4,609 research outputs found

    Neotropical Seasonally Dry Forests: Response of Soil Fungal Communities to Anthropogenic Actions

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    The aim of this review was to analyze the information available on soil fungal community of Neotropical Seasonally dry forests, with special attention given to the Chaco area. This review is focused on the loss of soil fungal community due to anthropogenic actions such as forest clearing. Over the last decades, the expansion of the agricultural frontier has had a wide range of physical, chemical and biological effects on Neotropical dry forests. As these changes on the Schinopsis dry forests (Chaco) have rendered the ecosystem vulnerable, these areas have become some of the few protected areas in South America. After analyzing both national and international studies to find the latest research available on the topic we have noticed there is lack of specific studies on soil fungal community in the Chaco area, unlike Cerrado and Caatinga where most studies have been carried out. Therefore, we propose to conduct more in-depth studies on soil fungi in Schinopsis forests to revalue the Chaco fungal community to use them as potential indicators of soil health and to develop new management techniques.Fil: Merlos, Cristina Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; ArgentinaFil: Pelizza, Sebastian Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Moreno, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; Argentin

    Color Engineering of Silicon Nitride Surfaces to Characterize the Polydopamine Refractive Index

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    A simple methodology to generate polydopamine (PDA) surfaces featured with color due to thin-film interference phenomena is presented. It is based on depositing ultra-thin films of polydopamine on a Si/Si 3 N 4 wafer that exhibits an interferential reflectance maximum right at the visible/UV boundary (∼400 nm). Therefore, a small deposit of PDA modifies the optical path, in such manner that the wavelength of the maximum of reflectance red shifts. Because the human eye is very sensitive to any change of the light spectral distribution at the visible region, very small film thickness changes (∼30 nm) are enough to notably modify the perceived color. Consequently, a controlled deposit of PDA, tune the color along the whole visible spectrum. Additionally, good quality of PDA deposits allowed us to determine the refractive index of polydopamine by ellipsometry spectroscopy. This data can be crucial in confocal skin microscopic techniques, presently used in diagnosis of skin tumors.Fil: Vega Moreno, Milena Amparo. Universidad de Salamanca; EspañaFil: Martín del Valle, Eva M.. Universidad de Salamanca; EspañaFil: Perez, Maximiliano Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo; ArgentinaFil: Pecharromán, Carlos. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia de los Materiales de Barcelona; EspañaFil: Marcelo, Gema. Universidad de Salamanca; Españ

    Estudio de prefactibilidad para el coprocesamiento de aceite de palma en la refinería de Cartagena

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    Este estudio presenta la prefactibilidad del coprocesamiento de aceite de palma crudo para la producción de diésel de ultra bajo azufre (ULSD) en la refinería de Cartagena, lo que contribuye a la disminución de la contribución de carbono por la sustitución del uso de combustibles provenientes del petróleo y, además, se presentan las cargas de origen vegetal como una alternativa para las refinerías en episodios de alta volatilidad en el precio del petróleo. Lo anterior se logra a partir de mezclar 5% en volumen de aceite de palma en la carga a las hidrotratadoras de diésel de alto azufre (HSD) para al final producir una mezcla con 95% de ULSD de origen del petróleo y 5% de aceite vegetal hidrotratado (HVO), que cumple las especificaciones de calidad combustible convencional para motores diésel. Con el objetivo de determinar la prefactibilidad de este proyecto, se hicieron los estudios de mercado, del entorno, técnicos, legales y financieros. Además, para la construcción de los estados de resultados proyectados el estudio se dividió en dos casos: el de coprocesamiento, en el que el producto se considera diésel de bajo azufre con precio internacional, y el de biodiésel, en el que se supuso que el HVO recibiría el reconocimiento del Ministerio de Minas y Energía, incentivo otorgado a los productores de biodiésel en Colombia. Por último, se presenta el análisis de sensibilidad, en el que se evaluó la influencia de la diferencia de precio entre la materia prima y el producto en el valor presente neto (VPN), que mostró que, para que este proyecto sea factible, se debe tener un diferencial de por lo menos de USD26 por barril procesado para que este indicador sea positivo. Para el caso de coprocesamiento se encontró que no es factible y para el de biodiésel que sí lo es.Because of the growing world energy demand, high volatility in the international oil prices and international agreements to reduce the greenhouse emissions coprocessing renewables feedstocks in the actual refineries represents an alternative to partially replace fossil fuels for diesel engines. In this manner, The aim of this project is to perform a pre-feasibility analysis of the coprocessing of palm vegetable oil to produce fuels in the Cartagena’s Refinery. In order to evaluate the prefeasibility of coprocessing of vegetable feedstocks in the Cartagena’s Refinery a market, an environment, a technical, a legal and a financial assessments will be carried out. In addition, the construction of the projected income statements is divided in two cases: the first one in named as “co-processing case” where the product is considered such as regular low sulfur diesel with international price and the second one the “biodiesel case”, which is considered that the HVO receives recognition from the incentive ministry given to biodiesel producers in Colombia. At the end of this document, a sensitivity analysis reveals that the net present value (NPV) of the co-processing vegetable feedstocks strongly depend on the price difference between the raw material (crude palm oil) and products (ULSD or Biodiesel). This study shows that minimum difference must be USD26 per barrel in order to consider the project feasible. Consequently, the main conclusion of this study is that the co-processing of vegetable palm oil (VO) in the Cartagena’s refinery for the ULSD production is a not profitable case in the actual international prices scenario (USD61 per barrel of VO, USD65 per barrel of ULSD). However, this study reveals that the biodiesel producers have price benefits in Colombia where the price is USD124 per barrel of VO produced. This makes the co – processing of vegetable oil profitable suggesting a legal and political work coming up
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