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Sample records for geographical parthenogenesis general

  1. Diversity in the Reproductive Modes of European Daphnia pulicaria Deviates from the Geographical Parthenogenesis

    PubMed Central

    Vergilino, Roland; Ventura, Marc; Kotlík, Petr

    2011-01-01

    Background Multiple transitions to obligate parthenogenesis have occurred in the Daphnia pulex complex in North America. These newly formed asexual lineages are differentially distributed being found predominantly at high latitudes. This conforms to the rule of geographical parthenogenesis postulating prevalence of asexuals at high latitudes and altitudes. While the reproductive mode of high-latitude populations is relatively well studied, little is known about the reproduction mode in high altitudes. This study aimed to assess the reproductive mode of Daphnia pulicaria, a species of the D. pulex complex, from high altitude lakes in Europe. Methodology/Principal Findings Variation at eight microsatellite loci revealed that D. pulicaria from the High Tatra Mountains (HTM) had low genotype richness and showed excess of heterozygotes and significant deviations from Hardy-Weinberg expectations, and was thus congruent with reproduction by obligate parthenogenesis. By contrast, populations from the Pyrenees (Pyr) were generally in Hardy-Weinberg equilibrium and had higher genotypic richness, suggesting that they are cyclic parthenogens. Four lakes from lowland areas (LLaP) had populations with an uncertain or mixed breeding mode. All D. pulicaria had mtDNA ND5 haplotypes of the European D. pulicaria lineage. Pyr were distinct from LLaP and HTM at the ND5 gene. By contrast, HTM shared two haplotypes with LLaP and one with Pyr. Principal Coordinate Analysis of the microsatellite data revealed clear genetic differentiation into three groups. HTM isolates were intermediate to Pyr and LLaP, congruent with a hybrid origin. Conclusion/Significance Inferred transitions to obligate parthenogenesis have occurred only in HTM, most likely as a result of hybridizations. In contrast to North American populations, these transitions do not appear to involve meiosis suppressor genes and have not been accompanied by polyploidy. The absence of obligate parthenogenesis in Pyr, an

  2. Geographic parthenogenesis and plant-enemy interactions in the common dandelion

    PubMed Central

    2013-01-01

    Background Many species with sexual and asexual variants show a pattern of geographic parthenogenesis where asexuals have broader and higher-latitude distribution than sexuals. Because sexual reproduction is often considered a costly evolutionary strategy that is advantageous in the face of selection by coevolving pests and pathogens, one possible explanation for geographic parthenogenesis is that populations at higher latitudes are exposed to fewer pests and pathogens. We tested this hypothesis in the common dandelion (Taraxacum officinale), a species with well-established geographic parthenogenesis, by screening prevalence and effects of several specialized pests and pathogens in natural dandelion populations. Results We did a population survey of 18 dandelion populations along a geographic transect that ranged from the area where sexual and asexual dandelions co-occur northward into the area where only asexuals occur. In addition we used four southern and four northern populations in a 8x8 cross-inoculation greenhouse experiment in which plants were exposed experimentally to each other’s natural field soil microbial communities. The cross-inoculation experiment indicated a higher pathogenicity of soil microbial communities from the southern, mostly sexual, populations compared to soil microbial communities from the northern asexual populations. Northern dandelion populations also showed reduced infestation by a specialized seed-eating weevil. A similar trend of reduced rust fungus infection in northern populations was observed but this trend was not statistically significant. Conclusions The prevalence of pests and pathogens decreased along the south-to-north axis of geographic parthenogenesis. This highlights the potential of biotic interactions in shaping patterns of geographic parthenogenesis. PMID:23356700

  3. Asexuality alone does not explain the success of clonal forms in insects with geographical parthenogenesis.

    PubMed

    Lundmark, Magnus; Saura, Anssi

    2006-12-01

    Asexual forms of invertebrates are relatively common. They are often more successful than their sexual progenitors. Especially in insects, the pattern called geographical parthenogenesis shows that asexuality is important in speciation and ecological adaptation. In geographical parthenogenesis the clones have a wider distribution than the sexual forms they originate from. This indicates that they have a broader niche they may utilize successfully. The cause of this apparent success is, however, hard to come by as the term asexuality covers separate phenomena that are hard to disentangle from the mode of reproduction itself. Asexual insects are often polyploid, of hybrid origin, or both and these phenomena have been argued to explain the distribution patterns better than clonality. In this study we survey the literature on arthropods with geographical parthenogenesis in an attempt to clarify what evidence there is for the different phenomena explaining the success of the clonal forms. We focus on the few species where knowledge of distribution of different ploidy levels allows for a distinction of contributions from different phenomena to be made. Our survey support that asexuality is not the only factor underlying the success of all asexuals. Evidence about the importance of a hybrid origin of the clones is found to be meagre as the origin of clones is unknown in the majority of cases. Asexuality, hybridity and polyploidy are intertwined phenomena that each and all may contribute to the success of clonal taxa. Polyploidy, however, emerges as the most parsimonious factor explaining the success of these asexual invertebrate taxa.

  4. Patterns of recurrent evolution and geographic parthenogenesis within apomictic polyploid Easter daises (Townsendia hookeri).

    PubMed

    Thompson, Stacey Lee; Whitton, Jeannette

    2006-10-01

    Geographic patterns of parthenogenesis and the number of transitions from sexual diploidy to asexual (apomictic) autopolyploidy were examined for 40 populations of the Easter daisy, Townsendia hookeri. Analyses of pollen diameter and stainability characterized 15 sexual diploid and 25 apomictic polyploid populations from throughout the plant's western North American range. Sexual diploids were restricted to two Wisconsin refugia: Colorado/Wyoming, south of the ice sheets, and northern Yukon/Beringia. Chloroplast DNA sequencing uncovered 17 polymorphisms within the ndhF gene and trnK intron, yielding 10 haplotypes. Phylogenetic analyses indicated that five exclusively polyploid haplotypes were derived from four haplotypes that are shared among ploidies, conservatively inferring a minimum of four origins of apomictic polyploidy. Three of these apomictic polyploid origins were derived from southern sexual diploids, while the fourth origin was derived from northern sexual diploids. Analyses of regional diversity were suggestive of a formerly broad distribution for sexual diploids that has become subsequently fragmented, possibly due to the last round of glaciation. As sexual diploids were exclusively found north and south of the glacial maximum, while formerly glaciated areas were exclusively inhabited by asexual polyploids derived from both northern and southern sexual lineages, it is more likely that patterns of glaciation, as opposed to a particular latitudinal trend, played a causal role in the establishment of the observed pattern of geographic parthenogenesis in Easter daisies. PMID:16968277

  5. Cytotype stability, facultative apomixis and geographical parthenogenesis in Ranunculus kuepferi (Ranunculaceae)

    PubMed Central

    Cosendai, Anne-Caroline; Hörandl, Elvira

    2010-01-01

    Background and Aims Asexual organisms are more widespread in previously glaciated areas than their sexual relatives (‘geographical parthenogenesis’). In plants, this pattern is probably dependent on reproductive isolation and stability of cytotypes within their respective distribution areas. Both partial apomixis and introgressive hybridization potentially destabilize the spatial separation of sexual and apomictic populations. The wide distribution of apomicts may be further enhanced by uniparental reproduction which is advantageous for colonization. These factors are studied in the alpine species Ranunculus kuepferi. Methods Geographical distribution, diversity and mode of reproduction of cytotypes were assessed using flow cytometry and flow cytometric seed screening on samples from 59 natural populations of Ranunculus kuepferi. Seed set of cytotypes was compared in the wild. Key Results Diploid sexuals are confined to the south-western parts of the Alps, while tetraploid apomicts dominate in previously glaciated and in geographically isolated areas despite a significantly lower fertility. Other cytotypes (3x, 5x and 6x) occur mainly in the sympatric zone, but without establishing populations. The tetraploids are predominantly apomictic, but also show a partial apomixis via an uncoupling of apomeiosis and parthenogenesis in the seed material. Both pseudogamy and autonomous endosperm formation are observed which may enhance uniparental reproduction. Conclusions Diploids occupy a glacial relic area and resist introgression of apomixis, probably because of a significantly higher seed set. Among the polyploids, only apomictic tetraploids form stable populations; the other cytotypes arising from partial apomixis fail to establish, probably because of minority cytotype disadvantages. Tetraploid apomicts colonize previously devastated and also distant areas via long-distance dispersal, confirming Baker's law of an advantage of uniparental reproduction. It is

  6. Geographical parthenogenesis and population genetic structure in the alpine species Ranunculus kuepferi (Ranunculaceae).

    PubMed

    Cosendai, A-C; Wagner, J; Ladinig, U; Rosche, C; Hörandl, E

    2013-06-01

    Geographical parthenogenesis describes the enigmatic phenomenon that asexual organisms have larger distribution areas than their sexual relatives, especially in previously glaciated areas. Classical models suggest temporary advantages to asexuality in colonization scenarios because of uniparental reproduction and clonality. We analyzed population genetic structure and self-fertility of the plant species Ranunculus kuepferi on 59 populations from the whole distribution area (European Alps, Apennines and Corsica). Amplified fragment length polymorphisms (AFLPs) and five microsatellite loci revealed individual genotypes for all populations and mostly insignificant differences between diploid sexuals and tetraploid apomicts in all measures of genetic diversity. Low frequencies of private AFLP fragments/simple sequence repeat alleles, and character incompatibility analyses suggest that facultative recombination explains best the unexpectedly high genotypic diversity of apomicts. STRUCTURE analyses using AFLPs revealed a higher number of partitions and a stronger geographical subdivision for diploids than for tetraploids, which contradicts expectations of standard gene flow models, but indicates a reduction of genetic structure in asexuals. Apomictic populations exhibited high admixture near the sexual area, but appeared rather uniform in remote areas. Bagging experiments and analyses of pollen tube growth confirmed self-fertility for pollen-dependent apomicts, but self-sterility for diploid sexuals. Facultative apomixis combines advantages of both modes of reproduction: uniparental reproduction allows for rapid colonization of remote areas, whereas facultative sexuality and polyploidy maintains genetic diversity within apomictic populations. The density dependence of outcrossing limits range expansions of sexual populations.

  7. Cytogenetic and molecular evidence suggest multiple origins and geographical parthenogenesis in Nothoscordum gracile (Alliaceae)

    PubMed Central

    Souza, Luiz Gustavo Rodrigues; Crosa, Orfeo; Speranza, Pablo; Guerra, Marcelo

    2012-01-01

    Background and Aims Nothoscordum gracile is an apomitic tetraploid widely distributed throughout the Americas and naturalized in many temperate regions of other continents. It has been suggested to form a species complex with sexual and apomictic N. nudicaule and N. macrostemon. Tetraploids of these species also share a structurally heterozygous chromosome complement 2n = 19 (13M + 6A). In this work, the origin of N. gracile and its relationships with its related species was investigated based on cytological and molecular data. Methods Cytogenetic analyses were based on meiotic behaviour, CMA bands, localization of 5S and 45S rDNA sites, and genomic in situ hybridization (GISH). Nuclear ITS and plastidial trnL-trnF sequences were also obtained for most individuals. Key Results Proximal CMA bands were observed in the long arms of all acrocentrics of 2x and 4x N. macrostemon but not in diploid and some tetraploid cytotypes of N. nudicaule. Samples of N. gracile showed a variable number of CMA bands in the long arms of acrocentrics. Analysis of ITS sequences, dot-blot, GISH, and 5S and 45S rDNA sites, revealed no differentiation among the three species. The trnL-trnF cpDNA fragment showed variation with a trend to geographical structuring irrespective of morphospecies and fully congruent with karyotype variation. Conclusions The 2n = 19 karyotype was probably formed by a centric fusion event occurring in N. nudicaule and later transmitted to tetraploid cytotypes of N. macrostemon. Diploids of N. nudicaule and N. macrostemon appeared as consistent recently diverged species, whereas tetraploid apomicts seem to constitute an assemblage of polyploid hybrids originating from multiple independent hybridization events between them, part of which are morphologically recognizable as N. gracile. PMID:22362660

  8. Evaluation of elevated ploidy and asexual reproduction as alternative explanations for geographic parthenogenesis in Eucypris virens ostracods.

    PubMed

    Adolfsson, Sofia; Michalakis, Yannis; Paczesniak, Dorota; Bode, Saskia N S; Butlin, Roger K; Lamatsch, Dunja K; Martins, Maria J F; Schmit, Olivier; Vandekerkhove, Jochen; Jokela, Jukka

    2010-04-01

    Transitions from sexual to asexual reproduction are often coupled with elevations in ploidy. As a consequence, the importance of ploidy per se for the maintenance and spread of asexual populations is unclear. To examine the effects of ploidy and asexual reproduction as independent determinants of the success of asexual lineages, we sampled diploid sexual, diploid asexual, and triploid asexual Eucypris virens ostracods across a European wide range. Applying nuclear and mitochondrial markers, we found that E. virens consists of genetically highly differentiated diploid sexual populations, to the extent that these sexual clades could be considered as cryptic species. All sexual populations were found in southern Europe and North Africa and we found that both diploid asexual and triploid asexual lineages have originated multiple times from several sexual lineages. Therefore, the asexual lineages show a wide variety of genetic backgrounds and very strong population genetic structure across the wide geographic range. Finally, we found that triploid, but not diploid, asexual clones dominate habitats in northern Europe. The limited distribution of diploid asexual lineages, despite their shared ancestry with triploid asexual lineages, strongly suggests that the wider geographic distribution of triploids is due to elevated ploidy rather than to asexuality.

  9. Parthenogenesis in Komodo dragons.

    PubMed

    Watts, Phillip C; Buley, Kevin R; Sanderson, Stephanie; Boardman, Wayne; Ciofi, Claudio; Gibson, Richard

    2006-12-21

    Parthenogenesis, the production of offspring without fertilization by a male, is rare in vertebrate species, which usually reproduce after fusion of male and female gametes. Here we use genetic fingerprinting to identify parthenogenetic offspring produced by two female Komodo dragons (Varanus komodoensis) that had been kept at separate institutions and isolated from males; one of these females subsequently produced additional offspring sexually. This reproductive plasticity indicates that female Komodo dragons may switch between asexual and sexual reproduction, depending on the availability of a mate--a finding that has implications for the breeding of this threatened species in captivity. Most zoos keep only females, with males being moved between zoos for mating, but perhaps they should be kept together to avoid triggering parthenogenesis and thereby decreasing genetic diversity.

  10. Photographic Mosaics and Geographic Generalizations: A Perceptual Approach to Geographic Education

    ERIC Educational Resources Information Center

    Castner, Henry W.

    2003-01-01

    If vision can be considered the basis of geographic inquiry, then it must involve looking with discrimination--the ability to discern clues in our surroundings that speak to spatial processes or patterns in all aspects of geography--physical, cultural, economic, and so on. Geographic thinking also involves making spatial generalizations. We do…

  11. Large variation in mitochondrial DNA of sexual and parthenogenetic Dahlica triquetrella (Lepidoptera: Psychidae) shows multiple origins of parthenogenesis

    PubMed Central

    2013-01-01

    Background Obligate parthenogenesis is relatively rare in animals. Still, in some groups it is quite common and has evolved and persisted multiple times. These groups may provide important clues to help solve the ‘paradox of sex’. Several species in the Psychidae (Lepidoptera) have obligate parthenogenesis. Dahlica triquetrella is one of those species where multiple transitions to parthenogenesis are postulated based on intensive cytological and behavioural studies. This has led to the hypothesis that multiple transitions from sexuals to diploid parthenogens occurred during and after the last glacial period, followed by transitions from parthenogenetic diploids to parthenogenetic tetraploids. Our study is the first to test these hypotheses using a molecular phylogeny based on mtDNA from multiple sexual and parthenogenetic populations from a wide geographic range. Results Parthenogenetic (and sexual) D. triquetrella are not monophyletic, and considerable sequence variation is present suggesting multiple transitions to parthenogenesis. However, we could not establish ancestral sexual haplotypes from our dataset. Our data suggest that some parthenogenetic clades have evolved, indicating origins of parthenogenesis before the last glacial period. Conclusions Multiple transitions to parthenogenesis have taken place in Dahlica triquetrella, confirming previous hypotheses. The number of different parthenogenetic clades, haplotypes and their apparent evolutionary age, clearly show that parthenogenesis has been a very successful reproductive strategy in this species over a long period. PMID:23622052

  12. What does the geography of parthenogenesis teach us about sex?

    PubMed

    Tilquin, Anaïs; Kokko, Hanna

    2016-10-19

    Theory predicts that sexual reproduction is difficult to maintain if asexuality is an option, yet sex is very common. To understand why, it is important to pay attention to repeatably occurring conditions that favour transitions to, or persistence of, asexuality. Geographic parthenogenesis is a term that has been applied to describe a large variety of patterns where sexual and related asexual forms differ in their geographic distribution. Often asexuality is stated to occur in a habitat that is, in some sense, marginal, but the interpretation differs across studies: parthenogens might not only predominate near the margin of the sexuals' distribution, but might also extend far beyond the sexual range; they may be disproportionately found in newly colonizable areas (e.g. areas previously glaciated), or in habitats where abiotic selection pressures are relatively stronger than biotic ones (e.g. cold, dry). Here, we review the various patterns proposed in the literature, the hypotheses put forward to explain them, and the assumptions they rely on. Surprisingly, few mathematical models consider geographic parthenogenesis as their focal question, but all models for the evolution of sex could be evaluated in this framework if the (often ecological) causal factors vary predictably with geography. We also recommend broadening the taxa studied beyond the traditional favourites.This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'. PMID:27619701

  13. What does the geography of parthenogenesis teach us about sex?

    PubMed

    Tilquin, Anaïs; Kokko, Hanna

    2016-10-19

    Theory predicts that sexual reproduction is difficult to maintain if asexuality is an option, yet sex is very common. To understand why, it is important to pay attention to repeatably occurring conditions that favour transitions to, or persistence of, asexuality. Geographic parthenogenesis is a term that has been applied to describe a large variety of patterns where sexual and related asexual forms differ in their geographic distribution. Often asexuality is stated to occur in a habitat that is, in some sense, marginal, but the interpretation differs across studies: parthenogens might not only predominate near the margin of the sexuals' distribution, but might also extend far beyond the sexual range; they may be disproportionately found in newly colonizable areas (e.g. areas previously glaciated), or in habitats where abiotic selection pressures are relatively stronger than biotic ones (e.g. cold, dry). Here, we review the various patterns proposed in the literature, the hypotheses put forward to explain them, and the assumptions they rely on. Surprisingly, few mathematical models consider geographic parthenogenesis as their focal question, but all models for the evolution of sex could be evaluated in this framework if the (often ecological) causal factors vary predictably with geography. We also recommend broadening the taxa studied beyond the traditional favourites.This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'.

  14. Facultative parthenogenesis discovered in wild vertebrates

    PubMed Central

    Booth, Warren; Smith, Charles F.; Eskridge, Pamela H.; Hoss, Shannon K.; Mendelson, Joseph R.; Schuett, Gordon W.

    2012-01-01

    Facultative parthenogenesis (FP)—asexual reproduction by bisexual species—has been documented in a variety of multi-cellular organisms but only recently in snakes, varanid lizards, birds and sharks. Unlike the approximately 80 taxa of unisexual reptiles, amphibians and fishes that exist in nature, FP has yet to be documented in the wild. Based on captive documentation, it appears that FP is widespread in squamate reptiles (snakes, lizards and amphisbaenians), and its occurrence in nature seems inevitable, yet the task of detecting FP in wild individuals has been deemed formidable. Here we show, using microsatellite DNA genotyping and litter characteristics, the first cases of FP in wild-collected pregnant females and their offspring of two closely related species of North American pitviper snakes—the copperhead (Agkistrodon contortrix) and cottonmouth (Agkistrodon piscivorus). Our findings support the view that non-hybrid origins of parthenogenesis, such as FP, are more common in squamates than previously thought. With this confirmation, FP can no longer be viewed as a rare curiosity outside the mainstream of vertebrate evolution. Future research on FP in squamate reptiles related to proximate control of induction, reproductive competence of parthenogens and population genetics modelling is warranted. PMID:22977071

  15. Facultative parthenogenesis discovered in wild vertebrates.

    PubMed

    Booth, Warren; Smith, Charles F; Eskridge, Pamela H; Hoss, Shannon K; Mendelson, Joseph R; Schuett, Gordon W

    2012-12-23

    Facultative parthenogenesis (FP)-asexual reproduction by bisexual species-has been documented in a variety of multi-cellular organisms but only recently in snakes, varanid lizards, birds and sharks. Unlike the approximately 80 taxa of unisexual reptiles, amphibians and fishes that exist in nature, FP has yet to be documented in the wild. Based on captive documentation, it appears that FP is widespread in squamate reptiles (snakes, lizards and amphisbaenians), and its occurrence in nature seems inevitable, yet the task of detecting FP in wild individuals has been deemed formidable. Here we show, using microsatellite DNA genotyping and litter characteristics, the first cases of FP in wild-collected pregnant females and their offspring of two closely related species of North American pitviper snakes-the copperhead (Agkistrodon contortrix) and cottonmouth (Agkistrodon piscivorus). Our findings support the view that non-hybrid origins of parthenogenesis, such as FP, are more common in squamates than previously thought. With this confirmation, FP can no longer be viewed as a rare curiosity outside the mainstream of vertebrate evolution. Future research on FP in squamate reptiles related to proximate control of induction, reproductive competence of parthenogens and population genetics modelling is warranted. PMID:22977071

  16. Facultative parthenogenesis in vertebrates: reproductive error or chance?

    PubMed

    Lampert, K P

    2008-01-01

    Parthenogenesis, the development of an embryo from a female gamete without any contribution of a male gamete, is very rare in vertebrates. Parthenogenetically reproducing species have, so far, only been found in the Squamate reptiles (lizards and snakes). Facultative parthenogenesis, switching between sexual and clonal reproduction, although quite common in invertebrates, e.g. Daphnia and aphids, seems to be even rarer in vertebrates. However, isolated cases of parthenogenetic development have been reported in all vertebrate groups. Facultative parthenogenesis in vertebrates has only been found in captive animals but might simply have been overlooked in natural populations. Even though its evolutionary impact is hard to determine and very likely varies depending on the ploidy restoration mechanisms and sex-determining mechanisms involved, facultative parthenogenesis is already discussed in conservation biology and medical research. To raise interest for facultative parthenogenesis especially in evolutionary biology, I summarize the current knowledge about facultative parthenogenesis in the different vertebrate groups, introduce mechanisms of diploid oocyte formation and discuss the genetic consequences and potential evolutionary impact of facultative parthenogenesis in vertebrates.

  17. Transcriptome Analysis of Thermal Parthenogenesis of the Domesticated Silkworm

    PubMed Central

    Du, Xin; Yao, Lusong; Li, Fengbo; Meng, Zhiqi

    2015-01-01

    Thermal induction of parthenogenesis (also known as thermal parthenogenesis) in silkworms is an important technique that has been used in artificial insemination, expansion of hybridization, transgenesis and sericultural production; however, the exact mechanisms of this induction remain unclear. This study aimed to investigate the gene expression profile in silkworms undergoing thermal parthenogenesis using RNA-seq analysis. The transcriptome profiles indicated that in non-induced and induced eggs, the numbers of differentially expressed genes (DEGs) for the parthenogenetic line (PL) and amphigenetic line (AL) were 538 and 545, respectively, as determined by fold-change ≥ 2. Gene ontology (GO) analysis showed that DEGs between two lines were mainly involved in reproduction, formation of chorion, female gamete generation and cell development pathways. Upregulation of many chorion genes in AL suggests that the maturation rate of AL eggs was slower than PL eggs. Some DEGs related to reactive oxygen species removal, DNA repair and heat shock response were differentially expressed between the two lines, such as MPV-17, REV1 and HSP68. These results supported the view that a large fraction of genes are differentially expressed between PL and AL, which offers a new approach to identifying the molecular mechanism of silkworm thermal parthenogenesis. PMID:26274803

  18. Facultative parthenogenesis in the Ryukyu drywood termite Neotermes koshunensis.

    PubMed

    Kobayashi, Kazuya; Miyaguni, Yasushi

    2016-01-01

    Parthenogenesis is a relatively rare reproductive mode in nature compared to sex. In social insects, the evolution of parthenogenesis has a notable impact on their life histories. Some termites with parthenogenetic ability produce numerous non-dispersing supplementary queens asexually, whereas other castes are produced via sexual reproduction. This asexual queen succession (AQS) system is adaptive because hundreds of the asexual queens improve the reproductive potential of the colony and maintain the genetic diversity within the colony. However, the evolutionary process of the AQS system remains unclear because parthenogenetic species without this system are unknown. Here, we report facultative parthenogenesis in the drywood termite Neotermes koshunensis. Although the eggs produced by females isolated from males hatched, the hatching rate of those eggs was lower than that of the eggs produced by females kept with males. These parthenogenetic offspring inherited only the maternal alleles and showed high homozygosity, which indicates that the mechanism of ploidy restoration is terminal fusion. A previous study showed that most colonies of this species have a single queen or orphan; thus, the AQS system has not evolved despite their parthenogenetic ability. Further investigations of N. koshunensis will reveal how parthenogenesis evolved and its role in the insect societies. PMID:27464523

  19. Facultative parthenogenesis in the Ryukyu drywood termite Neotermes koshunensis

    PubMed Central

    Kobayashi, Kazuya; Miyaguni, Yasushi

    2016-01-01

    Parthenogenesis is a relatively rare reproductive mode in nature compared to sex. In social insects, the evolution of parthenogenesis has a notable impact on their life histories. Some termites with parthenogenetic ability produce numerous non-dispersing supplementary queens asexually, whereas other castes are produced via sexual reproduction. This asexual queen succession (AQS) system is adaptive because hundreds of the asexual queens improve the reproductive potential of the colony and maintain the genetic diversity within the colony. However, the evolutionary process of the AQS system remains unclear because parthenogenetic species without this system are unknown. Here, we report facultative parthenogenesis in the drywood termite Neotermes koshunensis. Although the eggs produced by females isolated from males hatched, the hatching rate of those eggs was lower than that of the eggs produced by females kept with males. These parthenogenetic offspring inherited only the maternal alleles and showed high homozygosity, which indicates that the mechanism of ploidy restoration is terminal fusion. A previous study showed that most colonies of this species have a single queen or orphan; thus, the AQS system has not evolved despite their parthenogenetic ability. Further investigations of N. koshunensis will reveal how parthenogenesis evolved and its role in the insect societies. PMID:27464523

  20. A high incidence of parthenogenesis in agricultural pests

    PubMed Central

    Hoffmann, Ary A; Tracy Reynolds, K; Nash, Michael A; Weeks, Andrew R

    2008-01-01

    Parthenogenetic species are assumed to represent evolutionary dead ends, yet parthenogenesis is common in some groups of invertebrates particularly in those found in relatively constant environments. This suggests that parthenogenetic reproduction might be common in pest invertebrates from uniform agricultural environments. Based on the evaluations of two databases from North America and Italy, we found that parthenogenetic species comprised 45 per cent (North America) or 48 per cent (Italy) of pest species derived from genera where parthenogenesis occurred, compared with an overall incidence of 10 per cent or 16 per cent in these genera. In establishing these patterns, we included only genera containing at least some member species that reproduced by parthenogenesis. The high incidence of parthenogenesis in pest species is spread across different families and several insect orders. Parthenogenetic reproduction may be favoured in agricultural environments when particular clones have a high fitness across multiple generations. Increasing the complexity and variability of agricultural environments represents one way of potentially controlling parthenogenetic pest species. PMID:18647717

  1. Facultative parthenogenesis in a critically endangered wild vertebrate.

    PubMed

    Fields, Andrew T; Feldheim, Kevin A; Poulakis, Gregg R; Chapman, Demian D

    2015-06-01

    Facultative parthenogenesis - the ability of sexually reproducing species to sometimes produce offspring asexually - is known from a wide range of ordinarily sexually reproducing vertebrates in captivity, including some birds, reptiles and sharks [1-3]. Despite this, free-living parthenogens have never been observed in any of these taxa in the wild, although two free-living snakes were recently discovered each gestating a single parthenogen - one copperhead (Agkistrodon contortrix) and one cottonmouth (Agkistrodon piscivorus) [1]. Vertebrate parthenogens are characterized as being of the homogametic sex (e.g., females in sharks, males in birds) and by having elevated homozygosity compared to their mother [1-3], which may reduce their viability [4]. Although it is unknown if either of the parthenogenetic snakes would have been carried to term or survived in the wild, facultative parthenogenesis might have adaptive significance [1]. If this is true, it is reasonable to hypothesize that parthenogenesis would be found most often at low population density, when females risk reproductive failure because finding mates is difficult [5]. Here, we document the first examples of viable parthenogens living in a normally sexually reproducing wild vertebrate, the smalltooth sawfish (Pristis pectinata). We also provide a simple approach to screen any microsatellite DNA database for parthenogens, which will enable hypothesis-driven research on the significance of vertebrate parthenogenesis in the wild. PMID:26035783

  2. Natural interspecific and intraspecific horizontal transfer of parthenogenesis-inducing Wolbachia in Trichogramma wasps.

    PubMed Central

    Huigens, M. E.; de Almeida, R. P.; Boons, P. A. H.; Luck, R. F.; Stouthamer, R.

    2004-01-01

    The intracellular bacterium Wolbachia is one of the most common symbionts in arthropods and, because of its manipulative effects on host reproduction, is assumed to be an important factor in several evolutionary processes. These bacteria are mainly vertically transmitted from mother to daughter through the egg cytoplasm, and horizontal transmission is generally assumed to be rare. Here, we show natural inter- and intraspecific horizontal transfer of parthenogenesis-inducing Wolbachia between parasitoid wasps of the genus Trichogramma. Horizontal transfer was observed when infected and uninfected larvae shared the same host egg. This is the first report, to our knowledge, on interspecific horizontal transfer of Wolbachia between closely related sympatric species. Some originally uninfected immature wasps acquired Wolbachia while inside the host egg, but not all of these newly infected females exhibited the parthenogenesis phenotype. In general, intraspecific horizontal transfer was more successful than interspecific transfer. Wolbachia underwent vertical transmission in the new species but the infection tended to be lost within several generations. Our results have important implications for understanding the evolution of Wolbachia-host associations. PMID:15129961

  3. Horizontal transmission of parthenogenesis-inducing microbes in Trichogramma wasps.

    PubMed Central

    Schilthuizen, M; Stouthamer, R

    1997-01-01

    Complete parthenogenesis (thelytoky) in species of the parasitic wasp Trichogramma is usually caused by the cytoplasmically inherited bacterium Wolbachia. This symbiont induces gamete duplication, which, in these haplodiploid organisms, results in all-female broods. Antibiotic treatment "cures' this condition, restoring normal sexual reproduction. Phylogenetic analysis of Wolbachia has shown that, in contrast with the strains in other host organisms (where the symbiont also induces different reproductive alterations), those in Trichogramma form a monophyletic group. This might be an indication of symbiont-host cocladogenesis. To test this, we performed comparative molecular phylogenetics on 20 parthenogenetic Trichogramma cultures and their Wolbachiae. We conclude that there is, in fact, little evidence for cocladogenesis. Instead, the phylogenetic distribution of the symbionts appears to result from occasional horizontal transmission, which probably takes place inside the hosts of Trichogramma parasitoids (usually lepidopteran eggs). This study therefore suggests that parthenogenesis is not only curable, it can sometimes be contagious also. PMID:9107051

  4. Androgenesis, gynogenesis, and parthenogenesis haploids in cucurbit species.

    PubMed

    Dong, Yan-Qi; Zhao, Wei-Xing; Li, Xiao-Hui; Liu, Xi-Cun; Gao, Ning-Ning; Huang, Jin-Hua; Wang, Wen-Ying; Xu, Xiao-Li; Tang, Zhen-Hai

    2016-10-01

    Haploids and doubled haploids are critical components of plant breeding. This review is focused on studies on haploids and double haploids inducted in cucurbits through in vitro pollination with irradiated pollen, unfertilized ovule/ovary culture, and anther/microspore culture during the last 30 years, as well as comprehensive analysis of the main factors of each process and comparison between chromosome doubling and ploidy identification methods, with special focus on the application of double haploids in plant breeding and genetics. This review identifies existing problems affecting the efficiency of androgenesis, gynogenesis, and parthenogenesis in cucurbit species. Donor plant genotypes and surrounding environments, developmental stages of explants, culture media, stress factors, and chromosome doubling and ploidy identification are compared at length and discussed as methodologies and protocols for androgenesis, gynogenesis, and parthenogenesis in haploid and double haploid production technologies. PMID:27379846

  5. Annually recurring parthenogenesis in a zebra shark Stegostoma fasciatum.

    PubMed

    Robinson, D P; Baverstock, W; Al-Jaru, A; Hyland, K; Khazanehdari, K A

    2011-11-01

    A zebra shark, Stegostoma fasciatum, held in captivity at the Burj Al Arab aquarium, produced embryos and pups in the absence of a male. A total of 15 pups were produced from eggs laid within the aquarium over a period of four consecutive years commencing 2007. Parthenogenesis was confirmed through DNA analysis for three pups sampled during the first two consecutive egg cycles and is presumed to be the method of reproduction responsible thereafter. PMID:22026614

  6. Comparative Genomics of a Parthenogenesis-Inducing Wolbachia Symbiont

    PubMed Central

    Lindsey, Amelia R. I.; Werren, John H.; Richards, Stephen; Stouthamer, Richard

    2016-01-01

    Wolbachia is an intracellular symbiont of invertebrates responsible for inducing a wide variety of phenotypes in its host. These host-Wolbachia relationships span the continuum from reproductive parasitism to obligate mutualism, and provide a unique system to study genomic changes associated with the evolution of symbiosis. We present the genome sequence from a parthenogenesis-inducing Wolbachia strain (wTpre) infecting the minute parasitoid wasp Trichogramma pretiosum. The wTpre genome is the most complete parthenogenesis-inducing Wolbachia genome available to date. We used comparative genomics across 16 Wolbachia strains, representing five supergroups, to identify a core Wolbachia genome of 496 sets of orthologous genes. Only 14 of these sets are unique to Wolbachia when compared to other bacteria from the Rickettsiales. We show that the B supergroup of Wolbachia, of which wTpre is a member, contains a significantly higher number of ankyrin repeat-containing genes than other supergroups. In the wTpre genome, there is evidence for truncation of the protein coding sequences in 20% of ORFs, mostly as a result of frameshift mutations. The wTpre strain represents a conversion from cytoplasmic incompatibility to a parthenogenesis-inducing lifestyle, and is required for reproduction in the Trichogramma host it infects. We hypothesize that the large number of coding frame truncations has accompanied the change in reproductive mode of the wTpre strain. PMID:27194801

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2013-01-01

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

  9. The intriguing complexity of parthenogenesis inheritance in Pilosella rubra (Asteraceae, Lactuceae).

    PubMed

    Rosenbaumová, Radka; Krahulcová, Anna; Krahulec, František

    2012-09-01

    Neither the genetic basis nor the inheritance of apomixis is fully understood in plants. The present study is focused on the inheritance of parthenogenesis, one of the basic elements of apomixis, in Pilosella (Asteraceae). A complex pattern of inheritance was recorded in the segregating F(1) progeny recovered from reciprocal crosses between the facultatively apomictic hexaploid P. rubra and the sexual tetraploid P. officinarum. Although both female and male reduced gametes of P. rubra transmitted parthenogenesis at the same rate in the reciprocal crosses, the resulting segregating F(1) progeny inherited parthenogenesis at different rates. The actual transmission rates of parthenogenesis were significantly correlated with the mode of origin of the respective F(1) progeny class. The inheritance of parthenogenesis was significantly reduced in F(1) n + n hybrid progeny from the cross where parthenogenesis was transmitted by female gametes. In F(1) n + 0 polyhaploid progeny from the same cross, however, the transmission rate of parthenogenesis was high; all fertile polyhaploids were parthenogenetic. It appeared that reduced female gametes transmitting parthenogenesis preferentially developed parthenogenetically and only rarely were fertilized in P. rubra. The fact that the determinant for parthenogenesis acts gametophytically in Pilosella and the precocious embryogenesis in parthenogenesis-transmitting megagametophytes was suggested as the most probable explanations for this observation. Furthermore, we observed the different expression of complete apomixis in the non-segregating F(1) 2n + n hybrids as compared to their apomictic maternal parent P. rubra. We suggest that this difference is a result of unspecified interactions between the parental genomes.

  10. Positive feedback in the transition from sexual reproduction to parthenogenesis.

    PubMed

    Schwander, Tanja; Vuilleumier, Séverine; Dubman, Janie; Crespi, Bernard J

    2010-05-01

    Understanding how new phenotypes evolve is challenging because intermediate stages in transitions from ancestral to derived phenotypes often remain elusive. Here we describe and evaluate a new mechanism facilitating the transition from sexual reproduction to parthenogenesis. In many sexually reproducing species, a small proportion of unfertilized eggs can hatch spontaneously ('tychoparthenogenesis') and develop into females. Using an analytical model, we show that if females are mate-limited, tychoparthenogenesis can result in the loss of males through a positive feedback mechanism whereby tychoparthenogenesis generates female-biased sex ratios and increasing mate limitation. As a result, the strength of selection for tychoparthenogenesis increases in concert with the proportion of tychoparthenogenetic offspring in the sexual population. We then tested the hypothesis that mate limitation selects for tychoparthenogenesis and generates female-biased sex ratios, using data from natural populations of sexually reproducing Timema stick insects. Across 41 populations, both the tychoparthenogenesis rates and the proportions of females increased exponentially as the density of individuals decreased, consistent with the idea that low densities of individuals result in mate limitation and selection for reproductive insurance through tychoparthenogenesis. Our model and data from Timema populations provide evidence for a simple mechanism through which parthenogenesis can evolve rapidly in a sexual population.

  11. Parthenogenesis in a Brazilian rainbow boa (Epicrates cenchria cenchria).

    PubMed

    Kinney, Matthew E; Wack, Raymund F; Grahn, Robert A; Lyons, Leslie

    2013-03-01

    A 22-year-old captive Brazilian rainbow boa (Epicrates cenchria cenchria) gave birth to four offspring after being housed with a vasectomized male. Sexual reproduction as a result of failed prior vasectomy, recanalization of the vas deferens, or prolonged sperm storage was ruled out using the clinical history, histopathology, and gross necropsy. Short tandem repeat (STR) DNA markers were genotyped in the male, female, and four offspring. None of the offspring possessed a diagnostic STR allele present in the potential sire. In addition, all offspring were homozygous at each STR locus evaluated, supporting parthenogenetic reproduction. This is the first report of parthenogenesis in a Brazilian rainbow boa and has implications for the conservation of reptiles maintained in captive breeding programs.

  12. Geographically weighted regression as a generalized Wombling to detect barriers to gene flow.

    PubMed

    Diniz-Filho, José Alexandre Felizola; Soares, Thannya Nascimento; de Campos Telles, Mariana Pires

    2016-08-01

    Barriers to gene flow play an important role in structuring populations, especially in human-modified landscapes, and several methods have been proposed to detect such barriers. However, most applications of these methods require a relative large number of individuals or populations distributed in space, connected by vertices from Delaunay or Gabriel networks. Here we show, using both simulated and empirical data, a new application of geographically weighted regression (GWR) to detect such barriers, modeling the genetic variation as a "local" linear function of geographic coordinates (latitude and longitude). In the GWR, standard regression statistics, such as R(2) and slopes, are estimated for each sampling unit and thus are mapped. Peaks in these local statistics are then expected close to the barriers if genetic discontinuities exist, capturing a higher rate of population differentiation among neighboring populations. Isolation-by-Distance simulations on a longitudinally warped lattice revealed that higher local slopes from GWR coincide with the barrier detected with Monmonier algorithm. Even with a relatively small effect of the barrier, the power of local GWR in detecting the east-west barriers was higher than 95 %. We also analyzed empirical data of genetic differentiation among tree populations of Dipteryx alata and Eugenia dysenterica Brazilian Cerrado. GWR was applied to the principal coordinate of the pairwise FST matrix based on microsatellite loci. In both simulated and empirical data, the GWR results were consistent with discontinuities detected by Monmonier algorithm, as well as with previous explanations for the spatial patterns of genetic differentiation for the two species. Our analyses reveal how this new application of GWR can viewed as a generalized Wombling in a continuous space and be a useful approach to detect barriers and discontinuities to gene flow. PMID:27353234

  13. Geographically weighted regression as a generalized Wombling to detect barriers to gene flow.

    PubMed

    Diniz-Filho, José Alexandre Felizola; Soares, Thannya Nascimento; de Campos Telles, Mariana Pires

    2016-08-01

    Barriers to gene flow play an important role in structuring populations, especially in human-modified landscapes, and several methods have been proposed to detect such barriers. However, most applications of these methods require a relative large number of individuals or populations distributed in space, connected by vertices from Delaunay or Gabriel networks. Here we show, using both simulated and empirical data, a new application of geographically weighted regression (GWR) to detect such barriers, modeling the genetic variation as a "local" linear function of geographic coordinates (latitude and longitude). In the GWR, standard regression statistics, such as R(2) and slopes, are estimated for each sampling unit and thus are mapped. Peaks in these local statistics are then expected close to the barriers if genetic discontinuities exist, capturing a higher rate of population differentiation among neighboring populations. Isolation-by-Distance simulations on a longitudinally warped lattice revealed that higher local slopes from GWR coincide with the barrier detected with Monmonier algorithm. Even with a relatively small effect of the barrier, the power of local GWR in detecting the east-west barriers was higher than 95 %. We also analyzed empirical data of genetic differentiation among tree populations of Dipteryx alata and Eugenia dysenterica Brazilian Cerrado. GWR was applied to the principal coordinate of the pairwise FST matrix based on microsatellite loci. In both simulated and empirical data, the GWR results were consistent with discontinuities detected by Monmonier algorithm, as well as with previous explanations for the spatial patterns of genetic differentiation for the two species. Our analyses reveal how this new application of GWR can viewed as a generalized Wombling in a continuous space and be a useful approach to detect barriers and discontinuities to gene flow.

  14. The Origin and Evolution of Parthenogenesis in Heteronotia Binoei (Gekkonidae): Evidence for Recent and Localized Origins of Widespread Clones

    PubMed Central

    Moritz, C.

    1991-01-01

    The parthenogenetic form of the gecko lizard species Heteronotia binoei has an unusually broad geographic range and high genetic diversity. Restriction enzyme analysis revealed two basic types of mitochondrial DNA (mtDNA) among the parthenogens. One type is restricted to western populations. The other type, analyzed in detail here, was widespread, being found in populations from central to western Australia. The diversity within this widespread type was low. The variation among parthenogens from central to western Australia was similar to that found within local populations of the sexual species that provided the mtDNA, and was an order of magnitude less than the differentiation shown between sexual populations across the same geographic distance. Phylogenetic analysis revealed that the widespread type of mtDNA in the parthenogens is most closely related to mtDNAs from western populations of the ``CA6'' sexual parent. These data suggest that these parthenogenetic clones arose recently within a small geographic area, most probably in Western Australia. The parthenogens must have spread rapidly to occupy much of the central and western Australian deserts. This rapid and extensive range expansion provides strong evidence that parthenogenesis can be a successful strategy for lizards in an environment with low and unpredictable rainfall. PMID:1682211

  15. Does a parthenogenesis-inducing Wolbachia induce vestigial cytoplasmic incompatibility?

    NASA Astrophysics Data System (ADS)

    Kraaijeveld, Ken; Reumer, Barbara M.; Mouton, Laurence; Kremer, Natacha; Vavre, Fabrice; van Alphen, Jacques J. M.

    2011-03-01

    Wolbachia is a maternally inherited bacterium that manipulates the reproduction of its host. Recent studies have shown that male-killing strains can induce cytoplasmic incompatibility (CI) when introgressed into a resistant host. Phylogenetic studies suggest that transitions between CI and other Wolbachia phenotypes have also occurred frequently, raising the possibility that latent CI may be widespread among Wolbachia. Here, we investigate whether a parthenogenesis-inducing Wolbachia strain can also induce CI. Parthenogenetic females of the parasitoid wasp Asobara japonica regularly produce a small number of males that may be either infected or not. Uninfected males were further obtained through removal of the Wolbachia using antibiotics and from a naturally uninfected strain. Uninfected females that had mated with infected males produced a slightly, but significantly more male-biased sex ratio than uninfected females that had mated with uninfected males. This effect was strongest in females that mated with males that had a relatively high Wolbachia titer. Quantitative PCR indicated that infected males did not show higher ratios of nuclear versus mitochondrial DNA content. Wolbachia therefore does not cause diploidization of cells in infected males. While these results are consistent with CI, other alternatives such as production of abnormal sperm by infected males cannot be completely ruled out. Overall, the effect was very small (9%), suggesting that if CI is involved it may have degenerated through the accumulation of mutations.

  16. The marbled crayfish as a paradigm for saltational speciation by autopolyploidy and parthenogenesis in animals

    PubMed Central

    Vogt, Günter; Falckenhayn, Cassandra; Schrimpf, Anne; Schmid, Katharina; Hanna, Katharina; Panteleit, Jörn; Helm, Mark; Schulz, Ralf; Lyko, Frank

    2015-01-01

    ABSTRACT The parthenogenetic all-female marbled crayfish is a novel research model and potent invader of freshwater ecosystems. It is a triploid descendant of the sexually reproducing slough crayfish, Procambarus fallax, but its taxonomic status has remained unsettled. By cross-breeding experiments and parentage analysis we show here that marbled crayfish and P. fallax are reproductively separated. Both crayfish copulate readily, suggesting that the reproductive barrier is set at the cytogenetic rather than the behavioural level. Analysis of complete mitochondrial genomes of marbled crayfish from laboratory lineages and wild populations demonstrates genetic identity and indicates a single origin. Flow cytometric comparison of DNA contents of haemocytes and analysis of nuclear microsatellite loci confirm triploidy and suggest autopolyploidisation as its cause. Global DNA methylation is significantly reduced in marbled crayfish implying the involvement of molecular epigenetic mechanisms in its origination. Morphologically, both crayfish are very similar but growth and fecundity are considerably larger in marbled crayfish, making it a different animal with superior fitness. These data and the high probability of a divergent future evolution of the marbled crayfish and P. fallax clusters suggest that marbled crayfish should be considered as an independent asexual species. Our findings also establish the P. fallax–marbled crayfish pair as a novel paradigm for rare chromosomal speciation by autopolyploidy and parthenogenesis in animals and for saltational evolution in general. PMID:26519519

  17. The marbled crayfish as a paradigm for saltational speciation by autopolyploidy and parthenogenesis in animals.

    PubMed

    Vogt, Günter; Falckenhayn, Cassandra; Schrimpf, Anne; Schmid, Katharina; Hanna, Katharina; Panteleit, Jörn; Helm, Mark; Schulz, Ralf; Lyko, Frank

    2015-01-01

    The parthenogenetic all-female marbled crayfish is a novel research model and potent invader of freshwater ecosystems. It is a triploid descendant of the sexually reproducing slough crayfish, Procambarus fallax, but its taxonomic status has remained unsettled. By cross-breeding experiments and parentage analysis we show here that marbled crayfish and P. fallax are reproductively separated. Both crayfish copulate readily, suggesting that the reproductive barrier is set at the cytogenetic rather than the behavioural level. Analysis of complete mitochondrial genomes of marbled crayfish from laboratory lineages and wild populations demonstrates genetic identity and indicates a single origin. Flow cytometric comparison of DNA contents of haemocytes and analysis of nuclear microsatellite loci confirm triploidy and suggest autopolyploidisation as its cause. Global DNA methylation is significantly reduced in marbled crayfish implying the involvement of molecular epigenetic mechanisms in its origination. Morphologically, both crayfish are very similar but growth and fecundity are considerably larger in marbled crayfish, making it a different animal with superior fitness. These data and the high probability of a divergent future evolution of the marbled crayfish and P. fallax clusters suggest that marbled crayfish should be considered as an independent asexual species. Our findings also establish the P. fallax-marbled crayfish pair as a novel paradigm for rare chromosomal speciation by autopolyploidy and parthenogenesis in animals and for saltational evolution in general.

  18. Meiosis genes in Daphnia pulex and the role of parthenogenesis in genome evolution

    PubMed Central

    Schurko, Andrew M; Logsdon, John M; Eads, Brian D

    2009-01-01

    Background Thousands of parthenogenetic animal species have been described and cytogenetic manifestations of this reproductive mode are well known. However, little is understood about the molecular determinants of parthenogenesis. The Daphnia pulex genome must contain the molecular machinery for different reproductive modes: sexual (both male and female meiosis) and parthenogenetic (which is either cyclical or obligate). This feature makes D. pulex an ideal model to investigate the genetic basis of parthenogenesis and its consequences for gene and genome evolution. Here we describe the inventory of meiotic genes and their expression patterns during meiotic and parthenogenetic reproduction to help address whether parthenogenesis uses existing meiotic and mitotic machinery, or whether novel processes may be involved. Results We report an inventory of 130 homologs representing over 40 genes encoding proteins with diverse roles in meiotic processes in the genome of D. pulex. Many genes involved in cell cycle regulation and sister chromatid cohesion are characterized by expansions in copy number. In contrast, most genes involved in DNA replication and homologous recombination are present as single copies. Notably, RECQ2 (which suppresses homologous recombination) is present in multiple copies while DMC1 is the only gene in our inventory that is absent in the Daphnia genome. Expression patterns for 44 gene copies were similar during meiosis versus parthenogenesis, although several genes displayed marked differences in expression level in germline and somatic tissues. Conclusion We propose that expansions in meiotic gene families in D. pulex may be associated with parthenogenesis. Taking into account our findings, we provide a mechanistic model of parthenogenesis, highlighting steps that must differ from meiosis including sister chromatid cohesion and kinetochore attachment. PMID:19383157

  19. Can artificial parthenogenesis sidestep ethical pitfalls in human therapeutic cloning? An historical perspective.

    PubMed

    Fangerau, H

    2005-12-01

    The aim of regenerative medicine is to reconstruct tissue that has been lost or pathologically altered. Therapeutic cloning seems to offer a method of achieving this aim; however, the ethical debate surrounding human therapeutic cloning is highly controversial. Artificial parthenogenesis-obtaining embryos from unfertilised eggs-seems to offer a way to sidestep these ethical pitfalls. Jacques Loeb (1859-1924), the founding father of artificial parthenogenesis, faced negative public opinion when he published his research in 1899. His research, the public's response to his findings, and his ethical foundations serve as an historical argument both for the communication of science and compromise in biological research.

  20. A general model for estimation of daily global solar radiation using air temperatures and site geographic parameters in Southwest China

    NASA Astrophysics Data System (ADS)

    Li, Mao-Fen; Fan, Li; Liu, Hong-Bin; Guo, Peng-Tao; Wu, Wei

    2013-01-01

    Estimation of daily global solar radiation (Rs) from routinely measured temperature data has been widely developed and used in many different areas of the world. However, many of them are site specific. It is assumed that a general model for estimating daily Rs using temperature variables and geographical parameters could be achieved within a climatic region. This paper made an attempt to develop a general model to estimate daily Rs using routinely measured temperature data (maximum (Tmax, °C) and minimum (Tmin, °C) temperatures) and site geographical parameters (latitude (La, °N), longitude (Ld, °E) and altitude (Alt, m)) for Guizhou and Sichuan basin of southwest China, which was classified into the hot summer and cold winter climate zone. Comparison analysis was carried out through statistics indicators such as root mean squared error of percentage (RMSE%), modeling efficiency (ME), coefficient of residual mass (CRM) and mean bias error (MBE). Site-dependent daily Rs estimating models were calibrated and validated using long-term observed weather data. A general formula was then obtained from site geographical parameters and the better fit site-dependent models with mean RMSE% of 38.68%, mean MBE of 0.381 MJ m-2 d-1, mean CRM of 0.04 and mean ME value of 0.713.

  1. A parthenogenesis gene of apomict origin elicits embryo formation from unfertilized eggs in a sexual plant.

    PubMed

    Conner, Joann A; Mookkan, Muruganantham; Huo, Heqiang; Chae, Keun; Ozias-Akins, Peggy

    2015-09-01

    Apomixis is a naturally occurring mode of asexual reproduction in flowering plants that results in seed formation without the involvement of meiosis or fertilization of the egg. Seeds formed on an apomictic plant contain offspring genetically identical to the maternal plant. Apomixis has significant potential for preserving hybrid vigor from one generation to the next in highly productive crop plant genotypes. Apomictic Pennisetum/Cenchrus species, members of the Poaceae (grass) family, reproduce by apospory. Apospory is characterized by apomeiosis, the formation of unreduced embryo sacs derived from nucellar cells of the ovary and, by parthenogenesis, the development of the unreduced egg into an embryo without fertilization. In Pennisetum squamulatum (L.) R.Br., apospory segregates as a single dominant locus, the apospory-specific genomic region (ASGR). In this study, we demonstrate that the PsASGR-BABY BOOM-like (PsASGR-BBML) gene is expressed in egg cells before fertilization and can induce parthenogenesis and the production of haploid offspring in transgenic sexual pearl millet. A reduction of PsASGR-BBML expression in apomictic F1 RNAi transgenic plants results in fewer visible parthenogenetic embryos and a reduction of embryo cell number compared with controls. Our results endorse a key role for PsASGR-BBML in parthenogenesis and a newly discovered role for a member of the BBM-like clade of APETALA 2 transcription factors. Induction of parthenogenesis by PsASGR-BBML will be valuable for installing parthenogenesis to synthesize apomixis in crops and will have further application for haploid induction to rapidly obtain homozygous lines for breeding. PMID:26305939

  2. A parthenogenesis gene of apomict origin elicits embryo formation from unfertilized eggs in a sexual plant

    PubMed Central

    Conner, Joann A.; Mookkan, Muruganantham; Huo, Heqiang; Chae, Keun; Ozias-Akins, Peggy

    2015-01-01

    Apomixis is a naturally occurring mode of asexual reproduction in flowering plants that results in seed formation without the involvement of meiosis or fertilization of the egg. Seeds formed on an apomictic plant contain offspring genetically identical to the maternal plant. Apomixis has significant potential for preserving hybrid vigor from one generation to the next in highly productive crop plant genotypes. Apomictic Pennisetum/Cenchrus species, members of the Poaceae (grass) family, reproduce by apospory. Apospory is characterized by apomeiosis, the formation of unreduced embryo sacs derived from nucellar cells of the ovary and, by parthenogenesis, the development of the unreduced egg into an embryo without fertilization. In Pennisetum squamulatum (L.) R.Br., apospory segregates as a single dominant locus, the apospory-specific genomic region (ASGR). In this study, we demonstrate that the PsASGR-BABY BOOM-like (PsASGR-BBML) gene is expressed in egg cells before fertilization and can induce parthenogenesis and the production of haploid offspring in transgenic sexual pearl millet. A reduction of PsASGR-BBML expression in apomictic F1 RNAi transgenic plants results in fewer visible parthenogenetic embryos and a reduction of embryo cell number compared with controls. Our results endorse a key role for PsASGR-BBML in parthenogenesis and a newly discovered role for a member of the BBM-like clade of APETALA 2 transcription factors. Induction of parthenogenesis by PsASGR-BBML will be valuable for installing parthenogenesis to synthesize apomixis in crops and will have further application for haploid induction to rapidly obtain homozygous lines for breeding. PMID:26305939

  3. A parthenogenesis gene of apomict origin elicits embryo formation from unfertilized eggs in a sexual plant.

    PubMed

    Conner, Joann A; Mookkan, Muruganantham; Huo, Heqiang; Chae, Keun; Ozias-Akins, Peggy

    2015-09-01

    Apomixis is a naturally occurring mode of asexual reproduction in flowering plants that results in seed formation without the involvement of meiosis or fertilization of the egg. Seeds formed on an apomictic plant contain offspring genetically identical to the maternal plant. Apomixis has significant potential for preserving hybrid vigor from one generation to the next in highly productive crop plant genotypes. Apomictic Pennisetum/Cenchrus species, members of the Poaceae (grass) family, reproduce by apospory. Apospory is characterized by apomeiosis, the formation of unreduced embryo sacs derived from nucellar cells of the ovary and, by parthenogenesis, the development of the unreduced egg into an embryo without fertilization. In Pennisetum squamulatum (L.) R.Br., apospory segregates as a single dominant locus, the apospory-specific genomic region (ASGR). In this study, we demonstrate that the PsASGR-BABY BOOM-like (PsASGR-BBML) gene is expressed in egg cells before fertilization and can induce parthenogenesis and the production of haploid offspring in transgenic sexual pearl millet. A reduction of PsASGR-BBML expression in apomictic F1 RNAi transgenic plants results in fewer visible parthenogenetic embryos and a reduction of embryo cell number compared with controls. Our results endorse a key role for PsASGR-BBML in parthenogenesis and a newly discovered role for a member of the BBM-like clade of APETALA 2 transcription factors. Induction of parthenogenesis by PsASGR-BBML will be valuable for installing parthenogenesis to synthesize apomixis in crops and will have further application for haploid induction to rapidly obtain homozygous lines for breeding.

  4. Genetic diversity and the phylogeography of parthenogenesis: comparing bisexual and thelytokous populations of Nemasoma varicorne (Diplopoda: Nemasomatidae) in Denmark.

    PubMed

    Jensen, Lone Hoy; Enghoff, Henrik; Frydenberg, Jane; Parker, E Davis

    2002-01-01

    The millipede, Nemasoma varicorne, represents a textbook example of geographic parthenogenesis with thelytokous populations being distributed north, east, south and west of the distribution of the bisexual ancestor in the deciduous forests of central Europe. We here describe variation in amplified fragment length polymorphisms (AFLP's) in sympatric bisexual and thelytokous populations of N. varicorne in Denmark and compare the relationships of Danish populations with animals from The Czech Republic, England and Poland. Thelytokes from Denmark, England and Poland form a monophyletic cluster that differs from bisexuals from Denmark and Czechia for about 30% of the fragments. A single clone is widely spread over Denmark (34 of 38 localities), with rare clones being detected at four other localities. The phylogenetic pattern implies strongly that thelytoky evolved prior to the post-glacial colonization of northern Europe. This further suggests that the two forms have interacted extensively during this colonization and that the thelytokes have been excluded from older forests by competition with the bisexual forms. Our results further suggest that the success of the thelytokous form, at least in Denmark, is not due to abundant clonal diversity as hypothesized by the frozen niche variation model.

  5. Do the Visual Complexity Algorithms Match the Generalization Process in Geographical Displays?

    NASA Astrophysics Data System (ADS)

    Brychtová, A.; Çöltekin, A.; Pászto, V.

    2016-06-01

    In this study, we first develop a hypothesis that existing quantitative visual complexity measures will overall reflect the level of cartographic generalization, and test this hypothesis. Specifically, to test our hypothesis, we first selected common geovisualization types (i.e., cartographic maps, hybrid maps, satellite images and shaded relief maps) and retrieved examples as provided by Google Maps, OpenStreetMap and SchweizMobil by swisstopo. Selected geovisualizations vary in cartographic design choices, scene contents and different levels of generalization. Following this, we applied one of Rosenholtz et al.'s (2007) visual clutter algorithms to obtain quantitative visual complexity scores for screenshots of the selected maps. We hypothesized that visual complexity should be constant across generalization levels, however, the algorithm suggested that the complexity of small-scale displays (less detailed) is higher than those of large-scale (high detail). We also observed vast differences in visual complexity among maps providers, which we attribute to their varying approaches towards the cartographic design and generalization process. Our efforts will contribute towards creating recommendations as to how the visual complexity algorithms could be optimized for cartographic products, and eventually be utilized as a part of the cartographic design process to assess the visual complexity.

  6. Parthenogenesis in mated Chinese Painted quail (Coturnix chinensis) hens decreases sperm-egg penetration and alters albumen characteristics.

    PubMed

    Santa Rosa, P; Parker, H M; Kiess, A S; McDaniel, C D

    2016-10-15

    Parthenogenesis, embryonic development without fertilization, resembles very early embryonic mortality in fertilized eggs. Also, parthenogenesis alters egg albumen characteristics in virgin Chinese Painted quail hens genetically selected for parthenogenesis (PV). When these PV hens are mated (PM), hatchability is reduced versus control mated (CM) hens that were not genetically selected for parthenogenesis. However, it is unclear if parthenogenesis, which occurs in PM hens, reduces hatchability due to infertility and altered albumen characteristics. Sperm-egg penetration (SEP) holes are indicative of true fertilization and may be useful in identifying if eggs from PM hens exhibit a decrease in fertility versus CM hens. Therefore, the objectives of this study were to determine if parthenogenesis in PM hens (1) decreases SEP, (2) alters albumen characteristics similar to parthenogenesis in eggs from PV hens, and (3) yields albumen characteristics similar to fertilized eggs containing early mortality. Daily, PV and PM eggs were collected, labeled, and incubated for 10 days, then broken out to determine the incidence of parthenogenesis and albumen characteristics. Also daily, fresh PM and CM quail eggs were macroscopically examined to determine if an egg was infertile with no embryonic development, parthenogenetic, or fertile. Each of these eggs was then microscopically examined for SEP. For both PV and PM incubated eggs, parthenogenesis decreased albumen pH, O2, and protein concentrations yet increased Ca(2+) and CO2 concentrations versus eggs with no development. For incubated PM eggs, albumen pH and O2 were lower, yet CO2 was higher for eggs containing parthenogens or early dead embryos versus infertile eggs. For SEP, fresh eggs classified as infertile or parthenogenetic from PM and CM hens had similar SEP holes but only one sixth as many SEP holes as eggs classified as fertilized. Eggs from CM hens had 3.5 times as many SEP holes as PM eggs. In conclusion

  7. SAS macro programs for geographically weighted generalized linear modeling with spatial point data: applications to health research.

    PubMed

    Chen, Vivian Yi-Ju; Yang, Tse-Chuan

    2012-08-01

    An increasing interest in exploring spatial non-stationarity has generated several specialized analytic software programs; however, few of these programs can be integrated natively into a well-developed statistical environment such as SAS. We not only developed a set of SAS macro programs to fill this gap, but also expanded the geographically weighted generalized linear modeling (GWGLM) by integrating the strengths of SAS into the GWGLM framework. Three features distinguish our work. First, the macro programs of this study provide more kernel weighting functions than the existing programs. Second, with our codes the users are able to better specify the bandwidth selection process compared to the capabilities of existing programs. Third, the development of the macro programs is fully embedded in the SAS environment, providing great potential for future exploration of complicated spatially varying coefficient models in other disciplines. We provided three empirical examples to illustrate the use of the SAS macro programs and demonstrated the advantages explained above.

  8. Thelytokous parthenogenesis by queens in the dacetine ant Pyramica membranifera (Hymenoptera: Formicidae)

    NASA Astrophysics Data System (ADS)

    Ito, Fuminori; Touyama, Yoshifumi; Gotoh, Ayako; Kitahiro, Shungo; Billen, Johan

    2010-08-01

    Thelytokous parthenogenesis in which diploid females are produced from unfertilized eggs, was recently reported for some ant species. Here, we document thelytokous reproduction by queens in the polygynous species Pyramica membranifera. Queens that emerged in the laboratory were kept with or without workers under laboratory conditions. Independent colony founding was successful for a few queens if prey was provided. All artificial colonies, which started with a newly emerged queen and workers produced new workers and some of the colonies also produced female sexuals. Some of the female sexuals shed their wings in the laboratory and started formation of new polygynous colonies. Workers had no ovaries and thus, were obligatorily sterile.

  9. Reproduction in Strongyloides (Nematoda): a life between sex and parthenogenesis.

    PubMed

    Streit, A

    2008-03-01

    Nematodes of the genus Strongyloides parasitize the small intestines of vertebrates. In addition to a parasitic life-cycle, which is generally considered to be parthenogenetic, Strongyloides can also have a facultative, free-living generation involving male and female worms. The purpose of the present article was to review the literature on the modes of reproduction, the routes of development in the two generations of Strongyloides, discuss the controversial opinions in the literature regarding these aspects and point to new opportunities for addressing key questions in relation to the biology of reproduction of members of the genus employing genetic and genomic tools. PMID:18076772

  10. Predators on rocky shores in the northern Atlantic: Can the results of local experiments be generalized on a geographical scale?

    NASA Astrophysics Data System (ADS)

    Ingólfsson, Agnar

    2009-07-01

    Experimental manipulations of invertebrate prey and predators on rocky shores have been done by many authors. In the northern Atlantic the predators involved are usually the green crab Carcinus maenas and/or the dogwhelk Nucella lapillus, and the prey species studied are acorn barnacles (balanid Cirripedia), mussels ( Mytilus spp.) and winkles ( Littorina spp.). Usually the predators are found to have a regulating "top-down" effect on the prey species. In Iceland the acorn barnacle Semibalanus balanoides, the blue mussel Mytilus edulis and the flat periwinkle Littorina obtusata (including to some extent Littorina mariae) are found on rocky shores all around Iceland in what would seem to be near-optimal physical conditions. The predators Carcinus maenas and Nucella lapillus, on the other hand, are relatively southern species that do not thrive on the colder coasts of Iceland. Thus general surveys of different coasts of Iceland would seem to offer opportunities to see whether the results of local experiments can be discerned on a geographical scale (hundreds of km). The roughly 4900 km of the rocky coastline in Iceland was in this study subdivided into four regions, I-IV, according to the commonness or presence of the two predators. With the hope of reducing compounding factors the surveys were confined to sheltered or semi-sheltered fucoid shores, which were further divided into Ascophyllum (more sheltered) and Fucus vesiculosus (less sheltered) shores. Estuaries or other low-salinity environments were avoided. The study was based on 761 stations distributed around the rocky coastline on these two types of shores. The results for barnacles and mussels, being generally more abundant in regions were predators were scarce or absent, and being less common in Ascophyllum than F. vesiculosus shores in contrast to the predatory dogwelks, were in large measure in accord with predictions from experiments indicating "top-down" regulation. The results for the periwinkles

  11. A Successful Crayfish Invader Is Capable of Facultative Parthenogenesis: A Novel Reproductive Mode in Decapod Crustaceans

    PubMed Central

    Buřič, Miloš; Hulák, Martin; Kouba, Antonín

    2011-01-01

    Biological invasions are impacting biota worldwide, and explaining why some taxa tend to become invasive is of major scientific interest. North American crayfish species, particularly of the family Cambaridae, are prominent invaders in freshwaters, defying the “tens rule” which states that only a minority of species introduced to new regions become established, and only a minority of those become invasive and pests. So far, success of cambarid invaders has largely been attributed to rapid maturation, high reproductive output, aggressiveness, and tolerance to pollution. We provide experimental evidence that females of one cambarid species particularly widespread in Europe, the spiny-cheek crayfish Orconectes limosus, are capable of facultative parthenogenesis. Such reproductive mode has never before been recognized in decapods, the most diverse crustacean order. As shown by analysis of seven microsatellite loci, crayfish females kept physically separated from males produced genetically homogeneous offspring identical with maternal individuals; this suggests they reproduced by apomixis, unlike those females which mated with males and had a diverse offspring. Further research is needed to clarify what environmental conditions are necessary for a switch to parthenogenesis in O. limosus, and what role it plays in natural crayfish populations. However, if such reproductive plasticity is present in other cambarid crayfish species, it may contribute to the overwhelming invasive success of this group. PMID:21655282

  12. Laboratory generation of new parthenogenetic lineages supports contagious parthenogenesis in Artemia

    PubMed Central

    Amat, Francisco; Hontoria, Francisco; Gómez, Africa

    2014-01-01

    Contagious parthenogenesis—a process involving rare functional males produced by a parthenogenetic lineage which mate with coexisting sexual females resulting in fertile parthenogenetic offspring—is one of the most striking mechanisms responsible for the generation of new parthenogenetic lineages. Populations of the parthenogenetic diploid brine shrimp Artemia produce fully functional males in low proportions. The evolutionary role of these so-called Artemia rare males is, however, unknown. Here we investigate whether new parthenogenetic clones could be obtained in the laboratory by mating these rare males with sexual females. We assessed the survival and sex ratio of the hybrid ovoviviparous offspring from previous crosses between rare males and females from all Asiatic sexual species, carried out cross-mating experiments between F1 hybrid individuals to assess their fertility, and estimated the viability and the reproductive mode of the resulting F2 offspring. Molecular analysis confirmed the parentage of hybrid parthenogenetic F2. Our study documents the first laboratory synthesis of new parthenogenetic lineages in Artemia and supports a model for the contagious spread of parthenogenesis. Our results suggest recessive inheritance but further experiments are required to confirm the likelihood of the contagious parthenogenesis model. PMID:25024909

  13. Geographical Distribution of Federal Science Funds to Colleges and Universities. Report of the Comptroller General of the United States.

    ERIC Educational Resources Information Center

    Comptroller General of the U.S., Washington, DC.

    This report provides data on the geographical distribution patterns of federal research and development and other funds to colleges and universities, information on federal programs established in the 1960's to strengthen academic science, and factors accounting for progress by universities in competing for federal funds. Summarizing statements…

  14. Induced parthenogenesis by gamma-irradiated pollen in loquat for haploid production

    PubMed Central

    Blasco, Manuel; Badenes, María Luisa; del Mar Naval, María

    2016-01-01

    Successful haploid induction in loquat (Eriobotrya japonica (Thunb.) Lindl.) through in situ-induced parthenogenesis with gamma-ray irradiated pollen has been achieved. Female flowers of cultivar ‘Algerie’ were pollinated using pollen of cultivars ‘Changhong-3’, ‘Cox’ and ‘Saval Brasil’ irradiated with two doses of gamma rays, 150 and 300 Gy. The fruits were harvested 90, 105 and 120 days after pollination (dap). Four haploid plants were obtained from ‘Algerie’ pollinated with 300-Gy-treated pollen of ‘Saval Brasil’ from fruits harvested 105 dap. Haploidy was confirmed by flow cytometry and chromosome count. The haploids showed a very weak development compared to the diploid plants. This result suggests that irradiated pollen can be used to obtain parthenogenetic haploids. PMID:27795686

  15. Tissue engineering, stem cells, cloning, and parthenogenesis: new paradigms for therapy

    PubMed Central

    Hipp, Jason; Atala, Anthony

    2004-01-01

    Patients suffering from diseased and injured organs may be treated with transplanted organs. However, there is a severe shortage of donor organs which is worsening yearly due to the aging population. Scientists in the field of tissue engineering apply the principles of cell transplantation, materials science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. Both therapeutic cloning (nucleus from a donor cell is transferred into an enucleated oocyte), and parthenogenesis (oocyte is activated and stimulated to divide), permit extraction of pluripotent embryonic stem cells, and offer a potentially limitless source of cells for tissue engineering applications. The stem cell field is also advancing rapidly, opening new options for therapy. The present article reviews recent progress in tissue engineering and describes applications of these new technologies that may offer novel therapies for patients with end-stage organ failure. PMID:15588286

  16. Apomictic parthenogenesis in a parasitoid wasp Meteorus pulchricornis, uncommon in the haplodiploid order Hymenoptera.

    PubMed

    Tsutsui, Y; Maeto, K; Hamaguchi, K; Isaki, Y; Takami, Y; Naito, T; Miura, K

    2014-06-01

    Although apomixis is the most common form of parthenogenesis in diplodiploid arthropods, it is uncommon in the haplodiploid insect order Hymenoptera. We found a new type of spontaneous apomixis in the Hymenoptera, completely lacking meiosis and the expulsion of polar bodies in egg maturation division, on the thelytokous strain of a parasitoid wasp Meteorus pulchricornis (Wesmael) (Braconidae, Euphorinae) on pest lepidopteran larvae Spodoptera litura (Fabricius) (Noctuidae). The absence of the meiotic process was consistent with a non-segregation pattern in the offspring of heterozygous females, and no positive evidence was obtained for the induction of thelytoky by any bacterial symbionts. We discuss the conditions that enable the occurrence of such rare cases of apomictic thelytoky in the Hymenoptera, suggesting the significance of fixed heterosis caused by hybridization or polyploidization, symbiosis with bacterial agents, and occasional sex. Our finding will encourage further genetic studies on parasitoid wasps to use asexual lines more wisely for biological control. PMID:24521569

  17. First record of second-generation facultative parthenogenesis in a vertebrate species, the whitespotted bambooshark Chiloscyllium plagiosum.

    PubMed

    Straube, N; Lampert, K P; Geiger, M F; Weiß, J D; Kirchhauser, J X

    2016-02-01

    In this study, two parthenogenetic events within a family of the whitespotted bambooshark Chiloscyllium plagiosum are reported. A captive female produced multiple parthenogens. Unexpectedly, a single specimen of a total of nine parthenogens displayed external claspers characterizing the male sex in chondrichthyans. Upon dissection, internal sexual organs of this specimen were malformed or absent; however, the presence of claspers in this study challenges the as yet assumed sex determination system in this shark species. Even more remarkable was that one of the female parthenogens reproduced asexually again producing viable offspring. As far as is known, this is the first genetically confirmed evidence for second-generation facultative parthenogenesis in vertebrates. These results support the evolutionary significance of parthenogenesis as an alternative to sexual reproduction. PMID:26727105

  18. First record of second-generation facultative parthenogenesis in a vertebrate species, the whitespotted bambooshark Chiloscyllium plagiosum.

    PubMed

    Straube, N; Lampert, K P; Geiger, M F; Weiß, J D; Kirchhauser, J X

    2016-02-01

    In this study, two parthenogenetic events within a family of the whitespotted bambooshark Chiloscyllium plagiosum are reported. A captive female produced multiple parthenogens. Unexpectedly, a single specimen of a total of nine parthenogens displayed external claspers characterizing the male sex in chondrichthyans. Upon dissection, internal sexual organs of this specimen were malformed or absent; however, the presence of claspers in this study challenges the as yet assumed sex determination system in this shark species. Even more remarkable was that one of the female parthenogens reproduced asexually again producing viable offspring. As far as is known, this is the first genetically confirmed evidence for second-generation facultative parthenogenesis in vertebrates. These results support the evolutionary significance of parthenogenesis as an alternative to sexual reproduction.

  19. Parthenogenesis-derived Multipotent Stem Cells Adapted for Tissue Engineering Applications

    PubMed Central

    Koh, Chester J.; Delo, Dawn M.; Lee, Jang Won; Siddiqui, M. Minhaj; Lanza, Robert P.; Soker, Shay; Yoo, James J.; Atala, Anthony

    2009-01-01

    Embryonic stem cells are envisioned as a viable source of pluripotent cells for use in regenerative medicine applications when donor tissue is not available. However, most current harvest techniques for embryonic stem cells require the destruction of embryos, which has led to significant political and ethical limitations on their usage. Parthenogenesis, the process by which an egg can develop into an embryo in the absence of sperm, may be a potential source of embryonic stem cells that may avoid some of the political and ethical concerns surrounding embryonic stem cells. Here we provide the technical aspects of embryonic stem cell isolation and expansion from the parthenogenetic activation of oocytes. These cells were characterized for their stem-cell properties. In addition, these cells were induced to differentiate to the myogenic, osteogenic, adipogenic, and endothelial lineages, and were able to form muscle-like and bony-like tissue in vivo. Furthermore, parthenogenetic stem cells were able to integrate into injured muscle tissue. Together, these results demonstrate that parthenogenetic stem cells can be successfully isolated and utilized for various tissue engineering applications. PMID:18799133

  20. Artificial parthenogenesis and control of voltinism to manage transgenic populations in Bombyx mori.

    PubMed

    Grenier, Anne-Marie; Da Rocha, Martine; Jalabert, Audrey; Royer, Corinne; Mauchamp, Bernard; Chavancy, Gérard

    2004-08-01

    In order to improve the management of transformed populations in a routine application of transgenesis technology in Bombyx mori, we modified its mode of reproduction and its voltinism. On one hand, after a stable integration of the gene of interest by transgenesis, it is preferable to maintain this gene in an identical genomic context through successive generations. This can be obtained by artificial parthenogenetic reproduction (ameiotic parthenogenesis) giving isogenic females identical to their transformed mother. On the other hand, it is essential to obtain continuous generations (polyvoltinism) after microinjection, in order to screen positive transgenic insects and study genetics and insertion of the transgene. Thereafter, it is more convenient to store these populations, as diapause eggs before their use in biotechnology application. We obtained such polyvoltine parthenoclones, first by selection for a parthenogenetic character in polyvoltine races, and second, by selection for a polyvoltine character in a parthenogenetic, but diapausing clone of B. mori. As diapause was directly under the control of diapause hormone (DH), we also tested direct injection of DH in female pupae of polyvoltine strains, as well as anti-DH antibody treatment to eliminate diapause in univoltine strains. We discussed the advantages and limitations of these methods and proved the feasibility in obtaining polyvoltine parthenoclones and determining the voltinism in B. mori. These methods would permit us to improve the management of populations used in transgenesis technology.

  1. Geographical DNA

    NASA Astrophysics Data System (ADS)

    Wojtanowicz, Paweł

    2012-01-01

    The article shows the results of a study undertaken to search for a model illustrating the development of geographical thought. The created model, formulated with a triad that defines geography: human being-space-time, displays levels merging geographical sciences. These joining elements created by geographers, more or less consciously cooperating with the representatives of other sciences, seem to be the essence of the unity of the continuously spreading study range of geography.

  2. A Parthenogenesis Gene Candidate and Evidence for Segmental Allopolyploidy in Apomictic Brachiaria decumbens.

    PubMed

    Worthington, Margaret; Heffelfinger, Christopher; Bernal, Diana; Quintero, Constanza; Zapata, Yeny Patricia; Perez, Juan Guillermo; De Vega, Jose; Miles, John; Dellaporta, Stephen; Tohme, Joe

    2016-07-01

    Apomixis, asexual reproduction through seed, enables breeders to identify and faithfully propagate superior heterozygous genotypes by seed without the disadvantages of vegetative propagation or the expense and complexity of hybrid seed production. The availability of new tools such as genotyping by sequencing and bioinformatics pipelines for species lacking reference genomes now makes the construction of dense maps possible in apomictic species, despite complications including polyploidy, multisomic inheritance, self-incompatibility, and high levels of heterozygosity. In this study, we developed saturated linkage maps for the maternal and paternal genomes of an interspecific Brachiaria ruziziensis (R. Germ. and C. M. Evrard) × B. decumbens Stapf. F1 mapping population in order to identify markers linked to apomixis. High-resolution molecular karyotyping and comparative genomics with Setaria italica (L.) P. Beauv provided conclusive evidence for segmental allopolyploidy in B. decumbens, with strong preferential pairing of homologs across the genome and multisomic segregation relatively more common in chromosome 8. The apospory-specific genomic region (ASGR) was mapped to a region of reduced recombination on B. decumbens chromosome 5. The Pennisetum squamulatum (L.) R.Br. PsASGR-BABY BOOM-like (psASGR-BBML)-specific primer pair p779/p780 was in perfect linkage with the ASGR in the F1 mapping population and diagnostic for reproductive mode in a diversity panel of known sexual and apomict Brachiaria (Trin.) Griseb. and P. maximum Jacq. germplasm accessions and cultivars. These findings indicate that ASGR-BBML gene sequences are highly conserved across the Paniceae and add further support for the postulation of the ASGR-BBML as candidate genes for the apomictic function of parthenogenesis.

  3. A Parthenogenesis Gene Candidate and Evidence for Segmental Allopolyploidy in Apomictic Brachiaria decumbens

    PubMed Central

    Worthington, Margaret; Heffelfinger, Christopher; Bernal, Diana; Quintero, Constanza; Zapata, Yeny Patricia; Perez, Juan Guillermo; De Vega, Jose; Miles, John; Dellaporta, Stephen; Tohme, Joe

    2016-01-01

    Apomixis, asexual reproduction through seed, enables breeders to identify and faithfully propagate superior heterozygous genotypes by seed without the disadvantages of vegetative propagation or the expense and complexity of hybrid seed production. The availability of new tools such as genotyping by sequencing and bioinformatics pipelines for species lacking reference genomes now makes the construction of dense maps possible in apomictic species, despite complications including polyploidy, multisomic inheritance, self-incompatibility, and high levels of heterozygosity. In this study, we developed saturated linkage maps for the maternal and paternal genomes of an interspecific Brachiaria ruziziensis (R. Germ. and C. M. Evrard) × B. decumbens Stapf. F1 mapping population in order to identify markers linked to apomixis. High-resolution molecular karyotyping and comparative genomics with Setaria italica (L.) P. Beauv provided conclusive evidence for segmental allopolyploidy in B. decumbens, with strong preferential pairing of homologs across the genome and multisomic segregation relatively more common in chromosome 8. The apospory-specific genomic region (ASGR) was mapped to a region of reduced recombination on B. decumbens chromosome 5. The Pennisetum squamulatum (L.) R.Br. PsASGR-BABY BOOM-like (psASGR–BBML)-specific primer pair p779/p780 was in perfect linkage with the ASGR in the F1 mapping population and diagnostic for reproductive mode in a diversity panel of known sexual and apomict Brachiaria (Trin.) Griseb. and P. maximum Jacq. germplasm accessions and cultivars. These findings indicate that ASGR–BBML gene sequences are highly conserved across the Paniceae and add further support for the postulation of the ASGR–BBML as candidate genes for the apomictic function of parthenogenesis. PMID:27206716

  4. A Parthenogenesis Gene Candidate and Evidence for Segmental Allopolyploidy in Apomictic Brachiaria decumbens.

    PubMed

    Worthington, Margaret; Heffelfinger, Christopher; Bernal, Diana; Quintero, Constanza; Zapata, Yeny Patricia; Perez, Juan Guillermo; De Vega, Jose; Miles, John; Dellaporta, Stephen; Tohme, Joe

    2016-07-01

    Apomixis, asexual reproduction through seed, enables breeders to identify and faithfully propagate superior heterozygous genotypes by seed without the disadvantages of vegetative propagation or the expense and complexity of hybrid seed production. The availability of new tools such as genotyping by sequencing and bioinformatics pipelines for species lacking reference genomes now makes the construction of dense maps possible in apomictic species, despite complications including polyploidy, multisomic inheritance, self-incompatibility, and high levels of heterozygosity. In this study, we developed saturated linkage maps for the maternal and paternal genomes of an interspecific Brachiaria ruziziensis (R. Germ. and C. M. Evrard) × B. decumbens Stapf. F1 mapping population in order to identify markers linked to apomixis. High-resolution molecular karyotyping and comparative genomics with Setaria italica (L.) P. Beauv provided conclusive evidence for segmental allopolyploidy in B. decumbens, with strong preferential pairing of homologs across the genome and multisomic segregation relatively more common in chromosome 8. The apospory-specific genomic region (ASGR) was mapped to a region of reduced recombination on B. decumbens chromosome 5. The Pennisetum squamulatum (L.) R.Br. PsASGR-BABY BOOM-like (psASGR-BBML)-specific primer pair p779/p780 was in perfect linkage with the ASGR in the F1 mapping population and diagnostic for reproductive mode in a diversity panel of known sexual and apomict Brachiaria (Trin.) Griseb. and P. maximum Jacq. germplasm accessions and cultivars. These findings indicate that ASGR-BBML gene sequences are highly conserved across the Paniceae and add further support for the postulation of the ASGR-BBML as candidate genes for the apomictic function of parthenogenesis. PMID:27206716

  5. Geographic tongue

    MedlinePlus

    Patches on the tongue; Tongue - patchy; Benign migratory glossitis; Glossitis - benign migratory ... The exact cause of geographic tongue is unknown. It may be caused by a lack of vitamin B. It also may be due to irritation from hot ...

  6. A methylation status analysis of the apomixis-specific region in Paspalum spp. suggests an epigenetic control of parthenogenesis.

    PubMed

    Podio, Maricel; Cáceres, Maria E; Samoluk, Sergio S; Seijo, José G; Pessino, Silvina C; Ortiz, Juan Pablo A; Pupilli, Fulvio

    2014-12-01

    Apomixis, a clonal plant reproduction by seeds, is controlled in Paspalum spp. by a single locus which is blocked in terms of recombination. Partial sequence analysis of the apomixis locus revealed structural features of heterochromatin, namely the presence of repetitive elements, gene degeneration, and de-regulation. To test the epigenetic control of apomixis, a study on the distribution of cytosine methylation at the apomixis locus and the effect of artificial DNA demethylation on the mode of reproduction was undertaken in two apomictic Paspalum species. The 5-methylcytosine distribution in the apomixis-controlling genomic region was studied in P. simplex by methylation-sensitive restriction fragment length polymorphism (RFLP) analysis and in P. notatum by fluorescene in situ hybridization (FISH). The effect of DNA demethylation was studied on the mode of reproduction of P. simplex by progeny test analysis of apomictic plants treated with the demethylating agent 5'-azacytidine. A high level of cytosine methylation was detected at the apomixis-controlling genomic region in both species. By analysing a total of 374 open pollination progeny, it was found that artificial demethylation had little or no effect on apospory, whereas it induced a significant depression of parthenogenesis. The results suggested that factors controlling repression of parthenogenesis might be inactivated in apomictic Paspalum by DNA methylation.

  7. A methylation status analysis of the apomixis-specific region in Paspalum spp. suggests an epigenetic control of parthenogenesis.

    PubMed

    Podio, Maricel; Cáceres, Maria E; Samoluk, Sergio S; Seijo, José G; Pessino, Silvina C; Ortiz, Juan Pablo A; Pupilli, Fulvio

    2014-12-01

    Apomixis, a clonal plant reproduction by seeds, is controlled in Paspalum spp. by a single locus which is blocked in terms of recombination. Partial sequence analysis of the apomixis locus revealed structural features of heterochromatin, namely the presence of repetitive elements, gene degeneration, and de-regulation. To test the epigenetic control of apomixis, a study on the distribution of cytosine methylation at the apomixis locus and the effect of artificial DNA demethylation on the mode of reproduction was undertaken in two apomictic Paspalum species. The 5-methylcytosine distribution in the apomixis-controlling genomic region was studied in P. simplex by methylation-sensitive restriction fragment length polymorphism (RFLP) analysis and in P. notatum by fluorescene in situ hybridization (FISH). The effect of DNA demethylation was studied on the mode of reproduction of P. simplex by progeny test analysis of apomictic plants treated with the demethylating agent 5'-azacytidine. A high level of cytosine methylation was detected at the apomixis-controlling genomic region in both species. By analysing a total of 374 open pollination progeny, it was found that artificial demethylation had little or no effect on apospory, whereas it induced a significant depression of parthenogenesis. The results suggested that factors controlling repression of parthenogenesis might be inactivated in apomictic Paspalum by DNA methylation. PMID:25180110

  8. Geographical Theories.

    ERIC Educational Resources Information Center

    Golledge, Reginald G.

    1996-01-01

    Discusses the origin of theories in geography and particularly the development of location theories. Considers the influence of economic theory on agricultural land use, industrial location, and geographic location theories. Explores a set of interrelated activities that show how the marketing process illustrates process theory. (MJP)

  9. Gene Expression Analysis of Parthenogenetic Embryonic Development of the Pea Aphid, Acyrthosiphon pisum, Suggests That Aphid Parthenogenesis Evolved from Meiotic Oogenesis

    PubMed Central

    Srinivasan, Dayalan G.; Abdelhady, Ahmed; Stern, David L.

    2014-01-01

    Aphids exhibit a form of phenotypic plasticity, called polyphenism, in which genetically identical females reproduce sexually during one part of the life cycle and asexually (via parthenogenesis) during the remainder of the life cycle. The molecular basis for aphid parthenogenesis is unknown. Cytological observations of aphid parthenogenesis suggest that asexual oogenesis evolved either through a modification of meiosis or from a mitotic process. As a test of these alternatives, we assessed the expression levels and expression patterns of canonical meiotic recombination and germline genes in the sexual and asexual ovaries of the pea aphid, Acyrthosiphon pisum. We observed expression of all meiosis genes in similar patterns in asexual and sexual ovaries, with the exception that some genes encoding Argonaute-family members were not expressed in sexual ovaries. In addition, we observed that asexual aphid tissues accumulated unspliced transcripts of Spo11, whereas sexual aphid tissues accumulated primarily spliced transcripts. In situ hybridization revealed Spo11 transcript in sexual germ cells and undetectable levels of Spo11 transcript in asexual germ cells. We also found that an obligately asexual strain of pea aphid produced little spliced Spo11 transcript. Together, these results suggest that parthenogenetic oogenesis evolved from a meiosis-like, and not a mitosis-like, process and that the aphid reproductive polyphenism may involve a modification of Spo11 gene activity. PMID:25501006

  10. Geographic Information Systems.

    PubMed

    Wieczorek, William F; Delmerico, Alan M

    2009-01-01

    spatial data and related phenomena. The capabilities of GIS are much more than just mapping, although map production is one of the most utilized features. GIS applications are relevant in a tremendous number of areas ranging from basic geographic inventories to simulation models.This chapter presents a general overview of geographic information system topics. The purpose is to provide the reader with a basic understanding of a GIS, the types of data that are needed, the basic functionality of these systems, the role of spatial analysis, and an example in the form of a case study. The chapter is designed to provide advanced students and experts outside of the field of GIS sufficient information to begin to utilize GIS and spatial analytic concepts, but it is not designed to be the sole basis for becoming a GIS expert. There is a tremendous level of sophistication related to the digital cartographic databases and manipulation of those databases underlying the display and use of GIS that is more appropriately a part of geographic information science (i.e., basic research issues associated with geographic data including technical as well as theoretical aspects such as the impact on society [1]) rather than being relevant to this chapter. The utilization of GIS for conducting spatial analysis is the guiding theme for the chapter.

  11. 33 CFR 167.3 - Geographic coordinates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Geographic coordinates. 167.3...) PORTS AND WATERWAYS SAFETY OFFSHORE TRAFFIC SEPARATION SCHEMES General § 167.3 Geographic coordinates. Geographic coordinates are defined using North American 1927 Datum (NAD 27) unless indicated otherwise....

  12. 33 CFR 166.103 - Geographic coordinates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Geographic coordinates. 166.103...) PORTS AND WATERWAYS SAFETY SHIPPING SAFETY FAIRWAYS General § 166.103 Geographic coordinates. Geographic coordinates expressed in terms of latitude or longitude, or both, are not intended for plotting on maps...

  13. A newly discovered bacterium associated with parthenogenesis and a change in host selection behavior in parasitoid wasps

    PubMed Central

    Zchori-Fein, E.; Gottlieb, Y.; Kelly, S. E.; Brown, J. K.; Wilson, J. M.; Karr, T. L.; Hunter, M. S.

    2001-01-01

    The symbiotic bacterium Wolbachia pipientis has been considered unique in its ability to cause multiple reproductive anomalies in its arthropod hosts. Here we report that an undescribed bacterium is vertically transmitted and associated with thelytokous parthenogenetic reproduction in Encarsia, a genus of parasitoid wasps. Although Wolbachia was found in only one of seven parthenogenetic Encarsia populations examined, the “Encarsia bacterium” (EB) was found in the other six. Among seven sexually reproducing populations screened, EB was present in one, and none harbored Wolbachia. Antibiotic treatment did not induce male production in Encarsia pergandiella but changed the oviposition behavior of females. Cured females accepted one host type at the same rate as control females but parasitized significantly fewer of the other host type. Phylogenetic analysis based on the 16S rDNA gene sequence places the EB in a unique clade within the Cytophaga-Flexibacter-Bacteroid group and shows EB is unrelated to the Proteobacteria, where Wolbachia and most other insect symbionts are found. These results imply evolution of the induction of parthenogenesis in a lineage other than Wolbachia. Importantly, these results also suggest that EB may modify the behavior of its wasp carrier in a way that enhances its transmission. PMID:11592990

  14. Survival and Reproductive Strategies in Two-Spotted Spider Mites: Demographic Analysis of Arrhenotokous Parthenogenesis of Tetranychus urticae (Acari: Tetranychidae).

    PubMed

    Tuan, Shu-Jen; Lin, Yung-Hsiang; Yang, Chung-Ming; Atlihan, Remzi; Saska, Pavel; Chi, Hsin

    2016-04-01

    Tetranychus urticae Koch is a cosmopolitan pest whose rapid developmental rate enables it to produce colonies of thousands of individuals within a short time period. When a solitary virgin female colonizes a new host plant, it is capable of producing male offspring through the arrhenotokous parthenogenesis; once her sons mature, oedipal mating occurs and the female will produce bisexual offspring. To analyze the effect of arrhenotokous reproduction on population growth, we devised and compared separate life tables for arrhenotokous and bisexual populations of T. urticae using the age-stage, two-sex life table theory. For the cohort with bisexual reproduction, the intrinsic rate of increase (r), finite rate (λ), net reproductive rate (R0), and mean generation time (T) were 0.2736 d(−1), 1.3146 d(−1), 44.66 offspring, and 13.89 d, respectively. Because only male eggs were produced during the first 8 d of the oviposition period and the cohort would soon begin bisexual reproduction, it would be theoretically wrong to calculate the population parameters using the survival rate and fecundity of an arrhenotokous cohort. We demonstrated that the effect of arrhenotokous reproduction could be accurately described and evaluated using the age-stage, two-sex life table. We also used population projection based on life table data, quantitatively showing the effect that arrhenotokous reproduction has on the growth potential and management of T. urticae. PMID:26743215

  15. Survival and Reproductive Strategies in Two-Spotted Spider Mites: Demographic Analysis of Arrhenotokous Parthenogenesis of Tetranychus urticae (Acari: Tetranychidae).

    PubMed

    Tuan, Shu-Jen; Lin, Yung-Hsiang; Yang, Chung-Ming; Atlihan, Remzi; Saska, Pavel; Chi, Hsin

    2016-04-01

    Tetranychus urticae Koch is a cosmopolitan pest whose rapid developmental rate enables it to produce colonies of thousands of individuals within a short time period. When a solitary virgin female colonizes a new host plant, it is capable of producing male offspring through the arrhenotokous parthenogenesis; once her sons mature, oedipal mating occurs and the female will produce bisexual offspring. To analyze the effect of arrhenotokous reproduction on population growth, we devised and compared separate life tables for arrhenotokous and bisexual populations of T. urticae using the age-stage, two-sex life table theory. For the cohort with bisexual reproduction, the intrinsic rate of increase (r), finite rate (λ), net reproductive rate (R0), and mean generation time (T) were 0.2736 d(−1), 1.3146 d(−1), 44.66 offspring, and 13.89 d, respectively. Because only male eggs were produced during the first 8 d of the oviposition period and the cohort would soon begin bisexual reproduction, it would be theoretically wrong to calculate the population parameters using the survival rate and fecundity of an arrhenotokous cohort. We demonstrated that the effect of arrhenotokous reproduction could be accurately described and evaluated using the age-stage, two-sex life table. We also used population projection based on life table data, quantitatively showing the effect that arrhenotokous reproduction has on the growth potential and management of T. urticae.

  16. Occurrence of novel verrucomicrobial species, endosymbiotic and associated with parthenogenesis in Xiphinema americanum-group species (Nematoda, Longidoridae).

    PubMed

    Vandekerckhove, T T; Willems, A; Gillis, M; Coomans, A

    2000-11-01

    Numerous micro-organisms have been described as cytoplasmic symbionts of eukaryotes. Many so-called obligate endosymbionts rely exclusively on maternal (vertical or transovarial) transmission to maintain themselves, rendering them dependent on the host sex ratio, which they would tend to manipulate to their own advantage. The latter phenomenon is often associated with the presence of Wolbachia pipientis (alpha-Proteobacteria) in arthropods and nematodes. A potentially similar situation was discovered involving members of a new clade of Verrucomicrobia, another main line of descent in the Bacteria. Nematode species of the Xiphinema americanum group (Nematoda, Longidoridae), viz. Xiphinema americanum, Xiphinema rivesi and Xiphinema brevicollum, each harbour their own specific verrucomicrobial endosymbionts. They are exclusively maternally inherited and their hosts reproduce by thelytokous (mother-to-daughter) parthenogenesis, males being extremely rare. A new genus, 'Candidatus Xiphinematobacter' gen. nov., along with three new candidate verrucomicrobial species, 'Candidatus Xiphinematobacter americani' sp. nov., 'Candidatus Xiphinematobacter rivesi' sp. nov. and 'Candidatus Xiphinematobacter brevicolli' sp. nov., are described on the basis of transmission electron microscopy, scanning electron microscopy, DAPI (4',6-diamidino-2-phenylindole) epifluorescence microscopy and 16S rDNA sequence analysis. These are the first endosymbiotic species described among the Verrucomicrobia. They share a mean 16S rDNA similarity of about 93%, whereas similarity to their closest relative, clone WCHD3-88, is less than 87%. Thus, the endosymbionts form a homogeneous clade for which the new candidate genus 'Candidatus Xiphinematobacter' gen. nov. is proposed. The type species is 'Candidatus Xiphinematobacter brevicolli' sp. nov.

  17. Thinking Like a Geographer

    ERIC Educational Resources Information Center

    Chernosky, Margaret Shaw

    2012-01-01

    This article presents an activity that engages the student in the geographic inquiry process, the student acquires geographic data and analyzes geographic information to answer a geographic question. The question is: "Do students in my class have place name mastery of the 50 states?" The activity assesses students' geo-literacy and shows the…

  18. Thelytokous Parthenogenesis in the Fungus-Gardening Ant Mycocepurus smithii (Hymenoptera: Formicidae)

    PubMed Central

    Rabeling, Christian; Lino-Neto, José; Cappellari, Simone C.; Dos-Santos, Iracenir A.; Mueller, Ulrich G.; Bacci, Maurício

    2009-01-01

    The general prevalence of sexual reproduction over asexual reproduction among organisms testifies to the evolutionary benefits of recombination, such as accelerated adaptation to changing environments and elimination of deleterious mutations. Documented instances of asexual reproduction in groups otherwise dominated by sexual reproduction challenge evolutionary biologists to understand the special circumstances that might confer an advantage to asexual reproductive strategies. Here we report one such instance of asexual reproduction in the ants. We present evidence for obligate thelytoky in the asexual fungus-gardening ant, Mycocepurus smithii, in which queens produce female offspring from unfertilized eggs, workers are sterile, and males appear to be completely absent. Obligate thelytoky is implicated by reproductive physiology of queens, lack of males, absence of mating behavior, and natural history observations. An obligate thelytoky hypothesis is further supported by the absence of evidence indicating sexual reproduction or genetic recombination across the species' extensive distribution range (Mexico-Argentina). Potential conflicting evidence for sexual reproduction in this species derives from three Mycocepurus males reported in the literature, previously regarded as possible males of M. smithii. However, we show here that these specimens represent males of the congeneric species M. obsoletus, and not males of M. smithii. Mycocepurus smithii is unique among ants and among eusocial Hymenoptera, in that males seem to be completely absent and only queens (and not workers) produce diploid offspring via thelytoky. Because colonies consisting only of females can be propagated consecutively in the laboratory, M. smithii could be an adequate study organism a) to test hypotheses of the population-genetic advantages and disadvantages of asexual reproduction in a social organism and b) inform kin conflict theory. For a Portuguese translation of the abstract, please see

  19. Geographic Proximity and Enrollment Competition.

    ERIC Educational Resources Information Center

    Zammuto, Raymond F.

    The use of a measure of geographic proximity to help explain enrollment competition among postsecondary institutions was investigated. The measure, the number of miles between institutions, was obtained by determining the longitude and latitude coordinates for about 99% of the schools in the Higher Education General Information System universe.…

  20. Geographic Considerations in International Studies.

    ERIC Educational Resources Information Center

    Kott, Richard F.

    Based on students' generally shallow knowledge of geographic concepts on the one hand and a new and almost universal awareness of man in his milieu on the other, the author seeks to draw attention to the discipline of geography, and more specifically, political geography as an essential, fundamental component of international studies. The…

  1. Modes of inheritance of two apomixis components, diplospory and parthenogenesis, in Chinese chive (Allium ramosum) revealed by analysis of the segregating population generated by back-crossing between amphimictic and apomictic diploids.

    PubMed

    Yamashita, Ken-Ichiro; Nakazawa, Yoshiko; Namai, Kiyoshi; Amagai, Masayuki; Tsukazaki, Hikaru; Wako, Tadayuki; Kojima, Akio

    2012-06-01

    To investigate the mode of inheritance of apomixis in Chinese chive, the degrees of diplospory and parthenogenesis were evaluated in F(1) and BC(1) progenies derived from crosses between amphimictic and apomictic diploids (2n = 16, 2x). The F(1) population was generated by crossing three amphimictic diploids 94Mo13, 94Mo49 and 94Mo50 with an apomictic diploid KaD2 and comprised 110 diploids and 773 triploids. All the diploid F(1) plants examined were completely or highly eusporous and completely syngamic. All the triploid F(1) plants examined were highly diplosporous and highly parthenogenetic. KaD2 could not transmit its high level of apomixis via monoploid pollen grains. The BC(1) population, generated by crossing 94Mo49 with apomictic triploids found in the F(1) offspring, exhibited heteroploidy; it comprised haploid, diploid, triploid, tetraploid and various aneuploid individuals. In this generation, clear segregation was observed between diplospory and parthenogenesis. Analysis of the BC(1) population suggests that diplospory and parthenogenesis are each controlled by single dominant genes, D and P, respectively. However, all the BC(1) plants characterized as parthenogenetic were diplosporous. The absence of phenotypically eusporous parthenogenetic plants can be explained by assuming that the presence of diplospory gene is a prerequisite for the parthenogenesis gene expression in Chinese chive.

  2. Geographic Information Office

    USGS Publications Warehouse

    ,

    2004-01-01

    The Geographic Information Office (GIO) is the principal information office for U.S. Geological Survey (USGS), focused on: Information Policy and Services, Information Technology, Science Information, Information Security, and the Federal Geographic Data Committee/Geospatial One Stop.

  3. Geographic Media Literacy

    ERIC Educational Resources Information Center

    Lukinbeal, Chris

    2014-01-01

    While the use of media permeates geographic research and pedagogic practice, the underlying literacies that link geography and media remain uncharted. This article argues that geographic media literacy incorporates visual literacy, information technology literacy, information literacy, and media literacy. Geographic media literacy is the ability…

  4. 47 CFR 10.450 - Geographic targeting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Geographic targeting. 10.450 Section 10.450 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL WIRELESS EMERGENCY ALERTS Alert Message Requirements § 10.450 Geographic targeting. This section establishes minimum requirements for the...

  5. 47 CFR 10.450 - Geographic targeting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Geographic targeting. 10.450 Section 10.450 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL WIRELESS EMERGENCY ALERTS Alert Message Requirements § 10.450 Geographic targeting. This section establishes minimum requirements for the...

  6. [Geographic variations in freshwater molluscs].

    PubMed

    Vinarskiĭ, M V

    2012-01-01

    The phenomenon of geographic variation is known in practically all taxa of living beings. However, the reality of this phenomenon in freshwater molluscs (snails and bivalves) has many times been questioned in the past. It was accepted that these animals do not demonstrate spatially-oriented variation, where specific "local race" is arisen in each specific habitat. Till the beginning of 1970s, there was no statistical evidence that geographic clines in freshwater molluscs really exist. However, a few species of freshwater molluscs has been studied in this respect so far, therefore it is almost impossible to draw any general patterns of geographical variation in this group of animals. Most species of freshwater molluscs studied to the date exhibit statistically significant decrease of their body size in the south-north direction. Perhaps, it may be explained by decrease of the duration of the growth season in high latitudes. Some species of freshwater snails demonstrate clinal changes in shell proportions. This allows to reject subspecies separation within these species since diagnostic characters of such "subspecies" may blur when geographic variation is taken into consideration. The data on geographic variation in anatomical traits in freshwater molluscs is much more scarce. At least one species of pond snails (Lymnaea terebra) demonstrates clinal variation in proportions of the copulative apparatus in the south-north direction. Further studies of geographic variation in freshwater molluscs should reveal whether it is truly adaptive, i.e. whether geographical clines have underlying genetic basis. Otherwise, the clines may arise as a result of direct modifying effect of a habitat.

  7. Review and synthesis of problems and directions for large scale geographic information system development

    NASA Technical Reports Server (NTRS)

    Boyle, A. R.; Dangermond, J.; Marble, D.; Simonett, D. S.; Tomlinson, R. F.

    1983-01-01

    Problems and directions for large scale geographic information system development were reviewed and the general problems associated with automated geographic information systems and spatial data handling were addressed.

  8. Environmental geographic information system.

    SciTech Connect

    Peek, Dennis W; Helfrich, Donald Alan; Gorman, Susan

    2010-08-01

    This document describes how the Environmental Geographic Information System (EGIS) was used, along with externally received data, to create maps for the Site-Wide Environmental Impact Statement (SWEIS) Source Document project. Data quality among the various classes of geographic information system (GIS) data is addressed. A complete listing of map layers used is provided.

  9. Coloring geographical threshold graphs

    SciTech Connect

    Bradonjic, Milan; Percus, Allon; Muller, Tobias

    2008-01-01

    We propose a coloring algorithm for sparse random graphs generated by the geographical threshold graph (GTG) model, a generalization of random geometric graphs (RGG). In a GTG, nodes are distributed in a Euclidean space, and edges are assigned according to a threshold function involving the distance between nodes as well as randomly chosen node weights. The motivation for analyzing this model is that many real networks (e.g., wireless networks, the Internet, etc.) need to be studied by using a 'richer' stochastic model (which in this case includes both a distance between nodes and weights on the nodes). Here, we analyze the GTG coloring algorithm together with the graph's clique number, showing formally that in spite of the differences in structure between GTG and RGG, the asymptotic behavior of the chromatic number is identical: {chi}1n 1n n / 1n n (1 + {omicron}(1)). Finally, we consider the leading corrections to this expression, again using the coloring algorithm and clique number to provide bounds on the chromatic number. We show that the gap between the lower and upper bound is within C 1n n / (1n 1n n){sup 2}, and specify the constant C.

  10. Geographic names of Antarctica

    USGS Publications Warehouse

    ,; ,; Burrill, Meredith F.; Bertrand, Kenneth J.; Alberts, Fred G.

    1956-01-01

    The geographic nomenclature of Antarctica was long in need of an overall systematic treatment, objective in approach and based upon thorough examination of all the evidence. The results of such treatment over a period of about three years were presented in Geographical Names of Antarctica, Special Publication No. 86 of the Board on Geographical Names, in May 1947, two supplements to which were issued in 1949 and 1951. The continuing program since that publication has now covered most of the geographic naming in Antarctica. As research has filled in many of the previous gaps in knowledge, a number of names have been modified and minor amendments have been made in the policies. This revised publication brings together the greatly enlarged body of names officially standardized for use by the United States Government, together with new pertinent background information.

  11. Geographic Names Information System

    USGS Publications Warehouse

    U.S. Geological Survey

    1984-01-01

    The Geographic Names Information System (GNIS) is an automated data system developed by the U.S. Geological Survey (USGS) to standardize and disseminate information on geographic names. GNIS provides primary information for all known places, features, and areas in the United States identified by a proper name. The information in the system can be manipulated to meet varied needs. You can incorporate information from GNIS into your own data base for special applications.

  12. Relationship between the length of cell cycles, cleavage pattern and developmental competence in bovine embryos generated by in vitro fertilization or parthenogenesis.

    PubMed

    Somfai, Tamás; Inaba, Yasushi; Aikawa, Yoshio; Ohtake, Masaki; Kobayashi, Shuji; Konishi, Kazuyuki; Imai, Kei

    2010-04-01

    This study was conducted to study the kinetics of initial cell divisions in relation with the cleavage patterns in viable (with the ability to develop to the blastocyst stage) and non-viable bovine embryos and parthenotes. The kinetics of in vitro development and cleavage patterns were observed by time lapse cinematography. The length of the first and second but not third cell cycle differed significantly between the viable and non-viable embryos after IVF or parthenogenesis. Viable embryos had significantly shorter first and second cell cycles than non-viable ones. The presence of fragments, protrusions and unequally-sized blastomeres was associated with an extended one-cell stage and reduced ability to develop to the blastocyst stage; however, the lengths of the second and third cell cycles were not altered. Oocytes showing direct division from one cell to 3 or 4 blastomeres showed similar developmental ability and embryonic cell numbers to those showing normal division, although, with a high frequency of chromosomal abnormalities. Our results suggest that the differences in the first cell cycles between viable and non-viable embryos were not sperm-related, whereas direct cleavage of 1-cell embryos to 3 or more blastomeres and protrusion formation are related to sperm-driven factors. The length of the first and second cell cycles and the cleavage pattern should be examined simultaneously to predict developmental competence of embryos at early cleavage stages. PMID:20035110

  13. Have the implementation of a new specialised emergency medical service influenced the pattern of general practitioners involvement in pre-hospital medical emergencies? A study of geographic variations in alerting, dispatch, and response

    PubMed Central

    Vaardal, B; Lossius, H; Steen, P; Johnsen, R

    2005-01-01

    Methods: This was a prospective, observational cohort study of 385 000 inhabitants covered by the two EMDCs of Rogaland county, Norway, including 1035 on scene missions of the EP manned EMS during the period 1998–99. Results: The proportion of emergency calls routed through 113 was significantly lower, the proportion of alerts to GPs significantly higher, and the proportions of GPs on scene significantly higher in rural than urban areas. Conclusion: We found geographical differences in the involvement of GPs in pre-hospital emergency medical situations, probably caused by a specialised emergency medical service system including an EMDC and an air and ground EP manned EMS. There were geographical differences in public use of the toll free 113, and alerts to GPs by the EMDCs, which is likely to result from geographical conditions and proximity to medical resources. Future organisation of the EMS has to reflect this to prevent unplanned and unwanted autonomously emerging EMS systems. PMID:15735277

  14. Symposium on Geographic Information Systems.

    ERIC Educational Resources Information Center

    Felleman, John, Ed.

    1990-01-01

    Six papers on geographic information systems cover the future of geographic information systems, land information systems modernization in Wisconsin, the Topologically Integrated Geographic Encoding and Referencing (TIGER) System of the U.S. Bureau of the Census, satellite remote sensing, geographic information systems and sustainable development,…

  15. Research in Geographical Education.

    ERIC Educational Resources Information Center

    Wilson, Peter, Ed.; And Others

    This publication contains 19 papers presented at the inaugural meeting of the Australian Geographical Education Research Association held in Brisbane, December 1980. The papers surveyed a wide and diverse range of research. The introductory group of papers present several new views on curriculum development, course content, and teaching methods…

  16. Geographic information systems

    USGS Publications Warehouse

    ,

    1992-01-01

    Geographic information systems (GIS) technology can be used for scientific investigations, resource management, and developmental planning. For example, a GIS might allow emergency planners to easily calculate emergency response times in the event of a natural disaster, or a GIS might be used to find wetlands that need protection form pollution.

  17. Making Geographical Futures

    ERIC Educational Resources Information Center

    Morgan, John

    2015-01-01

    Although there are surprisingly few academic books about geography with the term "future" or "futures" in their titles, this paper indicates that for much of the twentieth century geographers contributed to important discussions about the shape of worlds to come. The paper offers a review of these debates within Anglo-American…

  18. Geographic Education in Louisiana

    ERIC Educational Resources Information Center

    Lewis, Anthony J.

    2004-01-01

    In this article, the author analyzes and summarizes geographic education in Louisiana from a historical perspective with a specific emphasis on the degree to which geography was implemented into the state's standards. To accomplish that, he draws from the following three sources of information: active and retired social studies teachers from a…

  19. Minimum variance geographic sampling

    NASA Technical Reports Server (NTRS)

    Terrell, G. R. (Principal Investigator)

    1980-01-01

    Resource inventories require samples with geographical scatter, sometimes not as widely spaced as would be hoped. A simple model of correlation over distances is used to create a minimum variance unbiased estimate population means. The fitting procedure is illustrated from data used to estimate Missouri corn acreage.

  20. Female parthenogenetic apomixis and androsporogenetic parthenogenesis in embryonal cells of Araucaria angustifolia: interpolation of progenesis and asexual heterospory in an artificial sporangium.

    PubMed

    Durzan, Don J

    2012-09-01

    Cell fate, development timing and occurrence of reproductive versus apomictic development in gymnosperms are shown to be influenced by culture conditions in vitro. In this study, female parthenogenetic apomixis (fPA), androsporogenetic parthenogenesis (mAP) and progenesis were demonstrated using embryonal initials of Araucaria angustifolia in scaled-up cell suspensions passing through a single-cell bottleneck in darkness and in an artificial sporangium (AS). Expression was based on defined nutrition, hormones and feedforward-adaptive feedback process controls at 23-25 °C and in darkness. In fPA, the nucleus of an embryonal initial undergoes endomitosis and amitosis, forming a diploid egg-equivalent and an apoptotic ventral canal nucleus in a transdifferentiated archegonial tube. Discharge of egg-equivalent cells as parthenospores and their dispersal into the aqueous culture medium were followed by free-nuclear conifer-type proembryogenesis. This replaced the plesiomorphic and central features of proembryogenesis in Araucariaceae. Protoplasmic fusions of embryonal initials were used to reconstruct heterokaryotic expressions of fPA in multiwell plates. In mAP, restitutional meiosis (automixis) was responsible for androsporogenesis and the discharge of monads, dyads, tetrads and polyads. In a display of progenesis, reproductive development was brought to an earlier ontogenetic stage and expressed by embryonal initials. Colchicine increased polyploidy, but androspore formation became aberrant and fragmented. Aberrant automixis led to the formation of chromosomal bouquets, which contributed to genomic silencing in embryonal initials, cytomixis and the formation of pycnotic micronucleated cells. Dispersal of female and male parthenospores displayed heteromorphic asexual heterospory in an aqueous environment. PMID:22669467

  1. Taxonomist’s Nightmare … Evolutionist’s Delight †: An Integrative Approach Resolves Species Limits in Jumping Bristletails Despite Widespread Hybridization and Parthenogenesis

    PubMed Central

    Dejaco, Thomas; Gassner, Melitta; Arthofer, Wolfgang; Schlick-Steiner, Birgit C.; Steiner, Florian M.

    2016-01-01

    . We hypothesize that an inherent affinity to hybridization, combined with parallel switches to parthenogenesis and repeated postglacial colonization events may have boosted endemicity in Eastern Alpine Machilis. We thus emphasize the importance of integrative taxonomy for rigorous species delimitation and its implication for evolutionary research and conservation in taxonomically challenging taxa. PMID:26869489

  2. Female parthenogenetic apomixis and androsporogenetic parthenogenesis in embryonal cells of Araucaria angustifolia: interpolation of progenesis and asexual heterospory in an artificial sporangium.

    PubMed

    Durzan, Don J

    2012-09-01

    Cell fate, development timing and occurrence of reproductive versus apomictic development in gymnosperms are shown to be influenced by culture conditions in vitro. In this study, female parthenogenetic apomixis (fPA), androsporogenetic parthenogenesis (mAP) and progenesis were demonstrated using embryonal initials of Araucaria angustifolia in scaled-up cell suspensions passing through a single-cell bottleneck in darkness and in an artificial sporangium (AS). Expression was based on defined nutrition, hormones and feedforward-adaptive feedback process controls at 23-25 °C and in darkness. In fPA, the nucleus of an embryonal initial undergoes endomitosis and amitosis, forming a diploid egg-equivalent and an apoptotic ventral canal nucleus in a transdifferentiated archegonial tube. Discharge of egg-equivalent cells as parthenospores and their dispersal into the aqueous culture medium were followed by free-nuclear conifer-type proembryogenesis. This replaced the plesiomorphic and central features of proembryogenesis in Araucariaceae. Protoplasmic fusions of embryonal initials were used to reconstruct heterokaryotic expressions of fPA in multiwell plates. In mAP, restitutional meiosis (automixis) was responsible for androsporogenesis and the discharge of monads, dyads, tetrads and polyads. In a display of progenesis, reproductive development was brought to an earlier ontogenetic stage and expressed by embryonal initials. Colchicine increased polyploidy, but androspore formation became aberrant and fragmented. Aberrant automixis led to the formation of chromosomal bouquets, which contributed to genomic silencing in embryonal initials, cytomixis and the formation of pycnotic micronucleated cells. Dispersal of female and male parthenospores displayed heteromorphic asexual heterospory in an aqueous environment.

  3. Geographic data from space

    USGS Publications Warehouse

    Alexander, Robert H.

    1964-01-01

    Space science has been called “the collection of scientific problems to which space vehicles can make some specific contributions not achievable by ground-based experiments.” Geography, the most spatial of the sciences, has now been marked as one of these “space sciences.” The National Aeronautics and Space Administration (NASA) is sponsoring an investigation to identify the Potential geographic benefits from the nation’s space program. This is part of NASA’s long-range inquiry to determine the kinds of scientific activities which might profitably be carried out on future space missions. Among such future activities which are now being planned by NASA are a series of manned earth orbital missions, many of which would be devoted to research. Experiments in physics, astronomy, geophysics, meteorology, and biology are being discussed for these long-range missions. The question which is being put to geographers is, essentially, what would it mean to geographic research to have an observation satellite (or many such satellites) orbiting the earth, gathering data about earth-surface features and environments?

  4. The National Map - Geographic Names

    USGS Publications Warehouse

    ,

    2002-01-01

    Governments depend on a common set of base geographic information as a tool for economic and community development, land and natural resource management, and health and safety services. Emergency management and homeland security applications rely on this information. Private industry, nongovernmental organizations, and individual citizens use the same geographic data. Geographic information underpins an increasingly large part of the Nation's economy.

  5. Volunteered Geographic Information in Wikipedia

    ERIC Educational Resources Information Center

    Hardy, Darren

    2010-01-01

    Volunteered geographic information (VGI) refers to the geographic subset of online user-generated content. Through Geobrowsers and online mapping services, which use geovisualization and Web technologies to share and produce VGI, a global digital commons of geographic information has emerged. A notable example is Wikipedia, an online collaborative…

  6. Geographic science team

    NASA Technical Reports Server (NTRS)

    Bryant, N.

    1982-01-01

    The rational for using remote sensing in land use/land cover, geomorphology, and cartography applications is stated as well as potential uses in each of these areas. The next step to be perfected is indicated. Spatial and spectral resolution requirements for photointerpretations and/or multispectral pattern recognition of geomorphic elements and of cultural surface cover are listed. Requirements for photographic/analog or digital photogrammetry from spaceborne multispectral linear array sensors are included. A prioritized summary of data gaps in the geographic sciences is included.

  7. Geographic information systems

    NASA Technical Reports Server (NTRS)

    Campbell, W. J.

    1982-01-01

    Information and activities are provided to: (1) enhance the ability to distinguish between a Geographic Information System (GIS) and a data management system; (2) develop understanding of spatial data handling by conventional methods versus the automated approach; (3) promote awareness of GIS design and capabilities; (4) foster understanding of the concepts and problems of data base development and management; (5) facilitate recognition of how a computerized GIS can model conditions in the present "real world" to project conditions in the future; and (6) appreciate the utility of integrating LANDSAT and other remotely sensed data into the GIS.

  8. Comparison of immunization strategies in geographical networks

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Aihara, Kazuyuki; Kim, Beom Jun

    2009-10-01

    The epidemic spread and immunizations in geographically embedded scale-free (SF) and Watts-Strogatz (WS) networks are numerically investigated. We make a realistic assumption that it takes time which we call the detection time, for a vertex to be identified as infected, and implement two different immunization strategies: one is based on connection neighbors (CN) of the infected vertex with the exact information of the network structure utilized and the other is based on spatial neighbors (SN) with only geographical distances taken into account. We find that the decrease of the detection time is crucial for a successful immunization in general. Simulation results show that for both SF networks and WS networks, the SN strategy always performs better than the CN strategy, especially for more heterogeneous SF networks at long detection time. The observation is verified by checking the number of the infected nodes being immunized. We found that in geographical space, the distance preferences in the network construction process and the geographically decaying infection rate are key factors that make the SN immunization strategy outperforms the CN strategy. It indicates that even in the absence of the full knowledge of network connectivity we can still stop the epidemic spread efficiently only by using geographical information as in the SN strategy, which may have potential applications for preventing the real epidemic spread.

  9. Patterns and causes of geographic variation in bat echolocation pulses.

    PubMed

    Jiang, Tinglei; Wu, Hui; Feng, Jiang

    2015-05-01

    Evolutionary biologists have a long-standing interest in how acoustic signals in animals vary geographically, because divergent ecology and sensory perception play an important role in speciation. Geographic comparisons are valuable in determining the factors that influence divergence of acoustic signals. Bats are social mammals and they depend mainly on echolocation pulses to locate prey, to navigate and to communicate. Mounting evidence shows that geographic variation of bat echolocation pulses is common, with a mean 5-10 kHz differences in peak frequency, and a high level of individual variation may be nested in this geographical variation. However, understanding the geographic variation of echolocation pulses in bats is very difficult, because of differences in sample and statistical analysis techniques as well as the variety of factors shaping the vocal geographic evolution. Geographic differences in echolocation pulses of bats generally lack latitudinal, longitudinal and elevational patterns, and little is known about vocal dialects. Evidence is accumulating to support the fact that geographic variation in echolocation pulses of bats may be caused by genetic drift, cultural drift, ecological selection, sexual selection and social selection. Future studies could relate geographic differences in echolocation pulses to social adaptation, vocal learning strategies and patterns of dispersal. In addition, new statistical techniques and acoustic playback experiments may help to illustrate the causes and consequences of the geographic evolution of echolocation pulse in bats. PMID:25664901

  10. Analyzing geographic clustered response

    SciTech Connect

    Merrill, D.W.; Selvin, S.; Mohr, M.S.

    1991-08-01

    In the study of geographic disease clusters, an alternative to traditional methods based on rates is to analyze case locations on a transformed map in which population density is everywhere equal. Although the analyst's task is thereby simplified, the specification of the density equalizing map projection (DEMP) itself is not simple and continues to be the subject of considerable research. Here a new DEMP algorithm is described, which avoids some of the difficulties of earlier approaches. The new algorithm (a) avoids illegal overlapping of transformed polygons; (b) finds the unique solution that minimizes map distortion; (c) provides constant magnification over each map polygon; (d) defines a continuous transformation over the entire map domain; (e) defines an inverse transformation; (f) can accept optional constraints such as fixed boundaries; and (g) can use commercially supported minimization software. Work is continuing to improve computing efficiency and improve the algorithm. 21 refs., 15 figs., 2 tabs.

  11. Geographic range limits: achieving synthesis

    PubMed Central

    Gaston, Kevin J.

    2009-01-01

    Understanding of the determinants of species' geographic range limits remains poorly integrated. In part, this is because of the diversity of perspectives on the issue, and because empirical studies have lagged substantially behind developments in theory. Here, I provide a broad overview, drawing together many of the disparate threads, considering, in turn, how influences on the terms of a simple single-population equation can determine range limits. There is theoretical and empirical evidence for systematic changes towards range limits under some circumstances in each of the demographic parameters. However, under other circumstances, no such changes may take place in particular parameters, or they may occur in a different direction, with limitation still occurring. This suggests that (i) little about range limitation can categorically be inferred from many empirical studies, which document change in only one demographic parameter, (ii) there is a need for studies that document variation in all of the parameters, and (iii) in agreement with theoretical evidence that range limits can be formed in the presence or absence of hard boundaries, environmental gradients or biotic interactions, there may be few general patterns as to the determinants of these limits, with most claimed generalities at least having many exceptions. PMID:19324809

  12. Parthenogenesis and Human Assisted Reproduction

    PubMed Central

    Bos-Mikich, Adriana; Bressan, Fabiana F.; Ruggeri, Rafael R.; Watanabe, Yeda; Meirelles, Flávio V.

    2016-01-01

    Parthenogenetic activation of human oocytes obtained from infertility treatments has gained new interest in recent years as an alternative approach to create embryos with no reproductive purpose for research in areas such as assisted reproduction technologies itself, somatic cell, and nuclear transfer experiments and for derivation of clinical grade pluripotent embryonic stem cells for regenerative medicine. Different activating methods have been tested on human and nonhuman oocytes, with varying degrees of success in terms of parthenote generation rates, embryo development stem cell derivation rates. Success in achieving a standardized artificial activation methodology for human oocytes and the subsequent potential therapeutic gain obtained from these embryos depends mainly on the availability of gametes donated from infertility treatments. This review will focus on the creation of parthenotes from clinically unusable oocytes for derivation and establishment of human parthenogenetic stem cell lines and their potential applications in regenerative medicine. PMID:26635881

  13. Parthenogenesis and Human Assisted Reproduction.

    PubMed

    Bos-Mikich, Adriana; Bressan, Fabiana F; Ruggeri, Rafael R; Watanabe, Yeda; Meirelles, Flávio V

    2016-01-01

    Parthenogenetic activation of human oocytes obtained from infertility treatments has gained new interest in recent years as an alternative approach to create embryos with no reproductive purpose for research in areas such as assisted reproduction technologies itself, somatic cell, and nuclear transfer experiments and for derivation of clinical grade pluripotent embryonic stem cells for regenerative medicine. Different activating methods have been tested on human and nonhuman oocytes, with varying degrees of success in terms of parthenote generation rates, embryo development stem cell derivation rates. Success in achieving a standardized artificial activation methodology for human oocytes and the subsequent potential therapeutic gain obtained from these embryos depends mainly on the availability of gametes donated from infertility treatments. This review will focus on the creation of parthenotes from clinically unusable oocytes for derivation and establishment of human parthenogenetic stem cell lines and their potential applications in regenerative medicine. PMID:26635881

  14. Geographical Database Integrity Validation

    NASA Technical Reports Server (NTRS)

    Jacobs, Derya; Kauffman, Paul; Blackstock, Dexter

    2000-01-01

    Airport Safety Modeling Data (ASMD) was developed at the request of a 1997 White House Conference on Aviation Safety and Security. Politicians, military personnel, commercial aircraft manufacturers and the airline industry attended the conference. The objective of the conference was to study the airline industry and make recommendations to improve safety and security. One of the topics discussed at the conference was the loss of situational awareness by aircraft pilots. Loss of situational awareness occurs when a pilot loses his geographic position during flight and can result in crashes into terrain and obstacles. It was recognized at the conference that aviation safety could be improved by reducing the loss of situational awareness. The conference advised that a system be placed in the airplane cockpit that would provide pilots with a visual representation of the terrain around airports. The system would prevent airline crashes during times of inclement weather and loss of situational awareness. The system must be based on accurate data that represents terrain around airports. The Department of Defense and the National Imagery and Mapping Agency (NIMA) released ASMD to be used for the development of a visual system for aircraft pilots. ASMD was constructed from NIMA digital terrain elevation data (DTED).

  15. International Refugees: A Geographical Perspective.

    ERIC Educational Resources Information Center

    Demko, George J.; Wood, William B.

    1987-01-01

    Examines the problem of international refugees from a geographical perspective. Focuses on sub-saharan Africa, Afghanistan, Central America, and southeast Asia. Concludes that geographers can and should use their skills and intellectual tools to address and help resolve this global problem. (JDH)

  16. Adaptive Cartography and Geographical Education

    ERIC Educational Resources Information Center

    Konecny, Milan; Stanek, Karel

    2010-01-01

    The article focuses on adaptive cartography and its potential for geographical education. After briefly describing the wider context of adaptive cartography, it is suggested that this new cartographic approach establishes new demands and benefits for geographical education, especially in offering the possibility for broader individual…

  17. Geographic latitude and prevalence of adolescent idiopathic scoliosis.

    PubMed

    Grivas, Theodoros B; Vasiliadis, Elias; Savvidou, Olga; Mouzakis, Vasilios; Koufopoulos, Georgios

    2006-01-01

    Adolescent Idiopathic Scoliosis (AIS) prevalence has been reported to be different in various geographic latitudes and demonstrates higher values in northern countries. A study on epidemiological reports from the literature was conducted to record the prevalence of AIS among the general population of boys and girls, aged 10-16 years old, in different geographic latitudes, in order to test the hypothesis that the prevalence of AIS among boys and girls is different in various geographic latitudes and to examine if there is a possible association between them. Seventeen peer-reviewed published papers reporting AIS prevalence in the general population of boys and girls from most geographic areas of the northern hemisphere were retrieved from the literature. The geographic latitude of each centre where a particular study was originated was documented. The statistical analysis included a linear regression forward modeling procedure of the AIS prevalence by latitude, weighted by sample size. According to the modelling of the data, a significant positive association between prevalence of AIS and latitude was found for girls (p<0.001), following a rather curvilinear trend, but not a significant positive association was found for boys (p<0.111). A positive association between prevalence of AIS and geographic latitude is reported only for girls in the present study. Prevalence of AIS in boys is not associated significantly with geographic latitude. This differing significant association implicates the possible role of environmental factors in the pathogenesis of AIS that may act in a different way between boys and girls.

  18. 33 CFR 165.8 - Geographic coordinates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Geographic coordinates. 165.8... Geographic coordinates. Geographic coordinates expressed in terms of latitude or longitude, or both, are not... 1983 (NAD 83), unless such geographic coordinates are expressly labeled NAD 83. Geographic...

  19. Idea and implementation studies of populating TOPO250 component with the data from TOPO10 - generalization of geographic information in the BDG database. (Polish Title: Koncepcja i studium implementacji procesu zasilania komponentu TOPO250 danymi TOPO10 - generalizacja informacji geograficznej w bazie danych BDG )

    NASA Astrophysics Data System (ADS)

    Olszewski, R.; Pillich-Kolipińska, A.; Fiedukowicz, A.

    2013-12-01

    Implementation of INSPIRE Directive in Poland requires not only legal transposition but also development of a number of technological solutions. The one of such tasks, associated with creation of Spatial Information Infrastructure in Poland, is developing a complex model of georeference database. Significant funding for GBDOT project enables development of the national basic topographical database as a multiresolution database (MRDB). Effective implementation of this type of database requires developing procedures for generalization of geographic information (generalization of digital landscape model - DLM), which, treating TOPO10 component as the only source for creation of TOPO250 component, will allow keeping conceptual and classification consistency between those database elements. To carry out this task, the implementation of the system's concept (prepared previously for Head Office of Geodesy and Cartography) is required. Such system is going to execute the generalization process using constrained-based modeling and allows to keep topological relationships between the objects as well as between the object classes. Full implementation of the designed generalization system requires running comprehensive tests which would help with its calibration and parameterization of the generalization procedures (related to the character of generalized area). Parameterization of this process will allow determining the criteria of specific objects selection, simplification algorithms as well as the operation order. Tests with the usage of differentiated, related to the character of the area, generalization process parameters become nowadays the priority issue. Parameters are delivered to the system in the form of XML files, which, with the help of dedicated tool, are generated from the spreadsheet files (XLS) filled in by user. Using XLS file makes entering and modifying the parameters easier. Among the other elements defined by the external parametric files there are

  20. The National Map - geographic names

    USGS Publications Warehouse

    Yost, Lou; Carswell, William J.

    2009-01-01

    The Geographic Names Information System (GNIS), developed by the U.S. Geological Survey (USGS) in cooperation with the U.S. Board on Geographic Names (BGN), contains information about the official names for places, features, and areas in the 50 States, the District of Columbia, the territories and outlying areas of the United States, including Antarctica. It is the geographic names component of The National Map. The BGN maintains working relationships with State names authorities to cooperate in achieving the standardization of geographic names. The GNIS contains records on more than 2 million geographic names in the United States - from populated places, schools, reservoirs, and parks to streams, valleys, springs, ridges, and every feature type except roads and highways. Entries include information such as the federally-recognized name and variant names and spellings for the feature; former names; the status of the name as determined by the BGN; county or counties in which each named feature is located; geographic coordinates that locate the approximate center of an aerial feature or the mouth and source of a linear feature, such as a stream; name of the cell of the USGS topographic map or maps on which the feature may appear; elevation figures derived from the National Elevation Dataset; bibliographic code for the source of the name; BGN decision dates and historical information are available for some features. Data from the GNIS are used for emergency preparedness, mapmaking, local and regional planning, service delivery routing, marketing, site selection, environmental analysis, genealogical research, and other applications.

  1. Ontology for cell-based geographic information

    NASA Astrophysics Data System (ADS)

    Zheng, Bin; Huang, Lina; Lu, Xinhai

    2009-10-01

    Inter-operability is a key notion in geographic information science (GIS) for the sharing of geographic information (GI). That requires a seamless translation among different information sources. Ontology is enrolled in GI discovery to settle the semantic conflicts for its natural language appearance and logical hierarchy structure, which are considered to be able to provide better context for both human understanding and machine cognition in describing the location and relationships in the geographic world. However, for the current, most studies on field ontology are deduced from philosophical theme and not applicable for the raster expression in GIS-which is a kind of field-like phenomenon but does not physically coincide to the general concept of philosophical field (mostly comes from the physics concepts). That's why we specifically discuss the cell-based GI ontology in this paper. The discussion starts at the investigation of the physical characteristics of cell-based raster GI. Then, a unified cell-based GI ontology framework for the recognition of the raster objects is introduced, from which a conceptual interface for the connection of the human epistemology and the computer world so called "endurant-occurrant window" is developed for the better raster GI discovery and sharing.

  2. Reproductive biology and species geographical distribution in the Melastomataceae: a survey based on New World taxa

    PubMed Central

    dos Santos, Ana Paula Milla; Fracasso, Carla Magioni; Luciene dos Santos, Mirley; Romero, Rosana; Sazima, Marlies; Oliveira, Paulo Eugênio

    2012-01-01

    distributed. This is, to a certain extent, similar to the geographical parthenogenesis pattern of temperate apomictics. PMID:22751617

  3. Evaluating geographic information systems technology

    USGS Publications Warehouse

    Guptill, Stephen C.

    1989-01-01

    Computerized geographic information systems (GISs) are emerging as the spatial data handling tools of choice for solving complex geographical problems. However, few guidelines exist for assisting potential users in identifying suitable hardware and software. A process to be followed in evaluating the merits of GIS technology is presented. Related standards and guidelines, software functions, hardware components, and benchmarking are discussed. By making users aware of all aspects of adopting GIS technology, they can decide if GIS is an appropriate tool for their application and, if so, which GIS should be used.

  4. Analysing surnames as geographic data.

    PubMed

    Cheshire, James

    2014-01-01

    With most surname research undertaken within the fields of anthropology and population genetics, geographers have overlooked surnames as a credible data source. In addition to providing a review of recent developments in surname analysis, this paper highlights areas where geographers can make important contributions to advancing surname research, both in terms of its quality and also its applications. The review discusses the emerging applications for surname research, not least in the mining of online data, and ends by suggesting three future research themes to ensure the building momentum of surname research continues to grow across disciplines. PMID:25020015

  5. Changes at the National Geographic Society

    ERIC Educational Resources Information Center

    Schwille, Kathleen

    2016-01-01

    For more than 125 years, National Geographic has explored the planet, unlocking its secrets and sharing them with the world. For almost thirty of those years, National Geographic has been committed to K-12 educators and geographic education through its Network of Alliances. As National Geographic begins a new chapter, they remain committed to the…

  6. 33 CFR 162.1 - General.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SAFETY INLAND WATERWAYS NAVIGATION REGULATIONS § 162.1 General. Geographic coordinates expressed in terms... horizontal datum is the North American Datum of 1983 (NAD 83), unless such geographic coordinates are expressly labeled NAD 83. Geographic coordinates without the NAD 83 reference may be plotted on maps...

  7. Geographic Inquiry into Global Issues.

    ERIC Educational Resources Information Center

    Hill, A. David

    1993-01-01

    Describes the background and development of the Geographic Inquiry into Global Issues (GIGI) project. Maintains that the secondary school lessons are designed to teach citizenship and critical thinking skills. Emphasizes that the pedagogical approach is founded on the inquiry approach. (CFR)

  8. Family Oriented Geographic Field Experience.

    ERIC Educational Resources Information Center

    Williams, Karen Ann Lalk

    This paper describes a program of geographic education through field experience trips for family groups. Developed at Delta College in Michigan, the approach is unique because it emphasizes learning experiences for families rather than for individual students. The family is interpreted to include nuclear families, single-parent families with…

  9. Territorial Decentration and Geographic Learning.

    ERIC Educational Resources Information Center

    Stoltman, Joseph P.

    Territorial decentration is a question of major significance to geographic educators. This paper reports the findings of a research project designed to determine the territorial decentration of an American sample of children. The primary purpose of the research was to determine if Piaget's territorial decentration stages are appropriate for…

  10. Geographical Knowledge of University Students.

    ERIC Educational Resources Information Center

    Wood, Robert W.; And Others

    In order to obtain information on the status of geographical knowledge possessed by University of South Dakota (Vermillion) students, a geography survey designed to determine specific knowledge about the locations of bodies of water, countries, and cities was conducted. One map was used for identifying cities, while the second was used for…

  11. Powerful Knowledge and Geographical Education

    ERIC Educational Resources Information Center

    Roberts, Margaret

    2014-01-01

    Michael Young has argued that pupils should be given access to "powerful knowledge." This article examines the extent to which his concept of powerful knowledge is applicable to geographical education, in particular to the study of urban geography. It explores the distinction Young makes between everyday and school knowledge, how this…

  12. Maryland Automated Geographic Information System

    NASA Technical Reports Server (NTRS)

    Thomas, E. L.

    1978-01-01

    A computer based system designed for storing geographic data in a consistent and coordinated manner is described. The data are stored, retrieved, and analyzed using a 400 km sq/acre cell. Stored information can be displayed on computer maps in a manner similar to standard map graphics. The data bank contains various information for performing land use analysis in a variety of areas.

  13. Geographical Concepts in Turkish Lullabys

    ERIC Educational Resources Information Center

    Çifçi, Taner

    2016-01-01

    In this study, a collection of lullabies which have an important place in Turkish culture and which form an important genre in folk literature are examined to find out distribution and presentation of geographical terms in the lullabies in this collection. In the study, 2480 lullabies in Turkish Lullabies which is one of the leading collections in…

  14. Assesing Geographic Isolation of the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    Orellana, D.; Smith, F.

    2016-06-01

    The Galapagos Archipelago is one of the most important ecological spots in the planet due its unique biodiversity, active geology, and relatively well-preserved ecosystems. These characteristics are strongly based on the geographical isolation of the islands. On the one hand this isolation allowed the evolution processes that gave the islands their international fame and on the other hand it kept them from major human impacts that affected the vast majority of the Earth's surface. Galapagos' geographical isolation is therefore of mayor value, but it is rapidly diminishing due to the increase of marine and air transportation among islands and with the rest of the world. This increased accessibility implies enhanced risks for the ecological dynamics on the archipelago (e.g. increased risk of biological invasions, uncontrolled tourism growth, more water and energy consumption). Here, we introduce a general accessibility model to assess geographical isolation of the Galapagos Islands. The model aims to characterize accessibility in terms of human mobility by evaluating travel time to each point of the archipelago using all available transportation modalities. Using a multi criteria cost surface for marine and land areas, we estimated travel time for each surface unit using the fastest route and mode of transportation available while considering several friction factors such as surface type, slope, infrastructure, transfer points, legal restrictions, and physical barriers. We created maps to evaluate the isolation of different islands and places, highlighting the potential risks for several habitats and ecosystems. The model can be used for research and decision-making regarding island conservation, such as estimating spreading paths for invasive species, informing decisions on tourism management, and monitoring isolation changes of sensitive ecosystems.

  15. Geographic Skills in the Social Studies, Grades 7-12.

    ERIC Educational Resources Information Center

    Leatherwood, Arthur K., Ed.; Porter, Jack W., Ed.

    This publication is designed to assist secondary level curriculum planners, teachers, and teacher educators in developing a social studies curriculum that includes geographic skills for students' development. The first section lists general student objectives in geography that are considered essential. The following six sections contain more in…

  16. [Peru: differential fertility by geographic regions and departments, 1975].

    PubMed

    1979-10-01

    Reproductive behavior in Peru is measured according to geographic region and department by means of general and age-specific fertility rates. The accuracy and completeness of data from the 1974-1976 National Demographic Survey and the 1972 census are compared. The impact on fertility of urbanization and of various other socioeconomic factors in the different departments of Peru is considered.

  17. Geographical Applications of Remote Sensing

    SciTech Connect

    Weng, Qihao; Zhou, Yuyu; Quattrochi, Dale

    2013-02-28

    Data and Information derived through Earth observation technology have been extensively used in geographic studies, such as in the areas of natural and human environments, resources, land use and land cover, human-environment interactions, and socioeconomic issues. Land-use and land-cover change (LULCC), affecting biodiversity, climate change, watershed hydrology, and other surface processes, is one of the most important research topics in geography.

  18. Geographic Information System Data Analysis

    NASA Technical Reports Server (NTRS)

    Billings, Chad; Casad, Christopher; Floriano, Luis G.; Hill, Tracie; Johnson, Rashida K.; Locklear, J. Mark; Penn, Stephen; Rhoulac, Tori; Shay, Adam H.; Taylor, Antone; Thorpe, Karina

    1995-01-01

    Data was collected in order to further NASA Langley Research Center's Geographic Information System(GIS). Information on LaRC's communication, electrical, and facility configurations was collected. Existing data was corrected through verification, resulting in more accurate databases. In addition, Global Positioning System(GPS) points were used in order to accurately impose buildings on digitized images. Overall, this project will help the Imaging and CADD Technology Team (ICTT) prove GIS to be a valuable resource for LaRC.

  19. Geographic names of the Antarctic

    USGS Publications Warehouse

    ,; ,; ,; ,; Alberts, Fred G.

    1995-01-01

    This gazetteer contains 12,710 names approved by the United States Board on Geographic Names and the Secretary of the Interior for features in Antarctica and the area extending northward to the Antarctic Convergence. Included in this geographic area, the Antarctic region, are the off-lying South Shetland Islands, the South Orkney Islands, the South Sandwich Islands, South Georgia, Bouvetøya, Heard Island, and the Balleny Islands. These names have been approved for use by U.S. Government agencies. Their use by the Antarctic specialist and the public is highly recommended for the sake of accuracy and uniformity. This publication, which supersedes previous Board gazetteers or lists for the area, contains names approved as recently as December 1994. The basic name coverage of this gazetteer corresponds to that of maps at the scale of 1:250,000 or larger for coastal Antarctica, the off-lying islands, and isolated mountains and ranges of the continent. Much of the interior of Antarctica is a featureless ice plateau. That area has been mapped at a smaller scale and is nearly devoid of toponyms. All of the names are for natural features, such as mountains, glaciers, peninsulas, capes, bays, islands, and subglacial entities. The names of scientific stations have not been listed alphabetically, but they may appear in the texts of some decisions. For the names of submarine features, reference should be made to the Gazetteer of Undersea Features, 4th edition, U.S. Board on Geographic Names, 1990.

  20. How a Geographer Looks at Globalism.

    ERIC Educational Resources Information Center

    Natoli, Salvatore J.

    1990-01-01

    Argues a global perspective is inherent to all geographic research and education. Quotes several influential geographers concerning their views on globalism and geography as a discipline. Examines geography's five fundamental themes and their applicability to a global perspective. Considers roles geographers can play in solving world environmental…

  1. Brief Report: Diminishing Geographic Variability in Autism Spectrum Disorders over Time?

    ERIC Educational Resources Information Center

    Hoffman, Kate; Vieira, Veronica M.; Daniels, Julie L.

    2014-01-01

    We investigated differences in the geographic distribution of autism spectrum disorders (ASD) over time in central North Carolina with data from the Autism and Developmental Disabilities Monitoring Network. Using generalized additive models and geographic information systems we produced maps of ASD risk in 2002-2004 and 2006-2008. Overall the risk…

  2. 24 CFR 599.103 - Geographic and population requirements for a nominated area.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 3 2012-04-01 2012-04-01 false Geographic and population... Requirements for Nomination of Renewal Communities § 599.103 Geographic and population requirements for a... part. (b) Population requirements—(1) In general. Except as provided in paragraph (b)(2) of...

  3. 24 CFR 599.103 - Geographic and population requirements for a nominated area.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 3 2011-04-01 2010-04-01 true Geographic and population... Requirements for Nomination of Renewal Communities § 599.103 Geographic and population requirements for a... part. (b) Population requirements—(1) In general. Except as provided in paragraph (b)(2) of...

  4. 24 CFR 599.103 - Geographic and population requirements for a nominated area.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 3 2014-04-01 2013-04-01 true Geographic and population... Requirements for Nomination of Renewal Communities § 599.103 Geographic and population requirements for a... part. (b) Population requirements—(1) In general. Except as provided in paragraph (b)(2) of...

  5. 24 CFR 599.103 - Geographic and population requirements for a nominated area.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Geographic and population... Requirements for Nomination of Renewal Communities § 599.103 Geographic and population requirements for a... part. (b) Population requirements—(1) In general. Except as provided in paragraph (b)(2) of...

  6. 24 CFR 599.103 - Geographic and population requirements for a nominated area.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 3 2013-04-01 2013-04-01 false Geographic and population... Requirements for Nomination of Renewal Communities § 599.103 Geographic and population requirements for a... part. (b) Population requirements—(1) In general. Except as provided in paragraph (b)(2) of...

  7. Geographic and temporal variation in moth chemical communication.

    PubMed

    Groot, Astrid T; Inglis, Olive; Bowdridge, Scott; Santangelo, Richard G; Blanco, Carlos; López, Juan D; Vargas, Antonio Terán; Gould, Fred; Schal, Coby

    2009-08-01

    In moth pheromone communication signals, both quantitative and qualitative intraspecific differences have been found across geographic regions. Such variation has generally been hypothesized to be due to selection, but evidence of genetic control of these differences is largely lacking. To explore the patterns of variation in pheromone signals, we quantified variation in the female sex pheromone blend and male responses of two closely related noctuid moth species in five different geographic regions for 2-3 consecutive years. We found significant variation in the ratios of sex pheromone blend components as well as in male response, not only between geographic regions but also within a region between consecutive years. The temporal variation was of a similar magnitude as the geographic variation. As far as we know, this is the first study reporting such temporal variation in moth chemical communication systems. The geographic variation seems to at least partly be controlled by genetic factors, and to be correlated with the quality of the local chemical environment. However, the pattern of temporal variation within populations suggests that optimization of the pheromonal signal also may be driven by within-generation physiological adjustments by the moths in response to their experience of the local chemical environment.

  8. Comparing categories among geographic ontologies

    NASA Astrophysics Data System (ADS)

    Kavouras, Marinos; Kokla, Margarita; Tomai, Eleni

    2005-03-01

    Numerous attempts have been made to generate semantic "mappings" between different ontologies, or create aligned/integrated ones. An essential step towards their success is the ability to compare the categories involved. This paper introduces a systematic methodology for comparing categories met in geographic ontologies. The methodology explores/extracts semantic information provided by categories' definitions. The first step towards this goal is the recognition of syntactic and lexical patterns in definitions, which help to identify (a) semantic properties such as purpose, location, cover, and (b) semantic relations such as hypernym, part of, has-parts, etc. At the second step, a similarity measure among categories is applied, in order to explore how (the) extracted properties and relations interrelate. This framework enables us to (a) better understand the impact of context in cross-ontology "mappings", (b) evaluate the "quality" of definitions as to whether they respect mere ontological aspects (such as unambiguous taxonomies), and (c) deal more effectively with the problem of semantic translation among geographic ontologies.

  9. Geographic profiling and animal foraging.

    PubMed

    Le Comber, Steven C; Nicholls, Barry; Rossmo, D Kim; Racey, Paul A

    2006-05-21

    Geographic profiling was originally developed as a statistical tool for use in criminal cases, particularly those involving serial killers and rapists. It is designed to help police forces prioritize lists of suspects by using the location of crime scenes to identify the areas in which the criminal is most likely to live. Two important concepts are the buffer zone (criminals are less likely to commit crimes in the immediate vicinity of their home) and distance decay (criminals commit fewer crimes as the distance from their home increases). In this study, we show how the techniques of geographic profiling may be applied to animal data, using as an example foraging patterns in two sympatric colonies of pipistrelle bats, Pipistrellus pipistrellus and P. pygmaeus, in the northeast of Scotland. We show that if model variables are fitted to known roost locations, these variables may be used as numerical descriptors of foraging patterns. We go on to show that these variables can be used to differentiate patterns of foraging in these two species.

  10. Geographic profiling and animal foraging.

    PubMed

    Le Comber, Steven C; Nicholls, Barry; Rossmo, D Kim; Racey, Paul A

    2006-05-21

    Geographic profiling was originally developed as a statistical tool for use in criminal cases, particularly those involving serial killers and rapists. It is designed to help police forces prioritize lists of suspects by using the location of crime scenes to identify the areas in which the criminal is most likely to live. Two important concepts are the buffer zone (criminals are less likely to commit crimes in the immediate vicinity of their home) and distance decay (criminals commit fewer crimes as the distance from their home increases). In this study, we show how the techniques of geographic profiling may be applied to animal data, using as an example foraging patterns in two sympatric colonies of pipistrelle bats, Pipistrellus pipistrellus and P. pygmaeus, in the northeast of Scotland. We show that if model variables are fitted to known roost locations, these variables may be used as numerical descriptors of foraging patterns. We go on to show that these variables can be used to differentiate patterns of foraging in these two species. PMID:16263134

  11. Investigation of Error Patterns in Geographical Databases

    NASA Technical Reports Server (NTRS)

    Dryer, David; Jacobs, Derya A.; Karayaz, Gamze; Gronbech, Chris; Jones, Denise R. (Technical Monitor)

    2002-01-01

    The objective of the research conducted in this project is to develop a methodology to investigate the accuracy of Airport Safety Modeling Data (ASMD) using statistical, visualization, and Artificial Neural Network (ANN) techniques. Such a methodology can contribute to answering the following research questions: Over a representative sampling of ASMD databases, can statistical error analysis techniques be accurately learned and replicated by ANN modeling techniques? This representative ASMD sample should include numerous airports and a variety of terrain characterizations. Is it possible to identify and automate the recognition of patterns of error related to geographical features? Do such patterns of error relate to specific geographical features, such as elevation or terrain slope? Is it possible to combine the errors in small regions into an error prediction for a larger region? What are the data density reduction implications of this work? ASMD may be used as the source of terrain data for a synthetic visual system to be used in the cockpit of aircraft when visual reference to ground features is not possible during conditions of marginal weather or reduced visibility. In this research, United States Geologic Survey (USGS) digital elevation model (DEM) data has been selected as the benchmark. Artificial Neural Networks (ANNS) have been used and tested as alternate methods in place of the statistical methods in similar problems. They often perform better in pattern recognition, prediction and classification and categorization problems. Many studies show that when the data is complex and noisy, the accuracy of ANN models is generally higher than those of comparable traditional methods.

  12. Geographic distance affects dispersal of the patchy distributed greater long-tailed hamster (Tscherskia triton).

    PubMed

    Xue, Huiliang; Zhong, Min; Xu, Jinhui; Xu, Laixiang

    2014-01-01

    Dispersal is a fundamental process in ecology influencing the genetic structure and the viability of populations. Understanding how variable factors influence the dispersal of the population is becoming an important question in animal ecology. To date, geographic distance and geographic barriers are often considered as main factors impacting dispersal, but their effects are variable depending on different conditions. In general, geographic barriers affect more significantly than geographic distance on dispersal. In rapidly expanding populations, however, geographic barriers have less effect on dispersal than geographic distance. The effects of both geographic distance and geographic barriers in low-density populations with patchy distributions are poorly understood. By using a panel of 10 microsatellite loci we investigated the genetic structure of three patchy-distributed populations of the Greater long-tailed hamster (Tscherskia triton) from Raoyang, Guan and Shunyi counties of the North China Plain. The results showed that (i) high genetic diversity and differentiation exist in three geographic populations with patchy distributions; (ii) gene flow occurs among these three populations with physical barriers of Beijing city and Hutuo River, which potentially restricted the dispersal of the animal; (iii) the gene flow is negatively correlated with the geographic distance, while the genetic distance shows the positive correlation. Our results suggest that the effect of the physical barriers is conditional-dependent, including barrier capacity or individual potentially dispersal ability. Geographic distance also acts as an important factor affecting dispersal for the patchy distributed geographic populations. So, gene flow is effective, even at relatively long distances, in balancing the effect of geographic barrier in this study. PMID:24911266

  13. Geographic spatial reasoning strategy based on ontology

    NASA Astrophysics Data System (ADS)

    Du, Xiaochu; Guo, Qingsheng; Wang, Quanfang

    2009-10-01

    Research on geographical spatial reasoning aims at expression of spatial relationships, geo-spatial reasoning rules and reasoning mechanism that could be used for geo-spatial knowledge discovery and spatial analysis. Spatial reasoning is intelligent spatial data processing technology in support of geo-spatial decision-making. Geographic ontology is clear formal definition of geographical concepts, which defines the basic terms and relations of these concepts, and the rules combining these terms and relationship. Therefore, it can well meet the formal knowledge representation requirement for geo-spatial reasoning that carry out reasoning by using geographic ontology. In this paper, methods of creating geographic ontology are discussed, and the rules based on spatial reasoning are summarized. Furthermore, a path query method based on geographic ontology is proposed, by creating a road ontology system and the corresponding administrative region ontology system, it can be used to solve large-scale spatial path query problem.

  14. The Oklahoma Geographic Information Retrieval System

    NASA Technical Reports Server (NTRS)

    Blanchard, W. A.

    1982-01-01

    The Oklahoma Geographic Information Retrieval System (OGIRS) is a highly interactive data entry, storage, manipulation, and display software system for use with geographically referenced data. Although originally developed for a project concerned with coal strip mine reclamation, OGIRS is capable of handling any geographically referenced data for a variety of natural resource management applications. A special effort has been made to integrate remotely sensed data into the information system. The timeliness and synoptic coverage of satellite data are particularly useful attributes for inclusion into the geographic information system.

  15. Interactive LORAN-C to geographic and geographic-to-LORAN-C computation

    NASA Technical Reports Server (NTRS)

    Piecuch, L. M.; Lilley, R. W.

    1977-01-01

    The LORAN program is stored in CMS disk files for use by Avionics Engineering Center terminal users. A CMS EXEC file named LORAN controls program operation. The user types LORAN and the program then prompts for data input and produces output on the terminal. The FORTRAN program refers to a disk file of LORAN master data giving station locations, coding delays, repetition rate and station pair identification letters. For Geographic-to-LORAN conversion, no iterative computations are required; the program is a straightforward coordinate conversion based upon the techniques described by the Navy. For LORAN-to-Geographic conversion, the original Navy program required a dead-reckoned position, near the actual unknown fix, to begin computations. No iteration was performed to obtain the LORAN fix, but internal program errors occurred at execution time if the dead-reckoned fix were displaced from the actual fix by more than a few minutes of latitude or longitude. In order to enhance usefulness of the program for the terminal user, an iterative routine was added which allows a single dead-reckoned position to be entered from the master data file for each LORAN chain. The results compare exactly with the LORAN-C navigation chart, and provide adequate benchmark data for general aviation flight planning and data analysis.

  16. Geographic Determinants of Chinese Urbanization

    NASA Astrophysics Data System (ADS)

    Mccord, G. C.; Christensen, P.

    2011-12-01

    In the first years of the 21st century, the human race became primarily urban for the first time in history. With countries like India and China rapidly undergoing structural change from rural agricultural-based economies to urbanized manufacturing- and service-based economies, knowing where the coming waves of urbanization will occur would be of interest for infrastructure planning and for modeling consequences for ecological systems. We employ spatial econometric methods (geographically weighted regression, spatial lag models, and spatial errors models) to estimate two determinants of urbanization in China. The first is the role of physical geography, measured as topography-adjusted distance to major ports and suitability of land for agriculture. The second is the spatial agglomeration effect, which we estimate with a spatial lag model. We find that Chinese urbanization between 1990 and 2000 exhibited important spatial agglomeration effects, as well as significant explanatory power of nearby agricultural suitability and distance to ports, both in a nationwide model and in a model of local regression estimates. These results can help predict the location of new Chinese urbanization, and imply that climate change-induced changes in agricultural potential can affect the spatial distribution of urban areas.

  17. Geographical epidemiology, spatial analysis and geographical information systems: a multidisciplinary glossary

    PubMed Central

    Rezaeian, Mohsen; Dunn, Graham; Leger, Selwyn St; Appleby, Louis

    2007-01-01

    We provide a relatively non‐technical glossary of terms and a description of the tools used in spatial or geographical epidemiology and associated geographical information systems. Statistical topics included cover adjustment and standardisation to allow for demographic and other background differences, data structures, data smoothing, spatial autocorrelation and spatial regression. We also discuss the rationale for geographical epidemiology and specific techniques such as disease clustering, disease mapping, ecological analyses, geographical information systems and global positioning systems. PMID:17234866

  18. Geographical Literacy and the Role of GIS.

    ERIC Educational Resources Information Center

    West, Bryan A.

    1999-01-01

    Demonstrates how Geographical Information Systems (GIS) can help develop student skills that enhance learning. Describes the application of GIS within secondary geography education, providing an example of its use at the Windaroo Valley State High School (Australia). Discusses GIS and geographic literacy. (CMK)

  19. Spatial relation query based on geographic ontology

    NASA Astrophysics Data System (ADS)

    Du, Chong; Xu, Jun; Zhang, Jing; Si, Wangli; Liu, Bao; Zhang, Dapeng

    2010-11-01

    The description of a spatial relation is the reflection of human's cognition of spatial objects. It is not only affected by topology and metric, but also affected by geographic semantics, such as the categories of geographic entities and contexts. Currently, the researches about language aspects of spatial relations mostly focus on natural-language formalization, parsing of query sentences, and natural-language query interface. However, geographic objects are not simple geometric points, lines or polygons. In order to get a sound answer according with human cognition in spatial relation queries, we have to take geographic semantics into account. In this paper, the functions of natural-language spatial terms are designed based on previous work on natural-language formalization and human-subject tests. Then, the paper builds a geographic knowledge base based on geographic ontology using Protégé for discriminating geographic semantics. Finally, using the geographic knowledge in the knowledge base, a prototype of a query system is implemented on GIS platform.

  20. Geographic differences in heart failure trials.

    PubMed

    Ferreira, João Pedro; Girerd, Nicolas; Rossignol, Patrick; Zannad, Faiez

    2015-09-01

    Randomized controlled trials (RCTs) are essential to develop advances in heart failure (HF). The need for increasing numbers of patients (without substantial cost increase) and generalization of results led to the disappearance of international boundaries in large RCTs. The significant geographic differences in patients' characteristics, outcomes, and, most importantly, treatment effect observed in HF trials have recently been highlighted. Whether the observed regional discrepancies in HF trials are due to trial-specific issues, patient heterogeneity, structural differences in countries, or a complex interaction between factors are the questions we propose to debate in this review. To do so, we will analyse and review data from HF trials conducted in different world regions, from heart failure with preserved ejection fraction (HF-PEF), heart failure with reduced ejection fraction (HF-REF), and acute heart failure (AHF). Finally, we will suggest objective and actionable measures in order to mitigate regional discrepancies in future trials, particularly in HF-PEF where prognostic modifying treatments are urgently needed and in which trials are more prone to selection bias, due to a larger patient heterogeneity.

  1. Cartographic services contract...for everything geographic

    USGS Publications Warehouse

    ,

    2003-01-01

    The U.S. Geological Survey's (USGS) Cartographic Services Contract (CSC) is used to award work for photogrammetric and mapping services under the umbrella of Architect-Engineer (A&E) contracting. The A&E contract is broad in scope and can accommodate any activity related to standard, nonstandard, graphic, and digital cartographic products. Services provided may include, but are not limited to, photogrammetric mapping and aerotriangulation; orthophotography; thematic mapping (for example, land characterization); analog and digital imagery applications; geographic information systems development; surveying and control acquisition, including ground-based and airborne Global Positioning System; analog and digital image manipulation, analysis, and interpretation; raster and vector map digitizing; data manipulations (for example, transformations, conversions, generalization, integration, and conflation); primary and ancillary data acquisition (for example, aerial photography, satellite imagery, multispectral, multitemporal, and hyperspectral data); image scanning and processing; metadata production, revision, and creation; and production or revision of standard USGS products defined by formal and informal specification and standards, such as those for digital line graphs, digital elevation models, digital orthophoto quadrangles, and digital raster graphics.

  2. Geographic differences in heart failure trials.

    PubMed

    Ferreira, João Pedro; Girerd, Nicolas; Rossignol, Patrick; Zannad, Faiez

    2015-09-01

    Randomized controlled trials (RCTs) are essential to develop advances in heart failure (HF). The need for increasing numbers of patients (without substantial cost increase) and generalization of results led to the disappearance of international boundaries in large RCTs. The significant geographic differences in patients' characteristics, outcomes, and, most importantly, treatment effect observed in HF trials have recently been highlighted. Whether the observed regional discrepancies in HF trials are due to trial-specific issues, patient heterogeneity, structural differences in countries, or a complex interaction between factors are the questions we propose to debate in this review. To do so, we will analyse and review data from HF trials conducted in different world regions, from heart failure with preserved ejection fraction (HF-PEF), heart failure with reduced ejection fraction (HF-REF), and acute heart failure (AHF). Finally, we will suggest objective and actionable measures in order to mitigate regional discrepancies in future trials, particularly in HF-PEF where prognostic modifying treatments are urgently needed and in which trials are more prone to selection bias, due to a larger patient heterogeneity. PMID:26198782

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

    PubMed Central

    Park, Jong Heon; Hwang, Kyosang; Lee, Taesik

    2016-01-01

    Objectives: We aimed to evaluate the effect of geographic units of analysis on measuring geographic variation in medical services utilization. For this purpose, we compared geographic variations in the rates of eight major procedures in administrative units (districts) and new areal units organized based on the actual health care use of the population in Korea. Methods: To compare geographic variation in geographic units of analysis, we calculated the age–sex standardized rates of eight major procedures (coronary artery bypass graft surgery, percutaneous transluminal coronary angioplasty, surgery after hip fracture, knee-replacement surgery, caesarean section, hysterectomy, computed tomography scan, and magnetic resonance imaging scan) from the National Health Insurance database in Korea for the 2013 period. Using the coefficient of variation, the extremal quotient, and the systematic component of variation, we measured geographic variation for these eight procedures in districts and new areal units. Results: Compared with districts, new areal units showed a reduction in geographic variation. Extremal quotients and inter-decile ratios for the eight procedures were lower in new areal units. While the coefficient of variation was lower for most procedures in new areal units, the pattern of change of the systematic component of variation between districts and new areal units differed among procedures. Conclusions: Geographic variation in medical service utilization could vary according to the geographic unit of analysis. To determine how geographic characteristics such as population size and number of geographic units affect geographic variation, further studies are needed. PMID:27499165

  4. Larval ecology, geographic range, and species survivorship in Cretaceous mollusks: organismic versus species-level explanations.

    PubMed

    Jablonski, David; Hunt, Gene

    2006-10-01

    The observation that geographic range size in Cretaceous mollusks is correlated with species survivorship and is heritable at the species level has figured repeatedly in discussions of species selection over the past two decades. However, some authors have suggested that the relationship between mode of larval development and geographic range supports the reduction of this example to selection on organismic properties. Our reanalysis of Jablonski's work on heritability at the species level finds that geographic range is significantly heritable (using a randomization test) in both bivalves and gastropods, even within a single larval mode. Further, generalized linear models show that geographic range size is more important than larval mode in predicting extinction probability in both gastropods and bivalves. These results reaffirm the role and heritability of geographic range as a species-level property that can promote species selection; the model-based approach applied here may help to operationalize "screening off " and related approaches to evaluating hierarchical explanations in evolution.

  5. Usability of geographic information -- factors identified from qualitative analysis of task-focused user interviews.

    PubMed

    Harding, Jenny

    2013-11-01

    Understanding user needs for geographic information and the factors which influence the usability of such information in diverse user contexts is an essential part of user centred development of information products. There is relatively little existing research focused on the design and usability of information products in general. This paper presents a research approach based on semi structured interviews with people working with geographic information on a day to day basis, to establish a reference base of qualitative data on user needs for geographic information with respect to context of use. From this reference data nine key categories of geographic information usability are identified and discussed in the context of limited existing research concerned with geographic information usability.

  6. Health Based Geographic Information Systems (GIS) and their Applications.

    PubMed

    Fradelos, Evangelos C; Papathanasiou, Ioanna V; Mitsi, Dimitra; Tsaras, Konstantinos; Kleisiaris, Christos F; Kourkouta, Lambrini

    2014-12-01

    Medical researches as well as the study of the Earth's surface, better still, geography are interlinked with each other; their relationship dates from antiquity. The science of Geographic Information Systems and, by extension, Geomatics engineering belongs to a discipline which is constantly developing at a global level. This sector has many applications regarding medical / epidemiological research and generally, the social sciences. Furthermore, this discipline may act as a decision making tool in the healthcare sector and it might contribute to the formulation of policies into the healthcare sector. The use of GIS so as to solve public health issues has an exponential increase and has been vital to the understanding and treatment of health problems in different geographic areas. In recent years, the use of various information technology services and software has lead health professionals to work more effectively.

  7. Health Based Geographic Information Systems (GIS) and their Applications

    PubMed Central

    Fradelos, Evangelos C.; Papathanasiou, Ioanna V.; Mitsi, Dimitra; Tsaras, Konstantinos; Kleisiaris, Christos F.; Kourkouta, Lambrini

    2014-01-01

    Medical researches as well as the study of the Earth’s surface, better still, geography are interlinked with each other; their relationship dates from antiquity. The science of Geographic Information Systems and, by extension, Geomatics engineering belongs to a discipline which is constantly developing at a global level. This sector has many applications regarding medical / epidemiological research and generally, the social sciences. Furthermore, this discipline may act as a decision making tool in the healthcare sector and it might contribute to the formulation of policies into the healthcare sector. The use of GIS so as to solve public health issues has an exponential increase and has been vital to the understanding and treatment of health problems in different geographic areas. In recent years, the use of various information technology services and software has lead health professionals to work more effectively. PMID:25684850

  8. Layers of Information: Geographic Information Systems (GIS).

    ERIC Educational Resources Information Center

    Lucking, Robert A.; Christmann, Edwin P.

    2003-01-01

    Describes the Geographic Information System (GIS) which is capable of storing, manipulating, and displaying data allowing students to explore complex relationships through scientific inquiry. Explains applications of GIS in middle school classrooms and includes assessment strategies. (YDS)

  9. Geographic and environmental factors in pediatric cancer

    SciTech Connect

    Gordis, L.

    1986-07-15

    It is important to determine the relative contributions of genetic and environmental factors to the etiology of childhood cancer in order to elucidate the pathogenic mechanisms involved and to develop effective means of primary prevention. Geographic differences in cancer incidence as well as changes in incidence over calendar time have long been used to generate clues to possible etiologic agents. The important role of genetic factors in childhood cancer is clear, and is exemplified by the observations in retinoblastoma. The importance of the contributions of environmental factors in general and of specific factors in particular, to the etiology of cancers in children, has proven more difficult to determine. A variety of environmental factors have been implicated to varying degrees in the etiology of different childhood cancers. These factors include physical agents such as radiation, chemical agents such as nitrosamines, and organic solvents, and infectious agents such as the Epstein-Barr virus. The observations that certain compounds may act as teratogens when a prenatal exposure occurs early in pregnancy and as carcinogens when the exposure occurs late in pregnancy, suggests that there may be a continuum of teratogenesis and carcinogenesis. This finding has major implications for the possible biologic mechanisms that could be involved in childhood cancers and for the design of future research of their etiology and prevention. The etiology of childhood cancer should be viewed as an interaction of environmental factors to which the child or his parent were exposed together with varying degrees of genetically determined susceptibility of the child to the carcinogenic effects of these factors.

  10. The Geographic Scale of Metropolitan Racial Segregation

    PubMed Central

    REARDON, SEAN F.; MATTHEWS, STEPHEN A.; O’SULLIVAN, DAVID; LEE, BARRETT A.; FIREBAUGH, GLENN; FARRELL, CHAD R.; BISCHOFF, KENDRA

    2008-01-01

    This article addresses an aspect of racial residential segregation that has been largely ignored in prior work: the issue of geographic scale. In some metropolitan areas, racial groups are segregated over large regions, with predominately white regions, predominately black regions, and so on, whereas in other areas, the separation of racial groups occurs over much shorter distances. Here we develop an approach—featuring the segregation profile and the corresponding macro/micro segregation ratio—that offers a scale-sensitive alternative to standard methodological practice for describing segregation. Using this approach, we measure and describe the geographic scale of racial segregation in the 40 largest U.S. metropolitan areas in 2000. We find considerable heterogeneity in the geographic scale of segregation patterns across both metropolitan areas and racial groups, a heterogeneity that is not evident using conventional “aspatial” segregation measures. Moreover, because the geographic scale of segregation is only modestly correlated with the level of segregation in our sample, we argue that geographic scale represents a distinct dimension of residential segregation. We conclude with a brief discussion of the implications of our findings for investigating the patterns, causes, and consequences of residential segregation at different geographic scales. PMID:18939658

  11. The Needs and Scope of Geographic Education in America

    ERIC Educational Resources Information Center

    Elam, William W.

    1974-01-01

    Geographic concepts are central to environmental education and place geographers in a position to coordinate environmental education. Geographers are admonished to assume that responsibility as they carry out their roles as educators. (JH)

  12. 3. Historic American Buildings Survey Photocopy, National Geographic Society Photograph, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Historic American Buildings Survey Photocopy, National Geographic Society Photograph, 1971 Courtesy, National Geographic Society LIBRARY, 1971 - Townsend House, 2121 Massachusetts Avenue Northwest, Washington, District of Columbia, DC

  13. Introductory comments on the USGS geographic applications program

    NASA Technical Reports Server (NTRS)

    Gerlach, A. C.

    1970-01-01

    The third phase of remote sensing technologies and potentials applied to the operations of the U.S. Geological Survey is introduced. Remote sensing data with multidisciplinary spatial data from traditional sources is combined with geographic theory and techniques of environmental modeling. These combined imputs are subject to four sequential activities that involve: (1) thermatic mapping of land use and environmental factors; (2) the dynamics of change detection; (3) environmental surveillance to identify sudden changes and general trends; and (4) preparation of statistical model and analytical reports. Geography program functions, products, clients, and goals are presented in graphical form, along with aircraft photo missions, geography test sites, and FY-70.

  14. The Value of Open Geographical Data - The Danish Case

    NASA Astrophysics Data System (ADS)

    Colding, T. S.; Folner, M.; Krarup, S.; Kongsbak, J.

    2013-12-01

    Good basic data for everyone is part of the common public-sector digitization strategy for 2011 to 2015. The vision is that basic data is to be the high-quality common foundation for public sector administration; efficiently updated at one place, and used by everyone - including the private sector. Open basic data will benefit public-sector efficiency as well as innovation and value creation by Danish society in general. With basic data as a new digital raw material, commercial products can be developed and public information and services can be improved, providing for greater insight and stronger democracy. On the first of January 2013 Denmark released this digital raw material. As a general rule, all basic data is to be made freely available to all public authorities, private businesses and individuals. This makes basic data a common digital resource, which can be exploited freely for commercial as well as non-commercial purposes. A positive business case contributed in convincing Danish politicians to approve the basic data program. Once the initiatives have been fully implemented, the revenues for society are expected to be approx. DKK 800 million annually. Private-sector revenues will be up to DKK half a billion annually, and it is expected that e.g. the real estate, insurance, financial, and telecom sectors, as well as GPS (sat-nav) manufacturers, public companies and entrepreneurs will be among those to benefit hugely from the initiatives. The financial gain for the private sector of open geographical data alone is expected to be approx. 100 million DKK annually. As part of the Basic data program The Danish Geodata Agency (Ministry of the Environment) gave free access to all topographic data, cadastral maps and Digital Elevation Model on Jan. 1st, 2013. The Danish Geodata Agency has decided to measure the effect of the open geographic data in the public sector (efficiency) and in the private sector (growth). The effect will be measured by using reference

  15. An intelligent method for geographic Web search

    NASA Astrophysics Data System (ADS)

    Mei, Kun; Yuan, Ying

    2008-10-01

    While the electronically available information in the World-Wide Web is explosively growing and thus increasing, the difficulty to find relevant information is also increasing for search engine user. In this paper we discuss how to constrain web queries geographically. A number of search queries are associated with geographical locations, either explicitly or implicitly. Accurately and effectively detecting the locations where search queries are truly about has huge potential impact on increasing search relevance, bringing better targeted search results, and improving search user satisfaction. Our approach focus on both in the way geographic information is extracted from the web and, as far as we can tell, in the way it is integrated into query processing. This paper gives an overview of a spatially aware search engine for semantic querying of web document. It also illustrates algorithms for extracting location from web documents and query requests using the location ontologies to encode and reason about formal semantics of geographic web search. Based on a real-world scenario of tourism guide search, the application of our approach shows that the geographic information retrieval can be efficiently supported.

  16. Geographical distribution of the dermatophytes: a review.

    PubMed Central

    Philpot, C. M.

    1978-01-01

    In these days of rapid transit from continent to continent, and the increasing mobility of people, agents of disease are no longer geographically restricted. Disease contracted half way across the world may become manifest in a country in which the pathogen is not normally found. Thus knowledge of the geographical distribution of pathogens becomes increasingly important when a diagnosis is being made. This is as true of ringworm fungi as of any other group of microorganisms. In the last 12 years, in the Mycological Reference Laboratory, an increasing number of exotic dermatophytes have been seen, related in part at least to the great increase in the number of non-British residents. Not all species of dermatophytes are cosmopolitan in their distribution throughout the world. While some have been recorded from every continent, others have geographically limited areas of greater or lesser extent. Surveys taken at intervals in a country may show a rise and fall in occurrence of several species as habits change, populations move and medical facilities became increasingly well-distributed. There have been few geographical surveys of ringworm fungi that have covered the world. Ajello (1960, 1974) has reviewed the individual species with regard to geographical location, while Vanbreuseghem & de Vroey (1970) attempted to estimate the relative importance of the various species in terms of numbers of isolations reported. This paper therefore reviews the world dermatophyte flora in terms of the dominant agents in the various countries, and some of the changes that have been recorded. PMID:75918

  17. A Framework for Geographic Object-Based Image Analysis (GEOBIA) based on geographic ontology

    NASA Astrophysics Data System (ADS)

    Gu, H. Y.; Li, H. T.; Yan, L.; Lu, X. J.

    2015-06-01

    GEOBIA (Geographic Object-Based Image Analysis) is not only a hot topic of current remote sensing and geographical research. It is believed to be a paradigm in remote sensing and GIScience. The lack of a systematic approach designed to conceptualize and formalize the class definitions makes GEOBIA a highly subjective and difficult method to reproduce. This paper aims to put forward a framework for GEOBIA based on geographic ontology theory, which could implement "Geographic entities - Image objects - Geographic objects" true reappearance. It consists of three steps, first, geographical entities are described by geographic ontology, second, semantic network model is built based on OWL(ontology web language), at last, geographical objects are classified with decision rule or other classifiers. A case study of farmland ontology was conducted for describing the framework. The strength of this framework is that it provides interpretation strategies and global framework for GEOBIA with the property of objective, overall, universal, universality, etc., which avoids inconsistencies caused by different experts' experience and provides an objective model for mage analysis.

  18. Pre-Service Geography Teachers' Confidence in Geographical Subject Matter Knowledge and Teaching Geographical Skills

    ERIC Educational Resources Information Center

    Harte, Wendy; Reitano, Paul

    2015-01-01

    This research tracked the confidence of 16 undergraduate and postgraduate pre-service geography teachers as they completed a single semester, senior phase geography curriculum course. The study focused specifically on the pre-service teachers' confidence in geographical subject matter knowledge and their confidence in teaching geographical skills.…

  19. Geographic variation in marine turtle fibropapillomatosis

    USGS Publications Warehouse

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

    2005-01-01

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

  20. Geographic information system/watershed model interface

    USGS Publications Warehouse

    Fisher, Gary T.

    1989-01-01

    Geographic information systems allow for the interactive analysis of spatial data related to water-resources investigations. A conceptual design for an interface between a geographic information system and a watershed model includes functions for the estimation of model parameter values. Design criteria include ease of use, minimal equipment requirements, a generic data-base management system, and use of a macro language. An application is demonstrated for a 90.1-square-kilometer subbasin of the Patuxent River near Unity, Maryland, that performs automated derivation of watershed parameters for hydrologic modeling.

  1. Geographical variation in Plasmodium vivax relapse

    PubMed Central

    2014-01-01

    Background Plasmodium vivax has the widest geographic distribution of the human malaria parasites and nearly 2.5 billion people live at risk of infection. The control of P. vivax in individuals and populations is complicated by its ability to relapse weeks to months after initial infection. Strains of P. vivax from different geographical areas are thought to exhibit varied relapse timings. In tropical regions strains relapse quickly (three to six weeks), whereas those in temperate regions do so more slowly (six to twelve months), but no comprehensive assessment of evidence has been conducted. Here observed patterns of relapse periodicity are used to generate predictions of relapse incidence within geographic regions representative of varying parasite transmission. Methods A global review of reports of P. vivax relapse in patients not treated with a radical cure was conducted. Records of time to first P. vivax relapse were positioned by geographic origin relative to expert opinion regions of relapse behaviour and epidemiological zones. Mixed-effects meta-analysis was conducted to determine which geographic classification best described the data, such that a description of the pattern of relapse periodicity within each region could be described. Model outputs of incidence and mean time to relapse were mapped to illustrate the global variation in relapse. Results Differences in relapse periodicity were best described by a historical geographic classification system used to describe malaria transmission zones based on areas sharing zoological and ecological features. Maps of incidence and time to relapse showed high relapse frequency to be predominant in tropical regions and prolonged relapse in temperate areas. Conclusions The results indicate that relapse periodicity varies systematically by geographic region and are categorized by nine global regions characterized by similar malaria transmission dynamics. This indicates that relapse may be an adaptation evolved to

  2. Enhancing robustness and immunization in geographical networks

    SciTech Connect

    Huang Liang; Yang Kongqing; Yang Lei

    2007-03-15

    We find that different geographical structures of networks lead to varied percolation thresholds, although these networks may have similar abstract topological structures. Thus, strategies for enhancing robustness and immunization of a geographical network are proposed. Using the generating function formalism, we obtain an explicit form of the percolation threshold q{sub c} for networks containing arbitrary order cycles. For three-cycles, the dependence of q{sub c} on the clustering coefficients is ascertained. The analysis substantiates the validity of the strategies with analytical evidence.

  3. Location of geographical objects in crisis situations

    NASA Astrophysics Data System (ADS)

    Rybansky, M.; Kratochvil, V.

    2014-02-01

    This article summarizes the various expressions of object positioning using different coordinate data and different methods, such as use of maps, exploiting the properties of digital Global System for Mobile Communications (GSM) networks, Global Navigational Satellite Systems (GNSS), Inertial Navigation Systems (INS), Inertial Measurement Systems (IMS), hybrid methods and non-contact (remote sensing) methods; all with varying level of accuracy. Furthermore, the article describes some geographical identifiers and verbal means to describe location of geographical objects such as settlements, rivers, forest, roads, etc. All of the location methods have some advantages and disadvantages, especially in emergency situations, when usually the crisis management has a lack of time in a decision process.

  4. General Dentist

    MedlinePlus

    ... to your desktop! more... What Is a General Dentist? Article Chapters What Is a General Dentist? General ... Reviewed: January 2012 ?xml:namespace> Related Articles: General Dentists FAGD and MAGD: What Do These Awards Mean? ...

  5. Agricultural Turns, Geographical Turns: Retrospect and Prospect

    ERIC Educational Resources Information Center

    Morris, Carol; Evans, Nick

    2004-01-01

    It is accepted that British rural geography has actively engaged with the "cultural turn", leading to a resurgence of research within the sub-discipline. However, a reading of recent reviews suggests that the cultural turn has largely, if not completely, bypassed those geographers interested in the agricultural sector. Farming centred engagements…

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

    PubMed

    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.

  7. Mapware: Educational Applications of Geographic Information Systems.

    ERIC Educational Resources Information Center

    Tinker, Robert F.

    1992-01-01

    Analyzes the applicability to mathematics and science education of geographic information systems. Gives examples of possible applications involving aerosol detection in the atmosphere, verification of satellite images, and the Kidnet Project. Sketches out a research agenda and describes needed characteristics of the software when applied to…

  8. Diversity, Disability, and Geographic Digital Divide

    ERIC Educational Resources Information Center

    Sumari, Melati; Carr, Erika; Ndebe-Ngovo, Manjerngie

    2006-01-01

    The phenomenon called digital divide was the focus of this paper. Diversity, disability, and geographical digital divide were relevant to this collaborative project. An extensive review of the literature was conducted for the completion of this project. The evidence for the digital divide in terms of race, level of education, and gender in the…

  9. Teaching Geographic Concepts through Fieldwork and Competition

    ERIC Educational Resources Information Center

    Hupy, Joseph P.

    2011-01-01

    This article describes the benefits of combining field-based learning within the context of a competitive setting in the geography curriculum. Findings and data are presented based on experiences gathered from teaching an upper-level university geography course that combined geographic techniques and theory into a game of capture-the-flag.…

  10. Representing Historical Knowledge in Geographic Information Systems

    ERIC Educational Resources Information Center

    Grossner, Karl Eric

    2010-01-01

    A growing number of historical scholars in social science and humanities fields are using geographic information systems (GIS) to help investigate spatial questions and map their findings. The nature of historical data and historiographic practices present several challenges in using GIS that have been addressed only partially to date. For…

  11. Promoting Geographic Information System Usage across Campus

    ERIC Educational Resources Information Center

    Spiegel, Shaun; Kinikin, Janae

    2004-01-01

    In this article the authors discuss how they implemented and promoted Geographic Information System (GIS) applications at Weber State University (WSU), a four-year public institution with two campuses. GIS is a type of computer system made of hardware, software, and data that allows the mapping of spatially related layers that have a common…

  12. The Geographic Polarization of American Voters

    ERIC Educational Resources Information Center

    Pearson-Merkowitz, Shanna; Lang, Corey

    2016-01-01

    For the past two decades, the presidency and both houses of Congress have been hotly contested by the two major political parties. Yet, geographically, the United States seems to be increasingly marked by "red" areas where the Democratic Party lacks any ability to even dream of winning office and "blue" areas where the…

  13. Cartography, Geographic Information, and Public Policy.

    ERIC Educational Resources Information Center

    Monmonier, Mark S.

    1982-01-01

    Cartography is undergoing a digital transition with geographic data becoming available in machine-readable form and with the diminishing need to draw and print maps in order to communicate information. This automation will force cartographers to concentrate upon the institutional aspects of information management. Implications for geographic…

  14. Interactive Computer Programs for Geographic Education.

    ERIC Educational Resources Information Center

    Lougeay, Cheryl

    Examples of computer programs illustrate how instructors can introduce students to geographic concepts and models while creating a thinking environment in the classroom. The programs are designed to assist students in computational tasks and to provide both graphic and numeric output which will be stimulating. A population pyramid program…

  15. Geographical Education and Film: An Experimental Course.

    ERIC Educational Resources Information Center

    Jenkins, Alan; Youngs, Martyn

    1983-01-01

    A course to make college level geography students (London School of Economics) aware of the nature of film and television and to indicate the importance of these media to the geographer is described. The course emphasizes activities and involvement so that students can develop judgments about how film and television shape reality. (KC)

  16. Validating a Geographical Image Retrieval System.

    ERIC Educational Resources Information Center

    Zhu, Bin; Chen, Hsinchun

    2000-01-01

    Summarizes a prototype geographical image retrieval system that demonstrates how to integrate image processing and information analysis techniques to support large-scale content-based image retrieval. Describes an experiment to validate the performance of this image retrieval system against that of human subjects by examining similarity analysis…

  17. Geographic Education in Turkish High Schools

    ERIC Educational Resources Information Center

    Tas, Halil I.

    2005-01-01

    This paper presents a review of geographic curricula, teaching methods, materials and assessments in Turkish high schools. Geopolitics and political instability have contributed to large fluctuations in emphasis on geography in Turkish education and have also affected the content of the geography curriculum.

  18. Displaying Geographically-Based Domestic Statistics

    NASA Technical Reports Server (NTRS)

    Quann, J.; Dalton, J.; Banks, M.; Helfer, D.; Szczur, M.; Winkert, G.; Billingsley, J.; Borgstede, R.; Chen, J.; Chen, L.; Fuh, J.; Cyprych, E.

    1982-01-01

    Decision Information Display System (DIDS) is rapid-response information-retrieval and color-graphics display system. DIDS transforms tables of geographically-based domestic statistics (such as population or unemployment by county, energy usage by county, or air-quality figures) into high-resolution, color-coded maps on television display screen.

  19. Geographical Study of American Blues Culture

    ERIC Educational Resources Information Center

    Strait, John B.

    2010-01-01

    Music is not often utilized in teaching geography, despite the fact that many scholars orient their research around analyzing both the historical and spatial dimensions of musical expression. This article reports on the use of a teaching module that utilizes blues culture as a lens to understand the geographical history of the United States. The…

  20. Frontiers in Geographical Teaching. Second Edition.

    ERIC Educational Resources Information Center

    Chorley, Richard J., Ed.; Haggett, Peter, Ed.

    Composed of three parts, "Concepts,""Techniques," and "Teaching," this volume of essays by British geographers emerged from the editors' geography education courses and symposia at Cambridge University. It is addressed to two questions: what is happening in geography? and, what impact does this have on school geography? "Concepts" has seven essays…

  1. Science Fiction for Geographers: Selected Works.

    ERIC Educational Resources Information Center

    Elbow, Gary S.; Martinson, Tom L.

    1980-01-01

    Explains how college level teachers of geography can use works of science fiction to help students understand geographical settings and create impressionistic pictures of a given region in their minds. Particular areas in which science fiction is useful include invented terrestrial landscapes, specialized extraterrestrial landscapes, disaster…

  2. Enhancing Geographic Learning and Literacy through Filmmaking

    ERIC Educational Resources Information Center

    Dando, Christina E.; Chadwick, Jacob J.

    2014-01-01

    In this media-saturated society, students need to think more critically about the media they encounter and that they are producing. Through filmmaking, students can link geographic theory and the real world, bridging the distance from readings/lectures/discussions to the geography on the ground, making the abstract concrete. But constructing films…

  3. The Geographic Distribution of Indochinese Refugees.

    ERIC Educational Resources Information Center

    Forbes, Susan

    This paper presents information regarding the geographic distribution of Indochinese refugees in the United States and how it compares to that of the overall U.S. population and the non-refugee legal immigrant population. The following information is reported: Seventy percent of all Indochinese refugees currently reside in 10 States, with…

  4. Threading One's Way Through the Geographic Region.

    ERIC Educational Resources Information Center

    Thomas, Paul F.

    1982-01-01

    Designed for students in grades 7 through 12, the paper presents illustrative resource materials for teaching concepts related to geographic regions. Emphasis is on giving students an understanding of the interrelationship between regional characteristics and human behavior. The paper introduces students to the following notions: environmental…

  5. Geography and Geographical Information Science: Interdisciplinary Integrators

    ERIC Educational Resources Information Center

    Ellul, Claire

    2015-01-01

    To understand how Geography and Geographical Information Science (GIS) can contribute to Interdisciplinary Research (IDR), it is relevant to articulate the differences between the different types of such research. "Multidisciplinary" researchers work in a "parallel play" mode, completing work in their disciplinary work streams…

  6. Teaching Geographic Field Methods Using Paleoecology

    ERIC Educational Resources Information Center

    Walsh, Megan K.

    2014-01-01

    Field-based undergraduate geography courses provide numerous pedagogical benefits including an opportunity for students to acquire employable skills in an applied context. This article presents one unique approach to teaching geographic field methods using paleoecological research. The goals of this course are to teach students key geographic…

  7. Geographical and Environmental Education in Albania

    ERIC Educational Resources Information Center

    Hall, Derek

    2004-01-01

    Drawing on a wide range of secondary and primary materials as well as personal experience of Albania dating from the 1970s to the present day, this paper describes and critically evaluates current geographical and environmental education in Albania in relation to three dimensions: (1) the changing nature of the curriculum over the past 20 years;…

  8. Geographic variation in gorilla limb bones.

    PubMed

    Jabbour, Rebecca S; Pearman, Tessa L

    2016-06-01

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

  9. Geographic variation in gorilla limb bones.

    PubMed

    Jabbour, Rebecca S; Pearman, Tessa L

    2016-06-01

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

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

    PubMed Central

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

    2011-01-01

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

  11. Methodology for classification of geographical features with remote sensing images: Application to tidal flats

    NASA Astrophysics Data System (ADS)

    Revollo Sarmiento, G. N.; Cipolletti, M. P.; Perillo, M. M.; Delrieux, C. A.; Perillo, Gerardo M. E.

    2016-03-01

    Tidal flats generally exhibit ponds of diverse size, shape, orientation and origin. Studying the genesis, evolution, stability and erosive mechanisms of these geographic features is critical to understand the dynamics of coastal wetlands. However, monitoring these locations through direct access is hard and expensive, not always feasible, and environmentally damaging. Processing remote sensing images is a natural alternative for the extraction of qualitative and quantitative data due to their non-invasive nature. In this work, a robust methodology for automatic classification of ponds and tidal creeks in tidal flats using Google Earth images is proposed. The applicability of our method is tested in nine zones with different morphological settings. Each zone is processed by a segmentation stage, where ponds and tidal creeks are identified. Next, each geographical feature is measured and a set of shape descriptors is calculated. This dataset, together with a-priori classification of each geographical feature, is used to define a regression model, which allows an extensive automatic classification of large volumes of data discriminating ponds and tidal creeks against other various geographical features. In all cases, we identified and automatically classified different geographic features with an average accuracy over 90% (89.7% in the worst case, and 99.4% in the best case). These results show the feasibility of using freely available Google Earth imagery for the automatic identification and classification of complex geographical features. Also, the presented methodology may be easily applied in other wetlands of the world and perhaps employing other remote sensing imagery.

  12. Knowing what and where: TMS evidence for the dual neural basis of geographical knowledge

    PubMed Central

    Hoffman, Paul; Crutch, Sebastian

    2016-01-01

    All animals acquire knowledge about the topography of their immediate environment through direct exploration. Uniquely, humans also acquire geographical knowledge indirectly through exposure to maps and verbal information, resulting in a rich database of global geographical knowledge. We used transcranial magnetic stimulation to investigate the structure and neural basis of this critical but poorly understood component of semantic knowledge. Participants completed tests of geographical knowledge that probed either information about spatial locations (e.g., France borders Spain) or non-spatial taxonomic information (e.g., France is a country). TMS applied to the anterior temporal lobe, a region that codes conceptual knowledge for words and objects, had a general disruptive effect on the geographical tasks. In contrast, stimulation of the intraparietal sulcus (IPS), a region involved in the coding of spatial and numerical information, had a highly selective effect on spatial geographical decisions but no effect on taxonomic judgements. Our results establish that geographical concepts lie at the intersection of two distinct neural representation systems, and provide insights into how the interaction of these systems shape our understanding of the world. PMID:26783734

  13. Geographic exposure modeling: a valuable extension of geographic information systems for use in environmental epidemiology.

    PubMed Central

    Beyea, J

    1999-01-01

    Geographic modeling of individual exposures using air pollution modeling techniques can help in both the design of environmental epidemiologic studies and in the assignment of measures that delineate regions that receive the highest exposure in space and time. Geographic modeling can help in the interpretation of environmental sampling data associated with airborne concentration or deposition, and can act as a sophisticated interpolator for such data, allowing values to be assigned to locations between points where the data have actually been collected. Recent advances allow for quantification of the uncertainty in a geographic model and the resulting impact on estimates of association, variability, and study power. In this paper we present the terminology and methodology of geographic modeling, describe applications to date in the field of epidemiology, and evaluate the potential of this relatively new tool. PMID:10229717

  14. Plastome data reveal multiple geographic origins of Quercus Group Ilex.

    PubMed

    Simeone, Marco Cosimo; Grimm, Guido W; Papini, Alessio; Vessella, Federico; Cardoni, Simone; Tordoni, Enrico; Piredda, Roberta; Franc, Alain; Denk, Thomas

    2016-01-01

    Nucleotide sequences from the plastome are currently the main source for assessing taxonomic and phylogenetic relationships in flowering plants and their historical biogeography at all hierarchical levels. One major exception is the large and economically important genus Quercus (oaks). Whereas differentiation patterns of the nuclear genome are in agreement with morphology and the fossil record, diversity patterns in the plastome are at odds with established taxonomic and phylogenetic relationships. However, the extent and evolutionary implications of this incongruence has yet to be fully uncovered. The DNA sequence divergence of four Euro-Mediterranean Group Ilex oak species (Quercus ilex L., Q. coccifera L., Q. aucheri Jaub. & Spach., Q. alnifolia Poech.) was explored at three chloroplast markers (rbcL, trnK/matK, trnH-psbA). Phylogenetic relationships were reconstructed including worldwide members of additional 55 species representing all Quercus subgeneric groups. Family and order sequence data were harvested from gene banks to better frame the observed divergence in larger taxonomic contexts. We found a strong geographic sorting in the focal group and the genus in general that is entirely decoupled from species boundaries. High plastid divergence in members of Quercus Group Ilex, including haplotypes shared with related, but long isolated oak lineages, point towards multiple geographic origins of this group of oaks. The results suggest that incomplete lineage sorting and repeated phases of asymmetrical introgression among ancestral lineages of Group Ilex and two other main Groups of Eurasian oaks (Cyclobalanopsis and Cerris) caused this complex pattern. Comparison with the current phylogenetic synthesis also suggests an initial high- versus mid-latitude biogeographic split within Quercus. High plastome plasticity of Group Ilex reflects geographic area disruptions, possibly linked with high tectonic activity of past and modern distribution ranges, that did not

  15. Geographical distribution of pelagic decapod shrimp in the Atlantic Ocean.

    PubMed

    Judkins, David C

    2014-12-16

    Ninety-one species of pelagic decapod shrimp were identified in 938 midwater-trawl collections taken between 1963 and 1974 from the North and South Atlantic. Distributional maps are provided for the most frequently occurring species. Nighttime abundance of most species was greatest within the upper 200 m. Degree of geographical overlap was estimated using the geometric mean of the proportion of joint occurrences with a value ≥ 0.5 deemed significant. Geographical distributions tended to be unique, and only 31 species had values ≥ 0.5 with one or more other species. Species within genera and within phylogenetic subgroups of Sergia were generally parapatric or partially overlapping in distribution. Five geographical groupings of co-occurring species across genera were identified: Subpolar-Temperate, Southern Hemisphere, Central, Tropical, Eastern Tropical and Western Tropical. The two species of the Southern Hemisphere group are circumpolar at temperate latitudes. The 12 species of the Central group occurred throughout the subtropical and tropical North and South Atlantic. The eight species of the Tropical group occurred broadly across the equatorial Atlantic and Caribbean with ranges usually extending into the Gulf of Mexico and northward in the Gulf Stream. The two species of the Western Tropical group occurred most often in the western tropics, but there were scattered occurrences at subtropical latitudes. The four species of the Eastern Tropical group were endemic to the Mauritanian Upwelling and the Angola-Benguela Frontal zones off western Africa. Two of the three species in the Subpolar-Temperate group had bipolar distributions, and all three occurred in the Mediterranean and in the Mauritanian Upwelling zone. Most Central, Tropical and Western Tropical species were present in the in the Gulf of Mexico. The 10 species from the Mediterranean were a mixture of Subpolar-Temperate, Central and benthopelagic species. Patterns of distribution in Atlantic pelagic

  16. Plastome data reveal multiple geographic origins of Quercus Group Ilex

    PubMed Central

    Grimm, Guido W.; Papini, Alessio; Vessella, Federico; Cardoni, Simone; Tordoni, Enrico; Piredda, Roberta; Franc, Alain; Denk, Thomas

    2016-01-01

    Nucleotide sequences from the plastome are currently the main source for assessing taxonomic and phylogenetic relationships in flowering plants and their historical biogeography at all hierarchical levels. One major exception is the large and economically important genus Quercus (oaks). Whereas differentiation patterns of the nuclear genome are in agreement with morphology and the fossil record, diversity patterns in the plastome are at odds with established taxonomic and phylogenetic relationships. However, the extent and evolutionary implications of this incongruence has yet to be fully uncovered. The DNA sequence divergence of four Euro-Mediterranean Group Ilex oak species (Quercus ilex L., Q. coccifera L., Q. aucheri Jaub. & Spach., Q. alnifolia Poech.) was explored at three chloroplast markers (rbcL, trnK/matK, trnH-psbA). Phylogenetic relationships were reconstructed including worldwide members of additional 55 species representing all Quercus subgeneric groups. Family and order sequence data were harvested from gene banks to better frame the observed divergence in larger taxonomic contexts. We found a strong geographic sorting in the focal group and the genus in general that is entirely decoupled from species boundaries. High plastid divergence in members of Quercus Group Ilex, including haplotypes shared with related, but long isolated oak lineages, point towards multiple geographic origins of this group of oaks. The results suggest that incomplete lineage sorting and repeated phases of asymmetrical introgression among ancestral lineages of Group Ilex and two other main Groups of Eurasian oaks (Cyclobalanopsis and Cerris) caused this complex pattern. Comparison with the current phylogenetic synthesis also suggests an initial high- versus mid-latitude biogeographic split within Quercus. High plastome plasticity of Group Ilex reflects geographic area disruptions, possibly linked with high tectonic activity of past and modern distribution ranges, that did not

  17. Quantitative Social Dialectology: Explaining Linguistic Variation Geographically and Socially

    PubMed Central

    Wieling, Martijn; Nerbonne, John; Baayen, R. Harald

    2011-01-01

    In this study we examine linguistic variation and its dependence on both social and geographic factors. We follow dialectometry in applying a quantitative methodology and focusing on dialect distances, and social dialectology in the choice of factors we examine in building a model to predict word pronunciation distances from the standard Dutch language to 424 Dutch dialects. We combine linear mixed-effects regression modeling with generalized additive modeling to predict the pronunciation distance of 559 words. Although geographical position is the dominant predictor, several other factors emerged as significant. The model predicts a greater distance from the standard for smaller communities, for communities with a higher average age, for nouns (as contrasted with verbs and adjectives), for more frequent words, and for words with relatively many vowels. The impact of the demographic variables, however, varied from word to word. For a majority of words, larger, richer and younger communities are moving towards the standard. For a smaller minority of words, larger, richer and younger communities emerge as driving a change away from the standard. Similarly, the strength of the effects of word frequency and word category varied geographically. The peripheral areas of the Netherlands showed a greater distance from the standard for nouns (as opposed to verbs and adjectives) as well as for high-frequency words, compared to the more central areas. Our findings indicate that changes in pronunciation have been spreading (in particular for low-frequency words) from the Hollandic center of economic power to the peripheral areas of the country, meeting resistance that is stronger wherever, for well-documented historical reasons, the political influence of Holland was reduced. Our results are also consistent with the theory of lexical diffusion, in that distances from the Hollandic norm vary systematically and predictably on a word by word basis. PMID:21912639

  18. An Assessment of the Use of Geographical Information Systems (GIS) in Teaching Geography in Singapore Schools

    ERIC Educational Resources Information Center

    Yap, Lee Yong; Tan, Geok Chin Ivy; Zhu, Xuan; Wettasinghe, Marissa C.

    2008-01-01

    In 1998, geographical information systems (GIS) were introduced to secondary schools in Singapore as a tool for teaching geography at the secondary and junior college levels. However, general observations and feedback from school teachers suggested that only a small number of secondary schools and junior colleges in Singapore were actually using…

  19. The Study of Geographic Differences in the Prevalence of Disability among Taiwanese Population

    ERIC Educational Resources Information Center

    Lin, Jin-Ding; Li, Chien-De; Lin, Lan-Ping; Hsu, Shang-Wei

    2012-01-01

    The present study analyzes data of the governmental reported general population and population of persons with disabilities from 2002 to 2009, to describe the disability prevalence and to test the overtime change with particular focused on the geographic differences in Taiwan. In average, the disability prevalence was 42.06% (range = 31.06%-80.04%…

  20. Investigating urban geochemistry using Geographical Information Systems.

    PubMed

    Thums, C; Farago, M

    2001-01-01

    Geographical Information System (GIS) is an interactive digital extension of the two-dimensional paper map. Customised maps are created by the selection and aggregation of data from independent sources to assist studies in urban geochemistry. The metropolitan area of Wolverhampton, in the West Midlands, UK is used to illustrate the types of output that can be generated. These include: geographic and geological feature; geochemical data and land use. Multi-layered maps can be used to investigate spatial relationships, for example, between elevated concentrations of metals in soils and industrial land use. Such maps can also be used to assist the assessment of potential exposure of groundwater, ecosystems and humans using maps incorporating guideline values for metals in soils. PMID:11732156

  1. ERBE Geographic Scene and Monthly Snow Data

    NASA Technical Reports Server (NTRS)

    Coleman, Lisa H.; Flug, Beth T.; Gupta, Shalini; Kizer, Edward A.; Robbins, John L.

    1997-01-01

    The Earth Radiation Budget Experiment (ERBE) is a multisatellite system designed to measure the Earth's radiation budget. The ERBE data processing system consists of several software packages or sub-systems, each designed to perform a particular task. The primary task of the Inversion Subsystem is to reduce satellite altitude radiances to fluxes at the top of the Earth's atmosphere. To accomplish this, angular distribution models (ADM's) are required. These ADM's are a function of viewing and solar geometry and of the scene type as determined by the ERBE scene identification algorithm which is a part of the Inversion Subsystem. The Inversion Subsystem utilizes 12 scene types which are determined by the ERBE scene identification algorithm. The scene type is found by combining the most probable cloud cover, which is determined statistically by the scene identification algorithm, with the underlying geographic scene type. This Contractor Report describes how the geographic scene type is determined on a monthly basis.

  2. Geographic Information Systems and travel health.

    PubMed

    Bauer, Irmgard L; Puotinen, Marji

    2002-01-01

    Questions dealing with space and/or location have always been integral to understanding and addressing health issues, such as charting the spread of a disease. Health researchers have traditionally used paper maps to explore the spatial dimensions of health. However, due to advances in technology, it is now possible to ask such questions using a suite of computer-based methods and tools that are collectively known as a Geographic Information System (GIS).

  3. Geographic Analysis of the Radiation Oncology Workforce

    SciTech Connect

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

    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.

  4. U-PLANT GEOGRAPHIC ZONE CLEANUP PROTOTYPE

    SciTech Connect

    ROMINE, L.D.

    2006-02-01

    The U Plant geographic zone (UPZ) occupies 0.83 square kilometers on the Hanford Site Central Plateau (200 Area). It encompasses the U Plant canyon (221-U Facility), ancillary facilities that supported the canyon, soil waste sites, and underground pipelines. The UPZ cleanup initiative coordinates the cleanup of the major facilities, ancillary facilities, waste sites, and contaminated pipelines (collectively identified as ''cleanup items'') within the geographic zone. The UPZ was selected as a geographic cleanup zone prototype for resolving regulatory, technical, and stakeholder issues and demonstrating cleanup methods for several reasons: most of the area is inactive, sufficient characterization information is available to support decisions, cleanup of the high-risk waste sites will help protect the groundwater, and the zone contains a representative cross-section of the types of cleanup actions that will be required in other geographic zones. The UPZ cleanup demonstrates the first of 22 integrated zone cleanup actions on the Hanford Site Central Plateau to address threats to groundwater, the environment, and human health. The UPZ contains more than 100 individual cleanup items. Cleanup actions in the zone will be undertaken using multiple regulatory processes and decision documents. Cleanup actions will include building demolition, waste site and pipeline excavation, and the construction of multiple, large engineered barriers. In some cases, different cleanup actions may be taken at item locations that are immediately adjacent to each other. The cleanup planning and field activities for each cleanup item must be undertaken in a coordinated and cohesive manner to ensure effective execution of the UPZ cleanup initiative. The UPZ zone cleanup implementation plan (ZCIP) was developed to address the need for a fundamental integration tool for UPZ cleanup. As UPZ cleanup planning and implementation moves forward, the ZCIP is intended to be a living document that will

  5. U Plant Geographic Zone Cleanup Prototype

    SciTech Connect

    Romine, L.D.; Leary, K.D.; Lackey, M.B.; Robertson, J.R.

    2006-07-01

    The U Plant geographic zone (UPZ) occupies 0.83 square kilometers on the Hanford Site Central Plateau (200 Area). It encompasses the U Plant canyon (221-U Facility), ancillary facilities that supported the canyon, soil waste sites, and underground pipelines. The UPZ cleanup initiative coordinates the cleanup of the major facilities, ancillary facilities, waste sites, and contaminated pipelines (collectively identified as 'cleanup items') within the geographic zone. The UPZ was selected as a geographic cleanup zone prototype for resolving regulatory, technical, and stakeholder issues and demonstrating cleanup methods for several reasons: most of the area is inactive, sufficient characterization information is available to support decisions, cleanup of the high-risk waste sites will help protect the groundwater, and the zone contains a representative cross-section of the types of cleanup actions that will be required in other geographic zones. The UPZ cleanup demonstrates the first of 22 integrated zone cleanup actions on the Hanford Site Central Plateau to address threats to groundwater, the environment, and human health. The UPZ contains more than 100 individual cleanup items. Cleanup actions in the zone will be undertaken using multiple regulatory processes and decision documents. Cleanup actions will include building demolition, waste site and pipeline excavation, and the construction of multiple, large engineered barriers. In some cases, different cleanup actions may be taken at item locations that are immediately adjacent to each other. The cleanup planning and field activities for each cleanup item must be undertaken in a coordinated and cohesive manner to ensure effective execution of the UPZ cleanup initiative. The UPZ zone cleanup implementation plan (ZCIP) [1] was developed to address the need for a fundamental integration tool for UPZ cleanup. As UPZ cleanup planning and implementation moves forward, the ZCIP is intended to be a living document that will

  6. Advanced Data Structure and Geographic Information Systems

    NASA Technical Reports Server (NTRS)

    Peuquet, D. (Principal Investigator)

    1984-01-01

    The current state of the art in specified areas of Geographic Information Systems GIS technology is examined. Study of the question of very large, efficient, heterogeneous spatial databases is required in order to explore the potential application of remotely sensed data for studying the long term habitability of the Earth. Research includes a review of spatial data structures and storage, development of operations required by GIS, and preparation of a testbed system to compare Vaster data structure with NASA's Topological Raster Structure.

  7. A Geographical Heuristic Routing Protocol for VANETs.

    PubMed

    Urquiza-Aguiar, Luis; Tripp-Barba, Carolina; Aguilar Igartua, Mónica

    2016-01-01

    Vehicular ad hoc networks (VANETs) leverage the communication system of Intelligent Transportation Systems (ITS). Recently, Delay-Tolerant Network (DTN) routing protocols have increased their popularity among the research community for being used in non-safety VANET applications and services like traffic reporting. Vehicular DTN protocols use geographical and local information to make forwarding decisions. However, current proposals only consider the selection of the best candidate based on a local-search. In this paper, we propose a generic Geographical Heuristic Routing (GHR) protocol that can be applied to any DTN geographical routing protocol that makes forwarding decisions hop by hop. GHR includes in its operation adaptations simulated annealing and Tabu-search meta-heuristics, which have largely been used to improve local-search results in discrete optimization. We include a complete performance evaluation of GHR in a multi-hop VANET simulation scenario for a reporting service. Our study analyzes all of the meaningful configurations of GHR and offers a statistical analysis of our findings by means of MANOVA tests. Our results indicate that the use of a Tabu list contributes to improving the packet delivery ratio by around 5% to 10%. Moreover, if Tabu is used, then the simulated annealing routing strategy gets a better performance than the selection of the best node used with carry and forwarding (default operation). PMID:27669254

  8. HIV care for geographically mobile populations.

    PubMed

    Taylor, Barbara S; Garduño, L Sergio; Reyes, Emily V; Valiño, Raziel; Rojas, Rita; Donastorg, Yeycy; Brudney, Karen; Hirsch, Jennifer

    2011-01-01

    The interaction between geographic mobility and risk for human immunodeficiency virus infection is well recognized, but what happens to those same individuals, once infected, as they transition to living with the infection? Does mobility affect their transition into medical care? If so, do mobile and nonmobile populations achieve similar success with antiretroviral treatment? The definition of mobility has changed over the centuries to encompass a complex phenotype including permanent migration, frequent travel, circular migration, and travel to and from treatment centers. The heterogeneity of these definitions leads to discordant findings. Investigations show that mobility has an impact on infection risk, but fewer data exist on the impact of geographic mobility on medical care and treatment outcomes. This review will examine existing data regarding the impact of geographic mobility on access to and maintenance in medical care and on adherence to antiretroviral therapy for those living with human immunodeficiency virus infection. It will also expand the concept of mobility to include data on the impact of the distance from residence to clinic on medical care and treatment adherence. Our conclusions are that the existing literature is limited by varying definitions of mobility and the inherent oversimplification necessary to apply a "mobility measure" in a statistical analysis. The impact of mobility on antiretroviral treatment outcomes deserves further exploration to both define the phenomenon and target interventions to these at-risk populations. PMID:21598261

  9. Geographical mobility in Wiltshire, 1754-1914.

    PubMed

    Day, Cathy

    2012-01-01

    The aim of this paper is to determine the birthplaces, rather than residences, of spouses married in two parishes in England and to consider the effect of local topography, religion and occupation on pre-marital geographic mobility. A wide array of primary documentary sources was used to construct a database of over 22,000 individuals who lived in south-west Wiltshire in the eighteenth, nineteenth and twentieth centuries. Individuals were arranged in family groups and pedigrees traced for several generations. Data were included on birthplace, religious affiliation, occupation and many other variables. Geographical mobility calculated from birthplace was higher than estimates derived from residence prior to marriage. Brides had shorter marital distances than grooms. There were noticeable changes in the frequency of marital distance at 4 miles and 11 miles. Spouses born outside the parish of marriage were more likely to come from certain villages in ways which cannot be explained merely by distance and size. The Somerset-Wiltshire border formed a barrier, although a porous one, to the flow of marriage partners. Occupation influenced geographical mobility: grooms from higher-status occupational groups were more likely to be born further away than grooms from lower-status occupational groups. Catholic grooms were more likely to be born in the parish of marriage than Protestant grooms, but were also more likely to be born more than 11 miles away.

  10. A Geographical Heuristic Routing Protocol for VANETs.

    PubMed

    Urquiza-Aguiar, Luis; Tripp-Barba, Carolina; Aguilar Igartua, Mónica

    2016-09-23

    Vehicular ad hoc networks (VANETs) leverage the communication system of Intelligent Transportation Systems (ITS). Recently, Delay-Tolerant Network (DTN) routing protocols have increased their popularity among the research community for being used in non-safety VANET applications and services like traffic reporting. Vehicular DTN protocols use geographical and local information to make forwarding decisions. However, current proposals only consider the selection of the best candidate based on a local-search. In this paper, we propose a generic Geographical Heuristic Routing (GHR) protocol that can be applied to any DTN geographical routing protocol that makes forwarding decisions hop by hop. GHR includes in its operation adaptations simulated annealing and Tabu-search meta-heuristics, which have largely been used to improve local-search results in discrete optimization. We include a complete performance evaluation of GHR in a multi-hop VANET simulation scenario for a reporting service. Our study analyzes all of the meaningful configurations of GHR and offers a statistical analysis of our findings by means of MANOVA tests. Our results indicate that the use of a Tabu list contributes to improving the packet delivery ratio by around 5% to 10%. Moreover, if Tabu is used, then the simulated annealing routing strategy gets a better performance than the selection of the best node used with carry and forwarding (default operation).

  11. Geographical assemblages of European raptors and owls

    NASA Astrophysics Data System (ADS)

    López-López, Pascual; Benavent-Corai, José; García-Ripollés, Clara

    2008-09-01

    In this work we look for geographical structure patterns in European raptors (Order: Falconiformes) and owls (Order: Strigiformes). For this purpose we have conducted our research using freely available tools such as statistical software and databases. To perform the study, presence-absence data for the European raptors and owl species (Class Aves) were downloaded from the BirdLife International website. Using the freely available "pvclust" R-package, we applied similarity Jaccard index and cluster analysis in order to delineate biogeographical relationships for European countries. According to the cluster of similarity, we found that Europe is structured into two main geographical assemblages. The larger length branch separated two main groups: one containing Iceland, Greenland and the countries of central, northern and northwestern Europe, and the other group including the countries of eastern, southern and southwestern Europe. Both groups are divided into two main subgroups. According to our results, the European raptors and owls could be considered structured into four meta-communities well delimited by suture zones defined by Remington (1968) [Remington, C.L., 1968. Suture-zones of hybrid interaction between recently joined biotas. Evol. Biol. 2, 321-428]. Climatic oscillations during the Quaternary Ice Ages could explain at least in part the modern geographical distribution of the group.

  12. [Geographic changes in exposure to dengue].

    PubMed

    Ménard, Béatrice

    2003-01-01

    Many factors are jointly involved in the changes in the epidemiological and clinical expressions of dengue fever, an arbovirus transmitted by Aedes mosquitoes. In the past forty years, this disease has spread throughout the tropical region, well beyond its original home in Southeast Asia. In some geographic areas, it now appears in a severe haemorrhagic form that requires specialized medical treatment. Many of its mechanisms and features depend on the etiologic agent, human host, and vectors as well as upon bioecologic and socioeconomic factors. Its epidemiological cycles are accordingly quite complex. The threat associated with three current transformations--its geographic extension, epidemiological changes, and aggravation of clinical symptoms--requires an approach that integrates geography and pathology. Such an analysis should provide tools to answer some of the riddles (i.e. specify the epidemiogenic geosystem) by sketching various combinations of factors that reflect the emergence of the disease in specific areas and play a role in its spread from one epidemic area to another. This synthesis about the diverse mutations of the disease calls for a methodical comparison by geographic characteristics and population groups.

  13. Geographically isolated wetlands: Rethinking a misnomer

    USGS Publications Warehouse

    Mushet, David M.; Calhoun, Aram J. K.; Alexander, Laurie C.; Cohen, Matthew J.; DeKeyser, Edward S.; Fowler, Laurie G.; Lane, Charles R.; Lang, Megan W.; Rains, Mark C.; Walls, Susan

    2015-01-01

    We explore the category “geographically isolated wetlands” (GIWs; i.e., wetlands completely surrounded by uplands at the local scale) as used in the wetland sciences. As currently used, the GIW category (1) hampers scientific efforts by obscuring important hydrological and ecological differences among multiple wetland functional types, (2) aggregates wetlands in a manner not reflective of regulatory and management information needs, (3) implies wetlands so described are in some way “isolated,” an often incorrect implication, (4) is inconsistent with more broadly used and accepted concepts of “geographic isolation,” and (5) has injected unnecessary confusion into scientific investigations and discussions. Instead, we suggest other wetland classification systems offer more informative alternatives. For example, hydrogeomorphic (HGM) classes based on well-established scientific definitions account for wetland functional diversity thereby facilitating explorations into questions of connectivity without an a priori designation of “isolation.” Additionally, an HGM-type approach could be used in combination with terms reflective of current regulatory or policymaking needs. For those rare cases in which the condition of being surrounded by uplands is the relevant distinguishing characteristic, use of terminology that does not unnecessarily imply isolation (e.g., “upland embedded wetlands”) would help alleviate much confusion caused by the “geographically isolated wetlands” misnomer.

  14. An Introduction to Urban Geographic Information Systems

    NASA Astrophysics Data System (ADS)

    Huxhold, William E.

    1991-03-01

    A nuts-and-bolts introduction to geographic information systems (GIS), this book outlines the basic concepts and diverse uses of this technology in a local government environment. Emphasizing the value of integrating data from various sources, the book provides a set of tools for improving the way public services are delivered, resources are managed, and policy decisions are made. Rather than stressing the computer technology that is so rapidly changing in the GIS industry, this book concentrates on the concepts upon which this technology is based: information systems design, computer-aided mapping, topological data structures, geographic base files, and land records systems. It also provides the latest information on the U.S. Census Bureau's TIGER files and the Global Positioning Satellite System established by the U.S. Department of Defense. Special features include fourteen case studies, a chapter describing the enormous effort required to set up and manage a typical GIS project, and an appendix on who is using GIS technology and how it is being used. Whether they run the GIS or help run the government, readers of An Introduction to Urban Geographic Information Systems will learn efficient and effective methods for improving the impact that local government has on its citizens.

  15. Geographic structure of European anchovy: A nuclear-DNA study

    NASA Astrophysics Data System (ADS)

    Bouchenak-Khelladi, Yanis; Durand, Jean-Dominique; Magoulas, Antonios; Borsa, Philippe

    2008-08-01

    Atlantic-Mediterranean anchovies were genetically characterized at two polymorphic nuclear loci (intron 6 of two creatine-kinase genes) and compared to reference Engraulis albidus and E. encrasicolus samples from the northern Western Mediterranean to provide new insights into their geographic structure. Northeastern Atlantic anchovy, represented by one sample from the Canary archipelago and one sample from the Alboran Sea, were genetically distinct from Mediterranean E. encrasicolus (Weir and Cockerham's ^θ = 0.027-0.311), indicating geographic isolation from either side of the Almería-Oran oceanographic front. Generally smaller genetic differences were evident among anchovy populations from different sub-basins in the Mediterranean ( ^θ = - 0.019-0.116), the genetic differences between Black Sea and Ionian Sea/Aegean Sea anchovies being the strongest ( ^θ = 0.002-0.116). There was no evidence of the presence of E. albidus in our samples outside Camargue (northern shore of the Western Mediterranean). However, a sample from the southern Western Mediterranean appeared to be genetically intermediate between E. albidus and Mediterranean E. encrasicolus, indicating possible hybridization. Anchovy from the Benguela current system off southern Africa possessed allele frequencies characteristic of E. albidus at one locus and Northeastern Atlantic anchovy at the other locus, suggesting past introgression.

  16. KBGIS-2: A knowledge-based geographic information system

    NASA Technical Reports Server (NTRS)

    Smith, T.; Peuquet, D.; Menon, S.; Agarwal, P.

    1986-01-01

    The architecture and working of a recently implemented knowledge-based geographic information system (KBGIS-2) that was designed to satisfy several general criteria for the geographic information system are described. The system has four major functions that include query-answering, learning, and editing. The main query finds constrained locations for spatial objects that are describable in a predicate-calculus based spatial objects language. The main search procedures include a family of constraint-satisfaction procedures that use a spatial object knowledge base to search efficiently for complex spatial objects in large, multilayered spatial data bases. These data bases are represented in quadtree form. The search strategy is designed to reduce the computational cost of search in the average case. The learning capabilities of the system include the addition of new locations of complex spatial objects to the knowledge base as queries are answered, and the ability to learn inductively definitions of new spatial objects from examples. The new definitions are added to the knowledge base by the system. The system is currently performing all its designated tasks successfully, although currently implemented on inadequate hardware. Future reports will detail the performance characteristics of the system, and various new extensions are planned in order to enhance the power of KBGIS-2.

  17. The use of geographical information system in health sector.

    PubMed

    Mechili, Aggelos; Zimeras, Stelios; Al-Fantel, Konstantina; Diomidous, Marianna

    2014-01-01

    The provision of health care has undergone radical changes during the last years. Geography plays an important role in understanding the dynamics of health, as well as the reasons why a disease is spreading. In general, a Geographic Information System (GIS) is based on the same principals with a traditional relational database. The main idea behind this study is the methodological approach as far as the implementation of a real- time electronic healthcare record is concerned, for the descriptive statistical analysis that uses geographical information to identify spatial data related to accidents. The purpose of developing such a health care record is to record the patients who were injured in accidents. The database that will be used for the development of the EHR is based on Microsoft Office 2007, which is considered to be one of the best tools for developing databases. The main table of the database includes the fields with demographics, ie name, surname, age, sex, address and place of birth. The primary key of the table Demographics is Patient_ID. The demographics from the table are connected to the table Admission with a relationship type one- to- many. The combination of these features in a graphic representation can be used to display the health problems on the map, so that the proper health policies can be applied. The results of the monitoring could be used as pilot instructions for spatial epidemiological analysis.

  18. Geographical distributions of lake trout strains stocked in Lake Ontario

    USGS Publications Warehouse

    Elrod, Joseph H.; O'Gorman, Robert; Schneider, Clifford P.; Schaner, Ted

    1996-01-01

    Geographical distributions of lake trout (Salvelinus namaycush) stocked at seven locations in U.S. waters and at four locations in Canadian waters of Lake Ontario were determined from fish caught with gill nets in September in 17 areas of U.S. waters and at 10 fixed locations in Canadian waters in 1986-95. For fish of a given strain stocked at a given location, geographical distributions were not different for immature males and immature females or for mature males and mature females. The proportion of total catch at the three locations nearest the stocking location was higher for mature fish than for immature fish in all 24 available comparisons (sexes combined) and was greater for fish stocked as yearlings than for those stocked as fingerlings in all eight comparisons. Mature fish were relatively widely dispersed from stocking locations indicating that their tendency to return to stocking locations for spawning was weak, and there was no appreciable difference in this tendency among strains. Mature lake trout were uniformly distributed among sampling locations, and the strain composition at stocking locations generally reflected the stocking history 5 to 6 years earlier. Few lake trout moved across Lake Ontario between the north and south shores or between the eastern outlet basin and the main lake basin. Limited dispersal from stocking sites supports the concept of stocking different genetic strains in various parts of the lake with the attributes of each strain selected to match environmental conditions in the portion of the lake where it is stocked.

  19. The use of geographical information system in health sector.

    PubMed

    Mechili, Aggelos; Zimeras, Stelios; Al-Fantel, Konstantina; Diomidous, Marianna

    2014-01-01

    The provision of health care has undergone radical changes during the last years. Geography plays an important role in understanding the dynamics of health, as well as the reasons why a disease is spreading. In general, a Geographic Information System (GIS) is based on the same principals with a traditional relational database. The main idea behind this study is the methodological approach as far as the implementation of a real- time electronic healthcare record is concerned, for the descriptive statistical analysis that uses geographical information to identify spatial data related to accidents. The purpose of developing such a health care record is to record the patients who were injured in accidents. The database that will be used for the development of the EHR is based on Microsoft Office 2007, which is considered to be one of the best tools for developing databases. The main table of the database includes the fields with demographics, ie name, surname, age, sex, address and place of birth. The primary key of the table Demographics is Patient_ID. The demographics from the table are connected to the table Admission with a relationship type one- to- many. The combination of these features in a graphic representation can be used to display the health problems on the map, so that the proper health policies can be applied. The results of the monitoring could be used as pilot instructions for spatial epidemiological analysis. PMID:25000047

  20. Geographic deaggregation of seismic hazard in the United States

    USGS Publications Warehouse

    Harmsen, S.; Frankel, A.

    2001-01-01

    The seismic hazard calculations for the 1996 national seismic hazard maps have been geographically deaggregated to assist in the understanding of the relative contributions of sources. These deaggregations are exhibited as maps with vertical bars whose heights are proportional to the contribution that each geographical cell makes to the ground-motion exceedance hazard. Bar colors correspond to average source magnitudes. We also extend the deaggregation analysis reported in Harmsen et al. (1999) to the western conterminous United States. In contrast to the central and eastern United States (CEUS); the influence of specific faults or characteristic events can be clearly identified. Geographic deaggregation for 0.2-sec and 1.0-sec pseudo spectral acceleration (SA) is performed for 10% probability of exceedance (PE) in 50 yr (475-yr mean return period) and 2% PE in 50 yr (2475-yr mean return period) for four western U.S. cities, Los Angeles, Salt Lake City, San Francisco, and Seattle, and for three central and eastern U.S. cities, Atlanta, Boston, and Saint Louis. In general, as the PE is lowered, the sources of hazard closer to the site dominate. Larger, more distant earthquakes contribute more significantly to hazard for 1.0-sec SA than for 0.2-sec SA. Additional maps of geographically deaggregated seismic hazard are available on the Internet for 120 cities in the conterminous United States (http://geohazards. cr.usgs.gov/eq/) for 1-sec SA and for 0.2-sec SA with a 2% PE in 50 yr. Examination of these maps of hazard contributions enables the investigator to determine the distance and azimuth to predominant sources, and their magnitudes. This information can be used to generate scenario earthquakes and corresponding time histories for seismic design and retrofit. Where fault density is lower than deaggregation cell dimensions, we can identify specific faults that contribute significantly to the seismic hazard at a given site. Detailed fault information enables

  1. Design Research of TIANDITU (Map Worl)-Based Geographic Information System for Travelling Service

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Zhang, H.; Wang, C.

    2014-04-01

    TIANDITU (Map World) is the public version of the National Platform for Common Geospatial Information Service, and the travelling channel is TIANDITU-based geographic information platform for travelling service. With the development of tourism, traditional ways for providing travelling information cannot meet the needs of travelers. As such, the travelling channel of TIANDITU focuses on providing travel information abundantly and precisely, which integrated the geographic information data of TIANDITU Version 2.0 and the authoritative information resources from China National Tourism Administration. Furthermore, spatial positioning, category and information query of various travelling information were offered for the public in the travelling channel. This research mainly involves three important parts: the system design, key technologies of the system design and application examples. Firstly, this paper introduced the design of TIANDITU-based geographic information system for travelling service, and the general and database design were described in detail. The designs for general, database and travelling service above should consider lots of factors which illustrated in the paper in order to guarantee the efficient service. The process of system construction, the content of geographic information for travelling and system functions of geographic information for travelling are also proposed via diagram in this part. Then several key technologies were discussed, including the travelling information integration for main node and among nodes, general architecture design and management system for travelling channel, web portals and system interface. From the perspective of main technologies, this part describes how TIANDITU travelling channel can realize various functions and reach the requirements from different users. Finally, three application examples about travelling information query were listed shortly. The functions and search results are shown clearly in this

  2. Global Seismicity: Three New Maps Compiled with Geographic Information Systems

    NASA Technical Reports Server (NTRS)

    Lowman, Paul D., Jr.; Montgomery, Brian C.

    1996-01-01

    This paper presents three new maps of global seismicity compiled from NOAA digital data, covering the interval 1963-1998, with three different magnitude ranges (mb): greater than 3.5, less than 3.5, and all detectable magnitudes. A commercially available geographic information system (GIS) was used as the database manager. Epicenter locations were acquired from a CD-ROM supplied by the National Geophysical Data Center. A methodology is presented that can be followed by general users. The implications of the maps are discussed, including the limitations of conventional plate models, and the different tectonic behavior of continental vs. oceanic lithosphere. Several little-known areas of intraplate or passive margin seismicity are also discussed, possibly expressing horizontal compression generated by ridge push.

  3. On the mixing time of geographical threshold graphs

    SciTech Connect

    Bradonjic, Milan

    2009-01-01

    In this paper, we study the mixing time of random graphs generated by the geographical threshold graph (GTG) model, a generalization of random geometric graphs (RGG). In a GTG, nodes are distributed in a Euclidean space, and edges are assigned according to a threshold function involving the distance between nodes as well as randomly chosen node weights. The motivation for analyzing this model is that many real networks (e.g., wireless networks, the Internet, etc.) need to be studied by using a 'richer' stochastic model (which in this case includes both a distance between nodes and weights on the nodes). We specifically study the mixing times of random walks on 2-dimensional GTGs near the connectivity threshold. We provide a set of criteria on the distribution of vertex weights that guarantees that the mixing time is {Theta}(n log n).

  4. Geographic mobility of scientists: sex differences and family constraints.

    PubMed

    Shauman, K A; Xie, Y

    1996-11-01

    Women scientists are much more likely than men scientists to be in two-career marriages. This study examines the argument that the higher prevalence of two-career marriages among women scientists presents a significant impediment to their geographic mobility. Three hypotheses are developed and tested. First, scientists in two-career families are less likely to migrate than scientists in one-career families. Second, the effect of two-career marriages on the probability of migration differs with gender; women are affected more negatively. Third, the effect of children on the probability of migration differs with gender; women are affected more negatively. The empirical work uses a data set of doctoral scientists extracted from the 5% Public Use Microdata Sample from the 1990 census. The first two hypotheses are not confirmed by the empirical results, but we find evidence supporting the third. Family constraints on women scientists' careers generally appear to be weak, but become acute when they have children.

  5. 33 CFR 169.10 - What geographic coordinates are used?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false What geographic coordinates are... coordinates are used? Geographic coordinates expressed in terms of latitude or longitude, or both, are not... of 1983 (NAD 83), unless such geographic coordinates are expressly labeled NAD 83....

  6. Geographic Information Systems: A Kaleidoscope. Resources in Technology.

    ERIC Educational Resources Information Center

    Deal, Walter F.

    1998-01-01

    Geographic Information Systems (GIS) are a combination of maps and databases that provides geographical information not otherwise possible. The result of combining street data and geographic data is a precision map showing exact street locations. GIS can be used by delivery people, emergency vehicles, and taxicabs. (JOW)

  7. Effect of Geographic Distance on Distance Education: An Empirical Study

    ERIC Educational Resources Information Center

    Luo, Heng; Robinson, Anthony C.; Detwiler, Jim

    2014-01-01

    This study investigates the effect of geographic distance on students' distance learning experience with the aim to provide tentative answers to a fundamental question--does geographic distance matter in distance education? Using educational outcome data collected from an online master's program in Geographic Information Systems, this…

  8. Geographic Accessibility to Higher Education on the Island of Ireland

    ERIC Educational Resources Information Center

    Walsh, Sharon; Flannery, Darragh; Cullinan, John

    2015-01-01

    This paper presents, for the first time, comprehensive measures of geographic accessibility to higher education both within and between the Republic of Ireland and Northern Ireland. Using geographic information system techniques, we find high levels of geographic accessibility to higher education in both jurisdictions. However, when we…

  9. Introduction to the Complex Geospatial Web in Geographical Education

    ERIC Educational Resources Information Center

    Papadimitriou, Fivos

    2010-01-01

    The Geospatial Web is emerging in the geographical education landscape in all its complexity. How will geographers and educators react? What are the most important facets of this development? After reviewing the possible impacts on geographical education, it can be conjectured that the Geospatial Web will eventually replace the usual geographical…

  10. 47 CFR 95.823 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. Parties seeking Commission approval of geographic partitioning or spectrum disaggregation of 218-219 MHz Service system licenses shall request...

  11. 47 CFR 95.823 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. Parties seeking Commission approval of geographic partitioning or spectrum disaggregation of 218-219 MHz Service system licenses shall request...

  12. 47 CFR 95.823 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. Parties seeking Commission approval of geographic partitioning or spectrum disaggregation of 218-219 MHz Service system licenses shall request...

  13. 47 CFR 95.823 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. Parties seeking Commission approval of geographic partitioning or spectrum disaggregation of 218-219 MHz Service system licenses shall request...

  14. 47 CFR 95.823 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. Parties seeking Commission approval of geographic partitioning or spectrum disaggregation of 218-219 MHz Service system licenses shall request...

  15. 47 CFR 22.503 - Paging geographic area authorizations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Paging geographic area authorizations. 22.503... PUBLIC MOBILE SERVICES Paging and Radiotelephone Service § 22.503 Paging geographic area authorizations. The FCC considers applications for and issues paging geographic area authorizations in the Paging...

  16. 47 CFR 22.503 - Paging geographic area authorizations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Paging geographic area authorizations. 22.503... PUBLIC MOBILE SERVICES Paging and Radiotelephone Service § 22.503 Paging geographic area authorizations. The FCC considers applications for and issues paging geographic area authorizations in the Paging...

  17. 47 CFR 22.503 - Paging geographic area authorizations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Paging geographic area authorizations. 22.503... PUBLIC MOBILE SERVICES Paging and Radiotelephone Service § 22.503 Paging geographic area authorizations. The FCC considers applications for and issues paging geographic area authorizations in the Paging...

  18. Geographical Inquiry in Australian Schools: A Retrospective Analysis

    ERIC Educational Resources Information Center

    Kidman, Gillian

    2012-01-01

    This paper explores the occurrence of geographical inquiry in the Australian curriculum since Geography became a high school subject in 1911. In this historical overview, I reflect upon my own experiences of undertaking geographical inquiry during the 1970s and 1980s. Primary school geographical inquiry experiences can be virtually non-existent…

  19. Geographic Information Processings for Astronomical Site Survey

    NASA Astrophysics Data System (ADS)

    Wu, N.; Liu, Y.; Zhao, M. Y.

    2015-01-01

    The geographic information is of great importance for the site survey of ground-based telescopes. Especially, an effective utilization of the geographic information system (GIS) has been one of the most significant methods for the remote analysis of modern site survey. The astronomical site survey should give consideration to the following geographical conditions: a large relative fall, convenient traffic conditions, and far away from populated areas. Taking into account of the convenience of construction and maintenance of the observatories as well as the living conditions of the scientists-in-residence, the optimum candidate locations may meet the conditions to be at a altitude between 3000 m and 5000 m and within one-hour drive from villages/towns. In this paper, as an example, we take the regions of the Great Baicao mountain ridge at Dayao county in Yunnan province to research the role of the GIS for site survey task. The results indicate that the GIS can provide accurate and intuitive data for us to understand the three dimensional landforms, rivers, roads, villages, and the distributions of the electric power as well as to forecast the tendency of the population and city development around. According to the analysis based on the GIS, we find that the top of the Great Baicao mountain ridge is flat and droughty. There are few inhabitants to distribute around the place while the traffic conditions are convenient. Moreover, it is a natural conservation area protected by the local government, and no industry with pollution sources exists in this region. Its top is 1500 m higher than the nearby village 10 km away, and 1800 m higher than the town center 50 km away. The Great Baicao mountain ridge is definitely an isolated peak in the area of the Yi nationality of Yunnan. Therefore, the GIS data analysis is a very useful for the remote investigation stage for site survey, and the GIS is the indispensable source for modern astronomical site survey.

  20. Geographic Information Systems and Web Page Development

    NASA Technical Reports Server (NTRS)

    Reynolds, Justin

    2004-01-01

    The Facilities Engineering and Architectural Branch is responsible for the design and maintenance of buildings, laboratories, and civil structures. In order to improve efficiency and quality, the FEAB has dedicated itself to establishing a data infrastructure based on Geographic Information Systems, GIS. The value of GIS was explained in an article dating back to 1980 entitled "Need for a Multipurpose Cadastre" which stated, "There is a critical need for a better land-information system in the United States to improve land-conveyance procedures, furnish a basis for equitable taxation, and provide much-needed information for resource management and environmental planning." Scientists and engineers both point to GIS as the solution. What is GIS? According to most text books, Geographic Information Systems is a class of software that stores, manages, and analyzes mapable features on, above, or below the surface of the earth. GIS software is basically database management software to the management of spatial data and information. Simply put, Geographic Information Systems manage, analyze, chart, graph, and map spatial information. GIS can be broken down into two main categories, urban GIS and natural resource GIS. Further still, natural resource GIS can be broken down into six sub-categories, agriculture, forestry, wildlife, catchment management, archaeology, and geology/mining. Agriculture GIS has several applications, such as agricultural capability analysis, land conservation, market analysis, or whole farming planning. Forestry GIs can be used for timber assessment and management, harvest scheduling and planning, environmental impact assessment, and pest management. GIS when used in wildlife applications enables the user to assess and manage habitats, identify and track endangered and rare species, and monitor impact assessment.

  1. Workload management and geographic disorientation in aviation incidents: A review of the ASRS data base

    NASA Technical Reports Server (NTRS)

    Williams, Henry P.; Tham, Mingpo; Wickens, Christopher D.

    1993-01-01

    NASA's Aviation Safety Reporting System (ASRS) incident reports are reviewed in two related areas: pilots' failures to appropriately manage tasks, and breakdowns in geographic orientation. Examination of 51 relevant reports on task management breakdowns revealed that altitude busts and inappropriate runway usee were the most frequently reported consequences. Task management breakdowns appeared to occur at all levels of expertise, and prominent causal factors were related to breakdowns in crew communications, over-involvement with the flight management system and, for small (general aviation) aircraft, preoccupation with weather. Analysis of the 83 cases of geographic disorientation suggested that these too occurred at all levels of pilot experience. With regard to causal factors, a majority was related to poor cockpit resource management, in which inattention led to a loss of geographic awareness. Other leading causes were related to poor weather and poor decision making. The potential of the ASRS database for contributing to research and design issues is addressed.

  2. A geographical approach for integrating belief networks and Geographic Information Sciences to probabilistically predict river depth

    NASA Astrophysics Data System (ADS)

    Hopper, Nathan Lee

    Geography is, traditionally, a discipline dedicated to answering complex spatial questions. Although spatial statistical techniques, such as weighted regressions and weighted overlay analyses, are commonplace within geographical sciences, probabilistic reasoning, and uncertainty analyses are not typical. For example, belief networks are statistically robust and computationally powerful, but are not strongly integrated into geographic information systems. This is one of the reasons that belief networks have not been more widely utilized within the environmental sciences community. Geography's traditional method of delivering information through maps provides a mechanism for conveying probabilities and uncertainties to decision makers in a clear, concise manner. This study will couple probabilistic methods with Geographic Information Sciences (GISc), resulting in a practical decision system framework. While the methods for building the decision system in this study are focused on the identification of environmental navigation hazards, the decision system framework concept is not bound by this study and can be applied to other complex environmental questions.

  3. Geographical information systems and tropical medicine

    PubMed Central

    KHAN, O. A.; DAVENHALL, W.; ALI, M.; CASTILLO-SALGADO, C.; VAZQUEZ-PROKOPEC, G.; KITRON, U.; SOARES MAGALHÃES, R. J.; CLEMENTS, A. C. A.

    2013-01-01

    In terms of their applicability to the field of tropical medicine, geographical information systems (GIS) have developed enormously in the last two decades. This article reviews some of the pertinent and representative applications of GIS, including the use of such systems and remote sensing for the mapping of Chagas disease and human helminthiases, the use of GIS in vaccine trials, and the global applications of GIS for health-information management, disease epidemiology, and pandemic planning. The future use of GIS as a decision-making tool and some barriers to the widespread implementation of such systems in developing settings are also discussed. PMID:20659391

  4. Recent trends in geographic information system research

    NASA Technical Reports Server (NTRS)

    Clarke, K. C.

    1986-01-01

    This paper reviews recent contributions to the body of published research on Geographic Information Systems (GISs). Increased usages of GISs have placed a new demand upon the academic and research community and despite some lack of formalized definitions, categorizations, terminologies, and standard data structures, the community has risen to the challenge. Examinations of published GIS research, in particular on GIS data structures, reveal a healthy, active research community which is using a truly interdisciplinary approach. Future work will undoubtably lead to a clearer understanding of the problems of handling spatial data, while producing a new generation of highly sophisticated GISs.

  5. A multidimensional representation model of geographic features

    USGS Publications Warehouse

    Usery, E. Lynn; Timson, George; Coletti, Mark

    2016-01-28

    A multidimensional model of geographic features has been developed and implemented with data from The National Map of the U.S. Geological Survey. The model, programmed in C++ and implemented as a feature library, was tested with data from the National Hydrography Dataset demonstrating the capability to handle changes in feature attributes, such as increases in chlorine concentration in a stream, and feature geometry, such as the changing shoreline of barrier islands over time. Data can be entered directly, from a comma separated file, or features with attributes and relationships can be automatically populated in the model from data in the Spatial Data Transfer Standard format.

  6. Taxonomical and geographical occurrence of Libyans scorpions.

    PubMed

    Zourgui, L; Maammar, M; Emetris, R

    2008-01-01

    Nine different species of scorpions can be recognized from more than 5000 samples collected from different areas in Libya: Leiurus quinquestriatus, Androctonus bicolor, Androctonus australis, Androctonus amoreuxi, Buthacus leptochelys, Buthus occitanus, Buthacus arenicola, Orthochirus innesi and Scorpio maurus. The geographical occurrence showed that Leiurus quinquestriatus seems to be restricted to the Southern areas. On the contrary, Buthus occitanus was found in the costal regions. Other species such as Androctonus were widely spread in all regions. Buthacus Leptochelys, Orthochirus innesi and Scorpio maurus were found, in the East (Aujlah, Jalu), the South (Wadi-Atbah) and the Western cost of Libya respectively. PMID:19469419

  7. A multidimensional representation model of geographic features

    USGS Publications Warehouse

    Usery, E. Lynn; Timson, George; Coletti, Mark

    2016-01-01

    A multidimensional model of geographic features has been developed and implemented with data from The National Map of the U.S. Geological Survey. The model, programmed in C++ and implemented as a feature library, was tested with data from the National Hydrography Dataset demonstrating the capability to handle changes in feature attributes, such as increases in chlorine concentration in a stream, and feature geometry, such as the changing shoreline of barrier islands over time. Data can be entered directly, from a comma separated file, or features with attributes and relationships can be automatically populated in the model from data in the Spatial Data Transfer Standard format.

  8. 5 CFR 536.303 - Geographic conversion.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... pay retention rules in this subpart or any other simultaneous pay action (other than a general pay... simultaneous general pay adjustment under § 536.305) to derive the converted retained rate that will be used...

  9. Effects of geographical heterogeneity in species interactions on the evolution of venom genes.

    PubMed

    Chang, Dan; Olenzek, Amy M; Duda, Thomas F

    2015-04-22

    Geographical heterogeneity in the composition of biotic interactions can create a mosaic of selection regimes that may drive the differentiation of phenotypes that operate at the interface of these interactions. Nonetheless, little is known about effects of these geographical mosaics on the evolution of genes encoding traits associated with species interactions. Predatory marine snails of the family Conidae use venom, a cocktail of conotoxins, to capture prey. We characterized patterns of geographical variation at five conotoxin genes of a vermivorous species, Conus ebraeus, at Hawaii, Guam and American Samoa, and evaluated how these patterns of variation are associated with geographical heterogeneity in prey utilization. All populations show distinct patterns of prey utilization. Three 'highly polymorphic' conotoxin genes showed significant geographical differences in allelic frequency, and appear to be affected by different modes of selection among populations. Two genes exhibited low levels of diversity and a general lack of differentiation among populations. Levels of diversity of 'highly polymorphic' genes exhibit a positive relationship with dietary breadth. The different patterns of evolution exhibited by conotoxin genes suggest that these genes play different roles in prey capture, and that some genes are more greatly affected by differences in predator-prey interactions than others. Moreover, differences in dietary breadth appear to have a greater influence on the differentiation of venoms than differences in the species of prey. PMID:25788600

  10. Effects of geographical heterogeneity in species interactions on the evolution of venom genes.

    PubMed

    Chang, Dan; Olenzek, Amy M; Duda, Thomas F

    2015-04-22

    Geographical heterogeneity in the composition of biotic interactions can create a mosaic of selection regimes that may drive the differentiation of phenotypes that operate at the interface of these interactions. Nonetheless, little is known about effects of these geographical mosaics on the evolution of genes encoding traits associated with species interactions. Predatory marine snails of the family Conidae use venom, a cocktail of conotoxins, to capture prey. We characterized patterns of geographical variation at five conotoxin genes of a vermivorous species, Conus ebraeus, at Hawaii, Guam and American Samoa, and evaluated how these patterns of variation are associated with geographical heterogeneity in prey utilization. All populations show distinct patterns of prey utilization. Three 'highly polymorphic' conotoxin genes showed significant geographical differences in allelic frequency, and appear to be affected by different modes of selection among populations. Two genes exhibited low levels of diversity and a general lack of differentiation among populations. Levels of diversity of 'highly polymorphic' genes exhibit a positive relationship with dietary breadth. The different patterns of evolution exhibited by conotoxin genes suggest that these genes play different roles in prey capture, and that some genes are more greatly affected by differences in predator-prey interactions than others. Moreover, differences in dietary breadth appear to have a greater influence on the differentiation of venoms than differences in the species of prey.

  11. Geographic wormhole detection in wireless sensor networks.

    PubMed

    Sookhak, Mehdi; Akhundzada, Adnan; Sookhak, Alireza; Eslaminejad, Mohammadreza; Gani, Abdullah; Khurram Khan, Muhammad; Li, Xiong; Wang, Xiaomin

    2015-01-01

    Wireless sensor networks (WSNs) are ubiquitous and pervasive, and therefore; highly susceptible to a number of security attacks. Denial of Service (DoS) attack is considered the most dominant and a major threat to WSNs. Moreover, the wormhole attack represents one of the potential forms of the Denial of Service (DoS) attack. Besides, crafting the wormhole attack is comparatively simple; though, its detection is nontrivial. On the contrary, the extant wormhole defense methods need both specialized hardware and strong assumptions to defend against static and dynamic wormhole attack. The ensuing paper introduces a novel scheme to detect wormhole attacks in a geographic routing protocol (DWGRP). The main contribution of this paper is to detect malicious nodes and select the best and the most reliable neighbors based on pairwise key pre-distribution technique and the beacon packet. Moreover, this novel technique is not subject to any specific assumption, requirement, or specialized hardware, such as a precise synchronized clock. The proposed detection method is validated by comparisons with several related techniques in the literature, such as Received Signal Strength (RSS), Authentication of Nodes Scheme (ANS), Wormhole Detection uses Hound Packet (WHOP), and Wormhole Detection with Neighborhood Information (WDI) using the NS-2 simulator. The analysis of the simulations shows promising results with low False Detection Rate (FDR) in the geographic routing protocols. PMID:25602616

  12. Mapping hydrologic connectivity of geographically isolated wetlands

    NASA Astrophysics Data System (ADS)

    Ameli, Ali; Creed, Irena

    2016-04-01

    Geographically isolated wetlands (GIWs) are characterized as depressional landscape features completely surrounded by uplands. These small and typically circular landscape features represent a vast majority of wetlands in various landscapes in North America (98% of all wetlands in the Prairie Pothole Region). Geographical isolation, however, does not imply the hydrological isolation. Although geospatial data (e.g., aerial photos) suggested that GIWs lack a persistent surface water connection, the groundwater connection between GIWs and navigable downstream waters can be substantial with large fluxes at the regional scales. The surface/subsurface connections among GIWs and between GIWs and navigable waters are difficult to map and quantify. This is intimately tied to the fact that an efficient incorporation of these small geometric features and characterization of the mechanisms behind these connectivities are challenging within grid-based simulators. We used a physically-based grid-free groundwater-surface water interaction and surface flow routing schemes to map and assess the watershed-scale GIWs connectivity within an extensively studied watershed at the Canadian prairie pothole region with high density of GIWs. The results showed that there is a persistent subsurface connectivity among GIWs and between GIWs and navigable waters. Surface connection was rare and only occurred during extreme events. The results of this paper have significant implications for developing scientifically grounded environmental policy for protection of GIWs within North American Prairie.

  13. Global Health, Geographical Contingency, and Contingent Geographies

    PubMed Central

    Herrick, Clare

    2016-01-01

    Health geography has emerged from under the “shadow of the medical” to become one of the most vibrant of all the subdisciplines. Yet, this success has also meant that health research has become increasingly siloed within this subdisciplinary domain. As this article explores, this represents a potential lost opportunity with regard to the study of global health, which has instead come to be dominated by anthropology and political science. Chief among the former's concerns are exploring the gap between the programmatic intentions of global health and the unintended or unanticipated consequences of their deployment. This article asserts that recent work on contingency within geography offers significant conceptual potential for examining this gap. It therefore uses the example of alcohol taxation in Botswana, an emergent global health target and tool, to explore how geographical contingency and the emergent, contingent geographies that result might help counter the prevailing tendency for geography to be side-stepped within critical studies of global health. At the very least, then, this intervention aims to encourage reflection by geographers on how to make explicit the all-too-often implicit links between their research and global health debates located outside the discipline. PMID:27611662

  14. Geographic wormhole detection in wireless sensor networks.

    PubMed

    Sookhak, Mehdi; Akhundzada, Adnan; Sookhak, Alireza; Eslaminejad, Mohammadreza; Gani, Abdullah; Khurram Khan, Muhammad; Li, Xiong; Wang, Xiaomin

    2015-01-01

    Wireless sensor networks (WSNs) are ubiquitous and pervasive, and therefore; highly susceptible to a number of security attacks. Denial of Service (DoS) attack is considered the most dominant and a major threat to WSNs. Moreover, the wormhole attack represents one of the potential forms of the Denial of Service (DoS) attack. Besides, crafting the wormhole attack is comparatively simple; though, its detection is nontrivial. On the contrary, the extant wormhole defense methods need both specialized hardware and strong assumptions to defend against static and dynamic wormhole attack. The ensuing paper introduces a novel scheme to detect wormhole attacks in a geographic routing protocol (DWGRP). The main contribution of this paper is to detect malicious nodes and select the best and the most reliable neighbors based on pairwise key pre-distribution technique and the beacon packet. Moreover, this novel technique is not subject to any specific assumption, requirement, or specialized hardware, such as a precise synchronized clock. The proposed detection method is validated by comparisons with several related techniques in the literature, such as Received Signal Strength (RSS), Authentication of Nodes Scheme (ANS), Wormhole Detection uses Hound Packet (WHOP), and Wormhole Detection with Neighborhood Information (WDI) using the NS-2 simulator. The analysis of the simulations shows promising results with low False Detection Rate (FDR) in the geographic routing protocols.

  15. Geographic Wormhole Detection in Wireless Sensor Networks

    PubMed Central

    Sookhak, Mehdi; Akhundzada, Adnan; Sookhak, Alireza; Eslaminejad, Mohammadreza; Gani, Abdullah; Khurram Khan, Muhammad; Li, Xiong; Wang, Xiaomin

    2015-01-01

    Wireless sensor networks (WSNs) are ubiquitous and pervasive, and therefore; highly susceptible to a number of security attacks. Denial of Service (DoS) attack is considered the most dominant and a major threat to WSNs. Moreover, the wormhole attack represents one of the potential forms of the Denial of Service (DoS) attack. Besides, crafting the wormhole attack is comparatively simple; though, its detection is nontrivial. On the contrary, the extant wormhole defense methods need both specialized hardware and strong assumptions to defend against static and dynamic wormhole attack. The ensuing paper introduces a novel scheme to detect wormhole attacks in a geographic routing protocol (DWGRP). The main contribution of this paper is to detect malicious nodes and select the best and the most reliable neighbors based on pairwise key pre-distribution technique and the beacon packet. Moreover, this novel technique is not subject to any specific assumption, requirement, or specialized hardware, such as a precise synchronized clock. The proposed detection method is validated by comparisons with several related techniques in the literature, such as Received Signal Strength (RSS), Authentication of Nodes Scheme (ANS), Wormhole Detection uses Hound Packet (WHOP), and Wormhole Detection with Neighborhood Information (WDI) using the NS-2 simulator. The analysis of the simulations shows promising results with low False Detection Rate (FDR) in the geographic routing protocols. PMID:25602616

  16. Acquiring geographical data with web harvesting

    NASA Astrophysics Data System (ADS)

    Dramowicz, K.

    2016-04-01

    Many websites contain very attractive and up to date geographical information. This information can be extracted, stored, analyzed and mapped using web harvesting techniques. Poorly organized data from websites are transformed with web harvesting into a more structured format, which can be stored in a database and analyzed. Almost 25% of web traffic is related to web harvesting, mostly while using search engines. This paper presents how to harvest geographic information from web documents using the free tool called the Beautiful Soup, one of the most commonly used Python libraries for pulling data from HTML and XML files. It is a relatively easy task to process one static HTML table. The more challenging task is to extract and save information from tables located in multiple and poorly organized websites. Legal and ethical aspects of web harvesting are discussed as well. The paper demonstrates two case studies. The first one shows how to extract various types of information about the Good Country Index from the multiple web pages, load it into one attribute table and map the results. The second case study shows how script tools and GIS can be used to extract information from one hundred thirty six websites about Nova Scotia wines. In a little more than three minutes a database containing one hundred and six liquor stores selling these wines is created. Then the availability and spatial distribution of various types of wines (by grape types, by wineries, and by liquor stores) are mapped and analyzed.

  17. Global Health, Geographical Contingency, and Contingent Geographies

    PubMed Central

    Herrick, Clare

    2016-01-01

    Health geography has emerged from under the “shadow of the medical” to become one of the most vibrant of all the subdisciplines. Yet, this success has also meant that health research has become increasingly siloed within this subdisciplinary domain. As this article explores, this represents a potential lost opportunity with regard to the study of global health, which has instead come to be dominated by anthropology and political science. Chief among the former's concerns are exploring the gap between the programmatic intentions of global health and the unintended or unanticipated consequences of their deployment. This article asserts that recent work on contingency within geography offers significant conceptual potential for examining this gap. It therefore uses the example of alcohol taxation in Botswana, an emergent global health target and tool, to explore how geographical contingency and the emergent, contingent geographies that result might help counter the prevailing tendency for geography to be side-stepped within critical studies of global health. At the very least, then, this intervention aims to encourage reflection by geographers on how to make explicit the all-too-often implicit links between their research and global health debates located outside the discipline.

  18. Fundamental problems on scale of geographical information science

    NASA Astrophysics Data System (ADS)

    Liu, Kai; Wu, Hehai; Hu, Jie

    2007-06-01

    Traditionally, the description of the scale of geographical information is mainly concerned with spatiality and its temporal character and semantic character is ignored. With a few of new techniques and way such as 3D geographical information system, temporal geographical information system, virtual geographical environment, electronic map appears, the traditional description of scale of geographical information shows its deficiencies to make certain of every aspect of it. At first, in this paper we try to extend the connotation and the dimension of scale of geographical information to full the need of describing the every aspects of it, and give three-tiered conceptualization of its scale as: kinds of scale; dimensions of scale; components of scale. The dimension of scale of geographical information is consisted of spatial dimension, temporal dimension and semantic dimension. The classifications of scale of geographical information are of phenomena scale, measure scale and token scale. The components of scale of geographical information are of extension, granularity (resolution) and interval. It is through the Cartesian product of kinds of scale and components of scale can we define the particulars of every aspects of scale of geographical information. At last in this paper the transform of scale of geographical information and issue of scale choice is discussed.

  19. Remote sensing research in geographic education: An alternative view

    NASA Technical Reports Server (NTRS)

    Wilson, H.; Cary, T. K.; Goward, S. N.

    1981-01-01

    It is noted that within many geography departments remote sensing is viewed as a mere technique a student should learn in order to carry out true geographic research. This view inhibits both students and faculty from investigation of remotely sensed data as a new source of geographic knowledge that may alter our understanding of the Earth. The tendency is for geographers to accept these new data and analysis techniques from engineers and mathematicians without questioning the accompanying premises. This black-box approach hinders geographic applications of the new remotely sensed data and limits the geographer's contribution to further development of remote sensing observation systems. It is suggested that geographers contribute to the development of remote sensing through pursuit of basic research. This research can be encouraged, particularly among students, by demonstrating the links between geographic theory and remotely sensed observations, encouraging a healthy skepticism concerning the current understanding of these data.

  20. Integrating Geographic Information Systems (GIS) Applications into Business Courses Using Online Business Geographics Modules

    ERIC Educational Resources Information Center

    Miller, Fred; Mangold, W. Glynn; Holmes, Terry

    2006-01-01

    Although the value of geographic information systems (GIS) technologies is recognized by practitioners and educators alike, GIS instruction has yet to make significant inroads into business curricula. In this article, the authors discuss the constraints of integrating GIS tools into business education. They develop a prototype module for…

  1. Understanding of the relationship between vegetation change and physical geographic factors based on geographical detector

    NASA Astrophysics Data System (ADS)

    Pang, Jing; Du, Ziqiang; Zhang, Xiaoyu

    2015-12-01

    In order to analyze the effect of physical geographic factors on vegetation change in arid and semi-arid ecosystems, assess the relative role of individual physical geographic factors and the interaction between factors on vegetation changes quantitatively, this study takes the Xinjiang area as an example, uses the GIS spatial analysis technology and Geographical Detector model based on the analysis of variance to analysis the influence of physical geographic factors on the vegetation quantitatively. First of all, the spatial-temporal variations of vegetation in Xinjiang area over the last 30 years were analyzed using 1982-2011 GIMMS NDVI3g data as the indicator of vegetation activity. Secondly, the effects of mean annual precipitation, mean annual temperature, sunshine duration, mean annual wind velocity, DEM, slope and aspect, soil type and vegetation type were selected as potential physical geographic factors. Finally, the influence of physical geographic factors on vegetation change in Xinjiang area was analyzed using the Geographical Detector model. The results show that: (1) the annual coverage of vegetation in Xinjiang area was gradually increasing in 1982-2011 years (linear rate 0.0017/a, P=0.000). (2) the area of vegetation improvement was greater than the area of vegetation degradation. The area of vegetation improvement was mainly distributed in the northern part of the Tianshan Mountains and the Tarim Watershed, the vegetation degradation region was mainly distributed in the southern and Northeast part of Xinjiang. (3) precipitation, soil and vegetation types had the greatest influence on NDVI, followed by temperature, sunshine duration and DEM, and the other factors had little effect. (4) DEM enhanced the effect of soil type on NDVI, and sunshine duration and DEM enhanced all the effect of temperature on NDVI. So, sunshine duration and DEM can be used as the auxiliary indicator in the vegetation growth monitoring. Our results brought new insights on

  2. Estimating a geographically explicit model of population divergence.

    PubMed

    Knowles, L Lacey; Carstens, Bryan C

    2007-03-01

    Patterns of genetic variation can provide valuable insights for deciphering the relative roles of different evolutionary processes in species differentiation. However, population-genetic models for studying divergence in geographically structured species are generally lacking. Since these are the biogeographic settings where genetic drift is expected to predominate, not only are population-genetic tests of hypotheses in geographically structured species constrained, but generalizations about the evolutionary processes that promote species divergence may also be potentially biased. Here we estimate a population-divergence model in montane grasshoppers from the sky islands of the Rocky Mountains. Because this region was directly impacted by Pleistocene glaciation, both the displacement into glacial refugia and recolonization of montane habitats may contribute to differentiation. Building on the tradition of using information from the genealogical relationships of alleles to infer the geography of divergence, here the additional consideration of the process of gene-lineage sorting is used to obtain a quantitative estimate of population relationships and historical associations (i.e., a population tree) from the gene trees of five anonymous nuclear loci and one mitochondrial locus in the broadly distributed species Melanoplus oregonensis. Three different approaches are used to estimate a model of population divergence; this comparison allows us to evaluate specific methodological assumptions that influence the estimated history of divergence. A model of population divergence was identified that significantly fits the data better compared to the other approaches, based on per-site likelihood scores of the multiple loci, and that provides clues about how divergence proceeded in M. oregonensis during the dynamic Pleistocene. Unlike the approaches that either considered only the most recent coalescence (i.e., information from a single individual per population) or did not

  3. Geographic Information Systems and Web Page Development

    NASA Technical Reports Server (NTRS)

    Reynolds, Justin

    2004-01-01

    The Facilities Engineering and Architectural Branch is responsible for the design and maintenance of buildings, laboratories, and civil structures. In order to improve efficiency and quality, the FEAB has dedicated itself to establishing a data infrastructure based on Geographic Information Systems, GIs. The value of GIS was explained in an article dating back to 1980 entitled "Need for a Multipurpose Cadastre which stated, "There is a critical need for a better land-information system in the United States to improve land-conveyance procedures, furnish a basis for equitable taxation, and provide much-needed information for resource management and environmental planning." Scientists and engineers both point to GIS as the solution. What is GIS? According to most text books, Geographic Information Systems is a class of software that stores, manages, and analyzes mapable features on, above, or below the surface of the earth. GIS software is basically database management software to the management of spatial data and information. Simply put, Geographic Information Systems manage, analyze, chart, graph, and map spatial information. At the outset, I was given goals and expectations from my branch and from my mentor with regards to the further implementation of GIs. Those goals are as follows: (1) Continue the development of GIS for the underground structures. (2) Extract and export annotated data from AutoCAD drawing files and construct a database (to serve as a prototype for future work). (3) Examine existing underground record drawings to determine existing and non-existing underground tanks. Once this data was collected and analyzed, I set out on the task of creating a user-friendly database that could be assessed by all members of the branch. It was important that the database be built using programs that most employees already possess, ruling out most AutoCAD-based viewers. Therefore, I set out to create an Access database that translated onto the web using Internet

  4. Correlation Assessment of Climate and Geographic Distribution of Tuberculosis Using Geographical Information System (GIS)

    PubMed Central

    BEIRANVAND, Reza; KARIMI, Asrin; DELPISHEH, Ali; SAYEHMIRI, Kourosh; SOLEIMANI, Samira; GHALAVANDI, Shahnaz

    2016-01-01

    Background: Tuberculosis (TB) spread pattern is influenced by geographic and social factors. Nowadays Geographic Information System (GIS) is one of the most important epidemiological instrumentation identifying high-risk population groups and geographic areas of TB. The aim of this study was to determine the correlation between climate and geographic distribution of TB in Khuzestan Province using GIS during 2005–2012. Methods: Through an ecological study, all 6363 patients with definite diagnosis of TB from 2005 until the end of September 2012 in Khuzestan Province, southern Iran were diagnosed. Data were recorded using TB- Register software. Tuberculosis incidence based on the climate and the average of annual rain was evaluated using GIS. Data were analyzed through SPSS software. Independent t-test, ANOVA, Linear regression, Pearson and Eta correlation coefficient with a significance level of less than 5% were used for the statistical analysis. Results: The TB incidence was different in various geographic conditions. The highest mean of TB cumulative incidence rate was observed in extra dry areas (P= 0.017). There was a significant inverse correlation between annual rain rate and TB incidence rate (R= −0.45, P= 0.001). The lowest TB incidence rate (0–100 cases per 100,000) was in areas with the average of annual rain more than 1000 mm (P= 0.003). Conclusion: The risk of TB has a strong relationship with climate and the average of annual rain, so that the risk of TB in areas with low annual rainfall and extra dry climate is more than other regions. Services and special cares to high-risk regions of TB are recommended. PMID:27057526

  5. Geographical Education and Society. Papers Presented at Commission on Geographical Education International Geographical Union (Sitges, Spain, August 25-31, 1986).

    ERIC Educational Resources Information Center

    Hernando, Agustin, Ed.

    Educational discourse is totally completely imbued with the values that affect the societies to which individuals belong. Those in the field of geographical education must examine those values in order to determine what type of geographical education is best for each society. The following papers contribute to this knowledge: "Presentation"…

  6. A situated knowledge representation of geographical information

    SciTech Connect

    Gahegan, Mark N.; Pike, William A.

    2006-11-01

    In this paper we present an approach to conceiving of, constructing and comparing the concepts developed and used by geographers, environmental scientists and other earth science researchers to help describe, analyze and ultimately understand their subject of study. Our approach is informed by the situations under which concepts are conceived and applied, captures details of their construction, use and evolution and supports their ultimate sharing along with the means for deep exploration of conceptual similarities and differences that may arise among a distributed network of researchers. The intent here is to support different perspectives onto GIS resources that researchers may legitimately take, and to capture and compute with aspects of epistemology, to complement the ontologies that are currently receiving much attention in the GIScience community.

  7. Air Force geographic information and analysis system

    SciTech Connect

    Henney, D.A.; Jansing, D.S.; Durfee, R.C.; Margle, S.M.; Till, L.E.

    1987-01-01

    A microcomputer-based geographic information and analysis system (GIAS) was developed to assist Air Force planners with environmental analysis, natural resources management, and facility and land-use planning. The system processes raster image data, topological data structures, and geometric or vector data similar to that produced by computer-aided design and drafting (CADD) systems, integrating the data where appropriate. Data types included Landsat imagery, scanned images of base maps, digitized point and chain features, topographic elevation data, USGS stream course data, highway networks, railroad networks, and land use/land cover information from USGS interpreted aerial photography. The system is also being developed to provide an integrated display and analysis capability with base maps and facility data bases prepared on CADD systems. 3 refs.

  8. Geographic Visualization of Power-Grid Dynamics

    SciTech Connect

    Sukumar, Sreenivas R.

    2015-06-18

    The visualization enables the simulation analyst to see changes in the frequency through time and space. With this technology, the analyst has a bird's eye view of the frequency at loads and generators as the simulated power system responds to the loss of a generator, spikes in load, and other contingencies. The significance of a contingency to the operation of an electrical power system depends critically on how the resulting tansients evolve in time and space. Consequently, these dynamic events can only be understood when seen in their proper geographic context. this understanding is indispensable to engineers working on the next generation of distributed sensing and control systems for the smart grid. By making possible a natural and intuitive presentation of dynamic behavior, our new visualization technology is a situational-awareness tool for power-system engineers.

  9. Distributed Object Oriented Geographic Information System

    1997-02-01

    This interactive, object-oriented, distributed Geographic Information System (GIS) uses the World Wibe Web (WWW) as application medium and distribution mechanism. The software provides distributed access to multiple geo-spatial databases and presents them as if they came from a single coherent database. DOOGIS distributed access comes not only in the form of multiple geo-spatial servers but can break down a single logical server into the constituent physical servers actually storing the data. The program provides formore » dynamic protocol resolution and content handling allowing unknown objects from a particular server to download their handling code. Security and access privileges are negotiated dynamically with each server contacted and each access attempt.« less

  10. Geographical information system for flight safety

    NASA Astrophysics Data System (ADS)

    Yamamoto, Hiromichi; Homma, Kohzo; Gomi, Hiromi; Kitagata, Satoru; Kumasaka, Kazuhiro; Oikawa, Tetsuya

    2003-03-01

    This paper proposes a geographical information system for terrain and obstacle awareness and alerting that extracts information from high-resolution satellite images. On-board terrain elevation databases are being increasingly used in aircraft terrain awareness and warning systems (TAWS), offering a step change in capability from the radar altimeter-based ground proximity warning system. However, to enhance the safety of flight of small aircraft and helicopters, in addition to pure topographic information a TAWS database should also contain significant man-made obstacles that present a collision hazard, such tall buildings and chimneys, communications masts and electrical power transmission lines. Another issue is keeping the terrain and obstacle database current, reflecting changes to features over time. High-resolution stereoscopic images remotely sensed from Earth orbit have great potential for addressing these issues. In this paper, some critical items are discussed and effective information processing schemes for extracting information relevant to flight safety from satellite images are proposed.

  11. Geographic Research in the USGS Western Region

    USGS Publications Warehouse

    Tongue, Mara

    2007-01-01

    The two geography research programs of the U.S. Geological Survey (USGS), Land Remote Sensing and Geographic Analysis and Monitoring, have very strong relevance to the USGS mission and science strategy. In the western United States, the particular niche of these geography programs is in connecting USGS science to people and communities. Reports from the National Academy of Sciences and other organizations invariably encourage the U.S. Geological Survey (USGS) to ensure the quality of its science while finding ways to make it more relevant to important societal issues. Much of the geography research conducted in the USGS Western Region does exactly that. In Menlo Park, California, the geography research team is focused on developing tools and techniques to help people assess risk from natural hazards and environmental impacts. In Flagstaff and Tucson, Arizona, geography scientists explore new ways to use remote sensing to help communities deal with environmental issues.

  12. Geographic Visualization of Power-Grid Dynamics

    2015-06-18

    The visualization enables the simulation analyst to see changes in the frequency through time and space. With this technology, the analyst has a bird's eye view of the frequency at loads and generators as the simulated power system responds to the loss of a generator, spikes in load, and other contingencies. The significance of a contingency to the operation of an electrical power system depends critically on how the resulting tansients evolve in time andmore » space. Consequently, these dynamic events can only be understood when seen in their proper geographic context. this understanding is indispensable to engineers working on the next generation of distributed sensing and control systems for the smart grid. By making possible a natural and intuitive presentation of dynamic behavior, our new visualization technology is a situational-awareness tool for power-system engineers.« less

  13. Comprehensive Monitoring for Heterogeneous Geographically Distributed Storage

    SciTech Connect

    Ratnikova, N.; Karavakis, E.; Lammel, S.; Wildish, T.

    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.

  14. The geographical distribution of Q fever

    PubMed Central

    Kaplan, Martin M.; Bertagna, P.

    1955-01-01

    The results of a WHO-assisted survey of the distribution of Q fever in 32 countries and an analysis of reports published to date indicate that Q fever exists in 51 countries on five continents. Q-fever infection was most often reported in man and the domestic ruminants, such as cattle, sheep, and goats. The disease was found to exist in most countries where investigations were carried out. Notable exceptions were Ireland, the Netherlands, New Zealand, Poland, and the Scandinavian countries. With the exception of Poland, where the results were inconclusive, all these countries import relatively few domestic ruminants—the most important animal reservoirs of human Q-fever infection. It seems, therefore, that the traffic of infected ruminants may be one of the most important, if not the most important, means for the geographical spread of Q fever. The importance, if any, of ticks associated with such traffic needs to be defined. PMID:13284560

  15. ORNL and the geographic information systems revolution

    SciTech Connect

    Dobson, J.E.; Durfee, R.C.

    1995-12-31

    Explorers from competing teams race to find a mysterious lost city in the heart of Africa. The American team is continuously in touch with its Houston home base through satellite communications. In flight, team leader Karen Ross displays a map of Africa on her computer screen and notes the multicolored lines suggesting different routes from city to city and into the rain forest. Each pathway is accompanied by a precise estimate of travel time to the final destination. Zooming in on the target area, she switches to satellite images and interprets them in shades of blue, purple, and green. At each checkpoint, the team reports its progress and gets a revised estimate of arrival time. Beset by difficulties, the explorers ask for a faster route, but the computer says the alternative is too dangerous. A simulation model with data representing geology, terrain, vegetation, weather, and many other geographic factors predicts local hazards, including the impending eruption of a nearby volcano. The Americans take the faster route anyway and beat the odds. This fictional account of emerging geographic information system (GIS) technologies comes from Michael Crichton`s 1980 novel Congo, which was made into a 1995 movie. The same technologies were highlighted in Clive Cussler`s 1988 techno-thriller Treasure. In reality, GIS technology began more than a quarter of a century ago at key universities and government laboratories in the United States and Canada. Since 1969, Oak Ridge National Laboratory has been among the leading institutions in this diverse, now booming field. GIS has been evolving through new forms and applications ever since.

  16. Stennis Space Center Environmental Geographic Information System

    NASA Technical Reports Server (NTRS)

    Lovely, Janette; Cohan, Tyrus

    2000-01-01

    As NASA's lead center for rocket propulsion testing, the John C. Stennis Space Center (SSC) monitors and assesses the off-site impacts of such testing through its Environmental Office (SSC-EO) using acoustical models and ancillary data. The SSC-EO has developed a geographical database, called the SSC Environmental Geographic Information System (SSC-EGIS), that covers an eight-county area bordering the NASA facility. Through the SSC-EGIS, the Enivronmental Office inventories, assesses, and manages the nearly 139,000 acres that comprise Stennis Space Center and its surrounding acoustical buffer zone. The SSC-EGIS contains in-house data as well as a wide range of data obtained from outside sources, including private agencies and local, county, state, and U.S. government agencies. The database comprises cadastral/geodetic, hydrology, infrastructure, geo-political, physical geography, and socio-economic vector and raster layers. The imagery contained in the database is varied, including low-resolution imagery, such as Landsat TM and SPOT; high-resolution imagery, such as IKONOS and AVIRIS; and aerial photographs. The SSC-EGIS has been an integral part of several major projects and the model upon which similar EGIS's will be developed for other NASA facilities. The Corps of Engineers utilized the SSC-EGIS in a plan to establish wetland mitigation sites within the SSC buffer zone. Mississippi State University employed the SSC-EGIS in a preliminary study to evaluate public access points within the buffer zone. The SSC-EO has also expressly used the SSC-EGIS to assess noise pollution modeling, land management/wetland mitigation assessment, environmental hazards mapping, and protected areas mapping for archaeological sites and for threatened and endangered species habitats. The SSC-EO has several active and planned projects that will also make use of the SSC-EGIS during this and the coming fiscal year.

  17. The NASA John C. Stennis Environmental Geographic Information System

    NASA Technical Reports Server (NTRS)

    Cohan, Tyrus; Grant, Kerry

    2002-01-01

    In addition to the Environmental Geographic Information System (EGIS) presentation, we will present two live demonstrations of a portion of the work being performed in support of environmental operations onsite and NASA-wide. These live demonstrations will showcase the NASA EGIS database through working versions of two software packages available from Environmental Systems Research Institute, Inc. (ESRI, Inc.): ArcIMS 3.0 and either ArcView 3.2a or ArcGIS 8.0.2. Using a standard web browser, the ArcIMS demo will allow users to access a project file containing several data layers found in the EGIS database. ArcIMS is configured so that a single computer can be used as the data server and as the user interface, which allows for maximum Internet security because the computer being used will not actually be connected to the World Wide Web. Further, being independent of the Internet, the demo will run at an increased speed. This demo will include several data layers that are specific to Stennis Space Center. The EGIS database demo is a representative portion of the entire EGIS project sent to NASA Headquarters last year. This demo contains data files that are readily available at various government agency Web sites for download. Although these files contain roads, rails, and other infrastructure details, they are generalized and at a small enough scale that they provide only a general idea of each NASA center's surroundings rather than specific details of the area.

  18. [Research progress on the risk factors of geographic tongue].

    PubMed

    Huamei, Yang; Yu, Zhou; Xin, Zeng; Ga, Liao; Qianming, Chen

    2015-02-01

    Geographic tongue, also called benign migratory glossitis, is a common and superficial benign inflammatory disorder that affects the tongue epithelium. The majority of geographic tongue lesions typically manifest as irregular central erythematous patches. These lesions, which are caused by the loss of filiform papillae, are defined by an elevated whitish band-like border that can change location, size, and pattern over a period of time. Histological observations of the oral mucosa affected by geographic tongue revealed nonspecific inflammation. Some reports described cases of migratory stomatitis, wherein lesions simultaneously manifested on the extra lingual oral mucosa. This condition is also called ectopic geographic tongue, which is clinically and histologically similar to the type normally confined to the tongue. In most cases, patients are asymptomatic and do not require treatment. The condition may spontaneously exhibit periods of remission and exacerbation with good prognosis. The specific etiology of geographic tongue remains unknown. Geographic tongue is age-related and is prevalent among young individuals. Various etiological factors that have been suggested in literature include immunological factors, genetic factors, atopic or allergic tendency, emotional stress, tobacco consumption, hormonal disturbances, and zinc deficiency. Geographic tongue may coexist with other disorders, such as fissured tongue, psoriasis, diabetes mellitus, gastroin- testinal diseases, burning mouth syndrome, and Down syndrome. Experts currently disagree on whether geographic tongue is an oral manifestation of psoriasis. Moreover, some scholars suggest that geographic tongue is a prestage of fissured tongue. The objective of this review is to summarize current research on risk factors of geographic tongue. PMID:25872308

  19. Geographic and Operational Site Parameters List (GOSPL) for the 2004 Composite Analysis

    SciTech Connect

    Last, George V.; Nichols, William E.; Kincaid, Charles T.

    2004-07-01

    This report briefly describes each of the key data fields, including the source(s) of data, and provides the resulting inputs to be used for the 2004 Composite Analysis. A master spreadsheet termed the Geographic and Operational Site Parameters List (GOSPL) was assembled to facilitate the generation of keyword input files containing general information on each waste site, its operational/disposal history, and its environmental settings (past, current, and future).

  20. Geographic variation in salt marsh structure and function.

    PubMed

    McCall, Brittany D; Pennings, Steven C

    2012-11-01

    We examined geographic variation in the structure and function of salt marsh communities along the Atlantic and Gulf coasts of the United States. Focusing on the arthropod community in the dominant salt marsh plant Spartina alterniflora, we tested two hypotheses: first, that marsh community structure varies geographically, and second, that two aspects of marsh function (response to eutrophication and addition of dead plant material) also vary geographically. We worked at eleven sites on the Gulf Coast and eleven sites on the Atlantic Coast, dividing each coast up into two geographic areas. Abiotic conditions (tidal range, soil organic content, and water content, but not soil salinity), plant variables (Spartina nitrogen content, height, cover of dead plant material, but not live Spartina percent cover or light interception), and arthropod variables (proportional abundances of predators, sucking herbivores, stem-boring herbivores, parasitoids, and detritivores, but not total arthropod numbers) varied among the four geographic regions. Latitude and mean tidal range explained much of this geographic variation. Nutrient enrichment increased all arthropod functional groups in the community, consistent with previous experimental results, and had similar effects in all geographic regions, contrary to our hypothesis, suggesting widespread consistency in this aspect of ecosystem function. The addition of dead plant material had surprisingly little effect on the arthropod community. Our results caution against the uncritical extrapolation of work done in one geographic region to another, but indicate that some aspects of marsh function may operate in similar ways in different geographic regions, despite spatial variation in community structure. PMID:22614261

  1. Geographical Topics Learning of Geo-Tagged Social Images.

    PubMed

    Zhang, Xiaoming; Ji, Shufan; Wang, Senzhang; Li, Zhoujun; Lv, Xueqiang

    2016-03-01

    With the availability of cheap location sensors, geotagging of images in online social media is very popular. With a large amount of geo-tagged social images, it is interesting to study how these images are shared across geographical regions and how the geographical language characteristics and vision patterns are distributed across different regions. Unlike textual document, geo-tagged social image contains multiple types of content, i.e., textual description, visual content, and geographical information. Existing approaches usually mine geographical characteristics using a subset of multiple types of image contents or combining those contents linearly, which ignore correlations between different types of contents, and their geographical distributions. Therefore, in this paper, we propose a novel method to discover geographical characteristics of geo-tagged social images using a geographical topic model called geographical topic model of social images (GTMSIs). GTMSI integrates multiple types of social image contents as well as the geographical distributions, in which image topics are modeled based on both vocabulary and visual features. In GTMSI, each region of the image would have its own topic distribution, and hence have its own language model and vision pattern. Experimental results show that our GTMSI could identify interesting topics and vision patterns, as well as provide location prediction and image tagging.

  2. Payment to health maintenance organizations and the geographic factor

    PubMed Central

    Rossiter, Louis F.; Adamache, Killard W.

    1990-01-01

    The adjusted average per capita cost (AAPCC) payment system for Medicare risk-based plans uses a county level geographic adjustment factor to account for differences in beneficiary costs across areas. The implications of abandoning the county unit as the basis of the geographic area are examined and the merging of counties to match the geographic definition used in the prospective payment system are considered. Year-to-year variation in a county AAPCC is inversely associated with county population size and, based on year-to-year AAPCC variation, 86 percent of all counties are too small to be used for the geographic adjustment. PMID:10113459

  3. Ecoregions and ecoregionalization: geographical and ecological perspectives

    USGS Publications Warehouse

    Loveland, Thomas R.; Merchant, James W.

    2005-01-01

    Ecoregions, i.e., areas exhibiting relative homogeneity of ecosystems, are units of analysis that are increasingly important in environmental assessment and management. Ecoregions provide a holistic framework for flexible, comparative analysis of complex environmental problems. Ecoregions mapping has intellectual foundations in both geography and ecology. However, a hallmark of ecoregions mapping is that it is a truly interdisciplinary endeavor that demands the integration of knowledge from a multitude of sciences. Geographers emphasize the role of place, scale, and both natural and social elements when delineating and characterizing regions. Ecologists tend to focus on environmental processes with special attention given to energy flows and nutrient cycling. Integration of disparate knowledge from the many key sciences has been one of the great challenges of ecoregions mapping, and may lie at the heart of the lack of consensus on the “optimal” approach and methods to use in such work. Through a review of the principal existing US ecoregion maps, issues that should be addressed in order to advance the state of the art are identified. Research related to needs, methods, data sources, data delivery, and validation is needed. It is also important that the academic system foster education so that there is an infusion of new expertise in ecoregion mapping and use.

  4. Do geographically isolated wetlands influence landscape functions?

    PubMed

    Cohen, Matthew J; Creed, Irena F; Alexander, Laurie; Basu, Nandita B; Calhoun, Aram J K; Craft, Christopher; D'Amico, Ellen; DeKeyser, Edward; Fowler, Laurie; Golden, Heather E; Jawitz, James W; Kalla, Peter; Kirkman, L Katherine; Lane, Charles R; Lang, Megan; Leibowitz, Scott G; Lewis, David Bruce; Marton, John; McLaughlin, Daniel L; Mushet, David M; Raanan-Kiperwas, Hadas; Rains, Mark C; Smith, Lora; Walls, Susan C

    2016-02-23

    Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological and habitat networks, contributing to landscape functions, such as flow generation, nutrient and sediment retention, and biodiversity support. GIWs constitute most of the wetlands in many North American landscapes, provide a disproportionately large fraction of wetland edges where many functions are enhanced, and form complexes with other water bodies to create spatial and temporal heterogeneity in the timing, flow paths, and magnitude of network connectivity. These attributes signal a critical role for GIWs in sustaining a portfolio of landscape functions, but legal protections remain weak despite preferential loss from many landscapes. GIWs lack persistent surface water connections, but this condition does not imply the absence of hydrological, biogeochemical, and biological exchanges with nearby and downstream waters. Although hydrological and biogeochemical connectivity is often episodic or slow (e.g., via groundwater), hydrologic continuity and limited evaporative solute enrichment suggest both flow generation and solute and sediment retention. Similarly, whereas biological connectivity usually requires overland dispersal, numerous organisms, including many rare or threatened species, use both GIWs and downstream waters at different times or life stages, suggesting that GIWs are critical elements of landscape habitat mosaics. Indeed, weaker hydrologic connectivity with downstream waters and constrained biological connectivity with other landscape elements are precisely what enhances some GIW functions and enables others. Based on analysis of wetland geography and synthesis of wetland functions, we argue that sustaining landscape functions requires conserving the entire continuum of wetland connectivity, including GIWs.

  5. Inferring social ties from geographic coincidences

    PubMed Central

    Crandall, David J.; Backstrom, Lars; Cosley, Dan; Suri, Siddharth; Huttenlocher, Daniel; Kleinberg, Jon

    2010-01-01

    We investigate the extent to which social ties between people can be inferred from co-occurrence in time and space: Given that two people have been in approximately the same geographic locale at approximately the same time, on multiple occasions, how likely are they to know each other? Furthermore, how does this likelihood depend on the spatial and temporal proximity of the co-occurrences? Such issues arise in data originating in both online and offline domains as well as settings that capture interfaces between online and offline behavior. Here we develop a framework for quantifying the answers to such questions, and we apply this framework to publicly available data from a social media site, finding that even a very small number of co-occurrences can result in a high empirical likelihood of a social tie. We then present probabilistic models showing how such large probabilities can arise from a natural model of proximity and co-occurrence in the presence of social ties. In addition to providing a method for establishing some of the first quantifiable estimates of these measures, our findings have potential privacy implications, particularly for the ways in which social structures can be inferred from public online records that capture individuals’ physical locations over time. PMID:21148099

  6. Object-oriented Geographic Information System Framework

    SciTech Connect

    Lurie, Gordon

    2003-03-01

    JeoViewer is an intelligent object-oriented geographic information system (GIS) framework written in Java that provides transparent linkage to any object’s data, behaviors, and optimized spatial geometry representation. Tools are provided for typical GIS functionality, data ingestion, data export, and integration with other frameworks. The primary difference between Jeo Viewer and traditional GIS systems is that traditional GIS systems offer static views of geo-spatial data while JeoViewer can be dynamically coupled to models and live data streams which dynamically change the state of the object which can be immediately represented in JeoViewer. Additionally, JeoViewer’s object-oriented paradigm provides a more natural representation of spatial data. A rich layer hierarchy allows arbitrary grouping of objects based on any relationship as well as the traditional GIS vertical ordering of objects. JeoViewer can run as a standalone product, extended with additional analysis functionality, or embedded in another framework.

  7. Inferring social ties from geographic coincidences.

    PubMed

    Crandall, David J; Backstrom, Lars; Cosley, Dan; Suri, Siddharth; Huttenlocher, Daniel; Kleinberg, Jon

    2010-12-28

    We investigate the extent to which social ties between people can be inferred from co-occurrence in time and space: Given that two people have been in approximately the same geographic locale at approximately the same time, on multiple occasions, how likely are they to know each other? Furthermore, how does this likelihood depend on the spatial and temporal proximity of the co-occurrences? Such issues arise in data originating in both online and offline domains as well as settings that capture interfaces between online and offline behavior. Here we develop a framework for quantifying the answers to such questions, and we apply this framework to publicly available data from a social media site, finding that even a very small number of co-occurrences can result in a high empirical likelihood of a social tie. We then present probabilistic models showing how such large probabilities can arise from a natural model of proximity and co-occurrence in the presence of social ties. In addition to providing a method for establishing some of the first quantifiable estimates of these measures, our findings have potential privacy implications, particularly for the ways in which social structures can be inferred from public online records that capture individuals' physical locations over time.

  8. Do geographically isolated wetlands influence landscape functions?

    USGS Publications Warehouse

    Cohen, Matthew J.; Creed, Irena F.; Alexander, Laurie C.; Basu, Nandita; Calhoun, Aram J. K.; Craft, Christopher; D’Amico, Ellen; DeKeyser, Edward S.; Fowler, Laurie; Golden, Heather E.; Jawitz, James W.; Kalla, Peter; Kirkman, L. Katherine; Lane, Charles R.; Lang, Megan; Leibowitz, Scott G.; Lewis, David Bruce; Marton, John; McLaughlin, Daniel L.; Mushet, David M.; Raanan-Kiperwas, Hadas; Rains, Mark C.; Smith, Lora; Walls, Susan C.

    2015-01-01

    Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological and habitat networks, contributing to landscape functions, such as flow generation, nutrient and sediment retention, and biodiversity support. GIWs constitute most of the wetlands in many North American landscapes, provide a disproportionately large fraction of wetland edges where many functions are enhanced, and form complexes with other water bodies to create spatial and temporal heterogeneity in the timing, flow paths, and magnitude of network connectivity. These attributes signal a critical role for GIWs in sustaining a portfolio of landscape functions, but legal protections remain weak despite preferential loss from many landscapes. GIWs lack persistent surface water connections, but this condition does not imply the absence of hydrological, biogeochemical, and biological exchanges with nearby and downstream waters. Although hydrological and biogeochemical connectivity is often episodic or slow (e.g., via groundwater), hydrologic continuity and limited evaporative solute enrichment suggest both flow generation and solute and sediment retention. Similarly, whereas biological connectivity usually requires overland dispersal, numerous organisms, including many rare or threatened species, use both GIWs and downstream waters at different times or life stages, suggesting that GIWs are critical elements of landscape habitat mosaics. Indeed, weaker hydrologic connectivity with downstream waters and constrained biological connectivity with other landscape elements are precisely what enhances some GIW functions and enables others. Based on analysis of wetland geography and synthesis of wetland functions, we argue that sustaining landscape functions requires conserving the entire continuum of wetland connectivity, including GIWs.

  9. Genetic variation and geographic distribution of megalocytiviruses.

    PubMed

    Song, Jun-Young; Kitamura, Shin-Ichi; Jung, Sung-Ju; Miyadai, Toshiaki; Tanaka, Shinji; Fukuda, Yutaka; Kim, Seok-Ryel; Oh, Myung-Joo

    2008-02-01

    Viruses belonging to the genus Megalocytivirus in the family Iridoviridae have caused mass mortalities in marine and freshwater fish in Asian countries. In this study, partial major capsid protein (MCP) gene of seven Japanese and six Korean megalocytiviruses was sequenced and compared with the known megalocytiviruses to evaluate genetic variation and geographic distribution of the viruses. Comparison of MCP gene nucleotide sequences revealed sequence identity of 92.8% or greater among these 48 isolates. A phylogenetic tree clearly revealed three clusters: genotype I including nine Japanese isolates, thirteen Korean isolates, one Chinese isolates, one Thailand isolate and one South China Sea isolate; genotype II including five freshwater fish isolates in Southeast Asian countries and Australia; and the remaining genotype III mainly consisted of flatfish isolate in Korea and China. This suggests that viruses belonging to the genotype I widely distribute among various fish species in many Asian countries. Conversely, the epidemic viruses belonged to genotype II and III are may be still locally spreading and constrained in their prevalence to the limited host fish species, i.e., genotype II viruses mainly distribute in Southeast Asian countries, whereas genotype III viruses distribute in flatfish species in Korea and China.

  10. Geographic information system based manure application plan.

    PubMed

    Basnet, Badri B; Apan, Armando A; Raine, Steven R

    2002-02-01

    A geographic information system (GIS) based manure application plan has been developed for the site-specific application of animal waste to agricultural fields in the Westbrook sub-catchment of the Murray-Darling Basin, south-east Queensland, Australia. Sites suitable for animal waste application were identified using a GIS based weighted linear combination (WLC) model. The degree of land suitability for animal waste application was determined using a range of social, economic, environmental, and agricultural factors. As eutrophication and toxic blue-green algae blooms are a known problem in the catchment, the manure application rates were limited to the rate of crop phosphorus removal. Maximum manure application rate was calculated spatially by taking the crop nutrient (P2O5) requirement and the manure nutrient (P2O5) content into account. The environmental suitability of the fields receiving animal waste was considered in prescribing the final application rate of solid and liquid manures generated by local animal production facilities. The degree of site suitability of the agricultural fields was also used to suggest manure management practices to minimise the socio-environmental risks and increase the nutrient use efficiency of the applied manure. The amount of ammonium nitrogen (NH4-N) that would be added to the soil by satisfying the P2O5 requirement using manure sources was also calculated and an applied NH4-N map was created. This map could be used to assist farmers identify additional nitrogen requirements after manure application. PMID:11995243

  11. Geographic Clusters of Primary Biliary Cirrhosis

    PubMed Central

    Abu-Mouch, Saif; Selmi, Carlo; Benson, Gordon D.; Kenny, Thomas P.; Invernizzi, Pietro; Zuin, Massimo; Podda, Mauro; Rossaro, Lorenzo; Gershwin, M. Eric

    2003-01-01

    Genetic and environmental factors have been widely suggested to contribute to the pathogenesis of primary biliary cirrhosis (PBC), an autoimmune disease of unknown etiology leading to destruction of small bile ducts. Interestingly, epidemiologic data indicate a variable prevalence of the disease in different geographical areas. The study of clusters of PBC may provide clues as to possible triggers in the induction of immunopathology. We report herein four such unique PBC clusters that suggest the presence of both genetic and environmental factors in the induction of PBC. The first cluster is represented by a family of ten siblings of Palestinian origin that have an extraordinary frequency of PBC (with 5/8 sisters having the disease). Second, we describe the cases of a husband and wife, both having PBC. A family in which PBC was diagnosed in two genetically unrelated individuals, who lived in the same household, represents the third cluster. Fourth, we report a high prevalence of PBC cases in a very small area in Alaska. Although these data are anedoctal, the study of a large number of such clusters may provide a tool to estimate the roles of genetics and environment in the induction of autoimmunity. PMID:14768943

  12. Object-oriented Geographic Information System Framework

    2003-03-01

    JeoViewer is an intelligent object-oriented geographic information system (GIS) framework written in Java that provides transparent linkage to any object’s data, behaviors, and optimized spatial geometry representation. Tools are provided for typical GIS functionality, data ingestion, data export, and integration with other frameworks. The primary difference between Jeo Viewer and traditional GIS systems is that traditional GIS systems offer static views of geo-spatial data while JeoViewer can be dynamically coupled to models and live datamore » streams which dynamically change the state of the object which can be immediately represented in JeoViewer. Additionally, JeoViewer’s object-oriented paradigm provides a more natural representation of spatial data. A rich layer hierarchy allows arbitrary grouping of objects based on any relationship as well as the traditional GIS vertical ordering of objects. JeoViewer can run as a standalone product, extended with additional analysis functionality, or embedded in another framework.« less

  13. Genetic characterization of Bombyx mori (Lepidoptera: Bombycidae) breeding and hybrid lines with different geographic origins.

    PubMed

    Furdui, Emilia M; Mărghitaş, Liviu A; Dezmirean, Daniel S; Paşca, Ioan; Pop, Iulia F; Erler, Silvio; Schlüns, Ellen A

    2014-01-01

    The domesticated silkworm Bombyx mori L. comprises a large number of geographical breeds and hybrid lines. Knowing the genetic structure of those may provide information to improve the conservation of commercial lines by estimating inbreeding over generations and the consequences of excessive use of those lineages. Here, we analyzed the genetic diversity of seven breeds and eight hybrid lines from Eastern Europe and Asia using highly polymorphic microsatellites markers to determine its genetical impact on their use in global breeding programs. No consistent pattern of deviation from Hardy-Weinberg equilibrium was found for most breed and hybrids; and the absence of a linkage disequilibrium also suggests that the strains are in equilibrium. A principal coordinate analysis revealed a clear separation of two silkworm breeds from the rest: one (IBV) originated from India and the other one (RG90) from Romania/Japan. The tendency of the other breeds from different geographic origins to cluster together in a general mix might be due to similar selection pressures (climate and anthropogenic factors) in different geographic locations. Phylogenetic analyses grouped the different silkworm breeds but not the hybrids according to their geographic origin and confirmed the pattern found in the principal coordinate analysis.

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

    PubMed Central

    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

  15. Genetic characterization of Bombyx mori (Lepidoptera: Bombycidae) breeding and hybrid lines with different geographic origins.

    PubMed

    Furdui, Emilia M; Mărghitaş, Liviu A; Dezmirean, Daniel S; Paşca, Ioan; Pop, Iulia F; Erler, Silvio; Schlüns, Ellen A

    2014-01-01

    The domesticated silkworm Bombyx mori L. comprises a large number of geographical breeds and hybrid lines. Knowing the genetic structure of those may provide information to improve the conservation of commercial lines by estimating inbreeding over generations and the consequences of excessive use of those lineages. Here, we analyzed the genetic diversity of seven breeds and eight hybrid lines from Eastern Europe and Asia using highly polymorphic microsatellites markers to determine its genetical impact on their use in global breeding programs. No consistent pattern of deviation from Hardy-Weinberg equilibrium was found for most breed and hybrids; and the absence of a linkage disequilibrium also suggests that the strains are in equilibrium. A principal coordinate analysis revealed a clear separation of two silkworm breeds from the rest: one (IBV) originated from India and the other one (RG90) from Romania/Japan. The tendency of the other breeds from different geographic origins to cluster together in a general mix might be due to similar selection pressures (climate and anthropogenic factors) in different geographic locations. Phylogenetic analyses grouped the different silkworm breeds but not the hybrids according to their geographic origin and confirmed the pattern found in the principal coordinate analysis. PMID:25502023

  16. Assessment of the Homogeneity of Volunteered Geographic Information in South Africa

    NASA Astrophysics Data System (ADS)

    Siebritz, L.; Sithole, G.; Zlatanova, S.

    2012-08-01

    The potential for volunteer groups to contribute geographic data to National Mapping Agencies has been widely recognised. Several investigations have been done to determine the geometric accuracy of this data for the purposes of national mapping. Beyond accuracy, from a production perspective National Mapping Agencies will also be interested in the sufficiency and uniformity of the data. This paper presents an investigation of whether presently geographic data generated by volunteers is uniform across a country and whether the rate of production of data is consistent. For the purpose of the test, changes in data of South Africa from OpenStreetMap are analysed for the period 2006 to 2011. Here only point and line data are considered. The results generally show that the rate at which data is generated varies in space and time. The results also confirm that volunteers emphasise on the capture of certain information and that the capture doesn't average out as might be expected. The results also showed that social events, such as a World Cup, also have the effect of spurring the generation of volunteer geographic data. The implication of these results for National Mapping Agencies is that they cannot treat volunteer geographic information as being of a uniform standard. How National Mapping Agencies respond to this will have to be the subject of other investigations.

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

    PubMed Central

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

    2015-01-01

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

  18. Geographic variation and neighborhood factors are associated with low rates of pre-end-stage renal disease nephrology care.

    PubMed

    Hao, Hua; Lovasik, Brendan P; Pastan, Stephen O; Chang, Howard H; Chowdhury, Ritam; Patzer, Rachel E

    2015-09-01

    Geographic variation of pre-end-stage renal disease (pre-ESRD) nephrology care has not been studied across the United States. Here we sought to identify geographic differences in pre-ESRD care, assess for county-level geographic and sociodemographic risk factors, and correlate with patient outcomes using facility-level mortality. Patients from 5387 dialysis facilities across the United States from 2007 to 2010 were included from the Dialysis Facility Report. Marginal generalized estimating equations were used for modeling with geographic cluster analysis to detect clusters of facilities with low rates of pre-ESRD care. On average, 67% of patients received pre-ESRD care in the United States but with significant variability across regions ranging from 3 to 99%. Five geographic clusters of facilities with low rates of pre-ESRD care were the metropolitan areas of San Francisco, Los Angeles, Chicago, Miami, and Baltimore, along with Southern states along the Mississippi River. Dialysis facilities with the lowest rates of pre-ESRD care were more likely to be located in urban counties with high African-American populations and low educational attainment. A 10% higher proportion of patients receiving pre-ESRD care was associated with 1.3% lower patient mortality as reflected by facility-level mortality. Thus, geographic and sociodemographic factors can be used to design quality improvement initiatives to increase access to nephrology care nationwide and improve patient outcomes. PMID:25901471

  19. 29 CFR 776.7 - Geographical scope of coverage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Determined § 776.7 Geographical scope of coverage. (a) The geographical areas within which the employees are... possession of the United States.” (b) Under the definitions in paragraph (a) of this section, employees... on the same basis as employees working in any of the 50 States. 20 Congress did not exercise...

  20. Geographical Information Systems: A Tool for Institutional Research.

    ERIC Educational Resources Information Center

    Prather, James E.; Carlson, Christina E.

    This paper addresses the application of Geographical Information Systems (GIS), a computerized tool for associating key information by geographical location, to the institutional research function at institutions of higher education. The first section investigates the potential of GIS as an analytical and planning tool for institutional…

  1. 47 CFR 76.984 - Geographically uniform rate structure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Geographically uniform rate structure. 76.984... MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Cable Rate Regulation § 76.984 Geographically uniform rate structure. (a) The rates charged by cable operators for basic service, cable programming service,...

  2. 47 CFR 76.984 - Geographically uniform rate structure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Geographically uniform rate structure. 76.984... MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Cable Rate Regulation § 76.984 Geographically uniform rate structure. (a) The rates charged by cable operators for basic service, cable programming service,...

  3. 47 CFR 27.805 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES 1.4 GHz Band § 27.805 Geographic partitioning and spectrum disaggregation. An entity that acquires a portion of a 1.4 GHz band licensee's... 47 Telecommunication 2 2013-10-01 2013-10-01 false Geographic partitioning and...

  4. 47 CFR 27.805 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES 1.4 GHz Band § 27.805 Geographic partitioning and spectrum disaggregation. An entity that acquires a portion of a 1.4 GHz band licensee's... 47 Telecommunication 2 2014-10-01 2014-10-01 false Geographic partitioning and...

  5. 47 CFR 27.904 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES 1670-1675 MHz Band § 27.904 Geographic partitioning and spectrum disaggregation. An entity that acquires a portion of a 1670-1675 MHz band licensee's... 47 Telecommunication 2 2013-10-01 2013-10-01 false Geographic partitioning and...

  6. 47 CFR 27.904 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES 1670-1675 MHz Band § 27.904 Geographic partitioning and spectrum disaggregation. An entity that acquires a portion of a 1670-1675 MHz band licensee's... 47 Telecommunication 2 2014-10-01 2014-10-01 false Geographic partitioning and...

  7. Third World Films: A Strategy for Promoting Geographic Understanding.

    ERIC Educational Resources Information Center

    Macdonald, Gerald M.

    1990-01-01

    Suggests that feature films produced in developing nations can serve as an aid to geographic instruction because they visually represent conditions of daily life. Uses two films, "Salaam Bombay" and "Sugar Cane Alley," to illustrate geographic understanding. Appendices include information on film distributors, background readings, and study guides…

  8. Lived and Imagined: Information and Storytelling in Geographic Systems

    ERIC Educational Resources Information Center

    Kabisch, Eric Alan

    2011-01-01

    This dissertation investigates the relationship between storytelling and information in the narration of geographic space. While storytelling has historically shaped our understanding of geography, modern practices in data collection, cartography, and geographic visualization enable one-way forms of representation that remove the negotiation and…

  9. Issues Surrounding the Use of Virtual Reality in Geographic Education

    ERIC Educational Resources Information Center

    Lisichenko, Richard

    2015-01-01

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

  10. Connecting the Demographic Dots: Geographic Mobility and Birth Intentions

    ERIC Educational Resources Information Center

    Myers, Scott M.

    2010-01-01

    Having a child is a major determinant of geographic mobility. Little is known, however, about the opposite process--whether geographic mobility is a determinant of fertility. Drawing on social and human capital theories and research on fertility and migration to develop competing hypotheses, the author examines the effects of mobility on changes…

  11. Geographic Distribution and Expansion of Human Lyme Disease, United States.

    PubMed

    Kugeler, Kiersten J; Farley, Grace M; Forrester, Joseph D; Mead, Paul S

    2015-08-01

    Lyme disease occurs in specific geographic regions of the United States. We present a method for defining high-risk counties based on observed versus expected number of reported human Lyme disease cases. Applying this method to successive periods shows substantial geographic expansion of counties at high risk for Lyme disease.

  12. Geographic Differences in the Earnings of Economics Majors

    ERIC Educational Resources Information Center

    Winters, John V.; Xu, Weineng

    2014-01-01

    Economics has been shown to be a relatively high-earning college major, but geographic differences in earnings have been largely overlooked. The authors of this article use the American Community Survey to examine geographic differences in both absolute earnings and relative earnings for economics majors. They find that there are substantial…

  13. Applications of Geographic Research: Viewpoints from Michigan State University.

    ERIC Educational Resources Information Center

    Winters, Harold A., Ed.; Winters, Marjorie K., Ed.

    Eighteen essays discuss applications of geographic research covering a variety of topics and methodologies. All authors are faculty, graduates, or graduate students of the geography department at Michigan State University. The most frequently discussed themes include economic, political, social, and medical uses of geographic research. Two papers…

  14. Empirical analytic transformations between geographic and corrected geomagnetic coordinates

    NASA Technical Reports Server (NTRS)

    Comfort, R. H.

    1970-01-01

    Based upon a mathematical model of contours of constant corrected geomagnetic latitude in a polar projection of geographic coordinates, analytic equations are developed for converting geographic coordinates to corrected geomagnetic coordinates and vice versa. The equations were programmed for use on a small computer. This treatment is restricted to the Northern Hemisphere.

  15. Geographic Information Systems: A Tool for Rural Community Research.

    ERIC Educational Resources Information Center

    Dewees, Sarah; Collins, Timothy

    1998-01-01

    Describes the use of geographic information systems (GIS) by a "local learning team" to map socioeconomic patterns in Jackson County, Kentucky, and to evaluate the distribution of local funding and the geographic equity of representation related to the Empowerment Zone/Enterprise Community program. Discusses advantages and disadvantages to using…

  16. Geographic information system index for the State of Tennessee

    USGS Publications Warehouse

    Barron, William R.; Norris, Pamela G.

    1989-01-01

    Recently the use of Geographical Information Systems (GIS) has increased within Tennessee. As a result, the U.S. Geological Survey, the Tennessee State Planning Office, and the Tennessee Comptroller of the Treasury entered into an agreement to conduct a survey of GIS users within the State. Two hundred and sixty three agencies were contacted. One hundred and thirty-nine agencies maintained one or more computer system (including personal computers). Twenty-five agencies used GIS software. The number of coverages or layers that exist upon completion of the survey as computerized digital data for Tennessee was 4,741. One hundred and twenty location-specific data bases were available. The U.S. Geological Survey, National Mapping Division map accuracy standards and digital cartographic data standards were included as minimum guidelines for GIS users. General data sharing techniques were described. The most common one was the use of magnetic tapes. A GIS index data base containing the survey data was built for inquiries. A 7.5 minute quadrangle coverage of Tennessee was created to allow for identification on a quadrangle basis of existing coverages contained in the GIS data base. (USGS)

  17. KBGIS-II: A knowledge-based geographic information system

    NASA Technical Reports Server (NTRS)

    Smith, Terence; Peuquet, Donna; Menon, Sudhakar; Agarwal, Pankaj

    1986-01-01

    The architecture and working of a recently implemented Knowledge-Based Geographic Information System (KBGIS-II), designed to satisfy several general criteria for the GIS, is described. The system has four major functions including query-answering, learning and editing. The main query finds constrained locations for spatial objects that are describable in a predicate-calculus based spatial object language. The main search procedures include a family of constraint-satisfaction procedures that use a spatial object knowledge base to search efficiently for complex spatial objects in large, multilayered spatial data bases. These data bases are represented in quadtree form. The search strategy is designed to reduce the computational cost of search in the average case. The learning capabilities of the system include the addition of new locations of complex spatial objects to the knowledge base as queries are answered, and the ability to learn inductively definitions of new spatial objects from examples. The new definitions are added to the knowledge base by the system. The system is performing all its designated tasks successfully. Future reports will relate performance characteristics of the system.

  18. Geographic setting influences Great Lakes beach microbiological water quality

    USGS Publications Warehouse

    Haack, Sheridan K.; Fogarty, Lisa R.; Stelzer, Erin A.; Fuller, Lori M.; Brennan, Angela K.; Isaacs, Natasha M.; Johnson, Heather E.

    2013-01-01

    Understanding of factors that influence Escherichia coli (EC) and enterococci (ENT) concentrations, pathogen occurrence, and microbial sources at Great Lakes beaches comes largely from individual beach studies. Using 12 representative beaches, we tested enrichment cultures from 273 beach water and 22 tributary samples for EC, ENT, and genes indicating the bacterial pathogens Shiga-toxin producing E. coli (STEC), Shigella spp., Salmonella spp, Campylobacter jejuni/coli, and methicillin-resistant Staphylococcus aureus, and 108–145 samples for Bacteroides human, ruminant, and gull source-marker genes. EC/ENT temporal patterns, general Bacteroides concentration, and pathogen types and occurrence were regionally consistent (up to 40 km), but beach catchment variables (drains/creeks, impervious surface, urban land cover) influenced exceedances of EC/ENT standards and detections of Salmonella and STEC. Pathogen detections were more numerous when the EC/ENT Beach Action Value (but not when the Geometric Mean and Statistical Threshold Value) was exceeded. EC, ENT, and pathogens were not necessarily influenced by the same variables. Multiple Bacteroides sources, varying by date, occurred at every beach. Study of multiple beaches in different geographic settings provided new insights on the contrasting influences of regional and local variables, and a broader-scale perspective, on significance of EC/ENT exceedances, bacterial sources, and pathogen occurrence.

  19. Geographic setting influences Great Lakes beach microbiological water quality.

    PubMed

    Haack, Sheridan K; Fogarty, Lisa R; Stelzer, Erin A; Fuller, Lori M; Brennan, Angela K; Isaacs, Natasha M; Johnson, Heather E

    2013-01-01

    Understanding of factors that influence Escherichia coli (EC) and enterococci (ENT) concentrations, pathogen occurrence, and microbial sources at Great Lakes beaches comes largely from individual beach studies. Using 12 representative beaches, we tested enrichment cultures from 273 beach water and 22 tributary samples for EC, ENT, and genes indicating the bacterial pathogens Shiga-toxin producing E. coli (STEC), Shigella spp. , Salmonella spp , Campylobacter jejuni/coli , and methicillin-resistant Staphylococcus aureus , and 108-145 samples for Bacteroides human, ruminant, and gull source-marker genes. EC/ENT temporal patterns, general Bacteroides concentration, and pathogen types and occurrence were regionally consistent (up to 40 km), but beach catchment variables (drains/creeks, impervious surface, urban land cover) influenced exceedances of EC/ENT standards and detections of Salmonella and STEC. Pathogen detections were more numerous when the EC/ENT Beach Action Value (but not when the Geometric Mean and Statistical Threshold Value) was exceeded. EC, ENT, and pathogens were not necessarily influenced by the same variables. Multiple Bacteroides sources, varying by date, occurred at every beach. Study of multiple beaches in different geographic settings provided new insights on the contrasting influences of regional and local variables, and a broader-scale perspective, on significance of EC/ENT exceedances, bacterial sources, and pathogen occurrence.

  20. Climate change and micro-geographic variation in laying date.

    PubMed

    Møller, Anders Pape

    2008-04-01

    Climate change has been shown to affect the timing of reproduction, with earlier reproduction being associated with an increase in temperature. Changes in the timing of reproduction arise from changes in food availability as well as other factors, and differences in the timing of reproduction among sites may cause sites with early reproduction to contribute disproportionately to local recruitment. In this study, spatial variation in the laying date of barn swallows Hirundo rustica at 39 sites in a 45-km2 study area during the period 1971-2004 was used to investigate micro-geographic patterns in the timing of breeding. I found that individuals breeding at sites with early reproduction had a disproportionately large reproductive success. Early sites were characterized by early plant phenology, as determined by the date of leafing of the broad-leaved elm Ulmus glabra and date of flowering of the snowdrop Galanthus nivalis during a single year. Such early sites showed greater advancement in laying date between 1971 and 2004 than the average site. Early sites were also generally occupied during more years by a larger number of breeders than were late sites. Breeders at early sites produced more fledglings, and breeders at such sites were characterized by a smaller adult body size and larger secondary sexual characters than individuals at the average site. These observations are consistent with the hypothesis that temporal changes in the timing of reproduction occur as a consequence of differential recruitment at phenologically early sites that produce disproportionately large numbers of offspring.

  1. Do geographically isolated wetlands influence landscape functions?

    PubMed

    Cohen, Matthew J; Creed, Irena F; Alexander, Laurie; Basu, Nandita B; Calhoun, Aram J K; Craft, Christopher; D'Amico, Ellen; DeKeyser, Edward; Fowler, Laurie; Golden, Heather E; Jawitz, James W; Kalla, Peter; Kirkman, L Katherine; Lane, Charles R; Lang, Megan; Leibowitz, Scott G; Lewis, David Bruce; Marton, John; McLaughlin, Daniel L; Mushet, David M; Raanan-Kiperwas, Hadas; Rains, Mark C; Smith, Lora; Walls, Susan C

    2016-02-23

    Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological and habitat networks, contributing to landscape functions, such as flow generation, nutrient and sediment retention, and biodiversity support. GIWs constitute most of the wetlands in many North American landscapes, provide a disproportionately large fraction of wetland edges where many functions are enhanced, and form complexes with other water bodies to create spatial and temporal heterogeneity in the timing, flow paths, and magnitude of network connectivity. These attributes signal a critical role for GIWs in sustaining a portfolio of landscape functions, but legal protections remain weak despite preferential loss from many landscapes. GIWs lack persistent surface water connections, but this condition does not imply the absence of hydrological, biogeochemical, and biological exchanges with nearby and downstream waters. Although hydrological and biogeochemical connectivity is often episodic or slow (e.g., via groundwater), hydrologic continuity and limited evaporative solute enrichment suggest both flow generation and solute and sediment retention. Similarly, whereas biological connectivity usually requires overland dispersal, numerous organisms, including many rare or threatened species, use both GIWs and downstream waters at different times or life stages, suggesting that GIWs are critical elements of landscape habitat mosaics. Indeed, weaker hydrologic connectivity with downstream waters and constrained biological connectivity with other landscape elements are precisely what enhances some GIW functions and enables others. Based on analysis of wetland geography and synthesis of wetland functions, we argue that sustaining landscape functions requires conserving the entire continuum of wetland connectivity, including GIWs. PMID:26858425

  2. Automation technology using Geographic Information System (GIS)

    NASA Technical Reports Server (NTRS)

    Brooks, Cynthia L.

    1994-01-01

    Airport Surface Movement Area is but one of the actions taken to increase the capacity and safety of existing airport facilities. The System Integration Branch (SIB) has designed an integrated system consisting of an electronic moving display in the cockpit, and includes display of taxi routes which will warn controllers and pilots of the position of other traffic and warning information automatically. Although, this system has in test simulation proven to be accurate and helpful; the initial process of obtaining an airport layout of the taxi-routes and designing each of them is a very tedious and time-consuming process. Other methods of preparing the display maps are being researched. One such method is the use of the Geographical Information System (GIS). GIS is an integrated system of computer hardware and software linking topographical, demographic and other resource data that is being referenced. The software can support many areas of work with virtually unlimited information compatibility due to the system's open architecture. GIS will allow us to work faster with increased efficiency and accuracy while providing decision making capabilities. GIS is currently being used at the Langley Research Center with other applications and has been validated as an accurate system for that task. GIS usage for our task will involve digitizing aerial photographs of the topology for each taxi-runway and identifying each position according to its specific spatial coordinates. The information currently being used can be integrated with the GIS system, due to its ability to provide a wide variety of user interfaces. Much more research and data analysis will be needed before this technique will be used, however we are hopeful this will lead to better usage of man-power and technological capabilities for the future.

  3. Monitoring bird populations in small geographic areas

    USGS Publications Warehouse

    Dunn, E.H.; Bart, J.; Collins, B.T.; Craig, B.; Dale, B.; Downes, C.M.; Francis, C.M.; Woodley, S.; Zorn, P.

    2006-01-01

    Numerous methods exist for monitoring bird populations, and there is a large literature describing them. There are few resources, however, that provide comprehensive advice on every step of organizing and carrying out a survey, from the early stages of planning to final use of the data. Even fewer resources are designed to meet the needs of a wide variety of potential users, from amateurs interested in change of bird life in a local study preserve to professionals testing hypotheses on the response of birds to habitat management, although much of the advice should be the same for every monitoring program. Whether survey objectives are very modest or rigorously scientific, samples must be sufficiently numerous and well distributed to provide meaningful results, and the survey should be well designed to ensure that the money and effort going into it are not wasted. This document is intended to be a complete resource for anyone planning to organize monitoring of noncolonial landbirds within a relatively small geographic area (e.g., from the size of a woodlot to a large park). The first of its two parts provides background explaining the importance of good study design and gives specific advice on all aspects of project planning and execution of high-quality data collection for the purpose of hypothesis testing. The second part is self-contained and nontechnical and describes complete plans for a site-specific checklist survey, suitable for addressing monitoring questions frequently asked by amateurs and for involvement of volunteers in data collection. Throughout are references to additional resources, from background literature to sources of existing survey protocols, analysis software, and tools for archiving data.

  4. Illuminating geographical patterns in species' range shifts.

    PubMed

    Grenouillet, Gaël; Comte, Lise

    2014-10-01

    would greatly benefit from identifying both the geographical patterns and the species' traits associated with complex modifications of species' distributions in response to global changes.

  5. Illuminating geographical patterns in species' range shifts.

    PubMed

    Grenouillet, Gaël; Comte, Lise

    2014-10-01

    would greatly benefit from identifying both the geographical patterns and the species' traits associated with complex modifications of species' distributions in response to global changes. PMID:24616088

  6. Do geographically isolated wetlands influence landscape functions?

    PubMed Central

    Cohen, Matthew J.; Creed, Irena F.; Alexander, Laurie; Basu, Nandita B.; Calhoun, Aram J. K.; Craft, Christopher; D’Amico, Ellen; DeKeyser, Edward; Fowler, Laurie; Golden, Heather E.; Jawitz, James W.; Kalla, Peter; Kirkman, L. Katherine; Lane, Charles R.; Lang, Megan; Leibowitz, Scott G.; Lewis, David Bruce; Marton, John; McLaughlin, Daniel L.; Mushet, David M.; Raanan-Kiperwas, Hadas; Rains, Mark C.; Smith, Lora; Walls, Susan C.

    2016-01-01

    Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological and habitat networks, contributing to landscape functions, such as flow generation, nutrient and sediment retention, and biodiversity support. GIWs constitute most of the wetlands in many North American landscapes, provide a disproportionately large fraction of wetland edges where many functions are enhanced, and form complexes with other water bodies to create spatial and temporal heterogeneity in the timing, flow paths, and magnitude of network connectivity. These attributes signal a critical role for GIWs in sustaining a portfolio of landscape functions, but legal protections remain weak despite preferential loss from many landscapes. GIWs lack persistent surface water connections, but this condition does not imply the absence of hydrological, biogeochemical, and biological exchanges with nearby and downstream waters. Although hydrological and biogeochemical connectivity is often episodic or slow (e.g., via groundwater), hydrologic continuity and limited evaporative solute enrichment suggest both flow generation and solute and sediment retention. Similarly, whereas biological connectivity usually requires overland dispersal, numerous organisms, including many rare or threatened species, use both GIWs and downstream waters at different times or life stages, suggesting that GIWs are critical elements of landscape habitat mosaics. Indeed, weaker hydrologic connectivity with downstream waters and constrained biological connectivity with other landscape elements are precisely what enhances some GIW functions and enables others. Based on analysis of wetland geography and synthesis of wetland functions, we argue that sustaining landscape functions requires conserving the entire continuum of wetland connectivity, including GIWs. PMID:26858425

  7. Geographical pathology as a method for detecting occupational cancer.

    PubMed

    Goldsmith, J R

    1977-08-01

    Geographical pathology points to environmental factors in cancer and helps estimate their potential magnitude. An occupational contribution was established by 1972 for cancer of the mouth, lung, bladder, and skin. Additionally partly based on geographical pathology, an occupational etiology is accepted for some cancer of nasopharynx, brain, liver, pleura, nasal sinus, bone and bone marrow, and possibly stomach. For identifying new occupational factors based on geographical comparisons, both an optimal size of work force to be followed-up and a sufficiently high proportion of work force in the geographical unit's population are necessary. Hypothetical variations based on 30-year follow-up of asbestos workers illustrate this. Cancer surveys and registries can greatly facilitate detection of occupational cancer. Evidence for occupational factors in the geographical pathology of lymphosarcoma is briefly summarized; but no conclusions are reached.

  8. Development of Virtual Geographic Environments and Geography Research

    NASA Astrophysics Data System (ADS)

    Huang, Fengru; Lin, Hui; Chen, Bin

    Geographic environment is a combination of natural and cultural environments under which humans survive. Virtual Geographic Environment (VGE) is a new multi-disciplinary initiative that links geosciences, geographic information sciences and information technologies. A VGE is a virtual representation of the natural world that enables a person to explore and interact with vast amounts of natural and cultural information on the physical and cultural environment in cyberspace. Virtual Geography and Experimental Geography are the two closest fields that associate with the development of VGE from the perspective of geography. This paper discusses the background of VGE, introduces its research progress, and addresses key issues of VGE research and the significance for geography research from Experimental Geography and Virtual Geography. VGE can be an extended research object for the research of Virtual Geography and enrich the contents of future geography, while VGE can also be an extended research method for Experimental Geography that geographers can operate virtual geographic experiments based on VGE platforms.

  9. General uncertainty.

    PubMed

    Moore, Alison

    Many district general hospitals are likely to lose services, and some may close, as a result of the pressure to centralise specialist services, improve patient outcomes and cope with funding cuts. Nurses are increasingly willing to support intelligent reconfiguration if it will improve patient care, but changes in acute services have to be supported by improvements in the community.

  10. Generalized Parabolas

    ERIC Educational Resources Information Center

    Joseph, Dan; Hartman, Gregory; Gibson, Caleb

    2011-01-01

    In this article we explore the consequences of modifying the common definition of a parabola by considering the locus of all points equidistant from a focus and (not necessarily linear) directrix. The resulting derived curves, which we call "generalized parabolas," are often quite beautiful and possess many interesting properties. We show that…

  11. Generalized transduction.

    PubMed

    Thierauf, Anne; Perez, Gerardo; Maloy, And Stanley

    2009-01-01

    Transduction is the process in which bacterial DNA is transferred from one bacterial cell to another by means of a phage particle. There are two types of transduction, generalized transduction and specialized transduction. In this chapter two of the best-studied systems - Escherichia coli-phage P1, and Salmonella enterica-phage P22 - are discussed from theoretical and practical perspectives.

  12. The Contribution of Geographic Information Systems (GIS) to Geography Education and Secondary School Students' Attitudes Related to GIS

    ERIC Educational Resources Information Center

    Artvinli, Eyup

    2010-01-01

    The purpose of this study is to determine the place of Geographic Information Systems (GIS) in teaching geography, the general level of secondary school students' attitudes towards Geography Information Systems and whether this changes according to different variables. The population of the research consists of the students studying in Istanbul,…

  13. Geographic Differences in Social-Welfare Oriented Institutional Care for People with Disabilities in Taiwan, 2002-2009

    ERIC Educational Resources Information Center

    Lin, Lan-Ping; Hsu, Shang-Wei; Kuo, Fang-Yu; Lin, Jin-Ding

    2013-01-01

    The present paper aims to provide information of long-term trend of distribution and utilization of institutional care resource for people with disabilities by different geographic areas in Taiwan. Data were analyzed using governmental reported general population by administrative area, population of persons with disabilities, and the profile of…

  14. Interactions among climate and soil properties influence current and future geographic distribution of an invasive grass in the Chihuahuan Desert

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background/Question/Methods: Lehmann lovegrass (Eragrostis lehmanniana) is an invasive exotic perennial grass throughout the Sonoran Desert. However, in the neighboring Chihuahuan Desert, this species is generally present in low abundance, although data on its geographic distribution are scarce. Our...

  15. Geographic variation in cowbird distribution, abundance, and parasitism

    USGS Publications Warehouse

    Morrison, M.L.; Hahn, D.C.; George, T. Luke; Dobkin, David S.

    2002-01-01

    We evaluated geographical patterns in the abundance and distribution of Brown-headed Cowbirds (Molothrus ater), and in the frequency of cowbird parasitism, across North America in relation to habitat fragmentation. We found no distinctive parasitism patterns at the national or even regional scales, but the species is most abundant in the Great Plains, the heart of their original range, and least common in the southeastern U.S. This situation is dynamic, because both the Brown-headed and two other cowbird species are actively expanding their ranges in the southern U.S. We focused almost entirely in this paper on the Brown-headed Cowbird, because it is the only endemic North American cowbird, its distribution is much wider, and it has been much more intensively studied. We determined that landscape is the most meaningful unit of scale for comparing cowbird parasitism patterns as, for example, in comparisons of northeastern and central hardwood forests within agricultural matrices, and suburbanized areas versus western coniferous forests. We concluded that cowbird parasitism patterns were broadly similar within all landscapes. Even comparisons between prominently dissimilar landscapes, such as hardwoods in agriculture and suburbia versus coniferous forest, display a striking similarity in the responses of cowbirds. Our review clearly indicated that proximity of feeding areas is the key factor influencing presence and parasitism patterns within the landscape. We considered intensity of landscape fragmentation from forest-dominated landscapes altered in a forest management context to fragmentation characterized by mixed suburbanization or agricultural development. Our review consistently identified an inverse relationship between extent of forest cover across the landscape and cowbird presence. Invariably, the variation seen in parasitism frequencies within a region was at least partially explained as a response to changes in forest cover. The most salient geographic

  16. Teaching Poverty with Geographic Visualization and Geographic Information Systems (GIS): A Case Study of East Buffalo and Food Access

    ERIC Educational Resources Information Center

    Gjesfjeld, Christopher D.; Jung, Jin-Kyu

    2014-01-01

    Although various methods have been used to teach about poverty in the social work classroom (e.g., quantitative, historical, and qualitative), the use of geographic visualization and geographic information systems (GIS) has become a relatively new method. In our analysis of food access on the East Side of Buffalo, New York, we demonstrate the…

  17. Geographic Mosaic of Plant Evolution: Extrafloral Nectary Variation Mediated by Ant and Herbivore Assemblages

    PubMed Central

    Nogueira, Anselmo; Rey, Pedro J.; Alcántara, Julio M.; Feitosa, Rodrigo M.; Lohmann, Lúcia G.

    2015-01-01

    Herbivory is an ecological process that is known to generate different patterns of selection on defensive plant traits across populations. Studies on this topic could greatly benefit from the general framework of the Geographic Mosaic Theory of Coevolution (GMT). Here, we hypothesize that herbivory represents a strong pressure for extrafloral nectary (EFN) bearing plants, with differences in herbivore and ant visitor assemblages leading to different evolutionary pressures among localities and ultimately to differences in EFN abundance and function. In this study, we investigate this hypothesis by analyzing 10 populations of Anemopaegma album (30 individuals per population) distributed through ca. 600 km of Neotropical savanna and covering most of the geographic range of this plant species. A common garden experiment revealed a phenotypic differentiation in EFN abundance, in which field and experimental plants showed a similar pattern of EFN variation among populations. We also did not find significant correlations between EFN traits and ant abundance, herbivory and plant performance across localities. Instead, a more complex pattern of ant–EFN variation, a geographic mosaic, emerged throughout the geographical range of A. album. We modeled the functional relationship between EFNs and ant traits across ant species and extended this phenotypic interface to characterize local situations of phenotypic matching and mismatching at the population level. Two distinct types of phenotypic matching emerged throughout populations: (1) a population with smaller ants (Crematogaster crinosa) matched with low abundance of EFNs; and (2) seven populations with bigger ants (Camponotus species) matched with higher EFN abundances. Three matched populations showed the highest plant performance and narrower variance of EFN abundance, representing potential plant evolutionary hotspots. Cases of mismatched and matched populations with the lowest performance were associated with abundant

  18. [General psychotherapy].

    PubMed

    Vymetal, J

    2003-01-01

    Nowadays a theoretical psychotherapeutical thinking develops from the eclectic practice and uses particularly the research of the effective factors of the therapy. Best they can be characterized as differentiate, synthetic, integrative and exceeding other approaches. The development in question goes on with attempts of creating a general model of the psychotherapy that could be a basis for models of special psychotherapies. The aim of such a model is to describe all that is present as important factor for inducing a desirable change of a human in all psychotherapeutical approaches. Among general models we can mention the generic model of D. E. Orlinski and K. I. Howard, Grawe's cube (the author is K. Grawe) and the equation of the psychotherapy.

  19. Generalized Myoclonus

    PubMed Central

    McCullough, Louise D.

    2015-01-01

    Movement disorders have been reported as rare complications of stroke. The basal ganglia have been implicated in the pathophysiology of most post-stroke dyskinesias. We outline different types of post-stroke myoclonus and their possible pathophysiology. A middle-aged man developed generalized myoclonus after an ischemic stroke in the superior midbrain and subthalamic nuclei. Spontaneous resolution was seen by 72 hours. A lesion to the subthalamic nuclei disrupted the normal thalamic inhibition, which likely led to the involuntary movements seen in our patient. In this case, myoclonus was generalized, which, to the best of our knowledge, has not been reported in the literature as a direct consequence of focal stroke. PMID:25553226

  20. Temporal generalization.

    PubMed

    Church, R M; Gibbon, J

    1982-04-01

    Responses of 26 rats were reinforced following a signal of a certain duration, but not following signals of shorter or longer durations. This led to a positive temporal generalization gradient with a maximum at the reinforced duration in six experiments. Spacing of the nonreinforced signals did not influence the gradient, but the location of the maximum and breadth of the gradient increased with the duration of the reinforced signal. Reduction of reinforcement, either by partial reinforcement or reduction in the probability of a positive signal, led to a decrease in the height of the generalization gradient. There were large, reliable individual differences in the height and breadth of the generalization gradient. When the conditions of reinforcement were reversed (responses reinforced following all signals longer or shorter than a single nonreinforced duration), eight additional rats had a negative generalization gradient with a minimum at a signal duration shorter than the single nonreinforced duration. A scalar timing theory is described that provided a quantitative fit of the data. This theory involved a clock that times in linear units with an accurate mean and a negligible variance, a distribution of memory times that is normally distributed with an accurate mean and a scalar standard deviation, and a rule to respond if the clock is "close enough" to a sample of the memory time distribution. This decision is based on a ratio of the discrepancy between the clock time and the remembered time, to the remembered time. When this ratio is below a (variable) threshold, subjects respond. When three timing parameters--coefficient of variation of the memory time, the mean and the standard deviation of the threshold--were set at their median values, a theory with two free parameters accounted for 96% of the variance. The two parameters reflect the probability of attention to time and the probability of a response given inattention. These parameters were not influenced

  1. Geographic correlation of television pictures obtained from weather satellites

    NASA Technical Reports Server (NTRS)

    Bushuyev, A. V.

    1974-01-01

    The geographical control of satellite pictures, using the terminology of aerial photography, can be treated as the problem of analysis of a single picture with the objective of obtaining a ground contour map. Studies have shown the possibility and capability of the method of composing photographic maps from transformed television pictures. Optico-mechanical transformation solves the problem of geographical correlation for operational purposes. However, this technique does not compensate for electronic distortion, and accounts for earth sphericity only approximately. However, for certain purposes (studying ice drift), the maximum possible accuracy is required. Analytic geographical correlation methods using digital computers should be considered promising.

  2. New geographical approaches to control of some parasitic zoonoses.

    PubMed Central

    Mott, K. E.; Nuttall, I.; Desjeux, P.; Cattand, P.

    1995-01-01

    The advent of new technology for geographical representation and spatial analysis of databases from different sectors offers a new approach to planning and managing the control of tropical diseases. This article reviews the geographical and intersectoral aspects of the epidemiology and control of African trypanosomiasis, cutaneous and visceral leishmaniasis, Chagas disease, schistosomiasis, and foodborne trematode infections. The focal nature of their transmission, increasing recognition of the importance of animal reservoirs, and the need to understand environmental factors influencing their distribution are common to all these diseases. Geographical information systems (GIS) open a completely new perspective for intersectoral collaboration in adapting new technology to promote control of these diseases. PMID:7743598

  3. General energetics

    SciTech Connect

    Smil, V.

    1991-01-01

    This book is a comprehensive sourcebook for planetary management and strategies for sustainable development. Coupling biospheric and civilizational aspects, the book features thorough treatments of all critical energy storages, flows, and conversions. Measurements of energy and power densities and intensities are used throughout the book to provide an integrated framework of analysis for all segments of energetics from planetary and bioenergetics to the human energetics of hunting-gathering and agricultural societies through modern industrial civilization. Coverage also examines the environmental and socio-economic implication of the general patterns and trends of modern energy use.

  4. Geographic variation in speed of seed germination in central Oregon ponderosa pine ( pinus ponderosa' dougl. ex laws). Forest Service research paper

    SciTech Connect

    Weber, J.C.; Sorensen, F.C.

    1992-03-01

    Variation in speed of seed germination was investigated among ponderosa pine trees representing 225 locations in central Oregon. Results suggested that at least some of the geographic variation is related to the severity of summer drought. In general, germination speed was greater in locations with short, drought-limited growing seasons. Levels of geographic variation were highest in the region having the steepest precipitation gradients. Most of the variation occurred, however, within locations.

  5. [Geographical distribution of physicians in Chile].

    PubMed

    Goic, A

    1995-03-01

    In 1994, Chile had 15,451 active physicians (less than 70 years old) for a population of 14,027,344 with a ratio of 1 physician per 908 inhabitants, a satisfactory figure compared to other countries of similar socio-economical development. Ratios of 1:880 and 1:843 are projected for 1999 and 2004 respectively. The annual rate of physician's population growth (2.2%), that is superior to the general population's growth rate (1.6%), will increase to about 2.5% per annum in 2001 as a consequence of the creation of three new medical schools. However, the distribution of physicians along the country is unsatisfactory. While the capital (Metropolitan Region) has a ratio of 1 physician per 629 inhabitants, the figure for the Region of Maule is 1:2,113. Only two of ten regions, excepting the capital, have a ratio lower than 1:1,000. Sixty percent of physicians live in Santiago while only 40% of the general population does so, illustrating their high concentration. Median ratio in Chile, that better reflects the reality than the mean, is 1:1,280. The heterogeneous distribution of physicians in Chile is a sign of social inequity that must be corrected. In a free society a better physician distribution is achieved with economical and professional incentives given by health institutions.

  6. 47 CFR 27.15 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Geographic partitioning and spectrum disaggregation. 27.15 Section 27.15 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Applications and Licenses §...

  7. 47 CFR 27.15 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Geographic partitioning and spectrum disaggregation. 27.15 Section 27.15 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Applications and Licenses §...

  8. 47 CFR 27.15 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Geographic partitioning and spectrum disaggregation. 27.15 Section 27.15 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Applications and Licenses §...

  9. 47 CFR 27.15 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Geographic partitioning and spectrum disaggregation. 27.15 Section 27.15 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Applications and Licenses §...

  10. 47 CFR 27.15 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Geographic partitioning and spectrum disaggregation. 27.15 Section 27.15 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Applications and Licenses §...

  11. Order from noise: Toward a social theory of geographic information

    USGS Publications Warehouse

    Poore, B.S.; Chrisman, N.R.

    2006-01-01

    In the so-called Information Age, it is surprising that the concept of information is imprecisely defined and almost taken for granted. Historic and recent geographic information science (GIScience) literature relies on two conflicting metaphors, often espoused by the same author in adjacent paragraphs. The metaphor of invariance, derived from telecommunications engineering, defines information as a thing to be transported without loss through a conduit. Another metaphor, originating in the utopian movements of the 19th century, locates information within a hierarchy of refinement-a stopping place on the path to convert mere data into higher forms of knowledge and perhaps to wisdom. Both metaphors rely on long-forgotten debates outside geography and preclude us from seeing that there are important social and ethical concerns in the relationship between geographic information technologies and society. We examine the conflicts between competing metaphors and propose a social theory of geographic information. ?? 2006 by Association of American Geographers.

  12. Geographical distribution and temporal variation of rain acidity over China

    SciTech Connect

    Wen-Xing Wang; Yan-Bo Pang; Guo-An Ding

    1996-12-31

    In recent decade, large areas of acid rain have appeared in China. With the increasing emission of SO{sub 2} and NO{sub x} year by year, the acidity of precipitation has increased, and the acid rain area is expanding. Presently, the acid rain in China has become the third largest area of acid rain in the world, next to Europe and North America. The Chinese government took action against acid rain and planned a five-year National Acid Deposition Research Project. The space-time distribution and variation of rain acidity described in this paper is a part of this project. China is a large country. The area is almost equal to that of Europe. Its climate varies greatly and spans the tropics, subtropics, temperate and frigid zone. There is a varied topography including mountain, hilly country, desert and plain, on the other hand the distribution of anthropogenic sources are not even. All of the human and natural factors caused different chemical composition in different parts of China, the acidity of precipitation varies also. The acidity of the precipitation is the most important parameter in the acid rain research. In order to obtain the regional representative distribution of rain acidity, National Acidic Deposition Research Monitoring Network with 261 monitoring sites was established in 1992. This paper summarizes the rain acidity of 21355 precipitation samples, and gave the annual, seasonal, and the monthly pH contours. Results show that the acid rain area has expanded from the south during winter. Regional differences of monthly acid precipitation exists, generally, the rain acidity level is higher during summer and fall and lower during winter and spring in the northern provinces. The 9 opposite is the case in the southern provinces. The central areas are in a transitional situation. The geographical distribution and temporal variation of rain acidity are quite different from North America and Europe.

  13. Geographic and Operational Site Parameters List (GOSPL) for Hanford Assessments

    SciTech Connect

    Last, George V.; Nichols, William E.; Kincaid, Charles T.

    2006-06-01

    This data package was originally prepared to support a 2004 composite analysis (CA) of low-level waste disposal at the Hanford Site. The Technical Scope and Approach for the 2004 Composite Analysis of Low Level Waste Disposal at the Hanford Site (Kincaid et. al. 2004) identified the requirements for that analysis and served as the basis for initial preparation of this data package. Completion of the 2004 CA was later deferred, with the 2004 Annual Status Report for the Composite Analysis of Low-Level Waste Disposal in the Central Plateau at the Hanford Site (DOE 2005) indicating that a comprehensive update to the CA was in preparation and would be submitted in 2006. However, the U.S. Department of Energy (DOE) has recently decided to further defer the CA update and will use the cumulative assessment currently under preparation for the environmental impact statement (EIS) being prepared for tank closure and other site decisions as the updated CA. Submittal of the draft EIS is currently planned for FY 2008. This data package describes the facility-specific parameters (e.g. location, operational dates, etc.) used to numerically simulate contaminant flow and transport in large-scale Hanford assessments. Kincaid et al. (2004) indicated that the System Assessment Capability (SAC) (Kincaid et al. 2000; Bryce et al. 2002; Eslinger 2002a, 2002b) would be used to analyze over a thousand different waste sites. A master spreadsheet termed the Geographic and Operational Site Parameters List (GOSPL) was assembled to facilitate the generation of keyword input files containing general information on each waste site/facility, its operational/disposal history, and its environmental settings (past, current, and future). This report briefly describes each of the key data fields, including the source(s) of data, and provides the resulting inputs to be used for large-scale Hanford assessments.

  14. Geographic range did not confer resilience to extinction in terrestrial vertebrates at the end-Triassic crisis.

    PubMed

    Dunhill, Alexander M; Wills, Matthew A

    2015-01-01

    Rates of extinction vary greatly through geological time, with losses particularly concentrated in mass extinctions. Species duration at other times varies greatly, but the reasons for this are unclear. Geographical range correlates with lineage duration amongst marine invertebrates, but it is less clear how far this generality extends to other groups in other habitats. It is also unclear whether a wide geographical distribution makes groups more likely to survive mass extinctions. Here we test for extinction selectivity amongst terrestrial vertebrates across the end-Triassic event. We demonstrate that terrestrial vertebrate clades with larger geographical ranges were more resilient to extinction than those with smaller ranges throughout the Triassic and Jurassic. However, this relationship weakened with increasing proximity to the end-Triassic mass extinction, breaking down altogether across the event itself. We demonstrate that these findings are not a function of sampling biases; a perennial issue in studies of this kind. PMID:26261053

  15. The Relationship between Diet Breadth and Geographic Range Size in the Butterfly Subfamily Nymphalinae – A Study of Global Scale

    PubMed Central

    Slove, Jessica; Janz, Niklas

    2011-01-01

    The “oscillation hypothesis” has been proposed as a general explanation for the exceptional diversification of herbivorous insect species. The hypothesis states that speciation rates are elevated through repeated correlated changes – oscillations – in degree of host plant specificity and geographic range. The aim of this study is to test one of the predictions from the oscillation hypothesis: a positive correlation between diet breadth (number of host plants used) and geographic range size, using the globally distributed butterfly subfamily Nymphalinae. Data on diet breadth and global geographic range were collected for 182 Nymphalinae butterflies species and the size of the geographic range was measured using a GIS. We tested both diet breadth and geographic range size for phylogenetic signal to see if species are independent of each other with respect to these characters. As this test gave inconclusive results, data was analysed both using cross-species comparisons and taking phylogeny into account using generalised estimating equations as applied in the APE package in R. Irrespective of which method was used, we found a significant positive correlation between diet breadth and geographic range size. These results are consistent for two different measures of diet breadth and removal of outliers. We conclude that the global range sizes of Nymphalinae butterflies are correlated to diet breadth. That is, butterflies that feed on a large number of host plants tend to have larger geographic ranges than do butterflies that feed on fewer plants. These results lend support for an important step in the oscillation hypothesis of plant-driven diversification, in that it can provide the necessary fuel for future population fragmentation and speciation. PMID:21246054

  16. TIGER5---Extraction of geographic information from the TIGER system

    SciTech Connect

    Gryder, R.K.

    1992-03-01

    The need for geographic information in digital form is becoming apparent in many areas, including Emergency Response Planning and Management. The Bureau of Census recognized this need and developed an automated geographic data base, known as Topologically Integrated Geographic Encoding and Referencing (TIGER) System, to produce the geographic products for the 1990 census. The Bureau makes the information available to the public on CD-ROM disks. As distributed, the geographic information is not directly visible, and a program is needed to display the information in a graphic form. MapInfo is a commercially available program that has the capability to display maps and allows the user to perform certain geographic analyses. MapInfo runs on a variety of low-cost platforms that may be found in an average office environment, as well as on high-performance work stations. The TIGER5 program developed by the Emergency Management Information Systems (EMIS) project at Oak Ridge National Laboratory reads files directly from the Census Bureau TIGER/Line CD-ROM and creates MapInfo Exchange Format Files that can be directly imported into MapInfo. The standard default values for scaling parameters are used, and the resulting map is in the same coordinate system as the world and state maps distributed with MapInfo.

  17. a Conceptual Framework for Virtual Geographic Environments Knowledge Engineering

    NASA Astrophysics Data System (ADS)

    You, Lan; Lin, Hui

    2016-06-01

    VGE geographic knowledge refers to the abstract and repeatable geo-information which is related to the geo-science problem, geographical phenomena and geographical laws supported by VGE. That includes expert experiences, evolution rule, simulation processes and prediction results in VGE. This paper proposes a conceptual framework for VGE knowledge engineering in order to effectively manage and use geographic knowledge in VGE. Our approach relies on previous well established theories on knowledge engineering and VGE. The main contribution of this report is following: (1) The concepts of VGE knowledge and VGE knowledge engineering which are defined clearly; (2) features about VGE knowledge different with common knowledge; (3) geographic knowledge evolution process that help users rapidly acquire knowledge in VGE; and (4) a conceptual framework for VGE knowledge engineering providing the supporting methodologies system for building an intelligent VGE. This conceptual framework systematically describes the related VGE knowledge theories and key technologies. That will promote the rapid transformation from geodata to geographic knowledge, and furtherly reduce the gap between the data explosion and knowledge absence.

  18. Geographical range and speciation in fossil and living molluscs.

    PubMed Central

    Jablonski, David; Roy, Kaustuv

    2003-01-01

    The notion of a positive relation between geographical range and speciation rate or speciation probability may go back to Darwin, but a negative relation between these parameters is equally plausible. Here, we test these alternatives in fossil and living molluscan taxa. Late Cretaceous gastropod genera exhibit a strong negative relation between the geographical ranges of constituent species and speciation rate per species per million years; this result is robust to sampling biases against small-bodied taxa and is not attributable to phylogenetic effects. They also exhibit weak inverse or non-significant relations between geographical range and (i) the total number of species produced over the 18 million year timeframe, and (ii) the number of species in a single timeplane. Sister-group comparisons using extant molluscan species also show a non-significant relation between median geographical range and species richness of genera. These results support the view that the factors promoting broad geographical ranges also tend to damp speciation rates. They also demonstrate that a strong inverse relation between per-species speciation rate and geographical range need not be reflected in analyses conducted within a single timeplane, underscoring the inadequacy of treating net speciation as a proxy for raw per-taxon rates. PMID:12639320

  19. Population analysis of Vibrio parahaemolyticus originating from different geographical regions demonstrates a high genetic diversity

    PubMed Central

    2014-01-01

    Background Vibrio parahaemolyticus is frequently isolated from environmental and seafood samples and associated with gastroenteritis outbreakes in American, European, Asian and African countries. To distinguish between different lineages of V. parahaemolyticus various genotyping techniques have been used, incl. multilocus sequence typing (MLST). Even though some studies have already applied MLST analysis to characterize V. parahaemolyticus strain sets, these studies have been restricted to specific geographical areas (e.g. U.S. coast, Thailand and Peru), have focused exclusively on pandemic or non-pandemic pathogenic isolates or have been based on a limited strain number. Results To generate a global picture of V. parahaemolyticus genotype distribution, a collection of 130 environmental and seafood related V. parahaemolyticus isolates of different geographical origins (Sri Lanka, Ecuador, North Sea and Baltic Sea as well as German retail) was subjected to MLST analysis after modification of gyrB and recA PCRs. The V. parahaemolyticus population was composed of 82 unique Sequence Types (STs), of which 68 (82.9%) were new to the pubMLST database. After translating the in-frame nucleotide sequences into amino acid sequences, less diversity was detectable: a total of 31 different peptide Sequence Types (pSTs) with 19 (61.3%) new pSTs were generated from the analyzed isolates. Most STs did not show a global dissemination, but some were supra-regionally distributed and clusters of STs were dependent on geographical origin. On peptide level no general clustering of strains from specific geographical regions was observed, thereby the most common pSTs were found on all continents (Asia, South America and Europe) and rare pSTs were restricted to distinct countries or even geographical regions. One lineage of pSTs associated only with strains from North and Baltic Sea strains was identified. Conclusions Our study reveals a high genetic diversity in the analyzed V

  20. Deficiencies in the simulation of the geographic distribution of climate types by global climate models

    NASA Astrophysics Data System (ADS)

    Zhang, Xianliang; Yan, Xiaodong

    2016-05-01

    The performances of General Circulation Models (GCMs) when checked with conventional methods (i.e. correlation, bias, root-mean-square error) can only be evaluated for each variable individually. The geographic distribution of climate type in GCM simulations, which reflects the spatial attributes of models and is related closely to the terrestrial biosphere, has not yet been evaluated. Thus, whether the geographic distribution of climate types was well simulated by GCMs was evaluated in this study for nine GCMs. The results showed that large areas of climate zones classified by the GCMs were allocated incorrectly when compared to the basic climate zones established by observed data. The percentages of wrong areas covered approximately 30-50 % of the total land area for most models. In addition, the temporal shift in the distribution of climate zones according to the GCMs was found to be inaccurate. Not only were the locations of shifts poorly simulated, but also the areas of shift in climate zones. Overall, the geographic distribution of climate types was not simulated well by the GCMs, nor was the temporal shift in the distribution of climate zones. Thus, a new method on how to evaluate the simulated distribution of climate types for GCMs was provided in this study.

  1. Social Network Analysis and Qualitative Interviews for Assessing Geographic Characteristics of Tourism Business Networks.

    PubMed

    Kelman, Ilan; Luthe, Tobias; Wyss, Romano; Tørnblad, Silje H; Evers, Yvette; Curran, Marina Martin; Williams, Richard J; Berlow, Eric L

    2016-01-01

    This study integrates quantitative social network analysis (SNA) and qualitative interviews for understanding tourism business links in isolated communities through analysing spatial characteristics. Two case studies are used, the Surselva-Gotthard region in the Swiss Alps and Longyearbyen in the Arctic archipelago of Svalbard, to test the spatial characteristics of physical proximity, isolation, and smallness for understanding tourism business links. In the larger Surselva-Gotthard region, we found a strong relationship between geographic separation of the three communities on compartmentalization of the collaboration network. A small set of businesses played a central role in steering collaborative decisions for this community, while a group of structurally 'peripheral' actors were less influential. By contrast, the business community in Svalbard showed compartmentalization that was independent of geographic distance between actors. Within towns of similar size and governance scale, Svalbard is more compartmentalized, and those compartments are not driven by geographic separation of the collaboration clusters. This compartmentalization in Svalbard was reflected in a lower density of formal business collaboration ties compared to the communities of the Alps. We infer that the difference is due to Svalbard having higher cultural diversity and population turnover than the Alps communities. We propose that integrating quantitative network analysis from simple surveys with qualitative interviews targeted from the network results is an efficient general approach to identify regionally specific constraints and opportunities for effective governance.

  2. Social Network Analysis and Qualitative Interviews for Assessing Geographic Characteristics of Tourism Business Networks.

    PubMed

    Kelman, Ilan; Luthe, Tobias; Wyss, Romano; Tørnblad, Silje H; Evers, Yvette; Curran, Marina Martin; Williams, Richard J; Berlow, Eric L

    2016-01-01

    This study integrates quantitative social network analysis (SNA) and qualitative interviews for understanding tourism business links in isolated communities through analysing spatial characteristics. Two case studies are used, the Surselva-Gotthard region in the Swiss Alps and Longyearbyen in the Arctic archipelago of Svalbard, to test the spatial characteristics of physical proximity, isolation, and smallness for understanding tourism business links. In the larger Surselva-Gotthard region, we found a strong relationship between geographic separation of the three communities on compartmentalization of the collaboration network. A small set of businesses played a central role in steering collaborative decisions for this community, while a group of structurally 'peripheral' actors were less influential. By contrast, the business community in Svalbard showed compartmentalization that was independent of geographic distance between actors. Within towns of similar size and governance scale, Svalbard is more compartmentalized, and those compartments are not driven by geographic separation of the collaboration clusters. This compartmentalization in Svalbard was reflected in a lower density of formal business collaboration ties compared to the communities of the Alps. We infer that the difference is due to Svalbard having higher cultural diversity and population turnover than the Alps communities. We propose that integrating quantitative network analysis from simple surveys with qualitative interviews targeted from the network results is an efficient general approach to identify regionally specific constraints and opportunities for effective governance. PMID:27258007

  3. The Abduction of Geographic Information Science: Transporting Spatial Reasoning to the Realm of Purpose and Design

    NASA Astrophysics Data System (ADS)

    Couclelis, Helen

    People intuitively understand that function and purpose are critical parts of what human-configured entities are about, but these notions have proved difficult to capture formally. Even though most geographical landscapes bear traces of human purposes, visibly expressed in the spatial configurations meant to serve these purposes, the capability of GIS to represent means-ends relationships and to support associated reasoning and queries is currently quite limited. This is because spatial thinking as examined and codified in geographic information science is overwhelmingly of the descriptive, analytic kind that underlies traditional science, where notions of means and ends play a negligible role. This paper argues for the need to expand the reach of formalized spatial thinking to also encompass the normative, synthetic kinds of reasoning characterizing planning, engineering and the design sciences in general. Key elements in a more comprehensive approach to spatial thinking would be the inclusion of abductive modes of inference along with the deductive and inductive ones, and the development of an expanded geographic ontology that integrates analysis and synthesis, form and function, landscape and purpose, description and design.

  4. Because Muncie's Densities Are Not Manhattan's: Using Geographical Weighting in the EM Algorithm for Areal Interpolation

    PubMed Central

    Schroeder, Jonathan P.; Van Riper, David C.

    2014-01-01

    Areal interpolation transforms data for a variable of interest from a set of source zones to estimate the same variable's distribution over a set of target zones. One common practice has been to guide interpolation by using ancillary control zones that are related to the variable of interest's spatial distribution. This guidance typically involves using source zone data to estimate the density of the variable of interest within each control zone. This article introduces a novel approach to density estimation, the geographically weighted expectation-maximization (GWEM) algorithm, which combines features of two previously used techniques, the expectation-maximization (EM) algorithm and geographically weighted regression. The EM algorithm provides a framework for incorporating proper constraints on data distributions, and using geographical weighting allows estimated control-zone density ratios to vary spatially. We assess the accuracy of GWEM by applying it with land-use/land-cover ancillary data to population counts from a nationwide sample of 1980 United States census tract pairs. We find that GWEM generally is more accurate in this setting than several previously studied methods. Because target-density weighting (TDW)—using 1970 tract densities to guide interpolation—outperforms GWEM in many cases, we also consider two GWEM-TDW hybrid approaches, and find them to improve estimates substantially. PMID:24653524

  5. Social Network Analysis and Qualitative Interviews for Assessing Geographic Characteristics of Tourism Business Networks

    PubMed Central

    Luthe, Tobias; Wyss, Romano; Tørnblad, Silje H.; Evers, Yvette; Curran, Marina Martin; Williams, Richard J.; Berlow, Eric L.

    2016-01-01

    This study integrates quantitative social network analysis (SNA) and qualitative interviews for understanding tourism business links in isolated communities through analysing spatial characteristics. Two case studies are used, the Surselva-Gotthard region in the Swiss Alps and Longyearbyen in the Arctic archipelago of Svalbard, to test the spatial characteristics of physical proximity, isolation, and smallness for understanding tourism business links. In the larger Surselva-Gotthard region, we found a strong relationship between geographic separation of the three communities on compartmentalization of the collaboration network. A small set of businesses played a central role in steering collaborative decisions for this community, while a group of structurally ‘peripheral’ actors were less influential. By contrast, the business community in Svalbard showed compartmentalization that was independent of geographic distance between actors. Within towns of similar size and governance scale, Svalbard is more compartmentalized, and those compartments are not driven by geographic separation of the collaboration clusters. This compartmentalization in Svalbard was reflected in a lower density of formal business collaboration ties compared to the communities of the Alps. We infer that the difference is due to Svalbard having higher cultural diversity and population turnover than the Alps communities. We propose that integrating quantitative network analysis from simple surveys with qualitative interviews targeted from the network results is an efficient general approach to identify regionally specific constraints and opportunities for effective governance. PMID:27258007

  6. Assessment of Geographic Space Arrangement Based on the Amount of Information Contained In the Map Image

    NASA Astrophysics Data System (ADS)

    Eckes, Konrad

    2014-12-01

    In this paper an attempt was made to determine whether the amount of information, necessary to record a unit area of the geographic space, mapped on the large-scale map, may define the state of the arrangement of this space. The aim of this study was to make a comprehensive assessment of the geographical space in terms of its reasonable development. Intuition suggests that for two areas with similar functions - a picture of orderly and reasonably developed land and a disordered and chaotically developed land - one can record more concisely the image of the first than the latter. The work is an attempt to formulate an indicator that could characterize a state of the general arrangement of the geographical space and could serve as an objective assessment of such arrangement. The proposed statement was put to practical verification. At the introduction the numerical amount of information was specified, necessary to record unit area of large-scale cadastral maps, containing only the boundaries of the ownership. In the task the concept of the amount of information proposed by C. E. Shannon was used. For a typical map at scale 1:1000, to record the area of one square decimetre (i. e. one hectare in the terrain) 531 bits of information are necessary. For the area of fragmented fields of southeast Poland this number increased to 4980 bits. Basing on previous work of the author, quoted for comparison, the amount of information, necessary to record the identical unit of a typical city in the same coding method, is 23360 bits of information. In this case extensive infrastructure of the city recorded on the source layers has to be included. Later in the article, the amount of information necessary to record the same unit area of geographical space for the state of extreme disorder (chaos) and the state of the theoretical ideal arrangement was determined. The real determined values were much closer to the ideal in the ordered state than to the chaos. Subsequently, the amount of

  7. Geographic range size and extinction risk assessment in nomadic species.

    PubMed

    Runge, Claire A; Tulloch, Ayesha; Hammill, Edd; Possingham, Hugh P; Fuller, Richard A

    2015-06-01

    Geographic range size is often conceptualized as a fixed attribute of a species and treated as such for the purposes of quantification of extinction risk; species occupying smaller geographic ranges are assumed to have a higher risk of extinction, all else being equal. However many species are mobile, and their movements range from relatively predictable to-and-fro migrations to complex irregular movements shown by nomadic species. These movements can lead to substantial temporary expansion and contraction of geographic ranges, potentially to levels which may pose an extinction risk. By linking occurrence data with environmental conditions at the time of observations of nomadic species, we modeled the dynamic distributions of 43 arid-zone nomadic bird species across the Australian continent for each month over 11 years and calculated minimum range size and extent of fluctuation in geographic range size from these models. There was enormous variability in predicted spatial distribution over time; 10 species varied in estimated geographic range size by more than an order of magnitude, and 2 species varied by >2 orders of magnitude. During times of poor environmental conditions, several species not currently classified as globally threatened contracted their ranges to very small areas, despite their normally large geographic range size. This finding raises questions about the adequacy of conventional assessments of extinction risk based on static geographic range size (e.g., IUCN Red Listing). Climate change is predicted to affect the pattern of resource fluctuations across much of the southern hemisphere, where nomadism is the dominant form of animal movement, so it is critical we begin to understand the consequences of this for accurate threat assessment of nomadic species. Our approach provides a tool for discovering spatial dynamics in highly mobile species and can be used to unlock valuable information for improved extinction risk assessment and conservation

  8. Geographic range size and extinction risk assessment in nomadic species.

    PubMed

    Runge, Claire A; Tulloch, Ayesha; Hammill, Edd; Possingham, Hugh P; Fuller, Richard A

    2015-06-01

    Geographic range size is often conceptualized as a fixed attribute of a species and treated as such for the purposes of quantification of extinction risk; species occupying smaller geographic ranges are assumed to have a higher risk of extinction, all else being equal. However many species are mobile, and their movements range from relatively predictable to-and-fro migrations to complex irregular movements shown by nomadic species. These movements can lead to substantial temporary expansion and contraction of geographic ranges, potentially to levels which may pose an extinction risk. By linking occurrence data with environmental conditions at the time of observations of nomadic species, we modeled the dynamic distributions of 43 arid-zone nomadic bird species across the Australian continent for each month over 11 years and calculated minimum range size and extent of fluctuation in geographic range size from these models. There was enormous variability in predicted spatial distribution over time; 10 species varied in estimated geographic range size by more than an order of magnitude, and 2 species varied by >2 orders of magnitude. During times of poor environmental conditions, several species not currently classified as globally threatened contracted their ranges to very small areas, despite their normally large geographic range size. This finding raises questions about the adequacy of conventional assessments of extinction risk based on static geographic range size (e.g., IUCN Red Listing). Climate change is predicted to affect the pattern of resource fluctuations across much of the southern hemisphere, where nomadism is the dominant form of animal movement, so it is critical we begin to understand the consequences of this for accurate threat assessment of nomadic species. Our approach provides a tool for discovering spatial dynamics in highly mobile species and can be used to unlock valuable information for improved extinction risk assessment and conservation

  9. Forest management applications of Landsat data in a geographic information system

    NASA Technical Reports Server (NTRS)

    Maw, K. D.; Brass, J. A.

    1982-01-01

    The utility of land-cover data resulting from Landsat MSS classification can be greatly enhanced by use in combination with ancillary data. A demonstration forest management applications data base was constructed for Santa Cruz County, California, to demonstrate geographic information system applications of classified Landsat data. The data base contained detailed soils, digital terrain, land ownership, jurisdictional boundaries, fire events, and generalized land-use data, all registered to a UTM grid base. Applications models were developed from problems typical of fire management and reforestation planning.

  10. Measuring access to primary medical care: some examples of the use of geographical information systems.

    PubMed

    Parker, E B; Campbell, J L

    1998-06-01

    This paper explores the potential for geographical information system technology in defining some variables influencing the use of primary care medical services. Eighteen general practices in Scotland contributed to a study examining the accessibility of their services and their patients' use of the local Accident and Emergency Department. Geo-referencing of information was carried out through analysis of postcode data relating to practices and patients. This information was analyzed using ARC/INFO GIS software in conjunction with the ORACLE relational database and 1991 census information. The results demonstrate that GIS technology has an important role in defining and analyzing the use of health services by the population. PMID:10671022

  11. Micro-geographical differentiation in Northern Iberia revealed by Y-chromosomal DNA analysis.

    PubMed

    Brion, María; Quintans, Bea; Zarrabeitia, Maite; Gonzalez-Neira, Anna; Salas, Antonio; Lareu, Victoria; Tyler-Smith, Chris; Carracedo, Angel

    2004-03-31

    Y-chromosome diversity has been analyzed at a micro-geographical level, examining 10 binary polymorphisms and 7 short tandem repeats (STRs) in 443 samples belonging to 11 populations from two regions of Northern Spain, Galicia and Cantabria. Both regions, as a whole, cluster with other Iberian populations. However, some individual populations, particularly that from the Pas Valley in Cantabria, depart markedly from this general pattern, with higher genetic distances and reduced diversity. This unusual population is even more distinct than the Basques from their Iberian neighbors. Genetic drift in a small isolated population could explain this special behavior, and in addition to its anthropological interest, this finding has important forensic implications.

  12. Estimates of Gene Flow among Populations, Geographic Races, and Species in the Ipomopsis Aggregata Complex

    PubMed Central

    Wolf, P. G.; Soltis, P. S.

    1992-01-01

    Interpopulational gene flow within a species can reduce population differentiation due to genetic drift, whereas genetic exchange among taxa can impede speciation. We used allozyme data to estimate gene flow within and among geographic races and species of perennial herbs in the Ipomopsis aggregata complex (Polemoniaceae). Estimates of interpopulational gene flow within taxa from two methods (F statistics and private alleles) were correlated with one another. Gene flow among populations within each geographic race (subspecies) of I. aggregata was relatively high (Nm > ~1.0). Gene flow was also high among populations of I. arizonica and among four northern populations of I. tenuituba. However, gene flow was low (Nm < 1.0) for I. tenuituba when a population representing subsp. macrosiphon was included. This is consistent with previous findings that subsp. macrosiphon has had an independent origin and is reproductively, as well as geographically, isolated. A recently developed model, based on hierarchical F statistics, was employed to estimate genetic exchange among taxa. Gene flow estimates were generally high among races of I. aggregata (dNm(race) > 1.0) but were low among subspecies of I. tenuituba (dNm(race) < 1.0). Consistent with morphological evidence, estimates of interspecific gene flow were moderate between I. aggregata and I. tenuituba, which hybridize in several areas. However, contrary to morphological evidence, we estimated relatively high levels of interspecific gene flow involving I. arizonica. Our results suggest that I. arizonica has hybridized with other species without the transfer of morphological traits. In the I. aggregata complex, gene flow appears to be an important evolutionary force shaping geographic variation for allozymes within species, but is insufficient to prevent morphological divergence among taxa. PMID:1551582

  13. Testing the Finno-Ugrian Suicide Hypothesis: geographic variation of elderly suicide rates across Europe.

    PubMed

    Voracek, Martin; Marusic, Andrej

    2008-01-01

    The pattern of geographic variation in European suicide rates in the high-risk group of individuals aged 65 years and over was investigated, in order to provide a further test of the Finno-Ugrian Suicide Hypothesis, i.e. the assumption that genetic differences between populations may partially account for spatial differences seen in the suicide prevalence. National suicide rates (average of 1970-2002) of the elderly from 34 European countries were regressed on geographic position terms, i.e. capital cities' latitude and longitude, along with transformations (e.g. squared latitude) and interaction terms (e.g. latitude multiplied with longitude) of these, which statistically modeled various possible geographic gradients in the suicide rates. In these regression models, the strongest and statistically significant predictor of elderly suicide rates was an interaction term of squared latitude multiplied with longitude, indicating that suicide rates increased to the northeast. This accounted for 13.8% (total), 20.8% (males) and 11.6% (females) of the cross-national variance in elderly suicide rates. No further geographic position term accounted for a significant increment of further variance in suicide rates over and above this predictor. Controls for national quality of living conditions and alcohol consumption rates left these results essentially unchanged. Replicating previous evidence based on suicide rates of the general population, suicide rates of the elderly show a northeastern gradient across Europe. This J-shaped belt of high-suicide-rate countries spans from Central Europe (Austria, Hungary and Slovenia) to Northeastern Europe (Finland and the Baltic countries). There are early historical and genetic communalities among the populations inhabiting this area, but, in terms of culture, recent history, political systems and socioeconomic factors, there is great diversity between these countries. The current findings thus add to cumulated empirical evidence

  14. The effect of geographical indices on left ventricular structure in healthy Han Chinese population

    NASA Astrophysics Data System (ADS)

    Cen, Minyi; Ge, Miao; Liu, Yonglin; Wang, Congxia; Yang, Shaofang

    2016-07-01

    The left ventricular posterior wall thickness (LVPWT) and interventricular septum thickness (IVST) are generally regarded as the functional parts of the left ventricular (LV) structure. This paper aims to examine the effects of geographical indices on healthy Han adults' LV structural indices and to offer a scientific basis for developing a unified standard for the reference values of adults' LV structural indices in China. Fifteen terrain, climate, and soil indices were examined as geographical explanatory variables. Statistical analysis was performed using correlation analysis. Moreover, a back propagation neural network (BPNN) and a support vector regression (SVR) were applied to developing models to predict the values of two indices. After the prediction models were built, distribution maps were produced. The results show that LV structural indices are characteristically associated with latitude, longitude, altitude, average temperature, average wind velocity, topsoil sand fraction, topsoil silt fraction, topsoil organic carbon, and topsoil sodicity. The model test analyses show the BPNN model possesses better simulative and predictive ability in comparison with the SVR model. The distribution maps of the LV structural indices show that, in China, the values are higher in the west and lower in the east. These results demonstrate that the reference values of the adults' LV structural indices will be different affected by different geographical environment. The reference values of LV structural indices in one region can be calculated by setting up a BPNN, which showed better applicability in this study. The distribution of the reference values of the LV structural indices can be seen clearly on the geographical distribution map.

  15. Geodata Modeling and Query in Geographic Information Systems

    NASA Technical Reports Server (NTRS)

    Adam, Nabil

    1996-01-01

    Geographic information systems (GIS) deal with collecting, modeling, man- aging, analyzing, and integrating spatial (locational) and non-spatial (attribute) data required for geographic applications. Examples of spatial data are digital maps, administrative boundaries, road networks, and those of non-spatial data are census counts, land elevations and soil characteristics. GIS shares common areas with a number of other disciplines such as computer- aided design, computer cartography, database management, and remote sensing. None of these disciplines however, can by themselves fully meet the requirements of a GIS application. Examples of such requirements include: the ability to use locational data to produce high quality plots, perform complex operations such as network analysis, enable spatial searching and overlay operations, support spatial analysis and modeling, and provide data management functions such as efficient storage, retrieval, and modification of large datasets; independence, integrity, and security of data; and concurrent access to multiple users. It is on the data management issues that we devote our discussions in this monograph. Traditionally, database management technology have been developed for business applications. Such applications require, among other things, capturing the data requirements of high-level business functions and developing machine- level implementations; supporting multiple views of data and yet providing integration that would minimize redundancy and maintain data integrity and security; providing a high-level language for data definition and manipulation; allowing concurrent access to multiple users; and processing user transactions in an efficient manner. The demands on database management systems have been for speed, reliability, efficiency, cost effectiveness, and user-friendliness. Significant progress have been made in all of these areas over the last two decades to the point that many generalized database platforms

  16. A preliminary geodetic data model for geographic information systems

    NASA Astrophysics Data System (ADS)

    Kelly, K. M.

    2009-12-01

    Our ability to gather and assimilate integrated data collections from multiple disciplines is important for earth system studies. Moreover, geosciences data collection has increased dramatically, with pervasive networks of observational stations on the ground, in the oceans, in the atmosphere and in space. Contemporary geodetic observations from several space and terrestrial technologies contribute to our knowledge of earth system processes and thus are a valuable source of high accuracy information for many global change studies. Assimilation of these geodetic observations and numerical models into models of weather, climate, oceans, hydrology, ice, and solid Earth processes is an important contribution geodesists can make to the earth science community. Clearly, the geodetic observations and models are fundamental to these contributions. ESRI wishes to provide leadership in the geodetic community to collaboratively build an open, freely available content specification that can be used by anyone to structure and manage geodetic data. This Geodetic Data Model will provide important context for all geographic information. The production of a task-specific geodetic data model involves several steps. The goal of the data model is to provide useful data structures and best practices for each step, making it easier for geodesists to organize their data and metadata in a way that will be useful in their data analyses and to their customers. Built on concepts from the successful Arc Marine data model, we introduce common geodetic data types and summarize the main thematic layers of the Geodetic Data Model. These provide a general framework for envisioning the core feature classes required to represent geodetic data in a geographic information system. Like Arc Marine, the framework is generic to allow users to build workflow or product specific geodetic data models tailored to the specific task(s) at hand. This approach allows integration of the data with other existing

  17. Geographical epidemiology of prostate cancer in Great Britain.

    PubMed

    Jarup, Lars; Best, Nicky; Toledano, Mireille B; Wakefield, Jon; Elliott, Paul

    2002-02-10

    Prostate cancer incidence has increased during recent years, possibly linked to environmental exposures. Exposure to environmental carcinogens is unlikely to be evenly distributed geographically, which may give rise to variations in disease occurrence that is detectable in a spatial analysis. The aim of our study was to examine the spatial variation of prostate cancer in Great Britain at ages 45-64 years. Spatial variation was examined across electoral wards from 1975-1991. Poisson regression was used to examine regional, urbanisation and socioeconomic effects, while Bayesian mapping techniques were used to assess spatial variability. There was an indication of geographical differences in prostate cancer risk at a regional level, ranging from 0.83 (95% CI: 0.78-0.87) to 1.2 (95% CI: 1.1-1.3) across regions. There was significant heterogeneity in the risk across wards, although the range of relative risks was narrow. More detailed spatial analyses within 4 regions did not indicate any clear evidence of localised geographical clustering for prostate cancer. The absence of any marked geographical variability at a small-area scale argues against a geographically varying environmental factor operating strongly in the aetiology of prostate cancer. PMID:11807800

  18. 20. Raw Material for the Geographic Magazine. The mills of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. Raw Material for the Geographic Magazine. The mills of the Champion International Company which make paper on which the National Geographic Magazine is printed are located in Lawrence, Mass. This picture shows great piles of pulp-wood ready for conversion into paper for the The Geographic. Parts of these wood piles are more than 50 feet high. The cars shown in the picture are on a trestle 21 feet high. The Geographic magazines mailed in a single year, if laid side by side, would reach from Quito, Ecuador, across Colombia and Caribbean, thence across the United States and Canada, through the North Pole, and across Siberia, China, and Siam to Bangkok. It takes 33,000 miles of wrappers to mail one year's edition. It would require a bookshelf more than three and a half miles long to hold all the copies of this month's issue of The Geographic. (p.235.) - Champion-International Paper Company, West bank of Spicket River at Canal Street, Lawrence, Essex County, MA

  19. Geographical epidemiology of prostate cancer in Great Britain.

    PubMed

    Jarup, Lars; Best, Nicky; Toledano, Mireille B; Wakefield, Jon; Elliott, Paul

    2002-02-10

    Prostate cancer incidence has increased during recent years, possibly linked to environmental exposures. Exposure to environmental carcinogens is unlikely to be evenly distributed geographically, which may give rise to variations in disease occurrence that is detectable in a spatial analysis. The aim of our study was to examine the spatial variation of prostate cancer in Great Britain at ages 45-64 years. Spatial variation was examined across electoral wards from 1975-1991. Poisson regression was used to examine regional, urbanisation and socioeconomic effects, while Bayesian mapping techniques were used to assess spatial variability. There was an indication of geographical differences in prostate cancer risk at a regional level, ranging from 0.83 (95% CI: 0.78-0.87) to 1.2 (95% CI: 1.1-1.3) across regions. There was significant heterogeneity in the risk across wards, although the range of relative risks was narrow. More detailed spatial analyses within 4 regions did not indicate any clear evidence of localised geographical clustering for prostate cancer. The absence of any marked geographical variability at a small-area scale argues against a geographically varying environmental factor operating strongly in the aetiology of prostate cancer.

  20. Fast, Inclusive Searches for Geographic Names Using Digraphs

    USGS Publications Warehouse

    Donato, David I.

    2008-01-01

    An algorithm specifies how to quickly identify names that approximately match any specified name when searching a list or database of geographic names. Based on comparisons of the digraphs (ordered letter pairs) contained in geographic names, this algorithmic technique identifies approximately matching names by applying an artificial but useful measure of name similarity. A digraph index enables computer name searches that are carried out using this technique to be fast enough for deployment in a Web application. This technique, which is a member of the class of n-gram algorithms, is related to, but distinct from, the soundex, PHONIX, and metaphone phonetic algorithms. Despite this technique's tendency to return some counterintuitive approximate matches, it is an effective aid for fast, inclusive searches for geographic names when the exact name sought, or its correct spelling, is unknown.

  1. Secular trends and geographical variations in sex ratio at birth.

    PubMed

    Pavic, Dario

    2015-12-01

    Numerous studies have established the presence of secular trends and geographical variations in sex ratio at birth, albeit with mixed and often contradictory results. In addition, a multitude of environmental, social, economic, demographic and other factors has been proposed to influence the sex ratio at birth, thus complicating the interpretation of both secular trends and geographical variations. In this paper, the current state of knowledge on these issues is presented and critically assessed. Analyzing longer time series of sex ratio at birth with possible cycles and random components is given priority over establishing simple linear trends in the data. In analyzing the geographical variation in the sex ratio at birth, two different levels of analysis are distinguished (global and local), and two different sets of factors affecting the sex ratio at birth are proposed accordingly. Some key guidelines and future research directions are also proposed.

  2. Geographic Video 3d Data Model And Retrieval

    NASA Astrophysics Data System (ADS)

    Han, Z.; Cui, C.; Kong, Y.; Wu, H.

    2014-04-01

    Geographic video includes both spatial and temporal geographic features acquired through ground-based or non-ground-based cameras. With the popularity of video capture devices such as smartphones, the volume of user-generated geographic video clips has grown significantly and the trend of this growth is quickly accelerating. Such a massive and increasing volume poses a major challenge to efficient video management and query. Most of the today's video management and query techniques are based on signal level content extraction. They are not able to fully utilize the geographic information of the videos. This paper aimed to introduce a geographic video 3D data model based on spatial information. The main idea of the model is to utilize the location, trajectory and azimuth information acquired by sensors such as GPS receivers and 3D electronic compasses in conjunction with video contents. The raw spatial information is synthesized to point, line, polygon and solid according to the camcorder parameters such as focal length and angle of view. With the video segment and video frame, we defined the three categories geometry object using the geometry model of OGC Simple Features Specification for SQL. We can query video through computing the spatial relation between query objects and three categories geometry object such as VFLocation, VSTrajectory, VSFOView and VFFovCone etc. We designed the query methods using the structured query language (SQL) in detail. The experiment indicate that the model is a multiple objective, integration, loosely coupled, flexible and extensible data model for the management of geographic stereo video.

  3. Geographic variation in plant community structure of salt marshes: species, functional and phylogenetic perspectives.

    PubMed

    Guo, Hongyu; Chamberlain, Scott A; Elhaik, Eran; Jalli, Inder; Lynes, Alana-Rose; Marczak, Laurie; Sabath, Niv; Vargas, Amy; Więski, Kazimierz; Zelig, Emily M; Pennings, Steven C

    2015-01-01

    In general, community similarity is thought to decay with distance; however, this view may be complicated by the relative roles of different ecological processes at different geographical scales, and by the compositional perspective (e.g. species, functional group and phylogenetic lineage) used. Coastal salt marshes are widely distributed worldwide, but no studies have explicitly examined variation in salt marsh plant community composition across geographical scales, and from species, functional and phylogenetic perspectives. Based on studies in other ecosystems, we hypothesized that, in coastal salt marshes, community turnover would be more rapid at local versus larger geographical scales; and that community turnover patterns would diverge among compositional perspectives, with a greater distance decay at the species level than at the functional or phylogenetic levels. We tested these hypotheses in salt marshes of two regions: The southern Atlantic and Gulf Coasts of the United States. We examined the characteristics of plant community composition at each salt marsh site, how community similarity decayed with distance within individual salt marshes versus among sites in each region, and how community similarity differed among regions, using species, functional and phylogenetic perspectives. We found that results from the three compositional perspectives generally showed similar patterns: there was strong variation in community composition within individual salt marsh sites across elevation; in contrast, community similarity decayed with distance four to five orders of magnitude more slowly across sites within each region. Overall, community dissimilarity of salt marshes was lowest on the southern Atlantic Coast, intermediate on the Gulf Coast, and highest between the two regions. Our results indicated that local gradients are relatively more important than regional processes in structuring coastal salt marsh communities. Our results also suggested that in

  4. Role of satellite remote sensing in the geographic information economics in France

    NASA Astrophysics Data System (ADS)

    Denégre, Jean

    In national and international economics, geographic information plays a role which is generally acknowledged to be important but which is however, difficult to assess quantitatively, its applications being rather miscellaneous and indirect. Computer graphics and telecommunications increae that importance still more and justify many investments and research into new cartographic forms. As part of its responsibility for participating in the promotion of those developments, by taking into account needs expressed by public or private users, the National Council for Geographic Information (C.N.I.G.) has undertaken a general evaluation of the economic and social utility of geographic information in France. The study involves an estimation of the cost of production and research activities, which are probably about 0.1% of the Cross National Product—similar to many other countries. It also devised a method of estimating "cost/advantage" ratios applicable to these "intangible" benefits. Within that framework, remote sensing emphasizes particular aspects related both to the increase of economic performances in cartographic production and to the advent of new products and new ways of utilization. A review of some significant sectors shows effective earnings of about 10-20%, or even 50% or 100% of the costs, and these are doubtless much greater for the efficacy in the exploitation of products. Finally, many applications, entirely new result from extensions in various fields which would have been impossible without remote sensing: here the "cost advantage" ratio cannot even be compared with previous processes. Studies were undertaken in parallel for defining different types of products derived from satellite imagery, as well as those domains where development effort is required in order to make new advances.

  5. Geographic Variation in Plant Community Structure of Salt Marshes: Species, Functional and Phylogenetic Perspectives

    PubMed Central

    Guo, Hongyu; Chamberlain, Scott A.; Elhaik, Eran; Jalli, Inder; Lynes, Alana-Rose; Marczak, Laurie; Sabath, Niv; Vargas, Amy; Więski, Kazimierz; Zelig, Emily M.; Pennings, Steven C.

    2015-01-01

    In general, community similarity is thought to decay with distance; however, this view may be complicated by the relative roles of different ecological processes at different geographical scales, and by the compositional perspective (e.g. species, functional group and phylogenetic lineage) used. Coastal salt marshes are widely distributed worldwide, but no studies have explicitly examined variation in salt marsh plant community composition across geographical scales, and from species, functional and phylogenetic perspectives. Based on studies in other ecosystems, we hypothesized that, in coastal salt marshes, community turnover would be more rapid at local versus larger geographical scales; and that community turnover patterns would diverge among compositional perspectives, with a greater distance decay at the species level than at the functional or phylogenetic levels. We tested these hypotheses in salt marshes of two regions: The southern Atlantic and Gulf Coasts of the United States. We examined the characteristics of plant community composition at each salt marsh site, how community similarity decayed with distance within individual salt marshes versus among sites in each region, and how community similarity differed among regions, using species, functional and phylogenetic perspectives. We found that results from the three compositional perspectives generally showed similar patterns: there was strong variation in community composition within individual salt marsh sites across elevation; in contrast, community similarity decayed with distance four to five orders of magnitude more slowly across sites within each region. Overall, community dissimilarity of salt marshes was lowest on the southern Atlantic Coast, intermediate on the Gulf Coast, and highest between the two regions. Our results indicated that local gradients are relatively more important than regional processes in structuring coastal salt marsh communities. Our results also suggested that in

  6. Geographical access to community pharmacies in New Zealand.

    PubMed

    Norris, Pauline; Horsburgh, Simon; Sides, Gerald; Ram, Sanya; Fraser, John

    2014-09-01

    Geographic access to community pharmacies is an important aspect of access to appropriate medicines. This study aimed to explore changes in the number and location of pharmacies in New Zealand and determine whether some populations have poor geographical access to pharmacies. Pharmacy numbers in New Zealand have been declining since the mid-1980s, and, adjusted for population growth, there are now only half the number there was in 1965. While the urbanisation of pharmacies has been matched by loss of population in rural areas, the loss of pharmacies from smaller rural towns leaves many people with poor access to pharmacy services.

  7. GIS leads to more efficient route planning. [Geographic Information System

    SciTech Connect

    Not Available

    1993-04-26

    New computer approaches currently being developed by Argonne National Laboratory, Argonne, Ill., for the Gas Research Institute, Chicago, will make planning a pipeline route easier and more cost effective by combining a wide variety of geographical data for a specific area, according to GRI. The new approaches use currently available geographic information system (GIS) to store those data in digital form and present them in combinations of overlying layers. The paper describes some of the obstacles normally found along a proposed route; the options available within the GIS software; and the time and money saving advantages of the system.

  8. Paediatric Geographic Tongue: A Case Report, Review and Recent Updates

    PubMed Central

    Bhavana, Shivanand Bagalad; Deepak, Byathnal Suryakanth; Ashwini, Ramakrishna

    2016-01-01

    Geographic tongue is a benign recurrent condition of uncertain aetiology affecting the tongue characterized by loss of epithelium especially filiform papillae giving a characteristic appearance. The clinical presentation may vary from asymptomatic to painful and burning ulceration. The condition is commonly seen in adults but few cases are reported in children. A case of asymptomatic geographic tongue in three-year-old male child and literature review with new insight in aetiology is presented here. Management depends on the clinical condition and underlying aetiology. PMID:27042597

  9. Screening for lead exposure using a geographic information system

    SciTech Connect

    Wartenberg, D. )

    1992-12-01

    Screening programs for lead overexposure typically target high-risk populations by identifying regions with common risk markers (older housing, poverty, etc.). While more useful than untargeted screening programs, targeted programs are limited by the geographic resolution of the risk-factor information. A geographic information system can make screening programs more effective and more cost-efficient by mapping cases of overexposure, identifying high-incidence neighborhoods warranting screening, and validating risk-factor-based prediction rules. 5 refs., 5 figs., 2 tabs.

  10. [Differentiation of geographic biovariants of smallpox virus by PCR].

    PubMed

    Babkin, I V; Babkina, I N

    2010-01-01

    Comparative analysis of amino acid and nucleotides sequences of ORFs located in extended segments of the terminal variable regions in variola virus genome detected a promising locus for viral genotyping according to the geographic origin. This is ORF O1L of VARV. The primers were calculated for synthesis of this ORF fragment by PCR, which makes it possible to distinguish South America-Western Africa genotype from other VARV strains. Subsequent RFLP analysis reliably differentiated Asian strains from African strains (except Western Africa isolates). This method has been tested using 16 VARV strains from various geographic regions. The developed approach is simple, fast and reliable.

  11. Visual cues to geographical orientation during low-level flight

    NASA Technical Reports Server (NTRS)

    Battiste, Vernol; Delzell, Suzanne

    1991-01-01

    A field study of an operational Emergency Medical Service (EMS) unit was conducted to investigate the relationships among geographical orientation, pilot decision making, and workload in EMS flights. The map data collected during this study were compared to protocols gathered in the laboratory, where pilots viewed a simulated flight over different types of unfamiliar terrain and verbally identified the features utilized to maintain geographical orientation. The EMS pilot's questionnaire data were compared with data from non-EMS helicopter pilots with comparable flight experience.

  12. Uncontacted Waorani in the Yasuní Biosphere Reserve: Geographical Validation of the Zona Intangible Tagaeri Taromenane (ZITT).

    PubMed

    Pappalardo, Salvatore Eugenio; De Marchi, Massimo; Ferrarese, Francesco

    2013-01-01

    The Tagaeri Taromenane People are two indigenous groups belonging to the Waorani first nation living in voluntary isolation within the Napo region of the western Amazon rainforest. To protect their territory the Ecuadorean State has declared and geographically defined, by Decrees, the Zona Intangible Tagaeri Taromenane (ZITT). This zone is located within the UNESCO Yasuní Biosphere Reserve (1989), one of the most biodiverse areas in the world. Due to several hydrocarbon reserve exploitation projects running in the area and the advancing of a large-scale deforestation front, the survival of these groups is presently at risk. The general aim was to validate the ZITT boundary using the geographical references included in the Decree 2187 (2007) by analyzing the geomorphological characteristics of the area. Remote sensing data such as Digital Elevation Models (DEM), Landsat imagery, topographic cartography of IGM-Ecuador, and fieldwork geographical data have been integrated and processed by Geographical Information System (GIS). The ZITT presents two levels of geographic inconsistencies. The first dimension is about the serious cartographical weaknesses in the perimeter delimitation related to the impossibility of linking two rivers belonging to different basins while the second deals with the perimeter line not respecting the hydrographic network. The GIS analysis results clearly show that ZITT boundary is cartographically nonsense due to the impossibility of mapping out the perimeter. Furthermore, GIS analysis of anthropological data shows presence of Tagaeri Taromenane clans outside the ZITT perimeter, within oil production areas and in nearby farmer settlements, reflecting the limits of protection policies for non-contacted indigenous territory. The delimitation of the ZITT followed a traditional pattern of geometric boundary not taking into account the nomadic characteristic of Tagaeri Taromenane: it is necessary to adopt geographical approaches to recognize the

  13. Uncontacted Waorani in the Yasuní Biosphere Reserve: Geographical Validation of the Zona Intangible Tagaeri Taromenane (ZITT)

    PubMed Central

    Pappalardo, Salvatore Eugenio; De Marchi, Massimo; Ferrarese, Francesco

    2013-01-01

    The Tagaeri Taromenane People are two indigenous groups belonging to the Waorani first nation living in voluntary isolation within the Napo region of the western Amazon rainforest. To protect their territory the Ecuadorean State has declared and geographically defined, by Decrees, the Zona Intangible Tagaeri Taromenane (ZITT). This zone is located within the UNESCO Yasuní Biosphere Reserve (1989), one of the most biodiverse areas in the world. Due to several hydrocarbon reserve exploitation projects running in the area and the advancing of a large-scale deforestation front, the survival of these groups is presently at risk. The general aim was to validate the ZITT boundary using the geographical references included in the Decree 2187 (2007) by analyzing the geomorphological characteristics of the area. Remote sensing data such as Digital Elevation Models (DEM), Landsat imagery, topographic cartography of IGM-Ecuador, and fieldwork geographical data have been integrated and processed by Geographical Information System (GIS). The ZITT presents two levels of geographic inconsistencies. The first dimension is about the serious cartographical weaknesses in the perimeter delimitation related to the impossibility of linking two rivers belonging to different basins while the second deals with the perimeter line not respecting the hydrographic network. The GIS analysis results clearly show that ZITT boundary is cartographically nonsense due to the impossibility of mapping out the perimeter. Furthermore, GIS analysis of anthropological data shows presence of Tagaeri Taromenane clans outside the ZITT perimeter, within oil production areas and in nearby farmer settlements, reflecting the limits of protection policies for non-contacted indigenous territory. The delimitation of the ZITT followed a traditional pattern of geometric boundary not taking into account the nomadic characteristic of Tagaeri Taromenane: it is necessary to adopt geographical approaches to recognize the

  14. Uncontacted Waorani in the Yasuní Biosphere Reserve: Geographical Validation of the Zona Intangible Tagaeri Taromenane (ZITT).

    PubMed

    Pappalardo, Salvatore Eugenio; De Marchi, Massimo; Ferrarese, Francesco

    2013-01-01

    The Tagaeri Taromenane People are two indigenous groups belonging to the Waorani first nation living in voluntary isolation within the Napo region of the western Amazon rainforest. To protect their territory the Ecuadorean State has declared and geographically defined, by Decrees, the Zona Intangible Tagaeri Taromenane (ZITT). This zone is located within the UNESCO Yasuní Biosphere Reserve (1989), one of the most biodiverse areas in the world. Due to several hydrocarbon reserve exploitation projects running in the area and the advancing of a large-scale deforestation front, the survival of these groups is presently at risk. The general aim was to validate the ZITT boundary using the geographical references included in the Decree 2187 (2007) by analyzing the geomorphological characteristics of the area. Remote sensing data such as Digital Elevation Models (DEM), Landsat imagery, topographic cartography of IGM-Ecuador, and fieldwork geographical data have been integrated and processed by Geographical Information System (GIS). The ZITT presents two levels of geographic inconsistencies. The first dimension is about the serious cartographical weaknesses in the perimeter delimitation related to the impossibility of linking two rivers belonging to different basins while the second deals with the perimeter line not respecting the hydrographic network. The GIS analysis results clearly show that ZITT boundary is cartographically nonsense due to the impossibility of mapping out the perimeter. Furthermore, GIS analysis of anthropological data shows presence of Tagaeri Taromenane clans outside the ZITT perimeter, within oil production areas and in nearby farmer settlements, reflecting the limits of protection policies for non-contacted indigenous territory. The delimitation of the ZITT followed a traditional pattern of geometric boundary not taking into account the nomadic characteristic of Tagaeri Taromenane: it is necessary to adopt geographical approaches to recognize the

  15. Establishment of Homozygote Mutant Human Embryonic Stem Cells by Parthenogenesis.

    PubMed

    Epsztejn-Litman, Silvina; Cohen-Hadad, Yaara; Aharoni, Shira; Altarescu, Gheona; Renbaum, Paul; Levy-Lahad, Ephrat; Schonberger, Oshrat; Eldar-Geva, Talia; Zeligson, Sharon; Eiges, Rachel

    2015-01-01

    We report on the derivation of a diploid 46(XX) human embryonic stem cell (HESC) line that is homozygous for the common deletion associated with Spinal muscular atrophy type 1 (SMA) from a pathenogenetic embryo. By characterizing the methylation status of three different imprinted loci (MEST, SNRPN and H19), monitoring the expression of two parentally imprinted genes (SNRPN and H19) and carrying out genome-wide SNP analysis, we provide evidence that this cell line was established from the activation of a mutant oocyte by diploidization of the entire genome. Therefore, our SMA parthenogenetic HESC (pHESC) line provides a proof-of-principle for the establishment of diseased HESC lines without the need for gene manipulation. As mutant oocytes are easily obtained and readily available during preimplantation genetic diagnosis (PGD) cycles, this approach should provide a powerful tool for disease modelling and is especially advantageous since it can be used to induce large or complex mutations in HESCs, including gross DNA alterations and chromosomal rearrangements, which are otherwise hard to achieve. PMID:26473610

  16. THE WESTERN LAKE SUPERIOR COMPARATIVE WATERSHED FRAMEWORK: A FIELD TEST OF GEOGRAPHICALLY-DEPENDENT VS. THRESHOLD-BASED GEOGRAPHICALLY-INDEPENDENT CLASSIFICATION

    EPA Science Inventory

    Stratified random selection of watersheds allowed us to compare geographically-independent classification schemes based on watershed storage (wetland + lake area/watershed area) and forest fragmentation with a geographically-based classification scheme within the Northern Lakes a...

  17. Geographical threshold graphs with small-world and scale-free properties.

    PubMed

    Masuda, Naoki; Miwa, Hiroyoshi; Konno, Norio

    2005-03-01

    Many real networks are equipped with short diameters, high clustering, and power-law degree distributions. With preferential attachment and network growth, the model by Barabási and Albert simultaneously reproduces these properties, and geographical versions of growing networks have also been analyzed. However, nongrowing networks with intrinsic vertex weights often explain these features more plausibly, since not all networks are really growing. We propose a geographical nongrowing network model with vertex weights. Edges are assumed to form when a pair of vertices are spatially close and/or have large summed weights. Our model generalizes a variety of models as well as the original nongeographical counterpart, such as the unit disk graph, the Boolean model, and the gravity model, which appear in the contexts of percolation, wire communication, mechanical and solid physics, sociology, economy, and marketing. In appropriate configurations, our model produces small-world networks with power-law degree distributions. We also discuss the relation between geography, power laws in networks, and power laws in general quantities serving as vertex weights. PMID:15903494

  18. Using Open Geographic Data to Generate Natural Language Descriptions for Hydrological Sensor Networks

    PubMed Central

    Molina, Martin; Sanchez-Soriano, Javier; Corcho, Oscar

    2015-01-01

    Providing descriptions of isolated sensors and sensor networks in natural language, understandable by the general public, is useful to help users find relevant sensors and analyze sensor data. In this paper, we discuss the feasibility of using geographic knowledge from public databases available on the Web (such as OpenStreetMap, Geonames, or DBpedia) to automatically construct such descriptions. We present a general method that uses such information to generate sensor descriptions in natural language. The results of the evaluation of our method in a hydrologic national sensor network showed that this approach is feasible and capable of generating adequate sensor descriptions with a lower development effort compared to other approaches. In the paper we also analyze certain problems that we found in public databases (e.g., heterogeneity, non-standard use of labels, or rigid search methods) and their impact in the generation of sensor descriptions. PMID:26151211

  19. 47 CFR 27.904 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Geographic partitioning and spectrum disaggregation. 27.904 Section 27.904 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES 1670-1675 MHz Band § 27.904...

  20. 47 CFR 27.904 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Geographic partitioning and spectrum disaggregation. 27.904 Section 27.904 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES 1670-1675 MHz Band § 27.904...

  1. 47 CFR 27.1206 - Geographic Service Area.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Geographic Service Area. 27.1206 Section 27.1206 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Broadband Radio Service and Educational Broadband Service §...

  2. 47 CFR 27.805 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Geographic partitioning and spectrum disaggregation. 27.805 Section 27.805 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES 1.4 GHz Band § 27.805...

  3. 47 CFR 27.1206 - Geographic Service Area.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Geographic Service Area. 27.1206 Section 27.1206 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Broadband Radio Service and Educational Broadband Service §...

  4. 47 CFR 27.805 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Geographic partitioning and spectrum disaggregation. 27.805 Section 27.805 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES 1.4 GHz Band § 27.805...

  5. 47 CFR 27.805 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Geographic partitioning and spectrum disaggregation. 27.805 Section 27.805 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES 1.4 GHz Band § 27.805...

  6. 47 CFR 27.904 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Geographic partitioning and spectrum disaggregation. 27.904 Section 27.904 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES 1670-1675 MHz Band § 27.904...

  7. Teaching a Geographical Component in World History Curriculum

    ERIC Educational Resources Information Center

    Kachina, Olga A.

    2011-01-01

    This article is devoted to the topic of teaching a geographical component in World History curriculum in American public high schools. Despite the fact that the federal legislation entitled "No Child Left Behind" (2001) declared geography as a "core" academic subject, geography was the only subject dropped from federal funding.…

  8. Fungi Identify the Geographic Origin of Dust Samples

    PubMed Central

    Grantham, Neal S.; Reich, Brian J.; Pacifici, Krishna; Laber, Eric B.; Menninger, Holly L.; Henley, Jessica B.; Barberán, Albert; Leff, Jonathan W.; Fierer, Noah; Dunn, Robert R.

    2015-01-01

    There is a long history of archaeologists and forensic scientists using pollen found in a dust sample to identify its geographic origin or history. Such palynological approaches have important limitations as they require time-consuming identification of pollen grains, a priori knowledge of plant species distributions, and a sufficient diversity of pollen types to permit spatial or temporal identification. We demonstrate an alternative approach based on DNA sequencing analyses of the fungal diversity found in dust samples. Using nearly 1,000 dust samples collected from across the continental U.S., our analyses identify up to 40,000 fungal taxa from these samples, many of which exhibit a high degree of geographic endemism. We develop a statistical learning algorithm via discriminant analysis that exploits this geographic endemicity in the fungal diversity to correctly identify samples to within a few hundred kilometers of their geographic origin with high probability. In addition, our statistical approach provides a measure of certainty for each prediction, in contrast with current palynology methods that are almost always based on expert opinion and devoid of statistical inference. Fungal taxa found in dust samples can therefore be used to identify the origin of that dust and, more importantly, we can quantify our degree of certainty that a sample originated in a particular place. This work opens up a new approach to forensic biology that could be used by scientists to identify the origin of dust or soil samples found on objects, clothing, or archaeological artifacts. PMID:25875229

  9. Multidimensional Scaling: Review and Geographical Applications, Technical Paper No. 10.

    ERIC Educational Resources Information Center

    Golledge, R. G.; Rushton, Gerard

    The purpose of this monograph is to show that sufficient achievements in scaling applications have been made to justify serious study of scaling methodologies, particularly multidimensional scaling (MDS) as a tool for geographers. To be useful research, it was felt that the common methodological and technical problems that specialized researchers…

  10. Mental Maps and Ethnocentrism: Geographic Characterizations in the Past.

    ERIC Educational Resources Information Center

    Elliott, Harold M.

    1979-01-01

    Reexamines geographic thought regarding ethnocentrism as expressed in the writings including Ellen Churchill Semple, Hendrick Willem Van Loon, Ellsworth Huntington, Roswell C. Smith, J. Olney, Henry Thomas Buckle, Georg Friedrich Hegel, Johann Gottfried Von Herder, Charles de Montesquieu, Ibn Khaldun, and Hippocrates. (DB)

  11. Borderlands of the Southwest: An Exercise in Geographical History

    ERIC Educational Resources Information Center

    Thornton, Stephen J.

    2013-01-01

    In this article, the author argues that geography is more than a passive backdrop to time and events. Geographical perception is culturally mediated. He examines the case of the American Southwest and how its geography and historical heritage have been portrayed and how they might be otherwise if viewed through a different lens. (Contains 12…

  12. Using a Geographic Information System To Teach Economics.

    ERIC Educational Resources Information Center

    Peterson, Kenneth D., Jr.

    2000-01-01

    Focuses on the computer-based mapping tool called a geographic information system (GIS) that presents variations in economic indicators in thematic maps. Discusses thematic mapping benefits for students. Provides examples of thematic mapping in economics courses, addresses hardware and software requirements, and explains the process of creating…

  13. New Opportunities and Challenges: Geographic Information Systems in Libraries.

    ERIC Educational Resources Information Center

    McGlamery, Patrick; Lamont, Melissa

    1994-01-01

    Describes the Association of Research Libraries Geographic Information System (GIS) Literacy Project and the experiences of several libraries involved in electronic mapping. An in-depth description of the University of Connecticut's map library is provided. Sidebars include information about GIS business applications and sources of products…

  14. Electronic Mapping in Education: The Use of Geographic Information Systems.

    ERIC Educational Resources Information Center

    Sanders, Raymond L., Jr.; Kajs, Lawrence T.; Crawford, Caroline M.

    2002-01-01

    Discusses the use of electronic mapping and geographic information systems (GIS) in education. Highlights include GIS capabilities; learning environments; how GIS helps learners; examples of GIS in elementary and secondary education; GIS use by administration; and barriers to GIS implementation, including time, training, and cost. (LRW)

  15. Using Student Interviews for becoming a Reflective Geographer

    ERIC Educational Resources Information Center

    Adriansen, Hanne Kirstine; Madsen, Lene Møller

    2014-01-01

    This paper presents a case for interviewing students as an effective yet complex way to integrate reflexive practice into teaching and research. Even though many human geographers are accustomed to conducting qualitative interviews in various contexts, it is not straightforward to interview one's own students. This paper addresses three…

  16. Fungi identify the geographic origin of dust samples.

    PubMed

    Grantham, Neal S; Reich, Brian J; Pacifici, Krishna; Laber, Eric B; Menninger, Holly L; Henley, Jessica B; Barberán, Albert; Leff, Jonathan W; Fierer, Noah; Dunn, Robert R

    2015-01-01

    There is a long history of archaeologists and forensic scientists using pollen found in a dust sample to identify its geographic origin or history. Such palynological approaches have important limitations as they require time-consuming identification of pollen grains, a priori knowledge of plant species distributions, and a sufficient diversity of pollen types to permit spatial or temporal identification. We demonstrate an alternative approach based on DNA sequencing analyses of the fungal diversity found in dust samples. Using nearly 1,000 dust samples collected from across the continental U.S., our analyses identify up to 40,000 fungal taxa from these samples, many of which exhibit a high degree of geographic endemism. We develop a statistical learning algorithm via discriminant analysis that exploits this geographic endemicity in the fungal diversity to correctly identify samples to within a few hundred kilometers of their geographic origin with high probability. In addition, our statistical approach provides a measure of certainty for each prediction, in contrast with current palynology methods that are almost always based on expert opinion and devoid of statistical inference. Fungal taxa found in dust samples can therefore be used to identify the origin of that dust and, more importantly, we can quantify our degree of certainty that a sample originated in a particular place. This work opens up a new approach to forensic biology that could be used by scientists to identify the origin of dust or soil samples found on objects, clothing, or archaeological artifacts.

  17. Geographic migration of black and white families over four generations.

    PubMed

    Sharkey, Patrick

    2015-02-01

    This article analyzes patterns of geographic migration of black and white American families over four consecutive generations. The analysis is based on a unique set of questions in the Panel Study of Income Dynamics (PSID) asking respondents about the counties and states in which their parents and grandparents were raised. Using this information along with the extensive geographic information available in the PSID survey, the article tracks the geographic locations of four generations of family members and considers the ways in which families and places are linked together over the course of a family's history. The patterns documented in the article are consistent with much of the demographic literature on the Great Migration of black Americans out of the South, but they reveal new insights into patterns of black migration after the Great Migration. In the most recent generation, black Americans have remained in place to a degree that is unique relative to the previous generation and relative to whites of the same generation. This new geographic immobility is the most pronounced change in black Americans' migration patterns after the Great Migration, and it is a pattern that has implications for the demography of black migration as well as the literature on racial inequality.

  18. Geographical Data Conceptualization: An Approach to Student Understanding.

    ERIC Educational Resources Information Center

    Margulis, Harry L.

    Structuring geographical concepts so that they are intelligible to an uninitiated student is a recurrent problem in geography teaching. The subtle interrelationships between map distributions and analytical procedures are not intuitively clear, nor is it plainly evident that concise map analyses depend upon specific measures of distributions. This…

  19. Geographic Range Expansion for Rat Lungworm in North America

    PubMed Central

    Creecy, James P.; Lord, Wayne D.; Caire, William

    2015-01-01

    Using quantitative PCR analysis and DNA sequencing, we provide evidence for the presence of rat lungworm (Angiostrongylus cantonensis) in Oklahoma, USA, and identified a potentially novel rat host (Sigmodon hispidus). Our results indicate a geographic range expansion for this medically and ecologically relevant parasite in North America. PMID:26079818

  20. Television Weathercasts and Their Role in Geographic Education.

    ERIC Educational Resources Information Center

    Earl, Richard A.; Pasternack, Steve

    1991-01-01

    Urges increased geographic and meteorologic training for television weather reporters. Suggests using television weather reports to promote knowledge of place names and physical geography. Discusses a survey of television news departments in 48 states. Reports findings on the lengths of weather reports and the training of weather reporters. (DK)

  1. Geographical variation in mutualistic networks: similarity, turnover and partner fidelity

    PubMed Central

    Trøjelsgaard, Kristian; Jordano, Pedro; Carstensen, Daniel W.; Olesen, Jens M.

    2015-01-01

    Although species and their interactions in unison represent biodiversity and all the ecological and evolutionary processes associated with life, biotic interactions have, contrary to species, rarely been integrated into the concepts of spatial β-diversity. Here, we examine β-diversity of ecological networks by using pollination networks sampled across the Canary Islands. We show that adjacent and distant communities are more and less similar, respectively, in their composition of plants, pollinators and interactions than expected from random distributions. We further show that replacement of species is the major driver of interaction turnover and that this contribution increases with distance. Finally, we quantify that species-specific partner compositions (here called partner fidelity) deviate from random partner use, but vary as a result of ecological and geographical variables. In particular, breakdown of partner fidelity was facilitated by increasing geographical distance, changing abundances and changing linkage levels, but was not related to the geographical distribution of the species. This highlights the importance of space when comparing communities of interacting species and may stimulate a rethinking of the spatial interpretation of interaction networks. Moreover, geographical interaction dynamics and its causes are important in our efforts to anticipate effects of large-scale changes, such as anthropogenic disturbances. PMID:25632001

  2. Creating Local Field Trips: Seeing Geographical Principles through Empirical Eyes.

    ERIC Educational Resources Information Center

    Wheeler, James O.

    1985-01-01

    Discusses how instructors can design a local field trip for undergraduate students enrolled in an economic geography class. The purpose of the field trip is to help students observe and interpret familiar scenes in terms of geographical concepts such as central place theory, changing land use, and spatial competition. (RM)

  3. 2011 Asian Geographic Trend Report for GMAT[R] Examinees

    ERIC Educational Resources Information Center

    Graduate Management Admission Council, 2012

    2012-01-01

    The Asian Geographic Trend Report presents trends in the student pipeline for graduate management education. Examination of data collected from respondents taking the Graduate Management Admission Test[R] (GMAT[R]) during the 2007 and 2011 testing years (TY) and from the requested destination of their score reports forms the basis of this report.…

  4. 2011 World Geographic Trend Report for GMAT[R] Examinees

    ERIC Educational Resources Information Center

    Graduate Management Admission Council, 2012

    2012-01-01

    The World Geographic Trend Report presents trends in the student pipeline for graduate management education. Examination of data collected from respondents taking the Graduate Management Admission Test[R](GMAT[R]) during the 2007 and 2011 testing years (TY) and from the destination of their score reports forms the basis for this report. The GMAT…

  5. Self-Teaching Student's Manual for Geographic Information Systems (GIS).

    ERIC Educational Resources Information Center

    Cho, George

    This paper is a report of a project that was undertaken to produce a self-teaching manual for students wishing to acquire technical skills in Geographic Information Systems (GIS). Such skills are required in the analysis of locational data such as those found in aerial photographs, satellite images and digital maps. The self-teaching manual…

  6. Geographers as Planners: What Skills Does the Job Require.

    ERIC Educational Resources Information Center

    Stephens, David T.

    A survey of 524 planning agencies and consultants in the Midwest and Southwest was undertaken in 1976 to identify skills required for planning and to assess current capabilities in those skill areas. The major purpose of the survey was to aid geographic educators as they prepare students for careers in the planning profession. One part of the…

  7. Time and Practice: Learning to Become a Geographer

    ERIC Educational Resources Information Center

    Downs, Roger M.

    2014-01-01

    A goal of geography education is fostering geographic literacy for all and building significant expertise for some. How much time and practice do students need to become literate or expert in geography? There is not an answer to this question. Using two concepts from cognitive psychology--the ideas of ten thousand hours and deliberate…

  8. Geographical Scale Effects on the Analysis of Leptospirosis Determinants

    PubMed Central

    Gracie, Renata; Barcellos, Christovam; Magalhães, Mônica; Souza-Santos, Reinaldo; Barrocas, Paulo Rubens Guimarães

    2014-01-01

    Leptospirosis displays a great diversity of routes of exposure, reservoirs, etiologic agents, and clinical symptoms. It occurs almost worldwide but its pattern of transmission varies depending where it happens. Climate change may increase the number of cases, especially in developing countries, like Brazil. Spatial analysis studies of leptospirosis have highlighted the importance of socioeconomic and environmental context. Hence, the choice of the geographical scale and unit of analysis used in the studies is pivotal, because it restricts the indicators available for the analysis and may bias the results. In this study, we evaluated which environmental and socioeconomic factors, typically used to characterize the risks of leptospirosis transmission, are more relevant at different geographical scales (i.e., regional, municipal, and local). Geographic Information Systems were used for data analysis. Correlations between leptospirosis incidence and several socioeconomic and environmental indicators were calculated at different geographical scales. At the regional scale, the strongest correlations were observed between leptospirosis incidence and the amount of people living in slums, or the percent of the area densely urbanized. At the municipal scale, there were no significant correlations. At the local level, the percent of the area prone to flooding best correlated with leptospirosis incidence. PMID:25310536

  9. Using Children's Books to Teach Five Geographical Themes.

    ERIC Educational Resources Information Center

    Harthern, Alvis T.

    1992-01-01

    Contends that geographic literacy should not be taught in isolation but integrated with content. Recommends the use of children's literature to motivate students and enrich instruction. Describes how children's literature can be used to teach the 5 themes of geography and includes a list of 24 recommended books. (CFR)

  10. Geographic Information Systems: Empowering Kinds to Make a Difference.

    ERIC Educational Resources Information Center

    Michelsen, Michael W., Jr.

    1996-01-01

    Describes ArcView, a Geographic Information System (GIS) that enables K-12 classrooms to access electronic maps and information databases for specific communities. Presents actual applications of ArcView at an elementary school and a high school. Finds that students are using GIS technology to collect, analyze, and apply local data to real…

  11. Geographic Information Systems (GIS) as an Evaluation Tool.

    ERIC Educational Resources Information Center

    Renger, Ralph; Cimetta, Adriana; Pettygrove, Sydney; Rogan, Seumas

    2002-01-01

    Describes how Geographic Information Systems (GIS) can be used to help evaluators convey complex information simply through a spatial representation. Demonstrates how GIS can be used to plot change over time, including impact and outcome data gathered by primary data collection. (SLD)

  12. Towards Geographic Information Systems (GIS) Implementation: A Case Study

    ERIC Educational Resources Information Center

    Meaney, Miriam

    2006-01-01

    "Despite its central role in real-world geography, the Geographic Information System (GIS) has had little uptake to date in School Geography." (Wiegand, 2001) This statement can be accurately applied to the author's current school setting and was the focus of her and her colleagues' case study, commenced in 2004 and continued into 2005. The study…

  13. Learning the Local Political Landscape with Geographic Information Systems (GIS)

    ERIC Educational Resources Information Center

    Ball, William J.

    2009-01-01

    The focus of the paper is on the transformative effect on student learning and engagement that results from using contemporary Geographic Information Systems (GIS) tools and directed reflection to engage in spatial learning about the politics (literally) surrounding the student. I report on the pedagogical advantages of using spatial analysis…

  14. Case Study: Using Geographic Information Systems for Education Policy Analysis

    ERIC Educational Resources Information Center

    Mulvenon, Sean W.; Wang, Kening; McKenzie, Sarah; Airola, Denise

    2006-01-01

    Effective exploration of spatially referenced educational achievement data can help educational researchers and policy analysts accelerate interpretation of datasets to gain valuable insights. This paper illustrates the use of Geographic Information Systems (GIS) to analyze educational achievement gaps in Arkansas. It introduces the Geographic…

  15. Integrating Bayesian networks and geographic information systems: good practice examples.

    PubMed

    Johnson, Sandra; Low-Choy, Sama; Mengersen, Kerrie

    2012-07-01

    Bayesian networks (BNs) are becoming increasingly common in problems with spatial aspects. The degree of spatial involvement may range from spatial mapping of BN outputs based on nodes in the BN that explicitly involve geographic features, to integration of different networks based on geographic information. In these situations, it is useful to consider how geographic information systems (GISs) could be used to enhance the conceptualization, quantification, and prediction of BNs. Here, we discuss some techniques that may be used to integrate GIS and BN models, with reference to some recent literature which illustrate these approaches. We then reflect on 2 case studies based on our own experience. The first involves the integration of GIS and a BN to assess the scientific factors associated with initiation of Lyngbya majuscula, a cyanobacterium that occurs in coastal waterways around the world. The 2nd case study involves the use of GISs as an aid for eliciting spatially informed expert opinion and expressing this information as prior distributions for a Bayesian model and as input into a BN. Elicitator, the prototype software package we developed for achieving this, is also briefly described. Whereas the 1st case study demonstrates a GIS-data driven specification of conditional probability tables for BNs with complete geographical coverage for all the data layers involved, the 2nd illustrates a situation in which we do not have complete coverage and we are forced to extrapolate based on expert judgement.

  16. 47 CFR 76.984 - Geographically uniform rate structure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... operator with respect to the provision of cable service over its cable system in any geographic area in... system that is not subject to effective competition may not charge predatory prices to a multiple... that the discounted price is predatory, the cable system shall have the burden of showing that...

  17. Multimodal Geographic Information Systems: Adding Haptic and Auditory Display.

    ERIC Educational Resources Information Center

    Jeong, Wooseob; Gluck, Myke

    2003-01-01

    Investigated the feasibility of adding haptic and auditory displays to traditional visual geographic information systems (GISs). Explored differences in user performance, including task completion time and accuracy, and user satisfaction with a multimodal GIS which was implemented with a haptic display, auditory display, and combined display.…

  18. 47 CFR 76.984 - Geographically uniform rate structure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... operator with respect to the provision of cable service over its cable system in any geographic area in... system that is not subject to effective competition may not charge predatory prices to a multiple... that the discounted price is predatory, the cable system shall have the burden of showing that...

  19. Where and Why There? Spatial Thinking with Geographic Information Systems

    ERIC Educational Resources Information Center

    Milson, Andrew J.; Curtis, Mary D.

    2009-01-01

    The authors developed and implemented a project for high school geography students that modeled the processes in a site selection analysis using Geographic Information Systems (GIS). They sought to explore how spatial thinking could be fostered by using the MyWorld GIS software that was designed specifically for educational uses. The task posed…

  20. The Role of Standing Variation in Geographic Convergent Adaptation.

    PubMed

    Ralph, Peter L; Coop, Graham

    2015-10-01

    The extent to which populations experiencing shared selective pressures adapt through a shared genetic response is relevant to many questions in evolutionary biology. In this article, we explore how standing genetic variation contributes to convergent genetic responses in a geographically spread population. Geographically limited dispersal slows the spread of each selected allele, hence allowing other alleles to spread before any one comes to dominate the population. When selectively equivalent alleles meet, their progress is substantially slowed, dividing the species range into a random tessellation, which can be well understood by analogy to a Poisson process model of crystallization. In this framework, we derive the geographic scale over which an allele dominates and the proportion of adaptive alleles that arise from standing variation. Finally, we explore how negative pleiotropic effects of alleles can bias the subset of alleles that contribute to the species' adaptive response. We apply the results to the malaria-resistance glucose-6-phosphate dehydrogenase-deficiency alleles, where the large mutational target size makes it a likely candidate for adaptation from deleterious standing variation. Our results suggest that convergent adaptation may be common. Therefore, caution must be exercised when arguing that strongly geographically restricted alleles are the outcome of local adaptation. We close by discussing the implications of these results for ideas of species coherence and the nature of divergence between species. PMID:26656217

  1. Making Geographic Information Systems (GIS) Sustainable in Schools

    ERIC Educational Resources Information Center

    Dascombe, Brett

    2006-01-01

    Spatial technologies, particularly Geographic Information Systems (GIS), have become invaluable and persuasive tools in society today. These technologies have also made their way into classrooms around the world and Australian teachers are leaders in implementing GIS technology into their classrooms. There is still a way to go in order to make…

  2. "Latin" and "Anglo" America Geographic Regions Do Not Exist

    ERIC Educational Resources Information Center

    Bernardes DaSilva, Edmar; Kvasnak, Robert Neil

    2015-01-01

    The regional divisions termed as "Latin America" versus "Anglo-America" used by many geographers do not fully reflect the cultural and political trends in the world today. "Latin" is a term that was coined by the French Emperor Napoleon the III in order to justify Mexico's being ruled by Maximillian, and later picked…

  3. Epidemic variability in hierarchical geographical networks with human activity patterns.

    PubMed

    Zhao, Zhi-Dan; Liu, Ying; Tang, Ming

    2012-06-01

    Recently, some studies have revealed that non-Poissonian statistics of human behaviors stem from the hierarchical geographical network structure. On this view, we focus on epidemic spreading in the hierarchical geographical networks and study how two distinct contact patterns (i.e., homogeneous time delay (HOTD) and heterogeneous time delay (HETD) associated with geographical distance) influence the spreading speed and the variability of outbreaks. We find that, compared with HOTD and null model, correlations between time delay and network hierarchy in HETD remarkably slow down epidemic spreading and result in an upward cascading multi-modal phenomenon. Proportionately, the variability of outbreaks in HETD has the lower value, but several comparable peaks for a long time, which makes the long-term prediction of epidemic spreading hard. When a seed (i.e., the initial infected node) is from the high layers of networks, epidemic spreading is remarkably promoted. Interestingly, distinct trends of variabilities in two contact patterns emerge: high-layer seeds in HOTD result in the lower variabilities, the case of HETD is opposite. More importantly, the variabilities of high-layer seeds in HETD are much greater than that in HOTD, which implies the unpredictability of epidemic spreading in hierarchical geographical networks.

  4. Geographical range, heat tolerance and invasion success in aquatic species

    PubMed Central

    Bates, Amanda E.; McKelvie, Catherine M.; Sorte, Cascade J. B.; Morley, Simon A.; Jones, Nicholas A. R.; Mondon, Julie A.; Bird, Tomas J.; Quinn, Gerry

    2013-01-01

    Species with broader geographical ranges are expected to be ecological generalists, while species with higher heat tolerances may be relatively competitive at more extreme and increasing temperatures. Thus, both traits are expected to relate to increased survival during transport to new regions of the globe, and once there, establishment and spread. Here, we explore these expectations using datasets of latitudinal range breadth and heat tolerance in freshwater and marine invertebrates and fishes. After accounting for the latitude and hemisphere of each species’ native range, we find that species introduced to freshwater systems have broader geographical ranges in comparison to native species. Moreover, introduced species are more heat tolerant than related native species collected from the same habitats. We further test for differences in range breadth and heat tolerance in relation to invasion success by comparing species that have established geographically restricted versus extensive introduced distributions. We find that geographical range size is positively related to invasion success in freshwater species only. However, heat tolerance is implicated as a trait correlated to widespread occurrence of introduced populations in both freshwater and marine systems. Our results emphasize the importance of formal risk assessments before moving heat tolerant species to novel locations. PMID:24266040

  5. Geographically Isolated Wetlands: Why We Should Keep the Term

    EPA Science Inventory

    Use of the term "isolated wetlands" in the U.S. Supreme Court’s SWANCC decision created confusion, since it could imply functional isolation. In response, the term "geographically isolated wetlands" (GIWs) - wetlands surrounded by uplands - was introduced in 2003. A recent arti...

  6. 2. VIEW LOOKING EAST AT STEPS AND LAND WALL (GEOGRAPHIC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. VIEW LOOKING EAST AT STEPS AND LAND WALL (GEOGRAPHIC CENTER OF THE LOCK COMPLEX), FROM THE OHIO RIVER. - Ohio Slack Water Dams, Lock & Dam No. 4, East bank of Ohio River at mile point 18.6, along State Route 65, Ambridge, Beaver County, PA

  7. A Spatial User Similarity Measure for Geographic Recommender Systems

    NASA Astrophysics Data System (ADS)

    Matyas, Christian; Schlieder, Christoph

    Recommender systems solve an information filtering task. They suggest data objects that seem likely to be relevant to the user based upon previous choices that this user has made. A geographic recommender system recommends items from a library of georeferenced objects such as photographs of touristic sites. A widely-used approach to recommending consists in suggesting the most popular items within the user community. However, these approaches are not able to handle individual differences between users. We ask how to identify less popular geographic objects that are nevertheless of interest to a specific user. Our approach is based on user-based collaborative filtering in conjunction with an prototypical model of geographic places (heatmaps). We discuss four different measures of similarity between users that take into account the spatial semantic derived from the spatial behavior of a user community. We illustrate the method with a real-world use case: recommendations of georeferenced photographs from the public website Panoramio. The evaluation shows that our approach achieves a better recall and precision for the first ten items than recommendations based on the most popular geographic items.

  8. Geographic variation in the yellow-billed cuckoo

    USGS Publications Warehouse

    Banks, R.C.

    1988-01-01

    Populations of the Yellow-billed Cuckoo, Coocyzus americanus, west of the Rocky Mountains have average wing lengths slightly greater than those of eastern North America, but the difference is not sufficient for taxonomic recognition. There is no geographically oriented variation in bill size or color, and the species is best considered monotypic.

  9. Analysis and Assessment of Students' Competency to Explain Geographical Processes

    ERIC Educational Resources Information Center

    Dulama, Maria-Eliza; Alexandru, Diana-Elena

    2010-01-01

    In this study we seek to analyse the ability of students to explain, exemplify and outline geographical processes, as well as to assess their competencies by using an evaluation grid. Therefore, we tested two types of hypotheses. The first one regards the fact that it becomes more difficult for students to represent a previously learned…

  10. Knowledge Transfer between Two Geographically Distant Action Research Teams

    ERIC Educational Resources Information Center

    Desmarais, Lise; Parent, Robert; Leclerc, Louise; Raymond, Lysanne; MacKinnon, Scott; Vezina, Nicole

    2009-01-01

    Purpose: The objective of this study is to observe and document the transfer of a train the trainers program in knife sharpening and steeling. This knowledge transfer involved two groups of researchers: the experts and the learners. These groups are from geographically dispersed regions and evolve in distinct contexts by their language and…

  11. Teaching "with" Rather than "about" Geographic Information Systems

    ERIC Educational Resources Information Center

    Hammond, Thomas C.; Bodzin, Alec M.

    2009-01-01

    Both "teaching" and "teaching" with Geographic Information Systems (GIS) are "wicked problems," in the sense that they involve multiple variables that interact with one another. Effective teaching calls for both learning with understanding and transfer. The authors' own experience implementing a geography and geospatial inquiry project with middle…

  12. 47 CFR 69.707 - Geographic scope of petition.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) ACCESS CHARGES Pricing Flexibility § 69.707 Geographic scope of petition. (a) MSA. (1) A price cap LEC filing a petition for pricing flexibility in an MSA shall include data sufficient to support its petition... flexibility for two or more MSAs in a single petition, provided that it submits supporting data...

  13. 47 CFR 69.707 - Geographic scope of petition.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) ACCESS CHARGES Pricing Flexibility § 69.707 Geographic scope of petition. (a) MSA. (1) A price cap LEC filing a petition for pricing flexibility in an MSA shall include data sufficient to support its petition... flexibility for two or more MSAs in a single petition, provided that it submits supporting data...

  14. 47 CFR 69.707 - Geographic scope of petition.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) ACCESS CHARGES Pricing Flexibility § 69.707 Geographic scope of petition. (a) MSA. (1) A price cap LEC filing a petition for pricing flexibility in an MSA shall include data sufficient to support its petition... flexibility for two or more MSAs in a single petition, provided that it submits supporting data...

  15. 47 CFR 69.707 - Geographic scope of petition.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) ACCESS CHARGES Pricing Flexibility § 69.707 Geographic scope of petition. (a) MSA. (1) A price cap LEC filing a petition for pricing flexibility in an MSA shall include data sufficient to support its petition... flexibility for two or more MSAs in a single petition, provided that it submits supporting data...

  16. 47 CFR 69.707 - Geographic scope of petition.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) ACCESS CHARGES Pricing Flexibility § 69.707 Geographic scope of petition. (a) MSA. (1) A price cap LEC filing a petition for pricing flexibility in an MSA shall include data sufficient to support its petition... flexibility for two or more MSAs in a single petition, provided that it submits supporting data...

  17. 47 CFR 22.503 - Paging geographic area authorizations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Paging geographic area authorizations. 22.503 Section 22.503 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES.... 42 (Salt Lake City) 148-150, 152. 43 (San Francisco-Oakland-San Jose) 151, 162-165. 44 (Los...

  18. Web-Casting of Geographic Information Science Graduate Courses

    ERIC Educational Resources Information Center

    Onsrud, Harlan J.

    2005-01-01

    This case study from the University of Maine relates challenges, experiences and opportunities in broadcasting existing geographic information science graduate courses across the web using video streaming of class sessions in combination with web hosting of assignments, lecture outlines and reading materials. Technical, financial, logistical and…

  19. Applying Molecular Markers in Coriander Populations with Diverse Geographical Origins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Relationships between patterns of genetic diversity and geographical origins were studied in coriander by using amplified fragment length polymorphisms (AFLP) to survey coriander accessions. In 2005, 60 coriander accessions from 28 countries, from the USDA-ARS North Central Regional Plant Introduct...

  20. Geographic science for public and Tribal lands management

    USGS Publications Warehouse

    Torregrosa, Alicia; Hendley, James W. II

    2011-01-01

    There are more than 650 million acres of U.S. public and Tribal lands, most found west of the Mississippi River. Scientists with the U.S. Geological Survey's Western Geographic Science Center are working to increase the scientific information available for natural resource decision making, while continuing productive collaborations with Federal land managers, Tribal leaders, and local communities.

  1. 47 CFR 27.1206 - Geographic Service Area.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Geographic Service Area. 27.1206 Section 27.1206 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Broadband Radio Service and Educational Broadband Service §...

  2. 47 CFR 27.1206 - Geographic Service Area.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Geographic Service Area. 27.1206 Section 27.1206 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Broadband Radio Service and Educational Broadband Service §...

  3. 47 CFR 27.1206 - Geographic Service Area.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Geographic Service Area. 27.1206 Section 27.1206 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Broadband Radio Service and Educational Broadband Service §...

  4. Geographic Skills in the Social Studies, Grades K-6.

    ERIC Educational Resources Information Center

    Texas Education Agency, Austin. Div. of Curriculum Development.

    The booklet identifies 217 geography skills to be acquired by students in kindergarten through grade six. It is intended to help teachers in developing geographical strands and outcomes in the elementary social studies curriculum. Skills are presented for three grade levels: kindergarten through grade two, grades three and four, and grades five…

  5. Geographic information systems at the Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Goldberg, M.

    1982-01-01

    The basic functions of a Geographic Information System (GIS) and the different ways that a GIS may be implemented are described. It surveys that GIS software packages that are currently in operation at the Goddard Space Flight Center and discusses the types of applications for which they are best suited. Future plans for in-house GIS research and development are outlined.

  6. 42 CFR 412.316 - Geographic adjustment factors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 2 2011-10-01 2011-10-01 false Geographic adjustment factors. 412.316 Section 412.316 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Inpatient Hospital Capital Costs Basic Methodology for Determining the Federal Rate for...

  7. 42 CFR 412.316 - Geographic adjustment factors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Geographic adjustment factors. 412.316 Section 412.316 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Inpatient Hospital Capital Costs Basic Methodology for Determining the Federal Rate for...

  8. The Dictionary of Geography: The Complete Geographical Reference.

    ERIC Educational Resources Information Center

    O'Mahony, Kieran

    The object of study in geography is the earth, and more precisely, the earth as the home of man. Literacy, as applied to geography, involves a fresh new layer on the educational itinerary. It presumes that a person already has the ability to read and write and to communicate verbally. This dictionary of geographic literacy enhances this learning…

  9. Commitment Predictors: Long-Distance versus Geographically Close Relationships

    ERIC Educational Resources Information Center

    Pistole, M. Carole; Roberts, Amber; Mosko, Jonathan E.

    2010-01-01

    In this web-based study, the authors examined long-distance relationships (LDRs) and geographically close relationships (GCRs). Two hierarchical multiple regressions (N = 138) indicated that attachment predicted LDR and GCR commitment in Step 1. Final equations indicated that high satisfaction and investments predicted LDR commitment, whereas low…

  10. Geographically isolated wetlands: What we've learned since SWANCC

    EPA Science Inventory

    The 2001 SWANCC and 2006 Rapanos US Supreme Court decisions created a need for research on geographically isolated wetlands (GIWs). In 2003, a special issue on isolated wetlands was published in Wetlands. That issue contained fifteen papers that reviewed and summarized the lite...

  11. Ohio Geographers: Recent Research Themes. Volume Number 3: 1975.

    ERIC Educational Resources Information Center

    Harnapp, Vern, Ed.

    Eight professional geography research papers presented at the Geography Section of the Ohio Academy of Science annual 1975 meeting are provided. The papers examine various aspects of the environment, energy distribution, cultural and geographic change, and ethnic distribution. The titles of the eight papers are (1) Racial and Ethnic Redistribution…

  12. Keeping It Local: Geographic Patterns of University Attendance

    ERIC Educational Resources Information Center

    Edwards, Daniel

    2009-01-01

    The university attendance habits of Australians, in a geographic sense, are different from those in the United States, the United Kingdom and many other western countries. Australian university students are less likely to move between major cities to study. This paper finds that in addition to this, within a large metropolitan area, university…

  13. Geographical scale effects on the analysis of leptospirosis determinants.

    PubMed

    Gracie, Renata; Barcellos, Christovam; Magalhães, Mônica; Souza-Santos, Reinaldo; Barrocas, Paulo Rubens Guimarães

    2014-01-01

    Leptospirosis displays a great diversity of routes of exposure, reservoirs, etiologic agents, and clinical symptoms. It occurs almost worldwide but its pattern of transmission varies depending where it happens. Climate change may increase the number of cases, especially in developing countries, like Brazil. Spatial analysis studies of leptospirosis have highlighted the importance of socioeconomic and environmental context. Hence, the choice of the geographical scale and unit of analysis used in the studies is pivotal, because it restricts the indicators available for the analysis and may bias the results. In this study, we evaluated which environmental and socioeconomic factors, typically used to characterize the risks of leptospirosis transmission, are more relevant at different geographical scales (i.e., regional, municipal, and local). Geographic Information Systems were used for data analysis. Correlations between leptospirosis incidence and several socioeconomic and environmental indicators were calculated at different geographical scales. At the regional scale, the strongest correlations were observed between leptospirosis incidence and the amount of people living in slums, or the percent of the area densely urbanized. At the municipal scale, there were no significant correlations. At the local level, the percent of the area prone to flooding best correlated with leptospirosis incidence. PMID:25310536

  14. Lost in Space: Thinking Geographically about Pedagogy in English.

    ERIC Educational Resources Information Center

    Mahala, Daniel; Swilky, Jody

    Geographical thinking focuses on the extrinsic meanings of work in English, the meanings extracted from that work, intended or not, through mediating institutional forces, relationships, and modes of spatial organization. It considers how the effects of the work of English educators are mediated by the contiguity of their courses with other…

  15. The Social Sciences and Geographic Education: A Reader.

    ERIC Educational Resources Information Center

    Ball, John M., Ed.; And Others

    This book brings together articles by educators, geographers, social scientists, and those whose competence and interests cross two or more of these fields. Geography as a discipline has played an important part in social studies/social science education. These chapters are representative of current thinking on many facets of the interaction among…

  16. Making Space for the Citizen in Geographic Education

    ERIC Educational Resources Information Center

    Schmidt, Sandra J.

    2011-01-01

    This article argues that we need to reconsider the connection between citizenship and geography. Although geographic education purports to prepare citizens, the possibilities for this relationship have been addressed by few scholars. The study shows that citizenship is situated in places and students' actions as citizens reinscribe the meaning of…

  17. Students Investigate Local Communities with Geographic Information Systems (GIS).

    ERIC Educational Resources Information Center

    Carlstrom, Dick; Quinlan, Laurie A.

    1997-01-01

    Describes the use of Geographic Information Systems (GIS) in elementary and secondary school classrooms to analyze neighborhoods, cities, and regions. Discusses GIS software, databases, graphing data, and spatial analysis, and includes an example of a project for secondary school students investigating the local economy for summer jobs. (LRW)

  18. Geographic comparison of selected large-scale planetary surface features

    SciTech Connect

    Meszaros, S.P.

    1984-08-01

    Photographic and cartographic comparisons of geographic features on Mercury, the Moon, Earth, Mars, Ganymede, Callisto, Mimas, and Tethys are presented. Planetary structures caused by impacts, volcanism, tectonics, and other natural forces are included. Each feature is discussed individually and then those of similar origin are compared at the same scale.

  19. Fuel Cell Backup Power Geographical Visualization Map (Fact Sheet)

    SciTech Connect

    Not Available

    2012-12-01

    This NREL Hydrogen and Fuel Cell Technical Highlight describes a time-lapse geographical visualization map of early market use of fuel cells for telecommunications backup power. The map synthesizes data being analyzed by NREL's Technology Validation team for the U.S. Department of Energy (DOE) Fuel Cell Technologies Program with DOE's publicly available annual summaries of electric disturbance events.

  20. Enquiring into Primary Teachers' Geographical Knowledge

    ERIC Educational Resources Information Center

    Catling, Simon; Morley, Emma

    2013-01-01

    Subject knowledge is an important component of primary teachers' repertoire, though it has not been studied widely beyond their understandings of aspects of science and mathematics. Evaluations of the quality of teachers' geographical knowledge for teaching primary geography indicate a disparity between high quality teachers and less…