62 research outputs found

    A Review Study on the Postharvest Decay Control of Fruit by <em>Trichoderma</em>

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    This chapter consists of an overview with the most relevant results about the efficacy of Trichoderma on postharvest disease control. The results of investigations demonstrate that this fungus can control several phytopathogens in different fruits. Postharvest losses represent a major problem in several countries. The constant application of fungicides not only at field but also at postharvest stage has led to microbial resistance cases, which make the control of these pathogens difficult. Biological control is a promising alternative to chemical fungicide applications. In this sense, an eco-friendly alternative and effective approach for controlling diseases is the use of microbial antagonists like Trichoderma, which have several mechanisms of action to stop disease development. A crucial treat in biological control is related to the maintenance of microbial viability and efficacy, that is why other technologies like their incorporation into edible films and coatings, nanotechnology, microbial mixtures, among others have been applied in combination with Trichoderma successfully. An enhancement in biocontrol activity is achieved when alternative systems are combined like GRAS substances, biopolymers, and other antagonists. Thus, Trichoderma is an eco-friendly alternative to threat postharvest diseases as an alternative to chemical treatments

    Distribución vertical de raíces en seis agroecosistemas en un acrisol de la sabana de Huimanguillo, Tabasco, México

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    Objective: We studied the density of length of thin roots (DLRD), less than 6 cm thick, in six agroecosystems that develop in an acid soil characteristic of the Sabana de Huimanguillo, Tabasco, Mexico, an “acahual” was taken as a reference and characterized floristically, identifying 33 species. Design / methodology / approach: A description of a soil profile was made, taking samples from each horizon to perform physical and chemical analyzes. The DRLD was estimated by the monolith method, considering four depths (0-10, 10-20, 20-30 and 30-40 cm), six samples were taken per agroecosystem. Results: The soil corresponded to a Chromic Acrisol (Loamic, Cutanic, Hyperdystric, Humic). The highest values of DRLD occurred in the first 20 cm, being 67, 69.1, 66.5, 81.4, 82.8 and 77.6% for pineapple, eucalyptus, acacia, rubber, grass and acahual, respectively. It was notorious that from 40 cm of depth the DLRD values decreased considerably in all agroecosystems. 33 plant species were identified Limitations of the study/implications: It is necessary to do more research of the DLRD at greater depth and in other savanna soils to establish clear differences of vertical exploration of the radical biomass. Findings / conclusions: The greatest development of DLRD occurs in the first 20 cm in the six agroecosystems, decreasing considerably according to depth. Grass presented the highest values of DLDR in general there were statistical differences between the first and the rest of the depths. No homogeneity of DLRD was observed in the arboreal agroecosystems in the studied depths.Objetivo: Estudiar la densidad de longitud de raíces delgadas (DLRD), de menos de 6 cm de grosor, en seis agroecosistemas que se desarrollan en un suelo ácido característico de la Sabana de Huimanguillo, Tabasco (México), se tomó como referencia y se caracterizó florísticamente un acahual. Diseño/metodología/aproximación: Se describió un perfil de suelo tomando muestras de cada horizonte para determinar sus características físicas y químicas. La DRLD se estimó mediante el método del monolito, considerando cuatro profundidades (0-10, 10-20, 20- 30 y 30-40 cm), se tomaron seis muestras por agroecosistema. Resultados: El suelo correspondió a un Chromic Acrisol (Loamic, Cutanic, Hyperdystric, Humic). Los valores más altos de DRL se presentaron en los primeros 20 cm, siendo 67, 69.1, 66.5, 81.4, 82.8 y 77.6% para piña, eucalipto, acacia, hule, pasto y acahual, respectivamente. Fue notorio que a partir de 40 cm de profundidad los valores de DLRD disminuyeron considerablemente en todos los agroecosistemas. Se identificaron 33 especies de plantas. Limitaciones del estudio/implicaciones: Es necesario hacer más investigación de la DLRD a mayor profundidad y en otros suelos de sabana para establecer con claridad diferencias de exploración vertical de la biomasa radical. Hallazgos/conclusiones: El mayor desarrollo de DLRD se da en los primeros 20 cm en los seis agroecosistemas, decreciendo considerablemente conforme a la profundidad. Pasto presentó los valores más altos de DLRD y de manera general hubo diferencias estadísticas entre la primera y el resto de las profundidades. No se observó homogeneidad de DLRD en los agroecosistemas arbóreos en las profundidades estudiadas

    Complications and treatment of dens in dente: case report

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    Dens in dente is an anomaly of dental development characterized by focal or multifocal invaginations of the enamel in the dental papilla before its mineralization, it can result in additional layers of enamel, cementum, dentin or pulp tissue, it is also known as invaginated tooth or invaginated odontoma. The clinical case of an 18-year-old female patient is presented, she comes to the clinic for referring halitosis and purulent exudate for 1 month, a clinical and radiographic examination of tooth 22 was performed, a radiopaque invagination line was observed that penetrates the portion radicular in the cervical third, wide radiolucent area in the apical third, sinuous course and purulent exudate. Root canal treatment was performed with a flexible rotary system and canal obturation with a lateral technique and vertical compaction, restored with resin

    Variable strength of forest stand attributes and weather conditions on the questing activity of Ixodes ricinus ticks over years in managed forests

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    Given the ever-increasing human impact through land use and climate change on the environment, we crucially need to achieve a better understanding of those factors that influence the questing activity of ixodid ticks, a major disease-transmitting vector in temperate forests. We investigated variation in the relative questing nymph densities of Ixodes ricinus in differently managed forest types for three years (2008–2010) in SW Germany by drag sampling. We used a hierarchical Bayesian modeling approach to examine the relative effects of habitat and weather and to consider possible nested structures of habitat and climate forces. The questing activity of nymphs was considerably larger in young forest successional stages of thicket compared with pole wood and timber stages. Questing nymph density increased markedly with milder winter temperatures. Generally, the relative strength of the various environmental forces on questing nymph density differed across years. In particular, winter temperature had a negative effect on tick activity across sites in 2008 in contrast to the overall effect of temperature across years. Our results suggest that forest management practices have important impacts on questing nymph density. Variable weather conditions, however, might override the effects of forest management practices on the fluctuations and dynamics of tick populations and activity over years, in particular, the preceding winter temperatures. Therefore, robust predictions and the detection of possible interactions and nested structures of habitat and climate forces can only be quantified through the collection of long-term data. Such data are particularly important with regard to future scenarios of forest management and climate warming

    A Broad Assessment of Factors Determining Culicoides imicola Abundance: Modelling the Present and Forecasting Its Future in Climate Change Scenarios

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    Bluetongue (BT) is still present in Europe and the introduction of new serotypes from endemic areas in the African continent is a possible threat. Culicoides imicola remains one of the most relevant BT vectors in Spain and research on the environmental determinants driving its life cycle is key to preventing and controlling BT. Our aim was to improve our understanding of the biotic and abiotic determinants of C. imicola by modelling its present abundance, studying the spatial pattern of predicted abundance in relation to BT outbreaks, and investigating how the predicted current distribution and abundance patterns might change under future (2011–2040) scenarios of climate change according to the Intergovernmental Panel on Climate Change. C. imicola abundance data from the bluetongue national surveillance programme were modelled with spatial, topoclimatic, host and soil factors. The influence of these factors was further assessed by variation partitioning procedures. The predicted abundance of C. imicola was also projected to a future period. Variation partitioning demonstrated that the pure effect of host and topoclimate factors explained a high percentage (>80%) of the variation. The pure effect of soil followed in importance in explaining the abundance of C. imicola. A close link was confirmed between C. imicola abundance and BT outbreaks. To the best of our knowledge, this study is the first to consider wild and domestic hosts in predictive modelling for an arthropod vector. The main findings regarding the near future show that there is no evidence to suggest that there will be an important increase in the distribution range of C. imicola; this contrasts with an expected increase in abundance in the areas where it is already present in mainland Spain. What may be expected regarding the future scenario for orbiviruses in mainland Spain, is that higher predicted C. imicola abundance may significantly change the rate of transmission of orbiviruses

    The tree that hides the forest: cryptic diversity and phylogenetic relationships in the Palaearctic vector Obsoletus/Scoticus Complex (Diptera: Ceratopogonidae) at the European level

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    Abstract Background Culicoides obsoletus is an abundant and widely distributed Holarctic biting midge species, involved in the transmission of bluetongue virus (BTV) and Schmallenberg virus (SBV) to wild and domestic ruminants. Females of this vector species are often reported jointly with two morphologically very close species, C. scoticus and C. montanus, forming the Obsoletus/Scoticus Complex. Recently, cryptic diversity within C. obsoletus was reported in geographically distant sites. Clear delineation of species and characterization of genetic variability is mandatory to revise their taxonomic status and assess the vector role of each taxonomic entity. Our objectives were to characterize and map the cryptic diversity within the Obsoletus/Scoticus Complex. Methods Portion of the cox1 mitochondrial gene of 3763 individuals belonging to the Obsoletus/Scoticus Complex was sequenced. Populations from 20 countries along a Palaearctic Mediterranean transect covering Scandinavia to Canary islands (North to South) and Canary islands to Turkey (West to East) were included. Genetic diversity based on cox1 barcoding was supported by 16S rDNA mitochondrial gene sequences and a gene coding for ribosomal 28S rDNA. Species delimitation using a multi-marker methodology was used to revise the current taxonomic scheme of the Obsoletus/Scoticus Complex. Results Our analysis showed the existence of three phylogenetic clades (C. obsoletus clade O2, C. obsoletus clade dark and one not yet named and identified) within C. obsoletus. These analyses also revealed two intra-specific clades within C. scoticus and raised questions about the taxonomic status of C. montanus. Conclusions To our knowledge, our study provides the first genetic characterization of the Obsoletus/Scoticus Complex on a large geographical scale and allows a revision of the current taxonomic classification for an important group of vector species of livestock viruses in the Palaearctic region

    La sequía de la península de Yucatán

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    La sequía es uno de los fenómenos naturales más difíciles de estudiar debido a que no se cuenta con una definición lo suficientemente clara ni con los recursos técnicos para poder predecirla. Es un problema que, en el mundo, se ha incrementado en las últimas décadas como consecuencia del cambio climático. En México, la sequía afecta a más personas que cualquier otra contingencia natural, por lo que se requiere estudiarla para poder prevenir y mitigar sus efectos. En la península de Yucatán (PY), zona privilegiada por tener un vasto manto acuífero, la sequía no se presenta de manera tan catastrófica como en otros estados de la república. La sequía produce pérdidas y bajo rendimiento de cultivos, cabezas de ganado y colmenas, disminución de la calidad de los productos, así como incremento en los costos de producción, lo que produce reducción en el ingreso de los productores. A nivel de los organismos operadores no se registra baja en la disponibilidad de agua durante la época de sequía y sólo se reporta su disminución para consumo humano en algunas localidades en donde el acuífero se encuentra muy profundo o la calidad natural del agua no es adecuada para consumo humano. Sin embargo, al depender la PY casi en su totalidad del acuífero para el abasto del agua, su disponibilidad podría disminuir súbitamente por problemas en la infraestructura del sistema operador o de contaminación (importante por la permeabilidad del sustrato geológico y porque no existen sistemas de drenaje y potabilización de agua suficientes)

    Lo glocal y el turismo. Nuevos paradigmas de interpretación.

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    El estudio del turismo se realiza desde múltiples escalas y enfoques, este libro aborda muchos temas que es necesario discutir desde diversas perspectivas; es el caso de la reflexión sobre la propia disciplina y sus conceptos, así como los asuntos específicos referidos al impacto territorial, los tipos de turismo, las cuestiones ambientales, el tema de la pobreza, la competitividad, las políticas públicas, el papel de las universidades, las áreas naturales protegidas, la sustentabilidad, la cultura, el desarrollo, la seguridad, todos temas centrales documentados y expuestos con originalidad y dominio del asunto. Lo multiescalar es básico para la comprensión del sistema turístico, sistema formado de procesos globales, regionales y locales. El eje de discusión del libro es lo glocal, esa interacción entre lo nacional y local con lo global

    Overview of recent TJ-II stellarator results

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    The main results obtained in the TJ-II stellarator in the last two years are reported. The most important topics investigated have been modelling and validation of impurity transport, validation of gyrokinetic simulations, turbulence characterisation, effect of magnetic configuration on transport, fuelling with pellet injection, fast particles and liquid metal plasma facing components. As regards impurity transport research, a number of working lines exploring several recently discovered effects have been developed: the effect of tangential drifts on stellarator neoclassical transport, the impurity flux driven by electric fields tangent to magnetic surfaces and attempts of experimental validation with Doppler reflectometry of the variation of the radial electric field on the flux surface. Concerning gyrokinetic simulations, two validation activities have been performed, the comparison with measurements of zonal flow relaxation in pellet-induced fast transients and the comparison with experimental poloidal variation of fluctuations amplitude. The impact of radial electric fields on turbulence spreading in the edge and scrape-off layer has been also experimentally characterized using a 2D Langmuir probe array. Another remarkable piece of work has been the investigation of the radial propagation of small temperature perturbations using transfer entropy. Research on the physics and modelling of plasma core fuelling with pellet and tracer-encapsulated solid-pellet injection has produced also relevant results. Neutral beam injection driven Alfvénic activity and its possible control by electron cyclotron current drive has been examined as well in TJ-II. Finally, recent results on alternative plasma facing components based on liquid metals are also presented. ISSN:0029-5515 ISSN:1741-432
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