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31.
Jessica Zhang Sarah Palmer David Pimentel 《Environment, Development and Sustainability》2012,14(2):221-231
Several physical and chemical factors limit the production of biofuels, such as the complex process required for the conversion
of plant biomass into ethanol. For example, fossil energy inputs needed for the production of ethanol from corn is 1.59 liters
per liter of ethanol. One of the many factors limiting energy output from biomass is the extremely low fraction of sunlight
reaching a hectare that is captured by the plants. On average only about 0.1% of the sunlight is captured by green plants
per year. 相似文献
32.
David Pimentel 《Environment, Development and Sustainability》2012,14(2):151-152
33.
A limited battle involving the nuclear arsenals of India and Pakistan would have significant climatic impacts upon agricultural crop production in the United States; corn, soybeans, and winter wheat yields would be significantly reduced in the Corn Belt region of the US. The most severe impacts would occur during the second year after the modeled nuclear battle. 相似文献
34.
Noor Rehman Maria Inez G. de Miranda Simone M. L. Rosa Débora M. Pimentel Sônia M. B. Nachtigall Clara I. D. Bica 《Journal of Polymers and the Environment》2014,22(2):252-259
In this work cellulose was extracted from corn/maize straw (Zea mays) by means of an environmental-friendly multistep procedure involving alkaline treatment and a totally chlorine-free bleaching. This multistep procedure efficiently removed lignin and hemicelluloses. The pulp resulting from each step was characterized by attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR). The optimum pulping time (time of alkaline treatment) was determined by means of thermogravimetric analysis. The extracted cellulose is highly crystalline as verified by X-ray diffraction. The partial acid hydrolysis with sulfuric acid led to the isolation of cellulose whiskers in aqueous suspension as confirmed by light scattering and transmission electron microscopy. The depolarization ratio value of these nanocrystals is the same as that determined for cotton whiskers, showing that this ratio does not depend on the cellulose source. The maize whiskers are arranged laterally in bundles with average thickness around five times that of the crystallite. 相似文献
35.
Marcionília Fernandes Pimentel Évila Pinheiro Damasceno Paula Christine Jimenez Pedro Filipe Ribeiro Araújo Marcielly Freitas Bezerra Pollyana Cristina Vasconcelos de Morais Rivelino Martins Cavalcante Susana Loureiro Letícia Veras Costa Lotufo 《Environmental monitoring and assessment》2016,188(5):298
36.
37.
Catarina Vinagre Luís Narciso Marta Pimentel Henrique N. Cabral Maria J. Costa Rui Rosa 《Regional Environmental Change》2013,13(4):853-859
The Senegal sole, Solea senegalensis, is a species of flatfish that has several distinct cohorts of 0-group juveniles which use estuarine nurseries in summer and winter. The early cohort is more abundant and grows faster than the late cohort that stays in the nurseries during winter; however, climate warming may have an impact on the dynamics of this species’ juveniles. This study aimed to compare mortality, metabolic response and growth of S. senegalensis juveniles at different temperatures, reflecting present-day temperature (winter—12 °C; summer—24 °C) and future temperature (plus 3 °C) conditions, in estuarine nurseries in the southern European population. Mortality was low at 12 °C, being only 10 %, increasing to 30 % at 15 °C, 40 % at 24 °C and at 27 °C it hit 70 %. Metabolic rate increased steadily with increasing temperatures, yet it increased steeply from 24 to 27 °C. Thermal sensitivity was high for the temperature interval between 24 and 27 °C. Growth was very slow at 12 °C, at a rate of 0.03 mm day?1, increasing to 0.22 mm day?1 at 15 °C, and to 0.60 mm day?1, at 24 °C. However, at 27 °C growth rapidly declined to 0.12 mm day?1. Warming will be beneficial for the late cohort, resulting in a major increase in growth. However, the early cohort will not benefit from warming, due to high mortality and arrested growth, which clearly indicates that this species is under severe thermal stress at 27 °C. Thus, here we show, for the first time, that climate change may induce contrasting seasonal impacts on fish bio-ecology and physiology, namely in species with several cohorts over the course of the year. Phenotypic and/or genotypic plasticity may limit the impacts of climate change. 相似文献
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39.
An assessment was made of the energy efficiency, yield performance, and labor requirements for the production of corn, wheat, potatoes, and apples using organic (without synthetic chemical fertilizers and pesticides) and conventional farming technologies. Organic corn and wheat production was 29–70% more energy efficient than conventional production. However, conventional potato and apple production was 7–93% more energy efficient than organic production. For all four crops, the labor input per unit of yield was higher for organic systems compared with conventional production. 相似文献
40.