Yield gap analysis and assessment of climate-induced yield trends of irrigated rice in selected provinces of the Philippines

This study describes a combined empirical/modeling approach to assess the possible impact of climate variability on rice production in the Philippines. We collated climate data of the last two decades (1985-2002) as well as yield statistics of six provinces of the Philippines, selected along a North-South gradient. Data from the climate information system of NASA were used as input parameters of the model ORYZA2000 to determine potential yields and, in the next steps, the yield gaps defined as the difference between potential and actual yields. Both simulated and actual yields of irrigated rice varied strongly between years. However, no climate-driven trends were apparent and the variability in actual yields showed no correlation with climatic parameters. The observed variation in simulated yields was attributable to seasonal variations in climate (dry/wet season) and to climatic differences between provinces and agro-ecological zones. The actual yield variation between provinces was not related to differences in the climatic yield potential but rather to soil and management factors. The resulting yield gap was largest in remote and infrastructurally disfavored provinces (low external input use) with a high production potential (high solar radiation and day-night temperature differences). In turn, the yield gap was lowest in central provinces with good market access but with a relatively low climatic yield potential. We conclude that neither long-term trends nor the variability of the climate can explain current rice yield trends and that agroecological, seasonal, and management effects are over-riding any possible climatic variations. On the other hand the lack of a climate-driven trend in the present situation may be superseded by ongoing climate change in the future.

Advanced Nuclear Energy Systems: Heat Transfer Issues and Trends

Almost 450 nuclear power plants are currently operating throughout the world and supplying about 17% of the world’s electricity. These plants perform safely, reliably, and have no free-release of byproducts to the environment. Given the current rate of growth in electricity demand and the ever growing concerns for the environment, the US consumer will favor energy sources that can satisfy the need for electricity and other energy-intensive products (1) on a sustainable basis with minimal environmental impact, (2) with enhanced reliability and safety and (3) competitive economics. Given that advances are made to fully apply the potential benefits of nuclear energy systems, the next generation of nuclear systems can provide a vital part of a long-term, diversified energy supply. The Department of Energy has begun research on such a new generation of nuclear energy systems that can be made available to the market by 2030 or earlier, and that can offer significant advances toward these challenging goals [1]. These future nuclear power systems will require advances in materials, reactor physics as well as heat transfer to realize their full potential. In this paper, a summary of these advanced nuclear power systems is presented along with a short synopsis of the important heat transfer issues. Given the nature of research and the dynamics of these conceptual designs, key aspects of the physics will be provided, with details left for the presentation.

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Es parla de la implantació dels estudis de Medicina a la ciutat de Girona

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Es parla dels quinze anys d’existència de la Universitat de Girona. Es fa memòria d’aquest període tancant el cercle d’una experiència inciada el 1991, quinze anys després, Engega s’atura en la implantació del Parc Científic i Tecnològic

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Es parla de la incidència de la MAT en l'entorn gironí, del Llibre Blanc de les Universitats Catalanes, de les investigacions sobre arqueologia que es fan al Sàhara i altres temes d'interès

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Editorial d'Engega sobre el paper de la revista com a territori neutral obert al debat

Novetats Editorial Documenta

Ressenya dels llibres: Cons i neocons. El rerefons filosòfic, de Joan Vergés Gifra (ed.); Les pintures rupestres prehistòriques del Zemmur (Sahara Occidental), de Joaquim Soler i Subils; Tratado de la cabrevación, de Jaume Tos i Urgellés; La patrimonialització de la materialitat etrusca de la Toscana

Editorial. Canviar per ser millors

Editorial d'Engega sobre l'Espai Europeu d'Ensenyament Superior