1,005 research outputs found

    Virulence of Spanish Phytophthora nicotianae isolates towards Capsicum annuum germplasm and pathogenicity towards Lycopersicum esculentum

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    The virulence of six northwestern Spanish Phytophthora nicotianae Breda de Haan isolates towards the pepper (Capsicum annuum) cultivars commonly used for the determination of P. capsici Leonian pathotype (SCM 334, PI201234 and Yolo Wonder), was similar to that of the latter oomycete but different to that of the German reference isolate P. nicotianae 411.87. When nine local C. annuum cultivars were inoculated with a P. nicotianae isolate of well known pathogenicity, the virulence recorded was significantly different to that recorded for P. capsici. Though the average level of resistance of the northwestern Spanish Capsicum germplasm to P. nicotianae was incomplete and weaker than that recorded for the SCM 334 and PI201234 cultivars, genotypes Co 12B and Co 3.25 showed high resistance to this oomycete. None of the six northwestern Spanish P. nicotianae isolates tested were pathogenic towards Lycopersicum esculentum cv. S. Pedro, unlike P. capsici, which produced clear collar and root rot in this host

    Neutrino mixing and masses in a left-right model with mirror fermions

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    In the framework of a left-right model containing mirror fermions with gauge group SU(3)CSU(2)LSU(2)RU(1)Y_{C} \otimes SU(2)_{L} \otimes SU(2)_{R} \otimes U(1)_{Y^\prime}, we estimate the neutrino masses, which are found to be consistent with their experimental bounds and hierarchy. We evaluate the decay rates of the Lepton Flavor Violation (LFV) processes μeγ\mu \rightarrow e \gamma, τμγ\tau \rightarrow \mu \gamma and τeγ\tau \rightarrow e\gamma. We obtain upper limits for the flavor-changing branching ratios in agreement with their present experimental bounds. We also estimate the decay rates of heavy Majorana neutrinos in the channels NW±lN \rightarrow W^{\pm} l^{\mp}, NZνlN \rightarrow Z \nu_{l} and NHνlN \rightarrow H \nu_{l}, which are roughly equal for large values of the heavy neutrino mass. Starting from the most general Majorana neutrino mass matrix, the smallness of active neutrino masses turns out from the interplay of the hierarchy of the involved scales and the double application of seesaw mechanism. An appropriate parameterization on the structure of the neutrino mass matrix imposing a symmetric mixing of electron neutrino with muon and tau neutrinos leads to Tri-bimaximal mixing matrix for light neutrinos.Comment: Accepted by European Physical Journal

    Coping with feed scarcity in smallholder livestock systems in developing countries

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    Neutrino masses and mixing parameters in a left-right model with mirror fermions

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    In this work we consider a left-right model containing mirror fermions with gauge group SU(3)CSU(2)LSU(2)RU(1)Y_{C} \otimes SU(2)_{L} \otimes SU(2)_{R} \otimes U(1)_{Y^\prime}. The model has several free parameters which here we have calculated by using the recent values for the squared-neutrino mass differences. Lower bound for the mirror vacuum expectation value helped us to obtain crude estimations for some of these parameters. Also we estimate the order of magnitude of the masses of the standard and mirror neutrinos.Comment: 13 pages, version submitted to European Physical Journal

    Protection of Rabbits against Rabbit Hemorrhagic Disease Virus by Immunization with the VP60 Protein Expressed in Plants with a Potyvirus-Based Vector

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    AbstractA new plum pox potyvirus (PPV)-based vector has been constructed for the expression of full-length individual foreign proteins. The foreign sequences are cloned between the NIb replicase and capsid protein (CP) cistrons. The heterologous protein is split from the rest of the potyviral polyprotein by cleavage at the site that originally separated the NIb and CP proteins and at an additional NIa protease recognition site engineered at its amino-terminal end. This vector (PPV–NK) has been used to clone different genes, engendering stable chimeras with practical applications. We have constructed a chimera expressing high levels of jellyfish green fluorescent protein, which can be very useful for the study of PPV molecular biology. The VP60 structural protein of rabbit hemorrhagic disease virus (RHDV) was also successfully expressed by making use of the PPV–NK vector. Inoculation of extracts from VP60-expressing plants induced a remarkable immune response against RHDV in rabbits, its natural host. Moreover, these animals were protected against a lethal challenge with RHDV

    The communicative management of large companies in Spain: structure, resources and main challenges of their managers

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    This article studies the communicative structures of the main companies in Spain. Based on the fact that these organisations have significant economic and human resources, the structure of their communication areas is analysed, as well as the specific training of their top managers. In addition, the article will outline the main concerns that these organisational structures have with regard to the day-to-day management of business communication (transparency, reputation, identity, etc.). To do this, the object of the study is made up of the main companies in the Spanish continuous market, some of them included in the Ibex 35 in 2018. This population has been selected because it has the greatest impact on the national economy and is susceptible to greater information transparency.El presente artículo reflexiona sobre las estructuras comunicativas de las principales empresas españolas. Partiendo de la base de que estas organizaciones tienen importantes recursos económicos y humanos, se analiza la organización de sus áreas de comunicación, las prácticas que llevan a cabo y la formación específica de sus máximos responsables. Además, se detallan las principales preocupaciones y retos de esos departamentos de comunicación en el presente y el futuro inmediato (transparencia, reputación, identidad, etc.). El objeto de estudio lo constituyen las empresas españolas con mayor volumen de facturación, incluyendo las del Ibex 35 en 2018, por ser las de mayor impacto en la economía nacional, además de susceptibles de una mayor transparencia informativa

    Turbulencia empresarial en Colombia : sector de seguros

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    En el año 2010, la Facultad de Administración de la Universidad del Rosario puso en marcha un proyecto de investigación donde se exploraba el fenómeno de la turbulencia empresarial. En este momento han sido publicados más de 15 documentos donde se realiza la descripción de lo ocurrido en igual número de sectores. En este número se realiza un análisis del sector asegurador, actividad empresarial que contribuye de manera significativa a la economía del país. El trabajo ha sido realizado de manera conjunta por los profesores Natalia Malaver y Hugo Rivera de la asignatura Estrategia de empresa I, con estudiantes del pregrado de la Facultad, quienes se motivaron por encontrar respuestas a la forma como algunas empresas del sector enfrentan la turbulencia sectorial. La estructura del documento incluye una breve descripción del sector; luego un análisis de la turbulencia, y un estudio sectorial realizado aplicando la metodología del Análisis Estructural de Sectores Estratégicos (AESE) desarrollada por el grupo de investigación en perdurabilidad empresarial de la Facultad de Aministración de la Universidad del Rosario
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