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Sample records for geographically divergent pythium

  1. Pythium insidiosum: An overview

    NARCIS (Netherlands)

    Gaastra, W.; Lipman, L.J.A.; De Cock, A.W.; Exel, T.K.; Pegge, R.B.; Scheurwater, J.; Vilela, R.; Mendoza, L.

    2010-01-01

    Pythium insidiosum is an oomycete pathogenic in mammals. The infection occurs mainly in tropical and subtropical areas, particularly in horses, dogs and humans. Infection is acquired through small wounds via contact with water that contains motile zoospores or other propagules (zoospores or hyphae).

  2. Ancient geographical barriers drive differentiation among Sonneratia caseolaris populations and recent divergence from S. lanceolata

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    Yuchen Yang

    2016-10-01

    Full Text Available Glacial vicariance is thought to influence population dynamics and speciation of many marine organisms. Mangroves, a plant group inhabiting intertidal zones, were also profoundly influenced by Pleistocene glaciations. In this study, we investigated phylogeographic patterns of a widespread mangrove species Sonneratia caseolaris and a narrowly distributed, closely related species S. lanceolata to infer their divergence histories and related it to historical geological events. We sequenced two chloroplast fragments and five nuclear genes for one population of S. lanceolata and 12 populations of S. caseolaris across the Indo-West Pacific (IWP region to evaluate genetic differentiation and divergence time among them. Phylogenetic analysis based on sequences of nuclear ribosomal internal transcribed spacer (nrITS and a nuclear gene rpl9 for all Sonneratia species indicate that S. lanceolata individuals are nested within S. caseolaris. We found strong genetic structure among geographic regions (South China Sea, the Indian Ocean and eastern Australia inhabited by S. caseolaris. We estimated that divergence between the Indo-Malesia and Australasia populations occurred 4.035 million years ago (MYA, prior to the onset of Pleistocene. BARRIERS analysis suggested that complex geographic features in the IWP region had largely shaped the phylogeographic patterns of S. caseolaris. Furthermore, haplotype analyses provided convincing evidence for secondary contact of the South China Sea (SCS and the Indian Ocean lineages at the Indo-Pacific boundary. Demographic history inference under isolation and migration (IM model detected substantial gene flow from the Sri Lanka populations to the populations in the Java Island. Moreover, multi-locus sequence analysis indicated that S. lanceolata was most closely related to the Indian Ocean populations of S. caseolaris and the divergence time between them was 2.057 MYA, coinciding with the onset of the Pleistocene

  3. Patterns of divergence across the geographic and genomic landscape of a butterfly hybrid zone associated with a climatic gradient

    Science.gov (United States)

    The process of speciation is impacted by the interaction between the genomic architecture of diverging lineages and the environmental context they occupy. Yet, while climate can have a significant impact on this interaction, its role in determining the patterns of geographic and genomic divergence i...

  4. Evaluating Genetic Association between Fusarium and Pythium ...

    African Journals Online (AJOL)

    Resistance to Fusarium root rot (Fusarium solani f.s.p phaseoli) has been reported in common bean (Phaseolus vulgaris L.) sources and is usually associated with Pythium root rot resistance. Pythium root rot (Pythium ultimum var ultimum) resistance is controlled by a single dominant gene, marked by a SCAR marker ...

  5. Phylogenetic heritability of geographic range size in haematophagous ectoparasites: time of divergence and variation among continents.

    Science.gov (United States)

    Krasnov, Boris R; Shenbrot, Georgy I; van der Mescht, Luther; Warburton, Elizabeth M; Khokhlova, Irina S

    2018-04-12

    To understand existence, patterns and mechanisms behind phylogenetic heritability in the geographic range size (GRS) of parasites, we measured phylogenetic signal (PS) in the sizes of both regional (within a region) and continental (within a continent) geographic ranges of fleas in five regions. We asked whether (a) GRS is phylogenetically heritable and (b) the manifestation of PS varies between regions. We also asked whether geographic variation in PS reflects the effects of the environment's spatiotemporal stability (e.g. glaciation disrupting geographic ranges) or is associated with time since divergence (accumulation differences among species over time). Support for the former hypothesis would be indicated by stronger PS in southern than in northern regions, whereas support for the latter hypothesis would be shown by stronger PS in regions with a large proportion of species belonging to the derived lineages than in regions with a large proportion of species belonging to the basal lineages. We detected significant PS in both regional and continental GRSs of fleas from Canada and in continental GRS of fleas from Mongolia. No PS was found in the GRS of fleas from Australia and Southern Africa. Venezuelan fleas demonstrated significant PS in regional GRS only. Local Indicators of Phylogenetic Association detected significant local positive autocorrelations of GRS in some clades even in regions in which PS has not been detected across the entire phylogeny. This was mainly characteristic of younger taxa.

  6. Geographic divergence in upper thermal limits across insect life stages: does behavior matter?

    Science.gov (United States)

    MacLean, Heidi J; Higgins, Jessica K; Buckley, Lauren B; Kingsolver, Joel G

    2016-05-01

    Insects with complex life cycles vary in size, mobility, and thermal ecology across life stages. We examine how differences in the capacity for thermoregulatory behavior influence geographic differences in physiological heat tolerance among egg and adult Colias butterflies. Colias adults exhibit differences in morphology (wing melanin and thoracic setal length) along spatial gradients, whereas eggs are morphologically indistinguishable. Here we compare Colias eriphyle eggs and adults from two elevations and Colias meadii from a high elevation. Hatching success and egg development time of C. eriphyle eggs did not differ significantly with the elevation of origin. Egg survival declined in response to heat-shock temperatures above 38-40 °C and egg development time was shortest at intermediate heat-shock temperatures of 33-38 °C. Laboratory experiments with adults showed survival in response to heat shock was significantly greater for Colias from higher than from lower elevation sites. Common-garden experiments at the low-elevation field site showed that C. meadii adults initiated heat-avoidance and over-heating behaviors significantly earlier in the day than C. eriphyle. Our study demonstrates the importance of examining thermal tolerances across life stages. Our findings are inconsistent with the hypothesis that thermoregulatory behavior inhibits the geographic divergence of physiological traits in mobile stages, and suggest that sessile stages may evolve similar heat tolerances in different environments due to microclimatic variability or evolutionary constraints.

  7. Geographic divergence and colour change in response to visual backgrounds and illumination intensity in bearded dragons.

    Science.gov (United States)

    Cadena, Viviana; Smith, Kathleen R; Endler, John A; Stuart-Fox, Devi

    2017-03-15

    Animals may improve camouflage by both dynamic colour change and local evolutionary adaptation of colour but we have little understanding of their relative importance in colour-changing species. We tested for differences in colour change in response to background colour and light intensity in two populations of central bearded dragon lizards ( Pogona vitticeps ) representing the extremes in body coloration and geographical range. We found that bearded dragons change colour in response to various backgrounds and that colour change is affected by illumination intensity. Within-individual colour change was similar in magnitude in the two populations but varied between backgrounds. However, at the endpoints of colour change, each population showed greater similarity to backgrounds that were representative of the local habitat compared with the other population, indicating local adaptation to visual backgrounds. Our results suggest that even in species that change colour, both phenotypic plasticity and geographic divergence of coloration may contribute to improved camouflage. © 2017. Published by The Company of Biologists Ltd.

  8. Geographic body size variation in the periodical cicadas Magicicada: implications for life cycle divergence and local adaptation.

    Science.gov (United States)

    Koyama, T; Ito, H; Kakishima, S; Yoshimura, J; Cooley, J R; Simon, C; Sota, T

    2015-06-01

    Seven species in three species groups (Decim, Cassini and Decula) of periodical cicadas (Magicicada) occupy a wide latitudinal range in the eastern United States. To clarify how adult body size, a key trait affecting fitness, varies geographically with climate conditions and life cycle, we analysed the relationships of population mean head width to geographic variables (latitude, longitude, altitude), habitat annual mean temperature (AMT), life cycle and species differences. Within species, body size was larger in females than males and decreased with increasing latitude (and decreasing habitat AMT), following the converse Bergmann's rule. For the pair of recently diverged 13- and 17-year species in each group, 13-year cicadas were equal in size or slightly smaller on average than their 17-year counterparts despite their shorter developmental time. This fact suggests that, under the same climatic conditions, 17-year cicadas have lowered growth rates compared to their 13-years counterparts, allowing 13-year cicadas with faster growth rates to achieve body sizes equivalent to those of their 17-year counterparts at the same locations. However, in the Decim group, which includes two 13-year species, the more southerly, anciently diverged 13-year species (Magicicada tredecim) was characterized by a larger body size than the other, more northerly 13- and 17-year species, suggesting that local adaptation in warmer habitats may ultimately lead to evolution of larger body sizes. Our results demonstrate how geographic clines in body size may be maintained in sister species possessing different life cycles. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  9. Foraging segregation and genetic divergence between geographically proximate colonies of a highly mobile seabird

    Science.gov (United States)

    Wiley, Anne E.; Welch, Andreanna J.; Ostrom, P.H.; James, Helen F.; Stricker, C.A.; Fleischer, R.C.; Gandhi, H.; Adams, J.; Ainley, D.G.; Duvall, F.; Holmes, N.; Hu, D.; Judge, S.; Penniman, J.; Swindle, K.A.

    2012-01-01

    Foraging segregation may play an important role in the maintenance of animal diversity, and is a proposed mechanism for promoting genetic divergence within seabird species. However, little information exists regarding its presence among seabird populations. We investigated genetic and foraging divergence between two colonies of endangered Hawaiian petrels (Pterodroma sandwichensis) nesting on the islands of Hawaii and Kauai using the mitochondrial Cytochrome b gene and carbon, nitrogen and hydrogen isotope values (?? 13C, ?? 15N and ??D, respectively) of feathers. Genetic analyses revealed strong differentiation between colonies on Hawaii and Kauai, with ?? ST = 0. 50 (p Feather ??D varied from -69 to 53???. This variation cannot be related solely to an isotopically homogeneous ocean water source or evaporative water loss. Instead, we propose the involvement of salt gland excretion. Our data demonstrate the presence of foraging segregation between proximately nesting seabird populations, despite high species mobility. This ecological diversity may facilitate population coexistence, and its preservation should be a focus of conservation strategies. ?? 2011 Springer-Verlag (outside the USA).

  10. Barcoding the butterflies of southern South America: Species delimitation efficacy, cryptic diversity and geographic patterns of divergence.

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    Pablo D Lavinia

    Full Text Available Because the tropical regions of America harbor the highest concentration of butterfly species, its fauna has attracted considerable attention. Much less is known about the butterflies of southern South America, particularly Argentina, where over 1,200 species occur. To advance understanding of this fauna, we assembled a DNA barcode reference library for 417 butterfly species of Argentina, focusing on the Atlantic Forest, a biodiversity hotspot. We tested the efficacy of this library for specimen identification, used it to assess the frequency of cryptic species, and examined geographic patterns of genetic variation, making this study the first large-scale genetic assessment of the butterflies of southern South America. The average sequence divergence to the nearest neighbor (i.e. minimum interspecific distance was 6.91%, ten times larger than the mean distance to the furthest conspecific (0.69%, with a clear barcode gap present in all but four of the species represented by two or more specimens. As a consequence, the DNA barcode library was extremely effective in the discrimination of these species, allowing a correct identification in more than 95% of the cases. Singletons (i.e. species represented by a single sequence were also distinguishable in the gene trees since they all had unique DNA barcodes, divergent from those of the closest non-conspecific. The clustering algorithms implemented recognized from 416 to 444 barcode clusters, suggesting that the actual diversity of butterflies in Argentina is 3%-9% higher than currently recognized. Furthermore, our survey added three new records of butterflies for the country (Eurema agave, Mithras hannelore, Melanis hillapana. In summary, this study not only supported the utility of DNA barcoding for the identification of the butterfly species of Argentina, but also highlighted several cases of both deep intraspecific and shallow interspecific divergence that should be studied in more detail.

  11. Barcoding the butterflies of southern South America: Species delimitation efficacy, cryptic diversity and geographic patterns of divergence.

    Science.gov (United States)

    Lavinia, Pablo D; Núñez Bustos, Ezequiel O; Kopuchian, Cecilia; Lijtmaer, Darío A; García, Natalia C; Hebert, Paul D N; Tubaro, Pablo L

    2017-01-01

    Because the tropical regions of America harbor the highest concentration of butterfly species, its fauna has attracted considerable attention. Much less is known about the butterflies of southern South America, particularly Argentina, where over 1,200 species occur. To advance understanding of this fauna, we assembled a DNA barcode reference library for 417 butterfly species of Argentina, focusing on the Atlantic Forest, a biodiversity hotspot. We tested the efficacy of this library for specimen identification, used it to assess the frequency of cryptic species, and examined geographic patterns of genetic variation, making this study the first large-scale genetic assessment of the butterflies of southern South America. The average sequence divergence to the nearest neighbor (i.e. minimum interspecific distance) was 6.91%, ten times larger than the mean distance to the furthest conspecific (0.69%), with a clear barcode gap present in all but four of the species represented by two or more specimens. As a consequence, the DNA barcode library was extremely effective in the discrimination of these species, allowing a correct identification in more than 95% of the cases. Singletons (i.e. species represented by a single sequence) were also distinguishable in the gene trees since they all had unique DNA barcodes, divergent from those of the closest non-conspecific. The clustering algorithms implemented recognized from 416 to 444 barcode clusters, suggesting that the actual diversity of butterflies in Argentina is 3%-9% higher than currently recognized. Furthermore, our survey added three new records of butterflies for the country (Eurema agave, Mithras hannelore, Melanis hillapana). In summary, this study not only supported the utility of DNA barcoding for the identification of the butterfly species of Argentina, but also highlighted several cases of both deep intraspecific and shallow interspecific divergence that should be studied in more detail.

  12. Allopatric speciation in ticks: genetic and reproductive divergence between geographic strains of Rhipicephalus (Boophilus microplus

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    Jongejan Frans

    2009-02-01

    Full Text Available Abstract Background The cattle tick, Rhipicephalus (Boophilus microplus, economically impact cattle industry in tropical and subtropical regions of the world. The morphological and genetic differences among R. microplus strains have been documented in the literature, suggesting that biogeographical and ecological separation may have resulted in boophilid ticks from America/Africa and those from Australia being different species. To test the hypothesis of the presence of different boophilid species, herein we performed a series of experiments to characterize the reproductive performance of crosses between R. microplus from Australia, Africa and America and the genetic diversity of strains from Australia, Asia, Africa and America. Results The results showed that the crosses between Australian and Argentinean or Mozambican strains of boophilid ticks are infertile while crosses between Argentinean and Mozambican strains are fertile. These results showed that tick strains from Africa (Mozambique and America (Argentina are the same species, while ticks from Australia may actually represent a separate species. The genetic analysis of mitochondrial 12S and 16S rDNA and microsatellite loci were not conclusive when taken separately, but provided evidence that Australian tick strains were genetically different from Asian, African and American strains. Conclusion The results reported herein support the hypothesis that at least two different species share the name R. microplus. These species could be redefined as R. microplus (Canestrini, 1887 (for American and African strains and probably the old R. australis Fuller, 1899 (for Australian strains, which needs to be redescribed. However, experiments with a larger number of tick strains from different geographic locations are needed to corroborate these results.

  13. Evaluation of Intego Solo (ethaboxam) for management of metalaxyl-resistant Pythium spp. in chickpea

    Science.gov (United States)

    Pythium damping-off and Pythium root rot, caused by numerous species of Pythium, can be a major limiting factor in the emergence and stand establishment of chickpea. Pythium spp. infect the germinating seed and seedling, often resulting in seed rot and subsequent damping-off in northern Idaho. Cur...

  14. Foot Rot of Ulluco Caused by Pythium aphanidermatum

    OpenAIRE

    Keisuke, TOMIOKA; Toyozo, SATO; Tateo, NAKANISHI; National Agricultural Research Center for Western Region; National Institute of Agrobiological Sciences; National Agricultural Research Center for Western Region

    2002-01-01

    Severe rot of stem bases caused by Pythium aphanidermatum was found on ulluco (Ullucus tuberosus) grown in Kagawa Prefecture, Japan, in September 1999. The name "foot rot of ulluco" is proposed for this new disease.

  15. Pathogenic and molecular characterisation of Pythium spp. inducing ...

    African Journals Online (AJOL)

    SARAH

    2016-08-31

    Aug 31, 2016 ... could be used to advice farmers not to include sorghum and peas when intercropping with beans, as they seem ... protein and the third most important source of ... (1988) was used to isolate the Pythium species from root.

  16. Selection and geographic isolation influence hummingbird speciation: genetic, acoustic and morphological divergence in the wedge-tailed sabrewing (Campylopterus curvipennis

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    Ornelas Juan

    2011-02-01

    Full Text Available Abstract Background Mesoamerica is one of the most threatened biodiversity hotspots in the world, yet we are far from understanding the geologic history and the processes driving population divergence and speciation for most endemic taxa. In species with highly differentiated populations selective and/or neutral factors can induce rapid changes to traits involved in mate choice, promoting reproductive isolation between allopatric populations that can eventually lead to speciation. We present the results of genetic differentiation, and explore drift and selection effects in promoting acoustic and morphological divergence among populations of Campylopterus curvipennis, a lekking hummingbird with an extraordinary vocal variability across Mesoamerica. Results Analyses of two mitochondrial genes and ten microsatellite loci genotyped for 160 individuals revealed the presence of three lineages with no contemporary gene flow: C. c. curvipennis, C. c. excellens, and C. c. pampa disjunctly distributed in the Sierra Madre Oriental, the Tuxtlas region and the Yucatan Peninsula, respectively. Sequence mtDNA and microsatellite data were congruent with two diversification events: an old vicariance event at the Isthmus of Tehuantepec (c. 1.4 Ma, and a more recent Pleistocene split, isolating populations in the Tuxtlas region. Hummingbirds of the excellens group were larger, and those of the pampa group had shorter bills, and lineages that have been isolated the longest shared fewer syllables and differed in spectral and temporal traits of a shared syllable. Coalescent simulations showed that fixation of song types has occurred faster than expected under neutrality but the null hypothesis that morphological divergence resulted from drift was not rejected. Conclusions Our phylogeographic analyses uncovered the presence of three Mesoamerican wedge-tailed sabrewing lineages, which diverged at different time scales. These results highlight the importance of the

  17. Phylogeography, genetic structure and population divergence time of cheetahs in Africa and Asia: evidence for long-term geographic isolates

    Science.gov (United States)

    Charruau, P; Fernandes, C; Orozco-terWengel, P; Peters, J; Hunter, L; Ziaie, H; Jourabchian, A; Jowkar, H; Schaller, G; Ostrowski, S; Vercammen, P; Grange, T; Schlötterer, C; Kotze, A; Geigl, E-M; Walzer, C; Burger, P A

    2011-01-01

    The cheetah (Acinonyx jubatus) has been described as a species with low levels of genetic variation. This has been suggested to be the consequence of a demographic bottleneck 10 000–12 000 years ago (ya) and also led to the assumption that only small genetic differences exist between the described subspecies. However, analysing mitochondrial DNA and microsatellites in cheetah samples from most of the historic range of the species we found relatively deep phylogeographic breaks between some of the investigated populations, and most of the methods assessed divergence time estimates predating the postulated bottleneck. Mitochondrial DNA monophyly and overall levels of genetic differentiation support the distinctiveness of Northern-East African cheetahs (Acinonyx jubatus soemmeringii). Moreover, combining archaeozoological and contemporary samples, we show that Asiatic cheetahs (Acinonyx jubatus venaticus) are unambiguously separated from African subspecies. Divergence time estimates from mitochondrial and nuclear data place the split between Asiatic and Southern African cheetahs (Acinonyx jubatus jubatus) at 32 000–67 000 ya using an average mammalian microsatellite mutation rate and at 4700–44 000 ya employing human microsatellite mutation rates. Cheetahs are vulnerable to extinction globally and critically endangered in their Asiatic range, where the last 70–110 individuals survive only in Iran. We demonstrate that these extant Iranian cheetahs are an autochthonous monophyletic population and the last representatives of the Asiatic subspecies A. j. venaticus. We advocate that conservation strategies should consider the uncovered independent evolutionary histories of Asiatic and African cheetahs, as well as among some African subspecies. This would facilitate the dual conservation priorities of maintaining locally adapted ecotypes and genetic diversity. PMID:21214655

  18. The geographic scale of diversification on islands: genetic and morphological divergence at a very small spatial scale in the Mascarene grey white-eye (Aves: Zosterops borbonicus

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    Thébaud Christophe

    2010-05-01

    Full Text Available Abstract Background Oceanic islands provide unique scenarios for studying the roles of geography and ecology in driving population divergence and speciation. Assessing the relative importance of selective and neutral factors in driving population divergence is central to understanding how such divergence may lead to speciation in small oceanic islands, where opportunities for gene flow and population mixing are potentially high. Here we report a case of genetic and morphological structure in the Mascarene grey white-eye (Zosterops borbonicus a species that shows a striking, geographically structured plumage polymorphism on the topographically and ecologically complex island of Réunion, yet is monotypic on the relatively uniform neighbouring island of Mauritius. Results Analysis of 276 AFLP loci in 197 individuals revealed prolonged independent evolution of Réunion and Mauritius populations, which is congruent with previous mtDNA assessments. Furthermore, populations on Réunion showed significant differentiation into three main genetic groups separating lowland from highland areas despite the small geographic distances involved. Genetic differentiation along the altitudinal gradient is consistent with morphometric analysis of fitness-related traits. Birds in the highlands were larger, yet had relatively smaller beaks than in the lowlands, suggesting the role of selection in shaping morphology and restricting gene flow along the gradient. No genetic differentiation between plumage morphs was detected in neutral markers, suggesting that plumage differences are of recent origin. Conclusions Our results suggest a dual role of vicariance and natural selection in differentiating populations of a passerine bird in an oceanic island at very small spatial scales. We propose a combination of past microallopatry driven by volcanic activity and selection-constrained dispersal along steep ecological gradients to explain the striking levels of population

  19. Population genetics of Southern Hemisphere tope shark (Galeorhinus galeus: Intercontinental divergence and constrained gene flow at different geographical scales.

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    Aletta E Bester-van der Merwe

    Full Text Available The tope shark (Galeorhinus galeus Linnaeus, 1758 is a temperate, coastal hound shark found in the Atlantic and Indo-Pacific oceans. In this study, the population structure of Galeorhinus galeus was determined across the entire Southern Hemisphere, where the species is heavily targeted by commercial fisheries, as well as locally, along the South African coastline. Analysis was conducted on a total of 185 samples using 19 microsatellite markers and a 671 bp fragment of the NADH dehydrogenase subunit 2 (ND2 gene. Across the Southern Hemisphere, three geographically distinct clades were recovered, including one from South America (Argentina, Chile, one from Africa (all the South African collections and an Australia-New Zealand clade. Nuclear data revealed significant population subdivisions (FST = 0.192 to 0.376, p<0.05 indicating limited gene flow for tope sharks across ocean basins. Marked population connectivity was however evident across the Indian Ocean based on Bayesian clustering analysis. More locally in South Africa, F-statistics and multivariate analysis supported moderate to high gene flow across the Atlantic/Indian Ocean boundary (FST = 0.035 to 0.044, p<0.05, with exception of samples from Struisbaai and Port Elizabeth which differed significantly from the rest. Discriminant and Bayesian clustering analysis indicated admixture in all sampling populations, decreasing from west to east, corroborating possible restriction to gene flow across regional oceanographic barriers. Mitochondrial sequence data recovered seven haplotypes (h = 0.216, π = 0.001 for South Africa, with one major haplotype shared by 87% of the individuals and at least one private haplotype for each sampling location except Port Elizabeth. As with many other coastal shark species with cosmopolitan distribution, this study confirms the lack of both historical dispersal and inter-oceanic gene flow while also implicating contemporary factors such as oceanic currents and

  20. Genetic differentiation among geographically isolated populations of Criollo cattle and their divergence from other Bos taurus breeds.

    Science.gov (United States)

    Russell, N D; Rios, J; Erosa, G; Remmenga, M D; Hawkins, D E

    2000-09-01

    The microsatellites HEL5, HEL9, INRA063, and BM2113 were used to analyze genetic similarities and differences of geographically isolated Criollo cattle herds in Mexico. Criollo cattle from five counties within the state of Chihuahua and one county from the state of Tamaulipas (n = 60) were sampled. The five counties in Chihuahua included Cerocahui (n = 14), Chinipas (n = 10), Guachochi (n = 15), Morelos (n = 30), and Temoris (n = 9). Samples of DNA were amplified by PCR and separated on a 7% polyacrylamide gel. Microsatellite size was established by comparison to M13mp18 DNA ladder and a documented set of four bovine controls. Allele frequencies and genotypic deviations from Hardy-Weinberg equilibrium were tested using the GENEPOP program. Eleven alleles were generated at HEL5 for the populations sampled (149 to 169 bp). Allele frequencies were greatest for the 163-bp allele in Criollo cattle from Cerocahui, Chinipas, Moralos, and Tamaulipas (0.23 to 0.5). Cattle from Guachochi had an allele frequency of 0.38 for the 151-bp allele, and cattle from Temoris had an allele frequency of 0.25 for the 149- and 167-bp alleles, with no 163-bp allele. Amplification with HEL9 produced 12 alleles (145, 149 to 169 bp) and showed common high-frequency alleles at 149, 157, and 159 bp for animals from all regions. The Chinipas population showed a moderate allele frequency at 145 bp; no other regions contained this allele. For INRA063 there were five alleles with 182 and 184 bp in low frequency. For BM2113 there were 10 alleles in the Criollo cattle (125 to 143 bp), with an equal distribution of frequencies for all alleles. In two regions, Guachochi and Morelos, genotypic frequencies deviated from Hardy-Weinberg equilibrium. Cattle from the Temoris region were genetically most distant from Criollo cattle of the other five regions.

  1. Probability Models Based on Soil Properties for Predicting Presence-Absence of Pythium in Soybean Roots.

    Science.gov (United States)

    Zitnick-Anderson, Kimberly K; Norland, Jack E; Del Río Mendoza, Luis E; Fortuna, Ann-Marie; Nelson, Berlin D

    2017-10-01

    Associations between soil properties and Pythium groups on soybean roots were investigated in 83 commercial soybean fields in North Dakota. A data set containing 2877 isolates of Pythium which included 26 known spp. and 1 unknown spp. and 13 soil properties from each field were analyzed. A Pearson correlation analysis was performed with all soil properties to observe any significant correlation between properties. Hierarchical clustering, indicator spp., and multi-response permutation procedures were used to identify groups of Pythium. Logistic regression analysis using stepwise selection was employed to calculate probability models for presence of groups based on soil properties. Three major Pythium groups were identified and three soil properties were associated with these groups. Group 1, characterized by P. ultimum, was associated with zinc levels; as zinc increased, the probability of group 1 being present increased (α = 0.05). Pythium group 2, characterized by Pythium kashmirense and an unknown Pythium sp., was associated with cation exchange capacity (CEC) (α < 0.05); as CEC increased, these spp. increased. Group 3, characterized by Pythium heterothallicum and Pythium irregulare, were associated with CEC and calcium carbonate exchange (CCE); as CCE increased and CEC decreased, these spp. increased (α = 0.05). The regression models may have value in predicting pathogenic Pythium spp. in soybean fields in North Dakota and adjacent states.

  2. Two pathogenic species of Pythium: P. aphanidermatum and P. diclinum from a wheat field

    OpenAIRE

    Al-Sheikh, Hashem

    2010-01-01

    During a survey of pathogenic and non-pathogenic Pythium spp. in different localities in Egypt, several isolates of Pythia were obtained and maintained on corn meal agar. Among these isolates, Pythium aphanidermatum and Pythium diclinum were obtained from rhizosphere of wheat plants grown in Dear Attia village, Minia, Egypt. Identification was made using morphological and molecular analyses. P. aphanidermatum and P. diclinum were able to cause reductions in emergence and adulating in wheat in...

  3. Finite Divergence

    DEFF Research Database (Denmark)

    Hansen, Michael Edberg; Pandya, P. K.; Chaochen, Zhou

    1995-01-01

    the framework of duration calculus. Axioms and proof rules are given. Patterns of occurrence of divergence are classified into dense divergence, accumulative divergence and discrete divergence by appropriate axioms. Induction rules are given for reasoning about discrete divergence...

  4. Pythium insidiosum colitis in a dog: treatment and clinical outcome

    OpenAIRE

    Fujimori, Mahyumi; Lopes, Erika Rondon; Lima, Samara Rosolem; Paula, Daphine Ariadne Jesus de; Almeida, Arleana do Bom Parto Ferreira de; Colodel, Edson Moleta; Pescador, Caroline Argenta; Néspoli, Pedro Eduardo Brandini; Nakazato, Luciano; Dutra, Valéria; Souza, Roberto Lopes de; Sousa, Valéria Régia Franco

    2016-01-01

    ABSTRACT: The aim of this report is to describe the clinical, pathological and imaging findings and treatment of colitis caused by Pythium insidiosum in a canine presenting haematochezia and progressive weight loss. Through imaging, a thickening of the transverse and descending colon was observed. Histopathological analysis of the large intestine fragment revealed the presence of hyphae, confirmed by immunohistochemistry and PCR as P. insidiosum. Antifungal treatment with itraconazole impleme...

  5. Zoosporogênese in vitro entre isolados do oomiceto Pythium insidiosum In vitro zoosporogenesis among oomycetes Pythium insidiosum isolates

    Directory of Open Access Journals (Sweden)

    Daniela Isabel Brayer Pereira

    2008-02-01

    Full Text Available Pythium insidiosum é um oomiceto aquático, responsável pela etiologia da pitiose, uma enfermidade crônica, observada freqüentemente em eqüinos. A produção de zoósporos móveis por este microrganismo se constitui no fator determinante da ocorrência da enfermidade. Este estudo avaliou a zoosporogênese e quantificou a produção de zoósporos de 32 amostras de Pythium insidiosum isoladas de eqüinos naturalmente infectados. Pythium insidiosum foi cultivado em meio Corn Meal Agar acrescido de fragmentos de grama, durante 5 dias, a 37°C. Posteriormente, os fragmentos de grama parasitados foram incubados em Meio de Indução a 37°C, por 24 horas. Observou-se que 16 amostras (50% produziram 20.000 zoósporos mL-1, 12 isolados (37,5% produziram acima de 20.000 zoósporos mL-1, enquanto quatro amostras (12,5% produziram menos de 20.000 zoósporos mL-1. O período de maior produção de zoósporos foi entre 6 e 8 horas de incubação. O protocolo utilizado na indução da zoosporogênese mostrou-se eficiente e representa uma importante ferramenta, tanto para a identificação do Pythium insidiosum, como para a obtenção de zoósporos em quantidades suficientes para a inoculação em animais experimentais e aplicação no desenvolvimento de testes de suscetibilidade.Pythium insidiosum is an aquatic oomycete and the etiology of a chronic disease called pythiosis, commonly found in the skin of horses. The production of mobile zoospores by this microorganism is the determinant factor of this disease. This study evaluated the zoosporogenesis and quantification of zoospores in 32 samples of Pythium insidiosum isolated from horses with pythiosis. The assay used culture of the Pythium insidiosum in Corn Meal Agar plus grass blades for 5 days at 37°C. The grass blades were incubated in Induction Medium at 37°C for 24 hours. The findings showed 16 samples (50% yielded 20,000 zoospores mL-1, 12 (37.5% samples yielded over 20,000 zoospores mL-1 and 4

  6. Pythium and Fusarium Species Associated with Production of Douglas-Fir Seedlings

    Science.gov (United States)

    Methyl bromide has long been used to control Pythium and Fusarium spp. in conifer nurseries in the Pacific Northwest. However, alternative fumigants are now necessary as methyl bromide is an ozone-depleting agent. The efficacy of metam sodium, dimethyl disulfide, and methyl iodide against Pythium ...

  7. Successful Medical Management of Presumptive Pythium insidiosum Keratitis.

    Science.gov (United States)

    Ramappa, Muralidhar; Nagpal, Ritu; Sharma, Savitri; Chaurasia, Sunita

    2017-04-01

    To describe the previously unreported successful treatment of presumptive Pythium keratitis (PK) with medical therapy alone. A 42-year-old female homemaker presented to us with a 15-day history of pain and redness in the right eye after a trivial injury. Her vision was 20/80 at presentation. Slit-lamp biomicroscopy revealed a central, dense and dry-looking, grayish-white infiltrate reaching mid stroma. The infiltrate had feathery margins and was surrounded by multiple tentacle-like lesions and peripherally expanding pinhead-sized subepithelial lesions. The contralateral eye was essentially normal. Diagnostic corneal scraping on smears revealed broad, aseptate, hyaline filaments with ribbon-like folds; very characteristic of Pythium species. Confocal imaging revealed fungal filaments. Based on corroborative evidence, a diagnosis of presumptive PK was made. She was administered a combination therapy consisting of eye drop linezolid 0.2% 1 hourly, azithromycin 1% 2 hourly, atropine sulfate 1% thrice daily, and oral azithromycin 500 mg once daily for 3 days in a week. After initial worsening in the form of stromal expansion, regression of pinhead-sized lesions was seen with onset of scarring by as early as day 4 of intense medical therapy. The tentacle-like lesions did not worsen. On day 8, significant resolution was noted with scarring, and by the end of 2 weeks, the entire stromal lesion had scarred and complete resolution of expanding tentacles was observed in 3 weeks. Presumptive Pythium keratitis of the patient completely resolved with antibacterial treatment alone. It is pertinent for ophthalmologists to be aware of this new treatment regimen.

  8. Two pathogenic species of Pythium: P. aphanidermatum and P. diclinum from a wheat field.

    Science.gov (United States)

    Al-Sheikh, Hashem

    2010-10-01

    During a survey of pathogenic and non-pathogenic Pythium spp. in different localities in Egypt, several isolates of Pythia were obtained and maintained on corn meal agar. Among these isolates, Pythium aphanidermatum and Pythium diclinum were obtained from rhizosphere of wheat plants grown in Dear Attia village, Minia, Egypt. Identification was made using morphological and molecular analyses. P. aphanidermatum and P. diclinum were able to cause reductions in emergence and adulating in wheat in laboratory scale. P. aphanidermatum appeared to be the most aggressive parasite under agar and pot experimental conditions.

  9. Reproducibility of suppression of Pythium wilt of cucumber by compost

    Directory of Open Access Journals (Sweden)

    Mauritz Vilhelm Vestberg

    2014-10-01

    Full Text Available There is increasing global interest in using compost to suppress soil-borne fungal and bacterial diseases and nematodes. We studied the reproducibility of compost suppressive capacity (SC against Pythium wilt of cucumber using nine composts produced by the same composting plant in 2008 and 2009. A bioassay was set up in a greenhouse using cucumber inoculated with two strains of Pythium. The composts were used as 20% mixtures (v:v of a basic steam-sterilized light Sphagnum peat and sand (3:1, v:v. Shoot height was measured weekly during the 5-week experiment. At harvest, the SC was calculated as the % difference in shoot dry weight (DW between non-inoculated and inoculated cucumbers. The SC was not affected by year of production (2008 or 2009, indicating reproducibility of SC when the raw materials and the composting method are not changed. Differences in shoot height were not as pronounced as those for shoot DW. The results were encouraging, but further studies are still needed for producing compost with guaranteed suppressiveness properties.

  10. Fast Decline of Pythium zingiberum in Soil and Its Recolonization by Cultivating Susceptible Host Plants

    OpenAIRE

    ICHITANI, Takio; SHIMIZU, Tokiya

    1984-01-01

    This experiment demonstrates the fast decline of Pythium zingiberum in soil and its recolonization by cultivating mioga, susceptible host plant, and discusses growth and survival of the pathogen in the host rhizosphere in cultivated fields.

  11. Antifungal Activity of Culture Filtrates and Organic Extracts of Aspergillus spp. against Pythium ultimum

    OpenAIRE

    Rania Aydi-Ben Abdallah; Marwa Hassine; Hayfa Jabnoun-Khiareddine; Rabiaa Haouala; Mejda Daami-Remadi

    2014-01-01

    Culture filtrates, chloroform and ethyl acetate extracts of nine isolates of Aspergillus spp. (A. niger, A. terreus, A. flavus and Aspergillus sp.), isolated from soil and compost, were tested for antifungal activity against Pythium ultimum the causal agent of the potato Pythium leak. Culture filtrates showed a significant antifungal activity at the different tested concentrations. Total inhibition of the pathogen was induced by the filtrate of CH8 of Aspergillus sp., used at 10% ...

  12. Pythium species in 13 various types of water bodies of N-E Poland

    Directory of Open Access Journals (Sweden)

    Bazyli Czeczuga

    2014-01-01

    Full Text Available Pythium species and environmental factors in various types of water bodies (2 springs, 2 rivers, 3 ponds and 6 different trophic lakes were studied. Samples of water were collected every two months (springs, rivers, ponds and every three months (lakes in the years 1996-1999 for hydrochemical analysis and in order to determine the Pythium species content. From springs rivers and ponds collected were also ice blocks for determinations of presence of Pythium species. Buckwheatand hemp-seeds, cellophane and snake exuviae were used as bait. Forty-five species of Pythium were found in various types of water bodies. Pythium acanthicum, P. complectens, P. complens, P. diameson, P. dissimile, P. elongatum, P. lucens, P. megalacanthum, P. nagae, P. oedochilum, P. oryzae, P. palingenes, P. periilum and P. polysporum were recorded for the first time in Poland. The largest mean number of species was observed in spring Cypisek, a bit fewer in spring Jaroszówka and lake Białe (oligotrophic-like waters. The lowest mean number of Pythium species was noted in pond Akcent and Pałacowy (polytrophic waters. In all types of water bodies the higest mean number of species was found in winter, and the lowest in summer.

  13. Pythium insidiosum: morphological and molecular identification of Brazilian isolates

    Directory of Open Access Journals (Sweden)

    Maria Isabel de Azevedo

    2012-07-01

    Full Text Available Pythium insidiosum is an oomycete belonging to the kingdom Stramenipila and it is the etiologic agent of pythiosis. Pythiosis is a life-threatening infectious disease characterized by the development of chronic lesions on cutaneous and subcutaneous, intestinal, and bone tissues in humans and many species of animals. The identification of P. insidiosum is important in order to implement a rapid and definitive diagnosis and an effective treatment. This study reports the identification of 54 isolates of P. insidiosum of horses, dogs and sheep that presented suspicious clinical lesions of pythiosis from different regions in Brazil, by using morphological and molecular assays. Throughout the PCR it was possible to confirm the identity of all Brazilian isolates as being P. insidiosum.

  14. Antifungal Activity from Leaves of Acacia Nilotica against Pythium Aphanidermatum

    Directory of Open Access Journals (Sweden)

    A. J. Khan

    1996-01-01

    Full Text Available Gallic acid and methyl ester of gallic acid has been identified as antifungal compounds against the mycelial growth of Pythium aphanidermatum from acetone-water extracts of Acacia nilotica leaves. The growth of fungus was completely ceased by gallic acid and its methyl ester at 1000 ppm and 750 ppm, respectively. Antifungal properties of both compounds were found to be higher in combination than alone. The minimum inhibitory concentration for both compounds was 1000 ppm. No phytotoxic effect of the compounds was observed on watermelon seed germination. The growth of roots and shoots of watermelon seedlings was promoted by gallic acid but decreased with methyl ester of gallic acid. Nitrate reductase activity of the fungus was significantly inhibited by both compounds.

  15. Phenotypic divergence along geographic gradients reveals potential for rapid adaptation of the White-nose Syndrome pathogen, Pseudogymnoascus destructans, in North America.

    Science.gov (United States)

    Forsythe, Adrian; Giglio, Victoria; Asa, Jonathan; Xu, Jianping

    2018-06-18

    White-nose Syndrome (WNS) is an ongoing epizootic affecting multiple species of North American bats, caused by epidermal infections of the psychrophilic filamentous fungus, Pseudogymnoascus destructans Since its introduction from Europe, WNS has spread rapidly across eastern North America and resulted in high mortality rates in bats. At present, the mechanisms behind its spread and the extent of its adaptation to different geographic and ecological niches remain unknown. The objective of this study was to examine the geographic patterns of phenotypic variation and the potential evidence for adaptation among strains representing broad geographic locations in eastern North America. The morphological features of these strains were evaluated on artificial medium, and the viability of asexual arthroconidia of representative strains were investigated after storage at high (23°C), moderate (14°C), and low (4°C) temperatures at different lengths of times. Our analyses identified evidence for a geographic pattern of colony morphology changes among the clonal descendants of the fungus, with trait values correlated with increased distance from the epicenter of WNS. Our genomic comparisons of three representative isolates revealed novel genetic polymorphisms and suggested potential candidate mutations that might be related to some of the phenotypic changes. These results show that even though this pathogen arrived in North America only recently and reproduces asexually, there has been substantial evolution and phenotypic diversification during its rapid clonal expansion. Importance The causal agent of White-nose Syndrome in bats is Pseudogymnoascus destructans , a filamentous fungus recently introduced from its native range in Europe. Infections caused by P. destructans have progressed across the eastern parts of Canada and the United States over the last ten years. It is not clear how the disease is spread as the pathogen is unable to grow above 23°C and ambient

  16. Etiology and epidemiology of Pythium root rot in hydroponic crops: current knowledge and perspectives

    Directory of Open Access Journals (Sweden)

    John Clifford Sutton

    2006-09-01

    Full Text Available The etiology and epidemiology of Pythium root rot in hydroponically-grown crops are reviewed with emphasis on knowledge and concepts considered important for managing the disease in commercial greenhouses. Pythium root rot continually threatens the productivity of numerous kinds of crops in hydroponic systems around the world including cucumber, tomato, sweet pepper, spinach, lettuce, nasturtium, arugula, rose, and chrysanthemum. Principal causal agents include Pythium aphanidermatum, Pythium dissotocum, members of Pythium group F, and Pythium ultimum var. ultimum. Perspectives are given of sources of initial inoculum of Pythium spp. in hydroponic systems, of infection and colonization of roots by the pathogens, symptom development and inoculum production in host roots, and inoculum dispersal in nutrient solutions. Recent findings that a specific elicitor produced by P. aphanidermatum may trigger necrosis (browning of the roots and the transition from biotrophic to necrotrophic infection are considered. Effects on root rot epidemics of host factors (disease susceptibility, phenological growth stage, root exudates and phenolic substances, the root environment (rooting media, concentrations of dissolved oxygen and phenolic substances in the nutrient solution, microbial communities and temperature and human interferences (cropping practices and control measures are reviewed. Recent findings on predisposition of roots to Pythium attack by environmental stress factors are highlighted. The commonly minor impact on epidemics of measures to disinfest nutrient solution as it recirculates outside the crop is contrasted with the impact of treatments that suppress Pythium in the roots and root zone of the crop. New discoveries that infection of roots by P. aphanidermatum markedly slows the increase in leaf area and whole-plant carbon gain without significant effect on the efficiency of photosynthesis per unit area of leaf are noted. The platform of

  17. Effect of 2,4diacetylphloroglucinol of Pythium: cellular responses and variation in sensitivity among propagules and species

    NARCIS (Netherlands)

    Souza, J.T.; Arnould, C.; Deulvot, C.; Lemanceau, P.; Gianinazzi-Pearson, V.; Raaijmakers, J.M.

    2003-01-01

    The antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) plays an important role in the suppression of plant pathogens by several strains of Pseudomonas spp. Based on the results of this study, there is variation within and among Pythium spp. to 2,4-DAPG. Also, various propagules of Pythium ultimum var.

  18. Genetic variation in Pythium myriotylum based on SNP typing and development of a PCR-RFLP detection of isolates recovered from Pythium soft rot ginger.

    Science.gov (United States)

    Le, D P; Smith, M K; Aitken, E A B

    2017-10-01

    Pythium myriotylum is responsible for severe losses in both capsicum and ginger crops in Australia under different regimes. Intraspecific genomic variation within the pathogen might explain the differences in aggressiveness and pathogenicity on diverse hosts. In this study, whole genome data of four P. myriotylum isolates recovered from three hosts and one Pythium zingiberis isolate were derived and analysed for sequence diversity based on single nucleotide polymorphisms (SNPs). A higher number of true and unique SNPs occurred in P. myriotylum isolates obtained from ginger with symptoms of Pythium soft rot (PSR) in Australia compared to other P. myriotylum isolates. Overall, SNPs were discovered more in the mitochondrial genome than those in the nuclear genome. Among the SNPs, a single substitution from the cytosine (C) to the thymine (T) in the partially sequenced CoxII gene of 14 representatives of PSR P. myriotylum isolates was within a restriction site of HinP1I enzyme which was used in the PCR-RFLP for detection and identification of the isolates without sequencing. The PCR-RFLP was also sensitive to detect PSR P. myriotylum strains from artificially infected ginger without the need for isolation for pure cultures. This is the first study of intraspecific variants of Pythium myriotylum isolates recovered from different hosts and origins based on single nucleotide polymorphism (SNP) genotyping of multiple genes. The SNPs discovered provide valuable makers for detection and identification of P. myriotylum strains initially isolated from Pythium soft rot (PSR) ginger by using PCR-RFLP of the CoxII locus. The PCR-RFLP was also sensitive to detect P. myriotylum directly from PSR ginger sampled from pot trials without the need of isolation for pure cultures. © 2017 The Society for Applied Microbiology.

  19. Efficacy of different fungicides against Rhizoctonia brown patch and Pythium blight on turfgrass in Italy.

    Science.gov (United States)

    Mocioni, M; Titone, P; Garibaldi, A; Gullino, M L

    2003-01-01

    Brown patch, incited by Rhizoctonia solani Kuhn, and Pythium blight, caused by Pythium spp. are two of the diseases most frequently observed on turfgrass in high maintenance stands, as on golf courses. In such conditions the control strategies, based on chemicals, are particularly difficult due to the scarcity of fungicides registered for turf in Italy. The results obtained in experimental trials carried out to evaluate the efficacy of chemical and biological products against brown patch and Pythium blight are reported. On mature turfgrass, maintained under fairway conditions, azoxystrobin, and trifoxystrobin, not yet registered on turf, were very effective against brown patch. Tebuconazole, applied in three different formulations, was very effective against R. solani, while Trichoderma spp. and azadiractine did not control the pathogen. In greenhouse conditions on Agrostis stolonifera, in the presence of severe disease incidence, due to artificial inoculation, benalaxyl-M satisfactorily controlled Pythium blight; Trichoderma spp. as well as a commercial formulation of T. harzianum, applied one week before the inoculation, were not effective. Among the fungicides not yet registered for use on turfgrass in Italy, metalaxyl-M + mancozeb was effective against Pythium blight.

  20. ISOLATION AND PATHOGENICITY OF A POSSIBLE Pythium aphanidermatum IN Jatropha Curcas L. NON TOXIC

    Directory of Open Access Journals (Sweden)

    Ofelia Andrea Valdes Rodriguez

    2011-03-01

    A chromista, possible Pythium aphanidermatum, was isolated from severely damage seeds and seedlings recently started from Jatropha curcas L. non toxic seeds sown in the tropical area of Veracruz, Mexico. In order to study pathogenic Pythium aphanidermatum effects over pre-emergent and post-emergent stages, seeds and young seedlings were inoculated with the isolated pathogen, and the chromista showed possible pathogenic activity against pre-emergency and recently started post-emergency; however, statistically significant damaged was not found in older seedlings.   Â

  1. Pythium root rot of common bean: biology and control methods. A review

    Directory of Open Access Journals (Sweden)

    Baudoin, JP.

    2012-01-01

    Full Text Available Pythium root rot constitutes a highly damaging constraint on the common bean, Phaseolus vulgaris L., grown in several areas of Eastern and Central Africa. Here, this food legume is cultivated intensively under poor conditions of crop rotation due to the exiguity of the land in the region. Yield losses of up to 70% in traditional local bean cultivars have been reported in Kenya and Rwanda. In this study, a detailed analysis of the biology and diversity of the Pythium genus was carried out in order to understand the mechanisms leading to the development of the disease. Various control methods for reducing the damage provoked by this disease were analyzed.

  2. Seroprevalence of Pythium insidiosum infection in equine in Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Carla Weiblen

    2016-01-01

    Full Text Available ABSTRACT: An epidemiological survey was carried out by performing an Enzyme Linked Immuno Sorbent Assay (ELISA test to determine the seroprevalence of Pythium insidiosum infection in equine in Rio Grande do Sul State (RS, Brazil. The serological study covered seven geographical regions of RS, classified according to the Instituto Brasileiro de Geografia e Estatística (IBGE. The samples were obtained from official veterinary service (Serviço Veterinário Oficial, SVO linked to the Secretaria da Agricultura, Pecuária e Agronegócio of RS (SEAPA-RS to proceed the investigation of equine infectious anemia in 2014. Samples were collected during the months of September and October of 2013, covering the seven geographical regions of RS, and totalized 1,002 serum samples. The seroprevalence for P. insidiosum in RS was 11.1% (CI95% 9.23 to 13.22. The relative risk (RR of the presence of antibodies anti-P. insidiosum was in the regions Southeast 11.17 (CI95%, 4.65 to 26.8, Porto Alegre 4.62 (CI95%, 1.70 to 12.55, Southwest 11.17 (CI95%, 4.65 to 26.8 and Northwestern 3.72 (CI95%, 1.52 to 9.09. The highest prevalence (69.1% was observed in females with RR of 1.59 (CI95%, 1.11 to 2.27. When the presence of dams was evaluated, the seropositivity was evident in 74.4%, presenting an association of 2.13 (CI95%, 1.16 to 3.91 compared to farms without dams. In properties with veterinary assistance, the frequency of 72.7% and RR of 3.04 (CI95%,, 1,85 to 4,98 of seropositivity were observed. Due to the importance of pythiosis in horse herds, this study highlights the presence of anti-P. insidiosum antibodies in horses in RS, Brazil.

  3. Leap forward in the treatment of Pythium insidiosum keratitis.

    Science.gov (United States)

    Bagga, Bhupesh; Sharma, Savitri; Madhuri Guda, Sai Jeevan; Nagpal, Ritu; Joseph, Joveeta; Manjulatha, Kodiganti; Mohamed, Ashik; Garg, Prashant

    2018-03-15

    Pythium insidiosum is a parafungus that causes keratitis resembling fungal keratitis. This study compares outcome in a large cohort of patients with P insidiosum keratitis treated with antifungal drugs, to a pilot group treated with antibacterial antibiotics. Between January 2014 and December 2016, 114 patients with culture positive P insidiosum keratitis were included in the study. A subset of culture isolates was tested in vitro for response to nine antibacterial antibiotics by disc diffusion and E test. Patients were treated with topical natamycin in 2014, 2015 and up until mid 2016. Thereafter, the patients received a combination of topical linezolid and topical and oral azithromycin. Therapeutic penetrating keratoplasty (TPK) was done for patients not responding to medical therapy. In vitro disc diffusion assay showed linezolid to be most effective. The rate of TPK was significantly higher in 2015 compared with 2016 (43/45, 95.6% vs 22/32, 68.8%; p=0.002). Eighteen patients were treated with antibacterial and 14 were treated with antifungal antibiotic in 2016. One patient was lost to follow-up in each group. The rate of TPK was higher and proportion of healed ulcers was lower (p=0.21, Fisher's exact test) in the group on antifungal therapy (TPK-11/13, 84.6%; Healed-2/13, 15.3%) compared with the group on antibacterial therapy (TPK-11/17, 64.7%; Healed-6/17, 35.2%). We report favourable but not statistically significant response of P insidiosum keratitis to antibacterial agents in a pilot series of patients. Further evaluation of this strategy in larger number of patients is recommended. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  4. Pythium invasion of plant-based life support systems: biological control and sources

    Science.gov (United States)

    Jenkins, D. G.; Cook, K. L.; Garland, J. L.; Board, K. F.; Sager, J. C. (Principal Investigator)

    2000-01-01

    Invasion of plant-based life support systems by plant pathogens could cause plant disease and disruption of life support capability. Root rot caused by the fungus, Pythium, was observed during tests of prototype plant growth systems containing wheat at the Kennedy Space Center (KSC). We conducted experiments to determine if the presence of complex microbial communities in the plant root zone (rhizosphere) resisted invasion by the Pythium species isolated from the wheat root. Rhizosphere inocula of different complexity (as assayed by community-level physiological profile: CLPP) were developed using a dilution/extinction approach, followed by growth in hydroponic rhizosphere. Pythium growth on wheat roots and concomitant decreases in plant growth were inversely related to the complexity of the inocula during 20-day experiments in static hydroponic systems. Pythium was found on the seeds of several different wheat cultivars used in controlled environmental studies, but it is unclear if the seed-borne fungal strain(s) were identical to the pathogenic strain recovered from the KSC studies. Attempts to control pathogens and their effects in hydroponic life support systems should include early inoculation with complex microbial communities, which is consistent with ecological theory.

  5. Real-time detection and quantification of Rhizoctonia and Pythium species on the Cook Agronomy Farm.

    Science.gov (United States)

    Populations of Rhizoctonia and Pythium are diverse in eastern Washington, with multiple species/anastomosis groups present throughout the region and within individual fields. The process of identifying the pathogen present in a sample is laborious and the high diversity increases the difficulty in a...

  6. Diverging Cohesion?

    DEFF Research Database (Denmark)

    Charron, Nicholas

    2016-01-01

    – which we define here as a combination of impartial bureaucratic practices, corruption and the rule of law – limits, and in some cases reverses the tendency towards greater divergence linked to trade. Countries with high levels of state capacity – that is, those that have greater government effectiveness......, stronger rule of law and lower corruption – experience lower levels of divergence, as they have the mechanisms to counterbalance the strong centripetal forces linked to openness. This claim is tested on countries that have experienced relatively high levels of increases in levels of economic and political......Why do increases in globalisation in the face of European expansion lead to sharp levels of regional divergences in wealth in some countries but not in others? The central crux of this paper is that convergence/divergence trends in European states are conditioned by ‘state capacity’. State capacity...

  7. Patogenicidade de Pythium aphanidermatum a alface cultivada em hidroponia e seu biocontrole com Trichoderma Pythium aphanidermatum pathogenicity to hydroponics lettuce and its biocontrol with Trichoderma

    Directory of Open Access Journals (Sweden)

    Katya da Silva Patekoski

    2010-08-01

    Full Text Available O objetivo deste trabalho foi avaliar a patogenicidade de Pythium aphanidermatum a variedades de alface, e a ação do produto Biotrich, formulado com Trichoderma, no controle deste patógeno e na promoção do crescimento das plantas. Em experimento in vitro, plântulas recém-germinadas das variedades de alface Vera e Elisa foram colocadas em placas de Petri com ágar-água e 1 mL de suspensão do produto Biotrich (0,2 mL L-1 e, após 24 horas, em discos com micélio do isolado de Pythium. As avaliações foram realizadas após dez dias de incubação a 20 e 31ºC. Os testes in vivo foram realizados na primavera e verão, em sistema hidropônico "Nutrient Film Technique" (NFT, em delineamento inteiramente casualizado, em esquema fatorial 2x2x2, como segue: duas variedades; presença ou ausência do patógeno; e presença ou ausência de Biotrich. Ao final do cultivo, foram avaliadas as massas de matéria fresca e seca das plantas. No experimento in vitro, P. aphanidermatum apresentou maior agressividade a 31ºC. Contudo, não foi verificada patogenicidade nos testes in vivo. De modo geral, o Biotrich não promoveu o crescimento das plantas, mas foi efetivo no controle do patógeno in vitro. Pythium aphanidermatum é patogênico às variedades de alface Vera e Elisa, a 20 e 31ºC, e o Biotrich é efetivo para o controle desse patógeno nessas temperaturas.The objective of this work was to evaluate the pathogenicity of Pythium aphanidermatum to lettuce varieties, and the action of the product Biotrich, formulated with Trichoderma, in the control of this pathogen and its effect on plant growth promotion. In a in vitro experiment, germinated seedlings of Vera and Elisa lettuce varieties were placed in Petri dishes with water-agar and 1mL Biotrich suspension (0.2 mL L-1, and after 24 hours, on plugs with the Pythium isolate mycelium. The evaluations were done ten days after the incubation at 20 and 31ºC. In vivo experiments were carried out during

  8. Pythium species from rice roots differ in virulence, host colonization and nutritional profile

    OpenAIRE

    Van Buyten, Evelien; Höfte, Monica

    2013-01-01

    Background: Progressive yield decline in Philippine aerobic rice fields has been recently associated with three closely related Pythium spp., P. arrhenomanes, P. graminicola and P. inflatum. To understand their differential virulence towards rice seedlings, we conducted a comparative survey in which three isolates each of P. arrhenomanes, P. graminicola and P. inflatum were selected to investigate host colonization, host responses and carbon utilization profiles using histopathological analys...

  9. Pythium insidiosum: inhibitory effects of propolis and geopropolis on hyphal growth

    OpenAIRE

    Araújo, Maria José Abigail Mendes; Bosco, Sandra de Moraes Gimenes; Sforcin, José Maurício

    2016-01-01

    Abstract Propolis and geopropolis are resinous products of bees showing antimicrobial effects. There is no data concerning their action against Pythium insidiosum - the causative agent of pythiosis, a pyogranulomatous disease of the subcutaneous tissue that affects mostly horses, dogs and humans. Fragments of 15 isolates of P. insidiodum were incubated with propolis and geopropolis extracts and evaluated for up to seven days to detect the minimal fungicidal concentration (MFC). Propolis inhib...

  10. A simple, rapid and inexpensive screening method for the identification of Pythium insidiosum.

    Science.gov (United States)

    Tondolo, Juliana Simoni Moraes; Loreto, Erico Silva; Denardi, Laura Bedin; Mario, Débora Alves Nunes; Alves, Sydney Hartz; Santurio, Janio Morais

    2013-04-01

    Growth of Pythium insidiosum mycelia around minocycline disks (30μg) did not occur within 7days of incubation at 35°C when the isolates were grown on Sabouraud, corn meal, Muller-Hinton or RPMI agar. This technique offers a simple and rapid method for the differentiation of P. insidiosum from true filamentous fungi. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Activity of some aminoglycoside antibiotics against true fungi, Phytophthora and Pythium species.

    Science.gov (United States)

    Lee, H B; Kim, Y; Kim, J C; Choi, G J; Park, S-H; Kim, C-J; Jung, H S

    2005-01-01

    To investigate the in vitro antifungal and antioomycete activities of some aminoglycosides against true fungi and Phytophthora and Pythium species and to evaluate the potential of the antibiotics against Phytophthora late blight on plants. Antifungal and antioomycete activities of aminoglycoside antibiotics (neomycin, paromomycin, ribostamycin and streptomycin) and a paromomycin-producing strain (Streptomyces sp. AMG-P1) against Phytophthora and Pythium species and 10 common fungi were measured in potato dextrose broth (PDB) and on seedlings in pots. Paromomycin was the most active against Phytophthora and Pythium species with a minimal inhibitory concentration of 1-10 microg ml(-1) in PDB, but displayed low to moderate activities towards other common fungi at the same concentration. Paromomycin also showed potent in vivo activity against red pepper and tomato late blight diseases with 80 and 99% control value, respectively, at 100 microg ml(-1). In addition, culture broth of Streptomyces sp. AMG-P1 as a paromomycin producer exhibited high in vivo activity against late blight at 500 microg freeze-dried weight per millilitre. Among tested aminoglycoside antibiotics, paromomycin was the most active against oomycetes both in vitro and in vivo. Data from this study show that aminoglycoside antibiotics have in vitro and in vivo activities against oomycetes, suggesting that Streptomyces sp. AMG-P1 may be used as a biocontrol agent against oomycete diseases.

  12. Pythium insidiosum: relato do primeiro caso de infecção humana no Brasil Pythium insidiosum: report of the first case of human infection in Brazil

    Directory of Open Access Journals (Sweden)

    Silvio Alencar Marques

    2006-10-01

    Full Text Available A pitiose é causada por microorganismo aquático, fungo-símile, o Pythium insidiosum, patógeno de homens e animais. Observou-se um paciente com úlcera fagedênica no membro inferior, com exame anatomopatológico sugestivo de zigomicose, pouco sensível à terapêutica antifúngica, obtendo-se cura por meio de ampla exérese. A comprovação etiológica resultou de métodos moleculares, com amplificação e seqüenciamento de DNA de organismo isolado em ágar Sabouraud, observando-se 100% de analogia com seqüências de P. insidiosum depositadas no GenBank.Pythiosis is caused by an aquatic fungus-like organism, Pythium insidiosum, pathogenic to men and animals. A patient with a phagedenic ulcer on the leg is reported. Histopathological examination was suggestive of zygomycosis, response to antifungal drugs was poor and cure was obtained by means of wide surgical excision. Etiologic diagnosis was confirmed by molecular amplification and DNA sequencing of colonies isolated in Sabouraud agar. After BLAST analysis, the sequence showed 100% identity with those of P. insidiosum deposited on the GenBank.

  13. Diverging Pathways

    DEFF Research Database (Denmark)

    Langevang, Thilde; Gough, Katherine

    2012-01-01

    Shrinking public sectors and limited opportunities for gaining formal wage employment in the private sector have resulted in entrepreneurship being promoted as a means of generating youth employment. This discourse is being widely promoted within sub-Saharan Africa despite little being known about...... of young women to enter the professions and the experiences of those that do. As the paper shows, geographers potentially have much to contribute to employment and entrepreneurship debates by providing more contextualised studies which recognise the complex interplay between globalisation, institutions...

  14. In Vitro Synergism between Azithromycin or Terbinafine and Topical Antimicrobial Agents against Pythium insidiosum

    Science.gov (United States)

    Itaqui, Sabrina R.; Verdi, Camila M.; Tondolo, Juliana S. M.; da Luz, Thaisa S.; Alves, Sydney H.; Santurio, Janio M.

    2016-01-01

    We describe here in vitro activity for the combination of azithromycin or terbinafine and benzalkonium, cetrimide, cetylpyridinium, mupirocin, triclosan, or potassium permanganate. With the exception of potassium permanganate, the remaining antimicrobial drugs were active and had an MIC90 between 2 and 32 μg∕ml. The greatest synergism was observed for the combination of terbinafine and cetrimide (71.4%). In vivo experimental evaluations will clarify the potential of these drugs for the topical treatment of lesions caused by Pythium insidiosum. PMID:27216049

  15. Geographic Names

    Data.gov (United States)

    Minnesota Department of Natural Resources — The Geographic Names Information System (GNIS), developed by the United States Geological Survey in cooperation with the U.S. Board of Geographic Names, provides...

  16. Biocontrol of Rhizoctonia solani and Pythium ultimum on Capsicum by Trichoderma koningii in potting medium.

    Science.gov (United States)

    Harris, A R

    1999-09-01

    Two isolates of Trichoderma koningii were evaluated for efficacy in control of damping-off diseases in seedlings of Capsicum annuum grown in pasteurized potting medium in a glasshouse. A selected isolate of binucleate Rhizoctonia and two fungicides were also included as standards for control of Rhizoctonia solani and Pythium ultimum var. sporangiiferum. Both isolates of T. koningii reduced seedling death caused by R. solani in one of two experiments, and by P. u. sporangii-ferum in two of three experiments. Neither isolate of T. koningii suppressed damping-off caused by either pathogen as consistently as the binucleate Rhizoctonia or fungicides. The implications of these results for commercial disease management are discussed.

  17. In vitro efficacy of bacterial endophytes against the chilli damping-off pathogen Pythium aphanidermatum

    Directory of Open Access Journals (Sweden)

    Arjunan MUTHUKUMAR

    2010-09-01

    Full Text Available Damping-off of chilli caused by Pythium aphanidermatum is a major nursery disease in vegetables. The effect of ten endophytic isolates of Pseudomonas fluorescens was tested against P. aphanidermatum under in vitro conditions. All the isolates tested were short rods and produced bright fluorescence when exposed to UV light. Among the isolates, EBS 20 produced the largest inhibition zone and the least mycelial growth of P. aphanidermatum. With regard to the secondary metabolites, P. fluorescens EBS 20 produced most salicylic acid, siderophore and hydrogen cyanide. The culture filtrate of this isolate at a 15% concentration totally inhibited mycelial growth of P. aphanidermatum. In addition, chilli seeds treated with culture filtrate of this isolate also led to the greatest plant growth in terms of root length, shoot length and vigour index.

  18. Photodynamic therapy in Pythium insidiosum - an in vitro study of the correlation of sensitizer localization and cell death.

    Directory of Open Access Journals (Sweden)

    Layla Pires

    Full Text Available Pythiosis is an infectious disease caused by Pythium insidiosum, a fungus-like organism. Due to the lack of ergosterol on its cell membrane, antibiotic therapy is ineffective. The conventional treatment is surgery, but lesion recurrence is frequent, requiring several resections or limb amputation. Photodynamic therapy uses photo-activation of drugs and has the potential to be an attractive alternative option. The in vitro PDT response on the growing of Pythium insidiosum culture was investigated using three distinct photosensitizers: methylene blue, Photogem, and Photodithazine. The photosensitizer distribution in cell structures and the PDT response for incubation times of 30, 60, and 120 minutes were evaluated. Methylene blue did not penetrate in the pathogen's cell and consequently there was no PDT inactivation. Photogem showed heterogenous distribution in the hyphal structure with small concentration inside the cells. Porphyrin-PDT response was heterogenous, death and live cells were observed in the treated culture. After 48 hours, hyphae regrowth was observed. Photodithazine showed more homogenous distribution inside the cell and with the specific intracellular localization dependent on incubation time. Photodithazine first accumulates in intracellular vacuoles, and at incubation times of one hour, it is located at all cell membranes. Higher inhibition of the growing rates was achieved with Photodithazine -PDT, over 98%. Our results showed that the photosensitizers that cross more efficiently the Pythium insidiosum membranes are able to cause extensive damage to the organism under illumination and therefore, are the best options for clinical treatment.

  19. String perturbation theory diverges

    International Nuclear Information System (INIS)

    Gross, D.J.; Periwal, V.

    1988-01-01

    We prove that perturbation theory for the bosonic string diverges for arbitrary values of the coupling constant and is not Borel summable. This divergence is independent of the existence of the infinities that occur in the theory due to the presence of tachyons and dilaton tadpoles. We discuss the physical implications of such a divergence

  20. Biochemical and genetic analyses of the oomycete Pythium insidiosum provide new insights into clinical identification and urease-based evolution of metabolism-related traits

    Directory of Open Access Journals (Sweden)

    Theerapong Krajaejun

    2018-06-01

    Full Text Available The oomycete microorganism, Pythium insidiosum, causes the life-threatening infectious condition, pythiosis, in humans and animals worldwide. Affected individuals typically endure surgical removal of the infected organ(s. Detection of P. insidiosum by the established microbiological, immunological, or molecular methods is not feasible in non-reference laboratories, resulting in delayed diagnosis. Biochemical assays have been used to characterize P. insidiosum, some of which could aid in the clinical identification of this organism. Although hydrolysis of maltose and sucrose has been proposed as the key biochemical feature useful in discriminating P. insidiosum from other oomycetes and fungi, this technique requires a more rigorous evaluation involving a wider selection of P. insidiosum strains. Here, we evaluated 10 routinely available biochemical assays for characterization of 26 P. insidiosum strains, isolated from different hosts and geographic origins. Initial assessment revealed diverse biochemical characteristics across the P. insidiosum strains tested. Failure to hydrolyze sugars is observed, especially in slow-growing strains. Because hydrolysis of maltose and sucrose varied among different strains, use of the biochemical assays for identification of P. insidiosum should be cautioned. The ability of P. insidiosum to hydrolyze urea is our focus, because this metabolic process relies on the enzyme urease, an important virulence factor of other pathogens. The ability to hydrolyze urea varied among P. insidiosum strains and was not associated with growth rates. Genome analyses demonstrated that urease- and urease accessory protein-encoding genes are present in both urea-hydrolyzing and non-urea-hydrolyzing strains of P. insidiosum. Urease genes are phylogenetically conserved in P. insidiosum and related oomycetes, while the presence of urease accessory protein-encoding genes is markedly diverse in these organisms. In summary, we dissected

  1. Pythium insidiosum: inhibitory effects of propolis and geopropolis on hyphal growth

    Directory of Open Access Journals (Sweden)

    Maria José Abigail Mendes Araújo

    Full Text Available Abstract Propolis and geopropolis are resinous products of bees showing antimicrobial effects. There is no data concerning their action against Pythium insidiosum - the causative agent of pythiosis, a pyogranulomatous disease of the subcutaneous tissue that affects mostly horses, dogs and humans. Fragments of 15 isolates of P. insidiodum were incubated with propolis and geopropolis extracts and evaluated for up to seven days to detect the minimal fungicidal concentration (MFC. Propolis inhibited three isolates at 1.0 mg mL-1 after 24 h and all other isolates at 3.4 mg mL-1. Geopropolis led to more variable results, exerting predominantly a fungistatic action than a fungicidal one. Propolis was more efficient than geopropolis in inhibiting P. insidiosum since lower concentrations led to no growth after 24 h. This effect may be due to propolis chemical composition, which has more active compounds than geopropolis. Propolis seemed to be a good candidate for in vivo studies, since treatment with conventional antifungal compounds is difficult in most of the cases, requiring extensive surgical debridement.

  2. Pythium insidiosum: inhibitory effects of propolis and geopropolis on hyphal growth.

    Science.gov (United States)

    Araújo, Maria José Abigail Mendes; Bosco, Sandra de Moraes Gimenes; Sforcin, José Maurício

    Propolis and geopropolis are resinous products of bees showing antimicrobial effects. There is no data concerning their action against Pythium insidiosum - the causative agent of pythiosis, a pyogranulomatous disease of the subcutaneous tissue that affects mostly horses, dogs and humans. Fragments of 15 isolates of P. insidiodum were incubated with propolis and geopropolis extracts and evaluated for up to seven days to detect the minimal fungicidal concentration (MFC). Propolis inhibited three isolates at 1.0mgmL -1 after 24h and all other isolates at 3.4mgmL -1 . Geopropolis led to more variable results, exerting predominantly a fungistatic action than a fungicidal one. Propolis was more efficient than geopropolis in inhibiting P. insidiosum since lower concentrations led to no growth after 24h. This effect may be due to propolis chemical composition, which has more active compounds than geopropolis. Propolis seemed to be a good candidate for in vivo studies, since treatment with conventional antifungal compounds is difficult in most of the cases, requiring extensive surgical debridement. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  3. Influence of temperature on Pythium splendens--induced root disease on carambola, Averrhoa carambola.

    Science.gov (United States)

    Ploetz, Randy C

    2004-02-01

    A series of glasshouse and incubator studies were conducted to investigate the role played by Pythium splendens in a decline disorder of carambola, Averrhoa carambola. Plants, 4-6 months old, were grown in native calcareous soil either infested or not infested with the pathogen. Isolates recovered from atemoya, carambola and passion fruit grew optimally at 30 degrees C, and significantly (P carambola. Temperature had a profound impact on the latter relationships. Two or more times more necrosis developed at 10 and 15 degrees C than at 25 and 30 degrees C. Total biomass accumulations were over four times greater at 30 degrees C than at 10 degrees C, and were always lower in soil infested with P. splendens. When biomass totals from infested and noninfested soil were compared, relative values were lowest at 15 and 20 degrees C and were almost two times greater at 30 degrees C than at 20 degrees C. Root infection by P. splendens was greatest at 15 and 20 degrees C, far below the species' optimum for growth, and at 30 degrees C was over nine times lower than at 15 and 20 degrees C. This is the first detailed report of P. splendens as a pathogen of carambola.

  4. The Patchwork Divergence Theorem

    OpenAIRE

    Dray, Tevian; Hellaby, Charles

    1994-01-01

    The divergence theorem in its usual form applies only to suitably smooth vector fields. For vector fields which are merely piecewise smooth, as is natural at a boundary between regions with different physical properties, one must patch together the divergence theorem applied separately in each region. We give an elegant derivation of the resulting "patchwork divergence theorem" which is independent of the metric signature in either region, and which is thus valid if the signature changes. (PA...

  5. Divergent Cumulative Cultural Evolution

    OpenAIRE

    Marriott, Chris; Chebib, Jobran

    2016-01-01

    Divergent cumulative cultural evolution occurs when the cultural evolutionary trajectory diverges from the biological evolutionary trajectory. We consider the conditions under which divergent cumulative cultural evolution can occur. We hypothesize that two conditions are necessary. First that genetic and cultural information are stored separately in the agent. Second cultural information must be transferred horizontally between agents of different generations. We implement a model with these ...

  6. Additional file 2: Figure S3. of Interactions between the oomycete Pythium arrhenomanes and the rice root-knot nematode Meloidogyne graminicola in aerobic Asian rice varieties

    OpenAIRE

    Verbeek, R.; Banaay, C.; Sikder, M.; De Waele, D.; Vera Cruz, C.; Gheysen, G.; Höfte, M.; Kyndt, Tina

    2016-01-01

    Pythium arrhenomanes DNA in rice roots expressed as picogram Pythium DNA per nanogram total DNA. Varieties Palawan (A) and IR81413-BB-75-4 (B) quantified with P. arrhenomanes specific and plant specific primers at 2, 10, 20, 45 and 60 days after transplanting in the raised bed experiment. ‘Natural infestation’ = soil taken from field B912 and ‘Natural infestation + P. arrhenomanes’ = B912 soil with additional P. arrhenomanes inoculation. Each treatment has two biological replicates (of three ...

  7. On infrared divergences

    International Nuclear Information System (INIS)

    Parisi, G.

    1979-01-01

    The structure of infrared divergences is studied in superrenormalizable interactions. It is conjectured that there is an extension of the Bogoliubov-Parasiuk-Hepp theorem which copes also with infrared divergences. The consequences of this conjecture on the singularities of the Borel transform in a massless asymptotic free field theory are discussed. The application of these ideas to gauge theories is briefly discussed. (Auth.)

  8. Germination of hyphal bodies of Pythium spiculum isolated from declining cork oaks at Doñana National Park (Spain

    Directory of Open Access Journals (Sweden)

    PAOLO DE VITA

    2012-01-01

    Full Text Available Pythium spiculum, a recently described new taxon, has been isolated from declining cork oaks (Quercus suber L. at Doñana National Park (south-western Spain. The microorganism can infect and cause root disease in Quercus, but currently it is unknown whether its hyphal bodies can germinate and infect host trees. These hyphal bodies, regardless of shape, have been shown to be able to germinate, producing long germ tubes, sometimes ramified. Zoospore production was not recorded, but hyphal bodies are potential host infective structures in dry soil conditions.

  9. Nuevas especies de Pythium que causan podredumbre radical de Quercus en España y Portugal

    OpenAIRE

    Vicente, M.; Sánchez Hernández, Esperanza; Trapero Casas, Antonio; Jiménez, J.J.; Fernández, P.; Serrano Moral, María Socorro

    2008-01-01

    Pythium spiculum, una nueva especie recientemente descrita, se viene aislando desde 2003 de raíces y rizosfera de Quercus rotundifolia y Q. suber que sufren decaimiento en el sur de España y Portugal. En los suelos donde crecen formaciones de Quercus, esta especie ha sido aislada con frecuencias similares a las encontradas para Phytophthora cinnamomi, especie que, hasta el momento, ha sido el único oomiceto descrito como patógeno radical de Quercus en esta región. Las inoculaciones artificial...

  10. A Leishmania murine model to evaluate the immunomodulatory properties of Pythium insidiosum proteins

    Directory of Open Access Journals (Sweden)

    Tatiana Maria Inêz-Ferreira

    2017-03-01

    Full Text Available Pythium insidiosum immunomodulatory vaccine (PiV has been tested in clinical and experimental pythiosis. Previous data showed that P. insidiosum immunogens have the ability to switch the Th2 immune response, normally in place during pythiosis, to a curative Th1 response. Pythiosis cannot be reproduced in experimental rodents with the exception of rabbits, and thus thorough evaluation of PiV´s immunomodulatory properties has been limited by the lack of a compatible inbred mouse model. In this study, we took advantage of the murine BALB/c Leishmania infection model, where infected mice produce a Th2 response, to evaluate the PiV Th2 to Th1 immunomodulatory potential. Twenty-one days following challenge with L. major, large cutaneous granulomas developed in control mice, consistent with the expected Th2 response. In contrast, Leishmania-induced cutaneous lesions in PiV-immunized mice were minimal or absent. Flow cytometry analysis of spleen cells from mice immunized with PiV and subsequently challenged with L. major displayed more CD4+ and CD8+ cells than the control group. Moreover, spleen cells from mice that were immunized with PiV then challenged with L. major secreted high levels of IFN-γ, with a moderate IL-2, IL-4, and IL-10 mixed cytokine profile upon in vitro re-stimulation with PiV. Anti-P. insidiosum IgG1 in immunized animals was present at low titers suggesting a minor immunological role for this Ig isotype in this model. Our preliminary data showed that BALB/c mice challenged with L. major represent an attractive model in which to study PiV´s immunomodulatory properties.

  11. Antibiosis functions during interactions of Trichoderma afroharzianum and Trichoderma gamsii with plant pathogenic Rhizoctonia and Pythium.

    Science.gov (United States)

    Zhang, Xinjian; Harvey, Paul R; Stummer, Belinda E; Warren, Rosemary A; Zhang, Guangzhi; Guo, Kai; Li, Jishun; Yang, Hetong

    2015-09-01

    Trichoderma afroharzianum is one of the best characterized Trichoderma species, and strains have been utilized as plant disease suppressive inoculants. In contrast, Trichoderma gamsii has only recently been described, and there is limited knowledge of its disease suppressive efficacies. Comparative studies of changes in gene expression during interactions of these species with their target plant pathogens will provide fundamental information on pathogen antibiosis functions. In the present study, we used complementary DNA amplified fragment length polymorphism (cDNA-AFLP) analysis to investigate changes in transcript profiling of T. afroharzianum strain LTR-2 and T. gamsii strain Tk7a during in vitro interactions with plant pathogenic Rhizoctonia solani and Pythium irregulare. Considerable differences were resolved in the overall expression profiles of strains LTR-2 and Tk7a when challenged with either plant pathogen. In strain LTR-2, previously reported mycoparasitism-related genes such as chitinase, polyketide synthase, and non-ribosomal peptide synthetase were found to be differentially expressed. This was not so for strain Tk7a, with the only previously reported antibiosis-associated genes being small secreted cysteine-rich proteins. Although only one differentially expressed gene was common to both strains LTR-2 and Tk7a, numerous genes reportedly associated with pathogen antibiosis processes were differentially expressed in both strains, including degradative enzymes and membrane transport proteins. A number of novel potential antibiosis-related transcripts were found from strains LTR-2 and Tk7a and remain to be identified. The expression kinetics of 20 Trichoderma (10 from strain LTR-2, 10 from strain Tk7a) transcript-derived fragments (TDFs) were quantified by quantitative reverse transcription PCR (RT-qPCR) at pre- and post-mycelia contact stages of Trichoderma-prey interactions, thereby confirming differential gene expression. Collectively, this research

  12. Efeito da temperatura no crescimento micelial e patogenicidade de Pythium spp. que ocorrem em alface hidropônica Temperature effects on mycelial growth and pathogenicity of Pythium spp. occuring in hydroponic lettuce

    Directory of Open Access Journals (Sweden)

    Liliane De Diana Teixeira

    2006-09-01

    Full Text Available Doze isolados de Pythium foram obtidos de raízes de alface cultivada em sistemas hidropônicos comerciais, apresentando ou não sintomas de apodrecimento. Três desses isolados foram identificados como Pythium helicoides Drechsler (H1, H2 e H3, cinco como pertencentes ao grupo F (F1 a F5 e quatro ao grupo T (T1 a T4 de Pythium. A identificação das espécies foi realizada baseando-se nas características morfológicas. O efeito da temperatura (10, 15, 18, 21, 24, 27, 30, 37 e 40ºC sobre o crescimento micelial foi determinado para todos os isolados. As temperaturas mínima e máxima, estimadas pela função beta generalizada, variaram de 3,5 a 10ºC e de 40 a 40,7ºC, respectivamente. A temperatura ótima foi de 24 a 37ºC para P. helicoides, de 25 a 35ºC para o isolado F4 e de 21 a 30ºC para os demais isolados. A patogenicidade e a agressividade dos isolados foram avaliadas, inoculando-se sementes de alface cv. Verônica, semeadas em ágar-água, a 21 e 30ºC. A 30ºC, os isolados de P. helicoides foram notadamente os mais agressivos, ocasionando 100 % de mortalidade das sementes logo após sua germinação. A 21ºC, todos os isolados induziram subdesenvolvimento de plântulas, acompanhado ou não de necrose dos tecidos radiculares. Trata-se do primeiro relato de P. helicoides para o Brasil e a primeira referência mundial da espécie em hidroponia.Twelve Pythium isolates were obtained from lettuce roots grown hydroponically in commercial systems, showing or not symptoms of rotting. Three of them were identified as P. helicoides (H1, H2 and H3, whereas five were shown to belong to group F (F1-F5 and four to group T (T1-T4 of Pythium. The identification of the species was based on morphological characteristics. The effect of temperature (10, 15, 18, 21, 24, 27, 30, 37 and 40ºC on the mycelial growth was determined for all isolates. Minimum and maximum temperatures, estimated by the generalized beta function, varied from 3.5 to 10ºC and 40

  13. Quantum skew divergence

    Energy Technology Data Exchange (ETDEWEB)

    Audenaert, Koenraad M. R., E-mail: koenraad.audenaert@rhul.ac.uk [Department of Mathematics, Royal Holloway University of London, Egham TW20 0EX, United Kingdom and Department of Physics and Astronomy, University of Ghent, S9, Krijgslaan 281, B-9000 Ghent (Belgium)

    2014-11-15

    In this paper, we study the quantum generalisation of the skew divergence, which is a dissimilarity measure between distributions introduced by Lee in the context of natural language processing. We provide an in-depth study of the quantum skew divergence, including its relation to other state distinguishability measures. Finally, we present a number of important applications: new continuity inequalities for the quantum Jensen-Shannon divergence and the Holevo information, and a new and short proof of Bravyi's Small Incremental Mixing conjecture.

  14. Geographical Tatoos

    Directory of Open Access Journals (Sweden)

    Valéria Cazetta

    2014-08-01

    Full Text Available The article deals with maps tattooed on bodies. My interest in studying the corporeality is inserted in a broader project entitled Geographies and (in Bodies. There is several published research on tattoos, but none in particular about tattooed maps. However some of these works interested me because they present important discussions in contemporary about body modification that helped me locate the body modifications most within the culture than on the nature. At this time, I looked at pictures of geographical tattoos available in several sites of the internet.

  15. Biocontrol traits of plant growth suppressive arbuscular mycorrhizal fungi against root rot in tomato caused by Pythium aphanidermatum

    DEFF Research Database (Denmark)

    Larsen, John; Graham, James H.; Cubero, Jaime

    2012-01-01

    Arbuscular mycorrhizal (AM) fungi known to cause plant growth depressions in tomato were examined for their biocontrol effects against root rot caused by Pythium aphanidermatum. The main hypothesis was that plant growth suppressive AM fungi would elicit a defence response in the host plant reduci...

  16. Evaluation of seed coating formulations of Trichoderma harzianum on cucumber seeds against pre- and post-emergence damping-off caused by Pythium ultimum

    Science.gov (United States)

    Seed coating formulations of Trichoderma harzianum were evaluated on cucumber seeds to control pre- and post-emergence damping-off caused by Pythium ultimum in greenhouse studies. Results showed that coating formulation H reduced the disease incidence significantly, and had the potential for commer...

  17. Biological control of Pythium aphanidermatum in cucumber with a combined application of Lysobacter enzymogenes strain 3.1T8 and chitosan

    NARCIS (Netherlands)

    Postma, J.; Stevens, L.H.; Wiegers, G.L.; Davelaar, E.; Nijhuis, E.H.

    2009-01-01

    Pythium aphanidermatum (Edson) Fitzp., causing root and crown rot in cucumber, was successfully managed by Lysobacter enzymogenes strain 3.1T8. Greenhouse experiments were performed with cucumber plants grown in rockwool blocks up to 5 weeks with a recirculated nutrient solution. Application of L.

  18. Development of SCAR markers and PCR assays for single or simultaneous species-specific detection of Phytophthora nicotianae and Pythium helicoides in ebb-and-flow irrigated kalanchoe.

    Science.gov (United States)

    Ahonsi, Monday O; Ling, Yin; Kageyama, Koji

    2010-11-01

    Phytophthora nicotianae and Pythium helicoides are important water-borne oomycete pathogens of irrigated ornamentals particularly ebb-and-flow irrigated kalanchoe in Japan. We developed novel PCR-based sequence characterized amplified region markers and assays for rapid identification and species-specific detection of both pathogens in separate PCR reactions or simultaneously in a duplex PCR.

  19. Population Structure of Pythium irregulare, P. ultimum, and P. sylvaticum in Forest Nursery Soils of Oregon and Washington.

    Science.gov (United States)

    Weiland, Jerry E; Garrido, Patricia; Kamvar, Zhian N; Espíndola, Andrés S; Marek, Stephen M; Grünwald, Niklaus J; Garzón, Carla D

    2015-05-01

    Pythium species are important soilborne pathogens occurring in the forest nursery industry of the Pacific Northwest. However, little is known about their genetic diversity or population structure and it is suspected that isolates are moved among forest nurseries on seedling stock and shared field equipment. In order to address these concerns, a total of 115 isolates of three Pythium species (P. irregulare, P. sylvaticum, and P. ultimum) were examined at three forest nurseries using simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) markers. Analyses revealed distinct patterns of intraspecific variation for the three species. P. sylvaticum exhibited the most diversity, followed by P. irregulare, while substantial clonality was found in P. ultimum. For both P. irregulare and P. sylvaticum, but not P. ultimum, there was evidence for significant variation among nurseries. However, all three species also exhibited at least two distinct lineages not associated with the nursery of origin. Finally, evidence was found that certain lineages and clonal genotypes, including fungicide-resistant isolates, are shared among nurseries, indicating that pathogen movement has occurred.

  20. Use of dry-milling derived thin stillage for producing eicosapentaenoic acid (EPA) by the fungus Pythium irregulare.

    Science.gov (United States)

    Liang, Yi; Zhao, Xuefei; Strait, Megan; Wen, Zhiyou

    2012-05-01

    This study was to explore the use of thin stillage, a major byproduct in dry milling corn-ethanol plants, for production of eicosapentaenoic acid (EPA) by the fungus Pythium irregulare. Thin stillage contains various compounds that were ideal for fungal growth. Thin stillage concentration and temperature played important roles in fungal growth and EPA production. When 50% thin stillage was used in a stepwise temperature shift culture process, the cell density reached 23 g/L at day 9 with EPA yield and productivity of 243 and 27 mg/L day, respectively. The fungal biomass contained 39% lipid, 28% protein, 30% carbohydrate, and 3% ash. The fungal culture also generated a nutrient-depleted liquid by removing organic compounds in the raw thin stillage. The results collectively showed a new use of thin stillage by feeding to the fungus P. irregulare for producing omega-3 fatty acids. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Molecular phylogenetics and anti-Pythium activity of endophytes from rhizomes of wild ginger congener, Zingiber zerumbet Smith.

    Science.gov (United States)

    Keerthi, D; Aswati Nair, R; Prasath, D

    2016-03-01

    Zingiber zerumbet, a perennial rhizomatous herb exhibits remarkable disease resistance as well as a wide range of pharmacological activities. Towards characterizing the endophytic population of Z. zerumbet rhizomes, experiments were carried out during two different growing seasons viz., early-June of 2013 and late-July of 2014. A total of 34 endophytes were isolated and categorized into 11 morphologically distinct groups. Fungi were observed to predominate bacterial species with colonization frequency values ranging from 12.5 to 50%. Among the 11 endophyte groups isolated, molecular analyses based on ITS/16S rRNA gene sequences identified seven isolate groups as Fusarium solani, two as F. oxysporum and one as the bacterium Rhizobium spp. Phylogenetic tree clustered the ITS sequences from Z. zerumbet endophytes into distinct clades consistent with morphological and sequence analysis. Dual culture assays were carried out to determine antagonistic activity of the isolated endophytes against Pythium myriotylum, an economically significant soil-borne phytopathogen of cultivated ginger. Experiments revealed significant P. myriotylum growth inhibition by F. solani and F. oxysporum isolates with percentage of inhibition (PoI) ranging from 45.17 ± 0.29 to 62.2 ± 2.58 with F. oxysporum exhibiting higher PoI values against P. myriotylum. Using ZzEF8 metabolite extract, concentration-dependent P. myriotylum hyphal growth inhibition was observed following radial diffusion assays. These observations were confirmed by scanning electron microscopy analysis wherein exposure to ZzEF8 metabolite extract induced hyphal deformities. Results indicate Z. zerumbet endophytes as promising resources for biologically active compounds and as biocontrol agents for soft rot disease management caused by Pythium spp.

  2. The elicitin-like glycoprotein, ELI025, is secreted by the pathogenic oomycete Pythium insidiosum and evades host antibody responses.

    Directory of Open Access Journals (Sweden)

    Tassanee Lerksuthirat

    Full Text Available Pythium insidiosum is a unique oomycete that can infect humans and animals. Patients with a P. insidiosum infection (pythiosis have high rates of morbidity and mortality. The pathogen resists conventional antifungal drugs. Information on the biology and pathogenesis of P. insidiosum is limited. Many pathogens secrete proteins, known as effectors, which can affect the host response and promote the infection process. Elicitins are secretory proteins and are found only in the oomycetes, primarily in Phytophthora and Pythium species. In plant-pathogenic oomycetes, elicitins function as pathogen-associated molecular pattern molecules, sterol carriers, and plant defense stimulators. Recently, we reported a number of elicitin-encoding genes from the P. insidiosum transcriptome. The function of elicitins during human infections is unknown. One of the P. insidiosum elicitin-encoding genes, ELI025, is highly expressed and up-regulated at body temperature. This study aims to characterize the biochemical, immunological, and genetic properties of the elicitin protein, ELI025. A 12.4-kDa recombinant ELI025 protein (rELI025 was expressed in Escherichia coli. Rabbit anti-rELI025 antibodies reacted strongly with the native ELI025 in P. insidiosum's culture medium. The detected ELI025 had two isoforms: glycosylated and non-glycosylated. ELI025 was not immunoreactive with sera from pythiosis patients. The region near the transcriptional start site of ELI025 contained conserved oomycete core promoter elements. In conclusion, ELI025 is a small, abundant, secreted glycoprotein that evades host antibody responses. ELI025 is a promising candidate for development of diagnostic and therapeutic targets for pythiosis.

  3. Sites of infection by pythium species in rice seedlings and effects of plant age and water depth on disease development.

    Science.gov (United States)

    Chun, S C; Schneider, R W

    1998-12-01

    ABSTRACT Seedling disease, caused primarily by several species of Pythium, is one of the major constraints to water-seeded rice production in Louisiana. The disease, also known as water-mold disease, seed rot, and seedling damping-off, causes stand reductions and growth abnormalities. In severe cases, fields must be replanted, which may result in delayed harvests and reduced yields. To develop more effective disease management tactics including biological control, this study was conducted primarily to determine sites of infection in seeds and seedlings; effect of plant age on susceptibility to P. arrhenomanes, P. myriotylum, and P. dissotocum; and minimum exposure times required for infection and seedling death. In addition, the effect of water depth on seedling disease was investigated. Infection rates of seed embryos were significantly higher than those of endosperms for all three Pythium spp. The development of roots from dry-seeded seedlings was significantly reduced by P. arrhenomanes and P. myriotylum at 5 days after planting compared with that of roots from noninoculated controls. Susceptibility of rice to all three species was sharply reduced within 2 to 6 days after planting, and seedlings were completely resistant at 8 days after planting. There was a steep reduction in emergence through the flood water, relative to the noninoculated control, following 2 to 3 days of exposure to inoculum of P. arrhenomanes and P. myriotylum. In contrast, P. dissotocum was much less virulent and required longer exposure times to cause irreversible seedling damage. Disease incidence was higher when seeds were planted into deeper water, implying that seedlings become resistant after they emerge through the flood water. These results suggest that disease control tactics including flood water management need to be employed for a very short period of time after planting. Also, given that the embryo is the primary site of infection and it is susceptible for only a few days, the

  4. Converging or Diverging Lens?

    Science.gov (United States)

    Branca, Mario

    2013-01-01

    Why does a lens magnify? Why does it shrink objects? Why does this happen? The activities that we propose here are useful in helping us to understand how lenses work, and they show that the same lens can have different magnification capabilities. A converging lens can also act as a diverging lens. (Contains 4 figures.)

  5. Testing evolutionary hypotheses for phenotypic divergence using landscape genetics.

    Science.gov (United States)

    Funk, W Chris; Murphy, Melanie A

    2010-02-01

    Understanding the evolutionary causes of phenotypic variation among populations has long been a central theme in evolutionary biology. Several factors can influence phenotypic divergence, including geographic isolation, genetic drift, divergent natural or sexual selection, and phenotypic plasticity. But the relative importance of these factors in generating phenotypic divergence in nature is still a tantalizing and unresolved problem in evolutionary biology. The origin and maintenance of phenotypic divergence is also at the root of many ongoing debates in evolutionary biology, such as the extent to which gene flow constrains adaptive divergence (Garant et al. 2007) and the relative importance of genetic drift, natural selection, and sexual selection in initiating reproductive isolation and speciation (Coyne & Orr 2004). In this issue, Wang & Summers (2010) test the causes of one of the most fantastic examples of phenotypic divergence in nature: colour pattern divergence among populations of the strawberry poison frog (Dendrobates pumilio) in Panama and Costa Rica (Fig. 1). This study provides a beautiful example of the use of the emerging field of landscape genetics to differentiate among hypotheses for phenotypic divergence. Using landscape genetic analyses, Wang & Summers were able to reject the hypotheses that colour pattern divergence is due to isolation-by-distance (IBD) or landscape resistance. Instead, the hypothesis left standing is that colour divergence is due to divergent selection, in turn driving reproductive isolation among populations with different colour morphs. More generally, this study provides a wonderful example of how the emerging field of landscape genetics, which has primarily been applied to questions in conservation and ecology, now plays an essential role in evolutionary research.

  6. Local divergence and curvature divergence in first order optics

    Science.gov (United States)

    Mafusire, Cosmas; Krüger, Tjaart P. J.

    2018-06-01

    The far-field divergence of a light beam propagating through a first order optical system is presented as a square root of the sum of the squares of the local divergence and the curvature divergence. The local divergence is defined as the ratio of the beam parameter product to the beam width whilst the curvature divergence is a ratio of the space-angular moment also to the beam width. It is established that the beam’s focusing parameter can be defined as a ratio of the local divergence to the curvature divergence. The relationships between the two divergences and other second moment-based beam parameters are presented. Their various mathematical properties are presented such as their evolution through first order systems. The efficacy of the model in the analysis of high power continuous wave laser-based welding systems is briefly discussed.

  7. Draft genome sequences of the oomycete Pythium insidiosum strain CBS 573.85 from a horse with pythiosis and strain CR02 from the environment

    Directory of Open Access Journals (Sweden)

    Preecha Patumcharoenpol

    2018-02-01

    Full Text Available Pythium insidiosum is an aquatic oomycete microorganism that causes the fatal infectious disease, pythiosis, in humans and animals. The organism has been successfully isolated from the environment worldwide. Diagnosis and treatment of pythiosis is difficult and challenging. Genome sequences of P. insidiosum, isolated from humans, are available and accessible in public databases. To further facilitate biology-, pathogenicity-, and evolution-related genomic and genetic studies of P. insidiosum, we report two additional draft genome sequences of the P. insidiosum strain CBS 573.85 (35.6 Mb in size; accession number, BCFO00000000.1 isolated from a horse with pythiosis, and strain CR02 (37.7 Mb in size; accession number, BCFR00000000.1 isolated from the environment. Keywords: Pythium insidiosum, Pythiosis, Draft genome sequence

  8. Whole genome sequence of the emerging oomycete pathogen Pythium insidiosum strain CDC-B5653 isolated from an infected human in the USA

    Directory of Open Access Journals (Sweden)

    Marina S. Ascunce

    2016-03-01

    Full Text Available Pythium insidiosum ATCC 200269 strain CDC-B5653, an isolate from necrotizing lesions on the mouth and eye of a 2-year-old boy in Memphis, Tennessee, USA, was sequenced using a combination of Illumina MiSeq (300 bp paired-end, 14 millions reads and PacBio (10  Kb fragment library, 356,001 reads. The sequencing data were assembled using SPAdes version 3.1.0, yielding a total genome size of 45.6 Mb contained in 8992 contigs, N50 of 13 Kb, 57% G + C content, and 17,867 putative protein-coding genes. This Whole Genome Shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession JRHR00000000. Keywords: Oomycete, Pythium insidiosum, Pythiosis, Human emerging pathogen, Genome sequencing

  9. Convergence from divergence

    Science.gov (United States)

    Costin, Ovidiu; Dunne, Gerald V.

    2018-01-01

    We show how to convert divergent series, which typically occur in many applications in physics, into rapidly convergent inverse factorial series. This can be interpreted physically as a novel resummation of perturbative series. Being convergent, these new series allow rigorous extrapolation from an asymptotic region with a large parameter, to the opposite region where the parameter is small. We illustrate the method with various physical examples, and discuss how these convergent series relate to standard methods such as Borel summation, and also how they incorporate the physical Stokes phenomenon. We comment on the relation of these results to Dyson’s physical argument for the divergence of perturbation theory. This approach also leads naturally to a wide class of relations between bosonic and fermionic partition functions, and Klein-Gordon and Dirac determinants.

  10. Regularization of divergent integrals

    OpenAIRE

    Felder, Giovanni; Kazhdan, David

    2016-01-01

    We study the Hadamard finite part of divergent integrals of differential forms with singularities on submanifolds. We give formulae for the dependence of the finite part on the choice of regularization and express them in terms of a suitable local residue map. The cases where the submanifold is a complex hypersurface in a complex manifold and where it is a boundary component of a manifold with boundary, arising in string perturbation theory, are treated in more detail.

  11. Predictors for reproductive isolation in a ring species complex following genetic and ecological divergence.

    Science.gov (United States)

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

    2011-07-06

    Reproductive isolation (RI) is widely accepted as an important "check point" in the diversification process, since it defines irreversible evolutionary trajectories. Much less consensus exists about the processes that might drive RI. Here, we employ a formal quantitative analysis of genetic interactions at several stages of divergence within the ring species complex Ensatina eschscholtzii in order to assess the relative contribution of genetic and ecological divergence for the development of RI. By augmenting previous genetic datasets and adding new ecological data, we quantify levels of genetic and ecological divergence between populations and test how they correlate with a restriction of genetic admixture upon secondary contact. Our results indicate that the isolated effect of ecological divergence between parental populations does not result in reproductively isolated taxa, even when genetic transitions between parental taxa are narrow. Instead, processes associated with overall genetic divergence are the best predictors of reproductive isolation, and when parental taxa diverge in nuclear markers we observe a complete cessation of hybridization, even to sympatric occurrence of distinct evolutionary lineages. Although every parental population has diverged in mitochondrial DNA, its degree of divergence does not predict the extent of RI. These results show that in Ensatina, the evolutionary outcomes of ecological divergence differ from those of genetic divergence. While evident properties of taxa may emerge via ecological divergence, such as adaptation to local environment, RI is likely to be a byproduct of processes that contribute to overall genetic divergence, such as time in geographic isolation, rather than being a direct outcome of local adaptation.

  12. EFEITO DE DIFERENTES CONCENTRAÇÕES DE BENOMYL E PCNB SOBRE O CRESCIMENTO RADIAL DE Fusarium solani E Pythium sp., IN VITRO EFFECT OF DIFFERENT CONCENTRATIONS OF BENOMYL AND PCNB ON THE RADIAL GROWTH OF Fusarium solani AND Pythium sp. IN VITRO

    Directory of Open Access Journals (Sweden)

    Luciana Peliz Machado

    2007-09-01

    Full Text Available

    Os experimentos foram realizado nas dependências do Laboratório de Fitopatologia da Universidade Federal de Goiás, no ano de 1997. Os fungos Fusarium e Pythium sp. foram cultivados em meio de cultura artificial contendo benomyl e PCNB nas concentrações de 10, 25, 50 e 100ppm. Os crescimentos radiais dos fungos demonstraram que o benomyl foi eficiente contra o Fusarium, mas não surtiu efeito contra o Pythium, fato este também observado em relação ao PCNB. Este produto, embora menos eficiente, reduziu em mais de 50% o crescimento radial de Fusarium, obtendo uma redução progressiva com o aumento da concentração.

    PALAVRAS-CHAVE: Fusarium; Pythium; benomyl; quintozene.

    The experiments were carried out at Laboratory of Phytopathology of the Escola de Agronomia of the Universidade Federal de Goiás, in the year of 1997. The fungi Fusarium moniliforme and Pythium sp. were treated in cultural medium with benomyl and PCNB in the concentrations of 10, 25, 50 e 100ppm. The radial growth of the fungi demonstrated that benomyl was efficient against Fusarium, but not against Pythium sp. The same was also observed with PCNB. Although less efficient than benomyl, this product reduced radial growth of Fusarium in more than 50%. The increase of PCNB concentration reduced Fusarium growth progressively.

    KEY-WORDS: Fusarium; Pythium; benomyl; PCNB.

  13. Divergent Perturbation Series

    International Nuclear Information System (INIS)

    Suslov, I.M.

    2005-01-01

    Various perturbation series are factorially divergent. The behavior of their high-order terms can be determined by Lipatov's method, which involves the use of instanton configurations of appropriate functional integrals. When the Lipatov asymptotic form is known and several lowest order terms of the perturbation series are found by direct calculation of diagrams, one can gain insight into the behavior of the remaining terms of the series, which can be resummed to solve various strong-coupling problems in a certain approximation. This approach is demonstrated by determining the Gell-Mann-Low functions in φ 4 theory, QED, and QCD with arbitrary coupling constants. An overview of the mathematical theory of divergent series is presented, and interpretation of perturbation series is discussed. Explicit derivations of the Lipatov asymptotic form are presented for some basic problems in theoretical physics. A solution is proposed to the problem of renormalon contributions, which hampered progress in this field in the late 1970s. Practical perturbation-series summation schemes are described both for a coupling constant of order unity and in the strong-coupling limit. An interpretation of the Borel integral is given for 'non-Borel-summable' series. Higher order corrections to the Lipatov asymptotic form are discussed

  14. Nonfeed application of rendered animal proteins for microbial production of eicosapentaenoic acid by the fungus Pythium irregulare.

    Science.gov (United States)

    Liang, Yi; Garcia, Rafael A; Piazza, George J; Wen, Zhiyou

    2011-11-23

    Rendered animal proteins are well suited for animal nutrition applications, but the market is maturing, and there is a need to develop new uses for these products. The objective of this study is to explore the possibility of using animal proteins as a nutrient source for microbial production of omega-3 polyunsaturated fatty acids by the microalga Schizochytrium limacinum and the fungus Pythium irregulare. To be absorbed by the microorganisms, the proteins needed to be hydrolyzed into small peptides and free amino acids. The utility of the protein hydrolysates for microorganisms depended on the hydrolysis method used and the type of microorganism. The enzymatic hydrolysates supported better cell growth performance than the alkali hydrolysates did. P. irregulare displayed better overall growth performance on the experimental hydrolysates compared to S. limacinum. When P. irregulare was grown in medium containing 10 g/L enzymatic hydrolysate derived from meat and bone meal or feather meal, the performance of cell growth, lipid synthesis, and omega-3 fatty acid production was comparable to the that of culture using commercial yeast extract. The fungal biomass derived from the animal proteins had 26-29% lipid, 32-34% protein, 34-39% carbohydrate, and industrial microorganisms which can produce omega-3 fatty acids for making omega-3-fortified foods or feeds.

  15. Obstrução intestinal por Pythium insidiosum em um cão: relato de caso

    Directory of Open Access Journals (Sweden)

    P.S. Hunning

    2010-08-01

    Full Text Available Relata-se um caso de pitiose intestinal em um Husky Siberiano, de um ano de idade, macho atendido em um Hospital Veterinário Escola com sinais de obstrução intestinal. Ao exame físico, notou-se massa cilíndrica na região abdominal cranial, posteriormente confirmada por meio de radiografia e ultrassonografia. Durante a laparotomia exploratória, constatou-se massa extraluminal envolvendo o jejuno e alterações na parede do órgão. Realizou-se a ressecção da porção afetada do intestino e, posteriormente, anastomose. O exame histológico do tecido evidenciou inflamação piogranulomatosa acentuada. Na coloração de prata metenamina de Grocott, hifas septadas foram observadas. O diagnóstico de infecção por Pythium insidiosum foi confirmado por meio da imunoistoquímica. Após a cirurgia, o animal restabeleceu a defecação; no 30° dia pós-cirúrgico, foi relatada ainda presença de diarreia. O tratamento com itraconazol e terbinafina foi instituído durante 60 dias. Após dois anos do procedimento cirúrgico e do tratamento com antifúngicos orais, o cão não apresentou recidiva.

  16. Evaluation of Trichoderma spp. for biocontrol of tomato sudden caused by Pythium aphanidermatum following flooding in tropical hot season.

    Science.gov (United States)

    Le, H T T; Black, L L; Sikora, R A

    2003-01-01

    Tomato sudden death is a major problem in tomato production in tropical lowland areas. The plant wilts and dies following artificial or natural flooding for 48-72 hrs in the summer season. Occurrence of this disease is related to aggressiveness of Pythium aphanidermatum on tomato at high soil temperature (>30 degrees C). Several methods such as using biological control agents, fungicides and other cultural practices were applied in attempts to control tomato sudden death. Three Trichoderma harzianum and two Trichoderma virens isolates were evaluated for biocontrol of the disease in the greenhouse and in the field T. harzianum and T. virens isolates were separately used to treat the seed, potting medium and also incorporated into the soil before transplanting. Field soil was naturally infested with P. aphanidermatum, while greenhouse soil was inoculated with the pathogen 10 days after transplanting. All treatments were flooded for 48 hrs at 32 degrees C soil temperature. Results from this study show that most tested T. harzianum and T. virens isolates have little promise for control of tomato sudden death following flooding. The percentage of tomato plants that wilted after growing in soil treated with either T. harzianum or T. virens and P. aphanidermatum was not significantly different when compared to the soil treated with P. aphanidermatum alone. No wilted plants were observed in the control (non treated soil).

  17. Geographical information systems

    DEFF Research Database (Denmark)

    Möller, Bernd

    2004-01-01

    The chapter gives an introduction to Geographical Information Systems (GIS) with particular focus on their application within environmental management.......The chapter gives an introduction to Geographical Information Systems (GIS) with particular focus on their application within environmental management....

  18. Quadratic divergences and dimensional regularisation

    International Nuclear Information System (INIS)

    Jack, I.; Jones, D.R.T.

    1990-01-01

    We present a detailed analysis of quadratic and quartic divergences in dimensionally regulated renormalisable theories. We perform explicit three-loop calculations for a general theory of scalars and fermions. We find that the higher-order quartic divergences are related to the lower-order ones by the renormalisation group β-functions. (orig.)

  19. Genomic islands of divergence are not affected by geography of speciation in sunflowers.

    Science.gov (United States)

    Renaut, S; Grassa, C J; Yeaman, S; Moyers, B T; Lai, Z; Kane, N C; Bowers, J E; Burke, J M; Rieseberg, L H

    2013-01-01

    Genomic studies of speciation often report the presence of highly differentiated genomic regions interspersed within a milieu of weakly diverged loci. The formation of these speciation islands is generally attributed to reduced inter-population gene flow near loci under divergent selection, but few studies have critically evaluated this hypothesis. Here, we report on transcriptome scans among four recently diverged pairs of sunflower (Helianthus) species that vary in the geographical context of speciation. We find that genetic divergence is lower in sympatric and parapatric comparisons, consistent with a role for gene flow in eroding neutral differences. However, genomic islands of divergence are numerous and small in all comparisons, and contrary to expectations, island number and size are not significantly affected by levels of interspecific gene flow. Rather, island formation is strongly associated with reduced recombination rates. Overall, our results indicate that the functional architecture of genomes plays a larger role in shaping genomic divergence than does the geography of speciation.

  20. Geographic Media Literacy

    Science.gov (United States)

    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…

  1. Complex interaction of deferasirox and Pythium insidiosum: iron-dependent attenuation of growth in vitro and immunotherapy-like enhancement of immune responses in vivo.

    Directory of Open Access Journals (Sweden)

    Régis A Zanette

    Full Text Available Pythium insidiosum iron acquisition mechanisms are unknown. We previously showed that the iron chelator deferasirox had weak activity in vitro and in rabbits with experimental pythiosis. Here we show that deferasirox causes damage to P. insidiosum hyphae in vitro, but that activity is diminished in the presence of exogenous iron. The tissue activity of the proinflammatory enzyme adenosine deaminase and the histological pattern observed in pythiosis lesions of rabbits treated with deferasirox were similar to the ones in animals treated with immunotherapy.

  2. Surface motility in Pseudomonas sp DSS73 is required for efficient biological containment of the root-pathogenic microfungi Rhizoctonia solani and Pythium ultimum

    DEFF Research Database (Denmark)

    Andersen, Jens Bo; Koch, Birgit; Nielsen, T.H.

    2003-01-01

    Pseudomonas sp. DSS73 was isolated from the rhizoplane of sugar beet seedlings. This strain exhibits antagonism towards the root-pathogenic microfungi Pythium ultimum and Rhizoctonia solani. Production of the cyclic lipopeptide amphisin in combination with expression of flagella enables the growing......-pathogenic microfungi is shown to arise from amphisin-dependent surface translocation and growth by which the bacterium can lay siege to the fungi. The synergistic effects of surface motility and synthesis of a battery of antifungal compounds efficiently contain and terminate growth of the microfungi....

  3. Is mitochondrial DNA divergence of near easter crested newts, Triturus karelinii group, reflected by differentiation of skull shape

    NARCIS (Netherlands)

    Ivanovic, A.; Uzum, N.; Wielstra, B.M.; Olgun, K.; Litvinchuk, S.N.; Kalezic, M.L.; Arntzen, J.W.

    2013-01-01

    The Eurasian Triturus karelinii group of crested newts comprises three distinct, geographically coherent mitochondrial DNA lineages, designated as the eastern, central and western lineage. These three lineages are genetically as diverged as other, morphologically well-differentiated crested newt

  4. Resposta sorológica de coelhos imunizados com antígenos de Pythium insidiosum associados a diferentes adjuvantes Serological response in rabbits immunized with Pythium insidiosum antigens associated with different adjuvants

    Directory of Open Access Journals (Sweden)

    Alexandre Trindade Leal

    2002-12-01

    Full Text Available O Pythium insidiosum é um fungo zoospórico que se desenvolve em locais alagadiços e que pode infectar humanos e animais, principalmente eqüinos. A infecção natural nesta espécie resulta em pitiose clínica, uma doença granulomatosa de difícil tratamento. Uma das opções terapêuticas é a imunoterapia com antígenos obtidos de culturas do agente. Com o objetivo de avaliar o efeito de adjuvantes na resposta sorológica a antígenos do P. insidiosum, 24 coelhos divididos em 4 grupos foram imunizados com antígeno macerado de micélio (AMM associado a três adjuvantes. Grupo I: hidróxido de alumínio; grupo II: adjuvante de Freund; grupo III: óleo mineral e grupo IV: água destilada -controle. Os tratamentos foram avaliados a diferentes intervalos, quanto à capacidade de induzir a produção de imunoglobulinas específicas da classe G, através da técnica de ELISA. Na fase 1, os animais receberam três doses do imunógeno (dias zero, 14 e 28 e foram avaliados sorologicamente nos dias 14, 21, 28 e 35. Nessa fase, os adjuvantes oleosos (GII e III induziram níveis de anticorpos estatisticamente superiores aos induzidos nos grupos I e IV. Durante a fase 2 (dias 42 a 120, cada grupo foi subdividido em dois; sendo um subgrupo mantido em tratamento (imunizações adicionais nos dias 42, 56, 68 e 82 e o outro tendo o tratamento interrompido após a 3ª dose (dia 28. Nos subgrupos mantidos em tratamento, os níveis de anticorpos dos grupos imunizados com adjuvantes foram estatisticamente superiores aos induzidos no grupo GIV (controle. Nos coelhos com tratamento interrompido, os grupos I, II e III apresentaram manutenção nos níveis de IgG e foram estatisticamente superiores ao grupo controle, que apresentou declínio nos níveis de anticorpos. Os resultados demonstraram a capacidade dos adjuvantes testados em potencializar e prolongar a resposta humoral aos antígenos do P. insidiosum. O uso de adjuvantes associado aos atuais imun

  5. Analyses between Reproductive Behavior, Genetic Diversity and Pythium Responsiveness in Zingiber spp. Reveal an Adaptive Significance for Hemiclonality

    Science.gov (United States)

    Thomas, Geethu E.; Geetha, Kiran A.; Augustine, Lesly; Mamiyil, Sabu; Thomas, George

    2016-01-01

    Mode of reproduction is generally considered to have long-range evolutionary implications on population survival. Because sexual reproduction produces genetically diverse genotypes, this mode of reproduction is predicted to positively influence the success potential of offspring in evolutionary arms race with parasites (Red queen) whereas, without segregation and recombination, the obligate asexual multiplication may push a species into extinction due to the steady accumulation of deleterious mutations (Muller’s ratchet). However, the extent of linearity between reproductive strategies, genetic diversity and population fitness, and the contributions of different breeding strategies to population fitness are yet to be understood clearly. Genus Zingiber belonging to the pan-tropic family Zingiberaceae represents a good system to study contributions of different breeding behavior on genetic diversity and population fitness, as this genus comprises species with contrasting breeding systems. In this study, we analyzed breeding behavior, amplified fragment length polymorphism diversity and response to the soft-rot pathogen Pythium aphanidermatum in 18 natural populations of three wild Zingiber spp.: Z. neesanum, Z. nimmonii, and Z. zerumbet, together with the obligately asexual cultivated congener, ginger (Z. officinale). Ginger showed an exceptionally narrow genetic base, and adding to this, all the tested cultivars were uniformly susceptible to soft-rot. Concordant with the postulates of Muller’s ratchet, the background selection may be continuously pushing ginger into the ancestral state, rendering it inefficient in host-pathogen coevolution. Z. neesanum and Z. nimmonii populations were sexual and genetically diverse; however, contrary to Red Queen expectations, the populations were highly susceptible to soft-rot. Z. zerumbet showed a hemiclonal breeding behavior. The populations inhabiting forest understory were large and continuous, sexual and genetically

  6. Fungal endophytes of turmeric (Curcuma longa L.) and their biocontrol potential against pathogens Pythium aphanidermatum and Rhizoctonia solani.

    Science.gov (United States)

    Vinayarani, G; Prakash, H S

    2018-03-14

    Endophytic fungi have been isolated from the healthy turmeric (Curcuma longa L.) rhizomes from South India. Thirty-one endophytes were identified based on morphological and ITS-rDNA sequence analysis. The isolated endophytes were screened for antagonistic activity against Pythium aphanidermatum (Edson) Fitzp., and Rhizoctonia solani Kuhn., causing rhizome rot and leaf blight diseases in turmeric respectively. Results revealed that only six endophytes showed > 70% suppression of test pathogens in antagonistic dual culture assays. The endophyte T. harzianum TharDOB-31 showed significant in vitro mycelial growth inhibition of P. aphanidermatum (76.0%) and R. solani (76.9%) when tested by dual culture method. The SEM studies of interaction zone showed morphological abnormalities like parasitism, shriveling, breakage and lysis of hyphae of the pathogens by endophyte TharDOB-31. Selected endophytic isolates recorded multiple plant growth promoting traits in in vitro studies. The rhizome bacterization followed by soil application of endophyte TharDOB-31 showed lowest Percent Disease Incidence of rhizome rot and leaf blight, 13.8 and 11.6% respectively. The treatment of TharDOB-31 exhibited significant increase in plant height (85 cm) and fresh rhizome yield/plant (425 g) in comparison with untreated control under greenhouse condition. The confocal microscopy validates the colonization of the TharDOB-31 in turmeric rhizomes. The secondary metabolites in ethyl acetate extract of TharDOB-31 were found to contain higher number of antifungal compounds by high resolution liquid chromatograph mass spectrometer analysis. Thereby, endophyte T. harzianum isolate can be exploited as a potential biocontrol agent for suppressing rhizome rot and leaf blight diseases in turmeric.

  7. Moss Pathogenesis-Related-10 protein enhances resistance to Pythium irregulare in Physcomitrella patens and Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Alexandra eCastro

    2016-04-01

    Full Text Available Plants respond to pathogen infection by activating signaling pathways leading to the accumulation of proteins with diverse roles in defense. Here, we addressed the functional role of PpPR-10, a pathogenesis-related (PR-10 gene, of the moss Physcomitrella patens, in response to biotic stress. PpPR-10 belongs to a multigene family and encodes a protein twice the usual size of PR-10 proteins due to the presence of two Bet v1 domains. Moss PR-10 genes are differentially regulated during development and inoculation with the fungal pathogen Botrytis cinerea. Specifically, PpPR-10 transcript levels increase significantly by treatments with elicitors of Pectobacterium carotovorum subsp. carotovorum, spores of B. cinerea, and the defense hormone salicylic acid. To characterize the role of PpPR-10 in plant defense against pathogens, we conducted overexpression analysis in P. patens and in Arabidopsis thaliana. We demonstrate that constitutive expression of PpPR-10 in moss tissues increased resistance against the oomycete Pythium irregulare. PpPR-10 overexpressing moss plants developed less symptoms and decreased mycelium growth than wild type plants. In addition, PpPR-10 overexpressing plants constitutively produced cell wall depositions in protonemal tissue. Ectopic expression of PpPR-10 in Arabidopsis resulted in increased resistance against P. irregulare as well, evidenced by smaller lesions and less cellular damage compared to wild type plants. These results indicate that PpPR-10 is functionally active in the defense against the pathogen P. irregulare, in both P. patens and Arabidopsis, two evolutionary distant plants. Thus, P. patens can serve as an interesting source of genes to improve resistance against pathogen infection in flowering plants.

  8. Transcriptional and Antagonistic Responses of Biocontrol Strain Lysobacter enzymogenes OH11 to the Plant Pathogenic Oomycete Pythium aphanidermatum

    Directory of Open Access Journals (Sweden)

    Yangyang Zhao

    2017-06-01

    Full Text Available Lysobacter enzymogenes is a ubiquitous, beneficial, plant-associated bacterium emerging as a novel biological control agent. It has the potential to become a new source of antimicrobial secondary metabolites such as the Heat-Stable Antifungal Factor (HSAF, which is a broad-spectrum antimycotic with a novel mode of action. However, very little information about how L. enzymogenes detects and responds to fungi or oomycetes has been reported. An in vitro confrontation bioassay between the pathogenic oomycete Pythium aphanidermatum and the biocontrol bacterial strain L. enzymogenes OH11 was used to analyze the transcriptional changes in the bacteria that were induced by the oomycetes. Analysis was performed at three time points of the interaction, starting before inhibition zone formation until inhibition zone formation. A L. enzymogenes OH11 DNA microarray was constructed for the analysis. Microarray analysis indicated that a wide range of genes belonging to 14 diverse functions in L. enzymogenes were affected by P. aphanidermatum as critical antagonistic effects occurred. L. enzymogenes detected and responded to the presence of P. aphanidermatum early, but alteration of gene expression typically occurred after inhibition zone formation. The presence of P. aphanidermatum increased the twitching motility and HSAF production in L. enzymogenes. We also performed a contact interaction between L. enzymogenes and P. aphanidermatum, and found that HSAF played a critical role in the interaction. Our experiments demonstrated that L. enzymogenes displayed transcriptional and antagonistic responses to P. aphanidermatum in order to gain advantages in the competition with this oomycete. This study revealed new insights into the interactions between bacteria and oomycete.

  9. Linear energy divergences in Coulomb gauge QCD

    OpenAIRE

    Andrasi, A.

    2011-01-01

    The structure of linear energy divergences is analysed on the example of one graph to 3-loop order. Such dangerous divergences do cancel when all graphs are added, but next to leading divergences do not cancel out.

  10. Effects of piperidine and piperideine alkaloids from the venom of red imported fire ants, Solenopsis invicta Buren, on Pythium ultimum Trow growth in vitro and the application of piperideine alkaloids to control cucumber..

    Science.gov (United States)

    Pythium ultimum Trow is a plant pathogen that causes significant yield losses on many economically important crops. Chemical seed treatment has been used for disease control. In searching for alternatives, the venom alkaloids from red imported fire ant were tested against P. ultimum in vitro and to ...

  11. Isolamento e caracterização de espécies de Pythium de ambientes aquáticos no Estado do Rio Grande do Sul e avaliação da patogenicidade em modelo experimental

    Directory of Open Access Journals (Sweden)

    Cristina G. Zambrano

    Full Text Available RESUMO: Foram coletadas 186 amostras de água de ambientes pantanosos em 13 municípios das regiões Sul, Central e Oeste do Rio Grande do Sul, Brasil, com o objetivo de isolar e caracterizar espécies de Pythium e avaliar a sua patogenicidade empregando coelhos como modelo experimental. Em 11,8% (n=22 das águas coletadas foram isoladas diferentes espécies de Pythium incluindo: P. insidiosum (n=1, P. catenulatum (n=3, P. pachycaule voucher (n=1, P. rhizo-oryzae (n=3, P. torulosum (n=4 e Pythium spp. (n=10. Zoósporos desses micro-organismos foram produzidos in vitro e inoculados por via subcutânea em coelhos, os quais foram avaliados durante 45 dias. Dentre os oomicetos testados, apenas P. insidiosum evidenciou patogenicidade, causando pitiose no modelo experimental, evidenciando que, em nossas condições, apenas esta espécie de Pythium é patógena para mamíferos.

  12. Draft genome and sequence variant data of the oomycete Pythium insidiosum strain Pi45 from the phylogenetically-distinct Clade-III

    Directory of Open Access Journals (Sweden)

    Weerayuth Kittichotirat

    2017-12-01

    Full Text Available Pythium insidiosum is a unique oomycete microorganism, capable of infecting humans and animals. The organism can be phylogenetically categorized into three distinct clades: Clade-I (strains from the Americas; Clade-II (strains from Asia and Australia, and Clade–III (strains from Thailand and the United States. Two draft genomes of the P. insidiosum Clade-I strain CDC-B5653 and Clade-II strain Pi-S are available in the public domain. The genome of P. insidiosum from the distinct Clade-III, which is distantly-related to the other two clades, is lacking. Here, we report the draft genome sequence of the P. insidiosum strain Pi45 (also known as MCC13; isolated from a Thai patient with pythiosis; accession numbers BCFM01000001-BCFM01017277 as a representative strain of the phylogenetically-distinct Clade-III. We also report a genome-scale data set of sequence variants (i.e., SNPs and INDELs found in P. insidiosum (accessible online at the Mendeley database: http://dx.doi.org/10.17632/r75799jy6c.1. Keywords: Pythium insidiosum, Pythiosis, Draft genome, Sequence variant

  13. In-Vitro Inhibition of Pythium ultimum, Fusarium graminearum, and Rhizoctonia solani by a Stabilized Lactoperoxidase System alone and in Combination with Synthetic Fungicides

    Directory of Open Access Journals (Sweden)

    Zachariah R. Hansen

    2017-11-01

    Full Text Available Advances in enzyme stabilization and immobilization make the use of enzymes for industrial applications increasingly feasible. The lactoperoxidase (LPO system is a naturally occurring enzyme system with known antimicrobial activity. Stabilized LPO and glucose oxidase (GOx enzymes were combined with glucose, potassium iodide, and ammonium thiocyanate to create an anti-fungal formulation, which inhibited in-vitro growth of the plant pathogenic oomycete Pythium ultimum, and the plant pathogenic fungi Fusarium graminearum and Rhizoctonia solani. Pythium ultimum was more sensitive than F. graminearum and R. solani, and was killed at LPO and GOx concentrations of 20 nM and 26 nM, respectively. Rhizoctonia solani and F. graminearum were 70% to 80% inhibited by LPO and GOx concentrations of 242 nM and 315 nM, respectively. The enzyme system was tested for compatibility with five commercial fungicides as co-treatments. The majority of enzyme + fungicide co-treatments resulted in additive activity. Synergism ranging from 7% to 36% above the expected additive activity was observed when P. ultimum was exposed to the enzyme system combined with Daconil® (active ingredient (AI: chlorothalonil 29.6%, GardenTech, Lexington, KY, USA, tea tree oil, and mancozeb at select fungicide concentrations. Antagonism was observed when the enzyme system was combined with Tilt® (AI: propiconazole 41.8%, Syngenta, Basel, Switzerland at one fungicide concentration, resulting in activity 24% below the expected additive activity at that concentration.

  14. Boiling flow through diverging microchannel

    Indian Academy of Sciences (India)

    such systems, for small pressure drop penalty and with good flow stability. .... ied the effect of divergence angle on mean and transient pressure/temperature distribution and .... supplying a fixed voltage and current using a power source meter.

  15. Atmospheric horizontal divergence and diffusion

    International Nuclear Information System (INIS)

    Castans, M.

    1981-01-01

    The action of horizontal divergence on diffusion near the ground is established through.a very simple flow model. The shape of the well-known Pasquill-Gifford-Turner curves, that apparently take account in some way of divergence, is justified. The possibility of explaining the discre--pancies between the conventional straight line model and experimental results, mainly under low-wind-speed satable conditions, is considered. Some hints for further research are made. (auth.)

  16. Airports Geographic Information System -

    Data.gov (United States)

    Department of Transportation — The Airports Geographic Information System maintains the airport and aeronautical data required to meet the demands of the Next Generation National Airspace System....

  17. Manejo de Pythium sp. y Rhizoctonia solani Kuhn en bancos de enraizamiento de Gypsophila paniculata L. Management of Pythium sp. and Rhizoctonía solaní kuhn in rooting benches of Gypsophíla paniculata L.

    Directory of Open Access Journals (Sweden)

    Garcés de Granada Emira

    1994-12-01

    Full Text Available

    En este trabajo, se evaluó el efecto que sobre los patógenos Pythium sp. Y Rhizoctonia solani Kuhn., tienen los aislamientos de Trichoderma harzianum (T 17 y T 13 y Trichoderma sp. (T18, lo mismo que tratamientos químicos aplicados en bancos de enraizamiento de Gypsophila paniculata L., con altos índices de contaminación. Para evaluar el control de la pudrición del cuello de la raíz de Gypsophila paniculata L., se realizaron observaciones semanales en las cuales se tuvieron en cuenta los porcentajes de esquejes sanos, de esquejes muertos y de esquejes en los cuales se desarrollaban raíces. Los resultados muestran que es más efectivo el control de la pudrición con la aplicación semanal de fungicidas. Sin embargo, se recomienda el empleo de cepas de Trichoderma sp., pero aplicadas con una frecuencia, por lo menos igual, a la empleada con los fungicidas, ya que se observa su efecto inmediato, pero no permanente y, además, porque parecen influir sobre el desarrollo de las plantas.

  18. Analyses between Reproductive Behaviour, Genetic Diversity and Pythium Responsiveness in Zingiber spp. reveal an adaptive significance for hemiclonality

    Directory of Open Access Journals (Sweden)

    Geethu Elizabath Thomas

    2016-12-01

    Full Text Available AbstractMode of reproduction is generally considered to have long-range evolutionary implications on population survival. Because sexual reproduction produces genetically diverse genotypes, this mode of reproduction is predicted to positively influence the success potential of offspring in evolutionary arms race with parasites (Red queen whereas, without segregation and recombination, the obligate asexual multiplication may push a species into extinction due to the steady accumulation of deleterious mutations (Muller’s ratchet. However, the extent of linearity between reproductive strategies, genetic diversity and population fitness, and the contributions of different breeding strategies to population fitness are yet to be understood clearly. Genus Zingiber belonging to the pan-tropic family Zingiberaceae represents a good system to study contributions of different breeding behaviour on genetic diversity and population fitness, as this genus comprises species with contrasting breeding systems. In this study, we analyzed breeding behaviour, amplified fragment length polymorphism (AFLP diversity and response to the soft-rot pathogen Pythium aphanidermatum in 18 natural populations of three wild Zingiber spp.: Z. neesanum, Z. nimmonii and Z. zerumbet, together with the obligately asexual cultivated congener, ginger (Z. officinale. Ginger showed an exceptionally narrow genetic base, and adding to this, all the tested cultivars were uniformly susceptible to soft-rot. Concordant with the postulates of Muller’s ratchet, the background selection may be continuously pushing ginger into the ancestral state, rendering it inefficient in host-pathogen coevolution. Z. neesanum and Z. nimmonii populations were sexual and genetically diverse; however, contrary to Red Queen expectations, the populations were highly susceptible to soft-rot. Z. zerumbet showed a hemiclonal breeding behaviour. The populations inhabiting forest understory were large and

  19. Control of Chinese-kale damping-off caused by Pythium aphanidermatum by antifungal metabolites of Trichoderma virens

    Directory of Open Access Journals (Sweden)

    Chiradej Chamswarng

    2007-07-01

    Full Text Available Seven strains of Trichoderma virens were isolated from Chinese-kale planting soil in Nakhon Si Thammarat province. Efficacy of those isolates to inhibit mycelial growth and overgrow on mycelia ofPythium aphanidermatum, a causal agent of damping-off on Chinese-kale, were determined by a dual culture test. All strains significantly inhibited growth and overgrew on mycelia of P. aphanidermatum on potato dextrose agar (PDA as compared with the control. Strains T-NST-01, T-NST-05 and T-NST-07 gave high values of inhibition by 85.5, 82.5 and 78.5%, respectively. For efficacy to overgrow on mycelia of pathogen test, strains T-NST-05, T-NST-07 and T-NST-01 provided 48.3, 47.0 and 46.1% of mycelial overgrowth, respectively. Antifungal metabolites were extracted from three promising strains and tested against mycelial growth and sporangium production of P. aphanidermatum. The results showed that 1,000 mg/L of all metabolites completely inhibited mycelial growth and sporangium production. Under laboratory condition, all metabolites (1,000 mg/L significantly increased the number of Chinese-kale seedling germination, especially the metabolites from T-NST-01 and T-NST-07 provided germination of 92.5 and 87.5%, respectively. Under glasshouse conditions, Chinese-kale seedlings treated with 1,000 mg/L of metabolites from strains T-NST-01 and T-NST-07 survived by 90.5 and 87.5%, respectively, while the control 1 (sterile water and control 2 (2% methanol had 19.0 and 18.5% of survived seedlings, respectively. In P. aphanidermatum viability test, mycelia of P. aphanidermatum treated with antifungal metabolites from three strains of T. virens showed no visible growth, while the control with 2% methanol or sterile water, mycelia of P. aphanidermatum rapidly grew and covered whole surface of PDA in of the Petri dish within 4 days.

  20. String loop divergences and effective lagrangians

    International Nuclear Information System (INIS)

    Fischler, W.; Klebanov, I.; Susskind, L.

    1988-01-01

    We isolate logarithmic divergences from bosonic string amplitudes on a disc. These divergences are compared with 'tadpole' divergences in the effective field theory, with a covariant cosmological term implied by the counting of string coupling constants. We find an inconsistency between the two. This might be a problem in eliminating divergences from the bosonic string. (orig.)

  1. Semantic search during divergent thinking.

    Science.gov (United States)

    Hass, Richard W

    2017-09-01

    Divergent thinking, as a method of examining creative cognition, has not been adequately analyzed in the context of modern cognitive theories. This article casts divergent thinking responding in the context of theories of memory search. First, it was argued that divergent thinking tasks are similar to semantic fluency tasks, but are more constrained, and less well structured. Next, response time distributions from 54 participants were analyzed for temporal and semantic clustering. Participants responded to two prompts from the alternative uses test: uses for a brick and uses for a bottle, for two minutes each. Participants' cumulative response curves were negatively accelerating, in line with theories of search of associative memory. However, results of analyses of semantic and temporal clustering suggested that clustering is less evident in alternative uses responding compared to semantic fluency tasks. This suggests either that divergent thinking responding does not involve an exhaustive search through a clustered memory trace, but rather that the process is more exploratory, yielding fewer overall responses that tend to drift away from close associates of the divergent thinking prompt. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Hyperreal Numbers for Infinite Divergent Series

    OpenAIRE

    Bartlett, Jonathan

    2018-01-01

    Treating divergent series properly has been an ongoing issue in mathematics. However, many of the problems in divergent series stem from the fact that divergent series were discovered prior to having a number system which could handle them. The infinities that resulted from divergent series led to contradictions within the real number system, but these contradictions are largely alleviated with the hyperreal number system. Hyperreal numbers provide a framework for dealing with divergent serie...

  3. Chained Kullback-Leibler Divergences

    Science.gov (United States)

    Pavlichin, Dmitri S.; Weissman, Tsachy

    2017-01-01

    We define and characterize the “chained” Kullback-Leibler divergence minw D(p‖w) + D(w‖q) minimized over all intermediate distributions w and the analogous k-fold chained K-L divergence min D(p‖wk−1) + … + D(w2‖w1) + D(w1‖q) minimized over the entire path (w1,…,wk−1). This quantity arises in a large deviations analysis of a Markov chain on the set of types – the Wright-Fisher model of neutral genetic drift: a population with allele distribution q produces offspring with allele distribution w, which then produce offspring with allele distribution p, and so on. The chained divergences enjoy some of the same properties as the K-L divergence (like joint convexity in the arguments) and appear in k-step versions of some of the same settings as the K-L divergence (like information projections and a conditional limit theorem). We further characterize the optimal k-step “path” of distributions appearing in the definition and apply our findings in a large deviations analysis of the Wright-Fisher process. We make a connection to information geometry via the previously studied continuum limit, where the number of steps tends to infinity, and the limiting path is a geodesic in the Fisher information metric. Finally, we offer a thermodynamic interpretation of the chained divergence (as the rate of operation of an appropriately defined Maxwell’s demon) and we state some natural extensions and applications (a k-step mutual information and k-step maximum likelihood inference). We release code for computing the objects we study. PMID:29130024

  4. Controlling the root and stem rot of cucumber, caused by Pythium aphanidermatum, using resistance cultivars and grafting onto the cucurbit rootstocks

    Directory of Open Access Journals (Sweden)

    Fatemeh Rostami

    2015-02-01

    Full Text Available Cucumber damping off caused by Pythium aphanidermatum is the most important root and stem rot that limits greenhouse cultivations. In this study, relative susceptibility of grafting commercial cucumber cultivars including Alpha, Caspian 340, Storm 5910, Shalim 616, Delta scar, Janette 810, Festibal C5, Royal, Negyn, Soltan and Fadia on two Cucurbita rootstocks were evaluated against P. aphanidermatum . Disease severity, survival and seedling growth were used for the evaluation. The results showed significant differences between the studied cultivars (p≤0.01. Caspian 340 and Alpha with 15.7% and 100% disease severity had more and less tolerant to P. aphanidermatum, respectively. Cucurbita maxima rootstock was more resistant than Cucurbita pepo to P. aphanidermatum. C. pepo had less compatibility with the cucumber and showed little resistance to the pathogen. The study revealed that grafting Caspian340 on the resistant cucurbit rootstock i.e. Cucurbita maxima could be used as disease control strategies in greenhouses.

  5. Primeira ocorrência de Pythium sp. E Rhizoctonia sp. causando podridão-de-raízes em ervais no Rio Grande do Sul

    Directory of Open Access Journals (Sweden)

    Igor Poletto

    2007-01-01

    Full Text Available In 2004, some plantations of Ilex paraguariensis A. St.-Hil. In Taquari Valley, state of Rio Grande do Sul, started presenting growth stagnation, yellowing, leaf drop and necrosis in the root system, typical symptoms of root rot. Roots samples were collected in farms of two cities and sent for analysis at the Plant Disease Laboratory at the Department of Plant Protection/CCR/UFSM. The presence of Rhizoctonia and Pythium was diagnosed and these were pathogenic when inoculated in plants of erva-mate. This is the first observation of these two fungi causing root rot in erva-mate plantations in the state of Rio Grande do Sul, Brasil.

  6. Use of cross-flow membrane filtration in a recirculating hydroponic system to suppress root disease in pepper caused by Pythium myriotylum.

    Science.gov (United States)

    Schuerger, Andrew C; Hammer, William

    2009-05-01

    Zoosporic pathogens in the genera Pythium and Phytophthora cause extensive root disease epiphytotics in recirculating hydroponic vegetable-production greenhouses. Zoospore cysts of Pythium myriotylum Drechsler were used to evaluate the effectiveness of cross-flow membrane filters to control pythiaceous pathogens in recirculating hydroponic systems. Four membrane filter brands (Honeycomb, Polypure, Polymate, and Absolife) were tested alone or in combination to determine which filters would effectively remove infective propagules of P. myriotylum from solutions and reduce disease incidence and severity. Zoospore cysts of P. myriotylum generally measured 8 to 10 microm, and it was hypothesized that filters with pore-sizespepper plants from root infection. Single-filter assays with Honeycomb and Polypure brands removed 85 to 95% of zoospore cysts when pore sizes were rated at 1, 5, 10, 20, or 30 microm. Single-filter assays of Polymate and Absolife brands were more effective, exhibiting apparently 100% removal of zoospore cysts from nutrient solutions on filters rated at 1 to 10 microm. However, plant bioassays with Honeycomb and Polymate single filters failed to give long-term protection of pepper plants. Double-filter assays with 1- and 0.5-microm Polymate filters significantly increased the protection of pepper plants grown in nutrient film technique systems but, eventually, root disease and plant wilt could be observed. Insect transmissions by shore flies were not factors in disease development. Scanning electron microscopy images of zoospore cysts entrapped on Polymate filters revealed zoospore cysts that were either fully encysted, partially encysted, or of unusually small size (3 microm in diameter). It was concluded that either the atypically small or pliable pleomorphic zoospore cysts were able to penetrate filter membranes that theoretically should have captured them.

  7. Podridão de raízes causada por Pythium aphanidermatum, em cultivares de alface produzidas em sistema hidropônico

    Directory of Open Access Journals (Sweden)

    Zayame Vegette Pinto

    2011-12-01

    Full Text Available A podridão de raízes, causada por Pythium aphanidermatum e outras espécies de Pythium, é a principal doença da alface cultivada em sistemas hidropônicos no Brasil. O presente trabalho teve como objetivo avaliar quatro cultivares comerciais de alface em relação à sensibilidade a podridão de raízes, causada por P. aphanidermatum. Os estudos foram realizados em placas de Petri contendo ágar-água com plântulas de alface das cultivares crespa (Vera e Verônica e lisa (Regina e Elisa, infestadas ou não com o patógeno. Com as mesmas cultivares foram realizados quatro experimentos em sistemas hidropônicos (Nutrient Film Technique, sendo dois em estufa coberta com plástico e sombrite e dois em estufa coberta apenas com plástico. As plântulas, infectadas ou não com P. aphanidermatum, foram transplantadas para os sistemas infestados ou não. Foi avaliada a severidade da doença e o desenvolvimento das plantas. Todas as cultivares foram suscetíveis à podridão de raízes nos experimentos realizados in vitro e in vivo. A presença do sombrite não reduziu a podridão de raízes em cultivares de alface produzidas no sistema hidropônico. A cultivar Regina apresentou maior massa de matéria seca da parte aérea e das raízes, na presença ou ausência do patógeno, sendo a mais indicada para o cultivo hidropônico na época mais quente do ano.

  8. Phylogeography of speciation: allopatric divergence and secondary contact between outcrossing and selfing Clarkia.

    Science.gov (United States)

    Pettengill, James B; Moeller, David A

    2012-09-01

    The origins of hybrid zones between parapatric taxa have been of particular interest for understanding the evolution of reproductive isolation and the geographic context of species divergence. One challenge has been to distinguish between allopatric divergence (followed by secondary contact) versus primary intergradation (parapatric speciation) as alternative divergence histories. Here, we use complementary phylogeographic and population genetic analyses to investigate the recent divergence of two subspecies of Clarkia xantiana and the formation of a hybrid zone within the narrow region of sympatry. We tested alternative phylogeographic models of divergence using approximate Bayesian computation (ABC) and found strong support for a secondary contact model and little support for a model allowing for gene flow throughout the divergence process (i.e. primary intergradation). Two independent methods for inferring the ancestral geography of each subspecies, one based on probabilistic character state reconstructions and the other on palaeo-distribution modelling, also support a model of divergence in allopatry and range expansion leading to secondary contact. The membership of individuals to genetic clusters suggests geographic substructure within each taxon where allopatric and sympatric samples are primarily found in separate clusters. We also observed coincidence and concordance of genetic clines across three types of molecular markers, which suggests that there is a strong barrier to gene flow. Taken together, our results provide evidence for allopatric divergence followed by range expansion leading to secondary contact. The location of refugial populations and the directionality of range expansion are consistent with expectations based on climate change since the last glacial maximum. Our approach also illustrates the utility of combining phylogeographic hypothesis testing with species distribution modelling and fine-scale population genetic analyses for inferring

  9. Genetic divergence is decoupled from ecological diversification in the Hawaiian Nesosydne planthoppers.

    Science.gov (United States)

    Roesch Goodman, Kari; Welter, Stephen C; Roderick, George K

    2012-09-01

    Adaptive radiation involves ecological shifts coupled with isolation of gene pools. However, we know little about what drives the initial stages of divergence. We study a system in which ecological diversification is found within a chronologically well-defined geological matrix to provide insight into this enigmatic phase of radiation. We tested the hypothesis that a period of geographic isolation precedes ecological specialization in an adaptive radiation of host-specialized Hawaiian planthoppers. We examined population structure and history using mitochondrial and multiple independent microsatellite loci in a species whose geographic distribution on the island of Hawaii enabled us to observe the chronology of divergence in its very earliest stages. We found that genetic divergence is associated with geographic features but not different plant hosts and that divergence times are very recent and on the same timescales as the dynamic geology of the island. Our results suggest an important role for geography in the dynamics of the early stages of divergence. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  10. Island biology and morphological divergence of the Skyros wall lizard Podarcis gaigeae: a combined role for local selection and genetic drift on color morph frequency divergence?

    Directory of Open Access Journals (Sweden)

    Runemark Anna

    2010-09-01

    Full Text Available Abstract Background Patterns of spatial variation in discrete phenotypic traits can be used to draw inferences about the adaptive significance of traits and evolutionary processes, especially when compared to patterns of neutral genetic variation. Population divergence in adaptive traits such as color morphs can be influenced by both local ecology and stochastic factors such as genetic drift or founder events. Here, we use quantitative color measurements of males and females of Skyros wall lizard, Podarcis gaigeae, to demonstrate that this species is polymorphic with respect to throat color, and the morphs form discrete phenotypic clusters with limited overlap between categories. We use divergence in throat color morph frequencies and compare that to neutral genetic variation to infer the evolutionary processes acting on islet- and mainland populations. Results Geographically close islet- and mainland populations of the Skyros wall lizard exhibit strong divergence in throat color morph frequencies. Population variation in throat color morph frequencies between islets was higher than that between mainland populations, and the effective population sizes on the islets were small (Ne:s ST for throat color morph frequencies fell within the neutral FST-distribution estimated from microsatellite markers, and genetic drift could thus not be rejected as an explanation for the pattern. Moreover, for both comparisons among mainland-mainland population pairs and between mainland-islet population pairs, morph frequency divergence was significantly correlated with neutral divergence, further pointing to some role for genetic drift in divergence also at the phenotypic level of throat color morphs. Conclusions Genetic drift could not be rejected as an explanation for the pattern of population divergence in morph frequencies. In spite of an expected stabilising selection, throat color frequencies diverged in the islet populations. These results suggest that

  11. On Hölder Projective Divergences

    KAUST Repository

    Nielsen, Frank

    2017-03-16

    We describe a framework to build distances by measuring the tightness of inequalities and introduce the notion of proper statistical divergences and improper pseudo-divergences. We then consider the Holder ordinary and reverse inequalities and present two novel classes of Holder divergences and pseudo-divergences that both encapsulate the special case of the Cauchy-Schwarz divergence. We report closed-form formulas for those statistical dissimilarities when considering distributions belonging to the same exponential family provided that the natural parameter space is a cone (e.g., multivariate Gaussians) or affine (e.g., categorical distributions). Those new classes of Holder distances are invariant to rescaling and thus do not require distributions to be normalized. Finally, we show how to compute statistical Holder centroids with respect to those divergences and carry out center-based clustering toy experiments on a set of Gaussian distributions which demonstrate empirically that symmetrized Holder divergences outperform the symmetric Cauchy-Schwarz divergence.

  12. On Hölder Projective Divergences

    KAUST Repository

    Nielsen, Frank; Sun, Ke; Marchand-Maillet, Stephane

    2017-01-01

    We describe a framework to build distances by measuring the tightness of inequalities and introduce the notion of proper statistical divergences and improper pseudo-divergences. We then consider the Holder ordinary and reverse inequalities and present two novel classes of Holder divergences and pseudo-divergences that both encapsulate the special case of the Cauchy-Schwarz divergence. We report closed-form formulas for those statistical dissimilarities when considering distributions belonging to the same exponential family provided that the natural parameter space is a cone (e.g., multivariate Gaussians) or affine (e.g., categorical distributions). Those new classes of Holder distances are invariant to rescaling and thus do not require distributions to be normalized. Finally, we show how to compute statistical Holder centroids with respect to those divergences and carry out center-based clustering toy experiments on a set of Gaussian distributions which demonstrate empirically that symmetrized Holder divergences outperform the symmetric Cauchy-Schwarz divergence.

  13. Genetic Divergence in Sugarcane Genotypes

    OpenAIRE

    Tahir, Mohammad; Rahman, Hidayatur; Gul, Rahmani; Ali, Amjad; Khalid, Muhammad

    2012-01-01

    To assess genetic divergence of sugarcane germplasm, an experiment comprising 25 sugarcane genotypes was conducted at Sugar Crops Research Institute (SCRI), Mardan, Khyber Pakhtunkhwa, Pakistan, in quadruple lattice design during 2008-09. Among the 14 parameters evaluated, majority exhibited significant differences while some showed nonsignificant mean squares. The initial correlation matrix revealed medium to high correlations. Principal Component Analysis (PCA) showed that there were two pr...

  14. Computer recognition of divergences in Feynman graphs

    Energy Technology Data Exchange (ETDEWEB)

    Calmet, J

    1973-05-01

    The program described recognizes whether or not a graph is divergent. It determines the kind of the divergences found: vacuum polarizations, electron self energies and vertices. it does not consider infrared divergences. The programming language used is REDUCE. A LISP version is also available. The nature of the divergences and their counter terms was extensively used to write down this program, therefore it is limited to the case of quantum electrodynamics. (auth)

  15. Genetic divergence of tomato subsamples

    Directory of Open Access Journals (Sweden)

    André Pugnal Mattedi

    2014-02-01

    Full Text Available Understanding the genetic variability of a species is crucial for the progress of a genetic breeding program and requires characterization and evaluation of germplasm. This study aimed to characterize and evaluate 101 tomato subsamples of the Salad group (fresh market and two commercial controls, one of the Salad group (cv. Fanny and another of the Santa Cruz group (cv. Santa Clara. Four experiments were conducted in a randomized block design with three replications and five plants per plot. The joint analysis of variance was performed and characteristics with significant complex interaction between control and experiment were excluded. Subsequently, the multicollinearity diagnostic test was carried out and characteristics that contributed to severe multicollinearity were excluded. The relative importance of each characteristics for genetic divergence was calculated by the Singh's method (Singh, 1981, and the less important ones were excluded according to Garcia (1998. Results showed large genetic divergence among the subsamples for morphological, agronomic and organoleptic characteristics, indicating potential for genetic improvement. The characteristics total soluble solids, mean number of good fruits per plant, endocarp thickness, mean mass of marketable fruit per plant, total acidity, mean number of unmarketable fruit per plant, internode diameter, internode length, main stem thickness and leaf width contributed little to the genetic divergence between the subsamples and may be excluded in future studies.

  16. Increased genetic divergence between two closely related fir species in areas of range overlap

    Science.gov (United States)

    Wang, Jing; Abbott, Richard J; Ingvarsson, Pär K; Liu, Jianquan

    2014-01-01

    Because of introgressive hybridization, closely related species can be more similar to each other in areas of range overlap (parapatry or sympatry) than in areas where they are geographically isolated from each other (allopatry). Here, we report the reverse situation based on nuclear genetic divergence between two fir species, Abies chensiensis and Abies fargesii, in China, at sites where they are parapatric relative to where they are allopatric. We examined genetic divergence across 126 amplified fragment length polymorphism (AFLP) markers in a set of 172 individuals sampled from both allopatric and parapatric populations of the two species. Our analyses demonstrated that AFLP divergence was much greater between the species when comparisons were made between parapatric populations than between allopatric populations. We suggest that selection in parapatry may have largely contributed to this increased divergence. PMID:24772279

  17. Statistical inference based on divergence measures

    CERN Document Server

    Pardo, Leandro

    2005-01-01

    The idea of using functionals of Information Theory, such as entropies or divergences, in statistical inference is not new. However, in spite of the fact that divergence statistics have become a very good alternative to the classical likelihood ratio test and the Pearson-type statistic in discrete models, many statisticians remain unaware of this powerful approach.Statistical Inference Based on Divergence Measures explores classical problems of statistical inference, such as estimation and hypothesis testing, on the basis of measures of entropy and divergence. The first two chapters form an overview, from a statistical perspective, of the most important measures of entropy and divergence and study their properties. The author then examines the statistical analysis of discrete multivariate data with emphasis is on problems in contingency tables and loglinear models using phi-divergence test statistics as well as minimum phi-divergence estimators. The final chapter looks at testing in general populations, prese...

  18. Ultraviolet divergences and supersymmetric theories

    International Nuclear Information System (INIS)

    Sagnotti, A.

    1984-09-01

    This article is closely related to the one by Ferrara in these same Proceedings. It deals with what is perhaps the most fascinating property of supersymmetric theories, their improved ultraviolet behavior. My aim here is to present a survey of the state of the art as of August, 1984, and a somewhat more detailed discussion of the breakdown of the superspace power-counting beyond N = 2 superfields. A method is also described for simplifying divergence calculations that uses the locality of subtracted Feynman integrals. 74 references

  19. Ultraviolet divergences of Einstein gravity

    International Nuclear Information System (INIS)

    Goroff, M.H.

    1986-01-01

    The author discuss a two-loop calculation showing that the S matrix of Einstein's theory of gravity contains nonrenormalizable ultraviolet divergences in four dimension. The author discusses the calculation in both background field and normal field theory. The author describes a new method for dealing with ghost fields in gauge theories by combining them with suitable extensions of the gauge fields in higher dimensions. The author shows how using subtracted integrals in the calculation of higher loop graphs simplifies the calculation in the background field method by eliminating the need for mixed counterterms. Finally, the author makes some remarks about the implications of the result for supergravity theories

  20. Potentiel infectieux des sols de cultures de tomate (Lycopersicon esculentum Mill. sous abri et incidence de l'âge de repiquage sur la vigueur des plants vis-à-vis de Pythium sp. à Songon-Dabou en Côte d'Ivoire

    Directory of Open Access Journals (Sweden)

    Koné, D.

    2008-01-01

    Full Text Available Potentiel Infectious of Soils Fields of Tomato (Lycopersicon esculentum Mill. in Greenhouse and the Age Incidence Facing Pythium sp. on the Plants at Songon-Dabou in Ivory Coast. Songon-Dabou area represents one of the spheres activities of tomato in Ivory Coast. The production of tomato is strongly influenced by some of viruses, bacteria and soil born fungi. A study was conducted on the soils of different fields with three varieties of tomato (Caraïbo, Mongal and Tropimech to identify the most susceptible variety to soil born fungi at Songon-Dabou. By baiting with 20 days old seedlings, 4 genus fungi of Pythium, Fusarium, Sclerotium and Macrophomina have been isolated. Pythium sp. presented the greatest attack (32% while Macrophomina phaseoli was isolated for the first time on market gardening in Ivory Coast. Tomato plants have been inoculated by Pythium at different stages obtained from seedling to 25 days old nursery seedlings. That experiment was repeated three times. This work was conducted in greenhouse during 26 days after transplantation of the plants in the pots. These results confirm that Pythium sp. is a fungus of damping off (100% and that age of transplantation reduces the rate of mortality (less than 20%.

  1. Wetlands explain most in the genetic divergence pattern of Oncomelania hupensis.

    Science.gov (United States)

    Liang, Lu; Liu, Yang; Liao, Jishan; Gong, Peng

    2014-10-01

    Understanding the divergence patterns of hosts could shed lights on the prediction of their parasite transmission. No effort has been devoted to understand the drivers of genetic divergence pattern of Oncomelania hupensis, the only intermediate host of Schistosoma japonicum. Based on a compilation of two O. hupensis gene datasets covering a wide geographic range in China and an array of geographical distance and environmental dissimilarity metrics built from earth observation data and ecological niche modeling, we conducted causal modeling analysis via simple, partial Mantel test and local polynomial fitting to understand the interactions among isolation-by-distance, isolation-by-environment, and genetic divergence. We found that geography contributes more to genetic divergence than environmental isolation, and among all variables involved, wetland showed the strongest correlation with the genetic pairwise distances. These results suggested that in China, O. hupensis dispersal is strongly linked to the distribution of wetlands, and the current divergence pattern of both O. hupensis and schistosomiasis might be altered due to the changed wetland pattern with the accomplishment of the Three Gorges Dam and the South-to-North water transfer project. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Divergent thinking and constructing episodic simulations.

    Science.gov (United States)

    Addis, Donna Rose; Pan, Ling; Musicaro, Regina; Schacter, Daniel L

    2016-01-01

    Divergent thinking likely plays an important role in simulating autobiographical events. We investigated whether divergent thinking is differentially associated with the ability to construct detailed imagined future and imagined past events as opposed to recalling past events. We also examined whether age differences in divergent thinking might underlie the reduced episodic detail generated by older adults. The richness of episodic detail comprising autobiographical events in young and older adults was assessed using the Autobiographical Interview. Divergent thinking abilities were measured using the Alternative Uses Task. Divergent thinking was significantly associated with the amount of episodic detail for imagined future events. Moreover, while age was significantly associated with imagined episodic detail, this effect was strongly related to age-related changes in episodic retrieval rather than divergent thinking.

  3. The Immunoreactive Exo-1,3-β-Glucanase from the Pathogenic Oomycete Pythium insidiosum Is Temperature Regulated and Exhibits Glycoside Hydrolase Activity.

    Directory of Open Access Journals (Sweden)

    Angsana Keeratijarut

    Full Text Available The oomycete organism, Pythium insidiosum, is the etiologic agent of the life-threatening infectious disease called "pythiosis". Diagnosis and treatment of pythiosis is difficult and challenging. Novel methods for early diagnosis and effective treatment are urgently needed. Recently, we reported a 74-kDa immunodominant protein of P. insidiosum, which could be a diagnostic target, vaccine candidate, and virulence factor. The protein was identified as a putative exo-1,3-ß-glucanase (Exo1. This study reports on genetic, immunological, and biochemical characteristics of Exo1. The full-length exo1 coding sequence (2,229 bases was cloned. Phylogenetic analysis showed that exo1 is grouped with glucanase-encoding genes of other oomycetes, and is far different from glucanase-encoding genes of fungi. exo1 was up-regulated upon exposure to body temperature, and its gene product is predicted to contain BglC and X8 domains, which are involved in carbohydrate transport, binding, and metabolism. Based on its sequence, Exo1 belongs to the Glycoside Hydrolase family 5 (GH5. Exo1, expressed in E. coli, exhibited ß-glucanase and cellulase activities. Exo1 is a major intracellular immunoreactive protein that can trigger host immune responses during infection. Since GH5 enzyme-encoding genes are not present in human genomes, Exo1 could be a useful target for drug and vaccine development against this pathogen.

  4. Functional Analysis of the Trichoderma harzianum nox1 Gene, Encoding an NADPH Oxidase, Relates Production of Reactive Oxygen Species to Specific Biocontrol Activity against Pythium ultimum▿†

    Science.gov (United States)

    Montero-Barrientos, M.; Hermosa, R.; Cardoza, R. E.; Gutiérrez, S.; Monte, E.

    2011-01-01

    The synthesis of reactive oxygen species (ROS) is one of the first events following pathogenic interactions in eukaryotic cells, and NADPH oxidases are involved in the formation of such ROS. The nox1 gene of Trichoderma harzianum was cloned, and its role in antagonism against phytopathogens was analyzed in nox1-overexpressed transformants. The increased levels of nox1 expression in these transformants were accompanied by an increase in ROS production during their direct confrontation with Pythium ultimum. The transformants displayed an increased hydrolytic pattern, as determined by comparing protease, cellulase, and chitinase activities with those for the wild type. In confrontation assays against P. ultimum the nox1-overexpressed transformants were more effective than the wild type, but not in assays against Botrytis cinerea or Rhizoctonia solani. A transcriptomic analysis using a Trichoderma high-density oligonucleotide (HDO) microarray also showed that, compared to gene expression for the interaction of wild-type T. harzianum and P. ultimum, genes related to protease, cellulase, and chitinase activities were differentially upregulated in the interaction of a nox1-overexpressed transformant with this pathogen. Our results show that nox1 is involved in T. harzianum ROS production and antagonism against P. ultimum. PMID:21421791

  5. In vitro and in vivo susceptibility of two-drug and three-drug combinations of terbinafine, itraconazole, caspofungin, ibuprofen and fluvastatin against Pythium insidiosum.

    Science.gov (United States)

    Argenta, Juliana S; Alves, Sydney H; Silveira, Flávio; Maboni, Grazieli; Zanette, Régis A; Cavalheiro, Ayrton S; Pereira, Patrique L; Pereira, Daniela I B; Sallis, Elisa S V; Pötter, Luciana; Santurio, Janio M; Ferreiro, Laerte

    2012-05-25

    The present study investigated the in vitro inhibitory activity of terbinafine, itraconazole, caspofungin, fluvastatin and ibuprofen against 15 isolates of Pythium insidiosum in double and triple combinations and determined in vivo correlations using rabbits with experimental pythiosis. The minimal inhibitory concentration (MIC) was determined in accordance with the Clinical and Laboratory Standards Institute M 38-A2 protocol (2008), and the in vitro interactions were evaluated using a checkerboard microdilution method. For the in vivo study, 20 rabbits inoculated with P. insidiosum zoospores were divided into four groups: group 1 was treated with terbinafine and itraconazole; group 2 was treated with terbinafine, itraconazole and fluvastatin; group 3 was treated with terbinafine and caspofungin; and group 4 was the control group. Combinations of terbinafine with caspofungin or ibuprofen were synergistic for 47% of the isolates, and antagonism was not observed in any of the double combinations. The triple combinations were mostly indifferent, but synergism and antagonism were also observed. In the in vivo study, the histological aspect of the lesions was similar among the groups, but group 2 showed the lowest amount of hyphae and differed significantly from the other groups. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Volunteered Geographic Information in Wikipedia

    Science.gov (United States)

    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…

  7. Genetic divergence analysis in pumpkin

    International Nuclear Information System (INIS)

    Quamruzzaman, A.M.; Moniruzzaman, M.

    2013-01-01

    Genetic divergence among 18 punpkin genotypes was estimated using Mahalanohis's 1) statistic. Altogether lour clusters were formed where cluster I contained the highest number of genotypes (8) and cluster II contained the lowest (I). The highest intra-cluster distance was observed h.ir cluster I (0.83 I) and the lowest for clustcr IV (0.65 I). The highest inter-cluster distance was observed between cluster I and 11(24.346). Cluster II recorded the highest mean for fruit number/plant, TSS, fruit yield and niinitnuiii III cavity length and cavity diameter. Cluster III had the second highest mean for fruit diameter, fruit number/plant, individual unit weight, fruit yield and the fewest number of days to 1st Female flowering, earliness being a desirable trait. These crosses may produce new recombinants with desirable traits. (author)

  8. Divergence operator and related inequalities

    CERN Document Server

    Acosta, Gabriel

    2017-01-01

    This Brief is mainly devoted to two classical and related results: the existence of a right inverse of the divergence operator and the so-called Korn Inequalities. It is well known that both results are fundamental tools in the analysis of some classic differential equations, particularly in those arising in fluid dynamics and elasticity. Several connections between these two topics and improved Poincaré inequalities are extensively treated. From simple key ideas the book is growing smoothly in complexity. Beginning with the study of these problems on star-shaped domains the arguments are extended first to John domains and then to Hölder α domains where the need of weighted spaces arises naturally. In this fashion, the authors succeed in presenting in an unified and concise way several classic and recent developments in the field. These features certainly makes this Brief useful for students, post-graduate students, and researchers as well.

  9. Ramanujan summation of divergent series

    CERN Document Server

    Candelpergher, Bernard

    2017-01-01

    The aim of this monograph is to give a detailed exposition of the summation method that Ramanujan uses in Chapter VI of his second Notebook. This method, presented by Ramanujan as an application of the Euler-MacLaurin formula, is here extended using a difference equation in a space of analytic functions. This provides simple proofs of theorems on the summation of some divergent series. Several examples and applications are given. For numerical evaluation, a formula in terms of convergent series is provided by the use of Newton interpolation. The relation with other summation processes such as those of Borel and Euler is also studied. Finally, in the last chapter, a purely algebraic theory is developed that unifies all these summation processes. This monograph is aimed at graduate students and researchers who have a basic knowledge of analytic function theory.

  10. Beam divergence scaling in neutral beam injectors

    International Nuclear Information System (INIS)

    Holmes, A.J.T.

    1976-01-01

    One of the main considerations in the design of neutral beam injectors is to monimize the divergence of the primary ion beam and hence maximize the beam transport and minimize the input of thermal gas. Experimental measurements of the divergence of a cylindrical ion beam are presented and these measurements are used to analyze the major components of ion beam divergence, namely: space charge expansion, gas-ion scattering, emittance and optical aberrations. The implication of these divergence components in the design of a neutral beam injector system is discussed and a method of maximizing the beam current is described for a given area of source plasma

  11. Guises and disguises of quadratic divergences

    Energy Technology Data Exchange (ETDEWEB)

    Cherchiglia, A.L., E-mail: adriano@fisica.ufmg.br [Departamento de Física, ICEx, Universidade Federal de Minas Gerais, P.O. BOX 702, 30.161-970, Belo Horizonte, MG (Brazil); Vieira, A.R., E-mail: arvieira@fisica.ufmg.br [Departamento de Física, ICEx, Universidade Federal de Minas Gerais, P.O. BOX 702, 30.161-970, Belo Horizonte, MG (Brazil); Hiller, Brigitte, E-mail: brigitte@teor.fis.uc.pt [Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-516 Coimbra (Portugal); Baêta Scarpelli, A.P., E-mail: scarpelli.apbs@dpf.gov.br [Setor Técnico-Científico, Departamento de Polícia Federal, Rua Hugo D’Antola, 95 - Lapa, São Paulo (Brazil); Sampaio, Marcos, E-mail: marcos.sampaio@durham.ac.uk [Departamento de Física, ICEx, Universidade Federal de Minas Gerais, P.O. BOX 702, 30.161-970, Belo Horizonte, MG (Brazil); Centre for Particle Theory, Department of Mathematical Sciences, Durham University, South Road Durham DH1 3LE (United Kingdom)

    2014-12-15

    In this contribution, we present a new perspective on the control of quadratic divergences in quantum field theory, in general, and in the Higgs naturalness problem, in particular. Our discussion is essentially based on an approach where UV divergences are parameterized, after being reduced to basic divergent integrals (BDI) in one internal momentum, as functions of a cutoff and a renormalization group scale λ. We illustrate our proposal with well-known examples, such as the gluon vacuum self energy of QCD and the Higgs decay in two photons within this approach. We also discuss frameworks in effective low-energy QCD models, where quadratic divergences are indeed fundamental.

  12. Divergence Palsy due to Divalproex and Oxcarbazepine.

    Science.gov (United States)

    Bouffard, Marc Albert; Caplan, Louis R; Torun, Nurhan

    This case series is the first to describe divergence palsy as an adverse effect of antiepileptic drug use. Diplopia is a common adverse effect of antiepileptic drugs, but no explanatory motility deficit has ever been reported. We present 2 patients, 1 on oxcarbazepine and 1 on divalproex, each with a normal examination result between spells and divergency palsy when symptomatic. Discontinuation of the antiepileptic medication led to resolution of the episodes in both cases. Rechallenge with the offending agent after washout in one patient resulted in recurrence of diplopia and divergence palsy, both resolving after subsequent withdrawal of the antiepileptic. Antiepileptic drugs may cause divergence palsy.

  13. Geographic Ontologies, Gazetteers and Multilingualism

    Directory of Open Access Journals (Sweden)

    Robert Laurini

    2015-01-01

    Full Text Available Different languages imply different visions of space, so that terminologies are different in geographic ontologies. In addition to their geometric shapes, geographic features have names, sometimes different in diverse languages. In addition, the role of gazetteers, as dictionaries of place names (toponyms, is to maintain relations between place names and location. The scope of geographic information retrieval is to search for geographic information not against a database, but against the whole Internet: but the Internet stores information in different languages, and it is of paramount importance not to remain stuck to a unique language. In this paper, our first step is to clarify the links between geographic objects as computer representations of geographic features, ontologies and gazetteers designed in various languages. Then, we propose some inference rules for matching not only types, but also relations in geographic ontologies with the assistance of gazetteers.

  14. k-Means Clustering with Hölder Divergences

    KAUST Repository

    Nielsen, Frank; Sun, Ke; Marchand-Maillet, Sté phane

    2017-01-01

    We introduced two novel classes of Hölder divergences and Hölder pseudo-divergences that are both invariant to rescaling, and that both encapsulate the Cauchy-Schwarz divergence and the skew Bhattacharyya divergences. We review the elementary concepts of those parametric divergences, and perform a clustering analysis on two synthetic datasets. It is shown experimentally that the symmetrized Hölder divergences consistently outperform significantly the Cauchy-Schwarz divergence in clustering tasks.

  15. k-Means Clustering with Hölder Divergences

    KAUST Repository

    Nielsen, Frank

    2017-10-24

    We introduced two novel classes of Hölder divergences and Hölder pseudo-divergences that are both invariant to rescaling, and that both encapsulate the Cauchy-Schwarz divergence and the skew Bhattacharyya divergences. We review the elementary concepts of those parametric divergences, and perform a clustering analysis on two synthetic datasets. It is shown experimentally that the symmetrized Hölder divergences consistently outperform significantly the Cauchy-Schwarz divergence in clustering tasks.

  16. Lexicographic presentation of grammatical divergence in Sesotho ...

    African Journals Online (AJOL)

    Relying on existing insights from the field of theoretical lexicography this article gives an innovative application to the relation of divergence by introducing the notion of grammatical divergence. In bilingual dictionaries with English and Sesotho sa Leboa as language pair lexicographers are confronted with a real challenge ...

  17. Divergent Thinking and Age-Related Changes

    Science.gov (United States)

    Palmiero, Massimiliano; Di Giacomo, Dina; Passafiume, Domenico

    2014-01-01

    Aging can affect cognition in different ways. The extent to which aging affects divergent thinking is unclear. In this study, younger and older adults were compared at the performance on the Torrance Test of Creative Thinking in visual and verbal form. Results showed that older adults can think divergently as younger participants, although they…

  18. Using geographic information systems

    International Nuclear Information System (INIS)

    Winsor, R.W.

    1997-01-01

    A true Geographic Information System (GIS) is a computer mapping system with spatial analysis ability and cartographic accuracy that will offer many different projections. GIS has evolved to become an everyday tool for a wide range of users including oil companies, worldwide. Other systems are designed to allow oil and gas companies to keep their upstream data in the same format. Among these are the Public Petroleum Data Model developed by Gulf Canada, Digitech and Applied Terravision Systems of Calgary, the system developed and marketed by the Petrotechnical Open Software Corporation in the United States, and the Mercury projects by IBM. These have been developed in an effort to define an industry standard. The advantages and disadvantages of open and closed systems were discussed. Factors to consider when choosing a GIS system such as overall performance, area of use and query complexity, were reviewed. 3 figs

  19. Metabolic Rate and Climatic Fluctuations Shape Continental Wide Pattern of Genetic Divergence and Biodiversity in Fishes

    Science.gov (United States)

    April, Julien; Hanner, Robert H.; Mayden, Richard L.; Bernatchez, Louis

    2013-01-01

    Taxonomically exhaustive and continent wide patterns of genetic divergence within and between species have rarely been described and the underlying evolutionary causes shaping biodiversity distribution remain contentious. Here, we show that geographic patterns of intraspecific and interspecific genetic divergence among nearly all of the North American freshwater fish species (>750 species) support a dual role involving both the late Pliocene-Pleistocene climatic fluctuations and metabolic rate in determining latitudinal gradients of genetic divergence and very likely influencing speciation rates. Results indicate that the recurrent glacial cycles caused global reduction in intraspecific diversity, interspecific genetic divergence, and species richness at higher latitudes. At the opposite, longer geographic isolation, higher metabolic rate increasing substitution rate and possibly the rapid accumulation of genetic incompatibilities, led to an increasing biodiversity towards lower latitudes. This indicates that both intrinsic and extrinsic factors similarly affect micro and macro evolutionary processes shaping global patterns of biodiversity distribution. These results also indicate that factors favouring allopatric speciation are the main drivers underlying the diversification of North American freshwater fishes. PMID:23922969

  20. Little Divergence Among Mitochondrial Lineages of Prochilodus (Teleostei, Characiformes

    Directory of Open Access Journals (Sweden)

    Bruno F. Melo

    2018-04-01

    Full Text Available Evidence that migration prevents population structure among Neotropical characiform fishes has been reported recently but the effects upon species diversification remain unclear. Migratory species of Prochilodus have complex species boundaries and intrincate taxonomy representing a good model to address such questions. Here, we analyzed 147 specimens through barcode sequences covering all species of Prochilodus across a broad geographic area of South America. Species delimitation and population genetic methods revealed very little genetic divergence among mitochondrial lineages suggesting that extensive gene flow resulted likely from the highly migratory behavior, natural hybridization or recent radiation prevent accumulation of genetic disparity among lineages. Our results clearly delimit eight genetic lineages in which four of them contain a single species and four contain more than one morphologically problematic taxon including a trans-Andean species pair and species of the P. nigricans group. Information about biogeographic distribution of haplotypes presented here might contribute to further research on the population genetics and taxonomy of Prochilodus.

  1. GEOGRAPHIC NAMES INFORMATION SYSTEM (GNIS) ...

    Science.gov (United States)

    The Geographic Names Information System (GNIS), developed by the U.S. Geological Survey in cooperation with the U.S. Board on Geographic Names (BGN), contains information about physical and cultural geographic features in the United States and associated areas, both current and historical, but not including roads and highways. The database also contains geographic names in Antarctica. The database holds the Federally recognized name of each feature and defines the location of the feature by state, county, USGS topographic map, and geographic coordinates. Other feature attributes include names or spellings other than the official name, feature designations, feature class, historical and descriptive information, and for some categories of features the geometric boundaries. The database assigns a unique feature identifier, a random number, that is a key for accessing, integrating, or reconciling GNIS data with other data sets. The GNIS is our Nation's official repository of domestic geographic feature names information.

  2. Genetic divergence of common bean cultivars.

    Science.gov (United States)

    Veloso, J S; Silva, W; Pinheiro, L R; Dos Santos, J B; Fonseca, N S; Euzebio, M P

    2015-09-22

    The aim of this study was to evaluate genetic divergence in the 'Carioca' (beige with brown stripes) common bean cultivar used by different institutions and in 16 other common bean cultivars used in the Rede Cooperativa de Pesquisa de Feijão (Cooperative Network of Common Bean Research), by using simple sequence repeats associated with agronomic traits that are highly distributed in the common bean genome. We evaluated 22 polymorphic loci using bulks containing DNA from 30 plants. There was genetic divergence among the Carioca cultivar provided by the institutions. Nevertheless, there was lower divergence among them than among the other cultivars. The cultivar used by Instituto Agronômico do Paraná was the most divergent in relation to the Carioca samples. The least divergence was observed among the samples used by Universidade Federal de Lavras and by Embrapa Arroz e Feijão. Of all the cultivars, 'CNFP 10104' and 'BRSMG Realce' showed the greatest dissimilarity. The cultivars were separated in two groups of greatest similarity using the Structure software. Genetic variation among cultivars was greater than the variation within or between the groups formed. This fact, together with the high estimate of heterozygosity observed and the genetic divergence of the samples of the Carioca cultivar in relation to the original provided by Instituto Agronômico de Campinas, indicates a mixture of cultivars. The high divergence among cultivars provides potential for the utilization of this genetic variability in plant breeding.

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

    Science.gov (United States)

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

    2016-05-01

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

  4. The estimation of genetic divergence

    Science.gov (United States)

    Holmquist, R.; Conroy, T.

    1981-01-01

    Consideration is given to the criticism of Nei and Tateno (1978) of the REH (random evolutionary hits) theory of genetic divergence in nucleic acids and proteins, and to their proposed alternative estimator of total fixed mutations designated X2. It is argued that the assumption of nonuniform amino acid or nucleotide substitution will necessarily increase REH estimates relative to those made for a model where each locus has an equal likelihood of fixing mutations, thus the resulting value will not be an overestimation. The relative values of X2 and measures calculated on the basis of the PAM and REH theories for the number of nucleotide substitutions necessary to explain a given number of observed amino acid differences between two homologous proteins are compared, and the smaller values of X2 are attributed to (1) a mathematical model based on the incorrect assumption that an entire structural gene is free to fix mutations and (2) the assumptions of different numbers of variable codons for the X2 and REH calculations. Results of a repeat of the computer simulations of Nei and Tateno are presented which, in contrast to the original results, confirm the REH theory. It is pointed out that while a negative correlation is observed between estimations of the fixation intensity per varion and the number of varions for a given pair of sequences, the correlation between the two fixation intensities and varion numbers of two different pairs of sequences need not be negative. Finally, REH theory is used to resolve a paradox concerning the high rate of covarion turnover and the nature of general function sites as permanent covarions.

  5. Verbal and visual divergent thinking in aging.

    Science.gov (United States)

    Palmiero, Massimiliano; Nori, Raffaella; Piccardi, Laura

    2017-04-01

    According to the peak and decline model divergent thinking declines at a specific age (in or after middle age). However, if divergent thinking declines steadily in aging still has to be clarified. In order to explore the age-related changes in verbal and visual divergent thinking, in the present study a sample of 159 participants was divided in five age groups: young adults (18-35 years), middle-aged adults (36-55), young old (56-74), old (75-85) and the oldest-old (86-98). Two divergent thinking tasks were administered: the alternative uses for cardboard boxes, aimed at assessing verbal ideational fluency, flexibility and originality; the completion drawing task, aimed at assessing visual ideational fluency, flexibility and originality. Results showed that after peaking in the young adult group (20-35 years) all components of verbal and visual divergent thinking stabilized in the middle-aged adult group (36-55 years) and then started declining in the young old group (56-75). Interestingly, all components were found to be preserved after declining. Yet, verbal and visual divergent thinking were found at the same extent across age groups, with the exception of visual ideational fluency, that was higher in the young old group, the old group and the oldest-old group than verbal ideational fluency. These results support the idea that divergent thinking does not decline steadily in the elderly. Given that older people can preserve to some extent verbal and visual divergent thinking, these findings have important implications for active aging, that is, divergent thinking might be fostered in aging in order to prevent the cognitive decline.

  6. Coloring geographical threshold graphs

    Energy Technology Data Exchange (ETDEWEB)

    Bradonjic, Milan [Los Alamos National Laboratory; Percus, Allon [Los Alamos National Laboratory; Muller, Tobias [EINDHOVEN UNIV. OF TECH

    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.

  7. Development of IgY antibodies in chickens and IgG in rabbits immunized against proteins of Pythium insidiosum isolated from horses in the state of Rio de Janeiro Desenvolvimento de Anticorpos IgY em galinhas e IgG em coelhos imunizados contra proteínas de Pythium insidiosum isolado de equinos no Estado do Rio de Janeiro, Brasil

    Directory of Open Access Journals (Sweden)

    Maria Fabíola Nunes Rangel

    2010-01-01

    Full Text Available Pythiosis is caused by Pythium insidiosum and the occurrence of disease in horses was described in the North and Northwest State of Rio de Janeiro, Brazil. The disease was described in cattle, sheep, humans, and horses in different states and regions across the country. This paper describes the development of IgY and IgG polyclonal antibodies, in chicken and rabbits, respectively against proteins extracted from kunkers and hyphae of P. insidiosum from affected horses. The proteins were recognized by chicken, rabbit and horse antibodies by immunodiffusion and Western blot against majority bands of 27 and 43 KDa, and titrated by ELISA. The antibodies IgY developed by the first time against Brazilian strains of P. insidiosum may represent a valuable tool in the detection of antigens of the pathogen and contribute to further studies aimed at immunotherapy and knowledge about this disease in endemic areas in Rio de Janeiro and in Brazil.Pitiose é causada por Pythium insidiosum e a doença foi descrita em equinos no Norte e Noroeste do Estado do Rio de Janeiro, Brasil. A doença foi descrita em bovinos, ovelhas, humanos e cavalos em diferentes estados e regiões do país. Este trabalho descreve o desenvolvimento de anticorpos policlonais, IgY e IgG, em galinha e coelho, respectivamente, contra proteínas extraídas de kunkers e hifas de P. insidiosum de cavalos doentes. As proteínas foram reconhecidas por anticorpos de galinha, coelho e cavalos contra as bandas majoritárias de 27 e 34 KDa em imunodifusão e Western blot tituladas por ELISA. Os anticorpos IgY desenvolvidos pela primeira vez contra cepas brasileiras de P. insidiosum podem representar um valioso instrumento na detecção de antígenos de patógenos e contribuem para novos estudos baseados na imunoterapia e no entendimento sobre esta doença em áreas endêmicas no Rio de Janeiro e em todo o país.

  8. Two New Measures of Fuzzy Divergence and Their Properties

    Directory of Open Access Journals (Sweden)

    Om Parkash

    2006-06-01

    Full Text Available Several measures of directed divergence and their corresponding measures of fuzzy divergence are available in the exiting literature. Two new measures of fuzzy divergence have been developed and their desirable properties have been discussed.

  9. The impact of selection, gene flow and demographic history on heterogeneous genomic divergence: three-spine sticklebacks in divergent environments.

    Science.gov (United States)

    Ferchaud, Anne-Laure; Hansen, Michael M

    2016-01-01

    Heterogeneous genomic divergence between populations may reflect selection, but should also be seen in conjunction with gene flow and drift, particularly population bottlenecks. Marine and freshwater three-spine stickleback (Gasterosteus aculeatus) populations often exhibit different lateral armour plate morphs. Moreover, strikingly parallel genomic footprints across different marine-freshwater population pairs are interpreted as parallel evolution and gene reuse. Nevertheless, in some geographic regions like the North Sea and Baltic Sea, different patterns are observed. Freshwater populations in coastal regions are often dominated by marine morphs, suggesting that gene flow overwhelms selection, and genomic parallelism may also be less pronounced. We used RAD sequencing for analysing 28 888 SNPs in two marine and seven freshwater populations in Denmark, Europe. Freshwater populations represented a variety of environments: river populations accessible to gene flow from marine sticklebacks and large and small isolated lakes with and without fish predators. Sticklebacks in an accessible river environment showed minimal morphological and genomewide divergence from marine populations, supporting the hypothesis of gene flow overriding selection. Allele frequency spectra suggested bottlenecks in all freshwater populations, and particularly two small lake populations. However, genomic footprints ascribed to selection could nevertheless be identified. No genomic regions were consistent freshwater-marine outliers, and parallelism was much lower than in other comparable studies. Two genomic regions previously described to be under divergent selection in freshwater and marine populations were outliers between different freshwater populations. We ascribe these patterns to stronger environmental heterogeneity among freshwater populations in our study as compared to most other studies, although the demographic history involving bottlenecks should also be considered in the

  10. Adaptive divergence with gene flow in incipient speciation of Miscanthus floridulus / sinensis complex (Poaceae)

    KAUST Repository

    Huang, Chao-Li; Ho, Chuan-Wen; Chiang, Yu-Chung; Shigemoto, Yasumasa; Hsu, Tsai-Wen; Hwang, Chi-Chuan; Ge, Xue-Jun; Chen, Charles; Wu, Tai-Han; Chou, Chang-Hung; Huang, Hao-Jen; Gojobori, Takashi; Osada, Naoki; Chiang, Tzen-Yuh

    2014-01-01

    Young incipient species provide ideal materials for untangling the process of ecological speciation in the presence of gene flow. The Miscanthus floridulus/sinensis complex exhibits diverse phenotypic and ecological differences despite recent divergence (approximately 1.59million years ago). To elucidate the process of genetic differentiation during early stages of ecological speciation, we analyzed genomic divergence in the Miscanthus complex using 72 randomly selected genes from a newly assembled transcriptome. In this study, rampant gene flow was detected between species, estimated as M=3.36x10(-9) to 1.20x10(-6), resulting in contradicting phylogenies across loci. Nevertheless, beast analyses revealed the species identity and the effects of extrinsic cohesive forces that counteracted the non-stop introgression. As expected, early in speciation with gene flow, only 3-13 loci were highly diverged; two to five outliers (approximately 2.78-6.94% of the genome) were characterized by strong linkage disequilibrium, and asymmetrically distributed among ecotypes, indicating footprints of diversifying selection. In conclusion, ecological speciation of incipient species of Miscanthus probably followed the parapatric model, whereas allopatric speciation cannot be completely ruled out, especially between the geographically isolated northern and southern M.sinensis, for which no significant gene flow across oceanic barriers was detected. Divergence between local ecotypes in early-stage speciation began at a few genomic regions under the influence of natural selection and divergence hitchhiking that overcame gene flow.

  11. Evidence for Divergent Evolution of Growth Temperature Preference in Sympatric Saccharomyces Species

    Science.gov (United States)

    Gonçalves, Paula; Valério, Elisabete; Correia, Cláudia; de Almeida, João M. G. C. F.; Sampaio, José Paulo

    2011-01-01

    The genus Saccharomyces currently includes eight species in addition to the model yeast Saccharomyces cerevisiae, most of which can be consistently isolated from tree bark and soil. We recently found sympatric pairs of Saccharomyces species, composed of one cryotolerant and one thermotolerant species in oak bark samples of various geographic origins. In order to contribute to explain the occurrence in sympatry of Saccharomyces species, we screened Saccharomyces genomic data for protein divergence that might be correlated to distinct growth temperature preferences of the species, using the dN/dS ratio as a measure of protein evolution rates and pair-wise species comparisons. In addition to proteins previously implicated in growth at suboptimal temperatures, we found that glycolytic enzymes were among the proteins exhibiting higher than expected divergence when one cryotolerant and one thermotolerant species are compared. By measuring glycolytic fluxes and glycolytic enzymatic activities in different species and at different temperatures, we subsequently show that the unusual divergence of glycolytic genes may be related to divergent evolution of the glycolytic pathway aligning its performance to the growth temperature profiles of the different species. In general, our results support the view that growth temperature preference is a trait that may have undergone divergent selection in the course of ecological speciation in Saccharomyces. PMID:21674061

  12. Adaptive divergence with gene flow in incipient speciation of Miscanthus floridulus / sinensis complex (Poaceae)

    KAUST Repository

    Huang, Chao-Li

    2014-11-11

    Young incipient species provide ideal materials for untangling the process of ecological speciation in the presence of gene flow. The Miscanthus floridulus/sinensis complex exhibits diverse phenotypic and ecological differences despite recent divergence (approximately 1.59million years ago). To elucidate the process of genetic differentiation during early stages of ecological speciation, we analyzed genomic divergence in the Miscanthus complex using 72 randomly selected genes from a newly assembled transcriptome. In this study, rampant gene flow was detected between species, estimated as M=3.36x10(-9) to 1.20x10(-6), resulting in contradicting phylogenies across loci. Nevertheless, beast analyses revealed the species identity and the effects of extrinsic cohesive forces that counteracted the non-stop introgression. As expected, early in speciation with gene flow, only 3-13 loci were highly diverged; two to five outliers (approximately 2.78-6.94% of the genome) were characterized by strong linkage disequilibrium, and asymmetrically distributed among ecotypes, indicating footprints of diversifying selection. In conclusion, ecological speciation of incipient species of Miscanthus probably followed the parapatric model, whereas allopatric speciation cannot be completely ruled out, especially between the geographically isolated northern and southern M.sinensis, for which no significant gene flow across oceanic barriers was detected. Divergence between local ecotypes in early-stage speciation began at a few genomic regions under the influence of natural selection and divergence hitchhiking that overcame gene flow.

  13. Controle biológico da podridão radicular (Pythium aphanidermatum e promoção de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03 em alface hidropônica

    Directory of Open Access Journals (Sweden)

    Élida Barbosa Corrêa

    2010-12-01

    Full Text Available Podridões radiculares causadas por espécies de Pythium são um importante problema em cultivos hidropônicos. Sintomas de subdesenvolvimento são observados nas plantas parasitadas pelo patógeno, sendo muitas vezes não diagnosticados pelo produtor. O objetivo do trabalho foi avaliar o controle biológico da podridão radicular causada por Pythium aphanidermatum e a promoção de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03, reconhecidos agentes de controle biológico de doenças de plantas. A inoculação das plantas com P. aphanidermatum ocasionou o subdesenvolvimento, sendo essa diminuição de 20%. A adição dos agentes de biocontrole na solução nutritiva teve um efeito positivo no aumento da massa (6% a 13%, no número de folhas (4% a 7% e no teor de clorofila (3% das plantas de alface. Entretanto, maiores estudos devem ser realizados para melhorar a capacidade de controle da doença e de promoção de crescimento pelos agentes de biocontrole estudados no cultivo de alface hidropônica.

  14. Solarização do solo e incorporação de fontes de matéria orgânica no controle de Pythium spp.

    Directory of Open Access Journals (Sweden)

    Ghini Raquel

    2002-01-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da solarização do solo, associada à incorporação de lodo de esgoto, cama-de-frango e casca de Pinus, no controle de Pythium spp. Foram conduzidos dois ensaios, um em área cultivada comercialmente com crisântemo e outro em área artificialmente infestada com Pythium spp. em cultivo de pepino. A adição de cama-de-frango induziu a supressividade do solo ao patógeno, visto que resultou em maiores temperaturas no solo solarizado, aumento na condutividade elétrica e maior atividade microbiana do solo, avaliada pela hidrólise de diacetato de fluoresceína e desprendimento de CO2. Por outro lado, o lodo de esgoto e a casca de Pinus não induziram a supressividade ao patógeno. A solarização não teve efeito no crescimento da parte aérea e no peso de matéria fresca de raízes de plantas de crisântemo, mas teve efeito significativo no controle do patógeno no ensaio conduzido com pepino.

  15. Determinants of Dentists' Geographic Distribution.

    Science.gov (United States)

    Beazoglou, Tryfon J.; And Others

    1992-01-01

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

  16. Treatment of divergent expansions in scattering theory

    International Nuclear Information System (INIS)

    Gersten, A.; Malin, S.

    1978-01-01

    One of the biggest obstacles in applying quantum field theory to realistic scattering problems are the divergencies of pertubation expansions for large coupling constants and the divergencies of partial wave expansions for massless particles exchanges. There exist, however, methods of summation of the divergent expansions which can lead to significant application in physics. In this paper we treat the problem of summing such expansions using three methods: (i) a generalization of the Pade approximation to the multivariable case. The suggested definition is unique and preserves unitarity. (ii) The summation of divergent partial waves for arbitrary spins. (iii) A successful application of a series inversion to the 3 P 1 nucleon-nucleon phase shift up to 200 MeV. (orig./WL) [de

  17. Divergence and convergence in nutrition science

    NARCIS (Netherlands)

    Penders, Bart; Spruit, Shannon L.; Sikkema, Jan; Maat, Jan; Schuurbiers, Daan

    2015-01-01

    Nutrigenomics diverged from mainstream nutrition science, ideologically, instrumentally and culturally, due to the establishment of a protective niche. That protection is fading. This article chronicles a case in which convergence between nutrigenomics and nutrition science is pursued. Here we

  18. Constrained body shape among highly genetically divergent allopatric lineages of the supralittoral isopod Ligia occidentalis (Oniscidea).

    Science.gov (United States)

    Santamaria, Carlos A; Mateos, Mariana; DeWitt, Thomas J; Hurtado, Luis A

    2016-03-01

    Multiple highly divergent lineages have been identified within Ligia occidentalis sensu lato, a rocky supralittoral isopod distributed along a ~3000 km latitudinal gradient that encompasses several proposed marine biogeographic provinces and ecoregions in the eastern Pacific. Highly divergent lineages have nonoverlapping geographic distributions, with distributional limits that generally correspond with sharp environmental changes. Crossbreeding experiments suggest postmating reproductive barriers exist among some of them, and surveys of mitochondrial and nuclear gene markers do not show evidence of hybridization. Populations are highly isolated, some of which appear to be very small; thus, the effects of drift are expected to reduce the efficiency of selection. Large genetic divergences among lineages, marked environmental differences in their ranges, reproductive isolation, and/or high isolation of populations may have resulted in morphological differences in L. occidentalis, not detected yet by traditional taxonomy. We used landmark-based geometric morphometric analyses to test for differences in body shape among highly divergent lineages of L. occidentalis, and among populations within these lineages. We analyzed a total of 492 individuals from 53 coastal localities from the southern California Bight to Central Mexico, including the Gulf of California. We conducted discriminant function analyses (DFAs) on body shape morphometrics to assess morphological variation among genetically differentiated lineages and their populations. We also tested for associations between phylogeny and morphological variation, and whether genetic divergence is correlated to multivariate morphological divergence. We detected significant differences in body shape among highly divergent lineages, and among populations within these lineages. Nonetheless, neither lineages nor populations can be discriminated on the basis of body shape, because correct classification rates of cross

  19. Decoding divergent series in nonparaxial optics.

    Science.gov (United States)

    Borghi, Riccardo; Gori, Franco; Guattari, Giorgio; Santarsiero, Massimo

    2011-03-15

    A theoretical analysis aimed at investigating the divergent character of perturbative series involved in the study of free-space nonparaxial propagation of vectorial optical beams is proposed. Our analysis predicts a factorial divergence for such series and provides a theoretical framework within which the results of recently published numerical experiments concerning nonparaxial propagation of vectorial Gaussian beams find a meaningful interpretation in terms of the decoding operated on such series by the Weniger transformation.

  20. Collinearity, convergence and cancelling infrared divergences

    International Nuclear Information System (INIS)

    Lavelle, Martin; McMullan, David

    2006-01-01

    The Lee-Nauenberg theorem is a fundamental quantum mechanical result which provides the standard theoretical response to the problem of collinear and infrared divergences. Its argument, that the divergences due to massless charged particles can be removed by summing over degenerate states, has been successfully applied to systems with final state degeneracies such as LEP processes. If there are massless particles in both the initial and final states, as will be the case at the LHC, the theorem requires the incorporation of disconnected diagrams which produce connected interference effects at the level of the cross-section. However, this aspect of the theory has never been fully tested in the calculation of a cross-section. We show through explicit examples that in such cases the theorem introduces a divergent series of diagrams and hence fails to cancel the infrared divergences. It is also demonstrated that the widespread practice of treating soft infrared divergences by the Bloch-Nordsieck method and handling collinear divergences by the Lee-Nauenberg method is not consistent in such cases

  1. Geographic information systems: introduction.

    Science.gov (United States)

    Calistri, Paolo; Conte, Annamaria; Freier, Jerome E; Ward, Michael P

    2007-01-01

    The recent exponential growth of the science and technology of geographic information systems (GIS) has made a tremendous contribution to epidemiological analysis and has led to the development of new powerful tools for the surveillance of animal diseases. GIS, spatial analysis and remote sensing provide valuable methods to collect and manage information for epidemiological surveys. Spatial patterns and trends of disease can be correlated with climatic and environmental information, thus contributing to a better understanding of the links between disease processes and explanatory spatial variables. Until recently, these tools were underexploited in the field of veterinary public health, due to the prohibitive cost of hardware and the complexity of GIS software that required a high level of expertise. The revolutionary developments in computer performance of the last decade have not only reduced the costs of equipment but have made available easy-to-use Web-based software which in turn have meant that GIS are more widely accessible by veterinary services at all levels. At the same time, the increased awareness of the possibilities offered by these tools has created new opportunities for decision-makers to enhance their planning, analysis and monitoring capabilities. These technologies offer a new way of sharing and accessing spatial and non-spatial data across groups and institutions. The series of papers included in this compilation aim to: - define the state of the art in the use of GIS in veterinary activities - identify priority needs in the development of new GIS tools at the international level for the surveillance of animal diseases and zoonoses - define practical proposals for their implementation. The topics addressed are presented in the following order in this book: - importance of GIS for the monitoring of animal diseases and zoonoses - GIS application in surveillance activities - spatial analysis in veterinary epidemiology - data collection and remote

  2. Northern Bobwhite (Colinus virginianus Mitochondrial Population Genomics Reveals Structure, Divergence, and Evidence for Heteroplasmy.

    Directory of Open Access Journals (Sweden)

    Yvette A Halley

    Full Text Available Herein, we evaluated the concordance of population inferences and conclusions resulting from the analysis of short mitochondrial fragments (i.e., partial or complete D-Loop nucleotide sequences versus complete mitogenome sequences for 53 bobwhites representing six ecoregions across TX and OK (USA. Median joining (MJ haplotype networks demonstrated that analyses performed using small mitochondrial fragments were insufficient for estimating the true (i.e., complete mitogenome haplotype structure, corresponding levels of divergence, and maternal population history of our samples. Notably, discordant demographic inferences were observed when mismatch distributions of partial (i.e., partial D-Loop versus complete mitogenome sequences were compared, with the reduction in mitochondrial genomic information content observed to encourage spurious inferences in our samples. A probabilistic approach to variant prediction for the complete bobwhite mitogenomes revealed 344 segregating sites corresponding to 347 total mutations, including 49 putative nonsynonymous single nucleotide variants (SNVs distributed across 12 protein coding genes. Evidence of gross heteroplasmy was observed for 13 bobwhites, with 10 of the 13 heteroplasmies involving one moderate to high frequency SNV. Haplotype network and phylogenetic analyses for the complete bobwhite mitogenome sequences revealed two divergent maternal lineages (dXY = 0.00731; FST = 0.849; P < 0.05, thereby supporting the potential for two putative subspecies. However, the diverged lineage (n = 103 variants almost exclusively involved bobwhites geographically classified as Colinus virginianus texanus, which is discordant with the expectations of previous geographic subspecies designations. Tests of adaptive evolution for functional divergence (MKT, frequency distribution tests (D, FS and phylogenetic analyses (RAxML provide no evidence for positive selection or hybridization with the sympatric scaled quail

  3. NEPR Geographic Zone Map 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This geographic zone map was created by interpreting satellite and aerial imagery, seafloor topography (bathymetry model), and the new NEPR Benthic Habitat Map...

  4. Ecoscapes: Geographical Patternings of Relations

    Directory of Open Access Journals (Sweden)

    Aimar Ventsel

    2012-06-01

    Full Text Available Book review of the publication Ecoscapes: Geographical Patternings of Relations. Edited by Gary Backhaus and John Murungi. Lanham, Boulder, New York, Toronto, Oxford, Lexington Books, 2006, xxxiii+241 pp.

  5. Ecoscapes: Geographical Patternings of Relations

    Directory of Open Access Journals (Sweden)

    Aimar Ventsel

    2013-01-01

    Full Text Available Book review of the publication Ecoscapes: Geographical Patternings of Relations. Edited by Gary Backhaus and John Murungi. Lanham, Boulder, New York, Toronto, Oxford, Lexington Books, 2006, xxxiii+241 pp.

  6. Properties of classical and quantum Jensen-Shannon divergence

    NARCIS (Netherlands)

    J. Briët (Jop); P. Harremoës (Peter)

    2009-01-01

    htmlabstractJensen-Shannon divergence (JD) is a symmetrized and smoothed version of the most important divergence measure of information theory, Kullback divergence. As opposed to Kullback divergence it determines in a very direct way a metric; indeed, it is the square of a metric. We consider a

  7. Beam Angular Divergence Effects in Ion Implantation

    International Nuclear Information System (INIS)

    Horsky, T. N.; Hahto, S. K.; Bilbrough, D. G.; Jacobson, D. C.; Krull, W. A.; Goldberg, R. D.; Current, M. I.; Hamamoto, N.; Umisedo, S.

    2008-01-01

    An important difference between monomer ion beams and heavy molecular beams is a significant reduction in beam angular divergence and increased on-wafer angular accuracy for molecular beams. This advantage in beam quality stems from a reduction in space-charge effects within the beam. Such improved angular accuracy has been shown to have a significant impact on the quality and yield of transistor devices [1,12]. In this study, B 18 H x + beam current and angular divergence data collected on a hybrid scanned beam line that magnetically scans the beam across the wafer is presented. Angular divergence is kept below 0.5 deg from an effective boron energy of 200 eV to 3000 eV. Under these conditions, the beam current is shown analytically to be limited by space charge below about 1 keV, but by the matching of the beam emittance to the acceptance of the beam line above 1 keV. In addition, results of a beam transport model which includes variable space charge compensation are presented, in which a drift mode B 18 H x + beam is compared to an otherwise identical boron beam after deceleration. Deceleration is shown to introduce significant space-charge blow up resulting in a large on-wafer angular divergence. The divergence effects introduced by wafer charging are also discussed.

  8. Ion divergence in magnetically insulated diodes

    International Nuclear Information System (INIS)

    Slutz, S.A.; Lemke, R.W.; Pointon, T.D.; Desjarlais, M.P.; Johnson, D.J.; Mehlhorn, T.A.; Filuk, A.; Bailey, J.

    1995-01-01

    Magnetically insulated ion diodes are being developed to drive inertial confinement fusion. Ion beam microdivergence must be reduced to achieve the very high beam intensities required to achieve this goal. Three-dimensional particle-in-cell simulations indicate that instability induced fluctuations can produce significant ion divergence during acceleration. These simulations exhibit a fast growing mode early in time, which has been identified as the diocotron instability. The divergence generated by this mode is modest due to the relatively high frequency (>1GHz). Later, a low-frequency low-phase-velocity instability develops. This instability couples effectively to the ions, since the frequency is approximately the reciprocal of the ion transit time, and can generate unacceptably large ion divergences (>30 mrad). Linear stability theory reveals that this mode requires perturbations parallel to the applied magnetic field and is related to the modified two stream instability. Measurements of ion density fluctuations and energy-momentum correlations have confirmed that instabilities develop in ion diodes and contribute to the ion divergence. In addition, spectroscopic measurements indicate that the ions have a significant transverse temperature very close to the emission surface. Passive lithium fluoride (LiF) anodes have larger transverse beam temperatures than laser irradiated active sources. Calculations of source divergence expected from the roughness of LiF surfaces and the possible removal of this layer is presented

  9. Ecological divergence and conservatism: spatiotemporal patterns of niche evolution in a genus of livebearing fishes (Poeciliidae: Xiphophorus).

    Science.gov (United States)

    Culumber, Zachary W; Tobler, Michael

    2016-02-19

    Ecological factors often have a strong impact on spatiotemporal patterns of biodiversity. The integration of spatial ecology and phylogenetics allows for rigorous tests of whether speciation is associated with niche conservatism (constraints on ecological divergence) or niche divergence. We address this question in a genus of livebearing fishes for which the role of sexual selection in speciation has long been studied, but in which the potential role of ecological divergence during speciation has not been tested. By combining reconstruction of ancestral climate tolerances and disparity indices, we show that the earliest evolutionary split in Xiphophorus was associated with significant divergence for temperature variables. Niche evolution and present day niches were most closely associated with each species' geographic distribution relative to a biogeographic barrier, the Trans-Mexican Volcanic Belt. Tests for similarity of the environmental backgrounds of closely related species suggested that the relative importance of niche conservatism and divergence during speciation varied among the primary clades of Xiphophorus. Closely related species in the two swordtail clades exhibited higher levels of niche overlap than expected given environmental background similarity indicative of niche conservatism. In contrast, almost all species of platyfish had significantly divergent niches compared to environmental backgrounds, which is indicative of niche divergence. The results suggest that the relative importance of niche conservatism and divergence differed among the clades of Xiphophorus and that traits associated with niche evolution may be more evolutionarily labile in the platyfishes. Our results ultimately suggest that the taxonomic scale of tests for conservatism and divergence could greatly influence inferences of their relative importance in the speciation process.

  10. The divergence theorem for divergence measure vectorfields on sets with fractal boundaries

    Czech Academy of Sciences Publication Activity Database

    Šilhavý, Miroslav

    2009-01-01

    Roč. 14, č. 5 (2009), s. 445-455 ISSN 1081-2865 Institutional research plan: CEZ:AV0Z10190503 Keywords : divergence measure vectorfields * fractal s * divergence theorem Subject RIV: BA - General Mathematics Impact factor: 1.065, year: 2009

  11. Vibhakti Divergence between Sanskrit and Hindi

    Science.gov (United States)

    Shukla, Preeti; Shukl, Devanand; Kulkarni, Amba

    Translation divergence at various levels between languages arises due to the different conventions followed by different languages for coding the information of grammatical relations. Though Sanskrit and Hindi belong to the same Indo-Aryan family and structurally as well as lexically Hindi inherits a lot from Sanskrit, yet divergences are observed at the level of function words such as vibhaktis. Pāṇini in his Aṣṭādhyāyī has assigned a default vibhakti to kārakas alongwith many scopes for exceptions. He handles these exceptions either by imposing a new kāraka role or by assigning a special vibhakti. However, these methods are not acceptable in Hindi in toto. Based on the nature of deviation, we propose seven cases of divergences in this paper.

  12. Demography and genome divergence of lake and stream populations of an East African cichlid fish.

    Science.gov (United States)

    Egger, Bernd; Roesti, Marius; Böhne, Astrid; Roth, Olivia; Salzburger, Walter

    2017-10-01

    Disentangling the processes and mechanisms underlying adaptive diversification is facilitated by the comparative study of replicate population pairs that have diverged along a similar environmental gradient. Such a setting is realized in a cichlid fish from southern Lake Tanganyika, Astatotilapia burtoni, which occurs within the lake proper as well as in various affluent rivers. Previously, we demonstrated that independent lake and stream populations show similar adaptations to the two habitat regimes. However, little is known about the evolutionary and demographic history of the A. burtoni populations in question and the patterns of genome divergence among them. Here, we apply restriction site-associated DNA sequencing (RADseq) to examine the evolutionary history, the population structure and genomic differentiation of lake and stream populations in A. burtoni. A phylogenetic reconstruction based on genome-wide molecular data largely resolved the evolutionary relationships among populations, allowing us to re-evaluate the independence of replicate lake-stream population clusters. Further, we detected a strong pattern of isolation by distance, with baseline genomic divergence increasing with geographic distance and decreasing with the level of gene flow between lake and stream populations. Genome divergence patterns were heterogeneous and inconsistent among lake-stream population clusters, which is explained by differences in divergence times, levels of gene flow and local selection regimes. In line with the latter, we only detected consistent outlier loci when the most divergent lake-stream population pair was excluded. Several of the thus identified candidate genes have inferred functions in immune and neuronal systems and show differences in gene expression between lake and stream populations. © 2017 John Wiley & Sons Ltd.

  13. Diverging expectations in buyer-seller relationships

    DEFF Research Database (Denmark)

    Andersen, Poul Houman; Christensen, Poul Rind; Damgaard, Torben

    2009-01-01

    Many firms assume that outsourcing partnerships may allow them to strengthen their overall competitiveness. Lured by its intuitive appeal, several enter into such partnerships, only to realize that they represent a marginal rather than a magical solution to their quest for increasing market...... performance. We explore the proposed impact of diverging relationship norms on relationship expectations using data from an ongoing field study of Danish buyers and Chinese suppliers. We link these diverging expectations to the business practices of Danish buyers and Chinese and their institutional contexts...

  14. Universal portfolios generated by the Bregman divergence

    Science.gov (United States)

    Tan, Choon Peng; Kuang, Kee Seng

    2017-04-01

    The Bregman divergence of two probability vectors is a stronger form of the f-divergence introduced by Csiszar. Two versions of the Bregman universal portfolio are presented by exploiting the mean-value theorem. The explicit form of the Bregman universal portfolio generated by a function of a convex polynomial is derived and studied empirically. This portfolio can be regarded as another generalized of the well-known Helmbold portfolio. By running the portfolios on selected stock-price data sets from the local stock exchange, it is shown that it is possible to increase the wealth of the investor by using the portfolios in investment.

  15. Worldwide Patterns of Ancestry, Divergence, and Admixture in Domesticated Cattle

    Science.gov (United States)

    Decker, Jared E.; McKay, Stephanie D.; Rolf, Megan M.; Kim, JaeWoo; Molina Alcalá, Antonio; Sonstegard, Tad S.; Hanotte, Olivier; Götherström, Anders; Seabury, Christopher M.; Praharani, Lisa; Babar, Masroor Ellahi; Correia de Almeida Regitano, Luciana; Yildiz, Mehmet Ali; Heaton, Michael P.; Liu, Wan-Sheng; Lei, Chu-Zhao; Reecy, James M.; Saif-Ur-Rehman, Muhammad; Schnabel, Robert D.; Taylor, Jeremy F.

    2014-01-01

    The domestication and development of cattle has considerably impacted human societies, but the histories of cattle breeds and populations have been poorly understood especially for African, Asian, and American breeds. Using genotypes from 43,043 autosomal single nucleotide polymorphism markers scored in 1,543 animals, we evaluate the population structure of 134 domesticated bovid breeds. Regardless of the analytical method or sample subset, the three major groups of Asian indicine, Eurasian taurine, and African taurine were consistently observed. Patterns of geographic dispersal resulting from co-migration with humans and exportation are recognizable in phylogenetic networks. All analytical methods reveal patterns of hybridization which occurred after divergence. Using 19 breeds, we map the cline of indicine introgression into Africa. We infer that African taurine possess a large portion of wild African auroch ancestry, causing their divergence from Eurasian taurine. We detect exportation patterns in Asia and identify a cline of Eurasian taurine/indicine hybridization in Asia. We also identify the influence of species other than Bos taurus taurus and B. t. indicus in the formation of Asian breeds. We detect the pronounced influence of Shorthorn cattle in the formation of European breeds. Iberian and Italian cattle possess introgression from African taurine. American Criollo cattle originate from Iberia, and not directly from Africa with African ancestry inherited via Iberian ancestors. Indicine introgression into American cattle occurred in the Americas, and not Europe. We argue that cattle migration, movement and trading followed by admixture have been important forces in shaping modern bovine genomic variation. PMID:24675901

  16. Codiversification of gastrointestinal microbiota and phylogeny in passerines is not explained by ecological divergence.

    Science.gov (United States)

    Kropáčková, Lucie; Těšický, Martin; Albrecht, Tomáš; Kubovčiak, Jan; Čížková, Dagmar; Tomášek, Oldřich; Martin, Jean-François; Bobek, Lukáš; Králová, Tereza; Procházka, Petr; Kreisinger, Jakub

    2017-10-01

    Vertebrate gut microbiota (GM) is comprised of a taxonomically diverse consortium of symbiotic and commensal microorganisms that have a pronounced effect on host physiology, immune system function and health status. Despite much research on interactions between hosts and their GM, the factors affecting inter- and intraspecific GM variation in wild populations are still poorly known. We analysed data on faecal microbiota composition in 51 passerine species (319 individuals) using Illumina MiSeq sequencing of bacterial 16S rRNA (V3-V4 variable region). Despite pronounced interindividual variation, GM composition exhibited significant differences at the interspecific level, accounting for approximately 20%-30% of total GM variation. We also observed a significant correlation between GM composition divergence and host's phylogenetic divergence, with strength of correlation higher than that of GM vs. ecological or life history traits and geographic variation. The effect of host's phylogeny on GM composition was significant, even after statistical control for these confounding factors. Hence, our data do not support codiversification of GM and passerine phylogeny solely as a by-product of their ecological divergence. Furthermore, our findings do not support that GM vs. host's phylogeny codiversification is driven primarily through trans-generational GM transfer as the GM vs. phylogeny correlation does not increase with higher sequence similarity used when delimiting operational taxonomic units. Instead, we hypothesize that the GM vs. phylogeny correlation may arise as a consequence of interspecific divergence of genes that directly or indirectly modulate composition of GM. © 2017 John Wiley & Sons Ltd.

  17. Stora's fine notion of divergent amplitudes

    Directory of Open Access Journals (Sweden)

    Joseph C. Várilly

    2016-11-01

    Full Text Available Stora and coworkers refined the notion of divergent quantum amplitude, somewhat upsetting the standard power-counting recipe. This unexpectedly clears the way to new prototypes for free and interacting field theories of bosons of any mass and spin.

  18. Taming infrared divergences in the effective potential

    Energy Technology Data Exchange (ETDEWEB)

    Elias-Miro, J. [IFAE, Univ. Autonoma de Barcelona (Spain); Universitat Autonoma de Barcelona (Spain). Dept. de Fisica; Espinosa, J.R. [IFAE, Univ. Autonoma de Barcelona (Spain); ICREA, Institucio Catalana de Recerca i Estudis Avancats, Barcelona (Spain); Konstandin, T. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2014-06-15

    The Higgs effective potential in the Standard Model (SM), calculated perturbatively, generically suffers from infrared (IR) divergences when the (field-dependent) tree-level mass of the Goldstone bosons goes to zero. Such divergences can affect both the potential and its first derivative and become worse with increasing loop order. In this paper we show that these IR divergences are spurious, we perform a simple resummation of all IR-problematic terms known (up to three loops) and explain how to extend the resummation to cure all such divergences to any order. The method is of general applicability and would work in scenarios other than the SM. Our discussion has some bearing on a scenario recently proposed as a mechanism for gauge mediation of scale breaking in the ultraviolet, in which it is claimed that the low-energy Higgs potential is non-standard. We argue that all non-decoupling effects from the heavy sector can be absorbed in the renormalization of low-energy parameters leading to a SM-like effective theory.

  19. Bounding the bias of contrastive divergence learning

    DEFF Research Database (Denmark)

    Fischer, Anja; Igel, Christian

    2011-01-01

    Optimization based on k-step contrastive divergence (CD) has become a common way to train restricted Boltzmann machines (RBMs). The k-step CD is a biased estimator of the log-likelihood gradient relying on Gibbs sampling. We derive a new upper bound for this bias. Its magnitude depends on k...

  20. Behavioural divergence, interfertility and speciation: a review.

    Science.gov (United States)

    Pillay, Neville; Rymer, Tasmin L

    2012-11-01

    Behavioural compatibility between mates is fundamental for maintaining species boundaries and is achieved through appropriate communication between males and females. A breakdown in communication will lead to behavioural divergence and reduced interfertility. In this review, we summarise the current knowledge on male signals and female perception of these signals, integrating the literature from several taxa. We advocate that signaller-perceiver coevolution, which is usually under strong stabilising selection to enable mating, forms the basis of species-specific mate recognition systems. The mechanisms (phylogeny, geography, ecology, biology) shaping signaller-perceiver systems are briefly discussed to demonstrate the factors underpinning the evolution of signaller-perceiver couplings. Since divergence and diversification of communication systems is driven by changes in the mechanical properties of sensory pathways and morphology of sensory organs, we highlight signal modalities (auditory, olfactory, visual, tactile) and their importance in communication, particularly in mate selection. Next, using available examples and generating a stylised model, we suggest how disruption (biological, ecological, stochastic) of signaller-perceiver systems drives behavioural divergence and consequently results in reduced interfertility and speciation. Future studies should adopt an integrative approach, combining multiple parameters (phylogeny, adaptive utility of communication systems, genetics and biomechanical/biochemical properties of signals and perception) to explore how disruption of signaller-perceiver systems results in behavioural divergence and reduced interfertility. Finally, we question the impact that rapid environmental change will have on disruption of communication systems, potentially interfering with signaller-perceiver couplings. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Hamiltonian representation of divergence-free fields

    International Nuclear Information System (INIS)

    Boozer, A.H.

    1984-11-01

    Globally divergence-free fields, such as the magnetic field and the vorticity, can be described by a two degree of freedom Hamiltonian. The Hamiltonian function provides a complete topological description of the field lines. The formulation also separates the dissipative and inertial time scale evolution of the magnetic and the vorticity fields

  2. Viewpoint Environmental Slogans: Memes with Diverging ...

    African Journals Online (AJOL)

    Environmental slogans can be seen as memes, i.e. cultural constructs that, not unlike genes, replicate themselves from one generation to the next. Memes may, however, be divergently interpreted and some memes can even have unwanted side-effects. We wanted to find out how supporters of an environmental ...

  3. The divergence theorem for unbounded vector fields

    OpenAIRE

    De Pauw, Thierry; Pfeffer, Washek F.

    2007-01-01

    In the context of Lebesgue integration, we derive the divergence theorem for unbounded vector. elds that can have singularities at every point of a compact set whose Minkowski content of codimension greater than two is. nite. The resulting integration by parts theorem is applied to removable sets of holomorphic and harmonic functions.

  4. Divergent Priors and well Behaved Bayes Factors

    NARCIS (Netherlands)

    R.W. Strachan (Rodney); H.K. van Dijk (Herman)

    2011-01-01

    textabstractDivergent priors are improper when defined on unbounded supports. Bartlett's paradox has been taken to imply that using improper priors results in ill-defined Bayes factors, preventing model comparison by posterior probabilities. However many improper priors have attractive properties

  5. The Harmonic Series Diverges Again and Again

    Science.gov (United States)

    Kifowit, Steven J.; Stamps, Terra A.

    2006-01-01

    The harmonic series is one of the most celebrated infinite series of mathematics. A quick glance at a variety of modern calculus textbooks reveals that there are two very popular proofs of the divergence of the harmonic series. In this article, the authors survey these popular proofs along with many other proofs that are equally simple and…

  6. Design of a divergence and alignment indicator

    International Nuclear Information System (INIS)

    Brenizer, J.S. Jr.; Raine, D.A.; Gao, J.; Chen, J.

    1996-01-01

    The divergence and alignment indicator (DAI) is an extension of the ASTM E803 L/D thermal neutron radiography L/D device that allows the user to determine both the beam centerline and the beam divergence. The DAI was made using aluminium plate and rods, and incorporated cadmium wire for contrast. Circular symmetry was utilized to simplify manufacture. The DAI was placed with the five posts against the film cassette or radioscopic imaging device in the physical center of the beam. The DAI was perpendicular to the selected beam radius when the front and back center Cd wire images overlap. The degree of misalignment was indicated by their image positions. After the DAI was aligned, analysis of the cadmium wire ''+'' image spacing yielded the beam divergence. The DAI was tested in a neutron beam which has an L/D of 30 but a small degree of divergence. The DAI was also imaged using an X-ray source. The point source predictions of Cd wire image locations showed good agreement with those measured from the X-ray radiograph. The neutron radiographic locations could be predicted using the point source equations, even though the neutron beam was a complex distributed source. (orig.)

  7. Enhancing Divergent Search through Extinction Events

    DEFF Research Database (Denmark)

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    for the capacity to evolve. This hypothesis is tested through experiments in two evolutionary robotics domains. The results show that combining extinction events with divergent search increases evolvability, while combining them with convergent search offers no similar benefit. The conclusion is that extinction...

  8. Taming infrared divergences in the effective potential

    International Nuclear Information System (INIS)

    Elias-Miro, J.; Konstandin, T.

    2014-06-01

    The Higgs effective potential in the Standard Model (SM), calculated perturbatively, generically suffers from infrared (IR) divergences when the (field-dependent) tree-level mass of the Goldstone bosons goes to zero. Such divergences can affect both the potential and its first derivative and become worse with increasing loop order. In this paper we show that these IR divergences are spurious, we perform a simple resummation of all IR-problematic terms known (up to three loops) and explain how to extend the resummation to cure all such divergences to any order. The method is of general applicability and would work in scenarios other than the SM. Our discussion has some bearing on a scenario recently proposed as a mechanism for gauge mediation of scale breaking in the ultraviolet, in which it is claimed that the low-energy Higgs potential is non-standard. We argue that all non-decoupling effects from the heavy sector can be absorbed in the renormalization of low-energy parameters leading to a SM-like effective theory.

  9. Solarização do solo para o controle de Pythium e plantas daninhas em cultura de crisântemo Soil solarization for Pithium and weed control in chrysanthemum crop

    Directory of Open Access Journals (Sweden)

    W. Bettiol

    1994-12-01

    Full Text Available A solarização, durante dois meses, de um solo naturalmente infestado com Pythium, promoveu o controle do patógeno, de modo semelhante à aplicação de metalaxyl + mancozeb, na cultura de crisântemo. A incidência média de plantas mortas foi de 2,3% nas parcelas solarizadas; 1,0% no solo solarizado que recebeu metade da dose dos fungicidas; 9,0% com a aplicação da dose completa dos fungicidas (1 g de metalaxyl + 4,8 g de mancozeb/m² e 38,9%, na testemunha não tratada. A solarização também promoveu o controle de plantas daninhas, avaliado através do peso da matéria seca das plantas emergentes aos 21 dias após o transplante das mudas, semelhantemente ao herbicida oxidiazon.Two months solarization of a soil naturally infested with Pythium sp. promoted a level of control similar to what was obtained with the application of methalaxyl + mancozeb for the chrysanthemum crop. The average rate of dead plants was 9.0% with the application of fungicides (1 g of methalaxyl + 4.8 g of mancozeb/ m²; 2.3% in solarized plots; 1.0% in solarized plots which received half the dosages of the fungicides and 38.9% in control plots. Similar control of weeds was obtained in solarized plots and plots treated with the herbicide oxidiazon.

  10. Multiple sclerosis: a geographical hypothesis.

    Science.gov (United States)

    Carlyle, I P

    1997-12-01

    Multiple sclerosis remains a rare neurological disease of unknown aetiology, with a unique distribution, both geographically and historically. Rare in equatorial regions, it becomes increasingly common in higher latitudes; historically, it was first clinically recognized in the early nineteenth century. A hypothesis, based on geographical reasoning, is here proposed: that the disease is the result of a specific vitamin deficiency. Different individuals suffer the deficiency in separate and often unique ways. Evidence to support the hypothesis exists in cultural considerations, in the global distribution of the disease, and in its historical prevalence.

  11. Cancellation of soft and collinear divergences in noncommutative QED

    International Nuclear Information System (INIS)

    Mirza, B.; Zarei, M.

    2006-01-01

    In this paper, we investigate the behavior of noncommutative IR divergences and will also discuss their cancellation in the physical cross sections. The commutative IR (soft) divergences existing in the nonplanar diagrams will be examined in order to prove an all-order cancellation of these divergences using the Weinberg's method. In noncommutative QED, collinear divergences due to triple photon splitting vertex, were encountered, which are shown to be canceled out by the noncommutative version of KLN theorem. This guarantees that there is no mixing between the Collinear, soft divergences and noncommutative IR divergences

  12. Changes at the National Geographic Society

    Science.gov (United States)

    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…

  13. Geographical differences in food allergy.

    Science.gov (United States)

    Bartra, Joan; García-Moral, Alba; Enrique, Ernesto

    2016-06-01

    Food allergy represents a health problem worldwide and leads to life-threatening reactions and even impairs quality of life. Epidemiological data during the past decades is very heterogeneous because of the use of different diagnostic procedures, and most studies have only been performed in specific geographical areas. The aim of this article is to review the available data on the geographical distribution of food allergies at the food source and molecular level and to link food allergy patterns to the aeroallergen influence in each area. Systematic reviews, meta-analysis, studies performed within the EuroPrevall Project and EAACI position papers regarding food allergy were analysed. The prevalence of food allergy sensitization differs between geographical areas, probably as a consequence of differences among populations, their habits and the influence of the cross-reactivity of aeroallergens and other sources of allergens. Geographical differences in food allergy are clearly evident at the allergenic molecular level, which seems to be directly influenced by the aeroallergens of each region and associated with specific clinical patterns.

  14. Educational Geographers and Applied Geography.

    Science.gov (United States)

    Frazier, John W.

    1979-01-01

    Describes the development of applied geography programs and restructuring of curricula with an emphasis on new technique and methodology courses, though retaining the liberal arts role. Educational geographers can help the programs to succeed through curriculum analysis, auditing, advising students, and liaison with other geography sources. (CK)

  15. Phylogeography of the sandy beach amphipod Haustorioides japonicus along the Sea of Japan: Paleogeographical signatures of cryptic regional divergences

    Science.gov (United States)

    Takada, Yoshitake; Sakuma, Kay; Fujii, Tetsuo; Kojima, Shigeaki

    2018-01-01

    Recent findings of genetic breaks within apparently continuous marine populations challenge the traditional vicariance paradigm in population genetics. Such "invisible" boundaries are sometimes associated with potential geographic barriers that have forced divergence of an ancestral population, habitat discontinuities, biogeographic disjunctions due to environmental gradients, or a combination of these factors. To explore the factors that influence the genetic population structure of apparently continuous populations along the Sea of Japan, the sandy beach amphipod Haustorioides japonicus was examined. We sampled a total of 300 individuals of H. japonicus from the coast of Japan, and obtained partial sequences of the mitochondrial COI gene. The sequences from 19 local populations were clustered into five groups (Northwestern Pacific, Northern, Central, Southern Sea of Japan, and East China Sea) based on a spatial genetic mixture analysis and a minimum-spanning network. AMOVA and pairwise Fst tests further supported the significant divergence of the five groups. Phylogenetic analysis revealed the relationship among the haplotypes of H. japonicus and outgroups, which inferred the northward range expansion of the species. A relaxed molecular-clock Bayesian analysis inferred the early-to middle-Pleistocene divergence of the populations. Among the five clusters, the Central Sea of Japan showed the highest values for genetic diversity indices indicating the existence of a relatively stable and large population there. The hypothesis is also supported by Bayesian Skyline Plots that showed sudden population expansion for all the clusters except for Central Sea of Japan. The present study shows genetic boundaries between the Sea of Japan and the neighboring seas, probably due to geographic isolation during the Pleistocene glacial periods. We further found divergence between the populations along the apparently continuous coast of the Sea of Japan. Historical changes in the

  16. Along the speciation continuum: Quantifying intrinsic and extrinsic isolating barriers across five million years of evolutionary divergence in California jewelflowers.

    Science.gov (United States)

    Christie, Kyle; Strauss, Sharon Y

    2018-05-01

    Understanding the relative roles of intrinsic and extrinsic reproductive barriers, and their interplay within the geographic context of diverging taxa, remains an outstanding challenge in the study of speciation. We conducted a comparative analysis of reproductive isolation in California Jewelflowers (Streptanthus, s.l., Brassicaceae) by quantifying potential barriers to gene flow at multiple life history stages in 39 species pairs spanning five million years of evolutionary divergence. We quantified nine potential pre- and postzygotic barriers and explored patterns of reproductive isolation in relation to genetic distance. Intrinsic postzygotic isolation was initially weak, increased at intermediate genetic distances, and reached a threshold characterized by complete genetic incompatibility. Climatic niche differences were strong at shallow genetic distances, and species pairs with overlapping ranges showed slight but appreciable phenological isolation, highlighting the potential for ecological barriers to contribute to speciation. Geographic analyses suggest that speciation is not regionally allopatric in the California Jewelflowers, as recently diverged taxa occur in relatively close proximity and display substantial range overlap. Young pairs are characterized by incomplete intrinsic postzygotic isolation, suggesting that extrinsic barriers or fine-scale spatial segregation are more important early in the divergence process than genetic incompatibilities. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

  17. Phenotypic Divergence in the Reproductive Traits of Marbled ...

    African Journals Online (AJOL)

    Overall, the results indicated some level of phenotypic divergence of the fish ... divergence cannot be partitioned between fishing mortality, genetic .... female fish was estimated from the egg counts ..... that greatly improved the quality of the.

  18. Endemic infrared divergences in QED3 at finite temperature

    International Nuclear Information System (INIS)

    Lo, Pok Man; Swanson, Eric S.

    2011-01-01

    We demonstrate that massless QED in three dimensions contains endemic infrared divergences. It is argued that these divergences do not affect observables; furthermore, it is possible to choose a gauge that renders the theory finite.

  19. Divergent Geophysical Evolution of Vesta and Ceres

    Science.gov (United States)

    Raymond, C. A.; Ermakov, A.; Castillo, J. C.; Fu, R. R.; McSween, H. Y., Jr.; McCord, T. B.; Park, R. S.; Russell, C. T.; De Sanctis, M. C.; Jaumann, R.; Konopliv, A. S.

    2017-12-01

    The Dawn mission explored two massive protoplanets in the main asteroid belt, Vesta and Ceres, that are fossils from the earliest epoch of solar system formation. Dawn's data provide evidence that these bodies formed very early, within the first few million years after CAIs, yet they followed divergent evolutionary paths. Vesta formed globally homogeneous distribution of minerals across the surface indicates that Ceres' interior experienced pervasive alteration. Topography and morphology of the surface reveals smoother, apparently resurfaced areas, generally at lower elevation, and rougher areas with greater relief. Local morphology such as crater floor deposits, isolated mountains, and enigmatic bright areas indicate recently active processes on Ceres, likely driven by brine cryovolcanism. Causes of the divergent evolution of these bodies include their accretionary environment, timing of accretion and size. Acknowledgements: Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration.

  20. PUBLIC INTEGRITY AND THE DIVERGENCE FROM IT

    Directory of Open Access Journals (Sweden)

    Simona‐Roxana ULMAN

    2013-12-01

    Full Text Available Public Integrity is one of the public sector’s essential objectives to attain. In contradiction, as a divergence from it, corruption is one of the persistent problems of the societies over years and it affects the credibility of public institutions and its ambassadors in front of the citizens and of the other related countries. All nations complain of corruption and, as it is observed in the Corruption Perception Index 2012, no country has a maximum score which shows that a country is totally clean. In this context, the study of the most important elements of the public integrity concept, the identification of what causes the divergence from it and the solutions detection become a relevant option for economic literature. In this context, the main objective of this paper is to emphasize the public integrity concept and its main aspects and to make a comparison between countries to achieve a large perspective of the world’s public integrity juncture.

  1. Flow over convergent and divergent wall riblets

    Energy Technology Data Exchange (ETDEWEB)

    Koeltzsch, K.; Dinkelacker, A.; Grundmann, R. [Institut fuer Luft- und Raumfahrttechnik, Technische Universitaet Dresden, 36460 Merkers (Germany)

    2002-08-01

    Fast swimming sharks have small riblets on their skin, which are assumed to improve the swimming performance of the fish. Fluid dynamic experiments in water as well as in air confirm this assumption. With riblet surfaces as compared to smooth surfaces, drag reductions up to about 10% were measured. The overall riblet pattern on sharks shows parallel riblets directed from head to tail, but besides this overall pattern fast swimming sharks have also small areas with converging riblets and others with diverging riblets. In the present study the velocity field over convergent and divergent riblet patterns is investigated by hot-wire measurements in turbulent pipe flow. Significant changes in the near wall velocity field were found. (orig.)

  2. Gluon mass generation without seagull divergences

    International Nuclear Information System (INIS)

    Aguilar, Arlene C.; Papavassiliou, Joannis

    2010-01-01

    Dynamical gluon mass generation has been traditionally plagued with seagull divergences, and all regularization procedures proposed over the years yield finite but scheme-dependent gluon masses. In this work we show how such divergences can be eliminated completely by virtue of a characteristic identity, valid in dimensional regularization. The ability to trigger the aforementioned identity hinges crucially on the particular Ansatz employed for the three-gluon vertex entering into the Schwinger-Dyson equation governing the gluon propagator. The use of the appropriate three-gluon vertex brings about an additional advantage: one obtains two separate (but coupled) integral equations, one for the effective charge and one for the gluon mass. This system of integral equations has a unique solution, which unambiguously determines these two quantities. Most notably, the effective charge freezes in the infrared, and the gluon mass displays power-law running in the ultraviolet, in agreement with earlier considerations.

  3. Increasing interpersonal trust through divergent thinking

    Directory of Open Access Journals (Sweden)

    Roberta eSellaro

    2014-06-01

    Full Text Available Interpersonal trust is an essential ingredient of many social relationships but how stable is it actually, and how is it controlled? There is evidence that the degree of trust into others might be rather volatile and can be affected by manipulations like drawing attention to personal interdependence or independence. Here we investigated whether the degree of interpersonal trust can be biased by inducing either a more integrative or a more cognitive-control mode by means of a creativity task requiring divergent or convergent thinking, respectively. Participants then performed the Trust Game, which provides an index of interpersonal trust by assessing the money units one participant (the trustor transfers to another participant (the trustee. As expected, participants transferred significantly more money to the trustee after engaging in divergent thinking as compared to convergent thinking. This observation provides support for the idea that interpersonal trust is controlled by domain-general (i.e., not socially dedicated cognitive states.

  4. High temperature phase transitions without infrared divergences

    International Nuclear Information System (INIS)

    Tetradis, N.; Wetterich, C.

    1993-09-01

    The most commonly used method for the study of high temperature phase transitions is based on the perturbative evaluation of the temperature dependent effective potential. This method becomes unreliable in the case of a second order or weakly first order phase transition, due to the appearance of infrared divergences. These divergences can be controlled through the method of the effective average action which employs renormalization group ideas. We report on the study of the high temperature phase transition for the N-component φ 4 theory. A detailed quantitative picture of the second order phase transition is presented, including the critical exponents for the behaviour in the vicinity of the critical temperature. An independent check of the results is obtained in the large N limit, and contact with the perturbative approach is established through the study of the Schwinger-Dyson equations. (orig.)

  5. COMPARATIVE FINANCIAL STATEMENTS. CONVERGENCE VERSUS DIVERGENCE

    Directory of Open Access Journals (Sweden)

    Nicolae ECOBICI

    2010-09-01

    Full Text Available In this paper I compared the Romanian financial statements with the US GAAP financial statements in terms of two criteria: first the reference period and secondly the shape, structure and content of financial statements. Nowadays the two accounting systems, the French and Anglo-Saxon, tend to harmonize. I will present the convergences and the divergences between the financial statements of Romania, subject to OMFP 3055/2009, in parallel with the Anglo-Saxon accounting system.

  6. Divergent Effects of Dendritic Cells on Pancreatitis

    Science.gov (United States)

    2015-09-01

    role of dendritic cells in pancreatitis. Dendritic cells are professional antigen presenting cells which initiate innate and adaptive immune... Lymphoid -tissue-specific homing of bone- marrow-derived dendritic cells . Blood. 113:6638–6647. http://dx.doi .org/10.1182/blood-2009-02-204321 Dapito...Award Number: W81XWH-12-1-0313 TITLE: Divergent Effects of Dendritic Cells on Pancreatitis PRINCIPAL INVESTIGATOR: Dr. George Miller

  7. Initial States: IR and Collinear Divergences

    International Nuclear Information System (INIS)

    Lavelle, Martin; McMullan, David

    2007-01-01

    The standard approach to the infra-red problem is to use the Bloch-Nordsieck trick to handle soft divergences and the Lee-Nauenberg (LN) theorem for collinear singularities. We show that this is inconsistent in the presence of massless initial particles. Furthermore, we show that using the LN theorem with such initial states introduces a non-convergent infinite series of diagrams at any fixed order in perturbation theory

  8. Carnot efficiency at divergent power output

    Science.gov (United States)

    Polettini, Matteo; Esposito, Massimiliano

    2017-05-01

    The widely debated feasibility of thermodynamic machines achieving Carnot efficiency at finite power has been convincingly dismissed. Yet, the common wisdom that efficiency can only be optimal in the limit of infinitely slow processes overlooks the dual scenario of infinitely fast processes. We corroborate that efficient engines at divergent power output are not theoretically impossible, framing our claims within the theory of Stochastic Thermodynamics. We inspect the case of an electronic quantum dot coupled to three particle reservoirs to illustrate the physical rationale.

  9. Fast algorithms for computing phylogenetic divergence time.

    Science.gov (United States)

    Crosby, Ralph W; Williams, Tiffani L

    2017-12-06

    The inference of species divergence time is a key step in most phylogenetic studies. Methods have been available for the last ten years to perform the inference, but the performance of the methods does not yet scale well to studies with hundreds of taxa and thousands of DNA base pairs. For example a study of 349 primate taxa was estimated to require over 9 months of processing time. In this work, we present a new algorithm, AncestralAge, that significantly improves the performance of the divergence time process. As part of AncestralAge, we demonstrate a new method for the computation of phylogenetic likelihood and our experiments show a 90% improvement in likelihood computation time on the aforementioned dataset of 349 primates taxa with over 60,000 DNA base pairs. Additionally, we show that our new method for the computation of the Bayesian prior on node ages reduces the running time for this computation on the 349 taxa dataset by 99%. Through the use of these new algorithms we open up the ability to perform divergence time inference on large phylogenetic studies.

  10. Two families of astrophysical diverging lens models

    Science.gov (United States)

    Er, Xinzhong; Rogers, Adam

    2018-03-01

    In the standard gravitational lensing scenario, rays from a background source are bent in the direction of a foreground lensing mass distribution. Diverging lens behaviour produces deflections in the opposite sense to gravitational lensing, and is also of astrophysical interest. In fact, diverging lensing due to compact distributions of plasma has been proposed as an explanation for the extreme scattering events that produce frequency-dependent dimming of extragalactic radio sources, and may also be related to the refractive radio wave phenomena observed to affect the flux density of pulsars. In this work we study the behaviour of two families of astrophysical diverging lenses in the geometric optics limit, the power law, and the exponential plasma lenses. Generally, the members of these model families show distinct behaviour in terms of image formation and magnification, however the inclusion of a finite core for certain power-law lenses can produce a caustic and critical curve morphology that is similar to the well-studied Gaussian plasma lens. Both model families can produce dual radial critical curves, a novel distinction from the tangential distortion usually produced by gravitational (converging) lenses. The deflection angle and magnification of a plasma lens vary with the observational frequency, producing wavelength-dependent magnifications that alter the amplitudes and the shape of the light curves. Thus, multiwavelength observations can be used to physically constrain the distribution of the electron density in such lenses.

  11. An Exponential Regulator for Rapidity Divergences

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ye [Fermilab; Neill, Duff [MIT, Cambridge, CTP; Zhu, Hua Xing [MIT, Cambridge, CTP

    2016-04-01

    Finding an efficient and compelling regularization of soft and collinear degrees of freedom at the same invariant mass scale, but separated in rapidity is a persistent problem in high-energy factorization. In the course of a calculation, one encounters divergences unregulated by dimensional regularization, often called rapidity divergences. Once regulated, a general framework exists for their renormalization, the rapidity renormalization group (RRG), leading to fully resummed calculations of transverse momentum (to the jet axis) sensitive quantities. We examine how this regularization can be implemented via a multi-differential factorization of the soft-collinear phase-space, leading to an (in principle) alternative non-perturbative regularization of rapidity divergences. As an example, we examine the fully-differential factorization of a color singlet's momentum spectrum in a hadron-hadron collision at threshold. We show how this factorization acts as a mother theory to both traditional threshold and transverse momentum resummation, recovering the classical results for both resummations. Examining the refactorization of the transverse momentum beam functions in the threshold region, we show that one can directly calculate the rapidity renormalized function, while shedding light on the structure of joint resummation. Finally, we show how using modern bootstrap techniques, the transverse momentum spectrum is determined by an expansion about the threshold factorization, leading to a viable higher loop scheme for calculating the relevant anomalous dimensions for the transverse momentum spectrum.

  12. The direct Flow parametric Proof of Gauss' Divergence Theorem revisited

    DEFF Research Database (Denmark)

    Markvorsen, Steen

    The standard proof of the divergence theorem in undergraduate calculus courses covers the theorem for static domains between two graph surfaces. We show that within first year undergraduate curriculum, the flow proof of the dynamic version of the divergence theorem - which is usually considered...... we apply the key instrumental concepts and verify the various steps towards this alternative proof of the divergence theorem....

  13. IL FENOMENO VOLUNTEERED GEOGRAPHIC INFORMATION

    Directory of Open Access Journals (Sweden)

    Flavio Lupia

    2014-12-01

    Full Text Available The contribution addresses the phenomenon of Voluntereed Geographic Informationexplaining these new and burgeoning sources of information offers multidisciplinary scientists an unprecedented opportunity to conduct research on a variety of topics at multiple spatial and temporal scales. In particular the contribution refers to two COST Actions which have been recently activated on the subject which areparticularly relevant for the growing of the European scientific community.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Ruth E. Rodríguez-Tejeda

    2014-06-01

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

  16. Variational divergence in wave scattering theory with Kirchhoffean trial functions

    Science.gov (United States)

    Bird, J. F.

    1986-01-01

    In a recent study of variational improvement of the Kirchhoff approximation for electromagnetic scattering by rough surfaces, a key ingredient in the variational principle was found to diverge for important configurations (e.g., backscatter) if the polarization had any vertical component. The cause and a cure of this divergence are discussed here. The divergence is demonstrated to occur for arbitrary perfectly conducting scatterers and its universal characterstics are determined, by means of a general divergence criterion that is derived. A variational cure for the divergence is prescribed, and it is tested successfully on a standard scattering model.

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

    Science.gov (United States)

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

    2007-12-01

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

  18. Divergent Macroparasite Infections in Parapatric Swiss Lake-Stream Pairs of Threespine Stickleback (Gasterosteus aculeatus.

    Directory of Open Access Journals (Sweden)

    Anssi Karvonen

    Full Text Available Spatial heterogeneity in diversity and intensity of parasitism is a typical feature of most host-parasite interactions, but understanding of the evolutionary implications of such variation is limited. One possible outcome of infection heterogeneities is parasite-mediated divergent selection between host populations, ecotypes or species which may facilitate the process of ecological speciation. However, very few studies have described infections in population-pairs along the speciation continuum from low to moderate or high degree of genetic differentiation that would address the possibility of parasite-mediated divergent selection in the early stages of the speciation process. Here we provide an example of divergent parasitism in freshwater fish ecotypes by examining macroparasite infections in threespine stickleback (Gasterosteus aculeatus of four Swiss lake systems each harbouring parapatric lake-stream ecotype pairs. We demonstrate significant differences in infections within and between the pairs that are driven particularly by the parasite taxa transmitted to fish from benthic invertebrates. The magnitude of the differences tended to correlate positively with the extent of neutral genetic differentiation between the parapatric lake and stream populations of stickleback, whereas no such correlation was found among allopatric populations from similar or contrasting habitats. This suggests that genetic differentiation is unrelated to the magnitude of parasite infection contrasts when gene flow is constrained by geographical barriers while in the absence of physical barriers, genetic differentiation and the magnitude of differences in infections tend to be positively correlated.

  19. Divergent Macroparasite Infections in Parapatric Swiss Lake-Stream Pairs of Threespine Stickleback (Gasterosteus aculeatus).

    Science.gov (United States)

    Karvonen, Anssi; Lucek, Kay; Marques, David A; Seehausen, Ole

    2015-01-01

    Spatial heterogeneity in diversity and intensity of parasitism is a typical feature of most host-parasite interactions, but understanding of the evolutionary implications of such variation is limited. One possible outcome of infection heterogeneities is parasite-mediated divergent selection between host populations, ecotypes or species which may facilitate the process of ecological speciation. However, very few studies have described infections in population-pairs along the speciation continuum from low to moderate or high degree of genetic differentiation that would address the possibility of parasite-mediated divergent selection in the early stages of the speciation process. Here we provide an example of divergent parasitism in freshwater fish ecotypes by examining macroparasite infections in threespine stickleback (Gasterosteus aculeatus) of four Swiss lake systems each harbouring parapatric lake-stream ecotype pairs. We demonstrate significant differences in infections within and between the pairs that are driven particularly by the parasite taxa transmitted to fish from benthic invertebrates. The magnitude of the differences tended to correlate positively with the extent of neutral genetic differentiation between the parapatric lake and stream populations of stickleback, whereas no such correlation was found among allopatric populations from similar or contrasting habitats. This suggests that genetic differentiation is unrelated to the magnitude of parasite infection contrasts when gene flow is constrained by geographical barriers while in the absence of physical barriers, genetic differentiation and the magnitude of differences in infections tend to be positively correlated.

  20. Adaptive divergence in the monkey flower Mimulus guttatus is maintained by a chromosomal inversion.

    Science.gov (United States)

    Twyford, Alex D; Friedman, Jannice

    2015-06-01

    Organisms exhibit an incredible diversity of life history strategies as adaptive responses to environmental variation. The establishment of novel life history strategies involves multilocus polymorphisms, which will be challenging to establish in the face of gene flow and recombination. Theory predicts that adaptive allelic combinations may be maintained and spread if they occur in genomic regions of reduced recombination, such as chromosomal inversion polymorphisms, yet empirical support for this prediction is lacking. Here, we use genomic data to investigate the evolution of divergent adaptive ecotypes of the yellow monkey flower Mimulus guttatus. We show that a large chromosomal inversion polymorphism is the major region of divergence between geographically widespread annual and perennial ecotypes. In contrast, ∼40,000 single nucleotide polymorphisms in collinear regions of the genome show no signal of life history, revealing genomic patterns of diversity have been shaped by localized homogenizing gene flow and large-scale Pleistocene range expansion. Our results provide evidence for an inversion capturing and protecting loci involved in local adaptation, while also explaining how adaptive divergence can occur with gene flow. © 2015 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

  1. Cryptic lineage diversity, body size divergence, and sympatry in a species complex of Australian lizards (Gehyra).

    Science.gov (United States)

    Moritz, Craig C; Pratt, Renae C; Bank, Sarah; Bourke, Gayleen; Bragg, Jason G; Doughty, Paul; Keogh, J Scott; Laver, Rebecca J; Potter, Sally; Teasdale, Luisa C; Tedeschi, Leonardo G; Oliver, Paul M

    2018-01-01

    Understanding the joint evolutionary and ecological underpinnings of sympatry among close relatives remains a key challenge in biology. This problem can be addressed through joint phylogenomic and phenotypic analysis of complexes of closely related lineages within, and across, species and hence representing the speciation continuum. For a complex of tropical geckos from northern Australia-Gehyra nana and close relatives-we combine mtDNA phylogeography, exon-capture sequencing, and morphological data to resolve independently evolving lineages and infer their divergence history and patterns of morphological evolution. Gehyra nana is found to include nine divergent lineages and is paraphyletic with four other species from the Kimberley region of north-west Australia. Across these 13 taxa, 12 of which are restricted to rocky habitats, several lineages overlap geographically, including on the diverse Kimberley islands. Morphological evolution is dominated by body size shifts, and both body size and shape have evolved gradually across the group. However, larger body size shifts are observed among overlapping taxa than among closely related parapatric lineages of G. nana, and sympatric lineages are more divergent than expected at random. Whether elevated body size differences among sympatric lineages are due to ecological sorting or character displacement remains to be determined. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  2. Mechanisms by Which Phenotypic Plasticity Affects Adaptive Divergence and Ecological Speciation.

    Science.gov (United States)

    Nonaka, Etsuko; Svanbäck, Richard; Thibert-Plante, Xavier; Englund, Göran; Brännström, Åke

    2015-11-01

    Phenotypic plasticity is the ability of one genotype to produce different phenotypes depending on environmental conditions. Several conceptual models emphasize the role of plasticity in promoting reproductive isolation and, ultimately, speciation in populations that forage on two or more resources. These models predict that plasticity plays a critical role in the early stages of speciation, prior to genetic divergence, by facilitating fast phenotypic divergence. The ability to plastically express alternative phenotypes may, however, interfere with the early phase of the formation of reproductive barriers, especially in the absence of geographic barriers. Here, we quantitatively investigate mechanisms under which plasticity can influence progress toward adaptive genetic diversification and ecological speciation. We use a stochastic, individual-based model of a predator-prey system incorporating sexual reproduction and mate choice in the predator. Our results show that evolving plasticity promotes the evolution of reproductive isolation under diversifying environments when individuals are able to correctly select a more profitable habitat with respect to their phenotypes (i.e., adaptive habitat choice) and to assortatively mate with relatively similar phenotypes. On the other hand, plasticity facilitates the evolution of plastic generalists when individuals have a limited capacity for adaptive habitat choice. We conclude that plasticity can accelerate the evolution of a reproductive barrier toward adaptive diversification and ecological speciation through enhanced phenotypic differentiation between diverging phenotypes.

  3. Geographic Names Information System (GNIS) Structures

    Data.gov (United States)

    Department of Homeland Security — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  4. Geographic Names Information System (GNIS) Historical Features

    Data.gov (United States)

    Department of Homeland Security — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  5. Geographic Names Information System (GNIS) Admin Features

    Data.gov (United States)

    Department of Homeland Security — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  6. Geographic Names Information System (GNIS) Hydrography Lines

    Data.gov (United States)

    Department of Homeland Security — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  7. Geographic Names Information System (GNIS) Cultural Features

    Data.gov (United States)

    Department of Homeland Security — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  8. Geographic Names Information System (GNIS) Landform Features

    Data.gov (United States)

    Department of Homeland Security — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  9. Geographic Names Information System (GNIS) Hydrography Points

    Data.gov (United States)

    Department of Homeland Security — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  10. Geographic Names Information System (GNIS) Community Features

    Data.gov (United States)

    Department of Homeland Security — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  11. Geographic Names Information System (GNIS) Transportation Features

    Data.gov (United States)

    Department of Homeland Security — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  12. Geographic Names Information System (GNIS) Antarctica Features

    Data.gov (United States)

    Department of Homeland Security — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  13. Cryptic diversity and deep divergence in an upper Amazonian leaflitter frog, Eleutherodactylus ockendeni

    Directory of Open Access Journals (Sweden)

    Dávila José A

    2007-12-01

    Full Text Available Abstract Background The forests of the upper Amazon basin harbour some of the world's highest anuran species richness, but to date we have only the sparsest understanding of the distribution of genetic diversity within and among species in this region. To quantify region-wide genealogical patterns and to test for the presence of deep intraspecific divergences that have been documented in some other neotropical anurans, we developed a molecular phylogeny of the wide-spread terrestrial leaflitter frog Eleutherodactylus ockendeni (Leptodactylidae from 13 localities throughout its range in Ecuador using data from two mitochondrial genes (16S and cyt b; 1246 base pairs. We examined the relation between divergence of mtDNA and the nuclear genome, as sampled by five species-specific microsatellite loci, to evaluate indirectly whether lineages are reproductively isolated where they co-occur. Our extensive phylogeographic survey thus assesses the spatial distribution of E. ockendeni genetic diversity across eastern Ecuador. Results We identified three distinct and well-supported clades within the Ecuadorean range of E. ockendeni: an uplands clade spanning north to south, a northeastern and central lowlands clade, and a central and southeastern clade, which is basal. Clades are separated by 12% to 15% net corrected p-distance for cytochrome b, with comparatively low sequence divergence within clades. Clades marginally overlap in some geographic areas (e.g., Napo River basin but are reproductively isolated, evidenced by diagnostic differences in microsatellite PCR amplification profiles or DNA repeat number and coalescent analyses (in MDIV best modelled without migration. Using Bayesian (BEAST and net phylogenetic estimates, the Southeastern Clade diverged from the Upland/Lowland clades in the mid-Miocene or late Oligocene. Lowland and Upland clades speciated more recently, in the early or late Miocene. Conclusion Our findings uncover previously

  14. The Eurozone Dynamic Cohesion: Convergence or Divergence

    Directory of Open Access Journals (Sweden)

    Antonin Rusek

    2013-08-01

    Full Text Available The long term economic dynamics of the Eurozone’s original 12 countries (Greece, Italy, Spain, Portugal, Ireland, Germany, Netherlands, Luxembourg, Belgium, Austria, Finland, France is analyzed and compared. It is today increasingly recognized that the diverging competitiveness between the Eurozone members is at the root of the current crisis. But the competitiveness dynamics and its impact on the crucial fiscal and financial variables during the common currency existence is seldom analyzed and compared, especially as far as the different groups of countries (and/or different areas within the Eurozone are concerned.

  15. Diverging patterns with endogenous labor migration.

    Science.gov (United States)

    Reichlin, P; Rustichini, A

    1998-05-05

    "The standard neoclassical model cannot explain persistent migration flows and lack of cross-country convergence when capital and labor are mobile. Here we present a model where both phenomena may take place.... Our model is based on the Arrow-Romer approach to endogenous growth theory. We single out the importance of a (however weak) scale effect from the size of the workforce.... The main conclusion of this simple model is that lack of convergence, or even divergence, among countries is possible, even with perfect capital mobility and labor mobility." excerpt

  16. Projection Pursuit Through ϕ-Divergence Minimisation

    Directory of Open Access Journals (Sweden)

    Jacques Touboul

    2010-06-01

    Full Text Available In his 1985 article (“Projection pursuit”, Huber demonstrates the interest of his method to estimate a density from a data set in a simple given case. He considers the factorization of density through a Gaussian component and some residual density. Huber’s work is based on maximizing Kullback–Leibler divergence. Our proposal leads to a new algorithm. Furthermore, we will also consider the case when the density to be factorized is estimated from an i.i.d. sample. We will then propose a test for the factorization of the estimated density. Applications include a new test of fit pertaining to the elliptical copulas.

  17. Divergence-based tests for model diagnostic

    Czech Academy of Sciences Publication Activity Database

    Hobza, Tomáš; Esteban, M. D.; Morales, D.; Marhuenda, Y.

    2008-01-01

    Roč. 78, č. 13 (2008), s. 1702-1710 ISSN 0167-7152 R&D Projects: GA MŠk 1M0572 Grant - others:Instituto Nacional de Estadistica (ES) MTM2006-05693 Institutional research plan: CEZ:AV0Z10750506 Keywords : goodness of fit * devergence statistics * GLM * model checking * bootstrap Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.445, year: 2008 http://library.utia.cas.cz/separaty/2008/SI/hobza-divergence-based%20tests%20for%20model%20diagnostic.pdf

  18. Diverging expectations in buyer-seller relationships

    DEFF Research Database (Denmark)

    Andersen, Poul Houman; Christensen, Poul Rind; Damgaard, Torben

    2009-01-01

    Many firms assume that outsourcing partnerships may allow them to strengthen their overall competitiveness. Lured by its intuitive appeal, several enter into such partnerships, only to realize that they represent a marginal rather than a magical solution to their quest for increasing market...... SMEs. We discuss four relational expectations derived from the B2B literature on relational norms for addressing these divergences: Quality, frequency and scope of communication, role specifications and coordination of work nature of planning horizons, and trustworthiness and link these to relationship...

  19. Combined venomics, venom gland transcriptomics, bioactivities, and antivenomics of two Bothrops jararaca populations from geographic isolated regions within the Brazilian Atlantic rainforest

    OpenAIRE

    Gonçalves Machado, Larissa; Pla, Davinia; Sanz, Libia; Jorge, Roberta Jeane B.; Leitão De Araújo, Moema; Alves, Maria Lúcia M.; Alvares, Diego Janisch; De Miranda, Joari; Nowatzki, Jenifer; de Morais Zani, Karen; Fernandes, Wilson; Tanaka Azevedo, Anita Mitico; Fernández, Julián; Zingali, Russolina B.; Gutiérrez, José María

    2016-01-01

    Bothrops jararaca is a slender and semi-arboreal medically relevant pit viper species endemic to tropical and subtropical forests in southern Brazil, Paraguay, and northern Argentina (Misiones). Within its geographic range, it is often abundant and is an important cause of snakebite. Although no subspecies are currently recognized, geographic analyses have revealed the existence of two well-supported B. jararaca clades that diverged during the Pliocene ~ 3.8 Mya and currently display a southe...

  20. 5 CFR 536.303 - Geographic conversion.

    Science.gov (United States)

    2010-01-01

    ... after geographic conversion is the employee's existing payable rate of basic pay in effect immediately before the action. (b) Geographic conversion when a retained rate employee's official worksite is changed... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Geographic conversion. 536.303 Section...

  1. World health inequality: convergence, divergence, and development.

    Science.gov (United States)

    Clark, Rob

    2011-02-01

    Recent studies characterize the last half of the twentieth century as an era of cross-national health convergence, with some attributing welfare gains in the developing world to economic growth. In this study, I examine the extent to which welfare outcomes have actually converged and the extent to which economic development is responsible for the observed trends. Drawing from estimates covering 195 nations during the 1955-2005 period, I find that life expectancy averages converged during this time, but that infant mortality rates continuously diverged. I develop a narrative that implicates economic development in these contrasting trends, suggesting that health outcomes follow a "welfare Kuznets curve." Among poor countries, economic development improves life expectancy more than it reduces infant mortality, whereas the situation is reversed among wealthier nations. In this way, development has contributed to both convergence in life expectancy and divergence in infant mortality. Drawing from 674 observations across 163 countries during the 1980-2005 period, I find that the positive effect of GDP PC on life expectancy attenuates at higher levels of development, while the negative effect of GDP PC on infant mortality grows stronger. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Natural Scales in Geographical Patterns

    Science.gov (United States)

    Menezes, Telmo; Roth, Camille

    2017-04-01

    Human mobility is known to be distributed across several orders of magnitude of physical distances, which makes it generally difficult to endogenously find or define typical and meaningful scales. Relevant analyses, from movements to geographical partitions, seem to be relative to some ad-hoc scale, or no scale at all. Relying on geotagged data collected from photo-sharing social media, we apply community detection to movement networks constrained by increasing percentiles of the distance distribution. Using a simple parameter-free discontinuity detection algorithm, we discover clear phase transitions in the community partition space. The detection of these phases constitutes the first objective method of characterising endogenous, natural scales of human movement. Our study covers nine regions, ranging from cities to countries of various sizes and a transnational area. For all regions, the number of natural scales is remarkably low (2 or 3). Further, our results hint at scale-related behaviours rather than scale-related users. The partitions of the natural scales allow us to draw discrete multi-scale geographical boundaries, potentially capable of providing key insights in fields such as epidemiology or cultural contagion where the introduction of spatial boundaries is pivotal.

  3. OUTDOOR EDUCATION AND GEOGRAPHICAL EDUCATION

    Directory of Open Access Journals (Sweden)

    ANDREA GUARAN

    2016-01-01

    Full Text Available This paper focuses on the reflection on the relationship between values and methodological principles of Outdoor Education and spatial and geographical education perspectives, especially in pre-school and primary school, which relates to the age between 3 and 10 years. Outdoor Education is an educational practice that is already rooted in the philosophical thought of the 16th and the 17th centuries, from John Locke to Jean-Jacques Rousseau, and in the pedagogical thought, in particular Friedrich Fröbel, and it has now a quite stable tradition in Northern Europe countries. In Italy, however, there are still few experiences and they usually do not have a systematic and structural modality, but rather a temporarily and experimentally outdoor organization. In the first part, this paper focuses on the reasons that justify a particular attention to educational paths that favour outdoors activities, providing also a definition of outdoor education and highlighting its values. It is also essential to understand that educational programs in open spaces, such as a forest or simply the schoolyard, surely offers the possibility to learn geographical situations. Therefore, the question that arises is how to finalize the best stimulus that the spatial location guarantees for the acquisition of knowledge, skills and abilities about space and geography.

  4. Geographic profiling and animal foraging.

    Science.gov (United States)

    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.

  5. ROMANIA: GEOGRAPHICAL AND GEOPOLITICAL POSITION

    Directory of Open Access Journals (Sweden)

    Ciprian Beniamin Benea

    2016-12-01

    Full Text Available The paper intends to bring to the reader’s attention the importance of understanding the role education plays in creating a good geopolitical position for a state which has a good geographical position, and which is well endowed in natural resources. The case of Romania is the main focus of the paper. There is presented a peculiar strange situation of a country (Romania which is very well located from geographical point of view but which is incapable to exploit its natural endowments and special location. One reason for this situation is the fact that most people living in present Romania belong to a category named in this paper ‘individuals’. Individuals are not aware of their country’s geography and history, let alone its possible future development possibilities. They do not know the role their country could play, and living in an atomized society, they choose emigration as the easiest way to escape harsh social and economic environment. Contrary to this attitude is that of a citizen, a man conscious about his country’s potential, and which is dedicated to work hardly together with his fellows in order to promote national interests in a peaceful manner. Even there was found remnants of an ancient city close to present day Romanian territory – proves of well endowed environment – moral and psychological factors have contributed after 1990 in an crucial manner to push Romania from its civilization path back to the archaic spirit, from active urban spirit to rural mentality. In such a situation it is not uncommon for a nation to lose its means for projecting power, which could promote the value and the importance of a geographical position – transportation; rural mentality has nothing to do with modern transportation as they are technical tools with geopolitical essence for controlling space. It is a well known fact that transportation and geopolitics are closely interrelated. Furthermore, social dissolution in post communist

  6. Floral and mating system divergence in secondary sympatry: testing an alternative hypothesis to reinforcement in Clarkia

    Science.gov (United States)

    Briscoe Runquist, Ryan D.; Moeller, David A.

    2014-01-01

    Background and Aims Reproductive character displacement (RCD) is often an important signature of reinforcement when partially cross-compatible taxa meet in secondary sympatry. In this study, floral evolution is examined during the Holocene range expansion of Clarkia xantiana subsp. parviflora from eastern Pleistocene refugia to a western zone of sympatry with its sister taxon, subsp. xantiana. Floral divergence between the two taxa is greater in sympatry than allopatry. The goal was to test an alternative hypothesis to reinforcement – that floral divergence of sympatric genotypes is simply a by-product of adaptation to pollination environments that differ between the allopatric and sympatric portions of the subspecies' range. Methods Floral trait data from two common garden studies were used to examine floral divergence between sympatric and allopatric regions and among phylogeographically defined lineages. In natural populations of C. x. parviflora, the magnitude of pollen limitation and reproductive assurance were quantified across its west-to-east range. Potted sympatric and allopatric genotypes were also reciprocally translocated between geographical regions to distinguish between the effects of floral phenotype versus contrasting pollinator environments on reproductive ecology. Key Results Sympatric populations are considerably smaller flowered with reduced herkogamy. Pollen limitation and the reproductive assurance value of selfing are greater in sympatric than in allopatric populations. Most significantly, reciprocal translocation experiments showed these differences in reproductive ecology cannot be attributed to contrasting pollinator environments between the sympatric and allopatric regions, but instead reflect the effects of flower size on pollinator attraction. Conclusions Floral evolution occurred during the westward range expansion of parviflora, particularly in the zone of sympatry with xantiana. No evidence was found that strongly reduced flower

  7. Isolation with asymmetric gene flow during the nonsynchronous divergence of dry forest birds.

    Science.gov (United States)

    Oswald, Jessica A; Overcast, Isaac; Mauck, William M; Andersen, Michael J; Smith, Brian Tilston

    2017-03-01

    Dry forest bird communities in South America are often fragmented by intervening mountains and rainforests, generating high local endemism. The historical assembly of dry forest communities likely results from dynamic processes linked to numerous population histories among codistributed species. Nevertheless, species may diversify in the same way through time if landscape and environmental features, or species ecologies, similarly structure populations. Here we tested whether six co-distributed taxon pairs that occur in the dry forests of the Tumbes and Marañón Valley of northwestern South America show concordant patterns and modes of diversification. We employed a genome reduction technique, double-digest restriction site-associated DNA sequencing, and obtained 4407-7186 genomewide SNPs. We estimated demographic history in each taxon pair and inferred that all pairs had the same best-fit demographic model: isolation with asymmetric gene flow from the Tumbes into the Marañón Valley, suggesting a common diversification mode. Overall, we also observed congruence in effective population size (N e ) patterns where ancestral N e were 2.9-11.0× larger than present-day Marañón Valley populations and 0.3-2.0× larger than Tumbesian populations. Present-day Marañón Valley N e was smaller than Tumbes. In contrast, we found simultaneous population isolation due to a single event to be unlikely as taxon pairs diverged over an extended period of time (0.1-2.9 Ma) with multiple nonoverlapping divergence periods. Our results show that even when populations of codistributed species asynchronously diverge, the mode of their differentiation can remain conserved over millions of years. Divergence by allopatric isolation due to barrier formation does not explain the mode of differentiation between these two bird assemblages; rather, migration of individuals occurred before and after geographic isolation. © 2017 John Wiley & Sons Ltd.

  8. Intraspecific ecological niche divergence and reproductive shifts foster cytotype displacement and provide ecological opportunity to polyploids.

    Science.gov (United States)

    Karunarathne, Piyal; Schedler, Mara; Martínez, Eric J; Honfi, Ana I; Novichkova, Anastasiia; Hojsgaard, Diego

    2018-05-11

    Niche divergence between polyploids and their lower ploidy progenitors is one of the primary mechanisms fostering polyploid establishment and adaptive divergence. However, within-species chromosomal and reproductive variability have usually been neglected in community ecology and biodiversity analyses even though they have been recognized to play a role in the adaptive diversification of lineages. We used Paspalum intermedium, a grass species with diverging genetic systems (diploidy vs. autopolyploidy, allogamy vs. autogamy and sexuality vs. apomixis), to recognize the causality of biogeographic patterns, adaptation and ecological flexibility of cytotypes. Chromosome counts and flow cytometry were used to characterize within-species genetic systems diversity. Environmental niche modelling was used to evaluate intraspecific ecological attributes associated with environmental and climatic factors and to assess correlations among ploidy, reproductive modes and ecological conditions ruling species' population dynamics, range expansion, adaptation and evolutionary history. Two dominant cytotypes non-randomly distributed along local and regional geographical scales displayed niche differentiation, a directional shift in niche optima and signs of disruptive selection on ploidy-related ecological aptitudes for the exploitation of environmental resources. Ecologically specialized allogamous sexual diploids were found in northern areas associated with higher temperature, humidity and productivity, while generalist autogamous apomictic tetraploids occurred in southern areas, occupying colder and less productive environments. Four localities with a documented shift in ploidy and four mixed populations in a zone of ecological transition revealed an uneven replacement between cytotypes. Polyploidy and contrasting reproductive traits between cytotypes have promoted shifts in niche optima, and increased ecological tolerance and niche divergence. Ecologically specialized diploids

  9. Floral and mating system divergence in secondary sympatry: testing an alternative hypothesis to reinforcement in Clarkia.

    Science.gov (United States)

    Briscoe Runquist, Ryan D; Moeller, David A

    2014-01-01

    Reproductive character displacement (RCD) is often an important signature of reinforcement when partially cross-compatible taxa meet in secondary sympatry. In this study, floral evolution is examined during the Holocene range expansion of Clarkia xantiana subsp. parviflora from eastern Pleistocene refugia to a western zone of sympatry with its sister taxon, subsp. xantiana. Floral divergence between the two taxa is greater in sympatry than allopatry. The goal was to test an alternative hypothesis to reinforcement - that floral divergence of sympatric genotypes is simply a by-product of adaptation to pollination environments that differ between the allopatric and sympatric portions of the subspecies' range. Floral trait data from two common garden studies were used to examine floral divergence between sympatric and allopatric regions and among phylogeographically defined lineages. In natural populations of C. x. parviflora, the magnitude of pollen limitation and reproductive assurance were quantified across its west-to-east range. Potted sympatric and allopatric genotypes were also reciprocally translocated between geographical regions to distinguish between the effects of floral phenotype versus contrasting pollinator environments on reproductive ecology. Sympatric populations are considerably smaller flowered with reduced herkogamy. Pollen limitation and the reproductive assurance value of selfing are greater in sympatric than in allopatric populations. Most significantly, reciprocal translocation experiments showed these differences in reproductive ecology cannot be attributed to contrasting pollinator environments between the sympatric and allopatric regions, but instead reflect the effects of flower size on pollinator attraction. Floral evolution occurred during the westward range expansion of parviflora, particularly in the zone of sympatry with xantiana. No evidence was found that strongly reduced flower size in sympatric parviflora (and RCD between

  10. Low Divergence of Clonorchis sinensis in China Based on Multilocus Analysis.

    Directory of Open Access Journals (Sweden)

    Jiufeng Sun

    Full Text Available Clonorchis sinensis, an ancient parasite that infects a number of piscivorous mammals, attracts significant public health interest due to zoonotic exposure risks in Asia. The available studies are insufficient to reflect the prevalence, geographic distribution, and intraspecific genetic diversity of C. sinensis in endemic areas. Here, a multilocus analysis based on eight genes (ITS1, act, tub, ef-1a, cox1, cox3, nad4 and nad5 [4.986 kb] was employed to explore the intra-species genetic construction of C. sinensis in China. Two hundred and fifty-six C. sinensis isolates were obtained from environmental reservoirs from 17 provinces of China. A total of 254 recognized Multilocus Types (MSTs showed high diversity among these isolates using multilocus analysis. The comparison analysis of nuclear and mitochondrial phylogeny supports separate clusters in a nuclear dendrogram. Genetic differentiation analysis of three clusters (A, B, and C showed low divergence within populations. Most isolates from clusters B and C are geographically limited to central China, while cluster A is extraordinarily genetically diverse. Further genetic analyses between different geographic distributions, water bodies and hosts support the low population divergence. The latter haplotype analyses were consistent with the phylogenetic and genetic differentiation results. A recombination network based on concatenated sequences showed a concentrated linkage recombination population in cox1, cox3, nad4 and nad5, with spatial structuring in ITS1. Coupled with the history record and archaeological evidence of C. sinensis infection in mummified desiccated feces, these data point to an ancient origin of C. sinensis in China. In conclusion, we present a likely phylogenetic structure of the C. sinensis population in mainland China, highlighting its possible tendency for biogeographic expansion. Meanwhile, ITS1 was found to be an effective marker for tracking C. sinensis infection

  11. Low Divergence of Clonorchis sinensis in China Based on Multilocus Analysis

    Science.gov (United States)

    Sun, Jiufeng; Huang, Yan; Huang, Huaiqiu; Liang, Pei; Wang, Xiaoyun; Mao, Qiang; Men, Jingtao; Chen, Wenjun; Deng, Chuanhuan; Zhou, Chenhui; Lv, Xiaoli; Zhou, Juanjuan; Zhang, Fan; Li, Ran; Tian, Yanli; Lei, Huali; Liang, Chi; Hu, Xuchu; Xu, Jin; Li, Xuerong; XinbingYu

    2013-01-01

    Clonorchis sinensis, an ancient parasite that infects a number of piscivorous mammals, attracts significant public health interest due to zoonotic exposure risks in Asia. The available studies are insufficient to reflect the prevalence, geographic distribution, and intraspecific genetic diversity of C. sinensis in endemic areas. Here, a multilocus analysis based on eight genes (ITS1, act, tub, ef-1a, cox1, cox3, nad4 and nad5 [4.986 kb]) was employed to explore the intra-species genetic construction of C. sinensis in China. Two hundred and fifty-six C. sinensis isolates were obtained from environmental reservoirs from 17 provinces of China. A total of 254 recognized Multilocus Types (MSTs) showed high diversity among these isolates using multilocus analysis. The comparison analysis of nuclear and mitochondrial phylogeny supports separate clusters in a nuclear dendrogram. Genetic differentiation analysis of three clusters (A, B, and C) showed low divergence within populations. Most isolates from clusters B and C are geographically limited to central China, while cluster A is extraordinarily genetically diverse. Further genetic analyses between different geographic distributions, water bodies and hosts support the low population divergence. The latter haplotype analyses were consistent with the phylogenetic and genetic differentiation results. A recombination network based on concatenated sequences showed a concentrated linkage recombination population in cox1, cox3, nad4 and nad5, with spatial structuring in ITS1. Coupled with the history record and archaeological evidence of C. sinensis infection in mummified desiccated feces, these data point to an ancient origin of C. sinensis in China. In conclusion, we present a likely phylogenetic structure of the C. sinensis population in mainland China, highlighting its possible tendency for biogeographic expansion. Meanwhile, ITS1 was found to be an effective marker for tracking C. sinensis infection worldwide. Thus, the

  12. Growth divergence: a challenging opportunity for dendrochronology

    Science.gov (United States)

    Buras, Allan; Sass-Klaassen, Ute; Wilmking, Martin

    2017-04-01

    Dendrochronology is an essential cornerstone of paleoclimatology and the evaluation of climate change impacts on forest ecosystems. However, a growing body of literature indicates that the standard dendrochronological approach may too rigorously neglect individualistic tree-growth (e.g. Wilmking et al., 2004, Buras et al., 2016). Amongst others, these studies showed convincing evidence that individual trees of the same species sampled at one site expressed different long-term growth patterns and therefore differing climate-growth relationships. This phenomenon is commonly termed growth divergence (GD) and possibly weakens our ability to correctly estimate past climate variability as discussed in the context of the so-called divergence phenomenon (D'Arrigo et al., 2008). In this context, climate change may naturally select for trees on the stand-level which are better adapted to future conditions. Although GD has been reported for several sites, the standard dendrochronological approach yet does not consider the existence of GD. A possible reason for this methodological persistence is the lack of detailed information on the frequency, magnitude, and impact of GD occurrence. To assess GD occurrence and related tree-individual variations in climate-growth response we conducted a global GD study by using 134 ring-width data representing 52 tree species and 16 genera distributed over 115 sites across 22 countries. Our analyses clearly reveal GD to be a common phenomenon as occurring in 85 % of all sites. GD was clearly related to the degree of tree-individual differences in climate-growth response. Respective transfer functions which appropriately accounted for GD by selection of tree-cohorts with a high share of long-term variance on average increased the precision and stability of tree-ring based climate reconstructions. Concluding, incorporation of GD assessments into the dendrochronological approach has a strong potential to improve the precision of our predictions

  13. Mining environmental high-throughput sequence data sets to identify divergent amplicon clusters for phylogenetic reconstruction and morphotype visualization.

    Science.gov (United States)

    Gimmler, Anna; Stoeck, Thorsten

    2015-08-01

    Environmental high-throughput sequencing (envHTS) is a very powerful tool, which in protistan ecology is predominantly used for the exploration of diversity and its geographic and local patterns. We here used a pyrosequenced V4-SSU rDNA data set from a solar saltern pond as test case to exploit such massive protistan amplicon data sets beyond this descriptive purpose. Therefore, we combined a Swarm-based blastn network including 11 579 ciliate V4 amplicons to identify divergent amplicon clusters with targeted polymerase chain reaction (PCR) primer design for full-length small subunit of the ribosomal DNA retrieval and probe design for fluorescence in situ hybridization (FISH). This powerful strategy allows to benefit from envHTS data sets to (i) reveal the phylogenetic position of the taxon behind divergent amplicons; (ii) improve phylogenetic resolution and evolutionary history of specific taxon groups; (iii) solidly assess an amplicons (species') degree of similarity to its closest described relative; (iv) visualize the morphotype behind a divergent amplicons cluster; (v) rapidly FISH screen many environmental samples for geographic/habitat distribution and abundances of the respective organism and (vi) to monitor the success of enrichment strategies in live samples for cultivation and isolation of the respective organisms. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  14. Dendritic cells pulsed with Pythium insidiosum (1,3)(1,6)-β-glucan, Heat-inactivated zoospores and immunotherapy prime naïve T cells to Th1 differentiation in vitro.

    Science.gov (United States)

    Ledur, Pauline C; Tondolo, Juliana S M; Jesus, Francielli P K; Verdi, Camila M; Loreto, Érico S; Alves, Sydney H; Santurio, Janio M

    2018-03-01

    Pythiosis is a life-threatening disease caused by the fungus-like microorganism Pythium insidiosum that can lead to death if not treated. Since P. insidiosum has particular cell wall characteristics, pythiosis is difficult to treat, as it does not respond well to traditional antifungal drugs. In our study, we investigated a new immunotherapeutic approach with potential use in treatment and in the acquisition of immunity against pythiosis. Dendritic cells from both human and mouse, pulsed with P. insidiosum heat-inactivated zoospore, (1,3)(1,6)-β-glucan and the immunotherapeutic PitiumVac ® efficiently induced naïve T cell differentiation in a Th1 phenotype by the activation of specific Th1 cytokine production in vitro. Heat-inactivated zoospores showed the greatest Th1 response among the tested groups, with a significant increase in IL-6 and IFN-γ production in human cells. In mice cells, we also observed a Th17 pathway induction, with an increase on the IL-17A levels in lymphocytes cultured with β-glucan pulsed DCs. These results suggest a potential use of DCs pulsed with P. insidiosum antigens as a new therapeutic strategy in the treatment and acquisition of immunity against pythiosis. Copyright © 2017 Elsevier GmbH. All rights reserved.

  15. A Separation between Divergence and Holevo Information for Ensembles

    OpenAIRE

    Jain, Rahul; Nayak, Ashwin; Su, Yi

    2007-01-01

    The notion of divergence information of an ensemble of probability distributions was introduced by Jain, Radhakrishnan, and Sen in the context of the ``substate theorem''. Since then, divergence has been recognized as a more natural measure of information in several situations in quantum and classical communication. We construct ensembles of probability distributions for which divergence information may be significantly smaller than the more standard Holevo information. As a result, we establ...

  16. Exact cancellation of quadratic divergences in top condensation models

    International Nuclear Information System (INIS)

    Blumhofer, A.

    1995-01-01

    We discuss the hierarchy problem and the corresponding quadratic divergences in the top mode Standard Model. Quadratic divergences appear at each order 1/N c since fermionic and bosonic contributions are of different order 1/N c . It is shown that the full dynamical system to all orders in 1/N c admits a solution, where the sum of all quadratic divergent contributions disappears. ((orig.))

  17. Culturally divergent responses to mortality salience.

    Science.gov (United States)

    Ma-Kellams, Christine; Blascovich, Jim

    2011-08-01

    Two experiments compared the effects of death thoughts, or mortality salience, on European and Asian Americans. Research on terror management theory has demonstrated that in Western cultural groups, individuals typically employ self-protective strategies in the face of death-related thoughts. Given fundamental East-West differences in self-construal (i.e., the independent vs. interdependent self), we predicted that members of Eastern cultural groups would affirm other people, rather than defend and affirm the self, after encountering conditions of mortality salience. We primed European Americans and Asian Americans with either a death or a control prime and examined the effect of this manipulation on attitudes about a person who violates cultural norms (Study 1) and on attributions about the plight of an innocent victim (Study 2). Mortality salience promoted culturally divergent responses, leading European Americans to defend the self and Asian Americans to defend other people.

  18. Process model simulations of the divergence effect

    Science.gov (United States)

    Anchukaitis, K. J.; Evans, M. N.; D'Arrigo, R. D.; Smerdon, J. E.; Hughes, M. K.; Kaplan, A.; Vaganov, E. A.

    2007-12-01

    We explore the extent to which the Vaganov-Shashkin (VS) model of conifer tree-ring formation can explain evidence for changing relationships between climate and tree growth over recent decades. The VS model is driven by daily environmental forcing (temperature, soil moisture, and solar radiation), and simulates tree-ring growth cell-by-cell as a function of the most limiting environmental control. This simplified representation of tree physiology allows us to examine using a selection of case studies whether instances of divergence may be explained in terms of changes in limiting environmental dependencies or transient climate change. Identification of model-data differences permits further exploration of the effects of tree-ring standardization, atmospheric composition, and additional non-climatic factors.

  19. Hamiltonian mechanics and divergence-free fields

    International Nuclear Information System (INIS)

    Boozer, A.H.

    1986-08-01

    The field lines, or integral curves, of a divergence-free field in three dimensions are shown to be topologically equivalent to the trajectories of a Hamiltonian with two degrees of freedom. The consideration of fields that depend on a parameter allow the construction of a canonical perturbation theory which is valid even if the perturbation is large. If the parametric dependence of the magnetic, or the vorticity field is interpreted as time dependence, evolution equations are obtained which give Kelvin's theorem or the flux conservation theorem for ideal fluids and plasmas. The Hamiltonian methods prove especially useful for study of fields in which the field lines must be known throughout a volume of space

  20. Some Divergence Properties of Asset Price Models

    Directory of Open Access Journals (Sweden)

    Wolfgang Stummer

    2001-12-01

    Full Text Available Abstract: We consider asset price processes Xt which are weak solutions of one-dimensional stochastic differential equations of the form (equation (2 Such price models can be interpreted as non-lognormally-distributed generalizations of the geometric Brownian motion. We study properties of the Iα-divergence between the law of the solution Xt and the corresponding drift-less measure (the special case α=1 is the relative entropy. This will be applied to some context in statistical information theory as well as to arbitrage theory and contingent claim valuation. For instance, the seminal option pricing theorems of Black-Scholes and Merton appear as a special case.

  1. DIVERGING DISCOURSES ON THE SYR DARYA

    Directory of Open Access Journals (Sweden)

    Eelke Kraak

    2012-01-01

    Full Text Available The hydraulic mission of the Soviet Union has transformed Central Asia’s Syr Darya River into a governable entity. After the dissolution of the Soviet Union the river system disintegrated and conflict arose over the operation of the main dam and reservoir of the river: the Toktogul. Uzbekistan and Kyrgyzstan have widely different and diverging sanctioned discourses on how the dam should be operated and on the nature of the water itself. These discourses have had a significant impact on the hydro-politics of the river basin and the operation of the dam. The central argument of this paper is that both the decline of the Aral Sea, and the potential conflict between the states are driven by the same modernist governmentality of the river.

  2. Divergent clonal selection dominates medulloblastoma at recurrence

    Science.gov (United States)

    Morrissy, A. Sorana; Garzia, Livia; Shih, David J. H.; Zuyderduyn, Scott; Huang, Xi; Skowron, Patryk; Remke, Marc; Cavalli, Florence M. G.; Ramaswamy, Vijay; Lindsay, Patricia E.; Jelveh, Salomeh; Donovan, Laura K.; Wang, Xin; Luu, Betty; Zayne, Kory; Li, Yisu; Mayoh, Chelsea; Thiessen, Nina; Mercier, Eloi; Mungall, Karen L.; Ma, Yusanne; Tse, Kane; Zeng, Thomas; Shumansky, Karey; Roth, Andrew J. L.; Shah, Sohrab; Farooq, Hamza; Kijima, Noriyuki; Holgado, Borja L.; Lee, John J. Y.; Matan-Lithwick, Stuart; Liu, Jessica; Mack, Stephen C.; Manno, Alex; Michealraj, K. A.; Nor, Carolina; Peacock, John; Qin, Lei; Reimand, Juri; Rolider, Adi; Thompson, Yuan Y.; Wu, Xiaochong; Pugh, Trevor; Ally, Adrian; Bilenky, Mikhail; Butterfield, Yaron S. N.; Carlsen, Rebecca; Cheng, Young; Chuah, Eric; Corbett, Richard D.; Dhalla, Noreen; He, An; Lee, Darlene; Li, Haiyan I.; Long, William; Mayo, Michael; Plettner, Patrick; Qian, Jenny Q.; Schein, Jacqueline E.; Tam, Angela; Wong, Tina; Birol, Inanc; Zhao, Yongjun; Faria, Claudia C.; Pimentel, José; Nunes, Sofia; Shalaby, Tarek; Grotzer, Michael; Pollack, Ian F.; Hamilton, Ronald L.; Li, Xiao-Nan; Bendel, Anne E.; Fults, Daniel W.; Walter, Andrew W.; Kumabe, Toshihiro; Tominaga, Teiji; Collins, V. Peter; Cho, Yoon-Jae; Hoffman, Caitlin; Lyden, David; Wisoff, Jeffrey H.; Garvin, James H.; Stearns, Duncan S.; Massimi, Luca; Schüller, Ulrich; Sterba, Jaroslav; Zitterbart, Karel; Puget, Stephanie; Ayrault, Olivier; Dunn, Sandra E.; Tirapelli, Daniela P. C.; Carlotti, Carlos G.; Wheeler, Helen; Hallahan, Andrew R.; Ingram, Wendy; MacDonald, Tobey J.; Olson, Jeffrey J.; Van Meir, Erwin G.; Lee, Ji-Yeoun; Wang, Kyu-Chang; Kim, Seung-Ki; Cho, Byung-Kyu; Pietsch, Torsten; Fleischhack, Gudrun; Tippelt, Stephan; Ra, Young Shin; Bailey, Simon; Lindsey, Janet C.; Clifford, Steven C.; Eberhart, Charles G.; Cooper, Michael K.; Packer, Roger J.; Massimino, Maura; Garre, Maria Luisa; Bartels, Ute; Tabori, Uri; Hawkins, Cynthia E.; Dirks, Peter; Bouffet, Eric; Rutka, James T.; Wechsler-Reya, Robert J.; Weiss, William A.; Collier, Lara S.; Dupuy, Adam J.; Korshunov, Andrey; Jones, David T. W.; Kool, Marcel; Northcott, Paul A.; Pfister, Stefan M.; Largaespada, David A.; Mungall, Andrew J.; Moore, Richard A.; Jabado, Nada; Bader, Gary D.; Jones, Steven J. M.; Malkin, David; Marra, Marco A.; Taylor, Michael D.

    2016-01-01

    The development of targeted anti-cancer therapies through the study of cancer genomes is intended to increase survival rates and decrease treatment-related toxicity. We treated a transposon–driven, functional genomic mouse model of medulloblastoma with ‘humanized’ in vivo therapy (microneurosurgical tumour resection followed by multi-fractionated, image-guided radiotherapy). Genetic events in recurrent murine medulloblastoma exhibit a very poor overlap with those in matched murine diagnostic samples (sequencing of 33 pairs of human diagnostic and post-therapy medulloblastomas demonstrated substantial genetic divergence of the dominant clone after therapy (recurrence). In both mice and humans, the dominant clone at recurrence arose through clonal selection of a pre-existing minor clone present at diagnosis. Targeted therapy is unlikely to be effective in the absence of the target, therefore our results offer a simple, proximal, and remediable explanation for the failure of prior clinical trials of targeted therapy. PMID:26760213

  3. Divergence is not enough: the use of ecological niche models for the validation of taxon boundaries.

    Science.gov (United States)

    Dagnino, D; Minuto, L; Casazza, G

    2017-11-01

    Delimiting taxon boundaries is crucial for any evolutionary research and conservation regulation. In order to avoid mistaken description of species, the approach of integrative taxonomy recommends considering multidisciplinary lines of evidence, including ecology. Unfortunately, ecological data are often difficult to quantify objectively. Here we test and discuss the potential use of ecological niche models for validating taxon boundaries, using three pairs of closely related plant taxa endemic to the south-western Alps as a case study. We also discuss the application of ecological niche models for species delimitation and the implementation of different approaches. Niche overlap, niche equivalency and niche similarity were assessed both in multidimensional environmental space and in geographic space to look for differences in the niche of three pairs of closely related plant taxa. We detected a high degree of niche differentiation between taxa although this result seems not due to differences in habitat selection. The different statistical tests gave contrasting outcomes between environmental and geographic spaces. According to our results, niche divergence does not seem to support taxon boundaries at species level, but may have had important consequences for local adaptation and in generating phenotypic diversity at intraspecific level. Environmental space analysis should be preferred to geographic space as it provides more clear results. Even if the different analyses widely disagree in their conclusions about taxon boundaries, our study suggests that ecological niche models may help taxonomists to reach a decision. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  4. Ecological and Genetic Divergences with Gene Flow of Two Sister Species (Leucomeris decora and Nouelia insignis) Driving by Climatic Transition in Southwest China.

    Science.gov (United States)

    Zhao, Yujuan; Yin, Genshen; Pan, Yuezhi; Gong, Xun

    2018-01-01

    Understanding of the processes of divergence and speciation is a major task for biodiversity researches and may offer clearer insight into mechanisms generating biological diversity. Here, we employ an integrative approach to explore genetic and ecological differentiation of Leucomeris decora and Nouelia insignis distributed allopatrically along the two sides of the biogeographic boundary 'Tanaka Line' in Southwest China. We addressed these questions using ten low-copy nuclear genes and nine plastid DNA regions sequenced among individuals sampled from 28 populations across their geographic ranges in China. Phylogenetic, coalescent-based population genetic analyses, approximate Bayesian computation (ABC) framework and ecological niche models (ENMs) were conducted. We identified a closer phylogenetic relationship in maternal lineage of L. decora with N. insignis than that between L . decora and congeneric Leucomeris spectabilis . A deep divergence between the two species was observed and occurred at the boundary between later Pliocene and early Pleistocene. However, the evidence of significant chloroplast DNA gene flow was also detected between the marginal populations of L. decora and N. insignis . Niche models and statistical analyses showed significant ecological differentiation, and two nuclear loci among the ten nuclear genes may be under divergent selection. These integrative results imply that the role of climatic shift from Pliocene to Pleistocene may be the prominent factor for the divergence of L . decora and N . insignis , and population expansion after divergence may have given rise to chloroplast DNA introgression. The divergence was maintained by differential selection despite in the face of gene flow.

  5. Speciation on a local geographic scale: the evolution of a rare rock outcrop specialist in Mimulus.

    Science.gov (United States)

    Ferris, Kathleen G; Sexton, Jason P; Willis, John H

    2014-08-05

    Speciation can occur on both large and small geographical scales. In plants, local speciation, where small populations split off from a large-ranged progenitor species, is thought to be the dominant mode, yet there are still few examples to verify speciation has occurred in this manner. A recently described morphological species in the yellow monkey flowers, Mimulus filicifolius, is an excellent candidate for local speciation because of its highly restricted geographical range. Mimulus filicifolius was formerly identified as a population of M. laciniatus due to similar lobed leaf morphology and rocky outcrop habitat. To investigate whether M. filicifolius is genetically divergent and reproductively isolated from M. laciniatus, we examined patterns of genetic diversity in ten nuclear and eight microsatellite loci, and hybrid fertility in M. filicifolius and its purported close relatives: M. laciniatus, M. guttatus and M. nasutus. We found that M. filicifolius is genetically divergent from the other species and strongly reproductively isolated from M. laciniatus. We conclude that M. filicifolius is an independent rock outcrop specialist despite being morphologically and ecologically similar to M. laciniatus, and that its small geographical range nested within other wide-ranging members of the M. guttatus species complex is consistent with local speciation. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  6. Using Dendritic Heat Maps to Simultaneously Display Genotype Divergence with Phenotype Divergence.

    Science.gov (United States)

    Kellom, Matthew; Raymond, Jason

    2016-01-01

    The advancement of techniques to visualize and analyze large-scale sequencing datasets is an area of active research and is rooted in traditional techniques such as heat maps and dendrograms. We introduce dendritic heat maps that display heat map results over aligned DNA sequence clusters for a range of clustering cutoffs. Dendritic heat maps aid in visualizing the effects of group differences on clustering hierarchy and relative abundance of sampled sequences. Here, we artificially generate two separate datasets with simplified mutation and population growth procedures with GC content group separation to use as example phenotypes. In this work, we use the term phenotype to represent any feature by which groups can be separated. These sequences were clustered in a fractional identity range of 0.75 to 1.0 using agglomerative minimum-, maximum-, and average-linkage algorithms, as well as a divisive centroid-based algorithm. We demonstrate that dendritic heat maps give freedom to scrutinize specific clustering levels across a range of cutoffs, track changes in phenotype inequity across multiple levels of sequence clustering specificity, and easily visualize how deeply rooted changes in phenotype inequity are in a dataset. As genotypes diverge in sample populations, clusters are shown to break apart into smaller clusters at higher identity cutoff levels, similar to a dendrogram. Phenotype divergence, which is shown as a heat map of relative abundance bin response, may or may not follow genotype divergences. This joined view highlights the relationship between genotype and phenotype divergence for treatment groups. We discuss the minimum-, maximum-, average-, and centroid-linkage algorithm approaches to building dendritic heat maps and make a case for the divisive "top-down" centroid-based clustering methodology as being the best option visualize the effects of changing factors on clustering hierarchy and relative abundance.

  7. Using Dendritic Heat Maps to Simultaneously Display Genotype Divergence with Phenotype Divergence.

    Directory of Open Access Journals (Sweden)

    Matthew Kellom

    Full Text Available The advancement of techniques to visualize and analyze large-scale sequencing datasets is an area of active research and is rooted in traditional techniques such as heat maps and dendrograms. We introduce dendritic heat maps that display heat map results over aligned DNA sequence clusters for a range of clustering cutoffs. Dendritic heat maps aid in visualizing the effects of group differences on clustering hierarchy and relative abundance of sampled sequences. Here, we artificially generate two separate datasets with simplified mutation and population growth procedures with GC content group separation to use as example phenotypes. In this work, we use the term phenotype to represent any feature by which groups can be separated. These sequences were clustered in a fractional identity range of 0.75 to 1.0 using agglomerative minimum-, maximum-, and average-linkage algorithms, as well as a divisive centroid-based algorithm. We demonstrate that dendritic heat maps give freedom to scrutinize specific clustering levels across a range of cutoffs, track changes in phenotype inequity across multiple levels of sequence clustering specificity, and easily visualize how deeply rooted changes in phenotype inequity are in a dataset. As genotypes diverge in sample populations, clusters are shown to break apart into smaller clusters at higher identity cutoff levels, similar to a dendrogram. Phenotype divergence, which is shown as a heat map of relative abundance bin response, may or may not follow genotype divergences. This joined view highlights the relationship between genotype and phenotype divergence for treatment groups. We discuss the minimum-, maximum-, average-, and centroid-linkage algorithm approaches to building dendritic heat maps and make a case for the divisive "top-down" centroid-based clustering methodology as being the best option visualize the effects of changing factors on clustering hierarchy and relative abundance.

  8. Bathymetric and geographic population structure in the pan-Atlantic deep-sea bivalve Deminucula atacellana (Schenck, 1939).

    Science.gov (United States)

    Zardus, John D; Etter, Ron J; Chase, Michael R; Rex, Michael A; Boyle, Elizabeth E

    2006-03-01

    The deep-sea soft-sediment environment hosts a diverse and highly endemic fauna of uncertain origin. We know little about how this fauna evolved because geographic patterns of genetic variation, the essential information for inferring patterns of population differentiation and speciation are poorly understood. Using formalin-fixed specimens from archival collections, we quantify patterns of genetic variation in the protobranch bivalve Deminucula atacellana, a species widespread throughout the Atlantic Ocean at bathyal and abyssal depths. Samples were taken from 18 localities in the North American, West European and Argentine basins. A hypervariable region of mitochondrial 16S rDNA was amplified by polymerase chain reaction (PCR) and sequenced from 130 individuals revealing 21 haplotypes. Except for several important exceptions, haplotypes are unique to each basin. Overall gene diversity is high (h = 0.73) with pronounced population structure (Phi(ST) = 0.877) and highly significant geographic associations (P < 0.0001). Sequences cluster into four major clades corresponding to differences in geography and depth. Genetic divergence was much greater among populations at different depths within the same basin, than among those at similar depths but separated by thousands of kilometres. Isolation by distance probably explains much of the interbasin variation. Depth-related divergence may reflect historical patterns of colonization or strong environmental selective gradients. Broadly distributed deep-sea organisms can possess highly genetically divergent populations, despite the lack of any morphological divergence.

  9. Representations built from a true geographic database

    DEFF Research Database (Denmark)

    Bodum, Lars

    2005-01-01

    the whole world in 3d and with a spatial reference given by geographic coordinates. Built on top of this is a customised viewer, based on the Xith(Java) scenegraph. The viewer reads the objects directly from the database and solves the question about Level-Of-Detail on buildings, orientation in relation...... a representation based on geographic and geospatial principles. The system GRIFINOR, developed at 3DGI, Aalborg University, DK, is capable of creating this object-orientation and furthermore does this on top of a true Geographic database. A true Geographic database can be characterized as a database that can cover...

  10. The Oklahoma Geographic Information Retrieval System

    Science.gov (United States)

    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.

  11. CONTEMPORARY TRENDS IN GEOGRAPHICAL EDUCATION

    Directory of Open Access Journals (Sweden)

    M. Wasileva

    2017-01-01

    Full Text Available The geography includes rich, diverse and comprehensive themes that give us an understanding of our changing environment and interconnected world. It includes the study of the physical environment and resources; cultures, economies and societies; people and places; and global development and civic participation. As a subject, geography is particularly valuable because it provides information for exploring contemporary issues from a different perspective. This geographical information affects us all at work and in our daily lives and helps us make informed decisions that shape our future. All these facts result in a wide discussion on many topical issues in contemporary geography didactics. Subjects of research are the new geography and economics curriculum as well as construction of modern learning process. The paper presents briefly some of the current trends and key issues of geodidactics. As central notions we consider and analyze the training/educational goals, geography curriculum, target groups and environment of geography training, training methods as well as the information sources used in geography education. We adhere that all the above-mentioned finds its reflection in planning, analysis and assessment of education and thus in its quality and effectiveness.

  12. Conformal anomaly and elimination of infrared divergences in curved spacetime

    International Nuclear Information System (INIS)

    Grib, A.A.; Nesteruk, A.V.; Pritomanov, S.A.

    1984-01-01

    The relation between the problem of eliminating the infrared divergences and the conformal anomaly of the regularized energy-momentum tensor is studied in homogeneous isotropic and anisotropic spacetime. It is shown that elimination of the infrared divergence by means of a cutoff or the introduction of a conformally invariant mass of the field leads to the absence of the conformal anomaly

  13. Performance analysis of alpha divergence in nonnegative matrix ...

    African Journals Online (AJOL)

    This is achieved by using a suitable cost function to determine the optimal factorization. Most work in this field has focused on the use of Euclidean and Kullback-Liebler (KL) divergence. This study looks into the use of α-divergence based non negative factorization in the context of single channel musical sound separation.

  14. Convergent and Divergent Thinking in the Context of Narrative Mysteries

    Science.gov (United States)

    Wenzel, William G.; Gerrig, Richard J.

    2015-01-01

    This project demonstrates how narrative mysteries provide a context in which readers engage in creative cognition. Drawing on the concepts of convergent and divergent thinking, we wrote stories that had either convergent or divergent outcomes. For example, one story had a character give his girlfriend a ring (a convergent outcome), whereas the…

  15. Transcriptome-wide patterns of divergence during allopatric evolution.

    Science.gov (United States)

    Pereira, Ricardo J; Barreto, Felipe S; Pierce, N Tessa; Carneiro, Miguel; Burton, Ronald S

    2016-04-01

    Recent studies have revealed repeated patterns of genomic divergence associated with species formation. Such patterns suggest that natural selection tends to target a set of available genes, but is also indicative that closely related taxa share evolutionary constraints that limit genetic variability. Studying patterns of genomic divergence among populations within the same species may shed light on the underlying evolutionary processes. Here, we examine transcriptome-wide divergence and polymorphism in the marine copepod Tigriopus californicus, a species where allopatric evolution has led to replicate sets of populations with varying degrees of divergence and hybrid incompatibility. Our analyses suggest that relatively small effective population sizes have resulted in an exponential decline of shared polymorphisms during population divergence and also facilitated the fixation of slightly deleterious mutations within allopatric populations. Five interpopulation comparisons at three different stages of divergence show that nonsynonymous mutations tend to accumulate in a specific set of proteins. These include proteins with central roles in cellular metabolism, such as those encoded in mtDNA, but also include an additional set of proteins that repeatedly show signatures of positive selection during allopatric divergence. Although our results are consistent with a contribution of nonadaptive processes, such as genetic drift and gene expression levels, generating repeatable patterns of genomic divergence in closely related taxa, they also indicate that adaptive evolution targeting a specific set of genes contributes to this pattern. Our results yield insights into the predictability of evolution at the gene level. © 2016 John Wiley & Sons Ltd.

  16. Ultraviolet divergences in 1/N expansions of quantum field theories

    International Nuclear Information System (INIS)

    Rim, C.

    1984-01-01

    For asymptotically free theories, ultraviolet divergencies computed in 1/N expansion with dimensional regularization reduces to simple poles plus powers of Inelement of or finite terms. All divergences are determined by the two loop perturbative renormalization group functions. In an infrared free theory, however, element of = 0 becomes an essential singularity in the 1/N expansion

  17. Multiloop divergences in the closed bosonic string theory

    International Nuclear Information System (INIS)

    Gava, E.; Iengo, R.; Jayaraman, T.; Ramachandran, R.

    1985-12-01

    We discuss the structure of the divergences in the multiloop vacuum diagrams for the closed bosonic strings in the framework of the Polyakov covariant formalism. We find, by an explicit computation, that all the divergences in the theory may be interpreted as due to tadpole diagrams in which the dilation goes into the vacuum. (author)

  18. Evidence of multiple divergent mitochondrial lineages within the ...

    African Journals Online (AJOL)

    On this basis, the mitochondrial cytochrome c oxidase subunit 1 (COI) was used to reconstruct the phylogeny of Bicoxidens and reveal divergent lineages within the genus. Maximum likelihood and Bayesian inference analyses recovered a paraphyletic Bicoxidens phylogram with divergent lineages present in three species ...

  19. Vorticity and divergence in the high-latitude upper thermosphere

    International Nuclear Information System (INIS)

    Thayer, J.P.; Killeen, T.L.

    1991-01-01

    Measurements made from the Dynamics Explorer-2 satellite in November 1981 through January 1982 and November 1982 through January 1983 have been analyzed to determine the divergence and vertical component of vorticity of the high-latitude neutral wind field in the upper thermosphere for quiet (kp≤6) geomagnetic conditions and for both northern (winter) and southern (summer) hemispheres in the polar thermosphere and provides insight into the relative strengths of the different sources of momentum and energy responsible for driving the winds. The principal findings from this work include the following: The mean neutral wind pattern is dominated by rotational flow rather than by divergent flow, with a typical vorticity: divergence ratio of ∼ 2:1 for active conditions and ∼ 4:1 for quiet conditions. Comparison of the divergence and vorticity patterns for quiet and active conditions indicates that the divergent component of the neutral flow intensifies more significantly with increasing geomagnetic activity than does the rotational component

  20. Escort entropies and divergences and related canonical distribution

    International Nuclear Information System (INIS)

    Bercher, J.-F.

    2011-01-01

    We discuss two families of two-parameter entropies and divergences, derived from the standard Renyi and Tsallis entropies and divergences. These divergences and entropies are found as divergences or entropies of escort distributions. Exploiting the nonnegativity of the divergences, we derive the expression of the canonical distribution associated to the new entropies and a observable given as an escort-mean value. We show that this canonical distribution extends, and smoothly connects, the results obtained in nonextensive thermodynamics for the standard and generalized mean value constraints. -- Highlights: → Two-parameter entropies are derived from q-entropies and escort distributions. → The related canonical distribution is derived. → This connects and extends known results in nonextensive statistics.

  1. One-loop divergences in the quantum theory of supergravity

    International Nuclear Information System (INIS)

    Nieuwenhuizen, P. van; Vermaseren, J.A.M.

    1976-01-01

    Supergravity does not lead to a finite quantum theory of gravitation when coupled to the spin 1, 1/2 matter multiplet. The S-matrix of photon-photon scattering diverges; its divergences are proportional to the square of the photon energy-momentum tensor, in agreement with electro-magnetic duality and chiral invariance. The graviton self-energy corrections are divergent in pure supergravity as well as in the coupled Maxwell-Einstein system and satisfy their Ward identity because the supersymmetry ghost field is commuting. The photon-graviton vertex corrections diverge, as expected from the non-invariance of the action under local scale transformations, and satisfy the equivalence principle at the quantum level. The photon self-energy is divergent. (Auth.)

  2. Active learning for noisy oracle via density power divergence.

    Science.gov (United States)

    Sogawa, Yasuhiro; Ueno, Tsuyoshi; Kawahara, Yoshinobu; Washio, Takashi

    2013-10-01

    The accuracy of active learning is critically influenced by the existence of noisy labels given by a noisy oracle. In this paper, we propose a novel pool-based active learning framework through robust measures based on density power divergence. By minimizing density power divergence, such as β-divergence and γ-divergence, one can estimate the model accurately even under the existence of noisy labels within data. Accordingly, we develop query selecting measures for pool-based active learning using these divergences. In addition, we propose an evaluation scheme for these measures based on asymptotic statistical analyses, which enables us to perform active learning by evaluating an estimation error directly. Experiments with benchmark datasets and real-world image datasets show that our active learning scheme performs better than several baseline methods. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Geographical National Condition and Complex System

    Directory of Open Access Journals (Sweden)

    WANG Jiayao

    2016-01-01

    Full Text Available The significance of studying the complex system of geographical national conditions lies in rationally expressing the complex relationships of the “resources-environment-ecology-economy-society” system. Aiming to the problems faced by the statistical analysis of geographical national conditions, including the disunity of research contents, the inconsistency of range, the uncertainty of goals, etc.the present paper conducted a range of discussions from the perspectives of concept, theory and method, and designed some solutions based on the complex system theory and coordination degree analysis methods.By analyzing the concepts of geographical national conditions, geographical national conditions survey and geographical national conditions statistical analysis, as well as investigating the relationships between theirs, the statistical contents and the analytical range of geographical national conditions are clarified and defined. This investigation also clarifies the goals of the statistical analysis by analyzing the basic characteristics of the geographical national conditions and the complex system, and the consistency between the analysis of the degree of coordination and statistical analyses. It outlines their goals, proposes a concept for the complex system of geographical national conditions, and it describes the concept. The complex system theory provides new theoretical guidance for the statistical analysis of geographical national conditions. The degree of coordination offers new approaches on how to undertake the analysis based on the measurement method and decision-making analysis scheme upon which the complex system of geographical national conditions is based. It analyzes the overall trend via the degree of coordination of the complex system on a macro level, and it determines the direction of remediation on a micro level based on the degree of coordination among various subsystems and of single systems. These results establish

  4. Mitochondrial and nuclear sequence polymorphisms reveal geographic structuring in Amazonian populations of Echinococcus vogeli (Cestoda: Taeniidae).

    Science.gov (United States)

    Santos, Guilherme B; Soares, Manoel do C P; de F Brito, Elisabete M; Rodrigues, André L; Siqueira, Nilton G; Gomes-Gouvêa, Michele S; Alves, Max M; Carneiro, Liliane A; Malheiros, Andreza P; Póvoa, Marinete M; Zaha, Arnaldo; Haag, Karen L

    2012-12-01

    To date, nothing is known about the genetic diversity of the Echinococcus neotropical species, Echinococcus vogeli and Echinococcus oligarthrus. Here we used mitochondrial and nuclear DNA sequence polymorphisms to uncover the genetic structure, transmission and history of E. vogeli in the Brazilian Amazon, based on a sample of 38 isolates obtained from human and wild animal hosts. We confirm that the parasite is partially synanthropic and show that its populations are diverse. Furthermore, significant geographical structuring is found, with western and eastern populations being genetically divergent. Copyright © 2012 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  5. On the geographical differentiation of Gymnodactylus geckoides Spix, 1825 (Sauria, Gekkonidae: speciation in the Brasilian caatingas

    Directory of Open Access Journals (Sweden)

    Vanzolini Paulo Emilio

    2004-01-01

    Full Text Available The specific concept of G. geckoides was initially ascertained based on a topotypical sample from Salvador, Bahia. Geographic differentiation was studied through the analysis of two meristic characters (tubercles in a paramedian row and fourth toe lamellae and color pattern of 327 specimens from 23 localities. It is shown that the population from the southernmost locality, Mucugê, is markedly divergent in all characters studied. A Holocene refuge model is proposed to explain the pattern. A decision about the rank to be attributed to the Mucugê population is deferred until more detailed sampling is effected and molecular methods are applied.

  6. Divergent mortality trends by ethnicity in Fiji.

    Science.gov (United States)

    Taylor, Richard; Carter, Karen; Naidu, Shivnay; Linhart, Christine; Azim, Syed; Rao, Chalapati; Lopez, Alan D

    2013-12-01

    To examine trends in infant mortality rate (IMR), adult mortality and life expectancy (LE) in the two major Fijian ethnic groups since 1975. Estimates of IMR, adult mortality (15-59 years) and LE by ethnicity are calculated from previously unreported Fiji Ministry of Health data and extracted from published sources. Over 1975-2008: IMR decreased from 33 to 20 deaths/1,000 live births in i-Taukei (Fiji Melanesians); and 38 to 18 in Fijians of Indian descent. Increased adult male mortality among i-Taukei and decline among Fijians of Indian descent led to an equal probability of dying in 2007 of 29%; while in female adults the probability trended upwards in i-Taukei to 25%, and declined in Fijians of Indian descent to 17%. Life expectancy in both ethnicities increased until 1985 (to 64 years for males; 68 for females) then forming a plateau in males of both ethnicities, and Fijian females of Indian descent, but declining in i-Taukei females to 66 years in 2007. Despite IMR declines over 1975-2008, LE for i-Taukei and Fijians of Indian descent has not increased since 1985, and has actually decreased in i-Taukei women, consistent with trends in adult mortality (15-59 years). Mortality analyses in Fiji that consider the entire population mask divergent trends in the major ethnic groups. This situation is most likely a consequence of non-communicable disease mortality, requiring further assessment and a strengthened response.

  7. On the divergences of inflationary superhorizon perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Enqvist, K; Nurmi, S [Physics Department, University of Helsinki, PO Box 64, Helsinki, FIN-00014 (Finland); Podolsky, D; Rigopoulos, G I, E-mail: kari.enqvist@helsinki.fi, E-mail: sami.nurmi@helsinki.fi, E-mail: dmitry.podolsky@helsinki.fi, E-mail: gerasimos.rigopoulos@helsinki.fi [Helsinki Institute of Physics, University of Helsinki, PO Box 64, Helsinki, FIN-00014 (Finland)

    2008-04-15

    We discuss the infrared divergences that appear to plague cosmological perturbation theory. We show that, within the stochastic framework, they are regulated by eternal inflation so that the theory predicts finite fluctuations. Using the {Delta}N formalism to one loop, we demonstrate that the infrared modes can be absorbed into additive constants and the coefficients of the diagrammatic expansion for the connected parts of two-and three-point functions of the curvature perturbation. As a result, the use of any infrared cutoff below the scale of eternal inflation is permitted, provided that the background fields are appropriately redefined. The natural choice for the infrared cutoff would, of course, be the present horizon; other choices manifest themselves in the running of the correlators. We also demonstrate that it is possible to define observables that are renormalization-group-invariant. As an example, we derive a non-perturbative, infrared finite and renormalization point-independent relation between the two-point correlators of the curvature perturbation for the case of the free single field.

  8. Remarkable ancient divergences amongst neglected lorisiform primates

    Science.gov (United States)

    Nekaris, K. Anne‐Isola; Perkin, Andrew; Bearder, Simon K.; Pimley, Elizabeth R.; Schulze, Helga; Streicher, Ulrike; Nadler, Tilo; Kitchener, Andrew; Zischler, Hans; Zinner, Dietmar; Roos, Christian

    2015-01-01

    Lorisiform primates (Primates: Strepsirrhini: Lorisiformes) represent almost 10% of the living primate species and are widely distributed in sub‐Saharan Africa and South/South‐East Asia; however, their taxonomy, evolutionary history, and biogeography are still poorly understood. In this study we report the largest molecular phylogeny in terms of the number of represented taxa. We sequenced the complete mitochondrial cytochrome b gene for 86 lorisiform specimens, including ∼80% of all the species currently recognized. Our results support the monophyly of the Galagidae, but a common ancestry of the Lorisinae and Perodicticinae (family Lorisidae) was not recovered. These three lineages have early origins, with the Galagidae and the Lorisinae diverging in the Oligocene at about 30 Mya and the Perodicticinae emerging in the early Miocene. Our mitochondrial phylogeny agrees with recent studies based on nuclear data, and supports Euoticus as the oldest galagid lineage and the polyphyletic status of Galagoides. Moreover, we have elucidated phylogenetic relationships for several species never included before in a molecular phylogeny. The results obtained in this study suggest that lorisiform diversity remains substantially underestimated and that previously unnoticed cryptic diversity might be present within many lineages, thus urgently requiring a comprehensive taxonomic revision of this primate group. © 2015 The Linnean Society of London PMID:26900177

  9. Conceptual Model of Dynamic Geographic Environment

    Directory of Open Access Journals (Sweden)

    Martínez-Rosales Miguel Alejandro

    2014-04-01

    Full Text Available In geographic environments, there are many and different types of geographic entities such as automobiles, trees, persons, buildings, storms, hurricanes, etc. These entities can be classified into two groups: geographic objects and geographic phenomena. By its nature, a geographic environment is dynamic, thus, it’s static modeling is not sufficient. Considering the dynamics of geographic environment, a new type of geographic entity called event is introduced. The primary target is a modeling of geographic environment as an event sequence, because in this case the semantic relations are much richer than in the case of static modeling. In this work, the conceptualization of this model is proposed. It is based on the idea to process each entity apart instead of processing the environment as a whole. After that, the so called history of each entity and its spatial relations to other entities are defined to describe the whole environment. The main goal is to model systems at a conceptual level that make use of spatial and temporal information, so that later it can serve as the semantic engine for such systems.

  10. 25 CFR 571.10 - Geographical location.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Geographical location. 571.10 Section 571.10 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR COMPLIANCE AND ENFORCEMENT PROVISIONS MONITORING AND INVESTIGATIONS Subpoenas and Depositions § 571.10 Geographical location. The attendance of...

  11. The evolution of cooperation on geographical networks

    Science.gov (United States)

    Li, Yixiao; Wang, Yi; Sheng, Jichuan

    2017-11-01

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

  12. Hierarchical spatial organization of geographical networks

    International Nuclear Information System (INIS)

    Travencolo, Bruno A N; Costa, Luciano da F

    2008-01-01

    In this work, we propose a hierarchical extension of the polygonality index as the means to characterize geographical planar networks. By considering successive neighborhoods around each node, it is possible to obtain more complete information about the spatial order of the network at progressive spatial scales. The potential of the methodology is illustrated with respect to synthetic and real geographical networks

  13. Future Prospects for Geographical Education in Slovenia

    Science.gov (United States)

    Resnic Planinc, Tatjana

    2011-01-01

    This paper deals with future prospects for geographical education in Slovenia, with special emphasis on the development and aims of the didactics of geography. The author discusses the past development of geographical curricula and of competencies of geography teachers, and the education of future teachers of the subject in Slovenia. Her ideas are…

  14. Socioeconomic Development Inequalities among Geographic Units ...

    African Journals Online (AJOL)

    Socio-economic development inequality among geographic units is a phenomenon common in both the developed and developing countries. Regional inequality may result in dissension among geographic units of the same state due to the imbalance in socio-economic development. This study examines the inequality ...

  15. Genetic structure and divergence in populations of Lutzomyia cruciata, a phlebotomine sand fly (Diptera: Psychodidae) vector of Leishmania mexicana in southeastern Mexico.

    Science.gov (United States)

    Pech-May, Angélica; Marina, Carlos F; Vázquez-Domínguez, Ella; Berzunza-Cruz, Miriam; Rebollar-Téllez, Eduardo A; Narváez-Zapata, José A; Moo-Llanes, David; Ibáñez-Bernal, Sergio; Ramsey, Janine M; Becker, Ingeborg

    2013-06-01

    The low dispersal capacity of sand flies could lead to population isolation due to geographic barriers, climate variation, or to population fragmentation associated with specific local habitats due to landscape modification. The phlebotomine sand fly Lutzomyia cruciata has a wide distribution throughout Mexico and is a vector of Leishmania mexicana in the southeast. The aim of this study was to evaluate the genetic diversity, structure, and divergence within and among populations of Lu. cruciata in the state of Chiapas, and to infer the intra-specific phylogeny using the 3' end of the mitochondrial cytochrome b gene. We analyzed 62 sequences from four Lu. cruciata populations and found 26 haplotypes, high genetic differentiation and restricted gene flow among populations (Fst=0.416, Nm=0.701, p<0.001). The highest diversity values were recorded in populations from Loma Bonita and Guadalupe Miramar. Three lineages (100% bootstrap and 7% overall divergence) were identified using a maximum likelihood phylogenetic analysis which showed high genetic divergence (17.2-22.7%). A minimum spanning haplotype network also supported separation into three lineages. Genetic structure and divergence within and among Lu. cruciata populations are hence affected by geographic heterogeneity and evolutionary background. Data obtained in the present study suggest that Lu. cruciata in the state of Chiapas consists of at least three lineages. Such findings may have implications for vector capacity and hence for vector control strategies. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Composing Models of Geographic Physical Processes

    Science.gov (United States)

    Hofer, Barbara; Frank, Andrew U.

    Processes are central for geographic information science; yet geographic information systems (GIS) lack capabilities to represent process related information. A prerequisite to including processes in GIS software is a general method to describe geographic processes independently of application disciplines. This paper presents such a method, namely a process description language. The vocabulary of the process description language is derived formally from mathematical models. Physical processes in geography can be described in two equivalent languages: partial differential equations or partial difference equations, where the latter can be shown graphically and used as a method for application specialists to enter their process models. The vocabulary of the process description language comprises components for describing the general behavior of prototypical geographic physical processes. These process components can be composed by basic models of geographic physical processes, which is shown by means of an example.

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

    Directory of Open Access Journals (Sweden)

    Agnus M. Kim

    2016-07-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    2017-08-16

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

  19. Divergence within and among Seaweed Siblings (Fucus vesiculosus and F. radicans) in the Baltic Sea.

    Science.gov (United States)

    Ardehed, Angelica; Johansson, Daniel; Sundqvist, Lisa; Schagerström, Ellen; Zagrodzka, Zuzanna; Kovaltchouk, Nikolaj A; Bergström, Lena; Kautsky, Lena; Rafajlovic, Marina; Pereyra, Ricardo T; Johannesson, Kerstin

    2016-01-01

    Closely related taxa provide significant case studies for understanding evolution of new species but may simultaneously challenge species identification and definition. In the Baltic Sea, two dominant and perennial brown algae share a very recent ancestry. Fucus vesiculosus invaded this recently formed postglacial sea 8000 years ago and shortly thereafter Fucus radicans diverged from this lineage as an endemic species. In the Baltic Sea both species reproduce sexually but also recruit fully fertile new individuals by asexual fragmentation. Earlier studies have shown local differences in morphology and genetics between the two taxa in the northern and western Bothnian Sea, and around the island of Saaremaa in Estonia, but geographic patterns seem in conflict with a single origin of F. radicans. To investigate the relationship between northern and Estonian distributions, we analysed the genetic variation using 9 microsatellite loci in populations from eastern Bothnian Sea, Archipelago Sea and the Gulf of Finland. These populations are located in between earlier studied populations. However, instead of bridging the disparate genetic gap between N-W Bothnian Sea and Estonia, as expected from a simple isolation-by-distance model, the new populations substantially increased overall genetic diversity and showed to be strongly divergent from the two earlier analysed regions, showing signs of additional distinct populations. Contrasting earlier findings of increased asexual recruitment in low salinity in the Bothnian Sea, we found high levels of sexual reproduction in some of the Gulf of Finland populations that inhabit extremely low salinity. The new data generated in this study supports the earlier conclusion of two reproductively isolated but very closely related species. However, the new results also add considerable genetic and morphological complexity within species. This makes species separation at geographic scales more demanding and suggests a need for more

  20. Divergence within and among Seaweed Siblings (Fucus vesiculosus and F. radicans in the Baltic Sea.

    Directory of Open Access Journals (Sweden)

    Angelica Ardehed

    Full Text Available Closely related taxa provide significant case studies for understanding evolution of new species but may simultaneously challenge species identification and definition. In the Baltic Sea, two dominant and perennial brown algae share a very recent ancestry. Fucus vesiculosus invaded this recently formed postglacial sea 8000 years ago and shortly thereafter Fucus radicans diverged from this lineage as an endemic species. In the Baltic Sea both species reproduce sexually but also recruit fully fertile new individuals by asexual fragmentation. Earlier studies have shown local differences in morphology and genetics between the two taxa in the northern and western Bothnian Sea, and around the island of Saaremaa in Estonia, but geographic patterns seem in conflict with a single origin of F. radicans. To investigate the relationship between northern and Estonian distributions, we analysed the genetic variation using 9 microsatellite loci in populations from eastern Bothnian Sea, Archipelago Sea and the Gulf of Finland. These populations are located in between earlier studied populations. However, instead of bridging the disparate genetic gap between N-W Bothnian Sea and Estonia, as expected from a simple isolation-by-distance model, the new populations substantially increased overall genetic diversity and showed to be strongly divergent from the two earlier analysed regions, showing signs of additional distinct populations. Contrasting earlier findings of increased asexual recruitment in low salinity in the Bothnian Sea, we found high levels of sexual reproduction in some of the Gulf of Finland populations that inhabit extremely low salinity. The new data generated in this study supports the earlier conclusion of two reproductively isolated but very closely related species. However, the new results also add considerable genetic and morphological complexity within species. This makes species separation at geographic scales more demanding and suggests a

  1. Tracing early stages of species differentiation: Ecological, morphological and genetic divergence of Galápagos sea lion populations

    Directory of Open Access Journals (Sweden)

    Brunner Sylvia

    2008-05-01

    Full Text Available Abstract Background Oceans are high gene flow environments that are traditionally believed to hamper the build-up of genetic divergence. Despite this, divergence appears to occur occasionally at surprisingly small scales. The Galápagos archipelago provides an ideal opportunity to examine the evolutionary processes of local divergence in an isolated marine environment. Galápagos sea lions (Zalophus wollebaeki are top predators in this unique setting and have an essentially unlimited dispersal capacity across the entire species range. In theory, this should oppose any genetic differentiation. Results We find significant ecological, morphological and genetic divergence between the western colonies and colonies from the central region of the archipelago that are exposed to different ecological conditions. Stable isotope analyses indicate that western animals use different food sources than those from the central area. This is likely due to niche partitioning with the second Galápagos eared seal species, the Galápagos fur seal (Arctocephalus galapagoensis that exclusively dwells in the west. Stable isotope patterns correlate with significant differences in foraging-related skull morphology. Analyses of mitochondrial sequences as well as microsatellites reveal signs of initial genetic differentiation. Conclusion Our results suggest a key role of intra- as well as inter-specific niche segregation in the evolution of genetic structure among populations of a highly mobile species under conditions of free movement. Given the monophyletic arrival of the sea lions on the archipelago, our study challenges the view that geographical barriers are strictly needed for the build-up of genetic divergence. The study further raises the interesting prospect that in social, colonially breeding mammals additional forces, such as social structure or feeding traditions, might bear on the genetic partitioning of populations.

  2. Divergence and gene flow in the globally distributed blue-winged ducks

    Science.gov (United States)

    Nelson, Joel; Wilson, Robert E.; McCracken, Kevin G.; Cumming, Graeme; Joseph, Leo; Guay, Patrick-Jean; Peters, Jeffrey

    2017-01-01

    The ability to disperse over long distances can result in a high propensity for colonizing new geographic regions, including uninhabited continents, and lead to lineage diversification via allopatric speciation. However, high vagility can also result in gene flow between otherwise allopatric populations, and in some cases, parapatric or divergence-with-gene-flow models might be more applicable to widely distributed lineages. Here, we use five nuclear introns and the mitochondrial control region along with Bayesian models of isolation with migration to examine divergence, gene flow, and phylogenetic relationships within a cosmopolitan lineage comprising six species, the blue-winged ducks (genus Anas), which inhabit all continents except Antarctica. We found two primary sub-lineages, the globally-distributed shoveler group and the New World blue-winged/cinnamon teal group. The blue-winged/cinnamon sub-lineage is composed of sister taxa from North America and South America, and taxa with parapatric distributions are characterized by low to moderate levels of gene flow. In contrast, our data support strict allopatry for most comparisons within the shovelers. However, we found evidence of gene flow from the migratory, Holarctic northern shoveler (A. clypeata) and the more sedentary, African Cape shoveler (A. smithii) into the Australasian shoveler (A. rhynchotis), although we could not reject strict allopatry. Given the diverse mechanisms of speciation within this complex, the shovelers and blue-winged/cinnamon teals can serve as an effective model system for examining how the genome diverges under different evolutionary processes and how genetic variation is partitioned among highly dispersive taxa.

  3. Chemical variation in a dominant tree species: population divergence, selection and genetic stability across environments.

    Directory of Open Access Journals (Sweden)

    Julianne M O'Reilly-Wapstra

    Full Text Available Understanding among and within population genetic variation of ecologically important plant traits provides insight into the potential evolutionary processes affecting those traits. The strength and consistency of selection driving variability in traits would be affected by plasticity in differences among genotypes across environments (G×E. We investigated population divergence, selection and environmental plasticity of foliar plant secondary metabolites (PSMs in a dominant tree species, Eucalyptus globulus. Using two common garden trials we examined variation in PSMs at multiple genetic scales; among 12 populations covering the full geographic range of the species and among up to 60 families within populations. Significant genetic variation in the expression of many PSMs resides both among and within populations of E. globulus with moderate (e.g., sideroxylonal A h(2op = 0.24 to high (e.g., macrocarpal G h(2op = 0.48 narrow sense heritabilities and high coefficients of additive genetic variation estimated for some compounds. A comparison of Qst and Fst estimates suggest that variability in some of these traits may be due to selection. Importantly, there was no genetic by environment interaction in the expression of any of the quantitative chemical traits despite often significant site effects. These results provide evidence that natural selection has contributed to population divergence in PSMs in E. globulus, and identifies the formylated phloroglucinol compounds (particularly sideroxylonal and a dominant oil, 1,8-cineole, as candidates for traits whose genetic architecture has been shaped by divergent selection. Additionally, as the genetic differences in these PSMs that influence community phenotypes is stable across environments, the role of plant genotype in structuring communities is strengthened and these genotypic differences may be relatively stable under global environmental changes.

  4. Jensen divergence based on Fisher’s information

    International Nuclear Information System (INIS)

    Sánchez-Moreno, P; Zarzo, A; Dehesa, J S

    2012-01-01

    The measure of Jensen–Fisher divergence between probability distributions is introduced and its theoretical grounds set up. This quantity, in contrast to the remaining Jensen divergences, grasps the fluctuations of the probability distributions because it is controlled by the (local) Fisher information, which is a gradient functional of the distribution. So it is appropriate and informative when studying the similarity of distributions, mainly for those having oscillatory character. The new Jensen–Fisher divergence shares with the Jensen–Shannon divergence the following properties: non-negativity, additivity when applied to an arbitrary number of probability densities, symmetry under exchange of these densities, vanishing under certain conditions and definiteness even when these densities present non-common zeros. Moreover, the Jensen–Fisher divergence is shown to be expressed in terms of the relative Fisher information as the Jensen–Shannon divergence does in terms of the Kullback–Leibler or relative Shannon entropy. Finally, the Jensen–Shannon and Jensen–Fisher divergences are compared for the following three large, non-trivial and qualitatively different families of probability distributions: the sinusoidal, generalized gamma-like and Rakhmanov–Hermite distributions, which are closely related to the quantum-mechanical probability densities of numerous physical systems. (paper)

  5. Total Bregman Divergence and its Applications to Shape Retrieval.

    Science.gov (United States)

    Liu, Meizhu; Vemuri, Baba C; Amari, Shun-Ichi; Nielsen, Frank

    2010-01-01

    Shape database search is ubiquitous in the world of biometric systems, CAD systems etc. Shape data in these domains is experiencing an explosive growth and usually requires search of whole shape databases to retrieve the best matches with accuracy and efficiency for a variety of tasks. In this paper, we present a novel divergence measure between any two given points in [Formula: see text] or two distribution functions. This divergence measures the orthogonal distance between the tangent to the convex function (used in the definition of the divergence) at one of its input arguments and its second argument. This is in contrast to the ordinate distance taken in the usual definition of the Bregman class of divergences [4]. We use this orthogonal distance to redefine the Bregman class of divergences and develop a new theory for estimating the center of a set of vectors as well as probability distribution functions. The new class of divergences are dubbed the total Bregman divergence (TBD). We present the l 1 -norm based TBD center that is dubbed the t-center which is then used as a cluster center of a class of shapes The t-center is weighted mean and this weight is small for noise and outliers. We present a shape retrieval scheme using TBD and the t-center for representing the classes of shapes from the MPEG-7 database and compare the results with other state-of-the-art methods in literature.

  6. Genetic divergence and its implication in breeding of desired plant type in coriander -Coriandrum sativum L.-

    Directory of Open Access Journals (Sweden)

    Singh S.P.

    2005-01-01

    Full Text Available Seventy germplasm lines of coriander (Coriandrum sativum L. of diverse eco-geographical origin were undertaken in present investigation to determine the genetic divergence following multivariate and canonical analysis for seed yield and its 9 component traits. The 70 genotypes were grouped into 9 clusters depending upon the genetic architecture of genotypes and characters uniformity and confirmed by canonical analysis. Seventy percent of total genotypes (49/70 were grouped in 4 clusters (V, VI, VIII and IX, while apparent diversity was noticed for 30 percent genotypes (21/70 that diverged into 5 clusters (I, II, III, FV, and VII. The maximum inter cluster distance was between I and IV (96.20 followed by III and IV (91.13 and I and VII (87.15. The cluster VI was very unique having genotypes of high mean values for most of the component traits. The cluster VII had highest seeds/umbel (35.3 ± 2.24, and leaves/plant (12.93 ± 0.55, earliest flowering (65.05 ± 1.30 and moderately high mean values for other characters. Considering high mean and inter cluster distance breeding plan has been discussed to select desirable plant types.

  7. Deep genetic divergence between disjunct Refugia in the Arctic-Alpine King's Crown, Rhodiola integrifolia (Crassulaceae.

    Directory of Open Access Journals (Sweden)

    Eric G DeChaine

    Full Text Available Despite the strength of climatic variability at high latitudes and upper elevations, we still do not fully understand how plants in North America that are distributed between Arctic and alpine areas responded to the environmental changes of the Quaternary. To address this question, we set out to resolve the evolutionary history of the King's Crown, Rhodiola integrifolia using multi-locus population genetic and phylogenetic analyses in combination with ecological niche modeling. Our population genetic analyses of multiple anonymous nuclear loci revealed two major clades within R. integrifolia that diverged from each other ~ 700 kya: one occurring in Beringia to the north (including members of subspecies leedyi and part of subspecies integrifolia, and the other restricted to the Southern Rocky Mountain refugium in the south (including individuals of subspecies neomexicana and part of subspecies integrifolia. Ecological niche models corroborate our hypothesized locations of refugial areas inferred from our phylogeographic analyses and revealed some environmental differences between the regions inhabited by its two subclades. Our study underscores the role of geographic isolation in promoting genetic divergence and the evolution of endemic subspecies in R. integrifolia. Furthermore, our phylogenetic analyses of the plastid spacer region trnL-F demonstrate that among the native North American species, R. integrifolia and R. rhodantha are more closely related to one another than either is to R. rosea. An understanding of these historic processes lies at the heart of making informed management decisions regarding this and other Arctic-alpine species of concern in this increasingly threatened biome.

  8. The measure of success: geographic isolation promotes diversification in Pachydactylus geckos.

    Science.gov (United States)

    Heinicke, Matthew P; Jackman, Todd R; Bauer, Aaron M

    2017-01-11

    Geckos of the genus Pachydactylus and their close relatives comprise the most species-rich clade of lizards in sub-Saharan Africa. Many explanations have been offered to explain species richness patterns of clades. In the Pachydactylus group, one possible explanation is a history of diversification via geographic isolation. If geographic isolation has played a key role in facilitating diversification, then we expect species in more species-rich subclades to have smaller ranges than species in less diverse subclades. We also expect traits promoting geographic isolation to be correlated with small geographic ranges. In order to test these expectations, we performed phylogenetic analyses and tested for correlations among body size, habitat choice, range sizes, and diversification rates in the Pachydactylus group. Both body size and habitat use are inferred to have shifted multiple times across the phylogeny of the Pachydactylus group, with large size and generalist habitat use being ancestral for the group. Geographic range size is correlated with both of these traits. Small-bodied species have more restricted ranges than large-bodied species, and rock-dwelling species have more restricted ranges than either terrestrial or generalist species. Rock-dwelling and small body size are also associated with higher rates of diversification, and subclades retaining ancestral conditions for these traits are less species rich than subclades in which shifts to small body size and rocky habitat use have occurred. The phylogeny also illustrates inadequacies of the current taxonomy of the group. The results are consistent with a model in which lineages more likely to become geographically isolated diversify to a greater extent, although some patterns also resemble those expected of an adaptive radiation in which ecological divergence acts as a driver of speciation. Therefore, the Pachydactylus group may represent an intermediate between clades in which radiation is adaptive versus

  9. Interspecific genetic divergence in grey mullets from the Goa region

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.; Martins, M.; Naik, S.

    Genetic divergence and phylogenetic relationships among Mugil cephalus, Liza subviridis and Valamugil cunnesius were investigated by examining the electrophoretic patterns of ten enzymes and sarcoplasmic proteins. Among the 19 loci detected, eight...

  10. Role of mantle flow in Nubia-Somalia plate divergence

    Science.gov (United States)

    Stamps, D. S.; Iaffaldano, G.; Calais, E.

    2015-01-01

    Present-day continental extension along the East African Rift System (EARS) has often been attributed to diverging sublithospheric mantle flow associated with the African Superplume. This implies a degree of viscous coupling between mantle and lithosphere that remains poorly constrained. Recent advances in estimating present-day opening rates along the EARS from geodesy offer an opportunity to address this issue with geodynamic modeling of the mantle-lithosphere system. Here we use numerical models of the global mantle-plates coupled system to test the role of present-day mantle flow in Nubia-Somalia plate divergence across the EARS. The scenario yielding the best fit to geodetic observations is one where torques associated with gradients of gravitational potential energy stored in the African highlands are resisted by weak continental faults and mantle basal drag. These results suggest that shear tractions from diverging mantle flow play a minor role in present-day Nubia-Somalia divergence.

  11. Diverging diamond interchange performance evaluation (I-44 and Route 13)

    Science.gov (United States)

    2011-02-01

    Performance evaluation was conducted on the first diverging diamond interchange (DDI) or double : crossover interchange (DCD) constructed in the United States. This evaluation assessed traffic operations, safety and : public perceptions t...

  12. A divergence theorem for pseudo-Finsler spaces

    OpenAIRE

    Minguzzi, E.

    2015-01-01

    We study the divergence theorem on pseudo-Finsler spaces and obtain a completely Finslerian version for spaces having a vanishing mean Cartan torsion. This result helps to clarify the problem of energy-momentum conservation in Finsler gravity theories.

  13. Stora's fine notion of divergent amplitudes

    International Nuclear Information System (INIS)

    Várilly, Joseph C.; Gracia-Bondía, José M.

    2016-01-01

    Stora and coworkers refined the notion of divergent quantum amplitude, somewhat upsetting the standard power-counting recipe. This unexpectedly clears the way to new prototypes for free and interacting field theories of bosons of any mass and spin.

  14. Principal Curves for Statistical Divergences and an Application to Finance

    Directory of Open Access Journals (Sweden)

    Ana Flávia P. Rodrigues

    2018-05-01

    Full Text Available This paper proposes a method for the beta pricing model under the consideration of non-Gaussian returns by means of a generalization of the mean-variance model and the use of principal curves to define a divergence model for the optimization of the pricing model. We rely on the q-exponential model so consider the properties of the divergences which are used to describe the statistical model and fully characterize the behavior of the assets. We derive the minimum divergence portfolio, which generalizes the Markowitz’s (mean-divergence approach and relying on the information geometrical aspects of the distributions the Capital Asset Pricing Model (CAPM is then derived under the geometrical characterization of the distributions which model the data, all by the consideration of principal curves approach. We discuss the possibility of integration of our model into an adaptive procedure that can be used for the search of optimum points on finance applications.

  15. NATO Technology: From Gap to Divergence? (Defense Horizons, July 2004)

    National Research Council Canada - National Science Library

    Daniel, Donald

    2004-01-01

    .... Over several decades, great disparities in the funding of defense research and technology by NATO members has produced a widening technological gap that threatens to become a divergence a condition...

  16. Camouflage target detection via hyperspectral imaging plus information divergence measurement

    Science.gov (United States)

    Chen, Yuheng; Chen, Xinhua; Zhou, Jiankang; Ji, Yiqun; Shen, Weimin

    2016-01-01

    Target detection is one of most important applications in remote sensing. Nowadays accurate camouflage target distinction is often resorted to spectral imaging technique due to its high-resolution spectral/spatial information acquisition ability as well as plenty of data processing methods. In this paper, hyper-spectral imaging technique together with spectral information divergence measure method is used to solve camouflage target detection problem. A self-developed visual-band hyper-spectral imaging device is adopted to collect data cubes of certain experimental scene before spectral information divergences are worked out so as to discriminate target camouflage and anomaly. Full-band information divergences are measured to evaluate target detection effect visually and quantitatively. Information divergence measurement is proved to be a low-cost and effective tool for target detection task and can be further developed to other target detection applications beyond spectral imaging technique.

  17. Evolutionary History of a Desert Shrub Ephedra przewalskii (Ephedraceae): Allopatric Divergence and Range Shifts in Northwestern China.

    Science.gov (United States)

    Su, Zhi-Hao; Zhang, Ming-Li

    2016-01-01

    Based on two chloroplast DNA sequences, psbA-trnH and trnT-trnF, phylogeographical patterns of a desert shrub, Ephedra przewalskii, were examined across most of its geographic range in northwestern China. A total of sixteen haplotypes were detected. There was a common haplotype in each basin, that was haplotype A in Tarim Basin, haplotype G in Junggar Basin, and haplotype M in Qaidam Basin. Genetic variance mainly occurred among populations, geographic regions, and eleven geographic groups subdivided by SAMOVA analysis. E. przewalskii likely had a smaller and more fragmented geographic range during the Last Glacial Maximum, which was determined based on ecological niche modelling. Three groups of E. przewalskii populations were detected to have experience range expansion, and this was based on significant values of Fu's FS, Tajima's D, and unimodel mismatch distributions. The cold and dry climate during the glacial period of the Quaternary is postulated to have been a driver for significant genetic isolation and divergence among populations or groups in E. przewalskii, whereas the warmer and wetter climate during the interglacial period is speculated to have provided favourable conditions for range expansion of the species.

  18. Where the lake meets the sea: strong reproductive isolation is associated with adaptive divergence between lake resident and anadromous three-spined sticklebacks.

    Directory of Open Access Journals (Sweden)

    Mark Ravinet

    Full Text Available Contact zones between divergent forms of the same species are often characterised by high levels of phenotypic diversity over small geographic distances. What processes are involved in generating such high phenotypic diversity? One possibility is that introgression and recombination between divergent forms in contact zones results in greater phenotypic and genetic polymorphism. Alternatively, strong reproductive isolation between forms may maintain distinct phenotypes, preventing homogenisation by gene flow. Contact zones between divergent freshwater-resident and anadromous stickleback (Gasterosteus aculeatus L. forms are numerous and common throughout the species distribution, offering an opportunity to examine these contrasting hypotheses in greater detail. This study reports on an interesting new contact zone located in a tidally influenced lake catchment in western Ireland, characterised by high polymorphism for lateral plate phenotypes. Using neutral and QTL-linked microsatellite markers, we tested whether the high diversity observed in this contact zone arose as a result of introgression or reproductive isolation between divergent forms: we found strong support for the latter hypothesis. Three phenotypic and genetic clusters were identified, consistent with two divergent resident forms and a distinct anadromous completely plated population that migrates in and out of the system. Given the strong neutral differentiation detected between all three morphotypes (mean FST = 0.12, we hypothesised that divergent selection between forms maintains reproductive isolation. We found a correlation between neutral genetic and adaptive genetic differentiation that support this. While strong associations between QTL linked markers and phenotypes were also observed in this wild population, our results support the suggestion that such associations may be more complex in some Atlantic populations compared to those in the Pacific. These findings provide an

  19. Impact of urothelial carcinoma with divergent differentiation on tumor stage

    Directory of Open Access Journals (Sweden)

    S Chalise

    2016-03-01

    Full Text Available Background: Urinary bladder cancer is classified as urothelial or non-urothelial. Ninenty percent of bladder cancer are urothelial and has propensity for divergent differentiation. Squamous differentiation is associated with unfavourable prognostic features. The aim of this study is to determine the significance of urothelial carcinoma with divergent differentiation in relation to tumor stage and lymphovascular as well as perineural invasion in radical cystectomy and partial cystectomy specimen.Materials and methods: This prospective study was done among 51 patients who underwent radical cystectomy or partial cystectomy at Bhaktapur Cancer Hospital from 1st August 2013 to 31st December 2015. Received specimen was grossed following standard protocol and histopathological evaluation was done in relation to tumor type, depth of invasion, Lymphovascular and perineural invasion.Results: Pure urothelial carcinoma comprises 47.1% of cases. Among the divergent differentiation, urothelial carcinoma with squamous differentiation was the commonest one (39.2% followed by glandular differentiation (5.9%, sarcomatoid differentiation (3.9%, clear cell variant (2.0% and squamous along with sarcomatoid variant (2.0%. Statistical significant correlation was found between urothelial carcinoma with divergent differentiation and tumor stage (p<0.012. Statistically significant correlation was also found between urothelial carcinoma with divergent differentiation and lymphovascular invasion (p=0.012 as well as perineural invasion (p=0.037.Conclusion:  Most common divergent differentiation was squamous differentiation. Urothelial carcinoma with divergent differentiation was associated with higher stage and lymphovascular as well as perineural invasion. So it is mandatory to search for the divergent differentiation in urothelial carcinoma as this may be associated with unfavourable prognosis.

  20. The direct Flow parametric Proof of Gauss' Divergence Theorem revisited

    OpenAIRE

    Markvorsen, Steen

    2006-01-01

    The standard proof of the divergence theorem in undergraduate calculus courses covers the theorem for static domains between two graph surfaces. We show that within first year undergraduate curriculum, the flow proof of the dynamic version of the divergence theorem - which is usually considered only much later in more advanced math courses - is comprehensible with only a little extension of the first year curriculum. Moreover, it is more intuitive than the static proof. We support this intuit...

  1. Dimensional regularization and infrared divergences in quantum electrodynamics

    International Nuclear Information System (INIS)

    Marculescu, S.

    1979-01-01

    Dimensional continuation was devised as a powerful regularization method for ultraviolet divergences in quantum field theories. Recently it was clear, at least for quantum electrodynamics, that such a method could be employed for factorizing out infrared divergences from the on-shell S-matrix elements. This provides a renormalization scheme on the electron mass-shell without using a gauge violating ''photon mass''. (author)

  2. Diverging Trade Strategies in Latin America: An Analytical Framework

    OpenAIRE

    Aggarwal, Vinod K.; Espach, Ralph H.

    2003-01-01

    Although there is increasing divergence among the trade policies of various Latin American nations, overall the last twenty years have seen a dramatic shift away from protectionism towards liberalization. Focusing on case studies of four Latin American nations — Brazil, Mexico, Chile and Argentina — the authors use an analytical framework to explain the rationales behind divergent policies. The analytical approach used considers the combination of economic, political and strategic objectives ...

  3. Robust bounds on risk-sensitive functionals via Renyi divergence

    OpenAIRE

    Atar, Rami; Chowdhary, Kamaljit; Dupuis, Paul

    2013-01-01

    We extend the duality between exponential integrals and relative entropy to a variational formula for exponential integrals involving the Renyi divergence. This formula characterizes the dependence of risk-sensitive functionals and related quantities determined by tail behavior to perturbations in the underlying distributions, in terms of the Renyi divergence. The characterization gives rise to upper and lower bounds that are meaningful for all values of a large deviation scaling parameter, a...

  4. Genetic structure, divergence and admixture of Han Chinese, Japanese and Korean populations.

    Science.gov (United States)

    Wang, Yuchen; Lu, Dongsheng; Chung, Yeun-Jun; Xu, Shuhua

    2018-01-01

    Han Chinese, Japanese and Korean, the three major ethnic groups of East Asia, share many similarities in appearance, language and culture etc., but their genetic relationships, divergence times and subsequent genetic exchanges have not been well studied. We conducted a genome-wide study and evaluated the population structure of 182 Han Chinese, 90 Japanese and 100 Korean individuals, together with the data of 630 individuals representing 8 populations wordwide. Our analyses revealed that Han Chinese, Japanese and Korean populations have distinct genetic makeup and can be well distinguished based on either the genome wide data or a panel of ancestry informative markers (AIMs). Their genetic structure corresponds well to their geographical distributions, indicating geographical isolation played a critical role in driving population differentiation in East Asia. The most recent common ancestor of the three populations was dated back to 3000 ~ 3600 years ago. Our analyses also revealed substantial admixture within the three populations which occurred subsequent to initial splits, and distinct gene introgression from surrounding populations, of which northern ancestral component is dominant. These estimations and findings facilitate to understanding population history and mechanism of human genetic diversity in East Asia, and have implications for both evolutionary and medical studies.

  5. Geographic Education--Where Have We Failed?

    Science.gov (United States)

    Gritzner, Charles F.

    1981-01-01

    Discusses geography's rather low status and relatively poor public image in the United States and some of the consequences. Among the world's educated industrial nations, the United States ranks among the least literate in a geographical sense. (RM)

  6. Medicare Geographic Variation - Public Use File

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medicare Geographic Variation Public Use File provides the ability to view demographic, utilization and quality indicators at the state level (including...

  7. Geographic information system planning and monitoring best ...

    African Journals Online (AJOL)

    Poor urbanization policies, inefficient planning and monitoring technologies are evident. The consequences include some of the worst types of environmental hazards. Best urbanization practices require integrated planning approaches that result in environmental conservation. Geographic Information systems (GIS) provide ...

  8. GNIS: Geographic Names Information Systems - All features

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The Geographic Names Information System (GNIS) actively seeks data from and partnerships with Government agencies at all levels and other interested organizations....

  9. Geographic Variation in Medicare Spending Dashboard

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Geographic Variation Dashboards present Medicare fee-for-service per-capita spending at the state and county level in an interactive format. We calculated the...

  10. Geographic isolation and elevational gradients promote diversification in an endemic shrew on Sulawesi.

    Science.gov (United States)

    Eldridge, Ryan A; Achmadi, Anang S; Giarla, Thomas C; Rowe, Kevin C; Esselstyn, Jacob A

    2018-01-01

    Phylogeographic research on endemic primates and amphibians inhabiting the Indonesian island of Sulawesi revealed the existence of seven areas of endemism (AoEs). Here, we use phylogenetic and population genetic analyses of one mitochondrial gene and 15 nuclear loci to assess geographic patterns of genetic partitioning in a shrew (Crocidura elongata) that is endemic to Sulawesi, but occurs across the island. We uncover substantial genetic diversity in this species both between and within AoEs, but we also identify close relationships between populations residing in different AoEs. One of the earliest divergences within C. elongata distinguishes a high-elevation clade from low-elevation clades. In addition, on one mountain, we observe three distinct genetic groups from low, middle, and high elevations, suggesting divergence along a single elevational gradient. In general, our results show that C. elongata, like several other Sulawesi endemic taxa, harbors extensive genetic diversity. This diversity is structured in part by known AoE boundaries, but also by elevational gradients and geographic isolation within AoEs. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Genetic diversity and geographical dispersal in grapevine clones revealed by microsatellite markers.

    Science.gov (United States)

    Moncada, Ximena; Pelsy, Frédérique; Merdinoglu, Didier; Hinrichsen, Patricio

    2006-11-01

    Intravarietal genetic diversification associated with geographical dispersal of a vegetatively propagated species was studied using grapevine Vitis vinifera L. 'Cabernet Sauvignon' as a model. Fifty-nine clonal samples obtained from 7 countries (France, Chile, Spain, Australia, Hungary, USA, and Italy) were analyzed using 84 microsatellite markers. Eighteen polymorphic microsatellite loci (21.4%) were detected, finding 22 different genotypes in the population analyzed with a genetic similarity of over 97%. The presence of chimeric clones was evidenced at locus VMC5g7 by means of a segregation analysis of descendants by self-pollination of a triallelic Chilean clone and by somatic embryogenesis analysis, showing a mutation in L2 cell layer. Only 2 clones (obtained from France and Australia) presented the ancestral genotype, and the most divergent genotype was exhibited by another French clone, which had accumulated 5 somatic mutations. The 2 largest populations considered (from France and Chile) showed a clear divergency in the polymorphisms detected. These antecedents enabled the tracing of geographical dispersal with a phylogenetic hypothesis supporting France as the center of origin of diversification of Cabernet Sauvignon. The results obtained could help to explain diversification processes in other grapevine cultivars. The possibility that this kind of genetic variability occurs in other vegetatively propagated species is discussed, focusing on possible fingerprinting applications.

  12. Neural Mechanisms of Episodic Retrieval Support Divergent Creative Thinking.

    Science.gov (United States)

    Madore, Kevin P; Thakral, Preston P; Beaty, Roger E; Addis, Donna Rose; Schacter, Daniel L

    2017-11-17

    Prior research has indicated that brain regions and networks that support semantic memory, top-down and bottom-up attention, and cognitive control are all involved in divergent creative thinking. Kernels of evidence suggest that neural processes supporting episodic memory-the retrieval of particular elements of prior experiences-may also be involved in divergent thinking, but such processes have typically been characterized as not very relevant for, or even a hindrance to, creative output. In the present study, we combine functional magnetic resonance imaging with an experimental manipulation to test formally, for the first time, episodic memory's involvement in divergent thinking. Following a manipulation that facilitates detailed episodic retrieval, we observed greater neural activity in the hippocampus and stronger connectivity between a core brain network linked to episodic processing and a frontoparietal brain network linked to cognitive control during divergent thinking relative to an object association control task that requires little divergent thinking. Stronger coupling following the retrieval manipulation extended to a subsequent resting-state scan. Neural effects of the episodic manipulation were consistent with behavioral effects of enhanced idea production on divergent thinking but not object association. The results indicate that conceptual frameworks should accommodate the idea that episodic retrieval can function as a component process of creative idea generation, and highlight how the brain flexibly utilizes the retrieval of episodic details for tasks beyond simple remembering. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  13. Riverscape genetics identifies replicated ecological divergence across an Amazonian ecotone.

    Science.gov (United States)

    Cooke, Georgina M; Landguth, Erin L; Beheregaray, Luciano B

    2014-07-01

    Ecological speciation involves the evolution of reproductive isolation and niche divergence in the absence of a physical barrier to gene flow. The process is one of the most controversial topics of the speciation debate, particularly in tropical regions. Here, we investigate ecologically based divergence across an Amazonian ecotone in the electric fish, Steatogenys elegans. We combine phylogenetics, genome scans, and population genetics with a recently developed individual-based evolutionary landscape genetics approach that incorporates selection. This framework is used to assess the relative contributions of geography and divergent natural selection between environments as biodiversity drivers. We report on two closely related and sympatric lineages that exemplify how divergent selection across a major Amazonian aquatic ecotone (i.e., between rivers with markedly different hydrochemical properties) may result in replicated ecologically mediated speciation. The results link selection across an ecological gradient with reproductive isolation and we propose that assortative mating based on water color may be driving the divergence. Divergence resulting from ecologically driven selection highlights the importance of considering environmental heterogeneity in studies of speciation in tropical regions. Furthermore, we show that framing ecological speciation in a spatially explicit evolutionary landscape genetics framework provides an important first step in exploring a wide range of the potential effects of spatial dependence in natural selection. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  14. Geographical variation in cardiovascular incidence: results from the British Women's Heart and Health Study

    Directory of Open Access Journals (Sweden)

    Ebrahim Shah

    2010-11-01

    Full Text Available Abstract Background Prevalence of cardiovascular disease (CVD in women shows regional variations not explained by common risk factors. Analysis of CVD incidence will provide insight into whether there is further divergence between regions with increasing age. Methods Seven-year follow-up data on 2685 women aged 59-80 (mean 69 at baseline from 23 towns in the UK were available from the British Women's Heart and Health Study. Time to fatal or non-fatal CVD was analyzed using Cox regression with adjustment for risk factors, using multiple imputation for missing values. Results Compared to South England, CVD incidence is similar in North England (HR 1.05 (95% CI 0.84, 1.31 and Scotland (0.93 (0.68, 1.27, but lower in Midlands/Wales (0.85 (0.64, 1.12. Event severity influenced regional variation, with South England showing lower fatal incident CVD than other regions, but higher non-fatal incident CVD. Kaplan-Meier plots suggested that regional divergence in CVD occurred before baseline (before mean baseline age of 69. Conclusions In women, regional differences in CVD early in adult life do not further diverge in later life. This may be due to regional differences in early detection, survivorship of women entering the study, or event severity. Targeting health care resources for CVD by geographic variation may not be appropriate for older age-groups.

  15. Phylogeography and allopatric divergence of cypress species (Cupressus L.) in the Qinghai-Tibetan Plateau and adjacent regions.

    Science.gov (United States)

    Xu, Tingting; Abbott, Richard J; Milne, Richard I; Mao, Kangshan; Du, Fang K; Wu, Guili; Ciren, Zhaxi; Miehe, Georg; Liu, Jianquan

    2010-06-22

    Although allopatric speciation is viewed as the most common way in which species originate, allopatric divergence among a group of closely related species has rarely been examined at the population level through phylogeographic analysis. Here we report such a case study on eight putative cypress (Cupressus) species, which each have a mainly allopatric distribution in the Qinghai-Tibetan Plateau (QTP) and adjacent regions. The analysis involved sequencing three plastid DNA fragments (trnD-trnT, trnS-trnG and trnL-trnF) in 371 individuals sampled from populations at 66 localities. Both phylogenetic and network analyses showed that most DNA haplotypes recovered or haplotype-clustered lineages resolved were largely species-specific. Across all species, significant phylogeographic structure (N(ST) > G(ST), P allopatric divergence in Cupressus by restricting gene flow and fixing local, species-specific haplotypes in geographically isolated populations. The low levels of intraspecific diversity present in most species might stem from population bottlenecks brought about by recurrent periods of unfavorable climate and more recently by the negative impacts of human activities on species' distributions. Our findings shed new light on the importance of geographical isolation caused by the uplift of the QTP on the development of high plant species diversity in the QTP biodiversity hotspot.

  16. The influence of life-history strategy on genetic differentiation and lineage divergence in darters (Percidae: Etheostomatinae).

    Science.gov (United States)

    Fluker, Brook L; Kuhajda, Bernard R; Harris, Phillip M

    2014-11-01

    Recent studies determined that darters with specialized breeding strategies can exhibit deep lineage divergence over fine geographic scales without apparent physical barriers to gene flow. However, the extent to which intrinsic characteristics interact with extrinsic factors to influence population divergence and lineage diversification in darters is not well understood. This study employed comparative phylogeographic and population genetic methods to investigate the influence of life history on gene flow, dispersal ability, and lineage divergence in two sympatric sister darters with differing breeding strategies. Our results revealed highly disparate phylogeographic histories, patterns of genetic structure, and dispersal abilities between the two species suggesting that life history may contribute to lineage diversification in darters, especially by limiting dispersal among large river courses. Both species also showed striking differences in demographic history, indicating that extrinsic factors differentially affected each species during the Pleistocene. Collectively, our results indicate that intrinsic and extrinsic factors have influenced levels of gene flow among populations within both species examined. However, we suggest that life-history strategy may play a more important role in lineage diversification in darters than previously appreciated, a finding that has potentially important implications for understanding diversification of the rich North American freshwater fish fauna. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  17. Genetic isolation and morphological divergence mediated by high-energy rapids in two cichlid genera from the lower Congo rapids

    Directory of Open Access Journals (Sweden)

    Stiassny Melanie LJ

    2010-05-01

    Full Text Available Abstract Background It is hypothesized that one of the mechanisms promoting diversification in cichlid fishes in the African Great Lakes has been the well-documented pattern of philopatry along shoreline habitats leading to high levels of genetic isolation among populations. However lake habitats are not the only centers of cichlid biodiversity - certain African rivers also contain large numbers of narrowly endemic species. Patterns of isolation and divergence in these systems have tended to be overlooked and are not well understood. Results We examined genetic and morphological divergence among populations of two narrowly endemic cichlid species, Teleogramma depressum and Lamprologus tigripictilis, from a 100 km stretch of the lower Congo River using both nDNA microsatellites and mtDNA markers along with coordinate-based morphological techniques. In L. tigripictilis, the strongest genetic break was concordant with measurable phenotypic divergence but no morphological disjunction was detected for T. depressum despite significant differentiation at mtDNA and nDNA microsatellite markers. Conclusions The genetic markers revealed patterns of philopatry and estimates of genetic isolation that are among the highest reported for any African cichlid species over a comparable geographic scale. We hypothesize that the high levels of philopatry observed are generated and maintained by the extreme hydrology of the lower Congo River.

  18. A Δ11 desaturase gene genealogy reveals two divergent allelic classes within the European corn borer (Ostrinia nubilalis

    Directory of Open Access Journals (Sweden)

    Harrison Richard G

    2010-04-01

    Full Text Available Abstract Background Moth pheromone mating systems have been characterized at the molecular level, allowing evolutionary biologists to study how changes in protein sequence or gene expression affect pheromone phenotype, patterns of mating, and ultimately, the formation of barriers to gene exchange. Recent studies of Ostrinia pheromones have focused on the diversity of sex pheromone desaturases and their role in the specificity of pheromone production. Here we produce a Δ11 desaturase genealogy within Ostrinia nubilalis. We ask what has been the history of this gene, and whether this history suggests that changes in Δ11 desaturase have been involved in the divergence of the E and Z O. nubilalis pheromone strains. Results The Δ11 desaturase gene genealogy does not differentiate O. nubilalis pheromone strains. However, we find two distinct clades, separated by 2.9% sequence divergence, that do not sort with pheromone strain, geographic origin, or emergence time. We demonstrate that these clades do not represent gene duplicates, but rather allelic variation at a single gene locus. Conclusions Analyses of patterns of variation at the Δ11 desaturase gene in ECB suggest that this enzyme does not contribute to reproductive isolation between pheromone strains (E and Z. However, our genealogy reveals two deeply divergent allelic classes. Standing variation at loci that contribute to mate choice phenotypes may permit novel pheromone mating systems to arise in the presence of strong stabilizing selection.

  19. Single nucleotide polymorphisms unravel hierarchical divergence and signatures of selection among Alaskan sockeye salmon (Oncorhynchus nerka populations

    Directory of Open Access Journals (Sweden)

    Habicht Christopher

    2011-02-01

    Full Text Available Abstract Background Disentangling the roles of geography and ecology driving population divergence and distinguishing adaptive from neutral evolution at the molecular level have been common goals among evolutionary and conservation biologists. Using single nucleotide polymorphism (SNP multilocus genotypes for 31 sockeye salmon (Oncorhynchus nerka populations from the Kvichak River, Alaska, we assessed the relative roles of geography (discrete boundaries or continuous distance and ecology (spawning habitat and timing driving genetic divergence in this species at varying spatial scales within the drainage. We also evaluated two outlier detection methods to characterize candidate SNPs responding to environmental selection, emphasizing which mechanism(s may maintain the genetic variation of outlier loci. Results For the entire drainage, Mantel tests suggested a greater role of geographic distance on population divergence than differences in spawn timing when each variable was correlated with pairwise genetic distances. Clustering and hierarchical analyses of molecular variance indicated that the largest genetic differentiation occurred between populations from distinct lakes or subdrainages. Within one population-rich lake, however, Mantel tests suggested a greater role of spawn timing than geographic distance on population divergence when each variable was correlated with pairwise genetic distances. Variable spawn timing among populations was linked to specific spawning habitats as revealed by principal coordinate analyses. We additionally identified two outlier SNPs located in the major histocompatibility complex (MHC class II that appeared robust to violations of demographic assumptions from an initial pool of eight candidates for selection. Conclusions First, our results suggest that geography and ecology have influenced genetic divergence between Alaskan sockeye salmon populations in a hierarchical manner depending on the spatial scale. Second

  20. Geographic Names Information System (GNIS) for Lousiana, Geographic NAD83, USGS (2007) [GNIS_LA_USGS_2007

    Data.gov (United States)

    Louisiana Geographic Information Center — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  1. DAST in Flight Showing Diverging Wingtip Oscillations

    Science.gov (United States)

    1980-01-01

    normal stiffness. This was done because stiffness requires structural weight but ensures freedom from flutter-an uncontrolled, divergent oscillation of the structure, driven by aerodynamic forces and resulting in structural failure. The program used refined theoretical tools to predict at what speed flutter would occur. It then designed a high-response control system to counteract the motion and permit a much lighter wing structure. The wing had, in effect, 'electronic stiffness.' Flight research with this concept was extremely hazardous because an error in either the flutter prediction or control system implementation would result in wing structural failure and the loss of the vehicle. Because of this, flight demonstration of a sub-scale vehicle made sense from the standpoint of both safety and cost. The program anticipated structural failure during the course of the flight research. The Firebee II was a supersonic drone selected as the DAST testbed because its wing could be easily replaced, it used only tail-mounted control surfaces, and it was available as surplus from the U. S. Air Force. It was capable of 5-g turns (that is, turns producing acceleration equal to 5 times that of gravity). Langley outfitted a drone with an aeroelastic, supercritical research wing suitable for a Mach 0.98 cruise transport with a predicted flutter speed of Mach 0.95 at an altitude of 25,000 feet. Dryden and Langley, in conjunction with Boeing, designed and fabricated a digital flutter suppression system (FSS). Dryden developed an RPRV (remotely piloted research vehicle) flight control system; integrated the wing, FSS, and vehicle systems; and conducted the flight program. In addition to a digital flight control system and aeroelastic wings, each DAST drone had research equipment mounted in its nose and a mid-air retrieval system in its tail. The drones were originally launched from the NASA B-52 bomber and later from a DC-130. The DAST vehicle's flight was monitored from the sky by an F

  2. Comparison of immunization strategies in geographical networks

    Energy Technology Data Exchange (ETDEWEB)

    Wang Bing; Aihara, Kazuyuki [Institute of Industrial Science, The University of Tokyo, Tokyo (Japan)] [ERATO Aihara Complexity Modelling Project, JST, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505 (Japan); Kim, Beom Jun, E-mail: beomjun@skku.ed [BK21 Physics Research Division and Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)] [Department of Computational Biology, School of Computer Science and Communication, Royal Institute of Technology, 100 44 Stockholm (Sweden)

    2009-10-12

    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.

  3. Personality Homophily and Geographic Distance in Facebook.

    Science.gov (United States)

    Noë, Nyala; Whitaker, Roger M; Allen, Stuart M

    2018-05-24

    Personality homophily remains an understudied aspect of social networks, with the traditional focus concerning sociodemographic variables as the basis for assortativity, rather than psychological dispositions. We consider the effect of personality homophily on one of the biggest constraints to human social networks: geographic distance. We use the Big five model of personality to make predictions for each of the five facets: Openness to experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism. Using a network of 313,669 Facebook users, we investigate the difference in geographic distance between homophilous pairs, in which both users scored similarly on a particular facet, and mixed pairs. In accordance with our hypotheses, we find that pairs of open and conscientious users are geographically further apart than mixed pairs. Pairs of extraverts, on the other hand, tend to be geographically closer together. We find mixed results for the Neuroticism facet, and no significant effects for the Agreeableness facet. The results are discussed in the context of personality homophily and the impact of geographic distance on social connections.

  4. Comparison of immunization strategies in geographical networks

    International Nuclear Information System (INIS)

    Wang Bing; Aihara, Kazuyuki; Kim, Beom Jun

    2009-01-01

    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.

  5. Speciation on oceanic islands: rapid adaptive divergence vs. cryptic speciation in a Guadalupe Island songbird (Aves: Junco.

    Directory of Open Access Journals (Sweden)

    Pau Aleixandre

    Full Text Available The evolutionary divergence of island populations, and in particular the tempo and relative importance of neutral and selective factors, is of central interest to the study of speciation. The rate of phenotypic evolution upon island colonization can vary greatly among taxa, and cases of convergent evolution can further confound the inference of correct evolutionary histories. Given the potential lability of phenotypic characters, molecular dating of insular lineages analyzed in a phylogenetic framework provides a critical tool to test hypotheses of phenotypic divergence since colonization. The Guadalupe junco is the only insular form of the polymorphic dark-eyed junco (Junco hyemalis, and shares eye and plumage color with continental morphs, yet presents an enlarged bill and reduced body size. Here we use variation in mtDNA sequence, morphological traits and song variables to test whether the Guadalupe junco evolved rapidly following a recent colonization by a mainland form of the dark-eyed junco, or instead represents a well-differentiated "cryptic" lineage adapted to the insular environment through long-term isolation, with plumage coloration a result of evolutionary convergence. We found high mtDNA divergence of the island lineage with respect to both continental J. hyemalis and J. phaeonotus, representing a history of isolation of about 600,000 years. The island lineage was also significantly differentiated in morphological and male song variables. Moreover, and contrary to predictions regarding diversity loss on small oceanic islands, we document relatively high levels of both haplotypic and song-unit diversity on Guadalupe Island despite long-term isolation in a very small geographic area. In contrast to prevailing taxonomy, the Guadalupe junco is an old, well-differentiated evolutionary lineage, whose similarity to mainland juncos in plumage and eye color is due to evolutionary convergence. Our findings confirm the role of remote islands

  6. Speciation on oceanic islands: rapid adaptive divergence vs. cryptic speciation in a Guadalupe Island songbird (Aves: Junco).

    Science.gov (United States)

    Aleixandre, Pau; Hernández Montoya, Julio; Milá, Borja

    2013-01-01

    The evolutionary divergence of island populations, and in particular the tempo and relative importance of neutral and selective factors, is of central interest to the study of speciation. The rate of phenotypic evolution upon island colonization can vary greatly among taxa, and cases of convergent evolution can further confound the inference of correct evolutionary histories. Given the potential lability of phenotypic characters, molecular dating of insular lineages analyzed in a phylogenetic framework provides a critical tool to test hypotheses of phenotypic divergence since colonization. The Guadalupe junco is the only insular form of the polymorphic dark-eyed junco (Junco hyemalis), and shares eye and plumage color with continental morphs, yet presents an enlarged bill and reduced body size. Here we use variation in mtDNA sequence, morphological traits and song variables to test whether the Guadalupe junco evolved rapidly following a recent colonization by a mainland form of the dark-eyed junco, or instead represents a well-differentiated "cryptic" lineage adapted to the insular environment through long-term isolation, with plumage coloration a result of evolutionary convergence. We found high mtDNA divergence of the island lineage with respect to both continental J. hyemalis and J. phaeonotus, representing a history of isolation of about 600,000 years. The island lineage was also significantly differentiated in morphological and male song variables. Moreover, and contrary to predictions regarding diversity loss on small oceanic islands, we document relatively high levels of both haplotypic and song-unit diversity on Guadalupe Island despite long-term isolation in a very small geographic area. In contrast to prevailing taxonomy, the Guadalupe junco is an old, well-differentiated evolutionary lineage, whose similarity to mainland juncos in plumage and eye color is due to evolutionary convergence. Our findings confirm the role of remote islands in driving

  7. Rotational and divergent kinetic energy in the mesoscale model ALADIN

    Directory of Open Access Journals (Sweden)

    V. Blažica

    2013-03-01

    Full Text Available Kinetic energy spectra from the mesoscale numerical weather prediction (NWP model ALADIN with horizontal resolution 4.4 km are split into divergent and rotational components which are then compared at horizontal scales below 300 km and various vertical levels. It is shown that about 50% of kinetic energy in the free troposphere in ALADIN is divergent energy. The percentage increases towards 70% near the surface and in the upper troposphere towards 100 hPa. The maximal percentage of divergent energy is found at stratospheric levels around 100 hPa and at scales below 100 km which are not represented by the global models. At all levels, the divergent energy spectra are characterised by shallower slopes than the rotational energy spectra, and the difference increases as horizontal scales become larger. A very similar vertical distribution of divergent energy is obtained by using the standard ALADIN approach for the computation of spectra based on the extension zone and by applying detrending approach commonly used in mesoscale NWP community.

  8. Sufficient Statistics for Divergence and the Probability of Misclassification

    Science.gov (United States)

    Quirein, J.

    1972-01-01

    One particular aspect is considered of the feature selection problem which results from the transformation x=Bz, where B is a k by n matrix of rank k and k is or = to n. It is shown that in general, such a transformation results in a loss of information. In terms of the divergence, this is equivalent to the fact that the average divergence computed using the variable x is less than or equal to the average divergence computed using the variable z. A loss of information in terms of the probability of misclassification is shown to be equivalent to the fact that the probability of misclassification computed using variable x is greater than or equal to the probability of misclassification computed using variable z. First, the necessary facts relating k-dimensional and n-dimensional integrals are derived. Then the mentioned results about the divergence and probability of misclassification are derived. Finally it is shown that if no information is lost (in x = Bz) as measured by the divergence, then no information is lost as measured by the probability of misclassification.

  9. Concrete ensemble Kalman filters with rigorous catastrophic filter divergence.

    Science.gov (United States)

    Kelly, David; Majda, Andrew J; Tong, Xin T

    2015-08-25

    The ensemble Kalman filter and ensemble square root filters are data assimilation methods used to combine high-dimensional, nonlinear dynamical models with observed data. Ensemble methods are indispensable tools in science and engineering and have enjoyed great success in geophysical sciences, because they allow for computationally cheap low-ensemble-state approximation for extremely high-dimensional turbulent forecast models. From a theoretical perspective, the dynamical properties of these methods are poorly understood. One of the central mysteries is the numerical phenomenon known as catastrophic filter divergence, whereby ensemble-state estimates explode to machine infinity, despite the true state remaining in a bounded region. In this article we provide a breakthrough insight into the phenomenon, by introducing a simple and natural forecast model that transparently exhibits catastrophic filter divergence under all ensemble methods and a large set of initializations. For this model, catastrophic filter divergence is not an artifact of numerical instability, but rather a true dynamical property of the filter. The divergence is not only validated numerically but also proven rigorously. The model cleanly illustrates mechanisms that give rise to catastrophic divergence and confirms intuitive accounts of the phenomena given in past literature.

  10. Sandwiched Rényi divergence satisfies data processing inequality

    International Nuclear Information System (INIS)

    Beigi, Salman

    2013-01-01

    Sandwiched (quantum) α-Rényi divergence has been recently defined in the independent works of Wilde et al. [“Strong converse for the classical capacity of entanglement-breaking channels,” preprint http://arxiv.org/abs/arXiv:1306.1586 (2013)] and Müller-Lennert et al. [“On quantum Rényi entropies: a new definition, some properties and several conjectures,” preprint http://arxiv.org/abs/arXiv:1306.3142v1 (2013)]. This new quantum divergence has already found applications in quantum information theory. Here we further investigate properties of this new quantum divergence. In particular, we show that sandwiched α-Rényi divergence satisfies the data processing inequality for all values of α > 1. Moreover we prove that α-Holevo information, a variant of Holevo information defined in terms of sandwiched α-Rényi divergence, is super-additive. Our results are based on Hölder's inequality, the Riesz-Thorin theorem and ideas from the theory of complex interpolation. We also employ Sion's minimax theorem

  11. Ayahuasca enhances creative divergent thinking while decreasing conventional convergent thinking.

    Science.gov (United States)

    Kuypers, K P C; Riba, J; de la Fuente Revenga, M; Barker, S; Theunissen, E L; Ramaekers, J G

    2016-09-01

    Ayahuasca is a South American psychotropic plant tea traditionally used in Amazonian shamanism. The tea contains the psychedelic 5-HT2A receptor agonist N,N-dimethyltryptamine (DMT), plus β-carboline alkaloids with monoamine oxidase-inhibiting properties. Increasing evidence from anecdotal reports and open-label studies indicates that ayahuasca may have therapeutic effects in treatment of substance use disorders and depression. A recent study on the psychological effects of ayahuasca found that the tea reduces judgmental processing and inner reactivity, classic goals of mindfulness psychotherapy. Another psychological facet that could potentially be targeted by ayahuasca is creative divergent thinking. This mode of thinking can enhance and strengthen psychological flexibility by allowing individuals to generate new and effective cognitive, emotional, and behavioral strategies. The present study aimed to assess the potential effects of ayahuasca on creative thinking. We visited two spiritual ayahuasca workshops and invited participants to conduct creativity tests before and during the acute effects of ayahuasca. In total, 26 participants consented. Creativity tests included the "pattern/line meanings test" (PLMT) and the "picture concept test" (PCT), both assessing divergent thinking and the latter also assessing convergent thinking. While no significant effects were found for the PLMT, ayahuasca intake significantly modified divergent and convergent thinking as measured by the PCT. While convergent thinking decreased after intake, divergent thinking increased. The present data indicate that ayahuasca enhances creative divergent thinking. They suggest that ayahuasca increases psychological flexibility, which may facilitate psychotherapeutic interventions and support clinical trial initiatives.

  12. Louisiana State Soil Geographic, General Soil Map, Geographic NAD83, NWRC (1998) [statsgo_soils_NWRC_1998

    Data.gov (United States)

    Louisiana Geographic Information Center — This data set contains vector line map information. The vector data contain selected base categories of geographic features, and characteristics of these features,...

  13. Thematic cartography as a geographical application

    Directory of Open Access Journals (Sweden)

    Drago Perko

    2002-12-01

    Full Text Available A thematic map may be a geographical application (tool in itself or the basis for some other geographical work. The development of Slovene thematic cartography accelerated considerably following the independence of the country in 1991. From the viewpoint of content and technology, its greatest achievements are the Geographical Atlas of Slovenia and the National Atlas of Slovenia, which are outstanding achievements at the international level and of great significance for the promotion of Slovenia and Slovene geography and cartography. However, this rapid development has been accompanied by numerous problems, for example, the ignoring of various Slovene and international conventions for the preparation of maps including United Nations resolutions, Slovene and international (SIST ISO, and copyright laws.

  14. Training for Internationalization through Domestic Geographical Dispersion

    DEFF Research Database (Denmark)

    Santangelo, Grazia D.; Stucchi, Tamara

    Traditionally created to deal with the unfriendly domestic environment, business groups (BGs) are increasingly internationalizing. However, how BGs can reconcile their strictly domestic orientation with an international dimension still remains an open question. Drawing on arguments from...... organizational learning, we seek to solve this puzzle in relation to the internationalization of Indian BGs. In particular, we argue that in heterogeneous domestic emerging markets BG’s geographical dispersion across sub-national states provides training for internationalization. To internationalize successfully......, BGs need to develop the capability of managing geographically dispersed units in institutional heterogeneous contexts. Domestic geographical dispersion would indeed help the BG dealing with different regulations, customers and infrastructures. However, there is less scope for such training as BGs...

  15. Connecting Amazonian, Cerrado, and Atlantic Forest histories: Paraphyly, old divergences, and modern population dynamics in tyrant-manakins (Neopelma/Tyranneutes, Aves: Pipridae).

    Science.gov (United States)

    Capurucho, João Marcos Guimarães; Ashley, Mary V; Ribas, Camila C; Bates, John M

    2018-06-11

    Several biogeographic hypotheses have been proposed to explain connections between Amazonian and Atlantic forest biotas. These hypotheses are related to the timing of the connections and their geographic patterns. We performed a phylogeographic investigation of Tyrant-manakins (Aves: Pipridae, Neopelma/Tyranneutes) which include species inhabiting the Amazon and Atlantic forests, as well as gallery forests of the Cerrado. Using DNA sequence data, we determined phylogenetic relationships, temporal and geographic patterns of diversification, and recent intraspecific population genetic patterns, relative to the history of these biomes. We found Neopelma to be a paraphyletic genus, as N. chrysolophum is sister to Neopelma + Tyranneutes, with an estimated divergence of approximately 18 Myrs BP, within the oldest estimated divergence times of other Amazonian and Atlantic forest avian taxa. Subsequent divergences in the group occurred from Mid Miocene to Early Pliocene and involved mainly the Amazonian species, with an expansion into and subsequent speciation in the Cerrado gallery forests by N. pallescens. We found additional structure within N. chrysocephalum and N. sulphureiventer. Analysis of recent population dynamics in N. chrysocephalum, N. sulphureiventer, and N. pallescens revealed recent demographic fluctuations and restrictions to gene flow related to environmental changes since the last glacial cycle. No genetic structure was detected across the Amazon River in N. pallescens. The tyrant-manakins represent an old historical connection between the Amazon and Atlantic Forest. Copyright © 2018. Published by Elsevier Inc.

  16. Computational Investigations in Rectangular Convergent and Divergent Ribbed Channels

    Science.gov (United States)

    Sivakumar, Karthikeyan; Kulasekharan, N.; Natarajan, E.

    2018-05-01

    Computational investigations on the rib turbulated flow inside a convergent and divergent rectangular channel with square ribs of different rib heights and different Reynolds numbers (Re=20,000, 40,000 and 60,000). The ribs were arranged in a staggered fashion between the upper and lower surfaces of the test section. Computational investigations are carried out using computational fluid dynamic software ANSYS Fluent 14.0. Suitable solver settings like turbulence models were identified from the literature and the boundary conditions for the simulations on a solution of independent grid. Computations were carried out for both convergent and divergent channels with 0 (smooth duct), 1.5, 3, 6, 9 and 12 mm rib heights, to identify the ribbed channel with optimal performance, assessed using a thermo hydraulic performance parameter. The convergent and divergent rectangular channels show higher Nu values than the standard correlation values.

  17. Frequencies of digits, divergence points, and Schmidt games

    International Nuclear Information System (INIS)

    Olsen, L.

    2009-01-01

    Sets of divergence points, i.e. numbers x (or tuples of numbers) for which the limiting frequency of a given string of N-adic digits of x fails to exist, have recently attracted huge interest in the literature. In this paper we consider sets of simultaneous divergence points, i.e. numbers x (or tuples of numbers) for which the limiting frequencies of all strings of N-adic digits of x fail to exist. We show that many natural sets of simultaneous divergence points are (α, β)-wining sets in the sense of the Schmidt game. As an application we obtain lower bounds for the Hausdorff dimension of these sets.

  18. Structure of UV divergences in maximally supersymmetric gauge theories

    Science.gov (United States)

    Kazakov, D. I.; Borlakov, A. T.; Tolkachev, D. M.; Vlasenko, D. E.

    2018-06-01

    We consider the UV divergences up to sub-subleading order for the four-point on-shell scattering amplitudes in D =8 supersymmetric Yang-Mills theory in the planar limit. We trace how the leading, subleading, etc divergences appear in all orders of perturbation theory. The structure of these divergences is typical for any local quantum field theory independently on renormalizability. We show how the generalized renormalization group equations allow one to evaluate the leading, subleading, etc. contributions in all orders of perturbation theory starting from one-, two-, etc. loop diagrams respectively. We focus then on subtraction scheme dependence of the results and show that in full analogy with renormalizable theories the scheme dependence can be absorbed into the redefinition of the couplings. The only difference is that the role of the couplings play dimensionless combinations like g2s2 or g2t2, where s and t are the Mandelstam variables.

  19. To be liked versus respected: Divergent goals in interracial interactions.

    Science.gov (United States)

    Bergsieker, Hilary B; Shelton, J Nicole; Richeson, Jennifer A

    2010-08-01

    Pervasive representations of Blacks and Latinos as unintelligent and of Whites as racist may give rise to divergent impression management goals in interracial interactions. We present studies showing that in interracial interactions racial minorities seek to be respected and seen as competent more than Whites do, whereas Whites seek to be liked and seen as moral more than racial minorities do. These divergent impression management goals are reflected in Whites' and racial minorities' self-report responses (Studies 1a, 1b, 2, and 4) and behaviors (Studies 3a and 3b). Divergent goals are observed in pre-existing relationships (Study 2), as well as in live interactions (Studies 3a, 3b, and 4), and are associated with higher levels of negative other-directed affect (Study 4). Implications of these goals for interracial communication and misunderstandings are discussed.

  20. Genetic divergence in sesame based on morphological and agronomic traits

    Directory of Open Access Journals (Sweden)

    Nair Helena Castro Arriel

    2007-01-01

    Full Text Available The evaluation of diversity in germplasm collections is important for both plant breeders and germplasmcurators to optimize the use of the variability available. Diversity can be estimated by different genetic markers. The purposeof this study was to estimate the genetic divergence of 30 morphological and agronomic traits in 108 sesame genotypes bymultivariate analysis. The Cole-Rodgers index was used to establish the dissimilarity matrices. The principal componentanalysis identified the traits that contributed most to the divergence and the genotypes were clustered by Tocher’s optimization.Despite the narrow genetic basis, the markers were efficient to characterize the genotypes and identify the most similar groupsor duplicate and divergent genotypes. Greatest variation was found for the traits number of capsules per plant and grain yield.

  1. Geographical data structures supporting regional analysis

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  2. Tanzanian food origins and protected geographical indications

    DEFF Research Database (Denmark)

    John, Innocensia Festo; Egelyng, Henrik; Lokina, Azack

    2016-01-01

    As the world's population is constantly growing, food security will remain on the policy Agenda, particularly in Africa. At the same time, global food systems experience a new wave focusing on local foods and food sovereignty featuring high quality food products of verifiable geographical origin...... of food origin products in Tanzania that have potential for GI certification. The hypothesis was that there are origin products in Tanzania whose unique characteristics are linked to the area of production. Geographical indications can be useful policy instruments contributing to food security...... the diversity of supply of natural and unique quality products and so contribute to enhanced food security....

  3. Does niche divergence accompany allopatric divergence in Aphelocoma jays as predicted under ecological speciation? Insights from tests with niche models.

    Science.gov (United States)

    McCormack, John E; Zellmer, Amanda J; Knowles, L Lacey

    2010-05-01

    The role of ecology in the origin of species has been the subject of long-standing interest to evolutionary biologists. New sources of spatially explicit ecological data allow for large-scale tests of whether speciation is associated with niche divergence or whether closely related species tend to be similar ecologically (niche conservatism). Because of the confounding effects of spatial autocorrelation of environmental variables, we generate null expectations for niche divergence for both an ecological-niche modeling and a multivariate approach to address the question: do allopatrically distributed taxa occupy similar niches? In a classic system for the study of niche evolution--the Aphelocoma jays--we show that there is little evidence for niche divergence among Mexican Jay (A. ultramarina) lineages in the process of speciation, contrary to previous results. In contrast, Aphelocoma species that exist in partial sympatry in some regions show evidence for niche divergence. Our approach is widely applicable to the many cases of allopatric lineages in the beginning stages of speciation. These results do not support an ecological speciation model for Mexican Jay lineages because, in most cases, the allopatric environments they occupy are not significantly more divergent than expected under a null model.

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

    Science.gov (United States)

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

    2003-09-01

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

  5. Robust Covariance Estimators Based on Information Divergences and Riemannian Manifold

    Directory of Open Access Journals (Sweden)

    Xiaoqiang Hua

    2018-03-01

    Full Text Available This paper proposes a class of covariance estimators based on information divergences in heterogeneous environments. In particular, the problem of covariance estimation is reformulated on the Riemannian manifold of Hermitian positive-definite (HPD matrices. The means associated with information divergences are derived and used as the estimators. Without resorting to the complete knowledge of the probability distribution of the sample data, the geometry of the Riemannian manifold of HPD matrices is considered in mean estimators. Moreover, the robustness of mean estimators is analyzed using the influence function. Simulation results indicate the robustness and superiority of an adaptive normalized matched filter with our proposed estimators compared with the existing alternatives.

  6. Bubble Divergences: Sorting out Topology from Cell Structure

    Science.gov (United States)

    Bonzom, Valentin; Smerlak, Matteo

    2012-02-01

    We conclude our analysis of bubble divergences in the flat spinfoam model. In [arXiv:1008.1476] we showed that the divergence degree of an arbitrary two-complex Gamma can be evaluated exactly by means of twisted cohomology. Here, we specialize this result to the case where Gamma is the two-skeleton of the cell decomposition of a pseudomanifold, and sharpen it with a careful analysis of the cellular and topological structures involved. Moreover, we explain in detail how this approach reproduces all the previous powercounting results for the Boulatov-Ooguri (colored) tensor models, and sheds light on algebraic-topological aspects of Gurau's 1/N expansion.

  7. Zimmermann's forest formula, infrared divergences and the QCD beta function

    Directory of Open Access Journals (Sweden)

    Franz Herzog

    2018-01-01

    Full Text Available We review Zimmermann's forest formula, which solves Bogoliubov's recursive R-operation for the subtraction of ultraviolet divergences in perturbative Quantum Field Theory. We further discuss a generalisation of the R-operation which subtracts besides ultraviolet also Euclidean infrared divergences. This generalisation, which goes under the name of the R⁎-operation, can be used efficiently to compute renormalisation constants. We will discuss several results obtained by this method with focus on the QCD beta function at five loops as well as the application to hadronic Higgs boson decay rates at N4LO. This article summarizes a talk given at the Wolfhart Zimmermann Memorial Symposium.

  8. Divergence from factorizable distributions and matroid representations by partitions

    Czech Academy of Sciences Publication Activity Database

    Matúš, František

    2009-01-01

    Roč. 55, č. 12 (2009), s. 5375-5381 ISSN 0018-9448 R&D Projects: GA AV ČR IAA100750603; GA ČR GA201/04/0393 Institutional research plan: CEZ:AV0Z10750506 Keywords : Information divergence * relative entropy * Shannon entropy * exponential family * hierarchical model * log-linear model * contingency table * Gibbs distribution * matroid representation * secret sharing scheme * maximum likelihood. Subject RIV: BA - General Mathematics Impact factor: 2.357, year: 2009 http://library.utia.cas.cz/separaty/2009/MTR/matus-divergence from factorizable distributions and matroid representations by partitions.pdf

  9. O Cabimento dos Embargos de Divergência

    OpenAIRE

    LOURENCO, S. R.

    2012-01-01

    A presente pesquisa objetiva demonstrar os embargos de divergência com enfoque nos elementos processuais do cabimento de tal modalidade recursal em nosso ordenamento jurídico. Para tanto, investigaremos os aspectos gerais dos embargos de divergência, a partir da análise dos elementos históricos enquanto a criação do instituto, como também sua finalidade e classificação no ordenamento jurídico brasileiro. Após, analisaremos o requisito de admissibilidade do cabimento dos embargo...

  10. Ultraviolet divergences in higher dimensional supersymmetric Yang-Mills theories

    International Nuclear Information System (INIS)

    Howe, P.S.; Stelle, K.S.

    1984-01-01

    We determine the loop orders for the onset of allowed ultra-violet divergences in higher dimensional supersymmetric Yang-Mills theories. Cancellations are controlled by the non-renormalization theorems for the linearly realizable supersymmetries and by the requirement that counterterms display the full non-linear supersymmetries when the classical equations of motion are imposed. The first allowed divergences in the maximal super Yang-Mills theories occur at four loops in five dimensions, three loops in six dimensions and two loops in seven dimensions. (orig.)

  11. Asymptotic states and infrared divergences in gauge theories

    International Nuclear Information System (INIS)

    Butler, D.R.

    1981-01-01

    The gauge theories, Gravity and QCD are shown to be infrared finite to a non-trival order by a generalization of the coherent state approach. The asymptotic Hamiltonian operator is used, along with a mathematical theorem by Magnus, to specify a S-operator and to show cancellation of infrared divergences at the amplitude level. This procedure is exemplified in Gravity to third order and applied to QCD for leading order divergences to fifth order in the coupling constant. Dimensional regularization is used to isolate the infrared singularities in QCD. The sections on Gravity include a derivation of the infrared structure of the propagators for a massive particle and the graviton

  12. An ancient divergence among the bacteria. [methanogenic phylogeny

    Science.gov (United States)

    Balch, W. E.; Magrum, L. J.; Fox, G. E.; Wolfe, R. S.; Woese, C. R.

    1977-01-01

    The 16S ribosomal RNZs from two species of met methanogenic bacteria, the mesophile Methanobacterium ruminantium and the thermophile Methanobacterium thermoautotrophicum, have been characterized in terms of the oligonucleotides produced by digestion with T1 ribonuclease. These two organisms are found to be sufficiently related that they can be considered members of the same genus or family. However, they bear only slight resemblance to 'typical' Procaryotic genera; such as Escherichia, Bacillus and Anacystis. The divergence of the methanogenic bacteria from other bacteria may be the most ancient phylogenetic event yet detected - antedating considerably the divergence of the blue green algal line for example, from the main bacterial line.

  13. Yellow Rust Epidemics Worldwide Were Caused by Pathogen Races from Divergent Genetic Lineages

    Science.gov (United States)

    Ali, Sajid; Rodriguez-Algaba, Julian; Thach, Tine; Sørensen, Chris K.; Hansen, Jens G.; Lassen, Poul; Nazari, Kumarse; Hodson, David P.; Justesen, Annemarie F.; Hovmøller, Mogens S.

    2017-01-01

    We investigated whether the recent worldwide epidemics of wheat yellow rust were driven by races of few clonal lineage(s) or populations of divergent races. Race phenotyping of 887 genetically diverse Puccinia striiformis isolates sampled in 35 countries during 2009–2015 revealed that these epidemics were often driven by races from few but highly divergent genetic lineages. PstS1 was predominant in North America; PstS2 in West Asia and North Africa; and both PstS1 and PstS2 in East Africa. PstS4 was prevalent in Northern Europe on triticale; PstS5 and PstS9 were prevalent in Central Asia; whereas PstS6 was prevalent in epidemics in East Africa. PstS7, PstS8 and PstS10 represented three genetic lineages prevalent in Europe. Races from other lineages were in low frequencies. Virulence to Yr9 and Yr27 was common in epidemics in Africa and Asia, while virulence to Yr17 and Yr32 were prevalent in Europe, corresponding to widely deployed resistance genes. The highest diversity was observed in South Asian populations, where frequent recombination has been reported, and no particular race was predominant in this area. The results are discussed in light of the role of invasions in shaping pathogen population across geographical regions. The results emphasized the lack of predictability of emergence of new races with high epidemic potential, which stresses the need for additional investments in population biology and surveillance activities of pathogens on global food crops, and assessments of disease vulnerability of host varieties prior to their deployment at larger scales. PMID:28676811

  14. Genomic patterns of nucleotide diversity in divergent populations of U.S. weedy rice

    Directory of Open Access Journals (Sweden)

    Olsen Kenneth M

    2010-06-01

    Full Text Available Abstract Background Weedy rice (red rice, a conspecific weed of cultivated rice (Oryza sativa L., is a significant problem throughout the world and an emerging threat in regions where it was previously absent. Despite belonging to the same species complex as domesticated rice and its wild relatives, the evolutionary origins of weedy rice remain unclear. We use genome-wide patterns of single nucleotide polymorphism (SNP variation in a broad geographic sample of weedy, domesticated, and wild Oryza samples to infer the origin and demographic processes influencing U.S. weedy rice evolution. Results We find greater population structure than has been previously reported for U.S. weedy rice, and that the multiple, genetically divergent populations have separate origins. The two main U.S. weedy rice populations share genetic backgrounds with cultivated O. sativa varietal groups not grown commercially in the U.S., suggesting weed origins from domesticated ancestors. Hybridization between weedy groups and between weedy rice and local crops has also led to the evolution of distinct U.S. weedy rice populations. Demographic simulations indicate differences among the main weedy groups in the impact of bottlenecks on their establishment in the U.S., and in the timing of divergence from their cultivated relatives. Conclusions Unlike prior research, we did not find unambiguous evidence for U.S. weedy rice originating via hybridization between cultivated and wild Oryza species. Our results demonstrate the potential for weedy life-histories to evolve directly from within domesticated lineages. The diverse origins of U.S. weedy rice populations demonstrate the multiplicity of evolutionary forces that can influence the emergence of weeds from a single species complex.

  15. Yellow Rust Epidemics Worldwide Were Caused by Pathogen Races from Divergent Genetic Lineages

    Directory of Open Access Journals (Sweden)

    Sajid Ali

    2017-06-01

    Full Text Available We investigated whether the recent worldwide epidemics of wheat yellow rust were driven by races of few clonal lineage(s or populations of divergent races. Race phenotyping of 887 genetically diverse Puccinia striiformis isolates sampled in 35 countries during 2009–2015 revealed that these epidemics were often driven by races from few but highly divergent genetic lineages. PstS1 was predominant in North America; PstS2 in West Asia and North Africa; and both PstS1 and PstS2 in East Africa. PstS4 was prevalent in Northern Europe on triticale; PstS5 and PstS9 were prevalent in Central Asia; whereas PstS6 was prevalent in epidemics in East Africa. PstS7, PstS8 and PstS10 represented three genetic lineages prevalent in Europe. Races from other lineages were in low frequencies. Virulence to Yr9 and Yr27 was common in epidemics in Africa and Asia, while virulence to Yr17 and Yr32 were prevalent in Europe, corresponding to widely deployed resistance genes. The highest diversity was observed in South Asian populations, where frequent recombination has been reported, and no particular race was predominant in this area. The results are discussed in light of the role of invasions in shaping pathogen population across geographical regions. The results emphasized the lack of predictability of emergence of new races with high epidemic potential, which stresses the need for additional investments in population biology and surveillance activities of pathogens on global food crops, and assessments of disease vulnerability of host varieties prior to their deployment at larger scales.

  16. A convergence/divergence schema to identify impacts: The case of the Palo Verde nuclear generating station

    International Nuclear Information System (INIS)

    Pasqualetti, M.J.

    1984-01-01

    Until fairly recently, geographers have contributed only slightly to research on nuclear power plants. Most studies have dealt with ''site selection,'' though lately topics including socioeconomics, waste disposal, and emergency preparedness, have been addressed. Currently NRC-mandated investigations into many of the impacts of nuclear power plants tend to focus on local effects, but these often are not detailed and are only during the early planning stages. Little attention continues to be paid to questions of socioeconomic impacts and land use changes during or after construction. This limited approach is neither necessary nor imaginative, cohesive nor wise, because it fails to encompass or probe an appropriately wide geographical range of possible contributions. This traditionally small and parochial sphere of inquiry can be expanded by using the conceptual framework of convergence and divergence. Suggested examples include land use changes in value or function in association with various nuclear facilities, transportation and socioeconomic factors associated with the complexities of the nuclear fuel cycle, and the exportation of fuel and the nuclear fuel cycle, and the exportation of fuel and technology. The application of such a geographical perspective in the study of PVNGS illustrates the influence (often distant and unrecognized) which can follow a local decision to build a nuclear power plant

  17. Combining Land Capability Evaluation, Geographic Information ...

    African Journals Online (AJOL)

    Combining Land Capability Evaluation, Geographic Information Systems, AnD Indigenous Technologies for Soil Conservation in Northern Ethiopia. ... Land capability and land use status were established following the procedures of a modified treatment-oriented capability classification using GIS. The case study ...

  18. Geometric algorithms for delineating geographic regions

    NARCIS (Netherlands)

    Reinbacher, I.

    2006-01-01

    Everyone of us is used to geographical regions like the south of Utrecht, the dutch Randstad, or the mountainous areas of Austria. Some of these regions have crisp, fixed boundaries like Utrecht or Austria. Others, like the dutch Randstad and the Austrian mountains, have no such boundaries and are

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

    Science.gov (United States)

    Noguera-Urbano, Elkin A; Escalante, Tania

    2014-03-01

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

  20. Europeans among themselves: Geographical and linguistic stereotypes

    NARCIS (Netherlands)

    Mamadouh, V.D.; Dąbrowska, A.; Pisarek, W.; Stickel, G.

    2017-01-01

    Stereotypes can be studied from the perspective of political geography and critical geopolitics as part of geographical imaginations, in other words those geopolitical representations that help us make sense of the world around us. They necessarily frame our perception of ongoing events, and inform

  1. Using Educational Tourism in Geographical Education

    Science.gov (United States)

    Prakapiene, Dalia; Olberkyte, Loreta

    2013-01-01

    The article analyses and defines the concept of educational tourism, presents the structure of the concept and looks into the opportunities for using educational tourism in geographical education. In order to reveal such opportunities a research was carried out in the Lithuanian national and regional parks using the qualitative method of content…

  2. Geographic distribution of wild potato species

    NARCIS (Netherlands)

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

    2001-01-01

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

  3. Geography and Geographical Information Science: Interdisciplinary Integrators

    Science.gov (United States)

    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…

  4. Geographic pathology of Helicobacter pylori gastritis

    NARCIS (Netherlands)

    Liu, Yi; Ponsioen, Cyriel I. J.; Xiao, Shu-Dong; Tytgat, Guido N. J.; ten Kate, Fiebo J. W.

    2005-01-01

    Background and aim. Helicobacter pylori is etiologically associated with gastritis and gastric cancer. There are significant geographical differences between the clinical manifestation of H. pylori infections. The aim of this study was to compare gastric mucosal histology in relation to age among H.

  5. Execution Management Solutions for Geographically Distributed Simulations

    NARCIS (Netherlands)

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

    2009-01-01

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

  6. Geographic Analysis of Neurosurgery Workforce in Korea.

    Science.gov (United States)

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

    2018-01-01

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

  7. Geographic disparity in kidney transplantation under KAS.

    Science.gov (United States)

    Zhou, Sheng; Massie, Allan B; Luo, Xun; Ruck, Jessica M; Chow, Eric K H; Bowring, Mary G; Bae, Sunjae; Segev, Dorry L; Gentry, Sommer E

    2017-12-12

    The Kidney Allocation System fundamentally altered kidney allocation, causing a substantial increase in regional and national sharing that we hypothesized might impact geographic disparities. We measured geographic disparity in deceased donor kidney transplant (DDKT) rate under KAS (6/1/2015-12/1/2016), and compared that with pre-KAS (6/1/2013-12/3/2014). We modeled DSA-level DDKT rates with multilevel Poisson regression, adjusting for allocation factors under KAS. Using the model we calculated a novel, improved metric of geographic disparity: the median incidence rate ratio (MIRR) of transplant rate, a measure of DSA-level variation that accounts for patient casemix and is robust to outlier values. Under KAS, MIRR was 1.75 1.81 1.86 for adults, meaning that similar candidates across different DSAs have a median 1.81-fold difference in DDKT rate. The impact of geography was greater than the impact of factors emphasized by KAS: having an EPTS score ≤20% was associated with a 1.40-fold increase (IRR =  1.35 1.40 1.45 , P geographic disparities with KAS (P = .3). Despite extensive changes to kidney allocation under KAS, geography remains a primary determinant of access to DDKT. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

  8. The National Geographic Society's Teaching Geography Project.

    Science.gov (United States)

    Bockenhauer, Mark H.

    1993-01-01

    Contends that the National Geographic Society's Teaching Geography Project is an inservice teacher education success story. Describes the origins, objectives, and development of the project. Summarizes the impact of the project and contends that its success is the result of the workshop format and guided practice in instructional strategies. (CFR)

  9. GEOGRAPHERS AND ECOSYSTEMS: A POINT OF VIEW

    African Journals Online (AJOL)

    are fearful of tackling it, mainly because they have never studied ecology or any of the pure sciences. Most of these geographers are trained in the arts disciplines and thus feel at a disadvantage even when confronted only by a 'jargon' which is un- familiar. They perceive themselves as being inade- quate and are unhappy ...

  10. The Geographic Extent of Global Supply Chains

    DEFF Research Database (Denmark)

    Machikita, Tomohiro; Ueki, Yasushi

    2012-01-01

    We study the extent to which inter-firm relationships are locally concentrated and what determines firm differences in geographic proximity to domestic or foreign suppliers and customers. From micro-data on selfreported customer and supplier data of firms in Indonesia, the Philippines, Thailand, ...

  11. Geographical information modelling for land resource survey

    NARCIS (Netherlands)

    Bruin, de S.

    2000-01-01

    The increasing popularity of geographical information systems (GIS) has at least three major implications for land resources survey. Firstly, GIS allows alternative and richer representation of spatial phenomena than is possible with the traditional paper map. Secondly, digital technology has

  12. Teaching Geographic Field Methods Using Paleoecology

    Science.gov (United States)

    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…

  13. Groundwater quality mapping using geographic information system ...

    African Journals Online (AJOL)

    Spatial variations in ground water quality in the corporation area of Gulbarga City located in the northern part of Karnataka State, India, have been studied using geographic information system (GIS) technique. GIS, a tool which is used for storing, analyzing and displaying spatial data is also used for investigating ground ...

  14. Formal Ontologies and Uncertainty. In Geographical Knowledge

    Directory of Open Access Journals (Sweden)

    Matteo Caglioni

    2014-05-01

    Full Text Available Formal ontologies have proved to be a very useful tool to manage interoperability among data, systems and knowledge. In this paper we will show how formal ontologies can evolve from a crisp, deterministic framework (ontologies of hard knowledge to new probabilistic, fuzzy or possibilistic frameworks (ontologies of soft knowledge. This can considerably enlarge the application potential of formal ontologies in geographic analysis and planning, where soft knowledge is intrinsically linked to the complexity of the phenomena under study.  The paper briefly presents these new uncertainty-based formal ontologies. It then highlights how ontologies are formal tools to define both concepts and relations among concepts. An example from the domain of urban geography finally shows how the cause-to-effect relation between household preferences and urban sprawl can be encoded within a crisp, a probabilistic and a possibilistic ontology, respectively. The ontology formalism will also determine the kind of reasoning that can be developed from available knowledge. Uncertain ontologies can be seen as the preliminary phase of more complex uncertainty-based models. The advantages of moving to uncertainty-based models is evident: whether it is in the analysis of geographic space or in decision support for planning, reasoning on geographic space is almost always reasoning with uncertain knowledge of geographic phenomena.

  15. Ontology-based geographic data set integration

    NARCIS (Netherlands)

    Uitermark, H.T.J.A.; Uitermark, Harry T.; Oosterom, Peter J.M.; Mars, Nicolaas; Molenaar, Martien; Molenaar, M.

    1999-01-01

    In order to develop a system to propagate updates we investigate the semantic and spatial relationships between independently produced geographic data sets of the same region (data set integration). The goal of this system is to reduce operator intervention in update operations between corresponding

  16. Geographic variation in gorilla limb bones.

    Science.gov (United States)

    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

  17. Deep divergences and extensive phylogeographic structure in a clade of lowland tropical salamanders

    Directory of Open Access Journals (Sweden)

    Rovito Sean M

    2012-12-01

    Full Text Available Abstract Background The complex geological history of Mesoamerica provides the opportunity to study the impact of multiple biogeographic barriers on population differentiation. We examine phylogeographic patterns in a clade of lowland salamanders (Bolitoglossa subgenus Nanotriton using two mitochondrial genes and one nuclear gene. We use several phylogeographic analyses to infer the history of this clade and test hypotheses regarding the geographic origin of species and location of genetic breaks within species. We compare our results to those for other taxa to determine if historical events impacted different species in a similar manner. Results Deep genetic divergence between species indicates that they are relatively old, and two of the three widespread species show strong phylogeographic structure. Comparison of mtDNA and nuclear gene trees shows no evidence of hybridization or introgression between species. Isolated populations of Bolitoglossa rufescens from Los Tuxtlas region constitute a separate lineage based on molecular data and morphology, and divergence between Los Tuxtlas and other areas appears to predate the arrival of B. rufescens in other areas west of the Isthmus of Tehuantepec. The Isthmus appears responsible for Pliocene vicariance within B. rufescens, as has been shown for other taxa. The Motagua-Polochic fault system does not appear to have caused population vicariance, unlike in other systems. Conclusions Species of Nanotriton have responded to some major geological events in the same manner as other taxa, particularly in the case of the Isthmus of Tehuantepec. The deep divergence of the Los Tuxtlas populations of B. rufescens from other populations highlights the contribution of this volcanic system to patterns of regional endemism, and morphological differences observed in the Los Tuxtlas populations suggests that they may represent an undescribed species of Bolitoglossa. The absence of phylogeographic structure in B

  18. Rates of genomic divergence in humans, chimpanzees and their lice.

    Science.gov (United States)

    Johnson, Kevin P; Allen, Julie M; Olds, Brett P; Mugisha, Lawrence; Reed, David L; Paige, Ken N; Pittendrigh, Barry R

    2014-02-22

    The rate of DNA mutation and divergence is highly variable across the tree of life. However, the reasons underlying this variation are not well understood. Comparing the rates of genetic changes between hosts and parasite lineages that diverged at the same time is one way to begin to understand differences in genetic mutation and substitution rates. Such studies have indicated that the rate of genetic divergence in parasites is often faster than that of their hosts when comparing single genes. However, the variation in this relative rate of molecular evolution across different genes in the genome is unknown. We compared the rate of DNA sequence divergence between humans, chimpanzees and their ectoparasitic lice for 1534 protein-coding genes across their genomes. The rate of DNA substitution in these orthologous genes was on average 14 times faster for lice than for humans and chimpanzees. In addition, these rates were positively correlated across genes. Because this correlation only occurred for substitutions that changed the amino acid, this pattern is probably produced by similar functional constraints across the same genes in humans, chimpanzees and their ectoparasites.

  19. Micropolar Fluids Using B-spline Divergence Conforming Spaces

    KAUST Repository

    Sarmiento, Adel; Garcia, Daniel; Dalcin, Lisandro; Collier, Nathan; Calo, Victor M.

    2014-01-01

    The divergence free formulation was used to guarantee an accurate solution of the flow. This formulation was implemented using the framework PetIGA as a basis, using its parallel stuctures to achieve high scalability. The results of the square heat driven cavity test case are in good agreement with those reported earlier.

  20. Divergent apparent temperature sensitivity of terrestrial ecosystem respiration

    Science.gov (United States)

    Bing Song; Shuli Niu; Ruise Luo; Yiqi Luo; Jiquan Chen; Guirui Yu; Janusz Olejnik; Georg Wohlfahrt; Gerard Kiely; Ako Noormets; Leonardo Montagnani; Alessandro Cescatti; Vincenzo Magliulo; Beverly Elizabeth Law; Magnus Lund; Andrej Varlagin; Antonio Raschi; Matthias Peichl; Mats B. Nilsson; Lutz Merbold

    2014-01-01

    Recent studies revealed convergent temperature sensitivity of ecosystem respiration (Re) within aquatic ecosystems and between terrestrial and aquatic ecosystems. We do not know yet whether various terrestrial ecosystems have consistent or divergent temperature sensitivity. Here, we synthesized 163 eddy covariance flux sites across the world and...

  1. Gauge-invariance and infrared divergences in the luminosity distance

    Energy Technology Data Exchange (ETDEWEB)

    Biern, Sang Gyu; Yoo, Jaiyul, E-mail: sgbiern@physik.uzh.ch, E-mail: jyoo@physik.uzh.ch [Center for Theoretical Astrophysics and Cosmology, Institute for Computational Science, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich (Switzerland)

    2017-04-01

    Measurements of the luminosity distance have played a key role in discovering the late-time cosmic acceleration. However, when accounting for inhomogeneities in the Universe, its interpretation has been plagued with infrared divergences in its theoretical predictions, which are in some cases used to explain the cosmic acceleration without dark energy. The infrared divergences in most calculations are artificially removed by imposing an infrared cut-off scale. We show that a gauge-invariant calculation of the luminosity distance is devoid of such divergences and consistent with the equivalence principle, eliminating the need to impose a cut-off scale. We present proper numerical calculations of the luminosity distance using the gauge-invariant expression and demonstrate that the numerical results with an ad hoc cut-off scale in previous calculations have negligible systematic errors as long as the cut-off scale is larger than the horizon scale. We discuss the origin of infrared divergences and their cancellation in the luminosity distance.

  2. Mass generation and the problem of seagull divergences

    International Nuclear Information System (INIS)

    Figueiredo, C. T.; Aguilar, A. C.

    2016-01-01

    The gluon mass generation is a purely non-perturbative effect, and the natural framework to study it in the continuum are the Schwinger-Dyson equations (SDEs) of the theory. At the level of the SDEs the generation of such a mass is associated with the existence of infrared finite solutions for the gluon propagator. From the theoretical point of view, the dynamical gluon mass generation has been traditionally plagued with seagull divergences. In this work, we will review how such divergences can be eliminated completely by virtue of a characteristic identity, valid in dimensional regularization. As a pedagogical example, we will first discuss in the context of scalar QED how it is possible to eliminate all seagull divergences, by triggering the aforementioned special identity, which enforces the masslessness of the photon. Then, we will discuss what happens in QCD and present an Ansatz for the three gluon vertex, which completely eliminates all seagull divergences and at same time allows for the possibility of a dynamical gluon mass generation. (paper)

  3. Sand-mediated divergence between shallow reef communities on ...

    African Journals Online (AJOL)

    Sand-mediated divergence between shallow reef communities on horizontal and vertical substrata in the western Indian Ocean. SN Porter, GM Branch, KJ Sink. Abstract. Distinctions are rarely made between vertical and horizontal surfaces when assessing reef community composition, yet physical differences are expected ...

  4. Speciation in rapidly diverging systems: lessons from Lake Malawi.

    Science.gov (United States)

    Danley, P D; Kocher, T D

    2001-05-01

    Rapid evolutionary radiations provide insight into the fundamental processes involved in species formation. Here we examine the diversification of one such group, the cichlid fishes of Lake Malawi, which have radiated from a single ancestor into more than 400 species over the past 700 000 years. The phylogenetic history of this group suggests: (i) that their divergence has proceeded in three major bursts of cladogenesis; and (ii) that different selective forces have dominated each cladogenic event. The first episode resulted in the divergence of two major lineages, the sand- and rock-dwellers, each adapted to a major benthic macrohabitat. Among the rock-dwellers, competition for trophic resources then drove a second burst of cladogenesis, which resulted in the differentiation of trophic morphology. The third episode of cladogenesis is associated with differentiation of male nuptial colouration, most likely in response to divergent sexual selection. We discuss models of speciation in relation to this observed pattern. We advocate a model, divergence with gene flow, which reconciles the disparate selective forces responsible for the diversification of this group and suggest that the nonadaptive nature of the tertiary episode has significantly contributed to the extraordinary species richness of this group.

  5. Determining divergence times with a protein clock: update and reevaluation

    Science.gov (United States)

    Feng, D. F.; Cho, G.; Doolittle, R. F.; Bada, J. L. (Principal Investigator)

    1997-01-01

    A recent study of the divergence times of the major groups of organisms as gauged by amino acid sequence comparison has been expanded and the data have been reanalyzed with a distance measure that corrects for both constraints on amino acid interchange and variation in substitution rate at different sites. Beyond that, the availability of complete genome sequences for several eubacteria and an archaebacterium has had a great impact on the interpretation of certain aspects of the data. Thus, the majority of the archaebacterial sequences are not consistent with currently accepted views of the Tree of Life which cluster the archaebacteria with eukaryotes. Instead, they are either outliers or mixed in with eubacterial orthologs. The simplest resolution of the problem is to postulate that many of these sequences were carried into eukaryotes by early eubacterial endosymbionts about 2 billion years ago, only very shortly after or even coincident with the divergence of eukaryotes and archaebacteria. The strong resemblances of these same enzymes among the major eubacterial groups suggest that the cyanobacteria and Gram-positive and Gram-negative eubacteria also diverged at about this same time, whereas the much greater differences between archaebacterial and eubacterial sequences indicate these two groups may have diverged between 3 and 4 billion years ago.

  6. Divergent Explanatory Production (DEP): The Relationship between Resilience and Creativity

    Science.gov (United States)

    Hernández, Óscar Sánchez; Méndez, Francisco Xavier; Garber, Judy

    2015-01-01

    Introduction: The aim of the study is to describe and analyze a new test and construct, Divergent Explanatory Production (DEP), defined as the ability to observe adverse situations from various points of view. At the theoretical level, it is a bridge between the reformulated model of learned helplessness (as a resilience model), and creative…

  7. Gauge-invariance and infrared divergences in the luminosity distance

    International Nuclear Information System (INIS)

    Biern, Sang Gyu; Yoo, Jaiyul

    2017-01-01

    Measurements of the luminosity distance have played a key role in discovering the late-time cosmic acceleration. However, when accounting for inhomogeneities in the Universe, its interpretation has been plagued with infrared divergences in its theoretical predictions, which are in some cases used to explain the cosmic acceleration without dark energy. The infrared divergences in most calculations are artificially removed by imposing an infrared cut-off scale. We show that a gauge-invariant calculation of the luminosity distance is devoid of such divergences and consistent with the equivalence principle, eliminating the need to impose a cut-off scale. We present proper numerical calculations of the luminosity distance using the gauge-invariant expression and demonstrate that the numerical results with an ad hoc cut-off scale in previous calculations have negligible systematic errors as long as the cut-off scale is larger than the horizon scale. We discuss the origin of infrared divergences and their cancellation in the luminosity distance.

  8. The equational theory of prebisimilarity over basic CCS with divergence

    NARCIS (Netherlands)

    Aceto, L.; Capobianco, S.; Ingólfsdóttir, A.; Luttik, B.

    2008-01-01

    This paper studies the equational theory of prebisimilarity, a bisimulation-based preorder introduced by Hennessy and Milner in the early 1980s, over basic CCS with the divergent process O. It is well known that prebisimilarity affords a finite ground-complete axiomatization over this language; this

  9. Stimulating Divergent Thinking in Junior High Career Education.

    Science.gov (United States)

    Ranke, Charlotte; Champoux, Ellen M.

    1981-01-01

    Describes a middle school career-oriented teaching unit with emphasis on teaching for divergent thinking. The unit provides hands-on opportunities for eighth-grade students to explore careers using the knowledge and skills developed in their home economics class. The careers are restaurant management, hospitality service, and interior design. (CT)

  10. Divergence time estimates of mammals from molecular clocks and ...

    Indian Academy of Sciences (India)

    Prakash

    2009-10-30

    Oct 30, 2009 ... In the last decade and a half, mammalian phylogeny and lineage divergence .... not the sudden availability of ecological niches following the KTB mass .... fish fauna, ostracods, and palynofossils (Singh et al. 2006;. Prasad et al. ... tendons and hence the functional adaptations of the animal during its life and ...

  11. Transcutaneous vagus nerve stimulation (tVNS) enhances divergent thinking.

    Science.gov (United States)

    Colzato, Lorenza S; Ritter, Simone M; Steenbergen, Laura

    2018-03-01

    Creativity is one of the most important cognitive skills in our complex and fast-changing world. Previous correlative evidence showed that gamma-aminobutyric acid (GABA) is involved in divergent but not convergent thinking. In the current study, a placebo/sham-controlled, randomized between-group design was used to test a causal relation between vagus nerve and creativity. We employed transcutaneous vagus nerve stimulation (tVNS), a novel non-invasive brain stimulation technique to stimulate afferent fibers of the vagus nerve and speculated to increase GABA levels, in 80 healthy young volunteers. Creative performance was assessed in terms of divergent thinking (Alternate Uses Task) and convergent thinking tasks (Remote Associates Test, Creative Problem Solving Task, Idea Selection Task). Results demonstrate active tVNS, compared to sham stimulation, enhanced divergent thinking. Bayesian analysis reported the data to be inconclusive regarding a possible effect of tVNS on convergent thinking. Therefore, our findings corroborate the idea that the vagus nerve is causally involved in creative performance. Even thought we did not directly measure GABA levels, our results suggest that GABA (likely to be increased in active tVNS condition) supports the ability to select among competing options in high selection demand (divergent thinking) but not in low selection demand (convergent thinking). Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. The loop expansion as a divergent-power-series expansion

    International Nuclear Information System (INIS)

    Murai, N.

    1981-01-01

    The loop expansion should be divergent, possibly an asymptotic one, in the Euclidean path integral formulation. This consideration is important in applications of the symmetric and mass-independent renormalization. The [1,1] Pade approximant is calculated in a PHI 4 model. Its classical vacua may be not truely stable for nonzero coupling constant. (author)

  13. Ground state energies from converging and diverging power series expansions

    International Nuclear Information System (INIS)

    Lisowski, C.; Norris, S.; Pelphrey, R.; Stefanovich, E.; Su, Q.; Grobe, R.

    2016-01-01

    It is often assumed that bound states of quantum mechanical systems are intrinsically non-perturbative in nature and therefore any power series expansion methods should be inapplicable to predict the energies for attractive potentials. However, if the spatial domain of the Schrödinger Hamiltonian for attractive one-dimensional potentials is confined to a finite length L, the usual Rayleigh–Schrödinger perturbation theory can converge rapidly and is perfectly accurate in the weak-binding region where the ground state’s spatial extension is comparable to L. Once the binding strength is so strong that the ground state’s extension is less than L, the power expansion becomes divergent, consistent with the expectation that bound states are non-perturbative. However, we propose a new truncated Borel-like summation technique that can recover the bound state energy from the diverging sum. We also show that perturbation theory becomes divergent in the vicinity of an avoided-level crossing. Here the same numerical summation technique can be applied to reproduce the energies from the diverging perturbative sums.

  14. An asymptotic formula of the divergent bilateral basic hypergeometric series

    OpenAIRE

    Morita, Takeshi

    2012-01-01

    We show an asymptotic formula of the divergent bilateral basic hypergeometric series ${}_1\\psi_0 (a;-;q,\\cdot)$ with using the $q$-Borel-Laplace method. We also give the limit $q\\to 1-0$ of our asymptotic formula.

  15. Ground state energies from converging and diverging power series expansions

    Energy Technology Data Exchange (ETDEWEB)

    Lisowski, C.; Norris, S.; Pelphrey, R.; Stefanovich, E., E-mail: eugene-stefanovich@usa.net; Su, Q.; Grobe, R.

    2016-10-15

    It is often assumed that bound states of quantum mechanical systems are intrinsically non-perturbative in nature and therefore any power series expansion methods should be inapplicable to predict the energies for attractive potentials. However, if the spatial domain of the Schrödinger Hamiltonian for attractive one-dimensional potentials is confined to a finite length L, the usual Rayleigh–Schrödinger perturbation theory can converge rapidly and is perfectly accurate in the weak-binding region where the ground state’s spatial extension is comparable to L. Once the binding strength is so strong that the ground state’s extension is less than L, the power expansion becomes divergent, consistent with the expectation that bound states are non-perturbative. However, we propose a new truncated Borel-like summation technique that can recover the bound state energy from the diverging sum. We also show that perturbation theory becomes divergent in the vicinity of an avoided-level crossing. Here the same numerical summation technique can be applied to reproduce the energies from the diverging perturbative sums.

  16. Divergent synthesis and optoelectronic properties of oligodiacetylene building blocks

    NARCIS (Netherlands)

    Pilzak, G.S.; Lagen, van B.; Sudhölter, E.J.R.; Zuilhof, H.

    2008-01-01

    A new and divergent synthetic route to oligodiacetylene (ODA) building blocks has been developed via Sonogashira reactions under a reductive atmosphere. These central building blocks provide a new way for rapid preparation of long ODAs. In addition, we report on their optoelectronic properties which

  17. Navier–Stokes flow in converging–diverging distensible tubes

    Directory of Open Access Journals (Sweden)

    Taha Sochi

    2015-09-01

    Full Text Available We use a method based on the lubrication approximation in conjunction with a residual-based mass-continuity iterative solution scheme to compute the flow rate and pressure field in distensible converging–diverging tubes for Navier–Stokes fluids. We employ an analytical formula derived from a one-dimensional version of the Navier–Stokes equations to describe the underlying flow model that provides the residual function. This formula correlates the flow rate to the boundary pressures in straight cylindrical elastic tubes with constant-radius. We validate our findings by the convergence toward a final solution with fine discretization as well as by comparison to the Poiseuille-type flow in its convergence toward analytic solutions found earlier in rigid converging–diverging tubes. We also tested the method on limiting special cases of cylindrical elastic tubes with constant-radius where the numerical solutions converged to the expected analytical solutions. The distensible model has also been endorsed by its convergence toward the rigid Poiseuille-type model with increasing the tube wall stiffness. Lubrication-based one-dimensional finite element method was also used for verification. In this investigation five converging–diverging geometries are used for demonstration, validation and as prototypes for modeling converging–diverging geometries in general.

  18. Functional Analysis of HIV/AIDS Stigma: Consensus or Divergence?

    Science.gov (United States)

    Hosseinzadeh, Hassan; Hossain, Syeda Zakia

    2011-01-01

    Functional theory proposes that attitudes may serve a variety of purposes for individuals. This study aimed to determine whether stigmatized attitudes toward HIV/AIDS serve the same function for all (consensus function) or serve different functions for different individuals (divergence function) by assessing various aspects of HIV/AIDS stigma…

  19. When can stress facilitate divergence by altering time to flowering?

    OpenAIRE

    Jordan, Crispin Y.; Ally, Dilara; Hodgins, Kathryn A.

    2015-01-01

    Abstract Stressors and heterogeneity are ubiquitous features of natural environments, and theory suggests that when environmental qualities alter flowering schedules through phenotypic plasticity, assortative mating can result that promotes evolutionary divergence. Therefore, it is important to determine whether common ecological stressors induce similar changes in flowering time. We review previous studies to determine whether two important stressors, water restriction and herbivory, induce ...

  20. When can stress facilitate divergence by altering time to flowering?

    Science.gov (United States)

    Jordan, Crispin Y; Ally, Dilara; Hodgins, Kathryn A

    2015-12-01

    Stressors and heterogeneity are ubiquitous features of natural environments, and theory suggests that when environmental qualities alter flowering schedules through phenotypic plasticity, assortative mating can result that promotes evolutionary divergence. Therefore, it is important to determine whether common ecological stressors induce similar changes in flowering time. We review previous studies to determine whether two important stressors, water restriction and herbivory, induce consistent flowering time responses among species; for example, how often do water restriction and herbivory both delay flowering? We focus on the direction of change in flowering time, which affects the potential for divergence in heterogeneous environments. We also tested whether these stressors influenced time to flowering and nonphenology traits using Mimulus guttatus. The literature review suggests that water restriction has variable effects on flowering time, whereas herbivory delays flowering with exceptional consistency. In the Mimulus experiment, low water and herbivory advanced and delayed flowering, respectively. Overall, our results temper theoretical predictions for evolutionary divergence due to habitat-induced changes in flowering time; in particular, we discuss how accounting for variation in the direction of change in flowering time can either increase or decrease the potential for divergence. In addition, we caution against adaptive interpretations of stress-induced phenology shifts.

  1. Genetic Divergence in Ducks for Economic Traits | Kalita | Animal ...

    African Journals Online (AJOL)

    D2 Statistics was used to identify the genetic divergence in 4 groups of duck, namely Khaki Campbell (KC), Desi (D), Khaki Campbell x Desi (KC x D) and Desi x Khaki Campbell (D x KC) reared under rural conditions at the Siphajar, Darrang District, Assam, India. The study showed that both Khaki Campbell and Desi or ...

  2. Micropolar Fluids Using B-spline Divergence Conforming Spaces

    KAUST Repository

    Sarmiento, Adel

    2014-06-06

    We discretized the two-dimensional linear momentum, microrotation, energy and mass conservation equations from micropolar fluids theory, with the finite element method, creating divergence conforming spaces based on B-spline basis functions to obtain pointwise divergence free solutions [8]. Weak boundary conditions were imposed using Nitsche\\'s method for tangential conditions, while normal conditions were imposed strongly. Once the exact mass conservation was provided by the divergence free formulation, we focused on evaluating the differences between micropolar fluids and conventional fluids, to show the advantages of using the micropolar fluid model to capture the features of complex fluids. A square and an arc heat driven cavities were solved as test cases. A variation of the parameters of the model, along with the variation of Rayleigh number were performed for a better understanding of the system. The divergence free formulation was used to guarantee an accurate solution of the flow. This formulation was implemented using the framework PetIGA as a basis, using its parallel stuctures to achieve high scalability. The results of the square heat driven cavity test case are in good agreement with those reported earlier.

  3. The odd couple: Diverging paths in language policy and educational ...

    African Journals Online (AJOL)

    This paper examines the divergences between what educational policy calls for in South African schools with regard to language and learning and what takes place in schools. It argues that South African constitutional and education policy statements employ an idea of languages as bound entities and systems, and ...

  4. Analysis of growth characteristics in short-term divergently selected ...

    African Journals Online (AJOL)

    weeks of age body weight in divergent lines of Japanese quail. Growth curves for both sexes within each selection group resembled the general sigmoid shape of a typical growth curve. Gompertz model curves and the observed growth curves were ...

  5. Divergence-Free Wavelets on the Hypercube : General Boundary Conditions

    NARCIS (Netherlands)

    Stevenson, R.

    2016-01-01

    On the n-dimensional hypercube, for given k∈N, wavelet Riesz bases are constructed for the subspace of divergence-free vector fields of the Sobolev space Hk((0,1)n)n with general homogeneous Dirichlet boundary conditions, including slip or no-slip boundary conditions. Both primal and suitable dual

  6. Factor analysis models via I-divergence optimization

    NARCIS (Netherlands)

    Finesso, L.; Spreij, P.

    2016-01-01

    Given a positive definite covariance matrix Σˆ of dimension n, we approximate it with a covariance of the form HH⊤+D, where H has a prescribed number k0 is diagonal. The quality of the approximation is gauged by the I-divergence between the zero mean normal laws with covariances

  7. Geographical conceptualization of quality of life

    Directory of Open Access Journals (Sweden)

    Murgaš František

    2016-12-01

    Full Text Available The conceptualization of quality of life in terms of geography is based on two assumptions. The first assumption is that the quality of life consists of two dimensions: subjective and objective. The subjective is known as ‘well-being’, while the objective is the proposed term ‘quality of place’. The second assumption is based on the recognition that quality of life is always a spatial dimension. The concept of quality of life is closely linked with the concept of a good life; geographers enriched this concept by using the term ‘good place’ as a place in which the conditions are created for a good life. The quality of life for individuals in terms of a good place overlaps with the quality of life in society, namely the societal quality of life. The geographical conceptualisation of quality of life is applied to settlements within the city of Liberec.

  8. A Systems Perspective on Volunteered Geographic Information

    Directory of Open Access Journals (Sweden)

    Victoria Fast

    2014-12-01

    Full Text Available Volunteered geographic information (VGI is geographic information collected by way of crowdsourcing. However, the distinction between VGI as an information product and the processes that create VGI is blurred. Clearly, the environment that influences the creation of VGI is different than the information product itself, yet most literature treats them as one and the same. Thus, this research is motivated by the need to formalize and standardize the systems that support the creation of VGI. To this end, we propose a conceptual framework for VGI systems, the main components of which—project, participants, and technical infrastructure—form an environment conducive to the creation of VGI. Drawing on examples from OpenStreetMap, Ushahidi, and RinkWatch, we illustrate the pragmatic relevance of these components. Applying a system perspective to VGI allows us to better understand the components and functionality needed to effectively create VGI.

  9. Geographical information systems and computer cartography

    CERN Document Server

    Jones, Chris B

    2014-01-01

    A concise text presenting the fundamental concepts in Geographical Information Systems (GIS), emphasising an understanding of techniques in management, analysis and graphic display of spatial information. Divided into five parts - the first part reviews the development and application of GIS, followed by a summary of the characteristics and representation of geographical information. It concludes with an overview of the functions provided by typical GIS systems. Part Two introduces co-ordinate systems and map projections, describes methods for digitising map data and gives an overview of remote sensing. Part Three deals with data storage and database management, as well as specialised techniques for accessing spatial data. Spatial modelling and analytical techniques for decision making form the subject of Part Four, while the final part is concerned with graphical representation, emphasising issues of graphics technology, cartographic design and map generalisation.

  10. SOLID WASTE: PRESENCE AND THREATIN GEOGRAPHICAL SPACE

    Directory of Open Access Journals (Sweden)

    Clesley Maria Tavares do Nascimento

    2017-12-01

    Full Text Available This article deals with the trajectory of the solid waste in different historical periods, configuring them as a constructive element of geographical space. The intention to bring the theme from the timeline perspective, is marked out in the conviction of the inseparability of the categories of space and time and its importance in understanding a geographical phenomenon. The methodological support of this research relied on the documentary type of research involving literature, consultation of secondary sources such as books, academic journals, dissertations and theses on the subject. The results presented and discussed in this paper indicated that the production of waste is adjacent to historical time, reflects societies and techniques that generated them, and is a permanent part of the dialectical process of spatial formation.

  11. Do geographically isolated wetlands influence landscape functions?

    OpenAIRE

    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

    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 bo...

  12. Geographic Analysis of Neurosurgery Workforce in Korea

    Science.gov (United States)

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

    2018-01-01

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

  13. Geographic assistance of decontamination strategy elaboration

    International Nuclear Information System (INIS)

    Davydchuk, V.; Arapis, G.

    1996-01-01

    Those who elaborates the strategy of decontamination of vast territories is to take into consideration the heterogeneity of such elements of landscape as relief, lithology, humidity and types of soils and, vegetation, both on local and regional level. Geographic assistance includes evaluation of efficacy of decontamination technologies in different natural conditions, identification of areas of their effective application and definition of ecological damage, estimation of balances of the radionuclides in the landscapes to create background of the decontamination strategy

  14. Geographic Analysis of the Radiation Oncology Workforce

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  15. U Plant Geographic Zone Cleanup Prototype

    International Nuclear Information System (INIS)

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

    2006-01-01

    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

  16. Using Educational Tourism in Geographical Education

    OpenAIRE

    PRAKAPIENĖ, Dalia; OLBERKYTĖ, Loreta

    2014-01-01

    The article analyses and defines the concept of educational tourism, presents the structure of the concept and looks into the opportunities for using educational tourism in geographical education. In order to reveal such opportunities a research was carried out in the Lithuanian national and regional parks using the qualitative method of content analysis and the quantitative method of questionnaire survey. The authors of the research identified the educational excursion activities conducted i...

  17. Estimating the accuracy of geographical imputation

    Directory of Open Access Journals (Sweden)

    Boscoe Francis P

    2008-01-01

    Full Text Available Abstract Background To reduce the number of non-geocoded cases researchers and organizations sometimes include cases geocoded to postal code centroids along with cases geocoded with the greater precision of a full street address. Some analysts then use the postal code to assign information to the cases from finer-level geographies such as a census tract. Assignment is commonly completed using either a postal centroid or by a geographical imputation method which assigns a location by using both the demographic characteristics of the case and the population characteristics of the postal delivery area. To date no systematic evaluation of geographical imputation methods ("geo-imputation" has been completed. The objective of this study was to determine the accuracy of census tract assignment using geo-imputation. Methods Using a large dataset of breast, prostate and colorectal cancer cases reported to the New Jersey Cancer Registry, we determined how often cases were assigned to the correct census tract using alternate strategies of demographic based geo-imputation, and using assignments obtained from postal code centroids. Assignment accuracy was measured by comparing the tract assigned with the tract originally identified from the full street address. Results Assigning cases to census tracts using the race/ethnicity population distribution within a postal code resulted in more correctly assigned cases than when using postal code centroids. The addition of age characteristics increased the match rates even further. Match rates were highly dependent on both the geographic distribution of race/ethnicity groups and population density. Conclusion Geo-imputation appears to offer some advantages and no serious drawbacks as compared with the alternative of assigning cases to census tracts based on postal code centroids. For a specific analysis, researchers will still need to consider the potential impact of geocoding quality on their results and evaluate

  18. Geographic Analysis of the Radiation Oncology Workforce

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-04-01

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

  19. Globalization in history : a geographical perspective

    OpenAIRE

    Crafts, N. F. R.; Venables, Anthony

    2001-01-01

    This paper argues that a geographical perspectie is fundamental to understanding comparative economic development in the context of globalization. Central to this view is the role of agglomeration in productivity performance; size and location matter. The tools of the new economic geography are used to illuminate important epidsodes when the relative position of major eeconmies radically changed; the rise of the United States at the beginning and of East Asia at the end of the twentieth centu...

  20. PEDIATRIC FITNESS: SECULAR TRENDS AND GEOGRAPHIC VARIABILITY

    Directory of Open Access Journals (Sweden)

    Grant R. Tomkinson

    2007-06-01

    Full Text Available DESCRIPTION This book describes and discusses children's physical capacity in terms of aerobic and anaerobic power generation according to secular trends and geographic variability. PURPOSE To discuss the controversial issue of whether present day's children and adolescents are fitter than their equals of the past and whether they are fitter if they live in the more prosperous countries. AUDIENCE Pediatricians, medical practitioners, physical educators, exercise and/or sport scientists, exercise physiologists, personal trainers and graduate students in relevant fields will find this book helpful when dealing with contemporary trends and geographic variability in pediatric fitness. FEATURES The volume starts by examining the general picture on children fitness by the editors. The individual chapter's authors discuses the data gathered since the late 1950s on secular trends and geographic changeability in aerobic and anaerobic pediatric fitness performances of children and adolescents from 23 countries in Africa, Asia, Australasia, Europe, the Middle East and North America. There are chapters proposing that there is proof that there has been a world-wide decline in pediatric aerobic performance in recent decades, relative stability in anaerobic performance, and that the best performing children come from northern and central Europe. In final chapters possible causes to that end are considered, including whether weakening in aerobic performance are the result of distributional or widespread declines, and whether increases in obesity alone can explain the failure in aerobic performance. ASSESSMENT The editors have assembled a volume of Medicine and Sports Science that is necessary and essential reading for all who are interested in understanding and improving the fitness of children. The readers will find useful information in this book on secular trends and geographic variability in pediatric fitness. I believe, the book will serve as a first

  1. Deterrence and Geographical Externalities in Auto Theft

    OpenAIRE

    Marco Gonzalez-Navarro

    2013-01-01

    Understanding the degree of geographical crime displacement is crucial for the design of crime prevention policies. This paper documents changes in automobile theft risk that were generated by the plausibly exogenous introduction of Lojack, a highly effective stolen vehicle recovery device, into a number of new Ford car models in some Mexican states, but not others. Lojack-equipped vehicles in Lojack-coverage states experienced a 48 percent reduction in theft risk due to deterrence effects. H...

  2. Variability of geographically distinct isolates of maize rayado fino virus in Latin America.

    Science.gov (United States)

    Hammond, R W; Kogel, R; Ramirez, P

    1997-12-01

    We have examined the molecular epidemiology of the leafhopper-borne maize rayado fino virus (MRFV) in Latin America. The coat protein gene and 3' non-translated region of 14 isolates of MRFV collected from Latin America and the United States were sequenced and phylogenetic relationships examined. The nucleotide sequence revealed remarkable conservation, with a sequence similarity of 88-99%. Phylogenetic analysis of sequence data obtained from a 633 bp fragment showed that MRFV has diverged into three main clusters, i.e. the geographically distinct northern and southern isolates and the Colombian isolates. Significant differences between the isolates collected from Colombia, previously named maize rayado colombiana virus, based upon differences in symptomatology and serological relationships to MRFV, and the other MRFV isolates, provides additional evidence supporting its designation as a unique strain of MRFV.

  3. Natural selection drives the fine-scale divergence of a coevolutionary arms race involving a long-mouthed weevil and its obligate host plant

    Directory of Open Access Journals (Sweden)

    Toju Hirokazu

    2009-01-01

    Full Text Available Abstract Background One of the major recent advances in evolutionary biology is the recognition that evolutionary interactions between species are substantially differentiated among geographic populations. To date, several authors have revealed natural selection pressures mediating the geographically-divergent processes of coevolution. How local, then, is the geographic structuring of natural selection in coevolutionary systems? Results I examined the spatial scale of a "geographic selection mosaic," focusing on a system involving a seed-predatory insect, the camellia weevil (Curculio camelliae, and its host plant, the Japanese camellia (Camellia japonica. In this system, female weevils excavate camellia fruits with their extremely-long mouthparts to lay eggs into seeds, while camellia seeds are protected by thick pericarps. Quantitative evaluation of natural selection demonstrated that thicker camellia pericarps are significantly favored in some, but not all, populations within a small island (Yakushima Island, Japan; diameter ca. 30 km. At the extreme, camellia populations separated by only several kilometers were subject to different selection pressures. Interestingly, in a population with the thickest pericarps, camellia individuals with intermediate pericarp thickness had relatively high fitness when the potential costs of producing thick pericarps were considered. Also importantly, some parameters of the weevil - camellia interaction such as the severity of seed infestation showed clines along temperature, suggesting the effects of climate on the fine-scale geographic differentiation of the coevolutionary processes. Conclusion These results show that natural selection can drive the geographic differentiation of interspecific interactions at surprisingly small spatial scales. Future studies should reveal the evolutionary/ecological outcomes of the "fine scale geographic mosaics" in biological communities.

  4. Divergência genética em linhagens de melancia Genetic divergence in watermelon lines

    Directory of Open Access Journals (Sweden)

    Flávio de França Souza

    2005-06-01

    Full Text Available A divergência genética entre 31 genótipos de melancia foi avaliada por meio da análise de variáveis canônicas e de técnicas de agrupamento (Tocher e método hierárquico de Ward baseadas na distância generalizada de Mahalanobis (D²ii'. Trinta linhagens, obtidas a partir de acessos coletados no Nordeste brasileiro e a cultivar 'Crimson Sweet' foram avaliadas quanto ao número de dias para o aparecimento da primeira flor masculina e da primeira flor feminina (NDM e NDF; número do nó da primeira flor masculina e da primeira flor feminina (NGM e NGF; número de frutos por planta (NFP; comprimento de rama principal (CRP; peso médio de fruto (PMF; teor de sólidos solúveis (TSS; diâmetro transversal e longitudinal do fruto (DTF e DLF e espessura média de casca (EMC. O experimento foi realizado em delineamento de blocos ao acaso com três repetições, compostas por parcelas de sete plantas. As características que mais contribuíram para a divergência entre as linhagens foram número de frutos por planta, diâmetro longitudinal, teor de sólidos solúveis e peso médio de fruto. Foram formados três grupos por meio do método de otimização de Tocher, três por meio do método hierárquico de Ward e quatro grupos pela dispersão gráfica baseada nas duas primeiras variáveis canônicas. Neste caso, o grupo I compôs-se de sete linhagens de Pernambuco e uma da Bahia; o grupo II reuniu todas as 21 linhagens do Maranhão; os grupos III e IV foram compostos pela linhagem 97-0247.008 (Pernambuco e pela cultivar Crimson Sweet, respectivamente. As linhagens 87-019.021 e 87-019.022 foram as mais semelhantes, enquanto a linhagem 87-019.023 e 'Crimson Sweet' apresentaram maior dissimilaridade pela distância generalizada Mahalanobis (D²ii'. Os cruzamentos mais promissores serão aqueles realizados entre Crimson Sweet e as linhagens do grupo II. Cruzamentos entre Crimson Sweet e as linhagens do grupo I serão interessantes para a obtenção de

  5. Geographically isolated wetlands: Rethinking a misnomer

    Science.gov (United States)

    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.

  6. GEOGRAPHICAL EDUCATION MEDIATIZATION AND MEDIASECURITY ISSUES

    Directory of Open Access Journals (Sweden)

    M. R. Arpentieva

    2017-01-01

    Full Text Available The article is devoted to the interaction of legal and moral development of media technologies in the context of geographical education. The article summarizes the experience of the theoretical analysis of mediatization in geographic education, the legal and moral aspects of the disorders and ways of their prevention and correction in the process of educational interaction between teacher and student, between student and teacher, mediated mediatechnologies. It is noted that geographical education in the modern world is education, which is closely associated with the use of media technologies. In other types of education the role of media technologies in improving the quality of education is less obvious, in the field of teaching and learning geography, it speaks very clearly. Therefore, the problems associated with its mediatization, are very important and their solution is particularly compelling. These issues are primarily associated with actively flowing social, economic, political and ideological crisis in many communities and countries of the Earth. Many of them as in the “mirror” are reflected in the sphere of high technologies, including media technologies. The article provides guidance and direction to the correction of violations at the individual and social levels.

  7. A Geographical Heuristic Routing Protocol for VANETs

    Science.gov (United States)

    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. Geographical assemblages of European raptors and owls

    Science.gov (United States)

    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.

  9. Ontology for cell-based geographic information

    Science.gov (United States)

    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.

  10. Genomic signatures of geographic isolation and natural selection in coral reef fishes.

    Science.gov (United States)

    Gaither, Michelle R; Bernal, Moisés A; Coleman, Richard R; Bowen, Brian W; Jones, Shelley A; Simison, W Brian; Rocha, Luiz A

    2015-04-01

    The drivers of speciation remain among the most controversial topics in evolutionary biology. Initially, Darwin emphasized natural selection as a primary mechanism of speciation, but the architects of the modern synthesis largely abandoned that view in favour of divergence by geographic isolation. The balance between selection and isolation is still at the forefront of the evolutionary debate, especially for the world's tropical oceans where biodiversity is high, but isolating barriers are few. Here, we identify the drivers of speciation in Pacific reef fishes of the genus Acanthurus by comparative genome scans of two peripheral populations that split from a large Central-West Pacific lineage at roughly the same time. Mitochondrial sequences indicate that populations in the Hawaiian Archipelago and the Marquesas Islands became isolated approximately 0.5 Ma. The Hawaiian lineage is morphologically indistinguishable from the widespread Pacific form, but the Marquesan form is recognized as a distinct species that occupies an unusual tropical ecosystem characterized by upwelling, turbidity, temperature fluctuations, algal blooms and little coral cover. An analysis of 3737 SNPs reveals a strong signal of selection at the Marquesas, with 59 loci under disruptive selection including an opsin Rh2 locus. While both the Hawaiian and Marquesan populations indicate signals of drift, the former shows a weak signal of selection that is comparable with populations in the Central-West Pacific. This contrast between closely related lineages reveals one population diverging due primarily to geographic isolation and genetic drift, and the other achieving taxonomic species status under the influence of selection. © 2015 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  11. Direct sequencing of mitochondrial DNA detects highly divergent haplotypes in blue marlin (Makaira nigricans).

    Science.gov (United States)

    Finnerty, J R; Block, B A

    1992-06-01

    We were able to differentiate between species of billfish (Istiophoridae family) and to detect considerable intraspecific variation in the blue marlin (Makaira nigricans) by directly sequencing a polymerase chain reaction (PCR)-amplified, 612-bp fragment of the mitochondrial cytochrome b gene. Thirteen variable nucleotide sites separated blue marlin (n = 26) into 7 genotypes. On average, these genotypes differed by 5.7 base substitutions. A smaller sample of swordfish from an equally broad geographic distribution displayed relatively little intraspecific variation, with an average of 1.3 substitutions separating different genotypes. A cladistic analysis of blue marlin cytochrome b variants indicates two major divergent evolutionary lines within the species. The frequencies of these two major evolutionary lines differ significantly between Atlantic and Pacific ocean basins. This finding is important given that the Atlantic stocks of blue marlin are considered endangered. Migration from the Pacific can help replenish the numbers of blue marlin in the Atlantic, but the loss of certain mitochondrial DNA haplotypes in the Atlantic due to overfishing probably could not be remedied by an influx of Pacific fish because of their absence in the Pacific population. Fishery management strategies should attempt to preserve the genetic diversity within the species. The detection of DNA sequence polymorphism indicates the utility of PCR technology in pelagic fishery genetics.

  12. Effects of heterosis for yield and yield components obtained by crossing divergent alfalfa populations

    Directory of Open Access Journals (Sweden)

    Katić Slobodan

    2010-01-01

    Full Text Available When breeding alfalfa for yield performance, it is necessary to use high-yielding parents obtained by different breeding methods. The assumption at the onset of this research was that crossing highest-yielding domestic cultivars with divergent populations from geographically distant breeding centers could result in the expression of heterotic effects in their hybrids contributing to increased alfalfa yield. The objective of this study was to determine yield and yield components and heterotic effects in hybrid progenies obtained by crossing the domestic cultivars NS Banat ZMS II and NS Mediana ZMS V with the cultivars Pella, Dolichi and Hyliki from Greece, UMSS 2001 from Bolivia and Jogeva 118 from Estonia in two series. The field trial planted in 2006, included 13 F1 hybrids and 6 of 7 initial parents in both series. Heterotic effects for yields of forage and hay were observed in 4 combinations (C NS Banat ZMS II x E Hyliki; C NS Banat ZMS II x E UMSS 2001; C NS Mediana ZMS V x E Hyliki; C NS Mediana ZMS V x E Dolichi. The populations that exhibited heterosis in a set of crossings are recommended for use as parent components for development of high-yielding synthetic alfalfa cultivars. .

  13. Genetic Divergence and Chemotype Diversity in the Fusarium Head Blight Pathogen Fusarium poae.

    Science.gov (United States)

    Vanheule, Adriaan; De Boevre, Marthe; Moretti, Antonio; Scauflaire, Jonathan; Munaut, Françoise; De Saeger, Sarah; Bekaert, Boris; Haesaert, Geert; Waalwijk, Cees; van der Lee, Theo; Audenaert, Kris

    2017-08-23

    Fusarium head blight is a disease caused by a complex of Fusarium species. F. poae is omnipresent throughout Europe in spite of its low virulence. In this study, we assessed a geographically diverse collection of F. poae isolates for its genetic diversity using AFLP (Amplified Fragment Length Polymorphism). Furthermore, studying the mating type locus and chromosomal insertions, we identified hallmarks of both sexual recombination and clonal spread of successful genotypes in the population. Despite the large genetic variation found, all F. poae isolates possess the nivalenol chemotype based on Tri7 sequence analysis. Nevertheless, Tri gene clusters showed two layers of genetic variability. Firstly, the Tri1 locus was highly variable with mostly synonymous mutations and mutations in introns pointing to a strong purifying selection pressure. Secondly, in a subset of isolates, the main trichothecene gene cluster was invaded by a transposable element between Tri5 and Tri6 . To investigate the impact of these variations on the phenotypic chemotype, mycotoxin production was assessed on artificial medium. Complex blends of type A and type B trichothecenes were produced but neither genetic variability in the Tri genes nor variability in the genome or geography accounted for the divergence in trichothecene production. In view of its complex chemotype, it will be of utmost interest to uncover the role of trichothecenes in virulence, spread and survival of F. poae .

  14. The impact of divergence time on the nature of population structure: an example from Iceland.

    Directory of Open Access Journals (Sweden)

    Alkes L Price

    2009-06-01

    Full Text Available The Icelandic population has been sampled in many disease association studies, providing a strong motivation to understand the structure of this population and its ramifications for disease gene mapping. Previous work using 40 microsatellites showed that the Icelandic population is relatively homogeneous, but exhibits subtle population structure that can bias disease association statistics. Here, we show that regional geographic ancestries of individuals from Iceland can be distinguished using 292,289 autosomal single-nucleotide polymorphisms (SNPs. We further show that subpopulation differences are due to genetic drift since the settlement of Iceland 1100 years ago, and not to varying contributions from different ancestral populations. A consequence of the recent origin of Icelandic population structure is that allele frequency differences follow a null distribution devoid of outliers, so that the risk of false positive associations due to stratification is minimal. Our results highlight an important distinction between population differences attributable to recent drift and those arising from more ancient divergence, which has implications both for association studies and for efforts to detect natural selection using population differentiation.

  15. Structural divergence of chromosomes between malaria vectors Anopheles lesteri and Anopheles sinensis

    Directory of Open Access Journals (Sweden)

    Jiangtao Liang

    2016-11-01

    Full Text Available Abstract Background Anopheles lesteri and Anopheles sinensis are two major malaria vectors in China and Southeast Asia. They are dramatically different in terms of geographical distribution, host preference, resting habitats, and other traits associated with ecological adaptation and malaria transmission. Both species belong to the Anopheles hyrcanus group, but the extent of genetic differences between them is not well understood. To provide an effective way to differentiate between species and to find useful markers for population genetics studies, we performed a comparative cytogenetic analysis of these two malaria vectors. Results Presented here is a standard cytogenetic map for An. lesteri, and a comparative analysis of chromosome structure and gene order between An. lesteri and An. sinensis. Our results demonstrate that much of the gene order on chromosomes X and 2 was reshuffled between the two species. However, the banding pattern and the gene order on chromosome 3 appeared to be conserved. We also found two new polymorphic inversions, 2Lc and 3Rb, in An. lesteri, and we mapped the breakpoints of these two inversions on polytene chromosomes. Conclusions Our results demonstrate the extent of structural divergence of chromosomes between An. lesteri and An. sinensis, and provide a new taxonomic cytogenetic tool to distinguish between these two species. Polymorphic inversions of An. lesteri could serve as markers for studies of the population structure and ecological adaptations of this major malaria vector.

  16. Yellow Rust Epidemics Worldwide Were Caused by Pathogen Races from Divergent Genetic Lineages

    DEFF Research Database (Denmark)

    Ali, Sajid; Rodriguez Algaba, Julian; Thach, Tine

    2017-01-01

    population across geographical regions. The results emphasized the lack of predictability of emergence of new races with high epidemic potential, which stresses the need for additional investments in population biology and surveillance activities of pathogens on global food crops, and assessments of disease...... that these epidemics were often driven by races from few but highly divergent genetic lineages. PstS1 was predominant in North America; PstS2 in West Asia and North Africa; and both PstS1 and PstS2 in East Africa. PstS4 was prevalent in Northern Europe on triticale; PstS5 and PstS9 were prevalent in Central Asia......; whereas PstS6 was prevalent in epidemics in East Africa. PstS7, PstS8 and PstS10 represented three genetic lineages prevalent in Europe. Races from other lineages were in low frequencies. Virulence to Yr9 and Yr27 was common in epidemics in Africa and Asia, while virulence to Yr17 and Yr32 were prevalent...

  17. Pythium aphanidermatum Infection Following Combat Trauma

    Science.gov (United States)

    2011-10-01

    reactive pupils and bibasilar crackles upon lung auscultation. Wound examination revealed complete exposure of the posterior thighs to the deep muscle layers...abdominal abscess formation, ventilator-associated pneumonias, and recurrent bacteremias. The patient died of multiorgan system failure 16 weeks after his

  18. Structure of rapidity divergences in multi-parton scattering soft factors

    Science.gov (United States)

    Vladimirov, Alexey

    2018-04-01

    We discuss the structure of rapidity divergences that are presented in the soft factors of transverse momentum dependent (TMD) factorization theorems. To provide the discussion on the most general level we consider soft factors for multi-parton scattering. We show that the rapidity divergences are result of the gluon exchanges with the distant transverse plane, and are structurally equivalent to the ultraviolet divergences. It allows to formulate and to prove the renormalization theorem for rapidity divergences. The proof is made with the help the conformal transformation which maps rapidity divergences to ultraviolet divergences. The theorem is the systematic form of the factorization of rapidity divergences, which is required for the definition of TMD parton distributions. In particular, the definition of multi parton distributions is presented. The equivalence of ultraviolet and rapidity divergences leads to the exact relation between soft and rapidity anomalous dimensions. Using this relation we derive the rapidity anomalous dimension at the three-loop order.

  19. Phylogeography and allopatric divergence of cypress species (Cupressus L. in the Qinghai-Tibetan Plateau and adjacent regions

    Directory of Open Access Journals (Sweden)

    Ciren Zhaxi

    2010-06-01

    Full Text Available Abstract Background Although allopatric speciation is viewed as the most common way in which species originate, allopatric divergence among a group of closely related species has rarely been examined at the population level through phylogeographic analysis. Here we report such a case study on eight putative cypress (Cupressus species, which each have a mainly allopatric distribution in the Qinghai-Tibetan Plateau (QTP and adjacent regions. The analysis involved sequencing three plastid DNA fragments (trnD-trnT, trnS-trnG and trnL-trnF in 371 individuals sampled from populations at 66 localities. Results Both phylogenetic and network analyses showed that most DNA haplotypes recovered or haplotype-clustered lineages resolved were largely species-specific. Across all species, significant phylogeographic structure (NST >GST, P C. duclouxiana and C. chengiana, which are distributed in the eastern QTP region, contained more haplotypes and higher diversity than five species with restricted distributions in the western highlands of the QTP. The remaining species, C. funebris, is widely cultivated and contained very little cpDNA diversity. Conclusions It is concluded that the formation of high mountain barriers separating deep valleys in the QTP and adjacent regions caused by various uplifts of the plateau since the early Miocene most likely promoted allopatric divergence in Cupressus by restricting gene flow and fixing local, species-specific haplotypes in geographically isolated populations. The low levels of intraspecific diversity present in most species might stem from population bottlenecks brought about by recurrent periods of unfavorable climate and more recently by the negative impacts of human activities on species' distributions. Our findings shed new light on the importance of geographical isolation caused by the uplift of the QTP on the development of high plant species diversity in the QTP biodiversity hotspot.

  20. Chromosomal diversity and molecular divergence among three undescribed species of Neacomys (Rodentia, Sigmodontinae separated by Amazonian rivers.

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    Willam Oliveira Da Silva

    Full Text Available The Neacomys genus (Rodentia, Sigmodontinae is distributed in the Amazon region, with some species limited to a single endemic area, while others may occur more widely. The number of species within the genus and their geographical boundaries are not known accurately, due to their high genetic diversity and difficulties in taxonomic identification. In this work we collected Neacomys specimens from both banks of the Tapajós River in eastern Amazon, and studied them using chromosome painting with whole chromosome probes of Hylaeamys megacephalus (HME; Rodentia, Sigmodontinae, and molecular analysis using haplotypes of mitochondrial genes COI and Cytb. Chromosome painting shows that Neacomys sp. A (NSP-A, 2n = 58/FN = 68 and Neacomys sp. B (NSP-B, 2n = 54/FN = 66 differ by 11 fusion/fission events, one translocation, four pericentric inversions and four heterochromatin amplification events. Using haplotypes of the concatenated mitochondrial genes COI and Cyt b, Neacomys sp. (2n = 58/FN = 64 and 70 shows a mean divergence of 6.2% for Neacomys sp. A and 9.1% for Neacomys sp. B, while Neacomys sp. A and Neacomys sp. B presents a medium nucleotide divergence of 7.4%. Comparisons were made with other published Neacomys data. The Tapajós and Xingu Rivers act as geographic barriers that define the distribution of these Neacomys species. Furthermore, our HME probes reveal four synapomorphies for the Neacomys genus (associations HME 20/[13,22]/4, 6a/21, [9,10]/7b/[9,10] and 12/[16,17] and demonstrate ancestral traits of the Oryzomyini tribe (HME 8a and 8b, 18 and 25 and Sigmodontinae subfamily (HME 15 and 24, which can be used as taxonomic markers for these groups.

  1. Chromosomal diversity and molecular divergence among three undescribed species of Neacomys (Rodentia, Sigmodontinae) separated by Amazonian rivers.

    Science.gov (United States)

    Oliveira Da Silva, Willam; Pieczarka, Julio Cesar; Ferguson-Smith, Malcolm Andrew; O'Brien, Patricia Caroline Mary; Mendes-Oliveira, Ana Cristina; Sampaio, Iracilda; Carneiro, Jeferson; Nagamachi, Cleusa Yoshiko

    2017-01-01

    The Neacomys genus (Rodentia, Sigmodontinae) is distributed in the Amazon region, with some species limited to a single endemic area, while others may occur more widely. The number of species within the genus and their geographical boundaries are not known accurately, due to their high genetic diversity and difficulties in taxonomic identification. In this work we collected Neacomys specimens from both banks of the Tapajós River in eastern Amazon, and studied them using chromosome painting with whole chromosome probes of Hylaeamys megacephalus (HME; Rodentia, Sigmodontinae), and molecular analysis using haplotypes of mitochondrial genes COI and Cytb. Chromosome painting shows that Neacomys sp. A (NSP-A, 2n = 58/FN = 68) and Neacomys sp. B (NSP-B, 2n = 54/FN = 66) differ by 11 fusion/fission events, one translocation, four pericentric inversions and four heterochromatin amplification events. Using haplotypes of the concatenated mitochondrial genes COI and Cyt b, Neacomys sp. (2n = 58/FN = 64 and 70) shows a mean divergence of 6.2% for Neacomys sp. A and 9.1% for Neacomys sp. B, while Neacomys sp. A and Neacomys sp. B presents a medium nucleotide divergence of 7.4%. Comparisons were made with other published Neacomys data. The Tapajós and Xingu Rivers act as geographic barriers that define the distribution of these Neacomys species. Furthermore, our HME probes reveal four synapomorphies for the Neacomys genus (associations HME 20/[13,22]/4, 6a/21, [9,10]/7b/[9,10] and 12/[16,17]) and demonstrate ancestral traits of the Oryzomyini tribe (HME 8a and 8b, 18 and 25) and Sigmodontinae subfamily (HME 15 and 24), which can be used as taxonomic markers for these groups.

  2. Divergence of perturbation theory in large scale structures

    Science.gov (United States)

    Pajer, Enrico; van der Woude, Drian

    2018-05-01

    We make progress towards an analytical understanding of the regime of validity of perturbation theory for large scale structures and the nature of some non-perturbative corrections. We restrict ourselves to 1D gravitational collapse, for which exact solutions before shell crossing are known. We review the convergence of perturbation theory for the power spectrum, recently proven by McQuinn and White [1], and extend it to non-Gaussian initial conditions and the bispectrum. In contrast, we prove that perturbation theory diverges for the real space two-point correlation function and for the probability density function (PDF) of the density averaged in cells and all the cumulants derived from it. We attribute these divergences to the statistical averaging intrinsic to cosmological observables, which, even on very large and "perturbative" scales, gives non-vanishing weight to all extreme fluctuations. Finally, we discuss some general properties of non-perturbative effects in real space and Fourier space.

  3. Little evidence for dynamic divergences in ultraviscous molecular liquids

    DEFF Research Database (Denmark)

    Hecksher, Tina; Nielsen, Albena; Olsen, Niels Boye

    2008-01-01

    The physics of the ultraviscous liquid phase preceding glass formation continues to pose major problems that remain unsolved. It is actively debated, for instance, whether the marked increase of the relaxation time reflects an underlying phase transition to a state of infinite relaxation time....... To elucidate the empirical evidence for this intriguing scenario, some of the most accurate relaxationtime data available for any class of ultraviscous liquids-those obtained by dielectric relaxation experiments on organic liquids just above the glass transition-were compiled. Analysis of data for 42 liquids...... shows that there is no compelling evidence for the Vogel-Fulcher-Tammann (VFT) prediction that the relaxation time diverges at a finite temperature.We conclude that theories with a dynamic divergence of the VFT formlack a direct experimental basis....

  4. Convergence and divergence, a concept for explaining drug actions.

    Science.gov (United States)

    Watanabe, Takehiko; Kamisaki, Yoshinori; Timmerman, Henk

    2004-10-01

    For the teaching and/or learning about drug actions and for the discovery and development of new drugs, it is important to understand how drugs act on living bodies. So far, there has been no clear description on the general principle of drug action in pharmacology textbooks. We propose two principles to depict the action mechanism of drugs. The first is that most, if not all, drugs act on proteins at the molecular level, that is, enzymes, receptors, ion channels, and transporters. The second is that a drug may cause divergent or convergent responses, resulting in changes of a physiological or pathological function of the human body. The concept of divergence and convergence can be used to explain the complex individuality of drug actions.

  5. Divergent biparietal diameter growth rates in twin pregnancies.

    Science.gov (United States)

    Houlton, M C

    1977-05-01

    Twenty-eight twin pregnancies were monitored by serial ultrasonic cephalometry from 30 or 31 weeks' gestation. The rates of growth of the individual twins as determined by biparietal diameters were similar in 11 cases (39%) and divergent in 17 (61%). When the rates of growth were divergent, the lesser rate was always below the mean for singleton pregnancies, and the incidence of small-for-gestational-age babies was 18 of 34 (53%). It was apparent that the greater the difference in biparietal diameters within the 2 weeks preceding delivery, the higher the risk of a small-for-gestation-age baby being delivered. No comment could be made on the growth rate prior to 28 weeks except that at diagnosis there was little or no difference in biparietal diameters.

  6. Divergent unprotected peptide macrocyclisation by palladium-mediated cysteine arylation.

    Science.gov (United States)

    Rojas, Anthony J; Zhang, Chi; Vinogradova, Ekaterina V; Buchwald, Nathan H; Reilly, John; Pentelute, Bradley L; Buchwald, Stephen L

    2017-06-01

    Macrocyclic peptides are important therapeutic candidates due to their improved physicochemical properties in comparison to their linear counterparts. Here we detail a method for a divergent macrocyclisation of unprotected peptides by crosslinking two cysteine residues with bis-palladium organometallic reagents. These synthetic intermediates are prepared in a single step from commercially available aryl bis-halides. Two bioactive linear peptides with cysteine residues at i , i + 4 and i , i + 7 positions, respectively, were cyclised to introduce a diverse array of aryl and bi-aryl linkers. These two series of macrocyclic peptides displayed similar linker-dependent lipophilicity, phospholipid affinity, and unique volume of distributions. Additionally, one of the bioactive peptides showed target binding affinity that was predominantly affected by the length of the linker. Collectively, this divergent strategy allowed rapid and convenient access to various aryl linkers, enabling the systematic evaluation of the effect of appending unit on the medicinal properties of macrocyclic peptides.

  7. Summation of Divergent Series and Zeldovich's Regularization Method

    International Nuclear Information System (INIS)

    Mur, V.D.; Pozdnyakov, S.G.; Popruzhenko, S.V.; Popov, V.S.

    2005-01-01

    A method for summing divergent series, including perturbation-theory series, is considered. This method is an analog of Zeldovich's regularization method in the theory of quasistationary states. It is shown that the method in question is more powerful than the well-known Abel and Borel methods, but that it is compatible with them (that is, it leads to the same value for the sum of a series). The constraints on the parameter domain that arise upon the removal of the regularization of divergent integrals by this method are discussed. The dynamical Stark shifts and widths of loosely bound s states in the field of a circularly polarized electromagnetic wave are calculated at various values of the Keldysh adiabaticity parameter and the multiquantum parameter

  8. Divergence-free MHD Simulations with the HERACLES Code

    Directory of Open Access Journals (Sweden)

    Vides J.

    2013-12-01

    Full Text Available Numerical simulations of the magnetohydrodynamics (MHD equations have played a significant role in plasma research over the years. The need of obtaining physical and stable solutions to these equations has led to the development of several schemes, all requiring to satisfy and preserve the divergence constraint of the magnetic field numerically. In this paper, we aim to show the importance of maintaining this constraint numerically. We investigate in particular the hyperbolic divergence cleaning technique applied to the ideal MHD equations on a collocated grid and compare it to the constrained transport technique that uses a staggered grid to maintain the property. The methods are implemented in the software HERACLES and several numerical tests are presented, where the robustness and accuracy of the different schemes can be directly compared.

  9. Relations between heat exchange and Rényi divergences

    Science.gov (United States)

    Wei, Bo-Bo

    2018-04-01

    In this work, we establish an exact relation which connects the heat exchange between two systems initialized in their thermodynamic equilibrium states at different temperatures and the Rényi divergences between the initial thermodynamic equilibrium state and the final nonequilibrium state of the total system. The relation tells us that the various moments of the heat statistics are determined by the Renyi divergences between the initial equilibrium state and the final nonequilibrium state of the global system. In particular the average heat exchange is quantified by the relative entropy between the initial equilibrium state and the final nonequilibrium state of the global system. The relation is applicable to both finite classical systems and finite quantum systems.

  10. Divergent series, summability and resurgence II simple and multiple summability

    CERN Document Server

    Loday-Richaud, Michèle

    2016-01-01

    Addressing the question how to “sum” a power series in one variable when it diverges, that is, how to attach to it analytic functions, the volume gives answers by presenting and comparing the various theories of k-summability and multisummability. These theories apply in particular to all solutions of ordinary differential equations. The volume includes applications, examples and revisits, from a cohomological point of view, the group of tangent-to-identity germs of diffeomorphisms of C studied in volume 1. With a view to applying the theories to solutions of differential equations, a detailed survey of linear ordinary differential equations is provided which includes Gevrey asymptotic expansions, Newton polygons, index theorems and Sibuya’s proof of the meromorphic classification theorem that characterizes the Stokes phenomenon for linear differential equations. This volume is the second of a series of three entitled Divergent Series, Summability and Resurgence. It is aimed at graduate students and res...

  11. Genetic divergence in nuclear genomes between populations of Fagus crenata along the Japan Sea and Pacific sides of Japan.

    Science.gov (United States)

    Hiraoka, Koichi; Tomaru, Nobuhiro

    2009-05-01

    Genetic diversity and structure in Fagus crenata were studied by analyzing 14 nuclear microsatellite loci in 23 populations distributed throughout the species' range. Although population differentiation was very low (F (ST) = 0.027; R (ST) = 0.041), both neighbor-joining tree and Bayesian clustering analyses provided clear evidence of genetic divergence between populations along the Japan Sea (Japan Sea lineage) and Pacific (Pacific lineage) sides of Japan, indicating that physical barriers to migration and gene flow, notably the mountain ranges separating the populations along the Japan Sea and Pacific sides, have promoted genetic divergence between these populations. The two lineages of the nuclear genome are generally consistent with those of the chloroplast genome detected in a previous study, with several discrepancies between the two genomes. Within-population genetic diversity was generally very high (average H (E) = 0.839), but decreased in a clinal fashion from southwest to northeast, largely among populations of the Japan Sea lineage. This geographical gradient may have resulted from the late-glacial and postglacial recolonization to the northeast, which led to a loss of within-population genetic diversity due to cumulative founder effects.

  12. East-west genetic differentiation in Musk Ducks (Biziura lobata) of Australia suggests late Pleistocene divergence at the Nullarbor Plain

    Science.gov (United States)

    Guay, P.-J.; Chesser, R.T.; Mulder, R.A.; Afton, A.D.; Paton, D.C.; McCracken, K.G.

    2010-01-01

    Musk Ducks (Biziura lobata) are endemic to Australia and occur as two geographically isolated populations separated by the Nullarbor Plain, a vast arid region in southern Australia. We studied genetic variation in Musk Duck populations at coarse (eastern versus western Australia) and fine scales (four sites within eastern Australia). We found significant genetic structure between eastern and western Australia in the mtDNA control region (??ST = 0. 747), one nuclear intron (??ST = 0.193) and eight microsatellite loci (FST = 0.035). In contrast, there was little genetic structure between Kangaroo Island and adjacent mainland regions within eastern Australia. One small population of Musk Ducks in Victoria (Lake Wendouree) differed from both Kangaroo Island and the remainder of mainland eastern Australia, possibly due to genetic drift exacerbated by inbreeding and small population size. The observed low pairwise distance between the eastern and western mtDNA lineages (0.36%) suggests that they diverged near the end of the Pleistocene, a period characterised by frequent shifts between wet and arid conditions in central Australia. Our genetic results corroborate the display call divergence and Mathews' (Austral Avian Record 2:83-107, 1914) subspecies classification, and confirm that eastern and western populations of Musk Duck are currently isolated from each other. ?? 2010 Springer Science+Business Media B.V.

  13. Genetic divergence of a sympatric lake-resident-anadromous three-spined stickleback Gasterosteus aculeatus species pair.

    Science.gov (United States)

    Drevecky, C J; Falco, R; Aguirre, W E

    2013-07-01

    The genetic relationship between sympatric, morphologically divergent populations of anadromous and lake-resident three-spined stickleback Gasterosteus aculeatus in the Jim Creek drainage of Cook Inlet, Alaska, was examined using microsatellite loci and mitochondrial d-loop sequence data. Resident samples differed substantially from sympatric anadromous samples in the Jim Creek drainage with the magnitude of the genetic divergence being similar to that between allopatric resident and anadromous populations in other areas. Resident samples were genetically similar within the Jim Creek drainage, as were the anadromous samples surveyed. Neighbour-joining and Structure cluster analysis grouped the samples into four genetic clusters by ecomorph (anadromous v. all resident) and geographic location of the resident samples (Jim Creek, Mat-Su and Kenai). There was no evidence of hybridization between resident and anadromous G. aculeatus in the Jim Creek drainage, which thus appear to be reproductively isolated. © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

  14. A rapid, strong, and convergent genetic response to urban habitat fragmentation in four divergent and widespread vertebrates.

    Directory of Open Access Journals (Sweden)

    Kathleen Semple Delaney

    2010-09-01

    Full Text Available Urbanization is a major cause of habitat fragmentation worldwide. Ecological and conservation theory predicts many potential impacts of habitat fragmentation on natural populations, including genetic impacts. Habitat fragmentation by urbanization causes populations of animals and plants to be isolated in patches of suitable habitat that are surrounded by non-native vegetation or severely altered vegetation, asphalt, concrete, and human structures. This can lead to genetic divergence between patches and in turn to decreased genetic diversity within patches through genetic drift and inbreeding.We examined population genetic patterns using microsatellites in four common vertebrate species, three lizards and one bird, in highly fragmented urban southern California. Despite significant phylogenetic, ecological, and mobility differences between these species, all four showed similar and significant reductions in gene flow over relatively short geographic and temporal scales. For all four species, the greatest genetic divergence was found where development was oldest and most intensive. All four animals also showed significant reduction in gene flow associated with intervening roads and freeways, the degree of patch isolation, and the time since isolation.Despite wide acceptance of the idea in principle, evidence of significant population genetic changes associated with fragmentation at small spatial and temporal scales has been rare, even in smaller terrestrial vertebrates, and especially for birds. Given the striking pattern of similar and rapid effects across four common and widespread species, including a volant bird, intense urbanization may represent the most severe form of fragmentation, with minimal effective movement through the urban matrix.

  15. The puzzle of Italian rice origin and evolution: determining genetic divergence and affinity of rice germplasm from Italy and Asia.

    Directory of Open Access Journals (Sweden)

    Xingxing Cai

    Full Text Available The characterization of genetic divergence and relationships of a set of germplasm is essential for its efficient applications in crop breeding and understanding of the origin/evolution of crop varieties from a given geographical region. As the largest rice producing country in Europe, Italy holds rice germplasm with abundant genetic diversity. Although Italian rice varieties and the traditional ones in particular have played important roles in rice production and breeding, knowledge concerning the origin and evolution of Italian traditional varieties is still limited. To solve the puzzle of Italian rice origin, we characterized genetic divergence and relationships of 348 rice varieties from Italy and Asia based on the polymorphisms of microsatellite fingerprints. We also included common wild rice O. rufipogon as a reference in the characterization. Results indicated relatively rich genetic diversity (H(e = 0.63-0.65 in Italian rice varieties. Further analyses revealed a close genetic relationship of the Italian traditional varieties with those from northern China, which provides strong genetic evidence for tracing the possible origin of early established rice varieties in Italy. These findings have significant implications for the rice breeding programs, in which appropriate germplasm can be selected from a given region and utilized for transferring unique genetic traits based on its genetic diversity and evolutionary relationships.

  16. Divergence of Cs-137 sources fluence used in brachytherapy

    International Nuclear Information System (INIS)

    Vianello, E.A.; Almeida, C.E. de

    1998-01-01

    In this work the experimental determination of correction factor for fluence divergence (kln) of linear Cs-137 sources CDCS J4, with Farmer ionization chamber model 2571 in a central and perpendicular plan to source axis, for distances range from 1 to 7 cm., has been presented. The experimental results were compared to calculating by Kondo and Randolph (1960) isotropic theory and Bielajew (1990) anisotropic theory. (Author)

  17. Real and metaphorical hunger: the case of The Divergent Trilogy

    OpenAIRE

    Paravano, Cristina

    2015-01-01

    The present contribution investigates how the issue of hunger becomes a means of expressing and communicating personal and social identity in Veronica Roth’s best seller trilogy Divergent (2011-13). Roth portrays a dystopian future developing a multifaceted concept of hunger, both real and figurative, and using food as a cultural metaphor. The trilogy is set in a post-apocalyptic Chicago, whose population is divided into five allegorical factions, according to a number of personal and social ...

  18. Divergence, recombination and retention of functionality during protein evolution

    Directory of Open Access Journals (Sweden)

    Xu Yanlong O

    2005-09-01

    Full Text Available Abstract We have only a vague idea of precisely how protein sequences evolve in the context of protein structure and function. This is primarily because structural and functional contexts are not easily predictable from the primary sequence, and evaluating patterns of evolution at individual residue positions is also difficult. As a result of increasing biodiversity in genomics studies, progress is being made in detecting context-dependent variation in substitution processes, but it remains unclear exactly what context-dependent patterns we should be looking for. To address this, we have been simulating protein evolution in the context of structure and function using lattice models of proteins and ligands (or substrates. These simulations include thermodynamic features of protein stability and population dynamics. We refer to this approach as 'ab initio evolution' to emphasise the fact that the equilibrium details of fitness distributions arise from the physical principles of the system and not from any preconceived notions or arbitrary mathematical distributions. Here, we present results on the retention of functionality in homologous recombinants following population divergence. A central result is that protein structure characteristics can strongly influence recombinant functionality. Exceptional structures with many sequence options evolve quickly and tend to retain functionality -- even in highly diverged recombinants. By contrast, the more common structures with fewer sequence options evolve more slowly, but the fitness of recombinants drops off rapidly as homologous proteins diverge. These results have implications for understanding viral evolution, speciation and directed evolutionary experiments. Our analysis of the divergence process can also guide improved methods for accurately approximating folding probabilities in more complex but realistic systems.

  19. [Phylogeny and divergence time estimation of Schizothoracinae fishes in Xinjiang].

    Science.gov (United States)

    Ayelhan, Haysa; Guo, Yan; Meng, Wei; Yang, Tianyan; Ma, Yanwu

    2014-10-01

    Based on combined data of mitochondrial COI, ND4 and 16S RNA genes, molecular phylogeny of 4 genera, 10 species or subspecies of Schizothoracinae fishes distributed in Xinjiang were analyzed. The molecular clock was calibrated by divergence time of Cyprininae and geological segregation event between the upper Yellow River and Qinghai Lake. Divergence time of Schizothoracinae fishes was calculated, and its relationship with the major geological events and the climate changes in surrounding areas of Tarim Basin was discussed. The results showed that genus Aspiorhynchus did not form an independent clade, but clustered with Schizothorax biddulphi and S. irregularis. Kimura 2-parameter model was used to calculate the genetic distance of COI gene, the genetic distance between genus Aspiorhynchus and Schizothorax did not reach genus level, and Aspiorhynchus laticeps might be a specialized species of genus Schizothorax. Cluster analysis showed a different result with morphological classification method, and it did not support the subgenus division of Schizothorax fishes. Divergence of two groups of primitive Schizothoracinae (8.18Ma) and divergence of Gymnodiptychus dybowskii and Diptychus maculates (7.67Ma) occurred in late Miocene, which might be related with the separation of Kunlun Mountain and north Tianshan Mountain River system that was caused by the uplift of Qinghai-Tibet Plateau and Tianshan Mountain, and the aridification of Tarim Basin. The terrain of Tarim Basin that was affected by Quaternary Himalayan movement was high in west but low in east, as a result, Lop Nor became the center of surrounding mountain rivers in Tarim Basin, which shaped the distribution pattern of genus Schizothorax.

  20. Existence and multiplicity of solutions for divergence type elliptic equations

    Directory of Open Access Journals (Sweden)

    Lin Zhao

    2011-03-01

    Full Text Available We establish the existence and multiplicity of weak solutions of a problem involving a uniformly convex elliptic operator in divergence form. We find one nontrivial solution by the mountain pass lemma, when the nonlinearity has a $(p-1$-superlinear growth at infinity, and two nontrivial solutions by minimization and mountain pass when the nonlinear term has a $(p-1$-sublinear growth at infinity.