180 research outputs found

    An Overview of the Rotational Behavior of Metal--Poor Stars

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    The present paper describes the behavior of the rotational velocity in metal--poor stars ([Fe/H]<-0.5 dex) in different evolutionary stages, based on Vsini values from the literature. Our sample is comprised of stars in the field and some Galactic globular clusters, including stars on the main sequence, the red giant branch (RGB), and the horizontal branch (HB). The metal--poor stars are, mainly, slow rotators, and their Vsini distribution along the HR diagram is quite homogeneous. Nevertheless, a few moderate to high values of Vsini are found in stars located on the main sequence and on the HB. We show that the overall distribution of Vsini values is basically independent of metallicity for the stars in our sample. In particular, the fast-rotating main sequence stars in our sample present similar rotation rates as their metal-rich counterparts, suggesting that some of them may actually be fairly young, in spite of their low metallicity, or else that at least some of them would be better classified as blue straggler stars. We do not find significant evidence of evolution in Vsini values as a function of position on the RGB; in particular, we do not confirm previous suggestions that stars close to the RGB tip rotate faster than their less evolved counterparts. While the presence of fast rotators among moderately cool blue HB stars has been suggested to be due to angular momentum transport from a stellar core that has retained significant angular momentum during its prior evolution, we find that any such transport mechanisms must likely operate very fast as the star arrives on the zero-age HB (ZAHB), since we do not find a link between evolution off the ZAHB and Vsini values. We present an extensive tabulation of all quantities discussed in this paper, including rotation velocities, temperatures, gravitieComment: 22 pages, 10 figure

    InfluĂȘncia de espĂ©cies perenes sobre os grupos funcionais da fauna do solo em sistemas agrossilviculturais na AmazĂŽnia Central.

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    O objetivo do trabalho foi avaliar a influĂȘncia de algumas espĂ©cies perenes (palmeiras, frutĂ­feras e madeireiras) sobre a diversidade, abundĂąncia, e distribuição vertical dos grupos funcionais de fauna do solo, em comparação com Vismia cayennensis, espĂ©cie representativa da vegetação secundĂĄria

    The genetic ancestry of American Creole cattle inferred from uniparental and autosomal genetic markers

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    Cattle imported from the Iberian Peninsula spread throughout America in the early years of discovery and colonization to originate Creole breeds, which adapted to a wide diversity of environments and later received influences from other origins, including zebu cattle in more recent years. We analyzed uniparental genetic markers and autosomal microsatellites in DNA samples from 114 cattle breeds distributed worldwide, including 40 Creole breeds representing the whole American continent, and samples from the Iberian Peninsula, British islands, Continental Europe, Africa and American zebu. We show that Creole breeds differ considerably from each other, and most have their own identity or group with others from neighboring regions. Results with mtDNA indicate that T1c-lineages are rare in Iberia but common in Africa and are well represented in Creoles from Brazil and Colombia, lending support to a direct African influence on Creoles. This is reinforced by the sharing of a unique Y-haplotype between cattle from Mozambique and Creoles from Argentina. Autosomal microsatellites indicate that Creoles occupy an intermediate position between African and European breeds, and some Creoles show a clear Iberian signature. Our results confirm the mixed ancestry of American Creole cattle and the role that African cattle have played in their development.Fil: Ginja, Catarina. Universidad de Porto. Facultad de CiĂȘncias. Centro de Investigação em Biodiversidade e Recursos GenĂ©ticos; PortugalFil: Gama, Luis Telo. Universidade de Lisboa. Faculdade de Medicina Veterinaria; PortugalFil: CortĂ©s, Oscar. Universidad Complutense de Madrid; EspañaFil: Martin Burriel, Inmaculada. Universidad de Zaragoza; EspañaFil: Vega Pla, Jose Luis. Servicio de CrĂ­a Caballar de las Fuerzas Armadas. Laboratorio de InvestigaciĂłn Aplicada; EspañaFil: Penedo, Cecilia. University of California; Estados UnidosFil: Sponenberg, Phil. Virginia-Maryland Regional College of Veterinary Medicine; Estados UnidosFil: Cañón Ferreras, Francisco Javier. Universidad Complutense de Madrid; EspañaFil: Sanz, Arianne. Universidad de Zaragoza; EspañaFil: Egito, Andrea Alves do. Embrapa Gado de Corte; BrasilFil: Alvares, Luz Angela. Universidad Nacional de Colombia; ColombiaFil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico CONICET- La Plata. Instituto de GenĂ©tica Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de GenĂ©tica Veterinaria; ArgentinaFil: Agha, Saif. Ain Shams University. Faculty of Agriculture, Animal Production Department; EgiptoFil: Rogberg Muñoz, Andres. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico CONICET- La Plata. Instituto de GenĂ©tica Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de GenĂ©tica Veterinaria; ArgentinaFil: Cassiano Lara, Maria Aparecida. Centro de GenĂ©tica e Reprodução. Instituto de Zootecnia; BrasilFil: Delgado, Juan Vicente. Universidad de CĂłrdoba; EspañaFil: Martinez, Amparo. Universidad de CĂłrdoba; Españ

    The genetic ancestry of American Creole cattle inferred from uniparental and autosomal genetic markers

    Get PDF
    Cattle imported from the Iberian Peninsula spread throughout America in the early years of discovery and colonization to originate Creole breeds, which adapted to a wide diversity of environments and later received influences from other origins, including zebu cattle in more recent years. We analyzed uniparental genetic markers and autosomal microsatellites in DNA samples from 114 cattle breeds distributed worldwide, including 40 Creole breeds representing the whole American continent, and samples from the Iberian Peninsula, British islands, Continental Europe, Africa and American zebu. We show that Creole breeds differ considerably from each other, and most have their own identity or group with others from neighboring regions. Results with mtDNA indicate that T1c-lineages are rare in Iberia but common in Africa and are well represented in Creoles from Brazil and Colombia, lending support to a direct African influence on Creoles. This is reinforced by the sharing of a unique Y-haplotype between cattle from Mozambique and Creoles from Argentina. Autosomal microsatellites indicate that Creoles occupy an intermediate position between African and European breeds, and some Creoles show a clear Iberian signature. Our results confirm the mixed ancestry of American Creole cattle and the role that African cattle have played in their development.Fil: Ginja, Catarina. Universidad de Porto. Facultad de CiĂȘncias. Centro de Investigação em Biodiversidade e Recursos GenĂ©ticos; PortugalFil: Gama, Luis Telo. Universidade de Lisboa. Faculdade de Medicina Veterinaria; PortugalFil: CortĂ©s, Oscar. Universidad Complutense de Madrid; EspañaFil: Martin Burriel, Inmaculada. Universidad de Zaragoza; EspañaFil: Vega Pla, Jose Luis. Servicio de CrĂ­a Caballar de las Fuerzas Armadas. Laboratorio de InvestigaciĂłn Aplicada; EspañaFil: Penedo, Cecilia. University of California; Estados UnidosFil: Sponenberg, Phil. Virginia-Maryland Regional College of Veterinary Medicine; Estados UnidosFil: Cañón Ferreras, Francisco Javier. Universidad Complutense de Madrid; EspañaFil: Sanz, Arianne. Universidad de Zaragoza; EspañaFil: Egito, Andrea Alves do. Embrapa Gado de Corte; BrasilFil: Alvares, Luz Angela. Universidad Nacional de Colombia; ColombiaFil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico CONICET- La Plata. Instituto de GenĂ©tica Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de GenĂ©tica Veterinaria; ArgentinaFil: Agha, Saif. Ain Shams University. Faculty of Agriculture, Animal Production Department; EgiptoFil: Rogberg Muñoz, Andres. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico CONICET- La Plata. Instituto de GenĂ©tica Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de GenĂ©tica Veterinaria; ArgentinaFil: Cassiano Lara, Maria Aparecida. Centro de GenĂ©tica e Reprodução. Instituto de Zootecnia; BrasilFil: Delgado, Juan Vicente. Universidad de CĂłrdoba; EspañaFil: Martinez, Amparo. Universidad de CĂłrdoba; Españ

    Segmenting visitors of cultural events: The case of Christmas Market

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    Market segmentation in tourism makes use of sets of powerful analytical tools for the sake of planning and managing demand-oriented policies. This paper contributes to this strand of literature by segmenting tourists visiting a cultural event. We utilize the Bagged Clustering method, a combination of traditional partitioning and hierarchical techniques, which is proven to be more effective. An ad hoc survey was conducted in 2011 among the Italian visitors of the Christmas Market in Merano, Northern Italy. A total of 802 questionnaires were collected. In discussing the results, marketing and managerial implications are stressed for both policymakers and local organizers. © 2014 Elsevier Ltd. All rights reserved

    Introgressive hybridization in a Spiny-Tailed Iguana, Ctenosaura pectinata, and its implications for taxonomy and conservation

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    Introgression, the transmission of genetic material of one taxon into another through hybridization, can have various evolutionary outcomes. Previous studies have detected signs of introgression between western populations of the Mexican endemic and threatened spiny-tailed iguana, Ctenosaura pectinata. However, the extent of this phenomenon along the geographic distribution of the species is unknown. Here, we use multilocus data together with detailed geographic sampling to (1) define genotypic clusters within C. pectinata; (2) evaluate geographic concordance between maternally and biparentally inherited markers; (3) examine levels of introgression between genotypic clusters, and (4) suggest taxonomic modifications in light of this information. Applying clustering methods to genotypes of 341 individuals from 49 localities of C. pectinata and the closely related C. acanthura, we inferred the existence of five genotypic clusters. Contact zones between genotypic clusters with signatures of interbreeding were detected, showing different levels of geographic discordance with mtDNA lineages. In northern localities, mtDNA and microsatellites exhibit concordant distributions, supporting the resurrection of C. brachylopha. Similar concordance is observed along the distribution of C. acanthura, confirming its unique taxonomic identity. Genetic and geographic concordance is also observed for populations within southwestern Mexico, where the recognition of a new species awaits in depth taxonomic revision. In contrast, in western localities a striking pattern of discordance was detected where up to six mtDNA lineages co-occur with only two genotypic clusters. Given that the type specimen originated from this area, we suggest that individuals from western Mexico keep the name C. pectinata. Our results have profound implications for conservation, management, and forensics of Mexican iguanas

    Adaptation to flood risk - results of international paired flood event studies

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    As flood impacts are increasing in large parts of the world, understanding the primary drivers of changes in risk is essential for effective adaptation. To gain more knowledge on the basis of empirical case studies, we analyze eight paired floods, that is, consecutive flood events that occurred in the same region, with the second flood causing significantly lower damage. These success stories of risk reduction were selected across different socioeconomic and hydro‐climatic contexts. The potential of societies to adapt is uncovered by describing triggered societal changes, as well as formal measures and spontaneous processes that reduced flood risk. This novel approach has the potential to build the basis for an international data collection and analysis effort to better understand and attribute changes in risk due to hydrological extremes in the framework of the IAHSs Panta Rhei initiative. Across all case studies, we find that lower damage caused by the second event was mainly due to significant reductions in vulnerability, for example, via raised risk awareness, preparedness, and improvements of organizational emergency management. Thus, vulnerability reduction plays an essential role for successful adaptation. Our work shows that there is a high potential to adapt, but there remains the challenge to stimulate measures that reduce vulnerability and risk in periods in which extreme events do not occur
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