2,835 research outputs found

    Potential Response of Soil-Borne Fungal Pathogens Affecting Crops to a Scenario of Climate Change in Europe

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    A study was carried out on the potential response of soil-borne pathogens causing crop yield losses under a climate change scenario in Europe. A controlled chamber set of experiments was carried out to quantify pathogen response to temperature using pure colonies of three soil-borne fungi, representative of low (Fusarium nivale), medium-high (Athelia rolfsii) and high (Macrophomina phaseolina) temperature requirements. A generic model to simulate fungal growth response to temperature based on these experiments was developed and linked to a soil temperature model component, and to components to simulate soil water content accounting for crop water uptake of potential hosts. Pathogens relative growth was simulated over Europe using the IPCC A1B emission scenario as realization of the Hadley-CM3 global climate model, available from the European Commission and processed for use with biophysical models. The simulations resulting from using the time span centred on 2030 were compared to the baseline, centred on the year 2000, using a sample of 30 years of daily weather. The general trend of soil-borne pathogens response to the scenario of climate change is a relative increase in growth in colder areas of Europe, as a function of their temperature requirements. Projections of F. nivale in the future indicate a relative increase of this winter pathogen of wheat in Northern European countries. A. rolfsii and M. phaseolina, two soil-borne pathogens typical of warmer agricultural areas, could find more favourable conditions in areas of the Central Europe, but they differentiated in Southern Europe where A. rolfsii resulted affected by summer soil temperatures above optimum

    Short-Circuit Protection Schemes for LVDC Microgrids Based on the Combination of Hybrid Circuit Breakers and Mechanical Breakers

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    In recent years, low-voltage direct current (LVDC) microgrids are becoming more attractive because they represent a solution to integrate renewable sources, storage, and electronic loads bringing some advantages in comparison with traditional AC grids. However, the protection of such a network involves many challenges, especially in the case of LVDC microgrids with more than one feeder and multiple energy sources. Indeed, the traditional protection breakers used for an AC grid cannot isolate the faults and protect the components of a DC grid, while the use of solid-state circuit breakers increases energy losses. This paper deals with the analysis and design of the protection schemes for LVDC microgrids through the combination of mechanical circuit breakers and hybrid circuit breakers. This solution has the advantage of energy loss reduction but introduces further issues due to the slow transition times of the mechanical circuit breakers. Thus, a completely decentralized control system capable of overcoming the fast fault-clearing time, cost-effectiveness, and selectivity issues is designed to protect from pole-to-pole faults. The proposed control strategy is compared with a centralized protection scheme available in the literature through numerical simulation. The two algorithms show similar performances, with a mean voltage dip duration of less than 30 ms and a maximum voltage dip duration of about 100 ms in the most severe fault condition, but the proposed solution is more reliable and flexible since it does not depend on the communication system

    Rendimiento de dos lĂ­neas comerciales de pollos parrilleros

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    p.105-109Se comparó la tasa de crecimiento de los cortes de interés comercial en pollos parrilleros de las líneas Arbor Acres y Cobb 500, faenados entre los 35 y 56 días de edad. La tasa de crecimiento de la carcasa eviscerada se relacionó con el peso de faena, mientras que el crecimiento de la grasa abdominal, pechuga, muslos, patas, piernas y alas con el peso de la carcasa eviscerada. Todos los cortes se evaluaron con músculo, hueso y piel. En las hembras, el ritmo de crecimiento de las características estudiadas, no presentó diferencias significativas (Pmenor a 0,05) debidas a la línea comercial. En los machos, no se observaron diferencias significativas (P mayor a 0,05) en el crecimiento de la pechuga, alas y grasa abdominal, en cambio presentaron diferencias el ritmo de crecimiento de la carcasa (Pmenor a 0,01), de los muslos (P menor a 0,05), de las patas (P menor a 0,05) y de las piernas (P menor a 0,01), siendo superior en la línea Cobb 500 que en Arbor Acres

    Single Nucleotide Polymorphism discovery and genotyping within the chicken Tapasin gene

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    Tapasin is one of the specific accessory molecules for the assembly of MHC class I molecules inside the Endoplasmic Reticulum (ER) (Antoniou et al., 2003). Mammalian tapasin is a 48 kDa transmembrane chaperone-protein (Sadasivan et al., 1996), and is member of the immunoglobulin superfamily (Ortmann et al., 1997)

    Economic and environmental sustainability dimensions of a fashion supply chain: A quantitative model

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    Paper aim: The paper presents a model to assess the economic and the environmental sustainability dimensions of a fashion supply chain and tests it on a company. Originality: The gap intended to fill is the lack of models in this context having this purpose, and, in general, the necessity to develop models and metrics allowing to quantitatively assess the economic and environmental dimensions of supply chains. Research method: The fashion supply chain has been divided into five processes. Hence, an analytic model was developed by considering the total costs incurring in each process (economic evaluation), and the annual kilograms of CO2 emitted (environmental perspective). The model was then applied to a case study. Data was obtained from interviews with the management. Main findings: Results show that from the economic perspective supply impacts the most, while from the environmental one the most polluting activity is production. Implications for theory and practice: The model is easy to apply and to understand and allows to identify the activities in the supply chain where the majority of costs/emissions are generated. It is therefore expected to be useful for undertaking operational decisions aimed at decreasing the economic or environmental impact of a fashion supply chain
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