55 research outputs found

    Genetic Structure and Demographic History Should Inform Conservation: Chinese Cobras Currently Treated as Homogenous Show Population Divergence

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    An understanding of population structure and genetic diversity is crucial for wildlife conservation and for determining the integrity of wildlife populations. The vulnerable Chinese cobra (Naja atra) has a distribution from the mouth of the Yangtze River down to northern Vietnam and Laos, within which several large mountain ranges and water bodies may influence population structure. We combined 12 microsatellite loci and 1117 bp of the mitochondrial cytochrome b gene to explore genetic structure and demographic history in this species, using 269 individuals from various localities in Mainland China and Vietnam. High levels of genetic variation were identified for both mtDNA and microsatellites. mtDNA data revealed two main (Vietnam + southern China + southwestern China; eastern + southeastern China) and one minor (comprising only two individuals from the westernmost site) clades. Microsatellite data divided the eastern + southeastern China clade further into two genetic clusters, which include individuals from the eastern and southeastern regions, respectively. The Luoxiao and Nanling Mountains may be important barriers affecting the diversification of lineages. In the haplotype network of cytchrome b, many haplotypes were represented within a “star” cluster and this and other tests suggest recent expansion. However, microsatellite analyses did not yield strong evidence for a recent bottleneck for any population or genetic cluster. The three main clusters identified here should be considered as independent management units for conservation purposes. The release of Chinese cobras into the wild should cease unless their origin can be determined, and this will avoid problems arising from unnatural homogenization

    Análise do impacto da implantação de sistemas ERP nas características organizacionais das empresas de construção civil

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    Uma das causas do insucesso do ERP nas empresas de construção civil é o fato da implantação desse sistema ser uma grande mudança organizacional. O objetivo desta pesquisa é identificar como a implementação do sistema ERP impacta na organização e nos processos gerencias das empresas de construção civil. Foi realizada uma survey em uma amostra de empresas construtoras brasileiras. Os dados foram coletados por meio de um questionário encaminhado por email a dois grupos de empresas: com e sem ERP implantado. A partir da análise estatística discriminante foi possível identificar as variáveis relacionadas ao nível de desenvolvimento dos processos de gestão e as características organizacionais que mais distinguem os dois grupos de empresas. Os resultados revelaram que a implantação do ERP impacta nas variáveis da maturidade organizacional nos seguintes aspectos: visão estratégica, relacionamento com cliente, gerenciamento de recursos humanos, gestão financeira e de TI

    Towards standard testing materials for high temperature solar receivers

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    This is an open access article under the CC BY-NC-ND licenseSolar thermal technology for the production on electricity is one of the current technological challenges. In concentrating solar power (CSP) plants, in order to achieve high power it is required to use a high operating temperature to reach high conversion efficiencies. The majority of today's commercial solar thermal power plants are based on the parabolic trough collector technology with operating temperature around 400 °C. However, the technology of solar tower is used in order to maximize the efficiency of the CSP plants. This technology reaches an operating temperature higher than 1000 °C and the development of high temperature receivers that work in this temperature ranges is still in its early stages. The fundamental problems observed are related to materials durability and reliability. The main objective of this paper has been to develop testing methods for solar receivers which guarantee their reliability and durability under demanding working conditions of high solar concentrating technology. Based on a revision of published or draft Standards, a qualification test methodology for durability tests has been developed.This paper has been funded by the project MIRASOL, ref ENE2012-39385-C03-01 (CENER) and ENE2012-39385-C03-03 (CSIC), within the framework “Subprograma de Proyectos de Investigación Fundamental no orientada (2012)”, MINECO (Spanish Government).Peer Reviewe

    ScienceDirect-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer review by the scientific conference committee of SolarPACES 2014 under responsibility of PSE AG Towards standard testing materials for high temperature solar receivers

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    Abstract Solar thermal technology for the production on electricity is one of the current technological challenges. In concentrating solar power (CSP) plants, in order to achieve high power it is required to use a high operating temperature to reach high conversion efficiencies. The majority of today's commercial solar thermal power plants are based on the parabolic trough collector technology with operating temperature around 400ºC. However, the technology of solar tower is used in order to maximize the efficiency of the CSP plants. This technology reaches an operating temperature higher than 1000 ºC and the development of high temperature receivers that work in this temperature ranges is still in its early stages. The fundamental problems observed are related to materials durability and reliability. The main objective of this paper has been to develop testing methods for solar receivers which guarantee their reliability and durability under demanding working conditions of high solar concentrating technology. Based on a revision of published or draft Standards, a qualification test methodology for durability tests has been developed

    Data from: Evolution and conservation on top of the world: Phylogeography of the Marbled Water Frog (Telmatobius marmoratus species complex; Anura, Telmatobiidae) in protected areas of Chile

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    The Andean Altiplano has served as a complex setting throughout its history, driving dynamic processes of diversification in several taxa. We investigated phylogeographic processes in the Telmatobius marmoratus species complex occurring in this region by studying the geographic patterns of genetic variability, genealogies, and historical migration, using the cytochrome b (cyt-b) gene as a marker. DNA sequences from Telmatobius gigas and Telmatobius culeus, Bolivian species with an uncertain taxonomic status, were also included. Additionally, we evaluated the phylogenetic diversity (PD) represented within Chilean protected areas and the complementary contribution from unprotected populations. Phylogenetic reconstructions from 148 cyt-b sequences revealed 4 main clades, one of which corresponded to T. culeus. T. gigas was part of T. marmoratus clade indicating paraphyletic relationships. Haplotypes from Chilean and Bolivian sites were not reciprocally monophyletic. Geographic distribution of lineages, spatial Bayesian analysis, and migration patterns indicated that T. marmoratus displays a weaker geographic structure than expected based on habitat distribution and physiological requirements. Demographic and statistical phylogeography analyses pointed out to a scenario of recent population expansion and high connectivity events of a more recent age than the post Last Glacial Maximum, probably associated to more humid events in Altiplano. PD of T. marmoratus populations within protected areas represents 55.6% of the total estimated PD. The unprotected populations that would contribute the most to PD are Caquena and Quebe (21%). Recent evolutionary processes and paleoclimatic changes, potentially driving shifts in habitat connectivity levels and population sizes, could explain the phylogeographic patterns recovered herein

    Simplified analysis of solar-weighted specular reflectance for mirrors with high specularity

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    The most relevant parameter to properly characterize solar mirrors is the solar-weighted near-specular reflectance. As this parameter cannot be directly measured with off-the-shelf instruments, a simplified procedure to be applied for highly specular solar mirrors is proposed in this paper. The approach, based on two criteria, was experimentally employed to check a wide variety of solar reflector materials. Only those mirrors with known high specularity passed the criteria, indicating that the proposed method is suitable
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