141 research outputs found

    Vanadium (β-(Dimethylamino)ethyl)cyclopentadienyl Complexes with Diphenylacetylene Ligands

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    Reduction of the V(III) (β-(dimethylamino)ethyl)cyclopentadienyl dichloride complex [η5:η1-C5H4(CH2)2NMe2]VCl2(PMe3) with 1 equiv of Na/Hg yielded the V(II) dimer {[η5:η1-C5H4(CH2)2NMe2]V(µ-Cl)}2 (2). This compound reacted with diphenylacetylene in THF to give the V(II) alkyne adduct [η5:η1-C5H4(CH2)2NMe2]VCl(η2-PhC≡CPh). Further reduction of 2 with Mg in the presence of diphenylacetylene resulted in oxidative coupling of two diphenylacetylene groups to yield the diamagnetic, formally V(V), bent metallacyclopentatriene complex [η5:η1-C5H4(CH2)2NMe2]V(C4Ph4).

    Suplemento de difenil diselenuro inyectable en ovejas lecheras

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    Objective. The aim of this study was to evaluate the influence of subcutaneous supplementation with diphenyl diselenide ((PhSe)2) in dairy sheep infected with gastrointestinal nematodes on animal health and possible damage to environment when the feces of these animals will be used for fertilizing. Materials and methods. The experiment was performed using 16 primipara dairy sheep, that were divided into two groups: the group A as control and the group B supplemented with 3 µmol/kg of (PhSe)2 subcutaneously. Blood samples were used to determine the hepatic function, as well as the protein and lipid metabolism in animals. Feces were used to determine the number of helminths eggs per gram of feces (EPG), as well as used for ecotoxicology tests. Results. The (PhSe)2 supplementation not affected the helminths reproduction, since the EPG did not differ (p>0.05) between groups. Total protein and globulin levels increase (p<0.05) in supplemented animals, while the seric alanine aminotransferase (ALT) levels decrease (p<0.05) in the end of experimental design. Cholesterol levels increase (p<0.05) in the supplemented animals, while triglycerides, albumin and urea not differ between groups (p>0.05). The feces of supplemented sheep not interfered the springtails reproduction. Conclusions. At the administered dose, the (PhSe)2 is not able to control the parasitism, however, it did increase the globulins and cholesterol levels, that are important to immune response and for sheep reproduction, respectively. Also, the feces of supplemented animals with (PhSe)2 can be used as organic fertilizing, without negative impacts to environment.Objetivo. El objetivo de este estudio fue evaluar la influencia de la suplementación subcutánea con diselenuro de difenilo (PhSe)2 en ovejas lecheras infectadas con nematodos sobre la salud animal y posible daño al ambiente cuando las heces de estos animales se utilicen para fertilizar. Materiales y métodos. El experimento se realizó utilizando 16 ovejas lecheras, que se dividieron en dos grupos: el grupo A se usó como control y el grupo B se suplementó con 3 µmol/kg of (PhSe)2 vía subcutánea. Se utilizaron muestras de sangre para determinar la función hepática, así como el metabolismo de proteínas y lípidos en animales. Las heces se utilizaron para determinar el número de huevos por gramo de heces (EPG), así como para las pruebas de ecotoxicología. Resultados. La suplementación (PhSe)2 no afectó la reproducción de helmintos. Los niveles totales de proteína y globulina aumentan (p<0.05) en los animales suplementados, mientras que los niveles séricos de alanina aminotransferasa (ALT) disminuyen (p<0.05) al final del diseño experimental. Los niveles de colesterol aumentan (p<0.05) en los animales suplementados, mientras que los triglicéridos, la albúmina y la urea no difieren entre los grupos (p>0.05). Las heces de ovejas suplementadas no interferían en la reproducción de las colas de caballo. Conclusiones. A la dosis administrada, el (PhSe)2 no es capaz de controlar el parasitismo; sin embargo, aumenta los niveles de globulinas y colesterol, que son importantes para la respuesta inmune y para la reproducción, respectivamente. Las heces de animales suplementados pueden usarse como fertilizantes orgánicos, sin impactos negativos en el ambiente.

    Reconciling end-to-end and population concepts for marine ecosystems

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    Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 83 (2010): 99-103, doi:10.1016/j.jmarsys.2010.06.006.The inherent complexities in the structure and dynamics of marine food webs have led to two major simplifying concepts, a species-centric approach focused on physical processes driving the population dynamics of single species and a trophic-centric approach emphasizing energy flows through broad functional groups from nutrient input to fish production. Here we review the two approaches and discuss their advantages and limitations. We suggest that these concepts are complementary: their applications involve different time scales and distinct aspects of population and community resilience, but their integration is necessary for ecosystem-based managementWe acknowledge NOAA-CICOR award NA17RJ1233 (J.H. Steele) and NSF award OCE0217399 (D.J. Gifford)

    Construction kits or virtual worlds; management applications of E2E models

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    Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 109/110 (2013): 103-108, doi:10.1016/j.jmarsys.2011.10.016.We review briefly the diversity of modeling activity that comes under the rubric of end-to-end (E2E) models, but the focus of this paper – of joint concern to researchers and to managers - is on applications to management and decision making. The models and applications span a range from “construction kits” that identify particular management issues and use comparisons across ecosystems; to “virtual worlds” that immerse managers in the details of strategic evaluations for particular systems. The general conclusion is that “application” is not a straightforward transition from theory to practice but a complex interactive process.This review is based on the proceedings of a workshop, held at Woods Hole Oceanographic Institution, 19-22 April 2010, as part of CAMEO (Comparative Analysis of Marine Ecosystem Organization), a program supported jointly by NOAA (U.S. National Oceanic and Atmospheric Agency) and NSF (U.S. National Science Foundation)
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