WorldWideScience

Sample records for broad host distribution

  1. Spectral Decomposition of Broad-Line AGNs and Host Galaxies

    CERN Document Server

    Vanden Berk, Daniel E; Yip, C W; Schneider, D P; Connolly, A J; Burton, R E; Jester, S; Hall, P B; Szalay, A S; Brinkmann, J; Berk, Daniel E. Vanden; Shen, Jiajian; Yip, Ching-Wa; Schneider, Donald P.; Connolly, Andrew J.; Burton, Ross E.; Jester, Sebastian; Hall, Patrick B.; Szalay, Alex S.; Brinkmann, John

    2005-01-01

    Using an eigenspectrum decomposition technique, we separate the host galaxy from the broad line active galactic nucleus (AGN) in a set of 4666 spectra from the Sloan Digital Sky Survey (SDSS), from redshifts near zero up to about 0.75. The decomposition technique uses separate sets of galaxy and quasar eigenspectra to efficiently and reliably separate the AGN and host spectroscopic components. The technique accurately reproduces the host galaxy spectrum, its contributing fraction, and its classification. We show how the accuracy of the decomposition depends upon S/N, host galaxy fraction, and the galaxy class. Based on the eigencoefficients, the sample of SDSS broad-line AGN host galaxies spans a wide range of spectral types, but the distribution differs significantly from inactive galaxies. In particular, post-starburst activity appears to be much more common among AGN host galaxies. The luminosities of the hosts are much higher than expected for normal early-type galaxies, and their colors become increasing...

  2. Spectral decomposition of broad-line agns and host galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Vanden Berk, Daniel E.; Shen, Jiajian; /Penn State U., Astron. Astrophys.; Yip, Ching-Wa; /Pittsburgh U.; Schneider, Donald P.; /Penn State U., Astron. Astrophys.; Connolly,; /Pittsburgh U.; Burton, Ross E.; /Pittsburgh U. /Case Western Reserve U.; Jester, Sebastian; /Fermilab; Hall, Patrick B.; /York U., Canada; Szalay, Alex S.; /Johns Hopkins; Brinkmann, John; /Apache Point Observ.

    2005-09-01

    Using an eigenspectrum decomposition technique, we separate the host galaxy from the broad line active galactic nucleus (AGN) in a set of 4666 spectra from the Sloan Digital Sky Survey (SDSS), from redshifts near zero up to about 0.75. The decomposition technique uses separate sets of galaxy and quasar eigenspectra to efficiently and reliably separate the AGN and host spectroscopic components. The technique accurately reproduces the host galaxy spectrum, its contributing fraction, and its classification. We show how the accuracy of the decomposition depends upon S/N, host galaxy fraction, and the galaxy class. Based on the eigencoefficients, the sample of SDSS broad-line AGN host galaxies spans a wide range of spectral types, but the distribution differs significantly from inactive galaxies. In particular, post-starburst activity appears to be much more common among AGN host galaxies. The luminosities of the hosts are much higher than expected for normal early-type galaxies, and their colors become increasingly bluer than early-type galaxies with increasing host luminosity. Most of the AGNs with detected hosts are emitting at between 1% and 10% of their estimated Eddington luminosities, but the sensitivity of the technique usually does not extend to the Eddington limit. There are mild correlations among the AGN and host galaxy eigencoefficients, possibly indicating a link between recent star formation and the onset of AGN activity. The catalog of spectral reconstruction parameters is available as an electronic table.

  3. More Is Better: Selecting for Broad Host Range Bacteriophages.

    Science.gov (United States)

    Ross, Alexa; Ward, Samantha; Hyman, Paul

    2016-01-01

    Bacteriophages are viruses that infect bacteria. In this perspective, we discuss several aspects of a characteristic feature of bacteriophages, their host range. Each phage has its own particular host range, the range of bacteria that it can infect. While some phages can only infect one or a few bacterial strains, other phages can infect many species or even bacteria from different genera. Different methods for determining host range may give different results, reflecting the multiple mechanisms bacteria have to resist phage infection and reflecting the different steps of infection each method depends on. This makes defining host range difficult. Another difficulty in describing host range arises from the inconsistent use of the words "narrow" and especially "broad" when describing the breadth of the host range. Nearly all bacteriophages have been isolated using a single host strain of bacteria. While this procedure is fairly standard, it may more likely produce narrow rather than broad host range phage. Our results and those of others suggest that using multiple host strains during isolation can more reliably produce broader host range phages. This challenges the common belief that most bacteriophages have a narrow host range. We highlight the implications of this for several areas that are affected by host range including horizontal gene transfer and phage therapy. PMID:27660623

  4. More Is Better: Selecting for Broad Host Range Bacteriophages.

    Science.gov (United States)

    Ross, Alexa; Ward, Samantha; Hyman, Paul

    2016-01-01

    Bacteriophages are viruses that infect bacteria. In this perspective, we discuss several aspects of a characteristic feature of bacteriophages, their host range. Each phage has its own particular host range, the range of bacteria that it can infect. While some phages can only infect one or a few bacterial strains, other phages can infect many species or even bacteria from different genera. Different methods for determining host range may give different results, reflecting the multiple mechanisms bacteria have to resist phage infection and reflecting the different steps of infection each method depends on. This makes defining host range difficult. Another difficulty in describing host range arises from the inconsistent use of the words "narrow" and especially "broad" when describing the breadth of the host range. Nearly all bacteriophages have been isolated using a single host strain of bacteria. While this procedure is fairly standard, it may more likely produce narrow rather than broad host range phage. Our results and those of others suggest that using multiple host strains during isolation can more reliably produce broader host range phages. This challenges the common belief that most bacteriophages have a narrow host range. We highlight the implications of this for several areas that are affected by host range including horizontal gene transfer and phage therapy.

  5. More Is Better: Selecting for Broad Host Range Bacteriophages

    Science.gov (United States)

    Ross, Alexa; Ward, Samantha; Hyman, Paul

    2016-01-01

    Bacteriophages are viruses that infect bacteria. In this perspective, we discuss several aspects of a characteristic feature of bacteriophages, their host range. Each phage has its own particular host range, the range of bacteria that it can infect. While some phages can only infect one or a few bacterial strains, other phages can infect many species or even bacteria from different genera. Different methods for determining host range may give different results, reflecting the multiple mechanisms bacteria have to resist phage infection and reflecting the different steps of infection each method depends on. This makes defining host range difficult. Another difficulty in describing host range arises from the inconsistent use of the words “narrow” and especially “broad” when describing the breadth of the host range. Nearly all bacteriophages have been isolated using a single host strain of bacteria. While this procedure is fairly standard, it may more likely produce narrow rather than broad host range phage. Our results and those of others suggest that using multiple host strains during isolation can more reliably produce broader host range phages. This challenges the common belief that most bacteriophages have a narrow host range. We highlight the implications of this for several areas that are affected by host range including horizontal gene transfer and phage therapy. PMID:27660623

  6. The RepA_N replicons of Gram-positive bacteria: a family of broadly distributed but narrow host range plasmids.

    Science.gov (United States)

    Weaver, Keith E; Kwong, Stephen M; Firth, Neville; Francia, Maria Victoria

    2009-03-01

    The pheromone-responsive conjugative plasmids of Enterococcus faecalis and the multiresistance plasmids pSK1 and pSK41 of Staphylococcus aureus are among the best studied plasmids native to Gram-positive bacteria. Although these plasmids seem largely restricted to their native hosts, protein sequence comparison of their replication initiator proteins indicates that they are clearly related. Homology searches indicate that these replicons are representatives of a large family of plasmids and a few phage that are widespread among the low G+C Gram-positive bacteria. We propose to name this family the RepA_N family of replicons after the annotated conserved domain that the initiator protein contains. Detailed sequence comparisons indicate that the initiator protein phylogeny is largely congruent with that of the host, suggesting that the replicons have evolved along with their current hosts and that intergeneric transfer has been rare. However, related proteins were identified on chromosomal regions bearing characteristics indicative of ICE elements, and the phylogeny of these proteins displayed evidence of more frequent intergeneric transfer. Comparison of stability determinants associated with the RepA_N replicons suggests that they have a modular evolution as has been observed in other plasmid families.

  7. Adaptive Plasmid Evolution Results in Host-Range Expansion of a Broad-Host-Range Plasmid

    OpenAIRE

    De Gelder, Leen; Williams, Julia J.; Ponciano, José M; Sota, Masahiro; Eva M. Top

    2008-01-01

    Little is known about the range of hosts in which broad-host-range (BHR) plasmids can persist in the absence of selection for plasmid-encoded traits, and whether this “long-term host range” can evolve over time. Previously, the BHR multidrug resistance plasmid pB10 was shown to be highly unstable in Stenotrophomonas maltophilia P21 and Pseudomonas putida H2. To investigate whether this plasmid can adapt to such unfavorable hosts, we performed evolution experiments wherein pB10 was maintained ...

  8. Broad-Host-Range IncP-1 plasmids and their resistance potential

    Directory of Open Access Journals (Sweden)

    Magdalena ePopowska

    2013-03-01

    Full Text Available The plasmids of the incompatibility group IncP-1, also called IncP, as extrachromosomal genetic elements can transfer and replicate virtually in all Gram-negative bacteria. They are composed of backbone genes that encode a variety of essential functions and accessory genes that have implications for human health and environmental bioremediation. Broad-host-range IncP plasmids are known to spread genes between distinct phylogenetic groups of bacteria. These genes often code for resistances to a broad spectrum of antibiotics, heavy metals and quaternary ammonium compounds used as disinfectants. The backbone of these plasmids carries modules that enable them to effectively replicate, move to a new host via conjugative transfer and to be stably maintained in bacterial cells. The adaptive, resistance and virulence genes are mainly located on mobile genetic elements integrated between the functional plasmid backbone modules. Environmental studies have demonstrated the wide distribution of IncP-like replicons in manure, soils and wastewater treatment plants. They also are present in strains of pathogenic or opportunistic bacteria, which can be a cause for concern, because they may encode multiresistance. Their broad distribution suggests that IncP plasmids play a crucial role in bacterial adaptation by utilizing horizontal gene transfer. This review summarizes the variety of genetic information and physiological functions carried by IncP plasmids, which can contribute to the spread of antibiotic and heavy metal resistance while also mediating the process of bioremediation of pollutants. Due to the location of the resistance genes on plasmids with a broad host range and the presence of transposons carrying these genes it seems that the spread of these genes would be possible and quite hazardous in infection control. Future studies are required to determine the level of risk of the spread of resistance genes located on these plasmids.

  9. Permissiveness of soil microbial communities towards broad host range plasmids

    DEFF Research Database (Denmark)

    Klümper, Uli

    for plasmids carrying antibiotic resistance genes is increasingly suspected to majorly contribute to the emergence of multi-resistant pathogens. More specifically, I examined what fraction of a soil microbial community is permissive to plasmids, identified the phylogenetic identity of this fraction and studied......Horizontal transfer of mobile genetic elements facilitates adaptive and evolutionary processes in bacteria. Among the known mobile genetic elements, plasmids can confer their hosts with accessory adaptive traits, such as antibiotic or heavy metal resistances, or additional metabolic pathways....... Plasmids are implicated in the rapid spread of antibiotic resistance and the emergence of multi-resistant pathogenic bacteria, making it crucial to be able to quantify, understand, and, ideally, control plasmid transfer in mixed microbial communities. The fate of plasmids in microbial communities...

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

    KAUST Repository

    Emms, Madeleine

    2015-12-01

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

  11. New hepatitis B virus of cranes that has an unexpected broad host range.

    Science.gov (United States)

    Prassolov, Alexej; Hohenberg, Heinz; Kalinina, Tatyana; Schneider, Carola; Cova, Lucyna; Krone, Oliver; Frölich, Kai; Will, Hans; Sirma, Hüseyin

    2003-02-01

    All hepadnaviruses known so far have a very limited host range, restricted to their natural hosts and a few closely related species. This is thought to be due mainly to sequence divergence in the large envelope protein and species-specific differences in host components essential for virus propagation. Here we report an infection of cranes with a novel hepadnavirus, designated CHBV, that has an unexpectedly broad host range and is only distantly evolutionarily related to avihepadnaviruses of related hosts. Direct DNA sequencing of amplified CHBV DNA as well a sequencing of cloned viral genomes revealed that CHBV is most closely related to, although distinct from, Ross' goose hepatitis B virus (RGHBV) and slightly less closely related to duck hepatitis B virus (DHBV). Phylogenetically, cranes are very distant from geese and ducks and are most closely related to herons and storks. Naturally occurring hepadnaviruses in the last two species are highly divergent in sequence from RGHBV and DHBV and do not infect ducks or do so only marginally. In contrast, CHBV from crane sera and recombinant CHBV produced from LMH cells infected primary duck hepatocytes almost as efficiently as DHBV did. This is the first report of a rather broad host range of an avihepadnavirus. Our data imply either usage of similar or identical entry pathways and receptors by DHBV and CHBV, unusual host and virus adaptation mechanisms, or divergent evolution of the host genomes and cellular components required for virus propagation.

  12. Nucleotide Sequence and Characterization of the Broad-Host-Range Lactococcal Plasmid pWVO1

    NARCIS (Netherlands)

    Leenhouts, Cornelis; Tolner, Berend; Bron, Sierd; Kok, Jan; Venema, Gerhardus; Seegers, Jozef

    1991-01-01

    The nucleotide sequence of the Lactococcus lactis broad-host-range plasmid pWVO1, replicating in both gram-positive and gram-negative bacteria, was determined. This analysis revealed four open reading frames (ORFs). ORF A appeared to encode a trans-acting 26.8-kDa protein (RepA), necessary for repli

  13. Characterization of non-host resistance in broad bean to the wheat stripe rust pathogen

    Directory of Open Access Journals (Sweden)

    Cheng Yulin

    2012-06-01

    Full Text Available Abstract Background Non-host resistance (NHR confers plant species immunity against the majority of microbial pathogens and represents the most robust and durable form of plant resistance in nature. As one of the main genera of rust fungi with economic and biological importance, Puccinia infects almost all cereals but is unable to cause diseases on legumes. Little is known about the mechanism of this kind of effective defense in legumes to these non-host pathogens. Results In this study, the basis of NHR in broad bean (Vicia faba L. against the wheat stripe rust pathogen, Puccinia striiformis f. sp. tritici (Pst, was characterized. No visible symptoms were observed on broad bean leaves inoculated with Pst. Microscopic observations showed that successful location of stomata and haustoria formation were significantly reduced in Pst infection of broad bean. Attempted infection induced the formation of papillae, cell wall thickening, production of reactive oxygen species, callose deposition and accumulation of phenolic compounds in plant cell walls. The few Pst haustoria that did form in broad bean cells were encased in reactive oxygen and callose materials and those cells elicited cell death. Furthermore, a total of seven defense-related genes were identified and found to be up-regulated during the Pst infection. Conclusions The results indicate that NHR in broad bean against Pst results from a continuum of layered defenses, including basic incompatibility, structural and chemical strengthening of cell wall, posthaustorial hypersensitive response and induction of several defense-related genes, demonstrating the multi-layered feature of NHR. This work also provides useful information for further determination of resistance mechanisms in broad bean to rust fungi, especially the adapted important broad bean rust pathogen, Uromyces viciae-fabae, because of strong similarity and association between NHR of plants to unadapted pathogens and basal

  14. Transformation of Actinomyces spp. by a gram-negative broad-host-range plasmid.

    OpenAIRE

    Yeung, M K; Kozelsky, C S

    1994-01-01

    The gram-negative broad-host-range vector pJRD215 was transferred by electroporation into strains of Actinomyces viscosus or Actinomyces naeslundii at efficiencies which ranged from 10(2) to 10(7) transformants per microgram of plasmid DNA. The Actinomyces transformants expressed pJRD215-encoded resistance to kanamycin and streptomycin. Moreover, the transforming plasmid DNA had not undergone any deletions or rearrangements, nor had it integrated into the genomes of these strains.

  15. Broad host range plasmids can invade an unexpectedly diverse fraction of a soil bacterial community

    DEFF Research Database (Denmark)

    Klümper, Uli; Riber, Leise; Dechesne, Arnaud;

    2014-01-01

    Conjugal plasmids can provide microbes with full complements of new genes and constitute potent vehicles for horizontal gene transfer. Conjugal plasmid transfer is deemed responsible for the rapid spread of antibiotic resistance among microbes. While broad host range plasmids are known to transfer...... bacteria and can, therefore, directly connect large proportions of the soil bacterial gene pool. This finding reinforces the evolutionary and medical significances of these plasmids....

  16. Myxozoan infections of caecilians demonstrate broad host specificity and indicate a link with human activity.

    Science.gov (United States)

    Hartigan, Ashlie; Wilkinson, Mark; Gower, David J; Streicher, Jeffrey W; Holzer, Astrid S; Okamura, Beth

    2016-05-01

    Myxozoans are parasitic cnidarians that infect a wide variety of hosts. Vertebrates typically serve as intermediate hosts whereas definitive hosts are invertebrates, including annelids and bryozoans. Myxozoans are known to exploit species in two of the three extant amphibian orders (Anura: frogs and toads; Caudata: newts and salamanders). Here we use museum collections to determine, to our knowledge for the first time, whether myxozoans also exploit the third amphibian order (Gymnophiona: caecilians). Caecilians are a poorly known group of limbless amphibians, the ecologies of which range from aquatic to fully terrestrial. We examined 12 caecilian species in seven families (148 individuals total) characterised by a diversity of ecologies and life histories. Using morphological and molecular surveys, we discovered the presence of the myxozoan Cystodiscus axonis in two South American species (one of seven examined families) of aquatic caecilians - Typhlonectes natans and Typhlonectes compressicauda. All infected caecilians had been maintained in captivity in the United Kingdom prior to their preservation. Cystodiscus axonis is known from several Australian frog species and its presence in caecilians indicates a capacity for infecting highly divergent amphibian hosts. This first known report of myxozoan infections in caecilians provides evidence of a broad geographic and host range. However, the source of these infections remains unknown and could be related to exposure in South America, the U.K. or to conditions in captivity. PMID:26945641

  17. The broad spectrum of Trichinella hosts: from cold- to warm-blooded animals.

    Science.gov (United States)

    Pozio, E

    2005-09-01

    In recent years, studies on Trichinella have shown that the host range is wider than previously believed and new Trichinella species and genotypes have been described. Three classes of vertebrates are known to act as hosts, mammals, birds and reptiles, and infected vertebrates have been detected on all continents but Antarctica. Mammals represent the most important hosts and all Trichinella species are able to develop in this vertebrate class. Natural infections with Trichinella have been described in more than 150 mammalian species belonging to 12 orders (i.e., Marsupialia, Insectivora, Edentata, Chiroptera, Lagomorpha, Rodentia, Cetacea, Carnivora, Perissodactyla, Artiodactyla, Tylopoda and Primates). The epidemiology of the infection greatly varies by species relative to characteristics, such as diet, life span, distribution, behaviour, and relationships with humans. The non-encapsulated species Trichinella pseudospiralis, detected in both mammals (14 species) and birds (13 species), shows a cosmopolitan distribution with three distinguishable populations in the Palearctic, Nearctic and Australian regions. Two additional non-encapsulated species, Trichinella papuae, detected in wild pigs and saltwater crocodiles of Papua New Guinea, and Trichinella zimbabwensis, detected in farmed Nile crocodiles of Zimbabwe, can complete their life cycle in both mammals and reptiles. To the best of our knowledge, T. papuae and T. zimbabwensis are the only two parasites known to complete their entire life cycle independently of whether the host is warm-blooded or cold-blooded. This suggests that these two Trichinella species are capable of activating different physiological mechanisms, according to the specific vertebrate class hosting them. PMID:15970384

  18. Construction of the recombinant broad-host-range plasmids providing their bacterial hosts arsenic resistance and arsenite oxidation ability.

    Science.gov (United States)

    Drewniak, Lukasz; Ciezkowska, Martyna; Radlinska, Monika; Sklodowska, Aleksandra

    2015-02-20

    The plasmid pSinA of Sinorhizobium sp. M14 was used as a source of functional phenotypic modules, encoding proteins involved in arsenite oxidation and arsenic resistance, to obtain recombinant broad-host-range plasmids providing their bacterial hosts arsenic resistance and arsenite oxidative ability. An arsenite oxidation module was cloned into pBBR1MCS-2 vector yielding plasmid vector pAIO1, while an arsenic resistance module was cloned into pCM62 vector yielding plasmid pARS1. Both plasmid constructs were introduced (separately and together) into the cells of phylogenetically distant (representing Alpha-, Beta-, and Gammaproteobacteria) and physiologically diversified (unable to oxidize arsenite and susceptible/resistant to arsenite and arsenate) bacteria. Functional analysis of the modified strains showed that: (i) the plasmid pARS1 can be used for the construction of strains with an increased resistance to arsenite [up to 20mM of As(III), (ii) the presence of the plasmid pAIO1 in bacteria previously unable to oxidize As(III) to As(V), contributes to the acquisition of arsenite oxidation abilities by these cells, (iii) the highest arsenite utilization rate are observed in the culture of strains harbouring both the plasmids pAIO1 and pARS1, (iv) the strains harbouring the plasmid pAIO1 were able to grow on arsenic-contaminated mine waters (∼ 3.0 mg As L(-1)) without any supplementation. PMID:25617684

  19. Development of a gene silencing DNA vector derived from a broad host range geminivirus

    Directory of Open Access Journals (Sweden)

    Hancock Leandria C

    2009-07-01

    Full Text Available Abstract Background Gene silencing is proving to be a powerful tool for genetic, developmental, and physiological analyses. The use of viral induced gene silencing (VIGS offers advantages to transgenic approaches as it can be potentially applied to non-model systems for which transgenic techniques are not readily available. However, many VIGS vectors are derived from Gemini viruses that have limited host ranges. We present a new, unipartite vector that is derived from a curtovirus that has a broad host range and will be amenable to use in many non-model systems. Results The construction of a gene silencing vector derived from the geminivirus Beet curly top virus (BCTV, named pWSRi, is reported. Two versions of the vector have been developed to allow application by biolistic techniques or by agro-infiltration. We demonstrate its ability to silence nuclear genes including ribulose bisphosphate carboxylase small subunit (rbcS, transketolase, the sulfur allele of magnesium chelatase (ChlI, and two homeotic transcription factors in spinach or tomato by generating gene-specific knock-down phenotypes. Onset of phenotypes occurred 3 to 12 weeks post-inoculation, depending on the target gene, in organs that developed after the application. The vector lacks movement genes and we found no evidence for significant spread from the site of inoculation. However, viral amplification in inoculated tissue was detected and is necessary for systemic silencing, suggesting that signals generated from active viral replicons are efficiently transported within the plant. Conclusion The unique properties of the pWSRi vector, the ability to silence genes in meristem tissue, the separation of virus and silencing phenotypes, and the broad natural host range of BCTV, suggest that it will have wide utility.

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

    Science.gov (United States)

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

    2015-09-01

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

  1. Inhibition of influenza virus replication by targeting broad host cell pathways.

    Directory of Open Access Journals (Sweden)

    Isabelle Marois

    Full Text Available Antivirals that are currently used to treat influenza virus infections target components of the virus which can mutate rapidly. Consequently, there has been an increase in the number of resistant strains to one or many antivirals in recent years. Here we compared the antiviral effects of lysosomotropic alkalinizing agents (LAAs and calcium modulators (CMs, which interfere with crucial events in the influenza virus replication cycle, against avian, swine, and human viruses of different subtypes in MDCK cells. We observed that treatment with LAAs, CMs, or a combination of both, significantly inhibited viral replication. Moreover, the drugs were effective even when they were administered 8 h after infection. Finally, analysis of the expression of viral acidic polymerase (PA revealed that both drugs classes interfered with early events in the viral replication cycle. This study demonstrates that targeting broad host cellular pathways can be an efficient strategy to inhibit influenza replication. Furthermore, it provides an interesting avenue for drug development where resistance by the virus might be reduced since the virus is not targeted directly.

  2. METALLOCENE POLYETHYLENES WITH BROAD OR BIMODAL MOLECULAR WEIGHT DISTRIBUTION

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Seven new binuclear titanocenes with different linking bridges, unsubstituted or substituted on the Cp rings, were synthesized and tested for their effect on ethylene polymerization in the presence of MAO. The polyethylenes thus obtained had broad MWD or even bimodal GPC curves, as compared with that from two reference mononuclear titanocenes. This is explained by the difference in degree of steric hindrance around the active center sites imposed by the bulky substituted ligands assuming different configurations in the rotation of the catalyst molecules. Lower polymerization temperatures alleviate the effect of these configuration differences, as reflected in change in MW and -Mw/-Mn. This effect is not caused by decomposition or disproportionation of the binuclear titanocenes as evidenced by the stability of the catalyst.

  3. Two domains at the origin are required for replication and maintenance of broad-host-range plasmid R1162.

    OpenAIRE

    Kim, Y.J.; Lin, L. S.; Meyer, R. J.

    1987-01-01

    Two domains at the replicative origin of broad-host-range plasmid R1162 are required in cis for plasmid maintenance in Escherichia coli and for plasmid DNA replication in cell extracts. Increasing the distance between the domains reduces replication in vitro, without substantially changing plasmid DNA content or stability in vivo.

  4. Geographical Distribution of Phacellaria Benth.(Santalaceae)and its Hosts

    Institute of Scientific and Technical Information of China (English)

    Li Dognxue; Ding Yulong

    2006-01-01

    Based on the geographical distribution of the species of Phacellaria and its host plants in the world,we speculated on the possible time,sites,and migration of the origin of Phacellaria.The host plants of Phacellaria mainly belong to Loranthaceae.Plants of Phacellaria and their hosts are mainly distributed in tropical and subtropical areas.The plants of Phacellaria might have originated from a tropical area in the south of China before the Tertiary.Their ancestors were parasitic on the ancestors of some plants of Loranthaceae by chance during the Tertiary.It possibly took them millions of years to form a sturdy relationship with their hosts.

  5. The Black Hole-Bulge Relationship in Luminous Broad-Line Active Galactic Nuclei and Host Galaxies

    CERN Document Server

    Shen, J; Schneider, D P; Hall, P B

    2007-01-01

    We have measured the stellar velocity dispersions (\\sigma_*) and estimated the central black hole (BH) masses for over 900 broad-line active galactic nuclei (AGNs) observed with the Sloan Digital Sky Survey. The sample includes objects which have redshifts up to z=0.452, high quality spectra, and host galaxy spectra dominated by an early-type (bulge) component. The AGN and host galaxy spectral components were decomposed using an eigenspectrum technique. The BH masses (M_BH) were estimated from the AGN broad-line widths, and the velocity dispersions were measured from the stellar absorption spectra of the host galaxies. The range of black hole masses covered by the sample is approximately 10^6 < M_BH < 10^9 M_Sun. The host galaxy luminosity-velocity dispersion relationship follows the well-known Faber-Jackson relation for early-type galaxies, with a power-law slope 4.33+-0.21. The estimated BH masses are correlated with both the host luminosities (L_{H}) and the stellar velocity dispersions (\\sigma_*), s...

  6. Technologies to Increase PV Hosting Capacity in Distribution Feeders: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Fei; Mather, Barry; Gotseff, Peter

    2016-08-01

    This paper studies the distributed photovoltaic (PV) hosting capacity in distribution feeders by using the stochastic analysis approach. Multiple scenario simulations are conducted to analyze several factors that affect PV hosting capacity, including the existence of voltage regulator, PV location, the power factor of PV inverter and Volt/VAR control. Based on the conclusions obtained from simulation results, three approaches are then proposed to increase distributed PV hosting capacity, which can be formulated as the optimization problem to obtain the optimal solution. All technologies investigated in this paper utilize only existing assets in the feeder and therefore are implementable for a low cost. Additionally, the tool developed for these studies is described.

  7. Emerging trends in molecular interactions between plants and the broad host range fungal pathogens Botrytis cinerea and Sclerotinia sclerotiorum

    OpenAIRE

    Mbengue, Malick; Navaud, Olivier; Peyraud, Rémi; Barascud, Marielle; Badet, Thomas; Vincent, Rémy; Barbacci, Adelin; Raffaele, Sylvain

    2016-01-01

    Fungal plant pathogens are major threats to food security worldwide. Sclerotinia sclerotiorum and Botrytis cinerea are closely related Ascomycete plant pathogens causing mold diseases on hundreds of plant species. There is no genetic source of complete plant resistance to these broad host range pathogens known to date. Instead, natural plant populations show a continuum of resistance levels controlled by multiple genes, a phenotype designated as quantitative disease resistance. Little is know...

  8. Mapping of regions participating in replication, maintenance, and mobilization of the broad host range R plasmid pBS222

    International Nuclear Information System (INIS)

    As a result of analysis of the deletion derivatives, obtained in vitro by sodium bisulfite mutagenesis and cloned within the pUC19 vector regions of the broad host-range plasmid pBS222, genes participating in replication, maintenance, and mobilization of the plasmids have been mapped in a region with coordinates 0.2-2.5 kb and an area including the unique HindIII restriction site (12.3 kb). The derivatives pBS359, pBS361, and pBS362 belong to the smallest broad host-range plasmids. The authors have identified three polypeptides (molecular weights ∼ 15, 25, and 30 kdalton), two of which presumably participate in the provision of the broad host-range functions, and the other in the mobilization of plasmid pBS222. The possibility of molecular and genetic organization of plasmid pBS222 and the presence of recombination hot points and also the prospects of using this method for the preparation of vector derivatives are discussed

  9. Radio Through X-ray Spectral Energy Distributions of 38 Broad Absorption Line Quasars

    CERN Document Server

    Gallagher, S C; Brandt, W N; Egami, E; Hines, D C; Priddey, R S

    2007-01-01

    We have compiled the largest sample of multiwavelength spectral energy distributions (SEDs) of Broad Absorption Line (BAL) quasars to date, from the radio to the X-ray. We present new Spitzer MIPS (24, 70, and 160 micron) observations of 38 BAL quasars in addition to data from the literature and public archives. In general, the mid-infrared properties of BAL quasars are consistent with those of non-BAL quasars of comparable luminosity. In particular, the optical-to-mid-infrared luminosity ratios of the two populations are indistinguishable. We also measure or place upper limits on the contribution of star formation to the far-infrared power. Of 22 (57%) upper limits, seven quasars have sufficiently sensitive constraints to conclude that star formation likely contributes little (<20%) to their far-infrared power. The 17 BAL quasars (45%) with detected excess far-infrared emission likely host hyperluminous starbursts with L_fir,SF=10^{13-14} L_sun. Mid-infrared through X-ray composite BAL quasar SEDs are pre...

  10. The genome of Botrytis cinerea, a ubiquitous broad host range necrotroph

    NARCIS (Netherlands)

    Hahn, M.; Viaud, M.; Kan, van J.A.L.

    2014-01-01

    Botrytis cinerea is a necrotrophic ascomycete, causing serious pre- and postharvest crop losses worldwide on a wide variety of plant species. Considerable research in recent years has unraveled a variety of molecular tools that enables the fungus to invade host tissue, including the secretion of tox

  11. On the cosmic evolution of the scaling relations between black holes and their host galaxies: Broad Line AGN in the zCOSMOS survey

    CERN Document Server

    Merloni, A; Bolzonella, M; Brusa, M; Civano, F; Comastri, A; Elvis, M; Fiore, F; Gilli, R; Hao, H; Jahnke, K; Koekemoer, A M; Lusso, E; Mainieri, V; Mignoli, M; Miyaji, T; Renzini, A; Salvato, M; Silverman, Joseph; Trump, J; Vignali, C; Zamorani, G; Capak, P; Lilly, S J; Sanders, D; Taniguchi, Y; Bardelli, S; Carollo, C M; Caputi, K; Contini, T; Coppa, G; Cucciati, O; De la Torre, S; de Ravel, L; Franzetti, P; Garilli, B; Hasinger, G; Impey, C; Iovino, A; Iwasawa, K; Kampczyk, P; Kneib, J -P; Knobel, C; Kovac, K; Lamareille, F; Le Borgne, J F; Le Brun, V; Le Fèvre, O; Maier, C; Pellò, R; Peng, Y; Montero, E Perez; Ricciardelli, E; Scodeggio, M; Tanaka, M; Tasca, L A M; Tresse, L; Vergani, D; Zucca, E

    2009-01-01

    (Abriged) We report on the measurement of the rest frame K-band luminosity and total stellar mass of the hosts of 89 broad line Active Galactic Nuclei detected in the zCOSMOS survey in the redshift range 1host galaxy from that of the nuclear black hole in their Spectral Energy Distributions. We derive an estimate of black hole masses through the analysis of the broad Mg II emission lines observed in the medium-resolution spectra taken with VIMOS/VLT as part of the zCOSMOS project. We found that, as compared to the local value, the average black hole to host galaxy mass ratio appears to evolve positively with redshift, with a best fit evolution of the form (1+z)^{0.68 \\pm0.12 +0.6 -0.3}, where the large asymmetric systematic errors stem from the uncertainties in the choice of IMF, in the calibration of the virial relation used to estimate BH masses and in the mean QSO SED adopted. A thoroug...

  12. Characterization of JG024, a pseudomonas aeruginosa PB1-like broad host range phage under simulated infection conditions

    Directory of Open Access Journals (Sweden)

    Rohde Manfred

    2010-11-01

    Full Text Available Abstract Background Pseudomonas aeruginosa causes lung infections in patients suffering from the genetic disorder Cystic Fibrosis (CF. Once a chronic lung infection is established, P. aeruginosa cannot be eradicated by antibiotic treatment. Phage therapy is an alternative to treat these chronic P. aeruginosa infections. However, little is known about the factors which influence phage infection of P. aeruginosa under infection conditions and suitable broad host range phages. Results We isolated and characterized a phage, named JG024, which infects a broad range of clinical and environmental P. aeruginosa strains. Sequencing of the phage genome revealed that the phage JG024 is highly related to the ubiquitous and conserved PB1-like phages. The receptor of phage JG024 was determined as lipopolysaccharide. We used an artificial sputum medium to study phage infection under conditions similar to a chronic lung infection. Alginate production was identified as a factor reducing phage infectivity. Conclusions Phage JG024 is a suitable broad host range phage which could be used in phage therapy. Phage infection experiments under simulated chronic lung infection conditions showed that alginate production reduces phage infection efficiency.

  13. The korF region of broad-host-range plasmid RK2 encodes two polypeptides with transcriptional repressor activity.

    OpenAIRE

    Jagura-Burdzy, G; Ibbotson, J P; Thomas, C M

    1991-01-01

    Broad-host-range IncP plasmid RK2 possesses a series of operons involved in plasmid maintenance, whose expression is coordinated by a number of regulators, most of which are encoded in the central regulatory korA-korB operon. The nucleotide sequence of two new cistrons in this operon, comprising what we have previously designated the korF locus located between coordinates 57.0 and 56.0 kb on the genome of the IncP alpha plasmid RK2, is presented. The cistrons encode polypeptides of 173 and 17...

  14. Contribution of different segments of the par region to stable maintenance of the broad-host-range plasmid RK2.

    OpenAIRE

    Easter, C L; Sobecky, P A; Helinski, D. R.

    1997-01-01

    A 3.2-kb region of the broad-host-range plasmid RK2 has been shown to encode a highly efficient plasmid maintenance system that functions in a vector-independent manner. This region, designated par, consists of two divergently arranged operons: parCBA and parDE. The 0.7-kb parDE operon promotes plasmid stability by a postsegregational killing mechanism that ensures that plasmid-free daughter cells do not survive after cell division. The 2.3-kb parCBA operon encodes a site-specific resolvase p...

  15. Conjugative transfer of broad host range plasmids to an acidobacterial strain, Edaphobacter aggregans.

    Science.gov (United States)

    Bouhajja, Emna; Efthymiopoulos, Theocharis; George, Isabelle F; Moreels, David; Van Houdt, Rob; Mergeay, Max; Agathos, Spiros N

    2016-03-10

    The Acidobacteria phylum is of high ecological interest. Its members are ubiquitous and particularly abundant in soils but many are recalcitrant to cultivation in the laboratory. Thus, the ability of Acidobacteria to capture and maintain plasmids remains largely unexplored. In this work we tested the transfer and the stability of (i) the PromA plasmid pMOL98 and (ii) the IncQ plasmid pKT230 to the acidobacterial strain Edaphobacter aggregans DSM 19364. To this end quantitative conjugation assays were performed and transconjugants were scored for plasmid-borne antibiotic selection markers. The tested plasmids were transferred and maintained in the new host. Plasmid pMOL98 was more stable than pKT230 in Ed. aggregans in the absence of positive selection. Thus, from an ecological point of view, we have extended the host range of PromA and IncQ plasmids for the first time to an acidobacterial strain. Furthermore, we have uncovered the potential of Acidobacteria to capture as-yet-unknown plasmids and to foster the development of new cloning and expression systems for the exploitation of biotechnologically valuable soil resources. PMID:26808872

  16. Novel broad host range shuttle vectors for expression in Escherichia coli, Bacillus subtilis and Pseudomonas putida.

    Science.gov (United States)

    Troeschel, Sonja Christina; Thies, Stephan; Link, Olga; Real, Catherine Isabell; Knops, Katja; Wilhelm, Susanne; Rosenau, Frank; Jaeger, Karl-Erich

    2012-10-15

    Novel shuttle vectors named pEBP were constructed to allow the gene expression in different bacterial hosts including Escherichia coli, Bacillus subtilis and Pseudomonas putida. These vectors share the inducible promoters P(T7) and P(Xyl) and a cos site to enable packaging of plasmid DNA into phage, and carry different multiple cloning sites and antibiotic resistance genes. Vector pEBP41 generally replicates episomally while pEBP18 replicates episomally in Gram-negative bacteria only, but integrates into the chromosome of B. subtilis. Plasmid copy numbers determined for E. coli and P. putida were in the range of 5-50 per cell. The functionality of pEBP18 and pEBP41 was confirmed by expression of two lipolytic enzymes, namely lipase A from B. subtilis and cutinase from the eukaryotic fungus Fusarium solani pisi in three different host strains. Additionally, we report here the construction of a T7 RNA polymerase-based expression strain of P. putida. PMID:22440389

  17. The landscape of host transcriptional response programs commonly perturbed by bacterial pathogens: towards host-oriented broad-spectrum drug targets.

    Directory of Open Access Journals (Sweden)

    Yared H Kidane

    Full Text Available BACKGROUND: The emergence of drug-resistant pathogen strains and new infectious agents pose major challenges to public health. A promising approach to combat these problems is to target the host's genes or proteins, especially to discover targets that are effective against multiple pathogens, i.e., host-oriented broad-spectrum (HOBS drug targets. An important first step in the discovery of such drug targets is the identification of host responses that are commonly perturbed by multiple pathogens. RESULTS: In this paper, we present a methodology to identify common host responses elicited by multiple pathogens. First, we identified host responses perturbed by each pathogen using a gene set enrichment analysis of publicly available genome-wide transcriptional datasets. Then, we used biclustering to identify groups of host pathways and biological processes that were perturbed only by a subset of the analyzed pathogens. Finally, we tested the enrichment of each bicluster in human genes that are known drug targets, on the basis of which we elicited putative HOBS targets for specific groups of bacterial pathogens. We identified 84 up-regulated and three down-regulated statistically significant biclusters. Each bicluster contained a group of pathogens that commonly dysregulated a group of biological processes. We validated our approach by checking whether these biclusters correspond to known hallmarks of bacterial infection. Indeed, these biclusters contained biological process such as inflammation, activation of dendritic cells, pro- and anti- apoptotic responses and other innate immune responses. Next, we identified biclusters containing pathogens that infected the same tissue. After a literature-based analysis of the drug targets contained in these biclusters, we suggested new uses of the drugs Anakinra, Etanercept, and Infliximab for gastrointestinal pathogens Yersinia enterocolitica, Helicobacter pylori kx2 strain, and enterohemorrhagic Escherichia

  18. Emerging trends in molecular interactions between plants and the broad host range fungal pathogens Botrytis cinerea and Sclerotinia sclerotiorum

    Directory of Open Access Journals (Sweden)

    Malick eMbengue

    2016-03-01

    Full Text Available Fungal plant pathogens are major threats to food security worldwide. Sclerotinia sclerotiorum and Botrytis cinerea are closely related Ascomycete plant pathogens causing mold diseases on hundreds of plant species. There is no genetic source of complete plant resistance to these broad host range pathogens known to date. Instead, natural plant populations show a continuum of resistance levels controlled by multiple genes, a phenotype designated as quantitative disease resistance. Little is known about the molecular mechanisms controlling the interaction between plants and S. sclerotiorum and B. cinerea but significant advances were made on this topic in the last years. This minireview highlights a selection of nine themes that emerged in recent research reports on the molecular bases of plant-S. sclerotiorum and plant-B. cinerea interactions. On the fungal side, this includes progress on understanding the role of oxalic acid, on the study of fungal small secreted proteins. Next, we discuss the exchanges of small RNA between organisms and the control of cell death in plant and fungi during pathogenic interactions. Finally on the plant side, we highlight defense priming by mechanical signals, the characterization of plant Receptor-like proteins and the hormone abscisic acid in the response to B. cinerea and S. sclerotiorum , the role of plant general transcription machinery and plant small bioactive peptides. These represent nine trends we selected as remarkable in our understanding of fungal molecules causing disease and plant mechanisms associated with disease resistance to two devastating broad host range fungi.

  19. Emerging Trends in Molecular Interactions between Plants and the Broad Host Range Fungal Pathogens Botrytis cinerea and Sclerotinia sclerotiorum.

    Science.gov (United States)

    Mbengue, Malick; Navaud, Olivier; Peyraud, Rémi; Barascud, Marielle; Badet, Thomas; Vincent, Rémy; Barbacci, Adelin; Raffaele, Sylvain

    2016-01-01

    Fungal plant pathogens are major threats to food security worldwide. Sclerotinia sclerotiorum and Botrytis cinerea are closely related Ascomycete plant pathogens causing mold diseases on hundreds of plant species. There is no genetic source of complete plant resistance to these broad host range pathogens known to date. Instead, natural plant populations show a continuum of resistance levels controlled by multiple genes, a phenotype designated as quantitative disease resistance. Little is known about the molecular mechanisms controlling the interaction between plants and S. sclerotiorum and B. cinerea but significant advances were made on this topic in the last years. This minireview highlights a selection of nine themes that emerged in recent research reports on the molecular bases of plant-S. sclerotiorum and plant-B. cinerea interactions. On the fungal side, this includes progress on understanding the role of oxalic acid, on the study of fungal small secreted proteins. Next, we discuss the exchanges of small RNA between organisms and the control of cell death in plant and fungi during pathogenic interactions. Finally on the plant side, we highlight defense priming by mechanical signals, the characterization of plant Receptor-like proteins and the hormone abscisic acid in the response to B. cinerea and S. sclerotiorum, the role of plant general transcription machinery and plant small bioactive peptides. These represent nine trends we selected as remarkable in our understanding of fungal molecules causing disease and plant mechanisms associated with disease resistance to two devastating broad host range fungi. PMID:27066056

  20. Identification and characterization of the host protein DNAJC14 as a broadly active flavivirus replication modulator.

    Directory of Open Access Journals (Sweden)

    Zhigang Yi

    Full Text Available Viruses in the Flavivirus genus of the Flaviviridae family are arthropod-transmitted and contribute to staggering numbers of human infections and significant deaths annually across the globe. To identify cellular factors with antiviral activity against flaviviruses, we screened a cDNA library using an iterative approach. We identified a mammalian Hsp40 chaperone protein (DNAJC14 that when overexpressed was able to mediate protection from yellow fever virus (YFV-induced cell death. Further studies revealed that DNAJC14 inhibits YFV at the step of viral RNA replication. Since replication of bovine viral diarrhea virus (BVDV, a member of the related Pestivirus genus, is also known to be modulated by DNAJC14, we tested the effect of this host factor on diverse Flaviviridae family members. Flaviviruses, including the pathogenic Asibi strain of YFV, Kunjin, and tick-borne Langat virus, as well as a Hepacivirus, hepatitis C virus (HCV, all were inhibited by overexpression of DNAJC14. Mutagenesis showed that both the J-domain and the C-terminal domain, which mediates self-interaction, are required for anti-YFV activity. We found that DNAJC14 does not block YFV nor HCV NS2-3 cleavage, and using non-inhibitory mutants demonstrate that DNAJC14 is recruited to YFV replication complexes. Immunofluorescence analysis demonstrated that endogenous DNAJC14 rearranges during infection and is found in replication complexes identified by dsRNA staining. Interestingly, silencing of endogenous DNAJC14 results in impaired YFV replication suggesting a requirement for DNAJC14 in YFV replication complex assembly. Finally, the antiviral activity of overexpressed DNAJC14 occurs in a time- and dose-dependent manner. DNAJC14 overexpression may disrupt the proper stoichiometry resulting in inhibition, which can be overcome upon restoration of the optimal ratios due to the accumulation of viral nonstructural proteins. Our findings, together with previously published work

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

    Science.gov (United States)

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

    2013-01-01

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

  2. A Nonparametric Shewhart-Type Quality Control Chart for Monitoring Broad Changes in a Process Distribution

    Directory of Open Access Journals (Sweden)

    Saad T. Bakir

    2012-01-01

    Full Text Available This paper develops a distribution-free (or nonparametric Shewhart-type statistical quality control chart for detecting a broad change in the probability distribution of a process. The proposed chart is designed for grouped observations, and it requires the availability of a reference (or training sample of observations taken when the process was operating in-control. The charting statistic is a modified version of the two-sample Kolmogorov-Smirnov test statistic that allows the exact calculation of the conditional average run length using the binomial distribution. Unlike the traditional distribution-based control charts (such as the Shewhart X-Bar, the proposed chart maintains the same control limits and the in-control average run length over the class of all (symmetric or asymmetric continuous probability distributions. The proposed chart aims at monitoring a broad, rather than a one-parameter, change in a process distribution. Simulation studies show that the chart is more robust against increased skewness and/or outliers in the process output. Further, the proposed chart is shown to be more efficient than the Shewhart X-Bar chart when the underlying process distribution has tails heavier than those of the normal distribution.

  3. Broad host range plasmid-based gene transfer system in the cyanobacterium Gloeobacter violaceus which lacks thylakoids

    Institute of Scientific and Technical Information of China (English)

    GUO Haitao; XU Xudong

    2004-01-01

    Gloeobacter violaceus, a cyanobacterium lack of thylakoids, is refractory to genetic manipulations because its cells are enveloped by a thick gelatinous sheath and in colonial form.In this study, a large number of single cells were obtained by repeated pumping with a syringe with the gelatinous sheath removed.And an exogenous broad host range plasmid pKT210 was conjugatively transferred into G.violaceus.Analyses with dot-blot hybridization and restriction mapping showed that the exogenous plasmid pKT210 had been introduced into G.violaceus and stably maintained with no alteration in its structure.pKT210 extracted from G.violaceus exconjugants could be transformed into the mcr- mrr- E.coli strain DH10B but not the mcr+ mrr+ strain DH5α, which suggests that a methylase system may be present in G.violaceus.

  4. Transformation of Azotobacter vinelandii OP with a broad host range plasmid containing a cloned chromosomal nif-DNA marker.

    Science.gov (United States)

    Bingle, W H

    1988-05-01

    The non-nitrogen-fixing (Nif-) strain UW10 of Azotobacter vinelandii OP (UW) was naturally induced to competence and transformed with broad host range plasmid pKT210 containing the cloned wild-type nif-10 locus from A. vinelandii UW (Nif+); this marker was unable to complement the nif-10 mutation in trans, but could through recombination with the chromosome. The most frequent type of transformation event observed was recombination between the homologous regions of the plasmid and chromosome (producing Nif+ transformants) with loss of the plasmid vector. At a substantially lower frequency, transformants expressing the plasmid-encoded antibiotic resistance determinants were isolated which were phenotypically Nif-. Agarose gel electrophoresis showed that these transformants contained a plasmid migrating with the same mobility as the original donor plasmid. During culture these transformants acquired a Nif+ phenotype without the loss of the plasmid, as judged by the use of a hybridization probe specific for the cloned nif-DNA fragment. These data indicate that plasmids carrying sequences homologous to chromosomal sequences could be maintained in recombination-proficient A. vinelandii UW. The introduction of plasmids containing sequences homologous to chromosomal sequences was facilitated by prelinearization of the plasmid using a restriction endonuclease generating cohesive ends. Because the site of linearization could be chosen outside the region of shared homology, it was unlikely that the route of plasmid establishment occurred via a homology-facilitated transformation mechanism. The data also indicated that A. vinelandii UW could harbor broad host range cloning vectors based on plasmid RSF1010 without significant impairment of its nitrogen-fixation ability.

  5. SN 2010ay Is a Luminous and Broad-Lined Type Ic Supernova Within a Low-Metallicity Host Galaxy

    Science.gov (United States)

    Sanders, N. E.; Soderberg, A. M.; Valenti, S.; Foley, R. J.; Chornock, R.; Chomiuk, L.; Berger, E.; Smartt, S.; Hurley, K.; Barthelmy, S. D.; Levesque, E. M.; Narayan, G.; Botticella, M. T.; Briggs, M. S.; Connaughton, V.; Terada, Y.; Gehrels, N.; Golenetskii, S.; Mazets, E.; Cline, T.; von Kienlin, A.; Boynton, W.; Chambers, K. C.; Grav, T.; Heasley, J. N.

    2012-01-01

    We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3pi survey just approximately 4 days after explosion. The supernova (SN) had a peak luminosity, MR approx. -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v Si (is) approx. 19×10(exp 3) km s-1 at approximately 40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs. Moreover, the velocity declines approximately 2 times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of 56Ni, MNi = 0.9 solar mass. Applying scaling relations to the light curve, we estimate a total ejecta mass, Mej (is) approx. 4.7 solar mass, and total kinetic energy, EK (is) approx. 11 × 10(exp 51) erg. The ratio of MNi to Mej is approximately 2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log(O/H)PP04 + 12 = 8.19) of the explosion site within the host galaxy places SN 2010ay in the low-metallicity regime populated by GRB-SNe, and (is) approximately 0.5(0.2) dex lower than that typically measured for the host environments of normal (broad-lined) SNe Ic. We constrain any gamma-ray emission with E(gamma) (is) approximately less than 6 × 10(exp 48) erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E (is) approximately greater than 10(exp 48) erg. We therefore rule out the association of a relativistic outflow like those that accompanied SN 1998bw and traditional long-duration gamma-ray bursts (GRBs), but we place less-stringent constraints on a weak afterglow like that seen from XRF

  6. Distribution of Borrelia burgdorferi in host mice in Pennsylvania.

    OpenAIRE

    Lord, R D; Lord, V R; Humphreys, J. G.; McLean, R G

    1994-01-01

    Host mice (Peromyscus leucopus and Peromyscus maniculatus) were sampled throughout the state of Pennsylvania to determine the geographical and ecological distribution of the Lyme disease spirochete Borrelia burgdorferi. All 67 counties of the state were sampled. A total of 1,619 mice were captured from a total of 157 sites during the period 1990 to 1993 for an overall capture rate of 29.69%. A total of 112 (6.92%) isolations of B. burgdorferi were made. The distribution of isolations revealed...

  7. Radiation Pressure Confinement -- III. The origin of the broad ionization distribution in AGN outflows

    CERN Document Server

    Stern, Jonathan; Laor, Ari; Baskin, Alexei; Holczer, Tomer

    2014-01-01

    The winds of ionized gas driven by Active Galactic Nuclei (AGN) can be studied through absorption features in their X-ray spectra. A recurring feature of these outflows is their broad ionization distribution, including essentially all ionization levels (e.g., Fe^0+ to Fe^25+). The absorption measure distribution (AMD) is defined as the distribution of column density with ionization parameter |dN / dlog xi|. The AMD extends over a wide range of 0.1 < xi < 10^4 (cgs), and is remarkably similar in different objects. Power-law fits to the observed AMDs (|dN / dlog xi| ~ N_1 xi^a) yield N_1 = 3x10^21 cm^-2 +- 0.4 dex and a = 0 -- 0.4. What is the source of this broad ionization distribution, and what sets the small range of observed $N_1$ and $a$ values? A common interpretation is a multiphase outflow, with a wide range of gas densities in a uniform pressure medium. However, it has already been shown that the incident radiation pressure leads to a gas pressure gradient in the photoionized gas, and therefore ...

  8. Modeling of the lithium-air battery cathodes with broad pore size distribution

    Science.gov (United States)

    Sergeev, Artem V.; Chertovich, Alexander V.; Itkis, Daniil M.

    2016-09-01

    Achieving theoretical promises of 1000 W h/kg specific energy for lithium-air batteries is quite challenging due to limited transport in the cathode along with electrode passivation. Transport can be enhanced in the electrodes with complex hierarchical pore architecture. Here, using computer simulations we analyze the effects of cathode pore size distribution (PSD) on capacity and discharge curve shape. Calculations considering a broad PSD revealed that even small discharge product resistivity prevents larger pores from accumulating the discharge product and thus turning them into non-clogging oxygen supply channels. Thus optimization of cathode architecture by adding of large-scale cavities enables cell capacity enhancement.

  9. Distributions of Quasar Hosts on the Galaxy Main Sequence Plane

    Science.gov (United States)

    Zhang, Zhoujian; Shi, Yong; Rieke, George H.; Xia, Xiaoyang; Wang, Yikang; Sun, Bingqing; Wan, Linfeng

    2016-03-01

    The relation between star formation rates (SFRs) and stellar masses, i.e., the galaxy main sequence, is a useful diagnostic of galaxy evolution. We present the distributions relative to the main sequence of 55 optically selected PG and 12 near-IR-selected Two Micron All Sky Survey (2MASS) quasars at z ≤ 0.5. We estimate the quasar host stellar masses from Hubble Space Telescope or ground-based AO photometry, and the SFRs through the mid-infrared aromatic features and far-IR photometry. We find that PG quasar hosts more or less follow the main sequence defined by normal star-forming galaxies while 2MASS quasar hosts lie systematically above the main sequence. PG and 2MASS quasars with higher nuclear luminosities seem to have higher specific SFRs (sSFRs), although there is a large scatter. No trends are seen between sSFRs and SMBH masses, Eddington ratios, or even morphology types (ellipticals, spirals, and mergers). Our results could be placed in an evolutionary scenario with quasars emerging during the transition from ULIRGs/mergers to ellipticals. However, combined with results at higher redshift, they suggest that quasars can be widely triggered in normal galaxies as long as they contain abundant gas and have ongoing star formation.

  10. Comparative analysis of Chlamydia psittaci genomes reveals the recent emergence of a pathogenic lineage with a broad host range.

    Science.gov (United States)

    Read, Timothy D; Joseph, Sandeep J; Didelot, Xavier; Liang, Brooke; Patel, Lisa; Dean, Deborah

    2013-01-01

    Chlamydia psittaci is an obligate intracellular bacterium. Interest in Chlamydia stems from its high degree of virulence as an intestinal and pulmonary pathogen across a broad range of animals, including humans. C. psittaci human pulmonary infections, referred to as psittacosis, can be life-threatening, which is why the organism was developed as a bioweapon in the 20th century and is listed as a CDC biothreat agent. One remarkable recent result from comparative genomics is the finding of frequent homologous recombination across the genome of the sexually transmitted and trachoma pathogen Chlamydia trachomatis. We sought to determine if similar evolutionary dynamics occurred in C. psittaci. We analyzed 20 C. psittaci genomes from diverse strains representing the nine known serotypes of the organism as well as infections in a range of birds and mammals, including humans. Genome annotation revealed a core genome in all strains of 911 genes. Our analyses showed that C. psittaci has a history of frequently switching hosts and undergoing recombination more often than C. trachomatis. Evolutionary history reconstructions showed genome-wide homologous recombination and evidence of whole-plasmid exchange. Tracking the origins of recombinant segments revealed that some strains have imported DNA from as-yet-unsampled or -unsequenced C. psittaci lineages or other Chlamydiaceae species. Three ancestral populations of C. psittaci were predicted, explaining the current population structure. Molecular clock analysis found that certain strains are part of a clonal epidemic expansion likely introduced into North America by South American bird traders, suggesting that psittacosis is a recently emerged disease originating in New World parrots. PMID:23532978

  11. Broad host range ProUSER vectors enable fast characterization of inducible promoters and optimization of p-coumaric acid production in Pseudomonas putida KT2440

    DEFF Research Database (Denmark)

    Calero Valdayo, Patricia; Ingemann Jensen, Sheila; Nielsen, Alex Toftgaard

    2016-01-01

    Pseudomonas putida KT2440 has gained increasing interest as a host for the production of biochemicals. Because of the lack of a systematic characterization of inducible promoters in this strain, we generated ProUSER broad-host-expression plasmids that facilitate fast uracil-based cloning. A set...... of ProUSER-reporter vectors was further created to characterize different inducible promoters. The PrhaB and Pm promoters were orthogonal and showed titratable, high, and homogeneous expression. To optimize the production of p-coumaric acid, P. putida was engineered to prevent degradation of tyrosine...... achieved in Pseudomonads under comparable conditions. With broad-host-range compatibility, the ProUSER vectors will serve as useful tools for optimizing gene expression in a variety of bacteria....

  12. Distributed generation hosting capacity calculation of MV distribution feeders in Turkey

    DEFF Research Database (Denmark)

    Altin, Müfit; Oguz, Emre Utku; Bizkevelci, Erdal;

    2014-01-01

    Integration of distributed generation into distribution networks introduces new challenges to distribution system operators while the penetration level increases. One of the challenges is the voltage rise issue as a part of the steady-state analysis of DGs during planning and operational stages....... This issue should be analyzed in order to determine the hosting capacity of distribution feeders in the first instance. Accordingly, Turkey is a promising candidate to integrate high penetration of DGs and has recently started to publish regulations for DGs. This paper presents a method to calculate DG...

  13. Supercube grains leading to a strong cube texture and a broad grain size distribution after recrystallization

    Science.gov (United States)

    Lin, F. X.; Zhang, Y. B.; Pantleon, W.; Jensen, D. Juul

    2015-08-01

    This work revisits the classical subject of recrystallization of cold-rolled copper. Two characterization techniques are combined: three-dimensional X-ray diffraction using synchrotron X-rays, which is used to measure the growth kinetics of individual grains in situ, and electron backscatter diffraction, which is used for statistical analysis of the microstructural evolution. As the most striking result, the strong cube texture after recrystallization is found to be related to a few super large cube grains, which were named supercube grains. These few supercube grains become large due to higher growth rates. However, most other cube grains do not grow preferentially. Because of the few supercube grains, the grain size distribution after recrystallization is broad. Reasons for the higher growth rates of supercube grains are discussed, and are related to the local deformed microstructure.

  14. Supercube grains leading to a strong cube texture and a broad grain size distribution after recrystallization

    DEFF Research Database (Denmark)

    Lin, F.X.; Zhang, Y. B.; Pantleon, W.;

    2015-01-01

    diffraction, which is used for statistical analysis of the microstructural evolution. As the most striking result, the strong cube texture after recrystallization is found to be related to a few super large cube grains, which were named supercube grains. These few supercube grains become large due to higher......This work revisits the classical subject of recrystallization of cold-rolled copper. Two characterization techniques are combined: three-dimensional X-ray diffraction using synchrotron X-rays, which is used to measure the growth kinetics of individual grains in situ, and electron backscatter...... growth rates. However, most other cube grains do not grow preferentially. Because of the few supercube grains, the grain size distribution after recrystallization is broad. Reasons for the higher growth rates of supercube grains are discussed, and are related to the local deformed microstructure....

  15. Rapid and broad wavelength sweeping of standard telecommunication distributed feedback laser diode.

    Science.gov (United States)

    Njegovec, Matej; Donlagic, Denis

    2013-06-01

    This Letter presents a method for the fast and broad wavelength sweeping of a standard setup of a diode's active region and its immediate vicinity, which contain the diode's optical feedback system. The selective and rapid heating of the active region is possible due to the confinement of the voltage drop to the active diode's region that has submicrometer thickness. Using the presented method and an off-the-shelf telecommunication distributed feedback laser diode, we demonstrate wavelength sweeps in excess of 10 nm that were completed in about 200 ns, while generating average optical power in excess of 50 mW. In spite of high-amplitude current-drive pulses, 6000 h continuous operation of the diode within such an operational regime did not show any significant degradation of the diode's performance.

  16. The distribution of weaver ant pheromones on host trees

    DEFF Research Database (Denmark)

    Offenberg, Joachim

    2007-01-01

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

  17. High heritability is compatible with the broad distribution of set point viral load in HIV carriers.

    Directory of Open Access Journals (Sweden)

    Sebastian Bonhoeffer

    2015-02-01

    Full Text Available Set point viral load in HIV patients ranges over several orders of magnitude and is a key determinant of disease progression in HIV. A number of recent studies have reported high heritability of set point viral load implying that viral genetic factors contribute substantially to the overall variation in viral load. The high heritability is surprising given the diversity of host factors associated with controlling viral infection. Here we develop an analytical model that describes the temporal changes of the distribution of set point viral load as a function of heritability. This model shows that high heritability is the most parsimonious explanation for the observed variance of set point viral load. Our results thus not only reinforce the credibility of previous estimates of heritability but also shed new light onto mechanisms of viral pathogenesis.

  18. Co-gradient variation in growth rate and development time of a broadly distributed butterfly.

    Directory of Open Access Journals (Sweden)

    Madeleine Barton

    Full Text Available Widespread species often show geographic variation in thermally-sensitive traits, providing insight into how species respond to shifts in temperature through time. Such patterns may arise from phenotypic plasticity, genetic adaptation, or their interaction. In some cases, the effects of genotype and temperature may act together to reduce, or to exacerbate, phenotypic variation in fitness-related traits across varying thermal environments. We find evidence for such interactions in life-history traits of Heteronympha merope, a butterfly distributed across a broad latitudinal gradient in south-eastern Australia. We show that body size in this butterfly is negatively related to developmental temperature in the laboratory, in accordance with the temperature-size rule, but not in the field, despite very strong temperature gradients. A common garden experiment on larval thermal responses, spanning the environmental extremes of H. merope's distribution, revealed that butterflies from low latitude (warmer climate populations have relatively fast intrinsic growth and development rates compared to those from cooler climates. These synergistic effects of genotype and temperature across the landscape (co-gradient variation are likely to accentuate phenotypic variation in these traits, and this interaction must be accounted for when predicting how H. merope will respond to temperature change through time. These results highlight the importance of understanding how variation in life-history traits may arise in response to environmental change. Without this knowledge, we may fail to detect whether organisms are tracking environmental change, and if they are, whether it is by plasticity, adaptation or both.

  19. Temperature governs on-host distribution of the northern fowl mite, Ornithonyssus sylviarum (Acari: Macronyssidae).

    Science.gov (United States)

    De La Riva, Deborah G; Soto, Diane; Mullens, Bradley A

    2015-02-01

    The northern fowl mite, Ornithonyssus sylviarum (Canestri & Fanzago), is an ectoparasite of more than 70 species of North American wild birds, but it has a particularly significant impact on chickens, where it is a permanent resident of vent feathers. Improved control practices depend on a better understanding of host-mite relationships. ISA Brown hens were inoculated experimentally with northern fowl mite adults, and northern fowl mite populations developed naturally. Using a fast-response microprobe, temperatures of individual vent feathers (n = 15) were recorded at 5-mm increments along the length of the feather shaft. Immediately after temperatures were recorded, the individual feathers were quickly clipped at the skin surface and then flash-frozen between 2 small blocks of dry ice, freezing all northern fowl mite stages in situ. The feathers then were cut into 5-mm sections for careful mite enumeration by life stage. There were no overall differences among life stages in the distributions on the feather. Mite positions on feathers (distance from skin) varied distinctly with feather zone temperatures, as well as with ambient and average temperatures over the prior 24 hr. Ambient temperature at time of sampling affected the positions of the 2 mobile categories, adults and larvae/nymphs, but showed no statistical relationship with egg distribution. In contrast, ambient 24-hr temperature influenced the positions of all life stages. On-host feather temperatures reflected ambient temperatures. Feathers collected on hot days (ambient temperatures of 23-33 C) provided a narrow and quite warm range of temperature conditions for mites (often >30-36 C). Temperatures on cool days (ambient temperatures of <23 C) provided much wider on-host temperature ranges for mites to occupy (13-35 C). Mites were farther from the skin on warmer days. When mites had a broad range of temperatures, the feather temperature zone occupied by all life stages averaged 28-29 C. Mites move to

  20. Comparative Analysis of Chlamydia psittaci Genomes Reveals the Recent Emergence of a Pathogenic Lineage with a Broad Host Range

    OpenAIRE

    Read, Timothy D.; Joseph, Sandeep J; Didelot, Xavier; Liang, Brooke; Patel, Lisa; Dean, Deborah

    2013-01-01

    ABSTRACT Chlamydia psittaci is an obligate intracellular bacterium. Interest in Chlamydia stems from its high degree of virulence as an intestinal and pulmonary pathogen across a broad range of animals, including humans. C. psittaci human pulmonary infections, referred to as psittacosis, can be life-threatening, which is why the organism was developed as a bioweapon in the 20th century and is listed as a CDC biothreat agent. One remarkable recent result from comparative genomics is the findin...

  1. The broad-spectrum antiviral compound ST-669 restricts chlamydial inclusion development and bacterial growth and localizes to host cell lipid droplets within treated cells.

    Science.gov (United States)

    Sandoz, Kelsi M; Valiant, William G; Eriksen, Steven G; Hruby, Dennis E; Allen, Robert D; Rockey, Daniel D

    2014-07-01

    Novel broad-spectrum antimicrobials are a critical component of a strategy for combating antibiotic-resistant pathogens. In this study, we explored the activity of the broad-spectrum antiviral compound ST-669 for activity against different intracellular bacteria and began a characterization of its mechanism of antimicrobial action. ST-669 inhibits the growth of three different species of chlamydia and the intracellular bacterium Coxiella burnetii in Vero and HeLa cells but not in McCoy (murine) cells. The antichlamydial and anti-C. burnetii activity spectrum was consistent with those observed for tested viruses, suggesting a common mechanism of action. Cycloheximide treatment in the presence of ST-669 abrogated the inhibitory effect, demonstrating that eukaryotic protein synthesis is required for tested activity. Immunofluorescence microscopy demonstrated that different chlamydiae grow atypically in the presence of ST-669, in a manner that suggests the compound affects inclusion formation and organization. Microscopic analysis of cells treated with a fluorescent derivative of ST-669 demonstrated that the compound localized to host cell lipid droplets but not to other organelles or the host cytosol. These results demonstrate that ST-669 affects intracellular growth in a host-cell-dependent manner and interrupts proper development of chlamydial inclusions, possibly through a lipid droplet-dependent process. PMID:24777097

  2. SN 2010ay is a Luminous and Broad-lined Type Ic Supernova within a Low-metallicity Host Galaxy

    CERN Document Server

    Sanders, Nathan E; Valenti, S; Chomiuk, L; Berger, E; Smartt, S; Hurley, K; Barthelmy, S D; Chornock, R; Foley, R J; Levesque, E M; Narayan, G; Kirshner, R P; Botticella, M T; Briggs, M S; Connaughton, V; Terada, Y; Gehrels, N; Golenetskii, S; Mazets, E; Cline, T; von Kienlin, A; Boynton, W; Chambers, K C; Grav, T; Heasley, J N; Hodapp, K W; Jedicke, R; Kaiser, N; Kudritzki, R -P; Luppino, G A; Lupton, R H; Magnier, E A; Monet, D G; Morgan, J S; Onaka, P M; Price, P A; Stubbs, C W; Tonry, J L; Wainscoat, R J; Waterson, M F

    2011-01-01

    [abridged] We report on our serendipitous pre-discovery detection and detailed follow-up of the broad-lined Type Ic supernova SN 2010ay at z\\approx0.067 imaged by the Pan-STARRS1 3{\\pi} survey just \\sim3 days after explosion. We estimate the explosion date and the peak luminosity of the SN, MR\\approx-20.2 mag, significantly brighter than known GRB-SNe and one of the most luminous SNe Ic ever discovered. We measure the photospheric expansion velocity of the explosion, v_ph\\approx19.2x10^3 km/s at \\sim40 days after explosion. In comparison with other broad-lined SNe, the characteristic velocity of SN 2010ay is 2-5x higher and similar to the measurements for GRB-SNe at comparable epochs. Moreover the velocity declines two times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of 56 Ni, M_Ni=0.9+0.2 M_solar. Our modeling of the light-curve points to a total ejecta mass, Mej\\approx4.7M_so...

  3. Analysis of the multimer resolution system encoded by the parCBA operon of broad-host-range plasmid RP4

    DEFF Research Database (Denmark)

    Eberl, Leo; Sternberg, Claus; Givskov, Michael Christian;

    1994-01-01

    The broad-host-range plasmid RP4 encodes a highly efficient partitioning function, termed par, that is capable of stabilizing plasmids in a variety of Gram-negative bacteria independently of the nature of the replicon. The mechanism responsible for plasmid stabilization by this locus appears to be...... a complex system which includes a site-specific recombination system mediating resolution of plasmid multimers. In this report we present a detailed study on this multimer resolution system (mrs). The parA gene encodes two forms of a resolvase capable of catalysing site-specific recombination...

  4. Plasmid Evolution and Interaction between the Plasmid Addiction Stability Systems of Two Related Broad-Host-Range IncQ-Like Plasmids

    OpenAIRE

    Deane, Shelly M.; Rawlings, Douglas E

    2004-01-01

    Plasmid pTC-F14 contains a plasmid stability system called pas (plasmid addiction system), which consists of two proteins, a PasA antitoxin and a PasB toxin. This system is closely related to the pas of plasmid pTF-FC2 (81 and 72% amino acid identity for PasA and PasB, respectively) except that the pas of pTF-FC2 contains a third protein, PasC. As both pTC-F14 and pTF-FC2 are highly promiscuous broad-host-range plasmids isolated from bacteria that share a similar ecological niche, the plasmid...

  5. Functional difference between the two oppositely oriented priming signals essential for the initiation of the broad host-range plasmid RSF1010 DNA replication.

    OpenAIRE

    Tanaka, K.; Kino, K.; TAGUCHI, Y.; Miao, D M; Honda, Y; Sakai, H.; Komano, T; Bagdasarian, M

    1994-01-01

    The broad host-range plasmid RSF1010 contains two oppositely oriented priming signals, ssiA and ssiB, for DNA synthesis dependent on the origin of vegetative DNA replication (oriV). If either ssiA or ssiB was deleted or inverted, the RSF1010 miniplasmids containing engineered oriVs were maintained at low copy numbers, replicated abnormally as dimers, and accumulated specific single strands in the Escherichia coli strain supplying the three RSF1010-encoded RepA, RepB', and RepC proteins. Inter...

  6. A base-paired hairpin structure essential for the functional priming signal for DNA replication of the broad host range plasmid RSF1010.

    OpenAIRE

    Miao, D M; Honda, Y; Tanaka, K.; Higashi, A.; Nakamura, T.(International Center for Elementary Particle Physics and Department of Physics, The University of Tokyo, Tokyo, Japan); TAGUCHI, Y.; Sakai, H.; Komano, T; Bagdasarian, M

    1993-01-01

    The two single-strand DNA initiation signals, ssiA(RSF1010) and ssiB(RSF1010) of the broad host-range plasmid RSF1010 contain proposed stem-loop structures. Nine single base-change mutations in the stem of the ssiA structure, each of which destroyed a relevant base pairing, damaged the ssiA activity. A second single-base change was introduced into each of the nine ssiA mutants in such a way that the base pairing was restored. Only three out of nine second base changes that restored the base p...

  7. DnaG-dependent priming signals can substitute for the two essential DNA initiation signals in oriV of the broad host-range plasmid RSF1010.

    OpenAIRE

    Honda, Y; Nakamura, T.(International Center for Elementary Particle Physics and Department of Physics, The University of Tokyo, Tokyo, Japan); Tanaka, K.; Higashi, A.; Sakai, H.; Komano, T; Bagdasarian, M

    1992-01-01

    Broad host-range plasmid RSF1010 contains in the oriV region two DNA initiation signals, ssiA(RSF1010) and ssiB(RSF1010), which are essential for plasmid replication. Each of ssiA and ssiB could be substituted functionally by either of the two G4-type (DnaG-dependent) priming signals, the oric of bacteriophage G4 and an ssi signal from plasmid pSY343 (an R1 plasmid derivative). Functions of the chimeric oriVs of RSF1010 thus constructed were dependent on the RSF1010-specific replication prote...

  8. DISTRIBUTION OF ALGAL EPIPHYTES ACROSS ENVIRONMENTAL GRADIENTS AT DIFFERENT SCALES: INTERTIDAL ELEVATION, HOST CANOPIES, AND HOST FRONDS(1).

    Science.gov (United States)

    Longtin, Caroline M; Scrosati, Ricardo A; Whalen, Gillian B; Garbary, David J

    2009-08-01

    Understanding epiphyte distribution in coastal communities is important because these organisms affect many others directly or indirectly. Yet, their distribution has been considerably less studied than that of their hosts and other primary-space holders. Identifying major sources of variation in epiphyte abundance is thus still a need. Environmental gradients help predict species distribution and are pervasive on marine shores. In this study, we test the notion that environmental gradients across intertidal elevation, throughout host canopies, and along host fronds explain a large variation in the abundance of sympatric epiphytes. Our model system was the assemblage of Ascophyllum nodosum (L.) Le Jol. and its epiphytes Vertebrata lanosa (L.) T. A. Chr. [= Polysiphonia lanosa (L.) Tandy], Elachista fucicola (Velley) Aresch., and Pylaiella littoralis (L.) Kjellm. On the coast of Nova Scotia (Canada), we found evidence of a spatial segregation among these species at almost all scales. While the red epiphyte V. lanosa was more common at high- and midintertidal elevations (peaking at midelevations) and on middle segments of host fronds, the brown epiphytes E. fucicola and P. littoralis were more common at low elevations and restricted to distal segments of host fronds. Canopy habitat affected abundance only for V. lanosa, which was more common within the host canopy than on its periphery at midelevations. Since the studied gradients are related to predictable changes in abiotic factors, the identification of likely causes behind the observed patterns was facilitated. Our study ends by proposing abiotic and biotic factors that deserve priority in the experimental testing of the forces structuring this assemblage. PMID:27034211

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

    Science.gov (United States)

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

    2011-01-01

    The distribution pattern of species of the genus Dactylopius Costa in Mexico was analyzed in relation to the distribution of their host plants (subfamily Opuntioideae) to evaluate the specificity of the insect-host association. The distribution of Dactylopius currently recognized is narrower than that of its hosts and probably is not representative. Therefore, a broader distribution of the Dactylopius species in correspondence with those of their hosts was hypothesized. Insects and their hosts were collected and georeferenced in 14 states of Mexico from 2005 to 2007. The distribution areas, maps, and habitat characteristics of Dactylopius, Opuntia sensu stricto, Nopalea and Cylindropuntia were determined on the basis of field collections and examination of museum collections. This information was complemented with information from the exhaustive examination of microscope slides from a local insect collection, plants from local herbaria, and literature reviews. The current distribution of the genus Dactylopius and its hosts included 22 and 25 states of Mexico, respectively, and Dactylopius had a continuous distribution according to its hosts, broader than recognized hitherto. The new georeferenced records of the five Mexican Dactylopius species are reported. Insects with morphological characteristics of D. confusus combined with those of D. salmianus were identified, as well as insects with characteristics of D. opuntiae combined with those of D. salmianus. These records suggest that the number of local Dactylopius species could be higher than previously thought or that possible new processes of hybridization between native and introduced species may be occurring. PMID:21437484

  10. An Interferon Regulated MicroRNA Provides Broad Cell-Intrinsic Antiviral Immunity through Multihit Host-Directed Targeting of the Sterol Pathway.

    Directory of Open Access Journals (Sweden)

    Kevin A Robertson

    2016-03-01

    Full Text Available In invertebrates, small interfering RNAs are at the vanguard of cell-autonomous antiviral immunity. In contrast, antiviral mechanisms initiated by interferon (IFN signaling predominate in mammals. Whilst mammalian IFN-induced miRNA are known to inhibit specific viruses, it is not known whether host-directed microRNAs, downstream of IFN-signaling, have a role in mediating broad antiviral resistance. By performing an integrative, systematic, global analysis of RNA turnover utilizing 4-thiouridine labeling of newly transcribed RNA and pri/pre-miRNA in IFN-activated macrophages, we identify a new post-transcriptional viral defense mechanism mediated by miR-342-5p. On the basis of ChIP and site-directed promoter mutagenesis experiments, we find the synthesis of miR-342-5p is coupled to the antiviral IFN response via the IFN-induced transcription factor, IRF1. Strikingly, we find miR-342-5p targets mevalonate-sterol biosynthesis using a multihit mechanism suppressing the pathway at different functional levels: transcriptionally via SREBF2, post-transcriptionally via miR-33, and enzymatically via IDI1 and SC4MOL. Mass spectrometry-based lipidomics and enzymatic assays demonstrate the targeting mechanisms reduce intermediate sterol pathway metabolites and total cholesterol in macrophages. These results reveal a previously unrecognized mechanism by which IFN regulates the sterol pathway. The sterol pathway is known to be an integral part of the macrophage IFN antiviral response, and we show that miR-342-5p exerts broad antiviral effects against multiple, unrelated pathogenic viruses such Cytomegalovirus and Influenza A (H1N1. Metabolic rescue experiments confirm the specificity of these effects and demonstrate that unrelated viruses have differential mevalonate and sterol pathway requirements for their replication. This study, therefore, advances the general concept of broad antiviral defense through multihit targeting of a single host pathway.

  11. An Interferon Regulated MicroRNA Provides Broad Cell-Intrinsic Antiviral Immunity through Multihit Host-Directed Targeting of the Sterol Pathway.

    Science.gov (United States)

    Robertson, Kevin A; Hsieh, Wei Yuan; Forster, Thorsten; Blanc, Mathieu; Lu, Hongjin; Crick, Peter J; Yutuc, Eylan; Watterson, Steven; Martin, Kimberly; Griffiths, Samantha J; Enright, Anton J; Yamamoto, Mami; Pradeepa, Madapura M; Lennox, Kimberly A; Behlke, Mark A; Talbot, Simon; Haas, Jürgen; Dölken, Lars; Griffiths, William J; Wang, Yuqin; Angulo, Ana; Ghazal, Peter

    2016-03-01

    In invertebrates, small interfering RNAs are at the vanguard of cell-autonomous antiviral immunity. In contrast, antiviral mechanisms initiated by interferon (IFN) signaling predominate in mammals. Whilst mammalian IFN-induced miRNA are known to inhibit specific viruses, it is not known whether host-directed microRNAs, downstream of IFN-signaling, have a role in mediating broad antiviral resistance. By performing an integrative, systematic, global analysis of RNA turnover utilizing 4-thiouridine labeling of newly transcribed RNA and pri/pre-miRNA in IFN-activated macrophages, we identify a new post-transcriptional viral defense mechanism mediated by miR-342-5p. On the basis of ChIP and site-directed promoter mutagenesis experiments, we find the synthesis of miR-342-5p is coupled to the antiviral IFN response via the IFN-induced transcription factor, IRF1. Strikingly, we find miR-342-5p targets mevalonate-sterol biosynthesis using a multihit mechanism suppressing the pathway at different functional levels: transcriptionally via SREBF2, post-transcriptionally via miR-33, and enzymatically via IDI1 and SC4MOL. Mass spectrometry-based lipidomics and enzymatic assays demonstrate the targeting mechanisms reduce intermediate sterol pathway metabolites and total cholesterol in macrophages. These results reveal a previously unrecognized mechanism by which IFN regulates the sterol pathway. The sterol pathway is known to be an integral part of the macrophage IFN antiviral response, and we show that miR-342-5p exerts broad antiviral effects against multiple, unrelated pathogenic viruses such Cytomegalovirus and Influenza A (H1N1). Metabolic rescue experiments confirm the specificity of these effects and demonstrate that unrelated viruses have differential mevalonate and sterol pathway requirements for their replication. This study, therefore, advances the general concept of broad antiviral defense through multihit targeting of a single host pathway.

  12. Ultraviolet Broad Absorption Features and the Spectral Energy Distribution of the QSO PG 1351+64

    CERN Document Server

    Zheng, W; Wang, J X; Brotherton, M S; Oegerle, W R; Blair, W P; Davidsen, A F; Green, R F; Hutchings, J B; Kaiser, M E

    2001-01-01

    We present a moderate-resolution (~20 km/s) spectrum of the mini broad-absorption-line QSO PG1351+64 between 915-1180 A, obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Additional spectra at longer wavelengths were also obtained with the HST and ground-based telescopes. Broad absorption is present on the blue wings of CIII 977, Ly-beta, OVI 1032,1038, Ly-alpha, NV 1238,1242, SiIV 1393,1402, and CIV 1548,1450. The absorption profile can be fitted with five components at velocities of ~ -780, -1049, -1629, -1833, and -3054 km/s with respect to the emission-line redshift of z = 0.088. All the absorption components cover a large fraction of the continuum source as well as the broad-line region. The OVI emission feature is very weak, and the OVI/Lyalpha flux ratio is 0.08, one of the lowest among low-redshift active galaxies and QSOs. The UV continuum shows a significant change in slope near 1050 A in the restframe. The steeper continuum shortward of the Lyman limit extrapolates well to the observ...

  13. Climate-driven variation in the intensity of a host-symbiont animal interaction along a broad elevation gradient.

    Directory of Open Access Journals (Sweden)

    Leandro Meléndez

    Full Text Available Gradients of environmental stress may affect biotic interactions in unpredictable ways responding to climate variation, depending on the abiotic stress tolerance of interacting partners. Here, we study the effect of local climate on the intensity of feather mites in six mountain passerines along a 1400 m elevational gradient characterized by shifting temperature and rainfall. Although obligatory symbionts of warm-blooded organisms are assumed to live in mild and homeothermic environments, those inhabiting external, non-blood-irrigated body portions of the host organism, such as feather mites, are expected to endure exposure to the direct influence of a fluctuating climate. As expected, feather mite intensity declined with elevation in all bird species, a pattern that was also found in cold-adapted passerines that have typical alpine habits. The elevation cline was mainly explained by a positive effect of the average temperature upon mite intensity in five of the six species studied. Precipitation explained less variance in mite intensity than average temperature, and showed a negative correlation in half of the studied species. We found no climate-driven migration of mites along the wings of birds, no replacement of mite species along elevation gradients and no association with available food resources for mites (estimated by the size of the uropygial gland. This study suggests that ectosymbionts of warm-blooded animals may be highly sensitive to climatic variation and become less abundant under stressful environmental conditions, providing empirical evidence of the decline of specialized biotic interactions among animal species at high elevations.

  14. Complete nucleotide sequence and analysis of two conjugative broad host range plasmids from a marine microbial biofilm.

    Directory of Open Access Journals (Sweden)

    Peter Norberg

    Full Text Available The complete nucleotide sequence of plasmids pMCBF1 and pMCBF6 was determined and analyzed. pMCBF1 and pMCBF6 form a novel clade within the IncP-1 plasmid family designated IncP-1 ς. The plasmids were exogenously isolated earlier from a marine biofilm. pMCBF1 (62 689 base pairs; bp and pMCBF6 (66 729 bp have identical backbones, but differ in their mercury resistance transposons. pMCBF1 carries Tn5053 and pMCBF6 carries Tn5058. Both are flanked by 5 bp direct repeats, typical of replicative transposition. Both insertions are in the vicinity of a resolvase gene in the backbone, supporting the idea that both transposons are "res-site hunters" that preferably insert close to and use external resolvase functions. The similarity of the backbones indicates recent insertion of the two transposons and the ongoing dynamics of plasmid evolution in marine biofilms. Both plasmids also carry the insertion sequence ISPst1, albeit without flanking repeats. ISPs1is located in an unusual site within the control region of the plasmid. In contrast to most known IncP-1 plasmids the pMCBF1/pMCBF6 backbone has no insert between the replication initiation gene (trfA and the vegetative replication origin (oriV. One pMCBF1/pMCBF6 block of about 2.5 kilo bases (kb has no similarity with known sequences in the databases. Furthermore, insertion of three genes with similarity to the multidrug efflux pump operon mexEF and a gene from the NodT family of the tripartite multi-drug resistance-nodulation-division (RND system in Pseudomonas aeruginosa was found. They do not seem to confer antibiotic resistance to the hosts of pMCBF1/pMCBF6, but the presence of RND on promiscuous plasmids may have serious implications for the spread of antibiotic multi-resistance.

  15. Intrapopulational distribution of Meiogymnophallus minutus (Digenea, Gymnophallidae) infections in its first and second intermediate host.

    Science.gov (United States)

    Fermer, Jan; Culloty, Sarah C; Kelly, Thomas C; O'Riordan, Ruth M

    2009-10-01

    Host size and age are generally assumed to play a pivotal role in digenean trematode infection patterns, accounting for much of the variation found within intermediate host populations. However, knowledge is based on a limited number of studied host-parasite systems. We investigated the shell length class distribution of Meiogymnophallus minutus infections within populations of the first intermediate host Scrobicularia plana and second intermediate host Cerastoderma edule. Infections occurred very early in the life of the two intermediate hosts. Both prevalence and intensity of infections increased with host shell length and displayed extremely high values amongst large individuals. Whilst metacercarial infection patterns in juvenile C. edule could be best explained by differences in host shell length, in adult cockles, the effect of host age on infection levels prevailed. The microsporidian hyperparasite Unikaryon legeri, occurring in the metacercarial stage of M. minutus, was particularly abundant in aged cockles, strongly influencing infection patterns of the gymnophallid. Our results are consistent with the intrapopulational distribution reported from other digenean trematode parasites. The relative influence of both host size and age and the underlying mechanisms as well as the impact of hyperparasitism on M. minutus infection patterns are discussed.

  16. Complete Genome sequence of Burkholderia phymatum STM815, a broad host range and efficient nitrogen-fixing symbiont of Mimosa species

    Energy Technology Data Exchange (ETDEWEB)

    Moulin, Lionel [UMR, France; Klonowska, Agnieszka [UMR, France; Caroline, Bournaud [UMR, France; Booth, Kristina [University of Massachusetts; Vriezen, Jan A.C. [University of Massachusetts; Melkonian, Remy [UMR, France; James, Euan [James Hutton Institute, Dundee, United Kingdom; Young, Peter W. [University of York, United Kingdom; Bena, Gilles [UMR, France; Hauser, Loren John [ORNL; Land, Miriam L [ORNL; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Bruce, David [Los Alamos National Laboratory (LANL); Chain, Patrick S. G. [Lawrence Livermore National Laboratory (LLNL); Copeland, A [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Lizotte-Waniewski, Michelle [University of Massachusetts; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Riley, Monica [Woods Hole Oceanographic Institution (WHOI), Woods Hole

    2014-01-01

    Burkholderia phymatum is a soil bacterium able to develop a nitrogen-fixing symbiosis with species of the legume genus Mimosa, and is frequently found associated specifically with Mimosa pudica. The type strain of the species, STM 815T, was isolated from a root nodule in French Guiana in 2000. The strain is an aerobic, motile, non-spore forming, Gram-negative rod, and is a highly competitive strain for nodulation compared to other Mimosa symbionts, as it also nodulates a broad range of other legume genera and species. The 8,676,562 bp genome is composed of two chromosomes (3,479,187 and 2,697,374 bp), a megaplasmid (1,904,893 bp) and a plasmid hosting the symbiotic functions (595,108 bp).

  17. Eddington ratio Distribution of X-ray selected broad-line AGNs at 1.0

    CERN Document Server

    Suh, Hyewon; Steinhardt, Charles; Silverman, John D; Schramm, Malte

    2015-01-01

    We investigate the Eddington ratio distribution of X-ray selected broad-line active galactic nuclei (AGN) in the redshift range 1.0broad-line AGNs in the Chandra Deep Field-South (CDF-S), Extended Chandra Deep Field-South (E-CDF-S), and the XMM-Newton Lockman Hole (XMM-LH) surveys. AGNs with similar black hole masses show a broad range of AGN bolometric luminosities, which are calculated from X-ray luminosities, indicating that the accretion rate of black holes is widely distributed. We find that a substantial fraction of massive black holes accreting significantly below the Eddington limit at z~2, in contrast to what is generally found for luminous AGNs at high redshift. Our analysis of observational selection biases indicates that the "AGN cosmic downsizing" phenomenon can be simply explained by the strong evolution of the co-moving number density at the b...

  18. Effect of Comonomer Ethylene on Plateau Modulus of Crystalline Ethylene-propylene Random Copolymer with Broad Molecular Weight Distribution

    Institute of Scientific and Technical Information of China (English)

    丁健; 徐日炜; 丁雪佳; 余鼎声

    2005-01-01

    Ethylene-propylene random copolymer with ultra-high molecular weight (UHPPR) and broad molecular weight distribution (MWD) was prepared with Ziegler-Natta catalyst. The viscoelastic behavior of UHPPR has been investigated by means of oscillatory rheometer at 180, 200 and 220℃. The loss modulus (G"""") curves of 180 and 200℃ present a pronounced maximum at 38.10 and 84.70r/s, respectively, For the first time, this makes it possible to directly determine the plateau modulus ( GN0 ) of crystalline ethylene-propylene random copolymer with broad MWD in a certain experimental temperature G""""(w) curve. The plateau modulus of UHPPR is 4.51×105 and 3.67×105 Paat 180 and 200℃ respectively, increasing with random incorporation of comonomer ethylene into the molecular chains and being independent of molecular weight.

  19. Distributed Dynamic Host Configuration Protocol (D2HCP)

    OpenAIRE

    José Duván Márquez Díaz; Ana Lucila Sandoval Orozco; Luis Javier García Villalba; Julián García Matesanz

    2011-01-01

    Mobile Ad Hoc Networks (MANETs) are multihop wireless networks of mobile nodes without any fixed or preexisting infrastructure. The topology of these networks can change randomly due to the unpredictable mobility of nodes and their propagation characteristics. In most networks, including MANETs, each node needs a unique identifier to communicate. This work presents a distributed protocol for dynamic node IP address assignment in MANETs. Nodes of a MANET synchronize from time to time to mainta...

  20. Recovering galaxy stellar population properties from broad-band spectral energy distribution fitting

    CERN Document Server

    Pforr, Janine; Tonini, Chiara

    2012-01-01

    We explore the dependence of galaxy stellar population properties derived from broad-band SED-fitting - such as age, stellar mass, dust reddening, etc. - on a variety of parameters, such as SFHs, metallicity, IMF, dust reddening and reddening law, and wavelength coverage. Mock galaxies serve as test particles. We confirm our earlier results based on real z=2 galaxies, that usually adopted \\tau-models lead to overestimate the SFR and to underestimate the stellar mass. Here, we show that - for star-forming galaxies - ages, masses and reddening, can be well determined simultaneously only when the correct SFH is identified. This is the case for inverted-\\tau-models at high-z, for which we find that the mass recovery (at fixed IMF) is as good as ~0.04 dex. Since the right SFH is usually unknown we quantify offsets generated by adopting standard fitting setups. Stellar masses are generally underestimated resulting from underestimating ages. For fitting setups with a variety of SFHs the median mass recovery at z ~ 2...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    to climate change. Here, we combine a growing degree day model for Schistosoma mansoni with species distribution models for the intermediate host snail (Biomphalaria spp.) to investigate large-scale environmental determinants of the distribution of the African S. mansoni-Biomphalaria system and potential...

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

    Science.gov (United States)

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

    2016-01-01

    Epiphytes are strongly dependent on the conditions created by their host's traits and a certain degree of specificity is expected between them, even if these species are largely abundant in a series of tree hosts of a given environment, as in the case of atmospheric bromeliads. Despite their considerable abundance in these environments, we hypothesize that stochasticity alone cannot explain the presence and abundance of atmospheric bromeliads on host trees, since host traits could have a greater influence on the establishment of these bromeliads. We used secondary and reforested seasonal forests and three distinct silvicultures to test whether species richness, phylogenetic diversity and functional diversity of trees can predict the differential presence, abundance and distribution of atmospheric bromeliads on hosts. We compared the observed parameters of their assemblage with null models and performed successive variance hierarchic partitions of abundance and distribution of the assemblage to detect the influence of multiple traits of the tree hosts. Our results do not indicate direct relationships between the abundance of atmospheric bromeliads and phylogenetic or functional diversity of trees, but instead indicate that bromeliads occurred on fewer tree species than expected by chance. We distinguished functional tree patterns that can improve or reduce the abundance of atmospheric bromeliads, and change their distribution on branches and trunk. While individual tree traits are related to increased abundance, species traits are related to the canopy distribution of atmospheric bromeliad assemblages. A balance among these tree functional patterns drives the atmospheric bromeliad assemblage of the forest patches. PMID:26888951

  3. Megamaser Disks Reveal a Broad Distribution of Black Hole Mass in Spiral Galaxies

    Science.gov (United States)

    Greene, J. E.; Seth, A.; Kim, M.; Läsker, R.; Goulding, A.; Gao, F.; Braatz, J. A.; Henkel, C.; Condon, J.; Lo, K. Y.; Zhao, W.

    2016-08-01

    We use new precision measurements of black hole (BH) masses from water megamaser disks to investigate scaling relations between macroscopic galaxy properties and supermassive BH mass. The megamaser-derived BH masses span 106-108 {M}⊙ , while all the galaxy properties that we examine (including total stellar mass, central mass density, and central velocity dispersion) lie within a narrower range. Thus, no galaxy property correlates tightly with {M}{BH} in ˜L* spiral galaxies as traced by megamaser disks. Of them all, stellar velocity dispersion provides the tightest relation, but at fixed {σ }* the mean megamaser {M}{BH} are offset by -0.6 ± 0.1 dex relative to early-type galaxies. Spiral galaxies with non-maser dynamical BH masses do not appear to show this offset. At low mass, we do not yet know the full distribution of BH mass at fixed galaxy property; the non-maser dynamical measurements may miss the low-mass end of the BH distribution due to an inability to resolve their spheres of influence and/or megamasers may preferentially occur in lower-mass BHs.

  4. Megamaser Disks Reveal a Broad Distribution of Black Hole Mass in Spiral Galaxies

    CERN Document Server

    Greene, Jenny E; Kim, Minjin; Laesker, Ronald; Goulding, Andy D; Gao, Feng; Braatz, James A; Henkel, Christian; Condon, James; Lo, Fred K Y; Zhao, Wei

    2016-01-01

    We use new precision measurements of black hole masses from water megamaser disks to investigate scaling relations between macroscopic galaxy properties and supermassive black hole (BH) mass. The megamaser-derived BH masses span 10^6-10^8 M_sun, while all the galaxy properties that we examine (including stellar mass, central mass density, central velocity dispersion) lie within a narrow range. Thus, no galaxy property correlates tightly with M_BH in ~L* spiral galaxies. Of them all, stellar velocity dispersion provides the tightest relation, but at fixed sigma* the mean megamaser M_BH are offset by -0.6+/-0.1 dex relative to early-type galaxies. Spiral galaxies with non-maser dynamical BH masses do not show this offset. At low mass, we do not yet know the full distribution of BH mass at fixed galaxy property; the non-maser dynamical measurements may miss the low-mass end of the BH distribution due to inability to resolve the spheres of influence and/or megamasers may preferentially occur in lower-mass BHs.

  5. Distributed Dynamic Host Configuration Protocol (D2HCP).

    Science.gov (United States)

    Villalba, Luis Javier García; Matesanz, Julián García; Orozco, Ana Lucila Sandoval; Díaz, José Duván Márquez

    2011-01-01

    Mobile Ad Hoc Networks (MANETs) are multihop wireless networks of mobile nodes without any fixed or preexisting infrastructure. The topology of these networks can change randomly due to the unpredictable mobility of nodes and their propagation characteristics. In most networks, including MANETs, each node needs a unique identifier to communicate. This work presents a distributed protocol for dynamic node IP address assignment in MANETs. Nodes of a MANET synchronize from time to time to maintain a record of IP address assignments in the entire network and detect any IP address leaks. The proposed stateful autoconfiguration scheme uses the OLSR proactive routing protocol for synchronization and guarantees unique IP addresses under a variety of network conditions, including message losses and network partitioning. Simulation results show that the protocol incurs low latency and communication overhead for IP address assignment. PMID:22163856

  6. Assessing the status and trend of bat populations across broad geographic regions with dynamic distribution models

    Science.gov (United States)

    Rodhouse, Thomas J.; Ormsbee, Patricia C.; Irvine, Kathryn M.; Vierling, Lee A.; Szewczak, Joseph M.; Vierling, Kerri T.

    2012-01-01

    Bats face unprecedented threats from habitat loss, climate change, disease, and wind power development, and populations of many species are in decline. A better ability to quantify bat population status and trend is urgently needed in order to develop effective conservation strategies. We used a Bayesian autoregressive approach to develop dynamic distribution models for Myotis lucifugus, the little brown bat, across a large portion of northwestern USA, using a four-year detection history matrix obtained from a regional monitoring program. This widespread and abundant species has experienced precipitous local population declines in northeastern USA resulting from the novel disease white-nose syndrome, and is facing likely range-wide declines. Our models were temporally dynamic and accounted for imperfect detection. Drawing on species–energy theory, we included measures of net primary productivity (NPP) and forest cover in models, predicting that M. lucifugus occurrence probabilities would covary positively along those gradients.

  7. A Multi-wavelength Survey of AGN in Massive Clusters: AGN Distribution and Host Galaxy Properties

    CERN Document Server

    Klesman, Alison J

    2014-01-01

    We investigate the effect of environment on the presence and fuelling of Active Galactic Nuclei (AGN) by identifying galaxies hosting AGN in massive galaxy clusters and the fields around them. We have identified AGN candidates via optical variability (178), X-ray emission (74), and mid-IR SEDs (64) in multi- wavelength surveys covering regions centered on 12 galaxy clusters at redshifts 0.5 < z < 0.9. In this paper, we present the radial distribution of AGN in clusters to examine how local environment affects the presence of an AGN and its host galaxy. While distributions vary from cluster to cluster, we find that the radial distribution of AGN generally differs from that of normal galaxies. AGN host galaxies also show a different colour distribution than normal galaxies, with many AGN hosts displaying galaxy colours in the "green valley" between the red sequence and blue star-forming normal galaxies. This result is similar to those found in field galaxy studies. The colour distribution of AGN hosts is ...

  8. Four-dimensional symmetry from a broad viewpoint. II Invariant distribution of quantized field oscillators and questions on infinities

    Science.gov (United States)

    Hsu, J. P.

    1983-01-01

    The foundation of the quantum field theory is changed by introducing a new universal probability principle into field operators: one single inherent and invariant probability distribution P(/k/) is postulated for boson and fermion field oscillators. This can be accomplished only when one treats the four-dimensional symmetry from a broad viewpoint. Special relativity is too restrictive to allow such a universal probability principle. A radical length, R, appears in physics through the probability distribution P(/k/). The force between two point particles vanishes when their relative distance tends to zero. This appears to be a general property for all forces and resembles the property of asymptotic freedom. The usual infinities in vacuum fluctuations and in local interactions, however complicated they may be, are all removed from quantum field theories. In appendix A a simple finite and unitary theory of unified electroweak interactions is discussed without assuming Higgs scalar bosons.

  9. Recurrent evolution of host-specialized races in a globally distributed parasite

    OpenAIRE

    McCoy, Karen D.; Chapuis, Elodie; Tirard, Claire; Boulinier, Thierry; Michalakis, Yannis; Bohec, Céline Le; Maho, Yvon Le; Gauthier-Clerc, Michel

    2005-01-01

    The outcome of coevolutionary interactions is predicted to vary across landscapes depending on local conditions and levels of gene flow, with some populations evolving more extreme specializations than others. Using a globally distributed parasite of colonial seabirds, the tick Ixodes uriae, we examined how host availability and geographic isolation influences this process. In particular, we sampled ticks from 30 populations of six different seabird host species, three in the Southern Hemisph...

  10. Isolation and characterization of insertion sequence elements from gram-negative bacteria by using new broad-host-range, positive selection vectors.

    Science.gov (United States)

    Simon, R; Hötte, B; Klauke, B; Kosier, B

    1991-01-01

    On the basis of an RSF1010-derived broad-host-range vector, three different systems which enable positive detection and isolation of insertion sequence (IS) elements from gram-negative bacteria were constructed. Vectors pSUP104-pheS, pSUP104-rpsL, and pSUP104-sac were used successfully in a number of Rhizobium strains and in Xanthomonas campestris. More than 20 different IS elements were isolated and characterized. The 16 IS elements from Rhizobium meliloti were further used to characterize various R. meliloti strains by hybridization. The resulting hybridization patterns were different for every strain and gave a clear and definite IS fingerprint of each strain. These IS fingerprints can be used to identify and characterize R. meliloti strains rapidly and unequivocally, as they proved to be relatively stable. Some of the IS elements were found to be identical when the IS fingerprints from a given strain were compared. This method of IS fingerprinting can also establish whether IS elements are the same, related, or different. Images PMID:1847366

  11. Isolation and characterization of insertion sequence elements from gram-negative bacteria by using new broad-host-range, positive selection vectors.

    Science.gov (United States)

    Simon, R; Hötte, B; Klauke, B; Kosier, B

    1991-02-01

    On the basis of an RSF1010-derived broad-host-range vector, three different systems which enable positive detection and isolation of insertion sequence (IS) elements from gram-negative bacteria were constructed. Vectors pSUP104-pheS, pSUP104-rpsL, and pSUP104-sac were used successfully in a number of Rhizobium strains and in Xanthomonas campestris. More than 20 different IS elements were isolated and characterized. The 16 IS elements from Rhizobium meliloti were further used to characterize various R. meliloti strains by hybridization. The resulting hybridization patterns were different for every strain and gave a clear and definite IS fingerprint of each strain. These IS fingerprints can be used to identify and characterize R. meliloti strains rapidly and unequivocally, as they proved to be relatively stable. Some of the IS elements were found to be identical when the IS fingerprints from a given strain were compared. This method of IS fingerprinting can also establish whether IS elements are the same, related, or different.

  12. Complete genome sequence of the N2-fixing broad host range endophyte Klebsiella pneumoniae 342 and virulence predictions verified in mice.

    Science.gov (United States)

    Fouts, Derrick E; Tyler, Heather L; DeBoy, Robert T; Daugherty, Sean; Ren, Qinghu; Badger, Jonathan H; Durkin, Anthony S; Huot, Heather; Shrivastava, Susmita; Kothari, Sagar; Dodson, Robert J; Mohamoud, Yasmin; Khouri, Hoda; Roesch, Luiz F W; Krogfelt, Karen A; Struve, Carsten; Triplett, Eric W; Methé, Barbara A

    2008-01-01

    We report here the sequencing and analysis of the genome of the nitrogen-fixing endophyte, Klebsiella pneumoniae 342. Although K. pneumoniae 342 is a member of the enteric bacteria, it serves as a model for studies of endophytic, plant-bacterial associations due to its efficient colonization of plant tissues (including maize and wheat, two of the most important crops in the world), while maintaining a mutualistic relationship that encompasses supplying organic nitrogen to the host plant. Genomic analysis examined K. pneumoniae 342 for the presence of previously identified genes from other bacteria involved in colonization of, or growth in, plants. From this set, approximately one-third were identified in K. pneumoniae 342, suggesting additional factors most likely contribute to its endophytic lifestyle. Comparative genome analyses were used to provide new insights into this question. Results included the identification of metabolic pathways and other features devoted to processing plant-derived cellulosic and aromatic compounds, and a robust complement of transport genes (15.4%), one of the highest percentages in bacterial genomes sequenced. Although virulence and antibiotic resistance genes were predicted, experiments conducted using mouse models showed pathogenicity to be attenuated in this strain. Comparative genomic analyses with the presumed human pathogen K. pneumoniae MGH78578 revealed that MGH78578 apparently cannot fix nitrogen, and the distribution of genes essential to surface attachment, secretion, transport, and regulation and signaling varied between each genome, which may indicate critical divergences between the strains that influence their preferred host ranges and lifestyles (endophytic plant associations for K. pneumoniae 342 and presumably human pathogenesis for MGH78578). Little genome information is available concerning endophytic bacteria. The K. pneumoniae 342 genome will drive new research into this less-understood, but important category

  13. Complete genome sequence of the N2-fixing broad host range endophyte Klebsiella pneumoniae 342 and virulence predictions verified in mice.

    Directory of Open Access Journals (Sweden)

    Derrick E Fouts

    Full Text Available We report here the sequencing and analysis of the genome of the nitrogen-fixing endophyte, Klebsiella pneumoniae 342. Although K. pneumoniae 342 is a member of the enteric bacteria, it serves as a model for studies of endophytic, plant-bacterial associations due to its efficient colonization of plant tissues (including maize and wheat, two of the most important crops in the world, while maintaining a mutualistic relationship that encompasses supplying organic nitrogen to the host plant. Genomic analysis examined K. pneumoniae 342 for the presence of previously identified genes from other bacteria involved in colonization of, or growth in, plants. From this set, approximately one-third were identified in K. pneumoniae 342, suggesting additional factors most likely contribute to its endophytic lifestyle. Comparative genome analyses were used to provide new insights into this question. Results included the identification of metabolic pathways and other features devoted to processing plant-derived cellulosic and aromatic compounds, and a robust complement of transport genes (15.4%, one of the highest percentages in bacterial genomes sequenced. Although virulence and antibiotic resistance genes were predicted, experiments conducted using mouse models showed pathogenicity to be attenuated in this strain. Comparative genomic analyses with the presumed human pathogen K. pneumoniae MGH78578 revealed that MGH78578 apparently cannot fix nitrogen, and the distribution of genes essential to surface attachment, secretion, transport, and regulation and signaling varied between each genome, which may indicate critical divergences between the strains that influence their preferred host ranges and lifestyles (endophytic plant associations for K. pneumoniae 342 and presumably human pathogenesis for MGH78578. Little genome information is available concerning endophytic bacteria. The K. pneumoniae 342 genome will drive new research into this less-understood, but

  14. Recovering galaxy stellar population properties from broad-band spectral energy distribution fitting II. The case with unknown redshift

    CERN Document Server

    Pforr, Janine; Tonini, Chiara

    2013-01-01

    (Abridged) In a recent work we explored the dependence of galaxy stellar population properties derived from broad-band spectral energy distribution fitting on the fitting parameters, e.g. SFHs, age grid, metallicity, IMF, dust reddening, reddening law, filter setup and wavelength coverage. In this paper we consider also redshift as a free parameter in the fit and study whether one can obtain reasonable estimates of photometric redshifts and stellar population properties at once. We use mock star-forming as well as passive galaxies placed at various redshifts (0.5 to 3) as test particles. Mock star-forming galaxies are extracted from a semi-analytical galaxy formation model. We show that for high-z star-forming galaxies photometric redshifts, stellar masses and reddening can be determined simultaneously when using a broad wavelength coverage and a wide template setup in the fit. Masses are similarly well recovered (median ~ 0.2 dex) as at fixed redshift. For old galaxies with little recent star formation masse...

  15. Distribution of the intermediate hosts of Echinococcus multilocularis in Shiqu County, Sichuan, China

    Institute of Scientific and Technical Information of China (English)

    XU Xiang; GUAN Ya-yi; TIAN Tian; WU Wei-ping; WANG Qian; HUANG Yan; LI Guang-qing; WANG Li-ying

    2011-01-01

    Background The rodentia and lagomorpha animals are the intermediate hosts of Echinococcus multilocularis, their distribution and infection of this parasite may facilitate the infection of definitive hosts such as dogs. The aim of this study was to determine the distribution of the intermediate hosts of Echinococcus multilocularis in Shiqu County, Sichuan, China.Methods A systematic sampling method was used to investigate the density of burrows of rodents and lagomorphs at 97 pasture sites in winter and summer pastureland and remote sensing (RS) technology was used to correlate their densities to the distribution of these animals in different landscape types.Results Based on the densities of Ochotona curzoniae, Microtus fuscus (dependent variable) and their burrow densities (independent variable) in survey points, regression equations were fitted respectively (Ochotona curzoniae, P<0.0001, R2=0.8705; Microtus fuscus, P <0.0001, R2=0.9736). Their burrow density in summer pastureland was higher than in winter pastureland (F=36.65, P <0.0001). The burrow densities of Ochotona curzoniae and Microtus fuscus in bareland and half-bareland are higher than in grassland (F=7.73, P <0.001).Conclusions The regression relationship between the densities of Ochotona curzoniae and Microtus fuscus and their burrow densities indicate that the burrow densities could reflect the animal densities and that the burrow density was greater in summer pastureland than in winter pastureland. The main distribution areas of the intermediate hosts were in bareland and half-bareland.

  16. Construction and use of a versatile set of broad-host-range cloning and expression vectors based on the RK2 replicon.

    Science.gov (United States)

    Blatny, J M; Brautaset, T; Winther-Larsen, H C; Haugan, K; Valla, S

    1997-01-01

    The plasmid vectors described in this report are derived from the broad-host-range RK2 replicon and can be maintained in many gram-negative bacterial species. The complete nucleotide sequences of all of the cloning and expression vectors are known. Important characteristics of the cloning vectors are as follows: a size range of 4.8 to 7.1 kb, unique cloning sites, different antibiotic resistance markers for selection of plasmid-containing cells, oriT-mediated conjugative plasmid transfer, plasmid stabilization functions, and a means for a simple method for modification of plasmid copy number. Expression vectors were constructed by insertion of the inducible Pu or Pm promoter together with its regulatory gene xylR or xylS, respectively, from the TOL plasmid of Pseudomonas putida. One of these vectors was used in an analysis of the correlation between phosphoglucomutase activity and amylose accumulation in Escherichia coli. The experiments showed that amylose synthesis was only marginally affected by the level of basal expression from the Pm promoter of the Acetobacter xylinum phosphoglucomutase gene (celB). In contrast, amylose accumulation was strongly reduced when transcription from Pm was induced. CelB was also expressed with a very high induction ratio in Xanthomonas campestris. These experiments showed that the A. xylinum celB gene could not complement the role of the bifunctional X. campestris phosphoglucomutase-phosphomannomutase gene in xanthan biosynthesis. We believe that the vectors described here are useful for cloning experiments, gene expression, and physiological studies with a wide range of bacteria and presumably also for analysis of gene transfer in the environment. PMID:9023917

  17. Broad-Host-Range Plasmids for Red Fluorescent Protein Labeling of Gram-Negative Bacteria for Use in the Zebrafish Model System▿ †

    Science.gov (United States)

    Singer, John T.; Phennicie, Ryan T.; Sullivan, Matthew J.; Porter, Laura A.; Shaffer, Valerie J.; Kim, Carol H.

    2010-01-01

    To observe real-time interactions between green fluorescent protein-labeled immune cells and invading bacteria in the zebrafish (Danio rerio), a series of plasmids was constructed for the red fluorescent protein (RFP) labeling of a variety of fish and human pathogens. The aim of this study was to create a collection of plasmids that would express RFP pigments both constitutively and under tac promoter regulation and that would be nontoxic and broadly transmissible to a variety of Gram-negative bacteria. DNA fragments encoding the RFP dimeric (d), monomeric (m), and tandem dimeric (td) derivatives d-Tomato, td-Tomato, m-Orange, and m-Cherry were cloned into the IncQ-based vector pMMB66EH in Escherichia coli. Plasmids were mobilized into recipient strains by conjugal mating. Pigment production was inducible in Escherichia coli, Pseudomonas aeruginosa, Edwardsiella tarda, and Vibrio (Listonella) anguillarum strains by isopropyl-β-d-thiogalactopyranoside (IPTG) treatment. A spontaneous mutant exconjugant of P. aeruginosa PA14 was isolated that expressed td-Tomato constitutively. Complementation analysis revealed that the constitutive phenotype likely was due to a mutation in lacIq carried on pMMB66EH. DNA sequence analysis confirmed the presence of five transitions, four transversions, and a 2-bp addition within a 14-bp region of lacI. Vector DNA was purified from this constitutive mutant, and structural DNA sequences for RFP pigments were cloned into the constitutive vector. Exconjugants of P. aeruginosa, E. tarda, and V. anguillarum expressed all pigments in an IPTG-independent fashion. Results from zebrafish infectivity studies indicate that RFP-labeled pathogens will be useful for the study of real-time interactions between host cells of the innate immune system and the infecting pathogen. PMID:20363780

  18. The distribution of parasite strains among hosts affects disease spread in a social insect.

    Science.gov (United States)

    Ulrich, Yuko; Schmid-Hempel, Paul

    2015-06-01

    Social insects present highly interesting and experimentally amenable systems for the study of disease transmission because they naturally live in dense groups of frequently interacting individuals. Using experimental inoculations of five trypanosomatid strains into groups of its natural host, the bumblebee Bombus terrestris, we investigate the effects of the initial parasite strain distribution across group members on the establishment and transmission success of the different strains to new hosts. For a given number of parasite strains circulating within a host group, transmission to new hosts was increased when the strains were initially inoculated as mixed infections (as opposed to separate single infections), presumably because mixed infections generally favored fast replicating strains. In contrast, separate single infections reduced transmission at least in part through a precedence effect, whereby weak strains appeared to persist by making their host unavailable to superinfection. These results suggest that host groups could benefit from 'compartmentalizing' infections by different parasite strains across different group members, which might be achieved in social insects, for example, by division of labor. PMID:25858120

  19. Multigroup discrete ordinates modeling of 125I 6702 seed dose distributions using a broad energy-group cross section representation.

    Science.gov (United States)

    Daskalov, George M; Baker, R S; Rogers, D W O; Williamson, J F

    2002-02-01

    Our purpose in this work is to demonstrate that the efficiency of dose-rate computations in 125I brachytherapy, using multigroup discrete ordinates radiation transport simulations, can be significantly enhanced using broad energy group cross sections without a loss of accuracy. To this end, the DANTSYS multigroup discrete ordinates neutral particle transport code was used to estimate the absorbed dose-rate distributions around an 125I-model 6702 seed in two-dimensional (2-D) cylindrical R-Z geometry for four different problems spanning the geometries found in clinical practice. First, simulations with a high resolution 210 energy groups library were used to analyze the photon flux spectral distribution throughout this set of problems. These distributions were used to design an energy group structure consisting of three broad groups along with suitable weighting functions from which the three-group cross sections were derived. The accuracy of 2-D DANTSYS dose-rate calculations was benchmarked against parallel Monte Carlo simulations. Ray effects were remedied by using the DANTSYS internal first collision source algorithm. It is demonstrated that the 125I primary photon spectrum leads to inappropriate weighting functions. An accuracy of +/-5% is achieved in the four problem geometries considered using geometry-independent three-group libraries derived from either material-specific weighting functions or a single material-independent weighting function. Agreement between Monte Carlo and the three-group DANTSYS calculations, within three standard Monte Carlo deviations, is observed everywhere except for a limited region along the Z axis of rotational symmetry, where ray effects are difficult to mitigate. The three-group DANTSYS calculations are 10-13 times faster than ones with a 210-group cross section library for 125I dosimetry problems. Compared to 2-D EGS4 Monte Carlo calculations, the 3-group DANTSYS simulations are a 100-fold more efficient. Provided that these

  20. Studies on Material Cycling in Evergreen Broad-Leaved Forest Ecosystem in Hangzhou:I.Precipitation Distribution

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    Through the long-term plot studies plot studies on the precipitation distribution in the evergreen broad-leaved forest ecosystem in Hangzhou for two years,it was indicated that the pattern of precipitation distribution included larger amounts of penetration water and stemflow and a lower amount of interception water.The results revealed that the main factors to infulence the percentages of penetration and stemflow were the air temperature and the leaf area of the forest.The quantity of seepage through the litter layer was much larger than that through the soil layers which decreased sharply with soil depth.The output of water from the ecosystem by surface runoff and deep infiltration through the soil was much lower,only being 5.20 percent of the rainfall,while the water evapotranspiration loss was as large as more than 90 percent of it.The losses by the soil evaporation and plant evapotranspiration were the largest part of output in this forest ecosystem.

  1. Sipha maydis: distribution and host range of a new aphid pest of winter cereals in Argentina.

    Science.gov (United States)

    Corrales, C E; Castro, A M; Ricci, M; Dixon, A F G

    2007-12-01

    Sipha maydis (Passerini) is a new aphid pest of cereals and cultivated and wild grasses in Argentina. This species was recently introduced into America, and nothing is known of its distribution or host range in South America. A better understanding of its biology is likely to facilitate control. This article records 1) the distribution and 2) the host range of S. maydis in Argentina. Over the period 2004-2006 samples were collected from 32 populations at several localities in Argentina. The number of S. maydis, accompanying aphid species, and the host from which they were collected were recorded. The distribution of S. maydis ranged from 32 degrees 52' to 42 degrees 03' S, and from 57 degrees 41' to 71 degrees 24' W, bounded by isothermals 18 and 10 degrees C and isohyets 200-400 and Sorghum halepense (L.) Pers. No aphids were found on maize, Zea mays L. Most of the damage to winter cereal crops occurred at the seedling stage in early autumn and of adult plants when infestations occurred in late spring. In the 4 yr after the first record of S. maydis in Argentina, it colonized a huge area similar to that colonized by Diuraphis noxia (Mordvilko) in 10 yr. The wide range of regions, hosts and climatic conditions this species is adapted to is likely to make the control of this pest very difficult.

  2. Broad-band spectral energy distribution of 3000 Å break quasars from the Sloan Digital Sky Survey

    Science.gov (United States)

    Meusinger, H.; Schalldach, P.; Mirhosseini, A.; Pertermann, F.

    2016-03-01

    Context. In past decades, huge surveys have confirmed the existence of populations of exotic and hitherto unknown quasar types. The discovery and investigation of these rare peculiar objects is important because they may represent links to special evolutionary stages and hold clues to the evolution of quasars and galaxies. Aims: The Sloan Digital Sky Survey (SDSS) discovered the unusual quasars J010540.75-003313.9 and J220445.27+003141.8 and a small number of similar objects. Their spectra are characterised by a break in the continuum around 3000 Å that neither shows the typical structure of broad absorption line (BAL) troughs nor is explained by typical intrinsic dust reddening. The main aim of the present paper was twofold. First, a new target-oriented search was performed in the spectra database of the SDSS to construct a sizable sample of such 3000 Å break quasars. Second, their broad-band spectral energy distribution (SED) was compared with SEDs of BAL quasars. Methods: We used the method of Kohonen self-organising maps for data mining in the SDSS spectra archive to search for more quasars with properties comparable to the prototypes J010540.75-003313.9 and J220445.27+003141.8. We constructed a sample of 3000 Å break quasars and comparison samples of quasars with similar properties, to some extent, but also showing indications for typical BAL features. Particular attention was payed to a possible contamination by rare stellar spectral types, in particular DQ white dwarfs. We construct ensemble-averaged broad-band SEDs based on archival data from SDSS, GALEX, 2MASS, UKIDSS, WISE, and other surveys. The SEDs were corrected for dust absorption at the systemic redshifts of the quasars by the comparison with the average SED of normal quasars. Results: We compiled a list of 23 quasars classified as 3000 Å break quasars with properties similar to 010540.75-003313.9 and J220445.27+003141.8. Their de-reddened arithmetic median composite SED is indistinguishable

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-08-03

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

  5. Expanded Host Diversity and Geographic Distribution of Hantaviruses in Sub-Saharan Africa

    OpenAIRE

    Kang, Hae Ji; Stanley, William T.; Esselstyn, Jacob A.; Gu, Se Hun; Yanagihara, Richard

    2014-01-01

    The recent discovery of hantaviruses in shrews and bats in West Africa suggests that other genetically distinct hantaviruses exist in East Africa. Genetic and phylogenetic analyses of newfound hantaviruses, detected in archival tissues from the Geata mouse shrew (Myosorex geata) and Kilimanjaro mouse shrew ( Myosorex zinki) captured in Tanzania, expands the host diversity and geographic distribution of hantaviruses and suggests that ancestral shrews and/or bats may have served as the origi...

  6. Distribution, Hosts, and Morphological Characteristics of Tylenchulus palustris in Florida and Bermuda

    OpenAIRE

    Dow, Roberta L.; Inserra, R. N.; Esser, R. P.; Langdon, K. R.

    1990-01-01

    Studies on the geographical distribution and hosts of Tylenchulus palustris were conducted over a 3-year period in Florida and Bermuda. Tylenchulus palustris was found on Aster elliottii and Liquidambar styraciflua roots in swamps of northern and central Florida. It was detected also on Borrichia arborescens and B. frutescens roots in tidal marshes of northern Florida and coastal rocklands of southern Florida and Bermuda. Posterior bodies of T. palustris swollen females from Bermuda did not d...

  7. The regional distribution regularities of ore-hosting horizon, deposit type and mineralization age of China's sandstone-hosted uranium deposits

    International Nuclear Information System (INIS)

    The sandstone-hosted uranium deposits widespread in China's Meso-Cenozoic sedimentary basins are obviously different from each other in ore-hosting horizon, deposit type (ore-forming process) and in the spatial distribution of mineralization ages. All the above changes are originated from the specific characteristics of the tectonic evolution of each tectonic domain where the deposits occur, obeying the affect resulting from the collision of Indian plate and the subduction of Pacific plate respectively. Basins and sandstone-hosted uranium deposits in the Central domain are effected of both Indian and Pacific plates, and are of characteristics of the two metallogenic systems. (authors)

  8. Spatial distributions of the leafminer Ophiomyia maura (Diptera: Agromyzidae) in host plant Aster ageratoides

    Institute of Scientific and Technical Information of China (English)

    Yoshiko Ayabe; Ei'ichi Shibata

    2008-01-01

    The seasonal occurrence and among-plant and within-plant spatial distribution of the multivoltine leafminer Ophiomyia maura Meigen (Diptera: Agromyzidae) on the herbaceous plant Aster ageratoides Turcz. subsp, ovatus (Asteraceae) were investigated in the field. O. maura has at least four generations a year and mines per leaf fluctuate with a mean of 0.007 throughout the occurrence period. Seasonal occurrence is associated with abundance of new host leaves, suggesting O. maura females prefer to oviposit in newly emerged leaves. The among-plant distribution of O. maura is described by a Poisson distribution early in the season but tends to be weakly clumped later. The within-plant vertical distribution of larval mines increased from middle to upper leaves during plantdevelopment, because mined leaves in the middle position early in the season move downward with the emergence of new leaves, shifting mined leaves from the position where O. maura oviposits eggs. Later in the season, mined leaves remain where they are deposited because few new leaves emerge. The spatial distribution of O. rnaura, resource utilization patterns, and host plant characteristics are discussed.

  9. An ancient family of SelB elongation factor-like proteins with a broad but disjunct distribution across archaea

    Directory of Open Access Journals (Sweden)

    Hauryliuk Vasili

    2011-01-01

    RNA and GTP. Therefore, change in tRNA specificity of aSelBL could have disrupted its GTPase cycle, leading to relaxation of selective pressure on the GTPase domain and explaining its apparent degradation. While the specific role of aSelBL is yet to be experimentally tested, its broad phylogenetic distribution, surpassing that of aSelB, indicates its importance.

  10. Distribution and host diversity of Amoebophryidae parasites across oligotrophic waters of the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    L. Guillou

    2010-10-01

    Full Text Available Sequences affiliated to Syndiniales (Marine alveolate, MALV regularly dominate 18S rDNA genetic libraries of nearly all marine ecosystems investigated so far. Among them, Amoebophryidae (MALV group II is composed of numerous and genetically distant environmental sequences, where Amoebophrya is the only known and formally described genus. Amoebophrya species include virulent pathogens for a wide range of dinoflagellate species. Beside their regular occurrence in marine ecosystems, their quantitative distribution and the environmental factors triggering host infection have barely been studied in open oligotrophic waters. In order to understand the functional role of these parasites in natural environments, we studied the distribution and contribution to the eukaryotic community of the small free-living stage of Amoebophryidae (the dinospores along a transect in the Mediterranean Sea, as well as their host diversity at three oligotrophic stations. Dinospores were more abundant at a coastal station (max. 1.5 × 103 cells ml−1 than in oligotrophic waters (max. 51 ± 16.3 cells ml−1, where they represented 10.3 to 34.9% of the total eukaryotic community at 40 and 30 m depth, respectively and 21.2% on average along the water column. Positive correlation was found between dinospore occurrence and higher concentration of NO3 + NO2 at the coastal station. At selected stations, out of 38 different dinoflagellates taxa identified, 15 were infected, among which a majority were not recognized as Amoebophryidae host so far. Prevalences (percentage of infected cells generally varied between 2% and 10%, with a notable exception for Blepharocysta paulsenii for which 25% of cells were infected at the station C. The present study shows that dinospores are able to thrive, infects and most probably exert a control on host populations both in coastal and ultra-oligotrophic open waters. Our results emphasize the role of parasitism in microbial food web dynamics and

  11. Influence of host and geographic locale on the distribution of Colletotrichum cereale lineages.

    Directory of Open Access Journals (Sweden)

    Lisa A Beirn

    Full Text Available Colletotrichum cereale is an ascomycete inhabitant of cool-season Pooideae grasses. The fungus has increased in frequency over the past decade as a destructive pathogen of Poa annua and Agrostis stolonifera turfgrass. Colletotrichum cereale exists as two lineages, designated clades A and B, but little is known about the distribution of these clades in natural environments, or what role these subdivisions may play in the trajectory of disease outbreaks. In this study, our objective was to determine the frequency of C. cereale clades A and B. To rapidly discriminate between the two C. cereale clades, a real-time PCR assay was developed based on the Apn2 gene. A collection of 700 C. cereale pathogens and endophytes from twenty Pooideae grass genera were genotyped. 87% of the collection was identifed as part of clade A, 11.7% as part of clade B, and 1.3% was a mixture. Colletotrichum cereale from turfgrass hosts in North America were most commonly members of clade A (78%. The overabundance of clade A in turfgrass isolates was directly attributable to the dominance of this lineage from southern sampling sites, irrespective of host. In contrast, 111 C. cereale turfgrass isolates collected from northern sampling sites were evenly distributed between clades A and B. Only 28% of C. cereale from A. stolonifera at northern sampling sites were part of clade A. These data show that environmental factors such as geographic location and host identity likely played a role in the distribution of the major C. cereale clades in North American turfgrass.

  12. Complete Genome Sequences of Broad-Host-Range Pseudomonas aeruginosa Bacteriophages ΦR18 and ΦS12-1.

    Science.gov (United States)

    Furusawa, Takaaki; Iwano, Hidetomo; Higuchi, Hidetoshi; Usui, Masaru; Maruyama, Fumito; Nakagawa, Ichiro; Yokota, Hiroshi; Tamura, Yutaka

    2016-05-05

    Pseudomonas aeruginosa is an important cause of racehorse keratitis. Bacteriophage therapy has the potential to aid in the prevention and treatment of diseases caused by P. aeruginosa We present here the complete genome sequences of two phages, ΦR18 and ΦS12-1, which exhibit infectivity for a broad range of P. aeruginosa isolates.

  13. Recurrent evolution of host-specialized races in a globally distributed parasite.

    Science.gov (United States)

    McCoy, Karen D; Chapuis, Elodie; Tirard, Claire; Boulinier, Thierry; Michalakis, Yannis; Bohec, Céline Le; Maho, Yvon Le; Gauthier-Clerc, Michel

    2005-11-22

    The outcome of coevolutionary interactions is predicted to vary across landscapes depending on local conditions and levels of gene flow, with some populations evolving more extreme specializations than others. Using a globally distributed parasite of colonial seabirds, the tick Ixodes uriae, we examined how host availability and geographic isolation influences this process. In particular, we sampled ticks from 30 populations of six different seabird host species, three in the Southern Hemisphere and three in the Northern Hemisphere. We show that parasite races have evolved independently on hosts of both hemispheres. Moreover, the degree of differentiation between tick races varied spatially within each region and suggests that the divergence of tick races is an ongoing process that has occurred multiple times across isolated areas. As I. uriae is vector to the bacterium responsible for Lyme disease Borrelia burgdorferi sensu lato, these results may have important consequence for the epidemiology of this disease. With the increased occurrence of novel interspecific interactions due to global change, these results also stress the importance of the combined effects of gene flow and selection for parasite diversification. PMID:16243689

  14. Distributions of quasar hosts on the galaxy main-sequence plane

    CERN Document Server

    Zhang, Zhoujian; Rieke, George H; Xia, Xiaoyang; Wang, Yikang; Sun, Bingqing; Wan, Linfeng

    2016-01-01

    The relation between star formation rates and stellar masses, i.e. the galaxy main sequence, is a useful diagnostic of galaxy evolution. We present the distributions relative to the main sequence of 55 optically-selected PG and 12 near-IR-selected 2MASS quasars at z <= 0.5. We estimate the quasar host stellar masses from Hubble Space Telescope or ground-based AO photometry, and the star formation rates through the mid-infrared aromatic features and far-IR photometry. We find that PG quasar hosts more or less follow the main sequence defined by normal star-forming galaxies while 2MASS quasar hosts lie systematically above the main sequence. PG and 2MASS quasars with higher nuclear luminosities seem to have higher specific SFRs (sSFRs), although there is a large scatter. No trends are seen between sSFRs and SMBH masses, Eddington ratios or even morphology types (ellipticals, spirals and mergers). Our results could be placed in an evolutionary scenario with quasars emerging during the transition from ULIRGs/m...

  15. FTO gene associated fatness in relation to body fat distribution and metabolic traits throughout a broad range of fatness

    DEFF Research Database (Denmark)

    Kring, Sofia I I; Holst, Claus; Zimmermann, Esther;

    2008-01-01

    A common single nucleotide polymorphism (SNP) of FTO (rs9939609, T/A) is associated with total body fatness. We investigated the association of this SNP with abdominal and peripheral fatness and obesity-related metabolic traits in middle-aged men through a broad range of fatness present already...

  16. Seasonal distributions of the western cherry fruit fly (Diptera: Tephritidae) among host and nonhost fruit trees.

    Science.gov (United States)

    Yee, Wee L

    2014-01-01

    Seasonal distributions of the western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), in sweet cherry (Prunus avium (L.) L.) (major host), black hawthorn (occasional developmental host) (Crataegus douglasii Lindley), and other trees were determined in a ponderosa pine ecosystem in Washington state, USA. The hypothesis that most fly dispersal from cherry trees occurs after fruit senesce or drop was tested, with emphasis on movement to black hawthorn trees. Sweet cherry fruit developed earlier than black hawthorn, bitter cherry (common host), choke cherry, and apple fruit. Flies were usually captured first in sweet cherry trees but were caught in bitter cherry and other trees throughout the season. Peak fly capture periods in sweet cherry began around the same time or slightly earlier than in other trees. However, peak fly capture periods in black hawthorn and other nonsweet cherry trees continued after peak periods in sweet cherry ended, or relative fly numbers within sweet cherry declined more quickly than those within other trees. Larvae were reared from sweet and bitter cherry but not black hawthorn fruit. Results provide partial support for the hypothesis in that although R. indifferens commonly disperses from sweet cherry trees with fruit, it could disperse more, or more flies are retained in nonsweet cherry trees after than before sweet cherries drop. This could allow opportunities for the flies to use other fruit for larval development. Although R. indifferens infestation in black hawthorn was not detected, early season fly dispersal to this and other trees and fly presence in bitter cherry could make fly management in sweet cherry difficult.

  17. Seasonal distributions of the western cherry fruit fly (Diptera: Tephritidae) among host and nonhost fruit trees.

    Science.gov (United States)

    Yee, Wee L

    2014-01-01

    Seasonal distributions of the western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), in sweet cherry (Prunus avium (L.) L.) (major host), black hawthorn (occasional developmental host) (Crataegus douglasii Lindley), and other trees were determined in a ponderosa pine ecosystem in Washington state, USA. The hypothesis that most fly dispersal from cherry trees occurs after fruit senesce or drop was tested, with emphasis on movement to black hawthorn trees. Sweet cherry fruit developed earlier than black hawthorn, bitter cherry (common host), choke cherry, and apple fruit. Flies were usually captured first in sweet cherry trees but were caught in bitter cherry and other trees throughout the season. Peak fly capture periods in sweet cherry began around the same time or slightly earlier than in other trees. However, peak fly capture periods in black hawthorn and other nonsweet cherry trees continued after peak periods in sweet cherry ended, or relative fly numbers within sweet cherry declined more quickly than those within other trees. Larvae were reared from sweet and bitter cherry but not black hawthorn fruit. Results provide partial support for the hypothesis in that although R. indifferens commonly disperses from sweet cherry trees with fruit, it could disperse more, or more flies are retained in nonsweet cherry trees after than before sweet cherries drop. This could allow opportunities for the flies to use other fruit for larval development. Although R. indifferens infestation in black hawthorn was not detected, early season fly dispersal to this and other trees and fly presence in bitter cherry could make fly management in sweet cherry difficult. PMID:25527581

  18. Distribution, host plants and natural enemies of sugar beet root aphid (Pemphigus fuscicornis In Slovakia

    Directory of Open Access Journals (Sweden)

    Tóth Peter

    2006-01-01

    Full Text Available During 2003-2004, field surveys were realized to observe the distribution of sugar beet aphid, Pemphigus fuscicornis (K o c h (Sternorrhyncha Pemphigidae in southwestern Slovakia. The research was carried out at 60 different localities with altitudes 112-220 m a. s. l. Sugar beet root aphid was recorded at 30 localities. The aphid was recorded in Slovakia for the first time, but its occurrence was predicted and symptoms and harmfulness overlooked by now. The presence of P. fuscicornis was investigated on roots of various plants from Chenopodiaceae. The most important host plants were various species of lambsquarters (above all Chenopodium album. Furthermore sugar beet (Beta vulgaris provar. altissima, red beet (B. vulgaris provar. conditiva and oraches (Atriplex spp act as host plants. Infestation of sugar beet by P. fuscicornis never exceeded 5% at single locality in Slovakia. Dry and warm weather create presumptions for strong harmfulness. In Slovakia, Chenopodium album is a very important indicator of sugar beet aphid presence allowing evaluation of control requirements. During the study, the larvae of Thaumatomyia glabra (Diptera: Chloropidae were detected as important natural enemies of sugar beet aphid. The species occurred at each location evaluated.

  19. Supernovae and their host galaxies - IV. The distribution of supernovae relative to spiral arms

    CERN Document Server

    Aramyan, L S; Petrosian, A R; de Lapparent, V; Bertin, E; Mamon, G A; Kunth, D; Nazaryan, T A; Adibekyan, V; Turatto, M

    2016-01-01

    Using a sample of 215 supernovae (SNe), we analyze their positions relative to the spiral arms of their host galaxies, distinguishing grand-design (GD) spirals from non-GD (NGD) galaxies. We find that: (1) in GD galaxies, an offset exists between the positions of Ia and core-collapse (CC) SNe relative to the peaks of arms, while in NGD galaxies the positions show no such shifts; (2) in GD galaxies, the positions of CC SNe relative to the peaks of arms are correlated with the radial distance from the galaxy nucleus. Inside (outside) the corotation radius, CC SNe are found closer to the inner (outer) edge. No such correlation is observed for SNe in NGD galaxies nor for SNe Ia in either galaxy class; (3) in GD galaxies, SNe Ibc occur closer to the leading edges of the arms than do SNe II, while in NGD galaxies they are more concentrated towards the peaks of arms. In both samples of hosts, the distributions of SNe Ia relative to the arms have broader wings. These observations suggest that shocks in spiral arms of...

  20. Host-Primed Ebola Virus GP Exposes a Hydrophobic NPC1 Receptor-Binding Pocket, Revealing a Target for Broadly Neutralizing Antibodies

    Science.gov (United States)

    Bornholdt, Zachary A.; Ndungo, Esther; Fusco, Marnie L.; Bale, Shridhar; Flyak, Andrew I.; Crowe, James E.

    2016-01-01

    ABSTRACT The filovirus surface glycoprotein (GP) mediates viral entry into host cells. Following viral internalization into endosomes, GP is cleaved by host cysteine proteases to expose a receptor-binding site (RBS) that is otherwise hidden from immune surveillance. Here, we present the crystal structure of proteolytically cleaved Ebola virus GP to a resolution of 3.3 Å. We use this structure in conjunction with functional analysis of a large panel of pseudotyped viruses bearing mutant GP proteins to map the Ebola virus GP endosomal RBS at molecular resolution. Our studies indicate that binding of GP to its endosomal receptor Niemann-Pick C1 occurs in two distinct stages: the initial electrostatic interactions are followed by specific interactions with a hydrophobic trough that is exposed on the endosomally cleaved GP1 subunit. Finally, we demonstrate that monoclonal antibodies targeting the filovirus RBS neutralize all known filovirus GPs, making this conserved pocket a promising target for the development of panfilovirus therapeutics. PMID:26908579

  1. Sediment-hosted contaminants and distribution patterns in the Mississippi and Atchafalaya River Deltas

    Science.gov (United States)

    Flocks, James G.; Kindinger, Jack G.; Ferina, Nicholas; Dreher, Chandra

    2002-01-01

    The Mississippi and Atchafalaya Rivers transport very large amounts of bedload and suspended sediments to the deltaic and coastal environments of the northern Gulf of Mexico. Absorbed onto these sediments are contaminants that may be detrimental to the environment. To adequately assess the impact of these contaminants it is first necessary to develop an understanding of sediment distribution patterns in these deltaic systems. The distribution patterns are defined by deltaic progradational cycles. Once these patterns are identified, the natural and industrial contaminant inventories and their depositional histories can be reconstructed. Delta progradation is a function of sediment discharge, as well as channel and receiving-basin dimensions. Fluvial energy controls the sediment distribution pattern, resulting in a coarse grained or sandy framework, infilled with finer grained material occupying the overbank, interdistributary bays, wetlands and abandoned channels. It has been shown that these fine-grained sediments can carry contaminants through absorption and intern them in the sediment column or redistribute them depending on progradation or degradation of the delta deposit. Sediment distribution patterns in delta complexes can be determined through high-resolution geophysical surveys and groundtruthed with direct sampling. In the Atchafalaya and Mississippi deltas, remote sensing using High-Resolution Single-Channel Seismic Profiling (HRSP) and Sidescan Sonar was correlated to 20-ft vibracores to develop a near-surface geologic framework that identifies variability in recent sediment distribution patterns. The surveys identified bedload sand waves, abandoned-channel back-fill, prodelta and distributary mouth bars within the most recently active portions of the deltas. These depositional features respond to changes in deltaic processes and through their response may intern or transport absorbed contaminants. Characterizing these features provides insight into the

  2. Supernovae and their host galaxies - IV. The distribution of supernovae relative to spiral arms

    Science.gov (United States)

    Aramyan, L. S.; Hakobyan, A. A.; Petrosian, A. R.; de Lapparent, V.; Bertin, E.; Mamon, G. A.; Kunth, D.; Nazaryan, T. A.; Adibekyan, V.; Turatto, M.

    2016-07-01

    Using a sample of 215 supernovae (SNe), we analyse their positions relative to the spiral arms of their host galaxies, distinguishing grand-design (GD) spirals from non-GD (NGD) galaxies. We find that: (1) in GD galaxies, an offset exists between the positions of Ia and core-collapse (CC) SNe relative to the peaks of arms, while in NGD galaxies the positions show no such shifts; (2) in GD galaxies, the positions of CC SNe relative to the peaks of arms are correlated with the radial distance from the galaxy nucleus. Inside (outside) the corotation radius, CC SNe are found closer to the inner (outer) edge. No such correlation is observed for SNe in NGD galaxies nor for SNe Ia in either galaxy class; (3) in GD galaxies, SNe Ibc occur closer to the leading edges of the arms than do SNe II, while in NGD galaxies they are more concentrated towards the peaks of arms. In both samples of hosts, the distributions of SNe Ia relative to the arms have broader wings. These observations suggest that shocks in spiral arms of GD galaxies trigger star formation in the leading edges of arms affecting the distributions of CC SNe (known to have short-lived progenitors). The closer locations of SNe Ibc versus SNe II relative to the leading edges of the arms supports the belief that SNe Ibc have more massive progenitors. SNe Ia having less massive and older progenitors, have more time to drift away from the leading edge of the spiral arms.

  3. Broad-band spectral energy distribution of 3000 Angstroem break quasars from the Sloan Digital Sky Survey

    CERN Document Server

    Meusinger, H; Mirhosseini, A; Pertermann, F

    2016-01-01

    The Sloan Digital Sky Survey (SDSS) discovered a few unusual quasars with a characteristic break in the continuum around 3000 A that neither shows the typical structure of broad absorption line (BAL) troughs nor is explained by typical intrinsic dust reddening. We used the method of Kohonen self-organising maps for a systematical search for quasars with such properties in the SDSS spectra archive. We constructed a sample of 23 quasars classified as 3000 A break quasars and two comparison samples of quasars with similar properties, to some extent, but also showing typical BAL features. We computed ensemble-averaged broad-band SEDs based on archival data from SDSS, GALEX, 2MASS, UKIDSS, and WISE. The SEDs were corrected for intrinsic dust absorption by the comparison with the average SED of normal quasars. The de-reddened arithmetic median composite SED of the 3000 A break quasars is found to be indistinguishable from that of the unusual BAL quasars. We conclude that 3000 A break quasars are most likely extreme...

  4. Distribution and host diversity of Amoebophryidae parasites across oligotrophic waters of the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    R. Siano

    2011-02-01

    Full Text Available Sequences affiliated to Syndiniales (Marine alveolate, MALV regularly dominate 18S rDNA genetic libraries of nearly all marine ecosystems investigated so far. Among them, Amoebophryidae (MALV group II is composed of numerous and genetically distant environmental sequences, where Amoebophrya is the only known and formally described genus. Amoebophrya species include virulent pathogens for a wide range of dinoflagellate species. Beside their regular occurrence in marine ecosystems, their quantitative distribution and the environmental factors triggering host infection have barely been studied in open oligotrophic waters. In order to understand the functional role of these parasites in natural environments, we studied the distribution and contribution to the eukaryotic community of the small free-living stage of Amoebophryidae (the dinospores along a transect in the Mediterranean Sea, as well as their host diversity at three oligotrophic stations. Dinospores were more abundant at a coastal station (max. 1.5 × 103 cells ml−1 than in oligotrophic waters (max. 51 ± 16.3 cells ml−1, where they represented 10.3 to 34.9% of the total eukaryotic community at 40 and 30 m depth, respectively and 21.2% on average along the water column. Positive correlation was found between dinospore occurrence and higher concentration of NO3 + NO2 at the coastal station. At selected stations, out of 38 different dinoflagellates taxa identified, 15 were infected, among which a majority were not recognized as Amoebophryidae host so far. Prevalences (percentage of infected cells generally varied between 1% and 10%, with a notable exception for Blepharocysta paulsenii for which 25% of cells were infected at the most oligotrophic station. The present study shows that dinospores are able to thrive and infect dinoflagellates both in coastal and ultra-oligotrophic open waters. Our results emphasize

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

    Directory of Open Access Journals (Sweden)

    Mihalca Andrei D

    2012-11-01

    Full Text Available Abstract Background Ticks are among the most important vectors of zoonotic diseases in temperate regions of Europe, with widespread distribution and high densities, posing an important medical risk. Most ticks feed on a variety of progressively larger hosts, with a large number of small mammal species typically harbouring primarily the immature stages. However, there are certain Ixodidae that characteristically attack micromammals also during their adult stage. Rodents are widespread hosts of ticks, important vectors and competent reservoirs of tick-borne pathogens. Micromammal-tick associations have been poorly studied in Romania, and our manuscript shows the results of a large scale study on tick infestation epidemiology in rodents from Romania. Methods Rodents were caught using snap-traps in a variety of habitats in Romania, between May 2010 and November 2011. Ticks were individually collected from these rodents and identified to species and development stage. Frequency, mean intensity, prevalence and its 95% confidence intervals were calculated using the EpiInfo 2000 software. A p value of Results We examined 423 rodents (12 species collected from six counties in Romania for the presence of ticks. Each collected tick was identified to species level and the following epidemiological parameters were calculated: prevalence, mean intensity and mean abundance. The total number of ticks collected from rodents was 483, with eight species identified: Ixodes ricinus, I. redikorzevi, I. apronophorus, I. trianguliceps, I. laguri, Dermacentor marginatus, Rhipicephalus sanguineus and Haemaphysalis sulcata. The overall prevalence of tick infestation was 29.55%, with a mean intensity of 3.86 and a mean abundance of 1.14. Only two polyspecific infestations were found: I. ricinus + I. redikorzevi and I. ricinus + D. marginatus. Conclusions Our study showed a relatively high diversity of ticks parasitizing rodents in Romania. The most common tick in rodents

  6. LONG GRBs ARE METALLICITY-BIASED TRACERS OF STAR FORMATION: EVIDENCE FROM HOST GALAXIES AND REDSHIFT DISTRIBUTION

    Energy Technology Data Exchange (ETDEWEB)

    Wang, F. Y.; Dai, Z. G., E-mail: fayinwang@nju.edu.cn, E-mail: dzg@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)

    2014-07-01

    We investigate the mass distribution of long gamma-ray burst (GRB) host galaxies and the redshift distribution of long GRBs by considering that long GRBs occur in low-metallicity environments. We calculate the upper limit on the stellar mass of a galaxy which can produce long GRBs by utilizing the mass-metallicity (M-Z) relation of galaxies. After comparing with the observed GRB host galaxies masses, we find that the observed GRB host galaxy masses can fit the predicted masses well if GRBs occur in low-metallicity 12 + log (O/H){sub KK04} < 8.7. GRB host galaxies have low metallicity, low mass, and high star formation rate compared with galaxies of seventh data release of the Sloan Digital Sky Survey. We also study the cumulative redshift distribution of the latest Swift long GRBs by adding dark GRBs and 10 new GRBs redshifts from the TOUGH survey. The observed discrepancy between the GRB rate and the star formation history can be reconciled by considering that GRBs tend to occur in low-metallicity galaxies with 12 + log (O/H){sub KK04} < 8.7. We conclude that the metallicity cutoff that can produce long GRBs is about 12 + log (O/H){sub KK04} < 8.7 from the host mass distribution and redshift distribution.

  7. Schistosomes with wings: how host phylogeny and ecology shape the global distribution of Trichobilharzia querquedulae (Schistosomatidae).

    Science.gov (United States)

    Ebbs, Erika T; Loker, Eric S; Davis, Norm E; Flores, Veronica; Veleizan, Aylen; Brant, Sara V

    2016-09-01

    Migratory waterfowl play an important role in the maintenance and spread of zoonotic diseases worldwide. An example is cercarial dermatitis, caused when larval stages of schistosomes that normally develop in birds penetrate human skin. Members of the genus Trichobilharzia (Schistosomatidae), transmitted mainly by ducks, are considered to be major etiological agents of cercarial dermatitis globally. To better understand the diversity and distribution of Trichobilharzia spp., we surveyed ducks from the United States, eastern Canada, Argentina, South Africa and New Zealand. To aid in species identification of the Trichobilharzia worms recovered, regions of the Cox1, ND4 and ITS1 were sequenced. Furthermore, we provide molecular phylogenetic evidence for the cosmopolitan distribution and trans-hemispheric gene flow for one species, Trichobilharzia querquedulae, previously thought to be restricted to North America. These new samples from endemic non-migratory duck species indicate that T. querquedulae transmission occurs within each of the regions we sampled and that it is specific to the blue-winged+silver teal duck clade. Prevalence within this host group is >95% across the known range of T. querquedulae, indicating that transmission is common. Genetic divergence is evenly distributed among continents, and no phylogenetic structure associated with geography was observed. The results provide strong support for the global distribution and transmission of T. querquedulae and represent, to our knowledge, the first report of a cosmopolitan schistosome confirmed by genetic data. These data are the first known to support trans-hemispheric genetic exchange in a species responsible for causing cercarial dermatitis, indicating that the epidemiology of this group of poorly known zoonotic parasites is more complex than previously expected. PMID:27260861

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

    Directory of Open Access Journals (Sweden)

    Nathan P Lemoine

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

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

    Science.gov (United States)

    Lemoine, Nathan P

    2015-01-01

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

  10. New evidence on a cold case: trophic transmission, distribution and host-specificity in Hedruris spinigera (Nematoda: Hedruridae).

    Science.gov (United States)

    Luque, José L; Vieira, Fabiano M; Herrmann, Kristin; King, Tania M; Poulin, Robert; Lagrue, Clément

    2010-09-01

    The life cycle of Hedruris spinigera Baylis, 1931 (Nematoda: Hedruridae) is determined here with the first formal identification of the parasite's intermediate host: the crustacean amphipod Paracorophium excavatum Thomson. Adult H. spinigera are redescribed from specimens collected from the stomach of fishes, Retropinna retropinna (Richardson) and Aldrichettaforsteri (Valenciennes), from Lake Waihola, New Zealand. Immature adults of the parasite collected from intermediate hosts (P. excavatum) are also described for the first time. The prevalence, abundance and intensity of infection of H. spinigera in several fish species are quantified along with the occurrence of P. excavatum, the parasite's intermediate host, in fish stomach contents. Although H. spinigera's transmission mode (trophic transmission) and fish diet potentially expose all fish species to infection, some level of host specificity must exist as parasite prevalence, abundance and intensity of infection vary greatly between potential definitive host species. We suggest here that the anatomy of the fish digestive tract and especially that of the stomach plays an important role in host suitability for H. spinigera. While P. excavatum is the only intermediate host in Lake Waihola, H. spinigera was found in six different fish species: Aldrichetta forsteri, Galaxias maculatus (Jenyns), Retropinna retropinna, Rhombosolea retiaria Hutton, Perca fluviatilis Linnaeus and Salmo trutta Linnaeus; although typical hedrurid attachment and mating positions were observed only in R. retropinna and A. forsteri. The limited distribution of H. spinigera is most likely due to that of its different host species (intermediate and definitive), all inhabitants of coastal fresh and brackish waters. PMID:20941914

  11. Winged Pea Aphids Can Modify Phototaxis in Different Development Stages to Assist Their Host Distribution.

    Science.gov (United States)

    Zhang, Yi; Wang, Xing-Xing; Jing, Xiangfeng; Tian, Hong-Gang; Liu, Tong-Xian

    2016-01-01

    The pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), shows wing polyphenism (winged and wingless morphs) in its life cycle. The winged morph is adapted for dispersal; its two developmental adult stages (for dispersal and reproduction) are based on its breeding periods. The two morphs show different phototactic behavior and the winged can change its preference to light according to the developmental stages. To determine the mechanism and ecological functions of phototaxis for A. pisum, we first investigated the phototaxis of the two aphid morphs at different stages and analyzed the phototactic response to lights of different wavelengths; the correlation between alate fecundity and their phototactic behaviors were then studied. Finally, we focused on the possible functions of phototaxis in aphid host location and distribution in combination with gravitaxis behaviors. Negative phototaxis was found for breeding winged adults but all the other stages of both winged and wingless morphs showed positive phototaxis. The reactions of the aphids to different wavelengths were also different. Nymph production in winged adults showed negative correlation to phototaxis. The dopamine pathway was possibly involved in these behavior modifications. We speculated that winged adults can use light for dispersal in the early dispersal stage and for position holding in the breeding stage. Based on our results, we assume that light signals are important for aphid dispersal and distribution, and are also essential for the pea aphids to cope with environmental changes. PMID:27531980

  12. Environmental Correlates of Distribution of the 25 Broad-leaved Tree Species Indigenous to Guangdong Province, China

    Institute of Scientific and Technical Information of China (English)

    Su Zhiyao; Chen Beiguang; Chang Yong; Yang Jiazhi

    2004-01-01

    Twenty-five tree species indigenous to Guangdong Province were chosen in this study to portray their distribution patterns in relation to environmental factors. Both data of species distribution and environmental factors were tabulated based on a digitized map of Guangdong Province gridded at 0.5° latitude × 0.5° longitude. Grid-based diversity was mapped using DMAP, a distribution mapping program, and horizontal patterns were assessed using Kruskal-Wallis tests. The diversity center of the indigenous tree species under study is located north of 23° N. These tree species exhibit significant latitudinal variation (P = 0.007 4), but no significant longitudinal difference (P = 0.052 2). Non-metric Multidimensional Scaling (NMS) identified five different ecological species groups, while Canonical Correspondence Analysis (CCA) showed the distribution of tree species along each of the five environmental gradients. An understanding of the environmental correlates of distribution patterns has great implication for the introduction of the indigenous tree species for afforestation.

  13. Colonization of Barley by the Broad-Host Hemibiotrophic Pathogen Phytophthora palmivora Uncovers a Leaf Development-Dependent Involvement of Mlo.

    Science.gov (United States)

    Le Fevre, Ruth; O'Boyle, Bridget; Moscou, Matthew J; Schornack, Sebastian

    2016-05-01

    The discovery of barley Mlo demonstrated that filamentous pathogens rely on plant genes to achieve entry and lifecycle completion in barley leaves. While having a dramatic effect on foliar pathogens, it is unclear whether overlapping or distinct mechanisms affect filamentous pathogen infection of roots. To remove the bias connected with using different pathogens to understand colonization mechanisms in different tissues, we have utilized the aggressive hemibiotrophic oomycete pathogen Phytophthora palmivora. P. palmivora colonizes root as well as leaf tissues of barley (Hordeum vulgare). The infection is characterized by a transient biotrophy phase with formation of haustoria. Barley accessions varied in degree of susceptibility, with some accessions fully resistant to leaf infection. Notably, there was no overall correlation between degree of susceptibility in roots compared with leaves, suggesting that variation in different genes influences host susceptibility above and below ground. In addition, a developmental gradient influenced infection, with more extensive colonization observed in mature leaf sectors. The mlo5 mutation attenuates P. palmivora infection but only in young leaf tissues. The barley-P. palmivora interaction represents a simple system to identify and compare genetic components governing quantitative colonization in diverse barley tissue types.

  14. Diversity and Distribution of Host Animal Species of Hantavirus and Risk to Human Health in Jiuhua Mountain Area, China

    Institute of Scientific and Technical Information of China (English)

    HU Xing Qiang; LI Shi Guang; LIU Hong; WANG Jun; HUA Ri Mao

    2014-01-01

    Objective To investigate the diversity and the distribution of host animal species of hantavirus and the effect on human health in Jiuhua Mountain area, China. Methods The host animal species of hantavirus was surveyed by using the trap method and the species diversity was evaluated by using the Simpson, Shannon-Weaner, and Pielou indices. Hantavirus antigens or antibodies in lung and blood samples of all the captured host animals were detected by direct or indirect immunofluorescence. Results Nine animal species of hantavirus were distributed in the forest ecosystem of Jiuhua Mountain. Of these, Niviventer confucianus and Apodemus agrarius were predominant, and N. confucianus, Rattus norvegicus, and Mus musculus had relatively large niche breadth index values. The host animals in the eastern and western mountain regions shared similar biodiversity index characteristics, predominant species, and species structures. Hantavirus was detected in 5 host animal species in Jiuhua Mountain area, the carriage rate of hantavirus was 6.03%. The average density of host animals in forest areas of the mountainous area was only 2.20%, and the virus infection rate in the healthy population was 2.33%. Conclusion The circulation of hantavirus was low in the forest areas of Jiuhua Mountain and did not pose a threat to human health.

  15. Additions to the Encyrtidae and Mymaridae (Chalcidoidea) of India with new distribution and host records for some species

    Science.gov (United States)

    Rameshkumar, A.; V, Naveen

    2015-01-01

    Abstract Background Encyrtidae and Mymaridae of India have not been surveyed in depth and hosts are not known for most of the species as the methods of collections used are passive and do not yield firsthand information on the hosts. Based on our ongoing surveys on the Encyrtidae and Mymaridae of India, we report here new distribution and host records for some species. New information Acmopolynema campylurum Xu and Lin, Litus cynipseus Haliday, Omyomymar glabrum Lin and Chiappini and Platystethynium Ogloblin (Mymaridae), and Rhytidothorax purpureiscutellum (Girault) (Encyrtidae) are reported for the first time from India. Anagyrus aquilonaris (Noyes and Hayat) is recorded as new to Arunachal Pradesh and Meghalaya. Paraphaenodiscus indicus Singh and Agarwal and Paraphaenodiscus monawari Bhuiya are recorded from south India for the first time, the latter on a new host, Pulvinaria polygonata. Chorizococcus sorghi Williams (Pseudococcidae) is reported as a host for Cryptanusia ajmerensis (Fatma & Shafee), for which no hosts are hitherto known and the male of Cryptanusia is documented for the first time. Aclerda sp. is recorded as a new host for Neastymachus axillaris Singh, Agarwal and Basha. PMID:26069438

  16. Grapes, galls, and geography: the distribution of nuclear and mitochondrial DNA variation across host-plant species and regions in a specialist herbivore.

    Science.gov (United States)

    Downie, D A; Fisher, J R; Granett, J

    2001-07-01

    Studies of patterns of molecular variation in natural populations can provide important insights into a number of evolutionary problems. Among these, the question of whether geographic factors are more important than ecological factors in promoting population differentiation and ultimately speciation has been an important and contentious area in evolutionary biology. Systems involving herbivorous insects have played a leading role in this discussion. This study examined the distribution of molecular variation in a highly specialized gall-forming insect, grape phylloxera (Daktulosphaira vitifoliae Fitch), that is found on both sympatric and allopatric host-plant species of the genus Vitis. In addition, the relationship of insects in the introduced range in the United States to ancestral populations in the native range was examined. Evidence for differentiation along host-plant lines from both nuclear (RAPD) and mitochondrial (COI) DNA was confounded with the effect of geography. Differentiation was found where hosts were allopatric or parapatric, but no evidence was found for such differentiation on two hosts, V. vulpina and V. aestivalis, that are broadly sympatric. The question of population differentiation onto these sympatric hosts can be considered to be resolved--it has not occurred in spite of a long history of association. Evidence was equivocal, but suggestive of a period of divergence in allopatry prior to reestablishment of contact, for insects associated with another host plant species, V. cinerea, found in both sympatric and parapatric populations. A low level of diversity and placement of samples collected from the grape species V. riparia at the tip of a phylogenetic tree supports the hypothesis that this host has been recently colonized from populations from the Mississippi Valley. A polyphyletic origin for biotype B grape phylloxera was supported: Although most samples collected from vineyards in the introduced range in California had similar

  17. Abundance and Relative Distribution of Frankia Host Infection Groups Under Actinorhizal Alnus glutinosa and Non-actinorhizal Betula nigra Trees.

    Science.gov (United States)

    Samant, Suvidha; Huo, Tian; Dawson, Jeffrey O; Hahn, Dittmar

    2016-02-01

    Quantitative polymerase chain reaction (qPCR) was used to assess the abundance and relative distribution of host infection groups of the root-nodule forming, nitrogen-fixing actinomycete Frankia in four soils with similar physicochemical characteristics, two of which were vegetated with a host plant, Alnus glutinosa, and two with a non-host plant, Betula nigra. Analyses of DAPI-stained cells at three locations, i.e., at a distance of less than 1 m (near stem), 2.5 m (middle crown), and 3-5 m (crown edge) from the stems of both tree species revealed no statistically significant differences in abundance. Frankiae generally accounted for 0.01 to 0.04 % of these cells, with values between 4 and 36 × 10(5) cells (g soil)(-1). In three out of four soils, abundance of frankiae was significantly higher at locations "near stem" and/or "middle crown" compared to "crown edge," while numbers at these locations were not different in the fourth soil. Frankiae of the Alnus host infection group were dominant in all samples accounting for about 75 % and more of the cells, with no obvious differences with distance to stem. In three of the soils, all of these cells were represented by strain Ag45/Mut15. In the fourth soil that was vegetated with older A. glutinosa trees, about half of these cells belonged to a different subgroup represented by strain ArI3. In all soils, the remaining cells belonged to the Elaeagnus host infection group represented by strain EAN1pec. Casuarina-infective frankiae were not found. Abundance and relative distribution of Frankia host infection groups were similar in soils under the host plant A. glutinosa and the non-host plant B. nigra. Results did thus not reveal any specific effects of plant species on soil Frankia populations.

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

    Directory of Open Access Journals (Sweden)

    K.N. De Kock

    2005-09-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  20. Genomic basis of broad host range and environmental adaptability of Rhizobium tropici CIAT 899 and Rhizobium sp. PRF 81 which are used in inoculants for common bean (Phaseolus vulgaris L.

    Directory of Open Access Journals (Sweden)

    Ormeño-Orrillo Ernesto

    2012-12-01

    Full Text Available Abstract Background Rhizobium tropici CIAT 899 and Rhizobium sp. PRF 81 are α-Proteobacteria that establish nitrogen-fixing symbioses with a range of legume hosts. These strains are broadly used in commercial inoculants for application to common bean (Phaseolus vulgaris in South America and Africa. Both strains display intrinsic resistance to several abiotic stressful conditions such as low soil pH and high temperatures, which are common in tropical environments, and to several antimicrobials, including pesticides. The genetic determinants of these interesting characteristics remain largely unknown. Results Genome sequencing revealed that CIAT 899 and PRF 81 share a highly-conserved symbiotic plasmid (pSym that is present also in Rhizobium leucaenae CFN 299, a rhizobium displaying a similar host range. This pSym seems to have arisen by a co-integration event between two replicons. Remarkably, three distinct nodA genes were found in the pSym, a characteristic that may contribute to the broad host range of these rhizobia. Genes for biosynthesis and modulation of plant-hormone levels were also identified in the pSym. Analysis of genes involved in stress response showed that CIAT 899 and PRF 81 are well equipped to cope with low pH, high temperatures and also with oxidative and osmotic stresses. Interestingly, the genomes of CIAT 899 and PRF 81 had large numbers of genes encoding drug-efflux systems, which may explain their high resistance to antimicrobials. Genome analysis also revealed a wide array of traits that may allow these strains to be successful rhizosphere colonizers, including surface polysaccharides, uptake transporters and catabolic enzymes for nutrients, diverse iron-acquisition systems, cell wall-degrading enzymes, type I and IV pili, and novel T1SS and T5SS secreted adhesins. Conclusions Availability of the complete genome sequences of CIAT 899 and PRF 81 may be exploited in further efforts to understand the interaction of tropical

  1. The Swift Gamma-Ray Burst Host Galaxy Legacy Survey - I. Sample Selection and Redshift Distribution

    OpenAIRE

    Perley, D. A.; Krühler, T.; Schulze, S.; De Ugarte Postigo, A.; Hjorth, J.; Berger, E.; Cenko, S. B.; Chary, R.; Cucchiara, A.; Ellis, R; Fong, W.; Fynbo, J. P. U.; J. Gorosabel; Greiner, J.; Jakobsson, P.

    2015-01-01

    We introduce the Swift Gamma-Ray Burst Host Galaxy Legacy Survey ("SHOALS"), a multi-observatory high-redshift galaxy survey targeting the largest unbiased sample of long-duration gamma-ray burst (GRB) hosts yet assembled (119 in total). We describe the motivations of the survey and the development of our selection criteria, including an assessment of the impact of various observability metrics on the success rate of afterglow-based redshift measurement. We briefly outline our host galaxy obs...

  2. Bacillus cereus Biovar Anthracis Causing Anthrax in Sub-Saharan Africa—Chromosomal Monophyly and Broad Geographic Distribution

    Science.gov (United States)

    Mabon, Philip; Zimmermann, Fee; Lankester, Felix; Peller, Tianna; Feistner, Anna; Todd, Angelique; Herbinger, Ilka; de Nys, Hélène M.; Muyembe-Tamfun, Jean-Jacques; Karhemere, Stomy; Wittig, Roman M.; Couacy-Hymann, Emmanuel; Grunow, Roland; Calvignac-Spencer, Sébastien; Corbett, Cindi R.; Klee, Silke R.; Leendertz, Fabian H.

    2016-01-01

    Through full genome analyses of four atypical Bacillus cereus isolates, designated B. cereus biovar anthracis, we describe a distinct clade within the B. cereus group that presents with anthrax-like disease, carrying virulence plasmids similar to those of classic Bacillus anthracis. We have isolated members of this clade from different mammals (wild chimpanzees, gorillas, an elephant and goats) in West and Central Africa (Côte d’Ivoire, Cameroon, Central African Republic and Democratic Republic of Congo). The isolates shared several phenotypic features of both B. anthracis and B. cereus, but differed amongst each other in motility and their resistance or sensitivity to penicillin. They all possessed the same mutation in the regulator gene plcR, different from the one found in B. anthracis, and in addition, carry genes which enable them to produce a second capsule composed of hyaluronic acid. Our findings show the existence of a discrete clade of the B. cereus group capable of causing anthrax-like disease, found in areas of high biodiversity, which are possibly also the origin of the worldwide distributed B. anthracis. Establishing the impact of these pathogenic bacteria on threatened wildlife species will require systematic investigation. Furthermore, the consumption of wildlife found dead by the local population and presence in a domestic animal reveal potential sources of exposure to humans. PMID:27607836

  3. Prediction of SAMPL3 Host-Guest Affinities with the Binding Energy Distribution Analysis Method (BEDAM)

    OpenAIRE

    Gallicchio, Emilio; Ronald M Levy

    2012-01-01

    BEDAM calculations are described to predict the free energies of binding of a series of anaesthetic drugs to a recently characterized acyclic cucurbituril host. The modeling predictions, conducted as part of the SAMPL3 host-guest affinity blind challenge, are generally in good quantitative agreement with the experimental measurements. The correlation coefficient between computed and measured binding free energies is 70% with high statistical significance. Multiple conformational stereoisomers...

  4. Estimating the Sunyaev - Zel'dovich signal from quasar hosts using a Halo Occupation Distribution based approach

    CERN Document Server

    Chowdhury, Dhruba Dutta

    2015-01-01

    The Sunyaev-Zeldovich (SZ) effect is a spectral distortion in the Cosmic Microwave Background (CMB), caused due to up-scattering of CMB photons by high energy electron distributions. The largest SZ distortion in the CMB is caused by the hot electrons present in the intra-cluster medium (ICM). However, several other small scale astrophysical processes can also contribute to the SZ distortion in the CMB. Analytic studies have shown that the interstellar (ISM) electron gas of the host galaxy heated by quasar feedback can also cause substantial SZ effect. For successful detection of the quasar feedback signal, the SZ signal from the virialized gas in the host halos of quasars needs to be properly quantified. In this dissertation work, I have estimated the SZ signal from quasar hosts using analytic models of the virialized gas in the ICM/ISM. As a new extension to existing work I have used the measured Halo Occupation Distribution properties of quasar hosts. The results show that the average SZ signal from quasar ...

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

    OpenAIRE

    Nathan P Lemoine

    2015-01-01

    Climate change can profoundly alter species’ distributions due to changes in temperature, precipitation, or seasonality. Migratory monarch butterflies (Danaus plexippus) may be particularly susceptible to climate-driven changes in host plant abundance or reduced overwintering habitat. For example, climate change may significantly reduce the availability of overwintering habitat by restricting the amount of area with suitable microclimate conditions. However, potential effects of climate chang...

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

    KAUST Repository

    Miyake, Sou

    2016-03-14

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

  7. Environmental variables and definitive host distribution: a habitat suitability modelling for endohelminth parasites in the marine realm

    Science.gov (United States)

    Kuhn, Thomas; Cunze, Sarah; Kochmann, Judith; Klimpel, Sven

    2016-08-01

    Marine nematodes of the genus Anisakis are common parasites of a wide range of aquatic organisms. Public interest is primarily based on their importance as zoonotic agents of the human Anisakiasis, a severe infection of the gastro-intestinal tract as result of consuming live larvae in insufficiently cooked fish dishes. The diverse nature of external impacts unequally influencing larval and adult stages of marine endohelminth parasites requires the consideration of both abiotic and biotic factors. Whereas abiotic factors are generally more relevant for early life stages and might also be linked to intermediate hosts, definitive hosts are indispensable for a parasite’s reproduction. In order to better understand the uneven occurrence of parasites in fish species, we here use the maximum entropy approach (Maxent) to model the habitat suitability for nine Anisakis species accounting for abiotic parameters as well as biotic data (definitive hosts). The modelled habitat suitability reflects the observed distribution quite well for all Anisakis species, however, in some cases, habitat suitability exceeded the known geographical distribution, suggesting a wider distribution than presently recorded. We suggest that integrative modelling combining abiotic and biotic parameters is a valid approach for habitat suitability assessments of Anisakis, and potentially other marine parasite species.

  8. Environmental variables and definitive host distribution: a habitat suitability modelling for endohelminth parasites in the marine realm

    Science.gov (United States)

    Kuhn, Thomas; Cunze, Sarah; Kochmann, Judith; Klimpel, Sven

    2016-01-01

    Marine nematodes of the genus Anisakis are common parasites of a wide range of aquatic organisms. Public interest is primarily based on their importance as zoonotic agents of the human Anisakiasis, a severe infection of the gastro-intestinal tract as result of consuming live larvae in insufficiently cooked fish dishes. The diverse nature of external impacts unequally influencing larval and adult stages of marine endohelminth parasites requires the consideration of both abiotic and biotic factors. Whereas abiotic factors are generally more relevant for early life stages and might also be linked to intermediate hosts, definitive hosts are indispensable for a parasite’s reproduction. In order to better understand the uneven occurrence of parasites in fish species, we here use the maximum entropy approach (Maxent) to model the habitat suitability for nine Anisakis species accounting for abiotic parameters as well as biotic data (definitive hosts). The modelled habitat suitability reflects the observed distribution quite well for all Anisakis species, however, in some cases, habitat suitability exceeded the known geographical distribution, suggesting a wider distribution than presently recorded. We suggest that integrative modelling combining abiotic and biotic parameters is a valid approach for habitat suitability assessments of Anisakis, and potentially other marine parasite species. PMID:27507328

  9. Distribution of multilocus genotypes of Escherichia coli within and between host families.

    Science.gov (United States)

    Caugant, D A; Levin, B R; Selander, R K

    1984-06-01

    Isolates from the intestinal Escherichia coli flora of 28 members of five families (including parents, children, and household pets) in Amherst, Massachusetts, and Rochester, New York, were characterized by the electrophoretic mobilities of 12 enzymes to estimate the extent of sharing of strains among associated and unassociated hosts. Among the 655 isolates examined, 60 different combinations of electromorphs (electrophoretic types or ETs), each representing a distinctive multilocus genotype, were identified, of which 85% were recovered from only a single individual. On average, 11% of the ETs isolated from the same family were shared by two or more members; 4.9% of ETs were shared among members of unassociated families living in the same city; and only 2% were shared by families in different cities. All three ETs that were recovered from multiple hosts in the present study are widespread clones that have been isolated from many other host individuals in North America and Sweden. PMID:6376625

  10. The Swift Gamma-Ray Burst Host Galaxy Legacy Survey. I. Sample Selection and Redshift Distribution

    Science.gov (United States)

    Perley, D. A.; Krühler, T.; Schulze, S.; de Ugarte Postigo, A.; Hjorth, J.; Berger, E.; Cenko, S. B.; Chary, R.; Cucchiara, A.; Ellis, R.; Fong, W.; Fynbo, J. P. U.; Gorosabel, J.; Greiner, J.; Jakobsson, P.; Kim, S.; Laskar, T.; Levan, A. J.; Michałowski, M. J.; Milvang-Jensen, B.; Tanvir, N. R.; Thöne, C. C.; Wiersema, K.

    2016-01-01

    We introduce the Swift Gamma-Ray Burst Host Galaxy Legacy Survey (“SHOALS”), a multi-observatory high-redshift galaxy survey targeting the largest unbiased sample of long-duration gamma-ray burst (GRB) hosts yet assembled (119 in total). We describe the motivations of the survey and the development of our selection criteria, including an assessment of the impact of various observability metrics on the success rate of afterglow-based redshift measurement. We briefly outline our host galaxy observational program, consisting of deep Spitzer/IRAC imaging of every field supplemented by similarly deep, multicolor optical/near-IR photometry, plus spectroscopy of events without preexisting redshifts. Our optimized selection cuts combined with host galaxy follow-up have so far enabled redshift measurements for 110 targets (92%) and placed upper limits on all but one of the remainder. About 20% of GRBs in the sample are heavily dust obscured, and at most 2% originate from z\\gt 5.5. Using this sample, we estimate the redshift-dependent GRB rate density, showing it to peak at z∼ 2.5 and fall by at least an order of magnitude toward low (z = 0) redshift, while declining more gradually toward high (z∼ 7) redshift. This behavior is consistent with a progenitor whose formation efficiency varies modestly over cosmic history. Our survey will permit the most detailed examination to date of the connection between the GRB host population and general star-forming galaxies, directly measure evolution in the host population over cosmic time and discern its causes, and provide new constraints on the fraction of cosmic star formation occurring in undetectable galaxies at all redshifts.

  11. Distribution of Serotypes and Antimicrobial Resistance Genes among Streptococcus agalactiae Isolates from Bovine and Human Hosts

    OpenAIRE

    Dogan, Belgin; Schukken, Y. H.; de Santisteban, C.; Boor, Kathryn J.

    2005-01-01

    To better understand the emergence and transmission of antibiotic-resistant Streptococcus agalactiae, we compared phenotypic and genotypic characteristics of 52 human and 83 bovine S. agalactiae isolates. Serotypes found among isolates from human hosts included V (48.1%), III (19.2%), Ia and Ib (13.5% each), and II (5.8%). Among isolates from bovine hosts, molecular serotypes III and II were predominant (53 and 14.5%, respectively). Four and 21 different ribotypes were found among human and b...

  12. The Swift Gamma-Ray Burst Host Galaxy Legacy Survey - I. Sample Selection and Redshift Distribution

    CERN Document Server

    Perley, D A; Schulze, S; Postigo, A de Ugarte; Hjorth, J; Berger, E; Cenko, S B; Chary, R; Cucchiara, A; Ellis, R; Fong, W; Fynbo, J P U; Gorosabel, J; Greiner, J; Jakobsson, P; Laskar, T; Levan, A J; Michałowski, M J; Milvang-Jensen, B; Tanvir, N R; Thöne, C C; Wiersema, K

    2016-01-01

    We introduce the Swift Gamma-Ray Burst Host Galaxy Legacy Survey ("SHOALS"), a multi-observatory high-redshift galaxy survey targeting the largest unbiased sample of long-duration gamma-ray burst hosts yet assembled (119 in total). We describe the motivations of the survey and the development of our selection criteria, including an assessment of the impact of various observability metrics on the success rate of afterglow-based redshift measurement. We briefly outline our host-galaxy observational program, consisting of deep Spitzer/IRAC imaging of every field supplemented by similarly-deep, multi-color optical/NIR photometry, plus spectroscopy of events without pre-existing redshifts. Our optimized selection cuts combined with host-galaxy follow-up have so far enabled redshift measurements for 110 targets (92%) and placed upper limits on all but one of the remainder. About 20% of GRBs in the sample are heavily dust-obscured, and at most 2% originate from z>5.5. Using this sample we estimate the redshift-depen...

  13. Is the nestedness of metazoan parasite assemblages of marine fishes from the southeastern Pacific coast a pattern associated with the geographical distributional range of the host?

    Science.gov (United States)

    González, M T; Oliva, M E

    2009-04-01

    Nested structure is a pattern originally described in island biogeography to characterize how a set of species is distributed among a set of islands. In parasite communities, nestedness has been intensively studied among individual fish from a locality. However, nested patterns among parasite assemblages from different host populations (localities) have scarcely been investigated. We recorded the occurrence of parasites in 9 fish species widely distributed along the southeastern Pacific coast to determine whether the ecto- and endoparasite assemblages of marine fishes show a nested structure associated with host distributional range. Nestedness was tested using Brualdi-Sanderson index of discrepancy (BR); and 5 null models incorporated in a 'Nestedness' programme (Ulrich, 2006). The ecto- and endoparasite richness do not show similar patterns of latitudinal gradients among fish hosts, with 33-66% of analysed ectoparasite assemblages, and 25-75% of endoparasite assemblages showing nested structures through the host distributional range. For ectoparasites, species richness gradients and nested structure (when present) might be associated with decreased host densities or could reflect negative environmental conditions in the distributional border of the host species, whereas for endoparasites might be caused by geographical breaks of prey or changes in prey availability (intermediate hosts). The sampled extension of the distributional range of the host species, as well as the lack of specificity of some parasites, could influence the detection of nestedness. PMID:19195414

  14. Fine-tuning the space, time, and host distribution of mycobacteria in wildlife

    Directory of Open Access Journals (Sweden)

    de la Fuente Jose

    2011-02-01

    Full Text Available Abstract Background We describe the diversity of two kinds of mycobacteria isolates, environmental mycobacteria and Mycobacterium bovis collected from wild boar, fallow deer, red deer and cattle in Doñana National Park (DNP, Spain, analyzing their association with temporal, spatial and environmental factors. Results High diversity of environmental mycobacteria species and M. bovis typing patterns (TPs were found. When assessing the factors underlying the presence of the most common types of both environmental mycobacteria and M. bovis TPs in DNP, we evidenced (i host species differences in the occurrence, (ii spatial structuration and (iii differences in the degree of spatial association of specific types between host species. Co-infection of a single host by two M. bovis TPs occurred in all three wild ungulate species. In wild boar and red deer, isolation of one group of mycobacteria occurred more frequently in individuals not infected by the other group. While only three TPs were detected in wildlife between 1998 and 2003, up to 8 different ones were found during 2006-2007. The opposite was observed in cattle. Belonging to an M. bovis-infected social group was a significant risk factor for mycobacterial infection in red deer and wild boar, but not for fallow deer. M. bovis TPs were usually found closer to water marshland than MOTT. Conclusions The diversity of mycobacteria described herein is indicative of multiple introduction events and a complex multi-host and multi-pathogen epidemiology in DNP. Significant changes in the mycobacterial isolate community may have taken place, even in a short time period (1998 to 2007. Aspects of host social organization should be taken into account in wildlife epidemiology. Wildlife in DNP is frequently exposed to different species of non-tuberculous, environmental mycobacteria, which could interact with the immune response to pathogenic mycobacteria, although the effects are unknown. This research

  15. A study of the early detection of insect infestations and density/distribution of host plants

    Science.gov (United States)

    Hart, W. G.; Ingle, S. J.; Davis, M. R. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. Significant results have been obtained in the identification of citrus, sugarcane, winter vegetables, irrigated pastures, and unimproved pastures which contain brush. Land without vegetation, lakes, roads, and waterways can also be determined. Different densities of vegetation covering some cultivated areas are apparent. The practical applications of these results are many. The abundance of host plants of pests can be determined. Avenues of entry of pests can be plotted, facilitating control or preventing entry of pest species. The boundaries of areas to be quarantined can be accurately established after viewing the S-190B data. Better cultural methods can be employed such as planning where to plant certain crops that indirectly are detrimental to those already growing. This would relate to such factors as pesticide drift or alternate hosts of major pests.

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

    Directory of Open Access Journals (Sweden)

    Veronica Andreo

    2014-01-01

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

  17. The role of geography and host abundance in the distribution of parasitoids of an alien pest

    OpenAIRE

    Nováková, Petra; Holuša, Jaroslav; Horák, Jakub

    2016-01-01

    Chalcid wasps (Hymenoptera: Chalcidoidea) are probably the most effective and abundant parasitoids of the horse chestnut leaf miner (Cameraria ohridella), an alien pest in Europe that lacks specialized enemies. We studied how the species richness and abundance of chalcids are influenced by altitude, direction of an alien spread and host abundance of C. ohridella. We quantified the numbers and species richness of chalcid wasps and the numbers of C. ohridella that emerged from horse chestnut (A...

  18. Distribution of multilocus genotypes of Escherichia coli within and between host families.

    OpenAIRE

    Caugant, D A; Levin, B. R.; Selander, R K

    1984-01-01

    Isolates from the intestinal Escherichia coli flora of 28 members of five families (including parents, children, and household pets) in Amherst, Massachusetts, and Rochester, New York, were characterized by the electrophoretic mobilities of 12 enzymes to estimate the extent of sharing of strains among associated and unassociated hosts. Among the 655 isolates examined, 60 different combinations of electromorphs (electrophoretic types or ETs), each representing a distinctive multilocus genotype...

  19. The role of geography and host abundance in the distribution of parasitoids of an alien pest.

    Science.gov (United States)

    Nováková, Petra; Holuša, Jaroslav; Horák, Jakub

    2016-01-01

    Chalcid wasps (Hymenoptera: Chalcidoidea) are probably the most effective and abundant parasitoids of the horse chestnut leaf miner (Cameraria ohridella), an alien pest in Europe that lacks specialized enemies. We studied how the species richness and abundance of chalcids are influenced by altitude, direction of an alien spread and host abundance of C. ohridella. We quantified the numbers and species richness of chalcid wasps and the numbers of C. ohridella that emerged from horse chestnut (Aesculus hippocastanum) leaf litter samples collected from 35 sites in the Czech Republic. Species richness of chalcids, which was considered an indicator of the possible adaptation of parasitoids to this alien host, was unrelated to C. ohridella abundance, direction of spread, or altitude. Chalcid abundance, which was considered an indicator of parasitism of the alien host, was strongly and positively related to C. ohridella abundance. Chalcid abundance was negatively related to direction of spread and positively related, although in a non-linear manner, to altitude. The relationship of chalcid abundance with direction of spread and altitude was weaker than that with C. ohridella abundance. The results provide evidence that biological control of the alien pest C. ohridella by natural enemies might develop in the future. PMID:26819849

  20. The role of geography and host abundance in the distribution of parasitoids of an alien pest

    Science.gov (United States)

    Nováková, Petra; Holuša, Jaroslav

    2016-01-01

    Chalcid wasps (Hymenoptera: Chalcidoidea) are probably the most effective and abundant parasitoids of the horse chestnut leaf miner (Cameraria ohridella), an alien pest in Europe that lacks specialized enemies. We studied how the species richness and abundance of chalcids are influenced by altitude, direction of an alien spread and host abundance of C. ohridella. We quantified the numbers and species richness of chalcid wasps and the numbers of C. ohridella that emerged from horse chestnut (Aesculus hippocastanum) leaf litter samples collected from 35 sites in the Czech Republic. Species richness of chalcids, which was considered an indicator of the possible adaptation of parasitoids to this alien host, was unrelated to C. ohridella abundance, direction of spread, or altitude. Chalcid abundance, which was considered an indicator of parasitism of the alien host, was strongly and positively related to C. ohridella abundance. Chalcid abundance was negatively related to direction of spread and positively related, although in a non-linear manner, to altitude. The relationship of chalcid abundance with direction of spread and altitude was weaker than that with C. ohridella abundance. The results provide evidence that biological control of the alien pest C. ohridella by natural enemies might develop in the future. PMID:26819849

  1. Viral genome size distribution does not correlate with the antiquity of the host lineages

    Directory of Open Access Journals (Sweden)

    José Alberto Campillo-Balderas

    2015-12-01

    Full Text Available It has been suggested that RNA viruses and other subcellular entities endowed with RNA genomes are relicts from an ancient RNA/protein World which is believed to have preceded extant DNA/RNA/protein-based cells. According to their proponents, this possibility is supported by the small-genome sizes of RNA viruses and their manifold replication strategies, which have been interpreted as the result of an evolutionary exploration of different alternative genome organizations and replication strategies during early evolutionary stages. At the other extreme are the giant DNA viruses, whose genome sizes can be as large as those of some prokaryotes, and which have been grouped by some authors into a fourth domain of life. As argued here, the comparative analysis of the chemical nature and sizes of the viral genomes reported in GenBank does not reveal any obvious correlation with the phylogenetic history of their hosts. Accordingly, it is somewhat difficult to reconcile the proposal of the putative pre-DNA antiquity of RNA viruses, with their extraordinary diversity in plant hosts and their apparent absence among the Archaea. Other issues related to the genome size of all known viruses and subviral agents and the relationship with their hosts are discussed.

  2. Distribution, prevalence and host specificity of avian malaria parasites across the breeding range of the migratory lark sparrow (Chondestes grammacus).

    Science.gov (United States)

    Swanson, Bethany L; Lyons, Amanda C; Bouzat, Juan L

    2014-06-01

    The lark sparrow (Chondestes grammacus) is a ground-nesting passerine that breeds across much of the central North American steppe and sand barrens. Through genotyping and sequencing of avian malaria parasites we examined levels of malaria prevalence and determined the distribution of Haemoproteus and Plasmodium lineages across the breeding range of the lark sparrow. Analysis of 365 birds collected from five breeding locations revealed relatively high levels of malaria prevalence in adults (80 %) and juveniles (46 %), with infections being primarily of Haemoproteus (91 % of sequenced samples). Levels of genetic diversity and genetic structure of malaria parasites with respect to the avian host populations revealed distinct patterns for Haemoproteus and Plasmodium, most likely as a result of their distinct life histories, host specificity, and transmission vectors. With the exception of one common Haemoproteus haplotype detected in all populations, all other haplotypes were either population-specific or shared by two to three populations. A hierarchical analysis of molecular variance of Haemoproteus sequences revealed that 15-18 % of the genetic variation can be explained by differences among host populations/locations (p < 0.001). In contrast to the regional patterns of genetic differentiation detected for the lark sparrow populations, Haemoproteus parasites showed high levels of population-specific variation and no significant differences among regions, which suggests that the population dynamics of the parasites may be driven by evolutionary processes operating at small spatial scales (e.g., at the level of host populations). These results highlight the potential effects of host population structure on the demographic and evolutionary dynamics of parasites.

  3. Distribution patterns of the subtropical evergreen broad-leaved forests of southwestern China, as compared with those of the eastern Chinese subtropical regions

    Directory of Open Access Journals (Sweden)

    Tang, C. Q.

    2015-12-01

    Full Text Available This paper analyzes the geographic distribution patterns of the subtropical evergreen broad-leaved forests of southwestern China, and compares with other subtropical regions in the east of China in terms of forest types, pertinent species, and spatial distribution along latitudinal, longitudinal and altitudinal gradients. In general, for both the western and the eastern subtropical regions, the evergreen broad-leaved forests are dominated by species of Castanopsis, Lithocarpus, Cyclobalanopsis (Fagaceae, Machilus, Cinnamomum (Lauraceae, Schima (Theaceae, Manglietia, and Michelia, (Magnoliaceae, while in southwestern China there are more diverse forest types including semi-humid, monsoon, mid-montane moist and humid evergreen broad-leaved forests, but only monsoon and humid forests in the east. The Yunnan area has more varied species of Lithocarpus or Cyclobalanopsis or Castanopsis as dominants than does eastern China, where the chief dominant genus is Castanopsis. The upper limits of the evergreen broad-leaved forests are mainly 2400–2800 m in western Yunnan and western Sichuan, much higher than in eastern China (600–1500, but 2500 m in Taiwan. Also discussed are the environmental effects on plant diversity of the evergreen broad-leaved forest ecosystems exemplified by Yunnan and Taiwan.En este trabajo se analiza los patrones de distribución geográfica de los bosques subtropicales perennifolios de hoja ancha del suroeste de china, y se comparan con los de otras regiones subtropicales del este de China en términos de tipología de bosque, especies relevantes, y distribución espacial a lo largo de un gradiente latitudinal, longitudinal y altitudinal. De manera general, los bosques perennifolios de hoja ancha de la regiones subtropicales tanto orientales como occidentales presentan dominancia de especies de Castanopsis, Lithocarpus, Cyclobalanopsis (Fagaceae, Machilus, Cinnamomum (Lauraceae, Schima (Theaceae, Manglietia y Michelia

  4. Genomic, proteomic and morphological characterization of two novel broad host lytic bacteriophages ΦPD10.3 and ΦPD23.1 infecting pectinolytic Pectobacterium spp. and Dickeya spp.

    Directory of Open Access Journals (Sweden)

    Robert Czajkowski

    Full Text Available Pectinolytic Pectobacterium spp. and Dickeya spp. are necrotrophic bacterial pathogens of many important crops, including potato, worldwide. This study reports on the isolation and characterization of broad host lytic bacteriophages able to infect the dominant Pectobacterium spp. and Dickeya spp. affecting potato in Europe viz. Pectobacterium carotovorum subsp. carotovorum (Pcc, P. wasabiae (Pwa and Dickeya solani (Dso with the objective to assess their potential as biological disease control agents. Two lytic bacteriophages infecting stains of Pcc, Pwa and Dso were isolated from potato samples collected from two potato fields in central Poland. The ΦPD10.3 and ΦPD23.1 phages have morphology similar to other members of the Myoviridae family and the Caudovirales order, with a head diameter of 85 and 86 nm and length of tails of 117 and 121 nm, respectively. They were characterized for optimal multiplicity of infection, the rate of adsorption to the Pcc, Pwa and Dso cells, the latent period and the burst size. The phages were genotypically characterized with RAPD-PCR and RFLP techniques. The structural proteomes of both phages were obtained by fractionation of phage proteins by SDS-PAGE. Phage protein identification was performed by liquid chromatography-mass spectrometry (LC-MS analysis. Pulsed-field gel electrophoresis (PFGE, genome sequencing and comparative genome analysis were used to gain knowledge of the length, organization and function of the ΦPD10.3 and ΦPD23.1 genomes. The potential use of ΦPD10.3 and ΦPD23.1 phages for the biocontrol of Pectobacterium spp. and Dickeya spp. infections in potato is discussed.

  5. Global Transcriptional Regulation of Backbone Genes in Broad-Host-Range Plasmid RA3 from the IncU Group Involves Segregation Protein KorB (ParB Family).

    Science.gov (United States)

    Kulinska, Anna; Godziszewska, Jolanta; Wojciechowska, Anna; Ludwiczak, Marta; Jagura-Burdzy, Grazyna

    2016-04-01

    The KorB protein of the broad-host-range conjugative plasmid RA3 from the IncU group belongs to the ParB family of plasmid and chromosomal segregation proteins. As a partitioning DNA-binding factor, KorB specifically recognizes a 16-bp palindrome which is an essential motif in the centromere-like sequence parSRA3, forms a segrosome, and together with its partner IncC (ParA family) participates in active DNA segregation ensuring stable plasmid maintenance. Here we show that by binding to this palindromic sequence, KorB also acts as a repressor for the adjacent mobC promoter driving expression of the mobC-nicoperon, which is involved in DNA processing during conjugation. Three other promoters, one buried in the conjugative transfer module and two divergent promoters located at the border between the replication and stability regions, are regulated by KorB binding to additional KorB operators (OBs). KorB acts as a repressor at a distance, binding to OBs separated from their cognate promoters by between 46 and 1,317 nucleotides. This repressor activity is facilitated by KorB spreading along DNA, since a polymerization-deficient KorB variant with its dimerization and DNA-binding abilities intact is inactive in transcriptional repression. KorB may act as a global regulator of RA3 plasmid functions in Escherichia coli, since its overexpression in transnegatively interferes with mini-RA3 replication and stable maintenance of RA3. PMID:26850301

  6. Genomic, proteomic and morphological characterization of two novel broad host lytic bacteriophages ΦPD10.3 and ΦPD23.1 infecting pectinolytic Pectobacterium spp. and Dickeya spp.

    Science.gov (United States)

    Czajkowski, Robert; Ozymko, Zofia; de Jager, Victor; Siwinska, Joanna; Smolarska, Anna; Ossowicki, Adam; Narajczyk, Magdalena; Lojkowska, Ewa

    2015-01-01

    Pectinolytic Pectobacterium spp. and Dickeya spp. are necrotrophic bacterial pathogens of many important crops, including potato, worldwide. This study reports on the isolation and characterization of broad host lytic bacteriophages able to infect the dominant Pectobacterium spp. and Dickeya spp. affecting potato in Europe viz. Pectobacterium carotovorum subsp. carotovorum (Pcc), P. wasabiae (Pwa) and Dickeya solani (Dso) with the objective to assess their potential as biological disease control agents. Two lytic bacteriophages infecting stains of Pcc, Pwa and Dso were isolated from potato samples collected from two potato fields in central Poland. The ΦPD10.3 and ΦPD23.1 phages have morphology similar to other members of the Myoviridae family and the Caudovirales order, with a head diameter of 85 and 86 nm and length of tails of 117 and 121 nm, respectively. They were characterized for optimal multiplicity of infection, the rate of adsorption to the Pcc, Pwa and Dso cells, the latent period and the burst size. The phages were genotypically characterized with RAPD-PCR and RFLP techniques. The structural proteomes of both phages were obtained by fractionation of phage proteins by SDS-PAGE. Phage protein identification was performed by liquid chromatography-mass spectrometry (LC-MS) analysis. Pulsed-field gel electrophoresis (PFGE), genome sequencing and comparative genome analysis were used to gain knowledge of the length, organization and function of the ΦPD10.3 and ΦPD23.1 genomes. The potential use of ΦPD10.3 and ΦPD23.1 phages for the biocontrol of Pectobacterium spp. and Dickeya spp. infections in potato is discussed.

  7. Constraining the properties of AGN host galaxies with Spectral Energy Distribution modeling

    CERN Document Server

    Ciesla, L; Georgakakis, A; Bernhard, E; Mitchell, P D; Buat, V; Elbaz, D; Floc'h, E Le; Lacey, C G; Magdis, G E; Xilouris, M

    2015-01-01

    [abridged] We use the latest release of CIGALE, a galaxy SED fitting model relying on energy balance, to study the influence of an AGN in estimating both the SFR and stellar mass in galaxies, as well as the contribution of the AGN to the power output of the host. Using the galaxy formation SAM GALFORM, we create mock galaxy SEDs using realistic star formation histories (SFH) and add an AGN of Type 1, Type 2, or intermediate type whose contribution to the bolometric luminosity can be variable. We perform an SED fitting of these catalogues with CIGALE assuming three different SFHs: a single- and double-exponentially-decreasing, and a delayed SFH. Constraining thecontribution of an AGN to the LIR (fracAGN) is very challenging for fracAGN<20%, with uncertainties of ~5-30% for higher fractions depending on the AGN type, while FIR and sub-mm are essential. The AGN power has an impact on the estimation of $M_*$ in Type 1 and intermediate type AGNs but has no effect for galaxies hosting Type 2 AGNs. We find that i...

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

    DEFF Research Database (Denmark)

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

    2005-01-01

    by developing annual and seasonal composite models, and iteratively analysing for their relationship with parasite and snail distribution. The dry season composite model predicted an endemic area that produced the best fit with the distribution of schools with > or =5% prevalence. NDVI values of 151-174, day...... temperatures of 26-36 degrees C, and night temperatures of 15-20 degrees C were used as criteria for the prediction model. Using the same approach with host snail data indicated that most of Uganda is suitable "B. pfeifferi"/B. sudanica habitat, except for possibly the north-eastern region of the country...... climate data on precipitation, as the best ecological determinants of the S. mansoni-"B. pfeifferi"/B. sudanica system. Satellite composite models and logistic regression analysis, suggest low night time temperature as one of the significant factors inhibiting S. mansoni transmission in the south...

  9. Distribution of the Primary Endosymbiont (Candidatus Uzinura Diaspidicola Within Host Insects from the Scale Insect Family Diaspididae

    Directory of Open Access Journals (Sweden)

    Katharina Dittmar

    2012-02-01

    Full Text Available It has long been known that armored scale insects harbor endosymbiotic bacteria inside specialized cells called bacteriocytes. Originally, these endosymbionts were thought to be fungal symbionts but they are now known to be bacterial and have been named Uzinura diaspidicola. Bacteriocyte and endosymbiont distribution patterns within host insects were visualized using in situ hybridization via 16S rRNA specific probes. Images of scale insect embryos, eggs and adult scale insects show patterns of localized bacteriocytes in embryos and randomly distributed bacteriocytes in adults. The symbiont pocket was not found in the armored scale insect eggs that were tested. The pattern of dispersed bacteriocytes in adult scale insects suggest that Uzinura and Blattabacteria may share some homologous traits that coincide with similar life style requirements, such as dispersal in fat bodies and uric acid recycling.

  10. Distribution of the Primary Endosymbiont (Candidatus Uzinura Diaspidicola) Within Host Insects from the Scale Insect Family Diaspididae.

    Science.gov (United States)

    Gruwell, Matthew E; Flarhety, Meghan; Dittmar, Katharina

    2012-01-01

    It has long been known that armored scale insects harbor endosymbiotic bacteria inside specialized cells called bacteriocytes. Originally, these endosymbionts were thought to be fungal symbionts but they are now known to be bacterial and have been named Uzinura diaspidicola. Bacteriocyte and endosymbiont distribution patterns within host insects were visualized using in situ hybridization via 16S rRNA specific probes. Images of scale insect embryos, eggs and adult scale insects show patterns of localized bacteriocytes in embryos and randomly distributed bacteriocytes in adults. The symbiont pocket was not found in the armored scale insect eggs that were tested. The pattern of dispersed bacteriocytes in adult scale insects suggest that Uzinura and Blattabacteria may share some homologous traits that coincide with similar life style requirements, such as dispersal in fat bodies and uric acid recycling.

  11. Ancylostoma (Ancylostoma) buckleyi (Nematoda: Ancylostomatidae): new wild host and distribution expansion.

    Science.gov (United States)

    Scioscia, Nathalia Paula; Beldomenico, Pablo Martín; Denegri, Guillermo María

    2016-06-01

    Here we report the occurrence of Ancylostoma (Ancylostoma) buckleyi (Le Roux and Biocca, 1957) (Nematoda: Ancylostomatidae) in the small intestine of Pampas foxes (Lycalopex gymnocercus) (Mammalia: Canidae). This fox is the most abundant native carnivore in southern South America, where it inhabits grasslands, open woodlands and areas highly modified by extensive ranching and agricultural activities. Material from 80 foxes in rural areas of southern Buenos Aires province, Argentina was examined. The intestinal tracts were carefully removed from each carcass and subsequently isolated by ligatures (pylorus and rectum). Examination of the intestinal content was performed using the sedimentation and counting technique. Four foxes (5%) were found to be parasitized with adult specimens of A. buckleyi. This is the first report of Ancylostoma (A.) buckleyi in Argentina and adds L. gymnocercus as new host of this nematode species. PMID:27334825

  12. Ancylostoma (Ancylostoma buckleyi (Nematoda: Ancylostomatidae: new wild host and distribution expansion

    Directory of Open Access Journals (Sweden)

    Nathalia Paula Scioscia

    2016-01-01

    Full Text Available Abstract Here we report the occurrence of Ancylostoma (Ancylostoma buckleyi (Le Roux and Biocca, 1957 (Nematoda: Ancylostomatidae in the small intestine of Pampas foxes (Lycalopex gymnocercus (Mammalia: Canidae. This fox is the most abundant native carnivore in southern South America, where it inhabits grasslands, open woodlands and areas highly modified by extensive ranching and agricultural activities. Material from 80 foxes in rural areas of southern Buenos Aires province, Argentina was examined. The intestinal tracts were carefully removed from each carcass and subsequently isolated by ligatures (pylorus and rectum. Examination of the intestinal content was performed using the sedimentation and counting technique. Four foxes (5% were found to be parasitized with adult specimens of A. buckleyi. This is the first report of Ancylostoma (A. buckleyi in Argentina and adds L. gymnocercus as new host of this nematode species.

  13. Metacercarial distribution of Centrocestus formosanus among fish hosts in the Guadalupe River drainage of Texas.

    Science.gov (United States)

    Fleming, B Paul; Huffman, David G; Bonner, Timothy H; Brandt, Thomas M

    2011-09-01

    We examined the gills of wild fish collected from central Texas for Centrocestus formosanus metacercariae to determine whether this temperature-restricted parasite had invaded the thermally dynamic Guadalupe River via an introduced population in its thermally stable tributary, the Comal River. We collected fish from three sites in the Guadalupe River near its confluence with the Comal River (upstream, at, and downstream) and one site in the Comal River. Centrocestus formosanus infected 14 of the 25 species examined (56.0%) and 171 of the individual fish (27.1%). Several of the infected fish represent new host records for the parasite, and two are listed as species of special concern by the state of Texas. Mean metacercarial intensities varied from 8 to 616 among species, and the highest recorded intensity was greater than 800 in two Guadalupe roundnose minnow Dionda nigrotaeniata. Among the 24 species examined from the Guadalupe River, 11 (45.8%) were infected with C. formosanus. Thorough surveys at the study sites yielded no living specimens of the first obligate intermediate snail host (red-rim melania Melanoides tuberculatus), which must be present to perpetuate the parasite. Thus, the infections were probably due to drifting cercariae that had been shed into the water column upstream of the study area in the Comal River. We therefore investigated spatial patterns in cercarial acquisition using caged fish to determine whether drifting cercariae were present in the water column at the study sites. Of 57 uninfected blacktail shiners Cyprinella venusta exposed to Guadalupe River water downstream from and at the confluence, 52 (91.2%) became infected with C. Formosanus metacercariae at a mean rate of 4 metacercariae/d. This finding extends the known geographic range of this invasive exotic parasite and is the first report of the life cycle being advanced in the fish assemblage of a thermally variable temperate stream in the USA.

  14. Orobanche caryophyllacea Sm. (Orobanchaceae in Poland: current distribution, taxonomy, plant communities and hosts

    Directory of Open Access Journals (Sweden)

    Renata Piwowarczyk

    2014-09-01

    Full Text Available The paper presents the current distribution of Orobanche caryophyllacea Sm. in Poland based on a critical revision of herbarium and literature data as well as the results of my field studies. The majority of localities are in south and south-eastern Poland: Małopolska Upland, Lublin Upland, Roztocze, Przemyśl Foothills, Pieniny Mts, rarely in the valleys of the Lower Vistula and Oder rivers or Wolin island. The distribution map in Poland is included. The taxonomy, biology and ecology of the species are discussed.

  15. Mitochondrial genome sequencing in Mesolithic North East Europe Unearths a new sub-clade within the broadly distributed human haplogroup C1.

    Directory of Open Access Journals (Sweden)

    Clio Der Sarkissian

    Full Text Available The human mitochondrial haplogroup C1 has a broad global distribution but is extremely rare in Europe today. Recent ancient DNA evidence has demonstrated its presence in European Mesolithic individuals. Three individuals from the 7,500 year old Mesolithic site of Yuzhnyy Oleni Ostrov, Western Russia, could be assigned to haplogroup C1 based on mitochondrial hypervariable region I sequences. However, hypervariable region I data alone could not provide enough resolution to establish the phylogenetic relationship of these Mesolithic haplotypes with haplogroup C1 mitochondrial DNA sequences found today in populations of Europe, Asia and the Americas. In order to obtain high-resolution data and shed light on the origin of this European Mesolithic C1 haplotype, we target-enriched and sequenced the complete mitochondrial genome of one Yuzhnyy Oleni Ostrov C1 individual. The updated phylogeny of C1 haplogroups indicated that the Yuzhnyy Oleni Ostrov haplotype represents a new distinct clade, provisionally coined "C1f". We show that all three C1 carriers of Yuzhnyy Oleni Ostrov belong to this clade. No haplotype closely related to the C1f sequence could be found in the large current database of ancient and present-day mitochondrial genomes. Hence, we have discovered past human mitochondrial diversity that has not been observed in modern-day populations so far. The lack of positive matches in modern populations may be explained by under-sampling of rare modern C1 carriers or by demographic processes, population extinction or replacement, that may have impacted on populations of Northeast Europe since prehistoric times.

  16. Hosting Capacity of Solar Photovoltaics in Distribution Grids under Different Pricing Schemes

    DEFF Research Database (Denmark)

    Carollo, Riccardo; Chaudhary, Sanjay Kumar; Pillai, Jayakrishnan Radhakrishna

    2015-01-01

    Most of the solar photovoltaic (SPV) installations are connected to distribution networks. The majority of these systems are represented by single-phase rooftop SPVs connected to residential low voltage (LV) grids. The large SPV shares lead to grid integration issues such as voltage rise...

  17. Nanoarchaeota, Their Sulfolobales Host, and Nanoarchaeota Virus Distribution across Yellowstone National Park Hot Springs.

    Science.gov (United States)

    Munson-McGee, Jacob H; Field, Erin K; Bateson, Mary; Rooney, Colleen; Stepanauskas, Ramunas; Young, Mark J

    2015-11-01

    Nanoarchaeota are obligate symbionts with reduced genomes first described from marine thermal vent environments. Here, both community metagenomics and single-cell analysis revealed the presence of Nanoarchaeota in high-temperature (∼90°C), acidic (pH ≈ 2.5 to 3.0) hot springs in Yellowstone National Park (YNP) (United States). Single-cell genome analysis of two cells resulted in two nearly identical genomes, with an estimated full length of 650 kbp. Genome comparison showed that these two cells are more closely related to the recently proposed Nanobsidianus stetteri from a more neutral YNP hot spring than to the marine Nanoarchaeum equitans. Single-cell and catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) analysis of environmental hot spring samples identified the host of the YNP Nanoarchaeota as a Sulfolobales species known to inhabit the hot springs. Furthermore, we demonstrate that Nanoarchaeota are widespread in acidic to near neutral hot springs in YNP. An integrated viral sequence was also found within one Nanoarchaeota single-cell genome and further analysis of the purified viral fraction from environmental samples indicates that this is likely a virus replicating within the YNP Nanoarchaeota.

  18. Nanoarchaeota, Their Sulfolobales Host, and Nanoarchaeota Virus Distribution across Yellowstone National Park Hot Springs.

    Science.gov (United States)

    Munson-McGee, Jacob H; Field, Erin K; Bateson, Mary; Rooney, Colleen; Stepanauskas, Ramunas; Young, Mark J

    2015-11-01

    Nanoarchaeota are obligate symbionts with reduced genomes first described from marine thermal vent environments. Here, both community metagenomics and single-cell analysis revealed the presence of Nanoarchaeota in high-temperature (∼90°C), acidic (pH ≈ 2.5 to 3.0) hot springs in Yellowstone National Park (YNP) (United States). Single-cell genome analysis of two cells resulted in two nearly identical genomes, with an estimated full length of 650 kbp. Genome comparison showed that these two cells are more closely related to the recently proposed Nanobsidianus stetteri from a more neutral YNP hot spring than to the marine Nanoarchaeum equitans. Single-cell and catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) analysis of environmental hot spring samples identified the host of the YNP Nanoarchaeota as a Sulfolobales species known to inhabit the hot springs. Furthermore, we demonstrate that Nanoarchaeota are widespread in acidic to near neutral hot springs in YNP. An integrated viral sequence was also found within one Nanoarchaeota single-cell genome and further analysis of the purified viral fraction from environmental samples indicates that this is likely a virus replicating within the YNP Nanoarchaeota. PMID:26341207

  19. Orobanche lutea Baumg. (Orobanchaceae in Poland: revised distribution, taxonomy, phytocoenological and host relations

    Directory of Open Access Journals (Sweden)

    Piwowarczyk Renata

    2014-06-01

    Full Text Available The paper presents current distribution of Orobanche lutea Baumg. in Poland based on a critical revision of herbarium and literature data as well as results of field investigations conducted between 1999-2014. Majority of localities are centred around the Silesia-Cracow, Małopolska and Lublin-Lviv Uplands. The greatest density of sites with probably the most abundant populations in Europe is in the central part of Silesia-Cracow Upland, which, by several hundred years, was heavily exploited for calamine mining (rich in zinc, lead and silver. This resulted in the formation of large areas of gangue containing toxic heavy metals. Since limestone, dolomite, marl and postglacial calcareous clay and sands occur there in most places, the soil is often strongly calcareous. Populations of O. lutea contain here many thousands of shoots. The distribution of the species in Poland is mapped. The taxonomy, biology, ecology and threats are also discussed.

  20. Distribution, host plants and natural enemies of sugar beet root aphid (Pemphigus fuscicornis) In Slovakia

    OpenAIRE

    Tóth Peter; Tancik Ján I.; Tóthová Monika; Pačuta Vladimir

    2006-01-01

    During 2003-2004, field surveys were realized to observe the distribution of sugar beet aphid, Pemphigus fuscicornis (K o c h) (Sternorrhyncha Pemphigidae) in southwestern Slovakia. The research was carried out at 60 different localities with altitudes 112-220 m a. s. l. Sugar beet root aphid was recorded at 30 localities. The aphid was recorded in Slovakia for the first time, but its occurrence was predicted and symptoms and harmfulness overlooked by now. The presence of P. fuscicornis was i...

  1. BLACK HOLE MASS AND EDDINGTON RATIO DISTRIBUTION FUNCTIONS OF X-RAY-SELECTED BROAD-LINE AGNs AT z {approx} 1.4 IN THE SUBARU XMM-NEWTON DEEP FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Nobuta, K.; Akiyama, M. [Astronomical Institute, Tohoku University, 6-3 Aramaki, Aoba-ku, Sendai 980-8578 (Japan); Ueda, Y.; Hiroi, K.; Ohta, K.; Iwamuro, F.; Yabe, K.; Moritani, Y.; Sumiyoshi, M.; Maihara, T. [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Watson, M. G. [XROA Group, Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Silverman, J.; Tamura, N.; Kimura, M. [Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8583 (Japan); Takato, N. [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Dalton, G.; Lewis, I.; Bonfield, D.; Lee, H.; Curtis-Lake, E., E-mail: akiyama@astr.tohoku.ac.jp [Department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); and others

    2012-12-20

    In order to investigate the growth of supermassive black holes (SMBHs), we construct the black hole mass function (BHMF) and Eddington ratio distribution function (ERDF) of X-ray-selected broad-line active galactic nuclei (AGNs) at z {approx} 1.4 in the Subaru XMM-Newton Deep Survey (SXDS) field. A significant part of the accretion growth of SMBHs is thought to take place in this redshift range. Black hole masses of X-ray-selected broad-line AGNs are estimated using the width of the broad Mg II line and 3000 A monochromatic luminosity. We supplement the Mg II FWHM values with the H{alpha} FWHM obtained from our NIR spectroscopic survey. Using the black hole masses of broad-line AGNs at redshifts between 1.18 and 1.68, the binned broad-line AGN BHMFs and ERDFs are calculated using the V{sub max} method. To properly account for selection effects that impact the binned estimates, we derive the corrected broad-line AGN BHMFs and ERDFs by applying the maximum likelihood method, assuming that the ERDF is constant regardless of the black hole mass. We do not correct for the non-negligible uncertainties in virial BH mass estimates. If we compare the corrected broad-line AGN BHMF with that in the local universe, then the corrected BHMF at z = 1.4 has a higher number density above 10{sup 8} M{sub Sun} but a lower number density below that mass range. The evolution may be indicative of a downsizing trend of accretion activity among the SMBH population. The evolution of broad-line AGN ERDFs from z = 1.4 to 0 indicates that the fraction of broad-line AGNs with accretion rates close to the Eddington limit is higher at higher redshifts.

  2. A baseline analysis of the distribution, host-range, and severity of the rust Puccinia Psidii in the Hawaiian islands, 2005-2010

    Science.gov (United States)

    Anderson, Robert C.

    2012-01-01

    Puccinia psidii was first described by Winter (1884) on guava (Psidium guajava L.) in Brazil. The rust is still a major pest of native guava in Brazil and is often referred to as “guava rust” internationally. It is unusual among rust fungi because of its broad and ever-expanding host-range within the Myrtaceae plant family (Simpson et al. 2006). The pathogen is regarded as a major threat to Eucalyptus plantations and other Myrtaceae worldwide (Coutinho et al. 1998, Grgurinovic et al. 2006, Glen et al. 2007). Infections of leaves and meristems are particularly severe on susceptible seedlings, cuttings, young trees, and coppice, causing plants to be stunted and multi-branched, inhibiting normal growth and development, and sometimes causing death to young seedlings (Booth et al. 2000, Rayachhetry et al. 2001). The fungus has expanded its host-range in Brazil, affecting both native and introduced Myrtaceae (Coutinho et al. 1998). Since its discovery in 1884, P. psidii has continually been discovered to have an expanding host-range within the Myrtaceae, affecting hosts throughout much of South and Central America and the Caribbean. Spreading out originally from Brazil in 1884, the fungus has been reported on hosts in the following countries (first record in parentheses): Paraguay (1884), Uruguay (1889), Ecuador (1891), Colombia (1913), Puerto Rico (1913), Cuba (1926), Dominican Republic (1933), Venezuela (1934), Jamaica (1936), Argentina (1946), Dominica (1948), Trinidad and Tobago (1951), Guatemala (1968), United States (Florida; 1977), Mexico (1981), El Salvador (1987), and Costa Rica (1998) (Simpson et al. 2006). It is possible that P. psidii was present in El Salvador and Costa Rica prior to 1980, but was not reported until 1987 and 1998, respectively. Until recently, Puccinia psidii was restricted to the Neotropics, Mexico, and the state of Florida in the United States. While the rust has been present in Florida for over 30 years, only recently has it spread

  3. Reaching the Peak of the quasar spectral energy distribution - II. Exploring the accretion disc, dusty torus and host galaxy

    CERN Document Server

    Collinson, James S; Landt, Hermine; Done, Chris; Elvis, Martin; McDowell, Jonathan C

    2016-01-01

    We continue our study of the spectral energy distributions (SEDs) of 11 AGN at 1.5 < z < 2.2, with optical-NIR spectra, X-ray data and mid-IR photometry. In a previous paper we presented the observations and models; in this paper we explore the parameter space of these models. We first quantify uncertainties on the black hole masses (M$_{\\rm BH}$) and degeneracies between SED parameters. The effect of BH spin is tested, and we find that while low to moderate spin values (a$_*$ $\\leq$ 0.9) are compatible with the data in all cases, maximal spin (a$_*$ = 0.998) can only describe the data if the accretion disc is face-on. The outer accretion disc radii are well constrained in 8/11 objects, and are found to be a factor ~5 smaller than the self-gravity radii. We then extend our modelling campaign into the mid-IR regime with WISE photometry, adding components for the host galaxy and dusty torus. Our estimates of the host galaxy luminosities are consistent with the M$_{\\rm BH}$-bulge relationship, and the meas...

  4. Targeting hunter distribution based on host resource selection and kill sites to manage disease risk

    DEFF Research Database (Denmark)

    Dugal, Cherie; van Beest, Floris; Vander Wal, Eric;

    2013-01-01

    , in southwestern Manitoba, Canada. Distance to protected area was the most important covariate influencing resource selection and hunter-kill sites of elk (AICw = 1.00). Collared adult males (which are most likely to be infected with bovine tuberculosis (Mycobacterium bovis) and chronic wasting disease) rarely......Endemic and emerging diseases are rarely uniform in their spatial distribution or prevalence among cohorts of wildlife. Spatial models that quantify risk-driven differences in resource selection and hunter mortality of animals at fine spatial scales can assist disease management by identifying high......-risk areas and individuals. We used resource selection functions (RSFs) and selection ratios (SRs) to quantify sex- and age-specific resource selection patterns of collared (n = 67) and hunter-killed (n = 796) nonmigratory elk (Cervus canadensis manitobensis) during the hunting season between 2002 and 2012...

  5. The use of Skylab data to study the early detection of insect infestations and density and distribution of host plants

    Science.gov (United States)

    Hart, W. G.; Ingle, S. J.; Davis, M. R.

    1975-01-01

    The detection of insect infestations and the density and distribution of host plants were studied using Skylab data, aerial photography and ground truth simultaneously. Additional ground truth and aerial photography were acquired between Skylab passes. Three test areas were selected: area 1, of high density citrus, was located northwest of Mission, Texas; area 2, 20 miles north of Weslaco, Texas, irrigated pastures and brush-covered land; area 3 covered the entire Lower Rio Grande Valley and adjacent areas of Mexico. A color composite picture of S-190A data showed patterns of vegetation on both sides of the Rio Grande River clearly delineating the possible avenues of entry of pest insects from Mexico into the United States or from the United States into Mexico. Vegetation that could be identified with conventional color and color IR film included: citrus, brush, sugarcane, alfalfa, irrigated and unimproved pastures.

  6. Geographic distribution and host plants of Raoiella indica and associated mite species in northern Venezuela.

    Science.gov (United States)

    Vásquez, Carlos; de Moraes, Gilberto J

    2013-05-01

    The red palm mite (RPM), Raoiella indica Hirst (Acari: Tenuipalpidae), is an invasive pest in the New World, where it is currently considered a serious threat to coconut and banana crops. It was first reported from northern Venezuela in 2007. To determine its current distribution in this country, surveys were carried out from October 2008 to April 2010 on coconut (Cocos nucifera L.), banana (Musa spp.), ornamental plants and weeds in northern Venezuela. Higher population levels of RPM were registered on commercial coconut farms in Falcón and Sucre states but also on other plant species naturally growing along the coastal line in Anzoategui, Aragua, Carabobo, Monagas and Nueva Esparta states. Out of 34 botanical species evaluated, all RPM stages were observed only on eight arecaceous, one musaceous and one streliziaceous species, indicating that the pest developed and reproduced only on these plants. Mite specimens found on weeds were considered spurious events, as immature stages of the pest were never found on these. Amblyseius largoensis (Muma) (Acari: Phytoseiidae) was the most frequent predatory mite associated with RPM in all sampling sites. The results indicate that RPM has spread to extensive areas of northern Venezuela since its initial detection in Güiria, Sucre state. Considering the report of this pest mite in northern Brazil in the late 2009, additional samplings in southern Venezuela should be carried out, to evaluate the possible presence of RPM also in that region. PMID:23065034

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

    Science.gov (United States)

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

    2015-12-01

    Specimens of Transversotrema patialense (sensu lato) ( Soparkar, 1924 ) Crusz and Sathananthan, 1960 (Digenea: Transversotrematidae) infected the skin (epidermal spaces beneath scales near pectoral fins) of 4 of 126 (prevalence 3%; mean intensity 1.8) zebrafish ( Danio rerio (Hamilton, 1822) [Cypriniformes: Cyprinidae]) purchased in 2009 and cultured by a California (USA) fish supplier. These fish were sold as "laboratory-reared" and "specific pathogen free," purportedly raised in a recirculating aquaculture system that included zebrafish only. We herein describe the morphological features of this transversotrematid using light and scanning electron microscopy, provide a comprehensive list of hosts (snails and fishes) and geographic locality records for specimens reported as T. patialense, which is perhaps a species complex, and provide a brief historical synopsis of the taxonomic and life history research that has been conducted on this fluke. No species of Transversotrema previously had been reported from the Americas; however, this discovery is not surprising given that: (1) a suitable intermediate host (red-rimmed melania, Melanoides tuberculata (Müller, 1774) [Cerithioidea: Thiaridae]) has been established in California and elsewhere in North America, (2) the zebrafish is a susceptible definitive host, and (3) T. patialense reportedly matures on a broad ecological and phylogenetic spectrum of freshwater fishes. To our knowledge, this is the northern-most geographic locality record for a species of this genus. We suspect this case study represents an example of a parasite that may now be established in North America by the fortuitous co-occurrence of a susceptible, exotic snail host (the red-rimmed melania) and a susceptible, widely distributed, exotic fish host (the zebrafish). PMID:26335181

  8. Hopane, sterane and n-alkane distributions in shallow sediments hosting high arsenic groundwaters in Cambodia

    International Nuclear Information System (INIS)

    The presence of elevated As in ground waters exploited for drinking water and irrigation in South-East Asia is causing serious impacts on human health. A key mechanism that causes the mobilization of As in these waters is microbially mediated reductive transformation of As-bearing Fe(III) hydrated oxides and the role of degradable organic matter (OM) in this process is widely recognized. A number of different types of OM that drive As release in these aquifers have been suggested, including petroleum derived hydrocarbons naturally seeping into shallow sediments from deeper thermally mature source rocks. However, the amount of information on the characteristics of the OM in South-East Asian aquifers is limited. Here the organic geochemical analyses of the saturated hydrocarbon fractions and radiocarbon analysis, of two additional sites in SE Asia are reported. The results show that the OM in a given sedimentary horizon likely derives from multiple sources including naturally occurring petroleum. The importance of naturally occurring petroleum as one of the sources was clearly indicated by the n-alkane CPI of approximately 1, the presence of an unresolved complex mixture, and hopane (dominated by 17α(H),21β(H) hopanes) and sterane distribution patterns. The results also indicate that the OM in these aquifers varies tremendously in content, character and potential bioavailability. Furthermore, the presence of petroleum derived OM in sediments at both sites doubles the number of locations where their presence has been observed in association with As-rich, shallow aquifers, suggesting that the role of petroleum derived OM in microbially mediated As release might occur over a wider range of geographical locations than previously thought

  9. Supernovae and their host galaxies - III. The impact of bars and bulges on the radial distribution of supernovae in disc galaxies

    CERN Document Server

    Hakobyan, A A; Barkhudaryan, L V; Mamon, G A; Kunth, D; Petrosian, A R; Adibekyan, V; Aramyan, L S; Turatto, M

    2016-01-01

    We present an analysis of the impact of bars and bulges on the radial distributions of the different types of supernovae (SNe) in the stellar discs of host galaxies with various morphologies. We use a well-defined sample of 500 nearby (< 100 Mpc) SNe and their low-inclined (i < 60 deg) and morphologically non-disturbed S0-Sm host galaxies from the Sloan Digital Sky Survey. We find that in Sa-Sm galaxies, all core-collapse (CC) and vast majority of SNe Ia belong to the disc, rather than the bulge component. The radial distribution of SNe Ia in S0-S0/a galaxies is inconsistent with their distribution in Sa-Sm hosts, which is probably due to the contribution of the outer bulge SNe Ia in S0-S0/a galaxies. In Sa-Sbc galaxies, the radial distribution of CC SNe in barred hosts is inconsistent with that in unbarred ones, while the distributions of SNe Ia are not significantly different. At the same time, the radial distributions of both types of SNe in Sc-Sm galaxies are not affected by bars. We propose that th...

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

    Directory of Open Access Journals (Sweden)

    K. N. de Kock

    2008-09-01

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

  11. New Host and Distribution Records of the Leech Placobdella sophieaeOceguera-Figueroa et al., 2010 (Hirudinida: Glossiphoniidae)

    Science.gov (United States)

    Moser, William E.; Bowerman, Jay; Hovingh, Peter; Pearl, Christopher A.; Oceguera-Figueroa, Alajandro

    2014-01-01

    Placobdella sophieae Oceguera-Figueroa et al., 2010 (Hirudinida: Glossiphoniidae) is reported from Oregon, California, and British Columbia for the first time. New hosts reported for P. sophieae include Taricha granulosa (rough-skinned newt), Rana pretiosa (Oregon spotted frog), and Anaxyrus boreas (western toad). Placobdella sophieae exhibits relatively low host specificity and all amphibians occurring in the Pacific Northwest are potential hosts.

  12. The Effect of Host Star Spectral Energy Distribution and Ice-Albedo Feedback on the Climate of Extrasolar Planets

    CERN Document Server

    Shields, Aomawa L; Bitz, Cecilia M; Pierrehumbert, Raymond T; Joshi, Manoj M; Robinson, Tyler D

    2013-01-01

    Planetary climate can be affected by the interaction of the host star spectral energy distribution with the wavelength-dependent reflectivity of ice and snow. Here we explore this effect using a one dimensional (1-D), line-by-line, radiative-transfer model to calculate broadband planetary albedos as input to a seasonally varying, 1-D energy-balance climate model. A three-dimensional general circulation model is also used to explore the atmosphere's response to changes in incoming stellar radiation, or instellation, and surface albedo. Using this hierarchy of models we simulate planets covered by ocean, land, and water ice of varying grain size, with incident radiation from stars of different spectral types. Terrestrial planets orbiting stars with higher near-UV radiation exhibit a stronger ice-albedo feedback. We find that ice-covered conditions occur on an F-dwarf planet with only a 2% reduction in instellation relative to the present instellation on Earth, assuming fixed CO2 (present atmospheric level on Ea...

  13. In situ characterization of strain distribution in broad-area high-power lasers under operation by high-resolution x-ray diffraction and topography using synchrotron radiation

    Science.gov (United States)

    Zeimer, U.; Baumbach, T.; Grenzer, J.; Lübbert, D.; Mazuelas, A.; Pietsch, U.; Erbert, G.

    1999-05-01

    The strain distribution in broad-area high-power semiconductor laser diodes is investigated both before and during operation and degradation by high-resolution x-ray diffraction using synchrotron radiation. An inhomogeneous strain distribution along the stripe and at the stripe edges is found due to the mounting and bonding of the laser device. From the current-induced thermal lattice expansion the temperature rise during operation near the active region is estimated. The radius of curvature of the laser changes during operation and a different thermal behaviour on the front and the rear facet is found. The temperature distribution along the laser stripe could be correlated with the defect distribution observed after degradation by cathodoluminescence.

  14. In situ characterization of strain distribution in broad-area high-power lasers under operation by high-resolution x-ray diffraction and topography using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Zeimer, U.; Erbert, G. [Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik, Berlin (Germany); Baumbach, T. [Fraunhofer-Institut fuer Zerstoerungsfreie Pruefverfahren, Dresden (Germany); Grenzer, J.; Luebbert, D.; Mazuelas, A. [ESRF Grenoble, Grenoble (France); Pietsch, U. [Institut fuer Physik, Universitaet Potsdam, Potsdam (Germany)

    1999-05-21

    The strain distribution in broad-area high-power semiconductor laser diodes is investigated both before and during operation and degradation by high-resolution x-ray diffraction using synchrotron radiation. An inhomogeneous strain distribution along the stripe and at the stripe edges is found due to the mounting and bonding of the laser device. From the current-induced thermal lattice expansion the temperature rise during operation near the active region is estimated. The radius of curvature of the laser changes during operation and a different thermal behaviour on the front and the rear facet is found. The temperature distribution along the laser stripe could be correlated with the defect distribution observed after degradation by cathodoluminescence. (author)

  15. Distribution of populations of broad-snouted caiman (Caiman latirostris, Daudin 1802, Alligatoridae) in the São Francisco River basin, Brazil.

    Science.gov (United States)

    Filogonio, R; Assis, V B; Passos, L F; Coutinho, M E

    2010-11-01

    We surveyed populations of the broad-snouted caiman, Caiman latirostris, throughout the São Francisco River basin, from Três Marias reservoir, State of Minas Gerais, to the river delta, at the boarder of Sergipe and Alagoas states. We registered the occurrence of crocodilians in 61% of all surveyed localities (n = 64), in which the presence of C. latirostris was confirmed in 44% of the surveyed sites. Caimans occurred in both lentic and lotic habitats, although there was a preference for small dams, oxbow lakes and wetlands. Despite the hunting pressure and human impact on natural habitats, our results indicate that the populations of C. latirostris in the São Francisco basin are not fragmented. PMID:21180900

  16. Whose truffle is this? Distribution patterns of ectomycorrhizal fungal diversity in Tuber melanosporum brûlés developed in multi-host Mediterranean plant communities.

    Science.gov (United States)

    Taschen, Elisa; Sauve, Mathieu; Taudiere, Adrien; Parlade, Javier; Selosse, Marc-André; Richard, Franck

    2015-08-01

    In the Mediterranean region, patches of vegetation recovering from disturbance and transiently dominated by shrubs produce one of the world's most prized fungi, the black truffle (Tuber melanosporum). In these successional plant communities, we have fragmentary knowledge of the distribution of T. melanosporum in space among ectomycorrhizal (ECM) host species and in time. Molecular identification of hosts (Restriction Fragment Length Polymorphism) and fungi (Internal Transcribed Spacer sequencing) and quantification of T. melanosporum mycelium (quantitative Polymerase Chain Reaction) were employed to evaluate the presence of T. melanosporum on four dominant ECM host species (Quercus ilex, Quercus  coccifera, Arbutus unedo, Cistus albidus) and the extent to which their respective ECM communities shared fungal diversity, over the course of development of truffle grounds, from recent unproductive brûlés to senescent ones where production has stopped. We found that truffle grounds host rich communities in which multi-host fungal species dominate in frequency. When considering both ECM tips and soil mycelia, we documented a dynamic and spatially heterogeneous pattern of T. melanosporum distribution in soils and a presence of ECM tips restricted to Q. ilex roots. This study advances our knowledge of the ecology of T. melanosporum, and provides insight into the extent of ECM fungal sharing among plant species that dominate Mediterranean landscapes. PMID:25522815

  17. Absolute Magnetization Distribution on Back-arc Spreading Axis Hosting Hydrothermal Vents; Insight from Shinkai 6500 Magnetic Survey

    Science.gov (United States)

    Fujii, M.; Okino, K.; Honsho, C.; Mochizuki, N.; Szitkar, F.; Dyment, J.

    2013-12-01

    Near-bottom magnetic profiling using submersible, deep-tow, Remotely Operated Vehicle (ROV) and Autonomous Underwater Vehicle (AUV) make possible to conduct high-resolution surveys and depict detailed magnetic features reflecting, for instance, the presence of fresh lavas or hydrothermal alteration, or geomagnetic paleo-intensity variations. We conducted near-bottom three component magnetic measurements onboard submersible Shinkai 6500 in the Southern Mariana Trough, where five active hydrothermal vent fields (Snail, Yamanaka, Archean, Pica, and Urashima sites) have been found in both on- and off-axis areas of the active back-arc spreading center, to detect signals from hydrothermally altered rock and to distinguish old and new submarine lava flows. Fourteen dives were carried out at an altitude of 1-40 m during the R/V Yokosuka YK10-10 and YK10-11 cruises in 2010. We carefully corrected the effect of the induced and permanent magnetizations of the submersible by applying the correction method for the shipboard three-component magnetometer measurement modified for deep-sea measurement, and subtracted the IGRF values from the corrected data to obtain geomagnetic vector anomalies along the dive tracks. We then calculated the synthetic magnetic vector field produced by seafloor, assumed to be uniformly magnetized, using three dimensional forward modeling. Finally, values of the absolute magnetizations were estimated by using a linear transfer function in the Fourier domain from the observed and synthetic magnetic anomalies. The distribution of estimated absolute magnetization generally shows low values around the five hydrothermal vent sites. This result is consistent with the equivalent magnetization distribution obtained from previous AUV survey data. The areas of low magnetization are also consistent with hydrothermal deposits identified in video records. These results suggest that low magnetic signals are due to hydrothermal alteration zones where host rocks are

  18. The 2010 Broad Prize

    Science.gov (United States)

    Education Digest: Essential Readings Condensed for Quick Review, 2011

    2011-01-01

    A new data analysis, based on data collected as part of The Broad Prize process, provides insights into which large urban school districts in the United States are doing the best job of educating traditionally disadvantaged groups: African-American, Hispanics, and low-income students. Since 2002, The Eli and Edythe Broad Foundation has awarded The…

  19. Host and ecology both play a role in shaping distribution of digenean parasites of New Zealand whelks (Gastropoda: Buccinidae: Cominella).

    Science.gov (United States)

    Donald, Kirsten M; Spencer, Hamish G

    2016-08-01

    Digenean parasites infecting four Cominella whelk species (C. glandiformis, C. adspersa, C. maculosa and C. virgata), which inhabit New Zealand's intertidal zone, were analysed using molecular techniques. Mitochondrial 16S and cytochrome oxidase 1 (COI) and nuclear rDNA ITS1 sequences were used to infer phylogenetic relationships amongst digenea. Host species were parasitized by a diverse range of digenea (Platyhelminthes, Trematoda), representing seven families: Echinostomatidae, Opecoelidae, Microphallidae, Strigeidae and three, as yet, undetermined families A, B and C. Each parasite family infected between one and three host whelk species, and infection levels were typically low (average infection rates ranged from 1·4 to 3·6%). Host specificity ranged from highly species-specific amongst the echinostomes, which were only ever observed infecting C. glandiformis, to the more generalist opecoelids and strigeids, which were capable of infecting three out of four of the Cominella species analysed. Digeneans displayed a highly variable geographic range; for example, echinostomes had a large geographic range stretching the length of New Zealand, from Northland to Otago, whereas Family B parasites were restricted to fairly small areas of the North Island. Our results add to a growing body of research identifying wide ranges in both host specificity and geographic range amongst intertidal, multi-host parasite systems. PMID:27278710

  20. Systemic virus distribution and host responses in brain and intestine of chickens infected with low pathogenic or high pathogenic avian influenza virus

    Directory of Open Access Journals (Sweden)

    Post Jacob

    2012-03-01

    Full Text Available Abstract Background Avian influenza virus (AIV is classified into two pathotypes, low pathogenic (LP and high pathogenic (HP, based on virulence in chickens. Differences in pathogenicity between HPAIV and LPAIV might eventually be related to specific characteristics of strains, tissue tropism and host responses. Methods To study differences in disease development between HPAIV and LPAIV, we examined the first appearance and eventual load of viral RNA in multiple organs as well as host responses in brain and intestine of chickens infected with two closely related H7N1 HPAIV or LPAIV strains. Results Both H7N1 HPAIV and LPAIV spread systemically in chickens after a combined intranasal/intratracheal inoculation. In brain, large differences in viral RNA load and host gene expression were found between H7N1 HPAIV and LPAIV infected chickens. Chicken embryo brain cell culture studies revealed that both HPAIV and LPAIV could infect cultivated embryonic brain cells, but in accordance with the absence of the necessary proteases, replication of LPAIV was limited. Furthermore, TUNEL assay indicated apoptosis in brain of HPAIV infected chickens only. In intestine, where endoproteases that cleave HA of LPAIV are available, we found minimal differences in the amount of viral RNA and a large overlap in the transcriptional responses between HPAIV and LPAIV infected chickens. Interestingly, brain and ileum differed clearly in the cellular pathways that were regulated upon an AI infection. Conclusions Although both H7N1 HPAIV and LPAIV RNA was detected in a broad range of tissues beyond the respiratory and gastrointestinal tract, our observations indicate that differences in pathogenicity and mortality between HPAIV and LPAIV could originate from differences in virus replication and the resulting host responses in vital organs like the brain.

  1. Broad-scale genetic patterns of New Zealand abalone, Haliotis iris, across a distribution spanning 13° latitude and major oceanic water masses.

    Science.gov (United States)

    Will, Margaret; McCowan, Tom; Gemmell, Neil J

    2015-08-01

    The New Zealand black-foot abalone, Haliotis iris, or pāua, is endemic to the rocky reefs surrounding New Zealand, whose main land mass spans 13° of latitude and separates the Tasman Sea from the Pacific Ocean. In this study, we examined the population genetic structure of this important commercial, cultural and recreational species by genotyping nine microsatellite loci in 485 pāua from 27 locations distributed across mainland New Zealand and the Chatham Islands. We found low, but significant, levels of genetic differentiation. Key genetic breaks were identified among the Chatham Islands and mainland samples; patterns that are strongly corroborated by prior work employing mtDNA sequences. AMOVAs indicated that samples from the south of the North Island were more similar to the South Island samples than to other North Island samples, however multivariate analysis and Bayesian clustering could not identify a significant pattern. Differentiation between the Chatham Islands and the mainland is most likely due to isolation by distance, while differentiation of North Island samples corresponds with major components of New Zealand's oceanography, Cook Strait and the East Cape. Despite intense fishing pressure, we detected no signature of genetic bottlenecks in any region suggesting that population sizes have remained relatively stable over recent time or that the census size of this species is much larger than its effective population size.

  2. Broad-scale genetic patterns of New Zealand abalone, Haliotis iris, across a distribution spanning 13° latitude and major oceanic water masses.

    Science.gov (United States)

    Will, Margaret; McCowan, Tom; Gemmell, Neil J

    2015-08-01

    The New Zealand black-foot abalone, Haliotis iris, or pāua, is endemic to the rocky reefs surrounding New Zealand, whose main land mass spans 13° of latitude and separates the Tasman Sea from the Pacific Ocean. In this study, we examined the population genetic structure of this important commercial, cultural and recreational species by genotyping nine microsatellite loci in 485 pāua from 27 locations distributed across mainland New Zealand and the Chatham Islands. We found low, but significant, levels of genetic differentiation. Key genetic breaks were identified among the Chatham Islands and mainland samples; patterns that are strongly corroborated by prior work employing mtDNA sequences. AMOVAs indicated that samples from the south of the North Island were more similar to the South Island samples than to other North Island samples, however multivariate analysis and Bayesian clustering could not identify a significant pattern. Differentiation between the Chatham Islands and the mainland is most likely due to isolation by distance, while differentiation of North Island samples corresponds with major components of New Zealand's oceanography, Cook Strait and the East Cape. Despite intense fishing pressure, we detected no signature of genetic bottlenecks in any region suggesting that population sizes have remained relatively stable over recent time or that the census size of this species is much larger than its effective population size. PMID:26050219

  3. Geographic patterns of genetic variation in a broadly distributed marine vertebrate: new insights into loggerhead turtle stock structure from expanded mitochondrial DNA sequences.

    Directory of Open Access Journals (Sweden)

    Brian M Shamblin

    Full Text Available Previous genetic studies have demonstrated that natal homing shapes the stock structure of marine turtle nesting populations. However, widespread sharing of common haplotypes based on short segments of the mitochondrial control region often limits resolution of the demographic connectivity of populations. Recent studies employing longer control region sequences to resolve haplotype sharing have focused on regional assessments of genetic structure and phylogeography. Here we synthesize available control region sequences for loggerhead turtles from the Mediterranean Sea, Atlantic, and western Indian Ocean basins. These data represent six of the nine globally significant regional management units (RMUs for the species and include novel sequence data from Brazil, Cape Verde, South Africa and Oman. Genetic tests of differentiation among 42 rookeries represented by short sequences (380 bp haplotypes from 3,486 samples and 40 rookeries represented by long sequences (∼800 bp haplotypes from 3,434 samples supported the distinction of the six RMUs analyzed as well as recognition of at least 18 demographically independent management units (MUs with respect to female natal homing. A total of 59 haplotypes were resolved. These haplotypes belonged to two highly divergent global lineages, with haplogroup I represented primarily by CC-A1, CC-A4, and CC-A11 variants and haplogroup II represented by CC-A2 and derived variants. Geographic distribution patterns of haplogroup II haplotypes and the nested position of CC-A11.6 from Oman among the Atlantic haplotypes invoke recent colonization of the Indian Ocean from the Atlantic for both global lineages. The haplotypes we confirmed for western Indian Ocean RMUs allow reinterpretation of previous mixed stock analysis and further suggest that contemporary migratory connectivity between the Indian and Atlantic Oceans occurs on a broader scale than previously hypothesized. This study represents a valuable model for

  4. [Impact of water resource installations on the distribution of schistosomiasis and its intermediary hosts in Burkina Faso].

    Science.gov (United States)

    Poda, Jean-Noël; Sondo, Blaise; Parent, Gérard

    2003-01-01

    Dams generally are a favourable biotope for the molluscs acting as intermediary hosts to schistosomiasis. The importance of the schistosomiasis endemic which follows depends on the interactions taking place between the parasites and their definitive (humans) and intermediary hosts. A preliminary sound knowledge of the prevailing epidemiological situations is therefore necessary to define an efficient programme to fight these infections. The extension of schistosomiasis following the installation of water resource facilities is significative of the part played by these hosts. In the hydroagricultural complex of Sourou, the prevalence of urinary schistosomiasis increased from 19% in 1954 to more than 70% in 1998-1999 in Guiédougou, the most ancient site. As to digestive schistosomiasis, almost unheard of until 1987, its prevalence ranged from 8% to 69% in 1998 in the villages located alongside the areas thus equipped. In the Kou Valley, the prevalence went up from 14% in 1957 to 80% in 1974 for urinary schistosomiasis and from 1.3% to 45% for intestinal schistosomiasis. The same tendencies are likely to appear in the hydraulic installations of Bagré, Ziga, and Kompienga. Dams thus constitute amplifying factors for the proliferation of species and for parasite-host interactions. All the actors (developers, populations and scientists) are faced with the challenge of finding a mean to control the development of schistosomiasis infections which are likely to seriously lessen the benefits expected from these hydraulic installations.

  5. The properties of the host galaxy and the immediate environment of GRB 980425 / SN 1998bw from the multi-wavelength spectral energy distribution

    CERN Document Server

    Michałowski, Michał J; Malesani, Daniele; Michałowski, Tadeusz; Cerón, José María Castro; Reinfrank, Robert F; Garrett, Michael A; Fynbo, Johan P U; Watson, Darach J; Jørgensen, Uffe G

    2008-01-01

    We present an analysis of the spectral energy distribution (SED) of the galaxy ESO 184-G82, the host of the closest known long gamma-ray burst (GRB) 980425 and its associated supernova SN 1998bw. We use our observations obtained at the Australia Telescope Compact Array (the third >3 sigma radio detection of a GRB host) as well as archival infrared (IR) and ultraviolet (UV) observations to estimate its star formation state. We find that ESO 184-G82 has a UV star formation rate (SFR) and stellar mass consistent with the population of cosmological GRB hosts and of local dwarf galaxies. It has however a higher specific SFR (per unit stellar mass) and lower molecular gas-to-dust ratio than luminous spiral galaxies. The mass of ESO 184-G82 is dominated by an older stellar population in contrast to the majority of GRB hosts. The Wolf-Rayet region ~800 pc from the supernova site experienced a starburst episode during which the majority of its stellar population was built up. Unlike that of the entire galaxy, its SED ...

  6. A CENSUS OF BROAD-LINE ACTIVE GALACTIC NUCLEI IN NEARBY GALAXIES: COEVAL STAR FORMATION AND RAPID BLACK HOLE GROWTH

    International Nuclear Information System (INIS)

    We present the first quantified, statistical map of broad-line active galactic nucleus (AGN) frequency with host galaxy color and stellar mass in nearby (0.01 < z < 0.11) galaxies. Aperture photometry and z-band concentration measurements from the Sloan Digital Sky Survey are used to disentangle AGN and galaxy emission, resulting in estimates of uncontaminated galaxy rest-frame color, luminosity, and stellar mass. Broad-line AGNs are distributed throughout the blue cloud and green valley at a given stellar mass, and are much rarer in quiescent (red sequence) galaxies. This is in contrast to the published host galaxy properties of weaker narrow-line AGNs, indicating that broad-line AGNs occur during a different phase in galaxy evolution. More luminous broad-line AGNs have bluer host galaxies, even at fixed mass, suggesting that the same processes that fuel nuclear activity also efficiently form stars. The data favor processes that simultaneously fuel both star formation activity and rapid supermassive black hole accretion. If AGNs cause feedback on their host galaxies in the nearby universe, the evidence of galaxy-wide quenching must be delayed until after the broad-line AGN phase.

  7. Globular clusters as tracers of the host galaxy mass distribution: the Fornax dSph test case

    OpenAIRE

    Arca-Sedda, Manuel; Capuzzo-Dolcetta, Roberto

    2016-01-01

    The Fornax dwarf spheroidal galaxy is the most massive satellites of the Milky Way, claimed to be embedded in a huge dark matter halo, and the only among the Milky Way satellites hosting five globular clusters. Interestingly, their estimated masses, ages and positions seem hardly compatible with the presence of a significant dark matter component, as expected in the $\\Lambda$ CDM scheme. Indeed, if Fornax would have a CDM halo with a standard density profile, all its globular clusters should ...

  8. Trypanosoma evansi and surra: a review and perspectives on origin, history, distribution, taxonomy, morphology, hosts, and pathogenic effects.

    Science.gov (United States)

    Desquesnes, Marc; Holzmuller, Philippe; Lai, De-Hua; Dargantes, Alan; Lun, Zhao-Rong; Jittaplapong, Sathaporn

    2013-01-01

    Trypanosoma evansi, the agent of "surra," is a salivarian trypanosome, originating from Africa. It is thought to derive from Trypanosoma brucei by deletion of the maxicircle kinetoplastic DNA (genetic material required for cyclical development in tsetse flies). It is mostly mechanically transmitted by tabanids and stomoxes, initially to camels, in sub-Saharan area. The disease spread from North Africa towards the Middle East, Turkey, India, up to 53° North in Russia, across all South-East Asia, down to Indonesia and the Philippines, and it was also introduced by the conquistadores into Latin America. It can affect a very large range of domestic and wild hosts including camelids, equines, cattle, buffaloes, sheep, goats, pigs, dogs and other carnivores, deer, gazelles, and elephants. It found a new large range of wild and domestic hosts in Latin America, including reservoirs (capybaras) and biological vectors (vampire bats). Surra is a major disease in camels, equines, and dogs, in which it can often be fatal in the absence of treatment, and exhibits nonspecific clinical signs (anaemia, loss of weight, abortion, and death), which are variable from one host and one place to another; however, its immunosuppressive effects interfering with intercurrent diseases or vaccination campaigns might be its most significant and questionable aspect. PMID:24024184

  9. Trypanosoma evansi and Surra: A Review and Perspectives on Origin, History, Distribution, Taxonomy, Morphology, Hosts, and Pathogenic Effects

    Directory of Open Access Journals (Sweden)

    Marc Desquesnes

    2013-01-01

    Full Text Available Trypanosoma evansi, the agent of “surra,” is a salivarian trypanosome, originating from Africa. It is thought to derive from Trypanosoma brucei by deletion of the maxicircle kinetoplastic DNA (genetic material required for cyclical development in tsetse flies. It is mostly mechanically transmitted by tabanids and stomoxes, initially to camels, in sub-Saharan area. The disease spread from North Africa towards the Middle East, Turkey, India, up to 53° North in Russia, across all South-East Asia, down to Indonesia and the Philippines, and it was also introduced by the conquistadores into Latin America. It can affect a very large range of domestic and wild hosts including camelids, equines, cattle, buffaloes, sheep, goats, pigs, dogs and other carnivores, deer, gazelles, and elephants. It found a new large range of wild and domestic hosts in Latin America, including reservoirs (capybaras and biological vectors (vampire bats. Surra is a major disease in camels, equines, and dogs, in which it can often be fatal in the absence of treatment, and exhibits nonspecific clinical signs (anaemia, loss of weight, abortion, and death, which are variable from one host and one place to another; however, its immunosuppressive effects interfering with intercurrent diseases or vaccination campaigns might be its most significant and questionable aspect.

  10. Mapping the distribution of the main host for plague in a complex landscape in Kazakhstan with an object-based approach using SPOT-5 XS, Landsat 7 ETM+, SRTM and multiple Random Forests

    NARCIS (Netherlands)

    Wilschut, L.I.; Addink, E.A.; Heesterbeek, J.A.P.; Davis, S.A.; Laudisoit, A.; Begon, M.; Atshabar, B.B.; Jong, S.M. de; Burdelov, L.A.; Dubyanskiy, V.M.

    2013-01-01

    Plague is a zoonotic infectious disease present in great gerbil populations in Kazakhstan. Infectious disease dynamics are influenced by the spatial distribution of the carriers (hosts) of the disease. The great gerbil, the main host in our study area, lives in burrows, which can be recognized on hi

  11. Synergistic Effect of Tetraaryl Porphyrins Containing Corannulene and Other Polycyclic Aromatic Fragments as Hosts for Fullerenes. Impact of C60 in a Statistically Distributed Mixture of Atropisomers.

    Science.gov (United States)

    Álvarez, Celedonio M; Barbero, Héctor; Ferrero, Sergio; Miguel, Daniel

    2016-07-15

    Symmetric meso-tetraarylporphyrins bearing phenanthrene, pyrene, and corannulene moieties in meta positions have been synthesized in a straightforward procedure under microwave irradiation by quadruple Suzuki-Miyaura reactions. Their (1)H NMR spectra showed the typical pattern of four atropisomers distributed according to their statistical ratio not properly separable due to their fast isomerization. Their ability to bind buckminsterfullerene has been tested with the whole mixture, and different behaviors have been found, α4 isomer corannulene-substituted porphyrins being the best hosts in the family. PMID:27309203

  12. Bioactivity of fungal endophytes as a function of endophyte taxonomy and the taxonomy and distribution of their host plants.

    Directory of Open Access Journals (Sweden)

    Sarah J Higginbotham

    Full Text Available Fungal endophytes--fungi that grow within plant tissues without causing immediate signs of disease--are abundant and diverse producers of bioactive secondary metabolites. Endophytes associated with leaves of tropical plants are an especially exciting and relatively untapped source of novel compounds. However, one major challenge in drug discovery lies in developing strategies to efficiently recover highly bioactive strains. As part of a 15-year drug discovery project, foliar endophytes were isolated from 3198 plant samples (51 orders, 105 families and at least 232 genera of angiosperms and ferns collected in nine geographically distinct regions of Panama. Extracts from culture supernatants of >2700 isolates were tested for bioactivity (in vitro percent inhibition of growth, % IG against a human breast cancer cell line (MCF-7 and the causative agents of malaria, leishmaniasis, and Chagas' disease. Overall, 32.7% of endophyte isolates were highly active in at least one bioassay, including representatives of diverse fungal lineages, host lineages, and collection sites. Up to 17% of isolates tested per assay were highly active. Most bioactive strains were active in only one assay. Fungal lineages differed in the incidence and degree of bioactivity, as did fungi from particular plant taxa, and greater bioactivity was observed in endophytes isolated from plants in cloud forests vs. lowland forests. Our results suggest that using host taxonomy and forest type to tailor plant collections, and selecting endophytes from specific orders or families for cultivation, will markedly increase the efficiency and efficacy of discovering bioactive metabolites for particular pharmaceutical targets.

  13. A~simple model for predicting the global distribution of the N2 fixing host genus Alnus Mill.: impact of climate change on the global distribution in 2100

    Directory of Open Access Journals (Sweden)

    A. Sakalli

    2013-08-01

    Full Text Available The importance of N2-fixing plants has increased in last decades. Alnus (alder is an important plant group because of its nitrogen fixation ability. Alders are generally distributed in humid locations of boreal, temperate and tropical climate zones, where the nitrogen fixation is an important nitrogen source for other plants. To model the nitrogen fixation by alder, data about the global distribution of alder is absolutely required. In this study a new method and model to predict the distribution of N2-fixing genus on global scale is presented. Three linear functions were defined for the determination of climate area of alder locations. The distribution model was improved with the aid of the soil units from FAO-Unesco Soil Database, and vegetation types from Schmithüsen's biogeographical atlas. The model (Alnus-Distribution-Model, ADM was also developed to predict the impact of climate change on alder distribution by using climate data of five relevant climate models (PCM, ECHam4, HadCM3, CSIRO2 and CGCM2, and four IPCC climate scenarios (i.e. A1FI, A2, B1 and B2 in 2100. The model covered basic approaches to understand the climate change effect on plant migration in the future.

  14. Distribution of freshwater snails in the river Niger basin in Mali with special reference to the intermediate hosts of schistosomes

    DEFF Research Database (Denmark)

    Madsen, Henry; Coulibaly, Godefroy; Furu, Peter

    1987-01-01

    densities appeared to be associated with human water contact activities, which apparently create favourable biotopes for the snails. This is probably due to an alteration of the vegetation and an increase of the trophic status of the site by contamination with food remnants and other debris. The larger...... irrigation canals or lakes in these schemes play an important role in the transmission of human schistosomes and transmission appears to be very focal in these habitats. Infected snails are almost exclusively found in well-defined human water contact sites (WCS). Local infection rates with schistosomes were......Snail surveys were carried out in various parts of Mali. All areas surveyed are part of the Niger basin being either affluents or irrigation schemes fed by this river. The snail species present varied greatly between areas. The following potential hosts of schistosomes were recorded: Biomphalaria...

  15. Association and host selectivity in multi-host pathogens.

    Directory of Open Access Journals (Sweden)

    José M Malpica

    Full Text Available The distribution of multi-host pathogens over their host range conditions their population dynamics and structure. Also, host co-infection by different pathogens may have important consequences for the evolution of hosts and pathogens, and host-pathogen co-evolution. Hence it is of interest to know if the distribution of pathogens over their host range is random, or if there are associations between hosts and pathogens, or between pathogens sharing a host. To analyse these issues we propose indices for the observed patterns of host infection by pathogens, and for the observed patterns of co-infection, and tests to analyse if these patterns conform to randomness or reflect associations. Applying these tests to the prevalence of five plant viruses on 21 wild plant species evidenced host-virus associations: most hosts and viruses were selective for viruses and hosts, respectively. Interestingly, the more host-selective viruses were the more prevalent ones, suggesting that host specialisation is a successful strategy for multi-host pathogens. Analyses also showed that viruses tended to associate positively in co-infected hosts. The developed indices and tests provide the tools to analyse how strong and common are these associations among different groups of pathogens, which will help to understand and model the population biology of multi-host pathogens.

  16. Giant Broad Line Regions in Dwarf Seyferts

    CERN Document Server

    Devereux, Nick

    2015-01-01

    High angular resolution spectroscopy obtained with the Hubble Space Telescope (HST) has revealed a remarkable population of galaxies hosting dwarf Seyfert nuclei with an unusually large broad-line region (BLR). These objects are remarkable for two reasons. Firstly, the size of the BLR can, in some cases, rival those seen in the most luminous quasars. Secondly, the size of the BLR is not correlated with the central continuum luminosity, an observation that distinguishes them from their reverberating counterparts. Collectively, these early results suggest that non-reverberating dwarf Seyferts are a heterogeneous group and not simply scaled versions of each other. Careful inspection reveals broad H Balmer emission lines with single peaks, double peaks, and a combination of the two, suggesting that the broad emission lines are produced in kinematically distinct regions centered on the black hole (BH). Because the gravitational field strength is already known for these objects, by virtue of knowing their BH mass, ...

  17. Globular clusters as tracers of the host galaxy mass distribution: the Fornax dSph test case

    CERN Document Server

    Arca-Sedda, Manuel

    2016-01-01

    The Fornax dwarf spheroidal galaxy is the most massive satellites of the Milky Way, claimed to be embedded in a huge dark matter halo, and the only among the Milky Way satellites hosting five globular clusters. Interestingly, their estimated masses, ages and positions seem hardly compatible with the presence of a significant dark matter component, as expected in the $\\Lambda$ CDM scheme. Indeed, if Fornax would have a CDM halo with a standard density profile, all its globular clusters should have sunk to the galactic centre many Gyr ago due to dynamical friction. Due to this, some authors proposed that the most massive clusters may have formed out of Fornax and later tidally captured. In this paper we investigate the past evolution of the Fornax GC system by using both a recently developed, semi-analytical treatment of dynamical friction and direct $N$-body simulations of the orbital evolution of the globular clusters within Fornax and of Fornax galaxy around the Milky Way. Our results suggest that an "in-sit...

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

    OpenAIRE

    K. N. de Kock; C. T. Wolmarans

    2008-01-01

    Account is given of the distribution and habitats of the three Lymnaea species currently on recordin the National Freshwater Snail Collection (NFSC) of South Africa. A total number of 616, 353and 202 loci (1/16th square degrees) was respectively recorded for Lymnaea natalensis, L. columellaand L. truncatula. The number of loci in which the collection sites of each species was located, wasdistributed in intervals of mean annual air temperature and rainfall, as well as intervals of meanaltitude...

  19. Globular clusters as tracers of the host galaxy mass distribution: the Fornax dSph test case

    Science.gov (United States)

    Arca-Sedda, M.; Capuzzo-Dolcetta, R.

    2016-10-01

    The Fornax dwarf spheroidal galaxy is the most massive satellites of the Milky Way, claimed to be embedded in a huge dark matter halo, and the only among the Milky Way satellites hosting five globular clusters. Interestingly, their estimated masses, ages and positions seem hardly compatible with the presence of a significant dark matter component, as expected in the ΛCDM scheme. Indeed, if Fornax would have a CDM halo with a standard density profile, all its globular clusters should have sunk to the galactic centre many Gyr ago due to dynamical friction. Due to this, some authors proposed that the most massive clusters may have formed out of Fornax and later tidally captured. In this paper, we investigate the past evolution of the Fornax GC system by using both a recently developed, semi-analytical treatment of dynamical friction and direct N-body simulations of the orbital evolution of the globular clusters within Fornax and of Fornax galaxy around the Milky Way. Our results suggest that an `in situ' origin for all the clusters is likely if their observed positions are close to their spatial ones and their orbits are almost circular. Moreover, the Milky Way seems to accelerate the GC decay reducing the decay time of 15 per cent. Nevertheless, our results indicate that the GCs survival probability exceeds 50 per cent, even in the case of cuspy density profiles. We conclude that more detailed data are required to shed light on the Fornax dark matter content, to distinguish between a cuspy or a cored profile.

  20. The distribution of Mekong schistosomiasis, past and future: preliminary indications from an analysis of genetic variation in the intermediate host.

    Science.gov (United States)

    Attwood, Stephen W; Fatih, Farrah A; Campbell, Ian; Upatham, E Suchart

    2008-09-01

    Neotricula aperta is the only known intermediate host of Schistosoma mekongi which infects humans in Cambodia and the southern tip of Lao PDR. DNA-sequence data (partial rrnL, i.e., mitochondrial 16S large ribosomal-RNA gene) were obtained for 359 N. aperta snails sampled at 31 localities in Cambodia, Lao PDR and Thailand. A nested clade analysis was performed to detect and evaluate any geographical patterns in the observed variation and to identify genetic subpopulations or clades. Coalescent simulations were used to compare different historical biogeographical hypotheses for N. aperta and S. mekongi. A coalescent based method was also used to provide maximum likelihood estimates (MLEs) for effective populations sizes and historical growth and migration rates. Dates were also estimated for phylogenetic events on the gene tree reconstructed for the sampled haplotypes (e.g. the time to most recent common ancestor). N. aperta was found to be divided into two monophyletic clades, a spring-dwelling form of northern Lao PDR and a more widespread larger-river dwelling form of southern Lao PDR and Cambodia; this divergence was dated at 9.3 Ma. The populations with the largest estimated population sizes were found in the Mekong River of Lao PDR and Cambodia; these, together with those of the rivers of eastern Cambodia, appeared to have been the fastest growing populations. Dominant levels of gene-flow (migration) were apparent in a South to North direction, particularly out of seeder populations in the Cambodian Mekong River. The radiation of N. aperta into sub-clades across Cambodia and Lao PDR is dated at around 5 Ma. The findings suggest that historical events, rather than ecology, might best explain the absence of S. mekongi from most of Lao PDR. The public health implications of these findings are discussed, as are pointers for future studies and surveillance. PMID:18499512

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

    Directory of Open Access Journals (Sweden)

    Simren Brar

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

  2. Gonapodasmius epinepheli observed in cage cultured orange spotted grouper (Epinephelus coioides in Southern Thailand: geographical distribution of parasite and host response

    Directory of Open Access Journals (Sweden)

    Kidchakan Supamattaya

    2008-03-01

    Full Text Available Gonapodasmius epinepheli Abdul-Salam, Sreelatha & Farah, 1990, a didymozoid trematode, was found in orange spotted grouper (Epinephelus coioides, Hamilton, 1822 cultured in cages in Southern Thailand, both on the east coast (Gulf of Thailand and the west coast (Indian Ocean. The parasite encysted on the primary lamellae of the gills. Histological sections revealed that larvae were primarily embedded underneath the gill epithelium and eggs of the parasite were distributed in some organs such as gill epithelium, heart and macrophage centers in the head kidney. Pathological changes and host response were shown mainly on gill lamellae, e.g. reduction and destruction of secondary lamellae. Prevalence of parasite and its life cycle are discussed in this report.

  3. Distribution, host specificity, and the potential for cryptic speciation in hoverfly Microdon myrmicae (Diptera: Syrphidae), a social parasite of Myrmica ants

    DEFF Research Database (Denmark)

    Bonelli, Simona; Witek, Magdalena; Canterino, Sara;

    2011-01-01

    least the western Palaearctic. 2. Current knowledge of the European distributions of both Microdon myrmicae and Microdon mutabilis in Europe is reviewed. Also, in detailed studies of two Polish populations, Microdon myrmicae was found to survive equally well with two Myrmica ant species. We examine...... relative to its host ants. 4. In two populations Myrmica scabrinodis and Myrmica gallienii are both abundant and rear Microdon myrmicae in equal proportions. Microdon myrmicae pupae from Myrmica gallienii nests were heavier and the anterior respiratory organs were of significantly different shape. In......1. In 2002 Microdon myrmicae, a social parasite of Myrmica ants, was taxonomically separated from Microdon mutabilis. The original study in the U.K. found Microdon myrmicae to be specific to one ant species, Myrmica scabrinodis, yet it became apparent that the range of Microdon myrmicae includes at...

  4. Spatial distribution of Aglais urticae (L.) and its host plant Urtica dioica (L.) in an agricultural landscape: implications for Bt maize risk assessment and post-market monitoring.

    Science.gov (United States)

    Gathmann, Achim; Wirooks, Ludger; Eckert, Jörg; Schuphan, Ingolf

    2006-01-01

    Over the past decades, genes of Bacillus thuringiensis var. kurstaki (Berliner) (Bt) coding for protein toxins have been engineered into maize for protection against the European Corn Borer (Ostrinia nubilalis (Hbn.)). However, these transgenic plants may have an impact on non-target organisms. In particular, a potential hazard was identified for non-target lepidopteran larvae, if they consume Bt maize pollen on their host plants. Risk can be defined as a function of the effect of an event (hazard) and the likelihood of this event occurring. Although data on toxicity (hazard) are available from many lab and field studies, knowledge about the environmental exposure of European lepidopteran larvae is incomplete at the population level. Therefore we studied the distribution of small tortoiseshell caterpillars (Aglais urticae (L.)) and its host plant in an agricultural landscape in Germany, to estimate the potential population exposure to maize pollen. The results showed that larvae of the small tortoiseshell developed primarily on freshly sprouted nettle stands (Urtica dioica (L.)) in field margins, rather than adjacent to hedges and groves. However, the main distribution was at margins of cereal (non-maize) fields, where 70% of all larvae were found. This may be due the fact that cereals covered 54% of the survey area, while maize only covered 6.1%. On the other hand, maize fields seem so show higher food plant densities than cereal crops. The results must be interpreted carefully, as the data basis of the present study is very small, and the situation can vary between years due to crop rotation or other changes in agricultural practices. Therefore it is still questionable whether the small tortoiseshell is significantly exposed to maize pollen. For a conclusive risk assessment, more replications and surveys of larger areas in different intensively managed agricultural landscapes over several years are needed. PMID:16978572

  5. Influencing factors of distribution of Trichinella larvae in host muscles%旋毛虫幼虫在宿主肌组织中分布的影响因素

    Institute of Scientific and Technical Information of China (English)

    李立宏; 姜文静

    2012-01-01

    The distribution states of Trichinella spimlis larvae in host muscles are very complicated, and they are possibly in-fluenced by many factors, such as host species, the physiological condition of host muscles, Trichinella species, the encapsulat-ing condition of Trichinella spiralis encapsulated larvae, the level of infection and others. This paper summarizes the advance in the study of the influencing factors of distribution of Trichinella spiralis encapsulated larvae in host muscles.%旋毛虫幼虫在宿主肌组织中的分布受多种因素的影响,如宿主种类、肌肉生理状况、旋毛虫种别、旋毛虫幼虫能否成囊、感染量等.本文对旋毛虫幼虫在宿主肌组织分布的影响因素作一综述.

  6. [Migration and distribution of allogeneic T lymphocytes in organs of graft-versus-host disease mouse model].

    Science.gov (United States)

    Wen, Hong-Sheng; Wang, Jian-Min; Zhou, Hong; Xia, Rong; Qiu, Hui-Ying; Gao, Lei; Hu, Xiao-Xia

    2006-10-01

    This study was aimed to investigate the migration and distribution processes of allogeneic donor T lymphocytes in the organs of recipient mice. GVHD model was established by transfusion of the splenocytes of eGFP transgeneic C57BL/6 mice together with born marrow cells harvested from C57BL/6 mice into BALB/c mice underwent 8.0 Gy total body irradiation. The migration and homing of eGFP(+) cells were tracked by stereo-fluorescent microscopy or inverted fluorescent microscopy and flow cytometry. The enzyme linked immunosorbent assay (ELISA) was performed on supernatants from the tissue homogenates to detect the amount of MIP-1alpha. The results indicated that GVHD clinical manifestation and pathological changes of organs appeared on day 8 post transplantation. eGFP-positive donor T cells in recipient organs were observed by inverted fluorescence microscope in frozen section, or by stereo-fluorescence microscopy in living organs, such as liver, spleen, skin, lungs, bowels, and tongue. The highest expression of MIP-1alpha was on day 7 post transplantation in the liver (491.3 +/- 32.1 pg/ml), and day 3 post transplantation in the spleen (881.5 +/- 45.2 pg/ml), respectively (P liver, skin, bowels, as well as lungs and tongue. MIP-1alpha may be in relation with the infiltration of T lymphocytes in liver and spleen.

  7. Host-parasite relationships and geographic distribution of Salmincola corpulentus (Copepoda: Lernaeopodidae) on bloater (Coregonus hoyi) stocks in Lake Huron

    Science.gov (United States)

    Bowen, Charles A.; Stedman, Ralph M.

    1990-01-01

    Examination of the branchial cavities of 8347 adult bloaters (Coregonus hoyi) collected from seven locations in Lake Huron for parasitic copepods yielded only the lernaeopodid Salmincola corpulentus; its distribution was limited to bloaters collected in the southern two-thirds of the lake. The infections were highest off Au Sable Point and on Six Fathom Bank, where 12 and 22%, of the bloaters examined were infected, respectively. All copepods seen were sexually mature females. The dorsal anterior portion of the branchial rim was the preferred site of attachment. The prevalence of S. corpulentus increased with length of the bloaters, reaching a maximum of 40% in fish longer than 330 mm; none were seen in bloaters shorter than 182 mm. The mean intensity of S. corpulentus was unusually low (1.0–1.9) for a lernaeopodid copepod and the maximum number of copepods found on a single bloater was five. Prevalences of copepods differed significantly (P < 0.05) between bloaters collected at different geographic locations, suggesting that S. corpulentus may be of value in bloater stock determination.

  8. Fourier evaluation of broad Moessbauer spectra

    International Nuclear Information System (INIS)

    It is shown by the Fourier analysis of broad Moessbauer spectra that the even part of the distribution of the dominant hyperfine interaction (hyperfine field or quadrupole splitting) can be obtained directly without using least-square fitting procedures. Also the odd part of this distribution correlated with other hyperfine parameters (e.g. isomer shift) can be directly determined. Examples for amorphous magnetic and paramagnetic iron-based alloys are presented. (author)

  9. Correlation between genotypes of tRNA-linked short tandem repeats in Entamoeba nuttalli isolates and the geographical distribution of host rhesus macaques.

    Science.gov (United States)

    Feng, Meng; Komiyama, Tomoyoshi; Yanagi, Tetsuo; Cheng, Xunjia; Sherchand, Jeevan B; Tachibana, Hiroshi

    2014-01-01

    Several polymorphic markers, including serine-rich protein genes, have been used for the genotyping of isolates from the morphologically indistinguishable protozoan parasites Entamoeba histolytica, Entamoeba dispar, and Entamoeba nuttalli. Genotypes of tRNA-linked short tandem repeats (STRs) are highly polymorphic, but the correlation with geographical distribution is unknown. We have recently isolated 15 E. nuttalli strains from wild rhesus macaques in four locations in Kathmandu Valley, Nepal. The sequences of the serine-rich protein genes of the E. nuttalli strains differed among the four locations. In this study, we analyzed tRNA-linked STRs in six loci of the 15 strains. Two genotypes were found in loci N-K2, R-R, and S(TGA)-D, three in locus S-Q, and five in locus D-A. In locus A-L, one major genotype and ten minor genotypes were found, resulting in mixtures of two to six genotypes in eight strains. By combination of the main genotypes in the six loci, the 15 strains were divided into nine genotypes. The genotypes observed in E. nuttalli strains were quite different from those in E. histolytica and E. dispar. A phylogenetic tree constructed from tRNA-linked STRs in the six loci reflected the different places of isolation. These results suggest that sequence diversity of tRNA-linked STRs in E. nuttalli occurs with relatively high frequency and might be a marker of geographical distribution of host rhesus macaques, even in limited areas.

  10. Viral and bacterial production in the North Water: in situ measurements, batch-culture experiments and characterization and distribution of a virus host system

    Science.gov (United States)

    Middelboe, Mathias; Nielsen, Torkel G.; Bjørnsen, Peter K.

    Growth and viral lysis of bacterioplankton at subzero temperatures were measured in the North Water polynya in July 1998. In situ measurements of bacterial carbon consumption in surface waters ranged from 15 to 63 μg C l -1 d -1 in the eastern and 6 to 7 μg C l -1 d -1 in the northern part of the polynya. Both bacterial abundance and activity appeared to increase in response to the decay of the phytoplankton bloom that developed in the North Water. Organic carbon was the limiting substrate for bacteria in the polynya since addition of glucose, but not inorganic nutrients, to batch cultures increased both the carrying capacity of the substrate and the growth rate of the bacteria. Bacterial growth rates ranged from 0.11 to 0.40 d -1, corresponding to bacterial generation times of 1.7-6.3 d. The in situ viral production rate was estimated both from the frequency of visibly infected cells and from the rate of viral production in batch cultures; it ranged from 0.04 to 0.52 d -1 and from 0.25 to 0.47 d -1, respectively. From 6% to 28% of bacterial production was found to be lost due to viral lysis. The average virus-bacteria ratio was 5.1±3.1, with the abundance of viruses being correlated positively with bacterial production. A Pseudoalteromonas sp. bacterial host and an infective virus were isolated from the polynya; characteristics and distribution of the virus-host system were examined. The Pseudoalteromonas sp. showed psychrotolerant growth and sustained significant production of viruses at 0°C. The virus-host system was found throughout the polynya. Overall the results suggested that a large amount of organic carbon released during the development and breakdown of the spring phytoplankton bloom was consumed by planktonic bacteria and that the microbial food web was an important and dynamic component of the planktonic food web in the North Water.

  11. Combining a climatic niche model of an invasive fungus with its host species distributions to identify risks to natural assets: Puccinia psidii Sensu Lato in Australia.

    Directory of Open Access Journals (Sweden)

    Darren J Kriticos

    Full Text Available Puccinia psidii sensu lato (s.l. is an invasive rust fungus threatening a wide range of plant species in the family Myrtaceae. Originating from Central and South America, it has invaded mainland USA and Hawai'i, parts of Asia and Australia. We used CLIMEX to develop a semi-mechanistic global climatic niche model based on new data on the distribution and biology of P. psidii s.l. The model was validated using independent distribution data from recently invaded areas in Australia, China and Japan. We combined this model with distribution data of its potential Myrtaceae host plant species present in Australia to identify areas and ecosystems most at risk. Myrtaceaeous species richness, threatened Myrtaceae and eucalypt plantations within the climatically suitable envelope for P. psidii s.l in Australia were mapped. Globally the model identifies climatically suitable areas for P. psidii s.l. throughout the wet tropics and sub-tropics where moist conditions with moderate temperatures prevail, and also into some cool regions with a mild Mediterranean climate. In Australia, the map of species richness of Myrtaceae within the P. psidii s.l. climatic envelope shows areas where epidemics are hypothetically more likely to be frequent and severe. These hotspots for epidemics are along the eastern coast of New South Wales, including the Sydney Basin, in the Brisbane and Cairns areas in Queensland, and in the coastal region from the south of Bunbury to Esperance in Western Australia. This new climatic niche model for P. psidii s.l. indicates a higher degree of cold tolerance; and hence a potential range that extends into higher altitudes and latitudes than has been indicated previously. The methods demonstrated here provide some insight into the impacts an invasive species might have within its climatically suited range, and can help inform biosecurity policies regarding the management of its spread and protection of valued threatened assets.

  12. Broad spectrum antibiotic compounds and use thereof

    Energy Technology Data Exchange (ETDEWEB)

    Koglin, Alexander; Strieker, Matthias

    2016-07-05

    The discovery of a non-ribosomal peptide synthetase (NRPS) gene cluster in the genome of Clostridium thermocellum that produces a secondary metabolite that is assembled outside of the host membrane is described. Also described is the identification of homologous NRPS gene clusters from several additional microorganisms. The secondary metabolites produced by the NRPS gene clusters exhibit broad spectrum antibiotic activity. Thus, antibiotic compounds produced by the NRPS gene clusters, and analogs thereof, their use for inhibiting bacterial growth, and methods of making the antibiotic compounds are described.

  13. 帽儿山天然次生林主要阔叶树种叶量分布模拟%Simulation of Foliage Distribution for Major Broad-Leaved Species in Secondary Forest in Mao'er Mountain

    Institute of Scientific and Technical Information of China (English)

    卢军; 李凤日; 张会儒; 张守攻

    2011-01-01

    The spatial distribution of foliage is the fundamental composition of crown structure, moreover, it is convenient to understand the mechanism of the energy convert to biomass above-ground through the crown by evaluating the spatial distribution of foliage and researching the relationship between foliage and factors in individual trees and stand. In Mao' er Mountains of Heilongjiang Province, 30 permanent sample plots in secondary forest were established where 3 401 biomass of living branches from 176 stem analysis sample trees with 10 different broad-leaved species were measured, 2007. This study presents 10 individual tree models for the prediction of vertical distribution of living crown. The 3 parameters Chapman-Richards model was used to estimate the distribution of the crown biomasses between the lower and upper limits of the crown. In the models for the relative cumulative living crown, parameters estimate results show that all coefficiens of determination are high more than 0. 91 especially 0. 98 for birch. The highest relative height at which the foliage reached its maximum point was 0. 82 CL( crown length) for manchurian ash and the lowest was 0. 52 CL for cork tree. The peak points for other species were between these two values, e. G. 0. 66 CL for birch and 0. 78 CL for oak. The percentage of foliage for broad-leaved species in secondary forestry at the top crown (above 0. 3 CL)was very small, which in middle crown and below it(0. 4 CL -0. 8 CL)took about 60% -70% of total biomass, especially 72. 22% for birch, 72. 55% for poplar and the minimum was 57. 51% for manchurian ash, however at under-part of the crown for all species occupied about 10% of total foliage. The models can be used for the planning of harvesting operations, for the selection of feasible harvesting methods, and for the estimation of nutrient removals of different harvesting practices.%2007年,在黑龙江省帽儿山林区,设置30块天然次生林固定标准地,获取10

  14. New location for Bulinus truncatus (Audouin, 1827 (Gastropoda: Planorbidae intermediate host of Schistosoma haematobium and its distribution in the Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Dana, Elías D.

    2015-12-01

    Full Text Available This paper reports a new population of Bulinus truncatus (Audouin, 1827 (Gastropoda, Planorbidae found in the province of Almería (Southeast Spain. B. truncatus is an intermediate host of Schistosoma haematobium, the trematode which causes urinary schistosomiasis in humans. Individuals were identified to species level by double-nested PCR, resulting in 100% homology. This population is located under the driest climate conditions of the Iberian Peninsula. Data on the distribution of this species in the Iberian Peninsula was gathered and is provided in this paper. Improved knowledge of the distribution of Bulinus truncatus is key to assess the risk of new outbreaks of schistosomiasis in the Iberian Peninsula.En este trabajo se reporta una nueva población de Bulinus truncatus (Audouin, 1827 (Gastropoda, Planorbidae en la provincia de Almería (Sureste de España. Se trata de una especie que presenta considerable interés tanto zoológico como epidemiológico por su papel como hospedador intermediario de Schistosoma haematobium, responsable de la esquistosomiasis urogenital humana. Los ejemplares fueron determinados a nivel específico mediante PCR doble anidada, con un 100% de homología. Se trata de la población localizada más al Sureste y en condiciones de mayor aridez en la península Ibérica. Se recopilaron los datos de presencia publicados para conocer su distribución en la península. El conocimiento de la distribución de Bulinus truncatus es una pieza clave para evaluar el riesgo de nuevos focos de esquistosomiasis en la península Ibérica.

  15. Distribution of metals in the termite Tumulitermes tumuli (Froggatt: two types of Malpighian tubule concretion host Zn and Ca mutually exclusively.

    Directory of Open Access Journals (Sweden)

    Aaron D Stewart

    Full Text Available The aim of this study was to determine specific distribution of metals in the termite Tumulitermes tumuli (Froggatt and identify specific organs within the termite that host elevated metals and therefore play an important role in the regulation and transfer of these back into the environment. Like other insects, termites bio-accumulate essential metals to reinforce cuticular structures and utilize storage detoxification for other metals including Ca, P, Mg and K. Previously, Mn and Zn have been found concentrated in mandible tips and are associated with increased hardness whereas Ca, P, Mg and K are accumulated in Malpighian tubules. Using high resolution Particle Induced X-Ray Emission (PIXE mapping of whole termites and Scanning Electron Microscope (SEM Energy Dispersive X-ray (EDX spot analysis, localised accumulations of metals in the termite T. tumuli were identified. Tumulitermes tumuli was found to have proportionally high Mn concentrations in mandible tips. Malpighian tubules had significant enrichment of Zn (1.6%, Mg (4.9%, P (6.8%, Ca (2.7% and K (2.4%. Synchrotron scanning X-ray Fluorescence Microprobe (XFM mapping demonstrated two different concretion types defined by the mutually exclusive presence of Ca and Zn. In-situ SEM EDX realisation of these concretions is problematic due to the excitation volume caused by operating conditions required to detect minor amounts of Zn in the presence of significant amounts of Na. For this reason, previous researchers have not demonstrated this surprising finding.

  16. Leaf morphological and anatomical characteristics of epiphytes and their host tress in lower subtropical evergreen broad-leaved forest%南亚热带常绿阔叶林林冠层附生植物及其宿主叶片的形态解剖特征

    Institute of Scientific and Technical Information of China (English)

    江浩; 黄钰辉; 周国逸; 胡晓颖; 刘世忠; 唐旭利

    2011-01-01

    Canopy-dwelling epiphytic plants have been well characterized in terms of the physiological and morphological traits permitting them to thrive in the absence of access to the soil. The ultimate purpose of this paper is to characterize the morphological and anatomical characteristics of major canopy-dwelling epiphytic plants and their host trees in the lower subtropical evergreen broad-leaved forest in the Southern China. Results showed epiphytic plants differed from host trees on leaf morphology and anatomy. Compared with host trees, epiphytic plants have smaller leaf area, larger specific leaf area (SLA), higher leaf water content, higher leaf thickness, higher leaf abaxial and adaxial epidermis thickness, lower stomatal density and stomata size for the uptake and restore of water and nutrients. Difference of leaf morphological and anatomical characters between epiphytes can be largely explained by changes of environmental factors such as photosynthetically active radiation (PAR), temperature and humidity within forest canopy. D. Chinensis and P. Serpens showed special characteristics with high leaf water contents, low stomatal density, thick spongy tissues and thin palisade tissues to adapt to their upper dwelling environment (high temperature, low air humidity and high PAR). F. Glaucescens and P. Hancei have large leaf area, thin leaf, and high stomata size in acclimatizing to the low temperature, high air humidity and low PAR.%选择南亚热带常绿阔叶林中具有代表性的4种林冠层附生植物:白背瓜馥木(Fissistigma glaucescens)、瓜子金(Dischidia chinensis)、蔓九节(Psychotria serpens)、山蒌(Piper hancei)及其主要宿主植物:厚壳桂(Cryptocarya chinensis)、荷木(Schimasuperba)、华润楠(Machilus chinensis)、锥栗(Castanopsis chinensis)为研究对象,对其叶片形态结构和解剖结构特征进行比较.研究结果表明:宿主植物与附生植物的叶片形态结构差异显著.相对于4种宿主植物,4种附生

  17. Invasive Bruchid species Bruchidius siliquastri Delobel, 2007 and Megabruchidius tonkineus (Pic, 1914) (Insecta: Coleoptera: Chrysomelidae: Bruchinae) new in the fauna of Serbia: Review of the distribution, biology and host plants

    OpenAIRE

    Gavrilović, Bojan; Savić, Dragiša

    2013-01-01

    Two invasive bruchid species - Bruchidius siliquastri Delobel, 2007 and Megabruchidius tonkineus (Pic, 1914) - found on Mt. Fruška Gora during 2011 and 2012 were recorded for the first time in Serbian fauna. Originating from Asia, these beetles were accidentally introduced into Europe. Data on their introduction into Serbia, distribution, biology and host plant associations are presented and discussed.

  18. Linking spatially distributed biogeochemical data with a two-host life-cycle pathogen:A model of whirling disease dynamics in salmonid fishes in the Intermountain West

    Science.gov (United States)

    Fytilis, N.; Lamb, R.; Stevens, L.; Morrissey, L. A.; Kerans, B.; Rizzo, D. M.

    2010-12-01

    and then compared the resulting groups to site-specific worm community structures. The SOM mined patterns from this highly dimensional data and produced 2-D visualizations of the data clusters. This process, in concert with iterative feedback with stream ecologists, led to the adaptation of new nonlinear relations and suggests new subsets of input parameters that guide the next round of SOM simulations, expand the pool of concepts, hone existing hypotheses, generate new hypotheses, and so on. The methodologies developed here helped mine the relationship between dominant biogeochemical features and the distribution of an alternative host of a vertebrate disease. This collaboration between modelers, field ecologists and geneticists will prove useful in guiding future data gathering and modeling efforts. (i.e., identifying missing data gaps and sampling frequency), and will enable more effective, high-volume hypothesis generation that, in turn, will better guide complex experimental designs providing integrated understanding of disease dynamics.

  19. Integrating Hot and Cool Intelligences: Thinking Broadly about Broad Abilities

    Directory of Open Access Journals (Sweden)

    W. Joel Schneider

    2016-01-01

    Full Text Available Although results from factor-analytic studies of the broad, second-stratum abilities of human intelligence have been fairly consistent for decades, the list of broad abilities is far from complete, much less understood. We propose criteria by which the list of broad abilities could be amended and envision alternatives for how our understanding of the hot intelligences (abilities involving emotionally-salient information and cool intelligences (abilities involving perceptual processing and logical reasoning might be integrated into a coherent theoretical framework.

  20. A Hubble Space Telescope Survey of the Host Galaxies of Superluminous Supernovae

    CERN Document Server

    Angus, C R; Perley, D A; Tanvir, N R; Lyman, J D; Stanway, E R; Fruchter, A S

    2016-01-01

    We present Hubble Space Telescope (HST) WFC3 UV and near-IR (nIR) imaging of 21 Superluminous Supernovae (SLSNe) host galaxies, providing a sensitive probe of star formation and stellar mass with the hosts. Comparing the photometric and morphological properties of these host galaxies with those of core collapse supernovae (CCSNe) and long-duration gamma-ray bursts (LGRBs), we find SLSN hosts are fainter and more compact at both UV and nIR wavelengths, in some cases we barely recover hosts with absolute magnitude around MV ~ -14. With the addition of ground based optical observations and archival results, we produce spectral energy distribution (SED) fits to these hosts, and show that SLSN hosts possess lower stellar mass and star formation rates. This is most pronounced for the hydrogen deficient Type-I SLSN hosts, although Type-II H-rich SLSN host galaxies remain distinct from the bulk of CCSNe, spanning a remarkably broad range of absolute magnitudes, with ~30% of SLSNe-II arising from galaxies fainter than...

  1. Host manipulation by parasites: a multidimensional phenomenon

    OpenAIRE

    Thomas, F; Poulin, R.; Brodeur, J.

    2010-01-01

    The diversity of ways in which parasites manipulate the phenotype of their hosts to increase their transmission has been well-documented during the past decades. Parasites clearly have the potential to alter a broad range of phenotypic traits in their hosts, extending from behaviour and colour to morphology and physiology. While the vast majority of studies have concentrated on few, often only one, host characters, there is increasing evidence that manipulative parasites alter multiple charac...

  2. The Offset and Host Light Distributions of Long Gamma-Ray Bursts: A New View from HST Observations of Swift Bursts

    CERN Document Server

    Blanchard, Peter K; Fong, Wen-fai

    2015-01-01

    [Abridged] We present the results of an extensive Hubble Space Telescope (HST) imaging study of ~100 Swift long-duration gamma-ray bursts (LGRBs) spanning 0.03 0.6 while bursts at R/R_h > 0.5 uniformly trace the light of their hosts. This indicates that the spatial correlation of LGRB locations with bright star forming regions seen in the full sample is dominated by the contribution from bursts at small offset and that LGRBs in the outer parts of galaxies show no preference for unusually bright star forming regions. We conclude that LGRBs strongly prefer the bright, inner regions of their hosts indicating that the star formation taking place there is more favorable for LGRB progenitor production. This indicates that another environmental factor beyond metallicity, such as binary interactions or IMF differences, may be operating in the central regions of LGRB hosts.

  3. The Broad Autism Phenotype Questionnaire

    Science.gov (United States)

    Hurley, Robert S. E.; Losh, Molly; Parlier, Morgan; Reznick, J. Steven; Piven, Joseph

    2007-01-01

    The broad autism phenotype (BAP) is a set of personality and language characteristics that reflect the phenotypic expression of the genetic liability to autism, in non-autistic relatives of autistic individuals. These characteristics are milder but qualitatively similar to the defining features of autism. A new instrument designed to measure the…

  4. Survey and competition assay data suggest species-specific difference in host/niche adaptation influence the distribution of Fusarium graminearum species complex pathogens in Brazil

    Science.gov (United States)

    The Fusarium graminearum species complex (FGSC) comprises at least 16 toxigenic species of economic concern to cereal crops. In Brazil, six species of the FGSC have been identified, but their frequencies vary according to the host species. Although F. graminearum (Fgra) is dominant in wheat (>90%) a...

  5. Systemic Virus distribution and host responses in brain and intestine of chickens infected with low pathogenic and high pathogenic avian influenza virus

    NARCIS (Netherlands)

    Post, J.; Burt, D.W.; Cornelissen, J.B.W.J.; Broks, V.C.M.; Zoelen, van D.; Peeters, B.P.H.; Rebel, J.M.J.

    2012-01-01

    Background: Avian influenza virus (AIV) is classified into two pathotypes, low pathogenic (LP) and high pathogenic ( HP), based on virulence in chickens. Differences in pathogenicity between HPAIV and LPAIV might eventually be related to specific characteristics of strains, tissue tropism and host r

  6. IPv6 host fingerprint

    OpenAIRE

    Nerakis, Eleftherios

    2006-01-01

    Approved for public release, distribution unlimited This thesis explores ways of using probe packets to identify the type and version of OS that is run by a remote IPv6 host. Such a probing technique can be effective because developers of different OSes often interpret the guidance provided by the RFCs slightly differently, and consequently their network protocol stack implementation may generate responses bearing unique markers to certain probing packets. The key challenge is to find suit...

  7. Broad Diphotons from Narrow States

    CERN Document Server

    An, Haipeng; Zhang, Yue

    2015-01-01

    ATLAS and CMS have each reported a modest diphoton excess consistent with the decay of a broad resonance at ~ 750 GeV. We show how this signal can arise in a weakly coupled theory comprised solely of narrow width particles. In particular, if the decaying particle is produced off-shell, then the associated diphoton resonance will have a broad, adjustable width. We present simplified models which explain the diphoton excess through the three-body decay of a scalar or fermion. Our minimal ultraviolet completion is a weakly coupled and renormalizable theory of a singlet scalar plus a heavy vector-like quark and lepton. The smoking gun of this mechanism is an asymmetric diphoton peak recoiling against missing transverse energy, jets, or leptons.

  8. Cochlear microphonic broad tuning curves

    Science.gov (United States)

    Ayat, Mohammad; Teal, Paul D.; Searchfield, Grant D.; Razali, Najwani

    2015-12-01

    It is known that the cochlear microphonic voltage exhibits much broader tuning than does the basilar membrane motion. The most commonly used explanation for this is that when an electrode is inserted at a particular point inside the scala media, the microphonic potentials of neighbouring hair cells have different phases, leading to cancelation at the electrodes location. In situ recording of functioning outer hair cells (OHCs) for investigating this hypothesis is exceptionally difficult. Therefore, to investigate the discrepancy between the tuning curves of the basilar membrane and those of the cochlear microphonic, and the effect of phase cancellation of adjacent hair cells on the broadness of the cochlear microphonic tuning curves, we use an electromechanical model of the cochlea to devise an experiment. We explore the effect of adjacent hair cells (i.e., longitudinal phase cancellation) on the broadness of the cochlear microphonic tuning curves in different locations. The results of the experiment indicate that active longitudinal coupling (i.e., coupling with active adjacent outer hair cells) only slightly changes the broadness of the CM tuning curves. The results also demonstrate that there is a π phase difference between the potentials produced by the hair bundle and the soma near the place associated with the characteristic frequency based on place-frequency maps (i.e., the best place). We suggest that the transversal phase cancellation (caused by the phase difference between the hair bundle and the soma) plays a far more important role than longitudinal phase cancellation in the broadness of the cochlear microphonic tuning curves. Moreover, by increasing the modelled longitudinal resistance resulting the cochlear microphonic curves exhibiting sharper tuning. The results of the simulations suggest that the passive network of the organ of Corti determines the phase difference between the hair bundle and soma, and hence determines the sharpness of the

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  10. The Swift GRB Host Galaxy Legacy Survey - II. Rest-Frame NIR Luminosity Distribution and Evidence for a Near-Solar Metallicity Threshold

    CERN Document Server

    Perley, D A; Hjorth, J; Laskar, T; Berger, E; Chary, R; Postigo, A de Ugarte; Fynbo, J P U; Krühler, T; Levan, A J; Michałowski, M J; Schulze, S

    2016-01-01

    We present rest-frame NIR luminosities and stellar masses for a large and uniformly-selected population of GRB host galaxies using deep Spitzer Space Telescope imaging of 117 targets from the Swift GRB Host Galaxy Legacy Survey spanning 0.03 2; metals stifle GRB production in most galaxies at z<1.5 but have only minor impact at higher redshifts. The metallicity threshold we infer is much higher than predicted by single-star models and favors a binary progenitor. Our observations also constrain the fraction of cosmic star-formation in low-mass galaxies undetectable to Spitzer to be a small minority at most redshifts (~10% at z~2, ~25% at z~3, and ~50% at z=3.5-6.0).

  11. Mapping the distribution of the main host for plague in a complex landscape in Kazakhstan: An object-based approach using SPOT-5 XS, Landsat 7 ETM+, SRTM and multiple Random Forests.

    Science.gov (United States)

    Wilschut, L I; Addink, E A; Heesterbeek, J A P; Dubyanskiy, V M; Davis, S A; Laudisoit, A; M Begon; Burdelov, L A; Atshabar, B B; de Jong, S M

    2013-08-01

    Plague is a zoonotic infectious disease present in great gerbil populations in Kazakhstan. Infectious disease dynamics are influenced by the spatial distribution of the carriers (hosts) of the disease. The great gerbil, the main host in our study area, lives in burrows, which can be recognized on high resolution satellite imagery. In this study, using earth observation data at various spatial scales, we map the spatial distribution of burrows in a semi-desert landscape. The study area consists of various landscape types. To evaluate whether identification of burrows by classification is possible in these landscape types, the study area was subdivided into eight landscape units, on the basis of Landsat 7 ETM+ derived Tasselled Cap Greenness and Brightness, and SRTM derived standard deviation in elevation. In the field, 904 burrows were mapped. Using two segmented 2.5 m resolution SPOT-5 XS satellite scenes, reference object sets were created. Random Forests were built for both SPOT scenes and used to classify the images. Additionally, a stratified classification was carried out, by building separate Random Forests per landscape unit. Burrows were successfully classified in all landscape units. In the 'steppe on floodplain' areas, classification worked best: producer's and user's accuracy in those areas reached 88% and 100%, respectively. In the 'floodplain' areas with a more heterogeneous vegetation cover, classification worked least well; there, accuracies were 86 and 58% respectively. Stratified classification improved the results in all landscape units where comparison was possible (four), increasing kappa coefficients by 13, 10, 9 and 1%, respectively. In this study, an innovative stratification method using high- and medium resolution imagery was applied in order to map host distribution on a large spatial scale. The burrow maps we developed will help to detect changes in the distribution of great gerbil populations and, moreover, serve as a unique empirical

  12. Clues to Quasar Broad Line Region Geometry and Kinematics

    DEFF Research Database (Denmark)

    Vestergaard, Marianne; Wilkes, B. J.; Barthel, P. D.

    2000-01-01

    width to show significant inverse correlations with the fractional radio core-flux density, R, the radio axis inclination indicator. Highly inclined systems have broader line wings, consistent with a high-velocity field perpendicular to the radio axis. By contrast, the narrow line-core shows...... and with an accretion disk-wind emitting the broad lines. A spherical distribution of randomly orbiting broad-line clouds and a polar high-ionization outflow are ruled out....

  13. Host compatibility rather than vector–host-encounter rate determines the host range of avian Plasmodium parasites

    OpenAIRE

    Medeiros, Matthew C. I.; Hamer, Gabriel L.; Robert E. Ricklefs

    2013-01-01

    Blood-feeding arthropod vectors are responsible for transmitting many parasites between vertebrate hosts. While arthropod vectors often feed on limited subsets of potential host species, little is known about the extent to which this influences the distribution of vector-borne parasites in some systems. Here, we test the hypothesis that different vector species structure parasite–host relationships by restricting access of certain parasites to a subset of available hosts. Specifically, we inv...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-02-01

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

  15. 棉叶螨在冬春棉田田埂寄主植物上的分布%Distribution of Cotton Spider Mites on Host Plants on Cotton Field Ridge in Winter and Spring

    Institute of Scientific and Technical Information of China (English)

    裴艳芳; 黄秀琴; 王文凯; 郭永兵; 桂连友

    2012-01-01

    Distribution of cotton spider mites in winter and spring on host plants on 15 kinds of cotton fields ridge from 4 cotton planting districts in the middle reaches of Yangtze River, including Ruichang of Jiangxi Province, Li County of Hunan Province, Jingzhou District and Jiangbei Farm of Hubei Province, was surveyed by equidistant sampling method. Trie results showed that there were 64 host plants species belonging to 27 families in cotton fields, among which Veronica polita Fries, Cayratia japvnua Cagnep and Youngia japonica DC. Were dominant host plants species. Trie ratio of number of adults and nymphs, larvae and eggs of cotton spider mites on host was 72.1:20.5:7.4, and the number of adults and nymphs was larger than the others. Cotton spider mites on host plants in fields where previous crop was wheat and herbicide was applied the least as only 3.33% plants were fed by cotton spider mites. There was no significant effect on the number of cotton spider mites on host plants on the cotton fields ridge in winter and spring by transforming pond or rice fields into cotton fields.%采用等距取样方法对棉叶螨在长江中游棉区包括江西瑞昌市、湖南澧县、湖北荆州区、湖北江北农场4个棉区15种类型田的冬春棉田田埂寄主植物上的分布进行了调查.结果表明,棉叶螨的寄主植物共有27科64种,婆婆纳(Veronica polita Fries)、乌蔹莓(Cayratia japonica Gagnep)和黄鹌菜(Youngia japonica DC)为棉叶螨的优势寄主;寄主植物上棉叶螨的若成螨、幼螨和卵数量比例为72.1:20.5:7.4,以若成螨数量最多;而前茬作物为小麦且使用除草剂的田块田埂上寄主植物的棉叶螨的数量最少,有螨株率仅为3.33%.由鱼塘或稻田改造棉田均没有明显影响田埂上寄主植物的棉叶螨数量.

  16. Ghost imaging with broad distance

    Institute of Scientific and Technical Information of China (English)

    段德洋; 张路; 杜少将; 夏云杰

    2015-01-01

    We present a scheme that is able to achieve the ghost imaging with broad distance. The physical nature of our scheme is that the different wavelength beams are separated in free space by an optical media according to the slow light or dispersion principle. Meanwhile, the equality of the optical distance of the two light arms is not violated. The photon correlation is achieved by the rotating ground glass plate (RGGP) and spatial light modulator (SLM), respectively. Our work shows that a monochromic ghost image can be obtained in the case of RGGP. More importantly, the position (or distance) of the object can be ascertained by the color of the image. Thus, the imaging and ranging processes are combined as one process for the first time to the best of our knowledge. In the case of SLM, we can obtain a colored image regardless of where the object is.

  17. Effects of host plants on distribution, abundance, developmental time and life table parameters of Oligonychus afrasiaticus (McGregor (Acari: Tetranychidae

    Directory of Open Access Journals (Sweden)

    Sameh Ben Chaaban

    2012-01-01

    Full Text Available The biology and ecology of the date palm mite O. afrasiaticus have been studied through regular inspection in Tunisian oases and laboratory observations. Results indicate that the start date of fruit infestation varied between years and by date palm variety. Start dates ranged from the first week to the third week of July. The period spent by the mite on fruits varied from one variety to another; lasting 8 weeks on the Deglet Noor variety, 2 to 5 weeks on Alig, 2 to 4 weeks on Kentichi dates, and 2 to 4 weeks on Bessr fruits. The Deglet Noor variety was the most susceptible to O. afrasiaticus. Mite populations on the pinnae remained low from May through December. During autumn and spring, O. afrasiaticus was found on sorghum leaves in the orchard ground-cover. A life table study in the laboratory at 27°C on six host plants (fruits of date palms varieties Deglet Noor, Alig, Kentichi, Bessr, and Deglet Noor pinnae and sorghum leaves showed that the life cycle of O. afrasiaticus differed among host plants with average values ranging between 13 on Alig fruits and 10.9 days on sorghum leaves. Relatively high fecundity was found on sorghum leaves (2 eggs/female/day during 5.2 oviposition days, while low fecundity values occurred on Deglet Noor pinnae and Alig fruits with 0.7 eggs/female/day during 5.4 days. Average longevity of O. afrasiaticus females ranged from 13.4 to 7.5 days on Deglet Noor fruits and sorghum leaves, respectively. Intrinsic rate of increase (r m was highest on sorghum leaves (0.171 and Deglet Noor fruits (0.166, and lowest on Alig fruits (0.103. Greater knowledge of life history traits and seasonal abundance of this species is needed in order to design appropriate control strategies.

  18. Photoionisation modelling of the broad line region

    Science.gov (United States)

    King, Anthea

    2016-08-01

    Two of the most fundamental questions regarding the broad line region (BLR) are "what is its structure?" and "how is it moving?" Baldwin et al. (1995) showed that by summing over an ensemble of clouds at differing densities and distances from the ionising source we can easily and naturally produce a spectrum similar to what is observed for AGN. This approach is called the `locally optimally emitting clouds' (LOC) model. This approach can also explain the well-observed stratification of emission lines in the BLR (e.g. Clavel et al. 1991, Peterson et al. 1991, Kollatschny et al. 2001) and `breathing' of BLR with changes in the continuum luminosity (Netzer & Mor 1990, Peterson et al. 2014) and is therefore a generally accepted model of the BLR. However, LOC predictions require some assumptions to be made about the distribution of the clouds within the BLR. By comparing photoionization predictions, for a distribution of cloud properties, with observed spectra we can infer something about the structure of the BLR and distribution of clouds. I use existing reverberation mapping data to constrain the structure of the BLR by observing how individual line strengths and ratios of different lines change in high and low luminosity states. I will present my initial constraints and discuss the challenges associated with the method.

  19. Geographical distribution and host selection of Leptotrombidium rubellum in some parts of Yunnan province%云南省部分地区微红纤恙螨的分布及宿主选择

    Institute of Scientific and Technical Information of China (English)

    耿明璐; 郭宪国; 郭宾

    2013-01-01

    Objective To investigate the geographical distribution and host selection of Leptotrombidium rubellum among different small mammal hosts in some areas of Yunnan province,China.Methods Field survey was carried out in 23 counties of Yunnan province between 2001 and 2011.Small mammal hosts were captured with mouse cages and traps with baits.Chigger mites on the surface of two auricles were scraped off by a bistoury,and then preserved in 70% ethanol.Every specimen of the chigger mites on the slides was finally identified into species under a microscope.Some conventional statistical methods were adopted to calculate all the collected chigger mite species and the constituent ratios of L,.rubellum in different areas and on different hosts,with prevalence (P),mean intensity (MI) and mean abundance (MA) on different hosts calculated.Linear regression was used to analyze the relationship among P,MI and MA.Patch index (m*/m) was used to measure the spatial patterns of L.rubellum among different individuals of related small mammal hosts.Results A total of 108 480 chigger mites were collected from the body surface of all the captured small mammal hosts.All the collected chigger mites were identified as 3 subfamilies,24 genera and 234 species.Of the 234 species of chigger mites,654 individuals of L.rubellum were collected,only in 4 counties.The collected individuals of L.rubellum accounted for 0.603% of the total mites (108 480 individuals).96.637% of L.rubellum came from flatland areas and habitats while only 3.363% of the L.rubellum were from the mountainous regions.The orderings of the hosts appeared as Rodentia and Insectivora harbored 96.296% and 2.469% respectively,of the collected while Lagomorpha and other orders there was no L rubellum found.Of 67 species (in 34 genera and 12 families of 5 orders),Rattus tanezumi (in genus Rattus and family Muridae of Rodentia)harbored 96.788% of the collected L.rubellum with relatively low prevalence (P=3.776%) or mean

  20. Geographical distribution of host animals of plague in residential areas in Yunnan Province%2007-2012年云南省居民区鼠疫宿主动物调查及其地理分布

    Institute of Scientific and Technical Information of China (English)

    刘霖; 刘正祥; 杜春红; 洪梅; 吴爱国; 宋志忠; 高子厚

    2014-01-01

    Objective To investigate the geographical distribution of plague host animals in residential areas and the association between plague and its distribution pattern in Yunnan Province.Methods A systematic investigation on fauna and community ecology of rodents was carried out in residential areas of 17 counties(cities) of Yunnan Province,southwestern China with different longitude,latitude and elevation from May 2007 to November 2012.The characteristics of the spatial distribution of flea communities along environmental gradients were analyzed using community structure indexes.Results A total of 390 small mammals were trapped in seventeen counties (cities),and the mammals were classified into 11 species and 7 genus in 4 families.Among all small host mammals,Rattus tanezumi,Rattus nitidus and Rattus norvegicus were dominant species of host animals in residential areas,accounting for 33.85% (132/390),20.77% (81/390) and 16.92% (66/390),respectively.The horizontal distribution of rodents showed that Rattus tanezumi was the widest species in residential areas,which was found at the longitude 98°-105°,followed by Rattus norvegicus,Rattus yunnanensis and Mus musculus.The vertical and latitudinal distributions of rodents were similar in residential areas.Rattus tanezumi was also the widest distributed species,which was observed at the latitude 21°-< 28°N and at the altitude 500-< 3 500 m; the constituent of Rattus tanezumi showed similar trends of leaning peak curves,first gradually increasing and then decreasing with the increase of latitude and elevation; Rattus tanezumi gradually changed into Rattus nitidus and Apodemus chevrieri,et al.The richness spatial distribution patterns of host animals showed similar trends of leaning peak curves which gradually increased and then decreased with increasing of longitude and latitude; the highest richness was observed at the longitude 98°-< 101°E and at the latitude 23°-< 28°N.While,the richness spatial d

  1. Biodiversity inhibits parasites: Broad evidence for the dilution effect.

    Science.gov (United States)

    Civitello, David J; Cohen, Jeremy; Fatima, Hiba; Halstead, Neal T; Liriano, Josue; McMahon, Taegan A; Ortega, C Nicole; Sauer, Erin Louise; Sehgal, Tanya; Young, Suzanne; Rohr, Jason R

    2015-07-14

    Infectious diseases of humans, wildlife, and domesticated species are increasing worldwide, driving the need to understand the mechanisms that shape outbreaks. Simultaneously, human activities are drastically reducing biodiversity. These concurrent patterns have prompted repeated suggestions that biodiversity and disease are linked. For example, the dilution effect hypothesis posits that these patterns are causally related; diverse host communities inhibit the spread of parasites via several mechanisms, such as by regulating populations of susceptible hosts or interfering with parasite transmission. However, the generality of the dilution effect hypothesis remains controversial, especially for zoonotic diseases of humans. Here we provide broad evidence that host diversity inhibits parasite abundance using a meta-analysis of 202 effect sizes on 61 parasite species. The magnitude of these effects was independent of host density, study design, and type and specialization of parasites, indicating that dilution was robust across all ecological contexts examined. However, the magnitude of dilution was more closely related to the frequency, rather than density, of focal host species. Importantly, observational studies overwhelmingly documented dilution effects, and there was also significant evidence for dilution effects of zoonotic parasites of humans. Thus, dilution effects occur commonly in nature, and they may modulate human disease risk. A second analysis identified similar effects of diversity in plant-herbivore systems. Thus, although there can be exceptions, our results indicate that biodiversity generally decreases parasitism and herbivory. Consequently, anthropogenic declines in biodiversity could increase human and wildlife diseases and decrease crop and forest production.

  2. Ghost imaging with broad distance

    Science.gov (United States)

    Duan, De-Yang; Zhang, Lu; Du, Shao-Jiang; Xia, Yun-Jie

    2015-10-01

    We present a scheme that is able to achieve the ghost imaging with broad distance. The physical nature of our scheme is that the different wavelength beams are separated in free space by an optical media according to the slow light or dispersion principle. Meanwhile, the equality of the optical distance of the two light arms is not violated. The photon correlation is achieved by the rotating ground glass plate (RGGP) and spatial light modulator (SLM), respectively. Our work shows that a monochromic ghost image can be obtained in the case of RGGP. More importantly, the position (or distance) of the object can be ascertained by the color of the image. Thus, the imaging and ranging processes are combined as one process for the first time to the best of our knowledge. In the case of SLM, we can obtain a colored image regardless of where the object is. Project supported by the National Natural Science Foundation of China (Grant Nos. 61178012, 11204156, 11304179, and 11247240), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant Nos. 20133705110001 and 20123705120002), the Scientific Research Foundation for Outstanding Young Scientists of Shandong Province, China (Grant No. BS2013DX034), and the Natural Science Foundation of Shandong Province, China (Grant No. ZR2012FQ024).

  3. 78 FR 20119 - Broad Stakeholder Survey

    Science.gov (United States)

    2013-04-03

    ... SECURITY Broad Stakeholder Survey AGENCY: National Protection and Programs Directorate, DHS. ACTION: 30-day... soliciting comments concerning the Broad Stakeholder Survey. DHS previously published this ICR in the Federal... responders across the Nation. The Broad Stakeholder Survey is designed to gather stakeholder feedback on...

  4. 77 FR 50144 - Broad Stakeholder Survey

    Science.gov (United States)

    2012-08-20

    ... SECURITY Broad Stakeholder Survey AGENCY: National Protection and Programs Directorate, DHS. ACTION: 60-day... comments concerning the Broad Stakeholder Survey. DATES: Comments are encouraged and will be accepted until... across the Nation. The Broad Stakeholder Survey is designed to gather stakeholder feedback on...

  5. 76 FR 34087 - Broad Stakeholder Survey

    Science.gov (United States)

    2011-06-10

    ... SECURITY Broad Stakeholder Survey AGENCY: National Protection and Programs Directorate, DHS. ACTION: 60-day... comments concerning the Broad Stakeholder Survey. DATES: Comments are encouraged and will be accepted until.... The Broad Stakeholder Survey is designed to gather stakeholder feedback on the effectiveness of...

  6. A broad distribution of the alternative oxidase in microsporidian parasites.

    Directory of Open Access Journals (Sweden)

    Bryony A P Williams

    2010-02-01

    Full Text Available Microsporidia are a group of obligate intracellular parasitic eukaryotes that were considered to be amitochondriate until the recent discovery of highly reduced mitochondrial organelles called mitosomes. Analysis of the complete genome of Encephalitozoon cuniculi revealed a highly reduced set of proteins in the organelle, mostly related to the assembly of iron-sulphur clusters. Oxidative phosphorylation and the Krebs cycle proteins were absent, in keeping with the notion that the microsporidia and their mitosomes are anaerobic, as is the case for other mitosome bearing eukaryotes, such as Giardia. Here we provide evidence opening the possibility that mitosomes in a number of microsporidian lineages are not completely anaerobic. Specifically, we have identified and characterized a gene encoding the alternative oxidase (AOX, a typically mitochondrial terminal oxidase in eukaryotes, in the genomes of several distantly related microsporidian species, even though this gene is absent from the complete genome of E. cuniculi. In order to confirm that these genes encode functional proteins, AOX genes from both A. locustae and T. hominis were over-expressed in E. coli and AOX activity measured spectrophotometrically using ubiquinol-1 (UQ-1 as substrate. Both A. locustae and T. hominis AOX proteins reduced UQ-1 in a cyanide and antimycin-resistant manner that was sensitive to ascofuranone, a potent inhibitor of the trypanosomal AOX. The physiological role of AOX microsporidia may be to reoxidise reducing equivalents produced by glycolysis, in a manner comparable to that observed in trypanosomes.

  7. A broad distribution of the alternative oxidase in microsporidian parasites.

    OpenAIRE

    Williams, Bryony A P; Catherine Elliot; Lena Burri; Yasutoshi Kido; Kiyoshi Kita; Moore, Anthony L.; Patrick J Keeling

    2010-01-01

    Microsporidia are a group of obligate intracellular parasitic eukaryotes that were considered to be amitochondriate until the recent discovery of highly reduced mitochondrial organelles called mitosomes. Analysis of the complete genome of Encephalitozoon cuniculi revealed a highly reduced set of proteins in the organelle, mostly related to the assembly of iron-sulphur clusters. Oxidative phosphorylation and the Krebs cycle proteins were absent, in keeping with the notion that the microsporidi...

  8. A broad distribution of the alternative oxidase in microsporidian parasites

    OpenAIRE

    Williams, Bryony A P; Elliott, Catherine; Burri, Lena; Kido, Yasutoshi; Kita, Kiyoshi; Moore, Anthony L.; Patrick J Keeling

    2010-01-01

    Microsporidia are a group of obligate intracellular parasitic eukaryotes that were considered to be amitochondriate until the recent discovery of highly reduced mitochondrial organelles called mitosomes. Analysis of the complete genome of Encephalitozoon cuniculi revealed a highly reduced set of proteins in the organelle, mostly related to the assembly of iron-sulphur clusters. Oxidative phosphorylation and the Krebs cycle proteins were absent, in keeping with the notion that the microsporidi...

  9. Packaging and Performance of 980nm Broad Area Semiconductor Lasers

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    High power broad area semiconductor lasers have found increasing applications in pumping of solid state laser systems and fiber amplifiers, frequency doubling, medical systems and material processing.Packaging including the assembly design, process and thermal management, has a significant impact on the optical performance and reliability of a high power broad area laser. In this paper, we introduce the package structures and assembling process of 980nm broad area lasers and report the performances including output power, thermal behavior and far fields.We will report two types of high power broad area laser assemblies.One is a microchannel liquid cooled assembly and the other is a conduction cooled CT-mount assembly. Optical powers of 15W and 10W were achieved from a 980nm broad area laser with a 120 μ m stripe width in a microchannel liquid cooled assembly and conduction cooled CT-mount assembly, respectively.Furthermore,a high power of 6.5W out of fiber was demonstrated from a pigtailed, fully packaged butterfly-type module without TEC (Thermoelectric cooler).The measurement results showed that thermal management is the key in not only improving output power, but also significantly improving beam divergence and far field distribution.The results also showed that the die attach solder can significant impact the reliability of high power broad area lasers and that indium solder is not suitable for high power laser applications due to electromigration at high current densities and high temperatures.

  10. Broad Band Properties of the BAT Selected AGN

    Science.gov (United States)

    Mushotzky, Richard; Winter, Lisa; Tueller, Jack

    2008-01-01

    I will present the x-ray spectral properties of approx.150 BAT selected ACN focusing on the issues of spectral complexity, x-ray absorption and its distribution and that contribution of sources to the x-ray background. If time permits we will also present the nature of the host galaxies of the ACN and their relationship to merger candidates.

  11. The Role of Within-Host Competition for Coexistence in Multiparasitoid-Host Systems.

    Science.gov (United States)

    van Velzen, Ellen; Pérez-Vila, Saleta; Etienne, Rampal S

    2016-01-01

    Multiparasitism (females of multiple species parasitizing the same host) is a ubiquitous phenomenon in parasitoids, yet the role of within-host competition has been mostly ignored in multiparasitoid-host models. Here we study the effect of varying the degree of competition at different life stages: competition over oviposition sites (between-adult competition) and larval competition over resources within the host (within-host competition). We adapt a Nicholson-Bailey model to allow for varying levels of between-adult competition (varying the overlap in species distributions) and within-host competition (varying the number of offspring that can successfully emerge from a host). Surprisingly, while stronger between-adult competition reduces coexistence, stronger within-host competition promotes it. Asymmetric between-adult competition (a fecundity difference between the two species) reduces coexistence when compared to symmetric competition; this can be counteracted by asymmetric within-host competition (within-host competitive advantage of the lower-fecundity species), but only when within-host competition is strong and the correlation between the parasitoids' distributions is intermediate. We discuss our results in the context of the interaction between two parasitoid species, Nasonia vitripennis and Nasonia giraulti, which have strongly correlated distributions and high levels of multiparasitism in the field. We conclude that either low or asymmetric within-host competition is unlikely to explain their coexistence.

  12. The Role of Within-Host Competition for Coexistence in Multiparasitoid-Host Systems.

    Science.gov (United States)

    van Velzen, Ellen; Pérez-Vila, Saleta; Etienne, Rampal S

    2016-01-01

    Multiparasitism (females of multiple species parasitizing the same host) is a ubiquitous phenomenon in parasitoids, yet the role of within-host competition has been mostly ignored in multiparasitoid-host models. Here we study the effect of varying the degree of competition at different life stages: competition over oviposition sites (between-adult competition) and larval competition over resources within the host (within-host competition). We adapt a Nicholson-Bailey model to allow for varying levels of between-adult competition (varying the overlap in species distributions) and within-host competition (varying the number of offspring that can successfully emerge from a host). Surprisingly, while stronger between-adult competition reduces coexistence, stronger within-host competition promotes it. Asymmetric between-adult competition (a fecundity difference between the two species) reduces coexistence when compared to symmetric competition; this can be counteracted by asymmetric within-host competition (within-host competitive advantage of the lower-fecundity species), but only when within-host competition is strong and the correlation between the parasitoids' distributions is intermediate. We discuss our results in the context of the interaction between two parasitoid species, Nasonia vitripennis and Nasonia giraulti, which have strongly correlated distributions and high levels of multiparasitism in the field. We conclude that either low or asymmetric within-host competition is unlikely to explain their coexistence. PMID:27277402

  13. Novel lanthanide doped micro- and mesoporous solids. Characterization of ion-host-interactions, species distribution and luminescence properties using time-resolved luminescence spectroscopy; Neuartige Lanthanoid-dotierte mikro- und mesoporoese Feststoffe. Charakterisierung von Ion-Wirt-Wechselwirkungen, Speziesverteilung und Lumineszenzeigenschaften mittels zeitaufgeloester Lumineszenzspektroskopie

    Energy Technology Data Exchange (ETDEWEB)

    Gessner, Andre

    2010-12-15

    In this work lanthanide-doped microporous zeolites, microporous-mesoporous hybrid materials and mesoporous silicates were investigated regarding their luminescence properties and the ion-host-interactions using time-resolved luminescence spectroscopy. Thereby, time-resolved emission spectra (TRES) provide information in the wavelength and time domain. For the analysis of the TRES a broad set of analytic methods was applied and thus a corresponding ''toolbox'' developed. Fitting of the luminescence decays was performed with a discrete number of exponentials and supported by luminescence decay times distributions. Time-resolved area normalized emission spectra (TRANES), an advancement of TRES, could be used for the determination of the number of emissive lanthanide species in porous materials for the first time. Calculation of the decay-associated spectra (DAS) allowed the correlation of spectral information with luminescence decay times and thus delivered the luminescence spectra of the different europium species. For europium(III) we could use in addition the time-dependent asymmetry ratio and spectral evolution of the {sup 5}D{sub 0}-{sup 7}F{sub 0}-transition with time to obtain further information about the distribution of the lanthanide ions in the host material. Luminescence decay times and spectra allowed conclusions on the number of OH-oscillators in and the symmetry of the first coordination sphere. For the microporous and microporous-mesoporous materials were found different lanthanide species, which were characterized by the above mentioned methods. These lanthanide species can be found on different positions in the host material. One position is located deep in the pore system. Here, lanthanide ions are hardly accessible for water and mainly coordinated by framework oxygens. This results in long luminescence decay times and distorted coordination spheres. The second position can be found near or on the outer surface or in the

  14. Ectoparasites of the whitespotted rabbitfish, Siganus sutor (Valenciennes, 1835) off the Kenyan Coast: distribution within the host population and site selection on the gills.

    Science.gov (United States)

    Geets, A; Coene, H; Ollevier, F

    1997-07-01

    Different populations of the whitespotted rabbitfish, Siganus sutor, were examined for ectoparasites: adults from the Mombasa area (sampled in December 1990) and different age classes (adult, subadult and juveniles) from Gazi Bay (sampled in December 1992 and August 1993). The most common gill parasites were: the monogeneans Pseudohaliotrema sp., Tetrancistrum sigani and Microcotyle mouwoi, the copepods Hatschekia sp., Pseudolepeophtheirus sp. and juvenile Caligidae, and prazina larvae of the isopod Gnathia sp. Adult siganids had a higher parasite load than subadults. Juvenile rabbitfish did not harbour any gill parasites. Temporal differences in the parasite load of subadult rabbitfish were observed for M. mouwoi (highest in the December samples) and for juvenile Caligidae (highest in August). The microhabitat of the 5 most common gill parasites was species specific. Most parasite species showed distinct site preferences with respect to both gill arches and gill sectors, within the gill arches. Niche breadth of the different gill parasite species was independent of the abundance of any of the other species present. However, niche breadths of M. mouwoi, Tetrancistrum sp. and Hatschekia sp. increased with their own abundance. This suggests that interspecific competition for space is low and that intraspecific factors could play an important role in the microhabitat choice of these gill parasites. The hypothesis that niche restriction leads to higher intraspecific contact and an enhancement of chances to mate was tested on 2 monogenean species, Pseudohaliotrema sp. and Tetrancistrum sigani. Their highly aggregated distribution over the gill filaments, leading to increased intraspecific contact, is consistent with the hypothesis.

  15. Mimetic host shifts in an endangered social parasite of ants

    Science.gov (United States)

    Thomas, Jeremy A.; Elmes, Graham W.; Sielezniew, Marcin; Stankiewicz-Fiedurek, Anna; Simcox, David J.; Settele, Josef; Schönrogge, Karsten

    2013-01-01

    An emerging problem in conservation is whether listed morpho-species with broad distributions, yet specialized lifestyles, consist of more than one cryptic species or functionally distinct forms that have different ecological requirements. We describe extreme regional divergence within an iconic endangered butterfly, whose socially parasitic young stages use non-visual, non-tactile cues to infiltrate and supplant the brood in ant societies. Although indistinguishable morphologically or when using current mitochondrial and nuclear sequence-, or microsatellite data, Maculinea rebeli from Spain and southeast Poland exploit different Myrmica ant species and experience 100 per cent mortality with each other's hosts. This reflects major differences in the hydrocarbons synthesized from each region by the larvae, which so closely mimic the recognition profiles of their respective hosts that nurse ants afford each parasite a social status above that of their own kin larvae. The two host ants occupy separate niches within grassland; thus, conservation management must differ in each region. Similar cryptic differentiation may be common, yet equally hard to detect, among the approximately 10 000 unstudied morpho-species of social parasite that are estimated to exist, many of which are Red Data Book listed. PMID:23193127

  16. A veritable menagerie of heritable bacteria from ants, butterflies, and beyond: broad molecular surveys and a systematic review.

    Directory of Open Access Journals (Sweden)

    Jacob A Russell

    Full Text Available Maternally transmitted bacteria have been important players in the evolution of insects and other arthropods, affecting their nutrition, defense, development, and reproduction. Wolbachia are the best studied among these and typically the most prevalent. While several other bacteria have independently evolved a heritable lifestyle, less is known about their host ranges. Moreover, most groups of insects have not had their heritable microflora systematically surveyed across a broad range of their taxonomic diversity. To help remedy these shortcomings we used diagnostic PCR to screen for five groups of heritable symbionts-Arsenophonus spp., Cardinium hertigii, Hamiltonella defensa, Spiroplasma spp., and Wolbachia spp.-across the ants and lepidopterans (focusing, in the latter case, on two butterfly families-the Lycaenidae and Nymphalidae. We did not detect Cardinium or Hamiltonella in any host. Wolbachia were the most widespread, while Spiroplasma (ants and lepidopterans and Arsenophonus (ants only were present at low levels. Co-infections with different Wolbachia strains appeared especially common in ants and less so in lepidopterans. While no additional facultative heritable symbionts were found among ants using universal bacterial primers, microbes related to heritable enteric bacteria were detected in several hosts. In summary, our findings show that Wolbachia are the dominant heritable symbionts of ants and at least some lepidopterans. However, a systematic review of symbiont frequencies across host taxa revealed that this is not always the case across other arthropods. Furthermore, comparisons of symbiont frequencies revealed that the prevalence of Wolbachia and other heritable symbionts varies substantially across lower-level arthropod taxa. We discuss the correlates, potential causes, and implications of these patterns, providing hypotheses on host attributes that may shape the distributions of these influential bacteria.

  17. A veritable menagerie of heritable bacteria from ants, butterflies, and beyond: broad molecular surveys and a systematic review.

    Science.gov (United States)

    Russell, Jacob A; Funaro, Colin F; Giraldo, Ysabel M; Goldman-Huertas, Benjamin; Suh, David; Kronauer, Daniel J C; Moreau, Corrie S; Pierce, Naomi E

    2012-01-01

    Maternally transmitted bacteria have been important players in the evolution of insects and other arthropods, affecting their nutrition, defense, development, and reproduction. Wolbachia are the best studied among these and typically the most prevalent. While several other bacteria have independently evolved a heritable lifestyle, less is known about their host ranges. Moreover, most groups of insects have not had their heritable microflora systematically surveyed across a broad range of their taxonomic diversity. To help remedy these shortcomings we used diagnostic PCR to screen for five groups of heritable symbionts-Arsenophonus spp., Cardinium hertigii, Hamiltonella defensa, Spiroplasma spp., and Wolbachia spp.-across the ants and lepidopterans (focusing, in the latter case, on two butterfly families-the Lycaenidae and Nymphalidae). We did not detect Cardinium or Hamiltonella in any host. Wolbachia were the most widespread, while Spiroplasma (ants and lepidopterans) and Arsenophonus (ants only) were present at low levels. Co-infections with different Wolbachia strains appeared especially common in ants and less so in lepidopterans. While no additional facultative heritable symbionts were found among ants using universal bacterial primers, microbes related to heritable enteric bacteria were detected in several hosts. In summary, our findings show that Wolbachia are the dominant heritable symbionts of ants and at least some lepidopterans. However, a systematic review of symbiont frequencies across host taxa revealed that this is not always the case across other arthropods. Furthermore, comparisons of symbiont frequencies revealed that the prevalence of Wolbachia and other heritable symbionts varies substantially across lower-level arthropod taxa. We discuss the correlates, potential causes, and implications of these patterns, providing hypotheses on host attributes that may shape the distributions of these influential bacteria.

  18. Population dynamics of a Salmonella lytic phage and its host: implications of the host bacterial growth rate in modelling.

    Science.gov (United States)

    Santos, Sílvio B; Carvalho, Carla; Azeredo, Joana; Ferreira, Eugénio C

    2014-01-01

    The prevalence and impact of bacteriophages in the ecology of bacterial communities coupled with their ability to control pathogens turn essential to understand and predict the dynamics between phage and bacteria populations. To achieve this knowledge it is essential to develop mathematical models able to explain and simulate the population dynamics of phage and bacteria. We have developed an unstructured mathematical model using delay-differential equations to predict the interactions between a broad-host-range Salmonella phage and its pathogenic host. The model takes into consideration the main biological parameters that rule phage-bacteria interactions likewise the adsorption rate, latent period, burst size, bacterial growth rate, and substrate uptake rate, among others. The experimental validation of the model was performed with data from phage-interaction studies in a 5 L bioreactor. The key and innovative aspect of the model was the introduction of variations in the latent period and adsorption rate values that are considered as constants in previous developed models. By modelling the latent period as a normal distribution of values and the adsorption rate as a function of the bacterial growth rate it was possible to accurately predict the behaviour of the phage-bacteria population. The model was shown to predict simulated data with a good agreement with the experimental observations and explains how a lytic phage and its host bacteria are able to coexist. PMID:25051248

  19. Population dynamics of a Salmonella lytic phage and its host: implications of the host bacterial growth rate in modelling.

    Directory of Open Access Journals (Sweden)

    Sílvio B Santos

    Full Text Available The prevalence and impact of bacteriophages in the ecology of bacterial communities coupled with their ability to control pathogens turn essential to understand and predict the dynamics between phage and bacteria populations. To achieve this knowledge it is essential to develop mathematical models able to explain and simulate the population dynamics of phage and bacteria. We have developed an unstructured mathematical model using delay-differential equations to predict the interactions between a broad-host-range Salmonella phage and its pathogenic host. The model takes into consideration the main biological parameters that rule phage-bacteria interactions likewise the adsorption rate, latent period, burst size, bacterial growth rate, and substrate uptake rate, among others. The experimental validation of the model was performed with data from phage-interaction studies in a 5 L bioreactor. The key and innovative aspect of the model was the introduction of variations in the latent period and adsorption rate values that are considered as constants in previous developed models. By modelling the latent period as a normal distribution of values and the adsorption rate as a function of the bacterial growth rate it was possible to accurately predict the behaviour of the phage-bacteria population. The model was shown to predict simulated data with a good agreement with the experimental observations and explains how a lytic phage and its host bacteria are able to coexist.

  20. Neutralization of low energy broad ion beam

    International Nuclear Information System (INIS)

    The paper is devoted to experimental and theoretical investigation of a low energy broad ion beam space charge and current compensation and ion-beam plasma (IBP), which would be created in transport space of the beam. The beam had cylindrical symmetry. The continuous uniform and hole tube like ion beams are used in the experiments. Different channels of electron appearing have been investigated for cases of neutralization due to secondary γ-electrons from the target and by electrons from glow cathode-neutralizer with metal or dielectric target. Results of neutralizing electrons energy distributions function measurements are presented as well as dependences of electron temperature and self-consisted plasma potential vs. beam parameters, ambient gas pressure, neutralizer parameters. Role of the thermoelectrons and dependence of IBP parameters on neutralizer area, location and potential are discussed. Significant role in neutralization of spatial collisional processes has been revealed even in neutralization by thermocathode. On the base of the experimental results self-consistent theoretical model have been developed, which describes the behavior of intense ion beam passing through the neutral gas at low pressure within conductive walls. The collisionless approach is used which means absence of collisional relaxation of the beam. This theory is used to derive the plasma potential and electron temperature within the beam

  1. Rates and properties of type Ia supernovae as a function of mass and star-formation in their host galaxies

    CERN Document Server

    Sullivan, M; Pritchet, C J; Hodsman, A; Neill, J D; Howell, D A; Carlberg, R G; Astier, Pierre; Aubourg, E; Balam, D; Basa, S; Conley, A; Fabbro, S; Fouchez, D; Guy, J; Hook, I; Pain, R; Palanque-Delabrouille, Nathalie; Perrett, K; Regnault, N; Rich, J; Taillet, R; Baumont, S; Bronder, J; Ellis, Richard S; Filiol, M; Lusset, V; Perlmutter, S; Ripoche, P; Tao, C

    2006-01-01

    (ABRIDGED) We show that Type Ia supernovae (SNe Ia) are formed within both very young and old stellar populations, with observed rates that depend on the stellar mass and mean star-formation rates (SFRs) of their host galaxies. Models where the SN Ia rate depends solely on host galaxy stellar mass are ruled out with 99% confidence. Our analysis is based on 100 spectroscopically-confirmed SNe Ia, plus 24 photometrically-classified events, all from the Supernova Legacy Survey (SNLS) and distributed over 0.2host galaxies by fitting their broad-band spectral energy distributions with the galaxy spectral synthesis code, PEGASE.2. We show that the SN Ia rate per unit mass is proportional to the specific SFR of the parent galaxies -- more vigorously star-forming galaxies host more SNe Ia per unit stellar mass, broadly equivalent to the trend of increasing SN Ia rate in later-type galaxies seen in the local universe. Followi...

  2. Trusted Hosts in Host Identity Protocol (HIP)

    OpenAIRE

    K.C., Amir

    2012-01-01

    The goal of the project was to study the possibilities to establish trusted hosts in Host Identity Protocol (HIP) and implement certificate handling in HIP packets. The time complexity and performance while using certificates in HIP packets was also measured. The research project was carried out at Arcada University of Applied Sciences in collaboration with Helsinki University. The project aimed to implement standard x.509 certification of the public key used as HI (Host Identity) to deri...

  3. Porous Silicon—A Versatile Host Material

    Directory of Open Access Journals (Sweden)

    Klemens Rumpf

    2010-02-01

    Full Text Available This work reviews the use of porous silicon (PS as a nanomaterial which is extensively investigated and utilized for various applications, e.g., in the fields of optics, sensor technology and biomedicine. Furthermore the combination of PS with one or more materials which are also nanostructured due to their deposition within the porous matrix is discussed. Such nanocompounds offer a broad avenue of new and interesting properties depending on the kind of involved materials as well as on their morphology. The filling of the pores performed by electroless or electrochemical deposition is described, whereas different morphologies, reaching from micro- to macro pores are utilized as host material which can be self-organized or fabricated by prestructuring. For metal-deposition within the porous structures, both ferromagnetic and non-magnetic metals are used. Emphasis will be put on self-arranged mesoporous silicon, offering a quasi-regular pore arrangement, employed as template for filling with ferromagnetic metals. By varying the deposition parameters the precipitation of the metal structures within the pores can be tuned in geometry and spatial distribution leading to samples with desired magnetic properties. The correlation between morphology and magnetic behaviour of such semiconducting/magnetic systems will be determined. Porous silicon and its combination with a variety of filling materials leads to nanocomposites with specific physical properties caused by the nanometric size and give rise to a multiplicity of potential applications in spintronics, magnetic and magneto-optic devices, nutritional food additives as well as drug delivery.

  4. Broad Prize: Do the Successes Spread?

    Science.gov (United States)

    Samuels, Christina A.

    2011-01-01

    When the Broad Prize for Urban Education was created in 2002, billionaire philanthropist Eli Broad said he hoped the awards, in addition to rewarding high-performing school districts, would foster healthy competition; boost the prestige of urban education, long viewed as dysfunctional; and showcase best practices. Over the 10 years the prize has…

  5. Migration, Prospecting, Dispersal? What Host Movement Matters for Infectious Agent Circulation?

    Science.gov (United States)

    Boulinier, Thierry; Kada, Sarah; Ponchon, Aurore; Dupraz, Marlène; Dietrich, Muriel; Gamble, Amandine; Bourret, Vincent; Duriez, Olivier; Bazire, Romain; Tornos, Jérémy; Tveraa, Torkild; Chambert, Thierry; Garnier, Romain; McCoy, Karen D

    2016-08-01

    Spatial disease ecology is emerging as a new field that requires the integration of complementary approaches to address how the distribution and movements of hosts and parasites may condition the dynamics of their interactions. In this context, migration, the seasonal movement of animals to different zones of their distribution, is assumed to play a key role in the broad scale circulation of parasites and pathogens. Nevertheless, migration is not the only type of host movement that can influence the spatial ecology, evolution, and epidemiology of infectious diseases. Dispersal, the movement of individuals between the location where they were born or bred to a location where they breed, has attracted attention as another important type of movement for the spatial dynamics of infectious diseases. Host dispersal has notably been identified as a key factor for the evolution of host-parasite interactions as it implies gene flow among local host populations and thus can alter patterns of coevolution with infectious agents across spatial scales. However, not all movements between host populations lead to dispersal per se. One type of host movement that has been neglected, but that may also play a role in parasite spread is prospecting, i.e., movements targeted at selecting and securing new habitat for future breeding. Prospecting movements, which have been studied in detail in certain social species, could result in the dispersal of infectious agents among different host populations without necessarily involving host dispersal. In this article, we outline how these various types of host movements might influence the circulation of infectious disease agents and discuss methodological approaches that could be used to assess their importance. We specifically focus on examples from work on colonial seabirds, ticks, and tick-borne infectious agents. These are convenient biological models because they are strongly spatially structured and involve relatively simple communities

  6. Migration, Prospecting, Dispersal? What Host Movement Matters for Infectious Agent Circulation?

    Science.gov (United States)

    Boulinier, Thierry; Kada, Sarah; Ponchon, Aurore; Dupraz, Marlène; Dietrich, Muriel; Gamble, Amandine; Bourret, Vincent; Duriez, Olivier; Bazire, Romain; Tornos, Jérémy; Tveraa, Torkild; Chambert, Thierry; Garnier, Romain; McCoy, Karen D

    2016-08-01

    Spatial disease ecology is emerging as a new field that requires the integration of complementary approaches to address how the distribution and movements of hosts and parasites may condition the dynamics of their interactions. In this context, migration, the seasonal movement of animals to different zones of their distribution, is assumed to play a key role in the broad scale circulation of parasites and pathogens. Nevertheless, migration is not the only type of host movement that can influence the spatial ecology, evolution, and epidemiology of infectious diseases. Dispersal, the movement of individuals between the location where they were born or bred to a location where they breed, has attracted attention as another important type of movement for the spatial dynamics of infectious diseases. Host dispersal has notably been identified as a key factor for the evolution of host-parasite interactions as it implies gene flow among local host populations and thus can alter patterns of coevolution with infectious agents across spatial scales. However, not all movements between host populations lead to dispersal per se. One type of host movement that has been neglected, but that may also play a role in parasite spread is prospecting, i.e., movements targeted at selecting and securing new habitat for future breeding. Prospecting movements, which have been studied in detail in certain social species, could result in the dispersal of infectious agents among different host populations without necessarily involving host dispersal. In this article, we outline how these various types of host movements might influence the circulation of infectious disease agents and discuss methodological approaches that could be used to assess their importance. We specifically focus on examples from work on colonial seabirds, ticks, and tick-borne infectious agents. These are convenient biological models because they are strongly spatially structured and involve relatively simple communities

  7. New host plant and distribution records for weevils of the genus Hydnorobius (Coleoptera: Belidae Nuevos registros de planta hospedadora y de distribución para gorgojos del género Hydnorobius (Coleoptera: Belidae

    Directory of Open Access Journals (Sweden)

    María S. Ferrer

    2010-12-01

    Full Text Available The association of Hydnorobius hydnorae (Pascoe (Belidae: Oxycoryninae with both species of the genus Prosopanche de Bary (Hydnoraceae, Prosopanche americana (R. Br. Baillon and Prosopanche bonacinai Spegazzini, is reported, providing the first record of its occurrence on the latter. A new distribution record, from Southern Mendoza, is given for the plant P. bonacinai and for the two weevil species associated with it: Hydnorobius hydnorae and Hydnorobius parvulus (Bruch. Such cooccurrence of two species of Hydnorobius Kuschel on the same host plant is also recorded for the first time.Se reporta la asociación de Hydnorobius hydnorae (Pascoe (Belidae: Oxycoryninae con ambas especies del género Prosopanche de Bary (Hydnoraceae: Prosopanche americana (R. Br. Baillon y Prosopanche bonacinai Spegazzini, y se cita por primera vez su ocurrencia sobre estaúltima. Se brinda un nuevo registro de distribución en el sur de Mendoza, para la planta P. bonacinai y para las dos especies de gorgojos asociadas con ella: Hydnorobius hydnorae e Hydnorobius parvulus (Bruch. Tal co-ocurrencia de dos especies de Hydnorobius Kuschel, sobre la misma planta hospedadora, también es información nueva.

  8. Tick-Host Specificity

    OpenAIRE

    Hoogstraal, H.; Aeschlimann, André

    2010-01-01

    A review the various patterns of tick-host relationships are discussed in detail in order to answer the following questions : 1. How, when and where did host specificity of each parasite group evolve ? 2. How strict is specificity in each case ? 3. Why and under what circumstances does specificity break down ? The authors present several definitions which characterize the various degrees of parasitic specificity existing today between ticks and their hosts. Tick-host relationships are ...

  9. The coevolutionary implications of host tolerance.

    Science.gov (United States)

    Best, Alex; White, Andy; Boots, Mike

    2014-05-01

    Host tolerance to infectious disease, whereby hosts do not directly "fight" parasites but instead ameliorate the damage caused, is an important defense mechanism in both plants and animals. Because tolerance to parasite virulence may lead to higher prevalence of disease in a population, evolutionary theory tells us that while the spread of resistance genes will result in negative frequency dependence and the potential for diversification, the evolution of tolerance is instead likely to result in fixation. However, our understanding of the broader implications of tolerance is limited by a lack of fully coevolutionary theory. Here we examine the coevolution of tolerance across a comprehensive range of classic coevolutionary host-parasite frameworks, including equivalents of gene-for-gene and matching allele and evolutionary invasion models. Our models show that the coevolution of host tolerance and parasite virulence does not lead to the generation and maintenance of diversity through either static polymorphisms or through "Red-queen" cycles. Coevolution of tolerance may however lead to multiple stable states leading to sudden shifts in parasite impacts on host health. More broadly, we emphasize that tolerance may change host-parasite interactions from antagonistic to a form of "apparent commensalism," but may also lead to the evolution of parasites that are highly virulent in nontolerant hosts.

  10. Measuring Prevention More Broadly, An Empirical...

    Data.gov (United States)

    U.S. Department of Health & Human Services — Measuring Prevention More Broadly, An Empirical Assessment of CHIPRA Core Measures Differences in CHIP design and structure, across states and over time, may limit...

  11. Host records for Ornithonyssus sylviarum (Mesostigmata: Macronyssidae) from birds of North America (Canada, United States, and Mexico).

    Science.gov (United States)

    Knee, Wayne; Proctor, Heather

    2007-07-01

    The northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago, 1877) (Mesostigmata: Macronyssidae) is a broadly distributed blood-feeding parasite that has been collected from many birds of temperate regions. Previously, the most complete host list was published in 1938, and it included 15 North American (Canada, United States, and Mexico) host species. In the process of a general survey of bird-associated mites in Alberta, Canada, we recovered many O. sylviarum specimens. Herein, we update the previous host list with these observations and records published since 1938. We collected mites by washing the bodies of salvaged birds and examining the filtrate. Northern fowl mites were collected from 26 host species, with 16 of these species being the first host records for North America. Including results from the current study, O. sylviarum has been reported from 72 species of North American birds from 26 families. This updated host list will be useful to anyone interested in the role of O. sylviarum in transmission of avian disease. PMID:17695029

  12. 多波段相关光子光谱分布与时间相关性测量实验研究%Research on the Distribution of Broad-Band Correlated Photon Spectra and the Measurement of Time-Correlation

    Institute of Scientific and Technical Information of China (English)

    高冬阳; 李健军; 夏茂鹏; 郑小兵

    2016-01-01

    parametric down-conversion, non-collinear angle formula of correlated photon in the crystal is derived.The distribution of the photon spectrum is simulated. Meanwhile,the phase-matching angle of the crystal is optimized.The photon generated by the spontaneous parameters down-conversion has a broad spectral distribution and the correlated photon wavelength is corresponding to its emission angle.Based on the result of the simulation,the experimental measurement system of the spectral distribution and time-correlation of the cor-related photon is established.The spectral distribution,the time-correlation and the polarization properties of the four pair pho-ton were measured by using this system.The experimental results show that,(1)the spectral distribution of the measurements is 633~808 nm,where the maximum spectral distribution measurement bias is 1.51 mm.The experiment result is highly con-sistent with theoretical ones;(2)the correlation time of four pairs correlated photon is measured,during which “three coinci-dence-peaks”is observed and the minimum correlation time was 0.32 ns;(3)single photon count rate along with coincidence count rate of correlated photon vary with the polarization direction of the pump as sine function.The experimental result is shown that the correlated photon pairs are ranging from the visible to near infrared band distribution,and that the spectrum has time-correlation and polarization characteristic.The research result is firstly reported at home and abroad,and the results are promising for the application of the photoelectric detector in the multi-band radiometric calibration.

  13. Distribution and polymorphisms of host killing genes in the plasmids metagenome of Escherichia coli%大肠杆菌质粒解离后致死基因分布及多态性分析

    Institute of Scientific and Technical Information of China (English)

    高国辉; 齐云玲; 孙倩; 宋智健; 宋玉龙; 李劲松; 王慧利; 包其郁; 丁力

    2011-01-01

    Objective To investigate the genotypes of host killing genes and their single nucleotide polymorphisms (SNPs). Methods Three hundred and twenty strains of Escherichia coli that collected from the First Affiliated Hospital of Wenzhou Medical College were analyzed. The first sample ( E1 ) contains 160 strains isolated during the years from 2002 to 2003. The second sample (E2) contains 160 strains covering the years from 2008 to 2009. The plasmids of Escherichia coli were extracted by alkaline lysis method. Solexa/Illumina sequencing technology was used to sequence plasmids metagenome. Solexa Genome Analysis System and Soap programs were used to analyze gene distribution, SNPs and lineage-specific mutations. Results 11 077 768 reads were generated and 0. 045% of them can map to the reference sequences from El sample. Whereas 9 377 792 reads were generated and 0. 053% of which mapped to the reference from E2 sample. There are nine host killing genes identified in the two samples, of which hok gene is the most prevalent. A total of 29 SNP sites dispersed in five genes of the two samples. Approximately 33% of them were non-synonymous mutations. One position of A and G is the most prevalent polymorphism. Conclusion The known nine genotypes of host killing genes were all identified in plasmids of Escherichia coli in Wenzhou. hok gene showed the highest frequency. There were SNPs in five genotypes.%目的 通过对来自不同年份大肠杆菌质粒DNA序列进行高通最测序,从质粒基因组水平分析大肠杆菌质粒DNA所携带的解离后致死基因的种类、数量以及多态性.方法 收集4年临床分离非重复的320株大肠杆菌.菌株分为两个部分,碱裂解法提取全部质粒DNA,Solexa测序获得大规模的短序列.采用比较基因组学方法分析两个样本所含的解离后致死基因类型及丰度的差异,研究解离后致死基因存在的核苷酸多态位点.结果 测序法获得两批数据,E1短序列总数为11 077 768

  14. Are Some Milky Way Globular Clusters Hosted by Undiscovered Galaxies?

    CERN Document Server

    Zaritsky, Dennis; Sand, David J

    2016-01-01

    The confirmation of a globular cluster (GC) in the recently discovered ultrafaint galaxy Eridanus II (Eri II) motivated us to examine the question posed in the title. After estimating the halo mass of Eri II using a published stellar mass - halo mass relation, the one GC in this galaxy supports extending the relationship between the number of GCs hosted by a galaxy and the galaxy's total mass about two orders of magnitude in stellar mass below the previous limit. For this empirically determined specific frequency of between 0.06 and 0.39 globular clusters per 10$^9$ $M_\\odot$ of total mass, the surviving Milky Way (MW) subhalos with masses smaller than $10^{10} M_\\odot$ could host as many as 5 to 31 GCs, broadly consistent with the actual population of outer halo MW GCs, although matching the radial distribution in detail remains a challenge. Using a subhalo mass function from published high resolution numerical simulations and a Poissonian model for populating those halos with the aforementioned empirically ...

  15. BROAD PHONEME CLASSIFICATION USING SIGNAL BASED FEATURES

    Directory of Open Access Journals (Sweden)

    Deekshitha G

    2014-12-01

    Full Text Available Speech is the most efficient and popular means of human communication Speech is produced as a sequence of phonemes. Phoneme recognition is the first step performed by automatic speech recognition system. The state-of-the-art recognizers use mel-frequency cepstral coefficients (MFCC features derived through short time analysis, for which the recognition accuracy is limited. Instead of this, here broad phoneme classification is achieved using features derived directly from the speech at the signal level itself. Broad phoneme classes include vowels, nasals, fricatives, stops, approximants and silence. The features identified useful for broad phoneme classification are voiced/unvoiced decision, zero crossing rate (ZCR, short time energy, most dominant frequency, energy in most dominant frequency, spectral flatness measure and first three formants. Features derived from short time frames of training speech are used to train a multilayer feedforward neural network based classifier with manually marked class label as output and classification accuracy is then tested. Later this broad phoneme classifier is used for broad syllable structure prediction which is useful for applications such as automatic speech recognition and automatic language identification.

  16. Microbial modification of host long-distance dispersal capacity

    Directory of Open Access Journals (Sweden)

    Hutchings Linda

    2009-06-01

    Full Text Available Abstract Background Dispersal plays a key role in shaping biological and ecological processes such as the distribution of spatially-structured populations or the pace and scale of invasion. Here we have studied the relationship between long-distance dispersal behaviour of a pest-controlling money spider, Erigone atra, and the distribution of maternally acquired endosymbionts within the wider meta-population. This spider persists in heterogeneous environments because of its ability to recolonise areas through active long-distance airborne dispersal using silk as a sail, in a process termed 'ballooning'. Results We show that there is spatial heterogeneity in the prevalence of two maternally acquired endosymbiont infections within the wider E. atra meta-population and we demonstrate through several independent approaches a link between the presence of one of these endosymbionts, Rickettsia, and the tendency for long-distance movement. Conclusion This novel finding that particular endosymbionts can influence host dispersal is of broad importance given the extremely widespread occurrence of similar bacteria within arthropod communities. A bacterial phenotype that limits dispersal has the potential not only to reduce gene flow and thus contribute to degrees of reproductive isolation within species, but also to influence species distribution and thus overall community composition.

  17. Undiscovered Bat Hosts of Filoviruses

    Science.gov (United States)

    Schmidt, John Paul; Alexander, Laura W.; Bowden, Sarah E.; Hayman, David T. S.; Drake, John M.

    2016-01-01

    Ebola and other filoviruses pose significant public health and conservation threats by causing high mortality in primates, including humans. Preventing future outbreaks of ebolavirus depends on identifying wildlife reservoirs, but extraordinarily high biodiversity of potential hosts in temporally dynamic environments of equatorial Africa contributes to sporadic, unpredictable outbreaks that have hampered efforts to identify wild reservoirs for nearly 40 years. Using a machine learning algorithm, generalized boosted regression, we characterize potential filovirus-positive bat species with estimated 87% accuracy. Our model produces two specific outputs with immediate utility for guiding filovirus surveillance in the wild. First, we report a profile of intrinsic traits that discriminates hosts from non-hosts, providing a biological caricature of a filovirus-positive bat species. This profile emphasizes traits describing adult and neonate body sizes and rates of reproductive fitness, as well as species’ geographic range overlap with regions of high mammalian diversity. Second, we identify several bat species ranked most likely to be filovirus-positive on the basis of intrinsic trait similarity with known filovirus-positive bats. New bat species predicted to be positive for filoviruses are widely distributed outside of equatorial Africa, with a majority of species overlapping in Southeast Asia. Taken together, these results spotlight several potential host species and geographical regions as high-probability targets for future filovirus surveillance. PMID:27414412

  18. Properties of R1162, a broad-host-range, high-copy-number plasmid.

    OpenAIRE

    R. MEYER; Hinds, M; Brasch, M.

    1982-01-01

    Regions of plasmid DNA encoding characteristic properties of the IncQ (P-4) group plasmid R1162 were identified by mutagenesis and in vitro cloning. Coding sequences sufficient for expression of incompatibility and efficient conjugal mobilization by plasmid R751 were found to be linked to the origin of DNA replication. In contrast, there was a region remote from the origin, and active in trans, that was required for plasmid maintenance. A derivative that was temperature sensitive for stabilit...

  19. Hyperfine field distributions at 111Cd probes in nickel alloys. Pt. 1

    International Nuclear Information System (INIS)

    Hyperfine fields in dilute NiCu and NiSi alloys were measured by time differential perturbed angular correlations of 111Cd following decay of 111In. Broad featureless field distributions were observed which are related to large host moment disturbances surrounding solutes in these alloys. Mean hyperfine fields remain proportioanl to the magnetization. Studies on a NiCu alloy before and after annealing indicate repulsion between In and Cu atoms in nickel. (orig.)

  20. Web hosting for dummies

    CERN Document Server

    Pollock, Peter

    2013-01-01

    Host your own website or blog with this unique guide If you'd like to make the leap from a hosted environment to a self-hosted service, this book is for you. You may be making the move from casual blogging to professional blogging. Or, you might already be self-hosting, but want a good guide to show you how to get more out of your plan. In simple, easy-to-understand language, this helpful book breaks down all the functions of web hosting for self-hosted users, from setting up new e-mail accounts to backing up and securing your site, analyzing server logs, choosing a platform to ins

  1. Silicon micromachined broad band light source

    Science.gov (United States)

    George, Thomas (Inventor); Jones, Eric (Inventor); Tuma, Margaret L. (Inventor); Eastwood, Michael (Inventor); Hansler, Richard (Inventor)

    2004-01-01

    A micro electromechanical system (MEMS) broad band incandescent light source includes three layers: a top transmission window layer; a middle filament mount layer; and a bottom reflector layer. A tungsten filament with a spiral geometry is positioned over a hole in the middle layer. A portion of the broad band light from the heated filament is reflective off the bottom layer. Light from the filament and the reflected light of the filament are transmitted through the transmission window. The light source may operate at temperatures of 2500 K or above. The light source may be incorporated into an on board calibrator (OBC) for a spectrometer.

  2. Citrus tristeza virus-host interactions

    OpenAIRE

    Dawson, William O.; Garnsey, Stephen M.; Satyanarayana eTatineni; Folimonova, Svetlana Y.; Scott J Harper; S eGowda

    2013-01-01

    Citrus tristeza virus (CTV) is a phloem-limited virus whose natural host range is restricted to citrus and related species. Although the virus has killed millions of trees, almost destroying whole industries, and continually limits production in many citrus growing areas, most isolates are mild or symptomless in most of their host range. There is little understanding of how the virus causes severe disease in some citrus and none in others. Movement and distribution of CTV differs considerably...

  3. Rates and Properties of Type Ia Supernovae as a Function of Mass and Star Formation in Their Host Galaxies

    Science.gov (United States)

    Sullivan, M.; Le Borgne, D.; Pritchet, C. J.; Hodsman, A.; Neill, J. D.; Howell, D. A.; Carlberg, R. G.; Astier, P.; Aubourg, E.; Balam, D.; Basa, S.; Conley, A.; Fabbro, S.; Fouchez, D.; Guy, J.; Hook, I.; Pain, R.; Palanque-Delabrouille, N.; Perrett, K.; Regnault, N.; Rich, J.; Taillet, R.; Baumont, S.; Bronder, J.; Ellis, R. S.; Filiol, M.; Lusset, V.; Perlmutter, S.; Ripoche, P.; Tao, C.

    2006-09-01

    We show that Type Ia supernovae (SNe Ia) are formed within both very young and old stellar populations, with observed rates that depend on the stellar mass and mean star formation rates (SFRs) of their host galaxies. Models in which the SN Ia rate depends solely on host galaxy stellar mass are ruled out with >99% confidence. Our analysis is based on 100 spectroscopically confirmed SNe Ia, plus 24 photometrically classified events, all from the Supernova Legacy Survey (SNLS) and distributed over 0.2host galaxies by fitting their broadband spectral energy distributions with the galaxy spectral synthesis code PÉGASE.2. We show that the SN Ia rate per unit mass is proportional to the specific SFR of the parent galaxies-more vigorously star-forming galaxies host more SNe Ia per unit stellar mass, broadly equivalent to the trend of increasing SN Ia rate in later type galaxies seen in the local universe. Following earlier suggestions for a simple ``two-component'' model approximating the SN Ia rate, we find bivariate linear dependencies of the SN Ia rate on both the stellar masses and the mean SFRs of the host systems. We find that the SN Ia rate can be well represented as the sum of 5.3+/-1.1×10-14 SNe yr-1 Msolar-1 and 3.9+/-0.7×10-4 SNe yr-1 (Msolar yr-1)-1 of star formation. We also demonstrate a dependence of distant SN Ia light-curve shapes on star formation in the host galaxy, similar to trends observed locally. Passive galaxies, with no star formation, preferentially host faster declining/dimmer SNe Ia, while brighter events are found in systems with ongoing star formation.

  4. The saproxylic beetle assemblage associated with different host trees in Southwest China

    Institute of Scientific and Technical Information of China (English)

    Jie Wu; Xiao-Dong Yu; Hong-Zhang Zhou

    2008-01-01

    Dead wood is a habitat for many insects and other small animals,some of which may be rare or endangered and in need of effective protection.In this paper,saproxylic beetle assemblages associated with different host trees in the subtropical forests in southwestern China were investigated.A total of 277 species (1 439 specimens) in 36 beetle families were collected from 117 dead wood samples,of which 101 samples were identified and respectively belonged to 12 tree genera.The number of saproxylic beetle species varied greatly among logs of different tree genera,with the highest diversity on logs of Juglans.Generally,broad-leaved trees had a higher richness and abundance of saproxylic species than coniferous trees.Cluster analysis revealed that assemblages from broad-leaved tree genera were generally similar (except for Betula) and assemblages from coniferous trees formed another distinct cluster.The subsequent indicator analysis proposed that there are different characteristic species for different cluster groups of host tree genera.In our study,log diameter has no positive influence on beetle species density.Conversely,comparisons of individual-based rarefaction curves suggested that beetle species richness was highest in the small diameter class both in coniferous and broad-leaved tree genera.With increased wood decay,proportion of habitat specialists (saproxylic beetles living on one tree genus)decreased,whereas proportion of habitat generalists (living on more than three tree genera)increased.The beetle species density was found to be higher in early stages,and decreased in later stages as well.A negative influence of altitude on saproxylic beetle species richness and abundance was detected.It was indicated that different tree genera and altitudes possibly display cross effects in modulating the altitudinal distribution and host preference of the beetles.

  5. Survival analysis of the optical brightness of GRB host galaxies

    CERN Document Server

    Racz, I I; Bagoly, Z; Toth, L V

    2015-01-01

    We studied the unbiased optical brightness distribution which was calculated from the survival analysis of host galaxies and its relationship with the Swift GRB data of the host galaxies observed by the Keck telescopes. Based on the sample obtained from merging the Swift GRB table and the Keck optical data we also studied the dependence of this distribution on the data of the GRBs. Finally, we compared the HGs distribution with standard galaxies distribution which is in the DEEP2 galaxies catalog.

  6. Asymmetric spread spectrum data-hiding for Laplacian host data

    OpenAIRE

    Vila Forcen, Jose Emilio; Voloshynovskyy, Svyatoslav; Koval, Oleksiy; Pun, Thierry

    2005-01-01

    Spread spectrum (SS) or known-host-statistics technique has shown the best performance in terms of both rate of reliable communications and bit error probability at the low watermark-to-noise ratio (WNR) regime. These results were obtained assuming that the host data follows an independent and identically distributed (i.i.d.) Gaussian distribution. However, in some widely used in practical data-hiding transform domains (like wavelet or discrete cosine transform domains) the host statistics ha...

  7. The GREGOR Broad-Band Imager

    Science.gov (United States)

    von der Lühe, O.; Volkmer, R.; Kentischer, T. J.; Geißler, R.

    2012-11-01

    The design and characteristics of the Broad-Band Imager (BBI) of GREGOR are described. BBI covers the visible spectral range with two cameras simultaneously for a large field and with critical sampling at 390 nm, and it includes a mode for observing the pupil in a Foucault configuration. Samples of first-light observations are shown.

  8. Broad resonances and beta-decay

    DEFF Research Database (Denmark)

    Riisager, K.; Fynbo, H. O. U.; Hyldegaard, S.;

    2015-01-01

    Beta-decay into broad resonances gives a distorted lineshape in the observed energy spectrum. Part of the distortion arises from the phase space factor, but we show that the beta-decay matrix element may also contribute. Based on a schematic model for p-wave continuum neutron states it is argued...

  9. Hα Imaging of Nearby Seyfert Host Galaxies

    Science.gov (United States)

    Theios, Rachel L.; Malkan, Matthew A.; Ross, Nathaniel R.

    2016-05-01

    We used narrowband (Δλ = 70 Å) interference filters with the CCD imaging camera on the Nickel 1.0 m telescope at Lick Observatory to observe 31 nearby (z extinction. We separated the Hα emission line of the “nucleus” (central 100-1000 pc) from that of the host galaxy. The extended Hα emission is expected to be powered by newly formed hot stars, and indeed correlates well with other indicators of current star formation rates (SFRs) in these galaxies: extended 7.7 μm polycyclic aromatic hydrocarbon, total far-infrared, and radio luminosity. Relative to what would be expected from recent star formation, there is a 0.8 dex excess of radio emission in our Seyfert galaxies. The Hα luminosity we measured in the centers of our galaxies is dominated by the active galactic nucleus (AGN), and is linearly correlated with the hard X-ray luminosity. There is, however, an upward offset of 1 dex in this correlation for the Seyfert 1s, because their nuclear Hα emission includes a strong additional contribution from the broad-line region. We found a correlation between SFR and AGN luminosity. In spite of selection effects, we concluded that the absence of bright Seyfert nuclei in galaxies with low SFRs is real, albeit only weakly significant. Finally, we used our measured spatial distributions of Hα emission to determine what these Seyfert galaxies would look like when observed through fixed apertures (e.g., a spectroscopic fiber) at high redshifts. We found that although all of these Seyfert galaxies would be detectable emission-line galaxies at any redshift, most of them would appear to be dominated by (>67%) their H ii region emission. Only the most luminous AGNs (log(L Hα /erg s-1) > 41.5) would still be identified as such at z ˜ 0.3.

  10. Intraspecific competition in Zabrotes subfasciatus:Physiological and behavioral adaptations to different amounts of host

    Institute of Scientific and Technical Information of China (English)

    Isabel R.V. Teixeira1,2; Fernando S. Zucoloto1

    2012-01-01

    The effects of competition on populations of the bean weevil Zabrotes subfasciatus were analyzed during 41 generations under different competition levels.Three competition environments were established by maintaining the number of couples (6) and varying the amount of available host seeds:HC,high (limited availability of host:1.35 g);IC,intermediate (intermediate availability of host:6 g); and LC,low competition (abundance of host:36 g).It was found that the distribution of the eggs laid on grains was different among treatments:in LC,for example,although females showed high fecundity (35.4 ± 5.6 eggs/female) the number of eggs laid on each grain was small (1.2 ± 0.4eggs on each seed),thus avoiding larval competition of their offspring; whereas in HC treatment,females showed low fecundity (27.04 ± 4.5 eggs/female) but laid many eggs on each grain (15.03 ± 4.3 eggs).There were no changes in the ability to respond to different amounts of host via oviposition behavior (egg distribution) during 41 generations.However,HC females had more offspring than LC females under HC conditions.This suggests that HC insects evolved toward higher fitness in crowded conditions.In addition,after inverting the competition level,insects behaved independently of the treatment conditions they experienced through generations,thus showing that oviposition behavior is flexible.Taken together,our results show that Z.subfasciatus presents a broad range of behavioral and physiological responses which allows for quick and reversible adjustments to sudden changes in the amount of resources.

  11. 亚热带常绿阔叶林群落物种多度分布格局对取样尺度的响应%Responses of species-abundance distribution to varying sampling scales in a subtropical broad-leaved forest

    Institute of Scientific and Technical Information of China (English)

    程佳佳; 米湘成; 马克平; 张金屯

    2011-01-01

    We determined the best-fit model for, and explored the mechanisms shaping species-abundance distributions (SADs) by fitting five widely-used SAD distribution models at several scales.We used data collected in 2005 from a 24-ha dynamic plot in an evergreen broad-leaved forest in the Gutianshan National Nature Reserve.We estimated SAD at different sampling scales from the mean value of SADs taken from 100 randomly-selected subplots within the 600 m×400 m Gutianshan plot.We subsequently used the SADs to test the fit of different models, including the broken stick, lognormal distribution, niche preemption, Zipf,Zipf- Mandelbrot, and neutral models.We employed AIC and x2 values to test goodness-of-fit for these models.All computations were conducted using the Vegan package in R 2.7.1.At smaller scales (10 m× 10 m and 20 m×20 m), the broken stick, lognormal distribution, niche preemption, Zipf, and Zipf-Mandelbrot models all fit well to the observed species-abundance distribution.The Zipf-Mandelbrot was the best model at the 20 m×20 m scale.The Lognormal was the best-fit model at the 40 m×40 m scale, and the Zipf-Mandelbrot model was the only suitable one in explaining the observed SAD at scales of 60 m×60 m and 80 m×80 m.None of these models performed well at a scale of 100 m× 100 m, but the neutral model was better at explaining patterns of SADs at larger scales (40 m×40 m to 100 m× 100 m) than smaller scales and it is suitable in explaining patterns of SADs at all scales.Patterns in SAD were scale-dependent, suggesting that SADs at different scales are likely structured by different ecological processes.%为揭示物种多度格局随尺度的变化规律,探讨多度格局形成的机理及生态学过程,作者以古田山亚热带常绿阔叶林24 ha固定监测样地为背景.采用断棍模型(broken stick model)、对数正态模型(Iognormal distribution model)、生态位优先占领模型(preemption model)、Zipf模型(Zipf model

  12. Species formation by host shifting in avian malaria parasites.

    Science.gov (United States)

    Ricklefs, Robert E; Outlaw, Diana C; Svensson-Coelho, Maria; Medeiros, Matthew C I; Ellis, Vincenzo A; Latta, Steven

    2014-10-14

    The malaria parasites (Apicomplexa: Haemosporida) of birds are believed to have diversified across the avian host phylogeny well after the origin of most major host lineages. Although many symbionts with direct transmission codiversify with their hosts, mechanisms of species formation in vector-borne parasites, including the role of host shifting, are poorly understood. Here, we examine the hosts of sister lineages in a phylogeny of 181 putative species of malaria parasites of New World terrestrial birds to determine the role of shifts between host taxa in the formation of new parasite species. We find that host shifting, often across host genera and families, is the rule. Sympatric speciation by host shifting would require local reproductive isolation as a prerequisite to divergent selection, but this mechanism is not supported by the generalized host-biting behavior of most vectors of avian malaria parasites. Instead, the geographic distribution of individual parasite lineages in diverse hosts suggests that species formation is predominantly allopatric and involves host expansion followed by local host-pathogen coevolution and secondary sympatry, resulting in local shifting of parasite lineages across hosts.

  13. Screening and analysis of genes expressed upon infection of broad bean with Clover yellow vein virus causing lethal necrosis

    OpenAIRE

    Suzuki Yuji; Choi Sun; Atsumi Go; Kitazawa Hiroaki; Nakahara Kenji S; Uyeda Ichiro

    2011-01-01

    Abstract Clover yellow vein virus (ClYVV) causes lethal systemic necrosis in legumes, including broad bean (Vicia faba) and pea (Pisum sativum). To identify host genes involved in necrotic symptom expression after ClYVV infection, we screened cDNA fragments in which expression was changed in advance of necrotic symptom expression in broad bean (V. faba cv. Wase) using the differential display technique and secondarily with Northern blot analysis. Expression changes were confirmed in 20 genes,...

  14. Broad iron lines in Active Galactic Nuclei

    CERN Document Server

    Fabian, A C; Reynolds, C S; Young, A J

    2000-01-01

    An intrinsically narrow line emitted by an accretion disk around a black hole appears broadened and skewed as a result of the Doppler effect and gravitational redshift. The fluorescent iron line in the X-ray band at 6.4-6.9keV is the strongest such line and is seen in the X-ray spectrum of many active galactic nuclei and, in particular, Seyfert galaxies. It is an important diagnostic with which to study the geometry and other properties of the accretion flow very close to the central black hole. The broad iron line indicates the presence of a standard thin accretion disk in those objects, often seen at low inclination. The broad iron line has opened up strong gravitational effects around black holes to observational study with wide-reaching consequences for both astrophysics and physics.

  15. Broad line regions in Seyfert-1 galaxies

    International Nuclear Information System (INIS)

    To reproduce observed emission profiles of Seyfert galaxies, rotation in an accretion disk has been proposed. In this thesis, the profiles emitted by such an accretion disk are investigated. Detailed comparison with the observed profiles yields that a considerable fraction can be fitted with a power-law function, as predicted by the model. The author analyzes a series of high quality spectra of Seyfert galaxies, obtained with the 2.5m telescope at Las Campanas. He presents detailed analyses of two objects: Mkn335 and Akn120. In both cases, strong evidence is presented for the presence of two separate broad line zones. These zones are identified with an accretion disk and an outflowing wind. The disk contains gas with very high densities and emits predominantly the lower ionization lines. He reports on the discovery of very broad wings beneath the strong forbidden line 5007. (Auth.)

  16. Crx broadly modulates the pineal transcriptome

    OpenAIRE

    Rovsing, Louise; Clokie, Samuel; Bustos, Diego M.; Rohde, Kristian; Steven L Coon; Litman, Thomas; Rath, Martin F.; Møller, Morten; Klein, David C.

    2011-01-01

    Cone-rod homeobox (Crx) encodes Crx, a transcription factor expressed selectively in retinal photoreceptors and pinealocytes, the major cell type of the pineal gland. Here, the influence of Crx on the mammalian pineal gland was studied by light and electron microscopy and by use of microarray and qRTPCR technology, thereby extending previous studies on selected genes (Furukawa et al. 1999). Deletion of Crx was not found to alter pineal morphology, but was found to broadly modulate the mouse p...

  17. A Broad View of Macroeconomic Stability

    OpenAIRE

    José Antonio Ocampo

    2005-01-01

    This paper recommends a broad concept of macroeconomic stability, whereby “sound macroeconomic frameworks” include not only price stability and sound fiscal policies, but also a well-functioning real economy, sustainable debt ratios and healthy public and private sector balance sheets. These multiple dimensions imply using multiple policy instruments. The paper elaborates a framework for developing countries that involves active use of counter-cyclical macroeconomic policies (exchange rate, m...

  18. Relativistic redshifts in quasar broad lines

    CERN Document Server

    Tremaine, Scott; Liu, Xin; Loeb, Abraham

    2014-01-01

    The broad emission lines commonly seen in quasar spectra have velocity widths of a few per cent of the speed of light, so special- and general-relativistic effects have a significant influence on the line profile. We have determined the redshift of the broad H-beta line in the quasar rest frame (determined from the core component of the [OIII] line) for over 20,000 quasars from the Sloan Digital Sky Survey DR7 quasar catalog. The mean redshift as a function of line width is approximately consistent with the relativistic redshift that is expected if the line originates in a randomly oriented Keplerian disk that is obscured when the inclination of the disk to the line of sight exceeds ~30-45 degrees, consistent with simple AGN unification schemes. This result also implies that the net line-of-sight inflow/outflow velocities in the broad-line region are much less than the Keplerian velocity when averaged over a large sample of quasars with a given line width.

  19. Squalamine as a broad-spectrum systemic antiviral agent with therapeutic potential

    OpenAIRE

    Zasloff, Michael; Adams, A. Paige; Beckerman, Bernard; Campbell, Ann; Han, Ziying; Luijten, Erik; Meza, Isaura; Julander, Justin; Mishra, Abhijit; Qu, Wei; Taylor, John M; Scott C Weaver; Wong, Gerard C. L.

    2011-01-01

    Antiviral compounds that increase the resistance of host tissues represent an attractive class of therapeutic. Here, we show that squalamine, a compound previously isolated from the tissues of the dogfish shark (Squalus acanthias) and the sea lamprey (Petromyzon marinus), exhibits broad-spectrum antiviral activity against human pathogens, which were studied in vitro as well as in vivo. Both RNA- and DNA-enveloped viruses are shown to be susceptible. The proposed mechanism involves the capacit...

  20. To Broad-Match or Not to Broad-Match : An Auctioneer's Dilemma ?

    CERN Document Server

    Singh, Sudhir Kumar

    2008-01-01

    We initiate the study of an interesting aspect of sponsored search advertising, namely the consequences of broad match-a feature where an ad of an advertiser can be mapped to a broader range of relevant queries, and not necessarily to the particular keyword(s) that ad is associated with. Starting with a very natural setting for strategies available to the advertisers, and via a careful look through algorithmic and complexity theoretic glasses, we first propose a solution concept called broad match equilibrium(BME) for the game originating from the strategic behavior of advertisers as they try to optimize their budget allocation across various keywords. Next, we consider two broad match scenarios based on factors such as information asymmetry between advertisers and the auctioneer, and the extent of auctioneer's control on the budget splitting. In the first scenario, the advertisers have the full information about broad match and relevant parameters, and can reapportion their own budgets to utilize the extra i...

  1. The HIV glycan shield as a target for broadly neutralizing antibodies.

    Science.gov (United States)

    Doores, Katie J

    2015-12-01

    The HIV envelope glycoprotein (Env) is the sole target for HIV broadly neutralizing antibodies (bnAbs). HIV Env is one of the most heavily glycosylated proteins known, with approximately half of its mass consisting of host-derived N-linked glycans. The high density of glycans creates a shield that impedes antibody recognition but, critically, some of the most potent and broadly active bnAbs have evolved to recognize epitopes formed by these glycans. Although the virus hijacks the host protein synthesis and glycosylation machinery to generate glycosylated HIV Env, studies have shown that HIV Env glycosylation diverges from that typically observed on host-derived glycoproteins. In particular, the high density of glycans leads to a nonself motif of underprocessed oligomannose-type glycans that forms the target of some of the most broad and potent HIV bnAbs. This review discusses the changing perception of the HIV glycan shield, and summarizes the protein-directed and cell-directed factors controlling HIV Env glycosylation that impact on HIV bnAb recognition and HIV vaccine design strategies.

  2. Broad surveys of DNA viral diversity obtained through viral metagenomics of mosquitoes.

    Directory of Open Access Journals (Sweden)

    Terry Fei Fan Ng

    Full Text Available Viruses are the most abundant and diverse genetic entities on Earth; however, broad surveys of viral diversity are hindered by the lack of a universal assay for viruses and the inability to sample a sufficient number of individual hosts. This study utilized vector-enabled metagenomics (VEM to provide a snapshot of the diversity of DNA viruses present in three mosquito samples from San Diego, California. The majority of the sequences were novel, suggesting that the viral community in mosquitoes, as well as the animal and plant hosts they feed on, is highly diverse and largely uncharacterized. Each mosquito sample contained a distinct viral community. The mosquito viromes contained sequences related to a broad range of animal, plant, insect and bacterial viruses. Animal viruses identified included anelloviruses, circoviruses, herpesviruses, poxviruses, and papillomaviruses, which mosquitoes may have obtained from vertebrate hosts during blood feeding. Notably, sequences related to human papillomaviruses were identified in one of the mosquito samples. Sequences similar to plant viruses were identified in all mosquito viromes, which were potentially acquired through feeding on plant nectar. Numerous bacteriophages and insect viruses were also detected, including a novel densovirus likely infecting Culex erythrothorax. Through sampling insect vectors, VEM enables broad survey of viral diversity and has significantly increased our knowledge of the DNA viruses present in mosquitoes.

  3. Proteomics inference of genes involved in host adaptation of Mycoplasma gallinarum

    Science.gov (United States)

    Different from most other host-specific mycoplasmas, Mycoplasma gallinarum has been isolated from various hosts, such as poultry, pig, cattle, and sheep. The wide distribution among different hosts, the low pathogenesis, and the weak host immunological responses suggest this mycoplasma has a unique ...

  4. A spatial model of mosquito host-seeking behavior.

    Directory of Open Access Journals (Sweden)

    Bree Cummins

    Full Text Available Mosquito host-seeking behavior and heterogeneity in host distribution are important factors in predicting the transmission dynamics of mosquito-borne infections such as dengue fever, malaria, chikungunya, and West Nile virus. We develop and analyze a new mathematical model to describe the effect of spatial heterogeneity on the contact rate between mosquito vectors and hosts. The model includes odor plumes generated by spatially distributed hosts, wind velocity, and mosquito behavior based on both the prevailing wind and the odor plume. On a spatial scale of meters and a time scale of minutes, we compare the effectiveness of different plume-finding and plume-tracking strategies that mosquitoes could use to locate a host. The results show that two different models of chemotaxis are capable of producing comparable results given appropriate parameter choices and that host finding is optimized by a strategy of flying across the wind until the odor plume is intercepted. We also assess the impact of changing the level of host aggregation on mosquito host-finding success near the end of the host-seeking flight. When clusters of hosts are more tightly associated on smaller patches, the odor plume is narrower and the biting rate per host is decreased. For two host groups of unequal number but equal spatial density, the biting rate per host is lower in the group with more individuals, indicative of an attack abatement effect of host aggregation. We discuss how this approach could assist parameter choices in compartmental models that do not explicitly model the spatial arrangement of individuals and how the model could address larger spatial scales and other probability models for mosquito behavior, such as Lévy distributions.

  5. Scale insect host ranges are broader in the tropics.

    Science.gov (United States)

    Hardy, Nate B; Peterson, Daniel A; Normark, Benjamin B

    2015-12-01

    The specificity of the interactions between plants and their consumers varies considerably. The evolutionary and ecological factors underlying this variation are unclear. Several potential explanatory factors vary with latitude, for example plant species richness and the intensity of herbivory. Here, we use comparative phylogenetic methods to test the effect of latitude on host range in scale insects. We find that, on average, scale insects that occur in lower latitudes are more polyphagous. This result is at odds with the general pattern of greater host-plant specificity of insects in the tropics. We propose that this disparity reflects a high cost for host specificity in scale insects, stemming from unusual aspects of scale insect life history, for example, passive wind-driven dispersal. More broadly, the strong evidence for pervasive effects of geography on host range across insect groups stands in stark contrast to the weak evidence for constraints on host range due to genetic trade-offs.

  6. Pseudorhabdosynochus sulamericanus (Monogenea, Diplectanidae), a parasite of deep-sea groupers (Serranidae) occurs transatlantically on three congeneric hosts (Hyporthodus spp.), one from the Mediterranean Sea and two from the western Atlantic.

    Science.gov (United States)

    Chaabane, Amira; Justine, Jean-Lou; Gey, Delphine; Bakenhaster, Micah D; Neifar, Lassad

    2016-01-01

    Little is known of the diversity of the monogenean parasites infesting deep-sea groupers, and there is even less information available about their geographic distributions within the ranges of their hosts. To improve our understanding of these host-parasite relationships we conducted parasitological evaluations of the deep-water Haifa grouper Hyporthodus haifensis from the southern Mediterranean off Tunisia and Libya. We collected more than one species of diplectanid monogeneans from this host, but among these only one dominant species was abundant. This proved to be morphologically very similar to Pseudorhabdosynochus sulamericanus Santos, Buchmann & Gibson, 2000, a species originally described from the congeneric host H. niveatus off Brazil and also recorded from H. niveatus and H. nigritus off Florida. Here, we conducted a morphological comparison between newly collected specimens and those previously deposited in museum collections by other authors. Further, we used COI barcoding to ascertain the specific identity of the three host species to better elucidate the circumstances that might explain the unexpectedly broad distribution of P. sulamericanus. We assigned our specimens from H. haifensis to P. sulamericanus primarily on the basis of morphological characteristics of the sclerotized vagina. We also noted morphological characteristics of eastern and western Atlantic specimens that are not clearly described or not given in previous descriptions and so prepared a redescription of the species. We confirmed, by COI barcoding, that no sister-species relationships were evident among the three hosts of P. sulamericanus. Our observation that P. sulamericanus infects unrelated host species with putatively allopatric distributions was unexpected given the very limited dispersive capabilities and the high degree of host specificity common to members of Pseudorhabdosynochus. This transatlantic distribution raises questions with regard to phylogeography and assumptions

  7. Pseudorhabdosynochus sulamericanus (Monogenea, Diplectanidae), a parasite of deep-sea groupers (Serranidae) occurs transatlantically on three congeneric hosts (Hyporthodus spp.), one from the Mediterranean Sea and two from the western Atlantic.

    Science.gov (United States)

    Chaabane, Amira; Justine, Jean-Lou; Gey, Delphine; Bakenhaster, Micah D; Neifar, Lassad

    2016-01-01

    Little is known of the diversity of the monogenean parasites infesting deep-sea groupers, and there is even less information available about their geographic distributions within the ranges of their hosts. To improve our understanding of these host-parasite relationships we conducted parasitological evaluations of the deep-water Haifa grouper Hyporthodus haifensis from the southern Mediterranean off Tunisia and Libya. We collected more than one species of diplectanid monogeneans from this host, but among these only one dominant species was abundant. This proved to be morphologically very similar to Pseudorhabdosynochus sulamericanus Santos, Buchmann & Gibson, 2000, a species originally described from the congeneric host H. niveatus off Brazil and also recorded from H. niveatus and H. nigritus off Florida. Here, we conducted a morphological comparison between newly collected specimens and those previously deposited in museum collections by other authors. Further, we used COI barcoding to ascertain the specific identity of the three host species to better elucidate the circumstances that might explain the unexpectedly broad distribution of P. sulamericanus. We assigned our specimens from H. haifensis to P. sulamericanus primarily on the basis of morphological characteristics of the sclerotized vagina. We also noted morphological characteristics of eastern and western Atlantic specimens that are not clearly described or not given in previous descriptions and so prepared a redescription of the species. We confirmed, by COI barcoding, that no sister-species relationships were evident among the three hosts of P. sulamericanus. Our observation that P. sulamericanus infects unrelated host species with putatively allopatric distributions was unexpected given the very limited dispersive capabilities and the high degree of host specificity common to members of Pseudorhabdosynochus. This transatlantic distribution raises questions with regard to phylogeography and assumptions

  8. 肺炎克雷伯菌中超广谱β-内酰胺酶基因分布及转移研究%The distribution and transfer of genes of duper broad-spectrumβ-lactamase in klebsiella pneumoniae

    Institute of Scientific and Technical Information of China (English)

    卢锋

    2014-01-01

    目的:研究肺炎克雷伯菌中超广谱β-内酰胺酶(ESBLs)基因类型及转移方式。方法回顾性分析该院2011年1月至2013年1月收集的460例住院患者菌株的临床资料,并对其ESBLs基因进行分型和研究耐药性。结果460株β-内酰胺酶的KPN检出6种β-内酰胺酶基因,其中bla TEM占总数的5%,bla SHV占总数的20%, bla CTX-M-1群占总数的5%,bla CTX-M-9群占总数的25%,bla OXA-1群占总数的10%,bla DHA 占总数的30%等;本研究共发现322种菌株耐药谱,菌株耐药在9种抗菌药物以上。阿莫西林/替卡西林/头孢噻吩等、阿莫西林/克拉维酸和头孢西丁、哌拉西林/克拉维酸、亚胺培南的耐药性分别为100%、60%、45%、35%和0。结论肺炎克雷伯菌中ESBLs基因类型主要是bla TEM和bla CTX-M-1,并具有较为严重的耐药性。%Objective To study the distribution and transfer of genes of super broad-spectrum β-lactamase (ESBL s) in klebsiella pneumoniae .Methods The information of 460 strains of hospitalized patients who had been treated in our hospital from January 2011 to January 2013 were retrospectively analyzed .Results 460 β-lactamase KPN detected six kinds of β-lactamase gene ,which bla TEM of the total 5% ,bla SHV accounted for 20% ,bla CTX-M-1 group accounted for 5% ,bla CTX-M-9 group accounted for 25% ,bla OXA-1 group accounted for 10% ,bla DHA 30% of the total ,etc .;this study found that 322 strains resistant spectrum ,strains resistant to antibiotics in 9 above .Amoxicillin/ticarcillin/cephalosporin thiophene ,amoxicillin/clavulanic acid ,cefoxitin ,piperacillin/clavulanic acid ,imipenem were 100% ,60% ,45% ,35% and 0 .Conclusion Klebsiella pneumoniae Super spectrum β-lactamase gene type are primarily bla TEM and bla CTX-M-1 ,they have more serious resistance .

  9. Salmonella-host interactions - modulation of the host innate immune system

    Directory of Open Access Journals (Sweden)

    Daniel eHurley

    2014-10-01

    Full Text Available Salmonella enterica (S. enterica are Gram-negative bacteria that can invade a broad range of hosts causing both acute and chronic infections. This phenotype is related to its ability to replicate and persist within non-phagocytic host epithelial cells as well as phagocytic dendritic cells and macrophages of the innate immune system.Infection with S. enterica manifests itself through a broad range of clinical symptoms and can result in asymptomatic carriage, gastroenteritis, systemic disease such as typhoid fever and in severe cases, death (Gunn et al. 2014. Exposure to S. enterica serovars Typhi and Paratyphi exhibits clinical symptoms including diarrhoea, fatigue, fever and temperature fluctuations. Other serovars such as the non-typhoidal Salmonella (NTS, of which there are over 2,500, are commonly contracted as, but not limited to, food-borne sources causing gastrointestinal symptoms, which include diarrhoea and vomiting.The availability of complete genome sequences for many S. enterica serovars has facilitated research into the genetic determinants of virulence for this pathogen. This work has led to the identification of important bacterial components, including flagella, type III secretion systems, lipopolysaccharides and Salmonella pathogenicity islands, all of which support the intracellular life cycle of S. enterica. Studies focusing on the host-pathogen interaction have provided insights into receptor activation of the innate immune system. Therefore, characterising the host-S. enterica interaction is critical to understand the pathogenicity of the bacteria in a clinically relevant context. This review outlines salmonellosis and the clinical manifestations between typhoidal and NTS infections as well as discussing the host immune response to infection and the models that are being used to elucidate the mechanisms involved on Salmonella pathogenicity.

  10. Salmonella-host interactions - modulation of the host innate immune system.

    Science.gov (United States)

    Hurley, Daniel; McCusker, Matthew P; Fanning, Séamus; Martins, Marta

    2014-01-01

    Salmonella enterica (S. enterica) are Gram-negative bacteria that can invade a broad range of hosts causing both acute and chronic infections. This phenotype is related to its ability to replicate and persist within non-phagocytic host epithelial cells as well as phagocytic dendritic cells and macrophages of the innate immune system. Infection with S. enterica manifests itself through a broad range of clinical symptoms and can result in asymptomatic carriage, gastroenteritis, systemic disease such as typhoid fever and in severe cases, death (1). Exposure to S. enterica serovars Typhi and Paratyphi exhibits clinical symptoms including diarrhea, fatigue, fever, and temperature fluctuations. Other serovars such as the non-typhoidal Salmonella (NTS), of which there are over 2,500, are commonly contracted as, but not limited to, food-borne sources causing gastrointestinal symptoms, which include diarrhea and vomiting. The availability of complete genome sequences for many S. enterica serovars has facilitated research into the genetic determinants of virulence for this pathogen. This work has led to the identification of important bacterial components, including flagella, type III secretion systems, lipopolysaccharides, and Salmonella pathogenicity islands, all of which support the intracellular life cycle of S. enterica. Studies focusing on the host-pathogen interaction have provided insights into receptor activation of the innate immune system. Therefore, characterizing the host-S. enterica interaction is critical to understand the pathogenicity of the bacteria in a clinically relevant context. This review outlines salmonellosis and the clinical manifestations between typhoidal and NTS infections as well as discussing the host immune response to infection and the models that are being used to elucidate the mechanisms involved in Salmonella pathogenicity.

  11. Hepatitis C virus host cell interactions uncovered

    DEFF Research Database (Denmark)

    Gottwein, Judith; Bukh, Jens

    2007-01-01

      Insights into virus-host cell interactions as uncovered by Randall et al. (1) in a recent issue of PNAS further our understanding of the hepatitis C virus (HCV) life cycle, persistence, and pathogenesis and might lead to the identification of new therapeutic targets. HCV persistently infects 180...... treated. Therefore, there is a pressing need for the identification of novel drugs against hepatitis C. Although most research focuses on the development of HCV-specific antivirals, such as protease and polymerase inhibitors (3), cellular targets could be pursued and might allow the development of broad...

  12. Host Responses to Biofilm.

    Science.gov (United States)

    Watters, C; Fleming, D; Bishop, D; Rumbaugh, K P

    2016-01-01

    From birth to death the human host immune system interacts with bacterial cells. Biofilms are communities of microbes embedded in matrices composed of extracellular polymeric substance (EPS), and have been implicated in both the healthy microbiome and disease states. The immune system recognizes many different bacterial patterns, molecules, and antigens, but these components can be camouflaged in the biofilm mode of growth. Instead, immune cells come into contact with components of the EPS matrix, a diverse, hydrated mixture of extracellular DNA (bacterial and host), proteins, polysaccharides, and lipids. As bacterial cells transition from planktonic to biofilm-associated they produce small molecules, which can increase inflammation, induce cell death, and even cause necrosis. To survive, invading bacteria must overcome the epithelial barrier, host microbiome, complement, and a variety of leukocytes. If bacteria can evade these initial cell populations they have an increased chance at surviving and causing ongoing disease in the host. Planktonic cells are readily cleared, but biofilms reduce the effectiveness of both polymorphonuclear neutrophils and macrophages. In addition, in the presence of these cells, biofilm formation is actively enhanced, and components of host immune cells are assimilated into the EPS matrix. While pathogenic biofilms contribute to states of chronic inflammation, probiotic Lactobacillus biofilms cause a negligible immune response and, in states of inflammation, exhibit robust antiinflammatory properties. These probiotic biofilms colonize and protect the gut and vagina, and have been implicated in improved healing of damaged skin. Overall, biofilms stimulate a unique immune response that we are only beginning to understand. PMID:27571696

  13. Mechanisms of submicron inclusion re-equilibration during host mineral deformation

    Science.gov (United States)

    Griffiths, Thomas; Habler, Gerlinde; Abart, Rainer; Rhede, Dieter; Wirth, Richard

    2014-05-01

    Both brittle and ductile deformation can facilitate re-equilibration of mineral inclusions. The presence of inclusions also influences stress and strain distribution in the host. The processes governing feedbacks between brittle deformation, ductile deformation, and inclusion re-equilibration have been studied using unique microstructures in Permian meta-pegmatite garnets from the Koralpe, Eastern Alps, Austria. Sampled almandine-spessartine garnets contain highly abundant submicron-sized inclusions, which originated during or subsequent to magmatic garnet growth. The Permian magmatic assemblages were affected by eclogite facies metamorphism during the Cretaceous tectono-metamorphic event. The meta-pegmatite garnet deformed crystal-plastically at this metamorphic stage (Bestmann et al. 2008) and the host-inclusion system was affected by partial recrystallization. Trails of coarser inclusions (1-10µm diameter) crosscut the magmatic submicron inclusion density zoning in the garnet, defining curviplanar geometrical surfaces in 3D. In 10-40µm broad 'bleaching zones' flanking inclusion trails, the original ≤1µm sized inclusions are not seen in the optical microscope or SEM, however inclusions pipe diffusion along introduced dislocations. Later ductile deformation via dislocations, concentrated at already coarsened inclusions and enhanced by fluid availability, further affected the nanoinclusion population. The inclusion trail microstructure records complex small-scale interaction between deformation and reaction, shedding light on the mechanisms by which re-equilibration and strain localisation can influence each other in deforming host-inclusion systems. Bestmann et al. (2008) Journal of Structural Geology 30: 777-790

  14. Early-season host switching in Adelphocoris spp. (Hemiptera: Miridae of differing host breadth.

    Directory of Open Access Journals (Sweden)

    Hongsheng Pan

    Full Text Available The mirid bugs Adelphocoris suturalis (Jakovlev, Adelphocoris lineolatus (Goeze and Adelphocoris fasciaticollis (Reuter (Hemiptera: Miridae are common pests of several agricultural crops. These three species have vastly different geographical distributions, phenologies and abundances, all of which are linked to their reliance on local plants. Previous work has shown notable differences in Adelphocoris spp. host use for overwintering. In this study, we assessed the extent to which each of the Adelphocoris spp. relies on some of its major overwinter hosts for spring development. Over the course of four consecutive years (2009-2012, we conducted population surveys on 77 different plant species from 39 families. During the spring, A. fasciaticollis used the broadest range of hosts, as it was found on 35 plant species, followed by A. suturalis (15 species and A. lineolatus (7 species. Abundances of the species greatly differed between host plants, with A. fasciaticollis reaching the highest abundance on Chinese date (Ziziphus jujuba Mill., whereas both A. suturalis and A. lineolatus preferred alfalfa (Medicago sativa L.. The host breadths of the three Adelphocoris spp. differed greatly between subsequent spring and winter seasons. The generalist species exhibited the least host fidelity, with A. suturalis and A. lineolatus using 8 of 22 and 4 of 12 overwinter host species for spring development, respectively. By contrast, the comparative specialist A. fasciaticollis relied on 9 of its 11 overwinter plants as early-season hosts. We highlight important seasonal changes in host breadth and interspecific differences in the extent of host switching behavior between the winter and spring seasons. These findings benefit our understanding of the evolutionary interactions between mirid bugs and their host plants and can be used to guide early-season population management.

  15. Rainbow Vectors for Broad-Range Bacterial Fluorescence Labeling.

    Directory of Open Access Journals (Sweden)

    Mariette Barbier

    Full Text Available Since their discovery, fluorescent proteins have been widely used to study protein function, localization or interaction, promoter activity and regulation, drug discovery or for non-invasive imaging. They have been extensively modified to improve brightness, stability, and oligomerization state. However, only a few studies have focused on understanding the dynamics of fluorescent proteins expression in bacteria. In this work, we developed a set plasmids encoding 12 fluorescent proteins for bacterial labeling to facilitate the study of pathogen-host interactions. These broad-spectrum plasmids can be used with a wide variety of Gram-negative microorganisms including Escherichia coli, Pseudomonas aeruginosa, Burkholderia cepacia, Bordetella bronchiseptica, Shigella flexneri or Klebsiella pneumoniae. For comparison, fluorescent protein expression and physical characteristics in Escherichia coli were analyzed using fluorescence microscopy, flow cytometry and in vivo imaging. Fluorescent proteins derived from the Aequorea Victoria family showed high photobleaching, while proteins form the Discosoma sp. and the Fungia coccina family were more photostable for microscopy applications. Only E2-Crimson, mCherry and mKeima were successfully detected for in vivo applications. Overall, E2-Crimson was the fastest maturing protein tested in E. coli with the best overall performance in the study parameters. This study provides a unified comparison and comprehensive characterization of fluorescent protein photostability, maturation and toxicity, and offers general recommendations on the optimal fluorescent proteins for in vitro and in vivo applications.

  16. Rainbow Vectors for Broad-Range Bacterial Fluorescence Labeling.

    Science.gov (United States)

    Barbier, Mariette; Damron, F Heath

    2016-01-01

    Since their discovery, fluorescent proteins have been widely used to study protein function, localization or interaction, promoter activity and regulation, drug discovery or for non-invasive imaging. They have been extensively modified to improve brightness, stability, and oligomerization state. However, only a few studies have focused on understanding the dynamics of fluorescent proteins expression in bacteria. In this work, we developed a set plasmids encoding 12 fluorescent proteins for bacterial labeling to facilitate the study of pathogen-host interactions. These broad-spectrum plasmids can be used with a wide variety of Gram-negative microorganisms including Escherichia coli, Pseudomonas aeruginosa, Burkholderia cepacia, Bordetella bronchiseptica, Shigella flexneri or Klebsiella pneumoniae. For comparison, fluorescent protein expression and physical characteristics in Escherichia coli were analyzed using fluorescence microscopy, flow cytometry and in vivo imaging. Fluorescent proteins derived from the Aequorea Victoria family showed high photobleaching, while proteins form the Discosoma sp. and the Fungia coccina family were more photostable for microscopy applications. Only E2-Crimson, mCherry and mKeima were successfully detected for in vivo applications. Overall, E2-Crimson was the fastest maturing protein tested in E. coli with the best overall performance in the study parameters. This study provides a unified comparison and comprehensive characterization of fluorescent protein photostability, maturation and toxicity, and offers general recommendations on the optimal fluorescent proteins for in vitro and in vivo applications. PMID:26937640

  17. Distribution patterns and carbon and nitrogen contents of Castanopsis platyacantha fine roots, the constructive species of evergreen broad-leaved secondary forest in Wawushan Mountain of Sichuan Province%瓦屋山常绿阔叶次生林建群种扁刺栲的细根分布及其碳氮特征

    Institute of Scientific and Technical Information of China (English)

    彭勇; 陈冠陶; 梁政; 李顺; 彭天驰; 涂利华

    2016-01-01

    The Wawushan Mountain National Forest Park in Sichuan Province, where there is relatively intact Castanopsis platyacantha-Schima sinensis formations, is a typical representative of the mid-subtropical moist evergreen broad-leaved forest in West China. Using the soil core method, this study investigated the fine root distribution and characteristics of carbon and nitrogen of sample C. platyacantha which is the main constructive species in this formation. The results were as follows: (1) The total fine root biomass of C. platyacantha was 173.62 g·m?2 and the total biomass of live fine roots was 135.29 g·m?2. (2) The fine root biomass, root length density, root surface area and specific root length decreased with the increase of soil depth, and their proportions in 0-30 cm layers were 67.23%, 69.53%, 69.48%and 57.20%, respectively; root length density, root surface area and specific root length decreased significantly with increasing root diameter, and 58.84%, 52.59%and 51.36%of them were in the roots that diameter was less than 1 mm, respectively. (3) Root extinction coefficient in biomass, length and surface area of C. platyacantha fine root increased with the rise of the root diameter. (4) In the first soil layer, the roots C content increased significantly with the rising root diameter, but there was no significant difference in other soil layers;the C content of the roots whose diameter was less than 2 mm in the first soil layer was significantly lower than other soil layers, while the differences of roots C content of greater than 2 mm among soil layers was insignificant. (5) The roots N content decreased with the increase of soil depth and root diameter, while the C/N ratio value was opposite. These results reflected the vertical distribution of the secondary forest underground fine root system and nutrient characteristics, which would provided some basic data for revealing the subsurface ecological processes and the effects of environmental change on

  18. Parasite host range and the evolution of host resistance

    NARCIS (Netherlands)

    Gorter, F.A.; Hall, A.R.; A., Buckling; P.D., Scanlan

    2015-01-01

    Parasite host range plays a pivotal role in the evolution and ecology of hosts
    and the emergence of infectious disease. Although the factors that promote
    host range and the epidemiological consequences of variation in host range
    are relatively well characterized, the effect of parasite h

  19. Parasite host range and the evolution of host resistance.

    Science.gov (United States)

    Gorter, F A; Hall, A R; Buckling, A; Scanlan, P D

    2015-05-01

    Parasite host range plays a pivotal role in the evolution and ecology of hosts and the emergence of infectious disease. Although the factors that promote host range and the epidemiological consequences of variation in host range are relatively well characterized, the effect of parasite host range on host resistance evolution is less well understood. In this study, we tested the impact of parasite host range on host resistance evolution. To do so, we used the host bacterium Pseudomonas fluorescens SBW25 and a diverse suite of coevolved viral parasites (lytic bacteriophage Φ2) with variable host ranges (defined here as the number of host genotypes that can be infected) as our experimental model organisms. Our results show that resistance evolution to coevolved phages occurred at a much lower rate than to ancestral phage (approximately 50% vs. 100%), but the host range of coevolved phages did not influence the likelihood of resistance evolution. We also show that the host range of both single parasites and populations of parasites does not affect the breadth of the resulting resistance range in a naïve host but that hosts that evolve resistance to single parasites are more likely to resist other (genetically) more closely related parasites as a correlated response. These findings have important implications for our understanding of resistance evolution in natural populations of bacteria and viruses and other host-parasite combinations with similar underlying infection genetics, as well as the development of phage therapy. PMID:25851735

  20. Virus evolution in the face of the host response

    International Nuclear Information System (INIS)

    Full text: Microbial infections are highly dynamic processes in which the invading pathogen must counteract host responses to complete an infectious cycle. Viruses offer a broad repertoire of strategies to cope with host defences. Complex DNA viruses encode a number of immunomodulatory proteins aimed at interacting with the host to modulate host responses. In contrast with this 'interacting' strategy, the highly variable RNA viruses employ an 'evasion' strategy, with the frequent selection of mutants capable of evading host immune responses. Mutation rates for RNA viruses are in the range of 10-3 to 10-5 misincorporations per nucleotide copied. This continuous mutational input has as a result that viral genome populations do not consist of a defined nucleotide sequence but of multitudes of closely related sequences. The entire mutant distribution is termed a viral quasispecies. The spectrum of mutants serves as a reservoir of genetic and phenotypic variants. The continuous replenishment of this dynamic reservoir constitutes an adaptative strategy for RNA viruses since selective pressures can result in dominance of viral subpopulations that were a minority in the parental distribution of mutants. Quasispecies adaptability is reflected not only in evasion of immune responses but also in changes in cell tropism and host range of viruses, with implications for viral disease emergence and re-emergence. Several examples of human and animal viruses in which quasispecies dynamics plays a role in viral persistence and disease progression will be discussed. Quasispecies dynamics has additional implications for virus evolution, the diagnosis of viral disease and the design of preventive and therapeutic strategies. Viral populations can contain a memory of those genomes that were dominant at an earlier stage of their evolutionary history. This is a genetic memory in the form of minority components of the mutant spectrum, first described with two independent lineages of foot

  1. Broad spectrum microarray for fingerprint-based bacterial species identification

    Directory of Open Access Journals (Sweden)

    Frey Jürg E

    2010-02-01

    Full Text Available Abstract Background Microarrays are powerful tools for DNA-based molecular diagnostics and identification of pathogens. Most target a limited range of organisms and are based on only one or a very few genes for specific identification. Such microarrays are limited to organisms for which specific probes are available, and often have difficulty discriminating closely related taxa. We have developed an alternative broad-spectrum microarray that employs hybridisation fingerprints generated by high-density anonymous markers distributed over the entire genome for identification based on comparison to a reference database. Results A high-density microarray carrying 95,000 unique 13-mer probes was designed. Optimized methods were developed to deliver reproducible hybridisation patterns that enabled confident discrimination of bacteria at the species, subspecies, and strain levels. High correlation coefficients were achieved between replicates. A sub-selection of 12,071 probes, determined by ANOVA and class prediction analysis, enabled the discrimination of all samples in our panel. Mismatch probe hybridisation was observed but was found to have no effect on the discriminatory capacity of our system. Conclusions These results indicate the potential of our genome chip for reliable identification of a wide range of bacterial taxa at the subspecies level without laborious prior sequencing and probe design. With its high resolution capacity, our proof-of-principle chip demonstrates great potential as a tool for molecular diagnostics of broad taxonomic groups.

  2. Against a Broad Definition of "Empathy"

    Directory of Open Access Journals (Sweden)

    Sarah Songhorian

    2015-04-01

    Full Text Available In this paper I will try to provide some arguments against a broad definition of “empathy”. Firstly, I will deal with attempts to define empathy as an umbrella concept. Then, I will try to point out the four main elements which contribute to the confusion that researchers in both the social and political as well as the scientific and philosophical domains face when dealing with empathy. In order to resolve this confusion, I suggest applying David Marr’s distinction to the field of empathy. Instead of providing an umbrella definition for empathy, which tries to account for all the data coming from different disciplines, I believe understanding that there are different levels of explanations and that different disciplines can contribute to each of them will provide a more detailed and less confused definition of empathy.

  3. Broad-band acoustic hyperbolic metamaterial

    CERN Document Server

    Shen, Chen; Sui, Ni; Wang, Wenqi; Cummer, Steven A; Jing, Yun

    2015-01-01

    Acoustic metamaterials (AMMs) are engineered materials, made from subwavelength structures, that exhibit useful or unusual constitutive properties. There has been intense research interest in AMMs since its first realization in 2000 by Liu et al. A number of functionalities and applications have been proposed and achieved using AMMs. Hyperbolic metamaterials are one of the most important types of metamaterials due to their extreme anisotropy and numerous possible applications, including negative refraction, backward waves, spatial filtering, and subwavelength imaging. Although the importance of acoustic hyperbolic metamaterials (AHMMs) as a tool for achieving full control of acoustic waves is substantial, the realization of a broad-band and truly hyperbolic AMM has not been reported so far. Here, we demonstrate the design and experimental characterization of a broadband AHMM that operates between 1.0 kHz and 2.5 kHz.

  4. A broad view of model validation

    International Nuclear Information System (INIS)

    The safety assessment of a nuclear waste repository requires the use of models. Such models need to be validated to ensure, as much as possible, that they are a good representation of the actual processes occurring in the real system. In this paper we attempt to take a broad view by reviewing step by step the modeling process and bringing out the need to validating every step of this process. This model validation includes not only comparison of modeling results with data from selected experiments, but also evaluation of procedures for the construction of conceptual models and calculational models as well as methodologies for studying data and parameter correlation. The need for advancing basic scientific knowledge in related fields, for multiple assessment groups, and for presenting our modeling efforts in open literature to public scrutiny is also emphasized. 16 refs

  5. Magnetohydrodynamic stability of broad line region clouds

    CERN Document Server

    Krause, Martin; Burkert, Andreas

    2012-01-01

    Hydrodynamic stability has been a longstanding issue for the cloud model of the broad line region in active galactic nuclei. We argue that the clouds may be gravitationally bound to the supermassive black hole. If true, stabilisation by thermal pressure alone becomes even more difficult. We further argue that if magnetic fields should be present in such clouds at a level that could affect the stability properties, they need to be strong enough to compete with the radiation pressure on the cloud. This would imply magnetic field values of a few Gauss for a sample of Active Galactic Nuclei we draw from the literature. We then investigate the effect of several magnetic configurations on cloud stability in axi-symmetric magnetohydrodynamic simulations. For a purely azimuthal magnetic field which provides the dominant pressure support, the cloud first gets compressed by the opposing radiative and gravitational forces. The pressure inside the cloud then increases, and it expands vertically. Kelvin-Helmholtz and colu...

  6. SPECTROSCOPY OF BROAD-LINE BLAZARS FROM 1LAC

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Michael S.; Romani, Roger W.; Healey, Stephen E.; Michelson, Peter F. [Department of Physics/KIPAC, Stanford University, Stanford, CA 94305 (United States); Cotter, Garret; Potter, William J. [Department of Astrophysics, University of Oxford, Oxford OX1 3RH (United Kingdom); Readhead, Anthony C. S.; Richards, Joseph L.; Max-Moerbeck, Walter; King, Oliver G. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

    2012-03-20

    We report on optical spectroscopy of 165 flat spectrum radio quasars (FSRQs) in the Fermi 1LAC sample, which have helped allow a nearly complete study of this population. Fermi FSRQs show significant evidence for non-thermal emission even in the optical; the degree depends on the {gamma}-ray hardness. They also have smaller virial estimates of hole mass than the optical quasar sample. This appears to be largely due to a preferred (axial) view of the {gamma}-ray FSRQ and non-isotropic (H/R {approx} 0.4) distribution of broad-line velocities. Even after correction for this bias, the Fermi FSRQs show higher mean Eddington ratios than the optical population. A comparison of optical spectral properties with Owens Valley Radio Observatory radio flare activity shows no strong correlation.

  7. A multi-colour study of the dark GRB 000210 host galaxy and its environment

    DEFF Research Database (Denmark)

    Gorosabel, J.; Christensen, Lise; Hjorth, J.;

    2003-01-01

    We present UBVRIZJsHKs broad band photometry of the host galaxy of the dark gamma-ray burst (GRB) of February 10, 2000. These observations represent the most exhaustive photometry given to date of any GRB host galaxy. A grid of spectral templates have been fitted to the Spectral Energy Distributi...

  8. Volatile fragrances associated with flowers mediate the host plant alternation of a polyphagous mirid bug

    Science.gov (United States)

    Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is an important insect pest of cotton, fruit trees and other crops in China, and exhibits a particularly broad host range. Adult A. lucorum greatly prefers host plants at the flowering stage, and their populations track flowering plants both spatiall...

  9. Correlated Resource Models of Internet End Hosts

    CERN Document Server

    Heien, Eric M; David, Anderson

    2010-01-01

    Understanding and modelling resources of Internet end hosts is essential for the design of desktop software and Internet-distributed applications. In this paper we develop a correlated resource model of Internet end hosts based on real trace data taken from the SETI@home project. This data covers a 5-year period with statistics for 2.7 million hosts. The resource model is based on statistical analysis of host computational power, memory, and storage as well as how these resources change over time and the correlations between them. We find that resources with few discrete values (core count, memory) are well modeled by exponential laws governing the change of relative resource quantities over time. Resources with a continuous range of values are well modeled with either correlated normal distributions (processor speed for integer operations and floating point operations) or log-normal distributions (available disk space). We validate and show the utility of the models by applying them to a resource allocation ...

  10. The artist as host

    NARCIS (Netherlands)

    Coumans, Anke; Maat, Hermen; Lancel, Karen

    2013-01-01

    In this publication you will find: Hosting the hybrid city This is a text in which Hermen Maat and Karen Lancel provide insights into the meaning of the word ‘role’ and into the position of the role of the ‘host’ in their own artistic practice. Their artistic research into this role was the starting

  11. Patterns of co-speciation and host switching in primate malaria parasites

    OpenAIRE

    Garamszegi László

    2009-01-01

    Abstract Background The evolutionary history of many parasites is dependent on the evolution of their hosts, leading to an association between host and parasite phylogenies. However, frequent host switches across broad phylogenetic distances may weaken this close evolutionary link, especially when vectors are involved in parasites transmission, as is the case for malaria pathogens. Several studies suggested that the evolution of the primate-infective malaria lineages may be constrained by the...

  12. φX216, a P2-like bacteriophage with broad Burkholderia pseudomallei and B. mallei strain infectivity

    Directory of Open Access Journals (Sweden)

    Kvitko Brian H

    2012-12-01

    Full Text Available Abstract Background Burkholderia pseudomallei and B. mallei are closely related Category B Select Agents of bioterrorism and the causative agents of the diseases melioidosis and glanders, respectively. Rapid phage-based diagnostic tools would greatly benefit early recognition and treatment of these diseases. There is extensive strain-to-strain variation in B. pseudomallei genome content due in part to the presence or absence of integrated prophages. Several phages have previously been isolated from B. pseudomallei lysogens, for example φK96243, φ1026b and φ52237. Results We have isolated a P2-like bacteriophage, φX216, which infects 78% of all B. pseudomallei strains tested. φX216 also infects B. mallei, but not other Burkholderia species, including the closely related B. thailandensis and B. oklahomensis. The nature of the φX216 host receptor remains unclear but evidence indicates that in B. mallei φX216 uses lipopolysaccharide O-antigen but a different receptor in B. pseudomallei. The 37,637 bp genome of φX216 encodes 47 predicted open reading frames and shares 99.8% pairwise identity and an identical strain host range with bacteriophage φ52237. Closely related P2-like prophages appear to be widely distributed among B. pseudomallei strains but both φX216 and φ52237 readily infect prophage carrying strains. Conclusions The broad strain infectivity and high specificity for B. pseudomallei and B. mallei indicate that φX216 will provide a good platform for the development of phage-based diagnostics for these bacteria.

  13. Predation determines different selective pressure on pea aphid host races in a complex agricultural mosaic.

    Directory of Open Access Journals (Sweden)

    Adalbert Balog

    Full Text Available Field assessments were conducted to examine the interplay between host plant and predation in complex agricultural mosaic on pea aphid clover and alfalfa races. In one experiment, we examined the relative fitness on clover race (CR and alfalfa race (AR pea aphids on broad bean, red clover and alfalfa alone. But because clover is typically grown in a more complex agricultural mosaic with alfalfa and broad bean, a second experiment was conducted to assess the fitness consequences under predation in a more complex agricultural field setting that also included potential apparent competition with AR pea aphids. In a third experiment we tested for the effect of differential host race density on the fitness of the other host race mediated by a predator effect. CR pea aphids always had fitness losses when on broad bean (had lower fitness on broad bean relative to red clover and fitness benefits when on red clover (higher fitness on red clover relative to broad bean, whether or not in apparent competition with alfalfa race aphids on bean and alfalfa. AR suffered fitness loss on both alfalfa and bean in apparent competition with CR on clover. Therefore we can conclude that the predation rate between host races was highly asymmetrical. The complexity of the agricultural mosaic thus can influence prey selection by predators on different host plants. These may have evolutionary consequences through context dependent fitness benefits on particular host plants.

  14. Silver Nanoparticles: Biosynthesis Using an ATCC Reference Strain of Pseudomonas aeruginosa and Activity as Broad Spectrum Clinical Antibacterial Agents

    Science.gov (United States)

    Quinteros, Melisa A.; Aiassa Martínez, Ivana M.; Dalmasso, Pablo R.; Páez, Paulina L.

    2016-01-01

    Currently, the biosynthesis of silver-based nanomaterials attracts enormous attention owing to the documented antimicrobial properties of these ones. This study reports the extracellular biosynthesis of silver nanoparticles (Ag-NPs) using a Pseudomonas aeruginosa strain from a reference culture collection. A greenish culture supernatant of P. aeruginosa incubated at 37°C with a silver nitrate solution for 24 h changed to a yellowish brown color, indicating the formation of Ag-NPs, which was confirmed by UV-vis spectroscopy, transmission electron microscopy, and X-ray diffraction. TEM analysis showed spherical and pseudospherical nanoparticles with a distributed size mainly between 25 and 45 nm, and the XRD pattern revealed the crystalline nature of Ag-NPs. Also it provides an evaluation of the antimicrobial activity of the biosynthesized Ag-NPs against human pathogenic and opportunistic microorganisms, namely, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Proteus mirabilis, Acinetobacter baumannii, Escherichia coli, P. aeruginosa, and Klebsiella pneumonia. Ag-NPs were found to be bioactive at picomolar concentration levels showing bactericidal effects against both Gram-positive and Gram-negative bacterial strains. This work demonstrates the first helpful use of biosynthesized Ag-NPs as broad spectrum bactericidal agents for clinical strains of pathogenic multidrug-resistant bacteria such as methicillin-resistant S. aureus, A. baumannii, and E. coli. In addition, these Ag-NPs showed negligible cytotoxic effect in human neutrophils suggesting low toxicity to the host. PMID:27340405

  15. Niclosamide is a proton carrier and targets acidic endosomes with broad antiviral effects.

    Directory of Open Access Journals (Sweden)

    Andreas Jurgeit

    Full Text Available Viruses use a limited set of host pathways for infection. These pathways represent bona fide antiviral targets with low likelihood of viral resistance. We identified the salicylanilide niclosamide as a broad range antiviral agent targeting acidified endosomes. Niclosamide is approved for human use against helminthic infections, and has anti-neoplastic and antiviral effects. Its mode of action is unknown. Here, we show that niclosamide, which is a weak lipophilic acid inhibited infection with pH-dependent human rhinoviruses (HRV and influenza virus. Structure-activity studies showed that antiviral efficacy and endolysosomal pH neutralization co-tracked, and acidification of the extracellular medium bypassed the virus entry block. Niclosamide did not affect the vacuolar H(+-ATPase, but neutralized coated vesicles or synthetic liposomes, indicating a proton carrier mode-of-action independent of any protein target. This report demonstrates that physico-chemical interference with host pathways has broad range antiviral effects, and provides a proof of concept for the development of host-directed antivirals.

  16. The evolution of host specialisation in avian brood parasites.

    Science.gov (United States)

    Medina, Iliana; Langmore, Naomi E

    2016-09-01

    Traditional ecological theory predicts that specialisation can promote speciation; hence, recently derived species are specialists. However, an alternative view is that new species have broad niches, which become narrower and specialised over time. Here, we test these hypotheses using avian brood parasites and three different measures of host specialisation. Brood parasites provide an ideal system in which to investigate the evolution of specialisation, because some exploit more than 40 host species and others specialise on only one. We find that young brood parasite species are smaller and specialise on a narrower range of host sizes, as expected, if specialisation is linked with the generation of new species. Moreover, we show that highly virulent parasites are more specialised, supporting findings in other host-parasite systems. Finally, we demonstrate that different measures of specialisation can lead to different conclusions, and specialisation indices should be designed taking into account the biology of each system. PMID:27417381

  17. Host, habitat and climate preferences of Ixodes angustus (Acari: Ixodidae) and infection with Borrelia burgdorferi and Anaplasma phagocytophilum in California, USA.

    Science.gov (United States)

    Stephenson, Nicole; Wong, Johnny; Foley, Janet

    2016-10-01

    The Holarctic tick Ixodes angustus is a competent vector for Borrelia burgdorferi, the etiologic agent of Lyme disease, and possibly Anaplasma phagocytophilum, the etiologic agent of granulocytic anaplasmosis, as well. From 2005 to 2013, we collected host-feeding I. angustus individuals from live-trapped small mammals and by flagging vegetation from 12 study sites in northern and central California, and tested for B. burgdorferi sensu lato, A. phagocytophilum, and Rickettsia spp. DNA by real-time PCR. Among 261 I. angustus collected (259 from hosts and two by flagging), the most common hosts were tree squirrels (20 % of ticks) and chipmunks (37 %). The PCR-prevalence for A. phagocytophilum and B. burgdorferi in ticks was 2 % and zero, respectively. The minimum infection prevalence on pooled DNA samples was 10 % for Rickettsia spp. DNA sequencing of the ompA gene identified this rickettsia as Candidatus Rickettsia angustus, a putative endosymbiont. A zero-inflated negative binomial mixed effects model was used to evaluate geographical and climatological predictors of I. angustus burden. When host species within study site and season within year were included in the model as nested random effects, all significant variables revealed that I. angustus burden increased as temperature decreased. Together with published data, these findings suggest that I. angustus is a host generalist, has a broad geographic distribution, is more abundant in areas with lower temperature within it's range, and is rarely infected with the pathogens A. phagocytophilum and B. burgdorferi.

  18. High Metallicity LGRB Hosts

    CERN Document Server

    Graham, J F; Levesque, E M; Kewley, L J; Tanvir, N R; Levan, A J; Patel, S K; Misra, K; Huang, K -H; Reichart, D E; Nysewander, M; Schady, P

    2015-01-01

    We present our imaging and spectroscopic observations of the host galaxies of two dark long bursts with anomalously high metallicities, LGRB 051022 and LGRB 020819B, which in conjunction with another LGRB event with an optical afterglow comprise the three LGRBs with high metallicity host galaxies in the Graham & Fruchter (2013) sample. In Graham & Fruchter (2013), we showed that LGRBs exhibit a strong and apparently intrinsic preference for low metallicity environments (12+log(O/H) < 8.4 in the KK04 scale) in spite of these three cases with abundances of about solar and above. These exceptions however are consistent with the general star-forming galaxy population of comparable brightness & redshift. This is surprising: even among a preselected sample of high metallicity LGRBs, were the metal aversion to remain in effect for these objects, we would expect their metallicity to still be lower than the typical metallicity for the galaxies at that luminosity and redshift. Therefore we deduce that it...

  19. Characterization of exoplanet hosts

    Directory of Open Access Journals (Sweden)

    Valenti Jeff A.

    2013-04-01

    Full Text Available Spectroscopic analysis of exoplanet hosts and the stellar sample from which they are drawn provides abundances and other properties that quantitively constrain models of planet formation. The program Spectroscopy Made Easy (SME determines stellar parameters by fitting observed spectra, though line lists must be selected wisely. For giant planets, it is now well established that stars with higher metallicity are more likely to have detected companions. Stellar metallicity does not seem to affect the formation and/or migration of detectable planets less massive than Neptune, especially when considering only the most massive planet in the system. In systems with at least one planet less than 10 times the mass of Earth, the mass of the most massive planet increases dramatically with host star metallicity. This may reflect metallicity dependent timescales for core formation, envelope accretion, and/or migration into the detection zone.

  20. A robot to detect and control broad-leaved dock (Rumex obtusifolius L.) in grassland

    NARCIS (Netherlands)

    Evert, van F.K.; Samsom, J.; Polder, G.; Vijn, M.P.; Dooren, van H.J.C.; Lamaker, E.J.J.; Heijden, van der G.W.A.M.; Kempenaar, C.; Zalm, van der A.J.A.; Lotz, L.A.P.

    2011-01-01

    Broad-leaved dock is a common and troublesome grassland weed with a wide geographic distribution. In conventional farming the weed is normally controlled by using a selective herbicide, but in organic farming manual removal is the best option to control this weed. The objective of our work was to de

  1. Broad spectrum anthelmintic potential of Cassia plants

    Institute of Scientific and Technical Information of China (English)

    Suman Kundu; Saptarshi Roy; Larisha Mawkhleing Lyndem

    2014-01-01

    Objective: To study the in vitro anthelmintic efficacy of Cassia alata (C. alata), Cassia(C. angustifolia) and Cassia occidentalis (C. occidentalis). angustifolia Methods: Crude ethanol extract from leaves of the three plants were prepared in rotary evaporator and different concentrations (10, 20 and 40 mg/mL) of leaf extracts were used for treatment on different representatives of helminthes (Heterakis gallinarum, Raillietina tetragona and Catatropis sp.) from domestic fowl (Gallus gallus domesticus). Loss of motility and death were monitored frequently.Results: C. alata showed early paralysis in all worms treated followed by C. angustifolia. C. occidentalis in combination with C. alata together caused early paralysis in all treated worms than the combination of C. alata with C. angustfolia. While Heterakis gallinarum in control survived for (81.33±2.07) h, treated worms lost their motility at (5.71±0.10) h, (6.60±0.86) h and (13.95±0.43) h with C. angustifolia, C. alata and C. occidentalis respectively at a concentration of 40 mg/mL which showed better efficacy than albendazole. Catatropis sp. survival period was (26.49±1.38) h in control, but with plant treatment, it lost its motility in just (0.57±0.08) h, (1.00±0.12) h and (1.47±0.40) h at 40 mg/mL concentration of C. alata, C. angustifolia and C. occidentalis respectively.Raillietina tetragona on the other hand became paralysed at (1.68±0.27) h, (2.95±0.29) h and (4.13±0.31) h with above concentrations treated with three plants respectively, however in control it survived up to (81.93±4.71) h.Conclusions:This present study indicated broad spectrum vermifugal activity of all plants tested.

  2. Hosting a Katrina Evacuee.

    Science.gov (United States)

    Hoagland, David

    2008-03-01

    No individual or institution anticipated the impact on the academic research community of hurricane Katrina. When Tulane physicist Wayne Reed asked me to host his research group just a day or two after the disaster, with no authorization or understanding of the commitment, I agreed immediately and then pondered implications. Fortunately, colleagues helped in making the commitment real, only the bureaucracy of my public university posing small hindrances. Industry was remarkably generous in providing Reed with significant ``loaner'' equipment, and amazingly, a suite of custom Reed experiments was running within weeks. At the end, the most productive collaborations for Reed seemed not to have been with my group, with its similar research, but to other groups at my institution, particularly the synthetic chemists, who gained access to methods previously unique to Tulane while offering samples previously unique to UMass. Quickly designed projects exploiting this match turned out remarkably productive. Although begun with trepidation, hosting of Reed had huge positive benefits to me and UMass, and I believe, also to Reed and Tulane. Some key lessons for the future: (i) industry has capacity and willingness to help academic research during disruption (ii) commitment of a host institution must be immediate, without a wait for formal approvals or arrangement of special funding -- delay leads only to discouragement, (iii) continuing academic progress of displaced students must come first, and (iv) intellectual synergy rather than overlap should be the basis for seeking a host. Lastly, NSF or other funding agency should consider a program directly addressing the research needs of unexpectedly disrupted academic scientists, and most particularly, graduate students who face greatly extended studies.

  3. Validation, automatic generation and use of broad phonetic transcriptions

    NARCIS (Netherlands)

    Bael, Cristophe Patrick Jan Van

    2007-01-01

    Broad phonetic transcriptions represent the pronunciation of words as strings of characters from specifically designed symbol sets. In everyday life, broad phonetic transcriptions are often used as aids to pronounce (foreign) words. In addition, broad phonetic transcriptions are often used for lingu

  4. Broad-Spectrum Solution-Processed Photovoltaics

    Science.gov (United States)

    Ip, Alexander Halley

    High global demand for energy coupled with dwindling fossil fuel supply has driven the development of sustainable energy sources such as solar photovoltaics. Emerging solar technologies aim for low-cost, solution-processable materials which would allow wide deployment. Colloidal quantum dots (CQDs) are such a materials system which exhibits the ability to absorb across the entire solar spectrum, including in the infrared where many technologies cannot harvest photons. However, due to their nanocrystalline nature, CQDs are susceptible to surface-associated electronic traps which greatly inhibit performance. In this thesis, surface engineering of CQDs is presented through a combined ligand approach which improves the passivation of surface trap states. A metal halide treatment is found to passivate quantum dot surfaces in solution, while bifunctional organic ligands produce a dense film in solid state. This approach reduced midgap trap states fivefold compared with conventional passivation strategies and led to solar cells with a record certified 7.0% power conversion efficiency. The effect of this process on the electronic structure is studied through photoelectron spectroscopy. It is found that while the halide provides deep trap passivation, the nature of the metal cation on the CQD surface affects the density of band tail states. This effect is explored further through a wide survey of materials, and it is found that the coordination ability of the metal cation is responsible for the suppression of shallow traps. With this understanding of CQD surface passivation, broad spectral usage is then explored through a study of visible-absorbing organolead halide perovskite materials as well as narrow-bandgap CQD solar cells. Control over growth conditions and modification of electrode interfaces resulted in efficient perovskite devices with effective usages of visible photons. For infrared-absorbing CQDs, it is found that, in addition to providing surface trap

  5. Isolation of Polyvalent Bacteriophages by Sequential Multiple-Host Approaches.

    Science.gov (United States)

    Yu, Pingfeng; Mathieu, Jacques; Li, Mengyan; Dai, Zhaoyi; Alvarez, Pedro J J

    2015-11-20

    Many studies on phage biology are based on isolation methods that may inadvertently select for narrow-host-range phages. Consequently, broad-host-range phages, whose ecological significance is largely unexplored, are consistently overlooked. To enhance research on such polyvalent phages, we developed two sequential multihost isolation methods and tested both culture-dependent and culture-independent phage libraries for broad infectivity. Lytic phages isolated from activated sludge were capable of interspecies or even interorder infectivity without a significant reduction in the efficiency of plating (0.45 to 1.15). Two polyvalent phages (PX1 of the Podoviridae family and PEf1 of the Siphoviridae family) were characterized in terms of adsorption rate (3.54 × 10(-10) to 8.53 × 10(-10) ml/min), latent time (40 to 55 min), and burst size (45 to 99 PFU/cell), using different hosts. These phages were enriched with a nonpathogenic host (Pseudomonas putida F1 or Escherichia coli K-12) and subsequently used to infect model problematic bacteria. By using a multiplicity of infection of 10 in bacterial challenge tests, >60% lethality was observed for Pseudomonas aeruginosa relative to uninfected controls. The corresponding lethality for Pseudomonas syringae was ∼ 50%. Overall, this work suggests that polyvalent phages may be readily isolated from the environment by using different sequential hosts, and this approach should facilitate the study of their ecological significance as well as enable novel applications.

  6. Understanding heliothine (Lepidoptera: Heliothinae) pests: what is a host plant?

    Science.gov (United States)

    Cunningham, John Paul; Zalucki, Myron P

    2014-06-01

    Heliothine moths (Lepidoptera: Heliothinae) include some of the world's most devastating pest species. Whereas the majority of nonpest heliothinae specialize on a single plant family, genus, or species, pest species are highly polyphagous, with populations often escalating in size as they move from one crop species to another. Here, we examine the current literature on heliothine host-selection behavior with the aim of providing a knowledge base for research scientists and pest managers. We review the host relations of pest heliothines, with a particular focus on Helicoverpa armigera (Hübner), the most economically damaging of all heliothine species. We then consider the important question of what constitutes a host plant in these moths, and some of the problems that arise when trying to determine host plant status from empirical studies on host use. The top six host plant families in the two main Australian pest species (H. armigera and Helicoverpa punctigera Wallengren) are the same and the top three (Asteraceae, Fabaceae, and Malvaceae) are ranked the same (in terms of the number of host species on which eggs or larvae have been identified), suggesting that these species may use similar cues to identify their hosts. In contrast, for the two key pest heliothines in the Americas, the Fabaceae contains approximately 1/3 of hosts for both. For Helicoverpa zea (Boddie), the remaining hosts are more evenly distributed, with Solanaceae next, followed by Poaceae, Asteraceae, Malvaceae, and Rosaceae. For Heliothis virescens (F.), the next highest five families are Malvaceae, Asteraceae, Solanaceae, Convolvulaceae, and Scrophulariaceae. Again there is considerable overlap in host use at generic and even species level. H. armigera is the most widely distributed and recorded from 68 plant families worldwide, but only 14 families are recorded as a containing a host in all geographic areas. A few crop hosts are used throughout the range as expected, but in some cases there

  7. Inhibition of host extracellular signal-regulated kinase (ERK) activation decreases new world alphavirus multiplication in infected cells

    Energy Technology Data Exchange (ETDEWEB)

    Voss, Kelsey; Amaya, Moushimi [National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, 10650 Pyramid Place, Manassas, VA (United States); Mueller, Claudius [Center for Applied Proteomics and Personalized Medicine, George Mason University, 10900 University Boulevard, Manassas, VA (United States); Roberts, Brian [Leidos Health Life Sciences, 5202 Presidents Court, Suite 110, Frederick, MD (United States); Kehn-Hall, Kylene; Bailey, Charles [National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, 10650 Pyramid Place, Manassas, VA (United States); Petricoin, Emanuel [Center for Applied Proteomics and Personalized Medicine, George Mason University, 10900 University Boulevard, Manassas, VA (United States); Narayanan, Aarthi, E-mail: anaraya1@gmu.edu [National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, 10650 Pyramid Place, Manassas, VA (United States)

    2014-11-15

    New World alphaviruses belonging to the family Togaviridae are classified as emerging infectious agents and Category B select agents. Our study is focused on the role of the host extracellular signal-regulated kinase (ERK) in the infectious process of New World alphaviruses. Infection of human cells by Venezuelan equine encephalitis virus (VEEV) results in the activation of the ERK-signaling cascade. Inhibition of ERK1/2 by the small molecule inhibitor Ag-126 results in inhibition of viral multiplication. Ag-126-mediated inhibition of VEEV was due to potential effects on early and late stages of the infectious process. While expression of viral proteins was down-regulated in Ag-126 treated cells, we did not observe any influence of Ag-126 on the nuclear distribution of capsid. Finally, Ag-126 exerted a broad-spectrum inhibitory effect on New World alphavirus multiplication, thus indicating that the host kinase, ERK, is a broad-spectrum candidate for development of novel therapeutics against New World alphaviruses. - Highlights: • VEEV infection activated multiple components of the ERK signaling cascade. • Inhibition of ERK activation using Ag-126 inhibited VEEV multiplication. • Activation of ERK by Ceramide C6 increased infectious titers of TC-83. • Ag-126 inhibited virulent strains of all New World alphaviruses. • Ag-126 treatment increased percent survival of infected cells.

  8. The path to host extinction can lead to loss of generalist parasites.

    Science.gov (United States)

    Farrell, Maxwell J; Stephens, Patrick R; Berrang-Ford, Lea; Gittleman, John L; Davies, T Jonathan

    2015-07-01

    Host extinction can alter disease transmission dynamics, influence parasite extinction and ultimately change the nature of host-parasite systems. While theory predicts that single-host parasites are among the parasite species most susceptible to extinction following declines in their hosts, documented parasite extinctions are rare. Using a comparative approach, we investigate how the richness of single-host and multi-host parasites is influenced by extinction risk among ungulate and carnivore hosts. Host-parasite associations for free-living carnivores (order Carnivora) and terrestrial ungulates (orders Perissodactyla + Cetartiodactyla minus cetaceans) were merged with host trait data and IUCN Red List status to explore the distribution of single-host and multi-host parasites among threatened and non-threatened hosts. We find that threatened ungulates harbour a higher proportion of single-host parasites compared to non-threatened ungulates, which is explained by decreases in the richness of multi-host parasites. However, among carnivores threat status is not a significant predictor of the proportion of single-host parasites, or the richness of single-host or multi-host parasites. The loss of multi-host parasites from threatened ungulates may be explained by decreased cross-species contact as hosts decline and habitats become fragmented. Among carnivores, threat status may not be important in predicting patterns of parasite specificity because host decline results in equal losses of both single-host parasites and multi-host parasites through reduction in average population density and frequency of cross-species contact. Our results contrast with current models of parasite coextinction and highlight the need for updated theories that are applicable across host groups and account for both inter- and intraspecific contact.

  9. Squalamine as a broad-spectrum systemic antiviral agent with therapeutic potential.

    Science.gov (United States)

    Zasloff, Michael; Adams, A Paige; Beckerman, Bernard; Campbell, Ann; Han, Ziying; Luijten, Erik; Meza, Isaura; Julander, Justin; Mishra, Abhijit; Qu, Wei; Taylor, John M; Weaver, Scott C; Wong, Gerard C L

    2011-09-20

    Antiviral compounds that increase the resistance of host tissues represent an attractive class of therapeutic. Here, we show that squalamine, a compound previously isolated from the tissues of the dogfish shark (Squalus acanthias) and the sea lamprey (Petromyzon marinus), exhibits broad-spectrum antiviral activity against human pathogens, which were studied in vitro as well as in vivo. Both RNA- and DNA-enveloped viruses are shown to be susceptible. The proposed mechanism involves the capacity of squalamine, a cationic amphipathic sterol, to neutralize the negative electrostatic surface charge of intracellular membranes in a way that renders the cell less effective in supporting viral replication. Because squalamine can be readily synthesized and has a known safety profile in man, we believe its potential as a broad-spectrum human antiviral agent should be explored. PMID:21930925

  10. Evidence for two spatially separated UV continuum emitting regions in the Cloverleaf broad absorption line quasar

    CERN Document Server

    Sluse, D; Anguita, T; Braibant, L; Riaud, P

    2015-01-01

    Testing the standard Shakura-Sunyaev model of accretion is a challenging task because the central region of quasars where accretion takes place is unresolved with telescopes. The analysis of microlensing in gravitationally lensed quasars is one of the few techniques which can test this model, yielding to the measurement of the size and of the temperature profile of the accretion disc. We present spectroscopic observations of the gravitationally lensed broad absorption line quasar H1413+117, which reveal partial microlensing of the continuum emission that appears to originate from two separated regions, a microlensed region corresponding the compact accretion disc, and a non-microlensed region, more extended and contributing to at least 30\\% of the total UV-continuum flux. Because this extended continuum is occulted by the broad absorption line clouds, it is not associated to the host galaxy, but rather to light scattered in the neighbourhood of the central engine. We measure the amplitude of microlensing of t...

  11. Prevalence, mean intensity of infestation and host specificity of Spinturnicidae mites (Acari: Mesostigmata) on bats (Mammalia: Chiroptera) in the Pantanal, Brazil.

    Science.gov (United States)

    Silva, Camila de Lima; Graciolli, Gustavo

    2013-06-01

    Acari ectoparasites were collected from bats during 12 months in the Rio Negro farm (19°34'22″S and 56°14'36″W), Aquidauana, Mato Grosso do Sul. A total of 654 bats belonging to the families Phyllostomidae, Noctilionidae, Molossidae, Vespertilionidae and Emballonuridae were captured. Only 136 bats of nine genera and 11 species were parasitised. Periglischrus iheringi Oudemans was the most abundant mite species, and this prevalence may be related to the low degree of host specificity of this species and due to the broad geographical distribution of its hosts. The greatest mean intensity was found to Periglischrus torrealbai Machado-Allison on Phyllostomus discolor Wagner (Phyllostomidae) and Periglischrus tonatii Herrin and Tipton associated with Lophostoma silviculum d'Orbigny (Phyllostomidae), which also had the highest prevalence of infestation.

  12. The Sloan Digital Sky Survey Reverberation Mapping Project: Rapid CIV Broad Absorption Line Variability

    Science.gov (United States)

    Grier, C. J.; Hall, P. B.; Brandt, W. N.; Trump, J. R.; Shen, Yue; Vivek, M.; Filiz Ak, N.; Chen, Yuguang; Dawson, K. S.; Denney, K. D.; Green, Paul J.; Jiang, Linhua; Kochanek, C. S.; McGreer, Ian D.; Pâris, I.; Peterson, B. M.; Schneider, D. P.; Tao, Charling; Wood-Vasey, W. M.; Bizyaev, Dmitry; Ge, Jian; Kinemuchi, Karen; Oravetz, Daniel; Pan, Kaike; Simmons, Audrey

    2015-06-01

    We report the discovery of rapid variations of a high-velocity C iv broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation Mapping Project, during which 32 epochs of spectroscopy were obtained with the Baryon Oscillation Spectroscopic Survey spectrograph. We observe significant (>4σ) variability in the equivalent width (EW) of the broad (˜4000 km s-1 wide) C iv trough on rest-frame timescales as short as 1.20 days (˜29 hr), the shortest broad absorption line variability timescale yet reported. The EW varied by ˜10% on these short timescales, and by about a factor of two over the duration of the campaign. We evaluate several potential causes of the variability, concluding that the most likely cause is a rapid response to changes in the incident ionizing continuum. If the outflow is at a radius where the recombination rate is higher than the ionization rate, the timescale of variability places a lower limit on the density of the absorbing gas of ne ≳ 3.9 × 105 cm-3. The broad absorption line variability characteristics of this quasar are consistent with those observed in previous studies of quasars, indicating that such short-term variability may in fact be common and thus can be used to learn about outflow characteristics and contributions to quasar/host-galaxy feedback scenarios.

  13. BROAD Hβ EMISSION-LINE VARIABILITY IN A SAMPLE OF 102 LOCAL ACTIVE GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Runco, Jordan N.; Cosens, Maren; Bennert, Vardha N.; Scott, Bryan [Physics Department, California Polytechnic State University, San Luis Obispo CA 93407 (United States); Komossa, S. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121, Bonn (Germany); Malkan, Matthew A.; Treu, Tommaso [Department of Physics, University of California, Los Angeles, CA 90095 (United States); Lazarova, Mariana S. [Department of Physics and Physical Science, University of Nebraska Kearney, Kearney, NE 68849 (United States); Auger, Matthew W. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Park, Daeseong, E-mail: jrunco@calpoly.edu, E-mail: mcosens@calpoly.edu, E-mail: vbennert@calpoly.edu, E-mail: malkan@astro.ucla.edu, E-mail: tt@physics.ucsb.edu, E-mail: lazarovam2@unk.edu, E-mail: mauger@ast.cam.ac.uk, E-mail: daeseongpark@kasi.re.kr [Korea Astronomy and Space Science Institute, Daejeon, 34055 (Korea, Republic of)

    2016-04-10

    A sample of 102 local (0.02 ≤ z ≤ 0.1) Seyfert galaxies with black hole masses M{sub BH} > 10{sup 7}M{sub ⊙} was selected from the Sloan Digital Sky Survey (SDSS) and observed using the Keck 10 m telescope to study the scaling relations between M{sub BH} and host galaxy properties. We study profile changes of the broad Hβ emission line within the three to nine year time frame between the two sets of spectra. The variability of the broad Hβ emission line is of particular interest, not only because it is used to estimate M{sub BH}, but also because its strength and width are used to classify Seyfert galaxies into different types. At least some form of broad-line variability (in either width or flux) is observed in the majority (∼66%) of the objects, resulting in a Seyfert-type change for ∼38% of the objects, likely driven by variable accretion and/or obscuration. The broad Hβ line virtually disappears in 3/102 (∼3%) extreme cases. We discuss potential causes for these changing look active galactic nuclei. While similar dramatic transitions have previously been reported in the literature, either on a case-by-case basis or in larger samples focusing on quasars at higher redshifts, our study provides statistical information on the frequency of Hβ line variability in a sample of low-redshift Seyfert galaxies.

  14. Broad Hbeta Emission-Line Variability in a Sample of 102 Local Active Galaxies

    CERN Document Server

    Runco, Jordan N; Bennert, Vardha N; Scott, Bryan; Komossa, S; Malkan, Matthew A; Lazarova, Mariana S; Auger, Matthew W; Treu, Tommaso; Park, Daeseong

    2016-01-01

    A sample of 102 local (0.02 10^7 M_sun was selected from the Sloan Digital Sky Survey (SDSS) and observed using the Keck 10-m telescope to study the scaling relations between MBH and host galaxy properties. We study profile changes of the broad Hbeta emission line within the ~3-9 year time-frame between the two sets of spectra. The variability of the broad Hbeta emission line is of particular interest, not only since it is used to estimate MBH, but also since its strength and width is used to classify Seyfert galaxies into different types. At least some form of broad-line variability (in either width or flux) is observed in the majority (~66%) of the objects, resulting in a Seyfert-type change for ~38% of the objects, likely driven by variable accretion and/or obscuration. The broad Hbeta line virtually disappears in 3/102 (~3%) extreme cases. We discuss potential causes for these changing-look AGNs. While similar dramatic transitions have previously been reported in the literature, either on a case-by-case ...

  15. What Can Phages Tell Us about Host-Pathogen Coevolution?

    Directory of Open Access Journals (Sweden)

    John J. Dennehy

    2012-01-01

    Full Text Available The outcomes of host-parasite interactions depend on the coevolutionary forces acting upon them, but because every host-parasite relation is enmeshed in a web of biotic and abiotic interactions across a heterogeneous landscape, host-parasite coevolution has proven difficult to study. Simple laboratory phage-bacteria microcosms can ameliorate this difficulty by allowing controlled, well-replicated experiments with a limited number of interactors. Genetic, population, and life history data obtained from these studies permit a closer examination of the fundamental correlates of host-parasite coevolution. In this paper, I describe the results of phage-bacteria coevolutionary studies and their implications for the study of host-parasite coevolution. Recent experimental studies have confirmed phage-host coevolutionary dynamics in the laboratory and have shown that coevolution can increase parasite virulence, specialization, adaptation, and diversity. Genetically, coevolution frequently proceeds in a manner best described by the Gene for Gene model, typified by arms race dynamics, but certain contexts can result in Red Queen dynamics according to the Matching Alleles model. Although some features appear to apply only to phage-bacteria systems, other results are broadly generalizable and apply to all instances of antagonistic coevolution. With laboratory host-parasite coevolutionary studies, we can better understand the perplexing array of interactions that characterize organismal diversity in the wild.

  16. TOUGH: Observational aspects of gamma-ray burst host galaxies

    CERN Document Server

    Hjorth, Jens; Jaunsen, Andreas O; Levan, Andrew J; Milvang-Jensen, Bo; Watson, Darach; Gorosabel, Javier; Fynbo, Johan P U; Michałowski, Michał J; Tanvir, Nial R; Jakobsson, Páll; Møller, Palle; Schulze, Steve; Krühler, Thomas

    2012-01-01

    GRB-selected galaxies are broadly known to be faint, blue, young, star-forming dwarf galaxies. This insight, however, is based in part on heterogeneous samples of optically selected, lower-redshift galaxies. To study the statistical properties of GRB-selected galaxies we here introduce The Optically Unbiased GRB Host (TOUGH) complete sample of 69 X-ray selected Swift GRB host galaxies spanning the redshift range 0.03-6.30 and summarise the first results of a large observational survey of these galaxies.

  17. Illuminating coronavirus-host interactions

    NARCIS (Netherlands)

    Raaben, M.

    2009-01-01

    Viruses are infectious agents incapable of growing or reproducing outside a host cell. They are completely dependent on the cellular machinery of the host for their multiplication. On the other hand, however, viruses also have to deal with the immune defences of the host. Apparently, viruses are wal

  18. Comparing mechanisms of host manipulation across host and parasite taxa

    Science.gov (United States)

    Lafferty, Kevin D.; Shaw, Jenny C.

    2013-01-01

    Parasites affect host behavior in several ways. They can alter activity, microhabitats or both. For trophically transmitted parasites (the focus of our study), decreased activity might impair the ability of hosts to respond to final-host predators, and increased activity and altered microhabitat choice might increase contact rates between hosts and final-host predators. In an analysis of trophically transmitted parasites, more parasite groups altered activity than altered microhabitat choice. Parasites that infected vertebrates were more likely to impair the host’s reaction to predators, whereas parasites that infected invertebrates were more likely to increase the host’s contact with predators. The site of infection might affect how parasites manipulate their hosts. For instance, parasites in the central nervous system seem particularly suited to manipulating host behavior. Manipulative parasites commonly occupy the body cavity, muscles and central nervous systems of their hosts. Acanthocephalans in the data set differed from other taxa in that they occurred exclusively in the body cavity of invertebrates. In addition, they were more likely to alter microhabitat choice than activity. Parasites in the body cavity (across parasite types) were more likely to be associated with increased host contact with predators. Parasites can manipulate the host through energetic drain, but most parasites use more sophisticated means. For instance, parasites target four physiological systems that shape behavior in both invertebrates and vertebrates: neural, endocrine, neuromodulatory and immunomodulatory. The interconnections between these systems make it difficult to isolate specific mechanisms of host behavioral manipulation.

  19. HostPhinder: A Phage Host Prediction Tool.

    Science.gov (United States)

    Villarroel, Julia; Kleinheinz, Kortine Annina; Jurtz, Vanessa Isabell; Zschach, Henrike; Lund, Ole; Nielsen, Morten; Larsen, Mette Voldby

    2016-01-01

    The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPhinder predicts the host species of a query phage as the host of the most genomically similar reference phages. As a measure of genomic similarity the number of co-occurring k-mers (DNA sequences of length k) is used. Using an independent evaluation set, HostPhinder was able to correctly predict host genus and species for 81% and 74% of the phages respectively, giving predictions for more phages than BLAST and significantly outperforming BLAST on phages for which both had predictions. HostPhinder predictions on phage draft genomes from the INTESTI phage cocktail corresponded well with the advertised targets of the cocktail. Our study indicates that for most phages genomic similarity correlates well with related bacterial hosts. HostPhinder is available as an interactive web service [1] and as a stand alone download from the Docker registry [2]. PMID:27153081

  20. HostPhinder: A Phage Host Prediction Tool

    Directory of Open Access Journals (Sweden)

    Julia Villarroel

    2016-05-01

    Full Text Available The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPhinder predicts the host species of a query phage as the host of the most genomically similar reference phages. As a measure of genomic similarity the number of co-occurring k-mers (DNA sequences of length k is used. Using an independent evaluation set, HostPhinder was able to correctly predict host genus and species for 81% and 74% of the phages respectively, giving predictions for more phages than BLAST and significantly outperforming BLAST on phages for which both had predictions. HostPhinder predictions on phage draft genomes from the INTESTI phage cocktail corresponded well with the advertised targets of the cocktail. Our study indicates that for most phages genomic similarity correlates well with related bacterial hosts. HostPhinder is available as an interactive web service [1] and as a stand alone download from the Docker registry [2].

  1. Broad-scale patterns of late jurassic dinosaur paleoecology.

    Directory of Open Access Journals (Sweden)

    Christopher R Noto

    Full Text Available BACKGROUND: There have been numerous studies on dinosaur biogeographic distribution patterns. However, these distribution data have not yet been applied to ecological questions. Ecological studies of dinosaurs have tended to focus on reconstructing individual taxa, usually through comparisons to modern analogs. Fewer studies have sought to determine if the ecological structure of fossil assemblages is preserved and, if so, how dinosaur communities varied. Climate is a major component driving differences between communities. If the ecological structure of a fossil locality is preserved, we expect that dinosaur assemblages from similar environments will share a similar ecological structure. METHODOLOGY/PRINCIPAL FINDINGS: This study applies Ecological Structure Analysis (ESA to a dataset of 100+ dinosaur taxa arranged into twelve composite fossil assemblages from around the world. Each assemblage was assigned a climate zone (biome based on its location. Dinosaur taxa were placed into ecomorphological categories. The proportion of each category creates an ecological profile for the assemblage, which were compared using cluster and principal components analyses. Assemblages grouped according to biome, with most coming from arid or semi-arid/seasonal climates. Differences between assemblages are tied to the proportion of large high-browsing vs. small ground-foraging herbivores, which separates arid from semi-arid and moister environments, respectively. However, the effects of historical, taphonomic, and other environmental factors are still evident. CONCLUSIONS/SIGNIFICANCE: This study is the first to show that the general ecological structure of Late Jurassic dinosaur assemblages is preserved at large scales and can be assessed quantitatively. Despite a broad similarity of climatic conditions, a degree of ecological variation is observed between assemblages, from arid to moist. Taxonomic differences between Asia and the other regions demonstrate at

  2. Reservoir host competence and the role of domestic and commensal hosts in the transmission of Trypanosoma cruzi.

    Science.gov (United States)

    Gürtler, Ricardo E; Cardinal, M V

    2015-11-01

    We review the epidemiological role of domestic and commensal hosts of Trypanosoma cruzi using a quantitative approach, and compiled >400 reports on their natural infection. We link the theory underlying simple mathematical models of vector-borne parasite transmission to the types of evidence used for reservoir host identification: mean duration of infectious life; host infection and infectiousness; and host-vector contact. The infectiousness of dogs or cats most frequently exceeded that of humans. The host-feeding patterns of major vectors showed wide variability among and within triatomine species related to their opportunistic behavior and variable ecological, biological and social contexts. The evidence shows that dogs, cats, commensal rodents and domesticated guinea pigs are able to maintain T. cruzi in the absence of any other host species. They play key roles as amplifying hosts and sources of T. cruzi in many (peri)domestic transmission cycles covering a broad diversity of ecoregions, ecotopes and triatomine species: no other domestic animal plays that role. Dogs comply with the desirable attributes of natural sentinels and sometimes were a point of entry of sylvatic parasite strains. The controversies on the role of cats and other hosts illustrate the issues that hamper assessing the relative importance of reservoir hosts on the basis of fragmentary evidence. We provide various study cases of how eco-epidemiological and genetic-marker evidence helped to unravel transmission cycles and identify the implicated hosts. Keeping dogs, cats and rodents out of human sleeping quarters and reducing their exposure to triatomine bugs are predicted to strongly reduce transmission risks. PMID:26051910

  3. Complete Genome Sequence of Xanthomonas citri subsp. citri Strain Aw12879, a Restricted-Host-Range Citrus Canker-Causing Bacterium

    OpenAIRE

    Jalan, Neha; Kumar, Dibyendu; Yu, Fahong; Jones, Jeffrey B; Graham, James H; Wang, Nian

    2013-01-01

    Xanthomonas citri subsp. citri causes citrus canker. The Asiatic strain has a broad host range, whereas the Wellington variant has a restricted host range. Here, we present the complete genome of X. citri subsp. citri strain AW12879. This study lays the foundation to further characterize the mechanisms for virulence and host range of X. citri.

  4. Clustering Measurements of broad-line AGNs: Review and Future

    CERN Document Server

    Krumpe, Mirko; Coil, Alison L

    2013-01-01

    Despite substantial effort, the precise physical processes that lead to the growth of super-massive black holes in the centers of galaxies are still not well understood. These phases of black hole growth are thought to be of key importance in understanding galaxy evolution. Forthcoming missions such as eROSITA, HETDEX, eBOSS, BigBOSS, LSST, and Pan-STARRS will compile by far the largest ever Active Galactic Nuclei (AGNs) catalogs which will allow us to measure the spatial distribution of AGNs in the universe with unprecedented accuracy. For the first time, AGN clustering measurements will reach a level of precision that will not only allow for an alternative approach to answering open questions in AGN/galaxy co-evolution but will open a new frontier, allowing us to precisely determine cosmological parameters. This paper reviews the large-scale clustering measurements of broad line AGNs. We summarize how clustering is measured and which constraints can be derived from AGN clustering measurements, we discuss re...

  5. 降水变化驱动下红松阔叶林土壤真菌多样性的分布格局%Effects of precipitation variation on the distribution pattern of soil fungal diversity in broad-leaved Korean pine mixed forest

    Institute of Scientific and Technical Information of China (English)

    王楠楠; 杨雪; 李世兰; 隋心; 韩士杰; 冯富娟

    2013-01-01

    红松阔叶林生态系统是中国东北地区地带性顶极植被,具有重要的生态学意义,长白山是研究温带森林对大气降水变化正负反馈的理想地带.本文以长白山原始红松阔叶林为研究对象,基于末端限制性片段长度多态性分析技术,分析了降水控制样地(增、减30%)和对照样地的0 ~5 cm和5~ 10 cm表层土和红松根际土真菌多样性的空间异质性.结果表明:降水的增加和减少均能提高土壤真菌的多样性,但优势种群有所变化.表层土中,片段长度超过500 bp的T-RFs丰度随降水增加而提高,根际土中对降水变化响应的T-RFs分别为380、455和487 bp,且根际土的响应模式较表层土复杂.典范对应分析结果表明,土壤pH、有机碳含量、总氮和有效磷等对真菌群落组成影响显著.%Broad-leaved Korean pine mixed forest is a kind of zonal climax vegetation with ecological significance in Northeast China,whereas Changbai Mountain is an ideal area to study the effects of precipitation variation on temperate forest.Taking the virgin broad-leaved Korean pine mixed forest in Changbai Mountain as the object,and based on T-RFLP method,this paper analyzed the spatial heterogeneity of fungal diversity in 0-5 cm and 5-10 cm soil layers and in rhizosphere soil at three different precipitation plots (30% increase,30% decrease,and the control).Both the increase and the decrease of precipitation increased the diversity of soil fungi,but the dominant population changed.In 0-5 cm and 5-10 cm soil layers,the T-RFs over 500 bp increased with precipitation; in rhizosphere soil,the T-RFs responded to precipitation variation were 380 bp,455 bp,and 487 bp,and the response mode was more complicated than that in surface soil layers.The results of CCA showed that the fungal community composition was significantly affected by soil pH,organic carbon,total nitrogen,and organic phosphorus.

  6. Host Integration Server 2004

    Institute of Scientific and Technical Information of China (English)

    PaulThurrott; 杨岩

    2005-01-01

    微软发布的Host Integration Server(HIS)2004,是IBM大型主机集成服务器的一个重要的更新,添加了一些重要的新特点和改进。与大多数微软公司协同工作的产品不同,HIS 2004的设计目的是为了移植,而不是纯粹的集成,事实上它将会帮助客户从现有的传统平台中得到更多的价值——在这种情况下,所指的产品就是IBM大型主机和iSeries(也就是以前的AS/400)系列机型。

  7. Ceramic Hosts for Fission Products Immobilization

    International Nuclear Information System (INIS)

    Natural spinel, perovskite and zirconolite rank among the most leach resistant of mineral forms. They also have a strong affinity for a large number of other elements and including actinides. Specimens of natural perovskite and zirconolite were radioisotope dated and found to have survived at least 2 billion years of natural process while still remain their loading of uranium and thorium . Developers of the Synroc waste form recognized and exploited the capability of these minerals to securely immobilize TRU elements in high-level waste . However, the Synroc process requires a relatively uniform input and hot pressing equipment to produce the waste form. It is desirable to develop alternative approaches to fabricate these durable waste forms to immobilize the radioactive elements. One approach is using a high temperature process to synthesize these mineral host phases to incorporate the fission products in their crystalline structures. These mineral assemblages with immobilized fission products are then isolated in a durable high temperature glass for periods measured on a geologic time scale. This is a long term research concept and will begin with the laboratory synthesis of the pure spinel (MgAl2O4), perovskite (CaTiO3) and zirconolite (CaZrTi2O7) from their constituent oxides. High temperature furnace and/or thermal plasma will be used for the synthesis of these ceramic host phases. Nonradioactive strontium oxide will be doped into these ceramic phases to investigate the development of substitutional phases such as Mg1-xSrxAl2O4, Ca1-xSrxTiO3 and Ca1-xSrxZrTi2O7. X-ray diffraction will be used to establish the crystalline structures of the pure ceramic hosts and the substitution phases. Scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) will be performed for product morphology and fission product surrogates distribution in the crystalline hosts. The range of strontium doping is planned to reach the full substitution of the divalent

  8. Ceramic Hosts for Fission Products Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Peter C Kong

    2010-07-01

    Natural spinel, perovskite and zirconolite rank among the most leach resistant of mineral forms. They also have a strong affinity for a large number of other elements and including actinides. Specimens of natural perovskite and zirconolite were radioisotope dated and found to have survived at least 2 billion years of natural process while still remain their loading of uranium and thorium . Developers of the Synroc waste form recognized and exploited the capability of these minerals to securely immobilize TRU elements in high-level waste . However, the Synroc process requires a relatively uniform input and hot pressing equipment to produce the waste form. It is desirable to develop alternative approaches to fabricate these durable waste forms to immobilize the radioactive elements. One approach is using a high temperature process to synthesize these mineral host phases to incorporate the fission products in their crystalline structures. These mineral assemblages with immobilized fission products are then isolated in a durable high temperature glass for periods measured on a geologic time scale. This is a long term research concept and will begin with the laboratory synthesis of the pure spinel (MgAl2O4), perovskite (CaTiO3) and zirconolite (CaZrTi2O7) from their constituent oxides. High temperature furnace and/or thermal plasma will be used for the synthesis of these ceramic host phases. Nonradioactive strontium oxide will be doped into these ceramic phases to investigate the development of substitutional phases such as Mg1-xSrxAl2O4, Ca1-xSrxTiO3 and Ca1-xSrxZrTi2O7. X-ray diffraction will be used to establish the crystalline structures of the pure ceramic hosts and the substitution phases. Scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) will be performed for product morphology and fission product surrogates distribution in the crystalline hosts. The range of strontium doping is planned to reach the full substitution of the divalent

  9. Apprenticeships at CERN: a host of awards

    CERN Multimedia

    2009-01-01

    This year again, two CERN apprentices have received awards at the end of their training. CERN’s broad range of technical skills means that it can provide training in a wide variety of trades and professions. Denis Fernier receives congratulations from Pierre-François Unger, Counsel state of the canton of Geneva in charge of the department of economics and health. Denis Fernier and Coralie Husi (right) at the prize-giving ceremony of the Union Industrielle de Genève.Every year, CERN hosts six technical apprentices for a four-year period: three electronics technicians and three physics lab technicians. And every year, at the end of their apprenticeships, one or more of them receives an award for being among the best apprentices in Geneva. On 23 September, two young apprentices were honoured by the Union industrielle genevoise (UIG) on passing their exams: Coralie Husi, a physics lab apprentice...

  10. Fungal sensing of host environment.

    Science.gov (United States)

    Braunsdorf, C; Mailänder-Sánchez, D; Schaller, M

    2016-09-01

    To survive inside a host, fungi have to adapt to a changing and often hostile environment and therefore need the ability to recognize what is going on around them. To adapt to different host niches, they need to sense external conditions such as temperature, pH and to recognize specific host factors. The ability to respond to physiological changes inside the host, independent of being in a commensal, pathogenic or even symbiotic context, implicates mechanisms for sensing of specific host factors. Because the cell wall is constantly in contact with the surrounding, fungi express receptors on the surface of their cell wall, such as pheromone receptors, which have important roles, besides mediating chemotropism for mating. We are not restricting the discussion to the human host because the receptors and mechanisms used by different fungal species to sense their environment are often similar even for plant pathogens. Furthermore, the natural habitat of opportunistic pathogenic fungi with the potential to cause infection in a human host is in soil and on plants. While the hosts' mechanisms of sensing fungal pathogens have been addressed in the literature, the focus of this review is to fill the gap, giving an overview on fungal sensing of a host-(ile) environment. Expanding our knowledge on host-fungal interactions is extremely important to prevent and treat diseases of pathogenic fungi, which are important issues in human health and agriculture but also to understand the delicate balance of fungal symbionts in our ecosystem. PMID:27155351

  11. Final Report: A Broad Research Project on the Sciences of Complexity, September 15, 1994 - November 15, 1999

    Energy Technology Data Exchange (ETDEWEB)

    None

    2000-02-01

    DOE support for a broad research program in the sciences of complexity permitted the Santa Fe Institute to initiate new collaborative research within its integrative core activities as well as to host visitors to participate in research on specific topics that serve as motivation and testing ground for the study of the general principles of complex systems. Results are presented on computational biology, biodiversity and ecosystem research, and advanced computing and simulation.

  12. Resident microbiota affect Bordetella pertussis infectious dose and host specificity.

    Science.gov (United States)

    Weyrich, Laura S; Feaga, Heather A; Park, Jihye; Muse, Sarah J; Safi, Chetan Y; Rolin, Olivier Y; Young, Sarah E; Harvill, Eric T

    2014-03-01

    Before contacting host tissues, invading pathogens directly or indirectly interact with host microbiota, but the effects of such interactions on the initial stages of infection are poorly understood. Bordetella pertussis is highly infectious among humans but requires large doses to colonize rodents, unlike a closely related zoonotic pathogen, Bordetella bronchiseptica, raising important questions about the contributions of bacterial competition to initial colonization and host selection. We observed that <100 colony-forming units (CFU) of B. bronchiseptica efficiently infected mice and displaced culturable host microbiota, whereas 10 000 CFU of B. pertussis were required to colonize murine nasal cavities and did not displace host microorganisms. Bacteria isolated from murine nasal cavities but not those from the human lower respiratory tract limited B. pertussis growth in vitro, indicating that interspecies competition may limit B. pertussis colonization of mice. Further, a broad-spectrum antibiotic treatment delivered before B. pertussis inoculation reduced the infectious dose to <100 CFU, and reintroduction of single Staphylococcus or Klebsiella species was sufficient to inhibit B. pertussis colonization of antibiotic-treated mice. Together, these results reveal that resident microorganisms can prevent B. pertussis colonization and influence host specificity, and they provide rationale for manipulating microbiomes to create more-accurate animal models of infectious diseases.

  13. Evolved plasmid-host interactions reduce plasmid interference cost.

    Science.gov (United States)

    Yano, Hirokazu; Wegrzyn, Katarznya; Loftie-Eaton, Wesley; Johnson, Jenny; Deckert, Gail E; Rogers, Linda M; Konieczny, Igor; Top, Eva M

    2016-09-01

    Antibiotic selection drives adaptation of antibiotic resistance plasmids to new bacterial hosts, but the molecular mechanisms are still poorly understood. We previously showed that a broad-host-range plasmid was poorly maintained in Shewanella oneidensis, but rapidly adapted through mutations in the replication initiation gene trfA1. Here we examined if these mutations reduced the fitness cost of TrfA1, and whether this was due to changes in interaction with the host's DNA helicase DnaB. The strains expressing evolved TrfA1 variants showed a higher growth rate than those expressing ancestral TrfA1. The evolved TrfA1 variants showed a lower affinity to the helicase than ancestral TrfA1 and were no longer able to activate the helicase at the oriV without host DnaA. Moreover, persistence of the ancestral plasmid was increased upon overexpression of DnaB. Finally, the evolved TrfA1 variants generated higher plasmid copy numbers than ancestral TrfA1. The findings suggest that ancestral plasmid instability can at least partly be explained by titration of DnaB by TrfA1. Thus under antibiotic selection resistance plasmids can adapt to a novel bacterial host through partial loss of function mutations that simultaneously increase plasmid copy number and decrease unfavorably high affinity to one of the hosts' essential proteins. PMID:27121483

  14. Constraints on the outer radius of the broad emission line region of active galactic nuclei

    CERN Document Server

    Landt, Hermine; Elvis, Martin; Karovska, Margarita

    2014-01-01

    Here we present observational evidence that the broad emission line region (BELR) of active galactic nuclei (AGN) generally has an outer boundary. This was already clear for sources with an obvious transition between the broad and narrow components of their emission lines. We show that the narrow component of the higher-order Paschen lines is absent in all sources, revealing a broad emission line profile with a broad, flat top. This indicates that the BELR is kinematically separate from the narrow emission line region. We use the virial theorem to estimate the BELR outer radius from the flat top width of the unblended profiles of the strongest Paschen lines, Pa alpha and Pa beta, and find that it scales with the ionising continuum luminosity roughly as expected from photoionisation theory. The value of the incident continuum photon flux resulting from this relationship corresponds to that required for dust sublimation. A flat-topped broad emission line profile is produced by both a spherical gas distribution ...

  15. Bacterial receptors for host transferrin and lactoferrin: molecular mechanisms and role in host-microbe interactions.

    Science.gov (United States)

    Morgenthau, Ari; Pogoutse, Anastassia; Adamiak, Paul; Moraes, Trevor F; Schryvers, Anthony B

    2013-12-01

    Iron homeostasis in the mammalian host limits the availability of iron to invading pathogens and is thought to restrict iron availability for microbes inhabiting mucosal surfaces. The presence of surface receptors for the host iron-binding glycoproteins transferrin (Tf) and lactoferrin (Lf) in globally important Gram-negative bacterial pathogens of humans and food production animals suggests that Tf and Lf are important sources of iron in the upper respiratory or genitourinary tracts, where they exclusively reside. Lf receptors have the additional function of protecting against host cationic antimicrobial peptides, suggesting that the bacteria expressing these receptors reside in a niche where exposure is likely. In this review we compare Tf and Lf receptors with respect to their structural and functional features, their role in colonization and infection, and their distribution among pathogenic and commensal bacteria. PMID:24266357

  16. Diversifying selection and host adaptation in two endosymbiont genomes

    Directory of Open Access Journals (Sweden)

    Slatko Barton

    2007-04-01

    Full Text Available Abstract Background The endosymbiont Wolbachia pipientis infects a broad range of arthropod and filarial nematode hosts. These diverse associations form an attractive model for understanding host:symbiont coevolution. Wolbachia's ubiquity and ability to dramatically alter host reproductive biology also form the foundation of research strategies aimed at controlling insect pests and vector-borne disease. The Wolbachia strains that infect nematodes are phylogenetically distinct, strictly vertically transmitted, and required by their hosts for growth and reproduction. Insects in contrast form more fluid associations with Wolbachia. In these taxa, host populations are most often polymorphic for infection, horizontal transmission occurs between distantly related hosts, and direct fitness effects on hosts are mild. Despite extensive interest in the Wolbachia system for many years, relatively little is known about the molecular mechanisms that mediate its varied interactions with different hosts. We have compared the genomes of the Wolbachia that infect Drosophila melanogaster, wMel and the nematode Brugia malayi, wBm to that of an outgroup Anaplasma marginale to identify genes that have experienced diversifying selection in the Wolbachia lineages. The goal of the study was to identify likely molecular mechanisms of the symbiosis and to understand the nature of the diverse association across different hosts. Results The prevalence of selection was far greater in wMel than wBm. Genes contributing to DNA metabolism, cofactor biosynthesis, and secretion were positively selected in both lineages. In wMel there was a greater emphasis on DNA repair, cell division, protein stability, and cell envelope synthesis. Conclusion Secretion pathways and outer surface protein encoding genes are highly affected by selection in keeping with host:parasite theory. If evidence of selection on various cofactor molecules reflects possible provisioning, then both insect as

  17. Molecular crosstalks in Leishmania-sandfly-host relationships

    Directory of Open Access Journals (Sweden)

    Volf P.

    2008-09-01

    Full Text Available Sandflies (Diptera: Phlebotominae are vectors of Leishmania parasites, causative agents of important human and animal diseases with diverse manifestations. This review summarizes present knowledge about the vectorial part of Leishmania life cycle and parasite transmission to the vertebrate host. Particularly, it focuses on molecules that determine the establishment of parasite infection in sandfly midgut. It describes the concept of specific versus permissive sandfly vectors, explains the epidemiological consequences of broad susceptibility of permissive sandflies and demonstrates that genetic exchange may positively affect Leishmania fitness in the vector. Last but not least, the review describes recent knowledge about circulating antibodies produced by hosts in response to sandfly bites. Studies on specificity and kinetics of antibody response revealed that anti-saliva IgG could be used as a marker of host exposure to sandflies, i.e. as a useful tool for evaluation of vector control.

  18. The application of high-resolution 3D seismic data to model the distribution of mechanical and hydrogeological properties of a potential host rock for the deep storage of radioactive waste in France

    CERN Document Server

    Mari, Jean-Luc

    2014-01-01

    In the context of a deep geological repository of high-level radioactive wastes, the French National Radioactive Waste Management Agency (Andra) has conducted an extensive characterization of the Callovo-Oxfordian argillaceous rock and surrounding formations in the Eastern Paris Basin. As part of this project, an accurate 3D seismic derived geological model is needed. The paper shows the procedure used for building the 3D seismic constrained geological model in depth by combining time-to-depth conversion of seismic horizons, consistent seismic velocity model and elastic impedance in time. It also shows how the 3D model is used for mechanical and hydrogeological studies. The 3D seismic field data example illustrates the potential of the proposed depth conversion procedure for estimating density and velocity distributions, which are consistent with the depth conversion of seismic horizons using the Bayesian Kriging method. The geological model shows good agreement with well log data obtained from a reference we...

  19. Different space preferences and within-host competition promote niche partitioning between symbiotic feather mite species.

    Science.gov (United States)

    Fernández-González, Sofía; Pérez-Rodríguez, Antón; de la Hera, Iván; Proctor, Heather C; Pérez-Tris, Javier

    2015-08-01

    Obligate symbionts (including parasites, commensals and mutualists) often share host species and host-based food resources. Such symbionts are frequently distributed unequally among hosts with different phenotypic features, or occupy different regions on a host. However, the processes leading to distinct within-host symbiont distributions remain obscure. We aimed to test whether distinct in-host symbiont distributions arise as the outcome of species-specific habitat preferences or interspecific competition, and how host phenotype influences such processes. To this end, we studied the distribution within and among individual bird hosts of two feather mites (Proctophyllodes sylviae and Trouessartia bifurcata) of migratory and sedentary European blackcaps, Sylvia atricapilla, wintering in sympatry. Trouessartia bifurcata was mostly restricted to resident blackcaps, while P. sylviae was abundant on both host types. Within hosts, each species tended to settle on different feather sectors (proximal or distal, respectively), which they filled by spreading on the wing following ordered but opposite patterns, thereby supporting the view that spatial segregation was primarily the outcome of dissimilar space preferences. However, we also found evidence of competition finely tuning mite distributions: when P. sylviae increased abundance and expanded onto the range of T. bifurcata, abundances of the two species were negatively correlated in the shared areas. In addition, the presence of T. bifurcata on a host was associated with a more restricted distribution of P. sylviae. Our results show that both species-specific preferences and interspecific interactions contribute to shaping mite distributions among and on individual hosts, a situation likely mirrored by other host-multi-symbiont systems. PMID:25980927

  20. Growth anomalies on the coral genera Acropora and Porites are strongly associated with host density and human population size across the Indo-Pacific.

    Directory of Open Access Journals (Sweden)

    Greta S Aeby

    Full Text Available Growth anomalies (GAs are common, tumor-like diseases that can cause significant morbidity and decreased fecundity in the major Indo-Pacific reef-building coral genera, Acropora and Porites. GAs are unusually tractable for testing hypotheses about drivers of coral disease because of their pan-Pacific distributions, relatively high occurrence, and unambiguous ease of identification. We modeled multiple disease-environment associations that may underlie the prevalence of Acropora growth anomalies (AGA (n = 304 surveys and Porites growth anomalies (PGA (n = 602 surveys from across the Indo-Pacific. Nine predictor variables were modeled, including coral host abundance, human population size, and sea surface temperature and ultra-violet radiation anomalies. Prevalence of both AGAs and PGAs were strongly host density-dependent. PGAs additionally showed strong positive associations with human population size. Although this association has been widely posited, this is one of the first broad-scale studies unambiguously linking a coral disease with human population size. These results emphasize that individual coral diseases can show relatively distinct patterns of association with environmental predictors, even in similar diseases (growth anomalies found on different host genera (Acropora vs. Porites. As human densities and environmental degradation increase globally, the prevalence of coral diseases like PGAs could increase accordingly, halted only perhaps by declines in host density below thresholds required for disease establishment.

  1. Growth anomalies on the coral genera Acropora and Porites are strongly associated with host density and human population size across the Indo-Pacific

    Science.gov (United States)

    Aeby, G.S.; Williams, G.J.; Franklin, E.C.; Haapkyla, J.; Harvell, C.D.; Neale, S.; Page, C.A.; Raymundo, L.; Vargas-Angel, B.; Willis, B.L.; Work, T.M.; Davy, S.K.

    2011-01-01

    Growth anomalies (GAs) are common, tumor-like diseases that can cause significant morbidity and decreased fecundity in the major Indo-Pacific reef-building coral genera, Acropora and Porites. GAs are unusually tractable for testing hypotheses about drivers of coral disease because of their pan-Pacific distributions, relatively high occurrence, and unambiguous ease of identification. We modeled multiple disease-environment associations that may underlie the prevalence of Acropora growth anomalies (AGA) (n = 304 surveys) and Porites growth anomalies (PGA) (n = 602 surveys) from across the Indo-Pacific. Nine predictor variables were modeled, including coral host abundance, human population size, and sea surface temperature and ultra-violet radiation anomalies. Prevalence of both AGAs and PGAs were strongly host density-dependent. PGAs additionally showed strong positive associations with human population size. Although this association has been widely posited, this is one of the first broad-scale studies unambiguously linking a coral disease with human population size. These results emphasize that individual coral diseases can show relatively distinct patterns of association with environmental predictors, even in similar diseases (growth anomalies) found on different host genera (Acropora vs. Porites). As human densities and environmental degradation increase globally, the prevalence of coral diseases like PGAs could increase accordingly, halted only perhaps by declines in host density below thresholds required for disease establishment.

  2. Assessing Eli Broad's Assault on Public School System Leadership

    Science.gov (United States)

    English, Fenwick W.; Crowder, Zan

    2012-01-01

    Eli Broad's approach to reforming urban public education does not recognize his own self-interest in promoting changes within such educational systems, a classic problem of misrecognition. The Broad agenda is an assault on the notion of the mission of public education as a service instead of a for-profit enterprise concerned with making money for…

  3. Social Cognition, Social Skill, and the Broad Autism Phenotype

    Science.gov (United States)

    Sasson, Noah J.; Nowlin, Rachel B.; Pinkham, Amy E.

    2013-01-01

    Social-cognitive deficits differentiate parents with the "broad autism phenotype" from non-broad autism phenotype parents more robustly than other neuropsychological features of autism, suggesting that this domain may be particularly informative for identifying genetic and brain processes associated with the phenotype. The current study…

  4. Boot Camp for Education CEOs: The Broad Foundation Superintendents Academy

    Science.gov (United States)

    Jehlen, Alain

    2012-01-01

    The Broad Foundation Superintendents Academy is the most prominent and most controversial training institute for school chiefs. The Academy is the flagship program of the Eli and Edythe Broad Foundation, the smallest of a triumvirate of corporate foundations that are at the heart of the billionaire campaign to remake public education in the image…

  5. 云南省19县(市)小板纤恙螨地区分布及宿主选择研究%Research on the Area Distribution and Host Selection of Leptotrombidium scutellare in 19 Counties of Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    詹银珠; 郭宪国; 左小华; 王乔花; 吴滇

    2011-01-01

    In order to investigate the area distribution and host selection of Leptotrombidium scutellare in Yunnan Province, a field survey was carried out during 2001 to 2009, based on different geographic location, topography, climate and ecological characteristics. A total of 16 491 L scutellare were captured from the body surface of 9 838 small mammal hosts of 7 families, 18 genera, and 30 species in 4 orders, accounted for 17.73%(16 491/92 990) of all chigger mites collected. L. scutellare distributed in 12 counties, more in the northwest and south of the Province Although L scutellare could parasitize on different small mammal species, most of them were on Eothenomys miletus and Apodemus chevrieri.%根据云南省不同地理方位、地形地貌、气候与生态等特点,于2001-2009年选取19县(市)为调查点,诱捕小兽,收集其耳廓和外耳道的全部恙螨,分析小板纤恙螨(Leptotrombidium scutellare)在不同宿主、不同地区的分布情况.结果,在捕获的4目7科18属30种9 838只小兽体表采集到小板纤恙螨16 491只,占所有恙螨的17.73%(16491/92990).在调查的19县(市)中,12个县(市)有小板纤恙螨分布,主要分布于云南西北部和南部的高海拔、低气温、低降水量地区.小板纤恙螨寄生宿主广泛,主要宿主为大绒鼠(Eothenomys miletus)和齐氏姬鼠(Apode mus chevrieri).

  6. The economie impact of immigration for the host countries

    OpenAIRE

    Chojnicki, Xavier

    2004-01-01

    In this paper, we will investigate the economic consequences of immigration for the host countries. Recently, the debate has been centered on the role of immigration in the process of aging. A priori, the immigration of workers is likely to affect the economic situation of the host country in multiple ways, both positive and negative. Most studies focused on the labor market reveal a weak net gain of immigration whose distribution depends on the skill structure of immigrants and domestic labo...

  7. Screening and analysis of genes expressed upon infection of broad bean with Clover yellow vein virus causing lethal necrosis

    Directory of Open Access Journals (Sweden)

    Suzuki Yuji

    2011-07-01

    Full Text Available Abstract Clover yellow vein virus (ClYVV causes lethal systemic necrosis in legumes, including broad bean (Vicia faba and pea (Pisum sativum. To identify host genes involved in necrotic symptom expression after ClYVV infection, we screened cDNA fragments in which expression was changed in advance of necrotic symptom expression in broad bean (V. faba cv. Wase using the differential display technique and secondarily with Northern blot analysis. Expression changes were confirmed in 20 genes, and the six that exhibited the most change were analyzed further. These six genes included a gene that encodes a putative nitrate-induced NOI protein (VfNOI, and another was homologous to an Arabidopsis gene that encodes a glycine- and proline-rich protein GPRP (VfGPRP. We recently reported that necrotic symptom development in ClYVV-infected pea is associated with expression of salicylic acid (SA-dependent pathogenesis-related (PR proteins and requires SA-dependent host responses. Interestingly, VfNOI and VfGPRP expression was correlated with that of the putative SA-dependent PR proteins in ClYVV-infected broad bean. However, broad bean infected with a recombinant ClYVV expressing the VfGPRP protein showed weaker symptoms and less viral multiplication than that infected with ClYVV expressing the GFP protein. These results imply that VfGPRP plays a role in defense against ClYVV rather than in necrotic symptom expression.

  8. Screening and analysis of genes expressed upon infection of broad bean with Clover yellow vein virus causing lethal necrosis.

    Science.gov (United States)

    Nakahara, Kenji S; Kitazawa, Hiroaki; Atsumi, Go; Choi, Sun Hee; Suzuki, Yuji; Uyeda, Ichiro

    2011-01-01

    Clover yellow vein virus (ClYVV) causes lethal systemic necrosis in legumes, including broad bean (Vicia faba) and pea (Pisum sativum). To identify host genes involved in necrotic symptom expression after ClYVV infection, we screened cDNA fragments in which expression was changed in advance of necrotic symptom expression in broad bean (V. faba cv. Wase) using the differential display technique and secondarily with Northern blot analysis. Expression changes were confirmed in 20 genes, and the six that exhibited the most change were analyzed further. These six genes included a gene that encodes a putative nitrate-induced NOI protein (VfNOI), and another was homologous to an Arabidopsis gene that encodes a glycine- and proline-rich protein GPRP (VfGPRP). We recently reported that necrotic symptom development in ClYVV-infected pea is associated with expression of salicylic acid (SA)-dependent pathogenesis-related (PR) proteins and requires SA-dependent host responses. Interestingly, VfNOI and VfGPRP expression was correlated with that of the putative SA-dependent PR proteins in ClYVV-infected broad bean. However, broad bean infected with a recombinant ClYVV expressing the VfGPRP protein showed weaker symptoms and less viral multiplication than that infected with ClYVV expressing the GFP protein. These results imply that VfGPRP plays a role in defense against ClYVV rather than in necrotic symptom expression. PMID:21767375

  9. HostPhinder: A Phage Host Prediction Tool

    DEFF Research Database (Denmark)

    Villarroel, Julia; Kleinheinz, Kortine Annina; Jurtz, Vanessa Isabell;

    2016-01-01

    phages. As a measure of genomic similarity the number of co-occurring k-mers (DNA sequences of length k) is used. Using an independent evaluation set, HostPhinder was able to correctly predict host genus and species for 81% and 74% of the phages respectively, giving predictions for more phages than BLAST...

  10. [Tuberculosis in compromised hosts].

    Science.gov (United States)

    2003-11-01

    Recent development of tuberculosis in Japan tends to converge on a specific high risk group. The proportion of tuberculosis developing particularly from the compromised hosts in the high risk group is especially high. At this symposium, therefore, we took up diabetes mellitus, gastrectomy, dialysis, AIDS and the elderly for discussion. Many new findings and useful reports for practical medical treatment are submitted; why these compromised hosts are predisposed to tuberculosis, tuberculosis diagnostic and remedial notes of those compromised hosts etc. It is an important question for the future to study how to prevent tuberculosis from these compromised hosts. 1. Tuberculosis in diabetes mellitus: aggravation and its immunological mechanism: Kazuyoshi KAWAKAMI (Department of Internal Medicine, Division of Infectious Diseases, Graduate School and Faculty of Medicine, University of the Ryukyus). It has been well documented that diabetes mellitus (DM) is a major aggravating factor in tuberculosis. The onset of this disease is more frequent in DM patients than in individuals with any underlying diseases. However, the precise mechanism of this finding remains to be fully understood. Earlier studies reported that the migration, phagocytosis and bactericidal activity of neutrophils are all impaired in DM patients, which is related to their reduced host defense to infection with extracellular bacteria, such as S. aureus and E. colli. Host defense to mycobacterial infection is largely mediated by cellular immunity, and Th1-related cytokines, such as IFN-gamma and IL-12, play a central role in this response. It is reported that serum level of these cytokines and their production by peripheral blood mononuclear cells (PBMC) are reduced in tuberculosis patients with DM, and this is supposed to be involved in the high incidence of tuberculosis in DM. Our study observed similar findings and furthermore indicated that IFN-gamma and IL-12 production by BCG-stimulated PBMC was lower

  11. Citrus tristeza virus-host interactions

    Directory of Open Access Journals (Sweden)

    William O. Dawson

    2013-05-01

    Full Text Available Citrus tristeza virus (CTV is a phloem-limited virus whose natural host range is restricted to citrus and related species. Although the virus has killed millions of trees, almost destroying whole industries, and continually limits production in many citrus growing areas, most isolates are mild or symptomless in most of their host range. There is little understanding of how the virus causes severe disease in some citrus and none in others. Movement and distribution of CTV differs considerably from that of well-studied viruses of herbaceous plants where movement occurs largely through adjacent cells. In contrast, CTV systemically infects plants mainly by long-distance movement with only limited cell-to-cell movement. The virus is transported through sieve elements and occasionally enters an adjacent companion or phloem parenchyma cell where virus replication occurs. In some plants this is followed by cell-to-cell movement into only a small cluster of adjacent cells, while in others there is no cell-to-cell movement. Different proportions of cells adjacent to sieve elements become infected in different plant species. This appears to be related to how well viral gene products interact with specific hosts. CTV has three genes that are not necessary for infection of most of its hosts, but are needed in different combinations for infection of certain citrus species. These genes apparently were acquired by the virus to extend its host range. Some specific viral gene products have been implicated in symptom induction. Remarkably, the deletion of these genes from the virus genome can induce large increases in stem pitting symptoms. The p23 gene, which is a suppressor of RNA silencing and a regulator of viral RNA synthesis, has been shown to be the cause of seedling yellows symptoms in sour orange. Most isolates of CTV in nature are populations of different strains of CTV. The next frontier of CTV biology is the understanding how the virus variants in

  12. The cellular immune response of Daphnia magna under host-parasite genetic variation and variation in initial dose

    OpenAIRE

    Auld, Stuart K. J. R.; Kai H. Edel; Tom J Little

    2012-01-01

    In invertebrate-parasite systems, the likelihood of infection following parasite exposure is often dependent on the specific combination of host and parasite genotypes (termed genetic specificity). Genetic specificity can maintain diversity in host and parasite populations and is a major component of the Red Queen hypothesis. However, invertebrate immune systems are thought to only distinguish between broad classes of parasite. Using a natural host-parasite system with a well-established patt...

  13. The macroecology of infectious diseases: a new perspective on global-scale drivers of pathogen distributions and impacts.

    Science.gov (United States)

    Stephens, Patrick R; Altizer, Sonia; Smith, Katherine F; Alonso Aguirre, A; Brown, James H; Budischak, Sarah A; Byers, James E; Dallas, Tad A; Jonathan Davies, T; Drake, John M; Ezenwa, Vanessa O; Farrell, Maxwell J; Gittleman, John L; Han, Barbara A; Huang, Shan; Hutchinson, Rebecca A; Johnson, Pieter; Nunn, Charles L; Onstad, David; Park, Andrew; Vazquez-Prokopec, Gonzalo M; Schmidt, John P; Poulin, Robert

    2016-09-01

    Identifying drivers of infectious disease patterns and impacts at the broadest scales of organisation is one of the most crucial challenges for modern science, yet answers to many fundamental questions remain elusive. These include what factors commonly facilitate transmission of pathogens to novel host species, what drives variation in immune investment among host species, and more generally what drives global patterns of parasite diversity and distribution? Here we consider how the perspectives and tools of macroecology, a field that investigates patterns and processes at broad spatial, temporal and taxonomic scales, are expanding scientific understanding of global infectious disease ecology. In particular, emerging approaches are providing new insights about scaling properties across all living taxa, and new strategies for mapping pathogen biodiversity and infection risk. Ultimately, macroecology is establishing a framework to more accurately predict global patterns of infectious disease distribution and emergence. PMID:27353433

  14. Efficient, designable, and broad-bandwidth optical extinction via aspect-ratio-tailored silver nanodisks

    OpenAIRE

    Anquillare, E. L.; Miller, O D; Hsu, C. W.; DeLacy, B. G.; Joannopoulos, J. D.; Johnson, S. G.; Soljacic, M.

    2016-01-01

    Subwavelength resonators, ranging from single atoms to metallic nanoparticles, typically exhibit a narrow-bandwidth response to optical excitations. We computationally design and experimentally synthesize tailored distributions of silver nanodisks to extinguish light over broad and varied frequency windows. We show that metallic nanodisks are two-to-ten-times more efficient in absorbing and scattering light than common structures, and can approach fundamental limits to broadband scattering fo...

  15. 制度环境、 投资动机与中国 OFDI区位分布——基于发达东道国和发展中东道国的对比研究%Institutional Environment, Investment Motivation and Locational Distribution of China′s OFDI——Based on the Comparison of Developed Host Countries and Developing Host Countries

    Institute of Scientific and Technical Information of China (English)

    王琳; 钱晓英

    2016-01-01

    本文基于2004-2013年中国对45个东道国的OFDI数据, 利用Heckman两阶段模型对比分析中国OFDI在发达东道国与发展中东道国间的区位分布, 并考察不同投资动机下东道国制度对中国企业投资选择和规模的作用. 实证结果发现: 市场、 资源、 技术、 制度都是影响中国在发达国家投资的区位因素, 除技术外, 其他三项对中国在发展中国家的OFDI也有影响; 发达国家的制度质量及其与中国的双边制度差距正向影响中国企业投资规模, 而发展中国家的腐败程度负向影响中国OFDI规模, 双边制度差异的作用尚不明显; 制度环境对中国在发达国家的市场、 资源寻求型投资有显著积极影响, 但对技术寻求型投资以及在发展中国家的市场、 资源寻求型OFDI有消极影响.%Based on China′s outward foreign direct investment ( OFDI ) flow data of 45 host countries during 2004-2013, this article makes the comparative analysis of regional distribution of China′s OFDI in developing and developed countries, with the method of Heckman two-stage model, and studies if the political institutions of host countries have an impact on investment choice and scale of China′s OFDI with different investment motivations.The results show that mar-ket, resource, technology and institution are the location factors affecting Chinese investment in developed countries, and they also affect the investment in developing countries besides technology;both institutional quality and the bilateral in-stitutional distance have positive impact on Chinese investment scale in developed countries;however corruption level of developing countries affect China′s OFDI negatively, the role of bilateral institutional distance is not clear; institutional environment has positive impact on Chinese market-seeking, resource-seeking investment in developed countries, but it has a negative effect on technology-seeking OFDI and market

  16. 制度环境、 投资动机与中国 OFDI区位分布——基于发达东道国和发展中东道国的对比研究%Institutional Environment, Investment Motivation and Locational Distribution of China′s OFDI——Based on the Comparison of Developed Host Countries and Developing Host Countries

    Institute of Scientific and Technical Information of China (English)

    王琳; 钱晓英

    2016-01-01

    Based on China′s outward foreign direct investment ( OFDI ) flow data of 45 host countries during 2004-2013, this article makes the comparative analysis of regional distribution of China′s OFDI in developing and developed countries, with the method of Heckman two-stage model, and studies if the political institutions of host countries have an impact on investment choice and scale of China′s OFDI with different investment motivations.The results show that mar-ket, resource, technology and institution are the location factors affecting Chinese investment in developed countries, and they also affect the investment in developing countries besides technology;both institutional quality and the bilateral in-stitutional distance have positive impact on Chinese investment scale in developed countries;however corruption level of developing countries affect China′s OFDI negatively, the role of bilateral institutional distance is not clear; institutional environment has positive impact on Chinese market-seeking, resource-seeking investment in developed countries, but it has a negative effect on technology-seeking OFDI and market-seeking, resource-seeking investment in developing coun-tries.%本文基于2004-2013年中国对45个东道国的OFDI数据, 利用Heckman两阶段模型对比分析中国OFDI在发达东道国与发展中东道国间的区位分布, 并考察不同投资动机下东道国制度对中国企业投资选择和规模的作用. 实证结果发现: 市场、 资源、 技术、 制度都是影响中国在发达国家投资的区位因素, 除技术外, 其他三项对中国在发展中国家的OFDI也有影响; 发达国家的制度质量及其与中国的双边制度差距正向影响中国企业投资规模, 而发展中国家的腐败程度负向影响中国OFDI规模, 双边制度差异的作用尚不明显; 制度环境对中国在发达国家的市场、 资源寻求型投资有显著积极影响, 但对技术寻求型投资以及

  17. Ecological Distribution of Collembola in the Litter under Different Ground Cover Treatment of Evergreen Broad-leaved Forest%天童常绿阔叶林砍伐后凋落物层跳虫群落生态学研究

    Institute of Scientific and Technical Information of China (English)

    靳亚丽; 蒋跃

    2016-01-01

    Objective] To understand the effects of ground cover removal on collembola communities in the litter and the community restoration situations. [Method] The collembola community investigation of 4 seasons in an evergreen broad-leaved forest after 7 years since the ground cover removal in Tiantong Region, Zhejiang Province was carried out during Dec. 2019-Sep. 2010. The five treatments in five sites were as follows:(Ⅰ) big trees were removed but sprouts retained;(Ⅱ) ground surface vegetation was removed but litter retained;(Ⅲ) all vegetation and 0–10 cm topsoil were removed;(Ⅳ) undergrowth was removed but big trees retained; and (Ⅴ) a control plot without any disturbance. [Result] The number of collembolan groups did not vary widely. The number of collembola community was as follows:Ⅱ(28. 79%) > Ⅳ(21. 03%) >Ⅰ(20. 75%) > Ⅴ(17. 09%) >Ⅲ(12. 33%) . The community composition vary in different seasons. The number of collembola community was as follows:autumn > summer > spring > winter. The organic carbon, total nitrogen and total phosphorus had obvious differences among the plots. Even after 7 years of restoration, the collembola community traits were obviously different among the treatments. [ Conclusion] Collembola community was very sensitive to the environmental disturbing, which can be used as the indicator species to evaluate the soil environmental dis-turbance.%[目的]了解不同砍伐处理对常绿阔叶林凋落物层跳虫群落结构的影响以及各处理样地跳虫群落恢复状况。[方法]于2009年12月至2010年9月在浙江天童地区常绿阔叶林5个砍伐7年后的恢复样地进行四季采样,对浙江森林公园不同砍伐处理下常绿阔叶林土壤动物优势类群跳虫群落进行调查。样地处理分别为:(Ⅰ)去除大树保留萌枝、(Ⅱ)去除地表植物保留枯枝落叶层、(Ⅲ)去除地表植物和10 cm表土、(Ⅳ)清除下木层保留大树、(Ⅴ)对照。[结果]各处理样地各科

  18. Tracing the incidence of X-ray AGN and their distribution of accretion rates across the galaxy population

    Science.gov (United States)

    Aird, James; Coil, Alison; Georgakakis, Antonis; Nandra, Kirpal

    2016-08-01

    X-ray selection provides a powerful method of identifying AGN across a variety of host galaxies and with a wide range of accretion rates. However, careful consideration of the underlying selection biases are vital to reveal the true underlying distribution of accretion rates and determine how the incidence of AGN is related to the properties of the galaxies that host them. I will present new measurements of the distribution of specific accretion rates (scaled relative to the total host galaxy mass, roughly tracing the Eddington ratio) within both star-forming and quiescent galaxy populations. We combine near-infrared selected samples of galaxies from the CANDELS/3D-HST and UltraVISTA surveys with deep Chandra X-ray data and use an advanced Bayesian technique to constrain the underlying distribution of specific accretion rates as a function of stellar mass and redshift. Our results reveal a broad distribution of accretion rates (reflecting long-term variability in the level of AGN fuelling) in both galaxy types. The probability of a star-forming galaxy hosting an AGN (above a fixed specific accretion rate) has a strong stellar mass dependence - revealing an intrinsically higher incidence of AGN in massive star-forming galaxies - and undergoes a stellar-mass-dependent evolution with redshift. The probability of a quiescent galaxy hosting an AGN is generally lower but does not depend on stellar mass and evolves differently with redshift. These results provide vital insights into the relationship between the growth of black hole and the physical properties of their host galaxies.

  19. Host factors in nidovirus replication

    NARCIS (Netherlands)

    Wilde, Adriaan Hugo de

    2013-01-01

    The interplay between nidoviruses and the infected host cell was investigated. Arterivirus RNA-synthesising activity was shown to depend on intact membranes and on a cytosolic host protein which does not cosediment with the RTC. Furthermore, the immunosuppressant drug cyclosporin A (CsA) blocks repl

  20. Larval helminths in intermediate hosts

    DEFF Research Database (Denmark)

    Fredensborg, Brian Lund; Poulin, R

    2005-01-01

    Density-dependent effects on parasite fitness have been documented from adult helminths in their definitive hosts. There have, however, been no studies on the cost of sharing an intermediate host with other parasites in terms of reduced adult parasite fecundity. Even if larval parasites suffer a ...

  1. Stennis hosts 2010 Special Olympics

    Science.gov (United States)

    2010-01-01

    Sarah Johnson, 28, of Gulfport, carries in the Olympic torch to signal the start of the 2010 Area III Special Olympic games at NASA's John C. Stennis Space Center on March 27. Stennis volunteers hosted special needs athletes from across the area for the event. Stennis is an annual host of the games.

  2. Host state incentives and compensation:

    International Nuclear Information System (INIS)

    After reviewing several options for selecting a host state, the Commission elected to proceed with anoption that builds upon developing grass-roots acceptance and support. To foster such support the Commission has adopted an incentives and compensation package. The purpose of the package is that the incentives and compensations offered are designed to encourage an objective and unbiased review of accepting the responsibilities of a host state or community, and the package helps to guarantee that a facility will become a state/community asset and not impose economic, environmenta, or social hardships for the host community. This report, which describes the Commission's host state incentive and compensation package, the monetary benefit to the host community and state will be substantial. Community benefits will exceed $40 million over 20 years and benefits to the state will be approximately $24 million over the 20-year expected life of the facility. 10 refs., 4 tabs

  3. Industrial power distribution

    Energy Technology Data Exchange (ETDEWEB)

    Sorrells, M.A.

    1990-01-01

    This paper is a broad overview of industrial power distribution. Primary focus will be on selection of the various low voltage components to achieve the end product. Emphasis will be on the use of national standards to ensure a safe and well designed installation.

  4. Lichenicolous fungi show population subdivision by host species but do not share population history with their hosts.

    Science.gov (United States)

    Werth, Silke; Millanes, Ana María; Wedin, Mats; Scheidegger, Christoph

    2013-01-01

    Lichenicolous fungi are a species-rich biological group growing on lichen thalli. Here, we analyze the genetic structure of the lichenicolous basidiomycete Tremella lobariacearum and three host species (Lobaria pulmonaria, Lobaria macaronesica, and Lobaria immixta) in Macaronesia. We used ordination and analysis of molecular variance to investigate the structuring of genetic variation, and a simulation test to investigate whether rDNA haplotypes of T. lobariacearum were significantly associated with host species. To investigate the evolutionary and demographic history of the lichenicolous fungus and its hosts, we used coalescent samplers to generate trees, and Bayesian skyline plots. We found that the hosts were most important in structuring populations of the lichenicolous species. Despite their wide geographic distribution, the same haplotypes of T. lobariacearum consistently associated with a given host species. Our results suggest that the Lobaria hosts create a selective environment for the lichenicolous fungus. Both the pathogen and the host populations exhibited substantial genetic structure. However, evolutionary and demographic histories differed between the parasite and its hosts, as evidenced by different divergence times and tree topologies. PMID:23332835

  5. X-Ray Emitting GHz-Peaked Spectrum Galaxies: Testing a Dynamical-Radiative Model with Broad-Band Spectra

    Energy Technology Data Exchange (ETDEWEB)

    Ostorero, L.; /Turin U. /INFN, Turin; Moderski, R.; /Warsaw, Copernicus Astron. Ctr. /KIPAC, Menlo Park; Stawarz, L.; /KIPAC, Menlo Park /Jagiellonian U., Astron. Observ.; Diaferio, A.; /Turin U. /INFN, Turin; Kowalska, I.; /Warsaw U. Observ.; Cheung, C.C.; /NASA, Goddard /Naval Research Lab, Wash., D.C.; Kataoka, J.; /Waseda U., RISE; Begelman, M.C.; /JILA, Boulder; Wagner, S.J.; /Heidelberg Observ.

    2010-06-07

    In a dynamical-radiative model we recently developed to describe the physics of compact, GHz-Peaked-Spectrum (GPS) sources, the relativistic jets propagate across the inner, kpc-sized region of the host galaxy, while the electron population of the expanding lobes evolves and emits synchrotron and inverse-Compton (IC) radiation. Interstellar-medium gas clouds engulfed by the expanding lobes, and photoionized by the active nucleus, are responsible for the radio spectral turnover through free-free absorption (FFA) of the synchrotron photons. The model provides a description of the evolution of the GPS spectral energy distribution (SED) with the source expansion, predicting significant and complex high-energy emission, from the X-ray to the {gamma}-ray frequency domain. Here, we test this model with the broad-band SEDs of a sample of eleven X-ray emitting GPS galaxies with Compact-Symmetric-Object (CSO) morphology, and show that: (i) the shape of the radio continuum at frequencies lower than the spectral turnover is indeed well accounted for by the FFA mechanism; (ii) the observed X-ray spectra can be interpreted as non-thermal radiation produced via IC scattering of the local radiation fields off the lobe particles, providing a viable alternative to the thermal, accretion-disk dominated scenario. We also show that the relation between the hydrogen column densities derived from the X-ray (N{sub H}) and radio (N{sub HI}) data of the sources is suggestive of a positive correlation, which, if confirmed by future observations, would provide further support to our scenario of high-energy emitting lobes.

  6. Ultra-broad bandwidth parametric amplification at degeneracy.

    Science.gov (United States)

    Limpert, J; Aguergaray, C; Montant, S; Manek-Hönninger, I; Petit, S; Descamps, D; Cormier, E; Salin, F

    2005-09-19

    We report on a novel approach of ultra-broad bandwidth parametric amplification around degeneracy. A bandwidth of up to 400 nm centered around 800 nm is amplified in a BBO crystal by using chirped pump pulses with a bandwitdth as broad as 10 nm. A supercontinuum signal is generated in a microstructured fiber, having to first order a quadratic chirp, which is necessary to ensure temporal overlap of the interacting waves over this broad bandwidth. Furthermore, we discuss the potential of this approach for an octave-spanning parametric amplification.

  7. Broad Ligament Pregnancy - Success Story of a Laparoscopically Managed Case.

    Science.gov (United States)

    Nayar, Jayashree; Nair, Sobha S

    2016-07-01

    Abdominal pregnancies constitute 1% of ectopic pregnancies, among which broad ligament pregnancy is a rare form. The maternal mortality rate has been reported to be as high as 20%. The diagnosis is seldom established before surgery. Laparoscopic management of broad ligament ectopic pregnancy is the ideal form of treatment in appropriately selected patients. We present the case report of successful laparoscopic treatment of a 3x3.5cm broad ligament pregnancy. A search of literature shows that ours is the 6(th) case report of such a rare ectopic pregnancy managed endoscopically successfully. PMID:27630914

  8. Ultra-broad bandwidth parametric amplification at degeneracy.

    Science.gov (United States)

    Limpert, J; Aguergaray, C; Montant, S; Manek-Hönninger, I; Petit, S; Descamps, D; Cormier, E; Salin, F

    2005-09-19

    We report on a novel approach of ultra-broad bandwidth parametric amplification around degeneracy. A bandwidth of up to 400 nm centered around 800 nm is amplified in a BBO crystal by using chirped pump pulses with a bandwitdth as broad as 10 nm. A supercontinuum signal is generated in a microstructured fiber, having to first order a quadratic chirp, which is necessary to ensure temporal overlap of the interacting waves over this broad bandwidth. Furthermore, we discuss the potential of this approach for an octave-spanning parametric amplification. PMID:19498762

  9. A novel, broad-spectrum inhibitor of enterovirus replication that targets host cell factor phosphatidylinositol 4-kinase IIIβ

    NARCIS (Netherlands)

    van der Schaar, H.M.; Leyssen, Pieter; Thibaut, H.J.; de Palma, Armando; van der Linden, Lonneke; Lanke, Kjerstin H.W.; Lacroix, Céline; Verbeken, Erik; Conrath, Katja; Macleod, Angus M; Mitchell, Dale R; Palmer, Nicholas J; van de Poël, Hervé; Andrews, Martin; Neyts, Johan; van Kuppeveld, F.J.M.

    2013-01-01

    Despite their high clinical and socioeconomic impacts, there is currently no approved antiviral therapy for the prophylaxis or treatment of enterovirus infections. Here we report on a novel inhibitor of enterovirus replication, compound 1, 2-fluoro-4-(2-methyl-8-(3-(methylsulfonyl)benzylamino)imidaz

  10. Broadly Neutralizing Antibody Responses in a Large Longitudinal Sub-Saharan HIV Primary Infection Cohort.

    Directory of Open Access Journals (Sweden)

    Elise Landais

    2016-01-01

    Full Text Available Broadly neutralizing antibodies (bnAbs are thought to be a critical component of a protective HIV vaccine. However, designing vaccines immunogens able to elicit bnAbs has proven unsuccessful to date. Understanding the correlates and immunological mechanisms leading to the development of bnAb responses during natural HIV infection is thus critical to the design of a protective vaccine. The IAVI Protocol C program investigates a large longitudinal cohort of primary HIV-1 infection in Eastern and South Africa. Development of neutralization was evaluated in 439 donors using a 6 cross-clade pseudo-virus panel predictive of neutralization breadth on larger panels. About 15% of individuals developed bnAb responses, essentially between year 2 and year 4 of infection. Statistical analyses revealed no influence of gender, age or geographical origin on the development of neutralization breadth. However, cross-clade neutralization strongly correlated with high viral load as well as with low CD4 T cell counts, subtype-C infection and HLA-A*03(- genotype. A correlation with high overall plasma IgG levels and anti-Env IgG binding titers was also found. The latter appeared not associated with higher affinity, suggesting a greater diversity of the anti-Env responses in broad neutralizers. Broadly neutralizing activity targeting glycan-dependent epitopes, largely the N332-glycan epitope region, was detected in nearly half of the broad neutralizers while CD4bs and gp41-MPER bnAb responses were only detected in very few individuals. Together the findings suggest that both viral and host factors are critical for the development of bnAbs and that the HIV Env N332-glycan supersite may be a favorable target for vaccine design.

  11. The host galaxies of AGN with powerful relativistic jets

    Science.gov (United States)

    Olguín-Iglesias, A.; León-Tavares, J.; Kotilainen, J. K.; Chavushyan, V.; Tornikoski, M.; Valtaoja, E.; Añorve, C.; Valdés, J.; Carrasco, L.

    2016-08-01

    We present deep Near-infrared (NIR) images of a sample of 19 intermediate-redshift (0.310^27 WHz^-1), previously classified as flat-spectrum radio quasars. We also compile host galaxy and nuclear magnitudes for blazars from literature. The combined sample (this work and compilation) contains 100 radio-loud AGN with host galaxy detections and a broad range of radio luminosities L1.4GHz = 10^23.7 - 10^28.3WHz^-1, allowing us to divide our sample into high-excitation (quasar-mode; HERGs) and low-excitation (radio-mode; LERGs) radio galaxies. The host galaxies of our sample are bright and seem to follow the Kormendy relation. Nuclear emission (dominated by non-thermal mechanisms) and host-galaxy magnitudes show a slightly negative weak trend for LERGs. On the other hand, the m_bulge -m_nuc relation is statistically significant for HERGs. Although it may be affected by selection effects, this correlation suggests a close coupling between the relativistic jets and their host galaxy. Our findings are consistent with the excitation state (LERG/HERG) scenario. In this view, LERGs emit the bulk of their energy in the form of radio jets, producing a strong feedback mechanism, and HERGs are affected by galaxy mergers and interactions, which provide a common supply of cold gas to feed both nuclear activity and star formation episodes.

  12. Broad Spectrum Sanitizing Wipes with Food Additives Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Microcide proposes to develop novel multipurpose non-toxic sanitizing wipes that are aqueous based, have shelf life of 3-5 years, have broad spectrum microbicidal...

  13. AGN Broad Line Regions Scale with Bolometric Luminosity

    CERN Document Server

    Trippe, Sascha

    2015-01-01

    The masses of supermassive black holes in active galactic nuclei (AGN) can be derived spectroscopically via virial mass estimators based on selected broad optical/ultraviolet emission lines. These estimates commonly use the line width as a proxy for the gas speed and the monochromatic continuum luminosity as a proxy for the radius of the broad line region. However, if the size of the broad line region scales with bolometric rather than monochromatic AGN luminosity, mass estimates based on different emission lines will show a systematic discrepancy which is a function of the color of the AGN continuum. This has actually been observed in mass estimates based on H-alpha / H-beta and C IV lines, indicating that AGN broad line regions indeed scale with bolometric luminosity. Given that this effect seems to have been overlooked as yet, currently used single-epoch mass estimates are likely to be biased.

  14. Host Ranges of the IncN Group Plasmid pCU1 and Its Minireplicon in Gram-Negative Purple Bacteria

    OpenAIRE

    Krishnan, B. Rajendra; Iyer, V. N.

    1988-01-01

    The bacterial host ranges of the conjugatively self-transmissible IncN group plasmid pCU1 and its mobilizable miniderivative, pCU785, were examined. Species of the gram-negative purple bacteria were chosen for this study. Conjugative mobilization of pCU785 into a wide variety of bacteria was facilitated by the presence of oriT of the broad-host-range plasmid RK2 in pCU785. Although the host range of the IncN tra system of pCU1 is broad, the host range of its replicon is limited. However, the ...

  15. Guest-host interactions between dichroic dyes and anisotropic hosts

    International Nuclear Information System (INIS)

    The guest-host interaction between dichroic dyes and anistropic hosts has been investigated by means of optical spectroscopy. Two different TCNQ adducts; 2-{4-[(2,6-dimethylmorpholin-4-yl)(4-metylpiperidin-1-yl) methylene]cyclohexa-2,5-dien-1-ylidene} malononitrile (MORPIP) and 2-{4-[cyclohex-1-yltetrahydropyrimidin-2(1H-ylidene] cyclohexa-2,5-dien-1-ylidine} malononitrile (AMINO) have been examined dispersed in a range of nematic liquid crystal mixtures. The result is a substantial impact on the absorption and luminescence when compared to the situation in isotropic solvents. The excited state decay exhibits a complex behaviour showing a multi-exponential decay of the time-resolved luminescence. The photoluminescence quantum yields of the chromophores, also shows strong host dependence. For AMINO, we observe a trend which is indicative of a viscosity dependence. The observations are discussed in view of different solvent-solute interactions between guest and host

  16. Planet Host Stars: Mass, Age and Kinematics

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    We determine the mass, age and kinematics of 51 extra-solar planet host stars. The results are then used to search for signs of connection of the data with metallicity and to investigate the population nature. We find that the increase in mean metallicity with stellar mass is similar to that in normal field stars, so it seems unsuitable to use this relation as a constraint on the theory of planet formation. The age and kinematic distributions seem to favour the metallicity of extra-solar planet host stars being initial. Although the kinematic data of these stars indicate their origin from two populations - the thin and the thick disks, kinematics may not help in the maintenance of the planet around the host. Stars with planets, brown dwarfs or stellar companions are sorted into three groups and re-investigated separately for their formation mechanism. The main results indicate that stars with M2 < 25MJ have [Fe/H] > -0.1 and a wide period range, but there are no other differences.Thus, there does not seem to be any physically distinguishable characteristics among the three star groups.

  17. Hosts and parasites as aliens.

    Science.gov (United States)

    Taraschewski, H

    2006-06-01

    Over the past decades, various free-living animals (hosts) and their parasites have invaded recipient areas in which they had not previously occurred, thus gaining the status of aliens or exotics. In general this happened to a low extent for hundreds of years. With variable frequency, invasions have been followed by the dispersal and establishment of non-indigenous species, whether host or parasite. In the literature thus far, colonizations by both hosts and parasites have not been treated and reviewed together, although both are usually interwoven in various ways. As to those factors permitting invasive success and colonization strength, various hypotheses have been put forward depending on the scientific background of respective authors and on the conspicuousness of certain invasions. Researchers who have tried to analyse characteristic developmental patterns, the speed of dispersal or the degree of genetic divergence in populations of alien species have come to different conclusions. Among parasitologists, the applied aspects of parasite invasions, such as the negative effects on economically important hosts, have long been at the centre of interest. In this contribution, invasions by hosts as well as parasites are considered comparatively, revealing many similarities and a few differences. Two helminths, the liver fluke, Fasciola hepatica, of cattle and sheep and the swimbladder nematode, Anguillicola crassus, of eels are shown to be useful as model parasites for the study of animal invasions and environmental global change. Introductions of F. hepatica have been associated with imports of cattle or other grazing animals. In various target areas, susceptible lymnaeid snails serving as intermediate hosts were either naturally present and/or were introduced from the donor continent of the parasite (Europe) and/or from other regions which were not within the original range of the parasite, partly reflecting progressive stages of a global biota change. In several

  18. Greening File Distribution: Centralized or Distributed?

    CERN Document Server

    Verma, Kshitiz; Anta, Antonio Fernández; Rumín, Rubén Cuevas; Azcorra, Arturo

    2011-01-01

    Despite file-distribution applications are responsible for a major portion of the current Internet traffic, so far little effort has been dedicated to study file distribution from the point of view of energy efficiency. In this paper, we present a first approach at the problem of energy efficiency for file distribution. Specifically, we first demonstrate that the general problem of minimizing energy consumption in file distribution in heterogeneous settings is NP-hard. For homogeneous settings, we derive tight lower bounds on energy consumption, and we design a family of algorithms that achieve these bounds. Our results prove that collaborative p2p schemes achieve up to 50% energy savings with respect to the best available centralized file distribution scheme. Through simulation, we demonstrate that in more realistic cases (e.g., considering network congestion, and link variability across hosts) we validate this observation, since our collaborative algorithms always achieve significant energy savings with res...

  19. Host specialization and phylogenetic diversity of Corynespora cassiicola.

    Science.gov (United States)

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

    2009-09-01

    The fungus Corynespora cassiicola is primarily found in the tropics and subtropics, and is widely diverse in substrate utilization and host association. Isolate characterization within C. cassiicola was undertaken to investigate how genetic diversity correlates with host specificity, growth rate, and geographic distribution. C. cassiicola isolates were collected from 68 different plant species in American Samoa, Brazil, Malaysia, and Micronesia, and Florida, Mississippi, and Tennessee within the United States. Phylogenetic analyses using four loci were performed with 143 Corynespora spp. isolates, including outgroup taxa obtained from culture collections: C. citricola, C. melongenae, C. olivacea, C. proliferata, C. sesamum, and C. smithii. Phylogenetic trees were congruent from the ribosomal DNA internal transcribed spacer region, two random hypervariable loci (caa5 and ga4), and the actin-encoding locus act1, indicating a lack of recombination within the species and asexual propagation. Fifty isolates were tested for pathogenicity on eight known C. cassiicola crop hosts: basil, bean, cowpea, cucumber, papaya, soybean, sweet potato, and tomato. Pathogenicity profiles ranged from one to four hosts, with cucumber appearing in 14 of the 16 profiles. Bootstrap analyses and Bayesian posterior probability values identified six statistically significant phylogenetic lineages. The six phylogenetic lineages correlated with host of origin, pathogenicity, and growth rate but not with geographic location. Common fungal genotypes were widely distributed geographically, indicating long-distance and global dispersal of clonal lineages. This research reveals an abundance of previously unrecognized genetic diversity within the species and provides evidence for host specialization on papaya. PMID:19671003

  20. The predictability of phytophagous insect communities: host specialists as habitat specialists.

    Directory of Open Access Journals (Sweden)

    Jörg Müller

    Full Text Available The difficulties specialized phytophagous insects face in finding habitats with an appropriate host should constrain their dispersal. Within the concept of metacommunities, this leads to the prediction that host-plant specialists should sort into local assemblages according to the local environmental conditions, i.e. habitat conditions, whereas assemblages of host-plant generalists should depend also on regional processes. Our study aimed at ranking the importance of local environmental factors and species composition of the vegetation for predicting the species composition of phytophagous moth assemblages with either a narrow or a broad host range. Our database consists of 351,506 specimens representing 820 species of nocturnal Macrolepidoptera sampled between 1980 and 2006 using light traps in 96 strict forest reserves in southern Germany. Species were grouped as specialists or generalists according to the food plants of the larvae; specialists use host plants belonging to one genus. We used predictive canonical correspondence and co-correspondence analyses to rank the importance of local environmental factors, the species composition of the vegetation and the role of host plants for predicting the species composition of host-plant specialists and generalists. The cross-validatory fit for predicting the species composition of phytophagous moths was higher for host-plant specialists than for host-plant generalists using environmental factors as well as the composition of the vegetation. As expected for host-plant specialists, the species composition of the vegetation was a better predictor of the composition of these assemblages than the environmental variables. But surprisingly, this difference for specialized insects was not due to the occurrence of their host plants. Overall, our study supports the idea that owing to evolutionary constraints in finding a host, host-plant specialists and host-plant generalists follow two different models of

  1. A slowly evolving host moves first in symbiotic interactions

    Science.gov (United States)

    Damore, James; Gore, Jeff

    2011-03-01

    Symbiotic relationships, both parasitic and mutualistic, are ubiquitous in nature. Understanding how these symbioses evolve, from bacteria and their phages to humans and our gut microflora, is crucial in understanding how life operates. Often, symbioses consist of a slowly evolving host species with each host only interacting with its own sub-population of symbionts. The Red Queen hypothesis describes coevolutionary relationships as constant arms races with each species rushing to evolve an advantage over the other, suggesting that faster evolution is favored. Here, we use a simple game theoretic model of host- symbiont coevolution that includes population structure to show that if the symbionts evolve much faster than the host, the equilibrium distribution is the same as it would be if it were a sequential game where the host moves first against its symbionts. For the slowly evolving host, this will prove to be advantageous in mutualisms and a handicap in antagonisms. The model allows for symbiont adaptation to its host, a result that is robust to changes in the parameters and generalizes to continuous and multiplayer games. Our findings provide insight into a wide range of symbiotic phenomena and help to unify the field of coevolutionary theory.

  2. Age consistency between exoplanet hosts and field stars

    CERN Document Server

    Bonfanti, Andrea; Nascimbeni, Valerio

    2015-01-01

    Transiting planets around stars are discovered mostly through photometric surveys. Unlike radial velocity surveys, photometric surveys do not tend to target slow rotators, inactive and metal-rich stars. Nevertheless, we suspect that observational biases could impact also transiting-planet hosts. This paper aims at evaluating how selection effects reflect on the evolutionary stage of both a limited sample of transiting-planet host stars (TPH) and a wider sample of planet-hosting stars detected through radial velocity analysis. Then, thanks to uniform derivation of stellar ages, a homogeneous comparison between exoplanet hosts and field star age distributions is developed. Stellar parameters have been computed through our custom-developed isochrone placement algorithm, according to Padova evolutionary models. The notable aspects of our algorithm include the treatment of element diffusion, activity checks in terms of $\\log{R'_{HK}}$ and $v\\sin{i}$ and the evaluation of the stellar evolutionary speed in the Hertz...

  3. Nanoporous Anodic Alumina 3D FDTD Modelling for a Broad Range of Inter-pore Distances.

    Science.gov (United States)

    Bertó-Roselló, Francesc; Xifré-Pérez, Elisabet; Ferré-Borrull, Josep; Pallarès, Josep; Marsal, Lluis F

    2016-12-01

    The capability of the finite difference time domain (FDTD) method for the numerical modelling of the optical properties of nanoporous anodic alumina (NAA) in a broad range of inter-pore distances is evaluated. FDTD permits taking into account in the same numerical framework all the structural features of NAA, such as the texturization of the interfaces or the incorporation of electrolyte anions in the aluminium oxide host. The evaluation is carried out by comparing reflectance measurements from two samples with two very different inter-pore distances with the simulation results. Results show that considering the texturization is crucial to obtain good agreement with the measurements. On the other hand, including the anionic layer in the model leads to a second-order contribution to the reflectance spectrum. PMID:27518230

  4. Nanoporous Anodic Alumina 3D FDTD Modelling for a Broad Range of Inter-pore Distances

    Science.gov (United States)

    Bertó-Roselló, Francesc; Xifré-Pérez, Elisabet; Ferré-Borrull, Josep; Pallarès, Josep; Marsal, Lluis F.

    2016-08-01

    The capability of the finite difference time domain (FDTD) method for the numerical modelling of the optical properties of nanoporous anodic alumina (NAA) in a broad range of inter-pore distances is evaluated. FDTD permits taking into account in the same numerical framework all the structural features of NAA, such as the texturization of the interfaces or the incorporation of electrolyte anions in the aluminium oxide host. The evaluation is carried out by comparing reflectance measurements from two samples with two very different inter-pore distances with the simulation results. Results show that considering the texturization is crucial to obtain good agreement with the measurements. On the other hand, including the anionic layer in the model leads to a second-order contribution to the reflectance spectrum.

  5. Peracetic Acid Treatment Generates Potent Inactivated Oral Vaccines from a Broad Range of Culturable Bacterial Species.

    Science.gov (United States)

    Moor, Kathrin; Wotzka, Sandra Y; Toska, Albulena; Diard, Médéric; Hapfelmeier, Siegfried; Slack, Emma

    2016-01-01

    Our mucosal surfaces are the main sites of non-vector-borne pathogen entry, as well as the main interface with our commensal microbiota. We are still only beginning to understand how mucosal adaptive immunity interacts with commensal and pathogenic microbes to influence factors such as infectivity, phenotypic diversity, and within-host evolution. This is in part due to difficulties in generating specific mucosal adaptive immune responses without disrupting the mucosal microbial ecosystem itself. Here, we present a very simple tool to generate inactivated mucosal vaccines from a broad range of culturable bacteria. Oral gavage of 10(10) peracetic acid-inactivated bacteria induces high-titer-specific intestinal IgA in the absence of any measurable inflammation or species invasion. As a proof of principle, we demonstrate that this technique is sufficient to provide fully protective immunity in the murine model of invasive non-typhoidal Salmonellosis, even in the face of severe innate immune deficiency. PMID:26904024

  6. Introduction to Distribution and Ecology of Sterile Conks of Inonotus obliquus.

    Science.gov (United States)

    Lee, Min-Woong; Hur, Hyeon; Chang, Kwang-Choon; Lee, Tae-Soo; Ka, Kang-Hyeon; Jankovsky, L

    2008-12-01

    Inonotus obliquus is a fungus that causes white heart rot on several broad-leaved species. This fungus forms typical charcoal-black, sterile conks (chaga) or cinder conks on infected stems of the birche (Betula spp). The dark brown pulp of the sterile conk is formed by a pure mycelial mass of fungus. Chaga are a folk remedy in Russia, reflecting the circumboreal distribution of I. obliquus in boreal forest ecosystems on Betula spp. and in meridional mountain forests on beech (Fagus spp.) in Russia, Scandinavia, Central Europe, and Eastern Europe. Distribution at lower latitudes in Western and Southern Europe, Northern America, Asia, Japan, and Korea is rare. Infected trees grow for many years without several symptoms of decline. The infection can penetrate through stem injuries with exterior sterile conks developing later. In the Czech Republic, cinder conk is found on birches inhabiting peat bogs and in mountain areas with a colder and more humid climate, although it is widespread in other broad leaved species over the Czech Republic. The most common hosts are B. pendula, B. pubescens, B. carpatica, and F. sylvatica. Less frequent hosts include Acer campestre, Acer pseudoplatanus, Alnus glutinosa, Alnus incana, Fraxinus excelsior, Quercus cerris, Q. petraea, Q. robur, Q. delachampii, and Ulmus sp.

  7. Bid Optimization in Broad-Match Ad auctions

    CERN Document Server

    Even-dar, Eyal; Mirrokni, Vahab; Muthukrishnan, S; Nadav, Uri

    2009-01-01

    Ad auctions in sponsored search support ``broad match'' that allows an advertiser to target a large number of queries while bidding only on a limited number. While giving more expressiveness to advertisers, this feature makes it challenging to optimize bids to maximize their returns: choosing to bid on a query as a broad match because it provides high profit results in one bidding for related queries which may yield low or even negative profits. We abstract and study the complexity of the {\\em bid optimization problem} which is to determine an advertiser's bids on a subset of keywords (possibly using broad match) so that her profit is maximized. In the query language model when the advertiser is allowed to bid on all queries as broad match, we present an linear programming (LP)-based polynomial-time algorithm that gets the optimal profit. In the model in which an advertiser can only bid on keywords, ie., a subset of keywords as an exact or broad match, we show that this problem is not approximable within any ...

  8. Genomic Diversity of Streptoccocus agalactiae Isolates from Multiple Hosts and Their Infectivity in Nile Tilapia

    Science.gov (United States)

    Streptococcus agalactiae, the Lancefield group B Streptococcus (GBS), has a broad host range and can be pathogenic to numerous animals, including fish. GBS is most recognized for causing cattle mastitis and human neonatal meningitis, it also causes fatal meningo-encephalitis in fish. We investigat...

  9. Broad ligament pregnancy a diagnostic dilemma: a case report

    Directory of Open Access Journals (Sweden)

    Amit Gupta

    2016-07-01

    Full Text Available Broad ligament pregnancy is one of the rarest forms of ectopic pregnancy with high risk of maternal mortality. Although ultrasonography is usually helpful in making the diagnosis but it is mostly established during laparotomy. 34 year old G2P1 with previous caesarean section reported at 8th month of pregnancy with inability to perceive foetal movements. Ultrasonography confirmed intrauterine fetal demise. Patient was taken for caesarean section after failed induction. Intraoperative diagnosis of broad ligament pregnancy was made and broad ligament along with fetus, sac, fallopian tube and ovary was excised. Post-operative period was uneventful. [Int J Reprod Contracept Obstet Gynecol 2016; 5(7.000: 2478-2480

  10. Folded cavity angled-grating broad-area lasers.

    Science.gov (United States)

    Zhao, Yunsong; Zhu, Lin

    2013-10-01

    The angled-grating broad-area laser is a promising candidate for high power, high brightness diode laser source. The key point in the design is the angled gratings which can simultaneously support the unique snake-like zigzag lasing mode and eliminate the direct Fabry-Perot (FP) feedback. Unlike a conventional laser waveguide mode, the phase front of the zigzag mode periodically changes along the propagation direction. By use of the mirror symmetry of the zigzag mode, we propose and demonstrate the folded cavity angled-grating broad-area lasers. One benefit of this design is to reduce the required wafer space compared to a regular angled-grating broad-area laser, especially in a long cavity laser for high power operation. Experimental results show that the folded cavity laser exhibits good beam quality in far field with a slightly larger threshold and smaller slope efficiency due to the additional interface loss.

  11. Cellular host responses to gliomas.

    Directory of Open Access Journals (Sweden)

    Joseph Najbauer

    Full Text Available BACKGROUND: Glioblastoma multiforme (GBM is the most aggressive type of malignant primary brain tumors in adults. Molecular and genetic analysis has advanced our understanding of glioma biology, however mapping the cellular composition of the tumor microenvironment is crucial for understanding the pathology of this dreaded brain cancer. In this study we identified major cell populations attracted by glioma using orthotopic rodent models of human glioma xenografts. Marker-specific, anatomical and morphological analyses revealed a robust influx of host cells into the main tumor bed and tumor satellites. METHODOLOGY/PRINCIPAL FINDINGS: Human glioma cell lines and glioma spheroid orthotopic implants were used in rodents. In both models, the xenografts recruited large numbers of host nestin-expressing cells, which formed a 'network' with glioma. The host nestin-expressing cells appeared to originate in the subventricular zone ipsilateral to the tumor, and were clearly distinguishable from pericytes that expressed smooth muscle actin. These distinct cell populations established close physical contact in a 'pair-wise' manner and migrated together to the deeper layers of tumor satellites and gave rise to tumor vasculature. The GBM biopsy xenografts displayed two different phenotypes: (a low-generation tumors (first in vivo passage in rats were highly invasive and non-angiogenic, and host nestin-positive cells that infiltrated into these tumors displayed astrocytic or elongated bipolar morphology; (b high-generation xenografts (fifth passage had pronounced cellularity, were angiogenic with 'glomerulus-like' microvascular proliferations that contained host nestin-positive cells. Stromal cell-derived factor-1 and its receptor CXCR4 were highly expressed in and around glioma xenografts, suggesting their role in glioma progression and invasion. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate a robust migration of nestin-expressing host cells to glioma, which

  12. The blue host galaxy of the red GRB 000418

    DEFF Research Database (Denmark)

    Gorosabel, J.; Klose, S.; Christensen, L.;

    2003-01-01

    We report on multi-band (UBVRIZJ(s)K(s)) observations of the host galaxy of the April 18, 2000 gamma-ray burst. The Spectral Energy Distribution (SED) is analysed by fitting empirical and synthetic spectral templates. We find that: (i) the best SED fit is obtained with a starburst template, (ii) ...

  13. Analysis of fuel system technology for broad property fuels

    Science.gov (United States)

    Coffinberry, G. A.

    1984-01-01

    An analytical study was performed in order to assess relative performance and economic factors involved with alternative advanced fuel systems for future commercial aircraft operating with broad property fuels. Significant results, with emphasis on design practicality from the engine manufacturer' standpoint, are highlighted. Several advanced fuel systems were modeled to determine as accurately as possible the relative merits of each system from the standpoint of compatibility with broad property fuel. Freezing point, thermal stability, and lubricity were key property issues. A computer model was formulated to determine the investment incentive for each system. Results are given.

  14. Functions of antimicrobial peptides in host defense and immunity.

    Science.gov (United States)

    Beisswenger, Christoph; Bals, Robert

    2005-06-01

    Antimicrobial peptides (AMPs) are effector molecules of the innate immune system. AMPs have a broad antimicrobial spectrum and lyse microbial cells by interaction with biomembranes. Besides their direct antimicrobial function, they have multiple roles as mediators of inflammation with impact on epithelial and inflammatory cells influencing diverse processes such as cytokine release, cell proliferation, angiogenesis, wound healing, chemotaxis, immune induction, and protease-antiprotease balance. Furthermore, AMPs qualify as prototypes of innovative drugs that may be used as antibiotics, anti-lipopolysaccharide drugs, or modifiers of inflammation. This review summarizes the current knowledge about the basic and applied biology of antimicrobial peptides and discusses features of AMPs in host defense and inflammation.

  15. Human DDX3 protein is a valuable target to develop broad spectrum antiviral agents.

    Science.gov (United States)

    Brai, Annalaura; Fazi, Roberta; Tintori, Cristina; Zamperini, Claudio; Bugli, Francesca; Sanguinetti, Maurizio; Stigliano, Egidio; Esté, José; Badia, Roger; Franco, Sandra; Martinez, Miguel A; Martinez, Javier P; Meyerhans, Andreas; Saladini, Francesco; Zazzi, Maurizio; Garbelli, Anna; Maga, Giovanni; Botta, Maurizio

    2016-05-10

    Targeting a host factor essential for the replication of different viruses but not for the cells offers a higher genetic barrier to the development of resistance, may simplify therapy regimens for coinfections, and facilitates management of emerging viral diseases. DEAD-box polypeptide 3 (DDX3) is a human host factor required for the replication of several DNA and RNA viruses, including some of the most challenging human pathogens currently circulating, such as HIV-1, Hepatitis C virus, Dengue virus, and West Nile virus. Herein, we showed for the first time, to our knowledge, that the inhibition of DDX3 by a small molecule could be successfully exploited for the development of a broad spectrum antiviral agent. In addition to the multiple antiviral activities, hit compound 16d retained full activity against drug-resistant HIV-1 strains in the absence of cellular toxicity. Pharmacokinetics and toxicity studies in rats confirmed a good safety profile and bioavailability of 16d. Thus, DDX3 is here validated as a valuable therapeutic target. PMID:27118832

  16. Gammaherpesviral gene expression and virion composition are broadly controlled by accelerated mRNA degradation.

    Directory of Open Access Journals (Sweden)

    Emma Abernathy

    2014-01-01

    Full Text Available Lytic gammaherpesvirus infection restricts host gene expression by promoting widespread degradation of cytoplasmic mRNA through the activity of the viral endonuclease SOX. Though generally assumed to be selective for cellular transcripts, the extent to which SOX impacts viral mRNA stability has remained unknown. We addressed this issue using the model murine gammaherpesvirus MHV68 and, unexpectedly, found that all stages of viral gene expression are controlled through mRNA degradation. Using both comprehensive RNA expression profiling and half-life studies we reveal that the levels of the majority of viral mRNAs but not noncoding RNAs are tempered by MHV68 SOX (muSOX activity. The targeting of viral mRNA by muSOX is functionally significant, as it impacts intracellular viral protein abundance and progeny virion composition. In the absence of muSOX-imposed gene expression control the viral particles display increased cell surface binding and entry as well as enhanced immediate early gene expression. These phenotypes culminate in a viral replication defect in multiple cell types as well as in vivo, highlighting the importance of maintaining the appropriate balance of viral RNA during gammaherpesviral infection. This is the first example of a virus that fails to broadly discriminate between cellular and viral transcripts during host shutoff and instead uses the targeting of viral messages to fine-tune overall gene expression.

  17. Asteroseismology of Exoplanet Host Stars

    CERN Document Server

    Huber, Daniel

    2015-01-01

    Asteroseismology is among the most powerful observational tools to determine fundamental properties of stars. Space-based photometry has recently enabled the systematic detection of oscillations in exoplanet host stars, allowing a combination of asteroseismology with transit and radial-velocity measurements to characterize planetary systems. In this contribution I will review the key synergies between asteroseismology and exoplanet science such as the precise determination of radii and ages of exoplanet host stars, as well as applications of asteroseismology to measure spin-orbit inclinations in multiplanet systems and orbital eccentricities of small planets. Finally I will give a brief outlook on asteroseismic studies of exoplanet hosts with current and future space-based missions such as K2 and TESS.

  18. Host receptors for bacteriophage adsorption.

    Science.gov (United States)

    Bertozzi Silva, Juliano; Storms, Zachary; Sauvageau, Dominic

    2016-02-01

    The adsorption of bacteriophages (phages) onto host cells is, in all but a few rare cases, a sine qua non condition for the onset of the infection process. Understanding the mechanisms involved and the factors affecting it is, thus, crucial for the investigation of host-phage interactions. This review provides a survey of the phage host receptors involved in recognition and adsorption and their interactions during attachment. Comprehension of the whole infection process, starting with the adsorption step, can enable and accelerate our understanding of phage ecology and the development of phage-based technologies. To assist in this effort, we have established an open-access resource--the Phage Receptor Database (PhReD)--to serve as a repository for information on known and newly identified phage receptors. PMID:26755501

  19. Desert bird associations with broad-scale boundary length: Applications in avian conservation

    Science.gov (United States)

    Gutzwiller, K.J.; Barrow, W.C.

    2008-01-01

    1. Current understanding regarding the effects of boundaries on bird communities has originated largely from studies of forest-non-forest boundaries in mesic systems. To assess whether broad-scale boundary length can affect bird community structure in deserts, and to identify patterns and predictors of species' associations useful in avian conservation, we studied relations between birds and boundary-length variables in Chihuahuan Desert landscapes. Operationally, a boundary was the border between two adjoining land covers, and broad-scale boundary length was the total length of such borders in a large area. 2. Within 2-km radius areas, we measured six boundary-length variables. We analysed bird-boundary relations for 26 species, tested for assemblage-level patterns in species' associations with boundary-length variables, and assessed whether body size, dispersal ability and cowbird-host status were correlates of these associations. 3. The abundances or occurrences of a significant majority of species were associated with boundary-length variables, and similar numbers of species were related positively and negatively to boundary-length variables. 4. Disproportionately small numbers of species were correlated with total boundary length, land-cover boundary length and shrubland-grassland boundary length (variables responsible for large proportions of boundary length). Disproportionately large numbers of species were correlated with roadside boundary length and riparian vegetation-grassland boundary length (variables responsible for small proportions of boundary length). Roadside boundary length was associated (positively and negatively) with the most species. 5. Species' associations with boundary-length variables were not correlated with body size, dispersal ability or cowbird-host status. 6. Synthesis and applications. For the species we studied, conservationists can use the regressions we report as working models to anticipate influences of boundary-length changes

  20. Broad spectral range synchronized flat-top arrayed waveguide grating

    NARCIS (Netherlands)

    Akca, B. Imran; Doerr, Christopher R.; Pollnau, Markus; Ridder, de René M.

    2012-01-01

    A broad-band Mach-Zehnder-interferometer-synchronized flat-top arrayed waveguide grating is presented with a 0.5-dB bandwidth of 12 nm over 90 nm of spectral range and a central excess loss value of -0.5 dB.

  1. Model Invariance across Genders of the Broad Autism Phenotype Questionnaire

    Science.gov (United States)

    Broderick, Neill; Wade, Jordan L.; Meyer, J. Patrick; Hull, Michael; Reeve, Ronald E.

    2015-01-01

    ASD is one of the most heritable neuropsychiatric disorders, though comprehensive genetic liability remains elusive. To facilitate genetic research, researchers employ the concept of the broad autism phenotype (BAP), a milder presentation of traits in undiagnosed relatives. Research suggests that the BAP Questionnaire (BAPQ) demonstrates…

  2. Children and trauma : a broad perspective on exposure and recovery

    NARCIS (Netherlands)

    Alisic, E.

    2011-01-01

    The purpose of this dissertation was to generate a broad overview of children’s exposure to and recovery from trauma in order to promote theory building and the design of prevention and intervention activities. First, a general population study was conducted in 1770 primary school children. They fil

  3. Document understanding for a broad class of documents

    NARCIS (Netherlands)

    Aiello, Marco; Monz, Christof; Todoran, Leon; Worring, Marcel

    2002-01-01

    We present a document analysis system able to assign logical labels and extract the reading order in a broad set of documents. All information sources, from geometric features and spatial relations to the textual features and content are employed in the analysis. To deal effectively with these infor

  4. Broad-band hard X-ray reflectors

    DEFF Research Database (Denmark)

    Joensen, K.D.; Gorenstein, P.; Hoghoj, P.;

    1997-01-01

    Interest in optics for hard X-ray broad-band application is growing. In this paper, we compare the hard X-ray (20-100 keV) reflectivity obtained with an energy-dispersive reflectometer, of a standard commercial gold thin-film with that of a 600 bilayer W/Si X-ray supermirror. The reflectivity of ...

  5. Silver Nanoparticles with Broad Multiband Linear Optical Absorption

    KAUST Repository

    Bakr, Osman M.

    2009-07-06

    A simple one-pot method produces silver nanoparticles coated with aryl thiols that show intense, broad nonplasmonic optical properties. The synthesis works with many aryl-thiol capping ligands, including water-soluble 4-mercaptobenzoic acid. The nanoparticles produced show linear absorption that is broader, stronger, and more structured than most conventional organic and inorganic dyes.

  6. PRINCIPAR An Efficient, Broad-coverage, Principle-based Parser

    CERN Document Server

    Lin, D

    1994-01-01

    We present an efficient, broad-coverage, principle-based parser for English. The parser has been implemented in C++ and runs on SUN Sparcstations with X-windows. It contains a lexicon with over 90,000 entries, constructed automatically by applying a set of extraction and conversion rules to entries from machine readable dictionaries.

  7. Cloud-Hosted Real-time Data Services for the Geosciences (CHORDS)

    Science.gov (United States)

    Daniels, M. D.; Graves, S. J.; Kerkez, B.; Chandrasekar, V.; Vernon, F.; Martin, C. L.; Maskey, M.; Keiser, K.; Dye, M. J.

    2015-12-01

    The Cloud-Hosted Real-time Data Services for the Geosciences (CHORDS) project, funded as part of NSF's EarthCube initiative, addresses the ever-increasing importance of real-time scientific data, particularly in mission critical scenarios, where informed decisions must be made rapidly. Advances in the distribution of real-time data are leading many new transient phenomena in space-time to be observed, however, real-time decision-making is infeasible in many cases as these streaming data are either completely inaccessible or only available to proprietary in-house tools or displays. This lack of accessibility prohibits advanced algorithm and workflow development that could be initiated or enhanced by these data streams. Small research teams do not have resources to develop tools for the broad dissemination of their valuable real-time data and could benefit from an easy to use, scalable, cloud-based solution to facilitate access. CHORDS proposes to make a very diverse suite of real-time data available to the broader geosciences community in order to allow innovative new science in these areas to thrive. This presentation will highlight recently developed CHORDS portal tools and processing systems aimed at addressing some of the gaps in handling real-time data, particularly in the provisioning of data from the "long-tail" scientific community through a simple interface deployed in the cloud. The CHORDS system will connect these real-time streams via standard services from the Open Geospatial Consortium (OGC) and does so in a way that is simple and transparent to the data provider. Broad use of the CHORDS framework will expand the role of real-time data within the geosciences, and enhance the potential of streaming data sources to enable adaptive experimentation and real-time hypothesis testing. Adherence to community data and metadata standards will promote the integration of CHORDS real-time data with existing standards-compliant analysis, visualization and modeling

  8. Dispersão de Biomphalaria straminea, hospedeira intermediária do Schistosoma mansoni, através da distribuição de peixes The spreading of Biomphalaria straminea, intermediate host of Schistosoma mansoni through the distribution of fishes

    Directory of Open Access Journals (Sweden)

    Renato de R. Corrêa

    1970-12-01

    Full Text Available Foi focalizado, pela primeira vez o encontro de B. straminea no Estado de São Paulo. Esta espécie vem juntar-se aos planorbídeos já assinalados em nosso Estado. Foram descritos os criadouros, onde a B. straminea foi coletada, localizados em tanques de criação de peixes nas Estações de Piscicultura de Barra Bonita e Americana, Estado de São Paulo, e em um aquário particular na capital dêsse Estado. Fêz-se referência ao transporte de peixes oriundos de zonas do país onde ocorre aquela espécie, Amazonas e Ceará, como responsável pela introdução daquele molusco no Estado. Destacou-se êsse achado pelo perigo que representa a distribuição de peixes da maneira como vem sendo feita atualmente em nosso país, tendo sido julgado necessário o estabelecimento de quarentena para aquêles vindos de zonas infestadas por espécies hospedeiras intermediárias do S. mansoni. Foram relatadas as medidas de combate aos caramujos efetuadas imediatamente após aquela descoberta e os resultados obtidos. Conclui-se que a dispersão passiva da B. straminea pelo transporte de peixes, deve ampliar a distribuição geográfica dêsse planorbídeo, já assinalado na Venezuela, Guianas e no Brasil, sendo que neste último ocorre em tôdas as Unidades Federativas, exceto, no Rio Grande do Sul, Santa Catarina, Rio de Janeiro e Territórios.Up the present, the works of collecting planorbids done in 226 municipalities for the elaboration of the geographical distribution chart in the State of São Paulo (Brazil, showed the presence of two intermediate host species of Schistosoma mansoni: Biomphalaria tenagophila and Biompralaria glabrata. Although the technicians from the Psiculture Stations, have not found snails in the water inside the containers used for the transportation of fishes, the ecological conditions of B. straminea in the latest researches are such as to indicate that they have been introduced, in our State through fish transportation imported

  9. The Inflammasome in Host Defense

    Directory of Open Access Journals (Sweden)

    Gang Chen

    2009-12-01

    Full Text Available Nod-like receptors have emerged as an important family of sensors in host defense. These receptors are expressed in macrophages, dendritic cells and monocytes and play an important role in microbial immunity. Some Nod-like receptors form the inflammasome, a protein complex that activates caspase-1 in response to several stimuli. Caspase-1 activation leads to processing and secretion of pro-inflammatory cytokines such as interleukin (IL-1β and IL-18. Here, we discuss recent advances in the inflammasome field with an emphasis on host defense. We also compare differential requirements for inflammasome activation in dendritic cells, macrophages and monocytes.

  10. Probing the Inner Structure of Polar Broad Absorption-Line Quasars

    Science.gov (United States)

    Ghosh, Kajal

    2008-10-01

    We have discovered a sample of polar broad absorption-line quasars (BALQSOs). We know their inclination angles with reasonable certainty. Thus, these are the ideal objects to probe their inner structure through the X-ray studies. However, to date, we do not have a reasonably good signal-to-noise ratio X-ray spectrum of any of these objects. Here, we propose deep XMM-Newton observations of four polar BALQSOs to study the physical processes responsible for the X-ray emission, distribution of BAL clouds, wind driven mechanism, jet entrainment, etc. Finally, all these results will be used to constrain our time-dependent hydrodynamical simulations.

  11. Efficient broad- and tunable-bandwidth optical extinction via aspect-ratio-tailored silver nanodisks

    CERN Document Server

    Anquillare, Emma L; Hsu, Chia Wei; DeLacy, Brendan G; Joannopoulos, John D; Soljacic, Marin

    2015-01-01

    Sub-wavelength resonators typically exhibit a narrow-bandwidth response to optical excitations. We computationally design and experimentally synthesize tailored distributions of silver nanodisks to extinguish light over broad, tunable frequency windows. We show that metallic nanodisks are two- to twenty-times more efficient in absorbing and scattering light than common structures. Per-volume efficiency increases away from the plasma frequency of the underlying metal. We measure broadband extinction per volume that closely approaches theoretical predictions over three representative visible-range wavelength windows, confirming the high efficiency of nanodisks and demonstrating the collective power of computational design and experimental precision for developing new photonics technologies.

  12. Efficient, designable, and broad-bandwidth optical extinction via aspect-ratio-tailored silver nanodisks

    CERN Document Server

    Anquillare, E L; Hsu, C W; DeLacy, B G; Joannopoulos, J D; Johnson, S G; Soljacic, M

    2016-01-01

    Subwavelength resonators, ranging from single atoms to metallic nanoparticles, typically exhibit a narrow-bandwidth response to optical excitations. We computationally design and experimentally synthesize tailored distributions of silver nanodisks to extinguish light over broad and varied frequency windows. We show that metallic nanodisks are two-to-ten-times more efficient in absorbing and scattering light than common structures, and can approach fundamental limits to broadband scattering for subwavelength particles. We measure broadband extinction per volume that closely approaches theoretical predictions over three representative visible-range wavelength windows, confirming the high efficiency of nanodisks and demonstrating the collective power of computational design and experimental precision for developing new photonics technologies.

  13. Real Time Host Assessment using ANN for Grid Network

    Directory of Open Access Journals (Sweden)

    T.R.Srinivasan

    2010-10-01

    Full Text Available In this work, we study the efficacy of assessing registered hosts for job allocation using Artificial neural network to classify registered hosts during job scheduling. Grid is evolving as the computing structure of the future. The success in commercial grid computing is the ability to negotiate resource sharing arrangements with a set of registered participating parties. Grid computing is capable of integrating services across distributed heterogeneous disparate resources with a centralized control to provide quality of service.Host assessment plays a crucial role to assign a specific job in thegrid. Host selection among the registered pool of hosts can drastically improve the quality of service. Resource discoveryalgorithms are available but identifying ideal resource to reducequeue time and response time is the most essential task in a commercial grid environment. Resource mining is the process of running data through sophisticated algorithms to uncover meaningful patterns and co relations that may otherwise be hidden. We explore theapplication of these techniques to assess host by training thesystem with known data. Experimental results show an improvement of 25.49 percent in data classification using ANN over normal methods.

  14. Host insect species of Ophiocordyceps sinensis: a review

    Directory of Open Access Journals (Sweden)

    Xiao-Liang Wang

    2011-09-01

    Full Text Available Ophiocordyceps sinensis (≡ Cordyceps sinensis is one of the most valued medicinal fungi in China, used for its invigorating effects in strengthening the body and restoring energy. The fungus parasitizes larvae of moths and converts them into sclerotia from which the fungus fruiting body grows. Since the late 1950s, considerable effort has been devoted to the study of host insects related to the fungus. In the present paper, the research history of insect species associated with O. sinensis is briefly reviewed and an extensive literature survey is presented. Ninety-one insect names, spanning 13 genera, related to host insects of O. sinensis are investigated. The relationships between the reported insect species and O. sinensis are analyzed. Fifty-seven of these are considered as recognizable potential host species of the fungus distributed throughout the Tibetan Plateau, whilst eight are considered as indeterminate hosts and 26 as non-hosts. Among the names of recognizable potential host insects, three are invalid (nomen nudum and require further study. This work provides basic information for management of the insect resources and for the conservation and sustainable use of O. sinensis.

  15. Adaptation of a polyphagous herbivore to a novel host plant extensively shapes the transcriptome of herbivore and host.

    Science.gov (United States)

    Wybouw, Nicky; Zhurov, Vladimir; Martel, Catherine; Bruinsma, Kristie A; Hendrickx, Frederik; Grbić, Vojislava; Van Leeuwen, Thomas

    2015-09-01

    Generalist arthropod herbivores rapidly adapt to a broad range of host plants. However, the extent of transcriptional reprogramming in the herbivore and its hosts associated with adaptation remains poorly understood. Using the spider mite Tetranychus urticae and tomato as models with available genomic resources, we investigated the reciprocal genomewide transcriptional changes in both spider mite and tomato as a consequence of mite's adaptation to tomato. We transferred a genetically diverse mite population from bean to tomato where triplicated populations were allowed to propagate for 30 generations. Evolving populations greatly increased their reproductive performance on tomato relative to their progenitors when reared under identical conditions, indicative of genetic adaptation. Analysis of transcriptional changes associated with mite adaptation to tomato revealed two main components. First, adaptation resulted in a set of mite genes that were constitutively downregulated, independently of the host. These genes were mostly of an unknown function. Second, adapted mites mounted an altered transcriptional response that had greater amplitude of changes when re-exposed to tomato, relative to nonadapted mites. This gene set was enriched in genes encoding detoxifying enzymes and xenobiotic transporters. Besides the direct effects on mite gene expression, adaptation also indirectly affected the tomato transcriptional responses, which were attenuated upon feeding of adapted mites, relative to the induced responses by nonadapted mite feeding. Thus, constitutive downregulation and increased transcriptional plasticity of genes in a herbivore may play a central role in adaptation to host plants, leading to both a higher detoxification potential and reduced production of plant defence compounds. PMID:26211543

  16. Characterization of HIV-Specific CD4+T Cell Responses against Peptides Selected with Broad Population and Pathogen Coverage

    DEFF Research Database (Denmark)

    Buggert, Marcus; Norstrom, Melissa M.; Czarnecki, Chris;

    2012-01-01

    for the identification of HIV-specific CD4+ T cells targeting broadly reactive epitopes in populations with diverse ethnic background stems from the vast genomic variation of HIV and the diversity of the host cellular immune system. Here, we describe a novel epitope selection strategy, PopCover, that aims to resolve...... this challenge, and identify a set of potential HLA class II-restricted HIV epitopes that in concert will provide optimal viral and host coverage. Using this selection strategy, we identified 64 putative epitopes (peptides) located in the Gag, Nef, Env, Pol and Tat protein regions of HIV. In total, 73...... II-restricted epitopes. All together, selection strategies, such as PopCover, might with success be used for the evaluation of antigen-specific CD4+ T cell responses and design of future vaccines....

  17. A Diverse Family of Host-Defense Peptides (Piscidins) Exhibit Specialized Anti-Bacterial and Anti-Protozoal Activities in Fishes.

    Science.gov (United States)

    Salger, Scott A; Cassady, Katherine R; Reading, Benjamin J; Noga, Edward J

    2016-01-01

    Conventional antibiotics and other chemical-based drugs are currently one of the most common methods used to control disease-related mortality in animal agriculture. Use of the innate immune system to decrease disease related mortalities is a novel alternative to conventional drugs. One component of the innate immune system is the host-defense peptides, also known as antimicrobial peptides. Host-defense peptides are typically small, amphipathic, α-helical peptides with a broad-spectrum of action against viral, bacterial, fungal, and/or protozoal pathogens. Piscidins are host-defense peptides first discovered in the hybrid striped bass (white bass, Morone chrysops, x striped bass, M. saxatilis). In this paper we identify four new piscidin isoforms in the hybrid striped bass and describe their tissue distributions. We also determine the progenitor species of origin of each piscidin (orthology) and propose a revised nomenclature for this newly described piscidin family based on a three class system. The Class I piscidins (22 amino acids in length; striped bass and white bass piscidin 1 and piscidin 3) show broad-spectrum activity against bacteria and ciliated protozoans, while the Class III piscidins (55 amino acids in length; striped bass and white bass piscidin 6 and striped bass piscidin 7) primarily show anti-protozoal activity. The Class II piscidins (44-46 amino acids in length; striped bass and white bass piscidin 4 and white bass piscidin 5) have a level of activity against bacteria and protozoans intermediate to Classes I and III. Knowledge of piscidin function and activity may help in the future development of disease-resistant lines of striped bass and white bass that could be used to produce superior hybrids for aquaculture. PMID:27552222

  18. Host diversity begets parasite diversity: Bird final hosts and trematodes in snail intermediate hosts

    Science.gov (United States)

    Hechinger, R.F.; Lafferty, K.D.

    2005-01-01

    An unappreciated facet of biodiversity is that rich communities and high abundance may foster parasitism. For parasites that sequentially use different host species throughout complex life cycles, parasite diversity and abundance in 'downstream' hosts should logically increase with the diversity and abundance of 'upstream' hosts (which carry the preceding stages of parasites). Surprisingly, this logical assumption has little empirical support, especially regarding metazoan parasites. Few studies have attempted direct tests of this idea and most have lacked the appropriate scale of investigation. In two different studies, we used time-lapse videography to quantify birds at fine spatial scales, and then related bird communities to larval trematode communities in snail populations sampled at the same small spatial scales. Species richness, species heterogeneity and abundance of final host birds were positively correlated with species richness, species heterogeneity and abundance of trematodes in host snails. Such community-level interactions have rarely been demonstrated and have implications for community theory, epidemiological theory and ecosystem management. ?? 2005 The Royal Society.

  19. China’s Recycle copper Industry Holds Broad Prospects

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>According to China Aluminum Industry Report,in recent years China has introduced a host of incentive policies for solid waste recycling,which is part of the circular economy.On October 31,2011,the General Office of the State Council released the "Opinions on the

  20. An electron beam-heater with a broad-area plasma cathode

    International Nuclear Information System (INIS)

    An electron-beam heater with a broad-area plasma cathode was designed for thermal treatment of large surfaces in vacuum. Using the plasma electron source of broad cross-section beams instead of a hot-cathode gun generating thin scanning beams allows simultaneous heating all the surface as well as lengthening the service life and raising the reliability of the heater. A broad-area emitting plasma surface is produced in a special electrode cavity by injection into it, through a small hole, of charged particles from a reflex discharge with cold electrodes. Such a principle of design of the plasma cathode allows to obtain an electron beam of the required current density in the pressure range of 10-2 to 1 Pa. The heater can be operated with He, Ar, air and other gases. Using a multiaperture accelerating system comprising emitting and accelerating electrodes, an electron beam up to 150 mm in diameter with an energy up to 15 keV, a current up to 0.5 A, and a nonuniformity of the cross-sectional distribution of the current density not more than +- 6% on the area of 100 cm2 could be generated. The efficiency of the heater at the accelerating voltage of 11 to 13 kV equals to about 90%. (author)

  1. Association of host and microbial species diversity across spatial scales in desert rodent communities.

    Directory of Open Access Journals (Sweden)

    Yoni Gavish

    Full Text Available Relationships between host and microbial diversity have important ecological and applied implications. Theory predicts that these relationships will depend on the spatio-temporal scale of the analysis and the niche breadth of the organisms in question, but representative data on host-microbial community assemblage in nature is lacking. We employed a natural gradient of rodent species richness and quantified bacterial communities in rodent blood at several hierarchical spatial scales to test the hypothesis that associations between host and microbial species diversity will be positive in communities dominated by organisms with broad niches sampled at large scales. Following pyrosequencing of rodent blood samples, bacterial communities were found to be comprised primarily of broad niche lineages. These communities exhibited positive correlations between host diversity, microbial diversity and the likelihood for rare pathogens at the regional scale but not at finer scales. These findings demonstrate how microbial diversity is affected by host diversity at different spatial scales and suggest that the relationships between host diversity and overall disease risk are not always negative, as the dilution hypothesis predicts.

  2. Spectral Energy Distributions of SDSS Blazars

    Indian Academy of Sciences (India)

    H. Z. Li; L. E. Chen

    2014-09-01

    We compiled the radio, optical and X-ray data for SDSS sample, and presented broad band spectral index. The broad band energy distribution reveals that FSRQs and LBLs objects have similar spectral properties. However, HBLs have a separate distinct property. Even so, a unified scheme was also revealed from colour–colour diagram.

  3. Host Defence to Pulmonary Mycosis

    Directory of Open Access Journals (Sweden)

    Christopher H Mody

    1999-01-01

    Full Text Available OBJECTIVE: To provide a basic understanding of the mechanisms of host defense to pathogenic fungi. This will help physicians understand why some patients are predisposed to fungal infections and update basic scientists on how microbial immunology applies to fungal disease.

  4. AVTC Hosts TechnoCamp

    Science.gov (United States)

    Miner, Brenda

    2006-01-01

    The Area Vo-Tech Center (AVTC) in Russellville, Arkansas, recently hosted its first TechnoCamp to encourage enrollment based on the aptitude and interest level of the students enrolling in the various programs. The center currently offers student enrollment in auto technology, computer engineering, cosmetology, construction technology, drafting…

  5. Biosignatures of Pathogen and Host

    Energy Technology Data Exchange (ETDEWEB)

    Fitch, J P; Chromy, B A; Forde, C E; Garcia, E; Gardner, S N; Gu, P P; Kuczmarksi, T A; Melius, C F; McCutchen-Maloney, S L; Milanovich, F P; Motin, V L; Ott, L L; Quong, A A; Quong, J N; Rocco, J M; Slezak, T R; Sokhansanj, B A; Vitalis, E A; Zemla, A T; McCready, P M

    2002-08-27

    In information theory, a signature is characterized by the information content as well as noise statistics of the communication channel. Biosignatures have analogous properties. A biosignature can be associated with a particular attribute of a pathogen or a host. However, the signature may be lost in backgrounds of similar or even identical signals from other sources. In this paper, we highlight statistical and signal processing challenges associated with identifying good biosignatures for pathogens in host and other environments. In some cases it may be possible to identify useful signatures of pathogens through indirect but amplified signals from the host. Discovery of these signatures requires new approaches to modeling and data interpretation. For environmental biosignal collections, it is possible to use signal processing techniques from other applications (e.g., synthetic aperture radar) to track the natural progression of microbes over large areas. We also present a computer-assisted approach to identify unique nucleic-acid based microbial signatures. Finally, an understanding of host-pathogen interactions will result in better detectors as well as opportunities in vaccines and therapeutics.

  6. Host Event Based Network Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Jonathan Chugg

    2013-01-01

    The purpose of INL’s research on this project is to demonstrate the feasibility of a host event based network monitoring tool and the effects on host performance. Current host based network monitoring tools work on polling which can miss activity if it occurs between polls. Instead of polling, a tool could be developed that makes use of event APIs in the operating system to receive asynchronous notifications of network activity. Analysis and logging of these events will allow the tool to construct the complete real-time and historical network configuration of the host while the tool is running. This research focused on three major operating systems commonly used by SCADA systems: Linux, WindowsXP, and Windows7. Windows 7 offers two paths that have minimal impact on the system and should be seriously considered. First is the new Windows Event Logging API, and, second, Windows 7 offers the ALE API within WFP. Any future work should focus on these methods.

  7. Calcium Regulation of Hemorrhagic Fever Virus Budding: Mechanistic Implications for Host-Oriented Therapeutic Intervention.

    Directory of Open Access Journals (Sweden)

    Ziying Han

    2015-10-01

    Full Text Available Hemorrhagic fever viruses, including the filoviruses (Ebola and Marburg and arenaviruses (Lassa and Junín viruses, are serious human pathogens for which there are currently no FDA approved therapeutics or vaccines. Importantly, transmission of these viruses, and specifically late steps of budding, critically depend upon host cell machinery. Consequently, strategies which target these mechanisms represent potential targets for broad spectrum host oriented therapeutics. An important cellular signal implicated previously in EBOV budding is calcium. Indeed, host cell calcium signals are increasingly being recognized to play a role in steps of entry, replication, and transmission for a range of viruses, but if and how filoviruses and arenaviruses mobilize calcium and the precise stage of virus transmission regulated by calcium have not been defined. Here we demonstrate that expression of matrix proteins from both filoviruses and arenaviruses triggers an increase in host cytoplasmic Ca2+ concentration by a mechanism that requires host Orai1 channels. Furthermore, we demonstrate that Orai1 regulates both VLP and infectious filovirus and arenavirus production and spread. Notably, suppression of the protein that triggers Orai activation (Stromal Interaction Molecule 1, STIM1 and genetic inactivation or pharmacological blockade of Orai1 channels inhibits VLP and infectious virus egress. These findings are highly significant as they expand our understanding of host mechanisms that may broadly control enveloped RNA virus budding, and they establish Orai and STIM1 as novel targets for broad-spectrum host-oriented therapeutics to combat these emerging BSL-4 pathogens and potentially other enveloped RNA viruses that bud via similar mechanisms.

  8. Drivers of aggregation in a novel arboreal parasite: the influence of host size and infra-populations.

    Science.gov (United States)

    Yule, Kirsty J; Burns, Kevin C

    2015-02-01

    As a novel arboreal parasite, New Zealand's largest endemic moth, Aenetus virescens, is a biological oddity. With arguably the most unusual lepidopteran life history on earth, larvae grow to 100mm, spending ∼6 years as wood-boring parasites feeding on host tree phloem. Parasite fitness is a product of host suitability. Parasite discrimination between heterogeneous hosts in fragmented populations shapes parasite aggregation. We investigated whether A. virescens aggregation among hosts occurs randomly (target area effect), or if larvae select hosts based on host quality (ideal free distribution). Using long-term larval growth as an indicator of energy intake, we examined A. virescens aggregation in relation to host size and infra-population. Using a generalised linear model, the relationship between parasite intensity and host tree size was analysed. Reduced major axis regression was used to evaluate A. virescens growth after 1 year. Linear mixed-effects models inferred the influence of parasite infra-population on parasite growth, with host tree as a random factor. Results indicate parasite intensity scaled positively with host size. Furthermore, parasite growth remained consistent throughout ontogeny regardless of host size or parasite infra-population. Aenetus virescens aggregation among hosts violates the ideal free distribution hypothesis, occurring instead as a result of host size, supporting the target area effect.

  9. Planetary host stars: Evaluating uncertainties in ultra-cool model atmospheres

    CERN Document Server

    Bozhinova, I; Scholz, A

    2014-01-01

    M-dwarfs are discussed as promising targets for detecting planet at the lower mass end of the planetary mass distribution. An important step in this process is to accurately estimate the stellar parameters of the M-dwarf host star for which the results of stellar model atmosphere simulations are used. We present a comparison of the ATLAS9, MARCS, PHOENIX and Drift-PHOENIX model atmosphere families in the M-dwarf parameter space. We examine the differences in the (T$_{\\rm gas}$, p$_{\\rm gas}$)-structures, in synthetic photometric fluxes and in colour indices. We compiled the broad-band synthetic photometric fluxes for all available M-dwarf model atmospheres for the UKIRT WFCAM ZYJHK, 2MASS JHKs and Johnson UBVRI filters, and calculated related colour indices. We find that the synthetic colours in the IR wavelengths diverge by no more than 0.15 dex amongst all model families. For all bands considered, discrepancies in colour diminish for the higher T$_{\\rm eff}$-end of model atmosphere grids. We notice signific...

  10. Interpreting broad emission-line variations - II. Tensions between luminosity, characteristic size, and responsivity

    Science.gov (United States)

    Goad, M. R.; Korista, K. T.

    2015-11-01

    We investigate the variability behaviour of the broad H β emission-line to driving continuum variations in the best-studied AGN NGC 5548. For a particular choice of broad emission-line region (BLR) geometry, H β surface emissivity based on photoionization models, and using a scaled version of the 13-yr optical continuum light-curve as a proxy for the driving ionizing continuum, we explore several key factors that determine the broad emission-line luminosity L, characteristic size RRW, and variability amplitude (i.e. responsivity) η, as well as the interplay between them. For fixed boundary models which extend as far as the hot dust the predicted delays for H β are on average too long. However, the predicted variability amplitude of H β provides a remarkably good match to observations except during low-continuum states. We suggest that the continuum flux variations which drive the redistribution in H β surface emissivity F(r) do not on their own lead to large enough changes in RRW or ηeff. We thus investigate dust-bounded BLRs for which the location of the effective outer boundary is modulated by the continuum level and the dust-sublimation and dust-condensation time-scales. We find that in order to match the observed variability amplitude of broad H β in NGC 5548 a rather static outer boundary is preferred. Intriguingly, we show that the most effective way of reducing the H β delay, while preserving its responsivity and equivalent width, is to invoke a smaller value in the incident ionizing photon flux ΦH for a given ionizing source-cloud radial distance r, than is normally inferred from the observed UV continuum flux and typical models of the continuum spectral energy distribution.

  11. Mode of transmission, host switching, and escape from the Red Queen by viviparous gyrodactylids (Monogenoidea).

    Science.gov (United States)

    Boeger, Walter A; Kritsky, Delane C; Pie, Marcio R; Engers, Kerlen B

    2005-10-01

    Compared to other monogenoidean groups, viviparous gyrodactylids exhibit extraordinary species diversity and broad host range. It has been suggested that this evolutionary success is associated with a suite of morphological and life-history traits that include, in part, continuous transmission (i.e., ability to infect new hosts throughout the gyrodactylid life cycle). Experiments were conducted to explore the putative adaptive advantage of continuous transmission within viviparous gyrodactylids during colonization of new host resources. Differences in infrapopulation growth, such as abundance, prevalence, and duration of the infection, of Gyrodactylus anisopharynx on 3 species of fish--Corydoras paleatus and Corydoras ehrhardti (both natural hosts) as well as Corydoras schwartzi (a host not known to harbor G. anisopharynx)--held under isolated and grouped conditions were determined. Results showed that infrapopulations of G. anisopharynx on C. paleatus and C. schwartzi had higher growth when the parasite had the opportunity for host transfer (grouped hosts). Infrapopulations of G. anisopharynx on isolated and grouped C. ehrhardti showed an opposite trend, although differences in mean duration and maximum abundance were not statistically different. Results obtained from experiments with C. paleatus and C. schwartzi support the hypothesis that continuous transmission in viviparous gyrodactylids enhances colonization success, probably by allowing initial avoidance of Red Queen dynamics. The absence of statistical differences between infrapopulations on isolated and grouped C. ehrhardti suggests that parasite dynamics may be influenced by factors other than continuous transmission in this host. PMID:16419740

  12. Mini Review: Potential Applications of Non-host Resistance for Crop Improvement

    Science.gov (United States)

    Lee, Seonghee; Whitaker, Vance M.; Hutton, Samuel F.

    2016-01-01

    Plant breeding for disease resistance is crucial to sustain global crop production. For decades, plant breeders and researchers have extensively used host plant resistance genes (R-genes) to develop disease resistant cultivars. However, the general instability of R-genes in crop cultivars when challenged with diverse pathogen populations emphasizes the need for more stable means of resistance. Alternatively, non-host resistance is recognized as the most durable, broad-spectrum form of resistance against the majority of potential pathogens in plants and has gained great attention as an alternative target for managing resistance. While transgenic approaches have been utilized to transfer non-host resistance to host species, conventional breeding applications have been more elusive. Nevertheless, avenues for discovery and deployment of genetic loci for non-host resistance via hybridization are increasingly abundant, particularly when transferring genes among closely related species. In this mini review, we discuss current and developing applications of non-host resistance for crop improvement with a focus on the overlap between host and non-host mechanisms and the potential impacts of new technology. PMID:27462329

  13. Trophic ecology, behaviour and host population dynamics in Echinococcus multilocularis transmission.

    Science.gov (United States)

    Raoul, F; Hegglin, D; Giraudoux, P

    2015-10-30

    The life cycle of the cestode Echinococcus multilocularis primarily involves canids and small mammals (rodents, lagomorphs) as definitive and intermediate hosts, respectively. Several surveys have identified marked temporal and geographical variations at different scales in the parasite's prevalence in both types of hosts, suggesting variations in the biological and ecological factors that control transmission processes. The parasite transmission from intermediate to definitive hosts is determined by the predator-prey relationship, which theoretically depends on prey population dynamics and the complex dietary response of predators to varying densities of prey species and other food items. Parasite eggs are transmitted to intermediate hosts via carnivore faeces, whose distribution in the environment is driven by the defecating behaviour of final hosts. We reviewed field-based studies that address issues related to the trophic ecology and behaviour of definitive hosts, interactions between definitive and intermediate hosts, and E. multilocularis transmission both in wild and domestic animals in rural and urban environments. Two density-dependent mechanisms control the transmission dynamics in definitive hosts: one is based on the variations in the availability of intermediate hosts, and the other is based on the variations in the density of the definitive host and its faeces. Non-linearity and the direct and delayed responses of definitive host contamination in relation to intermediate host population variations were recorded. The dietary response of the red fox was shown to be complex when abundant alternative resources were available (anthropogenic food, multiple intermediate host prey species). Micro-local hotspots of parasite transmission to intermediate hosts in a landscape, as well as areas of higher risk for human contamination in village and urban settings, may be explained by the definitive hosts' activity patterns and defecation behaviour. PMID:26276578

  14. Quasar Cartography: from Black Hole to Broad Line Region Scales

    CERN Document Server

    Chelouche, Doron

    2013-01-01

    A generalized approach to reverberation mapping (RM) is presented, which is applicable to broad- and narrow-band photometric data, as well as to spectroscopic observations. It is based on multivariate correlation analysis techniques and, in its present implementation, is able to identify reverberating signals across the accretion disk and the broad line region (BLR) of active galactic nuclei (AGN). Statistical tests are defined to assess the significance of time-delay measurements using this approach, and the limitations of the adopted formalism are discussed. It is shown how additional constraints on some of the parameters of the problem may be incorporated into the analysis thereby leading to improved results. When applied to a sample of 14 Seyfert 1 galaxies having good-quality high-cadence photometric data, accretion disk scales and BLR sizes are simultaneously determined, on a case-by-case basis, in most objects. The BLR scales deduced here are in good agreement with the findings of independent spectrosc...

  15. Experimental evaluation of combustor concepts for burning broad property fuels

    Science.gov (United States)

    Kasper, J. M.; Ekstedt, E. E.; Dodds, W. J.; Shayeson, M. W.

    1980-01-01

    A baseline CF6-50 combustor and three advanced combustor designs were evaluated to determine the effects of combustor design on operational characteristics using broad property fuels. Three fuels were used in each test: Jet A, a broad property 13% hydrogen fuel, and a 12% hydrogen fuel blend. Testing was performed in a sector rig at true cruise and simulated takeoff conditions for the CF6-50 engine cycle. The advanced combustors (all double annular, lean dome designs) generally exhibited lower metal temperatures, exhaust emissions, and carbon buildup than the baseline CF6-50 combustor. The sensitivities of emissions and metal temperatures to fuel hydrogen content were also generally lower for the advanced designs. The most promising advanced design used premixing tubes in the main stage. This design was chosen for additional testing in which fuel/air ratio, reference velocity, and fuel flow split were varied.

  16. Flow characteristics at trapezoidal broad-crested side weir

    Directory of Open Access Journals (Sweden)

    Říha Jaromír

    2015-06-01

    Full Text Available Broad-crested side weirs have been the subject of numerous hydraulic studies; however, the flow field at the weir crest and in front of the weir in the approach channel still has not been fully described. Also, the discharge coefficient of broad-crested side weirs, whether slightly inclined towards the stream or lateral, still has yet to be clearly determined. Experimental research was carried out to describe the flow characteristics at low Froude numbers in the approach flow channel for various combinations of in- and overflow discharges. Three side weir types with different oblique angles were studied. Their flow characteristics and discharge coefficients were analyzed and assessed based on the results obtained from extensive measurements performed on a hydraulic model. The empirical relation between the angle of side weir obliqueness, Froude numbers in the up- and downstream channels, and the coefficient of obliqueness was derived.

  17. Shareholder, stakeholder-owner or broad stakeholder maximization

    DEFF Research Database (Denmark)

    Mygind, Niels

    2004-01-01

    With reference to the discussion about shareholder versus stakeholder maximization it is argued that the normal type of maximization is in fact stakeholder-owner maxi-mization. This means maximization of the sum of the value of the shares and stake-holder benefits belonging to the dominating...... stakeholder-owner. Maximization of shareholder value is a special case of owner-maximization, and only under quite re-strictive assumptions shareholder maximization is larger or equal to stakeholder-owner maximization. Broad stakeholder maximization is the sum of the returns to all stake-holders also...... including the shareholders of a company. Although it may be the ultimate goal for Corporate Social Responsibility to achieve this kind of maximization, broad stakeholder maximization is quite difficult to give a precise definition. There is no one-dimensional measure to add different stakeholder benefits...

  18. Broad Consent For Research With Biological Samples: Workshop Conclusions

    Science.gov (United States)

    Grady, Christine; Eckstein, Lisa; Berkman, Ben; Brock, Dan; Cook-Deegan, Robert; Fullerton, Stephanie M.; Greely, Hank; Hansson, Mats G.; Hull, Sara; Kim, Scott; Lo, Bernie; Pentz, Rebecca; Rodriguez, Laura; Weil, Carol; Wilfond, Benjamin S.; Wendler, David

    2016-01-01

    Different types of consent are used to obtain human biospecimens for future research. This variation has resulted in confusion regarding what research is permitted, inadvertent constraints on future research, and research proceeding without consent. The NIH Clinical Center’s Department of Bioethics held a workshop to consider the ethical acceptability of addressing these concerns by using broad consent for future research on stored biospecimens. Multiple bioethics scholars, who have written on these issues, discussed the reasons for consent, the range of consent strategies, gaps in our understanding, and concluded with a proposal for broad initial consent coupled with oversight and, when feasible, ongoing provision of information to donors. The manuscript describes areas of agreement as well as areas that need more research and dialogue. Given recent proposed changes to the Common Rule, and new guidance regarding storing and sharing data and samples, this is an important and timely topic. PMID:26305750

  19. Broad band polarimetric follow-up of Type IIP SN 2012aw

    CERN Document Server

    Kumar, Brajesh; Eswaraiah, C; Gorosabel, J

    2014-01-01

    We present the results based on R-band polarimetric follow-up observations of the nearby (~10 Mpc) Type II-plateau SN 2012aw. Starting from ~10 days after the SN explosion, these polarimetric observations cover ~90 days (during the plateau phase) and are distributed over 9 epochs. To characterize the Milky Way interstellar polarization (ISP_MW ), we have observed 14 field stars lying in a radius of 10 degree around the SN. We have also tried to subtract the host galaxy dust polarization component assuming that the dust properties in the host galaxy are similar to that observed for Galactic dust and the general magnetic field follow the large scale structure of the spiral arms of a galaxy. After correcting the IS_PMW , our analysis infer that SN 2012aw has maximum polarization of 0.85% +- 0.08% but polarization angle does not show much variation with a weighted mean value of ~138 degree. However, if both ISP_MW and host galaxy polarization (ISP_HG ) components are subtracted from the observed polarization valu...

  20. Oxygen consumption of rats with broad intestinal resection

    OpenAIRE

    Luz J.; Griggio M.A.; Fagundes D.J.; Araújo R.M.; Marcondes W.

    2000-01-01

    The study was performed to investigate possible alterations in oxygen consumption in an animal model with broad intestinal resection. Oxygen consumption and the thermal effect of a short meal were measured in rats subjected to short bowel syndrome. Four groups of rats were used. Group I was the control group, group II was sham operated, group III was submitted to 80% jejunum-ileum resection, and group IV was submitted to 80% jejunum-ileum resection with colon interposition. Ninety days after ...