503 research outputs found

    Assessment of Safety impacts of Shoulder Paving in Illinois highways Using Empirical Bayesian and Cross-Sectional Analyses

    Get PDF
    La presente tesina documenta la calibración de funciones “de Seguridad” (Safety Performance Functions, SPF) para accidentes de tipo fatal, lesión y daños al vehículo para carreteras Interestatales, carriles múltiples y dos carriles ya sean rurales o urbanas, usando datos de segmentos de carreteras que no han recibido ningún tratamiento (siendo los tratamientos posibles repavimentado y/o pavimentado de arcenes) para el periodo 2000-2006. También se documenta la evaluación de impactos de seguridad de pavimentación de arcenes en la reducción de accidentes potencialmente afectados por el pavimentado de arcenes usando el análisis Bayesiano Empírico (EB) y el análisis de datos cruzados

    Assessment of Safety impacts of Shoulder Paving in Illinois highways Using Empirical Bayesian and Cross-Sectional Analyses

    Get PDF
    La presente tesina documenta la calibración de funciones “de Seguridad” (Safety Performance Functions, SPF) para accidentes de tipo fatal, lesión y daños al vehículo para carreteras Interestatales, carriles múltiples y dos carriles ya sean rurales o urbanas, usando datos de segmentos de carreteras que no han recibido ningún tratamiento (siendo los tratamientos posibles repavimentado y/o pavimentado de arcenes) para el periodo 2000-2006. También se documenta la evaluación de impactos de seguridad de pavimentación de arcenes en la reducción de accidentes potencialmente afectados por el pavimentado de arcenes usando el análisis Bayesiano Empírico (EB) y el análisis de datos cruzados

    Phylogenetic relationships of species of Raymunida (Decapoda: Galatheidae) based on morphology and mitochondrial cytochrome oxidase sequences, with the recognition of four new species

    Get PDF
    19 pages.-- RECEIVED: 10 April 2000, ACCEPTED: 8 November 2000.The species of the genus Raymunida from the Pacific and Indian oceans are revised using morphological characters and the mitochondrial cytochrome oxidase subunit I sequences. Four new species are described (R. confundens, R. dextralis, R. erythrina, and R. insulata), and the status of R. bellior and R. elegantissima are revised. The species of Raymunida can be identified by subtle morphological characters, which match differences in mitochondrial nucleotide sequences. Therefore, the sequence divergences confirm the specific and phylogenetic value of some morphological characters (e.g., length of the mesial spine on the basal antennal segment, length of the walking legs). Furthermore, they confirm the importance of the color pattern as a diagnostic character. The widespread species (R. elegantissima), known from the Philippines to Fiji, shows minimal divergence between specimens from different localities (maximum of 3 nucleotide differences or 0.2% mean divergence). The phylogenetic reconstruction agreed with the monophyletic condition of Raymunida and its differentiation with respect to the genus Munida (in which Raymunida species had previously been included) and Agononida.Peer reviewe

    Diversidad morfológica y molecular de los Unionidae (Mollusca, Bivalvia) de Portugal

    Get PDF
    Freshwater mussels from the family Unionidae are known to exhibit a high level of ecological phenotypic plasticity that is reflected in their shell shape. This variation has caused uncertainty on systematics and taxonomy of the group. Several naiad populations from nine river basins from Portugal were analyzed genetically, using two mitochondrial gene fragments (16SrRNA and Cytochrome Oxidase I) and morphologically, using ANOVA analyses of shell dimmensions. Molecular phylogenetic analyses were used to revise the systematics and to infer an evolutionary hypothesis for the family at the western-most Atlantic Iberian Peninsula. Genetic and morphological data were in agreement and supported the occurrence of 5 species in the region: Anodonta anatina, Anodonta cygnea, Potomida littoralis, Unio tumidiformis and Unio delphinus. The differentiation of all these species, except A. cygnea, is thought to have taken place during the isolation of the Iberian Peninsula and formation of the current river basins in the Tertiary. The possibility of A. cygnea being a relatively recent introduction is discussed. Basic morphometric measures of the shell proved to be useful to separate Unio species, but also seem to be strongly affected by environmental conditions. The high intra-specific morphologic variation was partially related to the species’ high level of phenotypic plasticity, but seems to have an important role in evolutionary processes.Las náyades de la familia Unionidae tienen gran plasticidad fenotípica, lo que se refleja en la forma de su concha. Esta variabilidad morfológica ha sido causa de gran confusión en la taxonomía y sistemática del grupo. Se han estudiado, genética y morfológicamente, numerosas poblaciones de náyades provenientes de nueve cuencas hidrográficas portuguesas. Para ello se han analizando dos fragmentos de genes mitocondriales (ARNr 16S y Citocromo Oxidasa I) así como diferentes variables morfológicas de la concha. Se han realizado además análisis filogenéticos para conocer la sistemática de la familia e inferir una hipótesis evolutiva de su distribución en el oeste de la península Ibérica. Los datos genéticos y morfológicos sugieren la existencia de cinco especies: Anodonta anatina, Anodonta cygnea, Potomida littoralis, Unio tumidiformis y Unio delphinus. La diferenciación de estas especies, con la excepción de A. cygnea, ha ocurrido durante el aislamiento de la península Ibérica y posterior formación de las actuales cuencas hidrográficas en el Terciario. Se discute la posibilidad de que la presencia de A. cygnea se deba a una introducción reciente. Los datos morfométricos analizados pueden ser útiles para separar las especies del género Unio, pero son también dependientes de las condiciones ambientales. La elevada variabilidad morfológica dentro de cada especie está relacionada con su plasticidad fenotípica, pero tiene a su vez un importante papel en el proceso evolutivo

    Effects of habitat transition on the evolutionary patterns of the microgastropod genus Pseudamnicola (Mollusca, Hydrobiidae)

    Get PDF
    Submitted: 8 October 2014, Accepted: 8 January 2015Molecular phylogenies of extant species are considered effective tools to infer mechanisms of speciation. Here, we benefit from this utility to investigate the evolutionary history of an organismal group linked to different aquatic ecosystems, the microgastropod genus Pseudamnicola (family Hydrobiidae). Previous studies have found around 45 species of the nominal subgenus P. (Pseudamnicola), most of them in coastal stream localities of several Mediterranean islands and mainland territories, whereas only 12 species of the other subgenus, P. (Corrosella), have been collected from springs and headwaters of mountainous regions of the Iberian Peninsula and south of France. As springs often act as isolated habitats affecting dispersion and constraining gene flow, we supposed that the temporal history and mode of diversification of species from both subgenera should differ and therefore be reflected in their phylogenetic patterns. To assess this hypothesis, we performed a molecular phylogeny based on mitochondrial and nuclear DNA sequences and later conducted an independent analysis to examine the potential effect of certain geographic and ecological variables in the genetic divergences of the subgenera. Additionally, we estimated the ancestral area of diversification of both groups. Published anatomical revisions and our molecular analyses suggest that the genus Pseudamnicola should be divided into three genera: the two previous subgenera plus a new one described here. As postulated, the evolution of the spring organisms was strongly related to habitat fragmentation and isolation, whereas dispersal followed by divergence seem to have been the most common speciation processes for euryhaline species inhabiting coastal streams and low river stages in which waters remain connected. On the contrary, rather than habitat fragmentation or dispersion, environmental conditions have played a larger role during the deep divergent split leading to the three genera.This work was funded by the grants of the MICINN project Fauna Ibérica X (CGL2010-22267-C07-01) and the JAE Predoctoral fellowship (JAEPre047) to D.D.Peer reviewe

    New sibling species and new occurrences of squat lobsters (Crustacea, Decapoda) from the western Indian Ocean

    Get PDF
    Este artículo contiene 61 páginas, 3 tablas, 14 figuras.Numerous specimens of squat lobsters belonging to the families Munididae, Munidopsidae and Eumunididae were collected during several cruises along the eastern coasts of Africa. The study of these specimens revealed the presence of 10 new species (one Eumunida Smith, 1883, eight Munida Leach, 1820 and one Munidopsis Whiteaves, 1874). We describe and illustrate these new species, providing some new data on occurrences and colour patterns for previously described taxa. We have also included molecular data from two mitochondrial markers (16S rRNA and COI) to support the taxonomic status of different species. Some deep-sea species show a clear increase in their geographic range distribution. Finally, a key to known species of the genus Munida from the western and central Indian Ocean is also presented.The MAINBAZA cruise, a joint project of MNHN (P. Bouchet principal investigator) and Instituto Español de Oceanografía (A. Ramos principal investigator), and the ATIMO VATAE and MIRIKY cruises formed part of a cluster of Mozambique- Madagascar expeditions (La Planète Revisitée/Our Planet Reviewed) funded by the Total, Prince Albert II of Monaco, and Stavros Niarchos foundations, and conducted by MNHN and Pro-Natura International. The figures of the carapaces were illustrated by J. Macpherson. Molecular data were obtained thanks to the partial support of a Spanish Ministry of Economy and Competitiveness project (ref. CTM 2014- 57949-R). EM is part of the research group 2014SGR-120 of the Generalitat de Catalunya.Peer reviewe

    Preliminary results from characterization of the Iberian Peninsula sturgeon based on analysis of the mtDNA cytochrome b

    Get PDF
    Historically, the Atlantic sturgeon Acipenser sturio L., 1758 was considered the only sturgeon species that inhabited rivers of the Iberian Peninsula. Nevertheless, in a recent paper, Garrido- Ramos et al. (1997) identified specimen EBD 8174 (museum collection of the Doñana Biological Station, Spain), from the Guadalquivir River, as the Adriatic sturgeon Acipenser naccarii Bonaparte, 1836, suggesting that both A. sturio and A. naccarii could be native to Spain. To test this theory, we compared partial mitochondrial cytochrome b (cyt b) gene sequences obtained from museum specimens of A. sturio that originated from the Iberian Peninsula, the Adriatic and the North Sea, as well as from live individuals of the Gironde River population in France. Specimens of A. naccarii and of the Siberian sturgeon Acipenser baerii Brandt, 1869 from fish farms were also included in the study. DNA from museum specimens was successfully amplified using the protocol of France and Kocher (1996) for DNA extraction from formalin-fixed and ethanol-preserved samples. Phylogenetic analysis was performed on partial cyt b gene sequences (over 402-bp and 245-bp). We identified specimen EBD 8174 as A. sturio, confirming the opinion that A. sturio is the only sturgeon species of the Iberian Peninsula. Further molecular analyses of museum specimens are needed for a description of the historical intraspecies genetic variation within A. sturio. This information is crucial for any future recovery plan for this species. Our comparison also showed interspecies sequence divergence ranging from 6.91% (A. sturio/A. naccarii) to 7.43% (A. sturio/A. baerii).Históricamente, el esturión atlántico Acipenser sturio L., 1758 ha sido considerado la única especie de esturión que vive en los ríos de la península Ibérica, siendo así demostrado por múltiples estudios morfológicos recientes. Sin embargo, un trabajo reciente identificó el ejemplar del río Guadalquivir EBD 8174 como Acipenser naccarii Bonaparte, 1836, sugiriendo que ambas especies de esturión podrían ser nativas de España. Para comprobar esta nueva teoría, se han analizado las secuencias del gen citocromo b mitocondrial en muestras de esturión atlántico preservadas en varios museos procedentes de la península Ibérica, el mar Adriático y el mar del Norte, así como material fresco del río Garona. Además, se han estudiado con fines comparativos varias muestras de A. naccarii y Acipenser baerii Brandt, 1869 procedentes de piscifactorías. Las muestras de museos fueron amplificadas con éxito usando un protocolo específico utilizado para material fijado en formol y preservado en alcohol. La muestra de esturión de España (EBD 8174) fue identificada como A. sturio. Este resulta do confirma que A. sturio es la única especie de esturión en la península Ibérica. De cualquier manera, antes de abordar los planes de recuperación, sería necesario realizar análisis moleculares complementarios para describir las posibles variaciones genéticas existentes entre poblaciones. La comparación de las secuencias de citocromo b de A. sturio con A. naccarii y A. baerii mostró valores de divergencia de 6,91% y 7,43% respectivamente.Instituto Español de Oceanografí
    corecore