later work disputed this idea and suggested that ticks are largely limited by biogeographic conditions and tend to use all locally available host species. The work presented in this review suggests that the actual answer likely lies somewhere between these two extremes. Although recent observational studies support the view that phylogenetically diverse host species share ticks when found on similar ecological ranges, theory on host range evolution predicts that host specialization should evolve in ticks given their life history characteristics. Contemporary work employing population genetic tools to examine host-associated population structure in several tick systems support this prediction and show that simple species records are not enough to determine whether a parasite is a true host generalist; host specialization does evolve in ticks at local scales, but may not always lead to speciation. Ticks therefore seem to follow a pattern of being global generalists, local specialists. Given this, the notion of host range needs to be modified from an evolutionary perspective, where one simply counts the number of hosts used across the geographic distribution, to a more ecological view, where one considers host use at a local scale, if we are to better understand the circulation of tick-borne pathogens and exposure risks for humans and livestock.

  17. An Ambient Intelligence Framework for the Provision of Geographically Distributed Multimedia Content to Mobility Impaired Users

    Science.gov (United States)

    Kehagias, Dionysios D.; Giakoumis, Dimitris; Tzovaras, Dimitrios; Bekiaris, Evangelos; Wiethoff, Marion

    This chapter presents an ambient intelligence framework whose goal is to facilitate the information needs of mobility impaired users on the move. This framework couples users with geographically distributed services and the corresponding multimedia content, enabling access to context-sensitive information based on user geographic location and the use case under consideration. It provides a multi-modal facility that is realized through a set of mobile devices and user interfaces that address the needs of ten different types of user impairments. The overall ambient intelligence framework enables users who are equipped with mobile devices to access multimedia content in order to undertake activities relevant to one or more of the following domains: transportation, tourism and leisure, personal support services, work, business, education, social relations and community building. User experience is being explored against those activities through a specific usage scenario.

  18. Prevalence and geographic distribution of herniated intervertebral disc in Korean 19-year-old male from 2008 to 2009: a study based on Korean conscription -national and geographic prevalence of herniated intervertebral disc in Korean 19YO male-.

    Science.gov (United States)

    Lee, Sang Hun; Oh, Chang Hyun; Yoon, Seung Hwan; Park, Hyeong-chun; Park, Chong Oon

    2013-09-01

    This study was to determine the prevalence of herniated intervertebral disc (HIVD) among Korean 19-year-old male in a large national sample and to compare the prevalence across geographic regions based on the data of conscription. We analyzed the conscription data of 615508 cases who were 19-year-old male, given an examination for conscription at nationwide Korean Military Manpower Administration from January 2008 to December 2009. Prevalence was determined by dividing the number of cases by the number of persons enrolled for 2 years. The analyses included of a cross-tabulations and nonparametric chi-square to compare the prevalence according to geographic region, disc severity, and conscription year. The prevalence of HIVD among 19-year-old male was 0.47%. Seoul had the highest prevalence of HIVD (total HIVD was 0.60%, and severe HIVD was 0.44%). The prevalence of HIVD was lower in Jeollabuk- do and Jeollanam-do (total HIVD was 0.25-0.27%, and severe HIVD was 0.16-0.17%). Annual prevalence of HIVD was slightly decreased in 2009, but geographic distribution annually was not different. In Korean 19-year-old male, the national prevalence of adolescent HIVD was 0.60%, but different geographic distribution was observed. It is quite possible that secondary contributing factor(s) interfere with the different geographic prevalence of HIVD.

  19. Diversity of Blastocystis subtypes in dogs in different geographical settings

    DEFF Research Database (Denmark)

    Wang, Wenqi; Cuttell, Leigh; Bielefeldt-Ohmann, Helle

    2013-01-01

    Background: Blastocystis is a ubiquitous, globally distributed intestinal protist infecting humans and a wide range of animals. Several studies have shown that Blastocystis is a potentially zoonotic parasite. A 1996 study reported a 70% Blastocystis prevalence in Brisbane pound dogs while another...... study found that pet dogs/cats of 11 symptomatic Blastocystis infected patients harboured at least one Blastocystis subtype (ST) in common with the patient. These results raised the possibility that dogs might be natural hosts of Blastocystis. In this study, we aimed to investigate this hypothesis...... by estimating the prevalence of Blastocystis carriage and characterising the diversity of STs in dogs from three different environmental settings and comparing these STs with the range that humans harbour. Methods: Two hundred and forty faecal samples from dogs from three different geographical regions...

  20. [The genetic diversity and homology of Anabaena azollae and its host plant (Azolla) based on rapd analysis].

    Science.gov (United States)

    Chen, Jian; Zheng, Wei-wen; Xu, Guo-zhong; Song, Tie-ying; Tang, Long-fei

    2002-01-01

    Symbiotic Anabeana azollae and its host plant Anabeana-free Azolla were isolated from 16 Azolla accessions representing different Azolla species or geographic origins.DNA polymorphic fragments were obtained by simultaneous RAPD amplification of both symbiont and host. The UPGMA clusters of Anabeana azollae and its host Azolla were established separately based on Dice coefficient caculation and a coordinated relationship was shown between Anabeana azollae and its Azolla host along both individual genetic divergence,but this genetic homology was reduced among different strains within Azolla species while the obvious mutants of Anabeana azollae were detected in some Azolla tested strains collected from different geographic area in the same host species.

  1. The online database MaarjAM reveals global and ecosystemic distribution patterns in arbuscular mycorrhizal fungi (Glomeromycota).

    Science.gov (United States)

    Opik, M; Vanatoa, A; Vanatoa, E; Moora, M; Davison, J; Kalwij, J M; Reier, U; Zobel, M

    2010-10-01

    • Here, we describe a new database, MaarjAM, that summarizes publicly available Glomeromycota DNA sequence data and associated metadata. The goal of the database is to facilitate the description of distribution and richness patterns in this group of fungi. • Small subunit (SSU) rRNA gene sequences and available metadata were collated from all suitable taxonomic and ecological publications. These data have been made accessible in an open-access database (http://maarjam.botany.ut.ee). • Two hundred and eighty-two SSU rRNA gene virtual taxa (VT) were described based on a comprehensive phylogenetic analysis of all collated Glomeromycota sequences. Two-thirds of VT showed limited distribution ranges, occurring in single current or historic continents or climatic zones. Those VT that associated with a taxonomically wide range of host plants also tended to have a wide geographical distribution, and vice versa. No relationships were detected between VT richness and latitude, elevation or vascular plant richness. • The collated Glomeromycota molecular diversity data suggest limited distribution ranges in most Glomeromycota taxa and a positive relationship between the width of a taxon's geographical range and its host taxonomic range. Inconsistencies between molecular and traditional taxonomy of Glomeromycota, and shortage of data from major continents and ecosystems, are highlighted.

  2. Molecular analysis of echinostome metacercariae from their second intermediate host found in a localised geographic region reveals genetic heterogeneity and possible cryptic speciation.

    Directory of Open Access Journals (Sweden)

    Waraporn Noikong

    2014-04-01

    Full Text Available Echinostome metacercariae are the infective stage for humans and animals. The identification of echinostomes has been based until recently on morphology but molecular techniques using sequences of ribosomal RNA and mitochondrial DNA have indicated major clades within the group. In this study we have used the ITS2 region of ribosomal RNA and the ND1 region of mitochondrial DNA to identify metacercariae from snails collected from eight well-separated sites from an area of 4000 km2 in Lamphun Province, Thailand. The derived sequences have been compared to those collected from elsewhere and have been deposited in the nucleotide databases. There were two aims of this study; firstly, to determine the species of echinostome present in an endemic area, and secondly, to assess the intra-specific genetic diversity, as this may be informative with regard to the potential for the development of anthelmintic resistance and with regard to the spread of infection by the definitive hosts. Our results indicate that the most prevalent species are most closely related to E. revolutum, E. trivolvis, E. robustum, E. malayanum and Euparyphium albuferensis. Some sites harbour several species and within a site there could be considerable intra-species genetic diversity. There is no significant geographical structuring within this area. Although the molecular techniques used in this study allowed the assignment of the samples to clades within defined species, however, within these groupings there were significant differences indicating that cryptic speciation may have occurred. The degree of genetic diversity present would suggest the use of targeted regimes designed to minimise the selection of anthelmintic resistance. The apparent lack of geographic structuring is consistent with the transmission of the parasites by the avian hosts.

  3. Diversity and spation distribution of vectors and hosts of T. brucei gambiense in forest zones of Southern Cameroon: Epidemiological implications

    NARCIS (Netherlands)

    Massussi, J.A.; Mbida Mbida, J.A.; Djieto-Lordon, C.; Njiokou, F.; Laveissière, C.; Ploeg, van der J.D.

    2010-01-01

    Host and vector distribution of Trypanosoma brucei gambiense was studied in relation to habitat types and seasons. Six (19.35%) of the 31 mammal species recorded in Bipindi were reservoir hosts. Cercopithecus nictitans was confined to the undisturbed forest and the low intensive shifting cultivation

  4. Genomes of three facultatively symbiotic Frankia sp. strainsreflect host plant biogeography

    Energy Technology Data Exchange (ETDEWEB)

    Normand, Philippe; Lapierre, Pascal; Tisa, Louis S.; Gogarten, J.Peter; Alloisio, Nicole; Bagnarol, Emilie; Bassi, Carla A.; Berry,Alison; Bickhart, Derek M.; Choisne, Nathalie; Couloux, Arnaud; Cournoyer, Benoit; Cruveiller, Stephane; Daubin, Vincent; Demange, Nadia; Francino, M. Pilar; Ggoltsman, Eugene; Huang, Ying; Kopp, Olga; Labarre,Laurent; Lapidus, Alla; Lavire, Celine; Marechal, Joelle; Martinez,Michele; Mastronunzio, Juliana E.; Mullin, Beth; Niemann, James; Pujic,Pierre; Rawnsley, Tania; Rouy, Zoe; Schenowitz, Chantal; Sellstedt,Anita; Tavares, Fernando; Tomkins, Jeffrey P.; Vallenet, David; Valverde,Claudio; Wall, Luis; Wang, Ying; Medigue, Claudine; Benson, David R.

    2006-02-01

    Filamentous actinobacteria from the genus Frankia anddiverse woody trees and shrubs together form N2-fixing actinorhizal rootnodule symbioses that are a major source of new soil nitrogen in widelydiverse biomes 1. Three major clades of Frankia sp. strains are defined;each clade is associated with a defined subset of plants from among theeight actinorhizal plant families 2,3. The evolution arytrajectoriesfollowed by the ancestors of both symbionts leading to current patternsof symbiont compatibility are unknown. Here we show that the competingprocesses of genome expansion and contraction have operated in differentgroups of Frankia strains in a manner that can be related to thespeciation of the plant hosts and their geographic distribution. Wesequenced and compared the genomes from three Frankia sp. strains havingdifferent host plant specificities. The sizes of their genomes variedfrom 5.38 Mbp for a narrow host range strain (HFPCcI3) to 7.50Mbp for amedium host range strain (ACN14a) to 9.08 Mbp for a broad host rangestrain (EAN1pec.) This size divergence is the largest yet reported forsuch closely related bacteria. Since the order of divergence of thestrains is known, the extent of gene deletion, duplication andacquisition could be estimated and was found to be inconcert with thebiogeographic history of the symbioses. Host plant isolation favoredgenome contraction, whereas host plant diversification favored genomeexpansion. The results support the idea that major genome reductions aswell as expansions can occur in facultatively symbiotic soil bacteria asthey respond to new environments in the context of theirsymbioses.

  5. What influences national and foreign physicians' geographic distribution? An analysis of medical doctors' residence location in Portugal.

    Science.gov (United States)

    Russo, Giuliano; Ferrinho, Paulo; de Sousa, Bruno; Conceição, Cláudia

    2012-07-02

    The debate over physicians' geographical distribution has attracted the attention of the economic and public health literature over the last forty years. Nonetheless, it is still to date unclear what influences physicians' location, and whether foreign physicians contribute to fill the geographical gaps left by national doctors in any given country. The present research sets out to investigate the current distribution of national and international physicians in Portugal, with the objective to understand its determinants and provide an evidence base for policy-makers to identify policies to influence it. A cross-sectional study of physicians currently registered in Portugal was conducted to describe the population and explore the association of physician residence patterns with relevant personal and municipality characteristics. Data from the Portuguese Medical Council on physicians' residence and characteristics were analysed, as well as data from the National Institute of Statistics on municipalities' population, living standards and health care network. Descriptive statistics, chi-square tests, negative binomial and logistic regression modelling were applied to determine: (a) municipality characteristics predicting Portuguese and International physicians' geographical distribution, and; (b) doctors' characteristics that could increase the odds of residing outside the country's metropolitan areas. There were 39,473 physicians in Portugal in 2008, 51.1% of whom male, and 40.2% between 41 and 55 years of age. They were predominantly Portuguese (90.5%), with Spanish, Brazilian and African nationalities also represented. Population, Population's Purchasing Power, Nurses per capita and Municipality Development Index (MDI) were the municipality characteristics displaying the strongest association with national physicians' location. For foreign physicians, the MDI was not statistically significant, while municipalities' foreign population applying for residence

  6. What influences national and foreign physicians’ geographic distribution? An analysis of medical doctors’ residence location in Portugal

    Directory of Open Access Journals (Sweden)

    Russo Giuliano

    2012-07-01

    Full Text Available Abstract Background The debate over physicians’ geographical distribution has attracted the attention of the economic and public health literature over the last forty years. Nonetheless, it is still to date unclear what influences physicians’ location, and whether foreign physicians contribute to fill the geographical gaps left by national doctors in any given country. The present research sets out to investigate the current distribution of national and international physicians in Portugal, with the objective to understand its determinants and provide an evidence base for policy-makers to identify policies to influence it. Methods A cross-sectional study of physicians currently registered in Portugal was conducted to describe the population and explore the association of physician residence patterns with relevant personal and municipality characteristics. Data from the Portuguese Medical Council on physicians’ residence and characteristics were analysed, as well as data from the National Institute of Statistics on municipalities’ population, living standards and health care network. Descriptive statistics, chi-square tests, negative binomial and logistic regression modelling were applied to determine: (a municipality characteristics predicting Portuguese and International physicians’ geographical distribution, and; (b doctors’ characteristics that could increase the odds of residing outside the country’s metropolitan areas. Results There were 39,473 physicians in Portugal in 2008, 51.1% of whom male, and 40.2% between 41 and 55 years of age. They were predominantly Portuguese (90.5%, with Spanish, Brazilian and African nationalities also represented. Population, Population’s Purchasing Power, Nurses per capita and Municipality Development Index (MDI were the municipality characteristics displaying the strongest association with national physicians’ location. For foreign physicians, the MDI was not statistically significant

  7. Proterometra epholkos sp. n. (Digenea: Azygiidae) from Terrapin Creek, Alabama, USA: molecular characterization of life cycle, redescription of Proterometra albacauda, and updated lists of host and geographic locality records for Proterometra spp. in North America.

    Science.gov (United States)

    Womble, Matthew R; Orélis-Ribeiro, Raphael; Bullard, Stephen A

    2015-02-01

    localities and hosts concomitant with neotype designations. P. macrostoma seems a repository for conspicuous, furcocystocercous cercariae shed from freshwater prosobranchs in eastern North American rivers and streams. The specific epithet "pinguis" associated with specimens purportedly infecting Esox lucius and deposited by JF Mueller is a nomen nudum. Proterometra guangzhouensis, Proterometra sillagae, Proterometra brachyuran, and Proterometra lamellorchis are incertae sedis. Significant barriers to characterizing biodiversity and distributions (host range and geographic distribution) of Proterometra spp. comprise a paucity of data on adult morphology, dubious species-level identification or a lack of information regarding prosobranch hosts, lack of molecular data for putative comparisons among fluke 'strains' and species as well as between cercariae and adults, lack of consistency in terminology, and indeterminate homology for key morphological features. Uncertainty about the providence and identity of, or absence of, accessioned museum materials of P. macrostoma, Proterometra catenaria, and P. hodgesiana together represent another fundamental problem. The present study comprises the first description of a new species of Proterometra in nearly 20years, first report of a species of the genus from the Coosa River (Mobile-Tensaw River Basin) and from these host species, and first use of molecular sequence data to elucidate a life cycle for a species of Proterometra. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  8. Efficient workload management in geographically distributed data centers leveraging autoregressive models

    Science.gov (United States)

    Altomare, Albino; Cesario, Eugenio; Mastroianni, Carlo

    2016-10-01

    The opportunity of using Cloud resources on a pay-as-you-go basis and the availability of powerful data centers and high bandwidth connections are speeding up the success and popularity of Cloud systems, which is making on-demand computing a common practice for enterprises and scientific communities. The reasons for this success include natural business distribution, the need for high availability and disaster tolerance, the sheer size of their computational infrastructure, and/or the desire to provide uniform access times to the infrastructure from widely distributed client sites. Nevertheless, the expansion of large data centers is resulting in a huge rise of electrical power consumed by hardware facilities and cooling systems. The geographical distribution of data centers is becoming an opportunity: the variability of electricity prices, environmental conditions and client requests, both from site to site and with time, makes it possible to intelligently and dynamically (re)distribute the computational workload and achieve as diverse business goals as: the reduction of costs, energy consumption and carbon emissions, the satisfaction of performance constraints, the adherence to Service Level Agreement established with users, etc. This paper proposes an approach that helps to achieve the business goals established by the data center administrators. The workload distribution is driven by a fitness function, evaluated for each data center, which weighs some key parameters related to business objectives, among which, the price of electricity, the carbon emission rate, the balance of load among the data centers etc. For example, the energy costs can be reduced by using a "follow the moon" approach, e.g. by migrating the workload to data centers where the price of electricity is lower at that time. Our approach uses data about historical usage of the data centers and data about environmental conditions to predict, with the help of regressive models, the values of the

  9. Experimental assemblage of novel plant-herbivore interactions: ecological host shifts after 40 million years of isolation.

    Science.gov (United States)

    Garcia-Robledo, Carlos; Horvitz, Carol C; Kress, W John; Carvajal-Acosta, A Nalleli; Erwin, Terry L; Staines, Charles L

    2017-11-01

    Geographic isolation is the first step in insect herbivore diet specialization. Such specialization is postulated to increase insect fitness, but may simultaneously reduce insect ability to colonize novel hosts. During the Paleocene-Eocene, plants from the order Zingiberales became isolated either in the Paleotropics or in the Neotropics. During the Cretaceous, rolled-leaf beetles diversified in the Neotropics concurrently with Neotropical Zingiberales. Using a community of Costa Rican rolled-leaf beetles and their Zingiberales host plants as study system, we explored if previous geographic isolation precludes insects to expand their diets to exotic hosts. We recorded interactions between rolled-leaf beetles and native Zingiberales by combining DNA barcodes and field records for 7450 beetles feeding on 3202 host plants. To determine phylogenetic patterns of diet expansions, we set 20 field plots including five exotic Zingiberales, recording beetles feeding on these exotic hosts. In the laboratory, using both native and exotic host plants, we reared a subset of insect species that had expanded their diets to the exotic plants. The original plant-herbivore community comprised 24 beetle species feeding on 35 native hosts, representing 103 plant-herbivore interactions. After exotic host plant introduction, 20% of the beetle species expanded their diets to exotic Zingiberales. Insects only established on exotic hosts that belong to the same plant family as their native hosts. Laboratory experiments show that beetles are able to complete development on these novel hosts. In conclusion, rolled-leaf beetles are pre-adapted to expand their diets to novel host plants even after millions of years of geographic isolation.

  10. The spatial distribution of known predictors of autism spectrum disorders impacts geographic variability in prevalence in central North Carolina

    Directory of Open Access Journals (Sweden)

    Hoffman Kate

    2012-10-01

    Full Text Available Abstract Background The causes of autism spectrum disorders (ASD remain largely unknown and widely debated; however, evidence increasingly points to the importance of environmental exposures. A growing number of studies use geographic variability in ASD prevalence or exposure patterns to investigate the association between environmental factors and ASD. However, differences in the geographic distribution of established risk and predictive factors for ASD, such as maternal education or age, can interfere with investigations of ASD etiology. We evaluated geographic variability in the prevalence of ASD in central North Carolina and the impact of spatial confounding by known risk and predictive factors. Methods Children meeting a standardized case definition for ASD at 8 years of age were identified through records-based surveillance for 8 counties biennially from 2002 to 2008 (n=532. Vital records were used to identify the underlying cohort (15% random sample of children born in the same years as children with an ASD, n=11,034, and to obtain birth addresses. We used generalized additive models (GAMs to estimate the prevalence of ASD across the region by smoothing latitude and longitude. GAMs, unlike methods used in previous spatial analyses of ASD, allow for extensive adjustment of individual-level risk factors (e.g. maternal age and education when evaluating spatial variability of disease prevalence. Results Unadjusted maps revealed geographic variation in surveillance-recognized ASD. Children born in certain regions of the study area were up to 1.27 times as likely to be recognized as having ASD compared to children born in the study area as a whole (prevalence ratio (PR range across the study area 0.57-1.27; global P=0.003. However, geographic gradients of ASD prevalence were attenuated after adjusting for spatial confounders (adjusted PR range 0.72-1.12 across the study area; global P=0.052. Conclusions In these data, spatial variation of ASD

  11. About the Geographic Distribution of Economic Science in Asian Russia

    Directory of Open Access Journals (Sweden)

    Alexander Nikolaevich Demyanenko

    2014-12-01

    Full Text Available The article presents the results of empirical studies of modern geographic distribution of economic science in Asian Russia (i. e. three macro-regions of Russia: Far East, Siberia and the Urals Region. The study is based on an original database of articles on Economics and related disciplines which arearranged within the Elibrary platformfor 2005-2013. These articles arewritten by fellows of research organizations that are located in the Asian part of Russia.Statistical analysis of the main indicators of publication activity shows that there are significant differences in the scope, dynamics, and quality of the results of this activity among the research organizations of various types.The authors focused on the territorial structure of the study of the economy defined as a set of scientific centers of varying scale and type, as well as networks of scientific communication.It is revealed that publication activity of economic research institutions in Asian Russia has a high level of spatial concentration and the system of scientific communication, formed by the scientific journals of the region, has a high level of fragmentation

  12. Geographical cost-supply analysis forest biomass for distributed generation in Denmark

    DEFF Research Database (Denmark)

    Möller, Bernd

    2004-01-01

    The article presents a study which uses geographical information system (GIS) to perform cost-supply analysis of wood chips resources for energy production.......The article presents a study which uses geographical information system (GIS) to perform cost-supply analysis of wood chips resources for energy production....

  13. Modelling climate change impact on the spatial distribution of fresh water snails hosting trematodes in Zimbabwe.

    Science.gov (United States)

    Pedersen, Ulrik B; Stendel, Martin; Midzi, Nicholas; Mduluza, Takafira; Soko, White; Stensgaard, Anna-Sofie; Vennervald, Birgitte J; Mukaratirwa, Samson; Kristensen, Thomas K

    2014-12-12

    Freshwater snails are intermediate hosts for a number of trematodes of which some are of medical and veterinary importance. The trematodes rely on specific species of snails to complete their life cycle; hence the ecology of the snails is a key element in transmission of the parasites. More than 200 million people are infected with schistosomes of which 95% live in sub-Saharan Africa and many more are living in areas where transmission is on-going. Human infection with the Fasciola parasite, usually considered more of veterinary concern, has recently been recognised as a human health problem. Many countries have implemented health programmes to reduce morbidity and prevalence of schistosomiasis, and control programmes to mitigate food-borne fascioliasis. As these programmes are resource demanding, baseline information on disease prevalence and distribution becomes of great importance. Such information can be made available and put into practice through maps depicting spatial distribution of the intermediate snail hosts. A biology driven model for the freshwater snails Bulinus globosus, Biomphalaria pfeifferi and Lymnaea natalensis was used to make predictions of snail habitat suitability by including potential underlying environmental and climatic drivers. The snail observation data originated from a nationwide survey in Zimbabwe and the prediction model was parameterised with a high resolution Regional Climate Model. Georeferenced prevalence data on urinary and intestinal schistosomiasis and fascioliasis was used to calibrate the snail habitat suitability predictions to produce binary maps of snail presence and absence. Predicted snail habitat suitability across Zimbabwe, as well as the spatial distribution of snails, is reported for three time slices representative for present (1980-1999) and future climate (2046-2065 and 2080-2099). It is shown from the current study that snail habitat suitability is highly variable in Zimbabwe, with distinct high- and low

  14. Geographic Distribution of Radiologists and Utilization of Teleradiology in Japan: A Longitudinal Analysis Based on National Census Data.

    Science.gov (United States)

    Matsumoto, Masatoshi; Koike, Soichi; Kashima, Saori; Awai, Kazuo

    2015-01-01

    Japan has the most CT and MRI scanners per unit population in the world, and as these technologies spread, their geographic distribution is becoming equalized. In contrast, the number of radiologists per unit population in Japan is the lowest among OECD countries and their geographic distribution is unknown. Likewise, little is known about the use of teleradiology, which can compensate for the uneven distribution of radiologists. Based on the Survey of Physicians, Dentists and Pharmacists and the Static Survey of Medical Institutions by the Ministry of Health, Labour and Welfare, a dataset of radiologists and CT and MRI utilizations in each of Japan's 1811 municipalities was created. The inter-municipality equity of the number of radiologists was evaluated using Gini coefficient. Logistic regression analysis, based on Static Survey data, was performed to evaluate the association between hospital location and teleradiology use. Between 2006 and 2012 the number of radiologists increased by 21.7%, but the Gini coefficient remained unchanged. The number of radiologists per 1,000 CT (MRI) utilizations decreased by 17.9% (1.0%); the number was highest in metropolis and lowest in town/village and the disparity has widened from 1.9 to 2.2 (1.6 to 2.0) times. The number of hospitals and clinics using teleradiology has increased (by 69.6% and 18.1%, respectively). Hospitals located in towns/villages (odds ratio 1.61; 95% confidence interval 1.26-2.07) were more likely to use teleradiology than those in metropolises. Contrary to the CT and MRI distributions, radiologist distribution has not been evened out by the increase in their number; in other words, the distribution of radiologists was not affected by market-derived spatial competition force. As a consequence, the gap of the radiologist shortage between urban and rural areas is increasing. Teleradiology, which is one way to ameliorate this gap, should be encouraged.

  15. Geographic distribution of ebony leaf monkey Trachypithecus auratus (E. Geoffroy Saint-Hilaire, 1812) (Mammalia: Primates: Cercopithecidae)

    OpenAIRE

    Nijman, Vincent

    2000-01-01

    As one of the fundamental units of ecology and biogeography, the geographic distribution of the endemic and threatened ebony leaf monkey Trachypithecus auratus (E. Geoffroy Saint-Hilaire, 1812) on the islands of Java, Bali, and Lombok (Indonesia) has been assessed. All localities where the species has been collected are listed, and forty-two areas (each in itself consisting of numerous smaller sites) where the species has been recorded are discussed. The species occurs in a large variety of f...

  16. Modeling the distribution of Schistosoma mansoni and host snails in Uganda using satellite sensor data and Geographical Information Systems

    DEFF Research Database (Denmark)

    Stensgaard, Anna-Sofie; Jørgensen, A; Kabatereine, N B

    2005-01-01

    The potential value of MODIS satellite sensor data on Normalized Difference Vegetation Index (NDVI) and land surface temperatures (LST) for describing the distribution of the Schistosoma mansoni-"Biomphalaria pfeifferi"/Biomphalaria sudanica parasite-snail system in inland Uganda, were tested...... by developing annual and seasonal composite models, and iteratively analysing for their relationship with parasite and snail distribution. The dry season composite model predicted an endemic area that produced the best fit with the distribution of schools with > or =5% prevalence. NDVI values of 151-174, day...

  17. Geographical Distribution of the Most Frequent Mutations of Familial Mediterranean fever in the World

    Directory of Open Access Journals (Sweden)

    Soraya Hadi

    2016-09-01

    Full Text Available Background and objectives: Familial Mediterranean Fever (FMF is an autosomal recessive disease. Generally, the Mediterranean basin is the region where the first cases of FMF have been identified. The gene responsible for FMF is gene MEFV. Disease occurs due to mutations in the gene MEFV. Our aim was to determine the geographical distribution of the most frequent mutations in Familial Mediterranean Fever Disease in the world. Material and Methods: In this study, databases including Google Scholar, PubMed, Medline, Ovid, IranMedex, Irandoc, SID, Magiran and published papers were searched with no limitation in time. Then, all collected studies without any limitation were assessed to determine relevant studies. At the end, world map of the most frequent mutations of FMF was generated by Geographical Information System (GIS software. Results: Although more than 290 mutations of the MEFV gene have been described, only four mutations (M694V, M694I, V726A, and E148Q were prevalent among patients with FMF. Conclusion: The most frequent mutation associated with FMF mutation is M694V all over the world. E148Q mutation was found to be with mild clinical relevance.

  18. Cryptic host-specific diversity among western hemisphere broomrapes (Orobanche s.l., Orobanchaceae).

    Science.gov (United States)

    Schneider, Adam C; Colwell, Alison E L; Schneeweiss, Gerald M; Baldwin, Bruce G

    2016-11-01

    The broomrapes, Orobanche sensu lato (Orobanchaceae), are common root parasites found across Eurasia, Africa and the Americas. All species native to the western hemisphere, recognized as Orobanche sections Gymnocaulis and Nothaphyllon, form a clade that has a centre of diversity in western North America, but also includes four disjunct species in central and southern South America. The wide ecological distribution coupled with moderate taxonomic diversity make this clade a valuable model system for studying the role, if any, of host-switching in driving the diversification of plant parasites. Two spacer regions of ribosomal nuclear DNA (ITS + ETS), three plastid regions and one low-copy nuclear gene were sampled from 163 exemplars of Orobanche from across the native geographic range in order to infer a detailed phylogeny. Together with comprehensive data on the parasites' native host ranges, associations between phylogenetic lineages and host specificity are tested. Within the two currently recognized species of O. sect. Gymnocaulis, seven strongly supported clades were found. While commonly sympatric, members of these clades each had unique host associations. Strong support for cryptic host-specific diversity was also found in sect. Nothaphyllon, while other taxonomic species were well supported. We also find strong evidence for multiple amphitropical dispersals from central North America into South America. Host-switching is an important driver of diversification in western hemisphere broomrapes, where host specificity has been grossly underestimated. More broadly, host specificity and host-switching probably play fundamental roles in the speciation of parasitic plants. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Predicting the geographic distribution of Lutzomyia longipalpis (Diptera: Psychodidae) and visceral leishmaniasis in the state of Mato Grosso do Sul, Brazil.

    Science.gov (United States)

    Almeida, Paulo Silva de; Sciamarelli, Alan; Batista, Paulo Mira; Ferreira, Ademar Dimas; Nascimento, João; Raizer, Josué; Andrade Filho, José Dilermando; Gurgel-Gonçalves, Rodrigo

    2013-12-01

    To understand the geographic distribution of visceral leishmaniasis (VL) in the state of Mato Grosso do Sul (MS), Brazil, both the climatic niches of Lutzomyia longipalpis and VL cases were analysed. Distributional data were obtained from 55 of the 79 counties of MS between 2003-2012. Ecological niche models (ENM) of Lu. longipalpis and VL cases were produced using the maximum entropy algorithm based on eight climatic variables. Lu. longipalpis showed a wide distribution in MS. The highest climatic suitability for Lu. longipalpis was observed in southern MS. Temperature seasonality and annual mean precipitation were the variables that most influenced these models. Two areas of high climatic suitability for the occurrence of VL cases were predicted: one near Aquidauana and another encompassing several municipalities in the southeast region of MS. As expected, a large overlap between the models for Lu. longipalpis and VL cases was detected. Northern and northwestern areas of MS were suitable for the occurrence of cases, but did not show high climatic suitability for Lu. longipalpis. ENM of vectors and human cases provided a greater understanding of the geographic distribution of VL in MS, which can be applied to the development of future surveillance strategies.

  20. Vascular plants of the Nevada Test Site and Central-Southern Nevada: ecologic and geographic distributions

    Energy Technology Data Exchange (ETDEWEB)

    Beatley, J.C.

    1976-01-01

    The physical environment of the Nevada Test Site and surrounding area is described with regard to physiography, geology, soils, and climate. A discussion of plant associations is given for the Mojave Desert, Transition Desert, and Great Basin Desert. The vegetation of disturbed sites is discussed with regard to introduced species as well as endangered and threatened species. Collections of vascular plants were made during 1959 to 1975. The plants, belonging to 1093 taxa and 98 families are listed together with information concerning ecologic and geographic distributions. Indexes to families, genera, and species are included. (HLW)

  1. Differences in virulence and sporulation of Phytophthora kernoviae isolates originating from two distinct geographical regions

    Science.gov (United States)

    Phytophthora kernoviae has only been isolated from the United Kingdom (U.K.) and New Zealand. To understand what differences may exist between isolates from these two distinct geographical regions, virulence studies on three host plants and sporulation on host leaves were conducted on select isolat...

  2. Geographic Distribution of Chagas Disease Vectors in Brazil Based on Ecological Niche Modeling

    Directory of Open Access Journals (Sweden)

    Rodrigo Gurgel-Gonçalves

    2012-01-01

    Full Text Available Although Brazil was declared free from Chagas disease transmission by the domestic vector Triatoma infestans, human acute cases are still being registered based on transmission by native triatomine species. For a better understanding of transmission risk, the geographic distribution of Brazilian triatomines was analyzed. Sixteen out of 62 Brazilian species that both occur in >20 municipalities and present synanthropic tendencies were modeled based on their ecological niches. Panstrongylus geniculatus and P. megistus showed broad ecological ranges, but most of the species sort out by the biome in which they are distributed: Rhodnius pictipes and R. robustus in the Amazon; R. neglectus, Triatoma sordida, and T. costalimai in the Cerrado; R. nasutus, P. lutzi, T. brasiliensis, T. pseudomaculata, T. melanocephala, and T. petrocchiae in the Caatinga; T. rubrovaria in the southern pampas; T. tibiamaculata and T. vitticeps in the Atlantic Forest. Although most occurrences were recorded in open areas (Cerrado and Caatinga, our results show that all environmental conditions in the country are favorable to one or more of the species analyzed, such that almost nowhere is Chagas transmission risk negligible.

  3. Energy gradients and the geographic distribution of local ant diversity.

    Science.gov (United States)

    Kaspari, Michael; Ward, Philip S; Yuan, May

    2004-08-01

    Geographical diversity gradients, even among local communities, can ultimately arise from geographical differences in speciation and extinction rates. We evaluated three models--energy-speciation, energy-abundance, and area--that predict how geographic trends in net diversification rates generate trends in diversity. We sampled 96 litter ant communities from four provinces: Australia, Madagascar, North America, and South America. The energy-speciation hypothesis best predicted ant species richness by accurately predicting the slope of the temperature diversity curve, and accounting for most of the variation in diversity. The communities showed a strong latitudinal gradient in species richness as well as inter-province differences in diversity. The former vanished in the temperature-diversity residuals, suggesting that the latitudinal gradient arises primarily from higher diversification rates in the tropics. However, inter-province differences in diversity persisted in those residuals--South American communities remained more diverse than those in North America and Australia even after the effects of temperature were removed.

  4. Geographic distribution of selected elements in the livers of polar bears from Greenland, Canada and the United States

    International Nuclear Information System (INIS)

    Rush, Scott A.; Borga, Katrine; Dietz, Rune; Born, Erik W.; Sonne, Christian; Evans, Thomas; Muir, Derek C.G.; Letcher, Robert J.; Norstrom, Ross J.; Fisk, Aaron T.

    2008-01-01

    To assess geographic distributions of elements in the Arctic we compared essential and non-essential elements in the livers of polar bears (Ursus maritimus) collected from five regions within Canada in 2002, in Alaska between 1994 and 1999 and from the northwest and east coasts of Greenland between 1988 and 2000. As, Hg, Pb and Se varied with age, and Co and Zn with gender, which limited spatial comparisons across all populations to Cd, which was highest in Greenland bears. Collectively, geographic relationships appeared similar to past studies with little change in concentration over time in Canada and Greenland for most elements; Hg and Se were higher in some Canadian populations in 2002 as compared to 1982 and 1984. Concentrations of most elements in the polar bears did not exceed toxicity thresholds, although Cd and Hg exceeded levels correlated with the formation of hepatic lesions in laboratory animals. - Geographical trends were observed for a number of elements in livers, including mercury, of polar bears collected across Alaska, Canada and Greenland and were similar to those observed in the early 1980s

  5. Local host adaptation and use of a novel host in the seed beetle Megacerus eulophus.

    Directory of Open Access Journals (Sweden)

    Gisela C Stotz

    Full Text Available Spatial variation in host plant availability may lead to specialization in host use and local host adaptation in herbivorous insects, which may involve a cost in performance on other hosts. We studied two geographically separated populations of the seed beetle Megacerus eulophus (Coleoptera: Bruchidae in central Chile: a population from the host Convolvulus chilensis (in Aucó and a population from C. bonariensis (in Algarrobo. In Aucó C. chilensis is the only host plant, while in Algarrobo both C. bonariensis and C. chilensis are available. We tested local adaptation to these native host plants and its influence on the use of another, exotic host plant. We hypothesized that local adaptation would be verified, particularly for the one-host population (Aucó, and that the Aucó population would be less able to use an alternative, high-quality host. We found evidence of local adaptation in the population from C. chilensis. Thus, when reared on C. chilensis, adults from the C. chilensis population were larger and lived longer than individuals from the C. bonariensis population, while bruchids from the two populations had the same body size and longevity when reared on C. bonariensis. Overall, bruchids from the C. chilensis population showed greater performance traits than those from the C. bonariensis population. There were no differences between the bruchid populations in their ability to use the alternative, exotic host Calystegia sepium, as shown by body size and longevity patterns. Results suggest that differences in local adaptation might be explained by differential host availability in the study populations.

  6. The New World Gibbobruchus Pic (Coleoptera, Chrysomelidae, Bruchinae): description of a new species and phylogenetic insights into the evolution of host associations and biogeography.

    Science.gov (United States)

    Manfio, Daiara; Jorge, Isaac R; Morse, Geoffrey E; Ribeiro-Costa, Cibele S

    2016-04-18

    The seed beetle Gibbobruchus tridentatus Manfio, Jorge & Ribeiro-Costa sp. nov. is described from the Amazon basin in Brazil (Acre) and Ecuador (Napo), and is included in an updated key to the species of Gibbobruchus Pic. This new species and the recently described G. bergamini Manfio & Ribeiro-Costa are incorporated into a phylogenetic reanalysis of the genus and into a comparative analysis of host plant use and biogeography. Species groups previously proposed were supported and the evolutionary history in host plant-use shows Gibbobruchus conserved at tribe level, Cercideae (Caesalpinioideae), with coordination between biogeographic expansion and host genus shifts. Both species, Gibbobruchus tridentatus Manfio, Jorge & Ribeiro-Costa sp. nov. and G. bergamini, were placed within the group scurra (G. tridentatus (G. scurra (G. cavillator+G. bolivianus+G. bergamini))) and supported by one synapomorphy. Additionally, we update geographic distributions and host plant records. Two hosts, Bauhinia argentinensis Burkart and B. tarapotensis Benth. are recorded for the first time as hosts for the genus and for the subfamily.

  7. Host-specificity among abundant and rare taxa in the sponge microbiome.

    Science.gov (United States)

    Reveillaud, Julie; Maignien, Loïs; Murat Eren, A; Huber, Julie A; Apprill, Amy; Sogin, Mitchell L; Vanreusel, Ann

    2014-06-01

    Microbial communities have a key role in the physiology of the sponge host, and it is therefore essential to understand the stability and specificity of sponge-symbiont associations. Host-specific bacterial associations spanning large geographic distance are widely acknowledged in sponges. However, the full spectrum of specificity remains unclear. In particular, it is not known whether closely related sponges host similar or very different microbiota over wide bathymetric and geographic gradients, and whether specific associations extend to the rare members of the sponge microbiome. Using the ultra-deep Illumina sequencing technology, we conducted a comparison of sponge bacterial communities in seven closely related Hexadella species with a well-resolved host phylogeny, as well as of a distantly related sponge Mycale. These samples spanned unprecedentedly large bathymetric (15-960 m) gradients and varying European locations. In addition, this study included a bacterial community analysis of the local background seawater for both Mycale and the widespread deep-sea taxa Hexadella cf. dedritifera. We observed a striking diversity of microbes associated with the sponges, spanning 47 bacterial phyla. The data did not reveal any Hexadella microbiota co-speciation pattern, but confirmed sponge-specific and species-specific host-bacteria associations, even within extremely low abundant taxa. Oligotyping analysis also revealed differential enrichment preferences of closely related Nitrospira members in closely related sponges species. Overall, these results demonstrate highly diverse, remarkably specific and stable sponge-bacteria associations that extend to members of the rare biosphere at a very fine phylogenetic scale, over significant geographic and bathymetric gradients.

  8. Mapping and modelling the geographical distribution of soil-transmitted helminthiases in Peninsular Malaysia: implications for control approaches

    Directory of Open Access Journals (Sweden)

    Romano Ngui

    2014-05-01

    Full Text Available Soil-transmitted helminth (STH infections in Malaysia are still highly prevalent, especially in rural and remote communities. Complete estimations of the total disease burden in the country has not been performed, since available data are not easily accessible in the public domain. The current study utilised geographical information system (GIS to collate and map the distribution of STH infections from available empirical survey data in Peninsular Malaysia, highlighting areas where information is lacking. The assembled database, comprising surveys conducted between 1970 and 2012 in 99 different locations, represents one of the most comprehensive compilations of STH infections in the country. It was found that the geographical distribution of STH varies considerably with no clear pattern across the surveyed locations. Our attempt to generate predictive risk maps of STH infections on the basis of ecological limits such as climate and other environmental factors shows that the prevalence of Ascaris lumbricoides is low along the western coast and the southern part of the country, whilst the prevalence is high in the central plains and in the North. In the present study, we demonstrate that GIS can play an important role in providing data for the implementation of sustainable and effective STH control programmes to policy-makers and authorities in charge.

  9. Soil Survey Geographic (SSURGO) - Kinds and Distribution of Soils

    Data.gov (United States)

    California Natural Resource Agency — This data set is a digital soil survey and generally is the most detailed level of soil geographic data developed by the National Cooperative Soil Survey. The...

  10. Host Ecology Rather Than Host Phylogeny Drives Amphibian Skin Microbial Community Structure in the Biodiversity Hotspot of Madagascar

    Science.gov (United States)

    Bletz, Molly C.; Archer, Holly; Harris, Reid N.; McKenzie, Valerie J.; Rabemananjara, Falitiana C. E.; Rakotoarison, Andolalao; Vences, Miguel

    2017-01-01

    Host-associated microbiotas of vertebrates are diverse and complex communities that contribute to host health. In particular, for amphibians, cutaneous microbial communities likely play a significant role in pathogen defense; however, our ecological understanding of these communities is still in its infancy. Here, we take advantage of the fully endemic and locally species-rich amphibian fauna of Madagascar to investigate the factors structuring amphibian skin microbiota on a large scale. Using amplicon-based sequencing, we evaluate how multiple host species traits and site factors affect host bacterial diversity and community structure. Madagascar is home to over 400 native frog species, all of which are endemic to the island; more than 100 different species are known to occur in sympatry within multiple rainforest sites. We intensively sampled frog skin bacterial communities, from over 800 amphibians from 89 species across 30 sites in Madagascar during three field visits, and found that skin bacterial communities differed strongly from those of the surrounding environment. Richness of bacterial operational taxonomic units (OTUs) and phylogenetic diversity differed among host ecomorphs, with arboreal frogs exhibiting lower richness and diversity than terrestrial and aquatic frogs. Host ecomorphology was the strongest factor influencing microbial community structure, with host phylogeny and site parameters (latitude and elevation) explaining less but significant portions of the observed variation. Correlation analysis and topological congruency analyses revealed little to no phylosymbiosis for amphibian skin microbiota. Despite the observed geographic variation and low phylosymbiosis, we found particular OTUs that were differentially abundant between particular ecomorphs. For example, the genus Pigmentiphaga (Alcaligenaceae) was significantly enriched on arboreal frogs, Methylotenera (Methylophilaceae) was enriched on aquatic frogs, and Agrobacterium (Rhizobiaceae

  11. Host Ecology Rather Than Host Phylogeny Drives Amphibian Skin Microbial Community Structure in the Biodiversity Hotspot of Madagascar

    Directory of Open Access Journals (Sweden)

    Molly C. Bletz

    2017-08-01

    Full Text Available Host-associated microbiotas of vertebrates are diverse and complex communities that contribute to host health. In particular, for amphibians, cutaneous microbial communities likely play a significant role in pathogen defense; however, our ecological understanding of these communities is still in its infancy. Here, we take advantage of the fully endemic and locally species-rich amphibian fauna of Madagascar to investigate the factors structuring amphibian skin microbiota on a large scale. Using amplicon-based sequencing, we evaluate how multiple host species traits and site factors affect host bacterial diversity and community structure. Madagascar is home to over 400 native frog species, all of which are endemic to the island; more than 100 different species are known to occur in sympatry within multiple rainforest sites. We intensively sampled frog skin bacterial communities, from over 800 amphibians from 89 species across 30 sites in Madagascar during three field visits, and found that skin bacterial communities differed strongly from those of the surrounding environment. Richness of bacterial operational taxonomic units (OTUs and phylogenetic diversity differed among host ecomorphs, with arboreal frogs exhibiting lower richness and diversity than terrestrial and aquatic frogs. Host ecomorphology was the strongest factor influencing microbial community structure, with host phylogeny and site parameters (latitude and elevation explaining less but significant portions of the observed variation. Correlation analysis and topological congruency analyses revealed little to no phylosymbiosis for amphibian skin microbiota. Despite the observed geographic variation and low phylosymbiosis, we found particular OTUs that were differentially abundant between particular ecomorphs. For example, the genus Pigmentiphaga (Alcaligenaceae was significantly enriched on arboreal frogs, Methylotenera (Methylophilaceae was enriched on aquatic frogs, and Agrobacterium

  12. Host Ecology Rather Than Host Phylogeny Drives Amphibian Skin Microbial Community Structure in the Biodiversity Hotspot of Madagascar.

    Science.gov (United States)

    Bletz, Molly C; Archer, Holly; Harris, Reid N; McKenzie, Valerie J; Rabemananjara, Falitiana C E; Rakotoarison, Andolalao; Vences, Miguel

    2017-01-01

    Host-associated microbiotas of vertebrates are diverse and complex communities that contribute to host health. In particular, for amphibians, cutaneous microbial communities likely play a significant role in pathogen defense; however, our ecological understanding of these communities is still in its infancy. Here, we take advantage of the fully endemic and locally species-rich amphibian fauna of Madagascar to investigate the factors structuring amphibian skin microbiota on a large scale. Using amplicon-based sequencing, we evaluate how multiple host species traits and site factors affect host bacterial diversity and community structure. Madagascar is home to over 400 native frog species, all of which are endemic to the island; more than 100 different species are known to occur in sympatry within multiple rainforest sites. We intensively sampled frog skin bacterial communities, from over 800 amphibians from 89 species across 30 sites in Madagascar during three field visits, and found that skin bacterial communities differed strongly from those of the surrounding environment. Richness of bacterial operational taxonomic units (OTUs) and phylogenetic diversity differed among host ecomorphs, with arboreal frogs exhibiting lower richness and diversity than terrestrial and aquatic frogs. Host ecomorphology was the strongest factor influencing microbial community structure, with host phylogeny and site parameters (latitude and elevation) explaining less but significant portions of the observed variation. Correlation analysis and topological congruency analyses revealed little to no phylosymbiosis for amphibian skin microbiota. Despite the observed geographic variation and low phylosymbiosis, we found particular OTUs that were differentially abundant between particular ecomorphs. For example, the genus Pigmentiphaga (Alcaligenaceae) was significantly enriched on arboreal frogs, Methylotenera (Methylophilaceae) was enriched on aquatic frogs, and Agrobacterium (Rhizobiaceae

  13. Current Knowledge of Leishmania Vectors in Mexico: How Geographic Distributions of Species Relate to Transmission Areas

    Science.gov (United States)

    González, Camila; Rebollar-Téllez, Eduardo A.; Ibáñez-Bernal, Sergio; Becker-Fauser, Ingeborg; Martínez-Meyer, Enrique; Peterson, A. Townsend; Sánchez-Cordero, Víctor

    2011-01-01

    Leishmaniases are a group of vector-borne diseases with different clinical manifestations caused by parasites transmitted by sand fly vectors. In Mexico, the sand fly Lutzomyia olmeca olmeca is the only vector proven to transmit the parasite Leishmania mexicana to humans, which causes leishmaniasis. Other vector species with potential medical importance have been obtained, but their geographic distributions and relation to transmission areas have never been assessed. We modeled the ecological niches of nine sand fly species and projected niches to estimate potential distributions by using known occurrences, environmental coverages, and the algorithms GARP and Maxent. All vector species were distributed in areas with known recurrent transmission, except for Lu. diabolica, which appeared to be related only to areas of occasional transmission in northern Mexico. The distribution of Lu. o. olmeca does not overlap with all reported cutaneous leishmaniasis cases, suggesting that Lu. cruciata and Lu. shannoni are likely also involved as primary vectors in those areas. Our study provides useful information of potential risk areas of leishmaniasis transmission in Mexico. PMID:22049037

  14. Diversity and host range of foliar fungal endophytes: are tropical leaves biodiversity hotspots?

    Science.gov (United States)

    Arnold, A Elizabeth; Lutzoni, F

    2007-03-01

    Fungal endophytes are found in asymptomatic photosynthetic tissues of all major lineages of land plants. The ubiquity of these cryptic symbionts is clear, but the scale of their diversity, host range, and geographic distributions are unknown. To explore the putative hyperdiversity of tropical leaf endophytes, we compared endophyte communities along a broad latitudinal gradient from the Canadian arctic to the lowland tropical forest of central Panama. Here, we use molecular sequence data from 1403 endophyte strains to show that endophytes increase in incidence, diversity, and host breadth from arctic to tropical sites. Endophyte communities from higher latitudes are characterized by relatively few species from many different classes of Ascomycota, whereas tropical endophyte assemblages are dominated by a small number of classes with a very large number of endophytic species. The most easily cultivated endophytes from tropical plants have wide host ranges, but communities are dominated by a large number of rare species whose host range is unclear. Even when only the most easily cultured species are considered, leaves of tropical trees represent hotspots of fungal species diversity, containing numerous species not yet recovered from other biomes. The challenge remains to recover and identify those elusive and rarely cultured taxa with narrower host ranges, and to elucidate the ecological roles of these little-known symbionts in tropical forests.

  15. Different distribution patterns between putative ercoid mycorrhizal and other fungal assemblages in roots of Rhododendron decorum in the Southwest of China.

    Directory of Open Access Journals (Sweden)

    Lifu Sun

    Full Text Available Fungal diversity within plant roots is affected by several factors such as dispersal limitation, habitat filtering, and plant host preference. Given the differences in life style between symbiotic and non-symbiotic fungi, the main factors affecting these two groups of fungi may be different. We assessed the diversity of root associated fungi of Rhododendron decorum using internal transcribed spacer (ITS sequencing and terminal restriction fragment length polymorphism (T-RFLP analysis, and our aim was to evaluate the role of different factors in structuring ericoid mycorrhizal (ERM and non-ericoid mycorrhizal (NEM fungal communities. Thirty-five fungal operational taxonomic units (OTUs were found in roots of R. decorum, of which 25 were putative ERM fungal species. Of the two main groups of known ERM, helotialean fungi were more abundant and common than sebacinalean species. Geographic and host patterning of the fungal assemblages were different for ERM and NEM. The distribution of putative ERM fungal terminal restriction fragments (TRFs showed that there were more common species within ERM than in the NEM fungal assemblages. Results of Mantel tests indicated that the composition of NEM fungal assemblages correlated with geographic parameters while ERM fungal assemblages lacked a significant geographic pattern and instead were correlated with host genotype. Redundancy analysis (RDA showed that the NEM fungal assemblages were significantly correlated with latitude, longitude, elevation, mean annual precipitation (MAP, and axis 2 of a host-genetic principle component analysis (PCA, while ERM fungal assemblages correlated only with latitude and axis 1 of the host-genetic PCA. We conclude that ERM and NEM assemblages are affected by different factors, with the host genetic composition more important for ERM and geographic factors more important for NEM assemblages. Our results contribute to understanding the roles of dispersal limitation, abiotic

  16. Ecology of Meimuna mongolica (Hemiptera: Cicadidae) Nymphs: Instars, Morphological Variation, Vertical Distribution and Population Density, Host-Plant Selection, and Emergence Phenology

    Science.gov (United States)

    Li, Qinglong; Yang, Mingsheng; Liu, Yunxiang; Wei, Cong

    2015-01-01

    The cicada Meimuna mongolica (Distant) (Hemiptera: Cicadidae) is one of the most important pests of economic forest in Guanzhong Plain of Shaanxi Province, China. Information about ecological characteristics and some sustainable control measures of this species is urgently required for its control. In this study, nymphal instars, morphological variation, vertical distribution, and population density in soil, and emergence phenology of nymphs of M. mongolica on three main host plants (Pinus tabuliformis Carr., Populus tomentosa Carr., and Pyrus xerophila Yü) were studied, based on combined morphological and molecular identification, investigation of the first-instar nymphs hatched from eggs and others excavated from soil, and investigation of exuviae in the adult emergence period. Five nymphal instars of M. mongolica were redetermined according to the distribution plots of the head capsule widths of the nymphs. Nymphs of third and fourth instars showed morphological variation, which is closely related to host-plant association. The mean densities of nymphs in soil under the three host plants were significantly different, indicating a distinct host preference. The nymphs could extend their distribution from the 0–10 cm soil layer to the 51–60 cm soil layer underground but not beyond 60 cm soil layer under all the three host plants. The 21–30 cm soil layer under all the three host plants has the highest nymphal population density. The sex ratio of the entire population was nearly 50:50, but males dominated in the early half of the duration of the emergence. These ecological characteristics of M. mongolica could provide important information for sustainable control measures.

  17. Geographical patterns in cyanobacteria distribution: climate influence at regional scale.

    Science.gov (United States)

    Pitois, Frédéric; Thoraval, Isabelle; Baurès, Estelle; Thomas, Olivier

    2014-01-28

    Cyanobacteria are a component of public health hazards in freshwater environments because of their potential as toxin producers. Eutrophication has long been considered the main cause of cyanobacteria outbreak and proliferation, whereas many studies emphasized the effect of abiotic parameters (mainly temperature and light) on cell growth rate or toxin production. In view of the growing concerns of global change consequences on public health parameters, this study attempts to enlighten climate influence on cyanobacteria at regional scale in Brittany (NW France). The results show that homogeneous cyanobacteria groups are associated with climatic domains related to temperature, global radiation and pluviometry, whereas microcystins (MCs) occurrences are only correlated to local cyanobacteria species composition. As the regional climatic gradient amplitude is similar to the projected climate evolution on a 30-year timespan, a comparison between the present NW and SE situations was used to extrapolate the evolution of geographical cyanobacteria distribution in Brittany. Cyanobacteria composition should shift toward species associated with more frequent Microcystins occurrences along a NW/SE axis whereas lakes situated along a SW/NE axis should transition to species (mainly Nostocales) associated with lower MCs detection frequencies.

  18. Molecular and biometric assessment of Myzodium mimulicola (Drew & Sampson) (Hemiptera, Aphididae), new synonymy, host, and distributional data

    Science.gov (United States)

    Molecular and biometric assessment and subsequent redescription of Myzodium mimulicola (Drew & Sampson) is provided. New host and distributional data for North America are presented, including the first record from Alaska. The current study determined that Myzodium knowltoni (Smith & Robinson) is a ...

  19. Geographic distribution and taxonomic circumscription of populations within Coryphantha section Robustispina (Cactaceae).

    Science.gov (United States)

    Baker, Marc A; Butterworth, Charles A

    2013-05-01

    Taxonomic circumscription of subspecific taxa within Coryphantha robustispina was evaluated with morphological data and microsatellites. This study was the first to compare adequately sampled morphological and DNA analyses at the population level in the Cactaceae. This comparison was important to test reliability of both methods and to gain a better understanding of phytogeography, evolution, and systematics of the species, knowledge that could prove useful for other taxa as well. Populations of C. robustispina subsp. robustispina are listed as endangered by the U. S. Fish and Wildlife Service. Our primary goal was to explore correlations among geographical distribution, morphology, and genetics of selected populations throughout the range of the species and the outgroup, C. poselgeriana. • Stem characters were measured for 638 individuals among 16 populations. Flower characters were measured for 180 individuals among 12 populations. Ten microsatellite DNA loci were isolated and characterized for 204 individuals among 13 populations. Data were analyzed using various multivariate analyses. • Our results indicated that, within Coryphantha robustispina, there were three morphologically, genetically, and geographically coherent groups represented by the names C. robustispina subsp. robustispina, C. robustispina subsp. uncinata, and C. robustispina subsp. scheeri. For most analyses, distinctions among the three groups were primarily not as great as those between any one of them and the outgroup. • Results suggested that the three subspecific taxa within Coryphantha robustispina are good subspecies but should not be elevated to species rank. The closely aligned results between morphology and microsatellite data support the design and utility of both methods.

  20. Maximizing hosting capacity of renewable energy sources in distribution networks: A multi-objective and scenario-based approach

    International Nuclear Information System (INIS)

    Rabiee, Abbas; Mohseni-Bonab, Seyed Masoud

    2017-01-01

    Due to the development of renewable energy sources (RESs), maximization of hosting capacity (HC) of RESs has gained significant interest in the existing and future power systems. HC maximization should be performed considering various technical constraints like power flow equations, limits on the distribution feeders' voltages and currents, as well as economic constraints such as the cost of energy procurement from the upstream network and power generation by RESs. RESs are volatile and uncertain in nature. Thus, it is necessary to handle their inherent uncertainties in the HC maximization problem. Wind power is now the fastest growing RESs around the world. Hence, in this paper a stochastic multi-objective optimization model is proposed to maximize the distribution network's HC for wind power and minimize the energy procurement costs in a wind integrated power system. The following objective functions are considered: 1) Cost of the purchased energy from upstream network (to be minimized) and 2) Operation and maintenance cost of wind farms. The proposed model is examined on a standard radial 69 bus distribution feeder and a practical 152 bus distribution system. The numerical results substantiate that the proposed model is an effective tool for distribution network operators (DNOs) to consider both technical and economic aspects of distribution network's HC for RESs. - Highlights: • Hosting capacity of wind power is improved in distribution feeders. • A stochastic multi-objective optimization model is proposed. • Wind power and load uncertainties are modeled by scenario based approach. • Purchased energy cost from upstream network and O&M cost of wind farms are used.

  1. Studies of archaeal virus-host systems in thermal environments

    DEFF Research Database (Denmark)

    Erdmann, Susanne

    Since the first organisms were isolated from hot springs, a large number of viruses were found in these geothermal active environments, most of them infecting Archaea. Archaeal viruses form a separate lineage from those of Eukarya and Bacteria often showing exceptional morphologies and genomic...... features. Most of the isolated archaeal viruses infecting members of the Crenarchaeota have been characterized regarding their genome, the structure of their virions and their influence on the host viability. Only a few, SIRV a rod-shaped and STIV an icosahedrical virus, have been subjected to more...... extensive studies. This work investigates tailed spindle-shaped viruses that we have isolated from different geographical acidothermal, terrestrial hot springs and they primarily infect members of the genus Sulfolobales. The wide distribution of these viruses was established and, moreover, genomic...

  2. Geographic Analysis of the Radiation Oncology Workforce

    Energy Technology Data Exchange (ETDEWEB)

    Aneja, Sanjay [Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT (United States); Cancer Outcomes, Policy, and Effectiveness Research Center at Yale, New Haven, CT (United States); Smith, Benjamin D. [University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Gross, Cary P. [Cancer Outcomes, Policy, and Effectiveness Research Center at Yale, New Haven, CT (United States); Department of General Internal Medicine, Yale University School of Medicine, New Haven, CT (United States); Wilson, Lynn D. [Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT (United States); Haffty, Bruce G. [Cancer Institute of New Jersey, New Brunswick, NJ (United States); Roberts, Kenneth [Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT (United States); Yu, James B., E-mail: james.b.yu@yale.edu [Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT (United States); Cancer Outcomes, Policy, and Effectiveness Research Center at Yale, New Haven, CT (United States)

    2012-04-01

    Purpose: To evaluate trends in the geographic distribution of the radiation oncology (RO) workforce. Methods and Materials: We used the 1995 and 2007 versions of the Area Resource File to map the ratio of RO to the population aged 65 years or older (ROR) within different health service areas (HSA) within the United States. We used regression analysis to find associations between population variables and 2007 ROR. We calculated Gini coefficients for ROR to assess the evenness of RO distribution and compared that with primary care physicians and total physicians. Results: There was a 24% increase in the RO workforce from 1995 to 2007. The overall growth in the RO workforce was less than that of primary care or the overall physician workforce. The mean ROR among HSAs increased by more than one radiation oncologist per 100,000 people aged 65 years or older, from 5.08 per 100,000 to 6.16 per 100,000. However, there remained consistent geographic variability concerning RO distribution, specifically affecting the non-metropolitan HSAs. Regression analysis found higher ROR in HSAs that possessed higher education (p = 0.001), higher income (p < 0.001), lower unemployment rates (p < 0.001), and higher minority population (p = 0.022). Gini coefficients showed RO distribution less even than for both primary care physicians and total physicians (0.326 compared with 0.196 and 0.292, respectively). Conclusions: Despite a modest growth in the RO workforce, there exists persistent geographic maldistribution of radiation oncologists allocated along socioeconomic and racial lines. To solve problems surrounding the RO workforce, issues concerning both gross numbers and geographic distribution must be addressed.

  3. Geographic Analysis of the Radiation Oncology Workforce

    International Nuclear Information System (INIS)

    Aneja, Sanjay; Smith, Benjamin D.; Gross, Cary P.; Wilson, Lynn D.; Haffty, Bruce G.; Roberts, Kenneth; Yu, James B.

    2012-01-01

    Purpose: To evaluate trends in the geographic distribution of the radiation oncology (RO) workforce. Methods and Materials: We used the 1995 and 2007 versions of the Area Resource File to map the ratio of RO to the population aged 65 years or older (ROR) within different health service areas (HSA) within the United States. We used regression analysis to find associations between population variables and 2007 ROR. We calculated Gini coefficients for ROR to assess the evenness of RO distribution and compared that with primary care physicians and total physicians. Results: There was a 24% increase in the RO workforce from 1995 to 2007. The overall growth in the RO workforce was less than that of primary care or the overall physician workforce. The mean ROR among HSAs increased by more than one radiation oncologist per 100,000 people aged 65 years or older, from 5.08 per 100,000 to 6.16 per 100,000. However, there remained consistent geographic variability concerning RO distribution, specifically affecting the non-metropolitan HSAs. Regression analysis found higher ROR in HSAs that possessed higher education (p = 0.001), higher income (p < 0.001), lower unemployment rates (p < 0.001), and higher minority population (p = 0.022). Gini coefficients showed RO distribution less even than for both primary care physicians and total physicians (0.326 compared with 0.196 and 0.292, respectively). Conclusions: Despite a modest growth in the RO workforce, there exists persistent geographic maldistribution of radiation oncologists allocated along socioeconomic and racial lines. To solve problems surrounding the RO workforce, issues concerning both gross numbers and geographic distribution must be addressed.

  4. The Geographic Information Grid System Based on Mobile Agent

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    We analyze the deficiencies of current application systems, and discuss the key requirements of distributed Geographic Information service (GIS). We construct the distributed GIS on grid platform. Considering the flexibility and efficiency, we integrate the mobile agent technology into the system. We propose a new prototype system, the Geographic Information Grid System (GIGS) based on mobile agent. This system has flexible services and high performance, and improves the sharing of distributed resources. The service strategy of the system and the examples are also presented.

  5. Molecular and biometric assessment of Myzodium mimulicola (Hemiptera: Aphididae), with new synonymy and host and distributional data

    Science.gov (United States)

    Molecular and biometric assessment and redescription of Myzodium mimulicola (Drew & Sampson) are provided. New host and distributional data for North America are presented, including the first record from Alaska. Myzodium knowltoni (Smith & Robinson) is found to be a junior subjective synonym of M....

  6. Geographic Distribution of Leishmania Species in Ecuador Based on the Cytochrome B Gene Sequence Analysis.

    Science.gov (United States)

    Kato, Hirotomo; Gomez, Eduardo A; Martini-Robles, Luiggi; Muzzio, Jenny; Velez, Lenin; Calvopiña, Manuel; Romero-Alvarez, Daniel; Mimori, Tatsuyuki; Uezato, Hiroshi; Hashiguchi, Yoshihisa

    2016-07-01

    A countrywide epidemiological study was performed to elucidate the current geographic distribution of causative species of cutaneous leishmaniasis (CL) in Ecuador by using FTA card-spotted samples and smear slides as DNA sources. Putative Leishmania in 165 samples collected from patients with CL in 16 provinces of Ecuador were examined at the species level based on the cytochrome b gene sequence analysis. Of these, 125 samples were successfully identified as Leishmania (Viannia) guyanensis, L. (V.) braziliensis, L. (V.) naiffi, L. (V.) lainsoni, and L. (Leishmania) mexicana. Two dominant species, L. (V.) guyanensis and L. (V.) braziliensis, were widely distributed in Pacific coast subtropical and Amazonian tropical areas, respectively. Recently reported L. (V.) naiffi and L. (V.) lainsoni were identified in Amazonian areas, and L. (L.) mexicana was identified in an Andean highland area. Importantly, the present study demonstrated that cases of L. (V.) braziliensis infection are increasing in Pacific coast areas.

  7. New host, geographical records, and factors affecting the prevalence of helminths infection from synanthropic rodents in Yucatán, Mexico

    OpenAIRE

    Panti-May J. A.; Palomo-Arjona E.; Gurubel-González Y.; Torres-Castro M. A.; Vidal-Martínez V. M.; Machain-Williams C.; Hernández-Betancourt S. F.; Del Rosario Robles M.

    2017-01-01

    The aim of this paper was to study the occurrence of helminths in Mus musculus and Rattus rattus from urban, suburban and rural settlements in Yucatán, Mexico; and to analyse the host factors (e.g. sex) related to helminths’ distribution. Helminths in a total of 279 rodents were surveyed by visual examination of the liver for metacestodes and faecal examination for helminth eggs using the formalin-ethyl acetate sedimentation technique. The cestodes Hydatigera taeniaeformis (metacestodes detec...

  8. Effects of Abiotic Factors on the Geographic Distribution of Body Size Variation and Chromosomal Polymorphisms in Two Neotropical Grasshopper Species (Dichroplus: Melanoplinae: Acrididae

    Directory of Open Access Journals (Sweden)

    Claudio J. Bidau

    2012-01-01

    Full Text Available We review the effects of abiotic factors on body size in two grasshopper species with large geographical distributions: Dichroplus pratensis and D. vittatus, inhabiting Argentina in diverse natural habitats. Geographical spans for both species provide an opportunity to study the effects of changes in abiotic factors on body size. The analyses of body size distribution in both species revealed a converse Bergmannian pattern: body size is positively correlated with latitude, altitude, and seasonality that influences time available for development and growth. Allen’s rule is also inverted. Morphological variability increases towards the ends of the Bergmannian clines and, in D. pratensis, is related with a central-marginal distribution of chromosomal variants that influence recombination. The converse Bergmannian patterns influence sexual size dimorphism in both species but in different fashions. Body size variation at a microspatial scale in D. pratensis is extremely sensitive to microclimatic clines. We finally compare our results with those for other Orthopteran species.

  9. [Prediction of potential geographic distribution of Lyme disease in Qinghai province with Maximum Entropy model].

    Science.gov (United States)

    Zhang, Lin; Hou, Xuexia; Liu, Huixin; Liu, Wei; Wan, Kanglin; Hao, Qin

    2016-01-01

    To predict the potential geographic distribution of Lyme disease in Qinghai by using Maximum Entropy model (MaxEnt). The sero-diagnosis data of Lyme disease in 6 counties (Huzhu, Zeku, Tongde, Datong, Qilian and Xunhua) and the environmental and anthropogenic data including altitude, human footprint, normalized difference vegetation index (NDVI) and temperature in Qinghai province since 1990 were collected. By using the data of Huzhu Zeku and Tongde, the prediction of potential distribution of Lyme disease in Qinghai was conducted with MaxEnt. The prediction results were compared with the human sero-prevalence of Lyme disease in Datong, Qilian and Xunhua counties in Qinghai. Three hot spots of Lyme disease were predicted in Qinghai, which were all in the east forest areas. Furthermore, the NDVI showed the most important role in the model prediction, followed by human footprint. Datong, Qilian and Xunhua counties were all in eastern Qinghai. Xunhua was in hot spot areaⅡ, Datong was close to the north of hot spot area Ⅲ, while Qilian with lowest sero-prevalence of Lyme disease was not in the hot spot areas. The data were well modeled in MaxEnt (Area Under Curve=0.980). The actual distribution of Lyme disease in Qinghai was in consistent with the results of the model prediction. MaxEnt could be used in predicting the potential distribution patterns of Lyme disease. The distribution of vegetation and the range and intensity of human activity might be related with Lyme disease distribution.

  10. Mapping and Modelling the Geographical Distribution and Environmental Limits of Podoconiosis in Ethiopia.

    Science.gov (United States)

    Deribe, Kebede; Cano, Jorge; Newport, Melanie J; Golding, Nick; Pullan, Rachel L; Sime, Heven; Gebretsadik, Abeba; Assefa, Ashenafi; Kebede, Amha; Hailu, Asrat; Rebollo, Maria P; Shafi, Oumer; Bockarie, Moses J; Aseffa, Abraham; Hay, Simon I; Reithinger, Richard; Enquselassie, Fikre; Davey, Gail; Brooker, Simon J

    2015-01-01

    Ethiopia is assumed to have the highest burden of podoconiosis globally, but the geographical distribution and environmental limits and correlates are yet to be fully investigated. In this paper we use data from a nationwide survey to address these issues. Our analyses are based on data arising from the integrated mapping of podoconiosis and lymphatic filariasis (LF) conducted in 2013, supplemented by data from an earlier mapping of LF in western Ethiopia in 2008-2010. The integrated mapping used woreda (district) health offices' reports of podoconiosis and LF to guide selection of survey sites. A suite of environmental and climatic data and boosted regression tree (BRT) modelling was used to investigate environmental limits and predict the probability of podoconiosis occurrence. Data were available for 141,238 individuals from 1,442 communities in 775 districts from all nine regional states and two city administrations of Ethiopia. In 41.9% of surveyed districts no cases of podoconiosis were identified, with all districts in Affar, Dire Dawa, Somali and Gambella regional states lacking the disease. The disease was most common, with lymphoedema positivity rate exceeding 5%, in the central highlands of Ethiopia, in Amhara, Oromia and Southern Nations, Nationalities and Peoples regional states. BRT modelling indicated that the probability of podoconiosis occurrence increased with increasing altitude, precipitation and silt fraction of soil and decreased with population density and clay content. Based on the BRT model, we estimate that in 2010, 34.9 (95% confidence interval [CI]: 20.2-51.7) million people (i.e. 43.8%; 95% CI: 25.3-64.8% of Ethiopia's national population) lived in areas environmentally suitable for the occurrence of podoconiosis. Podoconiosis is more widespread in Ethiopia than previously estimated, but occurs in distinct geographical regions that are tied to identifiable environmental factors. The resultant maps can be used to guide programme planning

  11. Mapping and Modelling the Geographical Distribution and Environmental Limits of Podoconiosis in Ethiopia.

    Directory of Open Access Journals (Sweden)

    Kebede Deribe

    Full Text Available Ethiopia is assumed to have the highest burden of podoconiosis globally, but the geographical distribution and environmental limits and correlates are yet to be fully investigated. In this paper we use data from a nationwide survey to address these issues.Our analyses are based on data arising from the integrated mapping of podoconiosis and lymphatic filariasis (LF conducted in 2013, supplemented by data from an earlier mapping of LF in western Ethiopia in 2008-2010. The integrated mapping used woreda (district health offices' reports of podoconiosis and LF to guide selection of survey sites. A suite of environmental and climatic data and boosted regression tree (BRT modelling was used to investigate environmental limits and predict the probability of podoconiosis occurrence.Data were available for 141,238 individuals from 1,442 communities in 775 districts from all nine regional states and two city administrations of Ethiopia. In 41.9% of surveyed districts no cases of podoconiosis were identified, with all districts in Affar, Dire Dawa, Somali and Gambella regional states lacking the disease. The disease was most common, with lymphoedema positivity rate exceeding 5%, in the central highlands of Ethiopia, in Amhara, Oromia and Southern Nations, Nationalities and Peoples regional states. BRT modelling indicated that the probability of podoconiosis occurrence increased with increasing altitude, precipitation and silt fraction of soil and decreased with population density and clay content. Based on the BRT model, we estimate that in 2010, 34.9 (95% confidence interval [CI]: 20.2-51.7 million people (i.e. 43.8%; 95% CI: 25.3-64.8% of Ethiopia's national population lived in areas environmentally suitable for the occurrence of podoconiosis.Podoconiosis is more widespread in Ethiopia than previously estimated, but occurs in distinct geographical regions that are tied to identifiable environmental factors. The resultant maps can be used to guide

  12. Description of the male of Eburella pinima Martins and notes on the geographical distribution of Eburodacrys aenigma Galileo & Martins and Eburodacrys lanei Zajciw (Coleoptera, Cerambycidae

    Directory of Open Access Journals (Sweden)

    Juan Pablo Botero

    2013-12-01

    Full Text Available Description of the male of Eburella pinima Martins and notes on the geographical distribution of Eburodacrys aenigma Galileo & Martins and Eburodacrys lanei Zajciw (Coleoptera, Cerambycidae. The male of Eburella pinima Martins, 1997 is described and illustrated for the first time. Information on Eburodacrys aenigma Galileo & Martins, 2006, previously known only from the female holotype, which lacked locality label, is herein complemented. This species is recorded from Brazil and the male is depicted for the first time. The geographical distribution of Eburodacrys lanei Zajciw, 1958 is further restricted here as some previous records are confirmed to result from misidentifications of E. aenigma.

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

    Science.gov (United States)

    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.

  14. Continental-scale variation in seaweed host-associated bacterial communities is a function of host condition, not geography.

    Science.gov (United States)

    Marzinelli, Ezequiel M; Campbell, Alexandra H; Zozaya Valdes, Enrique; Vergés, Adriana; Nielsen, Shaun; Wernberg, Thomas; de Bettignies, Thibaut; Bennett, Scott; Caporaso, J Gregory; Thomas, Torsten; Steinberg, Peter D

    2015-10-01

    Interactions between hosts and associated microbial communities can fundamentally shape the development and ecology of 'holobionts', from humans to marine habitat-forming organisms such as seaweeds. In marine systems, planktonic microbial community structure is mainly driven by geography and related environmental factors, but the large-scale drivers of host-associated microbial communities are largely unknown. Using 16S-rRNA gene sequencing, we characterized 260 seaweed-associated bacterial and archaeal communities on the kelp Ecklonia radiata from three biogeographical provinces spanning 10° of latitude and 35° of longitude across the Australian continent. These phylogenetically and taxonomically diverse communities were more strongly and consistently associated with host condition than geographical location or environmental variables, and a 'core' microbial community characteristic of healthy kelps appears to be lost when hosts become stressed. Microbial communities on stressed individuals were more similar to each other among locations than those on healthy hosts. In contrast to biogeographical patterns of planktonic marine microbial communities, host traits emerge as critical determinants of associated microbial community structure of these holobionts, even at a continental scale. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. Geographic Analysis of Neurosurgery Workforce in Korea

    Science.gov (United States)

    Park, Hye Ran; Park, Sukh Que; Kim, Jae Hyun; Hwang, Jae Chan; Lee, Gwang Soo; Chang, Jae-Chil

    2018-01-01

    Objective In respect of the health and safety of the public, universal access to health care is an issue of the greatest importance. The geographic distribution of doctors is one of the important factors contributing to access to health care. The aim of this study is to assess the imbalances in the geographic distribution of neurosurgeons across Korea. Methods Population data was obtained from the National Statistical Office. We classified geographic groups into 7 metropolitan cities, 78 non-metropolitan cities, and 77 rural areas. The number of doctors and neurosurgeons per 100000 populations in each county unit was calculated using the total number of doctors and neurosurgeons at the country level from 2009 to 2015. The density levels of neurosurgeon and doctor were calculated and depicted in maps. Results Between 2009 and 2015, the number of neurosurgeons increased from 2002 to 2557, and the ratio of neurosurgeons per 100000 populations increased from 4.02 to 4.96. The number of neurosurgeons per 100000 populations was highest in metropolitan cities and lowest in rural areas from 2009 to 2015. A comparison of the geographic distribution of neurosurgeons in 2009 and 2015 showed an increase in the regional gap. The neurosurgeon density was affected by country unit characteristics (p=0.000). Conclusion Distribution of neurosurgeons throughout Korea is uneven. Neurosurgeons are being increasingly concentrated in a limited number of metropolitan cities. This phenomenon will need to be accounted when planning for a supply of neurosurgeons, allocation of resources and manpower, and the provision of regional neurosurgical services. PMID:29354242

  16. Geographic Analysis of Neurosurgery Workforce in Korea.

    Science.gov (United States)

    Park, Hye Ran; Park, Sukh Que; Kim, Jae Hyun; Hwang, Jae Chan; Lee, Gwang Soo; Chang, Jae-Chil

    2018-01-01

    In respect of the health and safety of the public, universal access to health care is an issue of the greatest importance. The geographic distribution of doctors is one of the important factors contributing to access to health care. The aim of this study is to assess the imbalances in the geographic distribution of neurosurgeons across Korea. Population data was obtained from the National Statistical Office. We classified geographic groups into 7 metropolitan cities, 78 non-metropolitan cities, and 77 rural areas. The number of doctors and neurosurgeons per 100000 populations in each county unit was calculated using the total number of doctors and neurosurgeons at the country level from 2009 to 2015. The density levels of neurosurgeon and doctor were calculated and depicted in maps. Between 2009 and 2015, the number of neurosurgeons increased from 2002 to 2557, and the ratio of neurosurgeons per 100000 populations increased from 4.02 to 4.96. The number of neurosurgeons per 100000 populations was highest in metropolitan cities and lowest in rural areas from 2009 to 2015. A comparison of the geographic distribution of neurosurgeons in 2009 and 2015 showed an increase in the regional gap. The neurosurgeon density was affected by country unit characteristics ( p =0.000). Distribution of neurosurgeons throughout Korea is uneven. Neurosurgeons are being increasingly concentrated in a limited number of metropolitan cities. This phenomenon will need to be accounted when planning for a supply of neurosurgeons, allocation of resources and manpower, and the provision of regional neurosurgical services.

  17. Host plant adaptation in Drosophila mettleri populations.

    Directory of Open Access Journals (Sweden)

    Sergio Castrezana

    Full Text Available The process of local adaptation creates diversity among allopatric populations, and may eventually lead to speciation. Plant-feeding insect populations that specialize on different host species provide an excellent opportunity to evaluate the causes of ecological specialization and the subsequent consequences for diversity. In this study, we used geographically separated Drosophila mettleri populations that specialize on different host cacti to examine oviposition preference for and larval performance on an array of natural and non-natural hosts (eight total. We found evidence of local adaptation in performance on saguaro cactus (Carnegiea gigantea for populations that are typically associated with this host, and to chemically divergent prickly pear species (Opuntia spp. in a genetically isolated population on Santa Catalina Island. Moreover, each population exhibited reduced performance on the alternative host. This finding is consistent with trade-offs associated with adaptation to these chemically divergent hosts, although we also discuss alternative explanations for this pattern. For oviposition preference, Santa Catalina Island flies were more likely to oviposit on some prickly pear species, but all populations readily laid eggs on saguaro. Experiments with non-natural hosts suggest that factors such as ecological opportunity may play a more important role than host plant chemistry in explaining the lack of natural associations with some hosts.

  18. The Geographical Distribution of Leadership in Globalized Clinical Trials

    NARCIS (Netherlands)

    Hoekman, J.; Frenken, K.; de Zeeuw, D.; Lambers-Heerspink, H.J.

    2012-01-01

    Background: Pharmaceutical trials are mainly initiated by sponsors and investigators in the United States, Western Europe and Japan. However, more and more patients are enrolled in Central and Eastern Europe, Latin America and Asia. The involvement of patients in new geographical settings raises

  19. A Geographic Method for High Resolution Spatial Heat Planning

    DEFF Research Database (Denmark)

    Nielsen, Steffen

    2014-01-01

    more detailed modelling that takes the geographic placement of buildings and the differences among DH systems into account. In the present article, a method for assessing the costs of DH expansions has been developed. The method was applied in a geographic information system (GIS) model that consists...... are considering distribution costs based on the geographic properties of each area and assessing transmission costs based on an iterative process that examines expansion potentials gradually. The GIS model is only applicable to a Danish context, but the method itself can be applied to other countries....... of three parts and assesses the costs of heat production, distribution, and transmission. The model was also applied to an actual case in order to show how it can be used. The model shows many improvements in the method for the assessment of distribution costs and transmission costs. Most notable...

  20. A Geographical Information System Based Approach for Integrated Strategies of Tick Surveillance and Control in the Peri-Urban Natural Reserve of Monte Pellegrino (Palermo, Southern Italy)

    OpenAIRE

    Alessandra Torina; Valeria Blanda; Marcellocalogero Blanda; Michelangelo Auteri; Francesco La Russa; Salvatore Scimeca; Rosalia D’Agostino; Rosaria Disclafani; Sara Villari; Vittoria Currò; Santo Caracappa

    2018-01-01

    Ticks (Acari: Ixodidae) are bloodsucking arthropods involved in pathogen transmission in animals and humans. Tick activity depends on various ecological factors such as vegetation, hosts, and temperature. The aim of this study was to analyse the spatial/temporal distribution of ticks in six sites within a peri-urban area of Palermo (Natural Reserve of Monte Pellegrino) and correlate it with field data using Geographical Information System (GIS) data. A total of 3092 ticks were gathered via dr...

  1. Determinants of the geographical distribution of endemic giardiasis in Ontario, Canada: a spatial modelling approach.

    Science.gov (United States)

    Odoi, A; Martin, S W; Michel, P; Holt, J; Middleton, D; Wilson, J

    2004-10-01

    Giardiasis surveillance data as well as drinking water, socioeconomic and land-use data were used in spatial regression models to investigate determinants of the geographic distribution of endemic giardiasis in southern Ontario. Higher giardiasis rates were observed in areas using surface water [rate ratio (RR) 2.36, 95 % CI 1.38-4.05] and in rural areas (RR 1.79, 95 % CI 1.32-2.37). Lower rates were observed in areas using filtered water (RR 0.55, 95 % CI 0.42-0.94) and in those with high median income (RR 0.62, 95 % CI 0.42-0.92). Chlorination of drinking water, cattle density and intensity of manure application on farmland were not significant determinants. The study shows that waterborne transmission plays an important role in giardiasis distribution in southern Ontario and that well-collected routine surveillance data could be useful for investigation of disease determinants and identification of high-risk communities. This information is useful in guiding decisions on control strategies.

  2. Geographic Distribution of Leishmania Species in Ecuador Based on the Cytochrome B Gene Sequence Analysis

    Science.gov (United States)

    Kato, Hirotomo; Gomez, Eduardo A.; Martini-Robles, Luiggi; Muzzio, Jenny; Velez, Lenin; Calvopiña, Manuel; Romero-Alvarez, Daniel; Mimori, Tatsuyuki; Uezato, Hiroshi; Hashiguchi, Yoshihisa

    2016-01-01

    A countrywide epidemiological study was performed to elucidate the current geographic distribution of causative species of cutaneous leishmaniasis (CL) in Ecuador by using FTA card-spotted samples and smear slides as DNA sources. Putative Leishmania in 165 samples collected from patients with CL in 16 provinces of Ecuador were examined at the species level based on the cytochrome b gene sequence analysis. Of these, 125 samples were successfully identified as Leishmania (Viannia) guyanensis, L. (V.) braziliensis, L. (V.) naiffi, L. (V.) lainsoni, and L. (Leishmania) mexicana. Two dominant species, L. (V.) guyanensis and L. (V.) braziliensis, were widely distributed in Pacific coast subtropical and Amazonian tropical areas, respectively. Recently reported L. (V.) naiffi and L. (V.) lainsoni were identified in Amazonian areas, and L. (L.) mexicana was identified in an Andean highland area. Importantly, the present study demonstrated that cases of L. (V.) braziliensis infection are increasing in Pacific coast areas. PMID:27410039

  3. Geographic Distribution of Leishmania Species in Ecuador Based on the Cytochrome B Gene Sequence Analysis.

    Directory of Open Access Journals (Sweden)

    Hirotomo Kato

    2016-07-01

    Full Text Available A countrywide epidemiological study was performed to elucidate the current geographic distribution of causative species of cutaneous leishmaniasis (CL in Ecuador by using FTA card-spotted samples and smear slides as DNA sources. Putative Leishmania in 165 samples collected from patients with CL in 16 provinces of Ecuador were examined at the species level based on the cytochrome b gene sequence analysis. Of these, 125 samples were successfully identified as Leishmania (Viannia guyanensis, L. (V. braziliensis, L. (V. naiffi, L. (V. lainsoni, and L. (Leishmania mexicana. Two dominant species, L. (V. guyanensis and L. (V. braziliensis, were widely distributed in Pacific coast subtropical and Amazonian tropical areas, respectively. Recently reported L. (V. naiffi and L. (V. lainsoni were identified in Amazonian areas, and L. (L. mexicana was identified in an Andean highland area. Importantly, the present study demonstrated that cases of L. (V. braziliensis infection are increasing in Pacific coast areas.

  4. Differential distribution of lipids in epidermis, gastrodermis and hosted Symbiodinium in the sea anemone Anemonia viridis.

    Science.gov (United States)

    Revel, Johana; Massi, Lionel; Mehiri, Mohamed; Boutoute, Marc; Mayzaud, Patrick; Capron, Laure; Sabourault, Cécile

    2016-01-01

    Cnidarian-dinoflagellate symbiosis mainly relies on nutrient recycling, thus providing both partners with a competitive advantage in nutrient-poor waters. Essential processes related to lipid metabolism can be influenced by various factors, including hyperthermal stress. This can affect the lipid content and distribution in both partners, while contributing to symbiosis disruption and bleaching. In order to gain further insight into the role and distribution of lipids in the cnidarian metabolism, we investigated the lipid composition of the sea anemone Anemonia viridis and its photosynthetic dinoflagellate endosymbionts (Symbiodinium). We compared the lipid content and fatty acid profiles of the host cellular layers, non-symbiotic epidermal and symbiont-containing gastrodermal cells, and those of Symbiodinium, in a mass spectrometry-based assessment. Lipids were more concentrated in Symbiodinium cells, and the lipid class distribution was dominated by polar lipids in all tissues. The fatty acid distribution between host cell layers and Symbiodinium cells suggested potential lipid transfers between the partners. The lipid composition and distribution was modified during short-term hyperthermal stress, mainly in Symbiodinium cells and gastrodermis. Exposure to elevated temperature rapidly caused a decrease in polar lipid C18 unsaturated fatty acids and a strong and rapid decrease in the abundance of polar lipid fatty acids relative to sterols. These lipid indicators could therefore be used as sensitive biomarkers to assess the physiology of symbiotic cnidarians, especially the effect of thermal stress at the onset of cnidarian bleaching. Overall, the findings of this study provide some insight on key lipids that may regulate maintenance of the symbiotic interaction. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Global patterns of Leptospira prevalence in vertebrate reservoir hosts

    DEFF Research Database (Denmark)

    Andersen-Ranberg, Emilie U.; Pipper, Christian Bressen; Jensen, Per Moestrup

    2016-01-01

    leptospirosis requires more detailed information on animal reservoirs that are the source of human infection. We evaluated the prevalence of Leptospira in vertebrates worldwide and its association with taxonomy, geographic region, host biology, ambient temperature, and precipitation patterns. A multivariate...

  6. Ring distributions leading to species formation: a global topographic analysis of geographic barriers associated with ring species.

    Science.gov (United States)

    Monahan, William B; Pereira, Ricardo J; Wake, David B

    2012-03-12

    In the mid 20th century, Ernst Mayr and Theodosius Dobzhansky championed the significance of circular overlaps or ring species as the perfect demonstration of speciation, yet in the over 50 years since, only a handful of such taxa are known. We developed a topographic model to evaluate whether the geographic barriers that favor processes leading to ring species are common or rare, and to predict where other candidate ring barriers might be found. Of the 952,147 geographic barriers identified on the planet, only about 1% are topographically similar to barriers associated with known ring taxa, with most of the likely candidates occurring in under-studied parts of the world (for example, marine environments, tropical latitudes). Predicted barriers separate into two distinct categories: (i) single cohesive barriers (barriers - formed by groups of barriers (each 184,000 to 1.7 million km2) in close geographic proximity (totaling 1.9 to 2.3 million km2) - associated with taxa that differentiate at larger spatial scales (birds: Phylloscopus trochiloides and Larus (sp. argentatus and fuscus)). When evaluated globally, we find a large number of cohesive barriers that are topographically similar to those associated with known ring taxa. Yet, compared to cohesive barriers, an order of magnitude fewer composite barriers are similar to those that favor ring divergence in species with higher dispersal. While these findings confirm that the topographic conditions that favor evolutionary processes leading to ring speciation are, in fact, rare, they also suggest that many understudied natural systems could provide valuable demonstrations of continuous divergence towards the formation of new species. Distinct advantages of the model are that it (i) requires no a priori information on the relative importance of features that define barriers, (ii) can be replicated using any kind of continuously distributed environmental variable, and (iii) generates spatially explicit hypotheses of

  7. Molecular Identification of Paramecium bursaria Syngens and Studies on Geographic Distribution using Mitochondrial Cytochrome C Oxidase Subunit I (COI).

    Science.gov (United States)

    Zagata, Patrycja; Greczek-Stachura, Magdalena; Tarcz, Sebastian; Rautian, Maria

    2015-01-01

    Paramecium bursaria is composed of five syngens that are morphologically indistinguishable but sexually isolated. The aim of the present study was to confirm by molecular methods (analyses of mitochondrial COI) the identification of P. bursaria syngens originating from different geographical locations. Phylograms constructed using both the neighbor-joining and maximum-likelihood methods based on a comparison of 34 sequences of P. bursaria strains and P. multimicronucleatum, P. caudatum and P.calkinsi strains used as outgroups revealed five clusters which correspond to results obtained previously by mating reaction. Our analysis shows the existence of 24 haplotypes for the COI gene sequence in the studied strains. The interspecies haplotype diversity was Hd = 0.967. We confirmed genetic differentiation between strains of P. bursaria and the occurrence of a correlation between geographical distribution and the correspondent syngen.

  8. The geographical co-distribution and socio-ecological drivers of childhood pneumonia and diarrhoea in Queensland, Australia.

    Science.gov (United States)

    Xu, Z; Hu, W; Tong, S

    2015-04-01

    SUMMARY This study aimed to explore the spatio-temporal patterns, geographical co-distribution, and socio-ecological drivers of childhood pneumonia and diarrhoea in Queensland. A Bayesian conditional autoregressive model was used to quantify the impacts of socio-ecological factors on both childhood pneumonia and diarrhoea at a postal area level. A distinct seasonality of childhood pneumonia and diarrhoea was found. Childhood pneumonia and diarrhoea were mainly distributed in the northwest of Queensland. Mount Isa city was the high-risk cluster where childhood pneumonia and diarrhoea co-distributed. Emergency department visits (EDVs) for pneumonia increased by 3% per 10-mm increase in monthly average rainfall in wet seasons. By comparison, a 10-mm increase in monthly average rainfall may cause an increase of 4% in EDVs for diarrhoea. Monthly average temperature was negatively associated with EDVs for childhood diarrhoea in wet seasons. Low socioeconomic index for areas (SEIFA) was associated with high EDVs for childhood pneumonia. Future pneumonia and diarrhoea prevention and control measures in Queensland should focus more on Mount Isa.

  9. Genetic Diversity of Toxoplasma gondii Strains from Different Hosts and Geographical Regions by Sequence Analysis of GRA20 Gene.

    Science.gov (United States)

    Ning, Hong-Rui; Huang, Si-Yang; Wang, Jin-Lei; Xu, Qian-Ming; Zhu, Xing-Quan

    2015-06-01

    Toxoplasma gondii is a eukaryotic parasite of the phylum Apicomplexa, which infects all warm-blood animals, including humans. In the present study, we examined sequence variation in dense granule 20 (GRA20) genes among T. gondii isolates collected from different hosts and geographical regions worldwide. The complete GRA20 genes were amplified from 16 T. gondii isolates using PCR, sequence were analyzed, and phylogenetic reconstruction was analyzed by maximum parsimony (MP) and maximum likelihood (ML) methods. The results showed that the complete GRA20 gene sequence was 1,586 bp in length among all the isolates used in this study, and the sequence variations in nucleotides were 0-7.9% among all strains. However, removing the type III strains (CTG, VEG), the sequence variations became very low, only 0-0.7%. These results indicated that the GRA20 sequence in type III was more divergence. Phylogenetic analysis of GRA20 sequences using MP and ML methods can differentiate 2 major clonal lineage types (type I and type III) into their respective clusters, indicating the GRA20 gene may represent a novel genetic marker for intraspecific phylogenetic analyses of T. gondii.

  10. Modeling species’ realized climatic niche space and predicting their response to global warming for several western forest species with small geographic distributions

    Science.gov (United States)

    Marcus V. Warwell; Gerald E. Rehfeldt; Nicholas L. Crookston

    2010-01-01

    The Random Forests multiple regression tree was used to develop an empirically based bioclimatic model of the presence-absence of species occupying small geographic distributions in western North America. The species assessed were subalpine larch (Larix lyallii), smooth Arizona cypress (Cupressus arizonica ssp. glabra...

  11. Estimating cyclopoid copepod species richness and geographical distribution (Crustacea across a large hydrographical basin: comparing between samples from water column (plankton and macrophyte stands

    Directory of Open Access Journals (Sweden)

    Gilmar Perbiche-Neves

    2014-06-01

    Full Text Available Species richness and geographical distribution of Cyclopoida freshwater copepods were analyzed along the "La Plata" River basin. Ninety-six samples were taken from 24 sampling sites, twelve sites for zooplankton in open waters and twelve sites for zooplankton within macrophyte stands, including reservoirs and lotic stretches. There were, on average, three species per sample in the plankton compared to five per sample in macrophytes. Six species were exclusive to the plankton, 10 to macrophyte stands, and 17 were common to both. Only one species was found in similar proportions in plankton and macrophytes, while five species were widely found in plankton, and thirteen in macrophytes. The distinction between species from open water zooplankton and macrophytes was supported by nonmetric multidimensional analysis. There was no distinct pattern of endemicity within the basin, and double sampling contributes to this result. This lack of sub-regional faunal differentiation is in accordance with other studies that have shown that cyclopoids generally have wide geographical distribution in the Neotropics and that some species there are cosmopolitan. This contrasts with other freshwater copepods such as Calanoida and some Harpacticoida. We conclude that sampling plankton and macrophytes together provided a more accurate estimate of the richness and geographical distribution of these organisms than sampling in either one of those zones alone.

  12. Patterns of orthopox virus wild rodent hosts in South Germany.

    Science.gov (United States)

    Essbauer, Sandra; Hartnack, Sonja; Misztela, Krystian; Kiessling-Tsalos, Judith; Bäumler, Walter; Pfeffer, Martin

    2009-06-01

    Although cowpox virus (CPXV) infections in a variety of dead-end hosts have been investigated in Germany for more than 50 years, data on species and geographical distribution of CPXV in reservoir hosts are sparse. Here we present the first comprehensive study of 825 rodents that have been collected in Bavaria, Southern Germany. In summary, six different rodent species (Apodemus flavicollis, Myodes glareolus, Microtus arvalis, Apodemus sylvaticus, Microtus agrestis, and Arvicola amphibius) were trapped at three main trapping sites and investigated using a serum neutralization test (SNT). Prevalence of orthopox virus (OPV)-neutralizing antibodies was (with exception of one trapping site) highest in bank voles, ranging from 24.5% to 42.4%; often with SNT titers > or =96. Two up to 25% of yellow-necked mice were OPV sero-positive, but wood mice only at one site with 5.5%. Up to 7.7% of common voles were found to be OPV seroreactive, while M. agrestis and A. amphibius only sporadically showed seroreactivity. Further analyses of a subset of 450 bank voles and yellow-necked mice trapped at one site over a 18-month period revealed that male yellow-necked mice and female gravid yellow-necked mice had significantly more OPV-neutralizing antibodies. Mean body weight and OPV-seroreactivity were significantly negatively associated in male A. flavicollis. This was not due to shorter body length or smaller body mass index, but previously OPV-infected male A. flavicollis had dramatically reduced mean kidney weights. Seroreactivity in female bank voles was positively related to lung weights. We also found that both male yellow-necked mice and male bank voles with positive SNT titers had higher infestation rates with ectoparasites. We here show for the first time that A. flavicollis beside M. glareolus is a hypothetic host for CPXV, and that there are big geographical and spatial variations concerning the seroprevalence in rodent populations in South Germany.

  13. Genetic diversity of Actinobacillus lignieresii isolates from different hosts

    DEFF Research Database (Denmark)

    Kokotovic, Branko; Angen, Øystein; Bisgaard, Magne

    2011-01-01

    Genetic diversity detected by analysis of amplified fragment length polymorphisms (AFLPs) of 54 Actinobacilus lignieresii isolates from different hosts and geographic localities is described. On the basis of variances in AFLP profiles, the strains were grouped in two major clusters; one comprisin...

  14. DIVERSITY AND HOST SPECIFICITY OF AZOLLA CYANOBIONTS(1).

    Science.gov (United States)

    Papaefthimiou, Dimitra; Van Hove, Charles; Lejeune, André; Rasmussen, Ulla; Wilmotte, Annick

    2008-02-01

    A unique, hereditary symbiosis exists between the water fern Azolla and cyanobacteria that reside within a cavity in the dorsal leaf-lobe of the plant. This association has been studied extensively, and questions have frequently been raised regarding the number and diversity of cyanobionts (cyanobacterial symbionts) among the different Azolla strains and species. In this work, denaturating gradient gel electrophoresis (DGGE) and a clone library based on the 16S rRNA gene were used to study the genetic diversity and host specificity of the cyanobionts in 35 Azolla strains covering a wide taxonomic and geographic range. DNA was extracted directly from the cyanobacterial packets, isolated after enzymatic digestion of the Azolla leaves. Our results indicated the existence of different cyanobiont strains among Azolla species, and diversity within a single Azolla species, independent of the geographic origin of the host. Furthermore, the cyanobiont exhibited host-species specificity and showed most divergence between the two sections of genus Azolla, Azolla and Rhizosperma. These findings are in agreement with the recent redefinition of the taxon Azolla cristata within the section Azolla. With regard to the taxonomic status of the cyanobiont, the genus Anabaena of the Nostocaceae family was identified as the closest relative by this work. © 2008 Phycological Society of America.

  15. Geographic distribution of otolaryngologists in the United States.

    Science.gov (United States)

    Vickery, Thad W; Weterings, Robbie; Cabrera-Muffly, Cristina

    2016-06-01

    We conducted a study to determine the demographic traits, training characteristics, and geographic distribution of otolaryngologists in the United States using publicly available data. We then correlated our findings with U.S. census data. Univariate analysis was performed to analyze results, with a p value of <0.05 determined as significant. We used data from the American Board of Otolaryngology's list of 18,587 board-certified allopathic otolaryngologists through 2013 and the American Osteopathic Colleges of Ophthalmology & Otolaryngology-Head & Neck Surgery's list of 428 osteopathic otolaryngologists. From these two databases, 9,642 otolaryngologists met inclusion criteria, which included an active practice in the United States and an age of 70 years and younger. This group was made up of 8,185 men (84.9%) and 1,449 women (15.0%); we were not able to identify the sex of 8 otolaryngologists (0.1%). The median age of the women was significantly lower than that of the men (54 vs. 48 yr; p < 0.001). A total of 8,510 otolaryngologists (88.3%) graduated from a U.S. allopathic medical school, and 8,520 (88.4%) graduated from a U.S. allopathic residency program. We determined that 25.9% of otolaryngologists established their practice in the same metropolitan statistical area where they completed their residency training. Older practitioners (p < 0.001) and women (p < 0.001) were significantly more likely to stay in the same area than younger physicians and men. In terms of population, 61.8% of the otolaryngologists practiced in metropolitan areas with more than 1 million residents; by comparison, these areas represent only 55.3% of the total U.S. population, indicating that otolaryngologists are over-represented in larger U.S. cities.

  16. Effect of age, photoperiod and host availability on the parasitism behavior of Oomyzus sokolowskii Kurdjumov (Hymenoptera: Eulophidae)

    International Nuclear Information System (INIS)

    Silva-Torres, Christian S.A.; Barros, Reginaldo; Torres, Jorge B.

    2009-01-01

    The high reproduction rate, potential to cause damage, wide geographic distribution and resistance to insecticides of Plutella xylostella (L.) makes difficult its efficient control. However, larvae and pupae of this pest are naturally parasitized by Oomyzus Sokolowskii (Kurdjumov), providing opportunities to improve the natural parasitism. This study investigated the effects of the age of adult parasitoids, host availability and time of exposure on O. sokolowskii parasitism behavior. The number of larvae encounters by parasitoid females and the parasitism rate increased with parasitoid age up to 96 h. The parasitization was higher when wasps received a constant number of hosts daily in comparison with a random number (13.3 versus 8.9 larvae parasitized). Female parasitization activity was maintained up to the age of 20 days in both treatments and exhibited similar longevity (constant host = 33.5 d; and random host = 34.7 d). The progeny produced per female and the number of parasitoids emerged per host significantly decreased as wasps aged. There was no significant effect of the light regime (12 h darkness or 12 h light exposure) on the parasitization, although parasitoid was more active after 3 h of light exposure. Therefore, further studies on field application of O. sokolowskii should consider the release of 48 h - to 72 h - old parasitoids at dawn as a way to increase the success of host parasitization. (author)

  17. XNsim: Internet-Enabled Collaborative Distributed Simulation via an Extensible Network

    Science.gov (United States)

    Novotny, John; Karpov, Igor; Zhang, Chendi; Bedrossian, Nazareth S.

    2007-01-01

    In this paper, the XNsim approach to achieve Internet-enabled, dynamically scalable collaborative distributed simulation capabilities is presented. With this approach, a complete simulation can be assembled from shared component subsystems written in different formats, that run on different computing platforms, with different sampling rates, in different geographic locations, and over singlelmultiple networks. The subsystems interact securely with each other via the Internet. Furthermore, the simulation topology can be dynamically modified. The distributed simulation uses a combination of hub-and-spoke and peer-topeer network topology. A proof-of-concept demonstrator is also presented. The XNsim demonstrator can be accessed at http://www.jsc.draver.corn/xn that hosts various examples of Internet enabled simulations.

  18. The Evolutionary Relationships between Endosymbiotic Green Algae of Paramecium bursaria Syngens Originating from Different Geographical Locations.

    Science.gov (United States)

    Zagata, Patrycja; Greczek-Stachura, Magdalena; Tarcz, Sebastian; Rautian, Maria

    2016-01-01

    Paramecium bursaria (Ehrenberg 1831), a freshwater ciliate, typically harbors hundreds of green algal symbionts inside the cell. The aim of present study was the molecular identification of newly analyzed P. bursaria symbionts. The second aspect of the present survey was testing a hypothesis whether endosymbionts prefer the specified syngen of the host, and the specified geographical distribution. Ten strains of endosymbionts isolated from strains of P. bursaria originating from different geographical locations were studied. We analyzed for the first time, both the fragment of plastid genome containing 3'rpl36-5' infA genes and a fragment of a nuclear gene encoding large subunit ribosomal RNA (LSU rDNA). The analysis of the LSU rDNA sequences showed the existence of 3 haplotypes and the haplotype diversity of 0.733, and 8 haplotypes for the 3'rpl36-5' infA gene fragment and haplotype diversity of 0.956. The endosymbionts isolated from P. bursaria strains were identified as Chlorella vulgaris, Ch. variabilis and Micractinium conductrix. There was no correlation between the syngen of P. bursaria and the species of endosymbiont.

  19. The identity and distribution of Fiorinia phantasma (Cockerell & Robinson) (Hemiptera: Coccomorpha: Diaspididae), with a new synonym.

    Science.gov (United States)

    Watson, Gillian W; Williams, Douglas J; Miller, Douglass R

    2015-11-25

    The morphologies of Fiorinia phantasma (Cockerell & Robinson) (Hemiptera: Coccomorpha: Diaspididae) and F. coronata Williams & Watson are reviewed, and the name F. coronata is placed as a junior synonym of the name F. phantasma syn. n. The known geographical distribution and host range of F. phantasma is documented and discussed. An identification key to 12 of the 16 species of Fiorinia known from the Australasian, Nearctic and Neotropical Regions is provided.

  20. Canine distemper virus - a morbillivirus in search of new hosts?

    NARCIS (Netherlands)

    T.C. Harder (Timm); A.D.M.E. Osterhaus (Albert)

    1997-01-01

    textabstractCanine distemper morbillivirus (CDV) induces a multisystemic, often fatal disease in a wide and seemingly expanding host range among the Carnivora. Several genotypes of an otherwise monotypic virus species co-circulate in a geographically restricted pattern. Interspecies transmissions

  1. Climate Controls AM Fungal Distributions from Global to Local Scales

    Science.gov (United States)

    Kivlin, S. N.; Hawkes, C.; Muscarella, R.; Treseder, K. K.; Kazenel, M.; Lynn, J.; Rudgers, J.

    2016-12-01

    Arbuscular mycorrhizal (AM) fungi have key functions in terrestrial biogeochemical processes; thus, determining the relative importance of climate, edaphic factors, and plant community composition on their geographic distributions can improve predictions of their sensitivity to global change. Local adaptation by AM fungi to plant hosts, soil nutrients, and climate suggests that all of these factors may control fungal geographic distributions, but their relative importance is unknown. We created species distribution models for 142 AM fungal taxa at the global scale with data from GenBank. We compared climate variables (BioClim and soil moisture), edaphic variables (phosphorus, carbon, pH, and clay content), and plant variables using model selection on models with (1) all variables, (2) climatic variables only (including soil moisture) and (3) resource-related variables only (all other soil parameters and NPP) using the MaxEnt algorithm evaluated with ENMEval. We also evaluated whether drivers of AM fungal distributions were phylogenetically conserved. To test whether global correlates of AM fungal distributions were reflected at local scales, we then surveyed AM fungi in nine plant hosts along three elevation gradients in the Upper Gunnison Basin, Colorado, USA. At the global scale, the distributions of 55% of AM fungal taxa were affected by both climate and soil resources, whereas 16% were only affected by climate and 29% were only affected by soil resources. Even for AM fungi that were affected by both climate and resources, the effects of climatic variables nearly always outweighed those of resources. Soil moisture and isothermality were the main climatic and NPP and soil carbon the main resource related factors influencing AM fungal distributions. Distributions of closely related AM fungal taxa were similarly affected by climate, but not by resources. Local scale surveys of AM fungi across elevations confirmed that climate was a key driver of AM fungal

  2. Implications of China's future bride shortage for the geographical distribution and social protection needs of never-married men.

    Science.gov (United States)

    Sharygin, Ethan; Ebenstein, Avraham; Das Gupta, Monica

    2013-01-01

    Because sex ratios at birth have risen sharply in China in recent decades, an increasing proportion of men will be unable to find a bride, and will face old age without the support of a wife and children. We project the proportions of never-married men and their geographical distribution in China in the coming decades. Our projections assume that two tendencies in current marriage patterns will persist: that women will continue to migrate to wealthier areas and to prefer men with better prospects. We find that, by 2030, more than 20 per cent of men in China aged 30-39 will never have married, and that the proportion will be especially high among poor men in low-income provinces that are least able to provide social protection programmes. The projected geographic concentration of bachelors could be socially disruptive, and the results suggest a need to expand the coverage and central financing of social protection programmes.

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

    Science.gov (United States)

    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.

  4. Geographical differences in food allergy.

    Science.gov (United States)

    Bartra, Joan; García-Moral, Alba; Enrique, Ernesto

    2016-06-01

    Food allergy represents a health problem worldwide and leads to life-threatening reactions and even impairs quality of life. Epidemiological data during the past decades is very heterogeneous because of the use of different diagnostic procedures, and most studies have only been performed in specific geographical areas. The aim of this article is to review the available data on the geographical distribution of food allergies at the food source and molecular level and to link food allergy patterns to the aeroallergen influence in each area. Systematic reviews, meta-analysis, studies performed within the EuroPrevall Project and EAACI position papers regarding food allergy were analysed. The prevalence of food allergy sensitization differs between geographical areas, probably as a consequence of differences among populations, their habits and the influence of the cross-reactivity of aeroallergens and other sources of allergens. Geographical differences in food allergy are clearly evident at the allergenic molecular level, which seems to be directly influenced by the aeroallergens of each region and associated with specific clinical patterns.

  5. Large-scale geographic variation in distribution and abundance of Australian deep-water kelp forests.

    Directory of Open Access Journals (Sweden)

    Ezequiel M Marzinelli

    Full Text Available Despite the significance of marine habitat-forming organisms, little is known about their large-scale distribution and abundance in deeper waters, where they are difficult to access. Such information is necessary to develop sound conservation and management strategies. Kelps are main habitat-formers in temperate reefs worldwide; however, these habitats are highly sensitive to environmental change. The kelp Ecklonia radiate is the major habitat-forming organism on subtidal reefs in temperate Australia. Here, we provide large-scale ecological data encompassing the latitudinal distribution along the continent of these kelp forests, which is a necessary first step towards quantitative inferences about the effects of climatic change and other stressors on these valuable habitats. We used the Autonomous Underwater Vehicle (AUV facility of Australia's Integrated Marine Observing System (IMOS to survey 157,000 m2 of seabed, of which ca 13,000 m2 were used to quantify kelp covers at multiple spatial scales (10-100 m to 100-1,000 km and depths (15-60 m across several regions ca 2-6° latitude apart along the East and West coast of Australia. We investigated the large-scale geographic variation in distribution and abundance of deep-water kelp (>15 m depth and their relationships with physical variables. Kelp cover generally increased with latitude despite great variability at smaller spatial scales. Maximum depth of kelp occurrence was 40-50 m. Kelp latitudinal distribution along the continent was most strongly related to water temperature and substratum availability. This extensive survey data, coupled with ongoing AUV missions, will allow for the detection of long-term shifts in the distribution and abundance of habitat-forming kelp and the organisms they support on a continental scale, and provide information necessary for successful implementation and management of conservation reserves.

  6. Distribution patterns of zoochlorellae and zooxanthellae hosted by two Pacific Northeast anemones, Anthopleura elegantissima and A. xanthogrammica.

    Science.gov (United States)

    Bates, Amanda E; McLean, Lily; Laing, Patrick; Raeburn, Lisa A; Hare, Crystal

    2010-06-01

    This study investigated patterns in the relative abundance of two photosynthetic algal symbionts, zoochlorellae (ZC) and zooxanthellae (ZX), hosted by two temperate anemones, Anthopleura elegantissima and A. xanthogrammica. Previous studies have documented varying proportions of each symbiont along environmental gradients, presumably determined by their respective physiological capabilities. To test for differences in the algal type between the two host species, we sampled anemone tissues (tentacle or tentacle and body column) of similarly sized polyps that were located close together in multiple habitats: tidepools, crevices, underneath rock ledges, and along natural light gradients in caves. The ZC-A. elegantissima symbiosis was rare on the west coast of Vancouver Island, British Columbia, Canada. Even in low-irradiance habitats, ZC were the dominant algae hosted by A. xanthogrammica, while nearby A. elegantissima hosted ZX or was algae-free. As a first step in determining whether symbiont growth rates differed between the two host species, we quantified mitotic index (MI), the percentage of cells with division furrows, under artificial light and in the field by simultaneously sampling tentacles from both species. MI was more stable in A. elegantissima: the MI of ZX isolated from the tentacles of A. xanthogrammica was slightly higher at a light level of 80 micromol quanta m(-2) s(-1) than it was for ZX from A. elegantissima (respectively, 7.3 vs. 6.2) and relatively lower at 40 micromol quanta m(-2) s(-1) (3.9 vs. 5.6). Our data indicate host-specific differences in symbiont distributions and MI when extrinsic physical parameters were similar.

  7. Geographic distribution and host plants of Raoiella indica and associated mite species in northern Venezuela.

    Science.gov (United States)

    Vásquez, Carlos; de Moraes, Gilberto J

    2013-05-01

    The red palm mite (RPM), Raoiella indica Hirst (Acari: Tenuipalpidae), is an invasive pest in the New World, where it is currently considered a serious threat to coconut and banana crops. It was first reported from northern Venezuela in 2007. To determine its current distribution in this country, surveys were carried out from October 2008 to April 2010 on coconut (Cocos nucifera L.), banana (Musa spp.), ornamental plants and weeds in northern Venezuela. Higher population levels of RPM were registered on commercial coconut farms in Falcón and Sucre states but also on other plant species naturally growing along the coastal line in Anzoategui, Aragua, Carabobo, Monagas and Nueva Esparta states. Out of 34 botanical species evaluated, all RPM stages were observed only on eight arecaceous, one musaceous and one streliziaceous species, indicating that the pest developed and reproduced only on these plants. Mite specimens found on weeds were considered spurious events, as immature stages of the pest were never found on these. Amblyseius largoensis (Muma) (Acari: Phytoseiidae) was the most frequent predatory mite associated with RPM in all sampling sites. The results indicate that RPM has spread to extensive areas of northern Venezuela since its initial detection in Güiria, Sucre state. Considering the report of this pest mite in northern Brazil in the late 2009, additional samplings in southern Venezuela should be carried out, to evaluate the possible presence of RPM also in that region.

  8. Temporal changes in the geographic distribution, elevation, and potential origin of the Martian outflow channels

    Science.gov (United States)

    Tribe, S.; Clifford, S. M.

    1993-01-01

    Observational evidence of outflow channel activity on Mars suggests that water was abundant in the planet's early crust. However, with the decline in the planet's internal heat flow, a freezing front developed within the regolith that propagated downward with time and acted as a thermodynamic sink for crustal H2O. One result of this thermal evolution is that, if the initial inventory of water on Mars was small, the cryosphere may have grown to the point where all the available water was taken up as ground ice. Alternatively, if the inventory of H2O exceeds the current pore volume of the cryosphere, then Mars has always possessed extensive bodies of subpermafrost groundwater. We have investigated the relative age, geographic distribution, elevation, and geologic setting of the outflow channels in an effort to accomplish the following: (1) identify possible modes of origin and evolutionary trends in their formation; (2) gain evidence regarding the duration and spatial distribution of groundwater in the crust; and (3) better constraint estimates of the planetary inventory of H2O.

  9. Translocation 1;7 in dyshematopoiesis: possibly induced with a nonrandom geographic distribution

    International Nuclear Information System (INIS)

    Scheres, J.M.; Hustinx, T.W.; Holdrinet, R.S.; Geraedts, J.P.; Hagemeijer, A.; van der Blij-Philipsen, M.

    1984-01-01

    Eight patients with various hematologic disorders had an identical chromosomal aberration in their bone marrow or unstimulated peripheral blood, a translocation t(1;7) interpreted as t(1;7)(p11;p11). The translocation chromosome replaced one normal chromosome number7; therefore, the karyotype of the abnormal cells was trisomic for 1q and monosomic for 7q. Including four cases from the literature, a total of 12 patients (4 women, 8 men) with this translocation are known at the moment. The translocation does not seem to be associated with a specific disorder, but almost all patients had a preleukemic syndrome during some stage of their disease. It is very remarkable that 11 of the 12 patients lived in the Netherlands, and 7 patients had a history of iatrogenic exposure to alkylating agents or irradiation; one patient was a radiation worker and another one had a history of toxic exposure to chloramphenicol. It is suggested, therefore, that the t(1;7) is a possibly induced chromosomal aberration with a clearly nonrandom geographic distribution

  10. Geographic variability in elevation and topographic constraints on the distribution of native and nonnative trout in the Great Basin

    Science.gov (United States)

    Warren, Dana R.; Dunham, Jason B.; Hockman-Wert, David

    2014-01-01

    Understanding local and geographic factors influencing species distributions is a prerequisite for conservation planning. Our objective in this study was to model local and geographic variability in elevations occupied by native and nonnative trout in the northwestern Great Basin, USA. To this end, we analyzed a large existing data set of trout presence (5,156 observations) to evaluate two fundamental factors influencing occupied elevations: climate-related gradients in geography and local constraints imposed by topography. We applied quantile regression to model upstream and downstream distribution elevation limits for each trout species commonly found in the region (two native and two nonnative species). With these models in hand, we simulated an upstream shift in elevation limits of trout distributions to evaluate potential consequences of habitat loss. Downstream elevation limits were inversely associated with latitude, reflecting regional gradients in temperature. Upstream limits were positively related to maximum stream elevation as expected. Downstream elevation limits were constrained topographically by valley bottom elevations in northern streams but not in southern streams, where limits began well above valley bottoms. Elevation limits were similar among species. Upstream shifts in elevation limits for trout would lead to more habitat loss in the north than in the south, a result attributable to differences in topography. Because downstream distributions of trout in the north extend into valley bottoms with reduced topographic relief, trout in more northerly latitudes are more likely to experience habitat loss associated with an upstream shift in lower elevation limits. By applying quantile regression to relatively simple information (species presence, elevation, geography, topography), we were able to identify elevation limits for trout in the Great Basin and explore the effects of potential shifts in these limits that could occur in response to changing

  11. Gastrointestinal parasites of the Common Eider (Somateria mollissima) – Seasonal, geographical and host related variations in the parasite burdens of two distinct Danish populations

    DEFF Research Database (Denmark)

    Jensen, Marie Stengaard; Chriél, Mariann; Al-Sabi, Mohammad Nafi Solaiman

    Due to a recent decline in number of Common Eiders (Somateria mollissima) in Denmark, prevalence, intensity and composition of the gastrointestinal helminth fauna of Common Eiders from two distinct colonies were examined to establish reference data of the helminth fauna of apparently healthy birds....... Furthermore, seasonal, geographical and host related variations in helminth composition were studied. The birds were collected November 2010 to January 2012. Included were a total of 157 eiders from Jutland (N=103) and Zealand (N=54) respectively, comprising 54 males and 102 females of which 20 were gathered...... during the nesting period. The study is ongoing, and so far most parasites have only been identified to the family level. Eight trematode families, two nematode families, one acanthocephala and one cestode family were identified. Intensities of infections were primarily influenced by age of the birds...

  12. Geographic information system for pigweed distribution in the US Southeast

    Science.gov (United States)

    In the southeastern United States, pigweeds have become troublesome weeds in agricultural systems. To implement management strategies to control them, agriculturalists need information on areas affected by pigweeds. Geographic information systems (GIS) afford users the ability to evaluate agricult...

  13. Allopatric tuberculosis host-pathogen relationships are associated with greater pulmonary impairment.

    Science.gov (United States)

    Pasipanodya, Jotam G; Moonan, Patrick K; Vecino, Edgar; Miller, Thaddeus L; Fernandez, Michel; Slocum, Philip; Drewyer, Gerry; Weis, Stephen E

    2013-06-01

    Host pathogen relationships can be classified as allopatric, when the pathogens originated from separate, non-overlapping geographic areas from the host; or sympatric, when host and pathogen shared a common ancestral geographic location. It remains unclear if host-pathogen relationships, as defined by phylogenetic lineage, influence clinical outcome. We sought to examine the association between allopatric and sympatric phylogenetic Mycobacterium tuberculosis lineages and pulmonary impairment after tuberculosis (PIAT). Pulmonary function tests were performed on patients 16 years of age and older who had received ≥20 weeks of treatment for culture-confirmed M. tuberculosis complex. Forced Expiratory Volume in 1 min (FEV1) ≥80%, Forced Vital Capacity (FVC) ≥80% and FEV1/FVC >70% of predicted were considered normal. Other results defined pulmonary impairment. Spoligotype and 12-locus mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) were used to assign phylogenetic lineage. PIAT severity was compared between host-pathogen relationships which were defined by geography and ethnic population. We used multivariate logistic regression modeling to calculate adjusted odds ratios (aOR) between phylogenetic lineage and PIAT. Self-reported continental ancestry was correlated with Mycobacterium. tuberculosis lineage (pallopatric host-pathogen relationships and PIAT was 1.8 (95% confidence interval [CI]: 1.1, 2.9) compared to sympatric relationships. Smoking >30 pack-years was also associated with PIAT (aOR: 3.2; 95% CI: 1.5, 7.2) relative to smoking allopatric-host-pathogen relationship were more likely to have PIAT than patients with disease from sympatric-host-pathogen relationship infection. Further study of this association may identify ways that treatment and preventive efforts can be tailored to specific lineages and racial/ethnic populations. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Ring distributions leading to species formation: a global topographic analysis of geographic barriers associated with ring species

    Directory of Open Access Journals (Sweden)

    Monahan William B

    2012-03-01

    relative importance of features that define barriers, (ii can be replicated using any kind of continuously distributed environmental variable, and (iii generates spatially explicit hypotheses of geographic species formation. The methods developed here - combined with study of the geographical ecology and genetics of taxa in their environments - should enable recognition of ring species phenomena throughout the world.

  15. Comprehensive Monitoring for Heterogeneous Geographically Distributed Storage

    Energy Technology Data Exchange (ETDEWEB)

    Ratnikova, N. [Fermilab; Karavakis, E. [CERN; Lammel, S. [Fermilab; Wildish, T. [Princeton U.

    2015-12-23

    Storage capacity at CMS Tier-1 and Tier-2 sites reached over 100 Petabytes in 2014, and will be substantially increased during Run 2 data taking. The allocation of storage for the individual users analysis data, which is not accounted as a centrally managed storage space, will be increased to up to 40%. For comprehensive tracking and monitoring of the storage utilization across all participating sites, CMS developed a space monitoring system, which provides a central view of the geographically dispersed heterogeneous storage systems. The first prototype was deployed at pilot sites in summer 2014, and has been substantially reworked since then. In this paper we discuss the functionality and our experience of system deployment and operation on the full CMS scale.

  16. Characterization of the papilionoid-Burkholderia interaction in the Fynbos biome: The diversity and distribution of beta-rhizobia nodulating Podalyria calyptrata (Fabaceae, Podalyrieae).

    Science.gov (United States)

    Lemaire, Benny; Van Cauwenberghe, Jannick; Verstraete, Brecht; Chimphango, Samson; Stirton, Charles; Honnay, Olivier; Smets, Erik; Sprent, Janet; James, Euan K; Muasya, A Muthama

    2016-02-01

    The South African Fynbos soils are renowned for nitrogen-fixing Burkholderia associated with diverse papilionoid legumes of the tribes Crotalarieae, Hypocalypteae, Indigofereae, Phaseoleae and Podalyrieae. However, despite numerous rhizobial studies in the region, the symbiotic diversity of Burkholderia has not been investigated in relation to a specific host legume and its geographical provenance. This study analyzed the diversity of nodulating strains of Burkholderia from the legume species Podalyria calyptrata. Diverse lineages were detected that proved to be closely related to Burkholderia taxa, originating from hosts in other legume tribes. By analyzing the genetic variation of chromosomal (recA) and nodulation (nodA) sequence data in relation to the sampling sites we assessed the geographical distribution patterns of the P. calyptrata symbionts. Although we found a degree of genetically differentiated rhizobial populations, a correlation between genetic (recA and nodA) and geographic distances among populations was not observed, suggesting high rates of dispersal and rhizobial colonization within Fynbos soils. Copyright © 2015 Elsevier GmbH. All rights reserved.

  17. Addressing the unequal geographic distribution of specialist doctors in indonesia: the role of the private sector and effectiveness of current regulations.

    Science.gov (United States)

    Meliala, Andreasta; Hort, Krishna; Trisnantoro, Laksono

    2013-04-01

    As in many countries, the geographic distribution of the health workforce in Indonesia is unequal, with a concentration in urban and more developed areas, and a scarcity in rural and remote areas. There is less information on the distribution of specialist doctors, yet inequalities in their distribution could compromise efforts to achieve universal coverage by 2014. This paper uses data from 2007 and 2008 to describe the geographic distribution of specialist doctors in Indonesia, and to examine two key factors that influence the distribution and are targets of current policies: sources of income for specialist doctors, and specialist doctor engagement in private practice. The data demonstrates large differences in the ratio of specialist doctors to population among the provinces of Indonesia, with higher ratios on the provinces of the islands of Java, and much lower ratios on the more remote provinces in eastern Indonesia. Between 65% and 80% of specialist doctors' income derives from private practice in non-state hospitals or private clinics. Despite regulations limiting practice locations to three, most specialists studied in a provincial capital city were working in more than three locations, with some working in up to 7 locations, and spending only a few hours per week in their government hospital practice. Our study demonstrates that the current regulatory policies and financial incentives have not been effective in addressing the maldistribution of specialist doctors in a context of a growing private sector and predominance of doctors' income from private sources. A broader and more integrated policy approach, including more innovative service delivery strategies for rural and remote areas, is recommended. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. A spatial model of mosquito host-seeking behavior.

    Directory of Open Access Journals (Sweden)

    Bree Cummins

    Full Text Available Mosquito host-seeking behavior and heterogeneity in host distribution are important factors in predicting the transmission dynamics of mosquito-borne infections such as dengue fever, malaria, chikungunya, and West Nile virus. We develop and analyze a new mathematical model to describe the effect of spatial heterogeneity on the contact rate between mosquito vectors and hosts. The model includes odor plumes generated by spatially distributed hosts, wind velocity, and mosquito behavior based on both the prevailing wind and the odor plume. On a spatial scale of meters and a time scale of minutes, we compare the effectiveness of different plume-finding and plume-tracking strategies that mosquitoes could use to locate a host. The results show that two different models of chemotaxis are capable of producing comparable results given appropriate parameter choices and that host finding is optimized by a strategy of flying across the wind until the odor plume is intercepted. We also assess the impact of changing the level of host aggregation on mosquito host-finding success near the end of the host-seeking flight. When clusters of hosts are more tightly associated on smaller patches, the odor plume is narrower and the biting rate per host is decreased. For two host groups of unequal number but equal spatial density, the biting rate per host is lower in the group with more individuals, indicative of an attack abatement effect of host aggregation. We discuss how this approach could assist parameter choices in compartmental models that do not explicitly model the spatial arrangement of individuals and how the model could address larger spatial scales and other probability models for mosquito behavior, such as Lévy distributions.

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

    NARCIS (Netherlands)

    S. Tims (Sebastian); W.J.B. van Wamel (Willem); H.P. Endtz (Hubert); A.F. van Belkum (Alex); M.H. Kayser (Manfred)

    2009-01-01

    textabstractHuman 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

  20. Molecular characterization of Babesia peircei and Babesia ugwidiensis provides insight into the evolution and host specificity of avian piroplasmids

    Directory of Open Access Journals (Sweden)

    Michael J. Yabsley

    2017-12-01

    Full Text Available There are 16 recognized species of avian-infecting Babesia spp. (Piroplasmida: Babesiidae. While the classification of piroplasmids has been historically based on morphological differences, geographic isolation and presumed host and/or vector specificities, recent studies employing gene sequence analysis have provided insight into their phylogenetic relationships and host distribution and specificity. In this study, we analyzed the sequences of the 18S rRNA gene and ITS-1 and ITS-2 regions of two Babesia species from South African seabirds: Babesia peircei from African penguins (Spheniscus demersus and Babesia ugwidiensis from Bank and Cape cormorants (Phalacrocorax neglectus and P. capensis, respectively. Our results show that avian Babesia spp. are not monophyletic, with at least three distinct phylogenetic groups. B. peircei and B. ugwidiensis are closely related, and fall within the same phylogenetic group as B. ardeae (from herons Ardea cinerea, B. poelea (from boobies Sula spp. and B. uriae (from murres Uria aalge. The validity of B. peircei and B. ugwidiensis as separate species is corroborated by both morphological and genetic evidence. On the other hand, our results indicate that B. poelea might be a synonym of B. peircei, which in turn would be a host generalist that infects seabirds from multiple orders. Further studies combining morphological and molecular methods are warranted to clarify the taxonomy, phylogeny and host distribution of avian piroplasmids. Keywords: Africa, Babesia, Piroplasmida, Phalacrocoracidae, Spheniscidae, Tick-borne pathogen

  1. New records and update on the geographic distribution of Clitocybula lignicola (Lj.N. Vassiljeva) E.F. Malysheva & O.V. Morozova (Basidiomycota: Agaricales) in Russia

    OpenAIRE

    Shiryaeva, Olga

    2016-01-01

    Clitocybula lignicola is predominantly distributed in the Asian part of Russia. In Europe it was found only in the Urals (Komi Republic, Russia). Two new localities are situated in the northwestern part of Vologda Region (Russia). These are the first records of this species from the East European Plain, as well as the most western ones known in Europe. New records extend the geographic distribution of C. lignicola 1,204 km west of the closest site in the Urals. An updated distribution map for...

  2. Emergence of a New Population of Rathayibacter toxicus: An Ecologically Complex, Geographically Isolated Bacterium

    OpenAIRE

    Arif, Mohammad; Busot, Grethel Y.; Mann, Rachel; Rodoni, Brendan; Liu, Sanzhen; Stack, James P.

    2016-01-01

    Rathayibacter toxicus is a gram-positive bacterium that infects the floral parts of several Poaceae species in Australia. Bacterial ooze is often produced on the surface of infected plants and bacterial galls are produced in place of seed. R. toxicus is a regulated plant pathogen in the U.S. yet reliable detection and diagnostic tools are lacking. To better understand this geographically-isolated plant pathogen, genetic variation as a function of geographic location, host species, and date of...

  3. Combining Inferential and Deductive Approaches to Estimate the Potential Geographical Range of the Invasive Plant Pathogen, Phytophthora ramorum

    Science.gov (United States)

    Ireland, Kylie B.; Hardy, Giles E. St. J.; Kriticos, Darren J.

    2013-01-01

    Phytophthora ramorum, an invasive plant pathogen of unknown origin, causes considerable and widespread damage in plant industries and natural ecosystems of the USA and Europe. Estimating the potential geographical range of P. ramorum has been complicated by a lack of biological and geographical data with which to calibrate climatic models. Previous attempts to do so, using either invaded range data or surrogate species approaches, have delivered varying results. A simulation model was developed using CLIMEX to estimate the global climate suitability patterns for establishment of P. ramorum. Growth requirements and stress response parameters were derived from ecophysiological laboratory observations and site-level transmission and disease factors related to climate data in the field. Geographical distribution data from the USA (California and Oregon) and Norway were reserved from model-fitting and used to validate the models. The model suggests that the invasion of P. ramorum in both North America and Europe is still in its infancy and that it is presently occupying a small fraction of its potential range. Phytophthora ramorum appears to be climatically suited to large areas of Africa, Australasia and South America, where it could cause biodiversity and economic losses in plant industries and natural ecosystems with susceptible hosts if introduced. PMID:23667628

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

    Science.gov (United States)

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

    2010-09-01

    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.

  5. Spatial distribution of dengue disease in municipality of Mossoró, Rio Grande do Norte, using the Geographic Information System

    Directory of Open Access Journals (Sweden)

    Francisco Narcísio Bessa Júnior

    2013-09-01

    Full Text Available The dengue viral infection is one of the most relevant vector-borne diseases in the world. The disease can manifest in a variety of forms, from asymptomatic to a condition of dengue hemorrhagic fever (DHF. The last reported cases in Brazil correspond to 80% of the cases reported in the Americas, which emphasizes the magnitude of the problem. This study was conducted using Geographic Information System (GIS techniques, in order to evaluate the spatial distribution of the disease in the urban area of Mossoró, Rio Grande do Norte. In the period between 2001 and 2007, 867 new cases were listed. About 85.7% of the addresses were georeferenced, with a larger number of cases, 14.8%, in the neighborhoods of Santo Antônio and Santa Delmira (north region, and 11.7% in the neighborhoods of Conjunto Vingt-Rosado and Alto de São Manoel (east region. There were 18 confirmed cases of dengue hemorrhagic fever associated with regions with the highest incidence of classic cases of the disease. The use of Geographic Information System (GIS proved a great benefit for better visualization of the endemic, especially in elucidating the actual distribution of dengue cases in the county and providing an effective tool for planning the monitoring of the disease at a local level.

  6. Using Metadata to Build Geographic Information Sharing Environment on Internet

    Directory of Open Access Journals (Sweden)

    Chih-hong Sun

    1999-12-01

    Full Text Available Internet provides a convenient environment to share geographic information. Web GIS (Geographic Information System even provides users a direct access environment to geographic databases through Internet. However, the complexity of geographic data makes it difficult for users to understand the real content and the limitation of geographic information. In some cases, users may misuse the geographic data and make wrong decisions. Meanwhile, geographic data are distributed across various government agencies, academic institutes, and private organizations, which make it even more difficult for users to fully understand the content of these complex data. To overcome these difficulties, this research uses metadata as a guiding mechanism for users to fully understand the content and the limitation of geographic data. We introduce three metadata standards commonly used for geographic data and metadata authoring tools available in the US. We also review the current development of geographic metadata standard in Taiwan. Two metadata authoring tools are developed in this research, which will enable users to build their own geographic metadata easily.[Article content in Chinese

  7. Update of host plant list of Anastrepha fraterculus and Ceratitis capitata in Argentina

    International Nuclear Information System (INIS)

    Orono, Luis E.; Albornoz-Medina, Patricia; Nunez-Campero, Segundo; Nieuwenhove, Guido A. van; Bezdjian, Laura P.; Martin, Cristina B.; Schliserman, Pablo; Ovruski, Sergio M.

    2006-01-01

    The study displays a complete picture of the host range of the two economically important fruit fly species in Argentina, the native Anastrepha fraterculus (Wiedemann) (South American Fruit Fly) and the exotic Ceratitis capitata (Wiedemann) (Mediterranean Fruit Fly or Medfly). This work provides information on the fruit type of each plant species, associated tephritid species, habitat where the fruit was collected, geographical location of each fruit collection area (latitude, longitude, and altitude), phyto geographic regions where each area is located, as well as a general description of the landscape characteristics of those habitats where the fruit samples with fly larvae were collected. A complete, detailed bibliographic review was made in order to provide all the relevant information needed for host use in natural setting. (author)

  8. Update of host plant list of Anastrepha fraterculus and Ceratitis capitata in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Orono, Luis E.; Albornoz-Medina, Patricia; Nunez-Campero, Segundo; Nieuwenhove, Guido A. van; Bezdjian, Laura P.; Martin, Cristina B.; Schliserman, Pablo; Ovruski, Sergio M. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Tucuman (Argentina). Planta Piloto de Procesos Industriales Microbiologicos y Biotecnologia. Div. Control Biologico de Plagas

    2006-07-01

    The study displays a complete picture of the host range of the two economically important fruit fly species in Argentina, the native Anastrepha fraterculus (Wiedemann) (South American Fruit Fly) and the exotic Ceratitis capitata (Wiedemann) (Mediterranean Fruit Fly or Medfly). This work provides information on the fruit type of each plant species, associated tephritid species, habitat where the fruit was collected, geographical location of each fruit collection area (latitude, longitude, and altitude), phyto geographic regions where each area is located, as well as a general description of the landscape characteristics of those habitats where the fruit samples with fly larvae were collected. A complete, detailed bibliographic review was made in order to provide all the relevant information needed for host use in natural setting. (author)

  9. Host preferences support the prominent role of Hyalomma ticks in the ecology of Crimean-Congo hemorrhagic fever.

    Directory of Open Access Journals (Sweden)

    Jessica R Spengler

    2018-02-01

    Full Text Available Crimean-Congo hemorrhagic fever virus (CCHFV is a tick-borne zoonotic agent that is maintained in nature in an enzootic vertebrate-tick-vertebrate cycle. Hyalomma genus ticks have been implicated as the main CCHFV vector and are key in maintaining silent endemic foci. However, what contributes to their central role in CCHFV ecology is unclear. To assess the significance of host preferences of ticks in CCHFV ecology, we performed comparative analyses of hosts exploited by 133 species of ticks; these species represent 5 genera with reported geographical distribution over the range of CCHFV. We found that the composition of vertebrate hosts on which Hyalomma spp. feed is different than for other tick genera. Immatures of the genus Hyalomma feed preferentially on species of the orders Rodentia, Lagomorpha, and the class Aves, while adults concentrate mainly on the family Bovidae. With the exception of Aves, these hosts include the majority of the vertebrates consistently reported to be viremic upon CCHFV infection. While other tick genera also feed on these hosts, Hyalomma spp. almost completely concentrate their populations on them. Hyalomma spp. feed on less phylogenetically diverse hosts than any other tick genus, implying that this network of hosts has a low resilience. Indeed, removing the most prominent hosts quickly collapsed the network of parasitic interactions. These results support the intermittent activity of CCHFV foci: likely, populations of infected Hyalomma spp. ticks exceed the threshold of contact with humans only when these critical hosts reach adequate population density, accounting for the sporadic occurence of clinical tick-transmitted cases. Our data describe the association of vertebrate host preferences with the role of Hyalomma spp. ticks in maintaining endemic CCHFV foci, and highlight the importance of host-tick dynamics in pathogen ecology.

  10. Glastonbury Festival 2007: The Socio-Economic Impacts on the Host Community

    OpenAIRE

    Rose, Eleanor

    2008-01-01

    Event tourism, particularly festival tourism, is increasingly becoming a focus for tourism research. There are numerous impacts of festival tourism to the tourism industry and they often have numerous effects upon the host community. This research investigates the economic and social impacts of Glastonbury Festival 2007 on the host community. The research estimates a total economic impact on the immediate and the wider geographical area and gains an insight into the social impacts of the F...

  11. Zika virus, vectors, reservoirs, amplifying hosts, and their potential to spread worldwide: what we know and what we should investigate urgently.

    Science.gov (United States)

    Vorou, Rengina

    2016-07-01

    The widespread epidemic of Zika virus infection in South and Central America and the Caribbean in 2015, along with the increased incidence of microcephaly in fetuses born to mothers infected with Zika virus and the potential for worldwide spread, indicate the need to review the current literature regarding vectors, reservoirs, and amplification hosts. The virus has been isolated in Africa in mosquitoes of the genera Aedes, Anopheles, and Mansonia, and in Southeast Asia and the Pacific area in mosquitoes of the genus Aedes. Aedes albopictus has invaded several countries in Central Africa and all Mediterranean countries, and continues to spread throughout Central and Northern Europe. The wide distribution of the virus in animal hosts and vectors favors the emergence of recombinants. The virus has been isolated in monkeys, and antibodies have been detected in domestic sheep, goats, horses, cows, ducks, rodents, bats, orangutans, and carabaos. It is a public health imperative to define the domestic and wild animal reservoirs, amplification hosts, and vector capacity of the genera Aedes, Anopheles, and Mansonia. These variables will define the geographic distribution of Zika virus along with the indicated timing and scale of the environmental public health interventions worldwide. Copyright © 2016 The Author. Published by Elsevier Ltd.. All rights reserved.

  12. Geographical distribution of the red howler monkey (Alouatta seniculus) and yellow fever in Colombia.

    Science.gov (United States)

    Piedrahita-Cortés, Juan; Soler-Tovar, Diego

    2016-02-11

    Colombia is a country with an important diversity of non-human primates, of which the red howler monkey (Alouatta seniculus) stands out because of its distribution and the role it plays in the occurrence of yellow fever.  To describe the geographic co-occurrence of Alouatta seniculus and the reported presence of yellow fever.  We conducted a descriptive study. The reported presence of yellow fever in Colombia was obtained from the reports and bulletins issued by the Instituto Nacional de Salud, and the study by Segura, et al. (2013). The occurrence of A. seniculus was determined based on the data from the Global Biodiversity Information Facility and the Colombian Biodiversity Information System. A map of the occurrence was developed using the DIVA-GIS program, and the ecological niche model under current conditions was created with the Maxent program.  The departments with the highest occurrence of A. seniculus were Antioquia, Meta and Casanare; 69.5% of the departments with reported history of yellow fever had co-occurrence with A. seniculus. The ecological niche model showed that Antioquia, Bolívar, La Guajira, Magdalena, Meta, Santander, Norte de Santander and Vichada had geographical portions with a probability rate nearing to 0.9 (90%).  In 69.5% of the departments with a history of yellow fever there was co-occurrence with A. seniculus, which is relevant because non-human primates play a well-known role as natural reservoirs of the virus, and they might contribute to the occurrence of the yellow fever, which makes them very useful as sentinels.

  13. An Analysis of the Geographic Distribution of Recently Graduated Dentists from the University of Western Australia: The World's Most Isolated Dental School

    Science.gov (United States)

    Gurbuxani, Amit; Kruger, Estie; Tennant, Marc

    2013-01-01

    Objective: The purpose of this study was to determine the geographic distribution of all new dentists who graduated over a period of six years. Perth, the capital city of Western Australia, is one of the world's most isolated cities, with a population of approximately 1.6 million people, situated over 2000km from its nearest next major capital…

  14. Temperature responses of some North Atlantic Cladophora species (Chlorophyceae) in relation to their geographic distribution

    Science.gov (United States)

    Cambridge, M.; Breeman, A. M.; van Oosterwijk, R.; van den Hoek, C.

    1984-09-01

    The temperature responses for growth and survival have been experimentally tested for 6 species of the green algal genus Cladophora (Chlorophyceae; Cladophorales) (all isolated from Roscoff, Brittany, France, one also from Connecticut, USA), selected from 4 distribution groups, in order to determine which phase in the annual temperature regime might prevent the spread of a species beyond its present latitudinal range on the N. Atlantic coasts. For five species geographic limits could be specifically defined as due to a growth limit in the growing season or to a lethal limit in the adverse season. These species were: (1) C. coelothrix (Amphiatlantic tropical to warm temperate), with a northern boundary on the European coasts formed by a summer growth limit near the 12°C August isotherm. On the American coasts sea temperatures should allow its occurrence further north. (2) C. vagabunda (Amphiatlantic tropical to temperate), with a northern boundary formed by a summer growth limit near the 15°C August isotherm on both sides of the Atlantic. (3) C. dalmatica, as for C. vagabunda. (4) C. hutchinsiae (Mediterranean-Atlantic warm temperate), with a northern boundary formed by a summer growth limit near the 12°C August isotherm, and possibly also a winter lethal limit near the 6°C February isotherm; and a southern boundary formed by a southern lethal limit near the 26°C August isotherm. It is absent from the warm temperate American coast because its lethal limits, 5° and 30°C, are regularly reached there. (5) Preliminary data for C. rupestris (Amphiatlantic temperate), suggest the southeastern boundary on the African coast to be a summer lethal limit near the 26°C August isotherm; the southwestern boundary on the American coast lies on the 20°C August isotherm. For one species, C. albida, the experimental growth and survival range was wider than expected from its geographic distribution, and reasons to account for this are suggested.

  15. Universally Primed-PCR indicates geographical variation of Peronospora farinosa ex. Chenopodium quinoa.

    Science.gov (United States)

    Danielsen, Solveig; Lübeck, Mette

    2010-02-01

    In the Andean region of South America downy mildew, caused by Peronospora farinosa, is the most important disease of quinoa (Chenopodium quinoa). Peronospora farinosa, a highly polyphyletic species, occurs on quinoa and wild relatives on all continents. However, very little is known about the geographic diversity of the pathogen. As the interest in quinoa as a novel crop is increasing worldwide, geographical differences in the population structure of the downy mildew pathogen must be taken into consideration in order to design appropriate control strategies under a variety of circumstances. As a step towards understanding the geographic diversity of P. farinosa from quinoa, 40 downy mildew isolates from the Andean highlands and Denmark were characterized using universally primed PCR (UP-PCR). Eight UP-PCR primers were tested. A combined analysis of markers separated the Danish and Andean isolates in two distinct clusters. This study raises new questions about the origin and spread of P. farinosa on quinoa, its geographic diversity and host specificity.

  16. Genetic diversity and geographic distribution of genetically distinct rabies viruses in the Philippines.

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    Mariko Saito

    Full Text Available BACKGROUND: Rabies continues to be a major public health problem in the Philippines, where 200-300 human cases were reported annually between 2001 and 2011. Understanding the phylogeography of rabies viruses is important for establishing a more effective and feasible control strategy. METHODS: We performed a molecular analysis of rabies viruses in the Philippines using rabied animal brain samples. The samples were collected from 11 of 17 regions, which covered three island groups (Luzon, Visayas, and Mindanao. Partial nucleoprotein (N gene sequencing was performed on 57 samples and complete glycoprotein (G gene sequencing was performed on 235 samples collected between 2004 and 2010. RESULTS: The Philippine strains of rabies viruses were included in a distinct phylogenetic cluster, previously named Asian 2b, which appeared to have diverged from the Chinese strain named Asian 2a. The Philippine strains were further divided into three major clades, which were found exclusively in different island groups: clades L, V, and M in Luzon, Visayas, and Mindanao, respectively. Clade L was subdivided into nine subclades (L1-L9 and clade V was subdivided into two subclades (V1 and V2. With a few exceptions, most strains in each subclade were distributed in specific geographic areas. There were also four strains that were divided into two genogroups but were not classified into any of the three major clades, and all four strains were found in the island group of Luzon. CONCLUSION: We detected three major clades and two distinct genogroups of rabies viruses in the Philippines. Our data suggest that viruses of each clade and subclade evolved independently in each area without frequent introduction into other areas. An important implication of these data is that geographically targeted dog vaccination using the island group approach may effectively control rabies in the Philippines.

  17. Using geographical semi-variogram method to quantify the difference between NO2 and PM2.5 spatial distribution characteristics in urban areas.

    Science.gov (United States)

    Song, Weize; Jia, Haifeng; Li, Zhilin; Tang, Deliang

    2018-08-01

    Urban air pollutant distribution is a concern in environmental and health studies. Particularly, the spatial distribution of NO 2 and PM 2.5 , which represent photochemical smog and haze pollution in urban areas, is of concern. This paper presents a study quantifying the seasonal differences between urban NO 2 and PM 2.5 distributions in Foshan, China. A geographical semi-variogram analysis was conducted to delineate the spatial variation in daily NO 2 and PM 2.5 concentrations. The data were collected from 38 sites in the government-operated monitoring network. The results showed that the total spatial variance of NO 2 is 38.5% higher than that of PM 2.5 . The random spatial variance of NO 2 was 1.6 times than that of PM 2.5 . The nugget effect (i.e., random to total spatial variance ratio) values of NO 2 and PM 2.5 were 29.7 and 20.9%, respectively. This indicates that urban NO 2 distribution was affected by both local and regional influencing factors, while urban PM 2.5 distribution was dominated by regional influencing factors. NO 2 had a larger seasonally averaged spatial autocorrelation distance (48km) than that of PM 2.5 (33km). The spatial range of NO 2 autocorrelation was larger in winter than the other seasons, and PM 2.5 has a smaller range of spatial autocorrelation in winter than the other seasons. Overall, the geographical semi-variogram analysis is a very effective method to enrich the understanding of NO 2 and PM 2.5 distributions. It can provide scientific evidences for the buffering radius selection of spatial predictors for land use regression models. It will also be beneficial for developing the targeted policies and measures to reduce NO 2 and PM 2.5 pollution levels. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Pathogenic landscapes: Interactions between land, people, disease vectors, and their animal hosts

    Science.gov (United States)

    2010-01-01

    Background Landscape attributes influence spatial variations in disease risk or incidence. We present a review of the key findings from eight case studies that we conducted in Europe and West Africa on the impact of land changes on emerging or re-emerging vector-borne diseases and/or zoonoses. The case studies concern West Nile virus transmission in Senegal, tick-borne encephalitis incidence in Latvia, sandfly abundance in the French Pyrenees, Rift Valley Fever in the Ferlo (Senegal), West Nile Fever and the risk of malaria re-emergence in the Camargue, and rodent-borne Puumala hantavirus and Lyme borreliosis in Belgium. Results We identified general principles governing landscape epidemiology in these diverse disease systems and geographic regions. We formulated ten propositions that are related to landscape attributes, spatial patterns and habitat connectivity, pathways of pathogen transmission between vectors and hosts, scale issues, land use and ownership, and human behaviour associated with transmission cycles. Conclusions A static view of the "pathogenecity" of landscapes overlays maps of the spatial distribution of vectors and their habitats, animal hosts carrying specific pathogens and their habitat, and susceptible human hosts and their land use. A more dynamic view emphasizing the spatial and temporal interactions between these agents at multiple scales is more appropriate. We also highlight the complementarity of the modelling approaches used in our case studies. Integrated analyses at the landscape scale allows a better understanding of interactions between changes in ecosystems and climate, land use and human behaviour, and the ecology of vectors and animal hosts of infectious agents. PMID:20979609

  19. New data on the ecology and geographic distribution of Saguinus inustus Schwarz, 1951 (Primates, Callitrichidae

    Directory of Open Access Journals (Sweden)

    J. Valsecchi

    Full Text Available Saguinus inustus (Schwarz, 1951 is one of the neotropical primates least studied. The distribution of the species ranges from the north of the Solimões River, between the Negro and Japurá Rivers in Brazil, and Guayabero-Guaviare Rivers in Colombia. Nevertheless, due to the low number of specimens collected from the lower Japurá and lower Negro Rivers areas, the geographic distribution is so far poorly delineated. In this study, field data was composed of sightings and the collection of specimens during a survey of mammal diversity in the Amana Sustainable Development Reserve (ASDR. For this survey, two 40-day expeditions were carried out in 2004. The first one occurred during the flooded season in June and July, and the second was during the peak of the dry season in October. Direct sightings were made through hiking along transects, navigation along water channels with a 30-hp speedboat, and gliding along flooded trails in the forest. New records of S. inustus were made in 11 different localities in ASDR. The study has confirmed the presence of the species in the Amanã area, carrying out the first records of the species in flooded forest habitats.

  20. Host specificity and geographical distribution of Eubothrium in European salmonid fish

    Czech Academy of Sciences Publication Activity Database

    Scholz, Tomáš; Kuchta, Roman; Shinn, A. P.; Šnábel, V.; Hanzelová, V.

    2003-01-01

    Roč. 77, č. 3 (2003), s. 255-262 ISSN 0022-149X R&D Projects: GA ČR GA524/01/1314 Grant - others:Vedecká grantová agentúra MŠ SR a SAV(SK) VEGA2/1020/21 Institutional research plan: CEZ:AV0Z6022909 Keywords : Cestoda * Pseudophyllidea * fish parasites Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 0.939, year: 2003

  1. Methylmercury in fish from the South China Sea: geographical distribution and biomagnification.

    Science.gov (United States)

    Zhu, Aijia; Zhang, Wei; Xu, Zhanzhou; Huang, Liangmin; Wang, Wen-Xiong

    2013-12-15

    We conducted a large-scale investigation of methylmercury (MeHg) in a total of 628 marine wild fish covering 46 different species collected from the South China Sea between 2008 and 2009. Biological and ecological characteristics such as size (length and wet weight), feeding habit, habitat, and stable isotope (δ(15)N) were examined to explain MeHg bioaccumulation in marine fish and their geographical distribution. MeHg levels in the muscle tissues of the 628 individuals ranged from 0.010 to 1.811 μg/g dry wt. Log10MeHg concentration was significantly related to their length and wet weight. Feeding habit and habitat were the primary factors influencing MeHg bioaccumulation. Demersal fish were more likely to be contaminated with MeHg than the epipelagic and mesopelagic varieties. Linear relationships were obtained between Log10(MeHg) and δ(15)N only for one location, indicating that biomagnification was site-specific. Results from this study suggest that dietary preference and trophic structure were the main factors affecting MeHg bioaccumulation in marine fish from the South China Sea. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. The South-American distribution and southernmost record of Biomphalaria peregrina—a potential intermediate host of schistosomiasis

    Directory of Open Access Journals (Sweden)

    Alejandra Rumi

    2017-05-01

    Full Text Available Schistosomiasis remains a major parasitic disease, endemic in large parts of South America. Five neotropical species of Biomphalaria have been found to act as intermediate hosts of Schistosoma mansoni in natural populations, while others have been shown to be susceptible in experimental infections, although not found infected in the field. Among these potential intermediate hosts, Biomphalaria peregrina represents the most widespread species in South America, with confirmed occurrence records from Venezuela to northern Patagonia. In this study, we report the southernmost record for the species at the Pinturas River, in southern Patagonia, which finding implies a southward reassessment of the limit for the known species of this genus. The identities of the individuals from this population were confirmed through morphological examination, and by means of two mitochondrial genes, cytochrome oxidase subunit I (COI and 16S-rRNA. With both markers, phylogenetic analyses were conducted in order to compare the genetic background of individuals from the Pinturas River with previously genetically characterized strains of B. peregrina from various South-American locations. In addition, we produced a potential distribution model of B. peregrina in South America and identified the environmental variables that best predict that distribution. The model was estimated through a maximum entropy algorithm and run with occurrence points obtained from several sources, including the scientific literature and international databases, along with climatic and hydrographic variables. Different phylogenetic analyses with either the COI or 16S-rRNA sequences did not conflict, but rather gave very similar topological organizations. Two major groups were identified, with sequences from the Pinturas River grouping together with haplotypes from subtropical and temperate regions. The model developed had a satisfactory performance for the study area. We observed that the areas

  3. Nestedness in assemblages of helminth parasites of bats: a function of geography, environment, or host nestedness?

    Science.gov (United States)

    Warburton, Elizabeth M; Van Der Mescht, Luther; Khokhlova, Irina S; Krasnov, Boris R; Vonhof, Maarten J

    2018-05-01

    Nested subsets occur in ecological communities when species-poor communities are subsets of larger, species-rich communities. Understanding this pattern can help elucidate species colonization abilities, extinction risks, and general structuring of biological communities. Here, we evaluate nestedness in a poorly studied host-parasite system, bats and their helminths, across the Japanese archipelago and within its different bioclimatic regions. We hypothesized that (1) if helminth communities are nested across geographic sites at the level of the archipelago, then broad-scale processes, like colonization-extinction dynamics, mainly structure parasite assemblages; (2) if helminth communities are nested across geographic sites at the level of the bioclimatic region, then fine-scale environmental variation plays a significant role in species nestedness; (3) if helminth community nestedness mirrors host species nestedness, then communities are nested because the habitats they occupy are nested; and (4) if nestedness does not occur or if it is not correlated with any geographical or host data, then passive sampling could be responsible for the patterns of parasite assemblage in our sample. We found that helminth communities were nested across host species throughout the archipelago but, when considering each bioclimatic region, helminths in only one region were significantly more nested than the null model. Helminth communities were also nested across sites within all four bioclimatic regions. These results suggest that helminths form nested subsets across the archipelago due to broad-scale processes that reflect the overall lineages of their mammalian hosts; however, at the regional scale, environmental processes related to nestedness of their habitats drive parasite community nestedness.

  4. Geographic distribution and spatial differentiation in the color pattern of abdominal stripes of the Neotropical stingless bee Melipona quadrifasciata (Hymenoptera: Apidae

    Directory of Open Access Journals (Sweden)

    Henrique Batalha-Filho

    2009-06-01

    Full Text Available Melipona quadrifasciata Lepeletier, 1836, regionally known as "mandaçaia", has been traditionally divided in two distinct subspecies: M. quadrifasciata anthidioides and M. quadrifasciata quadrifasciata. The main difference between the subspecies refers to the yellow metasomal stripes which are continuous in M. q. quadrifasciata and discontinuous in M. q. anthidioides. This study investigated the geographic differentiation in the metasomal stripes and characterized the restriction sites in the mtDNA of both chromatic types. Specimens from 198 localities were examined, and the variation observed in the pattern of stripes was grouped into distinct classes. The distribution pattern found in the present work agrees with the previously reported pattern: M. q. quadrifasciata inhabits the southern portion of the distribution, from Misiones, Argentina, southeastern Paraguay and Rio Grande do Sul to southern São Paulo, and M. q. anthidioides ranges from northeastern São Paulo to the northern Diamantina Plateau, Bahia, and westwards to the central portion of the Goiás state. It is documented for the first time the occurrence of two populations with continuous stripes inhabiting disjunct areas in relation to M. q. quadrifasciata - one in northern Minas Gerais and another in northeastern Bahia and Sergipe. The data of RFLP showed two restriction patterns, one present in M. q. quadrifasciata, and another in M. q. anthidioides and in populations with continuous metasomal stripes from northern Minas Gerais and northeastern Bahia and Sergipe. The observed patterns of geographic differentiation of M. quadrifasciata suggests the occurrence of repeated events of geographical isolation, followed by range expansion, that occurred probably during the cycles of climatic changes in the Pleistocene.

  5. Population genetic structure of a common host predicts the spread of white-nose syndrome, an emerging infectious disease in bats.

    Science.gov (United States)

    Wilder, Aryn P; Kunz, Thomas H; Sorenson, Michael D

    2015-11-01

    Landscape complexity influences patterns of animal dispersal, which in turn may affect both gene flow and the spread of pathogens. White-nose syndrome (WNS) is an introduced fungal disease that has spread rapidly throughout eastern North America, causing massive mortality in bat populations. We tested for a relationship between the population genetic structure of the most common host, the little brown myotis (Myotis lucifugus), and the geographic spread of WNS to date by evaluating logistic regression models of WNS risk among hibernating colonies in eastern North America. We hypothesized that risk of WNS to susceptible host colonies should increase with both geographic proximity and genetic similarity, reflecting historical connectivity, to infected colonies. Consistent with this hypothesis, inclusion of genetic distance between infected and susceptible colonies significantly improved models of disease spread, capturing heterogeneity in the spatial expansion of WNS despite low levels of genetic differentiation among eastern populations. Expanding our genetic analysis to the continental range of little brown myotis reveals strongly contrasting patterns of population structure between eastern and western North America. Genetic structure increases markedly moving westward into the northern Great Plains, beyond the current distribution of WNS. In western North America, genetic differentiation of geographically proximate populations often exceeds levels observed across the entire eastern region, suggesting infrequent and/or locally restricted dispersal, and thus relatively limited opportunities for pathogen introduction in western North America. Taken together, our analyses suggest a possibly slower future rate of spread of the WNS pathogen, at least as mediated by little brown myotis. © 2015 John Wiley & Sons Ltd.

  6. POTENTIAL DISTRIBUTION OF ORANGE JASMINE (Murraya paniculata IN MEXICO

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    José López-Collado

    2013-04-01

    Full Text Available Orange jasmine (OJ is a common ornamental plant used as green hedge in public and private gardens in Mexico. It also hosts Huanglongbing, a worldwide citrus disease and its vector, Diaphorina citri. For risk analysis and management purpose is important to know its geographic distribution. The potential distribution of OJ was calculated in Mexico using a deductive approach. Based on temperature and precipitation requirements, a relative suitability index was computed by combining the normalized values of both variables. The distribution was overlapped with captures of D. citri to check their spatial similarity. The results showed that the potential of occurrence is high in the Pacific and Gulf of México coastal states, including the Yucatán peninsula, and the lowest values appeared in the north-western states. The OJ distribution overlaps with Huanglongbing occurrence and coincided with captures of D. citri for most of the suitable area but D. citri captures extended beyond the optimal OJ distribution values in the northern regions of México.

  7. Potential geographic distribution and conservation of Audubon's Shearwater, Puffinus lherminieri in Brazil

    Directory of Open Access Journals (Sweden)

    Ana Cecília P.A. Lopes

    2014-01-01

    Full Text Available Audubon's Shearwater (Puffinus lherminieri Lesson 1839 is a tropical seabird occurring mainly between southern Canada and the southeast coast of Brazil. Puffinus lherminieri is considered Critically Endangered on the Brazilian Red List because it only occurs in two known localities, both of which contain very small populations. However, many offshore islands along the Brazilian coast are poorly known and the discovery of new colonies would be of considerable significance for the conservation of this species. The aim of this study was to estimate the potential geographic distribution of Audubon's Shearwater in Brazil, based on ecological niche model (ENM using Maxent algorithm with layers obtained from AquaMaps environmental dataset. The ENM was based on 37 records for reproduction areas in North and South America. The model yielded a very broad potential distribution, covering most of the Atlantic coast ranging from Brazil to the US. When filtered for islands along the Brazilian coast, the model indicates higher levels of environmental suitability near the states of São Paulo, Rio de Janeiro, Espírito Santo and Bahia. However, P. lherminieri prefers islands in environments with warm saline water. Thus, based on the influence of currents that act on the Brazilian coast we can infer undiscovered colonies are most likely to occur on islands on coast of Bahia, Espírito Santo and extreme north of the Rio de Janeiro. These should be intensively surveyed while the islands south of Cabo Frio should be discarded. The existence of new populations would have profound effects on the conservation status of this enigmatic and rarely seen seabird.

  8. Biology and occurrence of Inga Busk species (Lepidoptera: Oecophoridae) on Cerrado host plants.

    Science.gov (United States)

    Diniz, Ivone R; Bernardes, Carolina; Rodovalho, Sheila; Morais, Helena C

    2007-01-01

    We sampled Inga Busk species caterpillars weekly in the cerrado on 15 plants of Diospyros burchellii Hern. (Ebenaceae) from January 2002 to December 2003, on 30 plants of Caryocar brasiliense (Caryocaraceae) from July 2003 to June 2004, and since 1991 on several other plant species. In total we found 15 species of Inga on cerrado host plants. Nine species were very rare, with only one to five adults reared. The other six species occurred throughout the year, with higher abundance during the dry season, from May to July, coinciding with overall peaks of caterpillar abundance in the cerrado. Caterpillars of the genus Inga build shelters by tying and lining two mature or old leaves with silk and frass, where they rest and develop (a common habit found in Oecophorinae). The final instar builds a special envelope inside the leaf shelter, where it will complete the larval stage and pupate. The species are very difficult to distinguish in the immature stages. External features were useful in identifying only four species: I. haemataula (Meyrick), I. phaecrossa (Meyrick), I. ancorata (Walsingham), and I. corystes (Meyrick). These four species are polyphagous and have wide geographical distributions. In this paper we provide information on the natural history and host plants of six Inga species common on cerrado host plants, for which there are no reports in the literature.

  9. Alloxenic distribution of cystacanths of two Profilicollis species in sympatric crustacean hosts in Chile.

    Science.gov (United States)

    Balboa, L; Hinojosa, A; Riquelme, C; Rodríguez, S; Bustos, J; George-Nascimento, M

    2009-10-01

    The taxonomic status of Profilicollis ( = Falsifilicollis Webster, 1948) species in crustaceans in Chile is examined. Mole crabs, Emerita analoga (Stimpson 1857), living in the splash zone of a sandy beach at Lenga off the coast of central Chile, harbor Polymorphus (Profilicollis) bullocki Mateo, Córdova and Guzmán 1982, while the estuarine crabs, Hemigrapsus crenulatus (Milne-Edwards, 1837), living in an oligohaline inlet at the same site, harbor Profilicollis spp. cystacanths which cannot be distinguished specifically to either Profilicollis antarcticus or P. chasmagnathi Holcman-Spector, Mañé-Garzón and Dei-Cas 1977. We found no morphological data supporting records of P. altmani along the coast of Chile. Therefore, and after examination of both their morphology and the literature, we consider that P. bullocki must be reinstated as a valid species in the genus. There is a widespread distribution of habitats, such as sandy beaches and inlets, as well as a variety of host taxa involved in the life cycle of Profilicollis spp. Consequently, they provide an interesting scenario for testing hypotheses regarding the coevolution and host specificity of these parasites.

  10. Effects of geographical extent on the determinants of woody plant diversity

    DEFF Research Database (Denmark)

    Wang, Zhiheng; Rahbek, Carsten; Fang, Jingyun

    2012-01-01

    the quantitative effects of geographical extent are rarely tested. Here, using distribution maps of 11,405 woody species found in China and associated environmental data to the domain, we investigated the influence of geographical extent on the determinants of species richness patterns. Our results revealed...

  11. Temporal trend, geographic distribution, and publication quality in asbestos research.

    Science.gov (United States)

    Ugolini, Donatella; Bonassi, Stefano; Cristaudo, Alfonso; Leoncini, Giacomo; Ratto, Giovanni Battista; Neri, Monica

    2015-05-01

    Asbestos is a well-known cause of cancer and respiratory diseases. The aim of the current study was to investigate the scientific production in asbestos research evaluating temporal trend, geographic distribution, impact factor (IF) of published literature, and taking into account socioeconomic variables. The PubMed database was searched starting from 1970. Publication numbers and IF were evaluated as absolute values and after standardization by population and gross domestic product (GDP). Six thousand nine hundred seven articles related to asbestos were retrieved. Publications grew steeply in the 1970s, leveled off in the 1980s, decreased in the 1990s, and then increased again. Mesothelioma, lung neoplasms, and occupational diseases are the most commonly used keywords. In the period of 1988-2011, 4220 citations were retrieved, 3187 of whom had an impact factor. The US, Italy, and the UK were the most productive countries. European countries published about 20 % more asbestos-related articles than the US, although the latter reached a higher mean IF, ranking second after Australia. When the national scientific production (sum of IF) was compared taking into account socioeconomic variables, Australia and Scandinavian countries performed very well, opposite to all main asbestos producers like Russia, China, and Brazil (except for Canada). The American Journal of Industrial Medicine and the Italian La Medicina del Lavoro published the highest numbers of articles. This study provides the first bibliometric analysis of scientific production in asbestos research. Interest appears to be higher in selected countries, with strong national features, and is growing again in the new millennium.

  12. The roles of geography and founder effects in promoting host-associated differentiation in the generalist bogus yucca moth Prodoxus decipiens.

    Science.gov (United States)

    Darwell, C T; Fox, K A; Althoff, D M

    2014-12-01

    There is ample evidence that host shifts in plant-feeding insects have been instrumental in generating the enormous diversity of insects. Changes in host use can cause host-associated differentiation (HAD) among populations that may lead to reproductive isolation and eventual speciation. The importance of geography in facilitating this process remains controversial. We examined the geographic context of HAD in the wide-ranging generalist yucca moth Prodoxus decipiens. Previous work demonstrated HAD among sympatric moth populations feeding on two different Yucca species occurring on the barrier islands of North Carolina, USA. We assessed the genetic structure of P. decipiens across its entire geographic and host range to determine whether HAD is widespread in this generalist herbivore. Population genetic analyses of microsatellite and mtDNA sequence data across the entire range showed genetic structuring with respect to host use and geography. In particular, genetic differentiation was relatively strong between mainland populations and those on the barrier islands of North Carolina. Finer scale analyses, however, among sympatric populations using different host plant species only showed significant clustering based on host use for populations on the barrier islands. Mainland populations did not form population clusters based on host plant use. Reduced genetic diversity in the barrier island populations, especially on the derived host, suggests that founder effects may have been instrumental in facilitating HAD. In general, results suggest that the interplay of local adaptation, geography and demography can determine the tempo of HAD. We argue that future studies should include comprehensive surveys across a wide range of environmental and geographic conditions to elucidate the contribution of various processes to HAD. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  13. Hosting Capacity of Solar Photovoltaics in Distribution Grids under Different Pricing Schemes

    DEFF Research Database (Denmark)

    Carollo, Riccardo; Chaudhary, Sanjay Kumar; Pillai, Jayakrishnan Radhakrishna

    2015-01-01

    Most of the solar photovoltaic (SPV) installations are connected to distribution networks. The majority of these systems are represented by single-phase rooftop SPVs connected to residential low voltage (LV) grids. The large SPV shares lead to grid integration issues such as voltage rise....... The results show that with the present TOU tariffs the EV integration in LV networks does not ease the grid bottlenecks for large PV penetration. Under the Net metering and DLMP the EV integration in LV grids tend to increase the PV hosting capacity......., overloading of the network components, voltage phase unbalance etc. A rapid expansion of Electric Vehicles (EVs) technology is estimated, whose connection is also expected to take place in the LV networks. EVs might represent a possible solution to the SPV integration issues as they can be used as fast...

  14. THE SWIFT GRB HOST GALAXY LEGACY SURVEY. II. REST-FRAME NEAR-IR LUMINOSITY DISTRIBUTION AND EVIDENCE FOR A NEAR-SOLAR METALLICITY THRESHOLD

    Energy Technology Data Exchange (ETDEWEB)

    Perley, D. A. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Blvd., Pasadena, CA 91125 (United States); Tanvir, N. R. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Hjorth, J.; Fynbo, J. P. U.; Krühler, T. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 København Ø (Denmark); Laskar, T.; Berger, E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Chary, R. [US Planck Data Center, MS220-6, Pasadena, CA 91125 (United States); Postigo, A. de Ugarte [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, E-18008, Granada (Spain); Levan, A. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Michałowski, M. J. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Schulze, S., E-mail: dperley@dark-cosmology.dk [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, 7820436 Macul, Santiago 22 (Chile)

    2016-01-20

    We present rest-frame near-IR (NIR) luminosities and stellar masses for a large and uniformly selected population of gamma-ray burst (GRB) host galaxies using deep Spitzer Space Telescope imaging of 119 targets from the Swift GRB Host Galaxy Legacy Survey spanning 0.03 < z < 6.3, and we determine the effects of galaxy evolution and chemical enrichment on the mass distribution of the GRB host population across cosmic history. We find a rapid increase in the characteristic NIR host luminosity between z ∼ 0.5 and z ∼ 1.5, but little variation between z ∼ 1.5 and z ∼ 5. Dust-obscured GRBs dominate the massive host population but are only rarely seen associated with low-mass hosts, indicating that massive star-forming galaxies are universally and (to some extent) homogeneously dusty at high redshift while low-mass star-forming galaxies retain little dust in their interstellar medium. Comparing our luminosity distributions with field surveys and measurements of the high-z mass–metallicity relation, our results have good consistency with a model in which the GRB rate per unit star formation is constant in galaxies with gas-phase metallicity below approximately the solar value but heavily suppressed in more metal-rich environments. This model also naturally explains the previously reported “excess” in the GRB rate beyond z ≳ 2; metals stifle GRB production in most galaxies at z < 1.5 but have only minor impact at higher redshifts. The metallicity threshold we infer is much higher than predicted by single-star models and favors a binary progenitor. Our observations also constrain the fraction of cosmic star formation in low-mass galaxies undetectable to Spitzer to be small at z < 4.

  15. Hierarchical Distributed-Lag Models: Exploring Varying Geographic Scale and Magnitude in Associations Between the Built Environment and Health.

    Science.gov (United States)

    Baek, Jonggyu; Sanchez-Vaznaugh, Emma V; Sánchez, Brisa N

    2016-03-15

    It is well known that associations between features of the built environment and health depend on the geographic scale used to construct environmental attributes. In the built environment literature, it has long been argued that geographic scales may vary across study locations. However, this hypothesized variation has not been systematically examined due to a lack of available statistical methods. We propose a hierarchical distributed-lag model (HDLM) for estimating the underlying overall shape of food environment-health associations as a function of distance from locations of interest. This method enables indirect assessment of relevant geographic scales and captures area-level heterogeneity in the magnitudes of associations, along with relevant distances within areas. The proposed model was used to systematically examine area-level variation in the association between availability of convenience stores around schools and children's weights. For this case study, body mass index (weight kg)/height (m)2) z scores (BMIz) for 7th grade children collected via California's 2001-2009 FitnessGram testing program were linked to a commercial database that contained locations of food outlets statewide. Findings suggested that convenience store availability may influence BMIz only in some places and at varying distances from schools. Future research should examine localized environmental or policy differences that may explain the heterogeneity in convenience store-BMIz associations. © The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. The distribution and habitat preferences of the declining species Orobanche arenaria Borkh at the northern limit of its geographical range

    Directory of Open Access Journals (Sweden)

    Renata Piwowarczyk

    2011-01-01

    Full Text Available Three new sites of Orobanche arenaria were discovered during floristic investigations in the Wyżyna Małopolska upland in central Poland. The new localities are concentrated in the Ponidzie area (Garb Pińczowski ridge and Niecka Połaniecka basin and form the northern limit of the geographical range of O. arenaria. The paper presents information on the distribution of Orobanche arenaria in Poland, the abundance at the sites and habitats occupied by the species.

  17. Simulated effects of host fish distribution on juvenile unionid mussel dispersal in a large river

    Science.gov (United States)

    Daraio, J.A.; Weber, L.J.; Zigler, S.J.; Newton, T.J.; Nestler, J.M.

    2012-01-01

    Larval mussels (Family Unionidae) are obligate parasites on fish, and after excystment from their host, as juveniles, they are transported with flow. We know relatively little about the mechanisms that affect dispersal and subsequent settlement of juvenile mussels in large rivers. We used a three-dimensional hydrodynamic model of a reach of the Upper Mississippi River with stochastic Lagrangian particle tracking to simulate juvenile dispersal. Sensitivity analyses were used to determine the importance of excystment location in two-dimensional space (lateral and longitudinal) and to assess the effects of vertical location (depth in the water column) on dispersal distances and juvenile settling distributions. In our simulations, greater than 50% of juveniles mussels settled on the river bottom within 500 m of their point of excystment, regardless of the vertical location of the fish in the water column. Dispersal distances were most variable in environments with higher velocity and high gradients in velocity, such as along channel margins, near the channel bed, or where effects of river bed morphology caused large changes in hydraulics. Dispersal distance was greater and variance was greater when juvenile excystment occurred in areas where vertical velocity (w) was positive (indicating an upward velocity) than when w was negative. Juvenile dispersal distance is likely to be more variable for mussels species whose hosts inhabit areas with steeper velocity gradients (e.g. channel margins) than a host that generally inhabits low-flow environments (e.g. impounded areas).

  18. Geographic patterns and environmental factors associated with human yellow fever presence in the Americas.

    Science.gov (United States)

    Hamrick, Patricia Najera; Aldighieri, Sylvain; Machado, Gustavo; Leonel, Deise Galan; Vilca, Luz Maria; Uriona, Sonia; Schneider, Maria Cristina

    2017-09-01

    In the Americas, yellow fever virus transmission is a latent threat due to the proximity between urban and wild environments. Although yellow fever has nearly vanished from North and Central America, there are still 13 countries in the Americas considered endemic by the World Health Organization. Human cases usually occur as a result of the exposure to sylvatic yellow fever in tropical forested environments; but urban outbreaks reported during the last decade demonstrate that the risk in this environment still exists. The objective of this study was to identify spatial patterns and the relationship between key geographic and environmental factors with the distribution of yellow fever human cases in the Americas. An ecological study was carried out to analyze yellow fever human cases reported to the Pan American Health Organization from 2000 to 2014, aggregated by second administrative level subdivisions (counties). Presence of yellow fever by county was used as the outcome variable and eight geo-environmental factors were used as independent variables. Spatial analysis was performed to identify and examine natural settings per county. Subsequently, a multivariable logistic regression model was built. During the study period, 1,164 cases were reported in eight out of the 13 endemic countries. Nearly 83.8% of these cases were concentrated in three countries: Peru (37.4%), Brazil (28.1%) and Colombia (18.4%); and distributed in 57 states/provinces, specifically in 286 counties (3.4% of total counties). Yellow fever presence was significantly associated with altitude, rain, diversity of non-human primate hosts and temperature. A positive spatial autocorrelation revealed a clustered geographic pattern in 138/286 yellow fever positive counties (48.3%). A clustered geographic pattern of yellow fever was identified mostly along the Andes eastern foothills. This risk map could support health policies in endemic countries. Geo-environmental factors associated with presence

  19. Unravelling the role of host plant expansion in the diversification of a Neotropical butterfly genus.

    Science.gov (United States)

    McClure, Melanie; Elias, Marianne

    2016-06-16

    Understanding the processes underlying diversification is a central question in evolutionary biology. For butterflies, access to new host plants provides opportunities for adaptive speciation. On the one hand, locally abundant host species can generate ecologically significant selection pressure. But a diversity of host plant species within the geographic range of each population and/or species might also eliminate any advantage conferred by specialization. This paper focuses on four Melinaea species, which are oligophagous on the family Solanaceae: M. menophilus, M. satevis, M. marsaeus, and finally, M. mothone. We examined both female preference and larval performance on two host plant species that commonly occur in this butterfly's native range, Juanulloa parasitica and Trianaea speciosa, to determine whether the different Melinaea species show evidence of local adaptation. In choice experiments, M. mothone females used both host plants for oviposition, whereas all other species used J. parasitica almost exclusively. In no choice experiment, M. mothone was the only species that readily accepted T. speciosa as a larval host plant. Larval survival was highest on J. parasitica (82.0 % vs. 60.9 %) and development took longer on T. speciosa (14.12 days vs. 13.35 days), except for M. mothone, which did equally well on both host plants. For all species, average pupal weight was highest on J. parasitica (450.66 mg vs. 420.01 mg), although this difference was least apparent in M. mothone. We did not find that coexisting species of Melinaea partition host plant resources as expected if speciation is primarily driven by host plant divergence. Although M. mothone shows evidence of local adaptation to a novel host plant, T. speciosa, which co-occurs, it does not preferentially lay more eggs on or perform better on this host plant than on host plants used by other Melinaea species and not present in its distributional range. It is likely that diversification in this

  20. Geographic distribution of the tortoises and freshwater turtles of Colombia and their representation in the protected area network

    International Nuclear Information System (INIS)

    Forero Medina, German; Yusti Munoz, Ana Paola; Castano Mora, Olga V

    2014-01-01

    Colombia has a remarkable diversity of tortoises and freshwater turtles. However, a considerable portion of these species is threatened, and for others there is not enough information to make an adequate evaluation of their conservation status. This study is a first approximation to the quantitative evaluation of the geographic distribution of Colombia's non-marine chelonians. Based on records of occurrence for each species, we evaluated the geographic distribution using statistical models (maxent), hydrological basins, and the extent of occurrence and area of occupancy. Based on the presence data and the models, we studied the representation of each species in national natural parks (NNP), which correspond to the most rigorous conservation category of IUCN classification in Colombia, and other types of protected areas such as private reserves. We generated distribution models and estimated the area (km"2) for 25 out of 27 species in the country. This information will be valuable for updating and evaluating the threat categories at the national level. The areas with the highest species richness correspond to the riverine ecosystems of the Amazon and Orinoco River Basins and the Caribbean Region, particularly the Western Caribbean. This region is a top priority not only because of its richness but also because of the presence of endemics and its high level of threat. Only 56 % of the species have confirmed records within national parks. A greater portion could be present in these areas according to the statistical models, but only ten of those species would have more than 10 % of their ranges within a park's boundary. Although the resulting models have certain limitations due to the nature of the data and analyses, they can be a starting point for research on the occurrence of turtles in NNP. Endemic species are poorly represented in protected areas, both in NNP and in other categories. Thus, protected areas that can assure the persistence of their populations are

  1. LIFE CYCLE, DISTRIBUTION AND ABUNDANCE OF CARCINONEMERTES EPIALTI, A NEMERTEAN EGG PREDATOR OF THE SHORE CRAB, HEMIGRAPSUS OREGONENSIS, IN RELATION TO HOST SIZE, REPRODUCTION AND MOLT CYCLE.

    Science.gov (United States)

    Kuris, Armand M

    1978-02-01

    1. The geographic range of Carcinonemertes epialti has been greatly extended. The worms are found from Bahia San Quintin, Baja California, Mexico, to Page's Lagoon, Vancouver Island, British Columbia, Canada. 2. New host records for C. epialti include H. oregonensis, and H. nudus. It is rare on its type host Pugettia producta. Specimens of Carcinonemertes of uncertain affinities are also found on Cancer antennarius, C. anthonyi and C. productus. 3. Carcinonemertes epialti adults are egg predators on ovigerous hosts. Growth, demography and abundance are described in relation to the embryogenic stage of the host brood at Bodega Harbor, California. 4. Nonfeeding juveniles are ensheathed on individuals of both host sexes over 8.0 mm carapace width. 5. Transmission experiments show that contact transfer of juvenile nemerteans from males to other hosts may occur. 6. The percentage of infestation and mean density peak in autumn on H. oregonensis at Bodega Harbor. 7. Ovigerous female hosts are more frequently infested with C. epialti, particularly at small host sizes, than are male or nonovigerous female hosts at Bodega Harbor. However, average worm density on ovigerous females is low. 8. Mean density of C. epialti rises through late postmolt, declines during intermolt and rebuilds to a high level in late premolt H. oregonensisfrom Bodega Harbor. 9. Large crabs have a higher percentage of infestations and mean densities per infection than do small crabs. Nemerteans are more frequently found in the sternal-abdominal furrow and less frequently in the limb axillae on large crabs. 10. A model of C. epialti transmission and site occupancy is proposed, incorporating the influence of host size, sex, reproductive state, embryogenesis, molt cycle stage and molt cycle duration of H. oregonensis at Bodega Harbor. Site availability increases with host size. At higher densities the juvenile nemerteans increasingly occupy less preferred sites. Transferral of juvenile nemerteans occurs

  2. [Temporal variation and geographical distribution: congenital heart defects in the Comunitat Valenciana].

    Science.gov (United States)

    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.

  3. Sediment-hosted contaminants and distribution patterns in the Mississippi and Atchafalaya River Deltas

    Science.gov (United States)

    Flocks, James G.; Kindinger, Jack G.; Ferina, Nicholas; Dreher, Chandra

    2002-01-01

    The Mississippi and Atchafalaya Rivers transport very large amounts of bedload and suspended sediments to the deltaic and coastal environments of the northern Gulf of Mexico. Absorbed onto these sediments are contaminants that may be detrimental to the environment. To adequately assess the impact of these contaminants it is first necessary to develop an understanding of sediment distribution patterns in these deltaic systems. The distribution patterns are defined by deltaic progradational cycles. Once these patterns are identified, the natural and industrial contaminant inventories and their depositional histories can be reconstructed. Delta progradation is a function of sediment discharge, as well as channel and receiving-basin dimensions. Fluvial energy controls the sediment distribution pattern, resulting in a coarse grained or sandy framework, infilled with finer grained material occupying the overbank, interdistributary bays, wetlands and abandoned channels. It has been shown that these fine-grained sediments can carry contaminants through absorption and intern them in the sediment column or redistribute them depending on progradation or degradation of the delta deposit. Sediment distribution patterns in delta complexes can be determined through high-resolution geophysical surveys and groundtruthed with direct sampling. In the Atchafalaya and Mississippi deltas, remote sensing using High-Resolution Single-Channel Seismic Profiling (HRSP) and Sidescan Sonar was correlated to 20-ft vibracores to develop a near-surface geologic framework that identifies variability in recent sediment distribution patterns. The surveys identified bedload sand waves, abandoned-channel back-fill, prodelta and distributary mouth bars within the most recently active portions of the deltas. These depositional features respond to changes in deltaic processes and through their response may intern or transport absorbed contaminants. Characterizing these features provides insight into the

  4. Lumbricidae as transitory hosts in Metastrongylus infection in swine

    Directory of Open Access Journals (Sweden)

    Pavlović Ivan

    2005-01-01

    Full Text Available Metastrongylidosis or lungworm disease in swine is a disease caused by several types of nematodes of the genus Metastrongylus. Metastrongylidae are biohelminths whose causes use transitory hosts for their development and maintaining their biological cycle, and in this case they are numerous species of Lumbricidae (earthworms. Depending on the geographic environment, numerous representatives of Lumbricidae persist as transitory hosts. In our environment, these are dominant earthworm species of the genus Eisenia spp, Dandreobena spp, Allopbophora spp, Lubricus spp, Octoiasium spp, Bimastus spp, and rarely those from the genus Heledrillus spp. Swine are infected perorally with Metastrongylidae when they ingest infected earthworms.

  5. Correlation of geographic distributions of haptoglobin alleles with prevalence of multiple sclerosis (MS) - a narrative literature review.

    Science.gov (United States)

    Bamm, Vladimir V; Geist, Arielle M; Harauz, George

    2017-02-01

    We have proposed that the myelin damage observed in multiple sclerosis (MS) may be partly mediated through the long-term release and degradation of extracellular hemoglobin (Hb) and the products of its oxidative degradation [Cellular and Molecular Life Sciences, 71, 1789-1798, 2014]. The protein haptoglobin (Hpt) binds extracellular Hb as a first line of defense, and can serve as a vascular antioxidant. Humans have two different Hpt alleles: Hpt1 and Hpt2, giving either homozygous Hpt1-1 or Hpt2-2 phenotypes, or a heterozygous Hpt1-2 phenotype. We questioned whether those geographic regions with higher frequency of the Hpt2 allele (conversely, lower frequency of Hpt1 allele) would correlate with an increased incidence of MS, because different Hpt phenotypes will have variable anti-oxidative potentials in protecting myelin from damage inflicted by extracellular Hb and its degradation products. To test this hypothesis, we undertook a systematic analysis of the literature on reported geographic distributions of Hpt alleles to compare them with data reported in the World Health Organization Atlas of worldwide MS prevalence. We found the frequency of the Hpt1 allele to be low in European and North American countries with a high prevalence of MS, consistent with our hypothesis. However, this correlation was not observed in China and India, countries with the lowest Hpt1 frequencies, yet low reported prevalence of MS. Nevertheless, this work shows the need for continued refinement of geographic patterns of MS prevalence, including data on ethnic or racial origin, and for new clinical studies to probe the observed correlation and evaluate Hpt phenotype as a predictor of disease variability and progression, severity, and/or comorbidity with cardiovascular disorders.

  6. Multi-level Control Framework for Enhanced Flexibility of Active Distribution Network

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    In this paper, the control objectives of future active distribution networks with high penetration of renewables and flexible loads are analyzed and reviewed. From a state of the art review, the important control objectives seen from the perspective of a distribution system operator are identifie......-ordination and management of the network assets at different voltage levels and geographical locations. The paper finally shows the applicability of the multi-level control architecture to some of the key challenges in the distribution system operation by relevant scenarios....... to be hosting capacity improvement, high reliable operation and cost effective network management. Based on this review and a state of the art review concerning future distribution network control methods, a multi-level control architecture is constructed for an active distribution network, which satisfies...... the selected control objectives and provides enhanced flexibility. The control architecture is supported by generation/load forecasting and distribution state estimation techniques to improve the controllability of the network. The multi-level control architecture consists of three levels of hierarchical...

  7. Host tolerance, not symbiont tolerance, determines the distribution of coral species in relation to their environment at a Central Pacific atoll

    Science.gov (United States)

    Wicks, L. C.; Gardner, J. P. A.; Davy, S. K.

    2012-06-01

    Tolerance of environmental variables differs between corals and their dinoflagellate symbionts ( Symbiodinium spp.), controlling the holobiont's (host and symbiont combined) resilience to environmental stress. However, the ecological role that environmental variables play in holobiont distribution remains poorly understood. We compared the drivers of symbiont and coral species distributions at Palmyra Atoll, a location with a range of reef environments from low to high sediment concentrations (1-52 g dry weight m-2 day-1). We observed uniform holobiont partnerships across the atoll (e.g. Montipora spp. with Symbiodinium type C15 at all sites). Multivariate analysis revealed that field-based estimates of settling sediment predominantly explained the spatial variation of coral species among sites ( P coral rather than Symbiodinium physiology. The data highlight the importance of host tolerance to environmental stressors, which should be considered simultaneously with symbiont sensitivity when considering the impact of variations in environmental conditions on coral communities.

  8. Changes in the geographical distribution and abundance of the tick Ixodes ricinus during the past 30 years in Sweden

    Directory of Open Access Journals (Sweden)

    Jaenson Thomas GT

    2012-01-01

    respondents, the abundance of ticks had increased markedly in LB- and TBE-endemic areas in South (Götaland and Central Sweden. Conclusions The results suggest that I. ricinus has expanded its range in North Sweden and has become distinctly more abundant in Central and South Sweden during the last three decades. However, in the northern mountain region I. ricinus is still absent. The increased abundance of the tick can be explained by two main factors: First, the high availability of large numbers of important tick maintenance hosts, i.e., cervids, particularly roe deer (Capreolus capreolus during the last three decades. Second, a warmer climate with milder winters and a prolonged growing season that permits greater survival and proliferation over a larger geographical area of both the tick itself and deer. High reproductive potential of roe deer, high tick infestation rate and the tendency of roe deer to disperse great distances may explain the range expansion of I. ricinus and particularly the appearance of new TBEV foci far away from old TBEV-endemic localities. The geographical presence of LB in Sweden corresponds to the distribution of I. ricinus. Thus, LB is now an emerging disease risk in many parts of North Sweden. Unless countermeasures are undertaken to keep the deer populations, particularly C. capreolus and Dama dama, at the relatively low levels that prevailed before the late 1970s - especially in and around urban areas where human population density is high - by e.g. reduced hunting of red fox (Vulpes vulpes and lynx (Lynx lynx, the incidences of human LB and TBE are expected to continue to be high or even to increase in Sweden in coming decades.

  9. Changes in the geographical distribution and abundance of the tick Ixodes ricinus during the past 30 years in Sweden.

    Science.gov (United States)

    Jaenson, Thomas G T; Jaenson, David G E; Eisen, Lars; Petersson, Erik; Lindgren, Elisabet

    2012-01-10

    markedly in LB- and TBE-endemic areas in South (Götaland) and Central Sweden. The results suggest that I. ricinus has expanded its range in North Sweden and has become distinctly more abundant in Central and South Sweden during the last three decades. However, in the northern mountain region I. ricinus is still absent. The increased abundance of the tick can be explained by two main factors: First, the high availability of large numbers of important tick maintenance hosts, i.e., cervids, particularly roe deer (Capreolus capreolus) during the last three decades. Second, a warmer climate with milder winters and a prolonged growing season that permits greater survival and proliferation over a larger geographical area of both the tick itself and deer. High reproductive potential of roe deer, high tick infestation rate and the tendency of roe deer to disperse great distances may explain the range expansion of I. ricinus and particularly the appearance of new TBEV foci far away from old TBEV-endemic localities. The geographical presence of LB in Sweden corresponds to the distribution of I. ricinus. Thus, LB is now an emerging disease risk in many parts of North Sweden. Unless countermeasures are undertaken to keep the deer populations, particularly C. capreolus and Dama dama, at the relatively low levels that prevailed before the late 1970s--especially in and around urban areas where human population density is high--by e.g. reduced hunting of red fox (Vulpes vulpes) and lynx (Lynx lynx), the incidences of human LB and TBE are expected to continue to be high or even to increase in Sweden in coming decades.

  10. Clustering and cellular distribution characteristics of virus particles of Tomato spotted wilt virus and Tomato zonate spot virus in different plant hosts.

    Science.gov (United States)

    Zhang, Zhongkai; Zheng, Kuanyu; Dong, Jiahong; Fang, Qi; Hong, Jian; Wang, Xifeng

    2016-01-19

    Tomato spotted wilt virus (TSWV) and Tomato zonate spot virus (TZSV) are the two dominant species of thrip-transmitted tospoviruses, cause significant losses in crop yield in Yunnan and its neighboring provinces in China. TSWV and TZSV belong to different serogroup of tospoviruses but induce similar symptoms in the same host plant species, which makes diagnostic difficult. We used different electron microscopy preparing methods to investigate clustering and cellular distribution of TSWV and TZSV in the host plant species. Negative staining of samples infected with TSWV and TZSV revealed that particles usually clustered in the vesicles, including single particle (SP), double particles clustering (DPC), triple particles clustering (TPC). In the immunogold labeling negative staining against proteins of TZSV, the antibodies against Gn protein were stained more strongly than the N protein. Ultrathin section and high pressure freeze (HPF)-electron microscopy preparations revealed that TSWV particles were distributed in the cisternae of endoplasmic reticulum (ER), filamentous inclusions (FI) and Golgi bodies in the mesophyll cells. The TSWV particles clustered as multiple particles clustering (MPC) and distributed in globular viroplasm or cisternae of ER in the top leaf cell. TZSV particles were distributed more abundantly in the swollen membrane of ER in the mesophyll cell than those in the phloem parenchyma cells and were not observed in the top leaf cell. However, TZSV virions were mainly present as single particle in the cytoplasm, with few clustering as MPC. In this study, we identified TSWV and TZSV particles had the distinct cellular distribution patterns in the cytoplasm from different tissues and host plants. This is the first report of specific clustering characteristics of tospoviruses particles as well as the cellular distribution of TSWV particles in the FI and globular viroplasm where as TZSV particles inside the membrane of ER. These results indicated that

  11. [Prediction and spatial distribution of recruitment trees of natural secondary forest based on geographically weighted Poisson model].

    Science.gov (United States)

    Zhang, Ling Yu; Liu, Zhao Gang

    2017-12-01

    Based on the data collected from 108 permanent plots of the forest resources survey in Maoershan Experimental Forest Farm during 2004-2016, this study investigated the spatial distribution of recruitment trees in natural secondary forest by global Poisson regression and geographically weighted Poisson regression (GWPR) with four bandwidths of 2.5, 5, 10 and 15 km. The simulation effects of the 5 regressions and the factors influencing the recruitment trees in stands were analyzed, a description was given to the spatial autocorrelation of the regression residuals on global and local levels using Moran's I. The results showed that the spatial distribution of the number of natural secondary forest recruitment was significantly influenced by stands and topographic factors, especially average DBH. The GWPR model with small scale (2.5 km) had high accuracy of model fitting, a large range of model parameter estimates was generated, and the localized spatial distribution effect of the model parameters was obtained. The GWPR model at small scale (2.5 and 5 km) had produced a small range of model residuals, and the stability of the model was improved. The global spatial auto-correlation of the GWPR model residual at the small scale (2.5 km) was the lowe-st, and the local spatial auto-correlation was significantly reduced, in which an ideal spatial distribution pattern of small clusters with different observations was formed. The local model at small scale (2.5 km) was much better than the global model in the simulation effect on the spatial distribution of recruitment tree number.

  12. Human migration, railways and the geographic distribution of leprosy in Rio Grande do Norte State – Brazil

    Science.gov (United States)

    Nobre, Mauricio Lisboa; Dupnik, Kathryn Margaret; Nobre, Paulo José Lisboa; De Souza, Márcia Célia Freitas; Dűppre, Nádia Cristina; Sarno, Euzenir Nunes; Jerŏnimo, Selma Maria Bezerra

    2016-01-01

    Summary Introduction Leprosy is a public health problem in Brazil where 31,044 new cases were detected in 2013. Rio Grande do Norte is a small Brazilian state with a rate of leprosy lower than other areas in the same region, for unknown reasons. Objectives We present here a review based on the analysis of a database of registered leprosy cases in Rio Grande do Norte state, comparing leprosy's geographic distribution among municipalities with local socio-economic and public health indicators and with historical documents about human migration in this Brazilian region. Results The current distribution of leprosy in Rio Grande do Norte did not show correlation with socio-economic or public health indicators at the municipal level, but it appears related to economically emerging municipalities 100 years ago, with spread facilitated by railroads and train stations. Drought-related migratory movements which occurred from this state to leprosy endemic areas within the same period may be involved in the introduction of leprosy and with its present distribution within Rio Grande do Norte. Conclusions Leprosy may disseminate slowly, over many decades in certain circumstances, such as in small cities with few cases. This is a very unusual situation currently and a unique opportunity for epidemiologic studies of leprosy as an emerging disease. PMID:26964429

  13. Surveying and Mapping Geographical Information from the Perspective of Geography

    Directory of Open Access Journals (Sweden)

    LÜ Guonian

    2017-10-01

    Full Text Available It briefly reviewed the history of geographic information content development since the existence of geographic information system. It pointed out that the current definition of geographic information is always the extension from the "spatial+ attributes" basic mapping framework of geographic information. It is increasingly difficult to adapt to the analysis and application of spatial-temporal big data. From the perspective of geography research subject and content, it summarized systematically that the content and extension of the "geographic information" that geography needs. It put forward that a six-element expression model of geographic information, including spatial location, semantic description, attribute characteristics, geometric form, evolution process, and objects relationship.Under the guidance of the laws of geography, for geographical phenomenon of spatial distribution, temporal pattern and evolution process, the interaction mechanism of the integrated expression, system analysis and efficient management, it designed that a unified GIS data model which is expressed by six basic elements, a new GIS data structure driven by geographical rules and interaction, and key technologies of unstructured spatio-temporal data organization and storage. It provided that a theoretical basis and technical support for the shift from the surveying and mapping geographic information to the scientific geographic information, and it can help improving the organization, management, analysis and expression ability of the GIS of the geographical laws such as geographical pattern, evolution process, and interaction between elements.

  14. HOST PLANT UTILIZATION, HOST RANGE OSCILLATIONS AND DIVERSIFICATION IN NYMPHALID BUTTERFLIES: A PHYLOGENETIC INVESTIGATION

    Science.gov (United States)

    Nylin, Sören; Slove, Jessica; Janz, Niklas

    2014-01-01

    It has been suggested that phenotypic plasticity is a major factor in the diversification of life, and that variation in host range in phytophagous insects is a good model for investigating this claim. We explore the use of angiosperm plants as hosts for nymphalid butterflies, and in particular the evidence for past oscillations in host range and how they are linked to host shifts and to diversification. At the level of orders of plants, a relatively simple pattern of host use and host shifts emerges, despite the 100 million years of history of the family Nymphalidae. We review the evidence that these host shifts and the accompanying diversifications were associated with transient polyphagous stages, as suggested by the “oscillation hypothesis.” In addition, we investigate all currently polyphagous nymphalid species and demonstrate that the state of polyphagy is rare, has a weak phylogenetic signal, and a very apical distribution in the phylogeny; we argue that these are signs of its transient nature. We contrast our results with data from the bark beetles Dendroctonus, in which a more specialized host use is instead the apical state. We conclude that plasticity in host use is likely to have contributed to diversification in nymphalid butterflies. PMID:24372598

  15. [Distribution diversity of integrins and calcium channels on major human and mouse host cells of Leptospira species].

    Science.gov (United States)

    Li, Cheng-xue; Zhao, Xin; Qian, Jing; Yan, Jie

    2012-07-01

    To determine the distribution of integrins and calcium channels on major human and mouse host cells of Leptospira species. The expression of β1, β2 and β3 integrins was detected with immunofluorescence assay on the surface of human monocyte line THP-1, mouse mononuclear-macrophage-like cell line J774A.1, human vascular endothelial cell line HUVEC, mouse vascular endothelial cell EOMA, human hepatocyte line L-02, mouse hepatocyte line Hepa1-6, human renal tubular epithelial cell line HEK-293, mouse glomerular membrane epithelial cell line SV40-MES13, mouse collagen blast line NIH/3T3, human and mouse platelets. The distribution of voltage gate control calcium channels Cav3.1, Cav3.2, Cav3.3 and Cav2.3, and receptor gate calcium channels P(2)X(1), P(2)2X(2), P(2)X(3), P(2)X(4), P(2)X(5), P(2)X(6) and P(2)X(7) were determined with Western blot assay. β1 integrin proteins were positively expressed on the membrane surface of J774A.1, THP-1, HUVEC, EOMA, L-02, Hepa1-6 and HEK-239 cells as well as human and mouse platelets. β2 integrin proteins were expressed on the membrane surface of J774A.1, THP-1, HUVEC, EOMA, and NIH/3T3 cells. β3 integrin proteins were expressed on the membrane surface of J774A.1, THP-1, HUVEC, EOMA, Hepa1-6, HEK-239 and NIH/3T3 cells as well as human and mouse platelets. P(2)X(1) receptor gate calcium channel was expressed on the membrane surface of human and mouse platelets, while P(2)X(5) receptor gate calcium channel was expressed on the membrane surface of J774A.1, THP-1, L-02, Hepa1-6, HEK-239 and HUVEC cells. However, the other calcium channels were not detected on the tested cell lines or platelets. There is a large distribution diversity of integrins and calcium channel proteins on the major human and mouse host cells of Leptospira species, which may be associated with the differences of leptospira-induced injury in different host cells.

  16. Geographic Distribution of Ammonia-Oxidizing Archaea along the Kuril Islands in the Western Subarctic Pacific

    Directory of Open Access Journals (Sweden)

    Hongmei Jing

    2017-06-01

    Full Text Available Community composition and abundance of ammonia-oxidizing archaea (AOA in the ocean were affected by different physicochemical conditions, but their responses to physical barriers (such as a chain of islands were largely unknown. In our study, geographic distribution of the AOA from the surface photic zone to the deep bathypelagic waters in the western subarctic Pacific adjacent to the Kuril Islands was investigated using pyrosequencing based on the ammonia monooxygenase subunit A (amoA gene. Genotypes of clusters A and B dominated in the upper euphotic zone and the deep waters, respectively. Quantitative PCR assays revealed that the occurrence and ammonia-oxidizing activity of ammonia-oxidizing archaea (AOA reached their maxima at the depth of 200 m, where a higher diversity and abundance of actively transcribed AOA was observed at the station located in the marginal sea exposed to more terrestrial input. Similar community composition of AOA observed at the two stations adjacent to the Kuril Islands maybe due to water exchange across the Bussol Strait. They distinct from the station located in the western subarctic gyre, where sub-cluster WCAII had a specific distribution in the surface water, and this sub-cluster seemed having a confined distribution in the western Pacific. Habitat-specific groupings of different WCB sub-clusters were observed reflecting the isolated microevolution existed in cluster WCB. The effect of the Kuril Islands on the phylogenetic composition of AOA between the Sea of Okhotsk and the western subarctic Pacific is not obvious, possibly because our sampling stations are near to the Bussol Strait, the main gateway through which water is exchanged between the Sea of Okhotsk and the Pacific. The vertical and horizontal distribution patterns of AOA communities among stations along the Kuril Islands were essentially determined by the in situ prevailing physicochemical gradients along the two dimensions.

  17. Phytophthora ramorum is a generalist plant pathogen with differences in virulence between isolates from infectious and dead-end hosts

    Science.gov (United States)

    D. Huberli; M. Garbelotto

    2011-01-01

    Variation in virulence was examined among isolates of Phytophthora ramorum from epidemiologically important or infectious (non-oak) and transmissive dead-end (oak) hosts from North America. Twelve isolates representative of the genetic, geographic and host range of P. ramorum in the western United States were inoculated on...

  18. Natural Scales in Geographical Patterns

    Science.gov (United States)

    Menezes, Telmo; Roth, Camille

    2017-04-01

    Human mobility is known to be distributed across several orders of magnitude of physical distances, which makes it generally difficult to endogenously find or define typical and meaningful scales. Relevant analyses, from movements to geographical partitions, seem to be relative to some ad-hoc scale, or no scale at all. Relying on geotagged data collected from photo-sharing social media, we apply community detection to movement networks constrained by increasing percentiles of the distance distribution. Using a simple parameter-free discontinuity detection algorithm, we discover clear phase transitions in the community partition space. The detection of these phases constitutes the first objective method of characterising endogenous, natural scales of human movement. Our study covers nine regions, ranging from cities to countries of various sizes and a transnational area. For all regions, the number of natural scales is remarkably low (2 or 3). Further, our results hint at scale-related behaviours rather than scale-related users. The partitions of the natural scales allow us to draw discrete multi-scale geographical boundaries, potentially capable of providing key insights in fields such as epidemiology or cultural contagion where the introduction of spatial boundaries is pivotal.

  19. [Geographic distribution and exposure population of drinking water with high concentration of arsenic in China].

    Science.gov (United States)

    Zhang, L; Chen, C

    1997-09-01

    According to the data obtained from the "National Survey on Drinking Water Quality and Waterborne Diseases", the geographic distribution and exposure population of high arsenic drinking water were reported. From the data of more than 28,800 water samples, we found 9.02 million people drinking the water with As concentration of 0.030-0.049 mg/L, 3.34 million people having their water of 0.050-0.099 mg/L and 2.29 million people having water of > 0.1 mg/L. A total of 14.6 million people, about 1.5% of the surveyed population was exposed to As (> 0.030 mg/L) from drinking water. 80% of high-As-drinking water was groundwater. The situation of As in drinking water in provinces, autonomous regions and municipalities were listed. The locations of sampling site where water As exceeded the national standard for drinking water were illustrated.

  20. Monitoring potential geographical distribution of four wild bird species in China

    Science.gov (United States)

    Dai, S.; Feng, D.; Xu, B.

    2015-12-01

    The outbreak of highly pathogenic avian influenza (HPAI) of the H5N1 subtype in wild birds and poultry have caught worldwide attention. To explore the association between wild bird migration and avian influenza virus transmission, we monitored potential geographical distribution of four wild bird species that might carry the avian influenza viruses in China. They are Bar-headed geese (Anser indicus), Ruddy Shelduck (Tadorna ferruginea), Whooper Swan (Cygnus cygnus) and Black-headed Gull (Larus ridibundus). They served as major reservoir of the avian influenza viruses. We used bird watching records with the precise latitude/longitude coordinates from January 2002 to August 2014, and environmental variables with a pixel resolution of 5 km × 5 km from 2002 to 2014. The study utilized maximum entropy (MaxEnt) model based on ecological niche model approaches, and got the following results: 1) MaxEnt model have good discriminatory ability with the area under the curve (AUC) of the receiver operating curve (ROC) of 0.86-0.97; 2) The four wild bird species were estimated to concentrate in the North China Plain, the middle and lower region of the Yangtze River, Qinghai Lake, Tianshan Mountain and Tarim Basin, part of Tibet Plateau, and Hengduan Mountains; 3) Radiation and the minimum temperature were found to provide the most significant information. Our findings will help to understand the spread of avian influenza viruses by wild bird migration in China, which benefits for effective monitoring strategies and prevention measures.

  1. Targeting hunter distribution based on host resource selection and kill sites to manage disease risk.

    Science.gov (United States)

    Dugal, Cherie J; van Beest, Floris M; Vander Wal, Eric; Brook, Ryan K

    2013-10-01

    Endemic and emerging diseases are rarely uniform in their spatial distribution or prevalence among cohorts of wildlife. Spatial models that quantify risk-driven differences in resource selection and hunter mortality of animals at fine spatial scales can assist disease management by identifying high-risk areas and individuals. We used resource selection functions (RSFs) and selection ratios (SRs) to quantify sex- and age-specific resource selection patterns of collared (n = 67) and hunter-killed (n = 796) nonmigratory elk (Cervus canadensis manitobensis) during the hunting season between 2002 and 2012, in southwestern Manitoba, Canada. Distance to protected area was the most important covariate influencing resource selection and hunter-kill sites of elk (AICw = 1.00). Collared adult males (which are most likely to be infected with bovine tuberculosis (Mycobacterium bovis) and chronic wasting disease) rarely selected for sites outside of parks during the hunting season in contrast to adult females and juvenile males. The RSFs showed selection by adult females and juvenile males to be negatively associated with landscape-level forest cover, high road density, and water cover, whereas hunter-kill sites of these cohorts were positively associated with landscape-level forest cover and increasing distance to streams and negatively associated with high road density. Local-level forest was positively associated with collared animal locations and hunter-kill sites; however, selection was stronger for collared juvenile males and hunter-killed adult females. In instances where disease infects a metapopulation and eradication is infeasible, a principle goal of management is to limit the spread of disease among infected animals. We map high-risk areas that are regularly used by potentially infectious hosts but currently underrepresented in the distribution of kill sites. We present a novel application of widely available data to target hunter distribution based on host resource

  2. [Analysis on geographic distribution of high blood pressure prevalence in children and adolescents aged 7-18 years in China, 2014].

    Science.gov (United States)

    Dong, Y H; Zou, Z Y; Wang, Z H; Wang, S; Yang, Z P; Chen, Y J; Ma, J

    2017-07-10

    Objective: To understand and evaluate the characteristics of geographic distribution of high blood pressure prevalence in children and adolescents aged 7-18 years in China in 2014, and provide evidence for the prevention of hypertension in children and adolescents. Methods: The data of 2014 Chinese National Surveys on Students Constitution and Health conducting 31 provinces (except Hong Kong, Macao and Taiwan) were collected. A total of 216 299 children and adolescents who had complete blood pressure records were selected as study subjects. The low, middle and high prevalence areas were identified according to their high blood pressure detection rates in the children and adolescents,7 % , to analyze the geographic distribution of high blood pressure prevalence in the children and adolescents. The environmental data in the capitals of 31 provinces in 2014 were collected to analyze the correlation between environmental factors and blood pressure Z score in the children and adolescents. Results: The average detection rates of high blood pressure was 6.4 % in 31 provinces (1.5 % -14.2 % ). The high prevalence areas were mainly distributed in the eastern China, especially the Circum-Bohai sea area, low prevalence areas were mainly distributed in the central and western areas of China and some provinces in the east. Correlation analysis results showed that the annual average temperature, annual average air humidity and local altitude were negatively correlated with blood pressure Z score, including diastolic and systolic blood pressure, in both boys and girls. The annual average sunshine time, PM(2.5) and PM(10) concentrations, content of SO(2) were positively correlated with blood pressure Z score in both boys and girls. Conclusions: There was a significant difference in high blood pressure of children and adolescents among 31 provinces. More attention should be paid to the children and adolescents living high prevalence area. And it is necessary to understand

  3. Phylogenetic isolation of host trees affects assembly of local Heteroptera communities

    NARCIS (Netherlands)

    Vialatte, A.; Bailey, R.; Vasseur, C.; Matocq, A.; Gossner, M.; Everhart, D.; Vitrac, X.; Belhadj, A.; Ernoult, A.; Prinzing, A.

    2010-01-01

    A host may be physically isolated in space and then may correspond to a geographical island, but it may also be separated from its local neighbours by hundreds of millions of years of evolutionary history, and may form in this case an evolutionarily distinct island. We test how this affects the

  4. Estimating the accuracy of geographical imputation

    Directory of Open Access Journals (Sweden)

    Boscoe Francis P

    2008-01-01

    Full Text Available Abstract Background To reduce the number of non-geocoded cases researchers and organizations sometimes include cases geocoded to postal code centroids along with cases geocoded with the greater precision of a full street address. Some analysts then use the postal code to assign information to the cases from finer-level geographies such as a census tract. Assignment is commonly completed using either a postal centroid or by a geographical imputation method which assigns a location by using both the demographic characteristics of the case and the population characteristics of the postal delivery area. To date no systematic evaluation of geographical imputation methods ("geo-imputation" has been completed. The objective of this study was to determine the accuracy of census tract assignment using geo-imputation. Methods Using a large dataset of breast, prostate and colorectal cancer cases reported to the New Jersey Cancer Registry, we determined how often cases were assigned to the correct census tract using alternate strategies of demographic based geo-imputation, and using assignments obtained from postal code centroids. Assignment accuracy was measured by comparing the tract assigned with the tract originally identified from the full street address. Results Assigning cases to census tracts using the race/ethnicity population distribution within a postal code resulted in more correctly assigned cases than when using postal code centroids. The addition of age characteristics increased the match rates even further. Match rates were highly dependent on both the geographic distribution of race/ethnicity groups and population density. Conclusion Geo-imputation appears to offer some advantages and no serious drawbacks as compared with the alternative of assigning cases to census tracts based on postal code centroids. For a specific analysis, researchers will still need to consider the potential impact of geocoding quality on their results and evaluate

  5. Walking response of the Mediterranean pine engraver, Orthotomicus erosus, to novel plant odors host in a laboratory olfactometer

    Science.gov (United States)

    A. J. Walter; R. C. Venette; S. A. Kells; S. J. Seybold

    2010-01-01

    When an herbivorous insect enters a new geographic area, it will select host plants based on short and long distance cues. A conifer-feeding bark beetle that has been recently introduced to North America, the Mediterranean pine engraver, Orthotomicus erosus (Wollaston), has a potentially wide host range, especially among members of the Pinaceae....

  6. An assessment of geographical distribution of different plant functional types over North America simulated using the CLASS-CTEM modelling framework

    Science.gov (United States)

    Shrestha, Rudra K.; Arora, Vivek K.; Melton, Joe R.; Sushama, Laxmi

    2017-10-01

    The performance of the competition module of the CLASS-CTEM (Canadian Land Surface Scheme and Canadian Terrestrial Ecosystem Model) modelling framework is assessed at 1° spatial resolution over North America by comparing the simulated geographical distribution of its plant functional types (PFTs) with two observation-based estimates. The model successfully reproduces the broad geographical distribution of trees, grasses and bare ground although limitations remain. In particular, compared to the two observation-based estimates, the simulated fractional vegetation coverage is lower in the arid southwest North American region and higher in the Arctic region. The lower-than-observed simulated vegetation coverage in the southwest region is attributed to lack of representation of shrubs in the model and plausible errors in the observation-based data sets. The observation-based data indicate vegetation fractional coverage of more than 60 % in this arid region, despite only 200-300 mm of precipitation that the region receives annually, and observation-based leaf area index (LAI) values in the region are lower than one. The higher-than-observed vegetation fractional coverage in the Arctic is likely due to the lack of representation of moss and lichen PFTs and also likely because of inadequate representation of permafrost in the model as a result of which the C3 grass PFT performs overly well in the region. The model generally reproduces the broad spatial distribution and the total area covered by the two primary tree PFTs (needleleaf evergreen trees, NDL-EVG; and broadleaf cold deciduous trees, BDL-DCD-CLD) reasonably well. The simulated fractional coverage of tree PFTs increases after the 1960s in response to the CO2 fertilization effect and climate warming. Differences between observed and simulated PFT coverages highlight model limitations and suggest that the inclusion of shrubs, and moss and lichen PFTs, and an adequate representation of permafrost will help improve

  7. Host shifts enhance diversification of ectomycorrhizal fungi: diversification rate analysis of the ectomycorrhizal fungal genera Strobilomyces and Afroboletus with an 80-gene phylogeny.

    Science.gov (United States)

    Sato, Hirotoshi; Tanabe, Akifumi S; Toju, Hirokazu

    2017-04-01

    Mutualisms with new host lineages can provide symbionts with novel ecological opportunities to expand their geographical distribution, thereby leading to evolutionary diversification. Because ectomycorrhizal (ECM) fungi provide ideal opportunities to test the relationship between host shifts and diversification, we tested whether mutualism with new host lineages could increase the diversification rates of ECM fungi. Using a Bayesian tree inferred from 23 027-base nucleotide sequences of 80 single-copy genes, we tested whether the diversification rate had changed through host-shift events in the monophyletic clade containing the ECM fungal genera Strobilomyces and Afroboletus. The results indicated that these fungi were initially associated with Caesalpinioideae/Monotoideae in Africa, acquired associations with Dipterocarpoideae in tropical Asia, and then switched to Fagaceae/Pinaceae and Nothofagaceae/Eucalyptus. Fungal lineages associated with Fagaceae/Pinaceae were inferred to have approximately four-fold and two-fold greater diversification rates than those associated with Caesalpinioideae/Monotoideae and Dipterocarpoideae or Nothofagaceae/Eucalyptus, respectively. Moreover, the diversification rate shift was inferred to follow the host shift to Fagaceae/Pinaceae. Our study suggests that host-shift events, particularly those occurring with respect to Fagaceae/Pinaceae, can provide ecological opportunities for the rapid diversification of Strobilomyces-Afroboletus. Although further studies are needed for generalization, we propose a possible diversification scenario of ECM fungi. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  8. Global Distribution, Public Health and Clinical Impact of the Protozoan Pathogen Cryptosporidium

    Directory of Open Access Journals (Sweden)

    Lorenza Putignani

    2010-01-01

    Full Text Available Cryptosporidium spp. are coccidians, oocysts-forming apicomplexan protozoa, which complete their life cycle both in humans and animals, through zoonotic and anthroponotic transmission, causing cryptosporidiosis. The global burden of this disease is still underascertained, due to a conundrum transmission modality, only partially unveiled, and on a plethora of detection systems still inadequate or only partially applied for worldwide surveillance. In children, cryptosporidiosis encumber is even less recorded and often misidentified due to physiological reasons such as early-age unpaired immunological response. Furthermore, malnutrition in underdeveloped countries or clinical underestimation of protozoan etiology in developed countries contribute to the underestimation of the worldwide burden. Principal key indicators of the parasite distribution were associated to environmental (e.g., geographic and temporal clusters, etc. and host determinants of the infection (e.g., age, immunological status, travels, community behaviours. The distribution was geographically mapped to provide an updated picture of the global parasite ecosystems. The present paper aims to provide, by a critical analysis of existing literature, a link between observational epidemiological records and new insights on public health, and diagnostic and clinical impact of cryptosporidiosis.

  9. Host nutrition alters the variance in parasite transmission potential.

    Science.gov (United States)

    Vale, Pedro F; Choisy, Marc; Little, Tom J

    2013-04-23

    The environmental conditions experienced by hosts are known to affect their mean parasite transmission potential. How different conditions may affect the variance of transmission potential has received less attention, but is an important question for disease management, especially if specific ecological contexts are more likely to foster a few extremely infectious hosts. Using the obligate-killing bacterium Pasteuria ramosa and its crustacean host Daphnia magna, we analysed how host nutrition affected the variance of individual parasite loads, and, therefore, transmission potential. Under low food, individual parasite loads showed similar mean and variance, following a Poisson distribution. By contrast, among well-nourished hosts, parasite loads were right-skewed and overdispersed, following a negative binomial distribution. Abundant food may, therefore, yield individuals causing potentially more transmission than the population average. Measuring both the mean and variance of individual parasite loads in controlled experimental infections may offer a useful way of revealing risk factors for potential highly infectious hosts.

  10. Temporal and spatial alterations in mutant swarm size of St. Louis encephalitis virus in mosquito hosts.

    Science.gov (United States)

    Ciota, Alexander T; Koch, Evan M; Willsey, Graham G; Davis, Lauren J; Jerzak, Greta V S; Ehrbar, Dylan J; Wilke, Claus O; Kramer, Laura D

    2011-03-01

    St. Louis encephalitis virus (SLEV; Flaviviridae; Flavivirus) is a member of the Japanese encephalitis serocomplex and a close relative of West Nile virus (WNV). Although SLEV remains endemic to the US, both levels of activity and geographical dispersal are relatively constrained when compared to the widespread distribution of WNV. In recent years, WNV appears to have displaced SLEV in California, yet both viruses currently coexist in Texas and several other states. It has become clear that viral swarm characterization is required if we are to fully evaluate the relationship between viral genomes, viral evolution, and epidemiology. Mutant swarm size and composition may be particularly important for arboviruses, which require replication not only in diverse tissues but also divergent hosts. In order to evaluate temporal, spatial, and host-specific patterns in the SLEV mutant swarm, we determined the size, composition, and phylogeny of the intrahost swarm within primary mosquito isolates from both Texas and California. Results indicate a general trend of decreasing intrahost diversity over time in both locations, with recent isolates being highly genetically homogeneous. Additionally, phylogenic analyses provide detailed information on the relatedness of minority variants both within and among strains and demonstrate how both geographic isolation and seasonal maintenance have shaped the viral swarm. Overall, these data generally provide insight into how time, space, and unique transmission cycles influence the SLEV mutant swarm and how understanding these processes can ultimately lead to a better understanding of arbovirus evolution and epidemiology. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Stoneflies (Plecoptera) of the Gunnison Basin: A Geographical Study of Current Versus Historical Distributions.

    Science.gov (United States)

    Wright, J.; Townsend, A.; Alexander, K.

    2005-05-01

    We compared the stonefly diversity sampled from 11 selected sites in the Gunnison River Basin over the last three years to the stonefly diversity recorded by Knight (1965) from the same or nearby sites. The 11 sites in this study were chosen from the 22 sites reported by Knight (1965) because they represented mainstem Gunnison River sites that would be predicted to experience the most alteration due to anthropogenic changes such as the construction of impoundments, differences in land use patterns, and effects from the increase in human population of the region. We have been unable to locate ten of the stonefly species that were historically found and we presume that they have gone locally extinct or have become increasingly rare. We have also found six species present today that were not historically reported from Knight (1965). Maps showing current and historical stonefly diversity and distribution have been produced using ArcGIS and analyzed with relevant geographical data to form hypotheses to account for specific changes in the stonefly fauna of the basin.

  12. Whole Genome Sequencing of Mycobacterium africanum Strains from Mali Provides Insights into the Mechanisms of Geographic Restriction.

    Science.gov (United States)

    Winglee, Kathryn; Manson McGuire, Abigail; Maiga, Mamoudou; Abeel, Thomas; Shea, Terrance; Desjardins, Christopher A; Diarra, Bassirou; Baya, Bocar; Sanogo, Moumine; Diallo, Souleymane; Earl, Ashlee M; Bishai, William R

    2016-01-01

    Mycobacterium africanum, made up of lineages 5 and 6 within the Mycobacterium tuberculosis complex (MTC), causes up to half of all tuberculosis cases in West Africa, but is rarely found outside of this region. The reasons for this geographical restriction remain unknown. Possible reasons include a geographically restricted animal reservoir, a unique preference for hosts of West African ethnicity, and an inability to compete with other lineages outside of West Africa. These latter two hypotheses could be caused by loss of fitness or altered interactions with the host immune system. We sequenced 92 MTC clinical isolates from Mali, including two lineage 5 and 24 lineage 6 strains. Our genome sequencing assembly, alignment, phylogeny and average nucleotide identity analyses enabled us to identify features that typify lineages 5 and 6 and made clear that these lineages do not constitute a distinct species within the MTC. We found that in Mali, lineage 6 and lineage 4 strains have similar levels of diversity and evolve drug resistance through similar mechanisms. In the process, we identified a putative novel streptomycin resistance mutation. In addition, we found evidence of person-to-person transmission of lineage 6 isolates and showed that lineage 6 is not enriched for mutations in virulence-associated genes. This is the largest collection of lineage 5 and 6 whole genome sequences to date, and our assembly and alignment data provide valuable insights into what distinguishes these lineages from other MTC lineages. Lineages 5 and 6 do not appear to be geographically restricted due to an inability to transmit between West African hosts or to an elevated number of mutations in virulence-associated genes. However, lineage-specific mutations, such as mutations in cell wall structure, secretion systems and cofactor biosynthesis, provide alternative mechanisms that may lead to host specificity.

  13. The impact of travel time on geographic distribution of dialysis patients.

    Science.gov (United States)

    Kashima, Saori; Matsumoto, Masatoshi; Ogawa, Takahiko; Eboshida, Akira; Takeuchi, Keisuke

    2012-01-01

    The geographic disparity of prevalence rates among dialysis patients is unclear. We evaluate the association between travel time to dialysis facilities and prevalence rates of dialysis patients living in 1,867 census areas of Hiroshima, Japan. Furthermore, we study the effects of geographic features (mainland or island) on the prevalence rates and assess if these effects modify the association between travel time and prevalence. The study subjects were all 7,374 people that were certified as the "renal disabled" by local governments in 2011. The travel time from each patient to the nearest available dialysis facility was calculated by incorporating both travel time and the capacity of all 98 facilities. The effect of travel time on the age- and sex-adjusted standard prevalence rate (SPR) and 95% confidence intervals (CIs) at each census area was evaluated in two-level Poisson regression models with 1,867 census areas (level 1) nested within 35 towns or cities (level 2). The results were adjusted for area-based parameters of socioeconomic status, urbanity, and land type. Furthermore, the SPR of dialysis patients was calculated in each specific subgroup of population for travel time, land type, and combination of land type and travel time. In the regression analysis, SPR decreased by 5.2% (95% CI: -7.9--2.3) per 10-min increase in travel time even after adjusting for potential confounders. The effect of travel time on prevalence was different in the mainland and island groups. There was no travel time-dependent SPR disparity on the islands. The SPR among remote residents (>30 min from facilities) in the mainland was lower (0.77, 95% CI: 0.71-0.85) than that of closer residents (≤ 30 min; 0.95, 95% CI: 0.92-0.97). The prevalence of dialysis patients was lower among remote residents. Geographic difficulties for commuting seem to decrease the prevalence rate.

  14. Distributed generation hosting capacity calculation of MV distribution feeders in Turkey

    DEFF Research Database (Denmark)

    Altin, Müfit; Oguz, Emre Utku; Bizkevelci, Erdal

    2014-01-01

    Integration of distributed generation into distribution networks introduces new challenges to distribution system operators while the penetration level increases. One of the challenges is the voltage rise issue as a part of the steady-state analysis of DGs during planning and operational stages. ...

  15. Inferring geographic isolation of wolverines in California using historical DNA

    Science.gov (United States)

    Michael K. Schwartz; Keith B. Aubry; Kevin S. McKelvey; Kristine L. Pilgrim; Jeffrey P. Copeland; John R. Squires; Robert M. Inman; Samantha M. Wisely; Leonard F. Ruggiero

    2007-01-01

    Delineating a species' geographic range using the spatial distribution of museum specimens or even contemporary detection-non-detection data can be difficult. This is particularly true at the periphery of a species range where species' distributions are often disjunct. Wolverines (Gulo gulo) are wide-ranging mammals with discontinuous and...

  16. Bacterial communities differ among Drosophila melanogaster populations and affect host resistance against parasitoids

    NARCIS (Netherlands)

    Chaplinska, Mariia; Gerritsma, Sylvia; Dini-Andreote, Francisco; Falcao Salles, Joana; Wertheim, Bregje

    2016-01-01

    In Drosophila, diet is considered a prominent factor shaping the associated bacterial community. However, the host population background (e.g. genotype, geographical origin and founder effects) is a factor that may also exert a significant influence and is often overlooked. To test for population

  17. Accidental hazardous material releases with human impacts in the United States: exploration of geographical distribution and temporal trends.

    Science.gov (United States)

    Sengul, Hatice; Santella, Nicholas; Steinberg, Laura J; Chermak, Christina

    2010-09-01

    To investigate the circumstances and geographic and temporal distributions of hazardous material releases and resulting human impacts in the United States. Releases with fatalities, injuries, and evacuations were identified from reports to the National Response Center between 1990 and 2008, correcting for data quality issues identified in previous studies. From more than 550,000 reports, 861 deaths, 16,348 injuries and 741,427 evacuations were identified. Injuries from releases of chemicals at fixed facilities and natural gas from pipelines have decreased whereas evacuations from petroleum releases at fixed facilities have increased. Results confirm recent advances in chemical and pipeline safety and suggest directions for further improvement including targeted training and inspections and adoption of inherently safer design principles.

  18. A revision of distribution and historical analysis of preferred hosts of Orobanche ramosa (Orobanchaceae in Poland

    Directory of Open Access Journals (Sweden)

    Renata Piwowarczyk

    2012-12-01

    Full Text Available The Polish localities of Orobanche ramosa L., branched broomrape, are either extinct or have not been confirmed for many years. This paper presents two new localities of O. ramosa in Poland from the Płaskowyż Proszowicki plateau (Wyżyna Małopolska upland and the Nizina Nadwiślańska lowland (Kotlina Sandomierska basin. Habitat preferences and the abundance at the sites are described. A revised map of the distribution and a historical analysis of preferred hosts in Poland are included. The taxonomy, biology, ecology and control methods of O. ramosa are also discussed.

  19. Mesoscale spatiotemporal variability in a complex host-parasite system influenced by intermediate host body size.

    Science.gov (United States)

    Rodríguez, Sara M; Valdivia, Nelson

    2017-01-01

    Parasites are essential components of natural communities, but the factors that generate skewed distributions of parasite occurrences and abundances across host populations are not well understood. Here, we analyse at a seascape scale the spatiotemporal relationships of parasite exposure and host body-size with the proportion of infected hosts (i.e., prevalence) and aggregation of parasite burden across ca. 150 km of the coast and over 22 months. We predicted that the effects of parasite exposure on prevalence and aggregation are dependent on host body-sizes. We used an indirect host-parasite interaction in which migratory seagulls, sandy-shore molecrabs, and an acanthocephalan worm constitute the definitive hosts, intermediate hosts, and endoparasite, respectively. In such complex systems, increments in the abundance of definitive hosts imply increments in intermediate hosts' exposure to the parasite's dispersive stages. Linear mixed-effects models showed a significant, albeit highly variable, positive relationship between seagull density and prevalence. This relationship was stronger for small (cephalothorax length >15 mm) than large molecrabs (analysis of the variance-to-mean ratio of per capita parasite burden showed no relationship between seagull density and mean parasite aggregation across host populations. However, the amount of unexplained variability in aggregation was strikingly higher in larger than smaller intermediate hosts. This unexplained variability was driven by a decrease in the mean-variance scaling in heavily infected large molecrabs. These results show complex interdependencies between extrinsic and intrinsic population attributes on the structure of host-parasite interactions. We suggest that parasite accumulation-a characteristic of indirect host-parasite interactions-and subsequent increasing mortality rates over ontogeny underpin size-dependent host-parasite dynamics.

  20. On Optimal Geographical Caching in Heterogeneous Cellular Networks

    NARCIS (Netherlands)

    Serbetci, Berksan; Goseling, Jasper

    2017-01-01

    In this work we investigate optimal geographical caching in heterogeneous cellular networks where different types of base stations (BSs) have different cache capacities. Users request files from a content library according to a known probability distribution. The performance metric is the total hit

  1. No Geographic Correlation between Lyme Disease and Death Due to 4 Neurodegenerative Disorders, United States, 2001-2010.

    Science.gov (United States)

    Forrester, Joseph D; Kugeler, Kiersten J; Perea, Anna E; Pastula, Daniel M; Mead, Paul S

    2015-11-01

    Associations between Lyme disease and certain neurodegenerative diseases have been proposed, but supportive evidence for an association is lacking. Similar geographic distributions would be expected if 2 conditions were etiologically linked. Thus, we compared the distribution of Lyme disease cases in the United States with the distributions of deaths due to Alzheimer disease, amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and Parkinson disease; no geographic correlations were identified. Lyme disease incidence per US state was not correlated with rates of death due to ALS, MS, or Parkinson disease; however, an inverse correlation was detected between Lyme disease and Alzheimer disease. The absence of a positive correlation between the geographic distribution of Lyme disease and the distribution of deaths due to Alzheimer disease, ALS, MS, and Parkinson disease provides further evidence that Lyme disease is not associated with the development of these neurodegenerative conditions.

  2. The pollutants from livestock and poultry farming in China-geographic distribution and drivers.

    Science.gov (United States)

    Gan, Ling; Hu, Xisheng

    2016-05-01

    Livestock and poultry farming is a major source of agricultural pollution. However, our knowledge of the constraining factors of the geographic distribution of pollutants from livestock and poultry farming is still limited. In this study, using the optimized pollutant generation coefficients, we estimated the annual pollutant productions of eight livestock and poultry species at the provincial level in 2005 and 2013 and their growth rates during the study period in China; using canonical correlation analysis, we also explored the association between the eight pollutant measurements as dependent variables and 14 factors (including resource endowment, developmental level, and economic structure factors) as independent variables. Results indicate that there exist spatial disparity in the distribution of pollutants from livestock and poultry farming across regions, with provinces in the Huang-Huai-Hai region and the southwestern region accounting for approximately 50 % of the total productions in the nation. Cattle, pig, and poultry constitute the primary pollution sources in terms of livestock and poultry farming not only at the national level but also at the province level. While the species constitute and their respective growth rates of the pollutants can be also characterized by spatial disparity across regions, canonical correlation analysis shows that the observed regional patterns of the pollutants can be largely explained by the resource endowment factors (positive effects) and the developmental level factors (negative effects). In addition, we found that the development of livestock and poultry farming is negatively associated with the growing rate of both the resource endowment and the socioeconomic factors. This indicates that there exist different driving patterns in the gross and increment of the pollutant productions. Our research has significant implications for the appropriate environmental protection policy formulation and implementation in livestock

  3. Native fauna on exotic trees: phylogenetic conservatism and geographic contingency in two lineages of phytophages on two lineages of trees.

    Science.gov (United States)

    Gossner, Martin M; Chao, Anne; Bailey, Richard I; Prinzing, Andreas

    2009-05-01

    The relative roles of evolutionary history and geographical and ecological contingency for community assembly remain unknown. Plant species, for instance, share more phytophages with closer relatives (phylogenetic conservatism), but for exotic plants introduced to another continent, this may be overlaid by geographically contingent evolution or immigration from locally abundant plant species (mass effects). We assessed within local forests to what extent exotic trees (Douglas-fir, red oak) recruit phytophages (Coleoptera, Heteroptera) from more closely or more distantly related native plants. We found that exotics shared more phytophages with natives from the same major plant lineage (angiosperms vs. gymnosperms) than with natives from the other lineage. This was particularly true for Heteroptera, and it emphasizes the role of host specialization in phylogenetic conservatism of host use. However, for Coleoptera on Douglas-fir, mass effects were important: immigration from beech increased with increasing beech abundance. Within a plant phylum, phylogenetic proximity of exotics and natives increased phytophage similarity, primarily in younger Coleoptera clades on angiosperms, emphasizing a role of past codiversification of hosts and phytophages. Overall, phylogenetic conservatism can shape the assembly of local phytophage communities on exotic trees. Whether it outweighs geographic contingency and mass effects depends on the interplay of phylogenetic scale, local abundance of native tree species, and the biology and evolutionary history of the phytophage taxon.

  4. Model Checking Geographically Distributed Interlocking Systems Using UMC

    DEFF Research Database (Denmark)

    Fantechi, Alessandro; Haxthausen, Anne Elisabeth; Nielsen, Michel Bøje Randahl

    2017-01-01

    the relevant distributed protocols. By doing that we obey the safety guidelines of the railway signalling domain, that require formal methods to support the certification of such products. We also show how formal modelling can help designing alternative distributed solutions, while maintaining adherence...

  5. Geographic distribution of habitat, development, and population growth rates of the Asian citrus psyllid, Diaphorina citri, in Mexico.

    Science.gov (United States)

    López-Collado, José; Isabel López-Arroyo, J; Robles-García, Pedro L; Márquez-Santos, Magdalena

    2013-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an introduced pest in Mexico and a vector of huanglongbing, a lethal citrus disease. Estimations of the habitat distribution and population growth rates of D. citri are required to establish regional and areawide management strategies and can be used as a pest risk analysis tools. In this study, the habitat distribution of D. citri in Mexico was computed with MaxEnt, an inductive, machine-learning program that uses bioclimatic layers and point location data. Geographic distributions of development and population growth rates were determined by fitting a temperature-dependent, nonlinear model and projecting the rates over the target area, using the annual mean temperature as the predictor variable. The results showed that the most suitable regions for habitat of D. citri comprise the Gulf of Mexico states, Yucatán Peninsula, and areas scattered throughout the Pacific coastal states. Less suitable areas occurred in northern and central states. The most important predictor variables were related to temperature. Development and growth rates had a distribution wider than habitat, reaching some of the northern states of México. Habitat, development, and population growth rates were correlated to each other and with the citrus producing area. These relationships indicated that citrus producing states are within the most suitable regions for the occurrence, development, and population growth of D. citri, therefore increasing the risk of huanglongbing dispersion.

  6. Capacity of Physiotherapy Workforce Production in Thailand: Public-Private Mix, Secular Trend and Geographic Distribution.

    Science.gov (United States)

    Kaewsawang, Sarinee; Chongsuvivatwong, Virasakdi; Vongsirinavarat, Mantana

    2016-06-01

    In Thailand, the shortage of physiotherapists has been an increasing concern because of increased health burden from demographic and epidemiologic changes. This study aims to analyse the current situation of the physiotherapy workforce production system, secular trend, geographical distribution and comparison of public and private physiotherapy training institutes. Longitudinal data related to production capacity of the physiotherapy institutes were applied. Data from 2008 to 2012 were obtained from all 16 physiotherapy institutes in Thailand. Data during 2000-2007 were also retrieved from annual reports from the Ministry of Education. Descriptive statistics were initially used. Comparison was made between public and private physiotherapy institutes in terms of the number of students admitted and graduated, number of teachers, annual tuition fee, student-teacher ratio and dropout rate within 1 year. Predictive factors fo